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31.
Fermentation of lignocellulosic biomass requires auxiliary materials, including nutrients, to ensure the proliferation of microorganisms. Nutrients are usually inexpensive, but their contribution to the cost is considerable because of the very low prices of fermentation products, such as bio-ethanol. Using substances present in native lignocellulosic biomass as nutrients for fermentation was proposed and demonstrated. Leaves and stalks of corn plants were used as biomass, and nutrients were recovered as a nutrient solution by soaking them in water before alkaline peroxide pretreatment. Pretreated biomass and the nutrient solution derived from the same lot were used for non-sterile simultaneous enzymatic saccharification and thermophilic l-lactic acid fermentation (SSF). Using the nutrient solution in the saccharification step did not impact sugar recovery, and instead improved sugar yields because of the presence of eluted sugars in the solution. The l-lactic acid yield of 0.33 g g?1 based on native biomass weight indicated that the nutrient solution functioned as a source of nutrients and sugars, especially as a source of essential phosphorus. Comparatively, autoclaved SSF yielded less or no l-lactic acid, indicating an apparent inhibitive effect derived from the nutrient solution on bacterial growth.  相似文献   
32.
Simultaneous measurements of gaseous species and fine-mode, particulate inorganic components were performed at the University of Seoul, Seoul in Korea. In the simultaneous measurements, a certain level of nitrous acid (HONO) was observed in the gas-phase, indicating possible heterogeneous HONO production on the surface of the ambient aerosols. On the other hand, high particulate nitrite (NO2?) concentrations of 1.41(±2.26) μg/m3 were also measured, which sometimes reached 18.54 μg/m3. In contrast, low HONO-to-NO2 ratios of 0.007(±0.006) were observed in Seoul. This indicates that a significant fraction of HONO is dissolved in atmospheric aerosols. Around the Seoul site, sufficient alkalinity may have been provided to the atmospheric aerosols from the excessive presence of NH3 in the gas-phase. Due to the alkaline particulate conditions (defined in this study as a particle pH >~3.29), the HONO molecules produced at the surface of the atmospheric aerosols appeared to have been converted into particulate nitrite, thereby preventing their further participation in the atmospheric O3/NOy/HOx photochemical cycles. It was estimated that a minimum average of 65% of HONO was captured by alkaline, anthropogenic, urban particles in the Seoul measurements.  相似文献   
33.
Size-resolved chemical compositions of non-refractory submicron aerosols were measured using a quadrupole Aerodyne aerosol mass spectrometer at a rural site near Guangzhou in the Pearl River Delta (PRD) of China in the summer of 2006. Two cases characterized as the outflows from the PRD urban region with plumes of high SO2 concentration were investigated. The evolution of sulfate size distributions was observed on a timescale of several hours. Namely mass concentrations of sulfate in the condensation mode (with vacuum aerodynamic diameters (Dva) < 300 nm) increased at a rate of about 0.17–0.37 ppbv h?1 during the daytime. This finding was consistent with the sulfuric acid production rates of about 0.17–0.3 ppbv h?1, as calculated from the observed gas-phase concentrations of OH (~3.3 × 106–1.7 × 107 cm?3) and SO2 (~3–21.2 ppbv). This implies that the growth of sulfate in the condensation mode was mainly due to gas-phase oxidation of SO2. The observed rapid increase was caused mainly by the concurrent high concentrations of OH and SO2 in the air mass. The evolution of the mass size distributions of m/z 44, a tracer for oxygenated organic aerosol (OOA), was very similar to that of sulfate. The mass loadings of m/z 44 were strongly correlated with those of sulfate (r2 = 0.99) in the condensation mode, indicating that OOA might also be formed by the gas-phase oxidation of volatile organic compound (VOC) precursors. It is likely that sulfate and OOA were internally mixed throughout the whole size range in the air mass.  相似文献   
34.
A highly sensitive cavity ring-down spectrometer (CRDS) was used to monitor the aerosol extinction coefficient at 532 nm. The performance of the spectrometer was evaluated using measurements of nearly monodisperse polystyrene particles with diameters between 150 and 500 nm. By comparing the observed results with those determined using Mie theory, the accuracy of the CRDS instrument was determined to be >97%, while the upper limit for the precision of the instrument was estimated to be 0.6–3.5% (typically 2%), depending on the particle number concentration, which was in the range of 30–2300 particles cm?3. Simultaneous measurements of the extinction (bext), scattering (bsca) and absorption (babs) coefficients of ambient aerosols were performed in central Tokyo from 14 August to 2 September 2007 using the CRDS instrument, two nephelometers and a particle/soot absorption photometer (PSAP), respectively. The value of bext measured using the CRDS instrument was compared with the sum of the bsca and babs values measured with a nephelometer and a PSAP, respectively. Good agreement between the bext and bsca + babs values was obtained except for data on days when high ozone mixing ratios (>130 ppbv) were observed. During the high-O3 days, the values for bsca + babs were ~7% larger than the value for bext, possibly because the value for babs measured by the PSAP was overestimated due to interference from coexisting non-absorbing aerosols such as secondary organic aerosols.  相似文献   
35.
36.
Coal mine reclamation projects are very expensive and require coordination of local and federal agencies to identify resources for the most economic way of reclaiming mined land. Location of resources for mine reclamation is a spatial problem. This article presents a methodology that allows the combination of spatial data on resources for the coal mine reclamation and uses GIS analysis to develop a priority list of potential mine reclamation sites within contiguous United States using the method of extrapolation. The extrapolation method in this study was based on the Bark Camp reclamation project. The mine reclamation project at Bark Camp, Pennsylvania, USA, provided an example of the beneficial use of fly ash and dredged material to reclaim 402,600 sq mi of a mine abandoned in the 1980s. Railroads provided transportation of dredged material and fly ash to the site. Therefore, four spatial elements contributed to the reclamation project at Bark Camp: dredged material, abandoned mines, fly ash sources, and railroads. Using spatial distribution of these data in the contiguous United States, it was possible to utilize GIS analysis to prioritize areas where reclamation projects similar to Bark Camp are feasible. GIS analysis identified unique occurrences of all four spatial elements used in the Bark Camp case for each 1 km of the United States territory within 20, 40, 60, 80, and 100 km radii from abandoned mines. The results showed the number of abandoned mines for each state and identified their locations. The federal or state governments can use these results in mine reclamation planning.  相似文献   
37.
The emission of waste in an economy, including landfill, is to a large extent determined by its patterns of technology, institutions, and lifestyle. A mathematical model (the waste input–output model) is presented that gives a simple analytical representation of this interdependence. The model was used to evaluate the effects of alternative waste disposal and recycling options on the levels of industrial production, landfill consumption, and the emission of carbon dioxide, and also to analyze the overall dependence on landfill of individual industries. It was found that a systematic combination of the options could be effective in reducing the overall landfill consumption and carbon dioxide emission. Received: November 4, 2000 / Accepted: August 2, 2001  相似文献   
38.
Predictors of employee aggression against coworkers, subordinates, and supervisors were studied in a sample of 136 men employed full‐time. Person behaviors (history of aggression, amount of alcohol consumed) predicted aggression against a coworker. In contrast, aggression against a supervisor was predicted by two perceived workplace factors (procedural justice, workplace surveillance). However, neither person behaviors nor perceived workplace factors predicted aggression against a subordinate. In addition, person behaviors and perceived workplace factors interacted to predict aggression. First, procedural justice interacted with amount of alcohol consumed in predicting both aggression against a coworker and aggression against a subordinate. Secondly, both job security and procedural justice interacted with history of aggression in predicting aggression against a subordinate. Finally, job security and amount of alcohol consumed interacted to predict aggression against a subordinate. Results suggest that both the understanding and prediction of employee aggression will be enhanced by taking into account the target of employee aggression, and by including both perceived workplace factors and person behaviors as predictor variables. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   
39.
Dimethyl sulphide (DMS) and carbon monoxide (CO) are climate-relevant trace gases that play key roles in the radiative budget of the Arctic atmosphere. Under global warming, Arctic sea ice retreats at an unprecedented rate, altering light penetration and biological communities, and potentially affect DMS and CO cycling in the Arctic Ocean. This could have socio-economic implications in and beyond the Arctic region. However, little is known about CO production pathways and emissions in this region and the future development of DMS and CO cycling. Here we summarize the current understanding and assess potential future changes of DMS and CO cycling in relation to changes in sea ice coverage, light penetration, bacterial and microalgal communities, pH and physical properties. We suggest that production of DMS and CO might increase with ice melting, increasing light availability and shifting phytoplankton community. Among others, policy measures should facilitate large-scale process studies, coordinated long term observations and modelling efforts to improve our current understanding of the cycling and emissions of DMS and CO in the Arctic Ocean and of global consequences.  相似文献   
40.
Human activities are changing the Arctic environment at an unprecedented rate resulting in rapid warming, freshening, sea ice retreat and ocean acidification of the Arctic Ocean. Trace gases such as nitrous oxide (N2O) and methane (CH4) play important roles in both the atmospheric reactivity and radiative budget of the Arctic and thus have a high potential to influence the region’s climate. However, little is known about how these rapid physical and chemical changes will impact the emissions of major climate-relevant trace gases from the Arctic Ocean. The combined consequences of these stressors present a complex combination of environmental changes which might impact on trace gas production and their subsequent release to the Arctic atmosphere. Here we present our current understanding of nitrous oxide and methane cycling in the Arctic Ocean and its relevance for regional and global atmosphere and climate and offer our thoughts on how this might change over coming decades.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01633-8.  相似文献   
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