The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In line with the United Nations framework Convention on climate change, developing and using renewable Solar energy Sources have become vital for ensuring energy sustainability in Sub-Sahara Africa. Energy poverty is becoming a serious issue and there is every need to harness all available opportunity in dealing with this menace. This paper, therefore, proposes a solar heating system for residential...
Heat management is one of the major challenges in modern electronic devices. The higher performance results in a production of greater amount of heat which needs to be efficiently dissipated so as to ensure the electronic devices operational during the period of lifetime. This paper discusses the application of micro- and nano-materials in thermal interface materials (TIM) used for heat management...
Contactless dosing of minute amounts of molten metals in the form of micron sized droplets is a promising technology with applications in the area of three dimensional printing (3DP) and electronics manufacturing. However the generation of droplets of higher melting point metals, such as aluminum and its alloys, has proven to be a challenging task. Difficulties arise mainly due to the high temperatures...
Litz wire has been widely utilized for heating coils of high frequency induction cookers. However, these coils often suffer from large winding height due to low space factor of Litz wire. Certainly, rectangular wire may reduce the winding height of the coil owing to its high space factor. However, the rectangular wire tends to suffer from large copper loss caused by the skin effect and the proximity...
A through-hole less microstrip line to waveguide transition is proposed in this paper. Conventional transitions are required through-holes in order to prevent unwanted emission in the substrate. However, the product cost of the transition is increased by making through-holes. In addition, the through-holes will be broken by heat deformation of the dielectric so that the characteristics of the transition...
A 2.5D package with interposer is proposed for wide bandgap (WBG) power modules. Low temperature co-fired ceramic (LTCC) is used for the interposer because its coefficient of thermal expansion (CTE) is closely matched to those of WBG devices as well as its flexibility to have complex structures and through-hole vias built on it. Furthermore, its thermal performance can be enhanced through the addition...
This paper presents the design approach of a power train used in an advanced high-lift system for future aircraft. Aircraft applications require an ultra-light and integrated design leading to an electrical machine with a high power to weight ratio of 2.82 kW/kg. To achieve additional high lift during take-off and landing, air is blown out at the back flaps of the aircraft wings using a turbo compressor...
Phase change materials have been of increasing interest in thermal management of power batteries due to their high latent heat with minimum volume change. In this work, a numerical study of phase change materials is presented for the purpose of thermal control of the cylindrical power battery cells for applications in electric vehicles. Uniform heat density was applied at the battery cell surrounded...
Innovative application of carbon composite layers into multilayer printed circuit boards affords CTE matching to semiconductor materials, PCB warpage control, weight reduction, heat transfer, and reduced component operating temperatures for improved performance and enhanced reliability. Manufacturing processes have been developed and matured for thin sheets of CTE-matched composites, attributes and...
We present a miniaturized lithium niobate (LiNbO3) pyroelectric ionizer with enhanced ionization using copper electrodes attached to the LiNbO3 crystal poled surfaces. The modified device shows a ∼2.4x improvement in ionization count, without any increase in the heating power applied to the crystal. The ionization events had peak and average ionization currents of 44.8 nA and 9.36 pA respectively...
The electrical explosion of fine metal wire has been used as a common way to investigate the behavior of individual wire in the initial stage of wire-array Z-pinch before the global magnetic field dominates. This paper presents the experimental results of the electrical explosion of copper wires using negative polarity current with magnitude of 1∼2kA. The 20μm-diameter copper wires with different...
Recent progress in wafer level packaging technologies has enabled high power flip chip (FC-LEDs) for direct assembly on printed circuit boards (PCB) for general and automotive lighting applications. Based on LEDs with a light emitting area of 0.5mm2 arrays for miniaturized modules are realized. The individual LEDs are single addressable, the pitch is solely 790µm and the gap between the light emitting...
To avoid the use of high-lead-containing solders in electronics, new lead-free materials and bonding processes are desirable in the world and some solutions have explored for high-temperature applications. Recently, focusing on the use of nanoscale materials, the sintering behavior of nanoparticles has attracted interest as a high-temperature bonding processes. In this study, a feasibility study has...
Soldering of packaged electronic components using industry standard Sn-Ag-Cu (SAC) lead-free solders on low-cost foils, which are often the substrate of choice for flexible electronics, is challenging. This is mainly originating from the fact that the reflow temperatures of these solder alloys are normally higher than the maximum processing temperature of the low-cost flex foils. To enable component...
W/Cu composites have received much attention for applications as in electronic packaging and heat sink materials. There exists difficulties in fabricating W/Cu composites due to the mutual insolubility of tungsten and copper. In this article, high density 1 wt. %Ag-W/Cu composites are prepared by sintering the mixed powders of copper-coated tungsten powders and silver-coated copper powders under different...
With the rapid development of three-dimensional (3D) integration technology, the through silicon via (TSV) approach has become the main trend of study. However the protrusion of cooper in TSV (TSV-Cu) due to the thermal mismatch of different materials in TSV structure imposes serious reliability problems. In this paper therefore focuses on the TSV-Cu protrusion effect under different annealing conditions...
A 2.5D package is referred to as the packaging of multiple chips on an interposer made of silicon or glass featured with through-vias filled with copper as electrical interconnects. Thermal management remains a challenge due to the integration of dissimilar chips such as logic and memory chips on a common interposer in molded package format. In this paper, a partially molded 2.5D package (PM package)...
This paper considers the control of the grain growth in a copper thin film using a multi-zone micro heater array. The overall system is a multi-input/multi-output (MIMO) control system: currents of 10 micro heaters as input and local microstructure (mean grain sizes) as output. We develop a biased Monte-Carlo (MC) model to simulate complete microstructure evolution in response to the temperature field...
From the point of view of energy consumption, LED technology is the most efficient lighting method at present. Thermal and electrical aspects as well as mechanical issues should be considered when designing a LED lighting system. Thermal requirements are usually linked with the mechanical design, meaning that the lighting unit heat sink represents the enclosure assembly. In an attempt to obtain the...
It is important to prevent re-ignition after the arc interruption in the circuit breaker. A number of cathode spots generates, when the vacuum circuit breaker is extinguishing the arc in a vacuum. The cathode spot melt the cathode and the cathode is evaporated, because it has a high energy density. A metal vapor generated from the cathode spot becomes a factor of re-ignition when the transient recovery...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.