Search results for: column removal scenario

Authors: Seo Soo-Yeon, Kim Sang-Ku, Noh Sang-Hyun, Lee Ji-Eun, Kim Seol-Ki, Lim Jong-Wook

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This paper presents a test result to find the structural capacity of Hollow-Precast Concrete (HPC) column with Head-Splice Sleeve (HSS) for the connection of bars under horizontal cyclic load. Two Half-scaled HPC column specimens were made with the consideration of construction process in site. The difference between the HPC specimens is the location of HSS for bar connection. The location of the first one is on the bottom slab or foundation while the other is above the bottom slab or foundation. Reinforced concrete (RC) column was also made for the comparison. In order to evaluate the hysteretic behavior of the specimens, horizontal cyclic load was applied to the top of specimen under constant axial load. From the test, it is confirmed that the HPC columns with HSS have enough structural capacity that can be emulated to RC column. This means that the HPC column with HSS can be used in the moment resisting frame system.

Keywords: structural capacity, hollow-precast concrete column, head-splice sleeve, horizontal cyclic load

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Authors: R. Ziaie Moayed, M. Hossein Zade

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Out of all methods for ground improvement, stone column became more popular these days due to its simple construction and economic consideration. Installation of stone column especially in loose fine graded soil causes increasing in load bearing capacity and settlement reduction. Encased granular stone columns (EGCs) are commonly subjected to vertical load. However, they may also be subjected to significant amount of shear loading. In this study, three-dimensional finite element (FE) analyses were conducted to estimate the shear load capacity of EGCs in sandy soil. Two types of different cases, stone column and geosynthetic encased stone column were studied at different normal pressures varying from 15 kPa to 75 kPa. Also, the effect of diameter in two cases was considered. A close agreement between the experimental and numerical curves of shear stress - horizontal displacement trend line is observed. The obtained result showed that, by increasing the normal pressure and diameter of stone column, higher shear strength is mobilized by soil; however, in the case of encased stone column, increasing the diameter had more dominated effect in mobilized shear strength.

Keywords: encased stone column, laterally load, ordinary stone column, validation

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Authors: Dan Qu, Dezhi Sun, Benhang Li

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The removal of Nitenpyram from farmland runoff by an integrated eco-ditches and constructed wetland system was investigated in the case of different HRT. Experimental results show that the removal of COD, N and P was not influenced by the Nitenpyram. When the HRT was 2.5 d, 2 d, and 1 d, the Nitenpyram removal efficiency could reach 100%, 100% and 84%, respectively. The removal efficiency in the ecological ditches was about 38%-40% in the case of different HRT, while that in the constructed wetland was influenced by the HRT variation. The optimum HRT for Nitenpyram and pollutants removal was 2 d. The substrate zeolite with soil and hollow brick layer enabled higher Nitenpyram removal rates, probably due to the cooperative phenomenon of plant uptake and microbiological deterioration as well as the adsorption by the substrate.

Keywords: ecological ditch, vertical flow constructed wetland, hydraulic retention time, Nitenpyram

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Authors: Abubakar Danbaba

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Sudoku squares have been widely used to design an experiment where each treatment occurs exactly once in each row, column or sub-block. For some experiments, the size of row (or column or sub-block) may be larger than the number of treatments. Since each treatment appears only once in each row (column or sub-block) with an additional empty cell such designs are partially balanced Sudoku designs (PBSD) with NP-complete structures. This paper proposed methods for constructing PBSD of prime order of treatments by a modified Kronecker product and swap of matrix row (or column) in cyclic order. In addition, linear model and procedure for the analysis of data for PBSD are proposed.

Keywords: sudoku design, partial sudoku, NP-complete, Kronecker product, row and column swap

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Authors: Pascal Mwenge, Tumisang Seodigeng

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The increase in urbanisation in South Africa has led to an increase in water demand and a decline in freshwater supply. Despite this, poor water usage is still a major challenge in South Africa, for instance, freshwater is still used for non-drinking applications. The freshwater shortage can be alleviated by using other sources of water for non-portable purposes such as greywater treated with activated biochar produced from agricultural waste. The success of activated biochar produced from agricultural waste to treat greywater can be both economically and environmentally beneficial. Greywater treated with activated biochar produced from agricultural waste is considered a cost-effective wastewater treatment.  This work was aimed at determining the ability of activated biochar to remove Total Suspended Solids (TSS), Ammonium (NH₄-N), Nitrate (NO₃-N), and Chemical Oxygen Demand (COD) from greywater. The experiments were carried out in 800 ml laboratory plastic cylinders used as filter columns. 2.5 cm layer of gravel was used at the bottom and top of the column to sandwich the activated biochar material. Activated biochar (200 g and 400 g) was loaded in a column and used as a filter medium for greywater. Samples were collected after a week and sent for analysis. Four types of greywater were treated: Kitchen, floor cleaning water, shower and laundry water. The findings showed: 95% removal of TSS, 76% of NO₃-N and 63% of COD on kitchen greywater and 85% removal of NH₄-N on bathroom greywater, as highest removal of efficiency of the studied pollutants. The results showed that activated biochar produced from agricultural waste reduces a certain amount of pollutants from greywater. The results also indicated the ability of activated biochar to treat greywater for onsite non-potable reuse purposes.

Keywords: activated biochar produced from agriculture waste, ammonium, NH₄-N, chemical oxygen demand, COD, greywater, nitrate, NO₃-N, total suspended solids, TSS

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Authors: Rabab Allouzi, Amer Alkloub

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As the complex shaped buildings become a popular trend for architects, this paper is presented to investigate the performance of reinforced concrete flat plate-inclined column connection. The studies on the inclined column and flat plate connections are not sufficient in comparison to those on the conventional structures. The effect of column angle of inclination on the punching shear strength is found significant and studied herein. This paper presents a non-linear finite element based modeling approach to estimate behavior of RC flat plate inclined column connection. Results from simulations of RC flat plate-straight column connection show good agreement with experimental response of specimens tested by other researchers. The model is further used to study the response of inclined columns to punching at various ranges of inclination angles. The inclination angle can be included in the punching shear strength provisions provided by ACI 318-14 to account for the effect of column inclination.

Keywords: punching shear, non-linear finite element, inclined columns, reinforced concrete connection

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Authors: A. Ghribi, M. Bagane

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The discharge of dye in industrial effluents is of great concern because their presence and accumulation have a toxic or carcinogenic effect on living species. The removals of such compounds at such low levels are a difficult problem. Physicochemical technique such as coagulation, flocculation, ozonation, reverse osmosis and adsorption on activated carbon, manganese oxide, silica gel and clay are among the methods employed. The adsorption process is an effective and attractive proposition for the treatment of dye contaminated wastewater. Activated carbon adsorption in fixed beds is a very common technology in the treatment of water and especially in processes of decolouration. However, it is expensive and the powdered one is difficult to be separated from aquatic system when it becomes exhausted or the effluent reaches the maximum allowable discharge level. The regeneration of exhausted activated carbon by chemical and thermal procedure is also expensive and results in loss of the sorbent. Dye molecules also have very high affinity for clay surfaces and are readily adsorbed when added to clay suspension. The elimination of the organic dye by clay was studied by serval researchers. The focus of this research was to evaluate the adsorption potential of the raw clay in removing congo red from aqueous solutions using a laboratory fixed-bed column. The continuous sorption process was conducted in this study in order to simulate industrial conditions. The effect of process parameters, such as inlet flow rate, adsorbent bed height and initial adsorbate concentration on the shape of breakthrough curves was investigated. A glass column with an internal diameter of 1.5 cm and height of 30 cm was used as a fixed-bed column. The pH of feed solution was set at 7.Experiments were carried out at different bed heights (5-20 cm), influent flow rates (1.6- 8 mL/min) and influent congo red concentrations (10-50 mg/L). The obtained results showed that the adsorption capacity increases with the bed depth and the initial concentration and it decreases at higher flow rate. The column regeneration was possible for four adsorption–desorption cycles. The clay column study states the value of the excellent adsorption capacity for the removal of congo red from aqueous solution. Uptake of congo red through a fixed-bed column was dependent on the bed depth, influent congo red concentration and flow rate.

Keywords: adsorption, breakthrough curve, clay, congo red, fixed bed column, regeneration

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Authors: Abdul Hakim Chikho

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Calculating the ultimate load of a column in a sway framed structure involves, in the currently used design method, the calculation of the column effective length and utilizing the interaction formulas or tables. Therefore, no allowance is usually made for the effects of the presence of semi rigid connections or the presence of infill panels. In this paper, a new and simple design procedure is recommend to calculate the ultimate load of a framed Column allowing for the presence of rotational end restraints, semi rigid connections, the column end moments resulted from the applied vertical and horizontal loading and infill panels in real steel structure. In order to verify the accuracy of the recommended method to predict good and safe estimations of framed column ultimate loads, several examples have been solved utilizing the recommended procedure, and the results were compared to those obtained using a second order computer program, and good correlation had been obtained. Therefore, the accuracy of the proposed method to predict the Behaviour of practical steel columns in framed structures has been verified.

Keywords: column ultimate load, semi rigid connections, steel column, infill panel, steel structure

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Authors: Walid El Kamash

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Sand columns (or granular piles) can be employed as soil strengthening for flexible constructions such as road embankments, oil storage tanks in addition to multistory structures. The challenge of embedding the sand columns in soft soil is that the surrounding soft soil cannot avail the enough confinement stress in order to keep the form of the sand column. Therefore, the sand columns which were installed in such soil will lose their ability to perform needed load-bearing capacity. The encasement, besides increasing the strength and stiffness of the sand column, prevents the lateral squeezing of sands when the column is installed even in extremely soft soils, thus enabling quicker and more economical installation. This paper investigates the improvement in load capacity of the sand column by encasement through a comprehensive parametric study using the 3-D finite difference analysis for the soft clay of soil in Egypt. Moreover, the study was extended to include a comparison study between encased sand column and Deep Mixed columns (DM). The study showed that confining the sand by geosynthetic resulted in an increment of shear strength. That result paid the attention to use encased sand stone rather than deep mixed columns due to relative high permeability of the first material.

Keywords: encased sand column, Deep mixed column, numerical analysis, improving soft soil

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Authors: Rifqi Irvansyah, Abdullah Abdullah, Yunita Idris, Bunga Raihanda

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Banda Aceh is particularly susceptible to heightened vulnerability during natural disasters due to its concentrated exposure to multi-hazard risks. Despite urgent priorities during the aftermath of natural disasters, such as the 2004 Indian Ocean earthquake and tsunami, several public facilities, including school buildings, sustained damage yet continued operations without adequate repairs, even though they were submerged by the tsunami. This research aims to evaluate the consequences of column damage induced by tsunami inundation on the structural integrity of buildings. The investigation employs interaction diagrams for columns to assess their capacity, taking into account factors such as rebar deterioration and corrosion. The analysis result shows that one-fourth of the K1 columns on the first floor fall outside of the column interaction diagram, indicating that the column structure cannot handle the load above it, as evidenced by the presence of Pu and Mu, which are greater than the column's design strength. This suggests that the five columns of K1 should be cause for concern, as the column's capacity is decreasing. These results indicate that the structure of the building cannot sustain the applied load because the column cross-section has deteriorated. In contrast, all K2 columns meet the design strength, indicating that the column structure can withstand the structural loads.

Keywords: tsunami inundation, column damage, column interaction diagram, mitigation effort

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Authors: Omar M. Ben-Sasi

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Ductility of slab-column connections of flat slab structures is a desirable property that should be considered when designing such connections which are susceptible to punching failure around their columns. Tests to failure on six half-scale specimens were conducted for slab-interior column connections transferring shear force and unbalanced moment. The influences on connection ductility of four parameters; namely, the moment to shear force ratio, the ratio of column side length to slab effective depth, the aspect ratio of the column cross section, and the presence of four square openings located next to column corners were investigated. The study revealed marked effects of these parameters on connection ductility. Increasing the first and second parameters, were found to be in favor of increasing connection ductility, while the third and fourth parameters were found to have negative effects on the connection ductility. These findings should, hopefully, help in designing interior connections of flat slab structures.

Keywords: ductility, flat slab, failure, shear force, moment, unbalanced moment, punching failure, connection, interior-column connection

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Authors: Alex Maina, Mwenda Makathimo, Adwek George, Charles Opiyo

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This research entails the simulation of three possible power scenarios for Kenya from 2015 to 2035 using the Low Emissions Analysis Platform (LEAP). These scenarios represent the unfolding future electricity generation that will fully satisfy the demand while considering the following: energy security, power generation cost and impacts on the environment. These scenarios are Reference Scenario (RS), Nuclear Scenario (NS) and More Renewable Scenario (MRS). The findings obtained reveals that the most sustainable scenario while comparing the costs was found to be the coal scenario with a Net Present Value (NPV) of $30,052.67 million though it has the highest Green House Gases (GHGs) emissions. However, the More Renewable Scenario (MRS) had the least GHGs emissions but was found to be a most expensive scenario to implement with an NPV of $30,733.07 million.

Keywords: energy security, Kenya, low emissions analysis platform, net-present value, greenhouse gases

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Authors: L. Pavithra, R. Sharmila, Shivani Sridhar

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Columns severe structural damage needs proportioning a significant portion of earthquake energy can be dissipated yielding in the beams. Presence of axial load along with cyclic loading has a significant influence on column. The objective of this paper is to present the analytical results of columns subjected to biaxial cyclic loading.

Keywords: RC column, Seismic behaviour, cyclic behaviour, biaxial testing, ductile behaviour

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Authors: H. Shiu, M.S. Lu, Y.P. Tsai

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This study explored the impacts of CuO, TiO2, SiO2 nanoparticles on biological phosphorus removal. Experimental results showed that the phosphorus removal ability of phosphorus accumulating organism (PAO) was initially inhibited when CuO nanoparticle concentration was 5 mgl-1. The inhibition of phosphorus removal for 1000 mgl-1 of TiO2 with sunlight was higher than without sunlight case. The inhibition of phosphorus removal began at 500 mgl-1 SiO2 nanoparticle concentration. Inhibition became apparent when SiO2 nanoparticle concentration was up to 1000 mgl-1.

Keywords: nano copper oxide, nano titanium dioxide, nano silica, enhanced biological phosphate removal

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Authors: P. Lestinsky, D. Jecha, V. Brummer, P. Stehlik

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Scrubbing by a liquid spraying is one of the most effective processes used for removal of fine particles and soluble gas pollutants (such as SO2, HCl, HF) from the flue gas. There are many configurations of scrubbers designed to provide contact between the liquid and gas stream for effectively capturing particles or soluble gas pollutants, such as spray plates, packed bed towers, jet scrubbers, cyclones, vortex and venturi scrubbers. The primary function of venturi scrubber is the capture of fine particles as well as HCl, HF or SO2 removal with effect of the flue gas temperature decrease before input to the absorption column. In this paper, sulfur dioxide (SO2) from flue gas was captured using new design replacing venturi scrubber (1st degree of wet scrubbing). The flue gas was prepared by the combustion of the carbon disulfide solution in toluene (1:1 vol.) in the flame in the reactor. Such prepared flue gas with temperature around 150 °C was processed in designed laboratory O-element scrubber. Water was used as absorbent liquid. The efficiency of SO2 removal, pressure drop and temperature drop were measured on our experimental device. The dependence of these variables on liquid-gas ratio was observed. The average temperature drop was in the range from 150 °C to 40 °C. The pressure drop was increased with increasing of a liquid-gas ratio, but not as much as for the common venturi scrubber designs. The efficiency of SO2 removal was up to 70 %. The pressure drop of our new designed wet scrubber is similar to commonly used venturi scrubbers; nevertheless the influence of amount of the liquid on pressure drop is not so significant.

Keywords: desulphurization, absorption, flue gas, modeling

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Authors: Muneerah Jeludin

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The vibrated column has been widely used over the last three decades to improve the performance of soft ground and engineered compacted fill. The main reason for adopting this technique is that it is economically viable and environmental friendly. The performance of granular column with regards to bearing capacity has been well documented; however, information regarding the settlement behavior of granular columns is still limited. This paper aims to address the findings from a laboratory model study in terms of its settlement improvement. A 300 mm diameter and 400 mm high kaolin clay model was used in this investigation. Columns of various heights were installed in the clay bed using replacement method. The results in relation to load sharing mechanism between the column and surrounding clay just under the footing indicated that in short column, the available shaft resistance was not significant and introduces a potential for end braing failure as opposed to bulging failure in long columns. The settlement improvement factor corroborates well with field observations.

Keywords: ground improvement, model test, reinforced soil, foundation

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Authors: M. Abd elfattah, M. Ossman, Nahla A. Taha

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The present work explored the use of Egyptian rice straw, an agricultural waste that leads to global warming problem through brown cloud, as a potential feedstock for the preparation of activated carbon by physical and chemical activation. The results of this study showed that it is feasible to prepare activated carbons with relatively high surface areas and pore volumes from the Egyptian rice straw by direct chemical and physical activation. The produced activated carbon from the two methods (AC1 and AC2) could be used as potential adsorbent for the removal of Fe(III) from aqueous solution contains heavy metals and polluted water. The adsorption of Fe(III) was depended on the pH of the solution. The optimal Fe(III) removal efficiency occurs at pH 5. Based on the results, the optimum contact time is 60 minutes and adsorbent dosage is 3 g/L. The adsorption breakthrough curves obtained at different bed depths indicated increase of breakthrough time with increase in bed depths. A rise in inlet Fe(III) concentration reduces the throughput volume before the packed bed gets saturated. AC1 showed higher affinity for Fe(III) as compared to Raw rice husk.

Keywords: rice straw, activated carbon, Fe(III), fixed bed column, pyrolysis

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Authors: Hansoo Kim, Seunghak Shin

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The differential column shortening in tall buildings can be reduced by improving material and structural characteristics of the structural systems. This paper proposes structural methods to reduce differential column shortening in reinforced concrete tall buildings; connecting columns with rigidly jointed horizontal members, using outriggers, and placing additional reinforcement at the columns. The rigidly connected horizontal members including outriggers reduce the differential shortening between adjacent vertical members. The axial stiffness of columns with greater shortening can be effectively increased by placing additional reinforcement at the columns, thus the differential column shortening can be reduced in the design stage. The optimum distribution of additional reinforcement can be determined by applying a gradient based optimization technique.

Keywords: column shortening, long-term behavior, optimization, tall building

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Authors: Soheil Tavakolpour

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Enhance Oil Recovery (EOR) can be considered as an undeniable action in reservoirs life period. Different kind of EOR methods are available, but suitable EOR method depends on reservoir properties, like rock and fluid properties. In this paper, we nominated fifth SPE’s Comparative Solution Projects (CSP) for testing different scenarios. We used seven EOR scenarios for this reservoir and we simulated it for 10 years after 2 years production without any injection. The first scenario is waterflooding for whole of the 10 years period. The second scenario is gas injection for ten years. The third scenario is Water-Alternation-Gas (WAG). In the next scenario, water injected for 4 years before starting WAG injection for the next 6 years. In the fifth scenario, water injected after 6 years WAG injection for 4 years. For sixth and last scenarios, all the things are similar to fourth and fifth scenarios, but gas injected instead of water. Results show that fourth scenario was the most efficient method for 10 years EOR, but it resulted very high water production. Fifth scenario was efficient too, with little water production in comparison to the fourth scenario. Gas injection was not economically attractive. In addition to high gas production, it produced less oil in comparison to other scenarios.

Keywords: WAG, SPE’s comparative solution projects, numerical simulation, EOR scenarios

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Authors: Junior B. N. Adohinzin, Ling Xu

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Nitrogen is among the main nutrients encouraging the growth of organic matter and algae which cause eutrophication in water bodies. Therefore, its removal from wastewater has become a worldwide emerging concern. In this research, an innovative Membrane Bioreactor (MBR) system named “moving bed membrane bioreactor (MBMBR)” was developed and investigated under intermittently-aerated mode for simultaneous removal of organic carbon and nitrogen. Results indicated that the variation of the intermittently aerated duration did not have an apparent impact on COD and NH4+–N removal rate, yielding the effluent with average COD and NH4+–N removal efficiency of more than 92 and 91% respectively. However, in the intermittently aerated cycle of (continuously aeration/0s mix), (aeration 90s/mix 90s) and (aeration 90s/mix 180s); the average TN removal efficiency was 67.6%, 69.5% and 87.8% respectively. At the same time, their nitrite accumulation rate was 4.5%, 49.1% and 79.4% respectively. These results indicate that the intermittently aerated mode is an efficient way to controlling the nitrification to stop at nitrition; and also the length of anoxic duration is a key factor in improving TN removal.

Keywords: membrane bioreactor (MBR), moving bed biofilm reactor (MBBR), nutrients removal, simultaneous nitrification and denitrification

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Authors: Y. T. Lee, J. H. Na, S. H. Kim, S. U. Hong

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In this study, an experimental research for estimation of slab depth, column size and location of rebar of concrete specimen is conducted using the Impact Echo Method (IE) based on stress wave among non-destructive test methods. Estimation of slab depth had total length of 1800×300 and 6 different depths including 150 mm, 180 mm, 210 mm, 240 mm, 270 mm and 300 mm. The concrete column specimen was manufactured by differentiating the size into 300×300×300 mm, 400×400×400 mm and 500×500×500 mm. In case of the specimen for estimation of rebar, rebar of ∅22 mm was used in a specimen of 300×370×200 and arranged at 130 mm and 150 mm from the top to the rebar top. As a result of error rate of slab depth was overall mean of 3.1%. Error rate of column size was overall mean of 1.7%. Mean error rate of rebar location was 1.72% for top, 1.19% for bottom and 1.5% for overall mean showing relative accuracy.

Keywords: impact echo method, estimation, slab depth, column size, rebar location, concrete

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Authors: Pham-Thi Huong, Byeong-Kyu Lee, Chi-Hyeon Lee, JiTae Kim

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This study analyzed the removal of p-nitrophenol from wastewater using Fe-nano zeolite synthesized. The basic physical-chemical properties of Fe-nano zeolite was determined by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy. We focus on finding out the optimum conditions in adsorption and desorption processes for removal of p-nitrophenol by using Fe-nano zeolite in wastewater. The optimum pH for p-nitrophenol removal in wastewater was 5.0. Adsorption isotherms were better fitted with the Langmuir isotherm than with the Freundlich with 165.58 mg/g adsorption capacity of p-nitrophenol. These findings support potential of Fe-nano zeolite as an effective adsorbent for p-nitrophenol removal from wastewater.

Keywords: Fe-nano zeolite, adsorption, wastewater, regeneration

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Authors: Xavier A. Conlan

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Speed of analysis is a significant limitation to current high-performance liquid chromatography/mass spectrometry (HPLC/MS) and ultra-high-pressure liquid chromatography (UHPLC)/MS systems both of which are used in many forensic investigations. The flow rate limitations of MS detection require a compromise in the chromatographic flow rate, which in turn reduces throughput, and when using modern columns, a reduction in separation efficiency. Commonly, this restriction is combated through the post-column splitting of flow prior to entry into the mass spectrometer. However, this results in a loss of sensitivity and a loss in efficiency due to the post-extra column dead volume. A new chromatographic column format known as 'parallel segmented flow' involves the splitting of eluent flow within the column outlet end fitting, and in this study we present its application in order to interrogate the provenience of methamphetamine samples with mass spectrometry detection. Using parallel segmented flow, column flow rates as high as 3 mL/min were employed in the analysis of amino acids without post-column splitting to the mass spectrometer. Furthermore, when parallel segmented flow chromatography columns were employed, the sensitivity was more than twice that of conventional systems with post-column splitting when the same volume of mobile phase was passed through the detector. These finding suggest that this type of column technology will particularly enhance the capabilities of modern LC/MS enabling both high-throughput and sensitive mass spectral detection.

Keywords: chromatography, mass spectrometry methamphetamine, parallel segmented outlet flow column, forensic sciences

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Authors: Jerina Majeed, Jayshree Ramkumar, S. Chandramouleeswaran, A. K. Tyagi

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Removal of various toxic species from aqueous streams is of great importance. Sorption is one of the important remediation procedures as it involves the use of cheap and easily available materials. Also the advantage of regeneration of the sorbent involves the possibility of using novel sorbents. Nanosorbents are very important as the removal is based on the surface phenomena and this is greatly affected by surface charge and area. Functionalization has been very important to bring about the removal of metal ions with greater selectivity.

Keywords: mercury, lead, thiol functionalization, ZnO NPs

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Authors: Khalifa Kherafa

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This east project consists in studying beam–column joints concrete subjected to seismic loads. A bibliographical study was introduced to clarify the work undertaken by the researchers in the field during the three last decades and especially the two last year’s results which were to study for the determination of the method of calculating of transverse reinforcement in the various nodes of a structure. For application, the efforts in the posts el the beams of a building in R+4 in zone 3 were calculate according to the finite element method through the software .

Keywords: beam–column joints, cyclic loading, shearing force, damaged joint

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Authors: Ihsanullah, Muataz Ali Atieh

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In this study, a low-cost adsorbent carbon fly ash (CFA) was used for the removal of Phenol from the water. The adsorbent characteristics were observed by the Thermogravimetric Analysis (TGA), BET specific surface area analyzer, Zeta Potential and Field Emission Scanning Electron Microscopy (FE-SEM). The effect of pH, agitation speed, contact time, adsorbent dosage, and initial concentration of phenol were studied on the removal of phenol from the water. The optimum values of these variables for maximum removal of phenol were also determined. Both Freundlich and Langmuir isotherm models were successfully applied to describe the experimental data. Results showed that low-cost adsorbent phenol can be successfully applied for the removal of Phenol from the water.

Keywords: phenol, fly ash, adsorption, carbon adsorbents

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Authors: Sumi Deka, Krishna Gopal Bhattacharyya

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This paper evaluate the industrial use of Kala Jamun (Syzygiumcumini L.) Seed powder (KSP) for the continuous adsorption of Cr(VI) in a column adsorption process. Adsorption of Cr(VI) onto Kala jamun (Syzygiumcumini L.) Seed Powder have been examined with the variation of (a) bed depth of the adsorbents, (b) flow rate of the adsorbents and (c) Cr(VI) concentration. The results showed that both the adsorption and the regeneration of the Cr(VI) onto Kala Jamun (Syzygiumcumini L.) seed Powder (KSP) can effectively occur in the column mode of adsorption. On increasing the bed depth, the adsorption of Cr(VI) onto KSP increases whereas on increasing the flow rate and the Cr(VI) concentration of KSP adsorption decreases. The results of the column studies were also fitted to Bed Depth Service Time (BDST) model. The BDST model was appropriate for designing the column for industrial purpose.

Keywords: bed-depth-service-time, continuous adsorption, Cr(VI), KSP

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Authors: G. Anusha, J. Raja Murugadoss

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In recent years, the problem of water contaminant is drastically increasing due to the disposal of industrial wastewater containing iron, fluoride, mercury, lead, cadmium, phosphorus, silver etc. into water bodies. The non-biodegradable heavy metals could accumulate in the human system through food chain and cause various dreadful diseases and permanent disabilities and in worst cases it leads to casual losses. Further, the presence of the excess quantity of such heavy metals viz. Lead, Cadmium, Chromium, Nickel, Zinc, Copper, Iron etc. seriously affect the natural quality of potable water and necessitates the treatment process for removal. Though there are dozens of standard procedures available for the removal of heavy metals, their cost keeps the industrialists away from adopting such technologies. In the present work, an attempt has been made to remove such contaminants particularly fluoride and to study the efficiency of the removal of fluoride by adsorption using a new agro-based materials namely Limonia acidissima and Emblica officinalis which is commonly referred as wood apple and gooseberry respectively. Accordingly a set of experiments has been conducted using batch and column processes, with the help of activated carbon prepared from the shell of wood apple and seeds of gooseberries. Experiments reveal that the adsorption capacity of the shell of wood apple is significant to yield promising solutions.

Keywords: adsorption, fluoride, agro-based waste materials, Limonia acidissima, Emblica officinalis

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Authors: Nina N. Serdar, Jelena R. Pejović

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This paper presents seismic risk assessment of two bridge structure, based on the probabilistic performance-based seismic assessment methodology. Both investigated bridges are tree span continuous RC curved bridges with the difference in column shapes. First bridge (type A) has a wall-type pier and second (type B) has a two-column bent with circular columns. Bridges are designed according to European standards: EN 1991-2, EN1992-1-1 and EN 1998-2. Aim of the performed analysis is to compare seismic behavior of these two structures and to detect the influence of column shapes on the seismic response. Seismic risk assessment is carried out by obtaining demand fragility curves. Non-linear model was constructed and time-history analysis was performed using thirty five pairs of horizontal ground motions selected to match site specific hazard. In performance based analysis, peak column drift ratio (CDR) was selected as engineering demand parameter (EDP). For seismic intensity measure (IM) spectral displacement was selected. Demand fragility curves that give probability of exceedance of certain value for chosen EDP were constructed and based on them conclusions were made.

Keywords: RC curved bridge, demand fragility curve, wall type column, nonlinear time-history analysis, circular column

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Authors: Kartikaningsih Danis, Yao-Hui Huang

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Various techniques including conventional and advanced have been employed for the boron treatment from water and wastewater. The electrocoagulation involves an electrolytic reactor for coagulation/flotation with aluminium as anode and cathode. There is aluminium as coagulant to be used for removal which may induce secondary pollution in chemical coagulation. The purpose of this study is to investigate and compare the performance between electrocoagulation and chemical coagulation on boron removal from synthetic wastewater. The effect of different parameters, such as pH reaction, coagulant dosage, and initial boron concentration were examined. The results show that the boron removal using chemical coagulation was lower. At the optimum condition (e.g. pH 8 and 0.8 mol coagulant dosage), boron removal efficiencies for chemical coagulation and electrocoagulation were 61% and 91%, respectively. In addition, the electrocoagulation needs no chemical reagents and makes the boron treatment easy for application.

Keywords: boron removal, chemical coagulation, aluminum, electro-coagulation

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