Improved polymer solar cell performance by engineering of cathode interface

By engineering the interface between the intermediate photoactive layer and the cathode aluminum (Al) electrode, through the introduction of ultra-thin layers of various materials, in a standard\ud bulk heterojunction (BHJ) polymer solar cell (PSC) fabricated of regioregular poly(3-hexylthiophene)(rr-P3HT) and phenyl-C61-butyric acid methyl ester (PCBM), the power conversion efficiency (PCE) has\ud been effectively improved. The devices fabricated using individual single interlayer of bathocuproine (BCP), lithium fluoride (LiF) and Buckminster fullerene C60 have shown optimal efficiencies of ∼2.40%, ∼3.21% and ∼1.92% respectively. Further improvement of the photovoltaic efficiency was achieved by introducing a composite bilayer made of LiF in combination with BCP as well as with C60 at the BHJ/cathode interface. The best results were obtained by interposing a 9 nm of C60 interlayer in combination with a 0.9 nm\ud thick LiF layer, with the PCE of the PV cells being effectively increased up to 3.94% which represents an improvement of 23% as compared to the standard device with LiF interlayer alone. The photocurrent density (Jsc) versus voltage (V ) characteristic curves shows that the increase of the efficiency is essentially\ud due to an increase in Jsc. Moreover, all the sets of devices fabricated using various interlayers over a certain range of thickness exhibit an optimum PCE that is inversely proportional to the series resistance of the PV cells. We presume that interposing a C60/LiF layer at the interface could repair the poor contact at\ud the electron acceptor/cathode interface and improve the charge career extraction from the BHJ

Causas y alternativas para el control de los procesos de erosión en las playas. Experiencias de las aplicaciones en la Región del Caribe

La mayoría de las playas a las que se asocian los principales núcleos turísticos del mundo están siendo afectadas, de forma generalizada, por los procesos de erosión. Con el interés de detener ese proceso se aplican diferentes alternativas, tanto legales: implementando normas, regulaciones y leyes con una función fundamentalmente preventiva, científicas: profundizando en el conocimiento del funcionamiento del sistema costero para establecer la relación causa-efecto entre los fenómenos que se producen y así garantizar la correcta identificación de las causas y magnitud de la erosión e ingenieras: encaminadas a la concepción y diseño de actuaciones para la protección y recuperación de la zona costera. En el presente artículo se muestran algunas experiencias de aplicaciones para el control de la erosión, donde se destaca la ejecución de la Alimentación Artificial de Arena, convertida, en el caso de las playas, en una solución de vanguardia para la regeneración y creación de litorales arenosos. En Cuba se han elaborado y ejecutado varios proyectos de Alimentación Artificial de Arena, destacándose el de un millón de metros cúbicos de arena vertidos en la playa de Varadero, principal polo turístico del país, considerado uno de los más exitosos y eficientes en la región del Caribe y en el ámbito mundial.Most of the beaches to those that associate the main tourist resort of the world are being affected, in a widespread way, for the erosion processes. With the interest of stopping that process are applied different alternative, so much legal: implementing norms, regulations and laws with a fundamentally preventive function, scientific: deepening in the knowledge of the operation of the coastal system to establish the relationship cause-effect among the phenomena that take place and this way to guarantee the correct identification of the causes and magnitude of the erosion and engineers: guided to the conception and design of performances for the protection and recovery of the coastal zone. Presently article some experiences of applications are shown for the control of the erosion, where it is stands out the execution of the Artificial Beach Nourishment, converted, in the case of the beaches, in a solution of vanguard for the protection, regeneration and creation of sandy coasts. In Cuba have been elaborated and executed several projects of Artificial Beach Nourishment, standing out the project of one million cubic meters of sand in the beach of Varadero, main tourist pole of country, considered one of the most successful and efficient executed in the region of the Caribbean and in the world environment

Relationship Between Carcass End Points and USDA Marbling Quality Grades: A Progress Report

The least square means for actual percent intramuscular fat (PIFAT), ultrasonically predicted percent intramuscular fat (UPIFAT), fat thickness (FAT), and ultrasound fat thickness (UFAT) were computed for each marbling quality grade as defined by UDSA (devoid, traces, slight, small, modest, moderate, and slightly abundant). PIFAT and UPIFAT least square means are statistically significantly different for all marbling quality grade classes except for the classes modest and moderate. FAT and UFAT least square means are significantly different for low marbling quality grades, such as traces, slight, and small but they are not different for modest, moderate and slightly abundant quality grades

Identificando actividades de matematización horizontal y vertical en un proceso de clasificación

La noción de matematización progresiva se expresa través de una secuencia generada por dos tipos de actividad matemática relacionadas reflexivamente: la matematización horizontal y la vertical (Treffers, 1987). Aunque, frecuentemente, la matematización horizontal se describe a través de la transformación de una situación problemática en un problema matemático propiamente dicho, en nuestro trabajo utilizaremos este concepto en un sentido más amplio que nos permitirá incluir situaciones de partida que sean de naturaleza ya matemática (Rasmussen, Zandieh, King & Teppo, 2005). Las actividades que pueden ser identificadas cuando se produce la matematización horizontal y la matematización vertical han sido descritas por Üzel y Mert Uyangör (2006)

CO2-Optimization of Post-Tensioned Concrete Slab-Bridge Decks Using Surrogate Modeling

[EN] This paper deals with optimizing embedded carbon dioxide (CO2) emissions using surrogate modeling, whether it is the deck of a post-tensioned cast-in-place concrete slab bridge or any other design structure. The main contribution of this proposal is that it allows optimizing structures methodically and sequentially. The approach presents two sequential phases of optimization, the first one of diversification and the second one of intensification of the search for optimums. Finally, with the amount of CO2 emissions and the differentiating characteristics of each design, a heuristic optimization based on a Kriging metamodel is performed. An optimized solution with lower emissions than the analyzed sample is obtained. If CO2 emissions were to be reduced, design recommendations would be to use slendernesses as high as possible, in the range of 1/30, which implies a more significant amount of passive reinforcement. This increase in passive reinforcement is compensated by reducing the measurement of concrete and active reinforcement. Another important conclusion is that reducing emissions is related to cost savings. Furthermore, it has been corroborated that for a cost increase of less than 1%, decreases in emissions emitted into the atmosphere of more than 2% can be achieved.Grant PID2020-117056RB-I00 funded by MCIN/AEI/10.13039/501100011033 and by "ERDF A way of making Europe".Yepes-Bellver, L.; Brun-Izquierdo, A.; Alcalá-González, J.; Yepes, V. (2022). CO2-Optimization of Post-Tensioned Concrete Slab-Bridge Decks Using Surrogate Modeling. Materials. 15(14):1-15. https://doi.org/10.3390/ma15144776115151

Quantum corrections to static solutions of Nahm equation and Sin-Gordon models via generalized zeta-function

One-dimensional Yang-Mills Equations are considered from a point of view of a class of nonlinear Klein-Gordon-Fock models. The case of self-dual Nahm equations and non-self-dual models are discussed. A quasiclassical quantization of the models is performed by means of generalized zeta-function and its representation in terms of a Green function diagonal for a heat equation with the correspondent potential. It is used to evaluate the functional integral and quantum corrections to mass in the quasiclassical approximation. Quantum corrections to a few periodic (and kink) solutions of the Nahm as a particular case of the Ginzburg-Landau (phi-in-quadro) and and Sin-Gordon models are evaluated in arbitrary dimensions. The Green function diagonal for heat equation with a finite-gap potential is constructed by universal description via solutions of Hermit equation. An alternative approach based on Baker-Akhiezer functions for KP equation is proposed . The generalized zeta-function and its derivative at zero point as the quantum corrections to mass is expressed in terms of elliptic integrals.Comment: Workshop Nonlinear Physics and Experiment; Gallipoli, 200