scholarly journals Determination of the pressing parameters of spruce water-resistant plywood

2008 ◽  
Vol 53 (No. 5) ◽  
pp. 231-242 ◽  
Author(s):  
J. Hrázský ◽  
P. Král
Keyword(s):  
Heat Transmission ◽  
Variable Parameters ◽  
Strength Coefficient ◽  
Shearing Strength

The paper summarizes results of operations aimed at determining the pressing parameters of spruce water-resistant plywood and testing the suitability of particular constructions of plywood. Constant and variable parameters were determined. In pressed plywood sheets, the shearing strength of gluing according to EW 100 and the coefficient of compressibility were determined. In pressing, heat transmission through the set of veneers was analyzed and effects of the moisture of veneers on heat transmission were tested. The percentage of resin hardening was also determined. Results were statistically analyzed. The dependence was determined of shearing strength, coefficient of compressibility and heat transmission on changes in pressing parameters. Results of the study consist in the proposal of pressing parameters for particular constructions of plywood.

scholarly journals Use of N, N-diethyl-p-phenylenediamine sulphate for the spectrophotometric determination of some phenolic and amine drugs

2010 ◽  
Vol 60 (2) ◽  
pp. 217-227 ◽  
Author(s):  
Padmarajaiah Nagaraja ◽  
Ashwinee Shrestha ◽  
Anantharaman Shivakumar ◽  
Avinash Gowda
Keyword(s):  
Spectrophotometric Determination ◽  
Correlation Coefficients ◽  
Dosage Forms ◽  
Pharmaceutical Dosage Forms ◽  
Variable Parameters ◽  
Spectrophotometric Methods ◽  
Linear Relationships ◽  
Colored Product ◽  
And Performance

Use ofN, N-diethyl-p-phenylenediamine sulphate for the spectrophotometric determination of some phenolic and amine drugsSpectrophotometric methods are proposed for the determination of drugs containing a phenol group [salbutamol sulphate (SLB), ritodrine hydrochloride (RTD), isoxsuprine hydrochloride (IXP)] and drugs containing an aromatic amine group [dapsone hydrochloride (DAP), sulfamethoxazole (SFM), and sulfadiazine (SFD)] in pharmaceutical dosage forms. The methods are based on coupling ofN, N-diethyl-p-phenylenediamine sulphate with the drugs in the presence of KIO4to give a green colored product (λmaxat 670 nm) and a red colored product (λmaxat 550 nm), respectively. Linear relationships with good correlation coefficients (0.9986-0.9996) were found between absorbance and the corresponding concentration of drugs in the range 1-7, 2-22, 1-17, 1.5-12, 2-25, and 2-21 μg mL-1for SLB, RTD, IXP, DAP, SFM and SFD, respectively. Variable parameters such as temperature, reaction time and concentration of the reactants have been analyzed and optimized. The RSD of intra-day and inter-day studies was in the range of 0.2-1.0 and 0.4-1.0%, respectively. No interference was observed from common pharmaceutical adjuvants. The reliability and performance of the proposed methods was validated statistically; the percentage recovery ranged from 99.5 ± 0.1 to 99.9 ± 0.3%. Limits of detection were 0.14, 0.21, 0.51, 0.44, 0.33 and 0.37 μg mL-1for SLB, RTD, IXP, DAP, SFM, and SFD, respectively.

Numerical Modeling of Heat and Mass Transport with Inner Heat Exchange in Unsaturated Porous Media

2020 ◽  
Vol 27 ◽  
pp. 166-176
Author(s):  
Jozef Kačur ◽  
Patrik Mihala
Keyword(s):  
Mathematical Model ◽  
Porous Media ◽  
Heat Exchange ◽  
Inverse Problems ◽  
Water Transport ◽  
Heat Conductivity ◽  
Unsaturated Porous Media ◽  
Heat Transmission ◽  
Matrix Heat

We are focused to the numerical modelling of heat, contaminant and water transport in unsaturated porous media in 3D. The heat exchange between water and porous media matrix is taken into the account. The determination of heat energy transmission coefficient and matrix heat conductivity is solved by means of inverse problem methods. The mathematical model represents the conservation of heat, contaminant and water mass balance. It is expressed by coupled non-linear system of parabolic-elliptic equations. Mathematical model for water transport in unsaturated porous media is represented by Richard's type equation. Heat transport by water includes water flux, molecular diffusion and dispersion. A successful experiment scenario is suggested to determine the required parameters including heat transmission and matrix heat conductivity coefficients. Additionally we investigate contaminant transport with heat transmission and contaminant adsorption. The obtained experiments support our method suitable for solution of direct and inverse problems. This problem we have discussed previously in 1D model, but preferential streamlines in 1D thin tubes shadow accurate results in determination of required parameters. In our presented setting we consider a cylindrical sample which is suitable in laboratory experiments for inverse problems.

scholarly journals Energy consumption of chipper coupled to a universal wheel skidder in the process of chipping wood

2011 ◽  
Vol 57 (No. 1) ◽  
pp. 34-40 ◽  
Author(s):  
J. Kováč ◽  
J. Krilek ◽  
M. Mikleš
Keyword(s):  
Energy Consumption ◽  
Input Power ◽  
Variable Parameters ◽  
Whole Process ◽  
Revolution Frequency ◽  
Energy Consuming

The chipper for chips is an energy consuming machine. Many factors influence the result of chipping which influence the whole process. The paper deals with the process of wood chipping by a chipper in order to determine its energy consumption. The main purpose was the determination of input power and comparison of revolution frequency on the outlet shaft of a skidder regarding the dimension of the torque depending on variable parameters which characterize the process of wood chipping during the measurement and the analysis of energy consumption of a chipping machine was carried out.

EVALUATION OF SIEVE ANALYSIS METHODS FOR THE DETERMINATION OF FIBER CONTENT IN SAMPLES OF RUBBER POWDER

2012 ◽  
Vol 85 (4) ◽  
pp. 661-668
Author(s):  
Ana María Rodríguez-Alloza ◽  
Juan Gallego-Medina ◽  
José María Bermejo-Muñoz ◽  
Leticia Saiz-Rodríguez
Keyword(s):  
Weight Percent ◽  
Test Methods ◽  
Fiber Content ◽  
Sieve Analysis ◽  
Variable Parameters ◽  
Rubber Powder ◽  
Powder Samples ◽  
Sieve Analyses ◽  
Materials Used

ABSTRACT The objective of this article is to study the validity of the test methods that are currently used to determine the fiber content in samples of rubber powder made from end-of-life tires: CEN/TS 14 243, ASTM D 5603-01, and XP T 47–758. For this purpose, rubber powder samples contaminated with one weight percent (wt%) of fiber were prepared and submitted to sieve analyses, with the weight of the sample and sieving time as the variable parameters. The materials used were rubber powder without fibers and polyester fibers from recycled waste tires, both generated during the shredding of the tires. It has been observed that the procedure of determining fiber content based on sieving and extraction of fabric balls does not manage to recover more than 41.00% of the fibers contained in the samples. This research demonstrates that even with different sample weights and sieving times, is not possible to recover 100% of the fiber with which the rubber sample was contaminated. This seems to indicate that it is necessary to develop a methodology that differs from the current practice of sieving and extracting fabric balls to correctly determine the fiber content in a sample of rubber powder.

scholarly journals Thermographic determination of the sheath heat transmission coefficient in a high density plasma

2013 ◽  
Vol 438 ◽  
pp. S431-S434 ◽  
Author(s):  
M.A. van den Berg ◽  
K. Bystrov ◽  
R. Pasquet ◽  
J.J. Zielinski ◽  
G. De Temmerman
Keyword(s):  
Transmission Coefficient ◽  
High Density ◽  
Heat Transmission ◽  
Density Plasma

Gross Error Elimination and Index Determination of Shearing Strength Parameters in Triaxial Test

2013 ◽  
Vol 353-356 ◽  
pp. 152-158
Author(s):  
Fang Wei
Keyword(s):  
Nonlinear Programming ◽  
Solution Process ◽  
Friction Angle ◽  
Triaxial Tests ◽  
Strength Parameters ◽  
Gross Error ◽  
Error Elimination ◽  
Shearing Strength ◽  
Programming Solution

In order to determine shearing strength parameters of triaxial tests(cohesion and friction angle), nonlinear programming solution was suggested based on “minimum square sum of distance”. After proving that the vertical distances between Mohr circles and the regressed strength line are distributed normally, data with gross error would be excluded; moreover, the only strength line, as well as cohesion and friction angle, could be determined. Combining with Matlab, the solution process became rapid, precise and intuitive. Some examples verified the applicability of suggested method finally.

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