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1
Flammia, Madelyn. "Avoiding Desktop Disasters: Why Technical Communication Students should Learn about Mechanical Paste up Techniques." Journal of Technical Writing and Communication 23, no. 3 (July 1993): 287–95. http://dx.doi.org/10.2190/bldx-08k6-34ae-xx1k.
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Today many students learn how to use desktop programs such as PageMaker and Ventura in technical communication courses; however, few of those students are also learning the principles of graphic design underlying the production of mechanicals. The ability to use a desktop publishing program does not necessarily guarantee the ability to produce well-designed and effective documents. In fact, the growing use of desktop publishing software has led to a proliferation of documents that violate all the rules of good design. This article describes a technical publications course in which students gain a better understanding of the principles of design and layout by using mechanical paste up techniques. When required to use mechanical paste up in addition to desktop publishing software, students acquired a more thorough understanding of grids and white space as well as a greater confidence in their abilities to do page design.
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SIEGL, Regina Maura Coli, Tathiane Larissa LENZI, Gabriel Tilli POLITANO, Monique De BENEDETTO, José Carlos Petorossi IMPARATO, and Sérgio Luiz PINHEIRO. "Two endodontics techniques analysis in primary molars with fistula." RGO - Revista Gaúcha de Odontologia 63, no. 2 (June 2015): 187–94. http://dx.doi.org/10.1590/1981-863720150002000082990.
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OBJECTIVE: The purpose of this research was to follow the radiolucent area (pixels) in the furcation area and the behavior of the endodontically treated deciduous molars with different simplified echniques. METHODS: The treatments were performed without the duct instrumentation using relative isolation and two drugs were applied, as follows: G1: Guedes-Pinto paste (GP) and G2: CTZ paste (CTZ) for the pulp chamber filling. The radiolucent areas in the furcation region of deciduous molars were obtained from previous x-rays, after 6 and 12 months of the endodontic treatment and was analysed by l Image Tool 3.0 by two blinded examiners. In order to analyse the calibration between the examiners, Kappa test was used and for comparison of the initial radiographic image, analysis of variance was used after 6 and 12 months of each group and Tukey spost-hoc test. T-Student test was used for comparison between groups. RESULTS: There was a reduction of radiolucent area after 6 (p<0.01) and 12 months (p<0.01) in the teeth treated with CTZ paste. In the teeth treated with PG there was not reduction of radiolucent area after 12 months. (p= 0,09). CONCLUSION: Although the clinical signs were similar in both groups after 12 months of follow up, only teeth treated with CTZ showed reduction of radiolucent area in the furca area after 6 and 12 months.
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Mondaca, S. L., C. A. Leiva, C. A. Acuña, and E. A. Serey. "Flow Enhancement of Mineral Pastes to Increase Water Recovery in Tailings: A Matlab-Based Imaging Processing Tool." Scientific Programming 2020 (May 26, 2020): 1–9. http://dx.doi.org/10.1155/2020/5607242.
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The rate of growth of mining copper industry in Chile requires higher consumption of water, which is a resource limited in quality and quantity and a major point of concern in present times. In addition, the efficient use of water is restricted due to high levels of evaporation (10 to 15 (l/m2) per day), in particular at the north highland mining sites (Chile). On the contrary, the final disposal of tailings is mainly on pond, which loses water by evaporation and in some cases by percolation. An alternative are the paste thickeners, which generate stable paste (70% solids), reducing evaporation and percolation and therefore reducing water make up. Water is a resource with more demand as the industries are expanding, making the water recovery processes more of a necessity than a simple upgrade in efficiency. This technology was developed in Canada (early 80s) and it has widely been used in Australia (arid zones with similar weather conditions to Chile), although few plants are using this technology. The tendency in the near future is to move from open ponds to paste thickeners. One of the examples of this is Minera El Tesoro. This scenario requires developing technical capacity in both paste flow characterization and rheology modifiers (fluidity enhancer) in order to make possible the final disposal of this paste. In this context, a new technique is introduced and experimental results of fluidity modifiers are discussed. This study describes how water content affects the flow behavior and depositional geometry of tailings and silica flour pastes. The depositional angle determined from the flume tests, and the yield stresses is determined from slump test and a rheological model. Both techniques incorporate digital video and image analysis. The results indicate that the new technique can be incorporated in order to determine the proper solid content and modifiers to a given fluidity requirement. In addition, the experimental results showed that the pH controls strongly the fluid paste behavior.
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Musztyfaga-Staszuk, Małgorzata, Grzegorz Putynkowski, Robert Socha, Maciej Stodolny, and Piotr Panek. "Copper-Based Volumetric Filler Dedicated for Ag Paste for Depositing the Front Electrodes by Printing on Solar Si Cells." Materials 11, no. 12 (December 7, 2018): 2493. http://dx.doi.org/10.3390/ma11122493.
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In this work we present research results on a new paste NPCuXX (where: NP—new paste, CuXX—component, XX—a modifier consisting of Ni and other important elements) based on a copper composite (CuXX) for fabrication of front electrodes in silicon solar cells. The CuXX composite is obtained by chemical processing of copper powder particles and can be used in two ways: as an additive to commercially available paste or as a base material for a new paste, NPCuXX. The CuXX offers the possibility to exchange up to 30 and 50 wt.% Ag into Cu, which significantly decreases the solar cells material costs, and therefore, the overall solar cell price. Emphasis was placed on a proper mass suitable fabrication process of the CuXX component. The NPCuXX paste has been applied both to conventional cell structures such as aluminum-back surface field (Al-BSF) and passivated emitter and rear contact (PERC), and finally solar cells with front electrodes deposited by screen-printing method were fabricated and characterized by current-voltage techniques. This paper reports the first implementation of the copper volumetric material into a screen print paste used in a high-temperature metallization process to fabricate the front contacts of Si solar cells with a highest fill factor of 77.92 and 77.69% for the abovementioned structures, respectively.
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Clay, David W. "Mathtype, Version 3.0." Journal of Applied Mathematics and Stochastic Analysis 6, no. 3 (January 1, 1993): 287–88. http://dx.doi.org/10.1155/s1048953393000255.
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MathType is a mathematical equation editor in the Windows 3.1 environment. It lets you build up any kind of mathematical expression by using simple point-and-click techniques and then insert them into any Windows 3.1 compatible word processor; for instance, Word Perfect 5.1/5.2 for Windows, Word 2.0 for Windows, and AMI Pro 3.0 for Windows. An expression designed by MathType can be transferred into a word processor by using standard Cut and Paste commands or by using Object Linking and Embedding techniques.
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Samrudhi Khatod, Anuja Ikhar, Pradnya Nikhade, Manoj Chandak, Kaustubh Khatod, Akshay Jaiswal, Madhulika Chandak, Chanchal Rathi, and Nidhi Motwani. "Comparative Evaluation of Different Irrigation Techniques with Conventional Irrigation Technique for the Removal of Double Antibiotic Paste from Root Canal-An in vitro study." International Journal of Research in Pharmaceutical Sciences 11, no. 4 (September 28, 2020): 5578–83. http://dx.doi.org/10.26452/ijrps.v11i4.3194.
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Complete removal of infection, rendering root canal free of an organism is the prime aim of endodontic treatment. It cannot be achieved alone by biomechanical preparation due to the complexity of root canal treatment. Therefore the use of intracanal medicament is a must. The antibiotic paste is frequently used intracanal medicament, usually in regenerative cases. Hence the aim of the is to compare different irrigation technique for removal of double antibiotic paste from root canal through a stereomicroscope. 36 single-rooted were standardized to root length of 12mm then instrumented by Protaper rotary file up to size F4. Irrigation was done using sodium hypochlorite in between instrument change. The root canal was dried using paper point and filled by DAP and then randomly allocated to 3 groups(n=12) according to irrigation system used: conventional syringe irrigation (CSI), Passive ultrasonic irrigation(PUI), EndoVac (EV). Roots were then longitudinally sectioned using the diamond disk and studied under a stereomicroscope using a scoring scale. Data were evaluated using one way ANOVA and Tukey test. Among all experimental group CSI was least efficient. PUI and EV showed greater efficiency but no significant difference between PUI and EV, but a significant difference between CSI and PUI, EV (p< 0.05). Use of irrigation activation system results in efficient removal of DAP compared to CSI.
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Petrlová, J., S. Křížková, V. Šupálková, M. Masařík, V. Adam, L. Havel, K. J. Kramer, and R. Kizek. "The determination of avidin in genetically modified maize by voltammetric techniques." Plant, Soil and Environment 53, No. 8 (January 7, 2008): 345–49. http://dx.doi.org/10.17221/2185-pse.
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Quality assurance is a major issue in the food industry. The authenticity of food ingredients and their traceability are required by consumers and authorities. Plant species such as barley (<i>Hordeum vulgare</i>), rice (<i>Oryza sativa</i>), sunflower (<i>Helianthus annus</i>), wheat (<i>Triticum aestivum</i>) and maize (<i>Zea mays</i>) are very common objects of interest of genetic modification (GMO); therefore the development of specific assays for their specific detection and quantification of GMO are needed. Furthermore, the production and trade of genetically modified lines from an increasing number of plant species brings about the need for control within research, environmental risk assessment, labeling-legal, and consumers’ information purposes. Electrochemical sensors and biosensors based on modification of working electrode could be suitable tools for these purposes. Here, we report using of an avidin-modified carbon paste electrode for rapid and sensitive determination of avidin in plant extract solution and in a transgenic maize extract. The process could be used to determine avidin concentrations up to 3pM in solution and 170nM in a maize seed extract. Moreover, we applied the method to analyze different maize flours.
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Makrygianni, Marina, Filimon Zacharatos, Kostas Andritsos, Ioannis Theodorakos, Dimitris Reppas, Nikolaos Oikonomidis, Christos Spandonidis, and Ioanna Zergioti. "Eco-Friendly Lead-Free Solder Paste Printing via Laser-Induced Forward Transfer for the Assembly of Ultra-Fine Pitch Electronic Components." Materials 14, no. 12 (June 17, 2021): 3353. http://dx.doi.org/10.3390/ma14123353.
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Current challenges in printed circuit board (PCB) assembly require high-resolution deposition of ultra-fine pitch components (<0.3 mm and <60 μm respectively), high throughput and compatibility with flexible substrates, which are poorly met by the conventional deposition techniques (e.g., stencil printing). Laser-Induced Forward Transfer (LIFT) constitutes an excellent alternative for assembly of electronic components: it is fully compatible with lead-free soldering materials and offers high-resolution printing of solder paste bumps (<60 μm) and throughput (up to 10,000 pads/s). In this work, the laser-process conditions which allow control over the transfer of solder paste bumps and arrays, with form factors in line with the features of fine pitch PCBs, are investigated. The study of solder paste as a function of donor/receiver gap confirmed that controllable printing of bumps containing many microparticles is feasible for a gap < 100 μm from a donor layer thickness set at 100 and 150 μm. The transfer of solder bumps with resolution < 100 μm and solder micropatterns on different substrates, including PCB and silver pads, have been achieved. Finally, the successful operation of a LED interconnected to a pin connector bonded to a laser-printed solder micro-pattern was demonstrated.
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Zampini, Davide, Surendra P. Shah, and Hamlin M. Jennings. "Early age microstructure of the paste-aggregate interface and its evolution." Journal of Materials Research 13, no. 7 (July 1998): 1888–98. http://dx.doi.org/10.1557/jmr.1998.0268.
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The sequence of microstructural changes occurring at the wet paste-aggregate interface is documented at an age as early as 5 min using the environmental scanning electron microscope (ESEM). Unlike other microscopic techniques, the ESEM allows pastes of normal water: cement ratio to be observed at early ages without reducing the paste to a powder. Evolution of the paste-aggregate microstructure is followed up to an age of 24 h. The region adjacent to the aggregate surface contains a phase with a morphology referred to as a “sheaf of wheat” morphology. The same interfacial region in a 10-day-old specimen has a microstructure similar to the interfacial transition zone (ITZ) reported in the literature. Variations of the “sheaf of wheat” morphology due to original water-to-cement ratio, mixing energy, incorporation of silica fume, and drying are documented. As revealed by energy dispersive x-ray analysis (EDS), the microstructure contains significant amounts of calcium and silica. These results indicate that the observed morphology is likely to be a calcium silicate hydrate (C-S-H) product that is a precursor to type I C-S-H. A description of the evolution of the observed microstructural features is presented. The “sheaf of wheat” morphology appears to be a general precursor to morphologies commonly seen in mature pastes.
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Mommaerts, Maurice Y., Paul R. Depauw, and Erik Nout. "Ceramic 3D-Printed Titanium Cranioplasty." Craniomaxillofacial Trauma & Reconstruction 13, no. 4 (July 16, 2020): 329–33. http://dx.doi.org/10.1177/1943387520927916.
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Study Design: Inlay cranioplasties following partial craniectomy in tumor or trauma cases and onlay cranioplasties for reconstructions of residual developmental skull anomalies are frequently performed using CAD-CAM techniques. Objective: In this case series, we present a novel cranial implant design, being a combination of 3D-printed titanium grade 23 and calcium phosphate paste (CeTi). Methods: The titanium patient-specific implant, manufactured using selective laser melting, has a latticed border with interconnected micropores. The cranioplasty is miniscrew fixed and its border zone subsequently partially filled with calcium phosphate paste to promote osteoinduction and osteoconduction. From April 2017 to April 2019, 8 patients have been treated with such a CeTi implant. The inlay cranioplasties were each time revision surgeries of complicated cases. Results: All implants were successful after a limited follow-up time (range 18-42 months). There were no dehiscences and no infections, and no complaints of thermal conduction. Conclusions: The proposed CeTi cranial implant combines the strength of titanium implants with the biological integration potential of ceramic implants and seems particularly resistant to infection, probably due to the biofunctionalized titanium surface and the antimicrobial activity of elevated intracellular free calcium levels.
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Ivanova, Irina, and Viktor Mechtcherine. "Effects of Volume Fraction and Surface Area of Aggregates on the Static Yield Stress and Structural Build-Up of Fresh Concrete." Materials 13, no. 7 (March 27, 2020): 1551. http://dx.doi.org/10.3390/ma13071551.
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With increasing interest in the use of additive manufacturing techniques in the construction industry, static rheological properties of fresh concrete have necessarily come into focus. In particular, the knowledge and control of static yield stress (SYS) and its development over time are crucial for mastering formwork-free construction, e.g., by means of layered extrusion. Furthermore, solid understanding of the influences of various concrete constituents on the initial SYS of the mixture and the structural build-up rate is required for purposeful material design. This contribution is concentrated on the effect of aggregates on these rheological parameters. The volume fraction of aggregates was varied in the range of 35% to 55% by volume under condition of constant total surface area of the particles. The total surface area per unit volume of cement paste was equal to 5.00, 7.25 and 10.00 m²/L, conditioned on the constant volume fraction of aggregates. Both variations were enabled by changing the particle size distributions of the aggregates while holding the cement paste composition constant for all concrete mixtures. To characterise the SYS and the structural build-up, constant shear rate tests with a vane-geometry rotational rheometer were performed. It was found that in the ranges under investigation the variation in volume fraction had a more pronounced effect on the static rheological properties of concrete than did the variation in surface area. An accurate mathematical description of the relationship between the initial SYS of concrete and the relative volume fraction of aggregate based on the Chateau–Ovarlez–Trung model was proposed. Challenges in deriving a similar relationship for the structural build-up rate of concrete were highlighted.
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Nedeljković, Marija, Bahman Ghiassi, and Guang Ye. "Role of Curing Conditions and Precursor on the Microstructure and Phase Chemistry of Alkali-Activated Fly Ash and Slag Pastes." Materials 14, no. 8 (April 12, 2021): 1918. http://dx.doi.org/10.3390/ma14081918.
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Understanding the role of curing conditions on the microstructure and phase chemistry of alkali-activated materials (AAMs) is essential for the evaluation of the long-term performance as well as the optimization of the processing methods for achieving more durable AAMs-based concretes. However, this information cannot be obtained with the common material characterization techniques as they often deliver limited information on the chemical domains and proportions of reaction products. This paper presents the use of PhAse Recognition and Characterization (PARC) software to overcome this obstacle for the first time. A single precursor (ground granulated blast-furnace slag (GBFS)) and a binary precursor (50% GBFS–50% fly ash) alkali-activated paste are investigated. The pastes are prepared and then cured in sealed and unsealed conditions for up to one year. The development of the microstructure and phase chemistry are investigated with PARC, and the obtained results are compared with independent bulk analytical techniques X-ray Powder Fluorescence and X-ray Powder Diffraction. PARC allowed the determination of the type of reaction products and GBFS and FA’s spatial distribution and degree of reaction at different curing ages and conditions. The results showed that the pastes react at different rates with the dominant reaction products of Mg-rich gel around GBFS particles, i.e., Ca-Mg-Na-Al-Si, and with Ca-Na-Al-Si gel, in the bulk paste. The microstructure evolution was significantly affected in the unsealed curing conditions due to the Na+ loss. The effect of the curing conditions was more pronounced in the binary system.
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Briggs, Ed. "Minimizing Voiding in Bottom Terminated Components by Optimizing the Solder Paste Flux." International Symposium on Microelectronics 2016, no. 1 (October 1, 2016): 000505–10. http://dx.doi.org/10.4071/isom-2016-tha53.
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Abstract Perhaps the single biggest challenge in PCB assembly today is voiding under bottom terminated components (BTCs) such as QFNs (quad-flat-pack, no-leads), D-Paks, and LGAs (land grid arrays). Many bottom terminated components, such as QFNs, have a large thermal pad on the bottom side which provides excellent thermal and electrical grounding properties. However, effectively soldering these components to minimize thermal pad voiding can be a challenge. Many automotive electronics assemblers are increasing this challenge by requiring less than 10% voids to improve reliability. The large deposit of printed solder paste required to solder the thermal pad typically induces flux entrapment and subsequent voiding during the reflow process. Large voids and/or a high number of voids cause decreased thermal conductivity and lower the mechanical strength of the resulting solder joints. The large solder paste deposit required may also cause the component to float and open up the electrical connections around the perimeter of the component. Another factor affecting voiding has been the transition to lead-free solder, which has been marked by the use of various SAC alloys. Most applications for surface mount assembly use SAC305 (96.5Sn/3.0Ag/0.5Cu) with a melting temperature range of 217–220°C. The higher temperatures required for lead-free soldering and the increased surface tension of the SAC alloy exacerbate the voiding issue. This paper will focus on the techniques for optimizing the assembly process for QFN components, with a focus on minimizing voiding. Best practices for lead-free reflow profiling, stencil aperture design, solder paste volume control, and the importance of flux chemistry to minimize void formation will be discussed.
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Korokhina, A. V., and V. V. Koloda. "ARTIFACTS OF THE LATE BROZE AGE FROM MOKHNACH П SETTLEMENT." Archaeology and Early History of Ukraine 32, no. 3 (September 25, 2019): 165–75. http://dx.doi.org/10.37445/adiu.2019.03.13.
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The article aims to introduce new finds of the Late Bronze Age from Mokhnach П settlement site at the Sіverskyi Donets river.
Two archaeological object (pits 27 and 40) can be dated back to the Late Bronze Age. Finds are presented mostly by pottery sherds (31 units) discovered mostly in the excavation pit 1.
The research program of the pottery assemblage includes account of its planographic distribution, distribution due to the type of sherds, analysis of shape, ornamentation, size, surface finishing, plastic raw material and paste recipes of vessels. Morphological and ornamentation classifications were built on the basis of the scheme developed on materials of Mosolovka site and the settlements of middle flew of Sіverskyi Donets river. Research of the plastic raw material and paste recipes was conducted using visual microscopic analysis, abridged MGR-analysis and thin-section analysis.
Pottery assemblage includes 4 % of the total number of fragments discovered during excavations. Five pottery forms were identified: restricted and unrestricted jars, pot-like vessels, pots and ribbed vessels. Orifice diameters of jars, pot-like vessels and pots vary from 38.0 to 21.5 cm. Ribbed vessels on average are smaller than mentioned types and form to groups by size (with orifice diameters of 25 and 15—16 cm).
Three techniques and nine elements of ornamentation were identified. Make-up of both surfaces prevails, fine-toothed comb treatment and coarse-toothed comb treatment of Pokrovka type are also presented.
Two pottery fabrics can be distinguished in the assemblage with the naked eye. Five pottery samples were selected for purposes of technological analysis. Observations were conducted using the microscope on cross-cuts and fresh breaks of sherds before and after re-firing. Consequently two groups by features of plastic raw material and two paste recipes were identified. Both paste recipes include grog as an intentional addition.
Due to method of the abridged Matrix Group by Refiring (MGR) analysis the samples were re-fired in controlled conditions up to from 1100 to 1200 °C. The results showed the identity of the matrix of all samples — non-calcareous, slightly over-melted (sovM). Their local production is suggested. The thin-section analysis allowed to clarify technological features of the samples with raw material type 1, paste type 1.
Analyzed ceramic materials present traditions of the Wood-framed Graves entity. They mark new settlement site of the developed stage of the Wood-framed Graves entity and can be dated back to XVII—XVІ BC.
Small size of the ceramic assemblage restricts its informative capacity. The importance of the research lies in testing the program of complex analysis of ceramic assemblages.
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Borba, Camila, Cíntia Jacobsen, Guilherme Pauletto, Carina Michelon, and Mariana De Carlo Bello. "Diferentes técnicas para o tratamento de dentes com rizogênese incompleta e necrose pulpar: uma revisão sistemática." Revista da Faculdade de Odontologia de Porto Alegre 62, no. 1 (August 9, 2021): 129–50. http://dx.doi.org/10.22456/2177-0018.101686.
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Introduction: The objective of this systematic review was to compare the apexification techniques of calcium hydroxide (Ca(OH)2), or mineral trioxide aggregate (MTA), with the pulp regeneration technique, using cohort studies, and non-randomized and randomized clinical trials. Methods: The methodology was based on electronic research in the following databases: PubMed, MEDLINE, Google Scholar, SciELO, and LILACS. In addition, a manual search was carried out using the references that were listed in the articles found. Results: A total of 403 potentially eligible studies were found, with seven being included in the inclusion criteria of this systematic review. The seven studies involved a total of 312 teeth. The minimum time of a follow-up period was 12 months. The irrigation solution most used was sodium hypochlorite, for both of the apexification and revascularization techniques. The medication commonly chosen in the apexification groups was Ca(OH)2, with antibiotic triple paste in the revascularization groups. The clinical rate of success in the groups treated with revascularization varied from 76% to 100%, while in the groups treated with apexification, it ranged from 68% to 100%. Only two studies reached a success rate equal to 100%. Conclusions: Variable levels of evidence were observed in relation to the treatments. However, it was confirmed that revascularization is an excellent option since its outcomes produced a greater gain of thickness and root length, besides developing a decrease in the apical foramen.
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Sugo, Heber, Adrian W. Page, and Stephen Lawrence. "Influence of age on masonry bond strength and mortar microstructureThis article is one of a selection of papers published in this Special Issue on Masonry." Canadian Journal of Civil Engineering 34, no. 11 (November 2007): 1433–42. http://dx.doi.org/10.1139/l07-137.
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The effect of age on bond strength and mortar microstructure was investigated as part of an ongoing masonry bond strength research program at The University of Newcastle. Previous work has shown that both strength losses and strength gains occur with age. The potential loss of bond strength with time has structural implications as the design of masonry using the Australian masonry standard AS 3700–2001 is based on the 7 d bond strength. In this investigation, a single mortar-and-unit combination (dry pressed clay and 1:1:6 mortar) cured under ambient laboratory conditions was studied. Bond strength was determined at ages ranging from 3 to 365 d using a small-scale uniaxial tension test. Maximum bond strength was observed to occur at 180 d with strength minima occurring at 90 and 365 d. Scanning electron microscopy and X-ray diffraction techniques were used to further identify the mortar constituents and hydration levels. Changes in the density of the paste microstructure were observed up to 28 d, which correlated with the initial increase in bond strength. No other microstructural change to account for the strength variations between 28 and 365 d could be observed using these techniques.
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El-Din, Shaimaa Nasr, Magdy M. Ali, and Reham Hassan. "Comparison of Apically Extruded Debris Associated with Different Irrigation Techniques after Removal of Intracanal Medicaments." Open Access Macedonian Journal of Medical Sciences 9, no. D (August 20, 2021): 120–25. http://dx.doi.org/10.3889/oamjms.2021.6094.
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This study aimed to compare the effect of XP-endo Finisher file (XPF), passive ultrasonic irrigation (PUI) and conventional irrigation technique using side-vented needle (SVN) on the amount of apically extruded debris after the removal of calcium hydroxide Ca(OH)2 and double antibiotic paste (DAP). Materials and Methods: Sixty extracted human mandibular premolars were used. After decronation, all canals were prepared up to the ProTaper Next X4 file (Dentsply Maillefer, Ballaigues, Switzerland). After dryness, teeth were randomly assigned into 2 groups (n=30) according to the Type of intracanal medication used; Ca(OH)2 and DAP then incubated at 37 °C and 100% humidity. After one week, Samples in each group were randomly assigned to 3 subgroups (n=10) according to the method used for medicament removal: XPF, PUI and SVN. Debris extruded during the removal procedure were collected into pre-weighed Eppendorf tubes then left to dry in an incubator at 37°C for 15 days. The amount of extruded debris was assessed with an analytical balance and calculated by subtracting the initial weight from the final weight of the tube. Data were statistically analyzed using Kruskal-Wallis and Mann-Whitney U test. Results: there was no statistically significant difference regarding the amount of apically extruded debris after using the three irrigation techniques in removal of both Ca(OH)2 and DAP (P-value = 0.141, Effect size = 0.160) and (P-value = 0.237, Effect size = 0.073) respectively. Conclusions: Neither XPF nor PUI increase the risk of intracanal medicament extrusion beyond the apex.
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Cuesta, Ana, Ángeles G. De la Torre, Isabel Santacruz, Ana Diaz, Pavel Trtik, Mirko Holler, Barbara Lothenbach, and Miguel A. G. Aranda. "Quantitative disentanglement of nanocrystalline phases in cement pastes by synchrotron ptychographic X-ray tomography." IUCrJ 6, no. 3 (April 27, 2019): 473–91. http://dx.doi.org/10.1107/s2052252519003774.
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Mortars and concretes are ubiquitous materials with very complex hierarchical microstructures. To fully understand their main properties and to decrease their CO2 footprint, a sound description of their spatially resolved mineralogy is necessary. Developing this knowledge is very challenging as about half of the volume of hydrated cement is a nanocrystalline component, calcium silicate hydrate (C-S-H) gel. Furthermore, other poorly crystalline phases (e.g. iron siliceous hydrogarnet or silica oxide) may coexist, which are even more difficult to characterize. Traditional spatially resolved techniques such as electron microscopy involve complex sample preparation steps that often lead to artefacts (e.g. dehydration and microstructural changes). Here, synchrotron ptychographic tomography has been used to obtain spatially resolved information on three unaltered representative samples: neat Portland paste, Portland–calcite and Portland–fly-ash blend pastes with a spatial resolution below 100 nm in samples with a volume of up to 5 × 104 µm3. For the neat Portland paste, the ptychotomographic study gave densities of 2.11 and 2.52 g cm−3 and a content of 41.1 and 6.4 vol% for nanocrystalline C-S-H gel and poorly crystalline iron siliceous hydrogarnet, respectively. Furthermore, the spatially resolved volumetric mass-density information has allowed characterization of inner-product and outer-product C-S-H gels. The average density of the inner-product C-S-H is smaller than that of the outer product and its variability is larger. Full characterization of the pastes, including segmentation of the different components, is reported and the contents are compared with the results obtained by thermodynamic modelling.
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Miñano, Isabel, Francisco Benito, Manuel Valcuende, Carlos Rodríguez, and Carlos Parra. "Improvements in Aggregate-Paste Interface by the Hydration of Steelmaking Waste in Concretes and Mortars." Materials 12, no. 7 (April 9, 2019): 1147. http://dx.doi.org/10.3390/ma12071147.
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The objective of the experimental work is to study the mechanical properties in self-compacting concretes (SCC) in which part of the limestone aggregate has been replaced by granulated blast furnace slag (GBFS) in different percentages ranging from 0% to 60%. The results show that at early ages the SCC with the largest content in slag tend to have lower compressive strengths due to the poor compacting of the aggregates, although in the long-term their strength increases due to the reactivity of the slag. In fact, at the age of 365 days, the mortars made with the substitution of 50% of cement by ground GBFS reach compressive strength similar to that of the mortar made with 100% of cement. The consumption of calcium hydroxide during the hydration of the GBFS and the formation of hydrated calcium silicate (CSH) improve the mechanical properties of the slag-paste interface. The new compounds formed by the hydration of anhydrous oxides of the GBFS improve the aggregate-paste transition zone. The chemical interaction between the dissolution of the cement pore and the GBFS ends up generating new compounds on its surface. The increasing hydration of the GBFS produces a greater amount of silica gel that polymerises, densifying the matrix and reducing the porosity, which improves the mechanical properties of the concrete and perhaps its durability. The topography of the particles and their interface are analysed with atomic force microscopy techniques to assess the morphology depending on the aggregate used. On the other hand, a study was carried out of the aggregate-paste interface with scanning electronic microscope at different ages. It can be seen that in the contours of the hydrated GBFS particles, a band or ring forms with the new reaction products. The results obtained strengthen the previous conclusions. The new hydrated compounds fill the reaction ring, introducing chemical bonds between the aggregate and the interface, occupying part of the original pores or substituting spaces occupied originally by large portlandite crystals, of lesser mechanical strength and easily leached. For all this, the benefit is twofold. On the one hand, use is made of industrial by-products and, on the other hand, part of the destruction of natural quarries to obtain the necessary raw materials is avoided.
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Sushumna, I., R. K. Gupta, and E. Ruckenstein. "Stable, highly concentrated suspensions for electronic and ceramic materials applications." Journal of Materials Research 6, no. 5 (May 1991): 1082–93. http://dx.doi.org/10.1557/jmr.1991.1082.
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Highly concentrated solid-in-liquid suspensions find applications in a number of areas such as electronics, ceramics, paints, coatings, etc. Highly loaded, stable suspensions which exhibit desirable rheological characteristics (moderate viscosity, shear thinning behavior, thixotropy, and a small yield stress, for example), and which have high thermal or electrical conductivities are frequently sought after. We describe here some techniques which can be used to obtain such highly concentrated suspensions. These involve employing mixed size grades of particles and effective dispersants. For thermal paste applications, for example, compliant pastes of up to 78 vol. % solids with thermal conductivity values as high as 6 W/mK (hence, a few times greater than the values reported previously by others), low electrical conductivity, and moderate viscosity have been prepared by mixing different particle size grades of materials such as Al2O3, SiC, AlN, Al, and diamond. Effective dispersants, both commercial as well as those synthesized in our laboratory as novel variations of previously known molecular architectures, have been used to facilitate the achievement of these very high loading and stable suspensions.
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Lee, Seung-Tae, Dae-Wook Park, and Ki-Yong Ann. "Mitigating effect of chloride ions on sulfate attack of cement mortars with or without silica fume." Canadian Journal of Civil Engineering 35, no. 11 (November 2008): 1210–20. http://dx.doi.org/10.1139/l08-065.
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This paper presents a detailed experimental study on the sulfate attack of mortar specimens with or without silica fume exposed to sulfate and sulfate–chloride solutions (with the same concentration of SO42– ions) up to 510 d. The overall aim of the study is to investigate the beneficial effect of chloride ions on sulfate attack. In addition, the role of silica fume and water–binder ratio (w/b) in resisting sulfate attack is also reported. To qualitatively assess the performance of mortar specimens exposed to test solutions, visual examination and compressive strength and expansion tests were carried out. X-ray diffraction (XRD) and mercury intrusion porosimetry (MIP) techniques were also used to evaluate the products formed by hydration and chemical reaction and the change of porosity for paste samples. Results indicated that the presence of chloride ions in sulfate environments mitigated the deterioration of ordinary Portland cement mortar specimens, especially with a higher w/b, due to sulfate attack. It seems that the mitigating effect of chloride ions on sulfate attack is attributable to the increased solubility of sulfate products in the chloride-bearing sulfate solution, and the chemical binding of the ions to form Friedel’s salt.
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Bellaloui, Achour, Arezki Tagnit-Hamou, and Gérard Ballivy. "Comportement physico-chimique de mélanges à base de poussières de four de cimenterie et de cendres volantes." Canadian Geotechnical Journal 39, no. 4 (August 1, 2002): 960–70. http://dx.doi.org/10.1139/t02-025.
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Enhancing the value of the cement kiln dust so as to use it as an environmental barrier requires, amongst other things, the addition of fly ashes in order to improve the different properties needed to insure a better placing and a long term efficiency. Taking advantage of different experimental techniques, particular attention was devoted to the physicochemical behaviour of different kiln dusts associated with the fly ashes. Depending on the nature of the added compound, a different behaviour may condition the evolution of the mixtures with an effect on their stability. Indeed, this study has confirmed the improvement of the physicochemical properties of the dusts interacting with the fly ashes rich in silica and poor in lime, which argues well for their use as an environmental barrier. Moreover, the follow up has led to a better understanding of certain mechanisms generated by the systems dealt with. Hence, after hydration and different chemical transformations, some expansive phases as the ettringite, gypsum, syngenite, and portlandite develop in the paste, and therefore condition the behaviour of the mixtures worked out.Key words: cement kiln dusts, fly ashes, stabilization, physicochemistry, environmental barrier, lixiviation.[Journal translation]
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Namour, Mélanie, and Stephanie Theys. "Pulp Revascularization of Immature Permanent Teeth: A Review of the Literature and a Proposal of a New Clinical Protocol." Scientific World Journal 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/737503.
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Tissue engineering is a growing field. In the near future, it will probably be possible to generate a complete vital tooth from a single stem cell. Pulp revascularization is dependent on the ability of residual pulp and apical and periodontal stem cells to differentiate. These cells have the ability to generate a highly vascularized and a conjunctive rich living tissue. This one is able to colonize the available pulp space. Revascularization is a new treatment method for immature necrotic permanent teeth. Up to now, apexification procedures were applied for these teeth, using calcium dihydroxide or MTA to produce an artificial apical barrier. However, the pulp revascularization allows the stimulation of the apical development and the root maturation of immature teeth. Two pulp revascularization techniques are used in the literature, one using calcium dihydroxide and the second using a triple antibiotic paste. Based on these two different pulp revascularization protocols, which obtain the desired therapeutic success, the literature will be reviewed and analyzed according to the relevance of their choice of materials. Based on the literature, we propose a new relevant protocol and a new mixture of antibiotics.
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Hackel, Laetitia, Elise Rotureau, Aoife Morrin, and José Paulo Pinheiro. "Developing On-Site Trace Level Speciation of Lead, Cadmium and Zinc by Stripping Chronopotentiometry (SCP): Fast Screening and Quantification of Total Metal Concentrations." Molecules 26, no. 18 (September 10, 2021): 5502. http://dx.doi.org/10.3390/molecules26185502.
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Electrochemical stripping techniques are interesting candidates for carrying out onsite speciation of environmentally relevant trace metals due to the existing low-cost portable instrumentation available and the low detection limits that can be achieved. In this work, we describe the initial analyticaltechnique method development by quantifying the total metal concentrations using Stripping Chronopotentiometry (SCP). Carbon paste screen-printed electrodes were modified with thin films of mercury and used to quantify sub-nanomolar concentrations of lead and cadmium and sub-micromolar concentrations of zinc in river water. Low detection limits of 0.06 nM for Pb(II) and 0.04 nM for Cd(II) were obtained by the standard addition method using a SCP deposition time of 180 s. The SCP results obtained for Pb(II) and Cd(II) agreed with those of inductively coupled plasma mass spectrometry (ICP-MS). The coupling of SCP with screen-printed electrodes opens up excellent potential for the development of onsite speciation of trace metals. Due to the low analysis throughput obtained for the standard addition method, we also propose a new, more rapid screening Cd(II) internal standard methodology to significantly increase the number of samples that can be analyzed per day.
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Abrha, Tadesse, Rishi Pal, and R. C. Saini. "A Study on Voltametric Electro-kinetic Mechanism of Catechol at l-glutamic Acid-Carbon Paste Sensor." Journal of Surface Science and Technology 33, no. 1-2 (July 24, 2017): 1. http://dx.doi.org/10.18311/jsst/2017/6187.
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Quinones and quinoles, the pervasive components of living organism, perform different biochemical and physiological activities. These compounds have found their widespread applications as life saving drugs in cancer chemotherapy, antioxidant, anti bacterial and antifungal agents. These contribute as components of biological electron transfer chains located indifferent body parts. Electrochemical redox behavior of catechol using cyclic and differential pulse voltammetry at the surface of ℓ-glutamic acid modified carbon paste sensor was observed quite sensitive. There was a remarkable increase in the magnitude of both peak currents of catechol at the surface of modified electrode as compared to that of bare carbon paste electrode. Optimizations of working parameters for both techniques have been performed to perk up the working efficiency during experimentation. The electrochemical process occurs under both the diffusion and adsorption controlled conditions. The kinetic parameters such as heterogeneous electron transfer rate constant for electrode process (K<sub>h</sub>), diffusion coefficient (D), standard rate constant of surface reaction (k°), electron transfer coefficient (α) and the average surface concentrations of electro-active species (χ<sub>1</sub>&χ<sub>2</sub>) at the electro-chemical barriers catechol/o-quinone radical and o-quinone radical/o-quinone were calculated. The calculated value of K<sub>h</sub> lie in close vicinity to limiting value of a complete irreversible process and in far range of quasi-reversible process. In the higher range of applied scan rates at lower potentials of the used potential window, the forward scan revealed the formation of well stable reaction intermediate, at relatively slower rate. This is the rate determining step of the oxidation process but in case of reduction pulse of the same scan rate, there is no indication of any reduction intermediate moieties. The chemical process during electrochemical oxidation of catechol follows pseudo first order kinetics. Furthermore, a two step oxidation, Electronic-Chemical-Electronic-Chemical reactions (ECEC) mechanism has been proposed and single step reduction has been observed for the coupled redox process at the sensor/analyte interface.
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Wang, Quan Yu, Yi Chen, and Daniel O'Flynn. "A Scientific Study of Eastern Zhou Bronze Weapons with Tin-Rich Surface Decoration." Materials Science Forum 983 (March 2020): 47–55. http://dx.doi.org/10.4028/www.scientific.net/msf.983.47.
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In this paper we examined three bronze weapons with tin-rich surface decoration from the Eastern Zhou period: a sword (1966,0222.1) with a trellis pattern, a spearhead (1947,0712.426) with a hexagonal star pattern in the British Museum collections, and a sword (GT698) with a trellis pattern from a private collection. These weapons may have come from south eastern China, a region renowned for its weaponry production in the Eastern Zhou period, as both their styles and decorations are comparable to the sword of the Yue King Goujian and the spearhead of Wu King Fuchai, two of the most typical objects of this type. The manufacturing and surface tin-rich decoration techniques were investigated using microscopy, X-ray CT imaging, X-ray fluorescence spectrometry, scanning electron microscopy equipped with energy dispersive X-ray spectroscopy, and X-ray diffraction. The results showed that all the objects were made of high tin bronzes. The swords were made by casting a grip around the pre-cast blade and the pommel. The spearhead was an integral casting. The trellis pattern on the swords was probably produced by heating up a tin-rich paste applied to the surface and the thin hexagonal star decoration pattern on the spearhead was probably produced by brush painting with a mercury-tin amalgam followed by heating.
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Nasir, Muhammad, and Walid Al-Kutti. "Performance of Date Palm Ash as a Cementitious Material by Evaluating Strength, Durability, and Characterization." Buildings 9, no. 1 (December 28, 2018): 6. http://dx.doi.org/10.3390/buildings9010006.
Full textAbstract:
Cement manufacturing is indeed a major contributor to global warming that involves energy-intensive production processes along with emitting huge greenhouse gasses into the atmosphere. To adopt sustainable construction practices, agro-industrial waste materials as supplementary cementitious materials (SCMs) have been used by numerous researchers to partially replace conventional ordinary Portland cement (OPC) with SCMs by evaluating its optimum replacement dosage. This study aims to: (1) highlight the background of the date palm tree and the application of date palm waste as a construction material; (2) optimizing the dosage of date palm ash (DPA) as a cementitious material, at the replacement level of 10%, 20%, and 30%; and (3) understand the reaction kinetics by way of characterization techniques. DPA-based binary mixes were compared with each other and with the control (100% OPC mix) through fresh, mechanical, durability, and microstructural properties. The mechanism of reaction at early- and long-term period of curing was studied by characterization tests on paste, including nitrogen adsorption test (BET), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR). The outcome revealed 10% DPA as a strong and durable substitute to OPC, by formation of more Calcium Silicate Hydrate (C-S-H) and Calcium Aluminosilicate Hydrate (C-A-S-H) gel, whereas up to 30% DPA replacement can further maximize clinker replacement with reasonable performance, together with enhanced sustainability and reduced construction cost.
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Taha Ahmed, Ismail, Baraa Tareq Hammad, and Norziana Jamil. "A comparative analysis of image copy-move forgery detection algorithms based on hand and machine-crafted features." Indonesian Journal of Electrical Engineering and Computer Science 22, no. 2 (May 1, 2021): 1177. http://dx.doi.org/10.11591/ijeecs.v22.i2.pp1177-1190.
Full textAbstract:
<span>Digital image forgery (DIF) is the act of deliberate alteration of an image to change the details transmitted by it. The manipulation may either add, delete or alter any of the image features or contents, without leaving any hint of the change induced. In general, copy-move forgery, also referred to as replication, is the most common of the various kinds of passive image forgery techniques. In the copy-move forgery, the basic process is copy/paste from one area to another in the same image. Over the past few decades various image copy-move forgery detection (IC-MFDs) surveys have been existed. However, these surveys are not covered for both IC-MFD algorithms based hand-crafted features and IC-MFDs algorithms based machine-crafted features. Therefore, The paper presented a comparative analysis of IC-MFDs by collect various types of IC-MFDs and group them rely on their features used. Two groups, i.e. IC-MFDs based hand-crafted features and IC-MFDs based machine-crafted features. IC-MFD algorithms based hand-crafted features are the algorithms that detect the faked image depending on manual feature extraction while IC-MFD algorithms based machine-crafted features are the algorithms that detect the faked image automatically from image. Our hope that this presented analysis will to keep up-to-date the researchers in the field of IC-MFD.</span>
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De la Torre, Angeles G., Diana Londono-Zuluaga, Jesus D. Zea-Garcia, Marta García-Maté, Gema Álvarez-Pinazo, Miguel A. G. Aranda, Isabel Santacruz, et al. "X-ray diffraction, cements and environment, three worlds in one." MATEC Web of Conferences 149 (2018): 01003. http://dx.doi.org/10.1051/matecconf/201814901003.
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This keynote lecture will be focused on the strategies for reducing CO2 emissions in the cement production. Concretely, the production of ecocements with optimised formulations that yield reductions in CO2 emissions of up to 25%, when compared to OPC production. Phase assemblage has to be carefully optimised to be competitive and these new ecocements should develop compressive strengths of at least 50 MPa at 28 days of hydration. Optimised compositions of several ecocements will be discussed, but all of them are ye'elimite or calcium sulphoaluminate containing ones: belite-ye'elimite-ferrite (BYF), belite-alite-ye'elimite (BAY) and ye'elimite rich ones (CSA). The clinkering temperature of BYF and BAY has to be established to obtain the targeted phase assemblages. Moreover, the stabilisation of alpha-forms of belite is needed to develop high mechanical strengths at early ages. The benefits of the use of waste materials (such as fly ash or slag) as additions to ecocements are three-fold: lower CO2 emissions due to clinker replacement; valorisation of “useless” products that need a lot of landscape and the consequent efficient consumption of raw materials; and to enhance mechanical properties of the corresponding mortars. The design of appropriate CSA, BYF and BAY mortars, with the final aim of knowing and controlling the hydration mechanisms, will be presented. Particularly, the role of i) type and amount of set regulator (gypsum, anhydrite, etc.), ii) water/cement ratio (w/c); iii) superplasticiser; and iv) pozzolanic additions will be discussed. The role of these parameters in the microstructure and hydraulic behaviour has been investigated through traditional techniques as well as advanced synchrotron characterisation. The formers include laboratory/synchrotron X-ray powder diffraction combined with Rietveld methodology (to obtain phase assemblage), electron microscopy techniques for paste microstructure determination, rheological studies (to control the effect of the different additives, w/c ratio and setting time retarders) and mechanical tests (setting times, compressive strengths and dimensional stability). The latters comprise a group of techniques available at synchrotrons such as: i) high temperature x-ray diffraction for clinkering studies and ii) total scattering data to be analysed by pair distribution function, PDF.
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Gutiérrez, Ruby, Mónica Villaquirán-Caicedo, Sandra Ramírez-Benavides, Myriam Astudillo, and Daniel Mejía. "Evaluation of the Antibacterial Activity of a Geopolymer Mortar Based on Metakaolin Supplemented with TiO2 and CuO Particles Using Glass Waste as Fine Aggregate." Coatings 10, no. 2 (February 9, 2020): 157. http://dx.doi.org/10.3390/coatings10020157.
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Metakaolin-based geopolymer cements were produced by alkaline activation with a potassium hydroxide and potassium silicate solution. To produce the geopolymer composites, 10 wt.% titanium oxide (TiO2) and 5 wt.% copper oxide (CuO) nanoparticles were used. The geopolymer mortar was prepared using glass waste as fine aggregate. The raw materials and materials produced were characterized by X-ray diffraction, electron microscopy, and Fourier-transform infrared spectroscopy techniques. Likewise, the geopolymer samples were characterized to determine their physical properties, including their density, porosity, and absorption. The photocatalytic activity of the materials was evaluated by activating the nanoparticles in a chamber with UV–Vis light during 24 h; then, different tests were performed to determine the growth inhibition of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa bacteria in nutrient agar for times of up to 24 h. The study results showed that a geopolymer mortar containing glass waste as fine aggregate (GP-G) exhibited a water absorption 56.73% lower than that of the reference geopolymer paste without glass (GP). Likewise, glass particles allowed the material to have a smoother and more homogeneous surface. The pore volume and density of the GP-G were 37.97% lower and 40.36% higher, respectively, than those of the GP. The study with bacteria showed that, after 24 h in the culture media, the GP-G mortars exhibited a high inhibition capacity for the growth of P. aeruginosa from solutions of 10−4 mL and in solutions of 10−6 mL for E. coli and S. aureus. These results indicate the possibility of generating antibacterial surfaces by applying geopolymer composite.
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Paniagua, Fabian, Julio Paniagua, Angel Mateos, Rongzong Wu, and John T. Harvey. "Full-Scale Evaluation of Concrete-Asphalt Interphase in Thin Bonded Concrete Overlay on Asphalt Pavements." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 9 (July 17, 2020): 676–86. http://dx.doi.org/10.1177/0361198120931102.
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Thin bonded concrete overlay on asphalt (BCOA) pavements rely on concrete-asphalt bonding to resist traffic loading. To investigate variables affecting bonding, experimental data were used from 15 instrumented thin BCOA sections, with 11 tested with heavy vehicle simulators (HVS). Sections included three slab sizes, four rapid-strength concrete mixes, new and old asphalt bases, and three asphalt surface texturing techniques. Analysis of strain data from HVS testing served to determine the concrete-asphalt bonding condition. Laboratory testing and forensic data from the sections were also evaluated. Overall, the performance of concrete-asphalt bonding in the sections with 1.8 × 1.8 m (6 × 6 ft) slabs was excellent. In these sections, concrete-asphalt bonding remained intact throughout the HVS testing despite the unfavorable testing conditions, which included flooding of the section, channelized traffic at the slab edge, and HVS wheel (half axle) loading of up to 100 kN (22.5 kips). The sections with 3.6 × 3.6 m (12 × 12 ft) slabs presented a delamination band between the asphalt and concrete along the perimeter of the slabs. This delamination was a tensile break occurring in the asphalt around 5–10 mm (0.2–0.4 in.) below the concrete-asphalt interphase caused by the large vertical hygrothermal deformations in the slabs. Because of this asphalt failure, the concrete and asphalt worked as two independent layers near the transverse joints. Based on laboratory procedures, it was observed that cement paste penetration into the asphalt layer caused a reinforcing effect in the concrete-asphalt interphase. It was also observed that milling and micromilling did not improve the concrete-asphalt bonding.
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Górecki, Krzysztof, Barbara Dziurdzia, and Przemyslaw Ptak. "The influence of a soldering manner on thermal properties of LED modules." Soldering & Surface Mount Technology 30, no. 2 (April 3, 2018): 81–86. http://dx.doi.org/10.1108/ssmt-10-2017-0026.
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Purpose This paper aims to present the results of the influence of a manner of soldering light emitting diodes (LEDs) to the metal core printed circuit board on thermal parameters of the module LED containing these diodes. Design/methodology/approach Using the authors’ elaborated measuring method and the dedicated measurement set-up, transient thermal impedances of LED modules, mounted using different soldering processes and mounted to the heat-sink with different values of the moment of force, are measured. The obtained results of measurements are discussed. Findings It was shown experimentally that the manner of soldering could strongly influence efficiency of dissipation of heat generated in the module. The best thermal properties were obtained for soldering using vapour phase technology with vacuum and paste LFS-216LT. It was also proved that the moment of force used while mounting the considered modules on the heat-sink can result in a change of the value of thermal resistance of this module exceeding even 12 per cent. Research limitations/implications The investigations were performed for five LED modules operating at one, arbitrarily selected value of power dissipated in these modules mounted on the heat-sink of arbitrarily selected dimensions. Practical implications The obtained results of measurements could be usable for designers of mounting processes of power LED modules. Originality/value This paper presents the results of investigations of thermal properties of LED modules, in which different techniques of soldering are used. It was shown experimentally that the manner of soldering could strongly influence efficiency of dissipation of heat generated in the module. It was also proved that the moment of force used while mounting the considered modules on the heat-sink is important.
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Genç, Ziya Alper, Gabriele Lenzini, and Daniele Sgandurra. "Cut-and-Mouse and Ghost Control." Digital Threats: Research and Practice 2, no. 1 (March 2021): 1–23. http://dx.doi.org/10.1145/3431286.
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To protect their digital assets from malware attacks, most users and companies rely on antivirus (AV) software. AVs’ protection is a full-time task against malware: This is similar to a game where malware, e.g., through obfuscation and polymorphism, denial of service attacks, and malformed packets and parameters, tries to circumvent AV defences or make them crash. However, AVs react by complementing signature-based detection with anomaly or behavioral analysis, and by using OS protection, standard code, and binary protection techniques. Further, malware counter-acts, for instance, by using adversarial inputs to avoid detection, and so on. In this cat-and-mouse game, a winning strategy is trying to anticipate the move of the adversary by looking into one’s own weaknesses, seeing how the adversary can penetrate them, and building up appropriate defences or attacks. In this article, we play the role of malware developers and anticipate two novel moves for the malware side to demonstrate the weakness in the AVs and to improve the defences in AVs’ side. The first one consists in simulating mouse events to control AVs, namely, to send them mouse “clicks” to deactivate their protection. We prove that many AVs can be disabled in this way, and we call this class of attacks Ghost Control . The second one consists in controlling whitelisted applications, such as Notepad, by sending them keyboard events (such as “copy-and-paste”) to perform malicious operations on behalf of the malware. We prove that the anti-ransomware protection feature of AVs can be bypassed if we use Notepad as a “puppet” to rewrite the content of protected files as a ransomware would do. Playing with the words, and recalling the cat-and-mouse game, we call this class of attacks Cut-and-Mouse . We tested these two attacks on 29 AVs, and the results show that 14 AVs are vulnerable to Ghost Control attack while all 29 AV programs tested are found vulnerable to Cut-and-Mouse . Furthermore, we also show some weaknesses in additional protection mechanisms of AVs, such as sandboxing and CAPTCHA verification. We have engaged with the affected AV companies, and we reported the disclosure communication with them and their responses.
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Kuhn, Katharina, Heike Rudolph, David Zügel, Benjamin A. Just, Michael Hrusa, Thomas Martin, Sigmar Schnutenhaus, Jens Dreyhaupt, and Ralph G. Luthardt. "Influence of the Gingival Condition on the Performance of Different Gingival Displacement Methods—A Randomized Clinical Study." Journal of Clinical Medicine 10, no. 13 (June 22, 2021): 2747. http://dx.doi.org/10.3390/jcm10132747.
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This randomized clinical study examined the influence of the gingival condition—healthy versus mild inflammation—on sulcus representation and possible gingival recession for two gingival displacement procedures prior to conventional impression making. The interventions double cord technique or a kaolin paste containing aluminum chloride were applied to 40 probands. The opposite quadrant served as intrapersonal reference (split-mouth design). Precision impressions were then made. Extraoral digitization of the plaster models resulting from the reference impression prior to gingival displacement, the intervention impression and control impressions were the basis for the computer-aided three-dimensional analysis. After six months, a mild artificial gingivitis was induced, and the contralateral quadrant (cross-over design) was examined for the intervention. The gingivitis deteriorated the sulcus representation for the double cord technique group but did not affect the paste technique group. The gingival condition had no influence on the marginal gingiva height changes. The minor extent of those changes, which were measured up to six months after intervention at the palatal study site, were not considered to be in the clinically relevant range for gingival recession. For healthy gingiva, the cord technique showed superior sulcus representation compared to the paste technique. This advantage was lost to a great extent under the conditions of mild gingivitis.
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Zambrano, Telly Yarita Macias, Ingri Catherine Garcia Castro, Carmen Liliana Mera Plaza, and Ricardo Munoz Farfan. "Recovery of ancestral knowledge for production of traditional Manabí cocoa paste." International journal of life sciences 3, no. 1 (April 9, 2019): 71–78. http://dx.doi.org/10.29332/ijls.v3n1.274.
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The high family consumption of chocolates and cocoa powders with a high content of sugars and saturated fats, and on the contrary a very low content of cocoa paste is a problem. The objective was to recover the ancestral knowledge in the elaboration and conservation of the traditional Manabi cocoa paste. The experimental method was used for the elaboration and conservation of cocoa paste in clay pots with dried guineo leaves, in glass jars, at room temperature, and in refrigeration. Through the technique of interviewing 10 peasant women from the rural area of Chone, the way of elaboration and conservation of the cocoa ball was known. The main results: increase of the useful life of the cocoa ball wrapped in dried guinean leaves and stored in clay pots at room temperature, due to the decrease in humidity up to 180 days. As conclusions: little use of ancestral knowledge in the elaboration and conservation of traditional Manabí cocoa paste, unlike the consumption of refined chocolates with low cocoa content.
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Heuck, N., S. Müller, G. Palm, A. Bakin, and A. Waag. "Swelling Phenomena in Sintered Silver Die Attach Structures at High Temperatures: Reliability Problems and Solutions for an Operation above 350°C." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2010, HITEC (January 1, 2010): 000018–25. http://dx.doi.org/10.4071/hitec-nheuck-ta14.
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A very effective method to bond an electronic device to a substrate is the pressure assisted sintering of a sub-micron silver paste at temperatures between 150°C and 300°C. This technique-sometimes called “Silver-Sintering” or “Low Temperature Joining Technique (LTJT)” is already used in many power electronics industry applications. It provides die attach layers with excellent pull-strength of more than 100 MPa at room temperature and 30 MPa at 300°C. Additionally the electrical and thermal conductivity is nearly as good as it is in pure silver. Such sintered die attach layers are said to be stable up to temperatures above 500°C, but no detailed investigations in this temperature range are available up to now. Our recent investigations by shear- tests on monometallic chip/substrate-samples and dilatometer measurements showed a non-linear thermal expansion of the sintered structures above 350°C including a strong irreversible expansion of the whole sintered structure after long term heat treatments. Beyond the investigations on the swelling effect itself we present studies on the relationship between the expansion of the sintered layer and the resulting layer properties. Finally we discuss possibilities to take advantage out of this effect and additionally analyze options to reduce the swelling by adding SiC-particles to the silver paste. As a result, we demonstrate that swelling of the silver paste has to be taken into consideration when silver sintering is to be used for device operation temperatures above 350°C.
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Munoz-Martin, David, Yu Chen, Miguel Morales, and Carlos Molpeceres. "Overlapping Limitations for ps-Pulsed LIFT Printing of High Viscosity Metallic Pastes." Metals 10, no. 2 (January 22, 2020): 168. http://dx.doi.org/10.3390/met10020168.
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Laser-induced forward transfer (LIFT) technique has been used for printing a high viscosity (250 Pa·s) commercial silver paste with micron-size particles (1–4 µm). Volumetric pixels (voxels) transferred using single ps laser pulses are overlapped in order to obtain continuous metallic lines. However, interference problems between successive voxels is a major issue that must be solved before obtaining lines with good morphologies. The effects of the laser pulse energy, thickness of the donor paste film, and distance between successive voxels on the morphology of single voxels and lines are discussed. Due to the high viscosity of the paste, the void in the donor film after a printing event remains, and it negatively affects the physical transfer mechanism of the next laser pulses. When two laser pulses are fired at a short distance, there is no transfer at all. Only when the pulses are separated by a distance long enough to avoid interference but short enough to allow overlapping (≈100 µm), is it possible to print continuous lines in a single step. Finally, the knowledge obtained has allowed the printing of silver lines at high speeds (up to 60 m/s).
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Petrovic, Violeta, Vanja Opacic-Galic, and Slavoljub Zivkovic. "Postoperative pain after primary endodontic treatment and retreatment of asimptomatic teeth." Serbian Dental Journal 58, no. 2 (2011): 75–81. http://dx.doi.org/10.2298/sgs1102075p.
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Introduction. Postoperative pain may develop after chemomechanical preparation during endodontic treatment or retreatment. It is associated with acute apical periodontitis caused by bacteria penetrated from the root canal into the periapical tissue. The purpose of this study was to evaluate the incidence of postoperative pain during endodontic treatment after intracanal medication performed with calcium hydroxide (CH) paste or 1% chlorhexidine gel (CHX). Material and Methods. The study included 22 asymptomatic teeth in both male and female patients. Fourteen teeth had the diagnosis of pulp necrosis and the other eight were retreatment cases. The root canals were prepared by crown-down technique using K files and copious irrigation with 0.5% sodium hypochlorite (NaOCl). Intracanal dressing was performed using either calcium hydroxide paste or 1% CHX gel. Each medicament was placed in the root canals of eleven randomly selected teeth. The teeth were restored with temporary filling. Postoperative pain was registered during the seven day period between two appointments. The level of pain was rated as follows: no pain, mild pain, moderate pain and severe pain (flare-up). The obtained data was analyzed using Fisher exact test. The level of significance was ?=0.05. Results. Postoperative pain was absent in 77.3% of total number of treated teeth. Severe pain (flare-up) was registered in 2 cases (9%). There was no significant difference in pain incidence between the CH paste and CHX gel group (p=0.610). Conclusion. Endodontic procedure used in this study which considered root canal instrumentation and irrigation followed by intracanal medication with CH and CHX resulted in low incidence of postoperative pain.
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Oppert, Thomas, Rainer Dohle, Jörg Franke, and Stefan Härter. "Wafer Level Solder Bumping and Flip Chip Assembly with Solder Balls Down to 30μm." International Symposium on Microelectronics 2011, no. 1 (January 1, 2011): 000953–60. http://dx.doi.org/10.4071/isom-2011-tha3-paper1.
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The most important technology driver in the electronics industry is miniaturization mainly driven by size reduction on wafer level and cost. One of the interconnection technologies for fine pitch applications with the potential for highest integration and cost savings is Flip Chip technology. The commonly used method of generating fine pitch solder bumps is by electroplating the solder. This process is difficult to control or even impossible if it comes to ternary or quaternary alloys. The work described in this study addresses the limitations of existing bumping technologies by enabling low-cost, fine pitch bumping and the use of a very large variety of solder alloys. This flexibility in the selection of the solder materials and UBM stacks is a large advantage if it is essential to improve temperature cycling resistance, drop test resistance, or to increase electromigration lifetime. The technology allows rapid changeover between different low melting solder alloys. Tighter bump pitches and a better bump quality (no flux entrapment) are achievable than with screen printing of solder paste. Because no solder material is wasted, the material costs for precious metal alloys like Au80Sn20 are much lower than with other bumping processes. Solder bumps with a diameter between to date 30 μm and 500 μm as well as small and large batches can be manufactured with one cost efficient process. To explore this potential, cost-efficient solder bumping and automated assembly technologies for the processing of Flip Chips have been developed and qualified. Flip Chips used in this study are 10 mm by 10 mm in size, have a pitch of 100 μm and a solder ball diameter of 30 μm, 40 μm or 50μm, respectively. Wafer level solder application has been done using wafer level solder sphere transfer process or solder sphere jetting technology, respectively. The latter tool has been used for many years in the wafer level packaging industry for both Flip Chip and chip scale packaging applications. It is commonly known in the industry as a solder ball bumping equipment. For the described work the process was scaled down for processing solder spheres with a diameter of 30 μm what was never done before that way worldwide. The research has shown that the underfill process is one of the most crucial factors when it comes to Flip Chip miniaturization for high reliability applications. Therefore, high performance underfill material was qualified initially [1]. Final long term reliability testing has been done according to MIL-STD883G, method 1010.8, condition B up to thirteen thousand cycles with excellent performance of the highly miniaturized solder joints. SEM/EDX and other analysis techniques will be presented. Additionally, an analysis of the failure mechanism will be given and recommendations for key applications and further miniaturization will be outlined.
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Slavich, PG, and GH Petterson. "Anion exclusion effects on estimates of soil chloride and deep percolation." Soil Research 31, no. 4 (1993): 455. http://dx.doi.org/10.1071/sr9930455.
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Anion exclusion affects estimates of deep percolation determined using chloride mass balance models. This paper evaluates potential errors arising from ignoring anion exclusion in both soil analysis methods and model assumptions. Soil chloride analysis from saturated paste and 1:5 soil/water extracts are compared with that of field soil water extracted using a filter paper technique. The influence of anion exclusion on estimates of soil water chloride concentration (Clsw mmol/L) and chloride content per unit mass of soil (CIT mmol/kg soil), both which are required by chloride mass balance models, is examined for these methods. The relative importance of total electrolyte concentration and sodium absorption ratio (SAR) on the anion exclusion volume of a clay was also determined using a simple laboratory leaching technique. The chloride concentration of soil water at field moisture contents was more closely related to estimates calculated from saturated paste extracts than from 1:5 soil/water extracts. Although the amount of excluded water estimated in the saturated paste was larger than that estimated at the field water content, the proportion of non-excluded water in each was similar. The ClT was overestimated when analysis from saturation extracts was used. Electrolyte concentration and SAR were shown to have similar (but opposite) relative effects on the exclusion volume. However, because these variables were positively correlated, their effects were not apparent in the field samples. For the clay soil under study, deep percolation could be overestimated by up to 1.64 times if anion exclusion effects were ignored when using 1:5 extracts to estimate Clsw. The errors were considerably less if saturation extracts were used to estimate Clsw and ClT.
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Qin, Xuebin, Shifu Cui, Lang Liu, Pai Wang, Mei Wang, and Jie Xin. "Prediction of Mechanical Strength Based on Deep Learning Using the Scanning Electron Image of Microscopic Cemented Paste Backfill." Advances in Civil Engineering 2018 (November 1, 2018): 1–7. http://dx.doi.org/10.1155/2018/6245728.
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The mechanical strength of cemented backfill is an important indicator in mining filling. To study the nonlinear relationship between cemented paste backfill (CPB) and mechanical response, a deep learning technique is employed to establish the end-to-end mapping relationship between the scanning electron microscope (SEM) images and mechanical strength. A seven-layer convolution neural network is set up in the experiment, and the relationship between the SEM image and mechanical strength is established. In addition, the difference between the measured and predicted values is calculated and the mean and variance of the error are analyzed. The average accuracy of the mechanical strength prediction is found to be 8.28%. Thus, the proposed method provides a new technique for the quantitative analysis of mechanical strength of microscale CPB.
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Krejzek, P., P. Heneman, and J. Mareček. "Technical analysis of a back supply of heated rendering-plant fat the disc drier." Research in Agricultural Engineering 50, No. 1 (February 8, 2012): 28–30. http://dx.doi.org/10.17221/4923-rae.
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The fulfilment of the subject of the Act No. 76/2002 Dig. on integrated prevention reduces energy consumption and increases hygienic safety of a thermal treatment of animal tissues at veterinary decontamination institutes. By making use of a back supply of heated rendering-plant fat to the continuous disc drier KDS 250 the so-called fritting effect is induced speeding up the evaporation of residual water and reducing the redrying time of the meat and bone paste. An analysis proved a reduced consumption of specific energy, whereby the demand for the best available technique (BAT) is met.
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Oliveira, Lilian Vieira, Anahi de Paula Melo, Priscilla Barbosa Ferreira Soares, Juliane Maria Guerreiro Tanomaru, Carlos José Soares, and Camilla Christian Gomes Moura. "Modified revascularization technique in permanent molars. A case series." Research, Society and Development 10, no. 5 (May 4, 2021): e20810514532. http://dx.doi.org/10.33448/rsd-v10i5.14532.
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There are few reports of regenerative endodontic procedures in molars, and most using manual root canal preparation. This case series describes a modified revascularization technique used in permanent molars (five patients between 9 and 16 years old). Patients were referred by an emergency service and a diagnostic hypothesis was made based on the patient's reports. At the first appointment, coronal preparation was performed using Hedstroem files and Gates Glidden drills, followed by complete root canal preparation with rotary NiTi files. Calcium hydroxide (Ca(OH)2) paste was used as intracanal medication. At the second appointment, intracanal medication was removed, followed by final irrigation with EDTA under ultrasonic agitation, and the clot was promoted. The entrances of the canals were sealed using a mineral trioxide aggregate sealer (MTA) and provisionally restored with a light-cured glass ionomer. All teeth were finally restored using direct composite resin restoration and were followed for up to 18 months, checking pain, edema, and fistula during clinical evaluation. Radiographic examinations were performed to assess apical repair until 15 months, where root apex closure and canal reduction were observed. After 6 months, evidence of healing was observed in all cases. It was possible to confirm that endodontic regeneration after mechanized root canal preparation, use of a MTA sealer, and direct composite resin restoration in molars is a promising option for maintaining permanent molars in adolescents.
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Stanislav, Olga. "CHARACTERISTICS OF SYNTACTIC SEPARATION IN THE LITERATURE OF FRENCH SURREALISM (linguistic and cultural aspects of research)." PROBLEMS OF SEMANTICS, PRAGMATICS AND COGNITIVE LINGUISTICS 32 (2017): 149–61. http://dx.doi.org/10.17721/2663-6530.2017.32.15.
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The article deals with the problem of such kind of syntactic connection as separation, which is characteristic of the artistic language of modern French literature, surrealistic in particular. The analysis showed that in texts of the surrealistic direction of the technique of "automatic" writing, the effect of the "unexpected" creates the compositional chaos of the works, their structurally unsystematic pattern, a kind of paste-up, illogicality and subjectivism of the authors' associations. It was established that the basic principles of artistic surrealism in the syntax of the modern French language were expressed through the use of the irrational connection of words, sentences, the text as a whole, the violation of the syntactic hierarchy, proportions, structural syntactic segmentation, separation.
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Hun Yuk, Ji, Inmu Kim, Hyun Jin Nam, and Sung-Hoon Choa. "Highly Stretchable and Durable Nanocomposite Bow-Tie Antenna for Wearable Application." Journal of Nanoscience and Nanotechnology 21, no. 5 (May 1, 2021): 2980–86. http://dx.doi.org/10.1166/jnn.2021.19134.
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We present a highly stretchable and compact bow-tie antenna which operates at 5 GHz for wearable applications. The dimensions of the bow-tie antenna were 7.9 mm×17.8 mm. The stretchable antenna was fabricated with a composite mixture of silver flake and polymer binder. The composite paste was printed on polyurethane and textile using the screen printing technique. The RF performances, stretchability, bendability, and durability of the antennas were evaluated, which are critical requirements in wearable electronics. The stretchable bow-tie antennas showed excellent RF performances and stretchability up to a stretching strain of 40%. The antennas could be bent up to a bending radius of 20 mm without degrading RF performance. The stretchable antennas also exhibited outstanding mechanical endurance after 10,000 cyclic stretching tests. The antennas were not affected by the presence of the body and showed very stable RF performances, exhibiting promising results for mobile and wearable applications.
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Renteria, Anabel, Luisa F. Garcia, Jorge A. Diaz, Luis C. Delfin, Jaime E. Regis, Elizabeth I. Reza, David Espalin, Tzu-Liang Bill Tseng, and Yirong Lin. "Fabrication of bulk alumina structures with humidity sensing capabilities using direct ink write technique." Rapid Prototyping Journal 27, no. 4 (May 18, 2021): 822–33. http://dx.doi.org/10.1108/rpj-12-2019-0322.
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Purpose The purpose of this study is to evaluate different 3D structures for humidity sensing that will enable the fabrication of complex geometries with high moisture sensitivity. Design/methodology/approach Humidity sensors based on alumina ceramics were fabricated using direct ink write (DIW) technique. Different engineered surface area, polymer binder ratio and post-processing treatment were considered to increase moisture sensitivity. Findings It was found that the binder ratio plays an important role in controlling the rheology of the paste during printing and determining the pore size after post-processing treatment. The sensibility of the fabricated humidity sensor was investigated by measuring its capacitance response toward relative humidity (RH) varying from 40% to 90% RH at 25°C. It is shown that using 3D lattice design, printed alumina humidity sensor could improve sensitivity up to 31.6 pF/RH%, over an order of magnitude higher than solid alumina. Originality/value Most of the alumina humidity sensors available are films in nature because of manufacturing difficulties, which limited its potential of higher sensitivity, and thus broader applications. In this paper, a novel 3D alumina humidity sensor was fabricated using DIW 3D printing technology.
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Shearer, Catherine, Ken Holcomb, and Jim Haley. "Shrinking Package Footprint by Embedding Top-Side Real Estate Using Core-to-Core Joining." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2015, DPC (January 1, 2015): 001982–2014. http://dx.doi.org/10.4071/2015dpc-tha22.
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The electronics industry trend continues to be to continually increase capability and performance within an existing or smaller footprint. Shoehorning all of the required components onto the exterior surface of the PCB has become an increasingly difficult puzzle. The use of stacked microvias instead of plated through holes and stacked ICs in various configurations has freed up some real estate. The use of ever smaller passive devices also saves space, but reintroduces old issues such as tombstoning. The ideal solution would be to provide ‘surface’ real estate within the architecture of the circuit board – like moving items from a desk to a bookshelf – by embedding components into the board. In this paper, an alternative strategy is presented for embedded components. Sub-PCB constructions are built and populated on both sides, and then are joined using an interposer with sintering conductive paste interconnects. Sintering paste z-axis interconnections have been successfully used in this type of core-to-core joining for many years. The combination of the sintering paste interconnect and an interposer element is the key to enabling this architecture. This manufacturing strategy presents a number of advantages. The board may be broken down into logical substructures such as high density, core or RF portions. Each of the sub-PCBs can be fabricated according to best manufacturing practices for that portion of the circuit board rather than trying to fabricate a single complicated board. Yield losses from sequential process steps and multiple laminations may be reduced. The embedded components may be assembled onto the sub-PCBs using conventional solder reflow technology. The component placement can facilitate point-of-source architecture for high electrical performance. The process flow and some laboratory demonstrations of this technique will be presented in this paper.
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Jin Nam, Hyun, Ji-Hun Yuk, Kyu Song, Young Sun Kim, Su-Yong Nam, and Se-Hoon Park. "Printed Electrode for High-Performance Bow-Tie Antenna by Photonic Sintering Process." Journal of Nanoscience and Nanotechnology 21, no. 12 (December 1, 2021): 5881–89. http://dx.doi.org/10.1166/jnn.2021.19509.
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Recently, flexible electronic device technology has evolved beyond curved devices with the development of flexible/stretchable devices that can be crumpled or stretched. Both elasticity and durability are essential for these devices, which should have high-conductivity for antennas and repeatability for sensors. In addition, electronic-skins, which can have a direct impact on the human-body, should be harmless to the human-body and should not be deformed by contact with sweat or organic matter. In this study, PDMS substrates were used to satisfy the above conditions. PDMS is used to fabricate human-friendly, flexible/stretchable substrates, and it has excellent repeat durability characteristics. To improve the adhesion of these PDMS films and electrodes, conductive paste was produced based on PDMS resins of the same properties. In addition, two types of Ag particles were selected as conductive fillers because the electrode characteristics of the antenna application requires excellent conductivity, and conductive paste were produced using flake Ag, which could affect conductivity, and Ag nanoparticles that affect stretchability and repeatability. The paste was applied using a high-efficiency printing technique. The printed electrodes were cured in a thermal oven. For higher conductivity, photonic-sintering was carried out during post-processing. As a result, 1.1117×106 (S/m) had excellent conductivity, performed well in repeated tensile-durability experiments of 30% to 100 times, and produced a bow-tie antenna for the above electrodes. As a result of tensing up to 35% through a Network-Analyzer, there was no performance change in the resonance-frequency or return-loss values, and excellent electrodes were developed that would achieve excellent performance even if they are applied in the sub-frequency area of 5G-antennas in the future.
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Sousa, S. J. G., and J. N. F. Holanda. "Compaction behavior of dry granulated red wall tile paste prepared using raw materials from Rio de Janeiro State." Cerâmica 57, no. 341 (March 2011): 50–55. http://dx.doi.org/10.1590/s0366-69132011000100007.
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This work presents the results of a study about on the compaction behavior of a dry granulated red wall tile paste. The ceramic paste was formulated using raw materials of the Rio de Janeiro state. The raw materials were dry-ground and then microgranulated using a mixer of high intensity. The produced powder was characterized regarding X-ray diffraction, chemical composition, granule size analysis and morphology. The moisture content of the granulated powder (moisture mass/dry mass) varied between 0 and 10%. The granulated powder with different moisture contents was submitted to cold compaction process using a uniaxial die-pressing technique with compaction pressure up to 60 MPa. The compaction behavior of the wall tile powder was evaluated through compaction response and compaction rate diagrams. The development of the microstructure during compaction process was followed by scanning electron microscopy. The experimental results show that the green density of the tile compacts behaves as a function of moisture content. It was also found that the compaction process is ruled, at the applied pressure range, by two dominant mechanisms including granule rearrangement and plastic deformation. The rate of densification is high initially, but then decreases rapidly for pressures above apparent yield pressure (2.44 - 5.38 MPa). In addition, the better compaction efficiency was found to be influenced by the moisture content.
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Wang, Song, and Ming Xie. "Microstructures and Properties of Y2O3/La2O3/Cu Composite by Internal Oxidation." Applied Mechanics and Materials 236-237 (November 2012): 109–12. http://dx.doi.org/10.4028/www.scientific.net/amm.236-237.109.
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The 1.5%Y2O3/1.5%La2O3/Cu composite was prepared by oxygen and nitrogen atomization spray deposition technique and internal oxidation. The microstructures, hardness, strength, electrical conductivity and arc erosion surface of the composite were investigated by optical light microscope, scanning electron microscope, micro-hardness tester, tensile test and arc erosion experiment. The results show that, with the increasing of internal oxidation temperature, the grains of the composite grow up obviously. When the internal oxidation reaches to 1000°C, the matrix grains begin to appear annealing twins. The micro-hardness was 436HV, the ultimate tensile strength was 580MPa, yield tensile strength was 503MPa, elongation of alloy was 8.7% and the electrical conductivity was 87% IACS of the composite by internal oxidation at 1000°C for 2h.The arc erosion surface shows a large number of paste-like coagulum and bubbles. Introduction