Papers by Keyword: Model

Abstract: Environmental contamination might result from sawdust waste that has not been adequately managed. However, waste has a high economic value. This study aimed to analyze the characteristic model of sawdust after the carbonization process. The research method used the L9(3)4 Orthogonal Array experiment. The research variables included: drying temperature (X₁), drying time (X₂), carbonization temperature (X₃), and carbonization time (X₄), each with three levels of factors. The research response variables were moisture content (Y₁), volatile matter (Y₂), ash (Y₃), and fixed carbon (Y₄) of sawdust charcoal. The results showed that the average moisture content was 0.9%, volatile matter 8.3%, ash content 8.29%, and fixed carbon content 82.51%. According to the outcomes of multiple linear regression analysis, the correlation coefficients (R) of the four were very significant for moisture content, volatile matter, ash, and fixed carbon of 0.865, 0.929, 0.987, and 0.935, respectively. The optimum conditions obtained were water content X_1-2X_2-3X_3-3X_4-3, volatile material X_1-1X_2-1X_3-1X_4-1, ash content X_1-1X_2-1X_3-1X_4-1, and carbon content X_1-2X_2-1X_3-1X_4-1. The outcomes of the sawdust charcoal proximate analysis model validation test were normally distributed, and there was no homoscedasticity, multicollinearity, or negative autocorrelation. Thus, the four models produced in this study were feasible and valid so that they could use them to predict the physical material characteristics of teak sawdust.

Abstract: Warp knitting is appointed as a manufacturing method for high-performance and high-quality textiles due to its versatility and production speed. To ensure a continuous and error-free manufacturing process under highly dynamic production conditions, a high level of knowledge of the yarn and machine interaction is required. Mechanical stresses from the machine are transferred to the yarn via friction points, as well as during the stitching process from one yarn to another, where the yarn is subjected to high stresses.Therefore, the focus of this research is the investigation of the friction between the yarn and yarn guiding elements and the friction between the yarns themselves during the stitch formation. For this reason, all contact points between yarn and yarn guiding elements as well as between the yarns themselves are examined and classified. A test rig is set up to determine all occurring frictions as a function of various machine parameters.The knowledge gained and the derived analytical expressions between machine settings and occurring friction can thus become the basis for modeling the friction points of the warp knitting machine, which is also presented. Furthermore, based on the findings a design improvement of the machine can be achieved and the friction model can serve as part of a simulation model of the entire warp knitting machine, which will be the focus of further publications.

Abstract: Wafer scratching from handling and processing can impact the performance of devices grown on a substrate. Knowledge of process conditions and modeling of scratches on wafers can be used to elucidate the root cause of scratches so that they can be eliminated.

Abstract: This study was carried out to ascertain the optimum parameters for maximum total acid number (TAN) reduction via catalytic esterification using chicken eggshell ash as catalyst. A central composite design (CCD) was created to optimize TAN reduction by varying temperature and catalyst weight %. The chicken eggshell ash was calcined and reactivated in a furnace at 900 °C for an hour. An oil solution (referred to as synthetic solution) of diesel was adulterated with the organic acid m-toluic which served as a representation for highly acidic oil. Titration using alcoholic potassium hydroxide (KOH) and an indicator (phenolphthalein) was used to deduce the total acid number of the synthetic solution before and after esterification. The optimum parameters for maximum TAN reduction obtained from the model were a temperature of 56.90 °C, a catalyst weight % of 11.45%, and a maximum TAN reduction of approximately 94%. Fourier Transform Infrared (FTIR) Spectroscopy also confirmed that TAN reduction had taken place as the peaks that represent the carbonyl group (C=O stretch at ~1605 cm-1) was reduced significantly.

Abstract: Gear hones are used as tools for gear honing. The efficiency of using gear hones mainly depends on the parameters of their compound material, first of all on the wear resistance and elasticity modulus. In terms of the elasticity modulus, gear hones can be hard and elastic, depending on the bonding agent type. Experience shows that gear-hone teeth distort during gear honing; they feature contact and flexural deformation and wear during metal removal, including along the tooth space. For this reason, it is necessary to consider the deformation and wear values for designing of gear hone geometry. An approach for calculation of variable engagement parameters, using a geometrical model in the form of sliding trapezoids to consider the dimensional wear of gear-hone teeth based on the positive correlation factor of the original profile. Such designing of gear-hone teeth provides sufficient thickness in the original section, which ensures high performance capacity of gear-honing tools and required workability.

Abstract: Within the framework of the Economic Community of West African States (ECOWAS) countries power networks interconnection project carried by the West African Power Pool (WAPP), operating guidelines have been defined by WAPP and ECOWAS Regional Electricity Regulatory Authority (ERERA) to ensure efficient operation of the interconnected network. Each operator is obliged to comply with these directives to guarantee the stability and reliability of energy supply to ECOWAS countries. The purpose of this paper is to carry out the study of the power flow on the existing Togo and Benin power transmission network and to propose solutions for compliance with the requirements relating to the voltage level required on the interconnection lines or at connection points with neighboring power network operators. The dynamic stability of generators will also be studied to assess the behavior of the network during major disturbances. CEB (Communauté Electrique du Bénin in french) is the power transmission network operator of the Republic of Togo and the Republic of Benin. After the inventory of CEB transmission and production infrastructure and the consumption report, the model of CEB power network is produced as well as the single-line diagram. The power flow calculation is performed with the Newton-Raphson algorithm and the node voltages were calculated using the Cyme software. From the voltage values obtained at the various nodes and depending on the behavior of each generator, solutions are proposed to improve the voltage plan of the power network in accordance with the recommendations of the Regulatory Authority.

Abstract: Over a long period of operation, under the influence of corrosion and stresses from the acting forces, metal structures lose their strength. There is a need for their periodic non-destructive testing. The development of new methods is relevant in the field of control of building metal structures, such as bridge structures, structures of building cranes and other mechanical engineering products. The applied methods should be reliable and should not require huge material and labor costs. In this work, informational relationships between acoustic characteristics and parameters of metal microstructure are established. The proposed method can be useful for specialists and experts in the field of monitoring the technical condition of metal products requiring non-destructive testing. The safety of the operated objects depends on the accuracy of the applied criteria, as well as the degree of resource saving due to the full use of the product resource.

Abstract: Due to its ecological interest and large availability, a renewed attention is paid to earth as building material. Indeed, raw earth consumes CO₂ only during its processing and transportation, and it provides a natural hygrothermal comfort. However, its mechanical properties are highly linked to its composition, which causes an important variability of performances. That is why any soil has to be characterized before being used as a building material. The aim of this study is to propose a model able to predict the hydromechanical behavior of a reconstituted soil according to its composition. As earth is a heterogeneous material, the model is based on homogenization procedures. The sand is considered as spherical inclusions inside a clay matrix. The particularity of the model stands to consider both positive and negative effects of volume variation and mechanical properties of clay under hydric variations. The model parameters are determined according to an original experimental campaign, which is conducted on various mixes of a single type of clay (kaolinite) and of sand, and water. The experimental study provides some mechanical properties of the mixes versus water content and sand content to test the ability of the homogenization model to assess the main properties of this material.

Abstract: The output power of Direct Methanol Fuel Cells (DMFC) is one of the most important elements which limit the performance of DMFC. In order to enhance performance of DMFC, it is necessary to have model to modeling the output power of DMFC. In this paper, a novel model base on Support Vector Regression (SVR) to modeling the output power of DMFC base on output current (I) and operating temperature (T). The test result is shown that the generalization ability of SVR model is high accuracy. This investigation suggests that SVR is quite satisfied used to developing a DMFC model and can be used for controlling, optimal designing and feasibility study of the DMFC system.

Abstract: Ultrasound-Assisted Extraction (UAE) was applied to enhance the bioactive compound extraction from the intact red sorghum grains using water as a green solvent that is relatively more available, safe, and less contaminant to the product application. The UAE performance of the ultrasonic probe with 60, 70, and 80% amplitude were compared to evaluate the effect of ultrasound amplitude. A mechanistic model was applied for quantitative evaluation of the UAE performance and prediction of the concentration of total phenolic (TP) and proanthocyanidin (PC) in the extract during the extraction. This research evaluated the effect of amplitude on the extraction rate, the parameters in the model, and the predicted TP and PC concentration from the mechanistic model approach. The wave enhanced the extraction by its propagation, cavitation bubble, and pericarp destruction. The mass transfer coefficient was stretched between 1.271×10^–2 - 1.345×10^–2 cm^–1/minutes for TP and 5.979×10^–3 - 8.262×10^–3 cm^–1/minutes for PC, while the distribution coefficient was 2.222×10^–2 -2.248×10^–2 grain/cm^–3 solvent for TP and 6.739×10^–2 - 7.946×10^–2 grain/cm^–3 solvent for PC. The highest performance resulted from 80% amplitude. The model worked precisely to predict the concentration of TP and PC of UAE, illustrating the amplitude’s effect in enhancing the UAE from its parameter values.