Current efficiency in the chlorate cell process

A mathematical model has been set up for current efficiency in a chlorate cell acting as an ideal electrochemical tubular reactor with a linear increase in hypochlorite concentration from the entrance to the exit. Good agreement was found between the results on current efficiency experimentally obtained under simulated industrial chlorate production conditions and the theoretical values provided by the mathematical model. © 2014 SCS. All rights reserved

Average shape of fluctuations for subdiffusive walks

We study the average shape of fluctuations for subdiffusive processes, i.e., processes with uncorrelated increments but where the waiting time distribution has a broad power-law tail. This shape is obtained analytically by means of a fractional diffusion approach. We find that, in contrast with processes where the waiting time between increments has finite variance, the fluctuation shape is no longer a semicircle: it tends to adopt a table-like form as the subdiffusive character of the process increases. The theoretical predictions are compared with numerical simulation results.Comment: 4 pages, 6 figures. Accepted for publication Phys. Rev. E (Replaced for the latest version, in press.) Section II rewritte

Polarographic determination of cadmium in biological material

Opisana je polarografska metoda za direktno određivanje kadmijuma u mokraći i krvi. Kadmijum se u mokraći kvantitativno taloži kalcium hloridom u slabo kiseloj sredini. Talog se odvaja centrifugovanjem, Organske materije u talogu mineralizuju se perhlornom kiselinom. Uzorak krvi delimično se mineralizuje azotnom kiselinom, gvožđe prevede u hlorid i ekstrahuje etiletrom zajedno sa masnim materijama. Potpuna mineralizacija vrši se sumpornom i perhlornom kiselinom. Mineralizovani ostatak rastvori se u 1 M NaCI i kadmijum odredi polarografski.A polarographic method for direct determination of cadmium in urine and blood is described. In urine cadmium is quantitatively precipitated by calcium chloride in a weakly acid medium. The precipitate is separated by the procedure of centrifugation. The content of organic matter in the precipitate is mineralized by perchloric acid. A blood sample is partly mineralized by nitric acid iron is transformed into chloride and extracted by means of ethyl ether together with the fat matter. Complete mineralization can be done with sulphuric and perchloric acid. The mineralized residue is dissolved in 1 M NaCl and cadmium is determined by polarography

Nonuniversal scaling behavior of Barkhausen noise

We simulate Barkhausen avalanches on fractal clusters in a two-dimensional diluted Ising ferromagnet with an effective Gaussian random field. We vary the concentration of defect sites $c$ and find a scaling region for moderate disorder, where the distribution of avalanche sizes has the form $D(s,c,L) = s^{-(1+\tau (c))}{\cal{D}}(sL^{-D_s(c)})$. The exponents $\tau (c)$ for size and $\alpha (c)$ for length distribution, and the fractal dimension of avalanches $D_s(c)$ satisfy the scaling relation $D_s(c)\tau (c) =\alpha (c)$. For fixed disorder the exponents vary with driving rate in agreement with experiments on amorphous Si-Fe alloys.Comment: 5 pages, Latex, 4 PostScript figures include

Reliability and validity of organizational factors measurement in risk management of process industry equipment

In recent decades, process safety control and process safety risk assessment have become very attractive topics. The way control is carried out, using tools such as HAZOP, FMEA, FTA, and similar is not sufficient to adequately prevent or control accidents with serious consequences in the process industry. The need to analyze the causes of the causes themselves, with special emphasis on the impact of organizational factors has arisen. This research results in the development of an original, reliable, and valid measuring instrument for assessing organizational factors important for risk assessment methodologies in working with pressure equipment. The initial instrument was designed based on the previous research and then checked by statistical analysis, using the KaiserMeyerto-Olkin test, exploratory factor, and reliability analysis. The proposed instrument has reduced 71 to 48 dimensions, describing 10 organizational factors important for risk management of pressure equipment. Providing a valid and reliable measurement instrument is essential for a proactive approach, which enables managers employed in the organization to mitigate the risks of pressure equipment operation, and prevent accidents. The proposal of further research is the application of confirmatory factor analysis or/and structural equation modeling on data collected

Characterization of glycidyl methacrylate based magnetic nanocomposites

Magnetic and non-magnetic macroporous crosslinked copolymers of glycidyl methacrylate and trimethylolpropane trimethacrylate were prepared by suspension copolymerization and functionalized with diethylenetriamine. The samples were characterized by mercury porosimetry, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy analysis (FTIR-ATR), thermogravimetric analysis (TGA), X-ray diffractometry (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM) and SQUID magnetometry. The FTIR-ATR analysis of synthesized magnetic nanocomposites confirmed the presence of magnetite and successful aminofunctionalization. Non-functionalized and amino-functionalized nanocomposites exhibited superparamagnetic behavior at 300 K, with a saturation magnetization of 5.0 emu/g and 2.9 emu/g, respectively. TEM analysis of the magnetic nanocomposite has shown that magnetic nanoparticles were homogeneously dispersed in the polymer matrix. It was demonstrated that incorporation of magnetic nanoparticles enhanced the thermal stability of the magnetic nanocomposite in comparison to the initial non-magnetic macroporous copolymer

Vitex agnus-castus L.: Essential oil increases human erythrocyte membrane fluidity

Fluidnost membrane eritrocita uslovljava njihove reološke karakteristike, svojevrsne dinamičke kvalitete, izmenjene u hipertenziji i aterosklerozi. Rizik od navedenih i drugih kardiovaskularnih oboljenja se kod žena povećava sa starenjem. Tegobe koje prate menopauzu se obično ublažavaju supstitucionom hormonskom terapijom, koja može povećati rizik od pojave malignih oboljenja. Esencijalno ulje biljke Vitex agnus-castus L. sadrži različita organska jedinjenja (monoterpene, seskviterpene i terpenoide) i sve češće se koristi kao alternativno terapijsko sredstvo za simptome menopauze. Navedene komponente esencijalnog ulja mogu se ugraditi u ćelijske membrane i menjati njihovu fluidnost. Cilj studije bio je da se utvrde efekti esencijalnog ulja biljke Vitex agnus-castus na fluidnost membrane eritrocita po njenoj du bini. Korišćena je spektroskopija elektronske paramagnetne rezonance i masnokiselinske spinske probe (5-doksil stearinska i 12-doksil stearinska kiselina), čiji spektri za vise od fluidnosti membrane. Nakon tretmana eritrocita esencijalnim uljem biljke Vitex agnus-castus utvrđeno je značajno (p=0,029) i reverzibilno povećanje fluidnosti njihove membrane u dubljim, hidrofobnim regionima, dok u površinskim, hidrofilnim regionima eritrocitne membrane nisu utvrđene značajne promene (p>0,05). Ovi rezultati ukazuju na povećanje fluidnosti eritrocitne membrane nakon tretmana esencijalnim uljem biljke Vitex agnus-castus, što može biti koristan efekat pri tretmanu pacijentkinja sa hipertenzijom i drugim kardiovaskularnim oboljenjima u menopauzi.Erythrocyte membrane fluidity is related to their rheologic behavior, the dynamic quality of erythrocytes, which is tempted in hypertension and atherosclerosis. An increased risk of these and other cardiovascular diseases occurs in ageing women. Menopause-related conditions are often treated with hormone replacement therapy that may increase the risk of malignancies. Vitex agnus-castus L. essential oil contains various organic compounds (monoterpenes, sesquiterpenes and terpenoids), and is increasingly used as an alternative therapy for menopausal symptoms. These components of the oil may be incorporated into cell membranes, thereby changing the membrane fluidity. The aim of this study was to determine the effects of Vitex agnuscastus essential oil on human erythrocyte membrane fluidity at graded depths. We used Electron Paramagnetic Resonance spectroscopy and fatty acid spin probes (5-doxyl stearic acid and 12-doxyl stearic acid), whose spectra depend on membrane fluidity. After treatment with Vitex agnus-castus essential oil the erythrocytes had a significant (p=0.029) and reversible increase in membrane fluidity in the deeper hydrophobic membrane regions, with no change (p>0.05) in fluidity near the membrane's hydrophilic surface. These results document increased fluidity of the human erythrocyte membrane by Vitex agnus-castus essential oil, and this action may be useful in patients with menopause-related hypertension and other cardiovascular conditions

Novel risk management integrated model implementation: comparison between manufacturing and service companies

Till now a framework to define a common and unified standard model for integrated risk management systems, which is suitable to be used in all contingency factors settings, has not been found. For this reason, as the main objective of applying the standards of management systems in the organizations is to determine the risk that affects the ability of the organization to achieve its goals and desired results in addition to organizing and coordinating all operations and the optimal use of resources, the purpose is to develop an integrated risk management model for standardized management systems with growing trends such as ISO 9001:2015, ISO 14001:2015, ISO/IEC 27001:2013, ISO 45001:2018 and ISO 22000:2018 with the aim to allow organizations to manage their operations and risks appearing in a manner that reduces the use of available resources and improves the overall performance. Novel risk management integrated model in standardized management systems has three levels – correspondence, coordination and integration and putting in place a clear and structured approach to control of organizational risk. Proposed model has been checked empirically to survey contextual independence of proposed model using Mann-Whitney U*test and it has been proved that the model is context free and applicable to companies from different sectors – both in production and service companies

Avalanches in complex spin networks

We investigate the magnetization reversal processes on classes of complex spin networks with antiferromagnetic interaction along the network links. With slow field ramping the hysteresis loop and avalanches of spin flips occur due to topological inhomogeneity of the network, even without any disorder of the magnetic interaction [B. Tadic, et al., Phys. Rev. Lett. 94 (2005) 137204]. Here we study in detail properties of the magnetization avalanches, hysteresis curves and density of domain walls and show how they can be related to the structural inhomogeneity of the network. The probability distribution of the avalanche size, N_s(s), displays the power-law behaviour for small s, i.e. N_s(s)\propto s^{-\alpha}. For the scale-free networks, grown with preferential attachment, \alpha increases with the connectivity parameter M from 1.38 for M=1 (trees) to 1.52 for M=25. For the exponential networks, \alpha is close to 1.0 in the whole range of M.Comment: 16 pages, 10 figures in 29 eps file