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Thermal challenges in next-generation electronic systems, as identified through panel presentations and ensuing discussions at the workshop, Thermal Challenges in Next Generation Electronic Systems, held in Santa Fe, NM, January 7-10, 2007, are summarized in this paper. Diverse topics are covered, including electrothermal and multiphysics codesign of electronics, new and nanostructured materials, high heat flux thermal management, site-specific thermal management, thermal design of next-generation data centers, thermal challenges for military, automotive, and harsh environment electronic systems, progress and challenges in software tools, and advances in measurement and characterization. Barriers to further progress in each area that require the attention of the research community are identified.

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The recent emphasis on low-cost high-end servers and desktop workstations has resulted in a renewed interest in the development of high-performance air-cooled systems. A new generation of advanced heat sink designs capable of dissipating up to 105 W/m2 have been proposed and developed. Better manufacturing tolerances, lower defects, and an improved understanding of card and enclosure effects have been attained and shown to be critical to achieving the desired thermal performance. Advanced internal thermal enhancements, encompassing high thermal conductivity adhesives and greases have also been implemented. This review article covers recent developments in heat sink designs and applications intended for high-end high-power dissipation systems. A review of recent studies of card effects in the thermal enhancement of electronic packages is also presented. In certain applications the card heat-sinking effect can play a major role in the thermal management of a package, accounting for more than 50 percent of the total power dissipation of the package.

Conducting polymers can be tuned by manipulating the delocalized π electron system for chemical and electrocatalytic applications. We hereby describe the reduction of Cr(VI) to Cr(III) by flexible nanostructured conducting poly(amic acid) (PAA) in both solution phase and as a thin film on a gold electrode. Sodium borohydride was used as a reducing agent to prepare different sizes (3−20 nm) of palladium nanoparticles (PdNPs). The effects of experimental parameters such as particle size, temperature, and Cr(VI) concentration on the kinetics and efficiency of reduction process were investigated. Results show that in PAA solution, Cr(VI) was efficiently reduced by 85.9% within a concentration range of 1.0 × 10−1−1.0 × 102 mM. In the presence of PdNPs and heat (40 °C), the reduction efficiency increased to 96.6% and 99.9% respectively. When employed on a solid electrode, PAA undergoes a quasi-reversible electrochemistry in acidic media with reduction efficiency for Cr(VI) at 72.84%. The method was validated using both colorimetric and Electron Paramagnetic Resonance techniques, which confirmed the formation of Cr(III) as the product of catalytic reduction. Additional characterization conducted using transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) confirmed that there was no significant change in Pd particle size and distributions after dispersion in PAA whereas its phase and oxidation state remained unchanged. Electrochemical characterization showed the reversible and recyclable features of PAA thus confirming its dual role as catalyst stabilizer and reducing agent. This approach provides a significant advantage over conventional methods such as bioremediation which typically require longer time for complete reduction.

Data centers are mission critical facilities that typically contain thousands of data processing equipment, such as servers, switches, and routers. In recent years, there has been a boom in data center usage, leading their energy consumption to grow by about 10% a year continuously. The heat generated in these data centers must be removed so as to prevent high temperatures from degrading their reliability, which would cost additional energy. Therefore, precise and reliable thermal management of the data center environment is critical. This paper focuses on recent advancements in data center modeling and energy optimization. A number of currently available and developmental thermal management technology in data centers are broadly reviewed. Computational fluid dynamics (CFD) for raised-floor data centers, experimental measurements, containment systems, economizer cooling, hybrid cooling, and device level cooling are all thoroughly reviewed. The paper concludes with a summary and presents areas of potential future research, which are based on the holistic integration of workload prediction and allocation, and thermal management using smart control systems.

Entangled carbon nanofibers (CNFs) were synthesized on a flexible carbon fabric (CF) via water-assisted chemical vapor deposition at 800°C at atmospheric pressure utilizing iron (Fe) nanoparticles as catalysts, ethylene (C2H4) as the precursor gas, and argon (Ar) and hydrogen (H2) as the carrier gases. Scanning electron microscopy, transmission electron microscopy, and electron dispersive spectroscopy were employed to characterize the morphology and structure of the CNFs. It has been found that the catalyst (Fe) thickness affected the morphology of the CNFs on the CF, resulting in different capacitive behaviors of the CNF/CF electrodes. Two different Fe thicknesses (5 and 10 nm) were studied. The capacitance behaviors of the CNF/CF electrodes were evaluated by cyclic voltammetry measurements. The highest specific capacitance, approximately 140 F g−1, has been obtained in the electrode grown with the 5-nm thickness of Fe. Samples with both Fe thicknesses showed good cycling performance over 2,000 cycles.