Effect of temperature, time, and shear force on the morphology and size of dendrites in A356-Al2O3 composites

2021 ◽  
pp. 002199832110526
Author(s):  
Mohsen Ostad Shabani ◽  
Amir Baghani ◽  
Mohammad Reza Rahimipour ◽  
Mansour Razavi ◽  
Mohammad Zakeri ◽  
...  

Dendrite arm spacing (DAS) plays a vital role in determining mechanical properties of aluminum casting composites. In this study, the effects of three different methods of gravity sand casting, squeeze casting, and semi-solid compo-casting with different electromagnetic stirring currents and times on the microstructural morphology of A356-Al2O3 composites were investigated. In order to investigate effects of shear forces on the formation of the globular-like structure, samples with different stirring electric current and times were produced by compo-casting in semi-solid state and analyzed. Optical emission microscopy was used to study the microstructure and DAS of nanocomposites. Quantitative analysis of microstructure was performed by utilizing an image analysis system. In this study, the optimum temperature for composite fabrication for this type of composite was calculated to obtain the most appropriate morphology and size of the microstructure. Also, the appropriate time to keep this composite at this temperature was obtained, and finally the relevant microstructures were fully discussed.

1998 ◽  
Vol 64 (10) ◽  
pp. 3807-3812 ◽  
Author(s):  
T. A. Reponen ◽  
S. V. Gazenko ◽  
S. A. Grinshpun ◽  
K. Willeke ◽  
E. C. Cole

ABSTRACT Airborne actinomycete spores, important contaminants in occupational and residential environments, were studied with respect to their (i) release into the air, (ii) aerodynamic and physical size while airborne, and (iii) survival after collection onto agar with an impactor. Three actinomycete species were selected for the tests to exemplify the three main spore types: Streptomyces albusfor arthrospores, Micromonospora halophytica for aleuriospores, and Thermoactinomyces vulgaris for endospores. The results show that the incubation conditions (temperature, time, and nutrients) needed for the development of spores for their release into air are different from the conditions that are needed for colony growth only. Additional drying of M. halophytica and T. vulgaris cultures was needed before spores could be released from the culture. The aerodynamic sizes of the spores, measured with an aerodynamic particle sizer, ranged from 0.57 (T. vulgaris) to 1.28 μm (M. halophytica). The physical sizes of the spores, when measured with a microscope and an image analysis system, were found to be smaller than previously reported in the literature. The relative recovery of the spores on agar media ranged from 0.5 (T. vulgaris) to 35% (S. albus). The results indicate that the culturability of the collected airborne actinomycete spores varies widely and is affected by several variables, such as the species and the sampling flow rate. Therefore, alternatives to commonly used cultivation methods need to be developed for the enumeration of actinomycete spores.


Author(s):  
A. V. Crewe ◽  
M. Ohtsuki

We have assembled an image processing system for use with our high resolution STEM for the particular purpose of working with low dose images of biological specimens. The system is quite flexible, however, and can be used for a wide variety of images.The original images are stored on magnetic tape at the microscope using the digitized signals from the detectors. For low dose imaging, these are “first scan” exposures using an automatic montage system. One Nova minicomputer and one tape drive are dedicated to this task.The principal component of the image analysis system is a Lexidata 3400 frame store memory. This memory is arranged in a 640 x 512 x 16 bit configuration. Images are displayed simultaneously on two high resolution monitors, one color and one black and white. Interaction with the memory is obtained using a Nova 4 (32K) computer and a trackball and switch unit provided by Lexidata.The language used is BASIC and uses a variety of assembly language Calls, some provided by Lexidata, but the majority written by students (D. Kopf and N. Townes).


Author(s):  
D.S. DeMiglio

Much progress has been made in recent years towards the development of closed-loop foundry sand reclamation systems. However, virtually all work to date has determined the effectiveness of these systems to remove surface clay and metal oxide scales by a qualitative inspection of a representative sampling of sand particles. In this investigation, particles from a series of foundry sands were sized and chemically classified by a Lemont image analysis system (which was interfaced with an SEM and an X-ray energy dispersive spectrometer) in order to statistically document the effectiveness of a reclamation system developed by The Pangborn Company - a subsidiary of SOHIO.The following samples were submitted: unreclaimed sand; calcined sand; calcined & mechanically scrubbed sand and unused sand. Prior to analysis, each sample was sprinkled onto a carbon mount and coated with an evaporated film of carbon. A backscattered electron photomicrograph of a field of scale-covered particles is shown in Figure 1. Due to a large atomic number difference between sand particles and the carbon mount, the backscattered electron signal was used for image analysis since it had a uniform contrast over the shape of each particle.


2018 ◽  
Author(s):  
F.B. Musaev ◽  
N.S. Priyatkin ◽  
M.V. Arkhipov ◽  
P.A. Shchukina ◽  
A.F. Bukharov ◽  
...  

Приведено описание разработанной авторами методики цифровой компьютерной морфометрии семян овощных культур на основе системы анализа изображений, состоящей из планшетного сканера и программного обеспечения для автоматических измерений. В основу метода положено представление о разнокачественности семян, обусловленной генетической неоднородностью самих семенных растений, используемых в промышленном семеноводстве. Физические свойства семян (их форма и линейные размеры) – основные параметры при определении их качества. Цифровые изображения семян получены при помощи планшетного сканера HP Sсanjet 200 на базе Агрофизического НИИ с использованием серийного программного обеспечения «Argus-BIO», производства ООО «АргусСофт» (г. Санкт-Петербург). Метод состоит из подбора контрастной подложки (фона) для сканирования семян с минимальными теневыми эффектами, калибровку программного обеспечения для привязки к истинным размерным величинам, подбор параметров измерений и автоматическое распознавание цифровых сканированных изображений семян. Представлены экспериментальные данные по морфометрии экологически разнокачественных семян фасоли овощной, матрикально разнокачественных семян укропа, пастернака и лука Кристофа. Семена укропа и пастернака, собранные из разных порядков ветвления семенного растения, значительно различались по величине линейных параметров. Наиболее показательный линейный параметр семян – площадь проекции. Предложенная авторами методика цифровой морфометрии, уже использована на практике и в перспективе может быть задействована в исследованиях экологической и матрикальной разнокачественности семян овощных культур. Так, она прошла апробацию на разнокачественных семенах пяти сортов фасоли овощной (Настена, Магура, Миробела, Морена, Бажена) полученных в пяти контрастных эколого-географических условиях среды (Москва, Белгород, Ставрополь, Омск, Горки) в 2011–2012 годах. В дальнейшем методика может быть использована для улучшения качества цифровых изображений семян, изучения разнокачественности семян в том числе и для совершенствования контроля за селекционным процессом. Кроме того, она применима для изучения взаимосвязи совокупности морфометрических характеристик семян и их посевных качеств.The description of the method of digital computer morphometry of vegetable seeds developed by the authors on the basis of the image analysis system consisting of a flatbed scanner and software for automatic measurements is given. The method is based on the idea of seed quality, due to the genetic heterogeneity of the seed plants used in industrial seed production. Physical properties of seeds (their shape and linear dimensions) are the main parameters in determining their quality. Digital image of the seed obtained using the flatbed scanner, HP Sсanjet 200 on the basis of the Agrophysical research Institute with serial software “Argus-BIO”, produced by LLC “Argussoft” (Saint-Petersburg). The method consists of selection of a contrast substrate (background) for scanning seeds with minimal shadow effects, calibration of software for binding to true size values, selection of measurement parameters and automatic recognition of digital scanned images of seeds. Experimental data on the morphometry of ecologically different-quality seeds of vegetable beans, matrix seeds of dill, Pasternak and Christoph onion are presented. Seeds of dill and parsnip, collected from different orders of branching of the seed plant, significantly differed in size of linear parameters. The most revealing linear parameter seed – area projection. The method of digital morphometry proposed by the authors has already been used in practice and in the future can be used in studies of ecological and matrix heterogeneity of vegetable seeds. So, it was tested on different quality seeds of five varieties of vegetable beans (Nastena, Magura, Mirobelа, Morena, Bazhenf) obtained in five contrasting environmental and geographical conditions (Moscow, Belgorod, Stavropol, Omsk, Gorki) in 2011-2012. In the future, the technique can be used to improve the quality of digital images of seeds, study of seed diversity, including to improve the control of the breeding process. In addition, it is applicable to study the relationship of the set of morphometric characteristics of seeds and their sowing qualities.


2020 ◽  
pp. 49-52
Author(s):  
Trine Aabo Andersen

A new fast measuring method for process optimization of sucrose crystallization using image analysis based on high quality images and algorithms is introduced. With the mobile, non-invasive at-line system all steps of the sucrose crystallization can be measured to determine the crystal size distribution. The image analysis system is easy to operate and is as well an efficient laboratory solution with user-friendly and customized software. In comparison to sieve analysis, image analyses performed with the ParticleTech Solution have been proven to be reliable.


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