Recent advancements in friction stir welding (FSW) technology and pin (probe) tool design for aluminum have made FSW applications in aerospace and automotive structures quite attractive. FSW has the potential for better fit, form and function when compared to fusion welding. The aim of this research was to design, develop and fabricate a fixture to meet the requirement of a standard automotive impact test on an FSW bumper/crash-box assembly. A fusion welded bumper/crash-box design was provided to Wichita State University (WSU) by the General Motors Corporation (GM). For this case study, the bumper design was not changed, but the existing crash box was altered to satisfy two FSW assembly designs, incorporating unique lap and hybrid welds for the closeout area at each end of the bumper. Both designs use a common butt weld along a nested interface between the crash box and the bumper. The goal of this test fixture was to facilitate a dynamic vehicle test on FSW bumpers and compare the test results to that of fusion-welded bumpers. Functional use of FSW in bumper design was to be determined through this case study. Since the test fixture uses similar type welds as the bumper geometry, FSW was also incorporated into the test fixture design. Several design constraints related to vehicle testing, FSW and the University Impact Laboratory were met. Process simulation of dynamic forces on the bumper and test fixture welds, along with standard static analysis, were used for design verification. Parameter bounding and test coupons of FSW in aluminum were used to determine parent and weld material properties as well as optimum weld parameters for manufacturing the test fixture. Aluminum alloys 6063-T6, 6061-T6, 7050-T7451, concrete and structural fusion welded steel were selected for materials in the test fixture design. A linear bearing rail system was used to facilitate the gravity-fed drop tower and dynamically fed sled test functions / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.

Nonviolent mass movements have played a significant role in bringing about change in the 20th century. They stood up to the very powers that oppressed them and helped those forces see a reality they were once blind to. Their strength in numbers and moral positioning helped “the other” empathize with their plight and in some cases join their cause for change. Two such movements were the African American Civil Rights Movement of the 1960s and the first Palestinian Intifada in the 1980s. These two movements mobilized masses and transformed communities. While in many respects, they were very different; there are strands of similarity that weave through both movements. These commonalities began with a connection to nonviolence that preceded the movements themselves and proved essential foundations and building blocks for what was yet to come. Influenced by the work of Mahatma Gandhi and others in India, both African Americans and Palestinians sought guidance from the East. Of major significance, is the inspirational role African American civil rights played in influencing the Palestinian Intifada. Palestinian leaders were drawn to the success and example of black leaders who helped motivate a discontent base. Through a side-by-side comparison, the similarities are apparent; whether they are in mass demonstrations, boycotts, strikes, conversions of the other, or the struggle for education. The examination of these different elements in both movements through writings, newspaper coverage, opinion pieces, and personal accounts demonstrates just how much the 1960s black civil rights era impacted the Palestinian Intifada of the 1980s. / Thesis (M.A.)--Wichita State University, College of Liberal Arts and Sciences, Dept. of History.

This study concentrates on the relationship between the hardness of three different carbon/graphite brushes and the wear rate of the brushes and heat generated within a 400 Amp starter generator. The method being proposed was to alternate the starter generator from the starting mode and the generating mode, and run each carbon/graphite brush in the starter generator for a set time and document both wear rates and heat created. The study originated with a starter generator overheating during normal usage. The original hypothesis was that either excess carbon dust caused arcing, or the energy required to form the carbon dust was releasing too much heat, and thus the brush was too hard. The three carbon/graphite brushes chosen for this researched spanned the range of hardness for this type of material. This thesis analyzed the surfaces of the carbon/graphite brushes to correlate grooves and pitting with the frictional coefficient. An optical microscope, AFM, and SEM were used in the analysis of the surfaces. It was found that as the hardness of the brush went up, the wear rate decreased while the overall heat on the inside of the starter generator increased. From this research it is evident that the hardness of the brushes is the key factor in the excess heat in the starter generator. The energy that is expelled as heat as the carbon brush gradually wears is directly correlated with the increase of operating temperature. A harder brush will prolong the life of the brushes, but also increases the operating temperature to more than the unit is capable of handling. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.

The effect of variation in autoclave pressure, cure temperature, and vacuum-application time on porosity, hot/wet (H/W) and room temperature/dry (RT/D) short beam shear (SBS) strengths, and failure mechanisms of IM7/977-2 unidirectional prepreg was investigated. The stacking sequence for all panels was [00/902/0]4s. Fourteen cure cycles were designed to study a wide range of cure pressures, cure temperatures, and two different vacuum-application durations, including vacuum vent at recommended pressure and vacuum hold throughout the cure cycle. It was found that for panels cured at different temperatures and for panels cured at different pressures with a vacuum vent at recommended pressure, SBS strength did not vary significantly over a relatively wide range of cure temperatures and pressures. However, after a certain point, a decreasing trend in the average SBS strength for both H/W and RT/D was observed by reducing the cure temperature as well as the cure pressure. Panels with the same cure pressure and dissimilar vacuum-application durations showed different SBS strength, with higher properties associated with panels in which the vacuum was vented at the recommended pressure. For panels cured at various cure pressures and the vacuum hold throughout the cure cycles, C-scan results showed a cross-shaped high-porosity in the middle of the panels, which became larger as the cure pressure decreased. This defect is believed to cause higher variability of the SBS strength as the cure pressure is reduced. SBS strength was found to decrease with increasing void content in the test specimens. Theoretical models were compared to the experimental data of SBS strength vs. void content. Investigation of the failure mode for each panel revealed a change in both H/W and RT/D failure mechanism by lowering the cure temperature and cure pressure. However, the change was more dominant when the cure temperature was varied. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.

In an effort to increase general aviation safety, a simplified model reference adaptive control (MRAC), adapting to modeling error with only a bias neuron, is applied to a desktop simulation of the Hawker Beechcraft Corporation (HBC) CJ-144 fly-by-wire aircraft in six degrees of freedom. MRAC has been experimentally applied to military and commercial aircraft by the National Aeronautics and Space Administration and the Department of Defense. Previous research at Wichita State University has demonstrated promising results for MRAC’s application to general aviation in three degrees of freedom, both in its ability to achieve desired handling qualities and adapt to unexpected changes in aircraft dynamics. MRAC is used to control the aircraft in the nominal case and adapts to maintain control with changes in flight condition or unexpected A matrix and B matrix failures. The HBC CJ-144 aircraft is configured for decoupled flight control where the pilot commands the airspeed, flight path angle, bank angle, and side force. The controller architecture consists of an inverse controller, single bias neuron adaptive element, model follower and linear controller. A six degrees of freedom dynamic inverse controller is derived to calculate the necessary thrust and control surface deflections in the nominal flight case. An artificial neural network is trained online to correct for uncertainties in the inverse and to adapt to changes in either the flight condition or the aircraft itself. The aircraft response is shaped by a model follower and linear controller. An artificial time delay metric is used to tune the controller gains for the desired performance. The controller and aircraft are simulated in the MATLAB/Simulink environment. Time response results are presented for maneuvers in each axis as well as aircraft response to unexpected failures. In simulation, the desired aircraft response was achieved. Additionally, the controller was able to maintain stability and complete maneuvers following A and B matrix failures. This controller is designed to be flight tested on the HBC CJ-144 fly-by-wire testbed. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Aerospace Engineering.

The purpose of this study was to examine the efficacy of the token economy system in reducing physical aggression, property destruction, and disruptive talk in an adolescent diagnosed with autism spectrum disorder. The participant, age 15, met the enrollment criteria of a residential school designed to address the behavioral and academic needs of children with developmental disabilities. This study used quantitative, single subject treatment reversal design. The participant’s behavior was observed and data was collected in Phase I, Baseline, “A” (one week), Phase II, Intervention, “B” (seven weeks), and Phase III, Return to Baseline, “A” (one week). In Phase I, Intervention, “A” the variability of the frequency of targeted behaviors included: physical aggression was 0 to 10, property destruction was 0 to 6, and disruptive talk was 0 to 7. In Phase II, Intervention, “B” the variability of the frequency of targeted behaviors included: physical aggression was 0 to 8, property destruction was 0 to 5, and disruptive talk was 0 to 40. In Phase III, Return to Baseline, “A,” the variability of the frequency of targeted behaviors included: physical aggression was 0 to 9, property destruction was 0 to 2, and disruptive talk was 0 to 15. Interpretation of the results indicated instability in the variability of the frequency of all targeted behaviors, as the token economy did not serve as an effective method in modifying the behavior of the participant. / Thesis (M.Ed.)--Wichita State University, College of Education, Dept. of Curriculum & Instruction.

This study tested a method for increasing student achievement in a seventhgrade gifted classroom. Literature on underachievement supports various methods for avoiding underachievement, including developing interests, identifying heroes and utilizing adult helpers, discovering careers, creating academic and personal goals, naming short-term and long-term plans, and completing student interest projects. Renzulli Learning created a Personal Success Plan (PSP) with the intention of creating a tool to increase student achievement of students with giftedness and lower the underachievement in students. Pretest data was taken on the 23 students before the intervention of the PSP was begun. Posttest data was then taken after the intervention was completed according to the timeframe indicated by Renzulli Learning. Through observation of the data, it is evident that there is a positive correlation with utilizing the Personal Success Plan intervention 100% of the recommended time and increased academic achievement. For students who completed the intervention as recommended, academics did increase. / Thesis (M.Ed.)--Wichita State University, College of Education, Dept. of Curriculum & Instruction.

Wireless sensors are often deployed in remote areas to monitor and detect interesting events. For long-term monitoring of these events, it is necessary for sensors to have perpetual operation. Hence, they are equipped with batteries that recharge using renewable resources. The work in this thesis considered the problem of detecting changes in the state of event process (referred to as state transitions) so that the number of redundant transmissions is reduced. The objective was to maximize the number of transitions detected and transmitted under energy constraints. Two types of transitions were considered: transition transmitted immediately and transition transmitted with a delay. Transitions transmitted immediately reap the maximum reward, while late transmissions are modeled to reap a reward that decreases exponentially with the delay in transmission. The problem was formulated as a partially observable Markov decision process(POMDP), and the optimal policy (maximizes the average reward over time) was evaluated using value iteration. An approximate solution for the optimality equation was formulated, and the applicability of the approximate solution under various state space categories was discussed. Motivated by the structure of the optimal policy, a simple near-optimal policy that is asymptotically optimal was proposed. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science.

Today, most portable devices, e.g., cell phones, PDAs, and laptops are Wi-Fi capable. Users can make efficient use of these devices by running various applications, including Voice over Internet Protocol (VoIP) to make calls. Portable devices are limited in terms of battery life, and hence the energy involved in the VoIP application is of concern. This thesis, presents experimental studies on the energy consumption of the devices using IEEE 802.11 Wireless LAN for making VoIP calls. The effect of high (G.711), medium (G.729), and low (G.723) bandwidth codecs on battery life was studied. This investigation shows that the G.723 codec is the most energy efficient. There exists an energy-quality tradeoff when selecting codecs. In this thesis, an adaptive algorithm, Efficient Codec Switching Algorithm (ECSA), is proposed. The ECSA utilizes a combination of codecs to minimize energy consumption of a VoIP call while meeting user-specified quality constraints. When using a laptop, these results demonstrate a percentage improvement of 6.43% to 24.1% over currently used codec schemes. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science.

The purpose of this four-week study was to determine if the use of eReaders vs. traditional print novels in the eighth grade classroom would increase the comprehension scores, engagement, and comprehension strategy usage of struggling readers in the language arts classroom. The participants in this study consisted of twelve eighth grade students who performed at least two grade levels below on the STAR Comprehension Test. In addition to performing poorly, these students were also reluctant readers. Based on the assessments and classroom observations, the researcher attempted using eReaders to increase engagement, comprehension, and strategy usage. The researcher collected data on engagement before and during the study and had the students in the control and experimental groups work on comprehension strategies during the four-week period. Students took a STAR test at the end of the four weeks to measure comprehension gains. The results indicated significant gains in positive engagement and in comprehension strategies (words looked up and connections made) for the eReader group, while students in the print group were approaching significance in comprehension. In conclusion, the research showed that both conditions boasted positive results in various aspects of the study. While eReaders served as a tool to engage students positively during reading and to assist in the task of note taking, it did not necessarily contribute to the increase in comprehension gains. / Thesis (M.Ed.)--Wichita State University, College of Education, Dept. of Curriculum and Instruction.