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Pollack Periodica
Authors: Bintul Zehra, Ali Salem, Souphavanh Senesavath, Saied Kashkash, and Zoltan Orban

Abstract

Concrete is the most widely used construction material in the world. Over ten billion tons of concrete are being produced each year resulting in exhaustion of natural materials and an enormous carbon footprint. One of the primary goals of concrete technology today is to reduce the use of Portland cement and natural fine aggregates by partially replacing them with various waste materials and by-products of industrial processes. The paper summarizes the results of a study where the partial replacement of river sand and Portland cement was successfully applied using steel slag aggregate, silica fume and glass waste.

Open access

Abstract

In this work, the thermal performance of using hybrid nanofluid of Ceria oxide and multi-walled carbon nanotube-based MOL 68 in the receiver tube of parabolic trough collector is simulated numerically. The influence of using this nanofluid under various volume concentrations and different Reynold numbers is solved numerically using computational fluid dynamics. The turbulent model's analysis is carried out based on kϵ re-normalization group and employed to find the Nusselt number and the heat transfer coefficients. The model results were validated with the previous correlation, which were used to evaluate the Nusselt number. The results showed that hybrid nanofluid enhances the heat transfer characteristics of the parabolic trough collector in comparison with the base fluid. Furthermore, even better heat transfer characteristics can be achieved with an increased volume concentration of the modified nanofluids.

Restricted access

Abstract

With the reform of China's childbirth policy in recent years, a unique baby boom phenomenon has emerged, and the new-born baby has increased rapidly in China. In the process of transformation and development of contemporary cities, a complex urban environment has a significant impact on psychology and physiology. The past kindergarten architectural aesthetic experience can no longer adapt to the social development needs. Thus, how to realize the sustainable development of kindergarten architecture has become a social problem that needs to be solved urgently. In the context of Environmental Psychology, this paper investigates the construction mode of experiential kindergarten architecture and tries to explore a new paradigm of educational architecture design in China for the future.

Open access

Abstract

The laser tracker is a widely used instrument in many industrial and metrological applications with high demand measurement accuracy. Imperfections in construction and misalignment of individual parts deliver systematic errors in the measurement results. All error sources need to be identified and reduced to the minimum to achieve the best possible accuracy. The paper summarizes error sources of the laser tracker without beam steering mirror with emphasis on error modeling. Descriptions of error models are provided for the static and kinematic type of measurement.

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Abstract

The city of Prishtina has constantly been changing in urban, architectural, and technological terms. This has political, ecological, economic, and cultural consequences, especially in the downtown area, where higher-density, taller office buildings and commercial spaces and even more congested residential areas are planned. In this study, the Urban Gastro-Lounge is taken as an example of an adaptive reuse strategy for a whole building or its interior. This example of adaptive reuse aims to revive urban and architectural areas as a way of promoting the sustainable development of the city in terms of its general formal architectural morphology. The Urban Gastro-Lounge is an excellent example of this approach and is worthy of being considered a particularly useful intervention.

Restricted access

Abstract

Microgrids (MGs) are capable to work at different operation modes, namely grid-connected or islanded, which make a significant change in the network fault current level. These changes may lead to problems and should be detected fast to do the proper protection actions accordingly and prevent blackouts. Moreover, some island detection methods suffer from the drawbacks of high computation burden and time-consuming procedure of training data to detect the islanded mode. For this purpose, in this paper, a faster and less computation burden island detection scheme without the need for training data is proposed which detects the islanded mode by analyzing the fault current data obtained from a continuous sampling using the phasor measurement unit (PMU). The sampled data are utilized in the fuzzy c-means (FCM) clustering to determine the network operation mode. The proposed scheme works in two phases. In the offline phase, the root mean square (RMS) of the current amplitude for islanded mode is determined, and in the online phase, the center of the measured data is compared to the RMS value to detect the MG operation mode at a decision making procedure. It is proved that the proposed island detection scheme is an applicable technique for detecting the islanded mode in MGs.

Open access

Abstract

In recent years, the importance of nanomaterials in food science, medicine, etc. has been increasing quickly. Herein, organic and inorganic red selenium nanoparticles synthesised by the reduction of sodium selenite with chemical and biological reducing agents. Grey hexagonal form in aqueous and powder was assembled at a high temperature of 85 °C for 10 min. Also, selenium enriched yogurt powder was made that contained about 2,000 mg kg−1 selenium, 93.8% of which is in nano form with a size of 50–500 nm. The synthesised nanoparticles were characterised by Dynamic Light Scattering Particle Size Analyzer (DLS), X-ray Diffraction Analysis (XRD), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). The prepared SeNPs could be promising additive for a wide range of applications.

Open access

Abstract

Tendencies of foodborne outbreaks show that the number of illnesses caused by Campylobacter spp. has been increasing recently in the European Union and in Hungary as well. However, the epidemiological statuses of Member States are diverse. There are several aspects to be investigated by competent authorities before the introduction of interventions. Methods supporting food safety decision making range from quick and easy techniques to complex, resource consuming approaches. The aim of the present study was the implementation of an evaluation and ranking system for a risk and its causes occurring in the broiler production chain. Data and information available in scientific literature were converted to a structured easy-to-use evaluation that supports decision making and helps structured data processing.

Open access

Abstract

The aim of this research was to assess the consumer habits of lactose sensitive persons in case of lactose-free products and their other shopping aspects for development of new, dairy-based lactose-free products. The research was based on face-to-face questionnaire survey, and those who declared to be lactose sensitive were analysed. Among them, only half of the women (49.3%) and one third of the men (34.6%) were medically proven lactose sensitive, so more than half of the respondents declared themselves affected on the basis of self-diagnosis. Our results show that reliably regular customers of lactose-free products are women and persons with medical diagnosis, high educational degree, and under the age of 30. The lactose-free consumer group prefers the following product features: lactose-free label; rich in calcium, vitamins, and fibre, and free of carbohydrate, sugar, and gluten. Only two-thirds of lactose sensitive customers (66.7%) consume lactose-free products regularly, so it can be assumed that the level of knowledge of this disease, its treatment, and the importance of lactose-free dairy products among these persons is insufficient. This could be solved with education, advertisement, and other information opportunities.

Open access

Abstract

Mathematical methods take an important part in reconstruction technologies of radiographic image. Back projection, iterative, and analytical (Two-dimensional Fourier, Filtered Back Projection) methods are the most important procedures for image reconstruction. Whenever there exists numerous projections, analytical methods have a great performance in speed and accuracy and due to these advantages they are comprehensively used for X-ray imaging. One of the widespread used methods in tomographic image reconstruction is Filtered Back Projection (FBP) algorithm. This paper presents an application of this reconstruction algorithm for a generated image of the object. Shepp-Logan filter is used to form the filtered back projection image and performance improvement is investigated. The obtained images indicate that FBP algorithm can be substantial for various applications in the field of medicine and industry.

Open access