Spherical End Research Articles

Study on Wax Secretion and Wax‐Secreting System of Mulberry Pest Paurocephala sauteri Enderlein (Hemiptera: Psyllidae)

ABSTRACTPaurocephala sauteri Enderlein is one of the most important pests of mulberry trees in the tropical and subtropical regions of China. This species by penetrating the veins on the back of leaves and buds of mulberry trees, nymphs and female adults can secrete wax, these wax accumulated on the mulberry leaves significantly affects photosynthesis and silkworm cultivation. Therefore, this study aimed to understand the wax‐secreting system and characteristics of wax secretion, expecting a potential strategy to control the species population. The main findings were as follows: scanning electron microscopy revealed that the nymphs and female adults secrete wax in long tubes with spherical ends, and male adults secrete honeydew. Additionally, the wax‐secreting system of the nymphs and female adults differ, the nymph owned a bending moon‐shaped wax‐secreting system, the wax‐secreting system first instar nymph consisted of one circle of rectangular, depressed cell, whereas the wax‐secreting system of second to fifth instar nymph made up of one circle of rectangular, depressed cell and one circle of round, depressed cell. There were a certain number of white pores inside of this depressed cell. Wax filaments produced by these pores are converted into a dense, tight and hollow the wax tube. Gas chromatography/mass spectrometer showed that the main constituents of P. sauteri wax are hydrocarbons. The wax tube as a water conservation pool during the P. sauteri developmental process. This physiological feature may be a key point for a potential strategy to control P. sauteri, even other secreting insects.

CONFORMATIONAL STRUCTURE OF POLYAMPHOLYTES AND POLYELECTROLYTES ON THE SURFACE OF A LONGITUDINALLY POLARIZED GOLD SPHEROCYLINDER

Conformational changes in generally neutral polyampholytic, as well as uniformly charged macrochains, polypeptides adsorbed on the surface of a longitudinally polarized gold spherocylinder—a cylindrical nanorod with spherical ends—were studied. An analytical model of the equilibrium structure of adsorbed macrochains on the surface of a polarized spherocylinder is presented, highlighting the entropy and field factors of the radial-angular distribution of link density. In the course of molecular dynamics simulation, the radial distributions of the density of polypeptide atoms in the central cylindrical part of the nanorod, as well as on its terminal hemispheres, were calculated. In addition, the distributions of the linear density of polypeptide atoms along the axis of the nanorod were calculated. A dumbbell-shaped polyampholyte edge was formed on the surface of the polarized nanorod, dense in the extended central cylindrical part and loose at the ends of the nanorod. There was also a shift of the macromolecular edge from the units of a uniformly charged polypeptide to the oppositely charged end of the nanorod, onwhich this polyelectrolyte edge swelled.

Improving the accuracy of milling engravings of dies of large-sized forgings of heavy-duty vehicle parts

The methodic of experiments and construction of a model for control of the geometric accuracy indicators of forgings of massive parts of complex shapes is considered based on an experimental study of the wear of spherical end mills when processing of samples from dies material. The resulting models were used to adjust the tool path. Keywords:milling, die, geometric accuracy, modeling, spherical end mill, wear Safarov-dt@mail.ru, Kpfu.ktomp@yandex.ru

Temperature-Controlled Laser Processing of Shape Memory Wires: Spherical Ends as Connectors for System Integration

Nickel–Titanium-based shape memory alloys have reached a high technological relevance in the medical field and also for actuation/energy conversion. At present, the interest in new actuation solutions is steadily increasing. However, one important challenge for the design of new actuators is the lack of connection and coupling options, which often hinders a reliable system integration. To address this challenge, this study presents a temperature-controlled laser processing approach for the generation of spherical ends on shape memory wires, which allow a relatively simple integration into different types of systems (e.g., printed circuit boards) in a form-fitting manner. For this purpose, an experimental setup with an integrated pyrometer was used to establish spherical ends on thin NiTi wires with a diameter of 0.24 mm. The resulting microstructures and the functional properties were investigated using scanning electron microscopy, thermal analysis, uniaxial tensile testing, actuation fatigue testing, and hardness measurements. The results obtained in the present study indicate that our laser procedure successfully yields reliable connection options for NiTi wires, without harming the functional performance of the material.

Drop damage analysis of automotive high-pressure composite hydrogen storage cylinders

With the world facing an energy crisis today, hydrogen is attracting attention as a renewable and clean energy source.In this paper, a carbon fiber fully wound plastic liner hydrogen storage cylinder (type IV cylinder) was modeled by software. Then the model was subjected to drop simulation, and by changing the drop height, the drop angle and the residual pressure inside the cylinder, the curve and the cloud diagram of the maximum total stress over time as well as the cloud diagram of the positive stress in all directions and the shear stress in all planes of the cylinder were obtained during the drop process. Meanwhile, by comparing the data and images under each working condition, it can be known that the location where the maximum stress appears is always near the spherical end and the pole hole, but the maximum stress is not a single-valued function of the drop height, and it is also related to the drop angle; and the maximum stress as a whole increases with the increase of the residual pressure. At the end of the article, a drop simulation of the conceptual unlined composite high-pressure hydrogen storage cylinder (V-cylinder) is also carried out, and it is found that the maximum stress during the drop is basically equal to that of the lined high-pressure hydrogen storage cylinder, and the liner mainly plays the role of preventing leakage and corrosion, and does not bear the stress loads.

Comparing Spherical End Mills in Terms of Machining Precision

Comparing Spherical End Mills in Terms of Machining Precision

The Effect of Varnishing and Soaking on Formability of the AW-5052-H28 Aluminium Alloy Sheets in Erichsen Cupping Test

This article presents the results of experimental tests on the stretch-forming ability of 0.21-mm-thick AW-5052-H28 aluminium alloy sheets used in the production of pull-off cups. Erichsen test under various tribological conditions (dry friction, lubrication with graphite lubricant) was used to assess the sheet formability. Punches with a various diameter of the spherical end (8 and 20 mm) were used in the tests. The effect of soaking conditions and varnishing variants on the value of Erichsen indices IE and IE11 was investigated. The sheets were soaked for 13 minutes at various temperatures: 185°C, 190°C and 200°C. In test conditions without lubrication, the lowest value of the IE index = 3.3 mm was observed for sheets in as-received state and for samples after soaking. However, the highest values of the Erichsen index in tests without lubrication were measured for varnished samples and repeatedly soaked. The tests conducted under lubrication conditions with graphite grease revealed usually higher values of the IE index compared to testing conditions without the use of grease. The values of the IE11 index were approximately twice lower than the IE indices. Observation of the bulge surface revealed a smooth surface, which means that the material is characterised by a fine-grained microstructure.

Влияние микрогеометрических параметров сферической поверхности ролика на звуковое давление и вибрацию подшипника

In a production environment of JSC UPC Volzhsky it is shown how to increase the vibration discharge of bearings with conical rollers due to the use of rollers with the specified microgeometric parameters of the spherical surface made in the general production flow. The sphere is formed under the combination of rough grinding, finish grinding and final grinding using an assembled abrasive tool consisting of three rolls of various characteristics. It was found that in a bearing, with sequential replacement of rollers, where sphere roughness varies in the range of 0.10 Ra ≤ 0,.20 microns for rollers with roughness Ra ≤ 0,10 microns, the average value of the microgeometric parameters of the roller sphere in bearings (Ra, undulation W, deviation of circularity Δ) decreases by 2,4 – 4,3 times. The impact assessment of bearing rollers set having different parameters of the microgeometry of the spherical roller end on the sound pressure and vibration of the bearing was carried out. It was found that with an increase in the number of rollers with microgeometric parameters of the sphere closer to the lower edge of the tolerance field, the values of the overall vibration level, the vibration level in the third frequency band and the sound pressure level of the bearing improved. A statistical analysis of these parameters was carried out. The significance of the analyzed factors and conditions for increasing the vibration discharge of the bearing while ensuring processing modes within the framework of the current technological process are determined. Correlation and functional relationships between the average values of the microgeometric parameters of rollers spheres in bearings and the parameters of sound pressure and vibration were found.

MODIFICATION OF THE 5-AXIS TOOLPATH TO INCREASE THE TURBINE HUB SURFACE QUALITY

This industrial article focuses on the finishing machining of workpieces made of aluminium alloy EN AW 7075 with a freeform shape, utilizing minimal material stocks. These workpieces are widely used in sectors like aviation and the energy industry. In these sectors, there is a pressing demand for high-quality production in the initial attempt, eliminating the need for subsequent post-processing operations. The reason for this is to save material and reduce production time. The paper, therefore, deals with a method that involves analysing the shape of a spherical end mill in relation to surface roughness and quality, followed by a mathematical recalculation of the tool path. This approach allows to adjust the machining settings during the preparation phase in order to achieve satisfactory surface quality across the entire machined surface. This method was successfully validated during the final surface treatment of the turbine hubs.

A Wall Effects and Means of Controlling the Evolution of Swirling Flows with Vortex Breakdown

This paper investigates numerically the bubble-type vortex breakdown apparition in the case of closed rotating flows of a viscous, axisymmetric, and incompressible fluid. First, a truncated conical/cylindrical cavity of spherical end disks is used to simulate and analyze the vortex structure under rigid surface conditions. The geometric effects of the enclosure are also studied. Vortex breakdown is demonstrated beyond the lower disk rotation rate threshold by introducing the no-slip condition imposed on the upper wall. The objective is to explore ways of controlling the evolution of this physical event by modifying the confinement conditions upstream of the vortex rupture. Particular attention is also paid to the effective kinematic viscosity, thermal diffusivity and geometric control of recirculation zones on the axis of rotation (axial bubble type). The second geometry consists of a spherical annulus formed by two concentric hemispheres in differential rotation under plat-free surface conditions. The results show that rotation of the inner hemisphere induces a vortex bubble on the polar axis. In contrast, the outer hemisphere rotation induces a toroidal vortex on the equator.

Obtaining experimental data for modeling the geometric accuracy of engravings of dies for hot die forging of forging

The results of resistance tests of a spherical end cutter are presented, as a result of which mathematical models of changes in the geometric accuracy parameters and roughness parameters are obtained. Models are used to justify the tool change period and mathematical modeling of the machined surface. Keywords: spherical end mill, testing, durability, quality index, surface roughness Safarov-dt@mail.ru, kondrashovag@mail.ru

Highly sensitive Fabry-Perot acoustic sensor based on optic fiber spherical end surface

This paper presents and experimentally validates a highly sensitive fiber-optic Fabry-Perot interferometer sound sensor based on a fiber-optic spherical structure. The Fabry-Perot interferometer comprises an aluminum foil diaphragm and a fused fiber-optic microsphere end face, both sealed in a structure made of a glass tube. An optical fiber microsphere structure is used for the first time in acoustic sensing. Based on the strong focusing capability of the microsphere, the high coupling efficiency to the reflected beam, and the extensive range of the focused convergent optical field formed, the focused convergent optical fields facilitate the sensing of an extensive range of motion or deformation of the cavity compared to the divergent optical field of a flat fiber end face, i.e., the acoustic signals at more minor sound pressures can also be well sensed, thus compared to a flat fiber end face fiber The acoustic sensor can monitor acoustic signals over a more extensive frequency range and a larger range of acoustic pressure variations, and the output voltage signal is of a larger amplitude at the same acoustic signal, which allows the monitoring of acoustic signals at acoustic frequencies within the hearing range of the human ear. Experimental results show that the sensor shows a flat frequency response in the range of 20 Hz–20 kHz, covering all frequency components of the human ear hearing range, and the signal-to-noise ratio of the proposed acoustic sensor in the range of 20 Hz–20 kHz is greater than that of the flat fiber end-surface based acoustic sensor and the reference electroacoustic sensor, especially The sensor has the advantages of good high sensitivity, excellent linearity, wide planar response range, and simple manufacturing process. It can potentially be used as a highly sensitive, high acoustic quality fiber optic microphone in practical applications.

Biocompatible polymer optical fiber with a strongly scattering spherical end for interstitial photodynamic therapy.

Interstitial photodynamic therapy (I-PDT), which utilizes optical fibers to deliver light for photosensitizer excitation and the elimination of penetration depth limitation, is a promising modality in the treatment of deeply seated tumors or thick tumors. Currently, the excitation domain of the optical fiber is extremely limited, restricting PDT performance. Here, we designed and fabricated a biocompatible polymer optical fiber (POF) with a strongly scattering spherical end (SSSE) for I-PDT applications, achieving an increased excitation domain and consequently excellent in vitro and in vivo therapeutical outcomes. The POF, which was drawn using a simple thermal drawing method, was made of polylactic acid, ensuring its superior biocompatibility. The excitation domains of POFs with different ends, including flat, spherical, conical, and strongly scattering spherical ends, were analyzed and compared. The SSSE was achieved by introducing nanopores into a spherical end, and was further optimized to achieve a large excitation domain with an even intensity distribution. The optimized POF enabled outstanding therapeutic performance of I-PDT in in vitro cancer cell ablation and in vivo anticancer therapy. All of its notable optical features, including low transmission/bending loss, superior biocompatibility, and a large excitation domain with an even intensity distribution, endow the POF with great potential for clinical I-PDT applications.

Synthesis, Characterization, Conformation in Solution, and Thermoresponsiveness of Polymer Brushes of methoxy[oligo (propylene glycol)-block-oligo(ethylene glycol)]methacrylate and N-[3-(dimethylamino)propyl]methacrylamide Obtained via RAFT Polymerization

The thermo- and pH-responsive polymer brushes based on methoxy[oligo(propyleneglycol)8-block-oligo(ethyleneglycol)8]methacrylate with different concentrations of N-[3-(dimethylamino)propyl]methacrylamide (from 0% to 20%) were synthesized via RAFT polymerization. The "grafting-through" approach was used to prepare the low-molar-mass dispersion samples (Mw/Mn ≈ 1.3). Molar masses and hydrodynamic characteristics were obtained using static and dynamic light scattering and viscometry. The solvents used were acetonitrile, DMFA, and water. The molar masses of the prepared samples ranged from 40,000 to 60,000 g·mol-1. The macromolecules of these polymer brushes were modeled using a prolate revolution ellipsoid or a cylinder with spherical ends. In water, micelle-like aggregates were formed. Critical micelle concentrations decreased with the content of N-[3-(dimethylamino)propyl]methacrylamide. Molecular brushes demonstrated thermo- and pH-responsiveness in water-salt solutions. It was shown that at a given molecular mass and at close pH values, the increase in the number of N-[3-(dimethylamino)propyl]methacrylamide units led to an increase in phase separation temperatures.

Polyvalent Glycan Functionalized Quantum Nanorods as Mechanistic Probes for Shape-Selective Multivalent Lectin-Glycan Recognition.

Multivalent lectin-glycan interactions (MLGIs) are widespread in biology and hold the key to many therapeutic applications. However, the underlying structural and biophysical mechanisms for many MLGIs remain poorly understood, limiting our ability to design glycoconjugates to potently target specific MLGIs for therapeutic intervention. Glycosylated nanoparticles have emerged as a powerful biophysical probe for MLGIs, although how nanoparticle shape affects the MLGI molecular mechanisms remains largely unexplored. Herein, we have prepared fluorescent quantum nanorods (QRs), densely coated with α-1,2-manno-biose ligands (QR-DiMan), as multifunctional probes to investigate how scaffold geometry affects the MLGIs of a pair of closely related, tetrameric viral receptors, DC-SIGN and DC-SIGNR. We have previously shown that a DiMan-capped spherical quantum dot (QD-DiMan) gives weak cross-linking interactions with DC-SIGNR but strong simultaneous binding with DC-SIGN. Against the elongated QR-DiMan, DC-SIGN retains similarly strong simultaneous binding of all four binding sites with a single QR-DiMan (apparent K d ≈ 0.5 nM, ∼1.8 million-fold stronger than the corresponding monovalent binding), while DC-SIGNR gives both weak cross-linking and strong individual binding interactions, resulting in a larger binding affinity enhancement than that with QD-DiMan. S/TEM analysis of QR-DiMan-lectin assemblies reveals that DC-SIGNR's different binding modes arise from the different nanosurface curvatures of the QR scaffold. The glycan display at the spherical ends presents too high a steric barrier for DC-SIGNR to bind with all four binding sites; thus, it cross-links between two QR-DiMan to maximize binding multivalency, whereas the more planar character of the cylindrical center allows the glycans to bridge all binding sites in DC-SIGNR. This work thus establishes glycosylated QRs as a powerful biophysical probe for MLGIs not only to provide quantitative binding affinities and binding modes but also to demonstrate the specificity of multivalent lectins in discriminating different glycan displays in solution, dictated by the scaffold curvature.

AERODYNAMICS OF CYLINDRICAL FINITE LENGTH BODIES

Studies were carried out in the test section of a closed-type wind tunnel. This paper presents the results of velocity distribution in the wake behind short cylinders. To study the effect of the relative length of short cylinders on the aerodynamics of the flow in the wake behind the body, the profiles of the mean velocity were measured in various sections behind short cylinders in the median planes coinciding with the cylinder axis and perpendicular to the cylinder axis. The calculation of resistance of transversely and longitudinally streamlined short cylinders is also given. To determine aerodynamic drag, cylinders with spherical and flat ends were used, as was an ellipsoid of revolution for comparison. The drag coefficient of a transversely streamlined ellipsoid of revolution is somewhat less than its value for a short cylinder at the same elongation of the bodies. In a longitudinal flow around a short cylinder with spherical ends and ellipsoids of revolution, the drag coefficients smoothly decrease with an increase in the Reynolds number to some minimum values. Based on the results of aerodynamic studies, the regularities of the flow around finite length cylinders with different ends shapes in a free air flow with longitudinal and transverse flow in a wide range of geometric and operating parameters have been established.

Comparison of spherical end mills on indicators of processing accuracy

Publications on methods for selecting the optimal cutting tool are analyzed. A method is developed for comparative evaluation of cutters based on changes in such quality indicators of processed die surfaces as the roughness parameter of the machined surface, shape deviation, and adjustment dimension. An example of comparing of different tools is considered. Keywords spherical end mill, tests, durability, accuracy, surface roughness index

Get a grip: inward dactyl motions improve efficiency of sideways-walking gait for an amphibious crab-like robot

Crabs are adept at traversing natural terrains that are challenging for mobile robots. Curved dactyls are a characteristic feature that engage terrain in order to resist wave forces in surf zones. Inward gripping motions at the onset of the stance could increase stability. Here, we add inward gripping motions to the foot trajectories of walking gaits to determine the energetic costs and speed for our 12 degree of freedom (DOF) crab-like robot, Sebastian. Specifically, we compared two gaits in which the step size (stance length) was the same, but the swing trajectories were either triangular (to minimize trajectory length) or quadrilateral (in which the leg deliberately oversteps in order to perform a distributed inward grip). The resulting gripping quadrilateral gait significantly outperformed the nongripping triangular gait on diverse terrains (hard linoleum, soft mats, and underwater sand), providing between 15% and 34% energy savings. Using this gait eliminates the advantage of spherical end effectors for slip reduction on hard linoleum, which may lead to a better understanding of how to use crab-like morphology for more efficient locomotion. Finally, we subjected the walking robot to lab-generated waves with a wave height approximately 166% of the dactyl length. Both gaits enabled the robot to walk undisturbed by the waves. Taken together, these results suggest that impact trajectory will be key for future amphibious robots. Future work can provide a deeper understanding of the relationships between dactyls, gaits, and substrates in biology and robots.

Calibration of industrial robots with spherical joint using single wire encoder

Demands for affordable robot calibration are increasing recently due to collaborative robots and virtual manufacturing. This study proposes a method using a single wire encoder as an affordable device. Unlike previous studies focused on compensating errors from wire sagging and fixture itself, this method utilizes the alignment between spherical joint and wire end by finding minimum wire length. After the optimal joint angles #4 and #5 are found by grid search and polynomial least-square regression, closed-loop kinematic chain and linear least square are utilized to find calibration parameters. With 576 datasets, the position error was reduced from 2.43 mm to 0.78 mm.

Disk hopper feeding device for active orientation of cylindrical parts with a pointed end

An improved design of a disk gear hopper feeding device with gripping organs in the form of through sockets for automatic loading of cylindrical parts with a spherical end face into technological assembly machines and lines, including rotor type, is considered. The proposed technical solutions make it possible to ensure high productivity of the hopper feeding device at low circumferential speeds of the disk with gripping organs, which practically eliminates the possibility of damage when loading easily deformable parts or parts with easily damaged coatings.