Independent Calculations Research Articles

Theoretical attempt to predict the cross sections in the case of new superheavy elements

For the first time, within the framework of the dynamical cluster-decay model (DCM) by Gupta and collaborators, we provide reasonable estimations for cross sections of nuclear systems which will give rise to new superheavy elements. The important point and the new approach presented in this contribution are the theoretical calculations done without tracking any reference to experimental data; i.e., these are independent calculations. We will provide a method for reasonable estimates for the cross sections of unobserved possible decay channels in a nuclear reaction. We will demonstrate the capability of the DCM to give a probable/sensible range of the cross section. This exercise of theoretical calculations within the DCM may benefit experiments for the discovery of new superheavy elements. Our results can provide hints to the experimentalist to choose proper incoming channels in order to perform experiments. We have applied this new strategy to calculate the cross sections of the already studied compound nuclei $Z=116$ and 118 via hot fusion reactions, and observed that our calculated range of cross sections has given values within the reach of experimental studies. Both compound nuclei were studied earlier by one of the authors for the angle $\mathrm{\ensuremath{\Phi}}={0}^{\ensuremath{\circ}}$, including quadrupole deformations, ${\ensuremath{\beta}}_{2i}$ alone with ``optimum'' orientations (${\ensuremath{\theta}}_{\mathrm{opt}.}$). Here, we consider the same specifications in order to study the new approach using the DCM. The principal aim of this work is to study the capability of the DCM to determine the cross sections for new elements, where experimental data are not available.

Verification of monitoring unit calculations for the 3D conformal radiotherapy treatment planning system

The present work aims to validate an Independent Calculation of Monitoring Units (ICMU) software developed to accurately calculate the number of Monitoring Units (MU) used in radiation treatment. The calculation was performed for the photon beam with a variety of nominal energies (6 MV − 18 MV) and filed size ranging from 3 × 3 cm2 to 40 × 40 cm2. Two set-up conventions of treatment techniques were tested, a constant source to surface distance (SSD) and an isocentric set-up with a constant source to axis distance (SAD). The ICMU software was written in C-sharp (C #), using the equivalent square field size concept to calculate the radiation field quantities and connects to a database containing measurements quantities such as Tissue Phantom ratio (TPR) and Output Factors (OFs). The ICMU was successfully validated by comparing it to the Treatment Planning System (TPS) or CMS Monitor Unit Calculations (CMS_MU). The required standards were satisfactorily met (5.0%).

Applicability of two-dimensional numerical simulation associated with vortex-induced vibration response of the circular cylinder

ABSTRACT The VIV responses of the circular cylinder at low and moderate Reynolds numbers are calculated according to two-dimensional numerical simulation and the fourth-order Runge–Kutta algorithm. The first part of the study is focused on the applicability of 2D numerical simulation between the response of 2D numerical simulation and the actual response, which can guide the preliminary engineering studies by vortex shedding. The reasonable vortex shedding mode of each branch, and the change process of the trajectory from the ‘8’ type to the ‘droplet’ type, are discussed in the second part of the study. And independent calculations under different speed reduction conditions are employed to suit practical application scenarios. The comparison shows the applicability of the 2D numerical simulations at low Reynolds numbers. Although the amplitude calculation results at moderate Reynolds numbers are inconsistent with the experimental results, the two-dimensional numerical simulation has good reliability in the trailing vortex capture.

Monte Carlo modeling of the Elekta Versa HD and patient dose calculation with EGSnrc/BEAMnrc.

IntroductionNumerous studies have proven the Monte Carlo method to be an accurate means of dose calculation. Although there are several commercial Monte Carlo treatment planning systems (TPSs), some clinics may not have access to these resources. We present a method for routine, independent patient dose calculations from treatment plans generated in a commercial TPS with our own Monte Carlo model using free, open‐source software.Materials and methodsA model of the Elekta Versa HD linear accelerator was developed using the EGSnrc codes. A MATLAB script was created to take clinical patient plans and convert the DICOM RTP files into a format usable by EGSnrc. Ten patients’ treatment plans were exported from the Monaco TPS to be recalculated using EGSnrc. Treatment simulations were done in BEAMnrc, and doses were calculated using Source 21 in DOSXYZnrc. Results were compared to patient plans calculated in the Monaco TPS and evaluated in Verisoft with a gamma criterion of 3%/2 mm.ResultsOur Monte Carlo model was validated within 1%/1‐mm accuracy of measured percent depth doses and profiles. Gamma passing rates ranged from 82.1% to 99.8%, with 7 out of 10 plans having a gamma pass rate over 95%. Lung and prostate patients showed the best agreement with doses calculated in Monaco. All statistical uncertainties in DOSXYZnrc were less than 3.0%.ConclusionA Monte Carlo model for routine patient dose calculation was successfully developed and tested. This model allows users to directly recalculate DICOM RP files containing patients’ plans that have been exported from a commercial TPS.

Visual Memory Neural Network for Artistic Graphic Design

Artistic graphic design is the aesthetic result of the designer’s fusion of various elements, with a high degree of independence. Considering the lack of significant visual design scope and aesthetic indicators of graphic design, our research aims to build an upgraded network model that can categorize different types of artistic graphics with labels and realize the free combination of graphic solutions. We realize the scheme reorganization of artistic graphic design from the perspective of computer vision and propose the artistic graphic design method based on memory neural network. We built a computer vision environment and reconstructed the computer vision network to set up an independent deep camera vision range calculation law. Considering the artistic graphic region segmentation problem, we propose the self-attentive mechanism, which can quantitatively segment different artistic graphic regions according to temporal features, before arranging them in a sequence to obtain the graphic region feature vector. We also add the LSTM structure based on the attention mechanism to match with the self-attention features of the graphical region segmentation module and pass the matched attention feature vector to the LSTM network to extract the labeled text feature information of the graphs. To test the effectiveness of our method, we build a database of artistic graphics and set up an adaptive training process. We also compared deep learning methods of the same type, and the experimental results proved that our method outperformed other deep methods in artistic graphic design by keeping the scheme reorganization accuracy and quantitative evaluation of artistic models above 90%.

Calculation of atomic integrals between relativistic functions by means of algebraic methods

We propose the use of Sturmian basis set for relativistic atomic structure calculations. We describe a numerically stable algebraic calculation of one- and two-particle radial integrals. The method is illustrated on the basis set independent calculation of energies, electric dipole moments, hyperfine integrals and parity non-conserving (PNC) amplitude for Cs in Dirac-Hartree-Fock approximation with frozen core orbitals. The previously reported results for electric dipole moments and PNC amplitude are found to be strongly basis dependent. Program summaryProgram title: PASCCPC Library link to program files:https://doi.org/10.17632/xycmhhcr5h.1Licensing provisions: MITProgramming language: Fortran 2008Nature of problem: Precise atomic measurements require reliable and highly accurate atomic structure calculations. Here we deal with the problem of numerical stability of the atomic integrals and basis set independence of the calculations.Solution method: The radial parts of the electronic orbitals are expanded in a discrete Sturmian functions that are eigenfunctions of one of the generators of the so(2,1) Lie algebra. This algebraic structure is used to deduce algebraic relations between the radial parts of the atomic integrals. This leads to numerically stable calculation, which in turn allows to achieve basis set independence.Additional comments including restrictions and unusual features: The method is currently restricted to the Dirac-Hartree-Fock method. However, this limitation will be lifted in future versions, which will be extended with the coupled clusters method.

METODOLOGÍA PARA DEFINIR ESQUEMAS DE IRRADIACIÓN A PARTIR DE ARCHIVOS DE ESPACIOS DE FASE PARA SIMULAR PLANIFICACIÓN EN RADIOTERAPIA

The complex planning processes in radiotherapy treatments are commonly approached using computer tools that determine the dose distribution corresponding to different irradiation schemes aimed at providing viable options to fulfill the clinical and physical requirements of each case. This paper reports on a novel methodology developed to calculate spatial distributions of doses corresponding to stereotactic irradiations, incorporating arc-irradiation schemes and being representative of treatment planning, by means of phase-Spacefiles; and using Monte Carlo simulations to perform radiation transport. The methodology was implemented with the FLUKA code and was applied to a situation of clinical complexity using tomographic images of a standardized dosimetry control phantom for stereotactic radiosurgery. The preliminary results obtained from the first step of the process, aimed at incorporating simple schemes, along with clinical radiosurgery phantom irradiation, confirm the feasibility of the proposed methodology and indicate a promising performance for an alternative or independent calculation of spatial dose distributions in stereotactic irradiations.

Relativistic fine structure of the [formula omitted] ion [formula omitted]-levels

Motivated by the recent experimental measures of the 2p-states fine splitting of the muonic He4 ion (Krauth et al., 2021), we think it may be of interest to present an independent calculation in terms of the two-body relativistic equation for a scalar and a fermion developed in Giachetti and Sorace (2021, 2019) for mesic atoms. This work can thus be considered an addendum to these last papers in a different range for the masses of the two components. It gives theoretical results in good agreement with the recent experimental measures.

Implementation and application of PyNE sub-voxel R2S for shutdown dose rate analysis

PyNE R2S is a mesh-based R2S implementation with the capability of performing shutdown dose rate (SDR) analysis directly on CAD geometry with Cartesian or tetrahedral meshes. It supports advanced variance reduction for fusion energy systems. However, the assumption of homogenized materials of PyNE R2S with a Cartesian mesh throughout a mesh voxel introduces an approximation in the case where a voxel covers multiple non-void cells. This work implements a sub-voxel method to add fidelity to PyNE R2S with a Cartesian mesh during the process of activation and photon source sampling by performing independent inventory calculations for each cell within a mesh voxel and using the results of those independent calculations to sample the photon source more precisely. PyNE sub-voxel R2S has been verified with the Frascati Neutron Generator (FNG)-ITER and ITER computational shutdown dose rate benchmark problems. The results for sub-voxel R2S show satisfactory agreement with the experimental values or reference results. PyNE sub-voxel R2S has been applied to the shutdown dose rate calculation of the Chinese Fusion Engineering Testing Reactor (CFETR). In conclusion, sub-voxel R2S is a reliable tool for SDR calculation and obtains more accurate results with the same voxel size than voxel R2S.

Cosmological mass of the photon and dark energy as its Bose–Einstein condensate in de Sitter space

I develop a physical picture of dark energy (DE) based on fundamental principles and constants of quantum mechanics (QM) and general relativity (GR) theories. It derives from a conjecture of nonzero masses for nearly standard-model photons or gluons, based on QM localization at a cosmological scale. Dark energy is associated with de Sitter space and that has a fundamentally invariant event horizon, which provides the basis for my DE model. I conceive of DE as a Bose–Einstein condensate (BEC) of cosmologically massive photons, and I estimate fundamentally the binding energy per particle originating from an effectively attractive QM potential in that BEC. Since massive photons may stand at rest in a de Sitter universe with flat spatial geometry, I solve the time-independent Schrödinger equation for a nonrelativistic attractive spherical-well potential self-confining at the de Sitter horizon. The minimal critical potential depth that binds a particle state at the top of that well, combined with the prototypical condition of dark energy-pressure relation in the standard flat Lambda -CDM model, provides an estimate of the photon mass, m_g. That is supported by an independent calculation of the vacuum energy of the BEC in a de Sitter static metric with coordinate-time slicing. I also consider classical gravitational collapse for a uniform dark energy density, approaching Schwarzschild condition. These QM and GR estimates provide compatible accounts of dark energy condensation, bridging a chasm between nuclear and cosmological scales. I then investigate statistical properties of equilibrium between the g-BEC phase and the ordinary ‘vapor’ phase of m_g photons. Resulting corrections to the Planck spectrum of the CMB are too small to be detectable, at least currently. Most notably, I consider a system of cosmological units, or ‘g-units,’ that complements the fundamental system of Planck units in various ways. The geometric mean of Planck and g-mass turns out to be remarkably close to current estimates of neutrino masses, suggesting that even masses of the lightest known fermions may be deeply related to both GR and QM fundamental constants Lambda , G, c and h.

ANALISIS PENGUJIAN TAN DELTA PADA TRANSFORMATOR ARUS DI GITET TASIKMALAYA BAY PENGHANTAR BANDUNG SELATAN-1

Current transformers are essential for substation protection. It converts large currents into smaller currents that are used for measurement and triggering protection systems. Errors in the conversion of electric current can lead to measurement inaccuracies and protection system failures. Improper maintenance and use can shorten the life of the transformer and also lead to earlier system failure. One of the tests applied is the tan delta test to determine the loss coefficient of the insulating material. A decrease in insulation quality increases the tan delta value. The capacitance value is also measured in the tan delta test. An increased capacitance value indicates the paper insulation has been damaged. Generally, damaged insulation causes a short circuit between capacitor layers which is characterized by an increase in capacitance value. By using the GST-Ground method with the Megger Delta 4110 measuring instrument, the tan delta results of the R, S, and T phases in the southern send bay of Bandung-1 GITET Tasikmalaya are 0.42%, 0.47%, and 0.45%. The results of independent calculations are phase R, S, T are 0.29%, 0.28% and 0.31%. From both results, the current transformer can be said to be feasible to operate because the tan delta value is below 1% which is the operational standard of the current transformer.

Nanodiamond islands confined between two graphene sheets as perspective 2D quantum materials

Based on direct space DFT PBE0/6-31G* electronic structure calculations, the structure and properties of nanodiamond islands confined between two finite graphene fragments (NDI-c2G) was proposed and theoretically explored. DFT simulations revealed that fusion of planar aromatic molecules with two parent graphene fragments may form either cubic or hexagonal allotropes of NDI-c2Gs lattices accompanied with formation of local corrugated sp3 sites with substituted dangling bonds embedded into graphene sublattices. It was shown that at the DFT level of theory, low distortion energies of NDI-c2Gs lattices are comparable or smaller than the energy of van-der-Waals interactions, which allows the NDI-c2G lattices to be stabilized by a support and finally synthesized. The Nuclear Independent Chemical Shift calculations, shows that in the vicinity of NDI regions, graphene lattices are estimated to be either low-, or anti-aromatic. Furthermore, the formation of NDI-c2Gs leads to localization of HOMO and LUMO states at different sites of the NDI-c2Gs lattices. The NDI-c2G regions with confined frontier orbitals can be considered as arrays of quantum dots isolated from each other by NDI scattering centres of 3.82 Å dimension. The results demonstrates that NDI-c2G should be considered as strongly-correlated entangled hybrid quantum dots which may form extended quantum ensembles with great potential for advanced quantum applications.

Verification of an independent dose calculation method for portal-specific QA of proton and carbon ion beams

ObjectiveTo verify the accuracy of an independent dose calculation method, as incorporated into an in-house developed treatment planning system (TPS), for performing quality assurance of dose distributions delivered to a water phantom planned by a clinical TPS. MethodsA Monte Carlo based track repeating algorithm was incorporated into an in-house treatment planning system for proton and carbon ion beams. Calculations were performed in a flat water phantom for both a traditional pencil beam algorithm and a new Monte Carlo algorithm, and then compared to measurements made at multiple depths with a 2D ionization array for 44 patient portals. The comparisons utilized a Gamma analysis. ResultsA total of 124 measurements were performed for proton and carbon ion patient portals. Using a small Gamma criteria of 2%/2 ​mm, an average of 93% and 97% of measurement points passed for each portal for pencil beam and Monte Carlo calculations, respectively. The passing rate was substantially higher for Monte Carlo calculations than for pencil beam calculations for portals that used a range shifter. ConclusionsThe implemented independent method has been verified against measurements. The high passing rate with small tolerances leads to the possibility of reducing the number of required quality assurance measurements.

Virtual patient-specific QA with DVH-based metrics.

We demonstrate a virtual pretreatment patient-specific QA (PSQA) procedure that is capable of quantifying dosimetric effect on patient anatomy for both intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT). A machine learning prediction model was developed to use linear accelerator parameters derived from the DICOM-RT plan to predict delivery discrepancies at treatment delivery (defined as the difference between trajectory log file and DICOM-RT) and was coupled with an independent Monte Carlo dose calculation algorithm for dosimetric analysis. Machine learning models for IMRT and VMAT were trained and validated using 120 IMRT and 206 VMAT fields of prior patients, with 80% assigned for iterative training and testing, and 20% for post-training validation. Various prediction models were trained and validated, with the final models selected for clinical implementation being a boosted tree and bagged tree for IMRT and VMAT, respectively. After validation, these models were then applied clinically to predict the machine parameters at treatment delivery for 7 IMRT plans from various sites (61 fields) and 10 VMAT multi-target intracranial radiosurgery plans (35 arcs) and compared to the dosimetric effect calculated directly from trajectory log files. Dose indices tracked for targets and organs at risk included dose received by 99%, 95%, and 1% of the volume, mean dose, percent of volume receiving 25%-100% of the prescription dose. The average coefficient of determination (r2 ) when comparing intra-field predicted and actual delivery error was 0.987±0.012 for IMRT and 0.895±0.095 for VMAT, whereas r2 when comparing inter-field predicted versus actual delivery error was 0.982 for IMRT and 0.989 for VMAT. Regarding dosimetric analysis, r2 when comparing predicted versus actual dosimetric changes for all dose indices was 0.966 for IMRT and 0.907 for VMAT. Prediction models can be used to anticipate the dosimetric effect calculated from trajectory files and have potential as a "delivery-free" pretreatment analysis to enhance PSQA.

PO-1537 Evaluation of an independent dose calculation software based on AAPM Task Group 219

PO-1537 Evaluation of an independent dose calculation software based on AAPM Task Group 219

Automatic dose verification system for breast radiotherapy: Method validation, contour propagation and DVH parameters evaluation

PurposeImage guided radiotherapy (IGRT) strategies allow detecting and monitoring anatomical changes during external beam radiotherapy (EBRT). However, assessing the dosimetric impact of anatomical changes is not straightforward. In current IGRT strategies dose volume histograms (DVH) are not available due to lack of contours and dose recalculations on the cone-beam CT (CBCT) scan. This study investigates the feasibility of using automatically calculated DVH parameters in CBCTs using an independent dose calculation engine and propagated contours. MethodA prospective study (NCT03385031) of thirty-one breast cancer patients who received additional CBCT imaging (N = 70) was performed. Manual and automatically propagated contours were generated for all CBCTs and an automatic dose recalculation was performed. Differences between planned and CBCT-derived DVH parameters (mean and maximum dose to targets, 95% volume coverage to targets and mean heart dose (MHD)) were calculated using the dose verification system with manual and propagated contours and, in both cases, benchmarked against DVH differences quantified in the TPS using manually contoured CBCTs. ResultsDifferences in DVH parameters between the TPS and dose verification system with propagated contours were −1.3% to 0.7% (95% CI) for mean dose to the target volume, −0.3 to 0.2 Gy (95% CI) in MHD and −3.9% to 2.9% (95% CI) in target volume coverage. ConclusionThe use of an independent fully automatic dose verification system with contour propagation showed to be feasible and sufficiently reliable to recalculate CBCT based DVHs during breast EBRT. Volume coverage parameters, i.e. V95%, proved to be especially sensitive to contouring differences.

Consumer Trust in Mobile Phone Industry: Comparative Study on Traditional Commerce & E-commerce

This paper aims to determine the factors that influence consumers’ decision-making prior to purchasing mobile phones in e-commerce platforms and retail establishments, otherwise known as traditional commerce. Although previous studies have been conducted in understanding consumer trust, this research specifically focuses on a specific industry only, which was a decision made in order to narrow down and better understand the consumer buying behavior, as opposed to having multiple industries which would result in inaccurate findings. Variables used were determined based on related literature leaning towards comparative research, as well as consumer buying behavior. Several methods, including descriptive statistics and independent t-test calculations, have been conducted by the researchers to come up with a conclusion that can assist consumers in having ample knowledge before purchasing a mobile phone on different commerce platforms. The researchers concluded that Traditional commerce is much preferable by the consumers with regards to these factors; credibility perceived ease of use, and satisfaction.

Dosimetric comparison of complete block in ovarian protection between helical tomotherapy and volumetric-modulated arc therapy for cervical cancer

This study is aimed at comparing the dosimetric differences of restricting beamlets passing in protecting ovaries between helical tomotherapy (HT) and volumetric-modulated arc therapy (VMAT) for patients with cervical cancer, and particularly comparing the γ passing rates of ovaries between the two techniques by independent dose calculations. 15 patients with cervical cancer who had undergone ovarian transposition were randomly enrolled. The HT and VMAT plans were created for each involved patient. Target quality, organs at risk (OARs) sparing, and γ passing rates of ovaries were compared between HT and VMAT. HT achieved better than VMAT in D98%, D2%, Dmean, conformal index and homogeneity index (P < 0.05). Almost all OARs in HT had lower radiation dose than those in VMAT (P < 0.05). All the γ passing rates of the ovaries were 100% for the 15 patients both in HT and VMAT. The results suggests that HT outperforms VMAT in terms of target coverage and OARs sparing. Although the calculated dose to the ovaries was accurate both in HT and VMAT, HT showed further advantages for cervical cancer patients with ovarian protection requirements.

Accelerating the finite element method for calculating the full 2-body problem with CUDA

Binary asteroids in solar systems usually have irregularly shaped components; and their internal structures, though lacking direct measurements, are suspected to be uneven given the theoretical considerations of their formation history. This poses a huge challenge to precise dynamic modelling. The finite element method (FEM) is capable of modelling asteroids with irregular shapes and heterogeneous internal structures with good convergence. However, the implementation of the FEM in the full 2-body problem is usually time-consuming for single-core CPU processing. We note that the computing process is comprised of serialized independent calculations that can be parallelized with inexpensive and ubiquitous graphics processing unit (GPU) hardware. We propose a parallel algorithm to accelerate the FEM to calculate the full 2-body problem with CUDA (Compute Unified Device Architecture). Benchmarking tests are performed to verify this method, which is later applied to the study of the motion of the binary asteroid system (66391) 1999KW4. Simulations with more than 10 thousand nodes on a single graphics card exhibit a speedup of up to two orders of magnitude over using a single-core CPU. Both the achieved speedup(s) and the numerical simulation result accuracy suggest that CUDA-based GPU programming can be used in the FEM for computational full 2-body problem methods with efficiency and reliability. As an application, we studied the motion of the binary asteroid system (65803) Didymos, the target object of the DART mission. With the simulation results, we show the influences of the irregular shape/uneven internal structure of the primary on the postimpact motion of the secondary. The code is available at https://github.com/yyu86/femF2BP.git .

Development of an independent MU calculation software for radiotherapy treatments with stereotactic cones.

PurposeDevelopment of an independent MU calculator (StereoCalc) with and without heterogeneity corrections for stereotactic treatments, in a Varian TrueBeam STx LINAC using stereotactic cones, with flattening filter‐free photon energies.MethodsMultiple depth curves and output factors were measured, following the dosimetry formalism for small fields proposed by the TRS‐483. The developed StereoCalc imports and processes the beam data files and calculates the patient plans with and without heterogeneity correction. Validation of the developed software was carried out using phantoms. The accuracy of the StereoCalc software was verified in stereotactic patient plans.ResultsA maximum difference of 2.47% and 2.07% was obtained in the phantom validation tests with and without heterogeneity correction, respectively. The mean percentual difference of StereoCalc from cone dose calculation (CDC) in the clinical testing was 2.86% ±1.27% and 0.78% ±0.48% with and without heterogeneity correction, respectively. The largest differences found were 7.34% and 1.98%, respectively.ConclusionsThe results obtained in this work show that the MU calculated with StereoCalc software is in good agreement with the values calculated by the treatment planning systems, both in static fields and arcs. We have also improved the software to consider heterogeneity corrections calculations. As expected, and as a major achievement of this work, some differences were observed when heterogeneities were considered. StereoCalc proved to be a powerful tool that can be integrated into the specific quality assurance program in a medical physics department for independent verification in stereotactic treatment with cones.