bluuebunny/crossref_metadata_2025 huggingface dataset:
John Dewey's “Wholly Original Philosophy” and Its Significance for Museums
Authors: Hein George E.
Published: January 2010

Abstract  John Dewey's lifework was to create a philosophy that encompassed both life‐experience and thought. He attempted to construct a philosophical system that incorporated life as it is lived, not in some ideal form. He rejected all dualisms, such as those between thought and action, fine and applied arts, or stimulus and response. An analysis of “experience” (defined as almost synonymous with “culture”) is central to Dewey's writing and leads him to emphasize process, continuity, and development, rather than static, absolute concepts. This paper examines the significance of Dewey's educational views for museum exhibitions and education programs, and his complex definitions of relevant concepts, with special emphasis on his interpretation of “experience.” Dewey's faith in democracy and his moral philosophy require that the value of any educational activity depends on its social consequences as well as its intellectual content, a proposition that is discussed and applied to museums. This argument suggests that exhibitions and programs can strengthen democracy by promoting skills that improve visitors' ability to become critical thinkers and by directly addressing controversial issues, taking the side of social justice and democracy.
A Journey Unlike Any Other: An Interactive Exhibition at the National Museum in Copenhagen, Denmark
Authors: Funch Bjarne Sode
Published: January 2010

Abstract  A Journey Unlike Any Other is an interactive museum exhibition that introduces visitors to the experience of being a refugee. First, the visitor is confronted with hostility from soldiers in the homeland, and later, after an escape, with all the difficulties derived from meetings with police and immigration authorities in the new country. The provocations visitors endure during the course of the exhibition enhance a high degree of perceptual awareness, reflectivity and memory. In the aftermath of their experience, visitors indicate an increase of empathic understanding and experiential knowledge, whereas their interest in information and further background knowledge seems to be unaffected.
Building Relationships through Communities of Practice: Museums and Indigenous People
Authors: Kelly Lynda , Cook Carolyn , Gordon Phil
Published: January 2010

Abstract  This paper explores the theory of “communities of practice” and how the ideas contained in it could be applied to museums, by demonstrating how a key stakeholder group, Indigenous people, have been involved with and engaged in the work of the Australian Museum, Sydney, over the past 30 years. It is suggested that the processes museums have developed in building relationships with Indigenous people, particularly at the practitioner level, could form a template for how museums make themselves relevant to broader communities through active engagement with multiple communities of practice.
Grandparents Speak: Museum Conversations across the Generations
Authors: Leinhardt Gaea , Knutson Karen
Published: January 2010

Abstract  The research results from the Museum Learning Collaborative (MLC) indicate that learning in museums (defined as conversational elaboration) is strongly influenced by three factors: 1) the learning environment (defined as the response to large design features); 2) conversational engagement (defined as explanatory, analytic and synthetic discussions of objects); 3) group identity (defined as knowledge, experience, and motivation). These results were consistent across different museum types and different visiting populations (Leinhardt and Knutson 2004). This case study uses the experiences and conversations of one group—four members of an intergenerational grandparent‐grandchild group—and one dimension of the model: identity. It examines how this particular group of grandparents used the museum setting to take on diverse roles in ways that reflected identities: the role of storyteller (a sharer of information and family knowledge); the role of playmate (a learner and teacher who can enjoy an environment); the role of modeler of caring social interactions (a harmonizer who can experience conversational coherence and dissonance with grace). The conversational segments reproduced here are a means of unpacking the MLC model and exploring the discourse behaviors of this particularly interesting group.
Books
Authors: Linett Peter
Published: January 2010

Civilizing the Museum: The Collected Writings of Elaine Heumann Gurian: Elaine Heumann Gurian

London and New York: Routledge, 2006. Paperback, 208 pages. $35.95
Learning for Fun: The Unique Contribution of Educational Leisure Experiences
Authors: Packer Jan
Published: January 2010

Abstract  What do visitors want or expect from an educational leisure activity such as a visit to a museum, zoo, aquarium or other such experience? Is it to learn something or to experience learning? This paper uses the term “learning for fun” to refer to the phenomenon in which visitors engage in a learning experience because they value and enjoy the process of learning itself. Five propositions regarding the nature of learning for fun are discussed, drawing on quantitative and qualitative data from visitors to a range of educational leisure activities. The commonalities between learning for fun and other theoretical constructs such as “experience,” “flow,” “intrinsic motivation,” and “curiosity” are explored. It is concluded that learning for fun is a unique and distinctive offering of educational leisure experiences, with implications for future research and experience design.
“Let's Go to MY Museum”: Inspiring Confident Learners and Museum Explorers at Children's Museums
Authors: Enseki Carol
Published: January 2010

Abstract  Not a month goes by at the Brooklyn Children's Museum without a call or visit from a group of enthusiastic educators and community leaders on a mission to start their own children's museum or gallery. Recent guests have arrived from as far away as Israel, Ecuador, Japan, and Australia, and as nearby as the Bronx. In the United States, children's museums represent one of the youngest and fastest growing cultural sectors. Our field was founded in 1899 with the opening of the Brooklyn Children's Museum. Anna Billings Gallup, an influential curator and director at the museum from 1902 to 1937, spoke widely about the value of bringing the child into the forefront of museum activities. In the United States, the field grew slowly but steadily to four children's museums in 1925 and to approximately 38 by 1975. In the last three decades, sparked by the groundbreaking work of Michael Spock at the Boston Children's Museum, the field has been energized by an extraordinary boom in new and expanding children's museums. Today there are approximately 350 worldwide.
The Extraordinary Growth of the Science‐Technology Museum
Authors: Friedman Alan J.
Published: January 2010

Abstract  Science museums, coming off a period of 50 years of explosive growth, have been undergoing evolutionary development for over 200 years. Examples of three distinct generations thrive today, though hybrids are also common. The Science Museum in London is about half interactives; the Lawrence Hall of Science is known at least as much for its curriculum development as for its exhibitions; and the Exploratorium has built a large presence on the World Wide Web and in cities around the world. The evolution is continuing, but where is it going? Are science museums merging into one species, at last? Or are they diverging into many more categories, including virtual institutions with no physical collections at all?
Children's Museums as Citizens: Four Inspiring Examples
Authors: Monahan Peggy
Published: January 2010

Abstract  The audience‐centered mission of childrens' museums has caused these institutions to look at their role in their respective communities and to take bold steps in envisioning new ways of relating to their constituents. Here is a selection of four childrens' museums which have founded inspiring and imaginative programs centered on children's welfare.
On the Uses of Museum Studies Literature: A Research Agenda
Authors: Rounds Jay
Published: January 2010

Abstract  Preliminary evidence suggests that as few as 1,000 readers are attentive consumers of the museum studies literature. Does this suffice to ensure that the field is benefiting appropriately from its investment in research and theory development? Four complementary research strategies are proposed for studying the relationships between museum professionals and published research.
Fifty Years of Changes in America's History Museums
Authors: Sullivan Martin E.
Published: January 2010

Abstract  History museums in the U.S. have become significantly more professional over the past five decades. Many can boast of new and expanded buildings, improvements in collection management and care, and better‐trained staff and volunteers. However, most museums struggle with long‐term stagnation in audience numbers and revenues. The greatest challenge may be an alarming decline in American historical literacy and civic responsibility, especially at the elementary and secondary school levels. This article examines three trends that are affecting both the strengths and weaknesses of history museums today: the emergence of federal support, regulation, and oversight; a more inclusive approach to interpretation of the American past; and the all‐pervasive impact of information technology on both institutions and audiences.
Thinking about “Scenes”: A New View of Visitors' Influence on Museums
Authors: Kirchberg Volker
Published: January 2010

Abstract  Sociologists have described “scenes” as voluntary social groupings or figurations that are “… thematically focused cultural networks of people who share certain material and/or cognitive forms of collective stylization,” according to Hitzler, Bucher, and Niederbacher (2001, 20). This terminology is quite useful for thinking about Stephen Weil's assertion that visitors play a role in shaping museums. Through “scenes,” we see how this might happen, and how visitors might already be exerting subtle pressure on the forms and contents of museums. The study of scenes could help us develop a tool that would offer a unique vision of the influences that visitors have on museums.
Observing Panda Play: Implications for Zoo Programming and Conservation Efforts
Authors: Bexell Sarah M. , Jarrett Olga S. , Lan Luo , Yan Hu , Sandhaus Estelle A. , Zhihe Zhang , Maple Terry L.
Published: January 2010

Abstract  This study explores the effects of visitor observation of giant panda play on visitor concern for endangered species and satisfaction with seeing giant pandas. A total of 335 visitors to three institutions that house giant pandas participated in the study. These institutions are: the Chengdu Research Base of giant Panda Breeding, and the Chengdu Zoo, in China; and Zoo Atlanta in the U.S. After viewing the giant pandas, visitors were interviewed on whether they ever observed a panda play session, whether they observed panda play on the day of the visit, whether they wanted additional information on panda protection, and how satisfied they were with their visit to the pandas. An informational flyer was given to each interested survey participant after the interview. Visitors did not differ in their request for conservation information according to whether they had ever seen pandas play. However, visitors who observed panda play on the day of their visit expressed greater satisfaction with their visit. Implications for zoos and their conservation efforts are discussed.
Kelvingrove: Telling Stories in a Treasured Old/New Museum
Authors: O'Neill Mark
Published: January 2010

“Welcome to the future of museums” is one of the many rave head‐lines that greeted the reopening of Kelvingrove Art Gallery and Museum in Glasgow, Scotland, after a $60 (£30) million refurbishment. This article charts the course of the project over the 16 years it was in development, tells how it survived a number of major setbacks, and recounts the key strategic decisions that led to the creation of an object‐based, visitor‐centered, storytelling museum that was more successful than we dared hope. The project team aimed to integrate the demands of research, design, conservation, education, and communication in order to bring visitors and objects—in all their richness and complexity—into meaningful contact. This process has been rewarded with unprecedented visitor numbers‐3,000,000 in the first year, in a city of 600,000 people.
Small Wonder: Using SEM Images to Exhibit the “Small Stuff”
Authors: Beaudoin Alwynne B.
Published: January 2010

Abstract  Digital image enlargements can be a powerful method for displaying small specimens in museums. In 2007, the Royal Alberta Museum held an exhibition of 28 SEM (scanning electron microscope) images of seeds and other subfossil macroremains, which were shown in a fine‐art format. The exhibition was prepared by a museum team using images derived from in‐house curatorial research work. This paper describes the exhibition components and reports on an attempt to engage the visitors more closely with the images by asking them to suggest identifications for some “mystery” specimens.
Rethinking Museum Visitors: Using K‐means Cluster Analysis to Explore a Museum's Audience
Authors: Krantz Amanda , Korn Randi , Menninger Margaret
Published: January 2010

Abstract  Understanding visitors is a necessary and complex undertaking. In this article, we present K‐means cluster analysis as one strategy that is particularly useful in unpacking the complex nature of museum visitors. Three questions organize the article and are as follows: 1) What is K‐means cluster analysis? 2) How is K‐means cluster analysis conducted? 3) Most importantly: What are the applications of K‐means cluster analysis for museum practitioners? To answer these questions, we present five steps that are vital to conducting a K‐means cluster analysis. We also present three cases studies to demonstrate differences among the results of three K‐means cluster analyses and provide practical applications of the findings.
Books
Authors: Di Giovine Michael A.
Published: January 2010

Return to Alexandria: An Ethnography of Cultural Heritage Revivalism and Museum Memory, Michael A. Di Giovine
Development of New Power MOSFETs Package With Double-Sided Cooling
Authors: Ashida Kisho , Muto Akira , Shimizu Ichio , Kawano Kenya , Tanaka Naotaka , Yoneda Nae
Published: January 2010

We developed a new packaging technology, one that uses double-sided cooling to dramatically reduce the on-resistance and thermal resistance. The main features of this technology are as follows. Both sides of the chip are soldered to copper leadframes. After that, copper leadframes soldered to the top and bottom of the chip are exposed when transfer molding encapsulates the package. There were two development problems with packaging technology. The first is how to prevent chip crack in the reflow process. The second is how to improve the fatigue life of solder during the temperature cycling. To solve these problems, we designed our package structure using an experimental design method. In particular, for the second problem, we quantitatively calculated the amount of solder fatigue fracture and the number of cycles using the solder crack propagation analysis method, because the performance of the package depends on the amount of solder fatigue fracture. As a result, we could create a condition that prevented chip crack and improved the fatigue life of solder by the twice compared to the first prototype and determined the optimum structure. We assembled a new package based on this optimum structure, and confirmed this improvement of the reliability. In addition, we measured the on-resistance and thermal resistance of this package and that of the existing package available. We found that the new package’s on-resistance and thermal resistance decreased to about 70 and 80% that of the existing package respectively.
Thermal Conductivity and Contact Resistance Measurements for Adhesives
Authors: Teertstra Peter
Published: January 2010

Thermal adhesives that contain large concentrations of high thermal conductivity filler materials, such as ceramics or metals, are widely used by the electronics industries in a variety of applications. The thermal properties of these materials, such as the thermal contact resistance across a bonded joint and the thermal conductivity of the bulk material, are critical to the selection of the “best” material. A method is presented for the measurement of these thermal properties using a steady-state, guarded heat flux meter test apparatus based on the well-documented and familiar ASTM test standard D-5470. Five different adhesive materials are tested and a linear fit of the resulting resistance versus thickness data are used to determine the bulk thermal conductivity and contact resistance values. Four of the five materials tested had conductivity values of less than 1 W/mK, and the data demonstrates that a small but significant thermal contact resistance exists between the adhesive and the substrate for each of the adhesives.
Thermal Reliability and Environmental Testing of Advanced Metal Diamond Composites
Authors: Bollina Ravi , Landgraf Janet , Wagner Hannes , Wilhelm Robert , Knippscheer Sven , Mitic Gerhard , Levchuck Svetlana
Published: January 2010

Advanced diamond composites with matrix metal silver, copper and aluminum alloys were developed for heat sinks and base plates in high performance electronic packages. The reliability of these composites under extreme thermal and environmental conditions was investigated in the thermal cycling and pressure cooker tests. Thermal cycling tests on metal diamond composites were performed in a two chamber cycling oven between −55°C and +150°C for 1000 thermal cycles with 20 minutes storage time in each chamber. The effect of humidity and pressure was assessed from pressure cooker test at 121°C at 2 bar for 168 h. Thermal properties such as thermal diffusivity and specific heat were measured before and after the thermal cycling to observe any changes in thermal properties of the composites due to any possible interfacial degradation. The thermal properties of the composites did not decrease and the interfaces did not degrade after the thermal cycling tests in case of Ag-diamond composites. Al-diamond composites show a slight decrease of 5–8% in thermal diffusivity after thermal cycling. The thermal diffusivity of the Cu/Cr based diamond composite is unaltered before and after testing. The thermal diffusivity of Cu/Si diamond composites decreased by 43% at room temperature measured value. Al-diamond composites did not show any degradation during the pressure cooker tests although aluminum carbide is hygroscopic and deteriorates under moisture. Ag and Al-diamond composites survived the pressure cooker test. Cu/Si and Cu/Cr based diamond composites showed a slight change in coloration and a possible corrosion after the pressure cooker test.
Wiresweep Reduction via Direct Cavity Injection During Encapsulation of Stacked Chip-Scale Packages
Authors: Brand Jason M. , Ruggero Salvatore A. , Shah Amip J.
Published: January 2010

As packaging continues to offer challenges with variable stacked die configurations of increasing complexity, traditional transfer mold encapsulation faces challenges in defining a robust process window. A major concern is the problem of “wiresweep”, wherein deformation of the wirebond during the mold process can potentially cause short-circuiting. Several prior studies have focused on qualifying the effects of various wirebond and mold process parameters on package wiresweep, but most of these studies are restricted to single (discrete) die packages. This paper attempts to fill this gap-of-knowledge by experimenting with a variety of test vehicles with different stacking configurations. Specifically, the effects of varying loop height, stack height and mold compound type are quantified in terms of maximum wiresweep. We find that loop height can have a considerable effect on wiresweep, with the maximum wiresweep being reduced by half (from around 6% to less than 3%) simply by reducing the loop height. Additionally, the study finds that for a given mold process, higher die stacks tend to increase wiresweep, although a threshold stack height exists beyond which further stacking can reduce wiresweep. Lastly, the data suggest that the choice of mold compound can adversely impact wiresweep, especially for test vehicles with traditionally high wiresweep. Having identified these trends, semi-analytical models from the literature are used to investigate the cause behind these observations. The analysis suggests that the mold front velocity has the major root impact on package wiresweep. To validate this hypothesis, the series of tests conducted earlier is repeated for a compression mold process which provides greater control over the mold front velocity. As predicted by the model, significant reduction in wiresweep is achieved. Thus, the compression mold process seems to offer the opportunity for reducing wiresweep without any compromise in the complexity of the die stack.
Characterization of the Piezoresistive Coefficients of (100) Silicon From −150 to +125C
Authors: Cho Chun-Hyung , Jaeger Richard C. , Suhling Jeffrey C.
Published: January 2010

Stress sensing test chips are widely utilized to investigate integrated circuit die stresses arising from assembly and packaging operations. The test chips incorporate resistor or transistor sensing elements that are able to measure stresses by observing the changes in their resistivity or carrier mobility. This piezoresistive behavior of such sensors is characterized by three piezoresistive coefficients, which are electro-mechanical material constants. We are interested in stress characterization over a very broad range of temperatures. However, the literature provides limited data over the desired range, and even the data at room temperature, exhibit wide discrepancies in magnitude as well as sign. This work focuses on an extensive experimental study of the temperature dependence of the piezoresistive coefficients, π11, π12, and π44, for both p- and n-type silicon. In order to minimize errors associated with misalignment with the crystallographic axes on (100) silicon wafers, anisotropic wet etching was used in this work to accurately locate the axes. A special four-point bending apparatus has been constructed and integrated into an environmental chamber capable of temperatures from −155 to +300°C. Experimental calibration results for the piezoresistive coefficients as a function of temperature from −150°C to +125°C are presented and compared and contrasted with existing values from literature. Measurements were performed using stress sensors fabricated on (100) silicon mounted on PCB material including both die-on-beam and strip-on-beam mounting techniques. Four-point bending (4PB) was used to generate the required stress, and finite element simulations have been used to determine the actual states of stress in the silicon material.
Study of Printed Circuit Board Shock Transmissibility
Authors: Wang Frank Fan
Published: January 2010

It is always a challenge to deal with dynamic loads. Often, attempts are made to compare the peak acceleration of the shock load. However, the peak acceleration is the maximum acceleration at one frequency. It may not be the most damaging load for the electronics with a different resonant frequency. This paper is to propose a mathematical method to calculate printed circuit board deflections under shock load. The theory is the printed circuit board will deflect the most at its resonance point when there are dynamic excitations. This paper also discusses a method to use load factor or equivalent acceleration load to calculate printed circuit board deflections under dynamic loads.
Boiling Characteristics of Refrigerant Mixture Flow in Micro Scale Heat Exchangers Enhanced With Micro-Coils
Authors: Shariff Yasir M.
Published: January 2010

Flow in three horizontal channels for subcooled and saturated boiling characteristics are reported in this study. An experimental setup composed of heating elements provided heat flux variations on the channels. The heat transfer coefficient was found to be dependent on both the heat flux as well as mass flux levels. Results show that micro-coil inserts enhanced the heat transfer performance over that in smooth channels by 25% as compared to correlations for wire-coil inserts and 30% as compared to correlation for convective boiling process.
Circuit Connection Reliability Analysis of Laser-Drilled Blind Via Holes Using Data-Mining Method
Authors: Ogawa Keiji , Hirogaki Toshiki , Aoyama Eiichi , Nakagawa Heisaburo
Published: January 2010

The purpose of the present study is to analyze the circuit connection reliability of printed wiring boards (PWBs) with respect to thermal stresses on drilled hole walls. Micro-via drilling using laser technology has become the predominant method of machining smaller blind via holes. Moreover, a technique that uses copper foil in forming the circuit has been considered as a means of limiting the hole depth more accurately. After forming the blind via holes, copper plating must be used in order to maintain high reliability in circuit interconnectivity. In the present study, using the finite element method (FEM), we evaluated the effects of both the shape of the holes and the thickness of the copper plating on thermal stress occurring at the hole bottom. However, numerous factors are associated with the thermal stress, making the proper material composition and hole shape design difficult to determine. FEM must be applied to large amounts of data in order to identify quantitative tendencies. In addition, we applied a data-mining method to the thermal stress data, in an attempt to elucidate the factors that influence the reliability of blind via holes. The data-mining method revealed new factors that were hidden in the data; notably, the coefficient of thermal expansion in the thickness direction, despite the presence of other complex factors.
The Adiabatic Conditions on Inner Boundary for Natural Convection With Porous Medium in a Narrow Horizontal Cylindrical Annulus
Authors: Mansour Kamyar
Published: January 2010

We consider the two-dimensional problem of steady natural convection in a narrow Horizontal Cylindrical annulus filled with porous medium due to a cosine temperature variation on the outer and adiabatic conditions at the inner boundaries The solution is expanded in powers of a single combined similarity parameter, which is the product of the Gap ratio to the power of two and Rayleigh number and the series extended by means of symbolic calculation up to 28 terms. Analysis of these expansions allows the exact computation for arbitrarily accuracy up to 50000 figures. Although the range of the radius of convergence is small but Pade approximation leads our result to be good even for much higher value of the similarity parameter.
A PCM-Filled Heat Sink for an LED-Based Dental Device
Authors: Shabany Younes , Rose Eric P.
Published: January 2010

A new heat sink has been designed that increases the run time of a cavity-filling resin-curing or teeth-bleaching dental device with light emitting diode. The heat sink is a hollowed copper object that is filled with a phase change material. Computational simulations and experimental measurements are presented that show the heat sink with phase change material increases the run time of the device beyond the minimum requirement of six minutes.
Heat Transfer Analysis and Design Optimization of ALOX High Brightness Light Emitting Diode Package
Authors: Gao Shan , Hong Jupyo , Choi Sanghyun , Choi Seogmoon , Yi Sung
Published: January 2010

High Brightness (HB) Light emitting diode (LED) technology is becoming the choice for many lighting applications. However, one potential problem with LED based lighting systems is the thermal issue during service, which has restricted LED in the application of mini-devices. In this study, thermal performance of Al2O3 (ALOX) based HBLED package is considered. Steady state heat transfer analysis is carried out using 3-D finite element method (FEM). A new algorithm has firstly been developed, which combines FEM analysis and thermal transient experimental investigation, to determine the interfacial thermal properties of the package. Then the interfacial thermal properties are applied in the FEM model for heat transfer analysis. Temperature distribution and heat flux analysis are calculated and thermal resistance of the package is determined based on the FEM simulation. The results show that die attachment (solder material) plays the most important role in the thermal resistance of the ALOX package, i.e., it takes about 80% of the total thermal resistance. In addition, thermal resistance of the package is mainly caused by the interfacial thermal resistances, the behavior of which depends strongly on manufacturing processes. The parametric study shows that Al2O3 isolation ring increases the thermal resistance of the package because it creates an interface inside the aluminum substrate. Pure Aluminum substrate achieves a better performance in the respect of thermal behavior of packaging designs.
Analytical Solution of Whispering-Gallery Modes
Authors: Quan Haiyong , Guo Zhixiong
Published: January 2010

Advances in MEMS/NEMS techniques have enabled high-Q whispering-gallery modes in integrated microcavities. Potential applications of optical microcavities include quantum informatics, novel micro/nano sources, dynamic filters, and micro/nanosensors. It is important to understand the intrinsic resonant modes of a cavity. In this report, we will analyze whispering-gallery modes in resonators of planar structure which is common in MEMS devices. The wave equation is solved by using the method of separation of variables with appropriate boundary conditions. Analytical formulations are established. The resonance frequencies as well as the electric field distributions in exemplary resonators are presented for a variety of whispering-gallery modes.
Advanced Thermal-Moisture Analogy Scheme for Anisothermal Moisture Diffusion Problem
Authors: Jang Changsoo , Han Bongtae , Park Seungbae , Yoon Samson
Published: January 2010

We propose an advanced thermal-moisture analogy scheme to cope with the inherent limitations of the existing schemes. The new scheme is based on the experimentally-observed unique hygroscopic behavior of polymeric materials used in microelectronics; i.e., the saturated concentration is only a function of relative humidity regardless of temperature. A new analogy formulation based on the modified solubility is presented and the scheme is implemented to investigate its accuracy and applicability. The results from a simple case study corroborate that the advanced scheme can be used effectively for package assemblies subjected to general anisothermal loading conditions.
In-Situ Evaluation of High Frequency and High Temperature Characteristics of Dielectric in High-Density Substrate
Authors: Wu Youhong , Kato Shinobu , Wang DongDong , Matsuoka Toshimasa , Taniguchi Kenji
Published: January 2010

To design a high-speed/frequency system, the dielectric material properties, i.e., dielectric constant and loss tangent are key inputs and their frequency and temperature dependency need to be “in situ” comprehended accurately, since important high-speed quantities, such as characteristic impedance, propagation constant and S-parameters, depend upon the physical dimensions and dielectric material properties of transmission line. This paper investigates frequency and temperature dependent properties of dielectric materials used for high performance microelectronic substrate up to 40 GHz under −40 to 200 deg C, with a general-purpose vector network analyzer (VNA) for obtaining S-parameter of “in situ” test coupons fabricated utilizing the actual process technology. Based on this “in situ” measurement, impact of the frequency and temperature dependent dielectric material properties on the high-speed quantities also have been discussed.
Perspiration Nano-Patch for Hot Spot Thermal Management
Authors: Narayanan Shankar , Fedorov Andrei G. , Joshi Yogendra K.
Published: January 2010

A novel cooling scheme utilizing evaporative cooling for an ultra-thin, spatially confined liquid film is described for meeting the challenge of hot spot thermal management aiming at locally removing heat fluxes in excess of 200 W/cm2. This work presents the conceptual system design and results of performance calculations supporting the feasibility of the proposed cooling scheme. The phase change heat transfer is one of the most efficient means of heat transfer due to an advantage offered by the significant latent heat of vaporization of liquids. Fundamentally, evaporation could be a much more efficient method of heat removal as compared to boiling if certain conditions are met. Theoretically, we demonstrate that if a stable monolayer of liquid can be maintained on the surface and fully dry sweeping gas (e.g., air) is blown at high velocity above this liquid monolayer one can dissipate heat fluxes of the order of several hundreds of Watts per cm2. We also show that a more volatile FC-72 can outperform water in evaporative cooling using stable liquid microfilms.
Dynamic Characteristics of the Capillary Pumped Loop for Cooling the Tower-Type Computer
Authors: Tsujimori Atsushi , Kato Masashi , Uchida Maiko
Published: January 2010

Capillary pumped loop has been widely investigated for space thermal control devices. This cooling device with high reliability and thermal controllability is also considered to be suited to cool electronic devices like personal computers. Because the capillary pumped loop is good at absorbing heat from high heat flux region like micro-processors, transporting it and releasing it from the large surface for packaging. In this research, the experimental equipment of the capillary pumped loop was manufactured. The experimental apparatus consists of the evaporator, the condenser, the liquid line, the vapor line and the reservoir. In the experiments heat load is applied to the evaporator by a resistance heater. And heat is released from the condenser to the cooling water which is set to be a constant temperature by the refrigerator. The length and the diameter of the evaporator are 150mm and 27mm respectively and the capillary wick with equivalent diameter of 5μm is embedded in the evaporator. These specifications were designed to give 2500mm heat transport distance and to adapt the natural convection heat transfer to the ambient without a cooling fan. As is proposed in the recent study, the inside of the capillary wick was used as the reservoir to simplify the loop. In our previous study, the heat transport characteristics in steady states were investigated when the heat flux, the cooling water temperature and the evaporator height above the condenser changed, and then the effects of enclosed rate of the working fluid in the reservoir and the inclination angles of the evaporator on heat transport rate were investigated. The computer code was also developed to simulate the heat transport characteristics and evaluate the maximum heat transport rate of the tested capillary pump. In the next step, we focus on the dynamic characteristics. The heat loads of the micro-processors in the computers usually change according to the working conditions of the application software and vary hourly. Thus the active thermal regulation accompanied with the change of heat loads is the important factor for cooling devices in the computers. So in this study the heat transport characteristics in the dynamic conditions of the capillary pumped loop were investigated. In the experiment, the start-up and shut-down mode at a given heat load were tested at first. Then heat load were changed in incremental or decremental steps from 30 to 70W. All results show the good thermal controllability.
Nondestructive Measurement of C4 BLM Undercut by Scanning Acoustic Microscope
Authors: Lu Minhua , Bailey Carla , Liu Hsichang , Semkow Krystyna
Published: January 2010

A non-destructive measurement of ball limiting metallurgy (BLM) undercut is demonstrated by using C-mode scanning acoustic microscopy. The results from CSAM measurements agree well with the optical and cross-section data. The implementation of the method in manufacturing will not only save time and cost on destructive failure analysis such as cross section and chemical un-layering, but also provide a way for monitoring process trend for early detection and correction of process abnormalities.
Interaction of Synthetic Jet Cooling Performance With Gravity and Buoyancy Driven Flows
Authors: Arik Mehmet , Utturkar Yogen , Gursoy Mustafa
Published: January 2010

Meso scale cooling devices have been of interest for low form factor, tight space, and high COP thermal management problems. A candidate meso scale device, known as synthetic jets, operates with micro fluidic principles and disturbs the boundary layer causing significant heat transfer over conventional free convective heat transfer in air. Previous papers have dealt with the impingement and cross flow, but did not study mixed convection for synthetic jet with natural convection. In the present study, we discuss the results of an experimental study to investigate the interplay between jet orientations with respect to gravity, elevated temperature conditions, and synthetic jet heat dissipation capacity. Experiments were performed by placing synthetic at different positions around a square, 25.4mm heated flat surface. The flow physics behind the experimental findings is discussed. It is found that impingement heat transfer outperformed more than 30% compared to other orientations. The jet showed about 15% sensitivity to angular orientations.
Influence of Cu Surface Treatment on the Cu-Direct Via Hole Drilling Efficiency of PWBs
Authors: Hirogaki Toshiki , Aoyama Eiichi , Ogawa Keiji , Matsutani Shogo
Published: January 2010

This report describes the quality assessment of blind via holes (BVHs) of Printed Wiring Boards (PWBs) drilled by a CO2 laser using Cu-direct drilling. In the Cu-direct drilling method, the copper foil and the buildup layer are melted at the same time, and the surface is treated to increase the laser energy absorbed by the copper foil because an untreated copper surface reflects most of the 10.6-μm-wavelength CO2 laser beam. We used black-oxide and V-bond treatments as surface treatment. Previously, the only black-oxide treatment was paid attention to, but the new V-bond treatment is also investigated in this report. First, a straightforward method employing infrared thermography was proposed to determine the absorbance of the CO2 laser beam by the copper surface. Then, we used SEM to characterize the copper surfaces after surface treatment, and established the relationship between laser absorbance and surface shape. Subsequently, we observed the circumference of a point irradiated with the CO2 laser and explained melting processes were different from surface shape. Finally, we investigated the relationship between laser absorbance and BVH quality, and showed that a high absorbance improved BVH quality.
Forming High Temperature Solder Interfaces by Low Temperature Fluxless Processing
Authors: Lu Daoqiang Daniel , Hu Chuan , Huang Annie Tzu-Yu
Published: January 2010

This paper provides a fundamental study of large area, fluxless bonding with three different solder systems Cu-Sn, Ag-In, and Ag-SnBi, which were pre-deposited in layered structures. The thickness of each individual layer was carefully designed such that, after bonding and annealing at lower temperatures, the final solder interface only had high melting point components and showed higher re-melting points. A systematic bonding study was conducted, and re-melting points and microstructure of the formed solder interface were studied using differential scanning calorimetry (DSC), and scanning electron microsopy (SEM), respectively.
On the Multiscale Finite Element Analysis for Interfacial Fracture in Cu/Low-K Interconnects
Authors: Chiu Tz-Cheng , Lin Huang-Chun
Published: January 2010

The interface crack problem in integrated circuit devices was considered by using global and local modeling approach. In the global analysis the thin film interconnect was modeled by a homogenized layer with material constants obtained from representative volume element (RVE) analysis. Local analyses were then considered to determine fracture mechanics parameters. It was shown that the multiscale model with RVE approach gives accurate fracture mechanics parameters for an interface crack under either thermal or mechanical loads; while significant error was observed when the thin film layers are ignored in the global analysis. The problem of an interface crack between low-k dielectric and etch-stop thin film in a flip-chip package under thermal loading was also investigated as an application example of the multiscale modeling.
Characterization of Light Weight Heat Sink Materials for Thermal Management of Electronics
Authors: Icoz Tunc , Arik Mehmet , Dardis John T.
Published: January 2010

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.
Thermoelectric Cooler Based Regenerative Adsorption Refrigeration System for High Temperature Electronics
Authors: Sinha Ashish , Joshi Yogendra , Storm Bruce H.
Published: January 2010

This paper presents the analytical study of a thermoelectric cooler (TEC) based two-stage regenerative adsorption cycle with evaporator temperature ranging from 80°C to 180°C and heat rejection temperature ranging from 200°C to 230°C. This proposed cycle restricts the highest temperature at which the TEC regenerates heat by reducing the maximum bed temperature during the desorption phase, which leads to the possibility of the system being realized with commercially available TECs and a reasonable TEC coefficient of performance (COP∼ 0.4). The low COP (<1) of the TEC results in excess heat at the desorption bed during heat regeneration. If the excess heat is rejected to the environment, COP gains arising from regeneration are reduced. Using the TEC to regenerate only part of the heat helps to mitigate this problem. The adsorption cycle in conjunction with TEC can pump heat through larger temperature differences with system efficiency much greater than that of a TEC used alone under identical conditions. The study aims to extend the limits of the adsorption refrigeration systems to provide compact cooling devices for harsh environments.
A Mathematical Model Predicting Heat Transfer Performance in a Oscillating Heat Pipe
Authors: Ma H. B. , Borgmeyer B. , Cheng P. , Zhang Y.
Published: January 2010

A mathematical model predicting the oscillating motion in an oscillating heat pipe is developed. The model considers the vapor bubble as the gas spring for the oscillating motions including effects of operating temperature, non-linear vapor bulk modulus, and temperature difference between the evaporator and the condenser. Combining the oscillating motion predicted by the model, a mathematical model predicting the temperature drop between the evaporator and the condenser is developed including the effects of the forced convection heat transfer due to the oscillating motion, the confined evaporating heat transfer in the evaporating section, and the thin film condensation in the condensing section. In order to verify the mathematical model, an experimental investigation was conducted. Experimental results indicate that there exists an onset power input for the excitation of oscillating motions in an oscillating heat pipe, i.e., when the input power or the temperature difference from the evaporating section to the condensing section was higher than this onset value the oscillating motion started, resulting in an enhancement of the heat transfer in the pulsating heat pipe. Results of the investigation will assist in optimizing the heat transfer performance and provide a better understanding of heat transfer mechanisms occurring in the oscillating heat pipe.
Thermal Fatigue Life Determination of CCGA Interconnect Using a Simple Method
Authors: Wong T. E. , Chu C.
Published: January 2010

A simplified method was developed to determine the fatigue life of a ceramic column grid array (CCGA) solder joint when exposed to thermal environments. The CCGA package with 90Pb/10Sn solder columns is soldered onto the printed circuit board with a tin-lead solder paste. Failure of the solder joint occurs at the CCGA solder column. A closed-form solution with the equilibrium of displacements of electronic package assembly was first derived to calculate the solder joint strains during the temperature cycling. In the calculation, an iteration technique was used to obtain a convergent solution in the solder strains, and the elastic material properties were used for all the electronic package assembly components except for the solder materials, which used elastic-plastic properties. A fatigue life prediction model, evolved from an empirically derived formula based upon a modified Coffin-Manson fatigue theory, was then established. CCGA test results, obtained from various sources, combined with the derived solder strains were used to calibrate the proposed life prediction model. In the model calibration process, the 625- and 1657-pin CCGA test results, which were cycled between 20°C/90°C, 0°C/100°C, −55°C/110°C, or −55°C/125°C, were reasonably well correlated to the calculated values of solder strains. In addition, this calibrated model is remarkably simple compared to the model used in an evaluation by a finite element analysis. Therefore, this model could be used and is recommended to serve as an effective tool to make a preliminarily estimate at the CCGA solder joint thermal fatigue life. It is also recommended to 1) select more study cases with various solder joint configurations, package sizes, environmental profiles, etc. to further calibrate this life prediction model, 2) use this model to conduct parametric studies to identify critical factors impacting solder joint fatigue life and then seeking an optimum design, and 3) develop a similar life prediction model for lead-free solder materials.