Research study of droplet sizing technology leading to the development of an advanced droplet sizing system

An instrument to measure the size and velocity of droplets was developed. The instrument uses one of two techniques, as appropriate. In the first technique two small laser beams of one color identify the center of a larger laser beam of a different color. This defines a region of almost uniform intensity where the light scattered by the individual droplets can be related to their size. The first technique uses the visibility of a Doppler burst and validates it against the peak intensity of the signal's pedestal. Results are presented for monodisperse, bimodal, trimodal, and polydisperse sprays produced by the Berglund-Liu droplet generator and a pressure nozzle. Size distributions of a given spray obtained using three different size ranges show excellent self-consistency in the overlapping region. Measurements of sprays of known characteristics exhibit errors in the order of 10%. The principles of operation and design criteria of the instrument are discussed in great detail

Self collimation of ultrasound in a 3D sonic crystal

We present the experimental demonstration of self-collimation (subdiffractive propagation) of an ultrasonic beam inside a three-dimensional sonic crystal. The crystal is formed by two crossed steel cylinders structures in a woodpile-like geometry disposed in water. Measurements of the 3D field distribution show that a narrow beam which diffractively spreads in the absence of the sonic crystal is strongly collimated in propagation inside the crystal, demonstrating the 3D self-collimation effect.Comment: 3 figures, submitted to Applied Physics Letter

Impacto de las Abejas (Apis mellifera L.) Como Agentes Polinizadores en el Rendimiento del Cultivo de Zucchini (Cucurbita pepo L.) en el Canton Riobamba, Provincia de Chimborazo

The impact of bees (Apis mellifera L.) as pollinators in the yield of the zucchini (Cucurbita pepo L.) crop in the Riobamba canton, Chimborazo province, was evaluated using a Randomized Complete Block Design (RCBD). This was done using three treatments and three repetitions. The treatments evaluated were: the zucchini cultivation inside the micro tunnel covered with entomological mesh with the presence of bees, the zucchini cultivation inside the micro tunnel covered with anti aphids mesh without the presence of bees, and the open field zucchini cultivation. The evaluated parameters were number of days to the appearance of the fruits, percentage of fertilized and unfertilized flowers, number of fruits per plant, size of fruits, diameter of fruits, weight of fruit, and yield in kg / ha per treatment. The best results achieved in most parametersthat were evaluated such as the percentage of flowering, number of fruits per plant, size of fruit in cm, diameter of fruit in cm, weight of the fruit in grams, yield in kg/ha by treatment, and economic analysis were obtained with the presence of bees (Apis mellifera L.) as pollinating agents in the tunnel. This is in addition to meshes during the flowering stage of the zucchini crop, with an average yield of 14.9 tn/ha.Se evaluó el impacto de las abejas (Apis mellifera L.) como agentes polinizadores en el rendimiento del cultivo de zucchini (Cucurbita pepo L.) en el cantòn Riobamba, provincia de Chimborazo. Para llevar a cabo esta evaluación se utilizó un diseño de bloques completos a azar (DBCA), con tres tratamientos y tres repeticiones. Los tratamientos evaluados fueron: El cultivo de zucchini dentro del micro túnel cubierto con malla entomológica con presencia de abejas, el cultivo de zucchini dentro del micro túnel cubierto con malla antiáfidossin presencia de abejas y el cultivo de zucchini a campo abierto. Los parámetros evaluados fueron número de días transcurridos después de la aparición de los frutos, porcentaje de flores fecundadas y no fecundadas, número de frutos por planta, tamaño de frutos, diámetro de frutos, peso del fruto y rendimiento en kg/ha por tratamiento. Los mejores resultados alcanzados en la mayoría de los parámetros evaluados como el porcentaje de floración, número de frutos por planta, tamaño de fruto en (cm), diámetro de fruto en (cm), peso del fruto en gramos, rendimiento en kg/ha por tratamiento y análisis económico, se obtuvieron con la presencia de las abejas (Apis mellifera L.) como agentes polinizadores en el túnel con mallas durante la etapa de floración del cultivo de zucchini, con un rendimiento en promedio de 14.9 tn/ha

The Indoor Radon Concentration within the Tunnels of the Cholula Pyramid Through a Nuclear Tracks Methodology

Global organizations, including the World Health Organization (WHO), the Environmental Protection Agency of the United States (US-EPA) and the European Atomic Energy Community (EURATOM) recognize that radon gas as one of the main contributors to environmental radiation exposure for humans. Accordingly, a study and analysis of the indoors radon concentrate in the Cholula Pyramid contributes to understand the Radon dynamic inside of the Pyramid tunnels and to evaluate the radiological health risk to visitors, archaeologists, anthropologists and persons who spend extended periods inside the Pyramid. In this paper, the radon measurements along the Pyramid tunnels are presented. The Nuclear Track Methodology (NTM) was chosen for the measurements, using a close end-cup device developed at the Dosimetry Application Project (DAP) of the Physics Institute UNAM, following very well established protocols for the chemical etching and reading with the Counting Analysis Digital Imaging System (CADIS). The Cholula Pyramid consists of eight stages of constructions, each built in different periods of time. Cholula Pyramid is recognized as the pyramid with the largest base in the World, with 400 meters per side and 65 meters high. The tunnels of the pyramid were built in 1931 by architect Ignacio Marquina, with the aim of exploring and studying the structure. The results show an important indoor radon concentration in the measured tunnels, several times higher than levels recommended by United States Environmental Protection Agency (US-EPA). The recommendation will be to mitigate the radon concentration levels, in order to avoid unnecessary exposition to the people

Analysis and characterization of neutron scattering of a Linear Accelerator (LINAC) on medical applications.

In several theoretical and experimental studies, the topic of the undesirable generation of photoneutrons in rooms where a linear accelerator (LINAC) operates has been discussed. When energies above 10 MeV are used to produce X-rays and give radiotherapy treatment to patients resulting in additional radiation to patients. Accordingly, an analysis and characterization of the neutron scattering distribution on different zones in a treatment room contributes to evaluate the radiological health risk to patients, technical and other workers involved in treatment. For the evaluation, a device developed at the PAD-IFUNAM formed by a CR-39 detector enclosed by two 3mm thick acrylic plates was employed. To avoid environmental contamination, the CR-39 and the acrylics plates are enclosed in a round plastic box. Sixteen of these devices were settled in different places inside the treatment room, where a linear accelerator is used. The results show a significant concentration of neutron scattering in areas near the head of irradiation. The recommendation will be to evaluate the neutron scattering concentration in all rooms that’s operates a LINAC in order to verify the radiological health risk and to mitigate the neutron scattering when concentration levels are to high like those in our case, in order to avoid unnecessary exposition to patients and personnel in general

Higgs Sector Radiative Corrections and s-Channel Production

Higgs boson mass sum rules of supersymmetric models offer attractive targets for precision tests at future muon colliders. These sum rules involve the gauge boson masses as well as the masses of the Higgs boson states which can be precisely measured in the $s$-channel production process at a muon collider. These measurements can sensitively probe radiative corrections to the Higgs boson masses as well as test for CP-violation and nonminimality of the Higgs sector.Comment: 4 pages, 2 figures, published versio

Growing monitoring in sea cages: TS measurements issues

Hydroacoustic monitoring of fish growing in sea cages needs of an accurate relationship between fish size and target strength (TS) for every species of commercial interest. We discuss the conditions for TS measurement in near range conditions in sea cages for the case of the dorsal and ventral aspects of gilthead sea bream and bluefin tuna. Gilthead sea bream dorsal and ventral TS distributions, obtained with a split beam echosounder, are unimodal and the same results are derived for single beam data analysis when specific processing threshold criteria are applied. The expected linear relationship between the average TS and the logarithm of fish length is only found for the ventral case, being more accurate the uncompensated TS single beam analysis, probably due to near range errors. Bluefin tuna dorsal measurements performed in a fattening farm from February to July did not show a significant variation of TS distributions, and we propose a synchronized system of echosounder and video recordings, in order to relate target strength and orientation and size of specific tuna in the acoustic beam. Preliminary results indicate that only ventral TS values correlate properly with tuna size