scholarly journals Variability in swelling of spruce (Picea abies [L.] Karst.) wood with the presence of compression wood

2008 ◽  
Vol 53 (No. 6) ◽  
pp. 243-252 ◽  
Author(s):  
V. Gryc ◽  
H. Vavrčík ◽  
P. Horáček
Keyword(s):  
Compression Wood ◽  
Longitudinal Direction ◽  
Tangential Direction ◽  
Transverse Plane ◽  
Opposite Wood ◽  
Sample Tree ◽  
Swelling Coefficient ◽  
Hygroscopic Material ◽  
The Individual ◽  
Shape Changes

Wood is a hygroscopic material that is affected by shape changes. The aim of this study was to analyse the variability of wood swelling in the individual anatomic directions. Wood swelling was examined on a sample tree containing compression wood. With regard to the presence of compression wood, the sample tree was divided into the following three zones: the compression wood zone (CW), the opposite wood zone (OW), and two side wood zones (SWL and SWR). The results show that the wood containing compression wood swells less at the transverse plane (in the radial and tangential direction). Conversely, the swelling of compression wood in the longitudinal direction is higher. The same proportion was established in the swelling coefficient that grew proportionally to the increasing wood density in all anatomic directions. The proportion of compression wood manifested its effects in different ways. Transversely (in the radial and tangential direction) the swelling coefficient decreased proportionally to the increasing percentage of compression wood, longitudinally, however, the opposite was the case.

Autonomy and non-autonomy in Drosophila mesoderm determination and morphogenesis

Development ◽  
1994 ◽  
Vol 120 (4) ◽  
pp. 853-859 ◽  
Author(s):  
M. Leptin ◽  
S. Roth
Keyword(s):  
Cell Shape ◽  
Shape Change ◽  
Developmental Program ◽  
Cell Shape Change ◽  
Ventral Furrow ◽  
Large Numbers ◽  
The Individual ◽  
Mutant Cells ◽  
Transplantation Experiments ◽  
Shape Changes

The mesoderm in Drosophila invaginates by a series of characteristic cell shape changes. Mosaics of wild-type cells in an environment of mutant cells incapable of making mesodermal invaginations show that this morphogenetic behaviour does not require interactions between large numbers of cells but that small patches of cells can invaginate independent of their neighbours' behaviour. While the initiation of cell shape change is locally autonomous, the shapes the cells assume are partly determined by the individual cell's environment. Cytoplasmic transplantation experiments show that areas of cells expressing mesodermal genes ectopically at any position in the egg form an invagination. We propose that ventral furrow formation is the consequence of all prospective mesodermal cells independently following their developmental program. Gene expression at the border of the mesoderm is induced by the apposition of mesodermal and non-mesodermal cells.

Cross-field pitting characteristics of compression, lateral, and opposite wood in the stem wood of Ginkgo biloba and Pinus densiflora

IAWA Journal ◽  
2020 ◽  
Vol 41 (1) ◽  
pp. 48-60
Author(s):  
Byantara Darsan Purusatama ◽  
Nam Hun Kim
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Ginkgo Biloba ◽  
Compression Wood ◽  
Pinus Densiflora ◽  
Reaction Wood ◽  
Stem Wood ◽  
Opposite Wood ◽  
The Cross ◽  
Scanning Electron

Abstract The characteristics of cross-field pitting among compression wood, lateral wood, and opposite wood, in the stem woods of Ginkgo biloba and Pinus densiflora were investigated with optical and scanning electron microscopy. In Ginkgo biloba, compression wood exhibited piceoid pits, while lateral and opposite wood exhibited cupressoid pits. The compression wood of Pinus densiflora exhibited cupressoid pits and piceoid pits, while lateral wood and opposite wood exhibited pinoid and window-like pits in the cross-field. In both species, compression wood yielded the smallest pit number among each part, while opposite wood yielded the greatest pit number per cross-field. Cross-field pitting diameters of compression wood and opposite wood were significantly smaller than lateral wood in Ginkgo biloba, while the cross-field pitting of compression wood was the smallest in Pinus densiflora. Radial tracheid diameter of compression wood was slightly smaller than lateral and opposite wood in Ginkgo biloba and significantly smaller than lateral and opposite wood in Pinus densiflora. In conclusion, the cross-field pitting type, pit number, and cross-field pitting diameter could be used to identify reaction wood in the stem wood of Ginkgo biloba and Pinus densiflora.

Visualization of Individual Growth-Related Craniofacial Changes Based on Cephalometric Landmark Data: A Pilot Study

2002 ◽  
Vol 39 (3) ◽  
pp. 341-352 ◽  
Author(s):  
Christopher J. Lux ◽  
Jens Starke ◽  
Jan Rübel ◽  
Angelika Stellzig ◽  
Gerda Komposch
Keyword(s):  
Dynamic Behavior ◽  
Growth Process ◽  
Shape Change ◽  
Individual Growth ◽  
Craniofacial Skeleton ◽  
Size And Shape ◽  
Lateral Cephalograms ◽  
Landmark Data ◽  
The Individual ◽  
Shape Changes

Objective: An approach based on Euclidean distances between cephalometric landmarks is presented (1) to visualize and localize the individual shape changes of the complex craniofacial skeleton during growth and (2) to depict the individual dynamic behavior of developmental size and shape changes. Patients and Method: Growth-related craniofacial changes were investigated exemplarily for two male orthodontically untreated subjects from the Belfast Growth Study on the basis of lateral cephalograms at 7, 9, 11, 13, and 15 years. The interlandmark distances among seven skeletal cephalometric landmarks served as a database for the study. A modified Karhunen-Loèvedecomposition based on orthogonal modes and time-dependent scalar amplitudes was used to describe the growth process. The individual shape changes of the various craniofacial regions were visualized by allocation of colors to the respective distances, and overdrawn representations were reconstructed by means of multidimensional scaling. Results and Conclusions: This visualization technique allows anatomical regions to be characterized with respect to reduced or strengthened growth, compared with pure size changes. The clinically relevant mechanisms of craniofacial changes are visualized (e.g., shifts in the anteroposterior or vertical dimensions of the jaws in relation to cranial base and structural imbalances during development). In addition, overdrawing the effects of shape change on the skeletal structures gives a more readily comprehensible impression of the growth process. Taking account of the methodical limitations of this approach (e.g., the restrictions concerning the number of landmarks), the clinician may take advantage of this technique in orthodontic or surgical diagnostics to gain additional insight into the individual complex size and shape changes during development along with their dynamic behavior.

Residual-Stress, Material Characterization in P22 HRSG-Pipeline Butt Joint

2020 ◽  
Author(s):  
Ottaviano Grisolia ◽  
Lorenzo Scano ◽  
Francesco Piccini ◽  
Antonietta Lo Conte ◽  
Massimiliano De Agostinis ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Level ◽  
Outer Surface ◽  
High Stress ◽  
Base Material ◽  
Longitudinal Direction ◽  
Tangential Direction ◽  
Butt Joint ◽  
Hole Drilling ◽  
Plane State

Abstract Previous study evaluated residual stress in a circumferential “V”-groove butt joint of a heat-recovery steam generator (HRSG) pipeline; the material was ASTM A-335-Grade P22. Aim had been to check on the influence over creep-relaxation previously found out for a tee made of the same material. The butt joint had been operating for the same period of 200,000 hours, same temperature of 528°C at almost a half pressure (0.46 Kg/mm2 vs. 1.06 Kg/mm2). X-ray diffraction (XRD) technique applied close to the weld highlighted anomalously high stress-level on the outer surface for all four butt-joint samples tested. Residual-stress over 400 MPa observed along the cylinder’s tangential direction was statically not acceptable. On the inner surface where deposited beads may have tempered adjacent base material, measurement via blind hole-drilling (BHD) technique showed a symmetrical plane-state residual-stress of 199 MPa. It was consistent with that observed via XRD on the outer surface in the cylinder’s longitudinal direction. Supposing a case of incomplete post heating planned for the weld may have explained the occurrence of being much higher than 40 MPa, value predicted after 200,000 hours. Similar influence over creep results found out for the tee and the butt joint had validated modeling welding simulation considered for both joints. A comprehensive new series of XRD tests aims now at measuring residual stress across the cylinder’s wall, both inner and outer sides. The shallow layer considered has thickness sufficient for building a map of measurements covering different depths and locations on the surface. The experimental plan includes also BHD tests supporting the XRD ones. Comparison with previous measurements roughly shows stress level increasing similarly across the cylinder’s wall from the inner side on: Average stress values, however, appear lower than previous measurements, showing better compatibility to the analysis results.

Strength and stiffness of the reaction wood in five Eucalyptus species

Holzforschung ◽  
2019 ◽  
Vol 73 (2) ◽  
pp. 219-222
Author(s):  
Bruno Charles Dias Soares ◽  
José Tarcísio Lima ◽  
Selma Lopes Goulart ◽  
Claudineia Olímpia de Assis
Keyword(s):  
Mechanical Behavior ◽  
Tension Wood ◽  
Compression Wood ◽  
Vertical Position ◽  
Eucalyptus Species ◽  
Reaction Wood ◽  
Opposite Wood ◽  
Average Slope ◽  
Strength And Stiffness

AbstractTree stems deviating from the vertical position react by the formation of tension wood (TW) or compression wood (CW), which are called in general as reaction wood (RW), in which the cells are modified chemically and anatomically. The focus of the present work is the mechanical behavior of TW in five 37-year-oldEucalyptusspecies, which were grown on a planting area with an average slope of 28% leading to decentralized pith in the trees, which is an unequivocal indication of the presence of RW. TW and opposite wood (OW) samples were isolated and subjected to a compression-parallel-to-grain test. It was observed that TW is less resistant and less stiff than the OW.

scholarly journals Variability in density of spruce (Picea abies [L.] Karst.) wood with the presence of reaction wood

2008 ◽  
Vol 53 (No. 3) ◽  
pp. 129-137 ◽  
Author(s):  
V. Gryc ◽  
P. Horáček
Keyword(s):  
Picea Abies ◽  
Moisture Content ◽  
Wood Density ◽  
Compression Wood ◽  
Wood Properties ◽  
3D Models ◽  
Reaction Wood ◽  
Stem Height ◽  
Sample Tree

The study was aimed to assess the integral value that determines wood properties − wood density at a moisture content of 0% and 12%. The wood density was researched in a sample tree with the presence of reaction compression wood. The density was determined for individual zones (CW, OW, SWL and SWR). The zone where compression wood (CW) is present has a higher density than the remaining zones. On the basis of the acquired data, 3D models were created for individual zones; they describe the variability of wood density along the stem radius and stem height. The influence of the radius seems to be a statistically highly significant factor. The wood density is significantly higher in samples with the presence of compression wood. When the proportion of compression wood in the sample was 80%, the wood density was 1.5 times higher compared to wood without compression wood.

Effect of abnormal fibres on the mechanical properties of paper made from Norway spruce, Picea abies (L.) Karst.

Holzforschung ◽  
2008 ◽  
Vol 62 (2) ◽  
pp. 149-153 ◽  
Author(s):  
Nasko Terziev ◽  
Geoffrey Daniel ◽  
Ann Marklund
Keyword(s):  
Mechanical Properties ◽  
Picea Abies ◽  
Norway Spruce ◽  
Cell Walls ◽  
Compression Wood ◽  
Morphological Changes ◽  
Mechanical Processing ◽  
Opposite Wood ◽  
Tear Index ◽  
Control Samples

Abstract The aim of the present study was to determine the effect of a variety of abnormal fibres on the mechanical properties of paper made from Norway spruce, Picea abies (L.) Karst. Fibres representing abnormality were obtained from trees treated by irrigation and fertilisation. Moreover, fibres from compression wood and its accompanying opposite wood were isolated. The effect of dislocations on paper quality was studied on four mixtures (20, 40, 60 and 80% fibres with induced dislocations) of untreated/compressed fibres. Two more groups consisting of control untreated samples and samples with 100%-induced dislocations were also included in the test. The mechanical properties of the paper were tested and the results were compared to those of control samples. Abnormal fibres reduced the desired mechanical properties of the final paper concerning tensile strength, modulus of elasticity and tear-tensile index. Irrespective of the type of treatment, all morphological changes introduced in fibre cell walls appear to directly affect changes in the mechanical properties of the paper. Control samples had a tear index of 25 compared to 10 mN m2 g-1 of samples containing 100% dislocations. It is obvious that 20% of dislocations, an amount that is expected to be induced in pulp under mechanical processing and transport, will contribute to a decrease in tear index with an average of 3 mN m2 g-1, i.e., 10% of the total value.

Anatomical Comparison Between Compression Wood and Opposite Wood in a Branch of Korean Pine (Pinus Koraiensis)

IAWA Journal ◽  
1988 ◽  
Vol 9 (3) ◽  
pp. 275-284 ◽  
Author(s):  
Phil Woo Lee ◽  
Young Geun Eom
Keyword(s):  
Compression Wood ◽  
Pinus Koraiensis ◽  
Korean Pine ◽  
Qualitative And Quantitative ◽  
Opposite Wood

Compression wood and opposite wood formed in the branch of Korean pine (Pinus koraiensis S. et Z.) is described and compared in qualitative and quantitative anatomical aspects.

Metatarsal Loading During Gait—A Musculoskeletal Analysis

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Amir A. Al-Munajjed ◽  
Jeffrey E. Bischoff ◽  
Mehul A. Dharia ◽  
Scott Telfer ◽  
James Woodburn ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Longitudinal Direction ◽  
Extensive Study ◽  
Detailed Knowledge ◽  
Dynamic Simulations ◽  
Inverse Dynamic ◽  
Metatarsal Bones ◽  
First Ray ◽  
The Individual ◽  
Joint Loads

Detailed knowledge of the loading conditions within the human body is essential for the development and optimization of treatments for disorders and injuries of the musculoskeletal system. While loads in the major joints of the lower limb have been the subject of extensive study, relatively little is known about the forces applied to the individual bones of the foot. The objective of this study was to use a detailed musculoskeletal model to compute the loads applied to the metatarsal bones during gait across several healthy subjects. Motion-captured gait trials and computed tomography (CT) foot scans from four healthy subjects were used as the inputs to inverse dynamic simulations that allowed the computation of loads at the metatarsal joints. Low loads in the metatarsophalangeal (MTP) joint were predicted before terminal stance, however, increased to an average peak of 1.9 times body weight (BW) before toe-off in the first metatarsal. At the first tarsometatarsal (TMT) joint, loads of up to 1.0 times BW were seen during the early part of stance, reflecting tension in the ligaments and muscles. These loads subsequently increased to an average peak of 3.0 times BW. Loads in the first ray were higher compared to rays 2–5. The joints were primarily loaded in the longitudinal direction of the bone.

scholarly journals Examination of Facial Shape Changes Associated with Cardiovascular Disease Using Geometric Morphometrics

2018 ◽  
Vol 3 (1) ◽  
Keyword(s):  
Cardiovascular Disease ◽  
Cardiovascular Diseases ◽  
Geometric Morphometrics ◽  
Directional Asymmetry ◽  
Facial Morphology ◽  
Geometric Morphometric ◽  
Facial Shape ◽  
Normal Individuals ◽  
The Individual ◽  
Shape Changes

Facial investigations using geometric morphometrics has been used in many studies to affirm that a particular disease can attribute to an individual’s facial morphology. A landmark based geometric morphometric analysis was used in this study to asses if facial shape changes are associated with cardiovascular diseases (CVD) and if facial morphology of the CVD individuals differs from the normal ones. In the Municipality of Cantilan, Surigao del Sur, frontal face images taken from 32 cardiovascular disease patients and 32 normal individuals were examined using forty-one manually positioned landmarks. Result showed that facial morphology of the CVD group differs from non-CVD group. Procrustes ANOVA showed significant values for the individual symmetry and directional asymmetry. The analysis of structure by the Principal Components reveals particular variations and the scatter plot of the residual asymmetry shows distinct differences between CVD and non-CVD. Therefore, cardiovascular diseases contribute to facial shape changes and that development of facial morphology differs between CVD and non-CVD group.

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