Development of an Experimental Setup for the Investigation of Grinding of Wood and a Proposal for a Pulsed Loading Technique

1978 ◽  
Vol 100 (2) ◽  
pp. 147-152
Author(s):  
D. Dornfeld ◽  
S. M. Wu
Keyword(s):  
Wood Properties ◽  
Control Device ◽  
Variable Frequency ◽  
Experimental Setup ◽  
Stone Surface ◽  
Laboratory Equipment ◽  
Surface Conditions ◽  
Pulsed Loading ◽  
Series Of Experiments ◽  
Grinding Operations

The study of the fiberizing mechanism in the grinding of wood requires specialized laboratory equipment to allow process alteration and data collection. The design and development of a unique grinding setup and the control device and instrumentation needed for wood grinding research are outlined. A pulsed loading technique for increasing the effectiveness of the fiberizing mechanism is proposed and this technique is tested in a series of experiments conducted with the grinding operations. Significant energy saving and pulp quality improvement for wood ground at 72 F (22.2 C) are achieved using a variable frequency and amplitude load pulsation superimposed over the constant grinding load. The pulsed loading technique can be used as a control device to minimize the effect of grinder input variation such as wood properties or stone surface conditions by altering the process during grinding to optimize the effect of the fiberizing mechanism.

Use of a Pendulum for Passive Structural Vibrations Control: An Experimental Study

1993 ◽  
Author(s):  
A. Ertas ◽  
O. Cuvalci
Keyword(s):  
Experimental Study ◽  
Dynamic Response ◽  
Passive Control ◽  
Control Device ◽  
Structural Vibrations ◽  
Pendulum System ◽  
Series Of Experiments ◽  
Tip Mass

Abstract The dynamic response of a beam-tip mass-pendulum system subjected to sinusoidal excitations is considered. The conditions under which resonant and nonresonant oscillations occur are investigated and discussed. The main objective of this study was to conduct a series of experiments to investigate the autoparametric interaction between the first two modes of the system. The use of a pendulum as a passive control device was experimentally evaluated.

scholarly journals Compact Laser Collimation System for Simultaneous Measurement of Five-Degree-of-Freedom Motion Errors

2020 ◽  
Vol 10 (15) ◽  
pp. 5057
Author(s):  
Chuang Sun ◽  
Sheng Cai ◽  
Yusheng Liu ◽  
Yanfeng Qiao
Keyword(s):  
Simultaneous Measurement ◽  
Measurement Accuracy ◽  
Measurement Data ◽  
Optical Path ◽  
Degree Of Freedom ◽  
Experimental Setup ◽  
Collimation System ◽  
Optical Configuration ◽  
Series Of Experiments ◽  
The Common

A compact laser collimation system is presented for the simultaneous measurement of five-degree-of-freedom motion errors. The optical configuration of the proposed system is designed, and the principle of the measurement of five-degree-of-freedom errors is described in detail. The resolution of the roll and the horizontal straightness is doubled compared with other laser collimation methods. A common optical path compensation method is provided to detect light drift in real time and compensate for straightness and angle errors. An experimental setup is constructed, and a series of experiments are performed to verify the feasibility and stability of the system. Compared with commercial instruments, the pitch and yaw residuals are ± 2.5 ″ and ± 3.5 ″ without correction, and the residuals are ± 1.9 ″ and ± 2.8 ″ after correction, respectively. The comparison deviations of the horizontal straightness and vertical straightness changed from ± 4.8   μ m to ± 2.8 μm and ± 5.9 μm to ± 3.6 μm, respectively. The comparison deviation of the roll is ± 4.3 ″ . The experimental results show that the data of the five-degree-of-freedom measurement system obtained are largely the same as the measurement data of commercial instruments. The common optical path compensation can effectively improve the measurement accuracy of the system.

Use of Variable Frequency Microwave Energy as a Flexible Plasma Tool

1994 ◽  
Vol 347 ◽  
Author(s):  
A. C. Johnson ◽  
R. A. Rudder ◽  
W. A. Lewis ◽  
R. C. Hendry
Keyword(s):  
Plasma Etching ◽  
Excitation Frequency ◽  
Chemical Vapor ◽  
Target Surface ◽  
Microwave Energy ◽  
Chemical Vapor Infiltration ◽  
Process Efficiency ◽  
Variable Frequency ◽  
Series Of Experiments ◽  
Multi Mode

ABSTRACTThis paper reports on the use of frequency as a control parameter in the generation of microwave-excited plasmas for applications such as chemical vapor deposition, chemical vapor infiltration, or plasma etching. By changing the excitation frequency of a plasma in a multi-mode chamber, the locations of the maxima and minima of the power density within the chamber are also changed. This allows localization of the plasma discharge in the precise processing area desired in order to increase the process' efficiency. In a similar fashion, sweeping of the processing frequency during the process cycle can theoretically “scan” the plasma across an arbitrarily-shaped target surface. A series of experiments was conducted to evaluate the flexibility of variable frequency microwave energy as a plasma process tool. The results of these tests are presented.

scholarly journals An Experimental and Numerical Analysis of Puff Hydrodynamics

2004 ◽  
Vol 21 (3) ◽  
pp. 157-166 ◽  
Author(s):  
MS Saidi ◽  
MR Hajaligol ◽  
F Rasouli
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Air Flow ◽  
Experimental Setup ◽  
Gas Viscosity ◽  
Flow Through ◽  
Series Of Experiments ◽  
Burn Rate ◽  
Centerline Temperature

AbstractThe permeability of a tobacco rod in a cigarette increases as it converts into char and ash in the coal. The hot coal introduces a significant resistance to the air flow when air passes through. Through a series of experiments, the cigarette burn line and burn rate, the centerline temperature, and the pressure drop were measured for continuous puffing conditions. The gas viscosity was calculated from the temperature distribution inside the cigarette and applying Sutherland's law. Then, the experimental setup was mathematically modeled from a commercially available CFD (Computational Fluid Dynamics) code and, by matching the numerical and experimental results, the changes in coal and filter permeability during puffing were estimated. The numerical simulation successfully reproduced the results of experiments on the air flow through the coal, ventilation holes and paper wrapper.

Comparison of Different Dna Preservation Methods On Quinqueloculina Spp. (foraminifera, Miliolida)

2018 ◽  
Vol 48 (3) ◽  
pp. 186-192
Author(s):  
Man Lyu ◽  
Yanli Lei ◽  
Tiegang Li
Keyword(s):  
Rose Bengal ◽  
Ethylenediaminetetraacetic Acid ◽  
Experimental Setup ◽  
Air Drying ◽  
Dna Preservation ◽  
Preservation Methods ◽  
Series Of Experiments ◽  
Lysis Buffer ◽  
Edta Ethylenediaminetetraacetic Acid

Abstract We carried out a series of experiments to evaluate the efficiency of preserving DNA from porcelaneous foraminifera (Quinqueloculina spp.) and a second set to assess the effect of Rose Bengal staining on molecular processing. The first experimental setup assessed three methods of DNA preservation (air-drying, freezing with or without seawater, and Guanidine lysis buffer treatment with or without EDTA (Ethylenediaminetetraacetic acid)). Our study produced the following results: 1) there were no significant differences in DNA preservation when samples were air dried across a range of temperatures (20–120°C); samples frozen at −20°C appeared better preserved than at those frozen at –80°C, and freezing without seawater appeared to produce better preservation than with seawater, though differences in freezing treatments were not significant (p > 0.05); samples in Guanidine lysis buffer with EDTA and stored at –20°C were well preserved (p < 0.05); 2) sometimes, DNA was successfully extracted from samples stained with Rose Bengal. We recommend Guanidine lysis buffer with EDTA, stored at –20°C for up to six weeks, as the best protocol for preservation of DNA from porcelaneous foraminifera.

scholarly journals An experimental approach to the fundamental principles of hemodynamics

2005 ◽  
Vol 29 (3) ◽  
pp. 165-171 ◽  
Author(s):  
Francisco Pontiga ◽  
Susana P. Gaytán
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Experimental Approach ◽  
Experimental Setup ◽  
Simple Construction ◽  
Vascular Networks ◽  
Hands On ◽  
Series Of Experiments ◽  
Physical Variables ◽  
The Relationship

An experimental model has been developed to give students hands-on experience with the fundamental laws of hemodynamics. The proposed experimental setup is of simple construction but permits the precise measurements of physical variables involved in the experience. The model consists in a series of experiments where different basic phenomena are quantitatively investigated, such as the pressure drop in a long straight vessel and in an obstructed vessel, the transition from laminar to turbulent flow, the association of vessels in vascular networks, or the generation of a critical stenosis. Through these experiments, students acquire a direct appreciation of the importance of the parameters involved in the relationship between pressure and flow rate, thus facilitating the comprehension of more complex problems in hemodynamics.

scholarly journals DEVELOPMENT OF WOOD GRINDING. 3. FURTHER TESTING OF GRINDING MODELS

2021 ◽  
Vol 55 (7-8) ◽  
pp. 795-797
Author(s):  
BRUNO LÖNNBERG
Keyword(s):  
Energy Balance ◽  
Moisture Content ◽  
Specific Energy ◽  
Energy Requirement ◽  
Wood Properties ◽  
Wood Moisture Content ◽  
Critical Examination ◽  
Stone Surface ◽  
Wood Moisture ◽  
Specific Energy Requirement

"The study is the continuation of a sequence of works devoted to describing the mechanisms occurring during stone grinding of wood. This part was aimed at further testing of pressurised grinding of spruce wood, which was conducted under controlled laboratory conditions. Testing of the developed theoretical model for power ratio (Pc/Pt) versus energy specific production (Ġw/Pt) produced linears for data representing constant wood moisture content. However, the linears showed almost identical results for fresh woods, and also for drier wood, e.g. wood containing saturated fibres and air-dried wood, although one would expect some differences due to the widely varying constant moisture, from 65% to 15% moisture content. Simplification of the model resulted in (cw + X cm) ΔTp-w ≈ Pt / Ġw, and it led to specific linears, when the members as such were correlated between themselves at several constant wood moisture contents. The results were briefly as follows. Increasing wood feed rate – 0.7, 1.0 and 1.3 mm/s – decreased the specific energy requirement, while increased stone surface speed – 20 and 30 m/s – increased it. The left-hand member or the “X-factor” as named in this context, correlated with the right-hand member or the specific energy requirement and resulted in declining linears. The lower the wood moisture content – 65, 58, 44, 28 and 15% – the smaller was the linear declination, and also the difference due to stone surface speed. The application of an energy balance could be useful in searching for a working wood grinding model. Such a model would enable critical examination of wood grinding conditions. Also, it would help understanding the mechanism of various factors, such as grinding parameters, wood properties and stone burr and sharpness. It seems that there are factors that are not known well enough for further development of grinding. Shower water flow and temperature affect the stone surface temperature as known, but their significance for the energy balance or grinding mechanism are not known. Also, the thin film of pulp slurry between the stone surface and the heat activated wood layer is evidently a significant factor that is connected to the local energy transfer. "

scholarly journals Development of an Experimental Setup to Investigate Influences on Component Distortion in Gravity Die Casting and a First Variation of Temperature Control Strategy

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2028
Author(s):  
Nino Wolff ◽  
Tobias Hohlweck ◽  
Uwe Vroomen ◽  
Andreas Bührig-Polaczek ◽  
Christian Hopmann
Keyword(s):  
Die Casting ◽  
Casting Process ◽  
Geometric Constraints ◽  
Experimental Setup ◽  
Alloy Casting ◽  
Component Design ◽  
Methods Of Evaluation ◽  
Series Of Experiments ◽  
Underlying Mechanisms ◽  
A356 Aluminum

Distortion (1), residual stresses and hot cracks can facilitate significant decreases in quality characteristics of casting products. Their reduction by a suitable component design (2) and process control is therefore desirable. In the casting process, these characteristics are assumed as a result of the combination of solidification shrinkage paired with the local self-feeding and the geometric constraints imposed on the component by the mold. In gravity die casting (3) of aluminum (4) with thermally well conducting and rigid metal molds, the control of solidification through a localized adjustment of the heat balance (5) appears to be a suitable approach to minimize these effects. The development of an experimental setup for the assessment of the interdependencies of the alloy, casting geometry and cooling are described in this work. A first series of experiments with A356 aluminum alloy and the introduction to the different methods of evaluation are presented. Furthermore, an approach to improve the understanding of the underlying mechanisms is outlined.

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