Assessment of Homogeneity of Extruded Alumina-SiC Composite Rods Used in Microwave Heating Applications by Impedance Spectroscopy

2013 ◽  
Vol 1538 ◽  
pp. 323-328
Author(s):  
Justin R. Brandt ◽  
Rosario A. Gerhardt
Keyword(s):  
Electrical Conductivity ◽  
Electrical Response ◽  
Percolation Model ◽  
Homogeneous Distribution ◽  
Impedance Response ◽  
Silicon Carbide Whiskers ◽  
Percolation Behavior ◽  
Sic Whiskers ◽  
The Individual

ABSTRACTComposite rods consisting of Alumina (Al2O3) and Silicon Carbide whiskers (SiCw) are used to fabricate microwave cooking racks because they effectively act as a microwave intensification system that allows cooking at much faster rates than conventional microwave ovens. The percolation behavior, electrical conductivity and dielectric properties of these materials have been reported previously. However, it has been observed that the electrical response of the extruded bars is a function of the rod length and that long rods show substantially different behavior than thinner disks cut from them. A percolation model has been proposed that describes the effect of the alignment of the semiconducting SiC whiskers and the quality of the interfaces present in the composite rods: SiC-SiC and SiC-Al2O3-SiC for example. This study was undertaken with the goal of testing out whether the response of the individual sections could be used to generate the response of the full length rods and to assess the importance of the homogeneous distribution of the SiC fillers on the resultant impedance response.

scholarly journals Evaluation of the seedvigor of Tournefortia paniculata Cham. post-digestive tract of the ruby-crowned tanager Tachyphonus coronatus (Vieillot, 1822)

2019 ◽  
Vol 41 ◽  
pp. 15
Author(s):  
Sérgio Thode Filho ◽  
Heider Alves Franco ◽  
Emanuele Nunes de Lima Figueiredo Jorge ◽  
Mariana De Souza Oliveira ◽  
Jhon Lenon Genovez de Oliveira ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Digestive Tract ◽  
Digestive System ◽  
Forest Species ◽  
Ecological Process ◽  
Germination Test ◽  
Individual Level ◽  
Physiological Quality ◽  
The Individual

Endozoochory (dispersion with passage through the digestive system of animals) is one of the most important processes. It is included in the ecological process known as dispersive mutualism, benefit the species involved. The most used method to evaluate the physiological quality of seeds is carried out based on the traditional germination test. However, electrical conductivity tests with seeds of forest species are still scarce, especially those developed with the individual method, which provide greater fidelity to the results so that through this one can define the test by the mass methods. The current work aimed to investigate the vigor, from the electrical conductivity of the seeds of Tournefortia paniculata Cham. after passage through the digestive tract of a ruby-crowned tanager Tachyphonus coronatus (Vieillot, 1822). An expedition was conducted in a fragmented area of Atlantic Forest in process of reforestation in the campus of the IFRJ. After the capture of the passerine with mist nets, proceeded the identification of seeds shed in its feces. The experimental design was completely randomized with one treatments with five replicates. The results allowed concluded that the seed of the T. paniculata Cham. after digestive tract of the ruby-crowned tanager presented high electrical conductivity in three of its replicates at the individual level. 

Effect of SiC Whiskers on the Microstructure and Thermal Conductivity of Carbon Foam

2018 ◽  
Vol 917 ◽  
pp. 106-111 ◽  
Author(s):  
Sheng Jie Yu ◽  
Zhao Feng Chen ◽  
Yang Wang
Keyword(s):  
Thermal Conductivity ◽  
Random Distribution ◽  
Chemical Vapor ◽  
Carbon Foam ◽  
Laser Flash ◽  
Homogeneous Distribution ◽  
Silicon Carbide Whiskers ◽  
Sic Whiskers ◽  
Flash Diffusivity ◽  
Insulation Performance

This paper describes the modification of ultralight flexible carbon foam by chemical vapor deposition (CVD) of silicon carbide whiskers (SiCw). The effect of SiC whiskers on the microstructure and the thermal conductivity of carbon foam were investigated by scanning electron microscopy (SEM) and laser flash diffusivity method in a Netzsch LFA427. The results show that the macro-pores (~30 μm) of the carbon foam were divided by the random distribution of SiC whiskers. The diameter of SiC whiskers decreased with decreasing catalyst concentration which resulted in the improved microstructure with a smaller pore diameter (4~6 μm) and a more homogeneous distribution of the pores. The carbon foam reinforced by SiCw exhibits better insulation performance than the pristine carbon foam when the temperature exceeds 200°C.

scholarly journals Devising an express method for estimating the quality of colostrum and its components based on electrical conductivity

2021 ◽  
Vol 1 (11 (109)) ◽  
pp. 69-77 ◽  
Author(s):  
Valentyn Kozheshkurt ◽  
Ievgen Ivanov ◽  
Yevhenii Antonenko ◽  
Victor Katrich ◽  
Anatoly Bozhkov ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Molecular Mass ◽  
Raw Materials ◽  
Individual Characteristics ◽  
Biologically Active ◽  
Express Method ◽  
Fat Removal ◽  
Quality Of Products ◽  
The Individual

This paper reports the development of an express method for assessing the quality of biologically active substances derived from colostrum. We tested the hypothesis that there may be a dependence between the amount of protein that is part of the colostrum and its characteristic (a difference in molecular masses) and electrical conductivity. It has been shown that the colostrum contains several hundred proteins: it depends on the individual characteristics of cattle. The removal of lipids was accompanied by an increase in electrical conductivity from 5 % to 18 % compared to the whole colostrum while the subsequent removal of high-molecular proteins increased the electrical conductivity by 50‒100 % compared to skimmed colostrum: this depends on the individual characteristics of cattle. Such an individual feature of the colostrum composition reflects the uniqueness of the individual animal's metabolism. A mathematical model has been built for the dependence of the content of charged molecules in the solution of proteins on the molecular mass of proteins, which explains the relationship between electrical conductivity and the molecular mass of proteins. It was shown that there is a direct correlation between the colostrum electroconductivity and the temperature in a measuring cell in the range of temperatures from 14 °C to 19 °C. The electrical conductivity of colostrum components increased by no more than 20 % during storage (at a temperature of 3‒4 °C) up to 18 days, which is associated with protein degradation The electrical conduction method could be used to assess the colostrum composition during storage. Technology for obtaining different colostrum components (skimmed fraction and a fraction of low-molecular components) has been devised, as well as a method for assessing the quality of products based on the characteristics of electrical conductivity. Electrical conductivity is a promising method for assessing the quality of products that are derived from colostrum, at different shelf life at different stages of production: raw materials, fat removal, obtaining a fraction with a predefined composition of proteins

scholarly journals Massal and Individual Electrical Conductivity Tests and its Relationships with the Physiological Quality of Sweet Sorghum Seeds

2020 ◽  
Vol 8 (2) ◽  
pp. 407
Author(s):  
Joner Silveira Dalcin ◽  
Caren Alessandra Müller ◽  
Ubirajara Russi Nunes ◽  
Rodrigo Roso ◽  
Alberto Cargnelutti Filho ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Cold Test ◽  
Dry Mass ◽  
Shoot Length ◽  
Tukey Test ◽  
Physiological Quality ◽  
Rapid Tests ◽  
The Individual ◽  
The Relationship

Rapid tests such as electrical conductivity provide fast and consistent results regarding stratification of seed lots by vigor. They are important tools used to evaluate the physiological quality of seeds of several species, however, no such information was found for Sorghum bicolor. The objective of this study was to evaluate the relationship between the physiological quality of the seeds by the mass and individual conductivity tests. Four plots of the Fepagro 19 cultivar were analyzed through the degree of moisture, weight of one thousand seeds, first count and germination, radicular and shoot length, dry mass, cold test and emergence of field seedlings. Subsequently, they were submitted to mass electrical conductivity experiments with variations in the imbibition time (2, 4, 6, 8, 12 and 24 hours), temperature (20, 25 and 30 ºC), number of seeds (25 and 50), volume of water (50 and 75 mL) and individual (2, 4, 6, 8, 12 and 24 hours). The design was completely randomized and the data evaluated by the Tukey test. Only the lowest physiological quality batch was detected in the 20 °C, 75 mL and 25 seeds for 12 hours combinations; the individual test detected the least physiological quality batch, and it was possible to perform it in 24 hours.

scholarly journals Evaluation of the electrical conductivity of forest seeds after digestive tract of wild birds

2018 ◽  
Vol 40 ◽  
pp. 79
Author(s):  
Sérgio Thode Filho ◽  
Heider Alves Franco ◽  
Emanuele Nunes Nunes de Lima Figueiredo Jorge ◽  
Miqueias Da Silva Fernandes ◽  
Ildemar Ferreira ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Digestive Tract ◽  
Wild Birds ◽  
Individual Level ◽  
Genetic Potential ◽  
Physiological Quality ◽  
The Individual ◽  
Forest Seeds

The production of seedlings encompasses the need for knowledge of plant physiology, mainly related to seeds and their minutiae. The seed is the vehicle that carries the full genetic potential of a cultivar with superior characteristics. Vigor can be described as that seed property that determines its emergence under unfavorable conditions. According to the International Seed Testing Association (ISTA). The process of reforestation can happen through the production of seedlings and, through seed dispersal, this can occur due to the action of the plant itself (autochory), water (hydrochory), wind (anemochory), animals (zoochory), etc. The current work aimed to investigate the feasibility of using the individual electrical conductivity test to evaluate the physiological quality of seeds of forest species after passage through the digestive tract of wild birds. The results allowed inferring that the forest seeds after digestive tract of wild birds presented low electrical conductivity at the individual level. Thus, the seeds in study no presented loss force after digestive tract of wild birds.  Therefore, the birds only performed the role of individual dispersant.

scholarly journals Electrical conductivity test for evaluation of the pea seed vigor

2020 ◽  
Vol 1 (1) ◽  
pp. 89
Author(s):  
Edvan Costa da Silva ◽  
Wagner Menechini ◽  
Carolina Dos Santos Galvão ◽  
Luís Augusto Batista de Oliveira ◽  
Natália Cássia de Faria Ferreira ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Pisum Sativum ◽  
Low Cost ◽  
Seed Vigor ◽  
State University ◽  
Randomized Experimental Design ◽  
Physiological Quality ◽  
Pea Seeds ◽  
The Individual

The electrical conductivity test is routinely used to differentiate the physiological quality of seed lots, and has stood out for its ease of execution, low cost, speed, repeatability, and straightforward interpretation of results. This study aimed to establish a methodology for the electrical conductivity test in pea seeds (Pisum sativum L.) involving seed quantity and seed imbibition periods. The experiment was carried out at the Multidisciplinary Laboratory of the State University of Goiás, the campus of Ipameri Campus, in 2018. Pea seeds (Pisum sativum) stored in the seed laboratory of the same institution were used for this experiment. The completely randomized experimental design with four replications in a 4x6 factorial scheme was used. Four quantity of seeds (25, 50, 75, and 100 seeds) and six imbibition periods (4, 8, 12, 16, 20, and 24 h) at 25ºC were evaluated. The electrical conductivity test was performed with four replicates of 25, 50, 75, and 100 seeds each, weighed on a precision scale (0.001g) and placed in disposable plastic cups, with a capacity of 200 mL, containing 75 mL of distilled water. The cups were then kept in a BOD chamber, set at 25°C, and the measuring was performed after 4, 8, 12, 16, 20, and 24 h of imbibition with a conductivity meter and results were expressed in μS cm-1 g-1. There were no significant results for the interaction between the number of seeds and the imbibition time. Significant results were observed only for the individual effects of each factor. It is recommended to use 100 seeds of Maria pea, and 24 h for the electrical conductivity test.

Semi-automated methods for 3-D reconstruction of macromolecular complexes

1995 ◽  
Vol 53 ◽  
pp. 42-43
Author(s):  
B. Carragher ◽  
M. Whittaker
Keyword(s):  
Three Dimensional ◽  
Time Saving ◽  
Macromolecular Complexes ◽  
Symmetry Properties ◽  
Dimensional Reconstruction ◽  
Experienced Operator ◽  
Projection Images ◽  
The Individual ◽  
Natural Symmetry

Techniques for three-dimensional reconstruction of macromolecular complexes from electron micrographs have been successfully used for many years. These include methods which take advantage of the natural symmetry properties of the structure (for example helical or icosahedral) as well as those that use single axis or other tilting geometries to reconstruct from a set of projection images. These techniques have traditionally relied on a very experienced operator to manually perform the often numerous and time consuming steps required to obtain the final reconstruction. While the guidance and oversight of an experienced and critical operator will always be an essential component of these techniques, recent advances in computer technology, microprocessor controlled microscopes and the availability of high quality CCD cameras have provided the means to automate many of the individual steps.During the acquisition of data automation provides benefits not only in terms of convenience and time saving but also in circumstances where manual procedures limit the quality of the final reconstruction.

Use of fractals to describe microstructures of porous thick-film platinum electrodes

1992 ◽  
Vol 50 (1) ◽  
pp. 314-315
Author(s):  
Steven D. Toteda
Keyword(s):  
Fractal Dimension ◽  
Power Plants ◽  
Electrical Response ◽  
Cubic Phase ◽  
Platinum Electrodes ◽  
Fine Grained ◽  
Impedance Response ◽  
Platinum Particles ◽  
Energy Surfaces ◽  
Highly Porous

Zirconia oxygen sensors, in such applications as power plants and automobiles, generally utilize platinum electrodes for the catalytic reaction of dissociating O2 at the surface. The microstructure of the platinum electrode defines the resulting electrical response. The electrode must be porous enough to allow the oxygen to reach the zirconia surface while still remaining electrically continuous. At low sintering temperatures, the platinum is highly porous and fine grained. The platinum particles sinter together as the firing temperatures are increased. As the sintering temperatures are raised even further, the surface of the platinum begins to facet with lower energy surfaces. These microstructural changes can be seen in Figures 1 and 2, but the goal of the work is to characterize the microstructure by its fractal dimension and then relate the fractal dimension to the electrical response. The sensors were fabricated from zirconia powder stabilized in the cubic phase with 8 mol% percent yttria. Each substrate was sintered for 14 hours at 1200°C. The resulting zirconia pellets, 13mm in diameter and 2mm in thickness, were roughly 97 to 98 percent of theoretical density. The Engelhard #6082 platinum paste was applied to the zirconia disks after they were mechanically polished ( diamond). The electrodes were then sintered at temperatures ranging from 600°C to 1000°C. Each sensor was tested to determine the impedance response from 1Hz to 5,000Hz. These frequencies correspond to the electrode at the test temperature of 600°C.

Manageable Self in the Early Hellenistic Era

2010 ◽  
Vol 39 (2) ◽  
pp. 34-36
Author(s):  
Vaia Touna
Keyword(s):  
Social Economic ◽  
Ancient Greece ◽  
The Self ◽  
Hellenistic Period ◽  
Political Conditions ◽  
The Individual

This paper argues that the rise of what is commonly termed "personal religion" during the Classic-Hellenistic period is not the result of an inner need or even quality of the self, as often argued by those who see in ancient Greece foreshadowing of Christianity, but rather was the result of social, economic, and political conditions that made it possible for Hellenistic Greeks to redefine the perception of the individual and its relationship to others.

Reflecting the Sky in Water

2017 ◽  
Vol 3 (1) ◽  
pp. 112-126 ◽  
Author(s):  
Ilaria Cristofaro
Keyword(s):  
The Unconscious ◽  
Related Case ◽  
Quality Of Water ◽  
Fluid Properties ◽  
Phenomenological Perspective ◽  
Auto Ethnography ◽  
The Individual ◽  
Artificial Water ◽  
Land Water

From a phenomenological perspective, the reflective quality of water has a visually dramatic impact, especially when combined with the light of celestial phenomena. However, the possible presence of water as a means for reflecting the sky is often undervalued when interpreting archaeoastronomical sites. From artificial water spaces, such as ditches, huacas and wells to natural ones such as rivers, lakes and puddles, water spaces add a layer of interacting reflections to landscapes. In the cosmological understanding of skyscapes and waterscapes, a cross-cultural metaphorical association between water spaces and the underworld is often revealed. In this research, water-skyscapes are explored through the practice of auto-ethnography and reflexive phenomenology. The mirroring of the sky in water opens up themes such as the continuity, delimitation and manipulation of sky phenomena on land: water spaces act as a continuation of the sky on earth; depending on water spaces’ spatial extension, selected celestial phenomena can be periodically reflected within architectures, so as to make the heavenly dimension easily accessible and a possible object of manipulation. Water-skyscapes appear as specular worlds, where water spaces are assumed to be doorways to the inner reality of the unconscious. The fluid properties of water have the visual effect of dissipating borders, of merging shapes, and, therefore, of dissolving identities; in the inner landscape, this process may represent symbolic death experiences and rituals of initiation, where the annihilation of the individual allows the creative process of a new life cycle. These contextually generalisable results aim to inspire new perspectives on sky-and-water related case studies and give value to the practice of reflexive phenomenology as crucial method of research.

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