50,100 research outputs found
Virtual testing environment tools for railway vehicle certification
This paper describes the work performed in Work Package 6 of the European project DynoTRAIN. Its task was to investigate the effects that uncertainties present within the track and running conditions have on the simulated behaviour of a railway vehicle. Methodologies and frameworks for using virtual simulation and statistical tools, in order to reduce both the cost and time required for the certification of new or modified railway vehicles, were proposed. In particular, the project developed a virtual test track (VTT) toolkit that is capable of both generating a series of test tracks based on measurements, which can be used in vehicle virtual testing using computer simulation models, and also automatically handling the output results. The toolkit is compliant with prEN14363: 2013. The VTT was used as an experimental tool to analyse cross-correlations between track data (input) and matching vehicle response (output) based on data recorded using a test train. This paper discusses the issues encountered in the process and suggests avenues for future developments and potential use in the context of European cross-acceptance. The VTT offers benefits to the areas of design development and regulatory certification
A Laser Frequency Comb System for Absolute Calibration of the VTT Echelle Spectrograph
A wavelength calibration system based on a laser frequency comb (LFC) was
developed in a co-operation between the Kiepenheuer-Institut f\"ur
Sonnenphysik, Freiburg, Germany and the Max-Planck-Institut f\"ur Quantenoptik,
Garching, Germany for permanent installation at the German Vacuum Tower
Telescope (VTT) on Tenerife, Canary Islands. The system was installed
successfully in October 2011. By simultaneously recording the spectra from the
Sun and the LFC, for each exposure a calibration curve can be derived from the
known frequencies of the comb modes that is suitable for absolute calibration
at the meters per second level. We briefly summarize some topics in solar
physics that benefit from absolute spectroscopy and point out the advantages of
LFC compared to traditional calibration techniques. We also sketch the basic
setup of the VTT calibration system and its integration with the existing
echelle spectrograph.Comment: 9 pages, 2 figures; Solar Physics 277 (2012
Distance learning plan for the Defense Finance and Accounting Service (DFAS): a study for the Defense Business Management University (DBMU)
This thesis analyzes the requirements and design considerations of a video teletraining (VIT) delivery system for 25 Defense Finance and Accounting Service (DFAS) centers located throughout the continental United States. Current DFAS VTT capabilities are reviewed and included. The study's sponsor, The Defense Business Management University (DBMU). bas been tasked by the DoD Comptroller to implement a training program for these centers. The DBMU has identified VTT as an extremely cost-effective option for training personnel at these 25 DFAS satellite adivities. The study focuses on current VTT technologies-both in industry and in the DoD. Basic VTT concepts are presented, evolving VTT standards are discussed, existing DoD VIT infrastructures are outlined, and problem areas such as system interoperability are explored. The study presents recommendations for an immediale DFAS VTT implementation plan using available DoD one-way/two-way satellite and/or two-way/two-way terrestrial distance education capabilities. This thesis also presents a recommendation for integration of a long term V1T network broadacast system including a single site program origination studio.http://archive.org/details/distancelearning1094543029U.S. Naval Reserve (USNR) author.;U.S. Navy (USN) authorApproved for public release; distribution is unlimited
Antimicrobial properties of berries
Berries, especially their antimicrobial properties, have been studied intensively at VTT over the past ten years in several research projects. In these in vitro studies phenolic berry extracts of common Nordic berries selectively inhibited the growth of harmful bacteria and human intestinal pathogens, without affecting the growth of beneficial lactic acid bacteria
Mucosal Immunization Induces a Higher Level of Lasting Neutralizing Antibody Response in Mice by a Replication-Competent Smallpox Vaccine: Vaccinia Tiantan Strain
The possible bioterrorism threat using the variola virus, the causative agent of smallpox, has promoted us to further investigate the immunogenicity profiles of existing vaccines. Here, we study for the first time the immunogenicity profile of a replication-competent smallpox vaccine (vaccinia Tiantan, VTT strain) for inducing neutralizing antibodies (Nabs) through mucosal vaccination, which is noninvasive and has a critical implication for massive vaccination programs. Four different routes of vaccination were tested in parallel including intramuscular (i.m.), intranasal (i.n.), oral (i.o.), and subcutaneous (s.c.) inoculations in mice. We found that one time vaccination with an optimal dose of VTT was able to induce anti-VTT Nabs via each of the four routes. Higher levels of antiviral Nabs, however, were induced via the i.n. and i.o. inoculations when compared with the i.m. and s.c. routes. Moreover, the i.n. and i.o. vaccinations also induced higher sustained levels of Nabs overtime, which conferred better protections against homologous or alternating mucosal routes of viral challenges six months post vaccination. The VTT-induced immunity via all four routes, however, was partially effective against the intramuscular viral challenge. Our data have implications for understanding the potential application of mucosal smallpox vaccination and for developing VTT-based vaccines to overcome preexisting antivaccinia immunity
Motion Planning for Variable Topology Trusses: Reconfiguration and Locomotion
Truss robots are highly redundant parallel robotic systems that can be
applied in a variety of scenarios. The variable topology truss (VTT) is a class
of modular truss robots. As self-reconfigurable modular robots, a VTT is
composed of many edge modules that can be rearranged into various structures
depending on the task. These robots change their shape by not only controlling
joint positions as with fixed morphology robots, but also reconfiguring the
connectivity between truss members in order to change their topology. The
motion planning problem for VTT robots is difficult due to their varying
morphology, high dimensionality, the high likelihood for self-collision, and
complex motion constraints. In this paper, a new motion planning framework to
dramatically alter the structure of a VTT is presented. It can also be used to
solve locomotion tasks that are much more efficient compared with previous
work. Several test scenarios are used to show its effectiveness. Supplementary
materials are available at https://www.modlabupenn.org/vtt-motion-planning/.Comment: 20 pages, 36 figure
Impact of travel time constraints on taste heterogeneity and non-linearity in simple time-cost trade-offs
Discrete choice models are a key technique for estimating the value of travel time (VTT). Often, stated choice data are used in which respondents are presented with trade-offs between travel time and travel cost and possibly additional attributes. There is a clear possibility that some respondents experience time constraints, leaving some of the presented options unfeasible. A model not incorporating information on these constraints would explain choices for faster and more expensive options as an indication that those respondents have a higher VTT when in reality they may be forced to select the more expensive option as a result of their personal constraints. This paper puts forward the hypothesis that this can have major impacts on findings in terms of heterogeneity in VTT measures. This paper examines via simulation the bias in VTT estimates and especially preference heterogeneity when such constraints are (not) accounted for. Empirical evidence is provided that preference heterogeneity is confounded with the travel budget impact on the availabilities of alternatives, and it is shown that there is a risk of producing biased estimates for appraisal VTT if studies do not explicitly model choice set formation. The inclusion of an opt-out alternative could be an effective measure to reduce the bias. This paper also explores the potential use of non-linear functional forms to capture the time budget impacts
Heavily Irradiated N-in-p Thin Planar Pixel Sensors with and without Active Edges
We present the results of the characterization of silicon pixel modules
employing n-in-p planar sensors with an active thickness of 150
m, produced at MPP/HLL, and 100-200 m thin active
edge sensor devices, produced at VTT in Finland. These thin sensors are
designed as candidates for the ATLAS pixel detector upgrade to be operated at
the HL-LHC, as they ensure radiation hardness at high fluences. They are
interconnected to the ATLAS FE-I3 and FE-I4 read-out chips. Moreover, the
n-in-p technology only requires a single side processing and thereby it is a
cost-effective alternative to the n-in-n pixel technology presently employed in
the LHC experiments. High precision beam test measurements of the hit
efficiency have been performed on these devices both at the CERN SpS and at
DESY, Hamburg. We studied the behavior of these sensors at different bias
voltages and different beam incident angles up to the maximum one expected for
the new Insertable B-Layer of ATLAS and for HL-LHC detectors. Results obtained
with 150 m thin sensors, assembled with the new ATLAS FE-I4 chip
and irradiated up to a fluence of
410, show that they are
excellent candidates for larger radii of the silicon pixel tracker in the
upgrade of the ATLAS detector at HL-LHC. In addition, the active edge
technology of the VTT devices maximizes the active area of the sensor and
reduces the material budget to suit the requirements for the innermost layers.
The edge pixel performance of VTT modules has been investigated at beam test
experiments and the analysis after irradiation up to a fluence of
510 has been performed
using radioactive sources in the laboratory.Comment: Proceedings for iWoRiD 2013 conference, submitted to JINS
Factors affecting the fermentation process of Vietnamese traditional wine ("men la" wine) using "Ba Nang" wine starter
“Men la” wine is a traditional wine product of the upland people in Vietnam. The wine is of the cultural essence of the nation, reflecting the current trend of one village one product (OCOP). The "Ba Nang" wine starters are usually made from sticky rice and local herbs. In fact, the use of herbs in traditional wine production has become popular. However, the traditional methods used by the local producers are not standardized. The quality of the wines produced is therefore not stable and wine producers resort to laborious trials and personal experience. The aim of this study was to examine the factors affecting the fermentation process in the production of “Men la” wine using the wine starters of the Van Kieu people in Da Ban, Ba Nang commune, Dakrong district, Quang Tri province, Vietnam. The ratio of yeast to rice, solid fermentation time, temperature, and time of liquid fermentation, as well as some biochemical criteria, were investigated to determine the best parameters for "Men la" wine production. The results showed that the optimal parameters for obtaining the highest quality of wine were: a mixture ratio of wine starter and whole rice of 8g: 1000g; solid fermentation for 4 days at 30 – 32oC; and fermentation for 7 days at 25oC with a ratio of rice ingredients and water of 1:2. The final product contained 4.952% of total sugar, 0.08% of reducing sugar, 0.315% acid, 0.104 g/L amino acid, and 10.61g/100mL of ethanol. The analysis did not detect methanol in the distilled wine products. The finished wine produced on a laboratory scale had a sweet taste equivalent to that of wine, with a flavor that was thought to be superior to the local wine. The alcoholic fermentation time was shortened by 2 days compared with local wine. The resultant "Men la" wine met the National Technical Regulations for alcoholic beverage products (QCVN 6-3:2010/BYT). 
- …