Modeling Residual Stress Development in Hybrid Processing by Additive Manufacturing and Laser Shock Peening

The term “hybrid” has been widely applied to many areas of manufacturing. Naturally, that term has found a home in additive manufacturing as well. Hybrid additive manufacturing or hybrid-AM has been used to describe multi-material printing, combined machines (e.g., deposition printing and milling machine center), and combined processes (e.g., printing and interlayer laser re-melting). The capabilities afforded by hybrid-AM are rewriting the design rules for materials and adding a new dimension in the design for additive manufacturing paradigm. This work focuses on hybrid-AM processes, which are defined as the use of additive manufacturing (AM) with one or more secondary processes or energy sources that are fully coupled and synergistically affect part quality, functionality, and/or process performance. Secondary processes and energy sources include subtractive and transformative manufacturing technologies, such as machining, re-melting, peening, rolling, and friction stir processing. Of particular interest to this research is combining additive manufacturing with laser shock peening (LSP) in a cyclic process chain to print 3D mechanical properties. Additive manufacturing of metals often results in parts with unfavorable mechanical properties. Laser shock peening is a high strain rate mechanical surface treatment that hammers a work piece and induces favorable mechanical properties. Peening strain hardens a surface and imparts compressive residual stresses improving the mechanical properties of the material. The overarching objective of this work is to investigate the role LSP has on layer-by-layer processing of 3D printed metals. As a first study in this field, this thesis primarily focuses on the following: (1) defining hybrid-AM in relation to hybrid manufacturing and classifying hybrid-AM processes and (2) modeling hybrid-AM by LSP to understand the role of hybrid process parameters on temporal and spatial residual stress development. A finite element model was developed to help understand thermal and mechanical cancellation of residual stress when cyclically coupling printing and peening. Results indicate layer peening frequency is a critical process parameter and highly interdependent on the heat generated by the printing laser source. Optimum hybrid process conditions were found to exists that favorably enhance mechanical properties. With this demonstration, hybrid-AM has ushered in the next evolutionary step in additive manufacturing and has the potential to profoundly change the way high value metal goods are manufactured. Advisor: Michael P. Seal

Driving Forces for the Success of Food Ordering and Delivery Apps: A Descriptive Study

Ever changing demographics customers demanded changes in practices of marketers and especially in food ordering and delivery sector. Revolutionary advancement in information technology and communication has amended the way customers interact with sellers and particularly in the field of ready food. Customers can easily order the food and get it delivered at their door steps than earlier with the help of food delivery apps. The industry is growing at a pace than the expected due to many forces like convenience to customers, cost benefit, flexibility, more options to choose, time saving etc. The present study is based on previous researchers conducted on similar subject and it will emphasise on understanding the reasons for success of food ordering and delivery applications

4-Chloro-N-(3-chloro­phen­yl)benzamide

The title compound, C13H9Cl2N, has an intra­molecular C—H⋯O close contact, and presents the NH group syn to the meta-chloro group in the aniline ring and trans to the C=O group. The crystal packing is formed by infinite chains of N—H⋯O hydrogen bonds along the c axis. Cl⋯Cl [3.474 (1) Å] contacts link chains. The crystal used for data collection was a twin, the domains related by the twin law 0.948 (1)/0.052 (1)

Modeling and Thermal Conduction and Static Analysis of an IC Engine Piston using CATIA V5 Tool and ANSYS

In now a days technology, diesel engine plays an important role in the transportation sector, agriculture pumping sets etc, where large amount of diesel consumed. But according to the ministry of petroleum, the petroleum fuels will last in few years. So, one must concentrate much on the diesel engine modifications so that the amount of fuel consumption and the environmental pollutions can be reduced. The temperature distribution in the piston is a crucial parameter which influences the thermal stress and deformations in the piston materials. So in the present work I tried thermal conductivity and static analysis on cast iron, aluminium and brass materials based pistons

A CASE REPORT ON DRUG INDUCED GYNACOMASTIA

Gynacomastia is a rare condition in males with a symptom of enlarged breast tissue size. It is generally caused by altered ratio of estrogens to androgens in the male individuals. A cause includes several diseases and nearly25% is associate with drugs. A mostly used drug that causes gynacomastia includes spironolactone, amlodepine, TCAs, and ketoconazole. It is a rare side effect. But it has a occurrence of 1% in amlodepine and 1.2% in spironolactone. Diagnosis is majorly done by presence of symptoms like increased breast tissue, and it should be differentiate with pseudo disease, and the increasing nature may be of one side or on both side of individuals. Presence of polactin secreting tumor may induce milk ejection from male breasts. Mostly it is resolved with in one to two months of discontinuation of suspected drug. Mastectomy is the only surgical procedure where the increased breast tissue is removed. Drugs like aromatase inhibitors, estrogen receptor modulators can also be used, but has no clinical practice in males

Finite Element Analysis of Wire Drawing Process with different die contours

Finite element method is a numerical analysis tool for analyzing complex problems. It was originally developed as a tool for structural, Thermal; fluent analysis and magnetic, electrical current flow analysis but the theory and formulation has been progressively gives approximate solutions. I have taken the problem of understanding wire drawing process from theory of pure plasticity and Avitzur’s theory of law’s ‘Wire Drawing through Conical Dies of small cone angles and large cone angles’ This theory was used to obtain the drawing load. Wire is drawn through dies with different die contours viz. plain die with die land, Convex die, Concave die. Hence I found  least wire drawing defects and die life increased. Loads were applying to the finite element model treating the problem to be axi symmetric. The problem to be solving by using ANSYS 10 classic  a popular FEA software package

Modeling And Biomechanical Analysis Of Human Knee Joint

The main objective of the present work is to implement the computer aided technology to study the biomechanical behavior of human knee joint which consists of Femur, Tibia, Patella, Menisci, Posterior Cruciate Ligament (PCL), Anterior Cruciate Ligament (ACL), Medial Collateral Ligament (MCL), and Lateral Collateral Ligament (LCL). Three-Dimensional (3D) model of knee joint was created. The Mechanical properties like young’s modules, Poisson’s ratio of the human bones will vary from person to person, in general according to age, weight, gender, and feeding habits. We considered for this work to create a 3D model using cadaver bones of male 30years old, 1.70m tall, and weight was 66kg.which is collected from Anatomy Department of SRM Medical College and Research Institute, Kattankulathur. The individual bones femur, tibia and patella are modeled using Solid Works. The biomechanical behavior of individual bone, assembly model and flexion angles under varying loading conditions are studied

Preparation of Fluconazole β-Cyclodextrin Complex Ocuserts: In Vitro and In Vivo Evaluation

The main purpose of the present study was to develop ocuserts of Fluconazole β-CD (beta-cyclodextrin) complex and to evaluate both in vitro and in vivo. Fluconazole was made complex with β-CD, and the release rate was controlled by HPMC K4M and ethyl cellulose polymers using dibutyl Phthalate as permeability enhancer. Drug-polymer interactions were studied by Fourier transform infrared spectroscopic studies. The formulated ocuserts were tested for physicochemical parameters of in vitro release and in vivo permeation in rabbits. The optimized formulations (F-5 and F-8) were subjected to stability studies. The formulated ocuserts were found to have good physical characters, thickness, diameter, uniformity in weight, folding endurance, less moisture absorption, and controlled release of drug both in vitro and in vivo. The optimized formulations retained their characteristics even after stability studies. The study clearly showed that this technique was an effective way of formulating ocuserts for retaining the drug concentration at the intended site of action for a sufficient period of time and to elicit the desired pharmacological response

Cloning, characterization and expression analysis of porcine microRNAs

Background: MicroRNAs (miRNAs) are small ~22-nt regulatory RNAs that can silence target genes, by blocking their protein production or degrading the mRNAs. Pig is an important animal in the agriculture industry because of its utility in the meat production. Besides, pig has tremendous biomedical importance as a model organism because of its closer proximity to humans than the mouse model. Several hundreds of miRNAs have been identified from mammals, humans, mice and rats, but little is known about the miRNA component in the pig genome. Here, we adopted an experimental approach to identify conserved and unique miRNAs and characterize their expression patterns in diverse tissues of pig.Results: By sequencing a small RNA library generated using pooled RNA from the pig heart, liver and thymus; we identified a total of 120 conserved miRNA homologs in pig. Expression analysis of conserved miRNAs in 14 different tissue types revealed heart-specific expression of miR-499 and miR-208 and liver-specific expression of miR-122. Additionally, miR-1 and miR-133 in the heart, miR-181a and miR-142-3p in the thymus, miR-194 in the liver, and miR-143 in the stomach showed the highest levels of expression. miR-22, miR-26b, miR-29c and miR-30c showed ubiquitous expression in diverse tissues. The expression patterns of pig-specific miRNAs also varied among the tissues examined.Conclusion: Identification of 120 miRNAs and determination of the spatial expression patterns of a sub-set of these in the pig is a valuable resource for molecular biologists, breeders, and biomedical investigators interested in post-transcriptional gene regulation in pig and in related mammals, including humans.Peer reviewedBiochemistry and Molecular BiologyAnimal Scienc