Applicability of Semi-Tension Fields to the Back Panel of a Pick-Up Truck

The study and design of light-weight automobiles has emerged as an important area of interest in the government, academia, and the manufacturing industry. Significant advances in vehicle weight reduction technologies have taken place in almost all fields of transportation. Weight reduction is identified as a key factor to achieving fuel-economy, energy efficiency and environmental safety. The main objective of this thesis is to investigate cost effective design methodologies that enable fabrication of light weight structures, which subsequently result in a fuel saving. A few important techniques and trends of weight reduction in the automotive industry over the past few years are studied as part of the thesis. A summary from the survey of various approaches to weight reduction is presented in the literature review. This thesis is based on the theory of semi-tension fields, which was originally applied towards the design of structures in the aircraft industry. A semi-tension field is a post buckling phenomenon in which the load is continued to be carried even after the web has buckled. The advantage of semi-tension fields is twoold: first, by using this theory the structural stability of the original structure is retained; and secondly, its application replaces a comparatively heavy-weight shear resistant web with a thin web, potentially resulting in reduced weight. The semi-tension field theory is applied to the redesign of back panel of a prototype Ford F-150 pick up truck, which was modeled and analyzed using IDEAS Master Series 8 FEA software. The literature review also consists of the survey of several advances in the Semi-tension fields theory, and the corresponding trends in weight reduction. Analytical theories related to semi-tension field-based design and the respective mathematical formulations have also been described. Finite element analyses of the design that resulted from the application of the theory were carried out and results were validated using analytical theories. A technical paper demonstrating the redesign of a door beam was also studied and results are presented as an appendix

Computational models of particle size effects on brittle oxide scale erosion

Metals and alloys designed for machines at elevated temperatures have microstructures and chemistries optimized to provide strength and resistance to oxidation. The majority of the commercial high temperatures metal or alloys intended to use at temperatures below 850°C or so rely on the formation of a continuous surface layer of essentially oxide scale for further oxidation resistance. Erosion of these machine parts by the small solid particle entrained in the liquid or gaseous working environment is a serious problem in many industrial applications. Numerous experiments have been conducted to obtain empirical relations for predicting material loss during erosion and to arrive at an appropriate material for a particular working environment. Arrival of many new materials and surface coatings being used for different applications demand analytical models that are more generic in applying and predicting the volume loss due to erosion. The current thesis work is focused on finite element modeling that takes into account various boundary conditions and predicts the loss of material due to erosion.;Two models, aluminum oxide model and iron/iron-oxide model were developed using IDEAS and analyzed using LS-DYNA3D. The aluminum oxide model was used to validate the computational model with the experimental work of Allan Levy. The results indicated the correlation with the experimental observations. The same procedure is extended to estimate the material loss for iron/iron-oxide model. Several parameters such as size of the erodent, temperature, velocity of the erodent, angle of attack were varied and the influence on volume loss of oxide layer was studied. The results were presented in the form of stress contours and the graphs between the volume loss in mm3 and the parameter affecting erosion

When daily planning improves employee performance: the importance of planning type, engagement, and interruptions

Does planning for a particular workday help employees perform better than on other days they fail to plan? We investigate this question by identifying two distinct types of daily work planning to explain why and when planning improves employees’ daily performance. The first type is time management planning (TMP)—creating task lists, prioritizing tasks, and determining how and when to perform them. We propose that TMP enhances employees’ performance by increasing their work engagement, but that these positive effects are weakened when employees face many interruptions in their day. The second type is contingent planning (CP) in which employees anticipate possible interruptions in their work and plan for them. We propose that CP helps employees stay engaged and perform well despite frequent interruptions. We investigate these hypotheses using a two-week experience-sampling study. Our findings indicate that TMP’s positive effects are conditioned upon the amount of interruptions, but CP has positive effects that are not influenced by the level of interruptions. Through this study, we help inform workers of the different planning methods they can use to increase their daily motivation and performance in dynamic work environments

Design, Facile Synthesis and Characterization of Dichloro Substituted Chalcones and Dihydropyrazole Derivatives for Their Antifungal, Antitubercular and Antiproliferative Activities

Infectious diseases caused by fungi and mycobacteria pose an important problem for humankind. Similarly, cancer is one of the leading causes of death globally. Therefore, there is an urgent need for the development of novel agents to combat the deadly problems of cancer, tuberculosis, and also fungal infections. Hence, in the present study, we designed, synthesized, and characterized 30 compounds including 15 chalcones (2–16) and 15 dihydropyrazoles (17–31) containing dichlorophenyl moiety and also screened these compounds for their antifungal, antitubercular, and antiproliferative activities. Among these compounds, the dihydropyrazoles showed excellent antifungal and antitubercular activities whereas the chalcones exhibited promising antiproliferative activity. Among the dihydropyrazoles, compound 31 containing 2-thienyl moiety showed promising antifungal activity (MIC 5.35 µM), whereas compounds 22 and 24 containing 2,4-difluorophenyl and 4-trifluoromethyl scaffolds revealed significant antitubercular activity with the MICs of 3.96 and 3.67 µM, respectively. Compound 16 containing 2-thienyl moiety in the chalcone series showed the highest anti-proliferative activity with an IC₅₀ value of 17 ± 1 µM. The most active compounds identified through this study could be considered as starting points in the development of drugs with potential antifungal, antitubercular, and antiproliferative activities

Sliding Mode Controller For Unstable Systems

The method proposed by Rojas et al.1 for the design of sliding mode controllers (SMC) for un-stable first order plus time delay systems, is extended for delay-time constant ratio () up to 1.8. The SMC settings obtained for various are fitted by simple equations. Up to = 1.2, the method is found to be more robust than that of latest PID Controller proposed by Padmasree et al.2 There is no method available in literature to stabilize unstable systems using PID controller for > 1.2. Simulation results are also given for a nonlinear bioreactor control proble

Physical Analysis of VO2 Films Grown by Atomic Layer Deposition and RF Magnetron Sputtering

Among the many vanadium suboxides and different stoichiometries, VO2 has received considerable attention due to its remarkable metal-insulator transition (MIT) behavior, which causes a significant reversible change in its electrical and optical properties occurring across the phase transition at 67°C. The initially amorphous VO2 thin films were fabricated by the emerging, Atomic Layer Deposition (ALD) technique with (tetrakis[ethylmethylamino]vanadium) {V(NEtMe)4} as precursor and H2O vapor as oxidation agent. For benchmarking we have also used the RF Magnetron Sputtering technique to deposit metallic vanadium thin films, which were later oxidized during furnace annealing. Post annealing of the as-deposited ALD films was performed in order to obtain the technologically important form of crystallized VO2 thin films using furnace annealing. All film depositions were carried out on native oxide covered (100) Si substrates. The conditions for successful furnace annealing are reported in terms of temperature and annealing gas composition and the physical characterization results are presented. (C) The Author(s) 2014. Published by ECS

Physical Analysis of VO2 Films Grown by Atomic Layer Deposition and RF Magnetron Sputtering

Among the many vanadium suboxides and different stoichiometries, VO2 has received considerable attention due to its remarkable metal-insulator transition (MIT) behavior, which causes a significant reversible change in its electrical and optical properties occurring across the phase transition at 67°C. The initially amorphous VO2 thin films were fabricated by the emerging, Atomic Layer Deposition (ALD) technique with (tetrakis[ethylmethylamino]vanadium) {V(NEtMe)4} as precursor and H2O vapor as oxidation agent. For benchmarking we have also used the RF Magnetron Sputtering technique to deposit metallic vanadium thin films, which were later oxidized during furnace annealing. Post annealing of the as-deposited ALD films was performed in order to obtain the technologically important form of crystallized VO2 thin films using furnace annealing. All film depositions were carried out on native oxide covered (100) Si substrates. The conditions for successful furnace annealing are reported in terms of temperature and annealing gas composition and the physical characterization results are presented. (C) The Author(s) 2014. Published by ECS

Isolation of Two Strong Poly (U) Binding Proteins from Moderate Halophile Halomonas eurihalina and Their Identification as Cold Shock Proteins

Cold shock proteins (Csp) are known to be expressed in response to sudden decrease in temperature. They are thought to be involved in a number of cellular processes viz., RNA chaperone activity, translation, transcription, nucleoid condensation. During our studies on ribosomal protein S1 in moderate halophile Halomonas eurihalina, we observed the presence of two strong poly (U) binding proteins in abundance in cell extracts from cells grown under normal growth conditions. The proteins can be isolated in a single step using Poly (U) cellulose chromatography. The proteins were identified as major cold shock proteins belonging to Csp A family by MALDI-TOF and bioinformatic analysis. Csp 12 kDa was found in both exponential and stationary phases whereas Csp 8 kDa is found only in exponential phase