Magnetic Shape Memory Alloys (MSMAs) combine shape-change/deformationrecovery abilities of heat driven conventional shape memory alloys (SMA) and magnetic field driven magnetostrictives through martensitic transformation. They are promising for actuator applications, and can be employed as sensors/power-harvesters due to their capability to convert mechanical stimuli into magnetic response or vice versa. The purpose of the present work was to investigate magneto-thermo-mechanical (MTM) response of various MSMAs, under simultaneously applied magnetic field, heat and stress. To accomplish this, two novel testing systems which allowed absolute control on magnetic field and stress/strain in a wide and stable range of temperature were designed and manufactured. MTM characterization of MSMAs enabled us to determine the effects of main parameters on reversible magnetic field-induced phase transformation (FIPT), such as magnetocrystalline anisotropy energy, Zeeman energy, stress hysteresis, thermal hysteresis, critical stress to start stress induced phase transformation and crystal orientation. Conventional SMA characteristics of single crystalline Ni2MnGa and NiMnCoIn and polycrystalline NiMnCoAl and NiMnCoSn MSMAs were investigated using the macroscopic MTM testing system to reveal how these conventional properties were linked to magnetic-field-induced actuation. An actuation stress of 5 MPa and a work output of 157 kJm?3 were obtained by the field-induced martensite variant reorientation (VR) in NiMnGa alloys. FIPT was investigated both in Ni2MnGa MSMA and in NiMnCoIn metamagnetic SMA. It proved as an alternative governing mechanism of field-induced shape change to VR in Ni2MnGa single crystals: one-way and reversible (0.5% cyclic magnetic field induced strain (MFIS) under 22 MPa) stress-assisted FIPTs were realized under low field magnitudes (< 0.7 Tesla) resulting in at least an order of magnitude higher actuation stress levels than those in shape memory alloys literature. The possibility of harvesting waste mechanical work as electrical power by means of VR in NiMnGa MSMAs was explored: without enhanced pickup coil parameters or optimized power conditioning circuitry, 280 mV was harvested at 10 Hz frequency within a strain range of 4.9%. For the first time in magnetic shape memory alloys literature, a fully recoverable MFIS of 3% under 125 MPa was attained on single crystalline metamagnetic SMA NiMnCoIn by means of our microscopic MTM testing system to understand the evolution of FIPT under simultaneously applied magnetic field and stress. Conventional SMA characteristics of polycrystalline bulk NiMnCoAl and sintered compacted-powder NiMnCoSn metamagnetic SMAs were also investigated, with and without applied field.

Three-dimensional (3D) object perception is critical for comprehending and interacting with the world. It develops during infancy and continues through adulthood. One powerful cue used for object perception is uniform coherent motion. The present paper first briefly reviews the current literature concerning object perception using random-dot stimuli and structure-from-motion (SFM) displays. To extend our knowledge in this area, two new studies were conducted to further our understanding of how infants process 3D shape in SFM stimuli. Study 1 examined infants of two age groups (3-5 month-olds and 8-9 month-olds) in a familiarization phase and a test phase. In the familiarization phase, infants were exposed to one of two SFM shapes (cube or cylinder) and in the test phase infants viewed both SFM shapes side-by-side. Extraction of shape was measured through novelty preferences. Results of Study 1 suggest that both age groups successfully extracted 3D shape. Study 2 served as a replication and extension, with the added control for the variable rotational axis. When this variable was controlled for, 3-5 month-olds failed to show a novelty preference during the test phase. These results suggest not only that infants were attending to both the global shape presented in the SFM stimuli as well as the detailed component of the rotational axis of the stimuli, but also that adding the extra change in the component of rotational axis to SFM stimuli makes the task of extracting shape more difficult for infants. These findings contribute to the infant literature by furthering the understanding of infant shape perception.

The topic of stereo video is getting more attention among these days due to its high quality of visual effect. However, the large volume of data is the problem of its application. There is much similarity between the parallax videos. This similarity is obtained by a shape compensation technique. The topic of this thesis is to investigate a compression technique by on the shape compensation stereo video data. The shape transformation in this paper is coded by the kinds of morphological operations to be applied. This processing is a type of operation by which the spatial form or structure of objects within an image are modified. Morphological operation is usually applied to the binary images. There are two problems for the selection of the optimal morphological filter: the collection of the candidate filters and the sources of the voters. For the gray level images the mask operation is changed to be the more complex window weighting operation. By a strategy of slicing the image umbrella, our masked gray morphological operation is also more computation-efficient than the regular gray morphological operation. Experimental results in this thesis have demonstrated that shape compensation is more efficient than motion compensation for the secondary (right) video sequence.

MPEG is a primary standards for dynamic image compression. The error can be introduced in the quantization process of the block DCT transformation . In this sense, the shape compensation by Boolean filter is proposed by us to adjust the intensity distribution of the motion compensated image. That is, our dynamic images are coded by the kinds of Boolean filter in addition to motion vectors after DCT coding. Boolean operation is usually applied to the binary images. The minterms of Boolean operations can be reprensented by masks. For the gray level images the mask operation is changed to be the more complex window operations. More clearly, there are two masks for a miniterm. One is a complement mask. The other is a maximum or minium window. For coding efficiency, in this paper a common complemented mask is used for two miniterms. In this sense, our Boolean filters are limited in a category of two miniterms with a same complemented structure. Experiment results have demonstrated that images going through the extra Boolean filtering have better visual quality than images processed by motion compensation only. The price is paid by the coding complexity and a relatively simple decoding structure. However, it is the decoding process which is more crucial in real time play. Therefore, we successfully integrated the Boolean filtering into MPEG-1 system in software implementation.

In this paper, new intra and inter shape coding algorithms are proposed. The new algorithms are based on chain code. Chain code of an object's contour can be divided into several segments by the smooth contour characteristic. By this property, some techniques can be used for the proposed intra and inter shape coding algorithms. In intra mode, each segment is encoded by specific codes, and the decoding result is lossless. Compared with MPEG-4, M4R, DCC and chain code, the compression ratio is improved. Besides, a new coding scheme is proposed for the inter shape coding. It includes finding break points in a series of chain code, correlation between break points and fine scaling with a tolerant threshold between two similar chain code segments. By detecting the segments, break points can be found. The correlation is performed by computing the curvature difference between break points and contour points. The scaling is a technique for extending or shrinking a segment of chain code. Experimental results show that in the condition of high quality or low bit rate our proposed inter shape coding algorithm obtains better performance than MPEG-4 in compression.

Shape, texture, and angularity are among the properties of aggregates that have a significant effect on the performance of hot-mix asphalt, hydraulic cement concrete, and unbound base and subbase layers. Consequently, there is a need to develop methods that can quantify aggregate shape properties rapidly and accurately. In this study, an improved version of the Aggregate Imaging System (AIMS) was developed to measure the shape characteristics of both fine and coarse aggregates. Improvements were made in the design of the hardware and software components of AIMS to enhance its operational characteristics, reduce human errors, and enhance the automation of test procedure. AIMS was compared against other test methods that have been used for measuring aggregate shape characteristics. The comparison was conducted based on statistical analysis of the accuracy, repeatability, reproducibility, cost, and operational characteristics (e.g. ease of use and interpretation of the results) of these tests. Aggregates that represent a wide range of geographic locations, rock type, and shape characteristics were used in this evaluation. The comparative analysis among the different test methods was conducted using the Analytical Hierarchy Process (AHP). AHP is a process of developing a numerical score to rank test methods based on how each method meets certain criteria of desirable characteristics. The outcomes of the AHP analysis clearly demonstrated the advantages of AIMS over other test methods as a unified system for measuring the shape characteristics of both fine and coarse aggregates. A new aggregate classification methodology based on the distribution of their shape characteristics was developed in this study. This methodology offers several advantages over current methods used in practice. It is based on the distribution of shape characteristics rather than average indices of these characteristics. The coarse aggregate form is determined based on three-dimensional analysis of particles. The fundamental gradient and wavelet methods are used to quantify angularity and surface texture, respectively. The classification methodology can be used for the development of aggregate shape specifications.

This thesis presents procedures to properly simulate naturally fractured reservoirs using dual-porosity models. The main objectives of this work are to: (1) determine if the spontaneous imbibition can be simulated using a two phase CMG simulator and validate it with laboratory experiments in the literature; (2) study the effect of countercurrent imbibition in field scale applications; and (3) develop procedures for using the dual-porosity to simulate fluid displacement in a naturally fractured reservoir. Reservoir simulation techniques, analytical solutions and numerical simulation for a two phase single and dual-porosity are used to achieve our objectives. Analysis of a single matrix block with an injector and a producer well connected by a single fracture is analyzed and compared with both two phase single and dual-porosity models. Procedures for obtaining reliable results when modeling a naturally fractured reservoir with a two phase dual-porosity model are presented and analyzed.

Shape Memory Alloys (SMAs) are metal alloys which are capable of changing their crystallographic structure as a result of externally applied mechanical or thermal loading. This work is a systematic effort to develop a robust, thermodynamics based, 3-D constitutive model for SMAs with special features, dictated by new experimental observations. The new rate independent model accounts in a unified manner for the stress/thermally induced austenite to oriented martensite phase transformation, the thermally induced austenite to self-accommodated martensite phase transformation as well as the reorientation of self-accommodated martensite under applied stress. The model is implemented numerically in 3-D with the help of return-mapping algorithms. Numerical examples, demonstrating the capabilities of the model are also presented. Further, the stationary Fluid-Structure Interaction (FSI) problem is formulated in terms of incompressible Newtonian fluid and a deformable solid. A numerical method is presented for its solution and a numerical implementation is developed. It is used to verify an existing asymptotic solution to the FSI problem in a simple channel geometry. The SMA model is also used in conjunction with the fluid-structure solver to simulate the behavior of SMA based filtering and flow regulating devices. The work also includes a numerical study of wave propagation in SMA rods. An SMA body subjected to external dynamic loading will experience large inelastic deformations that will propagate through the body as phase transformation and/or detwinning shock waves. The wave propagation problem in a cylindrical SMA is studied numerically by an adaptive Finite Element Method. The energy dissipation capabilities of SMA rods are estimated based on the numerical simulations. Comparisons with experimental data are also performed.

The development of a leading edge propeller blade reconfiguration system using Shape Memory Allow (SMA) muscles is presented. This work describes the design and testing of a leading edge flap, which is used to alter the local camber of a propeller blade. The leading edge flap is deflected by SMA wires housed in the blade and maintained in a fixed position with a shaft locking and releasing mechanism. A locking and releasing mechanism is utilized so that constant actuation of the SMAs is not required to maintain leading edge deflection. The profile at 70% span of the propeller blade was used to create a two-dimensional blade for leading edge flap design implementation and load testing. Deflection of up to five degrees was obtained with the final design of the leading edge flap and locking and releasing mechanism. The SMA muscles used to deflect the leading edge were actuated electronically through resistive heating and were controlled by a proportional/integral gain control algorithm with closed-loop feedback from a linear displacement sensor within the blade. With the final design of the leading edge flap and locking and releasing mechanism, a preliminary design for a three-dimensional propeller was created.

The aim of this study is to analyze students¡¦ mathematics concepts in solving Pythagorean Theorem problems presented in two different representations (word problems and word problems with diagrams). The investigators employed the mathematics competence indicators in Grade 1-9 Integrated Curriculum in developing such problems. In analyzing data, the investigator used Schoenfeld¡¦s method in depicting their problem-solving processes, with attention to students¡¦ sequence and difference in time consumption. Four eight grade students with good competence in mathematics and expressions from a secondary school were selected as research subjects. Problems related to Pythagorean Theorem were divided into three types: Shape, Area, and Number. Data were collected using thinking aloud method and semi-structured interview, and triangulation was further applied in protocol analysis. The research results revealed 3 findings: (1) For the ¡§Shape¡¨ type problems, students¡¦ problem-solving concepts varied with different problem representation. For the ¡§Area¡¨ and ¡§Number¡¨ types of problems (without diagram), students were required to use their geometric concept when processing word problems. Students¡¨ use of problem-solving concepts would not significantly vary with problem representation types. However, students¡¦ use of problem-solving methods would affect the types and priorities of concepts used. Generally, the types of mathematics concepts could be made up by the frequency of concepts used, and more types of problem-solving concepts would be used for word problems representation than for word problems with diagrams representation. (2) In terms of the time consumed in the first three problem-solving stages of Schoenfeld, the time required to solve word problems was 1.6 times of that required to solve word problems with diagrams. In terms of the total time consumed, the time required to solve word problems was 1.25 times of that required to solve word problems with diagrams. In the problem-solving stages, students needed to explore the problem first when dealing with word problems before they could go on to solve the problem, and such repetition was more frequent when they dealt with word problems. (3) For both type of problem representations, there is a higher number of correctly-answered problems. This finding indicated that a higher frequency of problem-solving concepts and less repetition in the problem-solving stage were required; and vice versa. As to the sequence of Pythagorean Theorem concepts to be taught, the investigator suggest teachers to start with the concept of area filling in the ¡§Shape¡¨ type of problems to derive Pythagorean Theorem, and further apply the formula to - III - solving ¡§Number¡¨ problems. After students have acquired basic competency in ¡§Shape¡¨ and ¡§Number¡¨ Pythagorean Theorem problems, teachers could explain and introduce this theorem from the perspective of ¡§Area¡¨. Finally, in problem posing, teachers were also advised to apply various contexts; covering all kinds of representations of problems that enhance students¡¦ utilization of mathematics concepts; and to cater for various needs of students.