Quantitative Analyses of Morphological Variation of Cross-Sectional Tracheids of Hinoki (Chamaecyparis obtusa Endl.) Near Knot by Image Processing

Holzforschung ◽  
2002 ◽  
Vol 56 (3) ◽  
pp. 239-243
Author(s):  
J. Liu ◽  
X. M. Diao ◽  
T. Furuno
Keyword(s):  
Aspect Ratio ◽  
Narrow Range ◽  
Ring Width ◽  
Chamaecyparis Obtusa ◽  
Wall Thickening ◽  
Equivalent Diameter ◽  
Cross Sectional ◽  
Annual Ring Width ◽  
Circularity Index ◽  
Quantitative Analyses

Summary Eight transverse sections of hinoki (Chamaecyparis obtusa Endl.) were analyzed along the grain near a knot by circularity index (CI), aspect ratio and equivalent diameter. The specimens were divided into two groups, one above and one below the knot, and their distances from the knot were 0 mm (the nearest), 12 mm, 24 mm, and 36 mm, respectively. Another sample was also selected from knot-free wood for reference along the same grain. A gradual decrease in the aspect ratio of tracheids demonstrated that both boundaries and lumina tended to have small differences in length and width as they approached the knot along the grain. CIs of lumina nearest to the knot indicated astonishingly high values with a narrow range from hexagon to ellipse, compared with the others ranging from rectangle, via hexagon, to ellipse. In other words, lumina showed a tendency to become round near the knot. In addition, the equivalent diameters of lumina tended to decrease when approaching the knot, implying that cell wall thickening of tracheids occur near the knot. It should be noted that the above variations in tracheids accompanied changes in grain orientation and annual ring width, especially the sharp transformation nearest to the knot.

Growth, wood chemistry, and fibre length of Norway spruce in a long-term nutrient optimization experiment

2009 ◽  
Vol 39 (2) ◽  
pp. 410-419 ◽  
Author(s):  
Seija Kaakinen ◽  
Riikka Piispanen ◽  
Satu Lehto ◽  
Johanna Metsometsä ◽  
Urban Nilsson ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Nitrogen Concentration ◽  
Fibre Length ◽  
Ring Width ◽  
Southern Sweden ◽  
Wood Chemistry ◽  
Cross Sectional ◽  
Annual Ring Width ◽  
Lignin Concentration

The study was performed as part of a nutrient optimization experiment at Asa in southern Sweden. The experiment was established 1987, in a Norway spruce ( Picea abies (L.) Karst.) stand planted in 1975. In the nutrient optimization treatment (IL), all essential macro- and micronutrients were supplied, with irrigation water, every second day during the growing season. In October 2003, nine trees were harvested on both untreated control and IL plots. The IL treatment increased annual ring width during the first years of the experiment by ca. 30% and cumulative cross-sectional area 1.5-fold by the end of the experiment. Tracheid length was, however, not affected by the IL treatment. The nitrogen concentration of wood increased and starch concentration decreased as an effect of the IL treatment, suggesting that carbon was allocated to growth rather than storage. The IL treatment increased lignin concentration of wood by 3.4%. Chemical composition varied at different heights along the stem, but with no apparent trend.

scholarly journals Pinch-off of non-axisymmetric vortex rings

2014 ◽  
Vol 740 ◽  
pp. 61-96 ◽  
Author(s):  
Clara O’Farrell ◽  
John O. Dabiri
Keyword(s):  
Aspect Ratio ◽  
Vortex Rings ◽  
Equivalent Diameter ◽  
Local Curvature ◽  
Cross Sectional ◽  
Piston Cylinder ◽  
Circular Arcs ◽  
Axisymmetric Vortex ◽  
Formation Number ◽  
Nozzle Geometries

AbstractThe formation and pinch-off of non-axisymmetric vortex rings is considered experimentally. Vortex rings are generated using a non-circular piston–cylinder arrangement, and the resulting velocity fields are measured using digital particle image velocimetry. Three different nozzle geometries are considered: an elliptical nozzle with an aspect ratio of two, an elliptical nozzle with an aspect ratio of four and an oval nozzle constructed from tangent circular arcs. The formation of vortices from the three nozzles is analysed by means of the vorticity and circulation, as well as by investigation of the Lagrangian coherent structures in the flow. The results indicate that, in all three nozzles, the maximum circulation the vortex can attain is determined by the equivalent diameter of the nozzle: the diameter of a circular nozzle of identical cross-sectional area. In addition, the time at which the vortex rings pinch off is found to be constant along the nozzle contours, and independent of relative variations in the local curvature. A formation number for this class of vortex rings is defined based on the equivalent diameter of the nozzle, and the formation number for vortex rings of the three geometries considered is found to lie in the range of 3–4. The implications of the relative shape and local curvature independence of the formation number on the study and modelling of naturally occurring vortex rings such as those that appear in biological flows is discussed.

IMPACT OF AIR POLLUTION ON RING WIDTH AND TRACHEID DIMENSIONS IN ABIES RELIGIOSA IN THE MEXICO CITY BASIN

IAWA Journal ◽  
2004 ◽  
Vol 25 (2) ◽  
pp. 205-215 ◽  
Author(s):  
Sergio Bernal-Salazar ◽  
Teresa Terrazas ◽  
Dionisio Alvarado
Keyword(s):  
Air Pollution ◽  
Mexico City ◽  
Annual Ring ◽  
Ring Width ◽  
Leaf Damage ◽  
Tree Age ◽  
Wall Thickening ◽  
Annual Ring Width ◽  
Old Trees ◽  
Abies Religiosa

Annual ring width and characteristics of latewood tracheids were characterized for the past 100 years for old trees of Abies religiosa growing in the Desierto de Los Leones within the air-polluted Mexico City basin. Sampled trees had lost nearly 50% of their branches and leaves. Radial variation in most measured characteristics followed typical trends for maturation until the 1970s, when trees were about 70 years old. From that decade onward, there was a continued reduction in annual ring width as well as a reduction in cell wall thickening and tracheid length, but an increase in lumen diameter. These xylem modifications started before the first visual symptoms of leaf damage were detected. We suggest that changes in annual ring width and tracheid size are caused by air pollution rather than by tree age.

Gender determination of caucasoid hair using image analysis

1993 ◽  
Vol 51 ◽  
pp. 216-217
Author(s):  
T.B. Ball ◽  
W.M. Hess
Keyword(s):  
Image Analysis ◽  
Cross Sections ◽  
Scalp Hair ◽  
The Body ◽  
Equivalent Diameter ◽  
Cross Sectional ◽  
Hair Samples ◽  
Length Width ◽  
Morphological Differences

It has been demonstrated that cross sections of bundles of hair can be effectively studied using image analysis. These studies can help to elucidate morphological differences of hair from one region of the body to another. The purpose of the present investigation was to use image analysis to determine whether morphological differences could be demonstrated between male and female human Caucasian terminal scalp hair.Hair samples were taken from the back of the head from 18 caucasoid males and 13 caucasoid females (Figs. 1-2). Bundles of 50 hairs were processed for cross-sectional examination and then analyzed using Prism Image Analysis software on a Macintosh llci computer. Twenty morphological parameters of size and shape were evaluated for each hair cross-section. The size parameters evaluated were area, convex area, perimeter, convex perimeter, length, breadth, fiber length, width, equivalent diameter, and inscribed radius. The shape parameters considered were formfactor, roundness, convexity, solidity, compactness, aspect ratio, elongation, curl, and fractal dimension.

Modification of MnS inclusion by tellurium in 38MnVS6 micro-alloyed steel

2020 ◽  
Vol 117 (6) ◽  
pp. 615
Author(s):  
Ping Shen ◽  
Lei Zhou ◽  
Qiankun Yang ◽  
Zhiqi Zeng ◽  
Kenan Ai ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Aspect Ratio ◽  
Strong Influence ◽  
Experimental Results ◽  
Alloyed Steel ◽  
Equivalent Diameter ◽  
Small Aspect Ratio ◽  
Steel Quality ◽  
Eds Analysis ◽  
Micro Alloyed Steel

In 38MnVS6 steel, the morphology of sulfide inclusion has a strong influence on the fatigue life and machinability of the steel. In most cases, the MnS inclusions show strip morphology after rolling, which significantly affects the steel quality. Usually, the MnS inclusion with a spherical morphology is the best morphology for the steel quality. In the present work, tellurium was applied to 38MnVS6 micro-alloyed steel to control the MnS inclusion. Trace tellurium was added into 38MnVS6 steel and the effect of Te on the morphology, composition, size and distribution of MnS inclusions were investigated. Experimental results show that with the increase of Te content, the equivalent diameter and the aspect ratio of inclusion decrease strikingly, and the number of inclusions with small aspect ratio increases. The inclusions are dissociated and spherized. The SEM-EDS analysis indicates that the trace Te mainly dissolves in MnS inclusion. Once the MnS is saturated with Te, MnTe starts to generate and wraps MnS. The critical Te/S value for the formation of MnTe in the 38MnV6 steel is determined to be approximately 0.075. With the increase of Te/S ratio, the aspect ratio of MnS inclusion decreases and gradually reaches a constant level. The Te/S value in the 38MnVS6 steel corresponding to the change of aspect ratio from decreasing to constant ranges from 0.096 to 0.255. This is most likely to be caused by the saturation of Te in the MnS inclusion. After adding Te in the steel, rod-like MnS inclusion is modified to small inclusion and the smaller the MnS inclusion, the lower the aspect ratio.

Application of Image Analysis System for Study of Activated Sludge Flocs

1986 ◽  
Vol 21 (1) ◽  
pp. 130-140 ◽  
Author(s):  
Da-hong Li ◽  
J. J. Ganczarczyk
Keyword(s):  
Image Analysis ◽  
Activated Sludge ◽  
Statistical Processing ◽  
Equivalent Diameter ◽  
Image Analysis System ◽  
Sectional Area ◽  
Cross Sectional ◽  
Computerized Image Analysis ◽  
Sludge Flocs ◽  
Analysis System

Abstract The computerized image analysis system has been successfully used for determination and statistical processing of the following geometric characteristics of activated sludge flocs: longest dimension, breadth, equivalent diameter, cross-sectional area, perimeter, elongation, and circularity. These parameters could be effectively and precisely determined by the system applied. In addition, the studied method, as compared to direct microscope observation and photography floc-sizing methods, was found to be more accurate, less time-consuming, and less dependent on the investigators.

Cambial activity and ray cell abundance in Acer saccharum

1977 ◽  
Vol 55 (20) ◽  
pp. 2559-2564 ◽  
Author(s):  
R. A. Gregory
Keyword(s):  
Growth Rate ◽  
Acer Saccharum ◽  
Unit Area ◽  
Ring Width ◽  
Cambial Activity ◽  
Relative Volume ◽  
Annual Ring Width ◽  
Ray Cells ◽  
Fusiform Initials ◽  
Ray Cell

The ratio of ray and ray cell initials to fusiform initials of the vascular cambium relative to radial growth rate as reflected in the secondary xylem was studied in stems of Acer saccharum Marsh. Ray initials increased in size as they aged, slowly when growth rate was low, rapidly when it was high, but there was little fluctuation in the number of rays per unit of tangential area; as the cambium increased in circumference, the older, larger rays diverged and new small rays arose in intervening areas, thus maintaining a uniform unit area population independent of growth rate. However, since ray size increased rapidly when growth rate was high, the unit area population of ray cells rose abruptly with accelerating growth rate: the relative volume of xylem ray tissue rose from 8.6 to 12.7% of the total xylem volume when annual ring width increased from 1 to 7 mm. When fast growth was not maintained, the unit area population of ray cells declined slowly as the large rays diverged.

Numerical Simulation of Flow and Heat Transfer in Rectangular Channel With Different Aspect Ratios

2016 ◽  
Author(s):  
Liu Wenhua ◽  
Mo Yang ◽  
Li Ling ◽  
Qiao Liang ◽  
Yuwen Zhang
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Aspect Ratio ◽  
Characteristic Length ◽  
Rectangular Channel ◽  
Equivalent Diameter ◽  
Correction Coefficient ◽  
Corner Region ◽  
Flow And Heat Transfer ◽  
Aspect Ratios

Turbulent flow and heat transfer in rectangular channel has an important significance in engineering. Conventional approach to caculate Nusselt number of rectangular channel approximately is to take the equivalent diameter as the characteristic length and use the classic circular channel turbulent heat transfer coefficient correlations. However, under these conditions, the caculation error of Nusselt number can reach to 14% and thus this approach can not substantially describe the variation of Nusselt number of rectangular cross-sections with different aspect ratios. Therefore, caculation by using equivalent diameter as the characteristic length in classic experiment formula needs to be corrected. Seven groups of rectangular channel models with different aspect ratios have been studied numerically in this paper. By using standard turbulence model, the flow and heat transfer law of air with varing properties has been studied in 4 different sets of conditions in Reynolds number. The simulation and experimental results are in good agreement. The simulation results show that with the increase of aspect ratio, the cross-sectional average Nusselt number increased, Nusselt number of circumferential wall distributed more evenly and the difference between the infinite plate channel and square channel went up to 25%. The effects of corner region and long\short sides on heat transfer have also been investigated in this paper. Results show that in rectangular channel, heat transfer in corner region is significantly weaker than it in other region. With the increase of aspect ratio, effect on the long side of heat transfer of the short side is gradually reduced, and then eventually eliminates completely in the infinite flat place. Based on the studies above, correction coefficient for rectangular channels with different aspect ratios has been proposed in this paper and the accuracy of the correction coefficient has been varified by numerical simulations. This can reflect the variation of Nusselt number under different aspect ratios more effectively and thus has current significance for project to calculate Nusselt number of heat transfer in rectangular channel.

scholarly journals Microcrystal alignment in drawn fiber over sub-meter to kilometer length scales

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Laurel Tauzer ◽  
Ann Mescher
Keyword(s):  
Aspect Ratio ◽  
Composite Fiber ◽  
Polymer Surfaces ◽  
Crystal Length ◽  
Cross Sectional ◽  
Length Scales ◽  
Grapeseed Oil ◽  
The Mean ◽  
Width Reduction ◽  
Uniform Reduction

AbstractThis paper describes a method for aligning stiff, high-aspect-ratio microcrystals over macro-length scales using a polymer fiber drawing process. A composite preform was constructed with an interfacial, liquid shell layer of grapeseed oil suspending ytterbium-doped potassium lutetium fluoride microcrystals (30% Yb:K2LuF5, KLF) between adjacent cylindrical surfaces of acrylic (polymethyl methacrylate, PMMA). The mean length of synthesized KLF microcrystals was 67 microns, and the mean aspect ratio, equivalent to crystal length divided by diameter, was eight. The acrylic-host preform was drawn into fiber, resulting in uniform reduction of all cross-sectional dimensions by a factor of approximately 20 in the final fiber. A corresponding width reduction of the interstitial liquid-filled gap, containing microcrystals between the polymer surfaces, constrains the microcrystals and causes alignment of the crystal long axes parallel to the axis of the drawn composite fiber. Alignment was best for clearly separated microcrystals and improved even further with the longest lengths, or highest aspect-ratio microcrystals.

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