Head Zone Research Articles

Base-metal exploration by using remote sensing, geological, geophysical, and geochemical datasets with clues from ancient mining: A comprehensive review on Aravalli-Delhi Fold Belt, Rajasthan, India

Base metal deposits are present in different continents with evidences of their mining activities during ancient times as mentioned in the historical literature. Aravalli – Delhi Fold Belt (ADFB) in Rajasthan, India is having numerous base metal prospects where ancient mining signages are recorded. Modern-day mining has commenced taking clues from these evidences. Present-day techniques such as remote sensing, geological mapping, geophysical survey, geochemical survey, and exploration/drilling are utilized for the identification of surficial ancient mining features and identification of the mineralized zones. These techniques utilize their unique criteria to get an idea of the mineral association. The integration of all the unique characteristics of modern techniques with the help of weighted overlay analysis, fuzzy logic, multi-criteria overlay analysis, etc. helps to identify the mineral potential zones from the ancient working sites. Their integrated results provide the surficial as well as sub-surficial information of the region that gives a better revelation about the region and helps in decision-making towards the mineralization status of the region. World-over surficial ancient features have been recorded in exploratory sites for base metals, and the case histories where integrated techniques were used for mineral exploration are discussed. Zawar – Dungarpur belt also has the potential for base metals therefore, the boolean approach, weighted overlay, and multi-criteria overlay analysis were performed using remote sensing, structural, and geochemical datasets. The integrated results showed that the head zone and southern broader part near Keekawat have the potential for base metals.

The relationship between humeral head angulation and bone void within the humeral head in proximal humerus fractures

BackgroundThe variability of humeral head angulation in proximal humerus fractures (PHFs) is a noteworthy observation. The purpose of this study was to investigate the potential association between humeral head angulation and bone void within the humeral head in PHFs. MethodsWe used the reconstruction function in Mimics software to generate three-dimensional models of fractures. Bony landmarks were employed to accurately define the calcar and humeral head zone. Boolean subtraction was performed to calculate the volume of head bone void. ResultsThe cohort consisted of 60 (74.1 %) varus, 21 (25.9 %) valgus, and 23 (22.1 %) neutral angulated PHFs. The mean percentage of humeral head bone void was 38.5 ± 17.8 in varus, 36.3 ± 15.7 in valgus, and 30.1 ± 10.6 in neutral angulated PHFs. A significant difference was observed between the varus and neutral groups (P = 0.035). In addition, an analysis of humeral head bone void was conducted among patients aged over 65 years old, revealing a mean percentage of 42.7 ± 16.4 in varus (27 cases), 34.8 ± 14.5 in valgus (13 cases), and 28.1 ± 11.8 in neutral (8 cases) angulated PHFs. The difference between the varus and neutral groups was also significant (P = 0.023). ConclusionAll types of angulation patterns exhibited humeral head bone void to some extent, with the varus-displaced PHFs demonstrating more obvious defects in comparison to the neutral angulated type.

Study on Impeller Optimization and Operation Method of Variable Speed Centrifugal Pump with Large Flow and Wide Head Variation

The benefits of variable speed centrifugal pumps include high stability, a broad operating range, and adjustable input power. In water distribution systems, the pump units are increasingly using variable speed technology. The energy-saving features and operational stability of the pump station are directly impacted by the hydraulic performance and the operation strategy. In this study, CFD numerical analysis and model tests were adopted to design and evaluate the hydraulic performance of the variable speed centrifugal pump with large flow and wide head variation in Liyuzhou Pump Station. Under the premise of ensuring the wide head variation, the optimized centrifugal pump met the requirements of hump margin and efficiency in the high head zone and the cavitation margin in the low head zone. The test results demonstrated that the operational range of the variable speed centrifugal pump was successfully widened by reasonable hydraulic parameters selection and impeller optimization. The safe and efficient operational range of the variable speed unit was determined by means of taking the performance requirements of the pump’s maximum input shaft power, cavitation characteristics and pressure fluctuation into consideration. The scientific and reasonable operational path to meet the various operation needs was also investigated and determined for the pump station’s actual operation needs. A high efficiency, safe operation, and a simplified control logic were achieved by using the operational path, which makes it a reasonable potential guide for hydraulic design and operational optimization of variable speed centrifugal pumps with large flow and wide head range.

Developing a Computational Fluid Dynamics-Finite Element Method Model to Analyze Thermal-Mechanical Stresses in a Heavy-Duty Medium-Speed Diesel Engine Piston During Warm-Up

Abstract Pistons play a vital role in internal combustion engines, affecting both performance and reliability, and are subjected to intense thermal-mechanical loads that have become more challenging due to improved engine efficiency and power. This study examines the thermal and mechanical stress experienced by a piston in a heavy-duty medium-speed diesel engine during warm-up. The heavy-duty diesel engines are typically used in heavy trucks, locomotives, and ships. A combination of computational fluid dynamics, finite element method, and matlab was used to consider factors such as oil temperature and flowrate, coolant temperature, component temperature, and boundary conditions during engine transient conditions. The results highlight the significant variations in the thermal and mechanical stress on the piston, particularly in the piston head under different warming-up conditions. It is noted that the variation in oil temperature is a crucial factor affecting the thermal stress on the piston. Low oil temperature can result in reduced heat exchange coefficient and inadequate cooling of the piston due to low flowrate of the cooling oil. During engine warm-up, both thermal and combined stresses reach maximum values and then decrease when the engine reaches stable operating conditions. By selecting appropriate warming-up modes, the quality of the warm-up process and the strength and longevity of the engine could be improved. This study also provides useful insights for technicians to prevent critical conditions that may damage the piston and reduce its strength and lifespan.

Correlations of confectionary seed traits in different head zones sunflower

Abstract It is proposed to study the qualities of sunflower seeds in three zones of location in the head. Moderate negative correlations of the sign of the number of lateral heads (branching) in sunflower lines from the mass of 1000 seeds, the number of rows, seeds in a row, the total number of seeds and the diameter of the head were established (r = −0.5 to −0.53* on the Chedokk scale). The dependence of the number of seeds in the head on its size was confirmed (r = 0.83). In particular, we obtained a high positive correlation between the signs of the number of rows in the head and the number of seeds in the row with the size of the head (0.71 and 0.72). It was established that the mass of 1000 seeds of the first tier has correlations with the number of seeds in a row and the number of rows (r = 0.32 and 0.39), which are attributed only to the group of noticeable ones. This indicates the possibility of combining in one plant a large number and size of seeds in the head. It was found that changes in the size and weight of the seeds in the head by zone occur in hybrids and lines gradually, while the variety shows only a slight decrease in the size and weight of the seeds in the third zone. The largest quantity and the best confectionary quality of seeds was provided by the Zaporizhzhya Confectionery variety. In hybrids, the output of seeds weighing 90–80 g from one head reached only 1000 pieces. The potential to increase the number of seeds in heads in hybrids is present, but the size of the seeds is critical. With the available average weight of 1000 seeds: 90 g in the best maternal line and 70 in the best paternal line, the hybrids only approached the 100 g mark.

Henry Head (1861-1940) and his importance for neurology

Nowadays, Henry Head is best known for his Head zones. The concept was understood very differently by Head in comparison to what current medical books falsely describe them to be. In reality, there is no direct relationship between one particular skin zone and one single organ. It is certain that the drawings considered depictions of the Head zones in today's medical textbooks were actually not created by Head. From aneurological point of view, Head is important for two reasons: his self-experiment in 1909 to damage one of his own peripheral nerves followed by regeneration was heroic. It has helped generations of neurologists to have a better understanding of the pathophysiology of peripheral nerve damage and thus make a better assessment of the prognosis of such injuries. Head's second contribution pertains to the radicular organization at the level of the spinal cord. The pathophysiology of herpes zoster radiculitis enabled him to develop the concept of the dermatomes on the basis of preliminary work around 1900. Henry Head's contribution was the systematic compilation of the existing publications of the time and amendment of his own cases. As he was the most important neurologist at that time, at least in the English speaking world, and was well connected with people in the German neurology community, it was probably easy for him to make his dermatome maps well known. In retrospect, Head was less successful in neuropsychology with holistic concepts for higher cognitive functions which were in vogue during his lifetime. His late work on aphasia is now considered refuted. Head's criticism of the strict localization was well in syncronization with the zeitgeist of the early twentieth century. Establishing the fact that Broca's aphasia and Wernicke's aphasia are not easily diagnostically distinguishable from each other was more an achievement of subsequent generations of neurologists and neuropsychologists as well as technical advances.

Evolution characteristics of mid‐channel bars with a typical high/low bank structure in the Middle Yangtze River

AbstractAdjustments in mid‐channel bars (MCBs) often influence the stability of channel regime and the safety of river navigation in anabranching reaches. This study aims to investigate the evolution characteristics of the low and high parts of MCBs (L‐MCBs and H‐MCBs) in the Middle Yangtze River (MYR) and reveal the main factors influencing the deformation of these two components. Results show that the total exposed area of L‐MCBs decreased from 305 to 288 km2 in 2003–2019, whereas the H‐MCBs remained relatively stable. Taking the Nanyang bar with a typical high/low bank structure as an example, the deformation of the L‐MCB mainly occurred in the head zone, while the deformation of the H‐MCB was characterised by bank retreat in the tail zone and floodplain deposition on the top of the H‐MCB. In terms of influencing factors, the impacts of the altered flow–sediment conditions and the MCB's properties (soil composition and morphology characteristics) on the Nanyang bar deformation were investigated. On the one hand, the reduction in sediment concentration was the most direct factor causing the shrinkage of L‐MCBs, and the decrease in flood occurrence frequency made the deformation of H‐MCB less significant. On the other hand, the soil composition of the L‐MCB primarily consisted of fine sand with weak erosion resistance, while the large content of cohesive sediment made the H‐MCB difficult to be eroded by overbank flows; moreover, the riverbank of the H‐MCB in the bar‐tail zone was much steeper than that in the bar‐head zone, causing the deformation of the high part to mainly occur in the tail zone. Furthermore, the deformation of the high part was simulated using a bank erosion model at section scale, and the calculated safety factors of riverbank at a typical cross‐section show that the riverbank of the H‐MCB was the most unstable during the receding period.

The microvascular bed of the skin of lower limbs in patients with intermittent lameness and coronary heart disease as a possible model of their myocardial microcirculation

Purpose: to assess possibility to extrapolate findings of skin microvascular bed examination in lower extremities with laser Doppler flowmetry in patients with obliterating atherosclerosis as a model of their myocardial microcirculation in coronary heart disease.Material and methods. Males with angiographically confirmed coronary heart disease (n = 70) and obliterating atherosclerosis in lower limbarteries (n = 74) were taken in the study. Microcirculation of the skin in the left forearm in the Zakharyin – Head zone in patients with coronaryheart disease and skin microcirculation in the foot of affected limb in patients with obliterating atherosclerosis of arteries of lower extremities were examined with laser Doppler flowmetry. The basal blood flow, amplitude-frequency spectrum of its oscillations, myogenic, neurogenic vascular tone and occlusion parameters were assessed as well. Comparison groups included 50 practically healthy males for the patients with coronary heart disease and 20 males – for the patients with obliterating atherosclerosis of arteries of lower extremities. Patients were examinedat the initial stage and in 2–3 weeks after endovascular restoration of blood flow in the myocardium and lower limbs.Results and discussion. At the initial research stage, the microcirculation picture in patients with coronary heart disease and obliterating ath-erosclerosis in lower extremities differed from that of healthy individuals by shifts covering all links of the microvascular bed and characterizedby constriction of the precapillary segment, a statistically significant decrease in median values of capillary blood flow by 17.5 and 43.1 %,microvascular blood flow reserve – by 11.2 and 31.0 %, as well as by the increase in arteriolovenular blood bypass – by 10.3 and 70.8 %,respectively. After the restoration of blood flow in lower extremities in patients with obliterating atherosclerosis, muscular pain disappeared,and the ankle-shoulder index got normalized. At the same time, one could observe a statistically significant increase in the capillary blood flow(+13.6 %), the increase of reserve potential in microvascular bed (+20.6 %) with the simultaneous decrease of vascular tone in the precapillarysegment (–15.1 %) and of the blood bypass index (–25.0 %). Better clinical picture after coronary angioplasty in patients with coronary heart disease was accompanied with a similar and unidirectional tendency to positive changes in the microvascular bed.Conclusion. As far as etiopathogenetic mechanisms and clinical manifestations of coronary heart disease and obliterating atherosclerosis in arteries of lower extremities have much in common and microcirculatory shifts in forearm and foot skin in these patients before and after angioplasty are unidirectional, all these allow to suggest that one can see similar changes in the myocardium microcirculatory system in patients with coronary heart disease. Thus, it opens possibilities to have a targeted medicamentous impact at the microvascular level.

Experimental and Numerical Study on the Ablation Analysis of a Pintle Injector for GOX/GCH4 Rocket Engines

In the present study, the ablation of a pintle injector on a 500N GOX/GCH4 rocket engine under different working conditions is studied experimentally and numerically. The temperature of the pintle tip and the combustion gas in the head zone was measured in a series of experiments by the thermocouples. Moreover, a three-dimensional model was established to simulate combustion and heat transfer concurrently and analyze the ablation state of the pintle injectors. The obtained results indicate that under a low chamber pressure (pc=0.25 MPa) and an increasing O/F ratio from 0.8 to 2, the tip temperature declines first, and then rises. At the designed working condition (pc=1.05 MPa and O/F = 3.2), the pintle tip suffered serious ablation, and the microstructure analysis indicates that the ablation failure of the stainless steel pintle tip originates from chromium precipitation. This phenomenon is especially more pronounced when the temperature exceeds 1273 K, which makes the structure fragile and vulnerable. This article helps to provide an understanding of the ablation failure of the pintle injectors, and the established model is capable of giving a prediction on the ablation status of the pintle tips consistent with the experiment.

In vitro and in vivo degradation behavior of Mg-0.45Zn-0.45Ca (ZX00) screws for orthopedic applications

Magnesium (Mg) alloys have become a potential material for orthopedic implants due to their unnecessary implant removal, biocompatibility, and mechanical integrity until fracture healing. This study examined the in vitro and in vivo degradation of an Mg fixation screw composed of Mg-0.45Zn-0.45Ca (ZX00, in wt.%). With ZX00 human-sized implants, in vitro immersion tests up to 28 days under physiological conditions, along with electrochemical measurements were performed for the first time. In addition, ZX00 screws were implanted in the diaphysis of sheep for 6, 12, and 24 weeks to assess the degradation and biocompatibility of the screws in vivo. Using scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX), micro-computed tomography (μCT), X-ray photoelectron spectroscopy (XPS), and histology, the surface and cross-sectional morphologies of the corrosion layers formed, as well as the bone-corrosion-layer-implant interfaces, were analyzed. Our findings from in vivo testing demonstrated that ZX00 alloy promotes bone healing and the formation of new bone in direct contact with the corrosion products. In addition, the same elemental composition of corrosion products was observed for in vitro and in vivo experiments; however, their elemental distribution and thicknesses differ depending on the implant location. Our findings suggest that the corrosion resistance was microstructure-dependent. The head zone was the least corrosion-resistant, indicating that the production procedure could impact the corrosion performance of the implant. In spite of this, the formation of new bone and no adverse effects on the surrounding tissues demonstrated that the ZX00 is a suitable Mg-based alloy for temporary bone implants.

Escape Survival and Scale Damage Assessment of Red Mullet (Mullus barbatus Linnaeus, 1758) during Bottom Trawling in the Central Mediterranean Sea.

Stock assessments routinely evaluate the status of commercially harvested species, but seldom account for the possible mortality of released or escaping fish. This study presents a method for estimating the escape survival of the red mullet (Mullus barbatus) from demersal trawling in the Central Mediterranean Sea. Fish escaping from the trawl codend were collected in a detachable cage, which was lined to reduce water flow and protect the sampled fish from further fatigue and injury. Control fish (from an open codend) showed high survival, 94% (87-97%, 95% Confidence Interval), and minimal injuries, while fish escaping through codend meshes had significantly increased injuries and reduced survival, 63% (55-70%). During 7 days of captive monitoring, treatment group mortality was highest in the first 24 h and ceased for both groups within 48 h. Conflicting length-related mortality was observed, where larger treatment fish had a higher probability of dying, while the opposite was observed in the controls. Analysis showed that treatment fish were significantly more injured than control fish, with treatment fish predominantly injured in the head zone. In conclusion, this improved methodology should be repeated to provide accurate escape mortality estimates for the improved stock assessment of the red mullet in the Central Mediterranean.

Improving Cephalad Lag Screw Placement in the Femoral Head During Cephalomedullary Nailing Using a Novel Augmented Reality System.

To measure the effect of a novel augmented reality software designed to aid in lag screw placement into the femoral head for cephalomedullary nails. Retrospective cohort study. Single Level I trauma center. Between November 2017 and December 2020, 114 consecutive patients with a hip fracture that underwent repair with a cephalomedullary nail by one of 2 orthopaedic trauma surgeons were reviewed. Fracture classifications included OTA/AO 31-A1, 31-A2, 31-A3, and 31-B3. The first 57 patients underwent fracture repair without the software (control) and the subsequent 57 patients underwent repair with use of the augmented reality software (AR). Tip apex distance (TAD) and femoral head zone (AP: superior, center, inferior; Lateral: anterior, center, posterior) were measured using standardized techniques. The mean TAD was lower for the AR versus control cohort (10.7 ± 2.9 mm vs. 15.4 ± 3.8 mm; P < 0.001). TAD <10 mm for AR versus control: 25 (43.9%) versus 3 (5.3%), P < 0.001. TAD <15 mm for AR versus control: 50 (87.7%) versus 44 (77.2%), P < 0.001. On the AP view, center position was achieved in 50.9% versus 7.0% of cases for the AR versus control cohort, respectively. On the lateral view, center position was achieved in 68.4% versus 12.3% of cases for the AR versus control cohort, respectively. This study suggests that use of the novel augmented reality software for assistance in lag screw positioning within the femoral head improves overall TAD and ability to achieve the center-center position. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Evolution process and mechanism of mid-channel bars composed of different bed materials in the Upper Jingjiang Reach after the Three Gorges Project operation

三峡及上游梯级水库群运用后,大坝下游江心洲以冲刷为主,直接影响分汊河段河势条件及航道边界的稳定性。本文采用卫星遥感影像、实测水沙及固定断面床沙级配等资料,分析上荆江枝江、沙市河段中不同河床组成江心洲的演变过程及其机理。结果表明:①三峡水库蓄水后(2003-2019年),沙市段沙质江心洲较枝江段卵石夹沙质江心洲萎缩更为显著,出露面积的减幅分别达31%和24%。②以关洲和金城洲分别代表卵石夹沙质和沙质江心洲,三峡工程运用后关洲洲头形态较为稳定,受无序采砂的影响其沙质组成的洲尾面积显著减小,而金城洲面积萎缩程度更大。③床沙组成对江心洲冲刷程度差异具有重要影响,关洲洲头较金城洲抗冲性更强,与其床沙在年内达到起动条件的数量更少、时长更短有关;建立了江心洲面积与水流冲刷强度及相对水深的定量关系,该关系能综合考虑水沙变化与床沙组成调整的影响,能更好地反演近期江心洲的面积变化特点。;After the operation of the Three Gorges cascade reservoirs (TGP), the mid-channel bars (MCBs) downstream of the dam were generally scoured and shrank, which directly affects the river regime in ana-branching reaches and the stability of the navigation channel boundaries. The morphological evolution processes and mechanisms of MCBs in the Zhijiang (ZJ) and Shashi (SS) sub-reaches of the Upper Jingjiang Reach were analyzed, using the remote sensing images, the hydrological data and the measured riverbed compositions. The results indicate that: (i) During the post-TGP period (2003-2019), the sandy MCBs in the SS subreach shrank more significantly than the one in the ZJ subreach. The total exposed area of the former decreased by 31%, while the latter decreased by 24%; (ii) Guanzhou (GZ) and Jinchengzhou (JCZ) were taken as the representative sandy-gravel and sandy MCBs, respectively. During the post-TGP period, the head zone of the GZ MCB was relatively stable, and the reduced area was mainly in the bar-tail zone due to the illegal sand mining, while the JCZ MCB had a more obvious erosion trend; (iii) The bed-material composition had an important influence on the erosion degree of MCBs. The GZ MCB had a stronger anti-erosion capacity than the JCZ MCB, which was related to the less amount and duration of bed material that can reach the incipient condition in a hydrological year. Moreover, different empirical relationships were developed between the exposed area of MCB, fluvial scour intensity, and relative water depth. It is found that comprehensive consideration of the effects of flow-sediment condition and bed-material composition adjustment can better explain the recent variations in the exposed areas of MCBs.

Spatiotemporal Variation and Driving Factors of Water Supply Services in the Three Gorges Reservoir Area of China Based on Supply-Demand Balance

Water supply services (WSSs) are critical to human survival and development. The Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model enables an integrated, dynamic, and visual assessment of ecosystem services at different scales. In addition, Geodetector is an effective tool for identifying the main driving factors of spatial heterogeneity of ecosystem services. Therefore, this article takes the Three Gorges Reservoir Area (TGRA), the most prominent strategic reserve of freshwater resources in China, as the study area and uses the InVEST model to simulate the spatiotemporal heterogeneity of the supply-demand balance of WSSs and freshwater security patterns in 2005, 2010, 2015, and 2018, and explores the key driving factors of freshwater security index (FSI) with Geodetector. The total supply of WSSs in the TGRA decreased by 1.05% overall between 2005 and 2018, with the head and tail areas being low-value regions for water yield and the central part of the belly areas being high-value regions for water yield. The total demand for WSSs in the TGRA increased by 9.1%, with the tail zones and the central part of the belly zones being the high water consumption areas. In contrast, the head zones are of low water consumption. The multi-year average FSI of the TGRA is 0.12, 0.1, 0.21, and 0.16, showing an upward trend. The key ecological function areas in the TGRA are high-value FSI regions, while the tail zones in the key development areas are low-value FSI regions. Industrial water consumption significantly impacts FSI, with a multi-year average q value of 0.82. Meanwhile, the q value of industrial and domestic water consumption on FSI in 2018 increased by 43.54% and 30%, respectively, compared with 2005. This study analyzes the spatiotemporal variation of WSSs and detects the drivers in the natural-economic-social perspective and innovation in ecosystem services research. The study results can guide water resource security management in other large reservoirs or specific reservoir areas.

Selection of the rational geometry of specimen for compression test

The object of study in this article is the conditions during the compression test. The subject matter is the models that simulate the physical processes during the compression test. The goal is to obtain models, which allow obtaining real information about stress-strain dependence during compression. The tasks to solve are to develop a three-dimensional computer model of a specimen subjected to compression that geometry allows to avoid the nonuniform distribution of stress-strain state. The upsetting of cylindrical specimens is one of the most commonly used methods for compression tests. However, due to the frictional force on both ends of the specimen, a barreling shape is likely to appear in the middle of the cylinder during the compression process, resulting in inaccurate mechanical properties of the final measured specimens. Therefore, this paper conducts qualitative and quantitative research on the physical parameters that affect the degree of barreling during the upsetting process of cylindrical specimens. The following results were obtained. The Concave End Face (CEF)-Upsetting and Headed Specimen (HS)-Upsetting methods have a significant effect on reducing the barreling degree. The smallest difference in the barreling degree is almost close to 101.8 % that appears in the CEF-Upsetting. Further analysis shows that the above two methods have similar principles for reducing the barreling degree, and both reduce the barreling degree in the middle by increasing the deformation of the workpiece ends. Then, the influence of the deformation of the workpiece head zone on the deformation of the non-end (gauge length) zone is analyzed. The rounded corners of the transition zone between the workpiece end zone and the non-end zones of HS-Upsetting have a great influence on the generation of forming defects. The end face groove size of CEF-Upsetting has a significant effect on the barreling degree after upsetting. Under the same other conditions, the barreling degree is the smallest when the ratio of the concave depth (a/D) is 0.12, when the ratio of the concave diameter(Dc/D) doesn’t exceed 0.6, the smaller the ratio of the concave diameter(Dc/D), the smaller the barreling degree. Finally, through the design of the orthogonal test, the functional relationship between the barreling degree and the dimension parameters of the workpiece ends zone is established. Conclusions: It doesn’t prove the feasibility of barreling-less upsetting only, but also provides theoretical support for actual production in the future.

Study of the airflow and vortex distributions in a long-narrow enclosed space

In an aircraft cabin, there is a great influence of indoor air quality on the physiological and mental health of passengers. To promote indoor air quality, this research performed experiments and CFD to analyze the flow field characteristics in an aircraft cabin. This study investigated the airflow characteristics of a full-scale cabin using a scaled model. The experimental results indicated that the supply air jet easily formed vortex structures around the chest and head zones of the occupants. The airflow was unstable at the cross-section and longitudinal scales. The Transition SST (4eqn) model could accurately simulate the flow field, and the supply air jet alternatively controlled the cross-section flow field, induced the unstable phenomena spatially and temporally. The vortex structures around the occupants produced and disappeared in both time and space. It showed the instability of the airflow in the aircraft cabin. And this instability of the airflow could induce the dissipation of vortex structures in the time series. This enhanced the unstable distribution of vortex structures. This study further clarifies the distribution of the velocity field and provides references for the futural design of airflow in aircraft cabins.

An experimental and numerical study on the crush responses and energy absorption characteristics of single- and bi-layer cups under low-velocity impact

Observations on the crush responses and the energy absorption characteristics of single- and bi-layer deep-drawn cups subjected to experimental axial impact loading are presented in this manuscript. Bi-layer plates composed of aluminum and stainless steel alloys were fabricated by joining with adhesive and formed by a deep drawing process to produce the final cup shape. Impact testing was performed using a custom-built drop-tower system with a mass of 45.45 kg and impact velocities ranging from 2.8 m/s to 4.5 m/s. Various material and geometric parameters for the bi- and single-layer cups were considered in the study. Numerical simulations were conducted to investigate the deformation mechanisms and crushing behavior of the combined shells. Furthermore, based on the polynomial response surface method and using non-domain sorting genetic algorithm II, some multi-objective optimizations were performed on specific energy absorption, stroke efficiency, specific total efficiency, and initial peak load. Experimental and numerical results illustrated that the deformation of the bi-layer cups was different from the single-layer cups, especially in the head zone. Moreover, the specific total efficiency for specimens having a diameter of 55 mm and 65 mm were approximately 35% and 55% less than cups with a diameter of 45mm, respectively. It was found that the layer order of the bi-layer cup influences the energy absorption capacities of the specimen. Specifically, cups with steel as the outer layer experienced crush force efficiency and total efficiency of 6% and 5% higher than those with an aluminum outer layer, respectively.

Розробка раціональних технологічних параметрів обігріву коксової батареї з трамбуванням вугільної шихти.

DEVELOPMENT OF RATIONAL TECHNOLOGICAL PARAMETERS FOR HEATING OF A COKE BATTERY WITH A STAMPED CHARGING OF COALS © V.I. Goncharov, I.I. Sikan, Ya.I. Dyachuk, N.V. Mukina (Coke production of PJSC «ArcelorMittal Kryvyi Rih», 50095, Dnipropetrovsk region, Kryvyi Rih, Kryvorizhstal str., 1, Ukraine), I.V. Shulga, PhD in technical sciences (State Enterprise "Ukrainian State Research Coal Chemical Institute (UHIN)", 61023, Kharkov, Vesnina st., 7, Ukraine) The article is devoted to the introduction at the PJSC «ArcelorMittal Kryvyi Rih» coke plant of a promising technology for compaction of a coal charge, which allows obtaining blast furnace coke of high mechanical and "hot" strength from charges characterized by an increased content of lean components of various stages of metamorphism. Under the present circumstances, this is of great importance for increasing the economic indicators of the production of blast furnace coke and the operation of blast furnaces. The start-up of coke oven battery No. 6, designed for the application of this technology, necessitated the determination of rational technological parameters of heating: the temperature level in the control verticals and the location of the burners for supplying coke oven gas in the vertical along the heating wall. The article presents the calculations, the results of which confirm the expediency of rationalizing the actual starting (design) distribution of burners on coke oven battery No. 6. First of all, attention is drawn to the insufficient diameters of the holes in the burners for the extreme and pre-extreme verticals. This, according to the authors, caused underheating of the head zones and resin spills, which were observed during start-up operations on the battery. The replacement of burners at the edges of the walls by large diameters, carried out by the personnel of the coke shop of the coke plant PJSC “ArcelorMittal Kryvyi Rih” and LLC “Koksokhimstanciya”, combined with the full opening of the recirculation windows in these zones, improved the heating of the charge and significantly reduced the intensity of spills. The experience gained was taken into account when locating the control devices at coke oven battery No. 5, which was put into operation later. The article also formulates recommendations for adjusting the temperature regime of coking, depending on the grade and component composition, as well as the technological properties of coal charges. Keywords: coke oven battery, stumping of coal charge, temperature in control verticals, location of burners along the length of the heating wall. Corresponding author Ya.I. Dyachuk, е-mail: Yaroslav.Dyachuk@arcelormittal.com

Application of three-dimensional detailed geometry to simulation of melt progression in an intricate BWR lower head

This study analyzes melt progression with core degradation in the core and lower head of a boiling water reactor using a detailed simulation geometry of an in-house three-dimensional simulation code. Since the Fukushima Daiichi nuclear power plant accident of Tokyo Electric Power Company Holdings (TEPCO) in 2011, the condition of the lower head following melt progression has been a topic of interest worldwide. By taking advantage of the unique characteristics of the three-dimensional simulation code, we focus on achieving a more detailed simulation of the reactor pressure vessel in view of future Fukushima decommissioning processes. Molten corium forms in the core and progresses towards the lower head. When the corium reaches water remaining there, it is fragmented and forms fuel debris on the bottom of lower head. Hence evaluating molten corium breakup with water in the lower head is essential for the coolability of fuel debris and the integrity of the lower head to prevent the release of a large amount of radioactive isotopes. To simulate melt progression together with core degradation effectively, we focused on the development of the detailed simulation geometry comprising the core, the core support plate, and the lower head zones as well as the simplified pedestal of the primary containment vessel. The analysis capabilities due to the detailed simulation geometry were preliminarily evaluated under hypothetical conditions (i) melt progression from the core to the pedestal of primary containment vessel, (ii) failure of the core support plate zone due to molten corium, (iii) water pool behavior in the lower head, (iv) the relocation paths of molten materials via the control rod guide tube/control rod drive housing and instrument guide tube, and (v) mixing behavior of molten corium resulting from different fuel assemblies.

Displacements of an Active Moderately Rapid Landslide—A Dataset Retrieved by Continuous GNSS Arrays

This paper describes a dataset of continuous GNSS positioning solutions referring to slope movements in the Ca’ Lita landslide (Northern Apennines, Italy). The dataset covers the period from 24 March 2016 to 17 July 2019 and includes time-series of the daily position of three GNSS rovers located in different parts of the landslide: head zone, upper track zone, and lower track zone. Two different types of continuous GNSS arrays have been used: one is based on high-end Leica geodetic receivers, and the other is based on low-cost effective Emlid receivers. Displacements captured in the dataset are up to more than a hundred meters and are characterized by prolonged phases of slow movement and moderately rapid acceleration phases. The data presented in this contribution were used to underline slope processes and validate displacements retrieved by the application of digital image correlation to a stack of a satellite images.