Number Of Striations Research Articles

Measurements of Coupling Time Constants and Geometry Factors of Coupling Losses in Spiral Copper-Plated Multifilament Coated Conductors

Spiral geometry is effective to reduce coupling time constants of copper-plated multifilament coated conductors. We wound copper-plated multifilament coated conductors with various specifications spirally on round cores, and measured their magnetization losses in a wide range of frequency to determine their coupling time constants as well as the geometry factors of coupling losses. The core diameter was decreased down to 2.5 mm in order to show the feasibility of such conductors with reasonably high overall current density. The influence of various conductor parameters such as copper thickness, conductor width, and number of striations (filament width) as well as core diameter on coupling time constants and geometry factors were studied. By using the obtained coupling time constants and geometry factors, we calculated coupling losses of various conductors, whereas we calculated their hysteresis losses by using Brandt and Indenbom's formulae. These calculated hysteresis losses and coupling losses were compared with measured magnetization losses for various conductors.

Impact of Copper Thickness, Conductor Width, and Number of Striations on Coupling Loss Characteristics of Copper-Plated Multifilament-Coated Conductors

This article investigates the coupling loss characteristics of multifilament-coated conductors that have been plated with copper to connect electrically all the filaments to enhance their stability. Short pieces of copper-plated multifilament-coated conductors were prepared, each of which simulated a half-pitch of the conductor wound spirally on a round core with respect to the loop of the coupling current, and their magnetization losses were measured. The measured magnetization loss was separated into the hysteresis and coupling losses. This article focused on the latter one, which is peculiar to copper-plated multifilament-coated conductors, and the reduction of which is important for their applications. The coupling time constants as well as the geometry factors of the coupling losses and the magnitudes of coupling losses were studied using copper-plated multifilament-coated conductors with various copper thicknesses, numbers of striations, and conductor widths. Numerical electromagnetic field analyses were conducted, and the numerical and measured results were compared.

Characteristics of tiger moth (Erebidae: Arctiinae) anti-bat sounds can be predicted from tymbal morphology

BackgroundAcoustic signals are used by many animals to transmit information. Variation in the acoustic characteristics of these signals often covaries with morphology and can relay information about an individual’s fitness, sex, species, and/or other characteristics important for both mating and defense. Tiger moths (Lepidoptera: Erebidae: Arctiinae) use modified cuticular plates called “tymbal organs” to produce ultrasonic clicks which can aposematically signal their toxicity, mimic the signals of other species, or, in some cases, disrupt bat echolocation. The morphology of the tymbal organs and the sounds they produce vary greatly between species, but it is unclear how the variation in morphology gives rise to the variation in acoustic characteristics. This is the first study to determine how the morphological features of tymbals can predict the acoustic characteristics of the signals they produce.ResultsWe show that the number of striations on the tymbal surface (historically known as “microtymbals”) and, to a lesser extent, the ratio of the projected surface area of the tymbal to that of the thorax have a strong, positive correlation with the number of clicks a moth produces per unit time. We also found that some clades have significantly different regression coefficients, and thus the relationship between microtymbals and click rate is also dependent on the shared ancestry of different species.ConclusionsOur predictive model allows the click rates of moths to be estimated using preserved material (e.g., from museums) in cases where live specimens are unavailable. This has the potential to greatly accelerate our understanding of the distribution of sound production and acoustic anti-bat strategies employed by tiger moths. Such knowledge will generate new insights into the evolutionary history of tiger moth anti-predator defenses on a global scale.

Achieving superior strength and high ductility in AISI 304 austenitic stainless steel via asymmetric cold rolling

In this study, the microstructure-texture-mechanical properties relationships in AISI 304 austenitic stainless steel processed by asymmetric cold rolling investigated. With increasing the deformation, the number of twins and deformation-induced martensites including α′ and ε increased. Interestingly, after 30% rolling, the volume fraction of martensite decreased from 47.34% to 32.69% due to the occurrence of recrystallization. Texture results indicated that after 30% and 40% deformation, the recrystallization texture increased. Two texture transitions from Goss to Brass at 30% deformation and from Copper to Brass at 40% strain observed. The Copper to Brass transition occurred in three distinct paths. The 40% rolled sample exhibited a quite high hardness of 448.3 HV due to the increasing strain hardening, mechanical twins, martensite phases, and grain refinement. The deformed samples exhibited strong anisotropy of hardness and the hardness on the RD–TD plane is higher than two other planes. The results showed a significant increase in yield (1203.2 MPa) and ultimate tensile (1229.2 MPa) strength in the 40% deformed samples with respect to the initial austenitic steel, while a considerable ductility (23.3%) remained. With increasing the rolling reduction from 10% to 40%, the diameter and depth of the dimples reduced and uniformity of dimples decreased. However, the fracture mode was ductile with sufficient plastic deformation before failure. Finally, with increasing the deformation, the number of striations and fine dimples increased due to the formation of more mechanical twins and fine grains, respectively.

Molecular and morphological characterisation of Pharyngostrongylus kappa Mawson, 1965 (Nematoda: Strongylida) from Australian macropodid marsupials with the description of a new species, P. patriciae n. sp.

BackgroundPharyngostrongylus kappa Mawson, 1965 is a nematode (Strongyloidea: Cloacininae), endemic to the sacculated forestomachs of Australian macropodid marsupials (kangaroos and wallaroos). A recent study revealed genetic variation within the internal transcribed spacer region of the nuclear ribosomal DNA among P. kappa specimens collected from Macropus giganteus Shaw and Osphranter robustus (Gould). This study aimed to characterise the genetic and morphological diversity within P. kappa from four macropodid host species, including M. giganteus, O. robustus, O. antilopinus (Gould) and O. bernardus (Rothschild).MethodsSpecimens of P. kappa from M. giganteus and Osphranter spp. from various localities across Australia were examined. The first and second internal transcribed spacers (ITS1 and ITS2, respectively) were amplified using polymerase chain reaction and sequenced. Phylogenetic methods were used to determine the interspecific diversification within P. kappa and its evolutionary relationship with other congeners.ResultsMorphological examination revealed that P. kappa from M. giganteus, the type-host, can be distinguished from those in Osphranter spp. by the greater length and number of striations on the buccal capsules. DNA sequences showed that P. kappa from M. giganteus was genetically distinct from that in Osphranter spp., thereby supporting the morphological findings. Based on these finding, a new species from Osphranter spp., Pharyngostrongylus patriciae n. sp., is described.ConclusionPharyngostrongylus patriciae n. sp. from Osphranter spp. is distinguished from P. kappa based on molecular and morphological evidence. The study highlights the importance of combining molecular and morphological techniques for advancing the nematode taxonomy. Although ITS genetic markers have proven to be effective for molecular prospecting as claimed in previous studies, future utilisation of mitochondrial DNA to validate ITS data could further elucidate the extent of speciation among macropodid nematodes.

Z-line formins promote contractile lattice growth and maintenance in striated muscles of C. elegans

Muscle contraction depends on interactions between actin and myosin filaments organized into sarcomeres, but the mechanism by which actin filaments incorporate into sarcomeres remains unclear. We have found that, during larval development in Caenorhabditis elegans, two members of the actin-assembling formin family, CYK-1 and FHOD-1, are present in striated body wall muscles near or on sarcomere Z lines, where barbed ends of actin filaments are anchored. Depletion of either formin during this period stunted growth of the striated contractile lattice, whereas their simultaneous reduction profoundly diminished lattice size and number of striations per muscle cell. CYK-1 persisted at Z lines in adulthood, and its near complete depletion from adults triggered phenotypes ranging from partial loss of Z line-associated filamentous actin to collapse of the contractile lattice. These results are, to our knowledge, the first genetic evidence implicating sarcomere-associated formins in the in vivo organization of the muscle cytoskeleton.

In-service fatigue fracture mechanisms in covered disks of a TV3-117VK helicopter turbine engine

In-service propagating fatigue cracks were examined in EI-698VD superalloy thin turbine covered disks of the first, second, and third stages of a TV3-117VK helicopter engine within service lifes of 200–1800 h. To reveal causes of early crack initiation and estimate a propagation time, metallographic and fractographic analyses were performed. The sequence of events during fatigue cracking of the disks was established. A block of striations on the fracture surface was discovered, which characterized fatigue crack propagation during one flight of a helicopter under different operating conditions. The number of striations in each block varied over the range of 4–20, being much more than those used to design covered disks. Fractographic results were used to estimate fatigue crack growth in covered disks of different stages using data on different operating conditions of helicopters.

Redescription of Pseudovorticella cylindrica (Dons, 1915) nov. comb. and Zoothamnium hiketes Precht, 1935, two poorly defined marine peritrichs (Ciliophora: Peritrichia) from the north China Sea

The living morphology, silverline system and infraciliature of two marine peritrichous ciliates, Pseudovorticella cylindrica (Dons, 1915) nov. comb. (formerly Vorticella cylindrica) and Zoothamnium hiketes Precht, 1935, collected in Qingdao, China, were investigated. Based on the Qingdao populations, both species are redefined. Pseudovorticella cylindrica is characterized by: cell inverted bell‐shaped, about 45×50 µm in vivo; macronucleus J‐shaped; one apically positioned contractile vacuole; pellicle smooth with inconspicuous, closely spaced striations; the number of transverse silverlines from peristome to aboral ciliary wreath 33–40, from aboral ciliary wreath to scopula 14–19; the inner row of peniculus 3 conspicuously short. An updated and supplementary description of Zoothamnium hiketes is also supplied: size of zooid in vivo 70×35 µm on average, elongate in shape with inconspicuously double‐layered peristomial lip; macronucleus C‐formed; one large contractile vacuole apically located; colony dichotomously branched; the number of striations from peristome to aboral ciliary wreath 89–109, from aboral ciliary wreath to scopula 35–43; rows in peniculus 3 parallel to each other.

ESTIMATION BY THE GROWTH STRIATIONS FOR GROWTH SPEED OF CORBICULA JAPONICA FROM LAKE OGAWARA

A new technique is developed for estimating the age of a Corbicula Japonica which is one of common aquatic products in brackish water regions in Japan. The basic idea is as follows: Because the number ofstriations between two annual rings are almost constant, the age can be approximately estimated by counting the number of striations on the shell instead of annual rings when annual rings are not clear. A laser telemeter is used for measuring the shape of shells with an accuracy of 1 μ m. All of the measurement processes are automated. As a result, the age and the growth rate of Corbicula Japonica can be easily estimated with a short time.

Hydride morphology and striation formation during delayed hydride cracking in Zr-2.5% Nb

These experiments were designed to study hydride formation at the crack tip, acoustic emission (AE), potential drop (PD) and striation formation during DHC (delayed hydride cracking) in Zr-2.5% Nb. The test material was taken from an especially extrude pressure tube, which showed similar strength properties to normal pressure tube material but somewhat coarser microstructure. In testing at K I below 12 MPa √m at both 200 and 250°C very large striations (> 40 μ at 200 and >50 μm at 250°C) were produced. In simultaneous monitoring with acoustic emission and potential drop, both AE and PD jumps were shown to be monolithic. The number of striations on the fracture surface corresponded to the number of monolithic AE/PD jumps. Tapered shaped hydrides with the thick end adjacent to the crack tip were observed. These hydrides grew in size during the incubation period until they reached the striation length and then fractured monolithically. However, when K I was increased beyond about 12 MPa √m for these same specimens, the striation spacing decreased below 30 μ, the monolithic jumping dissolved into more continuous changes in signals, although the smaller striations were still visible on the fracture surface.

A Theoretical Model of Striated Film-Rupture Applied to the Cylinder-Plane

The author has previously presented a theoretical model of striated film-rupture consisting of a time-dependent linear perturbation analysis applied to the Reynolds equation. After review this model is applied to the cylinder-plane geometry for comparison with theoretical and experimental data due to Savage. Successful prediction of the number of striations for varying (ηU/T) and (R/h0) is achieved.

A Theoretical Model of Striated Film-Rupture

In general, when a thin film of viscous fluid ruptures in the diverging region of flow between a spreader (or roller) and a flat plate, the cavity formed is not uniform, but appears as adjacent air fingers separated by streamers of fluid. A time-dependent linear perturbation analysis is used to examine the nature of such striated film-rupture and, specifically, to predict the number of striations per unit width for varying minimum gap width and the parameter (ηU/T). Good agreement between theory and experiment is obtained.

STUDIES ON MALAYAN FILARIASIS IN CHE-JU IS., KOREA

Scanning electron microscopic observations have been made on the microfilariae of Brugia malayi and B. pahangi which already cast off their sheaths in vitro. The microfilariae of both species have striated appearances. B. malayi microfilaria varies in number of striations between 402 and 442 with an average of 423, and B. pahangi microfilaria between 443 and 485 with an average of 458. Except for the difference in number of striations, B. malayi presents close morphological resemblances to B. pahangi. The anterior end of the microfilaria forms the bluntly rounded cap provided with a wedgeshaped hook and two small pores. The hook measures 0.7-1.1 microns in length and projects backward. Of the two pores, one, rectangular in shape, exists at the center of the cephalic cap and the other, round in shape, lies between the base of the hook and the rectangular pore. Three fang-like spines are situated on the first annulus opposite to the hook side. The spines are equal in length, 0.6-0.7 micron, to one another. The spines usually point backwards, though they are occasionally directed forwards by the withdrawal of the cephalic cap into the cephalic space. The excretory pore lies on around the 150th annulus from the anterior end, but the opening of the anal pore has not been found in the present study. The tail tapers gradually showing striations, though near the end a few annuluses become expanded. The terminal appendage, connected to the last expanded annulus, is 6-7 microns long, club-shaped and striated.

Three new species ofMyxidium(Protozoa:Myxosporidia) parasitic inAnguilla australisRichardson, 1848 andA. dieffenbachiiGray, 1842 in New Zealand

Abstract Three new species of Myxidium are described from New Zealand freshwater eels. M. zealandicum n.sp. is enzootic on the gills of Anguilla australis Richardson, 1848 and A. dieffenbachii Gray, 1842. It resembles M. giardi Cepede, 1906, but differs in the number of spore striations; in this respect it is similar to M. matsuii, Fujita, 1929, but the spores are smaller. The gall, swim, and urinary bladders occasionally contained spores morphologically indistinguishable from those of M. zealandicum. M. serum n.sp is described from mature cysts in the alimentary musculature, and immature cysts in the mesenteric connective tissue, of A. dieffenbachii. M. serum resembles M. matsuii and M. giardi in spore length, and M. giardi in the number of spore striations, but it is more slender in width than either species, and also differs from M. matsuii in polar capsule dimensions and number of striations. Spores of M. acinum n.sp. occur in small ovoid or elongated cysts in the gills of A. australis and A. dieffenb...

STUDIES ON MALAYAN FILARIASIS IN CHE-JU IS., KOREA

Scanning electron microscopic observations have been made on the microfilariae of Brugia malayi and B. pahangi which already cast off their sheaths in vitro. The microfilariae of both species have striated appearances. B. malayi microfilaria varies in number of striations between 402 and 442 with an average of 423, and B. pahangi microfilaria between 443 and 485 with an average of 458. Except for the difference in number of striations, B. malayi presents close morphological resemblances to B. pahangi. The anterior end of the microfilaria forms the bluntly rounded cap provided with a wedgeshaped hook and two small pores. The hook measures 0.7-1.1 microns in length and projects backward. Of the two pores, one, rectangular in shape, exists at the center of the cephalic cap and the other, round in shape, lies between the base of the hook and the rectangular pore. Three fang-like spines are situated on the first annulus opposite to the hook side. The spines are equal in length, 0.6-0.7 micron, to one another. The spines usually point backwards, though they are occasionally directed forwards by the withdrawal of the cephalic cap into the cephalic space. The excretory pore lies on around the 150th annulus from the anterior end, but the opening of the anal pore has not been found in the present study. The tail tapers gradually showing striations, though near the end a few annuluses become expanded. The terminal appendage, connected to the last expanded annulus, is 6-7 microns long, club-shaped and striated.

Fatigue Crack Propagation in Polycarbonate

Various studies have so far been made of fatigue crack propagation about all kinds of engineering materials, but as its essential mechanism has not yet been known an experiment was performed on plane bending fatigue test using a Polycarbonate plate for specimen, and the same is reported hereunder in this paper.The relation that the differentials of the crack length due to the number of repetitions is proportional to the crack length holds with polycarbonate as it does with metals. The number of striations is equal to the number of cycles under high stress, but it is not equal to the number of cycles under low stress. The main crack is propagated by the repeated stress under high stress, but the crack is propagated after the propagating of shear yielding band for several number of cycles under low stress. The relation between the macroscopic propagating rate and the stress intensity factor range follows the formula presented by Paris for metals, and it is certified that the fatigue fracture mechanisms differ essentially under the high and low stresses.

Temperature Fluctuations and Striations in Flux Crystal Growth

Abstract : It is shown that striations in at least one flux-grown crystal (In2O3) are caused by temperature fluctuations of about 0.14 C during crystal growth. These fluctuations originate in the control action of the furnace. Insulation of the crucible reduces the intensity of the fluctuations in the crucible and the number of striations in the crystal. (Author)

THE FORMATION OF STRIATION-TYPE SUBSTRUCTURE IN ALUMINUM

Striations are one type of substructure which can form in metals as they solidify from the melt. The formation of striations is dependent upon the rate of crystal growth, the purity, and the crystallographic orientation. In aluminum single crystals, it was found that striation boundaries tended to approach a preferred (100) growth direction with increasing rate of growth and with increasing solute concentration. With different types of solute, it appears that similar values of the average concentration of solute in the liquid at the solid–liquid interface (C0/k) produced the same effect on striation direction.The number of striations found in any sample appeared to be a complex function of the purity, the orientation, and the rate of growth.