Growth,mortality and stock status of mullets (Mugilidae) in Chilika Lake,India

The growth, mortality and stock status of grey mullets Chelon parsia (Ham. 1822), Chelon planiceps (Val. 1836) and Mugil cephalus (Linn. 1758) were investigated during December 2010 to November 2011 from Chilika Lake, Asia, largest brackish water lake. The length‐based analysis, using length frequency data collected from fish landing centres, formed the basic study methodology. Growth function and population parameters were studied using FAO ‐ICLARM Stock Assessment Tools‐II (FiSAT ‐II ). The von Bertalanffy growth function (VBGF ) was established as L _t  = 321 mm*(1 ? exp (‐0.98 year^?1 × (t + 0.085 year)) for C. parsia , L _t  = 315 mm × (1 ? exp (?0.80 year^?1 × (t  + 0.105 year)) for C. planiceps and L _t  = 700 mm*(1 ? exp (?0.70 year^?1*(t  + 0.097 year)) for M. cephalus . Lower K and higher L _∞ values for M. cephalus indicated slow growth and high longevity of the species, compared to other grey mullets. Length–weight relationships were derived, indicating isometric growth for grey mullets. Recruitment of mullets was observed throughout the year, with a peak during April–July. About 50% of the mullets were caught by fishing gear before reaching their first year of age. The level of exploitation (E  ≥ 0.60) was more than the optimum level (E  = 0.4 for pelagic stock), indicating overexploitation of grey mullets in Chilika Lake. Moreover, the average annual yields of three mullets were observed to be higher than the estimated maximum sustainable yields (MSY ), also indicating overharvesting of mullets. Thus, the mullets could be considered one of the highly overexploited resources in Chilika Lake. The findings of this study will facilitate the development of appropriate management strategies for the mullet fishery in Chilika Lake.     

Molecular Dynamics Simulation of Diffusion of Fe in HCP Ti Lattice

Diffusion of a single Fe atom in a defect free hcp Ti lattice was studied using molecular dynamics (MD) simulation. Modified Embedded Atom Method potentials derived by Sa et al. (Scripta Mater 59:595, 2008) were used for carrying out the MD simulations. These potentials were verified by estimating the physical properties of the Fe–Ti system such as cohesive energy, bulk modulus and the shear constants. Fe atom trajectory in Ti lattice was traced in the temperature range of 500–900 °C. Diffusivity of Fe (\( D_{Fe} \)) atom in Ti lattice was obtained from the estimation of mean square displacement for total time of simulation at each temperature. \( D_{Fe} \) at 900 °C was obtained as 7.784?×?10^?15 m²/s. From the Arrhenius analysis of \( \ln D_{Fe} \) versus temperature, the activation energy required for the diffusion of Fe atom in hcp Ti lattice was obtained as 117 kJ/mol.     

Reduction of emissions in a biodiesel‐fueled compression ignition engine using exhaust gas recirculation and selective catalytic reduction techniques

This paper analyzes the emissions of a single‐cylinder diesel engine fueled with biodiesel, using selective catalytic reduction (SCR) and exhaust gas recirculation (EGR) techniques. The aim of this paper is to compare both EGR and SCR techniques, which were studied under different brake powers. Grape seed biodiesel was used as a test fuel. Experiments were performed by both techniques at different loads and rates to find out the performance change in the engine and the change in the emission rates using both the techniques. Then the observations from both the techniques were compared, concluding that both the techniques show a sufficient reduction in NOx. Using the abovementioned techniques, a reduction in hydrocarbon (HC), carbon monoxide (CO), carbon dioxide (CO₂), nitrogen oxides (NOx), and smoke was observed. The EGR technique is more suitable for low‐load engine vehicles, as it affects the efficiency of the engine with an increase in the fuel consumption, whereas the SCR technique is suitable for high‐load engines, which do not affect the efficiency of the engine with a decrease in the fuel consumption.     

Optical protein modulation via quantum dot coupling and use of a hybrid sensor protein

Harnessing the energy transfer interactions between the optical protein bacteriorhodopsin (bR) and CdSe/ZnS quantum dots (QDs) could provide a novel bio-nano electronics substrate with a variety of applications. In the present study, a polydimethyldiallyammonium chloride based I-SAM technique has been utilized to produce bilayers, trilayers and multilayers of alternating monolayers of bR, PDAC and QD's on a conductive ITO substrate. The construction of multilayer systems was directly monitored by measuring the unique A570 nm absorbance of bR, as well as QD fluorescence emission. Both of these parameters displayed a linear relationship to the number of monolayers present on the ITO substrate. The photovoltaic response of bilayers of bR/PDAC was observed over a range of 3 to 12 bilayers and the ability to efficiently create an electrically active multilayered substrate composed of bR and QDs has been demonstrated for the first time. Evaluation of QD fluorescence emission in the multilayer system strongly suggests that FRET coupling is occurring and, since the I-SAM technique provide a means to control the bR/QD separation distance on the nanometer scale, this technique may prove highly valuable for optimizing the distance dependent energy transfer effects for maximum sensitivity to target molecule binding by a biosensor. Finally, preliminary studies on the production of a sensor protein/bR hybrid gene construct are presented. It is proposed that the energy associated with target molecule binding to a hybrid sensor protein would provide a means to directly modulate the electrical output from a sensor protein/bR biosensor platform.     

Transesterification,emission, and performance analysis of coconut oil biodiesel- alumina nanoparticles mixture in diesel engine

ABSTRACT

In order to improve its transesterification process, performance and emission parameters, nanoparticles are mixed to neat biodiesel. This work aims to investigate the cause of alumina nanoparticles on transesterification, emission and performance of coconut biodiesel. Two fuel samples are prepared by transesterification process with and without adding alumina nanoparticles. Experimental results revealed that the nitrogen oxide emission and smoke emission are reduced by 6% and 8% for coconut biodiesel by transesterification with adding alumina nanoparticles (CBD100A) when compared to coconut biodiesel by transesterification without alumina nanoparticles (CBD100). In addition, the introduction of alumina nanoparticles in coconut biodiesel during transesterification reduces the unburned hydrocarbon, carbon monoxide emissions considerably. Experimental results show that the CBD100A reduces fuel consumption which increases brake thermal efficiency.     

Origin of problems encountered in rice bran oil processing

Rice bran oil, not being a seed‐derived oil, has a composition qualitatively different from common vegetable oils and the conventional vegetable oil processing technologies are not adaptable without incurring huge losses. The oil's unusual high content of waxes, free fatty acids, unsaponifiable constituents, phospholipids, glycolipids and its dark color, all cause difficulties in the refining process. An attempt was made in this investigation to look into factors that are responsible for such difficulties and to develop suitable methodologies for physical refining of rice bran oil. Special attention was given to dewaxing, degumming and deacidification steps. The high content of glycolipids (∼6%) present in the oil was found to be a central problem and their removal appeared crucial for successful processing of the oil. We have also isolated and identified, for the first time, phosphorus‐containing glycolipids that are unique to this oil. These compounds prevent a successful degumming of the oil and their high surface activity leads to unusually high refining losses during alkali refining. A number of simple processes has been evolved, including 1) a simultaneous dewaxing and degumming process, 2) an unusual enzymatic process to degum the oil, 3) processes for the removal of the glycolipids including the phosphoglycolipids and 4) a process for the isolation of the glycolipids which may have potential applications in the food, cosmetic and pharmaceutical industries. The processing protocol suggested here becomes the first and only one to produce an oil with less than 5 ppm of phosphorus from crude rice bran oil, rendering it thus suitable for physical refining. We believe that the present results are very significant and should contribute to a better utilization of this valuable oil.     

Modification in the Microstructure of Mod. 9Cr-1Mo Ferritic Martensitic Steel Exposed to Sodium

Mod. 9Cr-1Mo is used as the structural material in the steam generator circuit of liquid metal-cooled fast breeder reactors. Microstructural modifications on the surface of this steel are investigated after exposing to flowing sodium at a temperature of 798 K (525 °C) for 16000 hours. Sodium exposure results in the carburization of the ferritic steel up to a depth of ~218 µm from the surface. Electron microprobe analysis revealed the existence of two separate zones with appreciable difference in microchemistry within the carburized layer. Differences in the type, morphology, volume fraction, and microchemistry of the carbides present in the two zones are investigated using analytical transmission electron microscopy. Formation of separate zones within the carburized layer is understood as a combined effect of leaching, diffusion of the alloying elements, and thermal aging. Chromium concentration on the surface in the α-phase suggested possible degradation in the corrosion resistance of the steel. Further, concentration-dependent diffusivities for carbon are determined in the base material and carburized zones using Hall’s and den Broeder’s methods, respectively. These are given as inputs for simulating the concentration profiles for carbon using numerical computation technique based on finite difference method. Predicted thickness of the carburized zone agrees reasonably well with that of experiment.     

Transport protocols for data center networks: a survey of issues,solutions and challenges

In recent years, data centers play an important role in academia and industry for supporting various services and applications. Compared with other IP networks, data center networks have some special features such as many-to-one communication pattern with high bandwidth, low latency, auto-scaling, shallow buffered switches and multi-rooted tree topology. Owing to these special features of data center networks, traditional TCP suffers from severe performance degradation. For improving the performance of TCP in data center networks, various solutions have been proposed in recent years. This article presents a comprehensive survey of existing transport layer solutions proposed for mitigating the problems of TCP in data center networks. The objective of this article is threefold: to discuss about the issues of TCP in data center networks; to introduce various transport layer solutions and finally to compare and discuss the challenges of existing solutions proposed for improving the performance of TCP in data center networks.