scholarly journals The Effects of Inlet Blockage and Electrical Driving Mode on the Performance of a Needle-Ring Ionic Wind Pump

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 900
Author(s):  
Jia-Cheng Ye ◽  
Tsrong-Yi Wen
Keyword(s):  
Thermal Management ◽  
The Other ◽  
Constant Current ◽  
Ionic Wind ◽  
Viable Option ◽  
Driving Mode ◽  
Space Limit ◽  
Thermal Solution ◽  
Small Needle ◽  
Consistent Performance

The thermal management of microelectronics is important because overheating can lead to various reliability issues. The most common thermal solution used in microelectronics is forced convection, which is usually initiated and sustained by an airflow generator, such as rotary fans. However, traditional rotary fans might not be appropriate for microelectronics due to the space limit. The form factor of an ionic wind pump can be small and, thus, could play a role in the thermal management of microelectronics. This paper presents how the performance of a needle-ring ionic wind pump responds to inlet blockage in different electrical driving modes (direct current), including the flow rate, the corona power, and the energy efficiency. The results show that the performance of small needle-ring ionic wind pumps is sensitive to neither the inlet blockage nor the electrical driving mode, making needle-ring ionic wind pumps a viable option for microelectronics. On the other hand, it is preferable to drive needle-ring ionic wind pumps by a constant current if consistent performance is desired.

scholarly journals Notes on gravity multiplet correlators in AdS3 × S3

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Congkao Wen ◽  
Shun-Qing Zhang
Keyword(s):  
Recursion Relation ◽  
Conformal Symmetry ◽  
Flat Space ◽  
The Other ◽  
Tree Level ◽  
Space Limit ◽  
Compact Expression ◽  
Tensor Multiplet ◽  
R Symmetry

Abstract We present a compact formula in Mellin space for the four-point tree-level holographic correlators of chiral primary operators of arbitrary conformal weights in (2, 0) supergravity on AdS3× S3, with two operators in tensor multiplet and the other two in gravity multiplet. This is achieved by solving the recursion relation arising from a hidden six-dimensional conformal symmetry. We note the compact expression is obtained after carefully analysing the analytic structures of the correlators. Various limits of the correlators are studied, including the maximally R-symmetry violating limit and flat-space limit.

scholarly journals A Double Sky-Hook Algorithm for Improving Road-Holding Property in Semi-Active Suspension Systems for Application to In-Wheel Motor

2021 ◽  
Vol 11 (19) ◽  
pp. 8912
Author(s):  
Seunghoon Woo ◽  
Donghoon Shin
Keyword(s):  
Computer Simulations ◽  
Dynamic Models ◽  
Active Suspension ◽  
The Other ◽  
Driving Mode ◽  
The Road ◽  
Suspension Systems ◽  
Active Suspension Systems ◽  
Main Disadvantage ◽  
Advanced Development

This paper presents a double sky-hook algorithm for controlling semi-active suspension systems in order to improve road-holding property for application in an in-wheel motor. The main disadvantage of the in-wheel motor is the increase in unsprung masses, which increases after shaking of the wheel, so it has poor road-holding that the conventional theoretical sky-hook algorithm cannot achieve. The double sky-hook algorithm uses a combination of damper coefficients, one from the chassis motion and the other from the wheel motion. Computer simulations using a quarter and full car dynamic models with the road conditions specified by ISO2631 showed the effectiveness of the algorithm. It was observed that the algorithm was the most effective in the vicinity of the wheel hop frequency. This paper also proposed the parameter set of the double sky-hook algorithm to differentiate the driving mode of vehicles under advanced development.

Characterization of Light Weight Heat Sink Materials for Thermal Management of Electronics

2007 ◽  
Author(s):  
Tunc Icoz ◽  
Mehmet Arik ◽  
John T. Dardis
Keyword(s):  
Thermal Management ◽  
Heat Sink ◽  
High Efficiency ◽  
Computational Study ◽  
Heat Sinks ◽  
Advanced Materials ◽  
Air Cooling ◽  
Thermal Management Of Electronics ◽  
Thermal Solution

Thermal management of electronics is a critical part of maintaining high efficiency and reliability. Adequate cooling must be balanced with weight and volumetric requirements, especially for passive air-cooling solutions in electronics applications where space and weight are at a premium. It should be noted that there are systems where thermal solution takes more than 95% of the total weight of the system. Therefore, it is necessary to investigate and utilize advanced materials to design low weight and compact systems. Many of the advanced materials have anisotropic thermal properties and their performances depend strongly on taking advantage of superior properties in the desired directions. Therefore, control of thermal conductivity plays an important role in utilization of such materials for cooling applications. Because of the complexity introduced by anisotropic properties, thermal performances of advanced materials are yet to be fully understood. Present study is an experimental and computational study on characterization of thermal performances of advanced materials for heat sink applications. Numerical simulations and experiments are performed to characterize thermal performances of four different materials. An estimated weight savings in excess of 75% with lightweight materials are observed compared to the traditionally used heat sinks.

Thermal Management of Low Profile Applications

2007 ◽  
Author(s):  
Ed Walsh ◽  
Pat Walsh ◽  
Ronan Grimes ◽  
Vanessa Egan
Keyword(s):  
Thermal Management ◽  
Thermal Performance ◽  
Heat Sink ◽  
Optimal Solution ◽  
Battery Life ◽  
Heat Conducting ◽  
Pumping Power ◽  
Low Profile ◽  
Thermal Solution ◽  
Footprint Area

There is an increasing need for low profile thermal management solutions for applications in the range of five to ten watts targeted at portable electronic devices. This need is emerging due to enhanced power dissipation levels in portable electronics. This work focuses upon the optimization of such a solution within certain constraints of profile and footprint area. A number of fan geometries have been investigated where both the inlet and exit rotor angles are varied relative to the heat conducting fins on a heat sink. The ratio of fan diameter to heat sink fin length was also varied. The objective was to determine the optimal solution from a thermal management perspective within defined constraints. The results show good thermal performance for low profile thermal management solutions, and highlight the need to develop the heat sink and fan as an integrated thermal solution rather than in isolation as is the traditional methodology. It is also found that while increasing pumping power generally improves the thermal performance, only small gains are achieved for relatively large pumping power increases. This is important in optimizing portable systems which are powered by limited battery life.

Heat Pipe Optimization Team: The Heat Pipe Assisted Heat Sink Project

2004 ◽  
Author(s):  
Damena Agonafer ◽  
Juan Ibarra ◽  
Kendrick McGee ◽  
Frank Platt ◽  
Kendall Harris ◽  
...  
Keyword(s):  
Heat Pipe ◽  
Thermal Management ◽  
Heat Sink ◽  
Cell Phone ◽  
Transfer Cell ◽  
Customer Requirements ◽  
High Increase ◽  
Phone Calls ◽  
Thermal Solution ◽  
Base Transceiver Station

The Heat Pipe Assisted Heat Sink (HPAHS) team will be working on solving challenging thermal management problems for a device known as the base transceiver station (BTS); a device used to transfer cell phone calls. This problem was raised due to transfer cell phone calls. This problem was raised due to the high use of cell phone in recent years. According to 2002 Scarborough Research, the number of cell phones in US was 180 million (2/3 of population). Due to this high increase in demand for cell phone usage, Replacement Handset Shipments are projected to increase worldwide from Current 40% of total shipments to almost 85%. This will increase from 211 million in 2002 to 591 million by 2008 (Nokia). Cell phone calls are transferred via a device known as the base transceiver station (BTS). Cell phone companies are increasing the performance of the BTS by adding more electronics. Nokia is increasing the current BTS performance by adding another power amplifier. We will encounter the problem of designing the thermal solution to ensure optimal thermal performance, while meeting customer requirements of cost and manufacturing process.

Assessment of Some Integrated Cooling Mechanisms for an Active IPEM

2004 ◽  
Author(s):  
Y. Pang ◽  
E. Scott ◽  
J. D. van Wyk ◽  
Z. Liang
Keyword(s):  
Power Electronics ◽  
Thermal Management ◽  
Three Dimensional ◽  
The Other ◽  
Other Hand ◽  
3D Packaging ◽  
3D Package

With the growing demands on the performance, cost, and advances in packaging and interconnection technology, three-dimensional (3D) packaging provides higher density packaging. On the other hand, thermal management of the 3D package becomes a very important issue. This paper assesses the various possibilities of integrated thermal management for integrated power electronics modules (IPEMs).

Heat Conduction in Three Dimensional Stacked Packages

2005 ◽  
Author(s):  
Anand Desai ◽  
James Geer ◽  
Bahgat Sammakia
Keyword(s):  
Heat Conduction ◽  
Thermal Management ◽  
Heat Generation ◽  
Analytical Study ◽  
Three Dimensional ◽  
The Other ◽  
Heat Generation Rate ◽  
Potential Applications ◽  
Steady State Heat ◽  
Spatially Varying

This paper presents the results of an analytical study of steady state heat conduction in multiple rectangular domains. Any finite number of such domains may be considered in the current study. The thermal conductivity and thickness of these domains may be different. The entire geometry composed of these connected domains is considered as adiabatic on the lateral surfaces and can be subjected to uniform convective cooling at one end. The other end of the geometry may be adiabatic and a specified, spatially varying heat generation rate can be applied in each of the domains. The solutions are found to be in agreement with known solutions for simpler geometries. The analytical solution presented here is very general in that it takes into account the interface resistances between the layers. One application of this analytical study relates to the thermal management of a 3-D stack of devices and interconnect layers. Another possible application is to the study of hotspots in a chip stack with non uniform heat generation. Many other potential applications may also be simulated.

27. Choice of business medium

2018 ◽  
Author(s):  
J. Scott Slorach ◽  
Jason Ellis
Keyword(s):  
Social Security ◽  
Limited Liability ◽  
Capital Gains ◽  
The Other ◽  
Viable Option ◽  
Inheritance Tax ◽  
The One ◽  
Limited Liability Partnership ◽  
Business Media ◽  
Capital Expense

This chapter makes a comparison between companies, on the one hand, and partnerships or sole traders, on the other, in order to explain the various factors which should be taken into account when choosing the two business media. It considers factors such as risk of capital, expense, publicity, taxation, interest relief, capital gains, inheritance tax, pensions and social security Due to the range of variables, the desirability of limited liability means that incorporation may be the only viable option, although this can also be achieved by setting up a limited liability partnership. Where limited liability is not of great importance, the tax factors will be more significant and these would have to be examined from a number of perspectives, including the size of anticipated profits, the particular financial circumstances of the promoters of the business, and any particular expectations they had about their stake in the business.

Epithelial Insert Trial for Retention of Prosthetic Hair Replacement

1998 ◽  
Vol 15 (2) ◽  
pp. 151-154
Author(s):  
Anthony S. Pignataro
Keyword(s):  
Scalp Hair ◽  
The Other ◽  
Viable Option ◽  
Infectious Process ◽  
Future Studies ◽  
Pilot Hole ◽  
Dental Technology

Introduction: Success in the retention of prosthetic teeth has led the author to believe that dental technology could be applied to scalp hair retention. The question to be answered is, “Can epithelial inserts work for prosthetic hair replacement?” Material and Methods: One volunteer was utilized to test the epithelial insert for prosthetic hair replacement. A pilot hole was drilled into the scalp on each side. On one side, a 5-mm mucosal insert was used, and on the other side, a 9-mm mucosal insert that engaged the underlying bone was utilized. Results: Pain, inflammation, discharge, and induration occurred in both implants. The implants were removed at the end of 6 weeks; there was no maturation of either one. Discussion: At the present time, epithelial inserts for retention of prosthetic hair replacement are not a viable option. Perhaps future studies can be designed to prevent the inflammatory and infectious process.

Exergo-Thermo-Volumes: An Approach for Environmentally Sustainable Thermal Management of Energy Conversion Devices

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Amip J. Shah ◽  
Chandrakant D. Patel
Keyword(s):  
Thermal Management ◽  
Environmental Sustainability ◽  
Heat Removal ◽  
Electronic Cooling ◽  
Environmentally Sustainable ◽  
Energy Technologies ◽  
Removal Capacity ◽  
Efficient Management ◽  
Thermal Solution ◽  
Energy Conversion Devices

The design of cooling solutions is an important consideration for the efficient management of different types of energy technologies. In the present work, we adapt the method of thermo-volumes—which has been used for nearly a decade in the design of electronic cooling solutions—for purposes of expeditiously understanding the thermal resistance of a given solution (in terms of cooling performance) along with its flow resistance (an indicator of the pumping power or energy consumption, which will be required by the thermal solution). Furthermore, we expand on thermo-volumes by including the lifetime exergy cost as a means to enable the consideration of resource consumption (and thus the environmental sustainability) of the cooling solution. We apply this framework for evaluation of thermal management solutions in terms of the heat removal capacity per unit lifetime exergy consumption. This paper concludes by illustrating applicability of the method to the design of a fuel cell thermal management solution.

Sign in / Sign up

Export Citation Format

Share Document