For an interdisciplinary approach on different topics of medicinal and analytical chemistry, we applied a known experimental pKa value determination method on the field of the bench top nuclear ...magnetic resonance (NMR) spectrometry of some known biologically active pyridine-based drugs, i.e., pyridoxine hydrochloride, isoniazid, and nicotine amide. The chemical shifts of the aromatic ring protons in the 1H NMR spectrum change depending on the protonation status. The data were analyzed on dependence of the chemical shifts by different pH (pD) environments and then the pKa values were calculated. The pKa values obtained were in agreement with the literature data for the compounds, searched by the students on web programs available at our university. The importance of the pKa values in protein-ligand interactions and distribution etc. of drugs was brought up to the students’ attention. In addition, by the use of a free web application for pKa values prediction, students calculated the predicted modeled pKa value. The experimental and in-silico approaches enhance the tool box for undergraduate students in medicinal chemistry.
The monitoring and the control of air pollution which is a consequence of the activities of district heating plants in the area of Niš have indicated that there is a cause and effect relationship ...between the emitted pollutants and air quality on one hand, and health risk on the other hand. The aim of this paper is to determine the correlation between district heating plants, air quality and health risk. The evidence of this connection is the hazardous health quotient and the level of total carcinogenic risk in comparison to measured immission concentration and expected immission concentrations of pollutants from district heating plants in the city.
Vibration analysis of the repaired well pump is to determine whether vibrations occur due to an insufficient pump repair or due to some new malfunction that happened after the repair. This paper ...presents vibration analysis of well pump as well as the applied corrections in order to lower the vibration levels. Vibration measurement of well pump is conducted on measurement points defined by standard ISO 10816-1.
Climate chambers are a complex system of electromechanical components used for conditioning of air for providing comfort and projected parameters of temperature, humidity, velocity and air ...cleanliness in the area. In this paper is presented examination of the fan unit company Flaktwoods GJLB-5-071, 17.95 kW, n=1450 rpm, with a multi-functional device Vibrotest 60, the Danish manufacturer Bruel & Kjaer, for diagnostic of parameters of vibration and condition of bearing. The measured parameters are related to: - levels of vibrations (including measurement points on the motor and on the fan) in the directions of coordinate axes, according to ISO 10816-1. - parameters of condition of bearing through the index of bearing condition BCU (Bearing Conditions Unit) and BCS (Bearing Spectrum Conditions) - analysis of the characteristic frequency of vibration in the spectrum, presented by FFT (Fast Fourier Transformation).
This paper shows an example of computer simulation of hybrid vehicle in two different driving modes. This example shows multiple areas of operation of a simulated hybrid electric vehicle. The hybrid ...electric vehicle is of combined type, similar to Toyota Prius cars. This hybrid electric vehicle has two types of driving power: the electric motor and the internal combustion (IC) engine, to increase the level of efficiency of driving assembly and to reduce air pollution. A hybrid electric vehicle combines the advantages of electric motor drive (no pollution and high available power at low speeds) and the advantages of IC engine (high dynamic performances and little pollution at high speeds). In the simulation of a hybrid electric vehicle SimPowerSystems™ and SimDriveline™ (MATLAB) were used.
Polazeći od fi lozofskih misli O. Spenglera i Aristotela, utvrđeno je da su polimeri prastari, jer sežu tamo do postanka osnovnih prirodnih organskih i anorganskih polimera. Istodobno je uočeno da se ...riječ polimeri učestalo upotrebljava kao zajedničko ime za plastiku i elastomere. Od osnovnih prirodnih organskih polimera: bjelančevina, nukleinskih kiselina i polisaharida dug je povijesni put. Taj se put pokušalo opisati dijagramom toka, tokovnikom. Za navedeni opis potrebne su brojne defi nicije, ali i motivacijska osnova. To je učinjeno u dodatcima A i B. Zaključak je istraživanja: praoblikovanje i prastrukturiranje prirodnih polimera staro je oko 3,5 milijardi godina, a humana obradba razdvajanjem oko 3,4 milijuna godina. Svatko tko se bavi polimerima trebao bi biti obrazovan na odgovarajućoj razini potrebnog znanja s razvijenim tokovnikom.
Nowadays, besides the conventional electricity generation, it is necessary to get new renewable sources which would be economically and ecologically profitable in the long-term. Along with wind and ...solar energy, tides, waves etc. it is worth noting that geothermal energy could be in use as well, especially when enhanced geothermal systems are used. Enhanced geothermal systems are artificially made reservoirs while injecting a fluid to make fractures and energy extraction. Some techno-economic issues arise when these enhanced systems are implemented at the particular site (technical, economic, environmental, legal and social impact) and integrated into the heat and electricity grid. This paper gives a short overview of these issues that should be accounted for in the long-term techno-economic modelling. This overview is the first step, necessary for the implementation of specific parameters that will be used later for in-depth techno-economic analysis of enhanced geothermal systems long-term performance.
U ovom radu je prikazan primjer računalne simulacije hibridnog električnog vozila u dva različita režima vožnje. Ovaj primjer pokazuje mnogostruko područje rada simuliranog hibridnog električnog ...vozila. Hibridno električno vozilo je kombiniranog tipa, slično kao u automobilima Toyota Prius. Vozilo ima dvije vrste pogonske snage: elektromotor i motor SUI, u svrhu povećanja stupnja djelovanja pogonskog sklopa i smanjenja zagađenja zraka. Hibridno električno vozilo udružuje prednosti elektromotornog pogona (nema zagađenja i velika raspoloživa snaga pri malim brzinama) i prednosti motora SUI (visoke dinamičke performance i malo zagađenje pri velikim brzinama). Pri simulaciji hibridnog električnog vozila korišten je SimPowerSystems™ i SimDriveline™ (Matlab 11).
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