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  • Author: Mariusz Barczak x
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An effective scaling frequency factor method (ESFF): review and local factors transferability problem

Abstract

Scaling procedures are known to reproduce very accurate vibrational spectra provided that multiparameter scaling in conjunction with high-quality force fields is carried out. In contrast to purely theoretical approaches (variational and perturbational), they are applicable to large systems. In this work, a brief review of the scaling procedures is given. The emphasis is put on the recently proposed effective scaling frequency factor (ESFF) method [Chem. Phys. Lett., 446, 191, (2007), J. Mol. Spectr., 264, 66, (2010)] - the multiparameter frequency scaling method providing better scaled frequencies than the well-established scaled quantum mechanical (SQM) force field approach. In addition, the results of our calculations on the benzene-based related systems, i.e., benzene and most of its methyl derivatives, are presented. The calculations concern the middle- and low-frequency range of the vibrational spectra, where strong mixing of the local vibrations often takes place. The factors transferability problem is discussed.

Open access
Synthesis and Characterization of Activated Carbons Obtained from Nutshells

Abstract

Walnut and hazelnut shells were used to prepare activated carbons using potassium hydroxide as an activation agent. The obtained activated carbons presented a specific surface areas of 1661 and 1322 m2/g and pore total volumes of 0.80 and 0.65 cm3/g, respectively. Moreover, the obtained activated carbons presented high quantity of micropores in their structure and that is why they have a great potential for environmental applications and they could be an alternative to commercially available activated carbons from the viewpoint of adsorption capacity. This paper proves that walnut and hazelnut shells have got a large potential as precursors to obtaining activated carbons and they could be successfully converted into a well-developed porous materials by chemical activation.

Open access
Nanoporous Silica-Based Materials for Sorption of Pharmaceuticals and Biomolecules

Abstract

Our concern in this paper is to review four kinds of mesoporous silica materials which can be used as potential sorbents for pharmaceuticals. It is known that a continuous development of science, medicine and food industry has an effect on contamination of the natural environment. Moreover, many impurities, such as drugs, vitamins or proteins etc., which get into environment from urban and hospital wastes, can also influence on human organisms. Thus, there is a need to control an amount of those compounds, especially in the natural waters and wastewaters [1-4]. In this work, we present four types of silica materials which can be helpful in water purification by using adsorption process.

Open access
Food Safety Challenges in the Tourism Processes

Abstract

The modern food industry is among the key partners of today’s global tourism. As part of the tourism processes, tourists buy and consume local food in the local catering facilities. Furthermore, tourists are usually willing to try out gastronomy specialties during their travels. Food safety is important for tourists although it is not always part of their conscious behavior in the destination. Food safety standards are regulated by international contracts based on the analysis of more half a century’s experiences. Within processes related to the changes in the external environment, there are emerging issues – although in different intensity - like chemical and microbiological contamination or food terrorism. Due to the immense number of participants in tourism, it is of key importance to raise awareness of threats like food decay, infections and other negative impacts, because food safety if a basic need in all tourism destinations. The amount of waste food is increasing dramatically at a global scale. The study will introduce the findings of a food safety research in Hungary, providing useful knowledge to all stakeholders of the tourism industry.

Open access