Conical Portion Research Articles

Truncated cones from indenting a clamped disk.

When a simply supported thin disk is indented by a centrally applied point force, it buckles out-of-plane to form a shape dominated by two conical portions: a uniform region indenting against the support, interrupted by a smaller elevated portion detached from the support, altogether known as a "developable cone" or d-Cone. If a central circular region of the disk is clamped instead, then the buckling complexion changes markedly: The indenting region is interspersed with several detached and elevated cones, now "truncated," where their number depends on the clamping extent as well as the radius of the circular simple support. Studies of d-Cone kinematics often consider its shape as an analogous vertex, which forms by folding along hinge lines separating triangular facets. We extend this methodology by, first, showing that each truncated cone, or "t-Cone," operates as a pair of connected d-Cone vertices that fold synchronously and that their number, viz. distribution, around the indented disk stems from optimal "packaging" of the folded shape in the annular space between the clamping edge and support; furthermore, because our analysis presumes a geometrically dominant character, it captures the "saturated," i.e., final number of t-Cones, in experiments from a recent study. Our predictions agree rather well.

A new species of Mutinus (Phallaceae, Phallales) from Shandong Province, China

A new species, Mutinus taishanensis (Phallaceae, Phallales, Basidiomycota), was found growing in a forest of Phyllostachys flexuosa and Quercus palustris in Zhulin Temple, Mount Tai Scenic Area (Tai’an City, Shangdong Province, China). It is described as new based on morphological, molecular and ecological evidence. Our phylogenetic analyses based on DNA sequences of the large subunit of nuclear ribosomal DNA (LSU), subunit 6 of ATP synthase (atp6) and the second largest subunit of RNA polymerase II (RPB2) support the inclusion of this new species in the genus Mutinus as it forms an independent clade in the phylogenetic tree. Morphologically, M. taishanensis differs from any known species by the combination of light red to red pseudostipe, red conical fertile portion (covering about 1/4–1/5 of the total length of pseudostipe), and relatively small basidiospores. We present this new species with illustrated morphological description. phylogeny and comparison with morphologically similar or phylogenetically related species.

Estimating the requirements of pressure drop during fluidization-bubbling regimes in fluidized bed with different conical distributors

The pressure drop across the distributor signifies the total pressure drop and ensures desired fluidization in the fluidized bed. This study estimates the pressure drop requirements for 1.2 and 2.05 mm particles utilizing two distinct perforated type conical distributors with 154 and 302 orifices, respectively. The investigation was carried out in a cold flow condition. The pressure drop across the distributor was introduced in this investigation by filling bed material in the conical portion of the distributor. To estimate the bed pressure, a combined pressure drop of the conical distributor with and without bed material was approached. Explicitly, pressure drop requirements for the minimum fluidization and bubbling regimes have been focused on and presented in this work. In view of bed pressure, an attempt has been made to establish a relationship for pressure requirements across distributors. The integration and estimation of pressure drop across distributor with bed material in conical portion could be very beneficial in view of the fluidized bed. As the bed height increased, the pressure increased, but the pressure drop ratio decreased for the selected particles. The distributor features a higher number of orifices that demonstrate lower pressure requirements during fluidization and bubbling regimes. This study emphasizes the desired pressure requirements for the fluidized bed.

A review on the Investigation of Hydrocyclone Performance by shape optimization

A hydrocyclone is a centrifugal classifier that separates particles by size using centrifugal force. Applications for hydrocyclones are incredibly varied. It is used to separate solids from liquids, liquids from liquids, and gases from liquids. It is easy to install and use, simple, inexpensive, and low maintenance. It serves as the brain of the mineral processing plant and is used to process water in important sectors of the textile, petroleum, chemical, paper, and agricultural industries. It is made up of a cylindrical and a conical portion. Three holes are present—two outputs and one for the feed intake. The under flow was for pollutant outlet and the vortex finder was for water outlet. Pressure drop, geometrical factors, and feed size distribution all have an impact on the hydrocyclone's efficiency. The present work reviews the shape optimization of vortex finder, spigots, air core and walls of the hydrocyclone for enhancing the desired outcome of the hydrocyclone.

Two new species of Xyalidae (Nematoda: Monhysterida) from intertidal zone of the Bohai Sea, China

Two new nematode species are described from the intertidal zone of the Bohai Sea, China. Paramonohystera gracilis sp. nov. is characterized by slender body with a long filiform tail; oval amphidial fovea 6 µm in diameter; spicules slender, 3.4 a.b.d. long; gubernaculum small, plate shaped without apophysis. It differs from the most similar species P. riemanni (Platt, 1973) Lorenzen, 1977 by much slender body and longer filiform tail. Amphimonhystrella boucheri sp. nov. is characterized by short body, deep buccal cavity with funnel shaped anterior portion, circular amphids, conico-cylindrical tail with two thirds conical anterior portion and a third cylindrical posterior portion, small spicules L-shaped and gubernaculum with short apophysis. It is distinguished from the most similar species A. unita Lorenzen, 1977 in buccal cavity funnel shaped, small amphidial fovea circular, spicules short with tapered distal end. Updated keys for valid species of Paramonohystera and Amphimonhystrella are provided.

Analyzing ballistic impact of bullet over laminated test specimen

Impact analysis of an object over a test specimen is a major design related aspect related to toughness of the material. Based on review, different parameters affecting the ballistic impact were analyzed. Parameters having a major effect on impact were found to be apex angle, thickness, and composite material parameters. A projectile impact of bullet on laminated test specimen was carried experimentally and simulated with explicit dynamics approach using Ansys®. The bullet shears certain amount from laminated test specimen on impact and passes out. The ballistic limit of laminated test specimens of varied thickness was analyzed for projectiles with 7.6 AP against oblique and normal impact. Projectile's experienced resistance is seen to be greater with greater conical portion's surface area in contact with target.

Tissue-level versus bone-level single implants in the anterior area rehabilitated with feather-edge crowns on conical implant abutments: An up to 5-year retrospective study

Statement of problemLimited information is available on the differences between tissue-level implants with an ultrathin threaded microsurface conical transmucosal portion and bone-level implants rehabilitated with conical custom abutments. PurposeThe purpose of this retrospective study was to assess the outcomes of crowns designed as per the biologically oriented preparation technique (BOPT) cemented on conical titanium abutments on tissue-level and bone-level implants. Material and methodsPatients consecutively rehabilitated with a delayed loading protocol with anterior implant-supported single crowns with a feather-edge margin, in function for at least 4 years, were recruited and divided into 2 groups based on the implant type they had received: tissue-level implants with a conical transmucosal portion or bone-level implants rehabilitated with a conical abutment by following the platform switching concept. Bone resorption, pink esthetic score (PES), and white esthetic score (WES) were collected and analyzed. The nonparametric Mann-Whitney test was performed to analyze all parameters (α=.05 for all tests). ResultsA total of 43 participants (48 implants) were included in the present study. The mean follow-up period was 4.5 years (range 52-64 months). A statistically significant difference (P=.004) was found in the mean ±standard deviation bone resorption between tissue-level implants (0.38 ±0.46 mm) and bone-level implants (0.83 ±0.58 mm). Higher values for both PES and WES were obtained in the tissue-level implant group. ConclusionsWithin the limitations of the present retrospective study, tissue-level implants with a conical transmucosal portion seem to provide a suitable alternative to bone-level implants in the anterior area.

Paragnomoxyala papillifera sp. nov. (Nematoda: Monhysterida) from the Bohai Sea, China

A new free-living marine nematode species of the family Xyalidae from Laizhou Bay of the Bohai Sea, China is described and illustrated herein. Paragnomoxyala papillifera sp. nov. is characterized by large funnel-shaped buccal cavity, circular amphidial fovea located posterior to buccal cavity, straight spicules with slightly curved distal end, gubernaculum absent, four papilliform precloacal supplements, tail conico-cylindrical with two ventral embossments in males and having longitudinal rows of cervical setae and subventral caudal setae in males. The new species is easily identified from other two recorded species in the genus by having papilliform precloacal supplements and ventral embossments along conical portion of tail of males. A pictorial key for three species of Paragnomoxyala and comparative table of three species with important characteristics are provided.

Numerical simulation of flow field over slender bodies at transonic Mach number and low angle of attacks

The transonic flow field over a launch vehicle is complicated due to presence of a normal shockwave on the heat shield. To predict the aerodynamic loads, the shockwave position needs to be predicted accurately. The present work aims at predicting the flow field over a typical launch vehicle at an angle of attack (AOA), and analyzing the effect of AOA on flow field, shockwave position and aerodynamic and moment coefficients. The launch vehicle considered here is a long slender body with spherical nose followed by the conical, cylindrical and boat-tail portions. Simulations are performed at a Mach number of 0.95with AOA of 0°, 2°, and 4°. Commercial Computational Fluid Dynamics package ANSYS Fluent is used for simulations. Density-based algorithm is used to obtain the steady state solutions with explicit time stepping.κ-ω SST turbulence model is used to close the turbulent stresses terms. The surface pressure distribution in axial direction is analyzed to understand the effect of AOA on the aerodynamic and moment coefficients. It is observed that as AOA increases, the normal shockwave moves towards nose. The drag coefficient and pitching moment coefficients are found to increase with increase of AOA.

Evaluation of Different Heights of Prosthetic Crowns Supported by an Ultra-Short Implant Using Three-Dimensional Finite Element Analysis.

To apply finite element analysis (FEA) to investigate the stress distribution in a 4-mm-high ultrashort implant when supporting crowns of different heights in order to test the possibility of using this implant unitarily in the posterior edentulous mandible. Three models of atrophic mandibles were created (M1, M2, and M3). Each model contained a 4-mm-length implant of a titanium-zirconium alloy, screw-type with internal connection, supporting nonsplinted screwed-in crowns of 10, 12.5, and 15 mm in height. Axial and oblique loads were simulated in the three model crowns. In an oblique load, the stress tended to be concentrated in the lingual region. In the qualitative results of the axial load, peaks of tension occurred in the lower angle between the inner groove and the inner conical portion of the implant. Regarding the differences in crown height, the 15-mm height produced a higher stress peak due to the lever effect of the crown under an oblique load. Within the limits of this study, the results suggest the possibility of using single crowns of proposed heights with unitary ultrashort implants installed in the posterior edentulous mandible, so long as there is no oblique load on the crown.

Biomechanical behavior of extra-narrow implants after fatigue and pull-out tests

Statement of problemNarrow implants have limited indications, and implant fracture may occur when these indications are not followed. PurposeThe purpose of this in vitro study was to investigate the mechanical behavior of a 2.9-mm–diameter implant using a fatigue limit test and to investigate the Morse effect of 2 different Morse taper systems, 2.9-mm–diameter (FAC group) and 3.75-mm–diameter (CM group) implants, using a pull-out test. The null hypothesis was that the tensile strengths of the components for both systems would be similar. Material and methodsThe fatigue properties of 13 specimens under 6 loads were determined. The test was performed at 15 Hz and for 5×106 cycles. In the pull-out test, the specimens were divided into 2 groups (n=8), the FAC group (2.9-mm–diameter) and the CM group (3.75-mm–diameter). Statistical analysis for the pull-out test was performed with the Student t test (α=.05). ResultsThirteen specimens underwent the fatigue test. Only 5 did not fail when subjected to the frequency and number of cycles examined. Three of the specimens did not fail under a load of 130 N. The pull-out test showed a significant difference between the FAC and CM groups (P<.001). ConclusionsAccording to the fatigue test, the extra-narrow implant (Facility; Neodent) was compatible with the low masticatory effort regions, as indicated by the manufacturer. The better performance of the FAC group in the pull-out test may be due to its design, which promotes the pure Morse effect in the implant-abutment interface, and the angulation of its internal conical portion.

Three new free-living marine nematode species of Dorylaimopsis (Nematoda: Araeolaimida: Comesomatidae) from the South China Sea and the Chukchi Sea.

Three new species of the free-living marine nematode genus Dorylaimopsis are described from the South China Sea and the Chukchi Sea. Dorylaimopsis longispicula sp. n. is characterized by cuticle with lateral differentiation consisting of four longitudinal rows of larger dots in pharyngeal and tail regions, two rows of larger dots elsewhere, long curved spicules, and 12-16 tubular precloacal supplements. Dorylaimopsis boucheri sp. n. is characterized by lateral differentiation consisting of 3-4 longitudinal rows of larger dots in males and 4-6 rows in females, beginning about 30 μm posterior to amphids and terminating at the conical portion of the tail, 13-16 tubular precloacal supplements, and distal part of tail cylindrical without terminal setae. Dorylaimopsis jinyuei sp. n. is characterized by cuticle with lateral differentiation in the form of longitudinal rows of larger dots in two separate regions, not along entire body. One region is from posterior edge of amphid to anterior of intestine or anterior border of pharyngeal bulb in some females (4-7 longitudinal rows), the other is the tail region (5-7 longitudinal rows). In this paper, Dorylaimopsis metatypica Chitwood, 1936 is transferred to Hopperia because it is characterized by lateral differentiation consisting of larger, irregularly-distributed coarse dots (as in Hopperia), and Hopperia communis Gagarin Nguyen, 2006 is transferred to Dorylaimopsis based on the presence of longitudinal rows of coarse dots and a cylindrical buccal cavity in most specimens of this species. A dichotomous key to valid species of Dorylaimopsis Ditlevsen, 1918 is provided.

Effect of Misfit at Implant-Level Framework and Supporting Bone on Internal Connection Implants: Mechanical and Finite Element Analysis.

To evaluate the effect of misfit at implant-level fixed partial dentures (ILFPDs) and marginal bone support on the generation of implant cracks. This in vitro study included a mechanical fatigue test and finite element analysis. A mechanical cycling loading test was performed using 16 experimental models, each consisting of two parallel implants subdivided into four groups based on the misfit and the supporting bone condition. The framework, firmly seated at implants, was dynamically loaded vertically with a force of 1,600/160 N and 15 Hz for 1 × 106 cycles. Optical microscope, scanning electron microscope (SEM), and computed tomography three-dimensional (CT-3D) analyses were performed to detect impairments. Finite element models, representing the setups in the mechanical fatigue test, were used to represent the fatigue life. None of the mechanical components presented distortion or fracture at the macroscopic level during the test. In a microscopy evaluation, the fatigue test revealed scratches visible in the inner part of the conical portion of the implants regardless of the groups. SEM and CT-3D analysis revealed one implant from the misfit/no bone loss group with a microfracture in the inner part of the conical interface. The simulated effective stress levels in the coronal body were higher in the misfit groups compared with the no misfit groups. The misfit groups presented effective stress levels, above 375 MPa, that penetrated the entire wall thickness. The no bone loss group presented an effective stress level above 375 MPa along its axial direction. In the no misfit group, the area presenting effective stress levels above 375 MPa in the conical connection was larger for the bone loss group compared with the no bone loss group. This study confirmed that implant fracture is an unlikely adverse event. A clear pattern of effective distribution greater than fatigue limit stresses could be noticed when the misfit was present. The dynamic load simulation demonstrated that the crack is more likely to occur when implants are fully supported by marginal bone compared with a bone loss scenario. Within the limitations of this study, it is speculated that marginal bone loss might follow the appearance of an undetected crack. Further research is needed to develop safe clinical protocols with regard to ILFPD.

Crushing behavior of multi-component conical tubes as energy absorber: A comparative analysis between end-capped and non-capped conical tubes

Design of multi-component absorber is a method to improve the specific energy absorption (SEA) and reduce the peak crushing load at the time of the initial accident. In this study, multi-component conical specimens are made from aluminium in the form of end-capped and non-capped. To do so, a long conical tube is divided into several shorter thin-walled conical portions, so that the thickness, length and mechanical properties of the wall vary along the tube length. The purpose of this new design on the conical absorber is to modify performance of shock absorber including decrease of initial peak crushing load and increase of SEA. Therefore, a series of quasi-static experimental tests are carried out on the end-capped and non-capped multi-component conical tubes and parameters of energy absorption, initial peak load, crush force efficiency and SEA are calculated. The results show that the maximum crushing load in simple conical tubes begins at first folding, while it is shifted to the end of the crushing process in multi-component conical tubes. Also, it is shown that the SEA and the crush force efficiency of the non-capped multi-component specimens were further in comparison with the end-capped ones. Finally, it was found that by using this type of the energy absorber, damage to the main structure and also the occupants of car was decreased.

Two new species of free-living nematodes of genus Tripyloides (Nematoda: Enoplida: Tripyloididae) from mangrove wetlands in the Xiamen Bay, China

Two new species of free living nematodes Tripyloides mangrovensis n. sp. and Tripyloides amoyanus n. sp. of genus Tripyloides de Man, 1886 are described from mangroves of the Tong’an Bay and Haimen Island in the Xiamen Bay, China. The two species are both characterized by six stout outer labial setae, male without preanal papillae, tail conico-cylindrical without swollen terminally. Tripyloides mangrovensis n. sp. can be additionally by its buccal cavity consisting of two parts, amphid circular, distinct proximal conical and distal slender cylindrical portions, 2/3 of the tail cylindrical. Tripyloides amoyanus n. sp. is distinguished by buccal cavity consisting of three parts with small tooth, amphid small, rounded, like a comma-shaped loop, 1/3 of the tail cylindrical, gubernaculum with four denticles.

Deformation Type in Forming of Horn Tubes

The purpose of this research is the development of technology to make complex-shape closed-section parts directly from sheet blanks (direct sheet forming). It is expected to form closed-section parts with large expansion of the circumferential length by direct sheet forming. In this paper, the deformation type of horn tubes, which consists of circular, conical and transient portions, is studied. The horn tube is one of the typical shapes for automotive parts. With reference to deformation types in the conventional stamping process, those in the forming process of horn tubes are discussed on the basis of the results of FEM analysis. The validity of FEM analysis is confirmed by comparison with experimental results. It is clarified that the forming process can be broken down into several stages and deformation types (uniform bending of sheet, stretch flanging, axial bending of U-section, deformation into double curved surface and plane-strain compression).

Influence of the Prosthetic Index on Fracture Resistance of Morse Taper Dental Implants.

Manufacturers have inserted a prosthetic index, an internal hexagon to guide prosthetic components inside Morse taper implants. However, it is still unclear if this mechanism could decrease the mechanical strength of Morse taper implants. The aim of this study was to evaluate the influence of the prosthetic index inside Morse taper implants on fracture resistance compared with nonindexed implants. Fifty-seven Morse taper implants, with 11.5-degree angulation of the internal conical portion, were divided into three groups: implants without the prosthetic index and solid Morse taper universal post (group 1), implants with the prosthetic index and solid Morse taper universal post (group 2), and implants and abutments with the prosthetic index (group 3). All groups were modeled for finite element stress analysis (FEA), simulating force application of a perpendicular load to the abutments. Fracture resistance (n = 10) was determined under the same condition. Dynamic loading (n = 9) was also performed. The statistical analysis was performed using one-way analysis of variance (ANOVA), and the Tukey test was applied (α = .05). The metallographic analysis was used to identify the fracture distribution and the microstructure of the titanium alloy. There was no statistically significant difference between the values of all tested groups. According to the FEA, the prosthetic index region was out of stress. The mean fracture resistances and loading test were 353.7 N and 200 N for group 1, 397.3 N and 170 N for group 2, and 372.0 N and 160 N for group 3, respectively. Metallographic analysis showed a macroscopic failure pattern just as demonstrated by FEA. The presence of the prosthetic index on Morse taper implants did not decrease its resistance to fracture for the tested implants.

Experimental investigation of surface flow pattern on truncated cones in Mach 5 flow: Influence of truncation ratio

The flow characteristics on a truncated cone with a cylinder were experimentally investigated in a Mach 5 flow with a Reynolds number 3.8×105, based on the cylindrical diameter. Two different truncation ratios of 0.5 and 0.7 were used. The incidence angle varied from −12 to 0° with 3° intervals to investigate the influence of the truncation ratio on the surface flow pattern. The measurement techniques: unsteady pressure-sensitive paint (anodized aluminium method), color Schlieren photography, and surface oil flow were used. It was found that the distance of the external shock wave from the conical surface depends on the truncation ratio, and the surface pressure on the conical portion increases when the external shock wave moves closer to the model surface. The “external” shock wave denotes a detached shock wave and the “internal” one is the shock wave formed between the detached bow shock wave and the model surface. In the higher truncation ratio at the higher incidence angle, the internal shock wave induced by the flow separation on the conical surface impinges on the external shock wave, which results in its reflection. This reflection leads to the pressure increase on the model surface. On the other hand, this reflection does not appear in the lower truncation ratio. In spite of the different truncation ratios, the angle of the internal shock wave is identical at the same incidence angle. From the oil flow results, the wall shear stress on the leeward conical surface is lager in the higher truncation ratio model.

Molecular characterisation of five nematode species (Chromadorida,Selachinematidae) from shelf and upper slope sediments off New Zealand, with description of three new species.

Limited molecular sequence data are available for selachinematid nematodes, with little or no data from the Southern Hemisphere or habitats beyond the subtidal zone. Here, we provide molecular sequence data for the small subunit (SSU) 18S rDNA gene and D2-D3 region of large subunit (LSU) 28S rDNA gene of three new (Cheironchus haurakiensis n. sp., Halichoanolaimus anisospermus n. sp., and Bendiella longicauda n. sp.) and two known selachinematid species (Pseudocheironchus ingluviosus Leduc, 2013 and Synonchiella rotundicauda Leduc, 2013) from shelf and upper slope environments off northeastern New Zealand. Cheironchus haurakiensis n. sp. is characterised by having a multispiral amphideal fovea with five turns, lateroventral mandibles with central arm curved distally and bearing 4-5 pointed projections, and each palm bearing 4-5 pointed projections, ten precloacal supplements in a 1 + 9 arrangement, spicules 78 µm long, and blunt conical tail with thickened cuticle. Halichoanolaimus anisospermus n. sp. is characterised by having an amphideal fovea with 5-6 turns, anterior portion of buccal cavity with cuticularised rhabdions terminating in three sets of seven pairs of teeth (denticles), with the central pair of each set positioned above the other six, dimorphism in size of sperm cells between anterior and posterior testes, gubernaculum consisting of two detached lateral pieces (crurae) tapering distally, three small precloacal supplements consisting of slightly thickened and raised cuticle, and a conicocylindrical tail with conical portion 32-38% of total tail length. Bendiella longicauda n. sp. is characterised by having two dorsosublateral rows of pores from midbody to level of cloaca, amphideal fovea with 4.5 turns, posterior rhabdions with numerous small denticles, spicules 2.1 cloacal body diameters long, a conicocylindrical tail 13.3 cloacal body diameters long and with conical portion 8% of tail length. Preliminary phylogenetic analyses for the family Selachinematidae do not provide evidence of clustering according to depth (intertidal/subtidal vs shelf/upper slope) or geographical location (New Zealand vs Northern Hemisphere). The number of available Selachinematidae sequences, however, remains limited and comprehensive analyses based on larger number of sequences will be necessary to provide more solid conclusions.

Ratcheting analysis of joined conical cylindrical shells

The ratcheting and strain cyclic behaviour of joined conical-cylindrical shells under uniaxial strain controlled, uniaxial and multiaxial stress controlled cyclic loading are investigated in the paper. The elasto-plastic deformation of the structure is simulated using Chaboche non-linear kinematic hardening model in finite element package ANSYS 13.0. The stress-strain response near the joint of conical and cylindrical shell portions is discussed in detail. The effects of strain amplitude, mean stress, stress amplitude and temperature on ratcheting are investigated. Under strain symmetric cycling, the stress amplitude increases with the increase in imposed strain amplitude. Under imposed uniaxial/multiaxial stress cycling, ratcheting strain increases with the increasing mean/amplitude values of stress and temperature. The abrupt change in geometry at the joint results in local plastic deformation inducing large strain variations in the vicinity of the joint. The forcing frequency corresponding to peak axial ratcheting strain amplitude is significantly smaller than the frequency of first linear elastic axial vibration mode. The strains predicted from quasi static analysis are significantly smaller as compared to the peak strains from dynamic analysis.