A Novel Approach to Reliable Message Broadcasting in Vehicular Ad hoc Networks by Prioritizing both Messages and Density Based Regions

Vehicular Ad hoc Networks (VANETs) are an outgrowth of traditional Mobile Ad hoc Networks (MANETs). VANET is mainly used to model communication in a Vehicular environment where the vehicles are considered as VANET nodes with wireless links. It enables the communications among vehicles and between vehicles and Road Side Units (RSU). In Peer-to-Peer communication, a vehicle can send message to any other vehicle in the network. In doing so, if the destination vehicle is farthest from the source vehicle, then propagation delay is more for the delivery of messages. For a better delivery ratio and to reduce broadcast storms, a message has to be relayed through intermediate nodes known as representative nodes (RN)s to the destination. The main requirement of VANET is location information. Using Greedy Forward algorithm, messages to farthest nodes are transmitted by computing RNs. Though we communicate with the farthest node through representative nodes, due to the special characteristics of VANETs such as high mobility, unstable links or dynamic nature of vehicles, representative nodes positions are to be computed dynamically. If the information about the high density region and low density region are gathered then the problems that arise with sparse VANETs also can be minimized. Otherwise the prior approach sends information to low density region continuously than high density regions. This problem can be minimized if we apply DBSCAN algorithm to form clusters (regions) using location information, then high density regions can be given highest priority for message transmission. As VANETs main characteristic is urgent message transmission, the messages are to be prioritized and then transmitted over the network. In this paper, Greedy forward approach and DBSCAN algorithms are pipelined to increase the performance of broadcasting messages over the VANET. In addition to this, in this paper, we also prioritize the messages for urgent message transmission over the VANET. This provides hybrid solution to the lossless instant messaging mechanism as this works on real time environment. Keywords: VANET, Representative Node (RN), Road Side Unit (RSU), Global Positioning System (GPS),Greedy Perimeter Stateless Routing (GPSR) , DBSCAN (Density Based Spatial Clustering of Applications with Noise)

Production and quantification of Asiatic acid from in vitro raised shoots and callus cultures of Centella asiatica (L.) Urban

Abstract Centella asiatica (L.) Urban, is one of the important medicinal plants, belonging to the family Apiaceae, with a range of medicinal values. The secondary metabolites produced by Centella asiatica are of ursane type and are called as "Centellosides". Asiatic acid is one of the important bioactive compounds produced by the plant, having several medicinal properties. The present study is an attempt towards the production of asiatic acid in the in vitro grown shoots as well as callus. In vitro grown shoots in semisolid and liquid media produced 1.02± 0.03 mg/gFW and 0.47± 0.08 mg/gFW asiatic acid, respectively, whereas leaf callus produced a maximum amount of 1.46± 0.06 mg/gFW asiatic acid

Protection of “Fault Tolerant Parallel Filters” by Hamming code with Reversible logic

Digital filters are widely used in signal processing and communication systems. In some cases, the reliability of those systems is critical, and fault tolerant filter implementations are needed. Over the years, many techniques that exploit the filters’ structure and properties to achieve fault tolerance have been proposed. As technology scales, it enables more complex systems that incorporate many filters. In those complex systems, it is common that some of the filters operate in parallel, for example, by applying the same filter to different input signals. . The complexity occurs while decoding the received encoded data. More often the transmitted data is subjected to the channel noise which influences the original signal. To overcome this problem many error correction codes (ECC’s) are introduced.Recently, a simple technique that exploits the presence of parallel filters to achieve fault tolerance has been presented In this paper we proposed an error detection and correction code called hamming code. The hamming code not only detects the errors as conventional codes but also it is able to correct the data. In addition the process is supported with  reversible gate logic. This is the updated design methodology to reduce the power consumption and complexity. Reversible computing will also lead to improvement in energy efficiency. Energy efficiency will fundamentally affect the speed of circuits such as nano-circuits and therefore the speed of most computing applications. To increase the portability of devices again reversible computing is required. This idea is generalized to show that parallel filters can be protected using error correction codes (ECCs) in which each filter is the equivalent of a bit in a traditional ECC. This new scheme allows more efficient protection when the number of parallel filters is large. The technique is evaluated using a case study of parallel finite impulse response filters showing the effectiveness in terms of protection and implementation cost

Emerging Copper-Based Semiconducting Materials for Photocathodic Applications in Solar Driven Water Splitting

Hydrogen production through solar-driven water splitting is a promising approach and an alternative to the conventional steam reforming of natural gas and coal gasification. The growing energy demand and environmental degradation through carbon-emitting fossil fuels urge a transition in the usage of non-renewable to renewable sources of energy. The photocathodes in a photoelectrochemical (PEC) water-splitting cell are essential for the direct evolution of hydrogen. Among the known photocathodes, Cu-based p-type semiconducting materials are the most promising photo-absorber materials owing to their low-cost, low toxicity, natural abundance, suitable bandgaps, and favorable band edges for reduction. Moreover, the chemical stability and the rate of recombination significantly limit the longevity, the PEC performance, and practical applicability of Cu-based photocathodes. To overcome these problems, it is critical to have a thorough understanding of the constraints, improvement strategies, and an assessment of current developments in order to construct and design highly stable and efficient photocathodes. Here, in this review we have summarized the development of Cu-based metal oxide and sulfide photocathodes with the significant operational challenges and strategies that have successfully been employed to enhance the PEC performance. Furthermore, the emphasis is placed on recent reports and future perspectives regarding emerging challenges

Recent trends in photoelectrochemical water splitting: the role of cocatalysts

Environmental degradation due to the carbon emissions from burning fossil fuels has triggered the need for sustainable and renewable energy. Hydrogen has the potential to meet the global energy requirement due to its high energy density; moreover, it is also clean burning. Photoelectrochemical (PEC) water splitting is a method that generates hydrogen from water by using solar radiation. Despite the advantages of PEC water splitting, its applications are limited by poor efficiency due to the recombination of charge carriers, high overpotential, and sluggish reaction kinetics. The synergistic effect of using different strategies with cocatalyst decoration is promising to enhance efficiency and stability. Transition metal-based cocatalysts are known to improve PEC efficiency by reducing the barrier to charge transfer. Recent developments in novel cocatalyst design have led to significant advances in the fundamental understanding of improved reaction kinetics and the mechanism of hydrogen evolution. To highlight key important advances in the understanding of surface reactions, this review provides a detailed outline of very recent reports on novel PEC system design engineering with cocatalysts. More importantly, the role of cocatalysts in surface passivation and photovoltage, and photocurrent enhancement are highlighted. Finally, some challenges and potential opportunities for designing efficient cocatalysts are discussed

Mn-doped ZnO microspheres prepared by solution combustion synthesis for room temperature NH3 sensing

Despite being the most favorable ammonia (NH3) gas sensors, metal oxide semiconductors fail to deliver high selectivity and room temperature (RT) sensing. Tuning the metal oxide with doping is an attractive way of overcoming these disadvantages. Herein, we report Mn-doped ZnO microspheres as promising sensors for highly sensitive and selective RT sensing of NH3. ZnO and 2 wt% Mn-doped ZnO microspheres were synthesized by a low-cost and fast solution combustion synthesis, and their structure, morphology, and gas sensing properties were investigated. Mn-doping resulted in a change in the lattice parameters, an increase in the oxygen vacancies, and surface acidity of ZnO as confirmed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Temperature programmed desorption (TPD), respectively. Mn-doped ZnO showed a response (Ra/Rg) of 20.2 in 100 ppm NH3, which is significantly higher than ZnO. The sensor showed high selectivity, three times higher than that of ZnO, and good stability. Improvement in the sensing performance of Mn-doped ZnO is attributed to the increase in the defects and surface acidity with Mn-doping. © 2022 The Author(s

Integrated p-n Junctions for Efficient Solar Water Splitting upon TiO2/CdS/BiSbS3 Ternary Hybrids for Improved Hydrogen Evolution and Mechanistic Insights

The development of efficient and novel p-n heterojunctions for photoelectrochemical (PEC) water splitting is still a challenging problem. We have demonstrated the complementary nature of (p-type) BiSbS3 as a sensitizer when coupled with (n-type) TiO2/CdS to improve the photocatalytic activity and solar to hydrogen conversion efficiency. The as-prepared p-n heterojunction TiO2/CdS/BiSbS3 exhibits good visible light harvesting capacity and high charge separation over the binary heterojunction, which are confirmed by photoluminescence (PL) and electrical impedance spectroscopy (EIS). The ternary heterojunction produces higher H-2 than the binary systems TiO2/CdS and TiO2/BiSbS3. This ternary heterojunction system displayed the highest photocurrent density of 5 mA center dot cm(-2) at 1.23 V vs. reversible hydrogen electrode (RHE) in neutral conditions, and STH of 3.8% at 0.52 V vs. RHE is observed. The improved photocatalytic response was due to the favorable energy band positions of CdS and BiSbS3. This study highlights the p-n junction made up of TiO2/CdS/BiSbS3, which promises efficient charge formation, separation, and suppression of charge recombination for improved PEC water splitting efficiency. Further, no appreciable loss of activity was observed for the photoanode over 2500 s. Band alignment and interfaces mechanisms have been studied as well

AI is a viable alternative to high throughput screening: a 318-target study

: High throughput screening (HTS) is routinely used to identify bioactive small molecules. This requires physical compounds, which limits coverage of accessible chemical space. Computational approaches combined with vast on-demand chemical libraries can access far greater chemical space, provided that the predictive accuracy is sufficient to identify useful molecules. Through the largest and most diverse virtual HTS campaign reported to date, comprising 318 individual projects, we demonstrate that our AtomNet® convolutional neural network successfully finds novel hits across every major therapeutic area and protein class. We address historical limitations of computational screening by demonstrating success for target proteins without known binders, high-quality X-ray crystal structures, or manual cherry-picking of compounds. We show that the molecules selected by the AtomNet® model are novel drug-like scaffolds rather than minor modifications to known bioactive compounds. Our empirical results suggest that computational methods can substantially replace HTS as the first step of small-molecule drug discovery

TiO2 Photoanodes Sensitized with Bi2Se3 Nanoflowers for Visible–Near-Infrared Photoelectrochemical Water Splitting

Semiconducting photoelectrodes emerge as an efficient platform for converting light energy into hydrogen by photoelectrochemical (PEC) water splitting. The present study reports the improvement in PEC performance using metal oxide photoelectrodes sensitized with a narrow-band-gap semiconductor Bi2Se3, which extends the light response beyond the visible region and generates and transports charge carriers. When Bi2Se3 nanoflowers (NFs) were incorporated into the TiO2 electrode, the extent of hydrogen production was found to be increased by an order of magnitude. The binary electrode TiO2/Bi2Se3 nanocomposite exhibited a decent photocurrent density of 1.76 mA cm-2 at 1.23 V, which is three times superior to that of pure Bi2Se3 NFs. Moreover, the binary TiO2/Bi2Se3 electrode delivers the highest solar-to-hydrogen conversion efficiency of 1.01% at 0.6 V and incident photon-to-current conversion efficiency of 10.5%. Furthermore, both Bi2Se3 and TiO2/Bi2Se3 electrodes show superior photostabilities for over 6 h. The enhanced PEC activity is attributable to the facile transportation of photoelectrons from Bi2Se3 to TiO2 electrodes, thereby minimizing the charge recombination