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Convolution and Superposition Methods
Published in Jerry J. Battista, Introduction to Megavoltage X-Ray Dose Computation Algorithms, 2019
For example, as shown in Figure 4.21, the energy released from voxel A should deposit energy to both voxels B and B′, but in the collapsed cone approximation, the energy that should have been deposited to voxel B′, is deposited onto voxel B instead. For a homogeneous medium and similar primary energy fluence at nearby voxels A and A′, we can see that the missing energy to B′ from A will be compensated by extra energy received from A′. It is important to note that energy conservation is strictly preserved in this approximation. For strongly inhomogeneous medium, this approximation may introduce some errors. For general clinical practice with typical tissue distributions, this approximation turns out to be generally acceptable, and the method is more accurate than 2D convolution methods, especially in the presence of inhomogeneities(Fogliata et al. 2007).
Radioactivity and Matter
Published in Ivan G. Draganić, Zorica D. Draganić, Jean-Pierre Adloff, Radiation and Radioactivity on Earth and Beyond, 2020
Ivan G. Draganić, Zorica D. Draganić, Jean-Pierre Adloff
Recognition of the weak force arose from studies of β-radioactivity. Two apparently strange things happen in the β-decay. First, the energy of the emitted electron is not constant but varies from zero to a maximum value. Further, the negatively charged electron escapes from the positive nucleus without being apparently affected by the presence of the electromagnetic and strong nuclear forces. The explanation is that, together with the electron, the nucleus emits an accompanying uncharged particle with a vanishingly small mass, the neutrino, which carries the seemingly missing energy of the radioactive decay.
Electronics Requirements for Collider Physics Experiments
Published in John D. Cressler, H. Alan Mantooth, Extreme Environment Electronics, 2017
Most but not all detectors for collider experiments are designed to capture as much of the complete solid angle surrounding the interaction point as possible. This is important in order to detect all the particles produced in the scattering and thereby reconstruct the scattering event. Furthermore, some particles likely to be produced in these interactions, namely, the neutrino particle, do not readily interact with matter and require tons of material to detect, much more material than is feasible for a general-purpose collider detector. Therefore, these particles are not recorded by the collider detector system. Instead, missing energy in the event is attributed to neutrinos, making the full coverage, typically referred to as hermeticity, essential so as not to lose any detectable particles and attribute that loss to an undetectable neutrino. The ATLAS detector built for experiments at the Large Hadron Collider (LHC) at the CERN laboratory in Geneva, Switzerland is a good example of such a detector [3]. A cutaway drawing of this detector is shown in Figure 77.1. The full detector is made up of many sub-detectors, each of which surrounds the interaction point and serves to detect a certain type of particle. The innermost three sub-detectors, the pixel detector, the semiconductor tracker (SCT), and the transition radiation tracker (TRT), detect charged particles and reside inside of a 2T solenoidal magnetic field to allow determination of the particles’ momenta by measurement of the radius of curvature of their trajectories. Next, the liquid argon electromagnetic calorimeters(LAr) measure the energy of electrons, positrons, and gammas. The Tile calorimeters measure the energy of hadrons (protons, neutrons, pions, etc.) and finally the muon chambers measure muons, which emerge from the calorimeters and are again bent by a set of toroidal magnets. The enormous size of the detector (See the small 6 ft tall persons in Figure 77.1 for scale.) is required in order to capture all the energy from the reactions and to provide sufficient travel distance through the magnetic fields to measure the momenta of the very high-energy particles.
Heritage-BIM for energy simulation: a data exchange method for improved interoperability
Published in Building Research & Information, 2023
Kristis Alexandrou, Stavroula Thravalou, Georgios Artopoulos
Following the initial import of the gbXML model, at this stage the missing energy data are imported to the model using supplementary exchange process. As previously mentioned, Design Builder enables additional data exchange through the model data grid view window. The grid contains multiple layouts of building information in the form of traditional spreadsheet, with each containing particular attributes already registered to the mode, namely, HVAC, internal gains, lighting, materials, mechanical ventilation, natural ventilation and setpoints. Each spreadsheet was sorted ascendingly according to space number. All layouts, excluding the materials one, were exported to CSV files. These files contained information imported form the initial gbXML exchange process, yet, containing missing or incorrect data, most of which were affected by faulty replacements from Design Builder’s default template values. The exported CSV files have been accessed and analysed by the visual programming tool embedded in Revit, Dynamo. The retrieved data were further restructured to have the same order with the respective ones located in the BIM model families, i.e. spaces and zones. By extent, in case of inconsistencies, data types have been converted, i.e. Boolean toggle in the form of number (0/1) to text (true/false). The retrieved true values collected from the BIM model were used to replace the relevant CSV, and stored in separate, updated files (Figure 7). A sample code block responsible for replacing incorrect heating and cooling setpoint data of the exported ‘setpoints’ CSV file is presented in Figure 8.
Implementation of a power supervisory for hybrid power system
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Rim Ben Ali, Souha Bousselmi, Salwa Bouadila, Müslüm Arıcı, Abdelkader Mami
Figure 14 presents the variation of the wind speed during three windless days in December from 01/12/2018 to 03/12/2018. The simulation results showed that during the third day (03/12) the generated power and also the SOC state reached their maximum value when the wind velocity reaches 15 m/s (Figure 15). But, during a low wind speed, the required power is not fully achieved. In this case, the power generated from the WTS will be totally distributed to the load and the missing energy will be delivered by the battery until reaching its SOCmin as shown in Figure 16.
Evaluation of some effective parameters on the energy efficiency of on-board photovoltaic array on an unmanned surface vehicle
Published in Ships and Offshore Structures, 2019
Ashkan Makhsoos, Hossein Mousazadeh, Seyed Saeid Mohtasebi
Loss diagram is sketched for a typical year by considering an everyday consumer which needs 6.8 kWh/day. Despite the fact that routine hydrography in the port is needed once in a month and it may take just two days but everyday consumption is assumed. Although the uncommon assumption caused about 16% of missing energy in diagram, array can provide all the required energy in real. This amount of energy can be maximised by controlling losses. Reasons for elimination of energy production is shown in Figure 6. According to the loss diagram, temperature is the most important controllable parameter.