The paper describes a resistor network for linearity verification of voltage ratio indicating instruments. The network is a based on a resistive divider with low variation of input and output resistance. To compensate for the output resistance change due to selection of various output ratios, a switched variable compensating resistor network is added to output leads of the voltage divider. It limits the variation of output resistance to below 5 % at ratio 1:10 and below 0.5 % for ratios 1:100 and above. The application of the circuit is shown in the example of output voltage ratio simulation of a strain gauge bridge transducer, typical for measurement of mechanical quantities such as force, torque and pressure. The circuit is suitable for verification of linearity of voltage ratio measuring instruments by employing combinatorial calibration technique without the need to calibrate the resistor network. Results are shown for linearity check of high precision strain gauge amplifiers.
F.09 Development of a new technological process or technology
COBISS.SI-ID: 2107239A number of green concrete mixes having similar basic properties were evaluated from the environmental point of view by means of the Life Cycle Assessment method, and compared with a corresponding conventional concrete mix. The investigated green concrete mixes were prepared from three different types of industrial by-products, i.e. (1) foundry sand, and (2) steel slag, both of which were used as manufactured aggregates, and (3) fly ash, which was used as a mineral admixture. Some green concrete mixes were also prepared from a recycled aggregate, which was obtained from reinforced concrete waste. In some of the green concrete mixes the recycled aggregate was used in combination with the above-mentioned types of manufactured aggregate and fly ash. All of these materials are able, to some extent, to replace natural aggregate or Portland cement in concrete mixes, thus providing an environmental benefit from the point of view of the saving of natural resources. Taking into account consequential modelling, the credit related to the avoidance of the need to dispose of the waste materials is considered as a benefit. In case of the recycling of waste concrete into aggregate, credit is attributed to the recovery of scrap iron from the steel reinforcement. In the case of the use of steel slag, credit is attributed to the recovery of metals, which are extracted from the slag before being used as an alternative material. The disadvantage of using alternative materials and recycled aggregates can sometimes be their relatively long delivery distance. For this reason, a transport sensitivity analysis was carried out. The results indicate that the use of the discussed alternative and recycled materials is beneficial in the concrete production industry. Preference is given to the fly ash and foundry sand scenarios, and especially to those scenarios which are based on the combined use of recycled aggregate with these two alternative materials. It was found that longer delivery distances of the alternative materials do not necessarily affect the results significantly. However, variable delivery distances may have a greater effect when choosing between different alternative scenarios.
F.02 Acquisition of new scientific knowledge
COBISS.SI-ID: 2122599In order to achieve significant savings in energy and an improved level of thermal comfort in retrofitted existing buildings, specific retrofitting concepts that combine new technologies and design need to be developed and implemented. Large radiant surfaces systems are now among the most promising future technologies to be used both in retrofitted and in new low-energy buildings. These kinds of systems have been the topic of several studies dealing with thermal comfort and energy utilization, but some specific issues concerning their possible use in various concepts for retrofitting are still poorly understood. In the present paper, some results of dynamic simulations, with the transient system simulation tool (TRNSYS) model, of the retrofitted offices equipped with radiant ceiling panels are presented and thoroughly analysed. Based on a precise comparison of the results of these simulations with actual measurements in the offices, certain input data for the model were added, so that the model was consequently validated. The model was then applied to the evaluation of various concepts of building envelopes for office retrofitting. By means of dynamic simulations of indoor environment it was possible to determine the benefits and limitations of individual retrofitting concepts. Some specific parameters, which are relevant to these concepts, were also identified.
F.10 Improvements to an existing technological process or technology
COBISS.SI-ID: 2148199In addition to seismic events, climate changes - which are reflected in extreme events such as heat and cold waves, storms, floods, landslides, mud-slides and avalanches, can cause irreversible damage to cultural heritage. Although predicting the occurrence of natural and human disasters and their perimeter is not trivial, the increasing impact of extreme events requires critical evaluation of prevention strategies, immediate response and rehabilitation measures. This work aims to discuss the general characteristic features of natural disasters and their impact on cultural heritage focusing on damage to vernacular timber structures in (summer) storms. The study is based on the analysis of damage identified in summer storms in Slovenia in 2008. Possible mitigation and repair strategies are furthermore discussed.
F.27 Contribution to preserving/protecting natural and cultural heritage
COBISS.SI-ID: 2115943The paper presents an automatic procedure for the correction of bridge weigh–in-motion (B-WIM) measurements, which are used to determine the axle loads of heavy vehicles using instrumented bridges. According to the European Specifications for Weigh-in-Motion criteria, using this procedure the weighing results could be improved by up to one accuracy class. Whereas measurements performed on steel structures provide reliable information about the global behaviour of individual bridges, which is accounted for in the B-WIM algorithms, cracks that are present in concrete structures can, depending on their locations with respect to installed strain transducers, amplify or reduce the response. In the present work special care was taken to detect and calibrate any strain transducer which showed a disproportional response. The accuracy of the method was investigated numerically in relation to the extensive data which were available in the case of a reinforced concrete bridge (motorway underpass), located near Ljubljana, Slovenia, and then validated by a one-to-one comparison of the B-WIM weighing results and the statically weighed test vehicles.
F.10 Improvements to an existing technological process or technology
COBISS.SI-ID: 7254113