Cone Length Research Articles

Computational study of the multiphase flow and performance of dense medium cyclones: Effect of body dimensions

This paper presents a numerical study of the gas–liquid–solid flow in 1000 mm dense medium cyclones (DMCs) with different body dimensions, which includes the spigot diameter, cylinder length, cone length and inlet size by means of a computer model which we recently proposed. In this model, mixture multiphase model is used to describe the flow of the dense medium (comprising finely ground magnetite contaminated with non-magnetic material in water) and the air core, where the turbulence is described by the well-established Reynolds Stress Model. The stochastic Lagrangian Particle Tracking method is used to simulate the flow of coal particles. It is found that the spigot size is very sensitive to the performance. The operational head and medium split reporting to overflow, decrease dramatically as the spigot diameter increases. The density differential decreases rapidly, and then passes through a minimum and increases slowly. The long body including cylinder and cone is helpful to particle separation, particularly for fine and heavy particles. The inlet size plays a remarkable role on the performance on DMCs. The operational head, the density differential and the medium split increase dramatically as the inlet size decreases. Both the upward flow and the downward flow become very strong in the DMC with a small inlet when medium feed rate is constant, which results in a very low Ep.

Physical modelling of pressure flushing for desilting of non-cohesive sediment

During pressure flushing of deposited sediments over large dam intakes, a funnel-shaped crater is formed due to considerable shear flow around the opening. Experiments with variable flow depth and discharge were conducted to determine the geometry of the flushing cone for fine, medium and coarse non-cohesive sediments. These sediments increase with increasing discharge and decrease with increasing reservoir depth and sediment particle size. Using the test results, two equations are proposed to estimate scour cone length and volume. While the water depth over the sediments is the most significant parameter in the collapse of sediments above the intake and initial development of the cone, the sensitivity analysis indicated that the intake flow velocity is the most significant parameter in determining the final equilibrium size of the scour cone. The results were compared with a previous study made with a small-scale model to confirm the proposal.

Topografia do cone medular em gatos sem raça definida

Estudou-se a topografia post mortem do cone medular em 30 gatos adultos sem raça definida. Procedeu-se à remoção da pele e da musculatura dorsal da coluna vertebral e expuseram-se a medula espinhal e seus envoltórios, após a secção dos arcos vertebrais. O cone medular foi evidenciado e mensurado. Avaliou-se a sua relação com as vértebras lombares (L), sacrais (S) e caudais (Cd). O cone medular variou de 3,40 a 8,00cm (média=5,08cm). A esqueletopia foi variável, pois em 24 (80%) animais o cone medular iniciou-se na vértebra L6; em quatro (13,3%), na L7; e em dois (6,7%), na L5. Em 12 (40%) animais terminou na vértebra S2; em 10 (33,3%), na S3; em cinco (16,7%), na Cd1; em dois (6,7%), na S1; e em um (3,3%) na Cd2.

Relativistic Energy Pb Projectile Fragmentation with Heavy Target Nuclei

We investigate the fragmentation of 158AGeV 207Pb projectiles with Bi, Pb, Cu and Al targets using CR-39 nuclear track detectors. The exposures were made at SPS-CERN. After the etching, the detectors were scanned using an optical microscope to collect the data of etched cone diameters and lengths. We measured the partial charge-changing cross sections using the data of etched cone lengths. The predicted cross sections are compared to similar measurements reported in literature and their dependences on projectile and target mass are described.

Experimental Investigation of a Minihydrocyclone

AbstractA phase doppler particle analyzer (PDPA) was used to measure the liquid/solid two‐phase flow pattern in a 25 mm minihydrocyclone. The distributions of velocity, concentration, root mean square (RMS) velocities, and especially the average diameter of the particles were evaluated in this work. The measurements showed that in the upper section of the minihydrocyclone the particles accumulated in the outer helical flow near the line of zero velocity value (LZVV), which probably means that the inner helical flow has a more important influence on the separation. Strong turbulence occurred around the air‐core as well as around the zone near the wall. The RMS value indicated that the transformation of the axial flow direction takes place in the lower section of the conical length.

Two new sympatric species of freshwater Gammarus (Crustacea: Amphipoda) from Southern Zagros Region, Iran

Gammarus zagrosensis n. sp. and Gammarus sepidannus n. sp., both from Gammarus pulex–group, are described from Sepidan County, Fars Province. They inhabit mountainous springs and were found co-occuring in some localities. Many clear morphological differences were recognized, including the setation of the second antenna and pereopods, length of antennal gland cone, postero-inferior protruding lobe and postero-distal corner setation in the basis of P6–7, endopodite/exopodite ratios of uropod 3, dorsal elevation of urosomites, and setation of lower distal margin of epimeral plates 2 and 3. Gammarus zagrosensis is distinguished from G. pseudosyriacus by having setae on the distal segments of pereopod 5–7, a less pointed epimeral plate 2, posterior-inferior corner setae, and the longer setae on uropod 3. The closest species to G. sepidannus are G. balutchi and G. lobifer, the most evident differences of which are the eye size, setosity of first antennal peduncles and flagellum of second antenna, length of gland cone, and uropod rami length ratios. Comparison of the head cuticular micro-structures gives more arguments for separating the two new species from each other, as well as from the previously studied, related species.

Effects of conical nozzle configuration on impulse coupling coefficient in repetitively-pulsed laser propulsion

A dimensionless factor was introduced to deduce the analytic expression of impulse coupling coefficient for conical nozzles in the case of spherical symmetry, and a high precision impact pendulum system was used to measure impulse coupling coefficients of 15 conical nozzles with different cone angles and lengths. The expression was corrected according to experimental values. The results indicate that: 1) impulse coupling coefficient increases firstly and then decreases with augment of dimensionless length when cone angle is fixed; 2) impulse coupling coefficient decreases monotonously with augment of cone angle when dimensionless length is fixed; 3) it is of great importance for improving impulse coupling coefficient to increase the rate of laser energy deposition.

Computational fluid dynamics prediction of the air-core in hydrocyclones

The air-core diameter was successfully predicted by large eddy simulation and volume of fluid models. The dynamics of the flow for 75- and 250-mm hydrocyclones was evaluated in 11 cases in which the spigot diameter, conical length, vortex finder diameter, diameter of the hydrocyclone and viscosity of the fluid were changed. FLUENT™ 6.0 code was used to compute the dynamics of the flow. The air-core profiles demonstrated the accuracy of the simulations. A reduction in the spigot increases tangential velocity and hence air-core diameter is increased. An increase in hydrocyclone diameter also increases air-core diameter, while the vortex finder or an increase in fluid viscosity inversely influences it. The vortex finder influences inversely air-core diameter. The increase in viscosity of the fluid reduces air-core diameter. The computational time required to reach the solution increases as the domain size increases. The LES model cannot be used in everyday cases to optimise hydrocyclones, but it is an outstanding tool to study new designs.

Cone-Rod Dependence in the Rat Retina: Variation with the Rate of Rod Damage

To assess the effect of accelerated rod damage on the integrity of cones in the rat retina. Rhodopsin-mutant P23H-3 and Sprague-Dawley (SD) rats were raised in scotopic ambient conditions (12 hours dark, 12 hours 5 lux) and then exposed to photopic conditions (12 hours dark, 12 hours 300 lux). Rods and cones were assessed for cell death, outer segment (OS) morphology, and electroretinogram (ERG) responses. Cones in the P23H-retina were affected rapidly by photopic exposure. Exposure for 2 days caused 50% reductions in LM- and S-cone OS length and cone ERG responses, associated with and preceded by reductions in rod OS length and ERG responses. Although 2 days' exposure increased the rate of rod death, outer nuclear layer thinning was minimal, and no evidence of cone death was detected. In the SD retina, the same photopic exposure had no measurable effects on death rates, OS length, or ERG responses in either rods or cones. Longer (7 days) photopic exposure reduced cone and rod OS length and ERG responses in SD, as well as P23H-3 retinas, but less severely than in the P23H-3 strain. Cones are damaged rapidly in the P23H-3 retina when rod damage is accelerated by raised ambient illumination. This close dependence of cone integrity on rod integrity contrasts with the life-long persistence of cone function in the scotopic reared P23H-3 rat. In humans suffering comparable photoreceptor dystrophies, the maintenance of steady, low ambient light may, by minimizing acute rod damage, optimize the function of surviving cones.

Minimally Invasive Therapy of Cervical Intraepithelial Neoplasia for Fertility Preservation

The aim of this study was to determine the extension of cervical intraepithelial neoplasia grade III (CIN III) into endocervical canal and depth of endocervical crypts involvement by CIN with the regard to patients' age and parity. Correlation between the area of CIN involvement and the extension into endocervical canal was estimated. A total of 218 cervical cone specimens with histologically proven CIN III were included in this study. Extension of CIN into the endocervical canal, depth of involved crypts and ectocervical area affected by CIN were histologically analyzed. The average endocervical crypt involvement was at 1.2 mm of depth. The excision of >4 mm (1.2 mm x 3S.D.) in depth removes >99% of CIN. With the cone length of 15 mm (nulliparous patients) and 18 mm (multiparous patients), no endocervical cone margins were affected with CIN. Since the cone length is the most important determining factor for fertility preservation, the measurement of cervical cone could be essential for future pregnancies.

Effect of cone angle and length of the slot on the performance of feed slot conical air bearing

Externally-pressurised conical air bearings can carry axial as well as radial loads. It is advantageous to develop conical bearing system because of its simple shape, easy fabrication, small space requirement and adjustment of clearances in the assembly. These bearings have been studied for orifice feeding of air which causes dispersion losses resulting in reduced load capacity. Feed slot configuration approximates to a line source and gives good distribution of fluid pressure and reduces the dispersion losses. Various characteristics like load capacities and stiffnesses of an externally pressurised conical air bearing with a feed slot are investigated in this paper. These characteristics are studied to obtain the effect of cone angle and length of the slot on the performance of these bearings.

Resultados obstétricos tras conización. Hospital de León. Período 1999–2007

Objective To determine the obstetric results after conisation at the Leon Hospital (Spain) between 1999 and 2007. Material and method We performed a retrospective cohort study of 338 conisations. Thirty-six women conceived and a total of 46 pregnancies were obtained during the study period. The following variables were analysed: maternal age, obstetric antecedents, smoking, the diagnoses motivating the conisation, final histopathological diagnosis, height of the extirpated cone, conisation-childbirth interval, type of labor, and gestational age and weight of the newborn. Results Of the 30 pregnancies that exceeded 24 weeks, 20% ended preterm. No differences were found when the groups were compared according to smoking. None of the newborns was underweight for gestational age. Conclusions A significant statistical association was observed between conisation and preterm delivery, independently of cone length or the conisation-labor interval. No statistical association was found between low birthweight and conisation.

DESIGN OF A WIDE-ANGLE BICONICAL ANTENNA FOR WIDEBAND COMMUNICATIONS

The wide-angle bicone antenna terminated by a spherical cap is investigated. The antenna radiation patterns have been observed for various values of ka where k represents the phase constant and a represents the conical length. It is seen that for large values of ka the radiation pattern is limited within an angular sector bounded by the cones of the antenna. Next the antenna is optimized for ultra- wideband (UWB) operation through the use of loading techniques. The transient wideband radiated and received responses of the antenna have been observed and the relationship between the wave shapes of the transient fleld and the input pulse have been determined.

The rational homotopy Lie algebra of function spaces

In this paper we fully describe the rational homotopy Lie algebra of any component of a given (free or pointed) function space. Also, we characterize higher order Whitehead products on these spaces. From this, we deduce the existence of H -structures on a given component of a pointed mapping space \mathcal F_*(X,Y;f ) between rational spaces, assuming the cone length of X is smaller than the order of any non trivial generalized Whitehead product in π_*(Y) .

Monogeneans of the grouper Epinephelus tauvina (Perciformes, Serranidae) off Moorea, French Polynesia, with a description of Pseudorhabdosynochus pai n. sp. (Monogenea: Diplectanidae)

Specimens of the greasy grouper Epinephelus tauvina (Forsskål), caught off Moorea, French Polynesia, harboured four species of gill monogeneans. The diplectanid Pseudorhabdosynochus pai n. sp. is characterised by an extremely big male quadriloculate organ (inner length 77 mum, cone length 15, tube length 47), the largest of all members of the genus, and a sclerotised vagina with a very complex structure, including three secondary chambers instead of one as in most species. Pseudorhabdosynochus sp. is a species of the 'cupatus group'; this species is not formally described but various measurements are provided. The ancyrocephalid Haliotrema sp. and the capsalid Benedenia sp. were rare; they are both mentioned but not described. The diplectanid fauna of E. tauvina corresponds to the pattern already found in a clade of grouper species, the members of which often harbour both a species of the 'cupatus group' and another species of Pseudorhabdosynochus Yamaguti, 1958.

Seed source variation and conservation of Pinus wallichiana in India

Pinus wallichiana A.B. Jacks is an important component of the middle and high altitude Himalayan forests having large natural distribution ranging between 260 to 360 N latitude and 690 to 750 E longitudes. It is commonly known as Himalayan blue pine or blue pine, being indigenous to Himalayan Mountain regions and because of its bluish or grayish-green leaves. It is a five needle pine which gained world-wide attention for its resistance to blister rust among white pines. This species has been crossed successfully with other white pines and vigorous hybrids have been obtained. Considerable variation in morphological and anatomical characteristics of needles, cones and seeds in natural stands exists across the natural distribution of the species, especially in mesic and xeric habitats. These variations suggested the differentiation of this species in ecotypes or varieties as reported by various authors. However, the level of genetic diversity was found to be relatively high and the degree of genetic differentiation was low compared to other pines. The wide range of climatic conditions in the natural distribution of this pine is expected to result in high genetic variation within different populations of the species. The study aims to determine the nature and extent of variation present in the populations of the species in respect to cone and seed characteristics across its natural distribution. Seed of 17 seed sources from the states of Uttaranchal and Himachal Pradesh was collected and analyzed for cone characters (fresh weight of cones, cone length, cone width, specific gravity) and seed characters (seed weight, moisture content, germination percent, cotyledon number). Significant variations have been observed in these traits among different seed sources of the species. The cone weight varied from 44.4 to114g and the higher cone weight was recorded at higher altitudes. The germination percent varied from 40 to 85 whereas cotyledon number varied from 7 to12. Seed weight ranged from 35.70 to 69.30g in all seed sources. These variations can be utilized further in identifying the best seed sources in improving the productivity of the species. The genetic variability present in this pine has been conserved in preservation plots demarcated and maintained in its natural ranges of distribution in the country, since the early 19th century.

Geometrical track parameters in the pallasite olivine: Identification of the cosmic ray heavy nuclei

The geometry characteristics of chemically etched tracks in the not annealed olivine crystals from pallasite meteorites are investigated with the search and identification goal of fossil tracks of galactic cosmic ray heavy and superheavy nuclei. The chosen methodology is based on precise measurements of the nucleus track parameters in the course of chemical etching of the olivine crystals. Geometric parameters of individual tracks are traced and measured in course of their step-by-step chemical etching by using a modern high-precision, completely automated facility PAVICOM designed at the Lebedev Physical Institute of Russian Academy of Sciences. A method of the layer-by-layer removal of olivine material is employed, which allows the tracks to be studied over the whole crystal volume under study. It is planned to measure the next main parameters: the cone length and diameters of etched track within the initial, high-energy section of its formation; the total residual range and diameters, corresponding to saturation zone of the primary ionization; and the etching rate along the different parts of tracks, the starting inter-volume olivine crystal point for which were fixed. The preliminary experimental results obtained for 42 tracks, detected and analyzed in the Marjalahti pallasite olivine crystals, are presented.

Investigation on Elliptic-Shaped Flaring Process of Metal Tube with Finite Element Method

In this study, the finite element method was used to investigate the cold elliptic-shaped flaring process of metal tubes with a conical punch from a tube billet. A series of simulations on tube flaring was carried out using the FEM program DEFORM 3D. The influence of process parameters such as tube wall thickness, punch conical length, aspect ratio of elliptic shape, friction factor, punch fillet radius and strength coefficient of the billet material on the critical flaring ratio of the tube were analyzed.

Numerical simulation and optimization of fluid flow in cyclone vortex finder

In this study, a computational fluid dynamics is used to predict and evaluate the effects of vortex finder shape and diameter on cyclones performance and flow field. The Eulerian–Lagrangian computational procedure is used to predict particles tracking in the cyclone. The flow field is calculated using 3D Reynolds-averaged Naveir–Stokes equations. The Reynolds stress transport model (RSTM) is used to simulate the Reynolds stresses. The Newton's second law is used to study the particles trajectory with modeling the drag and gravity forces acting on the particles. The velocity fluctuations are simulated using the discrete random walk (DRW). Four different cylinder-shaped and six cone-shaped vortex finders are simulated for various flow rates of 30, 50 and 70 l/min. The cylinder-shaped vortex finders have different diameters, i.e. 15, 11 and 7 mm, and the cone-shaped vortex finders have different cone lengths, i.e. 10, 25 and 45 mm, with 7 and 15 mm diameters at both ends of the cone. The particles size range is 0.5–3 μm. The details of the flow field are studied in the cyclones and the effects of the different vortex finders are observed. The numerical results are compared with the experimental data and good agreement is observed.

Single-sheet identification method of heavy charged particles using solid state nuclear track detectors

The theoretical and experimental investigations of the penetration of charged particles in matter played a very important role in the development of modern physics. Solid state nuclear track detectors have become one of the most important tools for many branches of science and technology. An attempt has been made to examine the suitability of the single-sheet particle identification technique in CR-39 and CN-85 polycarbonate by plotting track cone length vs. residual range for different heavy ions in these detectors. So, the maximum etchable ranges of heavy ions such as 93Nb, 86Kr and 4He in CR-39 and 4He and 132Xe in CN-85 polycarbonate have been determined. The ranges of these ions in these detectors have also been computed theoretically using the Henke-Benton program. A reasonably good agreement has been observed between the experimentally and theoretically computed values.