Mode Of Disintegration Research Articles

Методика укладання опису морфо-анатомічної будови плоду за даними світлової мікроскопії

Light microscopy, along with the newest methods of studying the morpho-anatomic structure of the fruit, remains relevant in current carpology as a simple and universal tool for obtaining new scientific data. In this article, we represent the widest information on the characteristics of fruit parts which can be investigated on fresh or fixed material by microscopy procedure. We submitted the guidelines on preparation of the material for study, using the microtechnique, histochemistry, and microscopy, the consequence of drafting the description, as also, as a list of the examined fruit parts on studied material, i. e. occurrence of this part and its features. In the description, we propose to compose the data in that order: exomorphic fruit characteristics, micromorphology and anatomy of the fruit, and mode of fruit disintegration. Exomorphic fruit characteristics comprise localization, form, size, color, surface, pubescence, of the fruit parts, their abscission after anthesis, and other features. The characteristics of the peduncle, fruit coverings, fruiting receptacle, fruiting ovary, style, and the other fruit parts were considered. Micromorphology of the fruit comprises the study of the inner ovary structure, detected by the anatomic and microscopic methods, on the sectioned fruit, presented on the temporary or permanent slides, particularly: the number and form of locules, the structure of septae, central column, placentae, seeds, as also vertical zonality of the gynoecium. The general anatomy of the fruit is described as stem or leaf anatomy, depending on the identity of the fruit part as the axis (receptacle) or phyllome (carpel). The vascular anatomy of the fruit is characterized as a part of the nodal structure of the receptacle, as follows: the formation of carpel and ovule traces, the number, type, and localization of vascular bundles in the fruit parts. The structural traits of fruit disintegration involve differentiation of the separation layers, mechanical tissues, and grooves along the lines of upcoming dehiscence, splitting, or abscission of the fruit. The awareness of the detailed record of morpho-anatomic characteristics of the fruit makes it possible to reveal the features, which are at the first time observed in the object under study, and which potentially can be used for taxonomy, evolutionary morphology, and the other fields of plant science.

CFD Numerical Simulation on the Mode of Ligament Disintegration during Centrifugal Granulation of Molten Slag by Using a Spinning Cup

In order to study the behavior of molten blast furnace slag ligament breakup into droplets by centrifugal granulation with a spinning cup, three-dimensional transient CFD model simulations were performed in the present work to study the process of the slag deformation into ligaments upon leaving the spinning cup, which eventually disintegrate into droplets. The formation of molten slag ligaments at the edge of the spinning cup and their disintegration into droplets were numerically revealed so that the behavior and mechanism of the slag ligament breakup into droplets could be investigated. This work specifically examined the influence of cup spinning speed on the diameter and length of the molten slag ligaments around the cup periphery and the diameter of the droplets produced. The simulation results show that, for the same slag flowrate, with the increase in cup spinning speed, the slag film thickness at the cup edge decreases, the number of molten slag ligaments increases, and the diameter of the ligaments decreases, thus reducing the diameter of slag droplets. Moreover, as the number of molten slag ligaments increases as a result of the increased cup spinning speed, the flowrate of a single ligament decreases, so that the ligament disintegrates in a shorter radial distance, that is, the length of the ligament is shortened. In addition, this work also investigated the behavior and mechanism of a single molten slag ligament breakup into droplets. It was found that the process of molten slag ligament breakup into droplets under the action of centrifugal force and surface tension can also be approximately explained by the theory of the Rayleigh disintegration mechanism.

CFD Modeling and Cold Physical Model Simulation on Single Molten Slag Ligament Disintegration into Droplets

Aiming at the mode of liquid ligament disintegration into droplets in the process of the centrifugal granulation of molten blast furnace slag using a spinning cup, in order to gain an in-depth understanding of the behavior and mechanism of droplet formation by liquid ligament disintegration and to obtain appropriate conditions to control the size of the produced slag granules, a three-dimensional CFD model describing water–air two-phase flow with a free surface was established in this work for simulating the process of a single water ligament breakup into droplets under the action of gravity, surface tension and inertial forces, so as to compare with the process of a molten slag ligament disintegration into droplets due to centrifugal force exerted by the spinning cup. By studying the disintegration behavior and mechanism of a single water ligament, the similar phenomenon of a molten slag ligament disintegration is examined. The numerical simulation results on the breakup of a single water ligament show that the length of the ligament before its disintegration and the diameter of the droplets formed both increase with the increase of the velocity of the ligament initially exiting a capillary nozzle. In addition, an experimental set-up was established in the laboratory to conduct cold physical model simulation experiments on single water or liquid paraffin ligament disintegration. The experimental results are compared with the numerical simulation results so that the reliability of the CFD model is verified. The results of the present study show that, in the centrifugal granulation process of blast furnace slag using a spinning cup operated in the ligament disintegration mode, the breakup of a single molten slag ligament is very similar to that of a single water or liquid paraffin ligament, and both approximately follow the Rayleigh Disintegration Mechanism, which provides a theoretical basis for analyzing the breakup process of the ligaments of different liquids as references for guiding the operation of centrifugal granulation of molten slag.

Distinct mode of membrane interaction and disintegration by diverse class of antimicrobial peptides

The exploitation of conventional antibiotics in conjunction with the adeptness of microbes has led to the emergence of multi-drug-resistant pathogens. This has posed a severe threat to combating life-threatening infectious diseases. Antimicrobial peptides (AMP), which are considered to be the first line of defense in all living organisms, are being developed for therapeutic use. Herein, we determined the NMR solution structure of Rhesus macaque Myeloid Alpha Defensin-4 (RMAD4), a defensin AMP. Additionally, the distinct modes of membrane perturbation for two structurally dissimilar classes of AMPs was studied using biophysical methods namely, Solid-state 31P NMR, DSC and cryo-TEM. The cathelicidin - Bovine myeloid antimicrobial peptide (BMAP-28 (1–18)), which adopts a helical conformation, and the defensin RMAD4 peptide that natively folds to form β-sheets appeared to engage differently with the bacterial membrane. The helical BMAP-28 (1–18) peptide initiates lipid segregation and membrane thinning followed by pore formation, while the β-stranded RMAD4 peptide demonstrates fragmentation of the bilayer by the carpet or detergent-like mechanism of action. Molecular dynamics studies sufficiently corroborated these findings. The structure and mechanism of action of the AMPs studied using experimental and computational approaches are believed to help in providing a platform for the rational design of new competent and cost-effective antimicrobial peptides for therapeutic applications.

The starting mechanism study on rainfall-induced sloop loose source in strong earthquake area

The 5.12 Wenchuan earthquake in 2008 led to a large number of loose deposits on the slope on both sides of the gully in the formation area. Under the triggering action of heavy rainfall, the previously unrecognized slope loose source in formation areas easily failed and started earlier than the overall start of the gully debris flow, which has practical significance for realizing the early warning of the gully debris flow starting. The special loose source conditions and postearthquake geological environment change the hydraulic mechanism of traditional debris flow start-up, which brings great difficulties to the monitoring and early warning of postearthquake debris flows. Therefore, based on hydraulics, on the premise of building a hydraulic model of groundwater level change of loose slope accumulation body, the characteristics and rules of groundwater level change are analyzed with the aid of hydraulic seepage theories, and the action characteristics of hydrodynamic pressure and hydrostatic pressure on the accumulation body are quantitatively studied. Based on field exploration data and average slope gradient, we divided the accumulation body in a reasonable manner; completed the sliding force, anti-sliding force and residual-sliding force mechanical expression and establishment; and performed a slope stability analysis. The research results show that the slope starting mode is divided into the thrust-type landslide and the retrogressive landslide mode of the subsection disintegration. The hydraulic deposit mechanism analytical results can also reverse the critical rainfall condition of slope failure. Finally, taking the Yindongzi gully in Dujiangyan as an example, the hydraulic mechanism of typical slope deposits in the formation area was analyzed and combined with the historical debris flow events in the study area to verify the physical simulation test, which was consistent with the field investigation results after the disaster.

Surface Topography Analysis of Mg-Based Composites with Different Nanoparticle Contents Disintegrated Using Abrasive Water Jet.

This study investigated the effect of abrasive water jet kinematic parameters, such as jet traverse speed and water pressure, on the surface of magnesium-based metal matrix nanocomposites (Mg-MMNCs) reinforced with 50 nm (average particle size) Al2O3 particles at concentrations of 0.66 and 1.11 wt.%. The extent of grooving caused by abrasive particles and irregularities in the abrasive waterjet machined surface with respect to traverse speed (20, 40, 250 and 500 mm/min), abrasive flow rate (200 and 300 g/min) and water pressure (100 and 400 MPa) was investigated using surface topography measurements. The results helped to identify the mode of material disintegration during the process. The nanoindentation results show that material softening was decreased in nanocomposites with higher reinforcement content due to the presence of a sufficient amount of nanoparticles (1.11 wt.%), which protected the surface from damage. The values of selected surface roughness profile parameters—average roughness (Ra), maximum height of peak (Rp) and maximum depth of valleys (Rv)—reveal a comparatively smooth surface finish in composites reinforced with 1.11 wt.% at a traverse speed of 500 mm/min. Moreover, abrasive waterjet machining at high water pressure (400 MPa) produced better surface quality due to sufficient material removal and effective cleaning of debris from the machining zone as compared to a low water pressure (100 MPa), low traverse speed (5 mm/min) and low abrasive mass flow rate (200 g/min).

Electric field induced dynamics of viscoplastic droplets in shear flow

We investigate the dynamics of viscoplastic droplets under the combined action of electric field and shear flow by performing direct numerical simulations. The electro-hydrodynamic equations are solved in a two-dimensional finite volume framework, and the interface is captured using a volume-of-fluid approach. The rheology of the viscoplastic droplet is modeled as a Bingham plastic fluid. Both the drop and the surrounding medium are considered to be perfect dielectric fluids. The simulations reveal that in the sole presence of the shear flow, the plasticity of the fluid plays a pivotal role in deciding the magnitude of droplet deformation and orientation. The local viscosity inside the drop is significantly augmented for higher plasticity of the fluid. Under the action of the electric field, the droplet deformation and orientation can be suitably tuned by varying the magnitude of the permittivity contrast between the fluids. The droplets experience enhanced deformation and preferred orientation against the flow direction when the permittivity ratio is greater than unity. Increasing the droplet plasticity leads to reduction in the droplet deformation. Conversely, by increasing the electric field strength, the deformation of the droplets can be notably enhanced, with a stronger response observed for a permittivity ratio beyond unity. Finally, it is observed that by suitably manipulating the strength of the shear flow and the electric field, droplet breakup can be engendered. The mode of droplet disintegration differs due to variation of the parameters, which can be attributed to the competing influence of shear and electric forces on the droplet.

Discrete element method modelling of impact breakage of ellipsoidal agglomerate

ABSTRACT Breakage of cereal grains approximated ellipsoidal shape such as rice and wheat kernel is an extremely common phenomenon for harvest and post-harvest processing in food industries. Unfortunately, there are few investigations about the breakage of cereal grains neither by means of experiment nor simulation methods. Moreover, it is of importance to understand the breakage mechanisms of cereal grains for controlling the final product quality. In this regard, this paper is to apply the discrete element method (DEM) combining bonded particle model (BPM) for simulating impact breakage of rice kernel and revealing its breakage characteristics. The rice kernel was represented as agglomerate composed of a set of mono-size primary spherical particles connected by ideal elastic solid bonds. Parameters characterizing strength of agglomerate were calibrated by comparing force-displacement curves from the uniaxial compression test. The critical impact velocities corresponding to the critical breakage state during the milling were compared through the theoretic, experimental and simulated methods. The effects of impact velocity represented the strength of impact and moisture content characterized the strength of agglomerate on its breakage behaviors, including damage ratio and size ratio of the largest fragment were analyzed. The results indicate that according to the change in breakage extent with impact velocity, breakage pattern can be divided into four modes. For the mode of local disintegration, the damage ratio and size ratio of the largest fragment change linearly with the impact velocity and moisture content, whereas for the mode of fragmentation the damage ratio and size ratio of the largest fragment vary exponentially with the impact velocity and moisture content. Furthermore, the relationship between difference in kinetic energy and damage ratio fits the linear function well for the mode of local disintegration, whereas it fits the Exp3p2 exponential function well for the mode of fragmentation. The findings are useful for providing theoretic guidance to the study on the impact breakage of other cereal grains and the revelation of breakage mechanism in a rice mill.

Numerical Study on Zonal Disintegration of Deep Rock Mass Using Three‐Dimensional Bonded Block Model

Zonal disintegration, a phenomenon of fractured zones and intact zones distributed alternately in deep rock mass, is different from the excavation‐damaged zone of shallow rock mass. In this study, bonded block model of 3DEC was employed to study the fracture mode and origination condition of zonal disintegration. Initiation, propagation, and coalescence progress of fracture around the roadway boundary under different triaxial stress conditions are elaborated. Numerical simulation demonstrated that zonal disintegration may occur when the direction of maximum principal stress is parallel to the roadway axis. It is interesting to find that the fracture around the roadway boundary traced the line of a spiral line, while slip‐line fractures distributed apart from the roadway boundary. The extent of the alternate fracture zone decreased as the confining pressure increased, and alternate fracture zone was no longer in existence when the confining pressure reaches a certain value. Effects of roadway shape on zonal disintegration were also studied, and the results indicated that the curvature of the fracture track line tends to be equal to the roadway boundary in shallow surrounding rock of the roadway, while the fractures in deep surrounding rock seems unaffected by the roadway shape. Those findings are of great significance to support design of deep underground openings.

Explosive disintegration of two-component droplets in a gas flow at its turbulization

The experimental results shown that the mode of droplet disintegration dominates in the laminar flow, and the intensive fragmentation is prevalent in the turbulent flow during almost the entire time of heating. Typical dependences of the time of droplet heatup before disintegration or fragmentation on the temperature, flow rate, structure and regime (laminar and turbulent) are established. The studies are conducted with heated air and flue gases to ensure the application of the research results in the technology of thermal and flame cleaning of liquids from irregular impurities. It is shown that in the flow of combustion products the droplet disintegration occurs 15-20% faster than in the air-flow. In this case, the explosive puffing is more often realized. At high-temperatures (more than 400?C) the characteristics of the explosive droplet disintegration in the studied flows are almost identical (differences in disintegration times do not exceed 5% at different flow turbulization). At lower temperatures, the disintegration times differ 3-4 times for the range Re = 2200-3400. In this case, the more Reynolds number is, the more intense is the fragmentation of two-component droplets throughout the heating time. Due to explosive disintegration of intensely evaporating two-component droplets the growth of the relative area of evaporation was 10-25 times.

An explosive disintegration of heated fuel droplets with adding water

This work experimentally studies the processes of explosive disintegration of heated fuel droplets with variations of the added water volume. The studies are performed for typical liquid fuels burnt in power plants, as well as flammable liquids being the main fuel component: kerosene, diesel, gasoline, oil, turbine and automobile oil. The minimum (sufficient for the explosive breakup of droplets) heating temperature and the ratio of concentrations of water and flammable liquid are determined. The optical method of Planar Laser Induced Fluorescence (with the operation principle based on the laser illumination of a drop or a liquid film with the introduction of a fluorophore dye) is used to determine temperatures at the inter-component boundary that are sufficient for the micro-explosion of a two-liquid drop. The influence of laser action on the drop on the processes of its heating, evaporation, transformation and breakup is evaluated. The effect of the laser on the mode of explosive disintegration of droplets, the time of its heating and destruction, and the minimum (limiting) temperature of droplet disintegration is determined. Laser irradiation intensifies heating and breakup of fuel droplets as a result of three processes: an additional radiative heat flux; the perturbation (deformation) of the medium interface; and a considerable temperature gradient on the inter-component boundaries, leading to high velocity of convection flows and the formation of vortex structures in the vicinity of the medium interface. The technology of fuel droplets disintegration is proposed.

Experimental and numerical investigations of water jets

The determination of air entrainment in free falling water jets is still a topic subject to large uncertainties that eddy-viscosity model. The RANS turbulence model did not generate water separation from the water surface. However, the LES model was able to reproduce the strong dynamic interaction between the air-water phases and come from the strong interaction among independent parameters. Despite many findings on this topic about the determination of the water jet breakup length, a mathematical generalization has not been found yet and the hydraulic physical modelling of air-water faces limitations because of scale effects. As a consequence, a spray mode of disintegration of an experimental test was used to validate the results using computational fluid dynamics by means of two different turbulent approaches: 1) Reynolds Average Navier-Stokes RANS method, with the standard k-ε model, and 2) Large Eddy Simulation LES, with the one-equationthe breakup processes, but at an early stage.

Effect of deflocculation on photo induced thin layer titanium dioxide disintegration of dairy waste activated sludge for cost and energy efficient methane production

In the present study, the deflocculated sludge was disintegrated through thin layer immobilized titanium dioxide (TiO2) as photocatalyst under solar irradiation. The deflocculation of sludge was carried out by 0.05g/g SS of sodium citrate aiming to facilitate more surface area for subsequent TiO2 mediated disintegration. The proposed mode of disintegration was investigated by varying TiO2 dosage, pH and time. The maximum COD solubilization of 18.4% was obtained in the optimum 0.4g/L of TiO2 dosage with 5.5 pH and exposure time of 40min. Anaerobic assay of disintegrated samples confirms the role of deflocculation as methane yield was found to be higher in deflocculated (235.6mL/gVS) than the flocculated sludge (146.8mL/gVS). Moreover, the proposed method (Net cost for control – Net cost for deflocculation) saves sludge management cost of about $132 with 53.8% of suspended solids (SS) reduction.

Microchaete robinsonii sp.nov., a new heteropolar cyanoprokaryote (cyanophyte, cyanobacterium) from southern Manitoba, Canada

A new heteropolar nostocalean cyanoprokaryote Microchaete robinsonii sp.nov. is described from the benthic periphytic assemblage found on stones in the eutrophic Souris River near Dunclody in southwestern Manitoba, Canada. This species belongs to the group of species with narrow trichomes attenuated to the apex but never forming hairs. The morphology of this species is described and its taxonomic position within the genus Microchaete is presented. It differs from other Microchaete species by morphology of filaments, trichomes and sheaths, dimensions, mode of disintegration of trichomes into hormogonia, and its ecology. The morphological features of heteropolar nostocalean genera useful in generic delimitation are reviewed and discussed. Key words: cyanoprokaryotes, Microchaete, new species, rivers, periphyton, Canada.

Observations of Microscopic Structures of Diesel Sprays with a Nano-spark Light Source.

To elucidate the process of fuel-air mixture formation before ignition in diesel engines, it is important ot investigate the disintegration of fuel flow and droplet formation in intermittent sprays at the very early stage of injection. In this study, the microscopic structures of nonevaporating sprays up to 0.5 ms from the start of injection are studied using photographs with high time resolution, using a nanosecond spark light source. The results show that the fuel flows have very distinctive shapes just after the start of injection. Fragments of disintegrated fuel are observed even at 50 microseconds from the commencement of injection. Ambient pressure has a great effect on the mode of disintegration.

The elementary RNP fiber — not the higher order structure — determines the all-or-none disintegration behaviour of balbiani ring pre-messenger RNP particles upon RNase A treatment

Balbiani ring premessenger ribonucleoprotein (RNP) particles are built from a 7-nm RNP fiber which is tightly folded into a ring-shaped RNP ribbon. Isolated particles are known to disintegrate in all-or-none fashion upon RNase A treatment. In the present study we investigated whether this mode of disintegration is dependent on an intact particle structure or is inherent in the 7-nm fiber. When treated at low ionic strength, the Balbiani ring (BR) particles lost their higher order structure and the 7-nm fiber was unpacked, as evidenced by sucrose gradient sedimentation and electron microscopy. When treated with RNase A, unfolded as well as intact particles disintegrated in the all-or-none fashion, with similar kinetics and without apparent intermediates. Proteinase K treatment, however, obliterated this pattern: the protein-free particle RNA degraded progressively. As the typical disintegration pattern of the particles was not altered by unfolding, but was lost by deproteinization, the all-or-none mode of disintegration is likely to be a property of the 7-nm RNP fiber.

Anionic polymerization using rotating disk reactor (I)

AbstractAnionic polymerization of styrene with sodium naphthalene was carried out using the rotating disk reactor. The mode of disintegration of the polymerization mixture changed from dropwise to filamentwise and finally to filmwise within a few minutes of reaction at low speed revolution and a large amount of flow. Under the condition of high speed revolution and a small amount of flow, only dropwise disintegration was observed and a beadlike polymer was obtained having a unimodal molecular weight distribution. The polymer was found to have a bimodal distribution when the polymerization was terminated on the rotating disk. These results are explained by assuming that a highly viscous layer was formed near the disk surface.

Particle‐Size Distribution Characterization for the Coarse Fraction of a Granite Soil: II. Disintegrating Granite

AbstractThe object of this study was to test the incomplete gamma function previously developed as a descriptor for grapite disintegration. Samples of disintegrating granite were taken from several sites at three locations in a hot semiarid environment in south‐central Africa (southern Rhodesia). These samples were from surface rock, profile corestones, and disintegrating rock at the base of the soil profile. Particlesize distributions were obtained using the standard sieving and pipette method. For materials > 10 mm, Martin's diameter was measured directly.The incomplete gamma function was fitted to these data, and also to U.S. and French data from the literature, for granite in an apparently similar state of disintegration. The values for the degree‐of‐disintegration parameter were fairly uniform. The mode of disintegration appeared the same regardless of site. The two‐parameter incomplete gamma distribution was found to be a reasonably good descriptor of the particle‐size distribution of disintegrating granite. The mean size appeared to be a sensitive and useful single‐valued descriptor for these distributions.

Disintegration of dung pads in north Queensland before the introduction of exotic dung beetles

Before the liberation of exotic dung beetles, marked dung pads at two different sites in north Queensland were regularly observed to assess the time and mode of disintegration. Pads survived at least three months, and sometimes a year or more. Trampling by cattle and weathering broke up some pads, and others were destroyed by termites. In very wet conditions earthworms removed some old dung, but at no time were native dung beetles significant in pad breakup.

29] Guanylate cyclase in human platelets

Publisher Summary Human blood cells are separated by differential centrifugation and by use of Dextran. In plasma and homogenates of erythrocytes, no guanylate cyclase activity was detectable. In homogenates of mixed leukocytes (containing some platelets), the guanylate cyclase activity was about 50 pmoles min -1 mg protein -1 . The enzyme activity in platelets varied between 0.2 and 2.0 nmoles min -1 mg protein -1 this is substantially (up to an order of magnitude) higher than in any other mammalian tissue so far studied except outer segments of retinal rods. More than 90% of the total guanylate cyclase activity measured in subcellular fractions was found in the 250,000 g, 60-minute supernatant fluid. The apparent distribution of guanylate cyclase between particulate and soluble fractions was not affected by the mode of cell disintegration. Unlike the particulate guanylate cyclase activity from a number of other sources, that in platelets was not increased by Triton X-100. The enzyme in platelet homogenates or high speed supernatant fractions was inhibited by 50% by about 1 mg/ml of Triton X-100 in the incubation medium.