Function Of Depths Research Articles

Assessment of peripheral dose as a function of distance and depth from cobalt-60 beam in water phantom using TLD-100

BackgroundInnovations in cancer treatment have contributed to the improved survival rate of cancer patients. The cancer survival rates have been growing and nearly two third of those survivors have been exposed to clinical radiation during their treatment. The study of long-term radiation effects, especially secondary cancer induction, has become increasingly important. An accurate assessment of out-of-field/peripheral dose (PDs) is necessary to estimate the risk of second cancer after radiotherapy and the damage to the organs at risk surrounding the planning target volume. This study was designed to measure the PDs as a function of dose, distances, and depths from Telecobalt-60 (Co-60) beam in water phantom using thermoluminescent dosimeter-100 (TLD-100).MethodsThe PDs were measured for Co-60 beam at specified depths of 0 cm (surface), 5 cm, 10 cm, and 15 cm outside the radiation beam at distances of 5, 10, and 13 cm away from the radiation field edge using TLD-100 (G1 cards) as detectors. These calibrated cards were placed on the acrylic disc in circular tracks. The radiation dose of 2000 mGy of Co-60 beam was applied inside 10 × 10 cm2 field size at constant source to surface distance (SSD) of 80 cm.ResultsThe results showed maximum and minimum PDs at surface and 5 cm depth respectively at all distances from the radiation field edge. Dose distributions out of the field edge with respect to distance were isotropic. The decrease in PDs at 5 cm depth was due to dominant forward scattering of Co-60 gamma rays. The increase in PDs beyond 5 cm depth was due to increase in the irradiated volume, increase in penumbra, increase in source to axis distance (SAD), and increase in field size due to inverse square factor.ConclusionIt is concluded that the PDs depends upon depth and distance from the radiation field edge. All the measurements show PDs in the homogenous medium (water); therefore, it estimates absorbed dose to the organ at risk (OAR) adjacent to cancer tissues/planning target volume (PTV). It is suggested that PDs can be minimized by using the SAD technique, as this technique controls sources of scattered radiation like inverse square factor and effect of penumbra up-to some extent.

Short-term retention of words as a function of encoding depth.

The traditional short- and long-term storage view of information processing and the levels-of-processing view both discuss the forgetting of information over time. In the traditional stage view, there is loss of at least poorly encoded information across several seconds when the information cannot be rehearsed (e.g., Ricker et al., 2020, Learning, Memory, and Cognition, 46, 60-76). In the levels-of-processing approach, information that is encoded in a shallow manner is lost more quickly over time than deeply-encoded information (Craik & Lockhart, 1972, Journal of Verbal Learning and Verbal Behavior, 11, 671-684.). Previous studies of the depth of encoding, however, have mostly been conducted using delayed tests, so there are few studies directly comparing the rate of forgetting over time for information as a function of different depths of encoding. We manipulated the level of processing with immediate recall in a modified Brown-Peterson task. An effect of the level of processing was robust, but evidence of forgetting across retention intervals was not always observed. When encoding time was curtailed (in Experiments 3 and 4), we found main effects of both the level of processing and the retention interval, but no interaction between the two variables. The results suggest that the depth-of-encoding effect may occur during the initial encoding of items, but without differential forgetting within the range of retention intervals that we examined (0-18 s), in contrast to the suggestion by Craik and Lockhart. Further work is needed to determine whether the depth-of-processing effect would grow over longer intervals.

Irrigation management of Punica granatum in the Sub-Middle São Francisco River Valley: Morphophysiological aspects.

Water availability in arid and semi-arid areas has been a limiting factor to the expansion of agricultural production in several regions of the world. In this context, this research aimed to study the morphophysiological responses of pomegranate as a function of different irrigation depths in the Sub-Middle São Francisco River Valley (SSFV). The research was carried out in a commercial area located in Petrolina-PE, Brazil, with eight-year-old plants of lineage No. 12 of Embrapa Semi-Arid, spaced 4.0 x 2.0 m. Drip irrigation with a flow of 2.4 L h−1 emitter−1 was used every two days. The treatments consisted of D50 – continuous irrigation deficit with 50% ET0 replacement, D75 – continuous irrigation deficit with 75% ET0 replacement, D100 – continuous irrigation deficit with 100% ET0 replacement, and DF – farm irrigation. The experiment was conducted in randomized blocks with five replications. Plant height, cup diameter, number of flower buds, flowers, and fruits, relative chlorophyll content, free proline content in the leaves, gas exchange, water potential in the branch, and soil moisture were evaluated. The data were submitted for analysis of variance and regression at the 5% probability level, using the Sisvar program. We observed that the analyzed pomegranate can avoid excessive water loss to the atmosphere when subjected to water stress using different mechanisms. Moreover, the deficit of irrigation depths led to an anticipation and/or uniformity of flowering.

Effect of depth ratio on Faraday instability in a binary liquid system

The response of two incompressible and immiscible liquids of comparable densities at different depth ratios in a rectangular container subject to parametric sinusoidal forcing, similar to Faraday waves, has been considered in the present study. The effect of various depth ratios on the instability threshold and the flow field are investigated for (0, 2) and (0, 4) modes. Numerical simulation has been performed using OpenFOAM to solve Navier-Stokes equations. A source term is added in the interFoam module of OpenFOAM to take the effect of the oscillating container without using any dynamic mesh function. The threshold amplitude and wavenumbers are validated following the linear Floquet analysis of Kumar and Tuckerman (1994 J. Fluid Mech. 279 49–68). The Floquet analysis showed a substantial shift in natural frequency (reduction) and an increase in threshold amplitude when the interface is in close proximity to the wall. The response amplitude follows a square law with the forcing amplitude for all the depth ratios considered in the present study. The wave amplitude response above the threshold curve is found to be an exponential function of liquid depths and forcing parameters.

Water-Retaining Polymer and Planting Pit Size on Chlorophyll Index, Gas Exchange and Yield of Sour Passion Fruit with Deficit Irrigation.

Water availability is a limiting factor for the cultivation of sour passion fruit. Soil management techniques and the use of water-retaining polymers can increase soil water retention, reducing the frequency of irrigation in the crop. In this context, the objective of the research was to evaluate the gas exchange, the chlorophyll index, and the yield of the sour passion fruit cv. BRS GA1 as a function of irrigation depths, pit volumes, and doses of water-retaining polymer. The experiment was carried out in randomized blocks, in plots subdivided in a 2 × (2 × 5) arrangement, with irrigation depths of 70 and 100% of the crop evapotranspiration (ETc) as the main plot, the subplots with the volumes of pit of 64 and 128 dm3, and doses of the water-retaining polymer of 0, 0.5, 1.0, 1.5, and 2.0 g dm-3. The interaction of irrigation depths × pit volumes × doses of water-retaining polymer influences chlorophyll indexes, gas exchange, and water productivity, with positive impacts on yield of the sour passion fruit. The water depth of 70% of ETc increased the yield of sour passion fruit, in pits of 64 dm3. The application of doses of up to 1.1 g dm-3 of the water-retaining polymer and irrigation with water of 70% of ETc is recommended, and a dose of 2.0 g dm-3 of the water-retaining polymer in a pit volume of 128 dm3, associated with an irrigation depth of 100% ETc causes stress in sour passion fruit plants due to excess water.

Characterization of a 5 mm thick CZT-Timepix3 pixel detector for energy-dispersive γ-ray and particle tracking

The present manuscript describes a comprehensive characterization of a novel highly segmented 5 mm CZT sensor attached to Timepix3. First, the sensor’s IV curve was measured and basic sensor characterization was done with laboratory γ-radiation sources. The sensor resistivity was determined to be (0.155± 0.02) GOhm · cm. The sensor showed decent homogeneity, both for the per-pixel count rate and electron mobility-lifetime product μ e τ e. The latter was measured to be = 1.3 × 10−3 cm2/V with a standard deviation σ = 0.4 × 10−3 cm2/V describing the dispersion of values for different pixels. The basic sensor characterization is complemented by measurements at grazing angle in a 120 GeV/c at the CERN’s Super Proton Synchrotron. The penetrating nature of these particles together with the pixelation of the sensor allows for a determination of the charge collection efficiency (CCE), as well as charge carrier drift properties (drift times, lateral charge cloud expansion) as a function of the interaction depths in the sensor. While CCE drops by 30%–40% towards the cathode side of the sensor, from the drift time dependency on interaction depth, the electron mobility μ e was extracted to be (944.8 ± 1.3) cm2/V/s and τ e = (1.38 ± 0.31) μs. The spectroscopic performance was assessed in photon fields and extracted from energy loss spectra measured at different angles in the pion beam. While at photon energies below 120 keV incomplete charge collection leads to an underestimation of the photon energy when irradiated from the front-side, at higher energies the relative energy resolution was found to be ∼4.5%, while a relative energy resolution of ∼7.5% was found for the particle energy loss spectra. It is shown that the drift time information can be used to reconstruct particle interactions in the sensor in 3D, providing a spatial resolution of σ xyz = 241 μm within the sensor volume and a particle trajectory measurement precision Δxyz = 100 μm, at a distance of 1 m from the sensor. We demonstrate by measurement with a 22Na source, that the energy resolution combined with the 3D reconstruction allows for detection of γ-ray source location and polarity using Compton scattering within the sensor (Compton camera and scatter polarimeter).

Modified Generalized R/T Coefficient Method for Surface-Wave Dispersion-Curve Calculation in Elastic and Viscoelastic Media

ABSTRACT This article presents an efficient and effective modified generalized reflection and transmission (R/T) (mGRT) coefficient method for dispersion-curve calculation of the Rayleigh and Love waves. We construct a novel dispersion function based on the kernel function for calculating synthetic seismograms in an elastic layered half-space model. It improves the root searching using the monotonicity of the dispersion function in sections between roots. We introduce an auxiliary function to accelerate the root-searching procedure by approximating the number of roots of the dispersion equation. To solve the low-velocity-layer problem for the generalized R/T coefficient method, we turn to the dispersion function of multiple depths. Numerical results indicate that the proposed method is slightly slower than the other most efficient methods including the delta-matrix method and the fast delta-matrix method. Then, we present a technique for the velocity and attenuation dispersion curves in viscoelastic media. The technique is based on jumping features of the dispersion function and converts 2D root-searching problem to 1D minimization problem. The mGRT method is expected to be a useful candidate for calculating dispersion curves in both elastic and viscoelastic media.

Layer-by-Layer Organic Photovoltaic Solar Cells Using a Solution-Processed Silicon Phthalocyanine Non-Fullerene Acceptor.

Silicon phthalocyanines (SiPcs) are promising, inexpensive, and easy to synthesize non-fullerene acceptor (NFA) candidates for all-solution sequentially processed layer-by-layer (LbL) organic photovoltaic (OPV) devices. Here, we report the use of bis(tri-n-butylsilyl oxide) SiPc ((3BS)2-SiPc) paired with poly(3-hexylthiophene) (P3HT) and poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo[1,2-b:4,5-b′]dithiophene))-alt-(5,5-(1′,3′-di-2-thienyl-5′,7′-bis(2-ethylhexyl)benzo[1′,2′-c:4′,5′-c′]dithiophene-4,8-dione))] (PBDB-T) donors in an LbL OPV structure. Using a direct architecture, P3HT/(3BS)2-SiPc LbL devices show power conversion efficiencies (PCEs) up to 3.0%, which is comparable or better than the corresponding bulk heterojunction (BHJ) devices with either (3BS)2-SiPc or PC61BM. PBDB-T/(3BS)2-SiPc LbL devices resulted in PCEs up to 3.3%, with an impressive open-circuit voltage (Voc) as high as 1.06 V, which is among the highest Voc obtained employing the LbL approach. We also compared devices incorporating vanadium oxide (VOx) or poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as a hole transporting layer and found that VOx modified the donor layer morphology and led to improved Voc. Probing the composition as a function of film layer depths revealed a similar distribution of active material for both BHJ and LbL structures when using (3BS)2-SiPc as an NFA. These findings suggest that (3BS)2-SiPc is a promising NFA that can be processed using the LbL technique, an inherently easier fabrication methodology for large-area production of OPVs.

Convection of water vapour in snowpacks

This paper studies numerically the convection of water vapour in snowpacks using an Eulerian–Eulerian two-phase approach. The convective water vapour transport in snow and its effects on snow density are often invoked to explain observed density profiles, e.g. of thin Arctic snow covers, but this process has never been numerically simulated and analysed in a systematic manner. Here, the impact of convection on the thermal and phase change regimes as a function of different snowpack depths, thermal boundary conditions and Rayleigh numbers is analysed. We find considerable impact of natural convection on the snow density distribution with a layer of significantly lower density at the bottom of the snowpack and a layer of higher density located higher in the snowpack or at the surface. We find that emergent heterogeneity in the snow porosity results in a feedback effect on the spatial organization of convection cells causing their horizontal displacement. Regions where the snowpack is most impacted by phase changes are found to be horizontally extended and vertically thin, ‘pancake’-like layers at the top and bottom of the snowpack. We further demonstrate that among the parameters important for natural convection, the snowpack depth has the strongest influence on the heat and mass transfer. Despite our simplifying assumptions, our study represents a significant improvement over the state of the art and a first step to accurately simulate snowpack dynamics in diverse regions of the cryosphere.

Simulating the γ-ray and neutron attenuation properties of lithium borate glasses doped barite: efficient and deterministic analysis using relevant simulation codes

In the present paper, we report a comprehensive theoretical study dealing with γ -ray, fast and thermal neutrons shielding features of compositionally graded Pb-free lithium borate glasses doped barite: (B2O3)(0.6)(BaSO4)(x)(Li2O)(0.4-x). The study has been conducted for six particular values of the LiO2 fraction x namely x = 0.0, 0.05, 0.075, 0.1, 0.15, and 0.2 in mol%. This choice finds its origin with the circumstance of getting nontoxic glasses characterized by a strong X/β -ray absorption. WinXCOM program was used to determine mass attenuation coefficients μ/ρ by means of a photon energy ranging from 0.015 to 15 MeV. The obtained results are compared with those evaluated with Geant4, and Penelope codes. To illustrate the key physical parameters of all glasses, namely the effective electron density (Neff), γ -ray attenuation parameters like effective atomic number (Zeff), half-value layer (HVL), as well as the mean free path (MFP) and their corresponding potential functionality, we utilize the μ/ρ values of WinXCOM assessed within a range of photon energy varying from 0.015 to 15 MeV. We also investigate the impact of the exposure buildup factors (EBFs) as well as the energy absorption buildup factors (EABFs) by performing a geometric progression (G–P) fitting method as a function of varied penetration depths ranging from 1 to 40 mfp by step of 5 mfp. Additionally, the mass stopping power (MSP) and projected range (PR) have been estimated for alpha particles and triton particles using SRIM code within 0.01–1 MeV energy range. The results obtained herein reveal that the glass G20 is demonstrating its endorsement of a prime γ -ray shielding effectiveness among the rest of glasses. We also proven through our numerical simulations that the glass G00 possess the relatively larger macroscopic removal cross-section for fast neutrons attenuation as well as the significant thermal neutrons absorption cross-section, in addition to the fact it holds the highest mass stopping power (MSP) and lowest projected range (PR), suggesting thereby its superior neutronic, tritonic and alpha shielding abilities.

Calibration of a 3D hydrodynamic model for a hypertidal estuary with complex irregular bathymetry using adaptive parametrization of bottom roughness and eddy viscosity

This study introduces a new scheme to make both turbulence and flow resistance modeling a dynamic function of tidal water depths and flow direction. The k−ε turbulence model is continuously adapted to local depth conditions and the Manning n bed roughness values are continuously made locally dependent on the direction of flow. Turbulence structure, production, and attenuation in estuaries are highly influenced by the fact that the flow occurs in ‘shallow water’. In hypertidal estuaries with complex bathymetries, the depths are highly variable in both time and space. In this paper, an adaptive correction scheme is introduced to dynamically adjust (in time and space) the k−ε turbulence model as a function of local flow depth. Furthermore, in the flow reversal portions of tidal rivers, flow direction changes cyclically during flood tides and ebb tides. This causes a direction-based pattern of bedforms that significantly affects the directional values of hydrodynamic bed resistance (Manning n). In this paper, an adaptive scheme accounts for flow directionality. The modifications are incorporated into a three-dimensional numerical hydrodynamic model (Delft3D). The resulting simulated water levels of the Koksoak hypertidal estuary are presented and are demonstratively in better agreement with observations than water levels simulated when not using the corrections. The results suggest that the proposed schemes can improve the accuracy of the turbulence and bed roughness models for simulations of shallow hypertidal estuarine flows with complex river bathymetries.

Investigation of Silicon Solar Cells under Submerged Conditions with the Influence of Various Parameters: A Comparative Study

Solar photovoltaic (PV) is one of the emerging technologies in underwater power systems such as water monitoring and sensing devices in marine environments. Harnessing the underwater solar energy is a massive advantage because of the abundant amount of solar energy and space covered by water on the surface of the Earth. Currently, the utilization of underwater solar PV systems has several issues such as cooling, cleaning, and land constraints facing in terrestrial conditions. Still, the PV systems has the ability to operate in underwater environments and to interface with other marine power systems in a hybrid manner. Therefore, there is a need to further study and understand the utility of solar PV in underwater conditions. Herein, a comparative analysis on underwater solar radiation and the performance of various silicon solar cells using different water conditions, in a controlled indoor atmosphere, are carried out. The propagation of solar radiation underwater is investigated as a function of water depths and changing water settings such as in the presence of dissolved salts and solids. This work demonstrates that the solar energy in water can also be extracted with solar PV cells to produce electricity for several industrial, defense, naval, and marine applications.

Dependence of the Photosynthetic Quantum Yield on Phytoplankton Light Absorption: Equations for Assessing Primary Production in the Black Sea

Purpose. Investigations were performed during a scientific cruise to characterize hydrophysical properties, chlorophyll a concentration, photosynthesis-irradiance curves, spectral light absorption coefficients by phytoplankton, and spectral quantum downwelling irradiance. From these results, the dependence of the photosynthetic quantum yield upon environmental factors was studied with the purpose of adapting an algorithm developed for the Baltic Sea so that it can be applied for the Black Sea. Methods and Results. Complex hydrophysical and biological studies were carried out at several depths within the euphotic zone. Spectral bio-optical parameters were measured in accordance with the latest NASA protocols (2018). Experiments to determine the photosynthesis-light relationship were performed under temperature and light conditions similar to those in situ. The quantum yield of photosynthesis was calculated from parameters of photosynthesis-light curves (photosynthesis efficiency, light saturation parameter) and the spectral light absorption coefficients by phytoplankton pigments. It was found out that the main photosynthetic characteristics of phytoplankton, including the maximum photosynthetic quantum yield and the fraction of phytoplankton absorption associated with photoprotective accessory pigments, varied with depth within the euphotic zone, due to phytoplankton acclimation to environment factors during the period of seasonal stratification. The relationship between the photosynthetic quantum yield and the quanta absorbed by photosynthetically active phytoplankton pigments was revealed. The results of this research made it possible to build on the approach developed for other regions and modify the equation for calculating the quantum yield to apply specifically for environmental conditions in the Black Sea. Conclusions. For the first time, comprehensive studies carried out in the Black Sea, including measurements of the photosynthesis-light dependence, spectral light absorption coefficients by phytoplankton and spectral downwelling irradiance as a function of optical depths within the euphotic zone, made it possible to reveal the equation for calculating photosynthetic quantum yield. This new equation can be applied for calculating primary production of the Black Sea using a spectral approach, based both on the results of in situ measurements and remote sensing data.

Confocal Raman depth imaging tracking on the diffusion process of single and two-component reactive dyes in a single viscose fiber

Confocal Raman microscopy (CRM) was used as a non-destructive tool for in situ investigations of the diffusion process of C.I. Reactive Blue 194 (RB194) and C.I. Reactive Yellow 176 (RY176) in single fibers. Mapping along the radius of the fiber was performed. The distribution of dye in the fiber at different adsorption time was observed. A significant dye concentration gradient was obtained along the line normal to the fiber surface to a depth of 6 μm as a function of depths. The diffusion process of a single dye with different initial concentrations in fibers was first studied. The results showed that the diffusion rate of dyes in the fiber is mainly affected by the initial dye concentration and the affinity between dye and fiber. In the mixed dyes, RB194 having a higher affinity with fiber is less affected by other factors, and its diffusion rate in the fiber mainly depends on the driving force provided by it concentration difference. The diffusion of RY176 with lower affinity and easier aggregation in fiber is easily affected by other factors, such as concentration or other components in color matching. In this study, RB194 in the mixed component has a strong promotion effect on the diffusion of RY176 in the fiber. The distribution of dye in the fiber can judge the permeability and uniformity of the fabric during dyeing. The diffusion properties of different dyes in the fiber can be analyzed more directly and accurately to promote the design and development of dye molecular structure.

Lixiviação de diferentes formulações de clomazone em resíduos de cana-de-açúcar

O objetivo do presente estudo foi avaliar a lixiviação de diferentes formulações de clomazone em função da densidade da palhada e diferentes lâminas de irrigação. Os experimentos foram conduzidos em delineamento inteiramente casualizado, em esquema fatorial 2 x 6, com quatro repetições. O experimento I utilizou dois herbicidas Gamit (1.260 g ha-1 de clomazone) e Gamit 360 CS (1.260 g ha-1 de clomazone microencapsulado), seis densidades de palhada (0, 5, 10, 15, 20, 25 t ha-1). Para o experimento II utilizou-se dois herbicidas Gamit (1.260 g ha-1 de clomazone) e Gamit 360 CS (1.260 g ha-1 de clomazone microencapsulado), seis lâminas de irrigação (5, 10, 15, 20, 25 e 30 mm). Realizou-se avaliações visuais da porcentagem de intoxicação aos 7, 14, 21 e 28 dias, a matéria seca foi determinada aos 28 dias. A porcentagem de intoxicação em solos contaminados com lixiviado de herbicida em diferentes densidades de palhada (0 e 5 t ha-1) se manteve iguais para os herbicidas clomazone na formulação convencional e microencapsulada. Todavia, quando em formulação microencapsulado observou-se nível de intoxicação entorno de 90% demonstrando a capacidade que este tem para transpor acamada de palhada. O incremento da lâmina de água proporcionou a maior transposição do herbicida pela barreira física imposta pela palha, o que refletiu no incremento da porcentagem de controle. Concluiu-se que a lixiviação do clomazone quando em formulação microencapsulada é maior que em formulações convencionais, independente da barreira física imposta pela palhada e pela lâmina de água aplicada.

Microdosimetric measurements of a monoenergetic and modulated Bragg Peaks of 62MeV therapeutic proton beam with a synthetic single crystal diamond microdosimeter.

The purpose of this study was to investigate for the first time the performance of a synthetic single crystal diamond detector for the microdosimetric characterization of clinical 62MeV ocular therapy proton beams. A novel diamond microdosimeter with a well-defined sensitive volume was fabricated and tested with a monoenergetic and spread-out Bragg peak (SOBP) of the CATANA therapeutic proton beam in Catania, Italy. The whole sensitive volume of the detector has an active planar-sectional area of 100µm×100µm and a thickness of approximately 6.3 um. Microdosimetric measurements were performed at several water equivalent depths, corresponding to positions of clinical relevance. From the measured spectra, microdosimetric quantities such as the frequency mean lineal energy ( ), dose mean lineal energy ( ) as well as microdosimetric relative biological effectiveness (RBEµ ) values were derived for each depth along both a pristine Bragg curve and SOBP. Finally, Geant4 Monte Carlo simulations were performed modeling the detector geometry and CATANA beamline in order to calculate the average linear energy transfer (LET) values in the diamond active layer and water. The microdosimetric spectra acquired by the diamond microdosimeter show different shapes as a function of the water equivalent depths. No spectral distortion, due to pile-up events and polarization effects, was observed. The experimental spectra have a very low detection threshold due to the electronic noise during the irradiation of about 1keV/μm. The and values were in agreement with expected trends, showing a sharp increase in mean lineal energy at the distal edge of the Bragg peak. In addition, a good agreement between the mean lineal energy values and the calculated average LET ones was also observed. Finally, the RBE values evaluated with the diamond microdosimeter were in excellent agreement with those obtained with a mini tissue equivalent proportional counter as well as with radiobiological measurements in the same proton beam field. The microdosimetric performance of the tested synthetic single crystal diamond microdosimeter clearly indicates its suitability for quality assurance in clinical proton therapy beam.

TeO2–B2O3–ZnO–La2O3 glasses: γ-ray and neutron attenuation characteristics analysis by WinXCOM program, MCNP5, Geant4, and Penelope simulation codes

γ-ray, fast and thermal neutrons shielding features for five Pb-free {[(TeO2)0.70(B2O3)0.30]0.7 (ZnO)0.30}(1-x)(La2O3)x (x = 0.01, 0.02, 0.03, 0.04, and 0.05 mol%) glasses have been inspected in this work. For all samples, within the photon energy range of 0.015–15 MeV, linear attenuation coefficients (μ) and mass attenuation coefficients (μ/ρ) were estimated using WinXCOM program (theoretical approach), and obtained μ/ρ values are in fine agreement with computed μ/ρ results of respective MCNP5, Geant4, and Penelope codes. By utilizing μ/ρ values of WinXCOM, γ-ray attenuation parameters like effective atomic number (Zeff), effective electron density (Neff), half-value layer (HVL), and mean free path (MFP) were assessed within 0.015–15 MeV photon energy range, for all samples. Additionally, exposure buildup factors (EBFs) and energy absorption buildup factors (EABFs) were calculated for all samples by applying a five parameter geometric progression (G‒P) fitting method as a function of various penetration depths (1, 5, 10, 15, 20, 25, 30, 35, and 40 mfp) within 0.015–15 MeV photon energy range. The derived radiation protection efficiency (RPE) results indicate all samples' effective attenuation competence for lower energy γ-rays. Among all glasses, 46.55TeO2-19.95B2O3-28.5ZnO–5La2O3 (mol%) sample, by having relatively bigger μ/ρ and Zeff, minimal HVL and MFP, and lowest EBF and EABF, endorse its' excellent γ-ray shielding effectiveness. Further, neutron shielding parameters such as macroscopic removal cross-section for fast neutrons (ΣR), coherent and incoherent scattering cross-sections (σcs & σics), absorption cross-section (σA), and total cross-section (σT) for thermal neutrons were explored. By using the Geant4 code, ‘σT’ values have been deduced within 10−4‒10−8 MeV neutron energy range. The 46.55TeO2-19.95B2O3-28.5ZnO–5La2O3 (mol%) glass owns relatively larger ΣR (0.1474 cm−1) for fast neutrons attenuation and ‘σT’ (10.1444 cm−1 at 0.0253 eV neutron energy, 15.9824 cm−1 → 0.551 cm−1 from 1 × 10−8 MeV →1 × 10−4 MeV neutron energy) for thermal neutrons absorption, respectively, revealing its' superior neutrons shielding ability.

B2O3–Bi2O3–TeO2–BaO and TeO2–Bi2O3–BaO glass systems: a comparative assessment of gamma-ray and fast and thermal neutron attenuation aspects

For Pb-free 35B2O3‒35Bi2O3‒(30–x)TeO2‒(x)BaO (x = 5, 10, 15, 20, and 25 mol%) and (90–x)TeO2‒10Bi2O3‒(x)BaO (x = 10, 15, and 20 mol%) glass systems, gamma and neutron (both fast and thermal neutron) radiation shielding features were examined and compared. Within 0.015–15 MeV photon energy, mass attenuation coefficients (μ/ρ), for all samples, which have been assessed using WinXCOM program are in fair agreement with deduced MCNP5 simulation code μ/ρ results. For all selected samples, at the lowest energy, μ/ρ has bigger values whereas at higher energy regions possess lower values. Furthermore, by employing μ/ρ values, effective atomic number (Zeff), effective electron density (Neff), half-value layer (HVL), tenth-value layer (TVL), and mean free path (MFP) are figured out for both glass systems. For studied samples, with the gradual replacement of TeO2 content with BaO, the derived values of Zeff, HVL, TVL, and MFP revealed improved γ-ray shielding potentiality. Besides, within photon energy range of 0.015–15 MeV, exposure build-up factors (EBFs) and energy absorption build-up factors (EABFs) were estimated for all samples by utilizing G‒P fitting method as a function of different penetration depths (0.5, 1, 2, 3, 4, 5, 6, 7, 8, 10, 15, 20, 25, 30, 35, and 40 mfp). The 35B2O3–35Bi2O3–5TeO2–25BaO (mol%) glass relatively larger μ/ρ and Zeff values, lower HVL, TVL, and MFP values, and minimal EBF and EABF values confirm its superior γ-ray attenuation competence among all samples. Additionally, in comparison, HVL and MFP values of 35B2O3–35Bi2O3–5TeO2–25BaO (mol%) sample are lower than the respective values of some commercial γ-ray shielding glasses and different types of standard concretes, signifying its better shielding features than them. Moreover, macroscopic removal cross-section for fast neutrons (ΣR), coherent scattering cross-section (σcs), incoherent scattering cross-section (σics), absorption cross-section (σA), and total cross-section (σT) for thermal neutrons absorption were derived for both glass systems. Among all selected glasses, 35B2O3–35Bi2O3–5TeO2–25BaO (mol%) sample possesses relatively higher ΣR (0.106 cm−1) and ‘σT’ (8.809 cm−1 at 0.0253 eV neutron energy) values for fast and thermal neutrons attenuation, respectively, demonstrating its favorable absorption capability for neutrons.

Image-based extrusion with realistic surface wrinkles

Abstract Per-pixel extrusion mapping is an image-based modeling and rendering technique that can be used in a large variety of computer graphic applications. This technique makes it possible to create geometries without polygonal meshes by extrusion of a basic form stored in a 2D binary image. It is available in four versions: basic extrusion, outward extrusion, beveled extrusion, and chamfered extrusion, and all allow the production of satisfactory results in terms of interactivity or visual quality. The problem is that the extruded surfaces do not exhibit microrelief effects and have a lack of realistic superficial wrinkles. To solve this problem, we proposed in this paper a combination of the per-pixel extrusion mapping and the bump mapping in order to add a microrelief effect to extruded surfaces without changing the basic geometry. For the real-time synchronization between the depth scaling of the microreliefs and the resulting shading, we proposed to use a scale factor to further disturb the normal in a function of depths.

Evaluation of Brightness Temperature Sensitivity to Snowpack Physical Properties Using Coupled Snow Physics and Microwave Radiative Transfer Models

There are multiple existing microwave radiative transfer models (RTMs) to simulate the brightness temperature (Tb) of snowpacks. It is still challenging to have consistent Tb responses from RTMs due to individual physical formulations of the snowpack scattering process. This article examines three of the widely-used multi-layer RTMs: 1) the microwave emission model of layered snowpacks (MEMLS); 2) the dense media radiative transfer based on the quasi-crystalline approximation (QCA) of Mie scattering of densely packed sticky spheres (DMRT-QMS); and 3) the Helsinki University of Technology (HUT) model. Interestingly, these models yield slightly different Tb responses when driven by the same physical snowpack properties. Tb variations, dependent on the choice of RTMs, are then evaluated to improve the understanding of model differences in microwave emission from a snowpack. We first perform a sensitivity study of the Tb predictions from the three RTMs as a function of snow grain sizes, densities, and depths. While Tb from all three RTMs decreases with increasing snow grain sizes, it is found that a scaling factor is required to have the same amount of Tb attenuation for small grain sizes within the Rayleigh scattering regime. For larger grain sizes, however, a scaling coefficient is not enough to match the model outputs due to the different scattering assumptions of the RTMs. For a single snow layer with increasing snow depths and densities, all three RTMs exhibit Tb attenuations arising from the increase in path lengths and optical depths. Further evaluations are conducted by feeding the three RTMs with the output of a snow physics model driven by in situ weather forcing in a coupled simulation. Outputs of this coupled model include snowpack physical properties and Tbs. By using snow stratigraphy observations, another set of Tb simulation is also conducted with RTMs driven by in situ snowpit observations. The snow physics outputs from the coupled case are compared against in situ snow stratigraphy observations. And both Tb simulations are compared against ground-based microwave observations from the European Space Agency (ESA) Nordic Snow Radar Experiment (NoSREx) 2009–2012. For three consecutive years, the in situ driven Tbs have 21.0-K root-mean-squared error (RMSE) while the coupled simulations have 24.7-K RMSE. However, after isolating the dry snow period and excluding diurnal melting snow conditions, 12.2- and 6.3-K RMSEs are achieved from in situ and coupled cases, respectively, in the 2011 water year.