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A numerical method for shape optimisation in forging is presented. The goal of the optimisation is to eliminate work‐piece defects that may arise during the forging process. A two‐dimensional finite element code has been developed for the simulation of the mechanical process. The material is incompressible and it follows the Norton‐Hoff law. To deal with contact constraint the velocity projection algorithm is used. The optimisation process is conducted using a genetic algorithm supported by an elitist strategy. A new genetic operator called adaptive mutation has been developed to increase the efficiency of the search. The developed scheme is used to design optimal preform shapes for several axisymmetric examples. Continuous and discrete design variables are considered. The objective function of the optimisation problem is associated with the quality of the final product. Comparing the obtained optimal results with the literature validates the proposed optimisation method.

An optimisation method for design of intermediate die shapes needed in some forging operations is presented. The basic problem consists of finding an optimal two‐step forging sequence by automatically designing the shape of the preforming tools. The optimisation problem is defined based on an inverse formulation. The objective function of the optimisation problem is a function describing the quality of the obtained part by measuring the die underfill. The finite element method is used to simulate the forging problem. The optimisation method is based on a modified sequential unconstrained minimisation technique and a gradient method. The sensitivity‐dependent algorithm requires computing the derivatives of the objective function with respect to the design variables defining the preform shapes. A direct differentiation method has been developed for this purpose. The optimisation scheme is demonstrated with two axisymmetric forging examples in which optimal preform dies are obtained.

The aim of this paper is to analyze and compare the effect of different hotel characteristics and room attributes on room rates of hotels in the cities of Lisbon and Porto, the capital and second most important city in Portugal.

Using the hedonic pricing method, hotel characteristics are decomposed and analyzed, giving us the perception of the impact of each hotel attributes on the room rates and the people’s willingness to pay for this. Ordinary least square regression analysis was applied to the hedonic price model to find which variables could explain differences in the hotel room rates in Lisbon and Porto.

The results suggest that in Lisbon and in Porto, a number of common characteristics have significant effects on consumer willingness to pay for a stay in a hotel as star rating, consumer rating and the room size. In Porto, the existence of a fitness centre and in Lisbon, the distance to the city centre are also attributes that create a premium in room rates.

The knowledge of the most valued characteristics by consumers is an important tool for hotel managers to define a price strategy. Also important is the knowledge of the attributes that provide more added value for consumers as these should be taken into account in new investment decisions.

This study highlights the implications of the way one defines and measures qualitative hotel characteristics in hedonic pricing. Although the hedonic method has been applied in several studies, to our knowledge, in Portugal, there are few studies applied only to hotel room rates, and there are no studies comparing hotel room rates in different Portuguese cities. Moreover, the research highlights the critical role of a proper definition and measurement of the variables in hedonic pricing in general and the hotel star in particular.

The purpose of this paper is to present a shape optimization technique for powder forming processes based on the genetic algorithm approach. The genetic algorithm is employed to optimize the geometry of component based on a fixed‐length vector of design variables representing the changes in nodal coordinates. The technique is used to obtain the desired optimal compacted component by changing the boundaries of component and verifying the prescribed constraints.

The numerical modeling of powder compaction simulation is applied based on a large deformation formulation, powder plasticity behavior, and frictional contact algorithm. A Lagrangian finite element formulation is employed for large powder deformations. A cap plasticity model is used in numerical simulation of nonlinear powder behavior. The influence of powder‐tool friction is simulated by the use of penalty approach in which a plasticity theory of friction is incorporated to model sliding resistance at the powder‐tool interface.

Finally, numerical examples are analyzed to demonstrate the feasibility of the proposed optimization algorithm for designing powder components in the forming process of powder compaction.

A shape optimization technique is presented for powder forming processes based on the genetic algorithm approach.

A strong anti-immigrant and anti-refugee sentiment permeates the political discourse in the United States and many Western European countries. This political discourse, along with policies designed to limit immigration, is likely to influence the academic motivation of students from immigrant groups. In this chapter, we consider how anti-immigrant sentiment in the host countries may affect the motivation and achievement of immigrant and refugee students. Specifically, we apply findings from research examining stress and anxiety, belonging, identity, teacher expectancies, and stereotype threat to speculate about how these motivational factors may be affected by anti-immigrant rhetoric. Next, we use Maehr’s (1984) theory of personal investment (PI) as a framework for integrating the various components of motivation that can be applied to the current plight of immigrant and refugee students. The chapter concludes with a brief discussion about the steps we can take, both at the personal and the policy levels, to counteract the hostile political discourse and promote higher levels of PI in education among immigrant and refugee students.

This work intends to evaluate experimentally the ratcheting behaviour of AM MS300. Furthermore, cyclic plasticity modelling (modified Abdel-Karim and Ohno model) is examined as a means of predicting ratcheting.

Uniaxial stress-controlled cyclic loading histories were utilised to evaluate ratcheting for Maraging Steel 300 (MS300) fabricated via laser powder bed fusion (LPBF) additive manufacturing (AM). Heat-treated and as-built AM and conventionally manufactured (CM) MS300 coupons were tested at room temperature, under constant and incrementally variable stress amplitude and mean stress. Two sets of AM test coupons were used, printed at horizontal and vertical built orientation. The AM material ratcheting was predicted via constitutive modelling and numerical simulation. The Abdel-Karim and Ohno cyclic plasticity model was modified by introducing a memory surface, to improve ratcheting prediction.

The hysteresis stress–strain response and low cycle fatigue (LCF) life were obtained from the different loading histories. Both the AM and CM MS300 exhibited an accumulation of axial strain (ratcheting) for all tests, attributed to the application of non-zero mean stress. The AM MS300 has demonstrated a higher ratcheting accumulation rate than the CM material. The achieved agreement between the numerical results of the new model and the experimental data offers an indication on the suitability and the robustness of this model.

The ratcheting behaviour of the AM MS300 material has been characterised for the first time in the published literature, for a variety of loading histories selected. A modified Abdel-Karim and Ohno plasticity model has been developed to account for the ratcheting performance of this material.

In the finite element analysis of a hot forging process, it is difficult to design an optimal preform because of highly nonlinear characteristics of design variables. In this paper, a new preform design method which can reduce the forming load and the die wear by removing the flash is developed and applied to the pre form design of a piston.

After finite element analyses of hot forging processes, if the final product is found to have excessive flash and cause high die wear, a new preform design technique, so‐called iterative preform design technique is applied to obtain an optimal preform design. From the results of FE simulations, a boundary region at the outlet of the flash is first selected. Then, by tracing the section along the deformation path to the initial billet, it is possible to obtain a mapped section boundary in the initial billet. After updating the initial shape by removing the exterior region of the mapped section boundary, a finite element simulation is carried out with the updated initial shape. Iterations should be continued until a desired result is obtained.

It has been confirmed that the proposed preform design technique has a negligible effect on the initial forgeability of the workpiece. It is expected that the tool life will be increased, because the forming load and die wear are reduced as the number of iterations are increased. Moreover, because the preform design reduces the flash, it thereby reduces the waste of material.

In the 3D finite element analysis of a hot forging process, several optimal preform design techniques have been developed. However, it is difficult to use the techniques in general problems because it is difficult to formulate cost functions, which mainly depend on the experience and physical insight of the designer. In addition, tremendous time is consumed in optimizing a problem as a large number of iterations are required in minimizing the objective function. The proposed preform design technique is simple enough to apply to general hot forging problems involving excessive flash. The proposed preform design technique is an offline method and easy to apply to any other analysis program, including commercial programs.

The aim of this chapter is to provide the readers with a brief background to the characteristics of tourism and a synoptic presentation of the main trends in tourism markets and challenges that tourism businesses should deal with.

A literature review was conducted on the relevant trends that can affect the management and marketing of tourism businesses. Micro case studies were also presented as practical examples of how tourism businesses have adapted to trends.

This chapter highlights the specific characteristics of the tourism industry, as well as the trends in the market/business environment. Tourism businesses need to remain aware of trends and find solutions to adapt their services and activities to take advantage of them.

This chapter is explorative in nature because it has made used of extant literature.

Tourism entrepreneurs are encouraged to stay abreast of changes in the business environment. Some of the examples provided may only be applicable in the short run but other examples have long-term impact. Valuable solutions are provided for consideration.

This chapter analyses several trends affecting the tourism industry from management and marketing perspectives. This analysis gives a better understanding of how these trends specifically affect tourism. This chapter highlights the importance of monitoring the trends and their evolution in the various markets.