Degree Of Closure Research Articles

Study on fatigue crack growth behavior of selective laser‐melted Ti6Al4V under different build directions, stress ratios, and temperatures

AbstractThe experimental study of fatigue crack growth (FCG) behavior in Ti6Al4V alloy manufactured by selective laser melting (SLM) was carried out on an in situ fatigue testing machine. Two specimen orientations relative to the build direction (horizontal and vertical), two temperatures (room temperature, RT, and 400°C), and two stress ratios (0.1 and 0.5) were considered, and the FCG curves with the threshold values were determined. The results showed that the FCG properties were affected by the stress ratio due to different degree of crack closure and temperature with grain softening at 400°C in threshold and Paris region. The threshold value is highly dependent on the build direction of the alloy, which was caused by the anisotropic microstructure, while in the Paris region, the effect of material direction can be negligible and FCG rate tends to be consistent. The fracture mechanism at different stages was discussed and revealed by the fracture morphology observation using scanning electron microscopy.

A discrete numerical model for the effects of crack healing on the behaviour of ordinary plain concrete: Implementation, calibration, and validation

In the last decade the self-healing of cracks in cementitious materials has been gaining an increasing interest by both the concrete industry and the scientific community. Framed into the Horizon 2020 project ReSHEALience, the present research work aims to formulate a proposal for the numerical modelling of autogenous and stimulated autogenous healing in ordinary plain cement-based materials, whose composition is enriched, in the latter case, with crystalline admixtures. In this paper a meso-scale discrete model that also considers the healing process is presented, relying on the coupling and the enhancement of two models: the Hygro-Thermo-Chemical model, for the simulation of chemical, moisture and heat transport phenomena, and the Lattice Discrete Particle Model, for the mechanical part. The evolution of the healing phenomenon is implemented into the HTC discrete formulation, in order to simulate the degree of crack closure over time. The latter is then employed to capture how the self-repairing affects both moisture permeability and mechanical performances. Finally, the results of a laboratory campaign, carried out at the Politecnico di Milano, are used for calibrating and validating the model presented.

A study of 285 cases of cranial vault suture closure in Chinese adults.

To examine the presence and characteristics of cranial vault suture closure in Chinese adults and to explore whether craniosacral therapy (CST) manipulation is rational from the anatomical perspective. Anthropological non-metric observation and craniometry were used to study 285 dry skull specimens of Chinese adults. A total of 91 specimens with closed extracranial sutures were observed, with an occurrence rate of 31.93%. Based on the mode of closure, there were 32 cases of single type closure, with sagittal suture closure predominating with 20 cases (21.98%); 59 cases of composite closure, with a partial closure of coronal suture + sagittal suture + lambdoid suture predominating with 26 cases (28.57%). In terms of the degree of closure, there were 13 cases (14.28%) of sagittal suture grade 0 closure and 78 cases (85.72%) of grade 1 - 4 closure; 34 cases (37.36%) of coronal suture grade 0 closure and 57 cases (62.64%) of grade 1 - 4 closure; 47 cases (51.65%) of lambdoid suture grade 0 closure and 44 cases (48.35%) of grade 1 - 4 closure. The segment and degree of coronal suture closure (46, 80.7%) and lambdoid suture (31, 70.45%) were mostly left-right symmetrical. The bone surfaces on either side of the cranial vault sutures are embedded in each other, forming a rough, complex and interlocking bone-suture-bone structure. This study observed the closure of the cranial vault suture, summarized its characteristics, and explored the irrationality of the CST manipulation. The anatomical characteristics of the cranial suture dictate that manipulation cannot push the cranial suture at will.

Higher education non-completion, employers, and labor market integration: Experimental evidence

Theories of job assignment suggest that employers give a lot of weight to achieved educational credentials. But what if credentials are missing? We theorize how college non-completion affects the hiring chances, identify its causal effect in different labor market segments, and assess which factors facilitate labor market entry for dropouts. Based on a simulated hiring process with N = 1382 German employers who rated more than 10,000 fictitious CVs, we show that college non-completion is not a scar per se, but rather depends on the educational attainment of the competitors who constitute the labor queue, and on the degree of occupational closure which varies on a granular level between firms that hire for the same occupations. We also find that employers, when rating dropouts, attach most value to CV attributes that signal a high stock of job-relevant skills, such as good performance during college or an occupation-specific internship. We conclude by discussing implications of our work for research on the labor market integration of dropouts.

Impact of APRF+ in Combination with Autogenous Fibroblasts on Release Growth Factors, Collagen, and Proliferation and Migration of Gingival Fibroblasts: An In Vitro Study.

The present study aimed to compare the action of advanced platelet-rich fibrin (A-PRF+) alone with the action of A-PRF+ combined with autologous gingival fibroblasts. The components released from A-PRF+ conditioned with autogenous fibroblasts that were quantified in the study were fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF), trans-forming growth factor-beta1 and 2 (TGFβ1 and TGFβ2), and soluble collagen. A-PRF+ combined with fibroblasts demonstrated significantly higher values of released VEGF at every time point and, after 7 days, significantly higher values of released TGFβ2. A viability test after 72 h showed a significant increase in proliferation fibroblasts after exposition to the factors released from A-PRF+ combined with fibroblasts. Similarly, the degree of wound closure after 48 h was significantly higher for the factors released from A-RRF+ alone and the factors released from A-RRF+ combined with fibroblasts. These results imply that platelet-rich fibrin (PRF) enhanced with fibroblasts can be an alternative method of connective tissue transplantation.

Interacting effects of density and temperature on fish growth rates in freshwater protected populations.

Despite the demonstrated benefits of marine protected areas, there has been relatively little dialogue about freshwater protected areas (FPAs) even though some have been established to protect freshwater species from recreational and commercial fishers. After populations recover from fishing pressure, abundances and densities of formerly fished species increase, and we should therefore expect changes in demographic traits compared to those in exploited populations. To test this, we used capture-mark-recapture data for 10 Galaxias maculatus populations across a density gradient mediated by different degrees of fishery closure. We examined the extent to which density-dependent (DD) and density-independent (DI) effects interact to affect specific growth rates in post-recruit populations. We found that population density, stream temperature and individual size interact to affect growth rates. When population densities were high, compensatory responses of far slower growth rates were strongest, indicating that DD growth is a key mechanism regulating post-recruit populations of G. maculatus. This study emphasizes the importance of understanding DD and DI processes, their interactions, function and effectiveness for freshwater fisheries management. For FPAs to be effective, the extent and quality of target species' habitats must serve as key criteria for protection to alleviate competition for limited resources that underpins DD processes.

Morphology of the Occipital Bones and Foramen Magnum Resulting From Premature Minor Suture Fusion in Crouzon Syndrome.

To identify skull-base growth patterns in Crouzon syndrome, we hypothesized premature minor suture fusion restricts occipital bone development, secondarily limiting foramen magnum expansion. Skull-base suture closure degree and cephalometric measurements were retrospectively studied using preoperative computed tomography (CT) scans and multiple linear regression analysis. Evaluation of multi-institutional CT images and 3D reconstructions from Wake Forest’s Craniofacial Imaging Database (WFCID). Sixty preoperative patients with Crouzon syndrome under 12 years-old were selected from WFCID. The control group included 60 age- and sex-matched patients without craniosynostosis or prior craniofacial surgery. None 2D and 3D cephalometric measurements. 3D volumetric evaluation of the basioccipital, exo-occipital, and supraoccipital bones revealed decreased growth in Crouzon syndrome, attributed solely to premature minor suture fusion. Spheno-occipital (β = −398.75; P < .05) and petrous-occipital (β = −727.5; P < .001) suture fusion reduced growth of the basioccipital bone; lambdoid suture (β = −14 723.1; P < .001) and occipitomastoid synchondrosis (β = −16 419.3; P < .001) fusion reduced growth of the supraoccipital bone; and petrous-occipital suture (β = −673.3; P < .001), anterior intraoccipital synchondrosis (β = −368.47; P < .05), and posterior intraoccipital synchondrosis (β = −6261.42; P < .01) fusion reduced growth of the exo-occipital bone. Foramen magnum morphology is restricted in Crouzon syndrome but not directly caused by early suture fusion. Premature minor suture fusion restricts the volume of developing occipital bones providing a plausible mechanism for observed foramen magnum anomalies.

Gender Disparities in the Coronal Suture Closure of the Cranium – A tool for estimation of sex

Background: Establishing the identification of a deceased at autopsy is one of the prime objective of medicolegal postmortem examination. The identification starts with determination of age and sex of the individual. The problem arise when completely decomposed dead body or just skeletal remains are brought for postmortem examination. Methods: The study was conducted on 90 dead bodies of equal proportion from both the genders in the year 2016 for a period of nine months. The cases were selected for study after careful scrutiny through a pre-trialed questionnaire with certain selection criteria. After proper exposure of the inner and outer surface of the cranial vault the degree of coronal suture closure was assessed in three segments as C1, C2 and C3 as observed through Acsádi‐Nemeskéri Scale. Results: A grossly significant observation of possibility of determination sex both from ectocranial and endocranial suture closure of the coronal suture with 0.001 p value was noted, therefore establish the fact that determination of sex from closure coronal suture is established. Keywords: Sex, Coronal, Suture, Closure

Drowsiness Detection using EEG signals and Machine Learning Algorithms

Drowsiness is described as a state of reduced consciousness and vigilance accompanied by a desire or want to sleep. Driver tiredness is frequently detected using wearable sensors that track vehicle movement and camera-based systems that track driver behavior. Many alternative EEG-based drowsiness detection systems are developed due to the potential of electroencephalogram (EEG) signals to observe human mood and the ease with which they may be obtained. This paper applies Deep learning architecture like Convolutional Neural networks (CNN) and algorithms for the classification of EEG data for Drowsiness Detection. The key measures of video-based approaches include the detection of physical features; nevertheless, problems such as brightness limitations and practical challenges such as driver attention limits its usefulness. The main measure of video-based methods is the degree of closure of the eyelids; however, its success is limited by constraints like as brightness restrictions and practical challenges such as driver distraction. We have extracted statistical features and trained using various classifiers like Logistic Regression, Naïve Bayes, SVM, and K Nearest Neighbours and compared the accuracy using a deep learning CNN model. Results demonstrate that CNN achieved an accuracy of 94.75% by delegating feature extraction on itself. Upon comparing existing state–of–the–art drowsiness detection systems, the testing results reveal a higher detection capability. The results show that the the suggested method can be used to develop a reliable EEG-based driving drowsiness detection system.

Weight changes of children in 1 year during COVID-19 pandemic

Abstract Introduction The coronavirus disease 2019 (COVID-19) pandemic has changed everyday life. The Korean government urged schools to close as a measure of social distancing, and children and adolescents seemed to gain weight due to home confinement. We aimed to investigate the trends in weight changes in children during the pandemic period. Materials and Methods This retrospective study included 139 children aged between 6 and 12 years who visited the pediatric endocrine clinic for regular growth follow-up for 1 year during the COVID-19 pandemic. We analyzed changes in the body mass index (BMI), BMI z-score, and proportion of children who were overweight or obese over a period of 1 year. Results The BMI and BMI z-scores of the 139 children increased significantly over the year. The increase was maximum during the first three months of the COVID-19 pandemic, with little change between the third and sixth month of the pandemic. The proportion of children who were overweight or obese increased over time, from 24.5% at the COVID-19 pandemic baseline to 38.1% 1 year later (p < 0.001). Conclusions The COVID-19-related lockdown resulted in significant weight gain in Korean children. Changes in BMI showed different trends depending on the degree of school closure. An overall shift from normal weight to overweight or obesity was observed during the pandemic period.

Gas-hydrogeochemical conditions of the Bilche-Volytsia oil-gas-bearing area (Carpathian foredeep, Ukraine)

Introduction. Water-dissolved gases in exploratory oil and gas hydrogeology are the fundamental criteria of oil and gas potential. Their quantitative and qualitative characteristics allow to study the conditions of formation and preservation of the hydrocarbon deposits and to identify the perspective searching areas. The purpose of article was to determine the vertical and lateral gas-hydrogeochemical zonation of the Bilche-Volytsia oil and gas zone, to assess the role of water-dissolved gases in the formation of gas fields with the prospect of predicting new hydrocarbon deposits. The research methods base on the calculation and interpretation of the following parameters: gas saturation of water, saturation pressure, gas saturation coefficient. Graphs of dependences based on experimental studies from published scientific publications were used to determine the solubility of methane. The results of research. Nitrogen-methane composition of water-dissolved gases of the Upper Jurassic and Upper Cretaceous aquifers in combination with specific geochemical characteristics of groundwater of the north-western and central parts of the Bilche-Volytsia OGBA indicate the open hydrodynamic conditions, which, in general, are unfavourable for the formation and preservation of hydrocarbon deposits. In deep-submerged reservoirs of the south-eastern part of this area, water-dissolved gases of the Upper Jurassic and Upper Cretaceous aquifers are characterized by high contents of methane homologues. In the Upper Badenian aquifer the lateral distribution of water-dissolved methane is presented in the growth of its portions from the West and East European platforms in the direction of the sub-submerge of the Carpathians, which is due to an increase in the degree of hydrogeological closure of structures. Increased methane contents also spatially tend to transverse tectonic faults, which determines their role in the vertical migration of water-hydrocarbon mixtures. Water-dissolved gases of the highly productive Lower Sarmatian aquifer are mainly methane, occasionally nitrogen-methane. The gas saturation of the waters directly correlates with the proximity to gas deposits. Laterally, the portion of water-dissolved methane is directly correlated with TDS of water, the high values of which accordingly reflect the structures of a high degree of hydrogeological stagnation. Conclusions. The portions of water-dissolved methane increase from the West and East European platforms in the direction of the sub-submerge of the Carpathians, which is effect of higher degree of hydrogeological closure of structures. It has been established that water-dissolved methane, nitrogen and carbon dioxide have different sources of origin and different spatiotemporal mechanisms of water saturation. The hydrodynamically closed structures (favourable for the formation and preservation of hydrocarbon deposits) characterized by high relative and absolute contents of dissolved methane. Increased methane contents also spatially tend to transverse tectonic faults, which determines their role in the vertical transportation of water-hydrocarbon mixtures. Deep hydrodynamically closed aquifers of the Bilche-Volytsia OGBA often are marked by high nitrogen contents of non-air origin. Its source can be rock organic matter, bound rock nitrogen released during metamorphism, nitrogen of deep genesis.

P149 THE IMPACT OF COVID-19 ON TACKOMESH RANDOMISED CONTROLLED TRIAL COMPARING SPIRAL-TACK MESH-FIXATION DEVICES IN LAPAROSCOPIC INCISIONAL HERNIA REPAIR USING THE MANCHESTER TECHNIQUE

AimProvide a report on all patients who underwent laparoscopic incisional hernia repair as part of the TACKoMesh RCT prior to unblinding of treatment arms.Material and MethodsTrial recruitment was for primary incisional hernia with a defect diameter of 3–10cm. 63 patients (target 74-136) were operated on prior to the outbreak of COVID-19. Post-operative pain is the primary trial outcome.Surgery was performed with either spiral-tack mesh-fixation device (Protack (permanent) or Reliatack (absorbable)), Symbotex IPOM mesh, and fascial closure with no 1 Maxon suture(s) using extracorporeal knot ties – the Manchester Technique.Data was collected on trial forms and lifestyle questionnaires (SF-36 and CCS). All data were explored and described in RStudio v1.4.1106.ResultsPatients were aged 36-80 and 36(57.1%) patients were male. Mean preoperative BMI was 30.91(sd5.11,range21.15–43.93).Mean operating time was 80.81(37.34,20-240)minutes. In 13(20.6%) patients multiple hernia defects were identified. A good degree of fascial closure was achieved in all patients using a median of 3(IQR 2.0-3.5)knots.Median mesh-fixation time was 286(159.5-428.0)seconds and a mean 25.24(5.49,14-41)tacks/patient were used. Median length of hospital stay was 3.5(2.0–6.0)days.Patients were asked “Please indicate on this scale [VAS 0–10] the pain that you currently experience from your incisional hernia during activity?”. Median responses for Day0/pre-op, Day1, Day6, Day30 and Day365 were 4.5, 8.0, 6.0, 3.0 and 1.5 respectively.At one year, 7(11%) patients had experienced hernia recurrence and 33(52%) post-operative seroma.ConclusionsTarget recruitment was not possible owing to COVID-19. The Manchester Technique has comparable recurrence rates. Reported pain increases post-operatively but is reduced at post-operative day30 and day365.

Acute Compartment Syndrome Following Thrombolysis For Acute Lower Limb Ischemia

Acute Compartment syndrome (ACS) with subsequent need for fasciotomy is a serious and insidious complication after revascularization for acute lower limb ischemia (ALI). The development of ACS during endovascular catheter directed thrombolysis is particularly difficult to identify. The aim was to identify the incidence, predisposing factors, wound treatment, and outcome in terms of amputation and survival for patients presenting with ALI that develop ACS during catheter directed thrombolysis. Patients who did not develop ACS after thrombolysis were analyzed as controls. Descriptive retrospective analysis of prospective databases from two large tertiary-referral vascular centers. Patients with ACS after thrombolysis for ALI between 2001-2017 were analyzed. Seventy-eight cases and 621 controls were identified. Mean age was 72 years and 30 (38.5%) were women in the ACS group. Patients that developed ACS presented with significantly more severe preoperative ischemia. With 38.5% having Rutherford 2b classification as compared to 22.7 % in the control group (P=0.002). Occluded popliteal artery aneurysms were also associated with a higher incidence of ACS (P=0.041). Treatment of the fasciotomy wound was most commonly treated with regular wound dressing in 45 (58%) of cases, while wound dressing and foot pump and vacuum assisted closure were used in 14 (18%) and 19 (24%) respectively. These differing approaches did not affect the number of wound infections and amputations, which was similar regardless of treatment type. Vacuum assisted closure was associated with a higher degree of skin graft closure (P=0.001). The median time to complete wound closure was 10 days. One year after thrombolysis, the major amputation rate in the ACS group was 31% as opposed to 17% in control group, P=0.003. Mortality measured at 16.7% and 15.3%, respectively, P=0.872. Amputation-free survival in the ACS group was 62% vs. 73% in the control group, P=0.035. These differences level out, however, when applying long-term analysis of amputation-free survival in Kaplan-Meier analysis (log-rank 0.103). Patients that developed ACS during endovascular CDT presented with a more severe pre-operative ischemia, more occluded popliteal artery aneurysms and had a higher amputation rate during the first year, compared to controls. The development of ACS during endovascular treatment of ALI with thrombolysis is not uncommon and warrants both clinical awareness and rapid treatment.

Robotic-Assisted Partial Nephrectomy: Techniques to Improve Clinical Outcomes.

To summarize current options available for robot-assisted partial nephrectomy RECENT FINDINGS: Partial nephrectomy (PN) is a standard treatment option for management of cT1 renal masses. It may be carried out by multiple approaches. Robot-assisted (RA) PN is one such option. The goal of treatment is both correct oncological (negative surgical margins) and functional (preservation of sufficient amount of renal parenchyma of the operated kidney) outcome. Appropriate outcomes depend on multiple factors. There are many, but among others tumor characteristics (size, location, i.e., tumor complexity), patient baseline renal function, patient comorbidities, and performance status etc. Based on all these, the surgeon adapts the intervention for each mass/patient by preoperative planning, absence/use/duration of warm or cold ischemia, perioperative imaging, resection technique adapted to tumor location and depth of invasion, use of hemostatics, type and degree of renal parenchymal closure and others details. Nephroprotective agents have not shown efficacy so far. It should not be forgotten that surgeon's experience plays a key role in the achievement of good results. Although multiple factors have a role in the RA partial nephrectomy, surgeon experience and adaptation of technique of intervention have the crucial role in the achievement of both functional and oncological results.

Experimental investigation on the multiphase flow characteristics of oblique water entry of semi-closed cylinder

The multiphase flow characteristics of the oblique water entry of semi-closed cylinders is investigated experimentally. The results from the experiment are used to analyze the flow mechanism and to validate the numerical simulations. In the experimental setup, a high-speed photography technique is used to capture the process of water entry based on digital video images. It can be observed that the cavity is formed in three (3) flow modes namely the fluctuation cavity, the transition cavity, and the blurry rippling cavity. The transparency of the cavity surface decreases, while the fragmentary and blurry rippling increases, with an increasing inclined angle of the cylinder. Owing to the instability of internal flow structure and the degree of cavity closure, the cavities of three (3) flow modes occur in sequential order from clear fluctuant cavity, rippling fluctuant cavity, to continuous blurry and fragmentary ripples. The cavity evolution is also found to affect the structure of multiphase flow field and the dynamic characteristics of semi-closed cylinder.

Common Patterns of Skull Bone Fusion and Their Potential to Discriminate Different Ontogenetic Stages in Extant Birds

The degree of sutural closure between bones generally allows for the classification of skeleton maturity in tetrapods. In mammals, the sutural closure of skull bones was previously used as proxy to evaluate the ontogenetic stage of single individuals. However, due to temporal variation, this process can be only applied among mammalian subclades, but not for all mammals in general. In contrast, the process of sutural closures in bird skulls could be a more reliable ontogenetic proxy for this clade as adult birds commonly show a generally high degree of bone fusion. To test this, we studied the process of sutural closure in ontogenetic series of 18 extant bird species regarding the presence of an ontogenetic signal and compared the results with changes in skull size and proportions. Univariate analyses indicate that bone fusion happens faster in altricial than in precocial birds. However, the use of PCoA and multivariate regressions reveal that the skull bone fusion follows a common pattern among birds and thus can be used as proxy to identify different ontogenetic stages. In general, the process of sutural closure spreads from posterior to anterior and from ventral to dorsal. In contrast, skull measurements reflect rather interspecific allometry than ontogeny. The used of bone fusion as proxy will help to better identify and compare different stages of maturation in birds, including historical material from osteological collections.

Ambrosia Beetles Prefer Closed Canopies: A Case Study in Oak Forests in Central Europe

Research Highlights: The percentage of canopy closure was found to be the main factor associated with ambrosia beetle abundance and species richness. The latter two variables increased as canopy closure increased, probably because a high percentage of canopy closure provides a stable and humid environment suitable for the growth of ambrosia fungi. Objectives: Oak is a common host tree for ambrosia beetles (Coleoptera: Curculionidae: Scolytinae), which have independently evolved a nutritional mutualism with fungi. We suspected that ambrosia beetles might have specific habitat preferences that are different from those of other saproxylic beetles and that reflect the specific habitat preferences of their food, i.e., ambrosia fungi. Methods: We assessed ambrosia beetle abundance with ethanol-lured traps in five old-growth oak dominated forests and five managed oak dominated forests (one trap per forest) during the vegetation period in 2020. We determined whether ambrosia beetle abundance and species richness depend on forest type (managed vs. unmanaged), degree of canopy closure, abundance of oak trees, abundance of coarse deadwood, and abundance of dead oak branches. Results: In total, 4137 individuals of six species of ambrosia beetles associated with oaks were captured. The native ambrosia beetle Anisandrus dispar represented the majority of trapped ambrosia bark beetles. A. dispar along with another ambrosia beetle, Xyleborinus saxesenii, represented 99% of all captured beetles. Conclusions: In addition to canopy closure, the abundance of oak trees and the abundance of dead oak branches were significantly associated with ambrosia beetle abundance and species richness. The abundance of A. dispar was mainly correlated with dead oak branch abundance and the degree of canopy closure, whereas the abundances of X. saxesenii and of the invasive species Xyleborinus attenuatus and Cyclorhipidion bodoanum were mainly correlated with the net area occupied by oak trees.

Reliability of sagittal suture maturation for age-at-death prediction assessed by means of machine learning techniques

The sagittal suture (SS) is one of the major calvarial sutures and is used as an age-at-death indicator in forensic and bioarchaeological expertise. This study aimed to investigate whether the degree of SS closure could be used for a reliable age-at-death prediction. For this purpose we investigated the degree of SS closure in depth and applied symbolic and sub-symbolic machine learning algorithms designed to solve regression tasks.

The role of target closure in detachment in Magnum-PSI

A cylindrical target with a high degree of closure was exposed to ITER divertor-relevant plasmas with typical electron temperatures of 2 eV, electron densities of 5⋅1020 m−3, and heat fluxes up to 20 MWm−2 in the linear device Magnum-PSI. By terminating the plasma in an unpumped closed volume, neutral pressures were enhanced from about 0.5 to 20 Pa without any increase in the neutral flux returning to the plasma. Such pressures were sustained largely by the pressure exerted by the incoming plasma. By means of hydrogen gas injection, internal neutral pressures of up to 40 Pa were reached during plasma exposure. We find that at these high neutral pressures, a < 1 eV recombination front forms and expands from the back of the cylinder, so that downstream density drops dramatically. Furthermore, in these scenarios, heat deposition to the back plate vanishes and is redirected to the upstream part of the cylinder and to hot neutrals, which can carry 50% of the plasma input power. A power balance analysis reveals that even without additional gas puffing, only about 10% of the incoming heat load reaches the back plate for the 20 MWm−2 plasma. These results demonstrate the important role of closed target configurations and local gas puffing in mitigating plasma heat loads and indicate that the gained experience should be taken into account in next-generation divertor designs.

Effect of Closure Characteristics of Annular Jet Mixed Zone on Inspiratory Performance and Bubble System

In the flotation process, gas-liquid properties and the bubble system greatly influence bubble mineralization. In order to clarify how the mechanism applies to the closure characteristics of an annular jet mixed flow zone on the inspiratory performance and the bubble system, different degrees of closure on the velocity field and gas-liquid ratio in the mixed flow zone were investigated using numerical simulation. The variations in the characteristics of bubble size distribution, rising velocity, and gas content under different closure levels were measured with a high-speed dynamic camera technology. The results confirmed that when the closure degrees of the mixed flow zone improved, the inlet jet could gradually overcome the static pressure outside the nozzle effectively. It formed a gas-liquid mixing zone with high turbulence first, and a large pressure difference at the gas-liquid junction second. This helped to increase the inspiratory capacity. At the same time, the gas-liquid ratio rose gradually under conditions of constant flow. When the nozzle outlet was completely closed, the gas-liquid ratio gradually stabilized. For the bubble distribution system, an enhancement in the closure degrees can effectively reduce the bubble size, and subsequently, the bubble size distribution became more uniform. Due to the improved gas-liquid shear mixing, the aspect ratio of the bubbles can be effectively changed, consequently reducing the bubble rising speed and increasing the gas content and bubble surface area flux of the liquid.