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Spontaneous heating in the active goaf area during normal mining processes poses increased threats to mine productivity and safety, as evidenced in events induced by spontaneous combustion of coal. To control and mitigate this engineering problem, there is a need to gain critical knowledge of spontaneous combustion in the longwall goaf area, which can be achieved through a combination of field tests and numerical modeling. This paper introduces the spontaneous combustion management system widely used in Australia and presents Computational Fluid Dynamics (CFD) models for the simulation of gas flow dynamics in the goaf area, based on the site conditions of an underground coal mine where coal seam gas is predominantly comprised of carbon dioxide. The models were validated with gas monitoring data and used to conduct parametric studies for proactive goaf inertisation optimization. Qualitative and quantitative analysis of simulation results indicated that better goaf inertisation could be achieved when nitrogen was injected via cut-through at 250 m on the maingate (MG) side and surface boreholes at 100 m and 700 m on the tailgate (TG) side, with a total injection rate greater than 1750 1/s. The oxygen concentration on the MG and TG side dropped below 5% at distances of 120 m and 75 m behind the longwall face, with an oxidation zone area of 35375 m2, which was approximately one-third of the oxidation zone area of the scenario without inert gas injection. Simulation results help shed light on improving current goaf inertisation practices to effectively reduce the risk of heating in goaf areas and improve mining process safety based on Australian conditions and practices. [ABSTRACT FROM AUTHOR]

Generalized anxiety disorder (GAD) is a significant and common mental illness with a lifetime prevalence of 3.7%. Regardless of the complexity of treatment decisions for GAD, few studies have conducted systematic comparisons of the efficacies of varying interventions. Thus, this study performed a valid network meta-analysis (NMA) of randomized controlled trials (RCTs) to synthesize direct and indirect evidence for alternative interventions for GAD. We searched four major bibliographic databases, the Cochrane Central Register of Controlled Trials, Embase, PsycINFO, and PubMed, for published RCTs of adult patients with a diagnosis of GAD and allowed for all comorbidities. A total of 91 articles (14,812 participants) were identified in the final NMA. The results showed that all pharmacological treatments except for serotonin modulators and second-generation antipsychotics had greater effects than placebo: norepinephrine–dopamine reuptake inhibitors (standardized mean difference (SMD) −1.84, 95% credible interval −3.05 to −0.62), noradrenergic and specific serotonergic antidepressants (−0.91, −1.62 to −0.20), melatonergic receptor agonists (−0.68, −1.15 to −0.21), selective serotonin reuptake inhibitors (SSRIs; −0.67, −0.90 to −0.43), azapirones (−0.58, −1.00 to −0.17), anticonvulsants (−0.56, −0.85 to −0.28), serotonin–norepinephrine reuptake inhibitors (SNRIs; −0.54, −0.79 to −0.30), and benzodiazepines (BZDs; −0.40, −0.65 to −0.15). Most psychological and self-help interventions exerted greater effects than the waitlist group. However, no psychological interventions had greater effects compared with the psychological placebo. Overall, most pharmacological interventions had larger effect sizes than psychological interventions, and most psychological interventions showed larger effect sizes than self-help interventions. [ABSTRACT FROM AUTHOR]

In this study, P- and S-wave velocity models were built based on two pre-stack depth migration (PSDM) profiles of long-offset reflection data and 25 four-component ocean-bottom seismometers (OBS) data at Jiulong Methane Reef off SW Taiwan in the passive margin of the northern South China Sea (SCS). According to the velocity models, the average P-wave velocity and Vp/Vs ratio of the free gas beneath the bottom-simulating reflector (BSR) are 1.52–1.58 km/s and 4.5–5.10, respectively. The depth of the BSR is found at 80–300 m below the sea floor and the sedimentary thickness of the hydrate and the free gas are about 50–100 m and 70–100 m, respectively. P-wave velocity of about 1.75 km/s in the hydrate-bearing sediment is southeastward increased to about 1.85 km/s above the BSR. Similarly, Vp/Vs ratio of about 3.06 in the hydrate-bearing sediment is increased southeastward to about 3.48 above the BSR. Based on the pseudo-3D map of gas-hydrate saturation estimated from the PSDM and OBS models, the average saturations of hydrate and free gas at Jiulong Methane Reef are about 7% and 0.9–2.4%, respectively. The highest hydrate saturation (11%) is located at 5–20 m above the BSR in the SE portion of the Jiulong Methane Reef. On the other hand, the highest gas saturation of about 2% is observed at 10–70 m below the BSR in the NW portion of the Jiulong Methane Reef. We suggested that several normal faults dipping southeastward beneath the continental slope provided conduits for gas migrating northwestward at Jiulong Methane Reef. Therefore, the highest gas saturation is observed below the anticline in the NW portion of the Jiulong Methane Reef and the highest hydrate saturation (high P-wave velocity and high Vp/Vs ratio) is identified above the BSR in the SE portion of the Jiulong Methane Reef. [ABSTRACT FROM AUTHOR]

Abstract: The reliability is a key factor for the design and manufacture of large vibrating screen. In the paper, we presented a new large vibrating screen with hyperstatic net-beam structure. Dynamic characteristic of the vibrating screen was researched and dynamic simulation method of large screening machines was explored. We used finite element method (FEM) to analyze dynamic characteristic of large vibrating screen with hyperstatic net-beam structure. Multi natural frequency, natural modes of vibration and dynamic response of the vibrating screen were calculated. The structural size of stiffeners on the side plate was optimized under multiple frequencies constraints and an adaptive optimization criterion was given. The results show that the vibrating screen’s structural strength is increased and the natural frequency of bending deformation is enhanced. The modal frequencies are far from working frequency, and thus the structure is able to avoid resonance effectively and reduce the destructiveness. The maximum transverse displacement of the vibrating screen is 0.13 mm, the maximum difference in vibration amplitude of corresponding points is 0.44mm and the maximum dynamic stress is 16.63MPa. The structural optimization shows that the mass of the side plate is decreased by 194.50kg, the second and third modal frequency is increased by 1.73% and 2.91% respectively and a better optimal effect is received. [Copyright &y& Elsevier]

As coal resources become exhausted in shallow mines, mining operations will inevitably progress from shallow depth to deep and gassy seams due to increased demands for more coal products. However, during the extraction process of deeper and gassier coal seams, new challenges to current gas control methods have emerged, these include the conflict between the coal mine safety and the economic benefits, the difficulties in reservoirs improvement, as well as the imbalance between pre-gas drainage, roadway development and coal mining. To solve these problems, a sequential approach is introduced in this paper. Three fundamental principles are proposed: the mining-induced stress relief effect of the first-mined coalbed should be sufficient to improve the permeability of the others; the coal resource of the first-mined seams must be abundant to guarantee the economic benefits; the arrangement of the vertical wells must fit the underground mining panel. Tunlan coal mine is taken as a typical example to demonstrate the effectiveness of this approach. The approach of integrating surface coalbed methane (CBM) exploitation with underground gas control technologies brings three major benefits: the improvement of underground coal mining safety, the implementation of CBM extraction, and the reduction of greenhouse gas emissions. This practice could be used as a valuable example for other coal mines having similar geological conditions. [ABSTRACT FROM AUTHOR]

Abstract: Power harmonic estimation is essential for evolving suitable protection and control strategies of power networks. Parametric approaches exhibit super-resolution and have been gradually applied in practice. However, they are susceptible to the presence of noise in the signals. The analysis accuracy will be abruptly reduced and even ineffective under non-Gaussian or impulsive noise environment. In this paper, a novel approach based on M-Estimators for harmonic estimation is proposed to overcome the above shortcomings. The derivation of Gauss–Newton iteration equations of harmonic frequency, amplitude and phase is presented. Further, the ESPRIT algorithm is also employed to acquire the initial values of harmonic frequencies, which avoids the objective function of M-Estimator to be stuck in local minima and improves the convergence rate of optimization. The numerical simulations and experimental results verify the feasibility and effectiveness of the proposed method. [Copyright &y& Elsevier]

Abstract: Inspired by polyhydroxylated pyrrolidine alkaloid natural products, a 18-membered library of 2-aryl polyhydroxylated pyrrolidines has been efficiently prepared in two or three synthetic steps from the known chiral cyclic nitrones with high yield and purity and excellent stereoselectivity. The inhibitory activity of all these compounds against various glycosidase enzymes was evaluated. Interestingly, 15 and 19 show better inhibitory activities than radicamine A (20) and B (18) against α-glucosidases. The IC50 values of 15 and 19 are 1.1 and 0.5μM, respectively. In this study, we also discovered the substituent(s) on the aryl ring could affect the inhibition potency and selectivity against glycosidases. [Copyright &y& Elsevier]

• Two IMPDH inhibitors and a DHODH inhibitor showed antiviral activity against FMDV in vitro. • The antiviral effect of AVN-944, mycophenolate mofetil and teriflunomide occurred in the early phases of FMDV replication. • The antiviral effect of teriflunomide could be attenuated by uridine supplementation. • Exogenous guanosine could abolish the antiviral activity of AVN-944 and mycophenolate mofetil. • In vivo activity of AVN-944 and teriflunomide were confirmed in a mouse model of infection. Foot-and-mouth disease virus (FMDV) is an important pathogen that affects livestock breeding and causes huge economic losses worldwide. Currently, the development of antiviral agents to combat FMDV infection at the early stages is being explored. As viral replication critically depends on the host for nucleoside supply, host enzymes involved in nucleotides biosynthesis may represent potential targets for the development of antiviral agents. In the present study, the effects of IMP dehydrogenase (AV N-9 44 and mycophenolate mofetil) and dihydroorotate dehydrogenase (teriflunomide) inhibitors were evaluated both in vitro and in vivo. The results revealed that these compounds were effective in suppressing FMDV (O/MY98/BY/2010 and A/GD/MM/2013) infection. With regard to the antiviral mechanism, time-of-addition experiments revealed that these compounds were effective when added at the early stages of viral lifecycle (0–8 h post infection). However, exogenous guanosine/uridine eliminated the antiviral activity of these compounds. Importantly, treatment AV N-9 44 and teriflunomide significantly improved the survival of mice that were subcutaneously treated with FMDV. Together, the results of the present study indicate the broad-spectrum activities of anti-FMDV agents targeting IMP dehydrogenase or dihydroorotate dehydrogenase, which could be useful in developing strategies to prevent FMD. [ABSTRACT FROM AUTHOR]