cyber crime discussion

 

 

 

 

 

 

 

 

Cyber Crime Discussion

Name of Student

Name of Instructor

Institution

Date

 

In one of the headlines of an article in 2013, Anonymous Hacks Department of Justice Website had threatened to launch ‘multiple warheads’. According to this article, a hacker by the name Anonymous had been linked with hacking of the United States Sentencing Commission website and managed to get away with sensitive information. In this case, the computer had been used as the main target of crime. According to Maras (2015), such cybercrimes where a computer is used as a main target are classified as category I cybercrimes.

Reports also indicated that the attack on the United States Sentencing Commission website was motivated by an earlier contravention of the 8th Amendment that prohibited against any form of cruel and unusual punishment on a hacker who had been previously arrested having been suspected for similar crime. Upon his arrest, the suspect had been promised to be set free on condition that s/he helped bring his accomplices to book, failure to which s/he was to face a jail term of 35 years. Having feared for the unknown regardless of his/her choice, the suspect resorted to take his own life than live to bear the consequences of either option.

As at the time of accessing the article, the anonymous propaganda was still available and could be accessed by members of the public. It was also revealed that after successfully hacking the system, Anonymous extracted the most sensitive information including the famous ‘warheads’ that are named after the Supreme Court Justices and thereafter threatened to spill it to the general public.

In order to avoid such cyber-attacks and other related crimes, I will take measures such as ejecting the hard drive and files that contain the most sensitive information from the internet server. This is one of the most effective measures especially when the hard drive completely unplugged from the server and in effect allowing only for manual access. I will also work to bar any remote access and add a redundancy to ensure that no form of access is permitted, just as in the case of Mission Impossible movie.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

References

Maras, M. H. (2015). Computer Forensics. Jones & Bartlett Publishers.

 

 

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BUSM7: Romance in the Workplace

 

 

Workplace Romance

 

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Institution

 

 

Views on Workplace Romance

Workplace romance refers to the welcoming of sexual interest by two people who belong to a particular organization (Parks, 2006). These relationships have become common in the current times due to the significant changes that have occurred in the workplace. Some of these changes include the larger number of women in the workplace and the long working hours by the employees, causing them to spend more time with each other than with their families.

Romance in the workplace should not be entertained due to the negative impact it has on the individuals involved and their families. An example is a hierarchical romance where exploitation can occur as the person in the lower level uses the sexual reliance of the one in the higher level to get favorable working conditions. On the other hand, the person in the higher level can use the reliance of the one in the lower level to gain an increase in the work performed forcefully.

Furthermore, when a romantic relationship comes to an end, becoming coworkers can prove to be difficult. Also, in the case one of the individuals involved, has the desire to continue with the relationship this can result in sexual harassment. Romance in the workplace, especially in the early stages, can reduce the productivity of the people involved. Additionally, this kind of relationship can result in these individuals divorcing the partners they have currently. Thus romance in the workplace should be discouraged (Pierce, 1998).

 Organizational Policies on Workplace Romance

There are differing views on whether romance in the workplace should be forbidden or not; some of the sexual harassment scholars argue that the harassment can disguise itself as romance (Pierce & Aguinis, 1997). Thus, there is a need for organizations to establish policies regarding some aspects of the romantic relationship at work. An example of a policy which an organization can develop is one which forbids romantic relationships between subordinates and their supervisors. Another policy would be in restricting the display of affection publicly between coworkers who are in a romantic relationship. In cases where the employees violate these policies, the management can transfer them to a different department or even terminate them from employment.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

References

Parks, M. (2006). Workplace Romance: Poll Findings: Society for Human Resource Management. Wall Street Journal.

Pierce, C. A. (1998). Factors associated with participating in a romantic relationship in a work environment. Journal of Applied Social Psychology28(18), 1712-1730.

Pierce, C. A., & Aguinis, H. (1997). Bridging the gap between romantic relationships and sexual harassment in organizations. Journal of Organizational Behavior, 197-200.

CRIMINAL PROFILE ANALYSIS

 

Crime scene assessment

The crime scene of the murder of Jane was a public place where people often flock for bird viewing and recreation. Therefore the offender was aware that the body would be spotted quickly. The offender also lit the body to make passers-by curious hence lead to its recovery. Another factor which indicates that the offender or offenders wanted the body to be spotted quickly is the fact that the weather at that time was conducive and people would most probably be outside. The location of the body was 30 yards from the road which means that it was perhaps brought by a vehicle and dropped a few steps from the road. The short distance from the road shows that it might have been one offender, but it does not necessarily mean it was one person because they might have been two or more people also. The seat of the fire was around the lower abdomen and the genital parts of the body, and therefore the offender might have sexually assaulted the victim, or it might have been a case of necrophilia. These assertions are backed up by the fact that she was undressed.

It is highly probable that Jane was held by the offender in an area around the town of Bletchingham because the Common is not far from the crime scene. The body seems to have been covered by a tarpaulin because of the metal eyelets found around it which makes the assertion that she was killed in another place and dumped there more profound. There are signs that she struggled to death because a pair of tights tightly tied her neck. The offender had an intention of burning the body because petrol ignited the fire. Therefore, the disposal method of the body might have been premeditated. There were no indications that the body had been at that spot for a long time hence the assumption that it might have been dumped there and set on fire a few minutes ago before being discovered are on track. Tests on the body revealed that the body had been dead for some weeks. Therefore, the offender might have killed her and kept the body before then dumping it in the Common.

The location of Jane’s shoes was near the pub she was going to, and the bus park. The indication of this is that she might have been accosted and taken away by force while walking to the pub after being dropped off at the bus stop. It is most likely that she resisted the capture and in the process, her shoe slipped off her foot. She might have been kept alive by the offender for approximately one and half months before being murdered because she disappeared on 24th May and her body discovered in mid-July.

Offender characteristics

The offender seems to have planned how to commit the crime very well. Jane was last seen at 6:30 PM when heading to the pub where she was going to meet her friends. The capturing must have happened few minutes from this time because she did not reach the pub which was a ten-minutes walking distance from the bus stop. It is most likely that the offender had been trailing the victim for some time and saw that it was easier to capture her at this time of the day, and at that place. Jane was alone and had earlier in the day spend some time with her fiancée. According to the report, this was the only time she was alone, and it was nearly falling dark making this crime look like a well-planned one. Moreover, Jane is described as a woman of regular routines and steady habits. The offender might have been aware of her movements over time and where she hangs out and at what time.

The offender seems like a person who was motivated by rage and maybe revenge because of the way he or she executed the crime. She seems to have been forcefully captured and most probably driven away in a vehicle because she was in a public place. The probability of the offender having planned the capture is high because if it was an ordinary theft or robbery, she would have been robbed and let free. Her detention gives advances the thought of the offender’s motivation to kill her. The offender seems to have planned to detain her and prepared a place or a room to take her after capturing her. Because Jane is friendly and a shy lady according to the report, it is not highly probable that she provoked the offender as she was heading to the pub. This assumption rules out a possibility of Jane provoking the offender before the offender becoming enraged and planning to kill her. The fact that the CCTV camera in the street where Jane was captured had been taken for repair recently before her capture shows that the killing was a premeditated act. The offender might have colluded with another person to make the CCTV system not to work to facilitate the offense.

The probable motivation for the killing might have been sexual because of the nature of the disposal of the body. Jane was naked at the time she was discovered, and her lower abdomen, specifically the genital area was burned. May be it was a case of the offender being rejected by Jane that triggered the rage to do away with her. It is likely that the offender decided to capture her and sleep with her during the one and half months and kill her so that she does not live to tell about it. The offender might have been motivated by showing her that he can control her and has authority over to her.

Further lines of inquiry

Some additional information which might help to identify the offender is closely focusing on people who she has been interacting with over time. It is highly probable that the person who killed Jane knew her and was very angry with her. The nature of the disposal of the body shows a person who was very angry and who was on a revenge mission because if the killing was a mistake, the body would not have been burned. Investigating people close to her will make it possible to know if the offender was a person known to her because he capture and disposal seem to have been done by a person who knew her. Another additional information which may assist to interpret the behaviour of the offender would be that the offender seems not to have asked for anything such as money or favour. This assumption cements the point that the killing was not motivated by an intention to steal. It is most likely that the offender was a disgruntled person who was on a revenge mission. The report does not indicate that one of her body organs was missing. Therefore, cannibalism is not an issue to consider.

Psychopathology in John

John is showing psychopathology in his treatment towards Valerie (Ormel J, Laceulle & Jeronimus 2014). As acquaintances observe, the physical and psychological abuse by John is increasing with time. John seems to have anger management issues because he gets furious due a minor provocation. Valerie is the target of John’s anger because she does not fight back. John wants to control Valerie entirely and projects his frustrations on her. John thinks that it is normal to punish Valerie and treats her like an object. The problem with the violence being meted on Valerie by John is that it is increasing with time. It began by kicking and punching at home and has escalated to using objects such as spanners and car doors to assault her in public. John seems to have an inferiority complex or a feeling of inadequacy because he attacks a person who does not fight back. He is a bully and bullies are people who have low self-esteem and oppress others to feel in control.

According to Mills & Kroner (2003), abusive partners are compulsive and cause severe physical and psychological trauma to the victim. The frequency of their attacks are frequent, and they have a sadistic satisfaction when they see their victims experiencing pain. That is the case with John. He seems to like the way he controls Valerie.

 

John’s attitudes towards, and perception of, his behaviour

John’s attitude towards his behaviour is positive. He feels that he should abuse her because he does not show any remorse. If John felt terrible about his actions, he would have shown signs of trying to change and trying to stop physically and verbally abusing Valerie. The fact that Valerie does not fight back and does not seek help makes John feel his actions are justified. He thinks that he is punishing Valerie and helping her become a better person, which is wrong because he is violating her human rights. John’s attitude and perception towards his behaviour make him continue. That is why he is threatening to punish her severely in future. He is not remorseful for his abusive actions and has an “I don’t care” attitude. His attitude towards his actions is causing him to become bold and even attack her in front of her friends. Therefore, John is likely to continue verbally and physically abusing Valerie because he feels that he is doing the right thing. For an individual to change, he or she must think that there is a need to change, but John has not realized his mistakes.

Factors maintaining John and Valerie’s relationship

According to Stroshine & Robinson (2003), most domestic violence victims just like Valerie do not want to leave because of dependence on the abuser financially, or due to religious beliefs. Another reason that may be causing Valerie not to leave is that maybe she feels that she has invested a lot in the relationship and leaving will mean that she loses what she has made in the two years. Also, she may be thinking that John will change and become a better person in future. Many domestic abuse victims fall into depression, and their self-esteem is lowered because of constant verbal abuse and being told that they are weak, ugly, and much more (Lysaker, Clements, Wright, Evans, & Marks, 2001). John verbally abuses Valerie and criticizes her appearance in front of people. Maybe this has lowered Valerie’s self-esteem to the extent that she feels worthless and unable to get another partner if she leaves John.

Another reason why maybe the relationship has not ended is that Valerie fears after leaving John he may harm her even more. According to Raj and Silverman (2003), some domestic violence victims fear to move on from a relationship because they fear being killed or harmed severely by their abusers. They feel that if they stay, they are safer which may be the case with Valerie who is not leaving despite the frequency and intensity of abuse is on the rise.

Two conflicting psychological offense profiles of this case

Adrian might have been set up by his friends while they were drinking. He remembers being in the third pub but does not remember when he came out of it or how he got into the room he was in with the two foreigners. It is most likely that his drink was spiked with his friends’ knowledge because why did they leave him with strangers. The different accounts given by his friends about what transpired gives a clue that they might have been involved in setting him up because why should they conceal details which would be helpful in getting to the bottom of the case. Adrian being an over-controlled person could not have engaged in sodomy just because of being tipsy. Therefore, it is most likely that his friends tricked him.

Another angle would be that Adrian wandered away from his friends and met with the foreigners who dragged him. The fact that he woke up eight hours after going home shows that he might have been under the influence of drugs. The imaginations he is having and the inability to remember whatever transpired during the night also indicates that he was spiked because he says that he had not drunk much to lose his memory. Therefore, maybe the foreigners saw him alone in the pub and put a drug in his drink and later on carried him to the room. He woke up naked and the foreigners were half naked. One of them told him that they enjoyed the night and they hope that he enjoyed too. The fact that they were conscious as he woke up indicates that they were not drunk as he hence were able to overpower and control him.

Psychological advice to investigators

I would advise the investigating team to adopt the first profile in which Adrian’s friends colluded with the foreigners. There are many indications why this profile is more profound compared to the second one. First, Adrian’s friends did not raise any alarm after he got lost. After he contacted them the following day, they did not bring up the topic of what happened the previous day. Moreover, the foreigners would have preferably left Adrian alone in the room after sexually assaulting him if they had not colluded with his friends. Telling him that they enjoyed the night shows that they did not care whether they were found doing it or not.

Adrian’s friends should have given the same account of events if there was nothing sinister in their actions. It is strange how they let him get lost and did not care what happened to him and did not report to the police, his friends, or family. Also, another strange thing with the friends is that they did not try to give Adrian information about how he got lost. They acted as if everything was okay while they were not. Therefore, it is more likely that Adrian’s friends knew what transpired in the night that he was allegedly sexually abused.

Actions and potential effects of “date rape” drugs

Most commonly used date rape drugs are alcohol-related. The sex offenders mostly use alcohol because the victims are likely to take it willingly without suspecting any foul play (Webber & Craig 2009). The drugs dissolve easily in alcohol and are not easy to discover when used on a victim. The victim’s drinks are mostly spiked after they have drunk to an extent where their conscience is impaired. They make the victims lose inhibitions and consciousness such that they cannot recollect whatever happens to them after they take them. It is not possible for the victim to remember whatever happened after the drug took a toll on them and the time they gained their consciousness. The “rape drugs” affect a victim’s sexual behaviour such that it may arouse the victim because it does away with consciousness hence the person lacks inhibitions of his or her actions. They may also cause aggressive sexual behaviour and dangerous sexual tendencies such as sex without protection (Webber & Craig 2009). They also lead to impaired judgment and loss of muscle power. The drugs make cause victims to black-out and may experience distorted images or hallucinations such as the images Adrian was seeing of being attacked by one of the foreigners. The drugs also cause a lot of sleep to the victim. Adrian slept the whole night and extra eight hours after leaving the room with the foreigners.

Source of Mary’s motivation

Mary’s most likely motivation is revenge. She was not part of the civil rights group, was not invited through a call, but just learned about the demonstration over the internet. Therefore, maybe Mary wanted to have revenge on a person who worked in the center and saw this as the best chance to do it. The report indicates that she traded insults with another female in the research centre. It is highly probable that that woman was the motivation behind her use of abusive behaviour and shouting. She is a sociable person and seems to have self-awareness because she doesn’t show peculiar behaviours when put in a room by the police. Therefore, Mary may have had a grudge with the other woman, and she decided to use the demonstration as the avenue to get back to her in the name of the demonstrations.

The fact that she came the three days show that she wanted very much to take part in the demonstration. The first two days Mary covered herself but uncovered herself to make her target person realize her. Therefore, it is highly probable that she was coming to embarrass the other woman who worked in the centre.Another source of Mary’s motivation might have come from the love of animals. However, her use of abuses during the demonstrations indicates that she might be suffering from aggression problems. Maybe she had frustrations in her life and didn’t have somewhere to pour them. She was aware that she was doing the wrong thing when abusing the workers because she covered her face. Moreover, she seemed to be aware of her actions.

The psychological mechanisms operating in Mary

Mary is most likely to be using the demonstration as a coping mechanism. Maybe Mary experienced a frustrating situation but is using the demonstration to cope with the pain. According to McMahon (2013), projection is a defense mechanism used by individuals to cope with stress whereby the person directs his or her frustrations to a lesser being to feel even. It is likely that Mary targeted the demonstrators because in a demonstration people are many and she will not be detected. The fact that she was not invited to the demonstration shows that she was not part of it, but invited herself to satisfy her needs.

Moreover, Mary covered herself with a scuff to hide her identity because she was aware that she was doing a wrong thing. It seems that abusing the workers of the research centre made her feel good and vindicated because she did not show any remorse after being arrested. When asked the reason for abusing the worker, Mary said that she intended to inform them to stop killing animals. However, her way of doing that was wrong but she does not show any regrets even after using unprintable words to refer to them.

Kramer & Ueli (2010) maintain that psychological mechanisms are aimed at making the individual feel at peace with themselves.  Therefore, it is highly likely that Mary wanted to offload her frustrations in the demonstration anonymously. It is not coincidental that she came for the demonstrations in three days and all those days she was the loudest and most abusive. If she was genuinely demonstrating, she could have behaved like the other demonstrators.

References

 

Buss, D.M. (2004).Evolutionary Psychology: The New Science of the Mind. Boston, MA. Pearson Education, Inc.

Kramer, Ueli (June 2010). “Coping and defence mechanisms: What’s the difference? – Second act”. Psychology and Psychotherapy: Theory, Research and Practice83 (Pt 2): 207–221.

Kroner, D. G., Mills, J. F., & Morgan, R. D. (2006). Social desirable responding and the measurement of violent and criminal risk: Self-report validity. Journal of Forensic Psychology Practice, 6(4), 27-42.

Lysaker, P. H., Clements, C. A., Wright, D. E., Evans, J., & Marks, K. (2001). Neurocognitive correlates of helplessness, hopelessness, and well-being in schizophrenia. Journal of Nervous and Mental Diseases, 180, 457–462.

McMahon, S. B. (2013). Wall and Melzacks textbook of pain. Philadelphia, PA: Elsevier/Saunders.

Ormel J, Laceulle OM, Jeronimus BF (2014). “Why Personality and Psychopathology Are Correlated: A Developmental Perspective Is a First Step but More Is Needed”European Journal of Personality28 (4): 396–98.

Raj, A., & Silverman, J. G. (2003). Immigrant South Asian women at greater risk from intimate partner violence. American Journal of Public Health, 93, 435–437.

Stroshine, M. S., & Robinson, A. L. (2003). The decision to end abusive relationships: The role of offender characteristics. Criminal Justice and Behaviour, 30, 97–117.

Webber, Craig (2009). Psychology & crime. London: Sage. p. 67.

Female Genitourinary Tract Infection.

Introduction

The Urinary Tract Infection (UTI) is a general term used to describe infections that affect any section of the urinary tract. Research shows that women are the most affected when compared to men. Approximately a third of adult females have been diagnosed with symptomatic cystitis episode at least once and there are chances for recurrent episodes. The incidence of UTI in males below 50 years of age is low while the female adults being 30 times more vulnerable than men in UTI contraction (Tan & Chlebicki, 2016). The infection can result to complex effects like renal failure and kidney damage when not eliminated or identified in the system. Proper UTI classification into complicated and simple forms aids in the management. Diagnosis is founded on a patient’s history with applicable investigations depending on personal risk factors.

Patients Initials: R. L

Subjective Data:

The clients complained about frequent, painful and burning urination, vaginal discharge, and severe lower abdominal pain (Stothers et al., 2016).

Chief Compliant:

“The urge of frequent urination is out of my control. I barely cannot help but find myself in the bathroom from time to time.”

History of Present Illness:

The 28 year old lady, R.L., reports that for the past two days she has been constantly visiting the bathroom for urination. A painful burning sensation is experienced during the urination. The lady claims that she cannot control the urge for urinating and finds herself in bathroom often. The symptoms she claims are related to the previous UTI that she had suffered from. The lady experiences increased lower abdominal pain and also noticed brown fouls of smelling discharge after having unprotected sex with the former boyfriend. The tubal ligation performed on her could also contribute to the frequent cases of UTI as there are chances of infections after the ligation.

PMH/Medical/ Surgical History:

Past Medical History (PMH):

The patient was diagnosed with UTI infection three times in the same year. She was positive for gonorrhea twice and chlamydia once. The client has had a total of four pregnancies and three viable offspring birth (gravida 4, para 3). The client was prescribed sulfamethoxazole / trimethoprim for the as the antibiotic drugs.

Surgical History:

The client underwent surgical tubal ligation as a method of birth control to avoid unnecessary pregnancies that may initiate abortion.

Medical History:

The last pap conducted on her was negative and the client declined of any breast discharge. The dark urine is an indication of blood present in the urine (hematuria) which is associated with UTI as it is accompanied with urine odor. Currently the patient is under no medication.

 

 

Allergies:

The client claimed to be allergic to deodorants perfumes and items with scents in that she develops rashes when exposed to them. The client is also affected by mold, grass, and pollen during the fall and spring seasons. The seasonal allergies initiate itchy eyes, headaches, and running nose and as a result, she gets tired. The client is also allergic to Augmentin drug and eggs.

Significant family History:

The client R.L. is the eldest child in a family of four siblings. The patient has three children and still single. She has a history of numerous male sexual partners. At the moment, the client is staying with a new boyfriend. Their dad died while she was at a tender age of 10. The mother did odd jobs to earn a living as she was just a house wife by the time the husband died. After completion of school, R.L. decided to start living on her own while she hunts for a job where she later started to engage in relationships seeking financial support from her partners.  She was able to give birth to 3 children against her wish and decided to take them to her mother’s home. Her mother claims to have UTI at some point in her life but that should not be linked to hereditable infections as the mother also had cases of multiple sex partners. She was once taken for counseling sessions for abstinence but she did not complete the sessions and termed as tiresome.

Her siblings are all male and everyone is independent. The fact that she is the only female child could put pressure on her that may have resulted to the present character. The family does not hold meetings to help one other as everyone claim to be busy. Due to the family attitude of everyone minding their own business could be another contributing factor for R.L‘s behavior. In her own efforts of preventing unnecessary pregnancies, she opted for the use of contraceptives for birth control. Just like her mom, the client has also undergone tubal ligation two years ago.

Social History:

The client is single, living with a new boyfriend and she is presently not employed. She does not smoke neither does she use alcohol nor drug abuse. She is an atheist and believes in no religion, only managed to complete her A –level. No history of childhood violence though family negligence can be observed. She is more comfortable in male company than female friends.

Review of symptoms:

Physical exam:

On assessment, the client’s blood pressure was 100/80, heat rate was 80 rate of respiration was 16, and the temperature was 99.7F. She is 5 inch in height and weighs 120. She appears to be relatively distressed. Her HEENT was of normal limits and showed no abnormalities. The heart rate was normal with normal rhythm S1 and S2. The chest was clear within the normal limits. The abdomen indicated a soft, tender, and high suprapubic inflammation. She admits of adnexal and cervical motion inflammation, and smelling vaginal discharge. Her rectal is within the normal limits with no abnormalities. Normal pulse rates with normal working of the brain.

Laboratory and Diagnostic Testing results.

Leukocytes differential:

Results: Neutraphils 68%, Bands 7%, Lymphs 13%, Monos 8%, EOS 2%.

Interpretation: An increased level of leukocytes in in the blood stream or urine often indicates presence of an infection (Heytens et al., 2017). The leukocytes or white blood cells are immune cells that fight infection and diseases hence presence in the system. The neutrophils level is higher than the rest due to its function of phagocytosis and killing bacteria.

Urine analysis:

Results: Straw colored urine, Specific gravity of 1.015, PH 8.0, Protein-negative, ketone-negative, glucose-negative, bacteria –many, Leukocytes 10-15, RBC 0-1.

Interpretation: The urine analysis indicated that the specific gravity for the clients’ urine is 1.015 with a PH of 8.0. The UTIs is known to increase the pH level of urine. The specific gravity is within the normal range (Pagano et al., 2017). Lower specific gravity than that indicates high water intake or low minerals intake while a higher value than that indicates dehydration, insufficient water, and electrolyte stress.

Urine gram stain:

Results: Presence of gram negative rods

Interpretation: Escherichia coli is a gram-negative bacterium with a rod-like shape present in UTI infections (Pagano et al., 2017).

Culture of vaginal discharge:

Results: Presence of Neisseria gonorrhoeae, and gram negative diplococci

Interpretation: During gram stain, presence of gram negative bacteria helps in identifying appropriate medication for the infection; diplococcic and E. coli are common in UTI (Ismael et al., 2017). The presence of the bacteria in the UT is the main cause of the smelly vaginal discharge.

Chlamydia test:

Results: positive chlamydia monoclonal AB, wet preparation and VDRL negative, KOH preparation.

Interpretation: Lower GT infections with chlamydia are generally asymptomatic in both men and women unless the test is done. Since the chlamydia is labile, the viability can be sustained by keeping the specimen in wet conditions (Price et al., 2018).

A negative test for VDRL means that the sample is free from syphilis. The KOH preparation was for fungal infection test.


 

Conclusion and recommendation

Urinary Tract Infections are one of the most common clinical microbial infections in females. The recurrent UTIs are less frequent and mainly caused by reinfection of the same bacteria (Price et al., 2018). Proper urine assessment, urine cultures, and some radiological procedures are needed to cancel recurrence causes and to examine potential anatomical urinary tract anomalies. The anti-microbial therapy is the initial standard for UTI treatment although other alternatives like probiotics, methenamine salts reduce antibiotics exposure (Ailes et al, 2018). Postcoital prophylaxis, antibiotic prophylaxis, and acute individual-treatment are effective and cheaper treatment strategies aimed at decreasing the recurrent UTIs number.

 

 

 

 

 

 

 

 

 

 

 

References.

Ailes, E. C., Summers, A. D., Tran, E. L., Gilboa, S. M., Arnold, K. E., Meaney-Delman, D., & Reefhuis, J. (2018). Antibiotics Dispensed to Privately Insured Pregnant Women with Urinary Tract Infections—United States, 2014. Morbidity and Mortality Weekly Report, 67(1), 18.

Heytens, S., De Sutter, A., Coorevits, L., Cools, P., Boelens, J., Van Simaey, L., … & Claeys, G. (2017). Women with symptoms of a urinary tract infection but a negative urine culture: PCR-based quantification of Escherichia coli suggests infection in most cases. Clinical Microbiology and Infection, 23(9), 647-652.

Ismail, M. D., Ali, I., Hatt, S., Salzman, E. A., Cronenwett, A. W., Marrs, C. F., … & Foxman, B. (2017). Association of Escherichia coli ST131 Lineage with risk of Urinary Tract Infection Recurrence among young women. Journal of global antimicrobial resistance.

Pagano, M. J., Barbalat, Y., Theofanides, M. C., Edokpolo, L., James, M. B., & Cooper, K. L. (2017). Diagnostic yield of cystoscopy in the evaluation of recurrent urinary tract infection in women. Neurourology and urodynamics, 36(3), 692-696.

Price, T. K., Hilt, E. E., Dune, T. J., Mueller, E. R., Wolfe, A. J., & Brubaker, L. (2018). Urine trouble: should we think differently about UTI? International urogynecology journal, 29(2), 205-210.

Stothers, L., Brown, P., Fenster, H., Levine, M., & Berkowitz, J. (2016). MP26-05 DOSE RESPONSE OF CRANBERRY IN THE TREATMENT OF LOWER URINARY TRACT INFECTIONS IN WOMEN. The Journal of Urology, 195(4), e355.

Tan, C. W., & Chlebicki, M. P. (2016). Urinary tract infections in adults. Singapore medical journal, 57(9), 485.

 

Aircraft Propeller Systems

 

 

AIRCRAFT PROPELLERS

Author

Professor

Class

Institutional Affiliation

Date Submitted:

 

 

 

 

 

 

 

 

 

 

Question 1: Comparison of the design features of the propeller and propeller systems on single 1930s single piston racing aircraft to a single piston Unlimited Class racer.

Both the 1930s single piston racers and the present day Unlimited Class racer basically incorporate the same aircraft design. The defining requirement of an aircraft to enter the modern Unlimited Class racing is the utilization of a piston engine (Anon., 2013). This has made it more appropriate for the racing mechanics to remodel the old World War birds such as the P15 Mustangs into racers.

The race gives flight mechanics an opportunity to incorporate innovation in the design of the propeller and propeller systems of their aircraft. For instance, some of the single piston aircrafts which participate in the race have specialized combustion engines which burn aluminum instead of the general purpose jet fuel (Anon., 2014). This ensures that the little old birds are able to accommodate forces greater than 6g. This kind of acceleration was not a common thing in the 1930s single piston aircraft since the propulsion systems during the period could not keep up with such accelerations. In fact, even the modern day fighter jets require the pilots to wear special suits before performing accelerations which push their aircraft to such forces. With the kind of air frame technology that has been used in the design of the piston engine aircraft, it only leaves one wondering the kind of ingenuity that goes into the design of propeller system that is capable of such stress while racing these old planes.

Another major design difference between the two birds is the design and direction of rotation of the propellers. This is mostly due to the nature of the pylons used at the Unlimited Class racing which makes provisions for left turns only. From a pilot’s view, a propeller which has an anticlockwise rotation tends to raise the right wing of the aircraft while negotiating these corners. These has resulted in a major design change whereby the propellers of the racing aircraft are refitted to rotate clockwise- which is a major difference from the 1930s single piston engines. The massive effect of the direction of rotation of a propeller is most evident in helicopters. This is the single point in which the effects of rotation are best demonstrated and how catastrophic things can go if and when the normal rotation is affected. Therefore, the modern racing aircraft are a demonstration of pure innovation and the achievements that have been made this far to incorporate propellers in fixed wing light aircraft.

The two birds share a basic engine propulsion system. This is characterized by the single crank shaft system responsible for rotating fixed pitch propellers. However, the Unlimited Class racers feature various adjustable pitch propellers but this is not a standard deployment (Welch, 1989). Instead, the ground crew and designers are always given the liberty and freedom to tweak these features in order to ensure optimum aircraft performance and the assurance of finishing the race in spite of the extra stress that the aircraft is subject to.

The Unlimited Class birds are mostly much faster and develop more horsepower than their 1930s counterparts. This is partly due to the freedom of the ground crew in choosing the propellant material that is used in the engines. However, some design differences have also led to marked difference in these aircrafts’ propellant system. For instance, most of the participating airframes have their wings clipped partly to reduce the overall drag exerted on them (Lawless & Shaheen, 1988). This has contributed to their remarkable speeds which can easily exceed 500mph while utilizing engines that develop nearly the same amount of power as their old counterparts.

Whereas both airframes utilize the blade element theory for their propellers, the Unlimited Class racers seem to utilize this design concept much more than their 1930s racing counterparts. The logic behind using this design concept stems from the fact that these planes have always been required to perform extraordinary maneuvers. These include sudden and steep climbs, descents and turns which characterized the racing environments of both the 1930 –which was partly influence by military use and the present day sharp cornered turns over the pylons a the race field.

Frank Monroe Hawks Miller HM. Obtained from Air racers

Question 2: Analysis of the Design Features and Systems Expected to be found on a propeller system to be fitted on a large four engine turbo-prop aircraft flying up to 420 knots and performing STOL operations from jungles, deserts and over the arctic regions.

Turbine propellers (turbo-props) feature hot compressed gases rotating turbines which in turn rotate the propeller systems. The aircraft in question shall need to fly at relatively fast speeds; which is an important propeller design consideration for such an aircraft. The fact that the plane is fitted with four engines is also an important precursor of the possible propeller systems that can be fitted unto the system. Indigenously, STOL operations require that an aircraft should be able to land and take off over short runways (Haulman, 2011)- another important consideration for the propeller system that should be used.

It is expected that the aircraft has an adjustable pitch as opposed to a fixed-pitch propellers. This is due to the fact that it has to perform STOL operations and yet it will be required to fly over long distances: – a fact that is implied by the number of engines that it has. The adjustable pitch of the propellers will make it possible for pilot to tilt them in such a way that reduces drag most hence have the capability of developing more thrust and lift necessary for taking off from a short runway. Most aircraft whose propeller pitch is fixed are either optimized for cruising or STOL operations (Kinney, 2000). Therefore, the fact that the propeller on this system is adjustable will give the pilot the opportunity to perform STOL but still find pitch optimizations while cruising over long distances which the aircraft is most probably designed to accomplish.

Image of turbo-prop engine. Obtained from Glen center, NASA

The aircraft’s engines which house the propeller systems are expected to be positioned as close to the fuselage as is possible. As the propellers develop thrust at their front surfaces, being close to the airframes will ensure that as much wing surface areas as possible is available in order to develop lift much faster and more efficiently (Byers, 2004). Although the propellers are expected to send a thrust of air over the wings for extra lift, the fact that the craft will be cruising for 420 knots for most of the distance means that there will be enough lift from the airflow hence further warranting the position of the engines.

Each individual engine is expected to have as many propellers as possible per shaft. These could be more than four. Although this design reduces the general efficiency of each propeller, it makes it possible for propellers tips to rotate just below Mach 1. This will make the aircraft less noisy which is a general environmental concern especially in the jungles where it could disturb the existing fauna diversity. This will also make the control surfaces more maneuverable and responsive at lower speeds.

The fact that the aircraft is supposed to fly in dry deserts and cold arctic regions of the world presents a major expectation for the plane’s cooling system. Firstly, it must be able to accommodate overheating problems rampant in desert regions while at the same time avoiding the freezing of propeller systems in the arctic while the craft has stayed on the ground for elongated periods of time. Therefore, it will be expected that each engine incorporates a hybrid cooling system that will make it possible for the propeller system to be cooled by either water in hot conditions or air in the arctic regions. Water is likely to thaw around the engine areas while the aircraft is grounded in the arctic regions (Pavelec, 2004). Therefore, it would be necessary for the engine and propeller compartments to accommodate for this possible eventuality which might destroy the engine system.

Desert and arctic regions have markedly different atmospheric pressures which is a very important consideration for designing propeller systems. The hot air in desert is mostly characterized by low pressure while the arctic regions have relatively higher pressures. This affects the amount of air speed above the wings that is required to generate a lift for take-off. This means that the aircraft’s propeller system should yield enough horsepower to offset the drag experienced on the propellers which might need to have greater pitches in order to perform a STOLL operation in deserts (Stevenson, 1990). In addition, the propellers should be able to accommodate reverse thrusts which will serve as brakes on landing in the arctic. This is especially true given the fact that the already short runway might be snowy hence the need to apply extra breaking via the propellers.

 

 

Image obtained from Scriebel.com

Question 3: Analysis of design features and propeller theory expected on a propeller fitted to a single engine tail wheel fighter aircraft developing less than 100 hp compared to a modern light aircraft with tricycle undercarriage.

The propeller theory gives mathematical references towards designing systems that are either focused on blade element or momentum of the forces acting on the propeller per unit time of flight. It would be expected that the First Word War fighters are fitted with non-adjustable propeller pitches. This could partly be attributed to the fact that the warring countries needed to produce a very large quantity of aircrafts which were often destroyed just as fast as they were being produced from the factory lines (pavalec, 2005). However, the same will not be expected in a modern small aircraft. There is much more competition from commercial aircraft manufacturers such as Cessna who have mastered the art of producing such low cost effective aircraft. Due to this kind of competition, it has become necessary to optimize the functionalities of the individual planes and this will include incorporated including as much control for the pilot as possible in controlling the propeller of the plane.

Most of the small aircrafts tend to be trainers which are usually handled by inexperience pilot trainees, and who ‘love’ their lives very much. During the First World War, it was common for war time pilots to sacrifice their lives by flying right into other aircraft during combat missions. This necessitated the need for a propeller system that could maintain a steady course as much as possible, something that is still admired in today’s aviation industry. However, the extensive use of smaller airplanes in training activities has necessitated the need to incorporate as much control and automatic systems as possible in order to ensure that the students can complete their classes without a major incident. Among others, the modern propeller systems are designed in such a way that they can even recover from a stall which can save a panicked and shocked pilot trainee- something that could not be possible with the First World War aircrafts.

The tail-wheel design of the First World fighters increased the angle of attack of the wings while plane is taking off. This is different from the modern tricycle undercarriage aircrafts which are almost lateral to the ground surface while on the ground. However, the fact that the wheels of the old fighters could never be retracted meant that any propeller advantage gained over the modern design was cancelled as soon as the aircraft got airborne (Harvey, 1992). The modern light aircrafts could tap into this advantage if they got their undercarriage slightly elongated. This would in turn provide a natural increased angle of attack for the mass of air released over the surface of the wings by the rotating propeller. Consequently, this kind of design would be able to server STOL operations much better and efficiently. However, the general aesthetic design of this system would not be as appealing and this could reduce the market share of a company trying out such an innovation. This is makes it necessary to include aesthetic design considerations in the building of propeller systems.

A modern lightweight aircraft is expected to incorporate the principles of blade element more that First World War fighter aircraft. The blade element theory utilizes the principles behind the functioning of a normal wing, by increasing the curvature at the front more than the one at the back side (Thompson, 2004). This, in effect, creates a kind of lift towards the front which is in essence the generated thrust for the aircraft. Consequently, the modern light aircraft is capable of deriving more thrust from the action of the propeller. This means that a smaller engine is capable of developing as much power as did a larger engine fitted on a fighter during World War I.

Conclusion

Aircrafts with a single piston have been around since 1903 and are likely to stay around for quite some time. The single piston racing aircraft from the 1930s are basically the same airframes and engine technologies being used in the modern Unlimited Class racing. The modern racing birds are however much more modified than their old counterparts. Some of these modifications include the freedom of the ground crew to use fuels of their choices, tweaking the propeller rotation systems and reductions gears and redesigning the wing control surfaces among others. These endeavors have ensured that each racing pilot gets as much edge as possible over the other competitors and harnessing higher speeds and more resilience on the g force being exerted on the aircraft.

A turbo-prop four engine aircraft used in STOL operations has a set of unique propeller requirements that could enable it perform its job optimally. Among others, the pitch of the propellers will need to be adjustable so that the pilot can continuously optimize the performance of the propellers while flying under different air speeds and conditions. These are primarily dictated by speed requirements while taking off and those that come into the picture while the plane is cruising. The propeller theory is a comprehensive mathematical design consideration which is used in propellers. This theory makes a designation for designing propeller based on the moment created the blast of air pushed by the propellers per unit time, blade theory and vortex theory. The first two approaches are the most commonly design approaches while the vortex theory is rather mathematically complex hence does not receive as much attention by designers as otherwise could be necessary. General expectations dictate that modern small aircrafts make a combination of the lessons learnt over the period of aviation design and as such make as much flight optimizations as possible for the best flying experiences.

 

 

 

 

 

 

References

Anon., 2013. YouTube. [Online] Available at:           https://www.youtube.com/watch?v=_HWD3iJtTpU

Anon., 2014. You Tube. [Online] Available at:          https://www.youtube.com/watch?v=o7EIxneD4f8

Byers, R., 2004. Dreams of Flight: General Aviation in the United States (review). Technology     and Culture, pp. 628-630.

Harvey, J. R., 1992. Regional Ballistic Missiles and Advanced and Strike Aircraft: Comparing     Military Effectiveness. International Security, pp. 41-83.

Haulman, D., 2011. The Tuskegee Airmen and teh “Never Lost a Bomber” Myth. Alabama           REview, pp. 30-60.

Kinney, J. R., 2000. Curtis-Wright: Greatness and Decline (review). Technology and Culture, pp. 147-149.

Lawless, R. & Shaheen, T., 1988. Airplanes and Airports: The Subtle Skill of Japanese      Protectionism. SAIS Review, pp. 101-120.

pavalec, S. M., 2005. Hitler’s Jet Plane: the Me 262 Story (review). The Journal of Military            History, pp. 877-890.

Pavelec, S. M., 2004. 100 Years of Air Power & Aviation (review). The Journal of Military           History, pp. 1318-1321.

Stevenson, G., 1990. Canada and International Civial Aviation, 1932-1948 by David MacKenzie (review). The Canadian Historical review, pp. 412-414.

Thompson, W., 2004. Chasing the Silver Bullet: U.S. Air Force Weapons Development from        Vietnam to Desert Storm. The Journal of Military History, pp. 1014-1017.

Welch, J., 1989. Assessing the Value of Stealthy Aircraft and Cruise Missiles. International          Security, pp. 47-63.

 

 

Aircraft Propeller Systems

 

 

AIRCRAFT PROPELLERS

Author

Professor

Class

Institutional Affiliation

Date Submitted:

 

 

 

 

 

 

 

 

 

 

Question 1: Comparison of the design features of the propeller and propeller systems on single 1930s single piston racing aircraft to a single piston Unlimited Class racer.

Both the 1930s single piston aircraft racers and the present day Unlimited Class airplanes are built on the same design. The most important requirement of an aircraft to enter the modern Unlimited Class racing is the utilization of a piston engine (YouTube.com, 2013). This has made it more appropriate for the racing ground crew to remodel the old World War aircrafts such as the P15 Mustangs into racers.

There is a major design difference between 1930s racing aircraft and the airplanes participating in Unlimited Class races. This is particularly true in the design and direction of rotation of the propellers. This is mostly due to the nature of the pylons used at the Unlimited Class racing which makes provisions for left turns only. From a pilot’s view, a propeller which has an anticlockwise rotation tends to raise the right wing of the aircraft while negotiating these corners. This has resulted in a major design change whereby the propellers of the racing aircraft are refitted to rotate clockwise- which is a major difference from the 1930s single piston engines. The effect of the direction of rotation of a propeller is most evident in turbo shaft aircrafts such as helicopters. This is the single point in which the effects of rotation are best demonstrated and the adverse effects when the desired propeller rotation is affected (Aerospace.org, 2015). Therefore, the modern racing aircraft are a demonstration of the achievements that have been made this far in incorporating propellers in fixed wing light aircraft while taking into account the effects and forces associated with their rotation.

The Unlimited Class event gives flight mechanics an opportunity to incorporate new innovative designs into the propeller and propeller systems of their aircraft. For example, some of the single piston aircrafts which participate in the race have specialized combustion engines which burn aluminum instead of the general purpose jet fuel (YouTube.com, 2014). This ensures that the relatively old aircraft are able to accommodate forces greater than 6g. This kind of acceleration was not a common achievement in the 1930s for single piston aircraft since the propulsion systems during the period could not keep up with the resultant stress. In fact, even the modern day fighter jets require the pilots to wear special suits before performing accelerations which push their aircraft to such limits. With the kind of air frame technology that has been used in the design of the piston engine aircraft, it only leaves one wondering the kind of ingenuity that goes into the design of a propeller system that is capable of such stress while racing these old planes.

The aircraft from both eras share a basic engine propulsion system. This is characterized by the single crank shaft system responsible for rotating fixed pitch propellers. However, the Unlimited Class racers feature various adjustable pitch propellers although this is usually not a standardized requirement (Association, 2018). Instead, the ground crew and designers are always given the liberty and freedom to tweak these features in order to ensure optimum aircraft performance and the assurance of finishing the race in spite of the extra stress that the aircraft is subject to.

The Unlimited Class aircraft are much faster and develop more horsepower than their 1930s counterparts. This is partly due to the freedom of the ground crew in choosing the propellant material that is used in the engines. However, some design differences have also led to marked difference in these aircrafts’ propellant system. For instance, most of the participating airframes have their wings partly clipped in order to reduce the overall drag exerted on them (Lawless & Shaheen, 1988). This has contributed to their remarkable speeds which can easily exceed 500mph while utilizing engines that develop nearly the same amount of power as their old counterparts.

Whereas both airframes utilize the blade element theory for their propellers, the Unlimited Class racers seem to utilize this design concept much more than their 1930s racing counterparts. The logic behind using this design concept arises from the fact that these planes have always been required to perform extraordinary maneuvers. These include sudden and steep climbs, descents and turns which characterized the racing environments of the 1930s –which were partly influence by military use and the present day sharp cornered turns over the pylons a the race field.

Frank Monroe Hawks Miller HM. Obtained from Air racers

Question 2: Analysis of the Design Features and Systems Expected to be found on a propeller system to be fitted on a large four engine turbo-prop aircraft flying up to 420 knots and performing STOL operations from jungles, deserts and over the arctic regions.

Turbine propellers (turbo-props) work by means of hot compressed gases rotating turbines which in turn rotate the propeller systems. The aircraft in question shall need to fly at relatively fast speeds; which is an important propeller design consideration for such an airplane. The fact that the plane is fitted with four engines is also an important consideration of the possible propeller systems that can be incorporated into its body. Indigenously, STOL operations require that an aircraft should be able to land and take off over short runways (Watson, 1981)- another important consideration for the propeller system that should be used.

It is expected that the aircraft has an adjustable pitch as opposed to a fixed-pitch propeller system. This is due to the fact that STOL operations require optimized power generation from the propellers. Moreover, this aircraft will be required to fly over long distances: – a fact that is implied by the number of engines that it has. The adjustable pitch of the propellers will make it possible for the pilot to tilt them in such a way that reduces drag to the fullest which will enable them to develop the capability of developing more thrust and lift necessary for taking off from a short runway. The pitch for which an aircraft’s propeller is mounted is either designed to accommodate cruise speeds or other STOL operations (University of Southampton, 2018). Therefore, the fact that the propeller on this system is adjustable will give the pilot the opportunity to perform STOL but still find pitch optimizations while cruising over long distances for which the aircraft is most probably designed to accomplish.

Image of turbo-prop engine. Obtained from Glen center, NASA

Propellers are usually mounted in or on the engine system and are expected to be positioned as close to the fuselage as is possible. As the propellers develop thrust at their front surfaces, being close to the airframes will ensure that as much wing surface area as possible is available in order to develop lift much faster and more efficiently without affecting the wing’s design dynamics(Airlines.net, 2002). Moreover, the propellers are expected to send a thrust of air over the wings for extra lift. Therefore, the fact that the aircraft will be cruising for 420 knots for most of the distance will mean that there will be enough lift from the airflow hence further warranting the position of the engines being near the fuselage.

It is desirable to mount as many propellers as possible per engine shaft. These could be more than four. Although this design reduces the general efficiency of each propeller, it makes it possible for propellers tips to rotate just below the speed of sound (Mach 1). This will make the aircraft less noisy which is a general environmental concern especially in the jungles where it could disturb the existing wildlife diversity. In addition, more propellers per shaft will also make the control surfaces more maneuverable and responsive at lower speeds.

Flying aircraft in extreme climatic conditions such as dry deserts and cold arctic regions of the world presents a major expectation in the design of the plane’s cooling system. Firstly, it must be able to accommodate overheating problems rampant in desert regions while at the same time avoiding the freezing of propeller systems in the arctic regions while the craft has stayed on the ground for elongated periods of time. Therefore, it will be expected that each engine incorporates a hybrid cooling system that will make it possible for the propeller system to be cooled by either water in hot conditions or air in the arctic regions. Ice is likely to form around the engine regions while the aircraft is grounded in the arctic regions (Technische Universitat Darmstadt, 2016). Therefore, it would be necessary for the engine and propeller compartments to be designed in such a way that accommodates this factor.

Atmospheric pressures in desert and arctic regions are markedly different which create a very important consideration for designing propeller systems. The hot air in deserts is mostly characterized by low pressure while the arctic regions have relatively higher pressures. This affects the amount of air speed above the wings that is required to generate a lift for take-off. This means that the aircraft’s propeller system should yield enough lifting power to offset the drag experienced on the propellers which might need to have greater pitches in order to perform a STOLL operation in extreme and rugged conditions (NASA, 1997). In addition, the propellers should be able to accommodate reverse thrusts which will serve as brakes on landing in the arctic. This is especially true given the fact that the already short runway might be snowy hence the need to apply extra breaking via the propellers.

 

 

Image obtained from Scriebel.com

Question 3: Analysis of design features and propeller theory expected on a propeller fitted to a single engine tail wheel fighter aircraft developing less than 100 hp compared to a modern light aircraft with tricycle undercarriage.

It is important that the various propeller theories are applied in designing systems that are either focused on blade element or momentum of the forces acting on the propeller per unit time in order to create lift for flight. It would be expected that the First Word War fighters are fitted with non-adjustable propeller pitches. This could partly be attributed to the fact that the warring countries needed to produce a very large quantity of aircrafts which were often destroyed just as fast as they were being produced from the factory lines (ethw.org, 2015) which scrapped any need to fit them with the relatively expensive pitch adjustable propellers. However, the same will not be expected in a modern small fighter aircraft. There is much more competition from commercial aircraft manufacturers such as Cessna who have mastered the art of producing such low cost effective aircraft. Due to this kind of competition, it has become necessary to optimize the functionalities of the individual planes and this will include fitting them with as much control for the pilot as possible for the pilot’s control systems.

Small fighter aircrafts are usually handled by inexperienced pilot trainees. During the First World War, it was common for war time pilots to sacrifice their lives by flying right into other aircraft during combat missions. This necessitated the need for a propeller system that could maintain a steady course as much as possible, and indeed maintaining a steady course is something that is still admired in today’s aviation industry. However, the extensive use of smaller airplanes in training activities has necessitated the need to incorporate as much control and automatic systems as possible in order to ensure that the students can complete their flying classes without a major incident. Among others, the modern propeller systems are designed in such a way that they can even recover from a stall which can save a panicked and shocked pilot trainee- something that could not be possible with the First World War aircrafts.

First World War fighters had a shorter tail wheel which gave the wings an increased angle of attack against the air while the plane is taking off. This is different from the modern tricycle undercarriage aircrafts which are almost lateral to the ground surface while on the ground. However, the fact that the wheels of the old fighters could never be retracted meant that any propeller advantage gained over the modern design was reversed as soon as the aircraft took into the sky (Century of Flight, 2018). The modern light aircrafts could tap into this advantage if they got their undercarriage slightly elongated. This would in turn provide a natural increased angle of attack for the mass of air released over the surface of the wings by the rotating propeller. Consequently, this kind of design would be able to server STOL operations much better and efficiently. However, the general aesthetic design of this system would not be as appealing and this could reduce the market share of a company trying out such an innovation.

Blade element theory would be an important consideration in a modern lightweight aircraft whereas First World War fighter aircrafts might not incorporate this principle. The blade element theory utilizes the principles behind the functioning of a normal wing, by increasing the curvature at the front more than the one at the back side (Aerodynamics for Students, 2016). This, in effect, creates a kind of lift towards the front which is in essence the generated thrust for the aircraft. Consequently, the modern light aircraft is capable of deriving more thrust from the action of the propeller. This means that a smaller engine is capable of developing as much power as did a larger engine fitted on a fighter during World War I.

 

Conclusion

Aircrafts with a single piston have been around since 1903 and are likely to stay around for quite some time. The single piston racing aircraft from the 1930s basically have the same airframes and engine technologies being used in the modern Unlimited Class race. The modern racing airplanes are however much more modified than their old counterparts. Some of these modifications include the freedom of the ground crew to use fuels of their choices, tweaking the propeller rotation systems and reductions gears and redesigning the wing control surfaces among others. These changes have ensured that each racing pilot gets as much edge as possible over other competitors and harnessing higher speeds and more resilience on the g force being exerted on the aircraft.

A turbo-prop four engine aircraft used in STOL operations has a set of unique propeller requirements that could enable it perform its job optimally. Among others, the pitch of the propellers will need to be adjustable so that the pilot can continuously optimize the performance of the propellers while flying under different air speeds and conditions. These are primarily dictated by speed requirements while taking off and those that come into the picture while the plane is cruising. The propeller theory is a comprehensive mathematical design consideration which is used in propellers. This theory makes a designation for designing propellers based on the moment created by the blast of air pushed by the propellers per unit time. The first two approaches are the most commonly design approaches while the vortex theory is rather mathematically complex hence does not receive as much attention by designers. General expectations dictate that modern small aircrafts make a combination of the lessons learnt over the period of aviation design and as such make flight optimizations as possible in order to harness the best flying experiences from the propeller system.

 

 

 

 

 

 

 

 

 

References

Aerodynamics for Students, 2016. Blade Element Theory for Propellers. [Online] Available at:            http://s6.aeromech.usyd.edu.au/aerodynamics/index.php/sample-page/propulsion/blade      element-propeller-theory/[Accessed January 2018].

Aerospace.org, 2015. Helicopter Rotation Conventions. [Online] Available at:         http://www.aerospace.org [Accessed 28 January 2018].

Airlines.net, 2002. Under Wing Engines Vs Tail Mounted Engines. [Online] Available at:            http://www.airliners.net/forum/viewtopic.php?t=138213      [Accessed January 2018].

Association, U. S. R., 2018. Unlimited Class Specifications. [Online] Available at:  http://www.usrainfo.org       [Accessed January 2018].

Century of Flight, 2018. Development of Aviation Technology. [Online] Available at:         http://www.century-of            flight.net/Aviation%20history/evolution%20of%20technology/Variable      Pitch%20Propellers.htm            [Accessed January 2018].

ethw.org, 2015. World War II Aircrat. [Online] Available at:            http://ethw.org/World_War_II_Aircraft            [Accessed January 2018].

Lawless, R. & Shaheen, T., 1988. Airplanes and Airports: The Subtle Skill of Japanese      Protectionism. SAIS Review, pp. 101-120.

NASA, 1997. Boundary Layer Control, STOL, V/STOL Aircraft Research. [Online] Available at:            https://history.nasa.gov/SP-3300/ch8.htm      [Accessed January 2018].

Technische Universitat Darmstadt, 2016. What causes ice formation on aircrafts during flight?.     [Online] Available at: https://phys.org/news/2016-01-ice-formation-aircrafts-flight.html            [Accessed January 2018].

University of Southampton, 2018. Curtis-Wright: Greatness and Decline (review). [Online]           Available at:            https://www.southampton.ac.uk/~jps7/Aircraft%20Design%20Resources/aerodynamics    Bristol%20University%20Breguet%20range%20eqn.pdf        [Accessed January 2018].

Watson, D., 1981. The Tuskegee Airmen and teh “Never Lost a Bomber” Myth. [Online]    Available at: https://ntrs.nasa.gov    [Accessed January 2018].

YouTube.com, 2013. YouTube. [Online]        Available at:    https://www.youtube.com/watch?v=_HWD3iJtTpU            [Accessed January 2018].

YouTube.com, 2014. You Tube. [Online]       Available at:    https://www.youtube.com/watch?v=o7EIxneD4f8            [Accessed January 2018].

 

 

Aircraft Propeller Systems

 

 

AIRCRAFT PROPELLERS

Author

Professor

Class

Institutional Affiliation

Date Submitted:

 

 

 

 

 

 

 

 

 

 

Question 1: Comparison of the design features of the propeller and propeller systems on single 1930s single piston racing aircraft to a single piston Unlimited Class racer.

Both the 1930s single piston aircraft racers and the present day Unlimited Class airplanes are built on the same design. The most important requirement of an aircraft to enter the modern Unlimited Class racing is the utilization of a piston engine among other requirements which ensure that only the very old aircraft enter the race (Ahlstrom, 2000). This has made it more appropriate for the racing ground crew to remodel the old World War aircrafts such as the P15 Mustangs into racers.

There is a major design difference between 1930s racing aircraft and the airplanes participating in Unlimited Class races. This is particularly true in the design and direction of rotation of the propellers. This is mostly due to the nature of the pylons used at the Unlimited Class racing which makes provisions for left turns only. From a pilot’s view, a propeller which has an anticlockwise rotation tends to raise the right wing of the aircraft while negotiating these corners. This has resulted in a major design change whereby the propellers of the racing aircraft are refitted to rotate clockwise- which is a major difference from the 1930s single piston engines. The effects of the direction of rotation of a propeller are most evident in turbo shaft aircrafts such as helicopters. This is the single point in which the effects of rotation are best demonstrated and the adverse effects when the desired propeller rotation is affected (Aerospace.org, 2015). Therefore, the modern racing aircraft are a demonstration of the achievements that have been made this far in incorporating propellers in fixed wing light aircraft while taking into account the effects and forces associated with their rotation.

The Unlimited Class event gives flight mechanics an opportunity to incorporate new innovative designs into the propeller and propeller systems of their aircraft. For example, some of the single piston aircrafts which participate in the race have specialized combustion engines which burn aluminum instead of the general purpose jet fuel. Aluminum, when properly used as a source of fuel can burn with a higher density and yield more power (Massachussets Institute of Technology, 2017). This ensures that the relatively old aircraft are able to accommodate forces greater than 6g. This kind of acceleration was not a common achievement in the 1930s for single piston aircraft since the propulsion systems during the period could not keep up with the resultant stress. In fact, even the modern day fighter jets require the pilots to wear special suits before performing accelerations which push their aircraft to such limits. With the kind of air frame technology that has been used in the design of the piston engine aircraft, it only leaves one wondering the kind of ingenuity that goes into the design of a propeller system that is capable of such stress while racing these old planes.

The aircraft from both eras share a basic engine propulsion system. This is characterized by the single crank shaft system responsible for rotating fixed pitch propellers. However, the Unlimited Class racers feature various adjustable pitch propellers although this is usually not a standardized requirement (Hassel, 2012). Instead, the ground crew and designers are always given the liberty and freedom to tweak these features in order to ensure optimum aircraft performance and the assurance of finishing the race in spite of the extra stress that the aircraft is subject to.

The Unlimited Class aircraft are much faster and develop more horsepower than their 1930s counterparts. This is partly due to the freedom of the ground crew in choosing the propellant material that is used in the engines. However, some design differences have also led to marked difference in these aircrafts’ propellant system. For instance, most of the participating airframes have their wings partly clipped in order to reduce the overall drag exerted on them (Lawless & Shaheen, 1988). This has contributed to their remarkable speeds which can easily exceed 500mph while utilizing engines that develop nearly the same amount of power as their old counterparts.

Whereas both airframes utilize the blade element theory for their propellers, the Unlimited Class racers seem to utilize this design concept much more than their 1930s racing counterparts. The logic behind using this design concept arises from the fact that these planes have always been required to perform extraordinary maneuvers. These include sudden and steep climbs, descents and turns which characterized the racing environments of the 1930s –which were partly influence by military use and the present day sharp cornered turns over the pylons a the race field.

Frank Monroe Hawks Miller HM. Obtained from Air racers

Question 2: Analysis of the Design Features and Systems Expected to be found on a propeller system to be fitted on a large four engine turbo-prop aircraft flying up to 420 knots and performing STOL operations from jungles, deserts and over the arctic regions.

Turbine propellers (turbo-props) work by means of hot compressed gases rotating turbines which in turn rotate the propeller systems. The aircraft in question shall need to fly at relatively fast speeds which are an important propeller design consideration for such an airplane. The fact that the plane is fitted with four engines is also an important consideration of the possible propeller systems that can be incorporated into its body. Indigenously, STOL operations require that an aircraft should be able to land and take off over short runways (Daniel Hallman, 2011)- another important consideration for the propeller system that should be used.

It is expected that the aircraft has an adjustable pitch as opposed to a fixed-pitch propeller system. This is due to the fact that STOL operations require optimized power generation from the propellers. Moreover, this aircraft will be required to fly over long distances: – a fact that is implied by the number of engines that it has. The adjustable pitch of the propellers will make it possible for the pilot to tilt them in such a way that reduces drag to the fullest which will enable them to develop the capability of developing more thrust and lift necessary for taking off from a short runway. The pitch for which an aircraft’s propeller is mounted is either designed to accommodate cruise speeds or other STOL operations (University of Southampton, 2018). Therefore, the fact that the propeller on this system is adjustable will give the pilot the opportunity to perform STOL but still find pitch optimizations while cruising over long distances for which the aircraft is most probably designed to accomplish.

Image of turbo-prop engine. Obtained from Glen center, NASA

Propellers are usually mounted in or on the engine system and are expected to be positioned as close to the fuselage as is possible. As the propellers develop thrust at their front surfaces, being close to the airframes will ensure that as much wing surface area as possible is available in order to develop lift much faster and more efficiently without affecting the wing’s design dynamics(Airlines.net, 2002). Moreover, the propellers are expected to send a thrust of air over the wings for extra lift. Therefore, the fact that the aircraft will be cruising for 420 knots for most of the distance will mean that there will be enough lift from the airflow hence further warranting the position of the engines being near the fuselage.

It is desirable to mount as many propellers as possible per engine shaft. These could be more than four. Although this design reduces the general efficiency of each propeller, it makes it possible for propellers tips to rotate just below the speed of sound (Mach 1). This will make the aircraft less noisy which is a general environmental concern especially in the jungles where it could disturb the existing wildlife diversity. In addition, more propellers per shaft will also make the control surfaces more maneuverable and responsive at lower speeds.

Flying aircraft in extreme climatic conditions such as dry deserts and cold arctic regions of the world presents a major expectation in the design of the plane’s cooling system. Firstly, it must be able to accommodate overheating problems rampant in desert regions while at the same time avoiding the freezing of propeller systems in the arctic regions while the craft has stayed on the ground for elongated periods of time. Therefore, it will be expected that each engine incorporates a hybrid cooling system that will make it possible for the propeller system to be cooled by either water in hot conditions or air in the arctic regions. Ice is likely to form around the engine regions while the aircraft is grounded in the arctic regions (Technische Universitat Darmstadt, 2016). Therefore, it would be necessary for the engine and propeller compartments to be designed in such a way that accommodates this factor.

Atmospheric pressures in desert and arctic regions are markedly different which create a very important consideration for designing propeller systems. The hot air in deserts is mostly characterized by low pressure while the arctic regions have relatively higher pressures. This affects the amount of air speed above the wings that is required to generate a lift for take-off. This means that the aircraft’s propeller system should yield enough lifting power to offset the drag experienced on the propellers which might need to have greater pitches in order to perform a STOLL operation in extreme and rugged conditions (NASA, 1997). In addition, the propellers should be able to accommodate reverse thrusts which will serve as brakes on landing in the arctic. This is especially true given the fact that the already short runway might be snowy hence the need to apply extra breaking via the propellers.

 

 

Image obtained from Scriebel.com

Question 3: Analysis of design features and propeller theory expected on a propeller fitted to a single engine tail wheel fighter aircraft developing less than 100 hp compared to a modern light aircraft with tricycle undercarriage.

It is important that the various propeller theories are applied in designing systems that are either focused on blade element or momentum of the forces acting on the propeller per unit time in order to create lift for flight. It would be expected that the First Word War fighters are fitted with non-adjustable propeller pitches. This could partly be attributed to the fact that the warring countries needed to produce a very large quantity of aircrafts which were often destroyed just as fast as they were being produced from the factory lines hence the need for fast advancements such as developing the B-17 bomber (ethw.org, 2015) which scrapped any need to fit them with the relatively expensive pitch adjustable propellers. However, the same will not be expected in a modern small fighter aircraft. There is much more competition from commercial aircraft manufacturers such as Cessna who have mastered the art of producing such low cost effective aircraft. Due to this kind of competition, it has become necessary to optimize the functionalities of the individual planes and this will include fitting them with as much control for the pilot as possible for the pilot’s control systems.

Small fighter aircrafts are usually handled by inexperienced pilot trainees. During the First World War, it was common for war time pilots to sacrifice their lives by flying right into other aircraft during combat missions. This necessitated the need for a propeller system that could maintain a steady course as much as possible, and indeed maintaining a steady course is something that is still admired in today’s aviation industry. However, the extensive use of smaller airplanes in training activities has necessitated the need to incorporate as much control and automatic systems as possible in order to ensure that the students can complete their flying classes without a major incident. Among others, the modern propeller systems are designed in such a way that they can even recover from a stall which can save a panicked and shocked pilot trainee- something that could not be possible with the First World War aircrafts.

First World War fighters had a shorter tail wheel which gave the wings an increased angle of attack against the air while the plane is taking off. This is different from the modern tricycle undercarriage aircrafts which are almost lateral to the ground surface while on the ground. However, the fact that the wheels of the old fighters could never be retracted meant that any propeller advantage gained over the modern design was reversed as soon as the aircraft took into the sky (Century of Flight, 2018). The modern light aircrafts could tap into this advantage if they got their undercarriage slightly elongated. This would in turn provide a natural increased angle of attack for the mass of air released over the surface of the wings by the rotating propeller. Consequently, this kind of design would be able to server STOL operations much better and efficiently. However, the general aesthetic design of this system would not be as appealing and this could reduce the market share of a company trying out such an innovation.

Blade element theory would be an important consideration in a modern lightweight aircraft whereas First World War fighter aircrafts might not incorporate this principle. The blade element theory utilizes the principles behind the functioning of a normal wing, by increasing the curvature at the front more than the one at the back side (Aerodynamics for Students, 2016). This, in effect, creates a kind of lift towards the front which is in essence the generated thrust for the aircraft. Consequently, the modern light aircraft is capable of deriving more thrust from the action of the propeller. This means that a smaller engine is capable of developing as much power as did a larger engine fitted on a fighter during World War I.

 

Conclusion

Aircrafts with a single piston have been around since 1903 and are likely to stay around for quite some time. The single piston racing aircraft from the 1930s basically have the same airframes and engine technologies being used in the modern Unlimited Class race. The modern racing airplanes are however much more modified than their old counterparts. Some of these modifications include the freedom of the ground crew to use fuels of their choices, tweaking the propeller rotation systems and reductions gears and redesigning the wing control surfaces among others. These changes have ensured that each racing pilot gets as much edge as possible over other competitors and harnessing higher speeds and more resilience on the g force being exerted on the aircraft.

A turbo-prop four engine aircraft used in STOL operations has a set of unique propeller requirements that could enable it perform its job optimally. Among others, the pitch of the propellers will need to be adjustable so that the pilot can continuously optimize the performance of the propellers while flying under different air speeds and conditions. These are primarily dictated by speed requirements while taking off and those that come into the picture while the plane is cruising. The propeller theory is a comprehensive mathematical design consideration which is used in propellers. This theory makes a designation for designing propellers based on the moment created by the blast of air pushed by the propellers per unit time. The first two approaches are the most commonly design approaches while the vortex theory is rather mathematically complex hence does not receive as much attention by designers. General expectations dictate that modern small aircrafts make a combination of the lessons learnt over the period of aviation design and as such make flight optimizations as possible in order to harness the best flying experiences from the propeller system.

 

 

 

 

 

 

 

 

References

Aerodynamics for Students, 2016. Blade Element Theory for Propellers. [Online] Available at:            http://s6.aeromech.usyd.edu.au/aerodynamics/index.php/sample-page/propulsion/blade      element-propeller-theory/ [Accessed January 2018].

Aerospace.org, 2015. Helicopter Rotation Conventions. [Online] Available at:            http://www.aerospaceweb.org/question/helicopters/q0212b.shtml     [Accessed 28 January 2018].

Ahlstrom, E., 2000. The Design of an Unlimted Class Reno Air Racer. [Online] Available at:         aero-comlab.stanford.edu/Papers/AIAA-2000-4341-839.pdf [Accessed 30 January 2018].

Airlines.net, 2002. Under Wing Engines Vs Tail Mounted Engines. [Online] Available at:            http://www.airliners.net/forum/viewtopic.php?t=138213      [Accessed January 2018].

Century of Flight, 2018. Development of Aviation Technology. [Online]      Available at:    http://www.century-of            flight.net/Aviation%20history/evolution%20of%20technology/Variable      Pitch%20Propellers.htm            [Accessed January 2018].

Daniel Hallman, 2011. The Tuskegee Airmen and the “Never Lost a Bomber” Myth. [Online]         Available at: http://www.redtail.org/wp-content/uploads/2013/03/The-Tuskegee-Airmen and-the-Never-Lost-a-Bomber-Myth.pdf            [Accessed 30 January 2018].

ethw.org, 2015. World War II Aircrat. [Online]         Available at:    http://ethw.org/World_War_II_Aircraft            [Accessed January 2018].

Hassel, P., 2012. A History of Development of the Variablle Pitch Propeller. [Online] Available     at: hamburg.de/pers/Scholz/dglr/hh/text_2012_04_26_VariablePitchPropellor.pdf       [Accessed 30 January 2018].

Lawless, R. & Shaheen, T., 1988. Airplanes and Airports: The Subtle Skill of Japanese      Protectionism. SAIS Review, pp. 101-120.

Massachussets Institute of Technology, 2017. Aluminium as a Fues. [Online] Available at:            https://www.ll.mit.edu/publications/technotes/TechNote_AIH20_Fuel.pdf [Accessed        January 2018].

NASA, 1997. Boundary Layer Control, STOL, V/STOL Aircraft Research. [Online]           Available at: https://history.nasa.gov/SP-3300/ch8.htm [Accessed January 2018].

Technische Universitat Darmstadt, 2016. What causes ice formation on aircrafts during flight?.     [Online] Available at: https://phys.org/news/2016-01-ice-formation-aircrafts-flight.html            [Accessed January 2018].

University of Southampton, 2018. Curtis-Wright: Greatness and Decline (review). [Online]           Available at:            https://www.southampton.ac.uk/~jps7/Aircraft%20Design%20Resources/aerodynamics    Bristol%20University%20Breguet%20range%20eqn.pdf        [Accessed January 2018].