The development of modern technology in microelectronics and power engineering requires the creation of efficient cooling systems. This is made possible by the use of special fin technology inside the cavity or special heat transfer Ethylene glycol-copper nanofluids to intensify the heat removal from the heat-generating elements. A numerical study of the natural convection of stationary laminar heat transfers in a closed rectangular cavity with a local source of internal volumetric heat generation. For different Rayleigh numbers and different volume fractions of nanoparticles. The system of equations governing the problem was solved numerically by the fluent computer code based on the method of finite volumes. Based on the Boussinesq approximation. Interior and exterior surfaces are maintained at a constant temperature. The study is carried out for Rayleigh numbers ranging from 104 to 106. The effects of different Rayleigh numbers and volume fractions of nanoparticles on natural convection have been studied. The results are presented as isotherms, isocurrents, and local and mean Nusselt numbers. The aim of this study is to see the influence of the thermal Rayleigh number and the volume fraction of the nanoparticles on the rate of heat transfer.

In this paper, a framework for conducting data-driven prognostics presence of a domainshift is introduced. Domain shift is brought about by factors such as changing operations which alterthe distribution of data thus degrading the performance of learned prognostic models. The use ofWeibull-based hazard functions of the kurtosis and shape factor time domain features are exploredand affirmed as not only being trendable and monotonic but robust across operating conditions; thus,desirable for prognosis. In the learning stage, the usual procedure is to use the designated training datawhich is full lifetime data. Unfortunately, a key characteristic of test data is that its truncated whichmay offer a serious impediment to the predicting model’s performance due to it being trained with fulllifetime data only. In this research, the learning data is extended by adding its truncated versions thussignificantly improving the model’s prediction accuracy for test data. In this work, it is demonstratedthat the proposed method results in over 95% accuracy of remaining useful life prediction for bearingsoperated in different operating conditions.

Low Cycle Fatigue (LCF) is a prominent failure mechanism in many design components; therefore, an evaluation of cycles to failure in this regime is of high importance. Most international standards recommend a closed loop strain-controlled mode specimen testing in this regime. However, the ꜪN data obtained from this test is not suitable for life evaluation of parts enduring force-controlled history during actual service without correction for control mode. Many existing procedures, which accounts for cyclic strain stabilization during force-controlled loading may significantly complicate the finite elements analysis (FEA) at solving or post processing stages and are often an inherent source of uncertainty. A heuristic, cost effective and sufficiently accurate approach for LCF life estimation is advocated. The method involves only two force loading FEA simulations, one of the actual parts and the other of the test specimen, using initial unstabilized stress strain curve, followed by a limited number of force-controlled specimens testing. Actual part and specimen life correlation performed using first loading unstabilized equivalent plastic strain value Ꜫp1 under locality and similitude assumptions. Unstabilized strain vs. number of cycles to failure curve Ꜫp1N is constructed and discussion regarding specimen geometry considerations for providing sufficient accuracy is included. Method validation and crack propagation study are provided.

This present work is about simulating and analysing a Vertical Cavity Surface Emitting Laser (VCSEL) structure used in optical fibre communication systems. In this paper a VCSEL structure made of seven Quantum Wells of Indium Gallium Arsenide Phosphide (InGaAsP) emitting at 1550 nm is simulated. The device is analysed looking at the following characteristics: Direct current current and voltage (IV) characteristics, light power against electrical bias, optical gain against electrical bias, light distribution over the structure, output power and threshold current. Specification of material characteristics, ordinary physical models settings, initial VCSEL biasing, mesh declarations, declaration of laser physical models, their optical and electrical parameters were defined using Atlas syntax. Mirror ratings and quantum wells are the two main parameters that were studied and analysed to come up with structure trends. By determining important device parameters such as proper selection of the emission wavelength and choice of material; a VCSEL with an output power of 9.5 mW was simulated and compared with other structures.

Car seats represent a constructive - functional system including a variety of elements, assembled on a specific frame, among those the main components are the seat pan, the seat backrest, and the seat headrest. In order to improve the comfort of the driver and passengers, as well vehicle general safety, the car seats are under of intensive research and implementation of advanced developments.Thus, through of variety of sensors integrated into the seat, some important parameters are analysed for keeping the drivers alert and comfortable while driving semi-autonomous or autonomous cars. For adjustment of the seat linear and angular positions, a special system has been implemented, comprising electric, electronic, and pneumatic elements. Also, seat micro-adjustments are possible through the action of specific actuators. The car seat design and manufacture take into consideration a diverse array of data, based on a large range of parameters to face the diversity of drivers requirements. The present paper is advancing a conceptual development of car complex seat, integrating a number of active elements, with multiple possible adjustments. The new seat model is designed to satisfy a larger diversity of people both in terms of comfort and safety.

In daily activities, serial numbers represent one way to range finished products of different types of production fields and also tracking those objects during their lifetime – ever since their exit of the production site until their recycling. In this paper are presented several types of imprinting techniques as well as a case study for restoration of a modified serial number.

The current accelerated developments within the automotive sector have triggered a series of performance, comfort, safety and design-related issues. Hence, oftentimes manufacturers are challenged to combine various elements so as to achieve an attractive design, without diminishing the vehicle’s dynamic performance. In order to determine the vehicle dynamic performances we carried out an analysis by two methods. In the first part of the paper, we have used the analytical method to establish the dynamic performances of a vehicle. The second part of our study addresses another method to determine the star performances of the vehicle by means of computerized simulations. The first test aimed to determine vehicle starting performances for two vehicle models, with similar technical configuration, but with the same initial data. In the second test, we aimed at determining the start performance for the same car model, with the same initial data, but for different adhesion coefficients

In nature, it acts, simultaneously or successively, synergistically or antagonistically, on small or larger spaces, for a long or very short time, numerous natural or artificial processes that pollute, leading to the alteration of the quality of the environment. The basic activity carried out within the oil scaffolding consists in the extraction of crude oil and gases from the deposits in their exploitation, their collection, separation of phases (crude oil, reservoir water, gas), crude oil treatment, storage and sending to users. Contamination of the field related to drilling-extraction wells with crude oil, heavy petroleum products, salt water, various chemicals, etc. has a random character, but with undesirable implications on soil, surface water and / or groundwater, depending on the nature of the pollutant, its quantity and area of spread Pollution sources in the oil industry, both systematic and accidental, have a greater or lesser spread, depending on the size of the field, the type and composition of the extracted fluids, the extraction technology used, the age of oil exploitation in the area, relief and hydrographic network. Having available the data provided by the pollution diagnosis, it is possible to assess the risk that the investigated pollution represents for the people on the site and for the natural environment. If it turns out that the risk is significant, then the decision is made to switch to depollution works. The choice of an appropriate depollution path is made on the basis of relevant technical and economic criteria, which is a feasibility study. The proposed depollution technology must be the most appropriate for the case at hand and, at the same time, be available on the technology market. The most important part of the paper is dedicated to presenting the results of an experimental study on the depollution of soils contaminated with liquid petroleum products by sparging technologies, in order to ensure a sustainable remedy. The results of the soil analysis used in the experimental determination are presented, as well as the physic - chemical characteristics of the main soil pollutants. In the experimental part, laboratory decontamination of systems consisting of polluted soils was performed at the laboratory level, using air as a depollution agent. The processing of the data obtained from the experimental determinations allowed obtaining qualitative and quantitative information related to the decontamination speed depending on the nature of the soil, the nature and concentration of the pollutant and the temperature of the decontamination air. Estimating the cost places this technology at a low level compared to thermal technologies and slightly higher than microbiological technologies.

The 1.4301 stainless steel is part of the category of austenitic stainless steels, steels which do no undergo heat treatments in general, as they are intended for hot plastic deformation in particular. The aim of the research presented in this paper was to obtain significantly improved characteristics of the resistance properties in relation to the values obtained under classical conditions, by applying heat treatments. Samples taken from the delivery state material underwent annealing, quenching and ageing heat treatments. Subsequently, the samples thus treated were subjected to tests enabling the determination of the correlations between the heat treatment parameters, the structure and the properties.

Highly demand of aesthetic needed made dental composites become a major role as dental restorations. Minimal invasive of sound tissue and the ability to mimic the original teeth also have the recommendation to choose dental composites. The developments of dental composites mostly focus on filler systems to improve mainly in the mechanical and optical properties due to the esthetic aspect of dental care recently has become increasing importance. According to the component of dental composites, the fillers had a big role to determine the properties of dental composite. Many kinds of fillers have been utilized to improve the properties. Two kinds of dental composites had been known based on their fabrication procedure; i.e. experimental and commercial. The experimental dental composites had been produced by the researcher on their formula to obtain good properties while commercial dental composites were made by many manufacturers which have each brand that has each product of excellence, especially in mechanical and optical properties. The aim of this review focused on the mechanical and optical properties of experimental dental composites and commercial dental composites including describes many factors that affect those properties.