Proportion Of Rays Research Articles

Studies on the Anatomical Structure of Fast-Growing <i>Toona ciliate</i>

In this paper, anatomical characters and tissue proportion of fast-growing Toona ciliata samples from Guangzhou was investigated assisted with the light microscope and image analysis system based on the principle of stereology. Qualitative and quantitative data were presented for purposes of identification. Results showed that fast growing T. ciliata was coarse texture with wide growth ring of 3~5cm.The ray proportion was 12.12%-25.56%, the mean value was 17.98%, increasing with time-dependent relevance. The vessel-elements proportion was 6.37%-10.00%, the mean value was 7.40%, increasing then declining and finally increasing. The fiber and other tissue proportion was 67.06%-79.92%, the mean value was 74.62%, declining by year.

Variation in anatomical properties and correlations with wood density and compressive strength in Casuarina equisetifolia growing in Bangladesh

Summary Variation in anatomical properties and relationships with air-dry density and compressive strength were examined in wood of 10-y-old Casuarina equisetifolia. Average vessel diameter increased gradually between sample points 2.5 cm and 7.5 cm from the pith. Vessel frequency decreased between sample points 2.5 cm and 5 cm from the pith and then stabilised. Average fibre diameter decreased gradually from pith to bark, while fibre wall thickness displayed a reverse trend. The proportion of vessels decreased slightly between the 2.5 and 5 cm sample points and then increased again towards the bark. Fibre and cell wall proportions increased from the pith to bark. The proportion of rays was nearly constant along the radius, while the proportion of axial parenchyma decreased somewhat toward the bark. Vessel diameter, fibre wall thickness and the proportions of fibre and cell wall were positively correlated with air-dry density, whereas fibre diameter showed a negative correlation. A significant negative correlation was found between compressive strength and fibre diameter. Strong positive correlations suggest that variation in air-dry density and compressive strength is mainly determined by the proportion of cell wall in transverse sections.

Relationship between the radial variation of ray characteristics and the stages of radial stem increment in Zelkova serrata

We used ten discs from two Zelkova serrata trees - five discs from each tree at sampling heights of 1, 4, 7, 10, and 13 m above the ground - and investigated the radial variation in ray characteristics, i.e., ray area (cross-sectional area of rays on a tangential section), ray density (number of rays/mm2 on a tangential section), and ray proportion (the percentage of the area occupied by rays on a tangential section) and analyzed the pattern of variation with respect to the three stages (early, middle, and late) of radial stem increment as estimated using the Gompertz growth function. A juvenile-mature pattern of variation was observed in ray area and ray density. Ray area increased in the inner part of stem and fluctuated around a certain value in the outer part of the stem, and ray density decreased in the inner part of stem and tended to be constant in the outer part of the stem. The maturation age of ray density was similar to the age at the boundary between the early and the middle stages of radial stem increment, but ray area and ray proportion did not relate to the stages of radial stem increment.

Study of the Influence of Anatomical Characteristics on Dyeing Effects of Plantation Pinus sylvestnis var. mongolica litv. Veneer

This paper takes plantation pinus sylvestnis var. mongolica litv. as study object, determines main anatomical factors influencing wood dyeing effects by measuring the related indexes of wood anatomical structure and dyeing effects, making a multiple regression analysis of them and analyzing the correlation variation law between wood anatomical structure and dyeing effects. The results show that there is a high correlation between pinus sylvestnis var. mongolica litv. dyeing effects and wood anatomical factors and the multiple correlation coefficients between anatomical factors and various dyeing effect indexes are between 0.573 and 0.786. The main anatomical factors influencing pinus sylvestnis var.mongolica litv.dyeing effects are tracheid proportion, wood ray proportion, resin canal proportion and late wood tracheid length, etc.

Variations in Wood Anatomical Characteristics of Nigerian grown <i>Triplochiton scleroxylon</i> and their Relationships with Selected Mechanical Properties

Anatomical characteristics of wood of 27-year old Triplochiton scleroxylon(obeche) were investigated to assess the variation pattern of fibre, vessel and ray elements. Test samples were obtained axially from butt, 10%, 30%, 50%, 70% and 90% of merchantable height (MH); and radially from inner wood, middle wood and outer wood. Results show that fibre proportion ranged from 53.5% at 90% of MH to 64.7% at the butt. Vessel proportion ranged from 18.85 to 17.1%, while ray proportion had a range of between 16.7% and 26.6%. Axial variation for fibre and vessels were significant at 5% level that of while those of rays were not significant. It was further revealed that variations of fibre diameter and fibre wall thickness generally increased from butt to top of tree, lumen width and fibre length varied inconsistently along the bole. Modulus of Elasticity MOE was the most predictable Strength property, while Impact Bending IMB was least predictable. Addition of fibre proportion to selected fibre dimensional characteristics improved predictability in strength properties except in Maximum compressive strength parallel to grain MCS//. Keywords: Triplochiton scleroxylon, Anatomical properties Strength properties, Omo Forest Reserve, Nigeria Journal of Applied Science, Engineering and Technology Vol. 6 (1) 2006 pp. 68-75

The Alkaline Solution to the Emergence of Life: Energy, Entropy and Early Evolution

The Earth agglomerates and heats. Convection cells within the planetary interior expedite the cooling process. Volcanoes evolve steam, carbon dioxide, sulfur dioxide and pyrophosphate. An acidulous Hadean ocean condenses from the carbon dioxide atmosphere. Dusts and stratospheric sulfurous smogs absorb a proportion of the Sun's rays. The cooled ocean leaks into the stressed crust and also convects. High temperature acid springs, coupled to magmatic plumes and spreading centers, emit iron, manganese, zinc, cobalt and nickel ions to the ocean. Away from the spreading centers cooler alkaline spring waters emanate from the ocean floor. These bear hydrogen, formate, ammonia, hydrosulfide and minor methane thiol. The thermal potential begins to be dissipated but the chemical potential is dammed. The exhaling alkaline solutions are frustrated in their further attempt to mix thoroughly with their oceanic source by the spontaneous precipitation of biomorphic barriers of colloidal iron compounds and other minerals. It is here we surmise that organic molecules are synthesized, filtered, concentrated and adsorbed, while acetate and methane--separate products of the precursor to the reductive acetyl-coenzyme-A pathway-are exhaled as waste. Reactions in mineral compartments produce acetate, amino acids, and the components of nucleosides. Short peptides, condensed from the simple amino acids, sequester 'ready-made' iron sulfide clusters to form protoferredoxins, and also bind phosphates. Nucleotides are assembled from amino acids, simple phosphates carbon dioxide and ribose phosphate upon nanocrystalline mineral surfaces. The side chains of particular amino acids register to fitting nucleotide triplet clefts. Keyed in, the amino acids are polymerized, through acid-base catalysis, to alpha chains. Peptides, the tenuous outer-most filaments of the nanocrysts, continually peel away from bound RNA. The polymers are concentrated at cooler regions of the mineral compartments through thermophoresis. RNA is reproduced through a convective polymerase chain reaction operating between 40 and 100 degrees C. The coded peptides produce true ferredoxins, the ubiquitous proteins with the longest evolutionary pedigree. They take over the role of catalyst and electron transfer agent from the iron sulfides. Other iron-nickel sulfide clusters, sequestered now by cysteine residues as CO-dehydrogenase and acetyl-coenzyme-A synthase, promote further chemosynthesis and support the hatchery--the electrochemical reactor--from which they sprang. Reactions and interactions fall into step as further pathways are negotiated. This hydrothermal circuitry offers a continuous supply of material and chemical energy, as well as electricity and proticity at a potential appropriate for the onset of life in the dark, a rapidly emerging kinetic structure born to persist, evolve and generate entropy while the sun shines.

Studi Perbandingan Metode Sampling Bor Riap dengan Disk untuk Pengukuran Proporsi dan Dimensi Serat Kayu Sengon Salomon (Paraserianthes falcataria, (L.) Nielsen) Comparative Study of Two Types Sampling Method for Measuring Cell Proportion and Fiber Dimension on Sengon Salomon Wood (Paraserianthes falcataria (L.) Nielsen)

The objective of this research was to determine the differentiation on the measurement result of cell proportion and fiber dimension that caused by the different of sampling methods. The research was conducted at the Laboratory of Wood Structure and Properties, Faculty of Forestry, Gadjah Mada University. The research designed with completely random design composed by factorial experiment, which considered two factors, namely: 1) Sampling methods: disk method and drill method, and 2) Radial distribution: center/pitch, center-bark and near bark. Analysis of variance was conducted in order to evaluate the variation in all data of two factors mentioned above. The relationship between sampling method and radial distribution was also evaluated. The data variables were: fiber length, cell diameter, lumen diameter, cell wall thickness, and the proportion of vessel, rays, fiber and parenchyma. The observation on fiber length was conducted by using light microscope or scanning electron microscope. The observation on cell proportion was conducted by using photomicroscope and dot grid. The results of the research showed that the different of sampling methods have not any influenced to the measurement result of cell proportion and fiber dimension on Sengon wood. Whereas the radial distribution of wood has significant influenced in fiber dimension, especially in fiber length and cell wall thickness, but in cell proportion, radial distribution has not influenced.

A long drink of water: how xylem changes with depth.

A long drink of water: how xylem changes with depth.

Evaluation of Protective Eyewear Coverage

In the development of protective eyewear for military operations, conflicting constraints impact design considerations. Since protection is a key parameter, it is important to be able to quantify the impact of different levels of coverage of the visual field. The objective of this project was to merge two different techniques — (a) methodology to verify visual field coverage and (b) ray trace model for pupil accessibility — to produce a coverage metric to represent retinal accessibility to damage from lasers. Data were collected from nine subjects and a computer model was used to determine the proportion of incident rays that could access the pupil. Overall, the combined result provides an efficient methodology to assist when design trade-offs are required in the evaluation of protective spectacles. This technique can be used to quantify the amount of coverage and assign a conservative level of risk to the areas of the visual field that remain uncovered.

Studies on the relationships between wood properties and the quality of veneer and plywood of plantation poplars

Summary In this study three poplar clones, grown on three different beaches of the Yangtse River, and at three different planting densities (3 m × 4 m, 4m × 5m, 5m × 6m) were used to study relationships between wood properties and the quality of veneer and plywood. The results show: (i) The variance of veneer thickness was highly significantly related to fibre width and the proportion of vessels and fibres; and significantly related to the fibre length, the thickness of the cell wall, the ratio of cell wall to cell cavity, the ratio of cell cavity to cell diameter, the length of vessels and the proportion of rays. (ii) The ratio of lathe check in veneer was highly significantly related to only the diameter of the cell cavity. (iii) The glue-bond strength of plywood was highly significantly related to the fibre length, the fibre width, the diameter of cell cavity, the thickness of cell wall, the ratio of cell wall to cell cavity, the vessel length, the tangential diameter of vessels, the microfibril angle, and the proportion of vessels and rays; and significantly related to the proportion of fibres. (iv) The variance of veneer thickness and the ratio of lathe check in veneer were not related to chemical properties, but the glue-bond strength was significantly related to the pH value of sapwood, and highly significantly related to the pH value of heartwood and the average pH value of sapwood and heartwood. (v) The variance of veneer thickness and the glue-bond strength of plywood were not related to physical-mechanical properties, but the ratio of lathe check in veneer was highly significantly related to the modulus of elasticity, and significantly related to the air-dry wood density.

Biomechanical properties of tree saplings and free-standing lianas as indicators of susceptibility to logging damage

Liana infestations often impede natural regeneration of commercially important tree species after selective logging of tropical lowland forests. To help elucidate the genesis of these tangles, the biomechanical properties, stem anatomy and resprouting capacities of tree saplings and free-standing juvenile lianas and their responses to mechanical damage typical of selective logging were investigated in Ulu Segama, Sabah, Malaysia. Tree saplings and free-standing lianas were similar in almost all of the parameters compared. Whole-sapling flexibilities, root–stem junction flexibilities, stem taper, and resprouting capacities of tree saplings and free-standing lianas were not different. The maximum fiber-wall thickness, and proportions of vessel lumena, xylem rays and axial parenchyma per cross-sectional area did not differ. Trees and lianas also suffered similar frequencies of damage and mortality after bulldozer passage. Only the elastic resilience of tree saplings and free-standing lianas differed; tree saplings were slightly more resilient than free-standing lianas. These results suggest that the susceptibility and response of tree saplings and free-standing lianas to mechanical damage is similar. An increase in the density of lianas relative to trees was not observed in surviving vegetation on skid trails. This result suggests that liana tangles frequently encountered in selectively logged tropical forest are not the result of differential survival of trees and lianas.

Woods of Eucalyptus-Part 1 Distinguishing Three Species from the Ash Group

In Australia the ash group of eucalypts comprises approximately 35 species of Eucalyptus from the botanical series Obliquae. They are abundant in south-eastern Australia, but timber of commerce comes mainly from Victoria and Tasmania and includes E. regnans F. Muell., E. delegatensis R.T. Baker and E. obliqua L'Hérit. This group produces some of the fastest growing and the highest yielding hardwood species in Australia. The timbers are similar in appearance and can be interchanged for many uses, but there are some important differences. This study found differences between the species in basic density, distinctness of growth rings and pore grouping, ray width, proportion of multiseriate rays, and the height of the multi seriate proportion of the rays. Differences between mainland and Tasmanian provenances were also observed. Growth rings are prominent in E. delegatensis from the mainland, but less so from Tasmania, and least distinct in E. obliqua. Basic density can be used to distinguish E. obliqua when samples are heavier than 605 kg/ m3, and E. regnans for samples less than 390 kg/m3. Height of the multiseriate portion of the rays is 1-9, mostly 5 cells in E. obliqua, whereas it is 1-5, mostly 1-2(-4) cells high in the other two species; maximum height of the multi seriate portion of the rays is 3-12, mostly 4-8 cells in E. obliqua, 1-6, mostly 1-2 cells in E. delegatensis, and 1-8, mostly 1-3 cells in E. regnans; width of individual ray cells 10-30 µm, mostly 15-20 µm in E obliqua, and 5-16 µm, mostly 8-12 µm in the other two species. A key for separation between the species is given and the similarities to other species are discussed. Other commercially important species will be dealt with subsequently.

Effect of growth rate on the anatomy, specific gravity, and bending properties of wood from 7-year-old red alder (Alnus rubra)

Understanding the association between growth rate and wood properties is of practical importance to maximizing and sustaining wood and fiber production. Anatomical characteristics, specific gravity, and bending properties were determined at breast height for thirty 7-year-old trees with varying growth rates, from a red alder (Alnus rubra Bong.) plantation. Wood was sampled from the growth ring with a cambial age of 5 years. Growth varied from 2.0 to 9.3 mm/year (ring width), or 264 to 3350 mm 2 /year (ring area). We analyzed the relationship between growth rate, in terms of both annual ring width and area, and each wood property. Because both measures of growth rate yielded the same qualitative results, we only used ring width in our analyses. Regression analysis showed that growth rate had no effect on specific gravity, the modulus of elasticity in bending, the modulus of rupture in bending, fiber diameter, or the proportion of growth ring that was fiber or vessel. Fiber length, vessel diameter, and ray proportion, however, were positively correlated with growth rate. Fiber-wall thickness and axial parenchyma proportion decreased slightly with growth rate. The results indicate that the growth rate of A. rubra trees can be increased through silvicultural practices with few negative effects on wood and fiber quality, at least in the juvenile wood zone of the stem.

Proportions of Wood Elements in Stem, Branch, and Root Wood of Black Oak (Quercus Velutina)

The volumetrie proportions of vessel elements, fibres, rays, and axial parenchyma plus vasicentric tracheids were determined for the stern, branch and root wood of threc black oak (Quercus velutina Lam.) trees. There were statistical differences in the proportions of wood elements between locations within the trees sampled, i.e., branches, sterns, roots, oblique roots, and lateral roots. Branches had the highest proportion of vesseI elements, whereas sterns had the greatest proportion ofaxial parenchyma plus vasicentric tracheids. The highest proportions of rays were found in root wood. Fibre proportion was greatest in the stern and branch wood.

Within-tree variation in cambial anatomy and xylem cell differentiation in Eucalyptus globulus

Microscopic examination of the vascular cambium of Eucalyptus globulus, from four trees, at nine height levels, revealed a non-storied cambial structure with both ray and fusiform initials. Average fusiform initial length increased from 443 μm at 70% of tree height from the base to a maximum of 484 μm at 10% of tree height. At 2.5% of tree height average fusiform initial length sharply declined to 438 μm. A strong positive correlation (r = 0.757, df = 7, P <0.05) existed between average fusiform initial length and average fibre length at each height, giving quantitative support to the notion that variation in fusiform initial length is an important mechanism influencing fibre length in hardwoods. However, 62% of the longitudinal variation in average fibre length was explained by the extent of elongation during differentiation, which increased linearly down the stem. At 70% of tree height, the average length of fibres was 1.84 times that of the fusiform initials, compared to 2.11 times at 2.5% of tree height. Concomitant with this longitudinal gradient of elongation was a gradient of increasing tangential area of the cambium occupied by cambial rays. This was accounted for by dimensional increases in the ray initial cells with decreasing height. Possible mechanisms that regulate the elongation of developing fibres and the proportion of cambial rays are discussed.

Therapy of Infections in Mice Irradiated in Mixed Neutron/Photon Fields and Inflicted with Wound Trauma: A Review of Current Work

When host antimicrobial defenses are severely compromised by radiation or trauma in conjunction with radiation, death from sepsis results. To evaluate therapies for sepsis in radiation casualties, we developed models of acquired and induced bacterial infections in irradiated and irradiated-wounded mice. Animals were exposed to either a mixed radiation field of equal proportions of neutrons and gamma rays (n/gamma = 1) from a TRIGA reactor or pure gamma rays from 60[Co sources. Skin wounds (15% of total body surface area) were inflicted under methoxyflurane anesthesia 1 h after irradiation. In all mice, wounding after irradiation decreased resistance to infection. Treatments with the immunomodulator synthetic trehalose dicorynomycolate (S-TDCM) before or after mixed neutron-gamma irradiation or gamma irradiation increased survival. Therapy with S-TDCM for mice irradiated with either a mixed field or gamma rays increased resistance to Klebsiella pneumoniae-induced infections. Combined therapy with S-TDCM and ceftriaxone for K. pneumoniae infections in mice exposed to a mixed radiation field or to gamma rays was more effective than single-agent therapy. In all irradiated-wounded mice, single therapy of acquired infections with an antibiotic or S-TDCM did not increase survival. Survival of irradiated-wounded mice after topical application of gentamicin sulfate cream suggested that bacteria colonizing the wound disseminated systemically in untreated irradiated mice, resulting in death from sepsis. In lethal models of acquired infections in irradiated-wounded mice, significant increases in survival were achieved when systemic treatments with S-TDCM or gentamicin were combined with topical treatments of gentamicin cream. Therapies for sepsis in all mice exposed to a mixed field were less effective than in mice exposed to gamma rays. Nonetheless, the data show a principle by which successful therapy may be provided to individuals receiving tissue trauma in conjunction with radiation injury.

Results of 10 y of radiation protection dosimetry at the neutrontherapy facility in Louvain-la-Neuve.

After 10 y of routine operation, radiation hazards to the neutron therapy staff at Louvain-la-Neuve were evaluated. These hazards to the staff in neutron therapy are a matter of concern, not only because of the dose levels due to induced activation after treatment but also because of the difficulty of evaluating adequately the dose equivalent rates (including the quality factor, QF) during the irradiation. Build-up of radioactivity near the collimator and in the therapy room is reported. In the beam axis, dose rates due to activation can amount up to 5 mGy h-1. However, these rates are efficiently reduced to 0.3 mGy h-1 by automatically withdrawing the target after irradiation. Other problems of radioactive contamination (for instance, the choice of the Fe composition of the collimator) are discussed. Dose equivalent rates were determined during treatment at different positions inside and outside the treatment room. At these locations, neutrons of widely varying energies are present, accompanied by a significant proportion of gamma rays. The measurements of neutron-dose equivalent rates were performed with three commercial neutron detectors: a BF3 and a He3 remcounter (Nuclear Enterprises and Nardeux) and the Dineutron multisphere remcounter (Nardeux). The Dineutron also allowed the evaluation of QF. The results of these detectors were compared with the results of the integration of microdosimetry spectra obtained in free air with a TE proportional counter (Far West Technology). For the p(65) + Be neutrons, the dose equivalent rate was equal to 0.4 Sv h-1 in the treatment room (at 2.5 m from the collimator) and was reduced to 2-3 microSv h-1 at the room entrance. The gamma component increased from 55% to 95% at the same positions, respectively. Ratios of the responses of all detectors and QF values are compared and discussed at the different positions. The whole-body dose equivalents to the neutron therapy staff over the 10 y considered are presented; although they are higher than for conventional radiotherapy, they remain far below the ICRP recommended dose limits.

Wood Anatomical Variation of Acacia Melanoxylon in Relation to Latitude

The wood anatomy of Acacia melanoxylon samples from various locations in eastern Australia was examined and a number of characteristics were found to be significantly related to latitude. Vessel member length, proportion of fibres and proportion of multiseriate rays were positively related to latitude. Vessel frequency, vessel diameter and the abundance of crystals were negatively related to latitude as were the proportion of: uniseriate rays, vessels and axial parenchyma. Total proportion of ray tissue and basic density was not found to be associated with latitude.Anatomical features associated with lower transpirational demand appeared to be correlated with the cooler, more xeric environmental conditions accompanying increasing latitude.

Determination of the Dose Equivalent and the Quality Factor in the Environment of Clinical Neutron Beams

Dose equivalent rates and quality factors or Q factors were determined at the neutron therapy facilities of Louvain-la-Neuve and Orléans at different positions inside and outside the treatment room. At these locations, neutrons of widely varying energies are present, accompanied by a significant proportion of gamma rays. Four clinical neutron beams were studied: p(45)+Be, p(65)+Be and d(50)+Be neutrons at Louvain-la-Neuve and at Orléans, the p(34)+Be neutron beam. The measurements of dose equivalent rates were performed with three commercial neutron detectors: a 'BF3' and a 'He3' rem counter (Nuclear Enterprises and Nardeux) and the 'Dineutron' multisphere rem counter (Nardeaux). The last counter also allowed the evaluation of the mean Q factors. The results from both detectors were compared with the results of the integration of microdosimetry spectra. These were obtained free-in-air with a TE proportional counter (Far West Technology) at Orléans and at Louvain-la-Neuve and, in addition at Orléans, the portable CIRCLE counter (Fontenay-aux-Roses). For the p(65)+Be neutrons (proton current of 12.5 µA), the dose equivalent rate was equal to 0.4 Sv.h-1 in the treatment room at 2.5 m from the collimator, and was reduced to 2-3 µSv.h-1 at the room entrance. The gamma component ranged from 55% to 95%. The Dineutron counter indicated a Q factor of 5.2 close to the treatment room which was reduced to 4.5 at the entrance. Evaluation of the microdosimetry spectra led to 4.9 and 1.6 for Q in the mixed beam, respectively, at the same positions. For the neutrons only, Q was equal to about 10 for all positions. Ratios of the responses of all detectors are compared and discussed at the various positions for the different neutron beams.

The detection of the inelastic scattering of gamma rays at crystal diffraction maxima using the Mössbauer effect

The Mossbauer effect is used to distinguish the elastically and inelastically scattered components at Bragg diffraction peaks of x rays from single crystals of lithium fluoride. The proportion of gamma rays emitted without recoil by a Mossbauer source is found by observing their resonant absorption. The Mossbauer source was 10 mC of Co/sup 57/ diffused in metallic iron-56. The resonant absorber was a metallic iron foil of 80% Fe/sup 57/. (R.E.U.)