bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential Activation of Signaling Pathways by UVA and UVB Radiation in Normal Human Epidermal Keratinocytes†
Authors: Syed Deeba N. , Afaq Farrukh , Mukhtar Hasan
Published: February 2012

Ultraviolet (UV) radiation from the solar spectrum is a major etiological factor for many cutaneous pathologies including cancer. By understanding changes in cell signaling pathways induced by UVA and UVB, novel strategies for prevention and treatment of UV‐related pathologies could be developed. However, much of the information in the literature from various laboratories cannot cross talk because of difficulties associated with the use of ill‐defined light sources and physiologically irrelevant light dosimetry. Herein, we have assessed the effect of exposure of normal human epidermal keratinocytes (NHEK) to UVA (2 and 4 J cm−2) or UVB (20 and 40 mJ cm−2) radiation. Employing western blot analysis, we found that exposure of NHEK to UVB, but not UVA, phosphorylates JNK1/2 at Th183/Tyr185, STAT3 at Ser727, AKT at Ser473 and increases c‐Fos expression, whereas exposure to UVA, but not UVB, phosphorylates AKT at Thr308. UVB as well as UVA exposure leads to increased phosphorylation of (1) ERK1/2 at Th202/Tyr204; (2) p38 at Th180/Tyr204; (3) STAT3 at Tyr705; (4) mTOR at Thr2448; and (v) p70S6k at Thr421/Ser424; enhanced expression of PI3K (p85) and c‐jun; and nuclear translocation of NFκB proteins. These findings could be considered as a beginning for understanding the differential effects of UVA and UVB in the human skin and may have implications both with respect to risk assessment from exposure to solar UV radiation, and to target interventions against signaling events mediated by UVA and UVB.
Enhanced efficiency of pluvial flood risk estimation in urban areas using spatial–temporal rainfall simulations
Authors: Blanc J. , Hall J.W. , Roche N. , Dawson R.J. , Cesses Y. , Burton A. , Kilsby C.G.
Published: February 2012

Urban areas are concentrations of flood risk because of the density of development and because they tend to be constructed in low‐lying areas. They may be subject to flooding from rivers or the sea but are also vulnerable to the effects of intense direct rainfall, which can overwhelm urban drainage systems, and cause complex and often localised patterns of pluvial flooding. The risk from pluvial flooding is particularly difficult to assess because it is sensitive to the spatial–temporal characteristics of rainfall, local run‐off and surface flow processes, the performance of urban drainage systems, and the exact location of buildings. Sampling the variability or uncertainty in all of these processes in order to generate accurate flood risk estimates quickly becomes computationally prohibitive, especially for large urban areas. In this paper, we evaluate alternative approaches for making use of high‐resolution spatial–temporal rainfall simulations in urban flood risk analysis. Flood depths are computed with a coupled sewer and surface flood model, and flood damage is estimated using standard depth‐damage criteria. Efficient sampling of rainfall events and judicious use of response surfaces that relate rainfall event properties to flood volumes and damages are evaluated and shown to reduce the computational expense of risk analysis by more than 70%. The risk analysis methodology is successfully demonstrated for two contrasting urban locations in the UK.
Little known ophthalmic interests of Emil von Behring, the first Nobel Prize Laureate in Medicine or Physiology
Authors: Grzybowski Andrzej , Wilhelm Helmut
Published: February 2012

Although the work for which Emil von Behring (1854–1917) was awarded the first Nobel Prize Winner for Medicine or Physiology in 1901 was on serum therapy, not only was he trained and worked as an ophthalmologist but he also wrote his doctoral dissertation on a practical ophthalmological topic whilst in Berlin under Carl Schweigger (1830–1905). He later worked for 3 years as an assistant and co‐worker with the famous Polish ophthalmologist Boleslaw Wicherkiewicz (1847–1915), in Poznan where he described an interesting ophthalmic case in a scientific journal. His life and work in other fields have been well studied, but his interests and relationship to ophthalmology that played an important role in, at least part of, Behring’s life have never previously been analysed thoroughly.
The 12th National Lung Cancer Academic Conference in China
Authors: Liu Yi , Chen Gang , Qiu Xiaoming , Chen Jun , Zhou Qinghua
Published: February 2012

Background:  The 12th National Lung Cancer Academic Conference was held in Wu Han, China in 2011.

Methods:  The content of the conference involved recent research achievements and progress in the field of lung cancer, including the epidemiology of lung cancer and molecules, new methods and technology for early‐screening, molecular biology, pharmacogenomics, pathological and medical imaging, “individual therapy” based on molecular markers, surgery, radiation therapy, chemical treatment, and molecular target therapy. The theme of the Conference was “A focus on the quality of life of lung cancer patients in order to optimize individual treatment therapy.”

Results:  Many highly‐respected domestic and foreign lung cancer expert specialists reported the latest achievements of their original clinical multi‐center studies and clinical convert research work, as well as their prospective study results in the field of lung cancer basic and clinical research, including the complete revelation of lung cancer basic research in China, the latest results in clinical transformation, clinical treatment experience, and scientific research achievements.

Conclusion:  The conference substantially influenced China's future basic and clinical research on lung cancer, and contributed to the improvement of diagnostic and therapeutic levels on lung cancer in China.
Nasal Shedding of Equine Herpesvirus‐1 from Horses in an Outbreak of Equine Herpes Myeloencephalopathy in Western Canada
Authors: Burgess B.A. , Tokateloff N. , Manning S. , Lohmann K. , Lunn D.P. , Hussey S.B. , Morley P.S.
Published: February 2012

Background

There is little information on the duration of nasal shedding of EHV‐1 from horses with naturally occurring equine herpesvirus myeloencephalopathy (EHM).

Objectives

To evaluate the duration of nasal shedding of EHV‐1 in horses affected by EHM.

Animals

One hundred and four horses naturally exposed to EHV‐1, 20 of which had clinical signs of EHM.

Methods

All horses on affected premises were monitored. Those horses developing EHM were sampled in a longitudinal outbreak investigation. Nasal swabs were collected daily from 16 of 20 horses affected by EHM. A qPCR was performed on 98 of 246 nasal swab samples to determine nasal shedding duration. Historical and clinical information was analyzed to evaluate potential risk factors for developing EHM and duration of shedding during this outbreak.

Results

The last day shedding was detected in any horse was Disease Day 9. EHV‐1 was detected in two‐thirds of horses tested on Disease Days 0–3. The amount of EHV‐1 DNA found in nasal swabs varied markedly and was not associated with disease severity or age. The odds of developing EHM were greater for febrile horses (OR = 20.3; 95% CI 3.4–390.3; P = .01) as well as for horses attending the riding clinic (OR = 4.1; 95% CI 0.84–21.65; P = .08).

Conclusions and Clinical Importance

Biosecurity measures should be implemented for a minimum of 14 days beyond the onset of clinical signs of EHM. Animal managers cannot rely on the severity of clinical signs to predict the duration of EHV‐1 shedding.
Differences in the morphology of distal border synovial invaginations of the distal sesamoid bone in the horse as evaluated by computed tomography compared with radiography
Authors: Claerhoudt S. , Bergman H. J. , Van Der Veen H. , Duchateau L. , Raes E. V. , SAUNDERS J. H.
Published: February 2012

Reasons for performing study: Distal border synovial invaginations of the distal sesamoid bone are radiographically assessed during the selection process of horses admitted as breeding stallions or in purchase examinations. Nowadays, many moderately or some deeply penetrating proximally enlarged synovial invaginations are considered as moderate or severe radiographic findings.

Objective: To measure the difference between and agreement of the morphology of distal border synovial invaginations on radiography vs. computed tomography (CT). It was hypothesised that the morphology of distal border synovial invaginations would be better evaluable on CT compared with radiography.

Methods: Computed tomography scans and 3 dorsoproximal–palmarodistal oblique (DPr‐PaDiO) radiographs were obtained on 50 cadaver forefeet from 25 Warmblood horses. Computed tomography was assumed to be the gold standard. The number, shape and depth of penetration of distal border synovial invaginations into the distal sesamoid bone were evaluated with both methods, and the comparison of their measurements was statistically described.

Results: A statistically significant mean difference for number of distal synovial invaginations between CT and all 3 DPr‐PaDiO projections was found and was approximately equal to 2, meaning that CT permits visualisation of an average of 2 more invaginations than radiography. In none of the cases did radiography have a higher number observed than CT. A large variation in the difference of measurements for depth of penetration against their mean difference between CT and the 3 radiographic projections was seen. Radiography underestimated the depth of invaginations, and more so when these were deeper. There was no statistically significant mean difference found between the techniques for depth. A moderate to good agreement between measurements on CT and the three DPr‐PaDiO projections for shape was seen, in which the D55°Pr‐PaDiO projection showed the best agreement. A high specificity (90–99%) and low sensitivity (65%) for all projections for shape were found.

Conclusions and potential relevance: Radiography differs considerably from CT concerning the morphology of distal navicular border synovial invaginations. For the evaluation of the number, depth and shape of distal synovial invaginations in the distal sesamoid bone, radiography shows only partially the morphology seen on CT.
Magnetohydrodynamic Transient Free-Convective Flow in a Vertical Annulus With Thermal Boundary Condition of the Second Kind
Authors: Jha Basant K. , Apere Clement A.
Published: February 2012

A theoretical analysis of an unsteady magnetohydrodynamic free-convective flow of a viscous incompressible and electrically conducting fluid between two concentric vertical cylinders is carried out considering thermal boundary condition of the second kind at the outer surface of the inner cylinder. The governing equations of motion and energy are transformed into ordinary differential equations using the Laplace transform technique. The ordinary differential equations are then solved analytically and the Riemann-sum approximation method is used to invert the Laplace domain into time domain. A parametric study depicting the effect of the various parameters on the temperature, velocity, and their related quantities is conducted. On the outer surface of the inner cylinder, the skin friction is seen to decrease with the Hartmann number and increase with time. An opposite behavior is seen on the inner surface of the outer cylinder.
Extended Three-Dimensional Thermo-Hydrodynamic Model of Radial Foil Bearing: Case Studies on Thermal Behaviors and Dynamic Characteristics in Gas Turbine Simulator
Authors: Kim Daejong , Ki Jeongpill , Kim Youngcheol , Ahn Kookyoung
Published: February 2012

Environment-friendly microturbomachinery has its broad current and future applications in fuel cells, power generation, oil-free industrial blowers and compressors, small aero propulsions engines for missiles and small aircrafts, automotive turbo chargers, etc. Air foil bearings (AFBs) have been one of the popular subjects in recent years due to ever-growing interests in the environment-friendly oil-free turbomachinery. AFBs have many noticeable attractive features compared to conventional rigid-walled air/gas bearings such as improved damping and tolerance to minor shaft misalignment and external shocks. In addition, the low viscosity of air or gas allows very low power consumption even at high speeds. A turbine simulator mimicking 50 kW power generation gas turbine was designed. The turbine simulator can generate the same thermodynamic conditions and axial thrust load as the actual gas turbine. In this paper, the 3-D thermo-hydrodynamic (THD) model developed for single radial AFB was further extended to the turbine simulator configuration by extending the solution domain to the surrounding structures including two plenums, bearing sleeve, housing, and rotor exposed to the plenums. In addition, a computational fluid dynamic (CFD) model on the leading edge groove region was developed for better prediction of inlet thermal boundary conditions for the bearing. Several case studies are presented through computer simulations for hydrodynamically preloaded three-pad radial AFB in the hot section. It is found that both bearing and rotor should be provided with cooling air to maintain the temperature of both the rotor and top foil below 300 °C. It is also found that the higher thermal contact resistance between the rotor and hot impellers reduces the axial temperature gradient of the rotor. Dynamic performance of the bearing was evaluated using the linear perturbation method for operation at elevated temperature. The softening effect of the bump foil at elevated temperature results in a decrease of both stiffness and damping coefficients compared to the values at room temperature.
Numerical Model of Microwave Driven Convection in Multilayer Porous Packed Bed Using a Rectangular Waveguide
Authors: Klinbun Waraporn , Rattanadecho Phadungsak
Published: February 2012

The present work studies numerically the heating of multilayer porous packed bed which is subjected to the microwave radiation with a rectangular waveguide. The multilayer porous packed bed consists of the layers of fine and coarse beds. The simulations of electromagnetic field are described by solving Maxwell’s equations with the finite difference time domain (FDTD) method. The flow fields and the temperature profiles are determined by the solutions of the Brinkman–Forchheimer extended Darcy model, energy, and Maxwell’s equations. The study aims to understand of the influences of layered configuration, layered thickness, and operating frequency on the transport processes in a multilayer porous packed bed. The results show that all parameters have significant effect on the distributions of electromagnetic field inside a waveguide, temperature profiles, and velocity fields within the multilayer porous packed bed.
Design, Reliability and Manufacturing Readiness for MEMS Microphone
Authors: Iyer Ganesh , Li Wei , Gopalakrishnan Lavanya
Published: February 2012

Microphone is a critical component for seamless communication converting an acoustic signal (vocal) to an electrical signal. Traditionally Electrets Condenser Microphones (ECM) have been the primary proponent of audio component in many consumer products. With functionally rich consumer devices (example smart phones, etc) there is a growing trend to look at components with higher functionality but a smaller form factor. Microelectronic Mechanical Systems (MEMS) microphone is seen as a possible replacement to ECM due to its significant reduction in form fit with additional functionality. The paper is an effort to illustrate steps that can be considered while designing MEMS microphone in a system. This includes Design considerations, Reliability tests, Manufacturing challenges and Readiness to ensure higher yield during the final assembly. Manufacturing issues (Top 5) and guideline presented in the paper are not just to increase the assembly yield (system level), but also to increase an awareness upfront to the design phase to help create a robust system/product.
Hybrid Cooling Technology for Large-Scale Computing Systems: From Back to the Future
Authors: Wei Jie
Published: February 2012

A technical perspective of hybrid cooling methodology, comprised of pumped water cooling with incorporated convection air cooling, for densely packaged high performance computing systems is presented in this paper. The technology has been implemented in the Fujitsu high-end server GS8900 (released in 1999), and proposed with technical innovations for future large-scale computing systems. Design strategies of cooling systems, including water cooling modules, water flow and distribution units as well as air convection architectures, are reviewed, together with advantages and performance of the technology analyzed. Low temperature chilled water is utilized in these systems, where the system board is assembled with a liquid cooling unit on each one for cooling of major processor and supporting chips. Memory modules, other devices and components on the system board, as well as power supply units in the rack, are cooled by ambient air convection. Besides of the high cooling capability, attention is given especially to advantages of the technology with tremendously lowered power consumption, enhanced system reliability and increased packaging density, improvements in cooling efficiency and easy of serviceability are emphasized as well.
Numerical Simulation of Local Heat Transfer and Scaling of a Synthetic Impinging Jet in a Canonical Geometry
Authors: Silva Luis , Ortega Alfonso
Published: February 2012

Synthetic jets are generated by an equivalent inflow and outflow of fluid into a system. Even though such a jet creates no net mass flux, net positive momentum can be produced because the outflow momentum during the first half of the cycle is contained primarily in a vigorous vortex pair created at the orifice edges whereas in the backstroke, the backflow momentum is weaker, despite the fact that mass is conserved. As a consequence of this, the approach can be potentially utilized for the impingement of a cooling fluid over a heated surface. In the present study, a canonical geometry is presented, in order to study the flow and heat transfer of a purely oscillatory jet that is not influenced by the manner in which it is produced. The unsteady Navier-Stokes equations and the convection-diffusion equation were solved using a fully unsteady, two-dimensional finite volume approach in order to capture the complex time dependent flow field. A detailed analysis was performed on the correlation between the complex velocity field and the observed wall heat transfer. A fundamental frequency, in addition to the jet forcing frequency, was found, and was attributed to the coalescence of consecutive vortex pairs. In some instances, this vortex pairing can lead to zones of low heat transfer. Two point correlations showed that the Nusselt number Nu, showed stronger correlation with the vertical velocity v although the spatial-temporal dependencies are not yet fully understood. It was found that the Reynolds number and the Strouhal number, are sufficient to successfully scale the problem at larger dimensions and this is presently being exploited in order to design validation experiments using jets large enough to allow careful local measurements.
Multiphysics Approach to Modeling Supercapacitors for Improving Performance
Authors: Xu Xinqiang , Sammakia Bahgat G. , Jung DaeYoung , Eilertsen Thor
Published: February 2012

Supercapacitors are a strong candidate for high-power applications such as electric/hybrid vehicles and electronic devices due to their high power densities and high efficiency particularly at low temperatures. In these applications, supercapacitors are used as energy-storage devices with capability of providing the peak-power requirement. They are subject to heavy duty cycling conditions which result in significant heat generation inside the supercapacitors. Therefore, thermal management is a key issue concerning lifetime and performance of supercapacitors. Accurate modeling of temperature field inside supercapacitors is essential for designing an appropriate cooling system, meeting the safety and reliability requirements of power systems. The objective of this paper is to study the transient and spatial temperature distribution in supercapacitors, in which a supercapacitor product with prismatic structure, based on the activated carbon and organic electrolyte technology, was chosen for modeling. A multi-dimensional thermal and electrochemical coupled model was developed by a commercial software COMSOL. In this approach, the 3D energy equation was coupled with a 1D electrochemical model via the heat generation and temperature-dependent physicochemical properties, including diffusion coefficient and ionic conductivity of electrolyte ions. Location-dependent convection and radiation boundary conditions were applied to reflect different heat dissipation phenomena of all surfaces. This model is capable of predicting electrochemical performance and temperature distribution for different involved parameters. The results of this model can also be used to determine the optimum thermal management system for various supercapacitor applications.
Evaluation of the Reliability of Film Adhesives Under Hygrothermal Condition
Authors: Saiki Naoya , Inaba Kazuaki , Kishimoto Kikuo , Senoo Hideo
Published: February 2012

Mechanical evaluation method of adhesive strength for bonding IC chips in chip-stacked packages is investigated. These film adhesives are required to bond IC chips securely under JEDEC moisture/reflow test. The stress condition of film adhesives under the moisture/reflow test is analyzed by FEM to clarify proper stress condition for the adhesive test. Thermal strain, moisture expansion and strain induced by vapor pressure is considered. It is found that the shear stress is the main loading factor on reflow process in the analysis. A shear test using chevron-shaped chip is proposed as the adhesive test, which apply shear load to the film adhesive at the corner of a chip. The specimen is fabricated by the same process of actual semiconductor manufacturing. The evaluation method is conducted without any problem. The proposed method is thought to be suitable for film adhesives of chip bonding.
Fundamental Study on Thermal Characteristics of Heat Spreaders
Authors: Koito Yasushi , Nonaka Yusaku , Tomimura Toshio
Published: February 2012

A heat spreader is one of the solutions for thermal management of electronic and photonic systems. By placing the heat spreader between a small heat source and a large heat sink, the heat flux is spread from the former to the latter, resulting in a lower thermal spreading resistance between them. There are many types of heat spreaders known today having different heat transfer modes, shapes and sizes. This paper describes the theoretical study to present the fundamental data for the rational use and thermal design of heat spreaders. Two-dimensional disk-shaped mathematical model of the heat spreader is constructed, and the dimensionless numerical analysis is performed to investigate the thermal spreading characteristics of the heat spreaders. From the numerical results, the temperature distribution and the heat flow inside the heat spreaders are visualized, and then the effects of design parameters are clarified. The discussion is also made on the discharge characteristics of the heat spreaders. Moreover, a simple equation is proposed to evaluate the heat spreaders.
Characterization of Metallically Bonded Carbon Nanotube-Based Thermal Interface Materials Using a High Accuracy 1D Steady-State Technique
Authors: Wasniewski Joseph R. , Altman David H. , Hodson Stephen L. , Fisher Timothy S. , Bulusu Anuradha , Graham Samuel , Cola Baratunde A.
Published: February 2012

The next generation of Thermal Interface Materials (TIMs) are currently being developed to meet the increasing demands of high-powered semiconductor devices. In particular, a variety of nanostructured materials, such as carbon nanotubes (CNTs), are interesting due to their ability to provide low resistance heat transport from device to spreader and compliance between materials with dissimilar coefficients of thermal expansion (CTEs). As a result, nano-Thermal Interface Materials (nTIMs) have been conceived and studied in recent years, but few application-ready configurations have been produced and tested. Over the past year, we have undertaken major efforts to develop functional nTIMs based on short, vertically-aligned CNTs grown on both sides of a thin interposer foil and interfaced with substrate materials via metallic bonding. A high-precision 1-D steady-state test facility has been utilized to measure the performance of nTIM samples, and more importantly, to correlate performance to the controllable parameters. Nearly 200 samples have been tested utilizing myriad permutations of such parameters, contributing to a deeper understanding and optimization of CNT growth characteristics and application processing conditions. In addition, we have catalogued thermal resistance results from a variety of commercially-available, high-performance thermal pads and greases. In this paper, we describe our material structures and the parameters that have been investigated in their design. We report these nTIM thermal performance results, which include a best to-date thermal interface resistance measurement of 3.5 mm2-K/W, independent of applied pressure. This value is significantly better than all commercial materials we tested and compares favorably with the best results reported for CNT-based nTIMs in an application-representative setting.
Design, Optimization and Thermal Analysis of Motor-Controllers in a Quadruped Robot
Authors: Kannan Naveen , Shah Niket , Agonafer Dereje , Bowling Alan
Published: February 2012

Robot is an electromechanical device or machine which is controlled by computer or electronic programming to perform tasks automatically. Mobile robots in particular have become very popular and are used for numerous applications such as industries, military, factories and for performing many dangerous and inaccessible tasks. Robots generally vary in size from extremely small to large scales. Robot is a costly device and involves complex components / functionalities there by leading to immense heat dissipation. Thermal management of the robot holds the key which contains motor controllers that generate a tremendous amount of heat as it will affect its agility and mechanical reliability. This paper involves the design & cooling techniques of a quadruped robot.
Enhanced Thermal Map Prediction and Floor Plan Optimization in Electronic Devices Considering Sub-Continuum Thermal Effects
Authors: Romero David , Nabovati Aydin , Refai-Ahmed Gamal , Sellan Daniel P. , Ghalambor Saeed , Shah Niket , Agonafer Dereje , Amon Cristina H.
Published: February 2012

In current and next-generation semiconductor electronic devices, sub-continuum heat transfer effects and non-uniform power distribution across the die surface lead to large temperature gradients and localized hot spots on the die. These hot spots can adversely affect device performance and reliability. In this work, we propose an enhanced method for thermal map prediction that considers sub-continuum thermal transport effects and show their impact in floor plan optimization. Sub-continuum effects are expressed in terms of an effective thermal conductivity. We introduce and calibrate a 2D thermal model of the die for fast simulation of thermal effects under non-uniform power generation scenarios. The calibrated 2D model is then used to study the impact of the effective thermal conductivity on the thermal map prediction and floor plan optimization. Results show that sub-continuum effects radically change both the predicted thermal performance and the optimal floor plan configurations.
Multivariate Prediction of Airflow and Temperature Distributions Using Artificial Neural Networks
Authors: Song Zhihang , Murray Bruce T. , Sammakia Bahgat
Published: February 2012

Thermal Management optimization for data centers, including prediction of airflow and temperature distributions, is generally an extremely time-consuming process using full-scale CFD analysis. Reduced order models are necessary in order to provide real-time assessment of cooling requirements for data centers. The use of a simulation-based Artificial Neural Network (ANN) is being investigated as a predictive tool. A model for a basic hot aisle/cold aisle data center configuration was built and analyzed using the commercial software FloTHERM. The flow field and temperature distributions were obtained for 100 representative sets of operating conditions using the CFD package. The Latin Hypercube Sampling technique was employed to select values for three design variables: plenum height, percentage open area of the perforated tiles and air leakage fraction. The FloTHERM results were used to generate a database for the ANN training. The CFD results from 85 cases were used for training and 16 cases were used for validation. A multivariate mapping between the input design variables and output variables (individual tile flow rates and maximum rack temperatures) was obtained. Good agreement (0.5% average relative error) was obtained between the ANN model predictions and the CFD results. These preliminary results are promising and show that an ANN based model may yield an effective real-time thermal management design tool for data centers.
Material Optimization for Concentrated Solar Photovoltaic and Thermal Co-Generation
Authors: Yazawa Kazuaki , Shakouri Ali
Published: February 2012

We conducted an analytic study of concentrated solar photovoltaic and hot water co-generation based on various solar cell technologies and micro channel heat sinks. By co-optimizing the electricity generation and heat transport in the system, one can minimize the cost of the key materials and compare different tradeoffs as a function of concentration ratio or other parameters. Concentrated solar Photovoltaic (PV) based on multi junction cells can yield around 35–40% efficiency. They are suitable for high photon energy flux and they are already available in the market. However, due to high heat fluxes at large concentrations, such as 100–1000 Suns, heat sinks could be costly in terms of material mass, space, energy for pumping fluid, and system complexity. In addition, since the efficiency of solar cells decreases as the ambient temperature increases, there is a tradeoff between electricity and hot water cogeneration. Similar to our previous analysis of thermoelectric (TE) and hot water co-generation, PV/solar thermal system is also optimized. The results are compared with thermoelectric systems as a function of the concentration ratio. The solar concentrated co-generation system using either PV or TE for direct electricity generation collects more than 80% of solar energy when it is optimized. We calculate the overall cost minima as a function of concentration ratio. Although there are some differences between PV and TE, the optimum concentration ratio for the system is in the range of 100–300 Suns for both.
Design for Reliability of Stacked Die Package Using TSV Technology
Authors: Thakur Shiwani , Nakanekar Satej , Kaisare Abhijit , Tonapi Sandeep
Published: February 2012

A thermo-mechanical analysis is carried out on a stacked die package having through silicon via technology to study the overall reliability of the package due to varying aspect ratio (size and shape) of through silicon vias, silicon die thickness, underfill thickness and underfill material properties. Through silicon via technology is one of the most rapidly developing technologies in the semiconductor industry and assures the development for the continued role of Moore’s law and multichip integration as well as packaging approaches. Wire bond and flip-chip have been in use for long time now while TSV is the latest technology of 3D integration system which is used for primary interconnection. The benefits of the use of TSV technology are increased performance, reduced form factor and cost reduction of the package. A three dimensional finite element model of a stacked package that consists of stacked dice using through silicon vias, solder interconnect, underfill, substrate and PWB is solved numerically to assess the reliability of the overall stacked package. In this analysis, stress free temperature for stacked package is kept at 125°C while room temperature is 25°C to carry out the simulation of the stresses post cure cool down of the stacked package. Stresses are calculated at the die as well as interfaces between underfill and die and underfill and substrate to assess the reliability of the overall package. A parametric study of critical geometric parameters such as aspect ratio, thickness of silicon die and underfill thickness and process parameters is carried out to minimize the maximum stresses on the overall stacked package. Recommendations are provided with respect to controlling the critical parameters such as aspect ratio, silicon thickness, underfill thickness and varying the underfill material properties (E and α) to improve the overall reliability and strength of the package.
Signal and Power Integrity Co-Simulation on DDR Memory
Authors: Quddus Md. Ruhul , Soman Sanjiv
Published: February 2012

Even though it has always been known that Signal Integrity analysis and Power Integrity (Power Delivery) analysis are related, historically they have been treated and analyzed independently with some timing and voltage buckets used to tie the effects of one on the other. When the voltage and timing margins were large, this approach worked quite well. However as voltage levels, timing windows and their margins have shrunk, the traditional method of analyzing them independently no longer suffices. The signal quality and timing (eye height & eye width) losses due to the effects of power delivery are no longer negligible. The concept of signal integrity & power delivery co-simulation (referred to as SIPD or SIPI co-sim) is a methodology developed to address this problem. In this paper we will use the DDR bus as an example to illustrate the impacts of power delivery on the signal and highlight how badly the margin loss would have been underestimated if the effects of power delivery were ignored. The paper will demonstrate how SIPD co-sim can quantify or illustrate - the effects of data randomization, margin gain with fully random data patterns, margin loss due to the effects of Burst-Idle-Burst data patterns, definition of noise & eye diagram BER, statistically significant noise in system, etc.
Power/Ground Pin-Map Design for Power Integrity
Authors: Kim Jingook , Drewniak James , Fan Jun
Published: February 2012

In this paper, a simple circuit model for IC multiple power and ground via arrays in a multilayer PCB is built based on the resonant cavity model. Using the circuit model, the parasitic inductance for the IC power and ground connection is quantitatively investigated according to via number and via patterns. The stack-up configuration of the power/ground plane pair is not critical for PDN performance in multilayer PCBs, as long as there are sufficient IC power/ground vias in an alternating pattern. The outcome of this work can be used to guide the pin-map design for high-speed packages.
Scalable Microsprings for Integrated Test and Packaging
Authors: Chow Eugene M.
Published: February 2012

Lithographically defined spring electrical contacts have many applications for next generation electronics test and packaging. The springs can lower the cost of multi-chip modules because their rework ability addresses the known-good-die problem. Lower height chip stacking for mobile electronics markets is enabled because a sliding spring can have a much shorter profile than solder. Larger die can be directly bonded to the board because the compliance absorbs thermal expansion mismatches between substrates. Significant stress isolation is possible, which is important for mechanically sensitive die such as MEMS and low K die. Very high density is possible, as 6 (am pitch has been demonstrated. Fabrication is scalable and assembly is low temperature. This paper reviews our prototype demonstrations for these applications as well as relevant reliability data and contact studies.
Influence of temperature ramp on the materials properties of GaSb grown on ZnTe using molecular beam epitaxy
Authors: Fan Jin , Ouyang Lu , Liu Xinyu , Ding Ding , Furdyna Jacek K. , Smith David J. , Zhang Yong-Hang
Published: February 2012

This paper reports high-quality GaSb grown on ZnTe using molecular beam epitaxy with a temperature ramp during growth, and investigates the influence of the temperature ramp on material properties. During growth, in situ reflection-high-energy electron diffraction shows rapid and smooth transition from ZnTe surface reconstruction to GaSb surface reconstruction. Post-growth structural characterization using x-ray diffraction and transmission electron microscopy reveals smooth interface morphology and low defect density. Strong photoluminescence emission is observed up to 200 K. The sample grown with a temperature ramp from 360 to 470 °C at a rate of 33 °C/min showed the narrowest bound exciton emission peak with a full width at half maximum of 15 meV.
Bottom parameter behavior in shallow water
Authors: Tolstoy A.
Published: February 2012

This paper discusses the matched field processing behavior of key geoacoustic parameters as a function of frequency (25–100 Hz), range (250 m–2 km), and sediment layer thickness (12, 22, 40 m with scenarios corresponding to possible Shallow Water’06 tests) in a systematic manner for simulated data. It considers ideal, as well as approximate knowledge of other conditions, such as source depth, phone depth, and an ocean sound-speed profile. Some of these approximations cause more trouble than others, but they are all still manageable at the low frequencies and short ranges of interest here. A single layer sediment is always assumed here, as is a vertical array and range independence. However, the approach is easily adaptable to other situations. Finally, we introduce a new way of processing broadband information and find that averaging over all available frequencies and ranges may not be optimal for maximizing sensitivity to, e.g., finding, geoacoustic parameters.
Statistics of low-frequency normal-mode amplitudes in an ocean with random sound-speed perturbations: Shallow-water environments
Authors: Colosi John A. , Duda Timothy F. , Morozov Andrey K.
Published: February 2012

Second- and fourth-moment mode-amplitude statistics for low-frequency ocean sound propagation through random sound-speed perturbations in a shallow-water environment are investigated using Monte Carlo simulations and a transport theory for the cross-mode coherence matrix. The acoustic observables of mean and mean square intensity are presented and the importance of adiabatic effects and cross-mode coherence decay are emphasized. Using frequencies of 200 and 400 Hz, transport theory is compared with Monte Carlo simulations in a canonical shallow-water environment representative of the summer Mid-Atlantic Bight. Except for ranges less than a horizontal coherence length of the sound structure, the intensity moments from the two calculations are in good agreement. Corrections for the short range behavior are presented. For these frequencies the computed mode coupling rates are extremely small, and the propagation is strongly adiabatic with a rapid decay of cross-mode coherence. Coupling effects are predicted to be important at kilohertz frequencies. Decay of cross-mode coherence has important implications for acoustic interactions with nonlinear internal waves: For the case in which the acoustic path is not at glancing incidence with a nonlinear internal-wave front, adiabatic phase randomizing effects lead to a significantly reduced influence of the nonlinear waves on both mean and mean square intensity.
Sequential geoacoustic inversion at the continental shelfbreak
Authors: Yardim Caglar , Gerstoft Peter , Hodgkiss William S.
Published: February 2012

Environmental parameters can have large spatial and temporal variability in shelfbreak regions. The capability of sequential Bayesian filters in tracking this variation is investigated. Particle filtering (PF) is used to extract the environmental parameters and their uncertainties. The method tracks the environment with fewer particles relative to conventional geoacoustic inversion methods using successive independent inversions. As an example, data from the Shallow Water 2006 Experiment are processed. The PF approach first is used to track the source and the environment with little spatial variation just northwest of the shelfbreak. Then the strongly range-dependent shelfbreak region is analyzed and the PF results are compared to previous geoacoustic inversion studies from the region.
Low-frequency broadband sound source localization using an adaptive normal mode back-propagation approach in a shallow-water ocean
Authors: Lin Ying-Tsong , Newhall Arthur E. , Lynch James F.
Published: February 2012

A variety of localization methods with normal mode theory have been established for localizing low frequency (below a few hundred Hz), broadband signals in a shallow water environment. Gauss-Markov inverse theory is employed in this paper to derive an adaptive normal mode back-propagation approach. Joining with the maximum a posteriori mode filter, this approach is capable of separating signals from noisy data so that the back-propagation will not have significant influence from the noise. Numerical simulations are presented to demonstrate the robustness and accuracy of the approach, along with comparisons to other methods. Applications to real data collected at the edge of the continental shelf off New Jersey, USA are presented, and the effects of water column fluctuations caused by nonlinear internal waves and shelfbreak front variability are discussed.
On whether azimuthal isotropy and alongshelf translational invariance are present in low-frequency acoustic propagation along the New Jersey shelfbreak
Authors: Lynch James F. , Emerson Chris , Abbot Philip A. , Gawarkiewicz Glen G. , Newhall Arthur E. , Lin Ying-Tsong , Duda Timothy F.
Published: February 2012

To understand the issues associated with the presence (or lack) of azimuthal isotropy and horizontal (along isobath) invariance of low-frequency (center frequencies of 600 Hz and 900 Hz) acoustic propagation in a shelfbreak environment, a series of experiments were conducted under the Autonomous Wide-Aperture Cluster for Surveillance component of the Shallow Water 2006 experiment. Transmission loss data reported here were from two mobile acoustic sources executing (nearly) circular tracks transmitting to sonobuoy receivers in the circle centers, and from one 12.5 km alongshelf acoustic track. The circle radii were 7.5 km. Data are from September 8, 2006. Details of the acoustic and environmental measurements are presented. Simple analytic and computer models are used to assess the variability expected due to the ocean and seabed conditions encountered. A comparison of model results and data is made, which shows preliminary consistency between the data and the models, but also points towards further work that should be undertaken specifically in enlarging the range and frequency parameter space, and in looking at integrated transmission loss.
Comparison of hybrid three-dimensional modeling with measurements on the continental shelf
Authors: Heaney Kevin D. , Campbell Richard L. , Murray James J.
Published: February 2012

During the CALOPS 2007 experiment, off the coast of Fort Lauderdale, Florida, three-dimensional (3D) multipath was observed using a bottom mounted horizontal line array during source tows along the 200 m isobath [Kevin D. Heaney and James J. Murray, J. Acoust. Soc. Am. 125(4), 1394–1402 (2008)]. In this paper a hybrid modeling approach is presented to model the 3D sound on the Florida shelf, nearly shaped like the canonical wedge. The hybrid approach combines vertical acoustic normal modes with the parabolic equation solution (in range/cross-range). The approach is shown to satisfy the 3D Cartesian-coordinate wave equation in the limit of adiabatic mode propagation. In the adiabatic mode parabolic equation (AMPE) approach modal phase speeds vs position are used as the input to the parabolic equation computation with dimensions of easting (km) and northing (km). Vertical adiabatic modes and horizontal rays are also computed to illustrate the 3D multipath arrival. The AMPE field is computed for all the modes for each element of the horizontal array. Beamforming vs source range is then conducted and excellent agreement with data is achieved.
Reliability of distortion-product otoacoustic emissions and their relation to loudness
Authors: Thorson Megan J. , Kopun Judy G. , Neely Stephen T. , Tan Hongyang , Gorga Michael P.
Published: February 2012

The reliability of distortion-product otoacoustic emission (DPOAE) measurements and their relation to loudness measurements was examined in 16 normal-hearing subjects and 58 subjects with hearing loss. The level of the distortion product (Ld) was compared across two sessions and resulted in correlations that exceeded 0.90. The reliability of DPOAEs was less when parameters from nonlinear fits to the input/output (I/O) functions were compared across visits. Next, the relationship between DPOAE I/O parameters and the slope of the low-level portion of the categorical loudness scaling (CLS) function (soft slope) was assessed. Correlations of 0.65, 0.74, and 0.81 at 1, 2, and 4 kHz were observed between CLS soft slope and combined DPOAE parameters. Behavioral threshold had correlations of 0.82, 0.83, and 0.88 at 1, 2, and 4 kHz with CLS soft slope. Combining DPOAEs and behavioral threshold provided little additional information. Lastly, a multivariate approach utilizing the entire DPOAE I/O function was used to predict the CLS rating for each input level (dB SPL). Standard error of the estimate when using this method ranged from 2.4 to 3.0 categorical units (CU), suggesting that DPOAE I/O functions can predict CLS measures within the CU step size used in this study (5).
Fast implementation of sparse iterative covariance-based estimation for source localization
Authors: Zhang Qilin , Abeida Habti , Xue Ming , Rowe William , Li Jian
Published: February 2012

Fast implementations of the sparse iterative covariance-based estimation (SPICE) algorithm are presented for source localization with a uniform linear array (ULA). SPICE is a robust, user parameter-free, high-resolution, iterative, and globally convergent estimation algorithm for array processing. SPICE offers superior resolution and lower sidelobe levels for source localization compared to the conventional delay-and-sum beamforming method; however, a traditional SPICE implementation has a higher computational complexity (which is exacerbated in higher dimensional data). It is shown that the computational complexity of the SPICE algorithm can be mitigated by exploiting the Toeplitz structure of the array output covariance matrix using Gohberg–Semencul factorization. The SPICE algorithm is also extended to the acoustic vector-sensor ULA scenario with a specific nonuniform white noise assumption, and the fast implementation is developed based on the block Toeplitz properties of the array output covariance matrix. Finally, numerical simulations illustrate the computational gains of the proposed methods.