Virtual reality and its possible integration into the process of distance learning focused on technically oriented subjects

Individual digital technologies which are aimed at simulation of real world elements are currently one of the most promising areas of interest. The growing popularity of the augmented, virtual reality technologies, as well as the industries in which their application has an increasing impact, is causing a sharp growth in the number of specialized software. An increasingly popular sector in which virtual and augmented reality has promising prospects in the field of education. It was this area that created space for the application of various software solutions during a pandemic situation. The application focused on the distance form of educational process, training and mediation of interactive experiences, which subsequently mitigate the teaching process, has found application not only in technically oriented areas. This article presents the possibilities for usage of the virtual environment created in the Rinoceros software, which is used as a supporting tool for the teaching process of technically oriented subjects. The article describes how to apply and modify specialized software for a specific area of use. Particular type of VR/AR devices are used to mediate an interactive form of teaching, towards a specific group of students. Due to the intention of increased efficiency of this process, the article presents the possibilities of using the multiuser - host/guest functions, for full interactivity of more users. This solution allows the users to work with 2D, 3D models and CAD model assemblies in a virtual environment. It also presents the possibilities and promising areas of use which describe the other software features and their possible application in other areas, such as reverse engineering and intuitive modeling.

Evaluation of Specific Administering Devices for Antineoplastic Drugs Compounded in Syringes in Paediatry: Methodology Proposal

Purpose The aims of this study were to propose a simple methodology to assess the rinsing volume of syringe extension sets and to compare several marketed devices. Methods A UV-spectrophotometry assay using quinine hydrochloride as drug substitute was developed. Quinine concentration ranged from 20 to 200 µg/ml. The assay was validated with the accuracy profile method and tested on five different assemblies (device+extension sets) with different dead-space volumes (1.28–2.80 ml) and at two different quinine concentrations (0.3 and 8.0 mg/ml). Rinsing was performed stepwise with water for injection until reaching an undetectable quinine concentration. After fitting the data with a Weibull model, assemblies were compared with an ANOVA performed on ranks (GraphPad, La Jolla, USA). Results The within-day and between-day precision ranges were 0.39–0.81 and 0.48–0.84%, respectively. The lower limit of quantification was 4.26 µg/ml. The volume required to completely rinse the infusion line was different according to the initial drug concentration and to the device assessed: from 6 to 10 ml for a low quinine concentration and from 7 to 17 ml for a high quinine concentration. Conclusion This study shows that a simple, cheap and easy-to-use methodology may be used to assess the rinsing volume of syringe extension sets. The rinsing volume is different according to the tested device.

Considerations About the Necessary Mesh Density of Bearings in Detailed Finite Element Models

In order to predict properly the behavior of very complex mechanical models, much focus needs to be done on the level of model details as well as the techniques used to predict component movements based on mechanical and thermal loads. In particular bearings and joints play a significant role in big model assemblies such as aero-engines where most of the structures are modeled by solid elements rather than using traditional shell or beam elements. This approach is very complex and expensive in terms of computational effort however can lead to increased simulation accuracy when done properly. This publication will answer questions related to the modeling techniques required for detailed bearings (not only rotor bearings) and joints of an aero-engine application where these components are not idealized or simplified, i.e. the ball in a ball joint is meshed by solid elements. The investigation will discuss the question about the number of elements needed to mesh a ball joint in such a way that a correct rotation is possible. If the mesh is too coarse, a rotation would be impossible due to the faceting of the rotating parts. It will be shown that a proper rotation depends on a correct relation between the radius of the inner ball, the gap size of the bearing and the number of nodes in the circumferential direction. For this relation an analytical formula has been derived and successfully tested at some examples. Furthermore, some finite element codes offer the possibility of smoothed contact surfaces. These options improve the situation but they might cause issues too. For this reason these smoothed contact options are also considered under the aspects mentioned above.

A Sensitivity Approach for Eliminating Clashes From Computer Aided Design Model Assemblies

Clashes occur when components in an assembly unintentionally violate others. If clashes are not identified and designed out before manufacture, product function will be reduced or substantial cost will be incurred in rework. This paper introduces a novel approach for eliminating clashes by identifying which parameters defining the part features in a computer aided design (CAD) assembly need to change and by how much. Sensitivities are calculated for each parameter defining the part and the assembly as the change in clash volume due to a change in each parameter value. These sensitivities give an indication of important parameters and are used to predict the optimum combination of changes in each parameter to eliminate the clash. Consideration is given to the fact that it is sometimes preferable to modify some components in an assembly rather than others and that some components in an assembly cannot be modified as the designer does not have control over their shape. Successful elimination of clashes has been demonstrated in a number of example assemblies.

Modelling of Grain Microstructure of IN-713C Castings

This paper provides an analysis of experimental research results and numerical simulation of grain microstructure of turbine blade castings made of the IN-713C nickel superalloy. The numerical simulation was carried out by applying the ProCAST program. The geometric description of model assemblies and three-dimensional ceramic mould enclosure was developed. The boundary conditions as well as the thermal and physical coefficients for alloy and ceramic shell mould were selected for simulation purposes. The parameters of nucleation law based on normal (Gaussian) distribution as well as the values of equation coefficients were established in order to determine the growth rate of dendrite tips for the IN-713C alloy, depending on the undercooling. The experimental verification of boundary conditions for numerical simulation was carried out by comparison with the results of temperature distribution measurements performed in the castings. The analysis of grain microstructure was conducted on the surface and cross-sections of castings. The forecasted grain microstructure was determined using the CAFE module (ProCAST software). The cast microstructure as well as the value of grain growth and nucleation coefficients, which were used for numerical simulation of solidification process, were experimentally verified.

Using the object modeling system for hydrological model development and application

State of the art challenges in sustainable management of water resources have created demand for integrated, flexible and easy to use hydrological models which are able to simulate the quantitative and qualitative aspects of the hydrological cycle with a sufficient degree of certainty. Existing models which have been de-veloped to fit these needs are often constrained to specific scales or purposes and thus can not be easily adapted to meet different challenges. As a solution for flexible and modularised model development and application, the Object Modeling System (OMS) has been developed in a joint approach by the USDA-ARS, GPSRU (Fort Collins, CO, USA), USGS (Denver, CO, USA), and the FSU (Jena, Germany). The OMS provides a modern modelling framework which allows the implementation of single process components to be compiled and applied as custom tailored model assemblies. This paper describes basic principles of the OMS and its main components and explains in more detail how the problems during coupling of models or model components are solved inside the system. It highlights the integration of different spatial and temporal scales by their representation as spatial modelling entities embedded into time compound components. As an exam-ple the implementation of the hydrological model J2000 is discussed.