[{"id":397,"title":"Heat-integrated household ","sha":"bab1ea358d6d396d0dffc91fe4edd9fb","user_id":null,"state":"published","body":"In a typical household there are appliances for heating and other appliances for cooling. The former, including geysers, stoves, ovens and space heaters, typically use a heating element - an inefficient approach from an energy usage standpoint. The latter group of appliances is tasked with cooling and includes freezers, refrigerators and air-conditioners. These make use of heat pumps to generate a cold and a hot stream, discharging the latter as waste heat.\r\n\r\nSimple heat integration of hot and cold appliances would result in significant savings in household energy consumption. A single heat pump replacing a household geyser would draw less electricity than a heating element with the same heating duty, and would still supply cold streams sufficient for a refrigerator, a freezer, and potentially an air-conditioner, when required. Thus, all of these appliances could collectively be operated while drawing less electricity than a typical geyser, considerably reducing household energy consumption.\r\n\r\n","created_at":"2017-07-31T16:13:10.853Z","updated_at":"2018-02-27T20:16:02.697Z","zenodo_id":838876,"doi":"https://doi.org/10.5281/zenodo.838876","subject":null,"tags":["energy","climate change"],"vote_count":1,"view_count":1,"score":1.1,"deleted":false,"muted":false,"tweeted":false,"attachment_file_name":null,"attachment_content_type":null,"attachment_file_size":null,"attachment_updated_at":null},{"id":399,"title":"Better modeling of membrane permeation through multi-membrane models","sha":"84ef3dbb77245cae8486c9a5cfd7d93b","user_id":null,"state":"published","body":"Membrane permeation is frequently modeled using a vector of relative permeabilities for each component that is permeated. However, no membrane material will have truly uniform permeability; instead, any particular membrane material exhibits variance in physical properties and permeability across its surface. In a very real sense, any single permeating surface can be thought of as a distribution of slightly different membranes as opposed to truly being a single membrane.  \r\n\r\nMulti-membrane permeation parameters can be fit to existing single-membrane characterization data to produce a more accurate permeation model for any particular membrane material.","created_at":"2017-08-07T14:49:54.667Z","updated_at":"2017-08-08T06:00:32.932Z","zenodo_id":839878,"doi":"https://doi.org/10.5281/zenodo.839878","subject":null,"tags":["separation","membranes"],"vote_count":0,"view_count":1,"score":0.1,"deleted":false,"muted":false,"tweeted":false,"attachment_file_name":null,"attachment_content_type":null,"attachment_file_size":null,"attachment_updated_at":null},{"id":411,"title":"Oxygen enrichment to enhance training effectiveness and physiological adaptation","sha":"5633b0be0c9102d57dc2efe6e947f0de","user_id":null,"state":"published","body":"For decades, sportspersons have lived by the adage “live high, train low,” an approach that has been repeatedly borne out by research. High altitude adaptations improve performance, while the availability of more oxygen at low altitude permits more intense and more effective training. It has not yet been investigated whether these benefits continue to increase when oxygen partial pressure is increased beyond that which is found at sea level.\r\nIt can be hypothesized that slightly enriched oxygen content in a training context will result in increased intensity and physiological adaptation. This could be achieved straightforwardly by using a membrane permeator somewhat selective to oxygen, since only a small degree of separation is required to create an oxygen-enriched training environment. \r\nSuch a setup would be of interest to high-performance centres for professional athletes as well as facilities for physical rehabilitation and potentially, commercial gyms – particularly those at high altitude.\r\n","created_at":"2017-10-10T09:31:32.892Z","updated_at":"2017-10-17T06:00:39.380Z","zenodo_id":1013924,"doi":"https://doi.org/10.5281/zenodo.1013924","subject":null,"tags":["sports science","exercise physiology"],"vote_count":0,"view_count":1,"score":0.1,"deleted":false,"muted":false,"tweeted":true,"attachment_file_name":null,"attachment_content_type":null,"attachment_file_size":null,"attachment_updated_at":null},{"id":415,"title":"Operational and lifecycle advantages of hybridized iron ore reduction and biomass gasification","sha":"d579f9e2301065453dde71408f1be61c","user_id":null,"state":"published","body":"Recent research has demonstrated that biomass can be used as a reducing agent for iron ore but also that iron ore reduction can be coupled with biomass gasification, co-producing reduced iron and synthesis gas which can itself be converted to liquid fuels through the Fischer Tropsch process. \r\nEconomic analysis has revealed that iron is the preferred product from a financial standpoint and that such processes will tend to focus on producing iron, with a trade-off in terms of synthesis gas production. However, critical operational considerations have yet to be considered. An iron smelter's design capacity is constant but the productivity of an iron mine is initially far below that capacity, taking years to reach full capacity, fluctuating over the course of its lifespan and then diminishing to nothing when the iron deposit is depleted. Co-production permits this operational deficit to be met with increased gasification and allows for conversion to dedicated gasification after the mine's lifespan. \r\nBesides offering a carbon-neutral alternative to coal for iron smelting, this technology therefore offers a means of increasing smelter productivity and a pathway toward a renewable fuels industry, with the capital expenses covered by the iron smelting phase of operation.","created_at":"2017-10-18T08:54:54.610Z","updated_at":"2017-10-19T06:00:33.311Z","zenodo_id":1018918,"doi":"https://doi.org/10.5281/zenodo.1018918","subject":null,"tags":["renewability","carbon emissions","engineering"],"vote_count":0,"view_count":1,"score":0.1,"deleted":false,"muted":false,"tweeted":true,"attachment_file_name":null,"attachment_content_type":null,"attachment_file_size":null,"attachment_updated_at":null},{"id":436,"title":"Use of waste plastic as a reducing agent for iron ore","sha":"a68934a13a3acecaf3a25b551b5c7332","user_id":null,"state":"published","body":"China's recent announcement that they will cease to accept large quantities of waste plastic has brought a growing crisis into sharp focus; global capacity for waste plastic handling is being rapidly outstripped by production. The clear solution is to find ways of profitably utilizing waste plastic, preferably involving total chemical conversion to non-persistent substances.\r\nOne possibility that has been previously neglected is that of using plastic instead of coal as a reducing agent for iron ore. The first criterion for a reducing agent is the chemical capacity to take up the excess oxygen atoms contained in hematite and magnetite. Polyethylene polymer has an effective chemical formula of (C2H4)n, and both Carbon and Hydrogen can be bonded to oxygen to form a range of stable compounds. The other criterion for a viable reducing agent is possessing sufficient chemical energy to drive the endothermic reduction of iron. Polyethylene has an enthalpy of formation of -(94.26n)kJ/mol and a Gibbs free energy of formation of -(36.44n)kJ/mol, giving it sufficient energy density for this purpose. In principle, therefore, it is perfectly viable to use waste plastic instead of coal for the reduction of iron ore.","created_at":"2018-01-18T09:36:12.903Z","updated_at":"2018-01-30T06:01:09.762Z","zenodo_id":1162364,"doi":"https://doi.org/10.5281/zenodo.1162364","subject":null,"tags":["emissions","plastic","recycling","iron"],"vote_count":0,"view_count":1,"score":0.1,"deleted":false,"muted":false,"tweeted":true,"attachment_file_name":null,"attachment_content_type":null,"attachment_file_size":null,"attachment_updated_at":null},{"id":448,"title":"Effects of temperature on alcohol tolerance of microbes","sha":"aa69dd7fcd1632e75f773f87ae384ca5","user_id":null,"state":"published","body":"It has been established that dissolution of membrane lipids plays a role in the toxicity of ethanol and butanol to micro-organisms; a matter of particular importance for the production of bio-alcohol fuels using fermentation by microbial activity. However, solubility is a phenomenon heavily governed by temperature.\r\nIt follows that microbial tolerance of these substances will tend to vary with temperature, a phenomenon that has not been studied outside of a narrow range of temperatures in which fermentation is typically conducted, largely because fermentation rate is optimized within that range. However, the main costs involved in bio-alcohol production are feedstock material followed by separation costs. The former of these cost factors is determined by fermentation yield relative to mass and the latter is determined by alcohol product purity which is in turn governed by alcohol tolerance. Fermentation rate only affects reactor sizing, a moderate factor in capital cost with little bearing on operating cost. Hence, compromising fermentation rate in pursuit of alcohol tolerance by exploring unconventional temperature ranges could potentially offer improvements in overall economic performance of bio-alcohol production. ","created_at":"2018-03-22T12:09:37.645Z","updated_at":"2018-05-09T07:40:31.832Z","zenodo_id":1208713,"doi":"https://doi.org/10.5281/zenodo.1208713","subject":null,"tags":["biology","biofuels","fuel"],"vote_count":1,"view_count":1,"score":1.1,"deleted":false,"muted":false,"tweeted":true,"attachment_file_name":null,"attachment_content_type":null,"attachment_file_size":null,"attachment_updated_at":null},{"id":451,"title":"Microbial butanol tolerance: mediated by toxicity or by phase equilibrium?","sha":"ea407c9f242be9b2102d68134bc245bb","user_id":null,"state":"published","body":"It is conventionally assumed that the achievable concentration of a bio-alcohol molecule by fermentation is limited by the toxicity of that molecule to the micro-organisms producing it. In the case of ethanol, for example, extremely high titers have been achieved by developing resistant strains of micro-organism. Butanol, conversely, has proven remarkably stubborn to this same sort of progression. Despite widespread efforts, concentration above 2% have not been achieved. \r\n2% also happens to be the limit of solubility of butanol in water. It seems intuitive that intra-cellular phase separation would result in highly toxic localized concentrations of butanol, and generally disrupt material transport through cell membranes. This would suggest that butanol titers are fundamentally limited by phase equilibrium and that conventional research to improve butanol tolerance will prove fruitless. \r\nThis hypothesis could be tested experimentally in one of two ways. Firstly, ethanol-producing organisms could be cultivated in a 2% butanol solution. If toxicity is severe then they would be highly inhibited in this environment but if phase equilibrium is the limit then they will cope well. Alternatively, higher temperatures improve solubility. Hence, if butanol tolerance increases with temperature it can be inferred that solubility is limiting.","created_at":"2018-04-05T11:33:47.204Z","updated_at":"2020-07-17T13:07:43.841Z","zenodo_id":1219005,"doi":"https://doi.org/10.5281/zenodo.1219005","subject":null,"tags":["butanol","bio-fuels","biology"],"vote_count":1,"view_count":1,"score":1.1,"deleted":false,"muted":false,"tweeted":true,"attachment_file_name":null,"attachment_content_type":null,"attachment_file_size":null,"attachment_updated_at":null},{"id":671,"title":"Fluidized bed for coffee brewing","sha":"a833e4975bff2455d4d3a9e466b87618","user_id":null,"state":"published","body":"Experimental and theoretical studies of the coffee brewing process have shown that most coffee preparation methods are affected by uneven particle distribution and uneven exposure of coffee grounds to hot water. This results in over-extraction from some percentage of the coffee granules and under-extraction from others, affecting both flavour and extraction efficiency.\r\n\r\nPrior research has focused on adjusting parameters such as coarseness of grind, temperature and pressure of water, and duration of exposure to address these issues, but elementary chemical reactor design offers a more comprehensive solution: the fluidized bed, a type of chemical reactor where upward fluid flow through a particle bed generates enough of a pressure difference to suspend those particles, permitting them to move freely between one another. \r\n\r\nAll conventional coffee brewing methods are essentially packed-bed type extractors, and it is well-known in the chemical industry that fluidized beds offer superior fluid flow dispersion and homogeneity of particle distribution, hence providing more complete and more uniform contact solid-fluid contact. It follows that fluidized bed extraction methods would address the shortfalls of coffee brewing methods, resulting in more complete and more consistent extraction, improving flavour and strength while reducing the quantity of coffee grounds that must be used.\r\n","created_at":"2020-01-24T06:25:15.206Z","updated_at":"2020-04-14T21:33:46.332Z","zenodo_id":3660064,"doi":"https://doi.org/10.5281/zenodo.3660064","subject":null,"tags":["coffee","brewing","engineering"],"vote_count":2,"view_count":1,"score":2.1,"deleted":false,"muted":false,"tweeted":true,"attachment_file_name":null,"attachment_content_type":null,"attachment_file_size":null,"attachment_updated_at":null},{"id":711,"title":"The role of mineral depletion on insect depopulation","sha":"8e224d20d4fadb46bb0ca158956831d6","user_id":null,"state":"published","body":"It has been established that the mineral content, particularly of trace minerals, in modern food crops is considerably lower than in their natural forms, a phenomenon that arises as a result of a number of causes. Intense fertilization methods, selective breeding of crop species, topsoil erosion and even plant morphology responses to elevated atmospheric carbon dioxide all contribute to radically depleted mineral content in cultivated crops. Wild plants can be expected to exhibit the same phenomenon, albeit to a lesser extent. This depletion could be expected to have significant nutritional implications for terrestrial animals. This effect would be more pronounced for insects than for feral grazing mammals, as the former have greater mobility to access and consume cultivated crops, which have the lowest mineral contents. \r\n\r\nIt has also been observed that insect populations have plummeted in the last 50 years, with no consensus as to the contributing causes and their respective severity. The role of nutritional deficiencies arising from mineral depletion has yet to be investigated, and could be a significant contributor to insect de-population.","created_at":"2020-02-28T08:58:40.575Z","updated_at":"2020-03-14T06:00:49.558Z","zenodo_id":3709099,"doi":"https://doi.org/10.5281/zenodo.3709099","subject":null,"tags":["insects","bees","extinction","nutrition"],"vote_count":0,"view_count":1,"score":0.1,"deleted":false,"muted":false,"tweeted":false,"attachment_file_name":null,"attachment_content_type":null,"attachment_file_size":null,"attachment_updated_at":null},{"id":713,"title":"Tuesday/Thursday shutdowns as a reduced economic impact alternative for epidemic control  ","sha":"4afa44bd515b07f6be6014e1c1102d1a","user_id":null,"state":"published","body":"Total isolation and quarantine are being deployed in citiesaffected by the COVID-19 infection. These measures, while effective, have devastating socio-economic consequences. An alternative method which could achieve a major reduction in the infection's basic reproduction rate but with less economic impact would be to impose shutdowns on Tuesdays and Thursdays. If infections were solely through direct contact, this would simply reduce workweek potentially infectious contacts (PICs) by 40% - however, the virus is believed to survive outside the body for 36 hours or longer, and hence PICs arise in a secondary fashion, albeit presumably at a reduced rate. Assuming an exponential decline in PICs over time, these second-day PICs will be roughly half as frequent as day-one contacts and hence, bundling variables into an arbitrary scaling factor x and assigning a value of 2x to the number of direct contacts occurring in one day, then a typical workweek would present the following distribution of PICs: 2x, 3x, 3x, 3x, 3x. A workweek with closures on Tuesdays and Thursdays would instead present a distribution of 2x, 0, 2x, 0, 2x; just 43% of the typical workweek. This is potentially sufficient to lower the reproduction rate below 1, thereby containing the epidemic. ","created_at":"2020-03-13T10:34:59.910Z","updated_at":"2020-06-23T12:07:13.943Z","zenodo_id":3709095,"doi":"https://doi.org/10.5281/zenodo.3709095","subject":null,"tags":["epidemiology"],"vote_count":3,"view_count":1,"score":3.1,"deleted":false,"muted":false,"tweeted":true,"attachment_file_name":null,"attachment_content_type":null,"attachment_file_size":null,"attachment_updated_at":null}]