The origin and movement of groundwater are the fundamental questions that address both the temporal and spatial aspects of ground water run and water supply related issues in hydrological systems.As groundwater flows ...The origin and movement of groundwater are the fundamental questions that address both the temporal and spatial aspects of ground water run and water supply related issues in hydrological systems.As groundwater flows through an aquifer,its composition and temperature may variation dependent on the aquifer condition through which it flows.Thus,hydrologic investigations can also provide useful information about the subsurface geology of a region.But because such studies investigate processes that follow under the Earth's shallow,obtaining the information necessary to answer these questions is not continuously easy.Springs,which discharge groundwater table directly,afford to study subsurface hydrogeological processes.The present study of estimation of aquifer factors such as transmissivity(T)and storativity(S)are vital for the evaluation of groundwater resources.There are several methods to estimate the accurate aquifer parameters(i.e.hydrograph analysis,pumping test,etc.).In initial days,these parameters are projected either by means of in-situ test or execution test on aquifer well samples carried in the laboratory.The simultaneous information on the hydraulic behavior of the well(borehole)that provides on this method,the reservoir and the reservoir boundaries,are important for efficient aquifer and well data management and analysis.The most common in-situ test is pumping test performed on wells,which involves the measurement of the fall and increase of groundwater level with respect to time.The alteration in groundwater level(drawdown/recovery)is caused due to pumping of water from the well.Theis(1935)was first to propose method to evaluate aquifer parameters from the pumping test on a bore well in a confined aquifer.It is essential to know the transmissivity(T=Kb,where b is the aquifer thickness;pumping flow rate,Q=TW(dh/dl)flow through an aquifer)and storativity(confined aquifer:S=bS_s,unconfined:S=S_y),for the characterization of the aquifer parameters in an unknown area so as to predict the rate of drawdown of the groundwater table/potentiometric surface throughout the pumping test of an aquifer.The determination of aquifer's parameters is an important basis for groundwater resources evaluation,numerical simulation,development and protection as well as scientific management.For determining aquifer's parameters,pumping test is a main method.A case study shows that these techniques have been fast speed and high correctness.The results of parameter's determination are optimized so that it has important applied value for scientific research and geology engineering preparation.展开更多
Nanocrystalline titanium oxide thin films have been deposited by spin coating technique and then have been analyzed to test their application in NH3 gas-sensing technology. In particular, spectrophotometric and con-du...Nanocrystalline titanium oxide thin films have been deposited by spin coating technique and then have been analyzed to test their application in NH3 gas-sensing technology. In particular, spectrophotometric and con-ductivity measurements have been performed in order to determine the optical and electrical properties of titanium oxide thin films. The structure and the morphology of such material have been investigated by X ray diffraction, Scanning microscopy, high resolution electron microscopy and selected area electron diffrac-tion. The X-ray diffraction measurements confirmed that the films grown by this technique have good crys-talline tetragonal mixed anatase and rutile phase structure The HRTEM image of TiO2 thin film showed grains of about 50-60 nm in size with aggregation of 10-15 nm crystallites. Selected area electron diffraction pattern shows that the TiO2 films exhibited tetragonal structure. The surface morphology (SEM) of the TiO2 film showed that the nanoparticles are fine The optical band gap of TiO2 film is 3.26 eV. Gas sensing proper-ties showed that TiO2 films were sensitive as well as fast in responding to NH3. A high sensitivity for ammo-nia indicates that the TiO2 films are selective for this gas.展开更多
Nanocrystalline copper oxide (CuO) thin films were deposited onto glass substrates by a spin coating technique using an aqueous solution of copper acetate. These films were characterized for their structural, mor-phol...Nanocrystalline copper oxide (CuO) thin films were deposited onto glass substrates by a spin coating technique using an aqueous solution of copper acetate. These films were characterized for their structural, mor-phological, optoelectronic properties by means of X-ray diffraction (XRD) scanning electron microscopy (SEM), UVspectroscopy and four probe method. The CuO films are oriented along (1 1 1) plane with the monoclinic crystal structure. These films were utilized in H2S sensors. The dependence of the H2S response on the operating temperature, H2S concentration of CuO film (annealed at 700。C) was investigated. The CuO film showed selectivity for H2S. The maximum H2S response of 25.2 % for the CuO film at gas concentra-tion of 100 ppm at operating temperature 200oC was achieved.展开更多
文摘The origin and movement of groundwater are the fundamental questions that address both the temporal and spatial aspects of ground water run and water supply related issues in hydrological systems.As groundwater flows through an aquifer,its composition and temperature may variation dependent on the aquifer condition through which it flows.Thus,hydrologic investigations can also provide useful information about the subsurface geology of a region.But because such studies investigate processes that follow under the Earth's shallow,obtaining the information necessary to answer these questions is not continuously easy.Springs,which discharge groundwater table directly,afford to study subsurface hydrogeological processes.The present study of estimation of aquifer factors such as transmissivity(T)and storativity(S)are vital for the evaluation of groundwater resources.There are several methods to estimate the accurate aquifer parameters(i.e.hydrograph analysis,pumping test,etc.).In initial days,these parameters are projected either by means of in-situ test or execution test on aquifer well samples carried in the laboratory.The simultaneous information on the hydraulic behavior of the well(borehole)that provides on this method,the reservoir and the reservoir boundaries,are important for efficient aquifer and well data management and analysis.The most common in-situ test is pumping test performed on wells,which involves the measurement of the fall and increase of groundwater level with respect to time.The alteration in groundwater level(drawdown/recovery)is caused due to pumping of water from the well.Theis(1935)was first to propose method to evaluate aquifer parameters from the pumping test on a bore well in a confined aquifer.It is essential to know the transmissivity(T=Kb,where b is the aquifer thickness;pumping flow rate,Q=TW(dh/dl)flow through an aquifer)and storativity(confined aquifer:S=bS_s,unconfined:S=S_y),for the characterization of the aquifer parameters in an unknown area so as to predict the rate of drawdown of the groundwater table/potentiometric surface throughout the pumping test of an aquifer.The determination of aquifer's parameters is an important basis for groundwater resources evaluation,numerical simulation,development and protection as well as scientific management.For determining aquifer's parameters,pumping test is a main method.A case study shows that these techniques have been fast speed and high correctness.The results of parameter's determination are optimized so that it has important applied value for scientific research and geology engineering preparation.
文摘Nanocrystalline titanium oxide thin films have been deposited by spin coating technique and then have been analyzed to test their application in NH3 gas-sensing technology. In particular, spectrophotometric and con-ductivity measurements have been performed in order to determine the optical and electrical properties of titanium oxide thin films. The structure and the morphology of such material have been investigated by X ray diffraction, Scanning microscopy, high resolution electron microscopy and selected area electron diffrac-tion. The X-ray diffraction measurements confirmed that the films grown by this technique have good crys-talline tetragonal mixed anatase and rutile phase structure The HRTEM image of TiO2 thin film showed grains of about 50-60 nm in size with aggregation of 10-15 nm crystallites. Selected area electron diffraction pattern shows that the TiO2 films exhibited tetragonal structure. The surface morphology (SEM) of the TiO2 film showed that the nanoparticles are fine The optical band gap of TiO2 film is 3.26 eV. Gas sensing proper-ties showed that TiO2 films were sensitive as well as fast in responding to NH3. A high sensitivity for ammo-nia indicates that the TiO2 films are selective for this gas.
文摘Nanocrystalline copper oxide (CuO) thin films were deposited onto glass substrates by a spin coating technique using an aqueous solution of copper acetate. These films were characterized for their structural, mor-phological, optoelectronic properties by means of X-ray diffraction (XRD) scanning electron microscopy (SEM), UVspectroscopy and four probe method. The CuO films are oriented along (1 1 1) plane with the monoclinic crystal structure. These films were utilized in H2S sensors. The dependence of the H2S response on the operating temperature, H2S concentration of CuO film (annealed at 700。C) was investigated. The CuO film showed selectivity for H2S. The maximum H2S response of 25.2 % for the CuO film at gas concentra-tion of 100 ppm at operating temperature 200oC was achieved.
