Letteratura scientifica selezionata sul tema "Substrate transfert"
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Articoli di riviste sul tema "Substrate transfert":
1
Liu, Shuzhen, Bingwen Liu, Yin Zhu, Yong Qiu e Bing Li. "The Spatial–Temporal Effects of Bacterial Growth Substrates on Antibiotic Resistance Gene Spread in the Biofilm". Antibiotics 12, n. 7 (6 luglio 2023): 1154. http://dx.doi.org/10.3390/antibiotics12071154.
Abstract (sommario):
Biofilm is considered as the hotspot of antibiotic resistance gene (ARG) dissemination. Bacterial growth substrates are important factors for biofilm formation, but its spatial–temporal effects on ARG spread in biofilm is still unclear. In this study, microfluidics combined with microscopic observation were used to reveal spatial–temporal effects of bacterial growth substrates on ARG transfer at real time. The initial horizontal gene transfer events were found to be independent of substrate levels. However, subsequent transfer processes varied greatly depending on the availability of growth substrates. The proportion of transconjugants was much higher (~12%) when observed in substrate-rich regions (under the channel) at 24 h, followed by an exponential decline, with the distance far from the channel. Furthermore, three-dimensional observation revealed that vertical gene transfer influenced by the concentrations of bacterial growth substrates was important for ARG spread in biofilm. The transfer frequency was 8.2 times higher in the high substrate concentration (50×) compared to low concentration (0.5×) in simulated sewage, underscoring the substantial impact of bacterial growth substrate variability on ARG dissemination. This study is helpful for in-depth understanding of ARG dissemination through biofilms and indicates that reducing pollutant emission is important for ARG control in the environment.
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Liao, Michael Evan, Kenny Huynh, Brandon Carson, Lezli Matto, Kaicheng Pan, James Spencer Lundh, Marko Tadjer, Karl D. Hobart e Mark S. Goorsky. "Towards Controlled Transfer of (001) β-Ga2O3 to (0001) 4H-SiC Substrates". ECS Transactions 112, n. 3 (29 settembre 2023): 269–78. http://dx.doi.org/10.1149/11203.0269ecst.
Abstract (sommario):
We demonstrate successful surface blistering of He-implanted (001) β-Ga2O3 substrates, bonding to (0001) 4H-SiC, and initial results towards large-area transfer of (001) β-Ga2O3 to 4H-SiC. Surface blistering of unbonded, implanted substrates is an important indication of successful exfoliation and transfer of films, which is achieved by initiating He bubble nucleation during a low temperature anneal followed by bubble growth at a high temperature anneal. Prior to annealing, implanted substrates were bonded to (0001) 4H-SiC at room temperature using a thin ~5 nm Ti interlayer. However, the β-Ga2O3 substrate did not wafer split from the bonded structure after annealing. Instead, small area transfers up to ~200 μm were achieved (~7% of the total bonded area transferred while the entire structure remained bonded). Further optimization of implant parameters is underway. These are promising results towards achieving large wafer-scale (001) β-Ga2O3 composite wafers suitable for β-Ga2O3 devices with efficient thermal management characteristics.
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Girasek, Tomas, Alena Pietrikova, Tilo Welker e Jens Muller. "Simulation of Heat Transfer by Cooling Channels in LTCC Substrate". Acta Electrotechnica et Informatica 17, n. 2 (1 giugno 2017): 11–15. http://dx.doi.org/10.15546/aeei-2017-0010.
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Jakubowski, Simon J., Eric Cascales, Vidhya Krishnamoorthy e Peter J. Christie. "Agrobacterium tumefaciens VirB9, an Outer-Membrane-Associated Component of a Type IV Secretion System, Regulates Substrate Selection and T-Pilus Biogenesis". Journal of Bacteriology 187, n. 10 (15 maggio 2005): 3486–95. http://dx.doi.org/10.1128/jb.187.10.3486-3495.2005.
Abstract (sommario):
ABSTRACT Agrobacterium tumefaciens translocates DNA and protein substrates between cells via a type IV secretion system (T4SS) whose channel subunits include the VirD4 coupling protein, VirB11 ATPase, VirB6, VirB8, VirB2, and VirB9. In this study, we used linker insertion mutagenesis to characterize the contribution of the outer-membrane-associated VirB9 to assembly and function of the VirB/D4 T4SS. Twenty-five dipeptide insertion mutations were classified as permissive for intercellular substrate transfer (Tra+), completely transfer defective (Tra−), or substrate discriminating, e.g., selectively permissive for transfer only of the oncogenic transfer DNA and the VirE2 protein substrates or of a mobilizable IncQ plasmid substrate. Mutations inhibiting transfer of DNA substrates did not affect formation of close contacts of the substrate with inner membrane channel subunits but blocked formation of contacts with the VirB2 and VirB9 channel subunits, which is indicative of a defect in assembly or function of the distal portion of the secretion channel. Several mutations in the N- and C-terminal regions disrupted VirB9 complex formation with the outer-membrane-associated lipoprotein VirB7 or the inner membrane energy sensor VirB10. Several VirB9.i2-producing Tra+ strains failed to elaborate T pilus at detectable levels (Pil−), and three such Tra+ Pil− mutant strains were rendered Tra− upon deletion of virB2, indicating that the cellular form of pilin protein is essential for substrate translocation. Our findings, together with computer-based analyses, support a model in which distinct domains of VirB9 contribute to substrate selection and translocation, establishment of channel subunit contacts, and T-pilus biogenesis.
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Butzerin, Andre, Sascha Weikert e Konrad Wegener. "Growth Substrate Geometry Optimization for the Productive Mechanical Dry Transfer of Carbon Nanotubes". Processes 12, n. 5 (1 maggio 2024): 928. http://dx.doi.org/10.3390/pr12050928.
Abstract (sommario):
The selection of growth substrate geometries for the mechanical dry transfer of carbon nanotubes to device substrates depends on the precision of the assembly equipment. Since these geometries play a decisive role in the overall efficiency of the process, an investigation of the most important geometry parameters is carried out. The substrate geometry affects the number of carbon nanotubes suspended during the growth process and the speed of mechanical assembly at the same time. Since those two criteria are interlinked and affect productivity, a meta-model for the growth and selection of the nanotubes is simulated and a time study of the resulting assembly motions is subsequently performed. The geometry parameters are then evaluated based on the total number of suspended carbon nanotubes and the throughput rate, measured in transfers per hour. The accuracy specifications are then taken into account. Depending on the overall accuracy that can be achieved, different offset angles and overlaps between the growth and receiving substrate can be reached, which affect productivity differently for different substrate geometries. To increase the overall productivity, growth substrate designs are adapted to allow fully automated operation. This measure also reduces the frequency of substrate exchanges once all carbon nanotubes have been harvested. The introduction of substrates with multiple, polygonally arranged edges increases the total number of nanotubes that can be harvested. The inclusion of polygonally arranged edges in the initial analysis shows a significant increase in overall productivity.
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Liu, Yang, Keying Long, Hanbing Mi, Ruitao Cha e Xingyu Jiang. "High-efficiency transfer of fingerprints from various surfaces using nanofibrillated cellulose". Nanoscale Horizons 4, n. 4 (2019): 953–59. http://dx.doi.org/10.1039/c8nh00494c.
Abstract (sommario):
Fingerprint transfer and detection by fluorescent NFC/CDs paper. Compared with cyanoacrylate fuming and dusting with black powder, we can transfer clear fingerprint patterns from rubber substrate onto NFC/CDs paper. The results of feature points extraction and similarity assessment show that 80% of the feature can transfer from smooth substrates and 60% from rough substrates.
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Whitaker, Neal, Yuqing Chen, Simon J. Jakubowski, Mayukh K. Sarkar, Feng Li e Peter J. Christie. "The All-Alpha Domains of Coupling Proteins from the Agrobacterium tumefaciens VirB/VirD4 and Enterococcus faecalis pCF10-Encoded Type IV Secretion Systems Confer Specificity to Binding of Cognate DNA Substrates". Journal of Bacteriology 197, n. 14 (4 maggio 2015): 2335–49. http://dx.doi.org/10.1128/jb.00189-15.
Abstract (sommario):
ABSTRACTBacterial type IV coupling proteins (T4CPs) bind and mediate the delivery of DNA substrates through associated type IV secretion systems (T4SSs). T4CPs consist of a transmembrane domain, a conserved nucleotide-binding domain (NBD), and a sequence-variable helical bundle called the all-alpha domain (AAD). In the T4CP structural prototype, plasmid R388-encoded TrwB, the NBD assembles as a homohexamer resembling RecA and DNA ring helicases, and the AAD, which sits at the channel entrance of the homohexamer, is structurally similar to N-terminal domain 1 of recombinase XerD. Here, we defined the contributions of AADs from theAgrobacterium tumefaciensVirD4 andEnterococcus faecalisPcfC T4CPs to DNA substrate binding. AAD deletions abolished DNA transfer, whereas production of the AAD in otherwise wild-type donor strains diminished the transfer of cognate but not heterologous substrates. Reciprocal swaps of AADs between PcfC and VirD4 abolished the transfer of cognate DNA substrates, although strikingly, the VirD4-AADPcfCchimera (VirD4 with the PcfC AAD) supported the transfer of a mobilizable plasmid. Purified AADs from both T4CPs bound DNA substrates without sequence preference but specifically bound cognate processing proteins required for cleavage at origin-of-transfer sequences. The soluble domains of VirD4 and PcfC lacking their AADs neither exerted negative dominancein vivonor specifically bound cognate processing proteinsin vitro. Our findings support a model in which the T4CP AADs contribute to DNA substrate selection through binding of associated processing proteins. Furthermore, MOBQ plasmids have evolved a docking mechanism that bypasses the AAD substrate discrimination checkpoint, which might account for their capacity to promiscuously transfer through many different T4SSs.IMPORTANCEFor conjugative transfer of mobile DNA elements, members of the VirD4/TraG/TrwB receptor superfamily bind cognate DNA substrates through mechanisms that are largely undefined. Here, we supply genetic and biochemical evidence that a helical bundle, designated the all-alpha domain (AAD), of T4SS receptors functions as a substrate specificity determinant. We show that AADs from two substrate receptors,Agrobacterium tumefaciensVirD4 andEnterococcus faecalisPcfC, bind DNA without sequence or strand preference but specifically bind the cognate relaxases responsible for nicking and piloting the transferred strand through the T4SS. We propose that interactions of receptor AADs with DNA-processing factors constitute a basis for selective coupling of mobile DNA elements with type IV secretion channels.
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Whitaker, Neal, Trista M. Berry, Nathan Rosenthal, Jay E. Gordon, Christian Gonzalez-Rivera, Kathy B. Sheehan, Hilary K. Truchan et al. "Chimeric Coupling Proteins Mediate Transfer of Heterologous Type IV Effectors through the Escherichia coli pKM101-Encoded Conjugation Machine". Journal of Bacteriology 198, n. 19 (18 luglio 2016): 2701–18. http://dx.doi.org/10.1128/jb.00378-16.
Abstract (sommario):
ABSTRACTBacterial type IV secretion systems (T4SSs) are composed of two major subfamilies, conjugation machines dedicated to DNA transfer and effector translocators for protein transfer. We show here that theEscherichia colipKM101-encoded conjugation system, coupled with chimeric substrate receptors, can be repurposed for transfer of heterologous effector proteins. The chimeric receptors were composed of the N-terminal transmembrane domain of pKM101-encoded TraJ fused to soluble domains of VirD4 homologs functioning inAgrobacterium tumefaciens,Anaplasma phagocytophilum, orWolbachia pipientis. A chimeric receptor assembled fromA. tumefaciensVirD4 (VirD4At) mediated transfer of a MOBQ plasmid (pML122) andA. tumefacienseffector proteins (VirE2, VirE3, and VirF) through the pKM101 transfer channel. Equivalent chimeric receptors assembled from the rickettsial VirD4 homologs similarly supported the transfer of known or candidate effectors from rickettsial species. These findings establish a proof of principle for use of the dedicated pKM101 conjugation channel, coupled with chimeric substrate receptors, to screen for translocation competency of protein effectors from recalcitrant species. Many T4SS receptors carry sequence-variable C-terminal domains (CTDs) with unknown function. While VirD4Atand the TraJ/VirD4Atchimera with their CTDs deleted supported pML122 transfer at wild-type levels, ΔCTD variants supported transfer of protein substrates at strongly diminished or elevated levels. We were unable to detect binding of VirD4At's CTD to the VirE2 effector, although other VirD4Atdomains bound this substratein vitro. We propose that CTDs evolved to govern the dynamics of substrate presentation to the T4SS either through transient substrate contacts or by controlling substrate access to other receptor domains.IMPORTANCEBacterial type IV secretion systems (T4SSs) display striking versatility in their capacity to translocate DNA and protein substrates to prokaryotic and eukaryotic target cells. A hexameric ATPase, the type IV coupling protein (T4CP), functions as a substrate receptor for nearly all T4SSs. Here, we report that chimeric T4CPs mediate transfer of effector proteins through theEscherichia colipKM101-encoded conjugation system. Studies with these repurposed conjugation systems established a role for acidic C-terminal domains of T4CPs in regulating substrate translocation. Our findings advance a mechanistic understanding of T4CP receptor activity and, further, support a model in which T4SS channels function as passive conduits for any DNA or protein substrates that successfully engage with and pass through the T4CP specificity checkpoint.
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Jansson, Elina, Johanna Lyytikäinen, Panu Tanninen, Kim Eiroma, Ville Leminen, Kirsi Immonen e Liisa Hakola. "Suitability of Paper-Based Substrates for Printed Electronics". Materials 15, n. 3 (26 gennaio 2022): 957. http://dx.doi.org/10.3390/ma15030957.
Abstract (sommario):
Flexible plastic substrates are widely used in printed electronics; however, they cause major climate impacts and pose sustainability challenges. In recent years, paper-based electronics has been studied to increase the recyclability and sustainability of printed electronics. The aim of this paper is to analyze the printability and performance of metal conductor layers on different paper-based substrates using both flexography and screen printing and to compare the achieved performance with that of plastic foils. In addition, the re-pulpability potential of the used paper-based substrates is evaluated. As compared to the common polyethylene terephthalate (PET) substrate, the layer conductivity on paper-based substrates was found to be improved with both the printing methods without having a large influence on the detail rendering. This means that a certain surface roughness and porosity is needed for the improved ink transfer and optimum ink behavior on the surface of the substrate. In the case of uncoated paper-based substrates, the conductivity and print quality decreased by preventing the formation of the proper and intimate ink-substrate contact during the ink transfer. Finally, the re-pulpability trials together with layer quality analysis detected very good, coated substrate candidates for paper-based printed electronics competing with or even outperforming the print quality on the reference PET foil.
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Lim, Jaemook, Youngchan Kim, Jaeho Shin, Younggeun Lee, Wooseop Shin, Weihao Qu, Eunseung Hwang, Seongje Park e Sukjoon Hong. "Continuous-Wave Laser-Induced Transfer of Metal Nanoparticles to Arbitrary Polymer Substrates". Nanomaterials 10, n. 4 (7 aprile 2020): 701. http://dx.doi.org/10.3390/nano10040701.
Abstract (sommario):
Laser-induced forward transfer (LIFT) and selective laser sintering (SLS) are two distinct laser processes that can be applied to metal nanoparticle (NP) ink for the fabrication of a conductive layer on various substrates. A pulsed laser and a continuous-wave (CW) laser are utilized respectively in the conventional LIFT and SLS processes; however, in this study, CW laser-induced transfer of the metal NP is proposed to achieve simultaneous sintering and transfer of the metal NP to a wide range of polymer substrates. At the optimum laser parameters, it was shown that a high-quality uniform metal conductor was created on the acceptor substrate while the metal NP was sharply detached from the donor substrate, and we anticipate that such an asymmetric transfer phenomenon is related to the difference in the adhesion strengths. The resultant metal electrode exhibits a low resistivity that is comparable to its bulk counterpart, together with strong adhesion to the target polymer substrate. The versatility of the proposed process in terms of the target substrate and applicable metal NPs brightens its prospects as a facile manufacturing scheme for flexible electronics.
Tesi sul tema "Substrate transfert":
1
Argoud, Maxime. "Mécanismes de collage et de transfert de films monocristallins dans des structures à couches de polymères". Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00848111.
Abstract (sommario):
Les matériaux polymères sont à l'heure actuelle peu considérés dans le vaste domaine des micro et nano technologies. Ils présentent toutefois certaines propriétés remarquables en comparaison des matériaux traditionnels de la microélectronique. Par exemple leur déformabilité et leur légèreté permettent d'envisager des fonctions de supports flexibles pour des composants électroniques. Par ailleurs, ils offrent des solutions d'assemblage de matériaux de diverses natures. Cette étude porte précisément sur ces deux thématiques. En premier lieu, nous avons étudié les mécanismes de collage impliqués dans l'assemblage de substrats de type silicium par une couche de polymère. D'autre part, nous avons proposé des modèles de mécanisme de transfert de films monocristallins sur polymère. Les propriétés mécaniques des matériaux considérés, principalement du silicium monocristallin et des polymères de type vitreux et caoutchoutique, ainsi que leurs épaisseurs, peuvent varier sur plusieurs ordres de grandeur selon la configuration considérée. L'originalité de l'étude est de déterminer et d'aborder des configurations expérimentalement favorables, par des modèles mécaniques simples, élaborés à partir de lois d'échelle. Nous avons proposé, dans un premier temps, ces modèles pour expliquer des résultats liés à des configurations particulières et ainsi démontrer la pertinence de cette approche. Le cœur de notre étude porte sur le transfert de films monocristallins, aussi fins qu'une centaine de nanomètres d'épaisseur, sur polymère par adaptation du procédé Smart-CutTM (transfert par implantation ionique et fracture). En comparaison d'une configuration standard de cette technologie, nous avons notamment étudié l'impact des propriétés mécaniques propres aux polymères (de types vitreux ou caoutchoutique). Les méthodes en loi d'échelle nous ont ainsi permis de proposer des mécanismes de transfert, de l'échelle du nanomètre jusqu'à la fracture macroscopique. Nous avons également exposé un exemple d'application concret par la réalisation d'objets microélectroniques modèles sur et dans un film monocristallin de silicium. La structure, composée d'un film de quelques micromètres d'épaisseur supporté par un polymère, constitue ainsi une structure flexible d'un point de vue mécanique.
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Gorantla, Sandeep, Alicja Bachmatiuk, Jeonghyun Hwang, Hussain A. Alsalman, Kwak Joon Young, Thomas Seyller, Jürgen Eckert, Michael G. Spencer e Mark H. Rümmeli. "A universal transfer route for graphene". Royal Society of Chemistry, 2014. https://tud.qucosa.de/id/qucosa%3A36288.
Abstract (sommario):
Often synthetic graphene requires transfer onto an arbitrary substrate prior to use because the substrate it was originally synthesized on is inappropriate for either electrical measurement or characterization. While a variety of routes have been developed they are substrate dependant and often involve the use of harsh treatments. Here we present a facile and cheap route that can be applied to graphene over any substrate. This universal transfer route is based on a wet chemical reaction producing gaseous species which can intercalate between the substrate and the graphene and thus gently delaminate the two.
3
Zhang, Shuangfeng. "Wide Bandgap Semiconductor Components Integration in a PCB Substrate for the Development of a High Density Power Electronics Converter". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS398/document.
Abstract (sommario):
Les nouveaux composants à semi-conducteur de type grand gap ont été développés pour des applications de conversion de puissance en raison de leurs hautes fréquences de commutation (de centaine kHz à quelques MHz) et pertes faibles. Afin de bien profiter ses avantages, la technologie des circuits imprimés (PCB) est intéressante pour une intégration à haute densité de puissance grâce à sa flexibilité et son faible coût. Cependant, à cause de la mauvaise conductivité thermique du matériau FR-4 utilisé pour le substrat PCB et la haute densité de puissance réalisée, il est primordial de trouver des solutions thermiques pour améliorer les performances thermiques de la structure de PCB. Dans cette thèse, trois solutions thermiques pour les structures de PCB ont été proposées, y compris des solutions avec des vias thermiques, de cuivre épais sur le substrat de PCB ainsi que des dispositifs de refroidissement thermoélectrique (TEC). Nos études sont basées sur la modélisation électrothermique et la méthode d’éléments finis en 3D. Tout d’abord, l’optimisation des paramètres des vias (diamètre, épaisseur de placage, surface formée par des vias, la distance entre des vias etc.) a été réalisée pour optimiser l’effet de refroidissement. Ensuite, on constate que les performances thermiques des structures de PCB peuvent être améliorées en utilisant cuivre épais sur le substrat de PCB. Cuivre épais augmente le flux thermique latéral dans la couche de cuivre. Les influences de l’épaisseur de cuivre (35 à 500 µm) ont été étudiées. Cette solution est facile à réaliser et peut être combinée à d’autres solutions de refroidissement. Enfin, le dispositif thermoélectrique comme les modules Peltier est une technologie de refroidissement local. Les influences des paramètres de Peltier (Propriétés du matériau thermoélectrique, nombre d’éléments Peltier, distance entre la source de chaleur et les dispositifs Peltier, etc.) ont été identifiées. Il est démontré que des modules Peltier ont l’application potentielle pour le développement d’intégration de PCB attendu que son active contrôle des températuresThe emerging wide bandgap (WBG) semiconductor devices have been developed for power conversion applications instead of silicon devices due to higher switching frequencies (from few 100 kHz to several MHz) and lower on-state losses resulting in a better efficiency. In order to take full advantage of the WBG components, PCB technology is attractive for high power density integration thanks to its flexibility and low cost. However, due to poor thermal conductivity of the commonly used material Flame Retardant-4 (FR4), efficient thermal solutions are becoming a challenging issue in integrated power boards based on PCB substrates. So it is of the first importance to seek technological means in order to improve the thermal performances. In this thesis, three main thermal management solutions for PCB structures have been investigated including thermal vias, thick copper thickness on the PCB substrate as well as thermoelectric cooling (TEC) devices. Our studies are based on the electro-thermal modeling and 3D finite element (FE) methods. Firstly, optimization of the thermal via parameters (via diameter, via plating thickness, via-cluster surface, via pattern, pitch distance between vias etc.) has been realized to improve their cooing performances. We presented and evaluated thermal performances of the PCB structures by analyzing the thermal resistance of the PCB substrate with different thermal vias. Secondly, it is found that thermal performances of the PCB structures can be enhanced by using thick copper thickness on top of the PCB substrate, which increases the lateral heat flux along the copper layer. Influences of the copper thickness (35 µm to 500 µm) has been discussed. This solution is easy to realize and can be combined with other cooling solutions. Thirdly, thermoelectric cooler like Peltier device is a solid-state cooling technology that can meet the local cooling requirements. Influences of Peltier parameters (Thermoelectric material properties, number of Peltier elements, distance between the heating source and the Peltier devices etc.) have been identified. All these analyses demonstrate the potential application of Peltier devices placed beside the heating source for PCB structures, which is a benefit for developing the embedding technology in such structures
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Kambhampati, Patanjali. "Adsorbate-substrate charge transfer excited states /". Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
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Danyal, Karamatullah. "Electron Transfer and Substrate Reduction in Nitrogenase". DigitalCommons@USU, 2014. https://digitalcommons.usu.edu/etd/2181.
Abstract (sommario):
Population growth over the past ~50 years accompanied by the changes in dietary habits due to economic growth have markedly increased the demand for fixed nitrogen. Aided by biological nitrogen fixation, the Haber-Bosch process has been able to fulfill these demands. However, due to its high temperature and pressure requirements, Haber-Bosch is an expensive process. Every year, approximately 2% of the total energy expenditure by man is used to manufacture fixed nitrogen. Biological systems, on the other hand, produce ammonia at ambient temperature and pressure with much higher efficiency than the Haber-Bosch process. Research in the field of biological nitrogen fixation could prove valuable in understanding the mechanism of the enzyme responsible, nitrogenase. This could eventually allow researchers to mimic the enzyme and fix nitrogen at standard temperature and pressure, which would lead to greater availability of fixed nitrogen and a better standard of living for mankind.
As part of this research, nitrogenase of Azotobacter vinelandii was studied to understand the order of events in reduction of substrates and the conformational changes in the enzyme responsible for its ability to reduce said substrates at room temperature and pressure. This knowledge was used to study variant forms of nitrogenase that could be activated using controlled external reductants. This freedom from the biological reductant of nitrogenase opens the door for further research into the understanding and development of enzyme mimics that can reduce substrates at room temperature and pressure.
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Bouillaud, Hugo. "Fabrication et optimisation des caractéristiques thermiques de diodes Schottky de la filière GaAs et reportées sur SiHR pour des applications de multiplication de fréquences". Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILN043.
Abstract (sommario):
Les besoins exponentiels liés aux applications exploitant le domaine THz nécessitent d'accroitre l'éventail des sources disponibles et d'optimiser leur fabrication. Dans ce travail de thèse, nous nous sommes intéressés aux diodes schottky en vue de la réalisation de multiplicateurs de fréquences. Notre travail de recherche expérimental a consisté en l'optimisation des caractéristiques de diodes schottky de filière GaAs, par le développement et la mise en œuvre d'un procédé de fabrication innovant. Dans un premier temps, nous avons réalisé des diodes schottky GaAs sur substrat GaAs de différentes tailles, pour élaborer des composants de référence. Nous avons ensuite fabriqué un composant de type flip-chip pour une application de multiplication à 150 GHz en boitier guide d'ondes. Enfin, dans le but d'améliorer les performances en puissance des diodes, nous avons optimisé leur dissipation thermique en transférant leur structure épitaxiale sur un substrat bénéficiant d'une meilleure conductivité thermique : le SiHR (silicium haute résistivité). Le procédé technologique complet de ces fabrications est détaillé, puis la dernière partie de l'étude est consacrée à leurs caractérisations. D'une part, nous avons évalué les éventuelles variations sur les caractéristiques des diodes GaAs sur GaAs, induites par les différentes tailles. D'autre part nous avons comparé les deux technologies sur les substrats SiHR et GaAs. Ce travail montre l'apport que peut présenter ce type de technologie reportée, où une diminution significative de la résistance thermique des composants est observée, et est associée à un gain notable sur la résistance sérieThe exponential needs associated with applications exploiting the THz domain require to expand the range of available sources and optimize their fabrication processes. In this thesis, we focused on schottky diodes for its use as frequency multipliers. Our experimental research involved optimizing the characteristics of GaAs schottky diodes through the development and implementation of an innovative fabrication process. First, we fabricated GaAs schottky diodes on GaAs substrate with several aspect ratios in order to make a reference in terms of device. Then we fabricated a flip-chip device for a 150 GHz frequency multiplication application in a waveguide block. Finally, in order to enhance the power handling of the diodes, we optimized their thermal dissipation by transferring their epitaxial structure onto a substrate with higher thermal conductivity : SiHR (high resistivity silicon). The complete technological processes for these fabrications are detailed, and the last part of the study is dedicated to their characterization. On one hand, we assessed any variations in the characteristics of GaAs diodes on GaAs induced by the different aspect ratios. On the other hand, we compared the two technologies on SiHR and GaAs substrates. This work demonstrates the potential of this type of transferred technology, where a significant reduction of thermal resistance is observed and is associated with a notable improvement of the series resistance
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Thiam, Ndèye Arame. "Etude et développement de transistors bipolaires à hétérojonctions InP/GaAsSb reportés sur Si en vue de l’amélioration de la dissipation thermique". Thesis, Lille 1, 2012. http://www.theses.fr/2012LIL10168/document.
Abstract (sommario):
Les transistors bipolaires à hétérojonctions (TBH) de la filière InP offrent aujourd’hui des fréquences de coupure supérieures à 400GHz pour le système InP/GaAsSb. Grâce à ces fréquences, les transistors bipolaires sont utilisés pour la réalisation de circuits performants dans des applications millimétriques telle que les communications optiques. Ainsi, pour atteindre ces performances remarquables, les dimensions verticales et latérales des TBH ont été considérablement réduites, entraînant l’auto-échauffement dans les TBHs aux densités de courant élevées. Cette thèse a donc pour objet l’étude et le développement de TBH InP/GaAsSb reportés sur un substrat hôte de silicium en vue de l’amélioration de la dissipation thermique. Une technique de transfert des couches épitaxiales a d’abord été présentée. Nous étudions ensuite les problématiques liées à la technique choisie et les paramètres de report par thermo-compression à basse température ont été optimisés. Le développement de la technologie InP/GaAsSb sur silicium a ensuite été effectué en partant d’une technologie classique de TBH non reportés. La réalisation du contact de collecteur, notamment, a fait l’objet d’une attention particulière. La réduction de l’épaisseur des couches actives ainsi que la technologie employée ont permis d’atteindre une fréquence de transition Ft supérieure à 400GHz. L’étude du comportement thermique des TBH a enfin été présentée grâce à l’extraction de la résistance thermique. Des valeurs très faibles ont été obtenues sur la technologie reportée de 800 à 1300W/K.m selon les dimensions des transistors ; ces valeurs sont très proches de celles simulées pour la même technologie. Elles constituent les premières mesures effectuées sur des TBH InP/GaAsSb transférés sur un substrat de silicium à haute conductivité thermique. Le report des TBHs sur silicium a ainsi permis une amélioration de la résistance thermique de 70% par rapport à une technologie standard de TBH non reportés. Ces résultats permettent de conclure quant à l’efficacité du report pour la réduction drastique de l’auto-échauffement dans les transistors bipolairesThe InP heterojonctions bipolar transistors (HBT) offer today cut-off frequencies larger than 400GHz for the InP / GaAsSb system. Thanks to these performances, these transistors are used for the realization of successful circuits in millimeter-wave applications such as the optical communications. So, to reach these remarkable performances, the HBT are subject to a notorious self-heating phenomenon due to high current density of collector. This thesis thus has for object the study and the development of InP / GaAsSb HBT transferred on a host substrate of silicon with the aim of the improvement of the thermal behavior. We report first of all the principles of the bipolar transistor as well as the state of the art of the various materials used for fast transistors. A transfer technique of epitaxial layers was then presented. We study bounding problems resulting from the chosen technique and transfer parameters for valid thermo-compression at low temperature were optimized. The development of InP / GaAsSb transferred technology on silicon was then made. In particular, the collector contact realization has needed particular attention. Active layers thickness reduction as well as device fabrication process technology allowed reaching transition frequency Ft higher than 400GHz. The study of HBT thermal behavior was finally presented with thermal resistance extraction. Very low values were obtained on the transferred technology, from 800 to1300 W/K.m according to transistors size; these values are very close to those obtained by TCAD simulation for such a technology. It is the first measurement on InP / GaAsSb transferred-HBT on high thermal conductivity silicon substrate. This transfer technology has so allowed thermal resistance improvement of 70 % compared with that of standard HBT technology. This work leads to the influence of transferred-substrate for the severe reduction of self-heating in bipolar transistors technology
8
De, vecchy Jon. "Réalisation de substrats innovants à partir de diamant". Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALT022.
Abstract (sommario):
Au sein d'un objectif global de réduction de la consommation énergétique, les composants de microélectronique se doivent d'être plus performants tout en étant moins énergivores. L'électronique de puissance, dont la fonction est la conversion de l'énergie électrique, est particulièrement concernée puisque ses composants doivent fonctionner à haute intensité, tension et température. Dans ces conditions, le silicium qui les constitue atteint ses limites et la conception de composants faits de matériaux plus adaptés est en plein essor. Parmi les matériaux candidats, le diamant et ses propriétés hors du commun est particulièrement étudié. Son excellente conductivité thermique (2200 W/m/K) combinée à son très fort champ de claquage (10 MV/cm) et à la grande mobilité des trous (2000 cm²/V/s) sont promesses de composants plus petits et plus performants.Cependant, les méthodes de synthèse limitent la taille des substrats de diamant monocristallin à environ 15 x 15 mm² et empêchent encore son industrialisation. L'approche développée dans cette thèse est le report de film de diamant sur un autre substrat en adaptant le procédé Smart Cut^TM. Ce procédé repose sur la combinaison d'une implantation ionique et d'un collage du substrat implanté sur un substrat receveur. Un recuit permet la fracture du substrat implanté et le détachement d'un film d'épaisseur contrôlée qui se retrouve reporté sur le substrat receveur. Cette approche permettrait de réduire les coûts du composant en diminuant la consommation de diamant tout en ouvrant la voie à l'industrialisation grâce à des reports successifs sur substrat grand format.Le Smart Cut^TM doit être intégralement adapté au cas du diamant, des études de chaque brique technologique seront donc présentées. L'obtention de bulles à la surface du substrat implanté après recuit traduit l'adaptation des conditions d'implantation. Le procédé de bullage par plusieurs combinaisons d'implantation ionique d'hydrogène et de recuit sera donc d'abord présenté. Les transformations du diamant durant le procédé seront caractérisées. Des essais complets de transfert en utilisant du collage seront ensuite présentés. Enfin, des perspectives d'optimisation et de réalisation seront donnéesWithin a global aim of reducing energy consumption, microelectronics components must be more efficient and less energy-consuming. Power electronics, which converts electric power, is particularly concerned because its component must operate at high intensity, voltage and temperature. Silicon, the base material of these components, is reaching its limits and the conception of components made with other materials is currently being studied. Among the candidate materials, diamond and its outstanding properties is of great interest. Its excellent thermal conductivity (2200 W/m/K) combined with high breakdown field (10 MV/cm) and high hole mobility (2000 cm²/V/s) are attractive for making smaller and more efficient components.However, monocrystalline diamond synthesis methods are limiting substrate size to about 15 x 15 mm², thus preventing its industrialization. The approach developed in this thesis is the diamond layer transfer to another substrate by adapting the Smart Cut^TM process. This process is based on a combination of ion implantation and bonding of the implanted substrate to a receiving substrate. Annealing then causes the fracture of the implanted substrate and the detachment of a film (with controlled thickness) which is transferred to the receiving substrate. This approach would make it possible to reduce component cost by decreasing diamond consumption and to open the way to industrialization thanks to successive transfers on a large substrate.Smart Cut^TM must be fully adapted to the diamond case, studies of each step will thus be presented. Blistering observation on the implanted substrate surface after annealing is the very first step of ion implantation parameters adaptation. A blistering process using combinations of hydrogen ion implantation and annealing will be presented.Diamond transformations occurring during the process will be characterized. Full layer transfer studies using substrate bonding will then be presented. Finally, prospects for optimization and realization will be given
9
Carlmark, Anna. "Atom transfer radical polymerization from multifunctional substrates". Licentiate thesis, KTH, Polymer Technology, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1447.
Abstract (sommario):
Atom transfer radical polymerization (ATRP) has proven to be a powerful technique to obtain polymers with narrow polydispersities and controlled molecular weight. It also offers control over chain-ends. The technique is the most studied and utilized of thecontrolled/”living” radical polymerization techniques since a large number of monomerscan be polymerized under simple conditions. ATRP can be used to obtain polymer graftsfrom multifunctional substrates. The substrates can be either soluble (i. e. based ondendritic molecules) or insoluble (such as gold or silicon surfaces). The large number ofgrowing chains from the multifunctional substrates increases the probability of inter-and intramolecular reactions. In order to control these kinds of polymerizing systems, andsuppress side-reactions such as termination, the concentration of propagating radicalsmust be kept low. To elaborate such a system a soluble multifunctional substrate, based on 3-ethyl-3-(hydroxymethyl)oxetane, was synthesized. It was used as a macroinitiatorfor the atom transfer radical polymerisation of methyl acrylate (MA) mediated byCu(I)Br and tris(2-(dimethylamino)ethyl)amine (Me6-TREN) in ethyl acetate at room temperature. This yielded a co-polymer with a dendritic-linear architecture. Since mostsolid substrates are sensitive to the temperatures at which most ATRP polymerisations are performed, lowering the polymerization temperatures are preferred. ATRP at ambienttemperature is always more desirable since it also suppresses the formation of thermally formed polymer. The macroinitiator contained approximately 25 initiating sites, which well mimicked the conditions on a solid substrate. The polymers had low polydispersity and conversions as high as 65% were reached without loss of control. The solid substrateof choice was cellulose fibers that prior to this study not had been grafted through ATRP.As cellulose fibers a filter paper, Whatman 1, was used due to its high cellulose content.The hydroxyl groups on the surface was first reacted with 2-bromoisobutyryl bromidefollowed by grafting of MA. Essentially the same reaction conditions were used that hadbeen elaborated from the soluble substrate. The grafting yielded fibers that were very hydrophobic (contact angles>100°). By altering the sacrificial initiator-to-monomer ratiothe amount of polymer that was attached to the surface could be tailor. PMA with degreesof polymerization (DP’s) of 100, 200 and 300 were aimed. In order to control that thepolymerizations from the surface was indeed “living” a second layer of a hydrophilicmonomer, 2-hydroxymethyl methacrylate (HEMA), was grafted onto the surface. Thisdramatically changed the hydrophobic behavior of the fibers.
QC 20100524
10
Voisin, Jérémy. "Influence des pratiques de recharge des aquifères par des eaux pluviales sur les communautés microbiennes des nappes phréatiques". Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1113/document.
Abstract (sommario):
En ville, les systèmes de récupération et d'infiltration des eaux pluviales dans le sous-sol ont pour conséquence d'augmenter la connectivité hydrologique entre la surface et la nappe phréatique. Ces pratiques d'infiltration produisent de nombreuses perturbations physico-chimiques au niveau de la nappe (ex. augmentation des variations thermiques, baisse des concentrations en oxygène dissous, enrichissement de la nappe en matière organique dissoute) mais les conséquences sur le compartiment microbien restent peu connues. L'objectif principal de la thèse est de déterminer les effets de l'infiltration des eaux pluviales sur les communautés microbiennes des nappes phréatiques, aussi bien en termes d'abondance, d'activités que de diversité génétique bactérienne. En se basant sur les changements environnementaux associés à l'infiltration des eaux pluviales et l'analyse des communautés bactériennes, un objectif fondamental est d'évaluer l'importance des phénomènes de dispersion (ex. transferts) et de sélection par des facteurs abiotiques (ex. disponibilité des ressources nutritives) sur les assemblages bactériens au sein des nappes phréatiques. Ces travaux ont été axés sur des expérimentations de terrain utilisant deux approches d'échantillonnage : une méthode active (prélèvements d'eau) et une méthode passive (incubation de substrats artificiels). La description des communautés a été effectuée par une méthode de séquençage de nouvelle génération (i.e. Illumina MiSeq) en se basant sur le gène rrs. Les résultats de ce travail mettent en avant une influence significative des pratiques d'infiltration sur les bactériomes d'un aquifère. En effet, le développement, les activités et la diversité des micro-organismes retrouvés dans la nappe ont été stimulés significativement par l'enrichissement en carbone organique dissous biodégradable engendré par ces pratiques. Néanmoins, cet impact est fortement réduit dans les systèmes étudiés où la zone non saturée est épaisse (> 10 m) et agit comme un filtre physique, chimique et biologique efficace entre le bassin d'infiltration et l'aquifère. Les faibles similarités entre les structures génétiques des bactériomes des eaux d'infiltration et dans la nappe indiquent que la zone non saturée joue un rôle efficace sur la rétention des bactéries dans les systèmes étudiés. En conclusion, cette thèse constitue la première étude d'envergure visant à quantifier la réponse du compartiment microbien des aquifères à des perturbations engendrées par l'infiltration des eaux pluviales en milieu urbain. Elle ouvre aussi de nouvelles perspectives sur les méthodes et outils d'évaluation de la qualité des nappes phréatiquesIn urban area, managed aquifer recharge (MAR) systems raises hydrological connectivity between surface and groundwater. These infiltration practices are the cause of many disturbances in groundwaters (e.g. increase of thermal variations, decrease of dissolved oxygen or enrichment in organic matter) but associated consequences on microbial compartment remains unclear. The main aim of the thesis is to determine the effects of stormwater runoff infiltration on microbial communities of groundwater, in terms of abundance, activities and bacterial diversity. Based on environmental changes associated to MAR practices and bacterial community analyses, a fundamental question is to assess the importance of dispersal (e.g. transfers) and selection by abiotic factors (e.g. nutrients availability) on groundwater communities assemblage. This study is based on field experiments with two complementary strategies of sampling: an active one (i.e. groundwater sampling) and a passive one (incubation of artificial substrate). Communities’ description was made by next-generation sequencing (i.e. Illumina MiSeq) of rrs gene. The results showed a significant influence of MAR practices on microbial communities. Growth, activities and diversity of groundwater micro-organisms were mainly stimulated by biodegradable dissolved organic carbon enrichment associated to MAR practices. Nonetheless, this impact was reduced in systems where the vadose zone is thick (> 10 m) and acts as a physical, chemical and biological filter between the infiltration basin and the aquifer. Low similarities between bacterial communities of infiltration waters and bacterial communities of groundwaters reveal that vadose zone is effective on the retention of bacteria in studied systems. To conclude, this thesis constitutes the first major study that aimed to quantify microbial compartment response to disturbances caused by MAR practices in urban area. It also opens new perspectives on assessment tool for groundwater quality
Libri sul tema "Substrate transfert":
1
Hammer, Ronald E. Charge-transfer photodissociation of HCI and HI on a Ag(111) substrate. Ottawa: National Library of Canada, 1990.
2
Forneiro, Reyes Estévez. Substratum transfer in hiberno-english and code-switching in galaico-spanish. Dublin: University College Dublin, 1996.
3
Zhiming, Bao. The Systemic Nature of Substratum Transfer. A cura di Markku Filppula, Juhani Klemola e Devyani Sharma. Oxford University Press, 2014. http://dx.doi.org/10.1093/oxfordhb/9780199777716.013.024.
Abstract (sommario):
This chapter discusses four grammatical systems in Singapore English that are transferred from Chinese: aspect, pragmatic particles, topicalization, and quantification. Proper analysis of the relevant substrate features reveals extensive clustering: features which form a grammatical system transfer together. Substratum transfer targets the grammatical system, and the transferred system is then exponenced with suitable morphosyntactic materials from the lexifier, filtering out those component features for which the lexifier has no well-formed morphosyntactic exponent. The analysis of the four systems shows that post-transfer stabilization is subject to the normative effect of English. It is argued that data obtained through introspection and corpora are complementary, and substrate-induced grammatical change is best accounted for in a usage-based model that uses the two types of data.
4
Chanon, Michel, e Marye Anne Fox. Photoinduced Electron Transfer: Part C Photoinduced Electron Transfer Reactions : Organic Substrates (Photoinduced Electron Transfer). Elsevier Science Publishing Company, 1988.
5
Fox, Marye Anne. Photoinduced Electron Transfer Part D: Photoinduced Electron Transfer Reactions : Inorganic Substrates and Applications. Elsevier Science Ltd, 1988.
6
Uffmann, Christian. World Englishes and Phonological Theory. A cura di Markku Filppula, Juhani Klemola e Devyani Sharma. Oxford University Press, 2015. http://dx.doi.org/10.1093/oxfordhb/9780199777716.013.32.
Abstract (sommario):
The relationship between phonological theory and World Englishes is generally characterized by a mutual lack of interest. This chapter argues for a greater engagement of both fields with each other, looking at constraint-based theories of phonology, especially Optimality Theory (OT), as a case in point. Contact varieties of English provide strong evidence for synchronically active constraints, as it is substrate or L1 constraints that are regularly transferred to the contact variety, not rules. Additionally, contact varieties that have properties that are in some way ‘in between’ the substrate and superstrate systems provide evidence for constraint hierarchies or implicational relationships between constraints, illustrated here primarily with examples from syllable structure. Conversely, for a scholar working on the description of World Englishes, OT can offer an explanation of where the patterns found in a contact variety come from, namely from the transfer of substrate constraint rankings (and subsequent gradual constraint demotion).
7
Wiltshire, Caroline R. Emergence of the Unmarked in Indian Englishes with Different Substrates. A cura di Markku Filppula, Juhani Klemola e Devyani Sharma. Oxford University Press, 2014. http://dx.doi.org/10.1093/oxfordhb/9780199777716.013.007.
Abstract (sommario):
This study uses data from Indian English as a second language, spoken by speakers of five first languages, to illustrate and evaluate the role of the emergence of the unmarked (TETU) in phonological theory. The analysis focusses on word-final consonant devoicing and cluster reduction, for which the five Indian first languages have various constraints, while Indian English is relatively unrestricted. Variation in L2 Indian Englishes results from both transfer of L1 phonotactics and the emergence of the unmarked, accounted for within Optimality Theory. The use of a learning algorithm also allows us to test the relative importance of markedness and frequency and to evaluate the relative markedness of various clusters. Thus, data from Indian Englishes provides insight into the form and function of markedness constraints, as well as the mechanisms of Second Language Acquisition (SLA).
Capitoli di libri sul tema "Substrate transfert":
1
Zhang, Q., C. Zheng, K. Sagoe-Crentsil e W. Duan. "Transfer and Substrate Effects on 2D Materials for Their Sensing and Energy Applications in Civil Engineering". In Lecture Notes in Civil Engineering, 409–19. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-3330-3_42.
Abstract (sommario):
AbstractThe recent emergence of two-dimensional (2D) materials such as graphene and transition metal dichalcogenides (TMDs) of the family (Mo, W)(S, Se)2 has attracted interest from a broad range of engineering applications, including advanced sensing and energy harvesting and conservation, because of their distinctive properties. However, it is critical important to achieve intact delamination and transfer of these atomically thin materials, as well as to understand the effects of the target substrates on their optical and electronic properties. Therefore, we developed and compared techniques for transferring as-grown WS2 crystals to arbitrary substrates. Polystyrene-assisted wet transfer can realize improved preservation of monolayer WS2 crystals than the commonly used poly(methyl methacrylate) (PMMA)-assisted wet transfer method, due to minimal chemical etching involved in the 2D material delamination process. The intercalation of alkali ions in the PMMA-based transfer method induces chemical doping over the transferred 2D crystals, leading to the formation of trions. Moreover, the edges of the crystals on hydrophilic substrates, such as sapphire or SiO2/Si, are subject to ambient water intercalation, which locally affects the photoluminescence behavior of the monolayer WS2 by doping and changing of the dielectric environment. This non-uniform optical behavior is absent when the crystal is transferred onto a hydrophobic substrate through which ambient water cannot penetrate. These results have important implications for the choice of target substrate and transfer method adopted for 2D TMD-based applications such as next-generation strain sensing, photodetectors, gas sensing, bio sensing, solar energy harvesting and radiative cooling in which uniform behavior of the channel material is required.
2
Liu, Ai Qun. "Substrate Transfer Process". In RF MEMS Switches and Integrated Switching Circuits, 207–27. Boston, MA: Springer US, 2010. http://dx.doi.org/10.1007/978-0-387-46262-2_9.
3
Hussain, Aftab M. "Substrates, Transfer, and Bonding". In Introduction to Flexible Electronics, 134–52. Boca Raton: CRC Press, 2021. http://dx.doi.org/10.1201/9781003010715-12.
4
Kubyshkina, Veronika, Khellil Sefiane, Daniel Orejon e Coinneach Mackenzie Dover. "Droplet Interplay on Microdecorated Substrates". In Advances in Heat Transfer and Thermal Engineering, 79–82. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-33-4765-6_14.
5
Manokruang, Supasit, Frederic Vignat, Matthieu Museau e Maxime Limousin. "Process Parameters Effect on Weld Beads Geometry Deposited by Wire and Arc Additive Manufacturing (WAAM)". In Lecture Notes in Mechanical Engineering, 9–14. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-70566-4_3.
Abstract (sommario):
AbstractAmong Additive Manufacturing technologies, Wire and Arc Additive Manufacturing process is strongly dependent of deposition conditions such as welding parameters, substrate temperature, trajectory. In this research, geometry and temperature evolutions of single beads have been investigated according to process parameters modifications. For our experiment, a heating device have been used in order to control the substrate temperature from room temperature up to 400 °C. Considering the Cold Metal Transfer technology, welding parameters, Wire Feed Speed (WFS) and Travel Speed (TS), have been modified while keeping a constant ratio λ (WFS/TS). Results indicate that weld bead geometry, height (h) and width (w), is influenced by substrate temperature and welding parameters. It has been shown that substrate temperature, itself influenced by process parameters, tends to produce thicker and lower weld beads while it increases.
6
Alvarez-Gonzalez, Rafael, Joel Moss, Claude Niedergang e Felix R. Althaus. "In Vitro ADP-Ribosylation Utilizing 2′Deoxy-NAD+ as a Substrate". In ADP-Ribose Transfer Reactions, 53–56. New York, NY: Springer US, 1989. http://dx.doi.org/10.1007/978-1-4615-8507-7_9.
7
Wang, Xin, Zeyu Liu, Li Wang e Yuying Yan. "Investigation of Droplet Evaporation on Copper Substrate with Different Roughness". In Advances in Heat Transfer and Thermal Engineering, 225–28. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-33-4765-6_41.
8
Ui, Michio. "GTP-binding Proteins, Substrates of Pertussis Toxin-Catalyzed ADP-Ribosylation, as Mediators of Receptor-Coupled Signal Transduction". In ADP-Ribose Transfer Reactions, 414–21. New York, NY: Springer US, 1989. http://dx.doi.org/10.1007/978-1-4615-8507-7_79.
9
Knoll, Wolfgang, Natascha Bunjes, Morgan Denyer, Claudia Heibel, Mieko Matsuzawa, Renate Naumann, Andreas Offenhäusser et al. "Preparation, Structural Characterization and Functional Coupling of Tethered Membranes to Solid Substrates". In Biophysics of Electron Transfer and Molecular Bioelectronics, 67–89. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4757-9516-5_4.
10
Poulter, C. Dale. "Mechanistic Studies of the Prenyl Transfer Reaction with Fluorinated Substrate Analogs". In ACS Symposium Series, 158–68. Washington, DC: American Chemical Society, 1996. http://dx.doi.org/10.1021/bk-1996-0639.ch012.
Atti di convegni sul tema "Substrate transfert":
1
Wei, G., H. Zhang, L. Li e X. Y. Wang. "Numerical and Experimental Studies of Substrate Melting During Thermal Spraying". In ASME 2003 Heat Transfer Summer Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/ht2003-47154.
Abstract (sommario):
Melting and re-solidification of the substrate plays an important role in thermal spray coating. A good understanding of this phenomenon will help us to achieve better bonding. A numerical model is developed to investigate the solidification of the droplet, and melting and re-solidification of the substrate. The solidification interface movement is obtained by applying a rapid solidification model on the solid/melt interface. Numerical simulations have been used to study the influence of materials and temperatures of the splat and substrate on substrate melting and re-solidification. In the corresponding experiments, the molybdenum powder is sprayed onto a stainless steel, brass (70%Cu) or aluminum substrate by atmospheric plasma spraying system. The crater depth of the substrates has been measured. Experimental results show that the material properties of the splat and substrate and melting temperature of the substrate play important roles on substrate melting and maximum melting depth. A dimensionless parameter, temperature factor, has been proposed from analysis and can be used as an indicator whether a substrate melting will occur for a certain combination of the droplet and substrate, and this parameter can be correlated with the maximum melting depth of the substrate.
2
Kwok, King Hong, e Wilson K. S. Chiu. "Laser-Induced Chemical Vapor Deposition on Moving Glass Rods". In ASME 2003 Heat Transfer Summer Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/ht2003-47446.
Abstract (sommario):
The feasibility of using pyrolytic Laser-Induced Chemical Vapor Deposition (LCVD) to deposit carbon coatings on moving fused quartz rods have been investigated in this study. This LCVD system uses a CO2 laser to locally heat substrates in open air to create a hot spot. Pyrolysis of hydrocarbon species occurs and subsequently deposits a layer of carbon film onto the substrate surface. The results of this study indicate that the deposition rate of carbon film increases exponentially within the range of laser power, while an increase in traverse velocity of the substrate will also increase the deposition rate until a maximum deposition rate is reached, and further increases in the traverse velocity will decrease the deposition rate. We suspect that this optimal deposition rate is caused by substrate motion, which affects the substrate surface temperature, and consequently the effective surface area available for film deposition.
3
Dhiman, Rajeev, e Sanjeev Chandra. "Effect of Substrate Temperature on Splashing of Molten Metal Droplets". In ASME 2004 Heat Transfer/Fluids Engineering Summer Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ht-fed2004-56096.
Abstract (sommario):
The effect of substrate temperature on the splashing of molten metal droplets was studied experimentally. Uniform-size molten tin droplets (550 μm diameter) were produced using a drop-on-demand generator. To achieve high impact velocities substrates were mounted on the rim of a rotating flywheel and heated using cartridge heaters to vary substrate temperature. Droplets hitting a smooth cold substrate splashed extensively producing many small satellite droplets and leaving on the surface a small, irregular splat with many fingers projecting from its periphery. Droplets hitting a hot substrate did not splash but spread out to form a smooth disc. A new splashing criterion was developed to calculate the substrate temperature at which this transition occurred. It assumes splashing to occur when the solid layer produced as a result of droplet solidification grows equal to the splat thickness and obstructs the spreading liquid.
4
Chung, Jaewon, Seunghwan Ko, Costas P. Grigoropoulos, Nicole R. Bieri, Cedric Dockendorf e Dimos Poulikakos. "Microconductors on Polymer by Nanoink Printing and Pulsed Laser Curing". In ASME 2004 Heat Transfer/Fluids Engineering Summer Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ht-fed2004-56702.
Abstract (sommario):
In this study, pulsed laser based curing of a printed nanoink (nanoparticle ink) combined with moderate and controlled substrate heating was investigated to create microconductors at low enough temperatures appropriate for polymeric substrates. The present work relies on (1) melting temperature depression of nanoparticles smaller than a critical size, (2) DOD (drop on demand) jettability of nanoparticle ink and (3) small heat affected zone of pulsed laser heating. In the experiment, gold nanoparticles of 3–7nm diameter dissolved in toluene solvent was used as ink. This nanoink was printed on a polymeric substrate which was heated to evaporate the solvent during or after printing. The overall morphology of the gold microline was determined during the printing process and was controlled by changing the substrate temperature during jetting. By employing a micro-second pulsed laser, the nanoparticles were melted and coalesced at a low temperature to form a conductive microline which has 4–5 times higher resistivity than the bulk value without damaging the temperature sensitive polymeric substrate.
5
Rao, P. Sharath C., e Muhammad M. Rahman. "Analysis of Steady State Conjugate Heat Transfer in a Circular Microtube Inside a Substrate". In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-59921.
Abstract (sommario):
The steady state heat transfer for laminar flow inside a circular microtube within a rectangular substrate has been investigated. Silicon, Silicon Carbide, and Stainless Steel were the substrates used and Water and FC-72 were the coolants employed. Equations governing the conservation of mass, momentum, and energy were solved in the fluid region. Within the solid wafer, the heat conduction was solved. A thorough investigation for velocity and temperature distributions for different substrates and coolants was performed by varying geometrical dimensions and Reynolds number. At a constant diameter and Reynolds number, for combinations comprising same coolant but different substrates, one with the lowest solid to fluid thermal conductivity ratio (ks/kf) attains the highest local peripheral average interface temperature. It was found that the Nusselt number is more for a system with Silicon as the substrate and FC-72 as the working fluid and the least for a system with Stainless Steel as the substrate and Water as the working fluid. The lower ks/kf ratio of Stainless Steel-Water combination is the main reason for the lower Nusselt number. With the increase in hydraulic diameter and Reynolds number, the average Nusselt number increased. It was also observed that the maximum temperature of the substrate and hence the outlet temperature of the fluid increased as the Reynolds number decreased.
6
Li, De-Jun, Murat U. Guruz e Yip-Wah Chung. "Ultrathin CNx Overcoats for 1 Tb/in2 Hard Disk Drive Systems". In STLE/ASME 2001 International Joint Tribology Conference. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/trib-nano2001-108.
Abstract (sommario):
Abstract Carbon nitride films were grown on silicon and hard disk substrates using pulsed dc magnetron sputtering in a single cathode deposition system. Substrates were mounted on a specially designed rotating holder that allowed 45° tilt angle and substrate rotation about the surface normal up to 20 rpm. AFM scans over 10×10 μm2 showed that 50 nm thick CNx films prepared under optimum substrate bias conditions have r.m.s. surface roughness almost four times lower than those prepared without substrate tilt and rotation. We observed a two-fold reduction in corrosion damage for hard disk substrates with 1 nm CNx overcoats deposited with substrate tilt and rotation. This improved performance is likely a result of more efficient and uniform momentum transfer parallel to the surface during deposition in this configuration.
7
Yi-Yan, A., W. K. Chan, T. J. Gmitter e M. Seto. "Semiconductor-grafted integrated optics". In Integrated Photonics Research. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/ipr.1990.mi1.
Abstract (sommario):
Epitaxial lift-off can be effectively used to transfer thin-film semiconductor layers from their parent substrate to foreign substrates that are not necessarily made of semiconductor material.1 The transferred films are bonded, without glue, to the target substrate by van der Waals forces. The potential of this technique is greatly enhanced by grafting semiconductor layers directly onto substrates with optical waveguide circuits and, additionally, by establishing optical interaction between the two.
8
Al-okaily, Ala’a, e Placid Ferreira. "Characterization of Delamination in Laser Micro Transfer Printing". In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64668.
Abstract (sommario):
Micro transfer printing is rapidly emerging as an effective method for heterogeneous materials integration. It transfers prefabricated micro- and nanoscale structures referred to as ‘inks’, from growth or fabrication donor substrates to functional receiver substrates. Laser Micro Transfer Printing (LMTP) is a laser-driven version of the micro transfer printing process, developed at the University of Illinois to enable non-contact release of the microstructure, thus making the transfer printing process independent of the properties or preparation of the receiving substrate. In this paper, an extensive study is conducted to investigate the capability of the LMTP process. Using square shaped silicon inks and polydimethylsiloxane (PDMS) stamps, and varying the lateral dimensions and thickness of the ink, the power absorption by the ink is measured to estimate the total energy stored in the ink-stamp system to initiate and propagate delamination at the interface. The delamination time for each size and thickness is experimentally observed at different laser beam powers using a high speed camera. Further, an axisymmetric thermo-mechanical FEM is developed to estimate the delamination temperatures at the interface utilizing the delamination time and power absorption for different ink sizes and thickness.
9
Jiang, X. Y., Y. P. Wan, X. Y. Wang, H. Zhang, R. Goswami, H. Herman e S. Sampath. "Investigation of Splat/Substrate Contact During Molybdenum Thermal Spraying". In ITSC 2000, a cura di Christopher C. Berndt. ASM International, 2000. http://dx.doi.org/10.31399/asm.cp.itsc2000p0729.
Abstract (sommario):
Abstract Molybdenum splats were produced at three plasma conditions on steel substrates preheated to three temperatures. Morphology of splats and corresponding craters formed on substrates were observed; dimensions of splats and craters were measured with an optical non-contact interferometer. It is found that substrate is significantly melted and deformed upon impact of the droplet, which leads to the formation of flower like splats and craters. On average, only about 36 to 53 % of the areas covered by splats were in good metallurgical/mechanical contact with substrate. Normalized crater volume increases with droplet size and the contact is improved for the high particle energy/high substrate temperature condition as compared with low particle energy/medium substrate energy condition. Splat morphology and crater formation is explained based on impinging jet heat transfer model.
10
Lu, Gui, Yuan-Yuan Duan e Xiao-Dong Wang. "Effects of Free Surface Evaporation on Water Nano-Droplet Wetting Kinetics: A Molecular Dynamics Study". In ASME 2013 4th International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/mnhmt2013-22108.
Abstract (sommario):
The dynamic wetting of water nano-droplet with evaporation on the heated gold substrate was examined using molecular dynamics simulation. Various substrate and droplet pre-heated temperatures were calculated to obtained different evaporating rates. Water molecules attachment-detachment details were traced near the contact line region to show the microscopic details and evidences for the spreading-evaporating droplet. The increasing substrate temperature greatly affected the dynamic wetting process, while the initial temperature of water droplet had very limited effects. The effects of free surface evaporation on wetting kinetics for both hydrophobic and hydrophilic substrates were examined. The radius versus time curves agree well with the Molecular kinetic theory (MKT) for spreading without evaporation and deviate from the MKT for the spreading with evaporation. The enhancement on wetting kinetics due to evaporation can be attributed to the reducing of liquid-vapor surface tension and the strengthening in water molecules transport in contact line region and bulk droplet.
Rapporti di organizzazioni sul tema "Substrate transfert":
1
Elbaum, Michael, e Peter J. Christie. Type IV Secretion System of Agrobacterium tumefaciens: Components and Structures. United States Department of Agriculture, marzo 2013. http://dx.doi.org/10.32747/2013.7699848.bard.
Abstract (sommario):
Objectives: The overall goal of the project was to build an ultrastructural model of the Agrobacterium tumefaciens type IV secretion system (T4SS) based on electron microscopy, genetics, and immunolocalization of its components. There were four original aims: Aim 1: Define the contributions of contact-dependent and -independent plant signals to formation of novel morphological changes at the A. tumefaciens polar membrane. Aim 2: Genetic basis for morphological changes at the A. tumefaciens polar membrane. Aim 3: Immuno-localization of VirB proteins Aim 4: Structural definition of the substrate translocation route. There were no major revisions to the aims, and the work focused on the above questions. Background: Agrobacterium presents a unique example of inter-kingdom gene transfer. The process involves cell to cell transfer of both protein and DNA substrates via a contact-dependent mechanism akin to bacterial conjugation. Transfer is mediated by a T4SS. Intensive study of the Agrobacterium T4SS has made it an archetypal model for the genetics and biochemistry. The channel is assembled from eleven protein components encoded on the B operon in the virulence region of the tumor-inducing plasmid, plus an additional coupling protein, VirD4. During the course of our project two structural studies were published presenting X-ray crystallography and three-dimensional reconstruction from electron microscopy of a core complex of the channel assembled in vitro from homologous proteins of E. coli, representing VirB7, VirB9, and VirB10. Another study was published claiming that the secretion channels in Agrobacterium appear on helical arrays around the membrane perimeter and along the entire length of the bacterium. Helical arrangements in bacterial membranes have since fallen from favor however, and that finding was partially retracted in a second publication. Overall, the localization of the T4SS within the bacterial membranes remains enigmatic in the literature, and we believe that our results from this project make a significant advance. Summary of achievements : We found that polar inflations and other membrane disturbances relate to the activation conditions rather than to virulence protein expression. Activation requires low pH and nutrient-poor medium. These stress conditions are also reflected in DNA condensation to varying degrees. Nonetheless, they must be considered in modeling the T4SS as they represent the relevant conditions for its expression and activity. We identified the T4SS core component VirB7 at native expression levels using state of the art super-resolution light microscopy. This marker of the secretion system was found almost exclusively at the cell poles, and typically one pole. Immuno-electron microscopy identified the protein at the inner membrane, rather than at bridges across the inner and outer membranes. This suggests a rare or transient assembly of the secretion-competent channel, or alternatively a two-step secretion involving an intermediate step in the periplasmic space. We followed the expression of the major secreted effector, VirE2. This is a single-stranded DNA binding protein that forms a capsid around the transferred oligonucleotide, adapting the bacterial conjugation to the eukaryotic host. We found that over-expressed VirE2 forms filamentous complexes in the bacterial cytoplasm that could be observed both by conventional fluorescence microscopy and by correlative electron cryo-tomography. Using a non-retentive mutant we observed secretion of VirE2 from bacterial poles. We labeled the secreted substrates in vivo in order detect their secretion and appearance in the plant cells. However the low transfer efficiency and significant background signal have so far hampered this approach.
2
Alexandrov, Boian. PR-650-174516-R01 Corrosion Resistant Weld Overlays for Pipeline Installations. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), giugno 2021. http://dx.doi.org/10.55274/r0012108.
Abstract (sommario):
Pipeline failure due to corrosion is a common problem in the oil and gas and petrochemical industry. A cost-effective way to prevent these failures is the application of corrosion-resistant weld overlays (WOLs) onto the internal surface of line pipe. A WOL is a deposition of a filler metal - such as a nickel-base alloy - onto the surface of a part - usually carbon or low alloy steels - to introduce desired surface properties to the original substrate [1]. As such, the service life of the substrate is increased which results in reduced costs to industries such as oil and gas and petrochemical as well as to the environment. WOLs are commonly created using arc welding processes such as cold wire and hot wire gas tungsten arc welding (CW-, HW-GTAW), gas metal arc welding (GMAW), and submerged arc welding (SAW). Previous research performed at OSU indicates that a low heat input GMAW process, such as cold metal transfer (CMT), can produce WOLs which corrode up to ten times slower than overlays produced with CW-GTAW [2, 3], with up to four times higher deposition rates [4]. However, the majority of research into WOLs produced with the CMT process has been done with respect to nuclear applications, so there is a need for process optimization directed towards oil and gas applications. This project investigates the potential of CMT as an alternative to HW-GTAW for use with nickel-base alloys 625, 686 and 825 clad onto low alloy steel X65.
3
Prasad, Kuldeep R., e Dale P. Bentz. Thermal performance of fire resistive materials II. A multi-layer one-dimensional heat transfer model for fire resistive materials protecting a substrate. Gaithersburg, MD: National Institute of Standards and Technology, 2008. http://dx.doi.org/10.6028/nist.ir.7482.
4
Glass, R., e L. Hendler. Defect Recognition In Regularly Patterned Substrates Using Optical Fourier Transform Techniques Final Report CRADA No. TSB-1164-95. Office of Scientific and Technical Information (OSTI), marzo 2018. http://dx.doi.org/10.2172/1430944.
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Glass, R. Defect Recognition In Regularly Patterned Substrates Using Optical Fourier Transform Techniques Final Report CRADA No. TSB-1164-95. Office of Scientific and Technical Information (OSTI), dicembre 1996. http://dx.doi.org/10.2172/759917.
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Kurek, Harry, e John Wagner. Development and Demonstration of a High Efficiency, Rapid Heating, Low NOx Alternative to Conventional Heating of Round Steel Shapes, Steel Substrate (Strip) and Coil Box Transfer Bars. Office of Scientific and Technical Information (OSTI), gennaio 2010. http://dx.doi.org/10.2172/970839.
7
Sessa, Guido, e Gregory Martin. MAP kinase cascades activated by SlMAPKKKε and their involvement in tomato resistance to bacterial pathogens. United States Department of Agriculture, gennaio 2012. http://dx.doi.org/10.32747/2012.7699834.bard.
Abstract (sommario):
The research problem: Pseudomonas syringae pv. tomato (Pst) and Xanthomonas campestrispv. vesicatoria (Xcv) are the causal agents of tomato bacterial speck and spot diseases, respectively. These pathogens colonize the aerial parts of the plant and cause economically important losses to tomato yield worldwide. Control of speck and spot diseases by cultural practices or chemicals is not effective and genetic sources of resistance are very limited. In previous research supported by BARD, by gene expression profiling we identified signaling components involved in resistance to Xcvstrains. Follow up experiments revealed that a tomato gene encoding a MAP kinase kinase kinase (MAPKKKe) is required for resistance to Xcvand Pststrains. Goals: Central goal of this research was to investigate the molecular mechanisms by which MAPKKKεand associated MAP kinase cascades regulate host resistance. Specific objectives were to: 1. Determine whether MAPKKKεplays a broad role in defense signaling in plants; 2. Identify components of MAP kinase cascades acting downstream of MAPKKKε; 3. Determine the role of phosphorylation-related events in the function of MAPKKKε; 4. Isolate proteins directly activated by MAPKKKε-associatedMAPK modules. Our main achievements during this research program are in the following major areas: 1. Characterization of MAPKKKεas a positive regulator of cell death and dissection of downstream MAP kinase cascades (Melech-Bonfil et al., 2010; Melech-Bonfil and Sessa, 2011). The MAPKKKεgene was found to be required for tomato resistance to Xcvand Pstbacterial strains and for hypersensitive response cell death triggered by different R gene/effector gene pairs. In addition, overexpression analysis demonstrated that MAPKKKεis a positive regulator of cell death, whose activity depends on an intact kinase catalytic domain. Epistatic experiments delineated a signaling cascade downstream of MAPKKKεand identified SIPKK as a negative regulator of MAPKKKε-mediated cell death. Finally, genes encoding MAP kinase components downstream of MAPKKKεwere shown to contribute to tomato resistance to Xcv. 2. Identification of tomato proteins that interact with MAPKKKεand play a role in plant immunity (Oh et al., 2011). We identified proteins that interact with MAPKKKε. Among them, the 14-3-3 protein TFT7 was required for cell death mediated by several R proteins. In addition, TFT7 interacted with the MAPKK SlMKK2 and formed homodimersin vivo. Thus, TFT7 is proposed to recruit SlMKK2 and MAPKKK client proteins for efficient signal transfer. 3. Development of a chemical genetic approach to identify substrates of MAPKKKε-activated MAP kinase cascades (Salomon et al., 2009, 2011). This approach is based on engineering the kinase of interest to accept unnatural ATP analogs. For its implementation to identify substrates of MAPKKKε-activated MAP kinase modules, we sensitized the tomato MAP kinase SlMPK3 to ATP analogs and verified its ability to use them as phosphodonors. By using the sensitized SlMPK3 and radiolabeled N6(benzyl)ATP it should be possible to tag direct substrates of this kinase. 4. Development of methods to study immunity triggered by pathogen-associated molecular patterns (PAMPs) in tomato and N. benthamiana plants (Kim et al., 2009; Nguyen et al. 2010). We developed protocols for measuring various PTI-associatedphenotypes, including bacterial populations after pretreatment of leaves with PAMPs, induction of reporter genes, callose deposition at the cell wall, activation of MAP kinases, and a luciferase-based reporter system for use in protoplasts. Scientific and agricultural significance: Our research activities discovered and characterized a signal transduction pathway mediating plant immunity to bacterial pathogens. Increased understanding of molecular mechanisms of immunity will allow them to be manipulated by both molecular breeding and genetic engineering to produce plants with enhanced natural defense against disease. In addition, we successfully developed new biochemical and molecular methods that can be implemented in the study of plant immunity and other aspects of plant biology.
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Irudayaraj, Joseph, Ze'ev Schmilovitch, Amos Mizrach, Giora Kritzman e Chitrita DebRoy. Rapid detection of food borne pathogens and non-pathogens in fresh produce using FT-IRS and raman spectroscopy. United States Department of Agriculture, ottobre 2004. http://dx.doi.org/10.32747/2004.7587221.bard.
Abstract (sommario):
Rapid detection of pathogens and hazardous elements in fresh fruits and vegetables after harvest requires the use of advanced sensor technology at each step in the farm-to-consumer or farm-to-processing sequence. Fourier-transform infrared (FTIR) spectroscopy and the complementary Raman spectroscopy, an advanced optical technique based on light scattering will be investigated for rapid and on-site assessment of produce safety. Paving the way toward the development of this innovative methodology, specific original objectives were to (1) identify and distinguish different serotypes of Escherichia coli, Listeria monocytogenes, Salmonella typhimurium, and Bacillus cereus by FTIR and Raman spectroscopy, (2) develop spectroscopic fingerprint patterns and detection methodology for fungi such as Aspergillus, Rhizopus, Fusarium, and Penicillium (3) to validate a universal spectroscopic procedure to detect foodborne pathogens and non-pathogens in food systems. The original objectives proposed were very ambitious hence modifications were necessary to fit with the funding. Elaborate experiments were conducted for sensitivity, additionally, testing a wide range of pathogens (more than selected list proposed) was also necessary to demonstrate the robustness of the instruments, most crucially, algorithms for differentiating a specific organism of interest in mixed cultures was conceptualized and validated, and finally neural network and chemometric models were tested on a variety of applications. Food systems tested were apple juice and buffer systems. Pathogens tested include Enterococcus faecium, Salmonella enteritidis, Salmonella typhimurium, Bacillus cereus, Yersinia enterocolitis, Shigella boydii, Staphylococus aureus, Serratiamarcescens, Pseudomonas vulgaris, Vibrio cholerae, Hafniaalvei, Enterobacter cloacae, Enterobacter aerogenes, E. coli (O103, O55, O121, O30 and O26), Aspergillus niger (NRRL 326) and Fusarium verticilliodes (NRRL 13586), Saccharomyces cerevisiae (ATCC 24859), Lactobacillus casei (ATCC 11443), Erwinia carotovora pv. carotovora and Clavibacter michiganense. Sensitivity of the FTIR detection was 103CFU/ml and a clear differentiation was obtained between the different organisms both at the species as well as at the strain level for the tested pathogens. A very crucial step in the direction of analyzing mixed cultures was taken. The vector based algorithm was able to identify a target pathogen of interest in a mixture of up to three organisms. Efforts will be made to extend this to 10-12 key pathogens. The experience gained was very helpful in laying the foundations for extracting the true fingerprint of a specific pathogen irrespective of the background substrate. This is very crucial especially when experimenting with solid samples as well as complex food matrices. Spectroscopic techniques, especially FTIR and Raman methods are being pursued by agencies such as DARPA and Department of Defense to combat homeland security. Through the BARD US-3296-02 feasibility grant, the foundations for detection, sample handling, and the needed algorithms and models were developed. Successive efforts will be made in transferring the methodology to fruit surfaces and to other complex food matrices which can be accomplished with creative sampling methods and experimentation. Even a marginal success in this direction will result in a very significant breakthrough because FTIR and Raman methods, in spite of their limitations are still one of most rapid and nondestructive methods available. Continued interest and efforts in improving the components as well as the refinement of the procedures is bound to result in a significant breakthrough in sensor technology for food safety and biosecurity.
9
Dick, Warren, Yona Chen e Maurice Watson. Improving nutrient availability in alkaline coal combustion by-products amended with composted animal manures. United States Department of Agriculture, 2002. http://dx.doi.org/10.32747/2002.7587240.bard.
Abstract (sommario):
Hypothesis and Objectives: We hypothesized that coal combustion products (CCPs), including those created during scrubbing of sulfur dioxide from flue gases, can be used alone or mixed with composted animal manures as effective growth media for plants. Our specific objectives were, therefore, to (1) measure the chemical, physical and hydraulic properties of source materials and prepared mixes, (2) determine the optimum design mix of CCPs and composted animal manures for growth of plants, (3) evaluate the leachate water quality and plant uptake of selected elements from prepared mixes, (4) quantify the interaction between composted animal manures and B concentrations in the mixes, (5) study the availability of P to plants growing in the mixes, and (6) determine the microbial community and siderophores involved in the solubilization of Fe and its transfer to plants. Background: In recent years a major expansion of electricity production by coal combustion has taken place in Israel, the United States and the rest of the world. As a result, a large amount of CCPs are created that include bottom ash, fly ash, flue gas desulfurization (FGD) gypsum and other combustion products. In Israel 100,000 tons of fly ash (10% of total CCPs) are produced each year and in the US a total of 123 million tons of CCPs are produced each year with 71 million tons of fly ash, 18 million tons of bottom ash and 12 million tons of FGD gypsum. Many new scrubbers are being installed and will come on-line in the next 2 to 10 years and this will greatly expand the amount of FGD gypsum. One of the main substrates used in Israel for growth media is volcanic ash (scoria; tuff). The resemblance of bottom coal ash to tuff led us to the assumption that it is possible to substitute tuff with bottom ash. Similarly, bottom ash and FGD gypsum were considered excellent materials for creating growth mixes for agricultural and nursery production uses. In the experiments conducted, bottom ash was studied in Israel and bottom ash, fly ash and FGD gypsum was studied in the US. Major Achievements: In the US, mixes were tested that combine bottom ash, organic amendments (i.e. composts) and FGD gypsum and the best mixes supported growth of tomato, wheat and marigolds that were equal to or better than two commercial mixes used as a positive control. Plants grown on bottom ash in Israel also performed very well and microelements and radionuclides analyses conducted on plants grown on bottom coal ash proved it is safe to ingest the edible organs of these plants. According to these findings, approval to use bottom coal ash for growing vegetables and fruits was issued by the Israeli Ministry of Health. Implications: Bottom coal ash is a suitable substitute for volcanic ash (scoria; tuff) obtained from the Golan Heights as a growth medium in Israel. Recycling of bottom coal ash is more environmentally sustainable than mining a nonrenewable resource. The use of mixes containing CCPs was shown feasible for growing plants in the United States and is now being evaluated at a commercial nursery where red sunset maple trees are being grown in a pot-in-pot production system. In addition, because of the large amount of FGD gypsum that will become available, its use for production of agronomic crops is being expanded due to success of this study.
10
Dick, Warren, Yona Chen e Maurice Watson. Improving nutrient availability in alkaline coal combustion by-products amended with composted animal manures. United States Department of Agriculture, dicembre 2006. http://dx.doi.org/10.32747/2006.7695883.bard.
Abstract (sommario):
Hypothesis and Objectives: We hypothesized that coal combustion products (CCPs), including those created during scrubbing of sulfur dioxide from flue gases, can be used alone or mixed with composted animal manures as effective growth media for plants. Our specific objectives were, therefore, to (1) measure the chemical, physical and hydraulic properties of source materials and prepared mixes, (2) determine the optimum design mix of CCPs and composted animal manures for growth of plants, (3) evaluate the leachate water quality and plant uptake of selected elements from prepared mixes, (4) quantify the interaction between composted animal manures and B concentrations in the mixes, (5) study the availability of P to plants growing in the mixes, and (6) determine the microbial community and siderophores involved in the solubilization of Fe and its transfer to plants. Background: In recent years a major expansion of electricity production by coal combustion has taken place in Israel, the United States and the rest of the world. As a result, a large amount of CCPs are created that include bottom ash, fly ash, flue gas desulfurization (FGD) gypsum and other combustion products. In Israel 100,000 tons of fly ash (10% of total CCPs) are produced each year and in the US a total of 123 million tons of CCPs are produced each year with 71 million tons of fly ash, 18 million tons of bottom ash and 12 million tons of FGD gypsum. Many new scrubbers are being installed and will come on-line in the next 2 to 10 years and this will greatly expand the amount of FGD gypsum. One of the main substrates used in Israel for growth media is volcanic ash (scoria; tuff). The resemblance of bottom coal ash to tuff led us to the assumption that it is possible to substitute tuff with bottom ash. Similarly, bottom ash and FGD gypsum were considered excellent materials for creating growth mixes for agricultural and nursery production uses. In the experiments conducted, bottom ash was studied in Israel and bottom ash, fly ash and FGD gypsum was studied in the US. Major Achievements: In the US, mixes were tested that combine bottom ash, organic amendments (i.e. composts) and FGD gypsum and the best mixes supported growth of tomato, wheat and marigolds that were equal to or better than two commercial mixes used as a positive control. Plants grown on bottom ash in Israel also performed very well and microelements and radionuclides analyses conducted on plants grown on bottom coal ash proved it is safe to ingest the edible organs of these plants. According to these findings, approval to use bottom coal ash for growing vegetables and fruits was issued by the Israeli Ministry of Health. Implications: Bottom coal ash is a suitable substitute for volcanic ash (scoria; tuff) obtained from the Golan Heights as a growth medium in Israel. Recycling of bottom coal ash is more environmentally sustainable than mining a nonrenewable resource. The use of mixes containing CCPs was shown feasible for growing plants in the United States and is now being evaluated at a commercial nursery where red sunset maple trees are being grown in a pot-in-pot production system. In addition, because of the large amount of FGD gypsum that will become available, its use for production of agronomic crops is being expanded due to success of this study.