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371.
On the heating environment in street canyon 总被引:1,自引:1,他引:0
This study investigates the impact of building aspect ratio (building-height-to-street-canyon-width-ratio), wind speed and
surface and air-temperature difference (Δθs−a) on the heating environment within street canyon. The Reynolds-averaged Navier-Stokes (RANS) and energy transport equations
were solved with Renormalization group (RNG) theory version of k-e{\varepsilon} turbulence model. The validation process demonstrated that the model could be trusted for simulating air-temperature and
velocity trends. The temperature and velocity patterns were discussed in idealized street canyons of different aspect ratios
(0.5–2.0) with varying ambient wind speeds (0.5–1.5 m/s) and Δθs−a (2–8 K). Results show that air-temperatures are directly proportional to bulk Richardson number (R
b
) for all but ground heating situation. Conversely, air-temperatures increase significantly across the street canyon with
a decrease in ambient wind speed; however, the impact of Δθs−a was negligible. Clearly, ambient wind speed decreases significantly as it passes over higher AR street canyons. Notably,
air-temperatures were the highest when the windward wall was heated and the least during ground heating. Conversely, air-temperatures
were lower along the windward side but higher within the street canyon when the windward wall was heated. 相似文献
372.
M. Waseem Mumtaz Ahmad Adnan Hamid Mukhtar Khalid Nawaz Ahtisham Raza Zahoor Ahmad 《Environmental monitoring and assessment》2011,172(1-4):581-587
The present work deals with the assessment of bacteriological contamination along with some physico-chemical parameters of water samples from Lahore canal. ANOVA showed that the observed p values of log-transformed viable plate counts, total suspended solids, turbidity, and biological oxygen demand are 0.000, 0.000, 0.000, and 0.000, respectively, which are <0.05, while the p value of total coliforms, total fecal coliforms, and Escherichia coli are 0.728, 0.827, and 0.081, respectively which are >0.05. Significant correlation was observed between log-transformed viable plate counts (CFU), biological oxygen demand, total suspended solids, and turbidity. Further regression analysis revealed that simple line regression model is fit for log-transformed viable plate counts and total suspended solids, log-transformed viable plate counts and turbidity, turbidity and total suspended solids, biological oxygen demand and total suspended solids, biological oxygen demand and log-transformed viable plate counts, and biological oxygen demand and turbidity. 相似文献
373.
Faruque Ahmed M. Hawa Bibi Takehiko Fukushima Koji Seto Hiroaki Ishiga 《Environmental monitoring and assessment》2011,173(1-4):167-180
A geochemical study of the bottom sediments of Lake Shinji and the River Ohashi in southwestern Japan was carried out to determine their elemental compositions and to evaluate the pollution status of lake sediments by employing enrichment factor (EF), pollution load index (PLI), and geoaccumulation index (I geo). Present-day water quality was also assessed. Results showed that the water quality of Lake Shinji contrasts slightly between the upper and lower parts. The chemical composition of the sediments, as measured by X-ray fluorescence, included major and trace elements and total sulfur (TS). Average abundances of As, Pb, Zn, Cu, Ni, and Cr in the Shinji sediments were 10, 29, 143, 27, 19, and 54 ppm, respectively, compared to 6, 18, 57, 16, 10, and 37 ppm in the river sediments. Based on the EF, PLI, and I geo, the lake sediments are moderately to strongly polluted with respect to As, moderately polluted with Pb, Zn, and Cr, and unpolluted with Cu and Ni. The high EF and I geo for As, Pb, and Zn in the lake sediments indicate that metal concentration has occurred in Shinji. Increases in the abundances of these metals are likely related to the fine-grained nature of the sediments, reducing conditions of the bottom sediments, enrichment in organic matter, and possibly a minor contribution from non-point anthropogenic sources. Trace metal contents are strongly correlated with Fe2O3 and TS, suggesting that Fe oxides and sulfides play a role in controlling abundances in the investigated areas. 相似文献
374.
Distribution and solid-phase speciation of toxic heavy metals of bed sediments of Bharali tributary of Brahmaputra River 总被引:1,自引:0,他引:1
Raza Rafiqul Hoque K. G. Goswami B. C. Kusre K. P. Sarma 《Environmental monitoring and assessment》2011,177(1-4):457-466
Heavy metal (Fe, Mn, Zn, Cu, Ni, Pb, and Cd) concentrations and their chemical speciations were investigated for the first time in bed sediments of Bharali River, a major tributary of the Brahmaputra River of the Eastern Himalayas. Levels of Fe, Mn, Pb, and Cd in the bed sediments were much below the average Indian rivers; however, Cu and Zn exhibit levels on the higher side. Enrichment factors (EF) of all metals was greater than 1 and a higher trend of EF was seen in the abandoned channel for most metals. Pb showed maximum EF of 32 at site near an urban center. The geoaccumulation indices indicate that Bharali river is moderately polluted. The metals speciations, done by a sequential extraction regime, show that Cd, Cu, and Pb exhibit considerable presence in the exchangeable and carbonate fraction, thereby showing higher mobility and bioavailability. On the other hand, Ni, Mn, and Fe exhibit greater presence in the residual fraction and Zn was dominant in the Fe?CMn oxide phase. Inter-species correlations at three sites did not show similar trends for metal pairs indicating potential variations in the contributing sources. 相似文献
375.
Ahmed MK Parvin E Arif M Islam MM Akter MS Khan MS 《Environmental monitoring and assessment》2011,182(1-4):197-204
The present investigation was undertaken to study the induction of DNA damage by lead chloride (PbCl(2)) in freshwater climbing perch Anabas testudineus using alkaline single cell gel electrophoresis (comet assay). Based on the LC(50) values of lead chloride of A. testudineus three different concentrations viz., 0.1, 1.0 and 2.0 mg/L were selected to expose fish. The DNA damage was observed in the gill, kidney and liver tissue as the percentage of DNA in comet tails and comet heads in the tissue of the exposed fish. DNA damage at different concentrations showed sensitivity to particular tissue. The liver tissue exhibited significantly (p < 0.01) higher DNA damage, followed by kidney and gill. However, the DNA damage was found to be dose dependent; at 2 mg/L of PbCl(2) the tail and head DNA of liver tissue were 57.84% and 39.49%, in kidney tissue the values were 52.36% and 44.97% whereas in gill tissue the values were 48.86% and 48.96% respectively. The current study explored the utility of the comet assay for in vivo laboratory studies using A. testudineus species for screening the genotoxic potential of lead chloride. 相似文献
376.
Ghrefat HA Jamarh A Al-Futaisi A Al-Abri B 《Environmental monitoring and assessment》2011,181(1-4):509-524
There are more than 4,000 falaj (singular of a peculiar dug channel) distributed in different regions in Oman. The chemical characteristics of the water in 42 falaj were studied to evaluate the major ion chemistry; geochemical processes controlling water composition; and suitability of water for drinking, domestic, and irrigation uses. GIS-based maps indicate that the spatial distribution of chemical properties and concentrations vary within the same region and the different regions as well. The molar ratios of (Ca + Mg)/Total cations, (Na + K)/Total cations, (Ca + Mg)/(Na + K), (Ca + Mg)/(HCO? + SO?), and Na/Cl reveal that the water chemistry of the majority of aflaj are dominated by carbonate weathering and evaporite dissolution, with minor contribution of silicate weathering. The concentrations of most of the elements were less than the permissible limits of Omani standards and WHO guidelines for drinking water and domestic use and do not generally pose any health and environmental problems. Some aflaj in ASH Sharqiyah and Muscat regions can be used for irrigation with slight to severe restriction because of the high levels of electrical conductivity, total dissolved solids, chloride, and sodium absorption ratio. 相似文献
377.
Khaskheli Asadullah Jiang Yushi Raza Syed Ali Khan Komal Akram Qureshi Muhammad Asif 《Environmental science and pollution research international》2021,28(21):26449-26460
Environmental Science and Pollution Research - Environmental degradation has severely affected the natural cycle of ecosystem. It’s high time now and humans should execute strategies... 相似文献
378.
Ahmad Munir Chandio Abbas Ali Solangi Yasir Ahmed Shah Syed Ahsan Ali Shahzad Farrukh Rehman Abdul Jabeen Gul 《Environmental science and pollution research international》2021,28(2):1502-1518
Environmental Science and Pollution Research - This research investigates the dynamic interactive associations among sustainable investment in the energy sector, air pollution, and sustainable... 相似文献
379.
Ben Said Myriam Bousselmi Latifa Ghrabi Ahmed 《Environmental science and pollution research international》2021,28(13):15819-15827
Environmental Science and Pollution Research - In this study, we propose the development of a rapid and reliable method to control and to monitor microbial water quality. The methylene blue (MB)... 相似文献
380.
Usmani Muhammad Shahjahan Wang Jianling Ahmad Naveed Iqbal Muzaffar Ahmed Rahil Irfan 《Environmental science and pollution research international》2021,28(23):28848-28864
Environmental Science and Pollution Research - This study presents a comprehensive literature review and gives an insight into the increasing research trends that are based on the discipline of... 相似文献