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An investigation of a solid-state lighting (SSL) luminaire with the focus on the electronic driver which has been exposed to a standard wet hot temperature operating life (WHTOL) of 85% RH and 85°C in order to assess reliability of prolonged exposer to a harsh environment has been conducted. SSL luminaires are beginning introduced as headlamps in some of today's luxury automobiles and may also be...
In this work, a new wedge delamination technique for measurement of interfacial fracture strength is presented. This method can be implemented to assess the interfacial fracture behavior of underfill and silicon in flip-chip packages. Our method offers substantial advantages over traditional interfacial test methods which can be difficult to implement on brittle materials like silicon die. The efficacy...
A reduced order model based on proper orthogonal decomposition (POD) has been applied to a multi-fin SOI field effective transistor (FinFET) to develop a compact thermal model. The approach projects the simulation domain onto a function space in order to reduce the numerical degrees of freedom (DOF). The approach does not require any assumption about the physical geometry, dimensions, or heat flow...
This paper presents numerical simulations based on the concept of local and global dimensional analysis to reproduce the thermodynamics and aerodynamics of server-fins, i.e., detachable flat/curved fins on the inlet/outlet of a server, for enhancing energy efficiency in data centers. Server-fin designs, combinations of shapes and opening angles, are evaluated by transient analysis, vorticity analysis,...
In this effort, theoretical modeling was employed to understand the impact of bypass on the flow performance of air cooled heat sinks. Fundamental mass and flow energy conservation equations across a longitudinal fin heat sink and the bypass regions were applied and a generic parameter, referred as the Flow Bypass Factor, was identified from the theoretical solution that mathematically captures the...
Solid-liquid phase change materials (PCMs) can be used as a transient thermal management technique due to their ability to store significant amounts of heat through the solid liquid phase change. It is common to improve the low thermal conductivity of PCMs by adding nanoparticles, however, this addition changes some of the physical properties of the material, including viscosity, possibly hindering...
In recent years, there is increasing interest in copper wirebond technology as an alternative to gold wirebond in microelectronic devices due to its superior electrical performance and low cost. At present, validated constitutive models for the strain rate and temperature dependent behavior of Cu free air ball (FAB) appear to be largely missing in the literature. The lack of reliable constitutive...
Energy has been identified as one of the most important problems during the last few years. While energy generation and new energy resources are critical, energy efficiency in production, transportation and utilization are as important as well. One of those energy efficient technologies may reduce consumed energy in buildings from 20 percent to less than 5 percent. A novel lighting technology has...
Generally, a porous jump model is used for rapid air flow simulations (without resolving the tile pore structure) through perforated tiles in data centers. The porous jump model only specifies a step pressure loss at the tile surface, without any influence on the flow field. However, in reality, the downstream flowfield is affected because of the momentum rise of air due to acceleration of air through...
Industry migration to leadfree solders has resulted in a proliferation of a wide variety of solder alloy compositions. The most popular amongst these are the Sn-Ag-Cu family of alloys like SAC105 and SAC305. Electronics subjected to shock and vibration may experience strain rates of 1–100 per sec. Electronic product may often be exposed to high temperature during storage, operation and handling in...
This is an effort to use natural convection inside a room to enhance the heat flow from a ceiling-mounted recessed LED fixture. Thermal performance of recessed fixtures is evaluated experimentally in a wooden box specified by Underwriters Laboratories, called a UL box. The UL box is approximately 0.67 × 0.62 × 0.46 m and is used to emulate an insulated ceiling for testing purposes. The UL box is suspended...
Penetration of a wetting liquid into open metallic grooves is investigated in this work. Three grooves with different depths but the same width were tested; for each groove, a gently deposited liquid droplet serves as the reservoir for liquid penetration. High-speed imaging revealed that, after the initial stage, the penetration in the grooves is in direct proportion to the square root of time and...
Leadfree solders have been used as interconnects in electronic packaging, due to its environmental friendly chemical property. However, those materials may experience high strain rates when subjected to shock and vibration. Consequently, failure will occur to electronics in those situations. Therefore, knowing the material properties of lead-free solders are extremely important, but research on mechanical...
Flip chip technology has attracted much attention in electronic industry as it fills the need for low cost, miniaturization and high performance requirements of electronic products. For such devices, package reliability under drop impact is a great concern to the manufacturers as these electronic packages are very much vulnerable to solder joint failures caused by the mechanical shock and the PCB...
Jet impingement cooling with phase change is a technique that has been successfully used to dissipate high heat fluxes (of order of 100 W/cm2 and higher) from advanced electronics. This work reports high speed visualization of jet impingement boiling on a copper heat spreader with porous coating. The coolant used in the experiments is a dielectric fluid, HFE-7100, in combination with a 5 × 5 array...
Data centers are mission-critical facilities and the nerve center of successful business operations. Surging demand for processing power, work load virtualization and consolidation is increasing data center heat loads, making the thermal management of data centers challenging. Containing the air in a data center is an important energy savings strategy towards data center optimization. Most of the...
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