Experimental deployment and validation of a distributed SHM system using wireless sensor networks

Nestor E. Castaneda,Shirley Dyke,Chenyang Lu,Fei Sun,Greg Hackmann 국제구조공학회 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.32 No.6

Recent interest in the use of wireless sensor networks for structural health monitoring (SHM) is mainly due to their low implementation costs and potential to measure the responses of a structure at unprecedented spatial resolution. Approaches capable of detecting damage using distributed processing must be developed in parallel with this technology to significantly reduce the power consumption and communication bandwidth requirements of the sensor platforms. In this investigation, a damage detection system based on a distributed processing approach is proposed and experimentally validated using a wireless sensor network deployed on two laboratory structures. In this distributed approach, on-board processing capabilities of the wireless sensor are exploited to significantly reduce the communication load and power consumption. The Damage Location Assurance Criterion (DLAC) is used for localizing damage. Processing of the raw data is conducted at the sensor level, and a reduced data set is transmitted to the base station for decision-making. The results indicate that this distributed implementation can be used to successfully detect and localize regions of damage in a structure. To further support the experimental results obtained, the capabilities of the proposed system were tested through a series of numerical simulations with an expanded set of damage scenarios.

Copper- and Zinc-Enriched Mycelium of Agaricus blazei Murrill: Bioaccumulation and Bioavailability

Nestor Curvetto,Maia Rabinovich,Debora Figlas,Silvia Delmastro 한국식품영양과학회 2007 Journal of medicinal food Vol.10 No.1

Agaricus blazeiis an edible mushroom with medicinal properties. To obtain organic combinations of poten-tial utility as a food dietary supplement, the accumulation and potential bioavailability of copper (Cu) and zinc (Zn) onmycelium grown in the presence of these metals were studied. At 400 ppm, the mycelium accumulated 449 and 163 timesthe basal content of Cu and Zn, respectively. When mycelia cultivated with nonmycotoxic concentrations of Cu or Zn (100and 200 ppm) were subjected to sequential chemical extraction and simulated gastrointestinal digestion, close to 90% of themetals accumulated in the available nonresidual fraction, which was similar to or better than the values found in two com-mercial supplements. The solubility in the simulated digestive fluids was 3034% and 1833%, i.e., 6098% and 911% ofthe recommended daily intake for Cu and Zn, respectively, with only 1 g of mycelium.

Primate cities in Latin America: a theoretical framework based upon intra-urban driving forces

Nestor Garza 서울시립대학교 도시과학연구원 2016 도시과학국제저널 Vol.20 No.3

Excessive urban primacy in Latin American countries has been primarily analysed using country-level perspectives, while their intra-urban spatial forces have not been routinely used as explanatory elements. This paper addresses this gap by relating two country-level sources of urban primacy (the international economic dependence of Latin American countries and the rural bias of the political process), with three particularities of the Latin American spatial markets (lack of land taxes and exactions, informal mechanisms of access to land, and lobby-oriented oligopolistic formal developers). We develop graphic analytical frameworks where we can hypothesize the interactions between all these elements. In order to enhance the theoretical framework and contrast it with existing evidence, three emerging policies in the continent were added to the analysis: land taxation and exactions, tenure legalization, and global city development. By using the theoretical framework, we conclude that the combined effects of these emerging policies will determine primacy patterns similar to the ones currently prevailing.

Industry Definition and Less Than Fair Value Pricing: an Analysis of ITC Practice

( Nestor M. Arguea ),( Richard K. Harper ) 세종대학교 경제통합연구소 1994 Journal of Economic Integration Vol.9 No.1

In reaching an injury determination in U.S. antidumping and antisubsidy cases, the potentially injured domestic industry and thus scope of an investigation must be defined. However, a systematic process of market definition has yet to evolve in ITC decision making, leaving the question to instead be considered on a case by case basis. Cluster analysis of commuter aircraft cases suggests that current ITC practice may often lead to a definition of domestic industry which is too narrow.

Theoretical model to determine bond loss in prestressed concrete with reinforcement corrosion

Ortega, Nestor F.,Moro, Juan M.,Meneses, Romina S. Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.65 No.1

This paper reviews the mechanical effects produced by reinforcement corrosion of prestressed concrete beams. Specifically, modifications in the bonding of the tendon to the concrete that reduce service life and load bearing capacity are studied. Experimental information gathered from previous works has been used for the theoretical analysis. Relationships between bond stress loss and reinforcement penetration in the concrete, and concrete external cracking were established. Also, it was analysed the influence that has the location of the area affected by corrosion on the loss magnitude of the initial prestress.

A taxonomic and distributional study of the rhodolith-forming species Lithothamnion muelleri (Corallinales, Rhodophyta) in the Eastern Pacific Ocean

Robinson, Nestor M.,Hansen, G.I.,Fernandez-Garcia, C.,Riosmena-Rodriguez, R. The Korean Society of Phycology 2013 ALGAE Vol.28 No.1

Lithothamnion muelleri is reported for the first time as one of the main components of rhodolith beds along the Eastern Pacific Ocean based on samples from Washington State (USA), Pacific Baja California (M$\acute{e}$xico), southern Nicaragua, and Costa Rica. Individual rhodoliths ranged from fruticose to lumpy in morphology, and bi-sporangial, tetrasporangial, and gametangial plants were similar to those described from Australia and Brazil. Our study revealed a surprisingly wide latitudinal distribution of this species along the American continent. Its documentation in the Eastern Pacific will facilitate a more accurate interpretation of the ecology, biology, and biogeography of rhodolith beds worldwide.

Experimental deployment and validation of a distributed SHM system using wireless sensor networks

Castaneda, Nestor E.,Dyke, Shirley,Lu, Chenyang,Sun, Fei,Hackmann, Greg Techno-Press 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.32 No.6

Recent interest in the use of wireless sensor networks for structural health monitoring (SHM) is mainly due to their low implementation costs and potential to measure the responses of a structure at unprecedented spatial resolution. Approaches capable of detecting damage using distributed processing must be developed in parallel with this technology to significantly reduce the power consumption and communication bandwidth requirements of the sensor platforms. In this investigation, a damage detection system based on a distributed processing approach is proposed and experimentally validated using a wireless sensor network deployed on two laboratory structures. In this distributed approach, on-board processing capabilities of the wireless sensor are exploited to significantly reduce the communication load and power consumption. The Damage Location Assurance Criterion (DLAC) is used for localizing damage. Processing of the raw data is conducted at the sensor level, and a reduced data set is transmitted to the base station for decision-making. The results indicate that this distributed implementation can be used to successfully detect and localize regions of damage in a structure. To further support the experimental results obtained, the capabilities of the proposed system were tested through a series of numerical simulations with an expanded set of damage scenarios.

Industry Definition and Less Than Fair Value Pricing : an Analysis of ITC Practice

Arguea, Nestor M.,Harper, Richard K. 세종대학교 국제경제연구소 1994 Journal of Economic Integration Vol.9 No.1

In reaching an injury determination in U.S. antidumping and antisubsidy cases, the potentially injured domestic industry and thus scope of an investigation must be defined. However, a systematic process of market definition has yet to evolve in ITC decision making, leaving the question to instead be considered on a case by case basis. Cluster analysis of commuter aircraft cases suggests that current ITC practice may often lead to a definition of domestic industry which is too narrow.

Optimization of a telescope movable support structure by means of Volumetric Displacements

Ortega, Nestor F.,Robles, Sandra I. Techno-Press 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.31 No.4

The Purpose of this paper is to show the applicability of a methodology, developed by the authors, with which to perform the mechanical optimization of space truss structures strongly restricted. This methodology use a parameter call "Volumetric Displacement", as the Objective Function of the optimization process. This parameter considers altogether the structure weight and deformation whose effects are opposed. The Finite Element Method is employed to calculate the stress/strain state and the natural frequency of the structure through a structural linear static and natural frequency analysis. In order to show the potentially of this simple methodology, its application on a large diameter telescope structure (10 m) considering the strongly restriction that became of its use, is presented. This methodology, applied in previous works on continuous structures, such as shell roof and fluid storage vessels, is applied in this case to a space truss structure, with the purpose of generalize its applicability to different structural topology. This technique could be useful in the morphology design of deployable and retractable roof structures, whose use has extensively spread in the last years.

Beams affected by corrosion influence of reinforcement placement in the cracking

Ortega, Nestor F.,Rivas, Irene E.,Aveldano, Raquel R.,Peralta, Maria H. Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.37 No.2

The results of experimental and numerical investigations on reinforced concrete beams, with different longitudinal rebars affected by corrosive processes are presented in this paper. Different diameters and/or different distributions of longitudinal rebars were employed keeping constant the total section in each analyzed case, (maintaining a constant stirrup diameter and distribution). The rebars were subjected to accelerated corrosion in the experimental study. Electrochemical monitoring of the process, periodic measuring of the cover cracking and gravimetry of the rebars were performed through the test. Some building recommendations are obtained in order to be considered by designers of concrete structures. The numerical simulation was carried out through the application of the Finite Element Method (FEM), employing plane models, and using linear-elastic material model. The cracking process was associated with the evolution of the tensile stresses that were originated. This numerical methodology allows the monitoring of the mechanical behavior until the beginning of the cracking.