Higher Height Research Articles

Theoretical Research and Shaking Table Test on Nominal Aspect Ratio of the Isolated Step-Terrace Structure

With the installation of rubber isolation bearings in the upper and lower ground layers, an isolated step-terrace structure was created. Considering the ultimate bearing capacity of the rubber bearing under tension as the critical condition, a comprehensive framework was established to evaluate the overturning failure mechanisms present in isolated step-terrace structures. The bound of nominal aspect ratio was identified as the principal control index within this framework, which incorporates critical parameters such as height ratio (α), width ratio (β), vertical tensile stiffness to compressive stiffness ratio (γ), seismic coefficient (k), and nominal vertical compressive stress (σ0) to provide a thorough analysis of the structural responses and potential failure scenarios. In order to further investigate this matter, a scaled model of an isolated step-terrace concrete frame structure featuring two dropped layers and a single span within an 8° seismic fortification zone was meticulously crafted at a 1:10 similarity ratio. Subsequently, a series of shaking table tests were conducted to analyze the structural response under seismic excitation. The findings indicate that: utilizing the bound of nominal aspect ratio as a metric to gauge the anti-overturning capacity of isolated step-terrace structures is a justified approach. In instances where the height ratio remains constant, the bound of nominal aspect ratio for both positive and negative overturning trended upward with an increase in the width ratio. Notably, the bound of nominal aspect ratio for positive overturning consistently registered lower values compared to that of the negative overturning, underscoring the heightened susceptibility of step-terrace structures to positive overturning. Moreover, in scenarios characterized by higher height and width ratios, the structural integrity remained unscathed by any overturning effects arising from insufficient tensile strength in rubber bearings. Furthermore, the bound of nominal aspect ratio exhibited an ascending trend as the seismic coefficient, nominal vertical compressive stress, and vertical tensile stiffness to compressive stiffness ratio decreased. The outcomes derived from the shaking table test not only confirm the impressive seismic performance of the structure, but also, by closely examining the instantaneous stress variations within the upper and lower isolation layers of the model, substantiate the existence of a positive overturning hazard in scenarios marked by higher seismic coefficients (k). This observation aligns seamlessly with the theoretical projections, thereby substantiating the efficacy of the structural overturning failure theory through direct empirical verification.

Over 600 V Lateral AlN-on-AlN Schottky Barrier Diodes with Ultra-Low Ideality Factor

This letter reports the demonstration of lateral AlN Schottky barrier diodes (SBDs) on single-crystal AlN substrates by metalorganic CVD (MOCVD) with an ultra-low ideality factor (η) of 1.65, a high Schottky barrier height of 1.94 eV, a breakdown voltage (BV) of 640 V, and a record high normalized BV by the anode-to-cathode distance. The device current was dominated by thermionic emission, while most previously reported AlN SBDs suffered from defect-induced current with higher η (>4). This work represents a significant step towards high-performance ultra-wide bandgap AlN-based high-voltage and high-power devices.

Impacts of synoptic weather patterns on Hefei's ozone in warm season and analysis of transport pathways during extreme pollution events

Extreme ozone pollution events (EOPEs) are associated with synoptic weather patterns (SWPs) and pose severe health and ecological risks. However, a systematic investigation of the meteorological causes, transport pathways, and source contributions to historical EOPEs is still lacking. In this paper, the K-means clustering method is applied to identify six dominant SWPs during the warm season in the Yangtze River Delta (YRD) region from 2016 to 2022. It provides an integrated analysis of the meteorological factors affecting ozone pollution in Hefei under different SWPs. Using the WRF-FLEXPART model, the transport pathways (TPPs) and geographical sources of the near-surface air masses in Hefei during EOPEs are investigated. The results reveal that Hefei experienced the highest ozone concentration (134.77 ± 42.82 µg/m³), exceedance frequency (46 days (23.23 %)), and proportion of EOPEs (21 instances, 47.7 %) under the control of peripheral subsidence of typhoon (Type 5). Regional southeast winds correlated with the ozone pollution in Hefei. During EOPEs, a high boundary layer height, solar radiation, and temperature; low humidity and cloud cover; and pronounced subsidence airflow occurred over Hefei and the broader YRD region. The East-South (E_S) patterns exhibited the highest frequency (28 instances, 65.11 %). Regarding the TPPs and geographical sources of the near-surface air masses during historical EOPEs. The YRD was the main source for land-originating air masses under E_S patterns (50.28 %), with Hefei, southern Anhui, southern Jiangsu, and northern Zhejiang being key contributors. These findings can help improve ozone pollution early warning and control mechanisms at urban and regional scales.

Toleransi Kekeringan Sawi Hijau pada Osmopriming Benih dan Interval Pemberian Air Sampai Kapasitas Lapang

Green mustard (Brassica chinensis L.) is widely cultivated commercially. The problem is that some farmers use self-propagated seeds with simple processing and storage facilities so that the quality of the seeds is not guaranteed and is low. Apart from seed quality, limited water, especially during cultivation in the dry season or on dry land, is also a limiting factor. Low seed quality can be overcome by invigorating seeds using the osmopriming method; water limitations can be overcome by periodically fulfilling field capacity water. This research aimed to measure and analyze the growth response and drought tolerance of green mustard plants in seed osmopriming treatments and setting water intervals to field capacity. The research was carried out at the Experimental Field and Plant Physiology Laboratory, Faculty of Agriculture, IBA University in Palembang, in October-December 2020. The research used a 5x3 Factorial Randomized Block Design, with 3 replications, so there were 45 experimental units. The first factor was seed osmopriming, O1= control (water), O2= CaCl2 1.5% - soaked 4.5 hours, O3=CaCl2 3%-soaked for 4.5 hours, O4=KNO3 1%-soaked for 5 hours, and O5=KNO3 1.5%-soaked for 5 hours. The second factor was watering interval to field capacity, P1= every 24 hours, P2= every 72 hours, and P3= every 120 hours. The research results showed that osmopriming produced values of germination power, vigor index, growth speed, growth simultaneity and maximum seed growth potential of 100%, and with fast and relatively the same germination age of 4.22 to 5.05 days after planting (dap). In plants 14 dap, osmopriming with 1.5% KNO3 and soaking for 5 hours produced plants with the highest height, number of leaves and root length. The interaction of osmopriming with intervals of water supply to field capacity every 24 hours and 72 hours produces plants with the highest height, number of leaves, root length and weight/yield. There was a decrease in plant growth and yield at the interval of providing water to field capacity every 120 hours. The drought tolerance of green mustard is in watering intervals to field capacity every 72 hours.

Poultry Litter Compost and NPK fertilizers Induced Growth and Yield Performance of Boro Rice at Rooftop Farming

The effects of inorganic fertilizers and decomposed poultry litter on the growth and yield performance of boro rice (Oryza sativa L.) were assessed by conducting a pot experiment on the rooftop of a building in Charfasson town, Bhola. The experiment was laid out in a completely randomized design (CRD), having eight treatments with three replications each. Different agronomic parameters were measured at 30-day intervals after sowing of seeds and yield parameters after harvesting. The highest height (82.67 cm) at 90d, number of leaf (37.67) at 120d, longest leaf ( 39.67 cm) at 90d, and length of panicle (27.17 cm), number of grains/panicle (153.33), weight of grain/panicle (3.74 g), fresh weight of grains (62.35 g/pot), dry weight of grain (51.53 g/pot), dry weight of root (13.43 g/pot), rice yield (51.53 g/pot) or (5.67 t ha-1), highest B:C ratio (4.51), respectively, were found in the treatment T7: (3.0 t PL ha-1 + N100P25K90 kg ha-1). The results of treatments T7 and T8 are statistically identical. The overall best growth performance and yield of boro rice were achieved in T7: (3.0 t PL ha-1 + N100P25K90 kg ha-1) treatment on a rooftop farming system on the south coast of Bangladesh. Biodivers. Conserv. Bioresour. Manag. 2024, 10(1): 99-108

ECONOMIC AND BIOLOGICAL EVALUATION OF RADISH HYBRIDS FOR GROWING IN OPEN SOIL IN THE CONDITIONS OF THE CENTRAL PART OF THE RIGHT BANK FOREST-STEPPE

Radish is an early vegetable crop with a very short growing season, widely cultivated worldwide. At the same time, the extensive varietal resources of radishes and the changing environmental conditions compel agroproducers to perform more careful selection of varieties/hybrids to achieve high yields of marketable products. For this purpose, an agro-biological evaluation of eight radish hybrids of different maturity periods was conducted in open-field cultivation. Differences were found in both the duration of phenophases and the growing period of radish plants. The hybrids Stellar and Rockstar were characterized by faster entry into phenological phases, root formation, and maturation, reaching the technical maturity phase on the 25th day. In terms of biometric indicators at the technical maturity phase (BBCH 49), the hybrid Adele stood out, with plants having the highest height (18 cm), leaf rosette width (18 cm), number of leaves per plant (8 pcs), and area (17.6 thousand m2/ha). Over the years of research from 2017 to 2019, which were marked by contrasting weather conditions, the highest yield was obtained from the Adele hybrid, at 26.1–27.3 t/ha, with a 15% advantage over the control and a yield increase of 3.5 t/ha. The hybrids were ranked by yield as follows: Adele > Eliza > Stellar > Rockstar > Rosetta > Roxanne > Donar > Rolex. The highest quality indicators were found in the root crops of the Adele, Stellar, and Rockstar hybrids. Based on the visual assessment of radish root crops, analysis of their linear dimensions, and quality indicators, the hybrids were ranked as follows: Adele > Stellar > Rockstar > Eliza > Rosetta > Roxanne > Donar > Rolex. A strong direct correlation was found between yield and root weight (r=1), as well as between the developmental phases of the plants (seedling emergence, appearance of the first true leaf, growth and development of leaves and roots) and the technical maturity of the root crops (r=0.90–1.00). The number of leaves per plant correlated with plant height (0.97) and the developmental phases of the plants (0.91–0.97). The sugar content in the root crop correlated with the dry matter content and the root diameter (0.92). Based on the agro-biological evaluation of radish hybrids of different maturity groups, it was determined that the most productive hybrids with quality root crops for open-field cultivation are the early-maturing Stellar, the mid-maturing Eliza, and the late-maturing Adele, which are recommended for cultivation in farms of various ownership forms in the central part of the Right-Bank Forest-Steppe.

Fine‐solids removal by foam fractionation in a low‐salinity marine recirculating aquaculture system (RAS)

AbstractObjectiveWe sought to evaluate several methods of operation of a foam fractionator for fine‐solids removal (organic matter < 55 μm) in a commercial‐scale, low‐salinity (11–13‰) recirculating aquaculture system (RAS) for marine finfish production.MethodsThe total suspended solids (TSS) concentrations of the RAS microscreen drum filter inflow and outflow and the foam fractionator outflow were obtained under various foam fractionator operating conditions. The outflow TSS concentration of the drum filter also served as the inflow TSS concentration for the foam fractionator. Sample collection for TSS determination was divided into two categories: particles greater than 55 μm and particles less than 55 μm. The difference between inflow and outflow TSS concentrations was used to determine the removal percentage for each particle class of each unit. Additionally, the volume of foammate produced under operating conditions by the fractionator and the amount of solids contained within the foammate were quantified. Flow through the foam fractionator was also obtained to determine the amount of solids removed per volume of influent water treated.ResultThe influent TSS concentration for the seven different operating conditions evaluated ranged from 4.8 to 6.3 mg/L, with the percentage of particles less than 55 μm ranging from 69.75% to as high as 86.1%. The drum filter removed over 90% of the particles larger than 55 μm and removed 8–26% of the particles smaller than 55 μm. No difference was observed in the overall removal efficiency of the drum filter, which ranged from 19% to 44%. There was no significant difference in the foam fractionator overall removal efficiency, which ranged from 6.5% to 38.5%. Operating the foam fractionator at a high water head height (HHH) with the submersible aspirating impeller provided the greatest removal percentage of particles less than 55 μm (26.9%). However, at the HHH, only half the amount of solids was removed compared to using a Venturi injector with ozone, but energy use was roughly 26% greater.ConclusionThe foam fractionator was operated at the HHH, about 0.31 m higher than the low water head height, for production operation. Additionally, Venturi injection of ozone provided the greatest removal of solids for the volume of influent water treated over a 12‐h operational period. The submersible aspirating impeller showed potential for low‐cost use with reasonable solids removal and warrants further evaluation.

Effects of Red and Blue Light on the Growth, Photosynthesis, and Subsequent Growth under Fluctuating Light of Cucumber Seedlings.

The effects of red and blue light on growth and steady-state photosynthesis have been widely studied, but there are few studies focusing on dynamic photosynthesis and the effects of LED pre-treatment on cucumber seedlings' growth, so in this study, cucumber (Cucumis sativus L. cv. Jinyou 365) was chosen as the test material. White light (W), monochromatic red light (R), monochromatic blue light (B), and mixed red and blue lights with different red-to-blue ratios (9:1, 7:3, 5:5, 3:7, and 1:9) were set to explore the effects of red and blue light on cucumber seedlings' growth, steady-state photosynthesis, dynamic photosynthesis, and subsequent growth under fluctuating light. The results showed that compared with R and B, mixed red and blue light was more suitable for cucumber seedlings' growth, and the increased blue light ratios would decrease the biomass of cucumber seedlings under mixed red and blue light; cucumber seedlings under 90% red and 10% blue mixed light (9R1B) grew better than other treatments. For steady-state photosynthesis, blue light decreased the actual net photosynthetic rate but increased the maximum photosynthetic capacity by promoting stomatal development and opening; 9R1B exhibited higher actual net photosynthetic rate, but the maximum photosynthetic capacity was low. For dynamic photosynthesis, the induction rate of photosynthetic rate and stomatal conductance were also accelerated by blue light. For subsequent growth under fluctuating light, higher maximum photosynthetic capacity and photoinduction rate could not promote the growth of cucumber seedlings under subsequent fluctuating light, while seedlings pre-treated with 9R1B and B grew better under subsequent fluctuating light due to the high plant height and leaf area. Overall, cucumber seedlings treated with 9R1B exhibited the highest biomass and it grew better under subsequent fluctuating light due to the higher actual net photosynthetic rate, plant height, and leaf area.

Additive manufacturing of Fe28.2Mn32.9Ni18.8Cr6Al14.1 high-entropy alloy by applying consumable fillers of metal powders and polyvinyl alcohol

Simultaneous application of welding methods and metal additive manufacturing facilitates the production of various 3D physical samples from metals and alloys. One of the technical impediments, especially for additive manufacturing of high entropy alloys, is the variety of elements in their chemical composition that makes the fabrication of fillers in welding methods very challenging. In the present research, the additive manufacturing of Fe28.2Mn32.9Ni18.8Cr6Al14.1 high entropy alloy with the use of consumable fillers, including metal powders and polyvinyl alcohol binder through gas tungsten arc welding process has been investigated. To perform the gas tungsten arc welding process, the experiments were designed using the Taguchi method. The parameters of current, torch angle, torch speed, and substrate temperature were selected as the input parameters. Then, through Grey analysis, the optimum width and height of the weld bead were determined to deposit thin layers with high height and low width. The results of the experiments confirmed that the proposed method for fabricating consumable fillers successfully performed layer-by-layer deposition of the sample using the gas tungsten arc welding process. Moreover, the elemental mapping images proved the presence of all elements in the Fe28.2Mn32.9Ni18.8Cr6Al14.1 sample. Furthermore, no internal voids were detected upon inspection of the fabricated sample using a micro-computed tomography scanner.

Habitat requirements of deadwood-dependent invertebrates that occupy tree hollows.

Tree hollows support a specialised species-rich fauna. We review the habitat requirements of saproxylic (= deadwood dependent) invertebrates which occupy tree hollows. We focus on studies quantifying relationships between species occurrence patterns and characteristics of tree hollows, hollow trees, and the surrounding landscape. We also explore the processes influencing species occurrence patterns by reviewing studies on the spatio-temporal dynamics of populations, including their dispersal and genetic structure. Our literature search in the database Scopus identified 52 relevant publications, all of which were studies from Europe. The dominant taxonomic group studied was beetles. Invertebrates in hollow trees were often more likely to be recorded in trees with characteristics reflecting a large amount of resources or a stable and warm microclimate, such as a large diameter, large amounts of wood mould (= loose material accumulated in the hollows mainly consisting of decaying wood), a high level of sun exposure, and with entrance holes that are large and either at a low or high height, and in dry hollows, with entrances not directed upwards. A stable microclimate is probably a key factor why some species of saproxylic invertebrates are confined to tree hollows. Other factors that are different in comparison to downed dead wood is the fact that hollows at a given height from the ground provide shelter from ground-living predators, that hollows persist for longer, and that the content of nutrients might be enhanced by the accumulation of dead leaves, insect frass, and remains from dead insects. Several studies have identified a positive relationship between species occupancy per tree and the amount of habitat in the surrounding landscape, with a variation in the spatial scale at which characteristics of the surrounding landscape had the strongest effect over spatial scales from 200 to 3000 m. We found empirical support for the extinction threshold hypothesis, which predicts that the frequency of species presence per tree is greater if a certain number of trees are aggregated into a few large clusters of hollow trees rather than distributed among many small clusters. Observed thresholds in species occurrence patterns can be explained by colonisation-extinction dynamics, with species occupancy per tree influenced by variation in rates of immigration. Consistent with this assumption, field studies suggest that dispersal rate and range can be low for invertebrates occupying tree hollows, although higher in a warmer climate. For one species in which population dynamics has been studied over 25 years (Osmoderma eremita), the observed population dynamics have characteristics of a "habitat-tracking metapopulation", as local extinctions from trees occur possibly because those trees become unsuitable as well as due to stochastic processes in small populations. The persistence of invertebrate fauna confined to tree hollows may be improved by prolonging the standing life of existing hollow trees. It is also important to recruit new generations of hollow trees, preferably close to existing larger groups of hollow trees. Thus, the spatio-temporal dynamics of hollow trees is crucial for the invertebrate fauna that rely upon them.

Mussel-inspired poly-norepinephrine coatings as “slippy-sticky interlayer” for fabricating high-energy insensitive energetic composites

Inspired by the super-adhesive properties in marine mussel, a desensitized energetic powder constituted of a slippy-sticky polynorepinephrine interlayer and CL-20 microcore is reported. The slow polymerization process enables the extremely smooth and multifunctional thin-coating formed onto the CL-20 surface. Based on the designed composites, the calculated electronic energy values of all 15 optimized structures reveals a spontaneous thermodynamic process and a stronger bonding strength with the increase of polymerization degree. The H50values of NE/CL-20 structure are calculated and show a significant increase for new composite, produced by the bonding of norepinephrine with CL-20, versus pure CL-20. The subsequent experimental results demonstrate that the slippy CL-20@polynorepinephrine structure exhibits a high drop height (H50, 35.5 cm) and a low explosion probability (60 %) than that of pure CL-20, even exhibits a considerable increase and decreases by 13.3 cm and 12 % in turn versus CL-20@polydopamine under the identical experimental conditions. The sensitive simulation results indicate that the shorter NN bond length and lower area percent in electrostatic potential of samples are positively correlated with the decreasing of impact sensitivity. Note that the ultrasmooth bionic interlayer gives the super-adhesive properties of energetic powder, greatly improves the coating degree of 2D material, thereby shows a lower sensitivity and a high detonation heat for the constructed double-coating composites (CL-20@PNE@GO). To sum up, this study will provide an innovative route to construct a high-safety powder based on a bionic sticky interlayer strategy.

Zinc-exchanged montmorillonite clay: A promising slow-release nanofertilizer for rice (Oryza sativa L.)

This study is to examine zinc exchanged montmorillonite (Zn-MMT) as a potential slow release nanofertilizer for rice crop. The effective intercalation of zinc within the montmorillonite inter layers was firmly established via analytical techniques including Zeta potential, FE-SEM (Field Emission Scanning Electron Microscopy) with Energy Dispersive X-ray Analysis (EDAX), Transmission Electron Microscope (TEM), X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR). The efficacy of Zn-MMT was examined by evaluating its ability to facilitate controlled zinc release, as confirmed through an incubation study. Subsequently, the kinetics of zinc release was analyzed by different mathematical models such as Zero-order kinetics, First-order kinetics, the Higuchi model, and the Korsmeyer-Peppas model. From the pot culture study spanning 90 days the results indicated that Zn-MMT had significantly high plant height, Leaf Area Index (LAI), Dry Matter Production (DMP), number of tillers per hill, panicles length, increased grain and straw yield, in comparison with conventional zinc sulphate (ZnSO4). Total phenol, total protein and total chlorophyll content were significantly at higher levels with Zn-MMT treated rice crops as compared to conventional fertilizers and control. A similar trend was seen with phytochemicals such as Indole Acetic Acid (IAA), Superoxide Dismutase (SOD) and Carbonic Anhydrase (CA). Notably, rice grains harvested from Zn-MMTtreated crops exhibited significantly higher zinc content than those using other treatments. This Zn-MMT can be confirmed as a better alternative to conventional zinc sulphate fertilizers owing to its slow-release of nutrient into the soil and thus increased zinc use efficiency.

Accuracy and Resolution of SWOT Altimetry: Foundation Seamounts

AbstractWe assess the accuracy and spatial resolution of the surface water and ocean topography (SWOT) swath altimeter for deriving marine gravity anomalies. The analysis is performed at the Foundation Seamounts in the South Pacific where we developed a highly accurate gravity field by combining the long‐wavelength (>40 km) gravity field derived from previous nadir altimeters with the shorter wavelength gravity field from the seafloor topography as constrained by the ship gravity. In this region, the sea surface slope (SSS) of the ocean variability is 50–100 times smaller than the slope signal of the seamounts so can be ignored in the analysis. Each SWOT cycle can deliver SSS accurately with a standard deviation of 2.6 µrad and a spatial resolution of 14 km at typical sea state (significant wave height 4 m), with accuracy diminishing at high significant wave heights (e.g., exceeds 6 m). Averaging repeated SWOT measurements improves the accuracy and resolution. For example, we expect that averaging just 10 repeats (7 months) results in accuracy/resolution that matches the best marine gravity maps based on 230 months of nadir altimetry. With a mission lasting over a year, SWOT promises a substantial leap in marine gravity accuracy and resolution, uncovering previously uncharted details of the seafloor, including thousands of uncharted seamounts.

CFD simulation study and experimental analysis of indoor air stratification in an unventilated classroom: A case study in Spain

Health problems and respiratory diseases are associated with poor indoor air ventilation. We investigated the air quality inside a classroom-laboratory where no ventilation is provided. The case of study, consisting of an internal enclosure, is located at the Escuela Técnica Superior de Edificación (ETSEM) of Madrid (Spain). The high height favours air stratification which is analysed in terms of temperature and CO2 spatial distribution. Temperature, air humidity, atmospheric pressure and CO2 concentration measurements were taken in time at three different height locations. A CFD numerical model was established to analyse air quality. Flow circulation is derived by solving full 3D Navier – Stokes governing equations, coupled with the thermal problem. The diffusion problem of the CO2 produced by the inner occupants is then derived from the kinematics solution. Three scenarios were taken into account: occupants seated (1), standing (2), half seated, half standing (3). Results clearly show the air stratification as a result of density gradient, which is in turn determined by temperature difference between the occupants and the surrounding air. Temperature prediction maximum relative error is contained to 3.5 %. As expected, CO2 concentration increases over time, reaching maximum values depending on the configuration considered and height location.

Studies of carrier transport mechanism in NiO/Ag/NiO transparent conducting electrode/ZnO metal-semiconductor-metal photodetectors

Oxide/metal/oxide multilayers as a transparent conducting electrode (TCE) have been developed to replace metals due to their high transparency and low sheet resistance. Nickel oxide (NiO) film with a high work function was used as an oxide to form NiO/Ag/NiO (NAN) TCE, therefore a high barrier height between NAN/zinc oxide (ZnO) interface. In the study, NAN TCE was deposited on ZnO surface to fabricate metal-semiconductor-metal (MSM) photodetectors (PDs) and study its carrier transport mechanism. The NAN TCE has a low sheet resistance of 6.5 Ω/sq. and transmittance more than 40% in a 300−1000 nm wavelength range. Such issues result in the figure-of-merit is higher (2.3 × 10−4 Ω−1) than that (2.5 × 10−7 Ω−1) of pure single NiO thin film. As compared to the conventional Au/ZnO MSM-PDs, the NAN/ZnO MSM-PDs demonstrates a lower leakage current as a result of Ni atoms diffusing into ZnO and passivating the defects. Due to the high work function of NiO, the NAN/ZnO interface exhibits a barrier height as high as 0.91 eV. The Au/ZnO MSM-PDs reveals only one carrier conduction of ohmic due to the electrons tunnel form Au into ZnO through the surface defects. In contrast, two distinct carrier transport mechanisms were observed in the NAN/ZnO MSM-PDs. At low-voltage for V⩽0.64 V , ohmic conduction dominates and the electrons inject from NAN to ZnO, trapped by the defect states of ZnO. At high-voltage for V⩾0.64 V , the trapped electrons acquire enough energy and emit from trap to conduction band, entering Poole–Frankel emission transport.

Research on the Movement of Overlying Strata in Shallow Coal Seams with High Mining Heights and Ultralong Working Faces

To study the roof movement and ground pressure evolution characteristics of an ultralong working face in a shallow coal seam with a high mining height, the Shangwan Coal Mine in the Shendong mining area was used as the research background, and the physical and mechanical parameters of the surrounding rock were determined through rock mechanics experiments. A physical simulation model was built considering the 7 m mining height of the 12301 fully mechanized working face of the Shangwan Coal Mine to simulate and study the evolutions of the movement, fracture and collapse of the coal seam, direct roof, and basic roof and overlying strata during the mining process. The mechanical characteristics of the support, mechanism of roof collapse, and changes in the working resistance of the support were analysed and simulated. The research results indicate that when mining at a height of 7 m, the direct roof and basic roof strata collapse in layers; the basic roof strata collapse backwards, the rock block arrangement is more irregular, and the range of the basic roof that can form structural rock layers extends higher. After the basic roof rock fractures, it cannot form a masonry beam structure and can only form a cantilever beam structure. The periodic fracture of the cantilever beam causes periodic pressure on the working face. These research results are of great significance for planning the further mining of shallow coal seams with high mining heights and ultralong working faces in the Shendong mining area, as well as for improving the control of overlying strata.

MeGT2.6 increases cellulose synthesis and active gibberellin content to promote cell enlargement in cassava.

Cassava, a pivotal tropical crop, exhibits rapid growth and possesses a substantial biomass. Its stem is rich in cellulose and serves as a crucial carbohydrate storage organ. The height and strength of stems restrict the mechanised operation and propagation of cassava. In this study, the triple helix transcription factor MeGT2.6 was identified through yeast one-hybrid assay using MeCesA1pro as bait, which is critical for cellulose synthesis. Over-expression and loss-of-function lines were generated, and results revealed that MeGT2.6 could promote a significant increase in the plant height, stem diameter, cell size and thickness of SCW of cassava plant. Specifically, MeGT2.6 upregulated the transcription activity of MeGA20ox1 and downregulated the expression level of MeGA2ox1, thereby enhancing the content of active GA3, resulting in a large cell size, high plant height and long stem diameter in cassava. Moreover, MeGT2.6 upregulated the transcription activity of MeCesA1, which promoted the synthesis of cellulose and hemicellulose and produced a thick secondary cell wall. Finally, MeGT2.6 could help supply additional substrates for the synthesis of cellulose and hemicellulose by upregulating the invertase genes (MeNINV1/6). Thus, MeGT2.6 was found to be a multiple regulator; it was involved in GA metabolism and sucrose decomposition and the synthesis of cellulose and hemicellulose.

APPLICATION OF NONPARAMETRIC REGRESSION SPLINE TRUNCATED FOR MODELING THE HEIGHT OF YEOP CHAGI KICKS OF TAEKWONDO ATHLETES IN SAMARINDA CITY

Nonparametric regression is a model approach method that is used when the shape of the regression curve between the response variable and the predictor variable is assumed to have an unknown shape or pattern. One of the estimators in the nonparametric regression approach is the truncated spline which has the ability to handle data whose behavior changes at certain sub intervals. The purpose of this study was to obtain the estimated value of the parameters of the nonparametric regression model with a truncated spline approach at one knot point, two knot points, and three knot points for kick height data of yeop chagi taekwondo athletes in Samarinda City. The results showed that the truncated spline nonparametric regression model was the best in modeling high kick height data for yeop chagi taekwondo athletes in Samarinda City with three knot points. This model has the minimum Generalized Cross Validation (GCV) value of 7.94 with an R2 value of 94.72% and a Mean Square Error (MSE) value of 2.62. Based on the results of the model parameter significance test, it was concluded that the factors that influence the kick height of the yeop chagi taekwondo athlete in Samarinda City are flexibility, leg power, leg length, and waist circumference.

Turbulent vortex pair at equilibrium and its interaction with the ground at

A turbulent two-vortex system (T-2VS) is obtained by inserting analytical model wake vortices into very weak homogeneous isotropic turbulence (HIT) and by evolving them in time using large-eddy simulation until a turbulent state at statistical equilibrium is reached. The T-2VS is characterised as follows: circulation distribution of the vortices; energy of the mean and fluctuating fields; energy dissipation rate. It is also verified that essentially the same T-2VS is obtained when varying the initial model or initial HIT perturbation. A wall-resolved simulation of the T-2VS further interacting with a smooth ground is then performed at $Re_\varGamma = 2 \times 10^5$ ; this is $10 \times$ higher than in previous works, which allows us to better capture the high Reynolds number behaviour. The high release height of the T-2VS also ensures a physically correct approach to the ground. The results are compared with the literature and also to what is obtained for the case of non-turbulent vortices interacting with the same ground at the same Reynolds number. The flow topologies are discussed, and significant differences are highlighted regarding the separation of the boundary layer generated at the ground, and the way this secondary vorticity interacts with the primary vortices and makes them decay. The vortex trajectories are also measured, together with their circulation distribution and global circulation evolution, and the differences are discussed.

Research on the Dust Transport Law in Large Mining Height Fully Mechanized Mining Face

The fully mechanized mining face with high mining height has always been a high-risk area for coal mine dust pollution. In order to further understand the spatiotemporal transport law of dust in the zoning of the high mining height fully mechanized mining face, the 122109 high mining height fully mechanized mining face of Caojiatan Coal Mine was taken as the research object. Numerical simulation method was used to simulate and analyze the dust transport situation of the 122109 fully mechanized mining machine drum single dust source, the hydraulic support moving frame single dust source, and the superposition of all dust sources in forward and backward wind cutting coal. The research results can guide the ventilation layout design in the early stage of the mine and the dust control in the comprehensive mining process, which is of great significance for the construction of safe and green mines.