Mathematical description of the flatness of polished glass as a function of production line operating conditions

1994 ◽  
Vol 51 (3-4) ◽  
pp. 113-116
Author(s):  
R. I. Makarov
Keyword(s):  
Mathematical Description ◽  
Production Line ◽  
Polished Glass ◽  
Operating Conditions

scholarly journals Mathematical Model of Pressure Formation Process along the Helix Channel Length of Screw Grinder

2020 ◽  
Author(s):  
Valery Pelenko ◽  
Ilkhom Usmanov ◽  
Vyacheslav Pokholchenko ◽  
Irina Smirnova
Keyword(s):  
Energy Consumption ◽  
Mathematical Description ◽  
Analytical Description ◽  
High Energy ◽  
Channel Length ◽  
Operating Conditions ◽  
Technical Equipment ◽  
Mining Equipment ◽  
Technological Parameters ◽  
Total Energy Consumption

The improvement of the technical equipment effectiveness is currently becoming particularly important. This applies not only to large and high-energy-intensive machines, but also to household appliances, the total energy consumption of which often exceeds the energy consumption of the overall equipment. These types of devices include, in particular, grinding and cutting equipment. The mathematical description of the processes carried out on this equipment is generalized and can be extended to a wider class of machines, including waste processing and mining equipment. The technological parameters, the design of screw grinders, and the processes of movement, deformation, extrusion and cutting carried out in them are characterized by a significant number of factors affecting the energy intensity. The main ones are the geometric parameters of the screw, machine’s body, cross knife, grinding plate’s thickness, the number and diameter of holes in it, as well as the product’s physical-mechanical characteristics and operating conditions. The most important for the mathematical description are the zones and processes where the main share of the consumed power is spent. The complexity of their analytical description is due to a simplified consideration of either individual technological zones of grinders’ existing designs, or the use of unreasonable simplifications.

scholarly journals A transmittance-based methodology for damage detection under uncertainty: An application to a set of composite beams with manufacturing variability subject to impact damage and varying operating conditions

2018 ◽  
Vol 18 (1) ◽  
pp. 318-333 ◽  
Author(s):  
Aggelos G Poulimenos ◽  
John S Sakellariou
Keyword(s):  
Damage Detection ◽  
Production Line ◽  
Composite Structures ◽  
Impact Damage ◽  
Parametric Representation ◽  
Composite Beams ◽  
Operating Conditions ◽  
Ratio Test ◽  
Detection Characteristic ◽  
Testing Procedures

Oftentimes, the complexity in manufacturing composite materials leads to corresponding structures which although they may have the same design specifications they are not identical. Thus, composite parts manufactured in the same production line present differences in their dynamics which combined with additional uncertainties due to different operating conditions may lead to the complete concealment of effects caused by small, incipient, damages making their detection highly challenging. This damage detection problem in nominally identical composite structures is pursued in this study through a novel data-based response-only methodology that is founded on the autoregressive with exogenous (ARX) excitation parametric representation of the transmittance function between vibration measurements at two different locations on the structure. This is a statistical time series methodology within which two schemes are formulated. In the first, a single-reference transmittance model representing the healthy structure is employed, while multiple transmittance models from a sample of available healthy structures are used in the second. The model residual signal constitutes for both schemes the damage detection characteristic quantity that is used in appropriate hypothesis testing procedures with the likelihood ratio test. The methodology is experimentally assessed via damage detection for a population of composite beams which are manufactured in the same production line representing the half of the tail of a twin-boom unmanned aerial vehicle. The damage detection results demonstrate the superiority of the multiple transmittance models based scheme that may effectively detect damages under significant manufacturing variability and varying boundary conditions.

Automatic control of operating conditions in the annealing lehr of a thermally polished glass line

1997 ◽  
Vol 54 (7-8) ◽  
pp. 199-201
Author(s):  
V. I. Kondrashov ◽  
Yu. N. Pentkov ◽  
L. G. Kopchekchi ◽  
F. B. Novikov
Keyword(s):  
Automatic Control ◽  
Polished Glass ◽  
Operating Conditions

In-Situ Coal Gasification: Model Calculations and Laboratory Experiments

1978 ◽  
Vol 18 (02) ◽  
pp. 105-116 ◽  
Author(s):  
C.B. Thorsness ◽  
R.B. Rozsa
Keyword(s):  
Thermal Wave ◽  
Mathematical Description ◽  
Laboratory Experiments ◽  
Coal Gasification ◽  
Packed Bed ◽  
Operating Conditions ◽  
Permeable Zone ◽  
Gasification Process ◽  
Product Gas

Abstract One concept for in-situ coal gasification involves fracturing thick, deep, coal seams using chemical explosives. The resultant high-permeability zone then would be ignited and reacted with a steam/ oxygen mixture to produce medium-Btu gas suitable for upgrading to pipeline quality in a surface plant. This paper discusses the calculational modeling and supporting laboratory experiments relating to the gasification process. The primary aim of this preliminary work is to predict and correlate reaction preliminary work is to predict and correlate reaction and thermal-front propagation rates and product gas composition as a function of bed properties and process operating conditions. process operating conditions. Our initial efforts are restricted to onedimensional, transient Darcy flow in a permeable packed bed. The numerical calculations include a packed bed. The numerical calculations include a detailed description of the reacting system chemistry (13 species) with appropriate reaction rates and over-all heat and mass transport in the system. Comparison of calculated results with experimental data from a packed-bed combustion tube shows good agreement for reaction-zone propagation rates and produced-gas compositions. propagation rates and produced-gas compositions. However, the sensitivity of the calculations to other reaction-rate and transport-coefficient models should be investigated. Introduction In-situ coal gasification has received renewed interest recently. It offers four potential advantages over conventional mining and subsequent surface processing of coal: (1) the product gas may be processing of coal:the product gas may be cheaper because of lower capital investment requirements;environmental damage is likely to be lower;hazards to miners are avoided; andit may make possible the exploitation of coal resources too deeply buried for economical recovery by conventional strip or deep mining operations. The Lawrence Livermore Laboratory (LLL) packed-bed concept for coal gasification was packed-bed concept for coal gasification was originated in 1972. Major program funding by the U.S. ERDA began in 1974. The LLL concept is designed to recover medium-Btu gas from the thick, deeply buried, subbituminous coal deposits prevalent in the western U.S. After upgrading in a prevalent in the western U.S. After upgrading in a surface facility the product gas would have sufficiently high energy density to make pipeline distribution attractive economically. The packed-bed concept calls for creating a permeable zone of coal by detonating chemical permeable zone of coal by detonating chemical explosives in an array of drilled boreholes. The top of the resulting permeable zone is supplied and a steam/oxygen reactant mixture is supplied. The oxidation reactions produce a high-temperature zone that propagates through the bed as a slowmoving thermal wave. The thermal wave first dries the coal downstream from the reaction zone and then pyrolyzes (devolatilizes) it, forming a char. The char undergoes further reactions with the steam present. The major products of the over-all process include H2, CO, CH4, and CO2 as gases, process include H2, CO, CH4, and CO2 as gases, and water and tar as liquids. Mathematical modeling and laboratory experimentation have been carried out to increase understanding of the important parameters of the in-situ gasification process. The purpose of this paper is to present a mathematical description of paper is to present a mathematical description of the gasification process, together with results obtained from calculations and laboratory-scale gasification reactor experiments. The long-range goal of our modeling effort is to acquire the ability to predict resource recovery for a variety of different field geometries and operating conditions. This is a multidimensional, multiphase flow problem. The preliminary model described here is a transient, one-dimensional model of the gasification process in a packed bed. The primary reason for its development is to provide a framework in which to test the importance of accurate specification of the large number of physical and chemical processes involved in gasification. This will be accomplished primarily through comparisons with carefully controlled experiments performed in the 1.6-m reactor. SPEJ P. 105

scholarly journals Mathematical description of the groundwater pumping process during the design of the automatic drainage system

2020 ◽  
Vol 222 ◽  
pp. 01006
Author(s):  
I. Shtykova ◽  
T. Shinkevich ◽  
G. Ybytayeva
Keyword(s):  
Mathematical Model ◽  
Groundwater Level ◽  
Mathematical Description ◽  
Drainage System ◽  
Operating Conditions ◽  
Construction Technology ◽  
Pumping Station ◽  
Control Value ◽  
Groundwater Supply ◽  
The Cost

The main structure of any building is the foundation. It takes on itself and transfers all its load to the ground. When choosing the type of foundation, the decisive factor is considered to be the characteristics of the soil, the depth of freezing, as well as the level of groundwater, which gives the developer a lot of problems. The foundation under high groundwater level greatly affects the strength and load-bearing capacity of the building and requires a big investment. The groundwater level will be the fundamental criteriawhen calculating the cost of development, construction technology, durability of the structure and operating conditions of the building. The process of designing such systems is significantly complicated by multidimensionality, non-stationarity, as well as the non-linear nature of control objects. When developing an automatic drainage system, it is necessary to build a high-quality mathematical model of the pumping station. The article discusses the process of building an automatic system of groundwater regulation in a drainage tank based on a given control value and disturbing effect. The mathematical description is developed for the control circuit “water level - speed of the drainage pump” with the main disturbing effect - a change in the groundwater supply Mathematical model of the pumping station is implemented using a virtual simulation program - ViSSim.Based on the obtained model, an automatic drainage system can be developed to prevent flooding of the foundation with ground water during the construction of buildings and structures.

Cathodoluminescence of Catalyst Crystallites

1982 ◽  
Vol 40 ◽  
pp. 664-665
Author(s):  
E.D. Boyes ◽  
P.L. Gai ◽  
D.B. Darby ◽  
C. Warwick
Keyword(s):  
Defect Density ◽  
Chemical Properties ◽  
Operating Conditions ◽  
Semiconductor Materials ◽  
Environmental Cell ◽  
High Resolution Structure ◽  
Commercially Important ◽  
Crystallographic Defects ◽  
Resolution Structure

The extended crystallographic defects introduced into some oxide catalysts under operating conditions may be a consequence and accommodation of the changes produced by the catalytic activity, rather than always being the origin of the reactivity. Operation without such defects has been established for the commercially important tellurium molybdate system. in addition it is clear that the point defect density and the electronic structure can both have a significant influence on the chemical properties and hence on the effectiveness (activity and selectivity) of the material as a catalyst. SEM/probe techniques more commonly applied to semiconductor materials, have been investigated to supplement the information obtained from in-situ environmental cell HVEM, ultra-high resolution structure imaging and more conventional AEM and EPMA chemical microanalysis.

Comparison of Deterministic and Linear Cosine Spatial Filtering of Transmission Electron Micrographs

1972 ◽  
Vol 30 ◽  
pp. 596-597
Author(s):  
David A. Ansley
Keyword(s):  
Spherical Aberration ◽  
Focal Length ◽  
Chromatic Aberration ◽  
Spatial Filter ◽  
Operating Conditions ◽  
Objective Lens ◽  
List Type ◽  
Spatial Filters ◽  
Transmission Electron ◽  
Wide Range

The coherence of the electron flux of a transmission electron microscope (TEM) limits the direct application of deconvolution techniques which have been used successfully on unmanned spacecraft programs. The theory assumes noncoherent illumination. Deconvolution of a TEM micrograph will, therefore, in general produce spurious detail rather than improved resolution.A primary goal of our research is to study the performance of several types of linear spatial filters as a function of specimen contrast, phase, and coherence. We have, therefore, developed a one-dimensional analysis and plotting program to simulate a wide 'range of operating conditions of the TEM, including adjustment of the:(1) Specimen amplitude, phase, and separation(2) Illumination wavelength, half-angle, and tilt(3) Objective lens focal length and aperture width(4) Spherical aberration, defocus, and chromatic aberration focus shift(5) Detector gamma, additive, and multiplicative noise constants(6) Type of spatial filter: linear cosine, linear sine, or deterministic

Slow-scan CCD cameras and low-dose High-Resolution Electron Microscopy: Direct and quantitative

1994 ◽  
Vol 52 ◽  
pp. 412-413
Author(s):  
M. Pan
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Structural Damage ◽  
Low Dose ◽  
Dynamic Range ◽  
High Resolution Electron Microscopy ◽  
Operating Conditions ◽  
Digital Data ◽  
Ccd Cameras ◽  
Resolution Electron

It has been known for many years that materials such as zeolites, polymers, and biological specimens have crystalline structures that are vulnerable to electron beam irradiation. This radiation damage severely restrains the use of high resolution electron microscopy (HREM). As a result, structural characterization of these materials using HREM techniques becomes difficult and challenging. The emergence of slow-scan CCD cameras in recent years has made it possible to record high resolution (∽2Å) structural images with low beam intensity before any apparent structural damage occurs. Among the many ideal properties of slow-scan CCD cameras, the low readout noise and digital recording allow for low-dose HREM to be carried out in an efficient and quantitative way. For example, the image quality (or resolution) can be readily evaluated on-line at the microscope and this information can then be used to optimize the operating conditions, thus ensuring that high quality images are recorded. Since slow-scan CCD cameras output (undistorted) digital data within the large dynamic range (103-104), they are ideal for quantitative electron diffraction and microscopy.

Simulation and Contrast Analysis of tem Images of Cracks

1990 ◽  
Vol 48 (1) ◽  
pp. 578-579
Author(s):  
D. Goyal ◽  
A. H. King
Keyword(s):  
Displacement Vector ◽  
Crack Tip ◽  
Perfect Crystal ◽  
Operating Conditions ◽  
Displacement Fields ◽  
Fringe Contrast ◽  
Orthogonal Geometry ◽  
Moire Fringe ◽  
Moiré Fringe

TEM images of cracks have been found to give rise to a moiré fringe type of contrast. It is apparent that the moire fringe contrast is observed because of the presence of a fault in a perfect crystal, and is characteristic of the fault geometry and the diffracting conditions in the TEM. Various studies have reported that the moire fringe contrast observed due to the presence of a crack in an otherwise perfect crystal is distinctive of the mode of crack. This paper describes a technique to study the geometry and mode of the cracks by comparing the images they produce in the TEM because of the effect that their displacement fields have on the diffraction of electrons by the crystal (containing a crack) with the corresponding theoretical images. In order to formulate a means of matching experimental images with theoretical ones, displacement fields of dislocations present (if any) in the vicinity of the crack are not considered, only the effect of the displacement field of the crack is considered.The theoretical images are obtained using a computer program based on the two beam approximation of the dynamical theory of diffraction contrast for an imperfect crystal. The procedures for the determination of the various parameters involved in these computations have been well documented. There are three basic modes of crack. Preliminary studies were carried out considering the simplest form of crack geometries, i. e., mode I, II, III and the mixed modes, with orthogonal crack geometries. It was found that the contrast obtained from each mode is very distinct. The effect of variation of operating conditions such as diffracting vector (), the deviation parameter (ω), the electron beam direction () and the displacement vector were studied. It has been found that any small change in the above parameters can result in a drastic change in the contrast. The most important parameter for the matching of the theoretical and the experimental images was found to be the determination of the geometry of the crack under consideration. In order to be able to simulate the crack image shown in Figure 1, the crack geometry was modified from a orthogonal geometry to one with a crack tip inclined to the original crack front. The variation in the crack tip direction resulted in the variation of the displacement vector also. Figure 1 is a cross-sectional micrograph of a silicon wafer with a chromium film on top, showing a crack in the silicon.

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