In the last few decades, several rock mass classification systems have been proposed to identify rock slope stability conditions, having high probability of failure and accordingly prioritize ...preventive measures. This paper reviews the various classification systems, highlighting their differences and similarities with regard to the factors involved and the mode of their failures. The advantages and limitations of each classification have also been compared. However, many of these existing systems fail to classify slope cuttings according to their actual vulnerability of failure, as they ignore important triggering factors such as earthquakes or precipitation. For example groundwater is considered as an instability causing factor with limited effect, rather than a triggering factor for failure. It is observed that rock slope should be classified according to their potential of failure, taking into account both their condition and the influence of triggering factors upon stability. It is also observed that it is important to analyse each type of failure separately, since each one is influenced by unique factors of instability. Finally, it provides suggestion for the improvement of existing classifications through incorporation of all the critical factors like slope aspect, mode of excavation, earthquake, and rainfall that would have caused slope instability.
Space-based observation of crops and agro-system on the Earth surface is one of the most important applications of remote sensing using the sensors in optical and microwave spectrum to assess the ...crop growth for decision making for developing crop information and management system. Remote sensing technology provides scalable and reliable information in respect of rice crop grown area, its crop growth and prediction of crop yield due to acquisition of satellite imagery during the revisit of the orbit by space-borne sensors in optical and microwave spectrum. Synthetic Aperture Radar has the advantages of all-weather, day and night imaging, canopy penetration, and high-resolution capabilities, which makes Space-borne SAR sensors as an effective system for monitoring crop growth, crop classification and mapping of crop area based on the crop canopy interaction of SAR signals due to backscattering coefficients of the earth surface. SAR data from ERS-1/2 SAR, ENVISAT ASAR, ALOS-1/2 PALSAR, Radarsat-1/2 SAR, TerraSAR, COSMO-SkyMed, and Sentinel-1 have been used by various researchers for identification and analysis of rice crop growth based on the backscattering values in different regions of Asia and European region, where backscattered image depends of various earth surface and SAR sensors parameters. In this paper, knowledge based classifier using SAR images of existing space-borne-SAR sensors have been developed based on modeling of SAR backscattering coefficients in C-band and X-band for monitoring the rice crop growth and its analysis using multi-temporal and multi-frequency- SAR sensors data.
Stabilization of a D022 Phase in Ni–Cr–Mo–W–Ti Alloys Verma, A.; Singh, J. B.
Metallurgical and materials transactions. A, Physical metallurgy and materials science,
10/2021, Letnik:
52, Številka:
10
Journal Article
Recenzirano
Ni–Cr–Mo alloys mostly form precipitates of the Ni
2
(Cr,Mo) phase. A D0
22
phase with Ni
73.2
Cr
7.4
Mo
9.0
W
1.8
Ti
8.6
composition has been stabilized in a Ni–Cr–Mo alloy by the addition of W and ...Ti in a judicious manner that retards the precipitation of the Ni
2
(Cr,Mo) phase. The D0
22
phase remains thermally stable up to 800 °C. The fast age-hardening response of the D0
22
phase opens up the possibility of a new series of high strength age-hardenable Ni–Cr–Mo alloys.
Traditional fault tree (FT) analysis is widely used for reliability and safety assessment of complex and critical engineering systems. The behavior of components of complex systems and their ...interactions such as sequence- and functional-dependent failures, spares and dynamic redundancy management, and priority of failure events cannot be adequately captured by traditional FTs. Dynamic fault tree (DFT) extend traditional FT by defining additional gates called dynamic gates to model these complex interactions. Markov models are used in solving dynamic gates. However, state space becomes too large for calculation with Markov models when the number of gate inputs increases. In addition, Markov model is applicable for only exponential failure and repair distributions. Modeling test and maintenance information on spare components is also very difficult. To address these difficulties, Monte Carlo simulation-based approach is used in this work to solve dynamic gates. The approach is first applied to a problem available in the literature which is having non-repairable components. The obtained results are in good agreement with those in literature. The approach is later applied to a simplified scheme of electrical power supply system of nuclear power plant (NPP), which is a complex repairable system having tested and maintained spares. The results obtained using this approach are in good agreement with those obtained using analytical approach. In addition to point estimates of reliability measures, failure time, and repair time distributions are also obtained from simulation. Finally a case study on reactor regulation system (RRS) of NPP is carried out to demonstrate the application of simulation-based DFT approach to large-scale problems.
One of the most significant challenges of construction of underground large size structures is to determine the effect of the geological discontinuities. Fault is a natural discontinuity which allows ...significant displacement of the rock mass along the fault plane and increases the plastic zones around the underground structure. For instance, an underground hydropower plant comprising more than two underground caverns and large distance between the underground cavern incurs the higher cost because of connecting tunnels or transfer of electricity from powerhouse cavern to transformer cavern. However, presence of the fault would result in the increase of the plastic zone and shear displacement along the fault. Thus, with regards to the effect of the fault on the stability of the two parallel caverns, in this paper different numerical models were simulated to study the effect of the fault on plastic zone around the cavern group and pillar between the caverns, and shear displacement along the fault plane under different scenarios such as fault location, fault dip angle, fault friction angle and in-situ stress conditions. The results are produced graphically and discussed. These results offer advance guidelines in construction of the two parallel large size caverns.
Crystalline rocks are the best-suited rock type for the nuclear waste repository. A deeper understanding of the thermomechanical stability of rocks plays a crucial role in the selection of suitable ...host rock for this purpose. To investigate the feasibility of different types of Jalore granitoid rocks (red, pink, golden, and white granites) in this application. The main objective of this study is devoted to damage characteristics when selecting the potential rock, while little work has been done in the field of rock mechanical behaviors in particular nuclear waste disposal. Where rock needs to stable after undergoing increases in the number of the thermal cycle in the treatment if a below damage threshold temperature is applied as in this study (i.e., 250 °C). The rock specimens were heated till 250 °C for 12 h, with constant heating rate 5 °C/min and constant cooling rate 0.364 °C/min, up to nine cycles. In this paper, the stress–strain curve under tension (Brazilian disc test) was plotted for Jalore granitoid rocks after different thermal cycle treatment. Using Lemaitre’s strain equivalent principle along with statistics and damage theory, a model for damage caused due to thermal cycles under indirect tension condition is established. We have also measured the microscopic observation (thin section), mineral characterization (XRD), and surface morphology (SEM) of different thermal cycles treated. Thermogravimetric analysis (TGA) and differential thermal analysis (DT) have also been used to identify the changes in thermal and kinetic behaviors. It is found that the increase of the thermal cycle leads to an accumulation in strains and a reduction in the P-wave velocity and rock strength. We have found that the thermal damage incurred on the rock, in the form of mass loss and P-wave velocity decrease, due to thermal cracks and nonuniform expansion of grains along the grain boundary were developed on the surface. Increasing thermal cycles lead to a reduction in tensile strength and elastic modulus. Fracturing within the rock is more severe, as compared to three cycles, after being subjected to five thermal cycles. It is interesting to note that beyond five cycles of thermal treatment, the thermal damage and stability of the granitoid have remained mostly unchanged.
The present study was conducted to evaluate the genetic variability for morphological and qualitative traits of Coccinia for development of trait specific lines at ICAR-Central Horticultural ...Experiment Station (CIAH-RS), Panchmahals (Godhra), Gujarat during 2020-2022. In this study, we evaluated 26 gynoecious accessions to assess the genetic divergence through principal component and cluster analysis. The experiment was carried out in a randomized complete block design with three replications under rainfed semi-arid conditions. High values of PCV and GCV were observed for variables such as NFFP (25.13 and 22.20), PL (23.14 and 20.69), FD (24.01 and 21.46), AFW (22.98 and 20.13), NFPY (26.38 and 24.40), FYP (37.57 and 31.29), FY (35.55 and 33.20), AsC (28.65 and 27.73), Ac (24.32 and 21.06), TSS (37.23 and 35.94), DPPHL (20.71 and 20.38), FRAPL (21.08 and 20.92), TPF(20.81 and 20.45) respectively. High heritability coupled with high genetic advance as per cent of mean was observed for vine length (VL), internodal length (IL), number of female flowers per plant (NFFP), fruit length (FL), peduncle length (PL), fruit diameter (FD), average fruit weight (AFW), number of fruit per plant per year (NFPY), fruit yield per plant (FYP), fruit yield (FY), ascorbic acid (AsC), acidity (Ac), total soluble solids (TSS), total phenols in leaves TPL), total flavonoids in leaves TFL, CUPRAC in leaves (CUPRACL), DPPH in leaves (DPPHL), FRAP in leaves (FRAPL), Total phenols in fruits (TPF), Total flavonoids in fruits (TFF), CUPRAC in fruits (CUPRACF) and DPPH in fruits (DPPHF). The FYP exhibited a significant positive correlation with variables like VL (0.6833), IL (0.2991), NFFP (0.8107), FD (0.5245), AFW (0.6766), NFPY (0.7659), ASC (0.4611), TSS (0.5004) and TPF (0.4281). The estimates of genetic parameters revealed scope for further improvement of fruit yield by selection. Of the eight principal components, PC-I through PC-VIII had eigen values greater than 1 and it accounts 85.02% of the total variation for 26 gynoecious accessions of Ivy gourd. The eigen values of PC-I comprised 5.775% of total variation followed by PC-II (4.250%), PC-III (3.175%), PC-IV (2.588%), PC-V (1.828%), PC-VI (1.447%), PC-VII (1.179%) and PC-VIII (1.013%).The cluster VI and cluster I having highest mean values for most of traits under study. Thus, genotypes from the distinct cluster like cluster VI and I for should be used for selection of parents and varietal improvement for further breeding programme in ivy gourd.
Patient characteristics, clinical care, resource use and outcomes associated with admission to hospital for coronavirus disease 2019 (COVID-19) in Canada are not well described.
We described all ...adults with COVID-19 or influenza discharged from inpatient medical services and medical-surgical intensive care units (ICUs) between Nov. 1, 2019, and June 30, 2020, at 7 hospitals in Toronto and Mississauga, Ontario. We compared patient outcomes using multivariable regression models, controlling for patient sociodemographic factors and comorbidity level. We validated the accuracy of 7 externally developed risk scores to predict mortality among patients with COVID-19.
There were 1027 hospital admissions with COVID-19 (median age 65 yr, 59.1% male) and 783 with influenza (median age 68 yr, 50.8% male). Patients younger than 50 years accounted for 21.2% of all admissions for COVID-19 and 24.0% of ICU admissions. Compared with influenza, patients with COVID-19 had significantly greater in-hospital mortality (unadjusted 19.9% v. 6.1%, adjusted relative risk RR 3.46, 95% confidence interval CI 2.56-4.68), ICU use (unadjusted 26.4% v. 18.0%, adjusted RR 1.50, 95% CI 1.25-1.80) and hospital length of stay (unadjusted median 8.7 d v. 4.8 d, adjusted rate ratio 1.45, 95% CI 1.25-1.69). Thirty-day readmission was not significantly different (unadjusted 9.3% v. 9.6%, adjusted RR 0.98, 95% CI 0.70-1.39). Three points-based risk scores for predicting in-hospital mortality showed good discrimination (area under the receiver operating characteristic curve AUC ranging from 0.72 to 0.81) and calibration.
During the first wave of the pandemic, admission to hospital for COVID-19 was associated with significantly greater mortality, ICU use and hospital length of stay than influenza. Simple risk scores can predict in-hospital mortality in patients with COVID-19 with good accuracy.
Copper nanoparticles (CuNPs) in aqueous medium were prepared with alkaline hydrazine hydrate as the reductant and PVP as the stabilizing agent without any inert gas protection. Careful variation in ...the amount of reductant resulted in formation of two stable CuNPs dispersions with different average sizes and consequently different localized surface plasmon resonance absorbances. These two as-synthesized CuNPs dispersions were used to catalyze the model
p
-nitrophenol reduction reaction. The kinetics of reduction was monitored as a function of concentration and temperature of reactants. Using this we determined the activation energy, pre-exponential factor and the entropy of activation for the two types of CuNPs samples. Catalytic activities of the CuNPs were found to be affected mainly by their activation energies.
Graphical Abstract
PDF
