A new criterion of coal burst proneness based on the residual elastic energy index

To evaluate the coal burst proneness more precisely,a new energy criterion namely the residual elastic energy index was proposed.This study begins by performing the single-cyclic loading-unloading uniaxial compression tests with five pre-peak unloading stress levels to explore the energy storage characteristics of coal.Five types of coals from different mines were tested,and the instantaneous destruction process of the coal specimens under compression loading was recorded using a high speed camera.The results showed a linear relationship between the elastic strain energy density and input energy density,which confirms the linear energy storage law of coal.Based on this linear energy storage law,the peak elastic strain energy density of each coal specimen was obtained precisely.Subsequently,a new energy criterion of coal burst proneness was established,which was called the residual elastic energy index(defined as the difference between the peak elastic strain energy density and post peak failure energy density).Considering the destruction process and actual failure characteristics of coal specimens,the accuracy of evaluating coal burst proneness based on the residual elastic energy index was examined.The results indicated that the residual elastic energy index enables reliable and precise evaluations of the coal burst proneness.

Residual urinary output in high body mass index individuals on chronic hemodialysis:A disregarded life vest?

AIM： To assess residual diuresis and diverse variables according to body mass index （BMI）.METHODS： Cross-sectional study （n = 57）, with 3 groups. Group A： BMI 〈 25, n = 22; Group B： BMI 25-30, n = 15; Group C： BMI 〉 30, n = 20. Diuresis, hematocrit, albumin, C-reactive protein, Malnutrition infammatory score, Pro-BNP, Troponin T, leptin and in-sulin levels are expressed as median and ranges （r）. RESULTS： Albumin （g/dL）： GA vs GC, 3.70 （r2.20-4.90） vs 3.85 （r3.40-4.90）, P = 0.02. Diuresis （mL/d）： GA 690 （r0-1780）; GB 660 （r60-1800）; GC 840 （r40-2840）. Diuresis GA vs GC, P = 0.01. Leptin （ng/mL）： GA vs GC, 3.81 （r0.78-69.60） vs GC, 32.80 （r0.78-124.50）, P 〈 0.001. Insulin （μU/mL）： GA vs GB, 7 （r2-44） vs 11.50 （r4-38）, P = 0.02; GA vs GC, 7 （r2-44） vs 19.5 （r5-155）, P = 0.0001. Troponin T and Pro-BNP levels were not different. Significant correlations： GC, Insulin-UF： ρ= 0.53; P = 0.03; TroponinT-diuresis： ρ = -0.48, P 〈 0.05; Pro-BNP-diuresis： ρ = -0.39, P 〈 0.01; Troponin T-ProBNP： ρ = 0.77, P 〈 0.0001; albumin-Troponin T： ρ = -0.66, P 〈 0.0001; albumin-ProBNP： ρ = -0.44, P 〈 0.05.CONCLUSION： High BMI associated positively with higher diuresis and albuminemia, and negatively with TropT and Pro-BNP. High BMI-associated better survival may be explained by better urinary output, lowering cardiovascular stress.

A comparative analysis of Japanese firm productivity： Solow residual and Malmquist productivity index

For some time, two major kinds of Total Factor Productivity （TFP） have existed independently of each other： the Solow residual and the Malmquist Productivity Index （MPI）. The Solow residual was introduced in macro economic growth models, and the MPI has been used in micro economics and management studies. As both indices were developed independently, few studies utilize both together and compare the results. This paper uses the same data to compare the two productivity indices by setting to determine the economic implications of combining the two indices. We discovered that we could decompose TFP with each aspect of the Soiow residual and MPI. We could then interpret their relationship in the business cycle. Our results indicated that the frontier shift in MPI of Japanese firms often occurred when the Solow residual increased, meaning that improving oroductivitv with the Solow residual could be generated by a firm that could shift new production frontiers.

Prediction of the residual strength of clay using functional networks

Landslides are common natural hazards occurring in most parts of the world and have considerable adverse economic effects. Residual shear strength of clay is one of the most important factors in the determination of stability of slopes or landslides. This effect is more pronounced in sensitive clays which show large changes in shear strength from peak to residual states. This study analyses the prediction of the residual strength of clay based on a new prediction model, functional networks（FN） using data available in the literature. The performance of FN was compared with support vector machine（SVM） and artificial neural network（ANN） based on statistical parameters like correlation coefficient（R）, Nash–Sutcliff coefficient of efficiency（E）, absolute average error（AAE）, maximum average error（MAE） and root mean square error（RMSE）. Based on R and E parameters, FN is found to be a better prediction tool than ANN for the given data. However, the R and E values for FN are less than SVM. A prediction equation is presented that can be used by practicing geotechnical engineers. A sensitivity analysis is carried out to ascertain the importance of various inputs in the prediction of the output.

Impact of disease severity on gastric residual volume in critical patients

AIM: To investigate whether illness severity has an impact on gastric residual volume (GRV) in medical critically ill patients. METHODS: Medical intensive care unit (ICU) patients requiring nasogastric feeding were enrolled. Sequential Organ Failure Assessment (SOFA) score was assessed immediately preceding the start of the study. Acute Physiology and Chronic Health Evaluation (APACHE) Ⅱ scores were recorded on the first, fourth, seventh, and fourteenth day of the study period. GRV was measured every 4 h during enteral feeding. The relationship be-tween mean daily GRV and SOFA scores and the correlation between mean daily GRV and mean APACHE Ⅱ score of all patients were evaluated and compared. RESULTS: Of the 61 patients, 43 patients were survivors and 18 patients were non-survivors. The mean daily GRV increased as SOFA scores increased (P < 0.001, analysis of variance). Mean APACHE Ⅱ scores of all patients correlated with mean daily GRV (P = 0.011, Pearson correlation) during the study period. Patients with decreasing GRV in the first 2 d had better survival than patients without decreasing GRV (P = 0.017, log rank test). CONCLUSION: GRV is higher in more severely ill medical ICU patients. Patients with decreasing GRV had lower ICU mortality than patients without decreasing GRV.

Accuracy design of ultra-low residual reflection coatings for laser optics

Refractive index inhomogeneity is one of the important characteristics of optical coating material, which is one of the key factors to produce loss to the ultra-low residual reflection coatings except using the refractive index inhomogeneity to obtain gradient-index coating. In the normal structure of antireflection coatings for center wavelength at 532 nm, the physical thicknesses of layer H and layer L are 22.18 nm and 118.86 nm, respectively. The residual reflectance caused by refractive index inhomogeneity（the degree of inhomogeneous is between -0.2 and 0.2） is about 200 ppm, and the minimum reflectivity wavelength is between 528.2 nm and 535.2 nm. A new numerical method adding the refractive index inhomogeneity to the spectra calculation was proposed to design the laser antireflection coatings, which can achieve the design of antireflection coatings with ppm residual reflection by adjusting physical thickness of the couple layers. When the degree of refractive index inhomogeneity of the layer H and layer L is-0.08 and 0.05 respectively, the residual reflectance increase from zero to 0.0769% at 532 nm. According to the above accuracy numerical method, if layer H physical thickness increases by 1.30 nm and layer L decrease by 4.50 nm, residual reflectance of thin film will achieve to 2.06 ppm. When the degree of refractive index inhomogeneity of the layer H and layer L is 0.08 and -0.05 respectively, the residual reflectance increase from zero to 0.0784% at 532 nm. The residual reflectance of designed thin film can be reduced to 0.8 ppm by decreasing the layer H of 1.55 nm while increasing the layer L of 4.94 nm.

Residual Spray for the Control of <i>Aedes</i>Vectors in Dengue Outbreak Residential Areas

The incidence of dengue in Malaysia has shown an increasing trend since the year 2000. Vector control is the primary approach for dengue control in Malaysia. There is an urgent need for new or modified approaches such as the residual spraying on the outer walls that can potentially last long enough to control the Aedes population, particularly in the outbreak-prone areas. In this field study, we conducted outdoor residual spraying (ORS) using a newly formulated polymer-enhanced suspension concentrate (SC-PE) of deltamethrin. The objectives of this study were to evaluate the efficacy of ORS using deltamethrin SC-PE and its effect on wild Aedes populations and to assess its residual bio-efficacy on painted cement walls against the pyrethroid-susceptible strains of laboratory-reared Aedes mosquitoes. Three rounds of spraying in a four-month cycle were conducted between 2014 and 2015 in four residential areas (low-rise and high-rise housing types) in Hulu Langat, Selangor. The bio-efficacy of the insecticide was evaluated by assessing its impact on vector population using ovitrap surveillance. Standard WHO wall deposit bioassay was adapted to determine bio-efficacy of deltamethrin, i.e. post 30 min knockdown and post 24 h mortality after exposure. During the treatment period, we observed significant reductions in the population of Ae. albopictus in the sprayed low-rise housing in both semi-indoor and outdoor environments, while in the high-rise housing, there was also a significant decline in Ae. aegypti population in the semi-indoor environment. The evaluation of the residual bio-efficacy of deltamethrin SC-PE against laboratory-reared Aedes mosquitoes showed that the insecticide lasted longer in the high-rise housing compared to the low-rise housing with >80% mortality achieved continuously for 16 weeks. We provide initial evidence on residual efficacy of deltamethrin SC-PE in reducing Aedes population size in the low-rise and high-rise housing. Our results showed that ORS is a promising tool in the dengue vector control and like IRS in malaria control;it is a powerful and effective method if conducted correctly. However, large scale and well-designed studies with entomological and epidemiological endpoints are still warranted before its routine use in dengue control.

Influence of Polyaluminum Chloride Residue on the Strength andMicrostructure of Cement-Based Materials

In this paper,cement and dechlorinated Polyaluminum Chloride Residue(PACR)have been used to prepare a net slurry and mortar specimens.Two hydration activity indicators have been used to quantitatively analyze the dechlorinated PACR hydration activity.In particular,the effect of dechlorinated PACR content on the compressive strength of mortar has been assessed by means of compressive strength tests.Moreover,X-ray diffraction(XRD)and scanning electron microscopy(SEM)have been employed to observe the microstructure of the considered hydration products.The following results have been obtained.The 28th day activity index of the dechlorinated PACR is 75%,and therefore it meets the criterion for the use of active admixture.The increase in the content of the dechlorinated PACR tends to reduce the compressive strength of mortar specimens,however,it is beneficial to its later strength growth.When the content is not greater than 10%,the strength remains unchanged,otherwise,it decreases.The PACR does not form a new crystalline phase in the cement slurry,and the dechlorinated PACR remains active until the age of the 28th day.The inclusion of the PACR mainly deteriorates the early strength of the cement slurry,but it promotes the production of hydration products in the cement slurry after the 7th day.

Environmental availability and ecological risk assessment of heavy metals in zinc leaching residue

Four different methods,namely mineralogical analysis,three-stage BCR sequential extraction procedure,dynamic leaching test and Hakanson Potential Ecological Risk Index Method were used to access the environmental activity and potential ecological risks of heavy metals in zinc leaching residue.The results demonstrate that the environmental activity of heavy metals declines in the following order：CdZnCuAsPb.Potential ecological risk indices for single heavy metal are CdZnCuAsPb.Cd has serious potential ecological risk to the ecological environment and contributes most to the potential toxicity response indices for various heavy metals in the residue.

Production of New Adsorbent from Mango residues Collected in the Urban Community of Mamou

Activated coal obtained from mango residues is an alternative for the valorisation of these wastes for applications. This work focuses on the production of a new adsorbent from mango residues collected in the urban common of Mamou (Republic of Guinea) by chemical activation with potassium hydroxide. To do this, the different rates: humidity, cinders, volatile matter, fixed carbon et iodine indices before activation and after activation at 400&deg;C and 700&deg;C were determined which are: (6.28%;0.97%;73.80%;25.23%) respectively. The best indices were found in powdered activated coal compared to grain activated coal for the concentrations used. This study can be an alternative bio-adsorbent for the urban community of Mamou in water treatment.

Investigation and Evaluation on Heavy Metal Content and Pesticide Residues of Three Edible Forest Products in Central Sichuan Province

Taking three mains edibles products(walnut, prickly ash and bamboo shoots) and origin soil in central area of Sichuan Province as the study objects, this research aimed at revealing the level of heavy metals and pesticide residue and comprehensive evaluation the soil heavy metal pollution in the region. The results showed that: ① Soil organic matter, total nitrogen, total phosphorus and heavy metal contents of mercury, arsenic in the south area were significant higher than that in the north area, while the heavy metal contents of lead and copper were significantly higher in the north area; ② The pollution index of six heavy metals of cadmium, mercury, arsenic, lead, chromium and copper in the producing area was less than 1.0. However, the integrated pollution index was at a warning level, and there was a potential risk of cadmium contamination; ③ The walnut samples exceeded the lead limit value over 75% in the north area and over 35% in the south area, and the same as 30% of bamboo shoot samples; ④ There was a significant negative correlation of mercury content between walnut samples and production soil, and a significant positive correlation of arsenic content between bamboo shoots and production soil. In addition, there is no significant correlation of heavy metal contents between prickly samples and production soil; ⑤ Fenthion residues were detected in walnuts, malathion samples were detected in prickly ash, and chlorothalonil, dimethoate and chlorpyrifos residues in bamboo shoots samples. None of theses pesticide residues exceeded the standard limit value. In general, the soil is in well sanitary condition and the edible forest products are not exposed to the contamination of pesticide residues in the study area. The quality and safety of the prickly ash is good while the walnut and bamboo shoots have certain risks in terms of high lead level.

GC/LC-Q/TOF MS测定当归中农药残留及膳食风险评估

采用气相色谱/液相色谱-四极杆飞行时间质谱(GC/LC-Q/TOF MS)对100例市售当归样品进行了989种农药残留分析,按照风险排序法对检出农药的风险等级进行归类,采用点评估法评估了检出农药的慢性、急性膳食摄入风险,危害指数法(HI)计算了累积风险值。100例当归的总检出率为95%,共检出27种农药,其中甲拌磷和毒死蜱的检出率较高,农药残留量为0.0010~1.4077 mg/kg。依据《中国药典(2020年版)》和GB 2763-2021,检出农药中只有甲拌磷、甲基异柳磷、特丁硫磷有最大残留限量(MRL)值,其中甲拌磷的超标率最高。风险排序结果表明,高风险农药为甲拌磷、特丁硫磷、甲基异柳磷。膳食摄入风险和累积风险结果显示,检出农药的慢性膳食摄入风险(%ADI)和急性膳食摄入风险(%ARfD)平均值分别为0.2908%和0.0978%,均远低于100%;慢性累积暴露危害指数(HIc)和急性累积暴露危害指数(HIa)分别为0.06689和0.01173,均远小于1,慢性和急性膳食摄入风险及累积风险均处于可接受水平。当归中检出农药的膳食摄入和累积暴露的风险均较低,但仍需加强对农药使用的监管,建议制定当归中检出的中等风险农药的MRL值。

基于机器学习的CFST柱高温剩余强度系数预测方法

目的 为提高计算精度和速度,利用机器学习模型泛化数据,以预测CFST柱的高温剩余强度系数。方法 利用生成对抗网络将搜集到的110个试验结果泛化生成407组数据,据此训练机器学习模型,并使用试验结果评估其性能,以确定最优模型;然后使用生成数据输入建立的模型预测CFST柱高温剩余强度系数,并和现有计算方法进行对比。结果 建立的随机森林模型在性能度量上表现最好,拟合优度达到0.947 7,均方误差为0.001 8,精度为94.7%;预测结果误差在±10%内的数据为83%,在±20%内的数据为100%;剩余强度系数主要影响因素依次为温度、钢材屈服强度、混凝土抗压强度和横截面积,钢管厚度影响很小。结论 提出的预测方法优于现有计算方法,具有更快的计算速度、更小的结果误差以及更强的模型可解释性,该方法可为CFST柱抗火设计提供参考。

煤岩组合体冲击倾向性对超低摩擦型冲击地压的影响机制

为揭示煤岩组合体冲击倾向性程度对超低摩擦型冲击地压的影响机制,以不同冲击倾向性煤岩组合体为研究对象,在对煤岩组合试件进行冲击倾向性测定的基础上,采用自行研制的煤岩界面超低摩擦试验装置,以发生超低摩擦效应时的水平位移、动能、摩擦力为指标,探究煤岩组合体冲击倾向性与垂直应力波扰动频率、扰动振幅之间的关系特征。研究结果表明:(1)受扰动频率影响,弱、强冲击倾向煤岩组合体易发生超低摩擦效应的频率显著影响区分别为2.0~3.0,2.5~3.5 Hz,且随着冲击倾向性程度的增强,频率显著影响区逐渐右移。(2)相比于弱冲击倾向性煤岩组合体,强冲击倾向性煤岩组合体发生超低摩擦效应时水平位移、动能和摩擦力降幅较大,煤块易发生超低摩擦滑动。(3)随着煤岩组合体剩余能量指数的增大,冲击倾向性程度逐渐增强,动能呈指数规律增大,煤块越易发生超低摩擦滑动。研究结果可为超低摩擦型冲击地压的预测和防治提供参考。

发酵木薯渣对湖羊生长性能、血清生化指标及经济效益的影响

试验旨在探究在饲料中添加不同含量的发酵木薯渣对湖羊生长性能、血清生化指标及经济效益的影响。选择断奶湖羊48只,随机分成4组,每组12个重复,每个重复1只羊。各组湖羊分别饲喂添加0(对照组)、10%、20%和30%发酵木薯渣的饲粮。预试期7 d,正式试验期60 d。结果显示:与对照组相比,20%发酵木薯渣组湖羊的末重、总增重、平均日增重显著增加(P<0.05),料重比显著降低(P<0.05);血清中总蛋白、白蛋白含量显著升高(P<0.05),尿素氮含量显著降低(P<0.05);10%、20%发酵木薯渣组谷草转氨酶活性显著降低(P<0.05);10%、30%发酵木薯渣组肌酐含量显著升高(P<0.05);20%、30%发酵木薯渣组尿酸含量显著升高(P<0.05)。与对照组相比,各发酵木薯渣组湖羊的增重收入分别增加了10.68%、23.76%、16.57%,养殖利润分别增加了10.36%、36.92%、14.99%。研究表明,饲粮中添加20%的发酵木薯渣可以改善湖羊的生产性能,养殖经济效益较好。

矿井水酸碱度对遗煤氧化的影响及微观作用特性

为研究矿井水酸碱度(pH值)对采空区遗煤自燃特性的影响,采用平顶山煤矿的长焰煤,通过C600高精度微量热仪和气相色谱仪联用,分析低温氧化阶段衍生气体产气规律和热流曲线,并基于实验结果讨论其中的微观机理。研究结果表明:酸性水溶液浸泡显著促进了煤的氧化性能,且酸性越强,影响越大;碱性水溶液浸泡抑制了煤样的氧化性能;根据推断,认为可能是酸性溶液与煤中的矿物质反应,造成煤的孔隙率增大,促进了煤自燃反应的进程;而碱性溶液与煤样反应产生了沉积物,在一定程度上抑制了煤自燃反应。

百令胶囊治疗早期腹膜透析患者的疗效分析

目的:研究百令胶囊治疗早期腹膜透析(EPD)患者的疗效。方法:选取2019年1月—2020年12月就诊于宜昌市中心人民医院的100例EPD患者,采用随机数字表法将其分成两组,对照组患者接受EPD治疗(n=50),观察组患者行EPD治疗的同时加服百令胶囊(n=50)。对比研究两组患者治疗三个月后的肾功能、营养状况、微炎症因子及氧化应激指标。结果:在改善肾功能方面,观察组患者残余肾功能(RRF)、24 h尿量及24 h超滤量均显著高于对照组(均P<0.05);在营养状态方面,观察组患者血清白蛋白(Alb)、前白蛋白(PA)、转铁蛋白(TRF)及血红蛋白(Hb)明显高于对照组(均P<0.05),且观察组患者的改进主观全面营养评定量表(MQSGA)明显降低(10.02±1.05分vs 12.54±2.20分,P<0.05);在微炎症指标方面,观察组血清白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、超敏C反应蛋白(hs-CRP)、血管内皮生长因子(VEGF)、转化生长因子-β1(TGF-β1)水平均明显低于对照组(均P<0.05);在氧化应激方面,观察组患者血清中丙二醛(MDA)、同型半胱氨酸(Hcy)含量较对照组均显著降低,超氧化物歧化酶(SOD)活力明显高于对照组(均P<0.05);两组患者不良反应无明显差异(P>0.05)。结论:百令胶囊可有效缓解EPD患者氧化应激反应、减轻微炎症状态,改善营养不良,提高患者的肾功能。

基于Sentinel-2遥感影像的玉米秸秆覆盖度估算研究

作物秸秆作为农业生产活动中的重要物质,在减少土壤侵蚀、提高土壤保熵及增加土壤团聚体等方面发挥着重要的作用,因此通过遥感技术对大范围作物秸秆覆盖度进行监测具有重要的意义。本研究以样线法和图像分割法2种方法对玉米秸秆覆盖度(Crop Residue Cover,CRC)进行野外采样测量,以Sentinel-2影像为基础,利用遥感光谱指数和纹理特征作为特征变量,选择偏最小二乘法(Partial Least Squares Regression,PLSR)建立大范围CRC估算模型。结果表明:1)从遥感影像上提取的遥感光谱指数和纹理特征均与CRC有较好的相关性,其中,简单耕作指数(Simple Tillage Index,STI)与CRC相关性优于其他遥感光谱指数,样线法和图像分割法的决定系数(Coefficient of Determination,R^(2))分别为0.844和0.848;纹理特征与CRC的相关程度低于遥感光谱指数,其中B8A Mean纹理特征与玉米CRC相关性优于其他纹理特征,样线法和图像分割法的R 2分别为0.505和0.507。2)以遥感光谱指数为主、纹理特征为辅的组合方法构建的PLSR模型用于玉米CRC估算精度高于采用单一遥感光谱指数或纹理特征建模的CRC估算精度;其中样线法建模结果相关系数R 2达到0.896,图像分割法构建的模型相关系数R 2为0.892,因此,利用分辨率较高的Sentinel-2影像构建的遥感光谱指数和纹理特征建立PLUS模型在CRC估算方面精度较好,具有良好的应用前景。

2023年佛山市禅城区果蔬中腐霉利残留及膳食风险评估

目的:调查掌握佛山市禅城区市售不同种类果蔬的腐霉利残留情况,及时发现食品安全隐患,进行风险预警,为开展食品安全风险评估、食品安全标准制(修)订和采取针对性控制措施提供科学依据。方法:在佛山市禅城区4个镇街道不同销售流通环节随机采集6种果蔬样品共200份,使用QuEChERS法进行净化处理,参照GB 23200.113-2018采用气相色谱质谱联用法测定腐霉利的含量,根据检测结果运用急性和慢性膳食风险评价法以及食品安全指数法对其残留情况和由其引发的居民健康风险进行评价。结果:采集的样品中,43份样品检出腐霉利,检出率为21.50%,不同类型样品中腐霉利检出率差异具有统计学意义(χ^(2)=46.735,P<0.01);不同流通环节样品中的腐霉利检出率差异不具有统计学意义(χ^(2)=3.251,P=0.196>0.05);4个镇街道采集到的蔬菜水果腐霉利检出数总体上无显著性差异(χ^(2)=7.436,P=0.063>0.05);经急性和慢性膳食风险评价,受检产品的%ARfD和%ADI值均小于100%,表示摄入风险可接受;食品安全指数法评价本次受检农产品的结果为质量安全风险处在可接受范围。结论:佛山市禅城区果蔬农产品尚未发现腐霉利超标情况,食品安全风险可控,但有关部门需持续开展动态监控。

农药最大残留限量标准差异对我国茶叶出口RCEP成员国的贸易效率影响研究——基于随机前沿引力模型

目前,茶叶外贸面临着来自技术性贸易壁垒的挑战,以农药最大残留限量(MRLs)标准差异为切入点,构建异质性贸易指数(HIT)量化各国农药MRLs的具体差异,利用随机前沿引力模型研究农药MRLs标准差异对我国茶叶出口区域全面经济伙伴关系协定(RCEP)国家的贸易效率的影响。结果表明,中国与RCEP成员国的农药MRLs标准存在差异,但总体呈缩小的趋势。中国与RCEP成员国的农药MRLs标准的负面差异会导致中国出口茶叶的贸易效率降低;抑制作用路径表现为显著降低了茶叶出口额和出口单价。我国应进一步完善农药MRLs标准体系,使之与国际标准接轨,推动RCEP区域内国家间的标准互认,减小贸易壁垒的不利影响。