Search results for: sand source

Authors: Dilip Nath

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A study has been conducted on the available aquatic invertebrates in the river Dhansiri at Dimapur site. The study confirmed that the river body composed of aquatic macroinvertebrate community under two phyla viz., Arthropods and Molluscs. Total 10 species have been identified from there as the source of alternative protein food for the common people. Not only the protein source, they are also the component of aquatic food chain and indicators of aquatic ecosystem. Proper management and strategies to promote the edible invertebrates can be considered as the alternative protein and alternative income source for the common people for sustainable livelihood improvement.

Keywords: Dhansiri, Dimapur, invertebrates, livelihood improvement, protein

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Authors: Pallavi Gajjar, Vinayak Malhotra

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Rockets have been known to have played a predominant role in spacecraft propulsion. The quintessential aspect of combustion-related requirements of a rocket engine is the minimization of the surrounding risks/hazards. Over time, it has become imperative to understand the combustion rate variation in presence of external energy source(s). Rocket propulsion represents a special domain of chemical propulsion assisted by high speed flows in presence of acoustics and thermal source(s). Jet noise leads to a significant loss of resources and every year a huge amount of financial aid is spent to prevent it. External heat source(s) induce high possibility of fire risk/hazards which can sufficiently endanger the operation of a space vehicle. Appreciable work had been done with justifiable simplification and emphasis on the linear variation of external energy source(s), which yields good physical insight but does not cater to accurate predictions. Present work experimentally attempts to understand the correlation between inter-energy conversions with the non-linear placement of external energy source(s). The work is motivated by the need to have better fire safety and enhanced combustion. The specific objectives of the work are a) To interpret the related energy transfer for combustion in presence of alternate external energy source(s) viz., thermal and acoustic, b) To fundamentally understand the role of key controlling parameters viz., separation distance, the number of the source(s), selected configurations and their non-linear variation to resemble real-life cases. An experimental setup was prepared using incense sticks as potential fuel and paraffin wax candles as the external energy source(s). The acoustics was generated using frequency generator, and source(s) were placed at selected locations. Non-equidistant parametric experimentation was carried out, and the effects were noted on regression rate changes. The results are expected to be very helpful in offering a new perspective into futuristic rocket designs and safety.

Keywords: combustion, acoustic energy, external energy sources, regression rate

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Authors: Mohamed Rajab Peer Mohamed, Thiruvenkatasamy Kannabiran

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In the present investigation, the scour around a circular pier subjected to a steady current were studied numerically using two-dimensional MIKE21 Flow Model (FM) and Sand Transport (ST)Modulewhich is developed by Danish Hydraulic Institute (DHI), Denmark. The unstructured flexible mesh generated with rectangular flume dimension of 10 m wide, 1 m deep, and 30 m long. The grain size of the sand was d50 = 0.16 mm, sediment size, sediment gradation=1.16, pier diameter D= 30 mm and depth-averaged current velocity, U = 0.449 m/s are considered in the model. The estimated scour depth obtained from this model is validated and it is observed that the results of the model have good agreement with flume experimental results.In order to estimate the scour depth, several simulations were made for three cases viz., Case I:change in sediment transport model description in the numerical model viz, i) Engelund-Hansen model, ii) Engelund-Fredsøe model, and iii) Van Rijn model, Case II: change in current velocity for keeping constant pile diameter D=0.03 m and Case III:change in pier diameter for constant depth averaged current speed U=0.449 m/s.In case I simulations, the results indicate that the scour depth S/D is the order of 1.73 for Engelund-Hansen model, 0.64 for Engelund-Fredsøe model and 0.46 for VanRijn model. The scour depth estimates using Engelund-Hansen method compares well the experimental results.In case II, simulations show that the scour depth increases with increasing current component of the flow.In case III simulations, the results indicate that the scour depth increases with increase in pier diameter and it stabilize attains steady value when the Froude number> 2.71.All the results of the numerical simulations are clearly matches with reported values of the experimental results. Hence, this MIKE21 FM –Sand Transport model can be used as a suitable tool to estimate the scour depth for field applications. Moreover, to provide suitable scour protection methods, the maximum scour depth is to be predicted, Engelund-Hansen method can be adopted to estimate the scour depth in the steady current region.

Keywords: circular pier, MIKE21, numerical model, scour, sediment transport

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Authors: Meiling Yang, Shuguo Xie, Yilong Zhu

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Nowadays, due to diverse electric products and complex electromagnetic environment, the localization and troubleshooting of the electromagnetic radiation source is urgent and necessary especially on the condition of far field. However, based on the existing DOA positioning method, the system or devices are complex, bulky and expensive. To address this issue, this paper proposes a single antenna radiation source localization method. A single antenna moves to form a virtual antenna array combined with DOA and MUSIC algorithm to position accurately, meanwhile reducing the cost and simplify the equipment. As shown in the results of simulations and experiments, the virtual antenna array DOA estimation modeling is correct and its positioning is credible.

Keywords: virtual antenna array, DOA, localization, far field

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Authors: Panpan Xu, Qiying Zhang, Hui Qian

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Groundwater is main source of water supply in the Guanzhong Basin, China. To investigate the quality of groundwater for agricultural purposes in Jiaokou Irrigation District located in the east of the Guanzhong Basin, 141 groundwater samples were collected for analysis of major ions (K⁺, Na⁺, Mg²⁺, Ca²⁺, SO₄^2-, Cl^-, HCO₃^-, and CO₃^2-), pH, and total dissolved solids (TDS). Sodium percentage (Na%), residual sodium carbonate (RSC), magnesium hazard (MH), and potential salinity (PS) were applied for irrigation water quality assessment. In addition, multivariate statistical techniques were used to identify the underlying hydrogeochemical processes. Results show that the content of TDS mainly depends on Cl^-, Na⁺, Mg²⁺, and SO₄^2-, and the HCO₃^- content is generally high except for the eastern sand area. These are responsible for complex hydrogeochemical processes, such as dissolution of carbonate minerals (dolomite and calcite), gypsum, halite, and silicate minerals, the cation exchange, as well as evaporation and concentration. The average evaluation levels of Na%, RSC, MH, and PS for irrigation water quality are doubtful, good, unsuitable, and injurious to unsatisfactory, respectively. Therefore, it is necessary for decision makers to comprehensively consider the indicators and thus reasonably evaluate the irrigation water quality.

Keywords: irrigation water quality, multivariate statistical analysis, groundwater, hydrogeochemical process

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Authors: Mayowa Philips Ibitola, Abe Oluwaseun Banji, Olorunfemi Akinade-Solomon

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A total of 20 bottom sediment samples were collected from the Lekki Lagoon during the wet and dry season. The study was carried out to determine the textural characteristics, sediment distribution pattern and energy of transportation within the lagoon system. The sediment grain sizes and depth profiling was analyzed using dry sieving method and MATLAB algorithm for processing. The granulometric reveals fine grained sand both for the wet and dry season with an average mean value of 2.03 ϕ and -2.88 ϕ, respectively. Sediments were moderately sorted with an average inclusive standard deviation of 0.77 ϕ and -0.82 ϕ. Skewness varied from strongly coarse and near symmetrical 0.34- ϕ and 0.09 ϕ. The kurtosis average value was 0.87 ϕ and -1.4 ϕ (platykurtic and leptokurtic). Entirely, the bathymetry shows an average depth of 4.0 m. The deepest and shallowest area has a depth of 11.2 m and 0.5 m, respectively. High concentration of fine sand was observed at deep areas compared to the shallow areas during wet and dry season. Statistical parameter results show that the overall sediments are sorted, and deposited under low energy condition over a long distance. However, sediment distribution and sediment transport pattern of Lekki Lagoon is controlled by a low energy current and the down slope configuration of the bathymetry enhances the sorting and the deposition rate in the Lekki Lagoon.

Keywords: Lekki Lagoon, Marine sediment, bathymetry, grain size distribution

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Authors: Alim Asamatdinov

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Superabsorbent polymer hydrogels can swell to absorb huge volumes of water or aqueous solutions. This property has led to many practical applications of these new materials, particularly in agriculture for improving the water retention of soils and the water supply of plants. This article reviews the methods of polymeric hydrogels, measurements and treatments of their properties, as well as their effects on soil and on plant growth. The thermodynamic approach used to describe the swelling behaviour of polymer networks proves to be quite helpful in modelling the hydrogel efficiency of water-absorbing additives. The paper presents the results of a study of the physical and chemical properties of hydrogels based on of the production of "Nitron" (Polyacrylonitrile) wastes fibre and salts of the 3-rd transition metals and formalin. The developed hydrogels HG-Al, HG-Cr and HG-formalin have been tested for water holding the capacity of sand. Such a conclusion was also confirmed by data from the method of determining the wilting point by vegetative thumbnails. In the entering process using a dose of 0.1% of the swelling polymeric hydrogel in sand with a culture of barley the difference between the wilting point in comparison with the control was negligible. This indicates that the moisture which was contained in the hydrogel is involved in moisture availability for plant growth, to the same extent as that in the capillaries.

Keywords: hydrogel, chemical, polymer, sandy, colloid

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Authors: M. R. Martinez-Torres, S. L. Toral, M. Olmedilla

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Typically, virtual communities exhibit the well-known phenomenon of participation inequality, which means that only a small percentage of users is responsible of the majority of contributions. However, the sustainability of the community requires that the group of active users must be continuously nurtured with new users that gain expertise through a participation process. This paper analyzes the time evolution of Open Source Software (OSS) communities, considering users that join/abandon the community over time and several topological properties of the network when modeled as a social network. More specifically, the paper analyzes the role of those users rejoining the community and their influence in the global characteristics of the network.

Keywords: open source communities, social network Analysis, time series, virtual communities

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Authors: Rahul Thakur, Onkar Chandel

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Red Hat is the world leader in providing open source software and solutions. A global enterprise, like Red Hat, has unique issues of connecting employees with content because of distributed offices, multiple teams spread across geographies, multiple languages, and different cultures. Employees, of a global company, create content that is distributed across departments, teams, regions, and countries. This makes finding the best content difficult since owners keep iterating on the existing content. When employees are unable to find the content, they end up creating it once again and in the process duplicating existing material and effort. Also, employees may not find the relevant content and spend time reviewing obsolete duplicate, or irrelevant content. On an average, a person spends 15 minutes/day in failed searches that might result in missed business opportunities, employee frustration, and substandard deliverables. Red Hat Knowledge Management Office (KMO) applied 'open source strategy' to solve the above problems. Under the Open Source Strategy, decisions are taken collectively. The strategy aims at accomplishing common goals with the help of communities. The objectives of this initiative were to save employees' time, get them authentic content, improve their content search experience, avoid duplicate content creation, provide context based search, improve analytics, improve content management workflows, automate content classification, and automate content upload. This session will describe open source strategy, its applicability in content management, challenges, recommended solutions, and outcome.

Keywords: content classification, content management, knowledge management, open source

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Authors: Saber Noie

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This research follows some objectives to consider the mystic terms as one of the main issues in translation of poems. Firstly, it is an attempt to find out what strategies have been used to find equivalents for source text mystic. Second, it is hoped that this study of the translations of the mystic terms in Attar’s poems will further address and explore the problems in translating mystic texts, proposed by other Persian poets and suggest instructional points from Davis work for translation education. In order to deal with such a breadth of work, a new conceptual tool was developed, as explained by Van Doorslaer (2007). This study shows that according to Van Doorslaer’s map, the mystic terms can be transferred to the target language (TL) with their exact content of the source language (SL) if the translator has a good choice for any term.

Keywords: metaphor, mystic, mysticism, source language (SL), target language (TL)

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Authors: Mohamed Khiatine, Amal Medjnoun, Ramdane Bahar

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The North Algeria is a highly seismic zone, as evidenced by the historical seismicity. During the past two decades, it has experienced several moderate to strong earthquakes. Therefore, the geotechnical engineering problems that involve dynamic loading of soils and soil-structure interaction system requires, in the presence of saturated loose sand formations, liquefaction studies. Bejaia city, located in North-East of Algiers, Algeria, is a part of the alluvial plain which covers an area of approximately 750 hectares. According to the Algerian seismic code, it is classified as moderate seismicity zone. This area had not experienced in the past urban development because of the different hazards identified by hydraulic and geotechnical studies conducted in the region. The low bearing capacity of the soil, its high compressibility and the risk of liquefaction and flooding are among these risks and are a constraint on urbanization. In this area, several cases of structures founded on shallow foundations have suffered damages. Hence, the soils need treatment to reduce the risk. Many field and laboratory investigations, core drilling, pressuremeter test, standard penetration test (SPT), cone penetrometer test (CPT) and geophysical down hole test, were performed in different locations of the area. The major part of the area consists of silty fine sand , sometimes heterogeneous, has not yet reached a sufficient degree of consolidation. The ground water depth changes between 1.5 and 4 m. These investigations show that the liquefaction phenomenon is one of the critical problems for geotechnical engineers and one of the obstacles found in design phase of projects. This paper presents an analysis to evaluate the liquefaction potential, using the empirical methods based on Standard Penetration Test (SPT), Cone Penetration Test (CPT) and shear wave velocity and numerical analysis. These liquefaction assessment procedures indicate that liquefaction can occur to considerable depths in silty sand of harbor zone of Bejaia.

Keywords: earthquake, modeling, liquefaction potential, laboratory investigations

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Authors: Muhammad Arsalan Khan Sherwani

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The use of Volatile Corrosion Inhibitors (VCI) to protect Aboveground Storage Tank (AST) bottom plates against soil-side corrosion is one of the emerging corrosion prevention methods, specifically for tanks constructed on oily sand pad. Oily sand pad and the presence of air gaps underneath the bottom plates lead to severe corrosion and high metal thickness loss. In such cases, the cathodic protection cannot be fully considered as effective due to Cathodic Protection (CP) current shielding. These situations sometimes result in serious failures on multiple fronts, such as; containment losses, system shutdowns, extensive repairs, environmental impact and safety concerns in case of flammable fluids. Recently, East West Pipeline Department (EWPD) of Saudi Aramco has deployed this technology to one of the crude oil storage tanks, which showed high metal thickness loss during its out of service inspection. Soil-side corrosion rustled in major repairs of bottom plates and ultimately caused enormous unplanned activities in term of time as well as cost. This paper mainly focuses on the methodology of VCI installation, corrosion monitoring system and the expected results of protection.

Keywords: Vapor Corrosion Inhibitor, Soil Side Corrosion, External Corrosion, Above Grade Storage Tank

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Authors: Narsimhulu Sanke, D. N. Reddy

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The purpose of the paper is to discuss the biomass as a renewable source of energy for power generation. The setup is designed and fabricated in the Centre for Energy Technology (CET) and four different fuels are tested in the laboratory, but here the focus is on wood blocks (fuel) combustion with temperature, gas composition percentage by volume and the heating values.

Keywords: biomass, downdraft gasifier, power generation, renewable energy sources

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Authors: G. Adelian, A. Mirzaii, S. S. Yasrobi

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This paper represents data of an extensive experimental laboratory testing program for the measurement of the water coefficient of permeability of clayey sand in different hydraulic and mechanical boundary conditions. A novel permeameter was designed and constructed for the experimental testing program, suitable for the study of flow in unsaturated soils in different hydraulic and mechanical loading conditions. In this work, the effect of hydraulic hysteresis, net isotropic confining stress, water flow condition, and sample dimensions are evaluated on the water coefficient of permeability of understudying soil. The experimental results showed a hysteretic variation for the water coefficient of permeability versus matrix suction and degree of saturation, with higher values in drying portions of the SWCC. The measurement of the water permeability in different applied net isotropic stress also signified that the water coefficient of permeability increased within the increment of net isotropic consolidation stress. The water coefficient of permeability also appeared to be independent of different applied flow heads, water flow condition, and sample dimensions.

Keywords: water permeability, unsaturated soils, hydraulic hysteresis, void ratio, matrix suction, degree of saturation

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Authors: Hamidreza Sahaleh

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In this paper, the authors display an incorporated secluded way to deal with quantitatively foresee volumetric sand generation and improved oil recuperation. This model is in light of blend hypothesis with erosion mechanics, in which multiphase hydrodynamics and geo-mechanics are coupled in a predictable way by means of principal unknowns, for example, saturation, pressure, porosity, and formation displacements. Foamy oil is demonstrated as a scattering of gas bubbles caught in the oil, where these gas air bubbles keep up a higher repository weight. A secluded methodology is then received to adequately exploit the current propelled standard supply and stress-strain codes. The model is actualized into three coordinated computational modules, i.e. erosion module, store module, and geo-mechanics module. The stress, stream and erosion mathematical statements are understood independently for every time addition, and the coupling terms (porosity, penetrability, plastic shear strain, and so on) are gone among them and iterated until certain union is accomplished on a period step premise. The framework is capable regarding its abilities, yet practical in terms of computer requirements and maintenance. Numerical results of field studies are displayed to show the capacities of the model. The impacts of foamy oil stream and sand generation are additionally inspected to exhibit their effect on the upgraded hydrocarbon recuperation.

Keywords: oil recuperation, erosion mechanics, foamy oil, erosion module.

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Authors: Rudi Ryacudu, Edi Artono, Gema Wahyudi Purnama

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Oil and gas consumption in Indonesia is currently on the rise due to its nation economic improvement. Unfortunately, Indonesia’s domestic oil production cannot meet it’s own consumption and Indonesia has lost its status as Oil and Gas exporter. Even worse, our conventional oil and gas reserve is declining. Unwilling to give up, the government of Indonesia has taken measures to invite investors to invest in domestic oil and gas exploration to find new potential reserve and ultimately increase production. Yet, it has not bear any fruit. Indonesia has taken steps now to explore new unconventional oil and gas play including Shale Gas, Shale Oil and Tight Sands to increase domestic production. These new plays require definite parameters to differentiate each concept. The purpose of this paper is to provide ways in defining unconventional hydrocarbon reservoir parameters in Shale Gas, Shale Oil and Tight Sands. The parameters would serve as an initial baseline for users to perform analysis of unconventional hydrocarbon plays. Some of the on going concerns or question to be answered in regards to unconventional hydrocarbon plays includes: 1. The TOC number, 2. Has it been well “cooked” and become a hydrocarbon, 3. What are the permeability and the porosity values, 4. Does it need a stimulation, 5. Does it has pores, and 6. Does it have sufficient thickness. In contrast with the common oil and gas conventional play, Shale Play assumes that hydrocarbon is retained and trapped in area with very low permeability. In most places in Indonesia, hydrocarbon migrates from source rock to reservoir. From this case, we could derive a theory that Kitchen and Source Rock are located right below the reservoir. It is the starting point for user or engineer to construct basin definition in relation with the tectonic play and depositional environment. Shale Play concept requires definition of characteristic, description and reservoir identification to discover reservoir that is technically and economically possible to develop. These are the steps users and engineers has to do to perform Shale Play: a. Calculate TOC and perform mineralogy analysis using water saturation and porosity value. b. Reconstruct basin that accumulate hydrocarbon c. Brittlenes Index calculated form petrophysical and distributed based on seismic multi attributes d. Integrated natural fracture analysis e. Best location to place a well.

Keywords: unconventional hydrocarbon, shale gas, shale oil tight sand reservoir parameters, shale play

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Authors: Fernando Valerio-Holguin

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Over the recent three decades, the tourism industry in the Dominican Republic has had an enormous impact on the country’s culture. The arrival of tourists from Germany, France, Italy, Russia and the United States has rewritten Dominican cultural identity and created a cultural palimpsest in the areas of language, gastronomy, habits, fashion, values, and gender relations. As a consequence of tourism, a prostitution network has flourished across the country. In the film Sand Dollars (2015) directed by Laura Amelia Guzmán and Israel Cárdenas, Noelí (Janet Mojica), a young mulatto woman, altogether with her boyfriend (Ricardo Ariel Toribio), strips tourists of dollars and euro through prostitution. One of her frequent clients is Anne, a mature French woman (Geraldine Chaplin). While Noeli’s goal is to get all the euros she can, Anne falls in love with her and tries to bring her to France. Both the content of the film and its cinematographic languages are analyzed in light of theory of coloniality. This concept shows how European and American tourism, through the power of money, perpetuates colonial discourse, i. e., how race and ethnocentrism permeate cultural activities in their former colonies. Moreover, in the content analysis of the film the concepts of exchange value and fetishism are crucial to understanding how the colonial body becomes sexual commodity. They facilitate grasping the film’s inequity in terms of power in the relationship between the two women: the white old European woman and the young, poor, third-world mulatta. Even though the film attempts to break away from compulsory heterosexuality, the power relation between the two women persists due to the presence of the axis of race, ethnicity, age and gender. Both the novel Les dollars des sables written by Jean-Noel Pancrazi, and the film Sand Dollars offer an interesting insight into sex tourism and coloniality and shed additional light on the power relations between the former colonizers and its colonies.

Keywords: coloniality, ethnocentrism, exchange value, Europe, fetishism, money, power, prostitution, sex tourism, United States of America

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Authors: Alexander P. Vazhenin, Mikhail M. Lavrentiev, Alexey A. Romanenko, Pavel V. Tatarintsev

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One of the problems obstructing effective tsunami modelling is the lack of information about initial wave shape at source. The existing methods; geological, sea radars, satellite images, contain an important part of uncertainty. Therefore, direct measurement of tsunami waves obtained at the deep water bottom peruse recorders is also used. In this paper we propose a new method to reconstruct the initial sea surface displacement at tsunami source by the measured signal (marigram) approximation with the help of linear combination of synthetic marigrams from the selected set of unit sources, calculated in advance. This method has demonstrated good precision and very high performance. The mathematical model and results of numerical tests are here described.

Keywords: numerical tests, orthogonal decomposition, Tsunami Initial Sea Surface Displacement

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Authors: Ziwei Huang, Jian Ge, Jie Shen, Jiantao Weng

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Retrofitting of existing buildings plays a critical role to achieve sustainable development. This is being considered as one of the approaches to achieving sustainability in the built environment. In order to evaluate the different air-conditioning systems effectiveness and user satisfaction of the existing building which had transformed into green building effectively and accurately. This article takes the green office building in Zhejiang province, China as an example, analyzing the energy consumption, occupant satisfaction and indoor environment quality (IEQ) from the perspective of the thermal environment. This building is special because it combines ground source heat pump system and Variable Refrigerant Flow (VRF) air-conditioning system. Results showed that the ground source heat pump system(EUIa≈25.6) consumes more energy than VRF(EUIb≈23.8). In terms of a satisfaction survey, the use of the VRF air-conditioning was more satisfactory in temperature. However, the ground source heat pump is more satisfied in air quality.

Keywords: post-occupancy evaluation, green office building, air-conditioning systems, ground source heat pump system

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Authors: Marziyeh Heydari, Hossein Shokouhmand

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This article presents a numerical study of natural convection of a heat source embedded on the up wall of an enclosure filled with nanofluid. The bottom and vertical walls of the enclosure are maintained at a relatively low temperature. The type of nanofluid and solid volume fraction of nanoparticle on the heat transfer performance is studied. The results indicated that adding nanoparticle into pure paraffin improves heat transfer. The results are presented over a wide range of Rayleigh numbers(Ra=〖10〗^3 〖-10〗^5), the volume fraction of nanoparticles (0≤ɸ≤0.4%). For an enclosure, the Nusselt number of a cu-paraffin nanofluid was reduced by increasing the volume fraction of nanoparticles above 0.2%.

Keywords: nanofluid, heat transfer, heat source, enclosure

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Authors: Xinke Huang, Huan Wang, Lidong Guo, Changbin Ju, Runbiao Liu, Guoen Cao, Yibo Wang, Honghua Xu

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Grid connected photovoltaic (PV) power system is to be developed in the direction of large-scale, clustering. Large-scale PV generation systems connected to HVDC grid have many advantages compared to its counterpart of AC grid, and DC connection is the tendency. DC/DC converter as the most important device in the system, has become one of the hot spots recently. The paper proposes a Quasi Z-Source(QZS) based Boost Full Bridge Isolated DC/DC Converter(BFBIC) topology as a basis power module and combination through input parallel output series(IPOS) method to improve power capacity and output voltage to match with the HVDC grid. The topology has both traditional voltage source and current source advantages, it permit the H-bridge short through and open circuit, which adopt utility duty cycle control and achieved input current and output voltage balancing through input current sharing control strategy. A ±10kV/200kW system model is built in MATLAB/SIMULINK to verify the proposed topology and control strategy.

Keywords: PV Generation System, Cascaded DC/DC converter, HVDC, Quasi Z Source Converter

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Authors: Hui Hsin Huang

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The downstream manufactures will order their materials from different upstream suppliers to maintain a certain level of the demand. This paper proposes a bivariate model to portray this phenomenon of material demand. We use empirical data to estimate the parameters of model and evaluate the RMSD of model calibration. The results show that the model has better fitness.

Keywords: recency, ordering time, materials demand quantity, multi-source ordering

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Authors: Israt Jahan Eshita

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Flows developed between two parallel disks have many engineering applications. Two types of non-swirling flows can be generated in such a domain. One is purely source flow in disc type domain (outward flow). Other is purely sink flow in disc type domain (inward flow). This situation often appears in some turbo machinery components such as air bearings, heat exchanger, radial diffuser, vortex gyroscope, disc valves, and viscosity meters. The main goal of this paper is to show the mesh convergence, because mesh convergence saves time, and economical to run and increase the efficiency of modeling for both sink and source flow. Then flow field is resolved using a very fine mesh near-wall, using enhanced wall treatment. After that we are going to compare this flow using standard k-epsilon, RNG k-epsilon turbulence models. Lastly compare some experimental data with numerical solution for sink flow. The good agreement of numerical solution with the experimental works validates the current modeling.

Keywords: hydraulic diameter, k-epsilon model, meshes convergence, Reynolds number, RNG model, sink flow, source flow, wall y+

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Authors: Tooba Aslam, Efthalia Chatzisymeon

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Untreated Municipal Wastewater (MWW) is renowned as the utmost harmful pollution caused to environmental water due to the high presence of nutrients and organic contaminants. Removal of Chemical Oxygen Demand (COD) from synthetic as well as municipal wastewater is investigated by using acid mine drainage as a source of iron to initiate the solar photo-Fenton treatment of municipal wastewater. In this study, Acid Mine Drainage (AMD) and different minerals enriched in iron, such as goethite, hematite, magnetite, and magnesite, have been used as the source of iron to initiate the photo-Fenton process. Co-treatment of real municipal wastewater and acid mine drainage /minerals is widely examined. The effects of different parameters such as minerals recovery from AMD, AMD as a source of iron, H₂O₂ concentration, and COD concentrations on the COD percentage removal of the process are studied. The results show that, out of all the four minerals, only hematite (1g/L) could remove 30% of the pollutants at about 100 minutes and 1000 ppm of H₂O₂. The addition of AMD as a source of iron is performed and compared with both synthetic as well as real wastewater from South Africa under the same conditions, i.e., 1000 ppm of H₂O₂, ambient temperature, 2.8 pH, and solar simulator. In the case of synthetic wastewater, the maximum removal (56%) is achieved with 50 ppm of iron (AMD source) at 160 minutes. On the other hand, in real wastewater, the removal efficiency is 99% with 30 ppm of iron at 90 minutes and 96% with 50 ppm of iron at 120 minutes. In conclusion, overall, the co-treatment of AMD and MWW by solar photo-Fenton treatment appears to be an effective and promising method to remove organic materials from Municipal wastewater.

Keywords: municipal wastewater treatment, acid mine drainage, co-treatment, COD removal, solar photo-Fenton, circular economy

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Authors: Hamed Mohamed Haggag

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Prior to 12 November 1955, no earthquakes have been reported from the Abu Dabbab area in the International Seismological Center catalogue (ISC). The largest earthquake in Abu Dabbab area occurred on November 12, 1955 with magnitude Mb 6.0. The closest station from the epicenter was at Helwan (about 700 km to the north), so the depth of this event is not constrained and no foreshocks or aftershocks were recorded. Two other earthquakes of magnitude Mb 4.5 and 5.2 took place in the same area on March 02, 1982 and July 02, 1984, respectively. Since the installation of Aswan Seismic Network stations in 1982, (250-300 km to the south-west of Abu Dabbab area) then the Egyptian Natoinal Seismic Network stations, it was possible to record some activity from Abu Dabbab area. The recorded earthquakes at Abu Dabbab area as recorded from 1982 to 2014 shows that the earthquake epicenters are distributed in the same direction of the main trends of the faults in the area, which is parallel to the Red Sea coast. The spectral analysis was made for some earthquakes. The source parameters, seismic moment (Mo), source dimension (r), stress drop (Δδ), and apparent stress (δ) are determined for these events. The spectral analysis technique was completed using MAG software program.

Keywords: Abu Dabbab, seismicity, seismic moment, source parameter

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Authors: A. A. Embaby, A. Abu Halawa, M. Ramadan

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In Kingdom of Saudi Arabia, there are several areas where expansive soil exists in the form of variable-thicknesses layers in the developed regions. Severe distress to infrastructures can be caused by the development of heave and swelling pressure in this kind of expansive shale. Among the various techniques for expansive soil mitigation, the removal and replacement technique is very popular for lightly loaded structures and shallow foundations. This paper presents the result of an experimental study conducted for evaluating the effect of type and thickness of the cushion soils on mitigation of swelling characteristics of expanded shale. Seven undisturbed shale samples collected from Al Qadsiyah district, which is located in the Tabuk town north Kingdom of Saudi Arabia, are treated with two types of cushion coarse-grained sediments (CCS); sand and gravel. Each type is represented with three thicknesses, 22%, 33% and 44% in relation to the depth of the active zone. The test results indicated that the replacement of expansive shale by CCS reduces the swelling potential and pressure. It is found that the reduction in swelling depends on the type and thickness of CCS. The treatment by removing the original expansive shale and replacing it by cushion sand with 44% thickness reduced the swelling potential and pressure of about 53.29% and 62.78 %, respectively.

Keywords: cushion coarse-grained sediments (CCS), expansive soil, Saudi Arabia, swelling pressure, Tabuk Shale

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Authors: Evans Iyamu

Abstract:

Genes encoding hydrophobins play distinct roles at different stages of the life cycle of fungi, and they foster hyphal attachment to surfaces. The hydrophobin Sc4 is known to provide a hydrophobic membrane lining of the gas channels within Schizophyllum commune fruiting bodies. Here, we cultivated non-fruiting, monokaryotic S. commune 12-43 on glass surfaces that could be verified by micrography. Differential gene expression profiling of nine hydrophobin genes and the hydrophobin-like sc15 gene by quantitative PCR showed significant up-regulation of sc4 when S. commune was attached to glass surfaces, also confirmed with RNA-Seq data analysis. Another silicate, namely quartz sand, was investigated, and induction of sc4 was seen as well. The up-regulation of the hydrophobin gene sc4 may indicate involvement in S. commune hyphal attachment to glass as well as quartz surfaces. We propose that the covering of hyphae by Sc4 allows for direct interaction with the hydrophobic surfaces of silicates and that differential functions of specific hydrophobin genes depend on the surface interface involved. This study could help with the clarification of the biological functions of hydrophobins in natural surroundings, including hydrophobic surface attachment. Therefore, the analysis of growth on glass serves as a basis for understanding S. commune interaction with glass surfaces while providing the possibility to visualize the interaction microscopically.

Keywords: hydrophobin, structured glass surfaces, differential gene expression, quartz sand

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Authors: N. Deepika, P. A. L. Narayana

Abstract:

Linear stability analysis of double diffusive convection in a horizontal porous layer saturated with fluid is examined by considering the effects of viscous dissipation, concentration based internal heat source and vertical throughflow. The basic steady state solution for Governing equations is computed. Linear stability analysis has been implemented numerically by using Runge-kutta method. Critical thermal Rayleigh number Rac is obtained for various values of solutal Rayleigh number Sa, vertical Peclet number Pe, Gebhart number Ge, Lewis number Le and measure of concentration based internal heat source $\gamma$. It is observed that Ge has destabilizing effect for upward throughflow and stabilizing effect for downward throughflow. For sufficient value of Pe, $\gamma$ has considerable destabilizing effect for upward throughflow, insignificant destabilizing effect for downward throughflow.

Keywords: porous medium, concentration based internal heat source, vertical throughflow, viscous dissipation

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Authors: Asadollah Bahrami

Abstract:

In the present study, spectral radiative entropy generation is analyzed in a furnace filled with a mixture of H₂O, CO₂ and soot at radiative equilibrium. For the angular and spatial discretization of the radiative transfer equation and radiative entropy generation equations, the discrete ordinates method and the finite volume method are used, respectively. Spectral radiative properties are obtained using the correlated-k (CK) non-gray model with updated parameters based on the HITEMP2010 high-resolution database. In order to evaluate the effects of the location of the heat source, boundary condition and wall emissivity on radiative entropy generation, five cases are considered with different conditions. The spectral and total radiative entropy generation in the system are calculated for all cases and the effects of mentioned parameters on radiative entropy generation are attentively analyzed and finally, the optimum condition is especially presented. The most important results can be stated as follows: Results demonstrate that the wall emissivity has a considerable effect on the radiative entropy generation. Also, irreversible radiative transfer at the wall with lower temperatures is the main source of radiative entropy generation in the furnaces. In addition, the effect of the location of the heat source on total radiative entropy generation is less than other factors. Eventually, it can be said that characterizing the effective parameters of radiative entropy generation provides an approach to minimizing the radiative entropy generation and enhancing the furnace's performance practicality.

Keywords: spectral radiative entropy generation, non-gray medium, correlated k(CK) model, heat source

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Authors: Md. Golam Mostafa

Abstract:

This paper describes the use of Koha open source library management software for information management in university libraries of Bangladesh. Manual record keeping is a time-consuming and tedious task, which may lead to errors frequently. To maintain the quality of services, any organization needs to manage with the help of a computerized system. The advent of information technology paved the way for library computerization. This paper has provided a short history as well as the present ongoing development of the library computerization system in Bangladesh, which has developed as a library management software Koha on the basis of research and development. Koha integrated library systems (ILS) software is very user friendly open source software. It refers to software in which the source code is freely available for others to view, amend, and adapt. Koha integrated library systems maintained by and used by libraries all over the world. In this context, this paper will analyze Koha library management software, which proves appropriate for the present necessities of library management in Bangladesh. At last, result from the study has been analyzed using different tables and graphs.

Keywords: Koha Open Source Software, integrated library system, RFID facilities, university libraries, Bangladesh

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