Aerodynamic shape optimization of the nose of a high-speed train subjected to crosswind conditions

When dealing with the design of a high-speed train, a multiobjective shape optimization problem is formulated, as these vehicles are object of many aerodynamic problems which are known to be in conflict. More mobility involves an increase in both the cruise speed and lightness, and these requirements directly influence the stability and the ride comfort of the passengers when the train is subjected to a side wind. Thus, crosswind stability plays a more relevant role among the aerodynamic objectives to be optimized. An extensive research activity is observed on aerodynamic response in crosswind conditions.

Aerodynamic Optimization of a High-speed Train using Genetic Algorithms

Genetic algorithms (GA) have been used for the minimization of the aerodynamic drag of a train subject to front wind. The significant importance of the external aerodynamic drag on the total resistance a train experiments as the cruise speed is increased highlights the interest of this study. A complete description of the methodology required for this optimization method is introduced here, where the parameterization of the geometry to be optimized and the metamodel used to speed up the optimization process are detailed. A reduction of about a 25% of the initial aerodynamic drag is obtained in this study, what confirms GA as a proper method for this optimization problem. The evolution of the nose shape is consistent with the literature. The advantage of using metamodels is stressed thanks to the information of the whole design space extracted from it. The influence of each design variable on the objective function is analyzed by means of an ANOVA test.

Impact of High-Speed Rail on Tourists' Decisions: Evidence from a Survey Conducted in Paris and in Madrid

The analysis of how tourists select their holiday destinations along with the factors that determine their choices is very important for promoting tourism. In particular, transportation is supposed to have influence on tourists? decissions. The objective of this paper is to investigate more especifically the role of High Speed Rail (HSR) in this choice. Two key tourist destinations in Europe, Paris and Madrid, have been chosen to understand the factors influencing this choice. On the basis of a survey conducted to tourists, we found out that some aspects such as the presence of architectural sites, the quality of promotion of the destination itself, and cultural and social events, have an impact on their choice. However the presence of the HSR system affects the choice of Paris and Madrid as a touristic destination in a different way. For Paris, TGV is considered a real transport mode alternative among tourists who use it quite often. On the other hand, Madrid is chosen by tourists irrespective of the presence of an efficient HSR network. Data collected from the two surveys have been used for a further quantitative analysis. Regression models have been specified and parameters have been calibrated to identify the factors influencing holidaymakers to revisit Paris and Madrid and visit other touristic spots accesible from HSR from these cities.

Gust wind tunnel study on ballast pick-up by high-speed trains

This paper describes the experimental setup, procedure, and results obtained, concerning the dynamics of a body lying on a floor, attached to a hinge, and exposed to an unsteady flow, which is a model of the initiation of rotational motion of ballast stones due to the wind generated by the passing of a high-speed train. The idea is to obtain experimental data to support the theoretical model developed in Sanz-Andres and Navarro-Medina (J Wind Eng Ind Aerodyn 98, 772–783, (2010), aimed at analyzing the initial phase of the ballast train-induced-wind erosion (BATIWE) phenomenon. The experimental setup is based on an open circuit, closed test section, low-speed wind tunnel, with a new sinusoidal gust generator mechanism concept, designed and built at the IDR/UPM. The tunnel’s main characteristic is the ability to generate a flow with a uniform velocity profile and sinusoidal time fluctuation of the speed. Experimental results and theoretical model predictions are in good agreement.

High-resolution microPET imaging of carcinoembryonic antigen-positive xenografts by using a copper-64-labeled engineered antibody fragment

Rapid imaging by antitumor antibodies has been limited by the prolonged targeting kinetics and clearance of labeled whole antibodies. Genetically engineered fragments with rapid access and high retention in tumor tissue combined with rapid blood clearance are suitable for labeling with short-lived radionuclides, including positron-emitting isotopes for positron-emission tomography (PET). An engineered fragment was developed from the high-affinity anticarcinoembryonic antigen (CEA) monoclonal antibody T84.66. This single-chain variable fragment (Fv)-CH3, or minibody, was produced as a bivalent 80 kDa dimer. The macrocyclic chelating agent 1,4,7,10-tetraazacyclododecane-N,N′,N′′, N′′′-tetraacetic acid (DOTA) was conjugated to the anti-CEA minibody for labeling with copper-64, a positron-emitting radionuclide (t1/2 = 12.7 h). In vivo distribution was evaluated in athymic mice bearing paired LS174T human colon carcinoma (CEA positive) and C6 rat glioma (CEA negative) xenografts. Five hours after injection with 64Cu-DOTA-minibody, microPET imaging showed high uptake in CEA-positive tumor (17.9% injected dose per gram ± 3.79) compared with control tumor (6.0% injected dose per gram ± 1.0). In addition, significant uptake was seen in liver, with low uptake in other tissues. Average target/background ratios relative to neighboring tissue were 3–4:1. Engineered antibody fragments labeled with positron-emitting isotopes such as copper-64 provide a new class of agents for PET imaging of tumors.

High-speed polynomial basis multipliers over GF(2(m)) for special pentanomial.

Efficient hardware implementations of arithmetic operations in the Galois field are highly desirable for several applications, such as coding theory, computer algebra and cryptography. Among these operations, multiplication is of special interest because it is considered the most important building block. Therefore, high-speed algorithms and hardware architectures for computing multiplication are highly required. In this paper, bit-parallel polynomial basis multipliers over the binary field GF(2(m)) generated using type II irreducible pentanomials are considered. The multiplier here presented has the lowest time complexity known to date for similar multipliers based on this type of irreducible pentanomials.

High speed image techniques for construction safety net monitoring in outdoor conditions

Póster presentado en SPIE Photonics Europe, Brussels, 16-19 April 2012.

High Speed Rail Passenger Profile in Sun and Beach Tourism Destinations: The Case of Alicante (Spain)

This paper aims to study and highlight the profile of the high speed rail (HSR) passenger in the case of the well-known sun and beach destination of Alicante, located in the Southeast of Spain. This region, which is directly connected with Madrid, differs from others because of its warm and sunny weather. The province is a tourist destination for both Spanish citizens and foreigners. However, the studies on the dynamics of the corridor towards Madrid and Alicante regarding HSR are quite recent and it is not possible to draw final conclusions about its impact on tourist mobility.

High-speed UDP Data Transmission with Multithreading and Automatic Resource Allocation

In this paper a utilization of the high data-rates channels by threading of sending and receiving is studied. As a communication technology evolves the higher speeds are used more and more in various applications. But generating traffic with Gbps data-rates also brings some complications. Especially if UDP protocol is used and it is necessary to avoid packet fragmentation, for example for high-speed reliable transport protocols based on UDP. For such situation the Ethernet network packet size has to correspond to standard 1500 bytes MTU[1], which is widely used in the Internet. System may not has enough capacity to send messages with necessary rate in a single-threaded mode. A possible solution is to use more threads. It can be efficient on widespread multicore systems. Also the fact that in real network non-constant data flow can be expected brings another object of study –- an automatic adaptation to the traffic which is changing during runtime. Cases investigated in this paper include adjusting number of threads to a given speed and keeping speed on a given rate when CPU gets heavily loaded by other processes while sending data.

Evaluation of traffic control devices for rural high-speed maintenance work zones.

Texas Department of Transportation, Research and Technology Transfer Office, Austin