Search results for: river sand

Authors: Ainas Belkacem, Fourar Ali

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The present study focuses on the mathematical modeling and calculation of physical parameters of water pollution by oil and sand in regime fully dispersed in water. In this study, the sand particles and oil are suspended in the case of fully developed turbulence. The study consists to understand, model and predict the viscosity, the structure and dynamics of these types of mixtures. The work carried out is Numerical and validated by experience.

Keywords: multi phase flow, pollution, suspensions, turbulence

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Authors: M. Abdullah Al Faruque, Ram Balachandar

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An experimental study with four different types of bed conditions was carried out to understand the effect of roughness in open channel flow at two different Reynolds numbers. The bed conditions include a smooth surface and three different roughness conditions which were generated using sand grains with a median diameter of 2.46 mm. The three rough conditions include a surface with distributed roughness, a surface with continuously distributed roughness and a sand bed with a permeable interface. A commercial two-component fibre-optic LDA system was used to conduct the velocity measurements. The variables of interest include the mean velocity, turbulence intensity, the correlation between the streamwise and the wall normal turbulence, Reynolds shear stress and velocity triple products. Quadrant decomposition was used to extract the magnitude of the Reynolds shear stress of the turbulent bursting events. The effect of roughness was evident throughout the flow depth. The results show that distributed roughness has the greatest roughness effect followed by the sand bed and the continuous roughness. Compared to the smooth bed, the streamwise turbulence intensity reduces but the vertical turbulence intensity increases at a location very close to the bed due to the introduction of roughness. Although the same sand grain is used to create the three different rough bed conditions, the difference in the turbulence intensity is an indication that the specific geometry of the roughness has an influence on turbulence structure.

Keywords: open channel flow, smooth and rough bed, Reynolds number, turbulence

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Authors: Nadjiba Mahfoudi, Abdelhafid Moummi , Mohammed El Ganaoui

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Thermal applications are drawing increasing attention in the solar energy research field, due to their high performance in energy storage density and energy conversion efficiency. In these applications, solar collectors and thermal energy storage systems are the two core components. This paper presents a thermal analysis of the transient behavior and storage capability of a sensible heat storage device in which sand is used as a storage media. The TES unit with embedded charging tubes is connected to a solar air collector. To investigate it storage characteristics a 3D-model using no linear coupled partial differential equations for both temperature of storage medium and heat transfer fluid (HTF), has been developed. Performances of thermal storage bed of capacity of 17 MJ (including bed temperature, charging time, energy storage rate, charging energy efficiency) have been evaluated. The effect of the number of charging tubes (3 configurations) is presented.

Keywords: design, thermal modeling, heat transfer enhancement, sand, sensible heat storage

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Authors: Ali Mohammadi

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The construction of Embankment dams is considered one of the most challenging construction projects, for which several main reasons can be mentioned. Excavation and embankment must be done in a large area, and its design is based on preliminary studies, but at the time of construction, it is possible that excavation does not match with the stability or slope of the rock, or the design is incomplete, and corrections should be made in order to be able to carry out excavation and embankment. Also, the progress of the work depends on the main factors, the lack of each of which can slow down the construction of the dams, and lead to an increase in costs, and control of excavations and embankments and calculations of their volumes are done in this collection. In the following, we will investigate three Embankment dams in Iran that faced these challenges and how they overcame these challenges. KHODA AFARIN on the Aras River between the two countries of IRAN and AZARBAIJAN, SIAH BISHEH PUMPED STORAGE on CHALUS River and GOTVAND on KARUN River are among the most important dams built in Iran.

Keywords: section, data transfer, tunnel, free station

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Authors: Sharifullah Ahmed, Sarwar Jahan Md. Yasin

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Shallow foundations on unimproved soft natural soils can undergo a high consolidation and secondary settlement. For low and medium rise building projects on such soil condition, pile foundation may not be cost effective. In such cases an alternative to pile foundations may be shallow strip footings placed on a double layered improved soil system soil. The upper layer of this system is untreated or cement treated compacted sand and underlying layer is natural soft clay. This system will reduce the settlement to an allowable limit. The current research has been conducted with the settlement of a rigid plane-strain strip footing of 2.5 m width placed on the surface of a soil consisting of an untreated or cement treated sand layer overlying a bed of homogeneous soft clay. The settlement of the mentioned shallow foundation has been studied considering both cases with the thicknesses of the sand layer are 0.3 to 0.9 times the width of footing. The response of the clay layer is assumed as undrained for plastic loading stages and drained during consolidation stages. The response of the sand layer is drained during all loading stages. FEM analysis was done using PLAXIS 2D Version 8.0. A natural clay deposit of 15 m thickness and 18 m width has been modeled using Hardening Soil Model, Soft Soil Model, Soft Soil Creep Model, and upper improvement layer has been modeled using only Hardening Soil Model. The groundwater level is at the top level of the clay deposit that made the system fully saturated. Parametric study has been conducted to determine the effect of thickness, density, cementation of the sand mat and density, shear strength of the soft clay layer on the settlement of strip foundation under the uniformly distributed vertical load of varying value. A set of the chart has been established for designing shallow strip footing on the sand mat over thick, soft clay deposit through obtaining the particular thickness of sand mat for particular subsoil parameter to ensure no punching shear failure and no settlement beyond allowable level. Design guideline in the form of non-dimensional charts has been developed for footing pressure equivalent to medium-rise residential or commercial building foundation with strip footing on soft inorganic Normally Consolidated (NC) soil of Bangladesh having void ratio from 1.0 to 1.45.

Keywords: design charts, ground improvement, PLAXIS 2D, primary and secondary settlement, sand mat, soft clay

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Authors: Manjie Li, Xiangju Cheng, Yongcan Chen

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With rapid development of industrialization and urbanization, water environmental deterioration is widespread in majority of urban rivers, which seriously affects city image and life satisfaction of residents. As an emergency measure to improve water quality, clean water diversion is introduced for water environmental management. Lubao River and Southwest River, two urban rivers in typical plain tidal river network, are identified as technically and economically feasible for the application of clean water diversion. One-dimensional hydrodynamic-water quality model is developed to simulate temporal and spatial variations of water level and water quality, with satisfactory accuracy. The mathematical model after calibration is applied to investigate hydrodynamic and water quality variations in rivers as well as determine the optimum operation scheme of water diversion. Assessment system is developed for evaluation of positive and negative effects of water diversion, demonstrating the effectiveness of clean water diversion and the necessity of pollution reduction.

Keywords: assessment system, clean water diversion, hydrodynamic-water quality model, tidal river network, urban rivers, water environment improvement

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Authors: Luthfi Assholam Solamat

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Nowadays many people do not know the soil failure pattern as an important part in planning the under structure caused by the loading occurs. This is because the soil is located under the foundation, so it cannot be seen directly. Based on this study, the idea occurs to do a study for testing the soil failure pattern, especially the type of sand soil under the foundation. The necessity of doing this to the design of building structures on the land which is the initial part of the foundation structure that met with waves/vibrations during an earthquake. If the underground structure is not strong it is feared the building thereon more vulnerable to the risk of building damage. This research focuses on the search of soil failure pattern, which the most applicable in the field with the loading periodic re-testing of a particular time with the help of the integrated video visual observations performed. The results could be useful for planning under the structure in an effort to try the upper structure is minimal risk of the earthquake.

Keywords: soil failure pattern, earthquake, under structure, sand soil testing method

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Authors: J. Omer, H. Haroglu

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Base enlargement in piles was invented to enhance pile resistance in downward loading, but the contribution of an enlarged base to the lateral load resistance of a pile has not been fully exploited or understood. This paper presents a laboratory investigation of the lateral capacity and deformation response of small-scale steel piles with enlarged bases installed in dry sand. Static loading tests were performed on 24 model piles having different base-to-shaft diameter ratios. The piles were installed in a box filled with dry sand, and lateral loads were applied to the pile tops using a pulley system. The test piles had shaft diameters of 20 mm, 16 mm, and 10 mm; base diameters of 900 mm, 700 mm, and 500 mm. As a control, a pile without base enlargement was tested to allow comparisons with the enlarged base piles. Incremental maintained loads were applied until pile failure approached while recording pile head deflections with high-precision dial gauges. The results showed that the lateral capacity increased with an increase in base diameter, albeit by different percentages depending on the shaft diameters and embedment length in the sand. There was always an increase in lateral capacity with increasing embedment length. Also, it was observed that an enlarged pile base had deflected less at a given load when compared to the control pile. Therefore, the research demonstrated the benefits of lateral capacity and stability of enlarging a pile base.

Keywords: pile foundations, enlarged base, lateral loading

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Authors: M. A. At-Tasneem, N. T. Rao, T. M. Y. S. Tuan Ya, M. S. Idris, M. Ammar

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River flow over micro hydro power (MHP) turbines of multiple arrays arrangement is simulated with computational fluid dynamics (CFD) software to obtain the flow characteristics. In this paper, CFD software is used to simulate the water flow over MHP turbines as they are placed in a river. Multiple arrays arrangement of MHP turbines lead to generate large amount of power. In this study, a river model is created and simulated in CFD software to obtain the water flow characteristic. The process then continued by simulating different types of arrays arrangement in the river model. A MHP turbine model consists of a turbine outer body and static propeller blade in it. Five types of arrangements are used which are parallel, series, triangular, square and rhombus with different spacing sizes. The velocity profiles on each MHP turbines are identified at the mouth of each turbine bodies. This study is required to obtain the arrangement with increasing spacing sizes that can produce highest power density through the water flow variation.

Keywords: micro hydro power, CFD, arrays arrangement, spacing sizes, velocity profile, power

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Authors: Dhyaalddin Bahaalddin Noori Zangana

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This study involves the behavior of reinforced sand under a square footing. A series of bearing capacity tests were performed on a small-scale laboratory model, which filled with a poorly-graded homogenous bed of sand, which was placed in a medium dense state using sand raining technique. The sand was reinforced with 40 mm wide household aluminum foil strips. The main studied parameters was to consider the effect of reinforcing strip length, with various linear density of reinforcement, number of reinforcement layers and depth of top layer of reinforcement below the footing, on load-settlement behavior, bearing capacity ratio and settlement reduction factor. The relation of load-settlement generally showed similar trend in all the tests. Failure was defined as settlement equal to 10% of the footing width. The recommended optimum reinforcing strip length, linear density of reinforcement, number of reinforcement layers and depth of top layer of reinforcing strips that give the maximum bearing capacity improvement and minimum settlement reduction factor were presented and discussed. Different bearing capacity ration versus length of the reinforcing strips and settlement reduction factor versus length of the reinforcing strips relations at failure were showed improvement of bearing capacity ratio by a factor of 3.82 and reduction of settlement reduction factor by a factor of 0.813. The optimum length of reinforcement was found to be 7.5 times the footing width.

Keywords: square footing, relative density, linear density of reinforcement, bearing capacity ratio, load-settlement behaviour

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Authors: Jin-Hong Kim

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Hydraulic analysis on microhabitat of Benthic Macro- invertebrates was performed at riparian riffles of Hongcheon River and Gapyeong Stream. As for the representative species, Ecdyonurus kibunensis, Paraleptophlebia cocorata, Chironomidae sp. and Psilotreta kisoensis iwata were chosen. They showed hydraulically different habitat types by flow velocity and particle diameters of streambed materials. Habitat conditions of the swimmers were determined mainly by the flow velocity rather than by flow depth or by riverbed materials. Burrowers prefer sand and silt, and inhabited at the riverbed. Sprawlers prefer cobble or boulder and inhabited for velocity of 0.05-0.15 m/s. Clingers prefer pebble or cobble and inhabited for velocity of 0.06-0.15 m/s. They were found to be determined mainly by the flow velocity.

Keywords: benthic macroinvertebrates, riffles, clinger, swimmer, burrower, sprawler

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Authors: M. F. Mamabolo

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Mining activities are identified as the most significant source of heavy metal contamination in river basins, due to inadequate disposal of mining waste thus resulting in acid mine drainage. Waste materials generated from gold mining and processing have severe and widespread impacts on water resources. Therefore, a total of 30 water samples were collected from Fig Tree Creek, Kaapriver, Sheba mine stream & Sauid kaap river to investigate the impact of gold mines on the Kaap River system. Physicochemical parameters (pH, EC and TDS) were taken using a BANTE 900P portable water quality meter. The concentration of Fe, Cu, Co, and SO₄²⁻ in water samples were analysed using Inductively Coupled Plasma-Mass spectrophotometry (ICP-MS) at 0.01 mg/L. The results were compared to the regulatory guideline of the World Health Organization (WHO) and the South Africa National Standards (SANS). It was found that Fe, Cu and Co were below the guideline values while SO₄²⁻ detected in Sheba mine stream exceeded the 250 mg/L limit for both seasons, attributed by mine wastewater. SO₄²⁻ was higher in wet season due to high evaporation rates and greater interaction between rocks and water. The pH of all the streams was within the limit (≥5 to ≤9.7), however EC of the Sheba mine stream, Suid Kaap River & where the tributary connects with the Fig Tree Creek exceeded 1700 uS/m, due to dissolved material. The TDS of Sheba mine stream exceeded 1000 mg/L, attributed by high SO₄²⁻ concentration. While the tributary connecting to the Fig Tree Creek exceed the value due to pollution from household waste, runoff from agriculture etc. In conclusion, the water from all sampled streams were safe for consumption due to low concentrations of physicochemical parameters. However, elevated concentration of SO₄²⁻ should be monitored and managed to avoid water quality deterioration in the Kaap River system.

Keywords: Kaap river system, mines, heavy metals, sulphate

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Authors: P. M. Natarajan, Shambhu Kallolikar, S. Ganesh

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By size and volume of water, Ganges River basin is the biggest among the fourteen major river basins in India. By Hindu’s faith, it is the main ‘holy river’ in this nation. But, of late, the pollution load, both domestic and industrial sources are deteriorating the surface and groundwater as well as land resources and hence the environment of the Ganges River basin is under threat. Seeing this scenario, the Indian government began to reclaim this river by two Ganges Action Plans I and II since 1986 by spending Rs. 2,747.52 crores ($457.92 million). But the result was no improvement in the water quality of the river and groundwater and environment even after almost three decades of reclamation, and hence now the New Indian Government is taking extra care to rejuvenate this river and allotted Rs. 2,037 cores ($339.50 million) in 2014 and Rs. 20,000 crores ($3,333.33 million) in 2015. The reasons for the poor water quality and stinking environment even after three decades of reclamation of the river are either no treatment/partial treatment of the sewage. Hence, now the authors are suggesting a tertiary level treatment standard of sewages of all sources and origins of the Ganges River basin and recycling the entire treated water for nondomestic uses. At 20million litres per day (MLD) capacity of each sewage treatment plant (STP), this basin needs about 2020 plants to treat the entire sewage load. Cost of the STPs is Rs. 3,43,400 million ($5,723.33 million) and the annual maintenance cost is Rs. 15,352 million ($255.87 million). The advantages of the proposed exercise are: we can produce a volume of 1,769.52 million m³ of biogas. Since biogas is energy, can be used as a fuel, for any heating purpose, such as cooking. It can also be used in a gas engine to convert the energy in the gas into electricity and heat. It is possible to generate about 3,539.04 million kilowatt electricity per annum from the biogas generated in the process of wastewater treatment in Ganges basin. The income generation from electricity works out to Rs 10,617.12million ($176.95million). This power can be used to bridge the supply and demand gap of energy in the power hungry villages where 300million people are without electricity in India even today, and to run these STPs as well. The 664.18 million tonnes of sludge generated by the treatment plants per annum can be used in agriculture as manure with suitable amendments. By arresting the pollution load the 187.42 cubic kilometer (km³) of groundwater potential of the Ganges River basin could be protected from deterioration. Since we can recycle the sewage for non-domestic purposes, about 14.75km³ of fresh water per annum can be conserved for future use. The total value of the water saving per annum is Rs.22,11,916million ($36,865.27million) and each citizen of Ganges River basin can save Rs. 4,423.83/ ($73.73) per annum and Rs. 12.12 ($0.202) per day by recycling the treated water for nondomestic uses. Further the environment of this basin could be kept clean by arresting the foul smell as well as the 3% of greenhouse gages emission from the stinking waterways and land. These are the ways to reclaim the waterways of Ganges River basin from deterioration.

Keywords: Holy Ganges River, lifeline of India, wastewater treatment and management, making Ganges permanently holy

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Authors: Abul Kalam Azad

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Water security has become an increasingly important issue both at the national and international levels. Bangladesh having an abundance of water during monsoon while the shortage of water during the dry season is far from being water secured. Though water security has been discussed discretely at a different level but a holistic effort to ensure water security is yet to be made. The elements of water security such as sectoral demands of water, conflicting requirements amongst the sectors, balancing between demand and supply including the quality of water can best be understood and managed in a catchment as it is the standard functioning unit. The Arial Khan River catchment consists of parts of Faridpur, Madaripur, Shariatpur and Barishal districts have all the components of water demands such as agriculture, domestic, commercial, industrial, forestry, fisheries, navigation or recreation and e-flow requirements. Based on secondary and primary data, water demands of various sectors have been determined. CROPWAT 8.0 has been used to determine the Agricultural Water Demand. Mean Annual Flow (MAF) and Flow Duration Curve (FDC) have been used to determine the e-flow requirements. Water Evaluation and Planning System (WEAP) based decision support tool as part of Integrated Water Resources Management (IWRM) has been utilized for ensuring the water security of the Arial Khan River catchment. Studies and practice around the globe connected with water security were consulted to mitigate the pressure on demand and supply including the options available to ensure the water security. Combining all the information, a framework for ensuring water security has been suggested for Arial Khan River catchment which can further be projected to river basin as well as for the country. This will assist planners and researchers to introduce the model for integrated water resources management of any catchment/river basins.

Keywords: water security, water demand, water supply, WEAP, CROPWAT

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Authors: N. H. Adenan, M. S. M. Noorani

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River flow prediction is an essential to ensure proper management of water resources can be optimally distribute water to consumers. This study presents an analysis and prediction by using nonlinear prediction method involving monthly river flow data in Tanjung Tualang from 1976 to 2006. Nonlinear prediction method involves the reconstruction of phase space and local linear approximation approach. The phase space reconstruction involves the reconstruction of one-dimensional (the observed 287 months of data) in a multidimensional phase space to reveal the dynamics of the system. Revenue of phase space reconstruction is used to predict the next 72 months. A comparison of prediction performance based on correlation coefficient (CC) and root mean square error (RMSE) have been employed to compare prediction performance for nonlinear prediction method, ARIMA and SVM. Prediction performance comparisons show the prediction results using nonlinear prediction method is better than ARIMA and SVM. Therefore, the result of this study could be used to developed an efficient water management system to optimize the allocation water resources.

Keywords: river flow, nonlinear prediction method, phase space, local linear approximation

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Authors: F.I. Adeosun, A.A. Idowu, D.O. Odulate,

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The aims of carrying out this experiment were to determine the water quality and to investigate if the various human and ecological activities around the river have any effect on the physico-chemical parameters of the river’s resources with a view to effectively utilizing these resources. Water samples were collected from two stations on the surface water of Lower Ogun River Akomoje biweekly for a period of 5 months (January to May, 2011). Results showed that temperature ranged between 24.0-30.7oC, transparency (0.53-1.00 m), depth (1.0-3.88 m), alkalinity (4.5-14.5 mg/l), nitrates (0.235-5.445 mg/l), electrical conductivity (140-190µS/cm), dissolved oxygen (4.12-5.32 mg/l), phosphates (0.02 mg/l-0.7 5 mg/l) and total dissolved solids (70-95).The parameters at the deep end (station A) accounted for the bulk of the highest values; there was however no significant differences between the stations at P˂0.05 with the exception of transparency, depth, total dissolved solids and electrical conductivity. The phosphate value was relatively low which accounted for the low productivity and high transparency. The results obtained from the physico-chemical parameters agreed with the limits set by both national and international bodies for drinking and fish growth. It was however observed that during the period of data collection, catch was low and this could be attributed to low level of primary productivity due to the quality of physico-chemical parameters of the water. It is recommended that the agencies involved in the management of the river should put the right policies in place that will effectively enhance proper exploitation of the water resources. More research should also be carried out on the physico-chemical parameters since this work only studied the water for five months.

Keywords: physical, chemical, parameters, water quality, Ogunriver

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Authors: J. P. Gorninski, J. M. L. Reis

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This present work was aimed to develop polymeric mortars having as binder two polyester resins namely isophtalic and orthophtalic polyester. The inorganic phase was composed by medium-size river sand and fly ash fíller, a by-product of the burning of coal in power plants. The compositions in this study are high performance mortars and were assessed by mechanical properties, through compressive strength and flexural strength, by durability strength when exposed to the cyclical variation of temperature from -400C to +300C and by the chemical aggression test. The composites displayed good performance when exposed to cyclical temperature variations and chemical solutions. The mechanical strength values reached the 100 MPa, the flexural strength yielded values of about twenty percent of mechanical strength.

Keywords: polymer mortar, mechanical strength, cyclical temperatures, chemical strength, sustainability

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Authors: Juliana C. Alencar, Monica Ferreira do Amaral Porto

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Watercourses in Brazilian urban areas are constantly being degraded due to the unplanned use of the urban space; however, due to the different contexts of land use and occupation in the river watersheds, different intervention strategies are required to requalify them. When it comes to requalifying watercourses, we can list three main techniques to fulfill this purpose: restoration, revitalization and recovery; each one being indicated for specific contexts of land use and occupation in the basin. In this study, it was demonstrated that the application of these three techniques to three small basins in São Paulo city, listing the aspects involved in each of the contexts and techniques of requalification. For a protected watercourse within a forest park, renaturalization was proposed, where the watercourse is preserved in a state closer to the natural one. For a watercourse in an urban context that still preserves open spaces for its maintenance as a landscape element, an intervention was proposed following the principles of revitalization, integrating the watercourse with the landscape and the population. In the case of a watercourse in a harder context, only recovery was proposed, since the watercourse is found under the road system, which makes it difficult to integrate it into the landscape.

Keywords: sustainable drainage, river restoration, river revitalization, river recovery

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Authors: P. Acosta-Santamaría, A. Ibatá-Soto, A. López-Vásquez

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Organic compounds in wastewaters coming from textile and pharmaceutical industry generated multiple harmful effects on the environment and the human health. One of them is the methyl orange (MeO), an azoic dye considered to be a recalcitrant compound. The heterogeneous photocatalysis emerges as an alternative for treating this type of hazardous compounds, through the generation of OH radicals using radiation and a semiconductor oxide. According to the author’s knowledge, catalysts such as TiO₂ doped with metals show high efficiency in degrading MeO; however, this presents economic limitations on industrial scale. Black sand can be considered as a naturally doped catalyst because in its structure is common to find compounds such as titanium, iron and aluminum oxides, also elements such as zircon, cadmium, manganese, etc. This study reports the photocatalytic activity of the mineral black sand used as semiconductor in the discoloration of MeO by oxidation and reduction photocatalytic techniques. For this, magnetic composites from the mineral were prepared (RM, M1, M2 and NM) and their activity were tested through MeO discoloration while TiO₂ was used as reference. For the fractions, chemical, morphological and structural characterizations were performed using Scanning Electron Microscopy with Energy Dispersive X-Ray (SEM-EDX), X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF) analysis. M2 fraction showed higher MeO discoloration (93%) in oxidation conditions at pH 2 and it could be due to the presence of ferric oxides. However, the best result to reduction process was using M1 fraction (20%) at pH 2, which contains a higher titanium percentage. In the first process, hydrogen peroxide (H₂O₂) was used as electron donor agent. According to the results, black sand mineral can be used as natural semiconductor in photocatalytic process. It could be considered as a photocatalyst precursor in such processes, due to its low cost and easy access.

Keywords: black sand mineral, methyl orange, oxidation, photocatalysis, reduction

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Authors: Saeed Talamkhani, Seyed Abolhassan Naeini

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In recent years, the occurrence of several liquefactions in sandy soils containing various values of clay content has shown that in addition to silty sands, clayey sands are also susceptible to liquefaction. Therefore, it is necessary to investigate the properties of these soil compositions and their behavioral characteristics. This paper presents the effect of clay fines on the undrained shear strength of sands at various confining pressures. For this purpose, a series of unconsolidated undrained triaxial shear tests were carried out on clean sand and sand mixed with 5, 10, 15, 20, and 30 percent of clay fines. It was found that the presence of clay particle in sandy specimens change the dilative behavior to contraction. The result also showed that increasing the clay fines up to 10 percent causes to increase the potential for liquefaction, and decreases it at higher values fine content. These results reveal the important role of clay particles in changing the undrained strength of the sandy soil.

Keywords: clayey sand, liquefaction, triaxial test, undrained shear strength

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Authors: Ashirgul Kozhagulova, Ainash Shabdirova, Galym Tokazhanov, Minh Nguyen

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The synthetic rocks have been advantageous over the natural rocks in terms of availability and the consistent studying the impact of a particular parameter. The artificial rocks can be fabricated using variety of techniques such as mixing sand and Portland cement or gypsum, firing the mixture of sand and fine powder of borosilicate glass or by in-situ precipitation of calcite solution. In this study, sodium silicate solution has been used as the cementing agent for the quartz sand. The molded soft cylindrical sandstone samples are placed in the gas-tight pressure vessel, where the hardening of the material takes place as the chemical reaction between carbon dioxide and the silicate solution progresses. The vessel allows uniform disperse of carbon dioxide and control over the ambient gas pressure. Current paper shows how the bonding material is initially distributed in the intergranular space and the surface of the sand particles by the usage of Electron Microscopy and the Energy Dispersive Spectroscopy. During the study, the strength of the cement bond as a function of temperature is observed. The impact of cementing agent dosage on the micro and macro characteristics of the sandstone is investigated. The analysis of the cement bond at micro level helps to trace the changes to particles bonding damage after a potential yielding. Shearing behavior and compressional response have been examined resulting in the estimation of the shearing resistance and cohesion force of the sandstone. These are considered to be main input values to the mathematical prediction models of sand production from weak clastic oil reservoir formations.

Keywords: artificial sanstone, cement bond, microstructure, SEM, triaxial shearing

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Authors: Olaniyan Rotimi Francis

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Agbabu Water, Oluwa River is used for artisanal fishing, ferrying and domestic activities in Odigbo Local Government Area (OLGA), Ondo State. The river receives bitumen spills and domestic and agricultural wastes, which could adversely impact on the water quality and resident biota. In spite of anthropogenic activities, there is a dearth of information on the limnology and biota of the river. Extensive bitumen spills, as well as uncontrolled discharge of domestic wastes have pollution implications as they alter prevailing conditions and destroy the habitats of aquatic organisms. The aim of this study was to investigate the physic-chemical parameters of Agbabu Water in order to provide baseline information for effective management. Monthly water samples were collected on the surface of Agbabu water, Oluwa River, for a period of 6 months (June,2024 to November,2024). All physic-chemicals were collected and analyzed according to APHA (2005) standard methods. Results showed that temperature ranged between 26.0-32.0oC, transparency (1.0-8.0 m), alkalinity (14.0-25.0 mg/l), electrical conductivity (18-105 µS/cm), dissolved oxygen (1.2-3.8 mg/l), sulphate (0.0 -4.0mg/l) and total dissolved solids (18-36). The parameters at the downstream (station A) accounted for the bulk of the highest values; there were, however, no significant differences between the stations at P<0.05. The results obtained from the physic-chemical parameters agree with the limits set by both national and international bodies for drinking and fish growth. It was recommended that urgent checks and monitoring by relevant agencies, government representatives, public health practitioners, and community leaders are required.

Keywords: physico-chemical, water, Agbabu, River

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Authors: Pinna Beatrice., Laini Alex, Negro Giovanni, Burgazzi Gemma, Viaroli Pierluigi, Vezza Paolo

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Habitat models rarely consider macroinvertebrates as ecological targets in rivers. Available approaches mainly focus on single macroinvertebrate species, not addressing the ecological needs and functionality of the entire community. This research aimed to provide an approach to model the habitat of the macroinvertebrate community. The approach is based on the recently developed Flow-T index, together with a Random Forest (RF) regression, which is employed to apply the Flow-T index at the meso-habitat scale. Using different datasets gathered from both field data collection and 2D hydrodynamic simulations, the model has been calibrated in the Trebbia river (2019 campaign), and then validated in the Trebbia, Taro, and Enza rivers (2020 campaign). The three rivers are characterized by a braiding morphology, gravel riverbeds, and summer low flows. The RF model selected 12 mesohabitat descriptors as important for the macroinvertebrate community. These descriptors belong to different frequency classes of water depth, flow velocity, substrate grain size, and connectivity to the main river channel. The cross-validation R² coefficient (R²𝒸ᵥ) of the training dataset is 0.71 for the Trebbia River (2019), whereas the R² coefficient for the validation datasets (Trebbia, Taro, and Enza Rivers 2020) is 0.63. The agreement between the simulated results and the experimental data shows sufficient accuracy and reliability. The outcomes of the study reveal that the model can identify the ecological response of the macroinvertebrate community to possible flow regime alterations and to possible river morphological modifications. Lastly, the proposed approach allows extending the MesoHABSIM methodology, widely used for the fish habitat assessment, to a different ecological target community. Further applications of the approach can be related to flow design in both perennial and non-perennial rivers, including river reaches in which fish fauna is absent.

Keywords: ecological flows, macroinvertebrate community, mesohabitat, river habitat modeling

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Authors: Hemant Kumar

Abstract:

Brahmaputra River is known according to the Hindu mythology the son of the Lord Brahma. According to this name, the river Brahmaputra creates mass destruction during the monsoon season in Assam, India. It is a state situated in North-East part of India. This is one of the essential states out of the seven countries of eastern India, where almost all entire Brahmaputra flow carried out. The other states carry their tributaries. In the present case study, the spatial analysis performed in this specific case the number of MODIS data are acquired. In the method of detecting the change, the spray content was found during heavy rainfall and in the flooded monsoon season. By this method, particularly the analysis over the Brahmaputra outflow determines the flooded season. The charged particle-associated in aerosol content genuinely verifies the heavy water content below the ground surface, which is validated by trend analysis through rainfall spectrum data. This is confirmed by in-situ sampled view data from a different position of Brahmaputra River. Further, a Hyperion Hyperspectral 30 m resolution data were used to scan the sediment deposits, which is also confirmed by in-situ sampled view data from a different position.

Keywords: aerosol, change detection, spatial analysis, trend analysis

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Authors: Abadou Yacine, Faid Hayette

Abstract:

Significant investigations were performed on the use and impact on physical properties along with the mechanical strength of the recycled and reused E-glass waste powder. However, it has been modelled how recycled display e-waste glass may affect the characteristics and qualities of dune sand mortar. To be involved in this field, an investigation has been done with the substitution of dune sand for recycled E-glass waste and constant water-cement ratios. The linear relationship between the dune sand mortar and E-glass mortar mix % contributes to the model's reliability. The experimental data was exposed to regression analysis using JMP Statistics software. The regression model with one predictor presented the general form of the equation for the prediction of the five properties' characteristics of dune sand mortar from the substitution ratio of E-waste glass and curing age. The results illustrate that curing a long-term process produced an E-glass waste mortar specimen with the highest compressive strength of 68 MPa in the laboratory environment. Anova analysis indicated that the curing at long-term has the utmost importance on the sorptivity level and ultrasonic pulse velocity loss. Furthermore, the E-glass waste powder percentage has the utmost importance on the compressive strength and improvement in dynamic elasticity modulus. Besides, a significant enhancement of radiation-shielding applications.

Keywords: ANOVA analysis, E-glass waste, durability and sustainability, radiation-shielding

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Authors: Sito Ismanti, Noriyuki Yasufuku

Abstract:

Cement utilization to improve the properties of soil is a well-known method applied in field. However, its addition in large quantity must be controlled. This study presents utilization of natural and environmental-friendly material mixed with small amount of cement content in soil improvement, i.e. bamboo chips. Absorbability, elongation, and flatness ratio of bamboo chips were examined to investigate and understand the influence of its characteristics in the mixture. Improvement of dilation behavior as a problem of loose and poorly graded sand soil is discussed. Bamboo chips are able to improve the permeability value that affects the dilation behavior of cemented sand soil. It is proved by the stress path as the result of triaxial compression test in the undrained condition. The effect of size and content variation of bamboo chips, as well as the curing time variation are presented and discussed.  

Keywords: bamboo chips, permeability, mechanical properties, triaxial compression

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Authors: Afolabi O.J, Simon-Oke I.A., Oniya M.O., Okaka C.E.

Abstract:

River blindness is a skin, and an eye disease caused by Onchocerca volvulus and vectored by a female hematophagous blackfly. The study aims to evaluate the distribution of the clinical signs of river blindness and the efficacy of ivermectin in the treatment of river blindness in Idogun. Observational studies in epidemiology that involve the use of a structured questionnaire to obtain useful epidemiological information from the respondents, physical assessment via palpation from head to ankle was used to assess clinical signs from the respondents and skin snip test was used to evaluate the prevalence of the disease. The efficacy of the drug was evaluated and expressed in percentages. One hundred and ninety-two (192) out of the 384 respondents examined, showed various signs of river blindness. However, it was only 108 (28.1%) respondents with the clinical signs that demonstrated Onchocerca volvulus microfilariae in their skin snips. The clinical signs observed among the respondents include skin depigmentation such as dermatitis, leopard skin, papules, pruritus and self-inflicted injury, while ocular symptoms include cataract, ocular lesion and partial blindness. Among these clinical signs, papules, and pruritus were the most dominant in the community. The prevalence of the clinical signs was observed to vary significantly among the age groups and gender (P<0.05). The efficacy of the drug after 6 and 12 months of treatments shows that the drug is more effective at age groups 10-50 years than the age groups 51-90 years. Ivermectin is observed to be efficacious in the treatment of the disease. However, to achieve eradication of the disease, the drug may be administered at 0.15mg/kg twice a year.

Keywords: riverblindness, clinical signs, ivermectin, Idogun

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Authors: Lucien N. James, Mulala D. Simatele

Abstract:

As a country that already faces hydrological and climatological challenges, South Africa’s socio-economic situation only complicates water resource management. This is observable through the state of rivers in the Gauteng Province such as the Hennops and Jukskei which are plagued by pollution from surrounding urban areas. While communities in the Hennops River basin contribute to its degradation, their potential in improved water resource management strategies is yet to be established. Therefore, the aim of this study was to investigate the myriad of ways in which stakeholder and community engagement, mobilisation, as well as participation can be harnessed in contested urban spaces to facilitate a sustainable management system for river basins. Through meetings, clean-up campaigns, and a community workshop, the community of Tembisa and several key informants were engaged. The role of communities and their perceptions on an integrated and participatory approach to solving the Hennops River basin’s current pollution crisis were therefore explored. The findings of this study suggest that meaningful participation is tied to the level of awareness within communities as well as the amount of support attributed to active involvement through the initiatives of stakeholders such as NonGovernmental Organisations. For meaningful participation to take place, more needs to be done to shift communities away from a “bystander” position to a more active role. An approach to community engagement is therefore proposed arguing for the further support of stakeholder-driven initiatives and the raising of awareness around environmental challenges in poorer communities. The findings of this study demonstrate the value of engagement with stakeholders and communities, highlighting ways through which better water management and environmental governance can be achieved in South Africa.

Keywords: community participation, integrated water resource management, river basin management, stakeholder engagement

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Authors: Davendra Singh Malik

Abstract:

India is one of the mega-biodiversity countries in the world and contributing about 11.72% of global fish diversity. The Yamuna river is the longest tributary of Ganga river ecosystem, providing a natural habitat for existing fish diversity of Himalayan region of Indian subcontinent. The several hydropower dams and barrages have been constructed on different locations of major rivers in Garhwal region. These dams have caused a major ecological threat to change existing fresh water ecosystems altering water flows, interrupting ecological connectivity, fragmenting habitats and native riverine fish species. Mahseer fishes (Indian carp) of the genus Tor, are large cyprinids endemic to continental Asia popularly known as ‘Game or sport fishes’ have continued to be decimated by fragmented natural habitats due to damming the water flow in riverine system and categorized as threatened fishes of India. The fresh water fish diversity as 24 fish species were recorded from Yamuna river. The present fish catch data has revealed that mahseer fishes (Tor tor and Tor putitora) were contributed about 32.5 %, 25.6 % and 18.2 % in upper, middle and lower riverine stretches of Yaumna river. The length range of mahseer (360-450mm) recorded as dominant size of catch composition. The CPUE (catch per unit effort) of mahseer fishes also indicated about a sharp decline of fish biomass, changing growth pattern, sex ratio and maturity stages of fishes. Only 12.5 – 14.8 % mahseer female brooders have showed only maturity phases in breeding months. The fecundity of mature mahseer female fish brooders ranged from 2500-4500 no. of ova during breeding months. The present status of mahseer fishery has attributed to the over exploitative nature in Yamuna river. The mahseer population is shrinking continuously in down streams of Yamuna river due to cumulative effects of various ecological stress. Mahseer conservation programme have implemented as 'in situ fish conservation' for enhancement of viable population size of mahseer species and restore the genetic loss of mahseer fish germplasm in Yamuna river of Garhwal Himalayan region.

Keywords: conservation practice, population dynamics, tor fish species, Yamuna River

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Authors: Alaa H. J. Al-Rkaby, A. Chegenizadeh, H. R. Nikraz

Abstract:

Anisotropy is one of the major aspects that affect soil behavior, and extensive efforts have investigated its effect on the mechanical properties of soil. However, very little attention has been given to the combined effect of anisotropy and fine contents. Therefore, in this paper, the anisotropic strength of sand containing different fine content (F) of 5%, 10%, 15%, and 20%, was investigated using hollow cylinder tests under different principal stress directions of α = 0° and α = 90°. For a given principal stress direction (α), it was found that increasing fine content resulted in decreasing deviator stress (q). Moreover, results revealed that all fine contents showed anisotropic strength where there is a clear difference between the strength under 0° and the strength under 90°. This anisotropy was greatest under F = 5% while it decreased with increasing fine contents, particularly at F = 10%. Mixtures with low fine content show low contractive behavior and tended to show more dilation. Moreover, all sand-clay mixtures exhibited less dilation and more compression at α = 90° compared with that at α = 0°.

Keywords: anisotropy, principal stress direction, fine content, hollow cylinder sample

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