WorldWideScience

Sample records for complex engineering silicones

  1. Engineered Adhesion Peptides for Improved Silicon Adsorption.

    Science.gov (United States)

    Ramakrishnan, Sathish Kumar; Jebors, Said; Martin, Marta; Cloitre, Thierry; Agarwal, Vivechana; Mehdi, Ahmad; Martinez, Jean; Subra, Gilles; Gergely, Csilla

    2015-11-01

    Engineering peptides that present selective recognition and high affinity for a material is a major challenge for assembly-driven elaboration of complex systems with wide applications in the field of biomaterials, hard-tissue regeneration, and functional materials for therapeutics. Peptide-material interactions are of vital importance in natural processes but less exploited for the design of novel systems for practical applications because of our poor understanding of mechanisms underlying these interactions. Here, we present an approach based on the synthesis of several truncated peptides issued from a silicon-specific peptide recovered via phage display technology. We use the photonic response provided by porous silicon microcavities to evaluate the binding efficiency of 14 different peptide derivatives. We identify and engineer a short peptide sequence (SLVSHMQT), revealing the highest affinity for p(+)-Si. The molecular recognition behavior of the obtained peptide fragment can be revealed through mutations allowing identification of the preferential affinity of certain amino acids toward silicon. These results constitute an advance in both the engineering of peptides that reveal recognition properties for silicon and the understanding of biomolecule-material interactions.

  2. Berger Engineering Complex

    Data.gov (United States)

    Federal Laboratory Consortium — Description/History: Engineering laboratory The Berger Lab Complex is a multi-purpose building with professional office, 100 seat auditorium, general purpose labs,...

  3. Engineering piezoresistivity using biaxially strained silicon

    DEFF Research Database (Denmark)

    Pedersen, Jesper Goor; Richter, Jacob; Brandbyge, Mads;

    2008-01-01

    We calculate the shear piezocoefficient of p-type silicon with grown-in biaxial strain using a 66 k·p method. We find a significant increase in the value of the shear piezocoefficient for compressive grown-in biaxial strain, while tensile strain decreases the piezocoefficient. The dependence...... of the piezocoefficient on temperature and dopant density is altered qualitatively for strained silicon. In particular, we find that a vanishing temperature coefficient may result for silicon with grown-in biaxial tensile strain. These results suggest that strained silicon may be used to engineer the iezoresistivity...

  4. Analytical and experimental evaluation of joining silicon carbide to silicon carbide and silicon nitride to silicon nitride for advanced heat engine applications Phase 2. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Sundberg, G.J.; Vartabedian, A.M.; Wade, J.A.; White, C.S. [Norton Co., Northboro, MA (United States). Advanced Ceramics Div.

    1994-10-01

    The purpose of joining, Phase 2 was to develop joining technologies for HIP`ed Si{sub 3}N{sub 4} with 4wt% Y{sub 2}O{sub 3} (NCX-5101) and for a siliconized SiC (NT230) for various geometries including: butt joins, curved joins and shaft to disk joins. In addition, more extensive mechanical characterization of silicon nitride joins to enhance the predictive capabilities of the analytical/numerical models for structural components in advanced heat engines was provided. Mechanical evaluation were performed by: flexure strength at 22 C and 1,370 C, stress rupture at 1,370 C, high temperature creep, 22 C tensile testing and spin tests. While the silicon nitride joins were produced with sufficient integrity for many applications, the lower join strength would limit its use in the more severe structural applications. Thus, the silicon carbide join quality was deemed unsatisfactory to advance to more complex, curved geometries. The silicon carbide joining methods covered within this contract, although not entirely successful, have emphasized the need to focus future efforts upon ways to obtain a homogeneous, well sintered parent/join interface prior to siliconization. In conclusion, the improved definition of the silicon carbide joining problem obtained by efforts during this contract have provided avenues for future work that could successfully obtain heat engine quality joins.

  5. Donor-hydrogen complexes in crystalline silicon

    NARCIS (Netherlands)

    Liang, Z.N.; Niesen, L; Haas, C; Denteneer, P.J.H.

    1996-01-01

    Experimental results are presented on the study of Sb-H complexes in crystalline silicon, employing Sb-119 --> Sn-119 source Mossbauer spectroscopy and a low-energy H implantation technique. In addition to a visible component, we observe a large decrease of the Mossbauer intensity associated with

  6. Donor-hydrogen complexes in crystalline silicon

    NARCIS (Netherlands)

    Liang, Z.N.; Niesen, L; Haas, C; Denteneer, P.J.H.

    1996-01-01

    Experimental results are presented on the study of Sb-H complexes in crystalline silicon, employing Sb-119 --> Sn-119 source Mossbauer spectroscopy and a low-energy H implantation technique. In addition to a visible component, we observe a large decrease of the Mossbauer intensity associated with th

  7. Joining and Integration of Silicon Carbide for Turbine Engine Applications

    Science.gov (United States)

    Halbig, Michael C.; Singh, Mrityunjay; Coddington, Bryan; Asthana, Rajiv

    2010-01-01

    The critical need for ceramic joining and integration technologies is becoming better appreciated as the maturity level increases for turbine engine components fabricated from ceramic and ceramic matrix composite materials. Ceramic components offer higher operating temperatures and reduced cooling requirements. This translates into higher efficiencies and lower emissions. For fabricating complex shapes, diffusion bonding of silicon carbide (SiC) to SiC is being developed. For the integration of ceramic parts to the surrounding metallic engine system, brazing of SiC to metals is being developed. Overcoming the chemical, thermal, and mechanical incompatibilities between dissimilar materials is very challenging. This presentation will discuss the types of ceramic components being developed by researchers and industry and the benefits of using ceramic components. Also, the development of strong, crack-free, stable bonds will be discussed. The challenges and progress in developing joining and integration approaches for a specific application, i.e. a SiC injector, will be presented.

  8. Research Update: Phonon engineering of nanocrystalline silicon thermoelectrics

    Science.gov (United States)

    Shiomi, Junichiro

    2016-10-01

    Nanocrystalline silicon thermoelectrics can be a solution to improve the cost-effectiveness of thermoelectric technology from both material and integration viewpoints. While their figure-of-merit is still developing, recent advances in theoretical/numerical calculations, property measurements, and structural synthesis/fabrication have opened up possibilities to develop the materials based on fundamental physics of phonon transport. Here, this is demonstrated by reviewing a series of works on nanocrystalline silicon materials using calculations of multiscale phonon transport, measurements of interfacial heat conduction, and synthesis from nanoparticles. Integration of these approaches allows us to engineer phonon transport to improve the thermoelectric performance by introducing local silicon-oxide structures.

  9. Modelling and engineering of stress based controlled oxidation effects for silicon nanostructure patterning

    Science.gov (United States)

    Han, Xiang-Lei; Larrieu, Guilhem; Krzeminski, Christophe

    2013-12-01

    Silicon nanostructure patterning with tight geometry control is an important challenge at the bottom level. In that context, stress based controlled oxidation appears to be an efficient tool for precise nanofabrication. Here, we investigate the stress-retarded oxidation phenomenon in various silicon nanostructures (nanobeams, nanorings and nanowires) at both the experimental and the theoretical levels. Different silicon nanostructures have been fabricated by a top-down approach. Complex dependence of the stress build-up on the nano-object’s dimension, shape and size has been demonstrated experimentally and physically explained by modelling. For the oxidation of a two-dimensional nanostructure (nanobeam), relative independence to size effects has been observed. On the other hand, radial stress increase with geometry downscaling of a one-dimensional nanostructure (nanowire) has been carefully emphasized. The study of shape engineering by retarded oxidation effects for vertical silicon nanowires is finally discussed.

  10. Light absorption engineering of hydrogenated nanocrystalline silicon by femtosecond laser.

    Science.gov (United States)

    Zheng, D Q; Ma, Y J; Xu, L; Su, W A; Ye, Q H; Oh, J I; Shen, W Z

    2012-09-01

    The light absorption coefficient of hydrogenated nanocrystalline silicon has been engineered to have a Gaussian distribution by means of absorption modification using a femtosecond laser. The absorption-modified sample exhibits a significant absorption enhancement of up to ∼700%, and the strong absorption does not depend on the incident light. We propose a model responsible for this interesting behavior. In addition, we present an optical limiter constructed through this absorption engineering method.

  11. Research Update: Phonon engineering of nanocrystalline silicon thermoelectrics

    Directory of Open Access Journals (Sweden)

    Junichiro Shiomi

    2016-10-01

    Full Text Available Nanocrystalline silicon thermoelectrics can be a solution to improve the cost-effectiveness of thermoelectric technology from both material and integration viewpoints. While their figure-of-merit is still developing, recent advances in theoretical/numerical calculations, property measurements, and structural synthesis/fabrication have opened up possibilities to develop the materials based on fundamental physics of phonon transport. Here, this is demonstrated by reviewing a series of works on nanocrystalline silicon materials using calculations of multiscale phonon transport, measurements of interfacial heat conduction, and synthesis from nanoparticles. Integration of these approaches allows us to engineer phonon transport to improve the thermoelectric performance by introducing local silicon-oxide structures.

  12. Thermo-acoustic engineering of silicon microresonators via evanescent waves

    Energy Technology Data Exchange (ETDEWEB)

    Tabrizian, R., E-mail: rtabrizi@umich.edu [Electrical Engineering and Computer Science Department, University of Michigan, Ann Arbor, Michigan 48109 (United States); Ayazi, F. [School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30308 (United States)

    2015-06-29

    A temperature-compensated silicon micromechanical resonator with a quadratic temperature characteristic is realized by acoustic engineering. Energy-trapped resonance modes are synthesized by acoustic coupling of propagating and evanescent extensional waves in waveguides with rectangular cross section. Highly different temperature sensitivity of propagating and evanescent waves is used to engineer the linear temperature coefficient of frequency. The resulted quadratic temperature characteristic has a well-defined turn-over temperature that can be tailored by relative energy distribution between propagating and evanescent acoustic fields. A 76 MHz prototype is implemented in single crystal silicon. Two high quality factor and closely spaced resonance modes, created from efficient energy trapping of extensional waves, are excited through thin aluminum nitride film. Having different evanescent wave constituents and energy distribution across the device, these modes show different turn over points of 67 °C and 87 °C for their quadratic temperature characteristic.

  13. Valley-engineered ultra-thin silicon for high-performance junctionless transistors

    Science.gov (United States)

    Kim, Seung-Yoon; Choi, Sung-Yool; Hwang, Wan Sik; Cho, Byung Jin

    2016-07-01

    Extremely thin silicon show good mechanical flexibility because of their 2-D like structure and enhanced performance by the quantum confinement effect. In this paper, we demonstrate a junctionless FET which reveals a room temperature quantum confinement effect (RTQCE) achieved by a valley-engineering of the silicon. The strain-induced band splitting and a quantum confinement effect induced from ultra-thin-body silicon are the two main mechanisms for valley engineering. These were obtained from the extremely well-controlled silicon surface roughness and high tensile strain in silicon, thereupon demonstrating a device mobility increase of ~500% in a 2.5 nm thick silicon channel device.

  14. Selective Synthesis of Manganese/Silicon Complexes in Supercritical Water

    Directory of Open Access Journals (Sweden)

    Jiancheng Wang

    2014-01-01

    Full Text Available A series of manganese salts (Mn(NO32, MnCl2, MnSO4, and Mn(Ac2 and silicon materials (silica sand, silica sol, and tetraethyl orthosilicate were used to synthesize Mn/Si complexes in supercritical water using a tube reactor. X-ray diffraction (XRD, X-ray photoelectron spectrometer (XPS, transmission electron microscopy (TEM, and scanning electron microscopy (SEM were employed to characterize the structure and morphology of the solid products. It was found that MnO2, Mn2O3, and Mn2SiO4 could be obtained in supercritical water at 673 K in 5 minutes. The roles of both anions of manganese salts and silicon species in the formation of manganese silicon complexes were discussed. The inorganic manganese salt with the oxyacid radical could be easily decomposed to produce MnO2/SiO2 and Mn2O3/SiO2. It is interesting to found that Mn(Ac2 can react with various types of silicon to produce Mn2SiO4. The hydroxyl groups of the SiO2 surface from different silicon sources enhance the reactivity of SiO2.

  15. Inverse design engineering of all-silicon polarization beam splitters

    DEFF Research Database (Denmark)

    Frandsen, Lars Hagedorn; Sigmund, Ole

    2016-01-01

    Utilizing the inverse design engineering method of topology optimization, we have realized high-performing all-silicon ultra-compact polarization beam splitters. We show that the device footprint of the polarization beam splitter can be as compact as similar to 2 µm2 while performing experimentally...... with a polarization splitting loss lower than similar to 0.82 dB and an extinction ratio larger than similar to 15 dB in the C-band. We investigate the device performance as a function of the device length and find a lower length above which the performance only increases incrementally. Imposing a minimum feature...

  16. DLTS analysis of nickel-hydrogen complex defects in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Shiraishi, M. [Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany)]|[Sony Corporation Research Center, 174 Fujitsuka-cho, Hodogaya-ku, Yokohama 240 (Japan); Sachse, J.-U.; Weber, J. [Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany); Lemke, H. [TU Berlin, Institut fuer Werkstoffe der Elektronik, Jebensstrasse 1, D-10623, Berlin (Germany)

    1999-02-12

    The results of a deep level transient spectroscopy (DLTS) study of nickel-hydrogen complexes in n- and p-type silicon are presented. Hydrogen is incorporated by wet-chemical etching. After etching, eleven electrically active Ni-H related levels are observed. Heat treatment enables us to investigate the thermal stability of Ni-H complexes. Possible structures of the Ni-H defects are proposed. (orig.) 10 refs.

  17. Integration of functional complex oxide nanomaterials on silicon

    Directory of Open Access Journals (Sweden)

    Jose Manuel eVila-Fungueiriño

    2015-06-01

    Full Text Available The combination of standard wafer-scale semiconductor processing with the properties of functional oxides opens up to innovative and more efficient devices with high value applications that can be produced at large scale. This review uncovers the main strategies that are successfully used to monolithically integrate functional complex oxide thin films and nanostructures on silicon: the chemical solution deposition approach (CSD and the advanced physical vapor deposition techniques such as oxide molecular beam epitaxy (MBE. Special emphasis will be placed on complex oxide nanostructures epitaxially grown on silicon using the combination of CSD and MBE. Several examples will be exposed, with a particular stress on the control of interfaces and crystallization mechanisms on epitaxial perovskite oxide thin films, nanostructured quartz thin films, and octahedral molecular sieve nanowires. This review enlightens on the potential of complex oxide nanostructures and the combination of both chemical and physical elaboration techniques for novel oxide-based integrated devices.

  18. Rock engineering: La Grande Complex, Quebec

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, D.K.; Levay, J.

    1982-08-01

    The paper presents an overview of rock engineering considerations in the Complex as related particularly to excavation and support problems. Examples are chosen to show the range of geological conditions encountered together with the engineering philosophy that has governed their treatment. Experience gained with unlined tunnels and channels for hydraulic purposes is discussed.

  19. Metasynthetic computing and engineering of complex systems

    CERN Document Server

    Cao, Longbing

    2015-01-01

    Provides a comprehensive overview and introduction to the concepts, methodologies, analysis, design and applications of metasynthetic computing and engineering. The author: Presents an overview of complex systems, especially open complex giant systems such as the Internet, complex behavioural and social problems, and actionable knowledge discovery and delivery in the big data era. Discusses ubiquitous intelligence in complex systems, including human intelligence, domain intelligence, social intelligence, network intelligence, data intelligence and machine intelligence, and their synergy thro

  20. Collaborative engineering for complex products

    CSIR Research Space (South Africa)

    Erasmus, J

    2015-10-01

    Full Text Available stream_source_info Erasmus_2015.pdf.txt stream_content_type text/plain stream_size 6206 Content-Encoding UTF-8 stream_name Erasmus_2015.pdf.txt Content-Type text/plain; charset=UTF-8 Collaborative engineering... • Only viable means of beneficiating natural resources in SA Current situation Competitiveness of manufacturing in SA has dramatically decreased [1] NIPF: Manufacturing drives employment and growth in the economy [2] IPAP: 16 industry sectors...

  1. Complex engineering systems science meets technology

    CERN Document Server

    Minai, Ali A; Bar-Yam, Yaneer

    2006-01-01

    Every time that we take money out of an ATM, surf the internet or simply turn on a light switch, we enjoy the benefits of complex engineered systems. Systems like power grids and global communication networks are so ubiquitous in our daily lives that we usually take them for granted, only noticing them when they break down. But how do such amazing technologies and infrastructures come to be what they are? How are these systems designed? How do distributed networks work? How are they made to respond rapidly in 'real time'? And as the demands that we place on these systems become increasingly complex, are traditional systems-engineering practices still relevant? This volume examines the difficulties that arise in creating highly complex engineered systems and new approaches that are being adopted. Topics addressed range from the formal representation and classification of distributed networked systems to revolutionary engineering practices inspired by biological evolution. By bringing together the latest resear...

  2. Base Transport and Vertical Profile Engineering in SILICON/SILICON(1-X) Germanium(x)/silicon Heterojunction Bipolar Transistors

    Science.gov (United States)

    Prinz, Erwin Josef

    1992-01-01

    Recent advances in low-temperature epitaxial growth of strained silicon-germanium alloys on silicon substrates allow bandgap engineering in silicon-based devices, with profound consequences for device design. In this thesis the improved control by Rapid Thermal Chemical Vapor Deposition of the vertical profile of a Si/Si_{1-x}Ge _{x}/Si heterojunction bipolar transistor (HBT) is used to study the effect of the shape of the conduction band in the base on device performance. Near-ideal base currents in Si/Si_ {1-x}Ge_{x}/Si HBT's, limited by hole injection into the emitter, are achieved using a non-ultra-high vacuum (UHV) technique for the first time, proving that high-lifetime Si_{1-x}Ge _{x} material can be fabricated using processes compatible with standard silicon technology. Graded-base Si/Si_{1-x}Ge_{x} /Si HBT's are fabricated in a non-UHV epitaxial technology for the first time, and their electrical characteristics are modeled analytically. The formation of parasitic potential barriers for electrons in the base of HBT's resulting from base dopant outdiffusion or non-abrupt interfaces is studied, together with the concurrent degradation of the electrical performance of the devices. This deleterious effect is especially severe in devices with narrow, heavily doped bases fabricated in an integrated circuit (IC) process because of the thermal budget employed. To alleviate this problem, intrinsic Si_{1-x}Ge_{x}^acer layers can be inserted on both sides of the base to greatly improve device performance. The tradeoff between the common-emitter current gain beta and the Early voltage V_{A} (output resistance) in heterojunction bipolar transistors is investigated for the first time. This tradeoff is important for analog application of HBT's, and it is shown that thin, narrow -gap layers in the base close to the base-collector junction reduce the Early effect dramatically leading to a high Early voltage. It is further demonstrated that even small amounts of dopant

  3. Complexity management in engineering design a primer

    CERN Document Server

    Maurer, Maik

    2017-01-01

    The treatise supports understanding the phenomena of complexity in engineering, distinguishes complexity from other challenges and presents an overview of definitions and applied approaches. The historical background of complexity management is explained by highlighting the important epochs, their key actors and their discoveries, findings and developments. Knowing about the appearance of early system awareness in ancient Greece, the creation of mechanical philosophy in the 17th century and the discovery of classic physics enables the reader to better comprehend modern system sciences and management approaches. A classification of complexity management approaches by research fields indicates current focus areas and starting points for future discussions. In a comprehensive map, the classification points out mutual overlaps between engineering disciplines in terms of similar complexity management approaches. Finally, the treatise introduces a generic complexity management framework, which is based on structura...

  4. Inverse design engineering of all-silicon polarization beam splitters

    DEFF Research Database (Denmark)

    Frandsen, Lars Hagedorn; Sigmund, Ole

    2016-01-01

    Utilizing the inverse design engineering method of topology optimization, we have realized high-performing all-silicon ultra-compact polarization beam splitters. We show that the device footprint of the polarization beam splitter can be as compact as similar to 2 µm2 while performing experimentally...... with a polarization splitting loss lower than similar to 0.82 dB and an extinction ratio larger than similar to 15 dB in the C-band. We investigate the device performance as a function of the device length and find a lower length above which the performance only increases incrementally. Imposing a minimum feature...... size constraint in the optimization is shown to affect the performance negatively and reveals the necessity for light to scatter on a sub-wavelength scale to obtain functionalities in compact photonic devices....

  5. Interface engineering of Graphene-Silicon heterojunction solar cells

    Science.gov (United States)

    Xu, Dikai; Yu, Xuegong; Yang, Lifei; Yang, Deren

    2016-11-01

    Graphene has attracted great research interests due to its unique mechanical, electrical and optical properties, which opens up a huge number of opportunities for applications. Recently, Graphene-Silicon (Grsbnd Si) solar cell has been recognized as one interesting candidate for the future photovoltaic. Since the first Grsbnd Si solar cell reported in 2010, Grsbnd Si solar cell has been intensively investigated and the power converse efficiency (PCE) of it has been developed to 15.6%. This review presents and discusses current development of Grsbnd Si solar cell. Firstly, the basic concept and mechanism of Grsbnd Si solar cell are introduced. Then, several key technologies are introduced to improve the performance of Grsbnd Si solar cells, such as chemical doping, annealing, Si surface passivation and interlayer insertion. Particular emphasis is placed on strategies for Grsbnd Si interface engineering. Finally, new pathways and opportunities of "MIS-like structure" Grsbnd Si solar cells are described.

  6. Complex intermetallic phase in multicrystalline silicon doped withtransition metals

    Energy Technology Data Exchange (ETDEWEB)

    Heuer, Matthias; Buonassisi, Tonio; Marcus, Matthew A.; Istratov,Andrei A.; Pickett, Matthew D.; Shibata, Tomohiro; Weber, Eicke R.

    2006-01-01

    We report the observation of an alloy phase with fluorite-type structure containing Ni, Fe, Cu, and Si, found as precipitates in multi-crystalline silicon. The analysis of extended x-ray absorption fine-structure microspectroscopy ({micro}-EXAFS) measurements on the K edges of the transition metals of the precipitates and a synthetic reference material with composition of Ni{sub 0.82}Fe{sub 0.21}Cu{sub 0.02}Si{sub 1.94} support a structure model similar to NiSi{sub 2} but with mixed occupancies of Fe on the Ni site and Cu on the Si site. This observation provides evidence that transition metals interact during precipitation within silicon and form complex silicides.

  7. Engineering Complex Systems: Multiscale Analysis and Evolutionary Engineering

    Science.gov (United States)

    Bar-Yam, Yaneer

    We describe an analytic approach, multiscale analysis, that can demonstrate the fundamental limitations of decomposition based engineering for the development of highly complex systems. The interdependence of components and communication between design teams limits any planning based process. Recognizing this limitation, we found that a new strategy for constructing many highly complex systems should be modeled after biological evolution, or market economies, where multiple design efforts compete in parallel for adoption through testing in actual use. Evolution is the only process that is known to create highly complex systems.

  8. Comparative Analysis of VNSA Complex Engineering Efforts

    Directory of Open Access Journals (Sweden)

    Gary Ackerman

    2016-03-01

    Full Text Available The case studies undertaken in this special issue demonstrate unequivocally that, despite being forced to operate clandestinely and facing the pressures of security forces seeking to hunt them down and neutralize them, at least a subset of violent non-state actors (VNSAs are capable of some genuinely impressive feats of engineering. At the same time, success in such endeavours is not guaranteed and VNSAs will undoubtedly face a number of obstacles along the way. A comparative analysis of the cases also reveals new insights about the factors influencing the decision to pursue complex engineering efforts, the implementation of such decisions and the determinants of the ultimate outcome. These result in a set of hypotheses and indicators that, if confirmed by future research, can contribute to both operational and strategic intelligence assessments. Overall, the current study enriches our understanding of how and why VNSAs might engage in complex engineering efforts.

  9. Engineering Education as a Complex System

    Science.gov (United States)

    Gattie, David K.; Kellam, Nadia N.; Schramski, John R.; Walther, Joachim

    2011-01-01

    This paper presents a theoretical basis for cultivating engineering education as a complex system that will prepare students to think critically and make decisions with regard to poorly understood, ill-structured issues. Integral to this theoretical basis is a solution space construct developed and presented as a benchmark for evaluating…

  10. PREPARATION AND CHARACTERIZATION OF SOME SILICON (IV COMPLEXES

    Directory of Open Access Journals (Sweden)

    Z.F DAWOOD

    2008-06-01

    Full Text Available Silicon(IV complexes containing mixed ligands: Shiff-bases (AH {derived from 2- or 3- amino-pyridine with 2-hydroxy- or 3-me- thoxy- or 2-hydroxy-3-methoxy-benzaldehyde} and benzalde- hyde semicarbazone (BSCH, have been prepared. The resulted complexes have been characterized by elemental analysis, molar conductance values, infrared and electronic spectral data. Complexes of the type [Si(BSCH2(AH]Cl4, [Si(BSC2(AnH]Cl2 and [Si(BSC2(A]Cl (where n=2 or 3, A=deprotonated Schiff-base ligands , BSC= deprotonated semicarbazone have been proposed in neutral and basic medium, respectively.

  11. Complex of heavy magnetic ions and luminescent silicon nanoparticles

    Science.gov (United States)

    Hoang, Tuan

    We study the optical properties of luminescent silicon nanoparticles in the presence of magnetic ions of iron or erbium in solution and electric biasing. Upon the introduction of the ions under zero biasing, the luminescence is enhanced to by 50%. The peak position of the nanoparticle's spectrum shifts by 10 nm. The enhancement remains stable even outside of the solvent, and under exposure to an ionizing environment, with electric eld as high as 8 MV/m exceeding the breakdown eld value of solution. We attribute the enhancement and spectral change to the formation of complex between the silicon nanoparticles and the ions. We compare these results with the computational study that was done in our group using density functional theory. The calculations yield two stable con gurations that such ion-particle complex could form, with binding energy of 0:49 eV between the ion and the nanoparticle. The complexes promise diverse applications in magnetic/optical imaging, spatially programmable deposition, spin-based memories and transistors, infrared communications, ltration, as well as interplanetary and interstellar observation and modeling.

  12. Advanced Engineering Strategies for Periodontal Complex Regeneration

    Directory of Open Access Journals (Sweden)

    Chan Ho Park

    2016-01-01

    Full Text Available The regeneration and integration of multiple tissue types is critical for efforts to restore the function of musculoskeletal complex. In particular, the neogenesis of periodontal constructs for systematic tooth-supporting functions is a current challenge due to micron-scaled tissue compartmentalization, oblique/perpendicular orientations of fibrous connective tissues to the tooth root surface and the orchestration of multiple regenerated tissues. Although there have been various biological and biochemical achievements, periodontal tissue regeneration remains limited and unpredictable. The purpose of this paper is to discuss current advanced engineering approaches for periodontal complex formations; computer-designed, customized scaffolding architectures; cell sheet technology-based multi-phasic approaches; and patient-specific constructs using bioresorbable polymeric material and 3-D printing technology for clinical application. The review covers various advanced technologies for periodontal complex regeneration and state-of-the-art therapeutic avenues in periodontal tissue engineering.

  13. Lessons Learned from Crowdsourcing Complex Engineering Tasks.

    Science.gov (United States)

    Staffelbach, Matthew; Sempolinski, Peter; Kijewski-Correa, Tracy; Thain, Douglas; Wei, Daniel; Kareem, Ahsan; Madey, Gregory

    2015-01-01

    Crowdsourcing is the practice of obtaining needed ideas, services, or content by requesting contributions from a large group of people. Amazon Mechanical Turk is a web marketplace for crowdsourcing microtasks, such as answering surveys and image tagging. We explored the limits of crowdsourcing by using Mechanical Turk for a more complicated task: analysis and creation of wind simulations. Our investigation examined the feasibility of using crowdsourcing for complex, highly technical tasks. This was done to determine if the benefits of crowdsourcing could be harnessed to accurately and effectively contribute to solving complex real world engineering problems. Of course, untrained crowds cannot be used as a mere substitute for trained expertise. Rather, we sought to understand how crowd workers can be used as a large pool of labor for a preliminary analysis of complex data. We compared the skill of the anonymous crowd workers from Amazon Mechanical Turk with that of civil engineering graduate students, making a first pass at analyzing wind simulation data. For the first phase, we posted analysis questions to Amazon crowd workers and to two groups of civil engineering graduate students. A second phase of our experiment instructed crowd workers and students to create simulations on our Virtual Wind Tunnel website to solve a more complex task. With a sufficiently comprehensive tutorial and compensation similar to typical crowd-sourcing wages, we were able to enlist crowd workers to effectively complete longer, more complex tasks with competence comparable to that of graduate students with more comprehensive, expert-level knowledge. Furthermore, more complex tasks require increased communication with the workers. As tasks become more complex, the employment relationship begins to become more akin to outsourcing than crowdsourcing. Through this investigation, we were able to stretch and explore the limits of crowdsourcing as a tool for solving complex problems.

  14. Lessons Learned from Crowdsourcing Complex Engineering Tasks.

    Directory of Open Access Journals (Sweden)

    Matthew Staffelbach

    Full Text Available Crowdsourcing is the practice of obtaining needed ideas, services, or content by requesting contributions from a large group of people. Amazon Mechanical Turk is a web marketplace for crowdsourcing microtasks, such as answering surveys and image tagging. We explored the limits of crowdsourcing by using Mechanical Turk for a more complicated task: analysis and creation of wind simulations.Our investigation examined the feasibility of using crowdsourcing for complex, highly technical tasks. This was done to determine if the benefits of crowdsourcing could be harnessed to accurately and effectively contribute to solving complex real world engineering problems. Of course, untrained crowds cannot be used as a mere substitute for trained expertise. Rather, we sought to understand how crowd workers can be used as a large pool of labor for a preliminary analysis of complex data.We compared the skill of the anonymous crowd workers from Amazon Mechanical Turk with that of civil engineering graduate students, making a first pass at analyzing wind simulation data. For the first phase, we posted analysis questions to Amazon crowd workers and to two groups of civil engineering graduate students. A second phase of our experiment instructed crowd workers and students to create simulations on our Virtual Wind Tunnel website to solve a more complex task.With a sufficiently comprehensive tutorial and compensation similar to typical crowd-sourcing wages, we were able to enlist crowd workers to effectively complete longer, more complex tasks with competence comparable to that of graduate students with more comprehensive, expert-level knowledge. Furthermore, more complex tasks require increased communication with the workers. As tasks become more complex, the employment relationship begins to become more akin to outsourcing than crowdsourcing. Through this investigation, we were able to stretch and explore the limits of crowdsourcing as a tool for solving complex

  15. Optimization strategies for complex engineering applications

    Energy Technology Data Exchange (ETDEWEB)

    Eldred, M.S.

    1998-02-01

    LDRD research activities have focused on increasing the robustness and efficiency of optimization studies for computationally complex engineering problems. Engineering applications can be characterized by extreme computational expense, lack of gradient information, discrete parameters, non-converging simulations, and nonsmooth, multimodal, and discontinuous response variations. Guided by these challenges, the LDRD research activities have developed application-specific techniques, fundamental optimization algorithms, multilevel hybrid and sequential approximate optimization strategies, parallel processing approaches, and automatic differentiation and adjoint augmentation methods. This report surveys these activities and summarizes the key findings and recommendations.

  16. Shape-engineered multifunctional porous silicon nanoparticles by direct imprinting.

    Science.gov (United States)

    Mares, Jeremy W; Fain, Joshua S; Beavers, Kelsey R; Duvall, Craig L; Weiss, Sharon M

    2015-07-10

    A versatile and scalable method for fabricating shape-engineered nano- and micrometer scale particles from mesoporous silicon (PSi) thin films is presented. This approach, based on the direct imprinting of porous substrates (DIPS) technique, facilitates the generation of particles with arbitrary shape, ranging in minimum dimension from approximately 100 nm to several micrometers, by carrying out high-pressure (>200 MPa) direct imprintation, followed by electrochemical etching of a sub-surface perforation layer and ultrasonication. PSi particles (PSPs) with a variety of geometries have been produced in quantities sufficient for biomedical applications (≫10 μg). Because the stamps can be reused over 150 times, this process is substantially more economical and efficient than the use of electron beam lithography and reactive ion etching for the fabrication of nanometer-scale PSPs directly. The versatility of this fabrication method is demonstrated by loading the DIPS-imprinted PSPs with a therapeutic peptide nucleic acid drug molecule, and by vapor deposition of an Au coating to facilitate the use of PSPs as a photothermal contrast agent.

  17. Strong Photoluminescence Enhancement of Silicon Oxycarbide through Defect Engineering

    Directory of Open Access Journals (Sweden)

    Brian Ford

    2017-04-01

    Full Text Available The following study focuses on the photoluminescence (PL enhancement of chemically synthesized silicon oxycarbide (SiCxOy thin films and nanowires through defect engineering via post-deposition passivation treatments. SiCxOy materials were deposited via thermal chemical vapor deposition (TCVD, and exhibit strong white light emission at room-temperature. Post-deposition passivation treatments were carried out using oxygen, nitrogen, and forming gas (FG, 5% H2, 95% N2 ambients, modifying the observed white light emission. The observed white luminescence was found to be inversely related to the carbonyl (C=O bond density present in the films. The peak-to-peak PL was enhanced ~18 and ~17 times for, respectively, the two SiCxOy matrices, oxygen-rich and carbon-rich SiCxOy, via post-deposition passivations. Through a combinational and systematic Fourier transform infrared spectroscopy (FTIR and PL study, it was revealed that proper tailoring of the passivations reduces the carbonyl bond density by a factor of ~2.2, corresponding to a PL enhancement of ~50 times. Furthermore, the temperature-dependent and temperature-dependent time resolved PL (TDPL and TD-TRPL behaviors of the nitrogen and forming gas passivated SiCxOy thin films were investigated to acquire further insight into the ramifications of the passivation on the carbonyl/dangling bond density and PL yield.

  18. Morphogenetic Engineering Toward Programmable Complex Systems

    CERN Document Server

    Sayama, Hiroki; Michel, Olivier

    2012-01-01

    Generally, spontaneous pattern formation phenomena are random and repetitive, whereas elaborate devices are the deterministic product of human design. Yet, biological organisms and collective insect constructions are exceptional examples of complex systems that are both self-organized and architectural.   This book is the first initiative of its kind toward establishing a new field of research, Morphogenetic Engineering, to explore the modeling and implementation of “self-architecturing” systems. Particular emphasis is placed on the programmability and computational abilities of self-organization, properties that are often underappreciated in complex systems science—while, conversely, the benefits of self-organization are often underappreciated in engineering methodologies.   Altogether, the aim of this work is to provide a framework for and examples of a larger class of “self-architecturing” systems, while addressing fundamental questions such as   > How do biological organisms carry out morphog...

  19. Risk calculation method for complex engineering system

    Directory of Open Access Journals (Sweden)

    Li-ping WANG

    2011-09-01

    Full Text Available This paper presents a rapid and simple risk calculation method for large and complex engineering systems, the simulated maximum entropy method (SMEM, which is based on integration of the advantages of the Monte Carlo and maximum entropy methods, thus avoiding the shortcoming of the slow convergence rate of the Monte Carlo method in risk calculation. Application of SMEM in the calculation of reservoir flood discharge risk shows that this method can make full use of the known information under the same conditions and obtain the corresponding probability distribution and the risk value. It not only greatly improves the speed, compared with the Monte Carlo method, but also provides a new approach for the risk calculation in large and complex engineering systems.

  20. Genetic code expansion for multiprotein complex engineering.

    Science.gov (United States)

    Koehler, Christine; Sauter, Paul F; Wawryszyn, Mirella; Girona, Gemma Estrada; Gupta, Kapil; Landry, Jonathan J M; Fritz, Markus Hsi-Yang; Radic, Ksenija; Hoffmann, Jan-Erik; Chen, Zhuo A; Zou, Juan; Tan, Piau Siong; Galik, Bence; Junttila, Sini; Stolt-Bergner, Peggy; Pruneri, Giancarlo; Gyenesei, Attila; Schultz, Carsten; Biskup, Moritz Bosse; Besir, Hueseyin; Benes, Vladimir; Rappsilber, Juri; Jechlinger, Martin; Korbel, Jan O; Berger, Imre; Braese, Stefan; Lemke, Edward A

    2016-12-01

    We present a baculovirus-based protein engineering method that enables site-specific introduction of unique functionalities in a eukaryotic protein complex recombinantly produced in insect cells. We demonstrate the versatility of this efficient and robust protein production platform, 'MultiBacTAG', (i) for the fluorescent labeling of target proteins and biologics using click chemistries, (ii) for glycoengineering of antibodies, and (iii) for structure-function studies of novel eukaryotic complexes using single-molecule Förster resonance energy transfer as well as site-specific crosslinking strategies.

  1. Engineered silicon ring resonator for wavelength multiplexed photon-pair generation

    CERN Document Server

    Mazeas, Florent; Bentivegna, Marco; Kaiser, Florian; Aktas, Djeylan; Zhang, Weiwei; Ramos, Carlos Alonso; Bin-Ngah, Lutfi-Arif; Lunghi, Tommaso; Picholle, Éric; Belabas-Plougonven, Nadia; Roux, Xavier Le; Cassan, Éric; Marris-Morini, Delphine; Vivien, Laurent; Sauder, Grégory; Labonté, Laurent; Tanzilli, Sébastien

    2016-01-01

    We report an efficient energy-time entangled photon-pair source based on four-wave mixing in a CMOS-compatible silicon photonics ring resonator. Thanks to suitable optimization, the source shows a large spectral brightness of 400 pairs of entangled photons /s/MHz for 500 {\\mu}W pump power. Additionally, the resonator has been engineered so as to generate a frequency comb structure compatible with standard telecom dense wavelength division multiplexers. We demonstrate high-purity energy-time entanglement, i.e., free of photonic noise, with near perfect raw visibilities (> 98%) between various channel pairs in the telecom C-band. Such a compact source stands as a path towards more complex quantum photonic circuits dedicated to quantum communication systems.

  2. Electrical studies of Fe-related defect complexes in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Chi Kwong

    2012-09-15

    Iron (Fe) is an important impurity in solar-grade silicon which contributes substantially in degrading the efficiency of solar cells. The degradation is mainly caused by the Fe atoms situating at an unperturbed tetrahedral interstitial sites (Fei) in the silicon crystal, consequently acting as a recombination center. By altering the position and the neighbouring environment at which the Fe atoms reside, there are opportunities in minimizing or neutralizing the electrical activity of Fe. Furthermore, utilizing the high mobility of Fe, one can increase the performance of a device by accumulating the Fe atoms from critical regions into regions where Fe can be tolerated. These approaches can help in realizing high efficient solar cells based on cheap and highly Fe-contaminated silicon. In this work, we have investigated the interaction between Fe and defects relevant to solar cells, using mainly electrical characterization methods such as capacitance-voltage measurement, deep level transient spectroscopy and admittance spectroscopy. From the study of potential hydrogen passivation of Fe, hydrogen was introduced through wet chemical etching and further driven to a defined region. Using depth profiles, it is found that incorporation of hydrogen stimulates the dissociation of the iron-boron (Fe-B) pair, releasing and resulting in the unwanted Fei. At the same time, no passivation of Fe by hydrogen has been observed. On the investigation of the mechanism of phosphorus gettering of metal impurities, vacancies have been generated through proton-irradiation. The resulting irradiation-induced defects were examined for reactions with Fe after heat treatments. Based on the evolution of defect concentrations by isochronal annealings, it is found that Fe interacts with the divacancy and the vacancy-oxygen complexes, forming deep levels of 0.28 eV and 0.34 eV above the valence band edge (EV), respectively. In the search for substitutional Fe to investigate its electrical activity

  3. 3D bioprinting for engineering complex tissues.

    Science.gov (United States)

    Mandrycky, Christian; Wang, Zongjie; Kim, Keekyoung; Kim, Deok-Ho

    2016-01-01

    Bioprinting is a 3D fabrication technology used to precisely dispense cell-laden biomaterials for the construction of complex 3D functional living tissues or artificial organs. While still in its early stages, bioprinting strategies have demonstrated their potential use in regenerative medicine to generate a variety of transplantable tissues, including skin, cartilage, and bone. However, current bioprinting approaches still have technical challenges in terms of high-resolution cell deposition, controlled cell distributions, vascularization, and innervation within complex 3D tissues. While no one-size-fits-all approach to bioprinting has emerged, it remains an on-demand, versatile fabrication technique that may address the growing organ shortage as well as provide a high-throughput method for cell patterning at the micrometer scale for broad biomedical engineering applications. In this review, we introduce the basic principles, materials, integration strategies and applications of bioprinting. We also discuss the recent developments, current challenges and future prospects of 3D bioprinting for engineering complex tissues. Combined with recent advances in human pluripotent stem cell technologies, 3D-bioprinted tissue models could serve as an enabling platform for high-throughput predictive drug screening and more effective regenerative therapies.

  4. Engineering Complex Orthopaedic Tissues via Strategic Biomimicry

    Science.gov (United States)

    Qu, Dovina; Mosher, Christopher Z.; Boushell, Margaret K.; Lu, Helen H.

    2014-01-01

    The primary current challenge in regenerative engineering resides in the simultaneous formation of more than one type of tissue, as well as their functional assembly into complex tissues or organ systems. Tissue-tissue synchrony is especially important in the musculoskeletal system, whereby overall organ function is enabled by the seamless integration of bone with soft tissues such as ligament, tendon, or cartilage, as well as the integration of muscle with tendon. Therefore, in lieu of a traditional single-tissue system (e.g. bone, ligament), composite tissue scaffold designs for the regeneration of functional connective tissue units (e.g. bone-ligament-bone) are being actively investigated. Closely related is the effort to re-establish tissue-tissue interfaces, which is essential for joining these tissue building blocks and facilitating host integration. Much of the research at the forefront of the field has centered on bioinspired stratified or gradient scaffold designs which aim to recapitulate the structural and compositional inhomogeneity inherent across distinct tissue regions. As such, given the complexity of these musculoskeletal tissue units, the key question is how to identify the most relevant parameters for recapitulating the native structure-function relationships in the scaffold design. Therefore, the focus of this review, in addition to presenting the state-of-the-art in complex scaffold design, is to explore how strategic biomimicry can be applied in engineering tissue connectivity. The objective of strategic biomimicry is to avoid over-engineering by establishing what needs to be learned from nature and defining the essential matrix characteristics that must be reproduced in scaffold design. Application of this engineering strategy for the regeneration of the most common musculoskeletal tissue units (e.g. bone-ligament-bone, muscle-tendon-bone, cartilage-bone) will be discussed in this review. It is anticipated that these exciting efforts will

  5. Engineering complex orthopaedic tissues via strategic biomimicry.

    Science.gov (United States)

    Qu, Dovina; Mosher, Christopher Z; Boushell, Margaret K; Lu, Helen H

    2015-03-01

    The primary current challenge in regenerative engineering resides in the simultaneous formation of more than one type of tissue, as well as their functional assembly into complex tissues or organ systems. Tissue-tissue synchrony is especially important in the musculoskeletal system, wherein overall organ function is enabled by the seamless integration of bone with soft tissues such as ligament, tendon, or cartilage, as well as the integration of muscle with tendon. Therefore, in lieu of a traditional single-tissue system (e.g., bone, ligament), composite tissue scaffold designs for the regeneration of functional connective tissue units (e.g., bone-ligament-bone) are being actively investigated. Closely related is the effort to re-establish tissue-tissue interfaces, which is essential for joining these tissue building blocks and facilitating host integration. Much of the research at the forefront of the field has centered on bioinspired stratified or gradient scaffold designs which aim to recapitulate the structural and compositional inhomogeneity inherent across distinct tissue regions. As such, given the complexity of these musculoskeletal tissue units, the key question is how to identify the most relevant parameters for recapitulating the native structure-function relationships in the scaffold design. Therefore, the focus of this review, in addition to presenting the state-of-the-art in complex scaffold design, is to explore how strategic biomimicry can be applied in engineering tissue connectivity. The objective of strategic biomimicry is to avoid over-engineering by establishing what needs to be learned from nature and defining the essential matrix characteristics that must be reproduced in scaffold design. Application of this engineering strategy for the regeneration of the most common musculoskeletal tissue units (e.g., bone-ligament-bone, muscle-tendon-bone, cartilage-bone) will be discussed in this review. It is anticipated that these exciting efforts will

  6. Modelling methodology for engineering of complex sociotechnical systems

    CSIR Research Space (South Africa)

    Oosthuizen, R

    2014-10-01

    Full Text Available Different systems engineering techniques and approaches are applied to design and develop complex sociotechnical systems for complex problems. In a complex sociotechnical system cognitive and social humans use information technology to make sense...

  7. Temperature-dependent photoluminescence of surface-engineered silicon nanocrystals

    Science.gov (United States)

    Mitra, Somak; Švrček, Vladimir; Macias-Montero, Manual; Velusamy, Tamilselvan; Mariotti, Davide

    2016-01-01

    In this work we report on temperature-dependent photoluminescence measurements (15–300 K), which have allowed probing radiative transitions and understanding of the appearance of various transitions. We further demonstrate that transitions associated with oxide in SiNCs show characteristic vibronic peaks that vary with surface characteristics. In particular we study differences and similarities between silicon nanocrystals (SiNCs) derived from porous silicon and SiNCs that were surface-treated using a radio-frequency (RF) microplasma system. PMID:27296771

  8. Fostering creative engineers: a key to face the complexity of engineering practice

    Science.gov (United States)

    Zhou, Chunfang

    2012-08-01

    Recent studies have argued a shift of thinking about engineering practice from a linear conception to a system understanding. The complexity of engineering practice has been thought of as the root of challenges for engineers. Moreover, creativity has been emphasised as one key capability that engineering students should master. This paper aims to illustrate deeply why engineering education needs to foster creative students to face the challenges of complex engineering work. So a literature review will be provided by focusing on the necessity of developing creativity in engineering education. As the literature demonstrates, this paper reveals the understanding of complexity in engineering practice and the roles of creativity in engineering practice. In addition, the barriers to creativity in current engineering education and some implications of pedagogic strategies will be discussed. So this paper contributes to rethinking the engineering profession in a social context and a link between creativity research and engineering education.

  9. Dispersion engineering silicon nitride waveguides for broadband nonlinear frequency conversion

    NARCIS (Netherlands)

    Epping, J.P.

    2015-01-01

    In this thesis, we investigated nonlinear frequency conversion of optical wavelengths using integrated silicon nitride (Si3N4) waveguides. Two nonlinear conversion schemes were considered: seeded four-wave mixing and supercontinuum generation. The first—seeded four-wave mixing—is investigated by a n

  10. The chemistry of silicon

    CERN Document Server

    Rochow, E G; Emeléus, H J; Nyholm, Ronald

    1975-01-01

    Pergamon Texts in Organic Chemistry, Volume 9: The Chemistry of Silicon presents information essential in understanding the chemical properties of silicon. The book first covers the fundamental aspects of silicon, such as its nuclear, physical, and chemical properties. The text also details the history of silicon, its occurrence and distribution, and applications. Next, the selection enumerates the compounds and complexes of silicon, along with organosilicon compounds. The text will be of great interest to chemists and chemical engineers. Other researchers working on research study involving s

  11. Defects and impurities in silicon materials an introduction to atomic-level silicon engineering

    CERN Document Server

    Langouche, Guido

    2015-01-01

    This book emphasizes the importance of the fascinating atomistic insights into the defects and the impurities as well as the dynamic behaviors in silicon materials, which have become more directly accessible over the past 20 years. Such progress has been made possible by newly developed experimental methods, first principle theories, and computer simulation techniques. The book is aimed at young researchers, scientists, and technicians in related industries. The main purposes are to provide readers with 1) the basic physics behind defects in silicon materials, 2) the atomistic modeling as well as the characterization techniques related to defects and impurities in silicon materials, and 3) an overview of the wide range of the research fields involved.

  12. Impurity engineering for germanium-doped Czochralski silicon wafer used for ultra large scale integrated circuit

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jiahe; Yang, Deren [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou (China)

    2009-07-01

    Internal gettering (IG) technology has been challenged by both the reduction of thermal budget during device fabrication and the enlargement of wafer diameter. Improving the properties of Czochralski (Cz) silicon wafers by intentional impurity doping, the so-called 'impurity engineering (IE)', is defined. Germanium has been found to be one of the important impurities for improving the internal gettering effect in Cz silicon wafer. In this paper, the investigations on IE involved with the conventional furnace anneal based denudation processing for germanium-doped Cz silicon wafer are reviewed. Meanwhile, the potential mechanisms of germanium effects for the IE of Cz silicon wafer are also interpreted based on the experimental facts. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Analytical and Experimental Evaluation of Joining Silicon Carbide to Silicon Carbide and Silicon Nitride to Silicon Nitride for Advanced Heat Engine Applications Phase II

    Energy Technology Data Exchange (ETDEWEB)

    Sundberg, G.J.

    1994-01-01

    Techniques were developed to produce reliable silicon nitride to silicon nitride (NCX-5101) curved joins which were used to manufacture spin test specimens as a proof of concept to simulate parts such as a simple rotor. Specimens were machined from the curved joins to measure the following properties of the join interlayer: tensile strength, shear strength, 22 C flexure strength and 1370 C flexure strength. In parallel, extensive silicon nitride tensile creep evaluation of planar butt joins provided a sufficient data base to develop models with accurate predictive capability for different geometries. Analytical models applied satisfactorily to the silicon nitride joins were Norton's Law for creep strain, a modified Norton's Law internal variable model and the Monkman-Grant relationship for failure modeling. The Theta Projection method was less successful. Attempts were also made to develop planar butt joins of siliconized silicon carbide (NT230).

  14. Silicon carbide whisker composites. (Latest citations from Engineered Materials abstracts). NewSearch

    Energy Technology Data Exchange (ETDEWEB)

    1994-11-01

    The bibliography contains citations concerning the manufacture and applications of silicon carbide whisker reinforced composites. Citations discuss the preparation of whiskers and the processing of composites containing the whiskers. Applications include aerospace engines, automotive components, engine components, and surgical implants. Physical properties such as bending strength, crack propagation, creep, fracture toughness, and stress strain curves are covered. Ceramic matrix, metal matrix, and carbon-carbon composites are examined. (Contains a minimum of 248 citations and includes a subject term index and title list.)

  15. Engineering near-infrared single-photon emitters with optically active spins in ultrapure silicon carbide

    Science.gov (United States)

    Fuchs, F.; Stender, B.; Trupke, M.; Simin, D.; Pflaum, J.; Dyakonov, V.; Astakhov, G. V.

    2015-07-01

    Vacancy-related centres in silicon carbide are attracting growing attention because of their appealing optical and spin properties. These atomic-scale defects can be created using electron or neutron irradiation; however, their precise engineering has not been demonstrated yet. Here, silicon vacancies are generated in a nuclear reactor and their density is controlled over eight orders of magnitude within an accuracy down to a single vacancy level. An isolated silicon vacancy serves as a near-infrared photostable single-photon emitter, operating even at room temperature. The vacancy spins can be manipulated using an optically detected magnetic resonance technique, and we determine the transition rates and absorption cross-section, describing the intensity-dependent photophysics of these emitters. The on-demand engineering of optically active spins in technologically friendly materials is a crucial step toward implementation of both maser amplifiers, requiring high-density spin ensembles, and qubits based on single spins.

  16. Complexes of silicon, vacancy, and hydrogen in diamond: A density functional study

    Science.gov (United States)

    Thiering, Gergő; Gali, Adam

    2015-10-01

    Paramagnetic luminescent point defects in diamond are increasingly important candidates for quantum information processing applications. Recently, the coherent manipulation of single silicon-vacancy defect spins has been demonstrated in chemical vapor deposited diamond samples where silicon may be introduced as a contamination in the growth process. Hydrogen impurity may simultaneously enter diamond too and form complexes with silicon-vacancy defects. However, relatively little is known about these complexes in diamond. Here we report plane-wave supercell density functional theory results on various complexes of silicon vacancy and hydrogen in diamond. We found a family of complexes of silicon, vacancies, and hydrogen atoms that are thermally stable in diamond with relatively low formation energies that might form yet unobserved or unidentified silicon-related defects. These complexes often show infrared optical transitions and are paramagnetic. We tentatively assign one of these complexes to a recently reported but yet unidentified infrared absorber center. We show that this center has a metastable triplet state and might exhibit a spin-selective decay to the ground state, thus it is an interesting candidate for quantum information processing applications. We also discuss here methodology aspects of calculating hyperfine parameters and intradefect level excitations in systems with notoriously complex electron states within hybrid density functional approach. We also demonstrate that a simplified approach using ab initio data can be very powerful to predict the relative intensities of the phonon replica associated with quasilocal vibration modes in the photoexcitation spectrum.

  17. Fostering Creative Engineers: A Key to Face the Complexity of Engineering Practice

    Science.gov (United States)

    Zhou, Chunfang

    2012-01-01

    Recent studies have argued a shift of thinking about engineering practice from a linear conception to a system understanding. The complexity of engineering practice has been thought of as the root of challenges for engineers. Moreover, creativity has been emphasised as one key capability that engineering students should master. This paper aims to…

  18. Fostering Creative Engineers: A Key to Face the Complexity of Engineering Practice

    Science.gov (United States)

    Zhou, Chunfang

    2012-01-01

    Recent studies have argued a shift of thinking about engineering practice from a linear conception to a system understanding. The complexity of engineering practice has been thought of as the root of challenges for engineers. Moreover, creativity has been emphasised as one key capability that engineering students should master. This paper aims to…

  19. Engineering of complex protein sialylation in plants

    Science.gov (United States)

    Kallolimath, Somanath; Castilho, Alexandra; Strasser, Richard; Grünwald-Gruber, Clemens; Altmann, Friedrich; Strubl, Sebastian; Galuska, Christina Elisabeth; Zlatina, Kristina; Galuska, Sebastian Peter; Werner, Stefan; Thiesler, Hauke; Werneburg, Sebastian; Hildebrandt, Herbert; Gerardy-Schahn, Rita; Steinkellner, Herta

    2016-01-01

    Sialic acids (Sias) are abundant terminal modifications of protein-linked glycans. A unique feature of Sia, compared with other monosaccharides, is the formation of linear homo-polymers, with its most complex form polysialic acid (polySia). Sia and polySia mediate diverse biological functions and have great potential for therapeutic use. However, technological hurdles in producing defined protein sialylation due to the enormous structural diversity render their precise investigation a challenge. Here, we describe a plant-based expression platform that enables the controlled in vivo synthesis of sialylated structures with different interlinkages and degree of polymerization (DP). The approach relies on a combination of stably transformed plants with transient expression modules. By the introduction of multigene vectors carrying the human sialylation pathway into glycosylation-destructed mutants, transgenic plants that sialylate glycoproteins in α2,6- or α2,3-linkage were generated. Moreover, by the transient coexpression of human α2,8-polysialyltransferases, polySia structures with a DP >40 were synthesized in these plants. Importantly, plant-derived polySia are functionally active, as demonstrated by a cell-based cytotoxicity assay and inhibition of microglia activation. This pathway engineering approach enables experimental investigations of defined sialylation and facilitates a rational design of glycan structures with optimized biotechnological functions. PMID:27444013

  20. Interfacial Engineering of Silicon Carbide Nanowire/Cellulose Microcrystal Paper toward High Thermal Conductivity.

    Science.gov (United States)

    Yao, Yimin; Zeng, Xiaoliang; Pan, Guiran; Sun, Jiajia; Hu, Jiantao; Huang, Yun; Sun, Rong; Xu, Jian-Bin; Wong, Ching-Ping

    2016-11-16

    Polymer composites with high thermal conductivity have attracted much attention, along with the rapid development of electronic devices toward higher speed and better performance. However, high interfacial thermal resistance between fillers and matrix or between fillers and fillers has been one of the primary bottlenecks for the effective thermal conduction in polymer composites. Herein, we report on engineering interfacial structure of silicon carbide nanowire/cellulose microcrystal paper by generating silver nanostructures. We show that silver nanoparticle-deposited silicon carbide nanowires as fillers can effectively enhance the thermal conductivity of the matrix. The in-plane thermal conductivity of the resultant composite paper reaches as high as 34.0 W/m K, which is one order magnitude higher than that of conventional polymer composites. Fitting the measured thermal conductivity with theoretical models qualitatively demonstrates that silver nanoparticles bring the lower interfacial thermal resistances both at silicon carbide nanowire/cellulose microcrystal and silicon carbide nanowire/silicon carbide nanowire interfaces. This interfacial engineering approach provides a powerful tool for sophisticated fabrication of high-performance thermal-management materials.

  1. Evaluation and silicon nitride internal combustion engine components. Final report, Phase I

    Energy Technology Data Exchange (ETDEWEB)

    Voldrich, W. [Allied-Signal Aerospace Co., Torrance, CA (United States). Garrett Ceramic Components Div.

    1992-04-01

    The feasibility of silicon nitride (Si{sub 3}N{sub 4}) use in internal combustion engines was studied by testing three different components for wear resistance and lower reciprocating mass. The information obtained from these preliminary spin rig and engine tests indicates several design changes are necessary to survive high-stress engine applications. The three silicon nitride components tested were valve spring retainers, tappet rollers, and fuel pump push rod ends. Garrett Ceramic Components` gas-pressure sinterable Si{sub 3}N{sub 4} (GS-44) was used to fabricate the above components. Components were final machined from densified blanks that had been green formed by isostatic pressing of GS-44 granules. Spin rig testing of the valve spring retainers indicated that these Si{sub 3}N{sub 4} components could survive at high RPM levels (9,500) when teamed with silicon nitride valves and lower spring tension than standard titanium components. Silicon nitride tappet rollers showed no wear on roller O.D. or I.D. surfaces, steel axles and lifters; however, due to the uncrowned design of these particular rollers the cam lobes indicated wear after spin rig testing. Fuel pump push rod ends were successful at reducing wear on the cam lobe and rod end when tested on spin rigs and in real-world race applications.

  2. Physical dispersion state and fluorescent property of Eu-complex in the Eu-complex/silicon rubber composites

    Institute of Scientific and Technical Information of China (English)

    WEN Shipeng; HU Shui; ZHANG Xiaoping; ZHANG Liqun; LIU Li

    2008-01-01

    The fluorescent complex Eu(TTA)2(Phen)(MA) (HTTA=2-Thenoyltdfluoroacetone, Phen=l,10-phenanthroline, MA=Maleic an-hydrider) was synthesized and characterized with elemental analysis, infrared spectrum (IR), scanning electron microscope (SEM), X-ray Diffraction(XRD), differential scanning calorimetry(DSC), and fluorescent measurement. To explore the effect of different physical disper-sion state of Eu-complex on the fluorescent property of the Eu-complex/silicon rubber composites, various quantities of Eu(TTA)2(phen) (MA) were mixed with silicon rubber (SIR) and peroxide to form uncured composites. These composites were vulcanized to obtain cured Eu-complex/SiR composites at 250 ℃, which was higher than the melting-point of Eu-complex. The SEM, XRD, DSC, and the fluorescent measurement of these composites showed that both the complex molecules dispersed in the silicon rubber during the melting process and the parent Eu-complex particles had positive effects on fluorescent property, whereas the re-crystallized Eu-complex particles and the ggregating complexes formed during the melting-process had negative effects on fluorescent property. For the uncured composites, their fluorescent intensities almost did not change with the increasing amount of Eu-complex. Furthermore, for the composites with small content of Eu-complex, their fluorescent intensities decreased significantly after curing, and this difference in fluorescent intensity became smaller as the content of Eu-complex increases.

  3. Interface Engineering of High Efficiency Organic-Silicon Heterojunction Solar Cells.

    Science.gov (United States)

    Yang, Lixia; Liu, Yaoping; Chen, Wei; Wang, Yan; Liang, Huili; Mei, Zengxia; Kuznetsov, Andrej; Du, Xiaolong

    2016-01-13

    Insufficient interface conformity is a challenge faced in hybrid organic-silicon heterojunction solar cells because of using conventional pyramid antireflection texturing provoking the porosity of interface. In this study, we tested alternative textures, in particular rounded pyramids and inverted pyramids to compare the performance. It was remarkably improved delivering 7.61%, 8.91% and 10.04% efficiency employing conventional, rounded, and inverted pyramids, respectively. The result was interpreted in terms of gradually improving conformity of the Ag/organic/silicon interface, together with the gradually decreasing serial resistance. Altogether, the present data may guide further efforts arising the interface engineering for mastering high efficient heterojunction solar cells.

  4. Optical pulse engineering and processing using optical nonlinearities of nanostructured waveguides made of silicon

    Science.gov (United States)

    Lavdas, Spyros; You, Jie; Osgood, Richard M.; Panoiu, Nicolae C.

    2015-08-01

    We present recent results pertaining to pulse reshaping and optical signal processing using optical nonlinearities of silicon-based tapered photonic wires and photonic crystal waveguides. In particular, we show how nonlinearity and dispersion engineering of tapered photonic wires can be employed to generate optical similaritons and achieve more than 10× pulse compression. We also discuss the properties of four-wave mixing pulse amplification and frequency conversion efficiency in long-period Bragg waveguides and photonic crystal waveguides. Finally, the influence of linear and nonlinear optical effects on the transmission bit-error rate in uniform photonic wires and photonic crystal waveguides made of silicon is discussed.

  5. Polarization insensitive wavelength conversion in a dispersion-engineered silicon waveguide

    DEFF Research Database (Denmark)

    Pu, Minhao; Hu, Hao; Peucheret, Christophe

    2012-01-01

    conversion performances for both the TE and TM modes. Bit-error rate measurements are performed and error-free operation is achieved. We also demonstrate polarization-insensitive wavelength conversion with a large separation between the idler and signal using a dual-pump configuration.......We experimentally demonstrate polarization-insensitive all optical wavelength conversion of a 10-Gb/s DPSK data signal based on four-wave mixing in a silicon waveguide with an angled-pump scheme. Dispersion engineering is applied to the silicon waveguide to obtain similar four-wave mixing...

  6. Engineering sidewall angles of silica-on-silicon waveguides

    DEFF Research Database (Denmark)

    Haiyan, Ou

    2004-01-01

    Burned photoresist is used as etch mask when producing silica-onsilicon waveguides. The sidewall angle of the optical glass waveguides is engineered by varying photoresist thickness and etch selectivity. The principle for the formation of the angles is introduced and very promising experimental...

  7. Complex Adaptive Systems of Systems (CASOS) engineering environment.

    Energy Technology Data Exchange (ETDEWEB)

    Detry, Richard Joseph; Linebarger, John Michael; Finley, Patrick D.; Maffitt, S. Louise; Glass, Robert John, Jr.; Beyeler, Walter Eugene; Ames, Arlo Leroy

    2012-02-01

    Complex Adaptive Systems of Systems, or CASoS, are vastly complex physical-socio-technical systems which we must understand to design a secure future for the nation. The Phoenix initiative implements CASoS Engineering principles combining the bottom up Complex Systems and Complex Adaptive Systems view with the top down Systems Engineering and System-of-Systems view. CASoS Engineering theory and practice must be conducted together to develop a discipline that is grounded in reality, extends our understanding of how CASoS behave and allows us to better control the outcomes. The pull of applications (real world problems) is critical to this effort, as is the articulation of a CASoS Engineering Framework that grounds an engineering approach in the theory of complex adaptive systems of systems. Successful application of the CASoS Engineering Framework requires modeling, simulation and analysis (MS and A) capabilities and the cultivation of a CASoS Engineering Community of Practice through knowledge sharing and facilitation. The CASoS Engineering Environment, itself a complex adaptive system of systems, constitutes the two platforms that provide these capabilities.

  8. Dispersion engineered high-Q silicon Nitride Ring-Resonators via Atomic Layer Deposition

    CERN Document Server

    Riemensberger, Johann; Herr, Tobias; Brasch, Victor; Holzwarth, Ronald; Kippenberg, Tobias J

    2012-01-01

    We demonstrate dispersion engineering of integrated silicon nitride based ring resonators through conformal coating with hafnium dioxide deposited on top of the structures via atomic layer deposition (ALD). Both, magnitude and bandwidth of anomalous dispersion can be significantly increased. All results are confirmed by high resolution frequency-comb-assisted-diode-laser spectroscopy and are in very good agreement with the simulated modification of the mode spectrum.

  9. Silicon carbide whisker composites. (Latest citations from Engineered Materials abstracts). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-01

    The bibliography contains citations concerning the manufacture and applications of silicon carbide whisker reinforced composites. Citations discuss the preparation of whiskers and the processing of composites containing the whiskers. Applications include aerospace engines, automotive components, engine components, and surgical implants. Physical properties such as bending strength, crack propagation, creep, fracture toughness, and stress strain curves are covered. Ceramic matrix, metal matrix, and carbon-carbon composites are examined. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  10. Managing and engineering in complex situations

    CERN Document Server

    Sousa-Poza, Andres

    2013-01-01

    With so many terms available to define the same thing, it would seem nearly irresponsible to introduce yet another term (complex situation) to describe a phenomenological state of such as a system. However, a complex situation infers both a broader meaning and imposes a different perspective. Complex in this context is dependent on understanding and reality rather than observer and knowledge.   Situation imposes a gestalt that cannot be characterized within a singular perspective that relegates paradox to a superior/subordinate hierarchy. This also infers that complex situation has no monotonic definition or each definition is by default incomplete. Therefore the perennial derivations for systems such as complex systems, system of systems, federation of systems is no longer a sufficient descriptor for complex situation.  Ergo system and its genealogy lack the constitution to define complex situations. The books' intent is to explore this pathology through a series of papers written by authors that work in ...

  11. Investigation of silicon complexes in Si-doped calcium phosphate bioceramics

    Science.gov (United States)

    Gillespie, P.; Stott, M. J.; Sayer, M.; Wu, G.

    2007-03-01

    Silicon doped calcium phosphate materials have drawn great interest as bioceramics for bone repair due to their enhanced bioactivity. However, the low level of doping in these materials, generally ˜1 wt.%, makes it difficult to determine the effects the silicon has on the structure of these materials. In this study, silicon substituted hydroxyapatite (Si-HA), silicon stabilized alpha tricalcium phosphate (Si-TCP), and a multi-phase mixture consisting of approximately 75% Si-TCP with the remainder being mainly Si-HA have been synthesized using isotopically enriched silica containing ^29Si. ^29Si magic-angle spinning nuclear magnetic resonance spectroscopy (MAS-NMR) has been used to examine the silicon complexes within these materials resulting from the substitution of SiO4^4- for PO4^3- and the required charge compensation mechanism needed to achieve this. Previous ab initio studies on these materials have investigated charge compensation mechanisms to suggest possible silicon complexes and these serve as a basis for interpreting the NMR results.

  12. Applied complex variables for scientists and engineers

    CERN Document Server

    Kwok, Yue Kuen

    2010-01-01

    This introduction to complex variable methods begins by carefully defining complex numbers and analytic functions, and proceeds to give accounts of complex integration, Taylor series, singularities, residues and mappings. Both algebraic and geometric tools are employed to provide the greatest understanding, with many diagrams illustrating the concepts introduced. The emphasis is laid on understanding the use of methods, rather than on rigorous proofs. Throughout the text, many of the important theoretical results in complex function theory are followed by relevant and vivid examples in physical sciences. This second edition now contains 350 stimulating exercises of high quality, with solutions given to many of them. Material has been updated and additional proofs on some of the important theorems in complex function theory are now included, e.g. the Weierstrass–Casorati theorem. The book is highly suitable for students wishing to learn the elements of complex analysis in an applied context.

  13. NITRD LSN Workshop Report on Complex Engineered Networks

    Data.gov (United States)

    Networking and Information Technology Research and Development, Executive Office of the President — Complex engineered networks are everywhere: power grids, Internet, transportation networks, and more. They are being used more than ever before, and yet our...

  14. Bi-project management in engineering complex industrial construction projects

    NARCIS (Netherlands)

    Velde, Robert R. van der; Donk, Dirk Pieter van

    2000-01-01

    Engineering large industrial construction projects is usually a complex task with several co-operating actors. This paper investigates such projects, characterised by two main actors: the owner of the installation (the client organisation) responsible for the engineering of the production process,

  15. Structural and Topology Optimization of Complex Civil Engineering Structures

    DEFF Research Database (Denmark)

    Hald, Frederik; Kirkegaard, Poul Henning; Andersen, Lars Vabbersgaard

    2013-01-01

    This paper shows the use of topology optimization for finding an optimized form for civil engineering structures. Today topology optimization and shape optimization have been integrated in several commercial finite element codes. Here, the topology of two complex civil engineering structures...

  16. Gold and Platinum in Silicon - Isolated Impurities Complexes

    CERN Multimedia

    Mcglynn, P

    2002-01-01

    %IS357 :\\\\ \\\\ Gold and platinum impurities in silicon are exploited for the control of minority carrier lifetimes, and this important feature has resulted in sustained research interest over several decades. Although the properties of isolated substitutional Au~atoms are well understood, this is not the case for Pt. Considerable uncertainty exists regarding the nature of several Pt related defects observed in Electron Paramagnetic Resonance~(EPR) and Photo~Luminescence~(PL). One of the objectives of this experiment is to exploit the transformation of radioactive Au isotopes as a means of producing specific Pt centres, and to use our thorough knowledge of Au in silicon to guide in the interpretation of data obtained for the centres when they transform to Pt.\\\\ \\\\ In addition to isolated impurities, the experiment also addresses the question of pairs of atoms formed by Au and Pt. Studies of these impurity pairs have been reported, but the benefits of a direct comparison of the defects in both the Au and Pt form...

  17. Silicon subsystem mechanical engineering closeout report for the Solenoidal Detector Collaboration

    Energy Technology Data Exchange (ETDEWEB)

    Hanlon, J.; Christensen, R.W.; Hayman, G.; Jones, D.C.; Ross, R.; Wilds, W.; Yeamans, S.; Ziock, H.J.

    1995-02-01

    The authors group at Los Alamos National Laboratory was responsible for the mechanical engineering of the silicon tracking system of the Solenoidal Detector Collaboration (SDC) experiment of the Superconducting Super Collider (SSC) project. The responsibility included the overall design of the system from the mechanical point of view, development and integration of the cooling system, which was required to remove the heat generated by the front-end electronics, assembly of the system to extremely tight tolerances, and verification that the construction and operational stability and alignment tolerances would be met. A detailed description of the concepts they developed and the work they performed can be found in a report titled ``Silicon Subsystem Mechanical Engineering Work for the Solenoidal Detector Collaboration`` which they submitted to the SSC Laboratory. In addition to the mechanical engineering work, they also performed activation, background, and shielding studies for the SSC program. Much of the work they performed was potentially useful for other future high energy physics (HEP) projects. This report describes the closeout work that was performed for the Los Alamos SDC project. Four major tasks were identified for completion: (1) integration of the semi-automated assembly station being developed and construction of a precision part to demonstrate solutions to important general assembly problems (the station was designed to build precision silicon tracker subassemblies); (2) build a state-of-the-art TV holography (TVH) system to use for detector assembly stability tests; (3) design, build, and test a water based cooling system for a full silicon shell prototype; and (4) complete and document the activation, background, and shielding studies, which is covered in a separate report.

  18. Distilling complexity to advance cardiac tissue engineering

    OpenAIRE

    Ogle, Brenda M.; Bursac, Nenad; Domian, Ibrahim; Huang, Ngan F.; Menasché, Philippe; Murry, Charles; Pruitt, Beth; Radisic, Milica; Wu, Joseph C; Wu, Sean M.; Zhang, Jianyi; Zimmermann, Wolfram-Hubertus; Vunjak-Novakovic, Gordana

    2016-01-01

    The promise of cardiac tissue engineering is in the ability to recapitulate in vitro the functional aspects of healthy heart and disease pathology as well as to design replacement muscle for clinical therapy. Parts of this promise have been realized; others have not. In a meeting of scientists in this field, five central challenges or “big questions” were articulated that, if addressed, could substantially advance the current state-of-the-art in modeling heart disease and realizing heart repa...

  19. Assembly, characterization, and electrochemical properties of immobilized metal bipyridyl complexes on silicon(111) surfaces.

    Science.gov (United States)

    Lattimer, Judith R C; Blakemore, James D; Sattler, Wesley; Gul, Sheraz; Chatterjee, Ruchira; Yachandra, Vittal K; Yano, Junko; Brunschwig, Bruce S; Lewis, Nathan S; Gray, Harry B

    2014-10-28

    Silicon(111) surfaces have been functionalized with mixed monolayers consisting of submonolayer coverages of immobilized 4-vinyl-2,2'-bipyridyl (1, vbpy) moieties, with the remaining atop sites of the silicon surface passivated by methyl groups. As the immobilized bipyridyl ligands bind transition metal ions, metal complexes can be assembled on the silicon surface. X-ray photoelectron spectroscopy (XPS) demonstrates that bipyridyl complexes of [Cp*Rh], [Cp*Ir], and [Ru(acac)2] were formed on the surface (Cp* is pentamethylcyclopentadienyl, acac is acetylacetonate). For the surface prepared with Ir, X-ray absorption spectroscopy at the Ir LIII edge showed an edge energy as well as post-edge features that were essentially identical with those observed on a powder sample of [Cp*Ir(bpy)Cl]Cl (bpy is 2,2'-bipyridyl). Charge-carrier lifetime measurements confirmed that the silicon surfaces retain their highly favorable photoelectronic properties upon assembly of the metal complexes. Electrochemical data for surfaces prepared on highly doped, n-type Si(111) electrodes showed that the assembled molecular complexes were redox active. However the stability of the molecular complexes on the surfaces was limited to several cycles of voltammetry.

  20. Managing complexity challenges for industrial engineering and operations management

    CERN Document Server

    López-Paredes, Adolfo; Pérez-Ríos, José

    2014-01-01

    This book presents papers by experts in the field of Industrial Engineering, covering topics in business strategy; modelling and simulation in operations research; logistics and production; service systems; innovation and knowledge; and project management. The focus of operations and production management has evolved from product and manufacturing to the capabilities of firms and collaborative management. Nowadays, Industrial Engineering is concerned with the study of how to design, modify, control and improve the performance of complex systems. It has extended its scope to any physical landscape populated by social agents. This raises a major challenge to Industrial Engineering:  managing complexity. This volume shows how experts are dealing with this challenge.

  1. The study of the influence of uniaxial stress on impurity complexes in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Tessema, G. [Helmholtz-Institut fuer Strahlen-und Kernphysik, Nussallee 14-16, 53115 Bonn (Germany)]. E-mail: genene@gmx.net; Vianden, R. [Helmholtz-Institut fuer Strahlen-und Kernphysik, Nussallee 14-16, 53115 Bonn (Germany)

    2005-02-15

    The influence of external uniaxial stress on the different indium-donor complexes in silicon has been studied using the perturbed {gamma} -{gamma} angular correlation (PAC) method. Such effect of an applied stress is detected by means of the probe atoms situated at different complexes in the sample. The current results showed that the responses of the probes in an extrinsic silicon samples are found to be dissimilar for the same value of stress. Such change in the local environments of the probe atoms could be associated with the various strain field created by the implantations of varied size of impurities. The phosphorous implantation in silicon has even lead to the complete absence of observable effect of the applied stress suggesting significant lose of the elasticity of the sample.

  2. Shallow dopants in nanostructered and in isotopically engineered silicon

    Energy Technology Data Exchange (ETDEWEB)

    Stegner, Andre Rainer

    2011-01-15

    isotopically engineered {sup 28}Si samples, we have found that the broad inter-subband EPR line of B acceptors shows an inhomogeneous Lorentzian broadening proportional to the concentration of carbon, oxygen and boron point defects down to approximately 5 x 10{sup 15} cm{sup -3} caused by local strain fields. For samples with less than 5 x 10{sup 15} cm{sup -3} point defects, we have found a linewidth threshold of {approx}2.2 mT for which we have discussed different possible explanations. (orig.)

  3. How Engineers Negotiate Domain Boundaries in a Complex, Interdisciplinary Engineering Project

    Science.gov (United States)

    Panther, Grace; Montfort, Devlin; Pirtle, Zachary

    2017-01-01

    Engineering educators have an essential role in preparing engineers to work in a complex, interdisciplinary workforce. While much engineering education focuses on teaching students to develop disciplinary expertise in specific engineering domains, there is a strong need to teach engineers about the knowledge that they develop or use in their work (Bucciarelli 1994, Allenby Sarewitz, 2011; Frodeman, 2013). The purpose of this research is to gain a better understanding of the knowledge systems of practicing engineers through observations of their practices such that the insights learned can guide future education efforts. Using an example from a complex and interdisciplinary engineering project, this paper presents a case study overviewing the types of epistemological (or knowledge-acquiring or using) complexities that engineers navigate. Specifically, we looked at a discussion of the thermal design of a CubeSat that occurred during an engineering review at NASA. We analyzed the review using a framework that we call 'peak events', or pointed discussions between reviewers, project engineers, and managers. We examined the dialog within peak events to identify the ways that knowledge was brought to bear, highlighting discussions of uncertainty and the boundaries of knowledge claims. We focus on one example discussion surrounding the thermal design of the CubeSat, which provides a particularly thorough example of a knowledge system since the engineers present explained, justified, negotiated, and defended knowledge within a social setting. Engineering students do not get much practice or instruction in explicitly negotiating knowledge systems and epistemic standards in this way. We highlight issues that should matter to engineering educators, such as the need to discuss what level of uncertainty is sufficient and the need to negotiate boundaries of system responsibility. Although this analysis is limited to a single discussion or 'peak event', our case shows that this

  4. Complex variables for scientists and engineers

    CERN Document Server

    Paliouras, John D

    2014-01-01

    This outstanding text for undergraduate students of science and engineering requires only a standard course in elementary calculus. Designed to provide a thorough understanding of fundamental concepts and create the basis for higher-level courses, the treatment features numerous examples and extensive exercise sections of varying difficulty, plus answers to selected exercises.The two-part approach begins with the development of the primary concept of analytic function, advancing to the Cauchy integral theory, the series development of analytic functions through evaluation of integrals by resid

  5. Rudiments of complexity theory for scientists and engineers

    OpenAIRE

    Vinay, V.

    1994-01-01

    Complexity theory is an important and growing area in computer science that has caught the imagination of many researchers in mathematics, physics and biology. In order to reach out to a large section of scientists and engineers, the paper introduces elementary concepts in complexity theory in a informal manner, motivating the reader with many examples.

  6. Point defect engineering strategies to suppress A-center formation in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Chroneos, A. [Department of Materials, Imperial College London, London SW7 2AZ (United Kingdom); Londos, C. A.; Sgourou, E. N. [Solid State Physics Section, University of Athens, Panepistimiopolis Zografos, Athens 157 84 (Greece); Pochet, P. [Laboratoire de Simulation Atomistique (L-Sim), SP2M, INAC, CEA-UJF, 38054 Grenoble Cedex 9 (France)

    2011-12-12

    We investigate the impact of tin doping on the formation of vacancy-oxygen pairs (VO or A-centers) and their conversion to VO{sub 2} clusters in electron-irradiated silicon. The experimental results are consistent with previous reports that Sn doping suppresses the formation of the A-center. We introduce a model to account for the observed differences under both Sn-poor and Sn-rich doping conditions. Using density functional theory calculations, we propose point defect engineering strategies to reduce the concentration of the deleterious A-centers in silicon. We predict that doping with lead, zirconium, or hafnium will lead to the suppression of the A-centers.

  7. Experimental broadband absorption enhancement in silicon nanohole structures with optimized complex unit cells.

    Science.gov (United States)

    Lin, Chenxi; Martínez, Luis Javier; Povinelli, Michelle L

    2013-09-09

    We design silicon membranes with nanohole structures with optimized complex unit cells that maximize broadband absorption. We fabricate the optimized design and measure the optical absorption. We demonstrate an experimental broadband absorption about 3.5 times higher than an equally-thick thin film.

  8. Research on the Fault Coefficient in Complex Electrical Engineering

    Directory of Open Access Journals (Sweden)

    Yi Sun

    2015-08-01

    Full Text Available Fault detection and isolation in a complex system are research hotspots and frontier problems in the reliability engineering field. Fault identification can be regarded as a procedure of excavating key characteristics from massive failure data, then classifying and identifying fault samples. In this paper, based on the fundamental of feature extraction about the fault coefficient, we will discuss the fault coefficient feature in complex electrical engineering in detail. For general fault types in a complex power system, even if there is a strong white Gaussian stochastic interference, the fault coefficient feature is still accurate and reliable. The results about comparative analysis of noise influence will also demonstrate the strong anti-interference ability and great redundancy of the fault coefficient feature in complex electrical engineering.

  9. The art of insight in science and engineering mastering complexity

    CERN Document Server

    Mahajan, Sanjoy

    2014-01-01

    In this book, Sanjoy Mahajan shows us that the way to master complexity is through insight rather than precision. Precision can overwhelm us with information, whereas insight connects seemingly disparate pieces of information into a simple picture. Unlike computers, humans depend on insight. Based on the author's fifteen years of teaching at MIT, Cambridge University, and Olin College, The Art of Insight in Science and Engineering shows us how to build insight and find understanding, giving readers tools to help them solve any problem in science and engineering. To master complexity, we can organize it or discard it. The Art of Insight in Science and Engineering first teaches the tools for organizing complexity, then distinguishes the two paths for discarding complexity: with and without loss of information. Questions and problems throughout the text help readers master and apply these groups of tools. Armed with this three-part toolchest, and without complicated mathematics, readers can estimate the flight ...

  10. Complex Engineered Systems: A New Paradigm

    Science.gov (United States)

    Mina, Ali A.; Braha, Dan; Bar-Yam, Yaneer

    Human history is often seen as an inexorable march towards greater complexity — in ideas, artifacts, social, political and economic systems, technology, and in the structure of life itself. While we do not have detailed knowledge of ancient times, it is reasonable to conclude that the average resident of New York City today faces a world of much greater complexity than the average denizen of Carthage or Tikal. A careful consideration of this change, however, suggests that most of it has occurred recently, and has been driven primarily by the emergence of technology as a force in human life. In the 4000 years separating the Indus Valley Civilization from 18th century Europe, human transportation evolved from the bullock cart to the hansom, and the methods of communication used by George Washington did not differ significantly from those used by Alexander or Rameses. The world has moved radically towards greater complexity in the last two centuries. We have moved from buggies and letter couriers to airplanes and the Internet — an increase in capacity, and through its diversity also in complexity, orders of magnitude greater than that accumulated through the rest of human history. In addition to creating iconic artifacts — the airplane, the car, the computer, the television, etc. — this change has had a profound effect on the scope of experience by creating massive, connected and multiultra- level systems — traffic networks, power grids, markets, multinational corporations — that defy analytical understanding and seem to have a life of their own. This is where complexity truly enters our lives.

  11. A Complexity measure based on Requirement Engineering Document

    CERN Document Server

    Sharma, Ashish

    2010-01-01

    Research shows, that the major issue in development of quality software is precise estimation. Further this estimation depends upon the degree of intricacy inherent in the software i.e. complexity. This paper attempts to empirically demonstrate the proposed complexity which is based on IEEE Requirement Engineering document. It is said that a high quality SRS is pre requisite for high quality software. Requirement Engineering document (SRS) is a specification for a particular software product, program or set of program that performs some certain functions for a specific environment. The various complexity measure given so far are based on Code and Cognitive metrics value of software, which are code based. So these metrics provide no leverage to the developer of the code. Considering the shortcoming of code based approaches, the proposed approach identifies complexity of software immediately after freezing the requirement in SDLC process. The proposed complexity measure compares well with established complexity...

  12. Fluorescence Properties of Eu3+/Gd3+/Citric Acid Mixed Complexes Doping in Silicon Rubber Matrix

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Series of doped rare earth complexes-EuxGd(1-x)(CA)3·nH2O (CA=citric acid) were synthesized. Some characterizations were taken for these complexes. The experimental results shows that the doped rare earth complexes have the best fluorescence property when the ratio of Eu and Gd is from 0.7 to 0.3. Silicon rubber-based composites were prepared by mechanical blending the EuxGd(1-x)(CA)3·nH2O and silicon rubber. Then, the fluorescent property of the composites was studied. It is found that the fluorescence intensity of the composites increase linearly with the contents of the rare earth complexes increasing.

  13. State analysis requirements database for engineering complex embedded systems

    Science.gov (United States)

    Bennett, Matthew B.; Rasmussen, Robert D.; Ingham, Michel D.

    2004-01-01

    It has become clear that spacecraft system complexity is reaching a threshold where customary methods of control are no longer affordable or sufficiently reliable. At the heart of this problem are the conventional approaches to systems and software engineering based on subsystem-level functional decomposition, which fail to scale in the tangled web of interactions typically encountered in complex spacecraft designs. Furthermore, there is a fundamental gap between the requirements on software specified by systems engineers and the implementation of these requirements by software engineers. Software engineers must perform the translation of requirements into software code, hoping to accurately capture the systems engineer's understanding of the system behavior, which is not always explicitly specified. This gap opens up the possibility for misinterpretation of the systems engineer's intent, potentially leading to software errors. This problem is addressed by a systems engineering tool called the State Analysis Database, which provides a tool for capturing system and software requirements in the form of explicit models. This paper describes how requirements for complex aerospace systems can be developed using the State Analysis Database.

  14. State analysis requirements database for engineering complex embedded systems

    Science.gov (United States)

    Bennett, Matthew B.; Rasmussen, Robert D.; Ingham, Michel D.

    2004-01-01

    It has become clear that spacecraft system complexity is reaching a threshold where customary methods of control are no longer affordable or sufficiently reliable. At the heart of this problem are the conventional approaches to systems and software engineering based on subsystem-level functional decomposition, which fail to scale in the tangled web of interactions typically encountered in complex spacecraft designs. Furthermore, there is a fundamental gap between the requirements on software specified by systems engineers and the implementation of these requirements by software engineers. Software engineers must perform the translation of requirements into software code, hoping to accurately capture the systems engineer's understanding of the system behavior, which is not always explicitly specified. This gap opens up the possibility for misinterpretation of the systems engineer's intent, potentially leading to software errors. This problem is addressed by a systems engineering tool called the State Analysis Database, which provides a tool for capturing system and software requirements in the form of explicit models. This paper describes how requirements for complex aerospace systems can be developed using the State Analysis Database.

  15. Thermally Assisted Tunneling of the B-H Complex in Silicon

    Science.gov (United States)

    Noya, José C.; Herrero, Carlos P.; Ramírez, Rafael

    1997-07-01

    Jump rate constants of atomic hydrogen and deuterium in boron-doped crystalline silicon are calculated using quantum transition-state theory, based on the path-integral centroid formalism. A break in the slope of the Arrhenius plot for the jump rate of hydrogen is obtained at T~60 K, indicating a crossover from thermally activated quasiclassical motion over a barrier to thermally assisted quantum tunneling, in good agreement with previous experimental results. For deuterium, no deviation from an Arrhenius law is found down to 30 K. It is shown that the defect complex undergoing quantum tunneling consists of hydrogen, boron, and the nearest silicon atoms.

  16. Engineering of silicon surfaces at the micro- and nanoscales for cell adhesion and migration control

    Directory of Open Access Journals (Sweden)

    Torres-Costa V

    2012-02-01

    Full Text Available Vicente Torres-Costa1, Gonzalo Martínez-Muñoz2, Vanessa Sánchez-Vaquero3, Álvaro Muñoz-Noval1, Laura González-Méndez3, Esther Punzón-Quijorna1,4, Darío Gallach-Pérez1, Miguel Manso-Silván1, Aurelio Climent-Font1,4, Josefa P García-Ruiz3, Raúl J Martín-Palma11Department of Applied Physics, 2Department of Computer Science, 3Department of Molecular Biology, 4Centre for Micro Analysis of Materials, Universidad Autónoma de Madrid, Madrid, SpainAbstract: The engineering of surface patterns is a powerful tool for analyzing cellular communication factors involved in the processes of adhesion, migration, and expansion, which can have a notable impact on therapeutic applications including tissue engineering. In this regard, the main objective of this research was to fabricate patterned and textured surfaces at micron- and nanoscale levels, respectively, with very different chemical and topographic characteristics to control cell–substrate interactions. For this task, one-dimensional (1-D and two-dimensional (2-D patterns combining silicon and nanostructured porous silicon were engineered by ion beam irradiation and subsequent electrochemical etch. The experimental results show that under the influence of chemical and morphological stimuli, human mesenchymal stem cells polarize and move directionally toward or away from the particular stimulus. Furthermore, a computational model was developed aiming at understanding cell behavior by reproducing the surface distribution and migration of human mesenchymal stem cells observed experimentally.Keywords: surface patterns, silicon, hMSCs, ion-beam patterning

  17. Bioinspired Concepts: Unified Theory for Complex Biological and Engineering Systems

    Science.gov (United States)

    2006-01-01

    long cycles , we achieve equality in (4) by essentially using the operating scheme of the Carnot heat engine. This is a physical hard limit: It is...control theory, and computational complexity (classically associated with names such as Carnot , Shannon, Bode, and Turing) all assume incompat- ible...substantially extended from an analytic tool of reverse -engineering TCP congestion control to a general approach to understand in- teractions across layers

  18. Tailoring Enterprise Systems Engineering Policy for Project Scale and Complexity

    Science.gov (United States)

    Cox, Renee I.; Thomas, L. Dale

    2014-01-01

    Space systems are characterized by varying degrees of scale and complexity. Accordingly, cost-effective implementation of systems engineering also varies depending on scale and complexity. Recognizing that systems engineering and integration happen everywhere and at all levels of a given system and that the life cycle is an integrated process necessary to mature a design, the National Aeronautic and Space Administration's (NASA's) Marshall Space Flight Center (MSFC) has developed a suite of customized implementation approaches based on project scale and complexity. While it may be argued that a top-level system engineering process is common to and indeed desirable across an enterprise for all space systems, implementation of that top-level process and the associated products developed as a result differ from system to system. The implementation approaches used for developing a scientific instrument necessarily differ from those used for a space station. .

  19. Electrically active light-element complexes in silicon crystals grown by cast method

    Science.gov (United States)

    Sato, Kuniyuki; Ogura, Atsushi; Ono, Haruhiko

    2016-09-01

    Electrically active light-element complexes called thermal donors and shallow thermal donors in silicon crystals grown by the cast method were studied by low-temperature far-infrared absorption spectroscopy. The relationship between these complexes and either crystal defects or light-element impurities was investigated by comparing different types of silicon crystals, that is, conventional cast-grown multicrystalline Si, seed-cast monolike-Si, and Czochralski-grown Si. The dependence of thermal and the shallow thermal donors on the light-element impurity concentration and their annealing behaviors were examined to compare the crystals. It was found that crystal defects such as dislocations and grain boundaries did not affect the formation of thermal or shallow thermal donors. The formation of these complexes was dominantly affected by the concentration of light-element impurities, O and C, independent of the existence of crystal defects.

  20. Four-wave mixing in slow light engineered silicon photonic crystal waveguides.

    Science.gov (United States)

    Monat, C; Ebnali-Heidari, M; Grillet, C; Corcoran, B; Eggleton, B J; White, T P; O'Faolain, L; Li, J; Krauss, T F

    2010-10-25

    We experimentally investigate four-wave mixing (FWM) in short (80 μm) dispersion-engineered slow light silicon photonic crystal waveguides. The pump, probe and idler signals all lie in a 14 nm wide low dispersion region with a near-constant group velocity of c/30. We measure an instantaneous conversion efficiency of up to -9dB between the idler and the continuous-wave probe, with 1W peak pump power and 6 nm pump-probe detuning. This conversion efficiency is found to be considerably higher (>10 × ) than that of a Si nanowire with a group velocity ten times larger. In addition, we estimate the FWM bandwidth to be at least that of the flat band slow light window. These results, supported by numerical simulations, emphasize the importance of engineering the dispersion of PhC waveguides to exploit the slow light enhancement of FWM efficiency, even for short device lengths.

  1. Visualization and simulation of complex flows in biomedical engineering

    CERN Document Server

    Imai, Yohsuke; Ishikawa, Takuji; Oliveira, Mónica

    2014-01-01

    This book focuses on the most recent advances in the application of visualization and simulation methods to understand the flow behavior of complex fluids used in biomedical engineering and other related fields. It shows the physiological flow behavior in large arteries, microcirculation, respiratory systems and in biomedical microdevices.

  2. Can Models Capture the Complexity of the Systems Engineering Process?

    Science.gov (United States)

    Boppana, Krishna; Chow, Sam; de Weck, Olivier L.; Lafon, Christian; Lekkakos, Spyridon D.; Lyneis, James; Rinaldi, Matthew; Wang, Zhiyong; Wheeler, Paul; Zborovskiy, Marat; Wojcik, Leonard A.

    Many large-scale, complex systems engineering (SE) programs have been problematic; a few examples are listed below (Bar-Yam, 2003 and Cullen, 2004), and many others have been late, well over budget, or have failed: Hilton/Marriott/American Airlines system for hotel reservations and flights; 1988-1992; 125 million; "scrapped"

  3. Computational error and complexity in science and engineering computational error and complexity

    CERN Document Server

    Lakshmikantham, Vangipuram; Chui, Charles K; Chui, Charles K

    2005-01-01

    The book "Computational Error and Complexity in Science and Engineering” pervades all the science and engineering disciplines where computation occurs. Scientific and engineering computation happens to be the interface between the mathematical model/problem and the real world application. One needs to obtain good quality numerical values for any real-world implementation. Just mathematical quantities symbols are of no use to engineers/technologists. Computational complexity of the numerical method to solve the mathematical model, also computed along with the solution, on the other hand, will tell us how much computation/computational effort has been spent to achieve that quality of result. Anyone who wants the specified physical problem to be solved has every right to know the quality of the solution as well as the resources spent for the solution. The computed error as well as the complexity provide the scientific convincing answer to these questions. Specifically some of the disciplines in which the book w...

  4. Aluminum-jointed silicon dioxide octagon nanohelix array with desired complex refractive index.

    Science.gov (United States)

    Jen, Yi-Jun; Chen, Chien-Chi; Jheng, Ci-Yao

    2014-06-15

    In this Letter, glancing angle deposition is used to form an aluminum-jointed silicon dioxide octagon nanohelix array as a 3D nanostructured thin film. As a sculptured metal-dielectric composite, the film exhibits a complex refractive index of near unity with a small imaginary part. This structured film is demonstrated as an efficient light absorber to absorb light in a broad band and over a wide range of angles for both polarization states.

  5. Design, analysis, and characterization of stress-engineered 3D microstructures comprised of PECVD silicon oxide and nitride

    Science.gov (United States)

    Pi, Chia-Hsing; Turner, Kevin T.

    2016-06-01

    Microelectromechanical systems (MEMS) are typically 2D or quasi-3D structures fabricated using surface and bulk micromachining processes. In this work, an approach for 3D structure fabrication based on stress engineering is demonstrated. Specifically, sub-mm 3D spherical cage-like structures are realized through the deformation of bilayers of residually-stressed silicon oxide and silicon nitride with micrometer-scale thicknesses. Analytical and finite models to predict the shape of stress-engineered structures based on geometry and residual stress are described and used for structure design. A systematic experimental study was performed to quantify residual stresses in silicon nitride films made by plasma-enhanced chemical vapor deposition (PECVD). The measurements show that the residual stress of PECVD silicon nitride can be tuned over a wide range of tensile stresses through the control of deposition parameters, such as flow rate and power. Stress engineered 3D cage-like structures comprised of PECVD silicon nitride and oxide films were fabricated. 3D structures with a range of curvatures were demonstrated. The measured geometry of the fabricated structures are in good agreement with predictions from analytical and finite element models.

  6. Data driven uncertainty evaluation for complex engineered system design

    Science.gov (United States)

    Liu, Boyuan; Huang, Shuangxi; Fan, Wenhui; Xiao, Tianyuan; Humann, James; Lai, Yuyang; Jin, Yan

    2016-09-01

    Complex engineered systems are often difficult to analyze and design due to the tangled interdependencies among their subsystems and components. Conventional design methods often need exact modeling or accurate structure decomposition, which limits their practical application. The rapid expansion of data makes utilizing data to guide and improve system design indispensable in practical engineering. In this paper, a data driven uncertainty evaluation approach is proposed to support the design of complex engineered systems. The core of the approach is a data-mining based uncertainty evaluation method that predicts the uncertainty level of a specific system design by means of analyzing association relations along different system attributes and synthesizing the information entropy of the covered attribute areas, and a quantitative measure of system uncertainty can be obtained accordingly. Monte Carlo simulation is introduced to get the uncertainty extrema, and the possible data distributions under different situations is discussed in detail. The uncertainty values can be normalized using the simulation results and the values can be used to evaluate different system designs. A prototype system is established, and two case studies have been carried out. The case of an inverted pendulum system validates the effectiveness of the proposed method, and the case of an oil sump design shows the practicability when two or more design plans need to be compared. This research can be used to evaluate the uncertainty of complex engineered systems completely relying on data, and is ideally suited for plan selection and performance analysis in system design.

  7. Data driven uncertainty evaluation for complex engineered system design

    Science.gov (United States)

    Liu, Boyuan; Huang, Shuangxi; Fan, Wenhui; Xiao, Tianyuan; Humann, James; Lai, Yuyang; Jin, Yan

    2016-05-01

    Complex engineered systems are often difficult to analyze and design due to the tangled interdependencies among their subsystems and components. Conventional design methods often need exact modeling or accurate structure decomposition, which limits their practical application. The rapid expansion of data makes utilizing data to guide and improve system design indispensable in practical engineering. In this paper, a data driven uncertainty evaluation approach is proposed to support the design of complex engineered systems. The core of the approach is a data-mining based uncertainty evaluation method that predicts the uncertainty level of a specific system design by means of analyzing association relations along different system attributes and synthesizing the information entropy of the covered attribute areas, and a quantitative measure of system uncertainty can be obtained accordingly. Monte Carlo simulation is introduced to get the uncertainty extrema, and the possible data distributions under different situations is discussed in detail. The uncertainty values can be normalized using the simulation results and the values can be used to evaluate different system designs. A prototype system is established, and two case studies have been carried out. The case of an inverted pendulum system validates the effectiveness of the proposed method, and the case of an oil sump design shows the practicability when two or more design plans need to be compared. This research can be used to evaluate the uncertainty of complex engineered systems completely relying on data, and is ideally suited for plan selection and performance analysis in system design.

  8. Research and assessment of competitiveness of large engineering complexes

    Directory of Open Access Journals (Sweden)

    Krivorotov V.V.

    2017-01-01

    Full Text Available The urgency of the problem of ensuring the competitiveness of manufacturing and high-tech sectors is shown. Substantiated the decisive role of the large industrial complexes in the formation of the results of the national economy; the author’s interpretation of the concept of “industrial complex” with regard to current economic systems. Current approaches to assessing the competitiveness of enterprises and industrial complexes are analyzed; showing their main advantages and disadvantages. Provides scientific-methodological approach to the study and management of competitiveness of a large industrial complex; the description of its main units is provided. As a Central element of the scientific methodology approach proposed the methodology for assessing the competitiveness of a large industrial complex based on the Pattern-method; a modular system of indicators of competitiveness is developed and its adaptation to a large engineering complexes is made. Using the developed methodology the competitiveness of one of the largest engineering complexes of the group of companies Uralelectrotyazhmash, which is the leading enterprises in electrotechnical industry of Russia is assessed. The evaluation identified the main problems and bottlenecks in the development of these enterprises, and their comparison with leading competitors is provided. According to the results of the study the main conclusions and recommendations are formed.

  9. Metallic-like bonding in plasma-born silicon nanocrystals for nanoscale bandgap engineering.

    Science.gov (United States)

    Vach, Holger; Ivanova, Lena V; Timerghazin, Qadir K; Jardali, Fatme; Le, Ha-Linh Thi

    2016-10-27

    Based on ab initio molecular dynamics simulations, we show that small nanoclusters of about 1 nm size spontaneously generated in a low-temperature silane plasma do not possess tetrahedral structures, but are ultrastable. Apparently small differences in the cluster structure result in substantial modifications in their electric, magnetic, and optical properties, without the need for any dopants. Their non-tetrahedral geometries notably lead to electron deficient bonds that introduce efficient electron delocalization that strongly resembles the one of a homogeneous electron gas leading to metallic-like bonding within a semiconductor nanocrystal. As a result, pure hydrogenated silicon clusters that form by self-assembly in a plasma reactor possess optical gaps covering most of the solar spectrum from 1.0 eV to 5.2 eV depending simply on their structure and, in turn, on their degree of electron delocalization. This feature makes them ideal candidates for future bandgap engineering not only for photovoltaics, but also for many nano-electronic devices employing nothing else but silicon and hydrogen atoms.

  10. Engineering metal precipitate size distributions to enhance gettering in multicrystalline silicon

    Energy Technology Data Exchange (ETDEWEB)

    Hofstetter, Jasmin; Fenning, David P.; Buonassisi, Tonio [Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge MA, 02139 (United States); Lelievre, Jean-Francois [Universidad Politecnica de Madrid, Avd. Complutense s/n, 28040 Madrid (Spain); Del Canizo, Carlos [Centro de Tecnologia del Silicio Solar CENTESIL, Getafe (Spain)

    2012-10-15

    The extraction of metal impurities during phosphorus diffusion gettering (PDG) is one of the crucial process steps when fabricating high-efficiency solar cells using low-cost, lower-purity silicon wafers. In this work, we show that for a given metal concentration, the size and density of metal silicide precipitates strongly influences the gettering efficacy. Different precipitate size distributions can be already found in silicon wafers grown by different techniques. In our experiment, however, the as-grown distribution of precipitated metals in multicrystalline Si sister wafers is engineered through different annealing treatments in order to control for the concentration and distribution of other defects. A high density of small precipitates is formed during a homogenization step, and a lower density of larger precipitates is formed during extended annealing at 740 C. After PDG, homogenized samples show a decreased interstitial iron concentration compared to as-grown and ripened samples, in agreement with simulations. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. High-Performance Silicon Battery Anodes Enabled by Engineering Graphene Assemblies.

    Science.gov (United States)

    Zhou, Min; Li, Xianglong; Wang, Bin; Zhang, Yunbo; Ning, Jing; Xiao, Zhichang; Zhang, Xinghao; Chang, Yanhong; Zhi, Linjie

    2015-09-01

    We propose a novel material/electrode design formula and develop an engineered self-supporting electrode configuration, namely, silicon nanoparticle impregnated assemblies of templated carbon-bridged oriented graphene. We have demonstrated their use as binder-free lithium-ion battery anodes with exceptional lithium storage performances, simultaneously attaining high gravimetric capacity (1390 mAh g(-1) at 2 A g(-1) with respect to the total electrode weight), high volumetric capacity (1807 mAh cm(-3) that is more than three times that of graphite anodes), remarkable rate capability (900 mAh g(-1) at 8 A g(-1)), excellent cyclic stability (0.025% decay per cycle over 200 cycles), and competing areal capacity (as high as 4 and 6 mAh cm(-2) at 15 and 3 mA cm(-2), respectively). Such combined level of performance is attributed to the templated carbon bridged oriented graphene assemblies involved. This engineered graphene bulk assemblies not only create a robust bicontinuous network for rapid transport of both electrons and lithium ions throughout the electrode even at high material mass loading but also allow achieving a substantially high material tap density (1.3 g cm(-3)). Coupled with a simple and flexible fabrication protocol as well as practically scalable raw materials (e.g., silicon nanoparticles and graphene oxide), the material/electrode design developed would propagate new and viable battery material/electrode design principles and opportunities for energy storage systems with high-energy and high-power characteristics.

  12. Polymeric complex micelle loaded with axially substituted silicon(Ⅳ) phthalocyanine

    Institute of Scientific and Technical Information of China (English)

    Bao Quan Huang

    2009-01-01

    A novel axially substituted silicon(IV) phthalocyanine,namely di-pyridyloxy axially substituted silicon(Ⅳ) phthalocyanine 2 was synthesized and characterized by UV/vis,IR,elemental analysis,MS as well as 1H NMR spectroscopy.Hydrophobic 2 was encapsulated by amphiphilic triblock copolymer poly[Nε-(benzyloxycarbonyl-lysine]-poly(ethylene glycol)-poly [Nε-(benzyl oxycarbonyl) (PLL(Z)-b-PEG-b-PLL(Z)) to form hydrophobic 2-loaded polymeric complex miceile (PIC) (2-loaded PIC).Atom force microscopy (AFM) image showed that 2-loaded PIC formed a spherical nanocarrier with approximately 35-50 nm in diameter.The fluorescence intensity and lifetime of 2-loaded PIC was significantly enhanced by the incorporation 2 into PIC nanocarrier.

  13. Advances in complex societal, environmental and engineered systems

    CERN Document Server

    Essaaidi, Mohammad

    2017-01-01

    This book addresses recent technological progress that has led to an increased complexity in many natural and artificial systems. The resulting complexity research due to the emergence of new properties and spatio-temporal interactions among a large number of system elements - and between the system and its environment - is the primary focus of this text. This volume is divided into three parts: Part one focuses on societal and ecological systems, Part two deals with approaches for understanding, modeling, predicting and mastering socio-technical systems, and Part three includes real-life examples. Each chapter has its own special features; it is a self-contained contribution of distinguished experts working on different fields of science and technology relevant to the study of complex systems. Advances in Complex Systems of Contemporary Reality: Societal, Environmental and Engineered Systems will provide postgraduate students, researchers and managers with qualitative and quantitative methods for handling th...

  14. Biological Computation as the Revolution of Complex Engineered Systems

    CERN Document Server

    Gómez-Cruz, Nelson Alfonso

    2011-01-01

    Provided that there is no theoretical frame for complex engineered systems (CES) as yet, this paper claims that bio-inspired engineering can help provide such a frame. Within CES bio-inspired systems play a key role. The disclosure from bio-inspired systems and biological computation has not been sufficiently worked out, however. Biological computation is to be taken as the processing of information by living systems that is carried out in polynomial time, i.e., efficiently; such processing however is grasped by current science and research as an intractable problem (for instance, the protein folding problem). A remark is needed here: P versus NP problems should be well defined and delimited but biological computation problems are not. The shift from conventional engineering to bio-inspired engineering needs bring the subject (or problem) of computability to a new level. Within the frame of computation, so far, the prevailing paradigm is still the Turing-Church thesis. In other words, conventional engineering...

  15. Role of metal/silicon semiconductor contact engineering for enhanced output current in micro-sized microbial fuel cells

    KAUST Repository

    Mink, Justine E.

    2013-11-25

    We show that contact engineering plays an important role to extract the maximum performance from energy harvesters like microbial fuel cells (MFCs). We experimented with Schottky and Ohmic methods of fabricating contact areas on silicon in an MFC contact material study. We utilized the industry standard contact material, aluminum, as well as a metal, whose silicide has recently been recognized for its improved performance in smallest scale integration requirements, cobalt. Our study shows that improvements in contact engineering are not only important for device engineering but also for microsystems. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Dispersion engineering and frequency comb generation in thin silicon nitride concentric microresonators.

    Science.gov (United States)

    Kim, Sangsik; Han, Kyunghun; Wang, Cong; Jaramillo-Villegas, Jose A; Xue, Xiaoxiao; Bao, Chengying; Xuan, Yi; Leaird, Daniel E; Weiner, Andrew M; Qi, Minghao

    2017-08-29

    Kerr nonlinearity-based frequency combs and solitons have been generated from on-chip microresonators. The initiation of the combs requires global or local anomalous dispersion which leads to many limitations, such as material choice, film thickness, and spectral ranges where combs can be generated, as well as fabrication challenges. Using a concentric racetrack-shaped resonator, we show that such constraints can be lifted and resonator dispersion can be engineered to be anomalous over moderately broad bandwidth. We demonstrate anomalous dispersion in a 300 nm thick silicon nitride film, suitable for semiconductor manufacturing but previously thought to result in waveguides with high normal dispersion. Together with a mode-selective, tapered coupling scheme, we generate coherent mode-locked frequency combs. Our method can realize anomalous dispersion for resonators at almost any wavelength and simultaneously achieve material and process compatibility with semiconductor manufacturing.Kerr frequency comb generation from microresonators requires anomalous dispersion, imposing restrictions on materials and resonator design. Here, Kim et al. propose a concentric racetrack-resonator design where the dispersion can be engineered to be anomalous via resonant mode coupling.

  17. Complex microstructure fabrication by integrating silicon anisotropic etching and UV-LIGA technology

    Institute of Scientific and Technical Information of China (English)

    Jing Xiangmeng; Chen Di; Huang Chuang; Chen Xiang; Liu Jingquan; Zhu Jun

    2007-01-01

    A fabrication method which integrates silicon anisotropic etching micromachining with UV-LIGA technology to make complex microstructures is presented.This proposod combined process enables the fabrication of high-aspect-ratio and three-dimensional(3D)microstmctures,which cannot be fabricated by silicon bulk micromachining or UV-LIGA alone.To demonstrate this combined method.the 100μm thick SU-8 micro gears were fabricated on the silicon convex square structure.which is 100μm×100μm×80μm in dimension.In the subsequent micro hot embossing process,a novel type of plastics polyethylene terephtalate glycol(PETG)Was tried for use.Through optimizing process parameters,PETG shows the potential of being used as plastic replica in micro-electro-mechanical system(MEMS).This fabrication technology provides a new option for the increasing need of functionality,quality and economy of MEMS.

  18. The role of point defects and defect complexes in silicon device processing. Summary report and papers

    Energy Technology Data Exchange (ETDEWEB)

    Sopori, B.; Tan, T.Y.

    1994-08-01

    This report is the summary of the third workshop on the role of point defects and defect complexes in silicon device processing. The workshop was organized: (1) to discuss recent progress in the material quality produced by photovoltaic Si manufacturers, (2) to foster the understanding of point defect issues in Si device processing, (3) to review the effects of inhomogeneities on large- area solar cell performance, (4) to discuss how to improve Si solar cell processing, and (5) to develop a new understanding of gettering, defect passivation, and defect annihilation. Separate abstract were prepared for the individual papers, for the database.

  19. Novel scalable silicone elastomer and poly(2-hydroxyethyl methacrylate) (PHEMA) composite materials for tissue engineering and drug delivery applications

    DEFF Research Database (Denmark)

    Mohanty, Soumyaranjan; Hemmingsen, Mette; Wojcik, Magdalena

    2013-01-01

    In recent years hydrogels have received increasing attention as potential materials for applications in regenerative medicine. They can be used for scaffold materials providing structural integrity to tissue constructs, for controlled delivery of drugs and proteins to cell and tissues......, and for support materials in tissue growth. However, the real challenge is to obtain sufficiently good mechanical properties of the hydrogel. The present study shows the combination of two normally non-compatible materials, silicone elastomer and poly(2-hydroxyethyl methacrylate) (PHEMA), into a novel composite...... material with increased hydrophilicity in regard to virgin silicone elastomer, making it suitable as a scaffold for tissue engineering and with the concomitant possibility for delivering drug from the scaffold to the tissue. Interpenetrating polymer networks (IPNs) of silicone elastomer and PHEMA...

  20. Band-gap engineering by molecular mechanical strain-induced giant tuning of the luminescence in colloidal amorphous porous silicon nanostructures

    KAUST Repository

    Mughal, Asad Jahangir

    2014-01-01

    Nano-silicon is a nanostructured material in which quantum or spatial confinement is the origin of the material\\'s luminescence. When nano-silicon is broken into colloidal crystalline nanoparticles, its luminescence can be tuned across the visible spectrum only when the sizes of the nanoparticles, which are obtained via painstaking filtration methods that are difficult to scale up because of low yield, vary. Bright and tunable colloidal amorphous porous silicon nanostructures have not yet been reported. In this letter, we report on a 100 nm modulation in the emission of freestanding colloidal amorphous porous silicon nanostructures via band-gap engineering. The mechanism responsible for this tunable modulation, which is independent of the size of the individual particles and their distribution, is the distortion of the molecular orbitals by a strained silicon-silicon bond angle. This mechanism is also responsible for the amorphous-to-crystalline transformation of silicon. This journal is

  1. Band-gap engineering by molecular mechanical strain-induced giant tuning of the luminescence in colloidal amorphous porous silicon nanostructures.

    Science.gov (United States)

    Mughal, A; El Demellawi, J K; Chaieb, Sahraoui

    2014-12-14

    Nano-silicon is a nanostructured material in which quantum or spatial confinement is the origin of the material's luminescence. When nano-silicon is broken into colloidal crystalline nanoparticles, its luminescence can be tuned across the visible spectrum only when the sizes of the nanoparticles, which are obtained via painstaking filtration methods that are difficult to scale up because of low yield, vary. Bright and tunable colloidal amorphous porous silicon nanostructures have not yet been reported. In this letter, we report on a 100 nm modulation in the emission of freestanding colloidal amorphous porous silicon nanostructures via band-gap engineering. The mechanism responsible for this tunable modulation, which is independent of the size of the individual particles and their distribution, is the distortion of the molecular orbitals by a strained silicon-silicon bond angle. This mechanism is also responsible for the amorphous-to-crystalline transformation of silicon.

  2. Effects of nanoscale features on infrared radiative properties of heavily doped silicon complex gratings

    Institute of Scientific and Technical Information of China (English)

    HSU; PeiFeng

    2010-01-01

    The infrared radiative properties of one heavily doped silicon complex grating and its corresponding four modified complex gratings with attached features at transverse magnetic wave incidence were numerically investigated by employing the finite-difference time-domain method.For the complex grating,by properly choosing the carrier concentration and geometry,it exhibited a broadband absorptance peak at wavelengths between 7 and 12μm resulting from the excitation of surface plasmon polaritons.As for the four modified complex gratings,though absorptance spectra of the gratings almost remained unchanged, their locations shifted towards longer wavelengths.Meanwhile,the spectral absorptance peaks of two modified complex gratings were wider than that of the grating without attached features.Such broadened peaks could be partly attributed to the cavity resonance within the grating structures demonstrated by the electromagnetic fields and Poynting vectors plots.Finally,through comparing the spectral absorptances of complex gratings with two symmetrical square features in three sizes,it was shown that the peak wavelength shifted toward longer wavelengths with enlarged feature size.This work theoretically laid a foundation for the optimized design and application of the infrared detector with high performance.

  3. Complex quantum networks as structured environments: engineering and probing

    Science.gov (United States)

    Nokkala, Johannes; Galve, Fernando; Zambrini, Roberta; Maniscalco, Sabrina; Piilo, Jyrki

    2016-05-01

    We consider structured environments modeled by bosonic quantum networks and investigate the probing of their spectral density, structure, and topology. We demonstrate how to engineer a desired spectral density by changing the network structure. Our results show that the spectral density can be very accurately detected via a locally immersed quantum probe for virtually any network configuration. Moreover, we show how the entire network structure can be reconstructed by using a single quantum probe. We illustrate our findings presenting examples of spectral densities and topology probing for networks of genuine complexity.

  4. Evidence for an iron-hydrogen complex in p-type silicon

    Science.gov (United States)

    Leonard, S.; Markevich, V. P.; Peaker, A. R.; Hamilton, B.; Murphy, J. D.

    2015-07-01

    Interactions of hydrogen with iron have been studied in Fe contaminated p-type Czochralski silicon using capacitance-voltage profiling and deep level transient spectroscopy (DLTS). Hydrogen has been introduced into the samples from a silicon nitride layer grown by plasma enhanced chemical vapor deposition. After annealing of the Schottky diodes on Si:Fe + H samples under reverse bias in the temperature range of 90-120 °C, a trap has been observed in the DLTS spectra which we have assigned to a Fe-H complex. The trap is only observed when a high concentration of hydrogen is present in the near surface region. The trap concentration is higher in samples with a higher concentration of single interstitial Fe atoms. The defect has a deep donor level at Ev + 0.31 eV. Direct measurements of capture cross section of holes have shown that the capture cross section is not temperature dependent and its value is 5.2 × 10-17 cm2. It is found from an isochronal annealing study that the Fe-H complex is not very stable and can be eliminated completely by annealing for 30 min at 125 °C.

  5. Microscopic structure and reorientation kinetics of B-H complexes in silicon

    Science.gov (United States)

    Noya, José C.; Herrero, Carlos P.; Ramírez, Rafael

    1997-12-01

    Structural and dynamical properties of hydrogen and deuterium in boron-doped silicon have been studied by the path-integral Monte Carlo method as a function of temperature in the range between 30 and 400 K. The Si-Si and Si-B interactions were modeled by Stillinger-Weber-type potentials, and the Si-H and B-H interactions were parametrized by following the results of earlier pseudopotential-density-functional calculations for this system. Impurity energy, nuclei delocalization, and lattice relaxation are analyzed, the latter resulting to be mass dependent. The reorientation rate of the complex is obtained from quantum transition-state theory. A break in the slope of the Arrhenius plot for the jump rate of hydrogen is obtained at T~60 K, indicating a crossover from thermally activated quasiclassical motion over a barrier to thermally assisted quantum tunneling, in good agreement with previous experimental results. For deuterium, this deviation from an Arrhenius law is found at T~35 K. Both the impurity and the host nuclei are treated quantum mechanically, and it is shown that the defect complex undergoing quantum tunneling consists of hydrogen, boron, and the nearest silicon atoms.

  6. Processing and characterization of diatom nanoparticles and microparticles as potential source of silicon for bone tissue engineering.

    Science.gov (United States)

    Le, Thi Duy Hanh; Bonani, Walter; Speranza, Giorgio; Sglavo, Vincenzo; Ceccato, Riccardo; Maniglio, Devid; Motta, Antonella; Migliaresi, Claudio

    2016-02-01

    Silicon plays an important role in bone formation and maintenance, improving osteoblast cell function and inducing mineralization. Often, bone deformation and long bone abnormalities have been associated with silica/silicon deficiency. Diatomite, a natural deposit of diatom skeleton, is a cheap and abundant source of biogenic silica. The aim of the present study is to validate the potential of diatom particles derived from diatom skeletons as silicon-donor materials for bone tissue engineering applications. Raw diatomite (RD) and calcined diatomite (CD) powders were purified by acid treatments, and diatom microparticles (MPs) and nanoparticles (NPs) were produced by fragmentation of purified diatoms under alkaline conditions. The influence of processing on the surface chemical composition of purified diatomites was evaluated by X-ray photoelectron spectroscopy (XPS). Diatoms NPs were also characterized in terms of morphology and size distribution by transmission electron microscopy (TEM) and Dynamic light scattering (DLS), while diatom MPs morphology was analyzed by scanning electron microscopy (SEM). Surface area and microporosity of the diatom particles were evaluated by nitrogen physisorption methods. Release of silicon ions from diatom-derived particles was demonstrated using inductively coupled plasma optical emission spectrometry (ICP/OES); furthermore, silicon release kinetic was found to be influenced by diatomite purification method and particle size. Diatom-derived microparticles (MPs) and nanoparticles (NPs) showed limited or no cytotoxic effect in vitro depending on the administration conditions.

  7. Engineering complex topological memories from simple Abelian models

    Science.gov (United States)

    Wootton, James R.; Lahtinen, Ville; Doucot, Benoit; Pachos, Jiannis K.

    2011-09-01

    In three spatial dimensions, particles are limited to either bosonic or fermionic statistics. Two-dimensional systems, on the other hand, can support anyonic quasiparticles exhibiting richer statistical behaviors. An exciting proposal for quantum computation is to employ anyonic statistics to manipulate information. Since such statistical evolutions depend only on topological characteristics, the resulting computation is intrinsically resilient to errors. The so-called non-Abelian anyons are most promising for quantum computation, but their physical realization may prove to be complex. Abelian anyons, however, are easier to understand theoretically and realize experimentally. Here we show that complex topological memories inspired by non-Abelian anyons can be engineered in Abelian models. We explicitly demonstrate the control procedures for the encoding and manipulation of quantum information in specific lattice models that can be implemented in the laboratory. This bridges the gap between requirements for anyonic quantum computation and the potential of state-of-the-art technology.

  8. Green IT engineering concepts, models, complex systems architectures

    CERN Document Server

    Kondratenko, Yuriy; Kacprzyk, Janusz

    2017-01-01

    This volume provides a comprehensive state of the art overview of a series of advanced trends and concepts that have recently been proposed in the area of green information technologies engineering as well as of design and development methodologies for models and complex systems architectures and their intelligent components. The contributions included in the volume have their roots in the authors’ presentations, and vivid discussions that have followed the presentations, at a series of workshop and seminars held within the international TEMPUS-project GreenCo project in United Kingdom, Italy, Portugal, Sweden and the Ukraine, during 2013-2015 and at the 1st - 5th Workshops on Green and Safe Computing (GreenSCom) held in Russia, Slovakia and the Ukraine. The book presents a systematic exposition of research on principles, models, components and complex systems and a description of industry- and society-oriented aspects of the green IT engineering. A chapter-oriented structure has been adopted for this book ...

  9. Moisture-cured silicone-urethanes-candidate materials for tissue engineering: a biocompatibility study in vitro.

    Science.gov (United States)

    Mrówka, P; Kozakiewicz, J; Jurkowska, A; Sienkiewicz, E; Przybylski, J; Lewandowski, Z; Przybylski, J; Lewandowska-Szumieł, M

    2010-07-01

    This study was performed to verify the response of human bone-derived cells (HBDCs) to moisture-cured silicone-urethanes (mcSUUs) in vitro, as the first step toward using them as scaffolds for bone tissue engineering. Good surgical handling, tissue cavity filling, stable mechanical properties, and potentially improved oxygen supply to cells after implantation justify the investigation of these nondegradable elastomers. A set of various mcSUUs were obtained by moisture-curing NCO-terminated prepolymers, synthesized from oligomeric siloxane diols of two different oligosiloxane chain lengths, and two different diisocyanates (MDI and IPDI), using two different NCO/OH molar ratios. Dibutyltindilaurate (DBTL) or N-dimethylethanolamine (N-met) served as catalysts. After 7 days of culture, cell number, viability, and alkaline phosphatase (ALP) activity were determined, and after 21 days, cell viability and collagen production were determined. Material characteristics significantly influenced the cell response. The mcSUUs prepared with DBTL (widely used in the syntheses of biomaterials) were cytotoxic. The MDI-based mcSUUs were significantly more favored by HBDCs than the IPDI-based ones in all performed tests. MDI-based material with low 2/1 NCO/OH and short chain length was the best support for cells, comparable with tissue-culture polystyrene (with ALP activity even higher). HBDCs cultured on porous scaffolds from this mcSUU produced a tissue-like structure in culture. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010.

  10. Effect of swift heavy Kr ions on complex permittivity of silicon PIN diode

    Science.gov (United States)

    Li, Yun; Su, Ping; Yang, Zhimei; Ma, Yao; Gong, Min

    2016-12-01

    The complex permittivity has been researched on silicon PIN diodes irradiated by 2150 MeV heavy Kr ions in this article. The difference of complex permittivity spectra from 1 to 10^7 Hz between irradiated and unirradiated were observed and discussed. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics were measured at room temperature (300 K) to study the change of electrical properties in diode after irradiation. Deep level transient spectroscopy (DLTS) was used to investigate damages caused by 2150 MeV heavy Kr ions in diode. Two extra electron traps were observed, which were located at EC-0.31 eV and EC-0.17 eV. It indicated that new defects have been formed in PIN diode during irradiation. A comparison of the results illustrated that not only the carrier density but also the recombination of electron-hole pair have important influences on the properties of complex permittivity. These results offer a further indication of the mechanism about the complex permittivity property of semiconductor device, which could help to make the applications for the semiconductor device controlled by electric signals come true in the fields of optoelectronic integrated circuits, plasma antenna and so on.

  11. Processing and characterization of diatom nanoparticles and microparticles as potential source of silicon for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Le, Thi Duy Hanh [Department of Industrial Engineering, University of Trento, Trento (Italy); BIOtech Research Center and European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Trento (Italy); Bonani, Walter [Department of Industrial Engineering, University of Trento, Trento (Italy); BIOtech Research Center and European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Trento (Italy); Interuniversity Consortium for Science and Technology of Materials, Trento Research Unit, Trento (Italy); Speranza, Giorgio [Center for Materials and Microsystems, PAM-SE, Fondazione Bruno Kessler, Trento (Italy); Sglavo, Vincenzo; Ceccato, Riccardo [Department of Industrial Engineering, University of Trento, Trento (Italy); Maniglio, Devid; Motta, Antonella [Department of Industrial Engineering, University of Trento, Trento (Italy); BIOtech Research Center and European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Trento (Italy); Interuniversity Consortium for Science and Technology of Materials, Trento Research Unit, Trento (Italy); Migliaresi, Claudio, E-mail: claudio.migliaresi@unitn.it [Department of Industrial Engineering, University of Trento, Trento (Italy); BIOtech Research Center and European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Trento (Italy); Interuniversity Consortium for Science and Technology of Materials, Trento Research Unit, Trento (Italy)

    2016-02-01

    Silicon plays an important role in bone formation and maintenance, improving osteoblast cell function and inducing mineralization. Often, bone deformation and long bone abnormalities have been associated with silica/silicon deficiency. Diatomite, a natural deposit of diatom skeleton, is a cheap and abundant source of biogenic silica. The aim of the present study is to validate the potential of diatom particles derived from diatom skeletons as silicon-donor materials for bone tissue engineering applications. Raw diatomite (RD) and calcined diatomite (CD) powders were purified by acid treatments, and diatom microparticles (MPs) and nanoparticles (NPs) were produced by fragmentation of purified diatoms under alkaline conditions. The influence of processing on the surface chemical composition of purified diatomites was evaluated by X-ray photoelectron spectroscopy (XPS). Diatoms NPs were also characterized in terms of morphology and size distribution by transmission electron microscopy (TEM) and Dynamic light scattering (DLS), while diatom MPs morphology was analyzed by scanning electron microscopy (SEM). Surface area and microporosity of the diatom particles were evaluated by nitrogen physisorption methods. Release of silicon ions from diatom-derived particles was demonstrated using inductively coupled plasma optical emission spectrometry (ICP/OES); furthermore, silicon release kinetic was found to be influenced by diatomite purification method and particle size. Diatom-derived microparticles (MPs) and nanoparticles (NPs) showed limited or no cytotoxic effect in vitro depending on the administration conditions. - Highlights: • Diatomite is a natural source of silica and has a potential as silicon-donor for bone regenerative applications. • Diatom particles derived from purified diatom skeletons were prepared by fragmentation under extreme alkaline condition. • Dissolution of diatom particles derived from diatom skeletons in DI water depend on purification method

  12. Engineered valley-orbit splittings in quantum-confined nanostructures in silicon

    NARCIS (Netherlands)

    Rahman, R.; Verduijn, J.; Kharche, N.; Lansbergen, G.P.; Klimeck, G.; Hollenberg, L.C.L.; Rogge, S.

    2011-01-01

    An important challenge in silicon quantum electronics in the few electron regime is the potentially small energy gap between the ground and excited orbital states in 3D quantum confined nanostructures due to the multiple valley degeneracies of the conduction band present in silicon. Understanding th

  13. New software engineering paradigm based on complexity science an introduction to NSE

    CERN Document Server

    Xiong, Jay

    2011-01-01

    This book describes a revolution in software engineering - the Nonlinear Software Engineering paradigm, which complies with the essential principles of complexity science and can help double productivity, halve costs and reduce defects in software products.

  14. Highly Manufacturable Deep (Sub-Millimeter) Etching Enabled High Aspect Ratio Complex Geometry Lego-Like Silicon Electronics

    KAUST Repository

    Ghoneim, Mohamed T.

    2017-02-01

    A highly manufacturable deep reactive ion etching based process involving a hybrid soft/hard mask process technology shows high aspect ratio complex geometry Lego-like silicon electronics formation enabling free-form (physically flexible, stretchable, and reconfigurable) electronic systems.

  15. Analytical and experimental evaluation of joining silicon nitride to metal and silicon carbide to metal for advanced heat engine applications. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kang, S.; Selverian, J.H.; O`Neil, D.; Kim, H. [GTE Labs., Inc., Waltham, MA (US); Kim, K. [Brown Univ., Providence, RI (US). Div. of Engineering

    1993-05-01

    This report summarizes the results of Phase 2 of Analytical and Experimental Evaluation of Joining Silicon Nitride to Metal and Silicon Carbide to Metal for Advanced Heat Engine Applications. A general methodology was developed to optimize the joint geometry and material systems for 650{degrees}C applications. Failure criteria were derived to predict the fracture of the braze and ceramic. Extensive finite element analyses (FEA) were performed to examine various joint geometries and to evaluate the affect of different interlayers on the residual stress state. Also, material systems composed of coating materials, interlayers, and braze alloys were developed for the program based on the chemical stability and strength of the joints during processing, and service. The FEA results were compared with experiments using two methods: (1) an idealized strength relationship of the ceramic, and (2) a probabilistic analysis of the ceramic strength (NASA CARES). The results showed that the measured strength of the joint reached 30--80% of the strength predicted by FEA. Also, potential high-temperature braze alloys were developed and evaluated for the high-temperature application of ceramic-metal joints. 38 tabs, 29 figs, 20 refs.

  16. Core-Shell Coating Silicon Anode Interfaces with Coordination Complex for Stable Lithium-Ion Batteries.

    Science.gov (United States)

    Zhou, Jinqiu; Qian, Tao; Wang, Mengfan; Xu, Na; Zhang, Qi; Li, Qun; Yan, Chenglin

    2016-03-02

    In situ core-shell coating was used to improve the electrochemical performance of Si-based anodes with polypyrrole-Fe coordination complex. The vast functional groups in the organometallic coordination complex easily formed hydrogen bonds when in situ modifying commercial Si nanoparticles. The incorporation of polypyrrole-Fe resulted in the conformal conductive coating surrounding each Si nanoparticle, not only providing good electrical connection to the particles but also promoting the formation of a stable solid-electrolyte-interface layer on the Si electrode surface, enhancing the cycling properties. As an anode material for Li-ion batteries, modified silicon powders exhibited high reversible capacity (3567 mAh/g at 0.3 A/g), good rate property (549.12 mAh/g at 12 A/g), and excellent cycling performance (reversible capacity of 1500 mAh/g after 800 cycles at 1.2 A/g). The constructed novel concept of core-shell coating Si particles presented a promising route for facile and large-scale production of Si-based anodes for extremely durable Li-ion batteries, which provided a wide range of applications in the field of energy storage of the renewable energy derived from the solar energy, hydropower, tidal energy, and geothermal heat.

  17. Solubilization of silica: Synthesis, characterization and study of penta-coordinated pyridine N-oxide silicon complexes

    Indian Academy of Sciences (India)

    Subramania Ranganathan; Ch Chandrashekhar Rao; Suvarchala Devi Vudayagiri; Y B R D Rajesh; B Jagadeesh

    2004-03-01

    In an effort to design agents that could solubilize silica in water, under ambient conditions and pH, as takes place in nature, novel zwitterionic, penta-oxo-coordinated silicon compounds with siliconate cores have been prepared from 4-substituted pyridine N-oxides (H, OMe, morpholino, NO2) as donor ligands, their structures established by 1H, 13C and MS, and the coordination number of silicon, by 29Si NMR. The formation of complexes from pyridine N-oxides is noteworthy since they arise from interaction with a weakly nucleophilic oxygen centre. The ability of the pyridine N-oxides to enhance the solubilization of silica in water has been experimentally demonstrated. Possible rationalization of this observation on the basis of O→Si coordination via the oxygen atom of pyridine N-oxide is suggested.

  18. Rear interface engineering of hybrid organic-silicon nanowire solar cells via blade coating.

    Science.gov (United States)

    Lai, Yi-Chun; Chang, Yu-Fan; Tsai, Pei-Ting; Chang, Jan-kai; Tseng, Wei-Hsuan; Lin, Yi-Cheng; Hsiao, Chu-Yen; Zan, Hsiao-Wen; Wu, Chih-I; Chi, Gou-Chung; Meng, Hsin-Fei; Yu, Peichen

    2016-01-25

    In this work, we investigate blade-coated organic interlayers at the rear surface of hybrid organic-silicon photovoltaics based on two small molecules: Tris(8-hydroxyquinolinato) aluminium (Alq(3)) and 1,3-bis(2-(4-tert-butylphenyl)-1,3,4-oxadiazol-5-yl) benzene (OXD-7). In particular, soluble Alq(3) resulting in a uniform thin film with a root-mean-square roughness organic-silicon photovoltaics.

  19. Laser-induced ferroelectric domain engineering in LiNbO3 crystals using an amorphous silicon overlayer

    Science.gov (United States)

    Zisis, G.; Martinez-Jimenez, G.; Franz, Y.; Healy, N.; Masaud, T. M.; Chong, H. M. H.; Soergel, E.; Peacock, A. C.; Mailis, S.

    2017-08-01

    We report laser-induced poling inhibition and direct poling in lithium niobate crystals (LiNbO3), covered with an amorphous silicon (a-Si) light-absorbing layer, using a visible (488 nm) continuous wave laser source. Our results show that the use of the a-Si overlayer produces deeper poling inhibited domains with minimum surface damage, as compared to previously reported UV laser writing experiments on uncoated crystals, thus increasing the applicability of this method in the production of ferroelectric domain engineered structures for nonlinear optical applications. The characteristics of the poling inhibited domains were investigated using differential etching and piezoresponse force microscopy.

  20. Simple, Complex, Innovative: Design Education at Civil Engineering

    NARCIS (Netherlands)

    Van Nederveen, G.A.; Soons, F.A.M.; Suddle, S.I.; De Ridder, H.

    2011-01-01

    In faculties such as Civil Engineering, design is a not a core activity. Core activities at Civil Engineering are structural engineering, structural analysis, mechanics, fluid dynamics, etc. Design education has a relatively small share in the curriculum, compared to faculties such as Industrial

  1. Integrated modeling tool for performance engineering of complex computer systems

    Science.gov (United States)

    Wright, Gary; Ball, Duane; Hoyt, Susan; Steele, Oscar

    1989-01-01

    This report summarizes Advanced System Technologies' accomplishments on the Phase 2 SBIR contract NAS7-995. The technical objectives of the report are: (1) to develop an evaluation version of a graphical, integrated modeling language according to the specification resulting from the Phase 2 research; and (2) to determine the degree to which the language meets its objectives by evaluating ease of use, utility of two sets of performance predictions, and the power of the language constructs. The technical approach followed to meet these objectives was to design, develop, and test an evaluation prototype of a graphical, performance prediction tool. The utility of the prototype was then evaluated by applying it to a variety of test cases found in the literature and in AST case histories. Numerous models were constructed and successfully tested. The major conclusion of this Phase 2 SBIR research and development effort is that complex, real-time computer systems can be specified in a non-procedural manner using combinations of icons, windows, menus, and dialogs. Such a specification technique provides an interface that system designers and architects find natural and easy to use. In addition, PEDESTAL's multiview approach provides system engineers with the capability to perform the trade-offs necessary to produce a design that meets timing performance requirements. Sample system designs analyzed during the development effort showed that models could be constructed in a fraction of the time required by non-visual system design capture tools.

  2. Subwavelength engineered fiber-to-chip silicon-on-sapphire interconnects for mid-infrared applications (Conference Presentation)

    Science.gov (United States)

    Alonso-Ramos, Carlos; Han, Zhaohong; Le Roux, Xavier; Lin, Hongtao; Singh, Vivek; Lin, Pao Tai; Tan, Dawn; Cassan, Eric; Marris-Morini, Delphine; Vivien, Laurent; Wada, Kazumi; Hu, Juejun; Agarwal, Anuradha; Kimerling, Lionel C.

    2016-05-01

    The mid-Infrared wavelength range (2-20 µm), so-called fingerprint region, contains the very sharp vibrational and rotational resonances of many chemical and biological substances. Thereby, on-chip absorption-spectrometry-based sensors operating in the mid-Infrared (mid-IR) have the potential to perform high-precision, label-free, real-time detection of multiple target molecules within a single sensor, which makes them an ideal technology for the implementation of lab-on-a-chip devices. Benefiting from the great development realized in the telecom field, silicon photonics is poised to deliver ultra-compact efficient and cost-effective devices fabricated at mass scale. In addition, Si is transparent up to 8 µm wavelength, making it an ideal material for the implementation of high-performance mid-IR photonic circuits. The silicon-on-insulator (SOI) technology, typically used in telecom applications, relies on silicon dioxide as bottom insulator. Unfortunately, silicon dioxide absorbs light beyond 3.6 µm, limiting the usability range of the SOI platform for the mid-IR. Silicon-on-sapphire (SOS) has been proposed as an alternative solution that extends the operability region up to 6 µm (sapphire absorption), while providing a high-index contrast. In this context, surface grating couplers have been proved as an efficient means of injecting and extracting light from mid-IR SOS circuits that obviate the need of cleaving sapphire. However, grating couplers typically have a reduced bandwidth, compared with facet coupling solutions such as inverse or sub-wavelength tapers. This feature limits their feasibility for absorption spectroscopy applications that may require monitoring wide wavelength ranges. Interestingly, sub-wavelength engineering can be used to substantially improve grating coupler bandwidth, as demonstrated in devices operating at telecom wavelengths. Here, we report on the development of fiber-to-chip interconnects to ZrF4 optical fibers and integrated SOS

  3. Engineering

    National Research Council Canada - National Science Library

    Includes papers in the following fields: Aerospace Engineering, Agricultural Engineering, Chemical Engineering, Civil Engineering, Electrical Engineering, Environmental Engineering, Industrial Engineering, Materials Engineering, Mechanical...

  4. Selected Topics on Managing Complexity and Information Systems Engineering: Editorial Introduction to Issue 8 of CSIMQ

    Directory of Open Access Journals (Sweden)

    Peter Forbrig

    2016-10-01

    Full Text Available Business process models greatly contribute to analyze and understand the activities of enterprises. However, it is still a challenge to cope with the complexity of systems specifications and their requirements. This issue of the journal of Complex Systems Informatics and Modeling (CSIMQ presents papers that discuss topics on managing complexity and information systems engineering. The papers are extended versions of selected papers from the workshop on Continuous Requirements Engineering held at the requirements engineering conference REFSQ 2016 in Gothenburg, the workshop on Managed Complexity held at the business informatics conference BIR 2016 in Prague, and the CAiSE 2016 Forum held in Ljubljana.

  5. The complex interface chemistry of thin-film silicon/zinc oxide solar cell structures.

    Science.gov (United States)

    Gerlach, D; Wimmer, M; Wilks, R G; Félix, R; Kronast, F; Ruske, F; Bär, M

    2014-12-21

    The interface between solid-phase crystallized phosphorous-doped polycrystalline silicon (poly-Si(n(+))) and aluminum-doped zinc oxide (ZnO:Al) was investigated using spatially resolved photoelectron emission microscopy. We find the accumulation of aluminum in the proximity of the interface. Based on a detailed photoemission line analysis, we also suggest the formation of an interface species. Silicon suboxide and/or dehydrated hemimorphite have been identified as likely candidates. For each scenario a detailed chemical reaction pathway is suggested. The chemical instability of the poly-Si(n(+))/ZnO:Al interface is explained by the fact that SiO2 is more stable than ZnO and/or that H2 is released from the initially deposited a-Si:H during the crystallization process. As a result, Zn (a deep acceptor in silicon) is "liberated" close to the silicon/zinc oxide interface presenting the inherent risk of forming deep defects in the silicon absorber. These could act as recombination centers and thus limit the performance of silicon/zinc oxide based solar cells. Based on this insight some recommendations with respect to solar cell design, material selection, and process parameters are given for further knowledge-based thin-film silicon device optimization.

  6. Dielectric engineering: Characterization, development and process damage minimization of various silicon oxides

    NARCIS (Netherlands)

    Ackaert, Jan Germain Gabriel

    2004-01-01

    Over the various chapters, this thesis describes the characterization and development of a number of applications of silicon dioxides. An oxynitride is developed allowing a much higher SiGe epitaxial deposition rate in a bipolar process. Also a tunneloxide for non volatile memory application is

  7. Bandgap and Carrier Transport Engineering of Quantum Confined Mixed Phase Nanocrystalline/Amorphous Silicon

    Energy Technology Data Exchange (ETDEWEB)

    Guan, Tianyuan; Klafehn, Grant; Kendrick, Chito; Theingi, San; Airuoyo, Idemudia; Lusk, Mark T.; Stradins, Paul; Taylor, Craig; Collins, Reuben T.

    2016-11-21

    Mixed phase nanocrystalline/amorphous-silicon (nc/a-Si:H) thin films with band-gap higher than bulk silicon are prepared by depositing silicon nanoparticles (SiNPs), prepared in a separate deposition zone, and hydrogenated amorphous silicon (a-Si:H), simultaneously. Since the two deposition phases are well decoupled, optimized parameters for each component can apply to the growth process. Photoluminescence spectroscopy (PL) shows that the embedded SiNPs are small enough to exhibit quantum confinement effects. The low temperature PL measurements on the mixed phase reveal a dominant emission feature, which is associated with SiNPs surrounded by a-Si:H. In addition, we compare time dependent low temperature PL measurements for both a-Si:H and mixed phase material under intensive laser exposure for various times up to two hours. The PL intensity of a-Si:H with embedded SiNPs degrades much less than that of pure a-Si:H. We propose this improvement of photostability occurs because carriers generated in the a-Si:H matrix quickly transfer into SiNPs and recombine there instead of recombining in a-Si:H and creating defect states (Staebler-Wronski Effect).

  8. Requirements engineering: the key to designing complex medical systems.

    Science.gov (United States)

    Carr, J J; McCullough, C E

    2000-01-01

    A variety of business systems, clinical work systems, instrumentation systems, information systems, infrastructure systems, and management systems interact to make the modern healthcare facility work. The key to designing for such a system is systems engineering, a skill often little appreciated among clinical engineers. At the heart of systems engineering is requirements engineering and management (REAM), which is defined as "the process of discovering, documenting and managing systems requirements." The principal activities of REAM include eliciting, understanding, negotiating, describing, validating, and managing system requirements. When REAM is done improperly, the resulting system will be satisfactory only if chance intervenes. Well-done REAM is likely to bring the project in on time, under budget, and at full performance.

  9. Tuning thermal transport in ultrathin silicon membranes by surface nanoscale engineering.

    Science.gov (United States)

    Neogi, Sanghamitra; Reparaz, J Sebastian; Pereira, Luiz Felipe C; Graczykowski, Bartlomiej; Wagner, Markus R; Sledzinska, Marianna; Shchepetov, Andrey; Prunnila, Mika; Ahopelto, Jouni; Sotomayor-Torres, Clivia M; Donadio, Davide

    2015-04-28

    A detailed understanding of the connections of fabrication and processing to structural and thermal properties of low-dimensional nanostructures is essential to design materials and devices for phononics, nanoscale thermal management, and thermoelectric applications. Silicon provides an ideal platform to study the relations between structure and heat transport since its thermal conductivity can be tuned over 2 orders of magnitude by nanostructuring. Combining realistic atomistic modeling and experiments, we unravel the origin of the thermal conductivity reduction in ultrathin suspended silicon membranes, down to a thickness of 4 nm. Heat transport is mostly controlled by surface scattering: rough layers of native oxide at surfaces limit the mean free path of thermal phonons below 100 nm. Removing the oxide layers by chemical processing allows us to tune the thermal conductivity over 1 order of magnitude. Our results guide materials design for future phononic applications, setting the length scale at which nanostructuring affects thermal phonons most effectively.

  10. Methods Used to Support a Life Cycle of Complex Engineering Products

    Science.gov (United States)

    Zakharova, Alexandra A.; Kolegova, Olga A.; Nekrasova, Maria E.; Eremenko, Andrey O.

    2016-08-01

    Management of companies involved in the design, development and operation of complex engineering products recognize the relevance of creating systems for product lifecycle management. A system of methods is proposed to support life cycles of complex engineering products, based on fuzzy set theory and hierarchical analysis. The system of methods serves to demonstrate the grounds for making strategic decisions in an environment of uncertainty, allows the use of expert knowledge, and provides interconnection of decisions at all phases of strategic management and all stages of a complex engineering product lifecycle.

  11. Complex Problem Exercises in Developing Engineering Students' Conceptual and Procedural Knowledge of Electromagnetics

    Science.gov (United States)

    Leppavirta, J.; Kettunen, H.; Sihvola, A.

    2011-01-01

    Complex multistep problem exercises are one way to enhance engineering students' learning of electromagnetics (EM). This study investigates whether exposure to complex problem exercises during an introductory EM course improves students' conceptual and procedural knowledge. The performance in complex problem exercises is compared to prior success…

  12. Versatile Particle-Based Route to Engineer Vertically Aligned Silicon Nanowire Arrays and Nanoscale Pores.

    Science.gov (United States)

    Elnathan, Roey; Isa, Lucio; Brodoceanu, Daniel; Nelson, Adrienne; Harding, Frances J; Delalat, Bahman; Kraus, Tobias; Voelcker, Nicolas H

    2015-10-28

    Control over particle self-assembly is a prerequisite for the colloidal templating of lithographical etching masks to define nanostructures. This work integrates and combines for the first time bottom-up and top-down approaches, namely, particle self-assembly at liquid-liquid interfaces and metal-assisted chemical etching, to generate vertically aligned silicon nanowire (VA-SiNW) arrays and, alternatively, arrays of nanoscale pores in a silicon wafer. Of particular importance, and in contrast to current techniques, including conventional colloidal lithography, this approach provides excellent control over the nanowire or pore etching site locations and decouples nanowire or pore diameter and spacing. The spacing between pores or nanowires is tuned by adjusting the specific area of the particles at the liquid-liquid interface before deposition. Hence, the process enables fast and low-cost fabrication of ordered nanostructures in silicon and can be easily scaled up. We demonstrate that the fabricated VA-SiNW arrays can be used as in vitro transfection platforms for transfecting human primary cells.

  13. Silicon photonics III systems and applications

    CERN Document Server

    Lockwood, David

    2016-01-01

    This book is volume III of a series of books on silicon photonics. It reports on the development of fully integrated systems where many different photonics component are integrated together to build complex circuits. This is the demonstration of the fully potentiality of silicon photonics. It contains a number of chapters written by engineers and scientists of the main companies, research centers and universities active in the field. It can be of use for all those persons interested to know the potentialities and the recent applications of silicon photonics both in microelectronics, telecommunication and consumer electronics market.

  14. Follow the Money: Engineering at Stanford and UC Berkeley during the Rise of Silicon Valley

    Science.gov (United States)

    Adams, Stephen B.

    2009-01-01

    A comparison of the engineering schools at UC Berkeley and Stanford during the 1940s and 1950s shows that having an excellent academic program is necessary but not sufficient to make a university entrepreneurial (an engine of economic development). Key factors that made Stanford more entrepreneurial than Cal during this period were superior…

  15. Iron-oxygen interaction in silicon: A combined XBIC/XRF-EBIC-DLTS study of precipitation and complex building

    Energy Technology Data Exchange (ETDEWEB)

    Trushin, M., E-mail: trushmax@tu-cottbus.d [IHP/BTU Jointlab, Konrad-Wachsmann Allee 1, 03046 Cottbus (Germany); Vyvenko, O. [V.A.Fok Institute of Physics, St. Petersburg State University, Ulyanovskaya 1, 108594 St. Petersburg (Russian Federation); Seifert, W. [IHP/BTU Jointlab, Konrad-Wachsmann Allee 1, 03046 Cottbus (Germany); IHP microelectronics, Im Technologiepark 25, D-15236 Frankfurt (Oder) (Germany); Jia, G. [IHP/BTU Jointlab, Konrad-Wachsmann Allee 1, 03046 Cottbus (Germany); Kittler, M. [IHP/BTU Jointlab, Konrad-Wachsmann Allee 1, 03046 Cottbus (Germany); IHP microelectronics, Im Technologiepark 25, D-15236 Frankfurt (Oder) (Germany)

    2009-12-15

    Iron-oxygen interaction in the Czochralski-grown silicon (CZ-Si) giving rise to their final precipitated state was investigated by means of a combination of electrical and element-sensitive techniques. The samples studied were intentionally contaminated with iron at 1150 deg. C and then they were annealed at temperatures of 850 and 950 deg. C to stimulate precipitate formation. Fe-related defect levels in silicon band gap and spatial distributions of iron-related precipitates were monitored after each annealing step. It was found that FeB-pairs being the dominant defects in as-contaminated sample transformed completely to the stable FeO-related complexes that served as precursors for further iron-oxygen co-precipitation.

  16. Iron-oxygen interaction in silicon: A combined XBIC/XRF-EBIC-DLTS study of precipitation and complex building

    Science.gov (United States)

    Trushin, M.; Vyvenko, O.; Seifert, W.; Jia, G.; Kittler, M.

    2009-12-01

    Iron-oxygen interaction in the Czochralski-grown silicon (CZ-Si) giving rise to their final precipitated state was investigated by means of a combination of electrical and element-sensitive techniques. The samples studied were intentionally contaminated with iron at 1150 °C and then they were annealed at temperatures of 850 and 950 °C to stimulate precipitate formation. Fe-related defect levels in silicon band gap and spatial distributions of iron-related precipitates were monitored after each annealing step. It was found that FeB-pairs being the dominant defects in as-contaminated sample transformed completely to the stable FeO-related complexes that served as precursors for further iron-oxygen co-precipitation.

  17. FTRIFS biosensor based on double layer porous silicon as a LC detector for target molecule screening from complex samples.

    Science.gov (United States)

    Shang, Yunling; Zhao, Weijie; Xu, Erchao; Tong, Changlun; Wu, Jianmin

    2010-01-15

    Post-column identification of target compounds in complex samples is one of the major tasks in drug screening and discovery. In this work, we demonstrated that double layer porous silicon (PSi) attached with affinity ligand could serve as a sensing element for post-column detection of target molecule by Fourier transformed reflectometric interference spectroscopy (FTRIFS), in which trypsin and its inhibitor were used as the model probe-target system. The double layer porous silicon was prepared by electrical etching with a current density of 500 mA/cm(2), followed by 167 mA/cm(2). Optical measurements indicated that trypsin could infiltrate into the outer porous layer (porosity 83.6%), but was excluded by the bottom layer (porosity 52%). The outer layer, attached with trypsin by standard amino-silane and glutaraldehyde chemistry, could specifically bind with the trypsin inhibitor, acting as a sample channel, while the bottom layer served as a reference signal channel. The binding event between the attached trypsin and trypsin inhibitor samples could be detected by FTRIFS in real-time through monitoring the optical thickness change of the porous silicon layer. The baseline drift caused by sample matrix variation could be effectively eliminated by a signal correction method. Optical signals had a linear relationship with the concentration of trypsin inhibitor in the range of 10-200 ng mL(-1). The FTRIFS biosensor based on double layer porous silicon could be combined with a UV detector for screening the target molecule from complex component mixtures separated by a LC column. Using an LC-UV-FTRIFS system, a fraction containing a trypsin inhibitor could be separated from a soybean extract sample and identified in real-time.

  18. Analysis of Engineered Nanomaterials in Complex Matricies (Environment and Biota): General Considerations and Conceptual Case Studies

    Science.gov (United States)

    Advances in the study of the environmental fate, transport, and ecotoxicological effects of engineered nanomaterials (ENMs) have been hampered by a lack of adequate techniques for the detection and quantification of ENMs at environmentally relevant concentrations in complex media...

  19. A Complex Formula: Girls and Women in Science, Technology, Engineering and Mathematics in Asia

    Science.gov (United States)

    Salmon, Aliénor

    2015-01-01

    What factors might be causing the low participation of women Science, Technology, Engineering and Mathematics (STEM) fields? What can be done to attract more girls and women into STEM in Asia and beyond? The report, "A Complex Formula. Girls and Women in Science, Technology, Engineering and Mathematics in Asia", answers three fundamental…

  20. A Complex Formula: Girls and Women in Science, Technology, Engineering and Mathematics in Asia

    Science.gov (United States)

    Salmon, Aliénor

    2015-01-01

    What factors might be causing the low participation of women Science, Technology, Engineering and Mathematics (STEM) fields? What can be done to attract more girls and women into STEM in Asia and beyond? The report, "A Complex Formula. Girls and Women in Science, Technology, Engineering and Mathematics in Asia", answers three fundamental…

  1. Porous silicon-based scaffolds for tissue engineering and other biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Coffer, Jeffery L.; Whitehead, Melanie A.; Nagesha, Dattatri K.; Mukherjee, Priyabrata [Department of Chemistry, Texas Christian University, Ft. Worth, TX 76129 (United States); Akkaraju, Giridhar [Department of Biology, Texas Christian University, Ft. Worth, TX 76129 (United States); Totolici, Mihaela; Saffie, Roghieh S.; Canham, Leigh T. [PSi Medica Ltd. Malvern, Worcs (United Kingdom)

    2005-06-01

    This work describes the formation of porous composite materials based on a combination of bioactive mesoporous silicon and bioerodible polymers such as poly-caprolactone (PCL). The fabrication of a range of composites prepared by both salt leaching and microemulsion techniques are discussed. Particular attention to the influence of Si content in the composite on in vitro calcification assays are assessed. For each system, cytotoxicity and cellular proliferation are explicitly evaluated through fibroblast cell culture assays. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Chemical engineering of self-assembled Alzheimer's peptide on a silanized silicon surface.

    Science.gov (United States)

    Ammar, Mehdi; Smadja, Claire; Ly, Giang Thi Phuong; Tandjigora, Diénaba; Vigneron, Jackie; Etcheberry, Arnaud; Taverna, Myriam; Dufour-Gergam, Elisabeth

    2014-05-27

    The aim of this work is to develop a sensitive and specific immune-sensing platform dedicated to the detection of potential biomarkers of Alzheimer's disease (AD) in biological fluids. Accordingly, a controlled and adaptive surface functionalization of a silicon wafer with 7-octenyltrichlorosilane has been performed. The surface has extensively been characterized by atomic force microscopy (AFM; morphology) and X-ray photoelectron spectroscopy (XPS; chemical composition) and contact angle measurements. The wettability of the grafted chemical groups demonstrated the gradual trend from hydrophilic to hydrophobic surface during functionalization. XPS evidenced the presence of silanes on the surface after silanization, and even carboxylic groups as products from the oxidation step of the functionalization process. The characterization results permitted us to define an optimal protocol to reach a high-quality grafting yield. The issue of the quality of controlled chemical preparation on bioreceiving surfaces was also investigated by the recognition of one AD biomarker, the amyloid peptide Aβ 1-42. We have therefore evaluated the biological activity of the grafted anti Aβ antibodies onto this silanized surface by fluorescent microscopy. In conclusion, we have shown, both qualitatively and quantitatively, the uniformity of the optimized functionalization on slightly oxidized silicon surfaces, providing a reliable and chemically stable procedure to determine specific biomarkers of Alzheimer disease. This work opens the route to the integration of controlled immune-sensing applications on lab-on-chip systems.

  3. Time domain simulation of tandem silicon solar cells with optimal textured light trapping enabled by the quadratic complex rational function.

    Science.gov (United States)

    Chung, H; Jung, K-Y; Tee, X T; Bermel, P

    2014-05-05

    Amorphous silicon/crystalline silicon (a-Si/c-Si) micromorph tandem cells, with best confirmed efficiency of 12.3%, have yet to fully approach their theoretical performance limits. In this work, we consider a strategy for improving the light trapping and charge collection of a-Si/c-Si micromorph tandem cells using random texturing with adjustable short-range correlations and long-range periodicity. In order to consider the full-spectrum absorption of a-Si and c-Si, a novel dispersion model known as a quadratic complex rational function (QCRF) is applied to photovoltaic materials (e.g., a-Si, c-Si and silver). It has the advantage of accurately modeling experimental semiconductor dielectric values over the entire relevant solar bandwidth from 300-1000 nm in a single simulation. This wide-band dispersion model is then used to model a silicon tandem cell stack (ITO/a-Si:H/c-Si:H/silver), as two parameters are varied: maximum texturing height h and correlation parameter f. Even without any other light trapping methods, our front texturing method demonstrates 12.37% stabilized cell efficiency and 12.79 mA/cm² in a 2 μm-thick active layer.

  4. Multipoint alignment monitoring with amorphous silicon position detectors in a complex light path

    Energy Technology Data Exchange (ETDEWEB)

    Alberdi, J.; Arce, P.; Barcala, J.M.; Calvo, E. [CIEMAT, Madrid (Spain); Ferrando, A., E-mail: antonio.ferrando@ciemat.e [CIEMAT, Madrid (Spain); Josa, M.I.; Molinero, A.; Navarrete, J.; Oller, J.C.; Yuste, C. [CIEMAT, Madrid (Spain); Calderon, A.; Gomez, G.; Gonzalez-Sanchez, F.J.; Martinez-Rivero, C.; Matorras, F.; Rodrigo, T.; Ruiz-Arbol, P.; Sobron, M.; Vila, I.; Virto, A.L. [Instituto de Fisica de Cantabria. CSIC-University of Cantabria, Santander (Spain)

    2010-12-01

    This document presents an application of the new generation of amorphous silicon position detecting (ASPD) sensors to multipoint alignment. Twelve units are monitored along a 20 m long laser beam, where the light path is deflected by 90{sup o} using a pentaprism.

  5. Silicon solar cells reaching the efficiency limits: from simple to complex modelling

    Science.gov (United States)

    Kowalczewski, Piotr; Redorici, Lisa; Bozzola, Angelo; Andreani, Lucio Claudio

    2016-05-01

    Numerical modelling is pivotal in the development of high efficiency solar cells. In this contribution we present different approaches to model the solar cell performance: the diode equation, a generalization of the well-known Hovel model, and a complete device modelling. In all three approaches we implement a Lambertian light trapping, which is often considered as a benchmark for the optical design of solar cells. We quantify the range of parameters for which all three approaches give the same results, and highlight the advantages and limitations of different models. Using these methods we calculate the efficiency limits of single-junction crystalline silicon solar cells in a wide range of cell thickness. We find that silicon solar cells close to the efficiency limits operate in the high-injection (rather than in the low-injection) regime. In such a regime, surface recombination can have an unexpectedly large effect on cells with the absorber thickness lower than a few tens of microns. Finally, we calculate the limiting efficiency of tandem silicon-perovskite solar cells, and we determine the optimal thickness of the bottom silicon cell for different band gaps of the perovskite material.

  6. The Complex Dynamics of Student Engagement in Novel Engineering Design Activities

    Science.gov (United States)

    McCormick, Mary

    In engineering design, making sense of "messy," design situations is at the heart of the discipline (Schon, 1983); engineers in practice bring structure to design situations by organizing, negotiating, and coordinating multiple aspects (Bucciarelli, 1994; Stevens, Johri, & O'Connor, 2014). In classroom settings, however, students are more often given well-defined, content-focused engineering tasks (Jonassen, 2014). These tasks are based on the assumption that elementary students are unable to grapple with the complexity or open-endedness of engineering design (Crismond & Adams, 2012). The data I present in this dissertation suggest the opposite. I show that students are not only able to make sense of, or frame (Goffman, 1974), complex design situations, but that their framings dynamically involve their nascent abilities for engineering design. The context of this work is Novel Engineering, a larger research project that explores using children's literature as an access point for engineering design. Novel Engineering activities are inherently messy: there are characters with needs, settings with implicit constraints, and rich design situations. In a series of three studies, I show how students' framings of Novel Engineering design activities involve their reasoning and acting as beginning engineers. In the first study, I show two students whose caring for the story characters contributes to their stability in framing the task: they identify the needs of their fictional clients and iteratively design a solution to meet their clients' needs. In the second, I show how students' shifting and negotiating framings influence their engineering assumptions and evaluation criteria. In the third, I show how students' coordinating framings involve navigating a design process to meet clients' needs, classroom expectations, and technical requirements. Collectively, these studies contribute to literature by documenting students' productive beginnings in engineering design. The

  7. Engineering complex tissue-like microgel arrays for evaluating stem cell differentiation

    DEFF Research Database (Denmark)

    Guermani, Enrico; Shaki, Hossein; Mohanty, Soumyaranjan

    2016-01-01

    spreading and osteogenic differentiation of human mesenchymal stem cells (hMSCs) into complex tissue-like structures. In summary, we have developed a tissue-like microgel array for evaluating stem cell differentiation within complex and heterogeneous cell microenvironments. We anticipate that the developed......Development of tissue engineering scaffolds with native-like biology and microarchitectures is a prerequisite for stem cell mediated generation of off-the-shelf-tissues. So far, the field of tissue engineering has not full-filled its grand potential of engineering such combinatorial scaffolds...... for engineering functional tissues. This is primarily due to the many challenges associated with finding the right microarchitectures and ECM compositions for optimal tissue regeneration. Here, we have developed a new microgel array to address this grand challenge through robotic printing of complex stem cell...

  8. The Search Engine for Multi-Proteoform Complexes: An Online Tool for the Identification and Stoichiometry Determination of Protein Complexes.

    Science.gov (United States)

    Skinner, Owen S; Schachner, Luis F; Kelleher, Neil L

    2016-12-08

    Recent advances in top-down mass spectrometry using native electrospray now enable the analysis of intact protein complexes with relatively small sample amounts in an untargeted mode. Here, we describe how to characterize both homo- and heteropolymeric complexes with high molecular specificity using input data produced by tandem mass spectrometry of whole protein assemblies. The tool described is a "search engine for multi-proteoform complexes," (SEMPC) and is available for free online. The output is a list of candidate multi-proteoform complexes and scoring metrics, which are used to define a distinct set of one or more unique protein subunits, their overall stoichiometry in the intact complex, and their pre- and post-translational modifications. Thus, we present an approach for the identification and characterization of intact protein complexes from native mass spectrometry data. © 2016 by John Wiley & Sons, Inc.

  9. Cooling phonons with phonons: Acoustic reservoir engineering with silicon-vacancy centers in diamond

    Science.gov (United States)

    Kepesidis, K. V.; Lemonde, M.-A.; Norambuena, A.; Maze, J. R.; Rabl, P.

    2016-12-01

    We study a setup where a single negatively-charged silicon-vacancy center in diamond is magnetically coupled to a low-frequency mechanical bending mode and via strain to the high-frequency phonon continuum of a semiclamped diamond beam. We show that under appropriate microwave driving conditions, this setup can be used to induce a laser-cooling-like effect for the low-frequency mechanical vibrations, where the high-frequency longitudinal compression modes of the beam serve as an intrinsic low-temperature reservoir. We evaluate the experimental conditions under which cooling close to the quantum ground state can be achieved and describe an extended scheme for the preparation of a stationary entangled state between two mechanical modes. By relying on intrinsic properties of the mechanical beam only, this approach offers an interesting alternative for quantum manipulation schemes of mechanical systems, where otherwise efficient optomechanical interactions are not available.

  10. Information Flow Through Stages of Complex Engineering Design Projects: A Dynamic Network Analysis Approach

    DEFF Research Database (Denmark)

    Parraguez, Pedro; Eppinger, Steven D.; Maier, Anja

    2015-01-01

    information flows between activities in complex engineering design projects; 2) we show how the network of information flows in a large-scale engineering project evolved over time and how network analysis yields several managerial insights; and 3) we provide a useful new representation of the engineering...... design process and thus support theory-building toward the evolution of information flows through systems engineering stages. Implications include guidance on how to analyze and predict information flows as well as better planning of information flows in engineering design projects according......The pattern of information flow through the network of interdependent design activities is thought to be an important determinant of engineering design process results. A previously unexplored aspect of such patterns relates to the temporal dynamics of information transfer between activities...

  11. Repair of acutely injured spinal cord through constructing tissue-engineered neural complex in adult rats

    Institute of Scientific and Technical Information of China (English)

    PU Yu; GUO Qing-shan; WANG Ai-min; WU Si-yu; XING Shu-xing; ZHANG Zhong-rong

    2007-01-01

    Objective: To construct tissue-engineered neural complex in vitro and study its effect in repairing acutely injured spinal cord in adult rats. Methods: Neural stem cells were harvested from the spinal cord of embryo rats and propagated in vitro. Then the neural stem cells were seeded into polyglycolic acid scaffolds and co-cultured with extract of embryonic spinal cord in vitro. Immunofluorescence histochemistry and scanning electron microscope were used to observe the microstructure of this complex. Animal model of spine semi-transection was made and tissue-engineered neural complex was implanted by surgical intervention. Six weeks after transplantation, functional evaluation and histochemistry were applied to evaluate the functional recovery and anatomic reconstruction. Results: The tissue-engineered neural complex had a distinct structure, which contained neonatal neurons, oligodendrocytes and astrocytes. After tissue-engineered neural complex was implanted into the injured spinal cord, the cell components such as neurons, astrocytes and oligodendrocytes, could survive and keep on developing. The adult rats suffering from spinal cord injury got an obvious neurological recovery in motor skills. Conclusions: The tissue-engineered neural complex appears to have therapeutic effects on the functional recovery and anatomic reconstruction of the adult rats with spinal cord injury.

  12. Applying cognitive system engineering to cope with complexity in enterprises

    CSIR Research Space (South Africa)

    Oosthuizen, R

    2012-08-01

    Full Text Available have the cognitive ability to develop creative solutions as required within the complex environment. The Human Machine Interfaces (HMI) between the humans and the enterprise Command and Control system must be geared to support and enhance the human...

  13. Can Complexity Science Support the Engineering of Critical Network Infrastructures?

    Science.gov (United States)

    2007-10-01

    New York City, published an article in American Scientist titled “Science and Complexity” [2]. In this article, he contrasted three classes of problems...Science and complexity,” American Scientist , vol. 36, pp. 536–544, 1948. [3] P. Bak, How nature works: the science of self-organized criticality

  14. Engineering Complex Human-Technological Work Systems: A Sensemaking Approach

    Science.gov (United States)

    2007-06-01

    by Rene Descartes , Immanuel Kant, and Ludwig Wittgenstein, and mathematically by Alfred North Whitehead and Bertrand Russell. Logical rationalism...reductionism—originally introduced by Descartes in 1673)— asserts that complex objects, phenomena, theories, and meanings can always be reduced to a...Positivism Essentialism Analytic Philosophy Social Constructivism Nominalism Autopoiesis Descartes Plato Aristotle Aquinas Bacon Locke Wittgenstein

  15. Structural and Topology Optimization of Complex Civil Engineering Structures

    DEFF Research Database (Denmark)

    Hald, Frederik; Kirkegaard, Poul Henning; Andersen, Lars Vabbersgaard

    2013-01-01

    will be optimized using the commercial code Abaqus CAE. The structures are: a bucket foundation for an off-shore submarine structure for a wind turbine, and a pedestrian footbridge over a freeway. The topology optimization method used is the SIMP method, based on minimizing the structures' compliance. Complex load...

  16. The role of point defects and defect complexes in silicon device processing. Summary report and papers

    Energy Technology Data Exchange (ETDEWEB)

    Sopori, B.; Tan, T.Y.

    1994-08-01

    This report is a summary of a workshop hold on August 24--26, 1992. Session 1 of the conference discussed characteristics of various commercial photovoltaic silicon substrates, the nature of impurities and defects in them, and how they are related to the material growth. Session 2 on point defects reviewed the capabilities of theoretical approaches to determine equilibrium structure of defects in the silicon lattice arising from transitional metal impurities and hydrogen. Session 3 was devoted to a discussion of the surface photovoltaic method for characterizing bulk wafer lifetimes, and to detailed studies on the effectiveness of various gettering operations on reducing the deleterious effects of transition metals. Papers presented at the conference are also included in this summary report.

  17. Band engineering of amorphous silicon ruthenium thin film and its near-infrared absorption enhancement combined with nano-holes pattern on back surface of silicon substrate

    Science.gov (United States)

    Guo, Anran; Zhong, Hao; Li, Wei; Gu, Deen; Jiang, Xiangdong; Jiang, Yadong

    2016-10-01

    Silicon is widely used in semiconductor industry but has poor performance in near-infrared photoelectronic devices because of its bandgap limit. In this study, a narrow bandgap silicon rich semiconductor is achieved by introducing ruthenium (Ru) into amorphous silicon (a-Si) to form amorphous silicon ruthenium (a-Si1-xRux) thin films through co-sputtering. The increase of Ru concentration leads to an enhancement of light absorption and a narrower bandgap. Meanwhile, a specific light trapping technique is employed to realize high absorption of a-Si1-xRux thin film in a finite thickness to avoid unnecessary carrier recombination. A double-layer absorber comprising of a-Si1-xRux thin film and silicon random nano-holes layer is formed on the back surface of silicon substrates, and significantly improves near-infrared absorption while the leaky light intensity is less than 5%. This novel absorber, combining narrow bandgap thin film with light trapping structure, may have a potential application in near-infrared photoelectronic devices.

  18. Engineering Complex Embedded Systems with State Analysis and the Mission Data System

    Science.gov (United States)

    Ingham, Michel D.; Rasmussen, Robert D.; Bennett, Matthew B.; Moncada, Alex C.

    2004-01-01

    It has become clear that spacecraft system complexity is reaching a threshold where customary methods of control are no longer affordable or sufficiently reliable. At the heart of this problem are the conventional approaches to systems and software engineering based on subsystem-level functional decomposition, which fail to scale in the tangled web of interactions typically encountered in complex spacecraft designs. Furthermore, there is a fundamental gap between the requirements on software specified by systems engineers and the implementation of these requirements by software engineers. Software engineers must perform the translation of requirements into software code, hoping to accurately capture the systems engineer's understanding of the system behavior, which is not always explicitly specified. This gap opens up the possibility for misinterpretation of the systems engineer s intent, potentially leading to software errors. This problem is addressed by a systems engineering methodology called State Analysis, which provides a process for capturing system and software requirements in the form of explicit models. This paper describes how requirements for complex aerospace systems can be developed using State Analysis and how these requirements inform the design of the system software, using representative spacecraft examples.

  19. HISTOLOGICAL ANALYSIS OF IN VITRO REGENERATION OF HUMAN DENTAL PULP COMPLEX WITH AUTOLOGOUS TISSULAR ENGINEERING

    OpenAIRE

    Romero Márquez, Ricardo Manuel; Docente Colaborador del Departamento de Ciencias Básicas Estomatológicas, Curso de Patología General y del Sistema Estomatognático. Facultad de Odontología. UNMSM.

    2014-01-01

    A long time ago, dental pulp-complex regeneration was our main objective in radicular reparation which could guarantee all appropiate growth of healthy and functional tissue. The present study is about a histological assay of a new dentinal-pulp complex formation using platelet rich plasm, pulpar tissue and fibrina, all autolougus, as components of dental pulp tissular engineering treatment. Qualitative and quantitative assays about the dentin pulp-complex regeneration grade on experimental a...

  20. Systems Engineering Metrics: Organizational Complexity and Product Quality Modeling

    Science.gov (United States)

    Mog, Robert A.

    1997-01-01

    Innovative organizational complexity and product quality models applicable to performance metrics for NASA-MSFC's Systems Analysis and Integration Laboratory (SAIL) missions and objectives are presented. An intensive research effort focuses on the synergistic combination of stochastic process modeling, nodal and spatial decomposition techniques, organizational and computational complexity, systems science and metrics, chaos, and proprietary statistical tools for accelerated risk assessment. This is followed by the development of a preliminary model, which is uniquely applicable and robust for quantitative purposes. Exercise of the preliminary model using a generic system hierarchy and the AXAF-I architectural hierarchy is provided. The Kendall test for positive dependence provides an initial verification and validation of the model. Finally, the research and development of the innovation is revisited, prior to peer review. This research and development effort results in near-term, measurable SAIL organizational and product quality methodologies, enhanced organizational risk assessment and evolutionary modeling results, and 91 improved statistical quantification of SAIL productivity interests.

  1. Consolidation of silicon nitride without additives. [for gas turbine engine efficiency increase

    Science.gov (United States)

    Sikora, P. F.; Yeh, H. C.

    1976-01-01

    The use of ceramics for gas turbine engine construction might make it possible to increase engine efficiency by raising operational temperatures to values beyond those which can be tolerated by metallic alloys. The most promising ceramics being investigated in this connection are Si3N4 and SiC. A description is presented of a study which had the objective to produce dense Si3N4. The two most common methods of consolidating Si3N4 currently being used include hot pressing and reaction sintering. The feasibility was explored of producing a sound, dense Si3N4 body without additives by means of conventional gas hot isostatic pressing techniques and an uncommon hydraulic hot isostatic pressing technique. It was found that Si3N4 can be densified without additions to a density which exceeds 95% of the theoretical value

  2. Engineering and Optimization of Silicon-Iron-Manganese Nanoalloy Electrode for Enhanced Lithium-Ion Battery

    Science.gov (United States)

    Alaboina, Pankaj K.; Cho, Jong-Soo; Cho, Sung-Jin

    2017-10-01

    The electrochemical performance of a battery is considered to be primarily dependent on the electrode material. However, engineering and optimization of electrodes also play a crucial role, and the same electrode material can be designed to offer significantly improved batteries. In this work, Si-Fe-Mn nanomaterial alloy (Si/alloy) and graphite composite electrodes were densified at different calendering conditions of 3, 5, and 8 tons, and its influence on electrode porosity, electrolyte wettability, and long-term cycling was investigated. The active material loading was maintained very high ( 2 mg cm-2) to implement electrode engineering close to commercial loading scales. The densification was optimized to balance between the electrode thickness and wettability to enable the best electrochemical properties of the Si/alloy anodes. In this case, engineering and optimizing the Si/alloy composite electrodes to 3 ton calendering (electrode densification from 0.39 to 0.48 g cm-3) showed enhanced cycling stability with a high capacity retention of 100% over 100 cycles. [Figure not available: see fulltext.

  3. Stress engineering with silicon nitride stressors for Ge-on-Si lasers

    CERN Document Server

    Ke, Jiaxin; Guangrui,; Xia,

    2016-01-01

    Side and top silicon nitride stressors were proposed and shown to be effective ways to reduce the threshold current Ith and improve the wall-plug efficiency {\\eta}wp of Ge-on-Si lasers. Side stressors only turned out to be a more efficient way to increase {\\eta}wp than using top and side stressors together. With the side stressors only and geometry optimizations, a {\\eta}wp of 30.5% and an Ith of 50 mA (Jth of 37 kA/cm2) can be achieved with the defect limited carrier lifetime of 1 nsec. With the defect limited carrier lifetime of 10 nsec, an Ith of 7.8 mA (Jth of 5.8 kA/cm2) and a wall-plug efficiency of 38.7% can be achieved. These are tremendous improvements from the case without any stressors. These results give strong support to the Ge-on-Si laser technology and provide an effective way to improve the Ge laser performance.

  4. Patterning human neuronal networks on photolithographically engineered silicon dioxide substrates functionalized with glial analogues.

    Science.gov (United States)

    Hughes, Mark A; Brennan, Paul M; Bunting, Andrew S; Cameron, Katherine; Murray, Alan F; Shipston, Mike J

    2014-05-01

    Interfacing neurons with silicon semiconductors is a challenge being tackled through various bioengineering approaches. Such constructs inform our understanding of neuronal coding and learning and ultimately guide us toward creating intelligent neuroprostheses. A fundamental prerequisite is to dictate the spatial organization of neuronal cells. We sought to pattern neurons using photolithographically defined arrays of polymer parylene-C, activated with fetal calf serum. We used a purified human neuronal cell line [Lund human mesencephalic (LUHMES)] to establish whether neurons remain viable when isolated on-chip or whether they require a supporting cell substrate. When cultured in isolation, LUHMES neurons failed to pattern and did not show any morphological signs of differentiation. We therefore sought a cell type with which to prepattern parylene regions, hypothesizing that this cellular template would enable secondary neuronal adhesion and network formation. From a range of cell lines tested, human embryonal kidney (HEK) 293 cells patterned with highest accuracy. LUHMES neurons adhered to pre-established HEK 293 cell clusters and this coculture environment promoted morphological differentiation of neurons. Neurites extended between islands of adherent cell somata, creating an orthogonally arranged neuronal network. HEK 293 cells appear to fulfill a role analogous to glia, dictating cell adhesion, and generating an environment conducive to neuronal survival. We next replaced HEK 293 cells with slower growing glioma-derived precursors. These primary human cells patterned accurately on parylene and provided a similarly effective scaffold for neuronal adhesion. These findings advance the use of this microfabrication-compatible platform for neuronal patterning.

  5. A silicon tracker for Christmas

    CERN Multimedia

    2008-01-01

    The CMS experiment installed the world’s largest silicon tracker just before Christmas. Marcello Mannelli: physicist and deputy CMS project leader, and Alan Honma, physicist, compare two generations of tracker: OPAL for the LEP (at the front) and CMS for the LHC (behind). There is quite a difference between 1m2 and 205m2.. CMS received an early Christmas present on 18 December when the silicon tracker was installed in the heart of the CMS magnet. The CMS tracker team couldn’t have hoped for a better present. Carefully wrapped in shiny plastic, the world’s largest silicon tracker arrived at Cessy ready for installation inside the CMS magnet on 18 December. This rounded off the year for CMS with a major event, the crowning touch to ten years of work on the project by over five hundred scientists and engineers. "Building a scientific instrument of this size and complexity is a huge technical a...

  6. Reconfiguring The Supply Chain For Complex Engineered Products

    DEFF Research Database (Denmark)

    Wæhrens, Brian Vejrum; Asmussen, Jesper Normann

    2016-01-01

    Supply chains are faced by increasingly challenging requirements, exemplified by shorter time to market, cost pressure, increased variance and quality requirements This poses a number of challenges to the overall demand for SC management to ensure a systematic fit between the configuration...... of the SC, the product and market requirements. This paper seeks to investigate the factors which create a need for supply chain reconfiguration in the context of the Complex Product Systems, together with the enablers and barriers for successfully realizing supply chain improvements through reconfiguration....

  7. Features Performance Indicators and Quality Engineering and Maintenance and Cold Storage Complex

    Directory of Open Access Journals (Sweden)

    Dyakova Yu. A.

    2013-01-01

    Full Text Available The article discusses the features of efficiency and quality indicators of engineering and technical maintenance of storage and refrigeration facilities. The concept of engineering and maintenance of such systems is explained; it includes design, installation and commissioning of refrigeration, ventilation and air-conditioning, as well as warranty, post-warranty, preventative and advisory services. General definition of the quality index applied to the quality of the service process and definition of the complex index of the quality of services are clarified. Individual indicators of quality engineering and technical services are described. The article defines the dependence of integral complex index of quality, efficiency, maintenance costs on specific parties to a contract for the provision of engineering and technical services. The concept of weighting factors of such costs are introduced.

  8. Engineering the anthocyanin regulatory complex of strawberry (Fragaria vesca

    Directory of Open Access Journals (Sweden)

    Kui eLin-Wang

    2014-11-01

    Full Text Available The woodland strawberry, Fragaria vesca is a model fruit for a number of rosaceous crops. We have engineered altered concentrations of anthocyanin in F. vesca, to determine the impact on plant growth and fruit quality. Anthocyanin concentrations were significantly increased by over-expression or decreased by knock-down of the R2R3 MYB activator, MYB10. In contrast, a potential bHLH partner for MYB10 (bHLH33 did not affect the anthocyanin pathway when knocked down using RNAi constructs. Metabolic analysis of fruits revealed that, of all the polyphenolics surveyed, only cyanidin and pelargonidin glucoside, and coumaryl hexose were significantly affected by over-expression and knock down of MYB10. Using the F. vesca genome sequence, members of the MYB, bHLH and WD40 families were examined. Global analysis of gene expression and targeted qPCR analysis of biosynthetic genes and regulators confirmed the effects of altering MYB10 expression, as well as the knock-down of bHLH33. Other members of the MYB transcription factor family were affected by the transgenes. Transient expression of strawberry genes in Nicotiana benthamiana revealed that MYB10 can auto-regulate itself, and potential repressors of MYB10. In tobacco, MYB10’s activation of biosynthetic steps is inhibited by the strawberry repressor MYB1.

  9. Complex 3D Vortex Lattice Formation by Phase-Engineered Multiple Beam Interference

    Directory of Open Access Journals (Sweden)

    Jolly Xavier

    2012-01-01

    Full Text Available We present the computational results on the formation of diverse complex 3D vortex lattices by a designed superposition of multiple plane waves. Special combinations of multiples of three noncoplanar plane waves with a designed relative phase shift between one another are perturbed by a nonsingular beam to generate various complex 3D vortex lattice structures. The formation of complex gyrating lattice structures carrying designed vortices by means of relatively phase-engineered plane waves is also computationally investigated. The generated structures are configured with both periodic as well as transversely quasicrystallographic basis, while these whirling complex lattices possess a long-range order of designed symmetry in a given plane. Various computational analytical tools are used to verify the presence of engineered geometry of vortices in these complex 3D vortex lattices.

  10. Organizational Influences on Interdisciplinary Interactions during Research and Design of Large-Scale Complex Engineered Systems

    Science.gov (United States)

    McGowan, Anna-Maria R.; Seifert, Colleen M.; Papalambros, Panos Y.

    2012-01-01

    The design of large-scale complex engineered systems (LaCES) such as an aircraft is inherently interdisciplinary. Multiple engineering disciplines, drawing from a team of hundreds to thousands of engineers and scientists, are woven together throughout the research, development, and systems engineering processes to realize one system. Though research and development (R&D) is typically focused in single disciplines, the interdependencies involved in LaCES require interdisciplinary R&D efforts. This study investigates the interdisciplinary interactions that take place during the R&D and early conceptual design phases in the design of LaCES. Our theoretical framework is informed by both engineering practices and social science research on complex organizations. This paper provides preliminary perspective on some of the organizational influences on interdisciplinary interactions based on organization theory (specifically sensemaking), data from a survey of LaCES experts, and the authors experience in the research and design. The analysis reveals couplings between the engineered system and the organization that creates it. Survey respondents noted the importance of interdisciplinary interactions and their significant benefit to the engineered system, such as innovation and problem mitigation. Substantial obstacles to interdisciplinarity are uncovered beyond engineering that include communication and organizational challenges. Addressing these challenges may ultimately foster greater efficiencies in the design and development of LaCES and improved system performance by assisting with the collective integration of interdependent knowledge bases early in the R&D effort. This research suggests that organizational and human dynamics heavily influence and even constrain the engineering effort for large-scale complex systems.

  11. Socio-Technical Perspective on Interdisciplinary Interactions During the Development of Complex Engineered Systems

    Science.gov (United States)

    McGowan, Anna-Maria R.; Daly, Shanna; Baker, Wayne; Papalambros, panos; Seifert, Colleen

    2013-01-01

    This study investigates interdisciplinary interactions that take place during the research, development, and early conceptual design phases in the design of large-scale complex engineered systems (LaCES) such as aerospace vehicles. These interactions, that take place throughout a large engineering development organization, become the initial conditions of the systems engineering process that ultimately leads to the development of a viable system. This paper summarizes some of the challenges and opportunities regarding social and organizational issues that emerged from a qualitative study using ethnographic and survey data. The analysis reveals several socio-technical couplings between the engineered system and the organization that creates it. Survey respondents noted the importance of interdisciplinary interactions and their benefits to the engineered system as well as substantial challenges in interdisciplinary interactions. Noted benefits included enhanced knowledge and problem mitigation and noted obstacles centered on organizational and human dynamics. Findings suggest that addressing the social challenges may be a critical need in enabling interdisciplinary interactions

  12. A solution of multidisciplinary collaborative simulation for complex engineering systems in a distributed heterogeneous environment

    Institute of Scientific and Technical Information of China (English)

    ZHANG HeMing

    2009-01-01

    This paper presents an integrated approach to multidisciplinary collaborative simulation for complex engineering systems. The formulized paradigm of mulUdisciplinary collaborative simulation for com-plex engineering systems is principally analyzed. An IEEE HLA and web services based framework is proposed to provide a heterogeneous, distributed and collaborative running environment where multi-disciplinary modeling, running management and post-processing of collaborative simulation are under-taken. The mechanism of multidisciplinary collaborative modeling, disciplinary model transformation, and time-synchronized simulation advancement are studied in detail. A prototype with the functions of multidisciplinary modeling, running management and post-processing for collaborative simulations is developed, and a typical complex engineering system is chosen as a case study to demonstrate the effectiveness of this new approach towards collaborative simulation.

  13. Engineering Evaluation/Cost Analysis for Decommissioning of the Engineering Test Reactor Complex

    Energy Technology Data Exchange (ETDEWEB)

    A. B. Culp

    2006-10-01

    Preparation of this Engineering Evaluation/Cost Analysis is consistent with the joint U.S. Department of Energy and U.S. Environmental Protection Agency Policy on Decommissioning of Department of Energy Facilities Under the Comprehensive Environmental Response, Compensation, and Liability Act, which establishes the Comprehensive Environmental Response, Compensation, and Liability Act non-time-critical removal action (NTCRA) process as an approach for decommissioning.

  14. The engineering design integration (EDIN) system. [digital computer program complex

    Science.gov (United States)

    Glatt, C. R.; Hirsch, G. N.; Alford, G. E.; Colquitt, W. N.; Reiners, S. J.

    1974-01-01

    A digital computer program complex for the evaluation of aerospace vehicle preliminary designs is described. The system consists of a Univac 1100 series computer and peripherals using the Exec 8 operating system, a set of demand access terminals of the alphanumeric and graphics types, and a library of independent computer programs. Modification of the partial run streams, data base maintenance and construction, and control of program sequencing are provided by a data manipulation program called the DLG processor. The executive control of library program execution is performed by the Univac Exec 8 operating system through a user established run stream. A combination of demand and batch operations is employed in the evaluation of preliminary designs. Applications accomplished with the EDIN system are described.

  15. Integrated lithography to produce complex structures for spectral engineering

    CERN Document Server

    Csete, Maria; Szalai, Aniko; Szabo, Gabor

    2011-01-01

    An integrated interference and colloid sphere lithography (IICL) method is presented capable of producing complex plasmonic structures consisting of wavelength-scaled periodic arrays of nano-objects with arbitrary array symmetry and controllable nano-scaled sub-structures. The IICL method is based on illumination of colloid sphere monolayers by interference patterns synchronized with sphere arrays along arbitrary crystallographic directions. This nano-kaleidoscope method enables to tune four structure parameters independently: the symmetry and characteristic periodicity of the interference pattern might be varied by the wavelength, number and angle of incidence of the interfering beams; the colloid-spheres' diameter-scaled distance between the nano-objects is controllable by the relative orientation of the interference pattern with respect to the hexagonal lattice of colloid spheres; the size of the individual nano-objects is determined by the colloid-spheres diameter and by the illumination light wavelength ...

  16. Augmented cellular trafficking and endosomal escape of porous silicon nanoparticles via zwitterionic bilayer polymer surface engineering.

    Science.gov (United States)

    Shahbazi, Mohammad-Ali; Almeida, Patrick V; Mäkilä, Ermei M; Kaasalainen, Martti H; Salonen, Jarno J; Hirvonen, Jouni T; Santos, Hélder A

    2014-08-01

    The development of a stable vehicle with low toxicity, high cellular internalization, efficient endosomal escape, and optimal drug release profile is a key bottleneck in nanomedicine. To overcome all these problems, we have developed a successful layer-by-layer method to covalently conjugate polyethyleneimine (PEI) and poly(methyl vinyl ether-co-maleic acid) (PMVE-MA) copolymer on the surface of undecylenic acid functionalized thermally hydrocarbonized porous silicon nanoparticles (UnTHCPSi NPs), forming a bilayer zwitterionic nanocomposite containing free positive charge groups of hyper-branched PEI disguised by the PMVE-MA polymer. The surface smoothness, charge and hydrophilicity of the developed NPs considerably improved the colloidal and plasma stabilities via enhanced suspensibility and charge repulsion. Furthermore, despite the surface negative charge of the bilayer polymer-conjugated NPs, the cellular trafficking and endosomal escape were significantly increased in both MDA-MB-231 and MCF-7 breast cancer cells. Remarkably, we also showed that the conjugation of surface free amine groups of the highly toxic UnTHCPSi-PEI (Un-P) NPs to the carboxylic groups of PMVE-MA renders acceptable safety features to the system and preserves the endosomal escape properties via proton sponge mechanism of the free available amine groups located inside the hyper-branched PEI layer. Moreover, the double layer protection not only controlled the aggregation of the NPs and reduced the toxicity, but also sustained the drug release of an anticancer drug, methotrexate, with further improved cytotoxicity profile of the drug-loaded particles. These results provide a proof-of-concept evidence that such zwitterionic polymer-based PSi nanocomposites can be extensively used as a promising candidate for cytosolic drug delivery.

  17. A framework for feeding Linked Data to Complex Event Processing engines

    OpenAIRE

    2010-01-01

    A huge volume of Linked Data has been published on the Web, yet is not processable by Complex Event Processing (CEP) or Event Stream Processing (ESP) engines. This paper presents a frame-work to bridge this gap, under which Linked Data are first translated into events conforming to a lightweight ontology, and then fed to CEP engines. The event processing results will also be published back onto the Web of Data. In this way, CEP engines are connected to the Web of Data, and the ontological rea...

  18. Knowledge-driven approaches for engineering complex metabolic pathways in plants.

    Science.gov (United States)

    Farré, Gemma; Twyman, Richard M; Christou, Paul; Capell, Teresa; Zhu, Changfu

    2015-04-01

    Plant metabolic pathways are complex and often feature multiple levels of regulation. Until recently, metabolic engineering in plants relied on the laborious testing of ad hoc modifications to achieve desirable changes in the metabolic profile. However, technological advances in data mining, modeling, multigene engineering and genome editing are now taking away much of the guesswork by allowing the impact of modifications to be predicted more accurately. In this review we discuss recent developments in knowledge-based metabolic engineering strategies, that is the gathering and mining of genomic, transcriptomic, proteomic and metabolomic data to generate models of metabolic pathways that help to define and refine optimal intervention strategies.

  19. Modeling complexity in engineered infrastructure system: Water distribution network as an example

    Science.gov (United States)

    Zeng, Fang; Li, Xiang; Li, Ke

    2017-02-01

    The complex topology and adaptive behavior of infrastructure systems are driven by both self-organization of the demand and rigid engineering solutions. Therefore, engineering complex systems requires a method balancing holism and reductionism. To model the growth of water distribution networks, a complex network model was developed following the combination of local optimization rules and engineering considerations. The demand node generation is dynamic and follows the scaling law of urban growth. The proposed model can generate a water distribution network (WDN) similar to reported real-world WDNs on some structural properties. Comparison with different modeling approaches indicates that a realistic demand node distribution and co-evolvement of demand node and network are important for the simulation of real complex networks. The simulation results indicate that the efficiency of water distribution networks is exponentially affected by the urban growth pattern. On the contrary, the improvement of efficiency by engineering optimization is limited and relatively insignificant. The redundancy and robustness, on another aspect, can be significantly improved through engineering methods.

  20. Band engineering of amorphous silicon ruthenium thin film and its near-infrared absorption enhancement combined with nano-holes pattern on back surface of silicon substrate

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Anran; Zhong, Hao [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Li, Wei, E-mail: wli@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Gu, Deen; Jiang, Xiangdong [School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China); Jiang, Yadong [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2016-10-30

    Highlights: • The increase of Ru concentration leads to a narrower bandgap of a-Si{sub 1-x}Ru{sub x} thin film. • The absorption coefficient of a-Si{sub 1-x}Ru{sub x} is higher than that of SiGe. • A double-layer absorber comprising of a-Si{sub 1-x}Ru{sub x} film and Si nano-holes layer is achieved. - Abstract: Silicon is widely used in semiconductor industry but has poor performance in near-infrared photoelectronic devices because of its bandgap limit. In this study, a narrow bandgap silicon rich semiconductor is achieved by introducing ruthenium (Ru) into amorphous silicon (a-Si) to form amorphous silicon ruthenium (a-Si{sub 1-x}Ru{sub x}) thin films through co-sputtering. The increase of Ru concentration leads to an enhancement of light absorption and a narrower bandgap. Meanwhile, a specific light trapping technique is employed to realize high absorption of a-Si{sub 1-x}Ru{sub x} thin film in a finite thickness to avoid unnecessary carrier recombination. A double-layer absorber comprising of a-Si{sub 1-x}Ru{sub x} thin film and silicon random nano-holes layer is formed on the back surface of silicon substrates, and significantly improves near-infrared absorption while the leaky light intensity is less than 5%. This novel absorber, combining narrow bandgap thin film with light trapping structure, may have a potential application in near-infrared photoelectronic devices.

  1. Genetic Networks of Complex Disorders: from a Novel Search Engine for PubMed Article Database.

    Science.gov (United States)

    Jung, Jae-Yoon; Wall, Dennis Paul

    2013-01-01

    Finding genetic risk factors of complex disorders may involve reviewing hundreds of genes or thousands of research articles iteratively, but few tools have been available to facilitate this procedure. In this work, we built a novel publication search engine that can identify target-disorder specific, genetics-oriented research articles and extract the genes with significant results. Preliminary test results showed that the output of this engine has better coverage in terms of genes or publications, than other existing applications. We consider it as an essential tool for understanding genetic networks of complex disorders.

  2. Nanostructured silicon via metal assisted catalyzed etch (MACE): chemistry fundamentals and pattern engineering

    Science.gov (United States)

    Toor, Fatima; Miller, Jeffrey B.; Davidson, Lauren M.; Nichols, Logan; Duan, Wenqi; Jura, Michael P.; Yim, Joanne; Forziati, Joanne; Black, Marcie R.

    2016-10-01

    There are a range of different methods to generate a nanostructured surface on silicon (Si) but the most cost effective and optically interesting is the metal assisted wet chemical etching (MACE) (Koynov et al 2006 Appl. Phys. Lett. 88 203107). MACE of Si is a controllable, room-temperature wet-chemical technique that uses a thin layer of metal to etch the surface of Si, leaving behind various nano- and micro-scale surface features or ‘black silicon’. MACE-fabricated nanowires (NWs) provide improved antireflection and light trapping functionality (Toor et al 2016 Nanoscale 8 15448-66) compared with the traditional ‘iso-texturing’ (Campbell and Green 1987 J. Appl. Phys. 62 243-9). The resulting lower reflection and improved light trapping can lead to higher short circuit currents in NW solar cells (Toor et al 2011 Appl. Phys. Lett. 99 103501). In addition, NW cells can have higher fill factors and voltages than traditionally processed cells, thus leading to increased solar cell efficiencies (Cabrera et al 2013 IEEE J. Photovolt. 3 102-7). MACE NW processing also has synergy with next generation Si solar cell designs, such as thin epitaxial-Si and passivated emitter rear contact (Toor et al 2016 Nanoscale 8 15448-66). While several companies have begun manufacturing black Si, and many more are researching these techniques, much of the work has not been published in traditional journals and is publicly available only through conference proceedings and patent publications, which makes learning the field challenging. There have been three specialized review articles published recently on certain aspects of MACE or black Si, but do not present a full review that would benefit the industry (Liu et al 2014 Energy Environ. Sci. 7 3223-63 Yusufoglu et al 2015 IEEE J. Photovolt. 5 320-8 Huang et al 2011 Adv. Mater. 23 285-308). In this feature article, we review the chemistry of MACE and explore how changing parameters in the wet etch process effects the resulting

  3. EDUCATIONAL COMPLEX ON ELECTRICAL ENGINEERING AND ELECTRONICS BASED ON MODELING IN PROGRAM TINA

    Directory of Open Access Journals (Sweden)

    Vladimir A. Alekhin

    2014-01-01

    Full Text Available The educational complex on the electrical engineering and electronics has been developed. It contains a course of lectures and lecture notes in the electronic form, a new computer laboratory practical work and practical training. All electronic manuals are based on modeling of electric and electronic circuits in the new effective program TINA. The educational complex is being successfully used in educational process on internal and distant learning. 

  4. {Ni4O4} Cluster Complex to Enhance the Reductive Photocurrent Response on Silicon Nanowire Photocathodes

    Directory of Open Access Journals (Sweden)

    Yatin J. Mange

    2017-02-01

    Full Text Available Metal organic {Ni4O4} clusters, known oxidation catalysts, have been shown to provide a valuable route in increasing the photocurrent response on silicon nanowire (SiNW photocathodes. {Ni4O4} clusters have been paired with SiNWs to form a new photocathode composite for water splitting. Under AM1.5 conditions, the combination of {Ni4O4} clusters with SiNWs gave a current density of −16 mA/cm2, which corresponds to an increase in current density of 60% when compared to bare SiNWs. The composite electrode was fully characterised and shown to be an efficient and stable photocathode for water splitting.

  5. Computational study of interstitial oxygen and vacancy-oxygen complexes in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Pesola, M. [Laboratory of Physics, Helsinki University of Technology, P.O. Box 1100, FIN-02015 HUT (Finland); von Boehm, J. [LTAM, Helsinki University of Technology, P.O. Box 1100, FIN-02015 HUT (Finland); Mattila, T. [Laboratory of Physics, Helsinki University of Technology, P.O. Box 1100, FIN-02015 HUT (Finland)]|[National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Nieminen, R.M. [Laboratory of Physics, Helsinki University of Technology, P.O. Box 1100, FIN-02015 HUT (Finland)

    1999-10-01

    The formation and binding energies, the ionization levels, the structures, and the local vibrations of O{sub i}, O{sub 2i}, O{sub 3i}, VO, VO{sub 2}, and V{sub 2}O (V=vacancy) in silicon are calculated using a self-consistent total-energy pseudopotential method. The most important results are as follows: The ionization levels and associated structures are given for VO and V{sub 2}O as well as the local vibration modes for the negative charge states of VO. The experimental frequency of O{sub i} at 517 cm{sup {minus}1} is associated tentatively with an oxygen-induced silicon mode of weakly interacting O{sub i}{close_quote}s. We find two competing structures for O{sub 2i}: the staggered configuration and the skewed O{sub i}-Si-Si-O{sub i} configuration with the binding energies of 0.2 and 0.1 eV, respectively. The experimental frequencies of O{sub 2i} at 1060, 1012, 690, and 556 cm{sup {minus}1} are found to originate from the staggered O{sub 2i}. The experimental frequency of O{sub 2i} at 1105 cm{sup {minus}1} is found to originate from the skewed O{sub i}-Si-Si-O{sub i} configuration of O{sub 2i}. The calculated effects of pressure on the structures and local vibration frequencies (Gr{umlt u}neisen parameters) of O{sub i} and O{sub 2i} are presented. {copyright} {ital 1999} {ital The American Physical Society}

  6. Progressive design methodology for complex engineering systems based on multiobjective genetic algorithms and linguistic decision making

    NARCIS (Netherlands)

    Kumar, P.; Bauer, P.

    2008-01-01

    This work focuses on a design methodology that aids in design and development of complex engineering systems. This design methodology consists of simulation, optimization and decision making. Within this work a framework is presented in which modelling, multi-objective optimization and multi

  7. Progressive design methodology for complex engineering systems based on multiobjective genetic algorithms and linguistic decision making

    NARCIS (Netherlands)

    Kumar, P.; Bauer, P.

    2008-01-01

    This work focuses on a design methodology that aids in design and development of complex engineering systems. This design methodology consists of simulation, optimization and decision making. Within this work a framework is presented in which modelling, multi-objective optimization and multi criteri

  8. Engineering the Complex-Valued Constitutive Parameters of Metamaterials for Perfect Absorption.

    Science.gov (United States)

    Wang, Pengwei; Chen, Naibo; Tang, Chaojun; Chen, Jing; Liu, Fanxin; Sheng, Saiqian; Yan, Bo; Sui, Chenghua

    2017-12-01

    We theoretically studied how to directly engineer the constitutive parameters of metamaterials for perfect absorbers of electromagnetic waves. As an example, we numerically investigated the necessary refractive index n and extinction coefficient k and the relative permittivity ε and permeability μ of a metamaterial anti-reflection layer, which could cancel the reflection from a hydrogenated amorphous silicon (α-Si:H) thin film on a metal substrate, within the visible wavelength range from 300 to 800 nm. We found that the metamaterial anti-reflection layer should have a negative refractive index (n  0) for long-wavelength visible light. The relative permittivity ε and permeability μ could be fitted by the Lorentz model, which exhibited electric and magnetic resonances, respectively.

  9. Engineering the Complex-Valued Constitutive Parameters of Metamaterials for Perfect Absorption

    Science.gov (United States)

    Wang, Pengwei; Chen, Naibo; Tang, Chaojun; Chen, Jing; Liu, Fanxin; Sheng, Saiqian; Yan, Bo; Sui, Chenghua

    2017-04-01

    We theoretically studied how to directly engineer the constitutive parameters of metamaterials for perfect absorbers of electromagnetic waves. As an example, we numerically investigated the necessary refractive index n and extinction coefficient k and the relative permittivity ɛ and permeability μ of a metamaterial anti-reflection layer, which could cancel the reflection from a hydrogenated amorphous silicon (α-Si:H) thin film on a metal substrate, within the visible wavelength range from 300 to 800 nm. We found that the metamaterial anti-reflection layer should have a negative refractive index ( n 0) for long-wavelength visible light. The relative permittivity ɛ and permeability μ could be fitted by the Lorentz model, which exhibited electric and magnetic resonances, respectively.

  10. Engineering Life into Technology: the Application of Complexity Theory to a Potential Phase Transition in Intelligence

    Directory of Open Access Journals (Sweden)

    Melanie Swan

    2010-02-01

    Full Text Available Information optimization is a centerpiece phenomenon in the universe. It develops from simplicity, then continuously breaks symmetry and cycles through instability to progress to increasingly dense nodes of complexity and diversity. Intelligence has arisen as the information optimization node with the greatest complexity. A contemporary imbalance is presented in that exponentially growing technology could be poised as a potential sole successor to human intelligence. A complex dynamical system is emerging in response, the engineering of life into technology. Numerous network elements are developing which could self-organize into the next node of symmetry, a phase transition in intelligence.

  11. Work Function Adjustment by Using Dipole Engineering for TaN-Al2O3-Si3N4-HfSiOx-Silicon Nonvolatile Memory

    Directory of Open Access Journals (Sweden)

    Yu-Hsien Lin

    2015-08-01

    Full Text Available This paper presents a novel TaN-Al2O3-HfSiOx-SiO2-silicon (TAHOS nonvolatile memory (NVM design with dipole engineering at the HfSiOx/SiO2 interface. The threshold voltage shift achieved by using dipole engineering could enable work function adjustment for NVM devices. The dipole layer at the tunnel oxide–charge storage layer interface increases the programming speed and provides satisfactory retention. This NVM device has a high program/erase (P/E speed; a 2-V memory window can be achieved by applying 16 V for 10 μs. Regarding high-temperature retention characteristics, 62% of the initial memory window was maintained after 103 P/E-cycle stress in a 10-year simulation. This paper discusses the performance improvement enabled by using dipole layer engineering in the TAHOS NVM.

  12. Biomechanical properties of an implanted engineered tubular gut-sphincter complex.

    Science.gov (United States)

    Zakhem, Elie; El Bahrawy, Mostafa; Orlando, Giuseppe; Bitar, Khalil N

    2016-11-23

    Neuromuscular diseases of the gut alter the normal motility patterns. Although surgical intervention remains the standard treatment, preservation of the sphincter attached to the rest of the gut is challenging. The present study aimed to evaluate a bioengineered gut-sphincter complex following its subcutaneous implantation for 4 weeks in rats. Engineered innervated human smooth muscle sheets and innervated human sphincters with a predefined alignment were placed around tubular scaffolds to create a gut-sphincter complex. The engineered complex was subcutaneously implanted in the abdomen of the rats for 4 weeks. The implanted tissues were vascularized. In vivo manometry revealed luminal pressure at the gut and the sphincter zone. Tensile strength, elongation at break and Young's modulus of the engineered complexes were similar to those of native rat intestine. Histological and immunofluorescence assays showed maintenance of smooth muscle circular alignment in the engineered tissue, maintenance of smooth muscle contractile phenotype and innervation of the smooth muscle. Electrical field stimulation induced relaxation of the smooth muscle of both the sphincter and the gut parts. Relaxation was partly inhibited by nitric oxide inhibitor indicating nitrergic contribution to relaxation. The present study has demonstrated for the first time a successfully developed and subcutaneously implanted a tubular human-derived gut-sphincter complex. The sphincteric part of Tubular Gut-Sphincter Complex (TGSC) maintained the basal tone characteristic of a native sphincter. The gut part also maintained its specific neuromuscular characteristics. The results of this study provide a promising therapeutic approach to restore gut continuity and motility. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Data on biochemical fluxes generated from biofabricated enzyme complexes assembled through engineered tags and microbial transglutaminase

    Directory of Open Access Journals (Sweden)

    Narendranath Bhokisham

    2016-09-01

    Full Text Available Data presented is related to an article titled “Modular construction of multi-subunit protein complexes using engineered tags and microbial transglutaminase” (Bhokisham et al., 2016 [1]. In this article, we have presented western blot and flux data associated with assembly of Pfs–LuxS enzyme complexes on beads using uni-tagged and bi-tagged LuxS enzymes. We have also presented biochemical flux following changes in enzyme stoichiometries. We covalently coupled a Pfs-LuxS complex with Protein G, an antibody binding non-enzyme component and directed these complexes to the surfaces of bacterial cells via anti-Escherichia coli antibodies. Fluorescence microscopy images represented the altered behavior of bacterial cells in response to the autoinducer-2 that is synthesized by the Protein G-enzyme complexes.

  14. Ecological performance of a generalized irreversible Carnot heat engine with complex heat transfer law

    Directory of Open Access Journals (Sweden)

    Jun Li, Lingen Chen, Fengrui Sun

    2011-01-01

    Full Text Available The optimal ecological performance of a generalized irreversible Carnot heat engine with the losses of heat-resistance, heat leakage and internal irreversibility, in which the transfer between the working fluid and the heat reservoirs obeys a complex heat transfer law, including generalized convective heat transfer law and generalized radiative heat transfer law is derived by taking an ecological optimization criterion as the objective, which consists of maximizing a function representing the best compromise between the power and entropy production rate of the heat engine. The effects of heat transfer laws and various loss terms are analyzed. The obtained results include those obtained in many literatures.

  15. INTEGRATED SCIENTIFIC-MANUFACTURING COMPLEXES AS A BASIS OF MODERN MECHANICAL ENGINEERING

    Directory of Open Access Journals (Sweden)

    N.A. Malyh

    2007-03-01

    Full Text Available The experience of FGUP PO "Uralvagonzavod" development is shown in the article, the analysis of mechanical engineering development in our country on modern stage is given. The authors’ approach upon the possibility, necessity and inevitability of a single right perspective decision of such economical problem in short period by the native financial, scientific-technical and people resources of Russia is proven. The position of seeing defensive enterprises as modern integrated scientific-manufacturing complexes, which are a real basis for creation of qualitatively new technique and technology of mechanical engineering and other country’s industry sectors.

  16. Complexity

    CERN Document Server

    Gershenson, Carlos

    2011-01-01

    The term complexity derives etymologically from the Latin plexus, which means interwoven. Intuitively, this implies that something complex is composed by elements that are difficult to separate. This difficulty arises from the relevant interactions that take place between components. This lack of separability is at odds with the classical scientific method - which has been used since the times of Galileo, Newton, Descartes, and Laplace - and has also influenced philosophy and engineering. In recent decades, the scientific study of complexity and complex systems has proposed a paradigm shift in science and philosophy, proposing novel methods that take into account relevant interactions.

  17. Using social media to facilitate knowledge transfer in complex engineering environments: a primer for educators

    Science.gov (United States)

    Murphy, Glen; Salomone, Sonia

    2013-03-01

    While highly cohesive groups are potentially advantageous they are also often correlated with the emergence of knowledge and information silos based around those same functional or occupational clusters. Consequently, an essential challenge for engineering organisations wishing to overcome informational silos is to implement mechanisms that facilitate, encourage and sustain interactions between otherwise disconnected groups. This paper acts as a primer for those seeking to gain an understanding of the design, functionality and utility of a suite of software tools generically termed social media technologies in the context of optimising the management of tacit engineering knowledge. Underpinned by knowledge management theory and using detailed case examples, this paper explores how social media technologies achieve such goals, allowing for the transfer of knowledge by tapping into the tacit and explicit knowledge of disparate groups in complex engineering environments.

  18. Silicon Valley Ecosystem

    Institute of Scientific and Technical Information of China (English)

    Joseph Leu

    2005-01-01

    @@ It is unlikely that any industrial region of the world has received as much scrutiny and study as Silicon Valley. Despite the recent crash of Internet and telecommunications stocks,Silicon Valley remains the world's engine of growth for numerous high-technology sectors.

  19. Material and device engineering in fully depleted silicon-on-insulator transistors to realize a steep subthreshold swing using negative capacitance

    Science.gov (United States)

    Ota, Hiroyuki; Migita, Shinji; Hattori, Junichi; Fukuda, Koichi; Toriumi, Akira

    2016-08-01

    This paper discusses material and device engineering in field-effect transistors (FETs) with HfO2-based ferroelectric gate insulators to attain a precipitous subthreshold swing (SS) by exploiting negative capacitance. Our physical analysis based on a new concept of a negative dielectric constant reveals that fully depleted silicon-on-insulator (FD-SOI) channels with a modest remnant polarization P r (3 µC/cm2 at most) are more suitable for realizing SS HfO2-based ferroelectric materials. We also confirm SS ferroelectric HfO2 gate insulators by device simulation.

  20. Flow cytometry for bacteria: enabling metabolic engineering, synthetic biology and the elucidation of complex phenotypes.

    Science.gov (United States)

    Tracy, Bryan P; Gaida, Stefan M; Papoutsakis, Eleftherios T

    2010-02-01

    Flow cytometry (FC) and FC-based cell sorting have been established as critical tools in modern cell and developmental biology. Yet, their applications in bacteria, especially in the multiparametric mode, remain limited. We argue that FC technologies have the potential to greatly accelerate the analysis and development of microbial complex phenotypes through applications of metabolic engineering, synthetic biology, and evolutionary engineering. We demonstrate the importance of FC for elucidating population heterogeneity because of developmental processes or epigenetic regulation. FC can be engaged for both synthetic and analytical applications of complex phenotypes within a single species, multispecies, and microbial-library populations. Examples include methods to identify developmental microbial stages associated with productive metabolic phenotypes, select desirable promoters from a single species or metagenomic libraries, and to screen designer riboswitches for synthetic-biology applications.

  1. MODERN FEATURES OF THE MECHANICAL ENGINEERING COMPLEX ENTERPRISES TECHNICAL DEVELOPMENT WITH INTELLECTUAL POTENTIAL USE

    Directory of Open Access Journals (Sweden)

    Elena Vitalyevna Shkarupeta

    2015-12-01

    Full Text Available The purpose of the present article is the research of a current state of the mechanical engineering complex enterprises technical development from the position of intellectual potential use, detection of the technical development features in conditions of knowledge economy.Research method is desk researches when statistical information for the last 10–15 years, standard and the acts regulating technical, scientific and technological policy of the Russian Federation were analysed.Results of research are the characteristic of scientific and technical capacity of the Russian Federation from 1995 to 2015, determination of technical development relevance at the present stage of knowledge economy development.Further researches of the organizational management of mechanical engineering complex enterprises technical development with intellectual potential use have to become a scope of results.

  2. Complex Adaptive Systems of Systems (CASoS) engineering and foundations for global design.

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, Nancy S.; Finley, Patrick D.; Beyeler, Walter Eugene; Brown, Theresa Jean; Linebarger, John Michael; Moore, Thomas W.; Glass, Robert John, Jr.; Maffitt, S. Louise; Mitchell, Michael David; Ames, Arlo Leroy

    2012-01-01

    Complex Adaptive Systems of Systems, or CASoS, are vastly complex ecological, sociological, economic and/or technical systems which must be recognized and reckoned with to design a secure future for the nation and the world. Design within CASoS requires the fostering of a new discipline, CASoS Engineering, and the building of capability to support it. Towards this primary objective, we created the Phoenix Pilot as a crucible from which systemization of the new discipline could emerge. Using a wide range of applications, Phoenix has begun building both theoretical foundations and capability for: the integration of Applications to continuously build common understanding and capability; a Framework for defining problems, designing and testing solutions, and actualizing these solutions within the CASoS of interest; and an engineering Environment required for 'the doing' of CASoS Engineering. In a secondary objective, we applied CASoS Engineering principles to begin to build a foundation for design in context of Global CASoS

  3. A Model-Based Approach to Engineering Behavior of Complex Aerospace Systems

    Science.gov (United States)

    Ingham, Michel; Day, John; Donahue, Kenneth; Kadesch, Alex; Kennedy, Andrew; Khan, Mohammed Omair; Post, Ethan; Standley, Shaun

    2012-01-01

    One of the most challenging yet poorly defined aspects of engineering a complex aerospace system is behavior engineering, including definition, specification, design, implementation, and verification and validation of the system's behaviors. This is especially true for behaviors of highly autonomous and intelligent systems. Behavior engineering is more of an art than a science. As a process it is generally ad-hoc, poorly specified, and inconsistently applied from one project to the next. It uses largely informal representations, and results in system behavior being documented in a wide variety of disparate documents. To address this problem, JPL has undertaken a pilot project to apply its institutional capabilities in Model-Based Systems Engineering to the challenge of specifying complex spacecraft system behavior. This paper describes the results of the work in progress on this project. In particular, we discuss our approach to modeling spacecraft behavior including 1) requirements and design flowdown from system-level to subsystem-level, 2) patterns for behavior decomposition, 3) allocation of behaviors to physical elements in the system, and 4) patterns for capturing V&V activities associated with behavioral requirements. We provide examples of interesting behavior specification patterns, and discuss findings from the pilot project.

  4. Microfabrication of complex porous tissue engineering scaffolds using 3D projection stereolithography.

    Science.gov (United States)

    Gauvin, Robert; Chen, Ying-Chieh; Lee, Jin Woo; Soman, Pranav; Zorlutuna, Pinar; Nichol, Jason W; Bae, Hojae; Chen, Shaochen; Khademhosseini, Ali

    2012-05-01

    The success of tissue engineering will rely on the ability to generate complex, cell seeded three-dimensional (3D) structures. Therefore, methods that can be used to precisely engineer the architecture and topography of scaffolding materials will represent a critical aspect of functional tissue engineering. Previous approaches for 3D scaffold fabrication based on top-down and process driven methods are often not adequate to produce complex structures due to the lack of control on scaffold architecture, porosity, and cellular interactions. The proposed projection stereolithography (PSL) platform can be used to design intricate 3D tissue scaffolds that can be engineered to mimic the microarchitecture of tissues, based on computer aided design (CAD). The PSL system was developed, programmed and optimized to fabricate 3D scaffolds using gelatin methacrylate (GelMA). Variation of the structure and prepolymer concentration enabled tailoring the mechanical properties of the scaffolds. A dynamic cell seeding method was utilized to improve the coverage of the scaffold throughout its thickness. The results demonstrated that the interconnectivity of pores allowed for uniform human umbilical vein endothelial cells (HUVECs) distribution and proliferation in the scaffolds, leading to high cell density and confluency at the end of the culture period. Moreover, immunohistochemistry results showed that cells seeded on the scaffold maintained their endothelial phenotype, demonstrating the biological functionality of the microfabricated GelMA scaffolds.

  5. Complex Adaptive System of Systems (CASoS) Engineering Applications. Version 1.0.

    Energy Technology Data Exchange (ETDEWEB)

    Linebarger, John Michael; Maffitt, S. Louise (New Mexico Institute of Mining and Technology, Albuquerque, NM); Glass, Robert John, Jr.; Beyeler, Walter Eugene; Brown, Theresa Jean; Ames, Arlo Leroy

    2011-10-01

    Complex Adaptive Systems of Systems, or CASoS, are vastly complex eco-socio-economic-technical systems which we must understand to design a secure future for the nation and the world. Perturbations/disruptions in CASoS have the potential for far-reaching effects due to highly-saturated interdependencies and allied vulnerabilities to cascades in associated systems. The Phoenix initiative approaches this high-impact problem space as engineers, devising interventions (problem solutions) that influence CASoS to achieve specific aspirations. CASoS embody the world's biggest problems and greatest opportunities: applications to real world problems are the driving force of our effort. We are developing engineering theory and practice together to create a discipline that is grounded in reality, extends our understanding of how CASoS behave, and allows us to better control those behaviors. Through application to real-world problems, Phoenix is evolving CASoS Engineering principles while growing a community of practice and the CASoS engineers to populate it.

  6. Phase transitions via selective elemental vacancy engineering in complex oxide thin films

    Science.gov (United States)

    Lee, Sang A.; Jeong, Hoidong; Woo, Sungmin; Hwang, Jae-Yeol; Choi, Si-Young; Kim, Sung-Dae; Choi, Minseok; Roh, Seulki; Yu, Hosung; Hwang, Jungseek; Kim, Sung Wng; Choi, Woo Seok

    2016-04-01

    Defect engineering has brought about a unique level of control for Si-based semiconductors, leading to the optimization of various opto-electronic properties and devices. With regard to perovskite transition metal oxides, O vacancies have been a key ingredient in defect engineering, as they play a central role in determining the crystal field and consequent electronic structure, leading to important electronic and magnetic phase transitions. Therefore, experimental approaches toward understanding the role of defects in complex oxides have been largely limited to controlling O vacancies. In this study, we report on the selective formation of different types of elemental vacancies and their individual roles in determining the atomic and electronic structures of perovskite SrTiO3 (STO) homoepitaxial thin films fabricated by pulsed laser epitaxy. Structural and electronic transitions have been achieved via selective control of the Sr and O vacancy concentrations, respectively, indicating a decoupling between the two phase transitions. In particular, O vacancies were responsible for metal-insulator transitions, but did not influence the Sr vacancy induced cubic-to-tetragonal structural transition in epitaxial STO thin film. The independent control of multiple phase transitions in complex oxides by exploiting selective vacancy engineering opens up an unprecedented opportunity toward understanding and customizing complex oxide thin films.

  7. Automation of a neutron diffractometer for analysis of residual stress inside complex engineering components

    Science.gov (United States)

    Ganguly, S.; James, J. A.; Fitzpatrick, M. E.; Tanguy, A.

    2010-06-01

    Residual stress measurement using neutron diffraction is becoming an increasingly important tool in engineering stress analysis. To this effect, a new generation of dedicated engineering strain instruments are being built at neutron sources, offering considerable improvements in both counting time and spatial resolution. Alongside these improvements, measurements in complex geometry prototype components are increasingly in demand. As a result, there is a strong drive towards integrated sample positioning systems that allow for simplified setup and operating of experiments on components with complex geometries. The present study details work carried out at the ENGIN-X instrument at the UK’s ISIS pulsed neutron source, on measurements in a prototype metal matrix composite (MMC) aircraft wheel, forged from a billet produced through a powder-metallurgy route. The measurement was designed to obtain the macrostress and misfit stresses developed in the matrix and in the reinforcement phase in the wheel during fabrication. The study also demonstrates the use of the SScanSS software for experimental design and implementation, which was developed to complement the advances in the instrumentation of new strain mapping diffractometers. SScanSS simplifies the precise spatial location of the measuring gauge volume inside such complex components.

  8. Complex structure of engineered modular domains defining molecular interaction between ICAM-1 and integrin LFA-1.

    Directory of Open Access Journals (Sweden)

    Sungkwon Kang

    Full Text Available Intermolecular contacts between integrin LFA-1 (α(Lβ(2 and ICAM-1 derive solely from the integrin α(L I domain and the first domain (D1 of ICAM-1. This study presents a crystal structure of the engineered complex of the α(L I domain and ICAM-1 D1. Previously, we engineered the I domain for high affinity by point mutations that were identified by a directed evolution approach. In order to examine α(L I domain allostery between the C-terminal α7-helix (allosteric site and the metal-ion dependent adhesion site (active site, we have chosen a high affinity variant without mutations directly influencing either the position of the α7-helix or the active sites. In our crystal, the α(L I domain was found to have a high affinity conformation to D1 with its α7-helix displaced downward away from the binding interface, recapitulating a current understanding of the allostery in the I domain and its linkage to neighboring domains of integrins in signaling. To enable soluble D1 of ICAM-1 to fold on its own, we also engineered D1 to be functional by mutations, which were found to be those that would convert hydrogen bond networks in the solvent-excluded core into vdW contacts. The backbone structure of the β-sandwich fold and the epitope for I domain binding of the engineered D1 were essentially identical to those of wild-type D1. Most deviations in engineered D1 were found in the loops at the N-terminal region that interacts with human rhinovirus (HRV. Structural deviation found in engineered D1 was overall in agreement with the function of engineered D1 observed previously, i.e., full capacity binding to α(L I domain but reduced interaction with HRV.

  9. Transition metals (Ti and Co) in silicon and their complexes with hydrogen: A Laplace DLTS study

    Energy Technology Data Exchange (ETDEWEB)

    Kolkovsky, Vl., E-mail: kolkov@ifpan.edu.pl; Scheffler, L.; Weber, J.

    2014-04-15

    The electrical properties of transition metals (TM) in Si were often determined by means of the conventional deep level transient spectroscopy (DLTS) technique. In the present study we demonstrate that the poor resolution of the conventional DLTS technique could lead to the wrong interpretation of the experimental data. On the example of well-known lifetime killers such as titanium and cobalt we show that the dominant defects appeared in samples doped with these impurities were previously wrongly attributed to different charged states of interstitial Ti and substitutional Co. Applying the high-resolution Laplace DLTS technique we re-examine the origin of these defects. Some of these defects will be shown to react with H and shallow acceptors leading to the appearance of new complex defects in the band gap of Si. Their nature will also be discussed in the present paper.

  10. Transition metals (Ti and Co) in silicon and their complexes with hydrogen: A Laplace DLTS study

    Science.gov (United States)

    Kolkovsky, Vl.; Scheffler, L.; Weber, J.

    2014-04-01

    The electrical properties of transition metals (TM) in Si were often determined by means of the conventional deep level transient spectroscopy (DLTS) technique. In the present study we demonstrate that the poor resolution of the conventional DLTS technique could lead to the wrong interpretation of the experimental data. On the example of well-known lifetime killers such as titanium and cobalt we show that the dominant defects appeared in samples doped with these impurities were previously wrongly attributed to different charged states of interstitial Ti and substitutional Co. Applying the high-resolution Laplace DLTS technique we re-examine the origin of these defects. Some of these defects will be shown to react with H and shallow acceptors leading to the appearance of new complex defects in the band gap of Si. Their nature will also be discussed in the present paper.

  11. Synthesis, Characterization, and Biotoxicity of NN ⌢ Donor Sulphonamide Imine Silicon(IV Complexes

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available The organosilicon derivatives of 2 -[ 1 -( 2 -furaylethyledene]sulphathiazole with organosilicon chlorides have been synthesised and characterized on the basis of analytical, conductance, and spectroscopic techniques. Probable trigonal bipyramidal and octahedral structures for the resulting derivatives have been proposed on the basis of electronic, IR, 1 H , 13 C NMR, and 29 Si NMR spectral studies. In the search for better fungicides, bactericides, nematicides, and insecticides studies were conducted to assess the growth-inhibiting potential of the synthesized complexes against various pathogenic fungal, bacterial strains, root-knot nematode Meloidogyne incognita, and insect Trogoderma granarium These studies demonstrate that the concentrations reached levels which are sufficient to inhibit and kill the pathogens, nematode, and insect.

  12. Developing a framework for qualitative engineering: Research in design and analysis of complex structural systems

    Science.gov (United States)

    Franck, Bruno M.

    1990-01-01

    The research is focused on automating the evaluation of complex structural systems, whether for the design of a new system or the analysis of an existing one, by developing new structural analysis techniques based on qualitative reasoning. The problem is to identify and better understand: (1) the requirements for the automation of design, and (2) the qualitative reasoning associated with the conceptual development of a complex system. The long-term objective is to develop an integrated design-risk assessment environment for the evaluation of complex structural systems. The scope of this short presentation is to describe the design and cognition components of the research. Design has received special attention in cognitive science because it is now identified as a problem solving activity that is different from other information processing tasks (1). Before an attempt can be made to automate design, a thorough understanding of the underlying design theory and methodology is needed, since the design process is, in many cases, multi-disciplinary, complex in size and motivation, and uses various reasoning processes involving different kinds of knowledge in ways which vary from one context to another. The objective is to unify all the various types of knowledge under one framework of cognition. This presentation focuses on the cognitive science framework that we are using to represent the knowledge aspects associated with the human mind's abstraction abilities and how we apply it to the engineering knowledge and engineering reasoning in design.

  13. Laser Quenching and Ion Sulphidizing Complex Surface Treat Technology for Diesel Engine Cylinder

    Institute of Scientific and Technical Information of China (English)

    XIE Zhaoqian; ZENG Qingqiang; HUANG Huayuan; Cai Zhihai; ZHAO Yuqiang

    2012-01-01

    In order to solve the problem of wear-out-failure of diesel engine cylinder,the laser-quenching and low temperature ion sulfurizing complex surface treatment technology was operated on the surface of 42MnCr52 steel.And the tribological properties of the complex layer were investigated.The experimental results indicated that the complex layer was composed of soft surface sulphide layer and sub-surface laserquenching harden layer,and showed excellent friction-reduction and wear-resistance performance at high temperature.The synergistic effect of the complex layer resulted in 20% increase in hardness,10% reduction in friction coefficient and 50% reduction in wear weight loss,respectively,compared with those of the standard samples.The bench-test further demonstrated that this technology can improve the lubricating condition between cylinder and piston ring,and reduce both abnormity wear when the lubricating oil is deficiency at the time of start-up and sticking wear at high temperature during the operating period,and then prolong the service life of engine.

  14. Mechanically flexible optically transparent silicon fabric with high thermal budget devices from bulk silicon (100)

    KAUST Repository

    Hussain, Muhammad Mustafa

    2013-05-30

    Today’s information age is driven by silicon based electronics. For nearly four decades semiconductor industry has perfected the fabrication process of continuingly scaled transistor – heart of modern day electronics. In future, silicon industry will be more pervasive, whose application will range from ultra-mobile computation to bio-integrated medical electronics. Emergence of flexible electronics opens up interesting opportunities to expand the horizon of electronics industry. However, silicon – industry’s darling material is rigid and brittle. Therefore, we report a generic batch fabrication process to convert nearly any silicon electronics into a flexible one without compromising its (i) performance; (ii) ultra-large-scale-integration complexity to integrate billions of transistors within small areas; (iii) state-of-the-art process compatibility, (iv) advanced materials used in modern semiconductor technology; (v) the most widely used and well-studied low-cost substrate mono-crystalline bulk silicon (100). In our process, we make trenches using anisotropic reactive ion etching (RIE) in the inactive areas (in between the devices) of a silicon substrate (after the devices have been fabricated following the regular CMOS process), followed by a dielectric based spacer formation to protect the sidewall of the trench and then performing an isotropic etch to create caves in silicon. When these caves meet with each other the top portion of the silicon with the devices is ready to be peeled off from the bottom silicon substrate. Release process does not need to use any external support. Released silicon fabric (25 μm thick) is mechanically flexible (5 mm bending radius) and the trenches make it semi-transparent (transparency of 7%). © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  15. Complex dynamics of our economic life on different scales: insights from search engine query data.

    Science.gov (United States)

    Preis, Tobias; Reith, Daniel; Stanley, H Eugene

    2010-12-28

    Search engine query data deliver insight into the behaviour of individuals who are the smallest possible scale of our economic life. Individuals are submitting several hundred million search engine queries around the world each day. We study weekly search volume data for various search terms from 2004 to 2010 that are offered by the search engine Google for scientific use, providing information about our economic life on an aggregated collective level. We ask the question whether there is a link between search volume data and financial market fluctuations on a weekly time scale. Both collective 'swarm intelligence' of Internet users and the group of financial market participants can be regarded as a complex system of many interacting subunits that react quickly to external changes. We find clear evidence that weekly transaction volumes of S&P 500 companies are correlated with weekly search volume of corresponding company names. Furthermore, we apply a recently introduced method for quantifying complex correlations in time series with which we find a clear tendency that search volume time series and transaction volume time series show recurring patterns.

  16. Phoenix : Complex Adaptive System of Systems (CASoS) engineering version 1.0.

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Thomas W.; Quach, Tu-Thach; Detry, Richard Joseph; Conrad, Stephen Hamilton; Kelic, Andjelka; Starks, Shirley J.; Beyeler, Walter Eugene; Brodsky, Nancy S.; Verzi, Stephen J.; Brown, Theresa Jean; Glass, Robert John, Jr.; Sunderland, Daniel J.; Mitchell, Michael David; Ames, Arlo Leroy; Maffitt, S. Louise; Finley, Patrick D.; Russell, Eric Dean; Zagonel, Aldo A.; Reedy, Geoffrey E.; Mitchell, Roger A.; Corbet, Thomas Frank, Jr.; Linebarger, John Michael

    2011-08-01

    Complex Adaptive Systems of Systems, or CASoS, are vastly complex ecological, sociological, economic and/or technical systems which we must understand to design a secure future for the nation and the world. Perturbations/disruptions in CASoS have the potential for far-reaching effects due to pervasive interdependencies and attendant vulnerabilities to cascades in associated systems. Phoenix was initiated to address this high-impact problem space as engineers. Our overarching goals are maximizing security, maximizing health, and minimizing risk. We design interventions, or problem solutions, that influence CASoS to achieve specific aspirations. Through application to real-world problems, Phoenix is evolving the principles and discipline of CASoS Engineering while growing a community of practice and the CASoS engineers to populate it. Both grounded in reality and working to extend our understanding and control of that reality, Phoenix is at the same time a solution within a CASoS and a CASoS itself.

  17. Significance of chamber pressure to complex multi-phase physics in jet engine fuel injection processes

    Science.gov (United States)

    Dahms, Rainer; Oefelein, Joseph

    2014-11-01

    Injection processes in jet engines at chamber pressures in excess of the thermodynamic critical pressure of the liquid fuel are not well understood. Under some conditions, a distinct two-phase interface may not exist anymore which eliminates the presence of classical spray atomization phenomena. A comprehensive model for jet engine fuel injections is derived to quantify the conditions under which the interfacial dynamics transition to diffusion-dominated mixing processes without surface tension. At certain conditions, the model shows two-phase interfaces with substantially increased thicknesses and distinctively reduced mean free paths in comparison to ambient pressure conditions. Then, the underlying assumptions of a distinct two-phase interface do not apply anymore and the interface along with its surface tension is shown to deteriorate as it broadens substantially. As a consequence of this physical complexity, the conceptual view of spray atomization and evaporation as an appropriate model for jet engine injection processes is, contrary to conventional wisdom, questionable at certain operating conditions. Instead, a Large Eddy Simulation using a dense-fluid approximation is applied which takes the complex thermo-physics of real-fluid behavior into account.

  18. Ethical education in software engineering: responsibility in the production of complex systems.

    Science.gov (United States)

    Génova, Gonzalo; González, M Rosario; Fraga, Anabel

    2007-12-01

    Among the various contemporary schools of moral thinking, consequence-based ethics, as opposed to rule-based, seems to have a good acceptance among professionals such as software engineers. But naïve consequentialism is intellectually too weak to serve as a practical guide in the profession. Besides, the complexity of software systems makes it very hard to know in advance the consequences that will derive from professional activities in the production of software. Therefore, following the spirit of well-known codes of ethics such as the ACM/IEEE's, we advocate for a more solid position in the ethical education of software engineers, which we call 'moderate deontologism', that takes into account both rules and consequences to assess the goodness of actions, and at the same time pays an adequate consideration to the absolute values of human dignity. In order to educate responsible professionals, however, this position should be complemented with a pedagogical approach to virtue ethics.

  19. Pre-decommissioning complex engineering and radiation inspection of the WWR-M reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lobach, Yuri N.; Shevel, Valery N. [NASU, Kiev (Ukraine). Inst. for Nuclear Research

    2014-04-15

    The Kiev's research reactor WWR-M has been in operation for more than 50 years. Decommissioning plan should to be prepared and approved before the beginning of the decommissioning activities. A key activity during reactor operation is implementing the pre-decommissioning complex engineering and radiation inspection. It should be done with objective to collect, arrange and analyze the data related to the engineering and radiation conditions of the reactor systems and equipment. Recently, such an inspection has been completed. The analysis of available documentation has consisted in the assessment of design, construction, technological, assembling, operation, maintenance and repair documentation for each system. The radiation survey was performed in two different ways, namely, by doing the experimental measurements and by performing calculations. The collected data are provided a comprehensive technical basis for the development of decommissioning documentation which is required for the planning and implementation of the reactor decommissioning. (orig.)

  20. A Case Study: Application of the Systems Engineering Modeling in the early phases of a Complex Space System Project

    NARCIS (Netherlands)

    Bone, M.; Cloutier, R.L.; Gill, E.K.A.; Verma, D.

    2009-01-01

    There is increased recognition of the role of systems engineering in reducing the risk (technical, cost, and schedule) on complex space systems development and integration projects. A number of international systems engineering standards have been published in the last five years (ISO 15288, IEEE 12

  1. A Case Study: Application of the Systems Engineering Modeling in the early phases of a Complex Space System Project

    NARCIS (Netherlands)

    Bone, M.; Cloutier, R.L.; Gill, E.K.A.; Verma, D.

    2009-01-01

    There is increased recognition of the role of systems engineering in reducing the risk (technical, cost, and schedule) on complex space systems development and integration projects. A number of international systems engineering standards have been published in the last five years (ISO 15288, IEEE 12

  2. A Measure of Systems Engineering Effectiveness in Government Acquisition of Complex Information Systems: A Bayesian Belief Network-Based Approach

    Science.gov (United States)

    Doskey, Steven Craig

    2014-01-01

    This research presents an innovative means of gauging Systems Engineering effectiveness through a Systems Engineering Relative Effectiveness Index (SE REI) model. The SE REI model uses a Bayesian Belief Network to map causal relationships in government acquisitions of Complex Information Systems (CIS), enabling practitioners to identify and…

  3. Modular fabrication and characterization of complex silicon carbide composite structures Advanced Reactor Technologies (ART) Research Final Report (Feb 2015 – May 2017)

    Energy Technology Data Exchange (ETDEWEB)

    Khalifa, Hesham [General Atomics, San Diego, CA (United States)

    2017-08-03

    Advanced ceramic materials exhibit properties that enable safety and fuel cycle efficiency improvements in advanced nuclear reactors. In order to fully exploit these desirable properties, new processing techniques are required to produce the complex geometries inherent to nuclear fuel assemblies and support structures. Through this project, the state of complex SiC-SiC composite fabrication for nuclear components has advanced significantly. New methods to produce complex SiC-SiC composite structures have been demonstrated in the form factors needed for in-core structural components in advanced high temperature nuclear reactors. Advanced characterization techniques have been employed to demonstrate that these complex SiC-SiC composite structures provide the strength, toughness and hermeticity required for service in harsh reactor conditions. The complex structures produced in this project represent a significant step forward in leveraging the excellent high temperature strength, resistance to neutron induced damage, and low neutron cross section of silicon carbide in nuclear applications.

  4. Free Energy Minimization Calculation of Complex Chemical Equilibria. Reduction of Silicon Dioxide with Carbon at High Temperature.

    Science.gov (United States)

    Wai, C. M.; Hutchinson, S. G.

    1989-01-01

    Discusses the calculation of free energy in reactions between silicon dioxide and carbon. Describes several computer programs for calculating the free energy minimization and their uses in chemistry classrooms. Lists 16 references. (YP)

  5. Structures of coxsackievirus, rhinovirus, and poliovirus polymerase elongation complexes solved by engineering RNA mediated crystal contacts.

    Science.gov (United States)

    Gong, Peng; Kortus, Matthew G; Nix, Jay C; Davis, Ralph E; Peersen, Olve B

    2013-01-01

    RNA-dependent RNA polymerases play a vital role in the growth of RNA viruses where they are responsible for genome replication, but do so with rather low fidelity that allows for the rapid adaptation to different host cell environments. These polymerases are also a target for antiviral drug development. However, both drug discovery efforts and our understanding of fidelity determinants have been hampered by a lack of detailed structural information about functional polymerase-RNA complexes and the structural changes that take place during the elongation cycle. Many of the molecular details associated with nucleotide selection and catalysis were revealed in our recent structure of the poliovirus polymerase-RNA complex solved by first purifying and then crystallizing stalled elongation complexes. In the work presented here we extend that basic methodology to determine nine new structures of poliovirus, coxsackievirus, and rhinovirus elongation complexes at 2.2-2.9 Å resolution. The structures highlight conserved features of picornaviral polymerases and the interactions they make with the template and product RNA strands, including a tight grip on eight basepairs of the nascent duplex, a fully pre-positioned templating nucleotide, and a conserved binding pocket for the +2 position template strand base. At the active site we see a pre-bound magnesium ion and there is conservation of a non-standard backbone conformation of the template strand in an interaction that may aid in triggering RNA translocation via contact with the conserved polymerase motif B. Moreover, by engineering plasticity into RNA-RNA contacts, we obtain crystal forms that are capable of multiple rounds of in-crystal catalysis and RNA translocation. Together, the data demonstrate that engineering flexible RNA contacts to promote crystal lattice formation is a versatile platform that can be used to solve the structures of viral RdRP elongation complexes and their catalytic cycle intermediates.

  6. Structures of coxsackievirus, rhinovirus, and poliovirus polymerase elongation complexes solved by engineering RNA mediated crystal contacts.

    Directory of Open Access Journals (Sweden)

    Peng Gong

    Full Text Available RNA-dependent RNA polymerases play a vital role in the growth of RNA viruses where they are responsible for genome replication, but do so with rather low fidelity that allows for the rapid adaptation to different host cell environments. These polymerases are also a target for antiviral drug development. However, both drug discovery efforts and our understanding of fidelity determinants have been hampered by a lack of detailed structural information about functional polymerase-RNA complexes and the structural changes that take place during the elongation cycle. Many of the molecular details associated with nucleotide selection and catalysis were revealed in our recent structure of the poliovirus polymerase-RNA complex solved by first purifying and then crystallizing stalled elongation complexes. In the work presented here we extend that basic methodology to determine nine new structures of poliovirus, coxsackievirus, and rhinovirus elongation complexes at 2.2-2.9 Å resolution. The structures highlight conserved features of picornaviral polymerases and the interactions they make with the template and product RNA strands, including a tight grip on eight basepairs of the nascent duplex, a fully pre-positioned templating nucleotide, and a conserved binding pocket for the +2 position template strand base. At the active site we see a pre-bound magnesium ion and there is conservation of a non-standard backbone conformation of the template strand in an interaction that may aid in triggering RNA translocation via contact with the conserved polymerase motif B. Moreover, by engineering plasticity into RNA-RNA contacts, we obtain crystal forms that are capable of multiple rounds of in-crystal catalysis and RNA translocation. Together, the data demonstrate that engineering flexible RNA contacts to promote crystal lattice formation is a versatile platform that can be used to solve the structures of viral RdRP elongation complexes and their catalytic cycle

  7. Raman analysis of DLC coated engine components with complex shape: Understanding wear mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Jaoul, C., E-mail: jaoul@ensil.unilim.f [Universite de Limoges, CNRS, Sciences des Procedes Ceramiques et de Traitements de Surface, ENSIL, Parc Ester Technopole, 16 rue d' Atlantis, BP 6804, 87068 Limoges Cedex (France); Jarry, O. [Universite de Limoges, CNRS, Sciences des Procedes Ceramiques et de Traitements de Surface, ENSIL, Parc Ester Technopole, 16 rue d' Atlantis, BP 6804, 87068 Limoges Cedex (France); Sorevi, Parc Ester Technopole, 5 Allee Skylab, BP 6810, 87068 Limoges (France); Tristant, P. [Universite de Limoges, CNRS, Sciences des Procedes Ceramiques et de Traitements de Surface, ENSIL, Parc Ester Technopole, 16 rue d' Atlantis, BP 6804, 87068 Limoges Cedex (France); Merle-Mejean, T.; Colas, M. [Universite de Limoges, CNRS, Sciences des Procedes Ceramiques et de Traitements de Surface, Faculty of Sciences and Technics, 123 avenue Albert Thomas, 87060 Limoges Cedex (France); Dublanche-Tixier, C. [Universite de Limoges, CNRS, Sciences des Procedes Ceramiques et de Traitements de Surface, ENSIL, Parc Ester Technopole, 16 rue d' Atlantis, BP 6804, 87068 Limoges Cedex (France); Jacquet, J.-M. [Sorevi, Parc Ester Technopole, 5 Allee Skylab, BP 6810, 87068 Limoges (France)

    2009-12-31

    Hydrogenated amorphous carbon (a-C:H) films were deposited on flat samples and engine components using an industrial scale reactor. Characterization of the coating allowed validating its application on engine parts due to high hardness (32 GPa) and high level of adhesion achieved using sublayers. The original approach of this work concerned the use of Raman analysis not only on flat samples after tribometer tests but also directly on coated engine parts with complex shape (like cam/follower system), in order to understand wear mechanisms occurring in motorsport engines. As wear could lead to a coating thickness decrease, a particular attention was paid on the Raman signal of the sublayers. Among the different values extracted from Raman spectrum to characterize structural organization, the value of G peak intensity appeared as a criterion of validity of analyses because it is directly linked to the remaining thickness of the a-C:H layer. For flat samples tested on ball-on-disc tribometer, structure of a-C:H film observed by Raman spectroscopy in the wear track remained stable in depth. Then, a-C:H coated engine components were studied before and after working in real conditions. Two different wear mechanisms were identified. The first one did not show any structural modification of the bulk a-C:H layer. In the second one, the high initial roughness of samples (R{sub t} = 1.15 {mu}m) lead to coating delaminations after sliding. Massive graphitization which decreases drastically mechanical properties of the coatings was observed by Raman analyses on the contact area. The increase of the temperature on rough edges of the scratches could explain this graphitization.

  8. System Coordination of Survivability and Safety of Complex Engineering Objects Operation

    Directory of Open Access Journals (Sweden)

    Nataliya Pankratova

    2014-11-01

    Full Text Available A system strategy to estimation the guaranteed survivability and safety of complex engineering objects (CEO operation is proposed. The principles that underlie the strategy of the guaranteed safety of CEO operation provide a flexible approach to timely detection, recognition, forecast, and system diagnostics of risk factors and situations, to formulation and implementation of a rational decision in a practicable time within an unremovable time constraint. Implementation of the proposed strategy is shown on example of diagnostics of electromobile-refrigerator functioning in real mode.

  9. Multi-disciplinary engineering for cyber-physical production systems data models and software solutions for handling complex engineering projects

    CERN Document Server

    Lüder, Arndt; Gerhard, Detlef

    2017-01-01

    This book discusses challenges and solutions for the required information processing and management within the context of multi-disciplinary engineering of production systems. The authors consider methods, architectures, and technologies applicable in use cases according to the viewpoints of product engineering and production system engineering, and regarding the triangle of (1) product to be produced by a (2) production process executed on (3) a production system resource. With this book industrial production systems engineering researchers will get a better understanding of the challenges and requirements of multi-disciplinary engineering that will guide them in future research and development activities. Engineers and managers from engineering domains will be able to get a better understanding of the benefits and limitations of applicable methods, architectures, and technologies for selected use cases. IT researchers will be enabled to identify research issues related to the development of new methods, arc...

  10. Complexes associated with silicon and hydrogen in the neutralization mechanism of active donors in hydrogenated GaAs: Si(n)

    Energy Technology Data Exchange (ETDEWEB)

    Chevallier, J.; Jalil, A.; Pesant, J.C.; Mostefaoui, R.; Pajot, B.; Murawala, P.; Azoulay, R.

    1987-08-01

    After hydrogen plasma exposure of a n type GaAs:Si crystal, we observe a decrease of the free carrier concentration and a hydrogen diffusion in the near surface region of the material. In bulk crystals, a good correlation has been established between the hydrogen penetration depth and the depth where the free carrier concentration recovers its bulk value. The decrease of the carrier concentration is accompanied by a significant increase of the electron mobility. This increase reveals a neutralization of the active donors and their transformation into electrically neutral complexes. A detailed infrared spectroscopy study on plasma exposed GaAs:Si epilayers shows a very sharp absorption line at 890 cm/sup -1/ on hydrogenated samples and 637 cm/sup -1/ on deuterated samples. These bands are totally absent in hydrogenated undoped GaAs. The isotopic shift frequency analysis indicates that the 890 cm/sup -1/ line could be associated with an arsenic-hydrogen bond where arsenic is supposed to sit as a first nearest neighbour of a silicon donor. Isochronal annealing experiments show a good correlation between the 890 cm/sup -1/ absorption band intensity and the neutralized silicon donor concentration. The neutralization would be due to the formation of (SiAs/sub 3/) As-H complexes, the extra electron of the silicon donor being trapped in order to participate to the As-H bond.

  11. Engineering a large application software project: the controls of the CERN PS accelerator complex

    Energy Technology Data Exchange (ETDEWEB)

    Benincasa, G.P.; Daneels, A.; Heymans, P.; Serre, Ch.

    1985-10-01

    The CERN PS accelerator complex has been progressively converted to full computer controls without interrupting its full-time operation (more than 6000 hours per year with on average not more than 1% of the total down-time due to controls). The application software amounts to 120 man-years and 450'000 instructions: it compares with other large software projects, also outside the accelerator world: e.g. Skylab's ground support software. This paper outlines the application software structure which takes into account technical requirements and constraints (resulting from the complexity of the process and its operation) and economical and managerial ones. It presents the engineering and management techniques used to promote implementation, testing and commissioning within budget, manpower and time constraints and concludes with experience gained.

  12. Model-based system engineering approach for the Euclid mission to manage scientific and technical complexity

    Science.gov (United States)

    Lorenzo Alvarez, Jose; Metselaar, Harold; Amiaux, Jerome; Saavedra Criado, Gonzalo; Gaspar Venancio, Luis M.; Salvignol, Jean-Christophe; Laureijs, René J.; Vavrek, Roland

    2016-08-01

    In the last years, the system engineering field is coming to terms with a paradigm change in the approach for complexity management. Different strategies have been proposed to cope with highly interrelated systems, system of systems and collaborative system engineering have been proposed and a significant effort is being invested into standardization and ontology definition. In particular, Model Based System Engineering (MBSE) intends to introduce methodologies for a systematic system definition, development, validation, deployment, operation and decommission, based on logical and visual relationship mapping, rather than traditional 'document based' information management. The practical implementation in real large-scale projects is not uniform across fields. In space science missions, the usage has been limited to subsystems or sample projects with modeling being performed 'a-posteriori' in many instances. The main hurdle for the introduction of MBSE practices in new projects is still the difficulty to demonstrate their added value to a project and whether their benefit is commensurate with the level of effort required to put them in place. In this paper we present the implemented Euclid system modeling activities, and an analysis of the benefits and limitations identified to support in particular requirement break-down and allocation, and verification planning at mission level.

  13. Visualizing and modelling complex rockfall slopes using game-engine hosted models

    Science.gov (United States)

    Ondercin, Matthew; Hutchinson, D. Jean; Harrap, Rob

    2015-04-01

    Innovations in computing in the past few decades have resulted in entirely new ways to collect 3d geological data and visualize it. For example, new tools and techniques relying on high performance computing capabilities have become widely available, allowing us to model rockfalls with more attention to complexity of the rock slope geometry and rockfall path, with significantly higher quality base data, and with more analytical options. Model results are used to design mitigation solutions, considering the potential paths of the rockfall events and the energy they impart on impacted structures. Such models are currently implemented as general-purpose GIS tools and in specialized programs. These tools are used to inspect geometrical and geomechanical data, model rockfalls, and communicate results to researchers and the larger community. The research reported here explores the notion that 3D game engines provide a high speed, widely accessible platform on which to build rockfall modelling workflows and to provide a new and accessible outreach method. Taking advantage of the in-built physics capability of the 3D game codes, and ability to handle large terrains, these models are rapidly deployed and generate realistic visualizations of rockfall trajectories. Their utility in this area is as yet unproven, but preliminary research shows that they are capable of producing results that are comparable to existing approaches. Furthermore, modelling of case histories shows that the output matches the behaviour that is observed in the field. The key advantage of game-engine hosted models is their accessibility to the general public and to people with little to no knowledge of rockfall hazards. With much of the younger generation being very familiar with 3D environments such as Minecraft, the idea of a game-like simulation is intuitive and thus offers new ways to communicate to the general public. We present results from using the Unity game engine to develop 3D voxel worlds

  14. Engineering of silicon-based ceramic fibers: Novel SiTaC(O) ceramic fibers prepared from polytantalosilane

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Z., E-mail: xiezhengfang@163.com [State Key Laboratory of Advanced Ceramic Fibers and Composites, National University of Defense Technology, Changsha 410073 (China); Cao, S.; Wang, J. [State Key Laboratory of Advanced Ceramic Fibers and Composites, National University of Defense Technology, Changsha 410073 (China); Yan, X. [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Bernard, S., E-mail: Samuel.Bernard@univ-lyon1.fr [Laboratoire des Multimateriaux et Interfaces (UMR CNRS 5615), Universite de Lyon, Universite Lyon1, 43 bd du 11 Novembre 1918, 69622 Villeurbanne Cedex (France); Miele, P. [Laboratoire des Multimateriaux et Interfaces (UMR CNRS 5615), Universite de Lyon, Universite Lyon1, 43 bd du 11 Novembre 1918, 69622 Villeurbanne Cedex (France)

    2010-10-15

    Research highlights: {yields} This paper reports the preparation and characterization of a novel variety of silicon-based ceramic fibers. {yields} In the present paper, we provide a detailed picture of the preparation process of SiTaC(O) ceramic fibers from a polytantalosilane. {yields} We have fully characterized the polymer by FT-IR, NMR, chemical composition, GPC and TGA as well as the chemical composition, the structure, the texture, and the mechanical properties of the ceramic fibers by XPS, SEM, X-ray diffraction (XRD), and mechanical tests. - Abstract: A novel variety of silicon-based ceramic fibers has been prepared from a preceramic organosilicon polymers called polytantalocarbosilane (PTaCS). This melt-spinnable polymer has been synthesized by thermally induced reactions between tantalum (V) tetraethoxyacetylacetonate (Ta(Acac)(OEt){sub 4}) and polysilacarbosilane (PSCS). The polymer in which [-Si-C-]{sub n} chains are crosslinked via Ta-containing bridges as identified by infrared spectroscopy, XPS and NMR, is decomposed in high ceramic yield (76%) and can be spun in the molten state into fibers to be cured in air then pyrolyzed in flowing nitrogen at 1200 deg. C into amorphous SiTaC(O) fibers. Complete characterization of this new generation of silicon-based ceramic fibers was made based on mechanical tests, XRD and SEM. These fibers exhibit relatively good mechanical properties and excellent high-temperature stability with good oxidation resistance.

  15. Genome-scale transcriptional activation by an engineered CRISPR-Cas9 complex.

    Science.gov (United States)

    Konermann, Silvana; Brigham, Mark D; Trevino, Alexandro E; Joung, Julia; Abudayyeh, Omar O; Barcena, Clea; Hsu, Patrick D; Habib, Naomi; Gootenberg, Jonathan S; Nishimasu, Hiroshi; Nureki, Osamu; Zhang, Feng

    2015-01-29

    Systematic interrogation of gene function requires the ability to perturb gene expression in a robust and generalizable manner. Here we describe structure-guided engineering of a CRISPR-Cas9 complex to mediate efficient transcriptional activation at endogenous genomic loci. We used these engineered Cas9 activation complexes to investigate single-guide RNA (sgRNA) targeting rules for effective transcriptional activation, to demonstrate multiplexed activation of ten genes simultaneously, and to upregulate long intergenic non-coding RNA (lincRNA) transcripts. We also synthesized a library consisting of 70,290 guides targeting all human RefSeq coding isoforms to screen for genes that, upon activation, confer resistance to a BRAF inhibitor. The top hits included genes previously shown to be able to confer resistance, and novel candidates were validated using individual sgRNA and complementary DNA overexpression. A gene expression signature based on the top screening hits correlated with markers of BRAF inhibitor resistance in cell lines and patient-derived samples. These results collectively demonstrate the potential of Cas9-based activators as a powerful genetic perturbation technology.

  16. Liquid-Phase Laser Induced Forward Transfer for Complex Organic Inks and Tissue Engineering.

    Science.gov (United States)

    Nguyen, Alexander K; Narayan, Roger J

    2017-01-01

    Laser induced forward transfer (LIFT) acts as a novel alternative to incumbent plotting techniques such as inkjet printing due to its ability to precisely deposit and position picoliter-sized droplets while being gentle enough to preserve sensitive structures within the ink. Materials as simple as screen printing ink to complex eukaryotic cells have been printed with applications spanning from microelectronics to tissue engineering. Biotechnology can benefit from this technique due to the efficient use of low volumes of reagent and the compatibility with a wide range of rheological properties. In addition, LIFT can be performed in a simple lab environment, not requiring vacuum or other extreme conditions. Although the basic apparatus is simple, many strategies exist to optimize the performance considering the ink and the desired pattern. The basic mechanism is similar between studies so the large number of variants can be summarized into a couple of categories and reported on with respect to their specific applications. In particular, precise and gentle deposition of complex molecules and eukaryotic cells represent the unique abilities of this technology. LIFT has demonstrated not only marked improvements in the quality of sensors and related medical devices over those manufactured with incumbent technologies but also great applicability in tissue engineering due to the high viability of printed cells.

  17. Science Outside the Lab: Helping Graduate Students in Science and Engineering Understand the Complexities of Science Policy.

    Science.gov (United States)

    Bernstein, Michael J; Reifschneider, Kiera; Bennett, Ira; Wetmore, Jameson M

    2016-09-28

    Helping scientists and engineers challenge received assumptions about how science, engineering, and society relate is a critical cornerstone for macroethics education. Scientific and engineering research are frequently framed as first steps of a value-free linear model that inexorably leads to societal benefit. Social studies of science and assessments of scientific and engineering research speak to the need for a more critical approach to the noble intentions underlying these assumptions. "Science Outside the Lab" is a program designed to help early-career scientists and engineers understand the complexities of science and engineering policy. Assessment of the program entailed a pre-, post-, and 1 year follow up survey to gauge student perspectives on relationships between science and society, as well as a pre-post concept map exercise to elicit student conceptualizations of science policy. Students leave Science Outside the Lab with greater humility about the role of scientific expertise in science and engineering policy; greater skepticism toward linear notions of scientific advances benefiting society; a deeper, more nuanced understanding of the actors involved in shaping science policy; and a continued appreciation of the contributions of science and engineering to society. The study presents an efficacious program that helps scientists and engineers make inroads into macroethical debates, reframe the ways in which they think about values of science and engineering in society, and more thoughtfully engage with critical mediators of science and society relationships: policy makers and policy processes.

  18. Silicon micro-mold

    Science.gov (United States)

    Morales, Alfredo M.

    2006-10-24

    The present invention describes a method for rapidly fabricating a robust 3-dimensional silicon-mold for use in preparing complex metal micro-components. The process begins by depositing a conductive metal layer onto one surface of a silicon wafer. A thin photoresist and a standard lithographic mask are then used to transfer a trace image pattern onto the opposite surface of the wafer by exposing and developing the resist. The exposed portion of the silicon substrate is anisotropically etched through the wafer thickness down to conductive metal layer to provide an etched pattern consisting of a series of rectilinear channels and recesses in the silicon which serve as the silicon micro-mold. Microcomponents are prepared with this mold by first filling the mold channels and recesses with a metal deposit, typically by electroplating, and then removing the silicon micro-mold by chemical etching.

  19. Engineered stealth porous silicon nanoparticles via surface encapsulation of bovine serum albumin for prolonging blood circulation in vivo.

    Science.gov (United States)

    Xia, Bing; Zhang, Wenyi; Shi, Jisen; Xiao, Shou-jun

    2013-11-27

    Luminescent porous silicon nanoparticles (PSiNPs) have been widely used as drug delivery. However, fast biodegradation and short blood circulation have been major challenges for their biomedical applications. Herein, bovine serum albumin was readily encapsulated onto alkyl-terminated PSiNPs surfaces via hydrophobic interaction, which could significantly improve their water-dispersibility and long-term stability under physiological conditions. Furthermore, compared with PSiNPs alone, PSiNPs coated with bovine serum albumin remarkably reduced nonspecific cellular uptake in vitro and prolonged blood circulation in vivo.

  20. Design of a nanomechanical fluid control valve based on functionalized silicon cantilevers: coupling molecular mechanics with classical engineering design

    OpenAIRE

    Santiago D. Solares; Blanco, Mario; Goddard, William A.

    2004-01-01

    Process engineering design relies on a host of mechanical devices that enable transport phenomena to take place under controlled conditions. These devices include pipes, valves, pumps, chemical reactors, heat exchangers, packed columns, etc. Mass, energy, and momentum transfer will also be essential phenomena in nanoprocess engineering, particularly at the interface between micro- and nanodevices. Control valves are one of the most fundamental components. In this paper we explore the design o...

  1. Effect of the order of He+ and H+ ion co-implantation on damage generation and thermal evolution of complexes, platelets, and blisters in silicon

    Science.gov (United States)

    Daghbouj, N.; Cherkashin, N.; Darras, F.-X.; Paillard, V.; Fnaiech, M.; Claverie, A.

    2016-04-01

    Hydrogen and helium co-implantation is nowadays used to efficiently transfer thin Si layers and fabricate silicon on insulator wafers for the microelectronic industry. The synergy between the two implants which is reflected through the dramatic reduction of the total fluence needed to fracture silicon has been reported to be strongly influenced by the implantation order. Contradictory conclusions on the mechanisms involved in the formation and thermal evolution of defects and complexes have been drawn. In this work, we have experimentally studied in detail the characteristics of Si samples co-implanted with He and H, comparing the defects which are formed following each implantation and after annealing. We show that the second implant always ballistically destroys the stable defects and complexes formed after the first implant and that the redistribution of these point defects among new complexes drives the final difference observed in the samples after annealing. When H is implanted first, He precipitates in the form of nano-bubbles and agglomerates within H-related platelets and nano-cracks. When He is implanted first, the whole He fluence is ultimately used to pressurize H-related platelets which quickly evolve into micro-cracks and surface blisters. We provide detailed scenarios describing the atomic mechanisms involved during and after co-implantation and annealing which well-explain our results and the reasons for the apparent contradictions reported at the state of the art.

  2. Latest Progress of Fault Detection and Localization in Complex Electrical Engineering

    Science.gov (United States)

    Zhao, Zheng; Wang, Can; Zhang, Yagang; Sun, Yi

    2014-01-01

    In the researches of complex electrical engineering, efficient fault detection and localization schemes are essential to quickly detect and locate faults so that appropriate and timely corrective mitigating and maintenance actions can be taken. In this paper, under the current measurement precision of PMU, we will put forward a new type of fault detection and localization technology based on fault factor feature extraction. Lots of simulating experiments indicate that, although there are disturbances of white Gaussian stochastic noise, based on fault factor feature extraction principal, the fault detection and localization results are still accurate and reliable, which also identifies that the fault detection and localization technology has strong anti-interference ability and great redundancy.

  3. Development of Hybrid Intelligent Systems and their Applications from Engineering Systems to Complex Systems

    CERN Document Server

    Owladeghaffari, Hamed

    2008-01-01

    In this study, we introduce general frame of MAny Connected Intelligent Particles Systems (MACIPS). Connections and interconnections between particles get a complex behavior of such merely simple system (system in system).Contribution of natural computing, under information granulation theory, are the main topic of this spacious skeleton. Upon this clue, we organize different algorithms involved a few prominent intelligent computing and approximate reasoning methods such as self organizing feature map (SOM)[9], Neuro- Fuzzy Inference System[10], Rough Set Theory (RST)[11], collaborative clustering, Genetic Algorithm and Ant Colony System. Upon this, we have employed our algorithms on the several engineering systems, especially emerged systems in Civil and Mineral processing. In other process, we investigated how our algorithms can be taken as a linkage of government-society interaction, where government catches various fashions of behavior: solid (absolute) or flexible. So, transition of such society, by chan...

  4. Introductory statistics and random phenomena uncertainty, complexity and chaotic behavior in engineering and science

    CERN Document Server

    Denker, Manfred

    2017-01-01

    Introductory Statistics and Random Phenomena integrates traditional statistical data analysis with new computational experimentation capabilities and concepts of algorithmic complexity and chaotic behavior in nonlinear dynamic systems.  This was the first advanced text/reference to bring together such a comprehensive variety of tools for the study of random phenomena occurring in engineering and the natural, life, and social sciences. The crucial computer experiments are conducted using the readily available computer program Mathematica® Uncertain Virtual Worlds™ software packages which optimize and facilitate the simulation environment.  Brief tutorials are included that explain how to use theMathematica® programs for effective simulation and computer experiments.  Large and original real-life data sets are introduced and analyzed as a model for independent study. This is an excellent classroom tool and self-study guide.  The material is presented in a clear and accessible style providing numerous...

  5. `You caught me off guard': Probing the futures of complex engineered nanomaterials

    Science.gov (United States)

    Sadowski, Jathan; Guston, David H.

    2016-07-01

    This paper applies principles and methods from the framework of anticipatory governance to the case of what the National Research Council calls "complex engineered nanomaterials" (CENM). This framework does not aim to generate crystal ball visions or definitive answers, but rather provides guidance for uncovering, understanding, and addressing social, ethical, environmental, and policy issues that stem from emerging technologies. Thus, in anticipation of increased CENM research, CENM products, and their different governance challenges, we aim to lay the groundwork for the anticipatory governance of CENMs by mapping out what—according to the engineers and scientists, we interviewed who are working at the research level of these CENMs—will be the main issues and themes that we need to pay attention to in the near future. The structured interviews focused on three groups of questions: (1) potential and/or actual applications and/or products from the participant's research; (2) environmental health and safety issues pertaining to both the participant's research and CENMs generally; and (3) the future of CENMs. Without a foundational understanding to build on, social scientists, policymakers, and regulatory agencies will be at a loss about how to govern CENMs before they are widely implemented in society.

  6. PARTICLE METHODS FOR COMPLEX FLOWS IN CHEMICAL ENGINEERING--THE PSEUDO-PARTICLE APPROACH

    Institute of Scientific and Technical Information of China (English)

    Wei GE; Jinghai LI

    2005-01-01

    The multi-scale structures of complex flows in chemical engineering have been great challenges to the design and scaling of such systems, and multi-scale modeling is the natural way in response. Particle methods (PMs) are ideal constituents and powerful tools of multi-scale models, owing to their physical fidelity and computational simplicity. Especially,pseudo-particle modeling (PPM, Ge & Li, 1996; Ge & Li, 2003) is most suitable for molecular scale flow prediction and exploration of the origin of multi-scale structures; macro-scale PPM (MaPPM, Ge & Li, 2001) and similar models are advantageous for meso-scale simulations of flows with complex and dynamic discontinuity, while the lattice Boltzmann model is more competent for homogeneous media in complex geometries; and meso-scale methods such as dissipative particle dynamics are unique tools for complex fluids of uncertain properties or flows with strong thermal fluctuations. All these methods are favorable for seamless interconnection of models for different scales.However, as PMs are not originally designed as either tools for complexity or constituents of multi-scale models, further improvements are expected. PPM is proposed for microscopic simulation of particle-fluid systems as a combination of molecular dynamics (MD) and direct simulation Monte-Carlo (DSMC). The collision dynamics in PPM is identical to that of hard-sphere MD, so that mass, momentum and energy are conserved to machine accuracy. However, the collision detection procedure, which is most time-consuming and difficult to be parallelized for hard-sphere MD, has been greatly simplified to a procedure identical to that of soft-sphere MD. Actually, the physical model behind such a treatment is essentially different from MD and is more similar to DSMC, but an intrinsic difference is that in DSMC the collisions follow designed statistical rules that are reflection of the real physical processes only in very limited cases such as dilute gas.PPM is ideal

  7. Multi-agent based control of large-scale complex systems employing distributed dynamic inference engine

    Science.gov (United States)

    Zhang, Daili

    Increasing societal demand for automation has led to considerable efforts to control large-scale complex systems, especially in the area of autonomous intelligent control methods. The control system of a large-scale complex system needs to satisfy four system level requirements: robustness, flexibility, reusability, and scalability. Corresponding to the four system level requirements, there arise four major challenges. First, it is difficult to get accurate and complete information. Second, the system may be physically highly distributed. Third, the system evolves very quickly. Fourth, emergent global behaviors of the system can be caused by small disturbances at the component level. The Multi-Agent Based Control (MABC) method as an implementation of distributed intelligent control has been the focus of research since the 1970s, in an effort to solve the above-mentioned problems in controlling large-scale complex systems. However, to the author's best knowledge, all MABC systems for large-scale complex systems with significant uncertainties are problem-specific and thus difficult to extend to other domains or larger systems. This situation is partly due to the control architecture of multiple agents being determined by agent to agent coupling and interaction mechanisms. Therefore, the research objective of this dissertation is to develop a comprehensive, generalized framework for the control system design of general large-scale complex systems with significant uncertainties, with the focus on distributed control architecture design and distributed inference engine design. A Hybrid Multi-Agent Based Control (HyMABC) architecture is proposed by combining hierarchical control architecture and module control architecture with logical replication rings. First, it decomposes a complex system hierarchically; second, it combines the components in the same level as a module, and then designs common interfaces for all of the components in the same module; third, replications

  8. Engineering orthogonality in supramolecular polymers: from simple scaffolds to complex materials.

    Science.gov (United States)

    Elacqua, Elizabeth; Lye, Diane S; Weck, Marcus

    2014-08-19

    template polymerizations to enhance the control afforded by ROMP. Main-chain-functionalized alternating block polymers based upon SCS-Pd(II) pincer-pyridine motifs were achieved through the combined exploitation of bimetallic initiators and supramolecularly functionalized terminators. Our initial design principles led to the successful fabrication of both main-chain- and side-chain-functionalized poly(norbornenes) via ROMP. Utilizing all of these techniques in concert led to engineering orthogonality while achieving complexity through the installation of multiple supramolecular motifs within the side chain, main chain, or both in our polymer systems. The exploitation and modification of design principles based upon functional ROMP initiators and terminators has resulted in the first synthesis of main-chain heterotelechelic polymers that self-assemble into A/B/C supramolecular triblock polymers composed of orthogonal cyanuric acid-Hamilton wedge and SCS-Pd(II) pincer-pyridine motifs. Furthermore, supramolecular A/B/A triblock copolymers were realized through the amalgamation of functionalized monomers, ROMP initiators, and terminators. To date, this ROMP-fabricated system represents the only known method to afford polymer main chains and side chains studded with orthogonal motifs. We end by discussing the impetus to attain functional materials via orthogonal self-assembly. Collectively, our studies suggest that combining covalent and noncovalent bonds in a well-defined and precise manner is an essential design element to achieve complex architectures. The results discussed in this Account illustrate the finesse associated with engineering orthogonal interactions within supramolecular systems and are considered essential steps toward developing complex biomimetic materials with high precision and fidelity.

  9. Synthesis and luminescent properties of a novel green-emitting Tb (Ⅲ) complex based on amino-modified fluorine silicone oil and isophorone diisocyanate

    Science.gov (United States)

    Hao, Haixia; Chu, Yang; Yu, Zhenjiang; Xie, Hongde; Seo, Hyo Jin

    2017-10-01

    The novel luminescent polymer-rare earth complexes, denoted as (PFSi-IPDI)-Tb(Ⅲ)-Phen, have been successfully synthesized and can be made into flexible films. Amino-modified fluorine silicone oil-isophorone diisocyanate (PFSi-IPDI) was used as the host macromolecular ligand, and 1, 10-Phenanthroline (Phen) as the secondary small-molecular co-ligand. The luminescent lanthanide complexes were characterized by fourier transform infrared (FITR), scanning electron microscope (SEM), thermogravimetric analysis (TGA). The luminescent properties were investigated through photoluminescence excitation (PLE) and emission (PL) spectroscopy. FTIR analysis verifies the successful preparation and integration of PFSi-IPDI to Tb3+. The comparatively uniform morphological structure can be observed in the images of SEM. The polymer-rare earth complexes display the typical luminescence emission peaks under the excitation wavelength of 330 nm. From the decay curve, the short lifetime (about 0.89 ms) is observed for (PFSi-IPDI)-Tb(Ⅲ)-Phen (0.6 mol/L). Moreover, these luminescent polymer-rare earth complexes possess superior thermal stability (T5 > 195 °C). All the interesting results suggest the potential application of the luminescent polymer-rare earth complexes in green-emitting luminescent materials under high temperature.

  10. Synthesis of New Silicon-linked Lanthanocene Complexes and Their High Catalytic Activity for Methyl Methacrylate Polymerization with Nanometric Sodium Hydride as Co-catalyst

    Institute of Scientific and Technical Information of China (English)

    谢小敏; 黄吉玲

    2005-01-01

    The synthesis and characterization of four new silicon-linked lanthanocene complexes with pendant phenyl groups on cyclopentadiene were reported. Based on the data of elemental analyses, MS and IR, the complexes were presumed to be unsolvated and dimeric complexes [Me2Si(C5H3CMe2C6H5)2LnC1]2 [Ln=Er (1), Gd (2), Sm (3), Dy (4)]. In conjunction with AlEt3 or sodium hydride as the co-catalyst, these complexes could efficiently catalyze the polymerization of methyl methacrylate (MMA). When the nanometric sodium hydride was used as a co-catalyst, the complexes were highly effective for the polymerization of MMA. At low temperature and in short time, in [MeESi(C5H3CMe2C6H5)2LnC1]2/NaH (nanometric) system, the polymer was obtained in more than 80% yield and the molecular weight was greater than 105. The activity reached that of organolanthanide hydride as a single-component catalyst. In ]MeESi(C5H3CMe2C6H5)2ErC1]2/Nail (nanometric) system, the effects of the molar ratio of MMA/catalyst and catalyst/co-catalyst, and the temperature on polymerization were studied.

  11. Enhanced Extraction of Silicon-Vacancy Centers Light Emission Using Bottom-Up Engineered Polycrystalline Diamond Photonic Crystal Slabs.

    Science.gov (United States)

    Ondič, Lukáš; Varga, Marian; Hruška, Karel; Fait, Jan; Kapusta, Peter

    2017-03-28

    Silicon vacancy (SiV) centers are optically active defects in diamond. The SiV centers, in contrast to nitrogen vacancy (NV) centers, possess narrow and efficient luminescence spectrum (centered at ≈738 nm) even at room temperature, which can be utilized for quantum photonics and sensing applications. However, most of light generated in diamond is trapped in the material due to the phenomenon of total internal reflection. In order to overcome this issue, we have prepared two-dimensional photonic crystal slabs from polycrystalline diamond thin layers with high density of SiV centers employing bottom-up growth on quartz templates. We have shown that the spectral overlap between the narrow light emission of the SiV centers and the leaky modes extracting the emission into almost vertical direction (where it can be easily detected) can be obtained by controlling the deposition time. More than 14-fold extraction enhancement of the SiV centers photoluminescence was achieved compared to an uncorrugated sample. Computer simulation confirmed that the extraction enhancement originates from the efficient light-matter interaction between light emitted from the SiV centers and the photonic crystal slab.

  12. “Designing Danger”: Complex Engineering by Violent Non-State Actors: Introduction to the Special Issue

    Directory of Open Access Journals (Sweden)

    Gary Ackerman

    2016-03-01

    Full Text Available This Special Issue of the Journal of Strategic Security (JSS presents the results of a series of case studies of prior efforts by VNSAs to engage in complex engineering tasks, in the hope of informing strategic assessments of the threat of VNSA exploitation of emerging technologies. One particular concern in international security lies at the nexus of violent non-state actors (VNSAs and sophisticated technologies. When it comes to the assessment of such threats, much of the analysis hinges upon being able to accurately judge the desire and capability of adversaries to successfully carry out complex engineering operations. Yet, the actual process of how and why VNSAs engage in these efforts and the determinants of their success or failure are understudied aspects, at least in terms of systematic comparison across actors, technologies and time periods. This special issue presents the results of a series of case studies of prior efforts by VNSAs to engage in complex engineering tasks, in the hope of informing strategic assessments of the threat of VNSA exploitation of emerging technologies. The introductory article defines a complex engineering effort, summarizes the existing literature on the topic and sets out the methodology and framing questions used in the case studies.

  13. Sea Water Quality Modeling in the Frame of a Building First Turn of a Hydraulic Engineering Complex

    Directory of Open Access Journals (Sweden)

    Igor G. Kantargi

    2012-05-01

    Full Text Available The article deals with an application of developed system-dynamic model of the coastal waters quality for an assessment of sea water quality in the frame of building 1 turn of a hydraulic engineering complex "Object" the Island Federation». The attention is paid to a coast site with a coastal protection constructions.

  14. Sequential Fluorescent Labeling Observation of Maxillary Sinus Augmentation by a Tissue-engineered Bone Complex in Canine Model

    Institute of Scientific and Technical Information of China (English)

    Xin-quan Jiang; Shao-yi Wang; Jun Zhao; Xiu-li Zhang; Zhi-yuan Zhang

    2009-01-01

    Aim To evaluate the effects of maxillary sinus floor elevation by a tissue-engineered bone complex of β-tricalcium phosphate (β-TCP) and autologous osteoblasts in dogs. Methodology Autologous osteoblasts from adult Beagle dogs were cultured in vitro. They were further combined with β-TCP to construct the tissue-engineered bone complex. 12 cases of maxillary sinus floor elevation surgery were made bilaterally in 6 animals and randomly repaired with the following 3 groups of materials: Group A (osteoblasts/β-TCP); Group B (β-TCP); Group C (autogenous bone) (n-4 per group). A polychrome sequential fluorescent labeling was performed post-operatively and the animals were sacrificed 24 weeks after operation for histological observation.Results Our results showed that autologous osteoblasts were successfully expanded and the osteoblastic phenoltypes were confirmed by ALP and Alizarin red staining. The cells could attach and proliferate well on the surface of the β-TCP scaffold. The fluorescent and histological observation showed that the tissue-engineered bone complex had an earlier mineralization and more bone formation inside the scaffold than β-TCP along or even autologous bone. It had also maximally maintained the elevated sinus height than both control groups. Conclusion Porous β-TCP has served as a good scaffold for autologous osteoblasts seeding. The tissue-engineered bone complex with β-TCP and autologous osteoblasts might be a better alternative to autologous bone for the clinical edentulous maxillary sinus augmentation.

  15. Optimal configuration for a finite high-temperature source heat engine cycle with the complex heat transfer law

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The optimal configuration of a heat engine operating between a finite high-temperature source and an infinite low-temperature reservoir is derived by using finite time thermodynamics based on a complex heat transfer law,including Newtonian heat transfer law,linear phenomenological heat transfer law,radiative heat transfer law,Dulong-Petit heat transfer law,generalized convective heat transfer law and generalized radiative heat transfer law,q ∝(△T n). In the engine model the only irreversibility of finite rate heat transfer is considered. The optimal relation between the power output and efficiency of the heat engine is also derived by using an equivalent temperature of the hot reservoir. The obtained results include those obtained in recent literature and can provide some theoretical guidance for the designs of practical engines.

  16. Optimal configuration for a finite high-temperature source heat engine cycle with the complex heat transfer law

    Institute of Scientific and Technical Information of China (English)

    LI Jun; CHEN LinGen; SUN FengRui

    2009-01-01

    The optimal configuration of a heat engine operating between a finite high-temperature source and an infinite low-temperature reservoir is derived by using finite time thermodynamics based on a complex heat transfer law, including Newtonian heat transfer law, linear phenomenological heat transfer law, radiative heat transfer law, Dulong-Petit heat transfer law, generalized convective heat transfer law and generalized radiative heat transfer law, q∝ (△Tn). In the engine model the only irreversibility of finite rate heat transfer is considered. The optimal relation between the power output and efficiency of the heat engine is also derived by using an equivalent temperature of the hot reservoir. The obtained re-sults include those obtained in recent literature and can provide some theoretical guidance for the de-signs of practical engines.

  17. A Framework of Working Across Disciplines in Early Design and R&D of Large Complex Engineered Systems

    Science.gov (United States)

    McGowan, Anna-Maria Rivas; Papalambros, Panos Y.; Baker, Wayne E.

    2015-01-01

    This paper examines four primary methods of working across disciplines during R&D and early design of large-scale complex engineered systems such as aerospace systems. A conceptualized framework, called the Combining System Elements framework, is presented to delineate several aspects of cross-discipline and system integration practice. The framework is derived from a theoretical and empirical analysis of current work practices in actual operational settings and is informed by theories from organization science and engineering. The explanatory framework may be used by teams to clarify assumptions and associated work practices, which may reduce ambiguity in understanding diverse approaches to early systems research, development and design. The framework also highlights that very different engineering results may be obtained depending on work practices, even when the goals for the engineered system are the same.

  18. Conceptual Design Automation: Abstraction complexity reduction by feasilisation and knowledge engineering

    NARCIS (Netherlands)

    Schut, E.J.

    2010-01-01

    In order to keep innovating, engineers are working more and more with engineering software, providing them a way to cut away their routine and repetitive activities. Computer aided design and simulation software are for instance considered standard tools in most engineering companies. Today, to

  19. Conceptual Design Automation: Abstraction complexity reduction by feasilisation and knowledge engineering

    NARCIS (Netherlands)

    Schut, E.J.

    2010-01-01

    In order to keep innovating, engineers are working more and more with engineering software, providing them a way to cut away their routine and repetitive activities. Computer aided design and simulation software are for instance considered standard tools in most engineering companies. Today, to solv

  20. Integrated silicon optoelectronics

    CERN Document Server

    Zimmermann, Horst

    2000-01-01

    'Integrated Silicon Optoelectronics'assembles optoelectronics and microelectronics The book concentrates on silicon as the major basis of modern semiconductor devices and circuits Starting from the basics of optical emission and absorption and from the device physics of photodetectors, the aspects of the integration of photodetectors in modern bipolar, CMOS, and BiCMOS technologies are discussed Detailed descriptions of fabrication technologies and applications of optoelectronic integrated circuits are included The book, furthermore, contains a review of the state of research on eagerly expected silicon light emitters In order to cover the topic of the book comprehensively, integrated waveguides, gratings, and optoelectronic power devices are included in addition Numerous elaborate illustrations promote an easy comprehension 'Integrated Silicon Optoelectronics'will be of value to engineers, physicists, and scientists in industry and at universities The book is also recommendable for graduate students speciali...

  1. Neuromorphic Silicon Photonics

    CERN Document Server

    Tait, Alexander N; de Lima, Thomas Ferreira; Wu, Allie X; Nahmias, Mitchell A; Shastri, Bhavin J; Prucnal, Paul R

    2016-01-01

    We report first observations of an integrated analog photonic network, in which connections are configured by microring weight banks, as well as the first use of electro-optic modulators as photonic neurons. A mathematical isomorphism between the silicon photonic circuit and a continuous neural model is demonstrated through dynamical bifurcation analysis. Exploiting this isomorphism, existing neural engineering tools can be adapted to silicon photonic information processing systems. A 49-node silicon photonic neural network programmed using a "neural compiler" is simulated and predicted to outperform a conventional approach 1,960-fold in a toy differential system emulation task. Photonic neural networks leveraging silicon photonic platforms could access new regimes of ultrafast information processing for radio, control, and scientific computing.

  2. Applying accelerator mass spectrometry for low-level detection of complex engineered nanoparticles in biological media.

    Science.gov (United States)

    Wang, Binghui; Jackson, George S; Yokel, Robert A; Grulke, Eric A

    2014-08-01

    Complex engineered nanoparticles (CENPs), which have different core and surface components, are being developed for medicinal, pharmaceutical and industrial applications. One of the key challenges for environmental health and safety assessments of CENPs is to identify and quantity their transformations in biological environments. This study reports the effects of in vivo exposure of citrate-coated nanoalumina with different rare isotope labels on each component. This CENP was dosed to the rat and accelerator mass spectrometry (AMS) was used to quantify (26)Al, (14)C, and their ratio in the dosing material and tissue samples. For CENPs detected in the liver, the rare isotope ratio, (14)C/(26)Al, was 87% of the dosing material's ratio. The citrate coating on the nanoalumina in the liver was stable or, if it degraded, its metabolites were incorporated with nearby tissues. However, in brain and bone where little alumina was detected, the rare isotope ratio greatly exceeded that of the dosing material. Therefore, in the animal, citrate dissociated from CENPs and redistributed to brain and bone. Tracking both the core and surface components by AMS presents a new approach for characterizing transformations of CENPs components in biological milieu or environments.

  3. High resolution characterization of engineered nanomaterial dispersions in complex media using tunable resistive pulse sensing technology.

    Science.gov (United States)

    Pal, Anoop K; Aalaei, Iraj; Gadde, Suresh; Gaines, Peter; Schmidt, Daniel; Demokritou, Philip; Bello, Dhimiter

    2014-09-23

    In vitro toxicity assessment of engineered nanomaterials (ENM), the most common testing platform for ENM, requires prior ENM dispersion, stabilization, and characterization in cell culture media. Dispersion inefficiencies and active aggregation of particles often result in polydisperse and multimodal particle size distributions. Accurate characterization of important properties of such polydisperse distributions (size distribution, effective density, charge, mobility, aggregation kinetics, etc.) is critical for understanding differences in the effective dose delivered to cells as a function of time and dispersion conditions, as well as for nano-bio interactions. Here we have investigated the utility of tunable nanopore resistive pulse sensing (TRPS) technology for characterization of four industry relevant ENMs (oxidized single-walled carbon nanohorns, carbon black, cerium oxide and nickel nanoparticles) in cell culture media containing serum. Harvard dispersion and dosimetry platform was used for preparing ENM dispersions and estimating delivered dose to cells based on dispersion characterization input from dynamic light scattering (DLS) and TRPS. The slopes of cell death vs administered and delivered ENM dose were then derived and compared. We investigated the impact of serum protein content, ENM concentration, and cell medium on the size distributions. The TRPS technology offers higher resolution and sensitivity compared to DLS and unique insights into ENM size distribution and concentration, as well as particle behavior and morphology in complex media. The in vitro dose-response slopes changed significantly for certain nanomaterials when delivered dose to cells was taken into consideration, highlighting the importance of accurate dispersion and dosimetry in in vitro nanotoxicology.

  4. The Design of Large-Scale Complex Engineered Systems: Present Challenges and Future Promise

    Science.gov (United States)

    Bloebaum, Christina L.; McGowan, Anna-Maria Rivas

    2012-01-01

    Model-Based Systems Engineering techniques are used in the SE community to address the need for managing the development of complex systems. A key feature of the MBSE approach is the use of a model to capture the requirements, architecture, behavior, operating environment and other key aspects of the system. The focus on the model differentiates MBSE from traditional SE techniques that may have a document centric approach. In an effort to assess the benefit of utilizing MBSE on its flight projects, NASA Langley has implemented a pilot program to apply MBSE techniques during the early phase of the Materials International Space Station Experiment-X (MISSE-X). MISSE-X is a Technology Demonstration Mission being developed by the NASA Office of the Chief Technologist i . Designed to be installed on the exterior of the International Space Station (ISS), MISSE-X will host experiments that advance the technology readiness of materials and devices needed for future space exploration. As a follow-on to the highly successful series of previous MISSE experiments on ISS, MISSE-X benefits from a significant interest by the

  5. Modeling conically scanning lidar error in complex terrain with WAsP Engineering

    Energy Technology Data Exchange (ETDEWEB)

    Bingoel, F.; Mann, J.; Foussekis, D.

    2008-11-15

    Conically scanning lidars assume the flow to be homogeneous in order to deduce the horizontal wind speed. However, in mountainous or complex terrain this assumption is not valid implying an erroneous wind speed. The magnitude of this error is measured by collocating a meteorological mast and a lidar at two Greek sites, one hilly and one mountainous. The maximum error for the sites investigated is of the order of 10%. In order to predict the error for various wind directions the flows at both sites are simulated with the linearized flow model, WAsP Engineering 2.0. The measurement data are compared with the model predictions with good results for the hilly site, but with less success at the mountainous site. This is a deficiency of the flow model, but the methods presented in this paper can be used with any flow model. An abbreviated version of this report has been submitted to Meteorologische Zeitschrift. This work is partly financed through the UPWIND project (WP6, D3) funded by the European Commission. (au)

  6. Ultracompact 160 Gbaud all-optical demultiplexing exploiting slow light in an engineered silicon photonic crystal waveguide.

    Science.gov (United States)

    Corcoran, Bill; Pelusi, Mark D; Monat, Christelle; Li, Juntao; O'Faolain, Liam; Krauss, Thomas F; Eggleton, Benjamin J

    2011-05-01

    We demonstrate all-optical demultiplexing of a high-bandwidth, time-division multiplexed 160 Gbit/s signal to 10 Gbit/s channels, exploiting slow light enhanced four-wave mixing in a dispersion engineered, 96 μm long planar photonic crystal waveguide. We report error-free (bit error rate<10⁻⁹) operation of all 16 demultiplexed channels, with a power penalty of 2.2-2.4 dB, highlighting the potential of these structures as a platform for ultracompact all-optical nonlinear processes.

  7. Understanding and engineering two-dimensional electron gases in complex oxides

    Science.gov (United States)

    Bjaalie, Lars Gunnar Tangen

    The next generation of electronic devices faces the challenge of adequately containing and controlling extremely high charge densities within structures of nanometer dimensions. Atomic-scale transistors must be thin and be able to control extremely high charge densities (>10e13/cm. 2). Silicon devicestypically have two-dimensional electron gas (2DEG) densities around 10e12/cm. 2.Nitride-based devices can sustain densities an order of magnitude higher. The "complex oxides" have recently emerged as an attractive materials system to support these developments. The demonstration of a 2DEG at the SrTiO 3/LaAlO3 interface has triggered an avalanche of research, including the unprecedentedly high density of 3x10e14/cm. 2 at SrTiO3/GdTiO3and SrTiO3/SmTiO3 interfaces. Metal-insulator (Mott) transitions that are inherent to some of these complex oxides could offer even greater prospects for enhanced functionality or novel device concepts. The materials and heterostructures that have been explored to date are clearly only a small subset of the vast number of materials combinations that could lead to interesting phenomena. In this work we use first-principles methods to build greater understanding of the interface phenomena, so that searches can be better informed and more focused. We also develop a set of criteria that the materials and their heterostructures should satisfy to develop a high-performance 2DEG-based device. We focus in particular on the band alignment, calculating it for a variety of different potential materials. Next, we study GdTiO3/SrTiO3/GdTiO3 heterostructures in depth, where each interface contributes excess electrons into the SrTiO3. We calculate the 2DEG formation for a superlattice containing six layers of SrTiO3, and compare with angle-resolved photoemission spectroscopy results. Together, the experimental and theoretical results conclusively show that the 2DEG results from the interface itself, and does not originate from a secondary source such as

  8. An atomistic vision of the Mass Action Law: Prediction of carbon/oxygen defects in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Brenet, G.; Timerkaeva, D.; Caliste, D.; Pochet, P. [CEA, INAC-SP2M, Atomistic Simulation Laboratory, F-38000 Grenoble (France); Univ. Grenoble Alpes, INAC-SP2M, L-Sim, F-38000 Grenoble (France); Sgourou, E. N.; Londos, C. A. [University of Athens, Solid State Physics Section, Panepistimiopolis Zografos, Athens 157 84 (Greece)

    2015-09-28

    We introduce an atomistic description of the kinetic Mass Action Law to predict concentrations of defects and complexes. We demonstrate in this paper that this approach accurately predicts carbon/oxygen related defect concentrations in silicon upon annealing. The model requires binding and migration energies of the impurities and complexes, here obtained from density functional theory (DFT) calculations. Vacancy-oxygen complex kinetics are studied as a model system during both isochronal and isothermal annealing. Results are in good agreement with experimental data, confirming the success of the methodology. More importantly, it gives access to the sequence of chain reactions by which oxygen and carbon related complexes are created in silicon. Beside the case of silicon, the understanding of such intricate reactions is a key to develop point defect engineering strategies to control defects and thus semiconductors properties.

  9. Semiconducting silicon nanowires for biomedical applications

    CERN Document Server

    Coffer, JL

    2014-01-01

    Biomedical applications have benefited greatly from the increasing interest and research into semiconducting silicon nanowires. Semiconducting Silicon Nanowires for Biomedical Applications reviews the fabrication, properties, and applications of this emerging material. The book begins by reviewing the basics, as well as the growth, characterization, biocompatibility, and surface modification, of semiconducting silicon nanowires. It goes on to focus on silicon nanowires for tissue engineering and delivery applications, including cellular binding and internalization, orthopedic tissue scaffol

  10. Engineering yeast consortia for surface-display of complex cellulosome structures

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wilfred [University of Delaware

    2014-03-31

    As our society marches toward a more technologically advanced future, energy and environmental sustainability are some of the most challenging problems we face today. Biomass is one of the most abundant renewable-feedstock for sustainable production of biofuels. However, the main technological obstacle to more widespread uses of this resource is the lack of low-cost technologies to overcome the recalcitrant nature of the cellulosic structure, especially the hydrolysis step on highly ordered celluloses. In this proposal, we successfully engineered several efficient and inexpensive whole-cell biocatalysts in an effort to produce economically compatible and sustainable biofuels, namely cellulosic ethanol. Our approach was to display of a highly efficient cellulolytic enzyme complex, named cellulosome, on the surface of a historical ethanol producer Saccharomyces cerevisiae for the simultaneous and synergistic saccharification and fermentation of cellulose to ethanol. We first demonstrated the feasibility of assembling a mini-cellulosome by incubating E. coli lysates expressing three different cellulases. Resting cells displaying mini-cellulosomes produced 4-fold more ethanol from phosphoric acid-swollen cellulose (PASC) than cultures with only added enzymes. The flexibility to assemble the mini-cellulosome structure was further demonstrated using a synthetic yeast consortium through intracellular complementation. Direct ethanol production from PASC was demonstrated with resting cell cultures. To create a microorganism suitable for a more cost-effective process, called consolidated bioprocessing (CBP), a synthetic consortium capable of displaying mini-cellulosomes on the cell surface via intercellular complementation was created. To further improve the efficiency, a new adaptive strategy of employing anchoring and adaptor scaffoldins to amplify the number of enzymatic subunits was developed, resulting in the creation of an artificial tetravalent cellulosome on the

  11. A 3D bioprinted complex structure for engineering the muscle-tendon unit.

    Science.gov (United States)

    Merceron, Tyler K; Burt, Morgan; Seol, Young-Joon; Kang, Hyun-Wook; Lee, Sang Jin; Yoo, James J; Atala, Anthony

    2015-06-17

    Three-dimensional integrated organ printing (IOP) technology seeks to fabricate tissue constructs that can mimic the structural and functional properties of native tissues. This technology is particularly useful for complex tissues such as those in the musculoskeletal system, which possess regional differences in cell types and mechanical properties. Here, we present the use of our IOP system for the processing and deposition of four different components for the fabrication of a single integrated muscle-tendon unit (MTU) construct. Thermoplastic polyurethane (PU) was co-printed with C2C12 cell-laden hydrogel-based bioink for elasticity and muscle development on one side, while poly(ϵ-caprolactone) (PCL) was co-printed with NIH/3T3 cell-laden hydrogel-based bioink for stiffness and tendon development on the other. The final construct was elastic on the PU-C2C12 muscle side (E = 0.39 ± 0.05 MPa), stiff on the PCL-NIH/3T3 tendon side (E = 46.67 ± 2.67 MPa) and intermediate in the interface region (E = 1.03 ± 0.14 MPa). These constructs exhibited >80% cell viability at 1 and 7 d after printing, as well as initial tissue development and differentiation. This study demonstrates the versatility of the IOP system to create integrated tissue constructs with region-specific biological and mechanical characteristics for MTU engineering.

  12. Next Generation Device Grade Silicon-Germanium on Insulator

    Science.gov (United States)

    Littlejohns, Callum G.; Nedeljkovic, Milos; Mallinson, Christopher F.; Watts, John F.; Mashanovich, Goran Z.; Reed, Graham T.; Gardes, Frederic Y.

    2015-02-01

    High quality single crystal silicon-germanium-on-insulator has the potential to facilitate the next generation of photonic and electronic devices. Using a rapid melt growth technique we engineer tailored single crystal silicon-germanium-on-insulator structures with near constant composition over large areas. The proposed structures avoid the problem of laterally graded SiGe compositions, caused by preferential Si rich solid formation, encountered in straight SiGe wires by providing radiating elements distributed along the structures. This method enables the fabrication of multiple single crystal silicon-germanium-on-insulator layers of different compositions, on the same Si wafer, using only a single deposition process and a single anneal process, simply by modifying the structural design and/or the anneal temperature. This facilitates a host of device designs, within a relatively simple growth environment, as compared to the complexities of other methods, and also offers flexibility in device designs within that growth environment.

  13. Finite-time exergoeconomic performance of a generalized irreversible Carnot heat engine with complex heat transfer law

    Directory of Open Access Journals (Sweden)

    Jun Li, Lingen Chen, Yanlin Ge, Fengrui Sun

    2015-01-01

    Full Text Available The finite time exergoeconomic performance of the generalized irreversible Carnot heat engine with the losses of heat resistance, heat leakage and internal irreversibility, and with a complex heat transfer law, including generalized convective heat transfer law and generalized radiative heat transfer law is investigated in this paper. The focus of this paper is to obtain the compromised optimization between economics (profit and the energy utilization factor (efficiency for the generalized irreversible Carnot heat engine, by searching the optimum efficiency at maximum profit, which is termed as the finite time exergoeconomic performance bound. The obtained results include those obtained in many literatures and can provide some theoretical guidelines for the design of practical heat engines.

  14. Envisioning engineering education and practice in the coming intelligence convergence era — a complex adaptive systems approach

    Science.gov (United States)

    Noor, Ahmed

    2013-12-01

    Some of the recent attempts for improving and transforming engineering education are reviewed. The attempts aim at providing the entry level engineers with the skills needed to address the challenges of future large-scale complex systems and projects. Some of the frontier sectors and future challenges for engineers are outlined. The major characteristics of the coming intelligence convergence era (the post-information age) are identified. These include the prevalence of smart devices and environments, the widespread applications of anticipatory computing and predictive / prescriptive analytics, as well as a symbiotic relationship between humans and machines. Devices and machines will be able to learn from, and with, humans in a natural collaborative way. The recent game changers in learnscapes (learning paradigms, technologies, platforms, spaces, and environments) that can significantly impact engineering education in the coming era are identified. Among these are open educational resources, knowledge-rich classrooms, immersive interactive 3D learning, augmented reality, reverse instruction / flipped classroom, gamification, robots in the classroom, and adaptive personalized learning. Significant transformative changes in, and mass customization of, learning are envisioned to emerge from the synergistic combination of the game changers and other technologies. The realization of the aforementioned vision requires the development of a new multidisciplinary framework of emergent engineering for relating innovation, complexity and cybernetics, within the future learning environments. The framework can be used to treat engineering education as a complex adaptive system, with dynamically interacting and communicating components (instructors, individual, small, and large groups of learners). The emergent behavior resulting from the interactions can produce progressively better, and continuously improving, learning environment. As a first step towards the realization of

  15. Forward current enhanced elimination of the radiation induced boron-oxygen complex in silicon n+-p diodes

    CERN Document Server

    Makarenko, L F; Yakushevich, H S; Moll, M; Pintilie, I

    2014-01-01

    Using forward current injection with densities in the range 15-30A/cm(2) we can effectively eliminate the radiation-induced boron-oxygen complex, which is the main compensating center in irradiated Si solar cells. It was found that for a given forward current density the elimination rate is decreasing with increasing irradiation dose. Additionally, some evidences have been obtained on the negative-U properties of the radiation-induced boron-oxygen complex.

  16. Synthesis and structural characterization of hexacoordinate silicon, germanium, and titanium complexes of the E. coli siderophore enterobactin.

    Science.gov (United States)

    Baramov, Todor; Keijzer, Karlijn; Irran, Elisabeth; Mösker, Eva; Baik, Mu-Hyun; Süssmuth, Roderich

    2013-08-01

    The E. coli siderophore enterobactin, one of the strongest Fe(III) chelators known to date, is also capable of binding Si(IV) under physiological conditions. We report on the synthesis and structural characterization of the tris(catecholate) Si(IV) -enterobactin complex and its Ge(IV) and Ti(IV) analogues. Comparative structural analysis, supported by quantum-chemical calculations, reveals the correlation between the ionic radius and the structural changes in enterobactin upon complexation.

  17. Kinetics of the permanent deactivation of the boron-oxygen complex in crystalline silicon as a function of illumination intensity

    Science.gov (United States)

    Steckenreiter, Verena; Walter, Dominic C.; Schmidt, Jan

    2017-03-01

    Based on contactless carrier lifetime measurements performed on p-type boron-doped Czochralski-grown silicon (Cz-Si) wafers, we examine the rate constant Rde of the permanent deactivation process of the boron-oxygen-related defect center as a function of the illumination intensity I at 170°C. While at low illumination intensities, a linear increase of Rde on I is measured, at high illumination intensities, Rde seems to saturate. We are able to explain the saturation by assuming that Rde increases proportionally with the excess carrier concentration Δ n and take the fact into account that at sufficiently high illumination intensities, the carrier lifetime decreases with increasing Δ n and hence the slope of Δ n (I) decreases, leading to an apparent saturation. Importantly, on low-lifetime Cz-Si samples no saturation of the deactivation rate constant is observed for the same illumination intensities, proving that the deactivation is stimulated by the presence of excess electrons and not directly by the photons.

  18. Potentiometric surfaces of the Arnold Engineering Development Complex Area, Arnold Air Force Base, Tennessee, May and September 2011

    Science.gov (United States)

    Haugh, Connor J.; Robinson, John A.

    2016-01-29

    Arnold Air Force Base occupies about 40,000 acres in Coffee and Franklin Counties, Tennessee. The primary mission of Arnold Air Force Base is to provide risk-reduction information in the development of aerospace products through test and evaluation. This mission is achieved in part through test facilities at Arnold Engineering Development Complex (AEDC), which occupies about 4,000 acres in the center of Arnold Air Force Base. Arnold Air Force Base is underlain by gravel and limestone aquifers, the most productive of which is the Manchester aquifer. Several volatile organic compounds, primarily chlorinated solvents, have been identified in the groundwater at Arnold Air Force Base. In 2011, the U.S. Geological Survey, in cooperation with the U.S. Air Force, Arnold Air Force Base, completed a study of groundwater flow focused on the Arnold Engineering Development Complex area. The Arnold Engineering Development Complex area is of particular concern because within this area (1) chlorinated solvents have been identified in the groundwater, (2) the aquifers are dewatered around below-grade test facilities, and (3) there is a regional groundwater divide.

  19. Silicon microfabricated beam expander

    Science.gov (United States)

    Othman, A.; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A.; Ain, M. F.

    2015-03-01

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.

  20. Silicon microfabricated beam expander

    Energy Technology Data Exchange (ETDEWEB)

    Othman, A., E-mail: aliman@ppinang.uitm.edu.my; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A. [Faculty of Electrical Engineering, Universiti Teknologi MARA Malaysia, 40450, Shah Alam, Selangor (Malaysia); Ain, M. F. [School of Electrical and Electronic Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300,Nibong Tebal, Pulau Pinang (Malaysia)

    2015-03-30

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.

  1. Fiscal 1997 project on the R and D of industrial scientific technology under consignment from NEDO. Report on the results of the R and D of silicon-based polymeric materials (development of liquid methane fueled aircraft engine); 1997 nendo sangyo kagaku gijutsu kenkyu kaihatsu jigyo / Shin energy Sangyo gijutsu Sogo Kaihatsu Kiko itaku. Keisokei kobunshi zairyo no kenkyu kaihatsu (methane nenryo kokukiyo engine kaihatsu) seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    This R and D aims at establishing the basic technology on the molecular design, synthesis, use as materials, and evaluation of silicon-based polymers, of which excellent electronic/optical functions, high heat-resistance/combustion-resistance/dynamic characteristic are expected. The paper introduced the results of the fiscal 1997 R and D of them. The themes are as follows: technology of synthesis of silicon-based polymeric materials with sea-island microstructures, interstitial type structure forming technology, composite materials with organometallic complexes and silicon-based polymers, silicon-based polymer structural materials with ring structures, optimization of the Wurtz`s synthesis method of silicon-based polymers, unsaturated and hypercoordinate organosilicic compounds, function of silicon-based polymers, synthesis and polymerization of new silicon-based monomers, development of a new synthesis method of polysilane and the function, development of new application of silicon-based polymers in imaging devices for recording/memory/display of information, molecular design of {pi}-conjugate and {sigma}-conjugate compounds including silicon, and conformation and electronic state of silicon-based polymeric materials. 186 refs., 141 figs., 68 tabs.

  2. Complex effects of ecosystem engineer loss on benthic ecosystem response to detrital macroalgae

    NARCIS (Netherlands)

    Rossi, F.; Gribsholt, B.; Gazeau, F.; Di Santo, V.; Middelburg, J.J.

    2013-01-01

    Ecosystem engineers change abiotic conditions, community assembly and ecosystem functioning. Consequently, their loss may modify thresholds of ecosystem response to disturbance and undermine ecosystem stability. This study investigates how loss of the bioturbating lugworm Arenicola marina modifies t

  3. Complex Effects of Ecosystem Engineer Loss on Benthic Ecosystem Response to Detrital Macroalgae

    NARCIS (Netherlands)

    Rossi, F.; Gribsholt, B.; Gazeau, F.; Di Santo, V.; Middelburg, J.J.

    2013-01-01

    Ecosystem engineers change abiotic conditions, community assembly and ecosystem functioning. Consequently, their loss may modify thresholds of ecosystem response to disturbance and undermine ecosystem stability. This study investigates how loss of the bioturbating lugworm Arenicola marina modifies t

  4. Silicon applications in photonics

    Science.gov (United States)

    Jelenski, A. M.; Gawlik, G.; Wesolowski, M.

    2005-09-01

    Silicon technology enabled the miniaturization of computers and other electronic system for information storage, transmission and transformation allowing the development of the Knowledge Based Information Society. Despite the fact that silicon roadmap indicates possibilities for further improvement, already now the speed of electrons and the bandwidth of electronic circuits are not sufficient and photons are commonly utilized for signal transmission through optical fibers and purely photonic circuits promise further improvements. However materials used for these purposes II/V semiconductor compounds, glasses make integration of optoelectronic circuits with silicon complex an expensive. Therefore research on light generation, transformation and transmission in silicon is very active and recently, due to nanotechnology some spectacular results were achieved despite the fact that mechanisms of light generation are still discussed. Three topics will be discussed. Porous silicon was actively investigated due to its relatively efficient electroluminescence enabling its use in light sources. Its index of refraction, differs considerably from the index of silicon, and this allows its utilization for Bragg mirrors, wave guides and photonic crystals. The enormous surface enables several applications on medicine and biotechnology and in particular due to the effective chemo-modulation of its refracting index the design of optical chemosensors. An effective luminescence of doped and undoped nanocrystalline silicon opened another way for the construction of silicon light sources. Optical amplification was already discovered opening perspectives for the construction of nanosilicon lasers. Luminescences was observed at red, green and blue wavelengths. The used technology of silica and ion implantation are compatible with commonly used CMOS technology. Finally the recently developed and proved idea of optically pumped silicon Raman lasers, using nonlinearity and vibrations in the

  5. Innovative development problems of private sector of engineering and defense industrial complexes

    Directory of Open Access Journals (Sweden)

    A. V. Lugovtsov

    2010-09-01

    Full Text Available The innovation processes in non-governmental sector of machine building complex and defense industry complex of the Russian Federation are analyzed in this article. Also the recommendations for development are given.

  6. Cognitive engineering models: A prerequisite to the design of human-computer interaction in complex dynamic systems

    Science.gov (United States)

    Mitchell, Christine M.

    1993-01-01

    This chapter examines a class of human-computer interaction applications, specifically the design of human-computer interaction for the operators of complex systems. Such systems include space systems (e.g., manned systems such as the Shuttle or space station, and unmanned systems such as NASA scientific satellites), aviation systems (e.g., the flight deck of 'glass cockpit' airplanes or air traffic control) and industrial systems (e.g., power plants, telephone networks, and sophisticated, e.g., 'lights out,' manufacturing facilities). The main body of human-computer interaction (HCI) research complements but does not directly address the primary issues involved in human-computer interaction design for operators of complex systems. Interfaces to complex systems are somewhat special. The 'user' in such systems - i.e., the human operator responsible for safe and effective system operation - is highly skilled, someone who in human-machine systems engineering is sometimes characterized as 'well trained, well motivated'. The 'job' or task context is paramount and, thus, human-computer interaction is subordinate to human job interaction. The design of human interaction with complex systems, i.e., the design of human job interaction, is sometimes called cognitive engineering.

  7. Engineering the cell surface display of cohesins for assembly of cellulosome-inspired enzyme complexes on Lactococcus lactis

    Directory of Open Access Journals (Sweden)

    Wieczorek Andrew S

    2010-09-01

    Full Text Available Abstract Background The assembly and spatial organization of enzymes in naturally occurring multi-protein complexes is of paramount importance for the efficient degradation of complex polymers and biosynthesis of valuable products. The degradation of cellulose into fermentable sugars by Clostridium thermocellum is achieved by means of a multi-protein "cellulosome" complex. Assembled via dockerin-cohesin interactions, the cellulosome is associated with the cell surface during cellulose hydrolysis, forming ternary cellulose-enzyme-microbe complexes for enhanced activity and synergy. The assembly of recombinant cell surface displayed cellulosome-inspired complexes in surrogate microbes is highly desirable. The model organism Lactococcus lactis is of particular interest as it has been metabolically engineered to produce a variety of commodity chemicals including lactic acid and bioactive compounds, and can efficiently secrete an array of recombinant proteins and enzymes of varying sizes. Results Fragments of the scaffoldin protein CipA were functionally displayed on the cell surface of Lactococcus lactis. Scaffolds were engineered to contain a single cohesin module, two cohesin modules, one cohesin and a cellulose-binding module, or only a cellulose-binding module. Cell toxicity from over-expression of the proteins was circumvented by use of the nisA inducible promoter, and incorporation of the C-terminal anchor motif of the streptococcal M6 protein resulted in the successful surface-display of the scaffolds. The facilitated detection of successfully secreted scaffolds was achieved by fusion with the export-specific reporter staphylococcal nuclease (NucA. Scaffolds retained their ability to associate in vivo with an engineered hybrid reporter enzyme, E. coli β-glucuronidase fused to the type 1 dockerin motif of the cellulosomal enzyme CelS. Surface-anchored complexes exhibited dual enzyme activities (nuclease and β-glucuronidase, and were

  8. Deposited low temperature silicon GHz modulator

    CERN Document Server

    Lee, Yoon Ho Daniel; Lipson, Michal

    2013-01-01

    The majority of silicon photonics is built on silicon-on-insulator (SOI) wafers while the majority of electronics, including CPUs and memory, are built on bulk silicon wafers, limiting broader acceptance of silicon photonics. This discrepancy is a result of silicon photonics's requirement for a single-crystalline silicon (c-Si) layer and a thick undercladding for optical guiding that bulk silicon wafers to not provide. While the undercladding problem can be partially addressed by substrate removal techniques, the complexity of co-integrating photonics with state-of-the-art transistors and real estate competition between electronics and photonics remain problematic. We show here a platform for deposited GHz silicon photonics based on polycrystalline silicon with high optical quality suitable for high performance electro-optic devices. We demonstrate 3 Gbps polysilicon electro-optic modulator fabricated on a deposited polysilicon layer fully compatible with CMOS backend integration. These results open up an arr...

  9. Integrated Silicon Optoelectronics

    CERN Document Server

    Zimmermann, Horst K

    2010-01-01

    Integrated Silicon Optoelectronics synthesizes topics from optoelectronics and microelectronics. The book concentrates on silicon as the major base of modern semiconductor devices and circuits. Starting from the basics of optical emission and absorption, as well as from the device physics of photodetectors, the aspects of the integration of photodetectors in modern bipolar, CMOS, and BiCMOS technologies are discussed. Detailed descriptions of fabrication technologies and applications of optoelectronic integrated circuits are included. The book, furthermore, contains a review of the newest state of research on eagerly anticipated silicon light emitters. In order to cover the topics comprehensively, also included are integrated waveguides, gratings, and optoelectronic power devices. Numerous elaborate illustrations facilitate and enhance comprehension. This extended edition will be of value to engineers, physicists, and scientists in industry and at universities. The book is also recommended to graduate student...

  10. General algebraic method applied to control analysis of complex engine types

    Science.gov (United States)

    Boksenbom, Aaron S; Hood, Richard

    1950-01-01

    A general algebraic method of attack on the problem of controlling gas-turbine engines having any number of independent variables was utilized employing operational functions to describe the assumed linear characteristics for the engine, the control, and the other units in the system. Matrices were used to describe the various units of the system, to form a combined system showing all effects, and to form a single condensed matrix showing the principal effects. This method directly led to the conditions on the control system for noninteraction so that any setting disturbance would affect only its corresponding controlled variable. The response-action characteristics were expressed in terms of the control system and the engine characteristics. The ideal control-system characteristics were explicitly determined in terms of any desired response action.

  11. Formation and annealing of metastable (interstitial oxygen)-(interstitial carbon) complexes in n- and p-type silicon

    CERN Document Server

    Makarenko, L F; Lastovskii, S B; Murin, L I; Moll, M; Pintilie, I

    2014-01-01

    It is shown experimentally that, in contrast to the stable configuration of (interstitial carbon)-(interstitial oxygen) complexes (CiOi), the corresponding metastable configuration (CiOi{*}) cannot be found in n-Si based structures by the method of capacitance spectroscopy. The rates of transformation CiOi{*} -> CiOi are practically the same for both n- and p-Si with a concentration of charge carriers of no higher than 10(13) cm(-3). It is established that the probabilities of the simultaneous formation of stable and metastable configurations of the complex under study in the case of the addition of an atom of interstitial carbon to an atom of interstitial oxygen is close to 50\\%. This is caused by the orientation dependence of the interaction potential of an atom of interstitial oxygen with an interstitial carbon atom, which diffuses to this oxygen atom.

  12. A novel catalyst of silicon cerium complex oxides for selective catalytic reduction of NO by NH_3

    Institute of Scientific and Technical Information of China (English)

    徐海涛; 沈岳松; 邵成华; 林福文; 祝社民; 丘泰

    2010-01-01

    A series of CeO2/SiO2 and SixCe1-xO2 complex oxides supported on an activated Al2TiO5-TiO2-SiO2 complex phase (ATS) ceramics were prepared by step impregnation and co-impregnation methods, and characterized by N2-BET, XRD, SEM and NH3-TPD techniques. The effects of reaction temperature, CeO2/SiO2 loadings and Si/Ce molar ratio on the granular catalysts for NO selective catalytic reduction with ammonia (NH3-SCR) were studied. Results indicated that both CeO2/SiO2/ATS and CeO2/ATS catalysts showed the same ac...

  13. Alignment of Configuration and Documentation for Highly Engineered Complex Product Configuration Systems: a Demonstration from a Case Study

    DEFF Research Database (Denmark)

    Shafiee, Sara; Kristjansdottir, Katrin; Hvam, Lars

    2015-01-01

    Adequate documentation is critical for successful implementation, maintenance and further developments of product configuration system (PCS) specially in companies making complex and highly engineered products. This article is based on experience of modelling and utilizing a PCS from an Engineer......-To-Order (ETO), where the main focus is on the challenges concerned with the documentation of the PCS, both in the development and production phase. Aligning the development of the PCS with an automatic documentation system creates value. Using the suggested method for documentation facilitates the following...... activities: (1) iterative testing of the system during the development, (2) communication with domain experts, (3) documentation and maintenance, and finally (4) updates without spending a lot of time and resources. This article is supplemented with a case study from an ETO company where the method...

  14. Alignment of Configuration and Documentation for Highly Engineered Complex Product Configuration Systems: a Demonstration from a Case Study

    DEFF Research Database (Denmark)

    Shafiee, Sara; Kristjansdottir, Katrin; Hvam, Lars

    2015-01-01

    Adequate documentation is critical for successful implementation, maintenance and further developments of product configuration system (PCS) specially in companies making complex and highly engineered products. This article is based on experience of modelling and utilizing a PCS from an Engineer......-To-Order (ETO), where the main focus is on the challenges concerned with the documentation of the PCS, both in the development and production phase. Aligning the development of the PCS with an automatic documentation system creates value. Using the suggested method for documentation facilitates the following...... activities: (1) iterative testing of the system during the development, (2) communication with domain experts, (3) documentation and maintenance, and finally (4) updates without spending a lot of time and resources. This article is supplemented with a case study from an ETO company where the method...

  15. A business process modeling experience in a complex information system re-engineering.

    Science.gov (United States)

    Bernonville, Stéphanie; Vantourout, Corinne; Fendeler, Geneviève; Beuscart, Régis

    2013-01-01

    This article aims to share a business process modeling experience in a re-engineering project of a medical records department in a 2,965-bed hospital. It presents the modeling strategy, an extract of the results and the feedback experience.

  16. Using Social Media to Facilitate Knowledge Transfer in Complex Engineering Environments: A Primer for Educators

    Science.gov (United States)

    Murphy, Glen; Salomone, Sonia

    2013-01-01

    While highly cohesive groups are potentially advantageous they are also often correlated with the emergence of knowledge and information silos based around those same functional or occupational clusters. Consequently, an essential challenge for engineering organisations wishing to overcome informational silos is to implement mechanisms that…

  17. Photochemistry of Cobalt Carbonyl Complexes having a Cobalt-Silicon Bond and its Importance in Activation of Catalysis.

    Science.gov (United States)

    1980-08-22

    5 equation (4). These complexes are Co2 (CO)8 + 2HSiR 3 - 2R3SiCo(CO)4 + H2 (4) R = Et, Ph thermally inert at 250C in deoxygenated hydrocarbon...of Ph3SiCo(CO)4 in the presence of HSiEt 3only (a) and HSiEt 3 and P(OPh) 3 (b). Irradiation of the 25C deoxygenated solutions is at 355 nm (+ 20 nm...North Quincy Street P.O. Fox 1211 Arlington, Virginia 22217 2 Research Triangle Park, N.C. 27709 1 ONR Branch Office Naval Ocean Systems Center Attn

  18. Engineering and Sizing Nanoreactors To Confine Metal Complexes for Enhanced Catalytic Performance

    NARCIS (Netherlands)

    Shakeri, Mozaffar; Roiban, Lucian; Yazerski, Vital; Prieto Gonzalez, Gonzalo; Klein Gebbink, Bert; de Jongh, Petra E.; de Jong, Krijn P.

    2014-01-01

    Homogeneous metal complexes often display superior activity and selectivity in catalysis of chemical transformations. Heterogenization of these complexes by immobilization on solid supports has been used to facilitate recovery, but this is often associated with a decrease in catalytic performance. W

  19. On nanostructured silicon success

    DEFF Research Database (Denmark)

    Sigmund, Ole; Jensen, Jakob Søndergaard; Frandsen, Lars Hagedorn

    2016-01-01

    Recent Letters by Piggott et al. 1 and Shen et al. 2 claim the smallest ever dielectric wave length and polarization splitters. The associated News & Views article by Aydin3 states that these works “are the first experimental demonstration of on-chip, silicon photonic components based on complex...

  20. Engineering metal complexes of chiral pentaazacrowns as privileged reverse-turn scaffolds.

    Science.gov (United States)

    Che, Ye; Brooks, Bernard R; Riley, Dennis P; Reaka, Andrea J H; Marshall, Garland R

    2007-02-01

    Reverse turns are common structural motifs and recognition sites in protein/protein interactions. The design of peptidomimetics is often based on replacing the amide backbone of peptides by a non-peptidic scaffold while retaining the biologic mode of action. This study evaluates the potential of metal complexes of chiral pentaazacrowns conceptually derived by reduction of cyclic pentapeptides as reverse-turn mimetics. The possible conformations of metal complexes of chiral pentaazacrown scaffolds have been probed by analysis of 28 crystal structures complexed with six different metals (Mn, Fe, Co, Ni, Cu, and Zn). The solvated structures as well as the impact of complexation with different metals/oxidation states have been examined with density functional theory (DFT) calculation as explicitly represented by interactions with a single water molecule. The results suggest that most reverse-turn motifs seen in proteins could be mimicked effectively with a subset of metal complexes of chiral pentaazacrown scaffolds with an RMSD of approximately 0.3 A. Due to the relatively fixed orientation of the pendant chiral side groups in these metal complexes, one can potentially elicit information about the receptor-bound conformation of the parent peptide from their binding affinities. The presence of 20 H-atoms on the pentaazacrown ring that could be functionalized as well as the conformational perturbations available from complexation with different metals offer a desirable diversity to probe receptors for reverse-turn recognition.

  1. A model-based approach to associate complexity and robustness in engineering systems

    DEFF Research Database (Denmark)

    Göhler, Simon Moritz; D. Frey, Daniel; Howard, Thomas J.

    2017-01-01

    Ever increasing functionality and complexity of products and systems challenge development companies in achieving high and consistent quality. A model-based approach is used to investigate the relationship between system complexity and system robustness. The measure for complexity is based......-is-best requirements, the robustness is most affected by the level of contradiction between coupled functional requirements (p = 1.4e−36). In practice, the results imply that if the main influencing factors for each function in a system are known in the concept phase, an evaluation of the contradiction level can...

  2. Analysis of complex decisionmaking processes. [with application to jet engine development

    Science.gov (United States)

    Hill, J. D.; Ollila, R. G.

    1978-01-01

    The analysis of corporate decisionmaking processes related to major system developments is unusually difficult because of the number of decisionmakers involved in the process and the long development cycle. A method for analyzing such decision processes is developed and illustrated through its application to the analysis of the commercial jet engine development process. The method uses interaction matrices as the key tool for structuring the problem, recording data, and analyzing the data to establish the rank order of the major factors affecting development decisions. In the example, the use of interaction matrices permitted analysts to collect and analyze approximately 50 factors that influenced decisions during the four phases of the development cycle, and to determine the key influencers of decisions at each development phase. The results of this study indicate that the cost of new technology installed on an aircraft is the prime concern of the engine manufacturer.

  3. Silicon production process evaluations

    Science.gov (United States)

    1982-01-01

    Chemical engineering analyses involving the preliminary process design of a plant (1,000 metric tons/year capacity) to produce silicon via the technology under consideration were accomplished. Major activities in the chemical engineering analyses included base case conditions, reaction chemistry, process flowsheet, material balance, energy balance, property data, equipment design, major equipment list, production labor and forward for economic analysis. The process design package provided detailed data for raw materials, utilities, major process equipment and production labor requirements necessary for polysilicon production in each process.

  4. Development and Use of Engineering Standards for Computational Fluid Dynamics for Complex Aerospace Systems

    Science.gov (United States)

    Lee, Hyung B.; Ghia, Urmila; Bayyuk, Sami; Oberkampf, William L.; Roy, Christopher J.; Benek, John A.; Rumsey, Christopher L.; Powers, Joseph M.; Bush, Robert H.; Mani, Mortaza

    2016-01-01

    Computational fluid dynamics (CFD) and other advanced modeling and simulation (M&S) methods are increasingly relied on for predictive performance, reliability and safety of engineering systems. Analysts, designers, decision makers, and project managers, who must depend on simulation, need practical techniques and methods for assessing simulation credibility. The AIAA Guide for Verification and Validation of Computational Fluid Dynamics Simulations (AIAA G-077-1998 (2002)), originally published in 1998, was the first engineering standards document available to the engineering community for verification and validation (V&V) of simulations. Much progress has been made in these areas since 1998. The AIAA Committee on Standards for CFD is currently updating this Guide to incorporate in it the important developments that have taken place in V&V concepts, methods, and practices, particularly with regard to the broader context of predictive capability and uncertainty quantification (UQ) methods and approaches. This paper will provide an overview of the changes and extensions currently underway to update the AIAA Guide. Specifically, a framework for predictive capability will be described for incorporating a wide range of error and uncertainty sources identified during the modeling, verification, and validation processes, with the goal of estimating the total prediction uncertainty of the simulation. The Guide's goal is to provide a foundation for understanding and addressing major issues and concepts in predictive CFD. However, this Guide will not recommend specific approaches in these areas as the field is rapidly evolving. It is hoped that the guidelines provided in this paper, and explained in more detail in the Guide, will aid in the research, development, and use of CFD in engineering decision-making.

  5. A surface code quantum computer in silicon.

    Science.gov (United States)

    Hill, Charles D; Peretz, Eldad; Hile, Samuel J; House, Matthew G; Fuechsle, Martin; Rogge, Sven; Simmons, Michelle Y; Hollenberg, Lloyd C L

    2015-10-01

    The exceptionally long quantum coherence times of phosphorus donor nuclear spin qubits in silicon, coupled with the proven scalability of silicon-based nano-electronics, make them attractive candidates for large-scale quantum computing. However, the high threshold of topological quantum error correction can only be captured in a two-dimensional array of qubits operating synchronously and in parallel-posing formidable fabrication and control challenges. We present an architecture that addresses these problems through a novel shared-control paradigm that is particularly suited to the natural uniformity of the phosphorus donor nuclear spin qubit states and electronic confinement. The architecture comprises a two-dimensional lattice of donor qubits sandwiched between two vertically separated control layers forming a mutually perpendicular crisscross gate array. Shared-control lines facilitate loading/unloading of single electrons to specific donors, thereby activating multiple qubits in parallel across the array on which the required operations for surface code quantum error correction are carried out by global spin control. The complexities of independent qubit control, wave function engineering, and ad hoc quantum interconnects are explicitly avoided. With many of the basic elements of fabrication and control based on demonstrated techniques and with simulated quantum operation below the surface code error threshold, the architecture represents a new pathway for large-scale quantum information processing in silicon and potentially in other qubit systems where uniformity can be exploited.

  6. Complex composite engineering architectures for nuclear and high-radiation environments

    Energy Technology Data Exchange (ETDEWEB)

    Kornreich, Drew E [Los Alamos National Laboratory; Vaidya, Rajendra U [Los Alamos National Laboratory; Ammerman, Curtt N [Los Alamos National Laboratory

    2010-01-01

    Integrated Computational Materials Engineering (ICME) is a novel overarching approach to bridge length and time scales in computational materials science and engineering. This approach integrates all elements of multi-scale modeling (including various empirical and science-based models) with materials informatics to provide users the opportunity to tailor material selections based on stringent application needs. Typically, materials engineering has focused on structural requirements (stress, strain, modulus, fracture toughness etc.) while multi-scale modeling has been science focused (mechanical threshold strength model, grain-size models, solid-solution strengthening models etc.). Materials informatics (mechanical property inventories) on the other hand, is extensively data focused. All of these elements are combined within the framework of ICME to create architecture for the development, selection and design new composite materials for challenging environments. We propose development of the foundations for applying ICME to composite materials development for nuclear and high-radiation environments (including nuclear-fusion energy reactors, nuclear-fission reactors, and accelerators). We expect to combine all elements of current material models (including thermo-mechanical and finite-element models) into the ICME framework. This will be accomplished through the use of a various mathematical modeling constructs. These constructs will allow the integration of constituent models, which in tum would allow us to use the adaptive strengths of using a combinatorial scheme (fabrication and computational) for creating new composite materials. A sample problem where these concepts are used is provided in this summary.

  7. Embedded 3D Photopatterning of Hydrogels with Diverse and Complex Architectures for Tissue Engineering and Disease Models.

    Science.gov (United States)

    Davey, Shruti Krishna; Aung, Aereas; Agrawal, Gaurav; Lim, Han Liang; Kar, Mrityunjoy; Varghese, Shyni

    2015-11-01

    Techniques that can create three-dimensional (3D) structures to provide architectural support for cells have a significant impact in generating complex and hierarchically organized tissues/organs. In recent times, a number of technologies, including photopatterning, have been developed to create such intricate 3D structures. In this study, we describe an easy-to-implement photopatterning approach, involving a conventional fluorescent microscope and a simple photomask, to encapsulate cells within spatially defined 3D structures. We have demonstrated the ease and the versatility of this approach by creating simple to complex as well as multilayered structures. We have extended this photopatterning approach to incorporate and spatially organize multiple cell types, thereby establishing coculture systems. Such cost-effective and easy-to-use approaches can greatly advance tissue engineering strategies.

  8. Genetic Networks of Complex Disorders: from a Novel Search Engine for PubMed Article Database

    National Research Council Canada - National Science Library

    Jung, Jae-Yoon; Wall, Dennis Paul

    2013-01-01

    Finding genetic risk factors of complex disorders may involve reviewing hundreds of genes or thousands of research articles iteratively, but few tools have been available to facilitate this procedure...

  9. Silicon spintronics.

    Science.gov (United States)

    Jansen, Ron

    2012-04-23

    Worldwide efforts are underway to integrate semiconductors and magnetic materials, aiming to create a revolutionary and energy-efficient information technology in which digital data are encoded in the spin of electrons. Implementing spin functionality in silicon, the mainstream semiconductor, is vital to establish a spin-based electronics with potential to change information technology beyond imagination. Can silicon spintronics live up to the expectation? Remarkable advances in the creation and control of spin polarization in silicon suggest so. Here, I review the key developments and achievements, and describe the building blocks of silicon spintronics. Unexpected and puzzling results are discussed, and open issues and challenges identified. More surprises lie ahead as silicon spintronics comes of age.

  10. The Achievements and Challenges of Silicon Photonics

    Directory of Open Access Journals (Sweden)

    Richard Soref

    2008-01-01

    Full Text Available A brief overview of silicon photonics is given here in order to provide a context for invited and contributed papers in this special issue. Recent progress on silicon-based photonic components, photonic integrated circuits, and optoelectronic integrated circuits is surveyed. Present and potential applications are identified along with the scientific and engineering challenges that must be met in order to actualize applications. Some on-going government-sponsored projects in silicon optoelectronics are also described.

  11. A Complex E&S Model Considering 2D Vector Magnetic Properties of Silicon Steel Sheet%考虑硅钢片二维矢量磁特性的复数E&S模型

    Institute of Scientific and Technical Information of China (English)

    刘洋; 张艳丽; 谢德馨; 白保东; KOH Chang Seop

    2012-01-01

    The accurate modeling of electromagnetic characteristic of electric steel sheet has a significant effect on the magnetic field analysis and loss computation for electrical equipment. In this paper, a complex E&S magnetic properties model describing the 2D vector magnetic property of silicon steel sheet under both alternating magnetic field and rotating magnetic field was proposed. Based on 2D magnetic property measurement data, the effective magnetic reluctivity coefficients in this model were calculated according to average magnetic energy density in one time period, and the effective magnetic hysteresis coefficients were calculated from magnetic hysteresis loss density. The finite element analysis (FEA) combined with proposed magnetic property model was derived. Taking the ring iron core computation model as example, the effectiveness of the complex E&S model was compared with traditional E&S model. It is shown that the proposed model not only can save computing time but also can guarantee the accuracy of the calculation when combined with FEA, and is more suitable for engineering applications.%电工材料电磁特性的精细模拟是决定电工装备电磁场分析与损耗计算正确与否的关键因素之一。提出了一种能够描述硅钢片二维矢量磁特性的复数E&S模型,该模型既能够考虑交变磁化,又能够考虑旋转磁化的影响。基于硅钢片二维磁特性测量实验,提出了利用1个周期内磁能密度平均值计算模型中有效磁阻系数,利用磁滞损耗密度计算有效磁滞系数的方法。推导了结合复数E&S模型的磁场有限元分析公式,并以环形铁心模型为例,将复数E&S模型与传统E&S模型的计算结果进行了对比研究,指出复数E&S模型与有限元结合时既能够节省计算时间又能够保证材料特性模拟的准确性,是一种更适用于工程应用的矢量磁特性模型。

  12. Neutral penta- and hexacoordinate silicon(IV) complexes containing two bidentate ligands derived from the alpha-amino acids (S)-alanine, (S)-phenylalanine, and (S)-tert-leucine.

    Science.gov (United States)

    Cota, Smaranda; Beyer, Matthias; Bertermann, Rüdiger; Burschka, Christian; Götz, Kathrin; Kaupp, Martin; Tacke, Reinhold

    2010-06-11

    The neutral hexacoordinate silicon(IV) complex 6 (SiO(2)N(4) skeleton) and the neutral pentacoordinate silicon(IV) complexes 7-11 (SiO(2)N(2)C skeletons) were synthesized from Si(NCO)(4) and RSi(NCO)(3) (R = Me, Ph), respectively. The compounds were structurally characterized by solid-state NMR spectroscopy (6-11), solution NMR spectroscopy (6 and 10), and single-crystal X-ray diffraction (8 and 11 were studied as the solvates 8 x CH(3)CN and 11 x C(5)H(12) x 0.5 CH(3)CN, respectively). The silicon(IV) complexes 6 (octahedral Si-coordination polyhedron) and 7-11 (trigonal-bipyramidal Si-coordination polyhedra) each contain two bidentate ligands derived from an alpha-amino acid: (S)-alanine, (S)-phenylalanine, or (S)-tert-leucine. The deprotonated amino acids act as monoanionic (6) or as mono- and dianionic ligands (7-11). The experimental investigations were complemented by computational studies of the stereoisomers of 6 and 7.

  13. A model-based approach to associate complexity and robustness in engineering systems

    DEFF Research Database (Denmark)

    Göhler, Simon Moritz; D. Frey, Daniel; Howard, Thomas J.

    2017-01-01

    Ever increasing functionality and complexity of products and systems challenge development companies in achieving high and consistent quality. A model-based approach is used to investigate the relationship between system complexity and system robustness. The measure for complexity is based...... on the degree of functional coupling and the level of contradiction in the couplings. Whilst Suh’s independence axiom states that functional independence (uncoupled designs) produces more robust designs, this study proves this not to be the case for max-/min-is-best requirements, and only to be true......-is-best requirements, the robustness is most affected by the level of contradiction between coupled functional requirements (p = 1.4e−36). In practice, the results imply that if the main influencing factors for each function in a system are known in the concept phase, an evaluation of the contradiction level can...

  14. Highly Concentrated Alginate-Gellan Gum Composites for 3D Plotting of Complex Tissue Engineering Scaffolds

    Directory of Open Access Journals (Sweden)

    Ashwini Rahul Akkineni

    2016-04-01

    Full Text Available In tissue engineering, additive manufacturing (AM technologies have brought considerable progress as they allow the fabrication of three-dimensional (3D structures with defined architecture. 3D plotting is a versatile, extrusion-based AM technology suitable for processing a wide range of biomaterials including hydrogels. In this study, composites of highly concentrated alginate and gellan gum were prepared in order to combine the excellent printing properties of alginate with the favorable gelling characteristics of gellan gum. Mixtures of 16.7 wt % alginate and 2 or 3 wt % gellan gum were found applicable for 3D plotting. Characterization of the resulting composite scaffolds revealed an increased stiffness in the wet state (15%–20% higher Young’s modulus and significantly lower volume swelling in cell culture medium compared to pure alginate scaffolds (~10% vs. ~23%. Cytocompatibility experiments with human mesenchymal stem cells (hMSC revealed that cell attachment was improved—the seeding efficiency was ~2.5–3.5 times higher on the composites than on pure alginate. Additionally, the composites were shown to support hMSC proliferation and early osteogenic differentiation. In conclusion, print fidelity of highly concentrated alginate-gellan gum composites was comparable to those of pure alginate; after plotting and crosslinking, the scaffolds possessed improved qualities regarding shape fidelity, mechanical strength, and initial cell attachment making them attractive for tissue engineering applications.

  15. Silicon technologies ion implantation and thermal treatment

    CERN Document Server

    Baudrant, Annie

    2013-01-01

    The main purpose of this book is to remind new engineers in silicon foundry, the fundamental physical and chemical rules in major Front end treatments: oxidation, epitaxy, ion implantation and impurities diffusion.

  16. Multi and mixed 3D-printing of graphene-hydroxyapatite hybrid materials for complex tissue engineering.

    Science.gov (United States)

    Jakus, Adam E; Shah, Ramille N

    2017-01-01

    With the emergence of three-dimensional (3D)-printing (3DP) as a vital tool in tissue engineering and medicine, there is an ever growing need to develop new biomaterials that can be 3D-printed and also emulate the compositional, structural, and functional complexities of human tissues and organs. In this work, we probe the 3D-printable biomaterials spectrum by combining two recently established functional 3D-printable particle-laden biomaterial inks: one that contains hydroxyapatite microspheres (hyperelastic bone, HB) and another that contains graphene nanoflakes (3D-graphene, 3DG). We demonstrate that not only can these distinct, osteogenic, and neurogenic inks be co-3D-printed to create complex, multimaterial constructs, but that composite inks of HB and 3DG can also be synthesized. Specifically, the printability, microstructural, mechanical, electrical, and biological properties of a hybrid material comprised of 1:1 HA:graphene by volume is investigated. The resulting HB-3DG hybrid exhibits mixed characteristics of the two distinct systems, while maintaining 3D-printability, electrical conductivity, and flexibility. In vitro assessment of HB-3DG using mesenchymal stem cells demonstrates the hybrid material supports cell viability and proliferation, as well as significantly upregulates both osteogenic and neurogenic gene expression over 14 days. This work ultimately demonstrates a significant step forward towards being able to 3D-print graded, multicompositional, and multifunctional constructs from hybrid inks for complex composite tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 274-283, 2017. © 2016 Wiley Periodicals, Inc.

  17. Clinical efficacy and safety in head lice infection by Pediculus humanis capitis De Geer (Anoplura: Pediculidae of a capillary spray containing a silicon-oil complex*

    Directory of Open Access Journals (Sweden)

    Izri A.

    2010-12-01

    Full Text Available Head lice are endemic worldwide. Resistance to permethrin and doubts about the safety of pesticides promoted the use of physical therapies (wet-combing, dry-on suffocation. The aim of our study was to test the pediculicidal and ovicidal effects of one application of a silicon-oil complex composed of dimethiconol and castor oil. The study was a prospective cohort of 108 infested patients (11 males, 97 females; 58 children, 50 adults, in Sri-Lanka. Pediculicidal efficacy was evaluated as the percentage of patients free of live lice one hour after the application of the treatment and at day 1 (wet combing. Ovicidal efficacy was calculated as the proportion of subjects without larval stages at days 1 and 7 among subjects followed up all over the study. In normal conditions of use, in this open cohort, a pediculicidal effect of a dimethiconolcastor- oil lotion was shown one hour after application in 99/108 (91.7 % treated subjects and at day 1 in 86/99 (87 % subjects and an ovicidal effect at day 7 in 79/108 (73.2 % treated subjects. A second application of the same product was necessary to increase the cure rate to 79.6 % (86/108 at day 8. In our study, the second application of the same product was performed seven days later, but the best time for additional applications should be defined in further studies. However, the efficacy of this safe physical treatment was similar to that of chemical pediculicides (malathion, permethrin.

  18. Mortality of workers in an automobile engine and parts manufacturing complex.

    Science.gov (United States)

    Vena, J E; Sultz, H A; Fiedler, R C; Barnes, R E

    1985-01-01

    A proportionate mortality ratio (PMR) study was conducted using data on workers from three local unions representing an integrated automobile factory composed of forge, foundry, and engine (machine and assembly) plants. Ninety four percent of the death certificates were obtained for all active and non-active workers who died during the period 1 January 1970 to 31 December 1979 and were vested in union and company benefit programmes. Observed numbers of deaths were compared with expected numbers based on two standards, the proportionate mortality among men in the United States 1970-9 and among men in Erie County 1975. There was close agreement between the number of observed and expected deaths by either standard of comparison among white auto workers in the forge and foundry plants. Valid analyses of cause specific mortality among non-whites could be conducted for the foundry plant only. Although there was raised PMR for deaths due to diseases of the circulatory system using the Erie County standard, none of the other cause specific PMRs was significant. Although based on small numbers, the risk of cancer of the lung was significantly high in non-whites under age 50 in the foundry (PMR = 2.6; p less than 0.05). The cause specific PMRs for whites in the engine plant were statistically significant for malignant neoplasms (1.2) and all external causes (0.62) based on the US white male standard. Analysis of cancer specific mortality among white men in the machining/assembly plant showed significant excesses for cancer of the digestive system (PMR=1.5), particularly of the liver (PMR=2.6) and pancreas (PMR=1.9); cancers of the respiratory system (PMR=1.4 using the Erie County standard); and cancer of the urinary bladder (PMR=2.3). Workers employed for more than 20 years showed statistically increased mortality ratios for cancers of the digestive system (1.9), particularly cancer of the pancreas (2.3) and cancer of the rectum (2.8). Individuals whose employment began

  19. Next generation structural silicone glazing

    Directory of Open Access Journals (Sweden)

    Charles D. Clift

    2015-06-01

    Full Text Available This paper presents an advanced engineering evaluation, using nonlinear analysis of hyper elastic material that provides significant improvement to structural silicone glazing (SSG design in high performance curtain wall systems. Very high cladding wind pressures required in hurricane zones often result in bulky SSG profile dimensions. Architectural desire for aesthetically slender curtain wall framing sight-lines in combination with a desire to reduce aluminium usage led to optimization of silicone material geometry for better stress distribution.To accomplish accurate simulation of predicted behaviour under structural load, robust stress-strain curves of the silicone material are essential. The silicone manufacturer provided physical property testing via a specialized laboratory protocol. A series of rigorous curve fit techniques were then made to closely model test data in the finite element computer analysis that accounts for nonlinear strain of hyper elastic silicone.Comparison of this advanced design technique to traditional SSG design highlights differences in stress distribution contours in the silicone material. Simplified structural engineering per the traditional SSG design method does not provide accurate forecasting of material and stress optimization as shown in the advanced design.Full-scale specimens subject to structural load testing were performed to verify the design capacity, not only for high wind pressure values, but also for debris impact per ASTM E1886 and ASTM E1996. Also, construction of the test specimens allowed development of SSG installation techniques necessitated by the unique geometry of the silicone profile. Finally, correlation of physical test results with theoretical simulations is made, so evaluation of design confidence is possible. This design technique will introduce significant engineering advancement to the curtain wall industry.

  20. Aggradational and erosional history of the Radioactive Waste Management Complex at the Idaho National Engineering Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Dechert, T.V.; McDaniel, P.A.; Falen, A.L. [Idaho Univ., Moscow, ID (United States)

    1994-09-01

    Long-term performance of the low-level waste disposal site at the Radioactive Waste Management Complex (RWMC) is partially dependent on the stability of the land surface with respect to erosion of cover materials. This document discusses the aggradational and erosional history of the naturally occurring sediments and soils in and around the RWMC, focusing on the late-Pleistocene and Holocene epochs. Other related issues include the ages of the various deposits, the extent to which they have been altered by soil formation and other processes, their relationships to the basalt flows in the area, and the impact of human activity on the materials at the RWMC.

  1. Engineering complex nanolasers: from spaser quantum information sources to near-field anapole lasers

    KAUST Repository

    Gongora, J. S. Totero

    2017-02-16

    In this invited contribution I will review recent results of our research in the field of complex nanolasers. I will begin by discussing recent experimental results from a new type of ultra-dark nanoparticles, which behave as an ideal black-body and spontaneously produce single color pulses thanks to an equivalent Bose-Einstein Condensation of light. I will then discuss new quantum information sources from core-shell spaser nanoparticles. Finally, I will illustrate a new type of laser source that emits only in the near field, discussing applications in integrated optical circuits.

  2. Simple engineering design for complex thermoelectric generators based on reduced current approach

    DEFF Research Database (Denmark)

    Wijesooriyage, Waruna Dissanayaka; Rezaniakolaei, Alireza; Rosendahl, Lasse

    2015-01-01

    Thermoelectric generators (TEGs) are niche candidate for the field of energy management as electrical generator devices. Generally, comprehensive and accurate design techniques for TEGs (thermoelectric generators), such as reduced current approach (RCA), are complex and time consuming processes....... This study develops a simple, comprehensive and accurate TEG designing technique based on RCA. The proposed method can predict the most efficient TEG architecture with more than 97% accuracy comparing to the RCA over wide range of possible temperature and zT for present TEG applications. Moreover...

  3. Biodegradation of complex hydrocarbons in spent engine oil by novel bacterial consortium isolated from deep sea sediment.

    Science.gov (United States)

    Ganesh Kumar, A; Vijayakumar, Lakshmi; Joshi, Gajendra; Magesh Peter, D; Dharani, G; Kirubagaran, R

    2014-10-01

    Complex hydrocarbon and aromatic compounds degrading marine bacterial strains were isolated from deep sea sediment after enrichment on spent engine (SE) oil. Phenotypic characterization and phylogenetic analysis of 16S rRNA gene sequences showed the isolates were related to members of the Pseudoalteromonas sp., Ruegeria sp., Exiguobacterium sp. and Acinetobacter sp. Biodegradation using 1% (v/v) SE oil with individual and mixed strains showed the efficacy of SE oil utilization within a short retention time. The addition of non-ionic surfactant 0.05% (v/v) Tween 80 as emulsifying agent enhanced the solubility of hydrocarbons and renders them more accessible for biodegradation. The degradation of several compounds and the metabolites formed during the microbial oxidation process were confirmed by Fourier transform infrared spectroscopy and Gas chromatography-mass spectrometry analyses. The potential of this consortium to biodegrade SE oil with and without emulsifying agent provides possible application in bioremediation of oil contaminated marine environment.

  4. Crystal structure of I-DmoI in complex with its target DNA provides new insights into meganuclease engineering.

    Science.gov (United States)

    Marcaida, María José; Prieto, Jesús; Redondo, Pilar; Nadra, Alejandro D; Alibés, Andreu; Serrano, Luis; Grizot, Sylvestre; Duchateau, Philippe; Pâques, Frédéric; Blanco, Francisco J; Montoya, Guillermo

    2008-11-04

    Homing endonucleases, also known as meganucleases, are sequence-specific enzymes with large DNA recognition sites. These enzymes can be used to induce efficient homologous gene targeting in cells and plants, opening perspectives for genome engineering with applications in a wide series of fields, ranging from biotechnology to gene therapy. Here, we report the crystal structures at 2.0 and 2.1 A resolution of the I-DmoI meganuclease in complex with its substrate DNA before and after cleavage, providing snapshots of the catalytic process. Our study suggests that I-DmoI requires only 2 cations instead of 3 for DNA cleavage. The structure sheds light onto the basis of DNA binding, indicating key residues responsible for nonpalindromic target DNA recognition. In silico and in vivo analysis of the I-DmoI DNA cleavage specificity suggests that despite the relatively few protein-base contacts, I-DmoI is highly specific when compared with other meganucleases. Our data open the door toward the generation of custom endonucleases for targeted genome engineering using the monomeric I-DmoI scaffold.

  5. Wettability of Silicon with Refractory Materials: A Review

    OpenAIRE

    Ciftja, Arjan

    2008-01-01

    The wettability of ceramics by liquid metals is a key fac¬tor in many fields of high temperature materials science and engineering. The wetting behavior of liquid-silicon/refractory-materials system is especially important in refining and crystallization of silicon with respect to production of low cost solar cells but also in the production of silicon carbide based materials for advanced applications. This paper is a review on the wetting properties of molten silicon with various carbon, sil...

  6. Wettability of Silicon with Refractory Materials: A Review

    OpenAIRE

    Ciftja, Arjan

    2008-01-01

    The wettability of ceramics by liquid metals is a key fac¬tor in many fields of high temperature materials science and engineering. The wetting behavior of liquid-silicon/refractory-materials system is especially important in refining and crystallization of silicon with respect to production of low cost solar cells but also in the production of silicon carbide based materials for advanced applications. This paper is a review on the wetting properties of molten silicon with various carbon, sil...

  7. Interstitial-type defects in implanted silicon

    Energy Technology Data Exchange (ETDEWEB)

    Berezhnov, N.I.; Stel' makh, V.F.; Chelyadinskij, A.R.

    1984-07-01

    Boron-, lithium-, phosphorus- and silicon-implanted silicon layers were investigated using X-ray diffraction method for measuring the crystal lattice parameters. It was established that stable interstitial complexes in concentrations comparable with concentrations of vacancy type defects occur in silicon as a result of ion implantation. The interstitial complexes are annealed at the following stages: 1 - 140, 2 - 500 deg C in the case of silicon irradiation by light ions and 1 - 180, 2 - 560 deg C in crystals irradiated by medium mass ions.

  8. Addressing the complexity of water chemistry in environmental fate modeling for engineered nanoparticles.

    Science.gov (United States)

    Sani-Kast, Nicole; Scheringer, Martin; Slomberg, Danielle; Labille, Jérôme; Praetorius, Antonia; Ollivier, Patrick; Hungerbühler, Konrad

    2015-12-01

    Engineered nanoparticle (ENP) fate models developed to date - aimed at predicting ENP concentration in the aqueous environment - have limited applicability because they employ constant environmental conditions along the modeled system or a highly specific environmental representation; both approaches do not show the effects of spatial and/or temporal variability. To address this conceptual gap, we developed a novel modeling strategy that: 1) incorporates spatial variability in environmental conditions in an existing ENP fate model; and 2) analyzes the effect of a wide range of randomly sampled environmental conditions (representing variations in water chemistry). This approach was employed to investigate the transport of nano-TiO2 in the Lower Rhône River (France) under numerous sets of environmental conditions. The predicted spatial concentration profiles of nano-TiO2 were then grouped according to their similarity by using cluster analysis. The analysis resulted in a small number of clusters representing groups of spatial concentration profiles. All clusters show nano-TiO2 accumulation in the sediment layer, supporting results from previous studies. Analysis of the characteristic features of each cluster demonstrated a strong association between the water conditions in regions close to the ENP emission source and the cluster membership of the corresponding spatial concentration profiles. In particular, water compositions favoring heteroaggregation between the ENPs and suspended particulate matter resulted in clusters of low variability. These conditions are, therefore, reliable predictors of the eventual fate of the modeled ENPs. The conclusions from this study are also valid for ENP fate in other large river systems. Our results, therefore, shift the focus of future modeling and experimental research of ENP environmental fate to the water characteristic in regions near the expected ENP emission sources. Under conditions favoring heteroaggregation in these

  9. Alternative conformations of the Tau repeat domain in complex with an engineered binding protein.

    Science.gov (United States)

    Grüning, Clara S R; Mirecka, Ewa A; Klein, Antonia N; Mandelkow, Eckhard; Willbold, Dieter; Marino, Stephen F; Stoldt, Matthias; Hoyer, Wolfgang

    2014-08-15

    The aggregation of Tau into paired helical filaments is involved in the pathogenesis of several neurodegenerative diseases, including Alzheimer disease. The aggregation reaction is characterized by conformational conversion of the repeat domain, which partially adopts a cross-β-structure in the resulting amyloid-like fibrils. Here, we report the selection and characterization of an engineered binding protein, β-wrapin TP4, targeting the Tau repeat domain. TP4 was obtained by phage display using the four-repeat Tau construct K18ΔK280 as a target. TP4 binds K18ΔK280 as well as the longest isoform of human Tau, hTau40, with nanomolar affinity. NMR spectroscopy identified two alternative TP4-binding sites in the four-repeat domain, with each including two hexapeptide motifs with high β-sheet propensity. Both binding sites contain the aggregation-determining PHF6 hexapeptide within repeat 3. In addition, one binding site includes the PHF6* hexapeptide within repeat 2, whereas the other includes the corresponding hexapeptide Tau(337-342) within repeat 4, denoted PHF6**. Comparison of TP4-binding with Tau aggregation reveals that the same regions of Tau are involved in both processes. TP4 inhibits Tau aggregation at substoichiometric concentration, demonstrating that it interferes with aggregation nucleation. This study provides residue-level insight into the interaction of Tau with an aggregation inhibitor and highlights the structural flexibility of Tau. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. A systems engineering approach to manage the complexity in sustainable chemical product-process design

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    This paper provides a perspective on model-data based solution approaches for chemical product-process design, which consists of finding the identity of the candidate chemical product, designing the process that can sustainably manufacture it and verifying the performance of the product during...... framework can manage the complexity associated with product-process problems very efficiently. Three specific computer-aided tools (ICAS, Sustain-Pro and VPPDLab) have been presented and their applications to product-process design, highlighted....... application. The chemical product tree is potentially very large and a wide range of options exist for selecting the product to make, the raw material to use as well as the processing route to employ. It is shown that systematic computer-aided methods and tools integrated within a model-data based design...

  11. Systems Engineering Design Via Experimental Operation Research: Complex Organizational Metric for Programmatic Risk Environments (COMPRE)

    Science.gov (United States)

    Mog, Robert A.

    1999-01-01

    Unique and innovative graph theory, neural network, organizational modeling, and genetic algorithms are applied to the design and evolution of programmatic and organizational architectures. Graph theory representations of programs and organizations increase modeling capabilities and flexibility, while illuminating preferable programmatic/organizational design features. Treating programs and organizations as neural networks results in better system synthesis, and more robust data modeling. Organizational modeling using covariance structures enhances the determination of organizational risk factors. Genetic algorithms improve programmatic evolution characteristics, while shedding light on rulebase requirements for achieving specified technological readiness levels, given budget and schedule resources. This program of research improves the robustness and verifiability of systems synthesis tools, including the Complex Organizational Metric for Programmatic Risk Environments (COMPRE).

  12. Engineering RNA-protein complexes with different shapes for imaging and therapeutic applications.

    Science.gov (United States)

    Osada, Eriko; Suzuki, Yuki; Hidaka, Kumi; Ohno, Hirohisa; Sugiyama, Hiroshi; Endo, Masayuki; Saito, Hirohide

    2014-08-26

    Molecular machines composed of RNA–protein (RNP) complexes may expand the fields of molecular robotics, nanomedicine, and synthetic biology. However, constructing and directly visualizing a functional RNP nanostructure to detect and control living cell function remains a challenge. Here we show that RNP nanostructures with modular functions can be designed and visualized at single-RNP resolution in real time. The RNP structural images collected in solution through high-speed atomic force microscopy showed that a single RNP interaction induces a conformational change in the RNA scaffold, which supports the nanostructure formation designed. The specific RNP interaction also improved RNA nanostructure stability in a serum-containing buffer. We developed and visualized functional RNPs (e.g., to detect human cancer cells or knockdown target genes) by attaching a protein or RNA module to the same RNA scaffold of an optimal size. The synthetic RNP architecture may provide alternative materials to detect and control functions in target mammalian cells.

  13. 水利工程复合场模型及可视化技术研究%Complex Field Model and Visualization Technology for Water Conservancy Engineering

    Institute of Scientific and Technical Information of China (English)

    谢楠

    2012-01-01

    A conceptual framework of complex field model is proposed for water conservancy engineering. The paper took the typiea| natural objects and human objects concerned in the water conservancy engineering as concrete research objects. Through the research of the visualizing and processing the data sets in the complex field, the paper used three dimensional visualization technologies and classified-layered displaying technologies to construct the complex field model. The research is to promote the cognitive ability of the complex field models in water conservancy engineering and to help the engineers to design and analyz~ the water conservancy construction, which will promote the efficiency and quality of the water conservan- cy engineering.%根据水利工程“复合场”模型,以水利工程涉及的典型自然对象和人工对象为具体的研究对象,通过研究水利工程复合场中数据的三维可视化模型及处理技术,实现对水利工程复合场的形象、直观与逼真的显示,从而提高人们对水利工程复合场及其间关系复杂性的认知能力,辅助工程设计、分析与施工.

  14. Enhancing Carbon Fixation by Metabolic Engineering: A Model System of Complex Network Modulation

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Gregory Stephanopoulos

    2008-04-10

    In the first two years of this research we focused on the development of a DNA microarray for transcriptional studies in the photosynthetic organism Synechocystis and the elucidation of the metabolic pathway for biopolymer synthesis in this organism. In addition we also advanced the molecular biological tools for metabolic engineering of biopolymer synthesis in Synechocystis and initiated a series of physiological studies for the elucidation of the carbon fixing pathways and basic central carbon metabolism of these organisms. During the last two-year period we focused our attention on the continuation and completion of the last task, namely, the development of tools for basic investigations of the physiology of these cells through, primarily, the determination of their metabolic fluxes. The reason for this decision lies in the importance of fluxes as key indicators of physiology and the high level of information content they carry in terms of identifying rate limiting steps in a metabolic pathway. While flux determination is a well-advanced subject for heterotrophic organisms, for the case of autotrophic bacteria, like Synechocystis, some special challenges had to be overcome. These challenges stem mostly from the fact that if one uses {sup 13}C labeled CO{sub 2} for flux determination, the {sup 13}C label will mark, at steady state, all carbon atoms of all cellular metabolites, thus eliminating the necessary differentiation required for flux determination. This peculiarity of autotrophic organisms makes it imperative to carry out flux determination under transient conditions, something that had not been accomplished before. We are pleased to report that we have solved this problem and we are now able to determine fluxes in photosynthetic organisms from stable isotope labeling experiments followed by measurements of label enrichment in cellular metabolites using Gas Chromatography-Mass Spectrometry. We have conducted extensive simulations to test the method and

  15. The main goal of engineering geology for designing and construction complex structures in urban areas

    Directory of Open Access Journals (Sweden)

    Drago Ocepek

    2007-12-01

    Full Text Available Work for designing complex structures in urban areas consists of geological-geotechnical investigations and analysis of the quality of rocks, soft rocks and hard soils in the construction area. Urban areas limited the space for designing cutting slopes in stable inclination without reinforcement. In this paper will be presented designing and excavation works with different reinforcement of two different areas in Slovenia built of heterogeneous mixed hard to soft rock masses (Triassic dolomite, limestone and Eocene flysch sediments.Before the start of excavations work and after establishing the retaining measures, the analysis results are checked by monitoring. This monitoring will continue in the phase of exploitation of the objects. Since the cost of these additional investigations and precise analysis with monitoring (SIST - EN 7 - 2004 and measurements is negligible – in comparison with the costs of the permanent reinforcement – if variable conditions are not to intensive, we were able to reduce effectively the investment value of the object.

  16. Chapter 17 - Engineering cationic liposome siRNA complexes for in vitro and in vivo delivery.

    Science.gov (United States)

    Podesta, Jennifer E; Kostarelos, Kostas

    2009-01-01

    RNA interference, the sequence-specific silencing of gene expression by introduction of short interfering RNA (siRNA) is a powerful tool that that the potential to act as a therapeutic agent and the advantage of decreasing toxic effects on normal tissue sometimes seen with conventional treatments i.e. small molecule inhibitors. Naked, unmodified siRNA is poorly taken up by cells and is subject to degradation when exposed to blood proteins during systemic administration. It has also been shown to produce non-specific immune response as well as having the potential to generate 'off-target' effects. Therefore there is a requirement for a delivery system to not only protect the siRNA and facilitate its uptake, but additionally to offer the potential for targeted delivery with an aim of exploiting the high specificity afforded by RNA interference. Cationic liposomes are the most studied, non-viral delivery system used for nucleic acid delivery. As such, the use of cationic liposomes is promising for siRNA for delivery. Furthermore, polyethylene glycol (PEG) can be incorporated into the liposome formulation to create sterically stabilized or 'stealth' liposomes. Addition of PEG can reduce recognition by the reticuloendothelial system (RES) thereby prolonging circulation time. Here we describe a methodology for the complexation of siRNA with cationic liposomes and PEGylated liposomes using two protocols: mixing and encapsulation. Moreover, the different formulations are compared head to head to demonstrate their efficacy for gene silencing.

  17. ADVANCED COMPUTATIONALMETHODS FOR COMPLEX SIMULATION OF THERMAL PROCESSES IN POWER ENGINEERING

    Directory of Open Access Journals (Sweden)

    Risto V. Filkoski

    2007-04-01

    Full Text Available The overall frame and principal steps of complex numerical modelling of thermal processes in power boiler furnaces on pulverised coal with tangential disposition of the burners are presented in the paper. Computational fluid dynamics (CFD technique is used as a tool to perform comprehensive thermal analysis in two test cases. The methodology for creation of three-dimensional models of boiler furnaces is briefly described. Standard steady k- model is employed for description of the turbulent flow. The coupling of continuity and momentum is achieved by the SIMPLEC method. Coal combustion is modelled by the mixture fraction/probability density function approach for the reaction chemistry, with equilibrium assumption applied for description of the system chemistry. Thermal radiation is computed by means of the simplified P-N model, based on expansion of the radiation intensity into an orthogonal series of spherical harmonics.Comparison between the simulation predictions and available site measurements leads to a conclusion that the model produces realistic insight into the furnace processes. Qualitative agreement of the results indicates reasonability of the calculations and validates the employed sub-models. The described test cases and other experiences with CFD modelling stress the advantages over a purely field data study, such as the ability to quickly and cheaply analyse a variety of design options without actually modifying the object and the availability of significantly more data to interpret the results.

  18. Historic American Engineering Record, Idaho National Laboratory, Idaho Chemical Processing Plant, Fuel Reprocessing Complex

    Energy Technology Data Exchange (ETDEWEB)

    Susan Stacy; Julie Braun

    2006-12-01

    Just as automobiles need fuel to operate, so do nuclear reactors. When fossil fuels such as gasoline are burned to power an automobile, they are consumed immediately and nearly completely in the process. When the fuel is gone, energy production stops. Nuclear reactors are incapable of achieving this near complete burn-up because as the fuel (uranium) that powers them is burned through the process of nuclear fission, a variety of other elements are also created and become intimately associated with the uranium. Because they absorb neutrons, which energize the fission process, these accumulating fission products eventually poison the fuel by stopping the production of energy from it. The fission products may also damage the structural integrity of the fuel elements. Even though the uranium fuel is still present, sometimes in significant quantities, it is unburnable and will not power a reactor unless it is separated from the neutron-absorbing fission products by a method called fuel reprocessing. Construction of the Fuel Reprocessing Complex at the Chem Plant started in 1950 with the Bechtel Corporation serving as construction contractor and American Cyanamid Company as operating contractor. Although the Foster Wheeler Corporation assumed responsibility for the detailed working design of the overall plant, scientists at Oak Ridge designed all of the equipment that would be employed in the uranium separations process. After three years of construction activity and extensive testing, the plant was ready to handle its first load of irradiated fuel.

  19. Complex

    African Journals Online (AJOL)

    CLEMENT O BEWAJI

    Schiff bases and their complex compounds have been studied for their .... establishing coordination of the N–(2 – hydroxybenzyl) - L - α - valine Schiff base ..... (1967); “Spectrophotometric Identification of Organic Compounds”, Willey, New.

  20. Engineering and Coordination of Regulatory Networks and Intracellular Complexes to Maximize Hydrogen Production by Phototrophic Microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    James C. Liao

    2012-05-22

    This project is a collaboration with F. R. Tabita of Ohio State. Our major goal is to understand the factors and regulatory mechanisms that influence hydrogen production. The organisms to be utilized in this study, phototrophic microorganisms, in particular nonsulfur purple (NSP) bacteria, catalyze many significant processes including the assimilation of carbon dioxide into organic carbon, nitrogen fixation, sulfur oxidation, aromatic acid degradation, and hydrogen oxidation/evolution. Our part of the project was to develop a modeling technique to investigate the metabolic network in connection to hydrogen production and regulation. Organisms must balance the pathways that generate and consume reducing power in order to maintain redox homeostasis to achieve growth. Maintaining this homeostasis in the nonsulfur purple photosynthetic bacteria is a complex feat with many avenues that can lead to balance, as these organisms possess versatile metabolic capabilities including anoxygenic photosynthesis, aerobic or anaerobic respiration, and fermentation. Growth is achieved by using H{sub 2} as an electron donor and CO{sub 2} as a carbon source during photoautotrophic and chemoautotrophic growth, where CO{sub 2} is fixed via the Calvin-Benson-Bassham (CBB) cycle. Photoheterotrophic growth can also occur when alternative organic carbon compounds are utilized as both the carbon source and electron donor. Regardless of the growth mode, excess reducing equivalents generated as a result of oxidative processes, must be transferred to terminal electron acceptors, thus insuring that redox homeostasis is maintained in the cell. Possible terminal acceptors include O{sub 2}, CO{sub 2}, organic carbon, or various oxyanions. Cells possess regulatory mechanisms to balance the activity of the pathways which supply energy, such as photosynthesis, and those that consume energy, such as CO{sub 2} assimilation or N{sub 2} fixation. The major route for CO{sub 2} assimilation is the CBB

  1. Stable configurations of graphene on silicon

    Science.gov (United States)

    Javvaji, Brahmanandam; Shenoy, Bhamy Maithry; Mahapatra, D. Roy; Ravikumar, Abhilash; Hegde, G. M.; Rizwan, M. R.

    2017-08-01

    Integration of graphene on silicon-based nanostructures is crucial in advancing graphene based nanoelectronic device technologies. The present paper provides a new insight on the combined effect of graphene structure and silicon (001) substrate on their two-dimensional anisotropic interface. Molecular dynamics simulations involving the sub-nanoscale interface reveal a most favourable set of temperature independent orientations of the monolayer graphene sheet with an angle of ∽15° between its armchair direction and [010] axis of the silicon substrate. While computing the favorable stable orientations, both the translation and the rotational vibrations of graphene are included. The possible interactions between the graphene atoms and the silicon atoms are identified from their coordination. Graphene sheet shows maximum bonding density with bond length 0.195 nm and minimum bond energy when interfaced with silicon substrate at 15° orientation. Local deformation analysis reveals probability distribution with maximum strain levels of 0.134, 0.047 and 0.029 for 900 K, 300 K and 100 K, respectively in silicon surface for 15° oriented graphene whereas the maximum probable strain in graphene is about 0.041 irrespective of temperature. Silicon-silicon dimer formation is changed due to silicon-carbon bonding. These results may help further in band structure engineering of silicon-graphene lattice.

  2. Novel porous scaffolds of pH responsive chitosan/carrageenan-based polyelectrolyte complexes for tissue engineering.

    Science.gov (United States)

    Araujo, J V; Davidenko, N; Danner, M; Cameron, R E; Best, S M

    2014-12-01

    Polyelectrolyte complexes (PECs) represent promising materials for drug delivery and tissue engineering applications. These substances are obtained in aqueous medium without the need for crosslinking agents. PECs can be produced through the combination of oppositely charged medical grade polymers, which include the stimuli responsive ones. In this work, three-dimensional porous scaffolds were produced through the lyophilization of pH sensitive PECs made of chitosan (CS) and carrageenan (CRG). CS:CRG molar ratios of 1:1 (CSCRG1), 2:1 (CSCRG2), and 3:1 (CSCRG3) were used. The chemical compositions of the PECs, as well as their influence in the final structure of the scaffolds were meticulously studied. In addition, the pH responsiveness of the PECs in a range including the physiological pH values of 7.4 (simulating normal physiological conditions) and 4.5 (simulating inflammatory response) was assessed. Results showed that the PECs produced were stable at pH values of 7.4 and under but dissolved as the pH increased to nonphysiological values of 9 and 11. However, after dissolution, the PEC could be reprecipitated by decreasing the pH to values close to 4.5. The scaffolds obtained presented large and interconnected pores, being equally sensitive to changes in the pH. CSCRG1 scaffolds appeared to have higher hydrophilicity and therefore higher water absorption capacity. The increase in the CS:CRG molar ratios improved the scaffold mechanical properties, with CSCRG3 presenting the higher compressive modulus under wet conditions. Overall, the PEC scaffolds appear promising for tissue engineering related applications that require the use of pH responsive materials stable at physiological conditions.

  3. Progress in microwave GaN HEMT grown by MBE on silicon and smart cut TM engineered substrates for high power applications

    OpenAIRE

    2005-01-01

    SiCOI (SiC On Insulator) composite substrates obtained by the Smart-Cut TM process are alternative possible substrates for epitaxial growth of Wide Band Gap (WBG) materials such as GaN and GaN alloys. Similar to bonded SOI structure, the SiCOI structures basically comprises a thin film of single SiC crystal bonded onto a substrate such as, for instance, silicon substrate. Additionally to the well known insulation properties, SiCOI substrates have been proven to be adap...

  4. Progress in microwave GaN HEMT grown by MBE on silicon and smart Cut TM engineered substrates for high power applications

    OpenAIRE

    2005-01-01

    SiCOI (SiC On Insulator) composite substrates obtained by the Smart-Cut TM process are alternative possible substrates for epitaxial growth of Wide Band Gap (WBG) materials such as GaN and GaN alloys. Similar to bonded SOI structure, the SiCOI structures basically comprises a thin film of single SiC crystal bonded onto a substrate such as, for instance, silicon substrate. Additionally to the well known insulation properties, SiCOI substrates have been proven to be adap...

  5. Silicon Brains

    Science.gov (United States)

    Hoefflinger, Bernd

    Beyond the digital neural networks of Chap. 16, the more radical mapping of brain-like structures and processes into VLSI substrates has been pioneered by Carver Mead more than 30 years ago [1]. The basic idea was to exploit the massive parallelism of such circuits and to create low-power and fault-tolerant information-processing systems. Neuromorphic engineering has recently seen a revival with the availability of deep-submicron CMOS technology, which allows for the construction of very-large-scale mixed-signal systems combining local analog processing in neuronal cells with binary signalling via action potentials. Modern implementations are able to reach the complexity-scale of large functional units of the human brain, and they feature the ability to learn by plasticity mechanisms found in neuroscience. Combined with high-performance programmable logic and elaborate software tools, such systems are currently evolving into user-configurable non-von-Neumann computing systems, which can be used to implement and test novel computational paradigms. The chapter introduces basic properties of biological brains with up to 200 Billion neurons and their 1014 synapses, where action on a synapse takes ˜10 ms and involves an energy of ˜10 fJ. We outline 10x programs on neuromorphic electronic systems in Europe and the USA, which are intended to integrate 108 neurons and 1012 synapses, the level of a cat's brain, in a volume of 1 L and with a power dissipation design an intelligent technical response.

  6. Silicon Spintronics

    NARCIS (Netherlands)

    Jansen, R.

    2008-01-01

    Integration of magnetism and mainstream semiconductor electronics could impact information technology in ways beyond imagination. A pivotal step is implementation of spin-based electronic functionality in silicon devices. Remarkable progress made during the last two years gives confidence that this

  7. CARDIAD approach to system dominance with application to turbofan engine models. [Complex Acceptability Region for DIAgonal Dominance in multivariable systems analysis and design

    Science.gov (United States)

    Schafer, R. M.; Sain, M. K.

    1980-01-01

    The paper presents the CARDIAD (complex acceptability region for diagonal dominance) method for achieving the diagonal dominance condition in the inverse Nyquist array approach to the analysis and design of multivariable systems in the frequency domain. A design example is given for a sixth order, 4-input, 4-output model of a turbofan engine.

  8. Understanding the Effects of Team Cognition Associated with Complex Engineering Tasks: Dynamics of Shared Mental Models, Task-SMM, and Team-SMM

    Science.gov (United States)

    Lee, Miyoung; Johnson, Tristan E.

    2008-01-01

    This study investigates how shared mental models (SMMs) change over time in teams of students in a manufacturing engineering course. A complex ill-structured project was given to each team. The objective of the team project was to analyze, test, and propose ways to improve their given manufactured product. Shared mental models were measured in…

  9. Silicon nitride for lightweight stiff structures for optical instruments

    Science.gov (United States)

    Berroth, Karl; Devilliers, Christophe; Luichtel, Georg

    2009-08-01

    Due to their very specific set of material properties, silicon nitride and silicon carbide have gained a lot of interest in the last 20 years. Moreover, many new approaches in technical equipment and processes were enabled with corresponding research and production activities. Also large efforts were made at FCT during the last years, to get able to supply even very large and complex shaped components made of sintered silicon carbide (SSiC) and of gas pressure sintered silicon nitride (GPSN) ceramics. This approach has opened new applications and markets for such ceramic materials. On the other side, designers and engineers are now allowed to think much more complex in designing of ceramic components. In this paper, a new rapid prototyping routine for very complex components as well as the corresponding materials will be presented. Components for optical equipment in innovative avionic and space applications, and more conventional technologies are described. Not only their unique key intrinsic properties, like high Youngs Modulus, very low CTE, very high strength and fracture toughness for a ceramic but also newly developed and adopted shaping, sintering and machining technologies in both green and sintered state have let to highly valued products. This enabled FCT to offer Carl Zeiss Optronics using silicon nitride for a newly designed, very complex housing structure of an avionic pod camera. Due to a very low CTE, high stiffness and less weight, an improved performance was reached. Also Thales Alenia Space is engaged since some years in activities to develop and qualify Silicon nitride ceramics for space projects. Extremely stiff, very lightweight and large truss space structures with a very low CTE, high rigidity and no outgasing for satellites can now be realized. Deep tests sequence has been performed to qualify truss beams and end fittings made in the same material. Also advanced dynamic testing equipment for avionic turbine blades requires new approaches. In

  10. Game-theory-based search engine to automate the mass assignment in complex native electrospray mass spectra.

    Science.gov (United States)

    Tseng, Yao-Hsin; Uetrecht, Charlotte; Yang, Shih-Chieh; Barendregt, Arjan; Heck, Albert J R; Peng, Wen-Ping

    2013-12-03

    Electrospray ionization coupled to native mass spectrometry (MS) has evolved into an important tool in structural biology to decipher the composition of protein complexes. However, the mass analysis of heterogeneous protein assemblies is hampered because of their overlapping charge state distributions, fine structure, and peak broadening. To facilitate the mass analysis, it is of importance to automate preprocessing raw mass spectra, assigning ion series to peaks and deciphering the subunit compositions. So far, the automation of preprocessing raw mass spectra has not been accomplished; Massign was introduced to simplify data analysis and decipher the subunit compositions. In this study, we develop a search engine, AutoMass, to automatically assign ion series to peaks without any additional user input, for example, limited ranges of charge states or ion mass. AutoMass includes an ion intensity-dependent method to check for Gaussian distributions of ion series and an ion intensity-independent method to address highly overlapping and non-Gaussian distributions. The minimax theorem from game theory is adopted to define the boundaries. With AutoMass, the boundaries of ion series in the well-resolved tandem mass spectra of the hepatitis B virus (HBV) capsids and those of the mass spectrum from CRISPR-related cascade protein complex are accurately assigned. Theoretical and experimental HBV ion masses are shown in agreement up to ~0.03%. The analysis is finished within a minute on a regular workstation. Moreover, less well-resolved mass spectra, for example, complicated multimer mass spectra and norovirus capsid mass spectra at different levels of desolvation, are analyzed. In sum, this first-ever fully automatic program reveals the boundaries of overlapping ion peak series and can further aid developing high-throughput native MS and top-down proteomics.

  11. Lithographically patterned silicon nanostructures on silicon substrates

    Energy Technology Data Exchange (ETDEWEB)

    Megouda, Nacera [Institut de Recherche Interdisciplinaire (IRI, USR 3078), Universite Lille1, Parc de la Haute Borne, 50 Avenue de Halley-BP 70478, 59658 Villeneuve d' Ascq and Institut d' Electronique, de Microelectronique et de Nanotechnologie (IEMN, CNRS-8520), Cite Scientifique, Avenue Poincare-B.P. 60069, 59652 Villeneuve d' Ascq (France); Faculte des Sciences, Universite Mouloud Mammeri, Tizi-Ouzou (Algeria); Unite de Developpement de la Technologie du Silicium (UDTS), 2 Bd. Frantz Fanon, B.P. 140 Alger-7 merveilles, Alger (Algeria); Piret, Gaeelle; Galopin, Elisabeth; Coffinier, Yannick [Institut de Recherche Interdisciplinaire (IRI, USR 3078), Universite Lille1, Parc de la Haute Borne, 50 Avenue de Halley-BP 70478, 59658 Villeneuve d' Ascq and Institut d' Electronique, de Microelectronique et de Nanotechnologie (IEMN, CNRS-8520), Cite Scientifique, Avenue Poincare-B.P. 60069, 59652 Villeneuve d' Ascq (France); Hadjersi, Toufik, E-mail: hadjersi@yahoo.com [Unite de Developpement de la Technologie du Silicium (UDTS), 2 Bd. Frantz Fanon, B.P. 140 Alger-7 merveilles, Alger (Algeria); Elkechai, Omar [Faculte des Sciences, Universite Mouloud Mammeri, Tizi-Ouzou (Algeria); and others

    2012-06-01

    The paper reports on controlled formation of silicon nanostructures patterns by the combination of optical lithography and metal-assisted chemical dissolution of crystalline silicon. First, a 20 nm-thick gold film was deposited onto hydrogen-terminated silicon substrate by thermal evaporation. Gold patterns (50 {mu}m Multiplication-Sign 50 {mu}m spaced by 20 {mu}m) were transferred onto the silicon wafer by means of photolithography. The etching process of crystalline silicon in HF/AgNO{sub 3} aqueous solution was studied as a function of the silicon resistivity, etching time and temperature. Controlled formation of silicon nanowire arrays in the unprotected areas was demonstrated for highly resistive silicon substrate, while silicon etching was observed on both gold protected and unprotected areas for moderately doped silicon. The resulting layers were characterized using scanning electron microscopy (SEM).

  12. Silylene hydride complexes of molybdenum with silicon-hydrogen interactions: neutron structure of (eta(5)-C(5)Me(5))(Me(2)PCH(2)CH(2)PMe(2))Mo(H)(SiEt(2)).

    Science.gov (United States)

    Mork, Benjamin V; Tilley, T Don; Schultz, Arthur J; Cowan, John A

    2004-08-25

    Reduction of CpMoCl(4) with 3.1 equiv of Na/Hg amalgam (1.0% w/w) in the presence of 1 equiv of dmpe and 1 equiv of trimethylphosphine afforded the molybdenum(II) chloride complex Cp(dmpe)(PMe(3))MoCl (1) (Cp = 1,2,3,4,5-pentamethylcyclopentadienyl, dmpe = 1,2-bis(dimethylphosphino)ethane). Alkylation of 1 with PhCH(2)MgCl proceeded in high yield to liberate PMe(3) and give the 18-electron pi-benzyl complex Cp(dmpe)Mo(eta(3)-CH(2)Ph) (2). Variable temperature NMR experiments provided evidence that 2 is in equilibrium with its 16-electron eta(1)-benzyl isomer [Cp(dmpe)Mo(eta(1)-CH(2)Ph)]. This was further supported by reaction of 2 with CO to yield the carbonyl benzyl complex Cp(dmpe)(CO)Mo(eta(1)-CH(2)Ph) (3). Complex 2 was found to react with disubstituted silanes H(2)SiRR' (RR' = Me(2), Et(2), MePh, and Ph(2)) to form toluene and the silylene complexes Cp(dmpe)Mo(H)(SiRR') (4a: RR' = Me(2); 4b: RR' = Et(2); 4c: RR' = MePh; 4d: RR' = Ph(2)). Reactions of 2 with monosubstituted silanes H(3)SiR (R = Ph, Mes, Mes = 2,4,6-trimethylphenyl) produced rare examples of hydrosilylene complexes Cp(dmpe)Mo(H)Si(H)R (5a: R = Ph; 5b: R = Mes; 5c: R = CH(2)Ph). Reactivity of complexes 4a-c and 5a-d is dominated by 1,2-hydride migration from metal to silicon, and these complexes possess H.Si bonding interactions, as supported by spectroscopic and structural data. For example, the J(HSi) coupling constants in these species range in value from 30 to 48 Hz and are larger than would be expected in the absence of H.Si bonding. A neutron diffraction study on a single crystal of diethylsilylene complex 4b unequivocally determined the hydride ligand to be in a bridging position across the molybdenum-silicon bond (Mo-H 1.85(1) A, Si-H 1.68(1) A). The synthesis and reactivity properties of these complexes are described in detail.

  13. Why Model-Based Engineering and Manufacturing Makes Sense for the Plants and Laboratories of the Nuclear Weapon Complex

    Energy Technology Data Exchange (ETDEWEB)

    Franklin, K W; Howell, L N; Lewis, D G; Neugebauer, C A; O' Brien, D W; Schilling, S A

    2001-05-15

    The purpose of this White Paper is to outline the benefits we expect to receive from Model-Based Engineering and Manufacturing (MBE/M) for the design, analysis, fabrication, and assembly of nuclear weapons for upcoming Life Extension Programs (LEPs). Industry experiences with model-based approaches and the NNSA/DP investments and experiences, discussed in this paper, indicate that model-based methods can achieve reliable refurbished weapons for the stockpile with less cost and time. In this the paper, we list both general and specific benefits of MBE/M for the upcoming LEPs and the metrics for determining the success of model-based approaches. We also present some outstanding issues and challenges to deploying and achieving long-term benefit from the MBE/M. In conclusion, we argue that successful completion of the upcoming LEPs--with very aggressive schedule and funding restrictions--will depend on electronic model-based methods. We ask for a strong commitment from LEP managers throughout the Nuclear Weapons Complex to support deployment and use of MBE/M systems to meet their program needs.

  14. Metabolic engineering of Arabidopsis for remediation of different polycyclic aromatic hydrocarbons using a hybrid bacterial dioxygenase complex.

    Science.gov (United States)

    Peng, Rihe; Fu, Xiaoyan; Tian, Yongsheng; Zhao, Wei; Zhu, Bo; Xu, Jing; Wang, Bo; Wang, Lijuan; Yao, Quanhong

    2014-11-01

    The widespread presence of polycyclic aromatic hydrocarbons (PAHs) and their potential harm to various organisms has generated interest in efficiently eliminating these compounds from the environment. Phytoremediation is an efficient technology for cleaning up pollutants. However, unlike microorganisms, plants lack the catabolic pathway for complete degradation of these dangerous groups of compounds. One way to enhance the potential of plants for remediation of these compounds is by transferring genes involved in xenobiotic degradation from microbes to plants. In this paper, four genes, namely nidA and nidB (encoding the large and small subunits of naphthalene dioxygenase of Mycobacterium vanbaalenii PYR-1) as well as NahAa and NahAb (encoding flavoprotein reductase and ferredoxin of the electron-transport chain of the Pseudomonas putida G7 naphthalene dioxygenase system), were transferred and ectopically expressed in Arabidopsis thaliana. Transgenic Arabidopsis plants overexpressing the heterozygous naphthalene dioxygenase system exhibited enhanced tolerance toward 2-4 rings PAHs. Transgenic plants assimilated PAHs from the culture media faster and accumulated less in vivo than wild-type plants. Furthermore, examination of metabolic intermediates by gas chromatography-mass spectrometry revealed that the naphthalene metabolic pathway in transgenic plants mainly involves the dioxygenase pathway. Taken together, our findings suggest that grafting the naphthalene dioxygenase complex into plants is a possible strategy to breed PAH-tolerant plants to efficiently degrade PAHs in the environment. Copyright © 2014 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  15. Monocrystalline silicon used for integrated circuits: still on the way

    Institute of Scientific and Technical Information of China (English)

    Jia-he CHEN; De-ren YANG; Duan-lin QUE

    2008-01-01

    With the rapid development of semiconductor technology, highly integrated circuits (ICs) and future nano-scale devices require large diameter and defect-free monocrystalline silicon wafers. The ongoing innovation from silicon materials is one of the driving forces in future micro and nano-technologies. In this work, the recent developments in the controlling of large diameter silicon crystal growth processes, the improvement of material features by co-doping with the intend-introduced impur-ities, and the progress of defect engineered silicon wafers (epitaxial silicon wafer, strained silicon, silicon on insu-lator) are reviewed. It is proposed that the silicon man-ufacturing infrastructure could still meet the increasingly stringent requirements arising from ULSI circuits and will expand Moore's law into a couple of decades.

  16. New Perspective of High-Pure Silicon

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@The discovery in the middle of 1950s of the semi-con ducting properties of crystalline silicon has led to the impetu ous development of electric power facilities, the sun-power industry, and particularly, the microelectronic industry. The increasing demand for the high-pure silicon requires the production of synthetic crystals. The raw material for the syn thetic crystals, the so-called technical, or metallurgical silicon, is obtained from quartzite and quartz of superior quality by means of carbon-thermal reduction of silicon using an electric arc discharge. The complexity of the technological process, high cost of the related facilities, worsening environmental pollution, and narrow-mindedness of a raw material company are attributed to the rise in price of the final product-silicon plates, resulting in the fall in the production of high-pure silicon, normally used in sun storage batteries.

  17. Genetically engineered excitable cardiac myofibroblasts coupled to cardiomyocytes rescue normal propagation and reduce arrhythmia complexity in heterocellular monolayers.

    Directory of Open Access Journals (Sweden)

    Luqia Hou

    Full Text Available RATIONALE AND OBJECTIVE: The use of genetic engineering of unexcitable cells to enable expression of gap junctions and inward rectifier potassium channels has suggested that cell therapies aimed at establishing electrical coupling of unexcitable donor cells to host cardiomyocytes may be arrhythmogenic. Whether similar considerations apply when the donor cells are electrically excitable has not been investigated. Here we tested the hypothesis that adenoviral transfer of genes coding Kir2.1 (I(K1, Na(V1.5 (I(Na and connexin-43 (Cx43 proteins into neonatal rat ventricular myofibroblasts (NRVF will convert them into fully excitable cells, rescue rapid conduction velocity (CV and reduce the incidence of complex reentry arrhythmias in an in vitro model. METHODS AND RESULTS: We used adenoviral (Ad- constructs encoding Kir2.1, Na(V1.5 and Cx43 in NRVF. In single NRVF, Ad-Kir2.1 or Ad-Na(V1.5 infection enabled us to regulate the densities of I(K1 and I(Na, respectively. At varying MOI ratios of 10/10, 5/10 and 5/20, NRVF co-infected with Ad-Kir2.1+ Na(V1.5 were hyperpolarized and generated action potentials (APs with upstroke velocities >100 V/s. However, when forming monolayers only the addition of Ad-Cx43 made the excitable NRVF capable of conducting electrical impulses (CV = 20.71±0.79 cm/s. When genetically engineered excitable NRVF overexpressing Kir2.1, Na(V1.5 and Cx43 were used to replace normal NRVF in heterocellular monolayers that included neonatal rat ventricular myocytes (NRVM, CV was significantly increased (27.59±0.76 cm/s vs. 21.18±0.65 cm/s, p<0.05, reaching values similar to those of pure myocytes monolayers (27.27±0.72 cm/s. Moreover, during reentry, propagation was faster and more organized, with a significantly lower number of wavebreaks in heterocellular monolayers formed by excitable compared with unexcitable NRVF. CONCLUSION: Viral transfer of genes coding Kir2.1, Na(V1.5 and Cx43 to cardiac myofibroblasts endows them with

  18. Ultrafast laser functionalized rare phased gold-silicon/silicon oxide nanostructured hybrid biomaterials.

    Science.gov (United States)

    Premnath, P; Tan, B; Venkatakrishnan, K

    2015-12-01

    We introduce a hybrid nanostructured biomaterial that is a combination of rare phases of immiscible gold and silicon oxide, functionalized via ultrafast laser synthesis. For the first time, we show cancer controlling properties of rare phases of gold silicides, which include Au7Si, Au5Si, Au0.7Si2.3 and Au8Si2. Conventionally, pure forms of gold and silicon/silicon oxide are extensively employed in targeted therapy and drug delivery systems due to their unique properties. While silicon and silicon oxide nanoparticles have shown biocompatibility, gold nanoparticles show conflicting results based on their size and material properties. Several studies have shown that gold and silicon combinations produce cell controlling properties, however, these studies were not able to produce a homogenous combination of gold and silicon, owing to its immiscibility. A homogenous combination of gold and silicon may potentially enable properties that have not previously been reported. We describe rare phased gold-silicon oxide nanostructured hybrid biomaterials and its unique cancer controlling properties, owing to material properties, concentration, size and density. The gold-silicon oxide nanostructured hybrid is composed of individual gold-silicon oxide nanoparticles in various concentrations of gold and silicon, some nanoparticles possess a gold-core and silicon-shell like structure. The individual nanoparticles are bonded together forming a three dimensional nanostructured hybrid. The interaction of the nanostructured hybrids with cervical cancer cells showed a 96% reduction in 24h. This engineered nanostructured hybrid biomaterial presents significant potential due to the combination of immiscible gold and silicon oxide in varying phases and can potentially satiate the current vacuum in cancer therapy.

  19. Phonon processes in vertically aligned silicon nanowire arrays produced by low-cost all-solution galvanic displacement method

    Science.gov (United States)

    Banerjee, Debika; Trudeau, Charles; Gerlein, Luis Felipe; Cloutier, Sylvain G.

    2016-03-01

    The nanoscale engineering of silicon can significantly change its bulk optoelectronic properties to make it more favorable for device integration. Phonon process engineering is one way to enhance inter-band transitions in silicon's indirect band structure alignment. This paper demonstrates phonon localization at the tip of silicon nanowires fabricated by galvanic displacement using wet electroless chemical etching of a bulk silicon wafer. High-resolution Raman micro-spectroscopy reveals that such arrayed structures of silicon nanowires display phonon localization behaviors, which could help their integration into the future generations of nano-engineered silicon nanowire-based devices such as photodetectors and solar cells.

  20. Dissolution of bulk specimens of silicon nitride

    Science.gov (United States)

    Davis, W. F.; Merkle, E. J.

    1981-01-01

    An accurate chemical characterization of silicon nitride has become important in connection with current efforts to incorporate components of this material into advanced heat engines. However, there are problems concerning a chemical analysis of bulk silicon nitride. Current analytical methods require the pulverization of bulk specimens. A pulverization procedure making use of grinding media, on the other hand, will introduce contaminants. A description is given of a dissolution procedure which overcomes these difficulties. It has been found that up to at least 0.6 g solid pieces of various samples of hot pressed and reaction bonded silicon nitride can be decomposed in a mixture of 3 mL hydrofluoric acid and 1 mL nitric acid overnight at 150 C in a Parr bomb. High-purity silicon nitride is completely soluble in nitric acid after treatment in the bomb. Following decomposition, silicon and hydrofluoric acid are volatilized and insoluble fluorides are converted to a soluble form.

  1. Reticulated porous silicon nitride-based ceramics

    OpenAIRE

    Mazzocchi, Mauro; Medri, Valentina; Guicciardi, Stefano

    2012-01-01

    The interest towards the production of porous silicon nitride originates from the unique combination of light weight, of mechanical and physical properties typical of this class of ceramics that make them attractive for many engineering applications. Although pores are generally believed to deteriorate the mechanical properties of ceramics (the strength of porous ceramics decreases exponentially with an increase of porosity), the recent literature reports that porous silicon nitride can exhib...

  2. The Bacterial Flagellar Type III Export Gate Complex Is a Dual Fuel Engine That Can Use Both H+ and Na+ for Flagellar Protein Export.

    Science.gov (United States)

    Minamino, Tohru; Morimoto, Yusuke V; Hara, Noritaka; Aldridge, Phillip D; Namba, Keiichi

    2016-03-01

    The bacterial flagellar type III export apparatus utilizes ATP and proton motive force (PMF) to transport flagellar proteins to the distal end of the growing flagellar structure for self-assembly. The transmembrane export gate complex is a H+-protein antiporter, of which activity is greatly augmented by an associated cytoplasmic ATPase complex. Here, we report that the export gate complex can use sodium motive force (SMF) in addition to PMF across the cytoplasmic membrane to drive protein export. Protein export was considerably reduced in the absence of the ATPase complex and a pH gradient across the membrane, but Na+ increased it dramatically. Phenamil, a blocker of Na+ translocation, inhibited protein export. Overexpression of FlhA increased the intracellular Na+ concentration in the presence of 100 mM NaCl but not in its absence, suggesting that FlhA acts as a Na+ channel. In wild-type cells, however, neither Na+ nor phenamil affected protein export, indicating that the Na+ channel activity of FlhA is suppressed by the ATPase complex. We propose that the export gate by itself is a dual fuel engine that uses both PMF and SMF for protein export and that the ATPase complex switches this dual fuel engine into a PMF-driven export machinery to become much more robust against environmental changes in external pH and Na+ concentration.

  3. The Bacterial Flagellar Type III Export Gate Complex Is a Dual Fuel Engine That Can Use Both H+ and Na+ for Flagellar Protein Export.

    Directory of Open Access Journals (Sweden)

    Tohru Minamino

    2016-03-01

    Full Text Available The bacterial flagellar type III export apparatus utilizes ATP and proton motive force (PMF to transport flagellar proteins to the distal end of the growing flagellar structure for self-assembly. The transmembrane export gate complex is a H+-protein antiporter, of which activity is greatly augmented by an associated cytoplasmic ATPase complex. Here, we report that the export gate complex can use sodium motive force (SMF in addition to PMF across the cytoplasmic membrane to drive protein export. Protein export was considerably reduced in the absence of the ATPase complex and a pH gradient across the membrane, but Na+ increased it dramatically. Phenamil, a blocker of Na+ translocation, inhibited protein export. Overexpression of FlhA increased the intracellular Na+ concentration in the presence of 100 mM NaCl but not in its absence, suggesting that FlhA acts as a Na+ channel. In wild-type cells, however, neither Na+ nor phenamil affected protein export, indicating that the Na+ channel activity of FlhA is suppressed by the ATPase complex. We propose that the export gate by itself is a dual fuel engine that uses both PMF and SMF for protein export and that the ATPase complex switches this dual fuel engine into a PMF-driven export machinery to become much more robust against environmental changes in external pH and Na+ concentration.

  4. RCRA Part B Permit Application for the Idaho National Engineering Laboratory - Volume 5 Radioactive Waste Management Complex

    Energy Technology Data Exchange (ETDEWEB)

    Pamela R. Cunningham

    1992-07-01

    This section of the Radioactive Waste Management Complex (RWMC) Part B permit application describes the waste characteristics Of the transuranic (TRU) mixed wastes at the RWMC waste management units to be permitted: the Intermediate-Level Transuranic Storage Facility (ILTSF) and the Waste Storage Facility (WSF). The ILTSF is used to store radioactive remote-handled (RH) wastes. The WSF will be used to store radioactive contact-handled (CH) wastes. The Transuranic Storage Area (TSA) was established at the RWMC to provide interim storage of TRU waste. Department of Energy (DOE) Order 5820.2A defines TRU waste as waste contaminated with alpha-emitting transuranium radionuclides with half-lives greater than 20 years in concentrations greater than 100 nanocuries per gram (nCi/g) o f waste material. The TSA serves generators both on and off the Idaho National Engineering Laboratory (INEL). The ILTSF is located at the TSA, and the WSF will be located there also. Most of the wastes managed at the TSA are mixed wastes, which are radioactive wastes regulated under the Atomic Energy Act (AEA) that also contain hazardous materials regulated under the Resource Conservation and Recovery Act (RCRA) and the Idaho Hazardous Waste Management Regulations. These wastes include TRU mixed wastes and some low-level mixed wastes. Accordingly, the TSA is subject to the permitting requirements of RCRA and the Idaho Administrative Procedures Act (IDAPA). Prior to 1982, DOE orders defined TRU wastes as having transuranium radionuclides in concentrations greater than 10 nCi/g, The low-level mixed wastes managed at the TSA are those wastes with 10 to 100 nCi/g of TRU radionuclides that prior to 1982 were considered TRU waste.

  5. DEFINING ‘PROJECT SUCCESS’ FOR A COMPLEX PROJECT – THE CASE OF A NUCLEAR ENGINEERING DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    S.I. Van Niekerk

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: The case of a nuclear engineering project was investigated to establish the relevant success criteria for the development of complex, high-technology systems. The project was first categorised according to an existing scheme, and the Delphi method was used to determine the criteria for project success that apply to this specific case. A framework of project success dimensions was extended to include criteria that are of specific importance for the project under consideration.

    While project efficiency (delivery on time and within budget obviously still needs to be controlled, the results provide empirical evidence for the notion that, for ‘super high tech’ projects, this is relatively less important. The relative importance of the dimensions of success was also evaluated and presented on a timeline stretching from project execution to 10 years after project completion. This provided empirical evidence for certain concepts in the literature.

    AFRIKAANSE OPSOMMING: Die geval van ʼn kern-ingenieursprojek is ondersoek om die relevante kriteria vir sukses vir die ontwikkeling van komplekse hoë-tegnologiesisteme te bepaal. Die projek is eerstens geklassifiseer volgens ʼn bestaande skema, en die Delphi-metode is vervolgens gebruik om die relevante kriteria vir projeksukses vir die betrokke geval te bepaal. ʼn Bestaande raamwerk van dimensies vir projeksukses is uitgebrei om kriteria wat van spesifieke belang vir die betrokke geval in te sluit.

    Terwyl tydige aflewering, binne begroting natuurlik steeds belangrik is, voorsien die resultate empiriese bewys vir die nosie in die literatuur dat hierdie aspekte van relatief minder belang is in die geval van ‘super hoë-tegnologie’-projekte. Die relatiewe belangrikheid van die dimensies van sukses is ook evalueer, en aangedui op ʼn tydlyn wat strek van projekuitvoering tot 10 jaar na die afhandeling van die projek. Dit lewer empiriese bewys vir sekere bewerings in

  6. X-traktor: A Rookie Robot, Simple, Yet Complex, Impeccably Designed, a Very Innovative Multidisciplinary Engineering Masterpiece

    Science.gov (United States)

    Henderson, A. J., Jr.

    2001-01-01

    FIRST is the acronym of For Inspiration and Recognition of Science and Technology. FIRST is a 501.C.3 non-profit organization whose mission is to generate an interest in science and engineering among today's young adults and youth. This mission is accomplished through a robot competition held annually in the spring of each year. NASAs Marshall Space Flight Center, Education Programs Department, awarded a grant to Lee High School, the sole engineering magnet school in Huntsville, Alabama. MSFC awarded the grant in hopes of fulfilling its goal of giving back invaluable resources to its community and engineers, as well as educating tomorrow's work force in the high-tech area of science and technology. Marshall engineers, Lee High School students and teachers, and a host of other volunteers and parents officially initiated this robot design process and competitive strategic game plan. The FIRST Robotics Competition is a national engineering contest, which immerses high school students in the exciting world of science and engineering. Teaming with engineers from government agencies, businesses, and universities enables the students to learn about the engineering profession. The students and engineers have six weeks to work together to brainstorm, design, procure, construct, and test their robot. The team then competes in a spirited, 'no-holds barred' tournament, complete with referees, other FIRST-designed robots, cheerleaders, and time clocks. The partnerships developed between schools, government agencies, businesses, and universities provide an exchange of resources and talent that build cooperation and expose students to new and rewarding career options. The result is a fun, exciting, and stimulating environment in which all participants discover the important connections between classroom experiences and real-world applications. This paper will highlight the story, engineering development, and evolutionary design of Xtraktor, the rookie robot, a manufacturing

  7. Thermodynamics of Volatile Silicon Hydroxides Studied

    Science.gov (United States)

    Copland, Evan H.; Opila, Elizabeth J.; Jacobson, Nathan S.

    2001-01-01

    Silicon-based ceramics are promising candidate structural materials for heat engines. The long-term stability of these materials to environmental degradation is dependent on the formation and retention of a protective SiO2 layer. It is well known that SiO2 forms stable volatile hydroxides in the presence of water vapor at elevated temperatures. Combustion conditions, which characteristically are at high velocities, contain significant water vapor pressures, and high temperatures tend to promote continuous formation of these hydroxides with resulting material degradation. For the degradation of silicon-based ceramics to be predicted, accurate thermodynamic data on the formation of silicon hydroxides are needed.

  8. A general classification of silicon utilizing organisms

    Science.gov (United States)

    Das, P.; Das, S.

    2010-12-01

    Silicon utilizing organisms may be defined as organisms with high silicon content (≥ 1% dry weight) and they can metabolize silicon with or without demonstrable silicon transporter genes (SIT) in them(Das,2010). Silicon is the second most abundant element in the lithosphere (27.70%) and it is as important as phosphorus and magnesium (0.03%) in the biota. Hydrated silica represents the second most abundant biogenic mineral after carbonate minerals. Silicon is accumulated and metabolized by some prokaryotes, and Si compounds can stimulate the growth of a range of fungi. It is well known that Si is essential for diatoms. In mammals, Si is considered an essential trace element, required in bone, cartilage and connective tissue formation, enzymatic activities and other metabolic processes. Silicon was suggested to act as a phosphoprotein effector in bone. In mammals, Si is also reported to positively influence the immune system and to be required for lymphocyte proliferation. The aqueous chemistry of Si is dominated by silicic acid at biological pH ranges. Monosilicic acid can form stable complexes with organic hydroxy-containing molecules . Biosilica also has been identified associated with various biomolecules including proteins and carbohydrates. There are main seven groups of silicon utilizing organisms belonging to Gram positive bacteria, algae, protozoa, sponges, fungi, lichens, and monocotyledon plants. In each group again all the members are not silicon utilizing organisms, thus selective members in each group are further classified depending their degree of silicon utilization. Important silicon utilizing bacteria are Mycobacteria, Nocardia, Streptomyces, Staphylococcus, Bacillus, Lactobacillus spp. etc., Important silicon utilizing algae are Centrobacillariophyceae, Pennatibacillariophyceae and Chrysophyceae. Many protozoa belonging to Heterokonta, Choanoflagellida, Actinopoda are well known silicon utilizing microorganisms. Hexactinellida ( glass sponges

  9. Electrical engineer's reference book

    CERN Document Server

    Laughton, M A

    1985-01-01

    Electrical Engineer's Reference Book, Fourteenth Edition focuses on electrical engineering. The book first discusses units, mathematics, and physical quantities, including the international unit system, physical properties, and electricity. The text also looks at network and control systems analysis. The book examines materials used in electrical engineering. Topics include conducting materials, superconductors, silicon, insulating materials, electrical steels, and soft irons and relay steels. The text underscores electrical metrology and instrumentation, steam-generating plants, turbines

  10. Application of high-density silicone oil in complex retinal detachment surgery%重硅油在复杂性视网膜脱离手术中的应用

    Institute of Scientific and Technical Information of China (English)

    曲申; 荣翱

    2012-01-01

    微创玻璃体手术的快速发展,为视网膜脱离的患者带来福音.许多以前无法治疗的复杂性视网膜脱离得到解剖复位,术后视力得以提高.良好的玻璃体替代物对玻璃体手术的疗效及技术的改进具有非常重要的意义.目前临床上常用的硅油和长效气体( C3F8)比重都比水小,对下方视网膜脱离顶压不足,而且术后患者要保持俯卧体位.重硅油比重比水大,可以对下方视网膜产生有效顶压.本文就重硅油的理化性质、临床应用、治疗效果及并发症等作一简要综述.%The rapid development of micro-invasive vitrectomy bring the good news for the majority of patients suffering from retinal detachment.Many previously untreatable complex retinal,detachment could be anatomic reattached,postoperative visual acuity could be improved.Vitreous substitute for good efficacy of vitreous surgery and improvements in technology has a very important significance.Currently used materials,such as silicone oil and C3 F8 were lighter in proportion than water,and postoperative prone position was necessary to maintain.The high-density silicone oil,can make an effective top pressure on the retina.In this review,the physical and chemical properties of high-density silicone oil,clinical application,treatment and complications were overviewed.

  11. Providing Formative Assessment to Students Solving Multipath Engineering Problems with Complex Arrangements of Interacting Parts: An Intelligent Tutor Approach

    Science.gov (United States)

    Steif, Paul S.; Fu, Luoting; Kara, Levent Burak

    2016-01-01

    Problems faced by engineering students involve multiple pathways to solution. Students rarely receive effective formative feedback on handwritten homework. This paper examines the potential for computer-based formative assessment of student solutions to multipath engineering problems. In particular, an intelligent tutor approach is adopted and…

  12. Surface Engineering of Polycrystalline Silicon for Long-term Mechanical Stress Endurance Enhancement in Flexible Low Temperature Poly-Si Thin-Film Transistors.

    Science.gov (United States)

    Chen, Bo-Wei; Chang, Ting-Chang; Hung, Yu-Ju; Huang, Shin-Ping; Chen, Hua-Mao; Liao, Po-Yung; Lin, Yu-Ho; Huang, Hui-Chun; Chiang, Hsiao-Cheng; Yang, Chung-I; Zheng, Yu-Zhe; Chu, Ann-Kuo; Li, Hung-Wei; Tsai, Chih-Hung; Lu, Hsueh-Hsing; Wang, Terry Tai-Jui; Chang, Tsu-Chiang

    2017-02-08

    Surface morphology in polycrystalline silicon (poly-Si) film is an issue regardless of whether conventional excimer laser annealing (ELA) or the newer metal-induced lateral crystallization (MILC) process is used. This paper investigates the stress distribution while undergoing long-term mechanical stress and the influence of stress on electrical characteristics. Our simulated results show that the non-uniform stress in the gate insulator is more pronounced near the polysilicon/gate insulator edge and at the two sides of the polysilicon protrusion. This stress results in defects in the gate insulator and leads to a non-uniform degradation phenomenon, which affects both the performance and reliability in thin-film transistors (TFTs). The degree of degradation is similar regardless of bending axis (channel-length axis, channel-width axis) or bending type (compression, tension), which means that the degradation is dominated by the protrusion effects. Furthermore, by utilizing long-term electrical bias stresses after undergoing long-tern bending stress, it is apparent that the carrier injection is severe in the sub-channel region, which confirms that the influence of protrusions is crucial. To eliminate the influence of surface morphology in poly-Si, three kinds of laser energy density were used during crystallization to control the protrusion height. The device with lowest protrusions demonstrates the smallest degradation after undergoing long-term bending.

  13. Zhongguan Village, China's Silicon Valley

    Institute of Scientific and Technical Information of China (English)

    Liu Xinwen

    2008-01-01

    @@ In 1999,driven by the dream of using technology to change people's lives,Li Yanhong,returned to Zhongguancun(Zhongguan Village in Chinese),Beijing from Silicon Valley in the U.S.to create Baidu.com.Over the years,Baidu has become the most frequently hitted website in China as well as the largest Chinesc search engine and Chinese language website in the world.

  14. COMPLEX QUERY AND METADATA

    OpenAIRE

    Nakatoh, Tetsuya; Omori, Keisuke; Yamada, Yasuhiro; Hirokawa, Sachio

    2003-01-01

    We are developing a search system DAISEn which integrates multiple search engines and generates a metasearch engine automatically. The target search engines of DAISEn are not general search engines, but are search engines specialized in some area. Integration of such engines yields efficiency and quality. There are search engines of new type which accept complex query and return structured data. Integration of such search engines is much harder than that of simple search engines which accept ...

  15. Process Description and Operating History for the CPP-601/-640/-627 Fuel Reprocessing Complex at the Idaho National Engineering and Environmental Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    E. P. Wagner

    1999-06-01

    The Fuel Reprocessing Complex (FRC) at the Idaho Nuclear Technology and Engineering Center at the Idaho National Engineering and Environmental Laboratory was used for reprocessing spent nuclear fuel from the early 1950's until 1992. The reprocessing facilities are now scheduled to be deactivated. As part of the deactivation process, three Resource Conservation and Recovery Act (RCRA) interim status units located in the complex must be closed. This document gathers the historical information necessary to provide a rational basis for the preparation of a comprehensive closure plan. Included are descriptions of process operations and the operating history of the FRC. A set of detailed tables record the service history and present status of the process vessels and transfer lines.

  16. Damage characterisation of silicon carbides for applications in gas turbines in complex load conditions; Charakterisierung des Schaedigungsverhaltens von Siliciumcarbiden fuer den Einsatz in Gasturbinen unter komplexen Beanspruchungsbedingungen

    Energy Technology Data Exchange (ETDEWEB)

    Nestle, E.

    2000-06-01

    A tensile test facility for simultaneous thermal, mechanical and corrosive loading was developed and constructed for the purpose of characterizing the damage characteristics of ceramic high-temperature materials. Apart from tensile tests for up to 830 h, tests were also carried out on four-point bending test pieces and disk-shaped oxidation test pieces. The experiments were made at 1450 - 1550 C in dry or moist air. The materials investigated were one hot-pressed silicon carbide and two sintered silicon carbides. [German] Um keramische Hochtemperaturwerkstoffe bezueglich ihres Schaedigungsverhaltens charakterisieren zu koennen, wurde im Rahmen der vorliegenden Arbeit eine Zugpruefanlage zur gleichzeitigen Beanspruchung unter thermischen, mechanischen und korrosiven Bedingungen entwickelt und aufgebaut. Neben den in dieser Anlage durchgefuehrten Zugpruefungen mit Versuchszeiten bis zu 830 h wurden begleitende Untersuchungen an Vierpunkt-Biegeproben und scheibenfoermigen Oxidationsproben durchgefuehrt. Die Versuche konzentrierten sich auf den Temperaturbereich 1450-1550 unter trockenen und feuchten Luftatmosphaeren. Bei den untersuchten Werkstoffen handelte es sich um eine heissgepresste und zwei gesinterte Siliciumcarbid-Qualitaeten. (orig.)

  17. To increase predictability in complex engineering and fabrication projects : construct of a framework for planning and production control in FMC technologies

    OpenAIRE

    Lia, Knut Anders; Ringerike, Henning

    2014-01-01

    How to increase predictability in complex engineering and fabrication projects is what it is allabout. The case studied, FMC Technologies, is located in Norway, but is part of a globalcompany. FMC has grown quickly, and solving issues with tacit knowledge and personalexperience, as was done earlier, is challenging. The unit of analysis within the organization isthe department of Well Access Systems (WAS). WAS is concerned with connecting subseawells to surface rigs or vessels. A typical proje...

  18. Radiation damage in silicon. Defect analysis and detector properties

    Energy Technology Data Exchange (ETDEWEB)

    Hoenniger, F.

    2008-01-15

    Silicon microstrip and pixel detectors are vital sensor-components as particle tracking detectors for present as well as future high-energy physics (HEP) experiments. All experiments at the large Hadron Collider (LHC) are equipped with such detectors. Also for experiments after the upgrade of the LHC (the so-called Super-LHC), with its ten times higher luminosity, or the planned International Linear Collider (ILC) silicon tracking detectors are forseen. Close to the interaction region these detectors have to face harsh radiation fields with intensities above the presently tolerable level. defect engineering of the used material, e. g. oxygen enrichment of high resistivity float zone silicon and growing of thin low resistivityepitaxial layers on Czochralski silicon substrates has been established to improve the radiation hardness of silicon sensors. This thesis focuses mainly on the investigation of radiation induced defects and their differences observed in various kinds of epitaxial silicon material. Comparisons with other materials like float zone or Czochralski silicon are added. Deep Level Transient Spectroscopy (DLTS) and Thermally Stimulated Current (TSC) measurements have been performed after {gamma}-, electron-, proton- and neutron-irradiation. The differenced in the formation of vacancy and interstitial related defects as well as so-called clustered regions were investigated for various types of irradiation. In addition to the well known defects VO{sub i}, C{sub i}O{sub i}, C{sub i}C{sub s}, VP or V{sub 2} several other defect complexes have been found and investigated. Also the material dependence of the defect introduction rates and the defect annealing behavior has been studied by isothermal and isochronal annealing experiments. Especially the IO{sub 2} defect which is an indicator for the oxygen-dimer content of the material has been investigated in detail. On the basis of radiation induced defects like the bistable donor (BD) defect and a deep

  19. Methods of Si based ceramic components volatilization control in a gas turbine engine

    Science.gov (United States)

    Garcia-Crespo, Andres Jose; Delvaux, John; Dion Ouellet, Noemie

    2016-09-06

    A method of controlling volatilization of silicon based components in a gas turbine engine includes measuring, estimating and/or predicting a variable related to operation of the gas turbine engine; correlating the variable to determine an amount of silicon to control volatilization of the silicon based components in the gas turbine engine; and injecting silicon into the gas turbine engine to control volatilization of the silicon based components. A gas turbine with a compressor, combustion system, turbine section and silicon injection system may be controlled by a controller that implements the control method.

  20. Retrograde Melting and Internal Liquid Gettering in Silicon

    Energy Technology Data Exchange (ETDEWEB)

    Hudelson, Steve; Newman, Bonna K.; Bernardis, Sarah; Fenning, David P.; Bertoni, Mariana I.; Marcus, Matthew A.; Fakra, Sirine C.; Lai, Barry; Buonassisi, Tonio

    2011-07-01

    Retrograde melting (melting upon cooling) is observed in silicon doped with 3d transition metals, via synchrotron-based temperature-dependent X-ray microprobe measurements. Liquid metal-silicon droplets formed via retrograde melting act as efficient sinks for metal impurities dissolved within the silicon matrix. Cooling results in decomposition of the homogeneous liquid phase into solid multiple-metal alloy precipitates. These phenomena represent a novel pathway for engineering impurities in semiconductor-based systems.

  1. Stability of engineered nanomaterials in complex aqueous matrices: Settling behaviour of CeO2 nanoparticles in natural surface waters.

    Science.gov (United States)

    Van Koetsem, Frederik; Verstraete, Simon; Van der Meeren, Paul; Du Laing, Gijs

    2015-10-01

    The stability of engineered nanoparticles (ENPs) in complex aqueous matrices is a key determinant of their fate and potential toxicity towards the aquatic environment and human health. Metal oxide nanoparticles, such as CeO2 ENPs, are increasingly being incorporated into a wide range of industrial and commercial applications, which will undoubtedly result in their (unintentional) release into the environment. Hereby, the behaviour and fate of CeO2 ENPs could potentially serve as model for other nanoparticles that possess similar characteristics. The present study examined the stability and settling of CeO2 ENPs (7.3±1.4 nm) as well as Ce(3+) ions in 10 distinct natural surface waters during 7d, under stagnant and isothermal experimental conditions. Natural water samples were collected throughout Flanders (Belgium) and were thoroughly characterized. For the majority of the surface waters, a substantial depletion (>95%) of the initially added CeO2 ENPs was observed just below the liquid surface of the water samples after 7d. In all cases, the reduction was considerably higher for CeO2 ENPs than for Ce(3+) ions (CeO2 ENPs (R(2)≥0.998) and Ce(3+) ions (R(2)≥0.812) from the water column, at least in case notable sedimentation occurred over time. Solution-pH appeared to be a prime parameter governing nanoparticle colloidal stability. Moreover, the suspended solids (TSS) content also seemed to be an important factor affecting the settling rate and residual fraction of CeO2 ENPs as well as Ce(3+) ions in natural surface waters. Correlation results also suggest potential association and co-precipitation of CeO2 ENPs with aluminium- and iron-containing natural colloidal material. The CeO2 ENPs remained stable in dispersion in surface water characterized by a low pH, ionic strength (IS), and TSS content, indicating the eventual stability and settling behaviour of the nanoparticles was likely determined by a combination of physicochemical parameters. Finally, ionic

  2. Realization of a complex technical and scientific EDP project by means of 'software engineering'

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, B.

    1980-01-01

    The methodics of software engineering used in commercial EDP is applied to a scientific and technical problem. The corresponding approach is shown for the example of numerical calculation of flows through turbomachines.

  3. Robust Environmental Barrier Coatings for Silicon Nitride Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Silicon based ceramics are the leading candidates for the high temperature structural components of the advanced propulsion engines. For such applications, one key...

  4. Engineering tribology

    CERN Document Server

    Stachowiak, Gwidon; Batchelor, A W; Batchelor, Andrew W

    2005-01-01

    As with the previous edition, the third edition of Engineering Tribology provides a thorough understanding of friction and wear using technologies such as lubrication and special materials. Tribology is a complex topic with its own terminology and specialized concepts, yet is vitally important throughout all engineering disciplines, including mechanical design, aerodynamics, fluid dynamics and biomedical engineering. This edition includes updated material on the hydrodynamic aspects of tribology as well as new advances in the field of biotribology, with a focus throughout on the engineering ap

  5. Silicon nitride equation of state

    Science.gov (United States)

    Brown, Robert C.; Swaminathan, Pazhayannur K.

    2017-01-01

    This report presents the development of a global, multi-phase equation of state (EOS) for the ceramic silicon nitride (Si3N4).1 Structural forms include amorphous silicon nitride normally used as a thin film and three crystalline polymorphs. Crystalline phases include hexagonal α-Si3N4, hexagonal β-Si3N4, and the cubic spinel c-Si3N4. Decomposition at about 1900 °C results in a liquid silicon phase and gas phase products such as molecular nitrogen, atomic nitrogen, and atomic silicon. The silicon nitride EOS was developed using EOSPro which is a new and extended version of the PANDA II code. Both codes are valuable tools and have been used successfully for a variety of material classes. Both PANDA II and EOSPro can generate a tabular EOS that can be used in conjunction with hydrocodes. The paper describes the development efforts for the component solid phases and presents results obtained using the EOSPro phase transition model to investigate the solid-solid phase transitions in relation to the available shock data that have indicated a complex and slow time dependent phase change to the c-Si3N4 phase. Furthermore, the EOSPro mixture model is used to develop a model for the decomposition products; however, the need for a kinetic approach is suggested to combine with the single component solid models to simulate and further investigate the global phase coexistences.

  6. Accelerated cross-linking of silicones for liquid-applied sealing of plastic oil pans in the serial production of combustion engines; Beschleunigtes Vernetzen von Silikonen zur Fluessigabdichtung von Oelwannen aus Kunststoff in der Serienproduktion von Verbrennungsmotoren

    Energy Technology Data Exchange (ETDEWEB)

    Preuss, Michael

    2012-07-01

    The author of the contribution under consideration reports on the development of different processes of an accelerated cross-linking of silicones and investigates different sealing concepts for plastic components using a plastic oil pan as an example. Thus, 2K silicones cross-linking at ambient temperature as well as 1K silicones with an accelerated curing due to an additional heat load are developed. The target is an accelerated crosslink of silicones without minimization of the processing period and weakening of the adhesive strength.

  7. EVA thin film with thermo- and moisture-stable luminescent copolymer beads composed of Eu(III) complexes for improvement of energy conversion efficiency on silicon solar cell

    Science.gov (United States)

    Kataoka, Hisataka; Omagari, Shun; Nakanishi, Takayuki; Hasegawa, Yasuchika

    2015-04-01

    Luminescent beads composed of Eu(hfa)3(TPPO)2 (hfa: hexafluoroacetylacetonate, TPPO: triphenylphosphine oxide) in PMMA copolymer (polymethylmethacrylate- styrene and polymethylmethacrylate-trifluoromethylmethacrylate copolymers), PMMA-St-Eu and PMMA-TF-Eu have been reported for improvement of energy conversion efficiency on silicon solar cell. The PMMA-St-Eu and PMMA-TF-Eu beads are prepared using radical initiator AIBN (2,2-azobisisobutyronitrile) without BPO (Benzoyl peroxide) which promotes decomposition of Eu(hfa)3(TPPO)2. The emission properties of EVA (ethylene vinyl acetate) film with PMMA-St-Eu or PMMA-TF-Eu beads are characterized by the emission spectra and lifetimes. Thermo- and moisture-stabilities of the EVA films are performed under high temperature and high moisture condition (85°C85%RH). Increase percentage the solar cell short circuit current efficiency in the solar cell modulation using with EVA film containing PMMA-St-Eu beads with size in 70 μm was estimated to 1.2%. Thermo- and moisture-stable PMMA-St-Eu and PMMA-TF-Eu beads for solar sealing film are demonstrated for the first time.

  8. The Impact of Complex Forcing on the Viscous Torsional Vibration Damper’s Work in the Crankshaft of the Rotating Combustion Engine

    Directory of Open Access Journals (Sweden)

    Jagiełowicz-Ryznar C.

    2016-12-01

    Full Text Available The numerical calculations results of torsional vibration of the multi-cylinder crankshaft in the serial combustion engine (MC, including a viscous damper (VD, at complex forcing, were shown. In fact, in the MC case the crankshaft rotation forcings spectrum is the sum of harmonic forcing whose amplitude can be compared with the amplitude of the 1st harmonic. A significant impact, in the engine operational velocity, on the vibration damping process of MC, may be the amplitude of the 2nd harmonic of a forcing moment. The calculations results of MC vibration, depending on the amplitude of the 2nd harmonic of the forcing moment, for the first form of the torsional vibration, were shown. Higher forms of torsional vibrations have no practical significance. The calculations assume the optimum damping coefficient VD, when the simple harmonic forcing is equal to the base critical velocity of the MC crankshaft.

  9. Atmospheric limiting values for complex hydrocarbon-containing mixtures. Pt. 3. Fuels for combustion engines; Luftgrenzwerte fuer komplexe kohlenwasserstoffhaltige Gemische. T. 3. Kraftstoffe fuer Verbrennungsmotoren

    Energy Technology Data Exchange (ETDEWEB)

    Schwarzer, H.G. [Esso AG, Hamburg (Germany)

    1997-06-01

    The justification paper atmospheric limiting values for complex hydrocarbon-containing mixtures, part 3 - ``fuels for combustion engines`` (gasolines, diesel fuel and kerosene) is currently in preparation. This third part gives information on industrial hygiene regarding the different fuels and describes the application of atmospheric limiting values for fuels. The article offers information on industrial hygiene regarding Otto engine fuel and aviation fuel, which needs to be taken into account in discussions concerning the laying down of atmospheric limiting values. (orig./ABI) [Deutsch] Das Begruendungspapier Luftgrenzwerte fuer komplexe kohlenwasserstoffhaltige Gemische Teil 3 `Kraftstoffe fuer Verbrennungsmotoren` (Gasoline, Dieselkraftstoff und Kerosin) ist z.Z. in Vorbereitung. In diesem dritten Teil werden arbeitshygienische Informationen zu den verschiedenen Kraftstoffen gegeben und die Anwendung der Luftgrenzwerte fuer Kraftstoffe beschrieben. Im folgenden werden arbeitshygienische Informationen zu Ottokraftstoff und Avgas gegeben, die es bei den Ueberlegungen hinsichtlich der Festlegung eines Luftgrenzwertes zu beruecksichtigen gilt. (orig./ABI)

  10. Silicon carbide, an emerging high temperature semiconductor

    Science.gov (United States)

    Matus, Lawrence G.; Powell, J. Anthony

    1991-01-01

    In recent years, the aerospace propulsion and space power communities have expressed a growing need for electronic devices that are capable of sustained high temperature operation. Applications for high temperature electronic devices include development instrumentation within engines, engine control, and condition monitoring systems, and power conditioning and control systems for space platforms and satellites. Other earth-based applications include deep-well drilling instrumentation, nuclear reactor instrumentation and control, and automotive sensors. To meet the needs of these applications, the High Temperature Electronics Program at the Lewis Research Center is developing silicon carbide (SiC) as a high temperature semiconductor material. Research is focussed on developing the crystal growth, characterization, and device fabrication technologies necessary to produce a family of silicon carbide electronic devices and integrated sensors. The progress made in developing silicon carbide is presented, and the challenges that lie ahead are discussed.

  11. Strain-engineered MOSFETs

    CERN Document Server

    Maiti, CK

    2012-01-01

    Currently strain engineering is the main technique used to enhance the performance of advanced silicon-based metal-oxide-semiconductor field-effect transistors (MOSFETs). Written from an engineering application standpoint, Strain-Engineered MOSFETs introduces promising strain techniques to fabricate strain-engineered MOSFETs and to methods to assess the applications of these techniques. The book provides the background and physical insight needed to understand new and future developments in the modeling and design of n- and p-MOSFETs at nanoscale. This book focuses on recent developments in st

  12. Maskless inverted pyramid texturization of silicon.

    Science.gov (United States)

    Wang, Yan; Yang, Lixia; Liu, Yaoping; Mei, Zengxia; Chen, Wei; Li, Junqiang; Liang, Huili; Kuznetsov, Andrej; Xiaolong, Du

    2015-06-02

    We discovered a technical solution of such outstanding importance that it can trigger new approaches in silicon wet etching processing and, in particular, photovoltaic cell manufacturing. The so called inverted pyramid arrays, outperforming conventional pyramid textures and black silicon because of their superior light-trapping and structure characteristics, can currently only be achieved using more complex techniques involving lithography, laser processing, etc. Importantly, our data demonstrate a feasibility of inverted pyramidal texturization of silicon by maskless Cu-nanoparticles assisted etching in Cu(NO3)2 / HF / H2O2 / H2O solutions and as such may have significant impacts on communities of fellow researchers and industrialists.

  13. Efficient gamma-aminobutyric acid bioconversion by employing synthetic complex between glutamate decarboxylase and glutamate/GABA antiporter in engineered Escherichia coli.

    Science.gov (United States)

    Le Vo, Tam Dinh; Ko, Ji-seun; Park, Si Jae; Lee, Seung Hwan; Hong, Soon Ho

    2013-08-01

    Gamma-aminobutyric acid (GABA) is a precursor of one of the most promising heat-resistant biopolymers, Nylon-4, and can be produced by the decarboxylation of monosodium glutamate (MSG). In this study, a synthetic protein complex was applied to improve the GABA conversion in engineered Escherichia coli. Complexes were constructed by assembling a single protein-protein interaction domain SH3 to the glutamate decarboxylase (GadA and GadB) and attaching a cognate peptide ligand to the glutamate/GABA antiporter (GadC) at the N-terminus, C-terminus, and the 233rd amino acid residue. When GadA and GadC were co-overexpressed via the C-terminus complex, a GABA concentration of 5.65 g/l was obtained from 10 g/l MSG, which corresponds to a GABA yield of 93 %. A significant increase of the GABA productivity was also observed where the GABA productivity increased 2.5-fold in the early culture period due to the introduction of the synthetic protein complex. The GABA pathway efficiency and GABA productivity were enhanced by the introduction of the complex between Gad and glutamate/GABA antiporter.

  14. Research on Abrasives in the Chemical Mechanical Polishing Process for Silicon Nitride Balls

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Silicon nitride (Si 3N 4) has been the main material for balls in ceramic ball bearings, for its lower density, high strength, high hardness, fine thermal stability and anticorrosive, and is widely used in various fields, such as high speed and high temperature areojet engines, precision machine tools and chemical engineer machines. Silicon nitride ceramics is a kind of brittle and hard material that is difficult to machining. In the traditional finishing process of silicon nitride balls, balls are lapped...

  15. Fostering Creative Engineers

    DEFF Research Database (Denmark)

    Zhou, Chunfang

    2012-01-01

    Recent studies have argued a shift of thinking about engineering practice from a linear conception to a system understanding. The complexity of engineering practice has been thought of as the root of challenges for engineers. Moreover, creativity has been emphasised as one key capability...... that engineering students should master. This paper aims to illustrate deeply why engineering education needs to foster creative students to face the challenges of complex engineering work. So a literature review will be provided by focusing on the necessity of developing creativity in engineering education....... As the literature demonstrates, this paper reveals the understanding of complexity in engineering practice and the roles of creativity in engineering practice. In addition, the barriers to creativity in current engineering education and some implications of pedagogic strategies will be discussed. So this paper...

  16. Lattice location of transition metals in silicon by means of emission channeling

    CERN Document Server

    da Silva, Daniel José; Wahl, Ulrich; Correia, João Guilherme

    The behavior of transition metals (TMs) in silicon is a subject that has been studied extensively during the last six decades. Their unintentional introduction during the Si production, crystal growth and device manufacturing have made them difficult contaminants to avoid. Once in silicon they easily form deep levels, either when in the isolated form or when forming precipitates. One important effect is the reduction of efficiency of silicon-based devices, being dramatic, in particular, in photovoltaic applications. One way to avoid such effects is by engineering the location of the TM: some TM complexes or lattice sites of the isolated form do not introduce any level in the silicon bandgap. Which point defects lead to such passivation is still under debate. Another way is to mitigate the reduction of efficiency by reducing the dangling bonds of TMs with hydrogen. The most important and commonly used procedures to diminish the unwanted effects of the introduced deep levels are, nevertheless, based on the so-c...

  17. Zwitterionic polymer-modified silicon microring resonators for label-free biosensing in undiluted human plasma.

    Science.gov (United States)

    Kirk, James T; Brault, Norman D; Baehr-Jones, Tom; Hochberg, Michael; Jiang, Shaoyi; Ratner, Daniel M

    2013-04-15

    A widely acknowledged goal in personalized medicine is to radically reduce the costs of highly parallelized, small fluid volume, point-of-care and home-based diagnostics. Recently, there has been a surge of interest in using complementary metal-oxide-semiconductor (CMOS)-compatible silicon photonic circuits for biosensing, with the promise of producing chip-scale integrated devices containing thousands of orthogonal sensors, at minimal cost on a per-chip basis. A central challenge in biosensor translation is to engineer devices that are both sensitive and specific to a target analyte within unprocessed biological fluids. Despite advances in the sensitivity of silicon photonic biosensors, poor biological specificity at the sensor surface remains a significant factor limiting assay performance in complex media (i.e. whole blood, plasma, serum) due to the non-specific adsorption of proteins and other biomolecules. Here, we chemically modify the surface of silicon microring resonator biosensors for the label-free detection of an analyte in undiluted human plasma. This work highlights the first application of a non-fouling zwitterionic surface coating to enable silicon photonic-based label-free detection of a protein analyte at clinically relevant sensitivities in undiluted human plasma.

  18. A rationally engineered yeast pyruvyltransferase Pvg1p introduces sialylation-like properties in neo-human-type complex oligosaccharide.

    Science.gov (United States)

    Higuchi, Yujiro; Yoshinaga, Sho; Yoritsune, Ken-Ichi; Tateno, Hiroaki; Hirabayashi, Jun; Nakakita, Shin-Ichi; Kanekiyo, Miho; Kakuta, Yoshimitsu; Takegawa, Kaoru

    2016-05-19

    Pyruvylation onto the terminus of oligosaccharide, widely seen from prokaryote to eukaryote, confers negative charges on the cell surface and seems to be functionally similar to sialylation, which is found at the end of human-type complex oligosaccharide. However, detailed molecular mechanisms underlying pyruvylation have not been clarified well. Here, we first determined the crystal structure of fission yeast pyruvyltransferase Pvg1p at a resolution of 2.46 Å. Subsequently, by combining molecular modeling with mutational analysis of active site residues, we obtained a Pvg1p mutant (Pvg1p(H168C)) that efficiently transferred pyruvyl moiety onto a human-type complex glycopeptide. The resultant pyruvylated human-type complex glycopeptide recognized similar lectins on lectin arrays as the α2,6-sialyl glycopeptides. This newly-generated pyruvylation of human-type complex oligosaccharides would provide a novel method for glyco-bioengineering.

  19. Engineering interfacial properties by anionic surfactant-chitosan complexes to improve stability of oil-in-water emulsions

    NARCIS (Netherlands)

    Zinoviadou, K.; Scholten, E.; Moschakis, T.; Biliaderis, C.G.

    2012-01-01

    Oil-in-water emulsions (10% w/w n-tetradecane) were prepared at pH = 5.7 by using, as surface active agents, electrostatically formed complexes of sodium stearoyl lactylate (SSL) at a concentration of 0.4% (w/w) and chitosan (CH) in a concentration range between 0 and 0.48% w/w. The use of complexes

  20. Ultra-high speed all-optical signal processing using silicon waveguides and a carbon nanotubes based mode-locked laser

    DEFF Research Database (Denmark)

    Ji, Hua

    This thesis concerns the use of nano-engineered silicon waveguides for ultra-high speed optical serial data signal processing. The fundamental nonlinear properties of nano-engineered silicon waveguides are characterized. Utilizing the nonlinear effect in nano-engineered silicon waveguides...... for demultiplexing of 1.28 Tbit/s optical time division multiplexing data signal is investigated. A sampling system for ultra-high speed signal waveforms based on nano-engineered silicon waveguide is explored. To set up a sampling source, using carbon nanotubes for generating ultra-short pulses is pursued. A silicon...

  1. Flow lines and export lines of Sabalo Gas Field - the engineering of a complex job; Flow lines e export lines de Sabalo - a engenharia da complexidade

    Energy Technology Data Exchange (ETDEWEB)

    Serodio, Conrado Jose Morbach [GDK Engenharia, Salvador, BA (Brazil)

    2003-07-01

    The construction of the natural gas flow lines and export lines system of the Sabalo field, in the far South of Bolivia is an unique job in the pipeline construction area. Its execution is a turning point in terms of engineering and construction technology in this industry. Among the Aguarague Cordillera (mountains), it runs across rocky canyons for more than 5 km, a 2.100 mt long narrow tunnel to overcome the mountains and steep hills along all the ROW length, with a total extension of 70 km, in line pipes ranging from 10'' and 12'' for the flow lines, 28'' for the gas export line and 8' for the condensate line. An integrated construction work plan was settled in order to face and overcome the complex construction situations found in every feet of the pipeline. Four simultaneous work sites were mobilized, 8 independent work fronts, 700 professionals and more than 150 pieces of heavy construction equipment, brought from 3 different countries. Special techniques were adopted also to handle the challenging detail engineering . All in all, the correct conjunction of a sound engineering work, planning, human resources and equipment and the managing flexibility to create alternatives and solutions at the fast pace required by a dynamic work schedule were essential to succeed, in a job with no room for mistakes. The successfully job completion open new possibilities to other challenging projects alike.(author)

  2. Structure of Type IIL Restriction-Modification Enzyme MmeI in Complex with DNA Has Implications for Engineering New Specificities.

    Science.gov (United States)

    Callahan, Scott J; Luyten, Yvette A; Gupta, Yogesh K; Wilson, Geoffrey G; Roberts, Richard J; Morgan, Richard D; Aggarwal, Aneel K

    2016-04-01

    The creation of restriction enzymes with programmable DNA-binding and -cleavage specificities has long been a goal of modern biology. The recently discovered Type IIL MmeI family of restriction-and-modification (RM) enzymes that possess a shared target recognition domain provides a framework for engineering such new specificities. However, a lack of structural information on Type IIL enzymes has limited the repertoire that can be rationally engineered. We report here a crystal structure of MmeI in complex with its DNA substrate and an S-adenosylmethionine analog (Sinefungin). The structure uncovers for the first time the interactions that underlie MmeI-DNA recognition and methylation (5'-TCCRAC-3'; R = purine) and provides a molecular basis for changing specificity at four of the six base pairs of the recognition sequence (5'-TCCRAC-3'). Surprisingly, the enzyme is resilient to specificity changes at the first position of the recognition sequence (5'-TCCRAC-3'). Collectively, the structure provides a basis for engineering further derivatives of MmeI and delineates which base pairs of the recognition sequence are more amenable to alterations than others.

  3. Engineering Science, Skills, and Bildung

    DEFF Research Database (Denmark)

    Christensen, Jens

    The background for the book is a quest for a thorough analysis of engineering, engineering science, and engineering education. Focusing on the concepts of engineering science, skills, and Bildung, the book investigates the real challenges that are confronting engineering today, and discusses how...... to respond to these. Thereby, the book offers a complex and nuanced basis for debates on the actual status and the future directions of engineering science, engineering education, and the everyday practice of engineers....

  4. Doping Silicon Wafers with Boron by Use of Silicon Paste

    Institute of Scientific and Technical Information of China (English)

    Yu Gao; Shu Zhou; Yunfan Zhang; Chen Dong; Xiaodong Pi; Deren Yang

    2013-01-01

    In this work we introduce recently developed silicon-paste-enabled p-type doping for silicon.Boron-doped silicon nanoparticles are synthesized by a plasma approach.They are then dispersed in solvents to form silicon paste.Silicon paste is screen-printed at the surface of silicon wafers.By annealing,boron atoms in silicon paste diffuse into silicon wafers.Chemical analysis is employed to obtain the concentrations of boron in silicon nanoparticles.The successful doping of silicon wafers with boron is evidenced by secondary ion mass spectroscopy (SIMS) and sheet resistance measurements.

  5. Emotional engineering

    CERN Document Server

    In an age of increasing complexity, diversification and change, customers expect services that cater to their needs and to their tastes. Emotional Engineering vol 2. describes how their expectations can be satisfied and managed throughout the product life cycle, if producers focus their attention more on emotion. Emotional engineering provides the means to integrate products to create a new social framework and develops services beyond product realization to create of value across a full lifetime.  14 chapters cover a wide range of topics that can be applied to product, process and industry development, with special attention paid to the increasing importance of sensing in the age of extensive and frequent changes, including: • Multisensory stimulation and user experience  • Physiological measurement • Tactile sensation • Emotional quality management • Mental model • Kansei engineering.   Emotional Engineering vol 2 builds on Dr Fukuda’s previous book, Emotional Engineering, and provides read...

  6. OCULAR COMPLICATIONS OF SILICONE OIL

    Directory of Open Access Journals (Sweden)

    Muhammad Kamran Khalid

    2016-06-01

    Full Text Available Objective: Silicone oil (SO is an invaluable tool in the management of complex retinal detachments (RDs. Injection of silicone oil is associated with a variety of ocular complications specially when it is kept for a long time and its removal is endangering retinal re-detachment. The objective of this study was to determine the frequencies of different ocular complications associated with silicone oil injection in our setup. Study Design: Case series. Place and Duration of Study: This study was conducted at Vitreo-retina division of Al-Shifa Trust Eye Hospital, Rawalpindi from January 2014 to June 2014. Material and Methods: A total of 30 patients were included in the study who underwent pars-planavitrectomy (PPV with silicone oil injection for complex retinal detachments. The patients who had reached between 3 months & 6 months of their postoperative period and were presenting with some complications related to silicone oil injection were included in the study. Their records were reviewed and pre-operative data were collected regarding state of the eye preoperatively. Then the post-operative complications were noted. The descriptive and analytical statistics of different variables were measured using SPSS-17.0 software. Results: Out of thirty patients included in our study 23 (76.7% were male and 7 (23.3% were female. The mean age was 21.53 ± 16.004 years and range was 66 years. The mean pre-operative intra-ocular pressure ( IOP was 14.0 ± 2.150 mmHg and range 8 mmHg and the mean post-operative IOP was 24.93 ± 13.889 mmHg and range 45 mmHg (p=0.001. The pre-operative PVR grade-C was absent in 12 (40% patients and was present in 18 (60% patients and post-operative PVR grade-C was absent in 24 (80% patients and was present in 6 (20% patients (p=0.004; McNemar test. Band keratopathy was seen in 8 (26.7% and corneal decompensation in 2 (6.7% patients. Emulsification of silicone oil was seen in 14 (46.7% patients. Rubeosisiridis was present in 2

  7. Silicon: electrochemistry and luminescence

    NARCIS (Netherlands)

    Kooij, Ernst Stefan

    1997-01-01

    The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible luminescenc

  8. Silicon: electrochemistry and luminescence

    NARCIS (Netherlands)

    Kooij, Ernst Stefan

    1997-01-01

    The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible

  9. Silicon: electrochemistry and luminescence

    NARCIS (Netherlands)

    Kooij, Ernst Stefan

    2001-01-01

    The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible luminescenc

  10. Graphitized silicon carbide microbeams: wafer-level, self-aligned graphene on silicon wafers.

    Science.gov (United States)

    Cunning, Benjamin V; Ahmed, Mohsin; Mishra, Neeraj; Kermany, Atieh Ranjbar; Wood, Barry; Iacopi, Francesca

    2014-08-15

    Currently proven methods that are used to obtain devices with high-quality graphene on silicon wafers involve the transfer of graphene flakes from a growth substrate, resulting in fundamental limitations for large-scale device fabrication. Moreover, the complex three-dimensional structures of interest for microelectromechanical and nanoelectromechanical systems are hardly compatible with such transfer processes. Here, we introduce a methodology for obtaining thousands of microbeams, made of graphitized silicon carbide on silicon, through a site-selective and wafer-scale approach. A Ni-Cu alloy catalyst mediates a self-aligned graphitization on prepatterned SiC microstructures at a temperature that is compatible with silicon technologies. The graphene nanocoating leads to a dramatically enhanced electrical conductivity, which elevates this approach to an ideal method for the replacement of conductive metal films in silicon carbide-based MEMS and NEMS devices.

  11. Sampling Artifacts from Conductive Silicone Tubing

    Energy Technology Data Exchange (ETDEWEB)

    Timko, Michael T.; Yu, Zhenhong; Kroll, Jesse; Jayne, John T.; Worsnop, Douglas R.; Miake-Lye, Richard C.; Onasch, Timothy B.; Liscinsky, David; Kirchstetter, Thomas W.; Destaillats, Hugo; Holder, Amara L.; Smith, Jared D.; Wilson, Kevin R.

    2009-05-15

    We report evidence that carbon impregnated conductive silicone tubing used in aerosol sampling systems can introduce two types of experimental artifacts: 1) silicon tubing dynamically absorbs carbon dioxide gas, requiring greater than 5 minutes to reach equilibrium and 2) silicone tubing emits organic contaminants containing siloxane that adsorb onto particles traveling through it and onto downstream quartz fiber filters. The consequence can be substantial for engine exhaust measurements as both artifacts directly impact calculations of particulate mass-based emission indices. The emission of contaminants from the silicone tubing can result in overestimation of organic particle mass concentrations based on real-time aerosol mass spectrometry and the off-line thermal analysis of quartz filters. The adsorption of siloxane contaminants can affect the surface properties of aerosol particles; we observed a marked reduction in the water-affinity of soot particles passed through conductive silicone tubing. These combined observations suggest that the silicone tubing artifacts may have wide consequence for the aerosol community and should, therefore, be used with caution. Gentle heating, physical and chemical properties of the particle carriers, exposure to solvents, and tubing age may influence siloxane uptake. The amount of contamination is expected to increase as the tubing surface area increases and as the particle surface area increases. The effect is observed at ambient temperature and enhanced by mild heating (<100 oC). Further evaluation is warranted.

  12. Software engineering as an engineering discipline

    Science.gov (United States)

    Freedman, Glenn B.

    1988-01-01

    The purpose of this panel is to explore the emerging field of software engineering from a variety of perspectives: university programs; industry training and definition; government development; and technology transfer. In doing this, the panel will address the issues of distinctions among software engineering, computer science, and computer hardware engineering as they relate to the challenges of large, complex systems.

  13. Seeing around a Ball: Complex, Technology-Based Problems in Calculus with Applications in Science and Engineering-Redux

    Science.gov (United States)

    Winkel, Brian

    2008-01-01

    A complex technology-based problem in visualization and computation for students in calculus is presented. Strategies are shown for its solution and the opportunities for students to put together sequences of concepts and skills to build for success are highlighted. The problem itself involves placing an object under water in order to actually see…

  14. Game-Theory-Based Search Engine to Automate the Mass Assignment in Complex Native Electrospray Mass Spectra

    NARCIS (Netherlands)

    Tseng, Y.H.; Uetrecht, C.; Yang, S.C.; Barendregt, A.; Heck, A.J.R.; Peng, W.P.

    2013-01-01

    Electrospray ionization coupled to native mass spectrometry (MS) has evolved into an important tool in structural biology to decipher the composition of protein complexes. However, the mass analysis of heterogeneous protein assemblies is hampered because of their overlapping charge state distributio

  15. A brief review of recent developments in the designs that prevent bio-fouling on silicon and silicon-based materials.

    Science.gov (United States)

    Zhang, Xiaoning; Brodus, DaShan; Hollimon, Valerie; Hu, Hongmei

    2017-01-01

    Silicon and silicon-based materials are essential to our daily life. They are widely used in healthcare and manufacturing. However, silicon and silicon-based materials are susceptible to bio-fouling, which is of great concern in numerous applications. To date, interdisciplinary research in surface science, polymer science, biology, and engineering has led to the implementation of antifouling strategies for silicon-based materials. However, a review to discuss those antifouling strategies for silicon-based materials is lacking. In this article, we summarized two major approaches involving the functionalization of silicon and silicon-based materials with molecules exhibiting antifouling properties, and the fabrication of silicon-based materials with nano- or micro-structures. Both approaches lead to a significant reduction in bio-fouling. We critically reviewed the designs that prevent fouling due to proteins, bacteria, and marine organisms on silicon and silicon-based materials. Graphical abstractStrategies used in the designs that prevent bio-fouling on silicon and silicon-based materials.

  16. Applied and engineering versions of the theory of elastoplastic processes of active complex loading part 2: Identification and verification

    Science.gov (United States)

    Peleshko, V. A.

    2016-06-01

    The deviator constitutive relation of the proposed theory of plasticity has a three-term form (the stress, stress rate, and strain rate vectors formed from the deviators are collinear) and, in the specialized (applied) version, in addition to the simple loading function, contains four dimensionless constants of the material determined from experiments along a two-link strain trajectory with an orthogonal break. The proposed simple mechanism is used to calculate the constants of themodel for four metallic materials that significantly differ in the composition and in the mechanical properties; the obtained constants do not deviate much from their average values (over the four materials). The latter are taken as universal constants in the engineering version of the model, which thus requires only one basic experiment, i. e., a simple loading test. If the material exhibits the strengthening property in cyclic circular deformation, then the model contains an additional constant determined from the experiment along a strain trajectory of this type. (In the engineering version of the model, the cyclic strengthening effect is not taken into account, which imposes a certain upper bound on the difference between the length of the strain trajectory arc and the module of the strain vector.) We present the results of model verification using the experimental data available in the literature about the combined loading along two- and multi-link strain trajectories with various lengths of links and angles of breaks, with plane curvilinear segments of various constant and variable curvature, and with three-dimensional helical segments of various curvature and twist. (All in all, we use more than 80 strain programs; the materials are low- andmedium-carbon steels, brass, and stainless steel.) These results prove that the model can be used to describe the process of arbitrary active (in the sense of nonnegative capacity of the shear) combine loading and final unloading of originally

  17. Nanoscale plasmonic stamp lithography on silicon.

    Science.gov (United States)

    Liu, Fenglin; Luber, Erik J; Huck, Lawrence A; Olsen, Brian C; Buriak, Jillian M

    2015-02-24

    Nanoscale lithography on silicon is of interest for applications ranging from computer chip design to tissue interfacing. Block copolymer-based self-assembly, also called directed self-assembly (DSA) within the semiconductor industry, can produce a variety of complex nanopatterns on silicon, but these polymeric films typically require transformation into functional materials. Here we demonstrate how gold nanopatterns, produced via block copolymer self-assembly, can be incorporated into an optically transparent flexible PDMS stamp, termed a plasmonic stamp, and used to directly functionalize silicon surfaces on a sub-100 nm scale. We propose that the high intensity electric fields that result from the localized surface plasmons of the gold nanoparticles in the plasmonic stamps upon illumination with low intensity green light, lead to generation of electron-hole pairs in the silicon that drive spatially localized hydrosilylation. This approach demonstrates how localized surface plasmons can be used to enable functionalization of technologically relevant surfaces with nanoscale control.

  18. Chemical Analysis Methods for Silicon Carbide

    Institute of Scientific and Technical Information of China (English)

    Shen Keyin

    2006-01-01

    @@ 1 General and Scope This Standard specifies the determination method of silicon dioxide, free silicon, free carbon, total carbon, silicon carbide, ferric sesquioxide in silicon carbide abrasive material.

  19. Glass-silicon column

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Conrad M.

    2003-12-30

    A glass-silicon column that can operate in temperature variations between room temperature and about 450.degree. C. The glass-silicon column includes large area glass, such as a thin Corning 7740 boron-silicate glass bonded to a silicon wafer, with an electrode embedded in or mounted on glass of the column, and with a self alignment silicon post/glass hole structure. The glass/silicon components are bonded, for example be anodic bonding. In one embodiment, the column includes two outer layers of silicon each bonded to an inner layer of glass, with an electrode imbedded between the layers of glass, and with at least one self alignment hole and post arrangement. The electrode functions as a column heater, and one glass/silicon component is provided with a number of flow channels adjacent the bonded surfaces.

  20. Porous silicon gettering

    Energy Technology Data Exchange (ETDEWEB)

    Tsuo, Y.S.; Menna, P.; Al-Jassim, M. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1995-08-01

    We have studied a novel extrinsic gettering method that utilizes the very large surface areas, produced by porous silicon etch on both front and back surfaces of the silicon wafer, as gettering sites. In this method, a simple and low-cost chemical etching is used to generate the porous silicon layers. Then, a high-flux solar furnace (HFSF) is used to provide high-temperature annealing and the required injection of silicon interstitials. The gettering sites, along with the gettered impurities, can be easily removed at the end the process. The porous silicon removal process consists of oxidizing the porous silicon near the end the gettering process followed by sample immersion in HF acid. Each porous silicon gettering process removes up to about 10 {mu}m of wafer thickness. This gettering process can be repeated so that the desired purity level is obtained.

  1. Mid-infrared nonlinear silicon photonics

    Science.gov (United States)

    Liu, Xiaoping; Kuyken, Bart; Green, William M. J.; Osgood, Richard M.; Baets, Roel; Roelkens, Gunther

    2014-03-01

    Recently there has been a growing interest in mid-infrared (mid-IR) photonic technology with a wavelength of operation approximately from 2-14 μm. Among several established mid-IR photonic platforms, silicon nanophotonic platform could potentially offer ultra-compact, and monolithically integrated mid-IR photonic devices and device arrays, which could have board impact in the mid-IR technology, such as molecular spectroscopy, and imaging. At room temperature, silicon has a bandgap ~ 1.12 eV resulting in vanishing two-photon absorption (TPA) for mid-IR wavelengths beyond 2.2 μm, which, coupled with silicon's large nonlinear index of refraction and its strong waveguide optical confinement, enables efficient nonlinear processes in the mid-IR. By taking advantage of these nonlinear processes and judicious dispersion engineering in silicon waveguides, we have recently demonstrated a handful of silicon mid-IR nonlinear components, including optical parametric amplifiers (OPA), broadband sources, and a wavelength translator. Silicon nanophotonic waveguide's anomalous dispersion design, providing four-wave-mixing (FWM) phase-matching, has enabled the first demonstration of silicon mid-IR optical parametric amplifier (OPA) with a net off-chip gain exceeding 13 dB. In addition, reduction of propagation losses and balanced second and fourth order waveguide dispersion design led to an OPA with an extremely broadband gain spectrum from 1.9-2.5 μm and >50 dB parametric gain, upon which several novel silicon mid-IR light sources were built, including a mid-IR optical parametric oscillator, and a supercontinuum source. Finally, a mid-IR wavelength translation device, capable of translating signals near 2.4 μm to the telecom-band near 1.6 μm with simultaneous 19 dB gain, was demonstrated.

  2. Preparation and chemical and biological characterization of a pectin/chitosan polyelectrolyte complex scaffold for possible bone tissue engineering applications.

    Science.gov (United States)

    Coimbra, P; Ferreira, P; de Sousa, H C; Batista, P; Rodrigues, M A; Correia, I J; Gil, M H

    2011-01-01

    In this work, porous scaffolds obtained from the freeze-drying of pectin/chitosan polyelectrolyte complexes were prepared and characterized by FTIR, SEM and weight loss studies. Additionally, the cytotoxicity of the prepared scaffolds was evaluated in vitro, using human osteoblast cells. The results obtained showed that cells adhered to scaffolds and proliferated. The study also confirmed that the degradation by-products of pectin/chitosan scaffold are noncytotoxic.

  3. Silicon photonics: some remaining challenges

    Science.gov (United States)

    Reed, G. T.; Topley, R.; Khokhar, A. Z.; Thompson, D. J.; Stanković, S.; Reynolds, S.; Chen, X.; Soper, N.; Mitchell, C. J.; Hu, Y.; Shen, L.; Martinez-Jimenez, G.; Healy, N.; Mailis, S.; Peacock, A. C.; Nedeljkovic, M.; Gardes, F. Y.; Soler Penades, J.; Alonso-Ramos, C.; Ortega-Monux, A.; Wanguemert-Perez, G.; Molina-Fernandez, I.; Cheben, P.; Mashanovich, G. Z.

    2016-03-01

    This paper discusses some of the remaining challenges for silicon photonics, and how we at Southampton University have approached some of them. Despite phenomenal advances in the field of Silicon Photonics, there are a number of areas that still require development. For short to medium reach applications, there is a need to improve the power consumption of photonic circuits such that inter-chip, and perhaps intra-chip applications are viable. This means that yet smaller devices are required as well as thermally stable devices, and multiple wavelength channels. In turn this demands smaller, more efficient modulators, athermal circuits, and improved wavelength division multiplexers. The debate continues as to whether on-chip lasers are necessary for all applications, but an efficient low cost laser would benefit many applications. Multi-layer photonics offers the possibility of increasing the complexity and effectiveness of a given area of chip real estate, but it is a demanding challenge. Low cost packaging (in particular, passive alignment of fibre to waveguide), and effective wafer scale testing strategies, are also essential for mass market applications. Whilst solutions to these challenges would enhance most applications, a derivative technology is emerging, that of Mid Infra-Red (MIR) silicon photonics. This field will build on existing developments, but will require key enhancements to facilitate functionality at longer wavelengths. In common with mainstream silicon photonics, significant developments have been made, but there is still much left to do. Here we summarise some of our recent work towards wafer scale testing, passive alignment, multiplexing, and MIR silicon photonics technology.

  4. Aligned carbon nanotube-silicon sheets: a novel nano-architecture for flexible lithium ion battery electrodes.

    Science.gov (United States)

    Fu, Kun; Yildiz, Ozkan; Bhanushali, Hardik; Wang, Yongxin; Stano, Kelly; Xue, Leigang; Zhang, Xiangwu; Bradford, Philip D

    2013-09-25

    Aligned carbon nanotube sheets provide an engineered scaffold for the deposition of a silicon active material for lithium ion battery anodes. The sheets are low-density, allowing uniform deposition of silicon thin films while the alignment allows unconstrained volumetric expansion of the silicon, facilitating stable cycling performance. The flat sheet morphology is desirable for battery construction.

  5. Impurities in silicon and their impact on solar cell performance

    NARCIS (Netherlands)

    Coletti, Gianluca

    2011-01-01

    Photovoltaic conversion of solar energy is a rapidly growing technology. More than 80% of global solar cell production is currently based on silicon. The aim of this thesis is to understand the complex relation between impurity content of silicon starting material (“feedstock”) and the resulting sol

  6. Jaguar Procedures for Detonation Behavior of Silicon Containing Explosives

    Science.gov (United States)

    Stiel, L. I.; Baker, E. L.; Capellos, C.; Poulos, W.

    2007-12-01

    Improved relationships were developed in this study for the thermodynamic properties of solid and liquid silicon and silicon dioxide for use with JAGUAR thermo-chemical equation of state routines. Analyses of experimental melting temperature curves for silicon and silicon dioxide indicated complex phase behavior and that improved coefficients were required for solid and liquid thermodynamic properties. Advanced optimization routines were utilized in conjunction with the experimental melting point data to establish volumetric coefficients for these substances. The new property libraries resulted in agreement with available experimental values, including Hugoniot data at elevated pressures.

  7. Dendritic cells engineered to express defined allo-HLA peptide complexes induce antigen-specific cytotoxic T cells efficiently killing tumour cells

    DEFF Research Database (Denmark)

    Stronen, E; Abrahamsen, I W; Gaudernack, G;

    2009-01-01

    presented by a non-self human leucocyte antigen (HLA) molecule and transferred to cancer patients expressing that HLA molecule. Obtaining allo-restricted CTL of high-avidity and low cross-reactivity has, however, proven difficult. Here, we show that dendritic cells transfected with mRNA encoding HLA-A*0201...... and efficiently killed HLA-A*0201(+) melanoma cells, whilst sparing HLA-A*0201(+) B-cells. Allo-restricted CTL specific for peptides from the leukaemia-associated antigens CD33 and CD19 were obtained with comparable efficiency. Collectively, the results show that dendritic cells engineered to express defined allo......Most tumour-associated antigens (TAA) are non-mutated self-antigens. The peripheral T cell repertoire is devoid of high-avidity TAA-specific cytotoxic T lymphocytes (CTL) due to self-tolerance. As tolerance is major histocompatibility complex-restricted, T cells may be immunized against TAA...

  8. Integrating engineering principles into the medico-legal investigation of a rare fatal rollover car accident involving complex dynamics.

    Science.gov (United States)

    Grassi, Vincenzo M; Castagnola, Flaminia; Miscusi, Massimo; De-Giorgio, Fabio

    2016-09-01

    Rollover car accidents can be the result of forceful steering or hitting an obstacle that acts like a ramp. Mortality from this type of car accident is particularly high, especially when occupants are thrown out of the vehicle. We report a case of a 67-year-old man who died after a rollover accident that occurred when he was driving a car equipped with a glass moonroof. He was found inside his car with his safety belt correctly fastened and the roof shattered. At autopsy, a wide avulsion injury of the head was observed, which was associated with an atlanto-axial dislocation and full-thickness fracture of the cervical body and posterior facet joints of the seventh cervical vertebra. The data collected at the scene of the accident were integrated with the autopsy results to yield a forensic engineering reconstruction. This reconstruction elucidated the dynamics of the event and correctly ascribed the lesions observed at autopsy to the phases of the rollover. Afterward, an analysis of the scientific literature concerning rollover crash tests was conducted to understand why the driver sustained fatal injuries even though his seatbelt was properly fastened.

  9. The government and the problems of development of non-governmental enterprises of the military-industrial complex and civil engineering of Russia

    Directory of Open Access Journals (Sweden)

    Aleksandr Vladimirovich Lugovtsov

    2012-09-01

    Full Text Available The non-governmental industrial sector of Russia is growing from year to year as a result of privatization program consistently held by the government. In the beginning of the 90-s, the heads of state have decided not to hold the state industrial policy any more reasoning from the idea of market self-regulation. The enterprises of the military-industrial complex of Russia, as a result, were in a grave condition because there were no state orders anymore. The enterprises were offered to produce civil engineering production because it was considered that there were no more enemies to fight against. As time goes by, some enterprises became bankrupt. But the majority has survived under the direction of smart owners despite but not due to the conditions of survival of that time. The life has shown that the state industrial policy is indispensable, especially when Russia is near to enter into the WTO. There are no more obstacles on the path to this, but nobody knowsexactly which enterprises will become bankrupt, what will be with those people who will lose their work and which enterprises will continue working and how. It is not clear neither at federal level nor at regional or municipal. In this paper, the modern operating conditions and opportunities to modernize the non-governmental industrial sector are analyzed. Performatives on education reform regarding the young engineers and economists aimed to reduce the period of their adaptation at work have been formulated.

  10. Engineering Ontologies

    NARCIS (Netherlands)

    Borst, Pim; Akkermans, Hans; Top, Jan

    1997-01-01

    We analyse the construction as well as the role of ontologies in knowledge sharing and reuse for complex industrial applications. In this article, the practical use of ontologies in large-scale applications not restricted to knowledge-based systems is demonstrated, for the domain of engineering syst

  11. Detection, characterization and quantification of inorganic engineered nanomaterials: A review of techniques and methodological approaches for the analysis of complex samples.

    Science.gov (United States)

    Laborda, Francisco; Bolea, Eduardo; Cepriá, Gemma; Gómez, María T; Jiménez, María S; Pérez-Arantegui, Josefina; Castillo, Juan R

    2016-01-21

    The increasing demand of analytical information related to inorganic engineered nanomaterials requires the adaptation of existing techniques and methods, or the development of new ones. The challenge for the analytical sciences has been to consider the nanoparticles as a new sort of analytes, involving both chemical (composition, mass and number concentration) and physical information (e.g. size, shape, aggregation). Moreover, information about the species derived from the nanoparticles themselves and their transformations must also be supplied. Whereas techniques commonly used for nanoparticle characterization, such as light scattering techniques, show serious limitations when applied to complex samples, other well-established techniques, like electron microscopy and atomic spectrometry, can provide useful information in most cases. Furthermore, separation techniques, including flow field flow fractionation, capillary electrophoresis and hydrodynamic chromatography, are moving to the nano domain, mostly hyphenated to inductively coupled plasma mass spectrometry as element specific detector. Emerging techniques based on the detection of single nanoparticles by using ICP-MS, but also coulometry, are in their way to gain a position. Chemical sensors selective to nanoparticles are in their early stages, but they are very promising considering their portability and simplicity. Although the field is in continuous evolution, at this moment it is moving from proofs-of-concept in simple matrices to methods dealing with matrices of higher complexity and relevant analyte concentrations. To achieve this goal, sample preparation methods are essential to manage such complex situations. Apart from size fractionation methods, matrix digestion, extraction and concentration methods capable of preserving the nature of the nanoparticles are being developed. This review presents and discusses the state-of-the-art analytical techniques and sample preparation methods suitable for

  12. Silicon Photonics II Components and Integration

    CERN Document Server

    Lockwood, David J

    2011-01-01

    This book is volume II of a series of books on silicon photonics. It gives a fascinating picture of the state-of-the-art in silicon photonics from a component perspective. It presents a perspective on what can be expected in the near future. It is formed from a selected number of reviews authored by world leaders in the field, and is written from both academic and industrial viewpoints. An in-depth discussion of the route towards fully integrated silicon photonics is presented. This book will be useful not only to physicists, chemists, materials scientists, and engineers but also to graduate students who are interested in the fields of micro- and nanophotonics and optoelectronics.

  13. A Novel Nanofabrication Technique of Silicon-Based Nanostructures

    Science.gov (United States)

    Meng, Lingkuan; He, Xiaobin; Gao, Jianfeng; Li, Junjie; Wei, Yayi; Yan, Jiang

    2016-11-01

    A novel nanofabrication technique which can produce highly controlled silicon-based nanostructures in wafer scale has been proposed using a simple amorphous silicon (α-Si) material as an etch mask. SiO2 nanostructures directly fabricated can serve as nanotemplates to transfer into the underlying substrates such as silicon, germanium, transistor gate, or other dielectric materials to form electrically functional nanostructures and devices. In this paper, two typical silicon-based nanostructures such as nanoline and nanofin have been successfully fabricated by this technique, demonstrating excellent etch performance. In addition, silicon nanostructures fabricated above can be further trimmed to less than 10 nm by combing with assisted post-treatment methods. The novel nanofabrication technique will be expected a new emerging technology with low process complexity and good compatibility with existing silicon integrated circuit and is an important step towards the easy fabrication of a wide variety of nanoelectronics, biosensors, and optoelectronic devices.

  14. SILICON CARBIDE FOR SEMICONDUCTORS

    Science.gov (United States)

    This state-of-the-art survey on silicon carbide for semiconductors includes a bibliography of the most important references published as of the end...of 1964. The various methods used for growing silicon carbide single crystals are reviewed, as well as their properties and devices fabricated from...them. The fact that the state of-the-art of silicon carbide semiconductors is not further advanced may be attributed to the difficulties of growing

  15. Silicon Carbide Shapes.

    Science.gov (United States)

    Free-standing silicon carbide shapes are produced by passing a properly diluted stream of a reactant gas, for example methyltrichlorosilane, into a...reaction chamber housing a thin walled, hollow graphite body heated to 1300-1500C. After the graphite body is sufficiently coated with silicon carbide , the...graphite body is fired, converting the graphite to gaseous CO2 and CO and leaving a silicon carbide shaped article remaining.

  16. Quenching Capabilities of Long-Chain Carotenoids in Light-Harvesting-2 Complexes from Rhodobacter sphaeroides with an Engineered Carotenoid Synthesis Pathway.

    Science.gov (United States)

    Dilbeck, Preston L; Tang, Qun; Mothersole, David J; Martin, Elizabeth C; Hunter, C Neil; Bocian, David F; Holten, Dewey; Niedzwiedzki, Dariusz M

    2016-06-23

    Six light-harvesting-2 complexes (LH2) from genetically modified strains of the purple photosynthetic bacterium Rhodobacter (Rb.) sphaeroides were studied using static and ultrafast optical methods and resonance Raman spectroscopy. These strains were engineered to incorporate carotenoids for which the number of conjugated groups (N = NC═C + NC═O) varies from 9 to 15. The Rb. sphaeroides strains incorporate their native carotenoids spheroidene (N = 10) and spheroidenone (N = 11), as well as longer-chain analogues including spirilloxanthin (N = 13) and diketospirilloxantion (N = 15) normally found in Rhodospirillum rubrum. Measurements of the properties of the carotenoid first singlet excited state (S1) in antennas from the Rb. sphaeroides set show that carotenoid-bacteriochlorophyll a (BChl a) interactions are similar to those in LH2 complexes from various other bacterial species and thus are not significantly impacted by differences in polypeptide composition. Instead, variations in carotenoid-to-BChl a energy transfer are primarily regulated by the N-determined energy of the carotenoid S1 excited state, which for long-chain (N ≥ 13) carotenoids is not involved in energy transfer. Furthermore, the role of the long-chain carotenoids switches from a light-harvesting supporter (via energy transfer to BChl a) to a quencher of the BChl a S1 excited state B850*. This quenching is manifested as a substantial (∼2-fold) reduction of the B850* lifetime and the B850* fluorescence quantum yield for LH2 housing the longest carotenoids.

  17. Historic American engineering record. Nevada national security site, Bren Tower Complex. Written historical and descriptive data and field records

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Susan R. [Desert Research Institute, Las Vegas, NV (United States); Goldenberg, Nancy [Carey & Co Inc., San Francisco, CA (United States)

    2013-08-01

    The BREN (Bare Reactor Experiment, Nevada) Tower Complex is significant for its role in the history of nuclear testing, radiation dosimetry studies, and early field testing of the Strategic Missile Defense System designs. At the time it was built in 1962, the 1,527 ft (465 m) BREN Tower was the tallest structure west of the Mississippi River and exceeded the height of the Empire State Building by 55 ft (17 m). It remains the tallest ever erected specifically for scientific purposes and was designed and built to facilitate the experimental dosimetry studies necessary for the development of accurate radiation dose rates for the survivors of Hiroshima and Nagasaki. The tower was a key component of the Atomic Bomb Casualty Commission’s (ABCC) mission to predict the health effects of radiation exposure. Moved to its current location in 1966, the crucial dosimetry studies continued with Operation HENRE (High Energy Neutron Reactions Experiment). These experiments and the data they generated became the basis for a dosimetry system called the Tentative 1965 Dose or more commonly the T65D model. Used to estimate radiation doses received by individuals, the T65D model was applied until the mid-1980s when it was replaced by a new dosimetry system known as DS86 based on the Monte Carlo method of dose rate calculation. However, the BREN Tower data are still used for verification of the validity of the DS86 model. In addition to its importance in radiation heath effects research, the BREN Tower Complex is also significant for its role in the Brilliant Pebbles research project, a major component of the Strategic Defense Initiative popularly known as the “Star Wars” Initiative. Instigated under the Reagan Administration, the program’s purpose was to develop a system to shield the United States and allies from a ballistic missile attack. The centerpiece of the Strategic Defense System was space-based, kinetic-kill vehicles. In 1991, BREN Tower was used for the tether tests

  18. Electrical Spin-Injection into Silicon and Spin FET

    Science.gov (United States)

    2010-02-18

    MgO/silicon tunneling emitter NPN bipolar transistors . Device simulations revealed that the NDTC was the consequence of an inversion layer at...2009. He is now a research engineer at Intel Semiconductor Company. The aim of the project was to explore a tunneling emitter bipolar transistor as a...possible spin injector into silicon, and we have succeeded in that goal. The transistor has a metallic emitter that as a spin-injector will be a 1

  19. Novel Silicon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Novel silicon nanotubes with inner-diameter of 60-80 nm was prepared using hydrogen-added dechlorination of SiCl4 followed by chemical vapor deposition (CVD) on a NixMgyO catalyst. The TEM observation showed that the suitable reaction temperature is 973 K for the formation of silicon nanotubes. Most of silicon nanotubes have one open end and some have two closed ends. The shape ofnanoscale silicon, however, is a micro-crystal type at 873 K, a rod or needle type at 993 K and an onion-type at 1023 K, respectively.

  20. Nonlinear Silicon Photonic Signal Processing Devices for Future Optical Networks

    Directory of Open Access Journals (Sweden)

    Cosimo Lacava

    2017-01-01

    Full Text Available In this paper, we present a review on silicon-based nonlinear devices for all optical nonlinear processing of complex telecommunication signals. We discuss some recent developments achieved by our research group, through extensive collaborations with academic partners across Europe, on optical signal processing using silicon-germanium and amorphous silicon based waveguides as well as novel materials such as silicon rich silicon nitride and tantalum pentoxide. We review the performance of four wave mixing wavelength conversion applied on complex signals such as Differential Phase Shift Keying (DPSK, Quadrature Phase Shift Keying (QPSK, 16-Quadrature Amplitude Modulation (QAM and 64-QAM that dramatically enhance the telecom signal spectral efficiency, paving the way to next generation terabit all-optical networks.

  1. Breast Implants: Saline vs. Silicone

    Science.gov (United States)

    ... differ in material and consistency, however. Saline breast implants Saline implants are filled with sterile salt water. ... of any age for breast reconstruction. Silicone breast implants Silicone implants are pre-filled with silicone gel — ...

  2. Dialectical thinking in engineering management

    Institute of Scientific and Technical Information of China (English)

    Yang Shanlint; Huang Zhibin; Ren Xueping

    2012-01-01

    Modem engineering management activities have all become more complex, being far beyond the economic and technological areas, due to their growing grand scales, increasingly complex structures and integrated systems. Therefore, we need focus our attention on engineering management activities by resorting to dialectical thinking and take full account of them based on the height of the new era. This paper described and analyzed engineering management activities from the following 5 aspects : the cyclic promotion between engineering management theory and engineering management practice, the in-depth integration of engineering management concepts with engineering management methods, the coordinated harmonization of engineering management system with engineering management details, the mutual promotion between engineering management standardization and engineering management innovation, the common enhancement between engineering management team and engineering management system.

  3. Soil moisture monitoring results at the radioactive waste management complex of the Idaho National Engineering Laboratory, FY-1993

    Energy Technology Data Exchange (ETDEWEB)

    McElroy, D.L.

    1993-11-01

    In FY-1993, two tasks were performed for the Radioactive Waste Management Complex (RWMC) Low Level Waste Performance Assessment to estimate net infiltration from rain and snow at the Subsurface Disposal Area (SDA) and provide soil moisture data for hydrologic model calibration. The first task was to calibrate the neutron probe to convert neutron count data to soil moisture contents. A calibration equation was developed and applied to four years of neutron probe monitoring data (November 1986 to November 1990) at W02 and W06 to provide soil moisture estimates for that period. The second task was to monitor the soils at two neutron probe access tubes (W02 and W06) located in the SDA of the RWMC with a neutron probe to estimate soil moisture contents. FY-1993 monitoring indicated net infiltration varied widely across the SDA. Less than 1.2 in. of water drained into the underlying basalts near W02 in 1993. In contrast, an estimated 10.9 in. of water moved through the surficial sediments and into the underlying basalts at neutron probe access tube W06. Net infiltration estimates from the November 1986 to November 1990 neutron probe monitoring data are critical to predictive contaminant transport modeling and should be calculated and compared to the FY-1993 net infiltration estimates. In addition, plans are underway to expand the current neutron probe monitoring system in the SDA to address the variability in net infiltration across the SDA.

  4. Enhanced Plasmonic Light Absorption for Silicon Schottky-Barrier Photodetectors

    DEFF Research Database (Denmark)

    Hashemi, Mahdieh; Farzad, Mahmood Hosseini; Mortensen, N. Asger;

    2013-01-01

    Quantum efficiency of the silicon Schottky-barrier photodetector is limited by the weak interaction between the photons and electrons in the metal. By engineering the metal surfaces, metallic groove structures are proposed to achieve strong light absorption in the metal, where most of the energy...... is transferred into hot carriers near the Schottky barrier. The proposed broadband photodetector with a bi-grating metallic structure on the silicon substrate enables to absorb 76 % of the infrared light in the metal with a 200-nm bandwidth, while staying insensitive to the incident angle. These results pave...... a new promising way to attain high quantum efficiency silicon Schottky-barrier photodetectors....

  5. Second-order nonlinear silicon-organic hybrid waveguides.

    Science.gov (United States)

    Alloatti, L; Korn, D; Weimann, C; Koos, C; Freude, W; Leuthold, J

    2012-08-27

    We describe a concept for second-order nonlinear optical processes in silicon photonics. A silicon-organic hybrid (SOH) double slot waveguide is dispersion-engineered for mode phase-matching (MPM). The proposed waveguide enables highly efficient nonlinear processes in the mid-IR range. With a cladding nonlinearity of χ(2) = 230 pm/V and 20 dBm pump power at a CW wavelength of 1550 nm, we predict a gain of 14.7 dB/cm for a 3100 nm signal. The suggested structure enables for the first time efficient second-order nonlinear optical mixing in silicon photonics with standard technology.

  6. Detection, characterization and quantification of inorganic engineered nanomaterials: A review of techniques and methodological approaches for the analysis of complex samples

    Energy Technology Data Exchange (ETDEWEB)

    Laborda, Francisco, E-mail: flaborda@unizar.es; Bolea, Eduardo; Cepriá, Gemma; Gómez, María T.; Jiménez, María S.; Pérez-Arantegui, Josefina; Castillo, Juan R.

    2016-01-21

    The increasing demand of analytical information related to inorganic engineered nanomaterials requires the adaptation of existing techniques and methods, or the development of new ones. The challenge for the analytical sciences has been to consider the nanoparticles as a new sort of analytes, involving both chemical (composition, mass and number concentration) and physical information (e.g. size, shape, aggregation). Moreover, information about the species derived from the nanoparticles themselves and their transformations must also be supplied. Whereas techniques commonly used for nanoparticle characterization, such as light scattering techniques, show serious limitations when applied to complex samples, other well-established techniques, like electron microscopy and atomic spectrometry, can provide useful information in most cases. Furthermore, separation techniques, including flow field flow fractionation, capillary electrophoresis and hydrodynamic chromatography, are moving to the nano domain, mostly hyphenated to inductively coupled plasma mass spectrometry as element specific detector. Emerging techniques based on the detection of single nanoparticles by using ICP-MS, but also coulometry, are in their way to gain a position. Chemical sensors selective to nanoparticles are in their early stages, but they are very promising considering their portability and simplicity. Although the field is in continuous evolution, at this moment it is moving from proofs-of-concept in simple matrices to methods dealing with matrices of higher complexity and relevant analyte concentrations. To achieve this goal, sample preparation methods are essential to manage such complex situations. Apart from size fractionation methods, matrix digestion, extraction and concentration methods capable of preserving the nature of the nanoparticles are being developed. This review presents and discusses the state-of-the-art analytical techniques and sample preparation methods suitable for

  7. Silicon nanowire properties from theory and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Scheel, H.M.

    2007-09-10

    investigations. The surprisingly strong dependence of the Raman spectrum, involving the TO/LO peak at 520 cm{sup -1}, on laser excitation power shows a complex relation to the thermal properties of the entire experimental setup. The thermal contact to a possible heat sink (like the sample substrate or surrounding media) in the investigated SiO{sub 2} embedded silicon nanowires shows to play a pronounced role. Yielding an assignment of the gas surrounding the silicon nanowire sample by its thermal conductivity demonstrating the potential of silicon nanowires as gas sensor material. (orig.)

  8. Software engineering

    CERN Document Server

    Thorin, Marc

    1985-01-01

    Software Engineering describes the conceptual bases as well as the main methods and rules on computer programming. This book presents software engineering as a coherent and logically built synthesis and makes it possible to properly carry out an application of small or medium difficulty that can later be developed and adapted to more complex cases. This text is comprised of six chapters and begins by introducing the reader to the fundamental notions of entities, actions, and programming. The next two chapters elaborate on the concepts of information and consistency domains and show that a proc

  9. Using Collaborative Engineering to Inform Collaboration Engineering

    Science.gov (United States)

    Cooper, Lynne P.

    2012-01-01

    Collaboration is a critical competency for modern organizations as they struggle to compete in an increasingly complex, global environment. A large body of research on collaboration in the workplace focuses both on teams, investigating how groups use teamwork to perform their task work, and on the use of information systems to support team processes ("collaboration engineering"). This research essay presents collaboration from an engineering perspective ("collaborative engineering"). It uses examples from professional and student engineering teams to illustrate key differences in collaborative versus collaboration engineering and investigates how challenges in the former can inform opportunities for the latter.

  10. Using Collaborative Engineering to Inform Collaboration Engineering

    Science.gov (United States)

    Cooper, Lynne P.

    2012-01-01

    Collaboration is a critical competency for modern organizations as they struggle to compete in an increasingly complex, global environment. A large body of research on collaboration in the workplace focuses both on teams, investigating how groups use teamwork to perform their task work, and on the use of information systems to support team processes ("collaboration engineering"). This research essay presents collaboration from an engineering perspective ("collaborative engineering"). It uses examples from professional and student engineering teams to illustrate key differences in collaborative versus collaboration engineering and investigates how challenges in the former can inform opportunities for the latter.

  11. Genome scale engineering techniques for metabolic engineering.

    Science.gov (United States)

    Liu, Rongming; Bassalo, Marcelo C; Zeitoun, Ramsey I; Gill, Ryan T

    2015-11-01

    Metabolic engineering has expanded from a focus on designs requiring a small number of genetic modifications to increasingly complex designs driven by advances in genome-scale engineering technologies. Metabolic engineering has been generally defined by the use of iterative cycles of rational genome modifications, strain analysis and characterization, and a synthesis step that fuels additional hypothesis generation. This cycle mirrors the Design-Build-Test-Learn cycle followed throughout various engineering fields that has recently become a defining aspect of synthetic biology. This review will attempt to summarize recent genome-scale design, build, test, and learn technologies and relate their use to a range of metabolic engineering applications.

  12. Virtual Solar Energy Center: A Case Study of the Use of Advanced Visualization Techniques for the Comprehension of Complex Engineering Products and Processes

    Science.gov (United States)

    Ritter, Kenneth August, III

    Industry has a continuing need to train its workforce on recent engineering developments, but many engineering products and processes are hard to explain because of limitations of size, visibility, time scale, cost, and safety. The product or process might be difficult to see because it is either very large or very small, because it is enclosed within an opaque container, or because it happens very fast or very slowly. Some engineering products and processes are also costly or unsafe to use for training purposes, and sometimes the domain expert is not physically available at the training location. All these limitations can potentially be addressed using advanced visualization techniques such as virtual reality. This dissertation describes the development of an immersive virtual reality application using the Six Sigma DMADV process to explain the main equipment and processes used in a concentrating solar power plant. The virtual solar energy center (VEC) application was initially developed and tested in a Cave Automatic Virtual Environment (CAVE) during 2013 and 2014. The software programs used for development were SolidWorks, 3ds Max Design, and Unity 3D. Current hardware and software technologies that could complement this research were analyzed. The NVIDA GRID Visual Computing Appliance (VCA) was chosen as the rendering solution for animating complex CAD models in this application. The MiddleVR software toolkit was selected as the toolkit for VR interactions and CAVE display. A non-immersive 3D version of the VEC application was tested and shown to be an effective training tool in late 2015. An immersive networked version of the VEC allows the user to receive live instruction from a trainer being projected via depth camera imagery from a remote location. Four comparative analysis studies were performed. These studies used the average normalized gain from pre-test scores to determine the effectiveness of the various training methods. With the DMADV approach

  13. Nonlinear silicon photonics

    Science.gov (United States)

    Borghi, M.; Castellan, C.; Signorini, S.; Trenti, A.; Pavesi, L.

    2017-09-01

    Silicon photonics is a technology based on fabricating integrated optical circuits by using the same paradigms as the dominant electronics industry. After twenty years of fervid development, silicon photonics is entering the market with low cost, high performance and mass-manufacturable optical devices. Until now, most silicon photonic devices have been based on linear optical effects, despite the many phenomenologies associated with nonlinear optics in both bulk materials and integrated waveguides. Silicon and silicon-based materials have strong optical nonlinearities which are enhanced in integrated devices by the small cross-section of the high-index contrast silicon waveguides or photonic crystals. Here the photons are made to strongly interact with the medium where they propagate. This is the central argument of nonlinear silicon photonics. It is the aim of this review to describe the state-of-the-art in the field. Starting from the basic nonlinearities in a silicon waveguide or in optical resonator geometries, many phenomena and applications are described—including frequency generation, frequency conversion, frequency-comb generation, supercontinuum generation, soliton formation, temporal imaging and time lensing, Raman lasing, and comb spectroscopy. Emerging quantum photonics applications, such as entangled photon sources, heralded single-photon sources and integrated quantum photonic circuits are also addressed at the end of this review.

  14. Nonlinear silicon photonics

    Science.gov (United States)

    Tsia, Kevin K.; Jalali, Bahram

    2010-05-01

    An intriguing optical property of silicon is that it exhibits a large third-order optical nonlinearity, with orders-ofmagnitude larger than that of silica glass in the telecommunication band. This allows efficient nonlinear optical interaction at relatively low power levels in a small footprint. Indeed, we have witnessed a stunning progress in harnessing the Raman and Kerr effects in silicon as the mechanisms for enabling chip-scale optical amplification, lasing, and wavelength conversion - functions that until recently were perceived to be beyond the reach of silicon. With all the continuous efforts developing novel techniques, nonlinear silicon photonics is expected to be able to reach even beyond the prior achievements. Instead of providing a comprehensive overview of this field, this manuscript highlights a number of new branches of nonlinear silicon photonics, which have not been fully recognized in the past. In particular, they are two-photon photovoltaic effect, mid-wave infrared (MWIR) silicon photonics, broadband Raman effects, inverse Raman scattering, and periodically-poled silicon (PePSi). These novel effects and techniques could create a new paradigm for silicon photonics and extend its utility beyond the traditionally anticipated applications.

  15. Periodically poled silicon

    Science.gov (United States)

    Hon, Nick K.; Tsia, Kevin K.; Solli, Daniel R.; Khurgin, Jacob B.; Jalali, Bahram

    2010-02-01

    Bulk centrosymmetric silicon lacks second-order optical nonlinearity χ(2) - a foundational component of nonlinear optics. Here, we propose a new class of photonic device which enables χ(2) as well as quasi-phase matching based on periodic stress fields in silicon - periodically-poled silicon (PePSi). This concept adds the periodic poling capability to silicon photonics, and allows the excellent crystal quality and advanced manufacturing capabilities of silicon to be harnessed for devices based on χ(2)) effects. The concept can also be simply achieved by having periodic arrangement of stressed thin films along a silicon waveguide. As an example of the utility, we present simulations showing that mid-wave infrared radiation can be efficiently generated through difference frequency generation from near-infrared with a conversion efficiency of 50% based on χ(2) values measurements for strained silicon reported in the literature [Jacobson et al. Nature 441, 199 (2006)]. The use of PePSi for frequency conversion can also be extended to terahertz generation. With integrated piezoelectric material, dynamically control of χ(2)nonlinearity in PePSi waveguide may also be achieved. The successful realization of PePSi based devices depends on the strength of the stress induced χ(2) in silicon. Presently, there exists a significant discrepancy in the literature between the theoretical and experimentally measured values. We present a simple theoretical model that produces result consistent with prior theoretical works and use this model to identify possible reasons for this discrepancy.

  16. ALICE silicon strip module

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    This small silicon detector strip will be inserted into the inner tracking system (ITS) on the ALICE detector at CERN. This detector relies on state-of-the-art particle tracking techniques. These double-sided silicon strip modules have been designed to be as lightweight and delicate as possible as the ITS will eventually contain five square metres of these devices.

  17. SILICON CARBIDE DATA SHEETS

    Science.gov (United States)

    These data sheets present a compilation of a wide range of electrical, optical and energy values for alpha and beta- silicon carbide in bulk and film...spectrum. Energy data include energy bands, energy gap and energy levels for variously-doped silicon carbide , as well as effective mass tables, work

  18. Photoluminescence of Silicon Nanocrystals in Silicon Oxide

    Directory of Open Access Journals (Sweden)

    L. Ferraioli

    2007-01-01

    Full Text Available Recent results on the photoluminescence properties of silicon nanocrystals embedded in silicon oxide are reviewed and discussed. The attention is focused on Si nanocrystals produced by high-temperature annealing of silicon rich oxide layers deposited by plasma-enhanced chemical vapor deposition. The influence of deposition parameters and layer thickness is analyzed in detail. The nanocrystal size can be roughly controlled by means of Si content and annealing temperature and time. Unfortunately, a technique for independently fine tuning the emission efficiency and the size is still lacking; thus, only middle size nanocrystals have high emission efficiency. Interestingly, the layer thickness affects the nucleation and growth kinetics so changing the luminescence efficiency.

  19. EDITORIAL: Special issue on silicon photonics

    Science.gov (United States)

    Reed, Graham; Paniccia, Mario; Wada, Kazumi; Mashanovich, Goran

    2008-06-01

    The technology now known as silicon photonics can be traced back to the pioneering work of Soref in the mid-1980s (see, for example, Soref R A and Lorenzo J P 1985 Electron. Lett. 21 953). However, the nature of the research conducted today, whilst it builds upon that early work, is unrecognizable in terms of technology metrics such as device efficiency, device data rate and device dimensions, and even in targeted applications areas. Today silicon photonics is still evolving, and is enjoying a period of unprecedented attention in terms of research focus. This has resulted in orders-of-magnitude improvement in device performance over the last few years to levels many thought were impossible. However, despite the existence of the research field for more than two decades, silicon is still regarded as a 'new' optical material, one that is being manipulated and modified to satisfy the requirements of a range of applications. This is somewhat ironic since silicon is one of the best known and most thoroughly studied materials, thanks to the electronics industry that has made silicon its material of choice. The principal reasons for the lack of study of this 'late developer' are that (i) silicon is an indirect bandgap material and (ii) it does not exhibit a linear electro-optic (Pockels) effect. The former condition means that it is difficult to make a laser in silicon based on the intrinsic performance of the material, and consequently, in recent years, researchers have attempted to modify the material to artificially engineer the conditions for lasing to be viable (see, for example, the review text, Jalali B et al 2008 Silicon Lasers in Silicon Photonics: The State of the Art ed G T Reed (New York: Wiley)). The latter condition means that optical modulators are intrinsically less efficient in silicon than in some other materials, particularly when targeting the popular telecommunications wavelengths around 1.55 μm. Therefore researchers have sought alternative

  20. Steps towards silicon optoelectronics

    CERN Document Server

    Starovoytov, A

    1999-01-01

    nanostructure fabrication. Thus, this thesis makes a dual contribution to the chosen field: it summarises the present knowledge on the possibility of utilising optical properties of nanocrystalline silicon in silicon-based electronics, and it reports new results within the framework of the subject. The main conclusion is that due to its promising optoelectronic properties nanocrystalline silicon remains a prospective competitor for the cheapest and fastest microelectronics of the next century. This thesis addresses the issue of a potential future microelectronics technology, namely the possibility of utilising the optical properties of nanocrystalline silicon for optoelectronic circuits. The subject is subdivided into three chapters. Chapter 1 is an introduction. It formulates the oncoming problem for microelectronic development, explains the basics of Integrated Optoelectronics, introduces porous silicon as a new light-emitting material and gives a brief review of other competing light-emitting material syst...

  1. Integrated Nanophotonic Silicon Devices for Next Generation Computing Chips

    Science.gov (United States)

    Djordjevic, Stevan

    Development of the computing platform of the future depends largely on high bandwidth interconnects at intra-die level. Silicon photonics, as an innately CMOS compatible technology, is a promising candidate for delivering terabit per second bandwidths through the use of wavelength division multiplex (WDM) signaling. Silicon photonic interconnects offer unmatched bandwidth, density, energy efficiency, latency and reach, compared with the electrical interconnects. WDM silicon photonic links are viewed today as a promising solution for resolving the inter/intra-chip communication bottlenecks for high performance computing systems. Towards its maturity, silicon photonic technology has to resolve the issues of waveguide propagation loss, density of device integration, thermal stability of resonant devices, heterogeneous integration of various materials and many other problems. This dissertation describes the development of integrated photonic technology on silicon and silicon nitride platforms in the increased order of device complexity, from the fabrication process of low loss waveguides and efficient off-chip coupling devices, to the die-size reconfigurable lattice filters for optical signal processing. Particular emphasis of the dissertation is on the demonstration of CMOS-compatible, athermal silicon ring modulators that potentially hold the key to solving the thermal problem of silicon photonic devices. The development of high quality amorphous titanium dioxide films with negative thermo-optic coefficient enabled the fabrication of gigahertz-bandwidth silicon ring modulators that can be made insensitive to ambient temperature changes.

  2. Silicon control of bacterial and viral diseases in plants

    Directory of Open Access Journals (Sweden)

    Sakr Nachaat

    2016-12-01

    Full Text Available Silicon plays an important role in providing tolerance to various abiotic stresses and augmenting plant resistance against diseases. However, there is a paucity of reports about the effect of silicon on bacterial and viral pathogens of plants. In general, the effect of silicon on plant resistance against bacterial diseases is considered to be due to either physical defense or increased biochemical defense. In this study, the interaction between silicon foliar or soil-treatments and reduced bacterial and viral severity was reviewed. The current review explains the agricultural importance of silicon in plants, refers to the control of bacterial pathogens in different crop plants by silicon application, and underlines the different mechanisms of silicon-enhanced resistance. A section about the effect of silicon in decreasing viral disease intensity was highlighted. By combining the data presented in this study, a better comprehension of the complex interaction between silicon foliar- or soil-applications and bacterial and viral plant diseases could be achieved.

  3. Applying the foundations of enterprise systems engineering in complex real-world environments: lessons learnt from real-world project examples

    CSIR Research Space (South Africa)

    Kotzé, Paula

    2016-11-01

    Full Text Available Enterprise systems engineering (ESE) is a multidisciplinary approach that combines traditional systems engineering (TSE) and strategic management to address methods and approaches for aligning system architectures, system development and system...

  4. Extreme-Environment Silicon-Carbide (SiC) Wireless Sensor Suite

    Science.gov (United States)

    Yang, Jie

    2015-01-01

    Phase II objectives: Develop an integrated silicon-carbide wireless sensor suite capable of in situ measurements of critical characteristics of NTP engine; Compose silicon-carbide wireless sensor suite of: Extreme-environment sensors center, Dedicated high-temperature (450 deg C) silicon-carbide electronics that provide power and signal conditioning capabilities as well as radio frequency modulation and wireless data transmission capabilities center, An onboard energy harvesting system as a power source.

  5. Silicon germanium mask for deep silicon etching

    KAUST Repository

    Serry, Mohamed

    2014-07-29

    Polycrystalline silicon germanium (SiGe) can offer excellent etch selectivity to silicon during cryogenic deep reactive ion etching in an SF.sub.6/O.sub.2 plasma. Etch selectivity of over 800:1 (Si:SiGe) may be achieved at etch temperatures from -80 degrees Celsius to -140 degrees Celsius. High aspect ratio structures with high resolution may be patterned into Si substrates using SiGe as a hard mask layer for construction of microelectromechanical systems (MEMS) devices and semiconductor devices.

  6. Reduced Moment-Based Models for Oxygen Precipitates and Dislocation Loops in Silicon

    Science.gov (United States)

    Trzynadlowski, Bart

    The demand for ever smaller, higher-performance integrated circuits and more efficient, cost-effective solar cells continues to push the frontiers of process technology. Fabrication of silicon devices requires extremely precise control of impurities and crystallographic defects. Failure to do so not only reduces performance, efficiency, and yield, it threatens the very survival of commercial enterprises in today's fiercely competitive and price-sensitive global market. The presence of oxygen in silicon is an unavoidable consequence of the Czochralski process, which remains the most popular method for large-scale production of single-crystal silicon. Oxygen precipitates that form during thermal processing cause distortion of the surrounding silicon lattice and can lead to the formation of dislocation loops. Localized deformation caused by both of these defects introduces potential wells that trap diffusing impurities such as metal atoms, which is highly desirable if done far away from sensitive device regions. Unfortunately, dislocations also reduce the mechanical strength of silicon, which can cause wafer warpage and breakage. Engineers must negotiate this and other complex tradeoffs when designing fabrication processes. Accomplishing this in a complex, modern process involving a large number of thermal steps is impossible without the aid of computational models. In this dissertation, new models for oxygen precipitation and dislocation loop evolution are described. An oxygen model using kinetic rate equations to evolve the complete precipitate size distribution was developed first. This was then used to create a reduced model tracking only the moments of the size distribution. The moment-based model was found to run significantly faster than its full counterpart while accurately capturing the evolution of oxygen precipitates. The reduced model was fitted to experimental data and a sensitivity analysis was performed to assess the robustness of the results. Source

  7. Engineering surveying

    CERN Document Server

    Schofield, W

    2007-01-01

    Engineering surveying involves determining the position of natural and man-made features on or beneath the Earth's surface and utilizing these features in the planning, design and construction of works. It is a critical part of any engineering project. Without an accurate understanding of the size, shape and nature of the site the project risks expensive and time-consuming errors or even catastrophic failure.Engineering Surveying 6th edition covers all the basic principles and practice of this complex subject and the authors bring expertise and clarity. Previous editions of this classic text have given readers a clear understanding of fundamentals such as vertical control, distance, angles and position right through to the most modern technologies, and this fully updated edition continues that tradition.This sixth edition includes:* An introduction to geodesy to facilitate greater understanding of satellite systems* A fully updated chapter on GPS, GLONASS and GALILEO for satellite positioning in surveying* Al...

  8. Stable 600 °C silicon carbide MEMS pressure transducers

    Science.gov (United States)

    Okojie, Robert S.

    2007-04-01

    This paper presents a review of recent results of silicon carbide (SiC) piezoresistive pressure transducers that have been demonstrated to operate up to 600 °C. The results offer promise to extend pressure measurement to higher temperatures beyond the capability of conventional semiconductor pressure transducers. The development also provides three immediate significant technological benefits: i) wider frequency bandwidth (overcomes acoustic attenuation associated with pitot tubes), ii) accuracy (improved stable output at high temperature), and iii) reduced packaging complexity (no package cooling required). Operation at 600 °C provides immediate applications in military and commercial jet engines in which critical static and dynamic pressure measurements are performed to improve engine performance (i.e., reduced emission and combustor instabilities) and improved CFD code validation. The pressure sensor is packaged by a novel MEMS direct chip attach (MEMS-DCA) technique that eliminates the need for wire bonding, thereby removing some reliability issues encountered at high temperature. Generally, at 600 °C the full-scale output (FSO) of these transducers drops by about 50-65 % of the room temperature values, which can be compensated for with external signal conditioning circuitry.

  9. In situ technology evaluation and functional and operational guidelines for treatability studies at the radioactive waste management complex at the Idaho National Engineering Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Hyde, R.A.; Donehey, A.J.; Piper, R.B.; Roy, M.W.; Rubert, A.L.; Walker, S.

    1991-07-01

    The purpose of this document is to provide EG G Idaho's Waste Technology Development Department with a basis for selection of in situ technologies for demonstration at the Radioactive Waste Management Complex (RWMC) of the Idaho National Engineering Laboratory (INEL) and to provide information for Feasibility Studies to be performed according to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). The demonstrations will aid in meeting Environmental Restoration/Waste Management (ER/WM) schedules for remediation of waste at Waste Area Group (WAG) 7. This report is organized in six sections. Section 1, summarizes background information on the sites to be remediated at WAG-7, specifically, the acid pit, soil vaults, and low-level pits and trenches. Section 2 discusses the identification and screening of in situ buried waste remediation technologies for these sites. Section 3 outlines the design requirements. Section 4 discusses the schedule (in accordance with Buried Waste Integrated Demonstration (BWID) scoping). Section 5 includes recommendations for the acid pit, soil vaults, and low-level pits and trenches. A listing of references used to compile the report is given in Section 6. Detailed technology information is included in the Appendix section of this report.

  10. Structural and biophysical characterization of an epitope-specific engineered Fab fragment and complexation with membrane proteins: implications for co-crystallization.

    Science.gov (United States)

    Johnson, Jennifer L; Entzminger, Kevin C; Hyun, Jeongmin; Kalyoncu, Sibel; Heaner, David P; Morales, Ivan A; Sheppard, Aly; Gumbart, James C; Maynard, Jennifer A; Lieberman, Raquel L

    2015-04-01

    Crystallization chaperones are attracting increasing interest as a route to crystal growth and structure elucidation of difficult targets such as membrane proteins. While strategies to date have typically employed protein-specific chaperones, a peptide-specific chaperone to crystallize multiple cognate peptide epitope-containing client proteins is envisioned. This would eliminate the target-specific chaperone-production step and streamline the co-crystallization process. Previously, protein engineering and directed evolution were used to generate a single-chain variable (scFv) antibody fragment with affinity for the peptide sequence EYMPME (scFv/EE). This report details the conversion of scFv/EE to an anti-EE Fab format (Fab/EE) followed by its biophysical characterization. The addition of constant chains increased the overall stability and had a negligible impact on the antigen affinity. The 2.0 Å resolution crystal structure of Fab/EE reveals contacts with larger surface areas than those of scFv/EE. Surface plasmon resonance, an enzyme-linked immunosorbent assay, and size-exclusion chromatography were used to assess Fab/EE binding to EE-tagged soluble and membrane test proteins: namely, the β-barrel outer membrane protein intimin and α-helical A2a G protein-coupled receptor (A2aR). Molecular-dynamics simulation of the intimin constructs with and without Fab/EE provides insight into the energetic complexities of the co-crystallization approach.

  11. A special purpose silicon compiler for designing supercomputing VLSI systems

    Science.gov (United States)

    Venkateswaran, N.; Murugavel, P.; Kamakoti, V.; Shankarraman, M. J.; Rangarajan, S.; Mallikarjun, M.; Karthikeyan, B.; Prabhakar, T. S.; Satish, V.; Venkatasubramaniam, P. R.

    1991-01-01

    Design of general/special purpose supercomputing VLSI systems for numeric algorithm execution involves tackling two important aspects, namely their computational and communication complexities. Development of software tools for designing such systems itself becomes complex. Hence a novel design methodology has to be developed. For designing such complex systems a special purpose silicon compiler is needed in which: the computational and communicational structures of different numeric algorithms should be taken into account to simplify the silicon compiler design, the approach is macrocell based, and the software tools at different levels (algorithm down to the VLSI circuit layout) should get integrated. In this paper a special purpose silicon (SPS) compiler based on PACUBE macrocell VLSI arrays for designing supercomputing VLSI systems is presented. It is shown that turn-around time and silicon real estate get reduced over the silicon compilers based on PLA's, SLA's, and gate arrays. The first two silicon compiler characteristics mentioned above enable the SPS compiler to perform systolic mapping (at the macrocell level) of algorithms whose computational structures are of GIPOP (generalized inner product outer product) form. Direct systolic mapping on PLA's, SLA's, and gate arrays is very difficult as they are micro-cell based. A novel GIPOP processor is under development using this special purpose silicon compiler.

  12. Slip Casting and Green Body Evaluation of 6% Yttria, 2% Alumina Silicon Nitride

    Science.gov (United States)

    1991-12-01

    Some Properrie of Aqucouw Silicon Nitride SuN- pensons. Ponrahkovaya Metallurgrya. no. 3 (159), March 1976, p. 37. 7. GREIL. P., NAGEL. A., STADELMANN ...H., and PETZOW, G. Revie%, Colloidal Proce=ing of Silicon Nitride Ceramics. Ceramic Materi- als and Componenls for Engines, p. 319. 8. STADELMANN II

  13. The –SH Protection Method for Determining Accurate Kd Values for Enzyme-Coenzyme Complexes of NAD+-Dependent Glutamate Dehydrogenase and Engineered Mutants: Evidence for Nonproductive NADPH Complexes

    Directory of Open Access Journals (Sweden)

    Joanna Griffin

    2010-01-01

    Full Text Available Inactivation rates have been measured for clostridial glutamate dehydrogenase and several engineered mutants at various DTNB concentrations. Analysis of rate constants allowed determination of Kd for each non-covalent enzyme-DTNB complex and the rate constant for reaction to form the inactive enzyme-thionitrobenzoate adduct. Both parameters are sensitive to the mutations F238S, P262S, the double mutation F238S/P262S, and D263K, all in the coenzyme binding site. Study of the effects of NAD+, NADH and NADPH at various concentrations in protecting against inactivation by 200 μM DTNB allowed determination of Kd values for binding of these coenzymes to each protein, yielding surprising results. The mutations were originally devised to lessen discrimination against the disfavoured coenzyme NADP(H, and activity measurements showed this was achieved. However, the Kd determinations indicated that, although Kd values for NAD+ and NADH were increased considerably, Kd for NADPH was increased even more than for NADH, so that discrimination against binding of NADPH was not decreased. This apparent contradiction can only be explained if NADPH has a nonproductive binding mode that is not weakened by the mutations, and a catalytically productive mode that, though strengthened, is masked by the nonproductive binding. Awareness of the latter is important in planning further mutagenesis.

  14. Engineering Ontologies

    OpenAIRE

    Borst, Pim; Akkermans, Hans; Top, Jan

    1997-01-01

    We analyse the construction as well as the role of ontologies in knowledge sharing and reuse for complex industrial applications. In this article, the practical use of ontologies in large-scale applications not restricted to knowledge-based systems is demonstrated, for the domain of engineering systems modelling, simulation and design. A general and formal ontology, called PHYSSYS, for dynamic physical systems is presented and its structuring principles are discussed. We show how the PHYSSYS ...

  15. Integrated cooling devices in silicon technology

    Science.gov (United States)

    Perret, C.; Avenas, Y.; Gillot, Ch.; Boussey, J.; Schaeffer, Ch.

    2002-05-01

    Silicon technology has become a good alternative to copper for the elaboration of efficient cooling devices required in power electronics domain. Owing to its high degree of miniaturization, it is expected to provide suitable microchannels and other inlets holes that were not achievable by copper micromachining. Besides, the use of silicon technology provides a variety of bare materials (silicon dioxide, silicon nitride, silicide, etc.) which may be either insulator or conductive, with a good or bad thermal conductivity. This large choice makes it possible to built up rather complex multilayer devices with mechanical properties good enough in comparison with hybrid copper technology heat sinks. Nevertheless, the use of silicon technology, where the microchannel width may reach few tens of microns, raises fundamental features concerning the fluid displacement within such small sections. More precisely, fundamental fluid mechanics studies have to be conducted out in order to get an accurate description of the fluid boundary layers and to provide basic data on the exchange mechanisms occurring at these surfaces. In this paper, we review the operation principles of both single- and double-phase heat exchange devices elaborated in silicon technology. Forced-convection heat sinks as well as integrated micro heat pipes are analyzed. An analytical approach is adopted to evaluate their total thermal resistances as a function of several geometrical parameters. Numerical simulations are then used in order to assess the accuracy of the analytical approach and to evaluate the impact of the fluidic aspects on the whole performance. The optimum devices are then conceived thanks to an appropriate optimization procedure taken into account the several experimental constraints. Reference values of similar copper devices are reminded and the advantages of the silicon integrated approach are highlighted.

  16. Transformational silicon electronics

    KAUST Repository

    Rojas, Jhonathan Prieto

    2014-02-25

    In today\\'s traditional electronics such as in computers or in mobile phones, billions of high-performance, ultra-low-power devices are neatly integrated in extremely compact areas on rigid and brittle but low-cost bulk monocrystalline silicon (100) wafers. Ninety percent of global electronics are made up of silicon. Therefore, we have developed a generic low-cost regenerative batch fabrication process to transform such wafers full of devices into thin (5 μm), mechanically flexible, optically semitransparent silicon fabric with devices, then recycling the remaining wafer to generate multiple silicon fabric with chips and devices, ensuring low-cost and optimal utilization of the whole substrate. We show monocrystalline, amorphous, and polycrystalline silicon and silicon dioxide fabric, all from low-cost bulk silicon (100) wafers with the semiconductor industry\\'s most advanced high-κ/metal gate stack based high-performance, ultra-low-power capacitors, field effect transistors, energy harvesters, and storage to emphasize the effectiveness and versatility of this process to transform traditional electronics into flexible and semitransparent ones for multipurpose applications. © 2014 American Chemical Society.

  17. Roadmap on silicon photonics

    Science.gov (United States)

    Thomson, David; Zilkie, Aaron; Bowers, John E.; Komljenovic, Tin; Reed, Graham T.; Vivien, Laurent; Marris-Morini, Delphine; Cassan, Eric; Virot, Léopold; Fédéli, Jean-Marc; Hartmann, Jean-Michel; Schmid, Jens H.; Xu, Dan-Xia; Boeuf, Frédéric; O'Brien, Peter; Mashanovich, Goran Z.; Nedeljkovic, M.

    2016-07-01

    Silicon photonics research can be dated back to the 1980s. However, the previous decade has witnessed an explosive growth in the field. Silicon photonics is a disruptive technology that is poised to revolutionize a number of application areas, for example, data centers, high-performance computing and sensing. The key driving force behind silicon photonics is the ability to use CMOS-like fabrication resulting in high-volume production at low cost. This is a key enabling factor for bringing photonics to a range of technology areas where the costs of implementation using traditional photonic elements such as those used for the telecommunications industry would be prohibitive. Silicon does however have a number of shortcomings as a photonic material. In its basic form it is not an ideal material in which to produce light sources, optical modulators or photodetectors for example. A wealth of research effort from both academia and industry in recent years has fueled the demonstration of multiple solutions to these and other problems, and as time progresses new approaches are increasingly being conceived. It is clear that silicon photonics has a bright future. However, with a growing number of approaches available, what will the silicon photonic integrated circuit of the future look like? This roadmap on silicon photonics delves into the different technology and application areas of the field giving an insight into the state-of-the-art as well as current and future challenges faced by researchers worldwide. Contributions authored by experts from both industry and academia provide an overview and outlook for the silicon waveguide platform, optical sources, optical modulators, photodetectors, integration approaches, packaging, applications of silicon photonics and approaches required to satisfy applications at mid-infrared wavelengths. Advances in science and technology required to meet challenges faced by the field in each of these areas are also addressed together with

  18. Recrystallization of polycrystalline silicon

    Science.gov (United States)

    Lall, C.; Kulkarni, S. B.; Graham, C. D., Jr.; Pope, D. P.

    1981-01-01

    Optical metallography is used to investigate the recrystallization properties of polycrystalline semiconductor-grade silicon. It is found that polycrystalline silicon recrystallizes at 1380 C in relatively short times, provided that the prior deformation is greater than 30%. For a prior deformation of about 40%, the recrystallization process is essentially complete in about 30 minutes. Silicon recrystallizes at a substantially slower rate than metals at equivalent homologous temperatures. The recrystallized grain size is insensitive to the amount of prestrain for strains in the range of 10-50%.

  19. Porous silicon gettering

    Energy Technology Data Exchange (ETDEWEB)

    Tsuo, Y.S.; Menna, P.; Pitts, J.R. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1996-05-01

    The authors have studied a novel extrinsic gettering method that uses the large surface areas produced by a porous-silicon etch as gettering sites. The annealing step of the gettering used a high-flux solar furnace. They found that a high density of photons during annealing enhanced the impurity diffusion to the gettering sites. The authors used metallurgical-grade Si (MG-Si) prepared by directional solidification casing as the starting material. They propose to use porous-silicon-gettered MG-Si as a low-cost epitaxial substrate for polycrystalline silicon thin-film growth.

  20. Microstructured silicon radiation detector

    Energy Technology Data Exchange (ETDEWEB)

    Okandan, Murat; Derzon, Mark S.; Draper, Bruce L.

    2017-03-14

    A radiation detector comprises a silicon body in which are defined vertical pores filled with a converter material and situated within silicon depletion regions. One or more charge-collection electrodes are arranged to collect current generated when secondary particles enter the silicon body through walls of the pores. The pores are disposed in low-density clusters, have a majority pore thickness of 5 .mu.m or less, and have a majority aspect ratio, defined as the ratio of pore depth to pore thickness, of at least 10.