Interconnect Configurations Research Articles

Molecular dynamics study of the positioned single-walled carbon nanotubes with T-, X-, Y- junction during nanoscale soldering

The miniaturization of electronics devices into the nanometer scale is indispensable for next-generation semi-conductor technology. However, the determination of interconnect structures of carbon nanotubes (CNTs) is difficult to do experimentally in nanosoldering process and the investigation of dynamic evolution between CNTs is still lacking during nanoscale soldering. So, the nanoscale soldering of positioned single-walled carbon nanotubes with “T-”, “Y-”and “X-” junction is proposed and demonstrated with molecular dynamics simulation. As the simulation results, when the number of the deposited nanoparticles is small, the nanoscale soldering processes of “T-” and “Y-” junction are accomplished through the silver nanoparticles melting and bunching up in a larger droplet due to its higher surface energy. With the increase of simulation time, the splitting phenomenon of nano-droplet exists in the interconnection configuration. However, when the number of the deposited nanoparticles is large, the nano-mound can completely wrap the crossed X-junction without splitting phenomenon. Furthermore, the dominant mechanism of the interesting phenomenon is also analyzed.

Single‐configuration fault detection in application‐dependent testing of field programmable gate array interconnects

This study presents a new method for application testing of field programmable gate array (FPGA) interconnects at run time. This method utilises new features related to the function for the programming of the look up tables (LUTs), the utilisation (by logic activation/deactivation) of the nets in a interconnect configuration as well as the primary (unused) input/outputs (IOs) of the FPGAs. A new LUT programming function is introduced; the proposed method retains the original interconnect configuration and modifies the function of the LUTs using the so-called 1-bit sum function (1-BSF); the 1-BSF detects all possible stuck-at and bridging faults (of all cardinalities) by utilising the all zeros' vector and a walking-1 test set. As validated by simulation for benchmark circuits (implemented on the Xilinx Virtex4 and Virtex5), the proposed method (with a polynomial time complexity) results in a single test configuration with 100% coverage. These results also show that the proposed method requires a larger number of test vectors and an availability of unused IOs.

Development of a New Insulation Approach for the LHC Main 13 kA Interconnection Splices

In the long LHC (Large Hadron Collider) shutdown in 2013 it is foreseen to intervene on all the 13 kA interconnections in order to guarantee the necessary margin and redundancy to provide safe LHC operation at 7 TeV per beam. This implies reinforcement of the present interconnection configuration including a new insulation scheme of the busbars. The purpose of the new insulation model is to provide dielectric insulation with at least the same performance as its predecessor currently installed in the LHC machine, but in addition to contain the Lorentz forces. This paper describes the analytic and empirical approach of development to reach a new insulation concept based on state of the art materials and manufacturing techniques.

Governance at the Internet's Core: The Geopolitics of Interconnection and Internet Exchange Points (IXPs) in Emerging Markets

The market arrangements negotiated between Internet operators to interconnect at private or shared exchange points are a critical form of privatized global governance necessary for the Internet to remain operational, secure, and technically optimized. Questions about introducing regulatory oversight of this interconnection have always been present, whether to incentivize interconnection or mediate equitable payment structures for the exchange of traffic between network operators. Recently, the European Telecommunications Network Operators’ Association submitted a proposal in advance of the ITU’s World Conference on International Telecommunications calling for nation state involvement in ‘facilitating’ interconnection and the prospect of compensation between providers based on ‘sending party network pays.’ This later suggestion would amount to a content tax whereby companies such as Apple, Google, Netflix, and the BBC would pay a network operator when its customers choose to download content from these sites. Rather than content being universally accessible, content providers would have to decide whether to allow access to their content in parts of the world imposing this levy. Interconnection regulation would also affect Internet infrastructure and, in particular, the financial viability and growth of Internet Exchange Points (IXPs) in emerging markets. These shared interconnection sites play a critical role in emerging markets by bringing content closer to users, promoting local peering connectivity among regional operators, reducing interconnection costs, and reducing the dependency of local connectivity on foreign exchange points. Drawing from data on the global state of peering requirements for settlement-free peering, industry trends toward flattening interconnection configurations, and data on the global distribution of IXPs, this paper explains the increasing economic and technical importance of IXPs to local geographies, examines how they are emerging sites of Internet governance power in areas like critical infrastructure protection and national economic competitiveness, and explains several ways in which regulating interconnection would provide economic disincentives for the further development of IXPs in emerging markets.

Modeling of Crosstalk Effects in Multiwall Carbon Nanotube Interconnects

Crosstalk effects in multiwall carbon nanotube (MWCNT) interconnects for future ICs are investigated by virtue of the equivalent single conductor model and the finite-difference time-domain solution of transmission line equations. The worst case time delay and the peak crosstalk voltage on victim wire of multiwire MWCNT interconnect configurations are derived and compared to those of the copper (Cu) wire counterparts for the intermediate and global interconnects at the 22- and 14-nm technology nodes. The numerical results illustrate that the crosstalk-induced time delays in the MWCNT interconnects are much smaller than those in the Cu interconnects, in particular, for longer wires. Nevertheless, the MWCNT interconnects exhibit little improvement on the crosstalk-induced noises in comparison with their Cu counterparts.

Selection of Steam Drum Level Control Method for Multiple Drum Interacting Loops Pressure Tube-Type BWR

Three element Steam Drum (SD) Level Controller has been conventionally used for most of the boilers, Nuclear power plant steam generator & Boiling Water Reactor (BWRs). Based on the process dynamic studies it was found that this scheme does not work properly for an interacting, interconnected multiple loop boiling water system i.e., Advanced Heavy Water Reactor (AHWR). It is a pressure tube type light water cooled heavy water moderated Boiling Water Reactor (BWR). It has 4-inter-connected parallel loops with 113 × 4 = 452 boiling channels in the Main Heat Transport (MHT) system. These multiple (four) interconnected loops influences the Steam Drum (SD) level control adversely. Such a behavior has not been reported in the open literature. The open loop response is stable, non-oscillatory and non-diverging for a step change in the feed flow rates. Also it is not possible to maintain a steady level in all the SDs even without any external disturbance/perturbation with 4 conventional 3-element individual SD level controllers. To overcome these interactions it is proposed to interconnect all the four steam drums in the liquid & vapor regions respectively. This makes the 4 SDs behave like a single entity. The influence of the interconnect configuration & the level controller are studied in detail to find a robust solution. The response obtained for unsymmetrical core power, symmetrical power maneuvering and reactor trip transients shows that the SD levels do not diverge and quickly settle very near to the set points assigned with SD interconnect schemes.

Existence and robustness of phase-locking in coupled Kuramoto oscillators under mean-field feedback

Motivated by the recent development of Deep Brain Stimulation (DBS) for neurological diseases, we study a network of interconnected oscillators under the influence of mean-field feedback and analyze the robustness of its phase-locking with respect to general inputs. Under standard assumptions, this system can be reduced to a modified version of the Kuramoto model of coupled nonlinear oscillators. In the first part of the paper we present an analytical study on the existence of phase-locked solutions under generic interconnection and feedback configurations. In particular we show that, in general, no oscillating phase-locked solutions can co-exist with any non-zero proportional mean-field feedback. In the second part we prove some robustness properties of phase-locked solutions (namely total stability). This general result allows in particular to justify the persistence of practically phase-locked states if sufficiently small feedback gains are applied, and to give explicit necessary conditions on the intensity of a desynchronizing mean-field feedback. Furthermore, the Lyapunov function used in the analysis provides a new characterization of the robust phase-locked configurations in the Kuramoto system with symmetric interconnections.

Toward nanofluids of ultra-high thermal conductivity

The assessment of proposed origins for thermal conductivity enhancement in nanofluids signifies the importance of particle morphology and coupled transport in determining nanofluid heat conduction and thermal conductivity. The success of developing nanofluids of superior conductivity depends thus very much on our understanding and manipulation of the morphology and the coupled transport. Nanofluids with conductivity of upper Hashin-Shtrikman (H-S) bound can be obtained by manipulating particles into an interconnected configuration that disperses the base fluid and thus significantly enhancing the particle-fluid interfacial energy transport. Nanofluids with conductivity higher than the upper H-S bound could also be developed by manipulating the coupled transport among various transport processes, and thus the nature of heat conduction in nanofluids. While the direct contributions of ordered liquid layer and particle Brownian motion to the nanofluid conductivity are negligible, their indirect effects can be significant via their influence on the particle morphology and/or the coupled transport.

Steam drum process dynamics and level control of a pressure tube BWR

Abstract The Advanced Heavy Water Reactor (AHWR) is a pressure tube type light water cooled heavy water moderated Boiling Water Reactor (BWR) with natural circulation at all power levels. It has parallel inter-connected loops with 452 boiling channels in the Main Heat Transport (MHT) system configuration. These multiple (four) interconnected loops influence the Steam Drum (SD) level control adversely. Such a behavior has not been reported in the open literature. The MHT configuration has been chosen based on comprehensive overall design requirements and certain Postulated Initiated Events (PIEs). This does not allow the partitioning of the Common Reactor Inlet Header (CRIH). If partitioning of the CRIH into four segments is allowed then, it will make each loop independent. Then the SD level control problems subside as the unaccounted interaction among the loops is eliminated. It has also been observed that the open loop response is stable, non-oscillatory and non-diverging for a step change in the feed flow rates. A conventional individual 3-element SD level controller cannot account for the highly coupled and interacting behaviors, of the four loops and SD levels. To overcome these interactions it is proposed to interconnect all the four steam drums in the liquid and vapor regions respectively. The influence of the interconnect configuration and the level controller are studied in detail to find a robust solution. The response obtained for unsymmetrical core power disturbances shows that the SD levels do not diverge and quickly settle to the set points assigned with SD interconnect. The proposed scheme also works well for most of the PIEs considered.

The Prospects of Carrying and Releasing Drugs Via Biodegradable Magnesium Foam

AbstractPowder metallurgy technology was used to produce magnesium foams in order to evaluate their ability to perform as a solid biodegradable platform for drug delivery. The amount and delivery time of the released drug (gentamicin) was controlled by the level of space‐holding particles (spacer) that was mixed with the magnesium powder prior to the sintering process. Metallurgical examination of the magnesium foams was carried out using optical and scanning electron microscopy (SEM) and X‐ray diffraction analysis. Microtomography CT analysis was used to evaluate the structural characteristics of the magnesium foams and their internal interconnected porosity configuration. The corrosion behavior of the magnesium foams was evaluated by immersion test in a simulated physiological environment (PBS solution). The absorption of gentamicin was obtained by immersing magnesium foams in concentrated gentamicin solutions within a vacuum chamber, followed by water evaporation. The detection of gentamicin in PBS solution was carried out using a Fluorescence Polarimetry analyzer. The results show that the release profile of gentamicin from magnesium foam with 10 and 25% spacer in PBS solution was in accord with common dissolution kinetics of an active ingredient from polymeric drug delivery systems.

Roll- and pitch-plane coupled hydro-pneumatic suspension

Passive fluidically coupled suspensions have been considered to offer a promising alternative solution to the challenging design of a vehicle suspension system. A theoretical foundation, however, has not been established for fluidically coupled suspension to facilitate its broad applications to various vehicles. The first part of this study investigates the fundamental issues related to feasibility and properties of the passive, full-vehicle interconnected, hydro-pneumatic suspension configurations using both analytical and simulation techniques. Layouts of various interconnected suspension configurations are illustrated based on two novel hydro-pneumatic suspension strut designs, both of which provide a compact design with a considerably large effective working area. A simplified measure, vehicle property index, is proposed to permit a preliminary evaluation of different interconnected suspension configurations using qualitative scaling of the bounce-, roll-, pitch- and warp-mode stiffness properties. Analytical formulations for the properties of unconnected and three selected X-coupled suspension configurations are derived, and simulation results are obtained to illustrate their relative stiffness and damping properties in the bounce, roll, pitch and warp modes. The superior design flexibility feature of the interconnected hydro-pneumatic suspension is also discussed through sensitivity analysis of a design parameter, namely the annular piston area of the strut. The results demonstrate that a full-vehicle interconnected hydro-pneumatic suspension could provide enhanced roll- and pitch-mode stiffness and damping, while retaining the soft bounce- and warp-mode properties. Such an interconnected suspension thus offers considerable potential in realising enhanced decoupling among the different suspension modes.

A Workload-Adaptive and Reconfigurable Bus Architecture for Multicore Processors

Interconnection networks for multicore processors are traditionally designed to serve a diversity of workloads. However, different workloads or even different execution phases of the same workload may benefit from different interconnect configurations. In this paper, we first motivate the need for workload-adaptive interconnection networks. Subsequently, we describe an interconnection network framework based on reconfigurable switches for use in medium-scale (up to 32 cores) shared memory multicore processors. Our cost-effective reconfigurable interconnection network is implemented on a traditional shared bus interconnect with snoopy-based coherence, and it enables improved multicore performance. The proposed interconnect architecture distributes the cores of the processor into clusters with reconfigurable logic between clusters to support workload-adaptive policies for inter-cluster communication. Our interconnection scheme is complemented by interconnect-aware scheduling and additional interconnect optimizations which help boost the performance of multiprogramming and multithreaded workloads. We provide experimental results that show that the overall throughput of multiprogramming workloads (consisting of two and four programs) can be improved by up to 60% with our configurable bus architecture. Similar gains can be achieved also for multithreaded applications as shown by further experiments. Finally, we present the performance sensitivity of the proposed interconnect architecture on shared memory bandwidth availability.

Single-Conductor Transmission-Line Model of Multiwall Carbon Nanotubes

The equivalent single-conductor model of a multiwall carbon nanotube (MWCNT) interconnect is derived analytically from the rigorous formulation of the complex multiconductor transmission-line propagation equations. The expressions of the per-unit-length (p.u.l.) equivalent quantum capacitance and kinetic inductance are obtained in closed form. A new accurate approximated expression of the equivalent p.u.l. quantum capacitance is proposed. It is demonstrated, through analytical derivations and numerical calculations, that the new expression is valid for the most of MWCNT interconnect configurations, whereas a more simplified formula, obtained on the basis of qualitative considerations, produces high approximation errors. The proposed model is solved in both the frequency and time domains. Transient analyses are performed in order to predict the attenuation and time delay of a pulse signal transmitted along an MWCNT as a function of the tube length and number of shells. Simulation results are also compared with measured data available in literature.

Nano- and micrometer-scale thin-film-interconnection failure theory and simulation and metallization lifetime prediction, Part 1: A general theory of vacancy transport, mechanical-stress generation, and void nucleation under electromigration in relation to multilevel-metallization degeneration and failure

The physical principles are considered of on-chip interconnection degeneration and failure in sub-1-µm technologies from the viewpoint of multilevel-metallization reliability. A general theory and simulation results are presented that deal with electromigration-induced failure of thin-film conducting tracks on the micro- and nanometer scales. They provide a detailed treatment of micro-, meso-, and nanoscopic mechanisms underlying the deformation and breaking of actual interconnection configurations. Parts 1 and 2 contain (i) the derivation and analysis of basic kinetic equations; (ii) the formulation and solution of three-dimensional boundary-value problems representing the transport of vacancies (both in the bulk and along grain boundaries) and the development of deformation and stress; (iii) models of void nucleation and development; (iv) an analysis of a multilevel-metallization lifetime; and (v) the identification of potential break locations in a multilevel metallization in relation to current density, metallization structure and layout, temperature, and the grain structure of the conducting material. Part 3 deals with electromigration in doped on-chip polycrystalline interconnections in terms of lengthening their lifetime. To predict electromigration resistance, models are constructed that represent the influence of texture and other grain-boundary properties on the effective charges of native and dopant ions.

Unidirectional Binding of Clostridial Collagenase to Triple Helical Substrates

Histotoxic clostridia produce collagenases responsible for extensive tissue destruction in gas gangrene. The C-terminal collagen-binding domain (CBD) of these enzymes is the minimal segment required to bind to collagen fibril. Collagen binding efficiency of CBD is more pronounced in the presence of Ca(2+). We have shown that CBD can be functional to anchor growth factors in local tissue. A (1)H-(15)N HSQC NMR titration study with three different tropocollagen analogues ((POG)(10))(3), ((GPOG)(7)PRG)(3), and (GPRG(POG)(7)C-carbamidomethyl)(3), mapped a saddle-like binding cleft on CBD. NMR titrations with three nitroxide spin-labeled analogues of collagenous peptide, (PROXYL-G(POG)(7)PRG)(3), (PROXYL-G(POG)(7))(3), and (GPRG(POG)(7)C-PROXYL)(3) (where PROXYL represents 2,2,5,5-tetramethyl-l-pyrrolidinyloxy), unambiguously demonstrated unidirectional binding of CBD to the tropocollagen analogues. Small angle x-ray scattering data revealed that CBD binds closer to a terminus for each of the five different tropocollagen analogues, which in conjunction with NMR titration studies, implies a binding mode where CBD binds to the C terminus of the triple helix.

Spiritual Intelligence and Transformational Leadership: A New Theoretical Framework

The purpose of this paper is to establish a connection between spiritual intelligence and transformational leadership in an effort to encourage further debate about the legitimacy of spiritual intelligence in educational discourse. In this context we define spiritual intelligence as an interconnected configuration of affective orientations intimately linked to create meaning through connecting ideas, events, and persons rather than to a specific religious tradition or orientation. An exploration of the meaning of transformational leadership in education in K-12 settings provides the basis for the development of a synthesis from a new perspective of two concepts that empower the dispositions of leadership impacting school culture.

Flip-Chip Interconnect for Coplanar Strip Lines

A flip-chip interconnect configuration with coplanar strip (CPS) lines on printed circuit boards (PCBs) is reported for millimeter-wave applications. For CPS lines, the signal and ground electrodes both lie on the top surface of a chip or substrate. The flip-chip configuration was designed and implemented using a test chip on a dielectric board. Geometrical parameter analysis was carried out using full-wave simulation and equivalent circuit model for wideband performance. The chip was connected to the board using solder bumps. For a typical flip-chip assembly, the measured insertion loss is less than 3dB for frequencies of up to 35GHz and the return loss is higher than 15dB for frequencies of up to 29GHz using CPS flip-chip configuration.

Micro-stamped surfaces for the patterned growth of neural stem cells

We present a method for patterning neural stem cells based on pre-patterning polypeptides on a cell-repellent surface (poly(ethylene) oxide-like, PEO-like, plasma-deposited films). The method ensures cell attachment and stability for several weeks, as well as it allows cell migration and differentiation. Various patterns of ∼1 nm thick cell adhesive poly- l-lysine (PLL) have been created on a cell-repellent PEO-like matrix by microcontact printing using different array configurations and printing conditions. The cell-repellent property of PEO-like film determined the confinement of the cells on the printed patterns. Optimization of the printing method showed that the most homogeneous patterns over large areas were obtained using PLL diluted in carbonate buffer (100 m m) at pH 8.4. Neural stem cells cultured on the PLL patterns in low serum and in differentiating medium over 20 days exhibited a good confinement to the polypeptide domains. The number of cells attached increased linearly with the micro-stamped PLL area. The cells were able to extend random axon-like projections to the outside of the patterns and presented high amount of ramifications when cultured in differentiating medium. Migration and axon-like outgrowth have been successfully guided by means of an interconnected squares configuration. The surfaces are suitable for controlling the patterning of stem cells and provide a platform for the assessment of the way how different cell arrangements and culture conditions influence cell interactions and cell developmental processes.

Development of a suitable model for characterizing photovoltaic arrays with shaded solar cells

The aim of this study is to investigate the effects of non-uniform solar irradiation distribution on energy output of different interconnected configurations in photovoltaic (PV) arrays. In order to find which configuration is less susceptible to mismatch effects, a PV module model is developed. This model can take into consideration the effects of bypass diodes and the variation of the equivalent circuit parameters with respect to operating conditions. The proposed model can provide sufficient degree of precision as well as solar cell-based analysis in analyzing large scale PV arrays without increasing the computational effort. In order to produce more reliable and robust simulations, improved and extended algorithms are presented. Some results are discussed in detail and some recommendations are extracted by testing several shading scenarios.

Application-Dependent Testing of FPGAs

Testing techniques for interconnect and logic resources of an arbitrary design implemented into a field-programmable gate array (FPGA) are presented. The target fault list includes all stuck-at, open, and pair-wise bridging faults in the mapped design. For interconnect testing, only the configuration of the used logic blocks is changed, and the structure of the design remains unchanged. For logic block testing, the configuration of used logic resources remains unchanged, while the interconnect configuration and unused logic resources are modified. Logic testing is performed in only one test configuration whereas interconnect testing is done in a logarithmic number of test configurations. This approach is able to achieve 100% fault coverage