scholarly journals Reduction of Core-loss in the High Frequency Band of the Fe-Si-Cr Crystalline Alloy According to Particle Size

2021 ◽  
Author(s):  
Yeon Jun Choi ◽  
Ji Hun Ahn ◽  
Deok Hyeon Kim ◽  
Ye Rae Kim ◽  
Bo Wha Lee
Keyword(s):  
Particle Size ◽  
High Performance ◽  
Raw Materials ◽  
Core Loss ◽  
Magnetic Saturation ◽  
Magnetic Composites ◽  
Performance Requirements ◽  
Materials Used ◽  
Average Size ◽  
The Relationship

Abstract In order for soft magnetic composites (SMCs) to achieve the high-performance requirements expected of them even at high frequencies, high permeability and low core-loss are required. In this study, we used different sizes of gas atomized Fe-Si-Cr alloy powder to produce SMCs, this alloy has higher resistivity than existing materials used in SMCs such as Fe-Si alloy or pure Fe. These powders were prepared by sieving raw materials which had an average size from less than 25 µm to over 63 µm. Our experiments show that as particle size decreases, the magnetic saturation tends to increase, the sample made from the powder with particles 25-38 µm in size recorded the highest magnetic saturation of 169.38 emu/g. Additionally, as particle size decreased, permeability increased. The sample made from powder with particles under 25 µm had a permeability of 20.7 H/m at 1 MHz. Also, the relationship between particle size and quality factor was found to be inversely proportional. Finally, the minimum core-loss was 187.26 kW/m3 at 1 MHz for the sample made from powder whose constituent particles are under 25 µm. We also observed that the core-loss is proportional to particle size.

scholarly journals Environmentally Friendly, High-Performance Fire Retardant Made from Cellulose and Graphite

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2400
Author(s):  
Leandra P. Santos ◽  
Douglas S. da Silva ◽  
Thais H. Morari ◽  
Fernando Galembeck
Keyword(s):  
High Performance ◽  
Raw Materials ◽  
Fire Retardant ◽  
Visual Observation ◽  
Flame Resistance ◽  
New Developments ◽  
New Class ◽  
New Material ◽  
Accredited Laboratory ◽  
Materials Used

Many materials and additives perform well as fire retardants and suppressants, but there is an ever-growing list of unfulfilled demands requiring new developments. This work explores the outstanding dispersant and adhesive performances of cellulose to create a new effective fire-retardant: exfoliated and reassembled graphite (ERG). This is a new 2D polyfunctional material formed by drying aqueous dispersions of graphite and cellulose on wood, canvas, and other lignocellulosic materials, thus producing adherent layers that reduce the damage caused by a flame to the substrates. Visual observation, thermal images and surface temperature measurements reveal fast heat transfer away from the flamed spots, suppressing flare formation. Pinewood coated with ERG underwent standard flame resistance tests in an accredited laboratory, reaching the highest possible class for combustible substrates. The fire-retardant performance of ERG derives from its thermal stability in air and from its ability to transfer heat to the environment, by conduction and radiation. This new material may thus lead a new class of flame-retardant coatings based on a hitherto unexplored mechanism for fire retardation and showing several technical advantages: the precursor dispersions are water-based, the raw materials used are commodities, and the production process can be performed on commonly used equipment with minimal waste.

Pots on mats: mat-impressed salt-extraction pottery at Chalcolithic Provadia-Solnitsata, Bulgaria

Antiquity ◽  
2021 ◽  
pp. 1-16
Author(s):  
Mila Andonova ◽  
Vassil Nikolov
Keyword(s):  
Material Culture ◽  
Large Scale ◽  
Raw Materials ◽  
Salt Production ◽  
Production And Consumption ◽  
Late Chalcolithic ◽  
South Eastern Europe ◽  
Materials Used ◽  
The Relationship

Evidence for both basket weaving and salt production is often elusive in the prehistoric archaeological record. An assemblage of Middle–Late Chalcolithic pottery from Provadia-Solnitsata in Bulgaria provides insight into these two different technologies and the relationship between them. The authors analyse sherds from vessels used in large-scale salt production, the bases of which bear the impression of woven mats. This analysis reveals the possible raw materials used in mat weaving at Provadia-Solnitsata and allows interpretation of the role of these mats in salt production at the site. The results illustrate how it is possible to see the ‘invisible’ material culture of prehistoric south-eastern Europe and its importance for production and consumption.

scholarly journals Determination of Chondroitin Sulfate Content in Raw Materials and Dietary Supplements by High-Performance Liquid Chromatography with UV Detection After Enzymatic Hydrolysis: Single-Laboratory Validation First Action 2015.11

2016 ◽  
Vol 99 (1) ◽  
pp. 53-54
Author(s):  
Sharon L Brunelle
Keyword(s):  
Chondroitin Sulfate ◽  
Dietary Supplements ◽  
High Performance ◽  
Raw Materials ◽  
Method Performance ◽  
Expert Review ◽  
Performance Requirements ◽  
Expert Review Panel ◽  
Single Laboratory

Abstract A previously validated method for determination of chondroitin sulfate in raw materials and dietary supplements was submitted to the AOAC Expert Review Panel (ERP) for Stakeholder Panel on Dietary Supplements Set 1 Ingredients (Anthocyanins, Chondroitin, and PDE5 Inhibitors) for consideration of First Action Official MethodsSM status. The ERP evaluated the single-laboratory validation results against AOAC Standard Method Performance Requirements 2014.009. With recoveries of 100.8–101.6% in raw materials and 105.4–105.8% in finished products and precision of 0.25–1.8% RSDr within-day and 1.6–4.72% RSDr overall, the ERP adopted the method for First Action Official Methods status and provided recommendations for achieving Final Action status.

Influence of Surface Area on the Flowability Behaviour of Self-Flow Refractory Castables

2010 ◽  
Vol 636-637 ◽  
pp. 124-129 ◽  
Author(s):  
D.G. Pinto ◽  
Abílio P. Silva ◽  
A.M. Segadaes ◽  
T.C. Devezas
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Raw Materials ◽  
High Hardness ◽  
Size Composition ◽  
High Melting Point ◽  
Refractory Castables ◽  
Materials Used ◽  
The Relationship

Alumina, with high melting point (2050°C), high hardness and mechanical strength, and excellent abrasion resistance, is one of the most common raw materials used in self-flow refractory castables (SFRC) for monolithic linings and is commercially available in various fine to coarse size classes. However, the performance of the refractory lining depends not only on the properties of its ingredients but also on its easy installation (good flowability). The aim of this work was to evaluate the relationship between the flowability index (FI) of fresh castable and the specific surface area (SSA) of its particles, which is mostly determined by the finer particles content. The results obtained showed that, by controlling the proportion between matrix and aggregate, it is possible to control the SSA of the refractory castable and find a mathematical relationship between the specific surface area and the minimum flowability index required to obtain a self-flow refractory castable. It is, thus, possible to optimize the refractory castable size composition and obtain an estimate for FI as a function of SSA. Using a minimum 45 wt.% matrix content in the castable mixture, a SSA value above 2.215 m2/g is obtained, which leads to FI ≥ 80%, the recommended value for self-flow.

Study on the Preparation and Particle Size Control of Silica Sphere in a Sol-Gel Process

2013 ◽  
Vol 787 ◽  
pp. 52-57
Author(s):  
Ying Qiu ◽  
Shu Chun Hu ◽  
Jing Zhai ◽  
Zhi Jian Lin ◽  
Wen Feng Liu ◽  
...  
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Sol Gel ◽  
Size Control ◽  
Ammonia Concentration ◽  
Amorphous Structure ◽  
Silica Sphere ◽  
Sol Gel Process ◽  
Key Factor ◽  
Average Size

Silica sphere has wide applications not only in the field of physical chemistry dealing with dynamic behavior and stability of particulate systems, but also in industries including catalysts, ceramics, pigments, pharmacy, etc. However, the control on the particle size is a key factor in the preparation process of silica sphere. In this paper, silica sphere with uniform sphere morphology and amorphous structure was prepared by a sol-gel method, and the control of particle size was emphatically studied. The results showed that the particle size of the as-prepared silica sphere was obviously influenced by the raw materials concentration. The average size of the product increased from 0.66 μm to 0.90 μm when ethanol concentration increased from 7.14M to 9.55M, increased from 0.50 μm to 0.90 μm with the increase of ammonia concentration in the range of 1.88M to 2.36M, and increased from 0.47 to 0.90 μm while tetraethoxysilane concentration increased from 0.08M to 0.11M. Further study indicated that the silica particle size was also influenced by reaction temperature, it increased with the increase of temperature from 26°C to 28°C, and decreased with the further increase of temperature in the scope of 28°C to 32°C.

Advances in Research on Influence of Raw Materials on Workability of Fresh Concrete: A Review

2009 ◽  
Vol 405-406 ◽  
pp. 83-88 ◽  
Author(s):  
Gai Fei Peng ◽  
Zhan Qi Guo ◽  
Piet Stroeven ◽  
Ri Gao ◽  
Jiu Feng Zhang
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Fresh Concrete ◽  
Raw Materials ◽  
Experimental Tests ◽  
Solid Particles ◽  
Future Research ◽  
Negative Effect ◽  
The Relationship ◽  
Positive Effect

A literature review was carried out to identify advances in research on workability of fresh concrete via both experimental tests and modeling, especially high performance concrete and self-compacting concrete. As to the relationship between fluidity of concrete and that of paste, future research can be conducted in two aspects, i.e. one is the influence of the quantity of paste in concrete, and another is the influence of fluidity of paste affected by a couple of factors. Most literature proved that the flow of concrete depends both on positive effect and negative effect, the former promote fluidity, such as dispersing, filling and lubricating, and the latter restricts fluidity, such as formation of particle coagulation, an increase of wettable surface of solid particles and mechanical interlock.

Manufacture, Structure and Properties of Copper Foams

2013 ◽  
Vol 652-654 ◽  
pp. 1163-1166 ◽  
Author(s):  
Yun Zhou ◽  
Zeng Chuan Hong ◽  
Xiang Ping Ai ◽  
Xiao Qing Zuo
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
Volume Fraction ◽  
Raw Materials ◽  
Copper Particle ◽  
Structure And Properties ◽  
Copper Foam ◽  
Powder Sintering ◽  
Materials Used ◽  
Compacting Pressure

The raw materials used for manufacturing copper foams are the metal and a carbonate in powder form. Copper foams are fabricated by mixing metal and carbonate powder, sintering, and removing carbonate processing. The effect of Cu particle size, compacting pressure on the porosity of porous samples are analyzed. With SEM and EDS, particles binding and microstructure evolution during sintering are studied, and the mechanical properties of porous samples are measured. Results show that copper foams with the porosity of 60 % ~85 % are successfully prepared, pore size 50~1000㎛.The porosity of copper foams decreases with the pressure increasing and copper particle size decreasing at same volume fraction of copper powder . The compressive strength of copper foams decreases with the porosity raising, for the copper foam of 80% porosity, the compressive strength up to 20-30Mpa.The electrical conductivity of copper foams decreases with porosity increasing. Thermal expansion coefficient α of copper foams increases from 17 to 19*10-6 .K-1 when temperature rising from 50°C to 100°C.

scholarly journals Globalization’s Impact on the Usages of Imported and Local Building Materials in Jordan

2019 ◽  
Vol 8 (10) ◽  
pp. 971-975
Keyword(s):  
Design Process ◽  
Building Materials ◽  
Raw Materials ◽  
Study Data ◽  
Noticeable Increase ◽  
Materials Used ◽  
The Impact ◽  
The Relationship ◽  
Local Materials

The process of choosing building materials is an essential part of the design process. Whenever architects and interior designers start to think about a project, one of the first things they consider is the materials that will be used in the production of the project. There is little research exploring the impact of globalization on the level of using imported and local building materials in Jordan. Therefore, it is necessary to examine the impact of globalization on the level of using imported and local building materials in Jordan and explore the impact of using imported building materials on the level of using local building materials in Jordan. For the purpose of this study, data gathered about the usage of imported building materials in Jordan and analyzed to observe any drops of rises of using specific building materials. Also, this data was used to understand the most common imported building materials used. This study requires a total understanding of the relationship between globalization and building materials and their impact on the economy and the usage of imported and local building materials. comprehension of this relationship will make it possible to find solutions to integrate the use of imported building materials and local materials. Globalization impact can be observed in other sectors in Jordan. The building materials market is being affected by the phenomenon of globalization. It was found that there is a noticeable increase in imported building materials or raw materials that are needed to manufacture building materials. If the attitude toward the usage of local building materials in Jordan keep decreases and relying on imported building materials in the construction section, there will be a recession in the local building materials in Jordan. Having this recession will have a greater impact on the building materials and local factories in the long term.

Effects of Particle Size Distribution on Compacted Density of Lithium Iron Phosphate 18650 Battery

2018 ◽  
Vol 15 (4) ◽  
Author(s):  
Lei Chen ◽  
Zhenyu Chen ◽  
Shuaishuai Liu ◽  
Biaofeng Gao ◽  
Junwei Wang
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
High Performance ◽  
Lithium Iron Phosphate ◽  
Iron Phosphate ◽  
Specific Discharge ◽  
Average Size ◽  
Discharge Capacities ◽  
Selection Of

The effects of particle size distribution on compacted density of as-prepared spherical lithium iron phosphate (LFP) LFP-1 and LFP-2 materials electrode for high-performance 18650 Li-ion batteries are investigated systemically, while the selection of two commercial materials LFP-3 and LFP-4 as a comparison. The morphology study and physical characterization results show that the LFP materials are composed of numerous particles with an average size of 300–500 nm, and have well-developed interconnected pore structure and a specific surface area of 13–15 m2/g. For CR2032 coin-type cell, the specific discharge capacities of the LFP-1 and LFP-2 are about 165 mAh/g at 0.2 C. For 18650 batteries, results indicate that the LFP-3 material has the highest compacted density of 2.52 g/cm3 at a concentrated particle size distribution such as D10 = 0.56 μm, D50 = 1.46 μm, and D90 = 6.53 μm. By mixing two different particle sizes of LFP-1 and LFP-2, the compaction density can be increased significantly from 1.90 g/cm3 to 2.25 g/cm3.

Angle-dependent effects in Dynamic Light Scattering measurements of polydisperse particles

2021 ◽  
Author(s):  
Lin Jin ◽  
Curtis W Jarand ◽  
Mark L Brader ◽  
Wayne F Reed
Keyword(s):  
Particle Size ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Laser Wavelength ◽  
Recent Emergence ◽  
Large Particles ◽  
Average Diffusion ◽  
Biological Polymers ◽  
Average Size ◽  
The Relationship

Abstract Dynamic light scattering (DLS) is widely used for analyzing biological polymers and colloids. Its application to nanoparticles in medicine is becoming increasingly important with the recent emergence of prominent lipid nanoparticle-(LNP)based products, such as the SARS-CoV-2 vaccines from Pfizer, Inc.-BioNTech (BNT162b2) and Moderna, Inc. (mRNA-1273). DLS plays an important role in the characterization and quality control of nanoparticle-based therapeutics and vaccines. However, most DLS instruments have a single detection angle ,and the amplitude of the scattering vector, q, varies among them according to the relationship q=(n/sin(/2) where 0 is the laser wavelength. Results for identical, polydisperse samples among instruments of varying q yield different hydrodynamic diameters, because, as particles become larger they scatter less light at higher angles, so that higher-q instruments will under-sample large particles in polydisperse populations, and report higher z-average diffusion coefficients, and hence smaller effective hydrodynamic diameters than lower-q instruments. As particle size reaches the Mie regime the scattering envelope manifests angular maxima and minima, and the monotonic decrease of average size versus q is lost. This work examines results for different q-value instruments, using mixtures of monodisperse latex sphere standards, for which experimental measurements agree well with computations, and also polydisperse solutions of LNP, for which results follow expected trends. Mie effects on broad unimodal populations are also considered. There is no way to predict results between two instruments with different q for samples of unknown particle size distributions.

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