Characteristics of the dust-plasma interaction near Enceladus’ South Pole     

Muhammad Shafiq  J.-E. Wahlund  W.S. Kurth 《Planetary and Space Science》2011,59(1):17-25

We present RPWS Langmuir probe data from the third Enceladus flyby (E3) showing the presence of dusty plasma near Enceladus’ South Pole. There is a sharp rise in both the electron and ion number densities when the spacecraft traverses through Enceladus plume. The ion density near Enceladus is found to increase abruptly from about 10² cm⁻³ before the closest approach to 10⁵ cm⁻³ just 30 s after the closest approach, an amount two orders of magnitude higher than the electron density. Assuming that the inconsistency between the electron and ion number densities is due to the presence of dust particles that are collecting the missing electron charges, we present dusty plasma characteristics down to sub-micron particle sizes. By assuming a differential dust number density for a range in dust sizes and by making use of Langmuir probe data, the dust densities for certain lower limits in dust size distribution were estimated. In order to achieve the dust densities of micrometer and larger sized grains comparable to the ones reported in the literature, we show that the power law size distribution must hold down to at least 0.03 μm such that the total differential number density is dominated by the smallest sub-micron sized grains. The total dust number density in Enceladus’ plume is of the order of 10² cm⁻³ reducing to 1 cm⁻³ in the E-ring. The dust density for micrometer and larger sized grains is estimated to be about 10⁻⁴ cm⁻³ in the plume while it is about 10⁻⁶-10⁻⁷ cm⁻³ in the E-ring. Dust charge for micron sized grains is estimated to be about eight thousand electron charges reducing to below one hundred electron charges for 0.03 μm sized grains. The effective dusty plasma Debye length is estimated and compared with inter-grain distance as well as the electron Debye length. The maximum dust charging time of 1.4 h is found for 0.03 μm sized grains just 1 min before the closest approach. The charging time decreases substantially in the plume where it is only a fraction of a second for 1 μm sized grains, 1 s for 0.1 μm sized grains and about 10 s for 0.03 μm sized grains.  相似文献   

Identification of the Phytoremediation Potential of Indian mustard Genotypes for Copper,Evaluated from a Hydroponic Experiment     

Mohd. Kafeel Ahmad Ansari  Elif Oztetik  Altaf Ahmad  Shahid Umar  Muhammad Iqbal  Gary Owens 《洁净——土壤、空气、水》2013,41(8):789-796

The effectiveness of 10 Indian mustard (Brassica juncea L.) genotypes (viz. Agrani, BTO, Kranti, Pusa Bahar, Pusa Basant, Pusa Bold, Pusa Jai Kisan, Vaibhav, Vardhan, and Varuna) were evaluated for their potential to phytoremediate copper from contaminated waters under laboratory controlled conditions. The genotypes were grown for 20 days in aqueous solutions containing various concentrations of copper sulfate (0–50 µM) in a hydroponic chamber. Throughout plant development, changes in growth variables, biomass accumulation, and total Cu content were evaluated. The results suggested that Indian mustard cv. Pusa Jai Kisan possesses the best capacities of Cu sequestration and tolerance amongst all the genotypes studied. Thus, Pusa Jai Kisan has the greatest potential to become a viable candidate in the development of practical phytoremediation technologies for Cu contaminated sites.  相似文献   

Building resilience to natural hazards in Indonesia: progress and challenges in implementing the Hyogo Framework for Action   总被引：1，自引：0，他引：1  

Riyanti Djalante  Frank Thomalla  Muhammad Sabaruddin Sinapoy  Michelle Carnegie 《Natural Hazards》2012,62(3):779-803

Over the last 50?years, the cost of natural disasters has increased globally and in Indonesia (EM-DAT 2012). We therefore need more systematic efforts in trying to reduce disaster risks. In 2005, the United Nations International Strategy for Disaster Reduction created the Hyogo Framework for Action (HFA) 2005?C2015: ??Building the Resilience of Nations and Communities??, in order to enable a more systematic planning, implementation and evaluation of disaster risk reduction (DRR) activities. In this paper, we examine Indonesia??s success in improving DRR by reviewing the country??s progress in implementing the HFA Priorities for Actions. This includes an analysis of the drivers, challenges and emerging issues in building resilience to natural hazards. The study is undertaken through literature reviews and interviews with 26 representatives of key organisations in DRR and climate change adaptation (CCA) in Indonesia. Our findings indicate that the building disaster resilience in Indonesia has been, to a large extent, driven by the existence of the necessary regulatory policies and frameworks and the participation of various non-government stakeholders. Impediments to process include a lack of capacity and capability for DRR at the local government level, a lack of systematic learning and a lack of commitment from government to mainstream DRR into broader development agendas. Emerging pressing issues that are likely to challenge future resilience building activities include the integration of DRR and CCA and urban risk governance.  相似文献   

Comparison of Early Succession and Scleractinian Recruitment Between Artificial Live Rocks and Terracotta Tiles     

Hamizan  Yusof Muhammad  Saad  Shahbudin  Naim  Mohd Azrul  Khodzori  Mohd Fikri Akmal  Hanapiah  Muhammad Faiz Mohd 《Ocean Science Journal》2021,56(3):317-325

Ocean Science Journal - Previous studies indicated that artificial live rock (ALR) has the potential to be used as a substrate for coral juveniles. The present study reported a potential of ALR as...  相似文献   

Landslide dam and subsequent dam-break flood estimation using HEC-RAS model in Northern Pakistan   总被引：1，自引：0，他引：1  

Mohsin Jamil Butt  Muhammad Umar  Raheel Qamar 《Natural Hazards》2013,65(1):241-254

On the morning of January 4, 2010, a massive landslide swept the Attabad and Sarat villages into the Hunza River. The debris from the landslide blocked the low-lying river, creating a barrier lake in the area and poses a major threat to the villages located downstream. The aim of the current study was to evaluate the environmental advantages and disadvantages created by the formation of the artificial lake. For this purpose, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data were used to create the contours and triangulated irregular network (TIN) of the region. Data from ??Google Earth?? image on March 19, 2010 were used as the reference and to determine the river bed elevation of the study area. Landsat satellite data of Enhanced Thematic Mapper Plus (ETM+) sensor on January 10, March 15, April 24 and May 2, 2010, were used for constructing the Geographic Information System (GIS) layers of the river banks, land use area, overbank flow area and water area estimation. Our results show that the area covered by the water in the lake has increased from 1.28?km² on January 10, 2010 to 6.25?km² on May 2, 2010. The total upstream urban area affected by the river blockage is 13.99?km². We also applied the Hydrologic Engineering Center River Analysis System (HEC-RAS) model to estimate the potential catastrophes due to dam burst for different peak outflow scenarios with conclusions and recommendations.  相似文献   

Extracting the damaging effects of the 2010 eruption of Merapi volcano in Central Java, Indonesia   总被引：1，自引：1，他引：0  

Fajar Yulianto  Parwati Sofan  Muhammad Rokhis Khomarudin  Muhammad Haidar 《Natural Hazards》2013,66(2):229-247

This research focuses on providing information related to the damaging effects of the 2010 eruption of Merapi volcano in Central Java, Indonesia. This information will be used to help emergency responders to assess losses more timely and efficiently, and to monitor the progress in emergency response and recovery. The objectives of this research are: (a) to generate a map of pyroclastic deposits based on activities pre- and post-volcano eruption of 2010 in the research area, (b) to investigate the impact of volcano eruption on the environment, and (c) to assess the impact of volcano eruption on landuse. ALOS PALSAR remote sensing data pre- and post-disaster were used in this research for mapping the volcano eruption. Topographic and geomorphological maps were analyzed for profiling and field orientation, which were used to investigate the impact of volcano eruption on the environment. SPOT 4 satellite images were used in this research for updating landuse information from the topographic map. The result of the landuse updated data was used for assessment of the volcano eruption’s impact on landuse with the GIS raster environment. The volcanic eruption that occurred in 2010 is estimated to have an impact of 133.31 ha for settlements, 92.32 ha for paddy fields, 235.60 ha for dry farming, 570.98 ha for plantations, 380.86 ha for bare land, and 0.12 ha for forest areas. An estimate of the number of buildings damaged due to the volcano eruption in 2010 was carried out by overlaying a map of pyroclastic deposits and the information point of the building sites from the topographic map. The total number of buildings damaged is estimated to be around 12,276 units.  相似文献   

Characterization and Purification of Membrane‐Bound Azoreductase From Azo Dye Degrading Shewanella sp. Strain IFN4          下载免费PDF全文

Muhammad Imran  Fayek Negm  Sabir Hussain  Muhammad Ashraf  Muhammad Ashraf  Zulfiqar Ahmad  Muhammad Arshad  David E. Crowley 《洁净——土壤、空气、水》2016,44(11):1523-1530

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Error minimization of polynomial approximation of Delta T     

Islam Sana  Sadiq Muhammad  Qureshi Muhammad Shahid 《Journal of Astrophysics and Astronomy》2008,29(3-4):363-366

The difference between Universal time (UT) and Dynamical time (TD), known as Delta T (ΔT) is tabulated for the first day of each year in the Astronomical Almanac. During the last four centuries it is found that there are large differences between its values for two consecutive years. Polynomial approximations have been developed to obtain the values of ΔT for any time of a year for the period AD 1620 to AD 2000 (Meeu 2000) as no dynamical theories describe the variations in ΔT. In this work, a new set of polynomials for ΔT is obtained for the period AD 1620 to AD 2007 that is found to produce better results compared to previous attempts.  相似文献   

Predictability performance enhancement for suspended sediment in rivers:Inspection of newly developed hybrid adaptive neuro-fuzzy system model     

Rana Muhammad Adnan  Zaher Mundher Yaseen  Salim Heddam  Shamsuddin Shahid  Aboalghasem Sadeghi-Niaraki  Ozgur Kisi 《国际泥沙研究》2022,37(3):383-398

Reliable modeling of river sediments transport is important as it is a defining factor of the economic viability of dams, the durability of hydroelectric-equipment, river susceptibility to pollution, suitability for navigation, and potential for aesthetics and fish habitat. The capability of a new machine learning model, fuzzy c-means based neuro-fuzzy system calibrated using the hybrid particle swarm optimization-gravitational search algorithm（ANFIS-FCM-PSOGSA） in improving the estimation accur...  相似文献   

Assessment of Heavy Metal Contamination in Soil and Groundwater at Leather Industrial Area of Kasur,Pakistan   总被引：1，自引：0，他引：1       下载免费PDF全文

Muhammad Afzal  Ghulam Shabir  Samina Iqbal  Tanveer Mustafa  Qaiser Mahmood Khan  Zafar Mahmood Khalid 《洁净——土壤、空气、水》2014,42(8):1133-1139

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