Search results for: river sand

Authors: Maryam Sayadi, Rana Sedighpour, Hossein Rezaie

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In this study, in order to evaluate water quality of Gamasiab and Gharehsoo rivers located in Kermanshah province, the information of a 5-year statistical period during the years 2014-2018 was used. To evaluate the hydrochemistry of water, first the type and hydrogeochemical facies of river water were determined using Stiff and Piper diagrams. Then, based on Gibbs diagram and combination diagrams, the factors controlling the chemical parameters of the two rivers were identified. Saturation indices were used to predict the possibility of dissolution and deposition of some minerals. Then, in order to classify water in different sections, fourteen water quality indicators for different uses along with WHO standard were used. Finally, factor analysis was used to determine the processes affecting the hydrochemistry of the two rivers. The results of this study showed that in both rivers, the predominant type and facies are bicarbonate of calcite. Also, the main factor in changing the chemical quality of water in both Gamasiab and Gharehsoo rivers is the water-rock reaction. According to the results of factor analysis in both rivers, two factors have the greatest impact on water quality in the region. Among the parameters of Gamasiab river in the first factor, HCO3-, Na+ and Cl-, respectively, had the highest factor loads, and in the second factor, SO42- and Mg2+ were selected as the main parameters. The parameters Ca2+, Cl- and Na have the highest factor loads in the first factor and in the second factor Mg2+ and SO42- have the highest factor loads in Gharehsoo river. The dissolution of carbonate formations due to their abundance and expansion in the two basins has a more significant effect on changing water chemistry. It has saturated the water of rivers with aragonite, calcite and dolomite. Due to the low contribution of the second factor in changing the chemical parameters, the water of both rivers is saturated with respect to evaporative minerals such as gypsum, halite and anhydrite in all stations. Based on Schoeller diagrams, Wilcox and other quality indicators in these two sections, the amount of main physicochemical parameters are in the desired range for drinking and agriculture. The results of Langelier, Ryznar, Larson-Skold and Puckorius indices showed that water is corrosive in industry.

Keywords: factor analysis, hydrochemical, saturation index, surface water quality

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Authors: Davood Rajabi, Mojgan Yazdani

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Non-linear Muskingum model is an efficient method for flood routing, however, the efficiency of this method is influenced by three applied parameters. Therefore, efficiency assessment of Imperialist Competition Algorithm (ICA) to evaluate optimum parameters of non-linear Muskingum model was addressed through this study. In addition to ICA, Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) were also used aiming at an available criterion to verdict ICA. In this regard, ICA was applied for Wilson flood routing; then, routing of two flood events of DoAab Samsami River was investigated. In case of Wilson flood that the target function was considered as the sum of squared deviation (SSQ) of observed and calculated discharges. Routing two other floods, in addition to SSQ, another target function was also considered as the sum of absolute deviations of observed and calculated discharge. For the first floodwater based on SSQ, GA indicated the best performance, however, ICA was on first place, based on SAD. For the second floodwater, based on both target functions, ICA indicated a better operation. According to the obtained results, it can be said that ICA could be used as an appropriate method to evaluate the parameters of Muskingum non-linear model.

Keywords: Doab Samsami river, genetic algorithm, imperialist competition algorithm, meta-exploratory algorithms, particle swarm optimization, Wilson flood

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Authors: Zeina Bourhane, Anders Lanzen, Christine Cagnon, Olfa Ben Said, Cristiana Cravo-Laureau, Robert Duran

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The anthropogenic pressure in coastal areas increases dramatically with the exploitation of environmental resources. Biomonitoring coastal areas are crucial to determine the impact of pollutants on bacterial communities in soils and sediments since they provide important ecosystem services. However, relevant biomonitoring tools allowing fast determination of the ecological status are yet to be defined. Microbial ecology approaches provide useful information for developing such microbial monitoring tools reporting on the effect of environmental stressors. Chemical and microbial molecular approaches were combined in order to determine microbial bioindicators for assessing the ecological status of soil and river ecosystems around the Ichkeul Lake (Tunisia), an area highly impacted by human activities. Samples were collected along soil/river/lake continuums in three stations around the Ichkeul Lake influenced by different human activities at two seasons (summer and winter). Contaminant pressure indexes (PI), including PAHs (Polycyclic aromatic hydrocarbons), alkanes, and OCPs (Organochlorine pesticides) contents, showed significant differences in the contamination level between the stations with seasonal variation. Bacterial communities were characterized by 16S ribosomal RNAs (rRNA) gene metabarcoding. Although microgAMBI indexes, determined from the sequencing data, were in accordance with contaminant contents, they were not sufficient to fully explain the PI. Therefore, further microbial indicators are still to be defined. The comparison of bacterial communities revealed the specific microbial assemblage for soil, river, and lake sediments, which were significantly correlated with contaminant contents and PI. Such observation offers the possibility to define a relevant set of bioindicators for reporting the effects of human activities on the microbial community structure. Such bioindicators might constitute useful monitoring tools for the management of microbial communities in coastal areas.

Keywords: bacterial communities, biomonitoring, contamination, human impacts, microbial bioindicators

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Authors: Yanghui Xu, Qin Ou, Xintu Wang, Feng Hou, Peng Li, Jan Peter van der Hoek, Gang Liu

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The level and removal of microplastics (MPs) in wastewater treatment plants (WWTPs) has been well evaluated by the particle number, while the mass concentration of MPs and especially nanoplastics (NPs) remains unclear. In this study, microfiltration, ultrafiltration and hydrogen peroxide digestion were used to extract MPs and NPs with different size ranges (0.01−1, 1−50, and 50−1000 μm) across the whole treatment schemes in two WWTPs. By identifying specific pyrolysis products, pyrolysis gas chromatography−mass spectrometry were used to quantify their mass concentrations of selected six types of polymers (i.e., polymethyl methacrylate (PMMA), polypropylene (PP), polystyrene (PS), polyethylene (PE), polyethylene terephthalate (PET), and polyamide (PA)). The mass concentrations of total MPs and NPs decreased from 26.23 and 11.28 μg/L in the influent to 1.75 and 0.71 μg/L in the effluent, with removal rates of 93.3 and 93.7% in plants A and B, respectively. Among them, PP, PET and PE were the dominant polymer types in wastewater, while PMMA, PS and PA only accounted for a small part. The mass concentrations of NPs (0.01−1 μm) were much lower than those of MPs (>1 μm), accounting for 12.0−17.9 and 5.6− 19.5% of the total MPs and NPs, respectively. Notably, the removal efficiency differed with the polymer type and size range. The low-density MPs (e.g., PP and PE) had lower removal efficiency than high-density PET in both plants. Since particles with smaller size could pass the tertiary sand filter or membrane filter more easily, the removal efficiency of NPs was lower than that of MPs with larger particle size. Based on annual wastewater effluent discharge, it is estimated that about 0.321 and 0.052 tons of MPs and NPs were released into the river each year. Overall, this study investigated the mass concentration of MPs and NPs with a wide size range of 0.01−1000 μm in wastewater, which provided valuable information regarding the pollution level and distribution characteristics of MPs, especially NPs, in WWTPs. However, there are limitations and uncertainties in the current study, especially regarding the sample collection and MP/NP detection. The used plastic items (e.g., sampling buckets, ultrafiltration membranes, centrifugal tubes, and pipette tips) may introduce potential contamination. Additionally, the proposed method caused loss of MPs, especially NPs, which can lead to underestimation of MPs/NPs. Further studies are recommended to address these challenges about MPs/NPs in wastewater.

Keywords: microplastics, nanoplastics, mass concentration, WWTPs, Py-GC/MS

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Authors: Taha Anjamrooz, Sareh Rajabi, Hasan Mahmmud, Ghassan Abulebdeh

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Water availability, as well as water demand, are not uniformly distributed in time and space. Numerous extra-large water diversion projects are launched in Amazon to alleviate water scarcities. This research utilizes statistical analysis to examine the temporal and spatial features of 40 extra-large water diversion projects in Amazon. Using a network analysis method, the correlation between seven major basins is measured, while the impact analysis method is employed to explore the associated economic, environmental, and social impacts. The study unearths that the development of water diversion in Amazon has witnessed four stages, from a preliminary or initial period to a phase of rapid development. It is observed that the length of water diversion channels and the quantity of water transferred have amplified significantly in the past five decades. As of 2015, in Amazon, more than 75 billion m³ of water was transferred amidst 12,000 km long channels. These projects extend over half of the Amazon Area. The River Basin E is currently the most significant source of transferred water. Through inter-basin water diversions, Amazon gains the opportunity to enhance the Gross Domestic Product (GDP) by 5%. Nevertheless, the construction costs exceed 70 billion US dollars, which is higher than any other country. The average cost of transferred water per unit has amplified with time and scale but reduced from western to eastern Amazon. Additionally, annual total energy consumption for pumping exceeded 40 billion kilowatt-hours, while the associated greenhouse gas emissions are assessed to be 35 million tons. Noteworthy to comprehend that ecological problems initiated by water diversion influence the River Basin B and River Basin D. Due to water diversion, more than 350 thousand individuals have been relocated, away from their homes. In order to enhance water diversion sustainability, four categories of innovative measures are provided for decision-makers: development of water tradeoff projects strategies, improvement of integrated water resource management, the formation of water-saving inducements, and pricing approach, and application of ex-post assessment.

Keywords: sustainability, water trade-off projects, environment, Amazon

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Authors: Kanupreiya, Rajani Sharma

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Construction of a single underground structure is itself a challenging task, and it becomes more critical in tectonically active young mountains such as the Himalayas which are highly anisotropic. The Himalayan geology mostly comprises of incompetent and sheared rock mass in addition to fold/faults, rock burst, and water ingress. Underground tunnels form the most essential and important structure in run-of-river hydroelectric projects. Punatsangchhu I hydroelectric project (PHEP-I), Bhutan (1200 MW) is a run-of-river scheme which has four parallel underground desilting chambers. The Punatsangchhu River carries a large quantity of silt load during monsoon season. Desilting chambers were provided to remove the silt particles of size greater than and equal to 0.2 mm with 90% efficiency, thereby minimizing the rate of damage to turbines. These chambers are 330 m long, 18 m wide at the center and 23.87 m high, with a 5.87 m hopper portion. The geology of desilting chambers was known from an exploratory drift which exposed low dipping foliation joint and six joint sets. The RMR and Q value in this reach varied from 40 to 60 and 1 to 6 respectively. This paper describes different rock engineering principles undertaken for safe excavation and rock support of the moderately jointed, blocky and thinly foliated biotite gneiss. For the design of rock support system of desilting chambers, empirical and numerical analysis was adopted. Finite element analysis was carried out for cavern design and finalization of pillar width using Phase2. Phase2 is a powerful tool for simulation of stage-wise excavation with simultaneous provision of support system. As the geology of the region had 7 sets of joints, in addition to FEM based approach, safety factors for potentially unstable wedges were checked using UnWedge. The final support recommendations were based on continuous face mapping, numerical modelling, empirical calculations, and practical experiences.

Keywords: dam siltation, Himalayan geology, hydropower, rock support, numerical modelling

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Authors: Katarina Lazarević, Mirjana Todosijević, Tijana Vulević, Natalija Momirović, Ranka Erić

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Due to increasing demand, climate change, and world population growth, natural resources are getting exploit fast. One of the most important natural resources is soil, which is susceptible to degradation. Erosion as one of the forms of land degradation is also one of the most global environmental problems. Ecosystem services are often defined as benefits that nature provides to humankind. Soil, as the foundation of basic ecosystem functions, provides benefits to people, erosion control, water infiltration, food, fuel, fibers… This research is using the ecosystem approach as a strategy for natural resources management for promoting sustainability and conservation. The research was done on the Topčiderska River basin (Belgrade, Serbia). The InVEST Sediment Delivery Ratio model was used, to quantify erosion intensity with a spatial distribution output map of overland sediment generation and delivery to the stream. InVEST SDR, a spatially explicit model, is using a method based on the concept of hydrological connectivity and (R) USLE model. This, combined with socio-economic and law and policy analysis, gives a full set of information to decision-makers helping them to successfully manage and deliver sustainable ecosystems.

Keywords: ecosystem services, InVEST model, soil erosion, sustainability

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Authors: Arvind Kumar

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The city of Kanpur is located in the terrestrial plain area on the bank of the river Ganges and is the second largest city in the state of Uttar Pradesh. The city generates approximately 1400-1600 tons per day of MSW. Kanpur has been known as a major point and non-points-based pollution hotspot for the river Ganges. The city has a major industrial hub, probably the largest in the state, catering to the manufacturing and recycling of plastic and other dry waste streams. There are 4 to 5 major drains flowing across the city, which receive a significant quantity of waste leakage, which subsequently adds to the Ganges flow and is carried to the Bay of Bengal. A river-to-sea flow approach has been established to account for leaked waste into urban drains, leading to the build-up of marine litter. Throughout its journey, the river accumulates plastic – macro, meso, and micro, from various sources and transports it towards the sea. The Ganges network forms the second-largest plastic-polluting catchment in the world, with over 0.12 million tonnes of plastic discharged into marine ecosystems per year and is among 14 continental rivers into which over a quarter of global waste is discarded 3.150 Kilo tons of plastic waste is generated in Kanpur, out of which 10%-13% of plastic is leaked into the local drains and water flow systems. With the Support of Kanpur Municipal Corporation, 1TPD capacity MRF for drain waste management was established at Krishna Nagar, Kanpur & A German startup- Plastic Fisher, was identified for providing a solution to capture the drain waste and achieve its recycling in a sustainable manner with a circular economy approach. The team at Plastic Fisher conducted joint surveys and identified locations on 3 drains at Kanpur using GIS maps developed during the survey. It suggested putting floating 'Boom Barriers' across the drains with a low-cost material, which reduced their cost to only 2000 INR per barrier. The project was built upon the self-sustaining financial model. The project includes activities where a cost-efficient model is developed and adopted for a socially self-inclusive model. The project has recommended the use of low-cost floating boom barriers for capturing waste from drains. This involves a one-time time cost and has no operational cost. Manpower is engaged in fishing and capturing immobilized waste, whose salaries are paid by the Plastic Fisher. The captured material is sun-dried and transported to the designated place, where the shed and power connection, which act as MRF, are provided by the city Municipal corporation. Material aggregation, baling, and transportation costs to end-users are borne by Plastic Fisher as well.

Keywords: Kanpur, marine environment, drain waste management, plastic fisher

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Authors: Rezvan Khavari

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The Zagros fold-thrust belt in SW Iran is a part of the Alpine-Himalayan system which consists of a variety of structures with different sizes or geometries. The study area is Chamshir Dam, which is located on the Zohreh River, 20 km southeast of Gachsaran City (southwest Iran). The satellite images are valuable means available to geologists for locating geological or geomorphological features expressing regional fault or fracture systems, therefore, the satellite images were used for structural analysis of the Chamshir dam area. As well, using the DEM and geological maps, 3D Models of the area have been constructed. Then, based on these models, all the acquired fracture traces data were integrated in Geographic Information System (GIS) environment by using Arc GIS software. Based on field investigation and DEM model, main structures in the area consist of Cham Shir syncline and two fault sets, the main thrust faults with NW-SE direction and small normal faults in NE-SW direction. There are three joint sets in the study area, both of them (J1 and J3) are the main large fractures around the Chamshir dam. These fractures indeed consist with the normal faults in NE-SW direction. The third joint set in NW-SE is normal to the others. In general, according to topography, geomorphology and structural geology evidences, Chamshir dam has a potential for sliding in some parts of Gachsaran formation.

Keywords: DEM, chamshir dam, zohreh river, satellite images

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Authors: Renata Silva-Mann, Sheila Valéria Álvares Carvalho, Robério Anastácio Ferreira, Laura Jane Gomes

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There is growing interest in defining indicators of sustainability, which are important for monitoring the conservation of native forests, particularly in areas of permanent protection. These indicators are references for assessing the state of the forest and the status of the depredated area and its ability to maintain species populations. The aim of the present study was to select genetic parameters as indicators of sustainability for Schinus terebinthifolius Raddi. Fragments located in riparian areas between the Sergipe and Alagoas States in Brazil. This species has been exploited for traditional communities, which represent 20% of the incoming. This study was carried out using the indicators suggested by the Organization for Economic Cooperation and Development, which were identified as Driving-Pressure-State-Impact-Response (DPSIR) factors. The genetic parameters were obtained in five populations located on the shores and islands of the São Francisco River, one of the most important rivers in Brazil. The framework for Schinus conservation suggests seventeen indicators of sustainability. In accordance with genetic parameters, the populations are isolated, and these genetic parameters can be used to monitor the sustainability of those populations in riparian area with the aim of defining strategies for forest restoration.

Keywords: alleles, molecular markers, genetic diversity, biodiversity

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Authors: Olga A. Momot, Boris I. Synzynys, Alla A. Oudalova

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Obninsk is situated in the Kaluga region 100 km southwest of Moscow on the left bank of the Protva River. Several enterprises utilizing nuclear energy are operating in the town. A special attention in the region where radiation-hazardous facilities are located has traditionally been paid to radioactive gas and aerosol releases into the atmosphere; liquid waste discharges into the Protva river and groundwater pollution. Municipal intakes involve 34 wells arranged 15 km apart in a sequence north-south along the foot of the left slope of the Protva river valley. Northern and southern water intakes are upstream and downstream of the town, respectively. They belong to river valley intakes with mixed feeding, i.e. precipitation infiltration is responsible for a smaller part of groundwater, and a greater amount is being formed by overflowing from Protva. Water intakes are maintained by the Protva river runoff, the volume of which depends on the precipitation fallen out and watershed area. Groundwater contamination with tritium was first detected in a sanitary-protective zone of the Institute of Physics and Power Engineering (SRC-IPPE) by Roshydromet researchers when realizing the “Program of radiological monitoring in the territory of nuclear industry enterprises”. A comprehensive survey of the SRC-IPPE’s industrial site and adjacent territories has revealed that research nuclear reactors and accelerators where tritium targets are applied as well as radioactive waste storages could be considered as potential sources of technogenic tritium. All the above sources are located within the sanitary controlled area of intakes. Tritium activity in water of springs and wells near the SRC-IPPE is about 17.4 – 3200 Bq/l. The observed values of tritium activity are below the intervention levels (7600 Bq/l for inorganic compounds and 3300 Bq/l for organically bound tritium). The risk has being assessed to estimate possible effect of considered tritium concentrations on human health. Data on tritium concentrations in pipe-line drinking water were used for calculations. The activity of 3H amounted to 10.6 Bq/l and corresponded to the risk of such water consumption of ~ 3·10-7 year-1. The risk value given in magnitude is close to the individual annual death risk for population living near a NPP – 1.6·10-8 year-1 and at the same time corresponds to the level of tolerable risk (10-6) and falls within “risk optimization”, i.e. in the sphere for planning the economically sound measures on exposure risk reduction. To estimate the chemical risk, physical and chemical analysis was made of waters from all springs and wells near the SRC-IPPE. Chemical risk from groundwater contamination was estimated according to the EPA US guidance. The risk of carcinogenic diseases at a drinking water consumption amounts to 5·10-5. According to the classification accepted the health risk in case of spring water consumption is inadmissible. The compared assessments of risk associated with tritium exposure, on the one hand, and the dangerous chemical (e.g. heavy metals) contamination of Obninsk drinking water, on the other hand, have confirmed that just these chemical pollutants are responsible for health risk.

Keywords: radiation-hazardous facilities, water intakes, tritium, heavy metal, health risk

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Authors: Jawdhari Abdulhusein, Dan Mihăilescu, Cristian-Emilian Pop, Nicolai Crăciun

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Cyprinus Carpio adult specimens were captured from a single spot location from the Danube River and transported to the Laboratory of Faculty of Biology, University of Bucharest. The specimens were measured, weighed and randomly divided in five groups for later Copper Sulphate (CuSO4) exposure, as well as one control group. From the control group, 3 specimens were immediately sacrificed and microscopically inspected for parasite’s presence in the gills. During the histological inspection of the control group specimens, Ichthyophthiriusmultifiliis, Gyrodactylu ssp., MyxobolusOviforis, and Trichodinacottidarumwere abundantly identified in the gills. The exposure to a single dose of CuSO4 per group took place for 7 days under controlled conditions: water alkalinity ≈ 100 mg/L, temperature 23–24 °C, oxygenation 7.40–7.80 mg/L, and pH 6.10–6.40, the parameters were monitored on an hourly basis and adjusted when needed. After the exposure, all specimens were sacrificed, and the gill tissues were inspected. It was found that concentrations of 0.10, 0.25 and 0.30 ppm of CuSO4 did not affect the presence of parasites, as for 0.40 ppm of CuSO4 it significantly affected onlyIchthyophthiriusmultifiliisandMyxobolusOviforis, while concentration 0.50 ppm of CuSO4 (≈0.20 ppm of Cu2+) eliminated all 4 parasites species previously present in the fish gills, also, there were some histopathological changes to the gills tissue. These findings suggest that low concentrations of CuSO4 treatment for fish parasites are a safe and economical option if used correctly for a brief length of time.

Keywords: copper sulphate, cyprinus carpio, parasites, danube river

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Authors: Loonibha Manandhar, Rajendra Bhandari, Kumud Raj Kafle

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Nepal’s Terai region is a part of the Ganges river basin which is one of the most disaster-prone areas of the world, with recurrent monsoon flooding causing millions in damage and the death and displacement of hundreds of people and households every year. The vulnerability of human settlements to natural disasters such as floods is increasing, and mapping changes in land use practices and hydro-geological parameters is essential in developing resilient communities and strong disaster management policies. The objective of this study was to develop a flood hazard zonation map of Orai Khola watershed and map the decadal land use/land cover dynamics of the watershed. The watershed area was delineated using SRTM DEM, and LANDSAT images were classified into five land use classes (forest, grassland, sediment and bare land, settlement area and cropland, and water body) using pixel-based semi-automated supervised maximum likelihood classification. Decadal changes in each class were then quantified using spatial modelling. Flood hazard mapping was performed by assigning weights to factors slope, rainfall distribution, distance from the river and land use/land cover on the basis of their estimated influence in causing flood hazard and performing weighed overlay analysis to identify areas that are highly vulnerable. The forest and grassland coverage increased by 11.53 km² (3.8%) and 1.43 km² (0.47%) from 1996 to 2016. The sediment and bare land areas decreased by 12.45 km² (4.12%) from 1996 to 2016 whereas settlement and cropland areas showed a consistent increase to 14.22 km² (4.7%). Waterbody coverage also increased to 0.3 km² (0.09%) from 1996-2016. 1.27% (3.65 km²) of total watershed area was categorized into very low hazard zone, 20.94% (60.31 km²) area into low hazard zone, 37.59% (108.3 km²) area into moderate hazard zone, 29.25% (84.27 km²) area into high hazard zone and 31 villages which comprised 10.95% (31.55 km²) were categorized into high hazard zone area.

Keywords: flood hazard, land use/land cover, Orai river, supervised maximum likelihood classification, weighed overlay analysis

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Authors: Ahmad Al-Turki

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Composting is the suitable way of recycling organic waste for agricultural application and environment protection. In Saudi Arabia, several composting facilities are available and producing high quantity of composts. The aim of this study is to evaluate the physical characteristics of composts manufactured in Saudi Arabia and acquire a comprehensive image of its quality through the comparative with international standards of compost quality such as CCQC and PAS-100. In the present study different locally produced compost were identified and most of the producing factories were visited during the manufacturing of composts. Representative samples of different compost production stage were collected and Physical characteristics were determined, which included moisture content, bulk density, percentage of sand and the size of distribution of the compost particles. Results showed wide variations in all parameters investigated. Results of the study indicated generally that there is a wide variation in the physical characteristics of the types of compost under study. The initial moister contents in composts were generally low, it was less than 60% in most samples and not sufficient for microbial activities for biodegradation in 96% of the 96% of the types of compost and this will impede the decomposition of organic materials. The initial bulk density values ranged from 117 gL-1 to 1110.0 gL-1, while the final apparent bulk density ranged from 340.0 gL-1 to 1000gL-1 and about 45.4 % did not meet the ideal bulk density value. Sand percents in composts were between 3.3 % and 12.5%. This study has confirmed the need for a standard specification for compost manufactured in Saudi Arabia for agricultural use based on international standards for compost and soil characteristics and climatic conditions in Saudi Arabia.

Keywords: compost, maturity, Saudi Arabia, organic material

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Authors: Soumita Mitra, Santosh Kumar Sarkar

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Hooghly river estuary (HRE), situated at the north eastern part of Bay of Bengal has global significance due to its holiness. It is of immense importance to the local population as it gives perpetual water supply for various activities such as transportation, fishing, boating, bathing etc. to the local people who settled on both the banks of this estuary. This study was done to assess the dissolved and particulate trace metal in the estuary covering a stretch of about 175 Km. The water samples were collected from the surface (0-5 cm) along the salinity gradient and metal concentration were studied both in dissolved and particulate phase using Graphite Furnace Atomic Absorption Spectrophotometer (GF-AAS) along some physical characteristics such as water temperature, salinity, pH, turbidity and total dissolved solids. Although much significant spatial variation was noticed but little enrichment was found along the downstream of the estuary. The mean concentration of the metals in the dissolved and particulate phase followed the same trend and as follows: Fe>Mn>Cr>Zn>Cu>Ni>Pb. The concentration of the metals in the particulate phase were much greater than that in dissolved phase which was also depicted from the values of the partition coefficient (Kd)(ml mg-1). The Kdvalues ranged from 1.5x105 (in case of Pb) to 4.29x106 (in case of Cr). The high value of Kd for Cr denoted that the metal Cr is mostly bounded with the suspended particulate matter while the least value for Pb signified it presence more in dissolved phase. Moreover, the concentrations of all the studied metals in the dissolved phase were many folds higher than their respective permissible limits assested by WHO 2008, 2009 and 2011. On the other hand, according to Sediment Quality Guidelines (SQGs), Zn, Cu and Ni in the particulate phase lied between ERL and ERM values but Cr exceeded ERM values at all the stations confirming that the estuary is mostly contaminated with the particulate Cr and it might cause frequent adverse effects on the aquatic life. Multivariate statistics Cluster analysis was also performed which separated the stations according to the level of contamination from several point and nonpoint sources. Thus, it is found that the estuarine system is much polluted by the toxic metals and further investigation, toxicological studies should be implemented for full risk assessment of this system, better management and restoration of the water quality of this globally significant aquatic system.

Keywords: dissolved and particulate phase, Hooghly river estuary, partition coefficient, surface water, toxic metals

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Authors: Supattra Suanlim

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Nonthaburi province is one of the provinces in the central region of Thailand. There is the Chao Phraya River, which is a large and important river of Thailand passing through the province. With the way of life and social changes since the past. There is a digging canal called Lat canal or Om canal, communities along the canal have dense settlements. Important in life and culture. This research has 3 objectives as follows. 1.To explore cultural and ecotourism attractions in the Om Nont canal area. 2.To explore the facilities in the Om Nont canal tourist attraction. To suggest facilities for tourist attractions in the Om Nont canal, Nonthaburi, Thailand. This research is a qualitative research, using research methods by collecting data and surveying tourist attractions by water traffic. The results of the research can be concluded that There are 21 tourist attractions that have the potential to welcome tourists who want to travel cultural. 16 temples or places of worship, 2 government offices, 1 market, 2 landmarks. Each should be improved to increase the potential of the paths. There should be improvements in the road landscape that is a connection to water traffic. Districts should have signage and signage installation within tourist sites and have guidelines for architectural improvements. And the Nodes should improve the public space of the community. Such as the Nonthaburi pier area to have the idea of designing a tourist center Provide information in both Thai and English.

Keywords: Community, Cultural, Ecotourism, Facility

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Authors: Sikiru F. Oritola, Abd Latif Saleh, Abd Rahman Mohd Sam, Rozana Zakaria, Mushairry Mustaffar

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The strength of concrete varies with the types of material used; the material used within concrete can also result in different strength due to improper selection of the component. Each material brings a different aspect to the concrete. This work studied the effect of using Iron ore Tailings (IOTs) as partial replacement for sand on some properties of concrete using Fly ash Cement as the binder. The sieve analysis and some other basic properties of the materials used in producing concrete samples were first determined. Two brands of Fly ash Cement were studied. For each brand of Fly ash Cement, five different types of concrete samples denoted as HCT0, HCT10, HCT20, HCT30 and HCT40, for the first brand and PCT0, PCT10, PCT20, PCT30 and PCT40, for the second brand were produced. The percentage of Tailings as partial replacement for sand in the sample was varied from 0% to 40% at 10% interval. For each concrete sample, the average of three cubes, three cylinders and three prism specimen results was used for the determination of the compressive strength, splitting tensile strength and the flexural strength respectively. Water/cement ratio of 0.54 with fly-ash cement content of 463 Kg/m3 was used in preparing the fresh concrete. The slump values for the HCT brand concrete ranges from 152mm – 75mm while that of PCT brand ranges from 149mm to 70mm. The concrete sample PCT30 recorded the highest 28 days compressive strength of 28.12 N/mm2, the highest splitting tensile strength of 2.99 N/mm2 as well as the highest flexural strength of 4.99 N/mm2. The texture of the iron-ore tailings is rough and angular and was therefore able to improve the strength of the fly ash cement concrete. Also, due to the fineness of the IOTs more void in the concrete can be filled, but this reaches the optimum at 30% replacement level, hence the drop in strength at 40% replacement

Keywords: concrete strength, fine aggregate, fly ash cement, iron ore tailings

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Authors: Konstantinos Sotiriadis, Michael Tupý, Nikol Žižková, Vít Petránek

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The acid attack on cement mortars modified with rubber aggregates and EVA polymer binder was studied. Mortar specimens were prepared using a type CEM I 42.5 Portland cement and siliceous sand, as well as by substituting 25% of sand with shredded used automobile tires, and by adding EVA polymer in two percentages (5% and 10% of cement mass). Some specimens were only air cured, at laboratory conditions, and their compressive strength and water absorption were determined. The rest specimens were stored in acid solutions (HCl, H2SO4, HNO3) after 28 days of initial curing, and stored at laboratory temperature. Compressive strength tests, mass measurements and visual inspection took place for 28 days. Compressive strength and water absorption of the air-cured specimens were significantly decreased when rubber aggregates are used. The addition of EVA polymer further reduced water absorption, while had no important impact on strength. Compressive strength values were affected in a greater extent by hydrochloric acid solution, followed by sulfate and nitric acid solutions. The addition of EVA polymer decreased compressive strength loss for the specimens with rubber aggregates stored in hydrochloric and nitric acid solutions. The specimens without polymer binder showed similar mass loss, which was higher in sulfate acid solution followed by hydrochloric and nitric acid solutions. The use of EVA polymer delayed mass loss, while its content did not affect it significantly.

Keywords: acid attack, mortar, EVA polymer, rubber aggregates

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Authors: S. Benessam, T. H. Debieche, S. Amiour, A. Chine, S. Khelili

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Iron is naturally present in groundwater, it comes from the dissolution of the geological formations (clay, schist, mica-schist, gneiss…). Its chemical form and mobility in water are controlled mainly by two physicochemical parameters (Eh and pH). In order to determine its spatiotemporal evolution in groundwater, a two-monthly monitoring of the physicochemical parameters and major elements in the water of the alluvial sheet of Nil river (North-eastern Algerian) was carried out during the period from November 2013 to January 2015. The results show that iron is present in weak concentrations in the upstream part of the alluvial sheet and with raised concentrations, which can exceed the standard of potable drinking water (0.2 mg/L), in the central and downstream parts of the alluvial sheet. This variation of the concentrations is related to the important variation of Eh between the upstream part (200 mV) where the aquiver is unconfined (oxidizing medium) and the central and downstream parts (-100 mV) where the aquifer is confined (reducing medium). Iron in the oxidizing part is presented with the complexes form, where it precipitates or/and adsorbed by the geological formations. On the other hand in the reducing parts, it is released in water. In this study, one will discuss also the mobility and the chemical forms of iron according to the rains and pumping.

Keywords: groundwater, iron, mobility, speciation

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Authors: Emrah Yaliniz, Ali Kalkanli

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ZE41A magnesium alloy has been extensively used in aerospace industry, especially for use in rotorcraft transmission casings. Due to the improved mechanical properties, the latest generation of magnesium casting alloy EV31A-T6 (Elektron 21® specified in AMS 4429) is seen as a potential replacement for ZE41A in terms of strength. Therefore, the necessity of enhancement has been arisen for ZE41A in order to avoid fully replacement. The main element affecting the strength of ZE41A is Zirconium (Zr), which acts as a grain refiner. The specified range of Zr element for ZE41A alloy is between 0.4 wt % and 1.0 wt % (unless otherwise stated by weight percentage after this point) as stated in AMS 4439. This paper investigates the effects of Zr amount on tensile and metallurgical properties of ZE41A magnesium alloy. The Zr alloying amount for the research has been chosen as 0.5 % and 1 %, which are standard amounts in a commercial alloy (average of 0.4-0.6%) and maximum percent in the standard, separately. 1 % Zr amount has been achieved via Zirmax (66.7 Mg-33.3 Zr) master alloy addition. The ultimate tensile strength of ZE41A with 1% Zr has been increased up to about 220-225 MPa in comparison to 200 MPa given in AMS 4439. The reason for the increase in strength with the addition of Zirmax is based on the decrease in grain size, which was measured about 30 µm. Optical microscope, scanning electron microscopy (SEM) and X-ray Diffraction (XRD) were used to detect the change in the microstructural futures via alloying. The zirconium rich coring at the center of the grains was observed in addition to the grain boundary intermetallic phases and bulk Mg-rich matrix. The solidification characteristics were also identified by using the cooling curve obtained from the sand casting mold during cooling of the alloys.

Keywords: aerospace, grain refinement, magnesium, sand casting, ZE41A

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Authors: Virginia Venturini, Elisabet Walker, Aylen Carrasco-Millan

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Latin America stands at the front of climate change impacts, with forecasts projecting accelerated temperature and sea level rises compared to the global average. These changes are set to trigger a cascade of effects, including coastal retreat, intensified droughts in some nations, and heightened flood risks in others. In Argentina, wildfires historically affected forests, but since 2004, wetland fires have emerged as a pressing concern. By 2021, the wetlands of the Paraná River faced a dangerous situation. In fact, during the year 2021, a high-risk scenario was naturally formed in the wetlands of the Paraná River, in Argentina. Very low water levels in the rivers, and excessive standing dead plant material (fuel), triggered most of the fires recorded in the vast wetland region of the Paraná during 2020-2021. During 2008 fire events devastated nearly 15% of the Paraná Delta, and by late 2021 new fires burned more than 300,000 ha of these same wetlands. Therefore, the goal of this work is to explore remote sensing tools to monitor environmental conditions and the severity of prescribed burns in the Paraná River wetlands. Thus, two prescribed burning experiments were carried out in the study area (31°40’ 05’’ S, 60° 34’ 40’’ W) during September 2023. The first experiment was carried out on Sept. 13th, in a plot of 0.5 ha which dominant vegetation were Echinochloa sp., and Thalia, while the second trial was done on Sept 29th in a plot of 0.7 ha, next to the first burned parcel; here the dominant vegetation species were Echinochloa sp. and Solanum glaucophyllum. Field campaigns were conducted between September 8th and November 8th to assess the severity of the prescribed burns. Flight surveys were conducted utilizing a DJI® Inspire II drone equipped with a Sentera® NDVI camera. Then, burn severity was quantified by analyzing images captured by the Sentera camera along with data from the Sentinel 2 satellite mission. This involved subtracting the NDVI images obtained before and after the burn experiments. The results from both data sources demonstrate a highly heterogeneous impact of fire within the patch. Mean severity values obtained with drone NDVI images of the first experience were about 0.16 and 0.18 with Sentinel images. For the second experiment, mean values obtained with the drone were approximately 0.17 and 0.16 with Sentinel images. Thus, most of the pixels showed low fire severity and only a few pixels presented moderated burn severity, based on the wildfire scale. The undisturbed plots maintained consistent mean NDVI values throughout the experiments. Moreover, the severity assessment of each experiment revealed that the vegetation was not completely dry, despite experiencing extreme drought conditions.

Keywords: prescribed-burn, severity, NDVI, wetlands

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Authors: Ameer A. Jebur, William Atherton, Rafid M. Alkhaddar, Edward Loffill

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Understanding the behaviour of the piles under the action of the independent lateral loads and the precise prediction of the capacity of piles subjected to different lateral loads are vital topics in foundation design and analysis. Moreover, the laterally loaded behaviour of deep foundations penetrated in cohesive and non-cohesive soils is basically analysed by the Winkler Model (beam on elastic foundation), in which the interaction between the pile embedded depth and contacted soil is simulated by nonlinear p–y curves. The presence of many approaches to interpret the behaviour of soil-pile interaction has resulted in numerous outputs and indicates that no general approach has yet been adopted. The current study presents the result of numerical modelling of the behaviour of steel tubular piles (25.4mm) outside diameter with various embedment depth-to-diameter ratios (L/d) embedded in a sand calibrated chamber of known relative density. The study revealed that the shear strength parameters of the sand specimens and the (L/d) ratios are the most significant factor influencing the response of the pile and its capacity while taking into consideration the complex interaction between the pile and soil. Good agreement has been achieved when comparing the application of this modelling approach with experimental physical modelling carried out by another researcher.

Keywords: deep foundations, slenderness ratio, soil-pile interaction, winkler model (beam on elastic foundation), non-cohesive soil

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Authors: Issamaldin Mohammed, Ahmed Abdalla, Hatim Elobied

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Soil erosion is globally known for adverse effects on social, environmental and economical aspects which directly or indirectly influence the human life. The area under study suffers from problems like water quality, river and agricultural canals bed rise due to high sediment load brought by Algash River from upstream (Eritrea high land), the current study utilized from remote sensing and Geographical Information System (GIS) to estimate the annual soil loss using Universal Soil Loss Equation (USLE). The USLE is widely used over the world which basically relies on rainfall erosivity factor (R), soil erodibility factor (K), topographic factor (LS), cover management factor (C) and support practice factor (P). The result of the study showed high soil loss in the study area, this result was illustrated in a form of map presenting the spatial distribution of soil loss amounts which classified into seven zones ranging from very slight zone (less than 2 ton/ha.year) to very severe (100-500 ton/ha.year), also the total soil loss from the whole study area was found to be 32,916,840.87 ton/ha.year. These kinds of results will help the experts of land management to give a priority for the severely affected zones to be tackled in an appropriate way.

Keywords: Geographical Information System, remote sensing, sedimentation, soil loss

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Authors: Shahryar Aftabi, Saeed Fathi, Mohammad H. Aminfar

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It is well known that cemented sand is one of the best approaches for soil stabilization. In some cases, a blend of sand, cement and other pozzolan materials such as zeolite, nano-particles and fiber can be widely (commercially) available and be effectively used in soil stabilization, especially in road construction. In this research, we investigate the effects of CaO which is based on the geotechnical characteristics of zeolite composition with sandy silt soil. Zeolites have low amount of CaO in their structures, that is, varying from 3% to 10%, and by removing the cement paste, we want to investigate the effect of zeolite pozzolan without any activator on soil samples strength. In this research, experiments are concentrated on various weight percentages of zeolite in the soil to examine the effect of the zeolite on drainage shear strength and California Bearing Ratio (CBR) both with and without curing. The study also investigates their liquid limit and plastic limit behavior and makes a comparative result by using Feng's and Wroth-Wood's methods in fall cone (cone penetrometer) device; in the final the SEM images have been presented. The results show that by increasing the percentage of zeolite in without-curing samples, the fine zeolite particles increase some soil's strength, but in the curing-state we can see a relatively higher strength toward without-curing state, since the zeolites have no plastic behavior, the pozzolanic property of zeolites plays a much higher role than cementing properties. Indeed, it is better to combine zeolite particle with activator material such as cement or lime to gain better results.

Keywords: California bearing ratio, CBR, direct shear, fall-cone, sandy silt, SEM, zeolite

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Authors: Younes Abed

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The successful application of in-situ testing of soils heavily depends on development of interpretation methods of tests. The pressuremeter test simulates the expansion of a cylindrical cavity and because it has well defined boundary conditions, it is more unable to rigorous theoretical analysis (i. e. cavity expansion theory) then most other in-situ tests. In this article, and in order to make the identification process more convenient, we propose a relatively simple procedure which involves the numerical identification of some mechanical parameters of a granular soil, especially, the elastic modulus and the friction angle from a pressuremeter curve. The procedure, applied here to identify the parameters of generalised prager model associated to the Drucker & Prager criterion from a pressuremeter curve, is based on an inverse analysis approach, which consists of minimizing the function representing the difference between the experimental curve and the curve obtained by integrating the model along the loading path in in-situ testing. The numerical process implemented here is based on the established finite element program. We present a validation of the proposed approach by a database of tests on expansion of cylindrical cavity. This database consists of four types of tests; thick cylinder tests carried out on the Hostun RF sand, pressuremeter tests carried out on the Hostun sand, in-situ pressuremeter tests carried out at the site of Fos with marine self-boring pressuremeter and in-situ pressuremeter tests realized on the site of Labenne with Menard pressuremeter.

Keywords: granular soils, cavity expansion, pressuremeter test, finite element method, identification procedure

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Authors: Agatha Padma Laksitaningtyas, Sumiyati Gunawan

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Mataram Irrigation Canal has 31,2 km length, is the main irrigation canal in Special Region Province of Yogyakarta, connecting Progo River on the west side and Opak River on the east side. It has an important role as the main water carrier distribution for various purposes such as agriculture, fishery, and plantation which should be free from sediment material. Bed Load Sediment is the basic sediment that will make the sediment process on the irrigation canal. Sediment process is a simultaneous event that can make deposition sediment at the base of irrigation canal and can make the height of elevation water change, it will affect the availability of water to be used for irrigation functions. To predict the amount of drowning sediments in the irrigation canal using two methods: Meyer-Peter and Muller’s Method which is an energy approach method and Einstein Method which is a probabilistic approach. Speed measurement using floating method and using current meters. The channel geometry is measured directly in the field. The basic sediment of the channel is taken in the field by taking three samples from three different points. The result of the research shows that by using the formula Meyer -Peter Muller get the result of 60,75799 kg/s, whereas with Einsten’s Method get result of 13,06461 kg/s. the results may serve as a reference for dredging the sediments on the channel so as not to disrupt the flow of water in irrigation canal.

Keywords: bed load, sediment, irrigation, Mataram canal

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Authors: Carla Idely Palencia-Aguilar

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Mining in Colombia represents around 2% of the GDP (USD 8 billion in 2018), with main productions represented by coal, nickel, gold, silver, emeralds, iron, limestone, gypsum, among others. Sand and Gravel had been decreasing its participation of the GDP with a reduction of 33.2 million m3 in 2015, to 27.4 in 2016, 22.7 in 2017 and 15.8 in 2018, with a consumption of approximately 3 tons/inhabitant. However, with the new government policies it is expected to increase in the following years. Mining causes temporary environmental impacts, once restoration and rehabilitation takes place, social, environmental and economic benefits are higher than the initial state. A way to demonstrate how the mining interventions had contributed to improve the characteristics of the region after sand and gravel mining, the NDVI (Normalized Difference Vegetation Index) from MODIS and ASTER were employed. The histograms show not only increments of vegetation in the area (8 times higher), but also topographies similar to the ones before the intervention, according to the application for sustainable development selected: either agriculture, forestry, cattle raising, artificial wetlands or do nothing. The decision was based upon a Multicriteria analysis for optimal land use, with three main variables: geostatistics, evapotranspiration and groundwater characteristics. The use of remote sensing, meteorological stations, piezometers, sunphotometers, geoelectric analysis among others; provide the information required for the multicriteria decision. For cattle raising and agricultural applications (where various crops were implemented), conservation of products were tested by means of nanotechnology. The results showed a duration of 2 years with no chemicals added for preservation and concentration of vitamins of the tested products.

Keywords: ASTER, Geostatistics, MODIS, Multicriteria

Procedia PDF Downloads 126

Authors: Nokwethaba Makhanya, Babatunde J. Abiodun, Piotr Wolski

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Climate change possibly intensifies hydrological droughts and reduces water availability in river basins. Despite this, most research on climate change effects in southern Africa has focused exclusively on meteorological droughts. This thesis projects the potential impact of climate change on the future characteristics of hydrological droughts in the Limpopo River Basin (LRB). The study uses regional climate model (RCM) measurements (from the Coordinated Regional Climate Downscaling Experiment, CORDEX) and a combination of hydrological simulations (using the Soil and Water Assessment Tool Plus model, SWAT+) to predict the impacts at four global warming levels (GWLs: 1.5℃, 2.0℃, 2.5℃, and 3.0℃) under the RCP8.5 future climate scenario. The SWAT+ model was calibrated and validated with a streamflow dataset observed over the basin, and the sensitivity of model parameters was investigated. The performance of the SWAT+LRB model was verified using the Nash-Sutcliffe efficiency (NSE), Percent Bias (PBIAS), Root Mean Square Error (RMSE), and coefficient of determination (R²). The Standardized Precipitation Evapotranspiration Index (SPEI) and the Standardized Precipitation Index (SPI) have been used to detect meteorological droughts. The Soil Water Index (SSI) has been used to define agricultural drought, while the Water Yield Drought Index (WYLDI), the Surface Run-off Index (SRI), and the Streamflow Index (SFI) have been used to characterise hydrological drought. The performance of the SWAT+ model simulations over LRB is sensitive to the parameters CN2 (initial SCS runoff curve number for moisture condition II) and ESCO (soil evaporation compensation factor). The best simulation generally performed better during the calibration period than the validation period. In calibration and validation periods, NSE is ≤ 0.8, while PBIAS is ≥ ﹣80.3%, RMSE ≥ 11.2 m³/s, and R² ≤ 0.9. The simulations project a future increase in temperature and potential evapotranspiration over the basin, but they do not project a significant future trend in precipitation and hydrological variables. However, the spatial distribution of precipitation reveals a projected increase in precipitation in the southern part of the basin and a decline in the northern part of the basin, with the region of reduced precipitation projected to increase with GWLs. A decrease in all hydrological variables is projected over most parts of the basin, especially over the eastern part of the basin. The simulations predict meteorological droughts (i.e., SPEI and SPI), agricultural droughts (i.e., SSI), and hydrological droughts (i.e., WYLDI, SRI) would become more intense and severe across the basin. SPEI-drought has a greater magnitude of increase than SPI-drought, and agricultural and hydrological droughts have a magnitude of increase between the two. As a result, this research suggests that future hydrological droughts over the LRB could be more severe than the SPI-drought projection predicts but less severe than the SPEI-drought projection. This research can be used to mitigate the effects of potential climate change on basin hydrological drought.

Keywords: climate change, CORDEX, drought, hydrological modelling, Limpopo River Basin

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Authors: Efil Yusrianto, Noraini Marsi, Noraniah Kassim, Izzati Abdul Manaf, Hafizuddin Hakim Shariff

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Today, municipal solid waste (MSW), noise pollution, and attack fire are three ongoing issues for inhabitants of urban including in Malaysia. To solve these issues, eco-friendly autoclaved aerated concrete (AAC) containing recycled ceramic and gypsum waste (CGW) as a partial replacement for sand with different ratios (0%, 5%, 10%, 15%, 20%, and 25% wt) has been prepared. The performance of samples, such as the physical, mechanical, sound absorption coefficient, and direct fire resistance, has been investigated. All samples showed normal color behavior, i.e., grey and free crack. The compressive strength was increased in the range of 6.10% to 29.88%. The maximum value of compressive strength was 2.13MPa for 15% wt of CGW. The positive effect of CGW on the compressive strength of AAC has also been confirmed by crystalline phase and microstructure analysis. The acoustic performances, such as sound absorption coefficients of samples at low frequencies (500Hz), are higher than the reference sample (RS). AAC-CGW samples are categorized as AAC material classes B and C. The fire resistance results showed the physical surface of the samples had a free crack and was not burned during the direct fire at 950ºC for 300s. The results showed that CGW succeeded in enhancing the performance of fresh AAC, such as compressive strength, crystalline phase, sound absorption coefficient, and fire resistance of samples.

Keywords: physical, mechanical, acoustic, direct fire resistance performance, autoclaved aerated concrete, recycled ceramic-gypsum waste

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Authors: Anjali Uday, Yuting Wang, Andres Alfonso Pena Olare

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The Discrete Element Method is a promising approach to modeling microscopic behaviors of granular materials. The quality of the simulations however depends on the model parameters utilized. The present study focuses on calibration and validation of the discrete element parameters for Cuxhaven sand based on the experimental data from triaxial and oedometer tests. A sensitivity analysis was conducted during the sample preparation stage and the shear stage of the triaxial tests. The influence of parameters like rolling resistance, inter-particle friction coefficient, confining pressure and effective modulus were investigated on the void ratio of the sample generated. During the shear stage, the effect of parameters like inter-particle friction coefficient, effective modulus, rolling resistance friction coefficient and normal-to-shear stiffness ratio are examined. The calibration of the parameters is carried out such that the simulations reproduce the macro mechanical characteristics like dilation angle, peak stress, and stiffness. The above-mentioned calibrated parameters are then validated by simulating an oedometer test on the sand. The oedometer test results are in good agreement with experiments, which proves the suitability of the calibrated parameters. In the next step, the calibrated and validated model parameters are applied to forecast the micromechanical behavior including the evolution of contact force chains, buckling of columns of particles, observation of non-coaxiality, and sample inhomogeneity during a simple shear test. The evolution of contact force chains vividly shows the distribution, and alignment of strong contact forces. The changes in coordination number are in good agreement with the volumetric strain exhibited during the simple shear test. The vertical inhomogeneity of void ratios is documented throughout the shearing phase, which shows looser structures in the top and bottom layers. Buckling of columns is not observed due to the small rolling resistance coefficient adopted for simulations. The non-coaxiality of principal stress and strain rate is also well captured. Thus the micromechanical behaviors are well described using the calibrated and validated material parameters.

Keywords: discrete element model, parameter calibration, triaxial test, oedometer test, simple shear test

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