The demonization of single parents by media and government sources has been a persistent problem in our society. In order to examine the validity of the claims made against single parents, this study examines the relationship between household structure and composite reading and math test scores. Secondary data analysis was used from the Educational Longitudinal Survey of 2002 (ELS: 2002) of 10,945 10th grade students with a composite model consisting of: student role performance (SRP), schools, and families. Univariate, bivariate, and multivariate analysis are used to examine the independent effects on test scores. Mean composite test scores show a statistically significant difference in the test scores of students from single parent families (48.17) and dual parent families (51.88). The examination of the unique variance in test scores for each model segment shows student role performance factors explain more of the “unshared” variance in test scores than the other model segment. These results suggest that the blame of student outcomes on parent structure is explained by factors such as socioeconomic status within student role performance than the actual parental structure. / Thesis (M.A.) - Wichita State University, College of Liberal Arts and Science, Dept. of Sociology

The follicles in a human ovary gradually decline in number during infancy, adolescence and the reproductive years. However, during the perimenopausal period there is a more rapid decline in follicles. Older women have fewer granulosa cells in their follicles than younger women. The older ovary is less responsive to gonadotropins, especially FSH. It is hypothesized that age-related, decreased responsiveness to FSH is due to decreased FSH-receptor (FSH-R) levels and/or alternate splicing of FSH-R mRNA resulting in defective (impaired) receptors. Human ovarian follicles of sizes ranging from 3 to 7 mm in diameter from 26-46 year-old women were isolated, snap frozen and stored at -80°C. RNA was isolated and real time PCR performed to measure the FSH-R mRNA levels in the follicles. Linear regression analysis was performed on FSH-R mRNA levels within follicle size categories as a function of age. The regression analysis was found to be non significant. Therefore, we reject the hypothesis, which stated that FSH-R mRNA levels within follicles decrease as the ovary ages. To analyze alternate splicing of FSH-R mRNA, two oligonucleotide primer sets were designed. RT-PCR of total RNA from follicles of 26-46 year-old women was performed. PCR products were sequenced to determine the degree of homology for the FSH-R with the human FSH-R variant 1 published in Gene bank. There was 99.7% sequence homology between the FSH-R PCR amplimers and human FSH-R variant 1. This suggests that impaired ovarian response is not due to alternate splicing of the FSH-R mRNA in older women, and is inconsistent with the hypothesis that alternate splicing of FSH-R mRNA is the cause for decreased response to FSH in an aging human ovary. Accordingly, decreased response may be due to other factors, perhaps FSH/FSH-R post receptor signaling mechanisms. / Wichita State University, College of Liberal Arts and Sciences, Dept. of Biological Sciences / Includes bibliographic references (leaves 37-44)

Mass transportation systems and specifically bus systems are a key element of the national transportation network. Buses are one of the safest forms of transportation. Nonetheless, bus crashes resulting in occupant injuries and fatalities do occur. Each year, more than 5,800 children die, nearly 120,000 are permanently disabled, and more than 14 million are hurt seriously enough to require emergency medical care due to unintentional injury. Therefore, effort is needed to improve the performance of bus interior and structure. Child Safety is a continuing effort to improve the safety of children in mass transit buses. This project provides an overview of the implementation of two types of attachment systems Child Restraint Systems (CRS) in a mass transit buses. A series of sled tests were conducted in order to evaluate the performance of the Child Restraint Systems for typical frontal, side and rear crash scenarios. The results of the test indicate that the implementation of ISOFIX or LATCH attachments in transit bus seats mitigates the risk of severe injuries to the 12 month-old, and 3 year-old occupants; while not increasing the risk of severe injuries due to CRS interactions to other unrestraint adult passengers. In the next phase of this research, results from these sled tests were validated using the multibody analysis tool MADYMO to evaluate the performance of child safety in mass transit buses using the Federal Motor Vehicle Safety Standards (FMVSS 208) injury criteria. The Kinematics of sled tests are closely matching with that of simulations. Injury values for sled tests and simulations are well below injury criteria. The results from this study show the 20 % variation in injury signals. This study concludes that interior for mass transit bus with child seats and restraint can be utilized in mass transit buses to improve the safety performance of children. / Wichita State University, College of Engineering, Dept. of Mechanical Engineering / Includes bibliographic references (leaves 83-86)

The shape of the temporal bone of the adult human cranium, specifically the mastoid region, is documented widely in past literature as a measure of sexual dimorphism within and among human populations. Yet, past research focuses primarily on the qualitative assessment of the size of the mastoid region as it varies between males and females. This thesis explores both standard qualitative and standard and nonstandard quantitative measures of variation, in both size and shape, of the inferiorly projecting cone-shaped process of the temporal known as the mastoid process. A set of eight measurements, two of which use five non-metric scores, are recorded for 100 male and 100 female adult White crania from the Hamann-Todd Osteological Collection at the Cleveland Museum of Natural History. It is hypothesized that a quantitative approach will either exceed or provide greater consistency in identification than the qualitative characterization of the mastoid region, as it is used almost exclusively in current practice. Descriptive statistics demonstrate patterns of sexual dimorphism in the mastoid region and univariate statistics reveal significant differences between the measurements among males and females. A nonstandard measure of the height of the mastoid process, mastoid radius, is tested against the standard measurement, mastoid height. Descriptive statistics reveal a strong correlation between the two measurements. Univariate statistics show significant differences between the two measurements and variances around the mean suggest that the mastoid radius provides greater consistency as a measure of size than does the standard mastoid height measurement. The results from this study indicate that quantitative analysis of the mastoid process correctly classifies more individuals than qualitative scoring. Further, scoring the size of the supramastoid crest produces a greater percentage of correct sex identification than the qualitative scoring the overall size of the mastoid process. / Wichita State University, College of Liberal Arts and Science, Dept. of Anthropology / Includes bibliographic references (leaves 43-46)

Passenger vehicles in today’s world are more crashworthy than they used to be. Significant improvements have been done in the recent years to improve protection for occupants in the passenger vehicle; most of it was done in frontal crashes and only a small amount of improvement has been observed in side impact crashes. Thus, making it necessary, to do significant research on side impact crashes. Side impact standard FMVSS 214 was established to be used as a base for studying injury parameters during side impacts. But, this standard does not take into account the severities of Neck injury. Neck injuries, used to associate with front and rear side crashes can be life altering. Neck injuries are even given lowest ratings on the Abbreviated Injury Scale (AIS) 1. Recent studies show the importance of neck injury during side impacts, leading to need for immediate need to study the effect of neck injuries on occupants in passenger vehicles. In this study, to address the above concern effort has been made to improve neck injury protection during side impacts, using FMVSS 214 standard as the basis to study the effect of airbag on restraint system in improving occupant protection from neck injuries. Two different dummy models US-DoT SID (according to FMVSS 214 standard) and Hybrid III 50% dummy have been used for the study, and the results show improvement in Neck Injury Criterion (NIC) commonly used to assess neck injuries along with improvement in Head injury criterion (HIC) commonly used to evaluate head injuries with the use of airbag on restraint system. / Wichita State University, College of Engineering, Dept. of Mechanical Engineering / Includes bibliographic references (leaves 93-95)

An exploratory analysis has been performed on a small number of flights of the P-2V aircraft operating in the firefighting mode as opposed to the anti-submarine and search-and-rescue operations for which it was designed. The data consists of 38 flights from the 2005 and 2007 fire seasons, for the same aircraft, totaling approximately 35 flight hours. Each flight has been divided into two ground and five flight phases and analyzed separately, with emphasis on the loads and atmospheric turbulence experienced by the aircraft. Some aircraft usage data has also been extracted and shown. Aircraft usage information in terms of operating altitudes and airspeeds, as well as maximum loads and V-n diagrams, have been examined for each flight phase. Flight loads for each phase have been separated into gusts and maneuvers using the “Two-Second Rule” and have been normalized per 1000 hours and per nautical mile. Atmospheric gust velocities for each phase have also been extracted and presented in both forms. Finally, the resultant gust and maneuver flight loads have been compared with standard design gust loads and Mil-8866 maneuver loads. A number of general trends have been observed by comparing the phases before and after the release of retardant. It has been shown that the release of retardant weight would significantly decrease wing loading and thus both the cruise speed and response to atmospheric turbulence. This has been demonstrated as being caused by weight by showing the levels of atmospheric turbulence to be the same before and after the drop. The effect of the changing weight on loads has also been examined in detail. The decrease in the weight of the aircraft during the taxi after the drop has been shown to increase the frequency of all loads as well as their severity compared to taxi loads prior to the drop. A similar effect has been highlighted for the cruise phases before and after the drop. Maneuver loads while delivering the retardant have been shown to be the highest in both sets of data. However, a significant part of the increased vertical acceleration is believed to be due to the change of mass while releasing the retardant and not due to maneuvering of the aircraft as is commonly believed to be. The derived and continuous gust velocities are shown not to be remarkably different before and after the release of retardant. The results suggest that the atmospheric turbulence is largely the same before and after the drop with a trend of lower severity at higher altitudes. Comparisons of the results with the military standards for design gust and maneuver loads are provided and show that lower-magnitude accelerations can be as much as 10 times more frequent than design conditions predicted. This is not deemed to pose a threat to exceeding the limit load factor for the airframe, but it can lead to a lower than expected fatigue life for the aircraft. These results indicate that these aircraft are operated in environments different from those for which they were designed. Therefore, maintenance schedules developed for their naval missions may not be applicable for their operation as firefighters. / Wichita State University, College of Engineering, Dept. of Aerospace Engineering

The goals of this project were to determine and document the effects of sealants and surface treatments have on the ultimate strength, fatigue life, and corrosion resistance of swept Friction Stir Spot Welded (FSSW) joints. One sealant, the PRC-DeSoto PR-1432 GP and several surface treatments were examined. The surface treatments attempted were AlClad, Chromic Acid Anodization on bare sheets, and Alodine chemical conversion coating on bare sheets. Bare sheets without a surface treatment were also evaluated to establish a baseline comparison. Ultimate lap shear testing was based on the unguided NASM 1312-4 2-spot weld coupon configuration and the guided NASM 1312-21 4-spot weld coupon configuration. Results indicated that the sealants and surface treatments decreased the joint strength of the individual spot welded joints a relatively small amount compared to the bare material strength. However, the sealant’s adhesive properties can potentially compensate for this loss if there is sufficient sealant coverage. The guided NASM 1312-21 4-spot weld coupon configuration was used for fatigue testing. Uniform amplitude fatigue tests were conducted with a variety of load levels to generate a load-life curve. The sealants and surface treatment seemed to have no effect on fatigue life at medium to low fatigue load levels. However, at high fatigue load levels, the sealants and surface treatments were slightly detrimental. The fatigue lives of the swept FSSW coupons was less than those of the NAS 1097 AD4 riveted coupons at the medium to low loads. However, the swept FSSW coupons were not optimized for fatigue and may improve under such conditions. The results of the corrosion testing indicated that the integrity of the sealant was not compromised by the swept FSSW. Generally, the surface treatments were not affected by the FSSW operation except where the tools displaced the surface and on the anvil side of the coupon in the heat affected zone. Since these areas are more vulnerable to corrosion, some protection should be added after welding. In general, the results of this project show that swept FSSW can successfully weld through sealants and surface treatments with only a minimum loss of the ultimate strength or fatigue life of the joint. The FSSW operation can be performed while maintaining most of the corrosion resistance. / Wichita State University, College of Engineering, Dept. of Aerospace Engineering / Includes bibliographic references (leaves 50-54)

Data obtained from digital flight data recorders installed on a fleet of 27 Beech 1900Ds are used to assess the actual operational environment of propellers on commuter aircraft. The data consists of 910 complete flights and 589 flight hours. Aircraft operations have been separated into three ground operations categories and five flight phases. Parameters that pertain to the propellers are emphasized. Overall aircraft and subsystem usage is also considered to establish the commuter airline flight profile. Overall aircraft usage includes information on flight durations and time within each flight phase, time at various airspeeds and engine torque levels, and flap operations. Flights of commuter aircraft are shown to be of short duration, with the cruise phase accounting for the majority of airborne time. Ground phases highlight the operation of the propellers within prohibited shaft speed ranges. A noticeable length of time is shown to have been spent within these restricted ranges. The usage of reverse thrust during landing rollouts and ground operations is also considered. Reversals upon landing accounted for less than half of the total number of reverse cycles. The short duration takeoff rotation is shown to impose the most severe operating conditions on the propellers. Aerodynamic parameters indicate large inflow angles into the propeller disk, resulting in the most severe vibratory loads. Engine torque, propeller shaft speed, and airspeed are all considered as contributing factors to the large vibratory loads the propellers experience at takeoff rotation. Information pertaining to the in flight engine and propeller usage is also given, and shows no abnormal usage of these components. Cumulative frequency of occurrence of angle of attack for each of the five flight phases has been normalized per 1000 hours and per nautical mile. Each flight phase is shown to produce a unique pattern of frequency of occurrence of the angle of attack, driven by the associated airspeeds. Another aerodynamic parameter considered while in flight is the upwash angle. Upwash angle has been derived for a variety of aircraft weights and airspeeds. This parameter is shown to have a significant influence on the propeller inflow angle, especially at high aircraft weight and low airspeed conditions. The change in inflow angle due to gusts has also been extracted and normalized per 1000 hours and per nautical mile. This data is given in the form of plots of cumulative frequency of occurrence for each flight phase and altitude. Increasing altitude shows a significant reduction in the frequency and magnitude of variations in angle of attack caused by gusts. The information is presented in statistical formats that could enable the FAA, the propeller manufacturer, and the airline to better understand and control those factors that influence the structural integrity of these components. / Wichita State University, College of Engineering, Dept. of Aerospace Engineering / Includes bibliographic references (leaves 82-84)

With an ever growing fleet of commercial airplanes utilizing composite structures, it is increasingly important to develop cost-effective and robust repair procedures. Issues invariably occur during on-site repair which casts doubt on the structural suitability of the part. This makes the ability to quantify the relationship between dwell temperature, cure state, and mechanical properties extremely important. Curing temperatures play a vital role in the difficulty of repairs. Lower cure temperatures mean lower cost, less possibility of damage to surrounding material, and therefore, the potential for a more robust repair scheme. As such, low temperature cure materials are of great interest to the composite repair community. Current state-of-the-art says that cure must be very precise to ensure structural integrity. As such, any repair with thermocouple readings outside a very narrow band must be reworked at substantial cost. Often, when rejected repair materials are tested, they are found to be structurally sound. The search for a solution to this problem has been the motivation for this study. Rheometer testing quantifies the viscoelastic properties of the composite material as it cures. This ex-situ approach allows a very detailed and accurate view of cure state properties. These properties include glass transition temperature (Tg), gel time, vitrification time, G’ (storage modulus), G” (loss modulus), and Tan_ (G”/G’). Glass transition temperature, gel time, and G’ were used to correlate viscoelastic properties with mechanical properties. The mechanical properties of interest were short beam shear strength, compression strength, compression modulus, compressive Poisson’s ratio, tension strength, and tension modulus. Correlations were attempted for all mentioned mechanical properties. It was found that the highly resin-dominated compression and short beam shear strengths showed a strong correlation with viscoelastic properties. Both of these mechanical properties showed a very strong relationship to the nearly constant portion of the storage modulus G’ after curing is complete. Compression and short beam shear strengths showed a weaker relationship with Tg, and none of the properties considered showed good correlation with gel time. All other mechanical properties showed little or no change based on dwell temperature and, therefore, no acceptable correlation to viscoelastic properties was achieved. Mechanical properties which correlated well with the viscoelastic properties showed no statistical difference for dwell temperatures from 200°F to 260°F, and the nonresin-dominated properties showed little difference from 180°F to 260°F. This significant finding indicates that fiber-dominated properties remain constant for a wide range of cure temperatures. Resin-dominated properties remain statistically constant over a much larger cure temperature range than currently utilized by industry. / Wichita State University, College of Engineering, Dept. of Mechanical Engineering / Includes bibliographic references (leaves 89-92)

Ever since composite materials have been used in the aerospace industry, there have been problems with cutting and machining them. One of the reasons for this problem was the dearth of available tooling to machine composites. As research in composites progressed and as composites found wide application in the aerospace industry, efforts have been made to develop good and efficient tools to machine them. Nevertheless, this effort is still ongoing to develop better tools, as the problems faced during machining have not been totally eliminated. Of the different machining operations performed on composite materials, drilling is the most common. The major problems faced during the drilling of composite materials are delamination and fibers pull out. Delamination reduces the strength of the composite. Another problem that persists is the effect of excess cutting temperatures on the quality of the drilled hole. Excess cutting temperatures affect the dimensional accuracy of the drilled hole and deteriorate its surface finish. Excess cutting temperatures during drilling may melt the matrix and char the drilled hole. Research and experiments conducted on drilling of composite materials have shown that as the cutting edges of the drill bit wear out, the heat generated and the thrust force produced increases. Increase in thrust force gives rise to delamination. Also tool geometry plays a big role in producing a hole with an acceptable quality. Hence, it is important to thoroughly investigate the performance of the drill bit in terms of producing a good hole quality. The objective of this research work was to evaluate the performance of drill bits when drilling carbon-fiber composites. Drill bits were evaluated for temperature, Hole oversize, surface roughness, roundness, thrust force, torque, damage area, and tool wear. By conducting experiments using different drill bits, the drill bit performance was determined for every parameter in question. Based on the results of these experiments, it was possible to determine which drill bit performs optimally for the different parameters investigated in this research work. Also by evaluating the Hole oversize, roundness, and surface roughness, it was be possible to study the effect of speed and feed rate on these parameters. Also tool wear analysis was carried out as a part of this research work. / Wichita State University, College of Engineering, Dept. of Mechanical Engineering / Includes bibliographic references (leaves 167-169)