Some characteristics of plastic streamer tubes
Nuclear instruments and methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment/Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/1985
Journal Article
Experimental results are reported on the angular distributions of the gamma rays emitted in the planar channeling of 10-GeV positrons in a silicon single crystal 113 microns thick. The ...spectral-angular emission density of the gamma rays emitted at various angles from the crystal is plotted against the energy.
Silicon (Si) biogeochemical cycling is beneficial for crop productivity and carbon (C) sequestration in agricultural ecosystem, thus offering a nonnegligible role in alleviating global warming and ...food crisis. Compared with other crops, rice plants have a greater quantity of phytolith production, because they are able to take up a lot of Si. However, it remains unclear on Si supply capacity of paddy soils across the world, general rice yield-increasing effect after Si fertilizer addition, and factors affecting phytolith production and potential of phytolith C sequestration in paddy fields. This study used a meta-analysis of >3500 data from 87 studies to investigate Si supply capacity of global paddy soils and elaborate the benefits of Si regarding rice productivity and phytolith C sequestration in paddy fields. Analytical results showed that the Si supply capacity of paddy soils was insufficient in the major rice producing countries/regions. Dealing with this predicament, Si fertilization was an effective strategy to supply plant-available Si to improve rice productivity. Our meta-analysis results further revealed that Si fertilization led to the average increasing rate of 36 % and 39 % in rice yield and biomass, which could reach up to 52 % and 46 % with the increasing doses of Si fertilizer, respectively. Especially, this strategy also improved the potential of phytolith C sequestration through the increased phytolith content and rice biomass, despite that this potential might have a decline in old paddy soils (≥ 7000 year) compared to in young paddy soils (≤ 1000 year) due to the slow migration and dissolution of phytoliths at millennial scale. Our findings thus indicate that a deep investigation on the benefits of Si in agroecosystem will further improve our understanding on regulating crop production and the potential of biogeochemical C sequestration within phytoliths in global cropland.
Display omitted
•Si supply capacity of paddy soils throughout the world is not optimistic.•Si fertilization increases 36 % of rice yield and 39 % of rice biomass, respectively.•The threshold value of Si fertilization-induced increasing rate is 52 % for rice yield.•The threshold value of Si fertilization-induced increasing rate is 46 % for rice biomass.•Si fertilization enhances PhytOC sink via increasing phytolith content and biomass.
In this paper, we propose a new method for scheduling of maintenance operations in a manufacturing system using the continuous assessment and prediction of the level of performance degradation of ...manufacturing equipment, as well as the complex interaction between the production process and maintenance operations. Effects of any maintenance schedule are evaluated through a discrete-event simulation that utilizes predicted probabilities of machine failures in the manufacturing system, where predicted probabilities of failure are assumed to be available either from historical equipment reliability information or based on the newly available predictive algorithms. A Genetic Algorithm based optimization procedure is used to search for the most cost-effective maintenance schedule, considering both production gains and maintenance expenses. The algorithm is implemented in a simulated environment and benchmarked against several traditional maintenance strategies, such as corrective maintenance, scheduled maintenance and condition-based maintenance. In all cases that were studied, application of the newly proposed maintenance scheduling tool resulted in a noticeable increase in the cost-benefits, which indicates that the use of predictive information about equipment performance through the newly proposed maintenance scheduling method could result in significant gains obtained by optimal maintenance scheduling.
Carbon nanofibers are a class of lightweight, high-performance composite materials. Their bespoke porous defects, intricate multiporous channel topography, and substantial specific surface area ...render them instrumental in addressing many pivotal challenges within the environmental and energy sectors. Despite the escalating research dedicated to the applications of nanofibers across diverse fields, scant attention has been accorded to the disposal of waste fibers. The paradigms for the recovery and subsequent reutilization of these high-caliber carbon nanofibers remain unformulated, culminating in substantial wastage and concomitant environmental degradation annually. This study highlights the urgency of recycling these fibers, summarizing the importance of recycling, relevant policies, and current methodologies while critiquing the field's status quo. Traditional recovery techniques are insufficient for these premium nanofibers, necessitating innovative, efficient recycling strategies. Emphasizing the necessity for original recycling technologies, we advocate for conceptualizing degradable fibers driven by reversible chemical bonds, transitioning towards biomass-derived nanofibers, and a fundamental reorientation to perceive waste as a valuable asset. Future strategies should focus on enhancing recovery rates and maintaining fiber functional structure, with policy support and increased environmental awareness crucial for advancement. Our insights aim to guide further studies towards efficient and sustainable solutions for carbon nanofiber management.
Carbon nanofibers are a class of lightweight, high-performance composite materials.
Abstract Litter decomposition is a key ecological process that determines carbon (C) and nutrient cycling in terrestrial ecosystems. The initial concentrations of C and nutrients in litter play a ...critical role in this process, yet the global patterns of litter initial concentrations of C, nitrogen (N) and phosphorus (P) are poorly understood. We employed machine learning with a global database to quantitatively assess the global patterns and drivers of leaf litter initial C, N and P concentrations, as well as their returning amounts (i.e. amounts returned to soils). The medians of litter C, N and P concentrations were 46.7, 1.1, and 0.1%, respectively, and the medians of litter C, N and P returning amounts were 1.436, 0.038 and 0.004 Mg ha −1 year −1 , respectively. Soil and climate emerged as the key predictors of leaf litter C, N and P concentrations. Predicted global maps showed that leaf litter N and P concentrations decreased with latitude, while C concentration exhibited an opposite pattern. Additionally, the returning amounts of leaf litter C, N and P all declined from the equator to the poles in both hemispheres. Synthesis : Our results provide a quantitative assessment of the global concentrations and returning amounts of leaf litter C, N and P, which showed new light on the role of leaf litter in global C and nutrients cycling.
A nonvolatile memory (NVM) based on an amorphous-indium-gallium-zinc oxide (a-IGZO) thin-film transistor (TFT) with defect-engineered gate insulator was demonstrated. The gate insulator was a ...blocking alumina/storage alumina/tunneling alumina stack structure, which was simply assembled in a single atomic layer deposition step. The memory device showed a positive shift of threshold voltage as large as 14.4 V after +20 V, 1 s programming. In contrast, the memory erasing was not sensitive to negative gate voltage in the dark. Once programmed, the memory can only be light erased. Furthermore, the light combined with a negative bias improved the erasing speed effectively. In addition, a 10-year memory window as large as 7.5 V was extrapolated at room temperature with a charge loss of 34.7%. Based on the observation of blisters in the storage alumina layer after high temperature annealing, Fourier transform infrared spectroscopy measurement and first-principles calculations, the high electron storage capacity can be attributed to the deep defect levels in the storage alumina layer, which were originated from hydrogen impurity. This a-IGZO TFT charge trapping NVM with high performance and simple process is a candidate device for the application of fully functional transparent system on panel.
The initial concentration of litter nutrient not only affects the following decomposition process but also determines the quantities of nutrients returned to the soil. The aim of this study is to ...assess the global patterns and driving factors of three macronutrients, namely potassium (K), calcium (Ca) and magnesium (Mg), in freshly fallen litter.
By synthesizing 5861 data points extracted from 584 publications, we quantitatively evaluated the concentrations of litter K, Ca and Mg in different litter types, life forms, taxonomic divisions and mycorrhizal associations. Also, using the machine learning method, we predicted their global patterns in forests, grasslands and shrublands.
We found that (1) mean K, Ca and Mg concentrations ranged from 2.63 to 6.23, 1.05 to 11.50 and 0.20 to 2.74 g/kg, respectively, across different litter types; (2) the initial nutrients of the litter were significantly affected by plant functional types (e.g. life form, taxonomic division and mycorrhizal association), climate (e.g. isothermality, mean diurnal range, annual evapotranspiration and precipitation seasonality) and soil properties (e.g. pH, exchangeable Ca concentration and water content), with a higher litter K concentration of herbaceous plants, higher K, Ca and Mg concentrations from angiosperms and higher K and Mg concentrations from plants associated with arbuscular mycorrhiza (AM) fungi; and (3) the predicted leaf litter K, Ca and Mg concentrations were lower in high‐latitude regions compared with those in low‐ and/or mid‐latitude regions.
Our study provides a globally comprehensive analysis on the patterns and driving factors of three important macronutrients in freshly fallen litter, contributing to a better understanding of their role in the decomposition process of litter, as well as the associated biogeochemical cycles under the future climate change scenario.
Read the free Plain Language Summary for this article on the Journal blog.
Read the free Plain Language Summary for this article on the Journal blog.
PDF
