A hierarchical approach for the synthesis of batch water network

This work addresses the problem of synthesising cost-effective batch water networks where a number of process sources along with fresh water are mixed, stored, and assigned to process sinks. In order to address the complexity of the problem, a three-stage hierarchical approach is proposed. In the first stage, global targets are identified by formulating and solving a linear transportation problem for minimum water usage, maximum water recycle, and minimum wastewater discharge. These targets are determined a priori and without commitment to the network configuration. Next, a network with minimum number of tanks is synthesised by solving a mixed-integer non-linear program. The bilinear constraints are relaxed to transform the program into a mixed-integer linear program that is globally solvable. The third stage is aimed at simplifying the network configuration by minimising the number of network inter-connections. Insights gained from the water pinch analysis are also incorporated into the approach to further reduce the water flows via the placement of water regeneration unit. A case study is solved to illustrate the effectiveness of the proposed procedure.     

Synthesis and structure of [{As(NBu)3}2Li6] containing an [As(NBu)3] trianion

Attempts to prepare the [As(N^tBu)₃]³⁻ trianion by the reaction of As(NMe₂)₃ with [^tBuNHLi]_n (1:3 monomer equiv.) proved unsuccessful. However, if the reaction is carried out with an excess of ^tBuNH₂ (3 equiv.) the target complex [{As(N^tBu)₃}₂Li₆] (1) is obtained. This is the first example of a complex containing an [As(NR)₃]³⁻ trianion.     

Changes in membrane fatty acids and murein composition of Bacillus cereus and Salmonella Typhi induced by gamma irradiation treatment

This present study was carried out to evaluate the effects of gamma irradiation on the fatty acids (FA) and mureins composition of two different radiotolerant bacteria. Bacillus cereus LSPQ 2872 and Salmonella Typhi ATCC 19430 were used for this study. The bacterial strains were treated with a sublethal radiation dose of 1 kGy to cause a cellular damage. Gas chromatography (GC) and high performance liquid chromatography (HPLC) analysis were performed to demonstrate respectively the modification of the FA composition and the changes in muropeptide profile. Results obtained show, for both bacteria, that this treatment had a significant effect (P ≤ 0.05) on the FA content with an increase of unsaturated FA percentage. Substantial changes were also noticed for the relative percentage and the number of the muropeptides. This study represents one of the few to demonstrate the modifications on bacterial membrane as a cellular response to survive the ionising radiation stress.     

Simultaneous contrast: Evidence from licking microstructure and cross-solution comparisons.

The microstructure of rats' licking responses was analyzed to investigate both “classic” simultaneous contrast (e.g., Flaherty & Largen, 1975) and a novel discrete-trial contrast procedure where access to an 8% test solution of sucrose was preceded by a sample of either 2%, 8%, or 32% sucrose (Experiments 1 and 2, respectively). Consumption of a given concentration of sucrose was higher when consumed alongside a low rather than high concentration comparison solution (positive contrast) and consumption of a given concentration of sucrose was lower when consumed alongside a high rather than a low concentration comparison solution (negative contrast). Furthermore, positive contrast increased the size of lick clusters while negative contrast decreased the size of lick clusters. Lick cluster size has a positive monotonic relationship with the concentration of palatable solutions and so positive and negative contrasts produced changes in lick cluster size that were analogous to raising or lowering the concentration of the test solution respectively. Experiment 3 utilized the discrete-trial procedure and compared contrast between two solutions of the same type (sucrose-sucrose or maltodextrin-maltodextrin) or contrast across solutions (sucrose-maltodextrin or maltodextrin-sucrose). Contrast effects on consumption were present, but reduced in size, in the cross-solution conditions. Moreover, lick cluster sizes were not affected at all by cross-solution contrasts as they were by same-solution contrasts. These results are consistent with the idea that simultaneous contrast effects depend, at least partially, on sensory mechanisms. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Effect of processing variables and bulk composition on the surface composition of spray dried powders of a model food system

The surface compositions of food powders created from spray drying solutions containing various ratios of sodium caseinate, maltodextrin and soya oil have been analysed by Electron Spectroscopy for Chemical Analysis. The results show significant enrichment of oil at the surface of particles compared to the bulk phase and, when the non-oil components only are considered, a significant surface enrichment of sodium caseinate also. The degree of surface enrichment of both oil and sodium caseinate was found to increase with decreasing bulk levels of the respective components. Surface enrichment of oil was also affected by processing conditions (emulsion drop size and drying temperature), but surface enrichment of sodium caseinate was relatively insensitive to these. The presence of “pock marks” on the particle surfaces strongly suggests that the surface oil was caused by rupturing of emulsion droplets at the surface as the surrounding matrix contracts and hardens.     

Epitaxial Thin Film Growth of Lanthanum and Neodymium Aluminate Films on Roll-Textured Nickel Using a Sol-Gel Method

As part of an effort to develop a new, non-vacuum-processed substrate for high current superconducting films, thin films of LaAlO₃ and NdAlO₃ were deposited on biaxially textured (100) nickel substrates using a solution deposition technique. On heating to 1150°C in Ar-4% H₂ for 1 h, epitaxial films were obtained. Out-of-plane alignment was confirmed by obtaining rocking curves of the (002) plane of the LaAlO₃ (full width at half-maximum (fwhm) = 7.2°) and the NdAlO₃ (fwhm = 5.8°) films. In-plane alignment was demonstrated by obtaining phi scans of the (110) plane of the LaAlO₃ (fwhm = 13.4°) and the NdAlO₃ (fwhm = 8.8°) films. Grain alignment in the films is approximately equivalent to the alignment of the Ni substrate. Analysis of pole figures indicated that in both films there are two in-plane orientations present, the major being (001)[100] and the minor (001)[110].     

Energy sector planning using multiple-index pinch analysis

Pinch analysis was initially developed as a methodology for optimizing energy efficiency in process plants. Applications of pinch analysis applications are based on common principles of using stream quantity and quality to determine optimal system targets. This initial targeting step identifies the pinch point, which then allows complex problems to be decomposed for the subsequent design of an optimal network using insights drawn from the targeting stage. One important class of pinch analysis problems is energy planning with footprint constraints, which began with the development of carbon emissions pinch analysis; in such problems, energy sources and demands are characterized by carbon footprint as the quality index. This methodology has been extended by using alternative quality indexes that measure different sustainability dimensions, such as water footprint, land footprint, emergy transformity, inoperability risk, energy return on investment and human fatalities. Pinch analysis variants still have the limitation of being able to use one quality index at a time, while previous attempts to develop pinch analysis methods using multiple indices have only been partially successful for special cases. In this work, a multiple-index pinch analysis method is developed by using an aggregate quality index, based on a weighted linear function of different quality indexes normally used in energy planning. The weights used to compute the aggregate index are determined via the analytic hierarchy process. A case study for Indian power sector is solved to illustrate how this approach allows multiple sustainability dimensions to be accounted for in energy planning.     

Use of Impedance Probe for Estimation of Porosity Changes in Saturated Granular Filters under Cyclic Loading: Calibration and Application

Gravimetric and volumetric sampling techniques are reliable for the measurement of porosity in fully saturated granular filters. However, both methods require a significant effort to gather and prepare samples, are time intensive to process, and do not capture real-time changes. Portable impedance probes serve as a valuable alternative to these destructive and laborious sampling methods. These probes measure the dielectric properties of the soil-water mixtures from which the porosity of filters may be inferred. This study demonstrates that generalized calibrations can result in large errors for porosity estimation when using diverse and small-scale filter types. By comparing with gravimetric and volumetric based porosity measurements for saturated granular filter porosity, impedance probes with filter-specific calibration offer the reliability and confidence owing to its reduced error in a quick, nondestructive fashion. This paper also presents the results of a laboratory investigation using an impedance probe to monitor real-time changes in the porosity of saturated granular filters subjected to cyclic train loading.