19,354 research outputs found

    Comparative energetic assessment of methanol production from CO₂: chemical versus electrochemical process

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    Emerging emission-to-liquid (eTL) technologies that produce liquid fuels from CO₂ are a possible solution for both the global issues of greenhouse gas emissions and fossil fuel depletion. Among those technologies, CO₂ hydrogenation and high-temperature CO₂ electrolysis are two promising options suitable for large-scale applications. In this study, two CO₂ -to-methanol conversion processes, i.e., production of methanol by CO₂ hydrogenation and production of methanol based on high-temperature CO₂ electrolysis, are simulated using Aspen HYSYS. With Aspen Energy Analyzer, heat exchanger networks are optimized and minimal energy requirements are determined for the two different processes. The two processes are compared in terms of energy requirement and climate impact. It is found that the methanol production based on CO₂ electrolysis has an energy efficiency of 41%, almost double that of the CO₂ hydrogenation process provided that the required hydrogen is sourced from water electrolysis. The hydrogenation process produces more CO₂ when fossil fuel energy sources are used, but can result in more negative CO₂ emissions with renewable energies. The study reveals that both of the eTL processes can outperform the conventional fossil-fuel-based methanol production process in climate impacts as long as the renewable energy sources are implemented

    Electrodialytic processes in solid matrices. New insights into batteries recycling. A review.

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    Electrodialytic Remediation has been widely applied to the recovery of different contaminants from numerous solid matrices solving emerging issues of environmental concern. Results and conclusions reported in studies about real contaminated matrices are summarizes in this work. The influence of the pH value on the treatment effectiveness has been widely proved highlighting the phenomenon “water splitting” in the membrane surface. This dissociation of water molecules is related to the “limiting current” which is desirable to be exceed at the Anion Exchange Membrane in order to produce the entering of protons toward solid matrix. Other important parameters for the optimization of the technique, such as the current density and the liquid to solid ratio, are also discussed through the revision of studies using real solid matrices. This work also focusses on the pioneer proposal of electrokinetic technologies for the recycling of lithium ion batteries considering the relevance of waste properties in the design and optimization of the technique. From a thorough literature revision, it could be concluded that further experimental results are needed to allow an optimal application of the technique to the rising problem of residues from batteries. The main aim of this work is to take the first steps in the recovery of valuable metals from spent batteries, such as Li and Co, incorporating principles of green chemistry.The authors acknowledge the financial support from the “Plan Propio de Investigación de la Universidad de Málaga with Project numbers: PPIT.UMA.B1.2017/20 and PPIT.UMA.B5.2018/17 and the European project THROUGH H2020-MSCA-RISE- 2017-778045. The first author also acknowledge the postdoctoral contract obtained from University of Malaga

    Research reports: 1990 NASA/ASEE Summer Faculty Fellowship Program

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    Reports on the research projects performed under the NASA/ASEE Summer Faculty Fellowship Program are presented. The program was conducted by The University of Alabama and MSFC during the period from June 4, 1990 through August 10, 1990. Some of the topics covered include: (1) Space Shuttles; (2) Space Station Freedom; (3) information systems; (4) materials and processes; (4) Space Shuttle main engine; (5) aerospace sciences; (6) mathematical models; (7) mission operations; (8) systems analysis and integration; (9) systems control; (10) structures and dynamics; (11) aerospace safety; and (12) remote sensin

    Microgravity: A Teacher's Guide With Activities in Science, Mathematics, and Technology

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    The purpose of this curriculum supplement guide is to define and explain microgravity and show how microgravity can help us learn about the phenomena of our world. The front section of the guide is designed to provide teachers of science, mathematics, and technology at many levels with a foundation in microgravity science and applications. It begins with background information for the teacher on what microgravity is and how it is created. This is followed with information on the domains of microgravity science research; biotechnology, combustion science, fluid physics, fundamental physics, materials science, and microgravity research geared toward exploration. The background section concludes with a history of microgravity research and the expectations microgravity scientists have for research on the International Space Station. Finally, the guide concludes with a suggested reading list, NASA educational resources including electronic resources, and an evaluation questionnaire

    Ono: an open platform for social robotics

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    In recent times, the focal point of research in robotics has shifted from industrial ro- bots toward robots that interact with humans in an intuitive and safe manner. This evolution has resulted in the subfield of social robotics, which pertains to robots that function in a human environment and that can communicate with humans in an int- uitive way, e.g. with facial expressions. Social robots have the potential to impact many different aspects of our lives, but one particularly promising application is the use of robots in therapy, such as the treatment of children with autism. Unfortunately, many of the existing social robots are neither suited for practical use in therapy nor for large scale studies, mainly because they are expensive, one-of-a-kind robots that are hard to modify to suit a specific need. We created Ono, a social robotics platform, to tackle these issues. Ono is composed entirely from off-the-shelf components and cheap materials, and can be built at a local FabLab at the fraction of the cost of other robots. Ono is also entirely open source and the modular design further encourages modification and reuse of parts of the platform

    Pretreatment Processes of Biomass for Biorefineries: Current Status and Prospects

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    Producción CientíficaThis article seeks to be a handy document for the academy and the industry to get quickly up to speed on the current status and prospects of biomass pretreatment for biorefineries. It is divided into two biomass sources: vegetal and animal. Vegetal biomass is the material produced by plants on land or in water (algae), consuming sunlight, CO2, water, and soil nutrients. This includes residues or main products from, for example, intensive grass crops, forestry, and industrial and agricultural activities. Animal biomass is the residual biomass generated from the production of food from animals (e.g., manure and whey). This review does not mean to include every technology in the area, but it does evaluate physical pretreatments, microwave-assisted extraction, and water treatments for vegetal biomass. A general review is given for animal biomass based in physical, chemical, and biological pretreatments

    Pyrolysis of Wastewater Biosolids Significantly Reduces Estrogenicity

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    Most wastewater treatment processes are not specifically designed to remove micropollutants. Many micropollutants are hydrophobic so they remain in the biosolids and are discharged to the environment through land-application of biosolids. Micropollutants encompass a broad range of organic chemicals, including estrogenic compounds (natural and synthetic) that reside in the environment, a.k.a. environmental estrogens. Public concern over land application of biosolids stemming from the occurrence of micropollutants hampers the value of biosolids which are important to wastewater treatment plants as a valuable by-product. This research evaluated pyrolysis, the partial decomposition of organic material in an oxygen-deprived system under high temperatures, as a biosolids treatment process that could remove estrogenic compounds from solids while producing a less hormonally active biochar for soil amendment. The estrogenicity, measured in estradiol equivalents (EEQ) by the yeast estrogen screen (YES) assay, of pyrolyzed biosolids was compared to primary and anaerobically digested biosolids. The estrogenic responses from primary solids and anaerobically digested solids were not statistically significantly different, but pyrolysis of anaerobically digested solids resulted in a significant reduction in EEQ; increasing pyrolysis temperature from 100 °C to 500 °C increased the removal of EEQ with greater than 95% removal occurring at or above 400 °C. This research demonstrates that biosolids treatment with pyrolysis would substantially decrease (removal \u3e 95%) the estrogens associated with this biosolids product. Thus, pyrolysis of biosolids can be used to produce a valuable soil amendment product, biochar, that minimizes discharge of estrogens to the environment

    The impact and fate of aqueous sodium nitrate on hydrocarbon flames

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    This study examined the impact and fate of sodium (fed as an aqueous nitrate solution) in fuel-rich methane/air and methane/methyl chloride/air flames as a function of equivalence ratios that experienced diffusion of air from the surroundings. The flames were stabilized on a slotted, uncooled burner. The data set was divided into profiles of relative sodium atom concentrations, temperatures, and selected stable species concentrations. The flames were simulated using a modified version of the Sandia FORTRAN program for modeling steady laminar one-dimensional premixed flames complete with detailed mechanisms. The results showed that maximum sodium atom concentration in the flame is decreased by an increase in equivalence ratio as well as an increase in chlorine loading. In addition, the location of maximum sodium atom concentration is shifted to a higher height above burner as the equivalence ratio is increased
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