The electrical and thermal performance of an unglazed photovoltaic thermal (PVT) system integrated with a serpentine coil configured sheet and tube thermal absorber setup was evaluated using water and copper oxide-based nanofluid. An uncooled PVT system reached a maximum panel temperature of 68.4 & nbsp;C at noon and obtained an average electrical efficiency of 12.98%. Water and nanofluid cooling of the PVT system reduced the panel temperature by 15 & nbsp;C and 23.7 & nbsp;C at noontime, respectively. Compared to the uncooled PVT system, the average electrical efficiency of water and nanofluid cooled PVT system increased by 12.32% and 35.67% to obtain 14.58% and 17.61%, respectively. The thermal efficiency of the nanofluid cooled PVT system (71.17%) was significantly higher than water cooling (58.77%) due to maximum heat absorption by nanoparticles. It was also observed that the overall efficiency of the nanofluid cooled PVT system was 21% higher than the water-cooled system. Also, obtained the highest primary energy-saving efficiency for the nanofluid cooled PVT system. (C)& nbsp;2022 Elsevier Ltd. All rights reserved.

Due to the directions and environmental legislations from RoHS (Restrictions of Hazardous Substances), WEEE (World Electrical and Electronic Equipment) and from various countries, lead is banned from alloy making. Lead free solder alloys thus become very popular in electronic package industries. The research people around the globe started searching for new lead free solder alloys which can replace the Sn–Pb alloy. Many lead free solder alloys were identified. SAC alloys were very popular among this. The presence of 3 and 4% of Ag content adds the cost as well as threat were detected in the medical devices due to electrochemical migration. Sn–1Cu–1Ni–1Ag is a promising alloy with good mechanical properties. The corrosion behavior of the Sn–1Cu–1Ni– x Ag ( x = 0, 0.5, 1% by wt.) was studied in this paper using 3.5% by wt. NaCl solution. Microstructure analysis, EDAX analysis was also done. The results show that the corrosion rates were decreased with the addition of Ag. The corrosion rates for 7 days and 14 days were almost same. Combining the mechanical properties and corrosion resistance, Sn–1Cu–1Ni–1Ag is a promising lead free solder alloy.

Automotive radiators are compact heat exchangers used to exchange the heat absorbed from the engine to the cooling media. Purpose-designed nanoparticles of CuO, alumina, titanium dioxide, carbon nanotubes, silica, ferro particles etc dispersed into the carrier liquid enhances the heat transfer capabilities. This paper compares the heat transfer rate using aluminium based nano fluid and nano sized ferrofluid with and without magnetization experimentally in a heat exchanger using water as base fluid. An experimental setup was constructed with facility to measure all required temperatures. Using the obtained data, the optimum heat transfer rate and efficiency of heat exchanger is calculated with different combinations. The size of the particle used for the experiment is 35nm and 29.2nm respectively for aluminium based particle and ferro particle. The temperature difference across the heat exchanger was 6°C when water alone was used as the cooling media. Ferro particles from 1% to 5% were added into the base fluid and it was observed that the optimum temperature difference was noted when 4% ferro particles used with base fluid, the temperature difference increased from 6°C to 11°C at this combination. The ferro particles were then magnetized and when 4% ferro particles were magnetized, the temperature difference increased to 15.6°C. Further increase in ferro particles and magnetization shows reduction in temperature difference. The maximum temperature difference obtained by using aluminium based nano fluid is at 5% addition and the temperature difference is 9.3°C. The comparison shows that magnetized ferrofluid is more efficient than aluminium based fluid in heat exchanging. For validation, the software used is FLUENT and for regression analysis & evaluation, software packages such as MINITAB 18 and MATLAB 16a are used.

Lead is banned in alloy making citing toxicity concerns and environmental legislations. Researchers around the world were in search of new lead free solder alloys which could replace the old Sn–Pb alloy. Solder alloys are important electronic material used in electronics package industries. In this study, shear strength and impact toughness tests were conducted on Sn–0.5Cu–3Bi when different amounts of Ag (0.25, 0.5, 0.75, 1 wt%) is added. Shear strength test is done using micro force test system. Impact toughness test is done using Charpy impact test set up by finding the energy difference before and after impact. Ultimate shear stress is found to be increased from 17.3 to 23 MPa. Yield strength is found to be increased from 23.4 to 28 MPa. Impact toughness of the alloys increased from 10.4 to 11.3 J. EDAX analysis and mapping of the Sn–0.5Cu–3Bi–1Ag is also obtained Sn–0.5Cu–3Bi–1Ag is found to be having good improved shear strength and impact toughness than Sn–0.5Cu–3Bi.

The performance of an internal combustion engine can be evaluated in terms of fuel efficiency and cost savings by addition of nano sized ferrofluid into cooling water system at varying percentage and magnetizing it with varying magnetic intensity. The experiment was undertaken in Maruti 800 cc motor car running at a speed of 40 km/h whose cooling water capacity is three liters. The test was undertaken with water alone as cooling media, water with varying percentage of ferro particles and water with varying concentration of ferro particles and magnetic intensity. The optimum distance travelled and fuel efficiency is calculated and compared with all three combinations. The result showed a difference of 1.388 km/l at optimum composition. For validation, statistical tool such as ANOVA and for regression analysis & evaluation, software packages such as MINITAB 18 and MATLAB 16a are used. (C) 2019 Elsevier Ltd. All rights reserved.

Various environment legislations lead to the ban of Pb in solder alloy making. Solder alloy is an integral part of electronic packaging industry. As a result of this researchers were searching for new combinations without lead which can replace Sn–Pb solder alloy. The new lead free solder joint should possess good mechanical properties, good wetting properties and good corrosion resistance properties. Many lead free solder alloys were discovered. Sn–0.5Cu–3Bi is a good candidate for replacing the Sn–Pb alloy with good properties. The addition of Ag into the alloy enhanced the properties, especially 1% by wt. Ag. In this paper, investigations on the corrosion behavior of Sn–0.5Cu–3Bi–xAg (x = 0, 0.5, 1% by wt.) in 3.5% NaCl is carried out using weight loss method. Microstructure and EDAX analysis were also conducted in the analysis. It is found that the corrosion rate is minimum with 1% by wt. addition of Ag. Corrosion rate is less when compared with the SAC (Sn–Ag–Cu). Sn–0.5Cu–3Bi–1Ag can be considered as a potential lead free solder joint with good corrosion resistance.

Electronic packages that are used these days are exposed to different types of vibration loadings in their usage environment. This vibration exposure can be categorized as harmonic and random vibrations. When reliability assessment of modern electronic systems is considered, vibration loading has an important role to play. One of the biggest challenges facing today is the accurate and rapid assessment of fatigue life under the vibration loading. Conventional solder joints were made of lead-tin alloy. According to many environment legislations and rules, lead is prohibited as an ingredient in the solder alloy. The reason for the prohibition of the usage of the lead is that it poisons the environment. In this study, Sn-0.5Cu-3Bi-1Ag is used as the lead-free solder alloy. Fatigue life prediction of electronic package containing SAC405 is conducted with the aid of vibration testing and Finite element analysis under harmonic vibration loading. A specially designed Plastic Ball Grid Array Package (PBGA) component is mounted on Printed Circuit Board (PCB). It is taken as a test vehicle for the vibration test. The test vehicle is excited by a sinusoidal vibration. The frequency of this excitation equals the fundamental frequency of the test vehicle and it is continued till the component fails. Since the solder balls are very small for direct measurement, Finite Element analysis (FEA) is used for noting down the stresses. The stress versus failures cycles (S-N) curve is made by relating both the stresses on the solder balls obtained and the number of failure cycles from vibration analysis. The fatigue life of the component can be estimated from the generated S-N curve. It is analyzed that the methodology is effective in predicting the component’s life. Hence, the reliability of electronic package can be improved.

Heat exchanger is an essential component of an engine cooling system. Radiators are compact heat exchangers used to transfer the heat absorbed from engine to the cooling media. The jacket cooling water gets cooled and re-circulated into system after exchanging the heat with cooling water in a heat exchanger. Conventional fluids like water, oil, ethylene glycol, etc. possess less heat transfer performance; therefore, it is essential to have a compact and effective heat transfer system to obtain the required heat transfer. A reduction in energy consumption is possible by improving the performance of heat exchanging systems and incorporating various heat transfer enhancement techniques. In this paper, the heat transfer rate using nano-sized ferrofluid with and without magnetization is analysed using CFD simulation and compared with the experimental values obtained from a heat exchanger using water as base fluid. The heat transfer rate is measured using different combinations by varying the percentage of nano particles and by introduction of different magnetic intensity (gauss) on to the ferrofluid. The optimum heat transfer rate and efficiency of heat exchanger is calculated with the different combinations and the values are compared with the values of CFD simulation. CFD simulation was undertaken for water alone as cooling media and for water with ferro particle addition from 2% to 5%. The difference in temperature observed to be similar with experimental values. The deviation is within the acceptable limit and therefore the experimental findings are validated. The experiment was conducted on a parallel flow heat exchanger with water alone as cooling media, water with varying percentage of ferro fluid and water with varying magnetic intensity on ferrofluid. Percentage of ferro particles added up to where the optimum temperature difference could be obtained and the magnetic intensity also varied up to the optimum value.

Lead is restricted in solder joints because of environmental legislations. In this study, a new ternary solder alloy Sn-0.5Cu-3.5Bi is proposed. Alloys prepared using induction furnace have been analysed for their material properties. Melting temperature lies in the range of 219.5-220.5 degrees C. Hardness value lies in the range of 20.5-20.8 Hv. Good wetting property have also been obtained. Grain boundaries were attained from the microstructure evaluation. A comparison with SAC305 and SAC405 also shows that the new alloy is having better properties. Sn-0.5Cu-3.5Bi is a new lead free solder alloy for electronic packages subjected to moderately high temperature surroundings. (C) 2019 Elsevier Ltd. All rights reserved.

Inherent toxicity makes lead a banned material in solder alloy making process. Lead-tin alloy was a favorable alloy used for soldering in electronic packaging manufacturers. As a result of the ban on lead, electronics package industries were looking for novel lead free alloys which can substitute the conventional Sn-Pb alloy. Many alloys were discovered by the scientists. None of them were able to substitute the Sn-Pb alloy and become the market leader. In this paper a new composition with Sn, Cu and Ni is made to analyze which can potentially replace the lead containing solder alloy. Using the design of experiments method, the optimized composition of Cu and Ni is predicted. The full factorial design of experiments with two replications is used to find the optimized composition. Melting temperature, contact angle and hardness were taken as the critical output parameters. Results obtained shows that the optimum composition of Cu and Ni are 1 and 1% by wt.

Cryogenic fuels are generally stored in large insulated tanks. These tanks are subjected to external thermal loads which raise the temperature of the stored fluids thereby leading to convection currents of warmer layers of liquid moving from the boundary to the liquid-vapour interface. The continuous heat in-leak into the tank leads to an increase in the mass of the high temperature fluid termed as stratified propellant mass. Stratified propellant mass is considered a penalty for the launch vehicle. Hence, the accurate prediction of formation of stratified mass is crucial and understanding the evolution of stratified mass and methods to nullify it in a cryogenic tank is essential for increasing payload mass. Objective of the paper is to study the effect of ullage gas properties on interface temperature and thereby stratified mass of LN2 in the tank during draining in the presence of multi-species ullage. Results indicate lower temperature for liquid layers when a non-condensable gas is used for pressurization and draining. Some variations in the temperature of top liquid layers with respect to pressurant gases are also observed. This can be inferred probably due to rate of evaporation and condensation at liquid vapour interface with multispecies ullage.

Lead is banned in the solder alloy composition, citing its inherent toxicity. The researchers were working towards the development of new lead free solder alloys which can replace the old Sn–Pb alloy. In the present paper two new solder alloys are introduced, Sn–0.5Cu–3Bi (96.5% Sn, 0.5% Cu, 3% Bi, all are % by wt) i.e. SCB305 and Sn–1Cu–1Ni (98% Sn–1% Cu–1% Ni) i.e. SCN110. The melting temperature of SCB305 and SCN110 are found to be 231.5 and 232.8°C, respectively. Therefore these two alloys can be used as solder material in electronic packages exposed to moderately higher temperature. Hardness of SCB305 and SCN110 are obtained as 19.8 and 16.1 HV. SCB305 and SCN110 have very good wetting characteristics with contact angle of 28.74° and good wetting characteristics with contact angle of 36.75°, respectively. Microstructure of SCB305 and SCN110 shows that Bi and Ni are evenly distributed in the Sn-matrix. The cost analysis revealed that SCB305 and SCN110 have cost of 23.05 and 20.65 $/kg. The properties of the new alloys were compared with that of SAC305 and SAC405. SCB305 and SCN110 are found to be perfect replacement of Sn–Pb alloy.

Electronic apparatuses are wide-open to diverse vibration loadings. Vibration loading has become very substantial in the reliability valuation of contemporary electronic systems. The present challenge is to implement the vibration fatigue life examination quickly and precisely. Adding to that, lead is used as a solder joint in most of the electronics instruments. Lead is not eco-friendly due to its intrinsic nature of venomousness. A lead free solder joint is used in this paper which is 95.5Sn– 4.0Ag–0.5Cu (SAC405).Vibration analysis is conducted on a printed circuit board element (PCB) on which plastic ball grid array package (PBGA) of specific design is mounted which is our test specimen. The package is soldered to the PCB using Lead free solder material. The PCB which is used in the analysis is divided by drawing lines into elements having discrete points and excitation is given at those points while noting down the response. The PCB and the package along with the solder joint are modeled and modal analysis is done to find the natural frequency. Modal analysis experiment has been done and the finite element analysis results were validated. The mode shapes are extracted at the natural frequencies using DIAMOND software. Frequency Response Function (FRF) real and imaginary parts are obtained through LabVIEW software. The FRF data which are gained through the experiment are given as input to the DIAMOND software. Geometry, nodes, tracelines were also given as input. Then the mode shapes were extracted using the software.

Abstract Lead is known to be banned in alloy making, highlighting toxicity concerns and environmental legislations. Researchers and scholars around the globe were in immediate search of new lead free solder alloys which could potentially replace the old Sn-Pb alloy. In this comprehensive study, shear strength and impact toughness tests were conducted on Sn-1Cu-1Ni when different amounts of Ag (0.25, 0.5, 0.75 1 % by wt.) is added. Shear strength test is tested using micro force test system. Impact toughness test is analyzed using Charpy impact test set up by calculating the energy difference before and after impact. The study reveals that, Ultimate shear stress increased from 19 MPa to 21.3 MPa. Yield strength increased from 27.4 MPa to 29.7 Mpa. Impact toughness of the alloys increased from 9.4 J to 10.1 J. Thus, Sn-1Cu-1Ni-1Ag is found to have improved shear strength and impact toughness than Sn-1Cu-1Ni.

As a result of the ban of lead from solder joints, many lead-free solder joints were developed. Most of the electronic equipment is subjected to random vibration. This study develops an analysis methodology based on finite element analysis and vibration tests to predict the failure and fatigue life of the electronic package soldered using Sn-1Cu-1Ni-1Ag under random vibration. A specially designed printed circuit board having ball grid array packages soldered is used in the study. Finite element model is developed in ANSYS and modal analysis was done. The finite element results were validated with experiments (impact test). Random vibration analysis was also done. These results were validated with random vibration experiments. Using the finite element results, it was predicted that the corner solder joints will fail first. It was observed in the random vibration experiment that corner solder joint failed first and the maximum stress generated was 12.8 MPa. Thus, Sn-1Cu-1Ni-1Ag is a promising lead-free solder joint alloy under random vibration combining with its mechanical properties.

Lead cannot be used in solder alloys due to its deep-rooted toxicity. In the view of this fact, much legislation came into existence to prohibit the usage of lead in solder joints. Many lead free solder alloys came to replace the conventional Sn-Pb solder alloy. This study investigates the effect of addition of Ag (0.25, 0.5, 0.75, 1 wt.%) on the melting behavior, wetting characteristics, hardness and microstructure properties of ternary lead free solder alloy - Sn-1Cu-1Ni. Melting temperature is found to be decreased slightly from 232.2 degrees C to 228.7 degrees C. The distance between the adjacent atoms and the root mean vibration amplitude determines the melting temperature property. Ag3Sn formed in the matrix has changed the melting point characteristics which resulted in the slight decrease of the melting temperature. Contact angle get reduced from 36.75 degrees to 22.87 degrees. Hardness value is found to be increased from 16.1 to 19.2. Ag is found to be uniformly distributed in the microstructure analysis. As far as the data available show, the microstructure of this lead free solder alloy consists of coarse beta-Sn grains. Ag3Sn, Cu6Sn5 and tin in the alloys are found in the eutectic region. The refinement of beta-Sn grains is happened in a good manner due to the addition of particle of Ag. The recommended amount of Ag addition in to the Sn-1Cu-1Ni is 1 wt.%. This lead free alloy can be used in electronic packages exposed to relatively high temperatures.

Lead cannot be used in the solder material anymore due to environmental legislations which is related to the inherent toxicity of lead. This paper investigates the effect of silver (Ag) addition on the melting behavior, microstructure, and microhardness of Ternary lead free solder alloy Sn–0.5Cu–3Bi. The contact angle between Sn–0.5Cu–3Bi and Cu-substrate were also analyzed. Samples with different Ag percentages (0, 0.25, 0.5, 0.75 and 1.0 wt%) in Sn–0.5Cu–3Bi were prepared using an induction furnace, annealing furnace with argon gas. Tests were conducted for melting temperature using TG–DTA analysis, chemical composition using ICP–OES, Hardness using Vickers’s hardness tester and the microstructure using Field emission scanning electron microscopy. The obtained results were thoroughly analyzed. The results show that the Ag addition has striking positive effects on enhancing the properties of the base solder alloy. Melting point is found to be decreasing with the increase in Ag content. Hardness and contact angle were improved with the addition of Ag. The microstructure observations revealed that the Ag was uniformly distributed on the surface of the solder matrix. The recommended content of the Ag to be added into the Sn–0.5Cu–3Bi solder alloy is 1.0 wt%. With the observed better properties it can be considered as the potential alternative to lead–tin alloy.

A methodology is developed for the identification of Energy-Intensified Equipment (EIE) for reliability analysis in the chemical processing industry. There are several methods based on classification that can be used for identifying such equipment, such as Always Better Control/ABC, Vital/Essential/Desirable (VED), Scarce/Difficult/Easily available (SDE), High/Medium/Low (HML), and Fast/Slow/Non-moving (FSN), but these selective inventory control methods do not indicate the criticality of an item. The damage grounds from failure and the failure modes to plan an optimum maintenance program. The method is applicable in understanding the equipment in the operational phase where there is only limited data available. When available data is scarce or generic, critical data is retrieved from some related selective inventory data banks. In this method, based on physical factors, the situation under which the equipment is working, such as external/internal load/pressure, is used in modeling the equipment. Pareto's 80/20 principle is employed to identify its criticality and calculate its risk factor. The current methodology applies criticality importance analysis and criticality allocation to optimize the maintainability correlated with Reliability-Centered Maintenance (RCM) models. Evaluating the reliability of life-threatening equipment in reverse engineering of the (competitive) operational phase is one of the applications of this method. As a case study, EIE is used for assessment of the proposed method and the results identify the equipment and sub-systems that are critical elements from a reliability and maintenance perspective. A benchmark of the results indicates the effectiveness and quality of the method in identification of energy-intensified equipment for reliability analysis.