Rock masses of the primary copper ore at the El Teniente mine fail mainly through the infill of preexisting veins during the caving processes, especially through those composed of less than 35% hard ...minerals (quartz and pyrite). In this study, the Synthetic Rock Mass (SRM) approach is used to reproduce the results of ten uniaxial compression tests on veined core-size samples of El Teniente Mafic Complex (CMET) lithology, from El Teniente mine, Codelco-Chile. At the scale of the tested samples it is observed that veins composed mostly of quartz dominate the failure process. The developed methodology considers generating a deterministic Discrete Fracture Network (DFN) based on the veins mapped at the surface of each core sample. Then, the micro-parameters of the Bonded Particle Model (BPM) are calibrated to represent the macro-parameters of the average block of intact rock within all samples. Next, the micro-parameters of the Smooth-Joint Contact Model (SJCM), which represent the mechanical properties of veins, are calibrated to reproduce the stress–strain curves and the failure modes of the veined core-size samples measured during the laboratory tests. Results show that the SRM approach is able to reproduce the behavior of the veined rock samples under uniaxial loading conditions. The strength and stiffness of veins, as well as the vein network, have an important impact on the deformability and global strength of the synthetic samples. Contrary to what was observed in the laboratory tests, synthetic samples failed mainly through weak veins. This result is expected in the modeling given that anhydrite veins are considered weaker than quartz veins. Further research is required to completely understand the impact of veins on the behavior of rock masses.
•The Synthetic Rock Mass is used to simulate the behavior of veined core-size samples.•A deterministic discrete fracture network is built to represent the veins.•Samples fail preferentially though quartz vein under uniaxial compression tests.•The model is calibrated and verified with two and eight rock samples respectively.•Vein microparameters and network have a major impact on the behavior of the sample.
The present work demonstrates that FWHM profile broadening of the diffraction line reflected from a system of crystallographic planes is observed under short-term static loading of flat samples of ...09G2S structural steel within the limits of Hooke’s law by the X-ray diffraction method. It has been established that the experimentally revealed change in the FWHM profile broadening of the diffraction line can indicate the development of elastic deformations of the crystal lattice of structural steels. It will allow physical substantiating of defined values of the safety coefficient based on new theoretical concepts of localized vibrational modes that are discrete breathers caused by distortions of the crystal lattice
There are sufficiently long periods during the operation of steel structures, for which the structures do not experience the effects of external static and / or dynamic loads, except for their own ...gravity. A decrease in the level of the structure stress-strain state will promote relaxation processes in the substructure of the structural material. Сhanges in the substructure of 09G2S pipe steel were studied using laboratory samples. The samples were subjected to cyclic deformation in 2009 and then laid out for long-term storage. Multiple X-ray photographs of long time placed samples indicate a significant relaxation of stresses with a prolonged absence of a force field affecting the structural steel substructure. It was revealed that the experimentally determined values by the method of full width at half-maximum broadening of the diffraction lines profiles, measured in 2009 immediately after cyclic deformation of three groups of laboratory samples of low-alloy pipe steel at three different cycle stresses amplitude close to yielding, significantly decrease after holding for a long storage time in an unstressed state. It has been shown that the long-term storage of samples subjected to cyclic loading with the cycle stresses amplitude not exceeding the yield strength of structural pipe steel promotes the stress-strain state relaxation.
Purpose: Drones are an emerging technology with the potential to improve laboratory logistics. This study is based on the hypothesis that the implementation of drones will benefit from an ...understanding of the current system and that existing transport solutions should be optimized before drone solutions are considered. It focuses on carriers transporting biological material today by car along a traditional circular route. It aims to explore how the current transport service is organized, identify areas for improvement, and investigate carriers' perceptions of how drones could be integrated into or substituted for their services. Methods: A mixed-methods approach was applied, combining a questionnaire, shadowing of nine transport trips, semi- structured interviews, and time assessments. Results: The carriers shared insights into how to optimize existing transport solutions in terms of structure, culture, attitudes, and overall functionality. Most carriers expressed in the questionnaire that they were little involved in innovation work. The time assessment revealed that not the driving times, but the loading times had the highest deviations from plans and thus represented the area with the greatest potential for simple improvements. Questions about the use and organizational impact of drones are generated, and their prospects are discussed from a broad sociotechnical perspective. Conclusion: Our concept was to broaden our understanding of implementing drones into existing systems in a fairly simple setting. Although improved logistics may take place without complex processes, future research opportunities such as the impact of drones on organizational processes and social dynamics in the adoption of drones may be needed if more complex systems are involved. The paper proposes experimenting with, and learning from, transport with "road vehicles" and drones in combination and suggests that improvements should be made to existing transport solutions before drones are implemented. Keywords: logistics, transportation of laboratory samples, reconfiguration, sociotechnical systems, participation
Background
Beginning in 2008, metal-on-metal prostheses have been in the spotlight owing to much higher revision rates than expected. Adverse local tissue reactions have been well described in the ...literature as potential complications.
Methods
Between 2012 and 2013, 13 patients with metal-on-metal total hip replacements were evaluated clinically and radiologically and with laboratory samples. The same tests were repeated between 2015 and 2016 on eight patients to assess any changes. In the laboratory assessment, we searched for chromium, cobalt, molybdenum, and nickel in blood and urine samples over 24 h.
Results
Clinical assessment has shown good score in all patients except one. On a second examination, between 2015 and 2016, all patients obtained results similar to those obtained in the first assessment, except a patient, who reported a recent fall. In the radiological assessment between 2012 and 2013, results were optimal, apart from a case of aseptic mobilization. The patients reassessed 3 years after the first examination showed radiological results similar to those previously obtained, apart from a patient, who showed signals of mobilization. Metal levels found in their blood decreased in most cases after 3 years. Urine levels of nickel increased in five subjects, and chromium levels increased in four, but levels of cobalt and molybdenum decreased in four patients.
Conclusion
It could be hypothesized that the decreasing trend of metal ion levels is associated with a stable wear status. On the contrary, a progressive increase in metal ion levels must be considered as early proof of implant loosening.
We present results of goniometric photometry of different samples at extremely small phase angles using a new laboratory setup with a laser light source (
λ=0.63
μm). No opposition effect of carbon ...soot is found in the range 0.008–1.5°; whereas, MgO deposits and very disperse porous SiO
2 powder demonstrate a narrow brightness spike of significant amplitude. We find a strong dependence of phase curve slope in the range on albedo when studying mixtures of white chalk and carbon soot. These measurements as applied to interpretation of opposition effect observed for Kuiper belt objects suggest that the albedo of these objects cannot be small. Size particle separates of olivine reveal prominent opposition spikes independent of the particle size. Spherical particles with a diameter near 50
μm show significant differences in their scattering behavior depending on whether they form a monolayer or thick particulate surfaces. The latter show a sharp opposition surge unlike the monolayer. Except for the monolayer of spheres, no particulate surface in our measurements yet exhibits phase curve rounding as the phase angle approaches zero.
Measuring the cross-anisotropy of hot-mix asphalt Islam, Md Rashadul; Ahmed, Mesbah U.; Tarefder, Rafiqul A.
The international journal of pavement engineering,
03/2016, Letnik:
17, Številka:
3
Journal Article
Recenzirano
This study measures the cross-anisotropy of gyratory, kneading and field-compacted hot-mix asphalt samples of two sizes. One set of cube samples were subjected to compression through the top face and ...the other set through the side face. In addition, two sets of beam samples were tested for flexure stiffness using load on both the top and side faces. Results show that the side faces can sustain an average compressive stress of 0.89, 0.91 and 0.77 times of the top faces for kneading, gyratory and field-compacted cube samples, respectively. The average flexure stiffness of the side face is 0.85 times of that of the top face. For comparison, finite element model (FEM) was developed to predict pavement stress-strain under wheel load. In addition, stress-strain data from a field-instrumented pavement section on Interstate 40 in New Mexico were collected. The FEM-simulated vertical stress shows a close match with collected stress at cross-anisotropy value of 0.8.
A marketing innovation is the key factor of any product to be launched in the consumer market. This research anticipates that had already been patented worldwide launch of a product (non- chemical) ...pharmaceutical industry to be called KITLAB, which will change for the better the procedure and user form to collect a single sample of feces or urine be taken for laboratory examination. The objective of this paper is to show product innovation to make a collection of these hygienically correct. The methods and techniques are their main advantages it has over its competitors, since it enables the user to make a collection without handling, that is, that a sample collection (feces/urine), is made by everyone (men/women, adults/children) hygienically, in a very different way of unhygienic today make such collections, which are, at best, made directly on the floor without any care with possible contamination toilet that such unsuitable sites can provide samples. The results observed in a study commissioned assessment of market viability showed that the product had total public approval , and in addition , he has numerous competitive advantages over other existing competing products in the market because its use eliminates the so inconvenient, self - embarrassing and unhygienic way of making today a collection of stools, and more, it will give the user a personal satisfaction and comfort, finally, this product will eliminate the so uncomfortable handling necessary that still exists today.
El objetivo general de acción de este proyecto es ampliar una mediateca digital consistente en imágenes de muestras histopatológicas obtenidas en la 2da. Cátedra de Biología Celular, Histología y ...Embriología de la Facultad de Ciencias Medicas Universidad Nacional de Córdoba, Argentina. Se proponen tres líneas de trabajo principales: 1- integración de imágenes y documentos científicos (abstract de artículos) mediante el uso de términos ontológicos, 2- articulación del listado de imágenes y documentos científicos con herramientas de acceso a la información multimedia (imágenes y texto), 3- incorporación de una traducción simi-automática ingles-español usando herramientas libres de traducción automática de lengua origen castellano a lengua de origen ingles. Creemos que la asociación de diferentes herramientas de gestión del conocimiento permitirán ampliar una mediateca digital de muestras de laboratorio correspondientes a resultados de nuestros de trabajos de investigación subsidiados por organismos oficiales. También para que los contenidos de este proyecto estén disponibles para un amplio usuario de las Ciencias de la Salud con diferentes niveles de alfabetización funcional. Por último nuestro proyecto permitirá la inclusión de profesionales de la Escuela de Bibliotecología y de la Facultad de Lenguas de nuestra Universidad Pública.
One of the most important aspects of the practice of avian medicine and surgery is the ability to safely collect a variety of specimens from the bird for use in the laboratory setting. The ...indications, contraindications, techniques, and concerns for specimen handling for samples collected from the peripheral blood, bone marrow, respiratory system, and gastrointestinal system are presented. No attempt has been made to discuss the interpretation of results obtained from these techniques. Additionally, use of other ancillary diagnostic techniques, such as endoscopy, diagnostic imaging, and electrocardiography, are beyond the scope of this presentation.
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