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• Proposed architectures of the roof-top solar PV system, and the cluster of four PVs on different buildings based microgrid. • The centralized controller is used in the proposed microgrid system. The control techniques of the bidirectional VSCs, used of interfacing the PV, BESS, load, and microgrid, have been developed for managing power balance in the proposed system. • Developed control technique of the bidirectional single-phase VSC, using feed-back and feed-forward control signals, is suggested into rotating dq SRF, with dual controllers for controlling ac current/voltage. • Control technique of the BDC for BESS are proposed using two voltage controllers and one current controller, for controlling the charging and discharging operation of the BESS to fulfil the power mismatch in its own building as well as in other building(s) integrated to the microgrid. •. Power control algorithms are also proposed for balancing the power in the roof-top PV system as well as cluster of four roof-top PVs. This paper presents the control techniques for the operation of roof-top solar photovoltaics based single-phase ac microgrid in islanded mode. The proposed microgrid consists of four roof-top photovoltaics on various buildings, battery energy storage system in each building, and loads. In each building, the roof-top photovoltaic system is connected to the single-phase ac loads and proposed single-phase ac microgrid through the two-stage converter, which consists of dc-dc boost converter and bidirectional single-phase voltage source converter. A bidirectional dc-dc converter is used to connect the battery energy storage system to the photovoltaic system. The control technique of the bidirectional single-phase voltage source converter, using the feed-forward and feed-back control signals, has been suggested into a rotating d-q synchronous reference frame, with the dual controllers, for controlling the power mismatch and rated sinusoidal ac voltage of the microgrid. The control technique of the bidirectional dc-dc converter, used for the battery energy storage system, is implemented with two voltage controllers and one current controller for managing of the power mismatch in the proposed microgrid system. In this work, the power control algorithms have also been developed, which are aimed to manage the power balance in the single roof-top PV based building as well as in the proposed microgrid, under islanded mode, for various operating scenarios including fault condition. [ABSTRACT FROM AUTHOR]

Global routing performance and saving energy are critical for Internet applications. Internet service providers use the internal Border Gateway Protocol for the distribution of external routes within the autonomous system. The balance between the trade-off relationship of energy efficiency and quality-of-service is necessary for autonomous systems in green networking. Past studies have shown that energy saving schemes exacerbate quality-of-service. However, the optimum use of resources balances the trade-off between energy efficiency and quality-of-service. Therefore, we propose a Green BGP model that balances the trade-off between energy efficiency and quality-of-service by optimizing the internal Border Gateway Protocol path selection policy. Border Gateway Protocol routers select a path considering the quality-of-service attributes and energy efficiency of the path within the autonomous system. The proposed model is compared with related techniques, and the results confirm the advantages of the Green BGP model that improves energy efficiency and maintains quality-of-service. [ABSTRACT FROM AUTHOR]

The present work aims to examine the entropy heat generation analysis for unsteady MHD couple stress fluid flow over a uniformly heated vertical flat plate. The mathematical model of this problem is given by highly time reliant non-linear coupled equations and resolved by an efficient unconditionally stable implicit scheme. The time histories of average values of momentum and heat transport coefficients, entropy and Bejan lines, as well as the steady-state flow variables, discussed for several values of non-dimensional parameters arising in the flow equations. Results specify that time required to attain the time independent flow with respect to the flow field variables get amplified with the augmented values of couple stress parameter. The outcomes also indicate that entropy generation parameter upsurges with rising values of group parameter and Grashof number while the reverse trend is observed for couple stress parameter and magnetic parameter. [ABSTRACT FROM AUTHOR]

Concurrent Multipath Transfer (CMT) is a transport layer protocol which provides concurrent data transfer over the multiple paths. CMT improves the available bandwidth utilization, fault tolerance, robustness and reliability of the network. However, in multipath data transfer, destination receives out-of-order data chunk due to dissimilar delay and bandwidth of each path. It causes the serious problem of receiver buffer blocking, unwanted congestion window ( cwnd ) reduction and unnecessary retransmission, which significantly degrades the performance of CMT. Thus, this paper proposes an adaptive data chunk scheduling for CMT (A-CMT). The proposed method uses path delay and bandwidth as a factor of data chunk scheduling to adapt path conditions. The simulation results show that proposed method achieves better performance in terms of throughput; file transfer time and congestion window growth. The proposed method improves average throughput up to 13%. [ABSTRACT FROM AUTHOR]

The present study numerically explores the thermally radiative incompressible flow of hybrid nanofluid due to the stretchable rotational disk with the consideration of externally applied magnetic field and examines the underlying transport of heat both qualitatively as well as quantitatively. Pertaining to this study, the traditional von Karman approach is applied to convert partial derivative form of governing nonlinear transport equations into ordinary derivative form and is then evaluated by using an efficient boundary value problem (BVP4c) solver. The simulated results of flow-field variables such as velocity, temperature, friction-factor coefficients for various physical factors have been discussed both apparently in graphical form as well as numerically in the tabular form. In addition, we aptly discussed the influence of entropy heat generation and Bejan number obtained for different physical parametric values on the underlying thermohydrodynamics. The results indicate that the radial and tangential velocities across the rotating disk decrease for greater values the magnetic parameter (M) and slip factor (γ). As shown in this study, the effect of augmented fractional volume (ϕ 2) leads to a decrease of the fluid velocity owing to the accumulation of the nanoparticles in the working fluid. An increasing the value of magnetic and radiation parameters results in thickening the thermal boundary layer, which in turn induce an enhancement in the fluid temperature. Finally, it is seen that for an intense effect of the thermal radiation and viscous dissipation, the thermodynamic irreversibility in the present system becomes higher. We believe that the developed modelling frame-work has the potential to effectively analyze the underlying fluid flow and heat transfer in turbomachinery, high-end heat transfer process applications. [Display omitted] • Effect of Magnetic field and radiation on the Hybrid-nanofluid flow in a rotating disk. • Increase in radiation and magnetic parameters invite higher thermodynamic Irreversibility. • The von Karman approach is employed in the solution method. [ABSTRACT FROM AUTHOR]

Abstract: In the internet environment, the Diversity-path-aware Border Gateway Protocol (D-BGP) increases path diversity by advertising multiple paths. In case of a route failure, D-BGP, selects the most disjoint alternative path, but does not consider its quality moreover because update messages are propagated both for the best path and for alternate paths, D-BGP has messaging. To overcome these limitations, we propose a robust BGP protocol that increases fault tolerance and reduces update message overhead. After establishing shortest paths using D-BGP, our protocol selects an alternate path based on link availability of the link and bandwidth. It utilizes Path Exploration Damping (PED) to delay update messages of alternate paths with worst-case scenario. Simulation results justify that our proposed BGP is failure free and performs better than D-BGP. [Copyright &y& Elsevier]

Abstract: In the present work, we report the growth of wurtzite InN epilayers on GaN/Si (111) substrate by plasma-assisted molecular beam epitaxy (PAMBE). The growth parameters such as indium flux, substrate temperature and RF power affect the crystallographic and morphological properties of InN layers, which were evaluated using high resolution X-ray diffraction (HRXRD) analysis and atomic force microscopy (AFM). It is found that excess indium (In) concentrations and surface roughness were increased with increase in In flux and growth temperature. The intensity of HRXRD (0002) peak, corresponding to c-axis orientation has been increased and full width at half maxima (FWHM) has decreased with increase in RF power. It was found that highly c-axis oriented InN epilayers can be grown at 450°C growth temperature, 450W RF power and 1.30×10−7 mbar In beam equivalent pressure (BEP). The energy gap of InN layers grown by optimizing growth conditions was determined by photoluminescence and optical absorption measurement. [Copyright &y& Elsevier]

Abstract: This paper presents the effect of offset (i.e. inlet and outlet are in two different planes) on S-shaped diffuser of 90°/90°turn with rectangular inlet () and semicircular outlet (). A computer program based on finite volume technique, using standard turbulence model, has been adopted and modified to predict the flow. The obtained results from this research show reduced outlet pressure recovery accompanied with increase in non-uniformity at the exit due to offset. This paper also shows that increase in Reynolds number has marginal effect on the outlet pressure recovery for zero offset and 0.3125D cases and similar results have been found for other offset cases which have not been presented in the paper to avoid repeatability. The present S-duct geometry fulfills only pressure recovery requirement, and hence needed modification to improve the uniformity at the exit. [Copyright &y& Elsevier]

Efficient manipulation of micro biological cells has always been a very important task in healthcare sector for which a Micro Electro Mechanical System (MEMS) based impedance flow cytometry has been proven to be a promising technique. This technique utilise the advantage of dielectrophoresis (DEP) force which is generated by non-uniform electric field in a microfluidic channel using an appropriate external AC supply at certain frequency range. The DEP forces generated in micro-channel depend upon various biological and physical parameters of cell and suspending medium. Apart from that design parameters of microfluidic channel and dimension of electrodes used for generating DEP action also plays major role in micro cell/bead manipulation. This article give remarks on the operating parameters which affects the cell manipulation and interrogates the currently accepted various electrode orientations in microfluidic MEMS flow cytometer technologies for effective manipulation of micro entities like healthy human cells (T-lymphocytes, B- lymphocytes, Monocytes, Leukocytes erythrocytes and human kidney cells HEK293), animal cells (neuroblastoma N115 and sheep red blood cells), cancer cells (MCF-7, MDA-435 and CD34+), yeast cells (saccharomyces cerevisiae, listeria innocua and E. coli) and micro particles (polystyrene beads) based on their dielectric properties using DEP action. Article focuses on the key electrode orientations for generation of non-uniform electric field in microfluidic flow cytometer like tapered electrodes, trapezoidal electrode arrays, Interdigitated electrodes, curved microelectrode and 3D electrode orientations and give remarks on their advantages and limitations. The cell manipulation with current MEMS impedance flow cytometry orientations targeting possibilities of implementation of the lab-on-chip devices has been discussed. • Efficient biological cells/micro particle manipulation by impedance flow cytometry is discussed for healthcare applications. • Operating parameters affecting the cell manipulation in a microchannel of impedance flow cytometry has been described. • Electrode orientations with operating parameters like electric field & field frequency for cell manipulation is interrogated. [ABSTRACT FROM AUTHOR]

In the present research article, the transient radiative free convective hydromagnetic Casson fluid flow past a vertical cylinder with entropy heat generation is analysed numerically. The mathematical model of this problem is constituted by highly time-dependent non-linear coupled equations and they are resolved by an efficient unconditionally stable implicit scheme. The time histories of average values of momentum and heat transport coefficients, entropy generation and Bejan number, as well as the steady-state flow variables are discussed for several values of non-dimensional parameters arising in the flow equations. The results indicate that entropy generation parameter and Bejan number upsurges with rising values of Casson fluid parameter, viscous dissipation parameter, group parameter and Grashof number, whereas the reverse trend is observed for radiation and magnetic parameters. Also, it is viewed that the variation of entropy and Bejan lines occurs in the proximity of the hot cylindrical wall only. Finally, a comparison between the Casson and Newtonian fluid is made based on the obtained numerical results of the present study and this has important implications in industrial thermal materials processing operations. [ABSTRACT FROM AUTHOR]

• We developed a Delay-based Adaptive Congestion Control TCP variant (DACC). • DACC has an initialization method that obtains an optimal initial value for the congestion window. • It has a queueing-delay variation-based scheme that contemplates the contribution of all contention traffic flows. • It has improved performance in goodput, throughput, file transfer time, and fairness. Delay-based congestion control policies of the Transmission Control Protocol (TCP) mainly use the Round-Trip-Time (RTT) and bottleneck queue size to detect congestion. However, these policies identify congestion by only taking into account the contribution of their own data flow. Thus, the congestion identification in these policies fails to be completely accurate. Moreover, these policies experience many packet losses resulting in retransmissions, which can further reduce channel utilization. This article proposes a queuing delay variation-based adaptive congestion control TCP variant, called Delay-based Adaptive Congestion Control (DACC), that considers the presence of background flows. DACC quickly adapts to the current network conditions and adjusts the transmission rate accordingly. The simulation results exemplify the significance of DACC as it yields better outcomes in terms of goodput, Packet Loss Ratio (PLR), inter-protocol fairness, intra-protocol fairness, and fast file transfers. [Display omitted] [ABSTRACT FROM AUTHOR]

The mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) is a highly invasive and polyphagous pest of global incidence. The fundamental hypothesis of the present study was that the temperature variations due to global climate change may affect seriously the future distribution and abundance of P. solenopsis, which might further aggravate the crop yield losses. We employed a temperature-based phenology model of P. solenopsis in a geographic information system for mapping population growth potentials of P. solenopsis. The three risk indices viz., establishment risk index, generation index and activity index were computed using interpolated temperature data from worldclim database for current (2000) and future (2050) climatic conditions. The daily minimum and maximum temperature data from four selected weather stations in India were used for analysing within-year variation of pest population. A linear relationship was established between the activity indices and yield losses at various locations reported in literatures for predicting the future trend of yield loss due to climate change. The results revealed that, under current temperature conditions P. solenopsis can complete >4.0 generations per year on ~80% of the global cotton production areas. Economic losses are likely to occur in areas where at least 8.0 generations can develop in a year; under current climate ~40% areas fall under this category. The increased geographical suitability at higher latitudes in cotton production areas, additional 2.0 generations per year, and 4.0 fold increase of population abundance of P. solenopsis are expected in tropical and sub-tropical cotton areas of Brazil, South Africa, Pakistan and India due to predicted climate change. Analysis of within year population increase at various selected locations in India revealed that, P. solenopsis attained maximum potential population increase during the major cotton growing season (May-June to October-November). On the other hand, the innate ability of P. solenopsis population to increase reduced considerably during off season and cooler winter months. The increased pest activity of P. solenopsis due to climate change may intensify the losses in cotton yield, with forecasted losses in India to increase from existing losses of million US$ 1217.10 to future losses of million US$ 1764.85 by the year 2050. Here, we illustrate the possible impact of climate change on future P. solenopsis exacerbation based on temperature-driven population studies, which will help in undertaking agro-ecoregion specific management strategies. [ABSTRACT FROM AUTHOR]

Cu 1-x Fe x O (x = 0, 0.0156, 0.0234 and 0.0312) nanoparticles have been synthesized by using a simple sol-gel route. A pure monoclinic phase (space group c2/c) was observed from XRD studies. A Rietveld analysis of the XRD spectra using GSAS software helped evaluate the variations of lattice constant, lattice strain and bond length/angles. With Fe doping, while the indirect bandgap could be nominally tuned from ∼1.40 eV to ∼1.46 eV, the Fe -doping seems to improve carrier concentration, mobility, and lattice regularity than pure CuO. The photocatalytic degradation of toxic methylene blue (MB) dye could be enhanced from 0.91%/min for the pure CuO to 1.48%/min for 3.125%- Fe- doped CuO. This property has been correlated to the carrier properties of the materials. The UV and visible photoresponse of Cu 1-x Fe x O nanoparticles was investigated. A drastic reduction in both UV and visible light-sensitivity with Fe -doping was observed and correlated with carrier properties. [ABSTRACT FROM AUTHOR]

Gas sensors are extensively employed for monitoring and detection of hazardous gases and vapors. Many of them are produced on rigid substrates, but flexible and wearable gas sensors are needed for intriguing usage including the internet of things (IoT) and medical devices. The materials with the greatest potential for the fabrication of flexible and wearable gas sensing devices are two-dimensional (2D) semiconducting nanomaterials, which consist of graphene and its substitutes, transition metal dichalcogenides, and MXenes. These types of materials have good mechanical flexibility, high charge carrier mobility, a large area of surface, an abundance of defects and dangling bonds, and, in certain instances adequate transparency and ease of synthesis. In this review, we have addressed the different 2D nonmaterial properties for gas sensing in the context of fabrication of flexible/wearable gas sensors. We have discussed the sensing performance of flexible/wearable gas sensors in various forms such as pristine, composite and noble metal decorated. We believe that content of this review paper is greatly useful for the researchers working in the research area of fabrication of flexible/wearable gas sensors. [Display omitted] • Comprehensive review of 2D materials for gas sensing applications. • Discussing of flexible and wearable 2D gas sensors. • Explanation of gas sensing mechanism. [ABSTRACT FROM AUTHOR]

[Display omitted] Development of metal dichalcogenides based air and water stable opto-electronic devices is a bottleneck in their commercial implementation. Here we address this issue by the direct catalyst-free deposition of fluorographene (FG) protective layer over monolayer MoS 2 (MS), where such an atomic interface is found to be providing enormous photoresponse and chemical stability to the device. Electric field modulated (ionic liquid (IL) electrolyte based top-gated) photodetectors are developed with MS only and FG-MS heterostructure, where the MS photodetector has the responsivity of ~1.3 A/W (with V GS = 0 V while unstable with IL gating) while that of FG-MS is ~2000 A/W (with V GS = 0 V and ~8000 A/W with V GS = 1.5 V, and the detectivity ~1013). This giant photoresponse of the FG-MS is validated with the help of ultrafast transient absorption spectroscopy assisted charge carrier dynamics studies at different temperatures. The broad optical response (350–850 nm) of the FG-MS is found to be intact not only in IL based gating but also after exposing in water for a month or heat treated in air at 200 °C. Interfacing and capping with FG, developed via the direct growth method, are found to be ideal for realizing high shelf-life and good responsivity photodetectors and solar cells of several other monolayer TMDs too, while available for wafer-scale manufacture. [ABSTRACT FROM AUTHOR]

Abstract: Zinc–Tin-Oxide (ZTO) thin films were deposited on glass substrate with varying concentrations (ZnO:SnO2; 100:0, 90:10, 70:30 and 50:50wt.%) at room temperature by flash evaporation technique. These deposited ZTO films were annealed at 450°C in vacuum. These films were characterized to study the effect of annealing and addition of SnO2 concentration on the structural, chemical and electrical properties. The XRD analysis indicates that crystallization of the ZTO films strongly depends on the concentration of SnO2 and post annealing where annealed films showed polycrystalline nature. Atomic force microscopy (AFM) images manifest the surface morphology of these ZTO thin films. The XPS core level spectra of Zn(2p), O(1s) and Sn(3d) have been deconvoluted into their Gaussian component to evaluate the chemical changes, while valence band spectra reveal the electronic structures of these films. A small shift in Zn(2p) and Sn(3d) core level towards higher binding energy and O(1s) core level towards lower binding energy have been observed. The minimum electrical resistivity (ρ ≈3.69×10−2 Ω-cm), maximum carrier concentration (n ≈3.26×1019 cm−3) and Hall mobility (μ ≈5.2cm2 v−1 s−1) were obtained for as-prepared ZTO (50:50) film thereafter move towards lowest resistivity (ρ ≈1.12×10−3 Ω-cm), highest carrier concentration (n ≈2.96×1020 cm−3) and mobility (μ ≈18.8cm2 v−1 s−1) for annealed ZTO (50:50) thin film. [Copyright &y& Elsevier]

This paper reports the deposition and characterization of nanocrystalline carbon thin films by filtered cathodic jet carbon arc technique assisted with three different gaseous environments of helium, nitrogen and hydrogen. All the films are nanocrystalline in nature as observed from the high resolution transmission electron microscopic (HRTEM) measurements, which suggests that the nanocrystallites of size ∼10–50 nm are embedded though out the amorphous matrix. X-ray photoelectron spectroscopic studies suggest that the film deposited under the nitrogen gaseous environment has the highest sp 3 /sp 2 ratio accompanied with the highest hardness of ∼18.34 GPa observed from the nanoindentation technique. The film deposited under the helium gaseous environment has the highest ratio of the area under the Raman D peak to G peak ( A D / A G ) and the highest conductivity (∼2.23 S/cm) at room temperature, whereas, the film deposited under the hydrogen environment has the lowest conductivity value (2.27 × 10 −7 S/cm). The temperature dependent dc conduction behavior of all the nanocrystalline carbon thin films has been analyzed in the light of Mott’s variable range hopping (VRH) conduction mechanism and observed that all the films obey three dimension VRH conduction mechanism for the charge transport. [ABSTRACT FROM AUTHOR]

• Explored the linear and nonlinear optical interaction in the Bi2Se3 single-crystal cleaved flake. • Kramer's Kronig approach and DFT calculations confirm the prominent 2 eV OBT from the Ɛ1 and Ɛ2 simulations. • Concurrently, the TRUS measurements are done to explore the excited-state dynamics of the states populating due to the Moss-Burstein shifts. • With the same excitation, probing in the NIR region shows the occurrence of the Pauli blocking. • The low temperature study give a clear evidence of presence of second surface state and a broad absorbance of 1.2 eV can be easily seen through TRUS. [Display omitted] We report the optical response and temperature-dependent excited-state carrier dynamics in the flake of Bi 2 Se 3 , which is cleaved from its single crystal. The optical properties are explored using the visible-near infrared (VIS-NIR), infrared (IR), and photoluminescence (PL) spectroscopies. The VIS-NIR spectra are then used to find the Ɛ 1 and Ɛ 2 using Kramer's Koning relations, confirming OBT of 2 eV and 1.4 eV. The DFT (density functional theory) calculations are also carried out to confirm the experimental optical transitions (OBT). To probe these OBT in the bismuth selenide, we have studied the temperature, fluence, and excitation dependent ultrafast transient reflectance over a wide spectral range from 2.58–0.77 eV (VIS-NIR) with different excitation energies 3.02 eV, 2.61 eV, 1.9 eV, and 1.4 eV to explore several previously unseen transitions that do not appear in PL spectroscopy and room temperature carrier analysis. The temperature-dependent excited-state dynamics are investigated at 5–300 K. This study clearly indicates the existence of Moss-Burstein shift in the visible region and Pauli blocking effect in the NIR region in the Bi 2 Se 3 topological insulator. Moreover, the low-temperature TRUS confirms the transition to the second surface state present in bismuth selenide. [ABSTRACT FROM AUTHOR]

Abstract: The effect of substrate bias on the structural, morphological, electrical and mechanical properties of hydrogenated amorphous carbon films having embedded nanocrystallites deposited by cathodic jet carbon arc technique has been investigated. X-ray diffraction exhibits predominantly an amorphous nature of the film with nanocrystallites of diamond embedded in the amorphous carbon matrix. High resolution transmission electron microscope investigations reveal largely a uniform amorphous structure. However, an ultra fine microstructure with the average grain size between 8 and 25nm was constituting the entire film with the diffused grain boundaries between the grains. Majority of the individual grains are single crystallite with the preferred inter planar spacing of about 0.213nm and 0.208nm corresponding to the diamond planes of 102 and 103, respectively. All the evaluated parameters were seen to depend strongly on the negative substrate bias and exhibit maxima or minima in the properties of the films deposited at −60V substrate bias. [Copyright &y& Elsevier]