WorldWideScience

Sample records for all-ceramic tubesheet assembly

  1. Evaluation of an all-ceramic tubesheet assembly for a hot gas filter

    Energy Technology Data Exchange (ETDEWEB)

    Bitner, J.L. [Mallett Technology, Inc., Canonsburg, PA (United States); Mallett, R.H. [Mallett Technology, Inc., Research Triangle Park, NC (United States); Eggerstedt, P.M. [Industrial Filter and Pump Mfg. Co., Cicero, IL (United States); Swindeman, R.W. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    A 10-inch thick, all-ceramic tubesheet design is evaluated for differential pressure and thermal conditions. Primary stresses from differential pressure are well within a safe allowable. The calculated peak thermal stresses at local discontinuities approach the modules of rupture for the ceramic material. Kiln tests were performed to demonstrate differential temperatures between hot center and cooler rim do not cause failures or visible tensile cracks. There appear to be mitigating mechanisms and design features in the Industrial Filter and Pump (IF and P) Mfg. Co. all-ceramic tubesheet design concept that add forgiveness in accommodating differential pressure and thermal loading stresses. A material characterization program on the ceramic materials is recommended.

  2. Ceramic tubesheet design analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mallett, R.H.; Swindeman, R.W.

    1996-06-01

    A transport combustor is being commissioned at the Southern Services facility in Wilsonville, Alabama to provide a gaseous product for the assessment of hot-gas filtering systems. One of the barrier filters incorporates a ceramic tubesheet to support candle filters. The ceramic tubesheet, designed and manufactured by Industrial Filter and Pump Manufacturing Company (EF&PM), is unique and offers distinct advantages over metallic systems in terms of density, resistance to corrosion, and resistance to creep at operating temperatures above 815{degrees}C (1500{degrees}F). Nevertheless, the operational requirements of the ceramic tubesheet are severe. The tubesheet is almost 1.5 m in (55 in.) in diameter, has many penetrations, and must support the weight of the ceramic filters, coal ash accumulation, and a pressure drop (one atmosphere). Further, thermal stresses related to steady state and transient conditions will occur. To gain a better understanding of the structural performance limitations, a contract was placed with Mallett Technology, Inc. to perform a thermal and structural analysis of the tubesheet design. The design analysis specification and a preliminary design analysis were completed in the early part of 1995. The analyses indicated that modifications to the design were necessary to reduce thermal stress, and it was necessary to complete the redesign before the final thermal/mechanical analysis could be undertaken. The preliminary analysis identified the need to confirm that the physical and mechanical properties data used in the design were representative of the material in the tubesheet. Subsequently, few exploratory tests were performed at ORNL to evaluate the ceramic structural material.

  3. Thermal and structural analysis of a filter vessel ceramic tubesheet

    Energy Technology Data Exchange (ETDEWEB)

    Mallett, R.H. [Mallett Technology, Inc., Research Triangle Park, NC (United States); Swindeman, R.W. [Oak Ridge National Lab., TN (United States); Zievers, J.F. [Industrial Filter & Pump Mfg. Co., Cicero, IL (United States)

    1995-08-01

    A ceramic tubesheet assembly for a hot gas filter vessel is analyzed using the finite element method to determine stresses under differential pressure loading. The stresses include local concentration effects. Selection of the stress measures for evaluation of structural integrity is discussed. Specification of stress limits based upon limited data is considered. Stress results from this ongoing design analysis technology project are shown for one design concept.

  4. Steam generator tubesheet waterlancing at Bruce B

    Energy Technology Data Exchange (ETDEWEB)

    Persad, R. [Babcock and Wilcox Canada, Cambridge, Ontario (Canada); Eybergen, D. [Bruce Power, Tiverton, Ontario (Canada)

    2006-07-01

    High pressure water cleaning of steam generator secondary side tubesheet surfaces is an important and effective strategy for reducing or eliminating under-deposit chemical attack of the tubing. At the Bruce B station, reaching the interior of the tube bundle with a high-pressure water lance is particularly challenging due to the requirement to setup on-boiler equipment within the containment bellows. This paper presents how these and other design constraints were solved with new equipment. Also discussed is the application of new high-resolution inter-tube video probe capability to the Bruce B steam generator tubesheets. (author)

  5. Prestresses in bilayered all-ceramic restorations

    NARCIS (Netherlands)

    Aboushelib, M.N.; Feilzer, A.J.; de Jager, N.; Kleverlaan, C.J.

    2008-01-01

    Introduction: A general trend in all ceramic systems is to use veneering ceramics of slightly lower thermal expansion coefficients compared with that of the framework resulting in a positive mismatch in thermal expansion coefficient (+ΔTEC). The concept behind this TEC mismatch is to generate compre

  6. A Simple Tubesheet Layout Program for Heat Exchangers

    Directory of Open Access Journals (Sweden)

    S. Murali

    2008-01-01

    Full Text Available The development of tubesheet layout program for shell and tube heat exchangers is presented in this study. Program is written in AutoLISP language, which provides standard tubesheet layout drawing as per standard codes and non standard tubsheet in AutoCAD Environment. The program computes the optimal number of tube count and lays out drawing with respecting constraints, including the shell ID, number of passes, center to center distance of tubes and tube outer diameter. Tubesheet layout drawing can be used as template for actual tubesheet. Furthermore the program is validated with open literature and shown good agreement with it. Besides the tubesheet for Heat exchangers this method can be extended to the tube counts of sheave plates and perforated plates of distillation column and Cooling Towers.

  7. [Key points in anterior esthetic restorations with all ceramic].

    Science.gov (United States)

    Luo, Xiaoping; Qian, Dongdong; Yuan, Yu; Meng, Xiangfeng

    2013-04-01

    This paper introduced the key points in fabricating anterior esthetic restorations with all ceramic materials, including pre-operative smile design, standard tooth preparation, provisional restoration fabrication, all ceramic materials selection, all ceramic restoration bonding, ceramic crack and fracture prevention. And then, the authors summarized and reviewed the clinical common problems in anterior esthetic restorations.

  8. CAD/CAM generated all-ceramic primary telescopic prostheses.

    Science.gov (United States)

    Kurbad, A; Ganz, S; Kurbad, S

    2012-01-01

    Computer-aided design and manufacturing (CAD/CAM) systems have proven effective not only for the manufacture of crown and bridge frameworks, inlays, onlays and veneers, but also for the generation of all-ceramic primary telescopic prostheses in more than 10 years of use in dental technology. The new InLab 4.0 software generation makes it possible to design and mill primary telescopic prostheses with CAD/CAM technology. The computer-generated raw crowns for these restorations require very little manual adaptation. The secondary crowns are manufactured by electroforming and bonded onto the tertiary structure or framework.

  9. Recent advances in materials for all-ceramic restorations.

    Science.gov (United States)

    Griggs, Jason A

    2007-07-01

    The past 3 years of research on materials for all-ceramic veneers, inlays, onlays, single-unit crowns, and multi-unit restorations are reviewed in this article. The primary changes in the field were the proliferation of zirconia-based frameworks and computer-aided fabrication of prostheses, and a trend toward more clinically relevant in vitro test methods. This article includes an overview of ceramic fabrication methods, suggestions for critical assessment of material property data, and a summary of clinical longevity for prostheses constructed of various materials.

  10. ALL-CERAMIC APPLIANCES FOR PROSTHETIC REHABILITATION IN YOUNG PATIENTS

    Directory of Open Access Journals (Sweden)

    Alexandru BASNO

    2016-03-01

    Full Text Available The aim of the present study was to assess a possible fixed rehabilitation in young patients, by means of CAD-CAM techniques. Materials and method. The CERCON substractive technique with zirconium oxide blanks was applied. Discussion. The obtained prosthetic structures are characterized by a better aesthetic integration, optimum marginal adaptation and suitable clinical longevity. Conclusions. All-ceramic prostheses appear as a biological solution in the prosthetic rehabilitation of young patients, as they require reduced removal of both enamel and dentin, while obeying the biological conservative principle of treatment.

  11. Restoration of Endodontically Treated Molars Using All Ceramic Endocrowns

    Directory of Open Access Journals (Sweden)

    Roopak Bose Carlos

    2013-01-01

    Full Text Available Clinical success of endodontically treated posterior teeth is determined by the postendodontic restoration. Several options have been proposed to restore endodontically treated teeth. Endocrowns represent a conservative and esthetic restorative alternative to full coverage crowns. The preparation consists of a circular equigingival butt-joint margin and central retention cavity into the entire pulp chamber constructing both the crown and the core as a single unit. The case reports discussed here are moderately damaged endodontically treated molars restored using all ceramic endocrowns fabricated using two different systems, namely, CAD/CAM and pressed ceramic.

  12. Bond strengths of all-ceramics: acid vs laser etching.

    Science.gov (United States)

    Gökçe, B; Ozpinar, B; Dündar, M; Cömlekoglu, E; Sen, B H; Güngör, M A

    2007-01-01

    Various applications of dental lasers on dental materials have been proposed for surface modifications. This study evaluated whether laser etching could be an alternative to hydrofluoric acid (HF) etching. One hundred and ten lithia-based all-ceramic specimens (Empress 2) (R: 4 mm, h: 4 mm) were prepared and divided into five groups (n = 22/group). The untreated specimens served as the control, while one of the experimental groups was treated with 9.5% HF for 30 seconds. Three remaining test groups were treated with different laser (Er:YAG laser wavelength:2940 nm, OpusDent) power settings: 300 mJ, 600 mJ and 900 mJ. Ten specimens in each group were luted to the other 10 specimens by a dual-curing cement (Variolink II), and shear-bond strength (SBS) tests were performed (Autograph, crosshead speed: 0.5 mm/minute). The results were statistically analyzed (Kruskal Wallis and Mann Whitney-U, alpha = .05). Mean SBS (MPa) were 31.9 +/- 4.0, 41.4 +/- 4.3, 42.8 +/- 6.2, 29.2 +/- 4.5 and 27.4 +/- 3.8 for the control and HF, 300, 600 and 900 mJ groups, respectively. SEM evaluations revealed different surface morphologies depending on the laser parameters. The differences between HF acid and 300 mJ, when compared with the control, 600 and 900 mJ groups, were significant (p < .05). The 300 mJ laser group exhibited the highest shear-bond strength values, indicating that laser etching could also be used for surface treatments.

  13. Design and technology parameters influence on durability for heat exchangers tube to tubesheet joints

    Science.gov (United States)

    Ripeanu, R. G.

    2017-02-01

    The main failures of heat exchangers are: corrosion of tubes and jacket, tubes blockage and failures of tube to tubesheet joints also by corrosion. The most critical zone is tube to tubesheet joints. Depending on types of tube to tubesheet joints, in order to better respect conditions of tension and compression, this paper analyses the tubesheet holes shapes, smooth and with a grove, on corrosion behavior. In the case of welding tubes with tubesheet, welding parameters modify corrosion behavior. Were realized welded joints by three welding regimes and tested at corrosion in two media, tap water and industrial water. Were tested also samples made of smooth tubes, finned tubes and tubes coated with a passive product as applied by a heat exchanger manufacturer. For all samples, the roughness parameters were measured, before and after the corrosion tests. The obtained corrosion rates show that stress values and their distribution along the joint modify the corrosion behavior. The optimum welding parameters were established in order to increase the joint durability. The paper has shown that passive product used is not proper chosen and the technology of obtaining rolled thread pipes diminishes tubes’ durability by increasing the corrosion rate.

  14. The teaching of all-ceramic restorations in North American dental schools: materials and techniques employed.

    Science.gov (United States)

    Frazier, K B; Mjör, I A

    1997-01-01

    North American dental schools were surveyed to determine the types of clinical experiences and the extent of material use that predoctoral students encounter with restorative procedures that employ all-ceramic materials. The results were based on an overall response rate of 80% from the 64 surveyed schools. The majority (96%) of the 51 schools responding to the survey did offer an opportunity to become experienced with all-ceramic restorations. The selection of bases and liners for all-ceramic restorations included dentin adhesive agents, glass ionomer materials, and calcium hydroxide products, by a ratio of 5:4:1, respectively. The most commonly used impression material types were addition silicone and polyether. One or both of these materials were used by every school. Dicor glass ceramic and alumina core ceramic were the most commonly used materials by the responding schools for veneers, onlays, and crowns. Dicor glass ceramic and CAD/CAM ceramic were most commonly used for inlays. Crowns were made of more different all-ceramic material types than the other restoration classes. Fabrication of all-ceramic restorations was primarily by commercial laboratories and school technicians. Students have hands-on experience in the fabrication of all-ceramic restorations in 6% of the responding schools. Luting agents for all-ceramic restorations include dual-cured resin, in 96% of the responding schools, light-cured resin, 43%, and glass ionomer cement, 33%. Zinc phosphate, chemical-cured composite, and polycarboxylate were used by less than one fourth of the respondents. Only resin-based composite materials were used to lute ceramic veneers. Rubber dam was applied primarily during luting procedures involving all-ceramic inlays and onlays. Crowns and veneers were isolated by this method in less than 30% of the responding schools. Finishing procedures with all-ceramic restorations were accomplished with three or more instruments by 89% of the schools.

  15. The teaching of all-ceramic restorations in Scandinavian dental schools: a survey.

    Science.gov (United States)

    Jokstad, A; Mjör, I A; Frazier, K B

    1996-06-01

    The study was designed to survey the curricular requirements, types of clinical experience, and materials/ techniques used in teaching programs for all-ceramic restorations in Scandinavian dental schools. All 13 dental schools responded. Ten offered some clinical experience to pre-doctoral students, but only one required one all-ceramic restoration. The departments of fixed prosthodontics had the main teaching responsibility. All-ceramic crowns were taught at 9, veneers at 7, and inlays/onlays at 10 dental schools. A wide range of different teaching concepts, materials, and views on indications and contraindications was reported. It appears as if all-ceramic restorations are regarded as experimental by the teaching institutions, although the dental industry and some practitioners strongly recommend these types of restorations.

  16. The clinical potential and limits of the all-ceramic fixed partial denture restorations

    Directory of Open Access Journals (Sweden)

    Harry Laksono

    2007-12-01

    Full Text Available High-strength all-ceramic systems for fixed partial dentures (FPDs is gaining popularity as an alternative to the well established metal-ceramic FPDs. Several new framework materials and technique such as lithium disilicate, aluminum oxide and yttrium tetragonal zirconia polycrystal have been developed with improved strength, marginal discrepancy and esthetics. Since not every all-ceramic system can be used for a variety application, proper selection of the materials is an important for the success of all-ceramic FPDs. The longevity of dental restorations is an important health concern and the clinician placed great emphasis on mechanical properties to define the clinical indication of the ceramic materials because of their brittleness and low fracture toughness. The stronger and tougher framework material would improve the reliability and the longevity of dental restoration. To fabricated of an all-ceramic FPDs, material would be required with a flexural strength in excess of 300 MPa and fracture toughness 3 MPa/m½. Zirconium has a better mechanical properties than alumina and lithium disilicate glass-ceramic, result from the transformation toughening, free of glass phase and minimal flaws. Whereas lithium disilicate glass-ceramic has a better translucency than alumina and zirconium based ceramic, result from the higher content of glass phase than that two materials. The purpose of this article is to present the information that can guide the practioner in the decision making process about all-ceramic FPDs systems. It can be concluded that the all-ceramic FPDs are seems to be an acceptable clinically prosthodontic treatment according to the short-term studies and the lithium disilicate and alumina-based ceramic materials are acceptable for 3 units anterior FPDs, whereas zirconia-based ceramic are acceptable for 3–5 units anterior and posterior FPDs with 2 pontics. However, further investigation and more clinical long-term follow-up studies

  17. Biomechanical Analysis of Individual All-Ceramic Abutments Used in Dental Implantology

    Directory of Open Access Journals (Sweden)

    Ziębowicz B.

    2016-09-01

    Full Text Available The paper presents the results of finite element analysis and experimental testing under simulated physiological loading conditions on issues shaping the functional properties of individual all-ceramic abutments manufactured by CAD/CAM technology. The conducted research have cognitive significance showing the all-ceramic abutment behavior, as a key element of the implantological system, under the action of cyclic load. The aim of this study was evaluation the fatigue behavior of yttria-stabilized zirconia abutment submitted to cyclic stresses, conducted in accordance with EN ISO 14801 applies to dynamic fatigue tests of endosseous dental implants.

  18. All-Ceramic Body Flap Qualified for Space Flight on X38

    Science.gov (United States)

    Pfeiffer, H.; Peetz, K.

    2002-01-01

    electromechanical actuator having a third hot bearing. The hinge line gap at the front part of the body flap is closed by a dynamic sealing system to minimize the flow of very hot gases to the leeward side. The paper in hand reports on design, manufacturing and assembly, together with the qualification of the body flaps and their components while the qualification test of the complete flap assembly is brought into focus. Flight readiness was approved by a series of qualification tests representing the full load spectrum of the X- 38 mission. It covered acceptance -, ascend vibration -, thermal transient -, static pressure - and finally descend vibration tests. Special facilities have been developed and manufactured for ground qualification of the flap assembly and the critical subcomponents. The manufacture and qualification of the X-38 body flaps represent a true milestone in the application of CMC. The stringent requirements and constraints, resulting from the assembly of many complex subcompo- nents and vehicle interfaces, require high material quality and precise manufacturing tolerances. Each qualification - and flight hardware element is therefore subjected to rigorous specifications, following detailed manufacturing process procedures with extensive quality control steps, as well as comprehensive documentation of design, analysis, manufacturing, assembly, interface control and vehicle integration. This challenge has been accepted and the objective to utilize MAN Technology's C/SiC as hot, load-carrying structures has reached a promising threshold. Material maturity as well as manufacturing competence is at a level where design and fabrication of CMC components for a operational re-entry vehicle can be proposed. The implementation of lightweight, durable ceramic hot structures is an innovative step forward in new spacecraft design. 1Name of Conference to which abstract is53 rd IAC 2Submission StatusFirst Submission 3TitleAll-Ceramic Body Flap Qualified for Space 4Authors

  19. All-ceramic restorations for complete-mouth rehabilitation in dentinogenesis imperfecta: a case report.

    Science.gov (United States)

    Moundouri-Andritsakis, Heleni; Kourtis, Stephanos G; Andritsakis, Demetrios P

    2002-10-01

    Prosthetic treatment of patients with dentinogenesis imperfecta is a challenge for the dental practitioner because numerous factors have to be considered. The use of all-ceramic restorations to rehabilitate the dentition of a young patient with dentinogenesis imperfecta is reported. Clinical and laboratory procedures are described.

  20. Fracture Rates and Lifetime Estimations of CAD/CAM All-ceramic Restorations.

    Science.gov (United States)

    Belli, R; Petschelt, A; Hofner, B; Hajtó, J; Scherrer, S S; Lohbauer, U

    2016-01-01

    The gathering of clinical data on fractures of dental restorations through prospective clinical trials is a labor- and time-consuming enterprise. Here, we propose an unconventional approach for collecting large datasets, from which clinical information on indirect restorations can be retrospectively analyzed. The authors accessed the database of an industry-scale machining center in Germany and obtained information on 34,911 computer-aided design (CAD)/computer-aided manufacturing (CAM) all-ceramic posterior restorations. The fractures of bridges, crowns, onlays, and inlays fabricated from different all-ceramic systems over a period of 3.5 y were reported by dentists and entered in the database. Survival analyses and estimations of future life revealed differences in performance among ZrO2-based restorations and lithium disilicate and leucite-reinforced glass-ceramics.

  1. Effect of luting media on the compressive strengths of two types of all-ceramic crown.

    Science.gov (United States)

    McCormick, J T; Rowland, W; Shillingburg, H T; Duncanson, M G

    1993-06-01

    This study evaluated the effect of selected luting media on the compressive strength of two types of all-ceramic crown. Tooth preparation was standardized; each preparation had a shoulder width of approximately 1.2 mm, and all internal preparation angles were rounded. Hi-Ceram and Dicor all-ceramic crowns were fabricated and cemented into the preparations with zinc phosphate, glass-ionomer, or composite resin cement. Coronal compressive fracture strengths were determined, using a set of unrestored teeth as a control. There were no statistically significant differences among the mean compressive strengths of the three luting media, and there was no statistically significant difference between the mean compressive strength of Dicor and that of the natural tooth control.

  2. CAD/CAM fabricated single-unit all-ceramic post-core-crown restoration

    Directory of Open Access Journals (Sweden)

    Thilla Sekar Vinothkumar

    2011-01-01

    Full Text Available This case report explains about an innovative treatment strategy for the management of damaged anterior teeth with reduced incisal clearance by means of a single-unit all-ceramic post-core-crown zirconia ceramic restoration fabricated by Computer-aided designing and computer-aided manufacturing (CAD/CAM technology. The reinforced zirconia ceramics allow fabrication of durable esthetic restorations in cases with high functional loading and the unification of the post, core, and crown in a single unit decreases the frequency of failure by creating a monobloc effect. In addition, the use of CAD/CAM technology for designing and fabricating ceramic restorations offers the option of expeditiously preparing these high-strength all-ceramic restorations.

  3. Longevity of Single-Tooth All-Ceramic CAD/CAM Restorations: A Meta-Analysis

    Science.gov (United States)

    2013-07-01

    from 3 to 11 years. Medicina Oral Patologia Oral Cirugia Bucal, 15 (3), e531-e537. Griggs J. (2007). Recent advances in materials for all-ceramic...University of the Health Sciences in partial fulfillment of the requirements of the degree of Master of Science in Oral Biology June 2013...the thesis requirement for the Master of Science degree in Oral Biology at the June 2013 graduation. Thesis Committee: Kim E. Diefenderfe CAPT

  4. Clinical evaluation comparing the fit of all-ceramic crowns obtained from silicone and digital intraoral impressions

    NARCIS (Netherlands)

    Zarauz, C.; Valverde, A.; Martinez-Rus, F.; Hassan, B.; Pradies, G.

    2016-01-01

    Objectives The aim of this study is to compare the fit of all-ceramic crowns fabricated from conventional silicone impressions with the fit of all-ceramic crowns fabricated from intraoral digital impressions. Methods Twenty patients with 26 posterior teeth with a prosthetic demand were selected for

  5. Topological design of all-ceramic dental bridges for enhancing fracture resistance.

    Science.gov (United States)

    Zhang, Zhongpu; Chen, Junning; Li, Eric; Li, Wei; Swain, Michael; Li, Qing

    2016-06-01

    Layered all-ceramic systems have been increasingly adopted in major dental prostheses. However, ceramics are inherently brittle, and they often subject to premature failure under high occlusion forces especially in the posterior region. This study aimed to develop mechanically sound novel topological designs for all-ceramic dental bridges by minimizing the fracture incidence under given loading conditions. A bi-directional evolutionary structural optimization (BESO) technique is implemented within the extended finite element method (XFEM) framework. Extended finite element method allows modeling crack initiation and propagation inside all-ceramic restoration systems. Following this, BESO searches the optimum distribution of two different ceramic materials, namely porcelain and zirconia, for minimizing fracture incidence. A performance index, as per a ratio of peak tensile stress to material strength, is used as a design objective. In this study, the novel XFEM based BESO topology optimization significantly improved structural strength by minimizing performance index for suppressing fracture incidence in the structures. As expected, the fracture resistance and factor of safety of fixed partial dentures structure increased upon redistributing zirconia and porcelain in the optimal topological configuration. Dental CAD/CAM systems and the emerging 3D printing technology were commercially available to facilitate implementation of such a computational design, exhibiting considerable potential for clinical application in the future. Copyright © 2015 John Wiley & Sons, Ltd.

  6. Illuminating light-dependent color shifts in core and veneer layers of dental all-ceramics.

    Science.gov (United States)

    Lee, Yong-Keun; Cha, Hyun-Suk; Yu, Bin

    2014-09-01

    The color of an object is perceived differently depending on the ambient light conditions. Since dental all-ceramic restorations are fabricated by building up several layers to reproduce the tooth shade, the optical properties of each layer should be optimized for successful shade reproduction. This study aimed to determine the separate contributions of the color shifts in each of the core and veneer layers of all-ceramics by switching the illuminating lights on the color shifts of layered ceramics. Specimens of seven kinds of core ceramics and the corresponding veneer ceramics for each core were fabricated with a layered thickness of 1.5 mm. A sintering ceramic was used as a reference core material. The Commission Internationale de l’Eclairage (CIE) color coordinates of core, veneer, and layered specimens were measured with a spectroradiometer under the CIE illuminant D65 (daylight), A (incandescent lamp), and F9 (fluorescent lamp) simulating lights. Color shifts of the layered specimens were primarily determined by the CIE a shifts (D65 to A switch) or by the CIE b shifts (D65 to F9 switch) of the veneer layer. The color coordinates shifts in the constituent layers differentially influenced those of the layered specimens by the kind of switched lights. Therefore, the optical properties of the constituent layers of all-ceramics should be controlled to reflect these findings.

  7. Geometrical Comparison of Numerical Models Used in the Design and Validation of Mechanically Rolled Tube-Tubesheet Joints

    DEFF Research Database (Denmark)

    Madsen, Søren Bøgelund; Ibsen, Claus Hessler; Gervang, Bo

    2015-01-01

    The focus of this paper is the validation and comparison of simplified numerical models of the mechanical rolling process used in tube to tubesheet joints. The investigated models is an axisymmetric model and planar models with plane strain and stress. There are different pros and cons...

  8. All- Ceramic Crown Preparation and the Remained wall Thickness of the Pulp Chamber

    Directory of Open Access Journals (Sweden)

    Mohammadzadeh Akhlaghi N.

    2012-12-01

    Full Text Available tatement of Problem: A minimally invasive method of preparation is essential to prevent tooth structure weakening and pulp irritation; especially for mandibular anterior single-tooth all-ceramic crowns. According to many investigations, one of the most important reasons of pulp injury caused by tooth preparation for different restorative procedures is reduced “remained wall thickness” (RWT. In order to protect the pulp from irritation, it is necessary to maintain a 0.5 mm of RWT.Purpose: The purpose of the present study was to evaluate the effect of all-ceramic crown preparation on pulp chamber RWT of mandibular incisors.Materials and Method: Mesiodistal and buccolingual initial images of 24 ex-tracted mandibular incisors were provided. The pulp chamber initial wall thick-nesses of buccal, lingual and proximal surfaces of cervical, 1and 2 mm above the cervical areas and also the incisal surfaces of incisal sections were measured using digital radiography and Photoshop software. After all-ceramic crown preparation, images were provided at the same initial positions. The initial and remained pulp chamber wall thicknesses were statistically evaluated and analyzed by ANOVA, paired t-test and a post hoc Tukey test.Results: Repeated measures ANOVA showed that the mean of pre- or post-preparation wall thicknesses were not significantly different for each surface at the three horizontal levels (p> 0.05. However, there were significant differences between the surfaces for each section. Comparison of pre- and post-preparation wall thicknesses revealed significant differences (p< 0.05. Proximal surfaces of cervical sections had the least RWT (0.42±0.12.Conclusion: According to the results of the present study, the least amount of initial and remained wall thicknesses of pulp chamber were related to the proximal surfaces, particularly in cervical areas. Therefore a reduction of preparation to 0.7 mm is suggested to prevent future pulp injury for

  9. Fracture load of implant-supported zirconia all-ceramic crowns luted with various cements.

    Science.gov (United States)

    Lim, Hyun-Pil; Yoo, Jeong-Min; Park, Sang-Won; Yang, Hong-So

    2010-01-01

    This study compared the fracture load and failure types of implant-supported zirconia all-ceramic crowns cemented with various luting agents. The ceramic frameworks were fabricated from a presintered yttria-stabilized zirconium dioxide block using computer-aided design/computer-assisted manufacturing technology, and were then veneered with feldspathic porcelain. Three luting agents were used. Composite resin cement (1,560.78 +/- 39.43 N) showed the highest mean fracture load, followed by acrylic/urethane cement (1,116.20 +/- 77.32 N) and zinc oxide eugenol cement (741.21 +/- 41.95 N) (P < .05). The types of failure varied between groups.

  10. Micro-CT evaluation of the marginal fit of CAD/CAM all ceramic crowns

    Science.gov (United States)

    Brenes, Christian

    Objectives: Evaluate the marginal fit of CAD/CAM all ceramic crowns made from lithium disilicate and zirconia using two different fabrication protocols (model and model-less). METHODS: Forty anterior all ceramic restorations (20 lithium disilicate, 20 zirconia) were fabricated using a CEREC Bluecam scanner. Two different fabrication methods were used: a full digital approach and a printed model. Completed crowns were cemented and marginal gap was evaluated using Micro-CT. Each specimen was analyzed in sagittal and trans-axial orientations, allowing a 360° evaluation of the vertical and horizontal fit. RESULTS: Vertical measurements in the lingual, distal and mesial views had and estimated marginal gap from 101.9 to 133.9 microns for E-max crowns and 126.4 to 165.4 microns for zirconia. No significant differences were found between model and model-less techniques. CONCLUSION: Lithium disilicate restorations exhibited a more accurate and consistent marginal adaptation when compared to zirconia crowns. No statistically significant differences were observed when comparing model or model-less approaches.

  11. A new classification system for all-ceramic and ceramic-like restorative materials.

    Science.gov (United States)

    Gracis, Stefano; Thompson, Van P; Ferencz, Jonathan L; Silva, Nelson R F A; Bonfante, Estevam A

    2015-01-01

    Classification systems for all-ceramic materials are useful for communication and educational purposes and warrant continuous revisions and updates to incorporate new materials. This article proposes a classification system for ceramic and ceramic-like restorative materials in an attempt to systematize and include a new class of materials. This new classification system categorizes ceramic restorative materials into three families: (1) glass-matrix ceramics, (2) polycrystalline ceramics, and (3) resin-matrix ceramics. Subfamilies are described in each group along with their composition, allowing for newly developed materials to be placed into the already existing main families. The criteria used to differentiate ceramic materials are based on the phase or phases present in their chemical composition. Thus, an all-ceramic material is classified according to whether a glass-matrix phase is present (glass-matrix ceramics) or absent (polycrystalline ceramics) or whether the material contains an organic matrix highly filled with ceramic particles (resin-matrix ceramics). Also presented are the manufacturers' clinical indications for the different materials and an overview of the different fabrication methods and whether they are used as framework materials or monolithic solutions. Current developments in ceramic materials not yet available to the dental market are discussed.

  12. Influence of thermomechanical fatigue loading on the fracture resistance of all-ceramic posterior crowns.

    Science.gov (United States)

    Senyilmaz, Dilek Pinar; Canay, Senay; Heydecke, Guido; Strub, Joerg Rudolf

    2010-06-01

    This study evaluated the fracture resistance and the survival rate of different all-ceramic crowns in-vitro after thermomechanical fatigue loading in comparison to porcelain-fused-to-metal posterior crowns. Sixteen crowns for human mandibular first molars were made of each of the following: Cercon, IPS-Empress 2 In-Ceram Zirconia, Procera AllZircon and porcelain-fused-to-metal. Half of the specimens of each group was thermocycled and dynamically loaded using a chewing simulator All samples were thereafter tested for the maximum fracture resistance. The survival rates after 1-2 million cycles in the artificial mouth were 100% in all the tested crown systems. The chewing simulation and thermocycling did not significantly decrease the fracture strength of the ceramic crowns (P>0.005). The median fracture load of Cercon, Procera AllZircon, In-Ceram Zirconia and PFM was significantly higher than IPS-Empress 2 both for loaded and non loaded groups (PZirconia and PFM was not significant (P>0.005). All-ceramic systems showed fracture load values similar to those of porcelain-fused-to-metal molar crowns and therefore may be considered for use in clinical studies.

  13. Reliability and strength of all-ceramic dental restorations fabricated by direct ceramic machining (DCM).

    Science.gov (United States)

    Filser, F; Kocher, P; Weibel, F; Lüthy, H; Schärer, P; Gauckler, L J

    2001-04-01

    All-ceramic dental bridges for the molar region are not yet available at reasonable costs. The novel direct ceramic machining (DCM) process allows an easy, reliable and rapid fabrication for all-ceramic dental restorations with high mechanical strength and good biocompatibility. In DCM, an enlarged framework is easily milled out of a pre-fabricated porous ceramic blank made of zirconia. After sintering to full density, no further time-consuming hard machining with diamond tools is needed. For individual esthetical requirements, the framework is coated with a veneer porcelain. Compared to the commercially available In-Ceram Alumina and IPS Empress2 restorations, the mechanical strength of zirconia frameworks is twice as high, allowing the restorations to bear the high mastication forces in the molar region. In terms of reliability, zirconia bridges fabricated by the DCM process are also superior to In-Ceram Alumina and IPS Empress2. A clinical study of three-unit dental bridges in the molar region found no problems after the first year of observation.

  14. Esthetic rehabilitation of anterior discolored teeth with lithium disilicate all-ceramic restorations.

    Science.gov (United States)

    Prevedello, Gustavo Costa; Vieira, Marcelo; Furuse, Adilson Yoshio; Correr, Gisele Maria; Gonzaga, Carla Castiglia

    2012-01-01

    The esthetic treatment of darkened anterior teeth represents a great challenge to dentists, because dental materials ideally should match the natural teeth. The optical behavior of the final restoration is determined by the color of the underlying tooth structure, the color of the luting agent, and the thickness and opacity of the ceramic material used. This article reports a case in which veneers and full crowns made of heat-pressed, lithium disilicate glass-ceramic were used for the esthetic rehabilitation of anterior discolored teeth. The patient was referred for treatment with defective anterior composite resin restorations, provisional acrylic resin crowns, darkening of the gingival margins, and uneven gingival contours. The multidisciplinary treatment plan included dental bleaching, periodontal plastic surgery to create gingival symmetry, and indirect all-ceramic restorations using high-opacity lithium disilicate glass-ceramic ingots. The treatment was successful and an excellent esthetic result was achieved.

  15. Method for calculating Average Temperature of Tubesheet in Heat Exchanger with Dual Tubesheets%双管板换热器管板平均金属温度的一种计算方法

    Institute of Scientific and Technical Information of China (English)

    袁博; 许学斌; 陈仓社

    2016-01-01

    Numerical simulation of heat transfer performance for the tubesheet and its adjacent fluid area in dual tubesheet heat exchanger was carried out in this article by using software Fluent. With heat transfer model established, the heat transfer mechanism was studied. The heat transfer equation was then provided and the method for calculating average metal temperature of tubesheet was proposed. It was shown that the simulation result was coincident with theoretical solution. Thus the correctness of heat transfer equation has been verified by simulation result.%利用FLUENT软件对双管板换热器管板及其邻近流体区域的传热特性进行了数值模拟研究,通过建立传热模型,对其传热机理进行了研究,给出了描述其传热过程的传热方程,提出了管板平均金属温度的计算方法。结果表明:管板平均金属温度的模拟结果与理论解相符,模拟结果验证了传热方程的正确性。

  16. An interdisciplinary noninvasive all-ceramic treatment concept for nonsyndromic oligodontia in adolescence.

    Science.gov (United States)

    Selz, Christian F; Jung, Britta A; Guess, Petra C

    2015-02-01

    Oligodontia has a substantial oral functional and psychosocial impact on the quality of life of children. The treatment of oligodontia in adolescence is an interdisciplinary approach which can include extraction of the primary teeth with orthodontic space closure, or prosthodontic rehabilitation. This case report describes a conservative approach for the rehabilitation of a 12-year-old patient with 19 ageneses (excluding third molars) of permanent teeth, infraocclusion of the persisting primary teeth, deep overbite, and reduced mesiodistal dimension of the maxillary incisors with a central diastema. The treatment plan to restore esthetics and function included an initial noninvasive prosthetic rehabilitation for deep bite correction with additive leucite-reinforced glass-ceramic onlays/veneers until definitive orthodontic and implant therapy are reevaluated and determined in adulthood. Esthetics, functional occlusion, and crown-to-root ratio remained stable over a follow-up period of 3 years. No signs of fractures within the all-ceramic restorations or symptoms of a temporomandibular disorder were evident.

  17. Students’ evaluation of preclinical simulation for all ceramic preparation (In Faculty of Dentistry Universiti Kebangsaan Malaysia

    Directory of Open Access Journals (Sweden)

    Natasya Ahmad Tarib

    2008-06-01

    Full Text Available The purpose of the study is to evaluate all ceramic crown (ACC preparations those were made by dental undergraduate students during the preclinical sessions. 104 plastic teeth were prepared by 4th year dental undergraduates during the preclinical session for ACC crown examined. The teeth were placed on the frasaco arches and were mounted in the frasaco head. The preparations were examined for the tapering, presence of undercuts, incisal and cingulum reductions as well as preparation of shoulder margin. Preparations were examined using hand instruments and visual. The sample size was 92 plastic teeth. Most of the preparations were acceptable with acceptable placement and types of margins, adequate axial and incisal reductions and acceptable tapered of the axial walls. On the other hand, most of the teeth showed absence of cingulum wall. Most of the crowns prepared by the students were acceptable. It showed that they understood the principles of crown preparation. Cingulum wall preparation has to be given greater emphasis as it is important in the retention and resistance of the restoration.

  18. Modified Y-TZP core design improves all-ceramic crown reliability.

    Science.gov (United States)

    Silva, N R F A; Bonfante, E A; Rafferty, B T; Zavanelli, R A; Rekow, E D; Thompson, V P; Coelho, P G

    2011-01-01

    This study tested the hypothesis that all-ceramic core-veneer system crown reliability is improved by modification of the core design. We modeled a tooth preparation by reducing the height of proximal walls by 1.5 mm and the occlusal surface by 2.0 mm. The CAD-based tooth preparation was replicated and positioned in a dental articulator for core and veneer fabrication. Standard (0.5 mm uniform thickness) and modified (2.5 mm height lingual and proximal cervical areas) core designs were produced, followed by the application of veneer porcelain for a total thickness of 1.5 mm. The crowns were cemented to 30-day-aged composite dies and were either single-load-to-failure or step-stress-accelerated fatigue-tested. Use of level probability plots showed significantly higher reliability for the modified core design group. The fatigue fracture modes were veneer chipping not exposing the core for the standard group, and exposing the veneer core interface for the modified group.

  19. All ceramic table tops analyzed using swept source optical coherence tomography

    Science.gov (United States)

    Stoica, Eniko Tunde; Marcauteanu, Corina; Sinescu, Cosmin; Negrutiu, Meda Lavinia; Topala, Florin; Duma, Virgil Florin; Bradu, Adrian; Podoleanu, Adrian Gh.

    2016-03-01

    Erosion is the progressive loss of tooth substance by chemical processes that do not involve bacterial action. The affected teeth can be restored by using IPS e.max Press "table tops", which replace the occlusal surfaces. In this study we applied a fast in-house Swept Source Optical Coherence Tomography (SS OCT) system to analyze IPS e.max Press "table tops". 12 maxillary first premolars have been extracted and prepared for "table tops". These restorations were subjected to 3000 alternating cycles of thermo-cycling in a range from -10°C to +50°C mechanical occlusal loads of 200 N were also applied. Using SS OCT we analyze the marginal seal of these restorations, before and after applying the mechanical and thermal strain. The characteristics of the SS OCT system utilized are presented. Its depth resolution, measured in air is 10 μm. The system is able to acquire entire volumetric reconstructions in 2.5 s. From the dataset acquired high resolution en-face projections were also produced. Thus, the interfaces between all ceramic "table tops" and natural teeth were analyzed on the cross-sections (i.e., the B-scans) produced and also on the volumetric (tri-dimensional (3D)) reconstructions, several open interfaces being detected. The study therefore demonstrates the utility of SS OCT for the analysis of lithium disilicate glass ceramic "table tops".

  20. Influence of Abutment Material on the Stress of Implant-supported All-ceramic Single Crown

    Institute of Scientific and Technical Information of China (English)

    GAO Shaohuai; DUAN Haiying; LI Zhiyong

    2012-01-01

    In order to investigate the influence of abutment material on the stress of implant-supported all-ceramic single crown,a 3D finite element model of implant-supported mandibular first premolar was computed by COSMOS/M 2.85 software.Alumina,zirconia,and titanium were used as abutment materials respectively.Vertical 600 N and horizontal 225 N load was applied on the occlusal surface.The results show that the stress distribution of implant-supported single crown was similar for different abutment materials.Maximum stresses within the crown were higher when titanium abutment was used.Maximum stress of titanium abutment was lower than that of ceramic abutment.Within the screw and fixture,maximum stresses had no difference under vertical loading but higher as titanium abutment was used under horizontal loading.There was no difference of maximum stress within the bone when different abutment materials were used.The present findings indicate that the abutment material had no influence on the stress distribution of implant-supported allceramic single crown but maximum stress when the titanium abutment was lower than that of ceramic abument.

  1. The influence of zirconia coping designs on the fracture load of all-ceramic molar crowns.

    Science.gov (United States)

    Kokubo, Yuji; Tsumita, Mitsuyoshi; Kano, Takamitsu; Fukushima, Shunji

    2011-01-01

    This study investigated the influence of zirconia coping designs on the fracture load of all-ceramic crown. Four kinds of zirconia copings were designed (a: Conventional zirconia coping with flat occlusal surface: thickness of the each coping is 0.6 mm evenly, and at the cervical margin area, the coping is adjusted sharply so as to fit preparation margin, b: Conventional zirconia coping with shoulder collar of 1 mm: thickness of the each coping is 0.6 mm evenly, and there is a collar of 0.6 mm from the margin, c: Zirconia coping with following original cuspal configuration (concave): two inclined cusp planes, and at the cervical margin area, the coping is adjusted sharply so as to fit preparation margin, and d: Zirconia coping with supporting configuration on the occlusal area: supporting configuration against the occlusal force, and at the cervical margin area, the coping is adjusted sharply so as to fit preparation margin) and porcelain was fired. Vertical and lateral load were conducted until fracture. Coping design affected the fracture load; conventional uniform thickness coping design showed the lowest load (a), whereas cuspal configuration to perform even thickness of porcelain showed the highest fracture load both load directions (c).

  2. Wear of primary teeth caused by opposed all-ceramic or stainless steel crowns

    Science.gov (United States)

    Bae, Ik-Hyun; Noh, Tae-Hwan; Ju, Sung-Won; Lee, Tae-Kyoung; Ahn, Jin-Soo; Jeong, Tae-Sung

    2016-01-01

    PURPOSE This study was conducted to evaluate the effects of full-coverage all-ceramic zirconia, lithium disilicate glass-ceramic, leucite glass-ceramic, or stainless steel crowns on antagonistic primary tooth wear. MATERIALS AND METHODS There were four study groups: the stainless steel (Steel) group, the leucite glass-ceramic (Leucite) group, the lithium disilicate glass-ceramic (Lithium) group, and the monolithic zirconia (Zirconia) group. Ten flat crown specimens were prepared per group; opposing teeth were prepared using primary canines. A wear test was conducted over 100,000 chewing cycles using a dual-axis chewing simulator and a 50 N masticating force, and wear losses of antagonistic teeth and restorative materials were calculated using a three-dimensional profiling system and an electronic scale, respectively. Statistical significance was determined using One-way ANOVA and Tukey's test (P.05). CONCLUSION Leucite glass-ceramic and lithium disilicate glass-ceramic cause more primary tooth wear than stainless steel or zirconia. PMID:26949487

  3. Internal fit of two all-ceramic systems and metal-ceramic crowns

    Science.gov (United States)

    MARTINS, Leandro Moura; LORENZONI, Fabio Cesar; de MELO, Alcides Oliveira; da SILVA, Luciana Mendonça; de OLIVEIRA, José Luiz G.; de OLIVEIRA, Pedro Cesar Garcia; BONFANTE, Gerson

    2012-01-01

    Objectives The aim of this study was to investigate the internal fit (IF) of glass-infiltrated alumina (ICA - In-Ceram Alumina), yttria-stabilized tetragonal zirconia polycrystals (Y-TZP - IPS e.max ZirCAD), and metal-ceramic (MC - Ni-Cr alloy) crowns. Material and Methods Sixty standardized resin-tooth replicas of a maxillary first molar were produced for crown placement and divided into 3 groups (n=20 each) according to the core material used (metal, ICA or Y-TZP). The IF of the crowns was measured using the replica technique, which employs a light body polyvinyl siloxane impression material to simulate the cement layer thickness. The data were analyzed according to the surfaces obtained for the occlusal space (OS), axial space (AS) and total mean (TM) using two-way ANOVA with Tukey's multiple comparison test (p<0.05). Results No differences among the different areas were detected in the MC group. For the Y-TZP and ICA groups, AS was statistically lower than both OS and TM. No differences in AS were observed among the groups. However, OS and TM showed significantly higher values for ICA and Y-TZP groups than MC group. Comparisons of ICA and Y-TZP revealed that OS was significantly lower for Y-TZP group, whereas no differences were observed for TM. Conclusions The total mean achieved by all groups was within the range of clinical acceptability. However, the metal-ceramic group demonstrated significantly lower values than the all-ceramic groups, especially in OS. PMID:22666843

  4. Internal fit of two all-ceramic systems and metal-ceramic crowns

    Directory of Open Access Journals (Sweden)

    Leandro Moura Martins

    2012-04-01

    Full Text Available OBJECTIVES: The aim of this study was to investigate the internal fit (IF of glass-infiltrated alumina (ICA - In-Ceram Alumina, yttria-stabilized tetragonal zirconia polycrystals (Y-TZP - IPS e.max ZirCAD, and metal-ceramic (MC - Ni-Cr alloy crowns. MATERIAL AND METHODS: Sixty standardized resin-tooth replicas of a maxillary first molar were produced for crown placement and divided into 3 groups (n=20 each according to the core material used (metal, ICA or Y-TZP. The IF of the crowns was measured using the replica technique, which employs a light body polyvinyl siloxane impression material to simulate the cement layer thickness. The data were analyzed according to the surfaces obtained for the occlusal space (OS, axial space (AS and total mean (TM using two-way ANOVA with Tukey ’s multiple comparison test (p<0.05. RESULTS: No differences among the different areas were detected in the MC group. For the Y-TZP and ICA groups, AS was statistically lower than both OS and TM. No differences in AS were observed among the groups. However, OS and TM showed significantly higher values for ICA and Y-TZP groups than MC group. Comparisons of ICA and Y-TZP revealed that OS was significantly lower for Y-TZP group, whereas no differences were observed for TM. CONCLUSIONS: The total mean achieved by all groups was within the range of clinical acceptability. However, the metal-ceramic group demonstrated significantly lower values than the all-ceramic groups, especially in OS.

  5. Influence of surface treatment and cyclic loading on the durability of repaired all-ceramic crowns

    Directory of Open Access Journals (Sweden)

    Ahmed Attia

    2010-04-01

    Full Text Available OBJECTIVE: This study investigated the durability of repaired all-ceramic crowns after cyclic loading. MATERIAL AND METHODS: Eighty In-ceram zirconia crowns were fabricated to restore prepared maxillary premolars. Resin cement was used for cementation of crowns. Palatal cusps were removed to simulate fracture of veneering porcelain and divided into 4 groups (n = 20. Fracture site was treated before repair as follows: roughening with diamond bur, (DB; air abrasion using 50 µm Al2O3, (AA and silica coating using Cojet system followed by silane application, (SC. Control group (CG 20 specimens were left without fracture. Palatal cusps were repaired using composite resin. Specimens were stored in water bath at 37ºC for one week. Ten specimens of each group were subjected to cyclic loading. Fracture load (N was recorded for each specimen using a universal testing machine. Two-way analysis of variance (ANOVA and Tukey honestly significant difference (HSD test (a=.05 were used for statistical analysis. RESULTS: There was statistically significant difference between control and tested groups, (p<0.001. Post Hoc analysis with the Tukey HSD test showed that cyclic loading fatigue significantly decreased means fracture load of control and test groups as follows (CG, 950.4±62.6 / 872.3±87.4, P = 0.0004, (DB, 624.2 ±38 / 425.5± 31.7, P <.001, (AA, 711.5 ±15.5 / 490 ± 25.2, p <0.001 and (SC, 788.7 ± 18.1 / 610.2 ± 25.2, P <.001, while silica coating and silane application significantly increased fracture load of repaired crowns (p<0.05. CONCLUSION: Repair of fractured In-ceram zirconia crowns after chairside treatment of the fracture site by silica coating and silane application could improve longevity of repaired In-ceram zirconia crowns.

  6. Fracture resistance of teeth restored with all-ceramic inlays and onlays: an in vitro study.

    Science.gov (United States)

    Saridag, S; Sevimay, M; Pekkan, G

    2013-01-01

    Fracture resistance of inlays and onlays may be influenced by the quantity of the dental structure removed and the restorative materials used. The purpose of this in vitro study was to evaluate the effects of two different cavity preparation designs and all-ceramic restorative materials on the fracture resistance of the tooth-restoration complex. Fifty mandibular third molar teeth were randomly divided into the following five groups: group 1: intact teeth (control); group 2: inlay preparations, lithium-disilicate glass-ceramic (IPS e.max Press, Ivoclar Vivadent AG, Schaan, Liechtenstein); group 3: inlay preparations, zirconia ceramic (ICE Zirkon, Zirkonzahn SRL, Gais, Italy); group 4: onlay preparations, lithium-disilicate glass-ceramic (IPS e.max Press); and group 5: onlay preparations, zirconia ceramic (ICE Zirkon). The inlay and onlay restorations were adhesively cemented with dual polymerizing resin cement (Variolink II, Ivoclar Vivadent AG). After thermal cycling (5° to 55°C × 5000 cycles), specimens were subjected to a compressive load until fracture at a crosshead speed of 0.5 mm/min. Statistical analyses were performed using one-way analysis of variance and Tukey HSD tests. The fracture strength values were significantly higher in the inlay group (2646.7 ± 360.4) restored with lithium-disilicate glass-ceramic than those of the onlay group (1673.6 ± 677) restored with lithium-disilicate glass-ceramic. The fracture strength values of teeth restored with inlays using zirconia ceramic (2849 ± 328) and onlays with zirconia ceramic (2796.3 ± 337.3) were similar to those of the intact teeth (2905.3 ± 398.8). In the IPS e.max Press groups, as the preparation amount was increased (from inlay to onlay preparation), the fracture resistance was decreased. In the ICE Zirkon ceramic groups, the preparation type did not affect the fracture resistance results.

  7. Biaxial flexural strength of Turkom-Cera core compared to two other all-ceramic systems

    Directory of Open Access Journals (Sweden)

    Bandar Mohammed Abdullah Al-Makramani

    2010-12-01

    Full Text Available Advances in all-ceramic systems have established predictable means of providing metal-free aesthetic and biocompatible materials. These materials must have sufficient strength to be a practical treatment alternative for the fabrication of crowns and fixed partial dentures. OBJECTIVES: The aim of this study was to compare the biaxial flexural strength of three core ceramic materials. MATERIAL AND METHODS: Three groups of 10 disc-shaped specimens (16 mm diameter x 1.2 mm thickness - in accordance with ISO-6872, 1995 were made from the following ceramic materials: Turkom-Cera Fused Alumina [(Turkom-Ceramic (M Sdn Bhd, Puchong, Selangor, Malaysia], In-Ceram (Vita Zahnfabrik, Bad Säckingen, Baden-Württemberg, Germany and Vitadur-N (Vita Zahnfabrik, Bad Säckingen, Baden-Württemberg, Germany, which were sintered according to the manufacturer's recommendations. The specimens were subjected to biaxial flexural strength test in an universal testing machine at a crosshead speed of 0.5 mm/min. The definitive fracture load was recorded for each specimen and the biaxial flexural strength was calculated from an equation in accordance with ISO-6872. RESULTS: The mean biaxial flexural strength values were: Turkom-Cera: 506.8±87.01 MPa, In-Ceram: 347.4±28.83 MPa and Vitadur-N: 128.7±12.72 MPa. The results were analyzed by the Levene's test and Dunnett's T3 post-hoc test (SPSS software V11.5.0 for Windows, SPSS, Chicago, IL, USA at a preset significance level of 5% because of unequal group variances (P<0.001. There was statistically significant difference between the three core ceramics (P<0.05. Turkom-Cera showed the highest biaxial flexural strength, followed by In-Ceram and Vitadur-N. CONCLUSIONS: Turkom-Cera core had significantly higher flexural strength than In-Ceram and Vitadur-N ceramic core materials.

  8. Influence of marginal fit and cement types on microleakage of all-ceramic crown systems

    Directory of Open Access Journals (Sweden)

    Ece Yüksel

    2011-06-01

    Full Text Available The purpose of this study was to evaluate the effects of both marginal fit and cementing with different luting agents on the microleakage of all-ceramic crown systems. Thirty-six extracted upper central incisors were prepared for full-coverage crowns and were divided into three groups. Group 1: CAD/CAM-fabricated ZrO2, Group 2: Heat-pressed lithium-disilicate, and Group 3: Cast Cr-Co copings as the control group. Copings were made following standard techniques, and groups were assigned cementation with either self-adhesive resin cement (A or glass-ionomer luting cement (B. The specimens were subjected to thermocycling, immersed in basic fuchsin solution, sectioned mesiodistally and buccolingually. The surface of each section was digitally photographed under a stereomicroscope. Microleakage was scored using a five-point scale, and the marginal gap was measured using image analysis software. Data were statistically analyzed using 2-way ANOVA, Kruskal-Wallis, and Mann-Whitney U tests (α: 0.05. The marginal discrepancy of each group was 82.7 ± 7 µm, 92.6 ± 4 µm and 96.5 ± 7 µm respectively. Group 1 showed significantly smaller gaps than Group 3 (P = 0.042. Self-adhesive resin cement (A showed a lower level of microleakage than glass-ionomer luting cement (B in all groups (P = 0.029. Microleakage scores of '0' were 83% for 1A, 50% for 1B, 50% for 2A, 16% for 2B, 33% for 3A and none for 3B. Marginal discrepancy and cement type both had significant effects on microleakage. Lower levels of microleakage were recorded with self-adhesive resin cement, while CAD/CAM-fabricated ZrO2 copings showed smaller marginal discrepancy and less microleakage in comparison to cast Cr-Co.

  9. Estimation of the reliability of all-ceramic crowns using finite element models and the stress-strength interference theory.

    Science.gov (United States)

    Li, Yan; Chen, Jianjun; Liu, Jipeng; Zhang, Lei; Wang, Weiguo; Zhang, Shaofeng

    2013-09-01

    The reliability of all-ceramic crowns is of concern to both patients and doctors. This study introduces a new methodology for quantifying the reliability of all-ceramic crowns based on the stress-strength interference theory and finite element models. The variables selected for the reliability analysis include the magnitude of the occlusal contact area, the occlusal load and the residual thermal stress. The calculated reliabilities of crowns under different loading conditions showed that too small occlusal contact areas or too great a difference of the thermal coefficient between veneer and core layer led to high failure possibilities. There results were consistent with many previous reports. Therefore, the methodology is shown to be a valuable method for analyzing the reliabilities of the restorations in the complicated oral environment.

  10. Full Contoured Tooth-Implant Supported 3-Pointic All-Ceramic Denture During Occlusal Load Transfer in Lateral Region

    Directory of Open Access Journals (Sweden)

    Żmudzki J.

    2016-06-01

    Full Text Available Implant and a tooth supported dentures are avoided by dentists because of uneven distribution of occlusal loads between a stiffer implant and a more pliable tooth. The hypothesis was that a 3-point all-ceramic bridge supported on a natural second premolar tooth and a two-pieces typical implant bears safely mastication loads. The finite element analysis showed that the implant splinted by all-ceramic zirconium bridge with the second premolar was safe under lateral mastication load, but there was found an overload at wide zone of bone tissue around the implant under the load of 800 N. The patients can safely masticate, but comminution of hard food should be avoided and they should be instructed that after such an indiscretion they need to contact a dental professional, because, in spite of integrity of the prosthesis, the bone tissue around the implant may fail and there is a hazard of intrusion of the tooth.

  11. Comparison of Fracture Toughness of All-Ceramic and Metal–Ceramic Cement Retained Implant Crowns: An In Vitro Study

    OpenAIRE

    Rao, S.; Chowdhary, R.

    2014-01-01

    To evaluate the fracture toughness of cement-retained implant-supported metal–ceramic molar crown with that of all-ceramic crowns, fabricated using IPS Empress 2 and yttria-stabilized zirconia copings. An dental implant and abutment was embedded in a clear polymethyl methacrylate model. A wax pattern reproducing the anatomy and dimension of a mandibular molar was made using inlay wax. Copings were made from the manufacturers guidelines for zirconia, metal ceramic and empress crown, in total o...

  12. Fit of zirconia all-ceramic crowns with different cervical margin designs, before and after porcelain firing and glazing.

    Science.gov (United States)

    Miura, Shoko; Inagaki, Ryoichi; Kasahara, Shin; Yoda, Masanobu

    2014-01-01

    The purpose of this study is to investigate the fit of zirconia cores and all-ceramic crowns prepared with different cervical margin designs. The radius of curvature between the axial wall and the occlusal surface was set to 1 mm in an abutment using the cervical shoulder marginal design (S) and to 0.2 and 0.5 mm in abutments with round shoulders (0.2RS and 0.5RS, respectively). The internal gaps of the cores were 45-138 μm (S), 41-141 μm (0.2RS), and 43-133 μm (0.5RS). The internal gaps of the all-ceramic crowns were 40-115 μm (S), 45-113 μm (0.2RS), and 42-126 μm (0.5RS). There were no significant differences in one-way ANOVA for any region in any marginal design before and after firing the porcelain. The marginal gaps between the all-ceramic crowns and dies were 27 ± 25 (S), 30 ± 29 (0.2RS), and 24 ± 27 μm (0.5RS), again with no significant differences in one-way ANOVA.

  13. Effect of pontic framework design on the fracture resistance of implant-supported all-ceramic fixed partial dentures

    Directory of Open Access Journals (Sweden)

    Ozgur Inan

    2009-10-01

    Full Text Available OBJECTIVE: The purpose of this study was to compare the fracture resistance of implant-supported all-ceramic fixed partial dentures, which have three different pontic designs. MATERIAL AND METHODS: Two implants were placed in a metal model simulating mandibular left second premolar and mandibular left second molar. Thirty standardized 3-unit all-ceramic fixed partial dentures with biconvex, convex or concave pontic designs were fabricated using IPS e.max system (n=10. Afterwards, specimens were centrally loaded on the pontics until failure with a universal testing machine. Results were analyzed by Kruskal-Wallis and Mann-Whitney U tests at 5% significance level. RESULTS: The fracture resistance values of all-ceramic fixed partial dentures designed with biconvex, convex or concave pontics were 349.71, 438.20 and 300.78 N, respectively. There were no statistically significant differences between the fracture resistances of the groups (p>0.05, except for convex and concave groups (p<0.05 and p=0.009, respectively. CONCLUSIONS: Convex design showed the best mechanical properties as demonstrated by the high values of fracture resistance.

  14. Effect of the shades of background substructures on the overall color of zirconia-based all-ceramic crowns

    OpenAIRE

    Suputtamongkol, Kallaya; Tulapornchai, Chantana; Mamani, Jatuphol; Kamchatphai, Wannaporn; Thongpun, Noparat

    2013-01-01

    PURPOSE The objective of this study was to determine the effect of the color of a background substructure on the overall color of a zirconia-based all-ceramic crown. MATERIALS AND METHODS Twenty one posterior zirconia crowns were made for twenty subjects. Seven premolar crowns and six molar crowns were cemented onto abutments with metal post and core in the first and second group. In the third group, eight molar crowns were cemented onto abutments with a prefabricated post and composite core ...

  15. Laser all-ceramic crown removal and pulpal temperature--a laboratory proof-of-principle study.

    Science.gov (United States)

    Rechmann, P; Buu, N C H; Rechmann, B M T; Finzen, F C

    2015-11-01

    The objective of this proof-of-principle laboratory pilot study was to evaluate the temperature increase in the pulp chamber in a worst case scenario during Er:YAG laser debonding of all-ceramic crowns. Twenty extracted molars were prepared to receive all-ceramic IPS E.max CAD full contour crowns. The crowns were bonded to the teeth with Ivoclar Multilink Automix. Times for laser debonding and temperature rise in the pulp chamber using micro-thermocouples were measured. The Er:YAG was used with 560 mJ/pulse. The irradiation was applied at a distance of 5 mm from the crown surface. Additional air-water spray for cooling was utilized. Each all-ceramic crown was successfully laser debonded with an average debonding time of 135 ± 35 s. No crown fractured, and no damage to the underlying dentin was detected. The bonding cement deteriorated, but no carbonization at the dentin/cement interface occurred. The temperature rise in the pulp chamber averaged 5.4° ± 2.2 °C. During 8 out of the 20 crown removals, the temperature rise exceeded 5.5 °C, lasting 5 to 43 s (average 18.8 ± 11.6 s). A temperature rise of 11.5 °C occurred only once, while seven times the temperature rise was limited to 6.8 ± 0.5 °C. Temperature rises above 5.5 °C occurred only when the laser was applied from one side and additional cooling from the side opposite the irradiation. Er:YAG laser energy can successfully be used to efficiently debond all-ceramic crowns from natural teeth. Temperature rises exceeding 5.5 °C only occur when an additional air/water cooling from a dental syringe is inaccurately directed. To avoid possible thermal damage and to allow further heat diffusion, clinically temperature-reduced water might be applied.

  16. Esthetic and endodontic management of fused maxillary lateral incisor and supernumerary teeth with all ceramic restoration after trauma

    Directory of Open Access Journals (Sweden)

    Kiranmeet Kaur Khurana

    2014-01-01

    Full Text Available Double or fusion of the teeth is a primary developmental anomaly union of two independently developing primary or permanent teeth. The tooth fusion may contribute to various significant problems such as crowding, caries and periodontal diseases. Fused teeth require an interdisciplinary approach combining the endodontic, esthetic and prosthetic treatments. All ceramic restoration meets the requirement of better appearance, biocompatibility and long life. By using restorative therapy esthetic and functional criteria were satisfied. Management of a case of fusion of a maxillary lateral incisor and a supernumerary tooth is presented.

  17. Clinical fit of all-ceramic three-unit fixed partial dentures, generated with three different CAD/CAM systems.

    Science.gov (United States)

    Reich, Sven; Wichmann, Manfred; Nkenke, Emeka; Proeschel, Peter

    2005-04-01

    In this study, the hypothesis was tested that the marginal and internal fit of CAD/CAM fabricated all-ceramic three-unit fixed partial dentures (FPDs) can be as good as in metal-ceramic FPDs. Twenty-four all-ceramic FPDs were fabricated and randomly subdivided into three equally sized groups. Eight frameworks were fabricated using the Digident CAD/CAM system (DIGI), another eight frameworks using the Cerec Inlab system (INLA). Vita Inceram Zirkonia blanks were used for both groups. In a third group frameworks were milled from yttrium-stabilized Zirconium blanks using the Lava system (LAVA). All frameworks were layered with ceramic veneering material. In addition, six three-unit metal-ceramic FPDs served as control group. All FPDs were evaluated using a replica technique with a light body silicone stabilized with a heavy body material. The replica samples were examined under microscope. The medians of marginal gaps were 75 microm for DIGI, 65 microm for LAVA and INLA and 54 microm for the conventional FPDs. Only the DIGI data differed significantly from those of the conventional FPDs. Within the limits of this study, the results suggest that the accuracy of CAD/CAM generated three-unit FPDs is satisfactory for clinical use.

  18. All-ceramic prosthetic rehabilitation of a worn dentition: Use of a distal cantilever. Two-year follow-up

    Directory of Open Access Journals (Sweden)

    Usama N Chekhani

    2013-01-01

    Full Text Available The rehabilitation of heavily abraded occlusion in patients with parafunctional habits is a restorative challenge to the dentist. Use of all-ceramic systems in such cases is widely considered, but uncertainty over their resistance hinders their broad use. The authors would like to illustrate a possible approach by mixing two all-ceramic systems based on zirconium dioxide and lithium disilicate. A 48-year-old female patient attended with reduced vertical dimension in a full dentition. She suffered from craniomandibular (CMD pain and desired an esthetic rehabilitation. Prosthodontic treatment was started in a pain-free condition, after correction of the vertical dimension with an occlusal splint, over four months. Determination of the treatment was based on the clinical findings: IPS e.max® ZirCAD frameworks veneered with IPS e.max® Ceram were used for discolored retainers or subgingival finishing lines. All the rest received IPS e.max® Press crowns. A zirconia-based, single-tooth-retained distal cantilever reconstruction was used to replace a missing second molar. No technical or biological complication was observed 24 months after treatment. The patient was highly satisfied and pain-free.

  19. Optimizing the design of bio-inspired functionally graded material (FGM) layer in all-ceramic dental restorations.

    Science.gov (United States)

    Cui, Chang; Sun, Jian

    2014-01-01

    Due to elastic modulus mismatch between the different layers in all-ceramic dental restorations, high tensile stress concentrates at the interface between the ceramic core and cement. In natural tooth structure, stress concentration is reduced by the functionally graded structure of dentin-enamel junction (DEJ) which interconnects enamel and dentin. Inspired by DEJ, the aim of this study was to explore the optimum design of a bio-inspired functionally graded material (FGM) layer in all-ceramic dental restorations to achieve excellent stress reduction and distribution. Three-dimensional finite element model of a multi-layer structure was developed, which comprised bilayered ceramic, bio-inspired FGM layer, cement, and dentin. Finite element method and first-order optimization technique were used to realize the optimal bio-inspired FGM layer design. The bio-inspired FGM layer significantly reduced stress concentration at the interface between the crown and cement, and stresses were evenly distributed in FGM layer. With the optimal design, an elastic modulus distribution similar to that in DEJ occurred in the FGM layer.

  20. Marginal and internal fit of all-ceramic crowns fabricated with two different CAD/CAM systems.

    Science.gov (United States)

    Lee, Kyu-Bok; Park, Charn-Woon; Kim, Kyo-Han; Kwon, Tae-Yub

    2008-05-01

    This study evaluated the accuracy of marginal and internal fit between the all-ceramic crowns manufactured by a conventional double-layer computer-aided design/computer-aided manufacturing (CAD/CAM) system and a single-layer system. Ten standardized crowns were fabricated from each of these two systems: conventional double-layer CAD/CAM system (Procera) and a single-layer system (Cerec 3D). The copings and completed crowns were seated on the abutments by a special device that facilitated uniform loading, and the marginal discrepancies were measured. Internal gaps were also measured using a low-viscosity silicone material. Marginal discrepancies of Procera copings were significantly smaller than those of Procera crowns and Cerec 3D crowns (p 0.05). On internal gaps, Cerec 3D crowns showed significantly larger internal gaps than Procera copings and crowns (p system demonstrated acceptable marginal and internal fit.

  1. Esthetic restoration of infra-occluded retained primary mandibular incisors with all-ceramic crowns in adult dentition.

    Science.gov (United States)

    Hsu, Kuang-Wei; Shen, Yu-Fu

    2004-12-01

    The prevalence of hypodontia is reported to be between 1.5% to 10% in the permanent dentition. In the anterior teeth, maxillary lateral incisors and mandibular central incisors are the most frequently involved teeth. This causes esthetic problems for the patient. Several reports have focused on restoration of retained maxillary primary anterior teeth, but none have described restoration of retained mandibular primary incisors. This clinical report describes the restoration of infra-occluded retained primary mandibular central incisors of a 17 year-old girl diagnosed with hypodontia. All-ceramic crowns made with computer-aided design/ computer-aided manufacturing technology were used to restore the teeth incisally and interproximally. Due to a relatively short root length and inadequate crown-root ratio, the primary mandibular central incisors were splinted and adjusted to distribute the protrusive force evenly across the maxillary and mandibular incisors. Functional and esthetic results were achieved.

  2. Effect of Taper on Stress Distribution of All Ceramic Fixed Partial Dentures: a 3D-FEA Study

    Directory of Open Access Journals (Sweden)

    F. Gerami-Panah

    2005-09-01

    Full Text Available Statement of Problem: Mechanical failure of ceramic materials is controlled by brittle fracture, mostly occurred in tension. In 3-unit all-ceramic FPDs the connector area is considered to be at fracture risk because of tensile stress concentrations.Purpose: The aim of this FE analysis was to evaluate the effect of taper on stress distribution in all-ceramic FPDs.Materials and Methods: In this experimental study two 3-D finite element models of thee-unit IPS-Empress 2 FPDs replacing mandible second premolar were created by means of finite element software. The digital images were obtained from CT scan of human skull. Abutment was reduced with 12 and 22 degrees of taper. The cement layer,PDL, cancellous bone and cortical bone were also modeled. Frameworks of core material were fabricated. A static load of 100 N was applied at mid pontic area.Resolved stresses were calculated according to the Von Mises criterion and principal stresses.Results: In both models stresses were concentrated at the connectors. The maximum stresses were lower in the model with larger taper. The maximum Von Mises stress was recorded at the connector region of the premolar and the pontic. In model with larger taper the patterns of stresses were also more distributed and less concentrated.Conclusion: The highest Von Mises and principal stress were recorded at the connectors. Tensile stresses developed at the gingival connector of premolar and pontic was higher than molar. The stress level in model with 22-degree taper was lower compare to 12-degree and the stress pattern was more distributed, lowered the risk ofconcentrations.

  3. 全瓷修复材料的老化性研究%Research on the Aging of All-ceramics Restoration Materials

    Institute of Scientific and Technical Information of China (English)

    张东姣

    2011-01-01

    全瓷修复材料以良好的美学特性、生物相容性和机械性能在临床上得到了广泛的应用,但全瓷冠桥在复杂的口腔环境下常出现老化现象,致使全瓷材料的颜色及机械性能产生变化.研究全瓷材料的老化现象及其规律可为临床全瓷冠桥的可靠性和耐久性评价及其改进提供有效的理论依据.本文就全瓷材料的老化现象对其颜色和机械性能的影响及影响老化的因素作一综述和评价.%All-ceramic crowns and bridges have been widely used for dental restorations owing to their excellent func-tionalityt aesthetics and biocompatibility. However, the premature clinical failure of all-ceramic crowns and bridges may easily occur when they are subjected to the complex environment of oral cavity. In the oral environment, all-ceramic materials are prone to aging. Aging can lead all-ceramic materials to change color, to lower bending strength, and to reduce anti-fracture toughness. There are many factors affecting the aging of the all-ceramic materials, for example, the grain size, the type of stabilizer, the residual stress and the water environment. In order to analyze the aging behavior, to optimize the design of all-ceramic crowns and bridges, and to evaluate the reliability and durability, we review in this paper recent research progress of aging behavior for all-ceramics restoration materials.

  4. Influence of sodalite zeolite infiltration on the coefficient of thermal expansion and bond strength of all-ceramic dental prostheses.

    Science.gov (United States)

    Naji, Ghassan Abdul-Hamid; Omar, Ros Anita; Yahya, Rosiyah

    2017-03-01

    In all-ceramic systems, a high incidence of veneer chip-off has been reported in clinical studies. Coefficient of thermal expansion (CTE) behaviour is one of the factors that may increase residual stress in the interface and influence the veneer/core bond strength. Therefore, this study aimed to evaluate the effect of sodalite zeolite-infiltration on the CTE behaviour and bond strength of different all-ceramic prostheses. The case-study groups were synthesized sodalite zeolite-infiltrated alumina (IA-SOD) and synthesized sodalite zeolite-infiltrated zirconia-toughened alumina (ZTA) (IZ-SOD), while the control groups were glass-infiltrated alumina (IA-glass) and glass-infiltrated ZTA (IZ-glass). Forty cylindrical-shaped samples measuring 5 mm in diameter and 10 mm in height were tested for CTE using a thermo-mechanical analyser machine, and forty disc-shaped ceramic samples measuring 12 mm in diameter and 1.2 ± 0.2 mm in thickness were prepared using specially designed stainless steel split mould and veneered by cylinder-shaped (2 mm high × 2 mm diameter) low-fusing porcelain (Vita VM7). The veneer/core samples were sintered and tested for shear bond strength using a high precision universal testing machine. Scanning electron microscope, stereo microscope, atomic force microscope, and energy-dispersive X-ray spectroscopy were used to investigate the structural characteristics of samples at the fracture surface. The collected data were analyzed with a one-way ANOVA and Tukey HSD test (α=.05). IZ-SOD revealed highest CTE and shear bond strength values, while the IA-glass revealed the lowest values than the other groups. There was no significant difference in CTE and bond strength among IZ-SOD, IA-SOD and IZ-glass samples (p>0.05). The experimental SOD zeolite-infiltrated samples revealed higher CTE mismatch and bond strength along with a more favourable mode of failure than did the commercial glass-infiltrated samples. Sandblast technique is considered as effective

  5. The reproducibility and accuracy of internal fit of Cerec 3D CAD/CAM all ceramic crowns.

    LENUS (Irish Health Repository)

    D'Arcy, Brian L

    2009-06-01

    The objective of this study was to evaluate the reproducibility and accuracy of internal fit using Cerec 3D CAD\\/CAM (computer aided design\\/computer aided manufacturing) all-ceramic crowns and to investigate the proximal contact point areas between the crowns and neighbouring teeth, in terms of location and the presence or absence of contact. A total of 48 crowns were milled and divided into two groups of twenty-four each. One group consisted of testing a Control die and the other group consisted of testing single Replica stone die duplicates of the Control die. The Internal Marginal Gap, Axio-Occlusal Transition Gap and Occlusal Gap were measured on each crown in both groups. No significant differences were identified between the mean thickness of the Marginal Gap, the Axio-Occlusal Transition Gap and the Occlusal Gap of the Control die when compared with the Replica dies indicating uniformity and consistency of the accuracy of fit and therefore die replication.

  6. Load-bearing capacity of all-ceramic posterior four-unit fixed partial dentures with different zirconia frameworks.

    Science.gov (United States)

    Kohorst, Philipp; Herzog, Timo J; Borchers, Lothar; Stiesch-Scholz, Meike

    2007-04-01

    The aim of this in vitro study was to compare the load-bearing capacity of posterior four-unit fixed partial dentures (FPDs) produced with two different yttria-stabilized polycrystalline tetragonal zirconia (Y-TZP) ceramics, one being a presintered material, the other a fully sintered, hot isostatically pressed material. Additionally, as a novel approach, the influence of preliminary mechanical damage upon the fracture force of an FPD has been investigated. A total of 20 frameworks each were milled from presintered zirconia and from fully sintered zirconia. Prior to veneering, 10 frameworks of each material were 'damaged' by a defined saw cut similar to an accidental flaw generated during shape cutting. Before fracture testing, all FPDs were subjected to thermal and mechanical cycling. Additionally, scanning electron microscopy was used to investigate fracture surfaces. Statistical analysis showed that FPDs milled from fully sintered zirconia had a significantly higher fracture resistance compared with specimens made from presintered material, whereas preliminary damage did not have a significant effect. After aging, FPDs made from both materials were capable of withstanding occlusal forces reported in the literature. Therefore, both types of Y-TZP may be suitable for posterior four-unit all-ceramic FPDs, although further prolonged aging experiments and prospective clinical trials are required to prove their fitness for clinical use.

  7. Advancements in all-ceramics for dental restorations and their effect on the wear of opposing dentition

    Science.gov (United States)

    Rashid, Haroon; Sheikh, Zeeshan; Misbahuddin, Syed; Kazmi, Murtaza Raza; Qureshi, Sameer; Uddin, Muhammad Zuhaib

    2016-01-01

    Tooth wear is a process that is usually a result of tooth to tooth and/or tooth and restoration contact. The process of wear essentially becomes accelerated by the introduction of restorations inside the oral cavity, especially in case of opposing ceramic restorations. The newest materials have vastly contributed toward the interest in esthetic dental restorations and have been extensively studied in laboratories. However, despite the recent technological advancements, there has not been a valid in vivo method of evaluation involving clinical wear caused due to ceramics upon restored teeth and natural dentition. The aim of this paper is to review the latest advancements in all-ceramic materials, and their effect on the wear of opposing dentition. The descriptive review has been written after a thorough MEDLINE/PubMed search by the authors. It is imperative that clinicians are aware of recent advancements and that they should always consider the type of ceramic restorative materials used to maintain a stable occlusal relation. The ceramic restorations should be adequately finished and polished after the chair-side adjustment process of occlusal surfaces. PMID:28042280

  8. Basic Finite Element Analysis of Para-periodontal Ligament in All-ceramic Zirconia Fixed Partial Denture.

    Science.gov (United States)

    Nomoto, Syuntaro; Matsunaga, Satoru; Sato, Toru; Yotsuya, Mamoru; Abe, Shinichi

    2015-01-01

    The purpose of the present study was to investigate the validity of incorporating a para-periodontal ligament in the test mold used in a basic fracture test of a zirconia all-ceramic fixed partial denture (FPD). A simplified three-dimensional finite element analysis model was designed based on the three-unit FPD fracture test. Two types of model, one with and one without a para-periodontal ligament between the abutment and base mold, were fabricated. Microfocus CT of the missing first molar area in a dry human mandible was performed. A three-dimensional model was then fabricated based on the data obtained. A load of 600 N was applied to the center of the pontic and stress distribution observed. The model with the para-periodontal ligament showed stress dispersion to the dental root with rotation of the abutment mold. Stress distribution in the finite element analysis model with a para-periodontal ligament showed greater similarity with that in the mandibular model than with that in the other two models without a para-periodontal ligament.

  9. Adhesive luting of all-ceramic restorations--the impact of cementation variables and short-term water storage on the strength of a feldspathic dental ceramic.

    LENUS (Irish Health Repository)

    Addison, Owen

    2008-08-01

    To investigate the impact of resin cement luting variables and short-term water storage on the strength of an adhesively luted all-ceramic restorative material. An understanding of the strengthening mechanisms will result in optimisation of operative techniques and materials selection criteria.

  10. OPTIMAL PREPARATION JUNCTIONS FOR ALL-CERAMIC FIXED RESTORATIONS MADE BY CAM 5 – S 2 IMPRESSION, VHF

    Directory of Open Access Journals (Sweden)

    Angelina Vlahova

    2015-12-01

    Full Text Available Introduction: The type of the preparation junction is determined by a number of factors that need to be taken in consideration with CAD/CAM Fixed Prosthodontics: the material of which the construction will be made; the type and condition of the retainer teeth, of their periodontium and the occlusion; the design software, the CAM setting and the type of drills; the working protocol; the type of the cement and the method of cementation.Purpose: The aim of this publication is to describe the optimal preparation junctions for all-ceramic crown and bridge restorations made by CAM 5 - S 2 Impression, VHF.Materials and methods: Suitable are chamfer and shoulder preparation junction with rounded inner angle (width 1 - 1, 5 mm. Trimming of 1.5 – 2 mm dental tissues is necessary on the occlusal surface. The homothetic reduction of teeth is optimal.Results and discussion: The width depends on the size and vitality of the tooth. In stained teeth and those built with metal pins the removal of more tissues provides a greater volume needed to disguise the dark color. Vestibular preparation under the level of the gingiva is preferable to ensure optimal aesthetics. Preparation junction is determined also by the CAD/CAM technology - the type of drills and protocol of impression taking (classical or digital. The creation of a working model with TRIOS, 3Shape intraoral scanner is greatly facilitated by preparation junctions made above the gingival margin.Conclusion: Knowledge about the criteria for selection the preparation junctions is essential for fabrication accurate and aesthetic CAD/CAM restorations.

  11. Effects of surface-conditioning methods on shear bond strength of brackets bonded to different all-ceramic materials.

    Science.gov (United States)

    Saraç, Y Şinasi; Külünk, Tolga; Elekdağ-Türk, Selma; Saraç, Duygu; Türk, Tamer

    2011-12-01

    The aims of this study were to investigate the effects of two surface-conditioning methods on the shear bond strength (SBS) of metal brackets bonded to three different all-ceramic materials, and to evaluate the mode of failure after debonding. Twenty feldspathic, 20 fluoro-apatite, and 20 leucite-reinforced ceramic specimens were examined following two surface-conditioning methods: air-particle abrasion (APA) with 25 μm Al(2)O(3) and silica coating with 30 μm Al(2)O(3) particles modified by silica. After silane application, metal brackets were bonded with light cure composite and then stored in distilled water for 1 week and thermocycled (×1000 at 5-55°C for 30 seconds). The SBS of the brackets was measured on a universal testing machine. The ceramic surfaces were examined with a stereomicroscope to determine the amount of composite resin remaining using the adhesive remnant index. Two-way analysis of variance, Tukey's multiple comparison test, and Weibull analysis were used for evaluation of SBS. The lowest SBS was with APA for the fluoro-apatite ceramic (11.82 MPa), which was not significantly different from APA for the feldspathic ceramic (13.58 MPa). The SBS for the fluoro-apatite ceramic was significantly lower than that of leucite-reinforced ceramic with APA (14.82 MPa). The highest SBS value was obtained with silica coating of the leucite-reinforced ceramic (24.17 MPa), but this was not significantly different from the SBS for feldspathic and fluoro-apatite ceramic (23.51 and 22.18 MPa, respectively). The SBS values with silica coating showed significant differences from those of APA. For all samples, the adhesive failures were between the ceramic and composite resin. No ceramic fractures or cracks were observed. Chairside tribochemical silica coating significantly increased the mean bond strength values.

  12. Comparison of fracture toughness of all-ceramic and metal-ceramic cement retained implant crowns: an in vitro study.

    Science.gov (United States)

    Rao, S; Chowdhary, R

    2014-12-01

    To evaluate the fracture toughness of cement-retained implant-supported metal-ceramic molar crown with that of all-ceramic crowns, fabricated using IPS Empress 2 and yttria-stabilized zirconia copings. An dental implant and abutment was embedded in a clear polymethyl methacrylate model. A wax pattern reproducing the anatomy and dimension of a mandibular molar was made using inlay wax. Copings were made from the manufacturers guidelines for zirconia, metal ceramic and empress crown, in total of 21 copings, which were built for the crowns with metal layering ceramics specified by the manufacturers. The polymethylmethacrylate block-implant abutment complex was mounted on universal testing machine, and a static continuos vertical compressive load with a crosshead speed of 0.5 mm/min was applied. The breaking load and the peak load (in kilo Newtons) were recorded. The fractures for group I (zirconia-ceramic) and group II (metal-ceramic) occurred on the mesio-buccal aspect of the crowns involving the veneered ceramic layer while the catastrophic/bulk fracture was not observed. The mean value of breaking load for zirconia-ceramic, metal-ceramic and IPS-empress 2 was 3.4335, 3.071 and 1.0673 kN respectively. The mean value of peak load for zirconia-ceramic, metal-ceramic and IPS-empress 2 was 4.7365, 3.2757 and 1.566 kN respectively. It can be concluded that the zirconia-ceramic crown with the fracture toughness of 4.7365 ± 2.2676 kN has sufficient strength to allow clinical testing of these crowns as an alternative for metal-ceramic crowns (3.2757 ± 0.4681 kN).

  13. Mechanical Properties of a new Dental all-ceramic Material-zirconia Toughened Nanometer-ceramic Composite

    Institute of Scientific and Technical Information of China (English)

    CHAI Feng; XU Ling; CHAO Yong-lie; LIAO Yun-mao; ZHAO Yi-min

    2003-01-01

    Objectives:All-ceramic dental restorations are attractive to the dental community because of their advantages.But they're also challenged by relatively low flexural strength and intrinsic poor resistance to fracture.This paper aims to investigate mechanical properties of a new dental all-ceramic material, i.e. zirconia toughened nanometer-ceramic composite (α-Al2O3/nZrO2).Methods:α-Al2O3/nZrO2 ceramics powder (W) was processed with combined methods of chemical co-precipitation method and ball milling. Scanning electron microscopy (SEM)was used to determine the particle size distribution and to characterize the particle morphology of the powders. Four kinds of powders with different ZrO2 content (5wt%, 10wt%, 15wt% and 20wt%) were prepared by using α-Al2O3 powder to dilute the higher ZrO2 content powder (W). The ceramic matrix compacts were made by slip-casting technique and sintering to 1 200~1 600 ℃. The flexural strength and the fracture toughness of the matrix materials were measured via three-point bending test and single-edge notch beam methods, respectively.Results:1) The particle distribution of the Al2O3/nZrO2 powder ranged from 0.02~3.0 μm, with the superfine particles almost accounting for 20%;2) There is a significant difference of flexural strength (P<0.05) between the groups with 1 450 ℃ and 1 600 ℃ sintering temperature and 1 200 ℃;3) There is a significant difference of flexural strength (P<0.05) between different zirconia volume fraction groups with the same sintering temperature, the ceramic matrix samples with higher nZrO2 (W) content had much better mechanical properties than those of pure α-Al2O3 ceramics.Conclusions:The studied nanometer α-Al2O3/nZrO2 powder was homogeously distributed within the matrix and had reasonable powder-size gradation to improve mechanical properties of ceramics.%目的:口腔全瓷修复体以其独特优越性受到医患青睐,但脆性问题一直限制其应用范围及使用可靠性.本研

  14. Prospective clinical split-mouth study of pressed and CAD/CAM all-ceramic partial-coverage restorations: 7-year results.

    Science.gov (United States)

    Guess, Petra C; Selz, Christian F; Steinhart, Yann-Niclas; Stampf, Susanne; Strub, Joerg R

    2013-01-01

    The aim of this prospective clinical split-mouth study was to investigate the longterm performance of pressed and computer-aided design/computer-assisted manufacture (CAD/CAM) all-ceramic partial-coverage restorations (PCRs). Twentyfive patients were restored with 40 lithium disilicate pressed PCRs (IPS e.max-Press, Ivoclar Vivadent) and 40 leucite-reinforced glass-ceramic CAD/CAM PCRs (ProCAD, Ivoclar Vivadent). All restorations were placed in vital first or second molars. The 7-year Kaplan-Meier survival rate was 100% for pressed PCRs and 97% for CAD/ CAM PCRs. Both systems showed significant deterioration over time in all modified United States Public Health Service criteria. Increased surface roughness and impaired color match were significantly more prevalent with pressed PCRs. Based on the 7-year data, both all-ceramic systems can be considered reliable treatment options for posterior PCRs.

  15. Influence of all-ceramic and porcelain-fused-to-metal restorations on peri-implant gingival discoloration:a spectrophotometric comparison

    DEFF Research Database (Denmark)

    Peng, Min; Fei, Wei; Hosseini, Mandana

    2013-01-01

    PURPOSE: To compare the gingival discoloration of implant supported all-ceramic and Porcelain-Fused-to-Metal (PFM) restorations in anterior maxillary region by spectrophotometric evaluation. METHODS: Eighteen patients with 29 implant-supported single crowns (11 all-ceramic restorations, 9 PFM...... restorations with titanium abutment and 9 PFM restorations with gold alloy abutment) in anterior maxillary area were recruited. The color difference between peri-implant gingival and contra-lateral/neighboring tooth mucosa were assessed using a spectrophotometer in CIELab coordinates. Subjective gingival...... restorations with titanium abutment (3.5+2.5) as regard to spectrophotometric evaluation of gingival discoloration, and no significant difference was found between the PFM restorations with titanium abutment and PFM restorations with gold alloy abutment (6.3+3.8) either. There was, however, significant...

  16. 二氧化锆全瓷冠对牙龈健康的影响%Effect of zirconia all-ceramic crowns on gingival health

    Institute of Scientific and Technical Information of China (English)

    张非煜; 吕亚林; 董坚; 李俨; 张伟; 李国庆

    2013-01-01

    Objective To compare the effect of anterior teeth clinical restoration with zirconia all-ceramic crowns and cast all-ceramic crowns.Methods All 49 patients with 73 crowns were enrolled in zirconia group.Those anterior teeth were restored with zirconia all-ceramic crowns.The control group were selected with 32 crowns from 25 patients with cast all-ceramic crowns.One day,3 months,6 months,1 year after restoration were the time points.Marginal integrity was observed according to the standards specified by the Califcrnia Dental Association.Results All 73 zirconia ceramic crowns repairs were completed on day 1 and 3 months,6 months after restoration in zirconia group.72 anterior teeth got grade Ⅰ,1 anterior tooth got grade Ⅱ ; 1 year after the repair,70 anterior teeth got grade Ⅰ and 3 anterior teeth got grade Ⅱ.All 32 casting all-ceramic crowns restorations were completed in one day,3 months,6 months,1 year after the restoration.31 anterior teeth got grade Ⅰ,1 anterior teeth got grade Ⅱ.The clinical effects of the two types of all-ceramic crown showed no statistical difference.Conclusion Zirconia all ceramic crown has the similar gingival effect as the cast all-ceramic crowns and both of those kinds of restorations are ideal for anterior teeth repair.%目的 分析前牙美容修复中二氧化锆全瓷冠对牙龈健康的影响.方法 49例患者共73颗前牙采用二氧化锆全瓷冠修复,设为二氧化锆组;对照组选择25例患者共32颗前牙采用铸造全瓷冠修复.分别在修复后1d和3、6、12个月参照美国加利福尼亚州牙科协会制定的标准,观察牙龈健康状况.结果 二氧化锆组在修复完成第1天及第3、6个月时,牙龈健康分级Ⅰ、Ⅱ级均分别为72、1颗;修复后12个月,Ⅰ、Ⅱ级分别为70、3颗.对照组在修复完成第1天及第3、6、12个月时,牙龈健康分级Ⅰ、Ⅱ级均分别为72、1颗.2种全瓷冠的临床效果差异无统计学意义(P>0.05).结论 二氧化

  17. The Advantage of Intraoral Digital Impressions on All-ceramic Crowns%口内数字印模用于全瓷冠修复的优势

    Institute of Scientific and Technical Information of China (English)

    房磊; 陈萌萌; 孙越; 张春霞; 肖威娜

    2016-01-01

    To study the advantages of intraoral digital impression in the preparation of all ceramic crowns. 2014 and 2015 in the hospital, Department of Stomatology, the requirements of all ceramic single crown repair of 40 patients with, a total of 40 teeth teeth, were divided to two groups, with 20 cases in each group, 20 teeth, respectively, to take the traditional impression way for preparing gypsum model and intraoral digital impression made digital impression, make all ceramic crown in the restoration of teeth respectively, to observe and record operating time of the two groups all ceramic crown on the edge of the dense degree and production model, two groups compared to determine the advantages of digital impression. The two groups all ceramic crown edge sealing degree can group the success rate is better than the traditional digital impression impression group. The digital impression group operation time is much shorter than the traditional impression group is obviously superior to the traditional model. Intraoral digital impression in all ceramic crown preparation has obvious advantages, high precision, and to save time, materials, and improve the comfort degree of patients satisfaction.%为研究口内数字印模在全瓷冠修复方面的应用优势,选取2014年1月———2015年5月,在本院口腔科就诊要求全瓷单冠修复的患者40人、共40颗牙齿,随机分为a、b两组,每组20人、20颗牙齿,a组采取传统印模方式制取石膏模型,b组采用口内数字印模方式取得数字化印模,分别制作全瓷冠修复牙齿,观察记录两组全瓷冠边缘的密合程度及制取模型所用的操作时间,两组比较,以判断数字印模的优势。发现两组全瓷冠边缘的密合程度均可,数字印模组成功率优于传统印模组。数字印模组操作时间大大短于传统印模组,明显优于传统印模组。说明口内数字印模在全瓷冠制取方面有明显优势,精准度高且

  18. 个别牙位全瓷冠的美学仿真修复%Application of Aesthetic Principles in Single-unit all Ceramic Restorations

    Institute of Scientific and Technical Information of China (English)

    陈晨; 章非敏; 谢海峰

    2012-01-01

    Objective: To evaluate effects of applications of aesthetic principle in all - ceramic single-unit restorations. Method; Shade guide was used in color matching. In addition, portraying tooth shade pictures or recording the digital tooth images were performed to make technicians comprehend the aims of doctors and patients completely. Result: All the all-ceramic restorations achieved good aesthetic results. Conclusion: Applying aesthetic principles correctly and comunicating with technicians well would contribute to improving clinic success of single-unit all ceramic restorations aesthetically.%目的:探讨个别牙位全瓷冠的美学仿真修复要点和临床注意事项.方法:在明确患者要求的前提下,对拟进行个别牙位全瓷冠修复的病例综合采用比色板比色、绘制比色图、记录个性特征、拍摄数码照片等方式,制作全瓷修复体.拍摄修复前后的数码照片进行美学评价.结果:所有患者的全瓷冠临床美学修复效果良好.结论:灵活运用美学原理,综合借助多种方式进行有效的医技沟通,有助于重建出美观、富有个性特征的全瓷修复体.

  19. CAD/CAM Zirconia vs. slip-cast glass-infiltrated Alumina/Zirconia all-ceramic crowns: 2-year results of a randomized controlled clinical trial

    OpenAIRE

    Murat Cavit Çehreli; Ali Murat Kökat; Kivanç Akça

    2009-01-01

    The aim of this randomized controlled clinical trial was to compare the early clinical outcome of slip-cast glass-infiltrated Alumina/Zirconia and CAD/CAM Zirconia all-ceramic crowns. A total of 30 InCeram® Zirconia and Cercon® Zirconia crowns were fabricated and cemented with a glass ionomer cement in 20 patients. At baseline, 6-month, 1-year, and 2-year recall appointments, Californian Dental Association (CDA) quality evaluation system was used to evaluate the prosthetic replacements, and p...

  20. All-ceramic single-tooth restorations: choosing the material to match the preparation--preparing the tooth to match the material.

    Science.gov (United States)

    Baltzer, A

    2008-01-01

    The shape of a crown preparation is the prime determinant for the choice of material for an all-ceramic restoration. One essential factor is the available space for the restoration, which requires a certain occlusal thickness. The dentist's preparation design determines the available vertical clearance, and the dental technician has the responsibility of advising the dentist with regard to either choosing the right material to match the preparation or to preparing the tooth to match the material. Assuming a minimum static fracture strength of > 2000 N, the following materials can be used for all-ceramic crowns: Laboratory surveys have shown that in most situations, the available occlusal clearance in clinical reality is only 0.8 to 0.9 mm (after cementing). This shows that the available space will often be insufficient for providing monoblock crowns and still on the tight side for veneered oxide ceramics (In Ceram, zirconia, etc.). However, crowns made of veneered oxide ceramics are much more complex to fabricate and much more expensive. By simply providing a minimal occlusal thickness of 1.5 mm, the treatment provider could therefore easily facilitate the use of the much more economical monoblock crowns without compromising either esthetics or strength. Actually, crowns with veneered oxide ceramic copings do not offer any higher fracture resistance compared to Mark II crowns as long as the minimum thickness requirements are met. The flexural strength of CAD/CAM-fabricated lithium disilicate rods is about twice that of CAD/CAM-fabricated Mark II rods. When used for crowns with a wall thickness of 1.5 mm, however, both materials exhibit the same fracture strength of between 2000 and 2500 N. This is related to the different reinforcing action of the adhesive luting agent, which is essentially required for both these materials. When choosing a material, preparation shapes, technical complexity and cost should be thoroughly compared and scrutinized and should figure

  1. The Evolution and Fabrication of Implant-supported Full-arch Hybrid Prostheses. From Conventional Casted Metal to an All-Ceramic Zirconia.

    Science.gov (United States)

    Ouzer, Amanda

    2015-11-01

    Implant-supported, full-arch hybrid prostheses have developed from cast-metal frameworks with acrylic or porcelain to all-ceramic zirconia frameworks. CAD/CAM manufacturing removed the inaccuracies seen with casting and made use of zirconia possible. The materials and processes for prosthodontic fabrication are explained. Zirconia is highly opaque and versatile. However, porcelain-veneered zirconia frameworks have shown higher enamel wear, among other problems. Lithium disilicate has been shown to be more translucent than zirconia. Improved stained and more translucent zirconia frameworks have been produced as well. These promising new methods have gained popularity, but long-term studies are scarce and, thus, more research is required.

  2. An interdisciplinary approach to reconstruct a fractured tooth under an intact all ceramic crown: Case report with four years follow up

    Directory of Open Access Journals (Sweden)

    Sudhir Bhandari

    2011-01-01

    Full Text Available Trauma causing the fracture of a restored tooth with the extracoronal full coverage prosthesis remaining intact is a common occurrence in dental practice. Reconstruction of the damaged tooth foundation and recementation of the crown can pose quite a challenge for the restorative dentist. This case report describes an innovative interdisciplinary chairside technique for the recementation of an all-ceramic crown on a fractured maxillary central incisor. The course of care described is effective, affordable, and saves time in comparison with other treatment options for such clinical situations.

  3. All-Ceramic Single Crown Restauration of Zirconia Oral Implants and Its Influence on Fracture Resistance: An Investigation in the Artificial Mouth

    Directory of Open Access Journals (Sweden)

    Ralf-Joachim Kohal

    2015-04-01

    Full Text Available The aim of the current investigation was to evaluate the fracture resistance of one-piece zirconia oral implants with and without all-ceramic incisor crowns after long-term thermomechanical cycling. A total of 48 implants were evaluated. The groups with crowns (C, 24 samples and without crowns (N, 24 samples were subdivided according to the loading protocol, resulting in three groups of 8 samples each: Group “0” was not exposed to cyclic loading, whereas groups “5” and “10” were loaded with 5 and 10 million chewing cycles, respectively. This resulted in 6 different groups: C0/N0, C5/N5 and C10/N10. Subsequently, all 48 implants were statically loaded to fracture and bending moments were calculated. All implants survived the artificial aging. For the static loading the following average bending moments were calculated: C0: 326 Ncm; C5: 339 Ncm; C10: 369 Ncm; N0: 339 Ncm; N5: 398 Ncm and N10: 355 Ncm. To a certain extent, thermomechanical cycling resulted in an increase of fracture resistance which did not prove to be statistically significant. Regarding its fracture resistance, the evaluated ceramic implant system made of Y-TZP seems to be able to resist physiological chewing forces long-term. Restauration with all-ceramic single crowns showed no negative influence on fracture resistance.

  4. Selection and application of oral all-ceramic crown materials%口腔全瓷冠修复材料的选择及应用

    Institute of Scientific and Technical Information of China (English)

    程谨春

    2011-01-01

    BACKGROUND: Compared with porcelain fused to metal crown, the all-ceramic crown materials have been more and more applied in clinical anterior teeth restoration due to natural and stable color, low thermal conductivity, non-electric conductivity, wear resistance, good biocompatibility, non-transparent metallic, and relatively simple operations.OBJECTIVE: To summarize the characteristics, production methods and clinical application of different all-ceramic crown materials.METHODS: A computer-based online retrieval was performed in Wanfang database and Medline database between 2001 and 2011 for articles regarding the characteristics, production methods, physical and mechanical strength, chemical and biological compatibility, aesthetic appearance and clinical application of different all-ceramic crown materials.RESULTS AND CONCLUSION: Currently, the clinically used all-ceramic materials can be divided into slip casting porcelain,casting ceramic, heat-pressed glass ceramic, glass-infiltrated ceramics, densely-sintered aluminum oxide polycrystalline, partially stabilized tetragonal zirconium oxide polycrystalline, and nano-composite ceramic. Different materials have its specific mechanical properties and clinical indications, so clinical selection must be based on specific conditions. With the advance of high-strength ceramic studies, all-ceramic restorations become widely applied, and high-aluminum ceramic represented by In-ceram and zirconia all-ceramic crowns can achieve good effects within a short and long term, foreign clinical experiments have conducted the enlargement from anterior crown to rear crown and bridge. To insure optimum long-term clinical results of all-ceramic crown restorations, the key is to overcome the fragmentation of dental prosthesis, mainly through modifying the composition, improving the anti -smash property of ceramic materials, and a series of prevention measures.%背景:相对于金属烤瓷冠而言,全瓷冠具有色泽稳定自然,导

  5. 多孔管子管板液压胀接性能影响的分析%Hydraulic Expansion Infection Analysis of Multi-hole Tube to Tubesheet Joint

    Institute of Scientific and Technical Information of China (English)

    和广庆; 杨圆明; 李翠翠

    2015-01-01

    对单孔和多孔的管子管板的液压胀接进行理论计算和有限元分析,计算结果表明,在相同和不同胀接参数下,多孔胀接后和单孔胀接的残余接触压力有明显差异;选取不同布孔的管进行拉脱力试验,试验结果表明,多孔胀接后,管子拉脱力数值与孔区布置具有相关性。模拟分析和试验结果对胀接评定试样的制作、多孔胀接性能的评价提供了参考。%The residual contact pressure of single hole and multi-hole are different for tube to tubesheet hydraulic expansion by calculation and element analysis.The result shown that tube pull out force value have relationship with tube position in multi-hole tubesheet by hydraulic expansion test.It provide a refer-ence for hydraulic expansion qualification mockup manufacture and expansion evaluation of multi-hole tubesheet joint.

  6. Introduction to Heat Medium Heat Exchanger Constructed with Double Tube and Double Tubesheet (Safe Heat Exchanger)%双管双管板热媒热交换器(安全热交换器)

    Institute of Scientific and Technical Information of China (English)

    朱敏

    2012-01-01

    双管双管板热媒热交换器是近代在双管板基础上发展起来的一种新型管壳式热交换器,也称安全热交换器,适用于管、壳程介质严禁掺混的场合.结合双管板热交换器,对双管双管板热媒热交换器的有关要点做了简要介绍,可为此类热交换器的设计、制造及使用者提供一定的参考.%Heat medium heat exchanger constructed with double tube and double tube-sheet is a new type of tubular heat exchanger developed on the basis of double tube-sheet type in recently times, it is also called safe heat exchanger. This kind of heat exchanger is able to be applied to such occasions where the fluid is strictly prohibited to blend and mix between tube side and shell side. Based on double tube-sheet heat exchanger, some key points of designing and manufacturing for heat medium heat exchanger are introduced, so it can be a reference for designer, manufacturer and uses for this kind of heat exchanger.

  7. Marginal fit of all-ceramic crowns fabricated using two extraoral CAD/CAM systems in comparison with the conventional technique

    Directory of Open Access Journals (Sweden)

    Alqahtani F

    2017-03-01

    Full Text Available Fawaz Alqahtani1,2 1Department of Prosthodontics, 2Higher Education and Scientific Research, School of Dentistry, Prince Sattam Bin Abdul-Aziz University, Al-kharj, Saudi Arabia Objective: The purpose of this study was to determine the effect of two extraoral computer-aided design (CAD and computer-aided manufacturing (CAM systems, in comparison with conventional techniques, on the marginal fit of monolithic CAD/CAM lithium disilicate ceramic crowns. Study design: This is an in vitro interventional study. Place and duration of study: The study was carried out at the Department of Prosthodontics, School of Dentistry, Prince Sattam Bin Abdul-Aziz University, Saudi Arabia, from December 2015 to April 2016. Methodology: A marginal gap of 60 lithium disilicate crowns was evaluated by scanning electron microscopy. In total, 20 pressable lithium disilicate (IPS e.max Press [Ivoclar ­Vivadent] ceramic crowns were fabricated using the conventional lost-wax technique as a control group. The experimental all-ceramic crowns were produced based on a scan stone model and milled using two extraoral CAD/CAM systems: the Cerec group was fabricated using the Cerec CAD/CAM system, and the Trios group was fabricated using Trios CAD and milled using Wieland Zenotec CAM. One-way analysis of variance (ANOVA and the Scheffe post hoc test were used for statistical comparison of the groups (α=0.05. Results: The mean (±standard deviation of the marginal gap of each group was as follows: the Control group was 91.15 (±15.35 µm, the Cerec group was 111.07 (±6.33 µm, and the Trios group was 60.17 (±11.09 µm. One-way ANOVA and the Scheffe post hoc test showed a statistically significant difference in the marginal gap between all groups. Conclusion: It can be concluded from the current study that all-ceramic crowns, fabricated using the CAD/CAM system, show a marginal accuracy that is acceptable in clinical environments. The Trios CAD group displayed the smallest

  8. 全瓷冠与金属烤瓷冠的临床应用分析%Clinical application on all ceramic crowns and metal ceramic crowns

    Institute of Scientific and Technical Information of China (English)

    代伟; 刘阳

    2015-01-01

    Objective:To investigate the aesthetic effect and the change of periodontal tissue in the restoration of all ceramic crowns and metal ceramic crowns.Methods:108 cases of dental restoration restoration on a total of 168 teeth were selected,they were divided into two groups,with 84 teeth in each group,patients in the observation group were treated with zirconia all ceramic dental restoration,while in the control with Ni Cr alloy porcelain dental restoration.Results:After 1 years,the observation group did not appear cervical margin black line,while 39 teeth in the control group had appear black or marginal discoloration problem. Conclusion:Compared with metal ceramic crowns,all ceramic crowns can reduce the damage to the periodontal tissues,and the appearance and color are excellent,with higher simulation,however,in the crown and bridge it is not as good as the metal porcelain teeth.%目的:探讨全瓷冠与金属烤瓷冠修复的美学效果及牙周组织变化.方法:收治牙齿修复患者 108 例,共计168颗牙,随机分为两组,各84颗,观察组进行二氧化锆全瓷牙修复,对照组进行镍铬合金烤瓷牙修复.结果:1年后,观察组未出现颈缘黑线情况,对照组有39颗出现颈缘发黑、变色问题.结论:全瓷冠相较于金属烤瓷冠用于牙体修复可减少对牙周组织的损伤,而且外观与色泽较为优良,有更高的仿真性,然而在冠桥折断方面不如金属烤瓷牙.

  9. Effect of In-Ceram all-ceramic crown and metal-ceramic crowns on cell viability and related gene expression in fibroblast cell lines L929

    Institute of Scientific and Technical Information of China (English)

    Lei Shi; Liang Yang; Jie-Chun Huang; En-Bao He; Zhi-Hui Wu

    2016-01-01

    Objective:To study the effect of In-Ceram all-ceramic crown and metal-ceramic crowns on cell viability and related gene expression in fibroblast cell lines L929.Methods: Fibroblast cell lines L929 were cultured and treated with extract solution of In-Ceram all-ceramic crown, Ni-Cr alloy porcelain crown and Co-Cr alloy porcelain crown respectively, and then cell viability, serum cytokine contents as well as mRNA contents of Fas, FasL, Apo-1, mTOR and P70S6k in cells were detected.Results:Cell OD values of Ni-Cr alloy group and Co-Cr alloy group were significantly lower than that of negative control group; cell OD value of In-Ceram group was significantly higher than those of Ni-Cr alloy group and Co-Cr alloy group; TNF-α, IL-6 and IL-8 contents in cell culture medium of Ni-Cr alloy group and Co-Cr alloy group were significantly higher than those of negative control group, and TNF-α, IL-6 and IL-8 contents in cell culture medium of In-Ceram group were significantly lower than those of Ni-Cr alloy group and Co-Cr alloy group and not different from those of negative control group; mRNA contents of Fas, FasL and Apo-1 in cells of Ni-Cr alloy group and Co-Cr alloy group were higher than those of negative control group, mRNA contents of mTOR and P70S6k were lower than those of negative control group, mRNA contents of Fas, FasL and Apo-1 in cells of In-Ceram group were lower than those of Ni-Cr alloy group and Co-Cr alloy group and not different from those of negative control group, and mRNA contents of mTOR and P70S6k were higher than those of Ni-Cr alloy group and Co-Cr alloy group and not different from those of negative control group.Conclusion: In-Ceram all-ceramic crown has good histocompatibility and will not affect cell viability as well as generation of inflammatory factors and expression of apoptosis and proliferation-related genes in fibroblast cell lines L929.

  10. Influence of Different Framework Designs on the Fracture Properties of Ceria-Stabilized Tetragonal Zirconia/Alumina-Based All-Ceramic Crowns

    Directory of Open Access Journals (Sweden)

    Tomofumi Sawada

    2016-05-01

    Full Text Available The aim of this study was to evaluate the fracture load and failure mode of all-ceramic crowns with different ceria-stabilized tetragonal zirconia/alumina nanocomposite (Ce-TZP/A framework designs. Four frameworks (anatomical shape: AS, with a buccal or lingual supporting structure: BS and LS, or buccal and lingual supporting structures: BLS were fabricated. All frameworks were veneered with porcelain to fabricate all-ceramic crowns followed by cementation to tooth analogs. The fracture load of each crown either without or with pre-loading (1.2 million cycles, 49 N was measured. The failure mode was classified into partial or complete fracture. Differences were tested for significance (p < 0.05 by a two-way Analysis of Variance (ANOVA, followed by Tukey’s test and by Fisher’s exact test, respectively. Without pre-loading, supporting structures did not influence the fracture load or failure mode. Partial fractures were the most common failure mode. Pre-loading promoted the severity of the failure mode, although the fracture load among the framework designs was not influenced. In the AS group, prefailures were observed during pre-loading, and complete fractures were significantly increased after pre-loading. In contrast, the failure mode of the BLS group remained unchanged, showing only partial fracture even after pre-loading. This Ce-TZP/A framework design, comprised of an anatomical shape with additional buccal and lingual structures, has the potential to reduce the chipping of the veneering porcelain.

  11. CAD/CAM Zirconia vs. slip-cast glass-infiltrated Alumina/Zirconia all-ceramic crowns: 2-year results of a randomized controlled clinical trial

    Directory of Open Access Journals (Sweden)

    Murat Cavit Çehreli

    2009-02-01

    Full Text Available The aim of this randomized controlled clinical trial was to compare the early clinical outcome of slip-cast glass-infiltrated Alumina/Zirconia and CAD/CAM Zirconia all-ceramic crowns. A total of 30 InCeram® Zirconia and Cercon® Zirconia crowns were fabricated and cemented with a glass ionomer cement in 20 patients. At baseline, 6-month, 1-year, and 2-year recall appointments, Californian Dental Association (CDA quality evaluation system was used to evaluate the prosthetic replacements, and plaque and gingival index scores were used to explore the periodontal outcome of the treatments. No clinical sign of marginal discoloration, persistent pain and secondary caries was detected in any of the restorations. All InCeram® Zirconia crowns survived during the 2-year period, although one nonvital tooth experienced root fracture coupled with the fracture of the veneering porcelain of the restoration. One Cercon® Zirconia restoration fractured and was replaced. According to the CDA criteria, marginal integrity was rated excellent for InCeram® Zirconia (73% and Cercon® Zirconia (80% restorations, respectively. Slight color mismatch rate was higher for InCeram® Zirconia restorations (66% than Cercon® Zirconia (26% restorations. Plaque and gingival index scores were mostly zero and almost constant over time. Time-dependent changes in plaque and gingival index scores within and between groups were statistically similar (p>0.05. This clinical study demonstrates that single-tooth InCeram® Zirconia and Cercon® Zirconia crowns have comparable early clinical outcome, both seem as acceptable treatment modalities, and most importantly, all-ceramic alumina crowns strengthened by 25% zirconia can sufficiently withstand functional load in the posterior zone.

  12. 不同全瓷冠边缘适合性的实验研究%The Evaluation of Different All-ceramic System in Vitro Marginal Fit

    Institute of Scientific and Technical Information of China (English)

    钱捷; 盛迅; 丁仲鹃

    2013-01-01

    Objective To evaluate the marginal fit of two all-ceramic crown systems with the metal-ceramic crown as the control group.Methods An extracted maxillofacial premolar was prepared for a full crown and 30 resin casts were subsequently duplicated.All-Ceramic crown (n =5) was fabricated on the resin casts using IPS e.max press and Cercon Y-TZP (yttriumcation-doped tetragonal zirconia polycrystals) with the metal ceramic crown as a comparison.The absolute marginal discrepancy (AMD) of the full crown was assessed by stereomicroscopy.The data were analyzed using 1-way ANOVA (α =0.05) Results The means of AMD were 58.03 ± 22.90 μm for the IPS e.max press group,90.23 ± 24.13 μm for the Cercon group and 51.68 ± 23.02 μm for the control group.There was a statistically significant difference between the Cercon group and the other two groups (P<0.01) but no significant difference was found between IPS e.max press group and the control group.Conclusion Within the limitation of this in vitro study,the marginal fit of all-ceramic crown systems is acceptable in clinical practices.The marginal fit of IPS e.max press is better than Cercon system (P<0.01),but no significant difference is found statistically between IPS e.max press group and the control group.%目的 比较IPS e.max press热压铸全瓷冠、Cercon计算机辅助设计制作的全瓷冠的边缘适合性.方法 取正畸拔除的上颌双尖牙1颗,制备全瓷冠的牙体模型,复制30个树脂代型,其中15个用于分别制作IPSe.maxpress、Cercon全瓷冠,对照组钴铬烤瓷冠(n=5),15个体视显微镜下观察、评价全冠边缘适合性,实验数据用进行单因素方差分析.结果 3组试件完全边缘缝隙的平均值(66.65±28.07).μm,IPS e.max press组(58.03±22.90) μm,Cercon组(90.23±24.13) μm,钴铬烤瓷组(51.68±23.02) μm,Cercon组的边缘缝隙最大,与其它2组差异有统计学意义(P<0.01).IPS e.max press组与钴铬烤瓷组完全边缘缝隙比

  13. 前牙全瓷冠饰瓷崩裂断口形貌分析%Fractographic analysis of clinically failed anterior all ceramic crowns

    Institute of Scientific and Technical Information of China (English)

    杜倩; 周敏波; 张新平; 赵克

    2012-01-01

    Objective To identify the site of crack initiation and propagation path of clinically failed all ceramic crowns by fractographic analysis.Methods Three clinically failed anterior IPS Empress Ⅱ crowns and two anterior In-Ceram alumina crowns were retrieved.Fracture surfaces were examined using both optical stereo and scanning electron microscopy.Fractographic theory and fracture mechanics principles were applied to disclose the damage characteristics and fracture mode.Results All the crowns failed by cohesive failure within the veneer on the labial surface.Critical crack originated at the incisal contact area and propagated gingivally. Porosity was found withiu the veneer because of slurry preparation and the sintering of veneer powder.Conclusions Cohesive failure within the veneer is the main failure mode of all ceramic crown.Veneer becomes vulnerable when flaws are present. To reduce the chances of chipping,multi-point occlusal contacts are recommended,and layering and sintering technique of veneering layer should also be improved.%目的 通过断口形貌观察分析临床失效的前牙全瓷冠,分析疲劳损伤的起源和发展,以期为优化全瓷冠桥修复体的临床设计及修复工艺提供依据.方法 收集临床失效前牙二硅酸锂基瓷冠( IPS EmpressⅡ)3例,玻璃渗透氧化铝瓷冠(In-Ceram)2例,采用体视显微镜和扫描电子显微镜观察断裂面,分析特征形貌.结果 5例全瓷冠主要失效模式均为唇侧饰瓷内聚破坏,裂纹起源于切端咬合接触区,并由切端向龈端扩展,裂纹源附近饰瓷内部见较多气孔缺陷.结论 饰瓷内聚破坏是全瓷修复失效的重要原因;饰瓷内部易出现制作缺陷,成为双层瓷修复体的薄弱环节;改良饰瓷制作及烧结工艺,设计多点咬合接触将有助于减少饰瓷崩瓷.

  14. The differentiation of materials and methods of all-ceramic restorations%全瓷修复材料和方法的分化

    Institute of Scientific and Technical Information of China (English)

    刘峰

    2011-01-01

    全瓷修复材料包括玻璃基质陶瓷、玻璃渗透氧化物陶瓷、致密氧化铝陶瓷和氧化锆陶瓷4类,全瓷修复方法包括全冠、贴面、瓷粘接修复等。不同的材料和方法搭配,获得的治疗效果差异明显。确定最适宜的搭配形式,可以明显降低临床选择治疗方案的难度。对于活髓牙修复,最佳治疗方案是采用玻璃基质陶瓷材料,进行瓷贴面或瓷粘接修复;死髓前牙一般不采用玻璃基质陶瓷全冠修复,大部分可采用的治疗方案是氧化锆陶瓷全冠修复,如果基牙变色严重可选择玻璃渗透氧化物陶瓷全冠修复;死髓后牙修复常规采用氧化锆陶瓷材料全冠修复,通过增加轴沟或钉洞辅助固位设计提高固位力,通过采用高颈环设计或者全锆冠设计提高修复体的强度。%All-ceramic materials include glass-ceramics, glass-infiltrated ceramics, pure alumina core system and zirconia core system; and all-ceramic restoration methods include crown, veneer and ceramic-bonding restorations. Different match of materials and methods will lead to different treatment result. The most suitable match can help dentists lower the risk. For most vital teeth, the most suitable design is veneers or bonded-ceramic restorations; but for unvital anterior teeth, glass-ceramic is not suitable, and in most cases zirconia crown is the best choice, or in serious strained teeth glass-infiltrated ceramic could be used; in vital posterior teeth, zirconia crown is the most suitable treatment plan, whose retention force can be increased by assistant retention form like axis grooves or pin hole, and strength can be enhanced by high cervical rings or full-zirconia design.

  15. Finite element stress analysis of all-ceramic crown of the upper central incisor in differential thickness%不同厚度上颌中切牙全瓷冠应力分布的有限元研究

    Institute of Scientific and Technical Information of China (English)

    胡建; 章非敏; 戴宁; 李泷杲; 顾卫平; 马骏驰

    2012-01-01

    Objective To investigate the stress distributions under load in an all-ceramic crown of the upper central incisor in differential thickness. Methods The 3-dimensional finite element model of all-ceramic crown of the upper central incisor in differential thickness was applied with differential loads(100, 150, 200 N). The stress values and distributions of all-ceramic crown were calculated and expressed. Results The tendency of stress distributions in all-ceramic crown of differential thickness and loads was similar. The maximal stress intensity value was located in the loading site and the cervical region. As the thickness of all-ceramic crown increased, the stress concentration reduced. When the load increased, the stress values increased, especially in the loading site and the cervical region. Conclusion The increasing of the thickness of all-ceramic crown will decrease stress concentration. Because stress concentration is mainly in cervical region and loading site, these regions should be cared in fabrication of all-ceramic crown.%目的 研究不同厚度上颌中切牙全瓷冠受载时的应力分布特点.方法 利用上颌中切牙全瓷冠的三维有限元模型,对3种不同厚度的全瓷冠分别进行100、150、200 N载荷模拟加载,并进行力学分析.结果 不同厚度全瓷冠不同载荷下的应力分布趋势相似,应力集中于冠的颈缘及加载点.随着厚度增加,应力集中趋势明显减弱.随着载荷增加,各部位的等效应力相应增加,加载点及颈缘尤为明显.结论 全瓷冠厚度的增加可降低应力集中.颈缘和加载点为应力集中区,全冠制作时应注意加强该区域.

  16. Analysis of reliability of the strength of all-ceramic crown on mandibular first molar%下颌第一磨牙全瓷冠强度可靠性的三维有限元分析

    Institute of Scientific and Technical Information of China (English)

    李岩; 张少锋; 陈建军

    2010-01-01

    目的 对随机载荷作用下全瓷冠强度的可靠性进行三维有限元分析,探讨不同加载模式对全瓷冠强度可靠性的影响.方法 建立用于下颌第一磨牙全瓷冠可靠性分析的三维有限元模型,通过概率统计方法 处理获得3~300 N区间内的随机载荷,确定3种加载模式:异常(牙合)接触加载:随机载荷分别单独加载于颊尖尖部、颊尖舌斜面和中央窝,加载面积均为0.4 mm~2;咀嚼骀接触加载:随机载荷加载位置同异常(牙合)接触加载,加载面积为1.5 mm~2;广泛(牙合)接触加载:随机载荷广泛加载于牙尖交错位时的(牙合)接触面,加载面积为12.6 mm~2.根据可靠度计算公式计算全瓷冠强度的可靠度.结果异常(牙合)接触加载时,全瓷冠颊尖尖部、颊尖舌斜面、中央窝强度的可靠度分别为97%、99%、100%;咀嚼(牙合)接触加载时,全瓷冠颊尖尖部、颊尖舌斜面、中央窝强度的可靠度分别为99%、100%、100%;广泛(牙合)接触加载时,全瓷冠骀面强度的可靠度为100%.结论 随机载荷作用下,早接触、过锐牙尖及咀嚼过硬食物造成的局部小面积集中载荷可显著降低全瓷冠强度的可靠度.%Objective To analyze the reliability of all-ceramic crown on mandibular first molar under randomized biting force,and to explore the failure possibility of all-ceramic crown.Methods Finite element(FE)models of all-ceramic crown on mandibular first molar were established using the Algor FE software.All-ceramic crown was loaded at different occlusal areas and positions with random variables of biting force,and the reliability of all-ceramic crown was analyzed.Results The occlusal contact positions were located on the fossa,inclined surface and dental cusp.When the occlusal contact area was 0.4 mm~2,The reliability of all-ceramic crown on mandibular first molar were 100%(fossa),99%(inclined surfacee),and 97%(cusp)respectively.When the occlusal contact area was 1.5 mm~2,the

  17. Effect of different ferrule designs on the fracture resistance and failure pattern of endodontically treated teeth restored with fiber posts and all-ceramic crowns

    Directory of Open Access Journals (Sweden)

    Haneef Sherfudhin

    2011-02-01

    Full Text Available OBJECTIVE: This study investigated the effect of different ferrule heights on endodontically treated premolars. MATERIAL AND METHODS: Fifty sound mandibular first premolars were endodontically treated and then restored with 7-mm fiber post (FRC Postec Plus #1 Ivoclar-Vivadent luted with self-polymerized resin cement (Multilink, Ivoclar Vivadent while the coronal section was restored with hybrid composite core build-up material (Tetric Ceram, Ivoclar-Vivadent, which received all-ceramic crown. Different ferrule heights were investigated: 1-mm circumferential ferrule without post and core (group 1 used as control, a circumferential 1-mm ferrule (group 2, non-uniform ferrule 2-mm buccally and 1-mm lingually (group 3, non-uniform ferrule 3-mm buccally and 2-mm lingually (group 4, and finally no ferrule preparation (group 5. The fracture load and failure pattern of the tested groups were investigated by applying axial load to the ceramic crowns (n=10. Data were analyzed statistically by one-way ANOVA and Tukey's post-hoc test was used for pair-wise comparisons (α=0.05. RESULTS: There were no significant differences among the failure load of all tested groups (P<0.780. The control group had the lowest fracture resistance (891.43±202.22 N and the highest catastrophic failure rate (P<0.05. Compared to the control group, the use of fiber post reduced the percentage of catastrophic failure while increasing the ferrule height did not influence the fracture resistance of the restored specimens. CONCLUSIONS: Within the limitations of this study, increasing the ferrule length did not influence the fracture resistance of endodontically treated teeth restored with glass ceramic crowns. Insertion of a fiber post could reduce the percentage of catastrophic failure of these restorations under function.

  18. In Vitro Effect of Porcelain Firing Cycle and Different Thicknesses of IPS E.max CAD Core on Marginal Accuracy of All-Ceramic Restorations

    Directory of Open Access Journals (Sweden)

    Ezatollah Jalalian

    2016-08-01

    Full Text Available Objectives: Marginal adaptation is important for long-term success of full-coverage restorations. The aim of this study was to determine the effect of porcelain firing cycle and different thicknesses of IPS e.max core on marginal accuracy of all-ceramic restorations.Materials and Methods: A standard stainless steel die with 0.8 mm classic chamfer finish line and 10° taper was used in this in vitro study. An impression was taken from the stainless steel die to fabricate 20 epoxy resin dies, which were then scanned and IPS e.max CAD cores were fabricated using computer-aided design/computer-aided manufacturing (CAD/CAM technique in two groups of 10 with  0.7 mm (group A and 0.4mm (group B core thickness. Copings were then placed on their respective dies and randomly numbered. The amount of marginal gap was measured in 10 points under a stereomicroscope (×90 magnification before and after porcelain veneering.Results: The mean gap in 0.7mm and 0.4mm core thicknesses was 15.62±2.55µm and 19.68±3.09µm before porcelain firing and 32.01±3.19µm and 35.24±3.8µm after porcelain firing. The difference in marginal gap between the two thicknesses was significant before porcelain firing but not significant after veneering. Significant differences were also found in the marginal gap before and after porcelain veneering in each group.Conclusion: The porcelain firing cycle increases marginal gap in IPS e.max CAD restorations; 0.3 mm decrease in core thickness slightly increased marginal discrepancy, however it was not significant.

  19. Effect of abutment shade, ceramic thickness, and coping type on the final shade of zirconia all-ceramic restorations: in vitro study of color masking ability

    Science.gov (United States)

    Oh, Seon-Hee

    2015-01-01

    PURPOSE The aim of the study was to evaluate the effect of abutment shade, ceramic thickness, and coping type on the final shade of zirconia all-ceramic restorations. MATERIALS AND METHODS Three different types of disk-shaped zirconia coping specimens (Lava, Cercon, Zirkonzahn: ø10 mm × 0.4 mm) were fabricated and veneered with IPS e.max Press Ceram (shade A2), for total thicknesses of 1 and 1.5 mm. A total of sixty zirconia restoration specimens were divided into six groups based on their coping types and thicknesses. The abutment specimens (ø10 mm × 7 mm) were prepared with gold alloy, base metal (nickel-chromium) alloy, and four different shades (A1, A2, A3, A4) of composite resins. The average L*, a*, b* values of the zirconia specimens on the six abutment specimens were measured with a dental colorimeter, and the statistical significance in the effects of three variables was analyzed by using repeated measures analysis of variance (α=.05).The average shade difference (ΔE) values of the zirconia specimens between the A2 composite resin abutment and other abutments were also evaluated. RESULTS The effects of zirconia specimen thickness (Pcomposite resin and gold alloy abutments was higher (close to the acceptability threshold of 5.5 ΔE) than th ose between the A2 composite resin and other abutments. CONCLUSION This in-vitro study demonstrated that abutment shade, ceramic thickness, and coping type affected the resulting shade of zirconia restorations. PMID:26576252

  20. Rotational accuracy of all-ceramic restorations on ceraone components = Liberdade rotacional de restaurações totalmente cerâmicas sobre componentes ceraone

    Directory of Open Access Journals (Sweden)

    Webster, Jacqueline

    2005-01-01

    Full Text Available Objetivo: Este estudo avaliou a desadaptação interna de sistemas cerâmicos em prótese sobre implantes em relação à liberdade rotacional das restaurações após várias cocções da porcelana. Materiais e métodos: Foram analisados três sistemas cerâmicos: Procera AllCeram, In-Ceram e CeraOne sobre análogo e intermediário CeraOne. A liberdade rotacional foi medida com um dispositivo acoplado a um relógio comparador em quatro tempos: fase de coifa, após aplicação do corpo da porcelana e glaze, e após duas queimas adicionais. Os dados foram analisados por testes de Friedman, de Kruskal-Wallis e de Wilcoxon, a = 0,01. Resultados: As médias de liberdade rotacional em graus foram: 0,08 para In-Ceram/Análogo; 1,64 para Procera/ Intermediário; 1,72 para CeraOne/Intermediário; 1,88 para CeraOne/Análogo e 1,97 para Procera/Análogo. O sistema In-Ceram sobre o análogo apresentou níveis de liberdade rotacional dez a vinte vezes menores que CeraOne e Procera. Não houve diferença entre as fases de confecção da restauração para In-Ceram. O comportamento de CeraOne e Procera foi similar, com aumento da liberdade rotacional sobre intermediário e análogo com a progressão da confecção da restauração. A liberdade rotacional sobre intermediário foi menor que sobre análogo. Conclusão: A liberdade rotacional variou em função da etapa do processo de fabricação dependendo do sistema totalmente cerâmico

  1. Research progress of zirconia all-ceramic restoration by Computer aided design and computer aided manufacture%CAD/CAM氧化锆全瓷修复的研究进展

    Institute of Scientific and Technical Information of China (English)

    商丽娟; 徐永军; 吴岩

    2014-01-01

    CAD/CAM氧化锆全瓷冠桥因其制作便捷快速、美观,稳定性和生物相容性好等优点,在口腔修复领域中有良好的应用前景。本文就CAD/CAM氧化锆全瓷修复的研究现状做一综述。%Zirconia all-ceramic crown and bridge by computer aided design ( CAD) and computer aided manufacture ( CAM) had good prospects in the field of prosthodontics, and they had the advantages of rapid and convenient production process, and good aesthetic result, stability and biocompatibility. In this review, the progress of studies and clinical applications on zirconia all-ceramic crown and bridge by CAD/CAM was introduced.

  2. Fabrication of all-ceramic dental restorations with CEREC 3D CAD/CAM system%CEREC 3D系统制作全瓷修复体的临床研究

    Institute of Scientific and Technical Information of China (English)

    赵堂民; 王莹; 夏璐; 关丽娜; 刘戈边

    2013-01-01

    Objective:To observe clinical effect of all - ceramic dental restorations fabricated by CEREC 3D CAD/CAM system. Methods: Forty - one patients with 67 all - ceramic restorations were involved in this study. After one year, the clinical performance of the restoration was evaluated by the same dentist using modified USPHS criteria. Results; 86. 57% of all -ceramic restorations scored grade A by the modified USPHS criteria. The color matching of the restoration was satisfactory in 97. 01% patients with grade A by the criteria. Conclusion: The CEREC 3D CAD/CAM system could offer easy, accurate and quick fabrication of all -ceramic dental restorations with natural color.%目的:观察椅旁CAD/CAM系统CEREC 3D制作的各类全瓷修复体的临床应用效果.方法:选取41名患者,按照CAD/CAM系统CEREC 3D标准程序制作完成各类全瓷修复体67个.修复后追踪观察1年,由同一位医师按照改良的USPHS标准对修复体进行评价.结果:86.57%的全瓷修复体各项检查标准都达到了改良的USPHS标准的A类,颜色匹配方面最令人满意,达到A类标准者为97.01%.结论:CEREC 3D CAD/CAM系统能够便捷、精准、高效地制作具有天然牙色的全瓷修复体,临床效果令人满意.

  3. Analysis of the Application of Porcelain Veneer and All Ceramic Crown O-fanterior Teeth Restoration%前牙美容修复中烤瓷贴面和全瓷冠的应用分析

    Institute of Scientific and Technical Information of China (English)

    何迎; 曲义

    2015-01-01

    Objective To analyze the effect of porcelain veneer and all ceramic crown restoration of anterior teeth in, provide the basis for clinical application. Methods 142 (352 teeth) patients in department of stomatology of our hospital from February 2008 to 2013 ,who needed for front teeth cosmetic, were divided into porcelain veneer group 66 cases (126 teeth) and all ceramic crown group of 76 cases (226 teeth) in accordance with different methods . All refractory the production technology were used in the re-pair of all ceramic crowns using. Application effect of the two groups was compared between the two groups. Results After treat-ment of patients with subjective satisfaction were 100%, of porcelain veneer patients subjective satisfaction was 90.6%, of porce-lain veneer group subjective satisfaction was 96.1%, there are no statistical differences between the two groups, P>0.05, followed up for one year, porcelain veneer group patients 9 teeth appear collapse, 5 teeth fall off, the intact rate was 88.9%, all ceramic crown group of patients with 0 teeth appear collapse, 0 teeth fall off, the intact rate was 100%, all ceramic crown group of intact rate was significantly higher than the control group, P0.05,随访一年,烤瓷贴面组患者9颗牙齿出现崩折,5颗牙齿出现脱落,完好率为88.9豫,全瓷冠组患者0颗牙齿出现崩折,0颗牙齿出现脱落,完好率为100豫,全瓷冠组完好率明显高于对照组,P<0.05。结论烤瓷贴面与全瓷冠在前牙美容修复中均有很好的美容效果,全瓷冠远期效果更加,在使用中可以根据患者的情况选择应用。

  4. Clinical effect of the CAD/CAM all-ceramic crowns on the anterior tooth restoration%计算机辅助设计和制造全瓷冠在前牙修复的临床效果

    Institute of Scientific and Technical Information of China (English)

    马慕兰; 张俭

    2013-01-01

    目的 比较计算机辅助设计和制造全瓷冠与钴铬合金烤瓷冠在前牙修复的临床效果.方法 采用计算机辅助设计和制造技术制作89件前牙二氧化锆全瓷冠,采用钴铬合金烤瓷冠制作67件前牙修复体,修复后1年复查,对边缘着色、龈缘密合度、修复体颜色、修复体周围龋、修复体折裂、牙龈健康情况进行评价.结果 在边缘着色、龈缘密合性、修复体颜色、牙龈健康状况方面差异有统计学意义(P<0.05),全瓷冠的临床效果优于钴铬合金烤瓷冠.结论 计算机辅助设计和制造全瓷冠的临床修复效果良好,是前牙修复的理想选择.%Objective To observe and compare the clinical effect of CAD/CAM all-ceramic crowns with cobalt-chromium alloy porcelain crowns in the restoration of anterior teeth.Methods Eighty-nine anterior teeth were restored with zirconia all-ceramic crowns,and 67 anterior teeth were restored with conventional cobalt-chromium alloy porcelain crowns.One year after the restoration,the marginal discoloration,change of marginal fit,color,caries around the crown,collapse porcelain and periodontal tissue heath of the two crowns were compared.Results The differences of the marginal discoloration,change of marginal fit,color,periodontal tissue heath between zirconia all-ceramic crowns and cobaltchromium alloy porcelain crowns was statistically significant (P < 0.1).The clinical effect of all-ceramic crowns was better than cobalt-chromium alloy porcelain crowns.Conclusion The clinical effect of CAD/CAM all-ceramic crowns was favourable in restoring anterior teeth.

  5. Finite element analysis of residual stress in a bilayered all-ceramic crown%饰瓷与基底瓷双层结构全瓷冠残余应力的三维有限元分析

    Institute of Scientific and Technical Information of China (English)

    马新扬; 辛海涛; 侯兵; 吴张

    2011-01-01

    目的 探讨全瓷冠高温烧结后冷却过程中,冠内不同部位以及结合界面处残余应力的分布及影响因素.方法 三维光学面扫描仪对全瓷修复体基底冠与最终牙冠表面分别进行扫描,获取冠内外点云数据;Geomagic Studio8与UG NX5将扫描后的壳体模型转成三维实体模型;运用有限元分析软件ABAQUS6.7热位移偶合单元对模型进行网格划分,施加温度载荷,模拟全瓷冠高温烧结后冷却过程,分析全瓷冠残余应力分布,并以修饰瓷与基底瓷热膨胀系数相同模型进行对比.结果 建立起饰瓷与基底瓷双层结构的全瓷冠三维有限元模型.残余应力在全瓷冠颈缘处修饰-基底瓷结合界面分布最大,在修饰瓷较厚部位残余应力分布较小.随着烧结温度的降低,残余应力逐渐增大.结论 运用三维面扫描建立的双层全瓷冠三维有限元模型精确,方法简便;全瓷冠残余应力分布较高部位与临床修复体的易破坏部位一致,提示,在进行全瓷冠修复时要注意基底瓷与修饰瓷热膨胀系数的匹配并且要保证冠边缘保持足够的瓷层厚度.%Objective To investigate the residual stress distribution of a bilayered all-ceramic crown during the cooling process using the finite element method. Methods The 3D point picture of a bilayered all-ceramic crown was obtained through three dimentional sensing system (3DSS). G eomagic Studio8 and UG NX5 were employed to transform the 3D point picture of a bilayered all-ceramic crown into a 3D solid model. The residual stress of the model was analyzed. The results were compared when the coefficient values of the veneer and core were the same. Results A 3D finite element model of bilayered dental ceramic crown was established. The maximum residual stress was found at the interface between the core and veneer on the margin of all-ceramic crown. The residual stress was minimum where the veneer ceramic was thickest. The residual stress also

  6. Clinical research of long-term aesthetic results of the anterior region of zirconia all-ceramic crown%氧化锆全瓷冠在前牙美学修复中的临床应用研究

    Institute of Scientific and Technical Information of China (English)

    王红梅; 杨永进; 蔡兴伟; 郭军; 吕晓宁

    2012-01-01

    目的:探讨氧化锆全瓷冠在前牙美学修复中的应用效果和美学效果的稳定性及其相关影响因素.方法:应用CAD/CAM技术,对20例前牙要求美学修复的患者,共44颗前牙进行氧化锆全瓷冠修复,修复后定期随访2年,通过观察患者对全瓷冠颜色的满意程度,全瓷冠颜色的口内适应情况,颜色的改变情况及牙龈组织的健康状况等,来综合评价氧化锆全瓷冠在前牙美学修复中的应用效果.结果:氧化锆的比色效果在口内的适应性较好,自然美观;两年内患者对其美学效果的评价一致,满意程度高;两年随访观察中只有2例吸烟的男性患者发生颜色改变,其余患者颜色均未发生明显改变,牙龈健康状况良好.结论:氧化锆全瓷冠的前牙美学修复效果良好且稳定,患者满意,具有广阔的应用前景.%Objective To study the repair effect, stability of aesthetic effect and its related factors of zirconia all-ceramic crowns in the anterior dental esthetics restoration. Methods 20 patients who with requirements of anterior teeth aesthetics restoration, a total of 44 anterior teeth of zirconia all-ceramic crown restoration using the CAD/CAM tecnolory, and regular follow-up of 2 years after repair. Then compare the patients' satisfactions on all-ceramic crown color, all-ceramic crown color intraoral adaptation, color changes and the gum tissue health to evaluate the application effect of zirconia all-ceramic crowns in the anterior dental esthetics repair comprehensively. Results The colorimetric effect of zirconia is natural appearance in the mouth; all the patients show high levels of satisfaction during two years follow-up observation on the aesthetic evaluation of the effect of consistent.Only two smoking male patients with color change and the remaining patients had no obvious color change.and the gingival health is good. Conclusion The repair effect of zirconia all-ceramic crown of anterior dental esthetics is

  7. 氧化锆基台在种植体支持的全瓷修复中的应用%The application of zirconia abutment in implant supported all - ceramic restoration

    Institute of Scientific and Technical Information of China (English)

    王大山; 杨建军; 邓悦; 吴品林; 杨振; 杨凤丽; 张慧敏

    2011-01-01

    目的 探讨氧化锆基台的应用及种植体支持的全瓷修复体的临床效果.方法 选择安多键内连接种植系统φ4.0×10ram种植体植入缺牙区,上颌植入6个月、下颌植入3个月后安装自制的氧化锆基台;将基台予以磨改预留修复间隙,取印模,灌制石膏模型;应用CAD/CAM制作全瓷冠、桥;将全瓷修复体与基台粘接固位;应用MINRAY口内数字X线摄片系统和X线摄片定位仪,拍摄安装氧化锆基台时和全瓷修复体粘接后36个月时的X线片进行测量,对比分析.结果 自制的氧化锆基台能与种植体顺利装配,应用该基台和CAD/CAM制作的全瓷冠、桥修复体完成的15例患者18颗种植义齿全瓷修复的即刻效果满意,追踪30-36个月,所有患者的种植义齿使用良好,修复体和基台均无松动脱落与折裂、折断,牙周无炎症及牙槽骨吸收,部分患者的牙槽骨显示增高,患者满意度高.结论 应用氧化锆基台配合CAD/CAM氧化锆全瓷冠、桥修复体,不仅可获得满意的美学效果,还有益于种植义齿周围组织的健康.%Objective ThiS study is to discuss the application of zirconia abutment and Lhe clinical results of the implant supponed all - ceramic restoration.Methods Embed the Anthogyr inter - joins implant system ( φ 4.0 × 10mm)into the edentulous region, install the self - made zirconia abutment after 6 months maxilla implantation or 3 months mandible implantation; Then the abutment is ground to reserve restoration space and the impression is made to cast plaster mould; Make the all - ceramic crown/ bridge by CAD/CAM before adhere and fix the all - ceramic restoration with the abutment; Use MINRAY digital X - ray shooting system and X - ray holders system to shoot X - ray at the time of zirconia abutment installation and 36 months after the adhesion of the all - ceramic restoration then carry out measurement and comparative analysis.Results The self - made zirconia abutment can match well

  8. Effects of Number of Firings on the Microstructure and Color Difference of Dental All-ceramic Systems%烧结次数对牙科全瓷微结构和色差的影响

    Institute of Scientific and Technical Information of China (English)

    庞莉苹; 姚江武

    2012-01-01

    Objective: To evaluate the effects of number of firings on the microstructure and color difference of dental all-ceramic systems. Methods: Specimens were made of three kinds of all- ceramics systems i. e. heat pressed all-ceramic (IPS Empress Ⅱ) . alumina all-ceramic (In-Cream alumina) and zirconia all -ceramic (Cer-con CAD/CAM zirconia). Specimens after firings were characterised using X-ray diffractQmer(XRD) and scanning electron microscope (SEM)and color difference (AE * ab) of all-ceramic after firings was measured and calculated by spectrophotometer. Results: XRD and SEM revealed the transformation of core and veneering material of Empress H from an amorphous glass to a crystalline phase and the change of alumina and zirconia in reverse after 5 firings. Significant interactions were present between the number of firings and the brand and △E * ab (P the change of color difference after 5 firings was still within perceptible and acceptable range.%目的:评价烧结次数对牙科全瓷微结构和色差的影响.方法:样本由3种品牌的全瓷材料制作,即:热压全瓷(IPS EmpressⅡ)、氧化铝全瓷(In-Cream alumina)和氧化锆全瓷(Cercon CAD/CAM zirconia).通过X射线衍射仪(x- ray diffractomer,XRD)和扫描电子显微镜(scanning electron microscope,SEM)表征烧结后全瓷样本,分光光谱仪上测量和计算烧结后全瓷样本的色差(△E* ab).结果:XRD和SEM结果显示5次烧结后热压全瓷基底冠和饰面瓷均发生由无定形玻璃相向晶相的转变,而氧化铝全瓷和氧化错全瓷的转变则相反.烧结次数与全瓷品牌和△E* ab之间存在交互作用(P<0.05).氧化铝全瓷5次烧结后的色差最大(1.9),已接近临床可接受色差的域值.结论:烧结次数因玻璃相与晶相之间的相互转变对色差造成影响,5次烧结后热压全瓷发生了玻璃相向晶相的转化,氧化锆全瓷几乎不受影响.但5次烧结后的3种全瓷的色差变化仍在视觉可接受范围内.

  9. CAD/CAM玻璃陶瓷全冠在后牙义齿修复中的运用%Clinical application of CAD/CAM all ceramic crown in the restoration of the posterior teeth

    Institute of Scientific and Technical Information of China (English)

    胡媛媛; 许琼莉; 周娟; 冷卫东; 陈永吉; 牛玉明

    2015-01-01

    Objective:To investigate the clinical use of CAD/CAM all ceramic crown in the restoration of the poste-rior teeth. Method:Thirty-five patients with forty-seven teeth of residual crown were selected and restored with CAD/CAM all ceramic crown after completely root canal therapy. Result:With 3 to 18 months following study,The retention、marginal adaptation and periodontal tissue of the dental prosthetic restoration of forty-five teeth were satisfactory ,one crowns with occlusion flaws,one crown failed for crown loose. Conclusion:The CAD/CAM all ceramic crown in the restoration for the posterior teeth can provide better effect of retention and esthetics.%目的:研究CAD/CAM全瓷冠在后牙义齿修复中的应用。方法:35例患者47个后牙经完善根管治疗后,使用CAD/CAM氧化锆全冠修复。结果:随访3~18个月,45个牙冠修复体的固位、边缘密合度、牙周状况均良好,1个冠咬合面出现隐裂,1个牙冠修复体出现松动。结论:CAD/CAM氧化锆全冠在后牙义齿修复中能够提供较好的固位及美学效果。

  10. 种植后CEREC Ⅲ全瓷单冠修复的临床研究%Clinical study of CEREC Ⅲ all ceramic crown restorations for implant

    Institute of Scientific and Technical Information of China (English)

    张建英; 赵晓华; 贾丽红; 马艳美

    2012-01-01

    目的:评价种植术后CEREC Ⅲ全瓷单冠修复1年的临床效果.方法:选取2010年1月~ 2010年6月来解放军第264医院数字口腔中心就诊采用CEREC Ⅲ全瓷单冠修复的患者22例.修复后追踪观察1年,按照改良的USPHS标准进行临床评价.结果:各项指标均达到了B标准或以上,其中颜色匹配令人满意,达到A标准者为95.45%.结论:种植后CEREC Ⅲ全瓷单冠修复具有较好的临床效果,值得推广.%Objective To evaluate the practicality and performance of CEREC III all ceramic crown restorations for implant after one year of clinical service. Methods Twenty-two patients with 22 all ceramic crown restorations were involved in the study.These crowns were made from 2010.1 ~2010.6.After one year, the clinical performance of the restorations evaluated by examiners using modified USPHS criteria. Results Crown restorations scored B using modified USPHS criteria. Most satisfactory was color match problem that achieve 95.45% of A criteria. Conclusion It was satisfactory for CEREC III all ceramic crown restorations for implant.

  11. 玻璃纤维桩与氧化锆全瓷冠修复磨牙临床分析%Clinical analysis of glass fiber piles and Zirconium all-ceramic crowns repair molar cases

    Institute of Scientific and Technical Information of China (English)

    刘红; 宋志红

    2012-01-01

    Objective To evaluate the clinical application of glass fiber post and resin core combined with zirconia all -ceramic crowns in the restoration of the molar. Methods Totally 70 teeth from 58 patients were restored by glass fiber post and resin core. All the patients were observed, examined and evaluated after 3 months to 2 years of the restoration. Results Totally 2 restoration of the residual root fell off, the failure rate is 3. 4%. One of the two was restored by glass fiber post and the other was restored by implant. Other fiber post have no fell off or broken. Zirconia all - ceramic crowns was preserved perfectly with good marginal adaption. Conclusions Molar restoration with fiber post and resin core combined with zirconia all - ceramic crowns is an ideal clinical method.%目的 探讨玻璃纤维桩树脂核联合氧化锆全瓷冠修复磨牙的临床效果.方法 玻璃纤维桩树脂核联合氧化锆全瓷冠修复磨牙58例,共70颗牙.修复完成3个月至2年,对全部病例进行随访,检查和评估.结果 2颗残根修复后纤维桩脱落,失败率为3.4%,其中1颗再次桩冠修复,一颗拔除后种植修复.其余病例氧化锆全瓷冠保持完整,边缘密合,纤维桩无脱落、折断.结论 纤维桩树脂核联合氧化锆全瓷冠修复磨牙,临床效果好,是一种较理想的修复方法.

  12. 后牙氧化锆全瓷桥的临床应用分析%Clinical analysis of All-ceramic bridges with Zirconia-base in posterior teeth repairing

    Institute of Scientific and Technical Information of China (English)

    彭利辉; 钟爱喜; 潘小波; 刘光雪; 李荣婷

    2011-01-01

    Objective To explore the effects of All-ceramic bridges with Zirconia-base in posterior teeth repairing. Methods 31 patients with 1 or 2 missing posterior teeth were restored with Zirconia-base All-ceramic bridges.and followed up 1 to 2 years. Results 30 bridges were sealed and had good retentive power.those all reached class A in marginal integrity,crown coloring,pier periodontal pocket aspects,without loosing and shedding,1 bridge was fracture and shedded,the succeed rate is 96.77. Conclusion Zirconia-base All-ceramic bridges may be used in the repairing of 1 or 2 missing posterior teeth,and the repairing effect is fine.%目的:探讨氧化锆全瓷桥在1~2颗后牙缺失固定修复中的应用.方法:选择31例单颗或2颗后牙缺失患者行氧化锆全瓷桥的固定修复、现察1~2年.结果:除1例(3单位桥)在修复1年后桥体折断并脱落,其余修复体修复效果良好,在边缘密合度、冠染色、基牙牙周袋方面均迭A级,修复体未见脱落及松动,成功率达96,77%.结论:氧化锆全瓷桥可用于1~2颗后牙缺失的3~5单位的固定桥修复,效果良好.

  13. 应用BEATIFIT口内修补全瓷牙崩瓷效果分析%Analysis of the effect of BEATIFIT applicated in intraoral repair porcelain of all ceramic dental

    Institute of Scientific and Technical Information of China (English)

    刘慧丽

    2015-01-01

    目的:探讨应用BEATIFIT口内修补全瓷牙崩瓷的应用效果。方法:收治需进行牙修复患者64例,随机分为试验组和对照组,各32例,试验组给予BEATIFIT口内修补全瓷牙崩瓷法治疗,对照组给予常规治疗。结果:试验组治疗效果显著优于对照组(P<0.05)。结论:应用BEATIFIT口内修补全瓷牙崩瓷,不仅恢复了患者原有牙的外形,同时也恢复了原有牙的色泽,临床效果显著。%Objective:To explore the effect of BEATIFIT applicated in intraoral repair porcelain of all ceramic dental.Methods:64 patients who needed dental restoration were selected.They were randomly divided into the experimental group and the control group with 32 cases in each.Patients in the experimental group were given BEATIFIT repair in all ceramic dental porcelain therapy,while patients in the control group were given routine treatment.Results:The treatment effect of the experimental group was significantly better than that of the control group(P<0.05).Conclusion:Application of BEATIFIT in intraoral repair porcelain of all ceramic dental not only can restore the original appearance of dental,but also restore the original color of the teeth,so it has a significant clinical effect.

  14. 全瓷修复技术治疗职业性牙酸蚀病的研究%The research in the treatment of occupational dental erosion using all-ceramic dental restorations

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    目的:探讨用全瓷修复技术治疗职业性牙酸蚀病的临床效果。方法:2010年3月-2013年3月来我院就诊的23例职业性牙酸蚀病患者采用全瓷修复技术治疗。分别于修复后3个月、6个月、1年、3年复查。复查内容包括:修复体边缘、解剖外形、表面光滑度、颜色、患者使用满意度。结果:整个随访期间,23例职业性牙酸蚀病患者面部外形改善,咀嚼功能恢复良好,患者对修复体的美观及舒适性均较为满意。结论:用全瓷修复技术治疗职业性牙酸蚀病能恢复患者美观,提高咀嚼效率。同时还应加强口腔健康和个人防护宣教。%Objective To evaluate the clinical outcomes of therapy using all- ceramic dental restorations for patients with occupational dental erosion. Methods From March 2010 to March 2013, twenty- three patients with occupational dental erosion were treated with all- ceramic dental restorations.The edge of the restorations, anatomical shape,smoothness,color,patients'satisfaction had been observed at 3months,6months,1 year and 3 years after treatment. Results During the follow-up period,all patients with all-ceramic dental satisfied with the appearance and masticatory function. Conclusion The all-ceramic dental restorations showed good clinical effects in improving appearance and masticatory efficiency,at the same time the oral health education and personal protection should be strengthened.

  15. Effect of different luting spaces on marginal fit of all-ceramic crowns%不同隙料厚度对全瓷冠适合性的影响

    Institute of Scientific and Technical Information of China (English)

    申丹凤; 王小林; 王璐; 吴恙; 徐凌

    2012-01-01

    目的 研究InLab MC XL系统不同隙料厚度对Cerec Blocs全瓷冠边缘和内部适合性的影响.方法 制备右上颌第一磨牙全冠预备体模型并翻制硅橡胶阴模,分别灌制全瓷石膏、超硬石膏预备体模型各30个.30个全瓷石膏预备体用于光学印模采集,获得30个数字化代型并完全随机分为6组分别设置不同隙料厚度值:0(A组)、10(B组)、20(C组)、30(D组)、40 μm(E组)和50 μm(F组),每组5个.30个超硬石膏预备体用于全瓷冠黏结,经包埋、剖开后,体式显微镜扫描试件剖面.结果 C、D组边缘适合性均介于30~ 120 μm,内部适合性均介于30 ~ 300 μm.C组与D组冠边缘适合性比较有统计学差异(P<0.05).C、D组冠内部适合性不均匀,(牙合)面适合性相对较大.结论 当隙料厚度为20、30 μm时,全瓷冠的边缘和内部适合性均在临床可接受范围内;30 μm的冠边缘适合性优于20 μm,但20、30 μm的冠(牙合)面适合性较差.%Objective To determine the effect of different luting spaces on marginal and internal fit of Cerec Blocs all-ceramic crowns in InLab MC XL system. Methods A right maxillary first molar in the standard model was prepared and subsequently replicated into silicone rubber negative mold. Respectively, 30 preparations of all-ceramic plaster and die stone were irrigated. Thirty all-ceramic plasters were used for optical impression, and then 30 three-dimensional digital images were obtained and randomly and equally divided into 6 groups, with their luting spaces were set to 0 (group A) , 10 (group B) , 20 (group C) , 30 (group D) , 40 (group E) and 50 um (group F) respectively by computer software. In addition, 30 die stones were prepared for bonding of the all-ceramic crowns. After being bonded, embedded and slitted, these specimens were scanned by stereo microscopy. Results The marginal fit was ranging from 30 to 120 um and the internal one from 30 to 300 um in groups C and D. There were

  16. The study of cyclic fatigue and lifetime for all-ceramic crown after cementation%前牙全瓷冠的循环疲劳特性及寿命分析

    Institute of Scientific and Technical Information of China (English)

    辛海涛; 郭伟国; 李玉龙

    2009-01-01

    Objective To study mechanical and cyclic fatigue behavior of IPS Empress2 under cyclic loading, and to establish guidelines for the use and design of all-ceramic crowns. Methods A 3-D finit element method model of tooth and crown were established. The strength and lifetime of all-ceramic crowns under cyclic loading in centric occlusion were investigated using computational techniques of the Abaqus and MSC Fatigue software. Results Most of the fatigue and fracture of all-ceramic crown occurred within the veneering material at cervical marginal of the crown. The number of loading cycles before failure occurred varied within specified limits 2 506 109-6 950 243. The lifetime of the crown decreased significantly as loading increased and decreased gradually as loading time increased as well. Conclusions The mechanical and fatigue behavior of ceramic materials and restorations need to be improved before clinical use in order to guarantee clinical long-term success of all-ceramic crown. The occlusal force should be adjusted properly in order to increase the longevity of all-ceramic crowns.%目的 分析全瓷冠(IPS Empres2)循环疲劳特性及寿命,为全瓷冠的临床设计、制作以及使用寿命的评估提供依据.方法 建立上中切牙及其全瓷冠的有限元模型,模拟牙尖交错(牙合)时前牙正常骀关系,在90~130 N静态载荷加载下,分析全瓷冠受力状况.根据有限元获得的应力、应变结果,使用MSC Fatigue疲劳分析软件在90~130 N循环载荷下研究全瓷冠的循环疲劳特性及寿命.结果全瓷冠唇舌侧颈部肩台为疲劳寿命最短的区域,可承受的疲劳循环次数为2 506 109~6 950 243次.前牙承担的载荷逐渐增加时,全瓷冠疲劳寿命明显降低.前牙咬合接触时间增加时,全瓷冠疲劳寿命也逐渐降低.结论全瓷冠修复对全瓷材料循环疲劳性能有较高的要求,(牙合)力对全瓷冠疲劳寿命的影响大于咬合接触时间的影响,临床应

  17. 二氧化锆全瓷冠与镍铬合金烤瓷冠临床应用比较%Comparison of clinical application of zirconia all-ceramic crowns and Ni-Cr alloy crowns

    Institute of Scientific and Technical Information of China (English)

    周俊红

    2015-01-01

    Objective To observe and compare clinical effects of the zirconia all-ceramic crowns and Ni-Cr alloy crowns. Methods 80 patients of dentistry with 106 tooth in Department of Stomatology, Zhongguancun Hospital from February 2011 to February 2012 were selected, 40 patients with 56 tooth were treated with zirconia all-ceramic crowns and were chosen as zirconia all-ceramic crowns group; 40 patients with 50 tooth were treated with Ni-Cr alloy crowns and were chosen as Ni-Cr alloy crowns group. The items of restoration retainer, restoration contour, marginal accuracy, gingival situation, secondary caries between the two groups at repairmen time and 1 year after the repairmen were compared. Results①The two groups were all reached grade A in each indicator at repairmen time. The gingival tissue of grade A in zirconia all-ceramic crowns group [96.4% (54/56)] was higher than that in Ni-Cr alloy crowns group [86.0% (43/50)] 1 year after the repairmen, the difference was statistically significant (P0.05).②The differences of plaque index in the zirconia all-ceramic crowns group and the Ni-Cr alloy crowns group between 1 year after the repairmen [(0.92±0.36), (0.89±0.40)] and before the repairmen [(0.88±0.41), (0.88±0.41)] were all not statistically significant (P> 0.05). The differences of periodontal probing depth in the zirconia all-ceramic crowns group and the Ni-Cr alloy crowns group between 1 year after the repairmen [(2.41±0.20), (2.40±0.20) mm] and before the repairmen [(2.26±0.23), (2.28±0.21) mm] were all not statistically significant (P>0.05). Con-clusion The clinical effect of Zirconia all-ceramic crowns is better than Ni-Cr alloy crowns.%目的:观察比较镍铬合金烤瓷冠和二氧化锆全瓷冠的临床应用效果。方法选取中关村医院口腔科2011年2月~2012年2月治疗的牙科患者80例106颗患牙,其中40例患者共56颗牙采用二氧化锆全瓷冠修复,设为二氧化锆全瓷冠组;40例患者50颗牙采用镍铬合

  18. Retrospective Analysis of 200 Anterior All-ceramic Crown Long-term Clinical Effects%200个前牙全瓷冠远期临床效果的回顾性分析

    Institute of Scientific and Technical Information of China (English)

    衡超; 乔梦婷

    2014-01-01

    Objective This study evaluated the long -term clinical effects of 200 feldspathic all-ceramic crown res-toration after 1 to 5 years, in order to provide clinical reference.Methods According to the United States Public Health include 8 indices, such as completeness, abrasion, color satisfaction, edge staining, marginal adaption, secondary caries, dentine hypersensitivity symptoms and gingival index (GI).We used the lifetime table to collect the statistics of the survival rate of porcelain crowns from 1 to 5 years.Results All-ceramic crowns from 1 to 5 years survival rate were 99.5%, 98.0%, 96.4%, 95.2%and 93.9%.Conclusions The long-term clinical effect of all -ceramic crowns is good.%目的:评价完成修复1~5年的200个长石质全瓷冠的远期临床效果,以期为临床效果仅为参考。方法对完成修复1~5年的200个前牙全瓷冠进行修复,参照改良美国公共健康协会( United States Public Health Society ,USPHS)评价标准对全瓷冠的修复体完整度、修复体磨耗、颜色满意度、边缘染色、边缘适合性、继发龋、牙本质敏感症状及牙龈指数(gingival index, GI)8项指标进行评估,寿命表统计烤瓷全冠1~5年存留率。结果全瓷冠1~5年存留率分别为99.5%、98.0%、96.4%、95.2%、93.9%。结论全瓷冠修复技术的远期临床效果良好。

  19. 玻璃纤维桩加全瓷冠修复前牙残根残冠的效果%Effects of glass fiber post plus all-ceramic crown on reparation of anterior teeth residual root and crown

    Institute of Scientific and Technical Information of China (English)

    郑加军; 李瑛; 彭庭莉; 谢良宪

    2012-01-01

    目的 观察玻璃纤维桩+全瓷冠修复前牙残根残冠的效果.方法 选择我科进行前牙残根、残冠修复治疗患者76例82颗患牙,采用玻璃纤维桩+全瓷冠修复,完成后6~12个月对患者进行随访,观察有无冠桩脱落、折断、松动以及牙龈、牙冠的色泽改变情况.结果 82颗患牙中,有1颗出现冠脱落,1例出现根尖叩痛.全部82颗患牙均未出现根折、桩核脱落,无继发龋坏,冠及龈边缘无变色,色泽美观.结论 玻璃纤维桩+全瓷冠修复前牙残根残冠临床效果良好.%Objective To observe the effects of glass fiber post plus all - ceramic crown on the reparation of anterior teeth residual root and crown. Methods 76 patients ( 82 front teeth ) receiving the reparation of anterior teeth residual root and crown in our department were selected and received the reparation by glass fiber post plus all - ceramic crown. Follow up was made 6-12 months after the reparation. Observe was made in whether there were any non - crown post shedding, split, and loosening and the changes in the color of gingival gum and crown. Results There were 1 tooth with the crown shedding and 1 case of percussion pain in the root among the 82 teeth. There was no split, loss of post - core, and secondary caries among all the 82 teeth. The color of their crown and gingival margin did not change. Conclusion Glass fiber post plus all - ceramic crown have good effect on the reparation of anterior teeth residual root and crown.

  20. Clinical Comparison of Zirconia All - ceramic Crown and Porcelain Fused to Metal Crown Restoration%二氧化锆全瓷冠与普通金属烤瓷冠修复的临床比较

    Institute of Scientific and Technical Information of China (English)

    张武

    2014-01-01

    目的:探讨临床使用二氧化锆全瓷冠与普通金属烤瓷冠修复的治疗效果对比。方法选择110例患者共146颗牙,随机分成两组,每组73颗牙。实验组采用二氧化锆全瓷冠进行修复;对照组采用普通金属烤瓷冠进行修复。按照美国公共健康协会制定标准评估修复情况。结果实验组全瓷冠的边缘完整性,牙龈状态,颜色等方面均表现良好,全瓷冠出现崩瓷占5.5%;对照组边缘完整性占93.15%,牙龈形态良好占95.9%,颜色表现良好占2.7%,冠出现崩瓷占8.2%。结论二氧化锆全瓷冠临床上的修复效果良好,值得临床推广使用。%Objective To comPare the theraPeutic effects of zirconia all - ceramic crown and Porcelain fused to metal crown restoration. Methods 110 Patients with a total of 146 teeth were randomly assigned into two grouPs with 73 teeth in each grouP. Zirconia all - ceramic crown restoration was used in exPerimental grouP,and Porcelain fused to metal crown restoration was used in the control grouP. Restorations were assessed according to the criteria established by United States Public Health Service(USPHS). Results Marginal integrity,gingival state and color were good in exPerimental grouP with 5. 5% fractured Porcelain. 93. 15% were good in marginal integrity,95. 9% were good in gin-gival state,2. 7% were good in color with 8. 2% fractured Porcelain in control grouP. Conclusion RePairing effects of zirconia all - ceramic crown are good,which is worth of clinical Promotion.

  1. 玻璃纤维桩和氧化锆全瓷冠在前牙美学修复中的应用%Zirconia All-ceramic Crowns And Glass Fiber Posts On Aesthetic Restoration Of Anterior Teeth

    Institute of Scientific and Technical Information of China (English)

    宋应博

    2014-01-01

    Objective:To investigate clinical effects of zirconia all-ceramic crowns and glass fiber postson on aesthetic restoration of anterior teeth. Methods:Computer Aided Design and Computer Aided Manufacture(CAD/CAM)technicals were used to make zirconia all-ceramic crowns and glass fiber posts restoration in 162 teeth in 78 patients. In the 2 years,satisfactory degree of patients was evaluated by examining oral adaptability of restoration and gingival health condition. Results:Oral adaptability was accepted by patients with high satisfactory degree. The fall of glass fiber post was found in 2 teeth and gingivitis was found in 1 tooth. The rest were all good. Conclusion:Zirconia all-ceramic crowns and glass fiber posts technical obtained wonderful effects,which was worthy of popularization in clinical practice.%目的:探讨玻璃纤维桩和氧化锆全瓷冠在前牙美学修复中的临床应用效果。方法:应用计算机辅助设计(Computer Aided Design,CAD)和计算机辅助制作(Computer Aided Manufacture,CAM)技术,对78例前牙美学修复的患者,共162颗患牙行玻璃纤维桩和氧化锆全瓷冠修复,随访2年,调查患者满意度,观察修复体在口内适应情况和牙龈的健康状况等,综合评价其应用效果。结果:玻璃纤维桩和氧化锆全瓷冠在口内的适应性良好,患者满意程度高;随访观察中有2颗玻璃纤维桩脱落,1颗牙冠边缘出现牙龈炎,其余修复体均良好。结论:玻璃纤维桩和氧化锆全瓷冠的前牙美学修复效果良好,应用前景广阔。

  2. Numerical simulation of flow and heat transfer in double tube-double tubesheet heat exchanger%双套管双管板换热器流动及传热性能数值模拟

    Institute of Scientific and Technical Information of China (English)

    周玲; 刘雪东; 李岩; 梁立军; 刘莺歌

    2011-01-01

    Heat transfer and flow behavior of double tube-double tubesheet heat exchanger were studied by CFD method. The simulation of heat transfer was performed by filling the safety chamber and the annular gap between inside and outside tubes with four different media including air, water, toluene gas and argon. The result shows that different media lead to different heat transfer results. Among which water has the best effect for heat transfer, while toluene is the worst. Backflow and around flow exist in both inlet and outlet pipe nozzles of shell side, and the fluid in tube side is well-distributed. Because of the wall boundary layer effects, the velocity is higher at the center but is lower near the wall. Different Reynolds number results in different overall heat transfer coefficients. Compared with the theoretical formula results, the simulation results are better by 15%-30%. The existing formula of overall heat transfer coefficient is not suitable for double tube-double tubesheet heat exchanger. The optimization of conventional calculation by simulating and experimental method is the focal task in the future.%采用CFD软件方法,研究双套管双管板换热器传热及流动特性.对隔绝腔连同内外套管的环形间隙内分别充入空气、水、甲苯气体和氩气4种介质进行模拟.结果表明:不同介质对传热有不同影响,充入水时的换热效果最好,甲苯气体的最差;壳程介质在流体接管进、出口附近存在回流和绕流且速度较小,管程介质流动较为均匀,受壁面边界层影响,速度在管中心处较高,在管壁处较低;采用模拟和传统计算方法分别得到不同雷诺数下的总传热系数,模拟得到的值比用常规设计计算结果好15% -30%,因此传统计算公式不能很好地解决此类换热器在实际中应用问题,通过模拟实验等手段优化传统计算方法是今后研究重点.

  3. Research on Phased Array Automatically Ultrasonic Testing Technique of Tube to Tube-sheet Welds in Heat Exchanger%换热器管板角焊缝相控阵自动超声检测技术研究

    Institute of Scientific and Technical Information of China (English)

    郭伟灿; 钱盛杰; 凌张伟

    2015-01-01

    在换热器的制作过程中,换热管与管板常采用焊接形式,焊缝的质量是保证换热器长期正常运行的关键。常规的超声检测方法具有系统复杂、检测效率低等缺点。因此,提出了相控阵超声检测技术,并开发了相控阵超声检测系统,以实现对管板角焊缝的自动超声检测。系统由周向步进电机实现周向扫查,纵向扫查采用相控阵探头电子线扫查,从而实现超声 C 扫描检测。通过带有气孔、未熔合等典型缺陷对检测系统进行试验研究。结果表明,该技术可以有效地检测出换热器管板角焊缝中的典型缺陷。%In the process of produce heat exchangers,heat exchanger′s tube and tube sheet conjunction adopt the form of welding,the quality of welding is the key insurance for the long and normal operation of the heat exchangers.The conventional ultrasonic testing method has many disadvantages like complicated system and low efficiency of detection.Thus,it puts forward the phased array ultrasonic testing technique and develops the ultrasonic testing system to accomplish the automatically ultrasonic testing of the tube to tube-sheet welds.The ultrasonic C-scan was carried out by the ultrasonic testing system with its circumfer-ential scanning by a mechanical scanning device while the axial electronic linear scanning by the phased array probe.At last,the tests on samples with typical flaws such as porosity flaws and the incomplete fu-sion flaws were performed by the ultrasonic testing system.Experiment results showed that the phased ar-ray ultrasonic technique could effectively detect the typical flaws in the tube to tube-sheet welds of heat exchanger.

  4. Clinical evaluation of IPS e.max Press all-ceramic crown and porcelain fused metal crown restorations%IPS e.max Press铸瓷与烤瓷全冠修复效果的临床观察

    Institute of Scientific and Technical Information of China (English)

    朱政; 高姗; 陈金华

    2012-01-01

    目的:评价比较IPS e.max Press铸瓷全冠、贵金属烤瓷全冠、镍铬合金烤瓷全冠的临床修复效果.方法:选择IPS e.max Press铸瓷全冠、贵金属烤瓷全冠、镍铬合金烤瓷全冠等3种材料修复上中切牙的患者各90例,参照美国公共卫生服务的相关标准对完成修复后即刻与12个月的修复体进行临床检查和相关评价,内容包括修复体颜色、牙龈边缘着色、继发龋、边缘密合度、牙龈健康状况等.结果:在修复体颜色与牙龈健康状况方面,IPS e.max Press铸瓷全冠与贵金属烤瓷全冠均显著优于镍铬合金烤瓷全冠(P<0.05);在牙龈边缘着色和边缘密合度方面,IPS e.max Press铸瓷全冠、贵金属烤瓷全冠与镍铬合金烤瓷全冠均存在显著性差异(P<0.05),IPS e.max Press铸瓷全冠最佳,贵金属烤瓷全冠次之;3组修复体均未发生继发龋.结论:IPSe.max Press铸瓷全冠修复的临床效果优良,贵金属烤瓷全冠次之,均优于镍铬合金烤瓷全冠.%Objective:To observe the clinical outcome of IPS e. max Press all-ceramic crown,gold alloy porcelain fused metal (PFM) crown and Ni-Cr alloy PFM crown restorations. Methods: Three groups of patients were treated with IPS e. max Press all-ceramic crown,gold alloy PFM crown or Ni-Cr alloy PFM crown restorations separately. The crown restorations were evaluated with the USPHS criteria for color match, marginal discoloration, secondary caries, marginal adaptation and gingival health immediately and after a period of 12 months. Results:The clinical outcome of both IPS e. max Press all-ceramic crown and gold alloy PFM crown restorations was better than Ni-Cr alloy PFM crown restorations for color match and gingival health. There was statistically significant difference in 3 groups for marginal discoloration and marginal adaptation, in which IPS e. max Press all-ceramic crown restoration was the best and gold alloy PFM crown restoration was better than Ni-Cr alloy

  5. Marginal fit of Cercon all-ceramic CAD/CAM crowns with different finish line curvature and margin%不同颈缘弯曲度和肩台形态的泽康全瓷冠的精度

    Institute of Scientific and Technical Information of China (English)

    陶建祥; 陈建荣; 依田正信

    2009-01-01

    Objective To evaluate the marginal fit of Cercon all-ceramic CAD/CAM crowns with different finish line curvature and margin in vitro.Methods Six groups of abutments (finish line curvature: 1mm, 3mm and 5mm, margin shape: chamfer and shoulder) were prepared. Thirty all-ceramic crowns were fabricated (five for each group). The marginal gaps of copings and veneered crowns were measured respectively. The data were calculated and analyzed with two-way ANOVA and Tukey HSD test (α=0.05).Results The mean marginal gaps and their standard difference (SD) of veneered crowns for 1mm, 3mm and 5mm-curvature-chamfer were 51 and 21μm, 53 and 22μm, 54 and 20μm respectively. The mean marginal gaps and their SD of veneered crowns for 1mm, 3mm and 5mm-curvature-shoulder were 49 and 18μm, 51 and 19μm, and 50 and 22μm respectively. There was no significant difference on the marginal gaps among six groups of abutments.Conclusion The marginal gaps of Cercon all-ceramic crowns were within the range of clinically acceptable values. The abutment finish line curvature and shape had no significant influence on the marginal fit of Cercon all-ceramic crowns.%目的 调查不同颈缘弯曲度和肩台形态的泽康CAD/CAM全瓷冠的边缘精度.方法 准备6种不同形态的基牙(弯曲度:1mm,3mm,5mm;肩台外形:圆弧肩台,直角肩台).制作30个泽康CAD/CAM全瓷冠(每种肩台各5个),测定陶瓷基底冠和全瓷冠的边缘缝隙.采用双因子ANOVA分析后用T检验测定有无统计学差异.结果 弯曲度1mm,3mm,5mm圆弧肩台的泽康全瓷冠的边缘缝隙分别为51(21)μm,53(22)μm,54(20)μm.弯曲度1mm,3mm,5mm直角肩台的泽康全瓷冠的边缘缝隙分别为49(18)μm,51(19)μm,50(22)μm.统计结果显示6种基牙之间没有显著性差异.结论 泽康全瓷冠有良好的边缘精度,颈缘弯曲度和肩台形态对泽康全瓷冠的边缘精度没有显著影响.

  6. Clinical application of double gingival retraction technique for all- ceramic restorations of CAD / CAM.%改良化学机械去龋技术对援非人员龋病治疗评估

    Institute of Scientific and Technical Information of China (English)

    张敬雷

    2011-01-01

    Objection: To evaluate double gingival retraction technique of all-ceramic restorations in CAD/CAM.Method: 30 patients,48 restorations in CAD/CAM were used with double gingival retraction technique, observed gingival、prepared tooth, digital impression and all-ceramic restoration. Result: The rates of satisfaction with double gingival retraction were 97.91%,95.83 % and 100 %. Conclusion:Double gingival retraction technique was an effective method in CAD/ CAM restoration.%目的:总结便携式牙科电钻结合Carisolv技术的改良化学机械去龋方法对援非工作人员龋病的防治效果.方法:援非人员35例,54个龋齿,应用便携式牙科电钻、Carisolv工具及凝胶的改良微创去龋技术去龋备洞,玻璃离子充填,对治疗效果进行半年随访.结果:改良化学去龋技术去龋充填均顺利进行,48个牙获得成功,成功率88.9%.结论:改良化学去龋技术可用于无综合治疗台的简易环境中的龋病治疗,是边远地区理想、有效、便捷的一项应急龋病治疗方法.

  7. CEREC3D制作全瓷嵌体修复后牙Ⅱ类洞临床研究%Clinical study on CEREC3D all ceramic inlay restorations for posterior tooth

    Institute of Scientific and Technical Information of China (English)

    王忠朝; 范丽苑; 兰玉燕; 王频

    2015-01-01

    目的:探讨CEREC3D CAD/CAM系统制作全瓷嵌体修复后牙Ⅱ类洞的临床效果.方法:选取28例33颗Ⅱ类洞后牙,按照CEREC3D CAD/CAM系统标准程序制作全瓷嵌体,修复1年后复诊,由同一医师按照改良USPHS标准对修复体进行评价.结果:各项标准中表面质地最令人满意,达到A标准者为90.91%,其次是颜色匹配,达到A标准者为87.88%,外形稍差,边缘适合性表现最差,有2颗患牙嵌体有破裂.结论:CEREC3D CAD/CAM系统制作全瓷嵌体修复后牙Ⅱ类洞有较好的临床效果.%Objective To approach clinical effect of all ceramic inlay restorations fabricated by CEREC3D CAD/CAM system. Methods 28 patients with 33 all inlay restorations were involved in the study.After one year,the doctor make the clinical evaluation for the restorations using modified USPHS criteria. Results Among the results,the most satisfactory criteria was external texture,90.09%inlay restorations scored A using modified USPHS criteria.Second satisfactory color match problem that achieved 87.88%of A criteria.Margin fitness was worse,2 inlays burst. Conclusion It is satisfactory for classⅡcavity ofposterior tooth that all ceramic inlay wag made by CEREC3D CAD/CAM system.

  8. 切牙单端铸瓷粘接桥的临床应用初探%Clinical application of anterior all-ceramic cantilevered resin-bonded fixed partial dentures

    Institute of Scientific and Technical Information of China (English)

    张磊; 聂宇光; 谢秋菲

    2008-01-01

    Objective To explore a fabricating method of incisor all-ceramic cantilevered resinbonded fixed partial denture(RBFPD)and evaluate their clinical performances.Methods All-ceramic cantilevered RBFPDs were made to replace 1 missing incisor in each of 10 patients.The RBFPDs with lingual surface retainer were made of Empress Ⅱ ceramic materials and luted with resin cement.The prostheses were examined at 2 weeks,1 year and 2 years after denture insertion.Examining criteria included:fracture of bridge,marginal adaptation,secondary caries,and color match.Results The average follow-up period was 14.7 months.No framework fracture and retainer debonding were observed and margihal adaptation was evaluated as good.Seven RBFPDs matched the color of adjacent teeth,and other three did not match well but within the acceptable range of tooth shade difference.Conclusions The results of this preliminary study suggest that the clinical performances of all-ceramic cantilevered RBFPDs are good in short-term evaluation,but their long-term success needs to be further investigated.%目的 探索切牙单端铸瓷粘接桥的治疗方法,观察其临床效果,以期为单端粘接桥的临床应用提供参考.方法 选择单颗切牙缺失病例10例,制作舌侧翼板固位的单端铸瓷粘接桥,共制作10件粘接桥,分别于修复后2周、1年、2年复查,复查内容包括:修复体折裂情况、边缘适合性、继发龋、颜色匹配性.结果 10例患者平均观察14.7个月.10件单端铸瓷粘接桥均无支架及饰瓷折断、裂纹,无松动;10颗基牙和固位体边缘密合,无边缘着色,无继发龋;7例修复体颜色匹配为A级,3例修复体颜色匹配为B级.结论 单端铸瓷粘接桥可修复单颗切牙缺失,牙体组织磨除量小,短期内临床效果良好,但其强度及粘接效果能否满足临床要求尚需进一步观察.

  9. Clinical evaluation of selective double gingival retraction technique for anterior all-ceramic crown prosthesis%选择性双线排龈技术在前牙全瓷冠修复中的应用研究

    Institute of Scientific and Technical Information of China (English)

    刘思言; 牟雁东

    2016-01-01

    目的:评价选择性双线排龈技术在前牙全瓷冠修复中的临床应用效果。方法选择126例门诊患者258颗前牙行全瓷冠修复,简单随机法分为两组各63例,试验组130颗基牙采用选择性双线排龈技术排龈,对照组128颗采用单线排龈技术排龈,评价牙龈止血效果满意率、预备体边缘和肩台暴露、游离龈与牙面分离满意率。结果选择性双线排龈技术的牙龈止血效果满意率、预备体边缘和肩台暴露、游离龈与牙面分离满意率分别为96.92%、96.15%及95.38%,明显高于单线排龈技术的83.59%、82.03%及81.25%。差异有统计学意义( P<0.05)。结论在前牙全瓷冠修复中,选择性双线排龈技术有很好的临床应用效果。%Objective To evaluate the clinical application effect of selective double gingival retraction technique for anterior all-ceramic crown prosthesis .Methods Two hundred and fifty-eight anterior all-ceramic crowns from 126 patients were randomly divid-ed into experimental or control groups ,63 cases in each group.Selective gingival retraction technique was used in the experimental group (130 teeth) while singlet gingival retraction technique was used in the control group (128 teeth).The effect on satisfaction rates of gingival hemostasis ,prepared teeth margins and shoulder exposure ,and satisfaction rates of separation of free gingiva and tooth sur-face were evaluated .Results The rates of satisfaction of gingival hemostasis ,prepared teeth margins and shoulder exposure and separa-tion of free gingiva and tooth surface in the selective double gingival retraction group were 96.92%,96.15%and 95.38%,respective-ly,that were significantly higher than that with singlet gingival retraction technique (83.59%,82.03%and 81.25%,respectively) (P<0.05 ) .Conclusion Selective double gingival retraction technique is an effective method for anterior all -ceramic crown prosthesis .

  10. 饰瓷对磨牙e.max双层全瓷冠断裂类型的影响%Influence of Veneering on Failure Behavior of e. max Bi- layered All- ceramic Molar Crowns. P

    Institute of Scientific and Technical Information of China (English)

    潘娱; Michael V Swain; 马骁; 张新平; 赵克

    2011-01-01

    目的:通过抗折破坏实验研究饰瓷对磨牙e.max双层全瓷冠断裂强度和断裂类型的影响,为减少临床双层全瓷修复体崩瓷提供实验依据.方法:制作单层全瓷冠(IPS e.max Press)和双层全瓷冠(IPS e.max Press/Ceram)共40个(每组20个),粘接于树脂代型后进行抗折破坏实验并记录断裂强度值;体视显微镜和扫描电子显微镜下观察断裂类型;能谱分析饰瓷-核瓷界面化学元素构成.结果:单层全瓷冠断裂强度值[(2665.4±759.2)N]与双层全瓷冠[(1431.1±404.3)N]间差异有统计学意义(P=0.000).饰瓷内部及饰瓷-核瓷界面缺陷催生裂纹造成饰瓷崩裂是双层全瓷冠断裂的主要模式.结论:饰瓷对磨牙e.max双层全瓷冠断裂强度和断裂类型均有影响;饰瓷内部及饰瓷-核瓷界面缺陷是全瓷冠断裂的主要原因,提高饰瓷断裂强度及减少界面缺陷可减少因崩瓷造成的修复体失败.%Objective: To evaluate the effect of veneering on fracture strength and failure mode of e. max bi-layered all-ceramic molar crowns, so as to provide an experimental basis for reducing veneer chipping and delamination in clinical situations. Methods: Forty all-ceramic molar crowns (IPSe. max Press) were fabricated in two groups (with and without veneering) and each group consists of twenty identical crowns. The crowns were seated on composite resin dies by adhesion and then the specimens were loaded to failure by using a universal mechanical testing machine under compressive load. Fractographic morphology and fracture mode of the failed specimens were observed by a stereomicroscope and a scanning electron microscope (SEM), and the compositions of the veneer-core interface were analyzed by energy dispersive spectroscopy (EDS). Result: Statistical analysis results indicated a significant difference of the mean fracture strength between mono-layered group (2665.4±759.2 N) and bi-layered group (1431.1±404.3 N, P=0.000). The bi-layered crowns

  11. ALL CERAMIC VENEERS: A CASE REPORT

    Directory of Open Access Journals (Sweden)

    Dileep Soni

    2016-07-01

    Full Text Available Porcelain veneers are one of the best restorative treatment options available from biological, functional, mechanical and esthetic perspectives. The use of porcelain laminate veneers to solve esthetic and/or functional problems has been shown to be a valid management option, especially in the anterior esthetic zone. The present case reports the case of attrition, anterior teeth in a healthy dentition by means of sectional porcelain veneers simply cemented onto the natural teeth and with minimal tooth preparation. In cases when patients decline orthodontic treatment, adhesively bonded porcelain veneers are a viable treatment

  12. Clinical study of zirconia all-ceramic crown and zirconia crown in molar fix prothesis%氧化锆全瓷冠与全锆冠后牙固定修复的临床研究

    Institute of Scientific and Technical Information of China (English)

    彭利辉; 钟爱喜; 潘小波; 刘光雪; 李荣婷

    2014-01-01

    目的比较氧化锆全瓷冠与全锆冠在后牙固定修复中的临床综合修复效果。方法36例后牙缺失需修复的患者,其中19例66颗牙行氧化锆全瓷冠桥修复,17例60颗牙行氧化锆全锆冠桥修复。追踪观察1~3年,由修复科医师对义齿的边缘适合性、牙龈健康情况、牙冠外形、色泽、是否崩瓷、破裂等进行评价。结果两组病例修复效果在所检查的指标中比较差异均无统计学意义( P>0.05)。结论氧化锆全瓷冠与全锆冠在边缘密合性、美观性及抗折强度方面,均能满足临床要求。但在合龈距离较短的病例中,全锆冠的修复更具优势。%Objective To compare the repairing effects between the zirconia all-ceramic crown bridge and zirconia bridge in aesthetics restoration of molars .Methods Thirty-six patients were restorated with the all-ceramic crown bridge(19 patients 66 molars) and zirconia ( bridge 17 patients 60 molars), followed up for 1 ~3 years, checked and appraised the marginal adaptation ,form,colour of the crowns ,the gingiva and crown fracture by one doc-tor.Results There was no statistically difference in the effects between the two kinds of restorations .Conclusion The two kinds of restoration can meet clinical needs in the marginal adaptation ,aesthetics and the flexural strength . The zirconia bridge is better in patients with shorter occlusogingival distance .

  13. New nano-sized Al2O3-BN coating 3Y-TZP ceramic composites for CAD/CAM-produced all-ceramic dental restorations. Part I. Fabrication of powders.

    Science.gov (United States)

    Yang, Se Fei; Yang, Li Qiang; Jin, Zhi Hao; Guo, Tian Wen; Wang, Lei; Liu, Hong Chen

    2009-06-01

    Partially sintered 3 mol % yttria-stabilized tetragonal zirconium dioxide (ZrO(2), zirconia) polycrystal (3Y-TZP) ceramics are used in dental posterior restorations with computer-aided design-computer-aided manufacturing (CAD/CAM) techniques. High strength is acquired after sintering, but shape distortion of preshaped compacts during their sintering is inevitable. The aim of this study is to fabricate new machinable ceramic composites with strong mechanical properties that are fit for all-ceramic dental restorations. Aluminum oxide (Al(2)O(3))-coated 3Y-TZP powders were first prepared by the heterogeneous precipitation method starting with 3Y-TZP, Al(NO(3))(3) . 9H(2)O, and ammonia, then amorphous boron nitride (BN) was produced and the as-received composite powders were coated via in situ reaction with boric acid and urea. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to analyze the status of Al(2)O(3)-BN on the surface of the 3Y-TZP particles. TEM micrographs show an abundance of Al(2)O(3) particles and amorphous BN appearing uniformly on the surface of the 3Y-TZP particles after the coating process. The size of the Al(2)O(3) particles is about 20 nm. The XRD pattern shows clearly the peak of amorphous BN among the peaks of ZrO(2).

  14. 心理因素对前牙全瓷修复患者美观满意度的影响%Influence of psychological factors on aesthetic satisfaction of all-ceramic restorative patients

    Institute of Scientific and Technical Information of China (English)

    袁贤君; 余穗华; 潘娱; 凌均棨; 赵克

    2012-01-01

    目的 探讨前牙全瓷修复患者心理因素及人格特征与修复后美观满意度的相关性.方法 100例前牙全瓷修复患者初诊时填写艾森克人格问卷N量表(神经质量表),计算N值总分,完成修复后进行美观满意度问卷调查,内容包括修复体美观效果、色泽效果、外形效果、面容改善及自信心是否增强等,分析心理因素与前牙全瓷修复美观满意度的相关性.结果 患者N量表得分:Nmax=23分,Nmin=3分,Navg=(9.350±5.714)分.患者对修复体的满意度均较高,美观满意度与N值相关;色泽满意度与N值和疑病症相关;外形满意度与负疚感相关;面容改善满意度与沉迷度和负疚感相关;自信心增强与否同N值、焦虑和自主性相关.结论 前牙全瓷修复患者的情绪稳定性差异较大,心理因素与前牙全瓷修复患者美观满意度有相关性.%Objective To analyze the relationship between the patients' psychological factors and esthetics satisfaction of all-ceramic restoration of anterior teeth.Methods The N scales of Eysenck personality questionnaires (EPQ) were filled at the first visit,and the total scores of N scales were calculated.After restorative treatments,the satisfaction questionnaire was used to evaluate the patients' aesthetic satisfaction on material quality,color,geometry,profile,self-confidence,etc,and to analyze the relation between psychological factors and satisfaction of the patients.Results The scores of EPQ N scale of the patients in this study were as follows:Nmax=23,Nmin =3,Navg =9.35±5.714.The patients had high satisfaction with restoration.Aesthetic satisfaction,color and self-confidence were in relation to the N scales scores,satisfaction of color was in relation to sickness suspicion,satisfaction of profile was in relation to enthrallment extent and guilty consciousness,and satisfaction of self-confidence improvement was in relation to anxiety and self-determination.Conclusions The psychologic

  15. 铸瓷固位钉对牙本质-树脂界面粘结强度的影响%Influence of all ceramic pin on the microtensile bond strength of a resin cement to dentin

    Institute of Scientific and Technical Information of China (English)

    景双林; 黄丽娟; 唐哲; 李琥; 张光东; 于金华

    2013-01-01

    目的:探讨自行研制的铸瓷固位钉对牙本质-复合树脂界面粘结强度的影响,为铸瓷固位钉进一步的临床应用提供实验依据.方法:将40颗离体牙随机分为4组:A组,铸瓷固位钉组;B组,金属自攻螺纹钉组;C组,复合树脂钉组;D组,树脂直接充填组.采用IPS e.max Press热压铸瓷系统制作铸瓷牙本质固位钉,制备标准化牙本质-固位钉-复合树脂块试件,微拉伸实验测试各组试件粘结强度,体视显微镜下观察试件断裂面形态.结果:A、B两组试件粘结强度显著高于C、D两组,差异有统计学意义(P<0.05);A组与B组、C组与D组组间粘结强度差异无统计学意义(P>0.05).A、C、D三组试件断裂模式以牙本质-树脂界面断裂为主,B组以牙本质内聚断裂为主.结论:作为一种新型牙本质固位钉,IPS e.max Press铸瓷固位钉可显著提升牙本质-复合树脂界面的粘结强度.%Objective:To evaluate the effects of self-made all ceramic pin on the micro tensile bond strength of a rensin cement to dentin.Methods:Forty extracted molars were selected and randomly divided into four groups,group A,B and C were prepared with an internal pin channel,then the all ceramic pins,self-threading retentive pins and resin composite pins were inserted into dentin respectively,group D was prepared with no internal retentive features.All subjuects were filled with composite resin.For the microtensile nontrimming technique,10 beam-shaped specimens per group were obtained.Each specimen was loaded in tension until failure and the fracture mode present were observed under stero-microscope.All the results were analyzed statistically.Results:The micro tensile bond strength of group A and B was statistically higher than that of group C and D (P < 0.05),while there were no significant difference between group A and B,or between group C and D (P > 0.05).The breakage modes were observed mainly between the dentin and adhesive interface in

  16. Inlab MC XL系统3种全瓷冠边缘和内部适合性的实验研究%Marginal and Internal Fit of Three All-ceramic Crowns in Inlab MC XL System

    Institute of Scientific and Technical Information of China (English)

    谭发兵; 王璐; 金萍; 付钢; 吴树洪

    2011-01-01

    Objective To investigate marginal and internal fit of three types of all the porcelain crowns in Inlab MC XL system and provide experimental evidences for its clinical application. Methods A lower right first molar in the standard model was prepared with 48 models also duplicated. Among them, 24 models were randomly selected to bind crowns and the other 24 models were used to bind Cerec Blocs, Incoris AL and In-ceram YZ crowns at the same numbers respectively. The fit of all-ceramic crowns were evaluated with modified United States Public Health Service(USPHS) criteria and scanning electron microscop image (SEM). Results All the marginal fit values were less than 120μm and there was statistical significance between Incoris AL and Cerec Blocs groups,Incoris AL and In-ceram YZ groups (P < 0.01).The occlucal surface's fit value (>200 μm)was the poorest in all three groups,while Cerec Blocs showed better internal fit than Incoris AL and In-ceram YZ in terms of mesial surface, lingual surface, buccal surface, and internal overall ( P < 0.05 ). However, there was no statistical significance(P > 0.05 )between Incoris AL and In-ceramYZ groups in terms of that of above observation projects. Conclusion The crowns' marginal fit of Cerec Blocs and In-ceram YZ was better than Incoris AL with the best internal fit of Cerec Blocs. Three types of all-ceramic crowns appear to have clinically acceptable marginal fit.%目的 研究Inlab MC XL系统3种瓷材料全冠的边缘和内部适合性,为临床应用提供参考.方法 制备-右下第一磨牙全冠预备体模型,复制48个代型.采用随机抽样法,24个用于采集光学印模,分别制作8个Cerec Blocs、Incoris AL、In-ceram YZ全冠,剩余24个代型用于冠的粘结.采用修正USPHS标准和SEM法评价冠的适合性.结果 修正USPHS法显示87.5%的边缘测试点临床可接受,3种瓷材料冠的边缘适合性比较无统计学意义(P>0.05);SEM法显示Incoris AL

  17. Nickel Base Alloy Cladding by Double Hot Wire TIG Welding Procedure on Tubesheet of Steam Generator%核电蒸汽发生器管板镍基合金双热丝钨极氩弧焊堆焊技术

    Institute of Scientific and Technical Information of China (English)

    罗成

    2012-01-01

    介绍了蒸汽发生器管板镍基合金堆焊新工艺——双热丝钨极氩弧焊,从热丝钨极氩弧焊的基本原理、堆焊材料的选择和堆焊工艺参数等方面作了基本论述.就双热丝钨极氩弧堆焊的使用,简述了堆焊工艺试验、工艺评定、预评定和产品应用的过程,说明镍基合金双热丝钨极氩弧焊在蒸发器管板上堆焊应用是成功的.%It is introduced that nickel - base alloy double hot wire TIG cladding procedure on tubesheet of steam generator. Those aspects are discussed basically from principle of double hot wire TIG cladding, choosing of cladding consumables and cladding parameters etc. Cladding test, procedure qualification, prequalification and product application for nickel base alloy double hot wire TIG cladding are described briefly. It is successful that application of nickel base alloy double hot wire TIG cladding procedure on tubesheet of steam generators.

  18. 全瓷牙在前牙美容修复中的应用体会%Clinical experience with the application of all-ceramic dental restoration of anterior teeth beauty

    Institute of Scientific and Technical Information of China (English)

    朱芒

    2014-01-01

    Objective Cosmetic restoration of anterior teeth in the clinical effects of the application of porcelain teeth, Summarize the clinical experience Methods Our hospital in January 2012 to June 2012 Anterior tooth of 56 patients for the study, 28 cases were randomly selected as a control group, another 28 cases as the observation group and control group patients metal alloy porcelain repair, observe group of patients with all - ceramic dental restoration, repair effect two groups were compared. Results After the restoration of the two groups of patients overall appearance, countenance improve aspects of color and shape, psychological improvement prostheses were significant differences ( <0.05); incidence of periodontitis and gingivitis patients in the observation group were significantly lower in the control group ( <0.05). Conclusion Anterior tooth application of porcelain teeth can achieve the desired aesthetic effect, and higher security, significant clinical value.%目的:探讨前牙美容修复中应用全瓷牙的临床效果。方法:选取我院收治的56例行前牙美容修复治疗的患者,从中随机抽取28例作为对照组,另28例作为观察组,对照组患者采用金属合金烤瓷修复,观察组患者则采用全瓷牙修复,并对两组患者的修复效果进行比较。结果:两组患者修复后其整体美观、面容改善、修复体色泽及外形、心理改善等方面比较,均有较大的差异(P<0.05),有统计学意义;且观察组患者的牙周炎及牙龈炎发病率均显著低于对照组(P<0.05)。结论:采用全瓷牙进行前牙美容修复可取得理想的美学效果,且安全性较高,其临床价值显著,应予广泛应用。

  19. 前牙缺损应用纤维桩联合全瓷冠修复临床效果%Tooth defect of application of fiber pile with all ceramic crown repair clinicaleffect

    Institute of Scientific and Technical Information of China (English)

    于艳

    2014-01-01

    Objective:To study the clinical application effect of the fiber pile and crown restoration of anterior teeth defect clinical analysis. Methods:From 2012 February to 2013 February in our hospital treatment of front teeth defect,90 cases with residual roots or crowns of patients(112 teeth),Give out of glass fiber post in restoration of teeth shape after the combined application of all ceramic crowns,In the 6 months after the whole treatment and 12 months for patients with tooth color change Wacom is loose,broken pile,shedding were observed and analyzed. Results:90 patients with 112 teeth with 3 crown pile shedding,occurred in 1 patients with periapical periodontitis teeth in combination therapy,All patients of 112 teeth after treatment no root,no discoloration. Conclusion:Clinical application of anterior tooth defect using the fiber pile combined with clinical crown restoration method significantly,Have favorable aesthetic effect and significant biological compatibility.%目的:研究分析前牙缺损临床采用纤维桩联合全瓷冠修复法的临床应用效果。方法:选取2012年2月至2013年2月来我院治疗的前牙缺损,残根或残冠的90例患者(112颗牙),给予进行玻璃纤维桩修复牙齿外形后联合应用全瓷冠修复,在整体治疗后的6个月及12个月对患者牙齿的色泽变化和冠桩是否出现松动、断折、脱落等情况进行观察和分析。结果:90例患者的112颗牙齿在联合治疗后有3颗冠桩脱落、1例出现牙齿跟尖周炎,全部患者112颗牙齿治疗后无断根、无变色。结论:前牙缺损临床采用纤维桩联合全瓷冠修复法的临床应用效果显著,具有良好的美学效果以及显著的生物相容特性。

  20. 饰面瓷厚度对氧化锆全瓷冠抗压缩破坏力的影响%Influence of veneering porcelain thickness on the compressive strength of zirconia all-ceramic crown

    Institute of Scientific and Technical Information of China (English)

    王晓雪; 仇亚非; 袁硕; 张钊; 郭长军

    2016-01-01

    目的:研究饰面瓷厚度对氧化锆全瓷冠抗压缩破坏力的影响。方法:常规 CAD-CAM制作氧化锆筒状基底冠25个,厚度均为0.5 mm,随机分为 A、B、C、D、E 5组,饰面瓷厚度依次为0.5、1.0、1.5、2.0、2.5 mm。万能材料试验机测试各组试件抗压缩破坏力值。采用 SPSS13.0统计软件对测试结果进行统计分析。用扫描电镜(SEM)观察试件断裂面微观结构。结果:A ~E 组试件抗压缩破坏力值依次为:(1279.96±42.85)N、(2235.44±50.14)N、(2216.38±48.97)N、(2169.22±60.40)N、(2028.70±47.37)N。A 组、E 组氧化锆全瓷修复体的抗压缩破坏力值均低于其他3组(P <0.01);其余组间抗压缩破坏力值无统计学差异(P >0.05)。扫描电子显微镜观察发现,A 组、E 组氧化锆全瓷修复体基底瓷-饰面瓷结合界面处不平坦,较为疏松;饰瓷层出现气孔及微裂纹增多、增大。结论:饰面瓷厚度低于1.0 mm 及高于2.0 mm 时,修复体的微观结构可能会受到影响,从而氧化锆全瓷冠整体抗压缩破坏力的性能受影响,建议临床应用时严格控制饰面瓷厚度。%Objective:To explore the influence of the veneering porcelain thickness on the compressive strength of zirconia all-ceramic crown.Methods:25 zirconia basement crowns with the thickness of 0.5 mm were made by CAD-CAMsystem,and then were divided into 5 groups randomly with the veneering porcelain thickness of 0.5(A),1.0(B),1.5(C),2.0(D)and 2.5 mm(E)respectively. The compressive strength of the samples was measured by a testing machine.Statistical analysis was conducted by SPSS13.0 software. The microstructure of the fractured bonding interface of the specimens was observed by scanning electron microscope(SEM).Results:The compressive strength in group A,B,C,D and E were:(1 279.96 ±42.85)N,(2 235.44 ±50.14)N,(2 216.38 ±48.97)N, (2 169.22 ±60

  1. Color differences between all-ceramic crowns and metal-ceramic crowns%氧化铝全瓷冠、镍铬合金烤瓷冠和天然牙之间色度差的比较研究

    Institute of Scientific and Technical Information of China (English)

    宋育萱; 宋欣; 毛红

    2012-01-01

    目的 明确氧化铝全瓷冠、镍铬合金烤瓷冠以及天然牙三者之间的颜色差异.方法 选择上前牙氧化铝烤瓷冠修复病例43例,用Vitapan classic比色板比色,同牙模型制作氧化铝烤瓷冠和镍铬合金烤瓷冠,用Crystaleye电脑比色仪分别读取氧化铝烤瓷冠,镍铬合金烤瓷冠和天然牙的颈,中,切三部的L*a*b*值,计算各部的色度差值.结果 氧化铝烤瓷冠与天然牙在颈,中,切部的色度差值小于2.75,肉眼无明显的感知差.镍铬合金烤瓷冠与天然牙和氧化铝烤瓷冠在颈部和中部的色度差值大于2.75,肉眼有明显的感知差,切端的色度差值小于2.75.结论 用Vitapan classic比色板比色条件下,镍铬合金烤瓷冠与天然牙切端相似,颈部和中部有明显的内眼感知差.氧化铝烤瓷冠与天然牙的色度有比较高的相似性.%Objective To evaluate the differences in color among In-ceram all ceramic crown, metal ceramic restoration, and the natural tooth. Methods Fourty-three participants with maxillary anterior all ceramic restorations were included in this study. Metal ceramic restorations were made with the same model as that used in full ceramic restorations. The color values of the In-ceram all ceramic crown, metal ceramic restoration, and the namesake tooth were measured hy using a denial spectrophotometer shade -mactching device Olympua Crystaleye. The coigr parameters (CIE1976 Lab )of cervical, body, incisal area of tooth were recorded. The ΔEa*b* between ln-teram all ceramic crown, metal ceramic restoration, and the natural tooth was calculated. Results The ΔEa*h* between In-ceram all ceramic crown and the natural tooth was Jess than 2.75.The ΔEa*b* in cervical or body area between metal ceramic restoration and the natural tooth or In-ceram all ceramic crown and metal ceramic restoration was more than 2.75. The ΔEa*h* in incisal area between metal ceramic restoration and the natural tooth or In-ceram all ceramic crown

  2. Sequence assembly

    DEFF Research Database (Denmark)

    Scheibye-Alsing, Karsten; Hoffmann, S.; Frankel, Annett Maria

    2009-01-01

    Despite the rapidly increasing number of sequenced and re-sequenced genomes, many issues regarding the computational assembly of large-scale sequencing data have remain unresolved. Computational assembly is crucial in large genome projects as well for the evolving high-throughput technologies and...... in genomic DNA, highly expressed genes and alternative transcripts in EST sequences. We summarize existing comparisons of different assemblers and provide a detailed descriptions and directions for download of assembly programs at: http://genome.ku.dk/resources/assembly/methods.html....

  3. 有限元方法模拟不同全瓷冠破坏过程初探%Analysis of the fracture processes in all-ceramic crowns by finite element analysis

    Institute of Scientific and Technical Information of China (English)

    刘亦洪; 冯海兰; 包亦望; 邱岩

    2008-01-01

    目的 用有限元方法模拟不同材料和形态的基底冠全瓷冠破坏过程,分析材料和形态对全瓷冠破坏机制的影响.方法 分别建立均匀厚度、不均匀厚度、带颈环3种基底冠形态的氧化铝和氧化锆全瓷冠模型,用BFPA'2D有限元分析软件模拟加载后全瓷冠的破坏过程.结果 6种模型均由拉应力引发破坏,裂纹始于牙尖顶的饰瓷表面,并沿基底冠与饰瓷的界面扩展.在本项研究加载条件下,仅饰瓷破坏,无基底瓷破坏,加载压强5 MPa时氧化锆模型破坏,加载6 MPa时氧化铝模型破坏.加载开始时有颈环模型呈现颈环处最小主应力集中,不均匀厚度基底冠模型呈现颈部最大主应力集中.结论 氧化锫模型的基底瓷与饰瓷界面存在更大的应力.不均匀厚度基底冠设计未增加全瓷冠破坏的风险,有颈环基底冠模型的颈部是拉应力集中的薄弱环节.%Objective To analyze the effects of core material and design on the fracture mechanism of veneered all-ceramic crowns. Methods The fracture process of 6 veneered alumina or zirconia crowns with different core design (well-distributed core, not well distributed core, and core with cervical ring) under load was analyzed by RFPA'2D finite element analysis software. Results All the six tested crowns fractured due to tension failure, and the crack started at the porcelain in the cusp and spread along the interface between core and porcelain. Under the conditions of this test, the break was only related to the porcelain and not the core, and the crack of porcelain took place earlier in zirconia crowns than in alumina crowns. Minimum stress distribution in cervical ring core design crown and maximum stress distribution in not well distributed core design crown could be seen at the neck area. Conclusions Zircania crowns presented greater stress at the interface between core and porcelain than alumina crowns. The not well distributed core design did not

  4. 桩核材料对全瓷冠半透性和颜色的影响%Influence of different posts and cores on the translucency and color of all-ceramic crown

    Institute of Scientific and Technical Information of China (English)

    李东方; 万乾炳; 杨瑛

    2011-01-01

    目的:研究不同材料桩核对全瓷冠不同部位半透性和颜色的影响.方法:制作全瓷桩核、氧化锆桩树脂核、抛光金合金桩核、抛光钯银合金桩核、钴铬合金烤瓷桩核各3 个,测量不同桩核背景下IPS-Empress2全瓷冠唇面颈1/3、中1/3和切1/3的透射率和颜色参数,计算色差(ΔE).结果:在全瓷桩核和氧化锆桩树脂核背景下,全瓷冠的颈1/3和中1/3的透射率最高;不同桩核下全瓷冠切1/3的透射率无差别.全瓷桩核背景的全瓷冠的L*值最高,抛光钯银合金桩核背景的L*值最低;在全瓷冠的颈1/3,抛光钯银合金桩核的L*、a*、b*值最低;在全瓷冠的中1/3,抛光钯银合金桩核的L*、a*值最低.结论:应用IPS-Empress 2全瓷冠修复根管治疗后的上前牙时,推荐使用全瓷桩核和氧化锆桩树脂核,可以考虑使用钴铬合金烤瓷桩核或抛光金合金桩核,不推荐使用抛光钯银合金桩核.%Objective: To study influence of different types of posts and cores on the translucency and color of all-ceramic crown.Methods: Five types of posts and cores ( Cerapost with Empress cosmo, Cerapost with composite resin, polished gold alloy, polished PaAg alloy and ceramized Co-Cr alloy)were made. Three surface zones surface( cervical, middle and incisal) of IPS-Empress 2 crowns with different posts and cores were measured for the shifts of translucency and color with a spectroradiometer (PR-650). Results: The transmittance increased obviously from cervical part to incisal part of the crowns and the transmittance of the crowns with zirconium oxide post and core was the highest. The L * values of the crowns with Cerapost and Empress cosmo were the highest while that of polished PaAg alloy were the lowest. In the cervical zone, The L * a * b * values of the crowns with polished Pa-Ag alloy post and core were the lowest. In the middle zone, the L * a * values of the crowns with polished Pa- Ag alloy post and core were the lowest

  5. 3种全瓷系统冠边缘适合性的比较%A comparison of three-dimensional marginal adaptation among three all-ceramic crown systems

    Institute of Scientific and Technical Information of China (English)

    张艳; 李江; 薛小琴; 陈振宇; 李小菊

    2011-01-01

    m and 85.1μm. CONCLUSIONS: The horizontal marginal discrepancies, vertical marginal discreparicies and absolute marginal discrepancies of the three all-ceramic crown systems were within the clinically acceptable standard. However, the IPS e.max system and the Kavo Everest System showed a better marginal fit compared with the In-Ceram alumina system. Supported by Grant from Science and Technology Projects of Changchun City(06GG163).

  6. 前牙IPS热压铸造全瓷粘接桥修复的3年临床应用研究%All-ceramic resin bonded fixed partial denture made of IPS hot-pressed casting porcelain restore anterior missing teeth: a three years clinical observation

    Institute of Scientific and Technical Information of China (English)

    周团锋; 王新知; 张桂荣

    2011-01-01

    Objective :To clinic observation of IPS Empress2 and IPS e. max all ceramic resin bonded fixed partial dentures used in one anterior teeth lost in upper jaw or less than two anterior tooth lost in lower jaw. Methods : 22 patients, 26 restorations had been made, which included 16 single-retainer all ceramic resin bonded fixed partial dentures and 10 two-retainers all ceramic resin bonded fixed partial dentures. Secondary caries of the abutments, shade in the margin of the retainers and the integrity of the restorations had been observed at 3 months, 6 months, 1 year, 2 years and 3 years after all ceramic resin bonded fixed partial dentures having been bonded. Results : In the 3 years of clinic observation of the anterior all ceramic resin bonded fixed partial dentures, 1 two-retainers restoration lost bond after it had been made for 3 months, a retainer of one two-retainers restoration was broken after 6 months, but they are still used after modified as one-retainer all ceramic resin bonded fixed partial dentures, 1 two-retainers restoration lost bond two year later, It was integrity and re-bonded again that was still stable. No secondary carries and no shade in margin of the retainers had been found. Their color matches with the nature teeth excellently. The success rate was 88.5% . Conclusion: IPS Empress 2 and IPS e. max all ceramic resin bonded fixed partial dentures should be a good selection in one or two teeth lose in anterior jaws.%目的:观察单个上前牙或下颌2个以内前牙缺失采用IPS Empress 2或IPS e.max热压铸造全瓷粘接桥的临床修复效果.方法:22位患者,共制作26件前牙热压铸造全瓷粘接桥,包括16例单翼全瓷粘接桥和10例双翼全瓷粘接桥,修复后3个月、6个月、1年,2年和3年观察修复体的完整性,基牙的继发龋,边缘着色及修复体的颜色匹配.结果:1例双翼全瓷粘接桥修复后3个月脱落;1例双翼全瓷粘接桥6个月后一侧连接体折断,均改为单翼

  7. The effects of firing numbers on the opening total pore volume, translucency parameter and color of dental all-ceramic systems%烧结次数对牙科全瓷开放性总孔体积、透明度和色度的影响

    Institute of Scientific and Technical Information of China (English)

    李水根; 庞莉苹; 姚江武

    2012-01-01

    目的 评价烧结次数对牙科全瓷开放性总孔体积(TPV)、透明度(TP)和色度的影响.方法 采用热压全瓷(IPS Empress Ⅱ)、氧化铝全瓷(In-Cream alumina blanks)和氧化锆全瓷(Cercon CAD/CAM zirconia)3种材料制作试样,使用分光光谱仪与表面积和孔隙率仪测量计算试样经过1、3、5次烧结后的TP、明度(ΔL)、彩度(ΔC)和TPV变化.应用SAS 8.0软件对数据进行统计分析.结果 相同烧结次数下,3种全瓷试件的TPV、TP、ΔL和ΔC间均存在统计学差异(P<0.05),其中TPV为热压全瓷大于氧化铝全瓷和氧化锆全瓷(P<0.05);TP和ΔL均为热压全瓷最高,氧化锆全瓷其次,氧化铝全瓷最低(P<0.05);ΔC为热压全瓷和氧化铝全瓷大于氧化锆全瓷(P<0.05).不同烧结次数下,同一全瓷试件TPV、TP、ΔL和ΔC间也存在统计学差异(P<0.05).随着烧结次数的增加,TPV逐渐减小,TP、ΔL和△C逐渐增加.烧结次数与TPV、TPV与TP和ΔL均呈负相关(P<0.05).结论 重复烧结可通过TPV变化影响全瓷修复体的TP和ΔL的稳定性.%Objective To evaluate the effects of firing numbers on the total opening pore volume (TPV), translucency parameter (TP) and color of dental all-ceramic systems. Methods Specimens of three kinds of all-ceramics systems were made, i.e. heat pressed all-ceramic (IPS Empress E), alumina all-ceramic (In-Cream alumina blanks) and zirconia all-ceramic (Cercon CAD/CAM zirconia). The specimens' TP, lightness (AL), chroma (AC) and TPY after 1, 3 and 5 firings were measured and calculated by spectrophotometer and surface area/porosity system. The data were analyzed statistically using SAS 8.0 software. Results There were significant differences in TPV, TP, AL and AC for all-ceramic specimens at same number of firings (Palumina and zirconia for TPV(Pzirconia>alumina for TP and AL(Pzirconia for AC(P<0.05). The significant differences also presented in TPV, TP, AL and AC for a same specimen at different

  8. Changes of Dental Porcelain Fused to Metal Crown, Zirconia all Ceramic Crowns on the Periodontal Tissue%试论前牙金属烤瓷冠、氧化锆全瓷冠修复后牙周组织变化

    Institute of Scientific and Technical Information of China (English)

    谷克晓; 李宁; 刘党利

    2016-01-01

    Objective Changes of dental porcelain fused to metal crown, zirconia all ceramic crowns on the periodontal tissue of the former.Methods selected in our hospital in June 2014 to 2015 December for patients with anterior teeth with PFM crowns 100 cases as the research object,divided into observation and control group. Patients in the control group were treated by the cobalt chromium alloy porcelain crowns, the observation group with zirconia all ceramic crowns, comparative analysis of the clinical therapeutic effect of the two groups.Results observation group of gingival papilla color change, gingival grey line and black line occurred rate of gingivitis was signiifcantly lower than that of the control group. Conclusion zirconia all ceramic crown restoration has a strong aesthetic,can be used to repair the anterior teeth.%目的:研究前牙金属烤瓷冠、氧化锆全瓷冠修复后牙周组织的变化。方法选取我院2014年6月~2015年12月收治的进行前牙烤瓷冠修复患者100例为研究对象,将其分为观察与对照两组,对照组进行钴铬合金烤瓷冠修复,观察组采用氧化锆全瓷冠修复,对比分析两组临床治疗效果。结果观察组的龈乳头颜色改变、牙龈缘灰线、黑线发生率牙龈炎发生率显著低于对照组。结论氧化锆全瓷冠修复具有较强的美观性,临床上可以将其用来修复前牙。

  9. Clinical therapeutic effect comparison between Sirona Cerec 3D all-ceramic crowns and porcelain fused to metal crown in anterior teeth restoration%Sirona Cerec3D全瓷冠与金属烤瓷冠修复前牙的临床对比

    Institute of Scientific and Technical Information of China (English)

    汤琼

    2012-01-01

    目的 评价Sirona Cerec 3D全瓷冠进行前牙修复的临床效果.方法 将81例(145颗前牙)患者进行随机分组,参照美国加利福尼亚牙科协会(CDA)评价标准,对使用1年的牙冠进行评价,并与同期治疗的金属烤瓷冠进行对比.结果 Sirona Cerec 3D全瓷冠修复组在边缘完整性、解剖外形、颜色和表面的成功率分别为97.5%、95%、100%、97.5%,而金属烤瓷冠对照组成功率为97.6%、92.6%、87.8%和95.1%.修复组在解剖外形和颜色方面明显优于对照组(P<0.05),且牙龈炎等副反应发生率小.结论Sirona Cerec 3D全瓷冠进行前牙修复效果良好,值得临床广泛推广.%Objective To evaluate the clinical therapeutic effect ofSirona Cerec 3D all-ceramic crowns in anterior teeth restoration.Methods 81 patients(145 anterior teeth) were divided randomly into two groups.The clinical evaluation criteria of CDA was performed 6 months to two years after wearing.And we compared the effects with porcelain fused to metal (PFM) crowns in the same period.Results On the integrity of crown margin,anatomical shape,color and surface,the succeed rate of all-ceramic crowns group were 97.5%,95%,100% and 97.5% respectively while PFM crowns group were 97.6%,92.6%,87.8% and 95.1% respectively.All-ceramic crowns group was better than PFM crowns group on the anatomical shape and color ( P < 0.05 ) and had less side effects.Conclusion Sirona Cerec 3D all-ceramic crowns has a good effect in anterior teeth restoration,worthy in expanded clinical use.

  10. Clinical evaluation of quartz fiber post and zirconia all-ceramic crowns in restoring extensively damaged molar%纤维桩联合氧化锆全冠修复磨牙大面积缺损的临床评价

    Institute of Scientific and Technical Information of China (English)

    张海燕; 彭利伟; 郭东晓

    2012-01-01

    目的:评价石英纤维桩联合氧化锆全瓷冠在磨牙大面积缺损修复活疗中的短期临床效果.方法:对28例患者32颗已完善的根管治疗的磨牙残根、残冠,采用石英纤维桩联合氧化锆全瓷冠进行修复.修复后1、6、12个月随访检查,包括修复体完整性、边缘适合性、解剖外形、颜色及牙龈.结果:修复体的完整性好(93.75%),有2例因咬过硬食物崩瓷,边缘适合性及解剖外形良好,修复体颜色与邻牙协调一致(84.37%),纤维桩核及冠均无松动、脱落,X线牙片示纤维桩与根管壁密贴,未见折裂等.结论:石英纤维桩联合氧化锆全瓷冠在磨牙大面积缺损修复治疗中可取得良好的近期临床效果.%Objective To evaluate the clinical effect of quartz fiber post and zirconia all-ceramic crowns in restoring extensively damaged molar. Methods A total of 32 molars of 28 patients were included.After complete root canal therapy,the teeth were restored with quartz fiber posts and zirconia all -ceramic crowns. Follow -up survey were conducted 1month,6 months and 12 months later,including the intactness,marginal adaptation,anatomical contour and color of prostheses and gingival health. Results 93.75% of prostheses were found to be intact;little wane was found in two all -ceramic crowns due to hard food biting.Marginal adaptation and anatomical contour was good,color of prostheses in harmony with adjacent teeth (84.37%).No loosening or exfoliation was found among quartz fiber posts and composite resin core.Roentgen diagnosis revealed posts' adaptation to root canal without fracture of posts and cores in any prostheses. Conclusion Quartz fiber posts and zirconia all-ceramic crowns are reliable and ideal materials in the restoration of extensively damaged molar.

  11. Comparison of the clinical value of porcelain veneer and all ceramic crowns in the restoration of anterior teeth%烤瓷贴面和全瓷冠在前牙美容修复中的临床应用价值比较

    Institute of Scientific and Technical Information of China (English)

    刘卫锋; 刘继华; 闫慧鑫; 王生党; 王垚

    2015-01-01

    目的:旨在比较烤瓷贴面和全瓷冠在前牙美容修复中的临床效果。方法选择2012年1月至2013年1月在我院接受烤瓷贴面和全瓷冠前牙美容修复的患者127例(320颗),根据患者的牙齿情况选择修复材料,其中接受烤瓷贴面修复患者70例(144颗),全瓷冠修复患者57例(176颗),320颗前牙均采用耐火代型技术进行修复,对所有患者随访2年。为了评价2种修复方式在前牙美容中的效果,分别在修复后3个月和24月后比较近期的美容效果和远期的完整性效果。结果经烤瓷贴面和全瓷冠修复后,患者均达到较好的近期美容效果,其主观满意度均达到100%,2种修复方式差异无统计学意义(P=0.51);全瓷冠修复的客观满意度为94.7%,高于烤瓷贴面(90.0%),表明全瓷冠的遮色效果优于烤瓷贴面。修复2年后全瓷冠的完好率仍为100%,烤瓷贴面的完好率为96.0%,二者差异有统计学意义(P=0.04),全瓷冠修复的远期完整性效果更佳。结论烤瓷贴面和全瓷冠对于前牙修复均能收到较好的美容效果,全瓷冠修复的远期完整性效果优于烤瓷贴面修复。%Objective To compare the clinical effects of porcelain veneer and all ceramic crowns in the cosmetic restoration of anterior teeth .Methods One hundred and twenty-seven patients ( 320 teeth ) , who received porcelain veneer and all ceramic crowns in the cosmetic restoration of anterior teeth from January , 2012 to January, 2013 in our hospital were chosen for our study .The repair materials for the patients′teeth were selected in accordance with the patient conditions of the teeth .All the 320 anterior teeth were repaired with refractory generation technology , of which 70 cases (144 teeth) were repaired with porcelain veneer and 57 cases (176 teeth) were repaired with all ceramic crowns , and all the patients had medical follow-ups for 2

  12. Sabot assembly

    Energy Technology Data Exchange (ETDEWEB)

    Bzorgi, Fariborz

    2016-11-08

    A sabot assembly includes a projectile and a housing dimensioned and configured for receiving the projectile. An air pressure cavity having a cavity diameter is disposed between a front end and a rear end of the housing. Air intake nozzles are in fluid communication with the air pressure cavity and each has a nozzle diameter less than the cavity diameter. In operation, air flows through the plurality of air intake nozzles and into the air pressure cavity upon firing of the projectile from a gun barrel to pressurize the air pressure cavity for assisting in separation of the housing from the projectile upon the sabot assembly exiting the gun barrel.

  13. Characteristics of U-tube assembly design for CANDU 6 type steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jun Su; Jeong, Seung Ha [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1996-06-01

    Since the first operation of nuclear steam generator early 1960s, its performance requirements have been met but the steam generator problems have been met but the steam generator problems have been major cause of reducing the operational reliability, plant safety and availability. U-tube assembly of steam generator forms the primary system pressure boundary of the plant and have experienced several types of tube degradation problems. Tube failure and leakage resulting from the degradation will cause radioactive contamination of secondary system by the primary coolant, and this may lead to unplanned plant outages and costly repair operations such as tube plugging or steam generator replacement. For the case of steam generators for heavy water reactors, e.g. Wolsong 2, 3, and 4 NPP, a high cost of heavy water will be imposed additionally. During the plant operation, steam generator tubes can potentially be subject to adverse environmental conditions which will cause damages to U-tube assembly. Types of the damage depend upon the combined effects of design factors, materials and chemical environment of steam generator, and they are the pure water stress corrosion cracking, intergranular attack, pitting, wastage, denting, fretting and fatigue, etc. In this report, a comprehensive review of major design factors of recirculating steam generators has been performed against the potential tube damages. Then the design characteristics of CANDU-type Wolsong steam generator were investigated in detail, including tube material, thermalhydraulic aspects, tube-to-tubesheet joint, tube supports, water chemistry and sludge management. 9 tabs., 18 figs., 38 refs. (Author) .new.

  14. Clinical application of the surgical crown lengthening combining all ceramic crown after failure of the anterior teeth PFM crown restoration%牙冠延长术结合全瓷冠修复在前牙烤瓷冠失败病例的应用

    Institute of Scientific and Technical Information of China (English)

    李雪峰

    2013-01-01

    目的:探讨应用牙冠延长术结合全瓷冠技术治疗前牙生物学宽度不足导致不良烤瓷冠修复的临床疗效。方法选取26例因生物学宽度不足导致的前牙修复失败病例,进行完善牙周治疗,根管治疗,并进行牙冠延长术后全瓷冠修复,观察术前,术后六周以及修复后三个月以及修复六个月的PD(探诊深度), SBI(出血指数)并予以记录。结果24例患者治疗效果较好,两例术后牙龈高度不对称,患者不甚满意。结论牙冠延长术结合全瓷冠修复可以较好的解决前牙不良烤瓷冠修复的再治疗问题。%Objective To investigate the effect after crown lengthening surgery combining all ceramic crown on anterior teeth failure of PFM crown restoration because of insufficient biological width Methods Select 26 failure cases of anterior teeth caused by insufficient biological width , repair to perfect the periodontal treatment, root canal treatment, and crown lengthening surgery. After treatment all teeth were restored by all ceramic crown, At baseline, 6 weeks after surgery and 3 months and 6 months after the restoration BOP and PD were recorded and analyzed. Results 24 patients treatment effect is good, two cases of postoperative were not very satisfied because of gum hight asymmetric. Conclusion Crown lengthening sursery combining all ceramic crown restoration can solve the failure PFM restoration on anterior teeth.

  15. 两种粘结剂粘结CAD/CAM氧化锆全瓷冠边缘微渗漏的研究%A comparative study of marginal microleakage using two kinds of cements in CAD/CAM zirconia all ceramic crown

    Institute of Scientific and Technical Information of China (English)

    梁天文; 王珏; 李英

    2012-01-01

    目的 评价两种不同粘结剂在CAD/CAM氧化锆全瓷冠修复中的边缘微渗漏情况.方法 制作10个CAD/CAM氧化锆全瓷冠,随机分成2组,分别采用磷酸锌水门汀粘结剂和Panavia F树脂粘结剂粘固于前磨牙,经温度循环试验后,将样本浸入2%品红溶液中24h,用体视显微镜观察牙-粘结剂界面边缘微渗漏状况,并进行分级评估.结果 采用SPSS 17.0软件对2组的微渗漏程度进行统计分析,得出Panavia F树脂粘结剂微渗漏小于磷酸锌水门汀粘结剂(x2=81.142,P<0.05).结论 Panavia F树脂粘结剂具有较优越的抗边缘微渗漏性能.%Objective To evaluate the marginal microleakage of CAD/CAM zirconia all ceramic crown using two different cements. Methods Ten CAD/CAM zirconia all ceramic crowns were built and randomly divided into two groups, cohered onto standard prepared human forward molars using two different cements (zinc phosphate cement and Panavia F resin cement). After temperature cycling test, all the crowns were then submerged in 2% fuchsin for 24h. The marginal microleakage at tooth cement interfaces was observed using light stereomicroscopy and evaluated in classification index. Results The marginal microleakage grade of two groups were analyzed by SPSS 17.0. The result showed that the marginal microleakage of Panavia F was less than zinc phosphate cement (x2=81.142,P<0.05). Conclusion Panavia F resin cement was suited to cement CAD/CAM zireonia all ceramic crown.

  16. Evaluation of the effect of zirconia all-ceramic fixed dental prostheses designed and manufactured by CAD/CAM in restoration of posterior teeth%CAD/CAM二氧化锆全瓷固定桥的修复效果评价

    Institute of Scientific and Technical Information of China (English)

    宓勇

    2015-01-01

    To observe the 36 months follow-up outcome of zirconia all-ceramic posterior fixed dental prostheses(FDPs)designed and manu-factured by computer aided design and computer aided manufacture (CAD /CAM)from clinical aspect,and to evaluate the success rate of zirconia framework and veneering porcelain.78 patients with less than three teeth lost which had natural opposing teeth were included.A to-tal of ninty-two zirconia all-ceramic FDPs (59 three-unit FDPs,20 four-unit FDPs and 13 five-unit FDPs)were made by CAD /CAM.Three years after cementation of the restorations,the reasons for complication and failure of FDPs in different lengths were analysed.Six FDPs were removed (frame fracture:1;porcelain fracture:1;secondary caries:2;vertical root fractures and post-core fracture after root canal therapy of premolars:2).The success rate of these FDPs was 93.5%.The success rate of zirconia all-ceramic crowns and bridges was higher.Their clinical effect was satisfactory.The main complications of these FDPs were porcelain fracture and de-bonding.%选择78名口内最多缺失2颗牙且存在对颌牙用 CAD/CAM氧化锆固定桥修复的患者,制作92件固定桥:3单位桥59件,4单位桥20件,5单位桥13件。在修复体粘接后,随访3年,分析不同长度的全瓷桥并发症的发生和失败原因的差异。6件固定桥需要拆除,修复成功率93.5%;1例因支架断裂拆除,1例由于崩瓷面积较大而拆除,2例因继发龋脱落而不能重新粘接,另外 2例前磨牙根管治疗后牙根纵裂和核折断导致修复失败。二氧化锆全瓷冠桥具有较高的成功率,临床效果满意,主要并发症是崩瓷和脱粘接。

  17. Fiber post, resin core with all-ceramic crown big dentinal body defect of the applied research%纤维桩、树脂核结合全瓷冠修复牙体大面积缺损应用研究

    Institute of Scientific and Technical Information of China (English)

    苏丽英; 方鸿满

    2012-01-01

    [目的]探讨纤维桩、树脂核结合全瓷冠修复体的临床应用及其优、劣势.[方法]161例患者的190颗残根、残冠经完善的根管治疗后,采用制作玻璃纤维桩、双固化树脂核恢复基牙外形并行氧化锫全瓷冠修复.[结果]纤维桩组95颗修复体经24个月的临床随访观察,2颗桩核折断(其中12的桩核在9个月折断,34桩核于19个月时折断),1颗桩核松动(7个月),2颗边缘可探及微小缝隙,所有修复体颜色匹配度均完好,修复效果满意,成功率为96.9%.与金属桩组比较(成功率为84.2%),差异具有统计学意义(P<0.05).[结论]玻璃纤维桩、双固化复合树脂、氧化锆全瓷冠是目前修复牙体大面积缺损的临床较理想的修复体.%[Objective] To study the fiber post and resin core combined with clinical application of all-ceramic crown restorations and their advantages and disadvantages. [Methods] In 161 patients 190 residual roots and crowns,after perfect root-pipe treatment, the production of glass fiber post, dual curing resin core recovery of abutment teeth shape parallel zirconia all-ceramic crown restoration. [Results]Fiber post 95 restorations after 24 months of clinical follow-up observation, 2 broken post and core (12, post and core in the nine month break, 34 nuclear in the 19 months to break), 1 teeth post-core loosening (7 months), 2 edge detection and tiny gap, all restorations color matching degree are in good condition, satisfactory repair, the success rate for 96.9%. And the metal pile group ( 84.2% success rate ), the difference was statistically significant ( P < 0.05 ). [ Conclusion ] Glass fiber post, dual curing composite resin, zirconia all-ceramic crown is the repair of big dentinal body defect the more ideal clinical restoration.

  18. Dump assembly

    Science.gov (United States)

    Goldmann, Louis H.

    1986-01-01

    A dump assembly having a fixed conduit and a rotatable conduit provided with overlapping plates, respectively, at their adjacent ends. The plates are formed with openings, respectively, normally offset from each other to block flow. The other end of the rotatable conduit is provided with means for securing the open end of a filled container thereto. Rotation of the rotatable conduit raises and inverts the container to empty the contents while concurrently aligning the conduit openings to permit flow of material therethrough.

  19. 全瓷冠与金属烤瓷冠在全牙义齿修复中的综合效果分析%Comparative Analysis of the Comprehensive Effect of All-ceramic Crowns and Metal Ceramic Crowns in the Application of Full Denture Prosthesis

    Institute of Scientific and Technical Information of China (English)

    李光泽

    2013-01-01

    Objective To observe the effect of all-ceramic crowns and metal ceramic crowns in the application of full denture prosthesis. Methods 86 patients who received full denture prosthesis in the Yunnan Transportation Center Hospital of Yunnan Province from January 2012 to September 2012 were chosen as the research object. According to the order of patients admission tag,patients with the odd tag were as the control group,patients with the even were as the observation group, and 43 patients in each group. Patients in the control group received metal ceramic crown repair, and patients in the observation group received all-ceramic crown repair. Patients in the two groups were followed up for 12 months to 24 months, and the black line on the gingival cervical margin, periodontal damage and porcelain crowns crack were compared between the two groups. Results The cervical margin black line ratios in the observation group and the control group were 2.33%(1/43) and 18.60% (8/43), the difference was statistically significant ( <0.05) . 11.63% (5/43) of patients in the observation group appeared cracks and fracture, compared with the control group of 2.33% (1/43), there was a statistically significant difference ( <0.05) . Conclusion Compared with etal ceramic crowns, all-ceramic crowns in full denture prosthesis have less injury in periodontal tissue and weaker anti-crack intensity, so the clinicians should choose the all-ceramic crowns based on the patients' indications.%目的:观察全瓷冠与金属烤瓷冠在全牙义齿修复中的应用效果.方法选择云南省交通中心医院2012年1月至2012年9月的86例进行全牙义齿修复的患者作为研究对象,按照患者入院的先后顺序标记,奇数作为对照组,偶数作为观察组,每组43例.对照组采用金属烤瓷冠,观察组采用全瓷冠进行修复,随访12个月~24个月比较2组牙龈颈缘黑线情况、牙周损害情况及牙冠裂瓷.结果观察组与对照组

  20. Observation on clinical application value of all-ceramic crown of glass ifber post and resin core for residual crown and residual root repair of anterior teeth%玻璃纤维桩树脂核全瓷冠在前牙残冠及残根修复中的临床应用价值探讨

    Institute of Scientific and Technical Information of China (English)

    李伟; 赵国廷; 徐革英

    2014-01-01

    Objective To observe the clinical application value and effect of all-ceramic crown of glass fiber post and resin core for residual crown and residual root repair of anterior teeth. Method 106 cases with residual crown and residual root of anterior teeth treated in our hospital from April 2010 to March 2012 were selected, and the patients received repair after root canal therapy. The patients were divided into two groups according to repair modes, observation group and control group. Observation group received repair of all-ceramic crown of glass ifber post and resin core, and control group received repair of cast metal post-core and baked porcelain crown. The repair effect of two groups was compared and observed. Result After following up for two years, the success rate and satisfactory degree of observation group was evidently higher than that of control group, and the expulsion rate and odontagma rate of restoration was lower than that of control group (P<0.05), which had statical signiifcance. Conclusion Applying all-ceramic crown of glass ifber post and resin core to all-ceramic crown of glass ifber post and resin core for residual crown and residual root repair of anterior teeth not only has good retention, good color and appearance maintenance, and has little stimulation on the surrounding tissues, but also can effectively reduce detachment and fracture of restoration, which evidently improves the success rate of repair and satisfactory degree of patients, which has ideal clinical application value.%目的:探讨在前牙残冠、残根修复中使用玻璃纤维桩树脂核与全瓷冠的临床应用效果及价值。方法选取本院2010年4月至2012年3月收治的前牙残冠、残根患者106例,根管治疗后修复,并根据修复方式分为观察组与对照组,观察组患者使用玻璃纤维桩树脂核与全瓷冠修复,对照组患者使用铸造金属桩核与烤瓷冠或全瓷冠修复,对比观察两

  1. CAD/CAM全瓷嵌体与复合树脂嵌体修复后牙II类洞临床疗效对比分析%Comparison of clinical efficacy of CAD/CAM all-ceramic inlay and composite resin inlay in restoration of posterior ClassⅡcavity

    Institute of Scientific and Technical Information of China (English)

    董丽平; 孙璐; 杨洋; 陈丽娜; 尚丹丹

    2014-01-01

    Objective:To compare the clinical efficacy of CAD/CAM all-ceramic inlay and composite resin inlay in restoring ClassⅡcavity of posterior teeth. Methods:226 posterior teeth of ClassⅡcavity from 193 patients were recruited in our clinical trial. 101 teeth of the selected teeth were restored with CAD/CAM all-ceramic inlays, and the rest was restored by composite resin inlays. Prosthesis abrasion, prosthesis fracture, prosthesis off, marginal adapta-tion, edge coloring, and secondary caries of the two groups were evaluated during 6-month, 12-month and 18-month follow-up appointments, respectively. Results: There were significant differences in prosthesis abrasion and edge coloring between the two groups (P0.05). The success rate of CAD/CAM all-ceramic inlay is 96.84%, and the composite resin inlay is 81.05%. There was significant difference between the success rates (P<0.05). Conclusion:The efficacy of CAD/CAM all-ceramic inlay is better than that of composite resin inlay during the treatment of the posterior ClassⅡcavities.%目的:对比分析CAD/CAM全瓷嵌体与复合树脂嵌体修复后牙Ⅱ类洞的临床疗效。方法:选择在解放军总医院口腔内科就诊的后牙Ⅱ类洞患者193例(共226颗牙),根据患者意愿,其中101颗采用CAD/CAM全瓷嵌体修复,其余125颗采用复合树脂嵌体修复,分别在术后6个月、12个月、18个月进行随访,观察其修复体磨耗、折裂、脱落、边缘密合性、边缘着色及继发龋等情况。结果:2种嵌体在修复体磨耗及边缘着色的差异有统计学意义(P<0.05),在修复体折裂、修复体脱落、继发龋和边缘密合性的差异无统计学意义(P>0.05)。 CAD/CAM 全瓷嵌体的成功率为:96.84%,树脂嵌体的成功率为:81.05%,两组之间成功率的差异有统计学意义(P<0.05)。结论:在后牙Ⅱ类洞缺损的修复治疗中, CAD/CAM全瓷嵌体的效果优于复合树脂嵌体。

  2. General Assembly

    CERN Multimedia

    Staff Association

    2016-01-01

    5th April, 2016 – Ordinary General Assembly of the Staff Association! In the first semester of each year, the Staff Association (SA) invites its members to attend and participate in the Ordinary General Assembly (OGA). This year the OGA will be held on Tuesday, April 5th 2016 from 11:00 to 12:00 in BE Auditorium, Meyrin (6-2-024). During the Ordinary General Assembly, the activity and financial reports of the SA are presented and submitted for approval to the members. This is the occasion to get a global view on the activities of the SA, its financial management, and an opportunity to express one’s opinion, including taking part in the votes. Other points are listed on the agenda, as proposed by the Staff Council. Who can vote? Only “ordinary” members (MPE) of the SA can vote. Associated members (MPA) of the SA and/or affiliated pensioners have a right to vote on those topics that are of direct interest to them. Who can give his/her opinion? The Ordinary General Asse...

  3. Assembling consumption

    DEFF Research Database (Denmark)

    Assembling Consumption marks a definitive step in the institutionalisation of qualitative business research. By gathering leading scholars and educators who study markets, marketing and consumption through the lenses of philosophy, sociology and anthropology, this book clarifies and applies...... the investigative tools offered by assemblage theory, actor-network theory and non-representational theory. Clear theoretical explanation and methodological innovation, alongside empirical applications of these emerging frameworks will offer readers new and refreshing perspectives on consumer culture and market...... societies. This is an essential reading for both seasoned scholars and advanced students of markets, economies and social forms of consumption....

  4. General Assembly

    CERN Multimedia

    Staff Association

    2015-01-01

    Mardi 5 mai à 11 h 00 Salle 13-2-005 Conformément aux statuts de l’Association du personnel, une Assemblée générale ordinaire est organisée une fois par année (article IV.2.1). Projet d’ordre du jour : 1- Adoption de l’ordre du jour. 2- Approbation du procès-verbal de l’Assemblée générale ordinaire du 22 mai 2014. 3- Présentation et approbation du rapport d’activités 2014. 4- Présentation et approbation du rapport financier 2014. 5- Présentation et approbation du rapport des vérificateurs aux comptes pour 2014. 6- Programme 2015. 7- Présentation et approbation du projet de budget 2015 et taux de cotisation pour 2015. 8- Pas de modifications aux Statuts de l'Association du personnel proposée. 9- Élections des membres de la Commission é...

  5. General Assembly

    CERN Multimedia

    Staff Association

    2016-01-01

    Mardi 5 avril à 11 h 00 BE Auditorium Meyrin (6-2-024) Conformément aux statuts de l’Association du personnel, une Assemblée générale ordinaire est organisée une fois par année (article IV.2.1). Projet d’ordre du jour : Adoption de l’ordre du jour. Approbation du procès-verbal de l’Assemblée générale ordinaire du 5 mai 2015. Présentation et approbation du rapport d’activités 2015. Présentation et approbation du rapport financier 2015. Présentation et approbation du rapport des vérificateurs aux comptes pour 2015. Programme de travail 2016. Présentation et approbation du projet de budget 2016 Approbation du taux de cotisation pour 2017. Modifications aux Statuts de l'Association du personnel proposée. Élections des membres de la Commissio...

  6. General assembly

    CERN Multimedia

    Staff Association

    2015-01-01

    Mardi 5 mai à 11 h 00 Salle 13-2-005 Conformément aux statuts de l’Association du personnel, une Assemblée générale ordinaire est organisée une fois par année (article IV.2.1). Projet d’ordre du jour : Adoption de l’ordre du jour. Approbation du procès-verbal de l’Assemblée générale ordinaire du 22 mai 2014. Présentation et approbation du rapport d’activités 2014. Présentation et approbation du rapport financier 2014. Présentation et approbation du rapport des vérificateurs aux comptes pour 2014. Programme 2015. Présentation et approbation du projet de budget 2015 et taux de cotisation pour 2015. Pas de modifications aux Statuts de l'Association du personnel proposée. Élections des membres de la Commission électorale. &am...

  7. 舌侧错位侧切牙行氧化锆全瓷修复远期疗效和美学效果研究%A study of long-term curative and aesthetic effects in restoring lateral incisor lingual dislocation lines by zirconia all-ceramics

    Institute of Scientific and Technical Information of China (English)

    曹雪春; 侯丽萍

    2015-01-01

    目的:评价舌侧错位侧切牙行氧化锆全瓷修复远期疗效和美学效果。方法选取2012年4月—2014年5月在我院口腔科就诊的106例(130颗)侧切牙舌侧错位患者,随机分为试验组和对照组,试验组53例(68颗)采取氧化锆全瓷修复,对照组53例(62颗)采取镍铬合金烤瓷修复,随访2年,对两组患者修复体效果进行评价,对两组患者对修复美观效果满意度情况进行调查。结果随访2年时,试验组患者修复体外形、颜色匹配、牙龈适应性和牙敏感性合格率分别为97.1%、100.0%、94.1%和94.1%,均高于对照组患者,差异均具有统计学意义(P<0.05);试验组患者对修复体美观效果满意度为98.1%,显著高于对照组的81.1%,差异具有统计学意义(P<0.05)。结论氧化锆全瓷应用于侧切牙舌侧错位修复可以有效改善患者远期疗效和美观效果,提高患者对美观效果满意度。%Objective To evaluate the long-term curative and aesthetic effects of zirconia all-ceramic restorations in lateral incisor lingual dislocation lines .Methods In our department of stomatology from April ,2012 to May,2014,130 teeth with lateral incisor lin-gual errors from 106 patients were selected and randomly divided into the experimental group and the control group .In the experimental group,53 patients (68 teeth)took zirconia all-ceramic restorations;in the control group,53 cases (62 teeth)took nickel-chromium alloy porcelain restorations .During a 2-year-follow-up,the restoration effects of both groups were evaluated ,and their aesthetic satisfaction to-wards the restorations was investigated .Results After 2 years,the qualified rate of the prosthesis shape ,color matching,gingival a-daptability and tooth sensitivity in the experiment group were 97.1%,100.0%,94.1%,and 94.1%,respectively,all of which were higher than that of the control group ,and the differences were

  8. Clinical retrospective analysis of all-ceramic single crown in terms of fracture resistance with CAD/CAM zirconia-base:a four-year follow-up%CAD/CAM氧化锆全瓷单冠抗折裂随访4年临床分析

    Institute of Scientific and Technical Information of China (English)

    郑茜聪; 蔡志斌

    2015-01-01

    Objective To evaluate the fracture resistance of CAD / CAM zirconia all-ceramic crowns. Methods 284 all-ceramic crowns were fabricated for 189 patients. 226 restorations of 156 patients were clinically followed up for 2. 5-5. 5 years. The site of crown, fracture or breakage,loose or dislodgement were observed. Results The fracture rate was 0. 9% at 1 year after the insertion date, 2. 1% after two years,3. 3% after three years,7. 1% after four years. Overall the fracture rate was 9. 7% with 226 restorations. Base crown fracture took place in two cases. A statistically significant difference was found for fractures when the opposing dentition of natural teeth and fixed restorations were compared (P = 0. 034). The fractures were most commonly noted when the opposing dentition was a fixed metal ceramic or other ceramic restorations. Conclusions The fracture resistance of CAD / CAM zirconia all-ceramic crowns was acceptable clinically and it can be a preferred esthetic restoration.%目的:回顾分析评价CAD / CAM 氧化锆全瓷单冠抗折裂性能。方法为189例患者制作CAD / CAM 氧化锆全瓷冠284颗,随访到156例患者的226颗全瓷冠,随访2.5~5.5年,对修复体的位置、崩瓷、基底冠折断、修复体松动脱落等情况进行观察。结果 CAD / CAM 全瓷冠1年的折裂率0.9%,2年的折裂率为2.1%,3年的折裂率为3.3%,4年的折裂率为7.1%,观察期间全瓷冠的总折裂率为9.7%。其中2例患者发生基底冠折裂。当对颌分别为天然牙或瓷修复体时,全瓷冠的折裂率有显著性差异( P =0.034)。全瓷冠的折裂后牙明显高于前牙区(P <0.01)。结论 CAD / CAM 氧化锆全瓷冠整体抗折裂性能临床可接受,可作为临床首选的美学修复体。

  9. Clinical retrospective analysis of All-ceramic crowns and bridges with CAD/CAM Zirconia-base: A Four-year Follow up%CAD/CAM氧化锆全瓷冠桥随访4年的临床分析

    Institute of Scientific and Technical Information of China (English)

    孙凤; 张相皡; 晁春良; 杜阳; 李祎

    2011-01-01

    Objective: To evaluate the clinical performance of CAD/CAM zirconia all-ceramic crowns and fixed partial dentures (FPDs). Methods: 681 all-ceramic crowns or FPDs were fabricated for 267 patients. 562 restorations of 205 patients were clinically followed for 2-6 years. Recalls were made 3 months after cementation. Porcelain fracture performance was compared between restorations in anterior and premolar and molar. Using modified US Public Health Service criteria, judgments were made on marginal integrity and shade and color. Loose or dislodgement, fracture and breakage were reviewed in the annually follow up. Results: Chipping rate is 3.3 l%,Chipping of restorations in molars were higher than the restorations in premolars and in anterior teeth (x2 test, P< 0.01). Different technicians had significant influence (x2 test, P< 0.001) on color match of crowns, while different color of abutments did not (x2 test, P> 0.05). The authors rated 90.8% as good or better in regard to color match, 99.2% of the restorations were ranked as good or better on marginal integrity, Loose or dislodgement0.35%, 0% for fracture of Zirconia-based. Conclusion: Zirconia-based all-ceramic crowns with CAD/CAM show good marginal integrity and shade compatibility with nature teeth, with a clinically acceptable chipping rate, This material can be used in conventional and esthetic prosthetic dentistry and especially is the preferred esthetic restorations in case of abutment teeth discoloration. Further studies are needed to reduce the chipping in molars and to improve the marginal integrity of long bridges.%目的:回顾分析评价CAD/CAM氧化锆全瓷冠桥的修复效果.方法:为267位患者制做CAD/CAM氧化锆全瓷冠或桥681件,随访了205例患者的562件全瓷冠桥,随访时间2-6年.对修复体的崩瓷、全瓷冠的颜色与修复体的边缘密合度进行评价.结果:CAD/CAM氧化锆全瓷冠的崩瓷率3.31%,与修复体部位有明显相关性(P<0.01),不

  10. Fracture strength of all-ceramic restorations after fatigue loading

    Science.gov (United States)

    Baladhandayutham, Balasudha

    Fracture strength of monolithic and bilayered LAVA and e. max lower molar crowns after load cycling was measured and compared. The study included three groups (n = 8) from LAVA zirconia and three groups from e. max lithium disilicate to compare influences of different layers, thicknesses and manufacturing techniques. Prefabricated anatomically designed crowns were cemented to dies made from Z 100 composite resin using Rely X Luting Plus resin modified glass ionomer cement. Cemented crowns were stored at 37° C for 24 hours then cyclic loaded to test fatigue properties. The crowns were loaded to 200,000 cycles at 25N at a rate of 40 cycles / minute to simulate oral function. Subsequently, fracture properties for each group were measured using an Instron Universal Testing machine. Microscopic evaluation of the surface of fatigued samples did not reveal micro-cracks at the end of 50,000 cycles but minor wear facets were observed at the site of contact from the steatite ball antagonist. Crowns from LAVA bilayered groups showed step by step fractures while crowns from all other groups fractured as a single event as observed by the high speed camera. Zirconia bilayered crowns showed the highest loads to fracture while lithium disilicate monolithic crowns showed the lowest, within the limitations of the study. The study also showed that monolithic zirconia crowns of 0.6mm thickness resulted in relatively high magnitude for forces at fracture.

  11. Dynamically compacted all-ceramic lithium-ion batteries

    Science.gov (United States)

    Jak, Michiel J. G.; Ooms, Frans G. B.; Kelder, Erik M.; Legerstee, Waiter J.; Schoonman, Joop; Weisenburger, Alfons

    This paper deals with a cell design and a unique manufacturing process for all solid-state lithium-ion batteries. Detailed analyses of the manufacturing of the components for such a battery and the compaction of the green battery are presented. The electrodes were made of coatings of LiMn 2O 4 on metal foils. The electrolyte was a free-standing foil of the ceramic electrolyte Li-doped BPO 4 in a polymer matrix. The different layers were wound and compacted by using magnetic pulse compaction. Several characteristics of the compacted batteries are presented.

  12. Marginal Integrity of Glass Ionomer and All Ceramic Restorations

    Science.gov (United States)

    2015-06-01

    crowns and orthodontic bands (Croll & Helpin, 1994).Another useful application of GI is as a liner under direct restorations (Davidson, 1994). GI...effect adjacent to the margins of indirect restorations (Tantbirojn, 1997). Recurrent decay is a major cause of failure of dental restorations

  13. Fracture Analysis of an All-Ceramic Bearing System

    Science.gov (United States)

    1994-09-01

    Alpha Optical Systems, Inc., 1611 Government Street, Ocean Springs, MS 39564 1 Andre Ezis, Cercom, Inc., 1960 Watson Way, Vista, CA 92083 1 Robert Feest...David R. Breton 1 Sid 0. Davis 1 Edward R. Schillemat, Jr. 1 Barry O’Dwyer Director, U.S. Army Research Laboratory, Watertown, MA 02172-0001 2 ATTN: AMSRL-OP-WT-IS, Technical Library 10 Authors 32

  14. Comparison of the marginal fit of two kinds of all-ceramic and Au-Pt based porcelain-fused-metal crown systems%两种全瓷系统与金铂合金PFM冠边缘适合性的实验研究

    Institute of Scientific and Technical Information of China (English)

    李永斌; 孙迎春; 韦荣智; 包玮玮

    2012-01-01

    Objective: This study was performed to evaluate two ceramic and PFM crown systems for their accuracy of marginal fit. Methods: A total of 30 experimental crowns, the first molar of mandibular, were fabricated from two all-ceramic systems (IPS e.max and VITA In-Ceram Zirconia) and Au-Pt PFM systems (n=10). All restorations were delivered to prefabricated stone dies with composite resin cement. Gap widths were measured by light microscopy (magnificationx200). Intergroup differences were analyzed by one-way ANOVA. Results: The results showed there were significant differences for the marginal gap widths (F=2488.6, P<0.05). IPS e.max system seemed to have the smallest gap width, even better than Au-Pt PFM, while VITA In-Ceram Zirconia had the largest. Conclusion: IPS e.max system combined with composite resin cement has excellent marginal fit, which indicated that all-ceramic restorations were acceptable for clinical use regarding to marginal fit.%目的:比较两种全瓷系统与金-铂合金烤瓷熔附金属全冠(Porcelain-fused-to-metal Crown,PFM)的边缘适合性,为临床修复材料的选择提供参考依据.方法:30个右下第一磨牙的标准预备体石膏模型随机分为3组(n=10),分别制作IPSe.max,VITA In-Ceram Zirconia和金-铂合金PFM全冠修复体,树脂粘接剂粘固后,200倍光学显微镜下测量冠边缘间隙大小.结果:三组材料制作的修复体边缘间隙大小差异有统计学意义(F=2488.6,P<0.05),边缘间隙由小到大依次为IPSe.max,金-铂合金PFM,VITA In-Ceram Zirconia.并且各组间差异均有统计学意义(P<0.05).结论:IPS e.max全瓷修复体用树脂水门汀粘接后,边缘适合性良好,优于传统的PFM修复.全瓷修复体的边缘适合性符合临床应用要求.

  15. PES and WES evaluation of CAD/CAM custom abutments and all ceramic crowns in the anterior teeth area%红、白美学评价 CAD/CAM 个性化基台与全瓷冠在前牙区的应用

    Institute of Scientific and Technical Information of China (English)

    张晓真; 周国兴; 戴文雍; 赵毅; 邱憬; 王洁; 汤春波

    2013-01-01

    Objective:To investigate the clinic application of computer aided design&computer aided manufacturing ( CAD/CAM) custom abutments and all ceramic crowns and evaluate their esthetic effect in the anterior teeth area according to the assessment criteria Pink Esthetic Score ( PES ) and White Esthetic Score ( WES ) .Methods:Totally 73 CAD/CAM custom abutments and all ceramic crowns were used in 51 implant-supported prosthesis cases .The esthetic prosthetic effect was evaluated according to the assessment cri-teria PES and WES.Results:The 3-month-follow-up results of totally 73 CAD/CAM custom abutments and all ceramic crowns of 51 pa-tients:the percentage of the PES scores of 10,8-9,6-7 and≤5 was 9.59%,71.23%,17.81%,and 1.37%,respectively;the percent-age of the WES scores of 10,8-9,6-7 and ≤5 was 39.73%,60.27%,0%,and 0%,respectively.The 6-month-follow-up results: the percentage of the PES scores of 10,8-9,6-7 and≤5 was 8.22%,69.86%,17.81%,and 4.11%,respectively;the percentage of the WES scores of 10,8-9,6-7 and≤5 was 36.99%,61.64%,1.37%,and 0%,respectively.The 1-year-follow-up results:the percentage of the PES scores of 10,8-9,6-7 and≤5 was 5.48%,68.49%,20.55%,and 5.48%,respectively;the percentage of the WES scores of 10,8-9,6-7 and ≤5 was 31.51%,64.38%,4.11%,and 0%,respectively.During the follow-up of 1 to 3 years,there was only one abutment got fractured when the torque control was installed ,and one loosened during observation .In all cases,the gingivae were in healthy condition ,and no further obvious gingival retreat or periimplantitis occurred .Conclusions:PES and WES are objective ,integrat-ed and comparable .CAD/CAM custom abutments and all ceramic crowns have good biocompatibility and chemical stability ,and can be more widely used in the anterior teeth area .However,their long term effects need to be confirmed by further follow-up.%目的:研究计算机辅助设计及计算机辅助制作( CAD/CAM )个性化基台及全瓷冠的临床

  16. 有限元法分析不同粘接剂对全瓷冠应力分布的影响%Effect of different bonding agents on the stress distribution of all-ceramic crown by three-dimension finite element analysis

    Institute of Scientific and Technical Information of China (English)

    李冰; 张晔; 武秀萍; 邓菁菁; 吴婷婷; 张并生

    2014-01-01

    目的:探讨不同种类粘接剂对双层结构的全瓷冠及粘接剂应力分布的影响,为临床修复设计提供依据。方法利用螺旋CT断层图像,构建双层结构的全瓷冠(核瓷层和饰瓷层)、粘接剂层、牙体组织、牙根、牙周膜和牙槽骨6部分的三维有限元模型,设计垂直集中载荷600N的加载方式,分析全瓷冠经3种不同粘接剂(Panavia,3M RelyX Unicem,3M RelyX Luting)粘固后,粘接剂层、核瓷层和饰瓷层的最大主应力分布。结果粘接层应力集中部位为近中颊侧肩台和腭侧面近牙合面部分。核瓷层应力主要集中在核瓷内部,饰瓷层应力主要集中在加载点附近。随着粘接材料弹性模量的增加,位于饰瓷层的最大主应力呈现出下降的趋势,而位于核瓷层和粘接层的最大主应力出现上升的趋势。结论全瓷冠在不同粘接材料粘固后受到力的作用时,最大主应力分布区域相对固定,但分布范围有向加载侧分布的趋势。在某些条件下,高弹性模量的粘接剂可能会降低全瓷冠崩瓷的发生,并在一定程度上降低核瓷层的抗折能力。%Objective To investigate the relationship between the bonding agents and the stress distribu-tion of all-ceramic crown and then provide the basis for clinical restoration design. Methods The tomography im-ages of spiral CT were used to construct the finite element analysis mode, which was composed of six parts:double layer structure of all-ceramic crown(include the core layer and the veneer layer), adhesive layer, tooth tissues, tooth root, periodontal ligament, and alveolar bone. The loading way was designed as follows:600N load was verti-cally concentrated, and ANSYS software was used to analyze the stress values of the core layer、the veneer layer and the adhesive layer with three bonding agents including the Panavia,the 3M RelyX Unicem and the3M RelyX Luting cement. Results The distribution

  17. The optical property of four different all-ceramic crowns on the light color core ND1 substructure%高明度 ND1代型材料表面4种全瓷冠光学特性比较

    Institute of Scientific and Technical Information of China (English)

    陈奕帆; 张琳; 刘长虹; 王剑

    2015-01-01

    目的:评估高明度 ND1代型材料表面4种全瓷底冠光学参数 CIE L*a*b*值、透射比,烧结 A2体瓷后与 A2色片色差ΔE。方法:制作 ND1色基牙,分别戴入 Procera 氧化铝、Procera 氧化锆、Lava 氧化锆、IPS E.max 低透铸瓷底冠,分光光度比色仪拍摄并在颈1/3、体1/3、切1/3随机选点测色。4组底冠烧结 A2体瓷粉后再戴入 ND1色基牙(总瓷层厚度控制1.5 mm),分光光度比色仪测色,数据进行单因素方差分析、Bonferroni 多重均数比较。结果:4组底冠均提高基牙的 L*值,彩度a*值下降、b*值变化不一致,多数组间 L*a*b*值有统计学差异。烧结体瓷后各组冠 L*值明显下降,彩度 a*、b*值上升。各部分与 A2总体色差减小(ΔE =1.27~4.17)。4组底冠透光率均值依次为 E.max-LT A2>Pro-Alu >Lava-Zir >Pro-Zir。结论:ND1基牙戴入 4组全瓷底冠后明度、彩度差异大。底冠烧结体瓷后明度差异减少,彩度差异较大。Lava-Zir 和IPS E.max 体瓷组色差超过临床可接受度。铸造陶瓷和氧化铝底冠通透性高于2种氧化锆底冠。%Objective:To evaluate the optical property of the light color core substructure ND1 overlaid by 4 different all-ceramic crowns respectively and to study the color difference between the crowns and target tab.Methods:Light color(ND1)substructures were made and were respectively tried in 4 groups of all-ceramic crowns (Procera alumina,Procera zirconia,Lava zirconia and IPS E.max glass-ceramic lithium disilicate-reinforced monolithic,n =10).The CIE L*,a*,b* values of the cervical part,body and incisal site of the samples were recorded and analyzed by a spectrophotometer before and after veneer.The color difference between the all-ceramic crowns and target A2 dentin tab was evaluated.The spectral integral transmittance of the 4 copings was measured by a spectrophotometer.Results:The L* values of the abutments was

  18. Probe tip heating assembly

    Science.gov (United States)

    Schmitz, Roger William; Oh, Yunje

    2016-10-25

    A heating assembly configured for use in mechanical testing at a scale of microns or less. The heating assembly includes a probe tip assembly configured for coupling with a transducer of the mechanical testing system. The probe tip assembly includes a probe tip heater system having a heating element, a probe tip coupled with the probe tip heater system, and a heater socket assembly. The heater socket assembly, in one example, includes a yoke and a heater interface that form a socket within the heater socket assembly. The probe tip heater system, coupled with the probe tip, is slidably received and clamped within the socket.

  19. Newnes electronics assembly handbook

    CERN Document Server

    Brindley, Keith

    2013-01-01

    Newnes Electronics Assembly Handbook: Techniques, Standards and Quality Assurance focuses on the aspects of electronic assembling. The handbook first looks at the printed circuit board (PCB). Base materials, basic mechanical properties, cleaning of assemblies, design, and PCB manufacturing processes are then explained. The text also discusses surface mounted assemblies and packaging of electromechanical assemblies, as well as the soldering process. Requirements for the soldering process; solderability and protective coatings; cleaning of PCBs; and mass solder/component reflow soldering are des

  20. All-ceramic resin-bonded bridge made of hot-pressed casting porcelain with improved tooth preparation:a two-year clinical observation%改良牙体预备的热压铸全瓷粘接桥2年临床观察研究

    Institute of Scientific and Technical Information of China (English)

    任嫒姝; 邱雨; 邓琳琳; 付钢

    2015-01-01

    Objective To observe the clinical effect of all-ceramic resin-bonded bridge made of hot-pressed casting porcelain with improved tooth preparation in patients losing one or two mandibular anterior teeth. Methods 32 patients received the treatment. 32 two-retainers all-ceramic resin-bonded bridges were made. The integrity of the restorations,secondary caries of the abutments and the shade in the margin of the retainers were observed at 3 months,6 months,1 year and 2 years after the treatment. Results No loose and break of the bonded bridges were found after 3 months and 6 months. One prosthesis lost bond after 1 year,and two prostheses lost bond after 2 years,but they still could be used after being re-bonded. No secondary caries on the abutment and shade in margin of the retain-ers were observed after 2 years. Their color matched the adjacent teeth excellently. The success rate was 90. 6%. Conclusions All-ce-ramic resin-bonded bridge made of hot-pressed casting porcelain with improved tooth preparation can obtain good restoration effect in patients losing one or two mandibular anterior teeth.%目的:观察临床中下颌前牙缺失2颗以内的患者,采用改良粘接桥牙体预备后,热压铸造全瓷粘接桥临床修复效果。方法32位患者共制作32件双翼下前牙热压铸造全瓷粘接桥,修复后3个月、6个月、1年和2年观察修复体的完整性,基牙的继发龋,边缘着色。结果3个月和6个月内32例患者中未出现脱落和折断病例,1年内出现1例脱落患者,2年内出现2例脱落患者,但均通过处理后再次完成粘接继续使用,所有病例在2年的观察期内均未发生继发龋和边缘着色,其颜色与邻牙相协调。整体修复成功率为90.6%。结论下前牙2颗以内缺失患者,采用改良粘接桥牙体预备后,热压铸造全瓷粘接桥修复,可以取得较好的临床修复效果。

  1. 数字化口腔修复(12)--CAD/CAM全瓷嵌体修复楔状缺损(附病例报告)%Digital restorative dentistry and prosthodontics (12)--Restoration of wedge-shaped defect by CAD/CAM all ceramic inlay (case report)

    Institute of Scientific and Technical Information of China (English)

    金地; 姚江武

    2016-01-01

    Objective:The clinical effects were observed on the restoration of wedge-shaped defect teeth by using two lithium silicate inlay by (computer aided design/computer aided manufacturing,CAD/CAM). Method:The clinical case was a patient who had a wedge-shaped defect teeth reached deep below free gingival margin, which was going to restore with all ceramic inlay by CAD/CAM. The clinical effect assessment was made after 6 and 12 months respectively, according to modified USPHS standard. Result:The results in each review stage showed that there were no undesirable effects such as fall off, fracture and cleav-age occurred on inlay. The clinical indexes had up to A class. Conclusion:Better clinical effect can be achieved in treating teeth with wedge-shaped defect using two lithium silicate inlay by CAD/CAM, but the long-term follow-up result still had to be fur-ther observed.%目的:观察计算机辅助设计和制作(CAD/CAM)二矽酸锂全瓷嵌体修复牙颈部缺损的临床疗效。方法:临床病例为1颗牙颈部继发龋坏深达龈下的患牙,采用CAD/CAM全瓷嵌体修复,按照改良的USPHS标准分别进行6个月和1年的临床疗效评价。结果:各个复查阶段:嵌体无脱落,折断、劈裂等不良现象,临床指标均达到A级指标。结论:CAD/CAM嵌体修复牙颈部楔状缺损是一种效果良好的修复方法。

  2. Efficacy and Long-term Prognosis of Zirconia All-ceramic Crown Plus Fiber Post for Repair of Ante-rior Teeth Complex Crown Root Fracture%氧化锆全瓷冠加纤维桩修复前牙复杂冠根折的疗效及远期预后分析

    Institute of Scientific and Technical Information of China (English)

    周凌燕; 毛艳; 苏宗佑; 陈俊文; 罗家威; 吕夏

    2016-01-01

    Objective To analyze the efficacy and long-term prognosis zirconia all-ceramic crown plus fiber post to repair anterior teeth complex crown root fracture.Methods From Feb.2008 to Jan.2010 in Affiliated Stomatology Hospital of Guangxi Medical University 110 patients for treatment of anterior teeth crown root fracture were included as research objects,and were divided into observation group and control group according to random number table method,55 cases each.The observation group adopted zirconia all-ceramic crown plus fiber post restoration treatment,an the control group adopted conventional orthodontic traction plus crown lengthening surgery for treatment.The tooth mobility,periodontal probing depth,gingival sulcus bleeding index of the two groups before and after treatment were compared,and 5 years of follow-up was done to compare the long-term prognosis.Results After treatment the tooth mobility,the sulcus bleeding index of the observation group were significantly lower than the control group [ ( 0.19 ±0.04 ) vs ( 0.40 ± 0.11),(0.78 ±0.16) vs (2.01 ±0.27),P <0.01],probing depth of the observation group was signifi-cantly higher than the control group[(5.99 ±0.14) mm vs (3.97 ±0.10) mm,P<0.01],the difference was statistically significant ( P <0.05 );the repair success rate of the observation group was significantly higher than the control group [92.73% (51/55) vs 54.55% (30/55)],the difference was statistically sig-nificant ( P <0.05 ) .Root fracture, secondary caries and periodontal disease incidence of the observation group were significantly lower than the control group [1.82%(1/55) vs 14.55%(8/55),1.82%(1/55) vs 9.09%(7/55),3.64%(2/55) vs 18.18%(10/55)],the differences were statistically significant(P<0.05).Conclusion Zirconia all-ceramic crowns plus fiber post has good clinical efficacy for anterior teeth complex crown root fracture,which can promote tooth mobility,probing depth,and improve sulcus bleeding index,with good long-term prognosis,thus is

  3. 磨牙全瓷冠断裂类型的力学实验与三维有限元分析研究%A comparative study of mechanical experiment and three-dimensional finite element analysis on fracture mode of all-ceramic molar crowns

    Institute of Scientific and Technical Information of China (English)

    王勤琴; 张骏; 赵克; 张新平

    2008-01-01

    Objective To investigate the influence of indenter diameter on fracture strength and fracture mode of IPS e. max all-ceramic crowns using mechanical experiments and three-dimensional finite element (3-DFE) method, to validate the 3-DFE model using mechanical experiments, and to provide a guideline for occlnsal surface design for IPS e. max all-ceramic crowns. Methods A 3-DFE model of an all-ceramic crown on a molar was established using ANSYS10.0 software. The 3-DFE crown was loaded occlusally at three points to simulate the contact points of a hemispherical indenter loading on the crown. Two indenter diameters (4 mm and 10 mm) were designed by changing loading point, load level and its direction. The stress distribution and the principal stress in the 3-DFE model were calculated. Meanwhile, IPS e. max ceramic crowns were made on a laboratory model and loaded with indenters. The diameters of the indenters were also 4 mm and 10 mm respectively. Fracture mode and fracture-resistance of the crowns were recorded. Results The principal stress increased as load increases for both small and large indenters. Stress concentrated in the central fossa of the 3-DFE crown when loaded with the small indenter. Stress concentration appeared in the middle area of the occlusal surface mesio-distally when 3-DFE crown was loaded with large indenter. The fracture-resistance load was 600 N to 700 N for 4 mm diameter indenter, and 2500 N to 2750 N for 10 mm diameter indenter. Mechanical experiments indicated the same results as those from 3-DFE analysis. Conclusions Both the three-dimensional finite element analysis and the mechanical experiment showed the same results. When loaded with 4 mm diameter indenter, fracture occured in the central fossa of the crown, however, 10 mm diameter indenter usually caused extensive crown damage.%通过力学实验和三维有限元研究不同直径半球形压头对全瓷冠断裂强度、断裂类型的影响,以期为临床全瓷冠(牙合)面形

  4. 全瓷材料的透明度及不同背景下色度学变化的实验研究%Experimental study on the transparency of different all-ceramic materials and their color changes under different backgrounds

    Institute of Scientific and Technical Information of China (English)

    周叶青; 顾新华

    2014-01-01

    Objective To evaluate the aesthetic outcomes of all-ceramic restorations by using four different porcelain materials on mimic-tetracycline pigmentation backgrounds. Methods The translucency parameters (TP) of four different all-ceramic restorations (IPS e.max, Cercon, Lava, and Girrbach) were measured under white and black back grounds by using Datacolor 600, and the TP of each group (n=8) was calculated. Five different mimic-tetracycline pigmentation teeth were printed with different colors by using a colorized printer as the prepared teeth backgrounds, under which the color para-meters of each group were measured. The color differences with a standard 2M2 sample were calculated. Results The TP values of the all-ceramic restorations were 15.67±0.58 for IPS e.max, 9.73±0.43 for Girrbach, 9.55±0.25 for Lava, and 7.56± 0.43 for Cercon. The TP value of the IPS e.max group was significantly higher than those of the other three groups (P<0.001). TheΔE of the IPS e.max group was 1.33 national bureau of standards (NBS) on the yellow background, and theΔE of the Lava and Girrbach groups were 0.75 NBS to 1.47 NBS on the mimic-tetracycline pigmentation backgrounds of gray, dark gray, dark red, and light red. Conclusion The IPS e.max group has favorable TP. IPS e.max shows better aesthetic effects than the others when restoring mimic-tetracycline pigmentation teeth (on yellow background). Lava and Girrbach show better aesthetic effects on mimic-tetracycline pigmentation teeth (on gray, dark gray, dark red, and light red backgrounds).%目的:比较4种全瓷材料修复体的透明度参数(TP)及其在模拟不同颜色的四环素染色牙背景下的色差ΔE,评价其美学修复效果。方法制作4种不同全瓷材料(包括IPS e. max、Cercon、Lava、Girrbach)的修复体样本(n=8),用Datacolor 600型分光测色仪测得每组样本在白色及黑色背景下的颜色参数,计算TP。用彩色打印机打印出黄、灰

  5. Polymer Directed Protein Assemblies

    NARCIS (Netherlands)

    van Rijn, Patrick

    2013-01-01

    Protein aggregation and protein self-assembly is an important occurrence in natural systems, and is in some form or other dictated by biopolymers. Very obvious influences of biopolymers on protein assemblies are, e. g., virus particles. Viruses are a multi-protein assembly of which the morphology is

  6. 数字化口腔修复(19)--激光切龈与CAD/CAM全瓷冠美学修复(附病例报告)%Digital restorative dentistry and prosthodontics (19)---Laser gingivectomy and esthetic restoration with CAD/CAM all ceramic crown(a case report)

    Institute of Scientific and Technical Information of China (English)

    华德攀; 姚江武

    2016-01-01

    目的:观察二极管激光修整前牙牙龈形态、龈沟深度及CEREC®椅旁计算机辅助设计与制造( computer aided design/computer aided manufacturing,CAD/CAM)全瓷冠美学修复的临床效果。方法:前牙12、21、22牙体缺损患者1例,二极管激光修整前牙牙龈形态、龈沟深度,并用CEREC®椅旁CAD/CAM行全瓷冠美学修复。6个月后采用改良USPHS标准对其短期的临床疗效进行评估。结果:二极管激光修整牙龈1周后开始呈粉红,质地韧,形态和龈沟深度协调;修复6个月后全瓷冠完整无折裂,未见继发龋;修复体边缘密合,固位、邻接良好,颜色美观。结论:激光切龈方法精确,创伤小,出血少,视野清晰,愈合快,患者容易接受。%Objective:To observe gingivectomy and the gingival sulcus depth by diode laser and the effect of all ce-ramic esthetic restoration via CEREC® chair-side CAD/CAM.Methods:One case with the anterior teeth defects have been operated gingicvectomy by diode laser.Then the anterior teeth were restored by chair-side all ceramic CAD/CAM and the short-term clinical effect was evaluated by modified united States Public Health Service( USPHS) standard after six months. Results:The gingiva and the gingival sulcus depth was harmonious with the prosthesis,which in place smoothly,marginal in-tegrity and has a good aesthetic effect after six months of the restoration.Conclusion:During operation laser cutting tissue,the treatment had the advantages of less bleeding,clear vision,less trauma,and rapid healing.Patient was satisfied with the effect of treatment.Moreover,the application of laser can improve the comfort level and reduce adverse reactions during in restora-tion process.

  7. 热压铸陶瓷二代(IPS-EMPRESS Ⅱ)与肩台瓷修复体颈缘效果三年临床评估%Comparison of the cervical margin fitness between IPS-Empress Ⅱ pressable all ceramic crowns and porcerlain fused to metal crowns with shoulder ceramic margin with 3 years' follow-up

    Institute of Scientific and Technical Information of China (English)

    刘朴; 孔敏; 代育桐

    2009-01-01

    目的 评估比较热压铸瓷二代(IPS-Empress)修复体和肩台瓷(IPS-Margin)金瓷修复体颈缘的临床效果.方法 临床为63例患者的90颗患牙进行IPS-Empress热压铸陶瓷全冠修复,为98例患者的129颗患牙进行有肩台瓷的PFM全冠修复.永久性粘结后6个月和36个月复诊,比较修复体颈缘临床效果.结果 在比较后发现铸瓷全冠和肩台瓷在牙龈变色,颈缘适合度,牙龈炎症三方面均无显著性差异.结论 肩台瓷修复体与全瓷修复体能达到相同的颈缘效果.对想解决颈缘问题又无力支付全瓷冠的修复患者来说,肩台瓷不失为一种好的选择.%Objective To evaluate and compare the cervical margin fitness and gingival discoloration between IPS-EMPRESS Ⅱ all ceramic crown and PFM crown with shoulder ceramic margin.Methods Ninty teeth of 63 patients were restored with IPS-EMPRESS Ⅱ pressable ceramic crowns and 129 teeth of 98 patients were restored with PFM crowns with shoulder ceramic margins. The marginal fitness, gingival discoloration, and gingival health of all these restorations were examined at 6 months, and 36 months after permanent luting respectively.Results There was no statistical difference for gingival discoloration, marginal fitness and gingival health between IPS-Empress II and PFM crown with shoulder ceramic margin (P>0.05).Conclusion Both PFM crown with shoulder ceramic margin and IPS-Empress Ⅱ ceramic crown satisfied the esthetic demand in the cervical margin area. PFM crown with shoulder ceramic margin is a reliable and ideal choice for the low-budget patients with the desire of esthetic cervical margin.

  8. Sensor mount assemblies and sensor assemblies

    Science.gov (United States)

    Miller, David H [Redondo Beach, CA

    2012-04-10

    Sensor mount assemblies and sensor assemblies are provided. In an embodiment, by way of example only, a sensor mount assembly includes a busbar, a main body, a backing surface, and a first finger. The busbar has a first end and a second end. The main body is overmolded onto the busbar. The backing surface extends radially outwardly relative to the main body. The first finger extends axially from the backing surface, and the first finger has a first end, a second end, and a tooth. The first end of the first finger is disposed on the backing surface, and the tooth is formed on the second end of the first finger.

  9. Soldering in electronics assembly

    CERN Document Server

    Judd, Mike

    2013-01-01

    Soldering in Electronics Assembly discusses several concerns in soldering of electronic assemblies. The book is comprised of nine chapters that tackle different areas in electronic assembly soldering. Chapter 1 discusses the soldering process itself, while Chapter 2 covers the electronic assemblies. Chapter 3 talks about solders and Chapter 4 deals with flux. The text also tackles the CS and SC soldering process. The cleaning of soldered assemblies, solder quality, and standards and specifications are also discussed. The book will be of great use to professionals who deal with electronic assem

  10. Effect of the veneer porcelain thickness on the color and transmissivity of IPS e.max all-ceramic restoration%饰面瓷厚度对IPS e.max全瓷修复体颜色及透射率的影响

    Institute of Scientific and Technical Information of China (English)

    李莉; 刘晓艳

    2014-01-01

    目的:探讨不同饰面瓷厚度对IPS e.max全瓷修复体颜色及透射率的影响,发现规律,为完善全瓷修复体制作工艺及临床实践提供参考依据。方法将IPS e.max铸瓷材料制作成核瓷厚度为0.8 mm、牙本质瓷厚度为1.2 mm的总厚度为2.0 mm、直径为15 mm的圆盘状试件。试件表面每次均匀磨去0.2 mm,至其厚度为1.4 mm。每一厚度均测量其L*a*b*颜色参数及透射率,并对结果进行统计学分析。结果随着饰面瓷厚度的增加,IPS e.max全瓷修复体的L*值呈降低趋势,a*值和b*值无明显变化趋势;ΔE值呈降低趋势,且各厚度组间色差ΔE均大于1.5;TP值逐渐降低,CR值逐渐增加,可见光积分透射率逐渐降低。结论随着饰面瓷厚度的增加,IPS e.max全瓷修复体的色调无明显变化,明度、半透性和可见光积分透射率逐渐降低,对背景颜色的遮盖能力逐渐增强。%Objective Study the influence of different veneer porcelain thickness to the color and transmissivity of IPS e.max all-ceramic restoration, discover the rule, in order to get vivid color and ideal restoration effect. Methods Make IPS e.max into discal specimens with 15mm in diameter and 2.0mm thick including 0.8mm thick nuclear porcelain and 1.2mm dentin porcelain. And then they are grinded 0.2 mm each time, to the thickness of 1.4 mm. Measure the L*a*b* parameters and transmissivity of each thickness,and proceed statistical analysis. Results With dentin porcelain thickness increasing, the L*values reduce, the a*values and b*values of IPS e.max have no obvious change trend;ΔE and TP values gradually reduce, while CR values increase, the transmissivity gradually reduce. Conclusion With the dentin porcelain thickness increasing,value, translucency and transmissivities gradually reduce while hue has no obvious change.

  11. Effects of try-in paste and luting agent on the resultant color of all-ceramic veneers%试色糊剂和黏结剂对瓷贴面修复体颜色影响的一致性研究

    Institute of Scientific and Technical Information of China (English)

    徐镔亭; 李清; 李蓉; 王贻宁

    2011-01-01

    Objective The purposes of this study was to investigate the effects of luting agents on the resultant color of IPS e.max all-ceramic veneer restorations, and to evaluate the similarity of try-in pastes and the corresponding luting agents on the final color.Methods Disc-shaped ceramic specimens were fabricated and seated on four shades of resin specimens to mimic the complex of ceramic veneer laying on tooth substrates.Try-in pastes and luting agents(Shades of TR, B0.5, A1, A3, WO) were applied into the inter-layer of ceramic and resin specimens,respectively.The color of the combinations was measured using a spectrophotometer and subsequently converted to CIE L*a*b* values Color changes after luting agent applied, and between try-in paste and corresponding luting agent were calculated and registered as △Eremin and △Epatke-remin Results △Emin value of A2, A3 backgrounds was more than 1.0.△Eremin value of A4, A5 backgrounds was less than 1.0.The △Epatke-remin value of A3 backgrounds was more than 1.0, whereas, A2 was less than 1.0(except for shade WO).The △Epatke-remin value of shade WO was significantly different from other shades of luting agents.Conclusion The color of ceramic veneer restorations were affected by luting agents with A2, and A3 background colors.The agreement of the try-in paste and the corresponding luting agent was excellent for A2 background(except for WO).%目的 观察试色糊剂和相应色号树脂黏结剂对IPS e.max瓷贴面修复体最终颜色的影响及影响的一致性.方法 叠加IPS e.max热压铸瓷片和复合树脂块模拟瓷贴面覆盖预备后的基牙.在瓷试样和树脂试样之间分别加入试色糊剂和树脂黏结剂(TR、B0.5、A1、A3和WO色)形成试样复合体.使用分光光谱仪测量复合体颜色,并分别用△Ereain代表使用黏结剂前后的色差和△Epaste-reain代表使用试色糊剂与使用黏结剂的色差.结果 基底为A2、A3色时,△Ereain值大于1.0,A4、A5

  12. ex vivo DNA assembly

    Directory of Open Access Journals (Sweden)

    Adam B Fisher

    2013-10-01

    Full Text Available Even with decreasing DNA synthesis costs there remains a need for inexpensive, rapid and reliable methods for assembling synthetic DNA into larger constructs or combinatorial libraries. Advances in cloning techniques have resulted in powerful in vitro and in vivo assembly of DNA. However, monetary and time costs have limited these approaches. Here, we report an ex vivo DNA assembly method that uses cellular lysates derived from a commonly used laboratory strain of Escherichia coli for joining double-stranded DNA with short end homologies embedded within inexpensive primers. This method concurrently shortens the time and decreases costs associated with current DNA assembly methods.

  13. Target Assembly Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Target Assembly Facility integrates new armor concepts into actual armored vehicles. Featuring the capability ofmachining and cutting radioactive materials, it...

  14. Perspective: Geometrically frustrated assemblies

    Science.gov (United States)

    Grason, Gregory M.

    2016-09-01

    This perspective will overview an emerging paradigm for self-organized soft materials, geometrically frustrated assemblies, where interactions between self-assembling elements (e.g., particles, macromolecules, proteins) favor local packing motifs that are incompatible with uniform global order in the assembly. This classification applies to a broad range of material assemblies including self-twisting protein filament bundles, amyloid fibers, chiral smectics and membranes, particle-coated droplets, curved protein shells, and phase-separated lipid vesicles. In assemblies, geometric frustration leads to a host of anomalous structural and thermodynamic properties, including heterogeneous and internally stressed equilibrium structures, self-limiting assembly, and topological defects in the equilibrium assembly structures. The purpose of this perspective is to (1) highlight the unifying principles and consequences of geometric frustration in soft matter assemblies; (2) classify the known distinct modes of frustration and review corresponding experimental examples; and (3) describe outstanding questions not yet addressed about the unique properties and behaviors of this broad class of systems.

  15. Extending reference assembly models

    DEFF Research Database (Denmark)

    Church, Deanna M.; Schneider, Valerie A.; Steinberg, Karyn Meltz;

    2015-01-01

    The human genome reference assembly is crucial for aligning and analyzing sequence data, and for genome annotation, among other roles. However, the models and analysis assumptions that underlie the current assembly need revising to fully represent human sequence diversity. Improved analysis tools...

  16. Assembly of primary cilia

    DEFF Research Database (Denmark)

    Pedersen, Lotte B; Veland, Iben R; Schrøder, Jacob M

    2008-01-01

    in primary cilia assembly or function have been associated with a panoply of disorders and diseases, including polycystic kidney disease, left-right asymmetry defects, hydrocephalus, and Bardet Biedl Syndrome. Here we provide an up-to-date review focused on the molecular mechanisms involved in the assembly...

  17. Assembly: a resource for assembled genomes at NCBI.

    Science.gov (United States)

    Kitts, Paul A; Church, Deanna M; Thibaud-Nissen, Françoise; Choi, Jinna; Hem, Vichet; Sapojnikov, Victor; Smith, Robert G; Tatusova, Tatiana; Xiang, Charlie; Zherikov, Andrey; DiCuccio, Michael; Murphy, Terence D; Pruitt, Kim D; Kimchi, Avi

    2016-01-04

    The NCBI Assembly database (www.ncbi.nlm.nih.gov/assembly/) provides stable accessioning and data tracking for genome assembly data. The model underlying the database can accommodate a range of assembly structures, including sets of unordered contig or scaffold sequences, bacterial genomes consisting of a single complete chromosome, or complex structures such as a human genome with modeled allelic variation. The database provides an assembly accession and version to unambiguously identify the set of sequences that make up a particular version of an assembly, and tracks changes to updated genome assemblies. The Assembly database reports metadata such as assembly names, simple statistical reports of the assembly (number of contigs and scaffolds, contiguity metrics such as contig N50, total sequence length and total gap length) as well as the assembly update history. The Assembly database also tracks the relationship between an assembly submitted to the International Nucleotide Sequence Database Consortium (INSDC) and the assembly represented in the NCBI RefSeq project. Users can find assemblies of interest by querying the Assembly Resource directly or by browsing available assemblies for a particular organism. Links in the Assembly Resource allow users to easily download sequence and annotations for current versions of genome assemblies from the NCBI genomes FTP site.

  18. Self-assembled nanostructures

    CERN Document Server

    Zhang, Jin Z; Liu, Jun; Chen, Shaowei; Liu, Gang-yu

    2003-01-01

    Nanostructures refer to materials that have relevant dimensions on the nanometer length scales and reside in the mesoscopic regime between isolated atoms and molecules in bulk matter. These materials have unique physical properties that are distinctly different from bulk materials. Self-Assembled Nanostructures provides systematic coverage of basic nanomaterials science including materials assembly and synthesis, characterization, and application. Suitable for both beginners and experts, it balances the chemistry aspects of nanomaterials with physical principles. It also highlights nanomaterial-based architectures including assembled or self-assembled systems. Filled with in-depth discussion of important applications of nano-architectures as well as potential applications ranging from physical to chemical and biological systems, Self-Assembled Nanostructures is the essential reference or text for scientists involved with nanostructures.

  19. Constrained space camera assembly

    Science.gov (United States)

    Heckendorn, Frank M.; Anderson, Erin K.; Robinson, Casandra W.; Haynes, Harriet B.

    1999-01-01

    A constrained space camera assembly which is intended to be lowered through a hole into a tank, a borehole or another cavity. The assembly includes a generally cylindrical chamber comprising a head and a body and a wiring-carrying conduit extending from the chamber. Means are included in the chamber for rotating the body about the head without breaking an airtight seal formed therebetween. The assembly may be pressurized and accompanied with a pressure sensing means for sensing if a breach has occurred in the assembly. In one embodiment, two cameras, separated from their respective lenses, are installed on a mounting apparatus disposed in the chamber. The mounting apparatus includes means allowing both longitudinal and lateral movement of the cameras. Moving the cameras longitudinally focuses the cameras, and moving the cameras laterally away from one another effectively converges the cameras so that close objects can be viewed. The assembly further includes means for moving lenses of different magnification forward of the cameras.

  20. Dynamic nanoparticle assemblies.

    Science.gov (United States)

    Wang, Libing; Xu, Liguang; Kuang, Hua; Xu, Chuanlai; Kotov, Nicholas A

    2012-11-20

    Although nanoparticle (NP) assemblies are at the beginning of their development, their unique geometrical shapes and media-responsive optical, electronic, and magnetic properties have attracted significant interest. Nanoscale assembly bridges multiple levels of hierarchy of materials: individual nanoparticles, discrete molecule-like or virus-like nanoscale agglomerates, microscale devices, and macroscale materials. The capacity to self-assemble can greatly facilitate the integration of nanotechnology with other technologies and, in particular, with microscale fabrication. In this Account, we describe developments in the emerging field of dynamic NP assemblies, which are spontaneously form superstructures containing more than two inorganic nanoscale particles that display the ability to change their geometrical, physical, chemical, and other attributes. In many ways, dynamic assemblies can represent a bottleneck in the "bottom-up" fabrication of NP-based devices because they can produce a much greater variety of assemblies, but they also provide a convenient tool for variation of geometries and dimensions of nanoparticle assemblies. Superstructures of NPs (and those held together by similar intrinsic forces)are classified into two groups: Class 1 where media and external fields can alter shape, conformation, and order of stable super structures with a nearly constant number of NPs or Class 2 where the total number of NPs changes, while the organizational motif in the final superstructure remains the same. The future development of successful dynamic assemblies requires understanding the equilibrium in dynamic NP systems. The dynamic nature of Class 1 assemblies is associated with the equilibrium between different conformations of a superstructure and is comparable to the isomerization in classical chemistry. Class 2 assemblies involve the formation or breakage of linkages between the NPs, which is analogous to the classical chemical equilibrium for the formation of

  1. The application of all ceramic restoration to correct anterior mild malocclusion in adult and its clinical aesthetic restoration%全瓷修复技术在矫正成人轻度前牙错畸形及临床美学修复中的应用

    Institute of Scientific and Technical Information of China (English)

    邱伟江; 郑学汜; 刘智飞; 孟秋菊

    2014-01-01

    . Experimental group were treated by repairing the all-ceramic restoration, control group were treated by nickel-chromium alloy PFM crown restoration. Compared two groups of 6 months after treatment in patients with visual analogue scale (VAS) satisfaction score, before and 6, 12 months after treatment gingival index and 6 months after treatment restoration the revised standard rating of the American Public Health Association (USPHS score). Result After treatment in experimental group patients with the cut end of the trial defect, tooth surface defect and deformity of small teeth, tooth clearance, tooth staining and total satisfaction VAS scores were signiifcantly higher than that of control group (P<0.05). 6 months after treatment in both groups of GI were signiifcantly higher than before treatment, 12 months treatment after of GI were signiifcantly less than 6 months after treatment (P < 0.05);experimeutal group 6 months and 12 months after treatment of GI were signiifcantly lower than control group (P<0.01). Experimental group after treatment for 6 months ago dental restoration edge coloring and ift score was signiifcantly higher than control group (P < 0.05). Conclusion The whole porcelain restoration technique before orthodontic adult mild tooth occlusal wrong deformity curative effect is distinct, better than that of nickel-chromium alloy PFM crowns, suitable for mild crowded displacement before, bad bite or tooth discoloration of mild deformity, worthy of clinical application.

  2. Modular assembled space telescope

    Science.gov (United States)

    Feinberg, Lee D.; Budinoff, Jason; MacEwen, Howard; Matthews, Gary; Postman, Marc

    2013-09-01

    We present a new approach to building a modular segmented space telescope that greatly leverages the heritage of the Hubble Space Telescope and the James Webb Space Telescope. The modular design in which mirror segments are assembled into identical panels allows for economies of scale and for efficient space assembly that make a 20-m aperture approach cost effective. This assembly approach can leverage NASA's future capabilities and has the power to excite the public's imagination. We discuss the science drivers, basic architecture, technology, and leveraged NASA infrastructure, concluding with a proposed plan for going forward.

  3. DC source assemblies

    Science.gov (United States)

    Campbell, Jeremy B; Newson, Steve

    2013-02-26

    Embodiments of DC source assemblies of power inverter systems of the type suitable for deployment in a vehicle having an electrically grounded chassis are provided. An embodiment of a DC source assembly comprises a housing, a DC source disposed within the housing, a first terminal, and a second terminal. The DC source also comprises a first capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the first terminal. The DC source assembly further comprises a second capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the second terminal.

  4. Designing Assemblies Of Plates

    Science.gov (United States)

    Williams, F. W.; Kennedy, D.; Butler, R.; Aston, G.; Anderson, M. S.

    1992-01-01

    VICONOPT calculates vibrations and instabilities of assemblies of prismatic plates. Designed for efficient, accurate analysis of buckling and vibration, and for optimum design of panels of composite materials. Written in FORTRAN 77.

  5. Polymer Directed Protein Assemblies

    Directory of Open Access Journals (Sweden)

    Patrick van Rijn

    2013-05-01

    Full Text Available Protein aggregation and protein self-assembly is an important occurrence in natural systems, and is in some form or other dictated by biopolymers. Very obvious influences of biopolymers on protein assemblies are, e.g., virus particles. Viruses are a multi-protein assembly of which the morphology is dictated by poly-nucleotides namely RNA or DNA. This “biopolymer” directs the proteins and imposes limitations on the structure like the length or diameter of the particle. Not only do these bionanoparticles use polymer-directed self-assembly, also processes like amyloid formation are in a way a result of directed protein assembly by partial unfolded/misfolded biopolymers namely, polypeptides. The combination of proteins and synthetic polymers, inspired by the natural processes, are therefore regarded as a highly promising area of research. Directed protein assembly is versatile with respect to the possible interactions which brings together the protein and polymer, e.g., electrostatic, v.d. Waals forces or covalent conjugation, and possible combinations are numerous due to the large amounts of different polymers and proteins available. The protein-polymer interacting behavior and overall morphology is envisioned to aid in clarifying protein-protein interactions and are thought to entail some interesting new functions and properties which will ultimately lead to novel bio-hybrid materials.

  6. Human Assisted Assembly Processes

    Energy Technology Data Exchange (ETDEWEB)

    CALTON,TERRI L.; PETERS,RALPH R.

    2000-01-01

    Automatic assembly sequencing and visualization tools are valuable in determining the best assembly sequences, but without Human Factors and Figure Models (HFFMs) it is difficult to evaluate or visualize human interaction. In industry, accelerating technological advances and shorter market windows have forced companies to turn to an agile manufacturing paradigm. This trend has promoted computerized automation of product design and manufacturing processes, such as automated assembly planning. However, all automated assembly planning software tools assume that the individual components fly into their assembled configuration and generate what appear to be a perfectly valid operations, but in reality the operations cannot physically be carried out by a human. Similarly, human figure modeling algorithms may indicate that assembly operations are not feasible and consequently force design modifications; however, if they had the capability to quickly generate alternative assembly sequences, they might have identified a feasible solution. To solve this problem HFFMs must be integrated with automated assembly planning to allow engineers to verify that assembly operations are possible and to see ways to make the designs even better. Factories will very likely put humans and robots together in cooperative environments to meet the demands for customized products, for purposes including robotic and automated assembly. For robots to work harmoniously within an integrated environment with humans the robots must have cooperative operational skills. For example, in a human only environment, humans may tolerate collisions with one another if they did not cause much pain. This level of tolerance may or may not apply to robot-human environments. Humans expect that robots will be able to operate and navigate in their environments without collisions or interference. The ability to accomplish this is linked to the sensing capabilities available. Current work in the field of cooperative

  7. Photovoltaic self-assembly.

    Energy Technology Data Exchange (ETDEWEB)

    Lavin, Judith; Kemp, Richard Alan; Stewart, Constantine A.

    2010-10-01

    This late-start LDRD was focused on the application of chemical principles of self-assembly on the ordering and placement of photovoltaic cells in a module. The drive for this chemical-based self-assembly stems from the escalating prices in the 'pick-and-place' technology currently used in the MEMS industries as the size of chips decreases. The chemical self-assembly principles are well-known on a molecular scale in other material science systems but to date had not been applied to the assembly of cells in a photovoltaic array or module. We explored several types of chemical-based self-assembly techniques, including gold-thiol interactions, liquid polymer binding, and hydrophobic-hydrophilic interactions designed to array both Si and GaAs PV chips onto a substrate. Additional research was focused on the modification of PV cells in an effort to gain control over the facial directionality of the cells in a solvent-based environment. Despite being a small footprint research project worked on for only a short time, the technical results and scientific accomplishments were significant and could prove to be enabling technology in the disruptive advancement of the microelectronic photovoltaics industry.

  8. In vitro kinetochore assembly

    Science.gov (United States)

    Miell, Matthew D D; Straight, Aaron F

    2016-01-01

    The kinetochore is the primary site of interaction between chromosomes and microtubules of the mitotic spindle during chromosome segregation. The kinetochore is a complex of more than 100 proteins that transiently assemble during mitosis at a single defined region on each chromosome, known as the centromere. Kinetochore assembly and activity must be tightly regulated to ensure proper microtubule interaction and faithful chromosome segregation because perturbation of kinetochores often results in aneuploidy and cell lethality. As such, cell free and reconstituted systems to analyze kinetochore formation and function are invaluable in probing the biochemical activities of kinetochores. In vitro approaches to studying kinetochores have enabled the manipulation of kinetochore protein structure, function, interactions and regulation that are not possible in cells. Here we outline a cell-free approach for the assembly of centromeres and recruitment of functional kinetochores that enables their manipulation and analysis. PMID:27193846

  9. Assembling Sustainable Territories

    DEFF Research Database (Denmark)

    Vandergeest, Peter; Ponte, Stefano; Bush, Simon

    2015-01-01

    The authors show how certification assembles ‘sustainable’ territories through a complex layering of regulatory authority in which both government and nongovernment entities claim rule-making authority, sometimes working together, sometimes in parallel, sometimes competitively. It is argued...... that territorialisation is accomplished not just through (re)defining bounded space, but more broadly through the assembling of four elements: space, subjects, objects, and expertise. Four case studies of sustainability certification in seafood are analyzed to show that ‘green gabbing’ is not necessarily the central...... dynamic in assembling sustainable territories, and that certification always involves state agencies in determining how the key elements that comprise it are defined. Whereas some state agencies have been suspicious of sustainability certification, others have embraced it or even used it to extend...

  10. Power module assembly

    Science.gov (United States)

    Campbell, Jeremy B [Torrance, CA; Newson, Steve [Redondo Beach, CA

    2011-11-15

    A power module assembly of the type suitable for deployment in a vehicular power inverter, wherein the power inverter has a grounded chassis, is provided. The power module assembly comprises a conductive base layer electrically coupled to the chassis, an insulating layer disposed on the conductive base layer, a first conductive node disposed on the insulating layer, a second conductive node disposed on the insulating layer, wherein the first and second conductive nodes are electrically isolated from each other. The power module assembly also comprises a first capacitor having a first electrode electrically connected to the conductive base layer, and a second electrode electrically connected to the first conductive node, and further comprises a second capacitor having a first electrode electrically connected to the conductive base layer, and a second electrode electrically connected to the second conductive node.

  11. Blade attachment assembly

    Science.gov (United States)

    Garcia-Crespo, Andres Jose; Delvaux, John McConnell; Miller, Diane Patricia

    2016-05-03

    An assembly and method for affixing a turbomachine rotor blade to a rotor wheel are disclosed. In an embodiment, an adaptor member is provided disposed between the blade and the rotor wheel, the adaptor member including an adaptor attachment slot that is complementary to the blade attachment member, and an adaptor attachment member that is complementary to the rotor wheel attachment slot. A coverplate is provided, having a coverplate attachment member that is complementary to the rotor wheel attachment slot, and a hook for engaging the adaptor member. When assembled, the coverplate member matingly engages with the adaptor member, and retains the blade in the adaptor member, and the assembly in the rotor wheel.

  12. Integrated magnetic transformer assembly

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to an integrated magnetics transformer assembly comprising a first magnetically permeable core forming a first substantially closed magnetic flux path and a second magnetically permeable core forming a second substantially closed magnetic flux path. A first input...... inductor winding is wound around a first predetermined segment of the first magnetically permeable core and a second input inductor winding is wound around a first predetermined segment of the second magnetically permeable core. The integrated magnetics transformer assembly further comprises a first output......-winding of the first output inductor winding and the first half-winding of the second output inductor winding are configured to produce aligned, i.e. in the same direction, magnetic fluxes through the first substantially closed magnetic flux path. The integrated magnetics transformer assembly is well- suited for use...

  13. Self assembling proteins

    Science.gov (United States)

    Yeates, Todd O.; Padilla, Jennifer; Colovos, Chris

    2004-06-29

    Novel fusion proteins capable of self-assembling into regular structures, as well as nucleic acids encoding the same, are provided. The subject fusion proteins comprise at least two oligomerization domains rigidly linked together, e.g. through an alpha helical linking group. Also provided are regular structures comprising a plurality of self-assembled fusion proteins of the subject invention, and methods for producing the same. The subject fusion proteins find use in the preparation of a variety of nanostructures, where such structures include: cages, shells, double-layer rings, two-dimensional layers, three-dimensional crystals, filaments, and tubes.

  14. Low inductance connector assembly

    Science.gov (United States)

    Holbrook, Meghan Ann; Carlson, Douglas S

    2013-07-09

    A busbar connector assembly for coupling first and second terminals on a two-terminal device to first and second contacts on a power module is provided. The first terminal resides proximate the first contact and the second terminal resides proximate the second contact. The assembly comprises a first bridge having a first end configured to be electrically coupled to the first terminal, and a second end configured to be electrically coupled to the second contact, and a second bridge substantially overlapping the first bridge and having a first end electrically coupled to the first contact, and a second end electrically coupled to the second terminal.

  15. An Interactive Assembly Process Planner

    Institute of Scientific and Technical Information of China (English)

    廖华飞; 张林鍹; 肖田元; 曾理; 古月

    2004-01-01

    This paper describes the implementation and performance of the virtual assembly support system (VASS), a new system that can provide designers and assembly process engineers with a simulation and visualization environment where they can evaluate the assemblability/disassemblability of products, and thereby use a computer to intuitively create assembly plans and interactively generate assembly process charts. Subassembly planning and assembly priority reasoning techniques were utilized to find heuristic information to improve the efficiency of assembly process planning. Tool planning was implemented to consider tool requirements in the product design stage. New methods were developed to reduce the computation amount involved in interference checking. As an important feature of the VASS, human interaction was integrated into the whole process of assembly process planning, extending the power of computer reasoning by including human expertise, resulting in better assembly plans and better designs.

  16. Fire resistant PV shingle assembly

    Science.gov (United States)

    Lenox, Carl J.

    2012-10-02

    A fire resistant PV shingle assembly includes a PV assembly, including PV body, a fire shield and a connection member connecting the fire shield below the PV body, and a support and inter-engagement assembly. The support and inter-engagement assembly is mounted to the PV assembly and comprises a vertical support element, supporting the PV assembly above a support surface, an upper interlock element, positioned towards the upper PV edge, and a lower interlock element, positioned towards the lower PV edge. The upper interlock element of one PV shingle assembly is inter-engageable with the lower interlock element of an adjacent PV shingle assembly. In some embodiments the PV shingle assembly may comprise a ventilation path below the PV body. The PV body may be slidably mounted to the connection member to facilitate removal of the PV body.

  17. A Method for Designing Assembly Tolerance Networks of Mechanical Assemblies

    Directory of Open Access Journals (Sweden)

    Yi Zhang

    2012-01-01

    Full Text Available When designing mechanical assemblies, assembly tolerance design is an important issue which must be seriously considered by designers. Assembly tolerances reflect functional requirements of assembling, which can be used to control assembling qualities and production costs. This paper proposes a new method for designing assembly tolerance networks of mechanical assemblies. The method establishes the assembly structure tree model of an assembly based on its product structure tree model. On this basis, assembly information model and assembly relation model are set up based on polychromatic sets (PS theory. According to the two models, the systems of location relation equations and interference relation equations are established. Then, using methods of topologically related surfaces (TTRS theory and variational geometric constraints (VGC theory, three VGC reasoning matrices are constructed. According to corresponding relations between VGCs and assembly tolerance types, the reasoning matrices of tolerance types are also established by using contour matrices of PS. Finally, an exemplary product is used to construct its assembly tolerance networks and meanwhile to verify the feasibility and effectiveness of the proposed method.

  18. In-Ceram 全瓷冠与金属烤瓷冠对成纤维细胞株 L929细胞活力及相关基因表达的影响%Effect of In-Ceram all-ceramic crown and metal-ceramic crown on cell viabil ity and related gene expression in fibroblast cell l ines L929

    Institute of Scientific and Technical Information of China (English)

    石磊; 杨亮; 黄捷淳; 何恩宝; 吴志辉

    2016-01-01

    [ABSTRACT]Objective:To study the effect of In-Ceram all-ceramic crown and metal-ceramic crown on cell viability and related gene expression in fibroblast cell lines L929.Methods:Fibroblast cell lines L929 were cultured and treated with extract solution of In-Ceram all-ceramic crown,Ni-Cr alloy porcelain crown and Co-Cr alloy porcelain crown respectively,and then cell viability,serum cytokine contents as well as mRNA contents of Fas,FasL,Apo-1,mTOR and P70S6k in cells were detected. Results:Cell OD values of Ni-Cr alloy group and Co-Cr alloy group were significantly lower than that of negative control group;cell OD value of In-Ceram group was significantly higher than those of Ni-Cr alloy group and Co-Cr alloy group;TNF-α,IL-6 and IL-8 contents in cell culture medium of Ni-Cr alloy group and Co-Cr alloy group were significantly higher than those of neg-ative control group,and TNF-α,IL-6 and IL-8 contents in cell culture medium of In-Ceram group were significantly lower than those of Ni-Cr alloy group and Co-Cr alloy group and not different from those of negative control group;mRNA contents of Fas,FasL and Apo-1 in cells of Ni-Cr alloy group and Co-Cr alloy group were higher than those of negative control group,mR-NA contents of mTOR and P70S6k were lower than those of negative control group,mRNA contents of Fas,FasL and Apo-1 in cells of In-Ceram group were lower than those of Ni-Cr alloy group and Co-Cr alloy group and not different from those of negative control group,and mRNA contents of mTOR and P70S6k were higher than those of Ni-Cr alloy group and Co-Cr alloy group and not different from those of negative control group.Conclusion:In-Ceram all-ceramic crown has good histocompati-bility and will not affect cell viability as well as generation of inflammatory factors and expression of apoptosis and proliferation-related genes in fibroblast cell lines L929.%目的::研究 In-Ceram 全瓷冠与金属烤瓷冠对成纤维细胞株 L929细胞活力及相关

  19. Metaphase Spindle Assembly

    Directory of Open Access Journals (Sweden)

    Tarun M. Kapoor

    2017-02-01

    Full Text Available A microtubule-based bipolar spindle is required for error-free chromosome segregation during cell division. In this review I discuss the molecular mechanisms required for the assembly of this dynamic micrometer-scale structure in animal cells.

  20. Dump valve assembly

    Science.gov (United States)

    Owen, T.J.

    1984-01-01

    A dump valve assembly comprising a body having a bore defined by a tapered wall and a truncated spherical valve member adapted to seat along a spherical surface portion thereof against said tapered wall. Means are provided for pivoting said valve member between a closed position engagable with said tapered wall and an open position disengaged therefrom.

  1. Ordinary General Assembly

    CERN Multimedia

    Staff Association

    2010-01-01

    Tuesday 20 April at 10.00 Council Chamber, Bldg 503 In conformity with the Statutes of the Staff Association, an ordinary General Assembly is organized once a year (article IV.2.1). Agenda   Adoption of the Agenda Approval of the Draft Minutes of the Ordinary General Assembly of 12 May 2009 Presentation and approval of the Activity Report 2009 Presentation and approval of the Financial Report 2009 Presentation and approval of the Auditors Report 2009 Programme for 2010 Presentation et and approval of the draft budget and subscription rate 2010 Election of the Election Committee Election of the Board of Auditors Miscellaneous We remind members of article IV.3.4 in the Statutes of the Association which reads: “After having dealt with all the items on the agenda, the members may, with the consent of the Assembly, have other matters discussed, but decisions may be taken only on the items listed on the agenda. Nevertheless, the Assembly may require t...

  2. Ordinary General Assembly

    CERN Multimedia

    Staff Association

    2011-01-01

    Tuesday 12 April at 14.00 Council Chamber, Bldg 503 In conformity with the Statutes of the Staff Association, an ordinary General Assembly is organized once a year (article IV.2.1). Agenda   Adoption of the Agenda Approval of the Draft Minutes of the Ordinary General Assembly of 20 April 2010 Presentation and approval of the Activity Report 2010 Presentation and approval of the Financial Report 2010 Presentation and approval of the Auditors Report 2010 Programme for 2011 Presentation et and approval of the draft budget and subscription rate 2012 Election of the Election Committee Election of the Board of Auditors Miscellaneous We remind members of article IV.3.4 in the Statutes of the Association which reads: “After having dealt with all the items on the agenda, the members may, with the consent of the Assembly, have other matters discussed, but decisions may be taken only on the items listed on the agenda. Nevertheless, the Assembly ma...

  3. Ordinary General Assembly

    CERN Multimedia

    Staff Association

    2011-01-01

    Tuesday 12 April at 14.00 Council Chamber, Bldg 503 In conformity with the Statutes of the Staff Association, an ordinary General Assembly is organized once a year (article IV.2.1). Agenda   Adoption of the Agenda Approval of the Draft Minutes of the Ordinary General Assembly of 20 April 2010 Presentation and approval of the Activity Report 2010 Presentation and approval of the Financial Report 2010 Presentation and approval of the Auditors Report 2010 Programme for 2011 Presentation and approval of the draft budget and subscription rate 2012 Election of the Election Committee Election of the Board of Auditors Miscellaneous We remind members of article IV.3.4 in the Statutes of the Association which reads: “After having dealt with all the items on the agenda, the members may, with the consent of the Assembly, have other matters discussed, but decisions may be taken only on the items listed on the agenda. Nevertheless, the Assembly may r...

  4. Supramolecular Assemblies in Photosynthesis

    Science.gov (United States)

    Wrachtrup, J.; Tietz, C.; Jelezko, F.; Gerken, U.; Schuler, S.; Götze, B.; Volkmer, A.

    2002-10-01

    The photosynthetic apparatus contains a wealth of supramolecular assemblies that are optimized for charge and energy transfer. Various techniques have been applied to investigate these functions that rely on the electronic interaction among pigment molecules. In this contribution we will present single-molecule studies of pigment protein complexes. They reveal new information about electronic interactions between chlorophyll molecules in light harvesting complexes.

  5. Turbomachine blade assembly

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Crespo, Andres Jose

    2016-11-01

    Embodiments of the present disclosure include a system comprising a turbomachine blade assembly having a blade portion, a shank portion, and a mounting portion, wherein the blade portion, the shank portion, and the mounting portion comprise a first plurality of plies extending from a tip of the airfoil to a base of the dovetail.

  6. America's Assembly Line

    DEFF Research Database (Denmark)

    Nye, David Edwin

    A social history of the assembly line, invented in 1913. Both praised as a boon to consumers and as a curse for workers, it has been satirized, imitated, and celebrated for 100 years. It has inspired fiction, comedy, cafeteria layouts, and suburban housing. It transformed industrial labor...

  7. Industrial Assembly Cases

    DEFF Research Database (Denmark)

    Ellekilde, Lars-Peter; Buch, Jacob Pørksen; Iversen, Thorbjørn Mosekjær;

    This technical report presents 13 different industrial assembly tasks, which are composed of 70 different operations. The report is written to provide an overview and do as such not contain product specific information such as object weights, dimensions etc. The operations are classified into a set...

  8. Assembling Sustainable Territories

    DEFF Research Database (Denmark)

    Vandergeest, Peter; Ponte, Stefano; Bush, Simon

    2015-01-01

    that territorialisation is accomplished not just through (re)defining bounded space, but more broadly through the assembling of four elements: space, subjects, objects, and expertise. Four case studies of sustainability certification in seafood are analyzed to show that ‘green gabbing’ is not necessarily the central...

  9. Top-down assembly design using assembly features

    Institute of Scientific and Technical Information of China (English)

    石万凯; DENEUX; Dominique; 等

    2002-01-01

    The primary task of top-down assembly desig is to define a product's detailed physical description satisfying its functional requirements identified during the functional design phase.The implementation of this design process requires two things,that is ,product functional representation and a general assembly model.Product functions are not only the formulation of a customer's needs,but also the input data of assembly design.A general assembly model is to support the evolving process of the elaboration of a product structure.The assembly feature of extended concept is taken as a functional carrier,which is a generic relation among assembly-modeled entities.The model of assembly features describes the link between product functions and form features of parts.On the basis of this link,the propagation of design modifications is discussed so as to preserve the functionality and the coherence of the assembly model.The formal model of assembly design process describes the top-down process of creating an assembly model.This formal model is represented by the combination of assembly feature operations,the assembly model and the evaluation process.A design case study is conducted to verify the applicability of the presented approaches.

  10. Optical Space Telescope Assembly Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Optical Space Telescope Assembly (OSTA) task is to demonstrate the technology readiness of assembling large space telescopes on orbit in 2015. This task is an...

  11. X-Ray Assembler Data

    Data.gov (United States)

    U.S. Department of Health & Human Services — Federal regulations require that an assembler who installs one or more certified components of a diagnostic x-ray system submit a report of assembly. This database...

  12. Low inductance busbar assembly

    Science.gov (United States)

    Holbrook, Meghan Ann

    2010-09-21

    A busbar assembly for electrically coupling first and second busbars to first and second contacts, respectively, on a power module is provided. The assembly comprises a first terminal integrally formed with the first busbar, a second terminal integrally formed with the second busbar and overlapping the first terminal, a first bridge electrode having a first tab electrically coupled to the first terminal and overlapping the first and second terminals, and a second tab electrically coupled to the first contact, a second bridge electrode having a third tab electrically coupled to the second terminal, and overlapping the first and second terminals and the first tab, and a fourth tab electrically coupled to the second contact, and a fastener configured to couple the first tab to the first terminal, and the third tab to the second terminal.

  13. Fourth Doctoral Student Assembly

    CERN Multimedia

    Ingrid Haug

    2016-01-01

    On 10 May, over 130 PhD students and their supervisors, from both CERN and partner universities, gathered for the 4th Doctoral Student Assembly in the Council Chamber.   The assembly was followed by a poster session, at which eighteen doctoral students presented the outcome of their scientific work. The CERN Doctoral Student Programme currently hosts just over 200 students in applied physics, engineering, computing and science communication/education. The programme has been in place since 1985. It enables students to do their research at CERN for a maximum of three years and to work on a PhD thesis, which they defend at their University. The programme is steered by the TSC committee, which holds two selection committees per year, in June and December. The Doctoral Student Assembly was opened by the Director-General, Fabiola Gianotti, who stressed the importance of the programme in the scientific environment at CERN, emphasising that there is no more rewarding activity than lear...

  14. OH Module Assembly Stand

    Energy Technology Data Exchange (ETDEWEB)

    Bolan, P.J.; /Fermilab

    1990-10-16

    There is an OR module assembly stand in use at IB4. This design has been approved by safety, as presented by Mike Foley, and has been successfully used. Another one is needed at the D-zero assembly building, but some modifications need to be made. This report will show that the new modified design is at least as strong, if not stronger, than the older IB4 design in every aspect. Since the weight distribution of the OR modules on the sling is indeterminate, this report compares three cases of support for the entire assembly: the lowest two beams only, the lowest four beams only, and all six beams. In each of these cases, the new design is stronger than the old design in maximum allowable weight. The ability of the the cradle to support the weight is also shown. For all of the failure conditions except for two, the cradle is stronger than the beams that it supports. In the two excepted situations, the calculated limit of the cradle is less than the beams it supports. This is because no credit is taken for the sling and strongback, which in reality will relieve much of the horizontal load.

  15. IAHS Third Scientific Assembly

    Science.gov (United States)

    The International Association of Hydrological Sciences (IAHS) convened its Third Scientific Assembly in Baltimore, Md., May 10-19, 1989. The Assembly was attended by about 450 scientists and engineers. The attendance was highest from the U.S., as could be expected; 37 were from Canada; 22 each, Netherlands and United Kingdom; 14, Italy; 12, China; 10, Federal Republic of Germany; 8 each from France, the Republic of South Africa, and Switzerland; 7, Austria; 6 each, Finland and Japan; others were scattered among the remainder of 48 countries total.one of the cosponsors and also handled business matters for the Assembly. Other cosponsors included the International Association of Meteorology and Atmospheric Physics (IAMAP), United Nations Environmental Program (UNEP), United Nations Educational, Scientific, and Cultural Organization (UNESCO), World Meteorological Organization (WMO), and U.K. Overseas Development Authority (ODA). U.S. federal agencies serving as cosponsors included the Environmental Protection Agency, National Aeronautics and Space Administration, National Science Foundation, National Weather Service, Department of Agriculture, Department of State, and U.S. Geological Survey.

  16. Ordinary General Assembly

    CERN Multimedia

    Association du personnel

    2010-01-01

    Tuesday 20 April at 10.00 Council Chamber, Bldg 503 In conformity with the Statutes of the Staff Association, an ordinary General Assembly is organized once a year (article IV.2.1). Agenda Adoption of the Agenda Approval of the Draft Minutes of the Ordinary General Assembly of 12 May 2009 Presentation and approval of the Activity Report 2009 Presentation and approval of the Financial Report 2009 Presentation and approval of the Auditors Report 2009 Programme for 2010 Presentation et and approval of the draft budget and subscription rate 2010 Modifications to the statutes of the association Election of the Election Committee Election of the Board of Auditors Miscellaneous We remind members of article IV.3.4 in the Statutes of the Association which reads: “After having dealt with all the items on the agenda, the members may, with the consent of the Assembly, have other matters discussed, but decisions may be taken only on the items listed on the agenda...

  17. SCT Barrel Assembly Complete

    CERN Multimedia

    L. Batchelor

    As reported in the April 2005 issue of the ATLAS eNews, the first of the four Semiconductor Tracker (SCT) barrels, complete with modules and services, arrived safely at CERN in January of 2005. In the months since January, the other three completed barrels arrived as well, and integration of the four barrels into the entire barrel assembly commenced at CERN, in the SR1 building on the ATLAS experimental site, in July. Assembly was completed on schedule in September, with the addition of the innermost layer to the 4-barrel assembly. Work is now underway to seal the barrel thermal enclosure. This is necessary in order to enclose the silicon tracker in a nitrogen atmosphere and provide it with faraday-cage protection, and is a delicate and complicated task: 352 silicon module powertapes, 352 readout-fibre bundles, and over 400 Detector Control System sensors must be carefully sealed into the thermal enclosure bulkhead. The team is currently verifying the integrity of the low mass cooling system, which must be d...

  18. Spatially confined assembly of nanoparticles.

    Science.gov (United States)

    Jiang, Lin; Chen, Xiaodong; Lu, Nan; Chi, Lifeng

    2014-10-21

    The ability to assemble NPs into ordered structures that are expected to yield collective physical or chemical properties has afforded new and exciting opportunities in the field of nanotechnology. Among the various configurations of nanoparticle assemblies, two-dimensional (2D) NP patterns and one-dimensional (1D) NP arrays on surfaces are regarded as the ideal assembly configurations for many technological devices, for example, solar cells, magnetic memory, switching devices, and sensing devices, due to their unique transport phenomena and the cooperative properties of NPs in assemblies. To realize the potential applications of NP assemblies, especially in nanodevice-related applications, certain key issues must still be resolved, for example, ordering and alignment, manipulating and positioning in nanodevices, and multicomponent or hierarchical structures of NP assemblies for device integration. Additionally, the assembly of NPs with high precision and high levels of integration and uniformity for devices with scaled-down dimensions has become a key and challenging issue. Two-dimensional NP patterns and 1D NP arrays are obtained using traditional lithography techniques (top-down strategies) or interfacial assembly techniques (bottom-up strategies). However, a formidable challenge that persists is the controllable assembly of NPs in desired locations over large areas with high precision and high levels of integration. The difficulty of this assembly is due to the low efficiency of small features over large areas in lithography techniques or the inevitable structural defects that occur during the assembly process. The combination of self-assembly strategies with existing nanofabrication techniques could potentially provide effective and distinctive solutions for fabricating NPs with precise position control and high resolution. Furthermore, the synergistic combination of spatially mediated interactions between nanoparticles and prestructures on surfaces may play

  19. Multivalent Protein Assembly Using Monovalent Self-Assembling Building Blocks

    Directory of Open Access Journals (Sweden)

    Katja Petkau-Milroy

    2013-10-01

    Full Text Available Discotic molecules, which self-assemble in water into columnar supramolecular polymers, emerged as an alternative platform for the organization of proteins. Here, a monovalent discotic decorated with one single biotin was synthesized to study the self-assembling multivalency of this system in regard to streptavidin. Next to tetravalent streptavidin, monovalent streptavidin was used to study the protein assembly along the supramolecular polymer in detail without the interference of cross-linking. Upon self-assembly of the monovalent biotinylated discotics, multivalent proteins can be assembled along the supramolecular polymer. The concentration of discotics, which influences the length of the final polymers at the same time dictates the amount of assembled proteins.

  20. Failure of granular assemblies

    OpenAIRE

    Welker, Philipp

    2011-01-01

    This work investigates granular assemblies subjected to increasing external forces in the quasi-static limit. In this limit, the system’s evolution depends on static properties of the system, but is independent of the particles’ inertia. At the failure, which occurs at a certain value of the external forces, the particles’ motions increase quickly. In this thesis, the properties of granular systems during the weakening process and at the failure are investigated with the Discrete Element Meth...

  1. On Constraints in Assembly Planning

    Energy Technology Data Exchange (ETDEWEB)

    Calton, T.L.; Jones, R.E.; Wilson, R.H.

    1998-12-17

    Constraints on assembly plans vary depending on product, assembly facility, assembly volume, and many other factors. Assembly costs and other measures to optimize vary just as widely. To be effective, computer-aided assembly planning systems must allow users to express the plan selection criteria that appIy to their products and production environments. We begin this article by surveying the types of user criteria, both constraints and quality measures, that have been accepted by assembly planning systems to date. The survey is organized along several dimensions, including strategic vs. tactical criteria; manufacturing requirements VS. requirements of the automated planning process itself and the information needed to assess compliance with each criterion. The latter strongly influences the efficiency of planning. We then focus on constraints. We describe a framework to support a wide variety of user constraints for intuitive and efficient assembly planning. Our framework expresses all constraints on a sequencing level, specifying orders and conditions on part mating operations in a number of ways. Constraints are implemented as simple procedures that either accept or reject assembly operations proposed by the planner. For efficiency, some constraints are supplemented with special-purpose modifications to the planner's algorithms. Fast replanning enables an interactive plan-view-constrain-replan cycle that aids in constraint discovery and documentation. We describe an implementation of the framework in a computer-aided assembly planning system and experiments applying the system to a number of complex assemblies, including one with 472 parts.

  2. Hollow fiber apparatus and use thereof for fluids separations and heat and mass transfers

    Science.gov (United States)

    Bikson, Benjamin; Etter, Stephen; Ching, Nathaniel

    2014-06-10

    A hollow fiber device includes a hollow fiber bundle, comprising a plurality of hollow fibers, a first tubesheet and a second tubesheet encapsulating respective distal ends of the hollow fiber bundle. The tubesheets have boreholes in fluid communication with bores of the hollow fibers. In at least one of the tubesheets, the boreholes are formed radially. The hollow fiber device can be utilized in heat exchange, in gas/gas, liquid/liquid and gas/liquid heat transfer, in combined heat and mass transfer and in fluid separation assemblies and processes. The design disclosed herein is light weight and compact and is particularly advantageous when the pressure of a first fluid introduced into the bores of hollow fibers is higher than the pressure on the shell side of the device.

  3. Progress of EMBarrel assembly

    CERN Multimedia

    Chalifour, M

    2002-01-01

    The assembly of the sixteen "M" modules into a vertical axis cylinder has been achieved last Friday, completing the first wheel of the Electromagnetic Barrel Calorimeter (see picture). With this, an important milestone in the construction of the ATLAS detector has been reached. Future steps are the rotation of the cylinder axis into horizontal position, in order to integrate the presamplers and heat exchangers by the end of October. The transportation of the wheel and its insertion into the cryostat is the next major milestone, and is planned for the beginning of 2003. The construction of the modules (the so-called "P" modules) of the second wheel is ongoing at Saclay, Annecy and CERN, and will be completed in the coming months. The assembly of the second wheel should start at CERN in February, and its insertion in the cryostat is scheduled for June 2003. This achievement is the result of a successful collaboration of all institutes involved in the construction of the EM Barrel, namely Annecy, Saclay and CE...

  4. Microchannel heat sink assembly

    Science.gov (United States)

    Bonde, Wayne L.; Contolini, Robert J.

    1992-01-01

    The present invention provides a microchannel heat sink with a thermal range from cryogenic temperatures to several hundred degrees centigrade. The heat sink can be used with a variety of fluids, such as cryogenic or corrosive fluids, and can be operated at a high pressure. The heat sink comprises a microchannel layer preferably formed of silicon, and a manifold layer preferably formed of glass. The manifold layer comprises an inlet groove and outlet groove which define an inlet manifold and an outlet manifold. The inlet manifold delivers coolant to the inlet section of the microchannels, and the outlet manifold receives coolant from the outlet section of the microchannels. In one embodiment, the manifold layer comprises an inlet hole extending through the manifold layer to the inlet manifold, and an outlet hole extending through the manifold layer to the outlet manifold. Coolant is supplied to the heat sink through a conduit assembly connected to the heat sink. A resilient seal, such as a gasket or an O-ring, is disposed between the conduit and the hole in the heat sink in order to provide a watetight seal. In other embodiments, the conduit assembly may comprise a metal tube which is connected to the heat sink by a soft solder. In still other embodiments, the heat sink may comprise inlet and outlet nipples. The present invention has application in supercomputers, integrated circuits and other electronic devices, and is suitable for cooling materials to superconducting temperatures.

  5. ULTRASONIC ASSEMBLY [REVIEW

    Directory of Open Access Journals (Sweden)

    PORAV Viorica

    2015-05-01

    Full Text Available The paper exposes the possibility of machine producesers to optimize the costs of clothes assembling. Ultrasonic systems being frequently utilized have many advantages on semi products of synthetic textile and technical textile. First of all, sewing – cutting process can be accomplished under high speeds and rate of losses can be minimized. Cutting seal applications are frequently used for underwear and sportswear. Slicing and unit cutting machines, as well as portable sealing machines are available for labeling sector. Products such as bag, pocket and cover can be sewed in a seamless manner for promotion purposes. All objects in terms of accessories are obtained in same standard. Our quilting machines are preferred in worldwide due to its threadless, high quality sealing. An alternative to the classic sewing assembly, with thread and needles is ultrasonic seaming. In ultrasonic welding, there are no connective bolts, nails, soldering materials, or adhesives necessary to bind the materials together. Ultrasonic is defined as acoustic frequencies above the range audible to the human ear. Ultrasonic frequencies are administered to the fabric from the sonotrode of bonding machine. The high frequency and powerful energy produced, when is release in one special environment, the ultrasound heating this environment. The ability to ultrasonic weld textiles and films depend on their thermoplastic contents and the desired end results. The paper defines the weld ability of more common textiles and films. The welding refers to all types of bonding and sealing, as in point bonding of fabric, or continuous sealing of film.

  6. ANNUAL GENERAL ASSEMBLY

    CERN Multimedia

    2001-01-01

    All members and beneficiaries of the Pension Fund are invited to attend the Annual General Asssembly to be held in the CERN Auditorium on Wednesday 3 October 2001 at 14.30 hrs The Agenda comprises:   Opening Remarks (P. Levaux) Some aspects of risk in a pension fund (C. Cuénoud) Annual Report 2000: Presentation and results (C. Cuénoud) Copies of the Report are available from divisional secretariats. Results of the actuarial reviews (G. Maurin) Questions from members and beneficiaries Persons wishing to ask questions are encouraged to submit them, where possible, in writing in advance, addressed to Mr C. Cuénoud, Administrator of the Fund. Conclusions (P. Levaux) As usual, participants are invited to drinks after the assembly. NB The minutes of the 2000 General Assembly are available from the Administration of the Fund (tel. + 41 22 767 91 94; e-mail Graziella.Praire@cern.ch) The English version will be published next week.

  7. Selecting Operations for Assembler Encoding

    Directory of Open Access Journals (Sweden)

    Tomasz Praczyk

    2010-04-01

    Full Text Available Assembler Encoding is a neuro-evolutionary method in which a neural network is represented in the form of a simple program called Assembler Encoding Program. The task of the program is to create the so-called Network Definition Matrix which maintains all the information necessary to construct the network. To generate Assembler Encoding Programs and the subsequent neural networks evolutionary techniques are used.
    The performance of Assembler Encoding strongly depends on operations used in Assembler Encoding Programs. To select the most effective operations, experiments in the optimization and the predator-prey problem were carried out. In the experiments, Assembler Encoding Programs equipped with different types of operations were tested. The results of the tests are presented at the end of the paper.

  8. Coded nanoscale self-assembly

    Indian Academy of Sciences (India)

    Prathyush Samineni; Debabrata Goswami

    2008-12-01

    We demonstrate coded self-assembly in nanostructures using the code seeded at the component level through computer simulations. Defects or cavities occur in all natural assembly processes including crystallization and our simulations capture this essential aspect under surface minimization constraints for self-assembly. Our bottom-up approach to nanostructures would provide a new dimension towards nanofabrication and better understanding of defects and crystallization process.

  9. Next-generation transcriptome assembly

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Jeffrey A.; Wang, Zhong

    2011-09-01

    Transcriptomics studies often rely on partial reference transcriptomes that fail to capture the full catalog of transcripts and their variations. Recent advances in sequencing technologies and assembly algorithms have facilitated the reconstruction of the entire transcriptome by deep RNA sequencing (RNA-seq), even without a reference genome. However, transcriptome assembly from billions of RNA-seq reads, which are often very short, poses a significant informatics challenge. This Review summarizes the recent developments in transcriptome assembly approaches - reference-based, de novo and combined strategies-along with some perspectives on transcriptome assembly in the near future.

  10. Rocket Assembly and Checkout Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Integrates, tests, and calibrates scientific instruments flown on sounding rocket payloads. The scientific instruments are assembled on an optical bench;...

  11. Geometric reasoning about assembly tools

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, R.H.

    1997-01-01

    Planning for assembly requires reasoning about various tools used by humans, robots, or other automation to manipulate, attach, and test parts and subassemblies. This paper presents a general framework to represent and reason about geometric accessibility issues for a wide variety of such assembly tools. Central to the framework is a use volume encoding a minimum space that must be free in an assembly state to apply a given tool, and placement constraints on where that volume must be placed relative to the parts on which the tool acts. Determining whether a tool can be applied in a given assembly state is then reduced to an instance of the FINDPLACE problem. In addition, the author presents more efficient methods to integrate the framework into assembly planning. For tools that are applied either before or after their target parts are mated, one method pre-processes a single tool application for all possible states of assembly of a product in polynomial time, reducing all later state-tool queries to evaluations of a simple expression. For tools applied after their target parts are mated, a complementary method guarantees polynomial-time assembly planning. The author presents a wide variety of tools that can be described adequately using the approach, and surveys tool catalogs to determine coverage of standard tools. Finally, the author describes an implementation of the approach in an assembly planning system and experiments with a library of over one hundred manual and robotic tools and several complex assemblies.

  12. Moisture Research - Optimizing Wall Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Arena, Lois [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States); Mantha, Pallavi [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States)

    2013-05-01

    In this project, the Consortium for Advanced Residential Buildings (CARB) team evaluated several different configurations of wall assemblies to determine the accuracy of moisture modeling and make recommendations to ensure durable, efficient assemblies. WUFI and THERM were used to model the hygrothermal and heat transfer characteristics of these walls. Wall assemblies evaluated included code minimum walls using spray foam insulation and fiberglass batts, high R-value walls at least 12 in. thick (R-40 and R-60 assemblies), and brick walls with interior insulation.

  13. Seismic behaviour of fuel assembly

    Energy Technology Data Exchange (ETDEWEB)

    Song, Heuy Gap; Jhung, Myung Jo [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1993-11-01

    A general approach for the dynamic time-history analysis of the reactor core is presented in this paper as a part of the fuel assembly qualification program. Several detailed core models are set up to reflect the placement of the fuel assemblies within the core shroud. Peak horizontal responses are obtained for each model for the motions induced from earthquake. The dynamic responses such as fuel assembly shear force, bending moment and displacement, and spacer grid impact loads are carefully investigated. Also, the sensitivity responses are obtained for the earthquake motions and the fuel assembly non-linear response characteristics are discussed. (Author) 9 refs., 24 figs., 1 tab.

  14. Multi-position photovoltaic assembly

    Science.gov (United States)

    Dinwoodie, Thomas L.

    2003-03-18

    The invention is directed to a PV assembly, for use on a support surface, comprising a base, a PV module, a multi-position module support assembly, securing the module to the base at shipping and inclined-use angles, a deflector, a multi-position deflector support securing the deflector to the base at deflector shipping and deflector inclined-use angles, the module and deflector having opposed edges defining a gap therebetween. The invention permits transport of the PV assemblies in a relatively compact form, thus lowering shipping costs, while facilitating installation of the PV assemblies with the PV module at the proper inclination.

  15. Cilium assembly and disassembly

    Science.gov (United States)

    2016-01-01

    The primary cilium is an antenna-like, immotile organelle present on most types of mammalian cells, which interprets extracellular signals that regulate growth and development. Although once considered a vestigial organelle, the primary cilium is now the focus of considerable interest. We now know that ciliary defects lead to a panoply of human diseases, termed ciliopathies, and the loss of this organelle may be an early signature event during oncogenic transformation. Ciliopathies include numerous seemingly unrelated developmental syndromes, with involvement of the retina, kidney, liver, pancreas, skeletal system and brain. Recent studies have begun to clarify the key mechanisms that link cilium assembly and disassembly to the cell cycle, and suggest new possibilities for therapeutic intervention. PMID:27350441

  16. Photovoltaic cell assembly

    Science.gov (United States)

    Beavis, Leonard C.; Panitz, Janda K. G.; Sharp, Donald J.

    1990-01-01

    A photovoltaic assembly for converting high intensity solar radiation into lectrical energy in which a solar cell is separated from a heat sink by a thin layer of a composite material which has excellent dielectric properties and good thermal conductivity. This composite material is a thin film of porous Al.sub.2 O.sub.3 in which the pores have been substantially filled with an electrophoretically-deposited layer of a styrene-acrylate resin. This composite provides electrical breakdown strengths greater than that of a layer consisting essentially of Al.sub.2 O.sub.3 and has a higher thermal conductivity than a layer of styrene-acrylate alone.

  17. Fluid cooled electrical assembly

    Science.gov (United States)

    Rinehart, Lawrence E.; Romero, Guillermo L.

    2007-02-06

    A heat producing, fluid cooled assembly that includes a housing made of liquid-impermeable material, which defines a fluid inlet and a fluid outlet and an opening. Also included is an electrical package having a set of semiconductor electrical devices supported on a substrate and the second major surface is a heat sink adapted to express heat generated from the electrical apparatus and wherein the second major surface defines a rim that is fit to the opening. Further, the housing is constructed so that as fluid travels from the fluid inlet to the fluid outlet it is constrained to flow past the opening thereby placing the fluid in contact with the heat sink.

  18. Newnes electronics assembly pocket book

    CERN Document Server

    Brindley, Keith

    2013-01-01

    Produced in association with the Engineering Training Authority with contributions from dozens of people in the electronics industry. The material covers common skills in electrical and electronic engineering and concentrates mainly on wiring and assembly. 'Newnes Electronics Assembly Pocket Book' is for electronics technicians, students and apprentices.

  19. The Bicycle Assembly Line Game

    Science.gov (United States)

    Klotz, Dorothy

    2011-01-01

    "The Bicycle Assembly Line Game" is a team-based, in-class activity that helps students develop a basic understanding of continuously operating processes. Each team of 7-10 students selects one of seven prefigured bicycle assembly lines to operate. The lines are run in real-time, and the team that operates the line that yields the…

  20. Assembly sequencing with toleranced parts

    Energy Technology Data Exchange (ETDEWEB)

    Latombe, J.C. [Stanford Univ., CA (United States). Robotics Lab.; Wilson, R.H. [Sandia National Labs., Albuquerque, NM (United States). Intelligent Systems and Robotics Center

    1995-02-21

    The goal of assembly sequencing is to plan a feasible series of operations to construct a product from its individual parts. Previous research has thoroughly investigated assembly sequencing under the assumption that parts have nominal geometry. This paper considers the case where parts have toleranced geometry. Its main contribution is an efficient procedure that decides if a product admits an assembly sequence with infinite translations that is feasible for all possible instances of the components within the specified tolerances. If the product admits one such sequence, the procedure can also generate it. For the cases where there exists no such assembly sequence, another procedure is proposed which generates assembly sequences that are feasible only for some values of the toleranced dimensions. If this procedure produces no such sequence, then no instance of the product is assemblable. Finally, this paper analyzes the relation between assembly and disassembly sequences in the presence of toleranced parts. This work assumes a simple, but non-trivial tolerance language that falls short of capturing all imperfections of a manufacturing process. Hence, it is only one step toward assembly sequencing with toleranced parts.

  1. Integrating genome assemblies with MAIA

    NARCIS (Netherlands)

    Nijkamp, J.F.; Winterbach, W.; Van den Broek, M.; Daran, J.M.; Reinders, M.J.T.; De Ridder, D.

    2010-01-01

    De novo assembly of a eukaryotic genome with next-generation sequencing data is still a challenging task. Over the past few years several assemblers have been developed, often suitable for one specific type of sequencing data. The number of known genomes is expanding rapidly, therefore it becomes po

  2. Fuel cell sub-assembly

    Science.gov (United States)

    Chi, Chang V.

    1983-01-01

    A fuel cell sub-assembly comprising a plurality of fuel cells, a first section of a cooling means disposed at an end of the assembly and means for connecting the fuel cells and first section together to form a unitary structure.

  3. Moisture Research - Optimizing Wall Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Arena, L.; Mantha, P.

    2013-05-01

    The Consortium for Advanced Residential Buildings (CARB) evaluated several different configurations of wall assemblies to determine the accuracy of moisture modeling and make recommendations to ensure durable, efficient assemblies. WUFI and THERM were used to model the hygrothermal and heat transfer characteristics of these walls.

  4. ASSEMBLY TRANSFER SYSTEM DESCRIPTION DOCUMENT

    Energy Technology Data Exchange (ETDEWEB)

    B. Gorpani

    2000-06-26

    The Assembly Transfer System (ATS) receives, cools, and opens rail and truck transportation casks from the Carrier/Cask Handling System (CCHS). The system unloads transportation casks consisting of bare Spent Nuclear Fuel (SNF) assemblies, single element canisters, and Dual Purpose Canisters (DPCs). For casks containing DPCs, the system opens the DPCs and unloads the SNF. The system stages the assemblies, transfer assemblies to and from fuel-blending inventory pools, loads them into Disposal Containers (DCs), temporarily seals and inerts the DC, decontaminates the DC and transfers it to the Disposal Container Handling System. The system also prepares empty casks and DPCs for off-site shipment. Two identical Assembly Transfer System lines are provided in the Waste Handling Building (WHB). Each line operates independently to handle the waste transfer throughput and to support maintenance operations. Each system line primarily consists of wet and dry handling areas. The wet handling area includes a cask transport system, cask and DPC preparation system, and a wet assembly handling system. The basket transport system forms the transition between the wet and dry handling areas. The dry handling area includes the dry assembly handling system, assembly drying system, DC preparation system, and DC transport system. Both the wet and dry handling areas are controlled by the control and tracking system. The system operating sequence begins with moving transportation casks to the cask preparation area. The cask preparation operations consist of cask cavity gas sampling, cask venting, cask cool-down, outer lid removal, and inner shield plug lifting fixture attachment. Casks containing bare SNF (no DPC) are filled with water and placed in the cask unloading pool. The inner shield plugs are removed underwater. For casks containing a DPC, the cask lid(s) is removed, and the DPC is penetrated, sampled, vented, and cooled. A DPC lifting fixture is attached and the cask is placed

  5. Tile Calorimete Pre-Assembly Summary and Barrel Assembly Plan

    CERN Document Server

    Proudfoot, J; Liablin, M V; Topilin, N D

    2004-01-01

    The barrel survey results from the pre-assembly in Building 185 are reviewed. From these and the models developed to calculate the cylinder geometry we propose a minimal modification to the shimming plan for the barrel calorimeter assembly in the Atlas cavern. At the precision of this calculation, we expect the tile calorimeter to be almost entirely within it design envelope. The focus of this note is the radial envelope. Based on the pre-assembly experience the tile calorimeter will fit comfortably within its envelope along the beam line.

  6. Subcritical nuclear assembly

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R., E-mail: fermineutron@yahoo.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2014-08-15

    A Subcritical Nuclear Assembly is a device where the nuclear-fission chain reaction is initiated and maintained using an external neutron source. It is a valuable educational and research tool where in a safe way many reactor parameters can be measured. Here, we have used the Wigner-Seitz method in the six-factor formula to calculate the effective multiplication factor of a subcritical nuclear reactor Nuclear Chicago model 9000. This reactor has approximately 2500 kg of natural uranium heterogeneously distributed in slugs. The reactor uses a {sup 239}PuBe neutron source that is located in the center of an hexagonal array. Using Monte Carlo methods, with the MCNP5 code, a three-dimensional model of the subcritical reactor was designed to estimate the effective multiplication factor, the neutron spectra, the total and thermal neutron fluences along the radial and axial axis. With the neutron spectra in two locations outside the reactor the ambient dose equivalent were estimated. (Author)

  7. Conservative restorative treatment using a single-visit, all-ceramic CAD/CAM system.

    Science.gov (United States)

    Benk, Joel

    2007-01-01

    Computer-aided design/computer-aided manufacturing (CAD/CAM) continues to radically change the way in which the dental team plans, prepares, and fabricates a patient's restoration. This advancing technology offers the clinician the ability to scan the patient's failing dentition and then designs a long-lasting, reliable restoration based on this data. CAD/CAM systems also permit efficient, single-visit placement of the restoration while preserving much of the natural tooth structure. This article discusses how a chairside CAD/CAM system can be used to provide such a restoration in the posterior region in a single-visit.

  8. Internal fit of two all-ceramic systems and metal-ceramic crowns

    OpenAIRE

    Leandro Moura Martins; Fabio Cesar Lorenzoni; Alcides Oliveira de Melo; Luciana Mendonça da Silva; José Luiz G. de Oliveira; Pedro Cesar Garcia de Oliveira; Gerson Bonfante

    2012-01-01

    Objectives: The aim of this study was to investigate the internal fit (IF) of glass-infiltrated alumina (ICA - In-Ceram Alumina), yttria-stabilized tetragonal zirconia polycrystals (Y-TZP - IPS e.max ZirCAD), and metal-ceramic (MC - Ni-Cr alloy) crowns. Material and Methods: Sixty standardized resin-tooth replicas of a maxillary first molar were produced for crown placement and divided into 3 groups (n=20 each) according to the core material used (metal, ICA or Y-TZP). The IF of the crowns wa...

  9. Degree of Conversion and Mechanical Properties of Resin Cements Cured Through Different All-Ceramic Systems

    OpenAIRE

    Lopes, Camila de Carvalho Almança; Rodrigues, Renata Borges; André Luis Faria e Silva; Paulo Cézar SIMAMOTO JÚNIOR; Soares, Carlos José; Novais,Veridiana Resende

    2015-01-01

    Abstract: The aim of this study was to verify the degree of conversion (DC), Vickers microhardness (VH) and elastic modulus (E) of resin cements cured through different ceramic systems. One 1.5-mm-thick disc of each ceramic system (feldspathic, lithium dissilicate and zircônia veneered with feldspathic) was used. Three dual-cured (Allcem, Variolink II and RelyX U200) and one chemically-cured (Multilink) resin cements were activated through ceramic discs. For dual-cured resin cements was used ...

  10. Influence of Interlayer Design on Residual Thermal Stresses in Trilayered and Graded All-Ceramic Restorations

    Science.gov (United States)

    Henriques, Bruno; Fabris, Douglas; Souza, Júlio C. M.; Silva, Filipe S.; Mesquita-Guimarães, Joana; Zhang, Yu; Fredel, Márcio

    2017-01-01

    Residual thermal stresses are formed in dental restorations during cooling from high temperature processing. The aim of this study was to evaluate the influence of constructive design variables (composition and interlayer thickness) on residual stresses in alumina- and zirconia-graded restorations. Restorations' real-like cooling conditions were simulated using finite elements method and temperature-dependent material properties were used. Three different designs were evaluated: a bilayered restoration (sharp transition between materials); a trilayered restoration with a homogenous interlayer between core and veneer; and a trilayered restoration with a graded interlayer. The interlayer thickness and composition were varied. Zirconia restorations presented overall higher thermal stress values than alumina ones. Thermal stresses were significantly reduced by the presence of a homogeneous interlayer. The composition of the interlayer showed great influence on the thermal stresses, with the best results for homogeneous interlayers being observed for porcelain contents in the composite ranging between 30%-50% (vol.%), for both alumina and zirconia restorations. The interlayer's thickness showed a minor contribution in the thermal stress reduction. The graded interlayer showed an optimized reduction in restorations' thermal stresses. The use of graded interlayer, favoring enhanced thermal stress distributions and lower magnitude is expected to reduce the risk of catastrophic failure. PMID:27987657

  11. Effect of etchant variability on shear bond strength of all ceramic restorations - an in vitro study

    OpenAIRE

    Pattanaik, Seema; Wadkar, Aarti P.

    2011-01-01

    The present study was carried out to evaluate the effect of pre-luting surface treatments by 3 different etchant used at 3 different etching periods and their effect on shear bond strength of IPS Empress 2 luted to tooth by dual cure resin cement. Fifty samples of ceramic were divided into four groups as group I control group: No surface treatment, group II: Etched with Hydrofluoric (HF) acid (4.9%), group III: Etched with Ammonium bifluoride acid (9.4%) and group IV: Etched with Phosphoric a...

  12. Effect of etchant variability on shear bond strength of all ceramic restorations - an in vitro study.

    Science.gov (United States)

    Pattanaik, Seema; Wadkar, Aarti P

    2011-03-01

    The present study was carried out to evaluate the effect of pre-luting surface treatments by 3 different etchant used at 3 different etching periods and their effect on shear bond strength of IPS Empress 2 luted to tooth by dual cure resin cement. Fifty samples of ceramic were divided into four groups as group I control group: No surface treatment, group II: Etched with Hydrofluoric (HF) acid (4.9%), group III: Etched with Ammonium bifluoride acid (9.4%) and group IV: Etched with Phosphoric acid (37%). Group II, III and IV were further divided into 3 Subgroups; namely A, B and C according to the etching periods (20, 60 and 120 s) respectively. The shear bond strength was determined by using a Universal testing Machine. The morphological changes of the surface treated ceramic samples prior to luting to tooth and mode of the fracture failure after shear bond test were observed by using a Scanning Electron Microscope. The mean shear bond strength was highest when IPS Empress 2 ceramic samples were surface treated using 4.9% Hydrofluoric acid gel and 9.4% Ammonium bifluoride acid for 120 s. The least mean shear bond strength was noticed in case of control group, where no surface treatment was done and samples treated by 37% Phosphoric acid. Thus it could be concluded, that Ammonium bifluoride could be an appropriate alternative to be used instead of HF acid. 120 s etching showed highest bond strength values for HF acid (4.9%) and Ammonium bifluoride (9.4%).

  13. Techniques used to fabricate all-ceramic restorations in the dental practice.

    Science.gov (United States)

    Puri, Sameer

    2005-07-01

    Porcelain is an increasingly popular material to use for restorations. This article will discuss the 3 main ways to fabricate porcelain restorations. The first method involves waxing up the restoration to the proper form and casting it in molten porcelain similar to the lost wax technique for gold. The second technique requires the use of porcelain in a powder form to be stacked on top of a refractory die or a platinum foil and then fired in the oven. The third main technique is the use of a CAD/CAM system to mill the porcelain restoration from a solid block of porcelain. All 3 techniques are valid and the clinician should have a thorough understanding of which techniques are appropriate in various clinical situations.

  14. Personal Factors Determining Patient Satisfaction with All-Ceramic Crown Treatment for Single Anterior Teeth.

    Science.gov (United States)

    Zou, Yun; Zhan, DeSong

    2016-01-01

    The Eysenck Personality Questionnaire's (EPQ) N value (neuroticism) was used to evaluate information from 158 patients before ceramic crown treatment. Patient satisfaction was also evaluated using a satisfaction questionnaire 2 weeks post treatment. Patient expectations were not correlated with sex, age, or N value, and sex was not correlated with patient satisfaction other than in relation to crown shape. Total esthetic satisfaction and feature improvement were positively correlated with age, while satisfaction for five specific criteria was negatively correlated with N value and overall expectation. These observations underscore the importance of considering the physical and psychologic aspects of patient care when planning dental treatment.

  15. Directed Assembly of Gold Nanoparticles

    DEFF Research Database (Denmark)

    Westerlund, Axel Rune Fredrik; Bjørnholm, Thomas

    2009-01-01

    As a complement to common "top-down" lithography techniques, "bottom-up" assembly techniques are emerging as promising tools to build nanoscale structures in a predictable way. Gold nanoparticles that are stable and relatively easy to synthesize are important building blocks in many such structures...... due to their useful optical and electronic properties. Programmed assembly of gold nanoparticles in one, two, and three dimensions is therefore of large interest. This review focuses on the progress from the last three years in the field of directed gold nanoparticle and nanorod assembly using...

  16. Illustrating how mechanical assemblies work

    KAUST Repository

    Mitra, Niloy J.

    2010-07-26

    How things work visualizations use a variety of visual techniques to depict the operation of complex mechanical assemblies. We present an automated approach for generating such visualizations. Starting with a 3D CAD model of an assembly, we first infer the motions of individual parts and the interactions between parts based on their geometry and a few user specified constraints. We then use this information to generate visualizations that incorporate motion arrows, frame sequences and animation to convey the causal chain of motions and mechanical interactions between parts. We present results for a wide variety of assemblies. © 2010 ACM.

  17. Illustrating how mechanical assemblies work

    KAUST Repository

    Mitra, Niloy J.

    2013-01-01

    How-things-work visualizations use a variety of visual techniques to depict the operation of complex mechanical assemblies. We present an automated approach for generating such visualizations. Starting with a 3D CAD model of an assembly, we first infer the motions of the individual parts and the interactions across the parts based on their geometry and a few user-specified constraints. We then use this information to generate visualizations that incorporate motion arrows, frame sequences, and animation to convey the causal chain of motions and mechanical interactions across parts. We demonstrate our system on a wide variety of assemblies. © 2013 ACM 0001-0782/13/01.

  18. Robotically Assembled Aerospace Structures: Digital Material Assembly using a Gantry-Type Assembler

    Science.gov (United States)

    Trinh, Greenfield; Copplestone, Grace; O'Connor, Molly; Hu, Steven; Nowak, Sebastian; Cheung, Kenneth; Jenett, Benjamin; Cellucci, Daniel

    2017-01-01

    This paper evaluates the development of automated assembly techniques for discrete lattice structures using a multi-axis gantry type CNC machine. These lattices are made of discrete components called digital materials. We present the development of a specialized end effector that works in conjunction with the CNC machine to assemble these lattices. With this configuration we are able to place voxels at a rate of 1.5 per minute. The scalability of digital material structures due to the incremental modular assembly is one of its key traits and an important metric of interest. We investigate the build times of a 5x5 beam structure on the scale of 1 meter (325 parts), 10 meters (3,250 parts), and 30 meters (9,750 parts). Utilizing the current configuration with a single end effector, performing serial assembly with a globally fixed feed station at the edge of the build volume, the build time increases according to a scaling law of n4, where n is the build scale. Build times can be reduced significantly by integrating feed systems into the gantry itself, resulting in a scaling law of n3. A completely serial assembly process will encounter time limitations as build scale increases. Automated assembly for digital materials can assemble high performance structures from discrete parts, and techniques such as built in feed systems, parallelization, and optimization of the fastening process will yield much higher throughput.

  19. Direct hierarchical assembly of nanoparticles

    Science.gov (United States)

    Xu, Ting; Zhao, Yue; Thorkelsson, Kari

    2014-07-22

    The present invention provides hierarchical assemblies of a block copolymer, a bifunctional linking compound and a nanoparticle. The block copolymers form one micro-domain and the nanoparticles another micro-domain.

  20. Analysis of Illumina Microbial Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Clum, Alicia; Foster, Brian; Froula, Jeff; LaButti, Kurt; Sczyrba, Alex; Lapidus, Alla; Woyke, Tanja

    2010-05-28

    Since the emerging of second generation sequencing technologies, the evaluation of different sequencing approaches and their assembly strategies for different types of genomes has become an important undertaken. Next generation sequencing technologies dramatically increase sequence throughput while decreasing cost, making them an attractive tool for whole genome shotgun sequencing. To compare different approaches for de-novo whole genome assembly, appropriate tools and a solid understanding of both quantity and quality of the underlying sequence data are crucial. Here, we performed an in-depth analysis of short-read Illumina sequence assembly strategies for bacterial and archaeal genomes. Different types of Illumina libraries as well as different trim parameters and assemblers were evaluated. Results of the comparative analysis and sequencing platforms will be presented. The goal of this analysis is to develop a cost-effective approach for the increased throughput of the generation of high quality microbial genomes.

  1. Multiple complementary gas distribution assemblies

    Science.gov (United States)

    Ng, Tuoh-Bin; Melnik, Yuriy; Pang, Lily L; Tuncel, Eda; Nguyen, Son T; Chen, Lu

    2016-04-05

    In one embodiment, an apparatus includes a first gas distribution assembly that includes a first gas passage for introducing a first process gas into a second gas passage that introduces the first process gas into a processing chamber and a second gas distribution assembly that includes a third gas passage for introducing a second process gas into a fourth gas passage that introduces the second process gas into the processing chamber. The first and second gas distribution assemblies are each adapted to be coupled to at least one chamber wall of the processing chamber. The first gas passage is shaped as a first ring positioned within the processing chamber above the second gas passage that is shaped as a second ring positioned within the processing chamber. The gas distribution assemblies may be designed to have complementary characteristic radial film growth rate profiles.

  2. Assembly delay line pulse generators

    CERN Document Server

    1971-01-01

    Assembly of six of the ten delay line pulse generators that will power the ten kicker magnet modules. One modulator part contains two pulse generators. Capacitors, inductances, and voltage dividers are in the oil tank on the left. Triggered high-pressure spark gap switches are on the platforms on the right. High voltage pulse cables to the kicker magnet emerge under the spark gaps. In the centre background are the assembled master gaps.

  3. Chromatin assembly using Drosophila systems.

    Science.gov (United States)

    Fyodorov, Dmitry V; Levenstein, Mark E

    2002-05-01

    To successfully study chromatin structure and activity in vitro, it is essential to have a chromatin assembly system that will prepare extended nucleosome arrays with highly defined protein content that resemble bulk chromatin isolated from living cell nuclei in terms of periodicity and nucleosome positioning. The Drosophila ATP-dependent chromatin assembly system described in this unit meets these requirements. The end product of the reaction described here has highly periodic extended arrays with physiologic spacing and positioning of the nucleosomes.

  4. Another successful Doctoral Student Assembly

    CERN Multimedia

    Katarina Anthony

    2014-01-01

    On Wednesday 2 April, CERN hosted its third Doctoral Student Assembly in the Council Chamber.   CERN PhD students show off their posters in CERN's Main Building. Speaking to a packed house, Director-General Rolf Heuer gave the assembly's opening speech and introduced the poster session that followed. Seventeen CERN PhD students presented posters on their work, and were greeted by their CERN and University supervisors. It was a very successful event!

  5. Precision Assembly of Systems on Surfaces (PASS)

    Science.gov (United States)

    2015-02-06

    Precision Assembly of Systems on Surfaces ( PASS ) This program was directed at generating functionalized surfaces and assemblies for electronic and...journals: Number of Papers published in non peer-reviewed journals: Final Report: Precision Assembly of Systems on Surfaces ( PASS ) Report Title This...PRECISION ASSEMBLY OF SYSTEMS ON SURFACES ( PASS ) PI: Timothy M. Swager Massachusetts Institute of Technology Final Report: DARPA, Defense

  6. Molecular self-assembly advances and applications

    CERN Document Server

    Dequan, Alex Li

    2012-01-01

    In the past several decades, molecular self-assembly has emerged as one of the main themes in chemistry, biology, and materials science. This book compiles and details cutting-edge research in molecular assemblies ranging from self-organized peptide nanostructures and DNA-chromophore foldamers to supramolecular systems and metal-directed assemblies, even to nanocrystal superparticles and self-assembled microdevices

  7. Product lifecycle-oriented virtual assembly technology

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-hua; NING Ru-xin; YAO Jun; WAN Bi-le

    2006-01-01

    VA (virtual assembly) provides a more efficient,intuitive and convenient method for assembly process modeling,simulation and analysis.Previous researches about VA are almost isolated and dispersive,and have not established the understanding and definition of VA from a macroscopical and integrated view.Based on the analysis of the connotations of VA,a PLO-VATA (product lifecycle-oriented virtual assembly technology architecture) is proposed,in this architecture,VA is decomposed into four basic elements:principles and methodology of DFA (design for assembly),assembly analysis and evaluation,virtual assembly model and virtual assembly toolkits.Immersion,concurrence,integration and collaboration are the four main characteristics of VA being put forward.The key techniques of VA including virtual assembly model,virtual assembly analysis and evaluation,and virtual assembly process planning are discussed.Finally,a prototype system is built to validate the feasibility of the proposed method.

  8. Assembly of lamins in vitro

    Institute of Scientific and Technical Information of China (English)

    MINGUNGWEI; XIANGJUNTONG; 等

    1996-01-01

    After lamins A,B and C were isolated and purified from rat liver,their assembly properties were examined by electron microscopy and scanning tunneling microscopy by electron microscopy and scanning tunneling microscopy using negative staining and the glycerol coating method,respectively.By varying the assembly time or the ionic conditions under which polymerization takes place,we have observed different stages of lamin assembly,which may provide clues on the structure of the 10 nm lamin filaments.At the first level of structural organization,two lamin polypeptides associate laterally into dimers with the two domains being parallel and in register.At the second level of structural organization,two dimers associate in a half-staggered and antiparallel fashion to form a tetramer 75 nm in length.At the third level of structural organization,4-10 lamin tetramers associate laterally in register to form 75 nm long 10nm filaments,which in turn combine head to head into long,fully assembled lamin filaments.The assembled lamin filaments are nonpolar.

  9. Dynamic pathways for viral capsid assembly

    OpenAIRE

    Hagan, Michael F.; Chandler, David

    2006-01-01

    We develop a class of models with which we simulate the assembly of particles into T1 capsid-like objects using Newtonian dynamics. By simulating assembly for many different values of system parameters, we vary the forces that drive assembly. For some ranges of parameters, assembly is facile, while for others, assembly is dynamically frustrated by kinetic traps corresponding to malformed or incompletely formed capsids. Our simulations sample many independent trajectories at various capsomer c...

  10. Dynamics of assembly production flow

    CERN Document Server

    Ezaki, Takahiro; Nishinari, Katsuhiro

    2015-01-01

    Despite recent developments in management theory, maintaining a manufacturing schedule remains difficult because of production delays and fluctuations in demand and supply of materials. The response of manufacturing systems to such disruptions to dynamic behavior has been rarely studied. To capture these responses, we investigate a process that models the assembly of parts into end products. The complete assembly process is represented by a directed tree, where the smallest parts are injected at leaves and the end products are removed at the root. A discrete assembly process, represented by a node on the network, integrates parts, which are then sent to the next downstream node as a single part. The model exhibits some intriguing phenomena, including overstock cascade, phase transition in terms of demand and supply fluctuations, nonmonotonic distribution of stockout in the network, and the formation of a stockout path and stockout chains. Surprisingly, these rich phenomena result from only the nature of distr...

  11. Assembling of hydrogenated aluminum clusters

    Energy Technology Data Exchange (ETDEWEB)

    Duque, F.; Mananes, A. [Dept. de Fisica Moderna, Universidad de Cantabria, Santander (Spain); Molina, L.M.; Lopez, M.J.; Alonso, J.A. [Dept. de Fisica Teorica, Universidad de Valladolid (Spain)

    2001-09-01

    The electronic and atomic structure of Al{sub 13}H has been studied using Density Functional Theory. Al{sub 13}H has closed electronic shells. This makes the cluster very stable and suggests that it could be a candidate to form cluster assembled solids. The interaction between two Al{sub 13}H clusters was analyzed and we found that the two units preserve their identities in the dimer. A cubic-like solid phase assembled from Al{sub 13}H units was then modeled. In that solid the clusters retain much of their identity. Molecular dynamics runs show that the structure of the assembled solid is stable at least up to 150 K. A favorable relative orientation of the clusters with respect to their neighbors is critical for the stability of that solid. (orig.)

  12. Workload analyse of assembling process

    Science.gov (United States)

    Ghenghea, L. D.

    2015-11-01

    The workload is the most important indicator for managers responsible of industrial technological processes no matter if these are automated, mechanized or simply manual in each case, machines or workers will be in the focus of workload measurements. The paper deals with workload analyses made to a most part manual assembling technology for roller bearings assembling process, executed in a big company, with integrated bearings manufacturing processes. In this analyses the delay sample technique have been used to identify and divide all bearing assemblers activities, to get information about time parts from 480 minutes day work time that workers allow to each activity. The developed study shows some ways to increase the process productivity without supplementary investments and also indicated the process automation could be the solution to gain maximum productivity.

  13. FUEL ASSEMBLY SHAKER TEST SIMULATION

    Energy Technology Data Exchange (ETDEWEB)

    Klymyshyn, Nicholas A.; Sanborn, Scott E.; Adkins, Harold E.; Hanson, Brady D.

    2013-05-30

    This report describes the modeling of a PWR fuel assembly under dynamic shock loading in support of the Sandia National Laboratories (SNL) shaker test campaign. The focus of the test campaign is on evaluating the response of used fuel to shock and vibration loads that a can occur during highway transport. Modeling began in 2012 using an LS-DYNA fuel assembly model that was first created for modeling impact scenarios. SNL’s proposed test scenario was simulated through analysis and the calculated results helped guide the instrumentation and other aspects of the testing. During FY 2013, the fuel assembly model was refined to better represent the test surrogate. Analysis of the proposed loads suggested the frequency band needed to be lowered to attempt to excite the lower natural frequencies of the fuel assembly. Despite SNL’s expansion of lower frequency components in their five shock realizations, pretest predictions suggested a very mild dynamic response to the test loading. After testing was completed, one specific shock case was modeled, using recorded accelerometer data to excite the model. Direct comparison of predicted strain in the cladding was made to the recorded strain gauge data. The magnitude of both sets of strain (calculated and recorded) are very low, compared to the expected yield strength of the Zircaloy-4 material. The model was accurate enough to predict that no yielding of the cladding was expected, but its precision at predicting micro strains is questionable. The SNL test data offers some opportunity for validation of the finite element model, but the specific loading conditions of the testing only excite the fuel assembly to respond in a limited manner. For example, the test accelerations were not strong enough to substantially drive the fuel assembly out of contact with the basket. Under this test scenario, the fuel assembly model does a reasonable job of approximating actual fuel assembly response, a claim that can be verified through

  14. Apollo Telescope Mount Spar Assembly

    Science.gov (United States)

    1969-01-01

    The Apollo Telescope Mount (ATM), designed and developed by the Marshall Space Flight Center, served as the primary scientific instrument unit aboard the Skylab. The ATM contained eight complex astronomical instruments designed to observe the Sun over a wide spectrum from visible light to x-rays. This image shows the ATM spar assembly. All solar telescopes, the fine Sun sensors, and some auxiliary systems are mounted on the spar, a cruciform lightweight perforated metal mounting panel that divides the 10-foot long canister lengthwise into four equal compartments. The spar assembly was nested inside a cylindrical canister that fit into the rack, a complex frame, and was protected by the solar shield.

  15. Self-assembly of cyclodextrins

    DEFF Research Database (Denmark)

    Fülöp, Z.; Kurkov, S.V.; Nielsen, T.T.;

    2012-01-01

    The design of functional cyclodextrin (CD) nanoparticles is a developing area in the field of nanomedicine. CDs can not only help in the formation of drug carriers but also increase the local concentration of drugs at the site of action. CD monomers form aggregates by self-assembly, a tendency...... that increases upon formation of inclusion complexes with lipophilic drugs. However, the stability of such aggregates is not sufficient for parenteral administration. In this review CD polymers and CD containing nanoparticles are categorized, with focus on self-assembled CD nanoparticles. It is described how...... the nanoparticles can be stabilized and tuned to have specific properties....

  16. Ultrasonic Assembly of Thermoplastic Parts

    Energy Technology Data Exchange (ETDEWEB)

    Schurman, W. R.

    1970-03-31

    Four ultrasonic methods were evaluated for assembly of experimental plastic parts for detonators: (1) welding, (2) crimping and staking, (3) insertion, and (4) reactivation of adhesives. For welding, staking and insertion, plastics with low elastic moduli, such as acrylics and polycarbonate, produced the best results. Thermosetting, hot-melt, and solution adhesives could all be activated ultrasonically to form good bonds on plastics and other materials. This evaluation indicated that thermoplastic detonator parts could be assembled ultrasonically in shorter times than by present production techniques with high bond strengths and high product acceptance rates.

  17. STAR: a simple TAL effector assembly reaction using isothermal assembly.

    Science.gov (United States)

    Gogolok, Sabine; Garcia-Diaz, Claudia; Pollard, Steven M

    2016-09-12

    Transcription activator-like effectors (TALEs) contain modular programmable DNA binding domains. Fusing TALEs with effector domains creates synthetic transcription factors (TALE-TFs) or nucleases (TALENs), enabling precise gene manipulations. The construction of TALEs remains challenging due to their repetitive sequences. Here we report a simple TALE assembly reaction (STAR) that enables individual laboratories to generate multiple TALEs in a facile manner. STAR uses an isothermal assembly ('Gibson assembly') that is labour- and cost-effective, accessible, rapid and scalable. A small 68-part fragment library is employed, and the specific TALE repeat sequence is generated within ~8 hours. Sequence-verified TALENs or TALE-TF plasmids targeting 17 bp target sequences can be produced within three days, without the need for stepwise intermediate plasmid production. We demonstrate the utility of STAR through production of functional TALE-TFs capable of activating human SOX2 expression. STAR addresses some of the shortcomings of existing Golden Gate or solid-phase assembly protocols and enables routine production of TALE-TFs that will complement emerging CRISPR/Cas9-based reagents across diverse applications in mammalian stem cell and synthetic biology.

  18. "Assembling" the Ideal Learner: The School Assembly as Regulatory Ritual

    Science.gov (United States)

    Silbert, Patti; Jacklin, Heather

    2015-01-01

    "School assemblies" are rituals that celebrate and mark the school community. They carry messages of allegiance and belonging that are disseminated both verbally and nonverbally. Although verbal messages are explicitly stated, nonverbal messages are conveyed through subjection to habits, rules, and orders (Foucault 1977) and are…

  19. iAssembler: a package for de novo assembly of Roche-454/Sanger transcriptome sequences

    Directory of Open Access Journals (Sweden)

    Zheng Yi

    2011-11-01

    Full Text Available Abstract Background Expressed Sequence Tags (ESTs have played significant roles in gene discovery and gene functional analysis, especially for non-model organisms. For organisms with no full genome sequences available, ESTs are normally assembled into longer consensus sequences for further downstream analysis. However current de novo EST assembly programs often generate large number of assembly errors that will negatively affect the downstream analysis. In order to generate more accurate consensus sequences from ESTs, tools are needed to reduce or eliminate errors from de novo assemblies. Results We present iAssembler, a pipeline that can assemble large-scale ESTs into consensus sequences with significantly higher accuracy than current existing assemblers. iAssembler employs MIRA and CAP3 assemblers to generate initial assemblies, followed by identifying and correcting two common types of transcriptome assembly errors: 1 ESTs from different transcripts (mainly alternatively spliced transcripts or paralogs are incorrectly assembled into same contigs; and 2 ESTs from same transcripts fail to be assembled together. iAssembler can be used to assemble ESTs generated using the traditional Sanger method and/or the Roche-454 massive parallel pyrosequencing technology. Conclusion We compared performances of iAssembler and several other de novo EST assembly programs using both Roche-454 and Sanger EST datasets. It demonstrated that iAssembler generated significantly more accurate consensus sequences than other assembly programs.

  20. Focal Plane Image Assembly of Subpixel

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper describes the scanning assembly principle and construction of scanning assembly sample.The factors that affect assembly accuracy are analyzed.There are two steps in CCD focal plane scanning assembly.The first is rough assembly,and the second is accurate assembly.In this paper,the moiré fringe is introduced in judging assembly accuracy directly and accurately.The equation for optical transmission characteristics of CCD Moiré fringes is presented.The measurement of Moiré fringes can be completed when some conditions are satisfied.2D-assembly error can be obtained by using digital correlation filtering technique.Finally,the result of focal plane scanning assembly is presented.The result is in good accordance with theory.

  1. Assembly Sequence Planning for Mechanical Products

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    A method for assembly sequence planning is proposed in this paper. First, two methods for assembly sequence planning are compared, which are indirect method and direct method. Then, the limits of the previous assembly planning system are pointed out. On the basis of indirect method, an improved method for assembly sequence planning is put forward. This method is composed of four parts, which are assembly modeling for products, assembly sequence representing, assembly sequence planning, and evaluation and optimization. The assembly model is established by human machine interaction, and the assembly model contains components' information and the assembly relation among the components. The assembly sequence planning is based on the breaking up of the assembly model. And/or graph is used to represent assembly sequence set. Every component which satisfies the disassembly condition is recorded as a node of an and/or graph. After the disassembly sequence and/or graph is generated, heuristic algorithm - AO* algorithm is used to search the disassembly sequence and/or graph, and the optimum assembly sequence planning is realized. This method is proved to be effective in a prototype system which is a sub-project of a state 863/CIMS research project of China - ‘Concurrent Engineering’.

  2. DNA-guided nanoparticle assemblies

    Science.gov (United States)

    Gang, Oleg; Nykypanchuk, Dmytro; Maye, Mathew; van der Lelie, Daniel

    2013-07-16

    In some embodiments, DNA-capped nanoparticles are used to define a degree of crystalline order in assemblies thereof. In some embodiments, thermodynamically reversible and stable body-centered cubic (bcc) structures, with particles occupying nanoparticles linked by nucleic acid sequences and forming an open crystal structure with catalytically active agents attached to the crystal on its surface or in interstices.

  3. Quantum magnetism through atomic assembly

    NARCIS (Netherlands)

    Spinelli, A.

    2015-01-01

    This thesis presents an experimental study of magnetic structures, composed of only a few atoms. Those structures are first built atom-by-atom and then locally probed, both with a low-temperature STM. The technique that we use to assemble them is vertical atom manipulation, while to study their phy

  4. Construction of YBS Critical Assembly

    Institute of Scientific and Technical Information of China (English)

    ZHOU; Qi; LIANG; Shu-hong; ZHU; Qing-fu; ZHANG; Wei; YANG; Li-jun; QUAN; Yan-hui

    2015-01-01

    Supported by the XDA program of CAS,the YBS critical assembly has been constructed for the experimental research of the coupling and influence characteristics of spallation target and reactor in ADS system.This work consists of two parts:one is the conversion of the reactor hall and control room,and the other manufacture,installation and commissioning of the critical

  5. In vitro assembly of catalase.

    Science.gov (United States)

    Baureder, Michael; Barane, Elisabeth; Hederstedt, Lars

    2014-10-10

    Most aerobic organisms contain catalase, which functions to decompose hydrogen peroxide. Typical catalases are structurally complex homo-tetrameric enzymes with one heme prosthetic group buried in each subunit. It is not known how catalase in the cell is assembled from its constituents. The bacterium Enterococcus faecalis cannot synthesize heme but can acquire it from the environment to form a cytoplasmic catalase. We have in E. faecalis monitored production of the enzyme polypeptide (KatA) depending on the availability of heme and used our findings to devise a procedure for the purification of preparative amounts of in vivo-synthesized apocatalase. We show that fully active catalase can be obtained in vitro by incubating isolated apoprotein with hemin. We have characterized features of the assembly process and describe a temperature-trapped hemylated intermediate of the enzyme maturation process. Hemylation of apocatalase does not require auxiliary cell components, but rapid assembly of active enzyme seemingly is assisted in the cell. Our findings provide insight about catalase assembly and offer new experimental possibilities for detailed studies of this process.

  6. Automated Solar-Array Assembly

    Science.gov (United States)

    Soffa, A.; Bycer, M.

    1982-01-01

    Large arrays are rapidly assembled from individual solar cells by automated production line developed for NASA's Jet Propulsion Laboratory. Apparatus positions cells within array, attaches interconnection tabs, applies solder flux, and solders interconnections. Cells are placed in either straight or staggered configurations and may be connected either in series or in parallel. Are attached at rate of one every 5 seconds.

  7. Dynamics of assembly production flow

    Science.gov (United States)

    Ezaki, Takahiro; Yanagisawa, Daichi; Nishinari, Katsuhiro

    2015-06-01

    Despite recent developments in management theory, maintaining a manufacturing schedule remains difficult because of production delays and fluctuations in demand and supply of materials. The response of manufacturing systems to such disruptions to dynamic behavior has been rarely studied. To capture these responses, we investigate a process that models the assembly of parts into end products. The complete assembly process is represented by a directed tree, where the smallest parts are injected at leaves and the end products are removed at the root. A discrete assembly process, represented by a node on the network, integrates parts, which are then sent to the next downstream node as a single part. The model exhibits some intriguing phenomena, including overstock cascade, phase transition in terms of demand and supply fluctuations, nonmonotonic distribution of stockout in the network, and the formation of a stockout path and stockout chains. Surprisingly, these rich phenomena result from only the nature of distributed assembly processes. From a physical perspective, these phenomena provide insight into delay dynamics and inventory distributions in large-scale manufacturing systems.

  8. ATLAS Assembly Hall Open Day

    CERN Document Server

    Patrice Loiez

    2004-01-01

    To mark the 50th Anniversary of the founding of CERN, a day of tours, displays and presentations was held in October 2004. The assembly halls for the experiments that were waiting to be installed on the LHC, such as ATLAS shown here, were transformed into display areas and cafés.

  9. HIV-1 assembly in macrophages

    Directory of Open Access Journals (Sweden)

    Benaroch Philippe

    2010-04-01

    Full Text Available Abstract The molecular mechanisms involved in the assembly of newly synthesized Human Immunodeficiency Virus (HIV particles are poorly understood. Most of the work on HIV-1 assembly has been performed in T cells in which viral particle budding and assembly take place at the plasma membrane. In contrast, few studies have been performed on macrophages, the other major target of HIV-1. Infected macrophages represent a viral reservoir and probably play a key role in HIV-1 physiopathology. Indeed macrophages retain infectious particles for long periods of time, keeping them protected from anti-viral immune response or drug treatments. Here, we present an overview of what is known about HIV-1 assembly in macrophages as compared to T lymphocytes or cell lines. Early electron microscopy studies suggested that viral assembly takes place at the limiting membrane of an intracellular compartment in macrophages and not at the plasma membrane as in T cells. This was first considered as a late endosomal compartment in which viral budding seems to be similar to the process of vesicle release into multi-vesicular bodies. This view was notably supported by a large body of evidence involving the ESCRT (Endosomal Sorting Complex Required for Transport machinery in HIV-1 budding, the observation of viral budding profiles in such compartments by immuno-electron microscopy, and the presence of late endosomal markers associated with macrophage-derived virions. However, this model needs to be revisited as recent data indicate that the viral compartment has a neutral pH and can be connected to the plasma membrane via very thin micro-channels. To date, the exact nature and biogenesis of the HIV assembly compartment in macrophages remains elusive. Many cellular proteins potentially involved in the late phases of HIV-1 cycle have been identified; and, recently, the list has grown rapidly with the publication of four independent genome-wide screens. However, their respective

  10. DESIGN REUSE METHOD FOR ASSEMBLIES IN CONCEPT DESIGN

    Institute of Scientific and Technical Information of China (English)

    Dong Yan; Tan Jianrong; Xu Jing

    2005-01-01

    Aiming at difficult sorting and retrieving complicated structure assemblies in assembly lib,a method for compartmentalizing assembly design resource by conceptual product structure model is presented. The similar assembly retrieval mechanisms of symbol assembly relation graph matching and symbol assembly relation graph similarity are discussed. The method is validated by taking valve rod assemblies as example.

  11. Minimus: a fast, lightweight genome assembler

    Directory of Open Access Journals (Sweden)

    Salzberg Steven L

    2007-02-01

    Full Text Available Abstract Background Genome assemblers have grown very large and complex in response to the need for algorithms to handle the challenges of large whole-genome sequencing projects. Many of the most common uses of assemblers, however, are best served by a simpler type of assembler that requires fewer software components, uses less memory, and is far easier to install and run. Results We have developed the Minimus assembler to address these issues, and tested it on a range of assembly problems. We show that Minimus performs well on several small assembly tasks, including the assembly of viral genomes, individual genes, and BAC clones. In addition, we evaluate Minimus' performance in assembling bacterial genomes in order to assess its suitability as a component of a larger assembly pipeline. We show that, unlike other software currently used for these tasks, Minimus produces significantly fewer assembly errors, at the cost of generating a more fragmented assembly. Conclusion We find that for small genomes and other small assembly tasks, Minimus is faster and far more flexible than existing tools. Due to its small size and modular design Minimus is perfectly suited to be a component of complex assembly pipelines. Minimus is released as an open-source software project and the code is available as part of the AMOS project at Sourceforge.

  12. Hydraulic Experiment for Simulative Assemblies of Blanket Assembly and Np Transmutation Assembly of China Experimental Fast Reactor

    Institute of Scientific and Technical Information of China (English)

    CHENG; Dao-xi; QI; Xiao-guang; ZHAI; Wei-ming; YANG; Bing; ZHOU; Ping

    2013-01-01

    The out-of reactor hydraulic experiment of fast reactor assembly is one of the important experiments in the process of the development of the fast reactor assembly.In this experiment,the size of the throttling element in the foot of the assembly is decided which is fit for the flow division in the reactor and the

  13. Self-assembly of self-assembled molecular triangles

    Indian Academy of Sciences (India)

    Mili C Naranthatta; V Ramkumar; Dillip Kumar Chand

    2014-09-01

    A rare variety of self-assembledmolecular triangle [Pd3(bpy)3(imidazolate)3](NO3)3, 1 is prepared by the combination of Pd(bpy)(NO3)2 with imidazole, at 1:1 ratio, in acetonitrile-water. Deprotonation of imidazole happened during the course of the complexation reaction where upon the metallomacrocycle is formed. The bowl-shaped trinuclear architecture of 1 is crafted with three peripheral bpy units capable of - stacking interactions. While the solution state structure of 1 can be best described as a trinuclear complex, in the solidstate well-fashioned intermolecular - and CH- interactions are observed. Thus, in the solid-state further self-assembly of already self-assembled molecular triangle is witnessed. The triangular panels are arranged in a linear manner utilizing intermolecular - interactions where upon two out of three bpy units of each molecule participated in the chain formation.

  14. Detonator assembly for oil well perforating gun

    Energy Technology Data Exchange (ETDEWEB)

    Regalbuto, J.A.

    1981-02-18

    A safe/arm detonator assembly for use with an oil well perforating gun assembly has 2 housing members isolated from well-bore fluid which are rotatable from a safe position wherein a detonator and a booster are held out of alignment, to an armed position wherein the detonator and booster are moved into alignment. The detonator assembly is further arranged to be installed in a well perforating gun assembly such that the gun assembly may be transported with the detonator assembly in the safe position, and rotated to the armed position at the well site without disassembling the gun assembly. A safety pin may protrude from one of the housing members across a cavity between the members to cover and protect the booster from accidental detonation when the detonator assembly is in the safe position. The detonator and booster cavities may be held aligned by a detent ball. 16 claims.

  15. Compact MCP assemblies for mass spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Matsuura, S. [Hamamatsu Photonics K.K., Shizuoka (Japan). Electron Tube Div.; Umebayashi, S. [Hamamatsu Photonics K.K., Shizuoka (Japan). Electron Tube Div.; Kusuyama, Y. [Hamamatsu Photonics K.K., Shizuoka (Japan). Electron Tube Div.; Natsume, Y. [Hamamatsu Photonics K.K., Shizuoka (Japan). Electron Tube Div.; Oba, K. [Hamamatsu Photonics K.K., Shizuoka (Japan). Electron Tube Div.

    1995-09-01

    We have developed compact microchannel plate (MCP) assemblies which have a high gain, good pulse height resolution and a fast response for MS applications. In this paper, these new assemblies are described referring to their structures, functions and characteristics. (orig.).

  16. STAR: a simple TAL effector assembly reaction using isothermal assembly

    Science.gov (United States)

    Gogolok, Sabine; Garcia-Diaz, Claudia; Pollard, Steven M.

    2016-01-01

    Transcription activator-like effectors (TALEs) contain modular programmable DNA binding domains. Fusing TALEs with effector domains creates synthetic transcription factors (TALE-TFs) or nucleases (TALENs), enabling precise gene manipulations. The construction of TALEs remains challenging due to their repetitive sequences. Here we report a simple TALE assembly reaction (STAR) that enables individual laboratories to generate multiple TALEs in a facile manner. STAR uses an isothermal assembly (‘Gibson assembly’) that is labour- and cost-effective, accessible, rapid and scalable. A small 68-part fragment library is employed, and the specific TALE repeat sequence is generated within ~8 hours. Sequence-verified TALENs or TALE-TF plasmids targeting 17 bp target sequences can be produced within three days, without the need for stepwise intermediate plasmid production. We demonstrate the utility of STAR through production of functional TALE-TFs capable of activating human SOX2 expression. STAR addresses some of the shortcomings of existing Golden Gate or solid-phase assembly protocols and enables routine production of TALE-TFs that will complement emerging CRISPR/Cas9-based reagents across diverse applications in mammalian stem cell and synthetic biology. PMID:27615025

  17. Virtual Reality and Haptics for Product Assembly

    Directory of Open Access Journals (Sweden)

    Maria Teresa Restivo

    2012-01-01

    Full Text Available Haptics can significantly enhance the user's sense of immersion and interactivity. An industrial application of virtual reality and haptics for product assembly is described in this paper, which provides a new and low-cost approach for product assembly design, assembly task planning and assembly operation training. A demonstration of the system with haptics device interaction was available at the session of exp.at'11.

  18. Snowball: Strain aware gene assembly of Metagenomes

    OpenAIRE

    Gregor, I.; Schönhuth, A.; McHardy, A. C.

    2015-01-01

    Gene assembly is an important step in functional analysis of shotgun metagenomic data. Nonetheless, strain aware assembly remains a challenging task, as current assembly tools often fail to distinguish among strain variants or require closely related reference genomes of the studied species to be available. We have developed Snowball, a novel strain aware and reference-free gene assembler for shotgun metagenomic data. It uses profile hidden Markov models (HMMs) of gene domains of interest to ...

  19. United assembly algorithm for optical burst switching

    Institute of Scientific and Technical Information of China (English)

    Jinhui Yu(于金辉); Yijun Yang(杨教军); Yuehua Chen(陈月华); Ge Fan(范戈)

    2003-01-01

    Optical burst switching (OBS) is a promising optical switching technology. The burst assembly algorithm controls burst assembly, which significantly impacts performance of OBS network. This paper provides a new assembly algorithm, united assembly algorithm, which has more practicability than conventional algorithms. In addition, some factors impacting selections of parameters of this algorithm are discussed and the performance of this algorithm is studied by computer simulation.

  20. Radiation Effects Simulation of Fuel Assemblies

    Institute of Scientific and Technical Information of China (English)

    CUI; Yao

    2015-01-01

    Due to a large number of photons irradiated by the fuel assemblies after radiation in the reactor,the data acquisition and image reconstruction will be interfered seriously for the nuclear fuel assembly non-destructive testing system.Therefore,in process of the fuel assembly NDT system

  1. 49 CFR 572.186 - Abdomen assembly.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Abdomen assembly. 572.186 Section 572.186... Dummy, 50th Percentile Adult Male § 572.186 Abdomen assembly. (a) The abdomen assembly (175-5000) is...). When subjected to tests procedures specified in paragraph (b) of this section, the abdomen...

  2. Snowball: Strain aware gene assembly of Metagenomes

    NARCIS (Netherlands)

    Gregor, I.; Schönhuth, A.; McHardy, A.C.

    2015-01-01

    Gene assembly is an important step in functional analysis of shotgun metagenomic data. Nonetheless, strain aware assembly remains a challenging task, as current assembly tools often fail to distinguish among strain variants or require closely related reference genomes of the studied species to be av

  3. Supramolecular assemblies based on glycoconjugated dyes

    NARCIS (Netherlands)

    Schmidt, Bettina

    2016-01-01

    Supramolecular assemblies of glycoconjugated dyes can be tailored with properties that make them attractive for use in biomedical applications. For example, when assemblies of glycoconjugated dyes are displaying carbohydrates on their periphery in a polyvalent manner, these assemblies can be used to

  4. LHC Magnet Assembly Facility in building 181

    CERN Multimedia

    CERN Video Productions

    2005-01-01

    Hall 181 activities for the LHC machine * Reception of the American magnets : quadrupoles and separation dipoles * Assembly of the string Low-Beta Triplet -Q2-Q3-DFBX-D1 * Insertion quadrupoles cold masses assembly * Magnets reception type MQM, MQY, MCBC et MCBY * Assembly in the shell * Longitudinal welding under the press * Equipment with end covers in the finishing area

  5. Reversibly assembled cellular composite materials.

    Science.gov (United States)

    Cheung, Kenneth C; Gershenfeld, Neil

    2013-09-13

    We introduce composite materials made by reversibly assembling a three-dimensional lattice of mass-produced carbon fiber-reinforced polymer composite parts with integrated mechanical interlocking connections. The resulting cellular composite materials can respond as an elastic solid with an extremely large measured modulus for an ultralight material (12.3 megapascals at a density of 7.2 milligrams per cubic centimeter). These materials offer a hierarchical decomposition in modeling, with bulk properties that can be predicted from component measurements and deformation modes that can be determined by the placement of part types. Because site locations are locally constrained, structures can be produced in a relative assembly process that merges desirable features of fiber composites, cellular materials, and additive manufacturing.

  6. Linear Logic for Meaning Assembly

    CERN Document Server

    Dalrymple, M; Pereira, F C N; Saraswat, V; Dalrymple, Mary; Lamping, John; Pereira, Fernando; Saraswat, Vijay

    1995-01-01

    Semantic theories of natural language associate meanings with utterances by providing meanings for lexical items and rules for determining the meaning of larger units given the meanings of their parts. Meanings are often assumed to combine via function application, which works well when constituent structure trees are used to guide semantic composition. However, we believe that the functional structure of Lexical-Functional Grammar is best used to provide the syntactic information necessary for constraining derivations of meaning in a cross-linguistically uniform format. It has been difficult, however, to reconcile this approach with the combination of meanings by function application. In contrast to compositional approaches, we present a deductive approach to assembling meanings, based on reasoning with constraints, which meshes well with the unordered nature of information in the functional structure. Our use of linear logic as a `glue' for assembling meanings allows for a coherent treatment of the LFG requ...

  7. Regenerator cross arm seal assembly

    Science.gov (United States)

    Jackman, Anthony V.

    1988-01-01

    A seal assembly for disposition between a cross arm on a gas turbine engine block and a regenerator disc, the seal assembly including a platform coextensive with the cross arm, a seal and wear layer sealingly and slidingly engaging the regenerator disc, a porous and compliant support layer between the platform and the seal and wear layer porous enough to permit flow of cooling air therethrough and compliant to accommodate relative thermal growth and distortion, a dike between the seal and wear layer and the platform for preventing cross flow through the support layer between engine exhaust and pressurized air passages, and air diversion passages for directing unregenerated pressurized air through the support layer to cool the seal and wear layer and then back into the flow of regenerated pressurized air.

  8. Structural Assembly Demonstration Experiment (SADE)

    Science.gov (United States)

    Akin, David L.; Mills, Raymond A.; Bowden, Mary L.

    1987-01-01

    The purpose of the Structural Assembly Demonstration Experiment (SADE) was to create a near-term Shuttle flight experiment focusing on the deployment and erection of structural truss elements. The activities of the MIT Space Systems Laboratory consist of three major areas: preparing and conducting neutral buoyancy simulation test series; producing a formal SADE Experiment plan; and studying the structural dynamics issues of the truss structure. Each of these areas is summarized.

  9. 49 CFR 393.93 - Seats, seat belt assemblies, and seat belt assembly anchorages.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Seats, seat belt assemblies, and seat belt... § 393.93 Seats, seat belt assemblies, and seat belt assembly anchorages. (a) Buses—(1) Buses... the driver's seat and seat belt assembly anchorages that conform to the location and...

  10. Self-assembled plasmonic metamaterials

    Science.gov (United States)

    Mühlig, Stefan; Cunningham, Alastair; Dintinger, José; Scharf, Toralf; Bürgi, Thomas; Lederer, Falk; Rockstuhl, Carsten

    2013-07-01

    Nowadays for the sake of convenience most plasmonic nanostructures are fabricated by top-down nanofabrication technologies. This offers great degrees of freedom to tailor the geometry with unprecedented precision. However, it often causes disadvantages as well. The structures available are usually planar and periodically arranged. Therefore, bulk plasmonic structures are difficult to fabricate and the periodic arrangement causes undesired effects, e.g., strong spatial dispersion is observed in metamaterials. These limitations can be mitigated by relying on bottom-up nanofabrication technologies. There, self-assembly methods and techniques from the field of colloidal nanochemistry are used to build complex functional unit cells in solution from an ensemble of simple building blocks, i.e., in most cases plasmonic nanoparticles. Achievable structures are characterized by a high degree of nominal order only on a short-range scale. The precise spatial arrangement across larger dimensions is not possible in most cases; leading essentially to amorphous structures. Such self-assembled nanostructures require novel analytical means to describe their properties, innovative designs of functional elements that possess a desired near- and far-field response, and entail genuine nanofabrication and characterization techniques. Eventually, novel applications have to be perceived that are adapted to the specifics of the self-assembled nanostructures. This review shall document recent progress in this field of research. Emphasis is put on bottom-up amorphous metamaterials. We document the state-of-the-art but also critically assess the problems that have to be overcome.

  11. Automated solar module assembly line

    Science.gov (United States)

    Bycer, M.

    1980-08-01

    The solar module assembly machine which Kulicke and Soffa delivered under this contract is a cell tabbing and stringing machine, and capable of handling a variety of cells and assembling strings up to 4 feet long which then can be placed into a module array up to 2 feet by 4 feet in a series of parallel arrangement, and in a straight or interdigitated array format. The machine cycle is 5 seconds per solar cell. This machine is primarily adapted to 3 inch diameter round cells with two tabs between cells. Pulsed heat is used as the bond technique for solar cell interconnects. The solar module assembly machine unloads solar cells from a cassette, automatically orients them, applies flux and solders interconnect ribbons onto the cells. It then inverts the tabbed cells, connects them into cell strings, and delivers them into a module array format using a track mounted vacuum lance, from which they are taken to test and cleaning benches prior to final encapsulation into finished solar modules. Throughout the machine the solar cell is handled very carefully, and any contact with the collector side of the cell is avoided or minimized.

  12. Assembly modes of dragonfly wings.

    Science.gov (United States)

    Zhao, Hong-Xiao; Yin, Ya-Jun; Zhong, Zheng

    2011-12-01

    The assembly modes of dragonfly wings are observed through FEG-ESEM. Different from airplane wings, dragonfly wings are found to be assembled through smooth transition mode and global package mode. First, at the vein/membrane conjunctive site, the membrane is divided into upper and lower portions from the center layer and transited smoothly to the vein. Then the two portions pack the vein around and form the outer surface of the vein. Second, at the vein/spike conjunctive site, the vein and spike are connected smoothly into a triplet. Last, at the vein/membrane/spike conjunctive site, the membrane (i.e., the outer layer of the vein) transits smoothly to the spike, packs it around, and forms its outer layer. In short, the membrane looks like a closed coat packing the wing as a whole. The smooth transition mode and the global package mode are universal assembly modes in dragonfly wings. They provide us the references for better understanding of the functions of dragonfly wings and the bionic manufactures of the wings of flights with mini sizes.

  13. AGORA: Assembly Guided by Optical Restriction Alignment

    Directory of Open Access Journals (Sweden)

    Lin Henry C

    2012-08-01

    Full Text Available Abstract Background Genome assembly is difficult due to repeated sequences within the genome, which create ambiguities and cause the final assembly to be broken up into many separate sequences (contigs. Long range linking information, such as mate-pairs or mapping data, is necessary to help assembly software resolve repeats, thereby leading to a more complete reconstruction of genomes. Prior work has used optical maps for validating assemblies and scaffolding contigs, after an initial assembly has been produced. However, optical maps have not previously been used within the genome assembly process. Here, we use optical map information within the popular de Bruijn graph assembly paradigm to eliminate paths in the de Bruijn graph which are not consistent with the optical map and help determine the correct reconstruction of the genome. Results We developed a new algorithm called AGORA: Assembly Guided by Optical Restriction Alignment. AGORA is the first algorithm to use optical map information directly within the de Bruijn graph framework to help produce an accurate assembly of a genome that is consistent with the optical map information provided. Our simulations on bacterial genomes show that AGORA is effective at producing assemblies closely matching the reference sequences. Additionally, we show that noise in the optical map can have a strong impact on the final assembly quality for some complex genomes, and we also measure how various characteristics of the starting de Bruijn graph may impact the quality of the final assembly. Lastly, we show that a proper choice of restriction enzyme for the optical map may substantially improve the quality of the final assembly. Conclusions Our work shows that optical maps can be used effectively to assemble genomes within the de Bruijn graph assembly framework. Our experiments also provide insights into the characteristics of the mapping data that most affect the performance of our algorithm, indicating the

  14. Robust, directed assembly of fluorescent nanodiamonds.

    Science.gov (United States)

    Kianinia, Mehran; Shimoni, Olga; Bendavid, Avi; Schell, Andreas W; Randolph, Steven J; Toth, Milos; Aharonovich, Igor; Lobo, Charlene J

    2016-10-27

    Arrays of fluorescent nanoparticles are highly sought after for applications in sensing, nanophotonics and quantum communications. Here we present a simple and robust method of assembling fluorescent nanodiamonds into macroscopic arrays. Remarkably, the yield of this directed assembly process is greater than 90% and the assembled patterns withstand ultra-sonication for more than three hours. The assembly process is based on covalent bonding of carboxyl to amine functional carbon seeds and is applicable to any material, and to non-planar surfaces. Our results pave the way to directed assembly of sensors and nanophotonics devices.

  15. Robust, directed assembly of fluorescent nanodiamonds

    CERN Document Server

    Kianinia, Mehran; Shimoni, Olga; Randolph, Steven J; Toth, Milos; Aharonovich, Igor; Lobo, Charlene J

    2016-01-01

    Arrays of fluorescent nanoparticles are highly sought after for applications in sensing and nanophotonics. Here we present a simple and robust method of assembling fluorescent nanodiamonds into macroscopic arrays. Remarkably, the yield of this directed assembly process is greater than 90% and the assembled patterns withstand ultra-sonication for more than three hours. The assembly process is based on covalent bonding of carboxyl to amine functional carbon seeds and is applicable to any material, and to non-planar surfaces. Our results pave the way to directed assembly of sensing and nanophotonics devices.

  16. Observations and Models of Galaxy Assembly Bias

    Science.gov (United States)

    Campbell, Duncan A.

    2017-01-01

    The assembly history of dark matter haloes imparts various correlations between a halo’s physical properties and its large scale environment, i.e. assembly bias. It is common for models of the galaxy-halo connection to assume that galaxy properties are only a function of halo mass, implicitly ignoring how assembly bias may affect galaxies. Recently, programs to model and constrain the degree to which galaxy properties are influenced by assembly bias have been undertaken; however, the extent and character of galaxy assembly bias remains a mystery. Nevertheless, characterizing and modeling galaxy assembly bias is an important step in understanding galaxy evolution and limiting any systematic effects assembly bias may pose in cosmological measurements using galaxy surveys.I will present work on modeling and constraining the effect of assembly bias in two galaxy properties: stellar mass and star-formation rate. Conditional abundance matching allows for these galaxy properties to be tied to halo formation history to a variable degree, making studies of the relative strength of assembly bias possible. Galaxy-galaxy clustering and galactic conformity, the degree to which galaxy color is correlated between neighbors, are sensitive observational measures of galaxy assembly bias. I will show how these measurements can be used to constrain galaxy assembly bias and the peril of ignoring it.

  17. Genome Sequence Databases (Overview): Sequencing and Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Lapidus, Alla L.

    2009-01-01

    From the date its role in heredity was discovered, DNA has been generating interest among scientists from different fields of knowledge: physicists have studied the three dimensional structure of the DNA molecule, biologists tried to decode the secrets of life hidden within these long molecules, and technologists invent and improve methods of DNA analysis. The analysis of the nucleotide sequence of DNA occupies a special place among the methods developed. Thanks to the variety of sequencing technologies available, the process of decoding the sequence of genomic DNA (or whole genome sequencing) has become robust and inexpensive. Meanwhile the assembly of whole genome sequences remains a challenging task. In addition to the need to assemble millions of DNA fragments of different length (from 35 bp (Solexa) to 800 bp (Sanger)), great interest in analysis of microbial communities (metagenomes) of different complexities raises new problems and pushes some new requirements for sequence assembly tools to the forefront. The genome assembly process can be divided into two steps: draft assembly and assembly improvement (finishing). Despite the fact that automatically performed assembly (or draft assembly) is capable of covering up to 98% of the genome, in most cases, it still contains incorrectly assembled reads. The error rate of the consensus sequence produced at this stage is about 1/2000 bp. A finished genome represents the genome assembly of much higher accuracy (with no gaps or incorrectly assembled areas) and quality ({approx}1 error/10,000 bp), validated through a number of computer and laboratory experiments.

  18. Dynamic pathways for viral capsid assembly

    Energy Technology Data Exchange (ETDEWEB)

    Hagan, Michael F.; Chandler, David

    2006-02-09

    We develop a class of models with which we simulate the assembly of particles into T1 capsid-like objects using Newtonian dynamics. By simulating assembly for many different values of system parameters, we vary the forces that drive assembly. For some ranges of parameters, assembly is facile, while for others, assembly is dynamically frustrated by kinetic traps corresponding to malformed or incompletely formed capsids. Our simulations sample many independent trajectories at various capsomer concentrations, allowing for statistically meaningful conclusions. Depending on subunit (i.e., capsomer) geometries, successful assembly proceeds by several mechanisms involving binding of intermediates of various sizes. We discuss the relationship between these mechanisms and experimental evaluations of capsid assembly processes.

  19. Integrated Virtual Assembly Process Planning System

    Institute of Scientific and Technical Information of China (English)

    LIU Jianhua; HOU Weiwei; HOU Weiwei; SHANG Wei; SHANG Wei; NING Ruxin; NING Ruxin

    2009-01-01

    Assembly process planning(APP) for complicated products is a time-consuming and difficult work with conventional method. Virtual assembly process planning(VAPP) provides engineers a new and efficiency way. Previous studies in VAPP are almost isolated and dispersive, and have not established a whole understanding and discussed key realization techniques of VAPP from a systemic and integrated view. The integrated virtual assembly process planning(IVAPP) system is a new virtual reality based engineering application, which offers engineers an efficient, intuitive, immersive and integrated method for assembly process planning in a virtual environment. Based on analysis the information integration requirement of VAPP, the architecture of IVAPP is proposed. Through the integrated structure, IVAPP system can realize information integration and workflow controlling. In order to model the assembly process in IVAPP, a hierarchical assembly task list(HATL) is presented, in which different assembly tasks for assembling different components are organized into a hierarchical list. A process-oriented automatic geometrical constraint recognition algorithm(AGCR) is proposed, so that geometrical constraints between components can be automatically recognized during the process of interactive assembling. At the same time, a progressive hierarchical reasoning(PHR) model is discussed. AGCR and PHR will greatly reduce the interactive workload. A discrete control node model(DCNM) for cable harness assembly planning in IVAPP is detailed. DCNM converts a cable harness into continuous flexed line segments connected by a series of section center points, and designs can realize cable harness planning through controlling those control nodes. Mechanical assemblies (such as transmission case and engine of automobile) are used to illustrate the feasibility of the proposed method and algorithms. The application of IVAPP system reveals advantages over the traditional assembly process planning method

  20. The BAGEL assembler generation library

    Science.gov (United States)

    Boyle, Peter A.

    2009-12-01

    This paper presents two coupled software packages which receive widespread use in the field of numerical simulations of Quantum Chromo-Dynamics. These consist of the BAGEL library and the BAGEL fermion sparse-matrix library, BFM. The Bagel library can generate assembly code for a number of architectures and is configurable - supporting several precision and memory pattern options to allow architecture specific optimisation. It provides high performance on the QCDOC, BlueGene/L and BlueGene/P parallel computer architectures that are popular in the field of lattice QCD. The code includes a complete conjugate gradient implementation for the Wilson and domain wall fermion actions, making it easy to use for third party codes including the Jefferson Laboratory's CHROMA, UKQCD's UKhadron, and the Riken-Brookhaven-Columbia Collaboration's CPS packages. Program summaryProgram title: Bagel Catalogue identifier: AEFE_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFE_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU Public License V2 No. of lines in distributed program, including test data, etc.: 109 576 No. of bytes in distributed program, including test data, etc.: 892 841 Distribution format: tar.gz Programming language: C++, assembler Computer: Massively parallel message passing. BlueGene/QCDOC/others. Operating system: POSIX, Linux and compatible. Has the code been vectorised or parallelized?: Yes. 16 384 processors used. Classification: 11.5 External routines: QMP, QDP++ Nature of problem: Quantum Chromo-Dynamics sparse matrix inversion for Wilson and domain wall fermion formulations. Solution method: Optimised Krylov linear solver. Unusual features: Domain specific compiler generates optimised assembly code. Running time: 1 h per matrix inversion; multi-year simulations.

  1. Parallel Assembly of LIGA Components

    Energy Technology Data Exchange (ETDEWEB)

    Christenson, T.R.; Feddema, J.T.

    1999-03-04

    In this paper, a prototype robotic workcell for the parallel assembly of LIGA components is described. A Cartesian robot is used to press 386 and 485 micron diameter pins into a LIGA substrate and then place a 3-inch diameter wafer with LIGA gears onto the pins. Upward and downward looking microscopes are used to locate holes in the LIGA substrate, pins to be pressed in the holes, and gears to be placed on the pins. This vision system can locate parts within 3 microns, while the Cartesian manipulator can place the parts within 0.4 microns.

  2. Types for DSP Assembler Programs

    DEFF Research Database (Denmark)

    Larsen, Ken

    2006-01-01

    for reuse, and a procedure that computes point-wise vector multiplication. The latter uses a common idiom of prefetching memory resulting in out-of-bounds reading from memory. I present two extensions to the baseline type system: The first extension is a simple modification of some type rules to allow out...... the requirements of a procedure. I implement a proof-of-concept type checker for both the baseline type system and the extensions. I get good performance results on a small benchmark suite of programs representative of handwritten DSP assembler code. These empirical results are encouraging and strongly suggest...

  3. Nanoengineered membrane electrode assembly interface

    Science.gov (United States)

    Song, Yujiang; Shelnutt, John A

    2013-08-06

    A membrane electrode structure suitable for use in a membrane electrode assembly (MEA) that comprises membrane-affixed metal nanoparticles whose formation is controlled by a photochemical process that controls deposition of the metal nanoparticles using a photocatalyst integrated with a polymer electrolyte membrane, such as an ionomer membrane. Impregnation of the polymer membrane with the photocatalyst prior to metal deposition greatly reduces the required amount of metal precursor in the deposition reaction solution by restricting metal reduction substantially to the formation of metal nanoparticles affixed on or near the surface of the polymer membrane with minimal formation of metallic particles not directly associated with the membrane.

  4. Algorithms for Automated DNA Assembly

    Science.gov (United States)

    2010-01-01

    Published online 23 March 2010 Nucleic Acids Research , 2010, Vol. 38, No. 8 2607–2616 doi:10.1093/nar/gkq165 The Author(s) 2010. Published by Oxford...composite part Pcon.RFP is also called an ‘intermediate part’ since it is constructed as an intermediate step in assembling the 2608 Nucleic Acids Research , 2010...in A–C. We assume part cd is already present in the part library. Nucleic Acids Research , 2010, Vol. 38, No. 8 2609 at M edical Library on S eptem ber

  5. Lab assessment of Bruce Unit 4 steam generator top-of-tubesheet cracking

    Energy Technology Data Exchange (ETDEWEB)

    Jevec, J.; Sarver, J. [Babcock and Wilcox Research Center (United States); King, P.; Yu, J. [Babcock and Wilcox Canada Ltd., Cambridge, Ontario (Canada); Sedman, K.; Durance, D. [Bruce Power, Tiverton, Ontario (Canada)

    2009-07-01

    An increasing number of significant circumferential indications were detected at the roll transition zone (RTZ) of Bruce Power Unit 4 steam generator (SG) tubing (sensitized Alloy 600) during the 2006 and 2007 Spring outages. Metallurgical examination of removed tubes found significant IGA/SCC associated with these indications. However, no circumferential indications were detected on Unit 4 SG tubing during the subsequent Fall 2007 and Spring 2008 outages. Based on a review of outage layup conditions it was theorized that the observed degradation occurs during an outage when the steam generator is drained for maintenance in combination with the presence of detrimental contaminants such as sulfur and copper. This theory was tested in the laboratory using a series of electrochemical and simulated crevice exposure tests. The oxygen/hydrazine reaction at room temperature and the resultant effect on the electrochemical potential of the sensitized Alloy 600 tubing were also studied in this program. Results from this test program are presented in this paper. The results indicate that exposure of the solutions to air tends to keep the sample in the sludge at a more reducing condition as compared to the free span tubing above the sludge resulting in a larger driving force for corrosion of the sample in the sludge. The theory that the defects in the RTZ were caused during drain-down outage conditions was shown to be plausible. (author)

  6. Nanoparticle Assemblies at Fluid Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Thomas P. [Univ. of Massachusetts, Amherst, MA (United States). Dept. of Polymer Science and Engineering

    2015-03-10

    A systematic study of the structure and dynamics of nanoparticles (NP) and NP-surfactants was performed. The ligands attached to both the NPs and NP-surfactants dictate the manner in which the nanoscopic materials assemble at fluid interfaces. Studies have shown that a single layer of the nanoscpic materials form at the interface to reduce the interactions between the two immiscible fluids. The shape of the NP is, also, important, where for spherical particles, a disordered, liquid-like monolayer forms, and, for nanorods, ordered domains at the interface is found and, if the monolayers are compressed, the orientation of the nanorods with respect to the interface can change. By associating end-functionalized polymers to the NPs assembled at the interface, NP-surfactants are formed that increase the energetic gain in segregating each NP at the interface which allows the NP-surfactants to jam at the interface when compressed. This has opened the possibility of structuring the two liquids by freezing in shape changes of the liquids.

  7. Valve stem and packing assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wordin, J.J.

    1990-12-31

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele`s pivot. The Schiele`s pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele`s pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele`s pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

  8. Anisotropic assembly and pattern formation

    Science.gov (United States)

    von Brecht, James H.; Uminsky, David T.

    2017-01-01

    We investigate the role of anisotropy in two classes of individual-based models for self-organization, collective behavior and self-assembly. We accomplish this via first-order dynamical systems of pairwise interacting particles that incorporate anisotropic interactions. At a continuum level, these models represent the natural anisotropic variants of the well-known aggregation equation. We leverage this framework to analyze the impact of anisotropic effects upon the self-assembly of co-dimension one equilibrium structures, such as micelles and vesicles. Our analytical results reveal the regularizing effect of anisotropy, and isolate the contexts in which anisotropic effects are necessary to achieve dynamical stability of co-dimension one structures. Our results therefore place theoretical limits on when anisotropic effects can be safely neglected. We also explore whether anisotropic effects suffice to induce pattern formation in such particle systems. We conclude with brief numerical studies that highlight various aspects of the models we introduce, elucidate their phase structure and partially validate the analysis we provide.

  9. Chemical reactions directed Peptide self-assembly.

    Science.gov (United States)

    Rasale, Dnyaneshwar B; Das, Apurba K

    2015-05-13

    Fabrication of self-assembled nanostructures is one of the important aspects in nanoscience and nanotechnology. The study of self-assembled soft materials remains an area of interest due to their potential applications in biomedicine. The versatile properties of soft materials can be tuned using a bottom up approach of small molecules. Peptide based self-assembly has significant impact in biology because of its unique features such as biocompatibility, straight peptide chain and the presence of different side chain functionality. These unique features explore peptides in various self-assembly process. In this review, we briefly introduce chemical reaction-mediated peptide self-assembly. Herein, we have emphasised enzymes, native chemical ligation and photochemical reactions in the exploration of peptide self-assembly.

  10. Design for Un-heterogeneous Critical Assembly

    Institute of Scientific and Technical Information of China (English)

    WANG; Fan; ZHOU; Qi

    2013-01-01

    In order to study the nuclear criticality issues in the dissolving process,a new critical assembly is designed by theoretical calculation to satisfy the heterogeneous critical experimental demands based on the existed YSR assembly(Fig.1).The experiment plans,geometry structure of the assembly,solution contents and fuel rods arrangements are determined.The parameters for each scheme are listed in Table 1.

  11. Optics assembly for high power laser tools

    Science.gov (United States)

    Fraze, Jason D.; Faircloth, Brian O.; Zediker, Mark S.

    2016-06-07

    There is provided a high power laser rotational optical assembly for use with, or in high power laser tools for performing high power laser operations. In particular, the optical assembly finds applications in performing high power laser operations on, and in, remote and difficult to access locations. The optical assembly has rotational seals and bearing configurations to avoid contamination of the laser beam path and optics.

  12. Control model for reconfigurable assembly systems

    Institute of Scientific and Technical Information of China (English)

    Yu Jianfeng; Yin Yuehong; Chen Zhaoneng

    2005-01-01

    This paper proposes knowledge based object-oriented timed colored Petri net, a modeling method for reconfigurable assembly systems. Combining knowledge and object-oriented method into timed colored Petri net, a comprehensive and powerful representation model for control of RAS is obtained. With object-oriented method the whole system can be decomposed into concrete objects explicitly, and their relationships are constructed according to the system assembly requirements. Finally, a simple assembly system modeled by the KTCOPN is presented.

  13. Tablet—next generation sequence assembly visualization

    OpenAIRE

    Milne, Iain; Bayer, Micha; Cardle, Linda; Shaw, Paul; Stephen, Gordon; Wright, Frank; Marshall, David

    2009-01-01

    Summary: Tablet is a lightweight, high-performance graphical viewer for next-generation sequence assemblies and alignments. Supporting a range of input assembly formats, Tablet provides high-quality visualizations showing data in packed or stacked views, allowing instant access and navigation to any region of interest, and whole contig overviews and data summaries. Tablet is both multi-core aware and memory efficient, allowing it to handle assemblies containing millions of reads, even on a 32...

  14. Balancing parallel assembly lines with disabled workers

    OpenAIRE

    Araújo, Felipe F. B.; Costa,Alysson M.; Miralles, Cristóbal

    2013-01-01

    We study an assembly line balancing problem that occurs in sheltered worker centers for the disabled, where workers with very different characteristics are present. We are interested in the situation in which parallel assembly lines are allowed and name the resulting problem as parallel assembly line worker assignment and balancing problem. We present a linear mixed-integer formulation and a four-stage heuristic algorithm. Computational results with a large set of instances recently proposed ...

  15. Henry Ford vs. assembly line balancing

    OpenAIRE

    Wilson, J M

    2014-01-01

    Ford’s Assembly Line at Highland Park is one of the most influential conceptualizations of a production system. New data reveal Ford’s operations were adaptable to strongly increasing and highly variable demand. These analyses show Ford’s assembly line was used differently than modern ones and their production systems were more flexible than previously recognized. Assembly line balancing theory largely ignores earlier practice. It will be shown that Ford used multiple lines flexibly to cope w...

  16. RF/Optical Demonstration: Focal Plane Assembly

    Science.gov (United States)

    Hoppe, D. J.; Chung, S.; Kovalik, J.; Gama, E.; Fernandez, M. M.

    2016-11-01

    In this article, we describe the second-generation focal plane optical assembly employed in the RF/optical demonstration at DSS-13. This assembly receives reflected light from the two mirror segments mounted on the RF primary. The focal plane assembly contains a fast steering mirror (FSM) to stabilize the focal plane spot, a pupil camera to aid in aligning the two segments, and several additional cameras for receiving the optical signal prior to as well as after the FSM loop.

  17. Metagenomic Assembly: Overview, Challenges and Applications

    Science.gov (United States)

    Ghurye, Jay S.; Cepeda-Espinoza, Victoria; Pop, Mihai

    2016-01-01

    Advances in sequencing technologies have led to the increased use of high throughput sequencing in characterizing the microbial communities associated with our bodies and our environment. Critical to the analysis of the resulting data are sequence assembly algorithms able to reconstruct genes and organisms from complex mixtures. Metagenomic assembly involves new computational challenges due to the specific characteristics of the metagenomic data. In this survey, we focus on major algorithmic approaches for genome and metagenome assembly, and discuss the new challenges and opportunities afforded by this new field. We also review several applications of metagenome assembly in addressing interesting biological problems. PMID:27698619

  18. Self-assembled nanomaterials for photoacoustic imaging.

    Science.gov (United States)

    Wang, Lei; Yang, Pei-Pei; Zhao, Xiao-Xiao; Wang, Hao

    2016-02-07

    In recent years, extensive endeavors have been paid to construct functional self-assembled nanomaterials for various applications such as catalysis, separation, energy and biomedicines. To date, different strategies have been developed for preparing nanomaterials with diversified structures and functionalities via fine tuning of self-assembled building blocks. In terms of biomedical applications, bioimaging technologies are urgently calling for high-efficient probes/contrast agents for high-performance bioimaging. Photoacoustic (PA) imaging is an emerging whole-body imaging modality offering high spatial resolution, deep penetration and high contrast in vivo. The self-assembled nanomaterials show high stability in vivo, specific tolerance to sterilization and prolonged half-life stability and desirable targeting properties, which is a kind of promising PA contrast agents for biomedical imaging. Herein, we focus on summarizing recent advances in smart self-assembled nanomaterials with NIR absorption as PA contrast agents for biomedical imaging. According to the preparation strategy of the contrast agents, the self-assembled nanomaterials are categorized into two groups, i.e., the ex situ and in situ self-assembled nanomaterials. The driving forces, assembly modes and regulation of PA properties of self-assembled nanomaterials and their applications for long-term imaging, enzyme activity detection and aggregation-induced retention (AIR) effect for diagnosis and therapy are emphasized. Finally, we conclude with an outlook towards future developments of self-assembled nanomaterials for PA imaging.

  19. Ultrasound transducer assembly and method for manufacturing an ultrasound transducer assembly

    NARCIS (Netherlands)

    Dekker, R.; Henneken, V.A.; Louwerse, M.C.; Raganato, M.F.

    2015-01-01

    The present invention relates to an ultrasound transducer assembly (10), in particular for intravascular ultrasound systems. The ultrasound transducer assembly comprises at least one silicon substrate element (30) including an ultrasound transducer element (14) for emitting and receiving ultrasound

  20. Laminins in basement membrane assembly.

    Science.gov (United States)

    Hohenester, Erhard; Yurchenco, Peter D

    2013-01-01

    The heterotrimeric laminins are a defining component of all basement membranes and self-assemble into a cell-associated network. The three short arms of the cross-shaped laminin molecule form the network nodes, with a strict requirement for one α, one β and one γ arm. The globular domain at the end of the long arm binds to cellular receptors, including integrins, α-dystroglycan, heparan sulfates and sulfated glycolipids. Collateral anchorage of the laminin network is provided by the proteoglycans perlecan and agrin. A second network is then formed by type IV collagen, which interacts with the laminin network through the heparan sulfate chains of perlecan and agrin and additional linkage by nidogen. This maturation of basement membranes becomes essential at later stages of embryo development.

  1. Photonic-powered cable assembly

    Science.gov (United States)

    Sanderson, Stephen N.; Appel, Titus James; Wrye, IV, Walter C.

    2013-01-22

    A photonic-cable assembly includes a power source cable connector ("PSCC") coupled to a power receive cable connector ("PRCC") via a fiber cable. The PSCC electrically connects to a first electronic device and houses a photonic power source and an optical data transmitter. The fiber cable includes an optical transmit data path coupled to the optical data transmitter, an optical power path coupled to the photonic power source, and an optical feedback path coupled to provide feedback control to the photonic power source. The PRCC electrically connects to a second electronic device and houses an optical data receiver coupled to the optical transmit data path, a feedback controller coupled to the optical feedback path to control the photonic power source, and a photonic power converter coupled to the optical power path to convert photonic energy received over the optical power path to electrical energy to power components of the PRCC.

  2. Fellows Celebrated at Joint Assembly

    Science.gov (United States)

    2009-06-01

    The 2009 AGU Fellows were presented at the recent Joint Assembly in Toronto, Ontario, Canada. At a formal ceremony on 26 May 2009, AGU President Timothy L. Grove introduced each Fellow and read a brief statement of the achievements for which each had been selected. The presentations were followed by a reception for meeting attendees and a banquet at which family members and close colleagues further feted the honorees. AGU Fellows are scientists who have attained “acknowledged eminence in the geophysical sciences.” Election to AGU Fellowship is a very high recognition by one's peers. The number of Fellows elected may not exceed 0.1% of the membership in any given year.

  3. Self assembly of interlocked architectures

    CERN Document Server

    Schergna, S

    2002-01-01

    An area of great interest is the synthesis and characterisation of molecules possessing moving parts, with the goal that they can act as 'molecular machine' carrying out tasks that molecules with fixed conventional architectures cannot do. Rotaxanes and catenanes (mechanically interlocked architectures) represent one approach toward achieving these aims as their component wheels and / or threads are connected together but can still move, in certain, controlled directions. This thesis focused on the study of structural rigidity and the preorganisation of thread binding sites as factors of major influence on template efficiency in the synthesis of hydrogen bond assembled supramolecular structures (rotaxanes and catenanes). Chapter One gives a brief outline of the common synthetic approaches to interlocked architectures (catenanes and rotaxanes) that are now being developed to address the problems outlined above. Chapter Two and Chapter Three concerns the synthesis of novel amide-based rotaxanes containing vario...

  4. Directed actin assembly and motility.

    Science.gov (United States)

    Boujemaa-Paterski, Rajaa; Galland, Rémi; Suarez, Cristian; Guérin, Christophe; Théry, Manuel; Blanchoin, Laurent

    2014-01-01

    The actin cytoskeleton is a key component of the cellular architecture. However, understanding actin organization and dynamics in vivo is a complex challenge. Reconstitution of actin structures in vitro, in simplified media, allows one to pinpoint the cellular biochemical components and their molecular interactions underlying the architecture and dynamics of the actin network. Previously, little was known about the extent to which geometrical constraints influence the dynamic ultrastructure of these networks. Therefore, in order to study the balance between biochemical and geometrical control of complex actin organization, we used the innovative methodologies of UV and laser patterning to design a wide repertoire of nucleation geometries from which we assembled branched actin networks. Using these methods, we were able to reconstitute complex actin network organizations, closely related to cellular architecture, to precisely direct and control their 3D connections. This methodology mimics the actin networks encountered in cells and can serve in the fabrication of innovative bioinspired systems.

  5. Reconfigurable optical assembly of nanostructures

    Science.gov (United States)

    Montelongo, Yunuen; Yetisen, Ali K.; Butt, Haider; Yun, Seok-Hyun

    2016-06-01

    Arrangements of nanostructures in well-defined patterns are the basis of photonic crystals, metamaterials and holograms. Furthermore, rewritable optical materials can be achieved by dynamically manipulating nanoassemblies. Here we demonstrate a mechanism to configure plasmonic nanoparticles (NPs) in polymer media using nanosecond laser pulses. The mechanism relies on optical forces produced by the interference of laser beams, which allow NPs to migrate to lower-energy configurations. The resulting NP arrangements are stable without any external energy source, but erasable and rewritable by additional recording pulses. We demonstrate reconfigurable optical elements including multilayer Bragg diffraction gratings, volumetric photonic crystals and lenses, as well as dynamic holograms of three-dimensional virtual objects. We aim to expand the applications of optical forces, which have been mostly restricted to optical tweezers. Holographic assemblies of nanoparticles will allow a new generation of programmable composites for tunable metamaterials, data storage devices, sensors and displays.

  6. Nanocrystal assembly for tandem catalysis

    Science.gov (United States)

    Yang, Peidong; Somorjai, Gabor; Yamada, Yusuke; Tsung, Chia-Kuang; Huang, Wenyu

    2014-10-14

    The present invention provides a nanocrystal tandem catalyst comprising at least two metal-metal oxide interfaces for the catalysis of sequential reactions. One embodiment utilizes a nanocrystal bilayer structure formed by assembling sub-10 nm platinum and cerium oxide nanocube monolayers on a silica substrate. The two distinct metal-metal oxide interfaces, CeO.sub.2--Pt and Pt--SiO.sub.2, can be used to catalyze two distinct sequential reactions. The CeO.sub.2--Pt interface catalyzed methanol decomposition to produce CO and H.sub.2, which were then subsequently used for ethylene hydroformylation catalyzed by the nearby Pt--SiO.sub.2 interface. Consequently, propanal was selectively produced on this nanocrystal bilayer tandem catalyst.

  7. Low inductance power electronics assembly

    Science.gov (United States)

    Herron, Nicholas Hayden; Mann, Brooks S.; Korich, Mark D.; Chou, Cindy; Tang, David; Carlson, Douglas S.; Barry, Alan L.

    2012-10-02

    A power electronics assembly is provided. A first support member includes a first plurality of conductors. A first plurality of power switching devices are coupled to the first support member. A first capacitor is coupled to the first support member. A second support member includes a second plurality of conductors. A second plurality of power switching devices are coupled to the second support member. A second capacitor is coupled to the second support member. The first and second pluralities of conductors, the first and second pluralities of power switching devices, and the first and second capacitors are electrically connected such that the first plurality of power switching devices is connected in parallel with the first capacitor and the second capacitor and the second plurality of power switching devices is connected in parallel with the second capacitor and the first capacitor.

  8. High temperature control rod assembly

    Energy Technology Data Exchange (ETDEWEB)

    Vollman, Russell E. (Solana Beach, CA)

    1991-01-01

    A high temperature nuclear control rod assembly comprises a plurality of substantially cylindrical segments flexibly joined together in succession by ball joints. The segments are made of a high temperature graphite or carbon-carbon composite. The segment includes a hollow cylindrical sleeve which has an opening for receiving neutron-absorbing material in the form of pellets or compacted rings. The sleeve has a threaded sleeve bore and outer threaded surface. A cylindrical support post has a threaded shaft at one end which is threadably engaged with the sleeve bore to rigidly couple the support post to the sleeve. The other end of the post is formed with a ball portion. A hollow cylindrical collar has an inner threaded surface engageable with the outer threaded surface of the sleeve to rigidly couple the collar to the sleeve. the collar also has a socket portion which cooperates with the ball portion to flexibly connect segments together to form a ball and socket-type joint. In another embodiment, the segment comprises a support member which has a threaded shaft portion and a ball surface portion. The threaded shaft portion is engageable with an inner threaded surface of a ring for rigidly coupling the support member to the ring. The ring in turn has an outer surface at one end which is threadably engageably with a hollow cylindrical sleeve. The other end of the sleeve is formed with a socket portion for engagement with a ball portion of the support member. In yet another embodiment, a secondary rod is slidably inserted in a hollow channel through the center of the segment to provide additional strength. A method for controlling a nuclear reactor utilizing the control rod assembly is also included.

  9. Valve stem and packing assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wordin, J.J.

    1991-09-03

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents over tightening of the retaining nut and the resulting excessive friction between stem and stem packing. 2 figures.

  10. Valve stem and packing assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wordin, John J. (Bingham County, ID)

    1991-01-01

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

  11. Valve stem and packing assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wordin, J.J.

    1990-01-01

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

  12. Research on Self-Assembling Quantum Dots.

    Science.gov (United States)

    1995-10-30

    0K. in a second phase of this contract we turned our efforts to the fabrication and studies of self assembled quantum dots . We first demonstrated a...method for producing InAs-GasAs self assembled quantum dots (SAD) using MBE. (AN)

  13. Uracil Excision for Assembly of Complex Pathways

    DEFF Research Database (Denmark)

    Cavaleiro, Mafalda; Nielsen, Morten Thrane; Kim, Se Hyeuk

    2015-01-01

    Despite decreasing prices on synthetic DNA constructs, higher-order assembly of PCR-generated DNA continues to be an important exercise in molecular and synthetic biology. Simplicity and robustness are attractive features met by the uracil excision DNA assembly method, which is one of the most in...

  14. Fibril assembly in whey protein mixtures

    NARCIS (Netherlands)

    Bolder, S.G.

    2007-01-01

    The objective of this thesis was to study fibril assembly in mixtures of whey proteins. The effect of the composition of the protein mixture on the structures and the resulting phase behaviour was investigated. The current work has shown that beta-lactoglobulin is responsible for the fibril assembly

  15. MTI Focal Plane Assembly Design and Performance

    Energy Technology Data Exchange (ETDEWEB)

    Ballard, M.; Rienstra, J.L.

    1999-06-17

    The focal plane assembly for the Multispectral Thermal Imager (MTI) consists of sensor chip assemblies, optical filters, and a vacuum enclosure. Sensor chip assemblies, composed of linear detector arrays and readout integrated circuits, provide spatial resolution in the cross-track direction for the pushbroom imager. Optical filters define 15 spectral bands in a range from 0.45 {micro}m to 10.7 {micro}m. All the detector arrays are mounted on a single focal plane and are designed to operate at 75 K. Three pairs of sensor chip assemblies (SCAs) are required to provide cross-track coverage in all 15 spectral bands. Each pair of SCAs includes detector arrays made from silicon, iridium antimonide, and mercury cadmium telluride. Read out integrated circuits multiplex the signals from the detectors to 18 separate video channels. Optical filter assemblies defining the spectral bands are mounted over the linear detector arrays. Each filter assembly consists of several filter strips bonded together side-by-side. The MTI focal plane assembly has been integrated with the rest of the payload and has undergone detailed testing and calibration. This paper includes representative test data for the various spectral bands and the overall performance of the focal plane assembly.

  16. Aerodynamic seal assemblies for turbo-machinery

    Energy Technology Data Exchange (ETDEWEB)

    Bidkar, Rahul Anil; Wolfe, Christopher; Fang, Biao

    2015-09-29

    The present application provides an aerodynamic seal assembly for use with a turbo-machine. The aerodynamic seal assembly may include a number of springs, a shoe connected to the springs, and a secondary seal positioned about the springs and the shoe.

  17. CT Performance Evaluation Using Multi Material Assemblies

    DEFF Research Database (Denmark)

    Stolfi, Alessandro; De Chiffre, Leonardo

    2015-01-01

    This paper concerns an investigation of the accuracy of Computed Tomography measurements using multi-material assemblies. In this study, assemblies involving similar densities for elementary parts were considered. The investigation includes dimensional and geometrical measurements of two 10 mm hi...

  18. Assembly of the CMS hadronic calorimeter

    CERN Document Server

    Maximilien Brice

    2004-01-01

    The hadronic calorimeter is assembled on the end-cap of the CMS detector in the assembly hall. Hadronic calorimeters measure the energy of particles that interact via the strong force, called hadrons. The detectors are made in a sandwich-like structure where these scintillator tiles are placed between metal sheets.

  19. Preliminary High-Throughput Metagenome Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Dusheyko, Serge; Furman, Craig; Pangilinan, Jasmyn; Shapiro, Harris; Tu, Hank

    2007-03-26

    Metagenome data sets present a qualitatively different assembly problem than traditional single-organism whole-genome shotgun (WGS) assembly. The unique aspects of such projects include the presence of a potentially large number of distinct organisms and their representation in the data set at widely different fractions. In addition, multiple closely related strains could be present, which would be difficult to assemble separately. Failure to take these issues into account can result in poor assemblies that either jumble together different strains or which fail to yield useful results. The DOE Joint Genome Institute has sequenced a number of metagenomic projects and plans to considerably increase this number in the coming year. As a result, the JGI has a need for high-throughput tools and techniques for handling metagenome projects. We present the techniques developed to handle metagenome assemblies in a high-throughput environment. This includes a streamlined assembly wrapper, based on the JGI?s in-house WGS assembler, Jazz. It also includes the selection of sensible defaults targeted for metagenome data sets, as well as quality control automation for cleaning up the raw results. While analysis is ongoing, we will discuss preliminary assessments of the quality of the assembly results (http://fames.jgi-psf.org).

  20. ATLAS: End-cap Toroid assembly

    CERN Multimedia

    2006-01-01

    In building 191 and building 180- assembly of this massive piece.To reach the top of the end-cap the cranes has to be used and during the assembly you can see welding and hear many tools running background.

  1. Self-assembled nanogaps for molecular electronics

    DEFF Research Database (Denmark)

    Tang, Qingxin; Tong, Yanhong; Jain, Titoo

    2009-01-01

    A nanogap for molecular devices was realized using solution-based self-assembly. Gold nanorods were assembled to gold nanoparticle-coated conducting SnO2:Sb nanowires via thiol end-capped oligo(phenylenevinylene)s (OPVs). The molecular gap was easily created by the rigid molecule itself during se...

  2. Cable Harness Assembly Planning in Virtual Environment

    Institute of Scientific and Technical Information of China (English)

    LIU Jianhua; NING Ruxin; BAI Shuqing; WANG Bile

    2006-01-01

    Based on the analysis of characteristic of cable harness planning in virtual environment, a discrete control node modeling (DCNM) method of cable harness in virtual environment and the cable harness assembly routing technique based on it are proposed. DCNM converts a cable harness into continuous flexed line segments connected by a series of section center points, and the design can realize cable harness planning through controlling those control nodes. This method of cable harness routing in the virtual environment breaks the status that virtual assembly process planning is just suitable for the rigid components at present, and impulse the virtual assembly process planning to be more practical. Relation algorithms have been verified in a self-developed system named virtual cable harness assembly planning (VCHAP) system, and this VCHAP system has been applied in assembly process planning of aerospace-related products.

  3. Clean Industrial Room for Drift Tube Assembling

    CERN Document Server

    Glonti, GL; Evtoukhovitch, P G; Kroa, G; Manz, A; Potrap, I N; Rihter, P; Stoletov, G D; Tskhadadze, E G; Chepurnov, V F; Chirkov, A V; Shelkov, G A

    2001-01-01

    Description of a clean industrial room for assembly of drift tubes for the muon spectrometer of the ATLAS experiment is presented. High quality specifications on the detectors to be produced demanded creation of a workplace with stable temperature and humidity, as well as minimum quantity of dust in the room. Checking of parameters of intra-room air during long period of continuous work has been confirmed correctness of the designed characteristics of the climatic system installed in the clean room. The room large volum (\\sim 190 m^3), the powerful and flexible climatic system, and simplicity of service allow assembling of detectors with length up to 5 m. Subsequent checking of functionality of the assembled detectors has shown high quality of assembling (the amount of rejected tubes does not exceed 2 %). It demonstrates conformity to the assembling quality requirements for mass production of drift chambers for the muon spectrometer.

  4. Specific genomic cues regulate Cajal body assembly.

    Science.gov (United States)

    Sawyer, Iain A; Hager, Gordon L; Dundr, Miroslav

    2016-10-07

    The assembly of specialized sub-nuclear microenvironments known as nuclear bodies (NBs) is important for promoting efficient nuclear function. In particular, the Cajal body (CB), a prominent NB that facilitates spliceosomal snRNP biogenesis, assembles in response to genomic cues. Here, we detail the factors that regulate CB assembly and structural maintenance. These include the importance of transcription at nucleating gene loci, the grouping of these genes on human chromosomes 1, 6 and 17, as well as cell cycle and biochemical regulation of CB protein function. We also speculate on the correlation between CB formation and RNA splicing levels in neurons and cancer. The timing and location of these specific molecular events is critical to CB assembly and its contribution to genome function. However, further work is required to explore the emerging biophysical characteristics of CB assembly and the impact upon subsequent genome reorganization.

  5. Quality Assessment of Domesticated Animal Genome Assemblies.

    Science.gov (United States)

    Seemann, Stefan E; Anthon, Christian; Palasca, Oana; Gorodkin, Jan

    2015-01-01

    The era of high-throughput sequencing has made it relatively simple to sequence genomes and transcriptomes of individuals from many species. In order to analyze the resulting sequencing data, high-quality reference genome assemblies are required. However, this is still a major challenge, and many domesticated animal genomes still need to be sequenced deeper in order to produce high-quality assemblies. In the meanwhile, ironically, the extent to which RNAseq and other next-generation data is produced frequently far exceeds that of the genomic sequence. Furthermore, basic comparative analysis is often affected by the lack of genomic sequence. Herein, we quantify the quality of the genome assemblies of 20 domesticated animals and related species by assessing a range of measurable parameters, and we show that there is a positive correlation between the fraction of mappable reads from RNAseq data and genome assembly quality. We rank the genomes by their assembly quality and discuss the implications for genotype analyses.

  6. Human Contamination in Public Genome Assemblies

    Science.gov (United States)

    Kryukov, Kirill; Imanishi, Tadashi

    2016-01-01

    Contamination in genome assembly can lead to wrong or confusing results when using such genome as reference in sequence comparison. Although bacterial contamination is well known, the problem of human-originated contamination received little attention. In this study we surveyed 45,735 available genome assemblies for evidence of human contamination. We used lineage specificity to distinguish between contamination and conservation. We found that 154 genome assemblies contain fragments that with high confidence originate as contamination from human DNA. Majority of contaminating human sequences were present in the reference human genome assembly for over a decade. We recommend that existing contaminated genomes should be revised to remove contaminated sequence, and that new assemblies should be thoroughly checked for presence of human DNA before submitting them to public databases. PMID:27611326

  7. Structural Assembly Demonstration Experiment (SADE) experiment design

    Science.gov (United States)

    Akin, D. L.; Bowden, M. L.

    1982-03-01

    The Structural Assembly Demonstration Experiment concept is to erect a hybrid deployed/assembled structure as an early space experiment in large space structures technology. The basic objectives can be broken down into three generic areas: (1) by performing assembly tasks both in space and in neutral buoyancy simulation, a mathematical basis will be found for the validity conditions of neutral buoyancy, thus enhancing the utility of water as a medium for simulation of weightlessness; (2) a data base will be established describing the capabilities and limitations of EVA crewmembers, including effects of such things as hardware size and crew restraints; and (3) experience of the M.I.T. Space Systems Lab in neutral buoyancy simulation of large space structures assembly indicates that the assembly procedure may create the largest loads that a structure will experience during its lifetime. Data obtained from the experiment will help establish an accurate loading model to aid designers of future space structures.

  8. Liquid-liquid interfacial nanoparticle assemblies

    Science.gov (United States)

    Emrick, Todd S.; Russell, Thomas P.; Dinsmore, Anthony; Skaff, Habib; Lin, Yao

    2008-12-30

    Self-assembly of nanoparticles at the interface between two fluids, and methods to control such self-assembly process, e.g., the surface density of particles assembling at the interface; to utilize the assembled nanoparticles and their ligands in fabrication of capsules, where the elastic properties of the capsules can be varied from soft to tough; to develop capsules with well-defined porosities for ultimate use as delivery systems; and to develop chemistries whereby multiple ligands or ligands with multiple functionalities can be attached to the nanoparticles to promote the interfacial segregation and assembly of the nanoparticles. Certain embodiments use cadmium selenide (CdSe) nanoparticles, since the photoluminescence of the particles provides a convenient means by which the spatial location and organization of the particles can be probed. However, the systems and methodologies presented here are general and can, with suitable modification of the chemistries, be adapted to any type of nanoparticle.

  9. Hydrodynamically driven colloidal assembly in dip coating.

    Science.gov (United States)

    Colosqui, Carlos E; Morris, Jeffrey F; Stone, Howard A

    2013-05-01

    We study the hydrodynamics of dip coating from a suspension and report a mechanism for colloidal assembly and pattern formation on smooth substrates. Below a critical withdrawal speed where the coating film is thinner than the particle diameter, capillary forces induced by deformation of the free surface prevent the convective transport of single particles through the meniscus beneath the film. Capillary-induced forces are balanced by hydrodynamic drag only after a minimum number of particles assemble within the meniscus. The particle assembly can thus enter the thin film where it moves at nearly the withdrawal speed and rapidly separates from the next assembly. The interplay between hydrodynamic and capillary forces produces periodic and regular structures below a critical ratio Ca(2/3)/sqrt[Bo] particles in suspension. The hydrodynamically driven assembly documented here is consistent with stripe pattern formations observed experimentally in dip coating.

  10. Innovation in Layer-by-Layer Assembly.

    Science.gov (United States)

    Richardson, Joseph J; Cui, Jiwei; Björnmalm, Mattias; Braunger, Julia A; Ejima, Hirotaka; Caruso, Frank

    2016-12-14

    Methods for depositing thin films are important in generating functional materials for diverse applications in a wide variety of fields. Over the last half-century, the layer-by-layer assembly of nanoscale films has received intense and growing interest. This has been fueled by innovation in the available materials and assembly technologies, as well as the film-characterization techniques. In this Review, we explore, discuss, and detail innovation in layer-by-layer assembly in terms of past and present developments, and we highlight how these might guide future advances. A particular focus is on conventional and early developments that have only recently regained interest in the layer-by-layer assembly field. We then review unconventional assemblies and approaches that have been gaining popularity, which include inorganic/organic hybrid materials, cells and tissues, and the use of stereocomplexation, patterning, and dip-pen lithography, to name a few. A relatively recent development is the use of layer-by-layer assembly materials and techniques to assemble films in a single continuous step. We name this "quasi"-layer-by-layer assembly and discuss the impacts and innovations surrounding this approach. Finally, the application of characterization methods to monitor and evaluate layer-by-layer assembly is discussed, as innovation in this area is often overlooked but is essential for development of the field. While we intend for this Review to be easily accessible and act as a guide to researchers new to layer-by-layer assembly, we also believe it will provide insight to current researchers in the field and help guide future developments and innovation.

  11. High temperature control rod assembly

    Energy Technology Data Exchange (ETDEWEB)

    Vollman, R.E.

    1991-12-24

    This patent describes a control rod assembly for use in nuclear reactor control. It comprises segments, each the segment being made of a graphite composite material, each the segment having a chamber for containing neutron-absorbing material, wherein the chamber compromises a hollow cylindrical sleeve having a first end formed with an opening for receiving the neutron-absorbing material, and having a second end formed with a sleeve bore and an outer sleeve surface; a cylindrical weight-bearing support post positioned substantially centrally of the sleeve, the support post having a first end formed as a ball surface portion and a second end formed as a ball surface portion and a second end formed as a shaft, the shaft being engageable with the sleeve bore for rigidly coupling the support post axially within the hollow sleeve, a hollow cylindrical collar having a socket lip portion correspondingly shaped to receive the ball surface portion of an adjacent support post, and having an inner surface for engaging the outer sleeve surface on the second end of the sleeve to rigidly couple the collar to the sleeve.

  12. Light-structured colloidal assemblies

    Science.gov (United States)

    Aubret, Antoine; Mena, Youssef; Ramananarivo, Sophie; Sacanna, Stefano; Palacci, Jeremie; Palacci lab Team; Sacanna lab Team

    2016-11-01

    Self-propelled particles (SPP) are a key tool since they are of relative simplicity as compared to biological micro-entities and provide a higher level of control. They can convert an energy source into motion and work, and exhibit surprising non-equilibrium behavior. In our work, we focus on the manipulation of colloids using light. We exploit osmotic and phoretic effects to act on single and ensemble of colloids. The key mechanism relies on the photocatalytic decomposition of hydrogen peroxide using hematite, which triggers the motion of colloids around it when illuminated. We use hematite particles and particles with photocatalytic inclusions (i.e. SPP). We first show that the interactions between hematite and colloidal tracers can be tuned by adjusting the chemical environment. Furthermore, we report a phototaxic behavior (migration in light gradient) of the particles. From this, we explore the effect of spatio-temporal modulation of the light to control the motion of colloids at the single particle level, and to generate self-assembled colloidal structures through time and space. The so-formed structures are maintained by phoretic and hydrodynamic forces resulting from the motion of each particles. Ultimately, a dynamic light modulation may be a route for the creation of active colloidal motion on a collective scale through the synchronization of the individual motions of SPP. This work is supported by NSF CAREER DMR 1554724.

  13. Theory of meiotic spindle assembly

    Science.gov (United States)

    Furthauer, Sebastian; Foster, Peter; Needleman, Daniel; Shelley, Michael

    2016-11-01

    The meiotic spindle is a biological structure that self assembles from the intracellular medium to separate chromosomes during meiosis. It consists of filamentous microtubule (MT) proteins that interact through the fluid in which they are suspended and via the associated molecules that orchestrate their behavior. We aim to understand how the interplay between fluid medium, MTs, and regulatory proteins allows this material to self-organize into the spindle's highly stereotyped shape. To this end we develop a continuum model that treats the spindle as an active liquid crystal with MT turnover. In this active material, molecular motors, such as dyneins which collect MT minus ends and kinesins which slide MTs past each other, generate active fluid and material stresses. Moreover nucleator proteins that are advected with and transported along MTs control the nucleation and depolymerization of MTs. This theory captures the growth process of meiotic spindles, their shapes, and the essential features of many perturbation experiments. It thus provides a framework to think about the physics of this complex biological suspension.

  14. Mechanical Self-Assembly Science and Applications

    CERN Document Server

    2013-01-01

    Mechanical Self-Assembly: Science and Applications introduces a novel category of self-assembly driven by mechanical forces. This book discusses self-assembly in various types of small material structures including thin films, surfaces, and micro- and nano-wires, as well as the practice's potential application in micro and nanoelectronics, MEMS/NEMS, and biomedical engineering. The mechanical self-assembly process is inherently quick, simple, and cost-effective, as well as accessible to a large number of materials, such as curved surfaces for forming three-dimensional small structures. Mechanical self-assembly is complementary to, and sometimes offer advantages over, the traditional micro- and nano-fabrication. This book also: Presents a highly original aspect of the science of self-assembly Describes the novel methods of mechanical assembly used to fabricate a variety of new three-dimensional material structures in simple and cost-effective ways Provides simple insights to a number of biological systems and ...

  15. Self and directed assembly: people and molecules

    Directory of Open Access Journals (Sweden)

    Tony D. James

    2016-03-01

    Full Text Available Self-assembly and directed-assembly are two very important aspects of supramolecular chemistry. As a young postgraduate student working in Canada with Tom Fyles my introduction to Supramolecular Chemistry was through the self-assembly of phospholipid membranes to form vesicles for which we were developing unimolecular and self-assembling transporter molecules. The next stage of my development as a scientist was in Japan with Seiji Shinkai where in a “Eureka” moment, the boronic acid templating unit (directed-assembly of Wulff was combined with photoinduced electron transfer systems pioneered by De Silva. The result was a turn-on fluorescence sensor for saccharides; this simple result has continued to fuel my research to the present day. Throughout my career as well as assembling molecules, I have enjoyed bringing together researchers in order to develop collaborative networks. This is where molecules meet people resulting in assemblies worth more than the individual “molecule” or “researcher”. My role in developing networks with Japan was rewarded by the award of a Daiwa-Adrian Prize in 2013 and I was recently rewarded for developing networks with China with an Inaugural CASE Prize in 2015.

  16. Assembly design system based on engineering connection

    Science.gov (United States)

    Yin, Wensheng

    2016-12-01

    An assembly design system is an important part of computer-aided design systems, which are important tools for realizing product concept design. The traditional assembly design system does not record the connection information of production on the engineering layer; consequently, the upstream design idea cannot be fully used in the downstream design. An assembly design model based on the relationship of engineering connection is presented. In this model, all nodes are divided into two categories: The component and the connection. Moreover, the product is constructed on the basis of the connection relationship of the components. The model is an And/Or graph and has the ability to record all assembly schemes. This model records only the connection information that has engineering application value in the product design. In addition, this model can significantly reduce the number of combinations, and is very favorable for the assembly sequence planning in the downstream. The system contains a connection knowledge system that can be mapped to the connection node, and the connection knowledge obtained in practice can be returned to the knowledge system. Finally, VC++ 6.0 is used to develop a prototype system called Connect-based Assembly Planning (CAP). The relationship between the CAP system and the commercial assembly design system is also established.

  17. Constraints on Assembly Bias from Galaxy Clustering

    CERN Document Server

    Zentner, Andrew R; Bosch, Frank C van den; Lange, Johannes U; Villarreal, Antonio

    2016-01-01

    We constrain the newly-introduced decorated Halo Occupation Distribution (HOD) model using SDSS DR7 measurements of projected galaxy clustering or r-band luminosity threshold samples. The decorated HOD is a model for the galaxy-halo connection that augments the HOD by allowing for the possibility of galaxy assembly bias: galaxy luminosity may be correlated with dark matter halo properties besides mass, Mvir. We demonstrate that it is not possible to rule out galaxy assembly bias using DR7 measurements of galaxy clustering alone. Moreover, galaxy samples with Mr < -20 and Mr < -20.5 favor strong central galaxy assembly bias. These samples prefer scenarios in which high-concentration are more likely to host a central galaxy relative to low-concentration halos of the same mass. We exclude zero assembly bias with high significance for these samples. Satellite galaxy assembly bias is significant for the faintest sample, Mr < -19. We find no evidence for assembly bias in the Mr < -21 sample. Assembly bi...

  18. Directed Self-Assembly of Nanodispersions

    Energy Technology Data Exchange (ETDEWEB)

    Furst, Eric M [University of Delaware

    2013-11-15

    Directed self-assembly promises to be the technologically and economically optimal approach to industrial-scale nanotechnology, and will enable the realization of inexpensive, reproducible and active nanostructured materials with tailored photonic, transport and mechanical properties. These new nanomaterials will play a critical role in meeting the 21st century grand challenges of the US, including energy diversity and sustainability, national security and economic competitiveness. The goal of this work was to develop and fundamentally validate methods of directed selfassembly of nanomaterials and nanodispersion processing. The specific aims were: 1. Nanocolloid self-assembly and interactions in AC electric fields. In an effort to reduce the particle sizes used in AC electric field self-assembly to lengthscales, we propose detailed characterizations of field-driven structures and studies of the fundamental underlying particle interactions. We will utilize microscopy and light scattering to assess order-disorder transitions and self-assembled structures under a variety of field and physicochemical conditions. Optical trapping will be used to measure particle interactions. These experiments will be synergetic with calculations of the particle polarizability, enabling us to both validate interactions and predict the order-disorder transition for nanocolloids. 2. Assembly of anisotropic nanocolloids. Particle shape has profound effects on structure and flow behavior of dispersions, and greatly complicates their processing and self-assembly. The methods developed to study the self-assembled structures and underlying particle interactions for dispersions of isotropic nanocolloids will be extended to systems composed of anisotropic particles. This report reviews several key advances that have been made during this project, including, (1) advances in the measurement of particle polarization mechanisms underlying field-directed self-assembly, and (2) progress in the

  19. Object-Oriented Modeling of Virtual Assembly Process

    Institute of Scientific and Technical Information of China (English)

    ZhengTaixiong; HeYulin; 等

    2002-01-01

    Virtual assembly is a Virtual Reality(VR) based engineering application which allows engineers to evaluate,analyze,and plan the assembly of mechanical systems,To model the virtual assembly process,new methodology must be applied.Based on the idea that the virtual assembly system is an event driven system,the interactive behavior and information model is proposed to describe the dynamic process of virtual assembly.Definition of the objectoriented model of virtual assembly is put forward.

  20. Aerobrake assembly with minimum Space Station accommodation

    Science.gov (United States)

    Katzberg, Steven J.; Butler, David H.; Doggett, William R.; Russell, James W.; Hurban, Theresa

    1991-01-01

    The minimum Space Station Freedom accommodations required for initial assembly, repair, and refurbishment of the Lunar aerobrake were investigated. Baseline Space Station Freedom support services were assumed, as well as reasonable earth-to-orbit possibilities. A set of three aerobrake configurations representative of the major themes in aerobraking were developed. Structural assembly concepts, along with on-orbit assembly and refurbishment scenarios were created. The scenarios were exercised to identify required Space Station Freedom accommodations. Finally, important areas for follow-on study were also identified.

  1. Analysis of Human Communication during Assembly Tasks.

    Science.gov (United States)

    1986-06-01

    AD-A7l 43 ANALYSIS OF HUMAN COMMUNICATION DURING ASSEMBLY TASKS in1(U) CRNEGIE-MELLO UNIY PITTSBURGH PA ROBOTICS INST UNCLSSIIEDK S BARBER ET AL...ao I Dur~~~~IngAbcbyTs; 7c .S:in i lSAo .0. Analysis of Human Communication During Assembly Tasks K. Suzanne Barber and Gerald J. Agin CMU-RI-TR-86-1...TYPE or REPORT & PE-Rioo CevCZaz Analysis of Human Communication During Assembly Inlterim Tasks I . PERFORMING 00RG. REPORT NUMBER 1. £UT~oOR~e) IL

  2. Recent development of peptide self-assembly

    Institute of Scientific and Technical Information of China (English)

    Xiubo Zhao; Fang Pan; Jian R. Lu

    2008-01-01

    Amino acids are the building blocks to build peptides and proteins. Recent development in peptide synthesis has however enabled us to mimic this natural process by preparing various long and short peptides possessing different conformations and biological functions. The self-assembly of short designed peptides into molecular nanostructures is becoming a growing interest in nanobiotechnology. Self-assembled peptides exhibit several attractive features for applications in tissue regeneration, drug delivery, biological surface engineering as well as in food science, cosmetic industry and antibiotics. The aim of this review is to introduce the readers to a number of representative studies on peptide self-assembly.

  3. Irradiated MTR fuel assemblies sipping test

    Energy Technology Data Exchange (ETDEWEB)

    Perrotta, J.A.; Terremoto, Luis A.A.; Zeituni, Carlos A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Div. de Engenharia do Nucleo

    1997-10-01

    This paper describes the procedure and methodology used to perform sipping test with the IEA-R1 fuel assemblies at the storage pool, and presents the results obtained for Cs-137 sipping water activity for each fuel assembly analyzed. Discussion is made correlating corrosion pits to the activity values measured. A Cs-137 leaking rate is determined which can be compared to the criteria established for canning spent fuel assemblies inside the pool of for shipment abroad. 3 refs., 13 figs., 1 tab.

  4. Mudular Product Families and Assembly Systems

    DEFF Research Database (Denmark)

    Thyssen, Jesper

    of modular product families and the interacting assembly system.   The thesis reviews extant theory and provides various classifications and discussions guided by the overall theme of product modularity and assembly systems. The empirical system analysis, based upon a longitudinal single case study......, articulates a system model incorporating both structural and performance elements. The extensive and detailed case analysis provides the necessary insight into the specific variables associated with the complex configuration of modular products and assembly systems.   Based upon the system model a number...

  5. Seismic response of nuclear fuel assembly

    Directory of Open Access Journals (Sweden)

    Hlaváč Z.

    2014-06-01

    Full Text Available The paper deals with mathematical modelling and computer simulation of the seismic response of fuel assembly components. The seismic response is investigated by numerical integration method in time domain. The seismic excitation is given by two horizontal and one vertical synthetic accelerograms at the level of the pressure vessel seating. Dynamic response of the hexagonal type nuclear fuel assembly is caused by spatial motion of the support plates in the reactor core investigated on the reactor global model. The modal synthesis method with condensation is used for calculation of the fuel assembly component displacements and speeds on the level of the spacer grid cells.

  6. MAS NMR of HIV-1 protein assemblies

    Science.gov (United States)

    Suiter, Christopher L.; Quinn, Caitlin M.; Lu, Manman; Hou, Guangjin; Zhang, Huilan; Polenova, Tatyana

    2015-04-01

    The negative global impact of the AIDS pandemic is well known. In this perspective article, the utility of magic angle spinning (MAS) NMR spectroscopy to answer pressing questions related to the structure and dynamics of HIV-1 protein assemblies is examined. In recent years, MAS NMR has undergone major technological developments enabling studies of large viral assemblies. We discuss some of these evolving methods and technologies and provide a perspective on the current state of MAS NMR as applied to the investigations into structure and dynamics of HIV-1 assemblies of CA capsid protein and of Gag maturation intermediates.

  7. Fullerene assemblies toward photo-energy conversions.

    Science.gov (United States)

    Shen, Yanfei; Nakanishi, Takashi

    2014-04-28

    Manipulating molecular interaction and assembly for developing various functional nanostructures with controlled dimensionality, morphology and tailored properties is currently a research focus in molecular science and materials chemistry. Particularly, the self-organization of fullerenes (i.e. C60) to form various functional assemblies has received intense interest since it can provide excellent optoelectronic properties for photo-energy conversion-induced applications such as solar cells and field effect transistors (FET). In this perspective, we describe our recent efforts toward the development in the area of fullerene molecular design and assemblies aimed at improving the photoconductivity and photo-energy (electric and thermal) conversion systems.

  8. Lightweight IMM PV Flexible Blanket Assembly

    Science.gov (United States)

    Spence, Brian

    2015-01-01

    Deployable Space Systems (DSS) has developed an inverted metamorphic multijunction (IMM) photovoltaic (PV) integrated modular blanket assembly (IMBA) that can be rolled or z-folded. This IMM PV IMBA technology enables a revolutionary flexible PV blanket assembly that provides high specific power, exceptional stowed packaging efficiency, and high-voltage operation capability. DSS's technology also accommodates standard third-generation triple junction (ZTJ) PV device technologies to provide significantly improved performance over the current state of the art. This SBIR project demonstrated prototype, flight-like IMM PV IMBA panel assemblies specifically developed, designed, and optimized for NASA's high-voltage solar array missions.

  9. Classification of assembly techniques for micro products

    DEFF Research Database (Denmark)

    Hansen, Hans Nørgaard; Tosello, Guido; Gegeckaite, Asta

    2005-01-01

    Industrial production of micro products to be introduced in the market has to be reliable, fast, carried out at a reasonable price and in an acceptable quantity. One of the crucial steps in the process chain related to micro product manufacture is the assembly phase. Here components are handled...... of components and level of integration are made. This paper describes a systematic characterization of micro assembly methods. This methodology offers the opportunity of a cross comparison among different techniques to gain a choosing principle of the favourable micro assembly technology in a specific case...

  10. System and method for conveying an assembly

    KAUST Repository

    Eitelhuber, Georg

    2015-01-15

    An apparatus, system, and method for conveying an assembly along a track. A rail can include a first planar side, a second planar side, and a third planar side. The first, second, and third planar sides can be arranged to form at least two acute angles. A carriage assembly can include a drive wheel and at least two roller sets. The drive wheel can be configured to contact the first planar side and is configured to translate the carriage assembly along the rail. The at least two roller sets can be configured to contact the two other sides to maintain the carriage in contact with the rail.

  11. Computer organization and assembly language programming

    CERN Document Server

    Peterson, James L

    1978-01-01

    Computer Organization and Assembly Language Programming deals with lower level computer programming-machine or assembly language, and how these are used in the typical computer system. The book explains the operations of the computer at the machine language level. The text reviews basic computer operations, organization, and deals primarily with the MIX computer system. The book describes assembly language programming techniques, such as defining appropriate data structures, determining the information for input or output, and the flow of control within the program. The text explains basic I/O

  12. Virtual Teaching Simulation for Robot Assembly Accuracy Analysis

    Institute of Scientific and Technical Information of China (English)

    张征; 周宏甫; 刘斌

    2004-01-01

    In this paper, by teaching a 3D robot unit model and playing back to simulate the assembly process in a virtual assembly environment, errors in robot assembly are analyzed. The paper also presents a visualization method for analyzing accuracy of the robot assembly, and studies the influence of the spatial pose of a robot on the success rate of an axis-hole assembly, and accuracy of the robot teaching program in particular. Through integration of various errors and on the basis of assembly accuracy, tolerance of error sources can be reasonably distributed to meet the assembly accuracy requirement, therefore the planning of robot assembly unit can be improved.

  13. Biomolecular Assembly of Gold Nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Micheel, Christine Marya [Univ. of California, Berkeley, CA (United States)

    2005-05-20

    Over the past ten years, methods have been developed to construct discrete nanostructures using nanocrystals and biomolecules. While these frequently consist of gold nanocrystals and DNA, semiconductor nanocrystals as well as antibodies and enzymes have also been used. One example of discrete nanostructures is dimers of gold nanocrystals linked together with complementary DNA. This type of nanostructure is also known as a nanocrystal molecule. Discrete nanostructures of this kind have a number of potential applications, from highly parallel self-assembly of electronics components and rapid read-out of DNA computations to biological imaging and a variety of bioassays. My research focused in three main areas. The first area, the refinement of electrophoresis as a purification and characterization method, included application of agarose gel electrophoresis to the purification of discrete gold nanocrystal/DNA conjugates and nanocrystal molecules, as well as development of a more detailed understanding of the hydrodynamic behavior of these materials in gels. The second area, the development of methods for quantitative analysis of transmission electron microscope data, used computer programs written to find pair correlations as well as higher order correlations. With these programs, it is possible to reliably locate and measure nanocrystal molecules in TEM images. The final area of research explored the use of DNA ligase in the formation of nanocrystal molecules. Synthesis of dimers of gold particles linked with a single strand of DNA possible through the use of DNA ligase opens the possibility for amplification of nanostructures in a manner similar to polymerase chain reaction. These three areas are discussed in the context of the work in the Alivisatos group, as well as the field as a whole.

  14. Restauraciones estéticas de porcelana pura: Sistema Cercon Aesthetic all-ceramic restorations: Cercon System

    Directory of Open Access Journals (Sweden)

    E. Fernández Bodereau

    2011-10-01

    Full Text Available La estética en odontología está orientada a imitar la naturaleza, a tratar de conservar las proporciones, las formas, el color, la simetría. La tecnología ha desarrollado materiales cerámicos libres de metal que han reemplazado a los materiales tradicionales, capaces de imitar mejor a la naturaleza. El óxido de circonio parcialmente estabilizado con itrio, no solo es extremadamente resistente, sino que posee la ventaja de ser altamente translucido. Su translucidez de aproximadamente el 50% de la luz incidente, permite la elaboración de restauraciones con apariencia natural. La duración del proceso de escaneado y fresado dependerá del tamaño del objeto, del número de objetos procesados y de los pasos seleccionados (CAM o CAD/CAM. La estructura de óxido de circonio densamente sinterizado con su preciso ajuste, se cubre con la cerámica de recubrimiento que ha sido especialmente desarrollada para este propósito. En casi todos los casos que se nos plantean hay un solo diagnóstico, pero distintas alternativas de plantear el tratamiento. El éxito de estas restauraciones será predecible siempre que se fundamente en el conocimiento de los principios biológicos que la sustentan. El objetivo de esta publicación es exponer de manera concisa las bases teóricas a modo esquemático y las imágenes de la secuencia del tratamiento clínico.Aesthetic dentistry is dedicated to imitate nature by maintaining the size, shape, colour and symmetry. Technology has developed metal-free ceramic materials so capable of reproducing a natural appearance, that traditional materials have been replaced by them. The yttrium partially-stabilized zirconium oxide does not only have the advantage of being extremelly resistant, but it is also highly translucent. It has a translucency that allows about 50% of the incident light to pass through, a characteristic that is vital for providing a more natural appearance to restorations. The duration of scanning and milling procedures will depend on the size of the object, the number of objects proccessed and the steps selected (CAM or CAD/CAM. The framework of the densely sintered zirconium oxide with its precise fit is veneered with the veneering ceramic developed especially for this purpose. Almost in all cases, there are several treatment alternatives for the same diagnosis. The success of these restorations will be predicted as long as it is founded on sustaining biological principles. The aim of this paper is to concisely present the sequences for a clinical treatment in a schematic and illustrative manner.

  15. Anterior provisional restorations used to determine form, function, and esthetics for complex restorative situations, using all-ceramic restorative systems.

    Science.gov (United States)

    Reshad, Mamaly; Cascione, Domenico; Kim, Tae

    2010-02-01

    A technique is proposed for the restoration of a large and visible maxillary anterior defect. The importance of proper diagnosis, treatment planning, and communication is emphasized. Irreversible treatment should only be rendered once patient approval has been obtained through objective evaluation with provisional restorations. The techniques presented in this article use a combination of ceramic systems currently available to satisfy functional demands while achieving acceptable esthetics. A controlled series of steps, where the provisional restorative components are being replaced by the definitive ones is planned. The only difference between the provisional and definitive restorative components is the material used. The definitive restorations consisted of an implant-supported zirconium oxide framework. Individual pressed porcelain restorations were luted to the framework and a natural tooth. CLINICAL SIGNIFICANCE Provisional restorations allow an objective form of communication. Vertical and horizontal transitional lines can be effectively masked with appropriate treatment planning and a skilled ceramist. Many traditional dental laboratory steps may be eliminated or simplified without compromising the definitive restorations.

  16. Advance in clinical application of all ceramic materials%全瓷材料的临床应用进展

    Institute of Scientific and Technical Information of China (English)

    姚其卫; 牟月照

    2004-01-01

    全瓷材料化学性能稳定,生物性能优良,表面光泽度高,能恢复牙体组织的天然色彩,具有极佳的审美性.本文就全瓷材料在口腔修复中包括嵌体、贴面、全冠、固定桥、桩核及种植义齿修复等方面的临床应用,做了简要介绍,认为全瓷材料在口腔修复临床应用中具有极广阔的前景.

  17. Chairside Fabrication of an All-Ceramic Partial Crown Using a Zirconia-Reinforced Lithium Silicate Ceramic

    Directory of Open Access Journals (Sweden)

    Sven Rinke

    2016-01-01

    Full Text Available The chairside fabrication of a monolithic partial crown using a zirconia-reinforced lithium silicate (ZLS ceramic is described. The fully digitized model-free workflow in a dental practice is possible due to the use of a powder-free intraoral scanner and the computer-aided design/computer-assisted manufacturing (CAD/CAM of the restorations. The innovative ZLS material offers a singular combination of fracture strength (>370 Mpa, optimum polishing characteristics, and excellent optical properties. Therefore, this ceramic is an interesting alternative material for monolithic restorations produced in a digital workflow.

  18. Fracture strength of custom-fabricated Celay all-ceramic post and core restored endodontically treated teeth

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-xing; ZHANG Wei-hong; LU Zhi-yue; WANG Ke-li

    2006-01-01

    Background The increased use of ail-ceramic crown provides a rationale for tooth-colored core. Due to superior mechanicai properties, Vita Celay infiltration ceramic developed for crown and bridge works presents the potential for fabricating ail-ceramic posts and cores in one piece. This study was conducted to compare the fracture strength of endodontically treated teeth which were thereafter given different types of posts and cores and crowns restoration, respectively. The evaluated post-and-core systems are: custom-fabricated Celay ail-ceramic post-core, custom cast metal post-core, and prefabricated stainless steel post (Parapost) with and without 2.0 mm dentine ferrule.Methods Sixty freshly extracted human maxillary central incisors were endodonticaily treated and randomly divided into five groups with 12 samples each. Group A: Celay ceramic post-cores restored teeth with 2.0 mm dentine ferrule. Group B: Celay ceramic post-cores restored teeth with no dentine ferrule. Group C: cast metal post-cores restored teeth with 2.0 mm dentine ferrule. Group D: cast metal post-cores restored teeth with no dentine ferrule. Group E: prefabricated post and composite cores restored teeth with 2.0 mm dentine ferrule. All teeth were restored with Celay ceramic crowns. Each specimen was subjected to a load at a 45-degree angle to the long axis on MTS 810 material testing machine until failure, at crosshead speed of 0.02 em/minute. Analysis of variance followed by the Newman-Keuls pairwise multiple comparison tests were used to compare the results of the groups tested.Results There was a statistically significant difference among the five groups (P<0.01). Celay ceramic post-cores restored teeth with 2.0 mm dentine ferrule [(758.35±119.26) N] and cast metal post-cores restored teeth with 2.0 mm dentine ferrule [(756.63 ±166.22) N] had a significantly greater mean fracture strength than the other three groups in which no significant difference was observed. The 2.0 mm dentine ferrule could cause significant fracture resistance alteration of Celay post-core restored teeth.Conclusions When covered with Celay ceramic crowns, Celay post-cores restored teeth with 2.0 mm dentine ferrule and cast metal post-cores restored teeth with 2.0 mm dentine ferrule have similar fracture strength. There was a statistically significant difference between the fracture resistance of Celay post-core restored teeth with and without 2.0 mm dentine ferrule.

  19. Fracture resistance of a selection of full-contour all-ceramic crowns: an in vitro study.

    Science.gov (United States)

    Zesewitz, Tim F; Knauber, Andreas W; Northdurft, Frank P

    2014-01-01

    This study aimed to evaluate the fracture resistance of monolithic single crowns made from zirconia (ZI), lithium disilicate (LS2), or feldspar ceramic (FC). Five groups of crowns representing a maxillary first molar were made with the appropriate dimensions according to the manufacturer's instructions. The ZI and LS2 crowns were luted adhesively or cemented conventionally on a metal abutment tooth analog. The feldspar ceramic crowns were luted adhesively. All specimens underwent axial loading until fracture. The crowns in the ZI groups possessed the highest fracture resistance independent of the mode of fixation.

  20. Chairside Fabrication of an All-Ceramic Partial Crown Using a Zirconia-Reinforced Lithium Silicate Ceramic

    Science.gov (United States)

    Pabel, Anne-Kathrin; Rödiger, Matthias

    2016-01-01

    The chairside fabrication of a monolithic partial crown using a zirconia-reinforced lithium silicate (ZLS) ceramic is described. The fully digitized model-free workflow in a dental practice is possible due to the use of a powder-free intraoral scanner and the computer-aided design/computer-assisted manufacturing (CAD/CAM) of the restorations. The innovative ZLS material offers a singular combination of fracture strength (>370 Mpa), optimum polishing characteristics, and excellent optical properties. Therefore, this ceramic is an interesting alternative material for monolithic restorations produced in a digital workflow. PMID:27042362

  1. Preparation of All-Ceramic, High Performance Li-ion Batteries for Deep Space Power Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Lithium (Li) ion batteries are among the most promising power sources for many civilian, military and space applications due to their high power and high energy...

  2. Slipping past the spindle assembly checkpoint.

    Science.gov (United States)

    Subramanian, Radhika; Kapoor, Tarun M

    2013-11-01

    Error-free genome segregation depends on the spindle assembly checkpoint (SAC), a signalling network that delays anaphase onset until chromosomes have established proper spindle attachments. Three reports now quantitatively examine the sensitivity and robustness of the SAC response.

  3. Torsional fluctuations in columnar DNA assemblies

    CERN Document Server

    Lee, D J

    2005-01-01

    In columnar assemblies of helical bio-molecules the azimuthal degrees of freedom, i.e. rotations about the long axes of molecules, may be important in determining the structure of the assemblies especially when the interaction energy between neighbouring molecules explicitly depends on their relative azimuthal orientations. For DNA this leads to a rich variety of mesophases for columnar assemblies, each categorized by a specific azimuthal ordering. In a preceding paper [A. Wynveen, D. J. Lee, and A. A. Kornyshev, Eur. Phys. J. E, 16, 303 (2005)] a statistical mechanical theory was developed for the assemblies of torsionally rigid molecues in order to determine how thermal fluctuations influence the structure of these mesophases. Here we extend this theory by including torsional fluctuations of the molecules, where a DNA molecule may twist about its long axis at the cost of torsional elastic energy. Comparing this with the previous study, we find that inclusion of torsional fluctuations further increases the d...

  4. 2007 General Assembly: Work, decisions, appeal…

    CERN Multimedia

    Association du personnel

    2008-01-01

    The Staff Association General Assembly was held on 11 April in the main auditorium. According to tradition, a report of the activities of the past year was made and everyone was able to assess the extent of the work accomplished.

  5. Fathead minnow genome sequencing and assembly

    Data.gov (United States)

    U.S. Environmental Protection Agency — The dataset provides the URLs for accessing the genome sequence data and two draft assemblies as well as fathead minnow genotyping data associated with estimating...

  6. Molecular motor assembly of a biomimetic system

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction.

  7. V-GAP: Viral genome assembly pipeline

    KAUST Repository

    Nakamura, Yoji

    2015-10-22

    Next-generation sequencing technologies have allowed the rapid determination of the complete genomes of many organisms. Although shotgun sequences from large genome organisms are still difficult to reconstruct perfect contigs each of which represents a full chromosome, those from small genomes have been assembled successfully into a very small number of contigs. In this study, we show that shotgun reads from phage genomes can be reconstructed into a single contig by controlling the number of read sequences used in de novo assembly. We have developed a pipeline to assemble small viral genomes with good reliability using a resampling method from shotgun data. This pipeline, named V-GAP (Viral Genome Assembly Pipeline), will contribute to the rapid genome typing of viruses, which are highly divergent, and thus will meet the increasing need for viral genome comparisons in metagenomic studies.

  8. Optimal production planning for PCB assembly

    CERN Document Server

    Ho, William

    2006-01-01

    Focuses on the optimization of the Printed circuit board (PCB) assembly lines' efficiency. This book integrates the component sequencing and the feeder arrangement problems together for the pick-and-place machine and the chip shooter machines.

  9. SolidWorks 2011 Assemblies Bible

    CERN Document Server

    Lombard, Matt

    2011-01-01

    A fan of the SolidWorks Bible, but want more detail on assemblies? Here you go. SolidWorks fans have long sought more detail on SolidWorks topics, and now you have it. We took our popular SolidWorks Bible, divided it into two books (SolidWorks 2011 Assemblies Bible and SolidWorks 2011 Parts Bible) and packed each new book with a host of items from your wish lists, such as more extensive coverage of the basics, additional tutorials, and expanded coverage of topics largely ignored by other books. This SolidWorks 2011 Assemblies Bible shows you how to organize parts data to create assemblies or s

  10. BWR Assembly Optimization for Minor Actinide Recycling

    Energy Technology Data Exchange (ETDEWEB)

    G. Ivan Maldonado; John M. Christenson; J.P. Renier; T.F. Marcille; J. Casal

    2010-03-22

    The Primary objective of the proposed project is to apply and extend the latest advancements in LWR fuel management optimization to the design of advanced boiling water reactor (BWR) fuel assemblies specifically for the recycling of minor actinides (MAs).

  11. Biophysical Regulation of Vascular Differentiation and Assembly

    CERN Document Server

    Gerecht, Sharon

    2011-01-01

    The ability to grow stem cells in the laboratory and to guide their maturation to functional cells allows us to study the underlying mechanisms that govern vasculature differentiation and assembly in health and disease. Accumulating evidence suggests that early stages of vascular growth are exquisitely tuned by biophysical cues from the microenvironment, yet the scientific understanding of such cellular environments is still in its infancy. Comprehending these processes sufficiently to manipulate them would pave the way to controlling blood vessel growth in therapeutic applications. This book assembles the works and views of experts from various disciplines to provide a unique perspective on how different aspects of its microenvironment regulate the differentiation and assembly of the vasculature. In particular, it describes recent efforts to exploit modern engineering techniques to study and manipulate various biophysical cues. Biophysical Regulation of Vascular Differentiation and Assembly provides an inter...

  12. Magnetically mediated vortexlike assembly of gold nanoshells.

    Science.gov (United States)

    Sun, Jianfei; Dong, Jian; Sun, Dongke; Guo, Zhirui; Gu, Ning

    2012-04-24

    Gold nanoshells currently attract increasing research interests due to the important role in many subjects. For practical applications, random arrangement of the nanoparticles is often unfavored so that the assembly of gold nanoshells is becoming a central issue. We here proposed to utilize time-variant magnetic field to direct the assembly of gold nanoshells. It was discovered that the alternating magnetic field can mediate the vortex-like assembly of gold nanoshells. The mechanism was explored and thought to be relative with the electric field of induction which caused the thermal gradient on the substrate and the electric force. The vortexlike structure as well as the assembly mechanism will play an important role in research and application of gold nanomaterials.

  13. Photonic hybrid assembly through flexible waveguides

    Science.gov (United States)

    Wörhoff, K.; Prak, A.; Postma, F.; Leinse, A.; Wu, K.; Peters, T. J.; Tichem, M.; Amaning-Appiah, B.; Renukappa, V.; Vollrath, G.; Balcells-Ventura, J.; Uhlig, P.; Seyfried, M.; Rose, D.; Santos, R.; Leijtens, X. J. M.; Flintham, B.; Wale, M.; Robbins, D.

    2016-05-01

    Fully automated, high precision, cost-effective assembly technology for photonic packages remains one of the main challenges in photonic component manufacturing. Next to the cost aspect the most demanding assembly task for multiport photonic integrated circuits (PICs) is the high-precision (±0.1 μm) alignment and fixing required for optical I/O in InP PICs, even with waveguide spot size conversion. In a European research initiative - PHASTFlex - we develop and investigate an innovative, novel assembly concept, in which the waveguides in a matching TriPleX interposer PIC are released during fabrication to make them movable. After assembly of both chips by flip-chip bonding on a common carrier, TriPleX based actuators and clamping functions position and fix the flexible waveguides with the required accuracy.

  14. Automated analysis for lifecycle assembly processes

    Energy Technology Data Exchange (ETDEWEB)

    Calton, T.L.; Brown, R.G.; Peters, R.R.

    1998-05-01

    Many manufacturing companies today expend more effort on upgrade and disposal projects than on clean-slate design, and this trend is expected to become more prevalent in coming years. However, commercial CAD tools are better suited to initial product design than to the product`s full life cycle. Computer-aided analysis, optimization, and visualization of life cycle assembly processes based on the product CAD data can help ensure accuracy and reduce effort expended in planning these processes for existing products, as well as provide design-for-lifecycle analysis for new designs. To be effective, computer aided assembly planning systems must allow users to express the plan selection criteria that apply to their companies and products as well as to the life cycles of their products. Designing products for easy assembly and disassembly during its entire life cycle for purposes including service, field repair, upgrade, and disposal is a process that involves many disciplines. In addition, finding the best solution often involves considering the design as a whole and by considering its intended life cycle. Different goals and constraints (compared to initial assembly) require one to re-visit the significant fundamental assumptions and methods that underlie current assembly planning techniques. Previous work in this area has been limited to either academic studies of issues in assembly planning or applied studies of life cycle assembly processes, which give no attention to automatic planning. It is believed that merging these two areas will result in a much greater ability to design for; optimize, and analyze life cycle assembly processes.

  15. Thermal Analysis of a TREAT Fuel Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Papadias, Dionissios [Argonne National Lab. (ANL), Argonne, IL (United States); Wright, Arthur E. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2014-07-09

    The objective of this study was to explore options as to reduce peak cladding temperatures despite an increase in peak fuel temperatures. A 3D thermal-hydraulic model for a single TREAT fuel assembly was benchmarked to reproduce results obtained with previous thermal models developed for a TREAT HEU fuel assembly. In exercising this model, and variants thereof depending on the scope of analysis, various options were explored to reduce the peak cladding temperatures.

  16. Establishment of China Nuclear Fuel Assembly Database

    Institute of Scientific and Technical Information of China (English)

    CHENPeng; ZHANGYing-chao; LIUTing-jin; JINYong-li

    2003-01-01

    During researching, designing, manufacturing and post irradiation, a large amount of data on fuel assembly of China nuclear power plants has been accumulated. It is necessary to collect the data together,so that the researchers, designers, manufactures and managers could use the data conveniently. It was proposed to establish a China Nuclear Fuel Assembly Database through the Internet on workstations during the year of 2003 to 2006, so the data would be shared in China nuclear industry.

  17. Subchannel Analysis of Wire Wrapped SCWR Assembly

    Directory of Open Access Journals (Sweden)

    Jianqiang Shan

    2014-01-01

    Full Text Available Application of wire wrap spacers in SCWR can reduce pressure drop and obtain better mixing capability. As a consequence, the required coolant pumping power is decreased and the coolant temperature profile inside the fuel bundle is flattened which will obviously decrease the peak cladding temperature. The distributed resistance model for wire wrap was developed and implemented in ATHAS subchannel analysis code. The HPLWR wire wrapped assembly was analyzed. The results show that: (1 the assembly with wire wrap can obtain a more uniform coolant temperature profile than the grid spaced assembly, which will result in a lower peak cladding temperature; (2 the pressure drop in a wire wrapped assembly is less than that in a grid spaced assembly, which can reduce the operating power of pump effectively; (3 the wire wrap pitch has significant effect on the flow in the assembly. Smaller Hwire/Drod will result in stronger cross flow a more uniform coolant temperature profile, and also a higher pressure drop.

  18. Self-assembly micro optical filter

    Science.gov (United States)

    Zhang, Ping (Cerina); Le, Kevin; Malalur-Nagaraja-Rao, Smitha; Hsu, Lun-Chen; Chiao, J.-C.

    2006-01-01

    Optical communication and sensor industry face critical challenges in manufacturing for system integration. Due to the assembly complexity and integration platform variety, micro optical components require costly alignment and assembly procedures, in which many required manual efforts. Consequently, self-assembly device architectures have become a great interest and could provide major advantages over the conventional optical devices. In this paper, we discussed a self-assembly integration platform for micro optical components. To demonstrate the adaptability and flexibility of the proposed optical device architectures, we chose a commercially available MEMS fabrication foundry service - MUMPs (Multi-User MEMS Process). In this work, polysilicon layers of MUMPS are used as the 3-D structural material for construction of micro component framework and actuators. However, because the polysilicon has high absorption in the visible and near infrared wavelength ranges, it is not suitable for optical interaction. To demonstrate the required optical performance, hybrid integration of materials was proposed and implemented. Organic compound materials were applied on the silicon-based framework to form the required optical interfaces. Organic compounds provide good optical transparency, flexibility to form filters or lens and inexpensive manufacturing procedures. In this paper, we have demonstrated a micro optical filter integrated with self-assembly structures. We will discuss the self-assembly mechanism, optical filter designs, fabrication issues and results.

  19. Mitochondrial ribosome assembly in health and disease.

    Science.gov (United States)

    De Silva, Dasmanthie; Tu, Ya-Ting; Amunts, Alexey; Fontanesi, Flavia; Barrientos, Antoni

    2015-01-01

    The ribosome is a structurally and functionally conserved macromolecular machine universally responsible for catalyzing protein synthesis. Within eukaryotic cells, mitochondria contain their own ribosomes (mitoribosomes), which synthesize a handful of proteins, all essential for the biogenesis of the oxidative phosphorylation system. High-resolution cryo-EM structures of the yeast, porcine and human mitoribosomal subunits and of the entire human mitoribosome have uncovered a wealth of new information to illustrate their evolutionary divergence from their bacterial ancestors and their adaptation to synthesis of highly hydrophobic membrane proteins. With such structural data becoming available, one of the most important remaining questions is that of the mitoribosome assembly pathway and factors involved. The regulation of mitoribosome biogenesis is paramount to mitochondrial respiration, and thus to cell viability, growth and differentiation. Moreover, mutations affecting the rRNA and protein components produce severe human mitochondrial disorders. Despite its biological and biomedical significance, knowledge on mitoribosome biogenesis and its deviations from the much-studied bacterial ribosome assembly processes is scarce, especially the order of rRNA processing and assembly events and the regulatory factors required to achieve fully functional particles. This article focuses on summarizing the current available information on mitoribosome assembly pathway, factors that form the mitoribosome assembly machinery, and the effect of defective mitoribosome assembly on human health.

  20. Traceable assembly of microparts using optical tweezers

    Science.gov (United States)

    Kim, Jung-Dae; Hwang, Sun-Uk; Lee, Yong-Gu

    2012-10-01

    Assembly of components with a size in the order of tens of micrometers or less is difficult because the gravitational forces become smaller than weak forces such as capillary, electrostatic and van der Waals forces. As such, the picked-up components commonly adhere to the manipulator, making the release operation troublesome, and the repeatable supply of components cannot be guaranteed because the magazining and bunkering scheme available in conventional scale assembly cannot be extended to these small objects. Moreover, there are also no effective ways known to deliver the finalized assembly externally. In this paper, we present the manipulation and assembly of microparts using optical tweezers, which by nature do not have stiction problems. Techniques allowing bunkering and finalizing the assembly for exporting are also presented. Finally, we demonstrate an exemplary microassembly formed by assembling two microparts: a movable microring and a microrod fixed on a glass substrate. We believe this traceable microassembly to be an important step forward for micro- and nano-manufacturing.

  1. Spontaneous Assembly of Exopolymers from Phytoplankton

    Directory of Open Access Journals (Sweden)

    Yong-Xue Ding

    2009-01-01

    Full Text Available Phytoplankton exopolymeric substances (EPS contribute significantly to the dissolved organic car bon (DOC pool in the ocean, playing crucial roles in the surface ocean car bon cycle. Recent studies have demonstrated that ~10% of marine DOC can self-assemble as microgels through electro static Ca bonds providing hotspots of enriched microbial substrate. How ever, the question whether EPS can self-assemble and the formation mechanisms for EPS microgels have not been examined. Here were port that EPS from three representative phytoplankton species, Synechococcus, Emiliania huxleyi, and Skeletonema costatum can spontaneously self assemble in artificial sea water (ASW, forming microscopic gels of ~ 3 - 4 _ in diameter. Different from the marine DOC polymers assembly, these EPS samples can self-assemble in Ca2+-free ASW. Further experiments from fluorescence enhancement and chemical composition analysis confirmed the existence of fair amounts of hydrophobic domains in these EPS samples. These results suggest that hydrophobic interactions play a key role in the assembly of EPS from these three species of marine phytoplankton.

  2. NIF Target Assembly Metrology Methodology and Results

    Energy Technology Data Exchange (ETDEWEB)

    Alger, E. T. [General Atomics, San Diego, CA (United States); Kroll, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dzenitis, E. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Montesanti, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hughes, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Swisher, M. [IAP, Livermore, CA (United States); Taylor, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Segraves, K. [IAP, Livermore, CA (United States); Lord, D. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Reynolds, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Castro, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Edwards, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2011-01-01

    During our inertial confinement fusion (ICF) experiments at the National Ignition Facility (NIF) we require cryogenic targets at the 1-cm scale to be fabricated, assembled, and metrologized to micron-level tolerances. During assembly of these ICF targets, there are physical dimensmetrology is completed using optical coordinate measurement machines that provide repeatable measurements with micron precision, while also allowing in-process data collection for absolute accuracy in assembly. To date, 51 targets have been assembled and metrologized, and 34 targets have been successfully fielded on NIF relying on these metrology data. In the near future, ignition experiments on NIF will require tighter tolerances and more demanding target assembly and metrology capability. Metrology methods, calculations, and uncertainty estimates will be discussed. Target diagnostic port alignment, target position, and capsule location results will be reviewed for the 2009 Energetics Campaign. The information is presented via control charts showing the effect of process improvements that were made during target production. Certain parameters, including capsule position, met the 2009 campaign specifications but will have much tighter requirements in the future. Finally, in order to meet these new requirements assembly process changes and metrology capability upgrades will be necessary.

  3. Identifying wrong assemblies in de novo short read primary sequence assembly contigs

    Indian Academy of Sciences (India)

    VANDNA CHAWLA; RAJNISH KUMAR; RAVI SHANKAR

    2016-09-01

    With the advent of short-reads-based genome sequencing approaches, large number of organisms are being sequencedall over the world. Most of these assemblies are done using some de novo short read assemblers and other relatedapproaches. However, the contigs produced this way are prone to wrong assembly. So far, there is a conspicuousdearth of reliable tools to identify mis-assembled contigs. Mis-assemblies could result from incorrectly deleted orwrongly arranged genomic sequences. In the present work various factors related to sequence, sequencing andassembling have been assessed for their role in causing mis-assembly by using different genome sequencing data.Finally, some mis-assembly detecting tools have been evaluated for their ability to detect the wrongly assembledprimary contigs, suggesting a lot of scope for improvement in this area. The present work also proposes a simpleunsupervised learning-based novel approach to identify mis-assemblies in the contigs which was found performingreasonably well when compared to the already existing tools to report mis-assembled contigs. It was observed that theproposed methodology may work as a complementary system to the existing tools to enhance their accuracy.

  4. SparseAssembler2: Sparse k-mer Graph for Memory Efficient Genome Assembly

    CERN Document Server

    Ye, Chengxi; Ma, Zhanshan Sam; Yu, Douglas W; Pop, Mihai

    2011-01-01

    Motivation: To tackle the problem of huge memory usage associated with de Bruijn graph-based algorithms, upon which some of the most widely used de novo genome assemblers have been built, we released SparseAssembler1. SparseAssembler1 can save as much as 90% memory consumption in comparison with the state-of-art assemblers, but it requires rounds of denoising to accurately assemble genomes. In this paper, we introduce a new general model for genome assembly that uses only sparse k-mers. The new model replaces the idea of the de Bruijn graph from the beginning, and achieves similar memory efficiency and much better robustness compared with our previous SparseAssembler1. Results: Based on the sparse k-mers graph model, we develop SparseAssembler2. We demonstrate that the decomposition of reads of all overlapping k-mers, which is used in existing de Bruijn graph genome assemblers, is overly cautious. We introduce a sparse k-mer graph structure for saving sparse k-mers, which greatly reduces memory space requirem...

  5. The continuous assembly and transfer of nanoelements

    Science.gov (United States)

    Kumar, Arun

    Patterned nanoelements on flexible polymeric substrates at micro/nano scale at high rate, low cost, and commercially viable route offer an opportunity for manufacturing devices with micro/nano scale features. These micro/nano scale now made with various nanoelement can enhance the device functionality in sensing and switching due to their improved conductivity and better mechanical properties. In this research the fundamental understanding of high rate assembly and transfer of nanoelements has been developed. To achieve this objective, three sub topics were made. In the first step, the use of electrophoresis for the controlled assembly of CNT's on interdigitated templates has been shown. The time scale of assembly reported is shorter than the previously reported assembly time (60 seconds). The mass deposited was also predicted using the Hamaker's law. It is also shown that pre-patterned CNT's could be transferred from the rigid templates onto flexible polymeric substrates using a thermoforming process. The time scale of transfer is less than one minute (50 seconds) and was found to be dependent on polymer chemistry. It was found that CNT's preferentially transfer from Au electrode to non-polar polymeric substrates (polyurethane and polyethylene terephalathate glycol) in the thermoforming process. In the second step, a novel process (Pulsed Electrophoresis) has been shown for the first time to assist the assembly of conducting polyaniline on gold nanowire interdigitated templates. This technique offers dynamic control over heat build-up, which has been a main drawback in the DC electrophoresis and AC dielectrophoresis as well as the main cause of nanowire template damage. The use of this technique allowed higher voltages to be applied, resulting in shorter assembly times (e.g., 17.4 seconds, assembly resolution of 100 nm). The pre-patterned templates with PANi deposition were subsequently used to transfer the nanoscale assembled PANi from the rigid templates to

  6. 21 CFR 890.3500 - External assembled lower limb prosthesis.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false External assembled lower limb prosthesis. 890.3500... External assembled lower limb prosthesis. (a) Identification. An external assembled lower limb prosthesis... the lower extremity. Examples of external assembled lower limb prostheses are the following:...

  7. The construction of the CMS electromagnetic calorimeter: crystal assembly

    CERN Multimedia

    2005-01-01

    This photogallery describes the whole sequence of crystal assembly up to the so-called supermodules of 1700 PWO crystals each. Figures 1-6: submodule (10 crystals + their APDs) assembly with alveola structures. Figs. 7-11: module assembly. Each module is composed by 400 or 500 crystals. Figs. 13-17: supermodule assembly, thermal screen and monitoring, transport.

  8. Competition between self-assembly and surface adsorption

    Science.gov (United States)

    Dudowicz, Jacek; Douglas, Jack F.; Freed, Karl F.

    2009-02-01

    We investigate a minimal equilibrium polymerization model for the competition between self-assembly on a boundary and in solution that arises when an assembling system is in the presence of an adsorbing interface. Adsorption generally occurs upon cooling, but assembly (equilibrium polymerization) may arise either upon cooling or heating. Both cases are shown to exhibit a coupling between adsorption and self-assembly. When both assembly and adsorption proceed upon cooling, a change in the ratio of the enthalpy of adsorption to the enthalpy of assembly in solution can switch the system between a predominance of self-assembly in solution to assembly on the substrate. If assembly is promoted by heating and adsorption by cooling, as in many self-assembling proteins in aqueous solution, then a self-assembly analog of a closed loop phase boundary is found. In particular, the order parameter for assembly on the surface exhibits a peak as a function of temperature. As demonstrated by illustrative examples, the coupling between surface adsorption and self-assembly provides a powerful means of switching self-assembly processes on and off. Understanding and controlling this switching phenomenon will be useful in designing and directing self-assembly processes on surfaces for applications to nanomanufacturing and in developing treatments for diseases arising from pathological adsorption-induced assembly.

  9. Templated Self Assemble of Nano-Structures

    Energy Technology Data Exchange (ETDEWEB)

    Suo, Zhigang [Harvard University

    2013-04-29

    This project will identify and model mechanisms that template the self-assembly of nanostructures. We focus on a class of systems involving a two-phase monolayer of molecules adsorbed on a solid surface. At a suitably elevated temperature, the molecules diffuse on the surface to reduce the combined free energy of mixing, phase boundary, elastic field, and electrostatic field. With no template, the phases may form a pattern of stripes or disks. The feature size is on the order of 1-100 nm, selected to compromise the phase boundary energy and the long-range elastic or electrostatic interaction. Both experimental observations and our theoretical simulations have shown that the pattern resembles a periodic lattice, but has abundant imperfections. To form a perfect periodic pattern, or a designed aperiodic pattern, one must introduce a template to guide the assembly. For example, a coarse-scale pattern, lithographically defined on the substrate, will guide the assembly of the nanoscale pattern. As another example, if the molecules on the substrate surface carry strong electric dipoles, a charged object, placed in the space above the monolayer, will guide the assembly of the molecular dipoles. In particular, the charged object can be a mask with a designed nanoscale topographic pattern. A serial process (e.g., e-beam lithography) is necessary to make the mask, but the pattern transfer to the molecules on the substrate is a parallel process. The technique is potentially a high throughput, low cost process to pattern a monolayer. The monolayer pattern itself may serve as a template to fabricate a functional structure. This project will model fundamental aspects of these processes, including thermodynamics and kinetics of self-assembly, templated self-assembly, and self-assembly on unconventional substrates. It is envisioned that the theory will not only explain the available experimental observations, but also motivate new experiments.

  10. Lipid nanoparticle interactions and assemblies

    Science.gov (United States)

    Preiss, Matthew Ryan

    Novel liposome-nanoparticle assemblies (LNAs) provide a biologically inspired route for designing multifunctional bionanotheranostics. LNAs combine the benefits of lipids and liposomes to encapsulate, transport, and protect hydrophilic and hydrophobic therapeutics with functional nanoparticles. Functional nanoparticles endow LNAs with additional capabilities, including the ability to target diseases, triggered drug release, controlled therapeutic output, and diagnostic capabilities to produce a drug delivery system that can effectively and efficiently deliver therapeutics while reducing side effects. Not only could LNAs make existing drugs better, they could also provide an avenue to allow once promising non-approved drugs (rejected due to harmful side effects, inadequate pharmacokinetics, and poor efficacy) to be safely used through targeted and controlled delivery directly to the diseased site. LNAs have the potential to be stimuli responsive, delivering drugs on command by external (ultrasound, RF heating, etc.) or internal (pH, blood sugar, heart rate, etc.) stimuli. Individually, lipids and nanoparticles have been clinically approved for therapy, such as Doxil (a liposomal doxorubicin for cancer treatment), and diagnosis, such as Feridex (an iron oxide nanoparticle an MRI contrast enhancement agent for liver tumors). In order to engineer these multifunctional LNAs for theranostic applications, the interactions between nanoparticles and lipids must be better understood. This research sought to explore the formation, design, structures, characteristics, and functions of LNAs. To achieve this goal, different types of LNAs were formed, specifically magnetoliposomes, bilayer decorated LNAs (DLNAs), and lipid-coated magnetic nanoparticles (LMNPs). A fluorescent probe was embedded in the lipid bilayer of magnetoliposomes allowing the local temperature and membrane fluidity to be observed. When subjected to an electromagnetic field that heated the encapsulated iron

  11. RESEARCH ON THE CONSTRAINT MAPPING FROM FUNCTION TO ASSEMBLY

    Institute of Scientific and Technical Information of China (English)

    Tan Jianrong; Ji Yangjian; Liu Zhenyu; Chen Hongliang; Yue Xiaoli

    2003-01-01

    Assembly sketch is not only the visualization of abstract function, but also the template of detail design. Two kinds of information are needed to create assembly sketch: structure and assembly constraint. Most researches are aimed at how to obtain structures from function, but the problem of how to obtain assembly constraint from function is ignored. Following the definition of assembly unit and the classification of function, a hierarchical mapping method from function to assembly constraint is put forward, and the mapping method includes two steps. The first step is the mapping from function to assembly semantics which is assembly expression and accordant with engineer's design habit. The second one is the mapping from assembly semantics to basic assembly constraints that are convenient for computer to handle. The mapping method is applied to DDMS (design, drafting and management system) successfully.

  12. Method of making hermetic seals for hermetic terminal assemblies

    Science.gov (United States)

    Hsu, John S.; Marlino, Laura D.; Ayers, Curtis W.

    2010-04-13

    This invention teaches methods of making a hermetic terminal assembly comprising the steps of: inserting temporary stops, shims and jigs on the bottom face of a terminal assembly thereby blocking assembly core open passageways; mounting the terminal assembly inside a vacuum chamber using a temporary assembly perimeter seal and flange or threaded assembly interfaces; mixing a seal admixture and hardener in a mixer conveyor to form a polymer seal material; conveying the polymer seal material into a polymer reservoir; feeding the polymer seal material from the reservoir through a polymer outlet valve and at least one polymer outlet tube into the terminal assembly core thereby filling interstitial spaces in the core adjacent to service conduits, temporary stop, and the terminal assembly casing; drying the polymer seal material at room temperature thereby hermetically sealing the core of the terminal assembly; removing the terminal assembly from the vacuum chamber, and; removing the temporary stops, shims.

  13. Realization Techniques of Virtual Assembly Process Planning System

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-hua; NING Ru-xin; TANG Cheng-tong

    2005-01-01

    The key realization techniques of virtual assembly process planning (VAPP) system are analyzed,including virtual assembly model, real-time collision detection, automatic constraint recognition algorithm, cable harness assembly process planning and visual assembly process plan at the workshop. A virtual assembly model based on hierarchical assembly task list (HATL) is put forward, in which assembly tasks are defined to express component assembling operations and are sequentially and hierarchically organized according to different subassemblies, which can perfectly model the construction process of product. And a multi-layer automatic geometry constraint recognition algorithm of how to identify assembly constraint relations in the virtual environment is proposed, then a four-layer collision detection algorithm is discussed. A VAPP system is built and some simple mechanical assemblies are used to illustrate the feasibility of the proposed method and algorithms.

  14. A Magnetic Assembly, a Fluid-Flow Assembly and an Indicator

    DEFF Research Database (Denmark)

    2011-01-01

    The invention provides a magnetic assembly, the assembly comprising: a magnet (4); and a ferromagnetic component (6) having at least two regions of different Curie temperature, the magnet (4) and the ferromagnetic component being movable with respect to each other in dependence on the temperature...

  15. Nanoparticle Array Assembly Using Chemical Templates

    Science.gov (United States)

    Adams, Sarah Marie

    This dissertation demonstrates chemically-driven self-assembly techniques to produce assemblies of closely-spaced metal nanoparticles from colloidal nanoparticle solution in order to engineer enhanced optical fields. Planar nanoparticle assemblies provide a platform for a multitude of applications and material architectures. With nanoscale inter-particle spacing, metallic nanoparticles enable increased efficiency of photovoltaic devices due to light focusing and enhancement of electromagnetic fields useful for optical sensing of molecules due to coupling of the plasmon resonance in nanoparticle gaps. For molecular sensors, development of self-assembled two-dimensional assemblies of closely-spaced nanoparticles is useful for producing surface plasmon resonance sensors and surface-enhanced Raman spectroscopy (SERS) based sensing. Using chemical self-assembly, monodisperse, colloidal gold nanoparticles were attached on self-organized polymer templates in order to pattern assemblies of nanoparticle clusters with sub-10 nanometer inter-particle spacing. First citrate-stabilized Au nanoparticles were functionalized with thioctic acid ligands in solution. Then poly(methyl methacrylate) domains in phase-separated poly(styrene-block-methyl methacrylate) (PS-b-PMMA) thin films were chemically modified with surface amine functional groups. Au nanoparticles were preferentially attached to the functionalized PMMA surface domains using cross-linking chemistry. This method allows for versatility of size, shape, and composition. In this dissertation, we demonstrated attachment of 5, 10, and 20 nm Au and 20 nm Ag nanoparticles. PS-b-PMMA thin films also exhibit versatility of domain size and morphology by varying polymer molecular weights. The nanoparticle diameter to PMMA domain size ratio influenced the cluster size. As the ratio decreased, larger clusters were observed on PMMA domains with increased frequency. SERS measurement of nanoparticle assemblies showed uniform signal

  16. [INVITED] Self-assembled optical metamaterials

    Science.gov (United States)

    Baron, Alexandre; Aradian, Ashod; Ponsinet, Virginie; Barois, Philippe

    2016-08-01

    Self-assembled metamaterials constitute a promising platform to achieving bulk and homogenous optical materials that exhibit unusual effective medium properties. For many years now, the research community has contemplated lithographically fabricated metasurfaces, with extraordinary optical features. However, achieving large volumes at low cost is still a challenge by top-down fabrication. Bottom-up fabrication, that relies both on nanochemistry and self-assembly, is capable of building such materials while greatly reducing the energy footprint in the formulation of the metamaterial. Self-assembled metamaterials have shown that they are capable of reaching unprecedented values of bulkiness and homogeneity figures of merit. This feat is achieved by synthesizing plasmonic nanoresonators (meta-atoms in the sense of artificial polarizable units) and assembling them into a fully three-dimensional matrix through a variety of methods. Furthermore it has been shown that a wide range of material parameters can be tailored by controlling the geometry and composition of the meta-atoms as well as the volume fraction of the nano-objects in the metamaterial. Here we conduct a non-comprehensive review of some of the recent trends in self-assembled optical metamaterials and illustrate these trends with our recent work.

  17. Nanopropulsion by biocatalytic self-assembly.

    Science.gov (United States)

    Leckie, Joy; Hope, Alexander; Hughes, Meghan; Debnath, Sisir; Fleming, Scott; Wark, Alastair W; Ulijn, Rein V; Haw, Mark D

    2014-09-23

    A number of organisms and organelles are capable of self-propulsion at the micro- and nanoscales. Production of simple man-made mimics of biological transportation systems may prove relevant to achieving movement in artificial cells and nano/micronscale robotics that may be of biological and nanotechnological importance. We demonstrate the propulsion of particles based on catalytically controlled molecular self-assembly and fiber formation at the particle surface. Specifically, phosphatase enzymes (acting as the engine) are conjugated to a quantum dot (the vehicle), and are subsequently exposed to micellar aggregates (fuel) that upon biocatalytic dephosphorylation undergo fibrillar self-assembly, which in turn causes propulsion. The motion of individual enzyme/quantum dot conjugates is followed directly using fluorescence microscopy. While overall movement remains random, the enzyme-conjugates exhibit significantly faster transport in the presence of the fiber forming system, compared to controls without fuel, a non-self-assembling substrate, or a substrate which assembles into spherical, rather than fibrous structures upon enzymatic dephosphorylation. When increasing the concentration of the fiber-forming fuel, the speed of the conjugates increases compared to non-self-assembling substrate, although directionality remains random.

  18. Pulsed electric field assisted assembly of polyaniline

    Science.gov (United States)

    Kumar, Arun; Kazmer, David O.; Barry, Carol M. F.; Mead, Joey L.

    2012-08-01

    Assembling conducting polyaniline (PANi) on pre-patterned nano-structures by a high rate, commercially viable route offers an opportunity for manufacturing devices with nanoscale features. In this work we report for the first time the use of pulsed electric field to assist electrophoresis for the assembly of conducting polyaniline on gold nanowire interdigitated templates. This technique offers dynamic control over heat build-up, which has been a main drawback in the DC electrophoresis and AC dielectrophoresis as well as the main cause of nanowire template damage. The use of this technique allowed higher voltages to be applied, resulting in shorter assembly times (e.g., 17.4 s, assembly resolution of 100 nm). Moreover, the area coverage increases with the increase in number of pulses. A similar trend was observed with the deposition height and the increase in deposition height followed a linear trend with a correlation coefficient of 0.95. When the experimental mass deposited was compared with Hamaker’s theoretical model, the two were found to be very close. The pre-patterned templates with PANi deposition were subsequently used to transfer the nanoscale assembled PANi from the rigid templates to thermoplastic polyurethane using the thermoforming process.

  19. Preparation of the magnet sub-assemblies

    CERN Multimedia

    maximilien Brice

    2001-01-01

    Photo 01: On a rotation bench, preparation of the lower half-yoke with the bus bars and the pre-curved shell. The components are put on a dummy half-yoke in view of being rotated upside down. Photo 02: On a rotation bench, preparation of the lower half-yoke with the bus bars and the pre-curved shell. The components are put on a dummy half-yoke in view of being rotated upside down. Photo 03: The half-yoke assembly is made of short packs that are assembled together and locked with 15-m long tie-rods on a dedicated bench. Photo 04: The collared-coils assembly is equipped with magnetic inserts and special shims on a rotation bench in view of its installation in the yoke, operation that is called "yoking". At that stage of the assembly, the collared-coils assembly is equipped with the end plates and the electrical connections between the poles and between dipole I and dipoe II are made.

  20. Solar central receiver heliostat reflector assembly

    Science.gov (United States)

    Horton, Richard H.; Zdeb, John J.

    1980-01-01

    A heliostat reflector assembly for a solar central receiver system comprises a light-weight, readily assemblable frame which supports a sheet of stretchable reflective material and includes mechanism for selectively applying tension to and positioning the sheet to stretch it to optical flatness. The frame is mounted on and supported by a pipe pedestal assembly that, in turn, is installed in the ground. The frame is controllably driven in a predetermined way by a light-weight drive system so as to be angularly adjustable in both elevation and azimuth to track the sun and efficiently continuously reflect the sun's rays to a focal zone, i.e. central receiver, which forms part of a solar energy utilization system, such as a solar energy fueled electrical power generation system. The frame may include a built-in system for testing for optical flatness of the reflector. The preferable geometric configuration of the reflector is octagonal; however, it may be other shapes, such as hexagonal, pentagonal or square. Several different embodiments of means for tensioning and positioning the reflector to achieve optical flatness are disclosed. The reflector assembly is based on the stretch frame concept which provides an extremely light-weight, simple, low-cost reflector assembly that may be driven for positioning and tracking by a light-weight, inexpensive drive system.

  1. Programming biomolecular self-assembly pathways.

    Science.gov (United States)

    Yin, Peng; Choi, Harry M T; Calvert, Colby R; Pierce, Niles A

    2008-01-17

    In nature, self-assembling and disassembling complexes of proteins and nucleic acids bound to a variety of ligands perform intricate and diverse dynamic functions. In contrast, attempts to rationally encode structure and function into synthetic amino acid and nucleic acid sequences have largely focused on engineering molecules that self-assemble into prescribed target structures, rather than on engineering transient system dynamics. To design systems that perform dynamic functions without human intervention, it is necessary to encode within the biopolymer sequences the reaction pathways by which self-assembly occurs. Nucleic acids show promise as a design medium for engineering dynamic functions, including catalytic hybridization, triggered self-assembly and molecular computation. Here, we program diverse molecular self-assembly and disassembly pathways using a 'reaction graph' abstraction to specify complementarity relationships between modular domains in a versatile DNA hairpin motif. Molecular programs are executed for a variety of dynamic functions: catalytic formation of branched junctions, autocatalytic duplex formation by a cross-catalytic circuit, nucleated dendritic growth of a binary molecular 'tree', and autonomous locomotion of a bipedal walker.

  2. Assembling and Installing LRUs for NIF

    Energy Technology Data Exchange (ETDEWEB)

    Bonanno, R E

    2003-12-31

    Within the 192 National Ignition Facility (NIF) beamlines, there are over 7000 large (40 x 40 cm) optical components, including laser glass, mirrors, lenses, and polarizers. These optics are held in large opto-mechanical assemblies called line-replaceable units (LRUs). Each LRU has strict specifications with respect to cleanliness, alignment, and wavefront so that once activated, each NIF beamline will meet its performance requirements. NIF LRUs are assembled, tested, and refurbished in on-site cleanroom facilities. The assembled LRUs weigh up to 1800 kilograms, and are about the size of a phone booth. They are transported in portable clean canisters and inserted into the NIF beampath using robotic transporters. This plug and play design allows LRUs to be easily removed from the beampath for maintenance or upgrades. Commissioning of the first NIF quad, an activity known as NIF Early Light (NEL), has validated LRU designs and architecture, as well as demonstrated that LRUs can be assembled and installed as designed. Furthermore, it has served to develop key processes and tools forming the foundation for NIF s long-term LRU production and maintenance strategy. As we look forward to building out the rest of NIF, the challenge lies in scaling up the production rate while maintaining quality, implementing process improvements, and fully leveraging the learning and experience gained from NEL. This paper provides an overview of the facilities, equipment and processes used to assemble and install LRUs in NIF.

  3. Molecular self-assembly at solid surfaces.

    Science.gov (United States)

    Otero, Roberto; Gallego, José María; de Parga, Amadeo L Vázquez; Martín, Nazario; Miranda, Rodolfo

    2011-11-23

    Self-assembly, the process by which objects initially distributed at random arrange into well-defined patterns exclusively due to their local mutual interactions without external intervention, is generally accepted to be the most promising method for large-scale fabrication of functional nanostructures. In particular, the ordering of molecular building-blocks deposited at solid surfaces is relevant for the performance of many organic electronic and optoelectronic devices, such as organic field-effect transistors (OFETs), organic light-emitting diodes (OLEDs) or photovoltaic solar cells. However, the fundamental knowledge on the nature and strength of the intermolecular and molecule-substrate interactions that govern the ordering of molecular adsorbates is, in many cases, rather scarce. In most cases, the structure and morphology of the organic-metal interface is not known and it is just assumed to be the same as in the bulk, thereby implicitly neglecting the role of the surface on the assembly. However, this approximation is usually not correct, and the evidence gathered over the last decades points towards an active role of the surface in the assembly, leading to self-assembled structures that only in a few occasions can be understood by considering just intermolecular interactions in solid or gas phases. In this work we review several examples from our recent research demonstrating the apparently endless variety of ways in which the surface might affect the assembly of organic adsorbates.

  4. Self-assembly of smallest magnetic particles.

    Science.gov (United States)

    Mehdizadeh Taheri, Sara; Michaelis, Maria; Friedrich, Thomas; Förster, Beate; Drechsler, Markus; Römer, Florian M; Bösecke, Peter; Narayanan, Theyencheri; Weber, Birgit; Rehberg, Ingo; Rosenfeldt, Sabine; Förster, Stephan

    2015-11-24

    The assembly of tiny magnetic particles in external magnetic fields is important for many applications ranging from data storage to medical technologies. The development of ever smaller magnetic structures is restricted by a size limit, where the particles are just barely magnetic. For such particles we report the discovery of a kind of solution assembly hitherto unobserved, to our knowledge. The fact that the assembly occurs in solution is very relevant for applications, where magnetic nanoparticles are either solution-processed or are used in liquid biological environments. Induced by an external magnetic field, nanocubes spontaneously assemble into 1D chains, 2D monolayer sheets, and large 3D cuboids with almost perfect internal ordering. The self-assembly of the nanocubes can be elucidated considering the dipole-dipole interaction of small superparamagnetic particles. Complex 3D geometrical arrangements of the nanodipoles are obtained under the assumption that the orientation of magnetization is freely adjustable within the superlattice and tends to minimize the binding energy. On that basis the magnetic moment of the cuboids can be explained.

  5. RESEARCH OF MOVEMENT NAVIGATION BASED ON ASSEMBLY CONSTRAINT RECOGNITION

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The requirements and features of virtual assembly movement navigator are analyzed to help operators flexibly manipulate virtual objects, precisely locate or assemble virtual parts in virtual environment. With the degree-of-freedom analysis, the assembly constraint hierarchical model is constructed and the system's constraints are built dynamically. Thus, all objects in virtual environment can be located reasonally by the navigator. Moreover, the assembly constraint recognition in the process of assembly and movement correction is also discussed.

  6. Whole-Genome Sequence Assembly for Mammalian Genomes: Arachne 2

    OpenAIRE

    Jaffe, David B.; Butler, Jonathan; Gnerre, Sante; Mauceli, Evan; Lindblad-Toh, Kerstin; Jill P. Mesirov; Michael C Zody; Lander, Eric S.

    2003-01-01

    We previously described the whole-genome assembly program Arachne, presenting assemblies of simulated data for small to mid-sized genomes. Here we describe algorithmic adaptations to the program, allowing for assembly of mammalian-size genomes, and also improving the assembly of smaller genomes. Three principal changes were simultaneously made and applied to the assembly of the mouse genome, during a six-month period of development: (1) Supercontigs (scaffolds) were iteratively broken and rej...

  7. Advanced membrane electrode assemblies for fuel cells

    Science.gov (United States)

    Kim, Yu Seung; Pivovar, Bryan S

    2014-02-25

    A method of preparing advanced membrane electrode assemblies (MEA) for use in fuel cells. A base polymer is selected for a base membrane. An electrode composition is selected to optimize properties exhibited by the membrane electrode assembly based on the selection of the base polymer. A property-tuning coating layer composition is selected based on compatibility with the base polymer and the electrode composition. A solvent is selected based on the interaction of the solvent with the base polymer and the property-tuning coating layer composition. The MEA is assembled by preparing the base membrane and then applying the property-tuning coating layer to form a composite membrane. Finally, a catalyst is applied to the composite membrane.

  8. Microcomponent assembly for efficient contacting of fluid

    Science.gov (United States)

    Drost, Monte K.; Wegeng, Robert S.; Friedrich, Michele; Hanna, William T.; Call, Charles J.; Kurath, Dean E.

    2000-01-01

    The present invention is a fundamental method and apparatus of a microcomponent assembly that overcomes the inherent limitations of state of the art chemical separations. The fundamental element enabling miniaturization is the porous contactor contained within a microcomponent assembly for mass transfer of a working compound from a first medium to a second medium. The porous contactor has a thickness, and a plurality of pores extending through the thickness. The pores are of a geometry cooperating with a boundary tension of one or the other or both of the media thereby preventing migration of one, other or both through the microporous contactor while permitting passage of the working compound. In the microcomponent assembly, the porous contactor is placed between a first laminate such that a first space or first microplenum is formed between the microporous contactor and the first laminate. Additionally, a cover sheet provides a second space or second plenum between the porous contactor and the cover sheet.

  9. [Ergonomic evaluation of assembly line of tractors].

    Science.gov (United States)

    Dellera, L; Buratti, G

    2012-01-01

    In the assembly lines in the engineering sector, ever more guided by the theories of lean production, is increasingly important ergonomic factor working conditions to preserve the health of workers and ensuring the performance. This analysis has focused on the study of biomechanical and postural stress of work tasks of an assembly line of the tractor, characterized by different weights and volumes from that of the car. Comparison with the technical standard of EN 1005-4 has allowed the identification as the machining assembly of small components result in conditions of acceptability, while most of the other processes aren't reliable. The emergence of these problems pushed to find several ergonomic solutions including the development of a special reclining seat to enable a proper posture during the working.

  10. Thermal Aspects Related to Power Assemblies

    Directory of Open Access Journals (Sweden)

    PLESCA, A.

    2010-02-01

    Full Text Available In many cases when a power assembly based on power semiconductors is used, catastrophic failure is the result of steep temperature gradient in the localized temperature distribution. Hence, an optimal heatsink design for certain industrial applications has become a real necessity. In this paper, the Pro/ENGINEER software with the thermal simulation integrated tool, Pro/MECHANICA, has been used for thermal study of a specific power semiconductor assembly. A series of steady-state and transient thermal simulations have been performed. The experimental tests have confirmed the simulation results. Therefore, the use of specific 3D modeling and simulation software allows to design special power semiconductor assemblies with a better thermal transfer between its heatsink and power electronic components at given operating conditions.

  11. Finishing of the cold mass assembly

    CERN Multimedia

    Maximilien Brice

    2001-01-01

    Photo 1 The connection-side end of the active part assembly. This view shows the electrical connections between the poles and the curved bus ended with flanges for the connection with the protection diode. Photo 2 The connection-side end of the active part assembly. This view shows the electrical connections between the poles, the auxiliary bus bars and the instrumentation wires. Photo 3 Lyre-side end of the active part assembly. One can see the mechanical support of the corretor magnets that are to be installed around the cold bore tubes. Photo 4 General view of the finishing station showing the special supporting structures (blue and yellow structures) needed for the geometric measurements and for the alignment operations. Around the magnet, there are datum points (on the tripodes) needed to build up the coordinates system for the measurements.

  12. Finishing of the cold mass assembly

    CERN Multimedia

    Maximilien Brice

    2001-01-01

    Photo 1 Zoom of the lyre-side end of the active part assembly. The extremity of the shrinking cylinder has been bevelled in view of welding the end cover. Photo 2 General view of the finishing station showing the special supporting structures (blue and yellow structures) needed for the geometric measurements and for the alignment operations. Photo 3 Zoom of the lyre-side end of the active part assembly. One can also see the auxiliary bus bars needed to power the corrector magnets that are installed in the dipole cold mass assembly. Photo 4 Technicians are putting in order the instrumentation wires. The prototype magnets were equipped with numerous sensors to monitor key parameters during the performance tests at cold conditions.

  13. Patterned self-assembled film guided electrodeposition

    Institute of Scientific and Technical Information of China (English)

    ZHOU; Feng; LI; Bin; XU; Tao; CHEN; Miao; HAO; Jingcheng; LI

    2004-01-01

    The paper describes the fabrication of polypyrrole (PPy) microstructures through patterned self-assembled film guided electrodeposition. Thus the patterned self-assembled monolayer is prepared by microcontact printing (μCP) and used as the template in the electrodeposition of PPy. It has been found that the self-assembled monolayer plays completely different roles on different substrates in directing the deposition of the PPy. Namely, the electrodeposition mainly occurs on the exposed area of the gold substrates patterned with dodecanethiol (DDT) and octadecanelthiol (ODT) and on the indium tin oxide (ITO) substrate patterned with octadecyltrichlorosilane (OTS), while PPy nucleates on the OTS covered area and no deposition is found on the exposed area of a semiconductor substrate (silicon). This is attributed to the cooperative effect between the substrate conductivity and the compatibility of the PPy oligomer with the covered or exposed area of the substrate surface.

  14. S-layer protein self-assembly.

    Science.gov (United States)

    Pum, Dietmar; Toca-Herrera, Jose Luis; Sleytr, Uwe B

    2013-01-25

    Crystalline S(urface)-layers are the most commonly observed cell surface structures in prokaryotic organisms (bacteria and archaea). S-layers are highly porous protein meshworks with unit cell sizes in the range of 3 to 30 nm, and thicknesses of ~10 nm. One of the key features of S-layer proteins is their intrinsic capability to form self-assembled mono- or double layers in solution, and at interfaces. Basic research on S-layer proteins laid foundation to make use of the unique self-assembly properties of native and, in particular, genetically functionalized S-layer protein lattices, in a broad range of applications in the life and non-life sciences. This contribution briefly summarizes the knowledge about structure, genetics, chemistry, morphogenesis, and function of S-layer proteins and pays particular attention to the self-assembly in solution, and at differently functionalized solid supports.

  15. New inlet nozzle assembly: C Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Calkin, J.F.

    1960-10-19

    The use of self-supported fuel elements in ribless Zircaloy-2 tubes at C-Reactor requires some inlet nozzle modification to allow charging of the larger overall diameter fuel pieces. A new nozzle assembly has been developed (by Equipment Development Operation -- IPD) which will allow use of the new fuel pieces and at the same time increase the reliability of the header-to-tube piping and reduce pumping power losses. Flow test data were requested for the new assembly and the results of these tests are presented herein. This report also presents a comparison of the header to tube energy losses for the various reactor inlet nozzle assemblies which are currently used on the Hanford production reactors.

  16. Hierarchical silica particles by dynamic multicomponent assembly

    DEFF Research Database (Denmark)

    Wu, Z. W.; Hu, Q. Y.; Pang, J. B.;

    2005-01-01

    Abstract: Aerosol-assisted assembly of mesoporous silica particles with hierarchically controllable pore structure has been prepared using cetyltrimethylammonium bromide (CTAB) and poly(propylene oxide) (PPO, H[OCH(CH3)CH2],OH) as co-templates. Addition of the hydrophobic PPO significantly...... influences the delicate hydrophilic-hydrophobic balance in the well-studied CTAB-silicate co-assembling system, resulting in various mesostructures (such as hexagonal, lamellar, and hierarchical structure). The co-assembly of CTAB, silicate clusters, and a low-molecular-weight PPO (average M-n 425) results...... in a uniform lamellar structure, while the use of a high-molecular-weight PPO (average M-n 2000), which is more hydrophobic, leads to the formation of hierarchical pore structure that contains meso-meso or meso-macro pore structure. The role of PPO additives on the mesostructure evolution in the CTAB...

  17. Advances in Multiferroic Nanomaterials Assembled with Clusters

    Directory of Open Access Journals (Sweden)

    Shifeng Zhao

    2015-01-01

    Full Text Available As an entirely new perspective of multifunctional materials, multiferroics have attracted a great deal of attention. With the rapidly developing micro- and nano-electro-mechanical system (MEMS&NEMS, the new kinds of micro- and nanodevices and functionalities aroused extensive research activity in the area of multiferroics. As an ideal building block to assemble the nanostructure, cluster exhibits particular physical properties related to the cluster size at nanoscale, which is efficient in controlling the multiferroic properties for nanomaterials. This review focuses on our recent advances in multiferroic nanomaterials assembled with clusters. In particular, the single phase multiferroic films and compound heterostructured multiferroic films assembled with clusters were introduced detailedly. This technique presents a new and efficient method to produce the nanostructured multiferroic materials for their potential application in NEMS devices.

  18. Self-assembled gelators for organic electronics.

    Science.gov (United States)

    Babu, Sukumaran Santhosh; Prasanthkumar, Seelam; Ajayaghosh, Ayyappanpillai

    2012-02-20

    Nature excels at engineering materials by using the principles of chemical synthesis and molecular self-assembly with the help of noncovalent forces. Learning from these phenomena, scientists have been able to create a variety of self-assembled artificial materials of different size, shapes, and properties for wide ranging applications. An area of great interest in this regard is solvent-assisted gel formation with functional organic molecules, thus leading to one-dimensional fibers. Such fibers have improved electronic properties and are potential soft materials for organic electronic devices, particularly in bulk heterojunction solar cells. Described herein is how molecular self-assembly, which was originally proposed as a simple laboratory curiosity, has helped the evolution of a variety of soft functional materials useful for advanced electronic devices such as organic field-effect transistors and organic solar cells. Highlights on some of the recent developments are discussed.

  19. Template Assembly for Detailed Urban Reconstruction

    KAUST Repository

    Nan, Liangliang

    2015-05-04

    We propose a new framework to reconstruct building details by automatically assembling 3D templates on coarse textured building models. In a preprocessing step, we generate an initial coarse model to approximate a point cloud computed using Structure from Motion and Multi View Stereo, and we model a set of 3D templates of facade details. Next, we optimize the initial coarse model to enforce consistency between geometry and appearance (texture images). Then, building details are reconstructed by assembling templates on the textured faces of the coarse model. The 3D templates are automatically chosen and located by our optimization-based template assembly algorithm that balances image matching and structural regularity. In the results, we demonstrate how our framework can enrich the details of coarse models using various data sets.

  20. Pulse detonation assembly and hybrid engine

    Science.gov (United States)

    Rasheed, Adam (Inventor); Dean, Anthony John (Inventor); Vandervort, Christian Lee (Inventor)

    2010-01-01

    A pulse detonation (PD) assembly includes a number of PD chambers adapted to expel respective detonation product streams and a number of barriers disposed between respective pairs of PD chambers. The barriers define, at least in part, a number of sectors that contain at least one PD chamber. A hybrid engine includes a number of PD chambers and barriers. The hybrid engine further includes a turbine assembly having at least one turbine stage, being in flow communication with the PD chambers and being configured to be at least partially driven by the detonation product streams. A segmented hybrid engine includes a number of PD chambers and segments configured to receive and direct the detonation product streams from respective PD chambers. The segmented hybrid engine further includes a turbine assembly configured to be at least partially driven by the detonation product streams.

  1. Advanced DNA assembly technologies in drug discovery.

    Science.gov (United States)

    Tsvetanova, Billyana; Peng, Lansha; Liang, Xiquan; Li, Ke; Hammond, Linda; Peterson, Todd C; Katzen, Federico

    2012-05-01

    Recombinant DNA technologies have had a fundamental impact on drug discovery. The continuous emergence of unique gene assembly techniques resulted in the generation of a variety of therapeutic reagents such as vaccines, cancer treatment molecules and regenerative medicine precursors. With the advent of synthetic biology there is a growing need for precise and concerted assembly of multiple DNA fragments of various sizes, including chromosomes. In this article, we summarize the highlights of the recombinant DNA technology since its inception in the early 1970s, emphasizing on the most recent advances, and underscoring their principles, advantages and shortcomings. Current and prior cloning trends are discussed in the context of sequence requirements and scars left behind. Our opinion is that despite the remarkable progress that has enabled the generation and manipulation of very large DNA sequences, a better understanding of the cell's natural circuits is needed in order to fully exploit the current state-of-the-art gene assembly technologies.

  2. Comparing de novo assemblers for 454 transcriptome data

    Directory of Open Access Journals (Sweden)

    Blaxter Mark L

    2010-10-01

    Full Text Available Abstract Background Roche 454 pyrosequencing has become a method of choice for generating transcriptome data from non-model organisms. Once the tens to hundreds of thousands of short (250-450 base reads have been produced, it is important to correctly assemble these to estimate the sequence of all the transcripts. Most transcriptome assembly projects use only one program for assembling 454 pyrosequencing reads, but there is no evidence that the programs used to date are optimal. We have carried out a systematic comparison of five assemblers (CAP3, MIRA, Newbler, SeqMan and CLC to establish best practices for transcriptome assemblies, using a new dataset from the parasitic nematode Litomosoides sigmodontis. Results Although no single assembler performed best on all our criteria, Newbler 2.5 gave longer contigs, better alignments to some reference sequences, and was fast and easy to use. SeqMan assemblies performed best on the criterion of recapitulating known transcripts, and had more novel sequence than the other assemblers, but generated an excess of small, redundant contigs. The remaining assemblers all performed almost as well, with the exception of Newbler 2.3 (the version currently used by most assembly projects, which generated assemblies that had significantly lower total length. As different assemblers use different underlying algorithms to generate contigs, we also explored merging of assemblies and found that the merged datasets not only aligned better to reference sequences than individual assemblies, but were also more consistent in the number and size of contigs. Conclusions Transcriptome assemblies are smaller than genome assemblies and thus should be more computationally tractable, but are often harder because individual contigs can have highly variable read coverage. Comparing single assemblers, Newbler 2.5 performed best on our trial data set, but other assemblers were closely comparable. Combining differently optimal assemblies

  3. Quality Experiences in Aerospace Electronic Assembly

    Directory of Open Access Journals (Sweden)

    P.B.V. Rama Murthy

    2006-01-01

    Full Text Available Quality of the electronic assembly depends largely on good quality practices (GQP adoptedduring the process of electronic assembly. Quality experiences gained during working atthe defence and space laboratories have been used to develop good quality practices such asthree- tray method for cleaning of PCBs, use of grommets for cable routing, use of eye-piecelessstereo zoom microscope for visual testinglinspection, pre-tinning of components, desiccatorsfor storage, potting prior to conformal coating, continuity and isolation checks, de-golding ofleads prior to soldering, and use of flux-cored solder wire. The paper also discusses how andwhy these good quality practices were evolved.

  4. Rationally engineering natural protein assemblies in nanobiotechnology.

    Science.gov (United States)

    Howorka, Stefan

    2011-08-01

    Multimeric protein assemblies are essential components in viruses, bacteria, eukaryotic cells, and organisms where they act as cytoskeletal scaffold, storage containers, or for directional transport. The bottom-up structures can be exploited in nanobiotechnology by harnessing their built-in properties and combining them with new functional modules. This review summarizes the design principles of natural protein assemblies, highlights recent progress in their structural elucidation, and shows how rational engineering can create new biomaterials for applications in vaccine development, biocatalysis, materials science, and synthetic biology.

  5. Assembly planning at the micro scale

    Energy Technology Data Exchange (ETDEWEB)

    Feddema, J.T.; Xavier, P.; Brown, R.

    1998-05-14

    This paper investigates a new aspect of fine motion planning for the micro domain. As parts approach 1--10 {micro}m or less in outside dimensions, interactive forces such as van der Waals and electrostatic forces become major factors which greatly change the assembly sequence and path plans. It has been experimentally shown that assembly plans in the micro domain are not reversible, motions required to pick up a part are not the reverse of motions required to release a part. This paper develops the mathematics required to determine the goal regions for pick up, holding, and release of a micro-sphere being handled by a rectangular tool.

  6. Automatic Tool for Local Assembly Structures

    Energy Technology Data Exchange (ETDEWEB)

    2016-10-11

    Whole community shotgun sequencing of total DNA (i.e. metagenomics) and total RNA (i.e. metatranscriptomics) has provided a wealth of information in the microbial community structure, predicted functions, metabolic networks, and is even able to reconstruct complete genomes directly. Here we present ATLAS (Automatic Tool for Local Assembly Structures) a comprehensive pipeline for assembly, annotation, genomic binning of metagenomic and metatranscriptomic data with an integrated framework for Multi-Omics. This will provide an open source tool for the Multi-Omic community at large.

  7. Quality Assessment of Domesticated Animal Genome Assemblies

    DEFF Research Database (Denmark)

    Seemann, Stefan E; Anthon, Christian; Palasca, Oana;

    2015-01-01

    domesticated animal genomes still need to be sequenced deeper in order to produce high-quality assemblies. In the meanwhile, ironically, the extent to which RNAseq and other next-generation data is produced frequently far exceeds that of the genomic sequence. Furthermore, basic comparative analysis is often...... affected by the lack of genomic sequence. Herein, we quantify the quality of the genome assemblies of 20 domesticated animals and related species by assessing a range of measurable parameters, and we show that there is a positive correlation between the fraction of mappable reads from RNAseq data...

  8. Remote control of self-assembled microswimmers

    CERN Document Server

    Grosjean, Galien; Darras, Alexis; Hubert, Maxime; Lumay, Geoffroy; Vandewalle, Nicolas

    2015-01-01

    Physics governing the locomotion of microorganisms and other microsystems is dominated by viscous damping. An effective swimming strategy involves the non-reciprocal and periodic deformations of the considered body. Here, we show that a magnetocapillary-driven self-assembly, composed of three soft ferromagnetic beads, is able to swim along a liquid-air interface when powered by an external magnetic field. More importantly, we demonstrate that trajectories can be fully controlled, opening ways to explore low Reynolds number swimming. This magnetocapillary system spontaneously forms by self-assembly, allowing miniaturization and other possible applications such as cargo transport or solvent flows.

  9. Unified Framework for Finite Element Assembly

    CERN Document Server

    Alnæs, Martin Sandve; Mardal, Kent-Andre; Skavhaug, Ola; Langtangen, Hans Petter; 10.1504/IJCSE.2009.029160

    2012-01-01

    At the heart of any finite element simulation is the assembly of matrices and vectors from discrete variational forms. We propose a general interface between problem-specific and general-purpose components of finite element programs. This interface is called Unified Form-assembly Code (UFC). A wide range of finite element problems is covered, including mixed finite elements and discontinuous Galerkin methods. We discuss how the UFC interface enables implementations of variational form evaluation to be independent of mesh and linear algebra components. UFC does not depend on any external libraries, and is released into the public domain.

  10. Molecular assembly on two-dimensional materials

    Science.gov (United States)

    Kumar, Avijit; Banerjee, Kaustuv; Liljeroth, Peter

    2017-02-01

    Molecular self-assembly is a well-known technique to create highly functional nanostructures on surfaces. Self-assembly on two-dimensional (2D) materials is a developing field driven by the interest in functionalization of 2D materials in order to tune their electronic properties. This has resulted in the discovery of several rich and interesting phenomena. Here, we review this progress with an emphasis on the electronic properties of the adsorbates and the substrate in well-defined systems, as unveiled by scanning tunneling microscopy. The review covers three aspects of the self-assembly. The first one focuses on non-covalent self-assembly dealing with site-selectivity due to inherent moiré pattern present on 2D materials grown on substrates. We also see that modification of intermolecular interactions and molecule–substrate interactions influences the assembly drastically and that 2D materials can also be used as a platform to carry out covalent and metal-coordinated assembly. The second part deals with the electronic properties of molecules adsorbed on 2D materials. By virtue of being inert and possessing low density of states near the Fermi level, 2D materials decouple molecules electronically from the underlying metal substrate and allow high-resolution spectroscopy and imaging of molecular orbitals. The moiré pattern on the 2D materials causes site-selective gating and charging of molecules in some cases. The last section covers the effects of self-assembled, acceptor and donor type, organic molecules on the electronic properties of graphene as revealed by spectroscopy and electrical transport measurements. Non-covalent functionalization of 2D materials has already been applied for their application as catalysts and sensors. With the current surge of activity on building van der Waals heterostructures from atomically thin crystals, molecular self-assembly has the potential to add an extra level of flexibility and functionality for applications ranging

  11. Self-assembling segmented coiled tubing

    Energy Technology Data Exchange (ETDEWEB)

    Raymond, David W.

    2016-09-27

    Self-assembling segmented coiled tubing is a concept that allows the strength of thick-wall rigid pipe, and the flexibility of thin-wall tubing, to be realized in a single design. The primary use is for a drillstring tubular, but it has potential for other applications requiring transmission of mechanical loads (forces and torques) through an initially coiled tubular. The concept uses a spring-loaded spherical `ball-and-socket` type joint to interconnect two or more short, rigid segments of pipe. Use of an optional snap ring allows the joint to be permanently made, in a `self-assembling` manner.

  12. Self-assembly of small peptidomimetic cyclophanes.

    Science.gov (United States)

    Becerril, Jorge; Burguete, M Isabel; Escuder, Beatriu; Galindo, Francisco; Gavara, Raquel; Miravet, Juan F; Luis, Santiago V; Peris, Gabriel

    2004-08-20

    The self-assembly of a series of small peptidomimetic cyclophanes in organic solvents was studied. X-ray diffraction, NMR spectroscopy, and molecular modelling were used to understand the structural features of these self-assembling compounds both at the molecular and supramolecular level. The factors that could influence the formation of gels rather than crystals were studied and a model for the arrangement of molecules in the gel was proposed. Furthermore, scanning electron microscopy revealed that in some cases these compounds undergo a transcription of chirality when going from organogelator to helicoidal gel fibres.

  13. Single-particle study of protein assembly

    Science.gov (United States)

    Kiang, Ching-Hwa

    2001-10-01

    A study of protein assembly in solution with single-particle imaging and reconstruction techniques using cryoelectron microscopy is reported. The human glutamine synthetase enzyme, important in brain metabolism, and previously assumed to be assembled into a homogeneous quaternary structure, is found to be heterogeneous, with three oligomeric states that co-exist at room temperature. This result corrects an old structural and kinetic model determined by ensemble averaging techniques that assumed a homogeneous system. Unexpectedly fast protein dissociation kinetics results from a stabilized transition state.

  14. Modeling of Parameters of Subcritical Assembly SAD

    CERN Document Server

    Petrochenkov, S; Puzynin, I

    2005-01-01

    The accepted conceptual design of the experimental Subcritical Assembly in Dubna (SAD) is based on the MOX core with a nominal unit capacity of 25 kW (thermal). This corresponds to the multiplication coefficient $k_{\\rm eff} =0.95$ and accelerator beam power 1 kW. A subcritical assembly driven with the existing 660 MeV proton accelerator at the Joint Institute for Nuclear Research has been modelled in order to make choice of the optimal parameters for the future experiments. The Monte Carlo method was used to simulate neutron spectra, energy deposition and doses calculations. Some of the calculation results are presented in the paper.

  15. HTS 20 M 600 a link assembled

    CERN Document Server

    Ballarino, A

    2013-01-01

    The final deliverable of the EuCARD Task 7.5 activity is a 20 m long Superconducting Link made of HTS (High Temperature Superconducting) cables of the type and in quantity as required for the powering of the LHC superconducting circuits fed from LHC P7 (50 cables rated at 600 A). Following an intense R&D activity, which included the study of novel concepts of cables made from HTS tape conductor and the development and test of prototype units, the final deliverable was successfully assembled at CERN in May 2013. This document reports on the activity that culminated with the assembly of the 20 m long HTS Superconducting Link.

  16. Self-assembly of colloidal surfactants

    Science.gov (United States)

    Kegel, Willem

    2012-02-01

    We developed colloidal dumbbells with a rough and a smooth part, based on a method reported in Ref. [1]. Specific attraction between the smooth parts occurs upon addition of non-adsorbing polymers of appropriate size. We present the first results in terms of the assemblies that emerge in these systems. [4pt] [1] D.J. Kraft, W.S. Vlug, C.M. van Kats, A. van Blaaderen, A. Imhof and W.K. Kegel, Self-assembly of colloids with liquid protrusions, J. Am. Chem. Soc. 131, 1182, (2009)

  17. Habitat filters in fungal endophyte community assembly

    Science.gov (United States)

    Fungal endophytes can influence host health, and more broadly, can instigate trophic cascades with effects scaling to the ecosystem level. Despite this, biotic mechanisms of endophyte community assembly are largely unknown. We used maize to investigate three potential habitat filters in endophyte co...

  18. DNA addition using linear self-assembly

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jian; QIAN LuLu; LIU Qiang; ZHANG ZhiZhou; HE Lin

    2007-01-01

    This paper presents a DNA algorithm which adds two nonnegative binary integers using self-assembly in constant steps. The approach has the benefit of greater experimental simplicity when compared with previous DNA addition algorithms. For the addition of two binary n-bit integers, O(n) is different from DNA strands and only O(1) biochemical experimental procedures are required.

  19. Molecular assembly in natural and engineered systems

    CERN Document Server

    Howorka, Stefan

    2011-01-01

    This volume explores some of the most exciting recent advances in basic research on molecular assembly in natural and engineered systems and how this knowledge is leading to advances in the various fields.* This series provides a forum for discussion of new discoveries, approaches, and ideas * Contributions from leading scholars and industry experts * Reference guide for researchers involved in molecular biology and related fields

  20. DPAL: Deductive Language for Embroidery Pattern Assembling

    Institute of Scientific and Technical Information of China (English)

    孟波; 郭磊; 陈世福

    2000-01-01

    This paper describes the design and implementation of DPA: a deductive language for embroidery pattern assembling. DPAL is similar to SQL and generates the embroidery pattern by matching the operators of space relation with the rule in rule database. It improves the production efficiency of embroidery drafts and increases the variety of colors and patterns.