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This paper presents a comprehensive review on solar tracking systems and their potentials in solar energy applications. The paper overviews the design parameters, construction, types and drive system techniques covering different usage application. There are two main solar tracking systems types that depending on their movement degrees of freedoms are single axis solar tracking system and dual axis solar tracking system, which are addressed in the recent studies. The solar tracker drive systems encompassed five categories based on the tracking technologies, namely, active tracking, passive tracking, semi-passive tracking, manual tracking, and chronological tracking. The paper described the various designs and components of the tracking systems. There are 42.57% of the studies discussed and presented single axis tracking systems while 41.58% of these studies to the dual axes tracking systems. In the recent research studies, the most common solar tracker drive type was active tracker by 76.42% usage in applications while in the second most impact type is the chronological solar tracker by 7.55%. Furthermore, in the solar tracking techniques, Azimuth and altitude tracking achieved 16.67% in usage, Horizontal tracking by 16.67%, Azimuth tracking by 10%, and polar tracking by 4.44%. [ABSTRACT FROM AUTHOR]

The active and healthy ageing paradigm is gaining momentum as technology is turning the futuristic scenarios envisioning smart homes into reality. An ecosystem of services and devices devoted to risk prevention, prediction and early intervention will support older people in extending the time they live independently. Despite the similarities found between the field of Active and Healthy Ageing and the Internet of Things, there are two main aspects that justify a dissociated analysis. First, most of the targeted users can be somehow considered vulnerable, either because of their lack of technological literacy or because they may even suffer some kind of cognitive impairments (although this might be in a very early stage). Second, such ecosystems are thought to be deployed in one of the most private spheres of a human being, as it is the home. For this reason, special protection should be granted to the devices and services deployed in this domain. However, this contrast with the current state of the cybersecurity for Active and Healthy Ageing. There are no specific studies, standards or guidelines available to assist manufacturers and developers in their work. This does not apply to ethical or general security concerns that have been adequately addressed. In this sense, it is necessary to complement existing ethical and data privacy and security guidelines, with other aspects related to the security of IT systems for this particular application field. This paper aims to fill this gap by presenting a general analysis of the main issues that require special attention from a cybersecurity perspective. [ABSTRACT FROM AUTHOR]

Abstract: This paper analyzes two important problems of online thematic map cartography facing, namely which technique solution is appropriate and how to simplify the cartography process. Firstly, contrasts some popular technique solutions of thematic map, and points out the bottlenecks and inconveniences of thematic map cartography process nowadays, then brings out active online thematic map cartography based on the technique solution of RIA (Rich Internet Applications). In addition, this paper gives out RIA-based implementation framework of active online thematic maps mapping, which is contrasted with RIA-based implementation framework of general online thematic maps mapping, and main methods of building knowledge of active cartography of thematic map. [Copyright &y& Elsevier]

Electrokinetic driven flow can be used as an active technique to improve mixing in various devices. This technique is employed to mix fluid samples rapidly and efficiently in different geometries. There are numerous numerical and experimental studies on this subject in the literature. This paper is review of the studies performed on electrokinetic mixing techniques including electroosmosis, electrophoresis, and dielectrophoresis to discuss about capabilities, shortcomings, and various industrial and engineering applications of this method. Based on this survey, conclusions and suggestions for future works are provided. [ABSTRACT FROM AUTHOR]

Recent studies at the Center for Infrastructure Protection and Physical Security (CIPPS) have focused on both active and passive protection, the definition and characterization of combined blast and fragment loads on structural elements, the influence of Ultra High Performance Concrete (UHPC) on the behavior of structural elements, and evaluating analysis approaches for progressive collapse assessment. Those studies have highlighted important issues that have not been sufficiently addressed previously, and this paper is aimed at describing the observations from the CIPPS studies that could be used to treat such difficult issues. [ABSTRACT FROM AUTHOR]

This paper presents the development of the CYBERLEGs Alpha-Prototype prosthesis, a new transfemoral prosthesis incorporating a new variable stiffness ankle actuator based on the MACCEPA architecture, a passive knee with two locking mechanisms, and an energy transfer mechanism that harvests negative work from the knee and delivers it to the ankle to assist pushoff. The CYBERLEGs Alpha-Prosthesis is part of the CYBERLEGs FP7-ICT project, which combines a prosthesis system to replace a lost limb in parallel with an exoskeleton to assist the sound leg, and sensory array to control both systems. The prosthesis attempts to produce a natural level ground walking gait that approximates the joint torques and kinematics of a non-amputee while maintaining compliant joints, which has the potential to decrease impulsive losses, and ultimately reduce the end user energy consumption. This first prototype consists of a passive knee and an active ankle which are energetically coupled to reduce the total power consumption of the device. Here we present simulations of the actuation system of the ankle and the passive behavior of the knee module with and without the energy transfer effects, the mechanical design of the prosthesis, and empirical results from testing of the physical device with amputee subjects. [ABSTRACT FROM AUTHOR]

It is well known that there is a need to develop technologies to achieve thermal comfort in buildings lowering the cooling and heating demand. Research has shown that thermal energy storage (TES) is a way to do so, but also other purposes can be pursued when using TES in buildings, such as peak shaving or increase of energy efficiency in HVAC systems. This paper reviews TES in buildings using sensible, latent heat and thermochemical energy storage. Sustainable heating and cooling with TES in buildings can be achieved through passive systems in building envelopes, Phase Change Materials (PCM) in active systems, sorption systems, and seasonal storage. [ABSTRACT FROM AUTHOR]

In tactile micro coordinate metrology, miniature probing systems are required to allow geometric measurements of miniature, delicate, high precision components. These probing systems typically comprise of a small stylus of only a few mm in length, with a spherical tip of around 100 μm in diameter or less. The stylus is mounted to a flexible suspension structure which is designed to deflect during measurement, and defines the stiffness of the probing system. Stiffness is of critical importance for optimum measurement performance, and selection of the correct stiffness involves a difficult trade-off. Stiff probes are needed to overcome surface attraction forces which are significant for the small stylus tips, while flexible probes are needed for contact with delicate parts to reduce contact stress and ensure no damage is caused. To eliminate the need for compromise a novel micro tactile probing system with active stiffness control using a novel suspension structure has been designed. This paper presents the initial fabrication and the test of the suspension structure. The stiffness of the structure is assessed by measuring the modal frequencies of the suspension structure that correspond to vertical and lateral probe motion. Using this method results show it is possible to reduce the vertical and torsional frequency by 69% and 33%, respectively. Using finite element analysis it is shown that this equates to vertical and lateral stiffness reductions to 12% and 46% of their initial value, respectively. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a new, noncontact magnetic actuator instrumented with fibre optic displacement sensors. The actuator is composed of four identical electromagnetic units which are linearized with a novel design strategy. The magnetic force can be delivered in two radial directions for active damping of lateral modes of the boring bar. The actuator is manufactured and mounted on a CNC lathe. The bending mode of the boring bar is actively damped, and the dynamic stiffness of the system was increased significantly, resulting in chatter-free higher depth of cuts. The actuator has been experimentally tested in boring operations. [Copyright &y& Elsevier]

Photovoltaic (PV) systems are increasingly assuming a significant share in the power generation capacity in many countries, and their massive integration with existing power grids has resulted in critical concerns for the distribution system operators. Most of these critical concerns arise due to abnormalities at the grid side (undervoltage and short-circuit events), and as a consequence of failing islanding detection (ID). Generally, an ID mechanism operating with the PV system in a grid connected environment, should be capable of disconnecting the PV from the grid in case of grid abnormalities by obeying to specific grid codes. For any condition if the ID mechanism fails to adhere to this specific requirement, the grid abnormality will disperse a large part of generation unit, and also damages the equipment connected in the grid. In light of the above concerns, numerous ID techniques (IDTs) have been introduced in the literature. These techniques are categorized into five classes, based on the input parameters, point of implementation in the system, and the methodology adapted to develop them. This paper is focussed on surveying the various IDTs developed in the literature to identify their advantages and disadvantages. A machine-learning strategy based on signal processing is proposed to overcome the drawbacks of existing IDTs in the current technical literature. The signal processing part is implemented with wavelet transform, and the support vector data descriptor (SVDD) is trained as a machine learning classifier. To assess the operation of the proposed approach, experimental analysis is carried out on a 4 k W p grid-connected PV system in different islanding conditions. The results identified 97.2 % training accuracy, 100 % testing accuracy, and an average detection time of less than 25 m s for all the testing conditions. • A comprehensive review towards islanding detection (ID) techniques is presented. • Prospects and challenges of traditional ID techniques are highlighted. • An accurate and fast ID mechanism is proposed. • Wavelet transform and machine learning are used to develop the islanding classifier. • Developed ID mechanism has higher accuracy than conventional techniques. [ABSTRACT FROM AUTHOR]

Abstract: A symmetrizer for a symmetric Runge–Kutta method is designed to preserve the asymptotic error expansion in even powers of the stepsize and to provide damping for stiff initial value problems. In this paper we study symmetrizers for the Gauss methods with two and three stages and compare the implementation in passive and active modes. In particular, we perform a detailed analysis of the Prothero–Robinson problem which provides insight into the behaviour of symmetrizers in suppressing order reduction experienced by the symmetric methods. We present numerical results on the effects of passive and active symmetrization for some stiff linear and nonlinear problems. These effects have important implications for the development of extrapolation methods based on higher order symmetric methods for the numerical solution of stiff problems. Our results show that symmetrization in both modes improves accuracy and efficiency, and can restore the classical order of the Gauss methods for stiff linear problems. We compare the two modes of symmetrization for constant stepsize and present preliminary results in a variable stepsize setting. [Copyright &y& Elsevier]

Abstract: In this paper, we demonstrate active, sheathless density-based particle separation using standing surface acoustic waves. Density-based separation is critical for many biological applications, such as white blood cell classification, stem cell isolation, fetal cell collection from maternal blood, and specific bacterium sorting. Current gold standard separation techniques are only capable of separation based on particle size; hence, separation cannot be achieved for same-size particles with different densities. Here, the separation is accomplished with an acoustic force field (active technique) without using sheath flow. We demonstrate the separation of two 10μm diameter, different-density particle streams (polystyrene: 1.05g/cm3, melamine: 1.71g/cm3) with 98.8% separation efficiency. [Copyright &y& Elsevier]

Abstract: This paper presents the results of a numerical and experimental investigation into the use of a small, rapidly actuated, actively controlled trailing-edge flap (4% chord) to alleviate the unsteady loading experienced by wind turbine blades due to atmospheric turbulence and the atmospheric boundary layer. The computational investigation demonstrated that the rejection of realistic flow disturbances should be feasible with the use of load measurements on the blade and the feedback control of a small flap. The experimental prototype subsequently successfully rejected intentionally introduced flow disturbances from the vortex street of a square block located upstream of a sting-mounted, strain-gauged wing fitted with flap. This application of control provided a very significant reduction in the unsteady loading experienced (∼81% of C LRMS ). The findings show the potential of this method of load control for the rejection of unsteady aerodynamic loading by the sole use of load measurements from the wing for simple feedback control (PID/LQG). [Copyright &y& Elsevier]

Abstract: In this paper, design and fabrication of a micro direct methanol fuel cell based on stainless steel in two kind of active and passive with cross strip and parallel flow field are presented. Dropping pressure, velocity and heat transfer of the cell is simulated by a 3D modeling in fluent software. An optimum operating condition of the cell is obtained by the mass flow and temperature limitation. The cell was tested in different temperatures and mass flow rate and the cell performance is investigated in different condition. Maximum power density of the cell in active condition and at 60°C was 170mW/cm2 and in passive condition was 85mW/cm2. A μDMFC with different flow field is investigated. Cross strip flow field has shown better performance and the effect of cell orientation on performance is also investigated. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a numerical method is proposed for determining complex vibrations modes of sandwich structures with piezoelectric and viscoelastic layers. Based on homotopy and asymptotic numerical techniques, this method leads to the damping properties calculation (loss factor and natural frequency per mode) of the hybrid sandwich structure. The numerical results of the loss factor and natural frequency are compared to those obtained from analytical beam model and from numerical studies the modal strain energy method. [Copyright &y& Elsevier]

Abstract: This work is about solving the global localization issue for mobile robots, operating in large and cooperative environments. It tackles the problem of estimating the pose of a robot, or team of robots in a map reference frame, given the map, the real-time data from the robot onboard sensors, and the real-time data coming from other robots or sensors in the environment. After a first step of position hypotheses generation, an efficient probabilistic active strategy selects an action, for a single lost robot case, or two joint actions when two lost robots are in a line of sight, so that the hypotheses set is best disambiguated. The action set is adapted to the multi-hypothesis situation, and action evaluation takes into account remote observations available in robot network systems. This paper presents the theoretical formulation for both non-cooperative, and cooperative cases. An implementation of the proposed strategy is discussed, and simulation results presented. [Copyright &y& Elsevier]

Abstract: Natural ventilation has gained prominence in recent times as a bespoke method of ventilating buildings. The two fundamental principles of natural ventilation are stack effect and wind driven ventilation. This paper reviews miscellaneous wind driven ventilation designs with respect to traditional means such as wind towers and more modern techniques including turbine ventilators and wind catchers. A distinction is made between specific types of wind driven ventilation techniques depending on their operation and mode of engagement with the wind. For example, a static wind catcher is classified as passive; a rotating wind cowl as a directed passive technique and a rotating turbine ventilator is classified as outright active due to its constant rotation with the wind. A table summarising the review is presented at the end with corresponding references. [Copyright &y& Elsevier]

Abstract: In this paper, a self-organizing migrating genetic algorithm for constrained optimization, called C-SOMGA is presented. This algorithm is based on the features of genetic algorithm (GA) and self-organizing migrating algorithm (SOMA). The aim of this work is to use a penalty free constraint handling selection with our earlier developed algorithm SOMGA (self-organizing migrating genetic algorithm) for unconstrained optimization. C-SOMGA is not only easy to implement but can also provide feasible and better solutions in less number of function evaluations. To evaluate the robustness of the proposed algorithm, its performance is reported on a set of ten constrained test problems taken from literature. To validate our claims, it is compared with C-GA (constrained GA), C-SOMA (constrained SOMA) and previously quoted results for these problems. [Copyright &y& Elsevier]

Abstract: In this paper, the performance of active constrained layer damping (ACLD) treatment for active structural–acoustic control of a vibrating thin laminated cylindrical panel has been investigated. The constraining layer of the ACLD treatment has been considered to be made of piezoelectric fiber-reinforced composite (PFRC) material. A finite element model has been developed for the laminated panels integrated with the patches of ACLD treatment to describe the coupled structural–acoustic behavior of the panels enclosing an acoustic cavity. Both velocity and pressure rate feedback controls have been implemented to activate the patches. Symmetric and antisymmetric cross-ply and antisymmetric angle-ply panels have been considered for evaluating the numerical results. Emphasis has also been placed on investigating the effect of the piezoelectric fiber orientation in the PFRC layer and the shallowness angle of the cylindrical panels on the performance of the patches. [Copyright &y& Elsevier]

Abstract: In this paper, the year round thermal performance evaluation of active and passive solar water heating systems for rural/urban area have been studied. Two types experiments are the normalized draw-off temperature profile and the normalized draw-off mixing profile conducted in the months of April 2003–March 2004. Effect of morning, mid-afternoon, evening draw-off and effect of water mixing in the morning and evening are also studied during the experiments. Thermal efficiency for the system and collection efficiency for the collectors were calculated during the experiments. The values of F R ·(τα) of the collectors used in active and passive water heating systems were found 0.69 and 0.61 respectively. Ethylene glycol has a 50/50 glycol-to-water ratio used as a heat transfer fluid (HTF) in the systems due to the cold climate in South Korea. [Copyright &y& Elsevier]

Abstract: This paper deals with the analysis of active constrained layer damping (ACLD) of laminated thin composite shells using piezoelectric fiber reinforced composite (PFRC) materials. The constraining layer of the ACLD treatment is considered to be made of the PFRC materials. A finite element model of the smart composite shells integrated with the patches of such ACLD treatment has been developed to demonstrate the performance of these patches on enhancing the damping characteristics of thin symmetric and antisymmetric cross-ply and anti-symmetric angle ply laminated composite shells. The effect of variation of piezoelectric fiber orientation in the constraining PFRC layer on the control authority of the patches has also been investigated. [Copyright &y& Elsevier]

Radio galaxies host relativistic jets oriented away from our line of sight, making them challenging targets for Very High Energy (VHE, E > 100 GeV) γ -ray detectors. Indeed, out of ∼ 100 extragalactic sources detected at E > 100 GeV, only six are radio galaxies, while the great majority are blazars hosting aligned jets. The new Cherenkov Telescope Array (CTA) will provide order-of-magnitude improvements in sensitivity and spectral resolution with respect to the present generation of ground-based γ -ray observatories, opening new frontiers for high-energy studies of radio galaxies. In a previous paper, we studied the detection prospects of misaligned jets with the CTA for a sample of sources from the Third Fermi -LAT catalog (3FGL). In this work, we complement this study taking advantage of the expanded sample from the Fourth Fermi -LAT catalog (4FGL), which includes roughly double the number of sources. We simulate CTA observations of 41 γ -ray radio galaxies, extrapolating their Fermi -LAT spectrum into the TeV energy range assuming different spectral shapes. We predict that the CTA will detect eleven new TeV radio galaxies with an observational campaign of 50 hours per source, under the realistic assumption of a spectral cutoff at 0.5 TeV. This would increase the sample of VHE radio galaxies by a factor of three, and result in the first detection of FR II radio galaxies at these energies. By simulating CTA observations with 5 h exposure, we predict that two Fermi -LAT radio galaxies should already be well within reach of current TeV observatories. Finally we have investigated the prospects for a CTA detection of extended VHE emission from the lobe-dominated FR I Fornax A, and predict that such a detection will be possible for integration times ≳ 50 h. We conclude that, in line with our previous findings, the CTA will significantly impact our understanding of misaligned jets at TeV energies, allowing us to perform population studies, as well as a comparison between the two main radio galaxy subclasses for the first time in this energy band. [ABSTRACT FROM AUTHOR]

This paper investigates three different configurations of a hybrid battery thermal management system (BTMS) using phase change material (PCM) as passive and air coolant as active cooling system. The PCM surrounded the battery cell is encapsulated in three different vessel cross-sections as circular, rectangular, and hexagonal with equal volumes. Each of these BTMS consists of 12 Sony 18650 batteries with the same pack holder. The thermal management of the battery pack is examined in the course of different charging and discharging rates. Results reveal that the thermal performance of both hexagonal and circular PCM vessels show generally the same behavior. Utilization the latent heat as the passive coolant in the battery thermal management is the strong point, which results show that the circular PCM configuration is the best one. However, in the high rate of charging or discharging condition, the uniform air channel around the rectangular shape makes a more efficient cooling compared to the other arrangements. • Investigate on the hybrid active-passive battery thermal management system (BTMS) is the main objective. • Phase change material (PCM) as passive and air coolant as an active cooling system are considered. • A transient numerical study conducted on the three different PCM encapsulation shape. • Uniform shape of PCM encapsulation (circular shape) is the thermal efficient in the passive cooling. • Uniform air channel, rectangular shape of PCM encapsulation is thermal efficient in the active cooling. [ABSTRACT FROM AUTHOR]

Abstract: Proximity lithography using thin membrane window structures to carry masking patterns during radiation exposure steps is reaching levels of such high precision that the process can benefit from active elastic control of membrane deformations. This paper discusses two methods of actively controlling membrane mask deformation. The first is the mitigation of unwanted out-of-plane aeroelastic effects caused by rapidly stepping between wafer exposure fields while maintaining a sub 100μm gap. The second is an in-plane thermoelastic active deformation to improve overlay accuracy. [Copyright &y& Elsevier]