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Alternative Technologies (alternative + technology)
Selected AbstractsAlternative technologies for biotechnological fuel ethanol manufacturingJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2007Alain A Vertès Abstract The challenges of implementing biorefineries on a global scale include socioeconomic, financial, and technological constraints. In particular, the development of biorefineries is tightly linked to the continued availability of fermentation raw materials. These constraints can be relaxed by the use of diverse raw materials, while advances that confer higher flexibility would enable biotechnological plant managers to swiftly react to volatile markets. In conventional processes, Saccharomyces cerevisiae grows on a relatively limited range of substrates, and produces only a single product,ethanol. Given the observed maturity of the S. cerevisiae fermentation technology, alternatives to baker's yeast may be needed to tip the economic balance in favour of biotechnological ethanol. These alternative fermentation technologies may allow a greater diversity of substrates to be used to produce an individually tailored mix of ethanol and other chemicals. Copyright © 2007 Society of Chemical Industry [source] Identifying and overcoming the potential barriers to the adoption of natural orifice transluminal endoscopic surgeryASIAN JOURNAL OF ENDOSCOPIC SURGERY, Issue 2 2010S. D. Schwaitzberg Abstract Natural orifice translumenal endoscopic surgery (NOTES) is an emerging innovative approach to performing minimally invasive surgical procedures. In its full potential, the concept of incisionless surgery will have mass appeal to patients. However, the barriers to adopting NOTES will have to be overcome before widespread acceptance of these techniques can occur. These potential barriers include infection, visceral leakage, difficulties in tissue manipulation, and increased cost. The history of surgical innovation has continuously overcome similar problems in other settings, and all of these potential obstacles are likely solvable. Training surgeons will be an additional barrier that will need to be overcome, but this obstacle will need to be approached differently than when laparoscopy was introduced, as standards are higher today for privileging and credentialing in most hospitals than 20 years ago. Alternative technologies that were not adopted prior to the introduction of NOTES may now appear more viable making the competitive environment more complex. Increased funding for comparative effectiveness studies and training for competency in innovation will also need original solutions, but are clearly in our patients' best interest. [source] Cryogenic condensation: A cost-effective technology for controlling VOC emissionsENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 2 2002Robert J. Davis Cryogenic condensation is an extremely cost-effective technology for controlling emissions of Volatile Organic Compounds (VOCs) from chemical processing facilities under certain conditions. This paper describes the technology and provides the case history of an application in the pharmaceutical industry, in which its cost effectiveness was compared with a range of alternative technologies, including thermal oxidation, catalytic oxidation, flaring, carbon adsorption, and scrubbing. Because the facility already used significant quantities of liquid and gaseous nitrogen for inerting, blanketing, and purging, a very convenient cold source for cryogenic condensation was already present. On a lifetime cost basis, cryogenic condensation was significantly less costly than all other technologies evaluated. [source] An Evaluation of Physicochemical Treatment Technologies for Water Contaminated with MTBEGROUND WATER MONITORING & REMEDIATION, Issue 4 2000Arturo A. Keller Treatment of methyl tertiary-butyl ether (MTBE) from contaminated surface and ground water supplies presents specific challenges due to the physicochemical properties of MTBE that depend strongly on its hydrophilic nature, and translate into a high solubility in water, and low Henry's constant and low affinity for common adsorbents. We evaluate four treatment technologies-air stripping, granular activated carbon (GAC), hydrophobic hollow fiber membranes, and advanced oxidation processes (AOP)-using ozone or ozone/hydrogen peroxide. Experimental work was carried out to generate parameter values necessary for the design of these processes. Ten different flow rates/concentration combinations were evaluated in our designs to cover the range from high flow rate/low concentration typical of surface water and ground water drinking water supplies to low flow rate/high concentration typical of ground water remediation sites. For all cases, the processes were designed to produce effluent water of 5 ,g/L or less. Capital costs and operation and maintenance costs were determined at the feasibility level by using standard engineering estimating practices. Air stripping is the lowest cost technology for high flow rales (100 to 1000 gpm) if no air treatment is required. Hollow fiber membranes are the lowest cost technology for flow rates of 10 to 100 gpm if no air treatment is required, which is typical at these low flow rates. GAC will be most costeffective at all flow rates if air treatment is required and the influent water has low levels of other organic compounds. AOP using ozone or ozone/hydrogen peroxide is in all cases more expensive than the alternative technologies, and there are sufficient uncertainties at this point with respect to byproducts of AOP to warrant further study of this technology. The cost of treating MTBE-contaminated water for conventional technologies such as air stripping and GAC is 40% to 80% higher than treating water contaminated only with other hydrocarbons such as benzene. [source] Economic theory and nuclear energyOPEC ENERGY REVIEW, Issue 2 2000Ferdinand E. Banks The economics literature dealing with nuclear energy and uranium is inadequate, and several extremely important topics deserve a more methodical treatment. This survey provides: an alternative derivation for the optimal mix of generating capacity; a systematic but essentially non-technical approach to the nuclear fuel cycle; some comments on alternative technologies; and a stock-flow analysis of the market for uranium. It is also argued: that existing nuclear facilities in countries like Sweden can compete with all fossil fuels in the generation of electricity; and that claims that unconventional or renewable energy sources are economic at the present time are misleading, and might serve to accelerate the introduction of a plutonium-based energy economy. [source] Aluminium production options with a focus on the use of a hydrogen anode: a reviewASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2007Sankar Namboothiri Abstract The Hall,Héroult process for the production of aluminium uses a consumable carbon anode. Owing to the environmental effects of the consumable carbon anodes, the primary aluminium industry is under increasing pressure to improve on the Hall,Héroult process to make it more environmentally friendly. Inert anodes would provide a major technical revolution, as they may yield significant cost, energy and environmental benefits. However, no fully acceptable inert anode material has been developed to date. Other alternative technologies had been investigated and tested, but with little success so far. The use of a hydrogen anode for the production of aluminium is an interesting concept, as it will have the same reversible voltage as a carbon anode in a conventional Hall,Héroult cell, and it will considerably reduce greenhouse gas emissions. This paper reviews the various process options for aluminium electrowinning with a focus on the application of hydrogen anode in aluminium electrowinning. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Effects of butyric acid stress on anaerobic sludge for hydrogen production from kitchen wastesJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2010Mingxing Zhao Abstract BACKGROUND: Anaerobic digestion is an alternative technology to achieve the dual benefits of hydrogen production and waste stabilization from kitchen wastes. In this work, the butyric acid stress on anaerobic sludge was investigated in order to improve the tolerance of sludge against organic acids, and to enhance hydrogen accumulation. RESULTS: The tolerance of butyric acid in anaerobic sludge increased with the stress concentration, however, it decreased at concentrations greater than of 4.0 g L,1. The maximum hydrogen yield reached 63.72 mL g,1 VS at 4.0 g L,1 stress, representing an increase of 114% compared with the control group. The concentration of volatile solids (VS) of the sludge and SCOD increased steadily with time up to 20 h. At 4.0 g L,1 butyric acid stress, the maximum activity of ,-glucosidase, BAA-hydrolysing protease and dehydrogenase enzyme were 14912.1 µmol PNP g,1 TS h,1, 134.14 µmol NH4 -N g,1 TS h,1 and 7316.42 µg TF g,1 TS h,1, which were 2.78, 1.90 and 2.01 times that of the control, respectively. CONCLUSIONS: The feasibility of butyric acid stress on anaerobic sludge to increase hydrogen production from kitchen wastes was demonstrated. Remarkably, 4.0 g L,1 butyric acid stress was found to be favorable for improving the tolerance of butyric acid in sludge as well as hydrogen yield in the experiment. Copyright © 2010 Society of Chemical Industry [source] Projective techniques for the growth of compound semiconductor nanostructuresPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003T. Schallenberg Abstract We investigate the geometric deposition of compound semiconductors through shallow shadow masks as a means to obtain 3D nanostructures in situ. A high spatial resolution in the order of 10 nm and good material quality are achieved by epitaxy with directed molecular beams through stationary masks. Based on our study of growth dynamics new processes were tailored for the deposition of compound semiconductors. These expand the degrees of freedom of directional shadow growth. We would like to give an overview of this alternative technology, and present late results from experiments with an optimised molecular beam epitaxy (MBE) set-up. Projective techniques are demonstrated with sample structures. We discuss their respective potential and limitations. An outlook shows the perspective of further increase of the complexity of feasible structures by increasing the complexity of the masks (3D nanostructured). [source] Sustainable soil remediation by refrigerated condensation at sites with "high-concentration" recalcitrant compounds and NAPL: Two case studiesREMEDIATION, Issue 1 2008Lowell Kessel Remediation of recalcitrant compounds at sites with high concentrations of volatile organic compounds (VOCs) or nonaqueous-phase liquids (NAPLs) can present significant technical and financial (long-term) risk for stakeholders. Until recently, however, sustainability has not been included as a significant factor to be considered in the feasibility and risk evaluation for remediation technologies. The authors present a framework for which sustainability can be incorporated into the remediation selection criteria focusing specifically on off-gas treatment selection for soil vapor extraction (SVE) remediation technology. SVE is generally considered an old and standard approach to in situ remediation of soils at a contaminated site. The focus on off-gas treatment technology selection in this article allows for more in-depth analysis of the feasibility evaluation process and how sustainable practices might influence the process. SVE is more commonly employed for recovery of VOCs from soils than other technologies and generally employs granular activated carbon (GAC), catalytic, or thermal oxidation, or an emerging alternative technology known as cryogenic-compression and condensation combined with regenerative adsorption (C3,Technology). Of particular challenge to the off-gas treatment selection process is the potential variety of chemical constituents and concentrations changing over time. Guidance is available regarding selection of off-gas treatment technology (Air Force Center for Environmental Excellence, 1996; U.S. Environmental Protection Agency, 2006). However, there are common shortcomings of off-gas treatment technology guidance and applications; practitioners have rarely considered sustainability and environmental impact of off-gas treatment technology selection. This evaluation includes consideration of environmental sustainability in the selection of off-gas treatment technologies and a region-specific (Los Angeles, California) cost per pound and time of remediation comparisons between GAC, thermal oxidation, and C3,Technology. © 2008 Wiley Periodicals, Inc. [source] | |||||||||||||