Improved Approximation Algorithm for Graph Burning on Trees

Given a graph $G=(V,E)$, the problem of \gb{} is to find a sequence of nodes from $V$, called burning sequence, in order to burn the whole graph. This is a discrete-step process, in each step an unburned vertex is selected as an agent to spread fire to its neighbors by marking it as a burnt node. A node that is burnt spreads the fire to its neighbors at the next consecutive step. The goal is to find the burning sequence of minimum length. The \gb{} problem is NP-Hard for general graphs and even for binary trees. A few approximation results are known, including a $3$-approximation algorithm for general graphs and a $2$- approximation algorithm for trees. In this paper, we propose an approximation algorithm for trees that produces a burning sequence of length at most $\lfloor 1.75b(T) \rfloor + 1$, where $b(T)$ is length of the optimal burning sequence, also called the burning number of the tree $T$. In other words, we achieve an approximation factor of $(\lfloor 1.75b(T) \rfloor + 1)/b(T)$

Study on flame retardant properties of poly(lactic acid) fibre fabrics

Polylactic acid  and its blended yarns with various fibres have been converted in to woven fabrics. These fabric samples have been scoured and then tested for mechanical and flame retardant properties. The results indicate that the high alkaline scouring severely damages polylactic acid fibre. Therefore, mild alkaline scouring is done for further studies. The scoured fabric samples are tested for various flame retardant properties and compared with polyester blended fabrics. Results indicate that polylactic acid fibre is not suitable for upholstery, apparel and work wear in terms of flame retardant properties

Spray deposited copper zinc tin sulphide (Cu<inf>2</inf>ZnSnS<inf>4</inf>) film as a counter electrode in dye sensitized solar cells

Stoichiometric thin films of Cu2ZnSnS4 (CZTS) were deposited by the spray technique on a FTO coated glass substrate, with post-annealing in a H2S environment to improve the film properties. CZTS films were used as a counter electrode (CE) in Dye-Sensitized Solar Cells (DSCs) with N719 dye and an iodine electrolyte. The DSC of 0.25 cm2 area using a CE of CZTS film annealed in a H2S environment under AM 1.5G illumination (100 mW cm-2) exhibited a short circuit current density (JSC) = 18.63 mA cm-2, an open circuit voltage (VOC) = 0.65 V and a fill factor (FF) = 0.53, resulting in an overall power conversion efficiency (PCE) = 6.4%. While the DSC using as deposited CZTS film as a CE showed the PCE = 3.7% with JSC = 13.38 mA cm-2, VOC = 0.57 V and FF = 0.48. Thus, the spray deposited CZTS films can play an important role as a CE in the large area DSC fabrication. © the Partner Organisations 2014

DESIGN AND EVALUATION OF NOVEL TOPICAL GEL OF TINOSPORA CORDIFOLIA AS ANTIMICROBIAL AGENT

Objective: The present study deals with topical formulations of a bioactive extract of Tinospora cordifolia and its evaluation.Methods: Dried, powdered stem was extracted with chloroform using ultra-sonication method for 3 hrs. Topical formulations like gels containingchloroform extract were formulated using various gelling agents. These gels were evaluated for physicochemical parameters, viscosity, spreadaibility,and antimicrobial activity.Results: A topical gel was successfully formulated containing bioactive chloroform extract of T. cordifolia. The gel was very effective as antimicrobialformulations.Conclusion: These kinds of formulations can be very promising wound healing medicines with ease of use and no side effects.Keywords: Topical gel, Tinospora Cordifolia, Anitmictobia

Health-based risk targets for fluorosis in tribal children of rural Madhya Pradesh, India

Conventional approaches to fluorosis mitigation and control are based on reduction of excess fluoride consumption from water. Country specific standard limits of 1 mg/l or 1.5mg/l are established and monitored by water departments based on recommendations outlined in the World Health Organization (WHO) Guidelines for Drinking Water Quality (GDWQ). With the advent of the third edition of the WHO GDWQ there is a fundamental departure from standard setting, based on doseresponse affect, towards risk assessment and risk management. The water quality framework, outlined in the guidelines, consists of an iterative cycle, comprising: an assessment of risk, health targets linked to the wider public health context; risk management (with these components being informed by aspects of environmental exposure and acceptable risk) The guidelines advocate for the use of Water Safety Plans, as risk management tool, to help achieve Health Based Risk Targets. This paper presents the application of a Quantitative Chemical Risk Assessment (QCRA) method for determining health based risk targets for fluorosis control. The paper presents evidence from Madhya Pradesh, India. The findings indicate firstly that to control fluorosis total daily consumption from all exposure routes (water and food) must be considered, secondly that the most exposed population group to fluorosis are children due to lack of alternative early nutrients (e.g. exclusive breastfeeding) and, thirdly, that quantifying chemical risk is essential for appropriate risk management strategies to reduce fluorosis in children

Performance analysis of anomalous photocatalytic activity of Cr-doped TiO2 nanoparticles [Cr(x)TiO2(1-x)]

We report the synthesis and characterisation of pristine and chromium (Cr) metal ion-doped titanium dioxide nanoparticles [Cr(x)TiO2(1-x)] to study the anomalous effect of Cr doping on the photocatalytic property of TiO2. The presence of dopants generates more number of recombination pairs and increases surface coverage sites which decreases photocatalytic activity. We study the structural morphology of the synthesised Cr(x)TiO2(1-x) samples using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy analysis. The effect of Cr3+ ions on the optical properties of TiO2 has been studied using various imaging and spectroscopic techniques. Further, the effect of doping of Cr on the photocatalytic activity of TiO2 has been analysed in detail. The concentration of Cr in TiO2 has been chosen as 0, 1, 5 and 10% by weight. It has been observed that the pristine TiO2 exhibits better photocatalytic activity as compared to Cr-doped TiO2 irrespective of the Cr concentration. This can be attributed to the fact that due to Cr doping in TiO2, the number of available adsorption sites for malachite green reduces which degrades its photocatalytic activity. It is also confirmed by photoluminescence (PL) and time-resolved photoluminescence spectroscopy. PL intensity increases, and lifetime decreases with increase in doping concentration. Radiative recombination of electron and hole pairs of Cr3+ in TiO2 degrades its photocatalytic activity. The degradation efficiency is found to be 96% in the case of pristine TiO2 which reduces to 12% when doped with x = 10% concentration of chromium. Therefore, it is observed that in comparison with Cr-doped TiO2, pristine TiO2 exhibits an improved photocatalytic activity which shows the anomalous effect of Cr doping on the photocatalytic property of TiO2

Evaluation of nutrient management for better growth, yield and economics of fenugreek

A field experiment was conducted to study the effect of nutrient management combinations in fenugreek (Trigonella foenum-graecum). Growth as well as seed and straw yields of fenugreek were significantly influenced by different treatments. Application of recommended dose through inorganic form (50%) + neem cake @ 638 kg ha-1 + Rhizobium melilotii + phosphate solubilising bacteria (PSB) recorded the highest plant height of 34.98 cm, leaves of 82.35 and branches of 5.5 at the final harvest stage. This treatment also recorded significantly highest straw yields. The maximum seed yield, net returns and benefit cost ratio were obtained in the combination of 50% recommended dose of fertilizer (RDF) + poultry manure (PM) @1000 kg ha-1 + Rhizobium melilotii + phosphate solubilising bacteria (PSB). &nbsp

A Sustainable Development Perspective and Evaluating the Impact of Laser Cladding Parameters on Mild Steel

Mild steel is a popular material used in various applications due to its excellent machinability, strength and durability. Mild steel is one of the most affordable materials available, making it an excellent choice for budget-conscious projects. Regrettably, Mild steel is not typically used in some industries due to its low strength-to-weight ratio and limited corrosion resistance. AISI 1020 steel is relatively soft and has limited wear resistance compared to other types of steel, particularly those with higher carbon content. This review paper discusses the profitable and successful approach to enhance the service life and utility of the mild steel machinery components. Various investigators have put their effort into developing different methods to improve the properties of the mild steel components. The laser cladding process is developed by the melting of the preplaced coating layer with the surface of the substrate simultaneously which is able to prevent direct contact with the environment. The present review paper discussed in detail the impact of various parameters of laser cladding process and variation of the coating materials on the surface properties and microstructure of mild steel. Some challenges and remedies are also discussed in the paper. This review paper focused on some potential uses of the laser cladding process in diverse industries

Spray deposited copper zinc tin sulphide (Cu2ZnSnS4) film as a counter electrode in dye sensitized solar cells.

PublishedThis is the author accepted manuscript. The final version is available from the Royal Society of Chemistry via the DOI in this record.Stoichiometric thin films of Cu2ZnSnS4 (CZTS) were deposited by the spray technique on a FTO coated glass substrate, with post-annealing in a H2S environment to improve the film properties. CZTS films were used as a counter electrode (CE) in Dye-Sensitized Solar Cells (DSCs) with N719 dye and an iodine electrolyte. The DSC of 0.25 cm(2) area using a CE of CZTS film annealed in a H2S environment under AM 1.5G illumination (100 mW cm(-2)) exhibited a short circuit current density (JSC) = 18.63 mA cm(-2), an open circuit voltage (VOC) = 0.65 V and a fill factor (FF) = 0.53, resulting in an overall power conversion efficiency (PCE) = 6.4%. While the DSC using as deposited CZTS film as a CE showed the PCE = 3.7% with JSC = 13.38 mA cm(-2), VOC = 0.57 V and FF = 0.48. Thus, the spray deposited CZTS films can play an important role as a CE in the large area DSC fabrication.The work presented in this paper was done under the Department of Science and Technology (DST)–Research Council UK (RCUK) project “Advancing the efficiency and production potential of excitonic solar cells”. Sanjay Kumar Swami acknowledges Ministry of National Renewable Energy (MNRE), New Delhi, India for providing the financial assistantship. Mr. Firoz Alam is also thanks for helping in initial impedance measurements