In this study, in 2011 for the duration of two months, the dispersion of a major air pollutant, sulfurdioxidefromgas flares of an oil field, in Iran, was investigated. Due to the complexity of meteorological parameters in modeling area, California Puff (CALPUFF) model was used in this study. CALPUFF is a more advanced model than AERMOD which considers the effects of meteorological parameters in coastal areas, which was applied with meteorological and geophysical parameters produced by the Weather Research and Forecasting (WRF) model for the selected days of modeling period to investigate the impact of these parameters on modeling results. Since there is no option in the model for flares, flare parameters including emission rate and effective height and diameter were calculated based on EPA method to simulate better the real condition of flaring. Simulation results revealed that CALPUFF model could adequately express the effect of meteorological condition on results of modeling in each hour of the simulation period. The results of the simulation showed that low-height flares have the most impact on the ground level concentration of air pollutant on the island. The effects of elevated flares were at a far distance from flaring activity and mostly occurred outside of the island. CALPUFF model showed excellent compatibility with meteorological data produced by WRF and could properly account for the effect of meteorological and terrain parameters on dispersion modeling.
emission, namely: absorption, selective catalytic reduc- tion and non-sélective catalytic reduction . For methane reduction, the polluted gasstream is preheated to about 400˚C and then blended with the appropriate proportion of methane before passage over platinum or palladium catalytic surface for reduction . Selective catalytic abatement uses a catalyst and ammonia fuel to reduce NO x in preference to combustion with the much
To address this goal, several protocols have been proposed by governmental agencies regarding the safety of laboratory hoods [ 7- 9]. U.S. ANSI/ASHRAE 110- 1995 hood performance test is a widely believed test modified over the years by the American Society of Heating, Refrigeration and Air-conditioning Engineers (ASHRAE). In this protocol sulfur hexafluoride is recommended as a tracer gas to be applied for quantitative performance test of hoods [ 10, 11]. It is a suitable choice for this protocol because of its non- toxic, non-flammable properties as well as its likely of being detected at ppb levels using infrared absorption. Meanwhile, SF6 is a strong greenhouse gas while 23900 times more harmful than carbon dioxide. Typically 2 pounds of SF6 is applied in each test which is finally released to the atmosphere. The annual evaluation of all hoods may lead to a large scale releasing of SF6 to the environment [ 12]. High price of SF6 and its detector is another issue to be concerned. In the recent years the use of N 2 O as a substitute for SF6 based on
Natural gas is an odorless and colorless flammable fuel. There are many reports that gas leakage in household have caused irreparable fire damage; therefore, to control these incidents, odorization of gas is necessary. Natural gas odorization means addition of an odorant to gas to ensure characteristic odor of natural gas so that the odor becomes distinctive and unpleasant to the consumer. This way, the presence of gas in air in concentrations below the lower explosive limit (LEL) is readily detectable. After addition of any odorant to the gas, physical and chemical properties (except the smell) of natural gas should not change. Generally speaking, in the process of natural gas delivering for both public and industrial uses, odorization provides safety for those who use it. Historically, first gas odorization was carried out in Germany in 1880’s by Von Quaglio who used ethyl
The basic concept of the SVM denoising method is to construct a good model structure. Constructed model is able to predict unknown data and remove noise. Simple models cannot accurately predict unknown data, and overly complex models contain interference signals. The width of the gaussian radical kernel function is determined by the parameter r. According to adjust the parameter r, the complexity of the model is controlled by using the SVM. The model can accurately describe characterizes of unknown data, and removes noise information.
of Fairbanks (64.84 ◦ N, 147.72 ◦ W) along Route 3 (red line), OMI pixel boundaries for the 22:28 UTC Aura overpass (vertical blue lines; pixel numbers referred to in Table 1 are shown at top), extrap- olated FLYSPEC SO 2 columns averaged (unweighted) over corre- sponding OMI pixels (horizontal purple lines) and interpolated OMI SO 2 columns in the same pixels (horizontal green lines). The ab- scissa shows FLYSPEC time; time relative to the Aura overpass is indicated in parentheses. (a) Southbound traverse from Fair- banks; (b) northbound traverse towards Fairbanks. The absence of a peak in (b) is due to northward drift of the volcanic cloud during measurement.
Three proposed mechanisms exist for the source of ex- cess degassing: pre-eruptive bubbles in erupted magma, degassing of a convecting magma column, and a perme- able gas ﬂow model (Shinohara, 2008). For Plinian erup- tions, pre-eruptive gas bubbles in a magma chamber are the strongest candidate (Wallace, 2001; Scaillet et al., 2003). For effusive eruptions, all three mechanisms can cause ex- cess degassing, but the likelihood of pre-eruptive bubbles is especially strong for those that immediately follow an explosive eruption (Shinohara, 2008). Regarding the 2011 Shinmoedake eruption, if one assumes that the contribution of pre-eruptive bubbles is the source of excess degassing for the lava accumulation stages, then the relative amount of pre-eruptive bubbles in the magma chamber was probably low compared to the eruptions of Mt. St. Helens (Bluth et al., 1993; Gerlach and McGee, 1994) and Redout (Gerlach et al., 1994) volcanoes, which had similar explosive erup- tive sequences followed by effusive eruptions, with a high degree of excess degassing (greater than 8) for eruptions of both types (Shinohara, 2008).
ety of 3-hourly surface parameters and 6-hourly upper-air parameters that cover the troposphere and stratosphere are included in the data product. Here, the ERA-Interim stan- dard data on a 1 ◦ × 1 ◦ longitude–latitude grid are applied. The altitude coverage ranges from the surface to 0.1 hPa with 60 model levels. The vertical resolution in the upper troposphere and lower stratosphere (UT/LS) region varies between 700 and 1200 m. The 6-hourly temporal resolu- tion corresponds to data assimilation cycles at 00:00, 06:00, 12:00, and 18:00 UTC. A discussion of the analysis incre- ments of the ERA-Interim data, being a figure of merit for the data quality, can be found in Dee et al. (2011). Includ- ing a case study for the Nabro eruption, Hoffmann et al. (2016) showed that ERA-Interim data provided good perfor- mance in the Lagrangian transport simulations of volcanic SO 2 with MPTRAC in comparison with three other meteo-
The research area, Ahvaz, capital of Khuzestan Province, is the biggest city of south-western Iran, located around 31° 19' N and 48º 40' E, with an altitude of about 20 m above the mean sea level. With an annual precipitation of about 230 mm, the city has arid climate, its residential population equal to 1,112,021 in 2011. Ahvaz is consistently one of the hottest cities on the planet during summer, its summer temperature sometimes exceeding 50°C, while in winter the minimum temperature can be around +5°C (Guardian, 2016). Built on the banks of the Karun River, it is situated in the middle of Khuzestan Province. There are lots of cars travelling within the city as well as many factories and industrial hubs that generate lots of air pollutants like sulfurdioxide. As a result, Ahvaz is one of the most polluted cities in Iran which needs an ambient air quality analysis to conduct.
The most damaging long-term resource impact that can occur after wildfire is soil erosion. Erosion robs land of its soil and its ability to grow vigorous trees. A healthy forest functions to keep soil in place on the land. The forest canopy intercepts raindrops and reduces their impact on the soil. Rain which makes it through the canopy is intercepted by the litter layer which covers the forest floor. Together, the canopy and litter layer protect the soil by keeping the rain from detaching soil particles. Without this protection, detached soil particles can wash down denuded slopes, entering stream channels and reducing water quality and altering or degrading aquatic habitat.
with the formation of magnesium chloride solid by heating the solution. “Dow Chemical” is well known for recovering the magnesium from seawater and detail of its process as following (Wulandari et al., 2010). Lime was added to seawater to precipitate the magnesium from seawater by the formation of magnesium hydroxide and extracted the magnesium by injecting the hydrochloric acid. Next they precipitated the magnesium chloride solid to concentrate the acid solution and made magnesium metal through the electrolysis the magnesium chloride solid. The used hydrochloric acid was recovered for reuse. Through this method, Dow Chemical’s Texas plant produced 90000~100000 tons of magnesium per year from 50 million gallons of seawater per day (Mutaz & Wagialia, 1990). Meanwhile domestic company, “Posco chemtech”, exports magnesia (magnesium oxide) which was made by seawater and lime (Son et al., 2008).
The Wider Caribbean Region (WCR) includes a number of developing coun- tries for which agriculture, oil and gas exploration in conjunction with processing, provide valuable sources of income. As the WCR is one of the most tourism-dependent regions of the world, factors that affect environmental health and sustainability will have inevitable impacts to the economies and quality of life in many already-needy countries. Approximately 100 oil refineries are lo- cated within the WCR, with one of largest and oldest refineries, Isla Refineriá, being located in Willemstad, Curaçao . Communities downwind of Isla Refi- neriá and the major thoroughfare (Schottegatweg Ring) circling the refinery and the bay have self reported from questionnaires higher than average frequencies of headaches, nausea, chronic lung ailments, asthma and cancer . These self-reported questionnaire results have not been validated. A legacy of human health and environmental issues is the basis of a historical debate and conflict between the public and the local government of Curaçao. However, to our knowledge there has never been an exposure assessment conducted to evaluate ambient atmospheric levels of refinery emissions and their associated public health risks in Curaçao. Sanhueza et al.  determined that all areas downwind (≥5 km) of the Isla Refineriá in Curaçao were subject to sulfate contamination exceeding levels which have been previously associated with morbidity (≥8 - 12 µg/m 3 ). In addition, the 2007 yearly average SO
ioral responses can be found and planted to mitigate air pollu- tion. In addition, more parameters of C. camphora can be tested in order to further understand the adaptation of it under sulfurdioxide. This species remains poorly understood because most of the data did not change significantly or show obvious trends in this experiment. Therefore, future experiments must be con- ducted to investigate the effects on plants of other air pollutants, individually and in combination, to permit the selection of the optimal species for severely polluted regions. To fully under- stand how plants change under pollution stress, more parame- ters should be evaluated, including stomatal density, chloro- phyll fluorescence, and carbon fixation efficiency. To identify more air pollution tolerant plants, other common subtropical species, which were also mentioned in Wen et al. (2003), like Ficus microcarpa, Camellia japonica L., and Tutcheria spect- abilis (Benth.) Dunn, can also be tested.
achieving higher Berkowitz statistics out of 8 cases (3–5 week horizons) or 11 of 14 cases (all 7 horizons), under the assumption that the data were drawn from identically distributed, but cross-horizon correlated data. Paired sets (A and B) of uniformly distributed data were generated having the same correlation structure as the actual inverse probability transforms and with series lengths also matching the data. However, the paired data sets were constructed to have otherwise identical distributions. Pairs of Berkowitz statistics were then computed for each pair of constructed series. The process was repeated 10,000 times and the frequency of Berkowitz(A) > Berkowitz(B) in 8 of 8 cases (6.5% of simulations) and 11 of 14 cases (6.3% of simulations) was noted.
tion are broadly divided into the following two specifica- tions: (1) high hydrogen (tritium) concentration and low flow rate during plasma operation and (2) low hydrogen (tritium) concentration and high flow rate during the vac- uum vessel maintenance period and during roughing pump operation. The former demands high reliability because the tritium concentration in the exhaust gas would be high under plasma operation. Thus, conventional tritium re- moval systems comprising an oxidation catalyst and ab- sorbent such as molecular sieves are applied. A compact system is required due to limited space. A high through- put is required because the maximum flow rate would be 300 Nm 3 /h. Thus, a polymer membrane that can recover
to the alveoli, together with the underlying basement membrane form an effective barrier to prevent pollut- ants and infectious agents such as bacteria and viruses from entering the body . Exposure to air pollutants, both gaseous and PM, can weaken the epithelial barrier, predispose the respiratory system to infections, and fa- cilitate both acute and chronic respiratory disorders . Indeed, fine PM have been shown to lead to a weakened epithelium [7, 8] and are now accepted as a leading con- tributor to chronic respiratory and cardiovascular dis- eases [9, 10].
Cannillo et al.  presented the method for producing Glass–alumina functionally graded materials in two different methods. The first method was percolation, which was representative of natural transport-based processes, and plasma spraying, which was representative of constructive processes. Mohammadi et al.  presented the application of sulfur pipe in sewage pipes, methods of producing these pipes and their comparison. A hot mixture of sulfur and aggregate was provided and used in three methods for this purpose. The first one was casting method, the second Brazing method and the third centrifugal casting. Mohazzab et al.  studied the analytical solution of one-dimensional stresses for a hollow cylinder made of functionally graded material with heat source. Material properties varied continuously across thickness according to power functions of radial direction. The thermal boundary conditions might include conduction, flux and convection for inside or outside of hollow cylinder.
Fig. 7 shows the variation of forward, reflected and absorbed microwave power with the temperature recorded by the probe for catalyst MC-2. The frac- tion of the input power that was reflected dropped from 0.66 at 500 ◦ C to about 0.50 at 650 ◦ C, after which it remained approximately constant. For this reason, only a slight increase in the input power was needed to raise the temperature from 500 to 650 ◦ C. These results would seem to indicate that the effective dielectric loss factor of the catalyst was increasing
The endothelium plays a key role in the control of vascular patency and tone. Thus, the main objective of the study was to determine the role of endothelium and its derived relaxation factors in mediating re- laxation of rat thoracic aorta, in response to sulfurdioxide (SO 2 ) derivatives “1:3 M/M sodium bisulfite