Effect of a Non‐Ionic Surfactant on Xylene Removal in a Scoria‐Compost‐Based Biofilter          下载免费PDF全文

Mohammad Mehdi Amin  Amir Rahimi  Bijan Bina  Fazel Mohammadi Moghadam  Heshmatollah Nourmoradi  Mohsen Heidari 《洁净——土壤、空气、水》2016,44(12):1759-1765

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The Gulf: A young sea in decline     

Charles Sheppard  Mohsen Al-Husiani  Faiza Al-Yamani  James Bishop  Eric Dutrieux  Subba Rao V. Durvasula  Ron Loughland  M. Nithyanandan  Igor Polikarpov  Sam Purkis  Maria Saburova  Oliver Taylor  Khadija Zainal 《Marine pollution bulletin》2010,60(1):13-38

This review examines the substantial changes that have taken place in marine habitats and resources of the Gulf over the past decade. The habitats are especially interesting because of the naturally high levels of temperature and salinity stress they experience, which is important in a changing world climate. However, the extent of all natural habitats is changing and their condition deteriorating because of the rapid development of the region and, in some cases from severe, episodic warming episodes.Major impacts come from numerous industrial, infrastructure-based, and residential and tourism development activities, which together combine, synergistically in some cases, to cause the observed deterioration in most benthic habitats. Substantial sea bottom dredging for material and its deposition in shallow water to extend land or to form a basis for huge developments, directly removes large areas of shallow, productive habitat, though in some cases the most important effect is the accompanying sedimentation or changes to water flows and conditions. The large scale of the activities compared to the relatively shallow and small size of the water body is a particularly important issue.Important from the perspective of controlling damaging effects is the limited cross-border collaboration and even intra-country collaboration among government agencies and large projects. Along with the accumulative nature of impacts that occur, even where each project receives environmental assessment or attention, each is treated more or less alone, rarely in combination. However, their combination in such a small, biologically interacting sea exacerbates the overall deterioration. Very few similar areas exist which face such a high concentration of disturbance, and the prognosis for the Gulf continuing to provide abundant natural resources is poor.  相似文献   

Paleoseismological Analysis Along the Astara Fault System (Talesh Mountain, North Iran)     

Amir BARZEGARI  Manouchehr GHORASHI  Hamid NAZARI  Michel FONTUGNE  Mohammad A. SHOKRI  Mohsen POURKERMANI 《《地质学报》英文版》2017,91(5):1553-1572

The Astara Fault System(AFS) is located in the northwest Alborz, east of Talesh Mountain(TM) and west of the South Caspian Basin(SCB). The AFS is one of the basement rock faults in Iran that is heavily involved in seismotectonic activity of the Talesh region, and to which subsidence of the SCB is attributed. There is little information available concerning previous AFS seismic activities and its properties. In order to elucidate the seismic behavior and activities of the AFS, we conducted a research study on paleoseismology of the fault. Based on paleoseismic evidence, two scenarios could be taken into consideration, one of which has three and another has four seismic events with magnitudes Mw in the range of 6.7 to 7.2. Evidence of these seismic events is within sedimentary succession as they have occurred during the past 3 ka(this age is determined based on the deposition rate of the region). Six carbon samples were taken for C~(14) age determination tests, the results of which clearly demonstrated that the EvIV(scenario A) and EvⅢ(scenario B) had occurred before 27,444 cal BP, while other events occurred in the time period between 27,444 cal BP and 3 ka ago. If we consider the occurrence of three or four seismic events(based on the two scenarios) to be between 27,444 cal BP and 3 ka ago, the average recurrence interval is 7,119 ± 1,017, but evidence for these events has been removed. If we assume EvI to be the youngest event(in both scenarios), the minimum elapsed time is therefore 3 ka.  相似文献   

Metal fractionation and pollution risk assessment of different sediment sizes in three major southwestern rivers of Caspian Sea     

Ali Vosoogh  Mohsen Saeedi  Raziyeh Lak 《Environmental Earth Sciences》2017,76(7):292

To assess the risk of release and percentage of heavy metals in river sediment, nine stations were set up to sample surface sediments from three important rivers situated southwest of the Caspian Sea (the Shafaroud, Karaganroud, and Choubar Rivers). Chemical analyses were conducted on sediment with particle sizes of >38, 63–38, 63–125, 125–250, 250–500 and 500–1000 µm using metal fractionation to determine the degree of risk release and the heavy metal pollution. Common risk indices were used including the cumulative indices of pollution intensity assessment and risk release standards (the modified pollution degree and ecological risk). Generally, when sediment sizes are decreased, the concentration of heavy metals is both larger and greater than the mean concentration of global sediments and earth crust. However, in this research, the concentration of all the metals did not necessarily increase with a decrease in the size of particles. In fact, concentration of cobalt, vanadium, cadmium, and chromium was greater in sediment particle sizes over 63 μm. The results of chemical fractionation analyses indicated that the release risk of metals has two initial phases for: (1) exchangeable bond (F1) and (2) carbonated bond (F2). When compared with other metals, nickel had the greatest tendency to bond within the loose exchangeable phase (F1) across all the stations. Furthermore, with changes in the size of particles, the percentage of heavy metal changes across different bond phases, but will be the greatest in the loose exchangeable phase (F1). This was observed with cobalt, nickel, and chromium at particle sizes larger than 63 μm. The results of ecological risk and modified pollution degree indices indicated that the highest level of pollution was related to sediments with sizes between 63 and 250 μm. Eventually, in order to assess the risk extent of metals present in sediment, a cumulative index referred to as the modified risk assessment code was utilized. It suggested that the greatest risk of toxicity in some stations has been related to particles larger than 63 μm.  相似文献   

Strategies for improving land delivery for residential development: a case of the north-west metropolitan Melbourne     

Seungyeon Ji  Muyiwa Agunbiade  Mohsen Kalantari 《International journal of geographical information science》2013,27(9):1649-1667

One of the factors affecting the housing supply is closely linked to the time taken to complete the land development assessment approval. Delays in completing the development process on time often results in difficulties of increasing housing supply. In parallel, housing demand continues to increase with increasing net population in Australian urban areas. This research aims to identify the current issues and challenges of releasing land for housing development in the established suburbs of Melbourne north-west area (involving six local government areas: Brimbank, Maribyrnong, Moreland, Moonee Valley, Hume and Melton). An application of multi-criteria decision making (MCDM) using the strategic residential potential assessment (SRPA) method is considered. This is designed to improve the method of land administration strategies for housing development. The analysis is set within the context of investigating land preparation processes and their impacts on land availability for housing supply. The research adopts interview techniques to gain insight into the processes of land release through the activities of town planners in the selected local council areas. The proposed SRPA methods are based on a land-use assessment approach that is underpinned by the current residential land-use schemes legislated by the Department of Transport Planning and Local Infrastructure.¹ The results of applying the proposed model reveal the associated spatial pattern of areas with potential for residential development relative to the public transport and public service locations.  相似文献   

Geochemistry and Radioactive Potentiality of Um Naggat Apogranite, Central Eastern Desert, Egypt     

Adel H. EL–AFANDY  Hamdy M. ABDALLA  Mohsen M. ALY  Fathy AMMAR 《Resource Geology》2000,50(1):39-51

Abstract: The northern part of Um Naggat granite massif (UNGM) has suffered extensive post-magmatic metasomatic reworking which results into the development of (Zr, Hf, Nb, Ta, U, Th, F)– and albite-enriched and greisenized apogranite body (UNAP) of 600 m thick, and more than 3 km in the strike length.
Albitization produced an enrichment in Zr (av. 2384 ppm), Hf (61), Nb (419), and U (43). The Th/U ratio ranges between 1. 33 and 1. 90. Extreme albitization (i. e. the albitite rock) is characterized by sharp decrease in the rare metals contents. However, extreme greisenization (i. e. endogreisen bodies) is characterized by a considerable enrichment in Zr (av. 5464 ppm), Hf (143), Nb (2329), Ta (152), U (66) and Th (178). The Th/U ratio ranges between 1. 57 and 3. 60. In contrast to extreme greisenization, it seems that extreme albitization does not apparently change the fluid pH and therefore poor amounts of rare metals are localized in the albitites.
It is suggested that the presence of Na⁺, H⁺ and F^- in the ore fluids was essential to stablize complexes of Zr, Hf, Nb, Ta, U, Th, and HREE during extraction and transportation. In contrast, contemporaneous decrease of temperature and increasing pH due to decreasing pressure are considered the essential factors for localization of disseminated mineralization of Zr and Nb in the apical parts of the UNAP. The enhanced uranium content in the alteration facies of UNAP coupled with the absence of significant uranium mineralization may indicate the metalliferous rather than mineralized nature for the UNAP. The high uranium contents are stabilized in refractory accessory minerals. However, with repect to Zr and Nb, the UNAP especially the albitized and greisen facies, can be categorized as a mineralized productive granite.  相似文献   

Evaluation of energy balance closure adjustment methods by independent evapotranspiration estimates from lysimeters and hydrological simulations          下载免费PDF全文

Matthias Mauder  Sandra Genzel  Jin Fu  Ralf Kiese  Mohsen Soltani  Rainer Steinbrecher  Matthias Zeeman  Tirtha Banerjee  Frederik De Roo  Harald Kunstmann 《水文研究》2018,32(1):39-50

Non‐closure of the surface energy balance is a frequently observed phenomenon of hydrometeorological field measurements, when using the eddy‐covariance method, which can be ascribed to an underestimation of the turbulent fluxes. Several approaches have been proposed in order to adjust the measured fluxes for this apparent systematic error. However, there are uncertainties about partitioning of the energy balance residual between the sensible and latent heat flux and whether such a correction should be applied on 30‐min data or longer time scales. The data for this study originate from two grassland sites in southern Germany, where measurements from weighable lysimeters are available as reference. The adjusted evapotranspiration rates are also compared with joint energy and water balance simulations using a physically based distributed hydrological model. We evaluate two adjustment methods: the first one preserves the Bowen ratio and the correction factor is determined on a daily basis. The second one attributes a smaller portion of the residual energy to the latent heat flux than to the sensible heat flux for closing the energy balance for every 30‐min flux integration interval. Both methods lead to an improved agreement of the eddy‐covariance based fluxes with the independent lysimeter estimates and the physically based model simulations. The first method results in a better comparability of evapotranspiration rates, and the second method leads to a smaller overall bias. These results are similar between both sites despite considerable differences in terrain complexity and grassland management. Moreover, we found that a daily adjustment factor leads to less scatter than a complete partitioning of the residual for every half‐hour time interval. The vertical temperature gradient in the surface layer and friction velocity were identified as important predictors for a potential future parameterisation of the energy balance residual.  相似文献   

A new solution to estimate the time delay on the topographic site using time domain 3D boundary element method     

Tarinejad  Reza  Isari  Mohsen  Sohrabi-Bidar  Abdollah 《地震工程与工程振动(英文版)》2020,19(3):611-623

This study focuses on investigating spatial variation of ground motion that has great influence on the dynamic behavior of the large structures located on the surface topography. One of the most effective parameters on the spatial variation of ground motion is the difference between the arrival time of seismic waves in different points located on the abutments. In this research, a three-dimensional model of the Pacoima Dam site is prepared. The time domain 3 D boundary element method is used to apply non-uniform excitation at the dam supports. This model is subjected to vertically propagating incident SH and P waves. The time delay can be characterized by calculating the value of the time delay for which the cross-correlation between two records is maximized. Finally, to obtain the time delay in a topographic site, a function considering effective parameters such as the height from the canyon base, wave velocity and predominant frequency, is presented. Furthermore, a code was developed for generating the spatially variation of seismic ground motions. The results show that the proposed functions have an acceptable accuracy in estimating the time delay to generate non-uniform ground motion.  相似文献   

Evolutionary Prediction of Biohydrogen Production by Dark Fermentation     

Azam Akhbari  Shaliza Ibrahim  Ali A. Zinatizadeh  Hossein Bonakdari  Isa Ebtehaj  Zohre S. Khozani  Mohsen Vafaeifard  Bahram Gharabaghi 《洁净——土壤、空气、水》2019,47(1)

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Monitoring hawksbill turtle nesting sites in some protected areas from the Persian Gulf     

Hesni Majid Askari  Rezaie-Atagholipour Mohsen  Zangiabadi Somaye  Tollab Mohammad Amin  Moazeni Mostaf  Jafari Hosein  Matin Mohammad Talebi  Zafarani Ghasem Ghorbanzadeh  Shojaei Maht  Motlaghnejad Abbas 《海洋学报(英文版)》2019,38(12):43-51

Iranian nesting populations of the critically endangered hawksbill turtle(Eretmochelys imbricate) are some of the most important in the Indian Ocean. In this study, four of the most important hawksbill nesting grounds in the Persian Gulf, situated within three Iranian marine protected areas, were surveyed during nesting season,including Nakhiloo, Ommolgorm and Kharko Islands and the mainland beaches of the Naiband Marine-Coastal National Park(NMCNP). We present GIS maps of these key nesting grounds and describe sand texture of key nesting zones, along with conservation recommendations. About 9.2(28.3%) out of 32.5 km of all shores surveyed in this study were used by nesting hawksbill turtles follows: Nakhiloo: 1.4 km(52% of potential nesting area);Ommolgorm: 1.94 km(40%); Kharko: 3.4 km(28%), and NMCNP: 2.46 km(18.9%). The average nesting density was calculated as 131 nests/km at Nakhiloo, 76 nests/km at Ommolgorm, 7 nests/km at Kharko, and 15 nests per km at NMCNP. Highest nesting density was observed in Nakhiloo and Ommolgorm. It is thought that high hawksbill nesting density in these islands seems likely a result of limiting adequate nesting shores rather than the size of population, and also low density in Kharko and NMCNP more related to past and current pressures and low population density. With the exception of Ommolgorm Island, sands at the nesting grounds were well sorted.Grain size indicated that female hawksbill turtles in the Iranian Persian Gulf nest in sands that are generally mixed, with mean grain size ranging from coarse sands(0.4Φ;～0.5–1 mm) to fine sands(2Φ;～0.25 mm). We provide and discuss conservation recommendations and suggestions for future.  相似文献