Texas A&M University-Kingsville: AKM Digital Repository
Not a member yet
1689 research outputs found
Sort by
Estimation of induction motor circuit parameters and efficiency using matlab
No full textPerformance and control strategies of an induction motor depend on proper knowledge of circuit diagram of an induction motor. Induction motor operates on transformer action which is to induce the voltages and currents in the rotor circuit from the stator circuit. By solving the equivalent circuit, one can get the information of efficiency and power factor of the induction motor. To solve this equivalent circuit, it is required to have six different circuit parameters values which are not given on nameplate data of the induction motor. To get this information there are specific experimental tests available. Moreover, it is possible to perform such tests while the motor is working on a specific load and a specific frequency. However, the process becomes impractical and tedious while we need these data for different frequencies and load requirements. Motor nameplate data always consist of efficiencies and power factor of a motor for rated frequency. In this thesis, we have studied an iterative method to get these six circuit parameters using nameplate data. As a result, we have derived mathematical relations between circuit parameters, depended on power factor and efficiencies. Furthermore, using developed Matlab algorithm six parameters can be identified using the proposed least linear square method. Finally, we compute the motor efficiency under different frequencies
Design and simulation of a self-adjustable wave energy converter
No full textOcean wave energy resource potential is vast, and it can significantly contribute to the global energy needs if efficiently explored. However, the commercial harvesting of wave energy is still in its infancy when compared to wind and solar energy. A wave energy converter needs to be able to optimally harvest wave energy and survive the harsh ocean environment at the same time. Of the different types of available wave energy harvesting methods, one promising concept is the heaving point absorber where the heave motion due to the interaction between ocean wave and absorber‘s body generates power. To harvest more energy, the heaving point absorber needs to operate at the resonance region during its interaction with the ocean waves to achieve the optimum oscillation, which is the main challenge with this concept due to the irregular frequencies of the real ocean waves. This research designed a self-adjusted wave energy converter based on heaving point absorber concept that is capable of harvesting wave energy optimally at multiple frequencies and is able to survive the ocean environment during its operating and design life at the same time. Theoretical hydrodynamic and diffraction of floating bodies, computational fluid dynamics, and finite element analysis tools as well as relevant design codes of practice were applied to determine the device power capture rate, stability, static, and its fatigue responses using real ocean wave data from the Gulf of Mexico. Three objectives were set and achieved, including 1) To create a conceptual design of a self-adjusted WEC based on heaving point absorber concept through the optimization of its dimensions, 2) To simulate and estimate the energy capture of the self adjusted WEC through the use of computational fluid dynamics and finite element analysis tools, and 3) To perform a structural reliability analysis of the self-adjusted WEC to ascertain its survivability in the ocean environment. A 10 year wave energy data from a location in the Gulf of Mexico was used to estimate the annual ocean wave energy potential. The data was also used to determine the two most prevalent ocean wave periods which formed the basis of the design and optimization of the dimensions of the wave energy converter. The time resolution of ocean wave data was shown to have considerable effect on the design and power capture of a converter. The results also shown and confirmed that wave energy converters designs are region-specific when we tested the design made for the Gulf of Mexico in another location in Oregon with 40 times wave energy potential but less captured energy. Influence of seasonal changes, diameter etc. on energy capture were also analyzed. The survivability of the ocean wave energy converter for a design life of 30 years which include both static and fatigue analysis was determined
Robustness comparison of asynchronous bounded delay micropipelines utilizing combinational logic versus an inverter chain for delay matching
No full textThis study compares the temperature and supply voltage variation robustness of asynchronous bounded delay Micropipelines, using the critical datapath’s combinational logic for the control path delay matching versus a traditional inverter chain. The experimentation is performed by simulating first, the pipeline with an inverter chain for delay matching; and second, replicating a stage’s critical datapath combinational logic as the control path delay matching element. The ISCAS-85 16×16 multiplier benchmark circuit is used as the test circuit. Simulations show that as supply voltage and temperature varies, a micropipeline with replicated combinational logic for delay insertion is more robust than using a traditional inverter chain, because voltage and temperature variations more similarly affect the control and datapath delays when both are constructed from the same combinational logic versus control path delay matching implemented as an inverter chain, which has substantially different physical characteristics compared to its corresponding worse-case datapath combinational logic.
For this study, the FreePDK45nm technology node by North Carolina State University (NCSU) has been utilized. The standard cells included in the process design kit (PDK) are used to build the micropipeline control and datapath circuits. For schematic and layout of the circuits, Cadence Design Suite is used, along with Calibre for circuit verification and Spectre for netlist simulation
Alternative method for assessing cattle temperament
No full textChronically stressed cattle with excitable temperaments negatively impact the cattle industry. Identifying excitable cattle can improve overall cattle management, but current assessment techniques may not capture a true representation of cattle temperament. Cattle behavior is altered when subjected to restrained versus unrestrained environments. Exit velocity (EV), chute score (CS) and pens score (PS) are methods used to assess cattle temperament; however, EV, CS and PS are conducted in a restrained or confined environments. Thus, a different approach is need to characterize cattle temperament in an unrestrained environment. In this study, two range finders were used to evaluate cattle temperament to measure the distance of flight zones in a pasture setting. Three unrestrained measurements, initial distance (Di), distance moved (Dm) and pasture velocity (PV), were compared to EV, CS, and PS assessments. Results revealed restrained assessments (EV and CS) were correlated to each other and PS (P < 0.05), but not to pasture assessments (Di, Dm, PV) (P < 0.05). Additionally, results indicated pasture assessments were not suitable predictors for restrained assessments, and a combination of CS and Dm (P <0.05) or CS and PV (P < 0.05) could provide producers with sufficient insight on cattle temperament
Designing a robust image steganography algorithm for secure cyberinfrastructure
No full textThere is an enormous need to overcome the increasing challenges of transferring sensitive multimedia data including images over cloud infrastructure platforms in a robust but secure way. Previous solutions to this challenge have been to encrypt sensitive image data before transmission and decrypt upon retrieval of the data. Although encrypted data may not be interpreted by unlawful information hunters, this method has been proved to be unsafe because it is difficult to conceal. In many cases, encryption may not be permitted or appropriate. Furthermore, it is nearly impossible to develop and implement an encryption-decryption scheme for a secure cyberinfrastructure system that will not be compromised over time.
Recently, a newer approach to conceal sensitive data called digital steganography has been developed to augment the failures of encryption schemes. Unlike encryption which does not hide the presence of sensitive data but makes the data inaccessible, steganography is intended to conceal the existence of such data. Hence steganography is very useful in secure cyber-systems.
This thesis aims at developing a new and simple steganography algorithm to embed pictures known as payload images, into image files known as cover images to get stego images. The algorithm used is a novel combination of some of the previous steganography techniques known as the Discrete Cosine Transform (DCT) and the Least Significant Bit (LSB).
The results of the novel method used in this thesis was found to be more effective than some previous methods using the Signal to Noise Ratio (SNR) as the basis of comparison
Ballistic impact on a sandwich-structured composite armor
No full textPeople have been using armor for protection from projectile attacks since the beginning of the civilization. Ballistic impact analyses of sandwich-structured composite armor are necessary to design and develop novel armor for defense sectors. The goal of this study was to design, model, and analyze the dynamic response of the composite armor system under ballistic impact in terms of residual velocity and energy absorption capacity. These key factors of the analysis were investigated for various carbon fiber reinforced polymers as top and bottom skins, with an Aluminum Alloy 7039 corrugated core structure and an assembly of square prismoid-shaped ceramic (SiC) core centerpieces at different velocities (50m/s, 300m/s, 400m/s). After the numeric analysis, Tenax HTS40 12 K 300/Cycom 977-2 skinned sandwich structure was found to be the best combination for the sandwich composite armor. In addition, T300 6k/Epon 862 as skin was simulated with and without carbon nanotube reinforcement. The one with 4% carbon nanotube reinforcement produced 10.38% better ballistic performance than the without one
A remote sensing approach to detecting Old World Bluestems in South Texas
No full textHistorical overgrazing of South Texas rangelands transformed the savanna and prairie to a landscape dominated by woody plants and shrubs interspersed with low seral grass species and bare ground. During the first half of the twentieth century, exotic grass species, coupled with the application of industrial agricultural practices, appeared to be the future of forage production in South Texas and elsewhere. Several of these exotic species, namely the Old World bluestems [(Bothriochloa ischaemum), Kleberg bluestem (Dichanthium annulatum), and Angelton bluestem (Dichanthium aristatum)], buffelgrass (Pennisetum ciliare), guineagrass (Megathyrsus maximus), Lehmann lovegrass (Eragrostis lehmanniana), and bermudagrass (Cynodon dactylon) have escaped pasture cultivation. Additionally, the native grass tanglehead (Heteropogon contortus) has begun displaying invasive behaviors. These species form thick monocultures that simplify vegetation structure, reduce biodiversity, and decrease habitats for many species of wildlife. I determined the feasibility of using remotely sensed data to determine large scale Old World bluestem distribution on study sites in Kingsville and Premont, Texas. I assessed the performance of pixel-based classifications of cover types for National Agriculture Imagery Program (NAIP; 1-m resolution) and Sentinel-2 (10-m) imagery and evaluated the effect of classification resolution with landscape metrics. The NAIP imagery more accurately classified the true distribution of Old World bluestem cover. The lower resolution Sentinel-2 classifications failed to classify small patches and instead aggregated patches
Comparative study of graph clustering algorithms
No full textBasic idea of graph clustering is finding sets of “related” vertices in graphs. Graph clustering has many important applications in computing such as market research, pattern recognition, data analysis, image processing, etc., but due to growing sizes of graphs, even traditionally fast clustering methods can be computationally expensive for real-world graphs. As a first step towards understanding the graph clustering approach, we studied existing algorithms and explored new ideas in the world of graph clustering. We have implemented our algorithm parallelly. We have checked the efficiency and scalability of parallel algorithm on a modern MPI machine to work with large graphs and found that parallel algorithms give more runtime speedup than sequential algorithm
Comparative study of nano-scale standard CMOS versus finfet
No full textPlanar Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) have been leading the semiconductor industry for many decades. To continue Moore’s law, new structures and devices have been developed. One such innovation is Fin Field Effect Transistors (FinFET), which has gained significant interest in the silicon process, which can replace the traditional planar devices. FinFETs, in particular, aim at regaining considerable control of the gate over the channel of the transistor. There are many tradeoffs between these two technologies in terms of power consumption, cost of fabrication, speed, and performance. Complementary Metal-Oxide Semiconductor (CMOS) uses additional and symmetrical pairs of p and n-type MOSFETs for logic functions. Two notable characteristics of CMOS devices are high noise immunity and low static power consumption. After the introduction of a 3-dimensional transistor, most of the errors which were holding back the CMOS technology have been the answer while scaling the sizes from micro to nano. The nanoscale transistor uses a vertical gate that looks like a fin and thus named as FINFET. To change the parameters of parasitic elements, an additional layer was incorporated between 1st metal and the structure of the transistor. FinFET devices have been proposed as promising alternatives to conventional bulk CMOS devices at the nanoscale because of their unique properties, such as improved channel controllability, a high ON, and OFF current proportion decreased short-channel impacts, and relative resistance to gate line-edge unpleasantness.
In this thesis, the comparative study of CMOS and FinFET is investigated considering ring oscillator as a benchmark, which is implemented using both FinFET and CMOS technologies while comparing average power consumption and propagation delay of the models. Here, the ring oscillator is implemented in spice using the simulator as HSPICE. The corresponding is done between the ring oscillator designed in a 16nm process of CMOS and FinFET. The results are compared based on the average power, fall time, rise time, and the frequency of the oscillator, which illustrates the superiority of FinFETs over planar MOS devices. Many researchers have been investigating to develop novel structures to reduce the sizes into the sub-nanometer regime further while overcoming the drawbacks of conventional devices, and one such promising alternatives are Gate-All-Around (GAA) FET, which is still under developmental stages
A study of educational efficiency of the schools of Cameron County, Texas, of districts of less than 500 scholastics
No full textCameron County is situated in the most southern portion of Texas, being bounded on the north by Willacy County, on the west by Hidalgo County, on the south by the Rio Grande river and on the east by the Gulf of Mexico. It contains an area of 840 square miles with a population of 77,560 or an average of 92.3 persons per square mile.
It is a flat farming and citrus region, cut only by an occasional winding resaca and by the Arroyo Colorado. The coastal section is extremely low, being dotted with numerous sand hills and lagoons. A ship channel from the Brazos de Santiago Pass to Port Isabel and to Brownsville, the county seat, opens to the Valley the facilities of water transportation. These resacas, lagoons, channels and arroyos form the only geographical barriers that might have any influence on the location of school district boundary lines or determine the extent of attendance areas.
The land slopes from the Rio Grande in a northeasterly direction, making possible gravity irrigation throughout practically all of the County. With the exception of a small area along the northern edge, irrigation districts have been formed and considerable investments made for the provision of water