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61.
ABSTRACT This article reports a study on heat transfer and flow characteristics of nano fluid consisting of water and ethylene glycol as base fluid with different concentrations of SiO2as nanoparticles (0.1% and 0.15%) are flowing in a shell and tube exchanger. The SiO2 nanoparticles of about 15 nm diameter are used in this study. The results showed that the heat transfer coefficient of nano fluid was slightly higher than that of the base fluid at the same inlet temperature and at the same mass flow rate. It was observed that heat transfer coefficient of nano fluid was increased with an increased mass flow rate. Heat transfer coefficient was noticed to increase with the increase of the volumetric concentration of the SiO2. But increasing the volume concentration caused the increase in the viscosity of the nano fluid resulted in an increase in friction factor. 相似文献
62.
The uniform flow distribution in the upstream side of open channel flow passages is to be ensured at different flow rates. This finds critical importance in many industrial applications including chemical plants and nuclear reactors. This paper describes the method for achieving the uniform flow pattern in open channel flow passages with the aid of stream equaliser plates of different lengths and porosities. 相似文献
63.
Baskar Senthilkumar Chinnasamy Murugesan Lalit Sharma Shubham Lochab Prabeer Barpanda 《Small Methods》2019,3(4)
“Building better batteries” remains an ongoing process to cater diverse energy demands starting from small‐scale consumer electronics to large‐scale automobiles and grid storage. While Li‐ion batteries have carried this burden over the last three decades, the ever‐growing and highly diverse applications (based on size, energy‐density, and stationary vs mobile usages) have led to an era of “beyond lithium‐ion batteries.” In this postlithium‐battery era, sodium‐ion batteries (NIBs) have emerged as a pragmatic option particularly for large‐scale applications. They attract attention due to the abundance and uniform geographic distribution of sodium‐based minerals, materials/process economy, and well‐known (de)intercalation mechanisms, in particular for stationary applications independent of size/weight restriction. Parallel to the Li‐ion batteries, the cathode (positive electrode) plays a key role in overall performance, leading to the exploration of various layered and 3D framework insertion materials. While layered oxides deliver high capacity, polyanionic hosts offer structural stability, operational safety, and tunable redox potentials. It can be further exploited in “mixed polyanion” cathode materials combining more than one kind of polyanion units. This article focuses on mixed polyanionic cathode materials for NIBs. It renders a sneak‐peek on suites of mixed polyanionic insertion materials discussing their structure, overall electrochemical performance, and future perspectives. 相似文献
64.
65.
S. Saranya S. T. Senthilkumar K. Vijaya Sankar R. Kalai Selvan 《Journal of Electroceramics》2012,28(4):220-225
The MnWO4 nanorods were successfully synthesized by surfactant assisted ultrasonics method and characterized its structural (XRD), morphological (SEM) electrical (solid state impedance) and electrochemical (CV) properties. The X-ray diffraction patterns inferred the formation of highly crystalline monoclinic structure of MnWO4. The formation of nanorods with the aspect ratios of 30–40?nm were reveals from SEM image. The maximum d.c. electrical conductivity was found to be 4.40?×?10?5?S/cm at 570°C for MnWO4 nanorods prepared by surfactant assisted ultrasonic method. The quasi-rectangular behavior of cyclic voltammogram inferred the supercapacitive behavior of the prepared MnWO4 nanorods. 相似文献
66.
In the present study, the effect of various levels of bulk and free water content and its distribution on the colour of cotton fabrics dyed with direct dyes and their combinations were analysed. Twill and plain structures with two different parameters of fabric construction were chosen. The dyed samples were adjusted to different levels of wet pick‐up, with water ranging from 50% to 125% on the bone dry weight of the fabric (odwf) to achieve various levels of bulk water content. Further, the residual moisture content of the samples was adjusted to 40–10% odwf by means of hot air drying at different temperatures to obtain different levels of free water content and its distribution. For the assessment of colour and its comparison, the parameters ΣK/S and values were used. In order to bring out the true effect of moisture distribution and fabric structure, normalisation of dye uptake in the fabric based on weight and area were considered, respectively. The plain structures show a higher increase in colour than the twill structures when the bulk water content increases. At the same time, the fabric structures do not play a significant role, with increase in colour attributable to change in drying temperature. The findings reveal that the bulk water content, drying temperature and fabric geometry affects the colour of the fabric significantly. 相似文献
67.
This research involves the optimization of different variables of the operating conditions to prepare activated carbon from pomegranate peels (Punica granatum peel). For this purpose, a statistical method called Response Surface Methodology (RSM) has been adopted to economize the number of experiments and their meaningful interpretation. Activated carbon was produced by chemical activation (H3PO4). RSM was used to evaluate the variables considered in the preparation of activated carbon such as impregnation ratio (2–4?g H3PO4/g pomegranate peel), temperature (400–600°C), and activation time (30–90?min), experimented using a three-variable Box–Behnken Design (BBD) based on a quadratic model and an RSM tool provided by Design Expert 8.0.4 (STAT-EASE Inc., Minneapolis, USA). The responses analyzed for optimization were the methylene blue number and the iodine number. The factors that are significant influencing the activated carbon preparation have been identified by an analysis of variance (ANOVA). The optimum conditions established were impregnation ratio of 2.78, activation temperature of 575°C, and activation time of 73?min. 相似文献
68.
Spillway weirs are the system for regulating the flow in open channel flow passages. Weirs are commonly used to alter the flow of rivers to prevent floods, measure discharge and also in nuclear reactors for uniform cooling purposes. This paper describes the hydraulic experiments conducted for finding the air entrainment on water under laminar flow conditions in open channel flow passage with various profiles of spillway at flow rates in the range of 100–650?lpm. The concept of the spillway system allows stabilisation of the free level of water and avoids variation in the free level of water along the flow passage as a function of flow rate. The main problem in the spillway is the profiling of weir crest. The criteria that need to be satisfied are: (i) there should be no flow separation from the crest and (ii) there should be a uniform circumferential flow to avoid flow asymmetry in the passage. Separation of flow leads to large impact velocity of the falling water, which would lead to large-scale entrainment of air. When flow adheres to the weir crest and upstream, the impact velocity of water with the free surface would be less and hence entrainment would also be less. 相似文献
69.
The utilization of plastics has increased in packing sectors consistently, which lead indirectly to increased volumes of plastic wastes posing an environmental threat. Several utilization and recycling techniques of waste plastics are being practiced commercially around the world. In this article, recent conversion techniques of fuel oil from waste plastics and its utilization on a compression‐ignition engine are discussed. Recent statistics says most of the plastic wastes are generated from packing industries that contains polyethylene, polypropylene. In this connection, conversion techniques of polyethylene and polypropylene practiced frequently by researchers include catalytic processing, thermal degradation, and co‐processing. The effect of various parameters like catalysts, reaction temperature, and reaction time of the aforementioned conversion techniques are discussed in this review. Also, few research works about the utilization of waste plastic oil with a compression‐ignition engine along with engine performance and emissions in various blends of diesel with plastic oil are highlighted here. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
70.
The influence of vortex spinning parameters on the hairiness properties of polyester/cotton vortex yarn has been studied. Polyester/cotton yarn of 50:50 blend ratio has been produced in two different counts (Ne 20s and Ne 40s) each with four different spinning parameters (delivery speed, spindle size, feed ratio and nozzle pressure). Experiments are designed with the aid of response surface method. Accordingly, different samples are produced with three levels of each parameter. The hairiness index H and zweigle hairiness have been evaluated from the samples produced with these combinations. It is found that the hairiness index H of both coarser and medium count vortex yarns are influenced by all the spinning parameters considered for this study. Also, zweigle S3 values of both coarser and medium count vortex yarns are influenced by all the four parameters. The interactions of some of the spinning parameters have significant influence on the hairiness index, H of both coarser and medium count vortex yarn. Also, few of the interactions have significant influence on zweigle S3 values of both coarser and medium count vortex yarns. 相似文献