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土木環境工学ジャーナル

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音量 14, 問題 2 (2024)

研究論文

Groundwater Potential Zone Mapping of Lower Omo-Gibe Watershed, Omo-Gibe Basin, Ethiopia

Eyasu Tafese Mekuria*

The demand for an investigation of groundwater is occasionally increased by the ever-increasing population and abrupt climatic changes. Groundwater is currently the most important source of fresh water, and many researchers are attempting to cover all aspects of this resource in order to achieve sustainable development. This scientific and academic research and studies are attempting to present a multi-range of techniques and methods focusing on groundwater pollution, potentials, assessment, and prediction. To delineate Groundwater Potential (GWP) zones in the lower Omo-Gibe Watershed, Omo-Gibe Basin, Ethiopia, an integrated strategy of Remote Sensing (RS), Geographic Information Systems (GIS), and Multi-Criteria Decision Analysis (MCDA) using Analytical Hierarchical Process (AHP) was used. For this purpose, seven GWP influencing thematic layers comprising lineament density, slope, soil, drainage density, landuse landcover, geology, elevation and rainfall map were used. Scale values for the classes and thematic layers within them were determined using Satty's AHP and based on expert and literary judgment. The thematic layers have been integrated via their rates using weighted overlay spatial function tool of ArcGIS to provide GWP map. The distribution and extents of different potential groundwater zone are 158.05 km2 (21.59%), 35.92 km2 (4.91%), 214.77 km2 (29.34%), 220.59 km2 (30.13%), and 102.72 km2 (14.03%) for very good, good, moderate and fair zone respectively. The study's conclusions can be used to develop a groundwater action plan that will effectively protect the study area's considerable groundwater resources. With regard to the long-term availability of groundwater, this research will be very beneficial to water management.

研究論文

Comparative Study of First-Order Elastic and Second-Order Inelastic Analysis of Steel Structure

Shrikant S Ingale*, Dipak V Patil and Ajit M Kadam

As IS 800:1984 has changed recommend actions from working stress to limit state design in year 2007, this required change in analysis from elastic to inelastic. Present commercial software’s are not incorporating inelastic analysis i.e. plastic analysis. Hence the use of limit state design has been declined by structural designer. In this project study review of different methods of analysis of steel frame is made.

研究論文

Study on the Removal of High Nitrate-nitrogen Concentration from Pig Farm Wastewater by Heterotrophic and Sulphur Autotrophic Synergistic Denitrification Filter Process

Qing Zhang*

Following the anaerobic fermentation process in a lagoon, the effluent from pig wastewater exhibited elevated levels of total nitrogen and nitrate nitrogen. The utilization of simple sulphur-limestone autotrophic denitrification resulted in a sluggish reaction rate and relatively moderate removal load. To enhance the efficacy of the sulphur autotrophic denitrification process, a strategy was implemented involving the introduction of a limited quantity of corncobs as a slow-release carbon source. This addition was made to a sulphur-limestone autotrophic denitrification reactor that was being operated in a continuous and stable manner. Furthermore, the volume ratio of the corncobs added was progressively increased. This study examines the alterations in nitrate nitrogen, Chemical Oxygen Demand (COD), sulphate, and alkali consumption within the sulphur-limestone autotrophic denitrification reactor, both prior to and after to the introduction of corncobs. This study examines the operational efficiency and reaction mechanism of a sulfur-limestone autotrophic denitrification reactor that is enhanced by the utilization of corncobs as a slow-release carbon source. The findings of the study indicate that the inclusion of maize cob carbon source in the sulphur limestone autotrophic denitrification process resulted in an improved effectiveness in removing nitrate and nitrogen. Additionally, when considering the three different ratios of corn cob carbon source, the process exhibited a Chemical Oxygen Demand (COD) removal rate exceeding 42%. The observed trend in the consumption of alkalinity in both the pure sulphur limestone autotrophic denitrification process and the sulphur limestone autotrophic denitrification process augmented by the three types of corncob slow-release carbon sources indicated an increase with time. The concentration of nitrate-nitrogen in the influent water exhibited a negative correlation with the length of the reactor flow-through. The addition of a slow-release carbon source derived from corncob greatly enhanced the autotrophic denitrification and denitrification impact in the three reactors. Moreover, there was an observed increase in the trend of heterotrophic denitrification as the amount of carbon source added increased. The experiments investigating mixotrophic denitrification reaction observed a positive correlation between the content of corn cob and the relative abundance of microbial flora. Specifically, an increase in corn cob content led to an increase in the relative abundance of Proteobacteria at the phylum level. Additionally, the relative abundance of various other flora at the genus level also increased proportionally. The efficacy of the mixotrophic denitrification process surpassed that of the sulphur-limestone autotrophic denitrification method in the treatment of nitrate-nitrogen wastewater characterized by a high concentration of nitrate-nitrogen. The former exhibited a higher denitrification rate and resulted in lower levels of sulphate ions and alkalinity production.

研究論文

Assessing the Environmental Sustainability of Walled City, Lahore

Ahmed Usman

Adequate knowledge of environmental sustainability is essential to the success of its global efforts. Thus, a study was conducted to investigate into the level of awareness of environmental sustainability in a developed city of Lahore, Punjab province, Pakistan. Data for the investigation was generated through the survey questionnaires across randomly selected adult inhabitants. Of the entire questionnaire, respondents responded according to their perceptions. Descriptive and inferential statistical analyses were conducted. Descriptive analysis showed that most of the respondents had the knowledge of environmental sustainability. It is recommended that information on environmental sustainability should be made available and be widely disseminated, especially its impacts and that international communities in conjunction with the national government should take charge of the control and of the associated risks. Further investigation is required to assess the strategies for coping and adapting to the effects of environmental sustainability in the area being studied.

研究論文

Plastic Hinge Length Requirements in Reinforced Concrete Couple Shear Wall Buildings for Seismic Reinforcement Detailing

SK Amjad Hossain* and Bagchi Ashutosh

Proper reinforcement detailing in plastic hinge regions is one of the important measures that could help damage control of structural walls subjected to any severe earthquake event. Inelastic curvatures are commonly assumed to be uniform over a height called plastic hinge length. Non-linear dynamic analyses are performed on a set of coupled shear wall buildings of simple configurations for different heights. Inelastic curvatures are calculated on numerous heights of all the buildings and plotted along with the height of the buildings. Plastic hinge lengths are estimated with the yield curvatures from analytical results. It becomes a common practice to estimate the plastic hinge length equal to 0.5 to 1.0 times the wall length, which basically were developed from experimental studies on beam and column elements. As per the Canadian standards CSA A23.3-04, the requirements to calculate plastic hinge lengths are identical for both cantilever and coupled shear walls, i.e., 1.5 times the wall length in the direction under consideration. Results from the present study show that inelastic curvatures are not uniform over the plastic hinge length and the Canadian requirement as per CSA A23.3-04 to calculate plastic hinge length is unconservative for couple shear walls and more critical for slender coupled shear walls. And the plastic hinge length calculation as per Canadian code CSA A23.3-14 (clause 21.5.2.1.2) is over conservative for coupled shear wall buildings and much more over conservative for slender coupled shear walls. A comparison studies with different researchers and building codes are made. A new multiplication factor is proposed for the safe estimation of plastic hinge length for couple shear walls of medium and high rise reinforced concrete buildings. Results indicate that it needs to consider 2.0 times wall length instead of 1.5 times wall length in the direction under consideration for the safe estimation of coupled shear wall plastic hinge length calculations.

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