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In the event of a natural disaster such as a flood, cyclone, or tsunami, often the communication infrastructure gets damaged or becomes non-functional. In such scenarios, small cells covered by unmanned aerial vehicles (UAVs) are used to extend seamless cellular connectivity to the non-functional area (Mozaffari et al. in 2015 IEEE Global Communications Conference (GLOBECOM), IEEE, pp 1–6, 2015). This stand-in infrastructure is essential for sharing rescue-related information to the on-field rescue hubs and collecting real-time information from the devastating site to deliver to the outside world. Moreover, in such scenarios, it is possible that the Device-to-Device (D2D) nodes at the ground may have depleted battery power and hence are unable to transmit or receive information. In this paper, we propose a novel UAV-assisted multi-hop D2D communication model with energy harvesting for such a disaster scenario. In the proposed model, the best path from the UAV to the destination out of multiple D2D options is selected following a modified Dijkstra's algorithm. We develop analytical expressions for the end-to-end outage probability, ergodic capacity, and throughput in the multi-hop D2D links for making communication possible in the disaster zone. We evaluate the performance of the proposed scheme and observe significant improvements in terms of various network attributes. [ABSTRACT FROM AUTHOR]

In the future, intelligent transportation systems will rely heavily on vehicle to vehicle (V2V) communication-based cooperative vehicular networks since they can provide several applications for tackling traffic congestion and road safety. Future 6G and New Radio 5G (NR5G) technology will facilitate improving cellular vehicle to everything (CV2X) communication performance. Cellular-assisted V2V communications, in which cellular evolved Node base stations (eNBs) relay the transmission from one vehicle to another, have lately been proposed to overcome the performance restrictions of conventional dedicated short-range communication (DSRC) protocols (Kimura in IEEE Trans Veh Technol 70(4): 3396–3411, 2021. 10.1109/TVT.2021.3063694). These cellular-aided communications have demonstrated the potential for more reliable V2V communications with a larger capacity and longer transmission distances. In this paper, we theoretically examine the effectiveness of cellular vehicle to everything communications, where a vehicle broadcasts a message to its nearby vehicles or user equipment (UEs). It happens in two ways, i.e., direct vehicle to vehicle and via the closest eNB through an uplink. Then the closest eNB forwards the message to the destination vehicle via downlink i.e., vehicle to network (V2N) or vehicle to infrastructure (V2I). To obtain a suitable model for estimating the Bit Error Rate (BER) and the Packet Error Rate (PER), we consider the movement of three vehicles are in a straight line on the roadways with different velocities. Using numerical examples, we assess the analytical findings and show how different system factors affect the effectiveness of CV2X communications. A simulation has been carried out in the network (system) level context. [ABSTRACT FROM AUTHOR]

In the current work, the analyti cal static gravimetric technique was used to assess the solubilities of DL-α-amino butyric acid and DL-valine in an aqueous binary solvent mixture of sodium sulfate (Na2SO4) under equilibrium saturation conditions in between temperature range 288.15 and 308.15 K. Different thermodynamic factors along with transfer Gibbs energetics and entropies under standard conditions were estimated by using computational as well as theoretical method by using the experimental solubilities. Several modes of interactions that occur during solvation were also explained. The manner that solvent molecules of solute amino acids are surrounded in the aforementioned medium employed during the process is taken into consideration. Amino acids become more soluble as the temperature rises. The study also helps us to reach the conclusion that physical properties of electrolyte (Na2SO4), mixed solvent, and the size of the amino acids' molecules are the main governing factors for the chemical stability as well as other thermodynamic and physical property like solubility of solute amino acids. [ABSTRACT FROM AUTHOR]

Herein, non-conventional lanthanum phosphate (LaPO4) nanospheres were synthesised in water-in-oil (W/O) microemulsion (Tween 20/1-butanol/water/toluene) scaffolds and employed in the assessment of surfactant-free TiO2-based Pickering emulsion formulations. TEM and FESEM microstructural analyses were carried out to examine the nanospheres inside the core of the reverse micelles. Both types of electron microscopy identified two distinct phases in the growth of the nanospheres: a nucleation phase (5–15 min) in which only nanospheres of smaller dimensions were seen and a growth phase (15–60 min) wherein larger dimensions nanospheres were observed. LaPO4 nanospheres are extremely hydrophilic and alone would fail to provide stability to the oil-in-water (O/W) Pickering emulsions and consequently require in situ hydrophobization. The determined zeta potentials suggested that the LaPO4 nanospheres have a positive surface charge (+57 mV) and eventually, oppositely charged solid TiO2 nanoparticles were therefore introduced onto the surface of the synthesised LaPO4. The adsorption of TiO2 ensured the evaluation of the amphiphilic nature of the nanospheres through the formation of LaPO4@TiO2 nanocomposites. Additionally, TEM analysis supported that no morphological alterations occurred upon the adsorption. The as-prepared nanocomposites thereafter started to provide extra stability (due to the lower interdroplet coalescence) to the O/W Pickering emulsions, which could be sustained for up to 4 weeks and even more. The stability of the emulsion droplets was supported by the optical micrography analysis. Moreover, such an attainment of stability therefore, successfully opens a new idea for obtaining surfactant-free stable Pickering emulsion formations. [ABSTRACT FROM AUTHOR]

Summary: This paper analyzes the performance of a cooperative nonorthogonal multiple access (NOMA) in an underlay cognitive radio network aided by an energy harvesting relay. A secondary source transmits signal for two users, where a near user acts as a relay for the far user. The far user applies the selection combining (SC) approach on the signals which were relayed by the near user and received via direct path from the secondary source. We analytically derive the outage probability (OP) of each user separately, the overall system OP, and the throughput of the system. The impact of the power allocation coefficient of NOMA and energy harvesting parameters on outage is indicated. Further, the performance of the network is investigated with imperfection in successive interference cancellation (SIC), maximal ratio combining (MRC) at relay, and Nakagami‐m fading. The results derived analytically are supported by simulation in MATLAB. [ABSTRACT FROM AUTHOR]

Summary: This paper considers a dual‐hop cooperative relay‐based communication with uplink (UL) and downlink (DL) non‐orthogonal multiple access (NOMA), where communication between sources to destinations takes place parallelly in the same frequency band over a Rayleigh fading channels. The energy harvesting (EH)‐based full‐duplex (FD) relay helps in forwarding the message from the source node to the destination node via superposition coding, thus calling it a multiple sources full‐duplex energy‐harvesting cooperative relay NOMA (MS‐FD‐EH‐CR‐NOMA) system. Early works focus on EH from one source node or a dedicated power station. In this article, the communication between sources and destinations occurs in two slots where first slot deals with energy harvesting while in second slot information transmission occurs. We studied the effect of imperfect successive interference cancellation (ipSIC) and residual self‐interference (RSI) in decoding the message at the relay and the destinations. We derived the closed‐form expressions for the outage probability of each pair and the system outage probability of the MS‐FD‐EH‐CR‐NOMA system. Next, we derive the closed‐form expressions of ergodic capacity under Rayleigh distributed fading channels. Further, numerical results are validated by its simulation results using Monte Carlo simulations in MATLAB. The results obtained through this work are a good step towards designing multiple source–destination communication using NOMA and EH relay. [ABSTRACT FROM AUTHOR]

This paper investigates a novel full-duplex (FD) simultaneous wireless information and power transfer (SWIPT) based cooperative non-orthogonal multiple access (FDS-NOMA) system, where far distant NOMA IoT users are helped by the NOMA strong user with the capability of energy harvesting (EH) and FD communications. The downlink (DL-NOMA) principle is used to transmit the superimposed signals from source i.e a base station (BS) to an energy-limited FD relay where relay harvests energy from the transmit power of the BS. The relay after detecting the superimposed signals using successive interference cancellation (SIC), retransmits the decoded signals using superposition coding to the IoT users. We derive the analytical expressions of the outage probability and ergodic rates experienced by the NOMA strong user as well as NOMA IoT users. The results shows that proposed cooperative NOMA scheme can be used to serve IoT users using EH relay. Extensive simulations are performed to verify the accuracy of the derived approximate closed-from expressions. [ABSTRACT FROM AUTHOR]

Summary: An unmanned aerial vehicle (UAV)‐assisted communication is a promising technique for enabling ground users in a non‐functional area (NFA) or disaster area to communicate. All the base stations in the disaster area may be partially or fully damaged due to the natural calamity. Device‐to‐device (D2D) communication can be a viable solution for immediate connection between users in an NFA. We propose a UAV‐assisted multi‐hop D2D communication following a hybrid power‐time switching (PTS) in this paper. Moreover, a D2D user of a cluster can communicate with another D2D user in a different cluster through UAVs. However, D2D users can harvest energy from their respective ad hoc energy stations and forward the information to the nearby D2D user following a hybrid PTS‐based strategy. We propose a time frame for the same and show a node‐based energy harvesting strategy. The expressions of outage probability, throughput, end‐to‐end energy consumption, and energy efficiency are developed for the Rician and Nakagami‐m faded channel. The impact of several network parameters such as energy harvesting factor, energy harvesting efficiency, and fading parameter on the network performance is also indicated. [ABSTRACT FROM AUTHOR]

We demonstrate herein the first example of K2S2O8 mediated direct C(sp2)−Hthiocyanation of substituted 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones at room temperature in the absence of a metal catalyst. This unique approach features a broad substrate scope with excellent functional group tolerance and substitution patterns, affording the target thiocyanated scaffolds in lucrative yields with exclusive regioselectivity. Mechanistic investigations have also been conducted for better understanding of the reaction pathway. In addition, the synthetic utility of this protocol has been showcased through the construction of biologically relevant analogues. [ABSTRACT FROM AUTHOR]

The present study tells us about the solubility of DL-α-amino butyric acid (DL-α-Aba) in aqueous binary solvent mixture of sodium sulfate under equilibrium saturated condition through analytical gravimetric method at equidistant temperature. Different thermodynamic factors along with transfer Gibbs energies and entropies under standard condition were estimated by using theoretical methods and by the experimental solubilities. The way of surrounding by solvent molecule of solute amino acid in the said media used through the process and is discussed on the ground of different mode of interactions occurring at the time of solvation. Amino acid (DL-α-Aba) shows more solubility with rising temperature. The study reveals that physical properties of electrolyte (Na2SO4), mixed solvent and the size of the amino acid (DL-α-Aba) molecule are the main governing factors for the chemical stability of solute DL-α-Aba. [ABSTRACT FROM AUTHOR]

This article presents mole fraction solubilities of l-tryptophan in binary aqueous methanol solvent systems and applied them to estimate thermodynamical parameters like transfer Gibbs free energetics and entropies of solutions. The estimated thermodynamic energies were linked with interaction parameters like dipole–dipole interactions, enthalpy due to transfer of l-tryptophan from water to binary water–methanol solvent mixtures. The transfer Gibbs free energetics for chemical interactions and entropies for solvent–solvent interaction were calculated by mathematical relations. The chemical transfer energetics was applied to explain the probable stability of l-tryptophan in the mixed solvents. Many associated thermophysical parameters were also calculated at standard temperature (298.15 K). [ABSTRACT FROM AUTHOR]

In this study, we investigated the solubility of coumarin in aqueous solution and binary mixtures of N,N-dimethylformamide (DMF), acetonitrile (ACN), and dimethylsulfoxide (DMSO) through experimental measurements. The solubility experiments were carried out using the analytical technique of UV-Vis spectroscopy in a temperature range of 288.15–308.15 K under atmospheric pressure using a digital temperature controlling thermostat. Water–DMF mixture system exhibited the highest solubility of coumarin, whereas water–ACN system showed the lowest solubility among the studied solvent systems. To gain a deeper understanding of the solvation process, we employed theoretical studies to optimize the molecular structure of the compound. This optimization enabled the calculation of significant molecular properties, such as close molecular dimension and dipole moment, which play key roles in determining various thermodynamic parameters associated with solvation. By utilizing the measured solubilities, we analyzed the thermodynamic properties of coumarin dissolution, including the Gibbs free energies of the solutions, transfer Gibbs free energies related to cavity formation and dipole–dipole interactions, transfer enthalpy of dissolution, and chemical transfer energetics. These analyses aimed to provide insights into the thermodynamic stability of coumarin-like compounds in solution. [ABSTRACT FROM AUTHOR]

Secrecy performance of a cooperative communication network is analyzed in which source transmits information to a destination via multiple relays, assisted with multiple antennas, where an eavesdropper is able to eavesdrop the information signal from relay only. The direct link does not exist between source and destination due to deep fading and shadowing effect and transmission of a signal from source to destination is completed in two phases; first is the broadcasting phase and other is the relaying phase. Each relay follows decode and forward protocol and receives the information signal with multiple antennas. A selected relay harvests energy from received multiple signals through multiple antennas. Both information and jamming signals are transmitted by the selected antenna of a selected relay. It has been seen that a selected relay harvests energy 0.3706 joule with an array of 5 antennas when the source transmits the information signal with 5 dBW power. We have also observed that the performance increased by 99.24 % in case of an array four antennas system with respect to an array of two antennas system when secrecy threshold is 1 b i t / s / H z . Secrecy performance is measured in terms of secrecy outage probability (SOP). A closed-form expression of the SOP is derived to analyze the secrecy performance which is verified by the simulation results. [ABSTRACT FROM AUTHOR]

The solubility and thermodynamics of solvation due to solute–solvent interactions of glycine, DL-alanine, DL-serine, and DL-valine were determined in this study. Mainly, the transfer of Gibbs free energies from aqueous to aqueous sodium and potassium iodide salt solutions was considered, which were calculated by direct experimental solubility data and via theoretical calculations. The equilibrium solubilities were measured at 298.15 K using simple "formol titration". Various important physicochemical factors like enthalpy of solvation, molar volume, molar mass, molar density, etc., in aqueous electrolyte solutions were calculated at standard temperature. The thermodynamic parameters were explained to conclude about the virtual stability of the zwitterionic solutes in aqueous salt mixtures. The factors that are associated with solubility were also explained and correlated with physical and thermodynamic point of view. [ABSTRACT FROM AUTHOR]

Non-orthogonal multiple access (NOMA) is an emerging technique for improving wireless connectivity mostly for upcoming fifth generation (5G) networks. An unmanned aerial vehicle (UAV) assisted downlink NOMA network is considered for the first hop to serve the ground users in a non-functional area (NFA). An NFA indicates the region where the base station (BS) gets damaged due to some natural disasters in a two-hop communication. A device-to-device (D2D) communication is a favourable 5G technology, as it supports direct communication between users without traversing the BS. Furthermore, simultaneous wireless information and power transfer (SWIPT) enabled downlink NOMA assisted D2D network is proposed for the second hop to cover the non-functional or disaster area. In the first hop, we derive the outage probability for both the multiple access schemes, i.e., orthogonal multiple access scheme (OMA) and NOMA. OMA and NOMA to determine whether communication from the first ground node to the destination node is justified. Thereafter, we calculate the sum rate and total power consumption for the second hop to maximize the energy efficiency (EE) in our proposed SWIPT enabled NOMA-based D2D network. To tackle this problem, the Dinkelbach method (Zhao et al. in IEEE Trans Commun 67(5):3723–3735, 2019) is applied for optimizing the power allocation problem to maximize the EE in the network. In addition, a multiple interference cancellation scheme (MIC) is used to get the desired signal at the receiving end. Finally, analytical and simulation results are shown. [ABSTRACT FROM AUTHOR]

Oxygen support became one of the rate-limiting steps for medical care during COVID-19 pandemic in India. The primary aim of this study was to appraise the manufacturing, supply, and distribution of medical oxygen during the pandemic. The secondary objectives were to highlight the coordination of various stakeholders to mitigate the oxygen surge and to present a critical analysis of India's response to the emergent situation. Using an analytic approach, we have delineated India's response to mitigate the medical oxygen surge during the distressing second peak between March–May 2021. In the pre-COVID-19 era, of the total 6900 MT of oxygen produced in India, only 1000 MT was available for medical usage, which was increased up to 19940 MT through the strengthening of in-house oxygen manufacturing, low-cost innovations, and enhanced storage facilities. High-burden states were identified, and transport was facilitated through departments of railways, defence and civil aviation. Real-time scrutiny of the oxygen supply was provided. Essential customs duties on importing oxygen and vital equipment were exempted, along with other swift decisions. National Oxygen Stewardship Program' was initiated to build the capacity of health care workers in oxygen therapy and rational use of surplus oxygen. The pandemic overwhelmed the health system. But a coordinated multi-stakeholder approach facilitated the fight against oxygen surge. However, a comprehensive pandemic response will need more than just oxygen. This resourceful utilization offers a silver lining and facilitates the improvement of health systems and health outcomes in the long term. [ABSTRACT FROM AUTHOR]

The solubility of few amino acids is very significant in biological action of biomolecules like proteins. In the current work the solubilities of L-cysteine in NaCl aqueous solution with variation of temperature were measured by gravimetric technique. The thermodynamical energetics and interactions effects were estimated under the experimental conditions as mentioned above. Other essential and associated solvent parameters like molar volume, molar mass, etc., were also calculated in this study. Different interactions mainly molecular interactions were clarified to discuss the role of solute and solvent in solvation phenomenon. [ABSTRACT FROM AUTHOR]

The solubilities of DL-Phenylalanine change with increasing concentration of N,N-dimethylformamide (DMF) solution. The solubilities of DL-Phenylalanine were measured by "formol titration" in temperature range from 288.15 to 308.15 K. Variation of solubility helps to measure the changes of the thermodynamic parameters, as a result relative stability of amino acid molecules change in solution. Amino acid molecules remain as zwitterion in aqueous DMF solution. Three major types of interaction are main responsible for relative stability of amino acid molecules in solution. These are cavity interaction, dipole-dipole interaction and chemical interaction. These interactions are changed with increasing concentration of DMF in solution. The thermodynamics transfer energetics were measured and presented the results in graphically and explained the practical observations. [ABSTRACT FROM AUTHOR]

The recently developed Ru containing drugs have some significant advantages over contemporary Pt-based agents due to their more sophisticated mechanisms of action, lower toxicity, absence of cross resistance, and broad spectrum of activities. In this review, we discuss the recent noteworthy entries devoted to Ru-based anticancer drugs, their industrial utilization and market value. [ABSTRACT FROM AUTHOR]

With the progress in the information technology and evolution of wireless technologies for next generation communications like Internet of Things (IoT) networks and smart sensor networks, non-orthogonal multiple access (NOMA) has emerged as a leading multiple access scheme for connecting these devices. IoT devices are low-powered, designed to stay connected for a more extended period without a frequent recharge, and need reliable connection. NOMA with cooperative relay is considered as a promising technique to connect these devices. In this paper, we analyse the outage performance of a two-hop decode-and-forward relay-assisted signal transmission between the users and a common destination with NOMA as a multiple access scheme. We have considered uplink NOMA, where users first send message signal to the relay with fixed power. Superposition coding is used to transmit the combined signal over a resource blocks at the transmitter side, while a multi-user detection such as successive interference cancellation technique is used to detect the signal at the relay and next at the destination. The effect of relay selection demonstrated in terms of outage probability of the system. A closed-form expression of outage probability for the considered network is theoretically analysed. The analytical result is validated by simulations and demonstrate that outage performance of the system depends on the transmit SNR of both the user. Serving multiple users in NOMA also degrades the outage performance of the system in higher SNR regime. [ABSTRACT FROM AUTHOR]

Summary: In this paper, a multi‐hop cognitive radio (CR) enabled device‐to‐device (D2D) network is considered to extend the communication from a functional area (FA) to a non‐functional area (NFA). A D2D user utilizes a cellular user (CU) band in the cognitive mode for information transmission while maintaining the service quality of CUs by satisfying a collision constraint. It transmits with full power in overlay mode, while the power is controlled in underlay mode. We derive the outage probability of the considered D2D network. The main challenge in CR communications lies in the system robustness to uncertainties. In this paper, we also show the impact of the noise power uncertainty in a multi‐hop D2D network. The expressions for throughput and energy efficiency are also developed under collision constraint and noise uncertainty. The outage probability, throughput, and energy efficiency are investigated for several network parameters such as collision probability, sensing time, noise uncertainty, etc. It is observed that the collision constraint and noise uncertainty have significant impacts on network performance. A simulation test‐bed is developed in MATLAB, and the results obtained in the simulation are verified with the analytical results. [ABSTRACT FROM AUTHOR]

The performance of an unmanned aerial vehicle (UAV) assisted cooperative cognitive radio (CR) network is studied in this paper. The study is carried out for line-of-sight (LOS) links between UAV and a ground user and UAV aerodynamic power consumption of UAV. The UAV consists of an RF energy harvester and it is also a CR enabled device. It harvests energy from RF signal of source nodes. It rotates periodically over a circular region of interest (CROI) for finding the vacant primary user (PU) band. It uses a PU band to set a link between ground nodes, while the direct links between them suffer from severe fading. The decision about the status of a PU band is made cooperatively. In cooperative sensing, all the sources along with the UAV take sensing decisions and send them to fusion centre (FC). A two stage fusion scheme is proposed to take the overall decision. The considered network model uses non-orthogonal multiple access (NOMA) scheme to forward the information of a source to its corresponding destination. Analytical expressions of harvested energy, overall sensing decision and throughput are developed. The analytical expressions capture the effect of fading as well as change in distances (source-UAV and UAV-destination) due to the circular flight of the UAV. Impact of imperfect successive interference cancellation (SIC) on the system performance is also studied. Power allocation in the second hop link is optimized to maximize the network throughput. Energy-efficiency of the considered network is evaluated. For a given UAV flight period, radius of the circular trajectory, and the velocity of the UAV is optimized to maximize the energy-efficiency. Sensing performance of the considered system model is studied in terms of false alarm. Network throughput is investigated for several network parameters such as fading parameter, the number of sources, the number of UAV's sensing slots, the velocity of UAV, the radius of the UAV trajectory etc. Sensing angle and harvesting angle are optimized to maximize the throughput. Results show that the value of fading parameter, radius of UAV trajectory, and UAV velocity has significant impact on throughput. The performance of NOMA is compared with orthogonal multiple access (OMA). [ABSTRACT FROM AUTHOR]

The paper reports the performance of an energy harvesting cognitive radio network under primary user emulation (PUE) attack. A secondary user (SU) can harvest energy from both non-RF (wind, temperature, solar, etc.) and RF sources (RF signal of primary user (PU) and PUE attacker). RF signal harvesting is completely reliant on sensing decisions. A SU accesses the PU channel following a hybrid access scheme. Analytical formulations for SU's harvested energy, channel capacity, and throughput are derived based on the considered network scenario. It is found that there is a considerable effect of PUE attack on harvesting as well as on the network performance. Rewarded energy, channel capacity, and throughput are used to evaluate the network's performance. [ABSTRACT FROM AUTHOR]

In this paper, we analyse the performance of partial relay selection (PRS) for non orthogonal multiple access (NOMA) dual hop relay assisted network, where a source (S) node transmits two signals to respective two destinations (D 1 , D 2) with help of relays. All the relays are powered by harvested energy from RF signal of source. The performance of network is analysed for both signals S 1 and S 2 . The availability of channel state information (CSI) knowledge effects the outage probabilities of both the symbols. We derive closed form expressions of outage probability for both the symbols. Further, we use monte carlo simulation to evaluate ergodic capacity and throughput. The impact of power allocation between both the signals on outage probability is also depicted and a feasible region of power allocation factor between symbols is obtained where NOMA is fairly working. [ABSTRACT FROM AUTHOR]

Utilization of unlicensed spectrum under licensed assisted access ensuring fair co-existence with Wi-Fi networks is a good solution to address immense usage of mobile data. Radio communication operation of LTE in unlicensed frequency band is referred as LTE-unlicensed (LTE-U) or LTE-licensed assisted access. In this paper, we consider a HGNW in which coverage area of Wireless-Fidelity (Wi-Fi)'s Access Point is integrated within the LTE-U small base station's cellular network coverage area. To overcome the disadvantages of existing LTE-U technics like carrier sense adaptive transmission and listen before talk, we proposed a new methodology i.e., sense before transmit in this paper by adopting a transmit power control mechanisms using reciprocity theorem based on the channel state information to assign the secondary carriers in the uplink as well as in the downlink directions in the unlicensed spectrum to carry the traffic. In our proposal, LTE-U users are allowed to use the unlicensed spectrum provided that the interference produced at Wi-Fi users due to LTE-U activities is remained below a certain threshold. We evaluated the performance of proposed network model in terms of outage probability and achievable throughputs. [ABSTRACT FROM AUTHOR]

The thermodynamics of solute–solvent interactions associated with solvation phenomena were estimated for solutions of glycine, DL-alanine, DL-norvaline and DL-serine. Initially, Gibbs free energies of transfer from water to water-sodium iodide mixtures were determined from solubility data. The equilibrium solubilities of amino acids in water and aqueous sodium iodide solution at standard temperature T = 298.15 K were evaluated via formol titration. Various important physicochemical factors like enthalpy, free energy, molar volume, molar mass, etc. in aqueous sodium iodide solution were measured at standard temperature. The thermodynamic parameters were used to analyze the virtual stability of the zwitterionic solutes in aqueous sodium iodide solution. The factors associated with solubility were also explained and interrelated with physical and thermodynamic aspects. [ABSTRACT FROM AUTHOR]

Sodium 3‐amino‐2‐hydroxyanthraquinone‐1‐sulphonate (AQS) is an analogue of the anthracycline based chemotherapeutic drugs that was prepared as a part of the reported study. As the surfactant micelles mimics the biological membrane the present study comprises the interaction of AQS with an anionic surfactant, sodium dodecyl sulfate (SDS) in aqueous media at pH 7.4 which was monitored by using UV–Visible spectroscopy. The aim of the study is to see whether the present molecule penetrates a biological membrane. Different binding parameters like binding constant, partition coefficient, and corresponding Gibbs free energies of the interaction of AQS and its distribution between aqueous media and SDS micelles were measured. The study revealed that hydrophobic interactions play the most important role in binding of AQS to SDS micelles. To see whether AQS really permeates a biological membrane and induces apoptosis, it was allowed to interact with A549 human lung cancer cells. This study established the fact that AQS results apoptosis by means of nucleation into this cell. [ABSTRACT FROM AUTHOR]

The main aim of this paper is to establish the concepts of soft seminorm and soft norm with the help of balanced, absorbing and convex soft sets. Also, we have established equivalent concepts of soft seminorm as well as of soft norm. [ABSTRACT FROM AUTHOR]

Inter-system handover is important for 4G/5G networks as these heterogeneous wireless networks (HWNs) have integrated different radio access technologies with diverse levels of performance. One of the major challenges is to make cell reselection and handover between these technologies. In this paper, we considered convergence of HWNs such as an integrated 3rd generation partnership project long term evaluation with legacy networks like WCDMA, GSM and a wireless local area network. We propose inter-radio access technology hand off or inter-system handoff (ISHO) algorithms to evaluate the performance of integrated network model. Three different realistic handoff scenarios have been investigated in the proposed integrated HWN. The aim of this paper is to evaluate the inter-system handover performance for the network model proposed. The performance of our proposed network model has been carried out using proposed ISHO-algorithms in terms of the average number of handoffs and decision delay. To reduce the unnecessary handoffs, to stave off the ping-pong effect and to lessen the decision delay, additional parameters such as time to trigger and hysteresis values are considered. [ABSTRACT FROM AUTHOR]

In this paper, we consider a multi-hop device-to-device (D2D) communication, which enables communication from functional area (FA), where the D2D users are placed near to base station (BS) under its coverage to non-functional area (NFA). In our proposed model, random deployment as well as certain distance-dependent deployment of D2D node is considered in NFA. In case of FA, BS is transmitting information with fixed transmit power in multi-hop D2D network. In case of NFA, a D2D node harvests energy from its preceding node, and forwards the information to the successive node. Parallel best path selection (PBPS) and immediate best path selection (IBPS) strategies are considered for FA while several cases of deployment strategies based on inter-node distance is considered for NFA to reach the final destination node. A framework has been proposed for evaluating throughput, ergodic capacity and outage probability. Energy consumption in the system has been estimated via simulation. The throughput performance, ergodic capacity and the outage probability of end-to-end link (i.e. from BS to NFA) under different system parameters are evaluated. [ABSTRACT FROM AUTHOR]

In this paper, we will see that the Cartesian product of two 2-Banach spaces is also 2-Banach space and discuss some properties of closed linear opera- tor in linear 2-normed space. We also describe the concept of different types of continuity of b-linear functional and derive the Uniform Boundedness Principle and Hahn-Banach extension theorem for b-linear functionals in the case of linear 2-normed spaces. We also introduce the notion of weak * convergence for the se- quence of bounded b-linear functionals relative to linear 2-normed space. [ABSTRACT FROM AUTHOR]

A simple an expeditious method was established for the synthesis of 2-Substituted-1H-Benzimidazole derivatives at 90oC using o-phenylenediamine and different aldehydes. It has been found that a mixture of Methanesulphonic acid-SiO2 to be an effective catalyst to generate moderate to high yield of a wide variety of 2-substituted benzimidazole derivatives through a simple workup process. Solid phase, rapid reaction, solvent free technique and simplicity of the reaction procedure are the advantages of this protocol. [ABSTRACT FROM AUTHOR]

Cognitive radio is an empowering innovation that guarantees to achieve spectrum utilization. To manage the muddled wireless condition, cooperative spectrum sensing (CSS) has been proposed to make use of the assorted variety in cognitive radio networks (CRNs). However, due to the simplicity of CRNs, CSS are vulnerable to security threats. Spectrum sensing data falsification (SSDF) attacker is one of the attackers in CSS. In the SSDF attack, malicious secondary users (MSUs) send false sensing decisions to the fusion center, which significantly degrades detection accuracy. In this paper, to identify MSUs, a modified delivery based scheme is proposed, where a minimum number of samples are considering for sensing. The proposed security scheme is shown to successfully alleviate the impact of MSUs on global decision making, which enhances the achievable throughput of an honest secondary user. [ABSTRACT FROM AUTHOR]

Multifunctional materials having simultaneous electrical and magnetic assembling have been attempted by numerous researchers for next-generation electronic appliances. Among such materials, rare earth metals containing double perovskites, such as La2BB′O6 (B = Ni, B′ = Mn) are the utmost studied materials. In this review, we have summarized various physicochemical aspects of La2NiMnO6 such as crystal structure, electrical, magnetic, and magneto-transport behavior from earlier studies under several experimental conditions. Magnetic field and temperature effects on magnetoelectric and electronic behavior of this material are described. We discuss how the morphology in the form of bulk phase, thin layer, and nanoparticles affect such physicochemical properties of this material. We also highlighted the role of cation order–disorder at 'B' sites and the probability of the resulting numerous electronic behavior in this type of material and expectation on basic understanding of Ni–O–Mn electronic, as well as magnetic properties. The prospective applications of this material over conventional substances in solar cells, electric tunable devices, biomolecular and gas sensing technologies are also ascribed. The motivation of the present review is to sum up all such behaviors of La2NiMnO6 to find its possible applications in new areas of material research and the directions of future works. Highlights: La2NiMnO6 double perovskite exhibits simultaneous electric and magnetic orderings Crystal structure, magneto-electric, and transport nature affect the functionality of La2NiMnO6 Bulk phase, thin layer, and nanoparticles morphology affect the physical property of La2NiMnO6 La2NiMnO6 holds solar cell, electric tunable device, biomolecular and gas sensing applications [ABSTRACT FROM AUTHOR]

In this paper, we analyze the secrecy outage probability (SOP) of a cognitive cooperative radio network in a two-way communication in which two secondary source communicate with each other via multiple untrusted half-duplex amplify and forward relays in the absence of direct link. Due to the cognitive scenario, power is allocated to secondary nodes on the basis of outage constraint of the primary network. In the absence of direct link between two sources, communication completes in two time slots. In the first time slot, both of the sources broadcast the information signal and in the second time slot, a selected relay broadcasts the amplified information signals of both of the sources. Relays being untrusted, they can eavesdrop the message from the information signal. A particular relay, which maximizes the end-to-end secrecy capacity, is selected to broadcast the signal. The selected untrusted relay can only eavesdrop the message and other relays forcefully remain in idle condition. At the untrusted relay, information signals of both of the sources act as a jamming to each other. The selected untrusted relay harvests the energy using a power splitting ratio scheme. We observe the performance of the proposed model in terms of SOP. We find the optimal values of energy harvesting factor at which SOP becomes minimum. Several important parameters such as the impact of number of untrusted relays, primary transmit power, peak transmit power of secondary sources, threshold outage rate of primary receiver and threshold secrecy rate on SOP is indicated. An analytical expression for the SOP has been developed in a single integration form. Numerical results based on analytical expression are verified by MATLAB simulation. [ABSTRACT FROM AUTHOR]

In this paper, we evaluate the secrecy outage performance and throughput of a hybrid cognitive radio network, where a secondary user (SU) accesses the primary spectrum either in underlay or overlay mode based on spectrum sensing decision. In underlay, the transmit power of the SU as well as the relay is limited by the maximum acceptable interference at primary user (PU) receiver as required by an PU outage constraint, a quality of service for PU. The secondary network employs a decode and forward relay which harvests energy from the radio frequency signal of SU following a time switching relaying protocol. We develop analytical expressions for secrecy outage considering the impact of sensing decision and sensing time. Impact of sensing time, imperfect channel state information of interfering link, energy harvesting time, acceptable interference threshold and PU outage constraint on the secrecy outage probability, as well as throughput of SU are investigated. Further, an interplay between throughput performance and secrecy outage of the network is highlighted. [ABSTRACT FROM AUTHOR]

Physical layer security in relay based cooperative networks is a promising approach to maintain confidentiality of information. In this paper, secrecy performance of a dual hop network, with multiple energy harvesting decode and forward (DF) relays, has been analyzed where an eavesdropper also receives the information from the transmission of a selected relay. A selected DF relay harvests energy based on power splitting (PS) scheme in the first time slot. In the second time slot, the selected DF relay transmits the information as well as jamming signals, only when it has harvested sufficient power as decided by a threshold, based on the outage constraint of the network. The secrecy outage probability (SOP) under some assumed conditions, termed as a conditional SOP (CSOP), has been evaluated in closed form. Performance regarding the CSOP increases with increase in transmits power of the source, threshold outage rate, number of relay and energy conversion efficiency, whereas it decreases with an increase in threshold secrecy rate. We indicate the optimal value of PS factor for harvesting energy and the optimal value of a fraction of harvested energy devoted to information signal transmission at which the CSOP is minimum. The SOP without any condition has also been evaluated with and without jamming. The results shows that the CSOP yields better results than the SOP. It is observed that the CSOP with jamming is better than the SOP with jamming by 49.12% for 1 bits/s/Hz threshold secrecy rate and by 81.94% for a threshold secrecy rate of 0.5 bits/s/Hz, respectively at 10 dBW of the source transmits power. A MATLAB based simulation is used to verify our analytical works of the CSOP and the SOP with jamming. [ABSTRACT FROM AUTHOR]

This paper studies the achievable total throughput of an energy harvesting cooperative cognitive radio (CR) network. A CR transmitter cooperates with a primary user (PU) transmission if PU is found to be present in the given channel while it transmits its own data in the absence of PU. The CR transmitter is an energy harvesting node which harvests simultaneously from non-RF signal as well as RF signal of PU. The CR transmitter uses the harvested energy on shared basis for cooperation and transmission. The same study is also extended for cooperation of multiple CRs in multiple PU band scenario. In cooperation in muti-band scenario, all CRs sense all PU channels and sensing informations are fused at fusion centre to know about the status of PU. Performance is investigated in terms of total network throughput for several parameters such as sensing time, energy splitting parameter, and energy allocation ratio etc. Novel analytical expressions for total useful throughput and optimal energy allocation ratio parameter under the considered network scenario are developed. Useful throughput and optimal energy allocation ratio parameter are also estimated for a target secondary network (CR network) throughput under a quality of service constraint of PU such as collision probability. It is observed that the value of optimal energy allocation parameter gets reduced if the number of CRs in cooperation increases or the number of PU channels increases. [ABSTRACT FROM AUTHOR]

Cooperative spectrum sensing (CSS) is an efficient method to detect vacant spectrum of a primary user (PU) by combining sensing information of multiple cognitive radios (CRs) in presence of fading. In this paper, effects of perfect and imperfect channel state information (CSI) on CSS network is evaluated. The proposed network is operated over Nakagami-q (Hoyt) and Nakagami-n (Rician) fading affecting both reporting (R) and sensing (S) channels. The CRs which employ energy detectors (EDs) are selected on the basis of CSI between them and a fusion center (FC). The knowledge on the quality of R-channels is estimated at FC using a channel estimator. The estimated CSI is either perfect when there is no error in the estimator, or imperfect when errors are present. Accordingly, CRs are selected under both perfect CSI and imperfect CSI cases. All CRs use the decision statistics obtained by EDs and make one-bit binary decisions about the availability of a PU. Selected CRs only transmit decision information to the FC. The miss detection probability and error rate of network under two cases of selection are evaluated by operating majority and maximal ratio combining rules at the FC. Performance is analyzed for different channel and network parameters and comparison between fusion rules for different fading channels is also highlighted. [ABSTRACT FROM AUTHOR]

Femtocell deployment is an important strategy when it comes to improvement of QoS metrics in areas of poor cell coverage like indoors in an LTE environment. This, however, is accompanied by bottlenecks in resource allocation and trade-offs in accuracy for interference management in the heterogeneous two-tier network of macro and femtocell environment. To that end, we propose two schemes using radial division of cells that allocate sub-bands to both femtocell users and macrocell users which in turn, mitigates co-channel interference. Simulation results show that our proposed schemes, commonly named as radial sub-band allocation (RSA-1 and RSA-2) improve performance as measured by signal to interference and noise ratio, sum throughput, outage probability, and channel reuse efficiency while maintaining a balance in computational complexity with existing schemes like F-ALOHA. Further experimentation revealed that the proposed version also works exceedingly well in ultra-dense environments. [ABSTRACT FROM AUTHOR]

For data frame transmissions in beacon‐enabled mode, an IEEE 802.15.4 node performs two consecutive clear channel assessments (CCAs) to sense the channel after back off. Here, the authors study what would happen if the medium access control (MAC) layer performs only one CCA instead. Although it is apparent that the frame transmission cycle would be shortened with single CCA, it is not straightforward to assess the effect of single CCA on the overall transmission energy. A Markov chain‐based MAC operation model is therefore constructed to analyse single‐CCA‐based MAC layer parameters. A combined physical (PHY) and MAC layer energy model is formulated next. It was found that the single CCA‐based MAC outperforms its standard double CCA‐based counterpart from the energy efficiency perspective. [ABSTRACT FROM AUTHOR]

In this paper, a comparative study of parallel best path selection (PBPS) and immediate best path selection IBPS in terms of outage probability and throughput has been done in a multi hop cognitive radio network. The closed form expressions for the outage probability of secondary network in PBPS protocol as well as IBPS protocol in multihop scenario have been derived. We also find the impact of the number of parallel paths in multihop scenario on the outage probability and throughput of secondary network. The performance of PBPS scheme is compared with IBPS scheme. An optimum value of initial harvesting time for secondary nodes (τ) to achieve maximum throughput is also found for both the path selection schemes. [ABSTRACT FROM AUTHOR]

In this paper, the impact of a multi slot based cooperative spectrum sensing (CSS) on the performance of a cognitive radio (CR) network has been investigated. Each CR user, equipped with an improved energy detector (IED), uses a number of mini slots of the sensing time to perform the spectrum sensing. Each CR uses OR logic to combine the sub local decisions generated in each mini slot to obtain a local decision at CR level. Local decisions are sent to fusion centre (FC) over reporting channel. The FC obtains a final decision about the presence of primary user (PU) by combining the local decisions using a fusion rule: Majority or Maximal Ratio Combining. The performance of the CSS is assessed in terms of detection probability and false alarm probability considering both the sensing and reporting channels are Rayleigh faded. Furthermore, the impact of a number of sensing slots and IED parameter on throughput of CR network is also evaluated under the proposed spectrum sensing scenario. Impacts of several sensing parameters such as sensing channel SNR and reporting channel SNR on the performance of CR network are also evaluated. Performances of two fusion rules under study are compared. Effect of sensing error and synchronisation error is indicated. Further the study is extended for independent but non identically distributed (i.n.i.d.) Rayleigh faded channels as well as for a multiple PU scenario also. [ABSTRACT FROM AUTHOR]

In this paper, we examine the physical (PHY) layer security in terms of secrecy outage of an energy harvesting (EH) relay based underlay cognitive radio network (CRN) in the presence of an eavesdropper. A dual hop communication network consisting of an energy harvesting relay that harvests energy from radio transmission of secondary user (SU) network using a time switching relay (TSR) scheme is studied. The relay works in decode and forward (DF) mode and forwards the confidential message to the destination, if it is successfully decoded at the relay. The advantage of the direct link between source to destination is exploited, if the relay link is in outage. Furthermore, simultaneous transmission of message signal and jamming signal to the legitimate nodes and illegitimate node respectively degrades the eavesdropping link capacity. We evaluate the secrecy outage probability (SOP) of the network under study. It is found that exploiting the direct link at the destination increases the secrecy in transmission as compared to the case of only relay based transmission without direct link. The impact of interference threshold, energy harvesting time, power allocation factor, target data rate, target secrecy rate and direct link on SOP of this proposed network is investigated. [ABSTRACT FROM AUTHOR]

Summary: This paper evaluates the performance of an underlay cognitive relay network under imperfect channel state information (CSI) where a secondary user (SU) transmits using a secondary relay (SR) based on decode and forward scheme. The outage probability (OP) of SU is investigated in a scenario where the decode and forward relay harvests energy from radio frequency signal of SU. The relay uses a fraction of time for harvesting in time switching–based relaying (TSR) while a fraction of received power is used for harvesting in power splitting–based relaying (PSR) scheme. The SU and relay control their transmit power using a scaling factor, based on CSI of the interfering links (ie, links from SU transmitter and SR to the primary user [PU] receiver) to protect the quality of service of PU. The available CSI at the SU and SR are imperfect due to practical limitation. Analytical expressions of the OP are derived for TSR‐ and PSR‐based schemes. The impact of harvesting time, power splitting ratio, imperfect CSI, PU outage constraint and interference threshold on the OP of the SU network, and average transmit power of SR is indicated. Further, the impact of multiple SRs is also shown. [ABSTRACT FROM AUTHOR]