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171.
Salih Muhammad Awadh Zenah Saleem Abood Murtadha Jabar Eisa 《Arabian Journal of Geosciences》2013,6(10):3765-3772
The caves that are present within the Injana Formation (Upper Miocene–Pliocene) which sometimes extend to be hosted within the Dibdibba Formation (Pliocene–Pleistocene) in the Tar Al-Najaf and Tar Al-Sayyed within the Najaf–Karbala district have been studied. The study aims to assess the genesis of caves and diagnose the factors affecting the building and the destruction of these caves through geologic time. For this reasons, intensive fieldwork as well as the mineralogical composition and microscopic interpretation were achieved to facilitate the investigation of cave-forming factors. Calcite, quartz, feldspar, dolomite, as well as clay minerals are the constituents of Injana Formation in the study area. The amount of insoluble residue is usually higher in weathered carbonates and in some other cases in fresh carbonate, which is not very common but it may occur. Caves appear to be hosted within the claystone beds and concentrated within Injana Formation, whereas the Dibdibba Formation seems to form the roof of the caves. The mechanism of building caves starts by microdissolution forming microfractures. Then with time, they have developed to be vertical joints. These joints were gradually enlarged as a result of claystone exfoliation along joint planes. Chemical weathering, physical weathering, and sedimentary structure (mud balls) play a key role in the processes of cave evolution. Some caves appear to be irregular, but others tend to be regular with rectangular shape, enough for hosting human beings. These caves may have been used as homes for the ancient human for his protection and improvement of his life. At the same time as the caves were formed, there were other natural factors working continuously that destroy the cave. These factors are dissolution, soil creep, and mass sliding. This work highly recommends for further contributions in terms of the archaeological investigation on these caves to discover the ancient civilization in this area, if any. 相似文献
172.
Adnan Aslam Mubasher Jamil Davood Momeni Ratbay Myrzakulov Muneer Ahmad Rashid Muhammad Raza 《Astrophysics and Space Science》2013,348(2):533-540
In literature usual point like symmetries of the Lagrangian have been introduced to study the symmetries and the structure of the fields. This kind of Noether symmetry is a subclass of a more general family of symmetries, called Noether gauge symmetries (NGS). Motivated by this mathematical tool, in this paper, we study the generalized Noether symmetry of quintom model of dark energy, which is a two component fluid model with quintessence and phantom scalar fields. Our model is a generalization of the Noether symmetries of a single and multiple components which have been investigated in detail before. We found the general form of the quintom potential in which the whole dynamical system has a point like symmetry. We investigated different possible solutions of the system for diverse family of gauge function. Specially, we discovered two family of potentials, one corresponds to a free quintessence (phantom) and the second is in the form of quadratic interaction between two components. These two families of potential functions are proposed from the symmetry point of view, but in the quintom models they are used as phenomenological models without clear mathematical justification. From integrability point of view, we found two forms of the scale factor: one is power law and second is de-Sitter. Some cosmological implications of the solutions have been investigated. 相似文献
173.
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
174.
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
175.
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
176.
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
177.
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
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
178.
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
179.
180.
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