Cone Top Research Articles

Simulation and Application of Windowing for High-Grade Steel Thick-Wall Casing in Ultradeep Wells: A Case Study of ST102 Well

Windowing processes in ultradeep wells (> 7000 m) with high steel grade (TP155V) and thick-wall (15.83 mm) casing not only face complex underground environments with high temperature and pressure but also have the difficulty of long operation time and high cost. To improve the success rate and operational efficiency, CAE software was used to establish the casing windowing side-drilling simulation model and optimize the windowing milling cone. Field applications were used to further demonstrate the simulation results. The main conclusions are as follows. The simulation shows that the milling shoulder and the outer circle of the cone top are the main working faces in window opening and window repair. The conical milling cone has the largest windowing stress, highest windowing efficiency, and regular shape of the window. A casing with a depth of 7473 m, wall thickness of 15.83 mm, and steel grade TP155V was successfully windowing using six conical milling cone in the ST102 well, taking 51.76 h, and generating 94 kg iron chips in total; the average milling speed was 0.06 m/h; The casing windowing progress can be determined by observing the return state of the cuttings. ST102 well set three records in China for the deepest drilling depth, highest steel grade, and thickest wall thickness.

Research on Calibration Sources for a 35–40 GHz Millimeter-Wave Solar Radio Observation System

The microwave spectra in the optically thin regime provides unique information about the solar corona magnetic field; thus, a millimetre-wave solar radio observation system (35-40 GHz) in the Chashan Observatory is newly established to obtain relevant data. Herein, we design and develop a blackbody calibration source employing a metal cone array and absorbing patch to calibrate the system and obtain accurate solar observation data for analysis and decision-making. The reflectivity of the calibration source is simulated and measured to characterize its emissivity. The reflectivity is obtained by the finite-integration (FIT) method under various fitting conditions, i.e., the thickness of the absorbent patches and aspect ratios of the cone. The temperature gradient of cones is determined by the finite-element method (FEM). A 5×5 array microwave blackbody was developed based on a cone with a low scattering coefficient and excellent temperature uniformity. To reduce the influence of spurious signals, the time-domain gate technique is used to test the reflectivity of the target. The results demonstrate that the emissivity of the blackbody is higher than 0.9995 in the 35-40 GHz band. The temperature difference between the cone top and the cone bottom is 0.20 °C.

Heat transfer in a conical gap using H2O–Cu nanofluid and porous media. Effects of the main physical parameters

Heat transfer around a conical antenna is quantified in this work. Cooling of this active electronic component is ensured by a medium of high porosity saturated by a H2O–Cu nanofluid with a volume fraction varying between 0% and 5%. The ratio between the thermal conductivity of the porous materials and that of the water (base fluid) ranges from 4 to 41.2, the null value corresponding to a heat transfer without porous media (only nanofluid). The conical enclosure's aspect ratio varies in the 0.2–0.6 range, being its base inclined between 0° (horizontal base with cone's top oriented upwards) and 180° range (horizontal base with cone's top oriented downwards). The associated Rayleigh number varies within the 3.32x105-6.74x107 range. Heat transfer by natural convection is quantified for any configuration combining these five parameters and presented via a correlation allowing determination of the average Nusselt number. This study shows that heat transfer increases when the cone is tilted. For a given aspect ratio, the maximum is reached when the cone is vertical with the top pointing down. This observation remains valid in the overall Rayleigh number range. The average Nusselt number enhancement varies between 20 and 70%, according on the considered cavity's aspect ratio. This study complements a recent one restricted to the case of a cone whose horizontal base is located at the bottom, being 0.2 the aspect ratio of the enclosure.

Development of a Vertical Mashing Machine and Specifying its Main Parameters

The paper proves the necessity to create new modernized types of fruit and vegetable processing machines. The paper highlights the importance of such machinery versatility, since each individual type of fruit and vegetable has its own physical characteristics, such as solidity, viscosity, moisture content, fibers, seeds, and grains. (Research purpose) To study the zucchini mashing process performed by the developed vertical mashing unit. (Materials and methods) An improved mashing machine design is proposed: a vertical plant with a conical auger inside and a sieve drum. (Results and discussion) Based on the calculations, the following parameters are specified: the body wall thickness, the cell diameter, the cone and conical auger parameters, as well as the machine operating modes. The sieve drum height is set at 0.8 meters, the diameter is 0.4 meters, the distance between the cone top and the drum is 0.15 meters. A conical auger is made for four working turns. (Conclusions) The minimum number of zucchini seeds (100 pieces) is specified for the subsequent selection of the drum cell diameter. The criteria and delimitations for high-quality zucchini mashing were identified. The diameter of the vertical masher cells was set within the range from 0.0071 to 0.0093 meters.

Micro-Doppler Parameters Extraction of Precession Cone-Shaped Targets Based on Rotating Antenna

Micro-Doppler is regarded as a unique signature of a target with micro-motions. The sophisticated recognition of the cone-shaped targets can be realized through the micro-Doppler effect. However, it is difficult to extract the micro-motion features perpendicular to the radar line of sight (LOS) effectively. In this paper, a micro-Doppler parameters extraction method of the cone-shaped targets is put forward based on the rotating antenna. First, a new radar configuration is proposed, in which an antenna rotates uniformly on a fixed circle, thus producing Doppler frequency shift. Second, the expression of the micro-Doppler frequency shift induced by the precession cone-shaped target is derived. Then, the micro-Doppler curves of point scatterers at the cone top and bottom are separated by the smoothness of the curves, and the empirical mode decomposition (EMD) method is utilized for the detection and estimation of the coning frequency. Finally, the micro-motion components perpendicular to the radar LOS are inverted by the peak of micro-Doppler frequency curve. Simulation results prove the effectiveness and robustness of the proposed method.

Precession Parameter Estimation From Wideband Measurements for 3-D ISAR Imaging of Cone-Shaped Targets

Precession of the cone-shaped warhead is the typical micromotion of ballistic targets, and 3-D inverse synthetic aperture radar (ISAR) imaging of the precession warhead is of great significance for ballistic target identification. This letter proposes a novel method for the precession parameter estimation and the 3-D ISAR imaging of the cone-shaped target. First, the imaging model of the precession cone-shaped target is developed, and the relationship between the radial-range curve on the range–slow-time plane and the precession parameters is derived. Subsequently, the wideband measurements from two-aspect radars are jointly processed to solve the target precession parameters implicitly involved in the radial-range curve of the scatterer at the cone top. Finally, based on the estimation of precession parameters, the 3-D images of the target can be reconstructed, which reveal the structure characteristics and spatial attitude of the target. Simulation results verify the effectiveness of the proposed method.

Spherical volume elements scheme for calculating van der Waals force between irregular particles and rough surfaces

Various models were proposed to calculate the van der Waals (vdW) forces, but they have generally been complicated and time-consuming. In this paper, a spherical volume elements scheme to calculating the vdW force distributions is proposed, on the basis of the infinitesimal dividing modeling scheme. We apply this scheme to calculate the vdW force distributions between sphere and three types of surfaces with different roughness and also to irregular particles (cylinders, circular cone) orientated differently with respect to the surface. The simulation results reveal that the surface with low roughness has the narrowest force distributions. The average force for the circular cone bottom case is 1, 2, 37 times higher than the case of horizontal, vertical cylinder and circular cone top, respectively. The calculated force distributions are good agreement with exist experimental data. By defining the effective zones of both particles and surface, the computational time of the scheme is an order of magnitude faster than the case of considering the whole surface. The proposed model established the effective zone of the particles in contact from a completely new perspective and significantly simplifies the process of force evaluation.

The effect of land use type on butterfly diversity at Masako Forest Reserve, Kisangani, Democratic Republic of Congo

The effect of land use type on butterfly abundance, species richness, and biodiversity was studied at Masako Forest Reserve in Kisangani, Democratic Republic of Congo. The study was conducted in a primary (PF) and secondary forest (SF), fallow (FW), and an agricultural field (AF). Three bait traps were used; each trap had a cylinder consisting of two metal rings of 30.48 cm diameter and 106.68 cm length with a 15.24 cm cone top. The cylinder and top were nylon mosquito netting with a 55.88 cm zipper sewn into the seam of the cylinder to provide access into the trap to remove butterflies. Traps with rotten bananas as baits were placed at three sites in each of the land use type for 24 h. Trapped butterflies were counted, identified, photographed and released. Results showed that land use type significantly affected butterfly species abundance (p=0.0003) and alpha biodiversity (p=0.0001). The fallow had the highest butterfly species abundance and biodiversity. Cymothoe caenis was the most dominant and Acrea lycoa the least abundant species. Butterflies biodiversity indices significantly correlated with longitude (0.58 to 0.79). These results suggested that land use type and geographic coordinates may have an impact on butterflies at Masako Forest Reserve. More studies are needed to better understand the effect of land use type and longitude on butterfly biodiversity. Key words: Butterfly, forest, land use type, species, abundance, biodiversity.

Morphology Transition of ZnO Nanorod Arrays Synthesized by a Two-Step Aqueous Solution Method

ZnO nanorod arrays (ZNAs) with vertically-aligned orientation were obtained by a two-step aqueous solution method. The morphology of the ZnO nanorods was regulated by changing the precursor concentration and the growth time of each step. ZnO nanorods with distinct structures, including flat top, cone top, syringe shape, and nail shape, were obtained. Moreover, based on the X-ray diffraction (XRD) and the transmission electron microscope (TEM) analysis, the possible growth mechanisms of different ZnO nanostructrues were proposed. The room-temperature PL spectra show that the syringe-shaped ZNAs with ultra-sharp tips have high crystalline quality. Our study provides a simple and repeatable method to regulate the morphology of the ZNAs.

Parameter Estimation of the Precessing Cone-Shaped Warhead Based on the Micro-Doppler with Multi-aspect Observations

Micro-motion feature is one of the effective features used for radar target recognition in the middle section of the ballistic curve. The micro-Doppler expressions of the scattering center at the conical point and two sliding scattering centers in the conical bottom are given, firstly. Then by analyzing the micro-Doppler expressions, it is found that only the precession frequency can be estimated from the micro-Doppler expressions, and other parameters can’t be estimated directly. But all precession and geometry parameters can be estimated by decreasing the number of parameters in the micro-Doppler expressions of two sliding scattering centers, which must use two groups of echoes illuminating the same warhead target from the cone top and the cone bottom. Finally, a new method of estimating all precession and geometry parameters is proposed, and it is validated by the simulation analysis.

Combining surface X-ray scattering and ellipsometry for non-destructive characterization of ion beam-induced GaSb surface nanostructures

Producing surfaces textured with a homogeneous pattern of nanoscale structures is increasingly important for fabrication of semiconductor devices. Although techniques exist for imaging surface nanostructures on a local scale, these techniques are often impractical for use over large areas for finding average structural information. The nanostructured surface in this study consists of densely packed cones produced by sputtering a mono-crystalline GaSb substrate with a low-energy unfocused ion beam, yielding self-organized cones that are slightly tilted away from the sample normal. Here, we devise an all-optical non-destructive characterization scheme using Grazing-Incidence Small-Angle X-ray Scattering (GISAXS) and Spectroscopic Mueller Matrix Ellipsometry (MME) for obtaining all main dimensions including average height, lateral spacing and packing motifs, and the cone top and bottom diameters. It is further shown that both MME and GISAXS are sensitive to small tilts of the nanocone axis from the surface normal.

Trapped liquid drop in a microchannel: Multiple stable states

A liquid drop trapped in a microchannel, in which both contact angle (wettability) and opening angle (geometry) can vary with position, is investigated based on the minimization of free energy. The calculus of variation yields the Young-Laplace equation and its further integration leads to the general force balance. The equilibrium position of the trapped drop is determined by the balance between the area-mean capillary force and the area-mean hydrostatic pressure difference. Trapped liquid drops in truncated cones and hyperboloids are studied to elucidate our theory. As the volume of the drop trapped in the hydrophilic cones is increased, four regimes separated by three critical volumes are identified. The drop is either trapped at the narrow end or away from the cone top. The solution at the cone top satisfies the force balance by adjusting the upper contact angle, which is experimentally observed and verified by Surface Evolver (SE) simulations. Multiple stable states can exist in a particular regime. The hyperboloid tube in which the opening angle varies with position is also considered. As the gravitational strength is increased in hydrophilic hyperboloid, four regimes separated by three critical gravitational strengths are identified. The drop is either trapped near the neck or below the neck. Unlike hydrophilic cones, the drop stays near the neck of the hyperboloid due to varying opening angles. Multiple stable states are also observed. For both cone and hyperboloid, hydrophobic cases are studied as well and all theoretical solutions of the force balance agree well with SE simulation outcomes.

Low-Temperature Fabrication of Germanium Nanostructures by Ion Irradiation: Effect of Supplied Particle Species

Germanium (Ge) surfaces were irradiated by argon (Ar+) ions at 600 eV with a simultaneous Ge, Al, or Au supply at room temperature. The surfaces thus ion-irradiated were characterized by densely distributed nanowalls, nanobelts (narrower than the nanowalls in width), and cones tipped with nanoribbons (narrower than the nanobelts in width), depending on the supplied particle species and the supply rate. The higher the melting points of the supplied materials, the narrower the width of the top of the nanostructures. Thus the melting point and the supply rate of the supplied material are the key parameters for controlling the shape and size in the fabrication of ion-induced Ge nanostructures. It was also demonstrated that for nanowalls and nanobelts, a higher particle supply rate yielded wider nanostructures. For many nanoribbon-tipped cones, the width of the nanoribbon increased with distance from the cone top, and hence resulted in a bottleneck structure.

The effect of crown shape on the reflectance of coniferous stands

The Kuusk–Nilson forest reflectance model was used to study the effect of crown shape on the reflectance of Scots pine and Norway spruce stands. In the first part of the study, we examined spruce and pine stands with an age range of 20–100 years and compared their simulated hemispherical–directional reflectance factors (HDRFs) at nadir in red (661 nm), NIR (838 nm) and MIR (1677 nm) when crowns were modeled as ellipsoids or cones. In all the cases, when a stand was modeled with conical crowns, it had a smaller reflectance factor than the same stand with ellipsoidal crowns. To analyze the sensitivity of HDRF on crown shape, in the second part of the study we simulated the angular distributions of HDRF of two pine stands with different leaf area index (LAI) and canopy closure values at 661 nm assuming four different crown shapes (cone, cylinder, ellipsoid, and cylinder bottom, cone top) and separated the components forming the HDRF. Considerable difference in the HDRF between the four crown shapes was observed: The larger the crown volume, the higher the canopy reflectance at similar LAI and canopy closure. A comparison of the two stands revealed that in denser stands (with a higher canopy closure) single scattering from tree crowns was responsible for the difference in HDRF between the different crown shapes, whereas in stands with a smaller canopy closure the single scattering from ground dominated the HDRF. Finally, the role of crown shape for the retrieval of LAI by inversion from remotely sensed data is discussed.

Peculiarities and mechanism of the cone growth under ion bombardment

Cones were grown on a copper surface under simultaneous irradiation by both Ar + ion and seed tungsten atom flows. The cones were photographed in the SEM after certain irradiation dose at different stages of their life cycle. The cones originate as protuberances growing normally to the surface. They are believed to grow due to ion induced surface stresses on the places where concentration of the implanted seed atoms exceeded the solution limit and destroyed the crystal structure. During certain period of irradiation the growing cones had stable shape and constant growth rate — “stable shape stage (SSS)”. The conditions for the existence of SSS are presented. The main causes of the cone growth during SSS are considered to be sputtering and diffusion to the cone top stimulated by ion induced stresses on the cone slopes. Using the suggested approach, specific peculiarities of cone formation are discussed.

Morphometric Relationships of Some Members of the Heterodera a Venae Complex (Nematoda: Heteroderidae)

A detailed morphological and biometrical study was made of eight Spanish, two British and two Swedish populations of the Heterodera avenae complex. Morphometrical data have been statistically evaluated. Monovariate analysis (Student's t test) was applied to measurements of cysts, cone tops, eggs and juveniles, and multivariate analysis (discriminant analysis and two clusters) was applied to measurements of juveniles. Results demonstrated that there are two well differentiated groups within the H. avenae complex. One is represented by British Ha 11, Spanish Sp. 1 and Swedish Sw. 1 populations. This agrees with previous descriptions of H. avenae. The second group, represented by British Ha 23, Spanish Sp. 3 and Swedish Sw. 2, agrees with previous descriptions of British pathotype 3, Gotland race and H. filipjevi. The two groups are well differentiated by size and colour of old cysts and cone top structures. Spanish populations Sp. 1 and Sp. 3 are best differentiated by the measurements, and significant differences have been shown in 25 of the 29 parameters considered, compared with 14 in British and 11 in Swedish populations. The Spanish populations are more similar to the British than to Swedish populations of the same group as shown by the results of Student's t test. The characters useful for differentiating groups in both Spanish and British populations were: length as well as width of cysts, length of body, tail and hyaline region of tail, c and hyaline region of tail/stylet length in juveniles. The measurements of vulva slit length and fenestra size which differentiate H. filipjevi from H. avenae may also differentiate Spanish populations but not British populations.

Identification of Heterodera cysts by terminal and cone top structures

Detailed examination of the cysts of 39 of the 53 described species of Heterodera, a cyst-forming nematode, was undertaken to provide an adequate basis for identification of these species. Taxonomic keys, based on information gained from studies of cone top and terminal areas of the cyst, are presented. Five morphologically distinct groups are recognized based on difference in vulval slit length, fenestral length, underbridge structures, and bullae. Photographs of the structures used to identify each species supplement the keys.

TAXONOMIC VALUE OF THE CONE TOP AND THE UNDERBRIDGE IN THE CYST-FORMING NEMATODES HETERODERA SCHACHTII, H. SCHACHTII VAR. TRIFOLII, AND H. AVENAE (NEMATODA: HETERODERIDAE)

Distinct morphological differences in the cone top and the underbridge of the cysts serve to separate Heterodera schachtii, H. schachtii var. trifolii, and H. avenae. Correlation between cyst volume and fenestral length of H. schachtii cysts was not significant. In H. schachtii the depth of the underbridge was significantly greater than in H. schachtii var. trifolii, but this difference may be of little taxonomic value because of the variation within the two forms.