The Spatial Pattern of FDI: Some Testable Hypotheses

This paper is a simple extension of the standard FDI model of Markusen and Horstmann (1992). This latter predicts firms would supply nearby markets with exports but far away markets with FDI. Nevertheless, this does not match the spatial pattern in the data for many home nations and industries. We propose a model with heterogeneous firms where the spatial pattern of FDI depends upon distance-linked communications costs as well as trade costs; the resulting model lines up both with the aggregate knowledge-capital model evidence and the firm-level evidence of Helpman-Melitz-Yeaple, while still allowing individual firms to engage in FDI in nearby markets while supplying distant markets via exports.

Firm Heterogeneity, Rules of Origin and Rules of Cumulation

We analyse the impact of relaxing rules of origin (ROOs) in a simple setting with heterogeneous firms that buy intermediate inputs from domestic and foreign sources. In particular, we consider the impact of switching from bilateral to diagonal cumulation when using preferences (instead of paying the MFN tariff) involving the respect of rules of origin. We find that relaxing the restrictiveness of the ROOs leads the least productive exporters to stop exporting. The empirical part confirms these results. We use the most recent techniques developed by Helpman, Melitz and Rubinstein (2007) on highly disaggregated data (HS6 digit) to analyse the effects of the introduction of the Pan-European Cumulation System (PECS). We find that PECS reverses the negative impact of strict ROOs on intermediate trade which turns positive as a consequence of introducing diagonal ROCs.Intermediate goods, Rules of origin, Rules of cumulation, Firm heterogeneity, Gravity.

Design, implementation, and validation of a benchmark generator for combinatorial interaction testing tools

Combinatorial testing is a widely adopted technique for efficiently detecting faults in software. The quality of combinatorial test generators plays a crucial role in achieving effective test coverage. Evaluating combinatorial test generators remains a challenging task that requires diverse and representative benchmarks. Having such benchmarks might help developers to test their tools, and improve their performance. For this reason, in this paper, we present BenCIGen, a highly configurable generator of benchmarks to be used by combinatorial test generators, empowering users to customize the type of benchmarks generated, including constraints and parameters, as well as their complexity. An initial version of such a tool has been used during the CT-Competition, held yearly during the International Workshop on Combinatorial Testing. This paper describes the requirements, the design, the implementation, and the validation of BenCIGen. Tests for the validation of BenCIGen are derived from its requirements by using a combinatorial interaction approach. Moreover, we demonstrate the tool's ability to generate benchmarks that reflect the characteristics of real software systems. BenCIGen not only facilitates the evaluation of existing generators but also serves as a valuable resource for researchers and practitioners seeking to enhance the quality and effectiveness of combinatorial testing methodologies

The tilted-coil concept for advanced tokamak devices

The implications of the adoption of a tokamak’s toroidal field coil characterized by tilting in the azimuthal direction are investigated. The major advantage introduced by tilted coils is that of a drastic reduction over most of the coil section of the electromagnetic forces. As a beneficial side-effect, the tilted coils generate a poloidal field, in addition to the toroidal field. The former advantage allows for a notable simplification of the machine layout, while the poloidal flux generated during the current rise, when used in conjunction with the conventional central solenoid, allows for discharges of much longer duration with respect to those obtainable in tokamaks with conventional (non-tilted legs) coils

Rail Diagnostics Based on Ultrasonic Guided Waves: An Overview

Rail tracks undergo massive stresses that can affect their structural integrity and produce rail breakage. The last phenomenon represents a serious concern for railway management authorities, since it may cause derailments and, consequently, losses of rolling stock material and lives. Therefore, the activities of track maintenance and inspection are of paramount importance. In recent years, the use of various technologies for monitoring rails and the detection of their defects has been investigated; however, despite the important progresses in this field, substantial research efforts are still required to achieve higher scanning speeds and improve the reliability of diagnostic procedures. It is expected that, in the near future, an important role in track maintenance and inspection will be played by the ultrasonic guided wave technology. In this manuscript, its use in rail track monitoring is investigated in detail; moreover, both of the main strategies investigated in the technical literature are taken into consideration. The first strategy consists of the installation of the monitoring instrumentation on board a moving test vehicle that scans the track below while running. The second strategy, instead, is based on distributing the instrumentation throughout the entire rail network, so that continuous monitoring in quasi-real-time can be obtained. In our analysis of the proposed solutions, the prototypes and the employed methods are described

Potential performance of environmental friendly application of ORC and Flash technology in geothermal power plants

The successful exploitation of geothermal energy for power production relies on to the availability of nearly zero emission and efficient technologies, able to provide flexible operation. It can be realized with the binary cycle technology. It consists of a closed power cycle coupled to a closed geothermal loop, whereby the closed power cycle is generally accomplished by means of an organic Rankine cycle (in a few cases the Kalina cycle has been adopted). The confinement of the geothermal fluid in a closed loop is an important advantage from the environmental point of view: possible pollutants contained in the geothermal fluid are not released into the ambient and are directly reinjected underground. Although a well-established technology in the frame of geothermal applications, the adoption of the binary cycle technology is at the moment typically confined to the exploitation of medium-low temperature liquid geothermal reservoirs, generally between 100-170°C. The important advantages of the binary cycle technology from the environmental point of view suggest nevertheless that it is worthwhile to investigate whether the application range could be extended to higher temperature reservoirs, and up to which extent. Moreover, the paper investigates the effect of an increasing CO2content in the geothermal fluid. The paper compares in a convenient high temperature range of the geothermal source the performance of a properly optimized geothermal ORC plant, with the performance of a modified flash plant, whereby the geothermal steam enters a turbine, and the CO2stream is separated, compressed and finally reinjected. An environmentally friendly working fluid, recently introduced in the market, is considered in the ORC optimization process. The performance comparison will involve the assessment of plant net power. As far as the calculations are concerned, the geothermal fluid is assumed to be a mixture of water and possibly CO2. The auxiliary power consumption is properly accounted for: beyond cooling auxiliaries, a submersible well pump for the ORC plant and a gas compressor for the reinjection of the non-condensable gases in the flash plant are considered

THERMODYNAMIC ORC CYCLE DESIGN OPTIMIZATION FOR MEDIUM-LOW TEMPERATURE ENERGY SOURCES

In the large spectrum of organic fluids suitable for Rankine cycles, a fluid that is already wellknown and available on industrial scale but currently excluded from this kind of application has been selected. This choice is due to the remarkable characteristics of the fluid, such as its high molecular weight, good thermal stability, non-flammability, and atoxicity. Compared to those fluids nowadays common in the ORC market, its thermodynamic properties and fluid dynamic behavior lead to a peculiar configuration of the cycle: • Supercritical cycle, when heat input is at medium-high temperature; • Massive regeneration, to obtain higher efficiency; • Low specific work of the turbine; • Relatively high volumetric expansion ratio and relatively low absolute inlet volumetric flow; Accordingly, an innovative cycle design has been developed, including a once-through Hairpin primary heat exchanger and a multi-stage radial outflow expander. This last innovative component has been designed to get the best performance with the chosen fluid: • The high inlet/outlet volumetric flow ratio is well combined with the change in cross section across the radius; • Compared to an axial turbine, the lower inlet volumetric flow is compensated by higher blades at the first stage. It is feasible thanks to the change in section available along the radius, so that there is no need for partial admission; • The prismatic blade leads to constant velocity diagrams across the blade span; • It minimizes tip leakages and disk friction losses, due to the single disk / multi-stage configuration; • The intrinsical limit of a radial outflow expander to develop high enthalpy drop is not relevant for this cycle, presenting itself a very low enthalpy drop. Moreover the tip speed is limited by the low speed of sound and consequently this kind of expander suits well with this cycle arrangement. The results of this study, conducted through thermodynamic simulations, CFD, stress analysis and economic optimization show an ORC system that reaches high efficiencies, comparable to those typical of existing system

Zero Emission Geothermal Flash Power Plant

The successful exploitation of geothermal energy for power production relies on the availability of nearly zero emission and efficient technologies. Two zero emission flash plant layouts, with full reinjection of the geothermal fluid (non-condensable gas included), are considered. This paper focusses on the CO2issue, and therefore only the carbon dioxide is considered as non-condensable gas present in the geothermal fluid; the CO2 flow is separated, compressed, and reinjected with the geothermal fluid. Both the reservoir and the power plant are simulated. A first scheme of plant presents a conventional layout in which the CO2is separated and compressed after the condenser. The second scheme presents a plant layout that allows the separation of the CO2at higher pressure with respect to the conventional layout, thus reducing the requested power consumption. The conventional plant scheme performs always better at higher temperature and at lower concentration of CO2. The new layout results better for low temperature and higher gas content