Critical Value of CO of Forecasting Coal Spontaneous Combustion

CO has been used widely in the production process of colliery as an index gas to predict spontaneous combustion of coal. But in some collieries there are CO gas in the upper corner of the face all the times, sometime CO gas even exceeds the regulated critical index. This phenomenon is much more obvious in the fully-mechanized longwall face and fully-mechanized longwall and top-coal caving face. Although many measures of fire-proof and fire-extinguishing have been adopted, the flowing amount of CO gas can be only decreasd, but can not be eliminated completely. Using the different kinds of coal, the experiment of coal oxidation was made at the low temperature. The experiment indicates that some kinds of coal can produce CO under the condition of normal temperature oxidation, sometime the CO consistency is very high, and the intension of CO can be decreased with oxidation time prolonging. Selecting rational critical value of CO is the kev to predicting spontaneous combustion of coal correctly and reliably. The problem of selecting retional critical value of CO was studied. Finally, the amount of CO gas released by different kinds of coal was obtained under normal temperature condition.

The Criticality Indices of Activities in PERT

In this paper, we present a direct computing method of the Criticality Index (CI) of the activities in PERT networks. The method is no needed for determining CI of all the paths in a PERT network, and the CI of all the activities can be estimated by computing CI of a small portion of the activities. We give the series of conclusions and computation formulas for computing the CI of activities, and the computing algorithm for the above mentioned conclusions has been applied to large size PERT network. The results are found to be very close to those obtained by extensive Monte Carlo sampling.

Mutual Interference of Two Debris Flow Deposits Delivered in a Downstream River Reach

We investigate experimentally the depositions of two contiguous debris flows flowing into a main river reach.The aim of the present experimental research is to analyze the geometry and the mutual interactions of debris flow deposits conveyed by these tributaries in the main channel.A set of 19 experiments has been conducted considering three values of the confluence angle,two slopes of the tributary,and three different triggering conditions(debris flows occurring simultaneously in the tributaries,or occurring first either in the upstream or in the downstream tributary).The flow rate along the main channel was always kept constant.During each experiment the two tributaries had the same slope and confluence angle.The analysis of the data collected during the experimental tests indicates that the volume of the debris fan is mainly controlled by the slope angle,as expected,while the shape of the debris deposit is strongly influenced by the confluence angle.Moreover,in the case of multiple debris flows,the deposit shape is sensitive to the triggering conditions.Critical index for damming formation available in literature has been considered and applied to the present case,and,on the basis of the collected data,considerations about possible extension of such indexes to the case of multiple confluences are finally proposed.

Experimental study on stability of sunken large diameter cylindrical structure on sandy seabed during construction period

A systematic experimental research work is done for the stability of sunken large diameter cylinder during construction period. It is the first research that gives the method for assessing the stability of the larger diameter cylindrical structure, a set of values is derived also for the critical stability indices of the large diameter cylinder sunken to the sandy seabed.

Significant Improvement in Rainfall Forecast over Delhi:Annual and Seasonal Verification

Regional Weather Forecasting Centre(RWFC)New Delhi has the responsibility to issue and disseminate rainfall forecast for Delhi.So it is very important to scientifically verify the rainfall forecast issued by RWFC.In this study rainfall forecast verification of Delhi has been carried out annually and season wise for the period 2011 to 2021.Various statistical parameters such as Percentage Correct(PC),Probability of Detection(POD),Missing Ratio(MR),False Alarm Ratio(FAR),Critical Success Index(CSI),True Skill Statistics(TSS)and Heidke Skill Score(HSS)have been calculated for season wise and annually.A forecast is considered to be improved if PC,POD,CSI,TSS and HSS increase and FAR and MR decrease over a period of time.The author can conclude that annual accuracy of forecast has increased significantly over the period of time from 2011 to 2021,as PC,POD,CSI,TSS and HSS increase and FAR and MR decrease over a period of time.Maximum contribution in the improved forecast has observed in transition season(pre-monsoon season followed by post-monsoon,having rainfall activity mainly in association with thunderstorms),when FAR and MR have decreased drastically.

Almost Everywhere Convergence of Riesz Means on Noncompact Symmetric Space SL(3,H)/SP(3)

Let G/K be the noncompact Riemannian symmetric space SL(3, H)/Sp(3). We shall prove in this paper that for f∈L^P(SL(3, H)/Sp(3)), 1≤p≤2. the Riesz means of order z of f with respect to the eigenfunctions expansion of Laplace operator almost everywhere converge to f for Rez】б(n, p). The critical index δ(n,p) is the same as in the classical Stein’s result for Euclidean space. and as in the noncompact symmetric spaces of rank one and of complex type.

Existence and Multiplicity of Solutions for Nonlocal Systems with Kirchhoff Type

Firstly,we use Nehari manifold and Mountain Pass Lemma to prove an existence result of positive solutions for a class of nonlocal elliptic system with Kirchhoff type.Then a multiplicity result is established by cohomological index of Fadell and Rabinowitz.We also consider the critical case and prove existence of positive least energy solution when the parameter β is sufficiently large.