Physical Properties of Woody Fuel Particles of Sierra Nevada Conifers

1996 ◽  
Vol 6 (3) ◽  
pp. 117 ◽  
Author(s):  
JW Van Wagdendonk ◽  
JM Benedict ◽  
WM Sydoriak
Keyword(s):  
Physical Properties ◽  
Sierra Nevada ◽  
Fire Behavior ◽  
Volume Ratio ◽  
Rocky Mountain ◽  
Average Diameter ◽  
Size Class ◽  
Quadratic Mean ◽  
Quadratic Mean Diameter ◽  
Fuel Particles

A study of the physical properties of Sierra Nevada conifer fuel particles showed that average diameter, squared quadratic mean diameter, surface-area-to-volume ratio, and specific gravity varied significantly by species for all four timelag fuel diameter size classes. The nonhorizontal angle was not significantly affected by size class, and the developmental stage of the overstory did not affect any of the properties. These values are used to calculate fuel weight and predict fire behavior. Regional variation in physical properties can result in fuel weight estimates for the Sierra Nevada that differ from under 40.8 percent to over 8.3 percent from those calculated from Rocky Mountain values. These differences made small changes in predicted fire behavior.

Novel fuelbed characteristics associated with mechanical mastication treatments in northern California and south-western Oregon, USA

2009 ◽  
Vol 18 (6) ◽  
pp. 686 ◽  
Author(s):  
Jeffrey M. Kane ◽  
J. Morgan Varner ◽  
Eric E. Knapp
Keyword(s):  
Time Lag ◽  
Fire Behavior ◽  
Fuel Load ◽  
Northern California ◽  
Fuel Loading ◽  
Quadratic Mean ◽  
Fuel Models ◽  
Quadratic Mean Diameter ◽  
Fuel Particles ◽  
Particle Shapes

Mechanically masticated fuelbeds are distinct from natural or logging slash fuelbeds, with different particle size distributions, bulk density, and particle shapes, leading to challenges in predicting fire behavior and effects. Our study quantified some physical properties of fuel particles (e.g. squared quadratic mean diameter, proportion of non-cylindrical particles) and surface fuel loading with planar intercept and plot-based methods in 10 mechanically masticated sites in northern California and south-western Oregon. Total woody fuel load differed among masticated sites, ranging from 15.3 to 63.4 Mg ha–1, with the majority of the load concentrated in the 10-h (53.7%) and 1-h (29.2%) time-lag classes. Masticated fuels were densely packed, with total depths ranging from 4.6 to 8.0 cm and fuelbed bulk densities ranging from 45.9 to 115.3 kg m–3. To accurately quantify loading in masticated fuelbeds, we recommend using a hybrid methodology, where 1-h and 10-h fuel loadings are estimated using a plot-based method and 100-h and 1000-h fuel loadings are estimated using the standard planar intercept method. Most masticated fuelbeds differed in loading by fuel class and fuelbed depth, when compared with existing natural and slash-based fuelbeds, suggesting new fire behavior fuel models specific to masticated fuelbeds may be warranted.

scholarly journals Solar-blind ultraviolet photodetector based on vertically aligned single-crystalline β-Ga2O3 nanowire arrays

Nanophotonics ◽  
2020 ◽  
Vol 9 (15) ◽  
pp. 4497-4503
Author(s):  
Liying Zhang ◽  
Xiangqian Xiu ◽  
Yuewen Li ◽  
Yuxia Zhu ◽  
Xuemei Hua ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Light Trapping ◽  
High Surface ◽  
Volume Ratio ◽  
Average Diameter ◽  
Nanowire Arrays ◽  
Etching Technique ◽  
Inductively Coupled ◽  
Solar Blind ◽  
Vertically Aligned

AbstractVertically aligned nanowire arrays, with high surface-to-volume ratio and efficient light-trapping absorption, have attracted much attention for photoelectric devices. In this paper, vertical β-Ga2O3 nanowire arrays with an average diameter/height of 110/450 nm have been fabricated by the inductively coupled plasma etching technique. Then a metal-semiconductor-metal structured solar-blind photodetector (PD) has been fabricated by depositing interdigital Ti/Au electrodes on the nanowire arrays. The fabricated β-Ga2O3 nanowire PD exhibits ∼10 times higher photocurrent and responsivity than the corresponding film PD. Moreover, it also possesses a high photocurrent to dark current ratio (Ilight/Idark) of ∼104 and a ultraviolet/visible rejection ratio (R260 nm/R400 nm) of 3.5 × 103 along with millisecond-level photoresponse times.

scholarly journals PHOSPHORUS FERTILIZATION AND HARVEST INTERVALS INFLUENCE ENERGETIC AND PHYSICAL PROPERTIES OF BRIQUETTES AND LARGE BRANCHES OF MATE

2017 ◽  
Vol 41 (1) ◽  
Author(s):  
Delmar Santin ◽  
Marcelino Breguez Gonçalves Sobrinho ◽  
Angélica de Cássia Oliveira Carneiro ◽  
Eliziane Luiza Benedetti ◽  
Nairam Félix de Barros
Keyword(s):  
Physical Properties ◽  
Basic Density ◽  
Calorific Value ◽  
Average Diameter ◽  
Plant Residue ◽  
Phosphorus Fertilization ◽  
P Availability ◽  
Gross Calorific Value ◽  
Energetic Properties ◽  
Harvest Intervals

ABSTRACT In mate crop, the commercial part consists of leaves and thin branches, while the large branches (LB) are considered unused residues and left in the field, although they may have potential for use as energy. The objective of this paper was to evaluate the influence of phosphorus fertilization and harvest interval in productivity of mate large branches and in their physical and energetic properties, as well as in derived briquettes. In a seven-year-old plantation, doses of 0, 20, 40, 80, 160 and 320 kg.ha-1 of P2O5 were applied considering harvest intervals of 12, 18 and 24 months. Dry mass, average diameter, P content, and physical and energetic properties of LB were determined. With LB, after its transformation into particles and briquetting, physical and energetic properties were determined, as well as P availability in soil. The phosphorus fertilization increased LB productivity in larger harvest intervals, increasing the amount of energy produced per unit of area, but did not change basic density and gross calorific value of wood. Mate harvest intervals did not affect the apparent density and calorific value of briquettes produced by LB. LB harvested at intervals of 18 and 24 months produced wood with higher basic density and gross calorific value. LB or briquettes have adequate energetic and physical properties, being technically a plant residue with great potential for use as energy.

scholarly journals Nestling Growth and Thermoregulatory Development in Subalpine Dusky Flycatchers

The Auk ◽  
2001 ◽  
Vol 118 (1) ◽  
pp. 116-136 ◽  
Author(s):  
Maria Elena Pereyra ◽  
Martin L. Morton
Keyword(s):  
Sierra Nevada ◽  
Volume Ratio ◽  
Cold Temperatures ◽  
Neotropical Migrant ◽  
Nestling Growth ◽  
Ambient Temperatures ◽  
Thermal Environments ◽  
Dusky Flycatcher ◽  
Rates Of Growth ◽  
Empidonax Oberholseri

Abstract The Dusky Flycatcher (Empidonax oberholseri), a small, open-nesting Neotropical migrant, is a relatively common summer inhabitant of subalpine environments in the western and southwestern United States. Nestling growth and development of thermoregulation were studied in a population at Tioga Pass (3,000 m) in the eastern Sierra Nevada of California. Despite the selective advantages that might be expected from accelerating rates of growth and thermoregulatory development, in an environment where the season was relatively short and cold temperatures and inclement weather were common, there was little evidence of adaptive modification in either of those parameters; growth rates were comparable to those of other tyrant flycatchers. Feather eruption began around day 5, brushing in dorsal and ventral tracts began two days later, and brushing of the flight feathers around day 9. Asymptotic body masses were attained around day 12, but nestlings did not fledge for another 4 to 5 days. The physiological development of endothermy was closely correlated with increases in body mass and accompanying decreases in surface-area-to-volume ratio and age, but was not significantly correlated with changes in plumage development, when mass and age were statistically controlled. On exposure to ambient temperatures between −3 and 5°C for 10 min (roughly twice as long as the average female bout of inattentiveness), individual nestlings were unable to prevent deep hypothermia until after day 7. Homeothermy, at 80% of adult levels, was not attained until after day 12, although broods of nestlings maintained relatively stable body temperatures as early as day 5. Whereas clutch sizes in this population generally ranged from two to four eggs, the most stable thermal environments were provided by broods of three or four chicks. Although broods of nestlings were generally able to maintain temperatures within 5°C of adult levels, temperature profiles during storms indicated a remarkable capacity for nestlings to tolerate temperatures in the nest as low as 15°C for periods as long as 4 h without apparent ill effect.

scholarly journals Study on the Physical Properties of a SiNW Biosensor to the Sensitivity of DNA Detection

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5716
Author(s):  
Siti Noorhaniah Yusoh ◽  
Khatijah Aisha Yaacob
Keyword(s):  
Surface Roughness ◽  
Physical Properties ◽  
Limit Of Detection ◽  
Silicon Nanowire ◽  
Volume Ratio ◽  
Silicon Nanowire Arrays ◽  
Atomic Force ◽  
Local Anodic Oxidation ◽  
Wet Chemical ◽  
Biosensor Device

SiNW (silicon nanowire) arrays consisting of 5- and 10-wires were fabricated by using an atomic force microscope—the local anodic oxidation (AFM-LAO) technique followed by wet chemical etching. Tetramethylammonium hydroxide (TMAH) and isopropyl alcohol (IPA) at various concentrations were used to etch SiNWs. The SiNWs produced were differed in dimension and surface roughness. The SiNWs were functionalized and used for the detection of deoxyribonucleic acid (DNA) dengue (DEN-1). SiNW-based biosensors show sensitive detection of dengue DNA due to certain factors. The physical properties of SiNWs, such as the number of wires, the dimensions of wires, and surface roughness, were found to influence the sensitivity of the biosensor device. The SiNW biosensor device with 10 wires, a larger surface-to-volume ratio, and a rough surface is the most sensitive device, with a 1.93 fM limit of detection (LOD).

scholarly journals The efficacy of fire and fuels reduction treatments in a Sierra Nevada pine plantation

2009 ◽  
Vol 18 (7) ◽  
pp. 791 ◽  
Author(s):  
Leda N. Kobziar ◽  
Joe R. McBride ◽  
Scott L. Stephens
Keyword(s):  
Sierra Nevada ◽  
Prescribed Fire ◽  
Large Scale ◽  
Structural Characteristics ◽  
Fire Behavior ◽  
Pine Plantation ◽  
Understorey Vegetation ◽  
Fuels Reduction ◽  
Reduction Techniques ◽  
Reducing Potential

Plantations are the most common means of reforestation following stand-replacing wildfires. As wildfires continue to increase in size and severity as a result of fire suppression or climate change, establishment of plantations will likely also increase. Plantations’ structural characteristics, including dense, uniform spacing and abundant ladder fuels, present significant wildfire hazards. Large-scale fuels reduction techniques may be necessary to reduce potential fire behavior in plantations and to protect surrounding forests. In the present study, four different manipulations aimed at reducing potential fire behavior in a Sierra Nevada pine plantation are compared. The treatments include: mechanical shredding, or mastication, of understorey vegetation and small trees; mastication followed by prescribed fire; fire alone; and controls. Fire behavior modeling shows that mastication is detrimental whereas prescribed fire is effective in reducing potential fire behavior at moderate to extreme weather conditions. Predicted fire behavior was compared with actual values from the prescribed burns in an effort to explore the limitations of fire modeling. Fire behavior predictions were similar to field observations in the more structurally homogeneous stands, but differed greatly where mastication created forest openings and patchy fuels distributions. In contrast to natural stands, the homogeneity of pine plantations make the results of the present work applicable to other regions such as the south-eastern US, where similar fuels reduction techniques are used to increase fire-resistance and stand resilience.

A Stocking Guide for Southern Bottomland Hardwoods

1995 ◽  
Vol 19 (3) ◽  
pp. 103-104 ◽  
Author(s):  
J. C. G. Goelz
Keyword(s):  
Basal Area ◽  
Bottomland Hardwoods ◽  
Quadratic Mean ◽  
Mean Diameter ◽  
Quadratic Mean Diameter

Abstract A stocking guide was developed from the data of Putnam, et al. (1960). The form of the stocking guide follows Gingrich (1967), although the “B”-line is based on the suggested residual stocking of Putnam, et al. (1960) rather than on minimum full stocking. This stocking guide is similar to the stocking guide for central upland hardwoods constructed by Gingrich, except that 100% stocking is 5-7 ft2² of basal area lower for the southern bottomland guide, across a range of quadratic mean diameter. South. J. Appl. For. 19(3):103-104.

Community composition and allometry of Leucothoe davisiae, Cornus sericea, and Chrysolepis sempervirens

2014 ◽  
Vol 44 (6) ◽  
pp. 677-683 ◽  
Author(s):  
James A. Lutz ◽  
Kaitlyn A. Schwindt ◽  
Tucker J. Furniss ◽  
James A. Freund ◽  
Mark E. Swanson ◽  
...  
Keyword(s):  
Sierra Nevada ◽  
Explanatory Power ◽  
Fire Behavior ◽  
Total Biomass ◽  
Fuel Loading ◽  
Basal Diameter ◽  
Cornus Sericea ◽  
Forest Dynamics Plot ◽  
Shrub Patches ◽  
Species Specific

Leucothoe davisiae Torr. ex A. Gray (Ericaceae), Sierra laurel, is an endemic shrub of the Sierra Nevada, Klamath Mountains, and Warner Mountains. We compared the woody plant community and allometry of Leucothoe with one widespread wetland shrub, red osier dogwood (Cornus sericea L. (Cornaceae)), and one widespread upland shrub, bush chinquapin (Chrysolepis sempervirens (Kellogg) Hjelmq. (Fagaceae)), in an Abies concolor – Pinus lambertiana forest. We examined 2282 mapped shrub patches and 34 392 trees in the Yosemite Forest Dynamics Plot (25.6 ha), Yosemite National Park, California, USA. We dissected 40–41 stems of each shrub species and determined foliage, bark, wood, and total biomass as a function of stem diameter. Community compositions determined from plants within a 5 m buffer of Leucothoe were different from those reported for Leucothoe communities in the Siskiyou National Forest and the Central Klamath. Leucothoe allometry based on basal diameter was more variable (total biomass R2 = 0.64; P < 0.001) than that of Cornus (R2 = 0.93; P < 0.001) or Chrysolepis (R2 = 0.95; P < 0.001), reflecting greater canopy variation. Allometry based on diameter at 1.37 m along the main stem offered equivalent explanatory power for Cornus (R2 = 0.89; P < 0.001) and Chrysolepis (R2 = 0.84; P < 0.001), but Leucothoe rarely reached that stature. These allometric equations that we report can improve species-specific modeling of carbon dynamics, fuel loading, and fire behavior.

The Effect of Particle Size of Zinc Oxide on the Physical Properties of Rubber

1933 ◽  
Vol 6 (2) ◽  
pp. 288-298
Author(s):  
G. S. Haslam
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
Physical Properties ◽  
Specific Surface ◽  
Distribution Curve ◽  
Average Diameter ◽  
Microscopic Method ◽  
Effect Of Particle Size ◽  
Method Of Measurement ◽  
Number Of Particles

Abstract The particle size of the pigment may be expressed in terms of several average diameters, depending on the method of measurement. In this work three of these averages were considered; namely, d1, which is the arithmetical mean, d3, which is the average diameter from which specific surface is calculated, and D, which is the average diameter from which the number of particles per gram is calculated. A series of samples was prepared and these three average diameters were determined These samples were then compounded with rubber and several physical properties measured. As a result of these tests it is shown that, in general, the physical properties vary directly as the specific surface and the number of particles per gram. However, if the number of particles per gram is maintained constant and the specific surface is varied, it was found that the physical properties vary directly as the specific surface. No such relationship was found when the specific surface was maintained constant and number of particles per gram varied. It is further pointed out that the only satisfactory means of measuring the d3 diameter, and therefore the specific surface, is by some microscopic method which determines the size-distribution curve for the pigment.

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