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This paper presents a new transistor self-oscillating inverter suitable for high efficiency switch mode power supplies, which can operate directly from high voltages and is free from output transformer saturation problems due to transistor characteristic mismatch. It uses a half-bridge power circuit, consisting of two transistors in one limb and two capacitors in the other. Amongst several advantages of this configuration, the switching transistors need to withstand a minimum voltage equal to the dc supply only and not higher as in conventional circuits, while using only two transistors.

This paper proposes a design method of the feed- forward controller to improve on the non-interference control performance of a single-phase AC/DC PWM converter in parallel for high speed trains. The feed-forward controller compensates interference phenomenon generated by switching converter in parallel. As the secondary leakage inductance in transformer is changed by operating conditions of the trans- former, the gain value of feed-forward controller is calculated by estimating the changed leakage inductance. The estimation procedure of the boost inductance is only based on the variation of input current and the input AC voltage measurement. The estimated boost inductance is optimized by the least square method. Then the controller with gain value can exactly compensate the interference phenomenon. The validity of proposed technique is verified through the MATLAB Simulink simulation results.

This demo paper presents a new sensor focusing on the measurement of real time foot plantar pressure distribution. IEE S.A. releases a single insole-solution for daily usage in order to acquire information on the plantar load dispersion in a large range of shoe configurations. The new High-Dynamic Force-Sensing Resistor (HD-FSR) multi-cell smart insole sensor enables advanced real-time gait analysis applications.

Background: In a previous paper, we have demonstrated that: (1) local injection of corticosteroids for carpal tunnel syndrome (CTS) is as effective as decompressive surgery, at 1-year follow-up; and (2) surgery has an additional benefit in the 2-year follow-up. In this study, we assess the long-term outcomes of both therapies in an observational extension of the patients originally enrolled in our randomized clinical trial. Methods: Patients were included in an open, randomized clinical trial, comparing injections versus surgery in CTS. After the end of the clinical trial, patients received the treatment prescribed by their general practitioner or specialist. Therapeutic failure was defined as the need of any new therapeutic intervention on the involved wrist. Comparison between groups was made using Cox multiple regression analysis. Estimation of the accumulated incidence of new therapeutic failure was made considering the withdrawal as a competitive risk (Gooley’s test). Results: Of 163 randomized wrists at the beginning of the study, only 148 were available at the final follow-up. The mean follow-up was 6.3 and the median was 5.9 years. In the long-term follow-up, the accumulated incidence of therapeutic failure in the surgery group was 11.6% versus 41.8% in the injection group. The Cox multiple regression analysis showed a risk of failure associated with injection group of 4.5 (95% confidence interval [CI], 2.1-9.8; P < .0001). Conclusions: In long-term follow-up, surgery seems more effective than local corticosteroid injections in primary CTS. Nonetheless, about 58% of the patients in the injection group will not need further therapeutic interventions during the follow-up.

For the realization of future wireless networks, gigabit wireless technology which can achieve higher-than-1Gbps data transmission with extremely low transmit power is indispensable. We have been studying the distributed antenna network (DAN) and the frequency-domain wireless signal processing. In DAN, many antennas or clusters of antennas are spatially distributed over a service area and they are connected by means of optical fiber links with DAN signal processing center (SPC). A number of distributed antennas cooperatively serve mobile users using spatial multiplexing, diversity, array or relaying technique. In this paper, the recent research advances of gigabit DAN and its related wireless techniques are introduced.

Magnetic circuit components have long been the largest and most difficult components to miniaturize. Printed circuit board (PCB) fabrication methods cannot achieve small diameter, high aspect-ratio vias for high winding turn numbers to achieve high inductance, and microelectronics methods cannot achieve the high-quality and thick ferrite core materials. In this paper, we present an alternative breakthrough method of printed circuit fabrication to significantly reduce the effective via diameter for embedded magnetic devices, boosting the inductance per unit area. To reduce the effective via diameter, high-density via plugs are ex-situ fabricated and shaped, and then embedded into PCB substrate in the same process as standard magnetic core embedding. The structure of the plug is such that precise placement within the substrate, or alignment to the plug with the winding pattern, is not necessary. Devices presented in this paper use via plugs with an effective diameter of 40 μm and a theoretically unlimited aspect ratio, though refinements in the plug fabrication process are expected to reduce the via diameter down to 10μm. The process is experimentally demonstrated with a 14-turn racetrack shaped transformer; novel diagnostic methods using magneto-optic garnet films to image current paths are also demonstrated.

Combustion turbines and combined cycles have become a dominant mode of new capacity addition in most parts of the world. However, to maximize the benefits of a combined cycle, it must be designed to take into account site-specific technical, economic, and environmental considerations. This paper outlines the important design considerations that must be addressed in the early stages of a project's development.

This paper will show how turbulence plays a leading role in the design of space launching systems. It presents several areas for which turbulent flows represent critical issues either for the reliability of the systems or for their operational performance. Turbulence is a leading physical phenomenon involved in both the external aerodynamics of space vehicles as well as in the operation of their propulsive systems. Physical issues concern, for instance, unsteady low-velocity and large-scale atmospheric aerodynamics, subsonic, trans-sonic and supersonic vehicle aerodynamics, re-entry aerothermodynamics, single- and multiple-phase mixing and combustion, aerodynamics and hydraulics of turbomachinery. The mastering of these complex phenomena is a critical challenge for the space industry if it is to propose, in the future, reliable and high-performance systems with ambitious low-cost objectives. This article was chosen from Selected Proceedings of the 1st French Seminar on Turbulence and Space Launchers (CNES...

A defining characteristic of the Internet of Things (IoT) is pervasive collection and linkage of user data to provide personalised experiences. To enable this functionality, IoT devices and services must be connected and share data about users' interactions with multiple nodes in the network. Consistent identification of users and devices across the network is likewise necessary. These aspects of the IoT can pose risks to user privacy. Potentially invasive inferences can be drawn from linked datasets, including data generated through usage of connected devices and services. The forthcoming General Data Protection Regulation (GDPR) contains numerous provisions relevant to the risks posed by identification technologies. However, the strict legal requirements defined in the Articles of the GDPR may be insufficient to ensure a fair balance is struck between user's interests in privacy and the interests of IoT developers and data controllers. To address this gap, this paper proposes a three-step transparency model based on known privacy risks of the IoT, weaknesses in relevant legally binding provisions in the GDPR, and the GDPR's governing principles. Eleven guidelines aimed at IoT developers and data controllers are described addressing how information about the functionality of IoT devices and services should be shared with users. The guidelines describe ethically desirable standards to be adhered to in addition to the GDPR's legally binding requirements. To demonstrate how the guidelines could apply in practice and alter the design choices and practices of IoT developers and data controllers, connected cars are considered as a use case.

Small renal tumor is a radiologically detected renal mass up to four cm in diameter. Surgery is the main therapeutic option in the treatment of these tumors, but in elderly and comorbid patients ablative techniques are the alternative. The aim of this paper is to report our experience in the treatment of small renal tumors with ablative techniques. We retrospectively analyzed patient records of individuals treated with radiofrequency and microwave ablation at the University hospital center Zagreb in the period from January 2017 to August 2019. An appropriate radiological and preoperative work-up was performed for all subjects, and then tumor biopsy and ablation. Patients were followed using the standard follow-up schedule: three, six, and 12 months after the procedure, and then annually, using radiological methods. Ablation of 32 small renal tumors was performed for 31 patients, 27 of which were radiofrequency and seven microwave ablations. One-year overall and cancer specific survival was 100%. In 12.9% of patients a residual mass was diagnosed – three were retreated with ablation and one underwent radical nephrectomy. We had four ClavienDindo grade 2 complications. Ablative techniques are an oncologically effective and safe treatment option for patients that are unfit for surgery.

Northrop Grumman Aerospace System has been developing High Power Lasers for the past 30 years. Area of concern with these high power lasers has always been laser safety. In recent years, NGAS has been successful in developing the megawatt chemical laser such as the Airborne Laser, and kilowatt class solid state laser such as the Joint High Power Solid-State Laser. We have not experienced any significant personnel injury, which we attribute to the lessons learned and the implementation of these safety lessons in these various projects. These various high power lasers that NGAS are developing involve the emission of laser beams into the air, land, water, and the laboratory. This paper will describe the various administrative and engineering measures we have implemented which allow us to operate the lasers safely in these various environments.Northrop Grumman Aerospace System has been developing High Power Lasers for the past 30 years. Area of concern with these high power lasers has always been laser safety. In recent years, NGAS has been successful in developing the megawatt chemical laser such as the Airborne Laser, and kilowatt class solid state laser such as the Joint High Power Solid-State Laser. We have not experienced any significant personnel injury, which we attribute to the lessons learned and the implementation of these safety lessons in these various projects. These various high power lasers that NGAS are developing involve the emission of laser beams into the air, land, water, and the laboratory. This paper will describe the various administrative and engineering measures we have implemented which allow us to operate the lasers safely in these various environments.

Hybrid networks are networks capable of switching data at multiple levels (optical and IP packet level) by means of multi-service optical switches. As a result of that, huge flows at the IP-level may be moved to the optical-level, which is faster than the packet-level. Such move could be beneficial since congested IP networks could be off-loaded, leaving more resources for other IP flows. At the same time, the flows switched at the optical-level would get better Quality of Service (QoS). In order to achieve this beneficial move, huge IP flows have to be properly detected at the packet-level and lambda-connections are to be established for them at the optical-level. Two approaches are currently used for that purpose: the first is based on conventional management techniques and the second is based on GMPLS signaling. Both approaches mostly depend on human intervention, which can be error prone and slow. The idea proposed in this paper to overcome this problem consists of adding self-management capabilities to the multi-service optical switches. The optical switches would then be responsible for automatically identifying IP flows, and establishing and releasing lambda-connections for such flows. The main goal of this paper is therefore to propose an architecture for the self-management of lambda-connections in hybrid networks.

Single chip processor performance has improved dramatically since the inception of the four-bit microprocessor in 1971. This is due in part to technological advances, (i.e., faster devices and greater device density), but also because of the adoption of architectural approaches well suited to the opportunities and limitations of VLSI. The most appropriate are those that effectively reduce off-chip memory accesses and admit to a regular pipelined implementation. The over-riding goal of pipelining is to achieve “single cycle execution”, i.e., instructions appear to execute in a single processor cycle. Today’s RISC processors are close to realizing this goal, and the next generation will reduce the cycles per instruction even further. In this paper, we will review the design issues and the proposed architectures for high performance VLSI processors.

In this paper, we investigated a buffer-aided decode-and-forward (DF) wireless relaying system over fading channels, where the source and relay harvest radio-frequency (RF) energy from a power station for data transmissions. We derived exact expressions for end-to-end throughput considering half-duplex (HD) and full-duplex (FD) relaying schemes. The numerical results illustrate the throughput and energy efficiencies of the relaying schemes under different self-interference (SI) cancellation levels and relay deployment locations. It was demonstrated that throughput-optimal relaying is not necessarily energy efficiency-optimal. The results provide guidance on optimal relaying network deployment and operation under different performance criteria.

Using conventional robots for MIG (Metal/Inert-Gas) arc welding on thin (1 to 2 mm) sheet steel pressings is restricted by the difficulty of maintaining accurate fit-up and fixturing. Dimensional variations are introduced by wear of tools and fixtures, effects of variable springback in sheet steel pressings, and thermal distortion during welding. These variations cause errors in the position of the welding torch with respect to the seam of up to ± 3.0 mm, which prevents the formation of good welds. This paper gives a very brief description of our first implemented system that forms and uses semantic models for the automatic visually-guided control of a MIG welding robot. The system uses its models to detect the following dimensional variations in thin sheet steel assemblies: gap width, stand-off error, and lateral error. Lap-, T-, and butt-joints are dealt with. Due to the semanticallybased visual feedback technique reported in this paper, errors in the position of the welding torch are corrected to less than ± 0.3 mm, which is a suitable tolerance for producing good welds in such pressings. Furthermore, gap widths are detected for the purpose of dynamically altering welding parameters.

This paper presents outcome of a research which investigates the fatigue behaviour of duplex stainless steel grade (EN 1.4162) via cyclic tests on welded cruciform joints and base plates. A database of experimental tests for similar high-strength steel details was also collated from the literature. The obtained experimental S-N curve was then compared to the current European design ones and re-evaluated according to the hot spot stress method. A good agreement was observed between the studied detail performance and the collated reference data. Improvement to the fatigue design rules for the studied duplex and similar high-strength steel details is then proposed. ispartof: Engineering Structures vol:247 status: Published online

Light-gauge Steel Framed (LSF) floor panels are commonly employed in conventional and modular building constructions on the basis of their lightweight nature. Previous research studies on the fire performance of LSF floor panels have been limited to Cold-Formed Steel (CFS) lipped channel and hollow flange joists. Therefore, there is a need for research on the fire performance of the LSF floor panels designed with optimised CFS joists in conventional floor panels and modular floor panels. This paper focuses on the fire performance of LSF conventional and modular floor panels made of optimised CFS joists found in the literature, using Finite Element (FE) analyses. Heat transfer FE models of LSF floor panels were developed and validated against the data available in the literature. Subsequently, the validated FE models were extended to investigate the LSF conventional and modular floor panels made of optimised CFS joists. In total 32 different LSF modular and conventional panels were analysed. A load ratio-critical average joist temperature relationship was derived based on the past test results and extensive FE results. The established relationship in conjunction with time-temperature profiles from the FE analysis was used to predict the Fire Resistance Rating (FRR) of the LSF conventional and modular floor panels made of optimised CFS joists. The results showed that modular floor panels withstand significant standard fire loading compared to the conventional floor panels while optimised CFS joists can also be used to enhance the fire performance.

Background: Empirical evidence pertaining to the influence of treatment preferences on attrition, adherence and outcomes in intervention evaluation trials is inconsistent. The inconsistency can be explained by the method used for allocating treatment and measuring preferences. The current methodological study is designed to address these factors by implementing the two-stage partially randomized or preference trial design, and administering a validated measure to assess participants’ preferences for the treatments under evaluation. It aims to compare attrition, adherence and outcomes for participants allocated randomly or by preference to treatment. The study is in its final stages of data collection; its protocol is presented in this paper. Methods/Design: A partially randomized clinical or preference trial is used. Eligible participants are randomized to two trial arms. First is the random arm involving random assignment to treatments, and second is the preference arm involving allocation to the chosen treatment. Participants with chronic insomnia are targeted. Two behavioral treatments are offered, stimulus control therapy and sleep restriction therapy, in the same format (small group) and dose (two sessions given over a 4-week period). A participant log is used to collect data on attrition. Adherence is evaluated in terms of exposure and enactment of treatment. Sleep-related outcomes (sleep parameters and perceived insomnia severity) are measured at pretest, posttest, 6 and 12 month follow-up. Treatment preferences, adherence and outcomes are assessed with reliable and valid measures. Discussion: The advantages and limitations of the preference trial design are highlighted. The challenges in implementing the trial are discussed relative to the distribution of participants in the groups defined by treatment received and method of treatment allocation. Trial registration: ClinicalTrials.gov Registry NCT02513017

Objective: To update an earlier observational study (1980–1995) documenting dramatic improvements in the management of croup with the mandatory use of a single oral dose of dexamethasone and to ascertain whether a reduction from a dose of 0.6 to 0.15 mg/kg in 1995 maintained these improved outcomes over the next 11 years. Methods: We evaluated retrospectively the experience of children with croup in Princess Margaret Hospital for Children, the only tertiary paediatric hospital in Western Australia, over the subsequent 11 year period from 1996 to 2006 inclusive. Data were updated from ED, general hospital and the intensive care unit records to show the numbers of children presenting to the hospital, admitted, transferred to intensive care and intubated. We also recorded the length of hospital stay and representation rate of all cases within 7 days. Results: The dramatic improvements in outcomes for croup, including reduced admission rates, length of stay, transfers to the intensive care unit, intensive care unit days and number of intubations as reported in our earlier paper, were maintained using 0.15 mg/kg dexamethasone. Admission rates for croup have fallen from 30% in the early 1990s to less than 15% in recent years, whereas the representation rate has risen slightly. Conclusion: The improved outcomes for children with croup presenting to our paediatric ED have been maintained with a reduced, single oral dose of 0.15 mg/kg of dexamethasone.

In this paper a low-cost and low-weight attitude estimation system for an autonomous helicopter is presented. The system is based on an inclinometer and a rate gyro. The data coming from the sensors is fused through a complementary filter. In this way the slow dynamics of the inclinometer can be effectively compensated. Tests have shown that a very effective attitude estimation system can be achieved.

The steep voltage slopes of today’s wide-bandgap (WBG), fast-switching power semiconductors — like SiC and GaN — lead amongst other challenges to reflection on long cables and thereby overvoltage at inductive loads. To enable the use of these inverters with motors without specially reinforced insulation the voltage slopes need to be slowed down. This article presents a new low-loss countermeasure, which involves the parallel connection of two half-bridges via an interphase transformer. For this one half-bridge is delayed relative to the other one by a delay tuned to a resonant circuit. Undesired DC components in the cross-current of the interphase transformer occur due to non-idealities in the voltage symmetry. The subsequent DC magnetization ultimately can cause the core to saturate. The paper describes the effects due to inaccurate timings and the aspects to keep in mind when dimensioning the magnetic core. Also, this article describes an approach to deal with the undesired current components using a closed-loop control. For that, a special differential-mode shunt is used which enables a dedicated measurement of the cross-current mean value and mitigates the influence of the switching frequency. Finally, the controller concept is presented. The controller is implemented and verified on a 500 kVA SiC inverter test bench.

This paper studies the coordinated use of smart inverters with legacy voltage regulating devices to help increase the energy savings from conservation voltage reduction (CVR) in distribution systems with high photovoltaic penetration. Two voltage optimization algorithms are developed to evaluate the CVR benefit by considering two types of smart inverter functions: aggregated reactive power control and autonomous volt/VAR control. In each algorithm, smart inverters are coordinately controlled with the operation of legacy voltage regulating devices including load tap changers and capacitor banks. Both algorithms are tested on representative utility distribution system models. Simulation results demonstrate that the proposed algorithms can achieve around 1.8-3.6% energy savings when only using legacy voltage regulating devices and an additional 0.3-0.9% when adding smart inverters.

Distributed energy resources connected to distribution systems are vulnerable to islanding events and single-phase open. These two events have in common a circuit opening, and it is possible that single-phase opening events result in variations of frequency and voltage that cause protection actuation. Thus, to evaluate the similarity of islanding and single-phase events, this paper presents the non-detection zone to protection functions during events of single-phase open and three-phase open switch. Moreover, different connections of loads and transformer are considered to identify its influence. The results show that in cases where single-phase opening is considered, usually the number of undetectable points is higher than the cases of three-phase opening, and depending on the setting, the rate of change of frequency function trips to SPO and TPO events and the voltage unbalance function can be used to detect SPO events.

This paper proposes a novel self balancing 7 level inverter with two coupled inductors. The proposed inverter can generate 7 levels with only one DC source. By series charging and parallel discharging of capacitors, it can self balance the voltage across the two capacitors. The proposed topology incurs a lower part count compared to existing (conventional) topologies and can self balance the voltage across capacitors without any extra balancing circuit with simple control strategy. Because of high frequency coupled inductors, the dead band between some of the power switches can be eliminated and output voltage distortion is low. A 1200W power rating system has been simulated to verify the viability of the proposed topology and the relevant simulation waveforms are included.

Nowadays the doubly fed induction generator is often used in high power wind energy conversion systems. A common problem of converter fed induction machines are the bearing damages due to the bearing currents. The source of this problem is the common mode voltage caused by the fast switching converters. Instead of a passive solution like EMI filters or insulated bearings, this paper presents a control method based on the direct power control combined with an advanced commutation strategy to avoid the common mode voltage. This control strategy needs no space vector modulation and further no knowledge of system parameters like stator resistance. Only the direction of the phase currents must be determined by an additional circuit. Experimental results for a 4kW DFIG system illustrates the effectiveness of the proposed method.

Tire shreds have gained wide acceptance as an engineered fill in the last two decades. Ladder-type metal reinforcement can be used to reinforce MSE walls with tire shred-sand mixtures as a backfill material. This paper reports the results of laboratory pullout testing performed on ladder-type metal reinforcement embedded in tire shred-sand mixtures. The ladder-type metal reinforcement consists of two parallel longitudinal steel bars welded to a series of cross bars forming rectangular apertures. Mixtures of Ottawa sand with 50–100 mm size tire shreds were prepared at different mixing ratios (0%, 20%, 25%, and 35% by weight of tire shreds). Pullout tests were performed under three normal stresses – 40 kPa, 65 kPa, and 90 kPa. The test results show that the ladder-type metal reinforcement provides higher pullout resistance in tire shred-sand mixtures than in sand alone. Compared to metal-strip reinforcement, ladder-type metal reinforcement provides higher pullout capacity due to the passive resistance that results from the interlocking of tire shreds within the grids of the ladder-type reinforcement. The pullout resistance increased with increasing tire shred content up to 35% (by weight of tire shreds), beyond which segregation of the mixtures was observed.

A key contributor to excessive energy usage in UK domestic dwellings is the poor temperature regulation of fluid filled heat emitters that form the most common constituent of central heating systems. This is in-part due to oversizing of the heat emitters, and deficiencies in localised closed-loop temperature control. In an attempt to address this, Controllable Radiator Valves (CRVs) are becoming an increasingly popular domestic technology with the ability to allow previously unrealisable control schemes to operate the traditional central heating system with minimal mechanical modification. Following previous reported work, therefore, this paper presents a new family of Recursive Modelling Model Predictive Controllers (RM-MPCs) for use with low cost thermic CRVs. The ability of the presented control methodologies to maintain superior temperature regulation despite the use of oversized heat emitters, is a key contribution of the paper. Furthermore, unlike previously reported techniques, the underlying recursive modelling method has been reformulated so that traditional parameter matching calculations do not now require a computationally intensive curve fitting stage. A comparison of techniques is included using experimental measurements from both an oversized oil filled heat emitter within a test chamber, and also from BS EN 442 water-filled heat emitters within an occupied dwelling. Results show the proposed methodologies can be realised using more cost-effective thermoelectric valves, whilst providing superior set point tracking.

The paper presents an automatic procedure for the design optimisation of a synchronous reluctance motor with a flux barrier rotor that combines the finite element analysis (FEA) with an optimisation routine. The aim of the optimisation is the improvement of the torque and it is carried out considering two different design strategies. The proposed procedure allows definition of the rotor geometric dimensions starting from an existing motor or a preliminary design.

This paper focuses on methods of achieving direct field orientation (DFO) of induction machines based on closed-loop, stator, and rotor flux observers which are well suited to both zero and very high-speed operation. Both observer topologies are dominated by a current model at zero and low speeds, and a voltage model at high speeds. Application of such rotor and stator flux observers to both stator and rotor direct field orientation is presented, including experimental results for three different methods. The influence which flux regulation has on parameter sensitivity of the complete DFO system is analyzed. A rotor-flux-regulated and -oriented system is shown to be sensitive to leakage inductance under high slip (i.e., field weakened) operation. Both a stator-flux-regulated and -oriented system and a stator-flux-regulated, rotor-flux-oriented system are shown to have reduced parameter sensitivity at high speeds. Unlike stator flux orientation using simple voltage integration stator flux models, excellent zero and low-speed operation of an observer-based stator-flux-oriented system is demonstrated. >

A domestic water heating system that combines photovoltaic thermal (PVT) solar collectors with two heat pumps, in a novel cascade arrangement, is presented and analyzed in this paper. The goal of this analysis is to determine and compare the annual thermal energy output of the PVT cascade heat pump system with an evacuated tube and simultaneous consumption PVT single heat pump water heating system. The computational technique that was developed to analyze the PVT cascade heat pump system, which determines solar panel energy outputs, and heat pump operating characteristics, is described in detail. Case study simulation results are also presented, which include transient power output profiles, temperature profiles, and yearly energy output results. Hourly weather data, including air dry-bulb temperatures and solar flux values, from locations with a range of climates was used in these simulations. The results of this study show that the PVT cascade heat pump system has an annual thermal energy output improvement over the evacuated tube heating system ranging from 37% to 68%, depending on the selected simulation location.

This paper presents for the first time the design and characterization of an ultra-compact 3-axis roll-pitch-yaw gyroscope which employs a single vibrational element with a torsional drive mode and a multi-directional sense modes. Implemented in wafer-level Epitaxial Silicon Encapsulation (Epi-Seal) process, device occupies an area of 1.2 mm2. Initial characterization reported in this paper includes a scale factor, a noise level, and a cross-axis error measurement.

Power components such as High Electron Mobility Transistors (HEMTs) are used for high power and high frequency applications. These tend to overheat and destroy their packaging and connections to the wire bondings. This paper presents planar micro-thermoelectric sensors (μTESs) developed to measure partial heat flow dissipated by the HEMTs to avoid the HEMTs from reaching critical temperatures. These sensors use the same active materials as well as the same fabrication process as the HEMTs, enabling them to be fabricated simultaneously for a simple integration. The HEMTs’ active layers consist in AlGaN/GaN heterostructures resulting in the formation of a 2D Electron Gas (2DEG) at the interface. Tension factors of 47 mV/(K.mm2) were obtained with these sensors and heat flows of 0.2 W to 7 W were measured.

The paper discusses the active delivery of a drug (methylene blue solution) through the Er:YLF-laser-perforated nail plate using pulsed radiation of microsecond Yb,Er:Glass laser. Different methods of laser impact on liquid drug are considered: by focused and diverging laser beam. It was established that both discussed methods can provide sufficient dose of the drug for the treatment of onychomycosis.

In VANETs, it is important to support fast and reliable multi-hop broadcast for safety-related applications. The performance of multi-hop broadcast schemes is greatly affected by relay selection strategies. However, the relationship between the relay selection strategies and the expected broadcast performance has not been fully characterized yet. Furthermore, conventional broadcast schemes usually attempt to minimize the waiting time difference between adjacent relay candidates to reduce the waiting time overhead, which makes the relay selection process vulnerable to internal interference, occurring due to retransmissions from previous forwarders and transmissions from redundant relays. In this paper, we jointly take both of the relay selection and the internal interference mitigation into account and propose a fast, reliable, opportunistic multi-hop broadcast scheme, in which we utilize a novel metric called the expected broadcast speed in relay selection and propose a delayed retransmission mechanism to mitigate the adverse effect of retransmissions from previous forwarders and an expected redundancy probability based mechanism to mitigate the adverse effect of redundant relays. The performance evaluation results show that the proposed scheme yields the best broadcast performance among the four schemes in terms of the broadcast coverage ratio and the end-to-end delivery latency.

This paper presents a framework for telepresence operation by touching live video on a touchscreen. Our goal is to enable users to use a smartpad to teleoperate everyday objects by touching the objects live video they are watching. To this end, we coined the term teleinteractive device to describe such an object with an identity, an actuator, and a communication network. We developed a touchable live video image-based user interface (TIUI) that empowers users to teleoperate any teleinteractive device by touching its live video with touchscreen gestures. The TIUI contains four modules touch, control, recognition, and knowledge to perform live video understanding, communication, and control for telepresence operation. We implemented a telepresence operation system that consists of a telepresence robot and teleinteractive devices at a local site, a smartpad with the TIUI at a remote site, and communication networks connecting the two sites. We demonstrated potential applications of the system in remotely controlling telepresence robots, opening doors with access control panels, and pushing power wheelchairs. We conducted user studies to show the effectiveness of the proposed framework.

Stress management interventions (SMIs) can alleviate the psychosocial stress often experienced by women with heart failure. The purpose of this meta-analysis was to summarize women's participation rates, and predictors of participation, in SMIs for the management of psychosocial distress in women with chronic HF. Studies were retrieved from bibliographic databases, reference sections of relevant papers, and research registries. Included studies (a) evaluated a SMI approach for the management of chronic HF, (b) sampled chronic HF patients, and (c) used a randomized controlled trial (RCT) design. Independent coders extracted the relevant data. Thirty-five RCTs met inclusion criteria (N = 3,649; mean age = 63.5 ± 7.0 years). All studies sampled both men and women; the mean proportion of women who participated in the trials was 38.8% (95% confidence interval [CI] = 34.5-43.4; I 2 = 82.4, 95% CI = 81.0-83.6). Women's participation rates were higher in studies sampling more HF patients with hypertension (B = 1.01, SE = 0.45, P = .046) but fewer HF patients prescribed beta blockers (B = -1.10, SE = 0.33, P = .006), F (2,12) = 6.27, P = 0.014, adjusted R 2 = 61%. SMIs may offer women a complementary or integrative approach to standard treatment to help manage the psychological distress associated with HF. Future research should explore the potential benefits of offering stress management approaches to women as part of comprehensive HF care.

The thermal stratification is generic to un-isolable piping system in pressurized water reactor (PWR), which is not considered in original design. This effect can finally threaten the integrity of the piping system. The pressurizer surge line is affected by thermal stratification during reactor heat up and shutdown processes particularly. It’s important to investigate and mitigate thermal stratification in the surge line to meet safety requirements. In this paper, the thermal hydraulic analysis and the mechanical analysis using numerical simulation method were conducted to evaluate the impact of thermal stratification in the surge line during reactor heat up processes. The results give the three-dimensional temperature distribution and stress status of the surge line. It indicates that thermal stratification can cause stress concentration in the displacement restricts. The mitigation of thermal stratification was also studied. The numerical simulation of pressurizer surge line can put forward thermal stratification analysis.Copyright © 2010 by ASME

12 illus. 4 tables 3 graph.; International audience; In this paper a numerical simulation of a spray dryer using the computational fluid dynamics (CFD) code Fluent is described. This simulation is based on a discrete droplet model and solve the partial differential equations of momentum, heat and mass conservation for both gas and dispersed phase. The model is used to simulate the behaviour of a pilot scale spray dryer operated with two drying media : superheated steam and air. Considering that there is no risk of powder ignition in superheated steam, we chose a rather high inlet temperature (973K). For the simulation, drop size spectrum is represented by 6 discrete diameters, fitting to an experimental droplets size distribution and all droplets are injected at the same velocity, equal to the calculated velocity of the liquid sheet at the nozzle orifice. It is showed that the model can evaluate the most important features of a spray dryer : temperature distribution inside the chamber, velocity of gas, droplets trajectories as well as deposits on the walls. The model predicts a fast down flowing core jet surrounded by a large recirculation zone. Adding to the inherent interest in using superheated steam as a drying medium, the model predicts attractive behaviour for spray drying with superheated steam.

Starvation is a vivid word to describe the operation condition of a fuel cell in sub-stoichiometric reactants feeding. In starvation, a fuel cell could not present its best performance; moreover, there might also be safety issue because of cell reversal. In this paper, current density distributions of proton exchange membrane fuel cell (PEMFC) in hydrogen and air starvation were studied with a segmented single fuel cell. Experimental results show that the polarization curves of the overall cell are different for anode and cathode starvation. And the current density distribution results show that for anode starvation, current density of the starved region drops sharply to zero, while for cathode starvation, there is no zero current density region observed. Numerical simulations give similar results.

A typical diesel engine port is of complicated geometry . This paper addresses the experimental studies of intake port of a four cylinder diesel engine for different vacuum pressures and valve lift positions. In this study the cylinder head is experimented through a paddle wheel flow setup which gives the flow coefficient and swirl number as output. The main scope of the work is to understand the flow behaviour through the intake port and finally to determine mean flow coefficient and mean swirl number for different valve lift ratios L/D, where L is valve lift and D is bore diameter. This paper also addresses the geometry acquisition and grid generation for three dimensional Computational Fluid Analysis for flow filed computation and obtain a calibrated CFD code for future design once the code is validated with experimental results

Typical caterpillar tractors, applied to wood gathering in forests, are powered by internal combustion (IC) engines, which are sized to meet the full drivetrain load. However, the maximum power is required only in a part of the total operation time during work cycles of logging tractors. For this reason the hybrid electric propulsion system, installed instead of IC engine-hydrostatic transmission system, may considerably improve vehicle performance indices such as fuel consumption, pollutant emission and noise level. In this paper we present a series hybrid electric powertrain configuration for a small (2100 kg of mass) crawler tractor used for logging in forests. The drivetrain is composed of a thermal engine, an electric generator, a group of lead-acid batteries and electric drive motors with controllers. To calculate energy balance of the designed vehicle a special "forest cycle" was elaborated and discussed in the paper. The cycle was created on the basis of experimental data, measured in the actual tractor work. Since average power required during the "forest cycle" is much lower than the maximum one, the hybrid electric system needs a smaller IC engine than one in the conventional vehicle. This engine, coupled with electric generator, works in operation conditions yielding better fuel economy. The electric drive motors are fed both by the generator and the batteries in the "full load" cycle phase. The batteries are recharged during vehicle down-hill moving and standing phases.

The paper is a historical summary of American contributions to hydraulic measurement of streamflow for the period 1776-1976. The development and interrelation of conduit flow measuring devices together with open channel measuring devices is included in this update of previous historical summaries. The narrative style and historical sequence is a useful complement to the more specific "Bibliography on Discharge Measurement Techniques." /ASCE/

This paper demonstrates a novel digital radio distribution system able to transmit not only over optical fibres and coaxial cables but also over twisted pair cables. The digitised RF signal is compressed for maximum transmission efficiency in a way that allows for integral self-learning algorithms to be introduced for multi-service applications. © 2013 IEEE.

In order to meet the demand of integrated data transmission for electronic systems of aerocraft and ground vehicles, the FC-AE-1553 protocol and IP protocol can be supported on the fiber channel network. The FC-AE-1553 protocol supports periodic service and strong timing service and uses the fixed bandwidth and preemptive bandwidth allocation. IP protocol supports burst service and uses dynamic bandwidth allocation mechanism based on weight ratio. In this paper, a multi service FC network simulation platform is constructed, and the scheduling mechanism is analyzed by combining theoretical analysis with simulation. The results show that compared with the traditional command response scheduling mechanism, the proposed strategy can increase the average throughput of the network by more than 10 times, the network throughput can be increased from 2.8Gbps to 46Gbps, and the average delay of IP packets can be reduced by 1 order of magnitude.

In this paper we investigate the effects of superconducting shielded core reactor (SSCR) on the operation of induction generators. Large number of induction generators used in wind power plants generally increase the short circuit current level of the system. The reason is that they provide parallel reduced-impedance paths for the fault currents. Taking advantage of SSCR in wind power plants allows for using these generating units in large numbers with no concerns about the system fault current increments. The study is performed on a test system using the conventional model of an induction generator and a new effective model for SSCR based on its shielding behavior. Mathematical equations are discussed in detail and the associated SIMULINK model is presented. Computer simulation examines the effectiveness of SSCR in reducing the fault current level as well as provision for transient stability without affecting the normal operation of the system.

In the field of driverless cars, safety is the main concern. The safety systems for these cars are mainly dependent on the inputs of cameras and sensors like Light Detection and Ranging (LIDARs). Lidar is an essential component in driverless cars which creates 3D map of the surrounding and assists the car for driving. Lidar based safety systems are effective but are very expensive as the lidars are costly. Hence, there is a need to design a system which can assist the car effectively on the road, without using the lidar. This paper presents a proposed design of accident avoidance system for driverless cars, which uses computer vision techniques and works on the input of single video camera. It analyzes the video frames and shows accident warnings while on turn or lane change. The system is cost effective and can work with IoT devices having low computational power. To verify the performance of the system, we have performed experiments on various scenarios including cars at different positions moving with different speed and we obtained satisfactory results.

In this paper, a non-contact optical system, a low-coherence interferometer (LCI), is introduced for the purpose of measuring the surface roughness of turbine blades. The designed system not only possesses a high vertical resolution and is able to acquire the roughness topography, but also it has a large vertical scanning range compared to other commonly used optical systems. The latter characteristic allows us to measure turbine blades surfaces with large curvature without collisions between the lens and the measurement object. After obtaining the surface topography, wavelet analysis is applied to decompose the original surface into multiple bandwidths to conduct a multiscale analysis. The results show that the developed LCI system proofs a good performance not only in obtaining the surface topography in the roughness scale but also in being able to measure surfaces of objects that possess a complex geometry in a large vertical range. Furthermore, the applied biorthogonal wavelet in this study has performed good amplitude and phase properties in extracting the roughness microstructures from the whole surface. Finally, the traditional roughness parameters, such as the mean surface roughness S a and the Root Mean Square (RMS) roughness S q , are evaluated in each decomposed subband and their correlations with the scale of each subband are analyzed.

A cooperative drive vector in the paper is proposed on the basis of the three evaluation factors of the target detection, which are area inertia, number inertia and neighborhood similarity. The cooperative detection is performed through the auto-evaluation of target detection results about the cooperative drive vector. The experiments show that the method of automatic evaluation of detection result is effective.

The forces transmitted through any cross-section of a machine member such as a robot arm can be reduced to a single force and torque acting on any chosen point of the cross-section. The force and torque can be measured by a sensor that replaces the cross-section. A special feature of the sensor discussed here is that it is two dimensional, i.e. that it can be manufactured as a thin, planar sandwich. This makes for simplicity, compactness, low cost and ruggedness. In this paper we derive the constraints on design that must be met in order for the output to be unbiased with respect to force and torque directions. We show that feasible planar designs exist.

In order to have an immediate impact on building energy-related emissions, existing buildings need to be addressed. To inform policy and technical decisions, detailed mathematical models are required which can explore numerous building retrofit solutions and their energy and emissions performance . This paper describes the adaptation of a hybrid statistical and engineering-based model for residential building stock in Canada to analyze community-scale energy retrofits . The modelling domain includes both envelope and mechanical retrofits, as well as district renewable energy systems. This model is then applied to a case study of converting a community of fifty 1980’s vintage single-detached homes to achieve net-zero energy. The case study demonstrated that deep envelope retrofits and fuel switching from natural gas to electric heat pump systems reduce community energy demand by 69%. Saturating available roof area with photovoltaics was able to achieve net-zero balance. By considering net-zero at the community-scale, individual buildings that did not achieve net-zero were offset by net-exporting neighbours. Annual community emissions of the retrofit reduced emissions by 95%. The analysis also highlights the significant impact on electrical infrastructure due to solar generation and energy demand mismatch.