Correlations between direct and indirect strength test methods

The difficulties associated with performing direct compression strength tests on rocks lead to the development of indirect test methods for the rock strength assessment. Indirect test methods are simple, more economical, less time-consuming, and easily adaptable to the field. The main aim of this study was to derive correlations between direct and indirect test methods for basalt and rhyolite rock types from Carlin trend deposits in Nevada. In the destructive methods, point load index, block punch index, and splitting tensile strength tests are performed. In the non-destructive methods, Schmidt hammer and ultrasonic pulse velocity tests are performed. Correlations between the direct and indirect compression strength tests are developed using linear and nonlinear regression analysis methods. The results show that the splitting tensile strength has the best correlation with the uniaxial compression strength.Furthermore, the Poisson's ratio has no correlation with any of the direct and indirect test results.

INVERSE REGRESSION METHOD IN DATA STRUCTURE ANALYSIS

In order to explore the nonlinear structure hidden in high-dimensional data, some dimen-sion reduction techniques have been developed, such as the Projection Pursuit technique (PP).However, PP will involve enormous computational load. To overcome this, an inverse regressionmethod is proposed. In this paper, we discuss and develop this method. To seek the interestingprojective direction, the minimization of the residual sum of squares is used as a criterion, andspline functions are applied to approximate the general nonlinear transform function. The algo-rithm is simple, and saves the computational load. Under certain proper conditions, consistencyof the estimators of the interesting direction is shown.

Realization Path for Inclusive Finance to Support Rural Revitalization in Poverty-stricken Areas

Based on the quarterly economic,social and financial development data of 39 poverty-stricken counties in Henan Province during 2016-2018,this paper utilized the entropy-based TOPSIS method to objectively measure the rural revitalization index,and then built the quantile regression model to study the effects of various elements of inclusive finance on different stages of rural revitalization.Research results show that industrial development,agricultural modernization,targeted poverty alleviation,endogenous demand,and rural governance are the main points of inclusive finance in poverty-stricken areas to support rural revitalization;the rural revitalization index indicates that compared with the Dabie Mountain area and the non-contiguous poverty-stricken areas,the rural revitalization of the Qinba Mountain area is slower;for inclusive finance supporting rural revitalization,it is necessary to bring into play the role of monetary policy tools in re-lending,functions of credit in supporting industrial development,and role of insurance in risk protection;furthermore,inclusive finance solves problems such as the diminishing marginal effect of physical machinery investment in rural revitalization support,financial support for the coordinated development of small farmers and new agricultural business entities,financial support for the development of the entire industry chain,and the"siphon effect"of capital.

Optimization of vinegar-steaming process for Wuweizi (Fructus Schisandrae Chinensis) with response surface method

OBJECTIVE:To optimize the vinegar-steaming process of Wuweizi(Fructus Schisandrae Chinensis)using the response surface method(RSM)based on the Box-Behnken design.METHODS:A regression model was constructed with the response variables,the content of Deoxyschizandrin,and the three explanatory factors:length of steaming time,the quantity of vinegar and length of moistening time to evaluate the effects on the processing of Wuweizi(Fructus SchisandraeChinensis).RESULTS:There was a linear relationship between the content of Deoxyschizandrin and the three explanatory factors.When the steaming time was5.49 h,with 2.365 g of vinegar added and a moistening time of 4.13 h,the content of Deoxyschizandrin reached the maximum predicted value of0.1076%,and under the conditions the average content of Deoxyschizandrin was 0.1058%.CONCLUSION:The correlation coefficient of thenonlinear mathematical model was relatively high and the model matched the data well,potentially providing a method for the study of the steaming process.

Space-time clustering and associated risk factors of pulmonary tuberculosis in southwest China

Background:Pulmonary tuberculosis(PTB,both smear positive and smear negative)is an airborne infectious disease of major public health concern in China and other parts of the world where PTB endemicity is reported.This study aims at identifying PTB spatio-temporal clusters and associated risk factors in Zhaotong prefecture-level city,located in southwest China,where the PTB notification rate was higher than the average rate in the entire country.Methods:Space-time scan statistics were carried out using PTB registered data in the nationwide TB online registration system from 2011 to 2015,to identify spatial clusters.PTB patients diagnosed between October 2015 and February 2016 were selected and a structured questionnaire was administered to collect a set of variables that includes socio-economic status,behavioural characteristics,local environmental and biological characteristics.Based on the discovery of detailed town-level spatio-temporal PTB clusters,we divided selected subjects into two groups including the cases that resides within and outside identified clusters.Then,logistic regression analysis was applied comparing the results of variables between the two groups.Results:A total of 1508 subjects consented and participated in the survey.Clusters for PTB cases were identified in 38 towns distributed over south-western Zhaotong.Logistic regression analysis showed that history of chronic bronchitis(OR=3.683,95%CI:2.180-6.223),living in an urban area(OR=5.876,95%CI:2.381-14.502)and using coal as the main fuel(OR=9.356,95%CI:5.620-15.576)were independently associated with clustering.While,not smoking(OR=0.340,95%CI:0.137-0.843)is the protection factor of spatial clustering.Conclusions:We found PTB specially clustered in south-western Zhaotong.The strong associated factors influencing the PTB spatial cluster including:the history of chronic bronchitis,living in the urban area,smoking and the use of coal as the main fuel for cooking and heating.Therefore,efforts should be made to curtail these associated factors.

A progressive approach to predict shot peening process parameters for forming integral panel of Al7050-T7451

In this paper,a progressive approach to predict the multiple shot peening process parameters for complex integral panel is proposed.Firstly,the invariable parameters in the forming process including shot size,mass flow,peening distance and peening angle are determined according to the empirical and machine type.Then,the optimal value of air pressure for the whole shot peening is selected by the experimental data.Finally,the feeding speed for every shot peening path is predicted by regression equation.The integral panel part with thickness from 2 mm to 5 mm and curvature radius from 3200 mm to 16000 mm is taken as a research object,and four experiments are conducted.In order to design specimens for acquiring the forming data,one experiment is conducted to compare the curvature radius of the plate and stringer-structural specimens,which were peened along the middle of the two stringers.The most striking finding of this experiment is that the outer shape error range is below 3.9%,so the plate specimens can be used in predicting feeding speed of the integral panel.The second experiment is performed and results show that when the coverage reaches the limit of 80%,the minimum feeding speed is 50 mm/s.By this feeding speed,the forming curvature radius of the specimens with different thickness from the third experiment is measured and compared with the research object,and the optimal air pressure is 0.15 MPa.Then,the plate specimens with thickness from 2 mm to 5 mm are peened in the fourth experiment,and the measured curvature radius data are used to calculate the feeding speed of different shot peening path by regressive analysis method.The algorithm is validated by forming a test part and the average deviation is 0.496 mm.It is shown that the approach can realize the forming of the integral panel precisely.