2,082 research outputs found

    Replacing orthometric heights with ellipsoidal heights in engineering surveys

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    Differential Global Positioning System (DGPS) is one of the most frequently used positioning methods in geodesy. The end products of surveying with Global Navigation Satellite Systems (GNSS)are geodetic latitude (ϕ), geodetic longitude (λ) and ellipsoidal height (h) which are obtained with reference to the ellipsoid.  Recent developments in GNSS technology make us to obtain the ellipsoidal height with high accuracy. In engineering practice, orthometric heights (height above sea level) are always used. The orthometric heights are determined by spirit or geodetic leveling. In transforming the GNSS-derived ellipsoidal heights to orthometric heights, it is important to know the separation between the ellipsoidal and the geoid surface. This work investigates the use of ellipsoidal heights in place of orthometric heights for engineering surveys. DGPS observations were carried out to obtain the ellipsoidal heights for a number of points in the study area in Port Harcourt, Nigeria. Orthometric heights for the same set of points were determined using geodetic levelling. The results satisfied third order levelling which is good enough for engineering surveys. http://dx.doi.org/10.4314/njt.v35i4.1

    Analysis of Applying Ultrasonic Frequency on a Desktop FDM Nozzle

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    Fused deposition modeling (FDM) is an Additive Manufacturing (AM) that allows a designer or engineer discloses a desired shape by simply drawing a design on the computer. It is also the most economical AM process. Despite these advantages, it has the biggest drawback that it requires post processing to produce a good surface finish of parts produce. This research studies the application of ultrasonic to a desktop FDM system. The idea is to transmit high vibration from the ultrasonic transducer to the FDM system particularly on the nozzle. However, the idea has yet to be proven. This paper aims to examine whether the FDM nozzle is able to withstand the high vibration transmitted. The project was carried out using a CAD and ANSYS software. The CAD software is used to develop a 3-dimensional model and the ANSYS software is used to perform static and vibration analysis. 20 kHz to 30 kHz and 30 kHz to 40 kHz vibrations were applied. From the results of the analysis, the FDM can stand up to 40 kHz of frequency of vibration to the FDM nozzle. In addition, the lowest Factor of Safety obtained is 18.8975. Thus, it can be concluded that the nozzle of FDM can withstand the high vibration transmitted from the ultrasonic transducer

    Prospects for terahertz imaging the human skin cancer with the help of gold-nanoparticles-based terahertz-to-infrared converter

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    The design is suggested, and possible operation parameters are discussed, of an instrument to inspect a skin cancer tumour in the terahertz (THz) range, transferring the image into the infrared (IR) and making it visible with the help of standard IR camera. The central element of the device is the THz-to-IR converter, a Teflon or silicon film matrix with embedded 8.5 nm diameter gold nanoparticles. The use of external THz source for irradiating the biological tissue sample is presumed. The converter's temporal characteristics enable its performance in a real-time scale. The details of design suited for the operation in transmission mode (in vitro) or on the human skin in reflection mode {in vivo) are specified.Comment: To be published in the proceedings of the FANEM2018 workshop - Minsk, 3-5 June 201

    Neural Network Analysis to Evaluate Ozone Damage to Vegetation Under Different Climatic Conditions

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    Tropospheric ozone (O-3) is probably the air pollutant most damaging to vegetation. Understanding how plants respond to O(3)pollution under different climate conditions is of central importance for predicting the interactions between climate change, ozone impact and vegetation. This work analyses the effect of O(3)fluxes on net ecosystem productivity (NEP), measured directly at the ecosystem level with the eddy covariance (EC) technique. The relationship was explored with artificial neural networks (ANNs), which were used to model NEP using environmental and phenological variables as inputs in addition to stomatal O(3)uptake in Spring and Summer, when O(3)pollution is expected to be highest. A sensitivity analysis allowed us to isolate the effect of O-3, visualize the shape of the O-3-NEP functional relationship and explore how climatic variables affect NEP response to O-3. This approach has been applied to eleven ecosystems covering a range of climatic areas. The analysis highlighted that O(3)effects over NEP are highly non-linear and site-specific. A significant but small NEP reduction was found during Spring in a Scottish shrubland (-0.67%), in two Italian forests (up to -1.37%) and during Summer in a Californian orange orchard (-1.25%). Although the overall seasonal effect of O(3)on NEP was not found to be negative for the other sites, with episodic O(3)detrimental effect still identified. These episodes were correlated with meteorological variables showing that O(3)damage depends on weather conditions. By identifying O(3)damage under field conditions and the environmental factors influencing to that damage, this work provides an insight into O(3)pollution, climate and weather conditions.Peer reviewe

    HOSPICIJ-POTREBA HUMANOG DRUŠTVA

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    Hrvatsko zakonodavstvo i regulativa palijativne skrbi imaju postavljene neke smjernice za razvoj u Republici Hrvatskoj. Međutim, da uhvatimo korak s razvijenim zemljama treba puno toga pravno i organizacijski urediti. Imamo znanje, imamo volju , imamo svijest nesebičnog djelovanja, ali nemamo financijske mogućnosti u ovom trenutku.O palijativnoj skrbi svaki pojedinac počinje razmišljati tek onda kada mu se razboli član njegove obitelji. Da smo u stanju podići ovu djelatnost u prioritete, našla bi se i sredstva za nju. Da bismo mogli iskoristiti znanje koje imamo treba odmah djelovati. To neće biti jednostavan proces, no u svijetu postoji puno modela i primjera, pa bi se uz iskustvo drugih, naš stručni kadar, te djelovanje na fleksibilnost hrvatske birokracije, okolnosti mogle promijeniti u pozitivnom smislu. Ne zbog nas, ali možda i za nas

    Saliva Proteins of Vector Culicoides Modify Structure and Infectivity of Bluetongue Virus Particles

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    Bluetongue virus (BTV) and epizootic haemorrhagic disease virus (EHDV) are related orbiviruses, transmitted between their ruminant hosts primarily by certain haematophagous midge vectors (Culicoides spp.). The larger of the BTV outer-capsid proteins, ‘VP2’, can be cleaved by proteases (including trypsin or chymotrypsin), forming infectious subviral particles (ISVP) which have enhanced infectivity for adult Culicoides, or KC cells (a cell-line derived from C. sonorensis). We demonstrate that VP2 present on purified virus particles from 3 different BTV strains can also be cleaved by treatment with saliva from adult Culicoides. The saliva proteins from C. sonorensis (a competent BTV vector), cleaved BTV-VP2 more efficiently than those from C. nubeculosus (a less competent / non-vector species). Electrophoresis and mass spectrometry identified a trypsin-like protease in C. sonorensis saliva, which was significantly reduced or absent from C. nubeculosus saliva. Incubating purified BTV-1 with C. sonorensis saliva proteins also increased their infectivity for KC cells ∼10 fold, while infectivity for BHK cells was reduced by 2–6 fold. Treatment of an ‘eastern’ strain of EHDV-2 with saliva proteins of either C. sonorensis or C. nubeculosus cleaved VP2, but a ‘western’ strain of EHDV-2 remained unmodified. These results indicate that temperature, strain of virus and protein composition of Culicoides saliva (particularly its protease content which is dependent upon vector species), can all play a significant role in the efficiency of VP2 cleavage, influencing virus infectivity. Saliva of several other arthropod species has previously been shown to increase transmission, infectivity and virulence of certain arboviruses, by modulating and/or suppressing the mammalian immune response. The findings presented here, however, demonstrate a novel mechanism by which proteases in Culicoides saliva can also directly modify the orbivirus particle structure, leading to increased infectivity specifically for Culicoides cells and, in turn, efficiency of transmission to the insect vector
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