نتایج جستجو برای: greenhouse
تعداد نتایج: 33140 فیلتر نتایج به سال:
In the coming years, humans will have choices to make about where we get the fuel that powers our lights for us to see at night, our stoves for our hot meals, our water heaters for our warm baths, and even our cars. These choices will affect the air we breathe: burning fuel often causes pollution, like the smog found in cities, and almost always leads to more greenhouse gases in the air. Smog a...
In this work, a statistical analysis on greenhouse simulations to estimate the efficiency of natural ventilation in a commercial twin-span greenhouse is presented. A numerical simulation approach was adopted using the theory of threedimensional computational fluid dynamics (CFD). With this approach, threedimensional patterns for temperature and airspeed inside the greenhouse were generated, usi...
Reports of disappearing glaciers, shrinking arctic ice, rising sea levels, stronger hurricanes, and unprecedented European heat waves combined with an inexorable buildup in atmospheric carbon dioxide levels is increasing pressure on governments to respond with new greenhouse gas initiatives. California and other states are providing policy leadership in the United States. Of particular interest...
Soil labile C and N fractions can change rapidly in response to management practices compared to non-labile fractions. High variability in soil properties in the field, however, results in nonresponse to management practices on these parameters. We evaluated the effects of residue placement (surface application [or simulated no-tillage] and incorporation into the soil [or simulated conventional...
OBJECTIVES Greenhouse operations are an important sector of the horticulture industry, also known as the Green Industry. The objectives of this study were (i) to investigate exposure levels to airborne culturable fungi, bacteria (total culturable bacteria and actinomycetes), endotoxin, and (1→3)-β-D-glucan in three Midwest greenhouses during summer and winter using multiple exposure assessment ...
For some years now, problems relating to gas emissions that affect climate and result from human activities have assumed a global dimension of large importance. The climate is, indeed, influenced by the concentrations of some pollutants in the atmosphere; these pollutants trap the long wave radiation emitted by the Earth and alter the energy balance, causing an accentuation of the natural green...
UNLABELLED BACKGROUND The therapeutic activities of Andrographis paniculata are attributed to four major active diterpenoids: andrographolide (AP1), 14-deoxy-11,12-didehydroandrographolide (AP3), neoandrographolide (AP4), and 14-deoxyandrographolide (AP6). This study aims to quantify the four active diterpenoids in various plant organs of A. paniculata at different growth stages in greenhous...
the purpose of present research was studying the educational need assessment of greenhouse holders growing ornamental plants and flowers about applying alternative energies. this research is application with descriptive- correlative method. statistical community was 499 subjects of greenhouse holders of ornamental plants and flowers in tehran province. by using simple random sampling method and...
Since there are major gaps in scientific knowledge about the greenhouse effect, policy makers are forced to rely on scientists’ judgments about the rate of climate change and its effects. It now appears that significant policy decisions will have to be made despite continuing uncertainty and disagreement among scientists. The best that policy makers can do is look for guidance in the best avail...
Model-based control techniques are commonly applied to control the greenhouse climate. As well-known, these techniques require accurate models for adequate results. Several first-principle models have been developed for the greenhouse climate control problem considering all the physical and physiological processes. However, these models are too complex to be used for control purposes. On the ot...
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