JUSTIFICATION THE HOPPER OUTLET FORM, WHICH PROVIDES CONSTANT DISCHARGE OF THE GRAIN

10.12737/3813 ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. 79-83
Author(s):  
Савенков ◽  
Dmitriy Savenkov
Keyword(s):  
Friction Force ◽  
Experimental Research ◽  
Flow Rate ◽  
Industrial Development ◽  
Air Flow ◽  
External Friction ◽  
Constant Flow ◽  
Friction Forces ◽  
Frictional Forces ◽  
Side Walls

The uniformity of air flow in the aspirating channels largely depends on constant supply of grain across the channel. However, most of the feeding aspirators do not provide a constant flow of particulate mater. That’s why one of the areas of industrial development of new technological operations is their preliminary theoretical and experimental research. The uniformity expiration of grain from the hopper to the outlet side occurs through the action of frictional forces. The friction forces are divided into internal and external friction, opposing the grain movement. External friction force, provided by the walls of the hopper, reduce the exhaust velocity of bulk near the walls. Thus, the extensional discharge of the bulk is more in the central parts of the outlet, than in its outer parts. Reducing the extensional discharge in the extreme zones is associated with a decrease in the flow rate of these zones. So that to ensure a constant grain unloading from the hopper, it is proposed to change the outlet profile, enhancing the area of outlet in the areas of its contact with the edges of the side walls. It is shown, that the area of the secondary part depends on the angle of the bottom hopper and the height of the outlet. The results of the data can be used to optimize the geometry of the hopper.

scholarly journals Friction Forces during Sliding of Various Brackets for Malaligned Teeth: An In Vitro Study

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Vito Crincoli ◽  
Letizia Perillo ◽  
Maria Beatrice Di Bisceglie ◽  
Antonio Balsamo ◽  
Vitaliano Serpico ◽  
...  
Keyword(s):  
Friction Force ◽  
In Vitro Study ◽  
Friction Forces ◽  
Orthodontic Wire ◽  
Conventional Brackets ◽  
Frictional Forces ◽  
The Right ◽  
Post Hoc ◽  
Sliding Mechanics

Aims. To measure the friction force generated during sliding mechanics with conventional, self-ligating (Damon 3 mx, Smart Clip, and Time 3) and low-friction (Synergy) brackets using different archwire diameters and ligating systems in the presence of apical and buccal malalignments of the canine.Methods. An experimental setup reproducing the right buccal segment of the maxillary arch was designed to measure the friction force generated at the bracket/wire and wire/ligature interfaces of different brackets. A complete factorial plan was drawn up and a three-way analysis of variance (ANOVA) was carried out to investigate whether the following factors affect the values of friction force: (i) degree of malalignment, (ii) diameter of the orthodontic wire, and (iii) bracket/ligature combination. Tukey post hoc test was also conducted to evaluate any statistically significant differences between the bracket/ligature combinations analyzed.Results. ANOVA showed that all the above factors affect the friction force values. The friction force released during sliding mechanics with conventional brackets is about 5-6times higher than that released with the other investigated brackets. A quasilinear increase of the frictional forces was observed for increasing amounts of apical and buccal malalignments.Conclusion. The Synergy bracket with silicone ligature placed around the inner tie-wings appears to yield the best performance.

scholarly journals Peristaltic transport of a two-layered fluid in a catheterized tube

2012 ◽  
Vol 39 (4) ◽  
pp. 291-311
Author(s):  
Amit Medhavi ◽  
U.K. Singh
Keyword(s):  
Pressure Drop ◽  
Linear Relationship ◽  
Layer Thickness ◽  
Friction Force ◽  
Flow Rate ◽  
Tube Wall ◽  
Flow Characteristics ◽  
Tube Size ◽  
Friction Forces ◽  
Catheter Size

The flow of a two-layered Newtonian fluid induced by peristaltic waves in a catheterized tube has been investigated. The expressions for the flow characteristics- the flow rate, the pressure drop and the friction forces at the tube and catheter wall are derived. It is found that the pressure drop increases with the flow rate but decreases with the increasing peripheral layer thickness and a linear relationship between pressure and flow exists. The pressure drop increases with the catheter size (radius) and assumes a high asymptotic magnitude at the catheter size more that the fifty percent of the tube size. The friction forces at the tube and catheter wall posses characteristics similar to that of the pressure drop with respect to any parameter. However, friction force at catheter wall assumes much smaller magnitude than the corresponding value at the tube wall.

IMPROVING OF EFFICIENCY OF BAND-BLOCK BRAKE WORK BY REDUCING OF DYNAMIC AND THERMAL LOADINGS

2018 ◽  
pp. 218-225
Author(s):  
F. V. Kozak ◽  
S. I. Krystopa ◽  
L. I. Krystopa ◽  
Y. M. Arsenych
Keyword(s):  
Experimental Research ◽  
Thermal Loading ◽  
Structural Parameters ◽  
External Friction ◽  
Friction Units ◽  
Frictional Forces

This article is devoted to theoretical and experimental research of loading of new multi-pair friction units of band-block brakes of drilling hoists of drill units in stand conditions.Mathematical dependencies are made to determine frictional forces, efforts of tensions of incident and matching branches of the tape and the brake moments developed by the internal and external friction pairs. On the basis of dynamic and thermal loading of the latter, rational structural parameters of the brake were determined.

scholarly journals RESEARCH ON THE AERODYNAMIC RESISTANCE OF TRICKLE BIOFILTER / LAŠELINIO BIOFILTRO AERODINAMINIO PASIPRIEŠINIMO TYRIMAI

2011 ◽  
Vol 3 (5) ◽  
pp. 64-69 ◽  
Author(s):  
Alvydas Zagorskis ◽  
Renata Spiečiūtė
Keyword(s):  
Surface Area ◽  
Experimental Research ◽  
Flow Rate ◽  
Air Flow ◽  
Aerodynamic Resistance ◽  
Packing Material ◽  
Large Surface Area ◽  
Air Flow Rate ◽  
First Case ◽  
Artificial Origin

A four – section trickle biofilter was constructed for experimental research. The filter was filled with the packing material of artificial origin. The material consists of plastic balls having a large surface area. The dependence of biofilter aerodynamic resistance on supply air flow rate and the number of filter sections was determined. The aerodynamic resistance of the biofilter was measured in two cases. In the first case, the packing material of the filter was dry, whereas in the second case it was wet. The experimental research determined that an increase in the air flow rate from 0.043 m/s to 0.076 m/s causes an increase in biofilter aerodynamic resistance from 30.5 to 62.5 Pa after measuring four layers of dry packing material. In case of wet packing material, biofilter aerodynamic resistance after measuring four layers of plastic balls increases from 42.1 to 90.4 Pa. Santrauka Eksperimentiniams tyrimams atlikti sukonstruotas keturių sekcijų lašelinis biofiltras. Filtras užpildytas dirbtinės kilmės įkrova, sudaryta iš didelį paviršiaus plotą turinčių plastikinių rutuliukų. Naudojant įkrovą, skirtą introdukuotų mikroorganizmų asociacijoms kultivuoti, nustatytos biofiltro aerodinaminio pasipriešinimo priklausomybės nuo tiekiamo oro srauto greičio ir sekcijų skaičiaus. Biofiltro aerodinaminis pasipriešinimas matuotas dviem atvejais: esant sausai ir sudrėkintai įkrovai. Nustatyta, kad didinant tiekiamo oro srauto greitį nuo 0,043 iki 0,076 m/s, įrenginio aerodinaminis pasipriešinimas išmatavus keturis įkrovos sluoksnius padidėja nuo 30,5 iki 62,5 Pa tuo atveju, kai įkrova sausa, ir nuo 42,1 iki 90,4 Pa, – kai įkrova sudrėkinta.

Effect of Atomic-Scale Surface Roughness on Friction

2005 ◽  
Author(s):  
Mark Robbins ◽  
Binquan Luan ◽  
Sangil Hyun ◽  
Judith Harrison ◽  
Noam Bernstein
Keyword(s):  
Friction Force ◽  
Three Dimensional ◽  
Atomic Scale ◽  
Radius Of Curvature ◽  
Affine Scaling ◽  
Elastic Solids ◽  
Friction Forces ◽  
Flat Surfaces ◽  
Frictional Forces ◽  
Atomically Flat

Simulations of friction between clean, atomically flat surfaces indicate that the friction force per unit area decreases to zero with increasing area. In previous work, we showed that the presence of mobile atoms between surfaces suppresses this superlubric behavior. The current paper examines the effect of atomic scale roughness. Both single asperities and random self-affine surfaces are considered in two and three-dimensional geometries. We have also examined the effect of commensurability, and elastic or plastic deformation within the bounding solids. The friction force on single asperities decreases to zero as the contact area and radius of curvature increase, but can still be significant at the scale of scanning probe tips. Introducing mobile atoms leads to friction forces that rise linearly with area in large contacts. Frictional forces on random self-affine surfaces can be quite complex. If self-affine scaling extends down to atomic dimensions, the average contact between elastic solids only contains a few atoms and the friction can be large. Plasticity increases contact dimensions and may lower the friction.

Removal of trichloroethylene and trichloroethane using a novel hollow-fibre gas-permeable membrane

2003 ◽  
Vol 3 (5-6) ◽  
pp. 67-72
Author(s):  
S. Takizawa ◽  
T. Win
Keyword(s):  
Boundary Layer ◽  
Flow Regime ◽  
Removal Efficiency ◽  
Residence Time ◽  
Flow Rate ◽  
Air Flow ◽  
Hollow Fibre ◽  
Permeation Rate ◽  
Permeable Membrane ◽  
Diffusional Boundary Layer

In order to evaluate effects of operational parameters on the removal efficiency of trichloroethylene and 1,1,1-trichloroethene from water, lab-scale experiments were conducted using a novel hollow-fibre gaspermeable membrane system, which has a very thin gas-permeable membrane held between microporous support membranes. The permeation rate of chlorinated hydrocarbons increased at higher temperature and water flow rate. On the other hand, the effects of the operational conditions in the permeate side were complex. When the permeate side was kept at low pressure without sweeping air (pervaporation), the removal efficiency of chlorinated hydrocarbon, as well as water permeation rate, was low probably due to lower level of membrane swelling on the permeate side. But when a very small amount of air was swept on the membrane (air perstripping) under a low pressure, it showed a higher efficiency than in any other conditions. Three factors affecting the permeation rate are: 1) reduction of diffusional boundary layer within the microporous support membrane, 2) air/vapour flow regime and short cutting, and 3) the extent of membrane swelling on the permeate side. A higher air flow, in general, reduces the diffusional boundary layer, but at the same time disrupts the flow regime, causes short cutting, and makes the membrane dryer. Due to these multiple effects on gas permeation, there is an optimum operational condition concerning the vacuum pressure and the air flow rate. Under the optimum operational condition, the residence time within the hollow-fibre membrane to achieve 99% removal of TCE was 5.25 minutes. The log (removal rate) was linearly correlated with the average hydraulic residence time within the membrane, and 1 mg/L of TCE can be reduced to 1 μg/L (99.9% removal).

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