Effect of Load on Machine Geometry with Respect to the Weight and Torque

RÉSUMÉ Dans cette étude, une méthode est développée pour estimer et prédire les coefficients d'erreur de la déformation d‟une machine CNC à cinq axes sous différentes conditions de chargement. Pour étudier l'effet de différents poids et les couples sur les erreurs de la machine, les blocs lourds identiques (10 kg chacun) ainsi que des entretoises lumière ont été conçus et fabriqués. Après installer les bocs et les boules sur la palette, la machine sonde les boules pour différents angles indexés par rapport à ses deux axes de rotation (B et C axes) en utilisant les codes G générés par programme RUMBA (the 3D reconfigurable uncalibrated master balls artifact). Au total, il y a 26 types d'erreurs et chaque erreur a maximum de cinq coefficients qui sont appelés coefficients d'erreur estimés. Les données obtenues à partir de la machine sont traitées afin d'estimer les valeurs des coefficients d'erreur pour chaque erreur. Ces derniers permettent d'obtenir les graphiques polynômes de chaque erreur en utilisant leurs coefficients d'erreur. En outre, la matrice de corrélation de Pearson est obtenue pour tous les coefficients d'erreur et des poids et des couples. Les éléments de la matrice de corrélation (entre -1 et 1) indiquent le degré de dépendance de chaque coefficient d'erreur pour les autres coefficients, ainsi que le poids et le couple. Enfin, le procédé d'ajustement de la courbe est utilisé pour modéliser chaque coefficient d'erreur en fonction du poids et du couple. Ceci permet de prédire la valeur du coefficient d'erreur pour toutes les valeurs de poids et de couple supprimant la nécessité l'essai expérimental. L'analyse résiduelle (la différence entre les valeurs expérimentales et les valeurs prédites) est ensuite utilisée pour vérifier l'exactitude du modèle. Les résultats de cette étude montrent que cette méthode est suffisamment précise pour estimer les erreurs de la machines qui est testés (HU40T machine CNC à cinq axes). Le modèle nous permet d'estimer les valeurs des coefficients d'erreur en fonction du poids uniquement, en fonction du couple uniquement et en fonction du poids et du couple simultanément. Cette connaissance est importante pour la compensation d'erreur ou la suppression d'erreur dans la machine pour augmenter la précision de la fabrication.----------ABSTRACT In this study, a method is developed to estimate and predict the error coefficients of a five-axis CNC machine tool deformation under different loading conditions. To study the effect of different weights and torques on the machine errors, identical heavy blocks (10 Kilograms each) as well as light spacers (less than 1 Kilogram) are designed and fabricated. After assembling the blocks and master balls on the pallet, the machine probes the balls for different indexations from the rotary axes (B and C axes) of the machine using G-codes generated from the 3D reconfigurable uncalibrated master balls artefact (RUMBA) program. In total, there are 26 types of errors and each error has maximum five coefficients which are called estimated error coefficients. The raw data obtained from machine is processed to estimate the values of the error coefficients for each error. Then, the polynomial function of each error can be achieved by using their error coefficients. Furthermore, Pearson‟s correlation matrix is obtained for all error coefficients and weights and torques. The elements of the correlation matrix (between -1 and 1) show the extent of dependency of each error coefficient to other coefficients as well as to the weight and torque. Finally, the curve fitting method is used to model each error coefficient as a function of weight and torque. The modeling allows predicting the value of the error coefficient for any weights and torques without doing an experimental test. Residual analysis (difference between the experimental and the predicted values) is then used to verify the accuracy of the modeling. The results of this study show that this method is accurate enough to estimate the errors of the tested machine tool (HU40T 5-axis CNC machine tools). The model enables us to estimate the error coefficient values as a function of weight independently, torque independently and weight and torque simultaneously. This knowledge is important for error compensation or even error removal in machine to increase the precision of the manufacturing

Detection of Nicotine Effect on Colon Cells in a Plasmonic Platform

Introduction: Smoking as one of the causes of various diseases has encouraged worldwide studies on its adverse pharmacological effects on different organs. Nicotine may influence the smooth muscles of the colon and subsequently the gut motility, which leads to a change in the moving rate of digested material through the gastrointestinal tract.Methods: Among various techniques, optical detection methods benefit from non-contact and high-sensitivity for studying the early effect of nicotine on the cells. Thus, we used an optically ellipsometric method to get the fast and sensitive nicotine effect on the colon cell. Two-dimensional plasmonic platforms by gold deposition onto the polydimethylsiloxane polymer (PDMS) patterned substrate were used as the guest medium of the cell and the sample was excited by all of the visible region wavelengths at different exposure time and maintenance time.Results: Our results showed that the phase difference between each polarization increased by augmenting the exposure time of smoke over the cell at a fixed maintenance time and there was a general red-shift by increasing the maintenance time at a fixed exposure time.Conclusion: Using different exposure time to cigarette smoke, we optically showed that the cigarette containing the addicting chemical of nicotine had a direct effect on the cultured colon cells on our 2D biocompatible plasmonic chip. It demonstrated considerable changes in the amplitude and phase of the interacted light by injecting nicotine into the system with the aid of the label-free and non-invasive plasmonic technique

Optical Fiber Biosensor toward E-coli Bacterial Detection on the Pollutant Water

In this study, Zinc oxide (ZnO) nanorods based fiber optic biosensor has been reported for rapid and sensitive detection of Escherichia Coli (E-coli). A thin layer of Gold nanoparticles (Au) (around 50 nm) is coated on the tip of a multimode plastic optical fiber.  ZnO Nanorods are grown on Au layer thorough hydrothermal technique. This sensor showed a very fast response within the first 10 second of contacting the present of polluted water with E-coli Different concentrations of E. coli from (1000 to 4000 CFU/ml) have been tested and a sharp trend of sensitivity was observed. This sensing platform shows promising potential for regular water and food quality monitoring of various pathogenic microorganisms

Upconversion Nanomaterials: Synthesis, Mechanism, and Applications in Sensing

Upconversion is an optical process that involves the conversion of lower-energy photons into higher-energy photons. It has been extensively studied since mid-1960s and widely applied in optical devices. Over the past decade, high-quality rare earth-doped upconversion nanoparticles have been successfully synthesized with the rapid development of nanotechnology and are becoming more prominent in biological sciences. The synthesis methods are usually phase-based processes, such as thermal decomposition, hydrothermal reaction, and ionic liquids-based synthesis. The main difference between upconversion nanoparticles and other nanomaterials is that they can emit visible light under near infrared irradiation. The near infrared irradiation leads to low autofluorescence, less scattering and absorption, and deep penetration in biological samples. In this review, the synthesis of upconversion nanoparticles and the mechanisms of upconversion process will be discussed, followed by their applications in different areas, especially in the biological field for biosensing

Transport and survival of bacteria in model aquatic environments: role of water chemistry, surface geochemistry, and temperature

The occurrence of microbial pathogens in drinking water sources is recognized as a significant threat to public health. A better understanding of the key processes governing the fate of microbial pathogens in groundwater aquifers can help mitigate the risk of drinking water contamination. The attachment of pathogens to aquifer surfaces and the inactivation of attached and suspended pathogens are key processes that attenuate the concentration of viable pathogens in potable water supplies. Although substantial research effort has been aimed at elucidating the role of various physical, chemical and biological factors on the inactivation rate of microbes suspended in the aqueous phase, our understanding of microbe inactivation when attached to grain surfaces is limited. Thus, the first objective of this work was to develop a fluorescence-based experimental technique for evaluating the inactivation kinetics of bacteria adhered onto a surface in an aqueous environment. The technique was sensitive enough to distinguish between the inactivation kinetics of different representative bacteria attached to either a negatively or a positively charged surface. The new method was then used to characterize bacterial inactivation kinetics when attached to environmentally relevant surface chemistries such as metal oxides over a broad range of groundwater chemistries. X-ray photoelectron spectroscopy (XPS) characterization of bacterial-surface bonding was used to interpret inactivation behavior. It was observed that attachment of cells to metal-oxide surfaces can lead to formation of covalent bonds, specifically O- and C-metal bonds, between the cell and the surface, resulting in reduced bacterial viability (i.e., cell membrane integrity). Surface and near-surface soils in cold climate regions experience low temperature and freeze-thaw (FT) conditions in the winter. Microorganisms that are of concern to groundwater quality may have the potential to survive low temperature and FT in the soil and aqueous environments. Although there is a large body of literature on the survival of pathogenic bacteria at different environmental conditions, little is known about their transport in groundwater environments in low temperatures and after FT. Thus, in the second part of the project, the effect of cold temperature and repeated FT on survival, survival strategies such as motility and biofilm formation, and virulence of selected Gram-negative and Gram-positive bacteria was investigated. The adhesion properties and transport of bacteria exposed to FT were studied using quartz crystal microbalance with dissipation monitoring (QCM-D) and water saturated sand-packed columns. The expression levels of different genes encoding synthesis of flagellin, extracellular matrix production, and virulence factors were measured using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Our findings demonstrate that bacteria exhibited greater retention onto sand grains after exposure to FT. Moreover, bacteria tend to survive for longer periods of time and may become more virulent at low temperature in higher ionic strength waters thereby posing a potential threat to drinking water supplies.L'apparition d'agents pathogènes microbiens dans les sources d'eau potable est reconnu comme une menace importante pour la santé publique. Une meilleure compréhension des processus fondamentaux qui régissent le sort des pathogènes microbiens dans les aquifères d'eau souterraine peut contribuer à atténuer le risque de contamination de l'eau potable. L'attachement des agents pathogènes aux surfaces des nappes phréatiques et leur inactivation lorsqu'ils sont attachés et suspendus, sont les processus clés qui atténuent la concentration des pathogènes viables dans l'approvisionnement en eau potable. Bien qu'un effort substantiel de recherche ait été réalisé, visant à élucider le rôle de divers facteurs physiques, chimiques et biologiques sur le taux d'inactivation des microbes en suspension dans la phase aqueuse, notre compréhension de l'inactivation du microbe lorsqu'il est attaché à la surface des grains est limitée. Ainsi, le premier objectif de ce travail était de développer une technique expérimentale basée sur la fluorescence pour évaluer la cinétique d'inactivation de bactéries collées sur une surface dans un environnement aqueux. La technique est suffisamment sensible pour faire la distinction entre la cinétique d'inactivation de différentes bactéries représentatives, montées soit sur une surface chargée négativement ou positivement. La nouvelle méthode a ensuite été utilisée pour caractériser la cinétique d'inactivation bactérienne lorsqu'elle est reliée à la chimie de surface environnementale telle que les oxydes métalliques et ceci sur une large gamme de produits chimiques des eaux souterraines. La caractérisation de la liaison bactérienne de surface par spectroscopie photoélectronique X (XPS) a été utilisée pour interpréter le comportement de l'inactivation. Il a été observé que l'attachement des cellules aux surfaces métal-oxyde peut conduire à la formation de liaisons covalentes, plus précisément des liaisons O- et C-métal, entre la cellule et la surface, ce qui entraîne une réduction de la viabilité bactérienne (i.e. une perte de l'intégrité de la membrane cellulaire).Dans les régions à climat froid, les sols de surface ou proches de la surface subissent de basses températures et des périodes de gel-dégel (GD). Les micro-organismes qui sont des sources de préoccupation pour la qualité des eaux souterraines peuvent avoir le potentiel de survivre à basses températures et aux périodes de GD, dans le sol et les milieux aqueux. Bien qu'il existe une littérature abondante sur la survie des bactéries pathogènes à différentes conditions environnementales, on possède peu d'informations au sujet de leur transport dans les environnements d'eau souterraine à des températures basses et après GD. Ainsi, dans la deuxième partie du projet, l'effet de la température froide et l'effet des périodes GD répétés ont été étudiés sur les stratégies de survie telles que la mobilité et la formation de biofilms ainsi que la virulence des bactéries sélectionnées à Gram négatif et Gram positif . Les propriétés d'adhérence et le transport des bactéries exposées à des périodes de GD ont été étudiés à l'aide d'une microbalance à cristal de quartz avec mesure de la dissipation (QCM-D) et de l'eau contenue dans des colonnes saturées de sable. Les niveaux d'expression des différents gènes codant pour la synthèse de la flagelline, la production de la matrice extracellulaire et des facteurs de virulence ont été mesurés en utilisant la transcription par réaction en chaîne par polymérase inverse quantitative (qRT-PCR). Nos résultats démontrent que les bactéries présentent une plus grande rétention sur les grains de sable après l'exposition aux périodes de GD. En outre, les bactéries ont tendance à survivre pendant de longues périodes de temps et peuvent devenir plus virulent à basse température dans des eaux à plus grande force ionique posant ainsi une menace potentielle pour l'eau potable

Role of Climate and Freeze-Thaw on the Survival, Transport and Virulence of Yersinia enterocolitica

Surface and near-surface soils in cold climate regions experience low temperature and freeze–thaw (FT) conditions in the winter. Microorganisms that are of concern to groundwater quality may have the potential to survive low temperature and FT in the soil and aqueous environments. Although there is a body of literature on the survival of pathogenic bacteria at different environmental conditions, little is known about their transport behavior in aquatic environments at low temperatures and after FT. Herein, we studied the survival, transport, and virulence of a Gram-negative bacterial pathogen, Yersinia enterocolitica, when subjected to low temperature and several FT cycles at two solution ionic strengths (10 and 100 mM) in the absence of nutrients. Our findings demonstrate that this bacterium exhibited higher retention on sand after exposure to FT. Increasing the number of FT cycles resulted in higher bacterial cell surface hydrophobicity and impaired the swimming motility and viability of the bacterium.[...

Cranberry impairs selected behaviours essential for virulence in Proteus mirabilis H4320

Proteus mirabilis is an etiological agent of complicated urinary tract infections. North American cranberries (Vaccinium macrocarpon) have long been considered to have protective properties against urinary tract infections. This work reports the effects of cranberry powder (CP) on the motility of P. mirabilis HI4320 and its expression of flaA, flhD, and ureD. Our results show that swimming and swarming motilities and swarmer-cell differentiation were inhibited by CP. Additionally, transcription of the flagellin gene flaA and of flhD, the first gene of the flagellar master operon flhDC, decreased during exposure of P. mirabilis to various concentrations of CP. Moreover, using ureD-gfp, a fusion of the urease accessory gene ureD with gfp, we show that CP inhibits urease expression. Because we demonstrate that CP does not inhibit the growth of P. mirabilis, the observed effects are not attributable to toxicity. Taken together, our results demonstrate that CP hinders motility of P. mirabilis and reduces the expression of important virulence factors

Method for the Direct Observation and Quantification of Survival of Bacteria Attached to Negatively or Positively Charged Surfaces in an Aqueous Medium

The risk of groundwater contamination by microbial pathogens is linked to their survival in the subsurface. Although there is a large body of literature on the inactivation behavior of suspended (planktonic) microorganisms, little is known about the inactivation of bacteria when attached to sand grain surfaces in groundwater aquifers. The main goal of this study was to develop a fluorescence-based experimental technique for evaluating the extent of inactivation over time of bacteria adhered onto a surface in an aqueous environment. Key features of the developed technique are as follows: (i) attached cells do not need to be removed from the surface of interest for quantification, (ii) bacterial inactivation can be examined in real-time for prolonged time periods, and (iii) the system remains undisturbed (i.e., the aqueous environment is unchanged) during the assay. [...] The results of this work show that the developed technique is sensitive enough to distinguish between the inactivation kinetics of different representative bacteria attached to either a negatively charged (bare glass) surface or a positively charged (coated glass) surface. Hence, the technique can be used to characterize bacterial inactivation kinetics when attached to environmentally relevant surfaces over a broad range of groundwater chemistries

Electrochemical disinfection of bacteria-laden water using antimony-doped tin-tungsten-oxide electrodes

Electrochemical disinfection has been shown to be an efficient method with a shortrequired contact time for treatment of drinking water supplies, industrial raw water supplies, liquid foodstuffs, and wastewater effluents. In the present work, the electrochemical disinfection of saline water contaminated with bacteria was investigated in chloride-containing solutions using Sb-doped Sn80%-W20%-oxide anodes. The influence of current density, bacterial load, initial chloride concentration, solution pH, and the type of bacteria (E. coli D21, E. coli O157:H7, and E. faecalis) on disinfection efficacy was systematically examined. The impact of natural organic matter and a radical scavenger on the disinfection process was also examined. The electrochemical system was highly effective in bacterial inactivation for a 0.1 M NaCl solution contaminated with ∼107 CFU/mL bacteria by applying a current density ≥1 mA/cm2 through the cell.100% inactivation of E. coli D21 was achieved with a contact time of less than 60 s and power consumption of 48 Wh/m3, by applying a current density of 6 mA/cm2 in a 0.1 M NaCl solution contaminated with ∼107 CFU/mL. Reactive chlorine species as well as reactive oxygen species (e.g. hydroxyl radicals) generated in situ during the electrochemical process were determined to be responsible for inactivation of bacteria