Search results for "Measurement"
showing 10 items of 2918 documents
Canopy Architecture Appraisal by Fractal Dimension of 'Flordastar' Peach Trees Grafted onto Different Rootstocks
2007
The objective of this research was to evaluate the modification of canopy architecture of ''Flordastar'' peach (Prunus persica L. Batsch) grafted onto rootstocks with different vigour, by the use of fractal dimension (D). The hypothesis was that different vigour rootstocks are able to modify the complexity of the branching pattern and that this effect can be assessed by a geometric parameter such as the fractal dimension (D) of the 2D projection of tree branching structure. The observations were carried out in a four-year-old experimental orchard of cv. ''Flordastar'' peach trees grafted onto Ishtara, Barrier, GF677 and MrS 2/5 rootstocks. On digital pictures of leafless, dormant peach tree…
Representation theory treatment of measurement semantics for ratio, ordinal and nominal scales
1997
Within the scope of the representational theory a formal framework for description of semantic aspects of measurement on different scales is proposed. This is done by means of a first-order formal logical system consisting of a set of empirical predicates which play the part of a data structure in the framework, a set of operations by means of which syntactically correct statements can be formed; a set of axioms being true statements and a set of numerical statements which is an aggregation of potential measurement results carrying a meaningful load. On this basis the notation of semantic information on various scales is introduced and some common claims about the measurement semantic infor…
Quantum Field Theory
2018
Quantum field theory (QFT) shares many of its philosophical problems with quantum mechanics. This applies in particular to the quantum measurement process and the connected interpretive problems, to which QFT contributes hardly any new aspects, let alone solutions. The question as to how the objects described by the theory are spatially embedded was already also discussed for quantum mechanics. However, the new mathematical structure of QFT promises new answers, which renders the spatiotemporal interpretation of QFT the pivotal question. In this chapter, we sketch the mathematical characteristics of QFT and show that a particle as well as a field interpretation breaks down.
Impact of transparent conductive oxide on the admittance of thin film solar cells
2010
Abstract The impact of transparent electrically conducting oxide (TCO) on the admittance measurements of thin film p–i–n a-Si:H solar cells was investigated. Admittance measurements on solar cell devices, with different area and geometry, in a wide range of frequencies and biases were performed. The admittance measurements of the investigated solar cells, which use the TCO as an electrical contact, showed that the high frequency admittance per area unit depends on the area. This effect increases both with the probe frequency and the size of the solar cells. Transmission line model valid for strip geometry which explains how the resistivity of the TCO layer impacts the measured admittance of…
Dependence of thermal conductivity on structural parameters in porous samples
2012
The in-plane thermal conductivity of porous sintered bronze plates was studied both experimentally and numerically. We developed and validated an experimental setup, where the sample was placed in vacuum and heated while its time-dependent temperature field was measured with an infrared camera. The porosity and detailed three-dimensional structure of the samples were determined by X-ray microtomography. Lattice-Boltzmann simulations of thermal conductivity in the tomographic reconstructions of the samples were used to correct the contact area between bronze particles as determined by image analysis from the tomographic reconstructions. Small openings in the apparent contacts could not be de…
Numerical study of the accuracy of temperature measurement by thermocouples in small-scale reactors
2018
Proper temperature measurement is imperative in any laboratory study if reliable data are to be obtained, particularly in the field of chemical kinetics. In this paper we analyze in silico some typical thermowell configurations used in small-scale reactors by coupling computational fluid dynamics (CFD) with conjugated heat transfer phenomena. This allows us to identify deviations in measurements arising from thermal radiation and self-conductivity in mid and high temperature ranges, in addition to radial temperature gradients. A novel design is proposed and optimized by additional simulation, showing potential for faster and more accurate temperature measurements.
Batch experiments for the determination of the Ti(IV,III) couple in 1 moldm-3 HCl, 2 moldm-3 NaCl medium at 25°C
2009
The determination of the Ti(IV, III) redox couple formal potential in 1 M HCl 2 M NaCl medium at 25°C through batch experiments involving the preparation of Ti(IV) and Ti(III) mixtures via the reaction of Ti(IV) with Zinc amalgam, has been carried out with emf measurements in order to verify the correctness of the previous value that the authors obtained by a coulometric-potentiometric investigation in the same conditions. The results from the two independent methods are in good agreement: 9 ± 1 mV the first and 9 ± 2 the average batch result.
Regularization Method in Infrared Image Processing
2003
Abstract Infrared images often present distortions induced by the measurement system. Thus, image processing is a vital part of infrared measurements. A distortion model based on a convolution product is presented. Image restoration is an ill-posed problem and its solution can be obtained using regularization methods. In this paper, image restoration is performed using a variation of Tikhonov regularization that makes use of the particular form of the convolution kernel matrix, which is built as a block-circulant matrix that admits a diagonal form in the two-dimensional Fourier space. The restoration procedure is used to restore a knife-edge infrared source image.
High Resolution Time Domain Reflectometry for Dielectric State Monitoring in High Voltage Cables
2017
A high resolution Time Domain Reflectometry system has been designed in order to investigate the possibility of measuring with good accuracy the dielectric properties of high voltage cables insulator materials by means of Time-of-Flight measures. The system employs a dedicated Time-To-Digital Converter in order to achieve a time resolution of 90 ps. By exploiting averaging techniques the resolution has been further increased. Experimental results showed the possibility of measuring the dielectric constant with a resolution of 0.03%.
Effects of hydrazyl group containing drugs on leucocyte functions: an immunoregulatory model for the hydralazine-induced lupus-like syndrome.
1985
Isoniazid (INH) and hydralazine (HYD) are transglutaminase (TGase, E.C.2.3.2.13.) substrates containing catalytically recruitable hydrazyl groups. Since they can be expected to inhibit TGase-mediated cell functions by competing with physiological substrates, their effect upon allogeneically and lectin-induced proliferation of mononucleocytes and upon zymosan-induced chemiluminescence of phagocytes was studied. Both compounds inhibited chemiluminescence in a dose-dependent manner. ID50 of HYD was consistently below 20 microM, while that of INH was above 120 microM. Proliferation of immunocompetent cells was suppressed by HYD with an ID50 of 60 microM, INH was inhibitory only above 5000 micro…