Lump Formation Research Articles

Obstructive Role of the Dimorphic Sperm in a Non-copulatory Marine Sculpin, Hemilepidotus gilberti, to Prevent Other Males' Eusperm from Fertilization

In many species of animals, males normally produce parasperm (dimorphic sperm) along with eusperm (normal sperm) during spermatogenesis. In the present study, to clarify the role of parasperm of the non-copulatory sculpin Hemilepidotus gilberti, whose reproduction is characterized by polyandrous oviposition involving sneaking by neighboring territorial males, we observed the movements of parasperm. Parasperm could not move by themselves, but they were transported in solutions by passive movement due to collisions with actively swimming eusperm. In the viscous ovarian fluid (OF), which isolates eggs from seawater by covering them during spawning, parasperm did not exhibit any movement. However, they could be transported by eusperm movement in solutions with dissolved OF, partly because the viscosity of the fluid become lower. And then, in some solutions parasperm formed lumps. Lump formation of parasperm was also observed at the boundary surface of an egg mass where OF contacted seawater. Eusperm added experimentally to a solution in which parasperm were forming lumps were engulfed in the lumps and never escaped. Thus, lump formation of parasperm would be obstacles for the later arriving eusperm. Although lumps formed against both kin and non-kin eusperm, parasperm are thought to be available to overcome sperm competition which would occur during spawning that involves sneaking being almost concurrent with lump formation. The territorial male eusperm reach the eggs while his parasperm hinder other males' eusperm from reaching the eggs. Thus, we concluded that parasperm of H. gilberti play a role on protection of paternity by blocking rival eusperm physically from approaching eggs.

Two-Dimensional Solitons and their Interactions on a Continuous-Wave Background

Using a cubic-quintic nonlinear Schrödinger equation as a model, we study the existence and interactions of two-dimensional (2D) solitons on top of a continuous-wave background. It is shown that the 2D solitons exist in the form of dark or antidark lumps, which are described by an effective KP (Kadomtsev-Petviashvili)-I equation. Interactions and collisions of 2D solitons are investigated using both analytical and numerical techniques. The most remarkable feature of the interaction is formation of a transient long-lived quasi-bound state of two colliding solitons, before they separate.

Statistics of the detection rates for tensor and scalar gravitational waves from the Local Galaxy universe

We use data on the local 3-dimensional galaxy distribution for studying the statistics of the detection rates of gravitational waves (GW) coming from supernova explosions. We consider both tensor and scalar grav- itational waves which are possible in a wide range of relativistic and quantum gravity theories. We show that statistics of GW events as a function of sidereal time can be used for distinction between scalar and tensor gravi- tational waves because of the anisotropy of spatial galaxy distribution. For calculation of the expected amplitudes of GW signals we use the values of the released GW energy, frequency and duration of GW pulse which are consistent with existing scenarios of SN core collapse. The amplitudes of the signals produced by Virgo and the Great Attractor clusters of galaxies is expressed as a function of the sidereal time for resonant bar detectors oper- ating now (IGEC) and for forthcoming laser interferometric detectors (VIRGO). Then, we calculate the expected number of GW events as a function of sidereal time produced by all the galaxies within 100 Mpc. In the case of axisymmetric rotational core collapse which radiates a GW energy of 10 9 Mc 2 , only the closest explosions can be detected. However, in the case of nonaxisymmetric supernova explosion, due to such phenomena as centrifugal hangup, bar and lump formation, the GW radiation could be as strong as that from a coalescing neutron-star binary. For radiated GW energy higher than 10 6 Mc 2 and sensitivity of detectors at the level h 10 23 it is possible to detect Virgo cluster and Great Attractor, and hence to use the statistics of GW events for testing gravity theories.

Effect Of Capping Layer During Annealing of Low-Dose Lowenergy Simox Materials

Abstract Ultra-thin Silicon-On-Insulator (SOI) materials are becoming increasingly attractive for fabrication of ultra-large scale integrated (ULSI) devices due to their performance, speed, and power reduction advantages [1]. In SIMOX (Separation by IMplanted OXygen) materials, extensive damage can be repaired by high-temperature annealing in an argon ambient. A small percentage of oxygen is added to give a sufficient oxygen partial pressure to prevent formation of silicon monoxide lumps and subsequent pits [2]. Capping the sample surface to prevent external thermal oxidation during annealing is important to preserve the thickness of the top silicon layer. This is particularly critical for the ultra-thin SIMOX produced by the low-dose low-energy process. However, the surface capping also affects the formation of the buried oxide (BOX). To study this effect, two sets of samples implanted at the same doses of 1.5, 2.0, 2.5, and 3.0x 1017O+ /cm2 at 65keV were annealed with or without protective cap on the sample surface.

Dissolution kinetics of polymer powders

AbstractThe dissolution kinetics of polymer powders as isolated grains or in beds were studied theoretically and experimentally. A simple model developed for the dissolution of a dispersion of isolated grains with an arbitrary size distribution was confirmed experimentally using polysaccharides in water. Based on experimental data for the dissolution of lump‐forming powder beds, modeled using a bimodal population of grains and lumps, a robust technique was developed for analyzing experimental data, which is independent of the details of lump formation. A qualitative picture of lump formation is described, based on the idea that during the initial hydration of a powder bed a “pore blocking” condition quickly develops due to the formation of a gel layer around the dry grains. Once formed, lumps dissolved the same way and with the same kinetic description, as individual, dispersed grains.

Structural transformation of CsI thin film photocathodes under exposure to air and UV irradiation

Transmission electron microscopy has been employed to study the structure of polycrystalline CsI thin films and its transformation under exposure to humid air and UV irradiation. The catastrophic degradation of CsI thin film photocathode performance is shown to be associated with the film dissolving followed by its re-crystallization. This results in the formation of large lumps of CsI crystal on the substrate surface, so that the film becomes discontinuous and its performance as a photocathode is permanently degraded. No change in the surface morphology and the film crystalline structure was observed after the samples were UV irradiated.

Turret exostosis of the phalanges presenting as limited motion of the finger

Turret exostosis, or acquired osteochondroma, was first described by Wissinger et al. as a subperiosteal bone formation which develops beneath the extensor apparatus It shares common clinical and radiological features with florid reactive periostitis and bizarre periosteal osteochondromatous proliferation (Nora’s lesion) which belong to the same group of reactive lesions of the bone surface. Turret exostosis is a rare complication of a minor injury to the hand. Its peak incidence is in the third and fourth decades of life, predominantly affecting the proximal and middle phalanges of the hand. Metacarpal involvement has also been reported. It is characterized by pain, soft tissue swelling and a growing mass leading to limitation of motion and cosmetic deformity. This is a report of seven patients in whom lump formation and limitation of motion were the presenting symptoms of turret exostosis. The literature is reviewed and the possible pathogenesis of this disorder is discussed.

Neutron density fluctuations due to randomly distributed sources in finite media

We formulate a theory which describes the effect on the neutron flux of sources in the form of lumps randomly distributed in a finite medium. One-speed diffusion theory is used, but the method can readily be extended to energy-dependent transport theory. The mean flux, the covariance and a new statistical indicator, the mean flux difference between regions, are calculated for an infinite and semi-infinite medium. Numerical results are obtained using Markov and Gaussian models for the random geometry of the lumps. We conclude that the statistical anisotropy of the medium can play a significant role and that, even though we may be considering what is ostensibly a one-dimensional problem in the x-direction, it is necessary to incorporate the medium properties in the other two directions via the correlation lengths λ y and λ z . We also note that there can be marked differences in the average fluxes in the various source regions which can deviate considerably from the conventional average flux. These results may have practical implications in the design of radioactive waste drums in which sources of neutrons (or gamma rays) are encased randomly in a background matrix. Conventional averaging may lead to a significant underestimate of the surface flux and current. The theory neglects the associated random material properties but should be a good approximation if the volume fraction of the source material is small. In the Appendix, we develop a random geometry model for the source lumps and derive the associated covariance function.

Study of Heat Pump System using Stored Ground Water. The Effect of Iron Rust upon Heat Transfer and Iron Lump Removal Method within Heat Exchanger.

This paper describes an experimental and observational study of iron rust removal method and iron lump formation mechanism within a heat exchanger of a small type heat pump. Since a heat exchanger of a heat pump using water is corroded, heat transfer coefficient (in other words, C.O.P.) is decreased. In this study, iron rust removal system was proposed and cleared the effectiveness. Moreover, iron lump formation mechanism was clarified by an experiment with a double pipe heat exchanger. The conclusions were as follows. 1.C.O.P. of a small type heat pump was recovered by the iron rust removal system. 2.C.O.P. decrease of a heat pump is caused by iron lump grown within a heat exchanger. The source of this iron lump is not the iron rust including water, but the iron rust produced from a heat exchanger.

A novel method for determining the dissolution kinetics of hydrocolloid powders

Food hydrocolloids are sold as powders so they must be dissolved before use. In modern manufacturing practice, rapid dissolution can be an important specification. However, quantifying dissolution kinetics is a problem, because when lumps form the process becomes irreproducible, partly because lumps tend to stick to the stirrer. This paper presents a simple method for determining the dissolution kinetics of soluble polymer powders which solves these problems. The dissolution kinetics were followed using a modified rotational viscometer. The key modification is that when the powder is added, there is a vortex below the axis of the rotor, so that the powder cannot stick to it. The amount of hydrocolloid dissolved is followed via the torque on the viscometer. Measurements were performed under both dispersing and non-dispersing conditions. Under dispersing conditions each powder grain dissolves individually, and it is shown that the dissolution rate is proportional to the amount of powder surface. Under non-dispersing conditions, grains can stick together, forming lumps. The reproducibility of the method under both conditions is demonstrated using pectin. It was used to quantify the empirical observation that reducing the powder grain size increases the dissolution rate, but it also greatly increases lump formation.

Reducing dust and improving granule and tablet quality in the roller compaction process

The dramatic reduction of non-compacted material during roller compaction and an important improvement of the granule and tablet qualities were obtained by a controlled wetting process before the roller compaction. The continuity of the roller compaction process was maintained by using a continuous fluid bed system. Due to a controlled water addition, a better binder distribution was obtained than when using micronised dry binders. When dry compacting poorly water soluble hydrochlorothiazide mixtures, the resultant dissolution rate was not influenced by the HPMC binder viscosity. When moistened blends were compacted, the resultant dissolution rate decreased with increasing HPMC binder viscosity. The roller compaction pressure had almost no influence on the drug dissolution rate. The addition of disintegrants did not improve the dissolution rate. When a fraction of the filler α-lactose monohydrate was replaced by microcrystalline cellulose, the dissolution rate increased with an increasing microcrystalline cellulose fraction. With the addition of 0.5% Tween® 80 to a formulation containing 25% microcrystalline cellulose and 50% α-lactose monohydrate, the dissolution rate increased and an immediate release tablet formulation was obtained. The presence of microcrystalline cellulose also improved the processing and avoided lump formation.

Mathematical model of sugar dehydration during storage in a laboratory silo

In the industrial processing of sugar beet, after drying and cooling, the sugar crystals are still likely to contain water. During storage in silos, the bound water on the crystal surface is changed into free water that enhances caking and the formation of lumps. Preventing caking requires a good knowledge of mass and heat transfer phenomena. To obtain this information, a laboratory silo was built and equipped out with thermohygrometers. Moreover, a model based on transient mass and heat balances was conceived which correlated well with experimental results (i.e. the temperature and humidity of air and the moisture content of sugar). Identification of certain parameters such as the mass transfer coefficient for sugar dehydration was thus possible.

97/03660 Oil sand hydrotransport tests at Syncrude Canada Ltd

In the Athabasca region of Northern Alberta there are major deposits of oil sands. Two large scale commercial plants are involved in mining oil sands and production of synthetic crude oil. Suncor (previously Great Canadian Oil Sands or GCOS) has been in operation since 1968 and currently produces over 25 M barrels of oil per year. Syncrude Canada Ltd. plant started operation in 1978 and currently produces over 65 M barrels (10.4 {times} 10{sup 3} m{sup 3}) of light sweet synthetic crude oil per year. Together the two operations provide 16 % of Canada`s oil output The plant located 50 km north of Fort McMurray, Alberta, is a joint venture of 9 participants. The oil sand typically contains 9 to 12 % bitumen, up to 30 % clay and 5 % water. The remainder is silica sand, finer than 150 {mu}m. Properties of oil sand are described in detail by Nonth, Ruhl and Tissot. The bulk of the plant feed is in the form of lumps ranging in size from several mm to 10 cm. It also includes lenses of soft clays and large rocks. The material is difficult to handle; sticky in summer and hard in winter. It requiresmore » special materials and design considerations for belt conveyors, transfer points, feeders etc..« less

Optically transparent and non-linear LiNbO3 : polyimide composite : preparation and characterization

Ferroelectric materials, both in single crystal and ceramic form, are being used and studied for their applications in various devices. Ferroelectric ceramic thin films have received increasing interest during recent years due to the possibility of their use in thin film capacitors [1], piezoelectric transducers [2], SAW devices [3], IR detectors [4], electro-optic wave guides and other optically non linear devices [5, 6]. Various preparation techniques such as evaporation [7], sputtering [8], CVD, sol-gel [9, 10] etc., have been developed to deposit thin films. The main advantage of the sol-gel technique is that it gives optical quality films without expensive infrastructure, at a fairly low processing temperature. In the sol-gel technique, films are prepared using metal alkoxide precursors by either spin coating the sol on a substrate or dip coating the substrate. The films are sintered at 500 to 600 8C. The film thickness can be increased by increasing the number of coatings. However, it has been observed that as the film thickness increases beyond a few micrometres, film adhesion becomes poor and cracks also start to develop. Moreover, the substrate on which the film is being deposited also plays an important role in its characteristics. For non-linear optical devices, thicker films are required to increase the optical interaction length, and, as such, sol-gel derived films are not very suitable, especially for transversal exposure. To increase the thickness of the films without compromising the mechanical properties, we have prepared ceramic:polymer composite films. The polymer used for this purpose is polyimide, which can withstand the desired sintering temperatures [11]. This paper deals with the preparation of LiNbO3:Polyimide composite films. Structural, optical and electrical characterization of these films is also reported. Polyimide (PI) films were prepared by dissolving equimolecular proportions of 4-4 diamino diphenyl methane and tetracarboxylic acid in DMF to obtained polyamic acid. The viscosity of polyamic acid was adjusted to give films of about 40–50 im thickness. Films of polyamic acid were cast on glass substrates and were dried in a vacuum oven at 60 8C. Imidisation was done by sintering these films at 350 8C for two hours. To prepare polyimide:LiNbO3 composite films, ammonium salt of polyamic acid was prepared by adding ammonium hydroxide to polyamic acid. This ammonium salt of polyamic acid was dissolved in alcohol and was used for composite film preparation. A sol of LiNbO3 was prepared by dissolving lithium hydroxide in absolute ethanol and adding an equimolecular amount of niobium ethoxide to it. This sol was added dropwise to the prepared alcoholic solution of polyamic acid with continuous stirring to avoid gelation or lump formation. Composite films were then cast from this solution. Drying of the composite film and imidisation were carried out as mentioned earlier for the polyimide films. The thickness of the films thus obtained was about 35 im. A weighed portion of the film was burnt at 700 8C in a crucible. The residue, which was LiNbO3, was weighed and the weight percentage of LiNbO3 in the composite was determined to be about 15%. The X-ray diffractogram of the film was taken on a Rigaku diffractometer, while the optical transmission was recorded on a Hitachi spectrophotometer. A scanning electron micrograph was taken on a Philips scanning electron microscope. Aluminium electrodes of 1 cm diameter were vacuum deposited on the film for electrical measurements. Dielectric measurements were carried out on a Hewlett Packard impedance analyzer. Optical phase conjugation was carried out using a 35 mW He-Ne laser. The X-ray diffractogram of the film is shown in Fig. 1. The presence of LiNbO3 crystallites in the composite is clearly indicated by the presence of broad and clear peaks. The planes responsible for these peaks are marked on the diffractogram. The broadness of the peaks suggests that the crystallisation of LiNbO3 has just begun.

Construction of the Vilyui hydroelectric station No. 3

The Vilyui hydroelectric station No. 3 (HES-3) is being constructed as the second step of the cascade of Vilyui hydroelectric stations 141 km below the operating Vilyui HES-1 and -2 (the first step of the cascade) and 1250 km from the mouth of the Vilyui River. The closest large populated areas are: Mirnyi. the economic and administrative center of the Western Yakutia region located 80 km south of the site of the hydrostation under construction; Chernyshevskii, the village of operators of the Vilyui HES-1 and -2 and the main production facility of the cascade, located 100 km from the site along the highway: the villages Aikhal and Udachnyi, diamond-mining centers, located 450-500 km to the north, beyond the Arctic Circle. A village of the Svetlyi type was created near the construction site. The closest port and main transshipment facility is Lensk City located on the Lena River 950 krn below the port of Osetrovo (Ust'-Kut railroad station on the Baikal-Amur Mainline) and is connected with the construction site by a permanently operating highway 300 krn long. Yakutsk, the capital of the Republic of Sakha, is located 900 km east of the construction region. The main power consumers in the region are enterprises of the diamond-mining industry, composing the basis of the regional economic complex, as well as the construction industry and welfare sector. The plans of economic development of western regions of Yakutia envisage a more than doubling of power consumption by 2000. Power production of the Vilyui HES-1 and -2 has presently reached the design indices, and a further increase of the loads will lead to a shortage in the region, the only source for covering which is the Vilyui HES-3. The hydrostation with an installed capacity of 360 MW and average annual production of 1.2 billion kWh is intended to operate in the Western Yakutia power system and later in the interconnected power system of Western and Central Yakutia. The Vilyui HES-3 is being constructed in a region with a harsh, markedly continental climate, located only 2.5 ~ south of the Arctic Circle, in the permafrost zone, and belongs to regions of the Far North. The mean annual air temperature is 9.7~ the mean January temperature is minus 35~ the observed extreme values of the January and July temperatures are respectively minus 63 and plus 36~ The average duration of the snow cover is 220 days, freezeup 190-220 days, and heating period 270 days. The average annual amount of precipitation is 330 ram. The drainage area of the Vilyui at the site of the hydro development is 156,000 km 2, the average annual discharge is 681 m3/sec. The natural hydrologic regime of the river has been altered to a considerable extent due to carryover regulation by the reservoir of the Vilyui HES-1 and -2. The Vilyui River at the site flows in a narrow canyon-like valley with slopes with a steepness up to 30-45 o without expressed terraces. The channel width at the waterline at the site of the hydrostation is about 150 m, the valley width at the elevation of the normal pool level (NPL) is 350-500 m. The divides and upper parts of the valley slopes are composed of dolerites, in the lower part of the slopes and channel part of the valley occurs a carbonate-argillaceous intercalating stratum of marls, limestones, dolomites, and sandstones severely fractured and here and there weathered to loams. The river slopes and bottom are covered by a stratum of Quaternary deposits. The permafrost with a thickness up to 300-320 m and temperature to minus 9-11~ is interrupted by talik under the river channel. The ice content of the perennially frozen bedrocks is 5-10 %, of the floodplain and slope deposits 5-25 %, and in individual stretches reaches 40-60%. The pores and fractures of the lower level of permafrost are filled with saline waters with a negative temperature (cryopags). Landslide formations in the form of blocks, lumps, rubble, and grus are developed on the left-bank valley slopes.

Galling mechanisms in sheet forming operations

The paper reviews some important observations concerning the initiation of galling for various combinations of tool and sheet materials. The experimental conditions have been chosen to resemble the contact conditions in sheet metal forming. Typically, a hard and smooth tool surface is repeatedly in contact with a soft and rough sheet surface. The plastic wave is introduced as a general mechanism for subsurface plastic working of the contact asperities on the sheet during friction contact. The same mechanism is used to describe the transfer of sheet material to the tool surface. Generally, different types of tool surface defects act as traps for sheet fragments which stick to the tool surface. Typical defects are grinding scratches and holes of various origin. A possible initiation from transfer aluminium oxide to the tool surface for hot-dip galvanized sheet steels has also been observed. The action of defects as initiation sites for sheet material transfer seems to be virtually independent of the material combination, as well as the presence of lubricants. However, the further build up of the transfer layer and formation of big lumps of sheet material on the tool surface is very sensitive to the material combination and the presence of lubricants. Special initiation mechanisms (e.g. aluminium oxide) can, however, be observed in action together with the defect mechanisms.

Effect of dose and modification of viscous properties of oat gum on plasma glucose and insulin following an oral glucose load.

An extract from oats known as oat gum (OG) is composed mainly of the polysaccharide (1-->3) (1-->4)-beta-D-glucan, which is highly viscous in aqueous solution. Viscous polysaccharides are known to attenuate postprandial plasma glucose and insulin responses. The purposes of this study were to determine the dose-response to OG and establish quantitatively the effect of viscosity on plasma glucose and insulin levels of healthy humans consuming 50 g glucose. Increasing the dose of OG successively reduced the plasma glucose and insulin responses relative to a control without gum. Reduction of the viscosity of OG by acid hydrolysis reduced or eliminated the capacity to decrease postprandial glucose and insulin levels. The ability of OG to modify glycaemic response was unchanged following agglomeration in the presence of maltodextrin. Agglomerated gum dispersed smoothly in a drink without formation of lumps, and development of maximum viscosity was delayed. These properties improve palatability. There was a highly significant linear relationship between log[viscosity] of the mixtures consumed and the glucose and insulin responses. The relationship shows that 79-96% of the changes in plasma glucose and insulin are attributable to viscosity, and that changes occur at relatively low doses and viscosities.

Effect of Liquid Viscosity on Liquid Lump Velocity in Vertical Upward Gas-Liquid Two-Phase Flow.1st Report, Mean Liquid Lump Velocity and Its Standard Deviation.

Experimental data are presented on the liquid lump velocities in vertical upward gas-liquid two-phase flow. The liquids used in this experiment are water and glycerol solutions, and the kinematic viscosity of these liquids ranges from 1.0×10-6 to 15.5×10-6 m2/s. Flow regimes concerned herein cover plug flow, huge wave flow and annular flow. Velocities of liquid lumps, such as liquid slugs, huge waves, disturbance waves or ephemeral large waves, are determined using two sets of signals of time-varying cross-sectional mean liquid holdups which are electrically detected at two axially separated locations in the test tube. It is first described, from the observations of liquid holdup signals, that the liquid viscosity affects the formation of liquid lumps or the appearance frequency of the same kind of liquid lump under the same gas and liquid flow rates. Next, the mean values of liquid lump velocity and their standard deviations are discussed with attention paid to the effect of liquid viscosity.

Extraperiosteal paraffine plombage thoracoplasty for pulmonary tuberculosis.

Background: From 1973 we performed EPPT for the 3,500 cases of the cavitary tuberculosis who were not responded well to the antimicrobial drugs, and we evaluated the 1,003 cases who could be followed up to more than 3 years postoperatively. Method: The key of the EPPT was that the 5-8 ribs of unilateral chest were denuded at the one stage operation and the paraffine was used as the plomb of filling the dead space out of the collapsed periosteums and intercostal muscles. Result and Conclusion: Number of patients who had unilateral EPPT was 759 and bilateral 244. The late complication were subscapular abscess (12) lump formation (42) and paraffine expectoration (26). All of those complications was cured after removal of the packed paraffine. Sputum conversion rates were 91.6% in the group with cavity less than 3 cm and 41.8% in the group with cavity bigger than 5cm.

固形化湿雪の空気力管路輸送に関する研究

固形化湿雪の空気力管路輸送に関する研究