Prediction of pressure drop during forced convection boiling of mixture of refrigerants 13 and 12

Pressure drop measurements during forced convection boiling of pure R-12 and mixture of R-13 and R-12 have been done inside horizontal tubes. The frictional component of the pressure drop has been found to be a function of mixture composition. The authors have successfully developed a correlation on the basis of C-S method, which has been found to give better agreement than an earlier reported method based on M-N correlation.     

Adriamycin depresses in vivo and in vitro phosphatidylethanolamine N-methylation in rat heart sarcolemma

Adriamycin, an effective anticancer chemotherapeutic agent, causes an insidious and delayed cardiotoxicity. Different subcellular abnormalities including calcium transport changes in the sarcolemma (SL) as well as downregulation of the adrenergic system have been shown to be associated with the development of this cardiomyopathy. Since both of these activities are influenced by phospholipid methylation, effects of adriamycin on the three catalytic sites of SL phosphatidylethanolamine N-methyltransferase were examined. Rats were administered with a cumulative dose of adriamycin (15 mg/kg) over 2 weeks and examined after 3 weeks. Vehicle injected animals served as controls. Dyspnea, high mortality rate, ascites and decrease in aortic and left ventricular systolic pressure, as well as increase in left ventricular end diastolic pressure were seen in the adriamycin group. Myocardial cell damage typical of adriamycin cardiomyopathy, i.e. sarcotubular swelling, vacuolization and myofibrillar drop-out, was also apparent. Total methyl group incorporation into SL phosphatidylethanolamine using radiolabeled S-adenosyl-L-methionine as the donor was significantly depressed in the 3 week group at catalytic sites II and III. Decreased production of methylated intermediates, phosphatidyl-N-monomethylethanolamine and phosphatidyl-N,N-dimethylethanolamine as well as phosphatidylcholine (PC) was seen. Depression of phosphatidylethanolamine N-methylation was also noticed when SL, isolated from untreated hearts, was exposed in vitro to different concentrations (10, 100 and 1000 microM) of adriamycin. Inhibition of phosphatidylethanolamine N-methylation appears to be mediated by adriamycin-induced increase in the oxidative stress and may contribute in the pathogenesis of subcellular changes associated with this cardiomyopathy.     

Heat transfer correlations for the forced convection boiling of R12-R13 mixturesCorrélations du transfert de chaleur pour l'ébullition en convection forcée de mélanges de R 12 et R 13

Correlations for predicting the local heat transfer coefficient during forced convection boiling of mixed refrigerants have been developed for four compositions of binary mixtures of R13 and R12. Of the several correlations examined with nearly equal promise, the Lavin-Young type has been found the best. Generalized correlations have also been developed for all mixture compositions. Effect of concentration factor, CF, has resulted in marginal improvement of the correlations. Liquid and vapour phase Prandtl numbers have also been found to affect the generalized correlations for predicting the local heat transfer coefficient.     

Moralism: mobility prediction with link stability based multicast routing protocol in MANETs

In recent research, link stability is getting tremendous attention in mobile adhoc networks (MANETs), because of several impediments that occur in a reliable and robust network. Link stability metric is used to improve network performance in terms of end-to-end delay, data success delivery ratio (DSDR) and available route time (ART). Energy consumption, bandwidth and communication delay of major concern in ad hoc networks. A high mobility of MANET nodes reduces the reliability of network communication. In a dynamic networks, high mobility of the nodes makes it very difficult to predict the dynamic routing topology and hence cause route/link failures. Multicast in MANETs is an emerging trend that effectively improves the performance while lowering the energy consumption and bandwidth usage. Multicast routing protocol transmits a packet to multicast a group at a given time instant to achieve a better utilization of resources. In this paper, node mobility is considered to map better their movement in the network. So, the links with long active duration time can be identified as a stable link for route construction. Variation in signal strength is used to identify whether the direction of the node is towards or away from estimating node. We consider signal strength as QoS metric to calculate link stability for route construction. Efforts are made to identify the link with highly probable longer lifetime as the best suitable link between two consecutive nodes. We predict the movement time of nodes that define the route path to the node destination. Exata/cyber simulator is used for network simulation. The simulation results of the proposed routing protocol are compared with on-demand multicast routing protocol and E-ODMRP, which works on minimum hop count path. Analysis of our simulation results has shown improvement of various routing performance metrics such as DSDR, ART, routing overhead and packet drop ratio.     

Development of hydrokinetic energy technology: A review

The drastic change in climatic conditions has led to shift towards the review of sustainable strategies in the renewable energy sector. Hydrokinetic technology has various benefits over the conventional methods, which can be helpful in achieving the desired sustainable development. In the present study, an outline for the conversion of hydrokinetic energy along with its challenges has been discussed. The study comprises of three steps involving collection of properties required for site characterization followed by selection of the suitable hydrokinetic device as per the site characteristics and the determination of impact on the flow condition due to device installation. The characteristics of the site govern the selection of the device, its mooring arrangements, and augmentation. The arrangement of devices as a single unit or in an array will have an impact on the flow conditions. The altered flow condition will in turn affect and change the characteristics of the site. This three‐step process is interlinked and will have a cumulative impact on the environment. The influence of environmental impact and cost of energy, which are the two major factors for the success of this technology, are also discussed. Further, various challenges faced by hydrokinetic technology in its development are explored. It is concluded that only the optimization of a hydrokinetic device for its efficiency improvement will not be fruitful until its impact on flow condition is considered for optimization.     

Evaluation of different rodenticidal baits against rodent population in cucumber (Cucumis sativus) crop fields

The baits used consisted of 2% zinc phosphide and 0.005% bromadiolone. The baitings were carried out at the flowering stage of cucumber crop. Double baiting treatments comprising zinc phosphide and bromadiolone in different combinations resulted in better reduction of rodent population and crop damage. Deployment of different rodenticidal treatments saved yield loss from 7.00 to 11.82q/ha. Thus, accomplishing cost benefit ratio of 1:88 to 1:107. Bromadiolone followed by bromadiolone, the most profitable combination is suggested for control of rodent population in cucumber crop fields.     

Covariance of narrow-band noise in multiple beams of a phased-array system

Covariance of narrow-band noise among two simultaneous beams, looking toward different directions with identical power patterns, for a phased array system is formally analyzed. It is shown that the noise correlation coefficient as a function of the angle of separation between two beams is the same as the normalized beam power pattern. This result is independent of the way the beams are formed, in particular these conclusions for both the total power beam systems and the correlator beam systems are examined in detail.     

Performance prediction of solar air heater having roughened duct provided with transverse and inclined ribs as artificial roughness

An experimental study has been carried out to investigate the effective efficiency of a solar air heater duct provided with transverse and inclined ribs as artificial roughness elements on the absorber plate. The range of parameters considered for the present investigation; Reynolds number (Re) 2000–14,000, relative roughness pitch (p/e) 3–8 and a fixed value of relative roughness height (e/D) of 0.030. The effective efficiency has been computed based on the experimentally determined values for the range of parameters considered. Further an attempt has also been made to optimize the thermal efficiency for the same system under similar conditions by Taguchi method.     

Multidestination message passing in wormhole k-ary n-cube networkswith base routing conformed paths

This paper proposes multidestination message passing on wormhole k-ary n-cube networks using a new base-routing-conformed-path (BRCP) model. This model allows both unicast (single-destination) and multidestination messages to co-exist in a given network without leading to deadlock. The model is illustrated with several common routing schemes (deterministic, as well as adaptive), and the associated deadlock-freedom properties are analyzed. Using this model, a set of new algorithms for popular collective communication operations, broadcast and multicast, are proposed and evaluated. It is shown that the proposed algorithms can considerably reduce the latency of these operations compared to the Umesh (unicast-based multicast) and the Hamiltonian path-based schemes. A very interesting result that is presented shows that a multicast can be implemented with reduced or near-constant latency as the number of processors participating in the multicast increases beyond a certain number. It is also shown that the BRCP model can take advantage of adaptivity in routing schemes to further reduce the latency of these operations. The multidestination mechanism and the BRCP model establish a new foundation to provide fast and scalable collective communication support on wormhole-routed systems