Investigating Fatigue Performance on the Foamed Asphalt Specimens Generated Using Different Foam Properties

An evaluation of fatigue resistance for foamed asphalt mixture is very demanding since the binder is not continuously distributed on the aggregate surface and this mixtures contains water, the content of which dramatically affects the mechanical properties. This paper discusses the results of laboratory fatigue testingon the foamed asphalt mixtures in which the specimens are generated using three different foamed bitumen properties. Foamed bitumen as the binder was produced at three different foaming water content (FWC) at a temperature of 180oC using a 70/100 pen. The aggregates were mechanically mixed with foamed bitumen using a Hobart mixer. The resulting mixtures were then compacted using a gyratory compactor to generatespecimen with diameter of 100 mm. The specimens were fatigue tested at various stress levels at a temperature of 20oC following a curing period of 3 days at 40oC. Overall, fatigue performance of foamed asphalt can be identified based upon both stress and strain for mixtures produced at FWC 1%, 5%, and 10%

Un primer curso sobre Variable Compleja

Este texto tiene como propósito presentar los aspectos introductorios de las funciones de variable compleja para que sirva como texto orientador de los académicos interesados en este tema y, en particular, de los cursos que sobre esta área se ofrecen en los Programas de: Licenciatura en Matemáticas, Física y, parcialmente, Ingeniería Electrónica de la Universidad de Nariño

A GPU-Enabled, High-Resolution Cosmological Microlensing Parameter Survey

In the era of synoptic surveys, the number of known gravitationally lensed quasars is set to increase by over an order of magnitude. These new discoveries will enable a move from single-quasar studies to investigations of statistical samples, presenting new opportunities to test theoretical models for the structure of quasar accretion discs and broad emission line regions (BELRs). As one crucial step in preparing for this influx of new lensed systems, a large-scale exploration of microlensing convergence-shear parameter space is warranted, requiring the computation of O(10^5) high resolution magnification maps. Based on properties of known lensed quasars, and expectations from accretion disc/BELR modelling, we identify regions of convergence-shear parameter space, map sizes, smooth matter fractions, and pixel resolutions that should be covered. We describe how the computationally time-consuming task of producing ~290000 magnification maps with sufficient resolution (10000^2 pixel/map) to probe scales from the inner edge of the accretion disc to the BELR can be achieved in ~400 days on a 100 teraflop/s high performance computing facility, where the processing performance is achieved with graphics processing units. We illustrate a use-case for the parameter survey by investigating the effects of varying the lens macro-model on accretion disc constraints in the lensed quasar Q2237+0305. We find that although all constraints are consistent within their current error bars, models with more densely packed microlenses tend to predict shallower accretion disc radial temperature profiles. With a large parameter survey such as the one described here, such systematics on microlensing measurements could be fully explored.Comment: 30 pages, 3 figures, accepted for publication in Ap

A Consistent Picture Emerges: A Compact X-ray Continuum Emission Region in the Gravitationally Lensed Quasar SDSS J0924+0219

We analyze the optical, UV, and X-ray microlensing variability of the lensed quasar SDSS J0924+0219 using six epochs of Chandra data in two energy bands (spanning 0.4-8.0 keV, or 1-20 keV in the quasar rest frame), 10 epochs of F275W (rest-frame 1089A) Hubble Space Telescope data, and high-cadence R-band (rest-frame 2770A) monitoring spanning eleven years. Our joint analysis provides robust constraints on the extent of the X-ray continuum emission region and the projected area of the accretion disk. The best-fit half-light radius of the soft X-ray continuum emission region is between 5x10^13 and 10^15 cm, and we find an upper limit of 10^15 cm for the hard X-rays. The best-fit soft-band size is about 13 times smaller than the optical size, and roughly 7 GM_BH/c^2 for a 2.8x10^8 M_sol black hole, similar to the results for other systems. We find that the UV emitting region falls in between the optical and X-ray emitting regions at 10^14 cm < r_1/2,UV < 3x10^15 cm. Finally, the optical size is significantly larger, by 1.5*sigma, than the theoretical thin-disk estimate based on the observed, magnification-corrected I-band flux, suggesting a shallower temperature profile than expected for a standard disk.Comment: Replaced with accepted version to Ap

Implementation of a low cost prototype for electrical impedance tomography based on the integrated circuit for body composition measurement AFE4300

Electrical impedance tomography (EIT) is a technique of image reconstruction of the electrical conductivity distribution in a tissue or region under observation. An electrical system for EIT comprises complex hardware and software modules, which are designed for a specific application which requires that the system to be able to detect conductivity variations within the study object. The Front-End for body composition measurement, AFE4300 from Texas Instruments allows a minimal implementation of an electrical impedance tomography system. It is the main device in the development of the EIT system presented in this paper, this device injects the current signal and measures the tensions generated on the study region boundary by 8 electrodes, the image reconstruction software was developed on the National Instruments platform Labview. The system includes a microcontroller PIC16F886 to configure the 8 channels for the definition of the patterns of injection and measurement of signals, also defines the current signal frequency and the bluetooth communication with the computer for the image reconstruction. The developed system was validated by a planar resistive phantom (CardiffEIT phantom), obtaining a stable voltage measurement every 50 ms per pair of electrodes, and a signal to noise ratio (SNR) maximum of 71.8 dB, for a current signal of 50 kHz. Additionally, tests were carried out in a saline tank with a concentration of 4 g/L, the developed system can simultaneously estimate the presence of conductive and non-conductive disturbances into the tank. CopyrightPeer ReviewedPostprint (published version

Ontwikkeling snelle meetmethode ter bepaling van ammoniakemissiereductie van vloergebonden maatregelen = Development of a fast measurement method for the determination of ammonia emission reduction from floor related measures

This report describes different methods for determination of the effect of different floor types on (ammonia) emission. One method, the box method, has been further evaluated

Gravitational Microlensing of a Reverberating Quasar Broad Line Region - I. Method and Qualitative Results

The kinematics and morphology of the broad emission line region (BELR) of quasars are the subject of significant debate. The two leading methods for constraining BELR properties are microlensing and reverberation mapping. Here we combine these two methods with a study of the microlensing behaviour of the BELR in Q2237+0305, as a change in continuum emission (a "flare") passes through it. Beginning with some generic models of the BELR - sphere, bicones, disk - we slice in velocity and time to produce brightness profiles of the BELR over the duration of the flare. These are numerically microlensed to determine whether microlensing of reverberation mapping provides new information about the properties of BELRs. We describe our method and show images of the models as they are flaring, and the unlensed and lensed spectra that are produced. Qualitative results and a discussion of the spectra are given in this paper, highlighting some effects that could be observed. Our conclusion is that the influence of microlensing, while not strong, can produce significant observable effects that will help in differentiating the properties of BELRs.Comment: 17 pages, 14 low resolution figures, 1 table, accepted for MNRAS. v2: Corrected velocities p16, 8 to 0.08, 9 to 0.0

Actualidad del sistema productivo tradicional de panela en Colombia : análisis de mejoras y alternativas tecnológicas.

(Eng) Panela, or unrefined non centrifugal brown sugar, is a natural sweetener obtained from the evaporation and concentration of sugarcane juice (Saccharum officinarum), essential for food security, agricultural economics and rural development in Latin America. The degree of process efficiency and the marketing evaluation for this product in Colombia is as yet incipient. This study presents the traditional system for panela production, from a technical and engineering perspective, also highlighting some aspects of qual - ity and innovation. Improvements to the traditional furnace design, extraction and milling, clarification, and heat transfer are analyzed. By criteria of competitiveness and efficiency, was evidenced the need to continue the development and transfer of innovative technological alternatives. It is also imperative the participation of the panela producers in new and potential markets.(Spa) La panela es un edulcorante obtenido de la evaporación y concentración de los jugos de caña de azúcar (Saccharum officinarum), fundamental para la seguridad alimentaria, la economía agraria y el progreso rural en Latinoamérica. El grado de tecnificación de la agroindustria panelera en Colombia y la comer - cialización de sus productos derivados es hasta ahora incipiente. El presente estudio expone el sistema productivo tradicional de la panela desde una perspectiva técnica y de ingeniería, destacando además algunos aspectos de calidad e innovación. Se analizan las mejoras al diseño de la hornilla panelera tradi - cional, y opciones eficientes de extracción, clarificación, generación y transferencia de calor. Mediante criterios de competitividad y eficiencia, se evidencia la necesidad de continuar con el perfeccionamiento y la transferencia de alternativas tecnológicas innovadoras. Resulta también primordial la participación del sector panelero en mercados nuevos y potenciale