Gap Area Research Articles

Understanding the formation of “false friends” (hidden lack of fusion defects) in laser beam welding by means of high-speed synchrotron X-ray imaging

This paper provides a fundamental understanding of “false friend” formation, i.e., hidden defects associated with lack of fusion, using an experimental setup that allowed an insight into the processing zone based on high-speed synchrotron X-ray imaging. The setup enabled the welding of a lap joint of AISI 304 high-alloy steel sheets (X5CrNi18-10/1.4301), with the ability to adjust different gap heights between top and bottom sheet (up to 0.20 mm) and to acquire high-speed X-ray images at 100 kHz simultaneously with the welding process. On this basis, a time-resolved description of the “false friend” formation can be provided by visualizing the interaction between keyhole and melt pool during laser welding and solidification processes within the gap area. The bridgeability of the gap was limited due to the gap height and insufficient melt supply leading to the solidification of the bridge. The distance between the solidified bridge and the keyhole increased with time, while the keyhole and melt pool dynamics initiated the formation of new melt bridges whose stability was defined by melt flow conditions, surface tension, and gap heights. The alternating formation and solidification of melt bridges resulted in entrapped areas of lacking fusion within the weld, i.e., “false friends.” Finally, based on the results of this study, a model concept is presented that concludes the main mechanisms of “false friend” formation.

Canopy gaps and associated losses of biomass – combining UAV imagery and field data in a central Amazon forest

Abstract. Understanding mechanisms of tree mortality and the dynamics of associated canopy gaps is relevant for robust estimates of carbon balance in forests. We combined monthly RGB images acquired from an unoccupied aerial vehicle with field surveys to identify gaps in an 18 ha plot installed in an old-growth central Amazon forest. We measured the size and shape of gaps and analyzed their temporal variation and correlation with rainfall over a period of 28 months. We further described associated modes of tree mortality (i.e., snapping, uprooting and standing dead) and branch fall and quantified associated losses of biomass. In total, we detected 32 gaps either in the images or field ranging in area from 9 to 835 m2. Relatively small gaps (< 39 m2) opened by branch fall were the most frequent (11 gaps). Out of 18 gaps for which both field and image data were available, three could not be detected remotely. Gaps observed in the field but not captured on the imagery were relatively small and mainly formed by the fall of branches from live and standing dead trees. Our data show that ∼ 17 % of the tree-mortality and branch-fall events only affected the lower canopy and the understory of the forest and are likely neglected by top-of-the-canopy assessments. Regardless of the detection method, the size distribution was best described by a lognormal function for gaps starting from the smallest detected size (9 and 10 m2 for field and imagery data, respectively), and the Weibull and Power functions for gaps larger than 25 m2. Properly assessing associated confidence intervals requires larger sample sizes. Repeated field measurements reveal that gap area does not differ significantly among modes of tree mortality or branch fall in central Amazon forests, with the last contributing the least to biomass loss. Predicting mechanisms of gap formation based on associated area and biomass loss remains challenging, which highlights the need for larger datasets. The rate of gap area formation was positively correlated with the frequency of extreme rainfall events, which may be related to a higher frequency of storms propagating extreme rain and wind gusts. While remote sensing has proven to be an accurate and precise method for mapping gaps compared to field data (i.e., ground truth), it is important to note that our sample size was relatively small. Therefore, the extrapolation of these results beyond our study region and landscape shall be made cautiously. Apart from improving landscape assessments of carbon balance, regional information on gap dynamics and associated mechanisms of formation are fundamental to address forest responses to altered disturbance regimes resulting from climate change.

Appraisal of Water Resources Development Action Plan for Groundwater Recharge in Raghunathapalli Watershed, Jangaon District, Telangana State, India

Water is elixir of life which needs regular assessment for maintaining ecological balance. Micro watershed wise (a few thousand hectares of extent) water resource action plan is need of the hour especially for a hard rock terrain like Raghunathapalli watershed of Jangaon District. Geologically, the area is underlain by Quartzite and Pelitic Schist of Older Metamorphics and Leuco Granite / Grey Alkali FelpsarGranite Terrain (Peninsular Gneissic Complex) belonging to Archeans. The Archeans are intruded at several places by several Pegmatite Veins and Basic Dolerite Dykes. The average annual rainfall of the study area for the past 19 years is 946 mm and that of monsoonal rainfall is 746 mm. In order to do artificial ground water recharge, the study and analysis of parameters that control the ground water recharge is very important for effective ground water recharge. The spatio-temporal variations in rainfall, regional/local distribution in geological formations and geomorphic composition of various units have led to uneven occurrence and distribution of water resources. Different thematic layers like Geology, Geomorphology, Stream Network, Micro Watersheds, Digital Elevation Model, Contours (2m), Base Layers, Soil and Ground Water Potential maps are prepared using Geospatial technologies like Remote Sensing & GIS. Existing Recharge Structures are marked using 1:25,000 scale Survey of India Toposheets and new locations are updated with high resolution satellite imagery. Micro watershed wise Water Balance studies are carried out and Water Resources Development Action Plan is prepared using Ridge to Valley concept with new artificial recharge structures like Check Dams (22), Percolation Tanks (10), Contour Trenches (68Kms), Subsurface Dyke (2), Farm Pond (268), Recharge Pit (179), Recharge Shaft (16), Desilting Tank (24 nos) etc at suitable terrain conditions. Newly proposed locations for constructions of Rainwater harvesting structures in the gap areas will improve the ground water regime and improves the sustainability of wells for agriculture in the drought prone area of Raghunathapalli watershed. Thus Geospatial technologies are cost effective tools for management and conservation of water resources.

Quantitative Evaluation of Vocal Bowing Following Bilateral Thyroplasty in Age-Related Vocal Atrophy.

Age-related vocal atrophy (ARVA) is associated with vocal fold bowing, persistent glottal gap during phonation, and dysphonia. Bilateral medialization thyroplasty is sometimes performed in patients with ARVA to improve vocal fold closure and voice. We set out to quantify stroboscopic changes in vocal fold bowing, glottal closure, and abduction angle following bilateral thyroplasty and determine how these changes affect voice quality among patients with ARVA. Fifteen individuals with ARVA who underwent bilateral medialization thyroplasty were included in this study. Two independent investigators calculated bowing index (BI), normalized glottal gap area (NGGA), and maximum abduction angle from laryngostroboscopic exams using ImageJ™. Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) and patient-reported measures were collected before and after thyroplasty. Thyroplasty resulted in a 10-point improvement in overall CAPE-V (Mean dif -10; 95% CI -17, -3.3, p < 0.01) and VHI-10 (mean dif -3.8; 95% CI -9.8, 2.3, p = 0.19, n = 8). NGGA and BI significantly decreased following surgery (mean dif -78; 95% CI -155, -1.5, p = 0.05; and mean dif -2.1; 95% CI -2.4, -0.84, p < 0.01, respectively). BI correlated with CAPE-V scores (r = 0.66, 95% CI 0.22, 0.87, p < 0.01). When considering the normalized combined contributions of both NGGA and BI, there was a stronger correlation in CAPE-V scores (r = 0.87, 95% CI 0.50, 0.97, p < 0.01) compared with either measure alone. Thyroplasty resulted in a decrease in vocal fold bowing, glottal gap area, and CAPE-V scores in patients with ARVA. Correction of vocal bowing and glottal gap, following bilateral thyroplasty, improved voice measures following surgery. Quantitative evaluation of vocal fold morphology may be valuable when assessing the severity and treatment-response in patients with ARVA following bilateral thyroplasty. Laryngoscope, 134:835-841, 2024.

Adjusting the protected areas on the Tibetan Plateau under changing climate

The intensifying climate change crisis threatens the distribution within ecosystems and their function. Protected areas should incorporate the changing climate into planning to improve the effectiveness of biological conservation, particularly for biodiversity hotspots facing fast climate change. In this study, we investigated the climate-smart planning for protected areas in the Tibetan Plateau, known as the Third Pole, under climate change scenarios. These areas comprise unique ecosystems and three biodiversity hotspots of the world. The Species distribution model and carbon model with a systematic conservation planning tool (Marxan) were coupled in a unified framework. The economic costs (population) and climate costs (climate velocity, namely, a metric reflecting the impacts of climate change on species shifts) were input into the Marxan model to conduct hierarchical planning and further identify the areas functioning as species conservation priority areas or climate refugia under different climate scenarios. Results showed that nearly 10 % of the existing protected areas would suffer from rapid climate change in the future, leading to climate space loss in current protected areas by more than 20 %. The hierarchical planning realized relatively low economic and climate costs but left 58 % gap areas outside current conservation network. Therefore, six adjustable areas in the eastern and southern Tibetan Plateau, particularly in the margins of the plateau, were identified as: the gap areas (1) adjacent to the southwest of Qilian Mountains, (2) on the southeast of the headwaters of the Yellow River, (3) on the southeast of the headwaters of the Lancang River, (4) in Zayu and Mêdog, (5) connecting Mount Qomolangma Nature Reserve and Middle Reaches of the Yarlung Zangbo Valley—the Black-necked Cranes Nature Reserve, and (6) in the northwest of Zanda. These areas were proved to perform complex ecological functions under future climate scenarios. Our findings emphasize the necessity to account for climate impacts on protected area planning. The framework can help enhance the ability of the Tibetan Plateau as ecological security barrier and guide the climate-smart design of protected areas in China.

Characterization method for electric arc erosion based on the in-situ measurement of electrode surface morphology

The electrical arc significantly influences the surface morphology and the performance of electrode. There has been ever increasing demand for the characterization method of arc erosion. In this work, an in-situ test rig has been described that makes it possible to measure the surface height point cloud data and the microscopic images consecutively during arc erosion cycling. Novel processing algorithms considering the eroded electrode morphology are proposed for characteristic parameters calculation including arc erosion volume, electrode gap and contact area. It has been observed that the inner layer metals of electrode are heated and ejected to the surface after arcing, which form higher bulges with pores. And the electrode gap decreases under higher arc erosion volume. Moreover, in the electrical endurance experiment, the change trends of contact area correlate well with the measured resistance. Based on the collected sensitive parameters, the cumulative arc erosion on the electrode surface is characterized.

Safety and Efficacy of Bone Marrow-Derived Mesenchymal Stem Cells for Chronic Patellar Tendinopathy (With Gap >3 mm) in Patients: 12-Month Follow-up Results of a Phase 1/2 Clinical Trial.

In a previous study, the authors found that at 6 months after treatment with a 20 × 106 dose of bone marrow-derived mesenchymal stem cells (BM-MSCs), patients showed improved tendon structure and regeneration of the gap area when compared with treatment using leukocyte-poor platelet-rich plasma (Lp-PRP). The Lp-PRP group (n = 10), which had not seen tendon regeneration at the 6-month follow-up, was subsequently offered treatment with BM-MSCs to see if structural changes would occur. In addition, the 12-month follow-up outcomes of the original BM-MSC group (n = 10) were evaluated. To evaluate the outcomes of all patients (n = 20) at 12 months after BM-MSC treatment and observe if the Lp-PRP pretreated group experienced any type of advantage. Cohort study; Level of evidence, 2. Both the BM-MSC and original Lp-PRP groups were assessed at 12 months after BM-MSC treatment with clinical examination, the visual analog scale (VAS) for pain during daily activities and sports activities, the Victorian Institute of Sport Assessment-Patella score for patellar tendinopathy, dynamometry, and magnetic resonance imaging (MRI). Differences between the 2 groups were compared with the Student t test. The 10 patients originally treated with BM-MSCs continued to show improvement in tendon structure in their MRI scans (P < .0001), as well as in the clinical assessment of their pain by means of scales (P < .05). Ten patients who were originally treated with Lp-PRP and then with BM-MSCs exhibited an improvement in tendon structure in their MRI scans, as well as a clinical pain improvement, but this was not significant on the VAS for sports (P = .139). Thus, applying Lp-PRP before BM-MScs did not yield any type of advantage. The 12-month follow-up outcomes after both groups of patients (n = 20) received BM-MSC treatment indicated that biological treatment was safe, there were no adverse effects, and the participants showed a highly statistically significant clinical improvement (P < .0002), as well as an improvement in tendon structure on MRI (P < .0001). Preinjection of Lp-PRP yielded no advantages.

The response of seedlings and saplings to canopy structure and light in different gaps in a spruce-fir mixed stand in Changbai Mountains, China

Environmental heterogeneity caused by the formation of forest gaps has important implications for the establishment and growth of forest regeneration, and different tree species with different shade tolerance at various stages of regeneration respond differently to the environment. In this study, we investigated 48 forest gaps and classified them into four classes based on their area, including small (< 20 m2), medium (20 m2 to 50 m2), large (50 m2 to 120 m2), and extra-large (> 120 m2). We conducted an analysis of the differences and variations in canopy structure (canopy openness and leaf area index (LAI)) and light environment (direct light, diffuse light, and total light) for different sizes of gaps and along the north–south axis of the gaps. Additionally, we conducted a preliminary study of how the seedlings and saplings of different tree species (Korean pine (Pinus koraiensis), Ezo spruce (Picea jezoensis), and Khingan fir (Abies nephrolepsis)) respond to environmental factors such as canopy structure and light within gaps. Gap size significantly influenced the direct and total light in northern (N, N1) portion of gaps, while for diffuse light, gap size demonstrated a notable effect along the north–south axis, except for the N. Maximum direct light did not occur at the center of gaps, but rather near the center of the gap and tended to the crown edge. In contrast, the maximum diffuse light occurred at the center of gap. When the forest gap area < 20 m2, the diffuse light dominated the northern part of the gaps. However, when the gap area > 20 m2, the northern part was dominated by direct light. The variation pattern of total light showed a level of consistency with that of direct light. A redundancy analysis (RDA) showed that the density of shade-tolerant fir seedlings and saplings, as well as spruce seedlings, were primarily positively correlated with the LAI, while the density of spruce saplings was negatively correlated with direct light. The density of heliophilous species Korean pine seedlings and saplings was strongly and weakly positively correlated with the direct light, respectively. The mean ground diameter and height of spruce and fir seedlings and saplings positively correlated with diffuse light, whereas the mean ground diameter and mean height of Korean pine seedlings and saplings strongly positively correlated with the canopy openness and direct light, respectively. These findings suggest that the gap size and location within gaps can compensate each other in silvicultural practices based on the creation of gaps. Knowledge of the ecological characteristics of the target species, enables the selection of appropriate relative positions to achieve more suitable light conditions for their growth.

The state of embedded librarianship in the university research processes in selected African academic libraries

PurposeThis study aims to examine the state of embedded librarianship in African academic libraries by exploring the extent of librarian embedment in research processes in selected academic libraries in Africa.Design/methodology/approachA survey was conducted to collect data using an online questionnaire. The study population was comprised of librarians who directly support researchers throughout the research process in the scholarly communication and information services sections. Purposive sampling was used to select librarians, and 63 responses were received from the target of 100. The collected data were analysed using the statistical package for the social sciences (SPSS) software, and content analysis was used to analyse open-ended questions.FindingsThe study results showed that the extent and nature of librarians' embeddedness in the research process vary across different university contexts in Africa. Challenges and areas of research skill gaps among librarians were identified, and propositions to address the research skill gaps were provided.Practical implicationsThe study findings can be used as a framework for libraries to embed librarians in the research process. The study made recommendations with practical implications for library practitioners in academia, and institutions offering library and information science education, and the library management responsible for the research process.Originality/valueA study brings a novel perspective by examining the state of embedded librarianship in the African context. Its contribution generates knowledge and insights that inform the development of effective embedded librarianship practices in African academic libraries to enhance research support services and advancement of scholarly research in the region.

Thermal behavior and morphology evolution of polyamide 12 in laser powder bed fusion process: Experimental characterization and numerical simulation

A particle scale numerical model of laser powder bed fusion (L-PBF) for semi-crystalline polymer PA12 is presented in this work. The model is developed by the finite element method under the framework of the level-set method. The asymmetrical and kinetical thermal behavior of semi-crystalline polymer is implemented in the thermal model, enabling better considering the latent heats during different phase transformation processes. Particle consolidation under laser irradiation is simulated by hydrodynamics. The physical properties of PA12 powder are identified by experiments regarding the inputs of the numerical model. Before performing L-PBF processing simulations, the numerical powder bed model, the implementation of crystallization kinetics, and the related hydrodynamic parameters are verified by comparing simple simulations with the experiments. The influence of phase transformation latent heat on the temperature calculation and the consequent melt pool profile is discussed in the single-track simulation: the peak temperature on the top surface of the substrate is significantly lower when properly considering the re-melting fusion latent heat with the modified crystallization kinetics. As a result, a shallower melt pool is obtained. The effect of processing parameters on the temperature field and shape of the melt pool is also modeled. This parametric study indicates that decreasing the scanning velocity can eliminate the inter-layer lack of fusion phenomenon. Additionally, the thermal interaction between adjacent scanning tracks can improve the fusion continuity in the gap area of neighbor tracks. Finally, optical observations are conducted to validate the simulated morphology of the melt pool. A good agreement between numerical results and experimental observations is obtained, indicating the ability of the numerical model to simulate the PA12 L-PBF process.

ОПРЕДЕЛЕНИЕ КОЭФФИЦИЕНТА ЗАГРУЗКИ МАТЕРИАЛА В КАМЕРЕ ПОМОЛА ШАРОВОЙ БАРАБАННОЙ МЕЛЬНИЦЫ

The predominant application of ball drum mills in industrial enterprises for the comminution process of various materials, which is one of the most energy-intensive basic technological processes, is demonstrated in this scientific article. As one of the parameters that can enhance the efficiency of the comminution process, the rational quantitative ratio of grinding bodies to the material being ground is noted. To calculate the material loading coefficient in the grinding chamber, the feasibility of developing a mathematical description is shown. This allows to determine the change in the area of gaps between grinding bodies in a cross-sectional plane perpendicular to the longitudinal axis of the mill's body, as the rotational frequency changes. A mathematical description is obtained to determine the area of the ball-material load in the cross-sectional plane of the grinding chamber during the static state of the mill's body and at different rotational frequencies. Using this mathematical description, research on the change in the area occupied by the ball-material load in the transverse section of the grinding chamber during the transition of the mill's body from the static state to the operating state is conducted. Regularities of its changes for an industrial-sized mill are determined. At different values of the filling coefficient of grinding bodies, it is established that the transition of the mill's body from static to operating state leads to an increase in the area of the transverse section of the ball-material load by an amount close to 17 %. An expression is proposed to determine the material loading coefficient in the grinding chamber corresponding to its operating rotational frequency.

Socioeconomic driving forces of land use/cover changes in the semi-arid Harran plain and their probable implications on arising groundwater level, the GAP area of southeastern Türkiye

Socioeconomic driving forces of land use/cover changes in the semi-arid Harran plain and their probable implications on arising groundwater level, the GAP area of southeastern Türkiye

Experimental and calculation investigations of hydrodynamics and heat exchange in liquid metal turbulent flows in fast reactor fuel assemblies

The formation of velocity and temperature fields in the fuel assemblies of fast reactor core occurs under the influence various factors. It is shown, that the most important factors include a complex multiply connected geometry, subject to deformation during the campaign under the influence of temperature non-uniformity and radiation effects. The results of studies of the velocity fields and shear stress, turbulence microstructure are presented. An intensification of turbulent momentum transfer in channels in azimuthal and radial directions in the area of gaps between the rods is demonstrated. The performed analysis is indicate that there are a significant difference between the experimental dependences for turbulent momentum transfer coefficients in the radial and azimuthal directions and calculated within the framework of semi-empirical models of turbulent momentum transfer as well as the anisotropy coefficients of the turbulent momentum transfer in rod bundles. The results of benchmark on the fuel assembly thermohydraulics showed that the common commercial codes describe experimental data only approximately. It is shown, that the intensification of turbulent momentum transfer in the channels of rod bundles is due to the appearance of large-scale turbulent momentum transfer (secondary flows). The contribution of large-scale turbulent momentum transfer to the turbulent momentum transfer coefficients in the channels of rod bundles is calculated. The dependence for coefficient of inter-channel turbulent exchange of momentum is obtained and the intensification of inter-channel turbulent exchange in close-packed rod lattices is explained. A dependence for the dissimilarity coefficients of forced inter-channel convective exchange of momentum and mass, as well as energy and mass in rod bundles spaced by wire winding is obtained. The calculation methods and the numerical modeling results for temperature regime of fuel assemblies with randomly distributed initial parameters by the Monte Carlo method are presented as well as the thermomechanical analysis of the temperature field in the fuel assemblies during the campaign. An idea about the equilibrium configuration of a rod bundle in a hexagonal jacket during irradiation, the stress–strain state of an individual fuel rod and a fuel assembly jacket is obtained. The tasks of further investigations discussed.

Exploring the Strategies for Indicating Research Gaps Used by Authors in English Education Research Article Introductions

The trend of topics in language education research is affected by how authors convince readers about the issues being discussed. However, the persistence of the topic is not based on the number of scholars who have conducted the research, for instance, collaborative writing topics, but it focuses more on the newness to be contributed to the advancement of knowledge by indicating research gaps. Therefore, this qualitative study, which is specified into genre analysis, aims to describe the strategies for indicating research gaps and the area of gaps that are still needed to be fulfilled in the research of collaborative writing. A corpus consisting of 20 research article introductions (RAIs) published in highly reputable journals with high-impact factors was compiled and subjected to analyze, respectively (i.e., using the frameworks of Lim, 2012 and Ewijk, 2018) the types of research gap strategies and the areas of gaps that have been focused on by the authors. The findings show that the strategy of stating the absence of a specific area in the research of collaborative writing is employed in a vast majority (45.45%). Besides, the area of impact is found as the promising area of gap (occurred 24 times) that the authors tend to focus on. The pedagogical implications of this study are also discussed in this article.

Effect of gap size on the regeneration in Larix principis-rupprechtii plantation.

We conducted a survey on seedlings (height <1 m) and saplings (height ≥1 m, diameter at breast height <5 cm) in 20 gaps of Larix principis-rupprechtii plantations on Guandi Mountains, Shanxi to analyze regene-ration density, growth indicators, and spatial distribution of L. principis-rupprechtii seedlings and saplings under four gap sizes (<60 m2, 60-120 m2, 120-180 m2, and ≥180 m2). The results showed that growth indicators (ground diameter, height) of seedlings and saplings and regeneration density of seedlings were highest in small gaps (14-60 m2). The sapling regeneration density was highest in medium gaps (60-120 m2), and sapling density exceeded seedling density in each size category. L. principis-rupprechtii seedlings and saplings exhibited favorable regeneration in small and medium gaps, while large gaps (120-180 m2) and extra-large gaps (≥180 m2) were unfavorable for L. principis-rupprechtii regeneration. L. principis-rupprechtii seedlings and saplings were mainly distributed within the canopy projection area and along the edge of canopy gap area. Controlling gap size within the range of 14-120 m2 through artificial interventions, such as planting and thinning, could promote the regeneration of L. principis-rupprechtii.

Environmental Education for Sustainable Development: A Bibliometric Review of Curriculum Design and Pedagogical Approaches

Environmental education plays a pivotal role in fostering a sustainable future by equipping individuals with the knowledge, skills, and attitudes needed to address complex environmental challenges. This research presents a comprehensive bibliometric review of the literature on environmental education for sustainable development, with a specific focus on curriculum design and pedagogical approaches. The analysis encompasses a wide range of scholarly articles published between 1961 and 2023, providing valuable insights into the current state of research in this field. Furthermore, the research employs VOSviewer, a bibliometric software, to analyze co-citation and bibliographic coupling networks, identifying influential authors, prominent journals, and emerging trends within the field. The most frequent and fewer occurring keywords are compared to highlight central concepts and potential areas for further research. The results of this study contribute to a comprehensive understanding of the diverse themes, effective practices, and influential contributors in environmental education for sustainable development. By identifying key areas of focus and research gaps, educators, policymakers, and researchers can design targeted interventions and initiatives that promote environmental literacy, responsible behavior, and sustainable practices among learners. Ultimately, this research seeks to advance the field of environmental education and empower individuals to become active stewards of the environment, shaping a more sustainable and resilient future for all.

Nitrogen addition changes the canopy biological characteristics of dominant tree species in an evergreen broad-leaved forest

Many studies have focused on the impact of nitrogen deposition on plants, but due to technical limitations, research on the responses of forest canopy to manipulated nitrogen deposition is relatively scarce. Based on a canopy nitrogen addition (CN) platform, this study used laboratory analysis and unmanned aerial vehicle (UAV) observations to assess the impact of CN on the canopy traits of dominant tree species (Engelhardia roxburghiana, Schima superba, and Castanea henryi) in an evergreen broad-leaved forest in China. The results showed that nitrogen application at 25 kg N ha−1 y−1 (CN25) and 50 kg N ha−1 y−1 (CN50) significantly increased the actual net photosynthetic rate (An) of all the three tree species. CN25 significantly increased superoxide dismutase (SOD), catalase (CAT), and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activities in C. henryi. CN50 significantly increased the leaf area of all the three tree species and significantly reduced the leaf thickness of C. henryi, and significantly increased the POD and Rubisco activities in S. superba and C. henryi. CN significantly changed the number of forest gaps, but did not significantly change the area of forest gaps within the sample plots. CN25 significantly decreased the vertical projection area but increased the canopy flowering coverage of S. superba in dominant directions. CN25 and CN50 significantly increased the flowering coverage of C. henryi in favorable directions. It is found that under long-term (10-year) nitrogen addition, the balance between carbon fixation and antioxidant defense functions of E. roxburghiana may be broken down, but the carbon assimilation, antioxidant capacity and reproduction potential of S. superba and C. henryi may be well coordinated, which will have a potential impact on the species composition and ecological functions of the evergreen broad-leaved forest. This study may also provide scientific basis for forest management in the context of enhanced atmospheric nitrogen deposition.

Effects of the inhomogeneous microstructures on buffer layer ablation failure in high voltage cables

In recent years, growing attention has been paid to the buffer layer ablation failure in high voltage cables. The buffer layer was always regarded as a homogeneous material in previous studies, while in this paper, the effects of its structural inhomogeneity on failure is found unneglectable. The buffer layer is recognized to be a porous material comprising fibers and air pores through microscopic characterization. Its porosity is measured to be 85% by testing mercury intrusion porosimetry. Especially, some small fiber protrusions are observed on the surface of buffer layer, which are categorized and named as tip protrusions and arched protrusions. Subsequently, the influence of these fiber protrusions is investigated by quantitatively proposing their geometric models. The electric field distortion is observed at the fiber regions after finite element simulation. Under the extreme circumstances when the tip protrusions are vertical and close to the central area of air gap, the maximum electric field at tip site can reach to 28.5 kV/mm, which is 9.5 times of the breakdown threshold of air. And the maximum electric field of arched protrusions region can reach to 5.94 kV/mm, which is more moderate but still higher than the threshold. Therefore, it is demonstrated that the breakdown of air gap inner cables can be induced by the inhomogeneous fiber protrusions.

A 4-Week Straw Phonation in Water Exercise Program for Aging-Related Vocal Fold Atrophy.

This study evaluated the efficacy of a 4-week straw phonation in water (SPW) exercise program on aging-related vocal fold atrophy (VFA), with a secondary objective to examine the immediate effects of SPW exercises. Thirty-eight older adults aged 60 years and above formally diagnosed with aging-related VFA were randomly assigned into an experimental group undergoing SPW exercises with an 8-cm depth of straw submersion into water for 4 weeks plus vocal hygiene practice (n = 20), and a control group with only vocal hygiene practice (n = 18). Outcome measures included laryngeal endoscopic measures of glottal gap, auditory-perceptual ratings of voice quality, acoustic measures, aerodynamic measures, and standardized self-assessment questionnaire scores. An additional round of acoustic and aerodynamic assessment following 20 min of SPW exercises was conducted to examine the immediate effects. Significant improvements in normalized glottal gap area, perceptual rating of breathiness, smoothed cepstral peak prominence, harmonics-to-noise ratio (HNR), mean oral airflow, subglottal pressure and laryngeal airway resistance at comfortable loudness, Voice-related Quality of Life scores, and Chinese Vocal Fatigue Index Factor 3 scores were observed in the experimental group relative to the control group. There were also significant immediate effects for HNR, mean oral airflow, subglottal pressure, and laryngeal airway resistance. These findings suggested significant immediate improvements in vocal function following SPW exercises, with additional significant improvements in vocal function as well as significant improvements in quality of life following the 4-week SPW exercise program. Further studies with more long-term follow-up are recommended to better understand the efficacy of SPW exercises with deep levels of straw submersion into water as an effective clinical option for the management of hypofunctional dysphonia associated with aging-related VFA.

The application of gap planting technology to rehabilitate degraded natural forest

In 2020 degraded forests in Indonesia reached 33.4 million ha. These forests must be rehabilitated. The purpose of this research was to show the application of gap planting technology to rehabilitate degraded natural forests. This improvement of forest regeneration methods by planting local intolerant tree species in gaps area was used. Artificial gaps area was designed and it’s location was adjusted to the topography and forest cover. The size of each gap area is 2,000 m2. The ratio of total gaps area to total natural forests area was about four to six. Open areas, soil density, forest fire risk, working time and cost of gap planting, and tree growth were studied. The results showed that after the gap planting: forest cover consists of 37.43% gap planting area and 62.57% natural forest area; forest soil is not compacted; the fire hazard rating in the gap and natural forests is low. Moreover, it is cost-effective and has positive impacts such as job creation for local communities and a productivity increase of rehabilitated forests. It is concluded that the gap planting technology was environment friendly technology, and it is recommended to be used for rehabilitation of degraded forests in Indonesia.