423 research outputs found
A stochastic multiaxial fatigue model for off-axis cracking in FRP laminates
No full textA model to predict off-axis crack evolution in multidirectional laminates subjected to multiaxial loading is proposed. The model applies multi-scale stress and local fracture mechanics analyses to distinguish between two microscopic damage mechanisms, which govern the damage evolution, as well as determining the magnitude of the damage evolution rate associated with each microscopic damage mechanism. The multi-scale analysis is based on the GLOB-LOC off-axis crack damage model, which is extended to include substantial new capabilities such as the influence of crack face sliding interaction and prediction of variations in the stress field due to the local crack density. The extension of the GLOB-LOC model introduces physically based multiaxial fatigue criteria for off-axis crack initiation and mixed-mode off-axis crack propagation. The extended GLOB-LOC model is implemented and it is demonstrated that good predictions are obtained for the damage evolution under various multiaxial stress conditions. Furthermore it is shown that the model only requires input from two different multiaxial stress states to obtain the material parameters for a given FRP ply.</p
Frost formation: The influence of frost formation and defrosting on the performance of air coolers
No full textMechanical, Maritime and Materials Engineerin
A damage-based model for mixed-mode crack propagation in composite laminates
No full textA model for the off-axis crack propagation in laminated fibre reinforced polymer composites subjected to multiaxial fatigue loadings is presented. On the basis of several observations reported in the literature, the crack propagation phenomenon can be seen as the result of a series of micro-scale events occurring ahead of the crack tip within a process zone. The mixed mode loading condition defines the type of the micro-scale events which occur in the process zone and lead to fatigue crack propagation. Based on this evidence and by using a multiscale approach to determine the micro-scale stress fields in the matrix, two simple parameters are defined for predicting the crack growth rate through a Paris-like law. By extracting the proposed parameters from experimental data obtained from the literature, it is demonstrated that the crack propagation data are all included into two Paris-like scatter bands covering the whole mode-mixity range
Micromanufacturing of Conductive Polymer Electrodes for Sensing Microsystems
No full textWearable technologies are receiving a growing attention from research and industry in many different scientific areas [1]. Many of the commercialized devices are mainly based on the detection of gravitational, electric or acoustic impulse and environmental sensors [2]. However, for various healthcare applications it is of vital importance to be able to analyse bodily fluids, detecting microscopic biomarkers in order to monitor health conditions in a continuous, not-invasive and localized way. For this reason, the realization of the realization of in-situ wearable electrochemical bio-sensors is highly needed since it will open the possibility of mass screening and personalized medicine [1]. Conductive polymers are well suited for wearable bio-sensor applications, due to their unique electrical and optical properties that can be selected by choosing among a broad range of available materials [3][4][5]. Moreover, they provide also biocompatibility, low cost and easy manufacturability. This thesis presents a low cost and simple method for fabricating an all polymeric device for pH monitoring. Indeed, pH is one of the keys indicator of wound infection and it is important to study its evaluation during wound healing in order to select the right therapy. The device consists of a microfluidic channel, for uid handling, and polymeric electrodes made of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), one of the most promising conductive electrodes. The PEDOT layer has been created by spin-coating on a cyclic ole_n copolymer (COC) substrate and has been characterized by both contact and optical interferometry. In order to increase adhesion, isopropanol has been added to PEDOT before spin-coating and a post-process treatment with ethylene glycol has demonstrated to be crucial to increase the PEDOT conductivity and decrease its solubility in water, Electrodes coupled with microchannels were fabricated by mean of a single hot embossing process. The thesis presents a comparison between a standard hot embossing process with a soft embossing one (in which the mold is polymeric). Two different processes for fabrication the mold are discussed: direct milling of aluminum for the hard mold and soft lithography with polydimethilsiloxane on a polystyrene master. The polymeric electrodes obtained after embossing have been characterized by means of electrical and electrochemical measurements. In order to impart pH sensitivity, a pH sensitive layer of polyaniline has been electropolimerized on the PEDOT working electrode and characterized by means of SEM imaging and electrochemistry. Finally, the response of the device to a relevant range of pH is tested and validated by monitoring its potentiometric response. In conclusion, this thesis describes the development and characterization of an all polymeric microfluidic pH sensing system with integrated electrodes manufactured by means of a single-step embossing process.Mechanical, Maritime and Materials EngineeringPrecision and Microsystems Engineerin
The Negotiated Approach to River Basin Management - An analysis of the approach, its uniqueness and its future
No full textTechnology, Policy and Managemen
Point-of-Care Diagnostic Test for Rapid Detection of Infectious Laryngotracheitis Virus by Loop-Mediated Isothermal Amplification and Nanoprobes
No full textAuthor Contributions:
Conceptualization, P.C.-C., R.M. and L.B.; formal analysis, P.C.-C., C.T. and R.M.; investigation, P.C.-C., C.T., E.E.M., M.B., J.M.C. and C.J.S.-L.; methodology P.C.-C., R.M. and L.B.; writing—original draft, P.C.-C., A.D., R.M. and L.B.; writing—review and editing, P.C.-C., C.T., E.G.-L., A.D., R.M. and L.B.; resources, E.G.-L., A.D., M.B. and J.M.C.; funding and acquisition, A.D. and L.B.; supervision, A.D., R.M. and L.B.; project administration, R.M. and L.B. All authors have read and agreed to the published version of the manuscript.Infectious laryngotracheitis virus (ILTV), a DNA virus classified as Gallid alphaherpesvirus 1, causes a highly contagious respiratory disease in chickens, leading to significant economic losses and health risks for the poultry industry. The rapid detection of ILTV is essential to control its spread and prevent outbreaks. Traditional diagnostic methods like PCR are costly, require specialized personnel, and delay response efforts. To address this, we developed a point-of-care diagnostic test combining loop-mediated isothermal amplification (LAMP) with DNA nanoprobes on respiratory swabs. LAMP targets the ILTV-glycoprotein E (gE) gene, enabling rapid nucleic acid amplification at 65 °C without extraction, making it suitable for on-site detection. DNA nanoprobes provide a colorimetric readout visible to the naked eye. Gold nanoparticles drive this readout, as their red color, based on localized surface plasmon resonance, persists in the presence of ILTV DNA through DNA-DNA hybridization, ensuring reliable detection. The assay achieved 100% sensitivity and specificity for ILTV-gE, with a detection limit of 200 copies per reaction, allowing for the early identification of infections. The results are available within 45 min, enabling prompt measures to control ILTV spread. Cost-effective and user-friendly, this method enhances disease management and biosecurity in poultry farms.Ministerio de Ciencia, Innovación y Universidades (España)Comunidad de MadridDepto. de Sanidad AnimalDepto. de Genética, Fisiología y MicrobiologíaDepto. de Química FísicaFac. de VeterinariaFac. de Ciencias BiológicasFac. de Ciencias QuímicasTRUEpu
Etude de la relation existant, chez Aedes aegypti L., entre la durée d'exposition à un insecticide et la mortalité résultante [Dipt. Nematocera]
No full textUsing the W.H.O. test kit for adult mosquitoes, the author studies the exposure period-mortality relationship.
Young unfed females of Ae. aegypti and W.H.O. dieldrin and malathion impregnated papers are used, with exposure periods of 7m. 30s. up to 8 hours.
The recorded mortality is proportional to the exposure period logarithm. Characteristic lethal concentrations are inversely proportional to exposure period along the equation c.t = K.
So insecticide susceptibility in adult mosquitoes, Phlebotomus, tsetse flies, Stomoxys and Drosophila can be expressed either by characteristic lethal concentration, or by characteristic lethal exposure period.L'auteur étudie, à l'aide de la trousse O.M.S. pour la détermination de la sensibilité aux insecticides des moustiques adultes, la relation existant entre la durée d'exposition à l'insecticide et la mortalité.
Il utilise des femelles jeunes à jeun d'Ae. aegypti et les papiers O.M.S. imprégnés de dieldrine et de malathion, avec des temps d'exposition allant de 7m 30s à 8 heures.
La mortalité observée est proportionnelle au logarithme de la durée d'exposition. Les concentrations létales caractéristiques sont inversement proportionnelles au temps d'exposition selon une fonction du type c.t = constante.
Pour les moustiques adultes, les phlébotomes, les glossines, les stomoxes et les drosophiles, la sensibilité aux insecticides peut donc aussi bien être exprimée sous forme de temps d'exposition létal que sous forme de concentration létale.Hamon J. Etude de la relation existant, chez Aedes aegypti L., entre la durée d'exposition à un insecticide et la mortalité résultante [Dipt. Nematocera]. In: Bulletin de la Société entomologique de France, volume 68 (9-10), Novembre-décembre 1963. pp. 225-232
Etude de la relation existant, chez Aedes aegypti L., entre la durée d'exposition à un insecticide et la mortalité résultante [Dipt. Nematocera]
No full textUsing the W.H.O. test kit for adult mosquitoes, the author studies the exposure period-mortality relationship.
Young unfed females of Ae. aegypti and W.H.O. dieldrin and malathion impregnated papers are used, with exposure periods of 7m. 30s. up to 8 hours.
The recorded mortality is proportional to the exposure period logarithm. Characteristic lethal concentrations are inversely proportional to exposure period along the equation c.t = K.
So insecticide susceptibility in adult mosquitoes, Phlebotomus, tsetse flies, Stomoxys and Drosophila can be expressed either by characteristic lethal concentration, or by characteristic lethal exposure period.L'auteur étudie, à l'aide de la trousse O.M.S. pour la détermination de la sensibilité aux insecticides des moustiques adultes, la relation existant entre la durée d'exposition à l'insecticide et la mortalité.
Il utilise des femelles jeunes à jeun d'Ae. aegypti et les papiers O.M.S. imprégnés de dieldrine et de malathion, avec des temps d'exposition allant de 7m 30s à 8 heures.
La mortalité observée est proportionnelle au logarithme de la durée d'exposition. Les concentrations létales caractéristiques sont inversement proportionnelles au temps d'exposition selon une fonction du type c.t = constante.
Pour les moustiques adultes, les phlébotomes, les glossines, les stomoxes et les drosophiles, la sensibilité aux insecticides peut donc aussi bien être exprimée sous forme de temps d'exposition létal que sous forme de concentration létale.Hamon J. Etude de la relation existant, chez Aedes aegypti L., entre la durée d'exposition à un insecticide et la mortalité résultante [Dipt. Nematocera]. In: Bulletin de la Société entomologique de France, volume 68 (9-10), Novembre-décembre 1963. pp. 225-232
Multiphysics simulation explaining the behaviour of evaporation-driven nanoporous generators
No full textFunding Information: The authors acknowledge the financial support from the Academy of Finland project 319018. L.H. and T.K. acknowledge funding from the Aalto ELEC doctoral school, and C.T. from the Vilho, Yrjö ja Kalle Väisälä Fund grant issued by the Finnish Academy of Arts and Sciences. T.K. acknowledges the support from the Walter Ahlström foundation. Further thanks go to Dr. Benjamin Wilson for the pycnometry measurements. The pycnometry was done using the Raw Materials research infrastructure by Aalto University School of Chemical Engineering, and other experimental work using the facilities and equipment of Micronova Nanofabrication Center. Finally, we acknowledge the computational resources provided by the Aalto Science-IT project. Funding Information: The authors acknowledge the financial support from the Academy of Finland project 319018. L.H. and T.K. acknowledge funding from the Aalto ELEC doctoral school, and C.T. from the Vilho, Yrj? ja Kalle V?is?l? Fund grant issued by the Finnish Academy of Arts and Sciences. T.K. acknowledges the support from the Walter Ahlstr?m foundation. Further thanks go to Dr. Benjamin Wilson for the pycnometry measurements. The pycnometry was done using the Raw Materials research infrastructure by Aalto University School of Chemical Engineering, and other experimental work using the facilities and equipment of Micronova Nanofabrication Center. Finally, we acknowledge the computational resources provided by the Aalto Science-IT project. Publisher Copyright: © 2022 The Author(s)Evaporation-induced electricity generation in porous nanomaterials has recently attracted considerable attention due to relatively high produced voltages and wide operating conditions. Here, we present a combined study of computational and experimental work exploiting finite-element method simulations to find the critical parameters influencing the performance of such generators. The simulated behaviour is found to agree with the experimental data within typical variation of the measurements. We find that the electrical power produced by the generator depends not only on the properties of the porous material, but also on the surrounding environment of the generator. Particularly, the pore size and geometry are found to have a significant influence on the output power, highlighting the importance of accurate characterization of the samples and careful control of the laboratory conditions when performing experimental work. Increasing the pore size from 5 to 20 nm improves the simulated output voltage from 0.12 to 0.47 V, while increasing the ambient humidity to 100% will prevent voltage generation completely. The obtained results can guide the future design of generators based on water evaporation induced capillary flow in a nanoporous carbon black film, leading to more efficient power production.Peer reviewe
How does Zinfluence Affect Article Influence?
No full textFor financial support, the first author acknowledges the National Science Council, Taiwan; the second author acknowledges the Australian Research Council, National Science Council, Taiwan, a Visiting Erskine Fellowship, College of Business and Economics, University of Canterbury, and the Japan Society for the Promotion of Science; and the third author acknowledges the Royal Society of New Zealand, Marsden Fund.IFI;PI-BETA;STAR;article influence;eigenfactor;h-index;immediacy;impact factors;zinfluence;C3PO;cited article influence
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