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Effects of Thermo-Mechanical Fatigue and Low Cycle Fatigue Interaction on Performance of Solder Joints
No full textThis paper demonstrates the feasibility of low cycle fatigue effects on the thermo-mechanical fatigue evolution in the
solder joints of a power module. To achieve this goal, FEM
simulation and experimental studies have been carried out. One of the prepared samples was exposed to the sole thermal cycling while another one underwent frequent drop impacts, as indicator of low cycle fatigue event, during the thermal cycling. The FEM results indicate that the thermal cycling leads to the accumulated creep strain in the solder joints. The amount of creep strain considerably increases when the drop impacts are coupled to the thermal cycling. This phenomenon is due to the additional peeling stress applied by drop impacts to the solder joints. It is also revealed that with an increase in the number of drop impacts, the rate of strain accumulation declines which may be due to the restriction of changes led by stress triaxiality. The fractography also validates that the sample exposed to both drop and thermal loadings shows an entire brittle fracture mode. Moreover, the EDS map shows that the elemental distribution heterogeneity and intermetallic growth were created under mutual effects of drop impacts and thermal cycle fatigue
Physicochemical and nutritional characterization of jamun (Syzygium cuminii)
Get PDFJamun (Syzygium cuminii) is an important minor fruits in India. Minor fruits are good source of nutrition and pharmaceuticals properties. Among all minor fruits Jamun is highly perishable but nutritious. It is mainly used for diabetes patients and in the pharmaceuticals industries. It is a good source of anthocyanin, effective against the analgesic properties. There is no proper data available for the Indian Jamun. The fruit is having a very good market value, but due to its unavailability and perishability it is still unexploited. Physicochemical, mechanical and sensory properties had been investigated for Jamun fruit as well as seed in this paper for further use and storage. Weight of the whole fruit was 8.99±1.89gm whereas the seed weight was 1.64±0.21gm. In case of mechanical property whole fruit can be penetrated up-to 4.1mm whereas, at the same load for seed it can penetrate up-to 2.53mm. Purple colour for pulp, juice and whole fruit was-9.7,-0.9, and-0.76 respectively. High amount of polyphenol (203.76±9.84, 386.51±10.25) tannin (94.52±9.19, 388.99±7.34) and anthocyanin (195.58±6.15, 18.47±1.99) present in both fruit and seed. In case of minerals, presence of K, Ca and Na are significant. In case of sensory analysis mouthfeel and colour was good compared to market sample. This study is helpful for the postharvest processing, machine designing and for further analysis of Jamun
In Vitro Studies of the Antimicrobial and Free-Radical Scavenging Potentials of Silver Nanoparticles Biosynthesized From the Extract of Desmostachya bipinnata
Get PDFThe aim of this study was to perform green synthesis of silver nanoparticles (AgNPs) from the leaf extract of Desmostachya bipinnata (Dharba), a medicinally important herb which is widely used across India. Synthesized AgNPs were analyzed by UV-Visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDAX). The results have confirmed that green synthesis of AgNPs leads to the fabrication of sphere-shaped particles with a diameter of 53nm. Furthermore, these AgNPs were subjected to antioxidant and antimicrobial studies against gram-negative and grampositive bacteria, where AgNPs at a concentration of 20mg/mL showed highest zone of inhibition. Synthesized AgNPs were evaluated for their antioxidant activity by 1, 1-diphenyl-2-picryl hydrazyl radical (DPPH), H2O2, and superoxide inhibiting assays; increasing concentration has showed increase in scavenging ability. Cell toxicity was assessed on HepG2 cell lines, and synthesized nanoparticles at a concentration of 128μg/mL produced significant reduction in viability of Hep cells (P<.05). The availability of Dharba throughout the year and the eco-friendly approach in the synthesis of AgNPs coupled with bioactivity has demonstrated its potential as a novel biomaterial which can be used for various biomedical application
Fractography Analysis and Modeling Studies on Friction Stir Welded AA6061/SiC Composite,
No full textThe Friction Stir Welding (FSW) process has proven to be an efficient, reliable, eco-friendly and it is also recorded as one of the most significant welding processes. Weldability is highly depends on the uniform dispersion of reinforcement particles in matrix in welded zone. In this study, the influence of FSW parameters such as Rotational Speed (RS), Axial Force (AF) and Traverse Speed (TS) on tensile strength of aluminium (AA6061)/SiC composite made by stir casting process are
analyzed by using Response Surface Method (RSM). The optimum working condition is identified as; RS of 600 rpm followed by AF of 8 KN and TS of 20 mm/min to obtain an ultimate tensile strength (UTS) of 164.1 MPa. The obtained regression equation is found to have 99% correlation
with the experimental observations. Further the influence study on FSW parameters on Al/SiC composite reveals that RS has a significant effect in determining the weldability followed by AF and TS. Microscopy examination performed on the fractured surface shows a uniform dispersion of SiC particles that enhance the superior tensile property of the composit
Development Of Composite Slabs Of Marble Powder Embedded Epoxy Resin
No full textThis paper presents the preparation and testing of Marble powder reinforced epoxy composites. In this work, we have revealed the behavior of a composite structure reinforced with marble powder. Marble powder reinforced epoxy composites are fabricated by hand lay-up method with various wt % ratio of epoxy and marble powder composition. The focus is on the effects produced on the mechanical and physical properties due to different composition of filler (marble powder). Hardness tests have been carried out and the behavior for different compositions is studied. Water absorption properties also have been assessed for the resultant marble slabs. Results showed that the mechanical properties like hardness and impact strength of marble powder reinforced epoxy were enhanced
Hydrodynamic and Heat Transfer Studies in Riser System for Waste Heat Recovery using Chalcopyrite
Get PDFEnergy, a critical input, is to be efficiently managed via waste heat recovery and energy reuse for the economic viability of a process industry. In particular, cement manufacture demands a huge quantum of energy, for the necessary reactions. Huge amounts of hot effluent gases are generated. Energy recovery from these waste gases is an area that is of contemporary research interest. Now, about 75% of total heat recovery takes place in the riser of the suspension pre-heater system. This article deals with the hydrodynamic and heat transfer aspects of riser typically used in the cement industry. An experimental apparatus was designed and fabricated with provision for the measurement of gas pressure and solid temperatures at different heights of the riser. The system studied was air - chalcopyrite taken in different particle sizes. Acceleration length (LA) determined at different parametric levels was fitted to an empirical correlation: LA/dt = 4.91902(dp/dt)0.10058(ws/wg)-0.11691(ugμg/dt²gρg)0.28574(ρp/ρg)0.42484. An empirical model was developed for Nusselt number as a function of Reynolds and Prandtl numbers using regression analysis: Nu = 0.40969 (Rep)0.99953 (Pr) 0.03569. © 2018 Korean Institute of Chemical Engineers. All rights reserved
Clarification of jamun juice by centrifugation and microfiltration: Analysis of quality parameters, operating conditions, and resistance
Get PDFJamun is a subtropical minor fruit having many medicinal values. It has a distinguish flavor and color. The fruit pulp was depectinized with enzyme at low temperature and the obtained juice was used for clarification process. A comparison between physicochemical properties and operating parameters were performed between centrifuged and microfiltered clarified juice. Several operating conditions (speed and time) for centrifugation and pressure and membrane pore size for microfiltration (MF) had been chosen. Juice obtained from MF with a pressure of 137.89 kPa and membrane pore size of 0.45 µm has the best result in terms of clarity, turbidity, color, and protein concentration. Permeate flux declination was observed after a certain time period (130 min) due to macromolecules and fiber particles present in the initial juice. Fouling of the membrane was due to cake layer resistance (65%), which gave the maximum contribution to the total resistance, but a good percentage of restoration of membrane was observed after CIP treatment. The study will be helpful for scaling up the clarification process in industrial level. Syzygium cumini, known as jambul, jambolan, jamblang, or jamun, is a tropical tree in the flowering plant family of Myrtaceae. A fresh food contains all the nutrients needed for good health, but because it may not always be possible to obtain fresh food, preservation becomes necessary. Clarification is necessary for making homogeneous juice. An attempt has been taken to clarify the jamun juice with microfiltration with different membrane as well as pressure. The data have been compared with traditional clarification process, that is, centrifugation. This article describes the optimization parameter for clarification process as well as the membrane resistance. The results will be helpful to clarify the juice in industrial level and for further research to clarify any other pulpy juice
THE DESIGN OF PERSONNEL PROTECTIVE CLOTHING FOR PROTECTION AGAINST CBRN AGENTS: A REVIEW
Get PDFChemical, Biological, Radiological and Nuclear (CBRN) agents are harmful to living organisms and their surroundings. Many incidents involving CBRN agents have been witnessed in the past. Moreover, CBRN agents are nowadays also being used as modern warfare agents. Protection against CBRN agents is essential from both industrial and national security points of view. There is a need to design personnel protective suits with CBRN protection. In this review, recent advances in protection against CBRN agents using textile media are discussed in detail regarding their application in personnel protective suits. Different types of CBRN agents are presented along with recommended protection corresponding to the toxicity and concentration levels of these agents. Furthermore, various materials and methods used for the modification of textiles and barrier technologies to render protection against exposure to different CBRN agents are also discussed
Effect of velocity ratio of impinging turbulent jets on heat transfer characterstics of heat sink, International Journal of Mechanical Engineering and Technology
No full textA Thermal analysis on heat sink with cylindrical pin fins subjected to two turbulent impinging jets has been carried out by varying the fin base to tip diameter ratio (D/d = 1.0, 1.25, 1.66, 2.5 and 5.0) and also two jet velocity ratio (v1 / v2 = 1.0,
1.25, 1.66, 2.5 and 5.0) respectively for both in both inline and staggered arrangements by using Ansys Icepack with a constant heat input of 20W. The RNG k–ε model has been used to simulate the turbulent flow characteristics over the fins of heat
sink made of Aluminium. A comparison has been made in terms of heat transfer characteristics and pressure drop for both in-line and staggered arrangement of fins. It is observed that heat transfer co-efficient and thermal resistance increases with the
increase in velocity ratio and there is decrease in pressure drop through fin
Mechanical Properties of Fly Ash/ Sawdust Reinforced Epoxy Hybrid Composites
No full textThis study investigated the effect of the resin to filler ratio on the physical and mechanical properties of Epoxy resin hybrid
composites reinforced with fly ash and sawdust. The fundamental properties of the resultant hybrid composite of various compositions, including its density and compressive behavior were investigated. The samples of different composition ratio are subjected to tests like compressive loading, Vickers hardness and moisture absorption test. The results showed that increase in filler quantity to the mixture reduced the cost of the composite as well as improved its durability. However, a consequent decrease in its physical and mechanical properties is also observed because of reduced epoxy polymer content. The optimum percentage for maintaining a good balance among physical, mechanical and durability properties and cost was determined suitably for composite brick formation