Radiation Load Research Articles

A model predictive control strategy of global optimal dispatch for a combined solar and air source heat pump heating system

Due to low-carbon transformation of heating sources in northern China, the combination of the solar heating system (SHS) and the air source heat pump (ASHP) has attracted widespread attention due to their significant low-carbon and energy-saving characteristics. Nevertheless, different outdoor meteorological parameters simultaneously affect both the SHS and the ASHP. The heat supply of the SHS is primarily influenced by solar radiation intensity, and the efficiency of the ASHP is mainly constrained by outdoor temperature. The dual uncertainty and volatility of the output capacities of these two heat sources pose significant challenges to their coordinated control. Previous research has primarily focused on traditional rule-based control (RBC) and feedback control, prioritizing the utilization of solar energy while employing ASHP to compensate for heating deficiencies. However, these methods ignore the variations in ASHP efficiency due to fluctuations in outdoor temperature, leading to low whole-system operating efficiency and limiting the flexibility and responsiveness of the control. In this paper, a model predictive control strategy of global optimal dispatch for a combined solar and ASHP (SASHP) heating system is proposed, which focuses on the flexibility and adaptability of dual heat source dispatch under different external conditions. A Temporal Convolutional Network (TCN) was used to establish a solar radiation intensity and load prediction model. A solar heat production prediction was realized by combining the mechanism model based on solar radiation intensity prediction; a two-step room temperature prediction model was established by introducing new input parameters in the load prediction. This strategy achieves globally optimal dynamic planning of the heat supply and duration of the SHS and ASHP systems by considering solar radiation, outdoor temperature, room temperature, and energy consumption, ensuring the efficient and stable operation of the system. Compared to RBC, experimental results indicated that under conditions of sufficient solar energy, the heating proportion of the SHS increased by 31.1 %, the average COP of the ASHP improved by 8.7 %, the energy-saving rate was 14.6 %, and the room temperature control was also more effective; whole-season simulation results showed an average energy-saving rate of 8.35 %.

UV-modified biochar-Bacillus subtilis composite: An effective method for enhancing Cd(II) adsorption from water

The adsorption of Cd(Ⅱ) in sewage by single-modified biochar systems have limitations, whereas composite modification can enhance the efficiency. In this study, reed straw biochar and Bacillus subtilis were used as raw materials. UV radiation was employed to modify the biochar, and subsequently, Bacillus subtilis was loaded onto the biochar by adsorption, creating modified biochar composites. The Cd(II) adsorption performance and removal efficiency of these composites were then investigated. It was characterized by BET, SEM-EDS, FT-IR, XRD and ZETA potential analysis. Adsorption experiments were conducted under varying conditions (initial Cd(Ⅱ) concentration, UV radiation time, initial pH, etc.), with adsorption isotherms and kinetic models used. Results indicated that 24 hours UV radiation significantly enhanced adsorption performance, increasing the biochar’s surface area by 40 % and pore volume by 20 %, and introducing numerous pores and oxygen-containing functional groups to the biochar's surface. Significantly enhancing the saturation adsorption capacity for Cd(II) from 23.98 mg/g to 49.93 mg/g after UV- Modified biochar was loaded with Bacillus. Modified biochar composites performed better compared to single-modified biochar across different initial Cd(Ⅱ) concentrations, particularly in slightly alkaline environments. The primary adsorption mechanisms were chemical adsorption, such as ion exchange and surface precipitation. The synergistic effect of UV radiation and microbial loading significantly enhanced Cd(Ⅱ) adsorption efficiency. This study demonstrates that composite modification is a more efficient method, aiding in the removal of heavy metal ion Cd(Ⅱ) from water.

Potential of thermal protection improvements in large-scale cryostat development

Tremendous efforts are being pursued by experimentalists worldwide in the designing of cryostats to minimize the most dominant radiation heat load over the cryogenic liquid kept inside it. These endeavors are imperative to secure the safe, consistent, and reliable performance of detectors, notably for experiments delving into the investigation of rare physics events, particularly those moving towards ton-scale capacities. In these experiments, maintaining a stable temperature of the cryogenic liquid is crucial. This stability helps in minimizing thermal noise and reducing the loss of cryogenic liquid by mitigating its evaporation rate, and this can be accomplished by reducing the ambient heat load coming from the outer hot wall towards the inner cold wall of the cryostat. Current work scrutinized the impacts of having no insulation, a single-layer insulation, and Multilayer Insulation (MLI) techniques on thermal protection from environmental heat loads at the cryostat’s cold wall boundary, with a particular emphasis on the effectiveness of a single-layer insulation strategy against radiative heat load, a key precursor to MLI technology. The effectiveness of single-layer insulation was quantitatively analyzed for reducing heat load in large-scale rare event searches, using GERDA as an illustrative example and focusing on an optimized configuration. Performance metrics include ambient temperature, cryogenic liquid, emissivity, and the placement of insulation for optimal efficiency. The incorporation of a single intermediate layer positioned near the cold wall boundary results in a significant heat load reduction of 57% for the GERDA geometry compared to a scenario without such a layer. A feasible decrease in emissivity from the customary O(0.01) for insulation materials down to O(0.001–0.0001) could bring about substantial reductions in heat load, potentially by factors spanning approximately 8 to 90. In the scenario involving liquid helium (4.15 K), for example, as the ambient temperature surrounding the cryogen is lowered to (200, 150, 100, 50) K from room temperature, the heat load diminishes by 80%, 94%, 98.8%, and 99.9%, respectively. Moreover, optimally positioning single intermediate layer, crafted from ultra-radiopure material, as close as achievable to the cold wall boundary with minimal emissivity can yield a substantial reduction in heat load, estimated ∼(40–60)%, thereby diminishing the evaporation rate of the cryogenic liquid.

Endoscopic and percutaneous denervation of facet joints in the treatment of patients with degenerative lumbar deformities: comparative analysis

Background. At present, degenerative lumbar scoliosis is considered as the severest form of degenerative diseases of the spine. As a rule, it occurs at the final stage of the disease development. Advanced age of the patients, high comorbidity and poor bone tissue quality increase risk of complications development at any stage of the treatment. All things considered, the majority of specialists continue their search for minimally invasive surgeries able to improve the life quality of patients with such pathology. Aim of the study — comparative analysis of the surgical treatment results of patients with degenerative lumbar deformities operated using percutaneous and endoscopic denervation techniques. Methods. The study enrolled 58 patients: 42 (72.4%) women and 16 (27.6%) men. Median age accounted for 64 (60-69) years, minimum follow-up period — 2 years. In 28 cases, we performed endoscopic denervation of the lumbar facet joints at the apex of the deformity on both sides (group A), in 30 cases — percutaneous radiofrequency denervation in the appropriate volume (group В). Evaluation of the treatment effectiveness was based on the dynamics of pain syndrome (VAS), patients’ quality of life (ODI), as well as on the frequency of complications and repeated surgical interventions. Results. Mean operative duration and radiation exposure were significantly higher in endoscopic intervention (p0.001). Group A showed an earlier reduction in back pain syndrome compared to group B (p0.001). Assessment of patients’ life quality by ODI showed a high degree of correlation with the level of back pain syndrome. Significant complications of the surgical treatment were not revealed in any patient of both groups. Repeated denervation was performed during the two-year follow-up period in 18 patients (60%) of group B and in 2 patients (7.1%) of group A (p0.001). Analysis of the factors associated with the efficacy of percutaneous denervation showed the significance of deformation magnitude in the frontal plane. Efficiency of percutaneous treatment decreased at the deformity value of 30° and more with a sensitivity of 77% and specificity of 67%. Conclusions. A more pronounced decrease in the intensity of back pain syndrome with preservation of the effect during the whole period of follow-up was noted in patients after endoscopic denervation. However, this was accompanied by a longer duration of intervention and radiation load. According to our data, low efficacy of percutaneous denervation is due to the use of this technique in patients with severe deformity of the lumbar spine.

Myocardial Perfusion Scintigraphy in Diagnosic of Coronary Heart Disease

<i>Introduction: </i>Atherosclerosis plays a key role in the etiopathogenesis of cardiovascular diseases. Atherosclerosis is a generalized chronic inflammatory disease of the vascular wall, which results in anatomical and histological changes that, together with functional changes, lead to endothelial dysfunction, narrowing of the arterial lumen, and insufficient blood supply to the tissues. The shift in the incidence of cardiovascular diseases to younger age groups is alarming. The presence of microvascular changes in the myocardium is significant. The high incidence of cardiovascular diseases, especially ischemic heart disease, requires early diagnosis and modern treatment. <i>Aim: </i>The aim of the paper is to analyse and point out early diagnosis of coronary heart disease using nuclear medicine methods. <i>Set of examined patients and methodology: </i>Using nuclear medicine methods, we try to detect these changes in time and thus prevent the occurrence of acute coronary events. In nuclear cardiology, instead of a large-area scintillation detector, a new type of cardio-gamma camera "Discovery CZT 530c" based on the principle of semiconductor detectors began to be used. The abbreviation CZT stands for semiconductor composition (Cadmium-Zinc-Tellur). The set of respondents consisted of 4270 people examined in the years 2014-2016 by myocardial perfusion scintigraphy. There were 950 diabetic patients in the analysed group of the 4270 examined. <i>Results:</i> In the analysed group of 4270 respondents, 61% had negative findings and 39% had positive findings in terms of the presence of ischemic heart disease. In the group of diabetic patients, there was a negative finding in 28% of respondents and a positive finding in 72% of the respondents in the sense of positive ischemic heart disease. Using myocardial perfusion scintigraphy in the diagnosis of functional changes, we confirmed a great benefit in detecting early changes in coronary heart disease, including in the diagnosis of microvascular angina. <i>Conclusion:</i> Nuclear medicine methods are of great benefit for the diagnosis of small vessel disease, diabetic cardiomyopathy and cardiac autonomic neuropathy in patients with diabetes mellitus. The new type of cardio gamma camera "Discovery CZT 530c" allows more accurate assessment of myocardial perfusion abnormalities and at the same time the reduction of the radiopharmaceutical dose reduces the patient's radiation load by 50%.

Effects of grapevine canopy leaning on grape composition and wine quality of ‘Bobal’

Exploring new field strategies for adapting winegrowing regions to the adverse effects of climate change becomes imperative. This study focuses on the effects of canopy architecture through the trellis systems leaning of North–South oriented vineyard’s rows vertical shoot positioned (VSP) system by 30° towards either the East (ESP) or the West (WSP) as a possible adaptation technique. The trial was conducted over two seasons in a Vitis vinifera L. cv. Bobal vineyard located in Requena (Valencia), eastern Spain, under a temperate-warm climate. The canopy leaning was considered to affect the radiation load and its timing with potential effects on vine physiology and grape metabolism and, consequently, on grape and wine quality. Leaning treatments affected vegetative growth, likely due to slight differences in vine water status. In comparison to VSP and ESP, WSP intercepts more light in the morning, when the photosynthetic capacity of the vines is at its highest. However, this results in a more negative vine water potential, which in turn leads to a reduction in vigour with no impact on yield. Musts from the WSP showed a tendency to increase total acidity compared to VSP, while ESP tended to decrease it. This was likely due to the reduction in temperature within the cluster microclimate in WSP in comparison to the ESP and VSP treatments. In addition, musts from the WSP treatment showed higher colour intensity, anthocyanins and polyphenols, potentially attributable to its more negative potentials, likely due to its more negative potentials, which may have prompted the synthesis of phenolic compounds. Consequently, wines from the WSP treatment displayed higher total acidity and lower pH, as well as higher colour intensity, anthocyanins, and polyphenolic content. In addition, WSP wines had higher concentrations of esters and higher alcohols. The improvements in grape and wine composition are likely due to an increased cluster radiation interception in the morning and reduced heating in the afternoon when VPD is higher. Our findings demonstrate that canopy management by leaning VSP vines towards the West can be a useful technique for adapting grape and wine composition to climate change and provide insights into its physiological basis.

An Enhanced Approach for Optimal Design of Hybrid CCHP System Consisting Gas Turbine/Photovoltaic/Thermal Collectors

This paper proposes a hybrid technique for optimizing Combined Cooling, Heating, and Power (CCHP) systems integrating a diverse set of components including geothermal heat pumps, gas turbines, absorption chillers/heaters, and photovoltaic/thermal collectors, along with storage units like batteries and water tanks. The innovation lies in combining the Capuchin Search Algorithm (CapSA) with the Wild Horse Optimizer (WHO) to concurrently optimize primary energy savings, cost reductions, and carbon dioxide emissions. Parametric distributions are used in probabilistic strategies to resolve uncertainty in solar radiation and building load. CapSA optimizes the CCHP system’s design, while WHO enhances its performance. The effectiveness of the proposed strategy is demonstrated through implementation in MATLAB, where it achieves an average ACSR (Average Comprehensive Saving Rate) enhancement of 5.48%. This numerical result highlights a substantial improvement over existing methodologies, showcasing the superior performance of the hybrid optimization approach in enhancing energy efficiency and environmental sustainability of CCHP systems.

Simulator of X-ray Stowage

The development of a functional simulator capable of effectively and accurately positioning patients for X-ray examinations will improve the quality of X-ray images, reduce the effective radiation load on the patient, increase the level of education of specialists in the field of radiology and increase the level of medical care provided to the population. The creation of a database with stacking atlases can be used by medical personnel to enhance their professional skills and improve the quality of research. Improving the accuracy of patient positioning will help to reduce the effective radiation load and increase the level of diagnostic results.

Sputtering of targets in high-intensity heavy-ion beam experiments

Based on available models and experimental data, the sputtering of target atoms in long-term experiments with intense heavy ion (HI) beams has been considered. The experiments on the synthesis of superheavy nuclei (SHN), which are carried out in laboratories around the world, are examples of such experiments encountering the target atoms sputtering in specific conditions. Rotating wheels with a relatively large target annulus area are used in these experiments to reduce the temperature and radiation loads on the target. Large areas of rotating targets allow one to reduce the sputtering yields of target atoms significantly. The question arises about the reliability of these yields in experiments on the synthesis of SHN with Z>118. These nuclei can be produced with extremely low cross sections, requiring HI beam doses exceeding 10 20 particles passed through the target to observe several decay events of the thus synthesized SHN. Estimates based on approximations and simulations considered in this work are presented and compared with some data on actinide target sputtering obtained in experiments performed on the synthesis of SHN.

Technique of Reactor Experiments of Tin-Lithium Alloy Interaction with Hydrogen Isotopes Under Neutron Irradiation Conditions

The implementation of the ITER and DEMO projects currently includes the investigation of the structural and functional material properties of fusion reactors (FRs). Research to support the use of liquid metals and alloys as plasma-facing materials (PFMs) is a crucial area of work during the development of new FRs. Recent studies indicate the prospects of the tin-lithium (Sn-Li) alloy as a new liquid metal for protecting the in-vessel elements of a FR from the energy flows and high-density particles. Sn-Li alloy has been widely explored for utilization as PFM; however, there is a shortage of investigations being performed at nuclear reactors. The utilization of Sn-Li alloy as PFM in a FR must be fully justified by validated experimental results on tests under extremely high heat, plasma, and radiation loads. The paper presents the methodology of in-pile experiments performed at the IVG.1M research reactor (Kurchatov, Kazakhstan) to study the interaction of hydrogen isotopes with Sn-Li alloy under neutron irradiation conditions. A Sn-Li sample with 73 at. % tin and 27 at. % lithium was manufactured. A unique experimental ampoule device (AD) with a Sn-Li sample had been developed and manufactured for in-pile tests. The results of neutron-physical and thermophysical calculations of designs of the experimental device with Sn-Li alloy under irradiation conditions of the IVG.1M reactor were performed to justify the AD design. Methodical experiments were performed to determine the temperature dependence of the change in the composition of the gas phase in the chamber with Sn-Li alloy. The time dependence of the partial pressure of hydrogen, tritium, and tritium-containing molecules in the AD volume with the Sn-Li alloy on its temperature under reactor irradiation conditions at a power of 3 MW has been studied. Key findings include the successful measurement of tritium release, the determination of temperature conditions for tritium generation and release, and the validation of our experimental AD for conducting such studies.

Rheological and microscopic characterization and correlation analysis of asphalt under high-intensity ultraviolet radiation

The lower radiation intensity (2–20 W/m2) was widely used for asphalt ultraviolet (UV) aging. The effect of high-intensity radiation on asphalt properties and microscopic morphology is unknown. This study investigated the rheological behavior, microscopic characterization, and correlation analysis of SBS modified asphalt under high-intensity UV radiation. Rheological properties tests encompassed temperature sweep (TS), multiple stress creep recovery (MSCR), and frequency sweep (FS). Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and Gel Permeation Chromatography (GPC) tests were performed to reveal the microscopic characterization. In the early stages of UV aging, the rutting factor of asphalt was increased. The increment decreased as the UV aging time increased. The UV aging process did not alter the temperature sensitivity of asphalt. The complex shear modulus was influenced by UV radiation duration and loading frequency. Extended exposure to high-intensity UV radiation resulted in the formation of microcracks on the surface of the asphalt. The maximum molecular weight of the UV-aged asphalt was higher than that of the original asphalt. The degraded SBS modifier deteriorated the homogeneity of asphalt. The sulfoxide aging index, carbonyl aging index, number-average molecular weight (Mn), weight average molecular weight (Mw), and polymer dispersity index (PDI) presented a better correlation with rheological behavior indexes. The correlation between small molecule size (SMS), medium molecule size (MMS), and large molecule size (LMS) with rutting factor and complex shear modulus was poor. It was worth mentioning that the correlation between the MSCR test results and microscopic performance indicators was the best. Especially for the recovery rate and Jnr at 3.2 kPa, the mean absolute value of the correlation coefficient was 0.953.

МИГРАЦИИОННАЯ АКТИВНОСТЬ 137CS В АГРОПРОДУКЦИЮ БИОГЕОЦЕНОЗОВ КРАСНОЯРСКОГО КРАЯ

The purpose of the study is to determine the intensity of 137Cs movement along the trophic chain “soil – diet – livestock products” in the agricultural landscapes of the Krasnoyarsk Region with additional radiation load. A literature review of scientific data characterizing the features of the migration activity of 137Cs in the links “soil – feed – livestock products” in agrobiocenoses with radioactive contamination above established standards is given. Based on the results of a radioecological survey of agricultural landscapes in the central regions of the Krasnoyarsk Region and calculation of absorbed doses, the author identified agricultural landscapes with additional technogenic pollution and determined the specific activity of 137Cs in feed and cow's milk in agricultural landscapes with additional technogenic load. The specific activity values of 137Cs in agricultural landscape feeds with doses of 1.33 and 1.55 mGy/year are higher than the background va¬lue for the Krasnoyarsk Region. The content of 137Cs in livestock products produced in farm biogeocenoses with additional technogenic load is higher than the average for the region, but does not exceed the criterion of regulatory documents; accordingly, radiation-safe agricultural products are produced on the territory of the Krasnoyarsk Region. For agricultural landscapes with absorbed doses of 1.33 and 1.55 mGy/year, a KP for the link “feed – livestock products” has been established. When the radioecological situation changes, the established Kp values can be used to predict the migration of 137Cs in the chain “soil – feed – livestock products”. A direct linear moderate Spearman rank correlation was identified between the specific activity of 137Cs in feed and the concentration of 137Cs in cow's milk. Linear regression equations have been determined to determine the specific activity of cow's milk based on data on the specific activity of 137Cs in feed. The revealed direct linear relationship indicates that even a slight increase in the 137Cs activity of the diet leads to an equivalent increase in the specific activity of technogenic cesium in cow's milk.

Giant subcapsular hematoma of the liver — a rare complication after laparoscopic cholecystectomy

The article shows a clinical case of an extremely rare complication after laparoscopic cholecystectomy — a giant subcapsular hematoma of the liver. The clinical, laboratory and instrumental data of the patient and the results obtained were analyzed. Analysis of the data from the operated patient did not reveal the main reason that could have caused the development of a giant subcapsular hematoma of the liver. The patient had no bleeding disorders, had not previously suffered any bleeding, and did not take anticoagulants as an outpatient. During the operations, no source of bleeding or damage to the liver parenchyma was identified. In addition, there was no evidence of focal liver lesions according to the preoperative ultrasound scan. Outpatient use of a drug from the group of antiplatelet agents, as well as short-term irregular use of analgesics to relieve periodic pain could provoke the development of this complication. Treatment of subcapsular hematoma of the liver mainly depends on the clinical condition of the patient and the size of the hematoma. With conservative management, the condition of the formed hematoma should be more carefully monitored over time using radiation diagnostic methods. If necessary and according to indications, do not exclude possible repeated laparoscopic intervention, including conversion to laparotomy, taking into account the data of clinical, laboratory and radiological research methods. In most cases, this condition requires conservative treatment. Patients with such a complication require careful hemodynamic monitoring and visual monitoring of the complications development. Probably, preference should be given to magnetic resonance imaging, since this method is the most objective and does not carry a radiation load. The main task is not to miss the moment of hematoma rupture and the development of fatal bleeding.

Analysis of electromagnetic and radiative heat source on tangential hyperbolic fluid under Arrhenius kinetic with convective cooling

The global threat of environmental degradation from harmful waste discharge is evident, leading to unusual diseases and natural disasters. Some of these toxic emissions result from human activities, such as the incomplete combustion of hydrocarbons. As such, this study aims to explore the analysis of electromagnetic and radiative heat sources on tangential hyperbolic fluid under Arrhenius kinetic with convective cooling. The transformed momentum and heat equations are solved using a rigorous computational approach called the Galerkin integration approximation with weighted residual method. This computational methodology ensures the reliability and accuracy of the results. Various graphs illustrate the results, showing parametric sensitivity profiles for the velocity, temperature, skin friction, thermal gradient, Bejan, and entropy generation. As noticed from the outcomes, electric field loading increases heat dispersion by about 3.25 % as heat source terms are enhanced. Increasing magnetic field, radiation, and electric field loading parameters strengthened thermodynamic equilibrium and minimized entropy generation. The tangential hyperbolic combustion process is 6.11 % increased with rising Brinkman number and electric field loading terms. The flow rate and temperature field are increased to the peak along the middle of the channel for increasing pressure gradient.

Measurement of microclimates in a warming world: problems and solutions.

As the world warms, it will be tempting to relate the biological responses of terrestrial animals to air temperature. But air temperature typically plays a lesser role in the heat exchange of those animals than does radiant heat. Under radiant load, animals can gain heat even when body surface temperature exceeds air temperature. However, animals can buffer the impacts of radiant heat exposure: burrows and other refuges may block solar radiant heat fully, but trees and agricultural shelters provide only partial relief. For animals that can do so effectively, evaporative cooling will be used to dissipate body heat. Evaporative cooling is dependent directly on the water vapour pressure difference between the body surface and immediate surroundings, but only indirectly on relative humidity. High relative humidity at high air temperature implies a high water vapour pressure, but evaporation into air with 100% relative humidity is not impossible. Evaporation is enhanced by wind, but the wind speed reported by meteorological services is not that experienced by animals; instead, the wind, air temperature, humidity and radiation experienced is that of the animal's microclimate. In this Commentary, we discuss how microclimate should be quantified to ensure accurate assessment of an animal's thermal environment. We propose that the microclimate metric of dry heat load to which the biological responses of animals should be related is black-globe temperature measured on or near the animal, and not air temperature. Finally, when analysing those responses, the metric of humidity should be water vapour pressure, not relative humidity.

Static and dynamic fracture toughness of graphite materials with varying grain sizes

Graphite materials play critical roles as moderators, reflectors, and core structural components in high-temperature gas-cooled nuclear reactors. During the reactor operation, graphite materials may experience a variety of loads, including thermal, radiation, fatigue, and dynamic loads, potentially leading to crack initiation and propagation. Therefore, it is imperative to investigate their fracture properties. Despite this, there remains a paucity of comprehensive studies on the fracture toughness of graphite materials with varying grain sizes, particularly concerning dynamic fracture toughness. This study addresses this gap by employing a digital-image-correlation-based virtual extensometer to analyze crack propagation in graphite materials of different grain sizes, enabling precise measurement of crack propagation length and fracture toughness. Findings reveal that static fracture toughness increases with larger grain sizes, while under dynamic loading, smaller grain sizes exhibit greater fracture toughness. Additionally, dynamic fracture toughness shows a near-linear increase with impact speed. Scanning electron microscopy analysis of fracture surface morphology highlights the impact of grain size and impact speed on fracture toughness. Nuclear graphite specimens with larger grain sizes have more irregular grain and pore distributions, enhancing crack deflection and propagation resistance, thereby increasing fracture toughness. The observed loading rate dependence of dynamic fracture toughness is attributed to a gradual transition from intergranular to transgranular fracture modes with increasing impact speed.

Thermal degradation of self-contained breathing apparatus facepiece lenses under radiant thermal loads

The self-contained breathing apparatus is one of the most critical components of the firefighting personal protective ensemble providing protection from potentially toxic gases and products of combustion. Three models of self-contained breathing apparatus facepiece lenses meeting various editions of national standards were exposed to radiant thermal loads of 5, 10, 15, and 20 kW/m2 until thermal degradation resulted in hole formation or the test duration reached 30 min. Thermal damage was documented as time to crazing, bubbling, and hole formation. Temperature was recorded within the facepiece. There were significant differences in times to thermal damage between lenses. The facepiece lens model meeting the 2013 edition of National Fire Protection Association 1981 had significantly longer times to thermal degradation than those meeting older editions of the standard. Maximum temperatures were higher in the facepiece model meeting the 2013 edition of National Fire Protection Association 1981, likely because of the extended time the radiant load was applied.

Micro-macro performance evolution behavior of fine-grained porous asphalt mixture exposed to ultraviolet-water-heat-load coupling action

In the Yangtze River Delta of China, porous asphalt pavement is significantly affected by UV radiation, water, heat, and traffic load. Therefore, research on its long-term performance evolution behavior under multi-factor coupling effect contributes to conducting engineering practice. The key pavement performance evolution of fine-grained porous asphalt mixture (PA-13), using SBS/crumb rubber (CR) composite modifier or TPS modifier, with multiple void ratios was studied. The evolution of high-temperature stability, water stability, and meso-drainage performance of PA-13, among the simulated 5-year service process, was respectively evaluated by dynamic creep test, immersion Marshall test, CT scanning and three-dimensional reconstruction. The findings demonstrate that the negative impacts of coupled conditions are mainly concentrated in the later stage of service. Under cyclic effect, the good anti-permanent deformation ability of SBS/CR PA-13 helps to alleviate the attenuation of its void structure and permeability. Besides, the transverse connectivity of void is more obvious than the vertical connectivity throughout the entire service process. In general, SBS / CR PA-13 has better anti-attenuation ability than TPS PA-13 in high temperature stability, water stability and drainage performance, indicating SBS/CR porous asphalt mixture is more suitable for application in high temperature and rainy areas.

Investigation of VVER-1000 fuel assembly bowing effect on power distribution during cycle using neutron noise adiabatic approximation

Thermomechanical and radiation loads in the reactor core cause lateral changes in the shape of Fuel Assemblies (FAs). This phenomenon, known as FA bowing, has significant implications for reactor safety and operation. Bowing results in alterations to the spacing between FAs, which in turn leads to neutron flux perturbations affecting power distribution. These perturbations are time-dependent due to variations in boric acid concentration during the cycle. Neutron noise theory is employed to analyze these time-dependent neutron perturbations. In this research, it is investigated the bowing effect during the cycle in a VVER-1000 reactor using the neutron noise adiabatic approximation. It was initially considered a VVER-1000 reactor core to verify the calculations algorithm without bowed FAs. Results had acceptable accuracy in power, initial boric acid, and cycle length. Subsequently, it was explored various modes of FA bowing as neutron noise sources the results revealed that the power noise caused by bowing varies throughout the cycle, as expected. The noise amplitude during the cycle depends on changes in boric acid concentration, burnup, size, and the direction of bowing.

Patient satisfaction with ultrasound, whole-body CT and whole-body diffusion-weighted MRI for pre-operative ovarian cancer staging: a multicenter prospective cross-sectional survey

BackgroundIn addition to the diagnostic accuracy of imaging methods, patient-reported satisfaction with imaging methods is important.ObjectiveTo report a secondary outcome of the prospective international multicenter Imaging Study in Advanced ovArian...