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Diego Hernandez-Hernandez,Tam Larkin,Nawawi Chouw 국제구조공학회 2024 Structural Engineering and Mechanics, An Int'l Jou Vol.89 No.4
This research addresses experimentally the relationship between the excitation frequency and both hoop and axial wall stresses in a water storage tank. A low-density polyethylene tank with six different aspect ratios (water level to tank radius) was tested using a shake table. A laminar box with sand represents a soil site to simulate Soil-Structure Interaction (SSI). Sine excitations with eight frequencies that cover the first free vibration frequency of the tank-water system were applied. Additionally, Ricker wavelet excitations of two different dominant frequencies were considered. The maximum stresses are compared with those using a nonlinear elastic spring-mass model. The results reveal that the coincidence between the excitation frequency and the free-vibration frequency of the soil-tank-water system increases the sloshing intensity and the rigid-like body motion of the system, amplifying the stress development considerably. The relationship between the excitation frequency and wall stresses is nonlinear and depends simultaneously on both sloshing and uplift. In most cases, the maximum stresses using the nonlinear elastic spring-mass model agree with those from the experiments.
Tapia-Hernandez, Alejandro,Ponce-Silva, Mario,Olivares-Peregrino, Victor Hugo,Valdez-Resendiz, Jesus Elias,Hernandez-Gonzalez, Leobardo The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.4
The main contribution of this paper is the use of sensorless active diodes to generate the gate signals for a three-phase boost-rectifier with a self-powered control scheme. The sensorless operation is achieved making use of the gate control signals generated by the active diode schemes on each of the switching devices using a pulse width half-controlled boost rectifier modulation technique (PWM-HCBR). The proposed scheme synchronizes the gate control signals with a three phase voltage supply. Autonomous operation is obtained making use of the output DC bus to feed the control circuitry, the active diodes and the driver circuitry. The three-phase boost-rectifier is supplied by a three-phase permanent magnet electric generator powered by a solar concentrator dish with variable voltage and variable frequency conditions. Experimental results report an efficiency of up to 94.6% for 25 W and an input of 3.6 V peak per phase with 450.
Edgar Hernandez Sosa,Yulianis Martín Castejón,Alexander Batista Duharte,Deivys Portuondo,Vivian Tamayo,Humberto J. Morris Quevedo,Clara Esther Martínez Manrique 한국식품영양과학회 2011 Journal of medicinal food Vol.14 No.9
Trichilia hirta (Family Meliaceae) is a tree traditionally used in the folk medicine of Cuba to treat asthma, cancer, and ulcers. The objective of this study was to determine the phytochemical composition of ethanol extracts obtained from leaves, roots, and stem bark and to evaluate the leukocyte-stimulating effect of T. hirta root extracts on BALB/c mice. The chemical composition of the extracts was determined by phytochemical screening. Saponins, tannins, flavonoids, and coumarins were detected in extracts of T. hirta. The leukocyte-stimulating effect was evaluated by oral application of ethanol extracts (81.8 and 976 mg/kg) in BALB/c mice for 7 days. The application of 976 mg of extract/kg increased the total leukocyte count up to 15–33%; this effect was significant for neutrophil counts compared with control animals (P<.05). In addition, a dose of 82 mg/kg significantly increased total leukocytes at day 4 of the study (P<.05). The results indicated that T. hirta extracts contain phytochemicals reported as immunostimulants. The administration of these extracts to BALB/c mice indicated that ethanol extract could exhibit leukocyte-stimulating properties and makes it a promising alternative for the development of an immunoprotective agent.
Alejandro Tapia-Hernandez,Mario Ponce-Silva,Victor Hugo Olivares-Peregrino,Jesus Elias Valdez-Resendiz,Leobardo Hernandez-Gonzalez 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.4
The main contribution of this paper is the use of sensorless active diodes to generate the gate signals for a three-phase boost-rectifier with a self-powered control scheme. The sensorless operation is achieved making use of the gate control signals generated by the active diode schemes on each of the switching devices using a pulse width half-controlled boost rectifier modulation technique (PWM-HCBR). The proposed scheme synchronizes the gate control signals with a three phase voltage supply. Autonomous operation is obtained making use of the output DC bus to feed the control circuitry, the active diodes and the driver circuitry. The three-phase boost-rectifier is supplied by a three-phase permanent magnet electric generator powered by a solar concentrator dish with variable voltage and variable frequency conditions. Experimental results report an efficiency of up to 94.6% for 25 W and an input of 3.6 V peak per phase with 450.
Vitamin D and its effects on cardiovascular diseases: a comprehensive review
( Nonanzit Perez-hernandez ),( Gad Aptilon-duque ),( Maria Cristina Nostroza-hernandez ),( Gilberto Vargas-alarcon ),( Jose Manuel Rodriguez-perez ),( Ruben Blachman-braun ) 대한내과학회 2016 The Korean Journal of Internal Medicine Vol.31 No.6
Vitamin D is a molecule that is actively involved in multiple metabolic pathways. It is mostly known for its implications related to calcium metabolism. It has also been determined that it actively participates in the cardiovascular system, influencing blood pressure, coronary artery disease and other vascular diseases, such as heart failure and atrial fibrillation. Furthermore, it has been established that this vitamin is extensively involved in the regulation of both the renin angiotensin aldosterone system and the immune system. In this review, we present the different vitamin D metabolic pathways associated with the cardiovascular pathophysiology, and we include studies in animal and human models, as well as some of the controversies found in the literature. This review also incorporates an overview of the implications in the molecular biology and public health fields.
Computing the Refined Compression Field Theory
Hernandez-Diaz, A.M.,Garcia-Roman, M.D. Korea Concrete Institute 2016 International Journal of Concrete Structures and M Vol.10 No.2
In recent years, some modifications were introduced in the stress-strain relationship of the steel in order to develop a more efficient shear model for reinforced concrete members. The last contribution in this sense corresponding to the Refined Compression Field Theory (RCFT, 2009); this theory proposed a steel constitutive model that has account the tension stiffening area prescribed by technical codes, what simplifies all the design process. However, under certain design conditions supported by such codes, the RCFT model does not provide a real (non-complex) solution for the steel yield strain when the prescribed tension stiffening area is considered; then the load-strain response cannot be computed. In this technical note, the tension stiffening area is fixed in order to guarantee the application of the embedded steel constitutive model for all the standard design range.
Hernandez-Ortiz, Juan P.,Ma, Hong-Bo,de Pablo, Juan J.,Graham, Michael D. The Korean Society of Rheology 2008 Korea-Australia rheology journal Vol.20 No.3
Simulations of solutions of flexible polymer molecules during flow in simple or complex confined geometries are performed. Concentrations from ultradilute up to near the overlap concentration are considered. As concentration increases, the hydrodynamic migration effects observed in dilute solution unidirectional flows (Couette flow, Poiseuille flow) become less prominent, virtually vanishing as the overlap concentration is approached. In a grooved channel geometry, the groove is almost completely depleted of polymer chains at high Weissenberg number in the dilute limit, but at finite concentration this depletion effect is dramatically reduced. Only upon inclusion of hydrodynamic interactions can these phenomena be properly captured.
Public Diplomacy, Soft Power and Language: The Case of the Korean Language in Mexico City
Hernandez, Eduardo Luciano Tadeo World Association for Triple Helix and Future Stra 2018 Journal of Contemporary Eastern Asia Vol.17 No.1
Public Diplomacy (PD) is the third pillar of South Korean foreign policy. According to the Ministry of Foreign Affairs, PD aims to attract foreign audiences by means of art, knowledge transmission, media, language and foreign aid. When it comes to the Korean language, its global profile has seen an especially marked increase in recent years (Kim, 2009). Thus, this paper's objective is to explain the relevance of the Korean language in the generation of South Korea's soft power. I draw from $C{\acute{e}}sar$ Villanueva's reflections in order to problematize how language promotion can be translated into soft power at five different levels: the empathetic, the sympathetic, the geopolitical, the diplomatic and the utilitarian. I observe that in the case of the Korean language in Mexico City, soft power has the potential to be generated on three levels: it helps to increase knowledge of Korean culture (empathetic); it exercises symbolic persuasion (geopolitical), since the products of cultural industries are mostly in Korean; and it is used as a tool for economic transactions in Mexico City (utilitarian).