Browsing by Publisher "University of Kuwait"
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Item An infinite dimensional fixed point theorem on function spaces of ordered metric spaces(University of Kuwait, 2015) Mutlu A.; Gürdal U.In this study, we extend the notion of multidimensional fixed point and coincidence point theorem to infinite dimensional product spaces. We also prove some theorems, which generalizes some results that are known in this field.Item Relations between a dual unit vector and Frenet vectors of a dual curve(University of Kuwait, 2016) Şahiner B.; Önder M.In this paper, we generalize the notions of helix and slant helix in dual space in a more general case such as the dual angle between a fixed dual unit vector and Frenet vectors of a dual curve is not constant. We study the motions of the lines corresponding to dual Frenet vectors and dual Frenet instantaneous rotation vector with respect to a fixed line. We obtain some characterizations for such dual curves and show that these characterizations include the definitions and characterizations of dual helix and dual slant helix in some special cases. © 2016, University of Kuwait. All rights reserved.Item Slant null scrolls in Minkowski 3-space E13(University of Kuwait, 2016) Önder M.; Kaya O.In this study, we introduce a new type of null scrolls called slant null scrolls in Minkowski 3-space E13. We define three types of slant null scrolls called α-slant, β-slant and γ-slant null scrolls and give characterizations for a null scroll to be a slant null scroll. Moreover, for β-slant null scrolls, we obtain some nonlinear differential equations and we give some results by using their analytical solutions. Finally, we give some examples for the obtained results.Item The performance prediction of roadheaders with response surface analysis for underground metal mine(University of Kuwait, 2017) Özfirat K.M.; Malli T.; Özfirat P.M.; Kahraman B.Roadheaders are being used in development roads in underground mines. Especially, as total reserve is enough for large investments and mine roads, roadheaders are important to increase production rate. Roadheaders are classified according to the weight head drive or total power. In this study, the effects of several factors on roadheader performance is examined. The factors examined are power of the machine, weight of the machine, ratio of power to weight, drilling rate index, uniaxial compressive strength and rock mass rating. Instantaneous cutting ratio is used to define the performance of the machine. Response surface methodology and linear regression are used to investigate the relations between these variables. In the results of the study, machine performance is found to be highly correlated with machine power (P), weight (W) and the P/W ratio of the machine.Item On rectifying ruled surfaces(University of Kuwait, 2020) Önder M.; Kahraman T.In this study, we define general rectifying ruled surfaces in the Euclidean 3-space E3 . We give some characterizations of rectifying ruled surfaces by considering the curvatures of base curve. We obtain the Gaussian curvature and the mean curvature and we investigate the condition for the surface to be minimal. Moreover, we give characterizations for some special curves lying on this surface. Finally, we obtain the relationships between rectifying ruled surfaces and slant ruled surfaces. © 2020 University of Kuwait. All rights reserved.Item Dynamical analysis of the general beam model with singularity function(University of Kuwait, 2021) Dönmez Demir D.; Sinir B.G.; Kahraman E.The aim of this study is to present a general model with variable coefficients corresponding to some structural elements such as beam, string, bar, and rod. To solve general model with variable coefficients, a different solution procedure combining a method of multiple scales (MMS) and a finite difference method (FDM) is presented in this study. This technique provides an advantage in the numerical solution of the structural element model containing any discontinuity and in its dynamical analysis by perturbation method. Furthermore, two problems including discontinuity are considered to show the accuracy of the method presented. The comparisons of the numerical results obtained from the proposed method and classical method are introduced. © 2021 University of Kuwait. All rights reserved.Item Investigation of tool wear, surface roughness, sound intensity, and power consumption during hard turning of AISI 4140 steel using multilayer-coated carbide inserts(University of Kuwait, 2021) Şahinoǧlu A.; Rafighi M.The present study investigated the machinability aspects, namely, surface roughness, sound intensity, power consumption, and crater wear, during dry turning of hardened AISI 4140 steel (63 HRC) employing (TiCN/Al2O3/TiN) multilayer-coated carbide inserts under dry cutting condition. The relationship between machining parameters and output parameters was determined using the Taguchi design. The analysis of variance was employed to evaluate the contributions of input parameters on output parameters. The main effect plots illustrated the impacts of cutting speed, feed, and depth of cut on response variables. Results show that the feed was the most dominant factor that affects surface roughness. Increasing the feed value increases the surface roughness, power consumption, and sound intensity. In the other part of this study, the constant values for feed (0.3 mm/rev), depth of cut (0.7 mm), and cutting speed (150 m/min) have been selected to evaluate a tool life that has 0.3 mm crater wear criteria. The results indicated that multilayer-coated carbide inserts presented very good tool life and reached 0.3 mm in 90 min. The experimental study results showed that chipping and abrasion were found to be the significant wear mechanism during hard turning of AISI 4140 steel. The cutting speed was the most significant parameter on the tool wear, although high cutting speed results the good surface finish but adversely increases the tool crater wear. © 2021 University of Kuwait. All rights reserved.Item A linear physical programming model for assembly line balancing problem(University of Kuwait, 2022) Akpınar M.E.This paper deals with the mixed-model assembly line balancing problem. This type of line is applied to more than one similar model of a product in an intermixed order. Despite their widespread use, these lines have received little attention in the literature. Metaheuristics, heuristics, and mathematical programming techniques are developed to solve these types of assembly line balancing problems. However, linear physical programming method has never been used. In this paper, a linear physical programming model is proposed for balancing a mixed-model assembly line. The performance of the proposed model is applied to a numerical example to analyze the usage of the methodology. Five objectives are considered in the model, and the outperformance of the methodology is demonstrated by comparing it to a different approach. According to the results, it has been seen that the proposed linear physical programming model is practical and useful approach for mixed-model assembly line balancing problems. © 2022 University of Kuwait. All rights reserved.