Field Investigation of Face Spall in Moderate Strength Coal Seam at Vang Danh Coal Mine, Vietnam

Face spall in moderate strength coal seam occurs less frequently but can be more severe and takes a longer time to remedy compared to face spall in the weak coal seam. This paper presents a field investigation of face spall in moderate strength coal seam at Face I-8-1, Vang Danh coal mine, Quang Ninh coal field, Vietnam. The leg pressure of shield support and face condition were monitored within two months, and on-site remedial measures to the spall were discussed. The monitoring results confirmed that the front and rear leg pressure profiles are consistent with world-wide observations. The coal face condition in actual operation was found to be more stable than that in project design. The face spall occurred along face dip direction, but mostly in small extent of less than 0.5 m deep and during transitional time between working shifts. Proper ground control near gate ends by using higher capacity shield supports and supplemental hydraulic props was identified to improve face stability in the area. On-site remedial measures proved their efficiency in small to moderate face spall extent. For main roof rupture-associated face spall, technical measures have been applied but they need further investigation to clarify their effectiveness. The paper’s results can be consulted to improve longwall face stability control in similar coal seam conditions.

Equine Responses to Acceleration and Deceleration Cues May Reflect Their Exposure to Multiple Riders

It is logical to assume that horses with multiple riders encounter variation in application of training cues. When training cues are inconsistent, we expect to see a decrease in trained responses or an increase in conflict behaviours. This study investigated the relationship between the number of people that regularly ride or handle a horse and the horse’s response to operant cues. Data on 1819 equids were obtained from the Equine Behavior Assessment and Research Questionnaire (E-BARQ), an online global survey of horse owners and caregivers. Three mutually independent indices (acceleration, deceleration, and responsiveness) were derived from a parallel analysis of E-BARQ items related to acceleration and deceleration cues. These indices were then subjected to multivariable modelling against a range of dependent variables including horse and human demographics, horse management, and the number of riders or handlers. The number of riders or handlers was a significant predictor for two out of three indices. As the number of riders or handlers increased, horses were more difficult to accelerate (regression coefficient = 0.0148 ± 0.0071; p = 0.0366) and less difficult to decelerate (regression coefficient = −0.017 ± 0.008; p = 0.030) than those with fewer riders or handlers. These findings suggest that horses’ responses to rein tension cues are more persistent than their responses to leg pressure or whip cues. Alternatively, horses with these responses may be actively selected for multiple rider roles. Longitudinal studies of this sort should reveal how the number of riders or handlers affects horse behaviour and could lead to safer and more humane equestrian practices.

Mechanical Model of the Initial Leg Pressure Increment of the Shield and Its Application to Monitor Roof Load in Longwall Panels

The shield pressure cannot always be used to represent the upper load of longwall panels, since its value is steady or even decreases by the yielding action. However, the leg pressure increment of the shield (LPIS) at the initial stage is not influenced by yielding and could therefore be an important factor to judge the state of overlying loads. In this study, a mechanical model is established to analyze the relationship between the overlying loads of the main roof and LPIS after cutting. There is a linear positive correlation between leg pressure increment and overlying loads and a second-order relationship between leg pressure increment and length of main roof cantilever in the proposed model. Therefore, it can be used to determine the magnitude of roof weighting strength in different periods as well as the length of the main roof cantilever in a period. Finally, the mine pressure difference between the period of fully mechanized mining and the period of fully mechanized caving mining in the MinDong-1 coal mine serves to verify the rationality of the proposed model.

Feasibility study to evaluate cycloidal vibration therapy for the symptomatic treatment of intermittent claudication

Introduction Intermittent claudication (IC) is the most common symptom of peripheral arterial disease. Previous research has suggested that cycloidal vibration therapy (CVT) may induce angiogenesis and improvements in circulation. The objective of this feasibility study was to explore trial design and acceptability of the protocol to provide data to estimate the parameters required to design a definitive randomised control trial. This feasibility study specifically aimed to assess recruitment rate; attendance rates at baseline and follow-up; and safety, tolerability, and compliance with therapy device and additionally, to consider the potential efficacy of CVT as a novel treatment for intermittent claudication. Methods Patients with intermittent claudication (IC) were recruited and CVT was applied at home for 30 min twice a day for a period of 12 weeks. Primary outcomes were pain-free walking time (PFWT) and maximum walking time (MWT) after 12 weeks of treatment. Secondary outcomes included the ankle-brachial index and ankle systolic blood pressure. Participants were assessed during active therapy phase at baseline, week 4, week 8, and week 12. Results Thirty-four participants with IC were recruited: 30 (88%) male and 4 (12%) female. The rate of recruitment was 2.4 participants per month from a standard-size district general hospital. No participants left the study during the activity therapy stage, and no participant failed to attend their follow-up appointment. The general compliance with CVT was high. No participants dropped out during the treatment phase. The mean age of all participants was 68 years (IQR 60–75 years). Substantive improvements were seen in a comparison of differences in times to PFWT and MWT, in ABPI, and in systolic leg pressure in the treated leg. There was no evidence of a substantive difference from baseline in systolic leg pressure in the untreated leg. There were no immediate or delated treatment safety concerns of documented adverse effects with the treatment, all patients completed the required 12-week course indicated a high degree of patient acceptability. Conclusion The statistically significant and substantive improvements from baseline after 12 weeks observed in PFWT and MWT in participants experiencing IC are comparable to improvements seen from other treatment options such as supervised exercise as reported by Stewart et al. (N Engl J Med 347:1941–1951, 2002). The substantive improvement in systolic leg pressure in the treated leg and the concurrent absence of a substantive change in systolic leg pressure in the untreated leg over the same period suggests a causative effect. This study has provided novel information relating to the number of potential eligible participants for a further research trial and potential association between CVT and improved symptoms. Additionally, it has established that CVT treatment is highly acceptable, as indicated by no participant drop-out in the treatment phase, and may potentially offer an alternative treatment option for patients experiencing IC. Furthermore, this study has assessed the variability of the primary outcome measure which provides vital information needed to calculate sample sizes for any future studies. In conclusion, this study has established the feasibility of using CVT to improve patients’ symptoms of IC and provides essential information which will contribute to the design of future research investigating whether the improvements seen are directly related to CVT.

Shield-Roof Interaction in Longwall Panels: Insights from Field Data and Their Application to Ground Control

The shield-roof interaction as mining proceeds in longwall panels remains unclear, hindering the further increase of longwall productivity. To uncover the mechanisms of shield-roof interaction, using our self-developed Status of Shield and Roof IntelliSense (SSRI) system, we investigated the effects of idle time, retreating rate, setting pressure, yielding, and shearer’s cutting, as well as neighboring shields’ advance on the spatial-temporal evolution of leg pressure and leg closure of shields. Our results show that the shield-roof interaction is not only dependent on the shield capacity, but also collectively determined by the time-related factors, the geological condition, the setting pressure, yielding characteristics, and mining method. Understanding the shield-roof interaction in longwall panels enables us to apply the SSRI system for ground control in longwall coal mines. Early warning of severe roof weighting can be achieved by establishing a warning model based on the decision tree algorithm. Apart from this, we can also assess the working condition of yield valve and diagnose fluid leakage of shield cylinder using the SSRI system. Finally, we propose the research prospects on shield-roof interaction in longwall panels to achieve a more reasonable determination of shield capacity, prediction of roof fall and coal wall spalling, and self-adaptive control of the shield.

Osteochondroma-Related Pressure Erosions in Bony Rings Below the Waist

This article investigates the clinical and radiological features of four cases of osteochondroma-related bony pressure erosion in adults. Rare imaging features of extrinsic pressure erosions on adjacent bones caused by solitary and familial forms of osteochondroma are presented. Although described to occur uncommonly in the paired bones of the lower leg, pressure erosion in the pelvic girdle is poorly understood. In this article, we discuss clinical contexts for management of osteochondroma-related bony pressure erosion in the mature skeleton.

Sex differences in limb vasoconstriction responses to increases in transmural pressures

Women compared with men are more likely to have orthostatic intolerance. The purpose of this study was to examine whether sex affects limb vasoconstrictor response to increases in transmural pressure. Brachial and femoral mean blood velocity (MBV) and diameter (Doppler Ultrasound) were measured in 10 women and 10 men as transmural pressure was altered by applying local suction (−25, −50, −75, and −100 mmHg) via pressurized-limb tanks for 1 min to a single arm and leg. With the abrupt application of forearm suction (−75 and −100 mmHg), women compared with men had a greater initial rise in MBV (peak), followed by a quicker dynamic rate of velocity reduction. In the leg, women had a tendency for higher peak MBV but had similar dynamic velocity reductions compared with men. After 60 s of suction, women compared with men had attenuated reductions in brachial flow and conductance (−8.05 ± 1.71 vs. −16.25 ± 1.71 ml/min; −0.12 ± 0.03 vs. −0.20 ± 0.03 ml·min−1·mmHg−1; main effect, P < 0.05), as well as attenuated femoral flow and conductance to sustained leg negative pressure at −100 mmHg ( P < 0.05). When the data were expressed as percent change, women compared with men continued to have attenuated brachial flow responses (−24 ± 2 vs. −36 ± 2%, main effect, P < 0.05), with a trend toward attenuation at the highest leg pressure (−25 ± 11 vs. −46 ± 4%; P = 0.08). These sex differences remained after normalizing the flow responses by limb volume (percent change). Our findings suggest that young women compared with men have attenuated brachial and femoral vasoconstrictor responses to increases in transmural pressure, which may have implications for the greater incidence of orthostatic intolerance in women.