Base Plane Research Articles

Role of the tangential electric field component to the terahertz jet and hook formation by dielectric cube and sphere

The mechanism of formation of a terahertz jet by a dielectric cuboid and a sphere surrounded by ideally conducting screens is considered. The maximum screen influence is observed when the screen is located near the alight cuboid base. The screen influence eases when the screen is shifting along the dielectric object. Power flux density localization area is almost completely shifted inside the object when the screen is situated in the center. The minimum influence is observed when screen placed in the shadow plane of the cuboid base. This effect caused by the screen influence on electric field component tangential to the side edges and thus on the power flux directed to the central axis of the object. The screen influence on the terahertz jet in spherical object has been compared. Value of the power flux density after passing the object is higher in a cuboid, but the focusing characteristics are better (appearing on shorter distances) in a sphere.

A fast and precise three-dimensional measurement system based on multiple parallel line lasers

This paper conducts a trade-off between efficiency and accuracy of three-dimensional (3D) shape measurement based on the triangulation principle, and introduces a flying and precise 3D shape measurement method based on multiple parallel line lasers. Firstly, we establish the measurement model of the multiple parallel line lasers system, and introduce the concept that multiple base planes can help to deduce the unified formula of the measurement system and are used in simplifying the process of the calibration. Then, the constraint of the line spatial frequency, which maximizes the measurement efficiency while ensuring accuracy, is determined according to the height distribution of the object. Secondly, the simulation analyzing the variation of the systemic resolution quantitatively under the circumstance of a set of specific parameters is performed, which provides a fundamental thesis for option of the four system parameters. Thirdly, for the application of the precision measurement in the industrial field, additional profiles are acquired to improve the lateral resolution by applying a motor to scan the 3D surface. Finally, compared with the line laser, the experimental study shows that the present method of obtaining 41220 points per frame improves the measurement efficiency. Furthermore, the accuracy and the process of the calibration are advanced in comparison with the existing multiple-line laser and the structured light makes an accuracy better than 0.22 mm at a distance of 956.02 mm.

Basal Plane Bending of Homoepitaxial MPCVD Single-Crystal Diamond.

We report herein high-resolution X-ray diffraction measurements of basal plane bending of homoepitaxial single-crystal diamond (SCD). We define SCD (100) as the base plane. The results revealed that growth parameters such as temperature, growth time, and basal plane bending of the substrate all affect the basal plane bending of SCD. First, the basal plane bending of SCD depends mainly on the substrate and becomes severe with increasing basal plane bending of the substrate. The SCD growth experiments show that the basal plane bending increases with elevated growth temperature and increased growth time. Finally, to understand the mechanism, we investigated the substrate-surface temperature distribution as a function of basal plane bending of SCD fabricated by chemical vapor deposition (CVD). This allowed us to propose a model and understand the origin of basal plane bending. The results indicate that an uneven temperature distribution on the substrate surface is the main cause of the base-plane bending of CVD diamond.

A Versatile Gripper for Cloth Manipulation

Cloth manipulation has been mostly advancing in perception and modeling methods for cloth state estimation and grasping point detection. In comparison, less attention has been put on end-effector design. Indeed, most implementations use a parallel gripper that can only perform pinch grasps. Instead, a more versatile set of possible grasp types could ease many tasks by providing more support to certain parts of the object, as well as make feasible tasks that become very complex when executed with only pinch grasps. We present a versatile gripper design which, besides the common open-close thumb+finger(s) feature, has a couple of reconfiguration degrees of freedom that offer, first, a wide base plane to provide support and second, variable friction surface on the thumb tip. Our gripper can execute a versatile set of grasps that ease some complex tasks such as pick and place folded clothes or fold in the air. In addition, the variable friction mechanism enables a more robust pinch-and-slide manipulation to trace cloth edges. Our evaluation shows the gripper potential to execute a wide variety of cloth manipulation tasks.

The Valuation of Thinning Efectivity Based on Increment Respond of Natural Forest Log Over Area

Efforts to increase the natural forest productivity was conducted using several ways one of which is through thinning but the effectiveness is not well known yet. The research aims to evaluate the effectiveness of the application of thinning techniques to logged-over natural forests based on the response of the stand increment. The study design was an 11-year-old logged-over natural forest stand that was carried out systematic thinning, thinning based on built trees and without treatment with a total area of 24 ha. Data collection is done by census inventory of trees with limit diameter of 10 cm per 2 years periodically. Stand conditions in the research plot varied in value range of density (419-510 stems ha-1) and the base plane (22.66-28.20 m2.ha-1) which were not too wide. The results of the calculation of the base plan of the stand shows that systematic thinning yields a larger stand increment (0.78-1.95 m2.ha-1.2th-1) compared to thinning based on built trees and without treatment. Thinning gives more responsive results for the Dipterocarp species group (the increment value is almost twice to normal) compared to non Dipterocarp. Based on the regression analysis, function of time period has correlation between 25-33% to the basal area increment. A systematic thinning technique approach that is more appropriate for increasing stand productivity.

Dynamic Response of Rock Containing Regular Sawteeth Joints under Various Loading Rates and Angles of Application

Intact rock-like specimens and specimens that include a single planar joint or triangular sawteeth joint at various angles are prepared for split Hopkinson pressure bar (SHPB) testing at loading rates of 303.1–5233.6 GPa/s. Only results that are associated with an error (eε) of less than 20.0% are utilized in subsequent analyses. The effects of the loading rate and angle of the load applied to various joint patterns on the failure type and dynamic peak stresses/strength of the specimens are investigated. Experimental results demonstrate that failure of each specimen can be classified into the following four types, Type A: integrated with or without tiny flake-off, Type B: slide failure, Type C: fracture failure, and Type D: crushing failure. The results of statistical analysis of variance (ANOVA) indicate that the loading rate, the angles of the base plane (β), and the asperity (α) of the sawteeth joint of the specimen all affect its dynamic peak stress when fracture failure occurs. The loading rate and β are important when the slide failure occurs, and the loading rate is the sole factor that significantly influences its dynamic peak stress when the specimen is crushed to failure. The dynamic peak stress of the specimen increases with the loading rate, while the rate of increase gradually decreases. The β and α of a jointed specimen affect the location of stress concentration during loading, further influencing the dynamic peak stress of such a specimen under slide and fracture failure. When the loading rate is high and the specimen is crushed to failure, the influences of β and α disappear, and the increase of loading rate reduces the efficiency of raising the dynamic peak stress.

Raman tensor of layered black arsenic

AbstractDue to the similar atom arrangement with black phosphorus, black arsenic also has obvious Raman anisotropy at both the base and cross planes. However, the polarization characteristics of black arsenic have been rarely reported so far with most relevant studies devoted to the base plane. Here, to compensate for the blank of the anisotropy in cross plane, we implemented a systematical angle‐resolved polarized Raman measurement on both planes of layered black arsenic and observed that the Raman intensity ratios (Ixx : Iyy : Izz) of optical phonons and modes along different axes are 1:4.8:2.76 and 6.9:1:5.7, respectively. Based on the definition of Raman intensity, we abstracted integral Raman tensors of black arsenic. In addition, according to density functional theory, it can be affirmed that the Raman anisotropy of Ag mode is sourced from the anisotropy of differential polarizability along different crystal axes.

Disk-Shaped Cobalt Nanocrystals as Fischer\u2013Tropsch Synthesis Catalysts Under Industrially Relevant Conditions

Colloidal synthesis of metal nanocrystals (NC) offers control over size, crystal structure and shape of nanoparticles, making it a promising method to synthesize model catalysts to investigate structure-performance relationships. Here, we investigated the synthesis of disk-shaped Co-NC, their deposition on a support and performance in the Fischer–Tropsch (FT) synthesis under industrially relevant conditions. From the NC synthesis, either spheres only or a mixture of disk-shaped and spherical Co-NC was obtained. The disks had an average diameter of 15 nm, a thickness of 4 nm and consisted of hcp Co exposing (0001) on the base planes. The spheres were 11 nm on average and consisted of ε-Co. After mild oxidation, the CoO-NC were deposited on SiO2 with numerically 66% of the NC being disk-shaped. After reduction, the catalyst with spherical plus disk-shaped Co-NC had 50% lower intrinsic activity for FT synthesis (20 bar, 220 °C, H2/CO = 2 v/v) than the catalyst with spherical NC only, while C5+-selectivity was similar. Surprisingly, the Co-NC morphology was unchanged after catalysis. Using XPS it was established that nitrogen-containing ligands were largely removed and in situ XRD revealed that both catalysts consisted of 65% hcp Co and 21 or 32% fcc Co during FT. Furthermore, 3–5 nm polycrystalline domains were observed. Through exclusion of several phenomena, we tentatively conclude that the high fraction of (0001) facets in disk-shaped Co-NC decrease FT activity and, although very challenging to pursue, that metal nanoparticle shape effects can be studied at industrially relevant conditions.

Testing the limiting coefficient of friction with an adjustable 3-V kinematic coupling

A 3-V kinematic coupling with adjustable vee angles, ranging from 25° to 80° inclination from the base plane, was designed and built to test the limiting coefficient of friction (CoF), which is a measure of the coupling's ability to reach center where all six constraints are engaged. For instance, the vee angles may be optimized by maximizing the limiting CoF to give more margin over the real CoF between contacting surfaces. Although, if the real CoF is too high, that is, higher than the limiting case, the coupling may fail to reach a stable center position. For this experiment, the coupling was configured over a wide-ranging combination of vee angles and several loading conditions for four different surface conditions. The changes in configuration and/or loading condition were made in a logical manner to map out the boundary of incipient sliding between sliding and non-sliding outcomes for a given surface condition. Three of four surface conditions were very clean, either bare 440C stainless steel, thin dense chromium plating, or the same with a proprietary polymer lubricant. The CoF for clean surfaces was too high at about 0.4–0.6 for the coupling to center except for the most favorable sliding direction for which the coupling was being tested. The fourth surface condition was lubricated with vacuum grease and wiped with a clean-room cloth. This lowered the CoF to a point <0.2 where only the least favorable sliding direction could be made non-sliding. An equilibrium equation was developed for this coupling including all the variable parameters under test. Solving it for the limiting CoF for each test configuration successfully resolved the outcomes over the wide-ranging parameter space. This work supports the method used to calculate the limiting CoF and the underlying assumptions that friction forces are directed opposite to local sliding directions and proportional to the contact normal forces.

Introducing a new method for classifying skull shape abnormalities related to craniosynostosis

We present a novel technique for classification of skull deformities due to most common craniosynostosis. We included 5 children of every group of the common craniosynostoses (scaphocephaly, brachycephaly, trigonocephaly, and right- and left-sided anterior plagiocephaly) and additionally 5 controls. Our outline-based classification method is described, using the software programs OsiriX, MeVisLab, and Matlab. These programs were used to identify chosen landmarks (porion and exocanthion), create a base plane and a plane at 4 cm, segment outlines, and plot resulting graphs. We measured repeatability and reproducibility, and mean curves of groups were analyzed. All raters achieved excellent intraclass correlation scores (0.994–1.000) and interclass correlation scores (0.989–1.000) for identifying the external landmarks. Controls, scaphocephaly, trigonocephaly, and brachycephaly all have the peak of the forehead in the middle of the curve (180°). In contrary, in anterior plagiocephaly, the peak is shifted (to the left of graph in right-sided and vice versa). Additionally, controls, scaphocephaly, and trigonocephaly have a high peak of the forehead; scaphocephaly has the lowest troughs; in brachycephaly, the width/frontal peak ratio has the highest value with a low frontal peak.Conclusion: We introduced a preliminary study showing an objective and reproducible methodology using CT scans for the analysis of craniosynostosis and potential application of our method to 3D photogrammetry.What is Known:• Diagnosis of craniosynostosis is relatively simple; however, classification of craniosynostosis is difficult and current techniques are not widely applicable.What is New:• We introduce a novel technique for classification of skull deformities due to craniosynostosis, an objective and reproducible methodology using CT scans resulting in characteristic curves. The method is applicable to all 3D-surface rendering techniques.• Using external landmarks and curve analysis, specific and characteristic curves for every type of craniosynostosis related to the specific skull deformities are found.

Oxidation-enhanced Si self-diffusion in isotopically modulated silicon nanopillars

Silicon (Si) self-diffusivity in a Si nanopillar under dry oxidation was quantitatively evaluated by atom probe tomography of Si isotope heterostructure interfaces. Dry oxidation of a nanopillar with 200 nm diameter at 920 °C for 4 h revealed that the Si self-diffusivity was the same as the one measured for the standard planar oxidation despite the fact that the diffusion region probed in the pillar was surrounded by approximately seven times more oxidation interface areas than the simple planar oxidation case. This finding can be understood by considering the large diffusion length of ∼300 μm of the interstitials for our thermal oxidation condition. The excess interstitials injected by the pillar oxidation as well as those injected by the oxidation of the base (100) plane can easily diffuse through the sample, including interiors of the pillars, making the concentration of the excess interstitials practically equal to those injected for the (100) planar oxidation case.

Real-time rendering of layered materials with anisotropic normal distributions

This paper proposes a lightweight bidirectional scattering distribution function (BSDF) model for layered materials with anisotropic reflection and refraction properties. In our method, each layer of the materials can be described by a microfacet BSDF using an anisotropic normal distribution function (NDF). Furthermore, the NDFs of layers can be defined on tangent vector fields, which differ from layer to layer. Our method is based on a previous study in which isotropic BSDFs are approximated by projecting them onto base planes. However, the adequateness of this previous work has not been well investigated for anisotropic BSDFs. In this paper, we demonstrate that the projection is also applicable to anisotropic BSDFs and that the BSDFs are approximated by elliptical distributions using covariance matrices.

Easy coordinate geometry indexes, τ4 and τ5 and HSA study for unsymmetrical Pd(II), Fe(II), Zn(II), Mn(II), Cu(II) and VO(IV) complexes of a tetradentate ligand: Synthesis, characterization, properties, and antioxidant activities

In this study, versatile multifunctional Schiff base derivative and its metal complexes were synthesized and characterized by 1H, 13C NMR, UV–vis, IR, CHN analysis, Mass spectra, m.p. and X-ray diffraction. The tetradentate Schiff base H2L was synthesized using a microwave-assisted method. Metal complexes [M = Pd (1), Zn (2), Cu (3), Fe (4), Ni (5) Mn (6) and V(O) (7)] were prepared using mild conditions. Their antioxidant activities were assessed by four different methods (DPPH, FTC, HRSA, and H2O2 SA). The antioxidant results revealed that these compounds have moderate to good activities against the BHA which was used as a standard or a positive control. The crystal and molecular structures of H2L, 1, 2 and 7 have been determined by X-ray diffraction on single crystals with Hirshfeld surfaces and fingerprint plots analysis facilitating a comparison of intermolecular interaction. H2L possesses intra-molecular hydrogen bonds. In the complexes, the tetra dentate Schiff base ligands (ONNO) forms a heterocyclic base plane of a distorted square-pyramidal coordination geometry in 1, 2 and 7. Interestingly, only the enol-imine tautomeric form was confirmed by various techniques as an EE isomer. Geometric parameter for four and five-coordinate complexes, τ4 and τ4 for quantitatively evaluating the geometry of the complexes are presented.

Enhanced electrochemical hydrogen evolution performance of WS2 nanosheets by Te doping

Hydrogen evolution reaction (HER) activities of WS2 can be improved by doping exotic atom to increase active sites on base plane and narrow the bandgap. However, most of these catalysts of exotic atom doped WS2 are composed of semiconductor and the electronegativity between atoms is similar, which do harm to tuning bandgap with a wide range and decreasing the value of free Gibbs energy (ΔGH) for hydrogen adsorption. Given that Te can tune bandgap with a wide range and the electronegativity between S and Te differ greatly, a vertically arranged WS2 nanoelectrode is prepared by doping Te on WS2. According to experimental studies and the density functional theory calculations (DFT), the bandgap of WS2 nanosheets is successfully narrowed after doping Te. This lowers the Schottky barrier which benefits the transfer of charges and improves electrocatalytic performance in turn. Meanwhile, the presence of Te atoms with much lower electronegativity than S increases the electron density of the adjacent region, thereby the S edges of basal plane around Te atoms and hollow sites of WS2 nanosheet become active to drive HER, which has been verified by the reduced ΔGH of S edges of basal plane from 2.27 to 2.08 eV and hollow sites from 2.28 to 1.85 eV after the doping in DFT. Te-doped WS2 nanosheets used as excellent HER catalysts with an overpotential of 213 mV to drive a current density of 10 mA/cm2, a small Tafel slope of 94 mV/dec, along with a superior stability in acid media.

Модель динамики колесной машины для комплекса натурно-математического моделирования

Introduction. The use of the method of full-scale-mathematical modeling in “real time” opens up wide opportunities associated with the analysis of the modes of operation of the “man – vehicle – environment” system, as well as the study of the loading of units and assemblies of vehicles. The existing research complexes of full-scale mathematical modeling are suitable for obtaining most of the indicators usually determined by full-scale tests. The difference lies in the ability to fully control the course of virtual testing, recording any parameters of the vehicle movement, taking into account the “human factor”, as well as complete safety of the experiment. Purpose of research. The purpose of this work is to create a mathematical model of the dynam-ics of a wheeled vehicle, suitable for use in such a complex of full-scale mathematical modeling and assessment of the load of transmission units in conditions close to real operation. Methodology and methods. The proposed model is based on the existing model of the dynamics of a wheeled vehicle developed at Bauman Moscow State Technical University. Within the framework of the model, the dynamics of a vehicle is described as a plane motion of a rigid body in a horizontal plane. The principle of possible displacements is applied to determine the normal reac-tions of the bearing surface. The interaction of the wheel with the ground in the plane of the support base is described using an approach based on the “friction ellipse” concept. To enable the driver and operator of the full-scale mathematical modeling complex to drive a virtual vehicle in “real time” mode, the mathematical model is supplemented with a control system that communicates between the control parameter set by the driver by pressing the accelerator and brake pedals and the control actions of the vehicle's transmission units, such as: an electric machine, an internal combustion en-gine, a hydrodynamic retarder and a brake system. The article presents a block diagram of the de-veloped control algorithm, as well as approbation of the system's operation in a complex of full-scale mathematical modeling. Results and scientific novelty. A mathematical model of the dynamics of a wheeled vehicle was developed. It opens up wide possibilities for studying the modes of operation of the “driver-vehicle-environment” system in “real time”, using a complex of full-scale mathematical modeling. Practical significance. A mathematical model of the dynamics of a wheeled vehicle was devel-oped. It is supplemented with an algorithm for the distribution of traction / braking torques between the transmission units, which provide a connection between the driver's pressing on the accelerator / brake pedal and the control parameters of each of the units.

A method of determination of average plane of taps of pipes by triangulation method using an anthropomorphic robot

Nowadays there are various manufacture methods of pipe taps. One of the most laborious operations during manufacture is a marking of pipe taps for subsequent machining. Work layout operations are performed using special tool ware and outfit. These operations are performed manually and it leads to the decrease in accuracy and to the increase of laboriousness. The authors suggest the method of determination of the latent base of pipe tap (average plane) using an anthropomorphic robot. The results of research would help to make the virtual calculation of tool position of the anthropomorphic robot for marking and to generate the robot trajectory. Ultimately, such research would also decrease laboriousness and increase accuracy of marking operation. Materials and methods. The authors supposed to use latent base, namely the average plane of the pipe tap as a measuring base. The robot is calibrated from the base plane placement and chooses the shortest circular arc by comparative approach. Therefore, such shortest arc would form the average plane. The authors carry out the determination of the curve line length by the triangulation method using the interferometer. Results. The result of the research is the technology development for determination of latent base in the average plane form. Discussion and conclusion. The proposed method of latent bases determination of pipe tap would allow making the automated system of marking of pipe taps. Moreover, such method would help to reduce time of performing operations as well as to decrease the manufacture laboriousness on the following stage of technological process.

Differentiation between maxillary and malar midface position within the facial profile.

AimsTo define midfacial position differentiating maxillary and zygomatic regions and to evaluate the corresponding cephalometric characteristics discerning midfacial flatness and fullness.Material and MethodsA total of 183 pretreatment lateral cephalometric radiographs of non-growing orthodontic patients (age 25.98 ± 8.43 years) screened at our university orthodontic clinic. The lateral cephalographs of the orthodontic patients were stratified in four groups: flat, normal toward flat, normal toward full, full,according to distances from nasion and sella to points J and G (NJ, SJ, NG and SG). J is the midpoint of the distance connecting orbitale to point A, and G the center of the triangle connecting orbit, key ridge and pterygomaxillary fissure. Statistics included the Kendall tau-b test for best associations among measurements.ResultsAll measurements were statistically significantly different between flat and full groups. The highest associations were between NJ and SJ (τb = 0.71; p < 0.001) and NG and SG (τb = 0.70; p < 0.001). Flat midfaces were characterized by canting of the cranial base and palatal plane, hyperdivergent pattern and maxillary retrognathism. The opposite was true for fuller midfaces.ConclusionMidface skeletal location was assessed differentially in the naso-maxillary and malo-zygomatic structures differentially. Craniofacial characteristics were identified according to this stratification, indicating the potential for application in facial diagnosis and need for testing on 3D cone-beam computed tomography images.

Microstructure, Texture Evolution, and Mechanical Properties of ECAP-Processed ZAT522 Magnesium Alloy

In this work, the high-strength Mg–5Zn–2Al–2Sn (ZAT522, in wt%) Mg alloys was obtained at 220 °C and 130 °C by a two-step equal channel angular pressing (ECAP). For each stage, two passes were used. The results showed a remarkable grain refinement after the first stage of ECAP (A2 samples), leading to a fine-grained structure with average size of 1.40 μm. The additional stage (A4 samples) caused further grain refinement to 1.18 μm, and an ultra-fine grain structure (700 nm) appeared in the precipitate-rich region. The grain refinement mechanism for both samples was discussed in detail. To this end, the original extrusion fiber texture evolved into a new strong texture characterized by the base planes tilted toward the ECAP shear plane, with a higher Schmid factor value of 0.34. Compared with the as-extruded alloy, the yield strength of the A2 samples increased from 180 to 245 MPa, which was mainly attributed to the combined effects of grain boundary strengthening and precipitation strengthening. In the case of A4 samples, the dislocation strengthening resulted in a net increase in yield strength to 335 MPa, while the ductility was significantly reduced.

Thermo-physical properties investigation in relation to deposition orientation for SLM deposited H13 steel

Components produced by additive manufacturing (AM) exhibit a heterogeneous microstructure, hence results in anisotropic mechanical properties. There are very limited studies available on thermo-physical properties variation in relation to the deposition orientation. Variation in these properties may result in an uneven stress distribution. In this work, thermo-physical properties of H13 tool steel fabricated by selective laser melting (SLM) process were experimentally investigated. The effect of three deposition directions (vertical, horizontal and 45° to base plane of build platform) on thermal expansion, thermal diffusivity, specific heat, thermal conductivity and simplified CCT diagram was studied. Additionally, mechanical properties and metallographic studies of the microstructure were carried out together with the porosity evaluation measurements across the specimens.

Novel integration methodology for an inward turning waverider forebody/inlet

In this study, an inward turning waverider forebody/inlet axisymmetric reference flow model with a conical leading-edge shock wave was designed based on the method of characteristics. The design eliminates the lip shock wave at the shoulder point. Based on the reference flow model, a novel integrated design method for an inward turning waverider forebody/inlet is proposed. The streamline tracing method and related technologies were used to generate the integrated configuration in the reference flow model. During the design process, the inward turning inlet was divided into an upper and a lower surface. After the formation of these surfaces, the front external surface and the lip external surface were simultaneously generated. Finally, an integrated configuration was formed with these four generated surfaces and a base plane. An analysis of the formed configuration was carried out using numerical simulation software, which verified the correctness and feasibility of the method. The conclusions drawn from the research indicate that the integrated design method is feasible and effective.