Types Of Chambers Research Articles

Validation of MCNPX Calculational Model for Kartini Reactor Outer Core Neutron Flux

Abstract Kartini reactor in Yogyakarta is a nuclear reactor with a low thermal power of 100 kW that is mainly used for education, training, and research. For that purpose, measuring neutron flux and controlling the power are important operational parameters. The Fission Chamber (FC) type of detector is the main component in the reactor operation and safety system that measures the neutron flux in the outer reactor core. As the FC detector is placed in a fixed location, a numerical calculation model is needed to know the neutron flux in all outer core regions. In this study, the MCNPX code is used. The first step is to validate the model with experimental measurement. The objective of the present study is to obtain a validated model by comparing calculations using MCNPX with measurements using gold foil activation (Neutron Activation Analysis technique). The computational model tested showed promising results with an average difference compared to the gold foil activation method of about 23%. Further research can be done using more gold foil samples or foils from other materials to see the consistency of measurements or minimize the measurement difference.

Paleoenvironmental conditions across the Coniacian-Santonian in the Kometan Formation, northeastern Iraq: Insights from planktonic foraminifera distribution, mineralogy and geochemistry

The paleoenvironmental conditions during the Coniacian-Santonian interval within the Kometan Formation in northeastern Iraq have been analyzed through the distribution of depth-related planktonic foraminifera in the carbonate rocks (limestone and marly limestone) of the Kometan Formation using standard washing method for soft samples and thin section method for hard samples supported by mineralogical investigations, geochemical analysis and stable isotopic δ13C and δ18O data. The findings indicate that saline marine waters and a hot, dry to semi-arid climate with low to medium oxygen conditions were conducive to deposition, which was characterized by high organic productivity due to marine transgression. The study revealed that the distribution of shallow water forms (SWF) of globular-shaped foraminifera, compared to deep water forms (DWF) of keeled-shaped genera, along with δ13C data from the late Turonian-early Campanian succession, indicated a relatively low sea level throughout the Late Turonian period. The water level began to rise in the early Coniacian, continuing gradually until the late Coniacian, when a noticeable increase in sea level was observed. This elevated sea level persisted through the early and late Santonian periods, before starting to drop. A slight marine transgression was noted at the beginning of the early Campanian period, followed by a significant drop in sea level. During the late Turonian, a subtropical climate prevailed. Temperature increased during the early to middle Coniacian, decreased slightly at the beginning of the late Coniacian, and then rose again at the end of the late Coniacian, indicating a shift from tropical to subtropical climatic conditions. Similar hot climatic conditions persisted in a tropical-subtropical climate during the early to late Santonian and early Campanian, with a relative temperature drop near the end of the early Campanian. No evidence of an oceanic anoxic event (OAE3) was found in the Kometan Formation during the late Coniacian–early Santonian period. The hypothesized event, based on biostratigraphy, facies analysis, stable isotopes, geochemical evidence, and field study, was limited to demonstrating an increase in the ratio of keeled chamber planktonic foraminifera compared to globular chamber ones. This ratio increase of the keeled chamber types is believed to result from a deepening sedimentary environment due to rising sea levels, creating organic matter-rich beds with high productivity and relatively low oxygen conditions during the Coniacian-Santonian boundary.

Development of novel ionization chambers for reference dosimetry in electron flash radiotherapy

AbstractBackgroundReference dosimetry in ultra‐high dose rate (UHDR) beamlines is significantly hindered by limitations in conventional ionization chamber design. In particular, conventional chambers suffer from severe charge collection efficiency (CCE) degradation in high dose per pulse (DPP) beams.PurposeThe aim of this study was to optimize the design and performance of parallel plate ion chambers for use in UHDR dosimetry applications, and evaluate their potential as reference class chambers for calibration purposes. Three chamber designs were produced to determine the influence of the ion chamber response on electrode separation, field strength, and collection volume on the ion chamber response under UHDR and ultra‐high dose per pulse (UHDPP) conditions.MethodsThree chambers were designed and produced: the A11‐VAR (0.2–1.0 mm electrode gap, 20 mm diameter collector), the A11‐TPP (0.3 mm electrode gap, 20 mm diameter collector), and the A30 (0.3 mm electrode gap, 5.4 mm diameter collector). The chambers underwent full characterization using an UHDR 9 MeV electron beam with individually varied beam parameters of pulse repetition frequency (PRF, 10–120 Hz), pulse width (PW, 0.5–4 µs), and pulse amplitude (0.01–9 Gy/pulse). The response of the ion chambers was evaluated as a function of the DPP, PRF, PW, dose rate, electric field strength, and electrode gap.ResultsThe chamber response was found to be dependent on DPP and PW, and these dependencies were mitigated with larger electric field strengths and smaller electrode spacing. At a constant electric field strength, we measured a larger CCE as a function of DPP for ion chambers with a smaller electrode gap in the A11‐VAR. For ion chambers with identical electrode gap (A11‐TPP and A30), higher electric field strengths were found to yield better CCE at higher DPP. A PW dependence was observed at low electric field strengths (500 V/mm) for DPP values ranging from 1 to 5 Gy at PWs ranging from 0.5 to 4 µs, but at electric field strengths of 1000 V/mm and higher, these effects become negligible.ConclusionThis study confirmed that the CCE of ion chambers depends strongly on the electrode spacing and the electric field strength, and also on the DPP and the PW of the UHDR beam. A significant finding of this study is that although chamber performance does depend on PW, the effect on the CCE becomes negligible with reduced electrode spacing and increased electric field. A CCE of ≥95% was achieved for DPPs of up to 5 Gy with no observable dependence on PW using the A30 chamber, while still achieving an acceptable performance in conventional dose rate beams, opening up the possibility for this type of chamber to be used as a reference class chamber for calibration purposes of electron FLASH beamlines.

Study on radiation heat transfer characteristics of aeroengine combustion chamber

The thermal radiation of gaseous combustion products in an aero-engine combustion chamber has obvious non-ash-body characteristics. In this paper, based on the OpenFOAM platform, a numerical study on multi-field coupled turbulence-combustion-radiation radiative heat transfer was carried out for a certain type of aero-engine combustion chamber using the mean weighted sum of grey gas (WSGG) gas radiation model, which can accurately describe the non-ash characteristics of the gas. The results show that the radiation heat transfer characteristics are influenced by several factors such as equivalent ratio, combustion pressure and wall emissivity, among which the equivalent ratio is dominant. Increasing the equivalence ratio from 0.11 to 0.4 resulted in a 189% increase in average incident radiation at the combustion chamber wall and a 233% increase in average incident radiation at the exit. Increasing the equivalent ratio, combustion pressure or wall emissivity will increase the average radiation intensity in the combustion chamber and the inhomogeneity of radiation distribution at the exit of the combustion chamber. The radial radiation distribution factor (RRDF) also increases with the increase of equivalent ratio, combustion pressure and wall emissivity.

Hyperbaric oxygen (HBO2) therapy in thermal burn injury revisited. Pressure does matter. Review.

ABSTRACT Smolle C, Auinger D, Lindenmann J, Smolle J, Smolle-Juettner FM, Kamolz LP. Hyperbaric oxygen (HBO2) therapy in thermal burn injury revisited. Pressure does matter. Review. Undersea Hyperb Med. 2024 Second Quarter; 51(2):115-127. For over five decades, many experimental and clinical studies have shown predominantly positive but controversial results on the efficacy of hyperbaric oxygen (HBO2) therapy in burns. The study aimed to define a common denominator or constellations, respectively, linked to the effects of HBO2 in burns with a special focus on dosage parameters. Based on original work since 1965, species, number of individuals, type of study, percentage of total body surface area (TBSA), region, depth of burn, causative agent, interval between burn and first HBO2 session, pressure, duration of individual session, number of HBO2 sessions per day, cumulative number of HBO2 sessions and type of chamber were assessed. Out of 47 publications included, 32 were animal trials, four were trials in human volunteers, and 11 were clinical studies. They contained 94 experiments whose features were processed for statistical evaluation. 64 (67.4%) showed a positive outcome, 16 (17.9%) an ambiguous one, and 14 (14.7%) a negative outcome. The only factor independently influencing the results was pressure with ATA (atmospheres absolute) lower than 3 ATA being significantly associated with better outcomes (p=0.0005). There is a dire need for well-designed clinical studies in burn centers equipped with hyperbaric facilities to establish dedicated treatment protocols.

Investigation of ionization chamber-specific beam quality correction factor (kQ,Q0) used for absorbed dose determination in megavoltage photon beams

In the recent past (Andreo et al., 2020), new ionization chamber-specific beam quality correction factors (kQ,Q0) were published in the literature for the determination of the absorbed dose to water in high energy radiotherapy photon beams. In a previous experimental investigation, made at our laboratory, five various Farmer-type cylindrical ionization chambers, i.e. Exradin A12, IBA FC65-G, NE-2571, PTW 30011 and PTW 30012, were studied to examine their responses with reference to the determination of the absorbed dose to water in an inter-chamber comparison. In the present work, measurements were made to experimentally study the relation or ratio of the kQ,Q0 correction factors using the five various types of the ionization chambers employed in our previous investigation. In total, nine ionization chambers, two of each type, were included in the present study, with the exception of a single PTW 30011 ionization chamber. The photon beams employed were the 6 MV and the 15 MV beam. The outcomes of this work displayed excellent agreement between the ratio of the ionization chamber-specific kQ,Q0 correction factors, for the ionization chambers utilized, and the corresponding ratio calculated using the published kQ,Q0 correction factors. The discrepancy obtained in these comparisons was within 0.1%, for both the photon beams examined, which is much smaller than the uncertainty associated with the determination of this relationship.

The development of patient-specific quality assurance (PSQA) for a proton wobbling nozzle using PTSim Monte Carlo code

The aim of this study is to develop a Monte Carlo-based platform for patient-specific quality assurance (PSQA) in the proton wobbling nozzle at Chang Gung Memorial Hospital. To efficiently reduce time usage and enhance simulated precision, this platform required an initial fine-tuning of the Guard volume (GV) and lateral displacement (LD) settings. Different GV sizes combined with LD modes were utilized to estimate depth dose profiles in a water phantom. The simulated central axis depth doses were then analyzed using PTSim and compared to measurement using a PTW MP3 water tank and a Markus ionization chamber type 34045. Treatment parameters for a liver case were extracted from the Eclipse DICOM RT Plan file. Simulated doses were compared to measurements using Zebra and MatriXX systems during PSQA process. Furthermore, a geometrical trigger technique was applied to assess the track positions in patient-specific components. The study found that the mean dose difference between measured and simulated values for the optimized LD/GV was below 1% at all depth positions. With passing rates of 97.4% at the middle SOBP and 90.3% at the proximal SOBP, the gamma analysis demonstrated satisfactory results. For the axial dose profile, SOBP flatness was within 2.5%. From the geometric trigger analysis, more than 95–98% of the dose was delivered through the range compensator, while approximately 2–5% originated from scattered protons from the Multi-Leaf Collimator (MLC) and block's edges. The PTSim simulation's performance in conducting PSQA demonstrated its capability and reliability.

Hyperbaric oxygenation helps you live comfortably history of hyperbaric oxygenation

The article highlights historical aspects and conducts a retrospective analysis of the use of hyperbaric oxygenation, presents types of pressure chambers, pays attention to the use of hyperbaric oxygenation, analyzes the method, preparation and conduct of a hyperbaric oxygenation session.

Experimental comparison of cylindrical and plane parallel ionization chambers for reference dosimetry in continuous and pulsed scanned proton beams

Objective. In this experimental work we compared the determination of absorbed dose to water using four ionization chambers (ICs), a PTW-34045 Advanced Markus, a PTW-34001 Roos, an IBA-PPC05 and a PTW-30012 Farmer, irradiated under the same conditions in one continuous- and in two pulsed-scanned proton beams. Approach. The ICs were positioned at 2 cm depth in a water phantom in four square-field single-energy scanned-proton beams with nominal energies between 80 and 220 MeV and in the middle of 10 × 10 × 10 cm3 dose cubes centered at 10 cm or 12.5 cm depth in water. The water-equivalent thickness (WET) of the entrance window and the effective point of measurement was considered when positioning the plane parallel (PP) ICs and the cylindrical ICs, respectively. To reduce uncertainties, all ICs were calibrated at the same primary standards laboratory. We used the beam quality (k Q ) correction factors for the ICs under investigation from IAEA TRS-398, the newly calculated Monte Carlo (MC) values and the anticipated IAEA TRS-398 updated recommendations. Main results. Dose differences among the four ICs ranged between 1.5% and 3.7% using both the TRS-398 and the newly recommended k Q values. The spread among the chambers is reduced with the newly k Q values. The largest differences were observed between the rest of the ICs and the IBA-PPC05 IC, obtaining lower dose with the IBA-PPC05. Significance. We provide experimental data comparing different types of chambers in different proton beam qualities. The observed dose differences between the ICs appear to be related to inconsistencies in the determination of the k Q values. For PP ICs, MC studies account for the physical thickness of the entrance window rather than the WET. The additional energy loss that the wall material invokes is not negligible for the IBA-PPC05 and might partially explain the low k Q values determined for this IC. To resolve this inconsistency and to benchmark MC values, k Q values measured using calorimetry are needed.

경남내륙지역 목관·목곽묘의 구조적 특징과 축조양상

This study examined the wooden gasket tombs and wooden chamber tombs in Gyeongnam Inland areas from two main perspectives. It summarizes recent excavation cases to review the structural characteristics of these tombs and infers the construction style and burial methods through the example of the Jeongjang-ri Tomb No. Ⅲ-86. Firstly, the wooden gasket tombs consist of ① burial area (tomb pit), ② wooden gasket, ③ backfill soil, ④ topsoil, ⑤ wooden fence, and ⑥ mound, which are not significantly different from those found in the Yeongnam region. However, the wooden gasket tomb at Jangchon-ri B-25 is a unique half-cut chamber type. What is particularly noteworthy is that the lower part of the tomb pit is excavated about 10° eastward from the top, where the wooden gasket is placed. Additionally, the wooden gasket tomb at Dohang-ri #48 lacks backfill soil and exhibits a distinctive structure with retaining walls. The structure of the wooden chamber tombs consists of ① burial area (tomb pit), ② wooden chamber, ② wooden gasket, ③ pedestal, ④ backfill soil, ⑤ topsoil, ⑥ capstone, and ⑦ outer wall. There are various types of wooden chamber tombs, including single-chamber style, double-chamber style, and compound chamber style. Among them, the wooden chamber tombs in Jeongjang-ri is notably distinct because it has separate compartments on both walls for the relics among the double-chamber style tombs that have both the inner and outer walls and the single-chamber style tombs. Additionally, the floor surface is excavated to install a pedestal, and two to five wooden planks are placed across it. And it is clear that the inside and outside are installed on the wooden board. Second, the architectural features and burial styles have been reconstructed by inferring the procedure of construction based on the structural features of the Jeongjang-ri Tomb No. Ⅲ-86. The assumed procedure is as follows: Excavation of the ① burial area and ② tomb pit and installation of the pedestal → Installation of horizontal wooden planks and longitudinal planks → ④ Installation of inner and outer walls and backfilling → ⑤ Placement of body and artifacts → ⑥ Closing and sealing of the wooden gasket and mound construction. Therefore, the Jeongjang-ri Tomb No. Ⅲ-86, among others, holds significance as it provides an opportunity to comprehensively reconstruct the structural characteristics and construction processes of wooden chamber tombs in the Gyeongnam Inland region.

Fano cavity test and investigation of the response of the Roos chamber irradiated by proton beams in perpendicular magnetic fields up to 1 T

Objective. The aim of this work is to investigate the response of the Roos chamber (type 34001) irradiated by clinical proton beams in magnetic fields. Approach. At first, a Fano test was implemented in Monte Carlo software package GATE version 9.2 (based on Geant4 version 11.0.2) using a cylindrical slab geometry in a magnetic field up to 1 T. In accordance to an experimental setup (Fuchs et al ), the magnetic field correction factors kQB⃗ of the Roos chamber were determined at different energies up to 252 MeV and magnetic field strengths up to 1 T, by separately simulating the ratios of chamber signals MQ/MQB⃗, without and with magnetic field, and the dose-conversion factors Dw,QB⃗/Dw,Q in a small cylinder of water, with and without magnetic field. Additionally, detailed simulations were carried out to understand the observed magnetic field dependence. Main results. The Fano test was passed with deviations smaller than 0.25% between 0 and 1 T. The ratios of the chamber signals show both energy and magnetic field dependence. The maximum deviation of the dose-conversion factors from unity of 0.22% was observed at the lowest investigated proton energy of 97.4 MeV and B⃗ = 1 T. The resulting kQB⃗ factors increase initially with the applied magnetic field and decrease again after reaching a maximum at around 0.5 T; except for the lowest 97.4 MeV beam that show no observable magnetic field dependence. The deviation from unity of the factors is also larger for higher proton energies, where the maximum lies at 1.0035(5), 1.0054(7) and 1.0069(7) for initial energies of E0 = 152, 223.4 and 252 MeV, respectively. Significance. Detailed Monte Carlo studies showed that the observed effect can be mainly attributed to the differences in the transport of electrons produced both outside and inside of the air cavity in the presence of a magnetic field.

Hyperbaric oxygen treatment for infants: retrospective analysis of 54 patients treated in two tertiary care centres.

We aimed to analyse the outcomes of hyperbaric oxygen treatment (HBOT) and describe difficulties encountered in infants, a rare patient population in this therapeutic intervention, with limited scientific reports. This was a retrospective analysis of patients 12 months old or younger who underwent HBOT in two different institutions. Demographic data, clinical presentation, HBOT indication, chamber type, oxygen delivery method, total number of treatments, outcome and complications were extracted from clinical records. There were 54 infants in our study. The patients' median age was 3.5 (range 0-12) months. The major HBOT indication was acute carbon monoxide intoxication (n = 32). A total of 275 HBOT treatments were administered, mostly performed in multiplace chambers (n = 196, 71%). Only one patient (2%) required mechanical ventilation. Acute signs were fully resolved in the most patients (n = 40, 74%). No complications related to HBOT were reported. This study suggests that HBOT may be a safe and effective treatment for infants. Paediatricians should consider HBOT when indicated in infants even for the preterm age group.

Analysis of Fluid Replacement in Two Fluidic Chambers for Oblique-Incidence Reflectivity Difference (OI-RD) Biosensor.

Optical biosensors have a significant impact on various aspects of our lives. In many applications of optical biosensors, fluidic chambers play a crucial role in facilitating controlled fluid delivery. It is essential to achieve complete liquid replacement in order to obtain accurate and reliable results. However, the configurations of fluidic chambers vary across different optical biosensors, resulting in diverse fluidic volumes and flow rates, and there are no standardized guidelines for liquid replacement. In this paper, we utilize COMSOL Multiphysics, a finite element analysis software, to investigate the optimal fluid volume required for two types of fluidic chambers in the context of the oblique-incidence reflectivity difference (OI-RD) biosensor. We found that the depth of the fluidic chamber is the most crucial factor influencing the required liquid volume, with the volume being a quadratic function of the depth. Additionally, the required fluid volume is also influenced by the positions on the substrate surface bearing samples, while the flow rate has no impact on the fluid volume.

Magnetic field configuration effects on a miniature DC ion thruster with an inverted potential structure

To improve the mass utilization and total efficiency of miniature direct current (DC) ion thrusters, this article proposes a graphene–oxide–semiconductor (GOS) electron source as a cathode in the discharge chamber and neutralizer. To apply the GOS device to the discharge chamber, multiple electron sources were positioned downstream to provide sufficient electrons for plasma generation. Accordingly, the anode was placed upstream of the discharge chamber; thus, the potential structure was inverted from that of a conventional device. Based on this concept, two discharge chamber types were developed with different magnetic field configurations (1- and 2-Cusp types) using a filament cathode and their performance was experimentally evaluated. Probe diagnostics results showed that plasma was generated mainly in the center of the discharge chamber in 1-Cusp, whereas it was generated in the entire discharge chamber in 2-Cusp. Regarding ion beam extraction with 211-hole grids, 1-Cusp exhibited a higher screen current than 2-Cusp. However, using 391-hole grids with an expanded ion-extraction region, 2-Cusp outperformed 1-Cusp with 211-hole grids, attaining a minimum discharge loss of 273 W/A (excluding filament power) and a maximum mass utilization efficiency of 0.48.

Reply to “Comment on Comparison of direct and indirect measures of transport efficiency in single particle inductively coupled plasma mass spectrometry” by H. Goenaga-Infante

This paper provides a rebuttal to the comments on our original research article entitled “Comparison of Direct and Indirect Measures of Transport Efficiency in Single Particle ICP-MS” recently published by Goenaga-Infante in Spectrochimica Acta Part B: Atomic Spectroscopy.The intent of our study is not to condemn the dynamic mass flow (DMF) method but rather to explore the use parameters under which it can and cannot be applied. As explained in the original paper, the goal of this study is to evaluate the ranges of use conditions under which measures of transport efficiency (TE) yield accurate and reproducible results for spICP-MS measurements of particle number concentration (PNC) and particle size (diameter, PS) of various gold nanoparticle (AuNP) suspensions. The evaluation was performed through a systematic comparison of three methods for the measurement of TE: the particle frequency (TEF), particle size (TES), and DMF methods using three types of spray chambers operated at cooled and ambient temperature conditions and employing different ICP-MS platforms. While we appreciate thorough critical and constructive comments on our paper, we strongly disagree that the conclusions and highlights are not supported by the content and findings about the features and benefits of the DMF method.The discussion of three additional independent studies in this field by other spICP-MS expert groups that have been published after the submission of our manuscript is included in this paper. While the DMF approach has been used in two interlaboratory comparisons for TE determination in spICP-MS measurements of PNC, only one laboratory, namely the laboratory led by Goenaga-Infante, provided results using the DMF method in both projects. A method cannot be considered validated if successful results have only been demonstrated within one laboratory.The paper by Goenaga-Infante claims that the main use of DMF, the assignment of a SI traceable PNC value to new commercial nanomaterials (NMs), has not been highlighted explicitly in our original paper. The advantages and disadvantages of the DMF, TES, and TEF methods to measure TE were presented throughout the manuscript and are clearly summarized in the conclusion. The assignment of PNC that is metrologically traceable to the SI implies that all known or suspected uncertainty components including bias are taken into account. Our research shows that under some use conditions, the biases inherent to the DMF method are not yet fully understood and cannot be accounted for. While Cuello-Nuñez et al. Journal of Analytical Atomic Spectrometry, 2020, DOI: https://doi.org/10.1039/c9ja00415g state that cooled conditions (2 °C) were used in their work, they do not define the level of bias that can be expected if different spray chamber temperatures are used, and they do not provide recommendations on the optimal use conditions that define the field of applicability of the DMF method. Furthermore, besides the use of a Scott-type spray chamber cooled to 2 °C, neither the composition material of the spray chamber nor the volume of the Scott-type spray chamber were specified. It is important to note that in our original research, fifteen of the nineteen experiments were conducted using a cooled spray chamber. Also, the four different ICP-MS platforms were used in the standard configuration and with additional spray chamber options encountered in common ICP-MS usage. The value of our work is that it extends the study of Cuello-Nuñez et al. to a wide variety of use conditions routinely encountered in spICP-MS analysis.

Batrachochytrium salamandrivorans is necronotic: carcasses could play a role in Bsal transmission

IntroductionBatrachochytrium salamandrivorans (Bsal) poses a major threat to global amphibian biodiversity. It is essential we understand Bsal transmission to develop better-informed management strategies. Infected carcasses are an important source of transmission for several human and wildlife disease systems; however, they have not been examined as sources for Bsal exposure. Here, we evaluated whether infected newt carcasses could contribute to Bsal transmission dynamics.MethodsWe cohoused infected carcasses with susceptible newts in two cohousing chamber types (partitioned or non-partitioned) at three timepoints post-mortem ([0,24[, [24,48, [48,72] hrs). The partitioned chamber prevented newt-to-newt contact hence only allowed indirect, waterborne transmission of zoospores. We measured shedding rates of infected carcasses at each post-mortem timepoint and monitored infection status and mortality of susceptible newts which were exposed during cohousing events.ResultsOur results indicate carcasses are capable of transmitting Bsal to susceptible newts up to at least 72 hrs post-mortem, even without live newts directly contacting carcasses. All susceptible newts in each chamber type and post-mortem period became infected and >90% experienced disease-induced mortality. Bsal genomic copies/uL in skin swabs taken from infected carcasses were high, averaging 7.4x105, 8.6x105, and 2.0x106 at 24, 48, and 72 hrs post-mortem, respectively. Water samples collected from cohousing chambers averaged 2743 Bsal genomic copies/uL (approximately 1357 zoospores) and did not decline over 72 hrs. DiscussionOur results indicate Bsal infection can occur rapidly between infected carcasses and susceptible aquatic salamanders via indirect and direct transmission pathways, and carcasses may prolong outbreaks by increasing the duration that infected individuals remain infectious. Carcass removal may be a strategy to reduce Bsal transmission and the impacts of outbreaks.

Experimental characterization of four ionization chamber types in magnetic fields including intra-type variation

Background and purposeFor dosimetry in magnetic resonance (MR) guided radiotherapy, assessing the magnetic field correction factors of air-vented ionization chambers is crucial. Novel MR-optimized chambers reduce MR-imaging artefacts, enhancing their quality assurance utility. This study aimed to characterize two new MR-optimized ionization chambers with sensitive volumes of 0.07 and 0.016cm3 regarding magnetic field correction factors and intra-type variation and compare them to their conventional counterparts. Material and methodsFive chambers of each type were evaluated in a water phantom, using a clinical linear accelerator and an electromagnet, as well as a 1.5 T MR-linac system. The magnetic field correction factor kB→,Q, addressing the change of response caused by a magnetic field, was assessed together with its intra-type variation. MR-optimized and conventional chambers were compared using a Mann-Whitney U-Test. ResultsConsidering 1.5 T and a perpendicular chamber orientation, we observed significant differences in the magnetic field-induced change in chamber reading between the two 0.016cm3 chamber versions (p = 0.03). For a 7MV beam, MR-optimized chambers (0.016/0.07 cm3) showed kB→,Q values of 1.0426(66) and 1.0463(44), compared to 1.0319(53) and 1.0480(41) of their conventional counterparts. In anti-parallel orientation, kB→,Q was 1.0012(69) and 0.9863(49) for the MR-optimized chambers. The average intra-type variation of kB→,Q over all chamber types was 0.3%. ConclusionMagnetic field correction factors were successfully determined for four ionization chamber types, including two new MR-optimized versions, allowing their use in MR-linac absolute dosimetry. Evaluation of the intra-type variation enabled the assessment of their contribution to the uncertainty of tabulated kB→,Q.

Investigation of Ionization Chamber Characteristics for Ultrahigh-dose-rate Scanned Carbon-ion Beams.

There are only a few studies on dosimetry with ultrahigh-dose-rate (uHDR) scanned carbon-ion beams. This study investigated the characteristics of four types of ionization chambers for the uHDR beam. We employed a newly developed large-plane parallel chamber to monitor a 208.3-MeV/u uHDR scanned carbon-ion beam with a 110-Gy/s average dose rate. The ionization chambers used were the Advanced Markus chamber (AMC), PinPoint 3D chamber (PPC), Farmer chamber (FC), and large-plane parallel chamber (StingRay). The AMC and StingRay surfaces and the PPC and FC geometric centers were aligned to the radiation isocenter using treatment room lasers. Using the voltage range stated in the instruction manuals, we obtained the saturation curves of the chambers. From these curves, we obtained the ion recombination correction factors using the two-voltage and three-voltage linear methods. The dose linearity was evaluated using five measurement points, and the chamber repeatability was verified by conducting repeated measurements for different dose values. Although all chambers, except for AMC, reached saturation when specified voltages were applied, they exhibited excellent linearity for different dose values. The ion recombination correction factors of the AMC obtained using the aforementioned linear methods were nearly 1. Additionally, all chambers exhibited excellent repeatability. Although the standard deviation of the PPC for the lowest dose was ~1.5%, those of all the other chambers were <1.0%. All ionization chambers can be used for measuring the relative dose, and absolute dose can be conveniently measured using the AMC with an uHDR carbon-ion scanned beam.

Piano Pieces for Children in Serhiy Bortkevych’s Musical Heritage

The article reveals the artistic and pedagogical potential of piano music for children by the Ukrainian Diaspora’s prominent composer Serhiy Bortkevych. For this purpose, we analysed the piano cycles Little Traveller, Marionettes, Musical Wonderland (based on H. H. Andersen’s fairy tales) and From My Childhood. We specified the stylistic features of his music, didactic and educational tasks, which can be determined by working on small pieces of lyrical, dance, scherzo and march genres with their inherent modest scale and simplicity of presentation. S. Bortkevych tends to the chamber type of expression, modesty of texture, and absence of external effects, which reveals the composer’s commitment to the art of the Biedermeier. This component of S. Bortkevych’s creative personality is complemented by his constant interest in the world of childhood, both in terms of imagery and content, as well as didactics and education. All of S. Bortkevych’s children’s piano cycles clearly demonstrate the great importance of programmatic model in revealing the figurative content of piano pieces, in which nature paintings, portrait sketches, emotional experiences, travelling motifs, cities and countries, fairy-tale images, puppetry, etc. take an equal position. Up-tempo pieces (toccata, scherzo) require the same work as etudes, but with the difference that in etudes, artistic tasks are auxiliary, while in music pieces they are the main goal. In dance pieces, the basis for the work is the need to identify the specificity and character of the dance (waltz, mazurka, polka, hopak) and the originality of the rhythm. Lyrical pieces develop musicality, emotionality, artistry and performing initiative due to the musical language accessibility, vivid imagery and laconism of the form. The works of this group are of pedagogical value as they are aimed at gradual mastery of certain piano skills and techniques. S. Bortkevych’s compositional achievements deserve attention in terms of including his heritage in the educational repertoire of modern music institutions to deepen the educational and cognitive process of children’s and youth’s musical and aesthetic education.

Facies Analysis, Diagenetic Features and Depositional Environment of the Kometan Formation from Northeastern Iraq

This study involves microfacies analysis of the Kometan Formation from northeastern Iraq supported by detailed petrographic investigation for the main components and diagenetic processes using a petrographic microscope, scanning electron microscope (SEM), and X-Ray diffraction (XRD). The techniques have revealed that the formation includes two microfacies; lime wackestone and lime packstone microfacies which in turn are subdivided into seven sub-microfacies, that were deposited in the quiet and deep marine environment. Planktonic foraminifera (keeled and globular chamber types) are dominant, along with oligostegina in addition to subordinate benthonic foraminifera and fine-grained bioclasts. Calcite forms the main mineralogical composition in euhedral (rhombohedral), microcrystals, star-shaped, and columnar crystals in addition to pyrite and glauconite. All components are embedded in the micritic groundmass. The main diagenetic processes affecting the studied rocks include; chemical compaction (stylolite formation), dissolution, recrystallization, and cementation.