Aggregate Degradation Testing by Gyratory Testing Machine

Author(s):  
Byron E. Ruth ◽  
Mang Tia

The Gyratory Testing Machine (GTM) equipped with an air roller was used to investigate the dry and wet degradation of six aggregates. Three gradings similar to those for the Los Angeles (LA) abrasion test were evaluated in the GTM by using 25, 50, 100, and 200 revolutions. The test data indicated substantial differences in gradation of the aggregates after testing. Type and initial size of the aggregate influenced the amount and characteristics of degradation. Regression analyses of the data resulted in the development of GTM degradation prediction equations using the LA abrasion loss. The most important goal for the GTM test results was to define gradation and the effect of moisture, instead of using only a relative indicator such as LA abrasion loss. Four aggregate blends were tested in the GTM to simulate degradation produced in handling and processing of aggregate through a drum mixer and drum dryer. These test results duplicated some of the gradations obtained after the material had passed through the drum.

2003 ◽  
Vol 1 (2) ◽  
pp. 198-207
Author(s):  
H. Mabel Preloran ◽  
Silvia Balzano

This paper explores the emotional world of a recent Mexican immigrant who lives in Los Angeles and is awaiting the results of the amniocentesis she has ambivalently agreed to. She is 45 years old and has given birth to two children with severe disabilities and two who are apparently normal. We focus our analysis on the woman's reactions and feelings during the nine days she spends waiting for the test results. We show that the standard prenatal genetic clinical protocol aimed at providing medical education and requiring professional neutrality and emotional detachment left the woman feeling rejected and subsequently unwilling to seek information or support from her clinicians. We find that while the intent of a protocol of neutrality is to enable patients to make informed decisions without feeling pressure from clinicians, some women want greater emotional engagement. We argue that professional neutrality can inhibit patient-clinician communication, hamper medical education, and ultimately detract from patients' ability to make informed medical choices. / El presente artículo explora el mundo emocional de Rocío, una inmigrante mexicana, quien se encuentra esperando los resultados de una amniocentesis que aceptó hacerse, a pesar de las dudas sobre la credibilidad y utilidad de la misma. Rocío, de 45 años, tenía ya otros hijos, dos con anormalidades severas y dos aparentemente sanos. Centramos nuestro análisis en los sentimientos y reacciones durante los nueve días que transcurren mientras espera el diagnóstico. En este trabajo mostramos cómo la forma de presentar la información médica puede llegar a entorpecer la toma de decisión de un paciente. El protocolo genético tiene por meta proveer información médica manteniendo una cierta distancia profesional y emocional. Estas condiciones hacen que, en nuestro estudio de caso, la paciente se sienta rechazada y sin deseos de acercarse al personal médico, ya sea en busca de apoyo emocional o información que aclararía sus dudas. Creemos que, mientras el objetivo de la neutralidad profesional es asegurar que el paciente decida con los conocimientos adecuados y, a la vez, sin sentirse presionado, algunas mujeres preferirían un mayor acercamiento emocional por parte del personal médico cuando deben decidir sobre pruebas o tratamientos. Creemos que la neutralidad profesional puede llegar a inhibir la comunicación médico-paciente, dificultar la comprensión de la información y, por último, obstaculizar la habilidad de tomar decisiones informadas por parte de los pacientes.


2017 ◽  
Author(s):  
Adelia Dwidarma Nataadmadja ◽  
Oki Setyandito ◽  
Eduardi Prahara ◽  
Ida Riyanti

2013 ◽  
Vol 12 (04) ◽  
pp. 1350021 ◽  
Author(s):  
S. KAHRAMAN ◽  
M. S. DELIBALTA ◽  
R. COMAKLI

Compared to the indirect tests, the determination of the Los Angeles abrasion loss is time consuming and expensive, and requires a large amount of samples. For this reason, the prediction of Los Angeles abrasion loss from some indirect tests is useful for preliminary studies. In this study, Los Angeles abrasion, noise level (NL) measurement, density, and porosity tests were carried out on 27 different rock types such as igneous, metamorphic, and sedimentary. The test results were evaluated using the simple and multiple regression analysis. A good relation was found between the Los Angeles abrasion loss and the NL. In order to check the possibility of obtaining more significant relations, multiple regression analysis was performed by including density and porosity values. However, the regression analysis showed that the correlation coefficients of the multiple regression equations were slightly higher than that of the simple regression equation. Since the simple regression equation is practical and statistically significant, it is suggested for estimation purpose. In conclusion, it can be said that Los Angeles abrasion loss of aggregates can be reliably estimated from NL measurement.


2021 ◽  
Vol 2 (1) ◽  
pp. 17-20
Author(s):  
Misbachuddin

 This study aimed to decide how to design a kart chassis and the strength of the welded joints. In this design, the chassis frame is made of tubular profile steel, which is designed to withstand most of the loads in a vehicle. The chassis was designed using a computer application, namely Auto CAD 2007. Assembly using carbon steel pipes connected using SMAW welding with E6013 RB 2.6 mm welding wire with a current of 75 A, 1G place. The test is carried out with a tensile testing machine. The material is pulled past the most stretch elasticity limit until finally, the specimen reaches the limit (breaks). The tensile test takes about 3-5 minutes with a load of 10-20N. The test results show the average tensile strength of the iron pipe is 0.512 Mpa.


Author(s):  
Ahmad Adlie Shamsuri ◽  
Khalina Abdan ◽  
Tatsuo Kaneko

In this prelude study, the gellan gum/kenaf core fiber (KCF) biocomposite films were fabricated with the addition of imidazolium-based ionic liquids such as 1-butyl-3-methylimidazolium chloride (Bmim Cl), 1,3-dimethylimidazolium methylsulphate (Dmim MeSO4), 1-ethyl-3-methylimidazolium acetate (Emim Ac), and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (Emim OTf). The fabrication of the biocomposite films was carried out by mixing KCF and the ionic liquids in an aqueous solution, followed by dissolution of gellan gum in the same solution at a temperature of 90°C. The mixed solution was gelled at room temperature, and the formed gel was dried in an oven at 40°C for 48 hours to obtain a freestanding biocomposite film. The fabricated films were characterized by using a universal testing machine to acquire tensile properties. The tensile test results indicated that the biocomposite film added with Emim Ac possesses a higher tensile extension at maximum (up to 24%) than the biocomposite film without ionic liquid (added with glycerol). In addition, the biocomposite film added with Emim OTf has a higher tensile modulus at maximum (up to 758%) compared to the biocomposite film without ionic liquid. In conclusion, the tensile properties of the gellan gum/KCF biocomposite films can be improved with the addition of Emim-based ionic liquids with different counter anions.


1971 ◽  
Vol 6 (4) ◽  
pp. 429-431
Author(s):  
William J. Woolbright

Part of the responsibility of a reading therapist is to report to the parents the results of specialized programs developed for their children. Whether the report is made in person or sent to the parents or teachers of the children, there can be confusion or misunderstanding when grade-level scores are used. Over a period of time, and after a review of numerous parent conferences and discussions with local school administrators and teachers, the following report was prepared by the Academic Achievement and Learning Group, Los Angeles, California, to better communicate with parents and school personnel who are concerned about students' work in remedial reading.


2019 ◽  
Vol 9 (23) ◽  
pp. 5265 ◽  
Author(s):  
González ◽  
Saldaña ◽  
Arzúa

Rock mechanics and rock engineering projects require determining, among other parameters, the uniaxial compressive strength (UCS) of rock. For such a purpose, it is not uncommon to perform ultrasonic pulse laboratory tests. Many researchers have found experimental relationships between strength and P-wave velocity, but these relationships are based mainly on dry conditions and without considering any other physical or chemical characteristics of the studied rock. Specifically, for limestone, there are 11 correlations reported in the literature, eight of which are simple and the remaining three are multiple, and, among the latter, only two of them consider the saturation. In order to evaluate the combined effect of P-wave velocity, density, and porosity on the UCS of saturated limestone, simple and multiple regression analyses were carried out on the test results of 13 saturated limestone specimens to determine the parameters of both previously mentioned predictive models. The results showed that density is not correlated with strength.


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