scholarly journals Characterization of Slurry-Cast Layer Compounds for 3D Printing of High Strength Casting Cores

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6149
Author(s):  
Patricia Erhard ◽  
Jan Angenoorth ◽  
Joachim Vogt ◽  
Johannes Spiegel ◽  
Florian Ettemeyer ◽  
...  
Keyword(s):  
3D Printing ◽  
Bending Strength ◽  
State Of The Art ◽  
Temperature Stability ◽  
High Strength ◽  
Process Window ◽  
Drying Process ◽  
The Mean ◽  
Drying Conditions

Additive manufacturing of casting cores and molds is state of the art in industrial application today. However, improving the properties of chemically bonded casting cores regarding temperature stability, bending strength, and surface quality is still a major challenge. The process of slurry-based 3D printing allows the fabrication of dense structures and therefore sinterable casting cores. This paper presents a study of the slurry-based fabrication of ceramic layer compounds focusing on the drying process and the achievable properties in slurry-based 3D printing of casting cores. This study aims at contributing to a better understanding of the interrelations between the drying conditions in the 3D printing process and the properties of sintered specimens relating thereto. The drying intensity influenced by an IR heater as well as the drying periods are varied for layer thicknesses of 50, 75, and 100 µm. Within this study, a process window applicable for 3D printing of sinterable casting cores is identified and further indications are given for optimization potentials. At layer heights of 75 µm, bending strengths between ~8 and 11 MPa as well as densities of around 50% of the theoretical density were achieved. Since the mean roughness depth Rz is determined to be <30 µm in plane, an application of slurry-based 3D printing in investment casting is conceivable.

Clinical Characteristics in Neonates with Alloimmune Neutropenia: Significance of the Detection of Antineutrophil Antibodies

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4647-4647
Author(s):  
Yoko Mizoguchi ◽  
Kazuhiro Nakamura ◽  
Shuhei Karakawa ◽  
Takashi Sato ◽  
Rie Onodera ◽  
...  
Keyword(s):  
Japanese Population ◽  
Clinical Characteristics ◽  
Spontaneous Recovery ◽  
Clinical Course ◽  
Case Reports ◽  
High Strength ◽  
Long Duration ◽  
Control Serum ◽  
The Mean

Abstract Neonate alloimmune neutropenia (NAIN) is caused by the transplacental transfer of maternal alloantibodies directed against antigens on the infant’s neutrophils. To date, there are scant studies about its clinical characteristics and characterization of antineutrophil antibodies though some case reports are found. In this study we analyzed 11 cases with NAIN from January 2005 to December 2007. The diagnosis of NAIN was confirmed by the transient neutropenia less than 500/μl of absolute neutrophil count (ANC), the detection of maternal antineutrophil antibody, the incompatibility of neutrophil antigens between parents, and their mothers without autoimmune diseases. Antineutrophil antibodies were detected by granulocyte indirect immunofluorescence test using flow cytometry. To quantify the strength of the antibodies, the ratio of the mean fluorescence channel of each sample to that of control serum was expressed as relative fluorescence intensity according to the method reported previously (Blood99: 3468, 2002). The median age at diagnosis in NAIN patients was 8 days after birth ranged from 0 to 30 days. The average of ANC at the presentation was 170/μl ranged from 0 to 500/μl. All antineutrophil antibodies detected in sera of both neonates and their mothers were against HNA-1 antigens. The alloantibody against HNA-1a was found in 2 cases, that against HNA-1b was in 6 cases, and that against FcγR IIIb was found in 3 cases. The fact that the frequencies of homozygote of HNA-1a and HNA-1b in Japanese population were approximately 50% and 12%, respectively may reflect the frequency of alloantibody specificity in NAIN. During the neutropenic period, 7 cases with NAIN showed mild to moderate infections associated with neutropenia, such as pyrexia and pyodermia. In contrast, 4 of 11 cases with NAIN did not have any infectious episodes in their clinical course. In all patients, the spontaneous recovery of neutropenia with the disappearance of alloantibody was observed within 6 months (median 85 days ranged from 3 weeks to 6 months). The duration until spontaneous resolution of neutropenia was dependent on the strength of alloantibody found in sera of the mothers and neonates. Two patients with significantly high strength of alloantibodies had the relatively long duration to restore the neutropenia(4 months and 6 months). In conclusion, the specificity of antineutrophil antibodies in patients with alloimmune neutropenia is dependent on the frequencies of neutrophil antigens in Japanese population. The quantification of alloantibodies in neonates and their mothers may be useful in considering the clinical course of neutropenia in neonates.

In-Situ Characterization of Stress Development in Gelatin Film During Controlled Drying

1999 ◽  
Vol 594 ◽  
Author(s):  
Mengcheng Lu ◽  
Siu-Yue Tam ◽  
P. Randall Schunk ◽  
C. Jeffrey Brinker
Keyword(s):  
Plastic Deformation ◽  
Gelatin Film ◽  
Rate Variation ◽  
Drying Process ◽  
In Situ Characterization ◽  
Stress Development ◽  
Gelatin Films ◽  
Drying Conditions

AbstractDrying of gelatin films was studied by an in-situ cantilever beam method combined with spectroscopic ellipsometry, enabling measurement of the stress development, film shrinkage and compositional change during the drying process. Experiments are carried out under different drying conditions (such as drying extent variation, drying rate variation). The film experiences stress relaxation that indicates visco-elastic relaxation or plastic deformation happened during drying process. Plastic deformation is verified by carefully reversing the drying process, however, the plastic deformation accompanied by visco-elastic relaxation complicates the case of finding the value of the yield stress.

scholarly journals Evaluation of Kalalani vermiculite for production of high strength porcelain insulators

2019 ◽  
Vol 51 (2) ◽  
pp. 223-232 ◽  
Author(s):  
Blasius Ngayakamo ◽  
Eugene Park
Keyword(s):  
Water Absorption ◽  
Bulk Density ◽  
Bending Strength ◽  
Raw Materials ◽  
High Strength ◽  
Microstructural Characterization ◽  
Dielectric Strength ◽  
Raw Material ◽  
Porcelain Insulators

The present work has evaluated Kalalani vermiculite as a potential raw material for the production of high strength porcelain insulators. Three porcelain compositions were prepared to contain 0, 20 and 30 wt% of Kalalani vermiculite. Porcelain samples were fabricated using a semi-drying method. The chemical, mineralogical phases and microstructural characterization of the raw materials were carried out using XRF, XRD, and SEM techniques, respectively. Water absorption, bulk density, dielectric and bending strengths were performed on porcelain samples fired up to 1300?C. However, at the sintering temperature of 1250?C, the porcelain sample with 20 wt% of Kalalani vermiculite gave the dielectric strength of 61.3 kV/mm, bending strength of 30.54 MPa, bulk density of 2.21 g/cm3 and low water absorption value of 0.21 % which is the prerequisite properties for high strength porcelain insulators. It was therefore concluded that Kalalani vermiculite has the potential to be used for the production of high strength porcelain insulators

scholarly journals Study of Four Onion Varieties Drying Kinetics in an Oven and a Solar Greenhouse

2019 ◽  
Vol 8 (3) ◽  
pp. 59
Author(s):  
Ngoné Fall Beye ◽  
Nicolas Cyrille Ayessou ◽  
Cheikhou Kane ◽  
Mariame Niang Mbaye ◽  
Cheikh Talla ◽  
...  
Keyword(s):  
Lower Cost ◽  
Physicochemical Characterization ◽  
Drying Kinetics ◽  
Solar Drying ◽  
Drying Process ◽  
Allium Cepa L ◽  
Solar Greenhouse ◽  
Drying Conditions

Onion production (Allium cepa L.) in Senegal reached 390 000 tons in 2016. Due to post-harvest losses, annual demand (150 000 and 250 000 tons) is being met through imports. This work consists in proposing a drying process at a lower cost to overcome this dependence and preserve the quality of the product. The optimization of local onion varieties drying in an oven and in solar greenhouse, as well as the physicochemical characterization of the products were carried out. The moisture of fresh onion bulb varies between 85.56 &plusmn; 0.60 and 89.13 &plusmn; 0.69 (%). To obtain a moisture &pound; 8.89 &plusmn; 0.16 (%) ensuring stability, the optimal drying conditions in the oven are 60&deg; C / 6H (Galmi Violet) and 7H (Safari, Gandiol F1 and Orient F1). Under these conditions, the content of polyphenols in g equivalent of gallic acid / 100 g db increases (0.111 &plusmn; 0.0040 to 0.312 &plusmn; 0.0041 before drying, 0.546 g &plusmn; 0.0117 to 0.837 &plusmn; 0.0091 after drying). Optimum solar drying in a greenhouse is obtained between temperatures of 35 to 65&deg; C / 8H-9H. From a perspective of sustainable development, the perspective is the modeling of drying kinetics in a solar greenhouse.

scholarly journals DRYING OF RYE (LOLIUM MULTIFLORUM L.) IN FIXED BED WITH PARALLEL AIR FLOW

Engevista ◽  
2016 ◽  
Vol 18 (1) ◽  
pp. 11
Author(s):  
Akel Ferreira Kanaan ◽  
Janice Botelho Souza Hamm ◽  
Camila Gomes Flores ◽  
João Carlos Pinto Oliveira ◽  
André Ricardo Felkl de Almeida
Keyword(s):  
Lolium Multiflorum ◽  
Air Flow ◽  
Fixed Bed ◽  
Drying Process ◽  
Air Velocity ◽  
Physiological Characterization ◽  
Physiological Quality ◽  
Drying Conditions

This work aimed to study the drying of ryegrass seeds (Lolium multiflorum L.) in fixed bed dryer with parallel air flow. The study consisted of physical and physiological characterization of seeds, seed rewetting, study the desorption isotherms of rewetted seeds and the drying process  of the rewetted seeds under the following conditions: temperature from 40 to 60 ° C, air velocity 1.0 and 2.0 m/s and the height of the tray 0.005 and 0.01 m. The experimental data showed that the drying conditions applied to the seeds can significantly influence the moisture content and the physiological quality of the final product.

scholarly journals Variations in Physico-Mechanical Properties of Lonchocarpus sericeus (Poir), a Lesser-Used Species in West Africa

2021 ◽  
Vol 71 (3) ◽  
pp. 252-261
Author(s):  
Lawrence Olanipekun Aguda ◽  
Babatola Olufemi ◽  
Babatunde Ajayi ◽  
Olajide Rasaq Adejoba ◽  
Adedeji Robert Ojo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Modulus Of Elasticity ◽  
Bending Strength ◽  
High Strength ◽  
Modulus Of Rupture ◽  
Wood Age ◽  
Lonchocarpus Sericeus ◽  
The Mean ◽  
End Use

Abstract This study investigates the properties of Lonchocarpus sericeus to determine its potential use for timber. Three matured trees of L. sericeus were selected from a forest located in Longe Village, Oluyole Local Government Area in Oyo State, Nigeria. Discs from the harvested trees were collected at the base (10%), middle (50%), and top (90%) and further partitioned into inner wood, center wood, and outer wood. An investigation was carried out to characterize the wood age, density, shrinkage, impact strength, modulus of elasticity, modulus of rupture, compressive, and shear strength. The ages were 28, 29 and 32 years. The mean wood density at 12 percent moisture content was 836.63 kg/m3, which shows that it belongs to the high-density wood category. The mean shrinkage values in the radial, tangential, and longitudinal directions were 2.50, 3.99, and 0.78 percent respectively; the volumetric shrinkage was 6.36 percent. These shrinkage values were indicative of good dimensional stability. The mean impact bending strength, modulus of rupture, modulus of elasticity, maximum shear strength parallel to grain, and maximum compression strength parallel to the grain were 24.14, 114.18, 11,276, 12.76, and 47.16 N/mm2, respectively. End-use assessments suggest that the wood species can be used in similar applications as well-known timbers. The study found L. sericeus to be very dense with high strength in comparison to well-known timbers. It was observed that the mechanical properties of the species decrease from the base to the top and also increase from the outer wood to the core wood.

Ceramic Materials. Effects of Fracture Origin and Microstructure on Bending Strength of High-Strength Si3N4.

1994 ◽  
Vol 43 (489) ◽  
pp. 599-605 ◽  
Author(s):  
Akira YAMAKAWA ◽  
Takehisa YAMAMOTO ◽  
Tomoyuki AWAZU ◽  
Kenji MATSUNUMA ◽  
Takao NISHIOKA
Keyword(s):  
Bending Strength ◽  
High Strength ◽  
Ceramic Materials ◽  
Fracture Origin

UNS R54620

Alloy Digest ◽  
1987 ◽  
Vol 36 (7) ◽  
Keyword(s):  
Titanium Alloy ◽  
High Temperature ◽  
Time Use ◽  
Temperature Stability ◽  
High Strength ◽  
Heat Treating ◽  
High Temperature Stability ◽  
Beta Titanium Alloy ◽  
Beta Titanium ◽  
Long Time

Abstract UNS No. R54620 is an alpha-beta titanium alloy. It has an excellent combination of tensile strength, creep strength, toughness and high-temperature stability that makes it suitable for service to 1050 F. It is recommended for use where high strength is required. It has outstanding advantages for long-time use at temperatures to 800 F. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and bend strength as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ti-86. Producer or source: Titanium alloy mills.

Caracterização da Peneira Média em Clones de Coffea canephora

REVISTA FIMCA ◽  
2018 ◽  
Vol 5 (2) ◽  
pp. 28-31
Author(s):  
Darlan Darlan Sanches Barbosa Alves ◽  
Victor Mouzinho Spinelli ◽  
Marcos Santana Moraes ◽  
Carolina Augusto De Souza ◽  
Rodrigo da Silva Ribeiro ◽  
...  
Keyword(s):  
Genetic Improvement ◽  
Block Design ◽  
Coffea Canephora ◽  
Coffee Production ◽  
Randomized Block Design ◽  
Significant Difference ◽  
The Mean ◽  
Four Blocks ◽  
Selection Of

Introdução: O estado de Rondônia se destaca como tradicional produtor de café, sendo o segundo maior produtor brasileiro de C. canephora. No melhoramento genético de C. canephora, a seleção de plantas de elevada peneira média está associada à bebida de qualidade superior. Objetivos: O objetivo desse estudo foi avaliar a variabilidade genética de clones de C. canephora para o tamanho dos grãos, mensurado a partir da avaliação da peneira média (PM). Materiais e Métodos: Para isso, foi conduzido ao longo de dois anos agrícolas experimento no campo experimental da Embrapa no município de Ouro Preto do Oeste-RO, para a avaliação da peneira média de 130 genótipos (clones) com características das variedades botânicas Conilon, Robusta e híbridos intervarietais. O delineamento experimental utilizado foi de blocos ao acaso, com quatro repetições de quatro plantas por parcela. Resultados: Não houve resultados significativos para a interação clones X anos, indicando uma maior consistência no comportamento das plantas ao longo do tempo. Porém foram observadas diferenças significativas para o tamanho dos grãos entre os genótipos avaliados, possibilitando selecionar genótipos superiores. Conclusão: Os genótipos agruparam-se em cinco classes de acordo com o teste de média, subsidiando a caracterização de um gradiente de variabilidade da característica avaliada ABSTRACTIntroduction: Coffea canephora accounts for approximately 35% of the world's coffee production. The state of Rondônia stands out as a traditional coffee producer, being the second largest Brazilian producer of C. canephora. In the classical genetic improvement of C. anephora, the selection of plants of high average sieve is associated with a drink of superior quality. Objectives: The objective of this udy was to evaluate the genetic variability of Coffea canephora clones for the agronomic medium sieve (PM). Materials and Methods: The experiment was conducted in the experimental field of Embrapa, municipality of OuroPreto do Oeste-RO, located at coordinates 10º44'53 "S and 62º12'57". One hundred thirty genotypes (clones) of botanical characteristics Conilon, Robusta and intervarietal hybrids were evaluated in the agricultural years 2013-2014 and 2014-2015. The experimental design was a randomized block design with four blocks and four plants per plot, spacing 3.5 x 1.5 meters between plants. Results: Significant difference was found for the grain size. According to the F test, at 5% probability, the genotypes were grouped into five classes according to the mean test. Conclusion: The results obtained subsidized the characterization of a variability gradient of the evaluated trait.

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