Development of a testing protocol for oil solidifier effectiveness evaluation

Chemical countermeasures for oil spill remediation have to be evaluated and approved by the U.S. Environmental Protection Agency before they may be used to remove or control oil discharges. Solidifiers are chemical agents that change oil from a liquid to a solid by immobilizing the oil and bonding the liquid into a solid carpet-like mass with minimal volume increase. Currently, they are listed as Miscellaneous Oil Spill Control Agent in the National Contingency Plan and there is no protocol for evaluating their effectiveness. An investigation was conducted to test the oil removal efficiency of solidifiers using three newly developed testing protocols. The protocols were qualitatively and quantitatively evaluated to determine if they can satisfactorily differentiate effective and mediocre products while still accounting for experimental error. The repeatability of the three protocols was 15.9, 5.1, and 2.7 %. The protocol with the best performance involved measuring the amount of free oil remaining in the water after the solidified product was removed using an ultraviolet–visible spectrophotometer and it was adopted to study the effect of solidifier-to-oil mass ratio, mixing energy, salinity, and beaker size (i.e., area affected by the spill) on solidifier efficiency. Analysis of Variances were performed on the data collected and results indicated that the beaker size increased spreading, which reduced removal efficiency. Mixing speed appears to impart a ceiling effect with no additional benefit provided by the highest level over the middle level. Salinity was found to be mostly an insignificant factor on performance

Experimental comparison of control strategies for trajectory tracking for mobile robots

The purpose of this paper is to implement, test and compare the performance of different control strategies for tracking trajectory for mobile robots. The control strategies used are based on linear algebra, PID controller and on a sliding mode controller. Each control scheme is developed taking into consideration the model of the robot. The linear algebra approaches take into account the complete kinematic model of the robot; and the PID and the sliding mode controller use a reduced order model, which is obtained considering the mobile robot platform as a black-box. All the controllers are tested and compared, firstly by simulations and then, by using a Pioneer 3DX robot in field experiments.Fil: Capito, Linda. Escuela Politécnica Nacional; EcuadorFil: Proaño, Pablo. Escuela Politécnica Nacional; EcuadorFil: Camacho, Oscar. Escuela Politécnica Nacional; EcuadorFil: Rosales, Andrés. Escuela Politécnica Nacional; EcuadorFil: Scaglia, Gustavo Juan Eduardo. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Ingeniería Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentin

On Linearity, Phasors and Steady-State Response of Electrical Circuits

This note addresses the widespread and often unquestioned assumption that a linear circuit supplied by a sinusoidal input (voltage or current) always results in a sinusoidal output (current or voltage). Likewise, it is generally assumed that only nonlinear circuits can generate harmonic distortion. Based on the linearity assumption, the analysis of power systems properties is usually carried out using Fourier analysis and phasors. Such analyses typically neglect the transients and initial conditions. Two elementary examples are exploited to show that linearity alone is not sufficient to guarantee a sinusoidal steady- state response. It is necessary to invoke some additional assumptions. However, these assumptions contradict the underlying philosophy of phasors or are difficult to accomplish physics-wise

Domino Effect in Allosteric Signaling of Peptide Binding

While being a thoroughly studied model of dynamic allostery in a small protein, the pathway of signal transduction in the PDZ3 domain has not been fully determined. Here, we investigate peptide binding to the PDZ3 domain by conventional and fully data-driven analyses of molecular dynamics simulations. First, we identify isoleucine 37 as a key residue by widely used computational procedures such as cross-correlation and community network analysis. Simulations of the Ile37Ala mutant show disruption of the coordinated movements of spatially close regular elements of secondary structure. Then, we employ a recently developed unsupervised, data-driven procedure to determine an optimized reaction coordinate (slowest-relaxation eigenvector) of peptide binding. We use this reaction coordinate to improve sampling by restarting additional simulations from the transition state region. Significant differences in the distributions of some of the pairwise residue distances in the bound and unbound states emerge from the projection onto the optimized reaction coordinate. The unsupervised analysis shows that allosteric signaling is transduced from the β2 strand, which forms part of the peptide binding site, to the spatially adjacent β3 and β4 strands, and from there to the α3 helix. The domino-like transmission of a (peptide binding) signal along β strands and α helices that are close in three-dimensional space is likely to be a general mechanism of allostery in single-domain proteins

El acuerdo interinstitucional en la práctica peruana de derecho internacional: Reexamen de “the concept of treaty in international law” de Klabbers

El derecho internacional ofrece a la comunidadinternacional varios tipos de instrumentosinternacionales, y no todos han sidoexplorados completamente por la doctrina. Enese contexto, el presente artículo tiene comoobjetivo reexaminar el análisis planteadopor Jan Klabbers en su libro “The Conceptof Treaty in International Law” (1996) sobrelos administrative agreements, que en lalegislación peruana reciben el nombre de“acuerdos interinstitucionales” (AI). Enese sentido, se revisarán cuatro críticas queKlabbers plantea sobre tales tipos de acuerdos:i) la textura abierta de la definición de Estadoen la Convención de Viena sobre el Derechode los Tratados (CVDT); ii) el rechazo haciala hipótesis sobre la subjetividad internacionalde las entidades públicas y la existencia de untercer orden jurídico distinto al derecho internoy al derecho internacional; iii) las dificultadesde reconciliar los AI con la teoría de laresponsabilidad internacional; y iv) la facilidadde repudio de los administrative agreements.Siguiendo este propósito, el artículo explorasoluciones a los principales problemasidentificados por el jurista holandés, revisandoesos dilemas a través del caso del AI peruano,mediante una metodología analítica

Traceability in the Electronics Manufacturing Industry: A state-of-the-art review and a case study

Industry 4.0 constitutes a major transformation of traditional factories. Innovative technologies are changing the way companies deal with the production process and supply chain management, and how organizations implement sustainable models. Traceability is a key component of the supply chain, hence the application of some of the drivers of the Fourth Industrial Revolution has a significant impact, consequently leading to the optimization of operations and the increase of efficiency and reliability. The present thesis analyzes the current industrial context with respect to traceability, focusing, particularly, on the electronics manufacturing industry. The project introduces a general framework for traceability and a comprehensive state-of-the-art review that includes the most relevant technologies in the field. The previous theoretical background lays the foundations to perform a case study of a real company, in which, from a descriptive perspective, the traceability implementation is evaluated, discussing the potential utilization of the considered technologies. Finally, some general conclusions regarding traceability in the electronics manufacturing industry and its prospective development in the paradigm of Industry 4.0 are presented