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This paper introduces a thermal design method for 3D integration, using stacked thermal chips consisting of 100 polysilicon heaters in a 30 mm by 30 mm area on each chip to verify thermal models. For each heater, two levels of thermal load can be selected. Thermal effects from hot-spots in stacked chips were measured and verified in simulation results. Through this investigation, thermal models with...
Miniaturized electrochemical sensors often face the problem of short life spans due to drift, blockage or biofilm formation. We propose a miniaturized normally closed valve with a hydrogel actuator to regulate sensor exposure and to facilitate rinsing and recalibration steps within a measurement regime. The used Low Temperature Co-fired Ceramics technology (LTCC) allows the implementation of valve,...
Permanent magnet synchronous machines (PMSMs) operation above based speed is typically achieved by injecting negative d-axis current to produce flux weakening. However, this increases permanent magnet (PM) losses, reducing therefore the machine efficiency. Previous studies have reported that PM loss increase in flux weakening operation is due to the increase of the airgap flux harmonic content. These...
Torque production capability of permanent magnet synchronous machines (PMSMs) depends on the permanent magnets (PM) magnetization state (MS). MS is a function of PM initial magnetization level, decreasing as temperature increases. Furthermore, excessive PM temperature can produce irreversible PM demagnetization. PM MS and temperature measurement/estimation is therefore important both for torque control...
In the recent years more and more attention has been directed to the study of potential application of ferrite nanoparticles as the humidity sensing materials. In this paper, we reports the humidity sensing characteristics of yttrium orthoferrite (YFeO3) nanoparticles synthesized by a mechanochemical route from mixture of Y2O3 and α-Fe2O3 powders in a planetary ball mill. Structural analysis of ultrafine...
We present WinATE, a new computer program to measure the electronic transport properties of materials with energy applications. The C++ program we describe here is designed with a user-friendly graphical interface to automate measurement. WinATE controls laboratory test and measurement equipment through a RS-232 serial interface. It was designed to measure electronic properties of synthesized materials...
This Polyimide film has excellent electrical properties and it serves as an important insulating material which is widely used in the variable-frequency motor and wind generator. Since high temperature is a significant reason for degradation in insulation, the space charge distributions of polyimide (PI) films in high temperature condition is worth investigating. Under different temperature, the conductivity...
The river pollution has become a prominently environmental problem to human survival. Thus it is in urgent demand for real-time monitoring of river water. However, traditional methods have some disadvantages such as complicated instrument, high cost and cumbersome operation. Herein, we developed wireless conductivity sensor, which forms a monitoring network system based on ZigBee. The node of the...
The study is devoted to the problem of establishing the correlation between the chemical and phase composition of Ni(1-x)Wx alloys in a wide range of temperatures and the behavior of their lattice and electronic properties. Lattice parameters, macroscopic density and electrical resistivity of Ni — W alloys with different tungsten content were measured. It is shown that the concentration dependences...
Vacuum interrupter(VI) with axial magnetic electrode has superior arcing performance and well-distributed of contact erosion. Two kinds of axial magnetic electrode were assigned in this paper, which included cup shaped and horseshoe axial magnetic electrode. The objective of this paper is to research the current breaking and carrying performance of VI with cup shaped and horseshoe axial magnetic electrode,...
The management of irrigation based on the monitoring of soil electrical parameters allows to rationalize the amount of resources used with the objective of developing a sustainable agriculture. In this sense, the present work presents a sensor of dielectric constant and conductivity of soil based on auto-balancing bridge circuit. The advances presented in this paper are related to the evaluation of...
Scanning Thermal Microscopy (SThM) is a key technique for thermophysical property measurements with a submicrometric spatial resolution. The European project QUANTIHEAT “Quantitative scanning probe microscopy techniques for heat transfer management in nanomaterials and nanodevices” is centred around this technique. Project aims at solving the problems of thermal metrology at the nanoscale by delivering...
Increasing energy demand and depleting fossil fuels make it imperative to shift to more efficient energy sources. Thermoelectric materials can convert waste heat into electrical energy by means of the Thermopower or Seebeck effect. Nanowires are promising candidates to increase the efficiency of thermo-electric conversion because their low dimensionality is predicted to increase the Seebeck effect...
Temperature dependent substrate ramp measurements on AlGaN/GaN power high-electron-mobility transistors (HEMTs) are used to extract information on charge redistribution in the buffer structure as a function of substrate bias. The measurements are compared to a theoretical model, representing the ideal capacitive buffer stack. It is found that at room temperature some negative charge is stored in the...
The mathematical model for temperature field analysis of the new hybrid magnetic bearing has been presented in the paper. The distributions of temperature which have been obtained from 2D and 3D simulations were compared with the results from the physical model testing of the hybrid bearing.
Nanocomposite material for power cable insulation has been under extensive research for quite a long time. Advanced organic and inorganic nano filler of metals and non metals with conductive, semi-conductive and insulating inheritance were wide options. The authors prepared and investigated nanocomposite samples made with low density polyethylene as base resin with several nanofillers including nanofiller...
The paper presents analysis of thermal properties of natural ester modified by nanoparticles C60 and TiO2, used in power transformers. The measurements of thermal properties, such as thermal conductivity, kinematic viscosity, specific heat, density, and thermal expansion were carried out. Measurements were carried out at a temperature of 25 °C, 40 °C, 60 °C and 80 °C. On the basis of measurement results,...
Increasing availability of thermal imaging technology made it possible to carry out thermal quality control of vegetables and fruits in the process of sorting them. For the effective management of thermal control, it is necessary to ensure its optimal regimes, which are largely determined by the power and time of the thermal impact. In order to choose these parameters it is necessary to know the thermophysical...
Composites of Low-density polyethylene (LDPE) containing 1–5 wt% of Si/SiO2 core/shell nanoparticles were fabricated by ball milling method. The neat LDPE and its composites were characterized by several experimental techniques such as DSC, SEM, BDS, AC breakdown, and erosion test to better understand the effects of Si/SiO2 nanoparticle on thermal and dielectric properties of the composites. The results...
The development of advanced dielectric materials with high thermal conductivity is of crucial importance in modern electronic and power equipment systems. Herein, multilayer graphene nanosheets/epoxy nanocomposites with enhanced thermal conductivity were fabricated by solution blended processes. It was found that the incorporation of graphene nanosheets had little impact on thermogravimetric properties...
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