Готові списки джерел за темами / Adhesion resistance

Добірка наукової літератури з теми "Adhesion resistance"

Автор: Grafiati

Опубліковано: 7 липня 2024

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Статті в журналах з теми "Adhesion resistance":

Yao, Ya Dong, Guang Fu Yin, Xiao Wei Cheng, and Xiang Li Gou. "Design and Properties of Fire-Proof Coating for Tunnels." Key Engineering Materials 336-338 (April 2007): 1753–55. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.1753.

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Silicate fireproof coatings for tunnels (FCT) have many eminent properties. But low adhesion strength and poor water/fire-resistance of this kind of materials largely limit its applications. Here we reported a new kind of FCT based on high alumina cement as principle adhesive, redispersible powder as assisting adhesive, ammonium polyphosphate as fire-retardant material, vermiculite as adiabatic padding, and magnesium hydroxide as assisting reagents. The influence of various experimental conditions on fire resistance, adhesion strength and water resistance were carefully studied. Results showed that dispersible emulsoid powder was a key component affecting adhesion strength and water resistance of FCT, whereas fire-retardant material posed significant effects on the fire resistance.

Chen, Shuang Lian, Guang Xue Chen, and Jiang Wen Liu. "Study on an Aliphatic Polyurethane Laminating Adhesive Based on Castor Oil." Applied Mechanics and Materials 262 (December 2012): 551–56. http://dx.doi.org/10.4028/www.scientific.net/amm.262.551.

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The first component of the Polyurethane adhesive was prepared with polyester polyol, polyether polyol ,castor oil and isophorone diisocyanate. And this component was mixed with the castor oil and its modified production to prepare a two-component solvent-free aliphatic polyurethane laminating adhesive. In this study, the influences of the copolymerization ratio of polyester/ether on viscosity, heat resistance, adhesion strength and boiling resistance were studied, as well as influences of castor oil and its modified production on curing speed and adhesion strength. The results showed that when proportion of polyether diol was 25% and castor oil was 50% of the total hydroxyl content of first component, the PU adhesive with lower viscosity, better reactivity and enhanced boiling resistance would be achieved. And with an appropriate amount of derivatives castor oil in second component, the curing speed and adhesion strength of the PU adhesive were significantly improved.

Hao, S., and L. M. Keer. "Rolling Contact Between Rigid Cylinder and Semi-Infinite Elastic Body With Sliding and Adhesion." Journal of Tribology 129, no. 3 (January 22, 2007): 481–94. http://dx.doi.org/10.1115/1.2736431.

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Based on a hybrid superposition of an indentation contact and a rolling contact an analytical procedure is developed to evaluate the effects of surface adhesion during steady-state rolling contact, whereby two analytic solutions have been obtained. The first solution is a Hertz-type rolling contact between a rigid cylinder and a plane strain semi-infinite elastic substrate with finite adhesion, which is a JKR-type rolling contact but without singular adhesive traction at the edges of the contact zone. The second solution is of a rolling contact with JKR singular adhesive traction. The theoretical solution indicates that, when surface adhesion exists, the friction resistance can be significant provided the external normal force is small. In addition to the conventional friction coefficient, the ratio between friction resistance force and normal force, this paper suggests an “adhesion friction coefficient” which is defined as the ratio between friction resistance force and the sum of the normal force and a function of maximum adhesive traction per unit area, elastic constant of the substrate, and contact area that is characterized by the curvature of the roller surface.

Li, Shuangshuang, Yanliang Zhao, Hailang Wan, Jianping Lin, and Junying Min. "Molecular Understanding of the Interfacial Interaction and Corrosion Resistance between Epoxy Adhesive and Metallic Oxides on Galvanized Steel." Materials 16, no. 8 (April 13, 2023): 3061. http://dx.doi.org/10.3390/ma16083061.

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The epoxy adhesive-galvanized steel adhesive structure has been widely used in various industrial fields, but achieving high bonding strength and corrosion resistance is a challenge. This study examined the impact of surface oxides on the interfacial bonding performance of two types of galvanized steel with Zn–Al or Zn–Al–Mg coatings. Scanning electron microscopy and X-ray photoelectron spectroscopy analysis showed that the Zn–Al coating was covered by ZnO and Al2O3, while MgO was additionally found on the Zn–Al–Mg coating. Both coatings exhibited excellent adhesion in dry environments, but after 21 days of water soaking, the Zn–Al–Mg joint demonstrated better corrosion resistance than the Zn–Al joint. Numerical simulations revealed that metallic oxides of ZnO, Al2O3, and MgO had different adsorption preferences for the main components of the adhesive. The adhesion stress at the coating–adhesive interface was mainly due to hydrogen bonds and ionic interactions, and the theoretical adhesion stress of MgO adhesive system was higher than that of ZnO and Al2O3. The corrosion resistance of the Zn–Al–Mg adhesive interface was mainly due to the stronger corrosion resistance of the coating itself, and the lower water-related hydrogen bond content at the MgO adhesive interface. Understanding these bonding mechanisms can lead to the development of improved adhesive-galvanized steel structures with enhanced corrosion resistance.

TONEGAWA, Toru, Takahiro ASAO, Shigeru NOMURA, and Daihei SUGITA. "Self-releasing Tape "Heat Resistance SELFA"." Journal of The Adhesion Society of Japan 51, no. 8 (2015): 396–99. http://dx.doi.org/10.11618/adhesion.51.396.

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Wen, Bor-Jiunn, Pen-Cheng Wang, and Pin-Hsuan Hung. "Numerical and experimental analysis of the effect of metal tie layers on improving electrical properties of gold coated poly (dimethylsiloxane) flexible multi-layered films during folding." Journal of Plastic Film & Sheeting 35, no. 2 (October 9, 2018): 135–56. http://dx.doi.org/10.1177/8756087918805790.

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To improve folding electrical properties of flexible electronics, this study presents a new adhesive stress analysis of depositing an adhesion layer between the conductive film electrode and the flexible substrate during folding test by a folding test platform. The folding test platform controls folding curvature of the flexible conductive substrates, folding times, and velocities in this study. Moreover, the electrical properties of flexible conductive substrates are measured during folding testing by the folding test platform. Eventually, this study successfully analyzes residual strain, adhesive stress, and electrical properties of flexible gold coated on polydimethylsiloxane substrates with chromium, nickel, and titanium adhesion layers up to 0.5/cm folding curvature during folding testing. The chromium adhesion layer had the best performance based on the largest adhesive stress, only 3.74 Ω resistance increase and 4.53 Ω maximum resistance up to 0.5/cm folding curvature during folding test by a folding test platform. The experimental result with chromium adhesion layer is consistent with adhesive stress analysis and provides a better adhesive strength between gold and polydimethylsiloxane than nickel and titanium materials for folding test. Therefore, adhesive stress analysis is adapted to evaluate the foldable electronics performance for improving folding characteristics easier.

OHBA, Shintaro. "Earth quake Resistance of Five-story Pagodas." Journal of The Adhesion Society of Japan 45, no. 5 (2009): 178–83. http://dx.doi.org/10.11618/adhesion.45.178.

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Jin, Biyu, Guangfa Zhang, Jiazhang Lian, Qinghua Zhang, Xiaoli Zhan, and Fengqiu Chen. "Boron nitride nanosheet embedded bio-inspired wet adhesives with switchable adhesion and oxidation resistance." Journal of Materials Chemistry A 7, no. 19 (2019): 12266–75. http://dx.doi.org/10.1039/c9ta02827g.

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Kolnes, Mart, Jakob Kübarsepp, Fjodor Sergejev, and Märt Kolnes. "Comparative Study of Adhesive Wear for CoCr, TiC-NiMo, WC-Co as Potential FSW Tool Materials." Solid State Phenomena 267 (October 2017): 224–28. http://dx.doi.org/10.4028/www.scientific.net/ssp.267.224.

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Friction stir welding is a novel and promising joining process and most common welding tool failure is transformation of geometry caused by wear. In our point of view, this is adhesion wear. The lathe testing of adhesion wear was conducted to compare wear resistance of following materials: Co-25wt%Cr, TiC-25wt%Ni/Mo and WC-6wt%Co. According to characteristics of investigated materials, they are capable to become alternatives for conventional frictional stir welding (FSW) tool materials. Adhesive wear tests were performed by turning aluminium alloy AW6082-T6 at low speed – travel length, turning speed and feed rate were selected to simulate FSW conditions. The adhesive wear was determined as the change of the geometry of the cutting edges of the tool measured using SEM images. Most promising tool material in terms of adhesion wear resistance is WC-Co hardmetal. The two main stages of wear were distinguished: at first, the appearance of intensive adhesion wear followed by steady state wear. Surface fatigue wear complements development of the adhesive wear.

Pradyawong, Sarocha, Guangyan Qi, Meng Zhang, Xiuzhi S. Sun, and Donghai Wang. "Effect of pH and pH-Shifting on Adhesion Performance and Properties of Lignin-Protein Adhesives." Transactions of the ASABE 64, no. 4 (2021): 1141–52. http://dx.doi.org/10.13031/trans.14465.

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HighlightsLignin improved the wet adhesion strength of soy protein adhesives when pH shifted from 8.5 to 4.5.Lignin increased the water resistance of soy protein adhesives from 5% to 40% at pH 12.Lignin improved the thermal resistance of soy protein adhesives.pH and pH-shifting treatments led to property changes of lignin, soy protein, and lignin-soy protein.Abstract. Concerns about public health and the environment have created strong interest in developing alternative green products. The focus of this research was to study the effect of lignin on soy protein (SP) adhesives under different pH and pH-shifting treatments. Additionally, this research was designed to understand the consequence of pH and pH-shifting treatments on the adhesion performance of SP and lignin-SP (LSP) adhesives as well as the characteristics, solubility, glue line patterns, and physiochemical properties. To study the aggregation, soluble, and denatured stages of protein, the protein solutions were adjusted to pH 4.5, 8.5, and 12, respectively. In addition, the study of pH-shifting treatments was performed at pH 8.5 and 12 to unfold and denature the protein, respectively. The protein structure was then refolded by adjusting the pH to 4.5 in adhesive slurries. The adhesives presented good adhesion performance under dry conditions with wood failure in most treatments, while satisfactory wet adhesion performance was obtained at pH 4.5, 8.5 to 4.5, and 12. Shifting the pH from 8.5 to 4.5 increased the lignin-protein interaction and provided the best improvement in adhesion performance. Lignin strengthened the protein structure, increased the water resistance, and improved the thermal stability of SP adhesives. At an extremely high pH, the water resistance of SP increased from 5% to 40% with the addition of lignin. Lignin showed great potential for increasing the wet strength of SP adhesives. The SP and LSP properties and adhesion performance could be adjusted and improved by pH and pH-shifting processes. Lignin-SP interactions, water resistance, and glue line pattern proved to be significant factors contributing to adhesion performance. Keywords: Adhesive, Lignin, Lignin-protein interactions, pH, pH-Shifting, Protein.

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Дисертації з теми "Adhesion resistance":

Lougheed, Caroline. "Targeting focal adhesion signaling in cancer and acquired resistance to focal adhesion kinase inhibitors." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=94996.

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In cancer progression, the development of metastases is characteristic of late stage disease and makes treatment and cure more difficult. In order for metastasis to occur, cancer cells must gain motile and invasive phenotypes. As one of the keystone proteins involved in cell motility and invasion, Focal Adhesion Kinase (FAK) has emerged as a good therapeutic target for the inhibition of metastases via targeted drug design and small molecule inhibitors. Accordingly, a small molecule inhibitor has recently been developed against FAK activation and signaling. However, drug resistance is common among targeted therapies. Development and classification of drug resistant cells elucidated the possible mechanism behind FAK inhibitor resistance such that second-line therapy drugs can be designed to overcome or avoid resistance. The overall data presented herein support the role of FAK as an important drug target in cancer metastasis as well as provide insight and direction for future FAK inhibitor design.
Dans la progression du cancer, le développement de métastases est caractéristique de la phase terminale et rend le traitement difficile. Afin que des métastases se dévelopment, les cellules cancéreuses doivent acquérir de la motilité ainsi qu'un phénotype invasif. Considéré come l'une des plus importantes protéines participant dans la motilité cellulaire, la prot éine Focal Adhesion Kinase (FAK) a émergé comme une bonne cible thérapeutique pour l'inhibition de métastases par la création de drogues ciblées et de petites molécules inhibitrices. Par conséquent, une molécule inhibitrice de l'activation de FAK et sa signalisation a été récemment développée. Cependant, J'ai demontré que la résistance est commune parmis ces drogues. Le dévelopement et la classification des clones de cellules résistantes ont permi d'élucider un mécanisme impiquant en partie une amplification de l'activité FAK; ce mécanisme permetter a de découvrir des analogues de deuxième génération pour surmonter ou éviter la résistance. L'ensemble de données présentées ci-dessous supportet le rôle de FAK comme une cible importante dans la prévention de métastases et exposent les futur directions pour contourner la résistance aux inhibiteurs de FAK.

Ahlberg, Jesper, and Esbjörn Blomquist. "Online Identification of Running Resistance and Available Adhesion of Trains." Thesis, Linköpings universitet, Fordonssystem, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-71301.

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Two important physical aspects that determine the performance of a running train are the total running resistance that acts on the whole train moving forward, and the available adhesion (utilizable wheel-rail-friction) for propulsion and breaking. Using the measured and available signals, online identification of the current running resistance and available adhesion and also prediction of future values for a distance ahead of the train, is desired. With the aim to enhance the precision of those calculations, this thesis investigates the potential of online identification and prediction utilizing the Extended Kalman Filter. The conclusions are that problems with observability and sensitivity arise, which result in a need for sophisticated methods to numerically derive the acceleration from the velocity signal. The smoothing spline approximation is shown to provide the best results for this numerical differentiation. Sensitivity and its need for high accuracy, especially in the acceleration signal, results in a demand of higher sample frequency. A desire for other profound ways of collecting further information, or to enhance the models, arises with possibilities of future work in the field.
Två viktiga fysikaliska aspekter som bestämmer prestandan för ett tåg i drift är det totala gångmotståndet som verkar på hela tåget, samt den tillgängliga adhesionen (användbara hjul-räl-friktionen) för framdrivning och bromsning. Från de tillgängliga signalerna önskas identifiering, samt prediktering, av dessa två storheter, under drift. Med målet att förbättra precisionen av dessa skattningar undersöker detta examensarbete potentialen av skattning och prediktering av gångmotstånd och adhesion med hjälp av Extended KalmanFiltering. Slutsatsen är att problem med observerbarhet och känslighet uppstår, vilket resulterar i ett behov av sofistikerade metoder att numeriskt beräkna acceleration från en hastighetssignal. Metoden smoothing spline approximation visar sig ge de bästa resultaten för denna numeriska derivering. Känsligheten och dess medförda krav på hög precision, speciellt på accelerationssignalen, resulterar i ett behov av högre samplingsfrekvens. Ett behov av andra adekvata metoder att tillföra ytterligare information, eller att förbättra modellerna, ger upphov till möjliga framtida utredningar inom området.

Munch, Sabine M. G. "Influence of interfacial adhesion on the fracture resistance of polymer multilayers." Thesis, Imperial College London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445160.

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St, Croix Bradley D. "Impact of intercellular adhesion on cell cycle and resistance to anticancer agents." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ35331.pdf.

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Ebert, Daniel Ray. "Superhydrophobic, Biomimetic Surfaces with High and Low Adhesion, Optical Transmittance, and Nanoscale Mechanical Wear Resistance." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1475516443008829.

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Nejmeh, Kassem. "Enhancing adhesion and Water Resistance in Clayey adhesives Mixtures : Strategies for Vertical and Horizontal Applications." Electronic Thesis or Diss., Université Gustave Eiffel, 2024. http://www.theses.fr/2024UEFL2012.

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Le matériau argileux est depuis longtemps privilégié dans la construction pour ses caractéristiques respectueuses de l'environnement. Les fines particules d'argile jouent un rôle crucial dans l'amélioration de la cohésion de ces matériaux. Cette recherche se concentre sur l'exploration de mélanges à base d'argile en tant que substituts potentiels aux adhésifs traditionnels pour carreaux utilisés sur des dalles de béton. L'objectif est de développer un matériau présentant une forte résistance à l'adhérence et maintenant son intégrité même lorsqu'il est immergé dans l'eau. Étant donné la nature poreuse du mélange d'argile, il est crucial de respecter des conditions de séchage spécifiques et des périodes d'immersion. La phase initiale de l'étude consiste à réaliser un test mécanique pour mesurer la contrainte d'adhérence du matériau avant et après immersion dans l'eau. Un échantillon de sol de référence sert de référence pour évaluer cette contrainte. Pour influencer les propriétés mécaniques, nous introduisons une quantité proportionnelle de polymères ou de fibres dans le sol de référence, dans le but de modifier ses propriétés de cohésion. La sélection de polymères ou de fibres est stratégique, dans le but d'induire des changements dans les propriétés mécaniques du matériau et sa résistance à l'eau. Dans la phase suivante, l'étude se concentre sur la compréhension du processus de séchage et de la cinétique d'imbibition après l'ajout de polymères. De plus, nous apportons des preuves que le choix du polymère affecte significativement la cinétique d'immersion et le degré d'absorption d'eau. L'approche de recherche se déroule en trois scénarios distincts : tout d'abord, nous renforçons la résistance du mortier en incorporant divers polymères et fibres ; deuxièmement, nous visons à empêcher l'absorption d'eau dans l'adhésif ; et enfin, nous nous efforçons de développer un adhésif réversible capable de retrouver sa résistance mécanique après avoir subi une perte due à l'immersion, uniquement grâce à un processus de séchage. De plus, nous concevons des stratégies spécifiques pour les différentes méthodes d'application, en abordant à la fois les applications verticales et horizontales
Earthen material has long been favored in building construction for its eco-friendly characteristics. Fine clay particles play a crucial role in enhancing the cohesion of such materials. This research focuses on exploring clay-based mixtures as potential substitutes for traditional tile adhesives used on concrete slabs. The objective is to develop a material that exhibits strong adhesion resistance and maintains its integrity even when submerged in water. Considering the porous nature of the clay mixture, adherence to specific drying conditions and immersion periods becomes crucial.The initial stage of the investigation involves conducting a mechanical test to measure the adhesive stress of the material before and after water immersion. A reference soil sample serves as the baseline for evaluating this stress. To influence the mechanical properties, we introduce a proportional amount of polymers or fibers into the reference soil, aiming to alter its cohesive attributes. The selection of polymers or fibers is strategic, intended to induce changes in the material's mechanical properties and its resistance to water.In the subsequent phase, the study focuses on understanding the drying process and imbibition kinetics following the addition of polymers. Additionally, we provide evidence that the choice of polymer significantly affects the kinetics of immersion and the degree of water absorption.The research approach unfolds in three distinctive scenarios: firstly, we enhance the strength of the mortar by incorporating diverse polymers and fibers; secondly, we aim to impede water absorption into the adhesive; and finally, we endeavor to develop a reversible adhesive capable of reclaiming its mechanical strength after experiencing loss due to immersion, solely through a drying process. Moreover, we devise strategies specific to different application methods, addressing both vertical and horizontal applications

Sun, Xiaowen. "An integrin-based mechanism for sensitizing melanomas to therapies." Diss., University of Iowa, 2015. https://ir.uiowa.edu/etd/6506.

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Metastatic melanoma is unusually lethal with a ten year survival rate of less than 10%. Conventional DNA-damaging agents produce little improvement in patient survival. Vemurafenib (Zelboraf), a targeted therapeutic that inhibits the oncogenic BRAF demonstrates significant survival benefit. Unfortunately, it is now evident that there is both intrinsic and acquired resistance. Consequently, new strategies for sensitizing melanomas to vemurafenib are needed. Melanoma resistance to therapy is fueled in part by the integrins, the major cell surface adhesion receptors which are highly over-expressed in melanoma. Both integrin antagonists and agents that engage defective integrins increase the sensitivity of melanomas to chemotherapy. Our laboratory has identified a novel peptide, denoted vinculin activating peptide or VAP that targets integrins from within the cell and brings aberrant integrin function intact. VAP sensitizes melanoma to dacarbazine in vitro and in vivo. The effect VAP has on overcoming resistance to targeted therapies like vemurafenib, as well as the mechanism for its effects are not well understood. The goals of this project are to determine if VAP can be employed to improve sensitivity and/or overcome resistance to vemurafenib and to identify the cell surface target of VAP. Our results show that VAP not only improves melanoma sensitivity to vemurafenib but also decreases intrinsic resistance to this promising drug. In addition, we present evidence that β1 and β3 integrins are the target of VAP's effects. Since peptide-based therapies are not stable in the clinic, we explored another integrin binding partner, kindlin-2. We found that kindlin-2 is over expressed in resistant melanomas. The inhibition of kindlin-2 increases β1 integrin activation and decreases β3 integrin functions. Agents that bring aberrant β1 and β3 integrin function intact can be employed to improve sensitivity and overcome resistance to vemurafenib suggesting that combinatorial therapies that employ vemurafenib and integrin-based agents might be efficacious in combatting resistance in melanoma patients.

Tan, Jiahong Brash John L. "Polyethylene oxide-containing block copolymers as surface modification additives in polyurethanes for protein and cell resistance /." *McMaster only, 2004.

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Klittich, Mena R. "Surface Interactions with Hierarchical Nanostructures: From Gecko Adhesion to Thermal Behavior." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1499440265902425.

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Nakanishi, Takao. "The synergistic role of ATP-dependent drug efflux pump and focal adhesion signaling pathways in vinorelbine resistance in lung cancer." Kyoto University, 2019. http://hdl.handle.net/2433/236608.

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Книги з теми "Adhesion resistance":

Buckley, Donald H. Adhesion and wear resistance of materials. [Cleveland, Ohio: National Aeronautics and Space Administration, Lewis Research Center, 1986.

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Buckley, Donald. Adhesion and wear resistance of materials. [s.l]: National Aeronautics and Space Administration, 1986.

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Jamieson, I. L. Advances in the understanding of binder-aggregate adhesion and resistance to stripping. Dublin: Environmental Research Unit, 1992.

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Croix, Bradley D. St. Impact of intercellular adhesion on cell cycle and resistance to anticancer agents. Ottawa: National Library of Canada = Bibliothèque nationale du Canada, 1998.

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Tielens, A. G. G. M. and United States. National Aeronautics and Space Administration., eds. Resistance to rolling in the adhesive contact of two elastic spheres. [Washington, DC: National Aeronautics and Space Administration, 1998.

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Theodore, Laufenberg, Lewis Research Center, and United States. Dept. of Energy. Wind/Ocean Technologies Division., eds. Improving the fatigue resistance of adhesive joints in laminated wood structures. Washington, D.C: U.S. Dept. of Energy, Conservation and Renewable Energy, Wind/Ocean Technology Division, 1988.

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Tielens, A. G. G. M. and United States. National Aeronautics and Space Administration., eds. Resistance to rolling in the adhesive contact of two elastic spheres. [Washington, D.C: National Aeronautics and Space Administration, 1995.

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United States. National Aeronautics and Space Administration., ed. Sulfur impurities and the microstructure of alumina scales. [Washington, DC]: National Aeronautics and Space Administration, 1997.

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United States. National Aeronautics and Space Administration., ed. Final report to NASA Marshall Space Flight Center on the study of low temperature unbalanced magnetron deposition of hard, wear-resistant coatings for liquid-film bearing applications: Contract number NAG8-1020. [Washington, DC: National Aeronautics and Space Administration, 1996.

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Kent), Harperset (Maidstone, ed. Abrasion-resistant & low-friction linings, employed to combat problems of wear and adhesion in the handling of bulk materials /composition and origination by Harperset, Maidstone, Kent. London: Loadstar, 1987.

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Частини книг з теми "Adhesion resistance":

Evirgen, Burak, Mustafa Tuncan, and Ahmet Tuncan. "In-Situ Evaluation of Adhesion Resistance in Anchor Root Zone." In Sustainable Civil Infrastructures, 181–90. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-030-01884-9_13.

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Gamski, K. "Resistance a Arrachement des Ancrages Fixes dans le Beton." In Adhesion between polymers and concrete / Adhésion entre polymères et béton, 641–49. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4899-3454-3_61.

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Czarnecki, L., and J. Grabowski. "Criterion of Cracking Resistance of Glass Fiber Reinforced Resins: A Comparative Study." In Adhesion between polymers and concrete / Adhésion entre polymères et béton, 152–65. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4899-3454-3_17.

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Lou, D. C., L. O. Finnerud, J. K. Solberg, O. M. Akselsen, and N. Dahl. "Adhesion Resistance of Particle Reinforced Steel Matrix Composite During Sliding Against Aluminium." In Friction, Wear and Wear Protection, 110–16. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2011. http://dx.doi.org/10.1002/9783527628513.ch12.

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Stanivukovic, B., and N. Knezevic-Vuksanovic. "Effets de l’Application de l’Enduit Epoxyde sur la Resistance l’Adherence lors de la Continuation du Betonnage." In Adhesion between polymers and concrete / Adhésion entre polymères et béton, 320–25. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4899-3454-3_34.

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Naseem, Z., K. Sagoe-Crentsil, and W. Duan. "Graphene-Induced Nano- and Microscale Modification of Polymer Structures in Cement Composite Systems." In Lecture Notes in Civil Engineering, 527–33. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-3330-3_56.

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AbstractRedispersible polymers such as ethylene–vinyl acetate copolymer (EVA) have attracted attention in construction due to their enhanced flexural strength, adhesion, flexibility and resistance against water penetration. However, EVA particles cluster in a highly alkaline cementitious matrix and exhibit poor interaction with the cement matrix. The underlying mechanism of poor dispersibility of EVA is attributed to hydrophobic groups of polymers, a variation in the adsorption rate and molecular diffusion to the interface where they cluster together. This phenomenon can negatively affect the fresh properties of cement and produce a weak microstructure, adversely affecting the resulting composites’ performance. This study highlights how graphene oxide (GO) nanomaterial alters the nano- and microscale structural characteristics of EVA to minimize the negative effects. Transmission electron microscopy (TEM) revealed that the GO sheets modify EVA’s clustered nanostructure and disperse it through electrostatic and steric interactions. Furthermore, scanning electron microscopy (SEM) confirmed altered microscale structural characteristics (viz. surface features) by GO. The altered and enhanced material scale engineering performance, such as the compressive strength of the resulting cement composite, was notable.

Burns, Barry. "Cyanoacrylates: Towards High Temperature Resistant Instant Adhesives. A Critical Review." In Progress in Adhesion and Adhesives, 341–68. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2018. http://dx.doi.org/10.1002/9781119526445.ch10.

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Zhitomirsky, V. N., I. Grimberg, M. C. Joseph, E. Gidalevich, R. L. Boxman, A. Matthews, S. Goldsmith, and B. Z. Weiss. "Vacuum arc plasma deposition of wear resistant coatings on polymer substrates." In Polymer Surface Modification: Relevance to Adhesion, Volume 2, 551–73. London: CRC Press, 2023. http://dx.doi.org/10.1201/9780429070419-33.

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Wang, Kaiming, Wei Liu, Xiaotong Pang, Yongle Hu, and Yonggang Tong. "Research Progress of Remanufacturing Technology in the Field of Construction Machinery." In Lecture Notes in Mechanical Engineering, 807–16. Singapore: Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-1876-4_63.

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AbstractExcavator bucket teeth are often in direct contact with abrasive particles in the soil during work, resulting in the tip being severely worn. This study used laser cladding to synthesize (Ti, Nb)C reinforced coatings on the surface of Q550 steel of bucket teeth of commonly used excavators to improve the wear resistance, and researches the effects of different Ti, Nb, Cr3C2 powder ratios on the hardness, wear resistance, and wear loss of laser cladding (Ti, Nb)C reinforced coatings. The results show that the optimal powder ratio is 80% Ni-based + 1.26% Ti + 7.54% Nb + 11.2% Cr3C2. Under the optimal powder ratio, the hardness of the coating is 213.4 HV, the wear amount is 32.7 mg, and the wear failure form is abrasive wear and slight adhesive wear.

Antosik, Adrian Krzysztof, Karolina Mozelweska, Marlena Musik, and Piotr Miądlicki. "Silicone Pressure-Sensitive Adhesives Modified with Halloysite of Increased Thermal Resistance." In 7th International Conference on Structural Adhesive Bonding 2023, 111–27. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-48363-9_8.

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Тези доповідей конференцій з теми "Adhesion resistance":

Öztoprak, Ece, and Kaan Öztoprak. "Comparison of Two Different Etch Systems as Adhesion Resistance in Dental Adhesive Systems." In The 9th International Conference on Advanced Materials and Systems. INCDTP - Leather and Footwear Research Institute (ICPI), Bucharest, Romania, 2022. http://dx.doi.org/10.24264/icams-2022.ii.18.

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Adhesive systems are used in many specialties in dentistry. These systems provide chemical attachment of prosthetic and restorative materials to the tooth surface. The first stage of adhesive systems is the etching process. In the commonly used Total etch systems, acid agent is applied to the tooth first to create roughness on the tooth surface, then the applied bond agent enters this rough surface to ensure retention. The acid agent used is 37% phosphoric acid gel. Normally, phosphoric acid is liquid. It should be applied in gel form in order to be applied in a controlled manner to a certain surface of the tooth and to remain on the desired surface for a long time. Commercially used phosphoric acid gels are produced by a single method and contain the carbomer chemical. Another way to produce gel is silicium dioxide. Acid gels produced with carbomer have a glossy appearance, while acids produced with Silicium have a matte appearance. In this study, we aimed to see the difference in retention of the phosphoric acid gel produced with silicium dioxide compared to the carbomeric acid gel. In this study, we prepared phosphoric acid gel with silicium dioxide and phosphoric acid with carbomer. In our study, 50 extracted caries-free human teeth were used. Orthodontic buttons were attached to the buccal surfaces of the teeth in 2 groups. Phosphoric acid gel prepared with Carbomer was applied for 40 seconds on 25 teeth and phosphoric acid gel prepared with silicium dioxide for 40 seconds on 25 teeth. Afterwards, the teeth were washed with water for 10 seconds and dried, and the orthodontic buttons were adhered with blue light for 40 seconds with Tokuyama bond and flowable composite, and a tensile test was applied to them. There was a statistically significant difference between the tensile force resistance of the buttons attached with two different methods. The teeth in which the gel prepared with silicium dioxide was used showed an average of 6% more resistance to tensile force than the other group. In this study, adhesion strength was measured for the first time by changing the gel base material in acid. We recommend this preparation of acids in adhesive systems, and we believe it can be beneficial for all dentists.

Majumder, Sumit, Nicol McGruer, and Geroge G. Adams. "Contact Resistance and Adhesion in a MEMS Microswitch." In STLE/ASME 2003 International Joint Tribology Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/2003-trib-0270.

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A multi-asperity model of the contact resistance in a MEMS microswitch has been developed. This model includes the effects of elastic and plastic deformation, adhesion, and scale-dependent constrictive resistance. The number of asperities in contact is small enough that a discrete, rather than a continuous, distribution of asperity heights is used. Due to the combined effects of plasticity and adhesion, the surface profile changes with repeated load and unload cycles. Furthermore, adhesion produces significant hysteresis in the contact resistance vs. contact force characteristics. Measurements of the contact resistance as a function of actuation voltage show good qualitative agreement with the model.

Morisawa, Y., and T. Maruyama. "Evaluation of Sprayed Coatings by Electrical Method." In ITSC 2012, edited by R. S. Lima, A. Agarwal, M. M. Hyland, Y. C. Lau, C. J. Li, A. McDonald, and F. L. Toma. ASM International, 2012. http://dx.doi.org/10.31399/asm.cp.itsc2012p0708.

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Abstract A method for evaluating the adhesion of metallic thermally sprayed coatings by measuring the electrical resistance of the coating sprayed on a metal substrate was carried out. The thermal sprayed coatings were made of zinc alloy on carbon steel substrates. The electrical resistance levels between the substrates and coatings were evaluated. The electrical resistance increases with increasing measurement time. The larger the rate of increase of the electrical resistance, the lower the adhesive strength. There is a possibility to evaluate qualitatively the adhesion properties.

Zolotarev, V. A. "Adhesive activity of bitumen with adhesion agent and its influence on asphalt concrete water-resistance." In Sixth International RILEM Symposium on Performance Testing and Evaluation of Bituminous Materials. RILEM Publications SARL, 2003. http://dx.doi.org/10.1617/2912143772.021.

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Kogut, L., and K. Komvopoulos. "Adhesion Analysis for MEMS Based on Electrical Contact Resistance Measurements." In STLE/ASME 2003 International Joint Tribology Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/2003-trib-0271.

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Because adhesion forces are especially important at the submicron scale, they play a dominant role in several fields of nanotechnology, such as biology, atomic force microscope (AFM) imaging, magnetic disk drives, and microelectromechanical systems (MEMS). The profound importance of adhesion forces in MEMS has been the principal theme of several studies. A common approach for measuring the surface energy is based on balancing the elastic energy stored in microcantilever beams partially adhered to substrates with the work of adhesion, assumed equal to the surface energy multiplied by the apparent area of the attached beam length. However, because the apparent contact area is significantly larger than the real contact area and the elastic energy stored in the deformed asperity microcontacts is neglected, this traditional method may greatly underestimate the interfacial adhesion energy. Consequently, the objective of this study was to develop a method for determining indirectly adhesion forces and adhesion energies form relatively simple in situ electrical contact resistance (ECR) measurements. The method presented herein is based on a theoretical treatment of the ECR encountered during contact of isotropic, conductive, rough surfaces, using multi-scale fractal description of the equivalent surface topography, constitutive contact relations for elastic-perfectly plastic asperity microcontacts, and size-dependent constriction resistance of microcontacts. Results are presented for the adhesion force and adhesion energy in terms of ECR for different surface topographies.

Pang, Yunsong, Meng Han, Ting Liang, Xue Bai, Liang Li, Yonglun Xu, Bin He, et al. "The Studys of Adhesion and Contact Thermal Resistance of TIM1." In 2021 22nd International Conference on Electronic Packaging Technology (ICEPT). IEEE, 2021. http://dx.doi.org/10.1109/icept52650.2021.9567907.

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Triani, Rafael Magalhães, Lucas Fuscaldi De Assis Gomes, Luiz Carlos Casteletti, Amadeu Lombardi Neto, and George Edward Totten. "Production and Characterization of Boride and Carbide Layers on AISI 15B30 Steel." In HT2019. ASM International, 2019. http://dx.doi.org/10.31399/asm.cp.ht2019p0200.

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Abstract In this work, boriding and Thermo-reactive Deposition (TRD) treatments for the production of boride and both vanadium and niobium carbide layers were performed on the substrates of AISI 15B30 steel to evaluate properties such as hardness, adhesive wear resistance, surface adhesion and chemical compounds present in the layers. For this purpose, layers were characterized by optical microscope, Knoop microhardness, microadhesive wear test, Rockwell C indentation adhesion according to VDI 3198 and X-ray diffraction. The results showed layers with high hardness (1400 - 2500 HK), greater microadhesive wear resistance (up to 15 times higher) when compared to the substrate and excellent delamination resistance.

Eid, H., L. Chen, N. Joshi, N. E. McGruer, and G. G. Adams. "Contact and Adhesion of Elastic-Plastic Layered Microsphere." In STLE/ASME 2010 International Joint Tribology Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ijtc2010-41203.

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A finite element contact model of a layered hemisphere with a rigid flat, which includes the effect of adhesion, is developed. This configuration has been suggested as a design for a microswitch contact because it has the potential to achieve low adhesion, low contact resistance, and high durability. Elastic-plastic material properties were used for each of the materials comprising the layered hemisphere. Adhesion was modeled based on the Lennard-Jones potential. The effect of the layer thickness on the adhesive contact was investigated. In particular the influence of layer thickness on the pull-off force and maximum contact radius was studied. The results are presented as load vs. interference and contact radius vs. interference for loading and unloading from different values of the maximum interference.

Chien, Heng-Chieh, Da-Jen Yao, and Cheng-Ting Hsu. "Study for the Interface Thermal Resistance of Metal-Dielectric Layers." In 2008 Second International Conference on Integration and Commercialization of Micro and Nanosystems. ASMEDC, 2008. http://dx.doi.org/10.1115/micronano2008-70280.

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In this Study, we measured the interface thermal resistance between metal/dielectric layers using a sandwiched structure. Common used metal thin films in MEMS including chromium, nickel, aluminum, titanium, and platinum, were sandwiched in between two PECVD SiO2 layers. Measured values of the interface thermal resistance distributed over the range of 2.5∼3.8×10−8 m2K/W. The continuum two-fluid model was served to provide some reasonable physical insight into the cause of metal/dielectric interface thermal resistance, and also to verify our measurement data. The estimated values are much smaller than the measured values. Moreover, the adhesion tests were implemented to verify the interrelation between the interface adhesion force and the measured interface thermal resistance. The results show the interface thermal resistance is very insensitivity to the adhesion force.

Smialek, James L. "Oxidation Resistance and Critical Sulfur Content of Single Crystal Superalloys." In ASME 1996 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/96-gt-519.

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Single crystal superalloys had greatly improved cyclic oxidation resistance when their sulfur content was reduced from impurity levels, typically 5–10 ppmw in past years, down to 1 ppmw or below currently. Excellent alumina scale adhesion has been documented for PWA 1480, PWA 1484, Rene’N5, Rene’N6, and CMSX 4, all without reactive element (Y) additions. Hydrogen annealing was used for effective desulfurization to below 0.1 ppmw, as well as for achieving controlled intermediate levels. This paper summarizes the direct relationship between cyclic oxidation behavior and sulfur content. An adhesion criterion has been proposed based on the concentration of sulfur needed to initiate spallation due to a monolayer of interfacial segregation. This suggests that a level down to ∼0.2 ppmw would be needed to maximize adhesion for a 1 mm thick sample. It is in reasonable agreement with the experimental results.

Звіти організацій з теми "Adhesion resistance":

Usov, Igor Olegovich, David M. Waschezyn, Douglas R. Vodnik, Robert Ryan Waked, Michael Robert Middlemas, Matthew M. Schneider, and Terry George Holesinger. Adhesion, microstructure and electrical resistance of sputtered Cu films on alumina substrates. Office of Scientific and Technical Information (OSTI), September 2019. http://dx.doi.org/10.2172/1569566.

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Rahimipour, Shai, and David Donovan. Renewable, long-term, antimicrobial surface treatments through dopamine-mediated binding of peptidoglycan hydrolases. United States Department of Agriculture, January 2012. http://dx.doi.org/10.32747/2012.7597930.bard.

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There is a need for renewable antimicrobial surface treatments that are semi- permanent, can eradicate both biofilms and planktonic pathogens over long periods of time and that do not select for resistant strains. This proposal describes a dopamine binding technology that is inexpensive, bio-friendly, non-toxic, and uses straight-forward commercially available products. The antimicrobial agents are peptidoglycanhydrolase enzymes that are non-toxic and highly refractory to resistance development. The goal of this project is to create a treatment that will be applicable to a wide variety of surfaces and will convey long-lasting antimicrobial activity. Although the immediate goal is to create staphylolytic surfaces, the technology should be applicable to any pathogen and will thus contribute to no less than 3 BARD priorities: 1) increased animal production by protecting animals from invasive and emerging diseases, 2) Antimicrobial food packaging will improve food safety and security and 3) sustainable bio- energy systems will be supported by coating fermentation vats with antimicrobials that could protect ethanolic fermentations from Lactobacillus contamination that reduces ethanol yields. The dopamine-based modification of surfaces is inspired by the strong adhesion of mussel adhesion proteins to virtually all types of surfaces, including metals, polymers, and inorganic materials. Peptidoglycanhydrolases (PGHs) meet the criteria of a surface bound antimicrobial with their site of action being extracellular peptidoglycan (the structural basis of the bacterial cell wall) that when breached causes osmotic lysis. As a proof of principle, we will develop technology using peptidoglycanhydrolase enzymes that target Staphylococcus aureus, a notoriously contagious and antimicrobial-resistant pathogen. We will test for susceptibility of the coating to a variety of environmental stresses including UV light, abrasive cleaning and dessication. In order to avoid resistance development, we intend to use three unique, synergistic, simultaneous staphylococcal enzyme activities. The hydrolases are modular such that we have created fusion proteins with three lytic activities that are highly refractory to resistance development. It is essential to use multiple simultaneous activities to avoid selecting for antimicrobial resistant strains. This strategy is applicable to both Gram positive and negative pathogens. We anticipate that upon completion of this award the technology will be available for commercialization within the time required to achieve a suitable high volume production scheme for the required enzymes (~1-2 years). We expect the modified surface will remain antimicrobial for several days, and when necessary, the protocol for renewal of the surface will be easily applied in a diverse array of environments, from food processing plants to barnyards.

Glazer, Itamar, Alice Churchill, Galina Gindin, and Michael Samish. Genomic and Organismal Studies to Elucidate the Mechanisms of Infectivity of Entomopathogenic Fungi to Ticks. United States Department of Agriculture, January 2013. http://dx.doi.org/10.32747/2013.7593382.bard.

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The overall goal of this research was to elucidate the factors affecting early development of Metarhizium spp. (previously named M. anisopliae) on ticks or tick cuticle extracts and the molecular basis of these early infection processes. The original objectives were: 1. Characterize the pre-penetration events (adhesion, germination and appressorium formation) of spores of M. anisopliae strains with high or low virulence during tick infection. 2. Create GFP-expressing strains of M. anisopliae tick pathogens having high and low virulence to compare their progress of infection by microscopy. 3. Use microarray analyses, primarily with existing M. anisopliae EST sequences in GenBank, to identify and characterize fungal genes whose expression is regulated in response to host cuticle extracts. Objective 3 was later modified (as approved by BARD) to use RNAseq to characterize the early stages of fungal gene expression during infection of intact host cuticles. This new method provides a massively larger and more informative dataset and allows us to take advantage of a) recently published genomes of Metarhizium robertsii and M. acridum for RNAseq data analysis, and b) newly developed and highly efficient cDNA sequencing technologies that are relatively low cost and, therefore, allow deep sequencing of multiple transcriptome samples. We examined pre-penetration and penetration events that differentiate high and low virulence strains of Metarhizium spp., focusing on spore adhesion, germination, appressorium formation, and penetration of tick integuments. Initiation of fungal infection was compared on susceptible and resistant tick species at different tick developmental stages. In vitro studies comparing the effects of protein and fatty acid profiles from tick cuticle extracts demonstrated that resistant tick cuticles contain higher concentrations of specific lipids that inhibit fungal development than do susceptible tick cuticles, suggesting one mechanism of Ixodidae resistance to fungal entomopathogens (Objective 1). We used molecular markers to determine that the three M. anisopliae strains from Israel that we studied actually were three distinct species. M. brunneum is highly virulent against the tick Rhipicephalus annulatus, M. pingshaense and M. robertsii are intermediate in virulence, and M. majus is of low virulence. We transformed all four Metarhizium species to express GFP and used them in pathogenicity assays against diverse tick species. Key findings were that a) resistant ticks inhibit Metarhizium infection prior to hemocoel invasion by reducing fungal viability on the cuticle surface (Objective 2), as was supported by the in vitro studies of Objective 1, and b) Metarhizium kills susceptible ticks after cuticle penetration but prior to hemocoel colonization. Transcriptome studies of the most virulent species, M. brunneum, are in progress and include analyses of ungerminated conidia and conidia germination and development on a low nutrient medium or on susceptible R. annulatus exoskeleton (Objective 3). We anticipate these studies will contribute to identifying fungal genetic factors that increase virulence and speed of kill and may help reveal tick chemistries that could be included in biocontrol formulations to increase efficacy. Methodologies developed to screen tick cuticle extracts for ability to support conidia germination and development may help in the selection of wild fungi with increased virulence against resistant ticks. The overall knowledge gained should contribute not only to the improvement of tick control but also to the control of other blood-sucking arthropods and related plant pests. Use of bio-based agents for controlling arthropods will contribute to a healthier, more sustainable environment and serve a growing number of organic food farmers.

Miller, Mr Michael J. DTPH56-06-T-000017 In-Field Welding and Coating Protocols. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), May 2009. http://dx.doi.org/10.55274/r0012117.

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Gas Technology Institute (GTI) and Edison Welding Institute (EWI) created both laboratory and infield girth weld samples to evaluate the effects of weld geometry and hydrogen off-gassing on the performance of protective coatings. Laboratory-made plate welds were used to tightly control geometric differences and in-field welds were created to mimic real-world welding conditions and hydrogen off-gassing rates. These welds were then coated and tested with accelerated corrosion techniques to evaluate the coatings' effectiveness. Simulated girth welds investigated geometric effects on the performance of a liquid-applied coating. Welds were created, coated, and testing in a salt-fog environment to accelerate corrosion. Undercuts up to 0.03 inches were found to have no significant effect on coatings' resistance to corrosion. On the contrary, the undercut tended to add to the coating thickness and therefore increased corrosion resistance. Increasing cap height of a weld was found to thin the coating making it more susceptible to chipping but no more susceptible to corrosion. If applying proper coating procedures, especially surface profiling, the weld geometries investigated here had no strong negative effects on a liquid applied two-part epoxy coating's performance. Since fusion-bonded epoxy (FBE) coatings are applied in a different manner, these results cannot be extended from liquid to FBE coatings. If the FBE provides the same wetting of the undercut and similar coating thickness on the cap height one would expect similar results. In-field welds were created to test the effects of hydrogen off-gassing on coating performance. Two different welding mediums were used, one with a high hydrogen content and one with low hydrogen content. These different welds were then held for 2 or 5 hours to vary the amount of time allowed for hydrogen off-gassing and then coated in either FBE or a liquid 2 part epoxy. All other variables were held constant. Cross-sectional analysis of coated 24-inch diameter pipes showed no increase of voids above the welded area, indicating there was little off-gassing in these samples. Cathodic Disbondment Testing, per ASTM G-95, was performed to evaluate the coating's adhesion properties. No detectable adhesion differences were found that could be attributed to the hydrogen off-gassing from the weld, instead, the results were more dependent on the coating thickness. Within the scope/boundary of the completed research, a hold time of two hours is sufficient to minimize any hydrogen off-gassing effects. Within the parameters of the in-field welds and simulated welds, no major detrimental effects were found from hydrogen off-gassing and weld geometries. However, the higher cap-height did make coatings more susceptible to damage when handling. This confirms previous GTI research which indicated that coatings often accrue damage during handling. GTI and EWI, taking into consideration the survey and testing results produced a recommendation to be distributed to various stakeholders in the pipeline industry. The summary document to be disturbed is located in the Recommendation section of this report.

Shpigel, Nahum, Raul Barletta, Ilan Rosenshine, and Marcelo Chaffer. Identification and characterization of Mycobacterium paratuberculosis virulence genes expressed in vivo by negative selection. United States Department of Agriculture, January 2004. http://dx.doi.org/10.32747/2004.7696510.bard.

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Mycobacterium avium subsp. paratuberculosis (MAP) is the etiological agent of a severe inflammatory bowel disease (IBD) in ruminants, known as Johne’s disease or paratuberculosis. Johne’s disease is considered to be one of the most serious diseases affecting dairy cattle both in Israel and worldwide. Heavy economic losses are incurred by dairy farmers due to the severe effect of subclinical infection on milk production, fertility, lower disease resistance and early culling. Its influence in the United States alone is staggering, causing an estimated loss of $1.5 billion to the agriculture industry every year. Isolation of MAP from intestinal tissue and blood of Crohn's patients has lead to concern that it plays a potential pathogenic role in promoting human IDB including Crohn’s disease. There is great concern following the identification of the organism in animal products and shedding of the organism to the environment by subclinically infected animals. Little is known about the molecular basis for MAP virulence. The goal of the original proposed research was to identify MAP genes that are required for the critical stage of initial infection and colonization of ruminants’ intestine by MAP. We proposed to develop and use signature tag mutagenesis (STM) screen to find MAP genes that are specifically required for survival in ruminants upon experimental infection. This research projected was approved as one-year feasibility study to prove the ability of the research team to establish the animal model for mutant screening and alternative in-vitro cell systems. In Israel, neonatal goat kids were repeatedly inoculated with either one of the following organisms; MAP K-10 strain and three transposon mutants of K-10 which were produced and screened by the US PI. Six months after the commencement of inoculation we have necropsied the goats and taken multiple tissue samples from the jejunum, ileum and mesenteric lymph nodes. Both PCR and histopathology analysis indicated on efficient MAP colonization of all the inoculated animals. We have established several systems in the Israeli PI’s laboratory; these include using IS900 PCR for the identification of MAP and using HSP65-based PCR for the differentiation between MAV and MAP. We used Southern blot analysis for the differentiation among transposon mutants of K-10. In addition the Israeli PI has set up a panel of in-vitro screening systems for MAP mutants. These include assays to test adhesion, phagocytosis and survival of MAP to/within macrophages, assays that determine the rate of MAPinduced apoptosis of macrophages and MAP-induced NO production by macrophages, and assays testing the interference with T cell ã Interferon production and T cell proliferation by MAP infected macrophages (macrophage studies were done in BoMac and RAW cell lines, mouse peritoneal macrophages and bovine peripheral blood monocytes derived macrophages, respectively). All partners involved in this project feel that we are currently on track with this novel, highly challenging and ambitious research project. We have managed to establish the above described research systems that will clearly enable us to achieve the original proposed scientific objectives. We have proven ourselves as excellent collaborative groups with very high levels of complementary expertise. The Israeli groups were very fortunate to work with the US group and in a very short time period to master numerous techniques in the field of Mycobacterium research. The Israeli group has proven its ability to run this complicated animal model. This research, if continued, may elucidate new and basic aspects related to the pathogenesis MAP. In addition the work may identify new targets for vaccine and drug development. Considering the possibility that MAP might be a cause of human Crohn’s disease, better understanding of virulence mechanisms of this organism might also be of public health interest as well.

Shomer, Ilan, Ruth E. Stark, Victor Gaba, and James D. Batteas. Understanding the hardening syndrome of potato (Solanum tuberosum L.) tuber tissue to eliminate textural defects in fresh and fresh-peeled/cut products. United States Department of Agriculture, November 2002. http://dx.doi.org/10.32747/2002.7587238.bard.

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The project sought to understand factors and mechanisms involved in the hardening of potato tubers. This syndrome inhibits heat softening due to intercellular adhesion (ICA) strengthening, compromising the marketing of industrially processed potatoes, particularly fresh peeled-cut or frozen tubers. However, ICA strengthening occurs under conditions which are inconsistent with the current ideas that relate it to Ca-pectate following pectin methyl esterase (PME) activity or to formation of rhamnogalacturonan (RG)-II-borate. First, it was necessary to induce strengthening of the middle lamellar complex (MLX) and the ICA as a stress response in some plant parenchyma. As normally this syndrome does not occur uniformly enough to study it, we devised an efficient model in which ICA-strengthening is induced consistently under simulated stress by short-chain, linear, mono-carboxylic acid molecules (OAM), at 65 oC [appendix 1 (Shomer&Kaaber, 2006)]. This rapid strengthening was insufficient for allowing the involved agents assembly to be identifiable; but it enabled us to develop an efficient in vitro system on potato tuber parenchyma slices at 25 ºC for 7 days, whereas unified stress was reliably simulated by OAMs in all the tissue cells. Such consistent ICA-strengthening in vitro was found to be induced according to the unique physicochemical features of each OAM as related to its lipophilicity (Ko/w), pKa, protonated proportion, and carbon chain length by the following parameters: OAM dissociation constant (Kdiss), adsorption affinity constant (KA), number of adsorbed OAMs required for ICA response (cooperativity factor) and the water-induced ICA (ICAwater). Notably, ICA-strengthening is accompanied by cell sap leakage, reflecting cell membrane rupture. In vitro, stress simulation by OAMs at pH<pKa facilitated the consistent assembly of ICAstrengthening agents, which we were able to characterize for the first time at the molecular level within purified insoluble cell wall of ICA-strengthened tissue. (a) With solid-state NMR, we established the chemical structure and covalent binding to cell walls of suberin-like agents associated exclusively with ICA strengthening [appendix 3 (Yu et al., 2006)]; (b) Using proteomics, 8 isoforms of cell wall-bound patatin (a soluble vacuolar 42-kDa protein) were identified exclusively in ICA-strengthened tissue; (c) With light/electron microscopy, ultrastructural characterization, histochemistry and immunolabeling, we co-localized patatin and pectin in the primary cell wall and prominently in the MLX; (d) determination of cell wall composition (pectin, neutral sugars, Ca-pectate) yielded similar results in both controls and ICA-strengthened tissue, implicating factors other than PME activity, Ca2+ or borate ions; (e) X-ray powder diffraction experiments revealed that the cellulose crystallinity in the cell wall is masked by pectin and neutral sugars (mainly galactan), whereas heat or enzymatic pectin degradation exposed the crystalline cellulose structure. Thus, we found that exclusively in ICA-strengthened tissue, heat-resistant pectin is evident in the presence of patatin and suberinlike agents, where the cellulose crystallinity was more hidden than in fresh control tissue. Conclusions: Stress response ICA-strengthening is simulated consistently by OAMs at pH< pKa, although PME and formation of Ca-pectate and RG-II-borate are inhibited. By contrast, at pH>pKa and particularly at pH 7, ICA-strengthening is mostly inhibited, although PME activity and formation of Ca-pectate or RG-II-borate are known to be facilitated. We found that upon stress, vacuolar patatin is released with cell sap leakage, allowing the patatin to associate with the pectin in both the primary cell wall and the MLX. The stress response also includes formation of covalently bound suberin-like polyesters within the insoluble cell wall. The experiments validated the hypotheses, thus led to a novel picture of the structural and molecular alterations responsible for the textural behavior of potato tuber. These findings represent a breakthrough towards understanding of the hardening syndrome, laying the groundwork for potato-handling strategies that assure textural quality of industrially processed particularly in fresh peeled cut tubers, ready-to-prepare and frozen preserved products.