Technological parameters of the ammonolysis of waste 1,2-dichloropropane

The ammonolysis of waste 1,2-dichloropropane (DCP) using liquid ammonia has been investigated. The influence of temperature, molar ratio of NH3/1,2-dichloropropane and reaction time was examined. The highest yield of the synthesis was achieved at a temperature of 140 degrees C, for the reaction time of 3 h and the molar ratio of NH3/1,2-dichloropropane as 20:1. Under these conditions the degree of 1,2-dichloropropane conversion amounted to 97.1 mol% and the selectivity of transformation to 1,2-diaminopropane (DAP) in relation to consumed 1,2-dichloropropane was 25.3 mol%, whereas in relation to consumed ammonia 17.9 mol%. The remaining 1,2-dichloropropane reacts to form polypropyleneamines.     

Epoxidation of methallyl chloride with t-butyl hydroperoxide

By applying a statistical method of experiment planning the optimum conditions of methallyl chloride epoxidation with t-butyl hydroperoxide have been determined. The influences of the temperature, molar ratio of the methallyl chloride to t-butyl hydroperoxide, catalyst concentration and reaction time on the selectivity of the synthesis of methylglycerol epichlorohydrine in relation to reacted t-butyl hydroperoxide have been examined.     

Determination of frictional properties of geotextiles

The influence of some test conditions on the measured frictional properties of geotextiles is discussed. Conclusions and suggestions are presented, based on research on some non-woven and woven geotextiles in a small (10 cm × 10 cm) and large (25 cm × 40 cm) direct shearboxes as well as from pull-out tests. Specifications for testing frictional properties of textiles, which have been published in Poland, are also briefly presented.     

A new integral identity for potential polygonal domain problems described by parametric linear functions

The paper presents a modification of the classical integral identity for two-dimensional potential boundary value problems with a linear segments boundary. The modification consists of describing integral contours in the integral identity by means of parametric linear functions. As a result of the modification, it was possible to obtain a new integral identity, which included the geometry of the boundary in its subinterval functions. The identity can be used for finding solutions in polygonal domains under the condition that the solutions previously obtained on the boundary are arrived at by the new parametric integral equation system. The proposed method makes it possible to obtain solutions of domain problems with no need for the discretization of the boundary geometry. The effectiveness of the method is illustrated by three testing examples.     

Structural and surface properties of TiO2 thin films doped with neodymium deposited by reactive magnetron sputtering

Thin films were deposited using modified, high energy magnetron sputtering method from Ti-Nd mosaic targets. The amount of neodymium dopant incorporated into two sets of thin films was estimated to be 0.8 and 8.5 at.%, by means of energy dispersive spectroscopy. On the basis of x-ray diffraction method, the type of crystalline structure and crystallites size were evaluated directly after the deposition process and after additional post-process annealing at 800 °C temperature. The influence of annealing on the surface properties was evaluated with the aid of atomic force microscopy. Uniformity of the dopant distribution in titanium dioxide matrix was examined with the aid of secondary ion mass spectroscopy. Additionally, using atomic force microscope, diversification and roughness of the surface was determined. Chemical bonds energy at the surface of TiO₂:Nd thin films was investigated by x-ray photoelectron spectroscopy method. Wettability measurements were performed to determine contact angles, critical surface tensions and surface free energy of prepared coatings. On the basis of performed investigations it was found, that both factors, the amount of neodymium dopant and the post-process annealing, fundamentally influenced the physicochemical properties of prepared thin films.     

Restriction techniques for the unit-commitment problem with total procurement costs

Many discrete optimization problems may be solved much easier, if the solution space can be restricted in a convenient way. For a given specific problem, the restriction techniques can be helpful if an available optimization solver, perceived as a black box, is capable of solving quickly only reduced subproblems of a limited size. For the family of hard unit-commitment problems we investigate a hierarchical search algorithm, which is based on decomposition of the problem into two subproblems. The upper-level subproblem is a relatively small decision “kernel” of the problem that can be solved approximately by a search algorithm. We define an appropriate restricted decision space for this subproblem. The lower-level subproblem is an appropriate restriction of the original problem that can be solved efficiently by a dedicated solver. Our approach was analyzed on a set of historical data from the Polish electrical balancing market and the best known solutions were improved by the average of about 2–5%.     

The Influence of Reaction Parameters on the Epoxidation of Rapeseed Oil with Peracetic Acid

The influence of reaction parameters on the epoxidation of rapeseed oil (RO) with peracetic acid obtained in situ from the reaction between 30 wt% hydrogen peroxide and glacial acetic acid (AA) has been studied. The course of the reaction was measured by changes of the iodine number (IN) and epoxy number (EN), used to estimate the degree of rapeseed oil conversion, yield, and the selectivity of transformation to epoxidized rapeseed oil in relation to the total amount of oil undergoing the transformation. The optimal conditions of epoxidation are as follows: temperature 60 °C, molar ratio of hydrogen peroxide to rapeseed oil 9.5:1 mol/mol, molar ratio of acetic acid to rapeseed oil 1.12:1 mol/mol, stirring speed 500 rpm, and reaction time of 4 h. Under these conditions the epoxy number is equal to 0.157 mol/100 g RO and iodine number reaches low values of 0.123 mol/100 g RO. The selectivity of transformation to epoxidized RO calculated from EN and IN is 82.2%, conversion of hydrogen peroxide is 100%, conversion of RO calculated from IN is 60.8%, and yield of RO calculated from EN is 50%.     

Adsorption dynamics of chlorinated hydrocarbons from multi-component aqueous solution onto activated carbon

The results and a numerical simulation of studies on dynamics of the adsorption from seven-component aqueous solution of light chlorinated hydrocarbons on activated carbon have been presented. Aqueous solution of 1,2-dichloroethane (12DCE), 1,1,2,2-tetrachloroethane (S-TET), chloroform (CHCl(3)), carbon tetrachloride (CCl(4)), 1,1-dichloroethene (VDC), perchloroethene (PER) and 1,1,2-trichloroethene (TRI) was used. Concentrations of chlorohydrocarbons were similar as in wastewater from vinyl chloride plant. A cell model that incorporates the diffusion through a laminar layer of liquid around a particle was used to describe the experimental results. The applied calculation methods, which take kinetics into account, allows to well describe a phenomenon of dynamic adsorption. Mean relative deviations between the experimental and calculated values amounted 17%. The breakthrough curves become steeper along with an increase of the bed height. A consistency of the experimental results with those calculated indicates for a negligible contribution of the axial diffusion on the dynamic adsorption process of light chlorinated hydrocarbons from aqueous solution under the hydrodynamic conditions corresponding to the Reynolds number equal to 1.3. Determined optimal bed height for waste linear flow rate-15 cm/min is in the range 80-120 cm.     

A separation of the boundary geometry from the boundary functions in PIES for 3D problems modeled by the Navier–Lamé equation

In this paper, we present a modification of the Somigliana identity for the 3D Navier–Lamé equation in order to analytically include in its mathematical formalism the boundary represented by Coons and Bézier parametric surface patches. As a result, the equations called the parametric integral equation system (PIES) with integrated boundary shape are obtained. The PIES formulation is independent from the boundary shape representation and it is always, for any shape, defined in the parametric domain and not on the physical boundary as in the traditional boundary integral equations (BIE). This feature is also helpful during numerical solving of PIES, as from a formal point of view, a separation between the approximation of the boundary and the boundary functions is obtained. In this paper, the generalized Chebyshev series are used to approximate the boundary functions. Numerical examples demonstrate the effectiveness of the presented strategy for boundary representation and indicate the high accuracy of the obtained results.     

Detection of the liquid — liquid demixing by differential scanning calorimetry

Polymer Bulletin - From theoretical considerations it is concluded that the demixing temperatures of moderately concentrated polymer solutions should manifest themselves in a change of the slope of...