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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

The effects of reader’s theater on 6th grade students’ fluency, comprehension, and reading attitude

Sailer, Jennifer K. 05 1900 (has links)
Improving students’ reading fluency is a major challenge heard throughout many classrooms, and identified by the National Reading Panel. Several research studies indicate that one way to improve fluency is through reader’s theater. Those studies also point out that the positive impact from reader’s theater goes beyond fluency to also boost readers’ confidence, motivation, and comprehension. This thesis was designed to examine the effects of reader’s theater on sixth grade students’ fluency, comprehension, and reading attitude. It was also designed to measure the interrelatedness of all of those aspects. The findings indicated statistical significant differences between the fluency pre and post test scores. Statistically, significant differences did not emerge from comprehension, self-concept, and value of reading pre and post test scores; however, qualitatively gains were seen in the area of self-concept and value of reading. / by Jennifer K. Sailer. / Thesis (M.Ed.)--Wichita State University, College of Education, Dept. of Curriculum and Instruction / Includes bibliographic references (leaves 27-29).
52

The effects of activating prior knowledge before reading on students with and without learning disabilities

Warsnak, Amber D. 05 1900 (has links)
Students with learning disabilities use prior knowledge differently than students without learning disabilities. This paper examines what happens to reading fluency, words per minute, and reading comprehension when prior knowledge is activated. By using two reading passages at the fourth grade level, students read one passage without prior knowledge activation and another with prior knowledge activation. The students were timed for words per minute. The reading errors were noted for fluency, and questions were asked to measure comprehension. While students’ individual scores both increased and decreased in all areas when prior knowledge was activated, students with learning disabilities did increase their reading comprehension on average. / by Amber D. Warsnak. / Thesis (M.Ed.)--Wichita State University, College of Education, Dept. of Curriculum and Instruction / Includes bibliographic references (leaves 35-39). / "May 2006."
53

Analysis of GFRP composite tubes for vertical pump application

Sonambekar, Abhijit Arvind 05 1900 (has links)
Composite anisotropic materials are rapidly gaining popularity in various applications. A global trend is towards an increases utilization of these advanced materials in a variety of structural applications. The pump and pipeline industry, and aerospace industry are the areas where use of fiber reinforced plastics have potential advantages over conventional materials. This thesis presents the results of an investigation to predict the behavior of filament wound glass fiber reinforced composite pipe subjected to different types of biaxial loading which typically occur in vertical diffuser pumps. In this study the influence of lay-up configuration and stacking sequence on the failure strength of a multi-angle glass fiber reinforced polymer composite tube was investigated by using finite element analysis. Published experimental results are taken as the basis for validation of the finite element analysis results. MSC-PATRAN was used to create a half model of the composite tube, and LS-DYNA software was used to perform the analysis. It was observed from the analysis that, the winding angle and the stacking sequence have a significant effect on the structural failure strength of the tube. Additional testing would be needed to verify these results; however the study demonstrated that finite element simulations could be used to accurately predict the performance of glass fiber composite tube under biaxial loading, and can be effectively used for direct applications in designing tubular structural components in centrifugal pump and other industries. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering. / "May 2006." / Includes bibliographic references (leaves 87-90)
54

Analysis of honeycomb core properties under different parametric conditions for the head injury criteria compliance in aerospace applications -- FULL TEXT IS NOT AVAILABLE

Venkateshappa, Harish 05 1900 (has links)
There has been enormous boom in the air travel in recent times. There is increasing demand for the technological advancement nowadays towards the safety of the onboard passengers. Certification of aircrafts requires engineers to demonstrate that a head contact with any aircraft interior complies with the Head injury criteria (HIC) threshold of 1000 units specified in 14CFR 23.562, 25.562, 27.562. Analyzing injuries to the head of the occupant when it comes to contact with any aircraft cabin interiors is of serious issue. HIC compliance is a major concern for all the segments of the aircraft industry due to high cost involved in the certification. This research is an attempt to find a cost effective and yet valid approach to solve the HIC problem for the front row bulkhead seats in transport aircrafts. Previous experience, Quasi static testing, Finite element modeling and Madymo biodynamic simulations are utilized for the HIC compliant bulkheads. Madymo (Mathematical Dynamical Model) is a software package which can be used to simulate the dynamic behavior of Mechanical systems. It has a unique combination of fully integrated multibody and finite element techniques. Quasi static testing on various cell size honeycomb core configurations was carried out. Finite element modeling of honeycomb core was done using Msc Patran software package. Comprehensive parametric study has been carried out on different boundary conditions in which the bulkhead may be fixed. Variable thicknesses of the bulkhead which can be used has been looked upon in this study. Different restraint systems and varied seat setback distances have been used for the parametric study. Nylon belt and the Polyester belt are the two different types of belts with different elongation characteristics which are used in this study. The validated madymo models are then used to conduct a parametric study on the effect of the stiffness and strength of the bulkhead on HIC attenuation below the injury levels. / Thesis (M.S.)--Wichita State University, Mechanical Engineering. / "May 2006." / Includes bibliographic references (leaves 66-69)
55

Building a testbed for mini quadrotor unmanned aerial vehicle with protective shroud

Patel, Chirag Amrutbhai 05 1900 (has links)
Potential applications of small rotorcraft unmanned aerial vehicles (UAVs) range from military missions to exploration of the planet Mars (Patrick C. O’Brien, 2003). Tasks such as exploration of unknown territories, formation flying, intelligence gathering etc, require UAV to be capable of flying very close to other flying or steady objects. Exposed rotary wings limit rotorcraft vehicle’s capability to fly in proximity of other objects. In some applications, such as rescue operation, urban warfare etc, it is highly desirable to cover exposed blades of rotorcraft UAV. This thesis work proposes a testbed for a mini rotorcraft UAV with protective shroud to demonstrate the capability of a rotorcraft to continue its flight after an impact with other object in environment, e.g. building wall. The quadrotor configuration is considered as a base vehicle for the testbed. A protective shroud for base vehicle is designed and built to protect rotors against the impact with wall. A closed loop attitude stability controller is developed and tested to ensure the stability of vehicle against high frequency vibrations from the rotors and disturbances from the impact. Experiments are carried out to prove the stability of the quadrotor vehicle after an impact with a building wall. / Thesis (M.S.)--Wichita State University, Dept. of Mechanical Engineering. / Includes bibliographic references (leaves 57-59) / "May 2006."
56

Design of bipedal walking robot and reduction of dynamic impact in joints

Malakar, Bijaya 05 1900 (has links)
Bipedal walking robots have distinguished themselves from other robots not only for their better mobility but also for the increased amount of complexity in their architecture. The issue of walking stability has inherently been related with these in various aspects from dynamics to controls. It has been defined in various ways for different aspects and these definitions have served as guidelines for designing a walking robot. This research is based on a design of a walking robot and development of a walking trajectory. Among the various approaches implemented in order to attain control of two-legged walking, this study attempted to linearize the walking trajectory by dividing it into finite discrete sections. Using the method of kinematics inversion to generate the initial open loop path, the study looks into implementation of the results for a successful walking mechanism. Further it dealt with stepping velocity control by using ground contact trigger and aimed at reducing the stress developed in joints due to dynamic forces. / Thesis (M.S.)--Wichita State University, Dept. of Mechanical Engineering. / "May 2006." / Includes bibliographic references (leaves 73-75).
57

Finite element modeling of energy absorption characteristic of hybrid structure - composite wrapped on a square metal tube

Shetty, Sandeep Kumar 05 1900 (has links)
The study of axial crush behavior of metal and composite tube has become a basis for the design of crashworthy structure in automotive and aircraft applications. Unlike metals, polymer composite material displays little or no plastic deformation characteristics. Research has showed that the hybrid tube usually made of inner aluminum tube over-wrapped with Eglass fiber reinforced epoxy have significantly higher energy absorption than either aluminum tube or composite tube. It is therefore important to have a predictive design tool that could simulate the response of the hybrid structure under impact or crush load. This thesis is aimed at the development and validation of finite element simulation methods for hybrid tubes. The axial crushing behavior and the energy absorption capacity of the aluminum-composite hybrid tube under quasi static and impact loading is studied using the LS-Dyna finite element solver. A square aluminum tube externally wrapped with E glass/epoxy composite layer at ±45° to tube axis is used for finite element analysis. A modified Chang-Chang failure model is used for the composite layers, exhibiting reasonable correlation with the experimental results. Simulations are carried out on composite and aluminum tubes separately. The results indicate that the energy absorption and crush behavior of the hybrid tubes are better than either the composite tubes or the aluminum tubes. In addition, analysis are also conducted on finite element tube to determine the effects of adhesion, ply orientation, and trigger geometry on load displacement response of hybrid tube. / Thesis (M.S.)--Wichita State University, Dept. of Mechanical Engineering. / "May 2006." / Includes bibliographic references (leaves 47-51)
58

Finite element simulation of 3D drilling in unidirectional CFRP composite

Palani, Vijayakumar 05 1900 (has links)
Drilling is probably the most important conventional mechanical process and it is the most widely used machining operations. Prediction of cutting forces for any set of cutting parameters is essential in optimal design and manufacturing of products. It has been predicted that most of the problems associated with hole making operation, such as drilling, can be attributed to the force generated during cutting operation. In addition, prediction of force helps in design and evaluation of cutting tools and fixtures. The drilling of unidirectional carbon epoxy composite using conventional simple flute twist drill with/without the effect of chisel edge is analyzed. In this study, a series of drilling experiments are conducted on carbon fiber-reinforced composite laminates to determine quantitatively the effect of the chisel edge on the thrust force. In addition, tests are conducted to determine the effect of pre-drilling the laminate with a pilot hole. The results show a large reduction in the thrust force when a pilot hole is present which, in effect, removes the chisel edge contribution. An explicit finite element technique employing an Arbitrary Eulerian Lagrangian (ALE) is used in developing a finite element simulation of a 3Ddrilling process, one of the most complex material removal processes. In these simulations the work piece material and the air surrounding it are modeled using ALE elements. The generation of forces can be tracked using this tool. This objective of this thesis is finite element modeling of cutting forces and measuring the cutting forces generated during 3D-drilling process and comparing the forces with the experimental results. The results on the forces are found to be comparable between the FEA and experimental values. The work also discusses the challenges and methodology of using the LS-DYNA ALE capability for the drilling simulation. / Thesis (M.S.)--Wichita State University, Dept. of Mechanical Engineering. / "May 2006." / Includes bibliographic references (leaves 85-89)
59

Prediction of crack growth in aircraft engine bleed air ducts using finite element and crack growth analysis

Lakkundi, Avinash Basavraj 05 1900 (has links)
The bleed air system in an aircraft engine is one of the most important systems for flight operation and is the heart of the aircraft engine pneumatic system. It consists of ducts and components that supply high pressure bleed air from the engine compressor to the other systems. The functioning of bleed air system plays a vital role in flight safety, ground operations, and coordination with other existing systems [1] including fuel system, lubrication system, ignition system, and anti-ice system. A prior Wichita State University Research and Creative Award (URCA) research project entitled "Aircraft Pneumatic Leak Detection Methods" was the motivation for this thesis work. In this research, different inspection techniques were studied to detect leaks in bleed air ducts. Existing conditions such as continuous high pressure and temperature loading within a duct can make it prone to leak because of high stress concentration areas, pre-existing flaws, or manufacturing defects. A general-purpose finite element package, ABAQUS was used for stress analysis of cracked structures such as tubular T-joints. The high stress concentration region at the intersection of the duct joints was assumed to have certain initial flaws. This initial crack flaw was analyzed using line-spring elements to compute the stress intensity factor (SIF). The values of SIF obtained from the present analysis were compared with appropriate results in the literature. Stresses from the finite element analysis were used as input in AFGROW, a crack growth software package consisting of extensive material properties and all necessary fracture mechanics parameters required for crack-growth analysis. Damage tolerance was applied to estimate the life of the duct. The leak-before-break concept was used to determine whether crack growth in the duct would lead to any kind of leak or catastrophic failure. Crack and leak detection techniques to evaluate the crack size are discussed. / Thesis (M.S.)--Wichita State University, Dept. of Mechanical Engineering. / "May 2006." / Includes bibliographic references (leaves 71-75)
60

Prediction of variation in dimensional tolerance due to sheet metal hydroforming using finite element analysis

Pandya, Rajen Subhashchandra 05 1900 (has links)
Hydroforming of aluminum sheets is very important in the aircraft industry, due to the advantages of less wrinkling and cost effectiveness. Numerous research has been conducted in this field, which deals with the development of methods and tools to control accuracy of the bend and prediction of the springback after the sheet metal has been formed. Rivets are the most commonly used fasteners to fit together the subassemblies of the aircraft. The holes for riveting are punched after any forming operation due to the tensile and compressive deformations along the thickness of the sheet metal, which can affect the dimension and position accuracy of the hole. This incurs more cost and time due to the development of special dies for accurately punched holes. It is necessary to develop a method for predicting variation in the holes, which will increase the cost effectiveness of the process. In this research, sheet metal with pre-drilled holes was evaluated for a bending operation using a hydroforming technique. Sheet metal with a variety of thicknesses, bending radii, and bending angles was evaluated. Variation in the dimensional tolerance was attained using the minimum radial separation method. A dataset of dimensional variation in the holes was developed and used for development of the artificial neural network, which was able to predict the dimensional variation of the hole if an unknown pattern of inputs was provided. This study presents the prediction of the dimensional variation of holes due to sheet metal bending using the hydroforming technique. / Thesis (M.S.)--Wichita State University, Dept. of Mechanical Engineering. / "May 2006." / Includes bibliographic references (leaves 74-78)

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