Coriander (<Emphasis Type="Italic">Coriandrum sativum</Emphasis> L.) seed oil improves plasma lipid profile in rats fed a diet containing cholesterol

Coriander (Coriandrum sativum L.) seed oil (COR) is a promising oil with high levels of bioactive compounds. Very little information, however, is available on the effect of administration of COR on different aspects of plasma lipid profile in experimental animals. In view of the important implications, the effect of administration of COR and oil blend [a mixture of soybean oil, coriander oil and sunflower oil (4:2:4, w/w/w; Blend)] on the profile of plasma lipids was investigated in 24 male albino rats placed on a cholesterol-rich (1%) basal diet as compared to rats on a cholesterol-free basal diet. Coriander seed oil and Blend were analyzed for composition of fatty acid, sterol and tocopherol. The levels of bioactive compounds (sterols and tocopherols) were higher in COR than in the Blend. In addition, the antiradical potential of COR and Blend was measured and the results showed that COR had stronger radical scavenging activity than Blend. In the biological experiment, rats were divided into four diet groups. The negative control group (control) consumed the basal diet (BD) only, which contained wheat starch, casein and cellulose, as well as mineral and vitamin mixtures. To the BD were added 1 g/100 g cholesterol (Chol/group), or both (Chol/COR group) and (Chol/Blend group). The groups did not differ before the experiment, which lasted 60 days. Plasma total lipids (TL), triacylglycerols (TAG), total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C) and high-density lipoprotein-cholesterol (HDL-C) were measured at day 15, 30, 45 and 60 during the experiment period. Generally, COR and Blend-supplemented diets decreased the levels of TL, TC, TAG and LDL-C in plasma. In addition, significant increase in the levels of HDL-C was observed for Chol/COR and Chol/Blend groups. The results demonstrated that COR, and to a relatively lesser degree Blend, have hypocholesterolemic properties in rats fed a cholesterol-rich diet.     

Thermal analysis of ME—TVC+MEE desalination systems

Thermal analysis of three different configurations of a multi-effect thermal vapor compression desalting system is presented: conventional ME—TVC,ME—TVC with regenerative feed heaters (ME—TVC,FH) and ME—TVC coupled with a conventional MEE system (ME—TVC+MEE). The analysis is based on the First and Second Law of Thermodynamics. A parametric study was carried out to investigate the impact of motive steam pressure, temperature difference per effect, top brine temperature, feed seawater temperature and motive steam flow rate on the system's performance for each configuration. The exergy analysis showed that irreversibilities in the steam ejector and evaporators are the main sources of exergy destruction in the three configurations. When steam is supplied directly from the boiler to all configurations, results showed that the first effect was responsible for about 50% of the total effect exergy destruction. The study also showed that the decrease in exergy destruction is more pronounced than the decrease in the gain ratio at lower values of motive steam pressure. Lowering the temperature difference across the effects, by increasing the surface area, decreases the specific heat consumption. On the other hand, exergy losses are small at low temperature differences and low top brine temperature. The analysis showed that the third configuration (ME—TVC+MEE) has two main features compared to ME—TVC and ME—TVC, FH. First it has a lower compression ratio, which makes the motive steam capable of compressing larger amounts of the entrained vapor; as a result, the amount of motive steam is reduced. Second, the configuration can be used for large-scale production.     

MOF-derived bimetallic NiCo nanoalloys for the hydrogenation of biomass-derived levulinic acid to γ-valerolactone

The selective hydrogenation of biomass-derived levulinic acid (LA) to γ-valerolactone (GVL) is one of pivotal reactions in many of the biorefinery schemes for the production of value-added chemicals and biofuels. Herein, we have fabricated carbon-supported bimetallic NiCo catalysts based on the metal–organic framework (MOF) material via a pyrolysis method. The as-obtained Ni₁Co₁ bimetallic catalyst outperforms monometallic counterparts in the catalytic performance of LA-to-GVL, with a nearly full conversion of LA and a GVL yield of 95.2%, in particular with an excellent catalyst stability up to seven consecutive runs at 160°C and 4 MPa H₂. Based on a combined characterization study by employing advanced techniques, for example, extended x-ray absorption fine structure (EXAFS), high-angle annular dark-field scanning transmission electron microscopy (HADDF-STEM), and electron paramagnetic resonance (EPR), we reveal that the enhanced catalytic performance, in particular the excellent stability, could be attributed to the formation of the bimetallic alloys, which efficiently alleviates the metal leaching and sintering during catalysis.     

Phase-Field Modeling of Sigma-Phase Precipitation in 25Cr7Ni4Mo Duplex Stainless Steel

Phase-field modeling is used to simulate the formation of sigma phase in a model alloy mimicking a commercial super duplex stainless steel (SDSS) alloy, in order to study precipitation and growth of sigma phase under linear continuous cooling. The so-called Warren–Boettinger–McFadden (WBM) model is used to build the basis of the multiphase and multicomponent phase-field model. The thermodynamic inconsistency at the multiple junctions associated with the multiphase formulation of the WBM model is resolved by means of a numerical Cut-off algorithm. To make realistic simulations, all the kinetic and the thermodynamic quantities are derived from the CALPHAD databases at each numerical time step, using Thermo-Calc and TQ-Interface. The credibility of the phase-field model is verified by comparing the results from the phase-field simulations with the corresponding DICTRA simulations and also with the empirical data. 2D phase-field simulations are performed for three different cooling rates in two different initial microstructures. A simple model for the nucleation of sigma phase is also implemented in the first case. Simulation results show that the precipitation of sigma phase is characterized by the accumulation of Cr and Mo at the austenite-ferrite and the ferrite-ferrite boundaries. Moreover, it is observed that a slow cooling rate promotes the growth of sigma phase, while a higher cooling rate restricts it, eventually preserving the duplex structure in the SDSS alloy. Results from the phase-field simulations are also compared quantitatively with the experiments, performed on a commercial 2507 SDSS alloy. It is found that overall, the predicted morphological features of the transformation and the composition profiles show good conformity with the empirical data.

     

Assessment of groundwater resources in Kuwait using a finite difference model

Usable groundwater resources have strategic significance, given the arid climate of Kuwait. Assessment of groundwater resources through modelling is considered of paramount importance for sustained long‐term development of this resource. A conceptual model of the regional hydrogeology of the area has been developed based on the available data. Three aquifers were recognized within the Dammam Formation‐Kuwait Group sequence. VTDN software was used for numerical simulation of the groundwater flow in this aquifer system under steady‐state conditions. Calibration runs made to date suggest that the model is sensitive to the vertical coefficient of permeability of the aquitards and the horizontal transmissi‐vities of the aquifers. The water balance achieved shows that the contribution from the natural recharge from precipitation is insignificant.     

Towards SoC Validation Through Prototyping: A Systematic Approach Based on Reconfigurable Platform

Hardware/software covalidation is becoming one of the most critical issues in current System-on-Chip (SoC) design. Nowadays, covalidation is usually performed by cosimulation which is slow and lacks accuracy. The other alternative is to build a hardware prototype specific to the application. However, this alternative is expensive in terms of time, man-power, and cost. As SoCs increase in complexity, validation becomes more and more difficult, time consuming and error prone. Thus, a new approach for covalidation is inescapable. In this paper, we present a novel efficient prototyping approach for complex SoC covalidation. The proposed approach enables systematic prototyping of embedded applications on a reconfigurable platform. The process starts from the RT level model of the application. The application and the reconfigurable platform have to be adapted to obtain the prototype. We decompose the prototyping process into four steps, in order to match the application and the platform. Besides, we propose adapted solutions to deal with constraints typically encountered in existing reconfigurable platforms. The main advantages of this method are: fast and accurate validation, systematic prototyping flow, and large application field. Prototyping of a subset of VDSL using the ARM Integrator platform illustrates the effectiveness of our approach.     

Grid computing: a STOPE view

Grid computing is emerging as the foundation upon which virtual organizations can be built. Such organizations are becoming of increasing importance for tackling various projects, both in academic and in business fields. This paper is concerned with presenting an integrated view of the grid to readers interested in understanding it, or perhaps in developing it further or making use of it in the future. The target view is based on the STOPE (strategy/technology/organization/people/environment) framework that has previously been used to integrate the issues of various information technology problems over its well‐defined domains. For strategy, the view considers the reasons associated with the need for the grid, including grid services and grid benefits. For technology, the technical components of the grid and their functions are taken into account. For organization, the organizations concerned with the development, technology production, service provisioning and use of the grid are considered. For people, those associated with the grid in the related organizations are taken into account. For the environment, rules, practices and support associated with the grid are discussed. Finally, the paper emphasizes questions that need to be answered in order to contribute to the future development of the grid. Copyright © 2006 John Wiley & Sons, Ltd.