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The biomass assessment handbook : energy for a sustainble evironment
\"The increasing importance of biomass as a renewable energy source has led to an acute need for reliable and detailed information on its assessment, consumption and supply. Responding to this need, and overcoming the lack of standardised measurement and accounting procedures, this best-selling handbook provides the reader with the skills to understand the biomass resource base, the tools to assess the resource, and explores the pros and cons of exploitation. This new edition has been fully updated and revised with new chapters on sustainability methodologies. Topics covered include assessment methods for woody and herbaceous biomass, biomass supply and consumption, remote sensing techniques, food security, sustainability and certification as well as vital policy issues. The book includes international case studies on techniques from measuring tree volume to transporting biomass, which help to illustrate step-by-step methods. Technical appendices offer a glossary of terms, energy units and other valuable resource data. \"-- Provided by publisher.
Book
Quantum fluctuation theorems and power measurements
Work in the paradigm of the quantum fluctuation theorems of Crooks and Jarzynski is determined by projective measurements of energy at the beginning and end of the force protocol. In analogy to classical systems, we consider an alternative definition of work given by the integral of the supplied power determined by integrating up the results of repeated measurements of the instantaneous power during the force protocol. We observe that such a definition of work, in spite of taking account of the process dependence, has different possible values and statistics from the work determined by the conventional two energy measurement approach (TEMA). In the limit of many projective measurements of power, the system's dynamics is frozen in the power measurement basis due to the quantum Zeno effect leading to statistics only trivially dependent on the force protocol. In general the Jarzynski relation is not satisfied except for the case when the instantaneous power operator commutes with the total Hamiltonian at all times. We also consider properties of the joint statistics of power-based definition of work and TEMA work in protocols where both values are determined. This allows us to quantify their correlations. Relaxing the projective measurement condition, weak continuous measurements of power are considered within the stochastic master equation formalism. Even in this scenario the power-based work statistics is in general not able to reproduce qualitative features of the TEMA work statistics.
Journal Article
Calorimetric method for measuring high ultrasonic power using water as a heating material
The present study shows the calorimetric method for measuring high ultrasonic power using water as the heating material. In recent years, at the National Metrology Institute of Japan (NMIJ), an ultrasonic power primary standard of from 1 mW to 15 W has been established by the radiation force balance (RFB) method. Conventionally, the RFB method is widely used for ultrasonic power measurement, but this method is not suitable for very high power measurement due to thermal damages to the absorbing targets. High power ultrasonic standards, however, are being required by medical HITU measurements and in the sonochemistry industry. In order to meet these requirements, we have started to develop an ultrasonic power standard between 15 W and 200 W. Our final goal is an ultrasonic power standard of up to 500 W. The calorimetric method is an alternative ultrasonic power measurement method to the RFB method. We have adopted this method and use water as the heating material. Water has excellent features as a standard material, because the physical properties of water are well known. In the present study, we present an experimental system and the results for an ultrasonic power standard of up to 100 W. The measured ultrasonic power agreed well with the NMIJ primary standard up to 25 W.
Journal Article
Detecting clear‐sky periods from photovoltaic power measurements
A method for detecting clear‐sky periods from photovoltaic (PV) power measurements is presented and validated. It uses five tests dealing with parameters characterizing the connections between the measured PV power and the corresponding clear‐sky power. To estimate clear‐sky PV power, a PV model has been designed using as inputs downwelling shortwave irradiance and its direct and diffuse components received at ground level under clear‐sky conditions as well as reflectivity of the Earth's surface and extraterrestrial irradiance, altogether provided by the McClear service. In addition to McClear products, the PV model requires wind speed and temperature as inputs taken from ECMWF twentieth century reanalysis ERA5 products. The performance of the proposed method has been assessed and validated by visual inspection and compared to two well‐known algorithms identifying clear‐sky periods with broadband global and diffuse irradiance measurements on a horizontal surface. The assessment was carried out at two stations located in Finland offering collocated 1‐min PV power and broadband irradiance measurements. Overall, total agreement ranges between 84% and 97% (depending on the season) in discriminating clear‐sky and cloudy periods with respect to the two well‐known algorithms serving as reference. The disagreement fluctuating between 6% and 15%, depending on the season, primarily occurs while the PV module temperature is adequately high and/or when the sun is close to the horizon with many more interactions between the radiation, the atmosphere and the ground surface. With the exponential growth of PV installations and expansion of PV networks to respond to the increasing demand of electricity production, PV power measurements have become more and more spatiotemporally available all over the world and could serve as a useful proxy for detecting clear‐sky periods. This paper proposes a clear‐sky detection method using PV power measurements. The method performs very well when compared to two well‐known methodologies using broadband global and diffuse irradiance measurements on a horizontal surface.
Journal Article
Reactor power measurement using N16 and N17 production rate in MARIA reactor
In the water surrounding the reactor core, especially in the water flowing through the cooling system of the fuel channels, the (n,p) reactions on 16 O and 17 O occur producing 16 N and 17 N isotopes. The decay products of 16 N and 17 N may be used to regain information about the reactor power and the neutron flux density in the core. The aim of the study was the simulation of the activity of the 16 N and 17 N isotopes during the water flow through the fuel channels’ cooling system in the MARIA reactor, checking the possibility of the improvement of the currently performed measurements and the determination of the most optimal placement for the activity measurements. The simulations were performed taking into account the power generated by the individual fuel rods and the information on their burnout. The calculations were made for various configurations of the reactor core over the last 3 years. To check the reliability of the simulation, the activation measurement of the high-purity Au foil was performed. The Au have been activated at the outlet pipeline of the cooling system during whole reactor cycle (4 days) and after that, the activity of the produced 198 Au was measured. The 198 Au is the product of the (n, gamma) reaction on the 197 Au and its activity can be the measure of the neutron flux density in the foil, which in turn gives the information of the 17 N content in the cooling water. For better neutron flux density estimations, the models of the fuel element and the model of the outlet pipe with the Au foil were made in the MCNP simulation code. The Au foil activation was also simulated in the Fispact-II code system which allowed estimating the neutron flux density needed to obtain the measured foil activity. This work shows the results of the studies together with the possible sources of uncertainties and the estimation of their influence on the final result.
Journal Article
Corneal power measurements by ray tracing in eyes after small incision lenticule extraction for myopia with a combined Scheimpflug Camera–Placido disk topographer
PurposeTo evaluate the accuracy of the measurements of corneal power obtained by ray tracing with a combined Scheimpflug camera–Placido disk corneal topographer (Sirius) in eyes after small incision lenticule extraction for myopia (SMILE).MethodsRetrospective cases study includes 50 eyes of 50 patients who underwent myopic SMILE. Mean value of simulated keratometry (Kpost), mean pupil power (MPP) (ray tracing, diameter of the entrance pupil range 3–6 mm), anterior and posterior corneal radius, and corneal thickness were obtained with Sirius topographer preoperatively and three months postoperatively, as well as cycloplegic refraction. True net power, equivalent keratometry readings, and Haigis equivalent power formula were calculated, and these measurements, MPP and Kpost, were compared with the corneal power calculated with the clinical history method (CHM).ResultsCorneal power measurements obtained with all methods were significantly different from CHM (P < 0.001), except the value of MPP obtained at 5.5 mm (P = 0.927). A good direct correlation was found between CHM and all measurements. The distribution of differences as compared with the CHM showed that the lowest difference corresponded to the value of MMP at 5.5 mm (− 0.002 ± 0.6). The Bland–Altman plots for the MPP at 5.5 mm showed 95% limits of agreement between − 1.1787 D and 1.1741 D.ConclusionsMPP obtained by ray tracing within a diameter of entrance pupil of 5.5 mm could predict corrected corneal power derived from the CHM in eyes following SMILE surgery.
Journal Article
Developing RF Power Sensor Calibration Station in Direct Comparison Transfer System using Vector Network Analyzer
Calibration of RF power sensors is crucial issue in RF power measurements. Many calibration laboratories use the direct comparison transfer system with a signal generator and a power splitter. Increasing performance of modern vector network analyzers makes it possible to perform a power sensor calibration with acceptable uncertainties. The main advantage when using a VNA is a simple measurement setup with a wide frequency range (up to 50 GHz, limited only by the VNA and the standard power sensor), where all of required components, i.e. signal generator, a directional coupler and a reference power indicator are built in the VNA technology. This paper r+eports performing a VNA-based RF power sensors calibration for 10 MHz - 18 GHz band, carried out in the Laboratory of Electric, Electronic and Optoelectronic Metrology at the National Institute of Telecommunications in Warsaw, Poland. In order to validate the proposed solution two of power sensors were calibrated at a reference laboratory. The validation consisted of two steps. At first, one of those characterized power sensors was calibrated at our laboratory in direct comparison transfer system. Finally, the results obtained from the VNA-based system were compared with the previously obtained ones.
Journal Article
A Raspberry Pi Cluster Instrumented for Fine-Grained Power Measurement
Power consumption has become an increasingly important metric when building large supercomputing clusters. One way to reduce power usage in large clusters is to use low-power embedded processors rather than the more typical high-end server CPUs (central processing units). We investigate various power-related metrics for seventeen different embedded ARM development boards in order to judge the appropriateness of using them in a computing cluster. We then build a custom cluster out of Raspberry Pi boards, which is specially designed for per-node detailed power measurement. In addition to serving as an embedded cluster testbed, our cluster’s power measurement, visualization and thermal features make it an excellent low-cost platform for education and experimentation.
Journal Article
Measurement of 40 power system harmonics in real-time on an economical ARM® Cortex™-M3 platform
Within future homes and electrical power networks, emphasis is being placed on intelligent, distributed measurement devices. In particular, the recognition of individual or aggregated loads through harmonic signature has been proposed as a useful way to enhance the value of home energy monitoring/control. Clearly, the cost of implementing such measurement devices is a major barrier to acceptance. In a recent project, a challenge was set to implement real-time software on an ARM® Cortex™ LPC1768 microcontroller platform (chip cost c. £4). The software must be capable of measuring a single-phase AC frequency, real and reactive power flows and provide a full breakdown of the voltage and current (and power) behaviour via harmonic analysis from DC to the 40th, in real-time with a new output every 20 ms. In addition, the algorithm must be capable of adapting the measurement when the frequency is not nominal (50 Hz) so that spectral leakage is minimised. It is found that the LPC1768 processor is capable of supporting such an algorithm when it is coded appropriately. This knowledge de-risks the proposed use of such cheap microcontrollers for these relatively complex tasks.
Journal Article
Engineering practice of confirming activity based on Commercial Grade item
This paper reviews the current status of CGD activities in nuclear power measurement and control projects in recent years, including bidding, process, method, and project implementation. This paper focuses on analyzing of some problems found in practice, which fully reflects the significance and necessity of CGD, and gives suggestions, hoping that the industry can speed up to establish the relevant domestic standard system and strengthen the supervision and implementation of engineering projects.
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