Amino acid bound surfactants: a new synthetic family of polymeric monoliths opening up possibilities for chiral separations in capillary electrochromatography

By combining a novel chiral amino-acid surfactant containing an acryloyl amide tail, a carbamate linker, and a leucine headgroup of different chain lengths with a conventional cross-linker and a polymerization technique, a new "one-pot" synthesis for the generation of amino-acid based polymeric monolith is realized. The method promises to open up the discovery of an amino-acid based polymeric monolith for chiral separations in capillary electrochromatography (CEC). The possibility of enhanced chemoselectivity for simultaneous separation of ephedrine and pseudoephedrine containing multiple chiral centers and the potential use of this amino-acid surfactant bound column for CEC and CEC coupled to mass spectrometric detection are demonstrated.     

A simple programmable frequency meter for low frequencies withknown nominal values

A meter which can be used to measure instantaneously the frequencies of various signals, such as power line frequencies, heart rates, and motor speeds, by only choosing the proper clock and nominal frequencies is described. The technique is based on using an up/down counter operating in the down mode only, resulting in minimum timing signals. Thus the meter is designed with a minimum number of digital integrated circuits. Two frequency meters for heart rate and power line frequency measurements are discussed. A prototype of the proposed meter is built and tested for various frequencies     

Furazolidone treatment suppresses pubertal testosterone secretion in male broiler breeder birds (Gallus domesticus)

We determined the effect of chronic administration of furazolidone (Fz) on sexual maturation of male broiler breeder birds (Ross 308; Gallus domesticus). A total of 20 15-w-old birds were randomly assigned to receive 0, 150, 250 or 350 mg Fz/kg feed daily for 5-w. Blood samples were taken at weekly intervals. The birds were challenged with 500 IU human chorionic gonadotropin (hCG) i.v. at the age of 24 w before slaughtering. Concentration of testosterone in the plasma was measured by a specific radioimmunoassay. Testicular tissue was processed for morphometric studies. Testicular weights of the groups fed 250 or 350 mg Fz/kg feed/d were decreased (P < 0.05). Plasma testosterone levels were affected by age (P < 0.001) and dose of Fz (P < 0.001). Mean plasma testosterone levels during and after drug administration were reduced (P < 0.05) by all Fz doses. Human chorionic gonadotropin administration led to poor testosterone response (P < 0.05) in all Fz-dosed groups, but not the control group (P < 0.05). As compared to the control, Fz-dosing reduced the seminiferous tubule diameter (P < 0.05) at the 350 mg/kg feed dose, seminiferous epithelial height (P < 0.05) at the 250 and 350 mg/kg feed doses, and Leydig cell nuclear diameter (P < 0.05) at the 350 mg/kg feed dose. This data suggest that sexual maturation in male broiler breeder birds is adversely affected by chronic Fz-administration. Actions of Fz on sexual maturation probably involve a direct effect at the testicular level.     

Performance study of a heat pump dryer system for specialty crops—Part 1: Development of a simulation model

This research is concerned with the technology of heat pump assisted drying of specialty crops. A simplified procedure for modelling the performance of a low temperature heat pump dryer was developed. The system modelled consists of a vapour compression heat pump coupled to a continuous cross flow bed dryer. The model takes into account the detailed heat and mass transfer phenomena taking place in the heat pump and dryer circuits. Copyright © 2002 John Wiley & Sons, Ltd.     

Thermophysical interface properties of crude oil and aqueous solution containing sulfate anions: experimental and modeling approaches

Abstract

Sulfate anion is well-known for being one of the most active agents to be injected into the oil reservoirs and being capable of not only altering the interfacial properties of crude oil but also enhancing the water solution properties in oil recovery. In the current study, the effects of temperature and pressure were studied on interfacial tension (IFT) as well as the adsorption behavior of two different solutions containing sulfate anion using experimental measurements and modeling approaches. Although it was expected that IFT values of the studied systems might decrease as temperature increased due to the improvement in the molecule mobility and solubility of crude oil in water, which consequently might lead to the reduction in its free energy, the reverse trend was observed. The measured dynamic IFT values and adsorption behavior revealed that surface excess concentration of natural surfactants (Г_NS) can be considered as the most effective parameter on interpreting IFT behavior as a function of temperature.     

Prediction of asphaltene deposition during turbulent flow using heat transfer approach

In this study, asphaltene deposition from crude oil has been studied experimentally using a test loop and prediction using theoretical study under turbulent flow (Reynolds numbers below 5000). The effects of many parameters such as oil velocity, surface temperature and concentration of flocculated asphaltene on the asphaltene deposition were investigated. The results showed that asphaltene deposition thickness increases with increasing both surface temperature and concentration of flocculated asphaltene and decreasing oil velocity. Thermal approach was used to describe the mechanisms involved in this process and the results of data fitting showed that there are good agreements between the results of the proposed model and the measured asphaltene deposition rates.     

Texture/phase evolution during microwave fabrication of nanocrystalline multicomponent (Cu/Zn/Al)O metal oxides with varying diethylene glycol content applied in hydrogen production

A series of Cu/Zn/Al mixed oxides, as steam methanol reforming catalysts, were synthesized via the microwave assisted combustion synthesis method using diethylene glycol as the organic fuel. The nanocatalysts were analyzed by XRD, FESEM, EDX, BET, H₂-TPR and FTIR techniques to ensure authenticity of the synthesis steps and pursuing the effect of the fuel/nitrate ratio on their physicochemical properties. The results proved the necessity of defining an optimum fuel/nitrate ratio for the combustion synthesis method. Fuel/nitrate ratio affects significantly on crystal growth and crystalline facets size. Proper crystallography of CuO/ZnO/Al₂O₃ (DEG/Nitrate = 3) nanocatalyst along with higher specific surface area and distributed particle size, made it predictable that it could result in higher methanol conversion in the steam methanol reforming process. The catalytic performance studies justified assumptions, since the CZA (DEG/N = 3) presented higher methanol conversion and selectivity toward desired products as well as its high stability.     

Focal distraction: Spatial shifts of attentional focus are not required for contingent capture.

Contingent capture occurs when distractors that share the target's defining attribute capture attention and slow down target identification. This slowdown has been attributed to an involuntary attentional shift to the location of a pertinent distractor. The present study examined an additional source of delay: the time spent in processing pertinent distractors. In 7 experiments, distractors were presented at fixation, and targets were presented either at fixation or peripherally. Contingent capture invariably occurred when a salient distractor was presented within about 600 ms before the target, even when spatial shifts in attentional focus were ruled out. A 2-stage model is proposed in which stimuli must pass an input filter tuned to the target's defining attribute before gaining access to a high-level stage that is unavailable while a distractor is being processed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Monitoring and Evaluation Scheme using the Multiple-Criteria-Decision-Making Technique: Application to Irrigation Projects

The application of monitoring and evaluation (M&E) systems to assess agricultural projects has received some attention in recent years. These systems provide valuable information for managers and decision makers by analyzing the implementation process, the progress of trends, and the long-term and short-term effectiveness of these projects. An algorithm is developed to monitor and evaluate drip and pressure irrigation projects in Iran. Different indicators are identified and the framework of an integrated evaluation system is demonstrated using an analytical hierarchy process for multiple-criteria-decision making. There is much subjective information that is quantified and normalized in order to remove any bias in evaluators’ assessment of qualitative measures or sensitivity to linguistic expressions. The application of this system to rank projects in different regions (zones) in Iran is also presented in this paper. The results have shown the significant value of such systems in providing information and input for different decision-making levels.