14,553 research outputs found
The Covenant on Human Rights
This project began with a microprocessor platform developed by two master’s students: Albert López and Francisco Javier Sánchez. Their platform was designed as a gateway for sensing devices operating in the 868 MHz band. The platform consists of a Texas Instruments MSP430F5437A microcontroller and a Microchip ENC28J60 Ethernet cont roller connected to the MSP430 processor by a Serial Peripheral Interface. Javier Lara Peinado implemented prototype white space sensors using the platform developed by the earlier two students. As part of his effort, he partially implemented a Trivial File Transfer Protocol (TFTP) system for loading programs in to the flash memory of the microcontroller using Microchip’s TCP/IP stack. However, he was not successful in loading programs into the flash as the TFTP transfer got stuck at the first block. The first purpose of this project was to find and fix the error(s) in the TFTP loading of programs into the MSP430’s flash memory. The second purpose of this project was to evaluate Microchip’s TCP/IP stack in depth. This report describes measurements of UDP transmission rates. Additionally, the TFTP processing rate is measured and the TFTP program loading code is documented. The report concludes with suggestions for possible improvements of this system.Projektet startade med en mikroprocessor-plattform som utvecklades av två masterstudenter: Albert López och Francisco Javier Sánchez. Deras plattform var utformad som en inkörsport för avkänning av apparater som arbetar i 868 MHz-bandet. Plattformen består av en Texas Instruments MSP430F5437A mikrokontroller och en Microchip ENC28J60 Ethernet controller ansluten till MSP430-processor med en SPI-gränssnitt (Serial Peripheral Interface). Javier Lara Peinado genomförde prototypvitt utrymme sensoreranvända plattformen som utvecklades av de två tidigare nämnda studenter. Som en del av sitt arbete genomförde handelvis ett Trivial File Transfer Protocol (TFTP) system för lastning program i flashminne mikrokontroller med hjälp av Microchips TCP / IP-stack. Men han var inte framgångsrik i lastning program i flash som TFTP-överföringen fastnade vid det första blocket. Det första syftet för detta projekt var att hitta och åtgärda felet(er) i TFTP laddning av program i MSP430 flashminne. Det andra syftet för detta projekt var att utvärdera Microchips TCP/IP- stack på djupet. I denna rapport beskrivs mätningar av UDP överföringshastighet. Dessutom mäts TFTP bearbetningshastighet och TFTP programladdningskoden dokumenteras. Rapporten avslutas med förslag på möjliga förbättringar av systemet.Project for IK2553QC 20140702</p
Performance of textured carbon on copper electrode multistage depressed collectors with medium-power traveling wave tubes
Performance of multistage depressed collectors (MDCs) using textured carbon on copper substrate electrode surfaces was evaluated in conjunction with medium-power traveling wave tubes (TWTs). The MDC and TWT overall efficiencies for these electrodes were measured and compared with those obtained with the same TWT and a copper electrode MDC of identical design. Long-term stability of the carbon-coated copper electrode surfaces was investigated by periodic evaluation of TWT-MDC performance over an extended period of continuous wave (CW) operation. Application of textured carbon coating on copper MDC electrode surfaces produced a 13% improvement in both MDC and TWT overall efficiencies for the TWT-MDC tests. During 1600 hr of CW operation with a medium power TWT, no significant changes in MDC performance were noted. This indicated good stability of the textured carbon electrode surfaces. This stability was confirmed by scanning electron microscope examinations of the electrode surfaces before assembly of the MDC and after completion of the test program
Vesicular stomatitis virus glycoprotein is necessary for H-2-restricted lysis of infected cells by cytotoxic T lymphocytes
Vesicular stomatitis virus (VSV) elicited cytotoxic thymus-derived lymphocytes (CTLs) in mice of the BALB/c and three congenic strains (BALB.b, BALB.k, BALB.HTG). CTL lysis of VSV-infected fibroblasts from the four strains was restricted by the target cells' major histocompatibility complex (H-2). Target cells were also infected with two temperature-sensitive mutants of VSV, tsM and tsG in which, respectively, the viral matrix protein and glycoprotein are not expressed at 39 degrees (restrictive temperature) on the infected cell's surface membrane. At the restrictive temperature, cells infected with wild-type VSV or tsM were lysed by CTLs, but cells infected with tsG were not. The requirement for the glycoprotein on the target cell was also evident from the ability of antisera to the glycoprotein to block completely CTL lysis of VSV-infected cells
Metal Chalcogenide Clusters with Closed Electronic Shells and the Electronic Properties of Alkalis and Halogens
Clusters with filled electronic shells and a large gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) are generally energetically and chemically stable. Enabling clusters to become electron donors with low ionization energies or electron acceptors with high electron affinities usually requires changing the valence electron count. Here we demonstrate that a metal cluster may be transformed from an electron donor to an acceptor by exchanging ligands while the neutral form of the clusters has closed electronic shells. Our studies on Co6Te8(PEt3),(CO) (m + n = 6) clusters show that Co6Te8(PEt3)(6) has a closed electronic shell and a low ionization energy of 4.74 eV, and the successive replacement of PEt3 by CO ligands ends with Co6Te8(CO)(6) exhibiting halogen-like behavior. Both the low ionization energy Co6Te8(PEt3)(6) and high electron affinity Co6Te8(CO)(6) have closed electronic shells marked by high HOMO-LUMO gaps of 1.24 and 1.39 eV, respectively. Further, the clusters with an even number of ligands favor a symmetrical placement of ligands around the metal core
BIOECONOMICS OF REGULATING NITRATES IN GROUNDWATER: TAXES, QUANTITY RESTRICTIONS, AND POLLUTION PERMITS
Soil specific, chance constrained, dynamic models of agricultural production and nitrate leaching are developed to assess the impacts of nitrogen fertilizer taxes, quantity restrictions on fertilizer or leachate, and leachate permits. A programming model uses the solutions of these bioeconomic models to determine regional impacts of the regulations.Land Economics/Use, Research Methods/ Statistical Methods,
Cosmological-parameter determination with microwave background maps
The angular power spectrum of the cosmic microwave background (CMB) contains information on virtually all cosmological parameters of interest, including the geometry of the Universe (Ω), the baryon density, the Hubble constant (h), the cosmological constant (Λ), the number of light neutrinos, the ionization history, and the amplitudes and spectral indices of the primordial scalar and tensor perturbation spectra. We review the imprint of each parameter on the CMB. Assuming only that the primordial perturbations were adiabatic, we use a covariance-matrix approach to estimate the precision with which these parameters can be determined by a CMB temperature map as a function of the fraction of sky mapped, the level of pixel noise, and the angular resolution. For example, with no prior information about any of the cosmological parameters, a full-sky CMB map with 0.5° angular resolution and a noise level of 15 μK per pixel can determine Ω, h, and Λ with standard errors of ±0.1 or better, and provide determinations of other parameters which are inaccessible with traditional observations. Smaller beam sizes or prior information on some of the other parameters from other observations improves the sensitivity. The dependence on the underlying cosmological model is discussed
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