Anchoring the Potential Energy Surfaces of Homogenous and Heterogenous Dimers of Formaldehyde and Thiofomaldehyde

This work characterizes five stationary points of the formaldehyde dimer, (CH2O)2, two of which are minima, seven newly-identified stationary points of the formaldehyde/thioformaldehyde (mixed) dimer, CH2O/CH2S, four of which are minima, and five newly-identified stationary points of the thioformaldehyde dimer, (CH2S)2 , three of which are minima. Full geometry optimizations and corresponding harmonic vibrational frequencies were performed on CH2O and CH2S as well as each of the dimer configurations (Figures 3-5). The computations were carried out with second order Møller-Plesset perturbation theory (MP2), with the heavy-auc-cc-pVTZ (haTZ) basis set. Additionally, thirteen density functional theory methods were employed: B3LYP, B3LYP-D3, B3LYP-D3(BJ), TPSS, TPSS-D3, TPSS-D3(BJ), APF, APF-D, M06-2X, M06-2X-D3, N12SX, MN12SX, and VSXC, in conjunction with the 6-311+G(2df,2pd) basis set. Six of these functionals are dispersion corrected with either the original D3 damping function (DFT-D3) or the Becke-Johnson damping function [DFT-D3(BJ)]. Binding energies were computed via the supermolecular approach. Single-point energies were also computed for all optimized structures using explicitly correlated MP2-F12 and CCSD(T)-F12 methods with the haTZ basis set. The (CH2O)2 and CH2O/CH2S global minimum are the same at the MP2, MP2-F12, and CCSD(T) levels of theory. However, MP2 methods overbind (CH2S)2 by as much as 1.1 kcal mol-1, effectively altering the energetic ordering of the (CH2S)2 minima relative to the CCSD(T)-F12 energies

Analysis of Surface Runoff

A mathematical model of surface runoff is presented which is of use in building a model of erosion processes. The method used for deriving the conceptual model of surface runoff is based on the mathematical expression of the basic laws of movement of water -- the equation of continuity and the equation of motion. Both equations form a system of nonlinear partial differential equations with two unknown functions expressing the depth and velocity of the movement of water along the slope, in dependence on their location on the slope, and time. The input variables of the model are the intensity and direction of the impinging raindrops, the intensity of infiltration and the physical characteristics of the slope (gradient, length and properties of soil surface). Extensive laboratory experiments have been carried out to determine the functional dependence of tangential stress on the depth and rate of runoff from different types of soil surfaces. Further, the conceptual model of surface runoff has been simplified to a kinematic one by using a simple relation between depth and rate of surface runoff instead of the equation of motion. Two empirical parameters of this relation have been determined by using data from the above mentioned laboratory experiments during calibration of the kinematic model. The kinematic model is recommended because of its simplicity with regard to simulation of the surface runoff formation from individual slopes within the watershed. The model is a multipurpose one. It may be used either for hydrological purposes (simulation of surface runoff characteristics) or for soil conservation purposes. The model outputs are surface characteristics (depth, velocity, rate). It is possible by comparing the surface runoff velocity with the critical nonscouring velocity for given field conditions to determine the critical slope length which is the basis for planning efficient soil conservation measures

Zaštita okoliša Genetski modificirani organizmi i Hrvatska

Predstavljamo članak temeljen na predavanju dr. sc. Mirele Holy “GMO i Hrvatska” održanom 29. svibnja 2013. u sklopu tribine “Zaštita okoliša u Hrvatskoj u procesu pristupanja Europskoj uniji (EU)”, koju organiziraju Hrvatsko društvo kemijskih inženjera i tehnologa (HDKI) i časopis Kemija u industriji (KUI) Vjeročka Vojvodić (urednik

Gambaran Histopatologik Mukosa Laring Tikus Wistar Yang Dipapar Asap Rokok, Obat Nyamuk Bakar, Dan Kendaraan Bermotor

: Air polution is a condition where the air is contaminated with chemicals, particles/matters and other biological substances such as cigarette smoke, mosquito coil smoke, and exhaust gas. Cigarette smoke, mosquito coil smoke and exhaust gas contain substances that can cause inflammation, hyperresponsivity, obstruction, and metaplasia of the respiratory tract. This study aimed to compare the exposure effect of cigarette smoke, mosquito coil smoke, and exhaust gas on the histopathological features of Wistar rat larynx. This was an experimental laboratory study. Subjects were 20 rats divided into 4 groups; Group I, the negative control group, and 3 treatment groups (Group II, III, and IV). Group II was exposed by cigarette smoke, group III was exposed by mosquito coil smoke, and group IV was exposed by exhaust gas. Subjects were put in a modified exposure cage in according with the treatment groups and were exposed for 2 hours per day for 30 days. The results showed that inflammatory cells were found the most in group 4, meanwhile in group II were the least. Metaplasia occured the most in group II, menwhile group III and IV had similar results. In general, group IV showed the worst pathological reaction, followed by group III and group II. Conclusion: Histopathological feature of larynx of wistar rat exposed by exhaust gas showed the worst histopathological changes, followed by mosquito coil smoke exposure group and cigarette smoke group