scholarly journals DETERMINATION OF GRAIN MOTION MODE ON A VIBRATORY SURFACE

Author(s):  
F.A. Kipriyanov ◽  
◽  
Yu.A. Plotnikova ◽  

he use of vibration transport in agricultural production plays a very significant part. Vibratory conveyors have the variety of advantages over traditional transporting ma-chines such as auger and belt type conveyors used at agri-cultural enterprises for transporting mainly loose and granular materials. A rather low wear coefficient of trans-porting body itself - a conveying trough of a vibration-transporting machine may be referred to the advantages, besides, in some constructions of vibration-transporting machines the amount of friction couples is reduced to a minimum. In the design of constructions of vibration-transporting machines a question arises about the determi-nation of motion mode of particles of the transporting mate-rial. Thus, the detection of a predominant component of motion will allow forecasting the wear rate of a transporting surface and the possibility of enlarging the field of techno-logical use of vibration-transporting machines. During the research process for the determination of motion mode of grain material the shape of which was close to spheroid and ellipsoid, the method of mathematical modeling was applied. The system of differential equations of second order was compiled and solved. In the equations the influ-ence of vibration of a transporting surface on the motion of an elliptically shaped body was taken into account. To solve the system the classical method - Runge-Kutta method of the fourth order was used. The program devel-oped in programming language Python allowed identifying the motion mode of the bodies of spheroidal and ellipsoidal shapes on a vibrating surface. As the result, it was deter-mined that the motion of a body of a spheroidal shape on a vibrating surface was possible due to rolling, and the mo-tion of a body of an ellipsoidal shape was achieved be-cause of its sliding on the surface, what follows from wan-ing rotating movements. The suggested method for the determination of motion mode of a body on a vibrating sur-face is rather flexible and may be applied in calculation for larger bodies in comparison with grain seeds.

Author(s):  
L. J. Yang

Wear rates obtained from different investigators could vary significantly due to lack of a standard test method. A test methodology is therefore proposed in this paper to enable the steady-state wear rate to be determined more accurately, consistently, and efficiently. The wear test will be divided into four stages: (i) to conduct the transient wear test; (ii) to predict the steady-state wear coefficient with the required sliding distance based on the transient wear data by using Yang’s second wear coefficient equation; (iii) to conduct confirmation runs to obtain the measured steady-state wear coefficient value; and (iv) to convert the steady-state wear coefficient value into a steady-state wear rate. The proposed methodology is supported by wear data obtained previously on aluminium based matrix composite materials. It is capable of giving more accurate steady-state wear coefficient and wear rate values, as well as saving a lot of testing time and labour, by reducing the number of trial runs required to achieve the steady-state wear condition.


2017 ◽  
Vol 7 (3) ◽  
pp. 201-210
Author(s):  
Игорь Казаков ◽  
Igor' Kazakov ◽  
Владимир Казаков ◽  
Vladimir Kazakov

The cultivation of seedlings in forest tree nurseries for reforestation and afforestation is an important task of forestry. For sowing seeds of coniferous species in forest nurseries seeder with coil sowing machines are used, which do not provide the desired uniformity of seeding and damage seeds when sowing. Pin sowing machines allow you to eliminate these drawbacks, so research process is interested for forestry. As a result of the research of the process of sowing seeds of conifers by sowing machines with pin metering apparatus, formulas for determination of its angular velocity and rotational speed of the drive of furrow making roller. Formulas to determine seeding rate are proposed, taking into account constructive parameters of seeding machine and size of pins. It is noted that the increase in height and width of pins and also fill factor and number of rows of pins leads to the increase in standards; and increase in gear ratio of the actuator causes its decrease. Uneven supply of seed increases with increased size of pins, so thickness of pins is recommended to be minimum one, taking into account its sufficient strength. Conducted analytical research of the process of work of pin sowing unit enabled to obtain the necessary expressions for calculating structural and technological parameters of the forest sowing machine for sowing seeds of coniferous species in forest nurseries.


2020 ◽  
Vol 12 (1) ◽  
pp. 12-35
Author(s):  
Piotr Jedynak ◽  
Sylwia Bąk

AbstractObjective: The purpose of this text is to identify approaches to defining and subsequently reviewing the definitions of uncertainty and risk as interdisciplinary terms which are of key importance in modern management.Methodology: The work is theoretical. The main method used in the research process was the analysis of scientific literature. A one-dimensional logical classification method was also used, in order to categorize approaches to defining uncertainty and risk, satisfying the exhaustive and mutually exclusive criteria in the selection of categories of approaches.Findings: The main results of the work are: 1) identification of approaches to defining uncertainty and risk, 2) interdisciplinary review of definitions of uncertainty and risk indicating the criteria to distinguish between the two, and 3) determination of the meaning of the terms uncertainty and risk in modern management.Value Added: Considering the approaches to defining uncertainty and risk taken from many fields and disciplines of science, this text is a compendium of theoretical knowledge for the proper understanding and meaning of these concepts in management.Recommendations: The research findings can have implications for both management theory as well as the practice of organization management.


2007 ◽  
Vol 4 (4) ◽  
pp. 571-582
Author(s):  
Baghdad Science Journal

This research work aims to the determination of molybdenum (VI) ion via the formation of peroxy molybdenum compounds which has red-brown colour with absorbance wave length at 455nm for the system of ammonia solution-hydrogen peroxide-molybdenum (VI) using a completely newly developed microphotometer based on the ON-Line measurement. Variation of responses expressed in millivolt. A correlation coefficient of 0.9925 for the range of 2.5-150 ?g.ml-1 with percentage linearity of 98.50%. A detection limit of 0.25 ?g.ml-1 was obtained. All physical and chemical variable were optimized interferences of cation and anion were studied classical method of measurement were done and compared well with newly on-line measurements. Application for the use of developed method on alloy samples, using standard addition method and agreed quite wall.


Author(s):  
Tornados P Silaban ◽  
Faiz . Ahyaningsih

ABSTRACTRunge-Kutta method is a numerical method used to find the solution of an equation. This method seeks to obtain a higher degree of precision, and at the same time seeking to avoid the need of higher derivatives by evaluating the function f (x, y) at the selected point in each interval step. In this paper discussed the effect of changes in the value of the parameter (h) to the value of the error in the Runge-Kutta method Order-3. The equation to be discussed is a linear ordinary differential equation of the two levels that have been changed into a system of linear equations. In the research process was not found fixed parameter values to get the minimum error value, because each parameter has a value of error varied for each equation.Keywords: Runge-Kutta, parameters, error.


Separations ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 3 ◽  
Author(s):  
Benigno José Sieira ◽  
Inmaculada Carpinteiro ◽  
Rosario Rodil ◽  
José Benito Quintana ◽  
Rafael Cela

An analytical method based on high-resolution quadrupole–time-of-flight (QToF) mass spectrometry has been developed as an alternative to the classical method, using a low-resolution ion trap (IT) analyzer to reduce interferences in N-nitrosamines determination. Extraction of the targeted compounds was performed by solid-phase extraction (SPE) following the United States Environmental Protection Agency (USEPA) -521 method. First, both electron impact (EI) and positive chemical ionization (PCI) using methane as ionization gas were compared, along with IT and QToF detection. Then, parameters such as limits of detection (LOD) and quantification (LOQ), linearity, and repeatability were assessed. The results showed that the QToF mass analyzer combined with PCI was the best system for the determination of the N-nitrosamines, with instrumental LOD and LOQ in the ranges of 0.2–4 and 0.6–11 ng mL−1, respectively, which translated into method LOD and LOQ in the ranges of 0.2–1.3 and 0.6–3.9 ng L−1, respectively. The analysis of real samples showed the presence of 6 of the N-nitrosamines in influent, effluent, and tap water. N-nitrosodimethylamine (NDMA) was quantified in all the analyzed samples at concentrations between 1 and 27 ng L−1. Moreover, four additional nitrosamines were found in tap and wastewater samples.


Author(s):  
Ali Cetin ◽  
Trond Pytte ◽  
Sveinung Eriksrud

Operation limits for temporary riser system are determined according to some probability of exceedance of a relevant variable. Accordingly, consistent statistical analysis and probability modelling of the data is required. The common industry approach is to rely on the classical narrow-banded Gaussian process assumption when considering time series of variables of interest. Thus, the time series peaks are characterized by means of the Rayleigh distribution and the relevant extreme values are estimated based on this. However, non-linearities present in riser systems may yield non-Gaussian (wide-banded) processes, rendering the classical approach inappropriate. In the present work, an approximate and practical method is presented to address above issue. It is demonstrated that the approximate method is capable of consistently estimating the relevant extreme values, even where the classical method comes short.


Microbiology ◽  
2006 ◽  
Vol 152 (9) ◽  
pp. 2537-2548 ◽  
Author(s):  
Peter Kuhnert ◽  
Bożena M. Korczak

Genome predictions based on selected genes would be a very welcome approach for taxonomic studies, including DNA–DNA similarity, G+C content and representative phylogeny of bacteria. At present, DNA–DNA hybridizations are still considered the gold standard in species descriptions. However, this method is time-consuming and troublesome, and datasets can vary significantly between experiments as well as between laboratories. For the same reasons, full matrix hybridizations are rarely performed, weakening the significance of the results obtained. The authors established a universal sequencing approach for the three genes recN, rpoA and thdF for the Pasteurellaceae, and determined if the sequences could be used for predicting DNA–DNA relatedness within the family. The sequence-based similarity values calculated using a previously published formula proved most useful for species and genus separation, indicating that this method provides better resolution and no experimental variation compared to hybridization. By this method, cross-comparisons within the family over species and genus borders easily become possible. The three genes also serve as an indicator of the genome G+C content of a species. A mean divergence of around 1 % was observed from the classical method, which in itself has poor reproducibility. Finally, the three genes can be used alone or in combination with already-established 16S rRNA, rpoB and infB gene-sequencing strategies in a multisequence-based phylogeny for the family Pasteurellaceae. It is proposed to use the three sequences as a taxonomic tool, replacing DNA–DNA hybridization.


2012 ◽  
Vol 47 (6) ◽  
pp. 571-578 ◽  
Author(s):  
Miroslava Kačániová ◽  
Lukáš Hleba ◽  
Jaroslav Pochop ◽  
Miriam Kádasi-Horáková ◽  
Martina Fikselová ◽  
...  

2020 ◽  
Vol 9 (6) ◽  
pp. 36
Author(s):  
Thidarat Kruatian ◽  
Kritsana Jitmanee

A greener analytical method for determination of iodine number (IN) of oils is presented. As per the AOAC standard method, a large amount of solvent and reagent was used, and long incubation time was required. This research is aimed at using less amount of solvent and reagent, less sample weight, and shorten the analysis time by using the modified titrimetric AOAC standard method. The study showed that by reducing the sample size, the amount of reagent could be decreased to 1.00 mL and the reaction time of 1 min is enough for completion of the reaction. The amount of reagent used was at least 25 times less than that of the classical method. There was no significant difference at 95% confidence level between the results obtained by the proposed method and the standard method, and both results correlated well. The present method can be applied to edible oils commonly found in the market (iodine number range of 6.0 to 130).


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