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A holistic system-level analysis of the energy and mass transfer in a data center cooling system is used to determine the exergy destruction by each component in the system. The analysis, performed using our in-house analysis code, allows for identification of system inefficiencies and comparison of the energy efficiency of different data center cooling strategies. In this paper, we describe a systematic...
Solid-state lighting (SSL) products can have a predicted life of 70% lumen output (L70) from 26,000 to 40,000 hours using the LM-80-08 testing standards. Chromaticity shift, correlated color temperature (CCT) and lumen maintenance (LM) will dramatically reduce the nominal life of SSL luminaires. In this work, an off-the-shelf luminaire from Philips (AmbientLED) has been aged in a standard wet hot...
Analytical models of stress and deformxation of through-silicon vias (TSV), relative to numerical ones, have the advantage of being inexpensive to evaluate and in providing insight. They have the additional advantage of allowing one to embed them in ECAD tools for real time design decisions. Motivated by this reasoning, in this paper, an analytical model for the three-dimensional state of stress in...
Laminar mixed convection heat transfer in a two dimensional symmetrically and partially heated vertical channel is investigated. The heated portions exist on the both walls of channel and their temperature is constant. The number of the heated portions is changed from 2 to 4 for each wall; however the total length of the heated portions is fixed. The fluid inlet velocity is uniform and air is taken...
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...
With the decreasing sizes of transistors and the increasing integrated circuit (IC) density, heat dissipation can be a limiting factor in developing emerging semiconductor technologies, such as silicon-on-insulator (SOI) based transistors and 3D-stacked ICs. To overcome this challenge, accurate thermal simulations are needed. The goal of this investigation is to explore the use of proper orthogonal...
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,...
To keep up with the growing energy demand, legacy aircooled data centers have begun to implement simple but effective energy efficiency strategies or best practices. Improving “air management”, optimizing the delivery of cool air and the collection of waste heat, are among these efficiency strategies. One of the most powerful tools for identifying energy wasteful practices is the application of the...
In the electronic packaging industry, it is important to be able to make accurate predictions of board level solder joint reliability during thermal cycling exposures. The Anand viscoelastic constitutive model is often used to represent the material behavior of the solder in finite element simulations. This model is defined using nine material parameters, and the reliability prediction results are...
The transient behavior of IT equipment can be represented by a lumped thermal capacitance for use in data center level transient thermal simulations. Previous work has proposed a mathematical methodology to extract the necessary lumped capacitance parameters, the server's time constant and heat transfer effectiveness, via air temperature measurements. This work describes and experimentally tests that...
This paper describes the effect of cooling from a surface of power Si MOSFET on hot spot temperature. In traditional thermal design of electronics, the temperature distribution of chips is assumed to be uniform for simplicity of thermal design. However, in recent years, thermal problems of electronics are more serious, because electronics have been downsizing. Therefore, we should consider the temperature...
Operational expenses of servers and the data center to support them account for a significant part of the total cost of ownership of a data center and potentially the total business. Manipulating the inlet temperature to the servers can provide a possible method of lowering the operating cost of a data center. Conventional wisdom regarding management of the cold aisle temperature in the data center...
Compact thermal modeling of hand-held and ultra-low power microelectronic systems has recently attracted a great deal of attention. In this study time-dependent evolution of heat transfer around a flat plate was numerically investigated. The flat plate is subjected to internal heat generation from the inner boundary via a discrete heat source. It is cooled on the outer boundary via buoyancy and radiation...
Experimental testing and microstructural characterization have revealed that lead-free solders exhibit evolving properties that change significantly with environmental exposures such as isothermal aging and thermal cycling. These changes are especially large in harsh environments, where the effects of aging on solder joint behavior must be accounted for and included in constitutive models when predicting...
Lead free solder materials are widely used in electronic packaging industry due to environmental concerns. However, experimental testing and microstructural characterization have revealed that Pb-free solders exhibit evolving properties that change significantly with environmental exposures such as isothermal aging and thermal cycling. These changes are especially large in harsh environments, where...
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