Cone Diameter Research Articles

Simulation of generalized Newtonian fluids with the Smoothed Particle Hydrodynamics method

AbstractIn this paper we examine Direct Numerical Simulation DNS of single phase non‐Newtonian fluids described by a generalized Newtonian rheology. Non‐Newtonian flow including large deformations and free surface flow could be observed in a wide range of industrial and environmental applications. For that reason, we choose the Lagrangian Smoothed Particle Hydrodynamics (SPH) as a simulation tool. The non‐Newtonian solver is implemented into the general purpose particle framework HOOMD‐blue [1,2], which allows for massive parallel CPU and GPU simulations. Numerical accuracy of the model is demonstrated by simulating confined Poiseuille flow between parallel plates. The validation has been done for a wide variety of shear strain–shear stress ratios where also the effect of the solid‐fluid interface boundary condition is examined. Furthermore, a comparison with the experimental results for the broken dam problem [3] showed good accuracy of the free‐surface flow prediction. Additionally, we have investigated a slump test (Abrams cone [4]), a relatively simple but in practice often performed experiment for non‐Newtonian yield‐stress fluids. Finally, we have investigated in further detail the cone diameter, height, flow time, the final shape and the influence of the rheological model parameters as well as the boundary conditions related to the stationary cone configuration.

Atomization characteristics of aerosol spray from hair spray vessel with various design parameters

Aerosol sprays are used in many fields because they are easy to use and low in cost. Because flash-boiling has a great influence on atomization performance and spray characteristics such as droplet diameter and spray cone angle of aerosol spray, it is necessary to adjust the flash-boiling by changing the internal design of the aerosol vessel to obtain the desired atomization performance. Therefore, spray structure formed on the outside of nozzle during both transient and steady state. with various nozzle design and internal liquid/propellant composition ratio were observed in this study. The spray development process was visualized using a high-speed camera and Nd:Yag laser was used to form a laser sheet and it illuminates the internal structure of spray at steady state. In addition, the diameter and velocity of spray droplets were measured by PDPA equipment, which uses a noninvasive method. Selected design parameters were the number of stem orifice and the diameter of under-tap of the valve and vapor phase tap, and the mass fraction of propellant inside the aerosol vessel. As the diameter of the under tap increased, the ratio of the high-density area increased. However, as the difference between the area of the under-tap orifice and the total area of the stem orifice became smaller, the spray cross section area became larger and the shape of low-density region became closer to the concentric circle. In addition, finer droplets were generated in case with large stem orifice & smaller under-tap. The Vapor Phase Tap and propellant mass fraction have the greatest influence on the atomization characteristics of all design parameters because they change the gas phase ratio inside the jet. However, higher propellant mass fraction makes more uniform droplet diameter distribution than increased vapor phase tap diameter.

Variability of stone pine (Pinus pinea L.) fruit traits impacting pine nut yield

Cone to pine nut yield (PY), an important commercial feature of stone pine cropping, was higher in Chile than in main producer countries. PY is highly variable along years and depends on pine nut number inside cones, followed by pine nut weight. Cone morphometry is not a good indicator of PY, thus selecting cones for size/weight will not improve it. Stone pine nuts are highly appreciated; however, pine nut yield (total pine nut weight as percentage of cone weight), important feature for the species cultivation, is variable and decreasing worldwide. Evaluating inter-annual and spatial variability of fruit traits impacting pine nut yield. Across years and plantation variability of fruit features were estimated from a multi-environment study monitored during 6 years in Chile. Variance component restricted maximum likelihood estimates were calculated for 14 fruit traits. Classification and Regression Tree (CART) was used to identify the variable best explaining pine nut yield. Pine nut yield (3.6–5%) was higher than in main producer countries. Cone weight (521 g), length and diameter were correlated to most of seed and pine nut traits, but not to pine nut yield. The most important fruit trait in determining pine nut yield was pine nut number per cone, followed by pine nut weight. Pine nut yield showed high inter-annual and within plantation variability, whereas pine nut weight more spatial than temporal variability. Pine nut yield was superior in cones containing over 78 pine nuts. Pine nut yield has high inter-annual variability, with cone morphometry not being a good indicator, thus selecting cones for size/weight will not improve cone to pine nut yield.

An Experimental Slope Method for a More Accurate Measurement of Relative Radiation Doses using Radiographic and Radiochromic Films and Its Application to Megavoltage Small-Field Dosimetry.

Purpose:An experimental method using the linear portion of the relative film dose–response curve for radiographic and radiochromic films is presented, which can be used to determine the relative depth doses in a variety of very small, medium, and large radiation fields and relative output factors (ROFs) for small fields.Materials and Methods:The film slope (FS) method was successfully applied to obtain the percentage depth doses (PDDs) for external beams of photon and electrons from a Synergy linear accelerator (Elekta AB, Stockholm, Sweden) under reference conditions of 10 cm × 10 cm for photon beam and nominal 10 cm × 10 cm size applicator for electron beam. For small-field dosimetry, the FS method was applied to EDR2 films (Carestream Health, Rochester, NY) for 6 MV photon beam from a linac (Elekta AB, Stockholm, Sweden) and small, circular radiosurgery cones (Elekta AB, Stockholm, Sweden) with diameters of 5, 7.5, 10, 12.5, and 15 mm. The ROFs for all these cones and central axis PDDs for 5, 10, and 15 mm diameter cones were determined at source-to-surface distance of 100 cm. The ROFs for small fields of CyberKnife system were determined using this technique with Gafchromic EBT3 film (Ashland, NJ, USA). The PDDs and ROFs were compared with ion chamber (IC) and Monte Carlo (MC) simulated values.Results:The maximum percentage deviation of PDDFS with PDDIC for 4, 6, and 15 MV photon beams was within 1.9%, 2.5%, and 1.4%, respectively, up to 20-cm depth. The maximum percentage deviation of PDDFS with PDDIC for electron beams was within 3% for energy range studied of 8–15 MeV. The gamma passing rates of PDDFS with PDDIC were above 96.5% with maximum gamma value of >2, occurring at the zero depths for 4, 6, and 15 MV photons. For electron beams, the gamma passing rates between PDDFS with PDDIC were above 97.7% with a maximum gamma value of 0.9, 1.3, and 0.7 occurring at the zero depth for 8, 12, and 15 MeV. For small field of 5-mm cone, the ROFFS was 0.665 ± 0.021 as compared to 0.674 by MC method. The maximum percentage deviation between PDDFS and PDDMC was 3% for 5 mm and 10 mm and 2% for 15 mm cones with 1D gamma passing rates, respectively, of 95.5%, 96%, and 98%. For CyberKnife system, the ROFFS using EBT3 film and MC published values agrees within 0.2% for for 5 mm cone.Conclusions:The authors have developed a novel and more accurate method for the relative dosimetry of photon and electron beams. This offers a unique method to determine PDD and ROF with a high spatial resolution in fields of steep dose gradient, especially in small fields.

Experimental inspection of the dosing-sowing device by unmanned aerial vehicle for the resettlement of trichogrammes

Purpose. Improving the quality of the trichograms' resettlement by establishing rational operating modes of the dosing and sowing device of an unmanned aerial vehicle. Methods. Experimental studies using the method of planning a three-factor experiment, methods of statistical data processing. Results. Based on the analysis of the technical means for resettlement of the trichograms, the design of the dosing-sowing device of a unmanned aerial vehicle for the resettlement of the trichogram was substantiated. As a result of the experimental studies, it was established that during the deployment of a trichogram with a dosing-seeding device, a stable leakage of the material due to ejection was ensured by using diaphragms with a diameter of 2.5 mm or more. According to the results of the research it was established that with the increase in flight altitude, the quality of material distribution does not change significantly. But factors such as the height of the plants and the presence of obstacles on the field must be taken into account, so it is necessary to keep the flight altitude not less than 5 m. Due to changing the size of the confuser, the range of flight of the particle did not change, which leads to the conclusion to use a smaller cone of diameter due to which reduces the frontal resistance. When using a dosing-seeding device for resettlement of a trichogram on a quadracycle, due to air flow from propellers, the width of the capture significantly decreases. Therefore, for the qualitative distribution of biomaterials on the surface of the field, the distance between adjacent passages should be 6 m. Conclusions 1. The height of the flight of an unmanned aerial vehicle during the resettlement of the trichogram must not be less 5 m from the upper edge of the plant. 2. The uniform distribution of material on the surface of the field depends on the flight speed, which should be within the range of 3–5 m/s. 3. The quality of the material distribution increases from the right choice of the width of the ceiling, which should be about 6 m. Conclusions: dosing sowing device, ejector, unmanned aerial vehicle, biological protection of plants, reshaping of trichograms, norm of settlement, width of capture.

Experimental characterization of an extended electrohydrodynamic cone-jet with a hemispherical nozzle

An extended Taylor cone-jet mode is experimentally characterized using a recently introduced hemispherical nozzle. Ethanol is used as the working fluid, and the nozzle produces a much broader range of flow rate and stability of the cone-jet mode. High-resolution images are captured using a high-power light-emitting diode in precise lighting operations to characterize the liquid behavior. Various regimes in the extended cone-jet mode are recognized and mapped in a plane of electro-Weber and Bond numbers. The cone profiles are quantified regarding dimensionless groups, and a related self-similarity is introduced. The cone elongates with the electro-Weber number but retracts as the Bond number increases. The cone and jet diameters are also quantified from the nozzle exit to where the jet begins a transition to instability. It is shown that jet diameter increases with the electro-Weber number powered by 0.75, but it is independent of the Bond number. The meniscus lengths are reported at different electro-Weber and Bond numbers too, and the corresponding correlations are obtained. Finally, jet whipping and spray envelopes are illustrated at various dimensionless numbers, while a wider spray envelope and a dual distribution are recognized at higher electro-Weber numbers.

Light propagation and capture in cone photoreceptors.

The light capturing properties of cone photoreceptors create the elementary signals that form the basis of vision. Variation in the amplitude of individual cone signals has been found physiologically as part of normal retinal circuit processing. Less well characterized is how cone signals may vary due to purely optical properties. We present a model of light propagation in cones using a finite difference beam propagation method to simulate how light from a small stimulus travels through a cone plus its immediate neighbors. The model calculates the amount of light absorbed in the cone outer segments, from which an estimate of the photoresponse can be made. We apply the method to adaptive optics microstimulation to find the optimum optical conditions that will confine the most light into a single cone in the human retina. We found that light capture is especially sensitive to beam size at the pupil and to the cone diameter itself, with the two factors having a complex relationship leading to sizable variation in light capture. Model predictions were validated with two types of psychophysical data. The model can be employed with arbitrary stimuli and photoreceptor parameters, making it a useful tool for studying photoreceptor function in normal or diseased conditions.

Detectors assessment for stereotactic radiosurgery with cones.

The purpose of this work is to assess eight detectors performance for output factor (OF), percent depth dose (PDD), and beam profiles in a 6‐MV Clinac stereotactic radiosurgery mode for cone irradiation using Monte Carlo simulation as reference. Cones with diameters comprised between 30 and 4 mm have been studied. The evaluated detectors were ionization chambers: pinpoint and pinpoint 3D, diodes: SRS, P and E, Edge, MicroDiamond and EBT3 radiochromic films. The results showed that pinpoints underestimate OF up to −2.3% for cone diameters ≥10 mm and down to −12% for smaller cones. Both nonshielded (SRS and E) and shielded diodes (P and Edge) overestimate the OF respectively up to 3.3% and 5.2% for cone diameters ≥10 mm and in both cases more than 7% for smaller cones. MicroDiamond slightly overestimates the OF, 3.7% for all the cones and EBT3 film is the closest to Monte Carlo with maximum difference of ±1% whatever the cone size is. For the profiles and the PDD, particularly for the small cones, the size of the detector predominates. All diodes and EBT3 agree with the simulation within ±0.2 mm for beam profiles determination. For PDD curve all the active detectors response agree with simulation up to 1% for all the cones. EBT3 is the more accurate detector for beam profiles and OF determinations of stereotactic cones but it is restrictive to use. Due to respectively inappropriate size of the sensitive volume and composition, pinpoints and diodes do not seem appropriate without OF corrective factors below 10 mm diameter cone. MicroDiamond appears to be the best detector for OF determination regardless all cones. For off‐axis measurements, the size of the detector predominates and for PDD all detectors give promising results.

Prototype modulated orthovoltage stereotactic radiosurgery cones

This work sought create a set of prototype modulated orthovoltage stereotactic radiosurgery (SRS) cones, and to perform a dosimetric characterization of the prototypes. Four radiosurgical cone collimators (with cone diameters of 5 mm, 6 mm, 8 mm, and 10 mm) were built for use with an orthovoltage unit, along with epoxy-infiltrated bonded tungsten filters designed to shape the resulting dose distributions. Dosimetry measurements were performed using radiochromic film in a water phantom for both filtered and unfiltered cones at depths of 2.5 cm, 5.0 cm, and 7.5 cm. Films were scanned using a flatbed scanner and the beam profiles were analyzed. Extracted beam profiles validated the ability to optimize dosimetric results based on desired dose distributions, where for this work the goal distributions were rectangular functions. Radiochromic film measurements of dose distributions in water confirmed that the prototypes were able to achieve distributions approaching rectangular functions at depth, as determined by penumbra and flatness statistics. A prototype set of novel, modulated orthovoltage SRS filtered cones was successfully constructed, and a full dosimetric characterization was completed in water. In all configurations, filtered, optimized cones were able to achieve distributions more closely approaching the goal distributions compared to open cones.

Cone Photoreceptor Cell Segmentation and Diameter Measurement on Adaptive Optics Images Using Circularly Constrained Active Contour Model.

PurposeCone photoreceptor cells can be noninvasively imaged in the living human eye by using nonconfocal adaptive optics scanning ophthalmoscopy split detection. Existing metrics, such as cone density and spacing, are based on simplifying cone photoreceptors to single points. The purposes of this study were to introduce a computer-aided approach for segmentation of cone photoreceptors, to apply this technique to create a normal database of cone diameters, and to demonstrate its use in the context of existing metrics.MethodsCone photoreceptor segmentation is achieved through a circularly constrained active contour model (CCACM). Circular templates and image gradients attract active contours toward cone photoreceptor boundaries. Automated segmentation from in vivo human subject data was compared to ground truth established by manual segmentation. Cone diameters computed from curated data (automated segmentation followed by manual removal of errors) were compared with histology and published data.ResultsOverall, there was good agreement between automated and manual segmentations and between diameter measurements (n = 5191 cones) and published histologic data across retinal eccentricities ranging from 1.35 to 6.35 mm (temporal). Interestingly, cone diameter was correlated to both cone density and cone spacing (negatively and positively, respectively; P < 0.01 for both). Application of the proposed automated segmentation to images from a patient with late-onset retinal degeneration revealed the presence of enlarged cones above individual reticular pseudodrusen (average 23.0% increase, P < 0.05).ConclusionsCCACM can accurately segment cone photoreceptors on split detection images across a range of eccentricities. Metrics derived from this automated segmentation of adaptive optics retinal images can provide new insights into retinal diseases.

Silicon nanocone formation via low-energy helium ion sputtering

In this study, the effect of low-energy (100 eV) He+ ion irradiation on Si surface morphology is explored. Si (100) and (111) samples were irradiated with 100 eV He+ ions at an elevated sample temperature of 600 °C and to fluences in the range 5.0 × 1019–2.0 × 1020 ions cm–2. Through a combination of high ion flux and high sample temperature, it was found that continued He+ ion irradiation facilitates the formation of homogeneously populated, high aspect ratio silicon nanocones (NCs) (∼50–100 nm base and ∼200–400 nm height). The resulting surface morphology is shown to have excellent antireflective properties, suggesting potential application toward enhanced light absorption in photovoltaic and other optical applications. Furthermore, similar irradiations at reduced sample temperature show comparable structuring mechanisms but with smaller cone diameter. These results indicate that NC size and number density (and related wavelength-dependent reflectivity properties) may be tailored by carefully tuning ion irradiation conditions. Utilizing very low-energy He+ ions as the irradiating species, these studies also demonstrate an added benefit to limiting metallic surface contamination through reduced probability of sputtering in-vacuum components.

Diameter and Taper Variability of Single-file Instrumentation Systems and Their Corresponding Gutta-percha Cones

IntroductionManufacturers offer single-file instrumentation systems with matching gutta-percha (GP) cones to simplify root canal preparation and obturation. The purpose of this study was to determine whether file diameters and tapers match with corresponding cone diameters and tapers (precision) as well as industry standards (accuracy). MethodsTwenty files and corresponding GP cones from each size of F360 (#25, #35, #45, #55 with .04 taper) and Reciproc (#25, #40, #50 with variable tapers) instruments were examined by using optical microscopy (×32) to determine their diameter and taper. Precision was evaluated by using one-way analysis of variance (α = 0.05) with Scheffé post hoc tests and t tests with Bonferroni correction. Accuracy was calculated by subtracting the nominal values from the measured values of all files and GP cones, and mean diameter and taper differences were compared by using one-way analysis of variance (α = 0.05) and Scheffé post hoc test for pairwise comparison. ResultsFor F360, the majority of file and cone diameters were within the tolerance levels, but most of the file diameters were significantly larger than GP cone diameters (P < .05), but the majority of all measured values were within the tolerance levels. For Reciproc, file and cone diameters at D1 and D3 mostly approached the nominal values. At the coronal end, file diameters #25 and #50 were significantly smaller than cone diameters (P < .05). For both instrumentation systems, almost all file and cone tapers matched with the preset tolerance ranges. For Reciproc, significant differences between file and GP cone demonstrated either smaller cone or smaller file diameters and tapers, depending on the size. Most of the measured values were within the acceptable range, but diameters at the coronal end exhibited the highest percent difference from the nominal values. ConclusionsDespite the call for standardization, variability in diameter and taper dimensions between single-file instrumentation systems and their corresponding GP cones can be expected.

Experimental and Numerical Analysis of Expanded Pipe using Rigid Conical Shape

The experimental and numerical analysis was performed on pipes suffering large plastic deformation through expanding them using rigid conical shaped mandrels, with three different cone angles (15◦, 25◦, 35◦) and diameters (15, 17, 20) mm. The experimental test for the strain results investigated the expanded areas. A numerical solution of the pipes expansion process was also investigated using the commercial finite element software ANSYS. The strains were measured for each case experimentally by stamping the mesh on the pipe after expanding, then compared with Ansys results. No cracks were generated during the process with the selected angles. It can be concluded that the strain decreased with greater angles of conical shape and an increase in expansion ratio results in an increase of expansion force and a decrease in the pipe thickness and length resulting in pipe thinning and shortening. Good agreement is evident between experimental and ANSYS results within discrepancy (16.90017%) in the X direction and (27.68698%) in the Y direction. Also, the stress distribution is investigated and it can be concluded that the case of Diameter (Do cone) = 35mm and (A) = α = 15° is the optimum.&#x0D;

Application of shell jetting analysis to determine the location of the virtual origin in shaped charges

Shaped charges are designed to produce high-velocity jets for penetration. During jet formation, the liner collapses and converges at a point source, also known as the virtual origin (VO), along the distance–time plane. The location of the VO must be known to allow the development of penetration analytical models. Here we determined the location of the VO using the ANSYS® Autodyn 2D shaped charge jetting technique. Jetting analysis was conducted for two shaped charges of 18 and 32 mm diameter. The explosive and casing were represented by Eulerian two-dimensional finite difference grids, whereas the liner was modelled using a shell formulation. The summary/history of the jetting analysis was used to determine the VO position in the shaped charges. Interpolating the point of intersection on the liner between the jet velocity (U-Jet) and the cumulative jet mass revealed the location of the VO at a distance equivalent to approximately two-thirds of the inner cone diameter of the shaped charges, in agreement with earlier studies based on different methods. Validation of this technique using the DiPersio, Simon and Merendino (DSM) model based on the Allison-Vitalli equation also showed good agreement with the numerical results.

Output and () correction factors measured and calculated in very small circular fields for microDiamond and EFD-3G detectors

The purpose of this work was to obtain factors for microDiamond and EFD-3G detectors in very small (less than 5 mm) circular fields. We also investigated the impact of possible variations in microDiamond detector design schematics on the calculated factors. Output factors (OF’s) of 6 MV beams from TrueBeam linac collimated with 1.27–40 mm diameter cones were measured with EBT3 films, microDiamond and EFD-3G detectors as well as calculated (in water) using Monte Carlo (MC) methods. Based on EBT3 measurements and MC calculations factors were derived for these detectors. MC calculations were performed for microDiamond detector in parallel and perpendicular orientations relative to the beam axis. Furthermore, factors were calculated for two microDiamond detector models, differing by the presence or absence of metallic pins. The measured OFs agreed within 2.4% for fields ⩾10 mm. For the cones of 1.27, 2.46, and 3.77 mm maximum differences were 17.9%, 1.8% and 9.0%, respectively. MC calculated output factors in water agreed with those obtained using EBT3 film within 2.2% for all fields. MC calculated factors for microDiamond detector in fields ⩾10 mm ranged within 0.975–1.020 for perpendicular and parallel orientations. MicroDiamond detector factors calculated for the 1.27, 2.46 and 3.77 mm fields were 1.974, 1.139 and 0.982 with detector in parallel orientation, and these factors were 1.150, 0.925 and 0.914 in perpendicular orientation. Including metallic pins in the microDiamond model had little effect on calculated factors. EBT3 and MC obtained factors agreed within 3.7% for fields of ⩾3.77 mm and within 5.9% for smaller cones. Including metallic pins in the detector model had no effect on calculated factors. Our results show that microDiamond and EFD-3G detectors can be used in very small (1.27–3.77 mm) fields once corrections determined in this work are applied. Expected uncertainty of such measurements will be in the range of 8%–2.5%.

Dosimetric characterization of a 5 mm diameter BrainLab cone for radiosurgery

Purpose. A dosimetric characterization of a 5 mm diameter cone is presented. PDD curves, dose profiles (OAR) and output factors (Scp) were measured utilizing different detectors. Scp values were obtained using distinct methodologies and they were compared to the new gold standard established by TRS-483 IAEA (2017). Methods. A procedure to align the detector axis of motion and the central axis for PDD determination is described. Four ionization chambers (PTW Farmer 30013, PTW Pin Point 31014, IBA CC01 and IBA CC04), a stereotactic diode (IBA SFD), EBT3 radiochromic film and TLD-600 Micro Cubes were used. For Scp determination five methodologies were considered: direct measurement method (DMM), intermediate field size method (IFSM), Monte Carlo correction factor method (CFM), BrainLab recommended method (BLM) and scanning chamber method (SCM), described by Fan et al (2009 Med. Phys. 36 5292–5300). SFD results were compared to Monte Carlo simulations. Results. PDD curves obtained satisfactorily agree (p < 6.4 · 10−3). The best results for OARs were obtained using high spatial resolution devices, namely EBT3 and SFD diode. A 0.666 value was obtained for Scp as of an average of SFD and CC01 detector results utilizing TRS-483 new methodology. Differences between both results were less than 0.5%, showing how robust the new methodology is. SCM, BLM and EBT3 measurement achieved the most similar results with respect to TRS-483 obtained result (discrepancies of 1.7%, 0.1% and 3.7%, respectively). Besides, Monte Carlo result obtained (0.673) perfectly agrees with these methods results. Conclusions. A multidetector study was performed to obtain the main dosimetric functions to characterize a 5 mm radiosurgery cone. The use of ion chambers is not encouraged for OAR determination because of the important volume averaging effect, higher penumbras and steeper profile fall off nearby the maximum. Utilizing TRS-483 methodology we obtained a value of 0.666. SCM, BLM and EBT3 measurement are reliable procedures to obtain Scp values for very narrow beams due to their slight difference when compared to the new gold standard result.

Fabrication of radially aligned electrospun nanofibers in a three-dimensional conical shape

Abstract This paper reports on the rapid fabrication of radially-aligned, three-dimensional conical structures by electrospinning. Three different polymers, Polyvinylpyrrolidone, Polystyrene and Polyacrylonitrile were used to electrospin the cones. These cone structures are spreading out from a vertical conductive pillar, which can be arbitrarily placed on specific part of the collector. The lower part of the cone is clearly defined on the collector, and the cone has a relatively uniform radius around the pillar. The cones are constituted of fibers that are radially aligned towards the top of the pillar, but there is no apex and the fibers fall flat on the top of the pillar surface. A parametric study has been performed to investigate the effects of the pillar morphology (height and thickness) and the electrospinning parameters (applied voltage and working distance) on the overall shape and size of the cone structure, as well as the fiber alignment. The pillar morphology influences directly the cone diameter and height. The electrospinning parameters have little effect on the cone structure. The formation mechanism has been identified to be related to the shape of the electric field, which has been systematically simulated to understand the effect of the electric field lines on the final dimensions of the cone structure.

Modeling surface fuels moisture content in Pinus brutia stands

Fuel moisture content is an important variable for forest fires because it affects fuel ignition and fire behavior. In order to accurately predict fuel ignition potential, fuel moisture content must be assessed by evaluating fire spread, fireline intensity and fuel consumption. Our objective here is to model moisture content of surface fuels in normally stocked Calabrian pine (Pinus brutia Ten.) stands in relation to weather conditions, namely temperature, relative humidity, and wind speed in the Mugla province of Turkey. All surface fuels were categorized according to diameter classes and fuel types. Six fuel categories were defined: these were 0–0.3, 0.3–0.6, and 0.6–1 cm diameter classes, and cone, surface litter, and duff. Plastic containers 15 × 20 cm in size with 1 × 1 mm mesh size were used. Samples were taken from 09:00 to 19:00 h and weighed every 2 h with 0.01 g precision for 10 days in August. At the end of the study, samples were taken to the laboratory, oven-dried at 105 °C for 24 h and weighed to obtain fuel-moisture contents. Weather measurements were taken from a fully automated weather station set up at the study site prior to the study. Correlation and regression analyses were carried out and models were developed to predict fuel moisture contents for desorption and adsorption phase for each fuel type categories. Practical fuel moisture prediction models were developed for dry period. Models were developed that performed well with reasonable accuracy, explaining up to 92 and 95.6% of the variability in fuel-moisture contents for desorption and adsorption phases, respectively. Validation of the models were conducted using an independent data set and known fuel moisture prediction models. The predictive power of the models was satisfactory with mean absolute error values being 1.48 and 1.02 for desorption and adsorption as compared to the 2.05 and 1.60 values for the Van Wagner’s hourly litter moisture content prediction model. Results obtained in this study will be invaluable for fire management planning and modeling.

Effect of thinning intensity on tree growth and temporal variation of seed and cone production in a Pinus koraiensis plantation

Thinning of Korean pine (Pinus koraiensis Sieb. et Zucc.) is used to facilitate timber and cone production. The present study in Northeast China investigated the effects of thinning intensity on individual tree growth, temporal variation in cone yield, and seed quality in Korean pine plantation. In 2005, five thinning intensity levels (none, extreme, heavy, moderate and light) were set in 15 permanent plots in a 32-year-old Korean pine plantation at Mengjiagang Forest Farm, Jiamusi City, Heilongjiang Province. We recorded tree growth and seed cone production from 2013 to 2016, i.e., from 8 to 11 years after thinning. Except for height growth, thinning increased tree growth (diameter at breast height and crown size) and improved cone yield. The extreme thinning treatment (to 300 trees per hectare) resulted in the largest tree diameter, tree volume, crown size and 4-year cone production per tree. The highest cone yield per tree in the mast year (2014) was observed when stands were thinned to 500 trees per hectare (heavy thinning). Although the best cone and seed quality and the largest cone and seed mass per tree were recorded in the heavily thinned stand, no significant differences were found between heavy and moderate thinning stands (750 trees per hectare). At the stand level, the moderately thinned stand had the highest basal area, stock volume and seed cone production per stand. Our results suggest that thinning to 750 trees per hectare will improve timber and cone productivity in 40-year-old P. koraiensis stands.

EP-1795: Scp measurement of a 5 mm diameter cone using a scanning chamber method

EP-1795: Scp measurement of a 5 mm diameter cone using a scanning chamber method