Spherical Granules Research Articles

Structural, thermal, and rheological properties of starches isolated from four different varieties of Indian barnyard millet ( Echinochloafrumentacea )

The present study explored the properties of starches isolated from four different Indian varieties of barnyard millet. The amylose content ranged from 21.27 to 23.30% (db) and was highest for BMV2 (23.30%). The swelling power of millet starch varied from 2.10 to 18.80, while solubility ranged from 1.30 to 14.20. The peak viscosity (2492 RVU), the final viscosity (3832 RVU), and the setback viscosity (2077 RVU) were the highest for BMV3 as compared to that of other starches. The starches exhibited small spherical, large angular, and large spherical granules with A-type crystallinity and an average size of around 10 μm. The degree of crystallinity ranged from 25.7% (for BMV4) to 31.6% (for BMV1). The strong absorption bands from 3255 to 3260 cm−1 were attributed to –OH stretching of the polysaccharide skeleton. A higher yield and purity value suggests that barnyard millet starch can be exploited for commercial starch utilization. Practical applications Starch is the major component of barnyard millet grain. It can be isolated, modified, and used as a relatively cheap and novel source. The potential of native and modified starch in food, as well as non-food industry, can be further exploited. Since the amylose content of barnyard millet starch is high, it can be employed in preparing biodegradable films in combination with a suitable plasticizer.

Study of a Highly Porous Composite Material Based on an Aluminum Matrix with an Ordered Cellular Structure Formed by Hollow Copper–Graphite Spherical Granules

Study of a Highly Porous Composite Material Based on an Aluminum Matrix with an Ordered Cellular Structure Formed by Hollow Copper–Graphite Spherical Granules

The porous coating of joint implants as a factor of their stable fixation

To ensure effective biological fixation of the newly designed cementless hip joint implant, a macroporous material proposed to be used as a coating for the implant was studied. Eighty-five samples of the cylindrical implants produced via hot sintering from spherical titanium granules having different diameters were analyzed. Morphological, mechanical, and other findings revealed a rapid bone ingrowth into the sample pores and their firm biological fixation in the canine tubular bone. The selected material having optimal characteristics will be applied to the surface of the specially designed joint implant. Its pilot-designed model is manufactured to make initial clinical trials, followed by updating for applying the ball coating. The new joint implant macroporous coating with its improved geometry will enhance the fixation of the construction due to bone ingrowth, contribute to the rapid postoperative recovery of a patients full-load walking ability, and minimize the risk for aceptic loosening of the implant.

Microstructure of spherical granules based on hydroxyapatite and wollastonite

Spherical granules are one of the preferred forms of biomaterials for bone defects healing. Chemical composition and microstructure of these materials are largely determines their behavior in vivo. Synthesis and properties investigation of polydispersed porous composite granular materials containing several bioactive components are the important task of modern biomedical chemistry. In this work, the microstructure of organomineral granules based on hydroxyapatite, wollastonite, and gelatine, and the products of their calcination were studied. It was found that as a result of removal of the polymer binder from the ceramic particles surface, nanopores were disclosed, and the subsequent crystallites sintering provide the granules shape stability.

Experimental Investigation of the Solid Conveying Behavior of Smooth and Grooved Single-Screw Extruders at High Screw Speeds.

Single-screw extrusion at high screw speeds is established nowadays since it allows for a high mass throughput at a comparatively small extruder size. Compared to conventional extrusion at low screw speeds, a considerable non-linearity in mass throughput appears by exceeding a certain threshold screw speed. In this study, the solid conveying behavior of different plastic granules with varying geometries was investigated in a smooth, a helically and an axially grooved solid conveying zone for screw speeds up to 1350 rpm. These experimental findings are compared to classical analytical predictions in the literature. It is found for the first time that both the shape and size of the plastic granules play a decisive role in determining the threshold screw speed at which a non-linear mass throughput is observed. It is shown that small and spherical granules exhibit a later onset of non-linear throughput compared to larger lenticular and cylindrical shaped granules. Moreover, it is revealed that the mass throughput equalizes for an axially and a helically grooved solid conveying zone at high screw speeds. This is contrary to the low screw speed range where the axially grooved barrel results in a significantly higher throughput than the helically grooved barrel. Thus, the maximum throughput at high screw speeds is limited by the granule stream provided by the hopper opening and is no longer governed by the groove angle.

Host casein kinase 1-mediated phosphorylation modulates phase separation of a rhabdovirus phosphoprotein and virus infection.

Liquid-liquid phase separation (LLPS) plays important roles in forming cellular membraneless organelles. However, how host factors regulate LLPS of viral proteins during negative-sense RNA (NSR) virus infection is largely unknown. Here, we used barley yellow striate mosaic virus (BYSMV) as a model to demonstrate regulation of host casein kinase 1 (CK1) in phase separation and infection of NSR viruses. We first found that the BYSMV phosphoprotein (P) formed spherical granules with liquid properties and recruited viral nucleotide (N) and polymerase (L) proteins in vivo. Moreover, the P-formed granules were tethered to the ER/actin network for trafficking and fusion. BYSMV P alone formed droplets and incorporated the N protein and the 5' trailer of genomic RNA in vitro. Interestingly, phase separation of BYSMV P was inhibited by host CK1-dependent phosphorylation of an intrinsically disordered P protein region. Genetic assays demonstrated that the unphosphorylated mutant of BYSMV P exhibited condensed phase, which promoted viroplasm formation and virus replication. Whereas, the phosphorylation-mimic mutant existed in diffuse phase state for virus transcription. Collectively, our results demonstrate that host CK1 modulates phase separation of the viral P protein and virus infection.

ИМПУЛЬСНО-УДАРНАЯ ОБРАБОТКА СУЖАЮЩИХСЯ МЕЖЛОПАТОЧНЫХ КАНАЛОВ

The methodology and technological support of the specified parameters of the surface of a narrow narrowing channel with a twist along the radius and the regulations for the design of combined pulse-force hardening operations have been created, a new patentable techno-logical process for strengthening narrow nar-rowing curved channels by combined pulse-shock action with the promotion of a free tool (spherical granules) in low-frequency oscilla-tion conditions has been developed.

Achieving robust nitritation in a modified continuous-flow reactor: From micro-granule cultivation to nitrite-oxidizing bacteria elimination

In this study, a modified continuous-flow nitrifying reactor was successfully operated for rapid cultivation of micro-granules and achieving robust nitritation. Results showed that sludge granulation with mean size of ca. 100 µm was achieved within three weeks by gradually increasing settling velocity-based selection pressure from 0.48 to 0.9 m/hr. Though Nitrospira like nitrite-oxidizing bacteria (NOB) were enriched in the micro-granules with a ratio between ammonia-oxidizing bacteria (AOB) and NOB of 5.7%/6.5% on day 21, fast nitritation was achieved within one-week by gradually increasing of influent ammonium concentration (from 50 to 200 mg/L). Maintaining ammonium in-excess was the key for repressing NOB in the micro-granules. Interestingly, when the influent ammonium concentration switched back to 50 mg/L still with the residual ammonium of 15–25 mg/L, the nitrite accumulation efficiency increased from 90% to 98%. Experimental results suggested that the NOB repression was intensified by both oxygen and nitrite unavailability in the inner layers of micro-granules. Unexpectedly, continuous operation with ammonium in excess resulted in overproduction of extracellular polysaccharides and overgrowth of some bacteria (e.g., Nitrosomonas, Arenimonas, and Flavobacterium), which deteriorated the micro-granule stability and drove the micro-granules aggregation into larger ones with irregular morphology. However, efficient nitritation was stably maintained with extremely high ammonium oxidation potential (> 50 mg/g VSS/hr) and nearly complete washout of NOB was obtained. This suggested that smooth and spherical granule was not a prerequisite for achieving NOB wash-out and maintaining effective nitritation in the granular reactor. Overall, the micro-granules exhibited a great practical potential for high-rate nitritation.

Fine Structure of the Visual System of Arge similis (Hymenoptera, Argidae).

Simple SummaryArge similis is a notorious pest on rhododendron plants. The fine structure of the compound eyes of A. similis adults were examined by light, scanning, and transmission electron microscopy. Each ommatidium consists of a lamellated cornea, a crystalline cone with eucone type, and a centrally fused rhabdom composed of eight retinular cells.External morphology and ultrastructure of the visual system of Arge similis (Vollenhoven, 1860) adults were investigated by light microscopy, scanning electron microscopy, and transmission electron microscopy. Each compound eye contains 2022 ± 89 (mean ± SE) facets in males and 2223 ± 52 facets in females. Arge similis has an apposition kind of compound eye composed of a cornea, a crystalline cone of four cone cells, and a centrally fused rhabdom made up of the rhabdomeres of eight large retinular cells. Each crystalline cone is surrounded by primary and secondary pigment cells with black spherical screening pigment granules measuring 0.60 ± 0.02 and 0.41 ± 0.01 μm in diameter, respectively. Based on our findings, the compound eye of A. similis can be expected to exhibit high adaptability to light intensity changes.

Preparation of spin coated PbS thin films using bis-tetrahydroquinolinedithiocarbamatolead(II) complex as a single source precursor

Recently, the incorporation of single-source molecular precursors in synthetic protocols has been identified as an effective and easy route toward tuning the sought-after properties of thin films. In this work, bis-tetrahydroquinolinedithiocarbamato complex of lead(II) has been used as a single-source molecular precursor to deposit PbS thin films at elevated temperatures. The spin coating method was chosen as a deposition technique to afford PbS thin films. The morphology of the obtained films was observed to be influenced by the variation of temperature. Formations of compact thick and agglomerated spherical granules were observed at a lower temperature whereas elevated temperatures afforded the formation of cubic and multipodal shaped structures. From the energy dispersive X-ray spectroscopy (EDS) results, the elemental ratio of the finally formed films agree with the PbS composition. X-ray diffraction studies further revealed the formation of the crystalline cubic phase of PbS films with a calculated crystallite size in the range of 50 − 58 nm.

Mathematical modelling of thermal microexplosion in a catalyst granule with point sources of heat release

A mathematical model of heat and mass transfer in a spherical catalyst granule is proposed. Exothermic synthesis reactions are carried out on point active centres located inside a porous ceramic granule. From the surface of the granule the heat of catalytic reactions is removed into liquid synthesis products. The rate of a chemical reaction is modelled by a modified Arrhenius law. In contrast to the homogeneous model of a catalytic granule methods for calculating heat transfer processes in a system of point, active centres do not develop. An iterative procedure is suggested to calculate the unknown temperature and concentration of the reagent at the active centre. It is shown that the temperature of the active centres is significantly higher than in the volume of the granule. The results of modelling a thermal explosion with increasing granule size and reactor temperature are presented.

Моделирование особенностей магнитных свойств осесимметричных гранул жестких сверхпроводников II рода

Based on the equations of electrodynamics and the concept of a critical state for hard superconductors of the 2nd kind, numerical simulation of the magnetic properties of axisymmetric superconducting samples, in particular, granules, is performed for a number of models of the dependence of the critical current density on the magnetic field induction. The magnetic moment loops are calculated directly by integrating the integral equation for the current density over time. The phenomena of the peak effect and the asymmetry of the magnetization hysteresis loop are also considered using the indicated equation. Various versions of the functions used in the literature were used as peak functions. In addition to the hysteresis loop of the magnetic moment, the magnetic field induction at the center of axisymmetric samples, and the total penetration field, the profiles of the critical current density Jc(B) and the equilibrium magnetic moment for spherical granules were obtained. The method used for calculating the magnetic moment of superconductors makes it possible to take into account the equilibrium and nonequilibrium regions of the magnetization of the samples independently.

ПОЛУЧЕНИЕ СФЕРИЧЕСКИХ ГРАНУЛ ВЫСОКОТЕМПЕРАТУРНОГО МЕТАЛЛИЧЕСКОГО КОМПОЗИЦИОННОГО МАТЕРИАЛА НА ОСНОВЕ МОЛИБДЕНА

Discusses the process of obtaining spherical granules of a metal composite material based on molybdenum with an initial fraction of 40‒63 microns. The results obtained during the research showed the fundamental possibility of spheroidization of granules of high-temperature metal composite materials based on refractory metals reinforced with particles of ceramic compounds. However, the need for a more thorough study and selection of spheroidization modes to minimize the formation of satellites on granules during processing in an electric arc discharge plasma is revealed.

Simulation of the features of the magnetic properties of axisummetric granules of hard type II superconductors

Based on the equations of electrodynamics and the concept of a critical state for hard superconductors of the 2nd kind, numerical simulation of the magnetic properties of axisymmetric superconducting samples, in particular, granules, is performed for a number of models of the dependence of the critical current density on the magnetic field induction. The magnetic moment loops are calculated directly by integrating the integral equation for the current density over time. The phenomena of the peak effect and the asymmetry of the magnetization hysteresis loop are also considered using the indicated equation. Various versions of the functions used in the literature were used as peak functions. In addition to the hysteresis loop of the magnetic moment, the magnetic field induction at the center of axisymmetric samples, and the total penetration field, the profiles of the critical current density Jc(B) and the equilibrium magnetic moment for spherical granules were obtained. The method used for calculating the magnetic moment of superconductors makes it possible to take into account the equilibrium and nonequilibrium regions of the magnetization of the samples independently Keywords: magnetic moment, axisymmetric granules, type II superconductor, critical state, peak effect, equilibrium magnetic moment.

Study of Effect of Substrate Temperature on Structure, Morphology and optical Properties of Spray Deposited Cu2ZnSnS4 Nano Thin films.

Cu2ZnSnS4 (CZTS) films for different substrate temperatures were deposited by using simple chemical spray technique. Analytical reagent Grade; Copper chloride (CuCl2), Zinc chloride (ZnCl2), Tin chloride (SnCl4.5H2O) and thiourea (SC(NH2)2) were used as Cu+, Zn+, and Sn+ and ion sources respectively. A set of five CZTS films was deposited using five different substrate temperatures (175, 200, 250, 275, and 300 ). The structure, Morphology, Elemental analysis and optical properties of these films were studied using X-ray diffratometer (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDX) and UV-Visible spectroscopy techniques respectively. The XRD spectra showed that all films are polycrystalline and exhibit kesterite tetragonal crystal structure with preferential orientation along (112) direction. The crstallinity was found increased with substrate temperature. The calculated crystallite size was increased with increase in substrate temperature. The surface morphology of CZTS films was improved with increase in substrate temperature. The film sample deposited for 275 represent excellent spherical granules CZTS crystals of increasing size from 640 nm to 1.8 μm arranged in regular fashion with some void spaces. The purity of the composition was investigated using Elemental analysis of the deposited films. The optical band gap was estimated using Tauc plots. The band gap obtained was to be in the range of 1.4 to 1.6 eV.

Получение сфер на основе NiO с использованием катионитов с гелевой и макропористой структурами

The article discusses the production of materials based on nickel oxide in the form of spherical granules ranging in size from 300 to 700 nm, by the method of thermal destruction of cation exchangers with gel (TOKEM-100)and macroporous (TOKEM-250) structures saturated with nickel (II) ions. Thermal analysis was used to establish the temperature regimes of annealing of Ni2+–ТОКЕМ-250 и Ni2+–ТОКЕМ-100 samples. The prepared materials were investigated by XRD and SEM. The use of TOKEM-100 cation exchanger makes it possible to obtain samples with spherical granules based on trigonal nickel (II) oxide, characterized by a sintered surface morphology. The use of TOKEM-250 cation exchanger leads to the formation of spheres based on NiO cubic modification with an inhomogeneous surface morphology.

Mathematical Model of the Deaeration of Finely Dispersed Solid Media in a Spherical Matrix of a Roller-Type Apparatus

The additional operation of deaeration (compaction) of powders affects the quality of many products of chemical industries, the conditions for their delivery. Otherwise, energy consumption increases significantly. The aim of this work is the modeling of the deaeration of solid finely dispersed media in a gap with perforated hemispherical shapes on the surfaces of the shaft and conveyor belt within the framework of the mechanics of heterogeneous systems. A plane-deformation model is described, neglecting the forces of interphase interaction and taking into account the compressibility of a solid-particle-gas mixture without elastoplastic deformations. The model assumes consideration of the movement of (1) the components of the solid skeleton together with the carrying phase as a whole; (2) gas in an isothermal state through the pores of a finely dispersed material. This work is devoted to the study of part (a), i.e., behavior of the solid particle-gas system as a whole. The efficiency of the seal-deaerator is estimated using the obtained analytical dependencies for the main strength and speed indicators. The change in the degree of compaction of a spherical granule made of kaolin with given strength characteristics is investigated. It is shown that for the initial time interval up to 3.7⨯10−2 s, the growth of the porosity value relative to the horizontal coordinate along the conveyor belt is exponential and increases by a factor of 1.1. After eight such time intervals, the porosity values stabilize along the indicated coordinate with an increase of more than 1.4 times from the initial value.

Systematic Study of the Effects of High Shear Granulation Parameters on Process Yield, Granule Size, and Shape by Dynamic Image Analysis.

The aim of the work was to analyze the influence of process parameters of high shear granulation on the process yield and on the morphology of granules on the basis of dynamic image analysis. The amount of added granulation liquid had a significant effect on all monitored granulometric parameters and caused significant changes in the yield of the process. In regard of the shape, the most spherical granules with the smoothest surface were formed at a liquid to solid ratio of ≈1. The smallest granules were formed at an impeller speed of 700 rpm, but the granules formed at 500 rpm showed both the most desirable shape and the highest process yield. Variation in the shape factors relied not only on the process parameters, but also on the area equivalent diameter of the individual granules in the batch. A linear relationship was found between the amount of granulation liquid and the compressibility of the granules. Using response surface methodology, models for predicting the size of granules and process yield related to the amount of added liquid and the impeller speed were generated, on the basis of which the size of granules and yield can be determined with great accuracy.

Increasing the Adherence of Metallic Copper to the Surface of Titanium Hydride

Studies have been carried out to increase the adhesive interaction between a titanium hydride substrate and a copper coating. An additional layer containing chemically active groups was created on the surface of the spherical titanium hydride by chemisorption modification. This paper discusses the results of scanning electron microscopy (SEM) using energy-dispersive X-ray spectroscopic mapping of coatings obtained on spherical granules of titanium hydride before and after adsorption modification. The mechanism of interaction of the surface of spherical granules of titanium hydride and titanium sulfate salt is proposed. It is shown that the creation of a chemisorbed layer of hydroxotitanyl and the subsequent electrodeposition of metallic copper contribute to the formation of a multilayer shell of a titanium–copper coating on the surface of spherical titanium hydride granules (≡Ti-O-Cu-) with a high adhesive interaction. Results have been given for an experimental study of the thermal stability of the initial spherical granules of titanium hydride and granules coated with a multilayer titanium-copper shell.

Bone regeneration capacity of newly developed spherical magnesium phosphate cement granules

ObjectivesMagnesium phosphate–based cements begin to catch more attention as bone substitute materials and especially as alternatives for the more commonly used calcium phosphates. In bone substitutes for augmentation purposes, atraumatic materials with good biocompatibility and resorbability are favorable. In the current study, we describe the in vivo testing of novel bone augmentation materials in form of spherical granules based on a calcium-doped magnesium phosphate (CaMgP) cement.Materials and methodsGranules with diameters between 500 and 710 μm were fabricated via the emulsification of CaMgP cement pastes in a lipophilic liquid. As basic material, two different CaMgP formulations were used. The obtained granules were implanted into drill hole defects at the distal femoral condyle of 27 New Zealand white rabbits for 6 and 12 weeks. After explantation, the femora were examined via X-ray diffraction analysis, histological staining, radiological examination, and EDX measurement.ResultsBoth granule types display excellent biocompatibility without any signs of inflammation and allow for proper bone healing without the interposition of connective tissue. CaMgP granules show a fast and continuous degradation and enable fully adequate bone regeneration.ConclusionsDue to their biocompatibility, their degradation behavior, and their completely spherical morphology, these CaMgP granules present a promising bone substitute material for bone augmentation procedures, especially in sensitive areas.Clinical relevanceThe mostly insufficient local bone supply after tooth extractions complicates prosthetic dental restoration or makes it even impossible. Therefore, bone augmentation procedures are oftentimes inevitable. Spherical CaMgP granules may represent a valuable bone replacement material in many situations.