Phase only transmit beamforming for spectrum sharing microwave systems

This paper deals with the problem of phase-only transmit beamforming in spectrum sharing microwave systems. In contrast to sub-6 GHz schemes, general microwave systems require a large number of antennas due to its huge path loss. As a consequence, digital beamforming needs a large number of computational resources compared to analog beamforming, which only needs a single radio-frequency chain, results the less computational demanding solution. Analog schemes are usually composed by a phase shifter network whose elements transmit at a certain fixed power so that the system designer shall compute the phase values for each element given a set of directions. This approach leads to non-convex quadratic problems where the traditional semidefinite relaxation fails to deliver satisfactory outcomes. In order to solve this, we propose a nonsmooth method that behaves well in several scenarios. Numerical evaluations in different spectrum sharing scenarios, which show the performance of our method, are provided.Peer ReviewedPostprint (author's final draft

Influence of the chain length of surfactant in the modification of zeolites and clays. Removal of atrazine from water solutions

Influence of the chain length of surfactant in the modification of zeolites and clays. Removal of atrazine from water solutionsRemoval potentials of a surfactant modified zeolite (SMZ) and clay (SMC) for atrazine adsorption were evaluated. Materials were modified with hexadecyl trimethyl ammonium bromide (HDTMABr) and benzyl octadecyl dimethyl ammonium (BODA) chloride considering the critical micellar concentration (CMC) of each one (0.94 and 0.041 meq/L, respectively). The influence of the surfactant was analyzed in detail, particularly the formation of surfactant layers (complete or partial) connected with the length of the surfactant tail (16 and 18 methyl groups or number of carbons in the chain). Raw materials were characterized by XRD and Fourier transform infrared spectroscopy (FTIR), SMZ and SMC were analyzed by FTIR. Results obtained from kinetic adsorption experiments shown that equilibrium time is less for materials modified with HDTMA (8 h) than materials with BODA (10 and 12 h). Materials modified with the largest chain surfactant (BODA) showed more resistance to atrazine masse transference. The chemisorption was presented in the adsorption mechanisms of atrazine and adsorbent materials. Based on the results of adsorption isotherms Langmuir isotherms showed the better correlation coefficients value. The qmax is greater for materials modified with BODA (0.9232 and 4.2448 mg/g) than for materials modified with HDTMA (0.6731 and 3.9121 mg/g). Therefore, SMZ and SMC modified with the largest chain surfactant has more affinity for the pesticide. The removal process at high concentration of atrazine depends of the partition process but at lower concentration, it occurs not only by this process but also by absorption process

Influence of the chain length of surfactant in the modification of zeolites and clays. Removal of atrazine from water solutions

Influence of the chain length of surfactant in the modification of zeolites and clays. Removal of atrazine from water solutionsRemoval potentials of a surfactant modified zeolite (SMZ) and clay (SMC) for atrazine adsorption were evaluated. Materials were modified with hexadecyl trimethyl ammonium bromide (HDTMABr) and benzyl octadecyl dimethyl ammonium (BODA) chloride considering the critical micellar concentration (CMC) of each one (0.94 and 0.041 meq/L, respectively). The influence of the surfactant was analyzed in detail, particularly the formation of surfactant layers (complete or partial) connected with the length of the surfactant tail (16 and 18 methyl groups or number of carbons in the chain). Raw materials were characterized by XRD and Fourier transform infrared spectroscopy (FTIR), SMZ and SMC were analyzed by FTIR. Results obtained from kinetic adsorption experiments shown that equilibrium time is less for materials modified with HDTMA (8 h) than materials with BODA (10 and 12 h). Materials modified with the largest chain surfactant (BODA) showed more resistance to atrazine masse transference. The chemisorption was presented in the adsorption mechanisms of atrazine and adsorbent materials. Based on the results of adsorption isotherms Langmuir isotherms showed the better correlation coefficients value. The qmax is greater for materials modified with BODA (0.9232 and 4.2448 mg/g) than for materials modified with HDTMA (0.6731 and 3.9121 mg/g). Therefore, SMZ and SMC modified with the largest chain surfactant has more affinity for the pesticide. The removal process at high concentration of atrazine depends of the partition process but at lower concentration, it occurs not only by this process but also by absorption process

Formulación de una Conserva de Atún (Euthynnus (Katsuwonus) pelamis) y Ají Picante (Capsicum annuum L) como alternativa Industrial en el sector atunero.

Este proyecto aplicado tiene como objetivo diseñar una conserva de atún en envase TFS (Tin Free Steel) con un sabor característico picante, del ají chivato (Capsicum annuum L) el cual es un producto autóctono colombiano; La inclusión del ají en esta conserva le brinda un diferencial en comparación con las conservas de atún que hoy día se encuentran en el mercado que solamente vienen con agua y/o aceite. Se realiza bajo los parámetros y lineamientos establecidos en el Codex Stan 70-1981 y la resolución colombiana 0148 de 2007 “Por la cual se establece el reglamento técnico sobre los requisitos que debe cumplir el atún en conserva y las preparaciones de atún que se fabriquen, importen o exporten para el consumo humano.” Para ello se elaboró un programa de diseño y desarrollo de un nuevo producto, que se probó con un prototipo, en el cual participan trabajadores de una empresa del departamento del Atlántico que cuentan con la capacitación y experiencia técnica y profesional para el desarrollo de este tipo de producto alimenticio.This applied project aims to design a canned tuna in a TFS (Tin Free Steel) container with a characteristic spicy flavor, from the chivato pepper (Capsicum annuum L) which is a native Colombian product; The inclusion of chili in this canned food gives it a differential compared to the canned tuna that are currently on the market that only come with water and / or oil. It will be carried out under the parameters and guidelines established in Codex Stan 70-1981 and Colombian resolution 0148 of 2007 “that is the technical regulation is established on the requirements that canned tuna and the tuna preparations that are manufactured must meet, import or export for human consumption. " For this, a design and development program for a new product will be designed, which will be tested with a prototype, in which workers from a company in the department of Atlántico participate, who have the training and technical and professional experience to develop this type of food product

Paternity allocation in a mutant Heliothis virescens colony

Tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), females can copulate multiple times creating the possibility for sperm competition. We used a colony lacking wild pigmentation on the wings (albino-type) for an experiment in which females double mated. Females copulated 2 days apart with two, 2-day-old males, one albino-type and one wild-type, or in the opposite sequence. A third of the females produced offspring from the first mate, and this group was significantly biased toward producing albino-type compared to wild-type progeny. A fourth of the females produced offspring from the second male exclusively and within this group was a significant bias toward wild-type compared to albino-type progeny. Almost half of the females produced offspring sired in equal proportions by both males simultaneously or in alternated paternities throughout all the reproductive life. These results suggest that regardless of the order in which moths mated, wild-type sperm had potential superior competitiveness. Therefore, sperm precedence is not the main driving force behind the paternity allocation mechanism in this strain of tobacco budworm

The impact of a mobile phone-delivered digital financial education program on financial behavior among Hispanics

We explored the potential of digital financial education programs among Hispanic populations, through the design and evaluation of a mobile phone delivered digital program called Mind Your Money (MYM). This program sought to improve financial knowledge and behavior among low- to-moderate income Hispanics residing in the Greater Los Angeles area. We assessed the program through a randomized controlled trial with a wait-list control group. Our digital financial education program had a higher retention rate than comparable in-person financial coaching programs. We found that our program had a positive statistical significant effect on financial capability. Participants who completed program activities were more likely to have a budget/spending plan and felt more confident about their ability to pay for unexpected expenses

Determination of nevirapine in the presence of cucurbit(7)uril with a gold electrode

The electrochemical oxidation of nevirapine, an anti-HIV drug, at a gold electrode was studied by voltammetric techniques. Nevirapine showed a signal that interfered with a working electrode wave. This interference was solved by the use of cucurbit(7)uril allowing nevirapine to be determined in tablets (80.4 % recovery, presence of stavudine and lamivudine) and urine (98.4 %)