Autor: Silva, L.P. - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Spatial analysis of vegetal cover and sediment yield in Tapacura river catchment based on remote sensing and GIS
Analiza przestrzenna ilosci sedymentu oraz pokrywy roslinnej w zlewni rzeki Tapacura okreslona na podstawie zdalnych obserwacji oraz analizy GIS
Autorzy:: Silva, R M
Santos, C.A.G.
Gico Lima Montenegro, S.M.
Silva, L.P.
Tematy:: spatial analysis
vegetation cover
sediment yield
Tapacura River
catchment
remote sensing
GIS analysis; Pokaż więcej
Wydawca:: Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Powiązania:: https://bibliotekanauki.pl/articles/81843.pdf Link otwiera się w nowym oknie
Opis:: Mapping and assessment of erosion risk is an important tool for planning of natural resources management, allowing researchers to propose modifi cation in land-use properly and implement more sustainable management strategies in the long-term. The Tapacurá river catchment, located in Pernambuco State, Northeastern Brazil, is one of the planning units for management of water resources of Recife Metropilitan Region (RMR), and it is divided into 12 sub-basins. The objective of this study is to evaluate the spatial variability of vegetal cover and sediment yield in this basin through remote sensing and GIS techniques. Maps of the erosivity (R), erodibility (K), topographic (LS), cover-management (C) and support practice (P) factors were derived from the digital elevation model (DEM), climate database, and soil and NDVI maps, taking into account information available in the literature. In order to validate the simulation process, Sediment Delivery Ratio (SDR) was estimated. The obtained NDVI map showed vegetation loss during the analyzed period, indicating a distinct contrast between loss and gains of vegetation index. The vegetation and sediment yield mapping showed to be a useful tool for environmental monitoring and management, which can provide satisfactory results when jointly used. The results suggest a mean SDR around 0.9 and estimate the sediment yield as 23.98 ton/ha/month.
Analiza przestrzenna ilości sedymentu oraz pokrywy roślinnej w zlewni rzeki Tapacura określona na podstawie zdalnych obserwacji oraz analizy GIS. Artykuł przedstawia sposób wykorzystania zebranych w terenie danych dotyczących pokrywy roślinnej oraz ilości sedymentu określonego za pomocą zdalnych obserwacji oraz analizy GIS w celu monitorowania środowiska i zarządzania zlewniami. W pracy wykorzystano metodę USLE-SDR, a także cyfrowy model terenu. Badania prowadzono w zlewni rzeki Tapacura w północno-wschodniej Brazylii. Wyniki sugerują przyjęcie wartości parametru SDR = 0,9, a oszacowana wielkość transportu rumowiska wynosi 23,98 t/ha/miesiąc.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Research on the Portuguese building stock and its impacts on energy consumption – an average U-value approach
Autorzy:: Sousa, J.
Bragança, L.
Almeida, M.
Silva, P.
Tematy:: zasoby budynków
zasoby energii
zużycie energii
element konstrukcyjny
przenikanie ciepła
współczynnik przenikania ciepła
building stock
energy resources
energy consumption
structural element
heat transfer
heat transfer coefficient; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/231236.pdf Link otwiera się w nowym oknie
Opis:: The article aims to evaluate the Portuguese building stock energy policies and strategy for energy saving in buildings among the EU members. It was found out the average heat transfer coefficients of the main structural elements of Portuguese Buildings and analyzed the U-values of this elements considering different time periods. The fundamentals of this study were funded by the Agency for Development and Innovation (ADI) and co-financed by the European Regional Development Fund (FEDER) through the Operational Program for Competitiveness Factors (POFC) assigned to the Building Physics and Construction Technology Laboratory with the reference SB Tool SPT_2011_4.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Development of environmentally-friendly technologies based on the Double-ECO model – an evaluation platform
Autorzy:: Pena-Gonzalez, L. E.
Da Silva, P.
Tanabe, I.
Tematy:: eco-efficiency
lubrication
life cycle assessment (LCA)
Mahalanobis-Taguchi system; Pokaż więcej
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Powiązania:: https://bibliotekanauki.pl/articles/100204.pdf Link otwiera się w nowym oknie
Opis:: In recent years, the urgency to create environmentally-friendly technologies has dramatically increased. However, these technologies are usually not adopted due to their large cost and low profit. Previously the “Double-ECO model” has been proposed as a methodology that reconciles both “Economy” and “Ecology”, which relies on the exploration of technology alternatives that offer an improved mechanical performance. Here, as mechanical performance, cost and environmental impact were meant to be approached under the same degree of priority, this model was thought to offer the basis for a broader technology development framework. The current research initiates said framework by proposing an evaluation platform, which through a transition from a focus on environmental-friendliness towards an improved eco-efficiency definition lays groundwork for an automated evaluation. This was done by defining a dimensionless evaluation parameter based on existing methodologies and referred as the “DE Index”. This paper applied the proposed evaluation method into a machine tool lubrication technology example. It was concluded that, (1) the platform was able to effectively compare technologies under the proposed eco-efficiency parameter, (2) the developed technology possessed improvements in the environmental pollution output, mechanical performance and cost when compared to conventional technologies.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: A Simple Localized-Itinerant Model for PrAl$\text{}_{3}$: Crystal Field and Exchange Effects
Autorzy:: Von Ranke, P. J.
Palermo, L.
Da Silva, X. A.
Tematy:: 75.10.Dg
75.30.Cr; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1891680.pdf Link otwiera się w nowym oknie
Opis:: We present a simple magnetic model for PrAl$\text{}_{3}$. The effects of crystal field are treated using a reduced set of levels and the corresponding wave functions are extracted from the actual crystal field levels of Pr$\text{}^{+3}$ in a hexagonal symmetry. The exchange between 4f- and conduction-electrons are dealt within a molecular field approximation. An analytical magnetic state equation is derived and the magnetic behaviour discussed. The parameters of the model are estimated from a fitting of the inverse susceptibility of PrAl$\text{}_{3}$ given in the literature.
Dostawca treści:: Biblioteka Nauki

Artykuł

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Skocz do pozycji: 5.

Tytuł:: Machine tool distortion estimation due to environmental thermal fluctuations – a focus on heat transfer coefficient
Autorzy:: Da Silva, P.
Pena-Gonzalez, L. E.
Tanabe, I.
Takahashi, S.
Tematy:: environmental thermal fluctuations
thermal deformation
machine tool
heat transfer coefficient; Pokaż więcej
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Powiązania:: https://bibliotekanauki.pl/articles/99879.pdf Link otwiera się w nowym oknie
Opis:: Thermally induced errors have been approached in multiple ways due to the influence these have over the positional accuracy of a machine tool. Here, approaches regarding environmental thermal fluctuations surrounding a machine tool remain to be explored in detail. These fluctuations have been explored in terms of the heat transfer coefficient and thermal radiation of the machine shop walls, as well as in terms of seasonality and varying thermal gradients. This paper presents additional considerations regarding environmental temperature perturbations, as heat transfer coefficient fluctuations in the machine shop were thought to play a significant role in machine tool thermal deformation a broader term for these phenomena, environmental thermal fluctuations, was defined and evaluated. Specifically, an environmental thermal data survey of a machine shop was explored. This data was then applied to a NC milling machine and a CNC jig borer FEM analyses and compared to experimental data. FEM simulations were then used to demonstrate that convection regimes and heat transfer coefficient values at a machine shop have a significant influence over machining precision. Here, under maximum and minimum heat transfer coefficient values, the NC milling machine and CNC jig borer simulations results showed an error of cut difference up to 36.5 μm and 18.17 μm, respectively. In addition, as the importance of the heat transfer coefficient was highlighted, considerations regarding machine tool surface color were deemed relevant and were described.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Selectivity of diphenyl-ether herbicide with postemergence applications in chickpea
Autorzy:: Silva, L.G.B.
Da Silva Araujo, L.
Goncalves, D.J.
Souza Valente, M.
Da Silva, A.R.
Nascimento, W.M.
Ribeiro da Cunha, P.C.
Tematy:: Cicer arietinum
diphenyl-ether herbicides
weeds; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/2084719.pdf Link otwiera się w nowym oknie
Opis:: There are few reports in literature about the selectivity of postemergence application of herbicides for the control of eudicotyledon weeds (broadleaf) in chickpea. For this reason, the aim of this study was to investigate the selectivity of diphenyl-ether herbicides in chickpea influenced by the herbicides and application rates. A field experiment was conducted from February to June 2017 in Urutaí, state of Goiás, Brazil. Cultivar BRS Aleppo was used in the experiment. The experiment was set up in a randomized block design with 2 × 3 + 1 factorial arrangement and three replications. The first factor was herbicides (fomesafen and lactofen) with the second factor being herbicide rate (50, 75, and 100% of referenced rate) plus an untreated check as a comparison. The applied rates of herbicides were 250 and 180 g ⋅ ha–1 of fomesafen and lactofen, respectively. The selectivity of herbicides was evaluated according to agronomic characteristics (plant population, height, dry matter, number of pods per plant and 100-grain weight) and yields. Both herbicides, regardless of dosage, were selective in chickpea cultivation, even exhibiting leaf necrosis symptoms with visible injuries below 20% with no effect on yield.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Methodological aspects of the quantification of dispersible clay and its relationship with soil properties along a catena under no-till management
Autorzy:: de Paula, A.L.
Giarola, N.F.B.
de Lima, R.P.
Wiecheteck, L.H.
da Silva, A.P.
Tematy:: soil structure
erodibility
aggregation; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Agrofizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2082881.pdf Link otwiera się w nowym oknie
Opis:: Continuous no-till management of sloping cultivated areas can promote soil property transformations, causing changes in aggregation and dispersion. The objective of this work was (i) to quantify the readily and mechanically dispersible clays using different methods and (ii) to examine their relationships with soil properties along a catena under no-till management. For this study, the catena was divided into three distinct parts: crest, upper-slope and mid-slope positions. Undisturbed soil cores were sampled at each slope position to determine the following soil properties: organic carbon, Ca2+, Mg2+, K+, Al3+, P, pH, cation exchange capacity and total clay content. Additionally, the levels of readily dispersible clay were measured using turbidimeter and hydrometer methods, whereas mechanically dispersible clay was quantified using the turbidimeter method. We observed high influence of total clay content and organic carbon on soil flocculation; P, Mg2+ and cation exchange capacity were positively related to clay dispersion. Soil management and water transport downslope are probably influencing changes in soil properties and determining the distribution of dispersible clay contents along the catena. No relationships were observed between readily dispersible clay measured using turbidimeter and hydrometer in terms of quantity. Hydrometer and turbidimeter measurements can deliver significantly different results regarding dispersible clay quantification, potentially leading to misinterpretations concerning the amount of clay dispersed in water.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Ultra-low-voltage LNA with high gain and low noise figure
Autorzy:: Bastos, I.
Oliveira, L. B.
Oliveira, J. P.
Goes, J.
Silva, M. M.
Tematy:: LNA
CMOS
noise cancellation
redukcja szumów; Pokaż więcej
Wydawca:: Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Powiązania:: https://bibliotekanauki.pl/articles/397785.pdf Link otwiera się w nowym oknie
Opis:: We present a balun LNA with noise and distortion cancellation using double feedforward. A common-gate and a common-source stage are combined, and their resistive loads are replaced by transistors biased close to saturation to allows low supply voltage, without gain degradation. The proposed feedforward boosts the LNA gain and reduces the noise ﬁgure (NF). Simulation results with a 130 nm CMOS technology show that the gain is up to 24 dB and the NF is below 3.2 dB. The total power dissipation is 2.25 mW, leading to an FoM of 6.4 mW-1 with 0.6 V supply.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Calculation of grounding grids parameter at arbitrary geometry
Autorzy:: Silva, C. L. B.
Pires, T. G.
Calixto, W. P.
Oliveira, D. N.
Souza, L. A. P.
Filho, A. M. S.
Tematy:: grounding grids parameters
Heppe
soil stratified in two layers; Pokaż więcej
Wydawca:: EEEIC International Barbara Leonowicz Szabłowska
Powiązania:: https://bibliotekanauki.pl/articles/136173.pdf Link otwiera się w nowym oknie
Opis:: This paper deals with the computation of ground resistance, surface voltage, touch voltage and step voltage, to mesh with horizontal wires arranged in different angles. The computer program implemented used in the mathematical modeling is based on the method proposed by Heppe, which allows obtaining the grounding parameters for homogeneous soil and soil stratified in two layers. The results obtained with the proposed method will be compared with other methods in literature. Also will be presented the results of a grounding grid using wires at various angles.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Sensorless Control of Surface Mounted Permanent Magnet Synchronous Motors Using Matrix Converters
Autorzy:: Saltiveri, D.
Arias, A.
Asher, G.
Sumner, M.
Wheeler, P.
Empringham, L.
Silva, C.
Tematy:: sensorless control
permanent magnet synchronous motor
matrix converters; Pokaż więcej
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Powiązania:: https://bibliotekanauki.pl/articles/262580.pdf Link otwiera się w nowym oknie
Opis:: This paper investigates the influence of the power converter on the performance of Surface Mounted Permanent Magnet Synchronous Motor drives, which employ High Frequency voltage injection to achieve low and zero speed control. Experimental results demonstrate the remarkable performance of the sensor less speed and position control employing the Matrix Converter and the contributions of the Space Modulation Profiling technique. The Matrix Converter has almost zero dead time, which means that behaves almost like an ideal power converter and achieves better results than the conventional Voltage Source Inverter. A comparison of the sensor less technique proposed using both converters is made.
Dostawca treści:: Biblioteka Nauki

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