Anna University, Chennai

This article covers key and representative developments in the area of high efficiency and clean internal combustion engines. The main objective is to highlight recent efforts to improve (IC) engine fuel efficiency and combustion. Rising fuel prices and stringent emission mandates have demanded cleaner combustion and increased fuel efficiency from the IC engine. This need for increased efficiency has placed compression ignition (CI) engines in the forefront compared to spark ignition (SI) engines. However, the relatively high emission of oxides of nitrogen (NOx) and particulate matter (PM) emitted by diesel engines increases their cost and raises environmental barriers that have prevented their widespread use in certain markets. The desire to increase IC engine fuel efficiency while simultaneously meeting emissions mandates has thus motivated considerable research. This paper describes recent progress to improve the fuel efficiency of diesel or CI engines through advanced combustion and fuels research. In particular, a dual fuel engine combustion technology called “reactivity controlled compression ignition” (RCCI), which is a variant of Homogeneous Charge Compression Ignition (HCCI), is highlighted, since it provides more efficient control over the combustion process and has the capability to lower fuel use and pollutant emissions. This paper reviews recent RCCI experiments and computational studies performed on light- and heavy-duty engines, and compares results using conventional and alternative fuels (natural gas, ethanol, and biodiesel) with conventional diesel, advanced diesel and HCCI concepts.

This paper reviews methods to fix a number of hidden neurons in neural networks for the past 20 years. And it also proposes a new method to fix the hidden neurons in Elman networks for wind speed prediction in renewable energy systems. The random selection of a number of hidden neurons might cause either overfitting or underfitting problems. This paper proposes the solution of these problems. To fix hidden neurons, 101 various criteria are tested based on the statistical errors. The results show that proposed model improves the accuracy and minimal error. The perfect design of the neural network based on the selection criteria is substantiated using convergence theorem. To verify the effectiveness of the model, simulations were conducted on real-time wind data. The experimental results show that with minimum errors the proposed approach can be used for wind speed prediction. The survey has been made for the fixation of hidden neurons in neural networks. The proposed model is simple, with minimal error, and efficient for fixation of hidden neurons in Elman networks.

Graphene oxide, like graphite oxide, is often described as an electrical insulator, due to the disruption of its sp 2 bonding networks. In actuality, this is not entirely true. The ability for graphene oxide

The electronic structure and ground state properties of ${\mathrm{AlB}}_{2}$ type transition metal diborides ${\mathrm{TMB}}_{2}$ (TM=Sc, Ti, V, Cr, Mn, Fe, Y, Zr, Nb, Mo, Hf, Ta) have been calculated using the self consistent tight-binding linear muffin-tin orbital method. The equilibrium volume, bulk moduli ${(B}_{0}),$ pressure derivative of bulk moduli ${(B}_{0}^{\ensuremath{'}}),$ cohesive energy ${(E}_{\mathrm{coh}}),$ heat of formation $(\ensuremath{\Delta}H),$ and electronic specific heat coefficient $(\ensuremath{\gamma})$ are calculated for these systems and compared with the available experimental and other theoretical results. The bonding nature of these diborides is analyzed via the density of states (DOS) histogram as well as the charge density plots, and the chemical stability is analyzed using the band filling principle. The variation in the calculated cohesive properties of these materials is correlated with the band filling effect. The existence of a pseudogap in the total density of states is found to be a common feature for all these compounds. The reason for the creation of the pseudogap is found to be due to the strong covalent interaction between boron p states. We have made spin polarized calculations for ${\mathrm{CrB}}_{2},$ ${\mathrm{MnB}}_{2},$ and ${\mathrm{FeB}}_{2}$ and found that finite magnetic moments exist for ${\mathrm{MnB}}_{2}$ and ${\mathrm{CrB}}_{2}$ whereas ${\mathrm{FeB}}_{2}$ is nonmagnetic.

We present some general techniques for constructing full-rank, minimal-delay, rate at least one space-time block codes (STBCs) over a variety of signal sets for arbitrary number of transmit antennas using commutative division algebras (field extensions) as well as using noncommutative division algebras of the rational field /spl Qopf/ embedded in matrix rings. The first half of the paper deals with constructions using field extensions of /spl Qopf/. Working with cyclotomic field extensions, we construct several families of STBCs over a wide range of signal sets that are of full rank, minimal delay, and rate at least one appropriate for any number of transmit antennas. We study the coding gain and capacity of these codes. Using transcendental extensions we construct arbitrary rate codes that are full rank for arbitrary number of antennas. We also present a method of constructing STBCs using noncyclotomic field extensions. In the later half of the paper, we discuss two ways of embedding noncommutative division algebras into matrices: left regular representation, and representation over maximal cyclic subfields. The 4/spl times/4 real orthogonal design is obtained by the left regular representation of quaternions. Alamouti's (1998) code is just a special case of the construction using representation over maximal cyclic subfields and we observe certain algebraic uniqueness characteristics of it. Also, we discuss a general principle for constructing cyclic division algebras using the nth root of a transcendental element and study the capacity of the STBCs obtained from this construction. Another family of cyclic division algebras discovered by Brauer (1933) is discussed and several examples of STBCs derived from each of these constructions are presented.

The second-generation hybrid and Electric Vehicles are currently leading the paradigm shift in the automobile industry, replacing conventional diesel and gasoline-powered vehicles. The Battery Management System is crucial in these electric vehicles and also essential for renewable energy storage systems. This review paper focuses on batteries and addresses concerns, difficulties, and solutions associated with them. It explores key technologies of Battery Management System, including battery modeling, state estimation, and battery charging. A thorough analysis of numerous battery models, including electric, thermal, and electro-thermal models, is provided in the article. Additionally, it surveys battery state estimations for a charge and health. Furthermore, the different battery charging approaches and optimization methods are discussed. The Battery Management System performs a wide range of tasks, including as monitoring voltage and current, estimating charge and discharge, equalizing and protecting the battery, managing temperature conditions, and managing battery data. It also looks at various cell balancing circuit types, current and voltage stressors, control reliability, power loss, efficiency, as well as their advantages and disadvantages. The paper also discusses research gaps in battery management systems.

The composite manufacturing has been a wide area of research and it is the preferred choice due to its superior properties like low density, stiffness, light weight and possesses better mechanical properties. This has found its wide applications in aerospace, automotive, marine and sporting industries. There has been continuous lookout for synthesizing composites without compromising on the mechanical and physical properties. In this research, fiber reinforced composites were prepared with jute fibers of fiber length 5-6 mm. The resins used in this study are polyester and epoxy. The composites were synthesized at 18:82 fiber-resin weight percentages. The prepared composites were tested to study the mechanical properties of the composite such as tensile strength, flexural strength, impact strength and hardness. The results show that the jute reinforced epoxy composite exhibited better mechanical properties than Jute-polyester composite.

The computational complexity of approximating omega (G), the size of the largest clique in a graph G, within a given factor is considered. It is shown that if certain approximation procedures exist, then EXPTIME=NEXPTIME and NP=P.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Abstract Geochemical signatures of ground water in a part of Kancheepuram district, Tamil Nadu, India, were used to identify the chemical processes that control hydrogeochemistry. Physical parameters, such as electrical conductivity, pH, and major ion concentrations, such as Ca, Mg, Na, K, Cl, HCO3, CO3, and SO4, of ground water were taken into consideration. Concentrations of these cations and anions in the ground water vary spatially and temporally. Abundance of these ions are in the following order: Ca &amp;gt; Na &amp;gt; Mg &amp;gt; K = HCO3 &amp;gt; Cl &amp;gt; CO3 &amp;gt; SO4. Ca-HCO3 and Ca-Cl-HCO3 are the dominant hydrochemical facies of the study area. Interpretation of hydrochemical data suggests that calcium carbonate dissolution, ion-exchange processes, silicate weathering, and mixing of aerosols are responsible for the ground-water chemistry of the study area. Identified hydrogeochemical processes were verified and quantified using hydrogeochemical inverse mass-balance modeling (net geochemical reactions along a flow path, NETPATH). The models suggest that carbonate dissolution, halite dissolution, Ca/Na ion exchange, and Mg/Na ion exchange are the major processes that control the ground-water chemistry. Gypsum dissolution and illite precipitation/dissolution are also partly responsible for the chemistry of ground water.

Abstract The Green Revolution in India was initiated in the 1960s by introducing high-yielding varieties of rice and wheat to increase food production in order to alleviate hunger and poverty. Post-Green Revolution, the production of wheat and rice doubled due to initiatives of the government, but the production of other food crops such as indigenous rice varieties and millets declined. This led to the loss of distinct indigenous crops from cultivation and also caused extinction. This review deals with the impacts the Green Revolution had on the production of indigenous crops, its effects on society, environment, nutrition intake, and per capita availability of foods, and also the methods that can be implemented to revive the indigenous crops back into cultivation and carry the knowledge to the future generation forward.

clinical trials.Communicated by Ramaswamy H. Sarma.

Bombyx mori L. (Lepidoptera: Bombycidae) have been domesticated and widely used for silk production. It feeds on mulberry leaves. Mulberry leaves are mainly composed of pectin, xylan, cellulose and starch. Some of the digestive enzymes that degrade these carbohydrates might be produced by gut bacteria. Eleven isolates were obtained from the digestive tract of B. mori, including the Gram positive Bacillus circulans and Gram negative Proteus vulgaris, Klebsiella pneumoniae, Escherichia coli, Citrobacter freundii, Serratia liquefaciens, Enterobacter sp., Pseudomonas fluorescens, P. aeruginosa, Aeromonas sp., and Erwinia sp.. Three of these isolates, P. vulgaris, K. pneumoniae, C. freundii, were cellulolytic and xylanolytic, P. fluorescens and Erwinia sp., were pectinolytic and K. pneumoniae degraded starch. Aeromonas sp. was able to utilize the CMcellulose and xylan. S. liquefaciens was able to utilize three polysaccharides including CMcellulose, xylan and pectin. B. circulans was able to utilize all four polysaccharides with different efficacy. The gut of B. mori has an alkaline pH and all of the isolated bacterial strains were found to grow and degrade polysaccharides at alkaline pH. The number of cellulolytic bacteria increases with each instar.

Water resources are crucial in developing any area as they serve as a major source of potable, agricultural, and industrial water. Water contamination, caused by natural and anthropogenic activities, poses a significant threat to public health globally. This review synthesizes data from various studies published in national and international journals, as well as reports from governmental and non-governmental organizations. Our primary objective is to understand and review previous research on water pollution, contamination types, and the effects of water contamination on public health. Water pollution studies generally involve a scientific understanding of the biological, chemical, and physical processes that control the movement of contaminants in the underground environment. The nature and severity of health consequences vary based on several factors, including the chemical composition, duration of exposure, and concentration of pollutants. This work highlights the human health risks associated with current research topics such as anthropogenic, geogenic, microplastics, pharmaceuticals, and heavy metals. A section on remedial measures and mitigation strategies is included to emphasize sustainable approaches to water conservation, replenishment, and sustainability. However, there is a lack of comprehensive knowledge regarding the distribution, toxic effects, and human health risks associated with different sources of contamination. This review thus establishes links between multiple sources of pollution, their toxicity to human health, and approaches to health risk assessment.

The adsorption of lysozyme on the mesoporous molecular sieves MCM-41 and SBA-15 from buffered solutions with different pH values has been studied as a model protein adsorption system. The amount adsorbed depends on the solution pH as well as on the pore volume and the composition of the adsorbent. The adsorption isotherms at pH 6.5 to 10.5 fitted the Langmuir model (type L isotherm), while the isotherms recorded at pH 12 are of the S type. The maximum amount adsorbed was observed for AlSBA-15 at pH 9.6 and amounted to 47.2 μmol/g (580 mg/g). The stability of SBA-15 toward to the buffer solution is higher for SBA-15 as compared to MCM-41, which is probably a consequence of the higher wall thickness of the former material. Diffuse reflectance Fourier transform infrared spectra of the adsorbed lysozyme confirm that the adsorption of the enzyme did not result in denaturation of Lz.

The adsorption of cytochrome c onto different mesoporous molecular sieves (C12−MCM-41, C16−MCM-41 and SBA-15) is studied at different solution pHs. Adsorption isotherms were recorded up to final solution concentrations of ca. 250 μmol/L and were found to be of the pseudo-Langmuir type. Cytochrome c (cyt c) adsorption was observed to be pH-dependent with maximum adsorption near the isoelectric point of the protein. SBA-15 showed a larger amount of cyt c adsorption as compared to MCM-41. The increased cyt c adsorption capacity may be due to the larger pore volume and pore diameter as compared to C12− and C16−MCM-41. It has been discovered that the amount of cyt c adsorption can be increased by the introduction of aluminum into the pure silica materials. The observed increase is most likely a consequence of the strong electrostatic interaction between the negative charges on the aluminum sites and the positively charged amino acid residues of cyt c. Furthermore, the rate of cyt c adsorption has been studied and no significant differences in adsorption rate were found for the mesoporous materials with different pore diameters between 3 and 9 nm. While the adsorption capacity is reduced upon bead formation (due to the reduction in specific pore volume), the rate of adsorption is mainly unchanged.

cytotoxic effect of biologically synthesized silver and gold nanoparticles against MDA-MB-231, human breast cancer cells. Formation of silver and gold nanoparticles was observed within 30 min and the various characterization techniques such as UV-vis spectrophotometer, FE-SEM, TEM and XRD studies were confirmed the synthesis of nanoparticles. Further, MTT, acridine orange and ethidium bromide (AO/EB) dual staining, caspase-3 and DNA fragmentation assays were carried out using various concentrations of silver and gold nanoparticles ranging from 1 to 100 μg/ml. At 100 μg/ml concentration, the plant extract derived nanoparticles exhibited significant cytotoxic effects and the apoptotic features were confirmed through caspase-3 activation and DNA fragmentation assays. Thus, the results of the present study indicate that biologically synthesized silver and gold nanoparticles might be used to treat breast cancer; however, it necessitates clinical studies to ascertain their potential as anticancer agents.

This paper presents a summary of research work published in the field of banana fiber reinforced polymer composites with special references to the structure, physical and mechanical properties of the composites.

Tetracycline occurrence and advanced treatment techniques.

Vehicular ad hoc networks (VANETs) are an important communication paradigm in modern-day mobile computing for exchanging live messages regarding traffic congestion, weather conditions, road conditions, and targeted location-based advertisements to improve the driving comfort. In such environments, security and intelligent decision making are two important challenges needed to be addressed. In this paper, a trusted authority (TA) is designed to provide a variety of online premium services to customers through VANETs. Therefore, it is important to maintain the confidentiality and authentication of messages exchanged between the TA and the VANET nodes. Hence, we address the security problem by focusing on the scenario where the TA classifies the users into primary, secondary, and unauthorized users. In this paper, first, we present a dual authentication scheme to provide a high level of security in the vehicle side to effectively prevent the unauthorized vehicles entering into the VANET. Second, we propose a dual group key management scheme to efficiently distribute a group key to a group of users and to update such group keys during the users' join and leave operations. The major advantage of the proposed dual key management is that adding/revoking users in the VANET group can be performed in a computationally efficient manner by updating a small amount of information. The results of the proposed dual authentication and key management scheme are computationally efficient compared with all other existing schemes discussed in literature, and the results are promising.

Abstract Rice is a major cereal food crop and staple food in most of the developing countries. India stands second in the production of rice next to China. Though almost 40,000 varieties of rice are said to exist, at present, only a few varieties are cultivated extensively, milled and polished. Even if white rice is consumed by most people around the world, some specialty rice cultivars are also grown. These include the coloured and aromatic rice varieties. The nutritional profile of the specialty rice is high when compared to the white rice varieties. The coloured rice, which usually gets its colour due to the deposition of anthocyanin pigments in the bran layer of the grain, is rich in phytochemicals and antioxidants. Rice bran, a by-product of the rice milling industry is under-utilised, is rich in dietary fibre which finds application in the development of functional foods and various other value-added products. Thus, more focus on specialty rice and its by-products will not only save it from becoming extinct but also lead a step forward towards nutrition security of the country as they are abundant in vitamins, minerals and polyphenols.