Electrodeposition of copper on copper single crystal (100) face in presence of chloride ions

Observations of copper electrodeposits on to the (100) plane of copper was made from highly purified solutions of copper sulphate containing known concentration of hydrochloric acid from 10−10 to 10−1 m/L. In pure solutions at current densities of 5 and 10 mA/cm.2 layers and pyramids were noticed. In the presence of hydrochloric acid of concentration 10−9 to 10−5 m/L there is a gradual decrease of distance between successive steps. At 10−4 m/L of HCl there was the breaking of layers giving rise to ridge type of growth. With the increase of concentration to 3·5×10−3 m/L pyramids appear again. On increasing the concentration of HCl to 10−2 m/L there was the formation of triangular pyramids of cuprous chloride and on still increasing the concentration, polycrystalline type of deposit was noticed. The transition from layer to ridge, ridge to pyramids and to polycrystalline deposit occurs at all c.d. studied but the critical concentration of HCl needed for the transition depends upon the current density. Communicated by Prof. M. Santappa,f.a.sc

Growth of Cu2Cl2 and Cu2Br2 on single crystal faces and polycrystalline copper during dissolution in CuSO4 + H2SO4

Cu2Cl2 and Cu2Br2 precipitate and crystallise in the form of triangular pyramids and dendrites when Cu is immersed in aerated, acid CuSO4 solution containing HC1 or HBr. The critical concentration of HC1 or HBr for this precipitation depends on the surface of the copper: Poly-crystalline < (110) < (100) < (111). In the deaerated solution there is no precipitation of Cu2Cl or Cu2Br2 even at a high concentration of HC1 or HBr when only preferential etching occurs

Performance Analysis of Reactive Routing Protocols AODV, DYMO, DSR, LAR in MANETs

MANETs are one the cutting-edgeevolving wireless technologies. The routing in mobile ad hoc networksplays a vital role and has been researchedwide-range in last decade. The routing protocols are classified as proactive,reactive and hybrid. Reactive routing protocols are considered for its advantages compared to others. In this paper, reactive routing protocols, Ad Hoc On-demand Distance Vector (AODV), Dynamic MANET On-demand (DYMO) protocol, Dynamic Source Routing protocol (DSR), Location Aided Routing protocol have been selected to analyze the performance and compare the routing protocols by varying Network size and Mobility speed to various levels. The performance metrics analyzed were Average Throughput, Average End-to-End Delay, Average Jitter, Energy Consumed in Transmit Mode, Energy Consumed in Receive Mode. The simulations were carried on Exata 5.4 simulator. The analysis of the routing protocols for the configuration setting is presented at the conclusion

Seat of the Joshi Effect in A.C. Silent Discharges

Some experiments on the positive and negative Joshi effects in 'sleeve' discharge tubes containing iodine vapour and hydrogen gas have been performed to Study the effect of illuminating the different parts of each discharge tube successively by a narrow beam of strong light. The results of these experiments are given in the piper with an account of the experimental arrangements. The results have shown that the Joshi effect (positive and negative) is associated predominantly with the regions of the electrodes. The role of the discharge column of the lube in the production of the Joshi effect, if any, is, however, regarded as uncertain. The effect of stray light affecting the electrodes after being scattered from the illuminated part of the discharge tube is considered in discussing the experimental results of Agashe

Study of Unsteady State Thermal Characteristics of Homogeneous and Composite Walls of Building and Insulating Materials for Passive Cooling

Passive cooling is one of the methods to keep the building cool and to reduce the load on air conditioner. Passive cooling demands the study of the thermal characteristics like admittance, transmittance, decrement factor, time lag, surface factor and surface factor time lags. These characteristics were determined for both homogeneous and composite walls. The buildings are built with composite wall. This demands the study of thermal characteristics of composite wall. In this study, five building materials like Laterite stone, Burnt brick, Mud brick, Reinforced brick and Fly ash bricks were selected as homogeneous building materials. Five local Insulating materials such as Saw dust, Rice husk, Coir board, Jute felt and Jute fiber were selected to form the composite wall along with building materials. The composite walls were framed using the combination of building materials and insulation materials. Total hundred combinations of composite walls, without insulation (Configuration-A) and with insulation material located at inner side (Configuration-D), insulation material at mid plane (Configuration-C) and insulation material at outer side (Configuration-B) of the composite wall were studied. To study the thermal characteristics of such configurations of composite wall, one dimensional heat flow diffusion equation was solved using matrix algebra under periodic boundary conditions. The penetration length of thermal waves, the phase velocity of the heat wave in the wall and optimum fabric thickness of the selected building and insulating materials were calculated. From this study it is found that the decrement factors of the fly ash brick (0.401) and jute felt (0.4) are the least and the time lags of the fly ash bricks (8.15h) and jute felt (8.75h) are the highest among all the studied homogeneous building and insulating materials. Hence these two homogeneous materials are more effective building and insulating materials at suppressing temperature swings. It is summarized that insulation located at the inner surface (Configuration D) of the composite wall gives the lower time lags and higher decrement factors. This is the worst condition of insulating the wall among all the studied configurations. It is also concluded that fly ash brick composite walls with jute felt insulation located at the mid plane of the wall give greater time lags (11.17 h) and reinforced brick composite walls with rice husk insulation located at the inner side of the wall give lower time lag values (7.37h). It was also observed that fly ash brick composite walls with coir board insulation located at the outer side of the wall give the lowest value of decrement factor (0.17) and reinforced brick composite walls with jute fiber insulation located at the inner side of the wall give higher decrement factors (0.37). Fly ash brick composite walls with jute felt insulation located at the mid center plane of the wall are the most recommended composite walls among all the studied composite walls. Henceforth this composite wall is recommended for passive cooling

ANFIS Based Temporally Ordered Routing Algorithm to Enhance the Performance in Mobile Ad-hoc Networks

A Mobile Ad hoc network (MANET) consists of mobile nodes, a router with multiple hosts and wireless communication devices. Mobile Adhoc Networks can operate without any fixed infrastructure and can survive rapid changes in the network topology. Link failure and route failure takes place. Provisioning of QoS is a problem in MANETs. TORA is the only protocol which supports either Proactive or Reactive modes in routing. In this paper, we incorporated the ANFIS to the existing TORA to enhance the performance. Evaluating the performance of ANFIS-TORA is the simulation by using OPNET MODELLER. Evaluating the relative performance with respect to performance metrics are Throughput, End-to-End delay, and Network Load. We generate various simulation scenarios with varying network size such as small, medium and large. In this paper, ANFIS based TORA for MANETs are considered and their performance was analyzed for different network size. From the simulation results, we conclude that ANFIS based TORA outperforms for small medium and large network. Throughput was increased by 48.27% in small network, 61.29% in medium network and 8.29% in the large network in Reactive mode. In Proactive, the throughput is increased by 103.46% in small network, 4.58% in medium network and 5.05% in large network

Performance Comparison of Geographic LAR1 with On-demand AODV and DSR Routing Protocols for MANETs

MANET is a self organizing, infrastructure-less network, that consist number of low power mobile nodes connected by wireless radio frequency signals. These nodes in this dynamic environment move freely in any direction, which leads to change in network topology. It is very difficult to recharge or replace the battery of the nodes. To maximize the battery life and lifetime of the network, the nodes are required to be energy conserved. The mobile node energy can be affected by the performance of the routing protocol. We have considered three routing protocols, one is location based protocol - LAR1 and the other two are non location based protocols - AODV and DSR. The energy performance metrics, routing power and residual energy in all the three modes –transmitting, receiving and idle mode are evaluated using these routing protocols in Mobile Ad-hoc Networks and also other performance metrics in application layer are evaluated, which are throughput, end-to-end delay and average jitter. The simulation is carried out by using EXata -5.4

Performance Analysis of Cognitive Radio Networks (IEEE 802.22) for Various Network Traffics

In nowadays the number of wireless users and applications increases, it has become more and more difficult for the proper spectrum utilization by allocate frequencies. However measurements have shown that there is no spectrum scarcity; rather, there is inefficient utilization only. Cognitive Radio (CR) to facilitate efficient utilization of the radio spectrum in a fair-minded way and to provide highly reliable communication for all users of the networks. In this paper, a simulation framework based on NetSim simulator is proposed. This framework can be used to investigate and evaluate the impact of lower layers, i.e., data link layer and physical layer. Due to the importance of packet drop probability, delay and throughput as QoS requirements in real-time reliable applications, these metrics are evaluated over Cognitive Radio Networks (CRNs) through NetSim simulator. Our simulations demonstrate that the design of new networks over CRNs should be considered based on CR-related parameters such as activity model of Primary Users(PU), Secondary Users(SU),sensing time ,spectral efficiency, throughput, delay and Interference. An Analysis of the result shows that, the CBR traffic is the best in terms of throughput and spectral efficiency when the different conditions of PUs and SUs