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In this work, we consider a hybrid aerial full-duplex (FD) relaying protocol consisting of a reconfigurable intelligent surface (RIS) mounted over an FD unmanned aerial vehicle (UAV) relay operating in the decode and forward mode to assist the information transfer between the base station and multiple users. For better spectral efficiency, we investigate the use of non-orthogonal multiple access (NOMA) in such networks and focus on both the performance analysis and design optimization of the considered RIS-NOMA network under imperfect channel state information (CSI) and successive interference cancellation (SIC) at each user, and residual-self interference (RSI) at UAV. We first formulate the sum rate maximization problem and adopt the block coordinate descent method to deal with the non-convex nature of the problem. Thereafter, we propose an algorithm based on the Riemannian conjugate gradient method to get the optimal phase shifts at the RIS, an iterative algorithm to obtain the optimal UAV/RIS position and the exhaustive method to obtain the optimum power allocation coefficients. Next, with obtained optimal position, phase shift and power coefficients, we further analyze the performance of the network and derive the closed-form expressions of outage probability, achievable throughput and ergodic capacity. We present Monte Carlo simulation-based results to validate the accuracy of the proposed algorithms and derived expressions and demonstrate the superiority of NOMA over OMA. [ABSTRACT FROM AUTHOR]

Owing to the factors such as controllable mobility, ready-to-use technology, low cost, easy implementation, and so on, unmanned aerial vehicle (UAV) possesses tremendous potential to be one of the primary candidates for next-generation (6G) wireless networks. This paper presents a UAV-assisted multiuser communication network where a multiple antenna UAV base station (BS) serves multiple single antenna ground users (GUs). UAV-BS uses a laser source-based charging mechanism to fulfill its power requirement and applies simultaneous wireless information and power transfer (SWIPT) in the downlink in order to provide desired power to energy-constrained GUs. Also, a clustering-based hybrid multiple access technique is used that combines both orthogonal multiple access (OMA) and non-orthogonal multiple access (NOMA) signaling to transmit the information to all GUs, simultaneously. Due to the involved analytical complexity corresponding to the multiple antennas and users, we use a hybrid beamforming method for efficient communication. Next, we analyze the performance of the proposed framework in terms of user outage probabilities, their respective throughput, and average power harvested considering non-linear energy harvesting and derive expressions of these performance metrics. Moreover, we formulate an optimization problem where the throughput of one GU is maximized by optimally choosing the power allocation parameter while ensuring the desired target throughput at other GU in each cluster. We also illustrate how crucial is the optimal selection of the target rates to maximize the network performance. Simulation results are provided to validate the accuracy of derived expressions and to highlight the dominance of hybrid beamforming and hybrid NOMA compared to conventional methods on the performance of the considered network. [ABSTRACT FROM AUTHOR]

This paper investigates the performance of a new framework for low-outage downlink non-orthogonal multiple access (NOMA) using a coordinated direct and relay transmission (CDRT) scheme with direct links to both the near-user (NU) and the far-user (FU). Both amplify-and-forward and decode-and-forward relays are considered. In this framework, the NU combines the signals from base-station and relay at each stage of the successive interference cancellation (SIC) to attain good outage performance. For both NU and FU, the expressions for outage probability and throughput are derived in closed form. We also derive the high-SNR expressions for the outage probability to demonstrate that with the proposed framework, both users harness a diversity of two without feedback bits (this is the only framework to achieve this). We demonstrate that the choice of power allocation coefficient and target symbol rates is crucial to maximizing the NU throughput while ensuring a desired target FU throughput. We demonstrate that CDRT with the proposed framework outperforms known schemes in terms of outage probability, sum throughput, and energy efficiency. Moreover, we also show that optimal rate selection is important to maximize the energy efficiency. Monte Carlo simulations validate the accuracy of the derived analytical expressions. [ABSTRACT FROM AUTHOR]

This paper investigates the performance of a non-orthogonal multiple access (NOMA) network with simultaneous wireless information, and power transfer (SWIPT) based battery-assisted energy harvesting (EH) full-duplex relay (FDR). In each signalling interval, the base-station communicates directly to a near user (NU), and through an EH FDR to a far user (FU). Considering the power-splitting (PS) protocol with a non-linear EH model, we derive closed-form expressions for the NU, and FU outage probabilities. We also demonstrate how the battery energy, and PS parameter can be chosen to maximize the FU throughput while ensuring a desired NU throughput when there is imperfect interference cancellation at the NU. Computer simulation results validate the accuracy of the derived expressions, and demonstrate that augmenting the harvested energy with a small quantum of the relay's battery energy can considerably improve the FU performance. [ABSTRACT FROM AUTHOR]

In the present experimental work, two identical real field experimental setups (with dry soil and wet soil) of ground-air heat exchanger (GAHE) have been developed in order to evaluate the influence of change in inlet air temperature, airflow velocity, diameter of pipe and soil moisture content on the thermal performance of GAHE system. Influence of these parameters on the required pipe length to produce a specified drop in air temperature has also been investigated. Results reveal that the drop in air temperature achieved from GAHE having dry soil is 11.2 °C at 60 m pipe length, whereas, for GAHE with wet soil having 20% moisture, the same amount of drop in air temperature is obtained at a pipe length of 28 m only. Moreover, upon increasing the airflow velocity from 2 m/s to 10 m/s, cooling capacity of GAHE with dry soil, wet soil with 5% moisture and wet soil with 20% moisture increases by 122%, 185% and 220%, respectively, after 6 h of operation, but the effectiveness of the GAHE system with dry soil, wet soil with 5% moisture and wet soil with 20% moisture decreases by 55.4%, 42.5% and 36.2%, respectively. • Development of an outfield experimental set up for GAHE system with dry and wet soil. • 53% length of GAHE pipe can be reduced by using wet soil with 20% moisture. • By increasing air flow velocity 2 m/s to 10 m/s, cooling capacity increases 220% in wet soil. • By increasing air flow velocity 2 m/s to 10 m/s, effectiveness decreases 36.2% in wet soil. • Required length of GAHE pipe highly depends on soil moisture, air velocity and pipe diameter. [ABSTRACT FROM AUTHOR]

Thermal performance of ground-air heat exchanger (GAHE) depends on the rate of heat transfer between air and soil, which is governed by thermal properties of soil surrounding the GAHE pipe. Soil thermal properties around GAHE pipe can be improved either by increasing its moisture contents or by using some thermally enhanced backfilling materials. In the present study experimentally investigates the thermal performance of ground-air heat exchanger system using a sand-bentonite mixture (dry as well as wet) and compare their performance with the ground air heat exchanger system having native soil (dry as well as wet) as backfilling material. The study acknowledges the highest cooling capacity (125 W) for GAHE with wet sand-bentonite as backfilling material, and after 6 h of continuous operation, it is 38.4%, 18.4% and 11.1% higher than that obtained with dry native soil, dry sand-bentonite and wet native soil, respectively. The study also revealed that thermal performance deterioration factor (TPDF) increases with the duration of the operation. At airflow velocity of 5 m/s, after 6 h of continuous operation highest TPDF is noticed for ground-air heat exchanger with dry soil (0.22); whereas, lowest TPDF is observed for ground-air heat exchanger system with wet sand-bentonite (0.07). Schematic of laboratory experimental setup of GAHE system. Image 1 • Development of a laboratory scale experimental set up for GAHE system. • To evaluate the effect of sand-bentonite backfilling material (dry as well as wet) on performance of GAHE system. • Maintaining a certain level of moisture into the soil in the close vicinity of GAHE pipe. • Better thermal performance of GAHE due to BFM resulting reduction in required pipe length. [ABSTRACT FROM AUTHOR]

• Earth air heat exchanger system is one of the promising passive techniques for building heating and cooling application. • Efficiency and utility of the EAHE system increase by coupling it with other active/passive systems. • EAHE system may be a good option for pre-heating and pre-cooling of air in industrial applications. • Large land area required to install EAHE is a major constraint for the adaptability of EAHE system in urban areas. • The required pipe length of EAHE can also be reduced by using soil of high thermal conductivity at the vicinity of the pipe. Earth air heat exchager (EAHE) is a promising passive technique that utilises the constant temperature of the underground soil for heating/cooling of air. The EAHE system possesses several advantages and can be used stand-alone as well as in hybrid mode for heating/cooling of air for building and commercial/ industrial applications. This article reviews the available literature pertaining to technology integration and applications of earth air heat exchanger system in the last four decades and also account for the recent significant developments in EAHE to indicate the emerging trends in the domain. The comprehensive review of the literature suggests that a standalone EAHE system can does not cater the requirements of thermal loads entirely and therefore has not grown much popular and still vying for commercial/ industrial applications, worldwide. The requirement of auxiliary devices so as to supplement the standalone EAHE system to achieve thermal comfort conditions entailing huge expenses conflicts the economics of the hybrid EAHE systems. The exorbitantly increasing costs of pipes, land and labour necessitate the paradigm-shift in the major thrust of the research associated with thermal comfort so as to incorporate the economics of system as a whole to enhance the acceptability of EAHE system. [ABSTRACT FROM AUTHOR]

Highlights • Fabrication of a unique sub-soil water trickling system (SWTS) integrated with EAPHE system. • Three soil moisture content values viz. 5%, 10%, and 15% have been considered for wet EAPHE system. • Investigation of the effect of soil moisture variation on thermal performance of EAPHE system. • Comparison of thermal performance of dry and wet EAPHE system for winter heating. • Estimation of heat transfer rate, COP and knee point position for dry and wet EAPHE systems. Abstract Earth-air-pipe heat exchanger (EAPHE) system is a passive system but requires long pipes for heat transfer and its performance also gets deteriorated during continuous operation. In this study, the moisture content of sub-soil is increased in the close vicinity of EAPHE pipe and its influence on thermal performance and pipe length requisite for certain temperature rise in winter season have been determined. The system comprises of two identical set-ups of EAPHE system buried at a depth of 3.7 m (one for dry soil, other for wet soil). A unique water impregnation system is presented to maintain different soil moisture content levels in the close vicinity of EAPHE pipe. The knee point for dry EAPHE system is obtained at a pipe length of 40 m from inlet section while in wet EAPHE system knee point is obtained at 28 m, 27 m and 26 m with 5%, 10%, and 15% soil moisture levels respectively, after 12 h of continuous operation. The average heat transfer rate and coefficient of performance increase up to 26.0% and 26.1% respectively, for 15% moisture content at 30 m length of EAPHE pipe as compared to dry system. [ABSTRACT FROM AUTHOR]

Highlights • The Earth air tunnel heat exchanger system is capable to provide sufficient heating and cooling in buildings with significant energy savings. • The knowledge of thermo-physical properties of soil is crucial for the design of an EATHE system. • In multiple pipe system, the distance between the pipes should be reduced gradually along the length of pipe. • Too deeper excavation of soil does not result in any appreciable change in soil temperature. • EATHE should be used during daytime in summer and during night time in winter season. Abstract The principal drivers that led to the high growth rate in the renewable energy market in developing countries over the past twenty years include not only the dwindling fossil reserves, exorbitant increase in the price of crude oil, widening energy deficit, but also the extravagant lifestyle of profligate consumers of energy. Nearly one-third of total primary energy is consumed for the purpose of space cooling and heating. Renewable and passive systems can reduce the building cooling and heating energy demand. Earth air tunnel heat exchanger system is one of the promising technique used for space cooling and heating nowadays, thus reduce fossil fuel based energy demand as well as greenhouse gas emission, but its use has been restrained owing to its poor performance, land area requirement and financial viability. Various experimental, analytical and simulation studies have been conducted in last few decades to investigate the various parameters that may enhance its performance. In this article, the effect of thermo-physical parameters of soil, thermal and flow parameters of air, geometrical and material properties of pipe, different modes of operation on the performance of earth air tunnel heat exchanger systems have been critically reviewed. Following thorough review of the articles, it is concluded that if EATHE system is developed with proper design guidelines, then it may facilitate sufficient space heating and cooling with significant energy savings. [ABSTRACT FROM AUTHOR]

An EATHE system performs well for short periods but its thermal performance gets deteriorated during long continuous operation due to sub-soil thermal saturation in the vicinity of buried pipe. Effect of soil thermal saturation can be reduced to some extent in longer EATHE pipe but it is uneconomical. In the present study sub-soil moisture content is increased to enhance soil thermal properties and its effect on EATHE thermal performance and pipe length requirement for certain temperature drop has been investigated experimentally for summer cooling in hot and arid climate. In the study, two identical experimental set-ups have been developed at Ajmer city (India). A water impregnation system has been introduced to maintain different soil moisture contents in the close proximity of EATHE pipe. Knee point is obtained at a length of 29 m, 28 m, 27 m and 26 m from pipe inlet section with 5%, 10%, 15% and 20% moisture in sub-soil respectively, as compared to 41 m length in dry soil, after 10 h of continuous operation. The average heat transfer rate and COP increased by 24.1% and 24.0% respectively for 20% moisture content at 30 m EATHE pipe length as compared to dry system. [ABSTRACT FROM AUTHOR]

• Evaluated economic feasibility of backfilling materials for GAHE system. • Developed a CFD simulation model for GAHE system with backfilling materials. • Use of backfilling materials to improve the overall economics of GAHE system. • Required length of GAHE pipe is determined with different BFMs. The ground-air heat exchanger (GAHE) system is an energy-efficient system for building cooling/ heating, but its initial cost is higher due to the requirement of longer pipes to achieve the desired heat exchange between air and soil. To reduce required pipe length, secondary soil (i.e. soil of high thermal conductivity) can be used as backfilling material in the vicinity of GAHE pipe. However, due to the use of secondary soil, the installation cost of the GAHE system may increase. Therefore, the key objective of this study is to explore the economic feasibility of using backfilling materials in the vicinity of GAHE pipe. For this, a three-dimensional CFD simulation model of GAHE system with backfilling material has been developed using FLUENT 15.0, and the required length of GAHE pipe to achieve a specified drop in air temperature with backfilling materials has been determined. Based on this, the initial installation cost of the GAHE system (i.e. pipe cost, trench excavation cost, backfilling material cost) has been estimated. The study revealed that the initial installation cost of a GAHE system could be reduced by 25.7%, 32%, and 38% using dry sand-bentonite, wet sand-bentonite, and wet native soil respectively, as backfilling materials in place of dry native soil. [ABSTRACT FROM AUTHOR]

• Development of a laboratory scale experimental set up with slinky-coil pipe layout. • Use of sand–bentonite mixture as backfilling material for GAHE system. • Required length of the trench is reduced by using slinky-coil pipe layout. • Substantial saving in terms of excavation cost and piping cost. The ground-air heat exchanger (GAHE) is the promising passive technique for building heating/cooling, but due to its high installation cost (mainly pipe cost and excavation cost), it could not become popular. The required length of pipe can be reduced by using thermally enhanced backfilling material (BFM), while, the length of the trench can be reduced by using slinky-coil pipe layout. In the present study, an experimental laboratory setup of GAHE system has been developed with a slinky-coil pipe layout and sand-bentonite as BFM. For this, a flexible PVC pipe of 75 mm diameter and 30 m length, has been arranged in slinky-coil pattern and installed horizontally in a soil box of 10.2 m length. For the study, variation in soil temperature (23 °C–27 °C), inlet air temperature (38 °C–46 °C), air flow velocity (5 m/s–20 m/s) and soil conditions (dry and wet), have been considered. Study reveals that a drop-in air temperature as high as 18.7 °C at 30 m pipe length (trench length of 10.2 m) can be achieved with soil at a temperature of 27 °C and inlet air temperature of 46 °C. The study also revealed that the pipe length could be reduced by 20% with wet sand-bentonite as compared to dry sand-bentonite. [ABSTRACT FROM AUTHOR]

A field experiment was conducted in spit plot design with three replication to "to study different rice establishment methods on growth, yield and different varieties" was conducted at Agronomy farm, College of Agriculture, Dapoli, Distt. Ratnagiri (M.S.) during kharif season of 2014 on was sandy clay loam in texture, moderately acidic in pH (5.63), medium in organic carbon content (0.82 %), electrical conductivity (Ec) 0.035 dSm-1 , medium in available nitrogen (284.82 kg/ha), low in available phosphorus (14.63 kg/ha) and high in available potassium (248.45 kg/ha). The highest plant height (71.09 cm), effective tillers (360.58 m2), length of panicle (21.07 cm), test weight (22.24 g), straw yield (47.42 q ha-1), weight of per panicle (2.15 g), number of filled grains per panicle (97.08) and B:C ratio (1:2.23) were recorded in line transplanting technique. Based on the results obtained, it can be concluded that in areas where labour is available and cheap, transplanting as per as recommended (21 days old age seedling) is a better establishment methods of rice because it produces more yield and gross monetary economic return than other methods. [ABSTRACT FROM AUTHOR]

Earth air tunnel heat exchanger (EATHE) systems are inadequate to meet the thermal comfort requirements in semi-arid regions as they require large pipe lengths. The effectiveness and performance of such system can be increased by increasing soil moisture content, making as wet soil configuration. In the present work, the thermal performance of the EATHE system with dry and wet soil has been evaluated during the peak summer season. Further, the thermal behavior of these two EATHE systems has been compared on the basis of temperature of air flowing through buried pipes at different sections along the length. For the same a theoretical model is developed and validated with experimental results and found in good agreement with an error ranging from 2.44% to 10.85%. Moreover, the exergetic analysis has been carried outto investigate the work potential and scope of maximum utilization of energy. Results reveal that thepipe length can be reduced by 12–14 m with wet EATHE system as compared to dry EATHE system for the same cooling performance. The second law analysis shows that the maximum exergetic efficiency is 52.25% and 53.18% for dry and wet soil EATHE systems respectively. [ABSTRACT FROM AUTHOR]

Background/aim: India has 63 million diabetic people and the overall prevalence of diabetes in this country is 8.37%. Lifestyle modification by education is the most cost-effective strategy to have better metabolic control. The aim of this study was to investigate the effects of a self-management educational program on control of type 2 diabetes. Materials and methods: It was a randomized controlled interventional study conducted among 306 patients with type 2 diabetes mellitus attending the Diabetic Clinic at G.T.B. Hospital, Delhi, from March 2010 to May 2013. The intervention was in the form of group education based on a self-management program, which was earlier developed in the pilot study. Results: The baseline characteristics were comparable in the two groups. After 6 months, there was a significant improvement in the HbA1c levels (P = 0.0001), physical activity level (P = 0.001), and BMI (P = 0.001) in the study group as compared to the control group and this difference persisted even when analysis was done using generalized estimation equations. Conclusion: The findings of this study proved that a self-management educational program is an essential component in the management of diabetes and provided concrete evidence that this is an effective instrument in the control of body weight, blood pressure, and glycated Hb levels in type 2 diabetes. [ABSTRACT FROM AUTHOR]

Background and Aim: The risk of acquiring hepatitis B virus (HBV) infection through exposure to blood or its products is highest amongst health care workers (HCWs). Despite potential risks, a proportion of HCWs never get vaccinated. India is second to China in the numbers of people with chronic HBV. This study aimed to investigate the vaccination practices and the prevalence of HBV infection in HCWs in India. Methods: A total of 2162 HCWs were screened for the presence of serological markers of HBV and hepatitis C virus (HCV). Occult HBV infection was tested by detection of HBV-DNA for surface and core regions by nested polymerase chain reaction in HBsAg-negative and IgG anti-hepatitis core antigen–positive subjects. Results: Only 1198 (55.4%) of the 2162 HCWs screened had been vaccinated; and 964 (44.6%) were not vaccination-status conscious; of these HCWs, 600 (27.7%) had never been vaccinated and 364 (16.4%) were unaware of their vaccination status. Protective (> 10 IU/mL) anti-hepatitis B surface (anti-HBs) antigen titers were seen in only 61.7%. The anti-HBs titers were found to be lower with the passage of time; the median anti-HBs titers in subjects who were vaccinated > 10 years ago were significantly lower than those who had been vaccinated < 5 years ago ( P < 0.001). One percent of HCWs were HBsAg-positive, and 24.7% of 700 HCWs screened had past exposure (IgG-anti-HBc-positive). Occult HBV was detected in 5% of 120 positive subjects with past exposure; all had anti-HBs titers > 10 IU/mL. Conclusions: Even today, 28% HCWs in India are unvaccinated and 17% are unaware of their vaccination status. This data suggests that use of hepatitis B immune globulin be mandatory in needle-pricked HCWs in India, and that implementation of awareness strategies is urgent. Since the anti-HBs titers decline in a fair proportion, there is justification for giving a booster dose of vaccine 10 years after primary vaccination to HCWs in India. [ABSTRACT FROM AUTHOR]

Abstract: The non-response to hepatitis B vaccine in health care workers (HCWs) is reported to vary between 5 and 40%. The underlying cellular and molecular events for unresponsiveness to HBV vaccine have not yet been characterized at any great extent. In the current study, we examined the CD150 surface expression levels and its association with polyclonally activated and HBV specific stimulated cellular proliferations in responders and non-responders. CD150 was identified as upregulated expression marker with suppressive regulatory cell function on all activated T cells by gene chip analysis. We found the overall weak cellular proliferation in response to specific and non-specific agents in non-responders. This is significantly associated with enhanced surface expression of CD150 in the non-responders. A strong expression of CD150 with weak cellular proliferation could be used as a predictive marker for non-responsiveness. [Copyright &y& Elsevier]