Enabling online geospatial isotopic model development and analysis

In recent years, there has been a rapid growth in the amount of environmental data collected over large spatial and temporal scales. It presents unprecedented opportunities for new scientific discovery, while in the same time poses significant challenges to the research community on how to effectively identify and integrate these datasets into their research models and tools. In this paper, we describe the design and implementation of IsoMAP- a gateway for Isoscapes (isotopic landscapes) modeling, analysis and prediction. IsoMAP provides an online workspace that helps researchers access and integrate a number of disparate and diverse datasets, develop Isoscapes models over selected spatio-temporal domains using geo-statistical algorithms, and predict maps for the stable isotope ratios of water, plants, and soils. The IsoMAP system leverages the computation resources available on the TeraGrid to perform geospatial data operations and geostatistical model calculations. It builds on a variety of open source technologies for GIS, geospatial data management and processing, grid computing, and gateway development. The system was successfully used to teach a tutorial in the 2011 conference on the Roles of Stable Isotopes in Water Cycle Research. A post-tutorial survey was conducted. We review the users ’ feedback and present a future development plan based on that

Study on Re-concentration of Flotation Tailings in Gongchangling Iron Plant

Pre-separation test of grinding-high intensity magnetic separation-medium magnetic separation was carried out on the flotation tailings of Gongchangling hematite. The iron grade of magnetic separation rough concentrate obtained by pre-separation is 41.71%，yield is 33.62% and iron recovery is 84.21%. The effects of two flotation processes, flotation column and flotation machine roughing, on the quality improvement of pre-concentration coarse concentrate were compared. The single factor test results show that the optimal working parameters of flotation column are feeding pressure 0.08 Mpa and aeration 0.05 m3/h. Through the closed-circuit test of one roughing, one cleaning and one scavenging process made of flotation column and two flotation units，the technical indexes of 18.89% concentrate mineral rate, 65.29% grade and 74.07% iron recovery can be obtained, which are 0.27 percentage points and 2.61 percentage points higher than that of single flotation machine process, respectively

The effect of various surfactants on fatty acid for apatite flotation and their adsorption mechanizm

The synergistic effect of surfactants, i.e., Tween-80 (polyethylene glycol sorbitan monooleate), Span-80 (sorbitanoleate), and MES (fatty acid methyl ester sulfonates), on fatty acid collectors were investigated using single mineral flotation experiments, surface tension measurement, Fourier transform infrared spectrum, and contact angle measurements. The single mineral flotation experiments showed that it was possible to efficiently separate apatite from magnetite, quartz, and biotite by mixing fatty acids with surfactants. The surface tension measurement showed that the surfactants could significantly reduce the surface tension and Critical Micelle Concentration (CMC) of fatty acids. Fourier transform infrared spectroscopy analysis indicated that all of the surfactants did not react with the fatty acids, but only physically adsorbed on the surface of apatite, thus promoting the chemical adsorption of fatty acids on apatite. However, the surfactant chemisorbed on magnetite and competing with a fatty acid, which led to a decrease in the flotation recovery. The results for contact angle measurement showed that the contact angle difference between apatite and magnetite increased with the addition of surfactant, and resulted in an efficient separation

Prediction of soil moisture using BiGRU-LSTM model with STL decomposition in Qinghai–Tibet Plateau

Ali Network data based on the Qinghai-Tibetan Plateau (QTP) can provide representative coverage of the climate and surface hydrometeorological conditions in the cold and arid region of the QTP. Among them, the plateau soil moisture can effectively quantify the uncertainty of coarse resolution satellite and soil moisture models. With the objective of constructing an “end-to-end” soil moisture prediction model for the Tibetan Plateau, a combined prediction model based on time series decomposition and a deep neural network is proposed in this article. The model first performs data preprocessing and seasonal-trend decomposition using loess (STL) to obtain the trend component, seasonal component and random residual component of the original time series in an additive way. Subsequently, the bidirectional gated recurrent unit (BiGRU) is used for the trend component, and the long short-term memory (LSTM) is used for the seasonal and residual components to extract the time series information. The experiments based on the measured data demonstrate that the use of STL decomposition and the combination model can effectively extract the information in soil moisture series using its concise and clear structure. The proposed model in this article has a stable performance improvement of 5–30% over a single model and existing prediction models in different prediction time domains. In long-range prediction, the proposed model also achieves the best accuracy in the shape and temporal domains described by using dynamic time warping (DTW) index and temporal distortion index (TDI). In addition, the generalization performance experiments show that the combined method proposed in this article has strong reference value for time series prediction of natural complex systems

Research on specific identification method of substances through terahertz metamaterial sensors

In this work, a strategy to specifically identify substances through correlating the substance fingerprint peak with the resonant frequency shift of the metamaterial sensors has been presented and demonstrated experimentally. Three metamaterial sensors with different resonance frequencies were fabricated by ultrafast laser direct writing, and they all have good sensing performance. Due to the different matching degrees between the sensor resonance peak and the substance fingerprint peak, different frequency shifts of the sensor resonance peak were obtained. The better the fingerprint peak matches the sensor resonance peak, the greater the shift of the sensor resonance peak. On the contrary, the smaller shift will be obtained. Through this method, the correlation between the resonant frequency shift of the sensor and the fingerprint peak of the substance is developed. Thus, within a certain range of some unknown substances, the fingerprint peak positions of the substances can be deduced through the frequency shifts of the sensor. This phenomenon was used for the specific identification of the substances. This study provides a new idea for the specific detection of the substances by the metamaterial sensor

Numerical modeling of the stress-strain state of peripheral massif in the vicinity of mine workings

In the process of numerical studies, the stress-strain state of the rock massif around the mine working driven at a depth of 600 m was determined. The article presents the analysis of the distribution of total vertical and horizontal stresses isolines in the working roof, as well as the ratio of the residual strength of rocks to the initial. The influence of the roof bolting on the displacement of working contour was established. Dangerous zones in the near-contour rocks of preparatory working were identified. The maximum exposure area of unsecured part of the roof during driving the workings in seam 3-3a was established

Research on the mechanism of a mixed collector onto magnesite surface to improve the flotation separation of magnesite from hornblende

Low-grade magnesite is not effectively used mainly due to high silicon content, especially the separation of magnesite and hornblende. In this research, a novel mixture of sodium oleate and dodecyl phosphate collector was used to increase the flotation difference between magnesite and hornblende. Artificially mixed mineral concentrates grade 47.10% (MgO content) concentrate recovery of 84.45% was obtained by micro flotation test, the results showed that the mixed collector of sodium oleate and dodecyl phosphate played a better selective promotion role in the flotation of magnesite. The interaction mechanism of this mixed collector with hornblende and magnesite surfaces was investigated using Fourier transform infrared spectroscopy (FTIR), zeta potential, and X-ray photoelectron spectroscopy (XPS), which showed that the mixed collector in terms of magnesium selection was mainly adsorbed on these magnesium sites of magnesite, and the surface of magnesite thus became hydrophobic, allowing magnesite to float and separate from hornblende

ZHT: A light-weight reliable persistent dynamic scalable zero-hop distributed hash table

Abstract — This paper presents ZHT, a zero-hop distributed hash table, which has been tuned for the requirements of high-end computing systems. ZHT aims to be a building block for future distributed systems, such as parallel and distributed file systems, distributed job management systems, and parallel programming systems. The goals of ZHT are delivering high availability, good fault tolerance, high throughput, and low latencies, at extreme scales of millions of nodes. ZHT has some important properties, such as being light-weight, dynamically allowing nodes join and leave, fault tolerant through replication, persistent, scalable, and supporting unconventional operations such as append (providing lock-free concurrent key/value modifications) in addition to insert/lookup/remove. We have evaluated ZHT's performance under a variety of systems, ranging from a Linux cluster with 512-cores, to an IBM Blue Gene/P supercomputer with 160Kcores