Solid Water Research Articles

An Ice Loss Evaluation of Lake-Terminating Glaciers Based on Lake Bathymetry—A Case Study of the Jiongpu Glacier

Lake-terminating glaciers are among the most severely retreating glacier types in high mountain areas. However, the characteristic of being covered by glacial lakes after retreat makes it hard to estimate their actual ice loss in recent years, as does the contribution of different parts in ice loss, which leads to significant obstacles not only in evaluating solid water resources but understanding inter-relationships between glacial ice and glacial lakes. This study presents a detailed investigation of Jiongpu Co, one of the biggest glacial lakes in the Tibetan Plateau, including its bathymetry and area evolution. The ice loss in the last two decades was analyzed using a multisource DEM dataset. The main results showed that from 1976 to 2021, Jiongpu Co had expanded from 1.19 ± 0.09 km2 to 5.34 ± 0.07 km2. The volume of Jiongpu Co showed a surprising increment from 0.09 ± 0.004 Gt to 0.66 ± 0.03 Gt from 1976 to 2021, leading to a subaqueous equivalent ice loss of 0.32 ± 0.01 Gt water from 2000 to 2020 and resulting in an underestimated ice loss of 0.06 Gt, 19% compared with previous evaluations. The total ice loss of the Jiongpu glacier was 1.52 ± 0.37 Gt from 2000 to 2020, and more than 1/3 ice loss was related to lake expansion (0.32 ± 0.01 Gt underwater, 0.19 ± 0.02 Gt above water). This study makes a further contribution to the understanding of ice loss in the complicated system of lake-terminating glaciers.

The accuracy of Eclipse AXB and AAA dose algorithms with dental amalgam.

High-density materials used for dental restorations are poorly defined in CT imaging due to scanner limitations. Studies have established that Eclipse offers poor agreement with delivered dose in situations involving high-density material. Defining the accuracy of dose algorithms in situations involving high-density overrides would improve clinical outcomes both for target coverage and OAR sparing. Dental amalgam was placed within a solid water phantom and measurements were taken at 1cm increments beneath the amalgam down to a depth of 6cm. Exposed film was compared with Eclipse Treatment Planning system (TPS) calculations on a CT of the experimental setup. The amalgam was overridden with a range of HU values and material selections for dose calculation. AXB performs poorly at describing depth dose downstream of Amalgam, regardless of the override material selected. Query ID="Q2" Text="Please confirm the section headings are correctly identified." Applying the known mass density with the Anisotropic Analytical Algorithm (AAA) predicts an average of 1.8% and 2.8% for 6 MV and 10 MV beams. The closest agreement achieved using the Acuros XB (AXB) was overriding with stainless steel, which predicted approximately 1.1% and 1.8% above measured dose for 6 MV and 10 MV respectively. Without overriding the density of amalgam, AAA and AXB return depth dose predictions of 7.3% and 5.8% above film measurement for a 6 MV and 7.6% and 6.5% for 10 MV static beams. Applying override options to a clinical case using an anthropomorphic phantom showed using AXB with Stainless Steel as amalgam override returns the same results as AAA with mass density applied for amalgam. Both of these were in close agreement to the TPS.

Operational and experimental snow observation systems in the upper Rofental: data from 2017 to 2023

Abstract. This publication presents a comprehensive hydrometeorological data set for three research sites in the upper Rofental (1891–3772 m a.s.l., Ötztal Alps, Austria) and is a companion publication to a data collection published in 2018. The time series presented here comprise data from 2017 to 2023 and originate from three meteorological and snow hydrological stations at 2737, 2805, and 2919 m a.s.l. The fully equipped automatic weather stations include a specific set of sensors to continuously record snow cover properties. These are automatic measurements of snow depth, snow water equivalent, volumetric solid and liquid water contents, snow density, layered snow temperature profiles, and snow surface temperature. One station is extended by a particular arrangement of two snow depth and water equivalent recording devices to observe and quantify wind-driven snow transport. These devices are installed at nearby wind-exposed and sheltered locations and are complemented by an acoustic-based snow drift sensor. We present data for temperature, precipitation, humidity, wind speed, and radiation fluxes and explore the continuous snow measurements by combined analyses of meteorological and snow data to show typical seasonal snow cover characteristics. The potential of the snow drift observations is demonstrated with examples of measured wind speeds, snow drift rates, and redistributed snow amounts during several blowing snow events. The data complement the scientific monitoring infrastructure in the research catchment and represent a unique time series of high-altitude mountain weather and snow observations. They enable comprehensive insights into the dynamics of high-altitude meteorological and snow processes and are collected to support the scientific community, local stakeholders, and the interested public, as well as operational warning and forecasting services. The data are publicly available from the GFZ Data Services repository: https://doi.org/10.5880/fidgeo.2023.037 (Department of Geography, University of Innsbruck, 2024).

Non-Stationary Effects of Current-Load on Electrochemical Behavior of La0.8Sr0.2MnO3- δ in Solid Oxide Electrolysis Cell

High-temperature solid oxide water electrolysis is a highly efficient and carbon-free technology employed for energy conversion, offering numerous advantages over traditional low-temperature water electrolysis methods. These benefits include fast electrode kinetics without the need for Pt group metals and the potential to operate in reversible regimes (fuel cell/steam electrolysis), attributed to the elevated operating temperature (i.e., 600-800 °C). However, the high operating temperature imposes stringent material requirements.While recent attention has been directed towards developing and characterizing new materials for both electrodes and electrolytes, a comprehensive understanding of the underlying reaction mechanisms remains incomplete, hindering the further advancement of the solid oxide cells.Despite the emergence of more advanced materials in recent years, the lanthanum-strontium-manganite La1-xSrxMnO3-δ (LSM) remains to be widely used for an oxygen electrode construction. This preference is due to its cost-effectiveness, high electrical conductivity, thermal and chemical stability, and compatibility with various solid electrolytes. Although LSM has been known for several decades, the reaction mechanism occurring on this oxygen electrode in a broad range of electrode potentials is inadequately described, with discrepancies arising among different authors. These inconsistencies are often linked to the evolving understanding of the non-stationary properties of the LSM lattice – the inner defect chemistry of LSM.Contemporary studies increasingly adopt the concept of ionic conductivity of LSM enabled by cathodic polarization to describe the oxygen reduction reaction. This shift from exclusive electron to ionic-electron conductivity enhances the performance of the LSM electrode, potentially causing discrepancies in the literature as experimental data may not align with theoretical descriptions. Conversely, for the oxygen evolution reaction during anodic polarization, a reversed reaction mechanism is considered without accounting for ionic conductivity of LSM under either stationary or non-stationary conditions. This approach may oversimplify the defect chemistry of LSM, particularly during transitions between operational regimes (i.e., fuel cell and electrolyser regimes). However, such changes are difficult to describe only by experimental approach. Here a combination with mathematical modelling seems to be promising approach allowing to gain deeper understanding.The primary objective of this study is to further investigate the impact of LSM defect chemistry on electrode performance, proposing a reaction scheme during both operating regimes and, crucially, during transitions between them.To address this goal, a series of experiments were conducted under both current-less and current-load conditions using laboratory button single cells. Various gas compositions and operating temperatures were used to determine whether LSM becomes a mixed ionic-electron conductor. Potentiostatic or potentiodynamic methods were used to clarify how this altered property influences individual operating regimes. The results indicate that cathodic polarization leads to a partial reduction of Mn4+ to Mn2+ in the crystalline lattice of LSM, creating oxygen vacancies through which oxide ions can be transported. Additionally, these lattice changes, though temporary, impact the oxygen evolution reaction region under certain conditions. A mathematical model incorporating parallel reaction pathways for both operating regimes supports these experimental results, predicting a cathodic potential at which ionic conductivity becomes viable and identifying conditions where partial reduction of Mn ions is no longer possible.This work contributes to understanding solid oxide cells, providing a solid foundation for more complex mathematical modeling of electrolysis cells. It underscores the necessity to fully comprehend the electrochemical behavior of electrode materials for the continued development of this technology.This work was supported by the Technology Agency of the Czech Republic under project no. TK04030143 (Advanced reversible system for hydrogen production on base of the high temperature solid oxide cell).

Depth filtration of dredged sediments via reduced iron driving persulfate sodium activation: Perspectives from technical viability, potential mechanism, and prospect assessment

The existing single-use conditioning agents for dredged sediments (DS) treatment were confronted with problems such as high cost, insufficient efficiency, or potential toxicity. The study, for the first time, utilized a heterogeneous process of reduced iron (RI)/Persulfate sodium (PS) to deeply filter DS and further uncovered the potential mechanism as well as raised the application prospect. The results showed that after 120 mg/g TSS RI with 40 mg/g TSS PS treatment, the water content (WC) of DS dropped from 75.4% (Blank) to 41.6%, which is obviously lower than that of traditional flocculant-treated DS reported. Mechanistic probe indicated that the strengthened filterability of DS is likely evoked by the sulfate radical (SO4●-)/hydroxyl radical (•OH) with the ferrous/ferric substances generated from RI/PS process. SO4●-/•OH damaged extracellular polymeric substances (EPS) along with their major ingredients and possibly disturbed cellulate physiology of DS, which further promoted the dissociation/liberation of bound-water and strengthened a trend toward fluidization but declined the hydrophilicity and stickiness of DS. Moreover, SO4●-/•OH may evoke the proteins conformation to unfold the hydrophobic spots, promoting the escape of untied water also. By extruding the electric-double layers and lowing the negative charge, Ferrous and/or ferric substances promotes the re-aggregation of disrupted DS particles, which potentially leads to the formation of dense & stable flocs through interaction of ferric substances with carboxyl and hydroxyl functional groups in DS, thus facilitating bound-water removal. The findings here not only deepen our understandings upon mechanisms of heterogeneous AOPs conditioning DS filterability but also offer a promising approach for DS treatment in the fields of solid waste management and water environment remediation.

Evaluating the Kerma coefficients relevant to various water-equivalent materials at different photon energies

To investigate the water equivalency of some solid phantoms, relevant Kerma coefficients were determined through both Monte Carlo (MC) simulation and analytical approaches over a wide range of photon energies ranging from 1 keV to 20 MeV.MCNPX MC Code was employed to simulate the Kerma coefficients for A-150, PMMA, Polystyrene, Solid Water (RMI 457), Solid Phantom (RW3), Virtual water, Solid Water (WT1), and Water Equivalent (Wte) solid phantoms. Kerma coefficients were also theoretically calculated using the mass energy absorption coefficients at different photon energies ranging from 1 keV to 20 MeV. Obtained Kerma coefficients for considered solid phantoms were also compared with those of water to find which material shows the best water-equivalency.Calculated Kerma coefficients by MC simulation were in a good agreement with those calculated via an analytical method which no statistically significant differences were observed among simulated and analytically calculated Kerma coefficients (p-value>0.05). Solid water (RMI 457) showed the best water-equivalency among studied plastic phantoms for radiology and radiotherapy quality assurance purposes. From the results, the Kerma coefficients for solid phantoms are highly dependent on photon energy.

In vitro efficacy of Rosa damascena solid state fermentation liquid and water extract on skin care.

As a medicinal and food homologous plant, Rosa damascena is not only highly ornamental, but also rich in a variety of active ingredients such as polyphenols and flavonoids. It is widely used in cosmetics, food and pharmaceutical industries. To study the in vitro efficacy of Rosa damascena solid state fermentation liquid (RDF) and water extract (RDE). Firstly, the effect of RDF and RDE on the proliferation rate of B16F10 cells was detected by CCK-8 method, and the melanin content was measured by sodium hydroxide lysis method to evaluate the whitening effect of them. Finally, the antioxidant, anti-wrinkling and soothing effects of RDF and RDE were evaluated by biochemical methods in vitro. RDF and RDE within a certain concentration range (0.05%-0.5%) had no effect on the proliferation of B16F10 cells. Compared with Rosa damascena extract (RDE), RDF showed significant effects on bleaching, antioxidant, anti-wrinkling and soothing, among which 0.5% RDF showed the best effect. Both RDF and RDE at a certain concentration have effect on skin care in vitro, but the effect of RDF is more significant than that of RDE.

Validation of Acuros for total body irradiation at extended distance.

Standardized and accurately reported doses are essential in conventional total body irradiation (TBI), especially lung doses. This study evaluates the accuracy of the Acuros algorithm in predicting doses for extended-distance TBI. Measurements and calculations were done with both 6 and 18 MV. Tissue Maximum Ratio (TMR), output and off axis ratios (OAR) were measured at 200 and 500cm source to detector distance and compared to Acuros calculated values. Two end-to-end tests were carried out, one with an in-house phantom (solid water and Styrofoam) with inserted ion chambers and the other was with the Imaging and Radiation Oncology Core (IROC) TBI anthropomorphic phantom equipped with TLDs. The end-to-end test was done for 6 and 18 MV both with and without lung blocks. The source to midplane distance for both phantoms were at 518 and 508cm respectively. Lung blocks were placed at the phantom surface and a beam spoiler was positioned 30cm from the surface of the phantoms as per our clinical set up. The agreement between measured and calculated TMR, output and off axis ratios for both 6 and 18 MV were within 2%. Ion chamber measurements in both the Styrofoam and solid water for both energies carried out with and without lung blocks were within 2% of calculated values. TLD measured doses for both 6 and 18 MV in the IROC phantom were within 5% of calculated doses which is within the uncertainty of the TLD measurement. The results indicate that the clinical beam model for Acuros 16.1 commissioned at standard clinical distances is capable of calculating doses accurately at extended distances up to 500cm.

Preparation and characterization of a nanostructured lipid carrier for phenylethyl resorcinol

Phenylethyl resorcinol (PR) demonstrates inhibitory effects on multiple targets in the melanin synthesis pathway, resulting in a strong whitening effect. However, challenges such as limited solubility in water and susceptibility to oxidation and discoloration restrict its practical application in the cosmetics industry. In order to enhance stability and performance characteristics, a whitening nanostructured lipid carrier (NLC) was synthesized through high-pressure homogenization. This method entailed the incorporation of solid lipids, a liquid lipid, and a compound emulsifier, with deionized water fulfilling the roles of solid phase, liquid phase, and water phase, respectively. The NLC's particle size, Zeta potential, stability, encapsulation efficiency, and other parameters were assessed using techniques such as particle sizer, stability analyzer, and HPLC. The results showed that the NLC for phenylethyl resorcinol prepared by using the optimal formula (7.50 % solid lipids, 3.00 % ethylhexyl palmitate, and 2.00 % Tween 80 and soybean lecithin) has an encapsulation efficiency of 87.11 %, a particle size of 157.2 ± 0.70 nm, a kinetic instability of less than 1.2, and a greatly improved stability, thereby successfully solving the problems of unstable storage and poor solubility of phenylethyl resorcinol.

Design, construction, and dosimetry of 3D printed heterogeneous phantoms for synchrotron brain cancer radiation therapy quality assurance

Objective. This study aims to design, manufacture, and test 3D printed quality assurance (QA) dosimetry phantoms for synchrotron brain cancer radiation therapy at the Australian synchrotron. Approach. Fabricated 3D printed phantoms from simple slab phantoms, a preclinical rat phantom, and an anthropomorphic head phantom were fabricated and characterized. Attenuation measurements of various polymers, ceramics and metals were acquired using synchrotron monochromatic micro-computed tomography (CT) imaging. Polylactic acid plus, VeroClear, Durable resin, and tricalcium phosphate were used in constructing the phantoms. Furthermore, 3D printed bone equivalent materials were compared relative to ICRU bone and hemihydrate plaster. Homogeneous and heterogeneous rat phantoms were designed and fabricated using tissue-equivalent materials. Geometric accuracy, CT imaging, and consistency were considered. Moreover, synchrotron broad-beam x-rays were delivered using a 3 Tesla superconducting multipole wiggler field for four sets of synchrotron radiation beam qualities. Dose measurements were acquired using a PinPoint ionization chamber and compared relative to a water phantom and a RMI457 Solid Water phantom. Experimental depth doses were compared relative to calculated doses using a Geant4 Monte Carlo simulation. Main results. Polylactic acid (PLA+) shows to have a good match with the attenuation coefficient of ICRU water, while both tricalcium phosphate and hydroxyapatite have good attenuation similarity with ICRU bone cortical. PLA+ material can be used as substitute to RMI457 slabs for reference dosimetry with a maximum difference of 1.84%. Percent depth dose measurement also shows that PLA+ has the best match with water and RMI457 within ±2.2% and ±1.6%, respectively. Overall, PLA+ phantoms match with RMI457 phantoms within ±3%. Significance and conclusion. The fabricated phantoms are excellent tissue equivalent equipment for synchrotron radiation dosimetry QA measurement. Both the rat and the anthropomorphic head phantoms are useful in synchrotron brain cancer radiotherapy dosimetry, experiments, and future clinical translation of synchrotron radiotherapy and imaging.

Corrosion behavior of low melting glass modified potassium silicate coating under the synergy of solid NaCl deposit and water vapor at 700 °C

The effects of LMG (SiO2–BaO–Al2O3–TiO2–Na2O–K2O–ZnO) modification on the performance of potassium silicate coatings on Ti–6Al–4V alloy during tests of either H2O/O2- or NaCl/H2O/O2- corrosion were investigated at 700 °C for 500 h using thermogravimetric, SEM, EPMA, and XRD. Adding 10-30 wt% LMG particles into the potassium silicate solution did not impair the intact and the surface roughness of the coatings and improved the resistance of the coatings against humid oxygen corrosion and NaCl/H2O/O2-induced corrosion. For the humid oxygen corrosion, the improvement was enhanced when the amounts of LMG was increased. However, the LMG10 coating with 30 vol% LMG had the most excellent corrosion resistance, the formation of titanate was prohibited; the coatings with more LMG additions were less protective than LMG10 though better than the coating without LMG.

Near-infrared Spectroscopy for Remote Sensing of Porosity, Density, and Cubicity of Crystalline and Amorphous H2O Ices in Astrophysical Environments

We present laboratory spectra of pure amorphous and crystalline H2O ices in the near-infrared (NIR, 1–2.5 μm/10,000–4000 cm−1) at 80–180 K. The aim of this study is to provide spectroscopic reference data that allow remotely accessing ice properties for icy objects such as icy moons, cometary ice, or Saturn rings. Specifically, we identify new spectral markers for assessing three important properties of ices in space: (i) porosity/fluffiness, (ii) bulk density of amorphous ice, and (iii) cubicity in crystalline ice. The analysis is based on the first OH-stretching overtone (2ν OH) and the combinational band at 5000 cm−1/2 μm, which are potent spectral markers for these properties. By comparison of vapor-deposited, microporous amorphous solid water, pore-free low-, high-, and very-high-density amorphous ice, we are able to separate the effect of (bulk) density from the effect of porosity on NIR-spectra of amorphous ices. This allows for clarifying a longstanding inconsistency about the density of amorphous ice vapor-deposited at low temperatures, first brought up by Jenniskens & Blake. Direct comparison of NIR spectra with powder X-ray diffractograms allows us to correlate spectral features with the number of cubic stacking layers in stacking-disordered ice Isd, ranging from fully cubic ice Ic to fully hexagonal ice Ih. We show that exposure times for instruments on the James Webb Space Telescope are in the hour range to distinguish these properties, demonstrating the usefulness of the neglected NIR spectral range for identifying ices in space.

Utilizing Microbial Fuel Cells For Simultaneous Treatment Of Solid Waste Water And Energy Generation

The proposed biocatalyst utilized in the microbial fuel cell (MFC) experiment demonstrated exo-electrogenic activity, with species such as Mycobacterium and Shewanella (Pseudomonas) sourced from sewer wastewater. Chemical parameters from the initial experimental trial did not comply with Environmental Protection Agency (EPA) limits. The total suspended solids (TSS) in the second MFC trial were the only parameter to meet the EPA threshold of 50 ppm, with influent and effluent concentrations of 96 ppm and 23.1 ppm, respectively. Consequently, supplementary treatment methods are required to achieve EPA discharge standards. The second trial indicated that the MFC setup effectively reduced metal concentrations, including Cr, Mn, Pb, and Zn, to levels that satisfy EPA surface water effluent discharge criteria. Keywords: microbial fuel cell, anode chamber, cathode chamber, wastewater, energy generation. Aims Research Journal Reference Format: Adeniyi O. A., Bakri A.J., Samuel O. Fadipe, Shakirat B. A., Adebayo O.C. & Oyetunde R.A. (2024): Utilizing Microbial Fuel Cells For Simultaneous Treatment Of Solid Waste Water And Energy Generationelta. Advances in Multidisciplinary and Scientific Research Journal Vol. 10. No. 2. Pp 55-69. www.isteams.net/aimsjournal. dx.doi.org/10.22624/AIMS/V10N2P6

Development of a new reagent for the prevention of asphaltene-resin-paraffin deposits

Asphaltene-Resin-Paraffin deposits (ARPD) form a certain proportion of the crude oil mass, separating as temperature and pressure decrease and adsorbing to the surfaces of the reservoir wellbore zone, downhole equipment and tubulars. These deposits precipitate in the wellbore zone, oilfield equipment and pipes,resulting in reduced system productivity, reduced pumping efficiency of the pumping equipment and other negative consequences. Asphalt-resin and paraffin deposits (ARPD) are a complex mixture of solid paraffin hydrocarbons, asphalt-resin substances (ARS), water and mechanical impurities. The strength and composition of ARPD depend on the composition and properties of oil, geological, physical and technological conditions of field development. Chemical methods for removing deposits are currently the most widely used, as they are highly effective and technologically advanced. To this end, new reagents have been developed and their physico-chemical properties have been studied. Subsequently, the selected reagents were tested on oil samples from Oil and Gas Production Department (OGPD) with a paraffin content of more than 6 %. It was also shown that paraffin inhibitors have individual effects; a reagent that is effective on oil from one field may not have the same effect on oil from other fields. The research includes studies of selected reagents for paraffinic oils from different fields. Using the «cold finger» method, the efficacy of the selected reagents against paraffin deposition was investigated and their optimum doses were determined. Keywords: reagent; sendiment; paraffin; asphaltene; resin; well bottom zone; viscosity; depressor.

Mapping Stakeholders in the Development of Eco-Cities: Insights from Nepal and Indonesia

Urban areas are dynamic and intricate, encompassing various social, economic, ecological, and cultural aspects. It's crucial to employ effective approaches and management methods to achieve sustainable urban development. Stakeholder analysis is pivotal in understanding their roles and responsibilities in this process. By analyzing potential stakeholders and their responsibilities, enhances achieving development goals. This paper uses ‘solid waste bank’ and ‘socio-cultural water management approach’ case of Surabaya, Indonesia and Lalitpur, Nepal respectively. The challenges stakeholders face when implementing have been studied and mapped. Additionally, the significance of stakeholders in implementing development plans and policies has been reviewed through relevant journals and reports, considering the current cases of solid waste management and water management only. The mapping of stakeholders’ problems and prospects revealed that none of the stakeholders had low influence and low importance in both Nepal and Indonesia. This finding suggests that further studies could explore other relevant aspects of the stakeholder dynamics that could contribute to developing eco-city in both the countries. Also mapping, synthesizing both situation and stakeholder of other practices, and upgrading the practices as well may help achieve eco-city, which is unique, inclusive and has the contextual flavors.

Radiochromic film EBT3 calibration for linear accelerator in 10 MV

Radiochromic film is used to applications in dosimetry have become increasingly significant for studies on radiotherapy. Due to sensitivity to exposure to ionizing radiation, radiochromic films are commonly used to obtain dose distribution maps and for calibration curves. The calibration curves in the radiochromic films can be use radiochromic films as a dosimetry method and then seek the generation of images with lower dose deposition and higher diagnostic quality. When ionizing radiation interacts with matter it generates energy deposition. Radiation dosimetry is important for medical applications of ionizing radiation due to the increasing demand for diagnostic radiology and radiotherapy. The film is a dose measurement method that records the energy deposition by the darkening of its emulsion. Radiochromic films have a little visible light sensitivity and respond better to ionizing radiation exposure. The aim of this study is to obtain the resulting calibration curve by the irradiation of radiochromic film strips, making it possible to relate the darkening of the film with the absorbed dose, to measure doses in experiments with X-ray beam of 10 MeV in Linear Accelerator. The objective of this study is to obtain the calibration curves of the radiographic film for exposure with X-ray beam in Linear Accelerator scanner for realize measures of typical doses found in radiotherapy. It was used Gafchromic EBT Radiochromic Film, which shows little sensitivity to visible light and a response in the range of 0.1 to 10 Gy for X-ray beam. In the experiments, a Solid Water Phantom, with a 30x30x2.0 cm³. The strips were scanned and processed using the ImageJ software to obtain the intensity values resulting from the absorbed radiation by grayscale. The darkening responses on film strips according to the doses were observed and they allowed obtaining the corresponding numeric values to the darkening for each specific dose value. From the numerical values of darkening, a calibration curve was obtained.

A Comparison Study of the Solid Phantom and Water Phantom Using 6 MV and 15 MV Photon Energies, Depending on the Depth

Water is such an environmental element that is considered the best human body tissue equivalent. In the field of dosimetry studies, water is frequently used. This comparison study is conducted by a solid phantom and a water phantom with 6 MV and 15 MV photon energies, respectively. A cylindrical-type ionization chamber is used to collect charge when beams are on. The distance between the ray source and the surface of the phantom was fixed at 100 cm i.e. to SSD (Source to Surface Distance) of during the experiment. Chamber travels 1 cm to 20 cm in both phantoms and an electrometer is attached in the experimental set-up to measure the charge. The field size was 10x10 cm2. The relative deviation ratio of the solid phantom to the water phantom was calculated. In the result, the maximum deviation was 0.64%, while the minimum deviation was 0%, corresponding to the depths of 1 cm and 2.5 cm, respectively, for 6 MV and at 15 MV, maximum deviation and minimum deviation were 1.90% and 0.167% respectively, corresponding to the depths of 1.5 cm and 13 cm. Therefore, it can be said that the solid phantom can overcome the disadvantages of installation time required for the water phantom and problems while water level changing for depth measurement, simultaneously can used to measure the radiological dose precisely. Bangladesh J. Nuclear Med. 27(1): 34-38, 2024

Enhancement of mechanical properties, durability and service life of low carbon cement paste with super low w/c ratio by incorporating carbon fiber

The high strength and durability of cement-based materials are pivotal for energy conservation and carbon emission reduction. By employing solid water mixing technology, a cement-based material with a significantly high compressive strength was developed. However, the concurrent increase in brittleness prompted the exploration of carbon fiber as a potential bridging agent to improve toughness. This paper investigates the role of carbon fiber reinforcement in enhancing the mechanical properties, durability, and service life of cement paste with a super low water-to-cement (w/c) ratio. The results demonstrated that the addition of 0.3 vol% carbon fiber led to an 18.4 % increase in 28-day flexural strength compared to the control group, as well as a 15.3 % increase in flexural compression ratio. Furthermore, under the same carbon fiber content, the drying shrinkage rate after 150-day exhibited a decrease of 20.3 %, and there was a notable decrease of 35.80 % in compressive strength loss rate after 200 freezing-thawing cycles. Service life was significantly improved. It showed that carbon fiber could improve the toughness and durability of hardened cement paste.

Evaluation of cutout factors with small and narrow fields using various dosimetry detectors in electron beam keloid radiotherapy.

The inherent problems in the existence of electron equilibrium and steep dose fall-off pose difficulties for small- and narrow-field dosimetry. To investigate the cutout factors for keloid electron radiotherapy using various dosimetry detectors for small and narrow fields. The measurements were performed in a solid water phantom with nine different cutout shapes. Five dosimetry detectors were used in the study: pinpoint 3D ionization chamber, Farmer chamber, semiflex chamber, Classic Markus parallel plate chamber, and EBT3 film. The results demonstrated good agreement between the semiflex and pinpoint chambers. Furthermore, there was no difference between the Farmer and pinpoint chambers for large cutouts. For the EBT3 film, half of the cases had differences greater than 1%, and the maximum discrepancy compared with the reference chamber was greater than 2% for the narrow field. The parallel plate, semiflex chamber and EBT3 film are suitable dosimeters that are comparable with pinpoint 3D chambers in small and narrow electron fields. Notably, a semiflex chamber could be an alternative option to a pinpoint 3D chamber for cutout widths≥3 cm. It is very important to perform patient-specific cutout factor calibration with an appropriate dosimeter for keloid radiotherapy.

Skin dose investigations on a 0.5 T parallel rotating biplanar linac-MR using Monte Carlo simulations and measurements.

The Alberta rotating biplanar linac-MR has a 0.5 T magnetic field parallel to the beamline. When developing a new linac-MR system, interactions of charged particles with the magnetic field necessitate careful consideration of skin dose and tissue interface effects. To investigate the effect of the magnetic field on skin dose using measurements and Monte Carlo (MC) simulations. We develop an MC model of our linac-MR, which we validate by comparison with ion chamber measurements in a water tank. Additionally, MC simulation results are compared with radiochromic film surface dose measurements on solid water. Variations in surface dose as a function of field size are measured using a parallel plate ion chamber in solid water. Using an anthropomorphic computational phantom with a 2mm-thick skin layer, we investigate dose distributions resulting from three beam arrangements. Magnetic field on and off scenarios are considered for all measurements and simulations. For a 20×20cm2 field size, (the minimum dose to the hottest contiguous 0.2 cc volume) for the top 2mm of a simple water phantom is 72% when the magnetic field is on, compared to 34% with magnetic field off (values are normalized to the central axis dose maximum). Parallel plate ion chamber measurements demonstrate that the relative increase in surface dose due to the magnetic field decreases with increasing field size. For the anthropomorphic phantom, (minimum skin dose in the hottest 1×1×1 cm3 cube) shows relative increases of 20%-28% when the magnetic field is on compared to when it is off. With magnetic field off, skin is 71%, 56%, and 21% for medial-lateral tangents, anterior-posterior beams, and a five-field arrangement, respectively. For magnetic field on, the corresponding skin values are 91%, 67%, and 25%. Using a validated MC model of our linac-MR, surface doses are calculated in various scenarios. MC-calculated skin dose varies depending on field sizes, obliquity, and the number of beams. In general, the parallel linac-MR arrangement results in skin dose enhancement due to charged particles spiraling along magnetic field lines, which impedes lateral motion away from the central axis. Nonetheless, considering the results presented herein, treatment plans can be designed to minimize skin dose by, for example, avoiding oblique beams and using a larger number of fields.