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In this study, cooling methods for a typical spacecraft circuit board assembly are investigated. The power dissipation of the assembly is more than 100 W, and the max heat dissipation of a component is 16 W, making it very difficult to cool the assembly. According to the packaging characteristics and heat dissipation of the components on the circuit board, cooling methods such as potting brackets, cooling springs, and cooling blocks are used, and the effects of various cooling methods are analyzed. Through simulation and experimental research, it is proven that the power components in the printed circuit board assembly meet the requirements of temperature derating, which provides a reference for the thermal design of spacecraft electronic equipment. [ABSTRACT FROM AUTHOR]

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In this paper, an improved voltage-mode constant on-time (COT) control DC–DC buck converter is designed, which makes the DC–DC buck converter have good stability. Firstly, an improved compensation scheme is introduced through the analysis and derivation of the traditional voltage-mode COT controlled buck converter model. Then, according to the application requirements of the design, Simplis software modeling is used to verify the correctness of the theoretical analysis. The 0.13 μ m BCD technology is used to tape out the DC–DC converter of the improved voltage mode COT. The input voltage is 3.7–5.5 V and the output voltage is 3.3 V. The chip test mainly includes heavy-load condition in CCM operation, light-load condition in DCM operation, and load transient response. The test results show that the chip can remain stable under heavy-load and light-load conditions. The overshoot and undershoot in transient response can be quickly restored to steady state during the recovery process. Finally, compared with chips of the same type, it shows that the DC–DC chip for portable electronic equipment designed in this paper adopts an internal compensation structure, which has good stability, simple design, small main chip area, simple peripheral equipment, and good application value. [ABSTRACT FROM AUTHOR]

As forced-air cooling for heat sinks is widely used in the cooling design of electrical and electronic equipment, their thermal performance is of critical importance for maintaining excellent cooling capacity while reducing the size and weight of the heat sink and the equipment as a whole. This paper presents a method based on the combination of computational fluid dynamics (CFD) simulation and surrogate models to optimize heat sinks for high-end energy storage converters. The design takes the thermal resistance and mass of the heat sink as the optimization goals and looks for the best design for the fin height, thickness and spacing, as well as the base thickness. The analytical and numerical results show that the thermal resistance and mass of the heat sink are reduced by the proposed algorithms, as are the temperatures of the heating elements. Test results verify the effectiveness of the optimization method combining CFD simulation with surrogate models. [ABSTRACT FROM AUTHOR]

In order to ensure the normal operation of software electronic equipment and better guide the electromagnetic protection design of software electronic equipment, a set of computational models and numerical methods are needed to analyze the electromagnetic interference problems of electronic equipment. To this end, a new field-path hybrid time domain algorithm is adopted to simulate the electromagnetic interference of broadband electromagnetic signals to software electronic equipment in the time domain; the results are compared with those of the FDTD method to verify the correctness and efficiency of the algorithm. The average calculation time of FDTD is 478.3 min, while that of the field-path hybrid time domain algorithm is 46.5 min. The results show that the simulation effect of the field-path hybrid time domain algorithm is consistent with that of FDTD and saves a lot of memory and computation time, which proves the correctness and efficiency of the algorithm. [ABSTRACT FROM AUTHOR]

A radar system requires a number of high-power components operating in a narrow and convection-free environment. This study aims to develop an integrated heat dissipation system that is suitable for the high-power electronic equipment of radar systems. The proposed heat dissipation mechanism integrates a fluid circulation-type cold plate with a quad transmit receive module. The finite element method in the COMSOL fluid–solid coupling heat transfer analysis software was used to analyze the heat dissipation performance of the cold plate in the proposed mechanism. The Taguchi method was adopted to optimize the cold plate design. The simulation and experimental results show that the proposed mechanism can control the temperature equalization and temperature of the system within the specified requirements. The practicality of the proposed mechanism was verified. The findings can serve as a reference for the design of high-power electronic equipment in a heat dissipation system. [ABSTRACT FROM AUTHOR]

In electronic equipment, thermal failure and thermal degradation are two increasingly prominent problems of the devices, with the deepening integration and growing power density. Currently, there are relatively few reports on the heat transfer mechanism, heat source analysis, and numerical simulation of electronic equipment containing power electronic devices (PEDs). Therefore, this paper carries out thermal design and evaluates the cooling performance of PED-containing electronic equipment. Firstly, the basic flow was given for the thermal design of PED-containing electronic equipment; the heat transfer mode of PEDs and the equipment were detailed, so was the principle of thermal design; the cooling principles were introduced for ventilation cooling, heat pipe cooling, and closed loop cooling. Then, numerical simulation was carried out on the solid and liquid state heat transfer of PEDs and the equipment under different cooling modes. Based on an engineering example, the cooling scheme was finalized through heat source analysis on the proposed electronic equipment. The experimental results rove the effectiveness of numerical simulation and electronic equipment cooling scheme. The results provide a reference for the cooling scheme design for other fields of thermal design. [ABSTRACT FROM AUTHOR]

Here, the setup of a three-phase 100 A linear amplifier is proposed. This work focusses on the use of this linear amplifier as power element for machine-emulation. In contrast to common power electronics, a linear amplifier avoids ripple content in the output current caused by switched-mode operation. [ABSTRACT FROM AUTHOR]

Heat sinks (HSs) are designed for the mechanical, electrical and electronic components that generate heat in considerable amount. For this purpose, an aluminum conical pin fin heat sink is designed. Aluminum conical pin-fins geometry has been experimentally investigated for the blowing direction (pushing or pulling) which is the energy efficient option for the heat sink. The heat sink was tested at the same fan power for pushing and pulling conditions for 25, 50, 75 and 100 W resistance heater power. Designed aluminum conical pin fin heat sink can be easily used in heat sweeping processes. It has found that pushing configuration of the fan is more efficient for this design. [ABSTRACT FROM AUTHOR]

This work describes the use of a benchtop razor printer to fabricate epidermal paper-based electronic devices (EPEDs). This fabrication technique is simple, low-cost, and compatible with scalable manufacturing processes. EPEDs are fabricated using paper substrates rendered omniphobic by their cost-effective silanization with fluoroalkyl trichlorosilanes, making them inexpensive, water-resistant, and mechanically compliant with human skin. The highly conductive inks or thin films attached to one of the sides of the omniphobic paper makes EPEDs compatible with wearable applications involving wireless power transfer. The omniphobic cellulose fibers of the EPED provide a moisture-independent mechanical reinforcement to the conductive layer. EPEDs accurately monitor physiological signals such as ECG (electrocardiogram), EMG (electromyogram), and EOG (electro-oculogram) even in high moisture environments. Additionally, EPEDs can be used for the fast mapping of temperature over the skin and to apply localized thermotherapy. Our results demonstrate the merits of EPEDs as a low-cost platform for personalized medicine applications. [ABSTRACT FROM AUTHOR]

Mode conversion in differential lines paired with serpentine in PCB layouts of mobile electronic devices is investigated. Different shapes and dimensions are analyzed and design of experiments based on Response Surface Model is used to study the sensitivity of various design parameters to both signal integrity and electromagnetic interference. It is found that mode conversion is negatively affected by the numbers of meanders, the length of bends and their angle. Design guidelines are provided and an alternative shape named trombone is proposed as possible solution to minimize the mode conversion while maximizing the skew matching and reducing the routing area. More than 10 dB of reduction in common mode noise is achieved in a broadband frequency range 0–10 GHz for most of the cases studied. [ABSTRACT FROM PUBLISHER]

This paper describes a method for developing a novel, low-cost, hand-held electronic nose (E-Nose) for black tea flavor estimation using metal–oxide–semiconductor gas sensors. In this research, a first-level experimentation has been conducted with a computer-assisted-technology-based system for sensor selection and validation. In the second level, a novel hand-held E-Nose is designed and developed for generation of tea aroma, capturing the response patterns and signal processing in a microcontroller (PIC 18F45K22) for tea flavor grading. The results of the first-level experimentation provide the sensor selection, where only four out of 12 sensors were selected based on their performance. Moreover, the classification network was predetermined for implementation in the microcontroller. Experiments conducted on the developed hand-held E-Nose show the classification on eight different grades of tea (each with ten samples) varying from 70% to 100%, revealing an average classification efficiency of 90%. The repeatability of the system was also found to be 80%. The developed system also overcomes the problem of heating the tea sample, since the volatile organic compounds of tea are generated due to the emitted heat of the sensors in the proposed system. [ABSTRACT FROM PUBLISHER]

The paper presents the first tool for the emulation of microelectromechanical systems (MEMSs) to be used for the characterization of electronics designed for MEMS. With such a tool, electronics of different nature (integrated, discrete-component, and instrumentation) can be tested (debugged) as in operation, even in the absence of physically available MEMS transducers. The proposed MEMS emulator (MEMU) was implemented through a field-programmable gate array (FPGA) core that synthesized the MEMS transfer function, and through interfaces to the analog electronics under test (ADC to sense signals generated by the electronics, and DAC to provide the emulated MEMS output signal). The parallelism and programmability offered by the FPGA implementation allowed to synthesize several second-order effects of MEMS (noise, spurious modes, feedthrough capacitance, and so on) and to cover a wide range of selectable MEMS parameters. A first prototype of MEMU was developed and experimented. Various MEMS operating up to 25 kHz, with quality factors in the 10−1–10−6 range, were successfully emulated with associated non-idealities. Furthermore, the test of a printed circuit electronic board for piezoresistive MEMS resonators coupled to MEMU to realize a MEMU-based oscillator was shown as a paradigmatic example of the debugging of electronics for MEMS transducers. [2017-0219] [ABSTRACT FROM PUBLISHER]

With the rapid arising of information technology, microwave absorbing materials (MAMs) are playing an increasingly significant role in electronic reliability, healthcare, and national defense security. Hence, development of high performance MAMs with thin thickness, low density, wide bandwidth, and strong absorption has attracted great interests. Recently, taking graphene as MAMs for high-performance electromagnetic (EM) wave attenuation has grabbed considerable attention, owing to their low density, high specific surface area, strong dielectric loss, and high electronic conductivity. Furthermore, in order to address the interfacial impedance mismatching of the sole graphene materials, incorporation of other lossy materials has been widely studied as the imperative solution to improve its MA performance. In this review, we introduce the theory of microwave absorption and summarize recent advances in the fabrication of graphene-based MAMs, including rational design of the microstructure of pure graphene and tunable chemical integrations with polymers, magnetic metals, ferrites, ceramics, and multicomponents composites. The key point of enhancing MA in graphene-based MAMs is to regulate their EM properties, improve of impedance matching, and create diversified loss mechanisms. Furthermore, the shortcomings, challenges, and prospects of graphene-based MAMs are also put forward, which will be helpful to people working in the related fields. [ABSTRACT FROM AUTHOR]

A mobile manipulator is a robotic system consisting of a mobile platform on which a manipulator arm is mounted, allowing the robotic system to perform locomotion and manipulation tasks simultaneously. A mobile manipulator has several advantages over a robot manipulator which is fixed, the main advantage is a larger workspace. The robots manipulators are oriented to work collaboratively with the human being in tasks that simultaneously require mobility and ability to interact with the environment through the manipulation of objects. This article will present the electronic design for a mobile robot manipulator with five degrees of freedom and a 6-wheel traction with four of these directional. [ABSTRACT FROM AUTHOR]

Mobile devices are widely used nowadays boosted by the fast development of technology. Most mobile device embedded touch screen user interface which come in various sizes. This study investigates the usability of mobile device based on four different screen sizes and three styles interaction gestures; specifically, it focuses on the ergonomics factor of the user. Usability test was conducted to 100 university students in Indonesia who used mobile device regularly. Result found that screen size and interaction style affect the completion time and numbers of errors. Hand dimension significantly affect users' performance when they used one and two thumbs gestures. [ABSTRACT FROM AUTHOR]

Analog-to-digital converters (ADCs) are an important component in electronics design. One of the difficulties being faced is to be able to accurately and cost-effectively test the continually higher performance of ADCs under budget constraints. Test time for static linearity is a major portion of the total test cost. Our group proposed an ultrafast segmented model identification of linearity error (uSMILE) algorithm for estimating linearity, which reduces test time dramatically compared to the conventional method. However, this algorithm produces large estimation errors in low resolution ADCs (10-12 bits) when the input is a ramp signal, for which the quantization noise of ADC becomes a dominant part in the total noise. In this study, we propose three types of distribution dithering methods added to the ramp input signal to reduce the estimation error when uSMILE was applied to low resolution ADCs. Fixed pattern was proved to be the most efficient and cost-effective method by comparing with the Gaussian, uniform, and fixed-pattern distributions. The simulation results indicate that the estimation error can be significantly reduced in a 12-bit SAR ADC with effective dithering. Furthermore, a hardware evaluation board with commercial ADC products was used to validate the effectiveness of the fixed-pattern dithering methods, and our measurement shows the INL estimation error can be reduced to less than 0.1 LSB. Such dithering method relaxes the input requirement of uSMILE algorithm which dramatically reduces the test setup cost. [ABSTRACT FROM AUTHOR]

The design of high-performance adders has experienced a renewed interest in the last few years; among high performance schemes, parallel prefix adders constitute an important class. They require a logarithmic number of stages and are typically realized using AND-OR logic; moreover with the emergence of new device technologies based on majority logic, new and improved adder designs are possible. However, the best existing majority gate-based prefix adder incurs a delay of 2\mathbflo\mathbfg_2(\boldsymboln) - 1 (due to the \boldsymboln th carry); this is only marginally better than a design using only AND-OR gates (the latter design has a 2\mathbflo\mathbfg_2(\boldsymboln) + 1 gate delay). This paper initially shows that this delay is caused by the output carry equation in majority gate-based adders that is still largely defined in terms of AND-OR gates. In this paper, two new majority gate-based recursive techniques are proposed. The first technique relies on a novel formulation of the majority gate-based equations in the used group generate and group propagate hardware; this results in a new definition for the output carry, thus reducing the delay. The second contribution of this manuscript utilizes recursive properties of majority gates (through a novel operator) to reduce the circuit complexity of prefix adder designs. Overall, the proposed techniques result in the calculation of the output carry of an \boldsymboln -bit adder with only a majority gate delay of \mathbflo\mathbfg_2(\boldsymboln) + 1 . This leads to a reduction of 40percent in delay and 30percent in circuit complexity (in terms of the number of majority gates) for multi-bit addition in comparison to the best existing designs found in the technical literature. [ABSTRACT FROM AUTHOR]

A compact hybrid antenna structure with frequency reconfiguration capabilities is presented in this article. The proposed design employs a combination of a rectangular DR element and a coupling slot on the structure’s ground plane (GP). The slot shifts the fundamental DRA mode by introducing a slow wave effect and its resonant behavior helps to achieve an omnidirectional pattern at low frequencies. The slot is loaded with a series of PIN diode switches whose ON/OFF combinations alter the effective slot length. Slot loading with PIN diodes results in frequency reconfiguration of the proposed structure with a large tuning range of 76.2% (between 1.73 and 3.86 GHz). A parametric analysis was performed to investigate the effects of slot length, width, and position on the reflection coefficients of the proposed structure. A prototype of the proposed design was fabricated and results were measured. The measured results show a close agreement with the simulated ones. The proposed design is suitable for DCS 1800 MHz, PCS 1900 MHZ, UMTS, LTE 2500–2700 MHz, and Wimax 3.5 GHz. [ABSTRACT FROM AUTHOR]

This paper proposes an automatic any-cells-to-any-cells battery equalizer, which merges the forward and flyback converters through a common multiwinding transformer. The windings of the transformer are divided into two groups, which have opposite polarities. The principles of the proposed equalizer are that the equalization in one group is achieved based on forward conversion and the balancing between the two different groups is based on flyback conversion, by which the magnetic energy stored in the transformer can be automatically reset without using additional demagnetizing circuits. Moreover, only one MOSFET and one primary winding are required for each cell, resulting in smaller size and lower cost. One pair of complementary control signals is employed for all MOSFETs, and energy can be automatically and directly delivered from any high-voltage cells to any low-voltage cells without the requirement of cell monitoring circuits, thereby leading to a high balancing efficiency and speed. The proposed topology can achieve the global equalization for a long battery string through connecting the secondary sides of transformers without the need of additional components for the equalization among modules, which also overcomes the mismatching problem of multiple windings. The validity of the proposed equalizer is verified through experiments, and the balancing efficiency can reach up to 89.4% over a wide range of conditions. [ABSTRACT FROM PUBLISHER]

Teleoperation allows human operators to safely extend themselves to remote environments that are typically difficult or dangerous to access. The remote environments are often unstructured (i.e. not having clear roads or paths to follow) and only accessible by wireless communication (introducing factors such as degraded signals and communication delay). Teleoperated driving under these conditions can result in slow operation speeds and unintended collisions with obstacles. Automating portions of the teleoperation task can help mitigate some of the negative effects of wireless communication. Shared control is used to combine inputs from the human teleoperator and automation. This work presents a new model predictive control based shared control method. We introduce a new representation for obstacle free regions that works well with unstructured robot environments and allows for an model predictive control problem formulation that can be solved rapidly. The shared control method is implemented in a robot simulator and tested with human subjects. Two user studies involving a search task with a mobile robot evaluate the effectiveness of the shared control method and explore its interaction with factors such as communication delay and input interface style. Communication delay is found to have the largest magnitude effect on performance and safety measures. Results demonstrate that the shared control method can improve both performance and safety when delays are present. [ABSTRACT FROM AUTHOR]

In this paper, a comparative study between performance of BJT and CMOS technologies is performed by implementing two novel BJT and CMOS differential voltage current conveyors (DVCCs) with minimum and equivalent sizes. In this study, 'size' means the number of the transistors used in a design. The CMOS-DVCC consists of only 12 MOS transistors, and the BJT-DVCC includes 13 BJTs. The implementations are performed in Proteus-7 environment, and the two DVCCs are formulized with their real parameters. The two chips are modeled at low frequency, and it is shown that the CMOS-DVCC has acceptable performance and behavior to operate as a DVCC while the parameters of the BJT-DVCC are far from an ideal DVCC, so the CMOS-DVCC can be used to design electronic devices. The comparative analysis shows to achieve a reliable and acceptable BJT implementation of a DVCC, it is inevitable to increase the size of the BJT implementation. To prove this claim, another novel acceptable BJT-DVCC with larger size is presented and modeled. It is also demonstrated that the acceptable BJT-DVCC is also the first and only DVCC reported in the literature which is applicable to high-power applications, and this is the other contribution of this work. [ABSTRACT FROM AUTHOR]

Organic FETs (OFETs) are essential devices in future flexible electronics. Yet, a crucial issue associated with electronic contact is still unsolved and our fundamental understanding remains very limited. Unlike many other previous reports talking about the contact resistance, in this paper, we specifically discuss its major root: the Schottky barrier, by comparison of the conventional metal-silicon contacts, and the unconventional metal–organic contacts, where the special features in OFETs are underlined. We not only examine the basics of the Schottky barrier but also the extrinsic effects as well as the characterization methods. The key factors in device fabrication are also reviewed in order to minimize the detrimental impacts of the Schottky barrier for obtaining optimum device performance. [ABSTRACT FROM PUBLISHER]

This paper proposed an energy efficient adder employing multistage latency and approximate computing technology. The delay of the adder decreases after the critical path of the adder is divided into multiple short stages with series of predictors, then the approximate computing technology is exploited to make a tradeoff between output quality and energy efficiency. The proposed design is applied into discrete cosine transformation (DCT) in image processing and support vector machine (SVM) algorithm in machine learning to verify its availability, the simulation results demonstrate that the proposed approximate adder provides 25.6% power-delay-product (PDP) reduction and 2 orders of magnitude reduction in output error than the recent counterpart designs. Compared with the conventional accurate ripple carry adder (RCA) and Kogge stone adde (KSA), the proposed design presents 66.5% to 37.6% PDP reduction, at the cost of negligible output quality reduction, which are qualified as peak signal-to-noise ratio (PSNR) for DCT (decreases from 33.88dB to 33.84dB) and classification accuracy for SVM (decreases from 80.46% to 79.19%). [ABSTRACT FROM AUTHOR]

This study was aimed at the development of a non-intrusive, biosensor based, Adaptive Interface Design (AID) that utilizes its users' physical abilities (rather than focusing on their disabilities), while simultaneously honoring their integrity and needs. The target users for this study were patients with arthritis in the hand. The AID comprises of eye tracking and data glove technologies, the latter of which will be used to measure the user's physical ability as it translates hand gestures into computer controls. By developing accessible computer interfaces and exploring their use for telerehabilitation purposes, we want to ultimately impact the inclusion and health outcomes of those who experience disability on a daily basis. [ABSTRACT FROM AUTHOR]

This paper aims at designing a scanning keyboard that serves people with paralysis. This keyboard works on detection and tracking of the user eyeball movements. The main objective of this research work is to implement a simple and less expensive technique that produces the best possible results with a higher level of accuracy. The design of the system is done in phases; these are eye detection and tracking, followed by classification. The tracking phase incorporates skin color segmentation, black pupil detection and support vector machines. We also explored the role of eye red-channel, eye width and height for eye tracking. A scanning keyboard is developed and tested to work with three eyeball movements with 90% double detection accuracy. The performance of the algorithm is experimentally analyzed and the benefits of the proposed approach are highlighted. Also, the simulation results are presented. [ABSTRACT FROM AUTHOR]

Existing Data Center Network (DCN) architectures are classified into two categories: switch-centric and server-centric architectures. In switch-centric DCNs, routing intelligence is placed on switches; each server usually uses only one port of the Network Interface Card (NIC) to connect to the network. In server-centric DCNs, switches are only used as cross-bars, and routing intelligence is placed on servers, where multiple NIC ports may be used. In this paper, we formally introduce a new category of DCN architectures: the dual-centric DCN architectures, where routing intelligence can be placed on both switches and servers. The dual-centric philosophy can achieve various tradeoffs in designing DCN architectures. We propose three novel dual-centric DCN architectures: FCell, FRectangle, and FSquare, all of which are based on the folded Clos topology. FCell is a power-efficient DCN architecture, with a larger diameter and lower bisection bandwidth than FSquare and FRectangle. FSquare is a high performance DCN architecture, in which the diameter is small and the bisection bandwidth is large; however, the DCN power consumption per server in FSquare is high. FRectangle significantly reduces the DCN power consumption per server, compared to FSquare, at the sacrifice of some networking performances. By investigating FCell, FRectangle and FSquare, and by comparing them with existing architectures, we demonstrate that, the three novel dual-centric architectures enjoy the advantages of both switch-centric designs and server-centric designs, have various nice properties for practical data centers, and provide flexible tradeoff choices in designing DCN architectures. [ABSTRACT FROM PUBLISHER]

The main aim of this paper is to present a detailed description of the research related to the modeling of heat conduction in modern electronic structures, including special consideration for numerical aspects of analyzed algorithms. The motivation to undertake the research as well as some of the most-important results of the experiments and simulations are also included. Moreover, a numerical approximation of the problem as well as the methodology used and a sample solution of the mentioned problem are presented. In the main part, the discretization techniques, Ordinary Differential Equation algorithms, and simulation results for Runge-Kutta's and Gear's algorithms are analyzed and discussed. Additionally, a new effective approach to the modeling of heat transfer in electronic nanostructures is demonstrated. [ABSTRACT FROM AUTHOR]

Spatial audio has been at the core of the multimodal experience at the AlloSphere, a unique instrument for data discovery and exploration through interactive immersive display, since its conception. The AlloSphere multichannel spatial audio design has direct roots in the history of electroacoustic spatial audio and is the result of previous activities in spatial audio at the University of California at Santa Barbara. A concise technical description of the AlloSphere, its architectural and acoustic features, its unique 3-D visual projection system, and the current 54.1 Meyer Sound audio infrastructure is presented, with details of the audio software architecture and the immersive sound capabilities it supports. As part of the process of realizing scientific and artistic projects for the AlloSphere, spatial audio research has been conducted, including the use of decorrelation of audio signals to supplement spatialization and tackling the thorny problem of interactive up-mixing through the Sound Element Spatializer and the Zirkonium Chords project. The latter uses the metaphor of geometric spatial chords as a high-level means of spatial up-mixing in performance. Other developments relating to spatial audio are presented, such as Ryan McGee's Spatial Modulation Synthesis, which simultaneously explores the synthesis of space and timbre. [ABSTRACT FROM AUTHOR]

Experiments were conducted to study the thermal performance of meshed wick heat pipe by varying the working fluid and heat input. In this work four screen mesh wicked heat pipes were fabricated and tested. All the heat pipes were tested for heat input from 50 W to 250 W each with an increment of 50 W in each step. The heat input range selected in this study is commonly encountered in most of the electronic application devices. The thermal resistance of all the heat pipes charged with different working fluids such as de-ionised water, Al2O3/de-ionised water nanofluid of volume concentration 0.1%, and hybrid nanofluid volume concentration 0.1%, with two different combinations of (Al2O3 50%-CuO 50%)/de-ionised water and (Al2O3 25%-CuO 75%)/de-ionised water, was determined. The maximum percentage reduction was found to be 58.87% for the hybrid nanofluid of (Al2O3 25%-CuO 75%)/de-ionised water compared to base fluid. An important observation from the study is that, use of hybrid nanofluid can raise the operating range of the heat pipe beyond 250 W which makes hybrid nanofluid as a potential substitute for the conventional working fluid. [ABSTRACT FROM AUTHOR]

Rapid developments in the design of chips and electronic devices for high-performance computers have led to a need for new and more effective methods of chip cooling. The purpose of this study was to investigate the heat transfer development and characteristics of the aluminum foam heat sink for Intel core i7 processor. The aluminum foam heat sink was subjected to a steady flow of water covering the non-Darcy flow regime (297–1353 Reynolds numbers). The bottom side of the heat sink was heated with a heat flux between 8.5 and 13.8 W/cm 2 . The heat development and thermal entry length of the aluminum foam heat sink were examined and presented. The distributions of the local surface temperature and the local Nusselt number were measured and compared with the numerical data obtained using finite element method. The average Nusselt number was obtained for the range of Reynolds numbers and an empirical correlation of the average Nusselt number as a function of the Reynolds number was derived. A comparison of previous studies using water as a coolant through aluminum foam was conducted in order to calibrate the empirical correlation of the average Nusselt number. The pressure drop across the foam was measured. The thermal performance of aluminum foam heat sink was evaluated based on the average Nusselt number and the required pumping power. The experimental results revealed that the thermal entry length increases along with increases in the Reynolds number. The results also revealed that local surface temperature increases as the heat flux increases, decreasing the Reynolds number and increasing the flow direction axis. In the fully developed region, the local Nusselt number is strongly dependent on the Reynolds number. The thermal efficiency index was defined in the study in order to evaluate the thermal performance for the aluminum foam heat sink. The results were also compared with those of previous experimental studies that used air as a coolant. The results indicated that, as a coolant, water provides lower average surface temperatures and a more uniform temperature profile. The numerical results were in good agreement with the local Nusselt number and the local experimental temperature with a maximum relative error of 0.83% and 0.43%, respectively. [ABSTRACT FROM AUTHOR]

This paper describes an ongoing study related to a conceptual design model, which is specific to instructional interface design to enhance courseware usage. It was found that most of the existing courseware applications focus on the needs of certain target with most of the courseware offer too little to inclusive learners. In addition, the use of structure, layout, and navigation to improve the courseware instructional interfaces as part of usability strategies was also problematic for developers. Thus, this study aims at creating an alternative instructional interface as part of usability strategies for inclusive education systems called Instructional Interface Design for Courseware (IID4C). It is proposed as guidance for the developer to refer to. The study used comparative analysis technique to determine the elements of the model. In the end, this study finds that the IID4C model is useful for information accessibility and contributes to the designing of instructional courseware. Future works are to evaluate the proposed model among disabled and non-disabled learners. [ABSTRACT FROM AUTHOR]

Background: Audit and Feedback (A&F) is a widely used quality improvement technique that measures clinicians' clinical performance and reports it back to them. Computerised A&F (e-A&F) system interfaces may consist of four key components: (1) Summaries of clinical performance; (2) Patient lists; (3) Patient-level data; (4) Recommended actions. There is a lack of evidence regarding how to best design e-A&F interfaces; establishing such evidence is key to maximising usability, and in turn improving patient safety.Aim: To evaluate the usability of a novel theoretically-informed and research-led e-A&F system for primary care (the Performance Improvement plaN GeneratoR: PINGR).Objectives: (1) Describe PINGR's design, rationale and theoretical basis; (2) Identify usability issues with PINGR; (3) Understand how these issues may interfere with the cognitive goals of end-users; (4) Translate the issues into recommendations for the user-centred design of e-A&F systems.Methods: Eight experienced health system evaluators performed a usability inspection using an innovative hybrid approach consisting of five stages: (1) Development of representative user tasks, Goals, and Actions; (2) Combining Heuristic Evaluation and Cognitive Walkthrough methods into a single protocol to identify usability issues; (3) Consolidation of issues; (4) Severity rating of consolidated issues; (5) Analysis of issues according to usability heuristics, interface components, and Goal-Action structure.Results: A final list of 47 issues were categorised into 8 heuristic themes. The most error-prone heuristics were 'Consistency and standards' (13 usability issues; 28% of the total) and 'Match between system and real world' (n=10, 21%). The recommended actions component of the PINGR interface had the most usability issues (n=21, 45%), followed by patient-level data (n=5, 11%), patient lists (n=4, 9%), and summaries of clinical performance (n=4, 9%). The most error-prone Actions across all user Goals were: (1) Patient selection from a list; (2) Data identification from a figure (both population-level and patient-level); (3) Disagreement with a system recommendation.Conclusions: By contextualising our findings within the wider literature on health information system usability, we provide recommendations for the design of e-A&F system interfaces relating to their four key components, in addition to how they may be integrated within a system. [ABSTRACT FROM AUTHOR]