Recreational tourism as a niche market has prompted researchers to take a variety of approaches to investigate the elements that influence travelers’ decisions to engage in leisure activities. The reasons why Muslim visitors select leisure-based travel are commonly discussed in the tourism literature, although little research has been done in this area. By analyzing the significance of travel motivation, emotional response, and satisfaction in determining attitudinal loyalty for Muslim leisure travelers, this study aims to bridge this knowledge gap. This study employed Confirmatory Factor Analysis (CFA) and Structural Equation Modeling (SEM) using AMOS version 23 to answer the research questions. According to the findings, emotional experiences and extrinsic motives have a good direct impact on satisfaction and an indirect impact on the inclination to return. Having a deeper understanding of leisure-based travel from the perspective of Muslim tourists will benefit recreation managers.

In this study, several series of experiments on turning process of AISI 12L14 free cutting steel characterized by its self-lubrication and the high percentage of lead in its composition were performed to rate the influence of cutting conditions (Vc, f and ap) on the machining performance such as surface roughness, cutting force, cutting power and material removal rate. A computer generated optimal design of experiment based on the I-optimality criteria along with analysis of variance was created to study the characterizations in turning of this steel, and desirability function was utilized for the optimization. The global optimization, combined high surface quality and productivity with low cutting power consumption, gave 12 optimal setting points provided high desirability values. The obtained correlation for surface roughness, cutting force, material removal rate and cutting power were 99.4%, 95.5%, 99.7% and 94.3%, respectively.

The wear of cutting tools remains a major obstacle. The effects of wear are not only antagonistic at the lifespan and productivity, but also harmful with the surface quality. The present work deals with some machinability studies on flank wear, surface roughness, and lifespan in finish turning of AISI 304 stainless steel using multilayer Ti(C,N)/Al2O3/TiN coated carbide inserts. The machining experiments are conducted based on the response surface methodology (RSM). Combined effects of three cutting parameters, namely cutting speed, feed rate and cutting time on the two performance outputs (i.e. VB and Ra), and combined effects of two cutting parameters, namely cutting speed and feed rate on lifespan (T), are explored employing the analysis of variance (ANOVA). The relationship between the variables and the technological parameters is determined using a quadratic regression model and optimal cutting conditions for each performance level are established through desirability function approach (DFA) optimization. The results show that the flank wear is influenced principally by the cutting time and in the second level by the cutting speed. In addition, it is indicated that the cutting time is the dominant factor affecting workpiece surface roughness followed by feed rate, while lifespan is influenced by cutting speed. The optimum level of input parameters for composite desirability was found Vc1-f1-t1 for VB, Ra and Vc1-f1 for T, with a maximum percentage of error 6.38%.

To better meet the qualitative and quantitative requirements of customers or relevant sector managers, workshop environments are implementing increasingly complex task management systems. The job shop scheduling problem (JSSP) involves assigning each task to a single machine while scheduling many tasks on different machines. Finding the best scheduling for machines is one of the challenging optimizations of difficult non-deterministic polynomial (NP) time problems. The fundamental goal of optimization is to shorten the makespan (total execution time of all tasks). This paper is interested in the joint resolution of scheduling and transport problems and more particularly the Job-shop problem with Routing (JSSPR) as opposed to the Job-shop problem with Transport (JSSPT). These two problems are modeled in the form of a disjunctive graph. For the JSSPT, the solution to the transport problem is not linked to any quality of service (QoS) criterion and the solution is therefore often semi-active. The Job-shop with Routing explicitly considers transport operations and uses algorithms from the transport community to solve the transport problem. It is shown that the routing part of the JSSPR is a problem of the vehicle routing family and of the Pickup and Delivery Problem family. QoS in the JSSPR is defined by the duration of tours, the duration of transport of parts and the waiting time for them. A new evaluation function – named Time-Lag Insertion Heuristic (TLH) – is proposed to evaluate a disjunctive graph by simultaneously minimizing the makespan and maximizing the quality of service. Thus, the solution obtained is not semi-active, but a compromise between the different criteria. This evaluation function is included in a metaheuristic. Our numerical evaluations demonstrate that, on the one hand, the TLH evaluation can find almost optimal solutions regarding the QoS criterion; and on the other hand, the TLH evaluation is not very sensitive to the order of insertion of the maximum time-lags during the different minimization steps.

Recently, Lean Six Sigma (LSS) has attracted much attention from both researchers and practitioners. In fact, many published papers used a quantitative research methodology to build and test theory in the field of LSS implementation in manufacturing area. Very few studies have been reported about the critical success factors influencing of six sigma implementations. The aim of this study is to present the results, from an empirical evidence, of Six Sigma implementation in Tunisian manufacturing. Therefore, fourteen main factors have been identified through literature review and questionnaire survey. Interpretive structural modeling (ISM) has been used to develop a hierarchical structure for analyzing the interactions among the key factors. By using the MICMAC technique, the barriers were classified into four groups according to their driving power and dependence power. Our finding provides important insight to managers and practitioners about factors in the LSS implementation process.

This paper presents a mathematical model of nonlinear supersonic flutter of viscoelastic shells. To describe the strain processes in shallow shells, the Boltzmann-Volterra integral model is used. Based on linear integral models in geometrically nonlinear formulations, equations of nonlinear oscillations of shallow shells are derived. The Koltunov-Rzhanitsyn kernel is used as a relaxation kernel. The equations of motion of shallow shells after applying the Bubnov-Galerkin method in axial coordinates are reduced to solve a system of nonlinear integro-differential equations (IDE) with variable coefficients relative to the time function. The IDE solution is found numerically using quadrature formulas.

The study of structures in engineering solid mechanics is very often requires the modeling of complexes structures composed of two parts of thin and thick structure elements. As examples is associated with the case of stiffener under a dome and the cooling tower of the nuclear power which is supported on massive supports. In the numerical analysis, this imposes the connection between two different types of finite elements, two dimensional element for thin structures and three-dimensional elements for solid structures. Knowing that solid finite elements contain only translational degrees of freedom, whereas the finite elements of thin shells includes nodal variables of rotations, and then the number of degrees of freedom are not compatible in the junction zone between these two types of structures. This obviously causes great difficulty in solving the problem numerically. The objective of this work is to present the development of a shell finite element with no degree of freedom of rotation that can be used for the modeling of these two different types of structures and can then easily solve the shell-solid junction problem. Validation tests of the developed element are presented and the results obtained are very encouraging.

The present work concerns an experimental study of turning with coated cermet tools with TiCN-TiN coating layer of AISI 52100 bearing steel. The main objectives are firstly focused on the effect of cutting parameters and coating material on the performances of cutting tools. Secondly, to perform a Multi-objective optimization for minimizing surface roughness (Ra) and maximizing material removal rate by desirability approach. A mathematical model was developed based on the Response Surface Methodology (RSM). ANOVA method was used to quantify the cutting parameters effects on the machining surface quality and the material removal rate. The results analysis shows that the feed rate has the most effect on the surface quality. The effect of coating layers on the surface quality is also studied. It is observed that a lower surface roughness is obtained when using PVD (TiCN-TiN) coated insert when compared with uncoated tool. The values of root mean square deviation and coefficient of correlation between the theoretical and experimental data are also given in this work where the maximum calculated error is 2.65 %.

Abrasive Water Jet Machining is one of the novel nontraditional cutting processes found diverse applications in machining different kinds of difficult-to-machine materials. Process parameters play an important role in finding the economics of machining process at good quality. This research focused on the predictive models for explaining the functional relationship between input and output parameters of AWJ machining process. No single set of parametric combination of machining variables can suggest the better responses concurrently, due to its conflicting nature. Hence, an approach of Multi-objective has been attempted for the best combination of process parameters by modelling AWJM process using of ANN. It served a set of optimal process parameters to AWJ machining process, which shows a development with an enhanced productivity. Wide set of trail experiments have been considered with a broader range of machining parameters for modelling and, then, for validating. The model is capable of predicting optimized responses.

The influence of military-political instability at the state security has special consequences and cannot be ignored. That is why the methods of economic security calculations should be adapted to modern conditions. Significant changes in economic, political, social conditions in Ukraine because of the influence of military events cause the necessity of developing approaches to calculations of economic security level. The article aims at analyzing active methods of calculations of economic security level to adapt their indicators to actual economic circumstances in Ukraine and the world. Indicators of the economic security have been composed of budget, money-credit, foreign exchange, debt, known banking financial market security, banking security. Every component of economic security has factors of war influence, which, as a result, correlates with the integral indicator of economic security. The relevance and indispensability of reinforcement of the economy’s competitiveness on security foundations are substantiated. The authors’ methods of calculation of an integral indicator of economic security have been suggested. A taxonomic indicator is used to measure the level of security. Conclusions regarding the preconditions, capacity, and availability of tendencies of economic security in regions of the country have been made. Strategic priorities of the state policy for reinforcement of economic security have been substantiated.