Control system of spontaneous combustion in coal gangue dumps – a case study at Yuquan coal mine in China

Spontano zapaljenje na odlagalištima jalovine uglja dovodi do zagađenja okoliša i oštećenja ekosustava i ljudskog zdravlja. Voditelji ugljenokopa obično ne poduzimaju učinkovite mjere sprečavanja spontanog zapaljenja zbog nepravovremenog otkrivanja mjesta izbijanja spontanog zapaljenja. Zbog toga je u ovom radu dizajniran i konstruiran sustav kontrole spontanog zapaljenja na odlagalištima jalovine. Taj se sustav sastoji od sustava za otkrivanje područja spontanog zapaljenja, pokretnog sustava za prevenciju i gašenje spontanog zapaljenja primjenom tekućeg ugljičnog dioksida (LCD - Liquid Carbon Dioxide) i sustava za provjeru učinka spontanog zapaljenja u odlagalištu jalovine. Prvo je sustavom otkrivanja otkriveno područje spontanog zapaljenja na odlagalištu, Zatim je u zapaljeno područje uštrcan LCD pomoću opreme za uštrcavanje kako bi se temperatura u odlagalištu smanjila ispod točke zapaljenja ugljene jalovine i kako bi se kisik izbacio iz odlagališta. Konačno, sustavom za provjeru učinkovitosti ispitali su se učinci dvaju sustava. Spontano zapaljenje na odlagalištima jalovine provjereno je na analizi slučaja u Yuquan rudniku. Rezultati pokazuju da su koncentracije plinova CO i H2S na odlagalištu jalovine ugljenokopa Yuquan ispod 24 i 6,6 ppm, a unutarnja temperature je ispod 70 °C. Cijena po kvadratnom metru sustava kontrole spontanog zapaljenja iznosi približno $8. Prema tome, predloženim se kontrolnim sustavom može ekonomično i učinkovito nadgledati spontano zapaljenje na odlagalištima jalovine uglja, stoga i spriječiti zagađenje okoliša.Spontaneous combustion in coal gangue dumps leads to pollution in the environment and damages ecosystem and human health. Mine operators usually fail to take effective measures against spontaneous combustion because of the inaccurate detection of the location of spontaneous combustion bursts. To address this issue, a control system of spontaneous combustion in coal gangue dumps was designed and constructed in this study. The control system is composed of a detection system of spontaneous combustion areas, a mobile prevention and extinguishing system of spontaneous combustion using liquid carbon dioxide (LCD), and an effect-checking system of spontaneous combustion in coal gangue dump. First, the detection system was used to detect the spontaneous combustion areas in the coal gangue dumps. LCD was then injected into the combustion areas with its pressure injection equipment to lower the temperature in the coal gangue dumps below the ignition point of coal gangue and to force oxygen out of the dumps. Finally, the effect-testing system was used to test the effects of the two systems. The spontaneous combustion in coal gangue dumps was controlled through a case study at Yuquan coal mine. Results show that the concentrations of index gases CO and H2S in the coal gangue dumps of Yuquan coal mine are below 24 and 6,6 ppm, and the internal temperature is below 70 °C, The cost per square meter of the control system of spontaneous combustion is approximately$8. Therefore, the proposed control system can economically and effectively control spontaneous combustion in coal gangue dumps, thereby preventing pollution in the environment

Separation of bastnäsite from fluorite using ethylenediamine tetraacetic acid as depressant

Bastnäsite is an important mineral resource in the production of rare earth materials and is usually beneficiated by flotation. The flotation of bastnäsite is problematic due to the competitive adsorption of hydroxamate collector on bastnäsite and its associated calcium-bearing gangue minerals such as fluorite. One strategy to solve this problem is to use effective depressants to depress the gangue minerals. However, the current depressants all have some drawbacks. In this study, the effect of ethylenediamine tetraacetic acid (EDTA) as a depressant was tested in the flotation of single mineral of bastnäsite and fluorite and their mixture. The mechanism underpinning the role of EDTA was investigated through theoretical thermodynamic calculation, zeta potential and X-ray photoelectron spectroscopy (XPS) measurements. The results show that fluorite was significantly depressed, while the flotation of bastnäsite was almost unaffected when EDTA was present. The separation index between bastnäsite and fluorite increased from 1.18 to 12.66 with the increase of EDTA concentration from 0 to 7.79 kg/t. It was found that EDTA could dissolve the chemically adsorbed octyl hydroxamic acid (OHA) on fluorite through the formation of soluble Ca-EDTA complexes, whereas the chemically adsorbed OHA on bastnäsite was more stable and could not be transformed into Ce-EDTA spontaneously. Therefore, the flotation of fluorite was selectively depressed by EDTA. The results show that EDTA was a promising depressant for fluorite gangue mineral in bastnäsite flotation

Two-photon excited fluorescence emission from hemoglobin

Hemoglobin, one of the most important proteins in blood, is responsible for oxygen transportation in almost all vertebrates. Recently, we discovered two-photon excited hemoglobin fluorescence and achieved label-free microvascular imaging based on the hemoglobin fluorescence. However, the mechanism of its fluorescence emission still remains unknown. In this work, we studied the two-photon excited fluorescence properties of the hemoglobin subunits, heme/hemin (iron (II)/(III) protoporphyrin IX) and globin. We first studied the properties of heme and the similar spectral and temporal characteristics of heme and hemoglobin fluorescence provide strong evidence that heme is the fluorophore in hemoglobin. Then we studied the fluorescence properties of hemin, globin and methemoglobin, and found that the hemin may have the main effect on the methemoglobin fluorescence and that globin has tryptophan fluorescence like other proteins. Finally, since heme is a centrosymmetric molecule, that the Soret band fluorescence of heme and hemoglobin was not observed in the single photon process in the previous study may be due to the parity selection rule. The discovery of heme two-photon excited fluorescence may open a new window for heme biology research, since heme as a cofactor of hemoprotein has many functions, including chemical catalysis, electron transfer and diatomic gases transportation

RLSchert: An HPC Job Scheduler Using Deep Reinforcement Learning and Remaining Time Prediction

The job scheduler plays a vital role in high-performance computing platforms. It determines the execution order of the jobs and the allocation of resources, which in turn affect the resource utilization of the entire system. As the scale and complexity of HPC continue to grow, job scheduling is becoming increasingly important and difficult. Existing studies relied on user-specified or regression techniques to give fixed runtime prediction values and used the values in static heuristic scheduling algorithms. However, these approaches require very accurate runtime predictions to produce better results, and fixed heuristic scheduling strategies cannot adapt to changes in the workload. In this work, we propose RLSchert, a job scheduler based on deep reinforcement learning and remaining runtime prediction. Firstly, RLSchert estimates the state of the system by using a dynamic job remaining runtime predictor, thereby providing an accurate spatiotemporal view of the cluster status. Secondly, RLSchert learns the optimal policy to select or kill jobs according to the status through imitation learning and the proximal policy optimization algorithm. Extensive experiments on real-world job logs at the USTC Supercomputing Center showed that RLSchert is superior to static heuristic policies and outperforms the learning-based scheduler DeepRM. In addition, the dynamic predictor gives a more accurate remaining runtime prediction result, which is essential for most learning-based schedulers

Nonlinear optical microscopy for in vivo imaging microvasculature and blood flow

We demonstrate in vivo microvasculature and blood flow imaging based on two-photon excited autofluorescence of blood plasma and NADH in zebrafish. The blood flow images enable counting circulating leukocyte for detecting acute sterile inflammation. © 2014 OS

Two-photon excited endogenous fluorescence for label-free in vivo imaging ingestion of disease-causing bacteria by human leukocytes

Real time and in vivo monitoring leukocyte behavior provides unique information to understand the physiological and pathological process of infection. In this study, we demonstrate that two-photon excited reduced nicotinamide adenine dinucleotide (NADH) fluorescence provides imaging contrast to distinguish granulocyte and agranulocyte. By using spectral and time-resolved NADH fluorescence, we study the immune response of human neutrophils against bacterial infection (Escherichia coli). The two-photon excited NADH fluorescence images clearly review the morphological changes from resting neutrophils (round shape) to activated neutrophils (ruffle shape) during phagocytosis. The free-to-bound NADH ratio of neutrophils decreases after ingesting disease-causing pathogen: Escherichia coli. This finding may provide a new optical tool to investigate inflammatory processes by using NADH fluorescence in vivo

Label-free in vivo imaging of human leukocytes using two-photon excited endogenous fluorescence

We demonstrate that two-photon excited endogenous fluorescence enables label-free morphological and functional imaging of various human blood cells. Specifically, we achieved distinctive morphological contrast to visualize morphology of important leukocytes, such as polymorphonuclear structure of granulocyte and mononuclear feature of agranulocyte, through the employment of the reduced nicotinamide adenine dinucleotide (NADH) fluorescence signals. In addition, NADH fluorescence images clearly reveal the morphological transformation process of neutrophils during disease-causing bacterial infection. Our findings also show that time-resolved NADH fluorescence can be potentially used for functional imaging of the phagocytosis of pathogens by leukocytes (neutrophils) in vivo. In particular, we found that free-to-bound NADH ratios measured in infected neutrophils increased significantly, which is consistent with a previous study that the energy consumed in the phagocytosis of neutrophils is mainly generated through the glycolysis pathway that leads to the accumulation of free NADH. Future work will focus on further developing and applying label-free imaging technology to investigate leukocyte-related diseases and disorders. (C) 2013 Society of Photo-Optical Instrumentation Engineers (SPIE

Evaluation of Platelet Distribution Width as an Early Predictor of Acute Kidney Injury in Extensive Burn Patients

Background. The extensive burns devastate trauma. The research was designed to analyse the predictive value of early platelet (PLT) indices on the development of acute kidney injury (AKI) after severe burns. Methods and Results. 186 patients with extensive burns (burn area ≥30%) were eventually involved. Multivariate analyses pointed out that platelet distribution width (PDW) in the first 24 h after admission was an independent risk factor for AKI, severe AKI, and RRT requirement in patients with severe burns, and AKI risk showed an increase of 30.9% per increase of 1% in PDW (OR = 1.309, CI, 1.075–1.594, and P = 0.007). It was found that the area under the ROC curve (AUC) of PDW predicting AKI was 0.735 and that the AUC value was 0.81 for AKI after combining PDW and blood urea nitrogen (BUN). Based on the cut-off value PDW = 17.7%, patients were divided into high- (PDW ≥17.7%) and low-risk (PDW 17.7%, burn patients are not only at a higher risk for AKI but may also have higher AKI severity. Due to low cost and wide availability, PDW has the potential to be the tool that can predict AKI in extensive burn patients