Greenhouse gases abatement by catalytic dry reforming of methane to syngas over samarium oxide-supported cobalt catalyst     

B. V. Ayodele  M. R. Khan  C. K. Cheng 《International Journal of Environmental Science and Technology》2017,14(12):2769-2782

Anthropogenic activities often result in the emissions of methane (CH₄) and carbon dioxide (CO₂) which are the principal components of greenhouse gases. The mitigation of these gases to avert further occurrence of global warming has attracted a lot of research interest. In this study, the potential of greenhouse gases abatement via catalytic CO₂ (dry) reforming of methane to syngas over samarium oxide-supported cobalt (20 wt% Co/80 wt% Sm₂O₃) catalyst was investigated. The 20 wt% Co/80 wt% Sm₂O₃ material was synthesized via wet impregnation method and characterized using different instrument techniques. The methane dry reforming reaction, as well as its kinetics over the catalyst, was studied in a stainless steel fixed-bed continuous flow reactor at feed (CH₄:CO₂) ratios range of 0.1–1.0, temperature range of 923–1023 K and gas hourly space velocity (GHSV) of 30,000 h^?1. The 20 wt% Co/80 wt% Sm₂O₃ catalyst showed promising catalytic activity evident from the highest CH₄ and CO₂ conversion of ~71 and ~74% as well as the highest hydrogen (H₂) and carbon monoxide (CO) yield of ~62 and ~73%, respectively. Moreover, the methane dry reforming over the 20 wt% Co/80 wt% Sm₂O₃ catalyst produces H₂/CO ratio close to unity hence suitable for use as a chemical intermediate for synthesis of oxygenated fuels. The kinetic data obtained from the methane dry reforming were fitted to power law model. Apparent activation energies of 88.62, 80.12, 108.12 and 100.91 kJ mol^?1 were obtained for CH₄, CO₂, H₂ and CO, respectively. The characterization of the spent 20 wt% Co/80 wt% Sm₂O₃ catalyst after 4 h of time-on-stream has confirmed the presence of amorphous carbon which can easily be gasified.  相似文献   

Feasibility,emission and fuel requirement analysis of hybrid car versus solar electric car: a comparative study     

I. Safdar  A. Raza  A. Z. Khan  E. Ali 《International Journal of Environmental Science and Technology》2017,14(8):1807-1818

The problem regarding environment has been considered as contemporary issue, and to cater this, various technologies have been revolutionized in vehicle transport field. Efforts have been made to make vehicle engine efficient and introducing hybridized vehicles with the aim of reducing emissions and less fuel dependency. In essence of this, trends of solar electric cars in different countries have been reviewed. Feasibility analysis is done by doing fuel cost analysis of two cases, i.e., simple hybrid vehicle and hybrid vehicle equipped with solar module and increased battery energy storage capacity for a specific round trip distance between two cities, i.e., Rawalpindi and Islamabad in comparison with feasibility of third case, i.e., proposed solar electric car model. The solar module selection along with desired number of batteries with charging and discharging time and motor power required to carry five persons weight (70 kg each) is calculated for third case. Moreover, total carbon dioxide emission analysis has been carried out from car material production to its assembly, manufacturing solar module and nickel metal hydride battery for each case. The annual carbon dioxide emitted from fuel in first two cases relative to electric outlet in third case for specific distance has been analyzed. On large scale, emission analyses for hundred cars of each case have been done at 100 km distance. From calculations, it is revealed that overall emissions in third case on large scale and from its material production, assembly, solar module and batteries manufacturing perspective are comparatively less than other cases.  相似文献   

Potential of fungus <Emphasis Type="Italic">Trichoderma harzianum</Emphasis> for toxicity reduction in municipal solid waste leachate     

A. K. Awasthi  A. K. Pandey  J. Khan 《International Journal of Environmental Science and Technology》2017,14(9):2015-2022

The purpose of this research was to test the ability of selected fungus Trichoderma harzianum for municipal solid waste leachate treatment. The research carried out by inoculating the enzyme produced by T. harzianum with different ratio (10% up to 80% v/v) of solid waste leachate. The findings clearly indicated that the enzymatic addition was effectively acted (86.09% of chemical oxygen demand removed), and the rate of chemical degradation amended treatment enhanced as compared to control. Also, the enzymatic addition excellently reduced the inhibition of germination (35.8 ± 0.7) of seed (Zea mays L.) and improved the environmental quality of treated leachate. Therefore, these results can be use to articulate the preliminary feedstock for pilot to field-scale application.  相似文献   

Temporal change of glaciers area and geomorphometric parameters in Parbati valley,Himachal Pradesh,India     

Sarfaraz Ahmad  Khatib Khan  Nepal Singh  Zabiullah Ansari  Md. Mulhim 《Environmental Earth Sciences》2017,76(11):407

Temporal change in the glacier coverage is analyzed for the period between 1962 and 2003 in Parbati valley, Himachal Pradesh. It is observed that the total glacier cover has been decreased by 17% ranging between 8 and 100% for individual glacier. The pattern of de-glaciation shows a high degree of shrinkage in outer zone of Parbati valley, while least shrinkage is observed in the inner valley. The present study is conducted to establish relationship between glacio-geomorphic parameters and glaciers shrinkage pattern to predict the future glacier cover in warming scenario. A systematic change is observed for glacio-geomorphic parameters associated with temporal change in glacier cover. It is observed that mean and minimum elevation, slope, relief and duration of insolation have changed substantially. Maximum elevation, plan/profile curvatures and aspect have shown less change from 1962 to 2003. A correlation matrix between glacio-geomorphic parameters for glaciers between 1962 and 2003 shows that the recent glaciers are much more controlled by terrain characteristics than that in the recent past.  相似文献   

Quasi MT Inversion of Short-Offset Transient Electromagnetic Data   总被引：1，自引：0，他引：1  

Wei-ying Chen  Guo-qiang Xue  Muhammad Younis Khan 《Pure and Applied Geophysics》2016,173(7):2413-2422

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Recent developments of the Middle East catalog   总被引：8，自引：2，他引：6  

Mehdi Zare  Hamideh Amini  Pouye Yazdi  Karin Sesetyan  Mine Betul Demircioglu  Dogan Kalafat  Mustafa Erdik  Domenico Giardini  M. Asif Khan  Nino Tsereteli 《Journal of Seismology》2014,18(4):749-772

This article summarizes a recent study in the framework of the Global Earth model (GEM) and the Earthquake Model of the Middle East (EMME) project to establish the new catalog of seismicity for the Middle East, using all historical (pre-1900), early and modern instrumental events up to 2006. According to different seismicity, which depends on geophysical, geological, tectonic, and seismicity data, this region is subdivided to nine subregions, consisting of Alborz–Azerbaijan, Afghanistan–Pakistan, Saudi Arabia, Caucasus, Central Iran, Kopeh–Dagh, Makran, Zagros, and Turkey (Eastern Anatolia; after 30° E). After omitting the duplicate events, aftershocks, and foreshocks by using the Gruenthal method, and uniform all magnitude to Mw scale, 28,244 main events remain for the new catalog of Middle East from 1250 B.C. through 2006. The magnitude of completeness (Mc) was determined as 4.9 for five out of nine subregions, where the least values of Mc were found to be 4.2. The threshold of Mc is around 5.5, 5.0, 4.5, and 4.0, for the time after 1950, 1963, 1975, and 2000, respectively. The average of teleseismic depths in all regions is less than 15 km. Totally, majority of depth for Kopeh–Dagh and Central Iran, Zagros, and Alborz–Azerbaijan, approximately, is 15, 13, and 11 km and for Afghanistan–Pakistan, Caucasus, Makran, Turkey (after 30° E), and Saudi Arabia is about 9 km.  相似文献   

Potential Heavy Metals Accumulation of Indigenous Plant Species along the Mafic and Ultramafic Terrain in the Mohmand Agency,Pakistan          下载免费PDF全文

Mohammad T. Shah  Jamila Ara  Said Muhammad  Sardar Khan  Saeed A. Asad  Liaqat Ali 《洁净——土壤、空气、水》2014,42(3):339-346

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Vortex Assisted Liquid–Liquid Microextraction Using Triton X‐114 for Ultratrace Cadmium Prior to Analysis          下载免费PDF全文

Sumaira Khan  Erkan Yilmaz  Tasneem Gul Kazi  Mustafa Soylak 《洁净——土壤、空气、水》2014,42(8):1083-1088

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Occurrences of damaging earthquakes between the Himachal and Darjeeling Himalayas: Tectonic implications     

Md. Afroz Ansari  Prosanta K. Khan 《Acta Geophysica》2014,62(4):699-736

Detailed analysis of intensity for ten damaging historical earthquakes in the central arcuate belt between the Himachal and Darjeeling Himalayas was carried out in the backdrop of isoseismal eccentricity, source depth and Indian plate obliquity. Results indicate that the elongated axes of the isoseismals and strike of ruptures for shallow earthquakes are almost parallel with strike of the Himalayan arc, and clearly conformable with the obliquity. An empirical power law relationship between eccentricity and focal depth established under the present study illustrates that the deeper events are more influenced by the bending of the penetrating Indian lithosphere, whereas the shallower events are principally controlled by the obliquity. A positive correlation between eccentricities and obliquity obviously supports this inference. The present study further reveals that the constant decrease in Indian plate obliquity from Himachal to Nepal-Bihar Himalaya is well compatible with the graben structures and horizontal shearing along this arcuate segment.  相似文献   

Sea Level Variations and Geomorphological Changes in the Coastal Belt of Pakistan     

Tariq Masood Ali Khan  D. A. Razzaq  Qamar-Uz-Zaman Chaudhry  Dewan Abdul Quadir  Anwarul Kabir  Majajul Alam Sarker 《Marine Geodesy》2013,36(1-2):159-174

The UNEP in its regional seas program in 1989 has included Pakistan in a group of countries which are vulnerable to the impact of rising sea level. If the present trend of sea level rise (SLR) at Karachi continues, in the next 50 years the sea level rise along the Pakistan Coast will be 50 mm (5 cm). Since the rising rates of sea level at Karachi are within the global range of 1-2 mm/year, the trends may be treated as eustatic SLR. Historical air temperature and sea surface temperature (SST) data of Karachi also show an increasing pattern and an increasing trend of about 0.67°C has been registered in the air temperature over the last 35 years, whereas the mean SST in the coastal waters of Karachi has also registered an increasing trend of about 0.3°C in a decade. Sindh coastal zone is more vulnerable to sea level rise than Baluchistan coast, as uplifting of the coast by about 1-2 mm/year due to subduction of Indian Ocean plate is a characteristic of Baluchistan coast. Within the Indus deltaic creek system, the area nearby Karachi is more vulnerable to coastal erosion and accretion than the other deltaic region, mainly due to human activities together with natural phenomena such as wave action, strong tidal currents, and rise in sea level. Therefore, The present article deals mainly with the study of dynamical processes such as erosion and accretion associated with sea level variations along the Karachi coast and surrounding Indus deltaic coastline. The probable beach erosion in a decade along the sandy beaches of Karachi has been estimated. The estimates show that 1.1 mm/year rise in sea level causes a horizontal beach loss of 110 mm per year. Therefore, coast eroded with rise in sea level at Karachi and surrounding sandy beaches would be 1.1 m during a period of next 10 years. The northwestern part of Indus delta, especially the Gizri and Phitti creeks and surrounding islands, are most unstable. Historical satellite images are used to analyze the complex pattern of sediment movements, the change in shape of coastline, and associated erosion and accretion patterns in Bundal and Buddo Islands. The significant changes in land erosion and accretion areas at Bundal and Buddo Islands are evident and appear prominently in the images. A very high rate of accretion of sediments in the northwestern part of Buddo Island has been noticed. In the southwest monsoon season the wave breaking direction in both these islands is such that the movement of littoral drift is towards west. Erosion is also taking place in the northeastern and southern part of Bundal Island. The erosion in the south is probably due to strong wave activities and in the northeast is due to strong tidal currents and seawater intrusion. Accretion takes place at the northwest and western parts of Bundal Island. By using the slope of Indus delta, sea encroachment and the land area inundation with rising sea level of 1 m and 2 m have also been estimated.  相似文献