Long-term energy scenarios for Mexico: Policy options for carbon savings and main barriers

This paper shows that possibilities exist for maintaining current energy-related carbon emissions per capita in Mexico at almost constant levels in the long term. It is argued, however, that the identified carbon emissions reductions will not be achieved easily or rapidly, as they require a restructuring of Mexico's current technological base and an unusual degree of coordination among the government, lending institutions, equipment manufacturers, and final users. Such changes also will entail surmounting major institutional and financial barriers and creating a better international environment for technology transfer and capital lending.     

MICROSTRUCTURE AND FATIGUE PROPERTIES OF A WELDED DUPLEX STAINLESS STEEL

Abstract— In response to the increasing structural applications in duplex steels for welded structures, fatigue behaviour of a SAF 2304 grade duplex stainless steel was investigated, considering both the base metal and GTAW welded joints. Fatigue curves and fatigue limits under rotary bending fatigue were obtained. The study focused attention on the microstructural features of fatigue crack propagation of the two series of experiments, thereby permitting an evaluation of the tortuous crack path of welded joints and the mechanisms related to threshold microstructural barriers.     

Characterization of hollow fiber membranes in a permeator using binary gas mixtures

We have studied the CO₂/CH₄ mixed gas permeation through hollow fiber membranes in a permeator. An approach to characterize the true separation performance of hollow fiber membranes for binary gas mixtures was provided based on experiments and simulations. Experiments were carried out to measure the retentate and permeate flow rates and compositions at each outlet. The influences of pressure drop within the hollow fibers, non-ideal gas behavior in the mixture and concentration polarization were taken into consideration in the mathematics model. The calculation results indicate that the net influence of the non-ideal gas behavior, competitive sorption and plasticization yields the calculated CO₂ permeance in a mixed gas permeator close to that obtained in pure gas tests. Whereas the CH₄ permeance is higher in the mixed gas tests than that in the pure gas tests, as the plasticization caused by CO₂ dominates the permeation process. As a result, the CO₂/CH₄ mixed gas selectivity is smaller than those obtained in pure gas tests at equivalent pressures.The calculated membrane performance shows little changes with stage cut if the effect of concentration polarization is accounted for in the calculation. The integration method developed in this study could provide more accurate characterizations of mixed gas permeance of hollow membranes than other estimation methods, as our model considers the roles of non-ideal gas behavior and concentration polarization properly.     

Inter- and intra-molecular ionic interactions of polyampholyte: Carboxymethyl-2-diethylaminoethylcellulose

Carboxymethyl-2-diethylaminoethylcellulose (CM-DEAE cellulose) was prepared by etherification of carboxymethylcellulose with diethylaminoethyl chloride in a NaOH solution. The behaviour of CM-DEAE cellulose in aqueous solution was studied by viscosity and GPC measurements. The degree of substitution (DS) and existing states of DEAE substituents were examined by the use of proton NMR, and those of the CM substituents were observed with FT-IR. The results reveal that the reduced viscosity and apparent molecular size of CM-DEAE cellulose vary with the concentration of sodium chloride and changes in pH and DS. These phenomena can be explained in terms of inter- and intra-molecular ionic interactions.     

地下水污染修复的活性渗滤墙技术

活性渗滤墙是一种现场修复受污染地下水的新型技术，具有原理简单，施工方便，运行费用低廉等特点，活性渗滤墙垂直于地下水流动方向设置，当地下水流通过活性渗滤墙时，污染物与墙体材料发生化学反应，从而达到环境修复的目的。文中综述了活性渗滤墙技术的修复机理和实际应用，大量研究表明，应用金属铁作为活性渗滤墙材料，可以去除地下水中的重金属以及有机污染物，目前活性渗滤墙已经在世界各地应用，是一种非常有发展前景的环境污染修复技术。     

Evidence-Based Solutions for Overcoming Access Barriers, Decreasing Attrition, and Promoting Change With Underserved Families.

Various definitions exist for what constitutes family therapy. In this article, we consider family therapy to encompass any intervention that targets family interactions and conceptualizes problems as existing beyond individual clients. Numerous individual studies and several quantitative reviews have established family therapy as an effective treatment modality and the treatment of choice for many disorders. However, critiques of existing service provision highlight the unfortunate fact that numerous barriers to treatment exist at multiple levels of the broader ecology, preventing many families from benefiting from these services. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

New intramolecular effect observed for polyesters: An anomeric effect

A series of polyesters was prepared to evaluate hydrolytic stability as a function of cyclohexyl dibasic acid content. The three cyclohexyl dibasic acids: 1,2; 1,3; and 1,4 were formulated into polyesters with two glycols. The proportion of cis and trans isomers was evaluated via ¹H NMR. The hydrolytic stability of short chain polyesters was evaluated in an acetone/water mixture which solubilized the polyesters to mimic oligoester behavior within a thermosetting polyester coating environment. The rate of hydrolysis was monitored by acid titration and corroborated by GPC. Surprisingly, 1,2-cylohexyl diacid-based polyesters were robust, and 1,3-cyclohexyl diacid-based polyesters were the most susceptible to hydrolysis. Evidently, a 1,2-anchimeric effect for cyclohexyl dibasic acid polyesters was not an important consideration, while the 1,3-cyclohexyl ester interaction was. Consequently, an anomeric effect was proposed. Presented at the 81st Annual Meeting of the Federation of Societies for Coatings Technology, November 12–14, 2003, in Philadelphia, PA.     

Gas transport in poly(n-alkyl acrylate)/poly(m-alkyl acrylate) blends

Poly(n-alkyl acrylate)s can have side chains that crystallize independently of the main chain; side-chain length can thus be used as a tunable parameter to control the gas permeability of membranes. The gas permeation response of poly(n-alkyl acrylate) and poly(m-alkyl acrylate) blends as a function of temperature is reported for varying side-chain lengths, n and m, and blend composition in the semi-crystalline and molten states. Macroscopic homogeneity is observed for a small range of n and m where |n − m| ≤ 2-4 methylene units. Thermal analysis indicates that the blend components crystallize independently of one another; however, crystallization is hindered by the presence of the other component. Permeation responses of the blends investigated in some cases exhibited two distinct permeation jumps or increases at the melting temperature of each component. Blends with continuous permeation responses but higher effective activation energies of permeation (i.e., more thermally responsive) were observed for some blends over the temperature of interest for membranes to be used for modified atmosphere packaging.     

Effects and properties of poly(arylene ether benzonitrile)s of various molecular weights blended with sulfonated poly(ether ether ketone)

Poly(arylene ether benzonitrile) (PAEBN) was synthesized with 2,6‐dichlorobenzonitrile and biphenol. PAEBNs with various molecular weights (MWs), 1,640,000 and 185,000 g/mol, were synthesized by control of the stoichiometry of the monomers and were blended with sulfonated poly(ether ether ketone) (SPEEK). The effects of MW on the water uptake, swelling, methanol permeability, and proton conductivity of the SPEEK/PAEBN blend membranes were investigated. The molecular mobility of the SPEEK/PAEBN blends was also examined in this study. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Perceived employment barriers and their relation to workforce-entry intent among people with HIV/AIDS.

As treatments have improved health and quality of life for people with HIV/AIDS, many have contemplated workforce reentry. Workforce reentry rarely occurs among people with illness-related disability. The authors mailed a survey that included workforce-entry-related concerns to 1,991 HIV/AIDS clients. Factor analysis extracted 6 areas of concern (benefits loss, work-related health, job skills, discrimination, personal health care, workplace accommodation). Levels of concern generally increased with HIV acuity level and time since last worked. Work-related health concerns predicted consideration of workforce entry, and work-related health concerns and benefits-loss concerns predicted estimated time to return to work. Findings provide quantitative validation of intuitive categories of workforce-entry concerns among people with HIV/AIDS and suggest that concerns may shift with progress toward workforce entry. (PsycINFO Database Record (c) 2010 APA, all rights reserved)