Contact Profile Analysis of Resource Estimation Domains: A Case Study on a Laterite Nickel Deposit

Resource estimation is commonly performed in separate domains that are defined using different criteria depending on the type and geometry of the deposit, the mining method used, and the estimation method applied. The validity of estimation domains can be critical to the quality of produced resource estimates as they control various steps of the estimation process, including sample and block selection. Estimation domains also affect statistical and geostatistical analyses because they define what estimation practitioners will consider as statistically separate distributions of data. Sometimes, samples from different estimation domains share similar grade properties close to the contact between domains, a situation known as a soft boundary. In such cases, it can be useful to include samples from different domains at short distances from the boundary. Contact profile analysis is a technique that allows for the measurement of the relationship between grades on either side of the contact between two estimation domains. As discussed in the study presented in this paper, contact profile analysis can help validate the defined estimation domains and control the application depth of any soft boundaries found between domains.

Investigation of deformation of the cornea during tonometry using FEM

A three dimensional finite element model of the human eye is developed to evaluate the force which will be applied over the surface of cornea during tonometry and gonioscopy tests. The standard tonometers and gonioscopy experiences deformation from 0.5mm to 3mm of the cornea is adopted during both point contact and boundary contact on the surface of the cornea. The results demonstrate the maximum force experienced by the tonometer with point contact at the center of the cornea for the maximum possible deformation of the cornea during tonometry. The study also analyzes for the force experienced by the tonometer or goniolens with boundary layer contact for the defined deformation of the cornea along the direction from cornea towards the retina.

INTERPRETASI GEOFISIKA BIDANG GELINCIR PALEO-ROCKSLIDE PARANGTRITIS

Parangtritis has a rock fall hazard area with a medium to high level of risk. In Parangtritis, there was a large scale paleo-rockslide that involved more than 800 million m3 of rock mass with an area of 1500 m x 2700 m. This is a significant factor in changing the landscape. This research uses 9 Audio-MagnetoTelluric (AMT) primary data points. Using the distance between points 750 m within a 2 km x 2 km study area. The location focused on the western side of the paleo-landslide area in Parangtritis Village. Processing AMT data using the help of MT-INV and RockWorks software. The result of one-dimensional inversion consists of 3 layers. Indicates a low resistivity value (0-10 Ωm) interpreted as beach deposition and sand dune, medium resistivity (50 - 160 Ωm) for Wonosari limestone and high resistivity ( 170 Ωm) for Nglanggran andesite breccias. The average thickness of the first layer is 44 m and the second layer reaches 175 m. Based on the resistivity structure of the AMT data, the interpretation of the boundary contact between the Wonosari limestone and the Nglanggran andesite breccia can act as a slip field in a depth of about 250 m This field is a passive fault field controlled by the Girijati fault in the east of the study area.

Finite Element Modeling Method of Centrifugally Rotary Processing

In the present work, the process of interaction of an abrasive particle with the surface of a component is modeled in the framework of dynamic problems of the theory of thermoelasticity, considering plastic deformation, friction and wear of the surface in the contact region. Two boundary contact problems are considered. The first problem deals with the contact interaction of an element of an abrasive particle in the form of a truncated cone and the surface of a part. The circle of smaller diameter of the cone contacts the surface of the part taking into account the friction and plastic deformation of this surface. Kinematic or force boundary conditions are applied to the circle of greater diameter. In the case of kinematic conditions, the normal and tangential displacements of the circle and its rotation are specified. In the case of force conditions, the force and moment are given. In the second task, the hard stamp slides at a constant speed along the flat boundary of the workpiece, the value of the die insertion is set. In the contact area, the sliding friction force is expressed through normal pressure and heating due to the friction and wear. The stress and temperature fields near the contact region are investigated.

Influence of nonlinearities on the efficiency and accuracy of FEM calculations on the example of a steel build-up thin-walled column

Due to the increase of computing capabilities of standard processing units, it is possible to perform complex analyses, considering a number of nonlinearities, such as geometric, material and boundary (contact) even on personal computers. In the paper, the authors have analysed the efficiency and accuracy of standard PC’s FEM calculations performed in Abaqus CAE 2017 software on the example of a critical load assessment of a thin-walled steel column element with selected nonlinearities. A cross-section shape of a built-up column used by an international steel structures manufacturer was adopted. The analysis serves to check the behavior of their product. Several types of FEM analysis, strictly based on the EN standard regulations were performed. In turn, the relation of computational time to the adopted analysis type was obtained. Moreover, the produced load values in different types of independent calculation were compared and analysed. A possible future development in the field, based mainly on full-scale experimental tests, was also highlighted.