Ultrasonic and CT scanning analysis of coal-rock mass under the primary bedding structure

In order to study the influence of the primary bedding structure on wave velocity and mechanical properties of coal-rock mass, multilayer and multi-directional ultrasonic and CT scanning tests were carried out in laboratory. It also aims to improve the accuracy, rapidity and convenience of obtaining the wave velocity and mechanical parameters of coal-rock mass in laboratory. Based on the ultrasonic test, the characteristics of wave velocity and wave velocity ratio at different layers of coal-rock mass under the primary bedding dip angle were obtained. Combined with CT scanning and 3D reconstruction technology, the calculation method of CT gray mean value in different layers was proposed by using the data of the gray frequency of coal and rock. And the variation law of gray value and coal and rock content of coal-rock mass in different layers under different primary bedding dip angle was obtained. Meanwhile, the relationships between CT gray mean value and wave velocity, mechanical parameters of coal-rock mass were established. Considering the effect of bedding dip angle and the content of coal and rock, the calculation model of longitudinal wave velocity of coal-rock mass was constructed. Then the correctness of the model is verified by comparing the test data. The results show that: ① the wave velocity and wave velocity ratio of coal-rock mass with primary bedding are linearly related to bedding dip angle; with the increase of bedding dip angle, the longitudinal wave velocity of coal-rock mass decreases linearly, while the distribution range of wave velocity ratio expands; ② the mean wave velocity of CT is linearly correlated under different bedding dip angles, and the wave velocity of coal-rock mass increases linearly with the increases of CT gray mean value; ③ the density of coal-rock mass increases linearly with the increase of CT gray mean value, the dynamic elastic modulus and shear modulus of coal-rock mass have third order polynomial relationships with the mean value of CT gray level, and they tend to increase with the increase of the mean value of CT gray level; ④ compared with the bedding dip angle, the wave velocity of coal-rock mass is more sensitive to the coal and rock content, and the wave velocity changes largest during the content of coal and rock similar

Threats to the Soil Resource Base of Food Security in China and Europe. A report from the Sino-EU Panel on Land and Soil

To secure adequate food supply is the major challenge for humanity in the 21st century. Growing world population and its urbanization put pressure on this basic need, which is further threatened by the constant loss of fertile land. The assessment of sustainability of food supply under increasing pressure on land resources has been selected as one of the most important priority topics of the activities of Sino-EU Panel on Land and Soil (SEPLS). The Panel has performed a number of related researches and discussed the results on a scientific seminar in January 2012 in Nanjing, China. This report is an output of this seminar with a summary of the structured discussions on the below issues. 1. Urban and peri-urban development (soil sealing and loss of land functions) Urbanization and the linked spread of infrastructural development mean sealing of soil surfaces. Soil sealing is the most rapidly growing limitation for soil functions (including biomass production function) both in China and Europe. Soil sealing in China has been taking dramatic degree in the last two decades and the process is estimated to continue in the coming period as well. While urban and peri-urban development is looked as a necessity for social development, its negative effect on natural resources are inevitable. 2. Land degradation Despite the widely recognized importance of land degradation in the unsustainability of economic development and implementation of various policies to halt degradation (e.g. green for grain programme in China; cross-compliance measures in the EU), loss of land productivity by degradation is an ongoing process both in China and the EU. Major forms of soil degradation (erosion, desertification, landslides etc.) are similar in both regions. Assessment of the causes and consequences of soil degradation processes in relation to policy actions is highlighted among the priorities of the SEPLS. 3. Intensive agriculture and multi-function management of land resources Intensification and extensification in agriculture can be considered as the main changes in land use in rural areas in both EU and China. While agricultural intensification is one of the greatest threats to the soil and environment and then hampers the sustainable development of agriculture and food security. To meet this challenge, sustainable management of multi-functionality of land resources is undoubtedly an effective strategy, in which the EU has a good expertise. Bilateral exchange of the experience and knowledge benefits the sustainable management of land resources.JRC.H.5-Land Resources Managemen

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Cluster Anti-Synchronization of Complex Networks with Nonidentical Dynamical Nodes

This paper investigates a new cluster antisynchronization scheme in the time-varying delays coupled complex dynamical networks with nonidentical nodes. Based on the community structure of the networks, the controllers are designed differently between the nodes in one community that have direct connections to the nodes in other communities and the nodes without direct connections with the nodes in other communities strategy; some sufficient criteria are derived to ensure cluster anti-synchronization of the network model. Particularly, the weight configuration matrix is not assumed to be irreducible. The numerical simulations are performed to verify the effectiveness of the theoretical results

Algorithms for the Shortest Path Improvement Problems under Unit Hamming Distance

In a shortest path improvement problem under unit Hamming distance (denoted by SPIUH), an edge weighted graph with a set of source-terminal pairs is given; we need to modify the lengths of edges by a minimum cost under unit Hamming distance such that the modified distances of the shortest paths are upper bounded by given values. The SPIUH problem on arborescent network is formulated as a 0-1 integer programming model. Some strongly polynomial time algorithms are designed for the problems on some special arborescent networks. Firstly, two greedy algorithms are proposed for problems on chain networks and special startree networks, respectively. Secondly, a strongly polynomial time algorithm is presented for the problem with a single source and constrained paths. Finally, a heuristic algorithm and its computational experiments are given for the SPIUH problem on general graphs

Algorithms for the Shortest Path Improvement Problems under Unit Hamming Distance

In a shortest path improvement problem under unit Hamming distance (denoted by SPIUH), an edge weighted graph with a set of source-terminal pairs is given; we need to modify the lengths of edges by a minimum cost under unit Hamming distance such that the modified distances of the shortest paths are upper bounded by given values. The SPIUH problem on arborescent network is formulated as a 0-1 integer programming model. Some strongly polynomial time algorithms are designed for the problems on some special arborescent networks. Firstly, two greedy algorithms are proposed for problems on chain networks and special star-tree networks, respectively. Secondly, a strongly polynomial time algorithm is presented for the problem with a single source and constrained paths. Finally, a heuristic algorithm and its computational experiments are given for the SPIUH problem on general graphs

Multi-Physical Coupling Field of a Permanent Magnet Linear Synchronous Generator for Wave Energy Conversion

Permanent Magnet Linear Synchronous Generators (PMLSG) has high power density and high efficiency, which is always employed in industrial application field. However, as temperature increases, it is easy to cause demagnetization of the permanent magnet, and the applications of PMLSG is limited. In this paper, a PMLSG is optimized which is used in a low speed power generation system. Firstly, a multi-physical coupling field system is described, and introduced the main factors which affecting the design of the PMLSM. Secondly, a multi-physics optimization method based on Genetic Algorithm (GA) is to improve the power density and efficiency. At the same time reduce the material cost of the generator. The thermal model is established and analysis the losses of PMLSG. The conductive heat transfer coefficient is calculated. Then, a Finite Element Analysis (FEA) model is established, and the electromagnetic properties of PMLSG were analyzed. The results of the electromagnetic field calculation are imported into the transient thermal analysis model by FEA, and the temperature of each part for PMLSG are calculated. Finally, an experimental test platform is built for verifying the correctness of the analysis

Precipitation amount and event intervals interact to change plant diversity during dry years in a desert shrubland

Variations in species diversity and soil properties in response to future climate change is a key focus area in ecological research. The influence of precipitation amount on plant community diversity and soil properties, in sandy desert ecosystems, is poorly studied. We chose the Artemisia ordosica community to examine how diversity, and the physical and chemical properties of soil vary in response to changes in precipitation. An in situ experimental platform was used to simulate total monthly precipitation at specific intervals in a desert-grassland region of northern China. The influence of precipitation on the community was investigated using three precipitation amount levels and two intervals. The relative density, coverage, and frequency of species in each experimental quadrat was analyzed for evaluating the community structure. Results showed that variability in precipitation amounts and intervals altered the species diversity in the A. ordosica communities. Increased precipitation amount enhanced whole community’s species diversity via improving the richness of perennial forbs. Lengthening the precipitation intervals enhanced whole community’s species diversity in the context of low precipitation amount but reduced species diversity in high precipitation amount condition. The precipitation patterns affected community species composition and diversity mainly by controlling soil moisture, secondly by changing the nitrogen and organic matter content of the surficial soils. This study revealed that effects of precipitation interval on the species diversity depended on annual precipitation amount and offer an innovative insight to evaluating the succession of desert ecosystems in the context of precipitation change in the future

Parameter-Efficient Model Adaptation for Vision Transformers

In computer vision, it has achieved great transfer learning performance via adapting large-scale pretrained vision models (e.g., vision transformers) to downstream tasks. Common approaches for model adaptation either update all model parameters or leverage linear probes. In this paper, we aim to study parameter-efficient model adaptation strategies for vision transformers on the image classification task. We formulate efficient model adaptation as a subspace training problem and perform a comprehensive benchmarking over different efficient adaptation methods. We conduct an empirical study on each efficient model adaptation method focusing on its performance alongside parameter cost. Furthermore, we propose a parameter-efficient model adaptation framework, which first selects submodules by measuring local intrinsic dimensions and then projects them into subspace for further decomposition via a novel Kronecker Adaptation method. We analyze and compare our method with a diverse set of baseline model adaptation methods (including state-of-the-art methods for pretrained language models). Our method performs the best in terms of the tradeoff between accuracy and parameter efficiency across 20 datasets under the few-shot setting and 7 image classification datasets under the full-shot setting