The increasing trend of carrying babies in aircraft raises the question of their safety. The National Transportation Safety Board (NTSB) states that all occupants should be restrained during takeoff, landing, and turbulent conditions and that all infants and small children should be restrained in an approved child restraint system appropriate to their height and weight. The present child seats are primarily developed for automotive applications and not tested for aerospace applications; therefore, there is a need to test these child restraint systems for aerospace test conditions. Also, the cost of actual testing and the secrecy maintained by manufacturers make research process difficult and increase the importance of computer simulations. The need for validated computer models is imperative. The 12-month-old and 3-year-old child seats used in this research have been approved for use in automobiles but not in aircraft. This research attempts to develop and validate a child restraint seat model for aerospace application. Two types of child restraint seat models - 12-month-old and 3-year-old child seat models were developed and validated using the computational tool MADYMO. The surface models of these two types of seat were exported in IGS format and meshed using Hypermesh. The meshed model was then defined as a facet in MADYMO. These models were validated for the type II dynamic test condition specified according to FAA regulations. Validation was carried out by comparing the kinematics in the simulations and the actual sled tests. To ensure validity, a comparison of various acceleration profiles and force/moments experienced by the occupant under test conditions were compared. Furthermore, the injury levels sustained by the occupant in the actual sled tests and the simulations were compared. Thus, the seat models were validated for their practical applications. These simulated models can help in future research on child safety and to generate guidelines for child restraint use in aircraft. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering / "December 2006."

Operators of mobile construction equipment (e.g., bulldozers, scrapers, etc.) often opt to descend out of the cabin in an irregular fashion without using proper egress methods, despite being trained on proper egress methods. The main objective of this research was to quantify and compare the effect of arm posture, landing style, and descent height on ground reaction forces, and acceleration at the ankle and knee by performing a laboratory study. Fifteen male subjects descended from three different descent heights (38.1, 50.8, and 63.5cm) using three different arm postures (arms to the side, arms front, and arms crossed) and landing on both legs at the same time, right leg first, and left leg first. The results demonstrated that with the increase in descent heights, the ground reaction forces, and accelerations at the ankle and knee increased. Landing with the arms out stretched horizontally in front of the body (arms front) resulted in higher ground reaction forces, peak resultant acceleration at the knee, and higher transmissibility between the ankle and the knee compared to the arms hanging to the side of the body. Although having the arms out front when landing may slightly reduce impact forces, this posture may help in maintaining balance upon landing. Landing with “both legs at same time” increased the GRF, whereas landing on one leg first followed by the other leg seemed to distribute the landing force over a longer period of time. Landing on one or two legs at the heights tested in this study resulted in ground reaction forces lower than injury threshold values for the ankle from previous research. However, descending from higher heights may result in impact forces approaching or exceeding injury threshold levels. Results from this study on the effect of arm posture and landing style may be helpful for training OE on egress at lower level heights, however, engineering controls may be needed at higher egress heights. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Industrial and Manufacturing Engineering / "December 2006."

Head Injury is one of the main reasons causing fatalities in air crashes. In the year 2005, of the total 3448 accidents reported in U.S. general and civil aviation, 655 have been fatal with a total of 1150 on-board fatalities. Head Injury being the most important component contributing to these statistics. One of the main obstructions which causes head impacts are the bulkheads dividing the cabin interiors. Bulkheads in an aircraft or a ship are usually the partitions mounted using the seat tracks and upper mountings that divide different classes or sections of an aircraft. But the actual function of the Bulkhead is to provide structural stability to the aircraft or the ship. When installed by the aircraft door, it protects passengers against the cold winds blowing from the airfield. The passengers sitting on the first row behind the bulkhead in the aircraft are less than three feet away from the bulkhead. Hence in the event of an air crash or an emergency landing the front row passengers seated directly behind bulkheads or cabin class dividers have the tendency to have a head and upper torso impact with the bulkhead making it important to study this criteria in order to reduce the HIC value or the Head Injury Criteria. There are other obstructions in the head paths during a crash inside the cabin interiors of an aircraft. These may cause severe head injuries and in many cases can even cause fatalities. A comprehensive study of the head path can prevent these injuries. This thesis presents a parametric study conducted on the head paths and head trajectories during a crash using Federal Aviation Regulations Part 25 and Part 23. This thesis also presents a parametric study of the properties of the bulkhead, the seat belt, the friction and the seat pitch, and how its variation affects the HIC (Head Injury Criteria) value and the trajectory of the head paths. The attempt is to find the ideal set of properties so as to minimize the HIC value. For example the stiffness of the bulkhead directly affects the structural stability of the aircraft. The more stiff the bulkhead the more strength it imparts to the fuselage and vice versa. But as the bulkhead used gets more stiff the higher is the corresponding value of HIC. The attempt of this experiment is to arrive at the best possible stiffness so as to avoid human fatalities at the same time impart the highest structural stability to the aircraft fuselage. For this purpose, front facing impact tests are simulated using S2 50th percentile Hybrid II human dummy model with a regular two point restraint system as is common in aircraft seating systems. Tests are conducted for a single seated occupant. Sets of parametric studies are conducted by varying the stiffness of the bulkhead, the coefficient of friction between the human dummy and the seat pan & backrest, the seat belt elongation properties and the seat pitch, so as to find the best, most safe combination of material properties for the an allowable HIC value and maximum structural stability. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering / "December 2006."

This study explored the relationship of epistemological beliefs, academic self-efficacy, and passage comprehension. Seventy-five community college students were asked to complete a series of in-class questionnaires, these students were asked to be as honest as possible to enhance future teaching styles. The final sample consisted of fifty three students. Nothing of statically significance was found. Student participation and cooperation are in question, as well as the psychometricity of the measures themselves. Thus, the results are inconclusive and do not give support for the hypotheses. It is advised for future research that the sample size be enlarged, a longer reading passage be selected and a other measures be utilized. / Thesis (M.Ed.)--Wichita State University, College of Education, Dept. of Counseling, Educational and School Psychology. / "December 2006."

Adhesively bonded composite joints are widely used in modern lightweight flight and space vehicle structures and will be widely used in the next generation aircrafts such as Unmanned Aerial Vehicles (UAV) and Joint Strike Fighters (JSF). Designing of adhesively bonded composite joints is a challenging task as the characteristics of the composite laminate adherends have an effect on their performance. Wide use of composite materials is attributed to their superior properties such as high specific stiffness, excellent fatigue properties as well as resistance to environmental conditions. Although they possess such superior properties, their relatively low through thickness strength and susceptibility to impact have a significant concernpreventing designer from using in areas which are prone to impact damage. In this experimental study, impact testing was done on adhesively bonded composite laminates. Hysol EA 9394 was the adhesive used for bonding the composite laminates. Glass/Epoxy, Carbon Plain Weave/Epoxy and Carbon Unitape/Epoxy were the composite laminate adherends used for the formation of the lap joint. Quasi-isotropic laypup sequence was used for manufacture of the composite adherends. Lap joints formed using the above said adherends were impacted at the center of the joint using an Instron Dynatup drop tower with impactors of different diameters as well as with different energy levels. The impacted specimens were then non-destructively inspected using through transmission ultrasonic C-scan. Residual indendation on the impacted specimen is also recorded. Impact force, total energy absorbed, duration of impact and impactor displacement were the important parameters which were used to quantify impact response of the adhesively bonded composite joints. In addition to the above said parameters, damage area obtained from through transmission ultrasonic C-scanning was also used to quantify the impact response of the adhesively bonded composite joints. Residual indentation measurement combining with visual inspection was made use for preliminary damage detection. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering / "December 2006."

Unmanned aerial vehicles are high in demand for various purposes such as surveillance and reconnaissance in military applications. They are also widely used for civilian applications in fire monitoring and analysis, coffee harvest optimization, irrigation, crop management and other applications. Damage to UAVs is common due to the absence of an onboard pilot. One of the steps involved in reducing damage to UAVs is protecting the rotors from damage during collision with obstacles. In this thesis the design and development of a protective shroud for a quadrotor vehicle which will enable it to continue flight even after collisions with obstacles has been achieved .The shroud will protect the rotors from any kind of damage during collisions with obstacles during flight. Work has been done on the development of Differential Global Positioning System for position control of the quadrotor vehicle. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering / "December 2006."

Osteoarthritis is a common type of arthritis that breaks down the joint tissue, known as cartilage. This causes the bones to rub against each other, causing pain and loss of movement especially in weight-bearing joints in the knees, hips, feet and the back. In recent years, synovial fluid therapy is often used in patients with Osteoarthritis, where the fluid is directly injected into the tissue which acts as a lubricant in the joint. The fluid is based on Hyaluronan (HA), a pure solution of sodium hyaluronate and is a natural constituent of the human body. This study deals with the simulation and analysis of the Fluid Therapy and an aim to optimize the procedure as a function of characteristics and also disease stage. The tissue or cartilage has been modeled as biphasic and the simulation has been done using Fluid-Structure interaction using Sysnoise, commercially available FEM software. Different case studies related to cartilage damage have been analyzed and the results have been compared with the actual therapeutic procedure of fluid therapy. The results are provided in terms of the fluid velocity that helps the fluid to void the space inside the cartilage or the synovial joint. During actual fluid therapy, the fluid is expected to void between a period of 7 – 14 days, which is why the injections are give either weekly or biweekly. Results show that few patients, suffering from arthritis, can experience relief for a period of up to six months with the help of fluid therapy, with appropriate quantity of fluid and the concentration of HA in the fluid among other conditions. The present work provides an opportunity to optimize the fluid therapy procedure based on parameters, such as fluid volume and its thermophysical properties. Results from the study indicate that treatment can be custom designed by considering the concentration of HA in the synovial fluid injection, its viscosity, the weight and condition of the patient and the stage of the disease. With fluid therapy being considered increasingly, optimization procedure would be of valuable medical help and of substantial economic benefit to patients. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering / "December 2006."

In many practical manufacturing environments, setups consume a significant amount of industrial resources. Therefore, reducing setups in a non-identical parallel machine environment will significantly enhance a company's performance level. In this thesis, the problem of minimizing total completion time with load balancing and sequence-dependent setups in a non-identical parallel machine environment was studied. A mathematical model for minimizing total completion time with a workload-balancing constraint is presented. Since this problem is an NP-hard problem, some simple heuristics and a genetic algorithm were developed for efficient scheduling of resources. Both were tested on random data. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Industrial and Manufacturing Engineering / "December 2006."

This thesis involves proposing an efficient algorithm, which takes into consideration the NALU (Network abstraction Layer Unit) and tries to improve the H.264 codec performance over a network. Along with the bandwidth instabilities in the Internet and other issues like the packet drop cause the video frames to be dropped, which makes the video, appear distorted. The main idea behind the algorithm is to vary the bitrate by varying the Quantization parameter, both of which are stored in the reference table. The reference table is calculated based on the analysis of the sequences of different video clips. By changing the bitrate based on the bandwidth available the codec performs better and produces good results of (Signal to Noise Ratio)SNR. The research is based on the development of the reference table which when referred helps to change the quantization parameter of the codec for coding a Group of Frames in a video by periodically checking the network statistics. At the cost of reduction in the resolution due to the network conditions the video frame drop is avoided which helps improve the video quality at the decoder.. The entire simulations for this research were carried out using the JM Reference Software H.264 Encoder and decoder Version JM 10.2. Packet drop was simulated by dropping the individual NAL units from the video stream. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical and Computer Engineering / "December 2006."

The purpose of this study is to determine the effect of dents on the fatigue properties of 0.04 inch thick 2024-T3 bare aluminum sheet, which is the most widely used material for aircraft skin. The study is divided into two parts. The first part (Part I) is a study on the effect of dents on the fatigue life of the material, while the second part (Part II) is a study on the effect of dents on crack growth in the material. The test specimens were either pristine (no dents), dented or reworked. For Part I, the dented and reworked specimens were divided into two groups, depending on the dent depth ranges. The dent depths for each of these two groups ranged from 0.030” to 0.0335” and 0.0605” to 0.065”. Dents were produced with a drop tower having a 0.5 inch spherical hardened steel indenter head. The fatigue life of the material in these three conditions was determined experimentally. Constant amplitude fatigue tests were conducted according to ASTM-466 with a single stress level and a single frequency for the fatigue cycle. The results were then compared to determine the effect of dents and the reworking of dents on the fatigue life of the material. Results of the study indicate that the fatigue life of a dented specimen is significantly less than that of the pristine and the reworked specimens. The study also showed that the fatigue life decreases as the dent depth increases in the dented specimens. Statistical analysis of the results showed that there is no significant difference in the fatigue life between the reworked population and the pristine population of specimens, while reworking considerably improves the fatigue life of the dented material. For Part II, the specimens are again either pristine dented or reworked. The edgecracked pin-loaded specimens of 8” in width were tested at constant amplitude loading with a stress ratio of 0.2 producing stable crack growth of close to 4 inches completely through two dents on the crack line. Dents were produced the same as described for Part I. Dent depths ranged from 0.03” to 0.0325” measured on the convex side of the specimen. A starter notch of 0.3” was produced at the edge of the specimen with a jeweler’s saw blade. The specimen was fatigue loaded under constant amplitude loading to produce an initial crack length of 0.37” t which time readings of crack length vs. cycles began. The same constant amplitude cyclic loading used to produce the initial crack length was used during the testing. The crack lengths were measured with an optical microscope at 160X magnification. Nine specimens were tested including three replications for each of the three conditions. Crack growth data is given in both tabular and graphical form for all specimens. Crack growth rate data is also presented in graphical form. The overall crack growth in the dented specimens was significantly greater than in the pristine specimens. It was also, on the average, faster in the reworked specimens however, reworking, in general, did not recapture the life displayed by the pristine specimens. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering / "December 2006."