Evaluation of thermally and chemically reduced graphene oxide films as counter electrodes on dye-sensitized solar cells

Rodriguez-Perez, Manuel,Villanueva-Cab, Julio,Pal, Umapada Techno-Press 2017 Advances in nano research Vol.5 No.3

Graphene oxide (GO) was prepared by modified Hummer's method to produce reduced graphene oxide (RGO) following standard thermal and chemical reduction processes. Prepared RGO colloids were utilized to fabricate RGO films over glass and FTO coated glass substrates through drop-coating. A systematic study was performed to evaluate the effect of reduction degree on the optical and electrical properties of the RGO film. We demonstrate that both the reduction process (thermal and chemical) produce RGO films of similar optical and electrical behaviors. However, the RGO films fabricated using chemically reduced GO colloid render better performance in dye sensitized solar cells (DSSCs), when they are used as counter electrodes (CEs). It has been demonstrated that RGO films of optimum thicknesses fabricated using RGO colloids prepared using lower concentration of hydrazine reducer have better catalytic performance in DSSCs due to a better catalytic interaction with redox couple. The better catalytic performance of the RGO films fabricated at optimal hydrazine concentration is associated to their higher available surface area and lower grain boundaries.

In search of “Muda” through the TKJ Diagram. An analysis and Classification

( Manuel F. Suarez-barraza(phd) ),( Francisco G. Rodriguez-gonzalez(phd Candidate) ) 한국품질경영학회 2015 한국품질경영학회 학술대회 Vol.2015 No.2

Purpose. Muda is a Japanese term literally meaning futility, uselessness, idleness, superfluity, waste, wastage or wastefulness. The term was introduced by the Japanese engineer Taiichi Ohno of Toyota Motor Corporation in the 1960s. Therefore, reducing and minimizing Muda is an effective way to increase the operational efficiency and productivity of an organization’s processes. In turn, the technique known as the affinity or TKJ diagram represents a practical way of sorting data or ideas into groups classified by common patterns; it can be regarded as one of the new seven tools of quality. The purpose of this paper is to discover Muda by applying the affinity or TKJ diagram in Mexican organizations. Design/methodology/approach. An exploratory qualitative study was conducted. Using theoretical sampling, we identified and analyzed data from a kaizen training course. Each course workshop was organized by the consulting firm “Mi Empresa” and given to employees of various organizations in various sectors over three years from January 2012 to January 2015. In total, 36 KJ diagrams were obtained from 12 course workshops. Findings. The research provided the first evidence of Muda in Mexican organizations. The Muda of Ohno’s classification was confirmed, but new common patterns of Muda in 21st century organizations also arose. Furthermore, the TKJ diagram proved to be an effective tool of quality to detect it. Research limitations. This paper has the same limitations as all other qualitative research, including analysis subjectivity and questionable generalization of findings. It is also important to highlight that the 36 KJ diagrams yielded 1,026 Muda, a seemingly abundant figure. However, it is a small sample for the number of companies and processes to be found in Mexico. Practical implications (if possible). This paper may prove to be valuable for practitioners and managers involved in the operations and continuous improvement fields. Getting to know Muda in organizations is of great importance for continuously improving organizational processes. This classification will allow greater insight and easier detection. Originality/value. The study contributes to the limited existing literature on total quality management, lean thinking and kaizen and subsequently disseminates this information in order to provide impetus, guidance and support towards improving the quality of organizational processes.

Differential Game-based Formation Flight for Quadrotors

Manuel Jimenez-Lizarraga,Octavio Garcia,Ricardo Chapa-Garcia,Erik G. Rojo-Rodriguez 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.4

This paper focuses on a novel algorithm for the control of formation flight of a set of n-quadrotors based on the differential game approach. The mathematical model of n-quadrotors is presented using the Newton-Euler formulation considering the disturbances, and the formation flight scheme based on the game approach consists of one vehicle acting as a leader following a pre-designed trajectory meanwhile the others vehicles just follow the leader even in the presence of disturbances. A reduced dimension Riccati equation is solved in order to obtain the desired coordination. A numerical example is given in order to illustrate the effectiveness of the approach for the formation flight.

Taxonomic Reassessment of the Genus Padina (Dictyotales, Phaeophyta) from the Gulf of California

Riosmena-Rodriguez, Rafael,Paul-Chavez, Litzia,Hernandez-Carmona, Gustavo,Lopez-Vivas, Juan Manuel,Casas-Valdez, Margarita The Korean Society of Phycology 2009 ALGAE Vol.24 No.4

A monographic reassessment of Padina Adanson species from the Gulf of California was developed based on an exhaustive review of the character and characters states that have been used to delimit species in recent and historically valuable collections. Eight names (P. caulescens Thivy in Taylor, P. concrescens Thivy in Taylor, P. crispata Thivy in Taylor, P. durvillaei Bory Saint-Vincent, P. gymnospora [Kutzing] Sonder, P. mexicana Dawson, P. tetrastromatica Hauck and P. vickersiae Hoyt in Howe) were reported from the region. An analysis of 1,200 specimens led to the conclusion that only three species (P. durvillaei, P. concrescens and P. mexicana) can be recognized for the area based on four discriminating characters: presence of calcium carbonate in the cell wall; number of medullary cell layers in the basal area; number of medullary cell layers in the middle part and presence/absence of cortical cells. Comparative analysis of the species in the Gulf of California in relation to other recently evaluated species has shown a clear distinction among them suggesting Padina species were overestimated in our area.

Taxonomic Reassessment of the Genus Padina (Dictyotales, Phaeophyta) from the Gulf of California

Rafael Riosmena-Rodriguez,Litzia Paul-Chavez,Gustavo Hernández-Carmona,Juan Manuel López-Vivas,Margarita Casas-Valdez 한국조류학회I 2009 ALGAE Vol.24 No.4

A monographic reassessment of Padina Adanson species from the Gulf of California was developed based on an exhaustive review of the character and characters states that have been used to delimit species in recent and historically valuable collections. Eight names (P. caulescens Thivy in Taylor, P. concrescens Thivy in Taylor, P. crispata Thivy in Taylor, P. durvillaei Bory Saint-Vincent, P. gymnospora [Kützing] Sonder, P. mexicana Dawson, P. tetrastromatica Hauck and P. vickersiae Hoyt in Howe) were reported from the region. An analysis of 1,200 specimens led to the conclusion that only three species (P. durvillaei, P. concrescens and P. mexicana) can be recognized for the area based on four discriminating characters: presence of calcium carbonate in the cell wall; number of medullary cell layers in the basal area; number of medullary cell layers in the middle part and presence/absence of cortical cells. Comparative analysis of the species in the Gulf of California in relation to other recently evaluated species has shown a clear distinction among them suggesting Padina species were overestimated in our area.

Biochar-supported nanomaterials for environmental applications

Oscar M. Rodriguez-Narvaez,Juan Manuel Peralta-Hernandez,Ashantha Goonetilleke,Erick R. Bandala 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.78 No.-

Immobilizing nanomaterials in highly porous, surface active, structurally stable biochar creates novelnanocomposites that combines the well-known advantages of both materials. The exceptionalcontaminant adsorption and/or catalytic degradation capabilities of these nanocomposites haveattracted the attention of the scientific community for possible use in environmental applications. Thispaper reviews the different methodologies for synthesizing biochar-supported nanomaterials, the keyphysical and chemical characteristics of these nanomaterials, and their performance in environmentalapplications, as well as identifies current knowledge gaps and potential directions for further researchand development.

Intraoperative pulmonary embolism in shoulder arthroscopy in a patient with previous SARS-CoV-2 infection: a case report

Alejandro Holgado-Rodriguez de,Alberto Izquierdo-Fernandez,Jesus Manuel Mendez-Sanchez,Jose Carlos Diaz-Minarro 대한견주관절의학회 2022 대한견주관절의학회지 Vol.25 No.3

The objective of this article is to describe intraoperative pulmonary embolism during shoulder arthroscopy in a patient with previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Further, we describe how the pandemic has influenced the population by increasing the rate of embolisms. Awareness of such cases will help to increase knowledge regarding SARS-Cov-2 and to determine if such patients should receive routine antithrombotic prophylaxis.

Open Loop Robust Equilibria in Uncertain Discrete Time Games

Fernando Guerrero Vélez,Manuel Jiménez Lizárraga,Celeste Rodriguez Carreon 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.2

This paper tackles the problem of a discrete time N players game affected by some sort of time-varying uncertain perturbation. The philosophy of the uncertainty worst case scenario with respect to the i-player is developed to derive necessary and sufficient conditions for the existence of an Open Loop Robust Nash Equilibria. Such conditions are presented in terms of the solvability of a set of discrete time Riccati type equations with some boundary conditions. As an illustration of the solution, a simulation of the coordination of a two-echelon supply chain with uncertain seasonal fluctuations in the demand is developed.

Morphological reassessment and molecular assessment of Sargassum (Fucales: Phaeophyceae) species from the Gulf of California, Mexico

ANDRADE-SORCIA, GABRIELA,RIOSMENA-RODRIGUEZ, RAFAEL,MUÑ,IZ-SALAZAR, RAQUEL,LÓ,PEZ-VIVAS, JUAN MANUEL,BOO, GA HUN,LEE, KYUNG MIN,BOO, SUNG MIN Magnolia Press 2014 Phytotaxa Vol.183 No.4

<P>Systematic molecular studies have not been performed on ecologically important brown algae (Sargassum) in the Gulf of California, Mexico, where 42 specific and infraspecific names have been recorded within this genus. We conducted phylogenetic analyses of nuclear ribosomal ITS and mitochondrial cox1 and cox3 sequences, along with detailed morphological observations of Sargassum collected in the Gulf of California. We confirmed the presence of six species, five previously described-S. herporhizum, S. horridum, S. johnstonii, S. lapazeanum, and S. sinicola, as well as the newly described Sargassum ulixei sp. nov. which is characterized by terete primary axes arising from the stipe, lanceolate to elliptical sessile ecostate blades with smooth margins, cryptostomata, ellipsoidal vesicles with a short mucron, and cylindrical to ellipsoidal receptacles. The individual analyses and subsequent phylogenetic analysis recognized two groups previously described by Dawson, one as Sargassum and other as Horridum. Our studies suggest that the Gulf of California is a region with endemic Sargassum species, and is clearly distinguished from the Pacific side of Baja California, where recently introduced species are common. Based on phylogenetic relationships, we propose two geographical origins for the Sargassum from the Gulf of California: a first group originating from the proto-Gulf, related to species from the northern hemisphere (including five species); and a second group, containing S. sinicola, introduced when the southern end opened at a later stage. </P>

The erector spinae plane block: a narrative review

Pablo Kot,Pablo Rodriguez,Manuel Granell,Beatriz Cano,Lucas Rovira,Javier Morales,Ana Broseta,Jose De Andrés 대한마취통증의학회 2019 Korean Journal of Anesthesiology Vol.72 No.3

Regional anesthesia and pain management have experienced advances in recent years, especially with the advent of fascial plane blocks. The erector spinae plane block is one of the newest techniques to be described. In the past two years, publications referring to ESP block have increased significantly. The objective of this review is to analyze the articles about ESP block that have been published to date. We performed a search in the main databases and identified 368 articles. After a selection of the relevant articles, 125 studies were found eligible and were included in the review. The ESP block is performed by depositing the local anesthetic in the fascial plane, deeper than the erector spinae muscle at the tip of the transverse process of the vertebra. Many cases of its use have been described with satisfactory results in the treatment of both acute pain and chronic pain. The applicability of the technique covers many clinical scenarios. Of the 98 case reports reviewed, 12 and 87 articles, respectively described the technique as a treatment for chronic pain and acute pain. The single-shot was the most frequently used technique. As described in the articles published to date, the technique is easy to perform and has a low rate of complications. However, despite the effectiveness of the technique, further studies are necessary to obtain more evidence of its actions.