Estimating Standing Bamboo Culm Density in Three Genera Using the Pilodyn® Wood Tester

In measurements of superconducting thin-film penetration depths, the need for a reference penetration depth has been eliminated by a modification of the direct-coupled SQUID technique. Furthermore, the technique is convenient for accurate measurements of insulator and thin-film resistor thicknesses in superconducting integrated circuits. Measurements of the penetration depths and insulator thicknesses have been obtained on different chips from a few wafers of a single fabrication run. The results indicate for the first time, on a small scale, the degree of chip-to-chip and wafer-to-wafer control presently obtainable for these parameters.

Influence of the Dopant Penetration Depth on the Solar Cell Performance of n-type Interdigitated Back Contact Silicon Solar Cells

Interpreting strength parameters of strain-softening clay from shallow to deep embedment using ball and T-bar penetrometers

A penetration depth (λ) measurement technique, which is based upon the λ-dependence of the propagation velocity of electromagnetic waves in superconducting transmission lines, is refined and used to accurately measure λ's in Pb films containing Au, In, or Bi additions. The results are applied to test two distinct predictions for λ's in London (or type II) superconductors. First, the measured dependence of λ upon low temperature electrical resistivity is compared with the theoretical prediction for a type II superconductor containing a dilute homogeneous impurity concentration. We find that the measured λ's follow this simple prediction reasonably well, irrespective of the species of impurity, with two anticipated exceptions. Namely, deviations occur for pure Pb, which is not a type II superconductor, and for the highest impurity concentration, in which case the Fermi surface may be appreciably distorted from that of pure Pb. Second, the London-theory prediction for the dependence of the effective penetration depth (λ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eff</sup> ) upon film thickness (d), λ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eff</sup> = λ(T) coth d/λ(T), is tested, in a d/λ range in which coth d/λ, is not closely approximated by 1 or λ/d. Separate experiments in which either film thickness or temperature, T, are varied reveal excellent agreement with the above formula. To our knowledge this is the first detailed confirmation of this explicit hyperbolic cotangent dependency.

Downhole shaped charge depth of penetration (DoP) prediction has historically been largely determined by API Section I unstressed concrete performance. As previously reported [1, 2], reliance on unstressed concrete performance is flawed for several reasons and a review of industry models motivated a new approach based on stressed rock experiments. As a result of a multi-year extensive experimental program, shaped charge DoP into stressed rocks is found to decrease exponentially with an empirically determined formation parameter; the ballistic indicator function, FBI. This parameter which combines formation intrinsic properties (UCS, porosity) and extrinsic properties (overburden stress and pore pressure) is described as well as its integration into an improved downhole shaped charge prediction model. The development of the ballistic indicator function required approximately 600 single-shot experiments spanning 4 shaped charges, 10 different rocks (sandstones and carbonates), overburden stresses from 1 ksi to 20 ksi, and pore pressures from zero to 10 ksi. A recommended test program is presented which currently requires as few as 12 single-shot experiments for each charge to determine two charge-dependent parameters: the reference DoP, DoPref, and the exponential coefficient, α0. These two coefficients are sufficient for FBI&amp;lt;25 ksi which represents the majority of reservoirs currently being perforated world-wide. For reservoirs in excess of 25 ksi, DoP approaches a non-zero limit which is charge-dependent, and a preliminary discussion of this limit is included. This model was initially developed based on sandstone targets. A preliminary extension of this model to carbonate targets is also presented. In general, carbonates behave differently than sandstones with less stress dependence and shallower penetration depths.

The aim of this in vitro study was to estimate the penetration depth and fracture resistance of three different sealers and to verify the relationship between the penetration depth and fracture resistance. Sixty single-rooted teeth were selected and root canal preparation was done. After the instrumentation, the teeth were divided into three groups of 20 each. The groups were then obturated with gutta-percha (GP)-AH Plus sealer, Resilon-Real Seal, and propoint-bioceramic sealers, respectively. Ten teeth from each group were sectioned at three different regions (i.e., coronal, middle, and apical thirds of the root canal) and were viewed under a confocal microscope to determine the penetration depth of the sealer. The remaining samples were subjected to fracture resistance under a universal testing machine and the statistical analysis was done by using one-way ANOVA and post hoc Bonferroni tests. Propoint-bioceramic group showed the highest fracture resistance values followed by GP-AH Plus sealer and Resilon-Real seal groups with no significant difference noticed between them. Depth of penetration was greater for GP-AH Plus sealer, propoint-bioceramic, with no significant difference followed by the Resilon-Real seal group. The newer obturating material propoint-bioceramic group showed a greater fracture resistance. No correlation could be established between the depth of sealer penetration and fracture resistance. Fracture resistance of tooth obturated with propoint-bioceramic sealer combination is significantly greater than GP-AH Plus and Resilon-Real seal combination, thereby showing propoint-bioceramic as a promising obturating material.

Hydroxyapatite is an important constituent of natural bone, and possesses excellent biocompatibility and bioactivity, but its brittle nature limits its use for bone tissue engineering. Nanohydroxyapatite nanoHAP has been used in synthesis of biomimetic composites for more than a decade, yet the mechanics of nanoHAP particles is not fully understood. The present work attempts to advance the current understanding of mechanics of hydroxyapatite at nanoscale, by carrying out systematic nanoindentation experiments on nanoHAP and surface modified nanoHAP prepared by in situ mineralization in presence of polyacrylic acid PAAc. Quantitative nanomodulus maps of both modified and unmodified HAP nanoparticles indicate that various surface features of HAP nanoparticles can be probed. Dips in values of elastic moduli across the nanoparticle surfaces in modified nanohydroxyapatite are indicative of composite responses from both polymer and mineral phases PAAc-HAP on the surface. Nanoindentation experiments were performed at 100, 1,000, 3,000, 5,000, and 8,000 N loads, respectively, to obtain the indentation response from both shallow and deep penetration depths. Nanoindentation results at shallow penetration depths are influenced by nanoscale surface roughness of irregular-shaped HAP nanopar- ticles and nonuniform distribution of PAAc in the microstructure. Significant nonbonded interactions between HAP and PAAc, as well as the mechanical properties of individual constituents HAP and PAAc lead to superior nanomechanical properties of surface-modified nanoHAP as compared to unmodified HAP. The overall inelastic nanomechanical response including damage leading to reduced overall elastic modulus is strongly influenced by the nature of the interfaces between the nanoparticles, especially when indent size is much larger than the particle size.

Ichnology of a Paleopolar, River-Dominated, Shallow Marine Deltaic Succession in the Mackellar Sea: The Mackellar Formation (Lower Permian), Central Transantarctic Mountains, Antarctica

Synchrotron X-ray Topography has been shown to be a vital tool for the nondestructive characterization of defects in 4H-SiC crystals [1-2]. Techniques utilizing reflection geometry are particularly useful for discerning defects at different depths below the crystal surface. For example, in studying defects in SiC pin diode structures, which typically comprise a buffer layer homoepitaxially grown on a substrate, with the drift layer grown on top of the buffer layer, it is important to be able to discriminate the depth at which particular defect configurations reside. This is particularly important for the characterization of defects resulting from relaxation processes such as interfacial dislocations and half loop arrays [3]. There are generally two approaches adopted depending of the level of perfection of the crystal. In deformed regions (such as around dislocation cores) the penetration depth is simply determined by photoelectric absorption. In perfect regions it is determined by extinction. Extinction contrast predicts particularly shallow penetration depths in these geometries, whereas kinematical theory predicts much deeper penetration depths. However, even under the kinematical diffraction conditions, the penetration depth calculated theoretically by just considering a dislocation as a single line is much smaller than the value measured experimentally. In our study we compared two models involving different diffracting volumes. In one model, the volume is defined by the misorientation larger than the FWHM of the rocking curve in the vicinity of the dislocation core. In another model, the contrast is naturally formed by simulating the photoelectric absorption profile of the diffraction beam according to the local lattice plane tilt by assuming the dislocation image formation is dominant by orientation contrast. We will present a comparison between measured penetration depths in grazing incidence geometry with these two approaches and develop an optimized model to explain our observations. [1] Muller, G.S., et al., Volume production of high quality SiC substrates and epitaxial layers: Defect trends and device applications. Journal of Crystal Growth, 2012. 352(1): p. 39-42. [2] Dudley, M., et al., Characterization of 100 mm diameter 4H-Silicon carbide crystals with extremely low basal plane dislocation density, Material Science Forum,2001. 65: p. 353-356. [3] Wang, H., Dudley, M., et al., Studies of the Origins of Half-Loop Arrays and Interfacial Dislocations Observed in Homoepitaxial Layers of 4H-SiC. Journal of Electronic Materials, 2015. 44(5): p. 1268-1274

In the installation of an offshore gravity platform, proper anchoring of a skirt system into the seabed is important. The penetration of the skirt system is generally achieved by built-in ballasting system. Because of (1)inherent spatial randomness in soil resistance; (2)uncertainty in the exact location of the installed platform; (3)insufficient cone penetration test (CPT) values over platform base; and (4)calibration error in predicting skirt penetration resistance from CPT values, the average penetration resistance and the resultant unbalanced moment (in maintaining a horizontal platform position) at each depth of penetration cannot be predicted accurately. A probabilistic model is formulated which will predict the statistics of the penetration resistance and unbalanced moment for a given platform and site condition at any depth of skirt penetration. Such information will help in the design of the capacity of the ballast system. The probabilistic model is also extended to cover the case of sloping seabed.

The amount of melting of PML-type starter contacts with current load 4 is investigated; 6.3; 10A. The contact material of the starters used for the production of silver-based serial contacts (СрН-90 and СрМ-0.2+М1) and experimental copper-based contacts is used in the research. The formula for determining the amount (depth) of penetration during a single current switching is given. The electric arc (its burning time) is directly related to electroerosion phenomena (depth of contact penetration). The formula for determining the depth of penetration is obtained by solving the equation of thermal conductivity taking into account the boundary conditions of the II kind and relates the value of the depth of penetration to the energy and thermophysical parameters of the contact material, which is determined by the constituent components of the material. Difficult operating conditions in agriculture and numerous influencing factors complicate the choice of contact material for starters. In order to ensure the operation of devices with specified reliability indicators, their contact details must resist the influence of an electric arc, a chemically and biologically aggressive atmosphere, and mechanical loads. In general, contacts should be characterized by the following physical parameters: stability of contact transient resistance, high specific electrical conductivity, high erosion resistance and corrosion resistance, high arc resistance and resistance to welding, a combination of mechanical strength and high plasticity. It is practically impossible to choose a universal material that would meet all the mentioned requirements, therefore, depending on the functional purpose of the contact node, a compromise decision has to be made. Contacts of starters operating in the area of small and medium currents (and infrequent switching on and off of short-circuit currents) must, first of all, ensure the stability of the transient resistance under the influence of aggressive atmospheric impurities in combination with high arc resistance and resistance to welding. Therefore, in recent years, attempts have been made to replace the contact material Ag-Ni and Ag-CdO (used in PML starters from 25 A and above) with other materials. Transient resistance depends on the actual contact area of the contacts and on the specific resistance of the contact material. The effective area of contact depends on the magnitude of the contact pressure and increases exponentially with its growth until the compressive stress is higher than the yield point of the material. On the other hand, the transient resistance depends on the resistance of the boundary layer, which is determined by its composition (the presence of oxide, sulfide and other films, dust, etc.) and specific electrical resistance. Taking into account the requirements for switching devices of starters suitable for work in the agricultural sector and in order to save precious metals, it is appropriate to develop contact materials in the direction of improving the properties of multi-component composite materials based on copper and refractory compounds. Copper is the closest material to silver in terms of physical and mechanical properties. But its main drawback is that it oxidizes in the air and the oxidation process intensifies as the temperature rises. As a result, insulating films appear on the surface of the copper, which disrupt the operation of the contacts and lead to failures. It is known that copper oxide films are formed even at room temperature and their thickness reaches no more than 5 μm. Such a film protects copper from further oxidation by oxygen. The specific resistance of Cu2O is 10 μΩˑm, but it does not significantly affect the contact resistance of the electrodes, since the film is very thin, so electrons pass through it due to the tunnel effect.

Performance of concrete targets mixed with coarse aggregates against rigid projectile impact

Determination of penetration depths and analysis of strains in single crystals by white beam synchrotron X-ray topography in grazing Bragg-Laue geometries

The assessment of water resources in soil is important in understanding the water cycle in the natural environment and the processes of water exchange between the soil and the atmosphere. The main objective of the study was to assess water resources (in 2010–2013) in the topsoil from satellite (SMOS) and in situ (ground) measurements using the SWEX_PD approach (Soil Water EXtent at Penetration Depth). The SWEX_PD is a result of multiplying soil moisture (SM) and radiation penetration depth (PD) for each pixel derived from the SMOS satellite. The PD, being a manifold of the wavelength λ0 equal to 21 cm, was determined from the weekly SMOS L2 measurement data based on the real and imaginary part of complex dielectric constant. The SWEX_PD data were compared with soil water resources (WR) calculated from the sum of components derived from multiplication of soil moisture (SM) and layer thickness in nine agrometeorological stations located along the eastern border of Poland. Each study site consisted of seven neighbouring Discrete Global Grid pixels (nodes spaced at 15 km) including the central ones with agrometeorological stations. The study area included different types of soils and land covers. The agreement between the water resources obtained from the SWEX_PD and ground measurements (WR) was quantified using classical statistics and Bland–Altman's plots. Calibrated Layer Thickness (CLT = dbias) from 8 to 28 cm was obtained with a low values of bias (close to zero), limits of agreements, and confidence intervals for all the SWEX_PD, depending on the pixel location. The results revealed that the use of the SWEX_PD for assessing soil water resources is the most reliable approach in the study area. Additionally, the data from Bland–Altman plots and the equation proposed in these studies allowed calculation of the Equivalent Layer Thickness (ELT = d_{ei}^{SWEX}), which corresponds to the water resources derived from the SMOS satellite at the same time as (SM) measurements performed in the agrometeorological stations. The ranges of the mean, standard deviation, minimum, maximum, and coefficient of variation (CV) of ELT among all pixels and stations were 8.28–28.7 cm, 3.27–12.66 cm, 3.03–10.87 cm, 19.23–94.97 cm, and 24.72–98.79%, respectively. The ranges of the characteristics depended on environmental conditions and their means were close to the values of the calibrated layer thickness. The impacts of soil texture, organic matter, vegetation, and their interactive effects on the differentiation and agreement of soil water resources obtained from SWEX_PD vs. data from ground measurements in the study area are discussed. Further studies are required to address the impact of the environmental factors to improve the assessment of soil water resources based on satellite SM products (retrievals).

This study introduces a novel phosphate-based packer fluid, designed for use in high-temperature and high-pressure oil and gas wells. The research aims to evaluate the performance of this innovative fluid in comparison with traditional acetate and formate-based fluids. The study highlights the enhanced performance metrics of the phosphate-based fluid, which include a higher density of 114 pcf, moderated pH levels from 13.5 to 10, and a significantly reduced corrosion rate to below 4 mpy, achieved through the addition of diammonium phosphate and potassium vanadate. Moreover, the research presents two machine learning models (an artificial neural network (ANN) and genetic programming (GP)) developed to predict the penetration depth of the phosphate-based fluid. Both models demonstrate high accuracy, with R-square values of 0.9468 and 0.9140, respectively, with the ANN model exhibiting slightly superior performance. The findings of the study indicate that the phosphate-based fluid, free of solubilizers and enhanced with innovative corrosion inhibitors, provides optimal thermal stability, minimal formation damage, and shallow penetration depth, thus representing a significant advancement in well completion technologies. The fluid’s distinctive properties and the predictive models’ high accuracy highlight its suitability for challenging environments, marking a notable progression in well completion technologies.