Implications of particle size to transient stage of deep bed filtration

This study was aimed at investigating the effect of particle size, mostly in the submicron range, on break-through stage of filtration. Latex beads, with diameters ranging from 0.46- to 2.967-μm were filtered through filter grains of diameters 0.1-, 0.175- and 0.45-mm. Experimental conditions were chosen so as to obtain breakthrough curves. The experimental results showed that the initial efficiency follows the pattern reported by previous experimental and theoretical studies, i.e., lower efficiency for 0.825-μm particles which fall in the range of critical size. However, the particle removal during the transient stage increased with an increase in particle size for the range of sizes studied. This pattern is qualitatively confirmed by the theoretical predictions of Vigneswaran and Chang (1986) model. This study also provides experimental verification of the effect of the ratio of particle size and grain size at different stages of filtration.     

Inequalities and externalities of power sector: A case of Broadlands hydropower project in Sri Lanka

The objective of the paper is to estimate environmental externalities related to a run of river project in Sri Lanka and to investigate inequity in distribution of impacts among different social groups. Diversion of the river resulted in loss of water sports (for high-income groups both local and remote), loss of historical monuments (for remote high-income groups) and recreation losses (for local poor). Removal of forest cover leads to loss of non-timber products (for local poor) and carbon storage (for remote high- and low-income groups). Loss of home garden productivity was borne by local poor groups. Benefit of the project, generation of 145 GWh annually, was a gain for the grid connected groups. The impacts were valued using various valuation methods. The base case of the cost benefit analysis resulted in NPV of US$ 11,335,730. When distributional weights are applied for different income groups, both the sign and magnitude of net benefits change. In order to be viable, the project needs diversion of at least 9% of generated electricity to the poorest households in the country. Implications for energy policy towards reducing externality and inequality impacts are also discussed.     

Adjusting the TCP Sending Rate and Retransmissions after Retransmission Timeouts Based on One-Way Queuing Delay in Wireless Mesh Network

Wireless Mesh Network (WMN) is regarded as a viable solution to provide broadband Internet access flexibly and cost efficiently. Improving the performance of Transmission Control Protocol (TCP) in WMNs is an active research area in the networking community. The existing solutions proposed for improving the TCP performance has concentrated on differentiating the DATA packet drops in the forward direction induced by both network congestion as well as transmission errors. However, the recent studies show that in WMNs packet drops occur not only in the forward direction but also in the reverse direction particularly due to hidden terminal, hidden capture terminal, link asymmetry etc. The loss of ACK packets in the reverse direction cause frequent retransmission timeouts subject to needless retransmissions and unnecessary slowing down the growth of congestion window, which causes the performance degradation of TCP. In this paper, we introduce a sender side TCP algorithm, called detection of packet loss (DPL), which is capable to distinguish the type of packet drops either DATA or ACKs caused by transmission errors as well as network congestion based on one-way queuing delay and react accordingly. To justify our contributions, we implement DPL in Qualnet simulator and compare its performance against existing TCP solutions via extensive simulations. Our simulation results show that the proposed algorithm can accurately distinguish the type of packet drops whether it is a DATA or ACK caused by transmission error or congestion and can significantly improve the performance under a wide range of scenarios in WMNs.     

Metastable Phase Transformation in Ti-5Ta-2Nb Alloy and 304L Austenitic Stainless Steel under Explosive Cladding Conditions

Ti-5Ta-2Nb alloy was clad on 304L austenitic stainless steel (SS) using the explosive cladding process. Both Ti-5Ta-2Nb and 304L austenitic steel were severely deformed due to high pressure (in the gigapascal range) and strain rate (10⁵/s), which are characteristics of explosive loading conditions. Consequent changes produced in the microstructure and crystal structure of both the alloys are studied using electron microscopy techniques. The microstructure of both Ti-Ta-Nb alloy and 304L steel showed evidence for the passage of the shock waves in the form of a high number density of lattice defects such as dislocations and deformation twins. In addition, both the alloys showed signatures of phase transformation under nonequilibrium conditions resulting in metastable transformation products. 304L SS showed martensitic transformation to both ????(bcc) and ??(hcp) phases. Microscopic shear bands, shear band intersections, and twin boundaries were identified as nucleation sites for the formation of strain-induced phases. Ti-Ta-Nb alloy underwent metastable phase transformation to an fcc phase, which could be associated with regions having a specific morphology.     

Detailed analysis on emission and performance characteristics of neat biofuel-fuelled diesel engine

ABSTRACT

There is an entanglement over the rapid exhaust of fossil fuel and soreness of environmental changes. Biofuels are acting as an alternative resource for petroleum products and also salve of emissions control and engine performance improvement. Scholars have seen the supreme use of bio-fuel apparent, as it will influence greenhouse effect. Investigation results show the diminished heating value in congruence with conventional pabulum, so it had depleted more in brake mean effective-fuel power ratio and proliferated NO_x compared with diesel fuel. The article mainly focuses on the selection – process of biofuel and analysis of performance (BSFC, EGT and brake thermal efficiency), emissions (CO, NO_x, CO₂, PM and HC) and combustion (NHR and CP) of the engine are exclusively discussed and summarised. Finally, stability, opportunity, and restraint of a selection of alternative fuel and investigation and study on the engine were asserted to guide further future exploration and evolution in that domain.     

Targeted Delivery of siRNA‐Generating DNA Nanocassettes Using Multifunctional Nanoparticles

Molecular therapy using a small interfering RNA (siRNA) has shown promise in the development of novel therapeutics. Various formulations have been used for in vivo delivery of siRNAs. However, the stability of short double‐stranded RNA molecules in the blood and efficiency of siRNA delivery into target organs or tissues following systemic administration have been the major issues that limit applications of siRNA in human patients. In this study, multifunctional siRNA delivery nanoparticles are developed that combine imaging capability of nanoparticles with urokinase plasminogen activator receptor‐targeted delivery of siRNA expressing DNA nanocassettes. This theranostic nanoparticle platform consists of a nanoparticle conjugated with targeting ligands and double‐stranded DNA nanocassettes containing a U6 promoter and a shRNA gene for in vivo siRNA expression. Targeted delivery and gene silencing efficiency of firefly luciferase siRNA nanogenerators are demonstrated in tumor cells and in animal tumor models. Delivery of survivin siRNA expressing nanocassettes into tumor cells induces apoptotic cell death and sensitizes cells to chemotherapy drugs. The ability of expression of siRNAs from multiple nanocassettes conjugated to a single nanoparticle following receptor‐mediated internalization should enhance the therapeutic effect of the siRNA‐mediated cancer therapy.     

Composition of gallstones in Coimbatore District of Tamil Nadu State

BACKGROUND: Gallstones in northern India are predominantly of the cholesterol type; such information on gallstones in southern India is scant. AIM: To analyze the composition of gallstones from patients residing in Coimbatore District in Tamil Nadu State. METHODS: The stones were classified using the Bernhoft criteria and was correlated with the morphological characteristics. RESULTS: Of the 105 gallstones analyzed, 67 (63.8%) were of the pigment variety and 36 (34.8%) of the intermediate/mixed type. There were only two cholesterol stones. The mean proportions of cholesterol, bilirubin and calcium in the pigment and intermediate stones were 7.1%, 26.1% and 7.8% and 30.2%, 18.4% and 6.3%, respectively. The mean proportion of bilirubin in the pigment stones was higher than in the intermediate type. Morphologically, pigment stones were black in 55% and amorphous in 63%; the intermediate stones were hard in 50% and of variegated color ranging from yellow to ivory white in 61%; both cholesterol stones were multiple, hard and brown. CONCLUSIONS: There is a predominance of pigment and intermediate gallstones (98%) in this district. These stones have reduced cholesterol and an increase in bilirubin and calcium proportions.     

Investigation of Mechanical and Wear Behaviour of Al7075/SiC Composites Using Response Surface Methodology

Silicon - This work studies the effect of reinforcement weight percentage (Wt.%SiC) on wear and mechanical behaviour of the aluminium 7075 composites produced by the powder metallurgy technique....     

An early congestion feedback and rate adjustment schemes for many-to-one communication in cloud-based data center networks

Cloud data centers are playing an important role for providing many online services such as web search, cloud computing and back-end computations such as MapReduce and BigTable. In data center network, there are three basic requirements for the data center transport protocol such as high throughput, low latency and high burst tolerance. Unfortunately, conventional TCP protocols are unable to meet the requirements of data center transport protocol. One of the main practical issues of great importance is TCP Incast to occur many-to-one communication sessions in data centers, in which TCP experiences sharp degradation of throughput and higher delay. This important issue in data center networks has already attracted the researchers because of the development of cloud computing. Recently, few solutions have been proposed for improving the performance of TCP in data center networks. Among that, DCTCP is the most popular protocol in academic as well as industry areas due to its better performance in terms of throughput and latency. Although DCTCP provides significant performance improvements, there are still some defects in maintaining the queue length and throughput when the number of servers is too large. To address this problem, we propose a simple and efficient TCP protocol, namely NewDCTCP as an improvement of DCTCP in data center networks. NewDCTCP modified the congestion feedback and window adjusting schemes of DCTCP to mitigate the TCP Incast problem. Through detailed QualNet experiments, we show that NewDCTCP significantly outperforms DCTCP and TCP in terms of goodput and latency. The experimental results also demonstrate that NewDCTCP flows provide better link efficiency and fairness with respect to DCTCP.     

The validity of self-reported seatbelt use in a country where levels of use are low

The validity of self-reported seatbelt use among low belt use populations in low belt use countries has not been evaluated directly. Nine hundred and ninety drivers were recruited from shopping centers, car parks, and other suitable locations located in Afyon and Ankara cities of Turkey in order to compare the self-reported and observed seatbelt usage rates. Data sets were collected simultaneously from the participants not being aware of having their seatbelt use observed. Participants interviewed in Afyon (n = 301) and Ankara (n = 658) reported seatbelt usage (“always using a seatbelt”) rates of 39% and 45%, respectively. When observed, however, only 47% in Afyon and 70% in Ankara of these drivers actually fasten their seat-belts. It seems that the drivers in both cities exaggerated their use seat belts considerably.