Experimental investigation of liquid-fuel atomization using Hartmann acoustic generator

The Hartmann acoustic generator has been used in the present experiments to atomize high-speed diesel oil, aviation kerosene and light furnace oil. The effects of upstream air pressure (196–490 kPa), nozzle diameter, and frequency of sound field (5000–22000 Hz) on the mean droplet size of the spray have been investigated. The experiments showed that the degree of fuel atomization was much more sensitive to a variation in the upstream air pressure than to a variation in the acoustic frequency. Atomization was almost independent of fuel viscosity; thus burners incorporating these acoustic generators should prove particularly suitable for the atomization and combustion of heavy fuel oils. It was dependent mainly on surface tension and fuel density. A single correlation has been obtained for all three fuels, within the range of experimental conditions investigated, but attempts to develop a dimensionless expression incorporating surface tension and density were unsuccessful, partly because of the small range of these properties examined.     

Building reliable MPLS networks using a path protection mechanism

It is expected that multiprotocol label switching (MPLS) based recovery could become a viable option for obtaining faster restoration than layer 3 rerouting. To deliver reliable service, however, MPLS requires a set of procedures to provide protection for the traffic carried on the label switched paths. We propose a path protection mechanism that is simple, scalable, fast, and efficient. We describe in detail our design considerations, the communication of fault information to appropriate switching elements, and the fault detection protocol. In particular, we propose a reverse notification tree structure for efficient and fast distribution of fault notification messages     

Kinetics of model high molecular weight organic compounds biodegradation in soil aquifer treatment

Soil Aquifer Treatment (SAT) is a process where treated wastewater is purified during transport through unsaturated and saturated zones. Easily biodegradable compounds are rapidly removed in the unsaturated zone and the residual organic carbon is comprised of primarily high molecular weight compounds. This research focuses on flow in the saturated zone where flow conditions are predictable and high molecular weight compounds are degraded. Flow through the saturated zone was investigated with 4 reactors packed with 2 different particle sizes and operated at 4 different flow rates. The objective was to evaluate the kinetics of transformation for high molecular weight organics during SAT. Dextran was used as a model compound to eliminate the complexity associated with studying a mixture of high molecular weight organics. The hydrolysis products of dextran are easily degradable sugars. Batch experiments with media taken from the reactors were used to determine the distribution of microbial activity in the reactors. Zero-order kinetics were observed for the removal of dextran in batch experiments which is consistent with hydrolysis of high molecular weight organics where extracellular enzymes limit the substrate utilization rate. Biomass and microbial activity measurements demonstrated that the biomass was independent of position in the reactors. A Monod based substrate/biomass growth kinetic model predicted the performance of dextran removal in the reactors. The rate limiting step appears to be hydrolysis and the overall rate was not affected by surface area even though greater biomass accumulation occurred as the surface area decreased.     

Reliability Modeling and Analysis of Computer Networks

The reliability analysis of computer communication networks is generally based on Boolean algebra and probability theory. This paper discusses various reliability problems of computer networks including terminal-pair connectivity, tree connectivity, and multi-terminal connectivity. This paper also studies the dynamic computer network reliability by deriving time-dependent expressions for reliability measures assuming Markov behavior for failures and repairs. This allows computation of task and mission related measures such as mean time to first failure and mean time between failures. A detailed analysis of the bridge network is presented.     

Enhanced Fluorescence for Bioassembly by Environment‐Switching Doping of Metal Ions

The self‐assembly of cyclodipeptides composed of natural aromatic amino acids into supramolecular structures of diverse morphologies with intrinsic emissions in the visible light region is demonstrated. The assembly process can be halted at the initial oligomerization by coordination with zinc ions, with the most prominent effect observed for cyclo‐dihistidine (cyclo‐HH). This process is mediated by attracting and pulling of the metal ions from the solvent into the peptide environment, rather than by direct interaction in the solvent as commonly accepted, thus forming an “environment‐switching” doping mechanism. The doping induces a change of cyclo‐HH molecular configurations and leads to the formation of pseudo “core/shell” clusters, comprising peptides and zinc ions organized in ordered conformations partially surrounded by relatively amorphous layers, thus significantly enhancing the emissions and allowing the application of the assemblies for ecofriendly color‐converted light emitting diodes. These findings shed light into the very initial coordination procedure and elucidate an alternative mechanism of metal ions doping on biomolecules, thus presenting a promising avenue for integration of the bioorganic world and the optoelectronic field.     

Hybrid Chameleon Search and Remora Optimization Algorithm-based Dynamic Heterogeneous load balancing clustering protocol for extending the lifetime of wireless sensor networks

Clustering is an indispensable strategy that helps towards the extension of lifetime of each sensor nodes with energy stability in wireless sensor networks (WSNs). This clustering process aids in sustaining energy efficiency and extended network lifetime in sensitive and critical real-life applications that include landslide monitoring and military applications. The dynamic characteristics of WSNs and several cluster configurations introduce challenge in the process of searching an ideal network structure, a herculean challenge. In this paper, Hybrid Chameleon Search and Remora Optimization Algorithm-based Dynamic Clustering Method (HCSROA) is proposed for dynamic optimization of wireless sensor node clusters. It utilized the global searching process of Chameleon Search Algorithm for selecting potential cluster head (CH) selection with balanced trade-off between intensification and extensification. It determines an ideal dynamic network structure based on factors that include quantity of nodes in the neighborhood, distance to sink, predictable energy utilization rate, and residual energy into account during the formulation of fitness function. It specifically achieved sink node mobility through the integration of the local searching capability of Improved Remora Optimization Algorithm for determining the optimal points of deployment over which the packets can be forwarded from the CH of the cluster to the sink node. This proposed HCSROA scheme compared in contrast to standard methods is identified to greatly prolong network lifetime by 29.21% and maintain energy stability by 25.64% in contrast to baseline protocols taken for investigation.