Search results for: clover solution

Authors: Ayat N. El-Shazly, Dina Magdy Abdo, Hamdy Maamoun Abdel-Ghafar, Xiangju Song, Heqing Jiang

Abstract:

Product water recovery and draw solution (DS) reuse is the most energy-intensive stage in forwarding osmosis (FO) technology. Sucrose solution is the most suitable DS for FO application in food and beverages. However, sucrose DS recovery by conventional pressure-driven or thermal-driven concentration techniques consumes high energy. Herein, we developed a spontaneous and sustainable solar-driven evaporation process based on a photothermal membrane for the concentration and recovery of sucrose solution. The photothermal membrane is composed of multi-walled carbon nanotubes (f-MWCNTs)photothermal layer on a hydrophilic polyvinylidene fluoride (PVDF) substrate. The f-MWCNTs photothermal layer with a rough surface and interconnected network structures not only improves the light-harvesting and light-to-heat conversion performance but also facilitates the transport of water molecules. The hydrophilic PVDF substrate can promote the rapid transport of water for adequate water supply to the photothermal layer. As a result, the optimized f-MWCNTs/PVDF photothermal membrane exhibits an excellent light absorption of 95%, and a high surface temperature of 74 °C at 1 kW m−2 . Besides, it realizes an evaporation rate of 1.17 kg m−2 h−1 for 5% (w/v) of sucrose solution, which is about 5 times higher than that of the natural evaporation. The designed photothermal evaporation process is capable of concentrating sucrose solution efficiently from 5% to 75% (w/v), which has great potential in FO process and juice concentration.

Keywords: solar, pothothermal, membrane, MWCNT

Procedia PDF Downloads 60

Authors: Sen Yung Lee, Chih Cheng Huang, Te Wen Tu

Abstract:

A solution methodology without using integral transformation is proposed to develop analytical solutions for transient heat conduction in nonuniform hollow cylinders with time-dependent boundary condition at the outer surface. It is shown that if the thermal conductivity and the specific heat of the medium are in arbitrary polynomial function forms, the closed solutions of the system can be developed. The influence of physical properties on the temperature distribution of the system is studied. A numerical example is given to illustrate the efficiency and the accuracy of the solution methodology.

Keywords: analytical solution, nonuniform hollow cylinder, time-dependent boundary condition, transient heat conduction

Procedia PDF Downloads 472

Authors: M. Al Nur, M. S. Kaiser

Abstract:

Corrosion behaviour of hypereutectic Al-19Si automotive alloy in different pH=1, 3, 5, 7, 9, 11, and 13 environments was carried out using conventional gravimetric measurements and was complemented by resistivity, optical micrograph, scanning electron microscopy (SEM) and X-ray analyzer (EDX) investigations. Gravimetric analysis confirmed that the highest corrosion rate is shown at pH 13 followed by pH 1. Minimum corrosion occurs in the pH range of 3.0 to 11 due to establishment of passive layer on the surface. The highest corrosion rate at pH 13 is due to the presence of sodium hydroxide in the solution which dissolves the surface oxide film at a steady rate. At pH 1, it can be attributed that the presence of aggressive chloride ions serves to pick up the damage of the passive films at localized regions. With varying exposure periods by both, the environment complies with the normal corrosion rate profile that is an initial steep rise followed by a nearly constant value of corrosion rate. Resistivity increases in case of pH 1 solution for the higher pit formation and decreases at pH 13 due to formation of thin film. The SEM image of corroded samples immersed in pH 1 solution clearly shows pores on the surface and in pH 13 solution, and the corrosion layer seems more compact and homogenous and not porous.

Keywords: Al-Si alloy, corrosion, pH, resistivity, scanning electron microscopy (SEM)

Procedia PDF Downloads 137

Authors: Roli Saini, Pradeep Kumar

Abstract:

A coagulation/flocculation process was adopted for the reduction of carbamate insecticide (carbofuran) from aqueous solution. Ferric chloride (FeCl₃) was used as a coagulant to treat the carbofuran. To exploit the reduction efficiency of pesticide concentration and COD, the jar-test experiments were carried out and process was optimized through response surface methodology (RSM). The effects of two independent factors; i.e., FeCl₃ dosage and pH on the reduction efficiency were estimated by using central composite design (CCD). The initial COD of the 30 mg/L concentrated solution was found to be 510 mg/L. Results exposed that the maximum reduction occurred at an optimal condition of FeCl₃ = 80 mg/L, and pH = 5.0, from which the reduction of concentration and COD 75.13% and 65.34%, respectively. The present study also predicted that the obtained regression equations could be helpful as the theoretical basis for the coagulation process of pesticide wastewater.

Keywords: carbofuran, coagulation, optimization, response surface methodology

Procedia PDF Downloads 289

Authors: S. Vasailor, C. Rattanakawin

Abstract:

Electro-winning of copper metal from dilute sulfate solution (13.7 g/L) was performed in a lab electrolytic cell with stainless-steel cathode and lead-alloy anode. The effects of various parameters including cell voltage, electro-winning temperature and time were studied in order to acquire an appropriate current efficiency of copper deposition. The highest efficiency is about 95% obtaining from electro-winning condition of 3V, 55°C and 3,600 s correspondingly. The cathode copper with 95.5% Cu analyzed using atomic absorption spectrometry can be obtained from this single-winning condition. In order to increase the copper grade, solvent extraction should be used to increase the sulfate concentration, say 50 g/L, prior to winning the cathode copper effectively.

Keywords: copper metal, current efficiency, dilute sulfate solution, electro-winning

Procedia PDF Downloads 112

Authors: M. S. Ashraf, Raja Rizwan Hussain, A. M. Alhozaimy, A. I. Al-Negheimish

Abstract:

The effect of supplementary cementitious materials (SCMs) with concrete pore solution on the protective properties of the oxide films that form on reinforcing steel bars has been experimentally investigated using electrochemical impedance spectroscopy (EIS) and Tafel Scan. The tests were conducted on oxide films grown in saturated calcium hydroxide solutions that included different representative amounts of NaOH and KOH which are the compounds commonly observed in ordinary portland cement concrete pore solution. In addition to that, commonly used mineral admixtures (silica fume, natural pozzolan and fly ash) were also added to the simulated concrete pore solution. The results of electrochemical tests show that supplementary cementitious materials do have an effect on the protective properties of the passive oxide film. In particular, silica fume has been shown to have a negative influence on the film quality though it has positive effect on the concrete properties. Fly ash and natural pozzolan increase the protective qualities of the passive film. The research data in this area is very limited in the past and needed further investigation.

Keywords: supplementary cementitious materials (SCMs), passive film, EIS, Tafel scan, rebar, concrete, simulated concrete pore solution (SPS)

Procedia PDF Downloads 371

Authors: A. Amiri Delouei

Abstract:

In the current study, two-dimensional unsteady heat conduction in a functionally graded cylinder is studied analytically. The temperature distribution is in radial and longitudinal directions. Heat conduction coefficients are considered a power function of radius both in radial and longitudinal directions. The proposed solution can exactly satisfy the boundary conditions. Analytical unsteady temperature distribution for different parameters of functionally graded cylinder is investigated. The achieved exact solution is useful for thermal stress analysis of functionally graded cylinders. Regarding the analytical approach, this solution can be used to understand the concepts of heat conduction in functionally graded materials.

Keywords: functionally graded materials, unsteady heat conduction, cylinder, temperature distribution

Procedia PDF Downloads 274

Authors: N. Guruprasad

Abstract:

This paper presents a modification of approximation method for transportation problems. The initial basic feasible solution can be computed using either Russel's or Vogel's approximation methods. Russell’s approximation method provides another excellent criterion that is still quick to implement on a computer (not manually) In most cases Russel's method yields a better initial solution, though it takes longer than Vogel's method (finding the next entering variable in Russel's method is in O(n1*n2), and in O(n1+n2) for Vogel's method). However, Russel's method normally has a lesser total running time because less pivots are required to reach the optimum for all but small problem sizes (n1+n2=~20). With this motivation behind we have incorporated a variation of the same – what we have proposed it has TMC (Total Modified Cost) to obtain fast and efficient solutions.

Keywords: computation, efficiency, modified cost, Russell’s approximation method, transportation, Vogel’s approximation method

Procedia PDF Downloads 500

Authors: Kimia Kiaei, Mohammad Hasan Golpayegani

Abstract:

The extraction of copper from a pregnant leach solution obtained through leaching was investigated in this study. Chemorex CP-150 was utilized as an organic extractant, while kerosene served as a diluent. The study focused on determining the optimal ratios of extractant to diluent, as well as the pH of the aqueous phase. Isotherm curves of extraction were generated, and Mc. Cabe-Thiele diagrams were constructed separately for an optimized experimental pH of 3.17 and a typical industrial pH of 2. Additionally, the sulfuric acid-to-PLS ratio and concentrations of interfering ions comprising Mn²⁺ and Fe³⁺ in the strip solution were evaluated during the stripping stage. The results indicated that the optimized values for the extractant-to-diluent ratio and pH were 5% and 3.17, respectively. The Mc. Cabe-Thiele diagrams revealed that at an aqueous-to-organic ratio of 1, the theoretical stages of solvent extraction at pH levels of 3.17 and 2 were one and two, respectively. Moreover, a sulfuric acid-to-PLS ratio of 20% was employed in the stripping stage, and it was observed that the concentrations of interfering ions fell within the acceptable range.

Keywords: copper, solvent extraction, heap leaching, Chemorex CP-150, pregnant leach solution

Procedia PDF Downloads 34

Authors: K. Sever, Y. Seki, Z. Yenier, İ. Şen, M. Sarikanat

Abstract:

It is known that Chitosan, as a natural polymer, has many excellent properties such as bicompotability, biodegradability and nontoxicity. Besides it has some limitations such as poor solubility in water and low conductivity in electrical devices and sensor applications. In order to improve electrical conductivity properties grapheme loading was conducted into chitosan. For this aim, chitosan solution was prepared in acidic condition and Graphene at different ratios was mixed with chitosan solution by the help of homogenizator. After film formation electrical conductivity values of chitosan and graphene loaded chitosan were determined. After grapheme loading into chitosan,solution significant increases in surface resistivity value of chitosan were observed. Besides variations on viscoeleastic properties with graphene loading was determined by dynamic mechanical analysis. Storage and Loss moduli were obtained for chitosan and grapheme loaded chitosan samples.

Keywords: chitosan, graphene, viscoelastic properties, electrical conductivity

Procedia PDF Downloads 448

Authors: James Adewale, Joshua Sunday

Abstract:

In this paper, we developed a linear multistep method, which is implemented in predictor corrector-method. The corrector is developed by method of collocation and interpretation of power series approximate solutions at some selected grid points, to give a continuous linear multistep method, which is evaluated at some selected grid points to give a discrete linear multistep method. The predictors were also developed by method of collocation and interpolation of power series approximate solution, to give a continuous linear multistep method. The continuous linear multistep method is then solved for the independent solution to give a continuous block formula, which is evaluated at some selected grid point to give discrete block method. Basic properties of the corrector were investigated and found to be zero stable, consistent and convergent. The efficiency of the method was tested on some linear, non-learn, oscillatory and stiff problems of first order, initial value problems of ordinary differential equations. The results were found to be better in terms of computer time and error bound when compared with the existing methods.

Keywords: predictor, corrector, collocation, interpolation, approximate solution, independent solution, zero stable, consistent, convergent

Procedia PDF Downloads 472

Authors: Mohammed A. Al-Ajmi, Reem S. Al-Kandari

Abstract:

This study is concerned with the behavior of engineering students in Kuwait University which became a concern due to the global issues of education in all levels. A survey has been conducted to identify academic and societal issues that affect the engineering student performance through. The study is drawing major conclusions with regard to private tutoring and the online availability of textbooks’ solution manuals.

Keywords: solution manual, engineering, textbook, ethics

Procedia PDF Downloads 465

Authors: S. Aizikovich, L. Krenev, Y. Tokovyy, Y. C. Wang

Abstract:

An approximate analytical-numerical solution to the axisymmetric problem on thermo-mechanical indentation of a flat cylindrical punch into an arbitrarily non-homogeneous elastic half-space is constructed by making use of the bilateral asymptotic method. The key point of this method lies in evaluation of the ker¬nels in the obtained integral equations by making use of a numerical technique. Once the structure of the kernel is defined, it then is approximated by an analytical expression of special kind so that the solution of the integral equation can be achieved analytically. This fact allows for construction of the solution in an analytical form, which is convenient for analysis of the mechanical effects concerned with arbitrarily presumed non-homogeneity of the material.

Keywords: contact problem, circular punch, arbitrarily-nonhomogeneous halfspace

Procedia PDF Downloads 494

Authors: H. Abchiche, M. Mellal

Abstract:

The aim of this work is to study the parameters that influence the rheological behavior of a complex fluid (sodium Carboxyméthylcellulose solution), on a capillary rheometer. An installation has been made to be able to vary the diameter of trial conducts. The obtained results allowed us to deduce that: the diameter of trial conducts have a remarkable effect on the rheological responds.

Keywords: bingham’s fluid, CMC, cylindrical conduit, rheological behavior

Procedia PDF Downloads 302

Authors: Su-Thing Ho, Shiao-Shing Chen, Hung-Te Hsu, Saikat Sinha Ray

Abstract:

Forward osmosis (FO) is an emerging technology for direct and indirect potable water reuse application. However, successful implementation of FO is still hindered by the lack of draw solution recovery with high efficiency. Membrane distillation (MD) is a thermal separation process by using hydrophobic microporous membrane that is kept in sandwich mode between warm feed stream and cold permeate stream. Typically, temperature difference is the driving force of MD which attributed by the partial vapor pressure difference across the membrane. In this study, the direct contact membrane distillation (DCMD) system was used to recover diluted draw solution of FO. Na3PO4 at pH 9 and EDTA-2Na at pH 8 were used as the feed solution for MD since it produces high water flux and minimized salt leakage in FO process. At high pH, trivalent and tetravalent ions are much easier to remain at draw solution side in FO process. The result demonstrated that PTFE with pore size of 1 μm could achieve the highest water flux (12.02 L/m2h), followed by PTFE 0.45 μm (10.05 L/m2h), PTFE 0.1 μm (7.38 L/m2h) and then PP (7.17 L/m2h) while using 0.1 M Na3PO4 draw solute. The concentration of phosphate and conductivity in the PTFE (0.45 μm) permeate were low as 1.05 mg/L and 2.89 μm/cm respectively. Although PTFE with the pore size of 1 μm could obtain the highest water flux, but the concentration of phosphate in permeate was higher than other kinds of MD membranes. This study indicated that four kinds of MD membranes performed well and PTFE with the pore size of 0.45 μm was the best among tested membranes to achieve high water flux and high rejection of phosphate (99.99%) in recovery of diluted draw solution. Besides that, the results demonstrate that it can obtain high water flux and high rejection of phosphate when operated with cross flow velocity of 0.103 m/s with Tfeed of 60 ℃ and Tdistillate of 20 ℃. In addition to that, the result shows that Na3PO4 is more suitable for recovery than EDTA-2Na. Besides that, while recovering the diluted Na3PO4, it can obtain the high purity of permeate water. The overall performance indicates that, the utilization of DCMD is a promising technology to recover the diluted draw solution for FO process.

Keywords: membrane distillation, forward osmosis, draw solution, recovery

Procedia PDF Downloads 162

Authors: Manojkumar Sabanayagam

Abstract:

The Riemann hypothesis is an unsolved millennium problem and the search for a solution to the Riemann hypothesis is to study the pattern of prime number distribution. The scope of this paper is to identify the solution for the critical strip and the critical line axis, which has the non-trivial zero solutions using complex plane functions. The Riemann graphical plot is constructed using a linear complex variable function (X+iY) and is applicable only when X>1. But the investigation shows that complex variable behavior has two zones. The first zone is the transformation zone, where the definition of the complex plane should be a non-linear variable which is the critical strip zone in the graph (X=0 to 1). The second zone is the transformed zone (X>1) defined using linear variables conventionally. This paper deals with the Non-linear function in the transformation zone derived using cosine and sinusoidal time lag w.r.t imaginary number ‘i’. The alternate complex variable (Cosθ+i Sinθ) is used to understand the variables in the critical strip zone. It is concluded that the non-trivial zeros present in the Real part 0.5 are because the linear function is not the correct approach in the critical strip. This paper provides the solution to Reimann's hypothesis.

Keywords: Reimann hypothesis, critical strip, complex plane, transformation zone

Procedia PDF Downloads 179

Authors: M. Chavez, H. Juarez, M. Pacio, O. Portillo

Abstract:

PbS chemical bath heterojunction sollar cells have shown significant improvements in performance. Here we demonstrate a solar cell based on the heterojunction formed between PbS layer and PbS:Bi3+ thin films that are deposited via solution process at 40°C. The device achieve an current density of 4 mA/cm2. The simple and low-cost deposition method of PbS:Bi3+ films is promising for the fabrication.

Keywords: PbS doped, Bismuth, solar cell, thin films

Procedia PDF Downloads 520

Authors: Ehsan Yadegari

Abstract:

While there are several metaheuristics and exact approaches to solving the Supply Chain Network Design (SCND) problem, there still remains an unfilled gap in using the Teaching-Learning-Based Optimization (TLBO) algorithm. The algorithm has demonstrated desirable results with problems with complicated combinational optimization. The present study introduces a Discrete Self-Study TLBO (DSS-TLBO) with priority-based solution representation that can solve a supply chain network configuration model to lower the total expenses of establishing facilities and the flow of materials. The network features four layers, namely suppliers, plants, distribution centers (DCs), and customer zones. It is designed to meet the customer’s demand through transporting the material between layers of network and providing facilities in the best economic Potential locations. To have a higher quality of the solution and increase the speed of TLBO, a distinct operator was introduced that ensures self-adaptation (self-study) in the algorithm based on the four types of local search. In addition, while TLBO is used in continuous solution representation and priority-based solution representation is discrete, a few modifications were added to the algorithm to remove the solutions that are infeasible. As shown by the results of experiments, the superiority of DSS-TLBO compared to pure TLBO, genetic algorithm (GA) and firefly Algorithm (FA) was established.

Keywords: supply chain network design, teaching–learning-based optimization, improved metaheuristics, discrete solution representation

Procedia PDF Downloads 15

Authors: Tomer Gans-Or, Shmulik Pinkert

Abstract:

The determination of lateral pile capacity per unit length is a key aspect in geotechnical engineering. Traditional approaches for assessing piles lateral capacity in cohesive soils involve the application of upper-bound and lower-bound plasticity theorems. However, a comprehensive solution encompassing the entire spectrum of soil strength parameters, particularly in frictional soils with or without cohesion, is still lacking. This research introduces an innovative implementation of the slice method limit equilibrium solution for lateral capacity assessment. For any given numerical discretization of the soil's domain around the pile, the lateral capacity evaluation is based on mobilized strength concept. The critical failure geometry is then found by a unique optimization procedure which includes both factor of safety minimization and geometrical optimization. The robustness of this suggested methodology is that the solution is independent of any predefined assumptions. Validation of the solution is accomplished through a comparison with established plasticity solutions for cohesive soils. Furthermore, the study demonstrates the applicability of the limit equilibrium method to address unresolved cases related to frictional and cohesive-frictional soils. Beyond providing capacity values, the method enables the utilization of the mobilized strength concept to generate safety-factor distributions for scenarios representing pre-failure states.

Keywords: lateral pile capacity, slice method, limit equilibrium, mobilized strength

Procedia PDF Downloads 24

Authors: Fuziyah Ishak, Siti Norazura Ahmad

Abstract:

Volterra integro-differential equations appear in many models for real life phenomena. Since analytical solutions for this type of differential equations are hard and at times impossible to attain, engineers and scientists resort to numerical solutions that can be made as accurately as possible. Conventionally, numerical methods for ordinary differential equations are adapted to solve Volterra integro-differential equations. In this paper, numerical solution for solving Volterra integro-differential equation using extended trapezoidal method is described. Formulae for the integral and differential parts of the equation are presented. Numerical results show that the extended method is suitable for solving first order Volterra integro-differential equations.

Keywords: accuracy, extended trapezoidal method, numerical solution, Volterra integro-differential equations

Procedia PDF Downloads 393

Authors: Vahid Zeighami, Mohsen Ghsemi, Reza Akbari

Abstract:

In this work, a Multi-Level Artificial Bee Colony (called MLABC) is presented. In MLABC two species are used. The first species employs n colonies in which each of the them optimizes the complete solution vector. The cooperation between these colonies is carried out by exchanging information through a leader colony, which contains a set of elite bees. The second species uses a cooperative approach in which the complete solution vector is divided to k sub-vectors, and each of these sub-vectors is optimized by a a colony. The cooperation between these colonies is carried out by compiling sub-vectors into the complete solution vector. Finally, the cooperation between two species is obtained by exchanging information between them. The proposed algorithm is tested on a set of well known test functions. The results show that MLABC algorithms provide efficiency and robustness to solve numerical functions.

Keywords: artificial bee colony, cooperative, multilevel cooperation, vector

Procedia PDF Downloads 415

Authors: Abduraheem K., Suboohi Nasrin

Abstract:

Herbaria are specimens of preserved plants, which are very delicate and cellulosic in nature. While these collections are very useful for the enrichment of knowledge and are considered as natural heritage of our entire world, it is very important to preserve and conserve them. The significance is not only to prevent the herbaria from the deterioration of biological agencies but also to preserve its colours and retain natural colour. Colour is not only characteristic of a plant, but it can also help to identify closely related species or to distinguish a plant from a collection of herbaria. Keeping this in mind, a selective solution has been prepared for the conservation and preservation of herbarium in the present study. In this, the quantity of all the selected chemicals, i.e., formaldehyde and copper sulphate was kept constant, and the solution was prepared by dissolving it in distilled water by increasing the amount of picric acid (1, 2, 3, 4, and 5 ml). Fresh specimens of roses and bougainvillea were washed with distilled water and kept in the above solution for 10 to 15 minutes at room temperature. After 10 minutes, the specimen was removed from the solution, dried with the help of paper, and then pressed under the plant press. Blotting sheets were used to absorb the moisture content and were changed every 2 to 3 days to protect against fungal growth. The results revealed that all solutions had insecticidal properties and protected the herbarium specimen against pests. While in the case of colour retention, solution-1 and 2 were not satisfactory colour preservation, and solutions-3 and 5 maintained the colour of rose and bougainvillea leaves for 15 to 20 days and for a month, respectively. After that, the colour begins to fade, and the process is faster in rose leaves than in bougainvillea. And it was also observed that the colour of young leaves started to fade before that of older leaves. When the leaves of rose and bougainvillea are treated with Solution-4, then the colour of rose leaves is maintained for six months.

Keywords: solutions, colour retention, preservation and conservation, leaves of roses and bougainvillea

Procedia PDF Downloads 65

Authors: E. Chávez-Vargas, M. de la L. Olvera-Amador, A. Jimenez-Gonzalez, A. Maldonado

Abstract:

Undoped and fluorine doped zinc oxide (ZnO) thin films were deposited on sodocalcic glass substrates by the ultrasonic chemical spray technique. As the main goal is the manufacturing of transparent electrodes, the effects of both the solution composition and the substrate temperature on both the electrical and optical properties of ZnO thin films were studied. As a matter of fact, the effect of fluorine concentration ([F]/[F+Zn] at. %), solvent composition (acetic acid, water, methanol ratios) and ageing time, regarding solution composition, were varied. In addition, the substrate temperature and the deposition time, regarding the chemical spray technique, were also varied. Structural studies confirm the deposition of polycrystalline, hexagonal, wurtzite type, ZnO. The results show that the increase of ([F]/[F+Zn] at. %) ratio in the solution, decreases the sheet resistance, RS, of the ZnO:F films, reaching a minimum, in the order of 1.6 Ωcm, at 60 at. %; further increase in the ([F]/[F+Zn]) ratio increases the RS of the films. The same trend occurs with the variation in substrate temperature, as a minimum RS of ZnO:F thin films was encountered when deposited at TS= 450 °C. ZnO:F thin films deposited with aged solution show a significant decrease in the RS in the order of 100 ΩS. The transmittance of the films was also favorable affected by the solvent ratio and, more significantly, by the ageing of the solution. The whole evaluation of optical and electrical characteristics of the ZnO:F thin films deposited under different conditions, was done under Haacke’s figure of Merit in order to have a clear and quantitative trend as transparent conductors application.

Keywords: zinc oxide, ZnO:F, TCO, Haacke’s figure of Merit

Procedia PDF Downloads 284

Authors: M. Mosaad, J. H. Almutairi, A. S. Almutairi

Abstract:

In this paper, saturated-vapour film condensation on a vertical wall with the backside cooled by forced convection is analyzed as a conjugate problem. In the analysis, the temperature and heat flux at the wall sides are assumed unknown and determined from the solution. The model is presented in a dimensionless form to take a broad view of the solution. The dimensionless variables controlling this coupled heat transfer process are discovered from the analysis. These variables explain the relative impact of the interactive heat transfer mechanisms of forced convection and film condensation. The study shows that the conjugate treatment of film condensation process yields results different from that predicted by a non-conjugate Nusselt-type solution, wherein the effect of the cooling fluid is neglected.

Keywords: film condensation, forced convection, coupled heat transfer, analytical modelling

Procedia PDF Downloads 285

Authors: A. M. Sagir

Abstract:

The aim of this paper is to investigate the performance of the developed linear multistep block method for solving first order initial value problem of Ordinary Differential Equations (ODEs). The method calculates the numerical solution at three points simultaneously and produces three new equally spaced solution values within a block. The continuous formulations enable us to differentiate and evaluate at some selected points to obtain three discrete schemes, which were used in block form for parallel or sequential solutions of the problems. A stability analysis and efficiency of the block method are tested on ordinary differential equations involving practical applications, and the results obtained compared favorably with the exact solution. Furthermore, comparison of error analysis has been developed with the help of computer software.

Keywords: block method, first order ordinary differential equations, linear multistep, self-starting

Procedia PDF Downloads 277

Authors: P. Hari Prasad Reddy, Shimna Paulose, V. Sai Kumar, C. H. Rama Vara Prasad

Abstract:

Soil environment gets contaminated due to rapid industrialisation, agricultural-chemical application and improper disposal of waste generated by the society. Unexpected volume changes can occur in soil in the presence of certain contaminants usually after the long duration of interaction. Alkali is one of the major soil contaminant that has a considerable effect on behaviour of soils and capable of inducing swelling potential in soil. Chemical heaving of clayey soils occurs when they are wetted by aqueous solutions of alkalis. Mineralogical composition of the soil is one of the main factors influencing soil- alkali interaction. In the present work, studies are carried out to understand the swell potential of soils due to soil-alkali interaction with different concentrations of NaOH solution. Locally available soil, namely, red earth containing kaolinite which is of non-swelling nature is selected for the study. In addition to this, two commercially available clayey soils, namely ball clay and china clay containing mainly of kaolinite are selected to understand the effect of alkali interaction in various kaolinitic soils. Non-swelling red earth shows maximum swell at lower concentrations of alkali solution (0.1N) and a slightly decreasing trend of swelling with further increase in concentration (1N, 4N, and 8N). Marginal decrease in swell potential with increase in concentration indicates that the increased concentration of alkali solution exists as free solution in case of red earth. China clay and ball clay both falling under kaolinite group of clay minerals, show swelling with alkaline solution. At lower concentrations of alkali solution both the soils shows similar swell behaviour, but at higher concentration of alkali solution ball clay shows high swell potential compared to china clay which may be due to lack of well ordered crystallinity in ball clay compared to china clay. The variations in the results obtained were corroborated by carrying XRD and SEM studies.

Keywords: alkali, kaolinite, swell potential, XRD, SEM

Procedia PDF Downloads 462

Authors: Miguel Mariano Rivera Galvan

Abstract:

The purpose of this research was to create a digital tool by which users can obtain an immediate and accurate solution of the angular characteristics of an irregular quadrilateral. The development of this project arose because of the frequent absence of a polygon’s geometric information in land ownership accreditation documents. The researcher created a mathematical model using a linear approximation iterative method, employing various disciplines and techniques including trigonometry, geometry, algebra, and topography. This mathematical model uses as input data the surface of the quadrilateral, as well as the length of its sides, to obtain its interior angles and make possible its representation in a coordinate system. The results are as accurate and reliable as the user requires, offering the possibility of using this tool as a support to develop future engineering and architecture projects quickly and reliably.

Keywords: digital tool, geometry, mathematical model, quadrilateral, solution

Procedia PDF Downloads 117

Authors: Ji Chan Kim, Seok Hong Min, Tae Kwon Ha

Abstract:

Effect of boron addition on the microstructure and mechanical properties of AZ91D Mg alloy was investigated in this study. Through calculation of phase equilibria, carried out by using FactSage® and FTLite database, solution treatment temperature was decided as 420 °C where supersaturated solid solution can be obtained. Solid solution treatment was conducted at 420 °C for 24 hrs followed by hot rolling at 420 °C and the total reduction was about 60%. Recrystallization heat treatment was followed at 420 °C for 6 hrs to obtain equiaxed microstructure. After recrystallization treatment, aging heat treatment was conducted at temperature of 200 °C for time intervals from 1 min to 200 hrs and hardness of each condition was measured by micro-Vickers method. Peak hardness was observed after 20 hrs. Tensile tests were also conducted on the specimens aged for various time intervals and the results were compared with hardness.

Keywords: AZ91D Mg alloy, boron, heat treatment, microstructure, mechanical properties, hardness

Procedia PDF Downloads 283

Authors: Mahmoud A. Rabah, Said El Sheikh

Abstract:

This work shows the preparation of chromium nanoparticles from tannery waste solution on glassy carbon by chemical method compared to electrokinetic process. The waste solution contains free and soluble fats, calcium, iron, magnesium and high sodium in addition to the chromium ions. Filtration helps removal of insoluble matters. Diethyl ether successfully extracted soluble fats. The method started by removing calcium as insoluble oxalate salts at hot conditions in a faint acidic medium. The filtrate contains iron, magnesium, chromium ions and sodium chloride in excess. Chromium was separated selectively as insoluble hydroxide sol-gel at pH 6.5, filtered and washed with distilled water. Part of the gel reacted with sulfuric acid to produce chromium sulfate solution having 15-25 g/L concentration. Electrokinetic deposition of chromium nanoparticles on a carbon cathode was carried out using platinum anode under different galvanostatic conditions. The chemical method involved impregnating the carbon specimens with chromium hydroxide gel followed by reduction using hydrazine hydrate or by thermal reduction using hydrogen gas at 1250°C. Chromium grain size was characterized by TEM, FT-IR and SEM. Properties of the Cr grains were correlated to the conditions of the preparation process. Electrodeposition was found to control chromium particles to be more identical in size and shape as compared to the chemical method.

Keywords: chromium, electrodeposition, nanoparticles, tannery waste solution

Procedia PDF Downloads 375

Authors: Nosakhare Enoma, Alphose Zingoni

Abstract:

The requirements for various toroidal shell forms are increasing due to new applications, available storage space and the consideration of appearance. Because of the complexity of some of these structural forms, the finite element method is nowadays mainly used for their analysis, even for simple static studies. This paper presents an easy-to-use analytical algorithm for pressurized multi-segmented toroidal shells of revolution. The membrane solution, which acts as a particular solution of the bending-theory equations, is developed based on membrane theory of shells, and a general approach is formulated for quantifying discontinuity effects at the shell junctions using the well-known Geckeler’s approximation. On superimposing these effects, and applying the ensuing solution to the problem of the pressurized toroid with four segments, closed-form stress results are obtained for the entire toroid. A numerical example is carried out using the developed method. The analytical results obtained show excellent agreement with those from the finite element method, indicating that the proposed method can be also used for complementing and verifying FEM results, and providing insights on other related problems.

Keywords: bending theory of shells, membrane hypothesis, pressurized toroid, segmented toroidal vessel, shell analysis

Procedia PDF Downloads 288