Networking Structure Research Articles

Atomic-level modeling and computation of intergranular glassy film in high-purity Si3N4 ceramics

A model for intergranular glassy film (IGF) at grain boundaries in Si3N4 is proposed. The model agrees well with experimental information available. Although it has periodicity, atomistic simulations using the model enable to elucidate the rationale for the presence of the IGF. Amorphous models obtained by molecular dynamics based on the crystalline model enable atomistic simulations to address further issues related the IGF: it is found that the IGF plays an important role to relieve the strain due to misorientation of adjacent Si3N4 grains, that equilibrium IGF thickness is determined by the balance between the strain relief and energy penalty of silicon oxynitride constituting the IGF, and that both O and N are needed in the IGF to provide flexibility of networking structure of the IGF as well as to minimize chemical mismatch between adjacent Si3N4 grains and the IGF. Equilibrium IGF composition is successfully estimated for the first time.

Scalable and Cost-Effective Interconnection of Data-Center Servers Using Dual Server Ports

The goal of data-center networking is to interconnect a large number of server machines with low equipment cost while providing high network capacity and high bisection width. It is well understood that the current practice where servers are connected by a tree hierarchy of network switches cannot meet these requirements. In this paper, we explore a new server-interconnection structure. We observe that the commodity server machines used in today's data centers usually come with two built-in Ethernet ports, one for network connection and the other left for backup purposes. We believe that if both ports are actively used in network connections, we can build a scalable, cost-effective interconnection structure without either the expensive higher-level large switches or any additional hardware on servers. We design such a networking structure called FiConn. Although the server node degree is only 2 in this structure, we have proven that FiConn is highly scalable to encompass hundreds of thousands of servers with low diameter and high bisection width. We have developed a low-overhead traffic-aware routing mechanism to improve effective link utilization based on dynamic traffic state. We have also proposed how to incrementally deploy FiConn.

Monolithic Macroporous Carbon Cryogel Prepared from Natural Polymers

In this study, monolithic macroporous carbon cryogels with a surface area of 117.1 m/g, a sheet resistance of 23 Ω/ and a contact angle of 140◦ were prepared from a bacterial cellulose membrane. The microscopic morphology of the cryogels contained a macroporous networking structure with a large number of micropores. Before polytetrafluoroethylene treatment, the carbon cryogels were very hydrophobic because of the large number of micropores on the surfaces of the cryogels. Therefore, the carbon cryogels exhibited great potential for applications as a gas diffusion layer in fuel cells because of their high electrical conductivity, macroporous structure and hydrophobicity.

Idea adaption, social interactions and small world networks: An Australian study

Organizations need a capacity to adapt new ideas and therefore require the means to visualize them. Idea adaptation is understood to be a social interaction process. This idea of adaption capacity might therefore be understood and managed by visualizing it using small world theory. This paper will explain how and why small world visualization can be used to represent idea adaption capability. The small world structure is preferred because it represents loose coupling and distinguishes the need for both discipline-specific knowledge (strong ties) and interaction with alternative ideas (structural holes, weak ties). Furthermore, it appears to be the evolved preferred natural networking structure for idea sharing. An illustration of how the small world structure might be visualized is provided by mapping the idea adapting networks of two loosely coupled organizations.

Configuration and conformation of taibaihenryiin T isolated from Phlomis umbrosa

Taibaihenryiin T was isolated for the first time from Phlomis umbrosa Turcz, and its structure was elucidated on the basis of IR and NMR spectra analysis. Its molecular configuration, conformation, and crystal structure were also characterized by X-ray structure analysis. The infrequency of the C–O–O–C group is manifested in this molecular configuration, and hydrogen bonding assembles the molecules into a three-dimensional networking structure in the crystal.

Effect of graphite sizes and carbon nanotubes content on flowability of bulk-molding compound and formability of the composite bipolar plate for fuel cell

This study investigates the flowability of the bulk-molding compound (BMC) on composite bipolar plates containing graphite content from 70 to 80 wt% with different graphite sizes. A small quantity (from 0.25 to 2 wt%) of multi-walled carbon nanotubes (MWCNT) is also added. Findings show that the flowability of BMC material decreases with decreasing graphite size and with increasing graphite content. The BMC material containing large size graphite (177–125 μm) entirely exhibits a relatively higher flowability within the analysis graphite contents, in the range of 73.3–11.3 cm, compared to the small size (74–45 μm), in which flowability is in the range of 40.3–6.67 cm. Further adding MWCNT causes decreased flowability of the BMC material especially when the percolated networking structure is formed through the resin. Therefore, with flowability below 10 cm, the formability of a large area (300 mm × 300 mm × 3 mm) or thin (100 mm × 100 mm × 0.5 mm) composite bipolar plate shows a large area of surface porosity or visible defects. Results indicate that the flowability of the thermoset-based BMC material is an important design parameter to fabricate cost-effective, large, or thin composite bipolar plates.

Too Much E-Mail Decreases Job Satisfaction

In a 50 people company we compared various performance metrics with social networking structure obtained by mining e-mail archives. We also calculated e-mail responsiveness and conducted an individual job satisfaction survey. We identified patterns of productive and less-productive e-mail usage. Results indicate that central network position reduces e-mail responsiveness, while this position in the organization's social network also seems to be correlated with lower job satisfaction. In particular, the team which sent and received the most e-mail reported the lowest job satisfaction.

Stress and strain in DLC films induced by electron bombardment

Radiation induced stress and strain have been investigated in amorphous hydrogenated DLC films after their exposure to high-energy (12 MeV) electrons, produced in the medical linear accelerator. DLC structures of different hydrogen contents and thickness, deposited from acetylene gas onto Si<111> wafers in the two-chamber plasmotron system were used in this investigation. Optically levered laser technique was used to measure the radius of curvature of the investigated DLC films and residual stress in the film was determined. Surface morphology of DLC films was defined by AFM “Nanotop-206”. Microhardness measurements were performed using MTS Nanoindenter G200. Bonding structure of the DLC films was analysed using the Raman scattering spectroscopy. It was found that the bombardment of DLC films with high-energy electrons introduced additional residual stress in all investigated samples. However, stress saturation tendency was observed after some fractions of the irradiation. Radiation induced stress was lower in the samples with well-organized networking structure, depending on technological conditions of the film growth. Significant deterioration of the mechanical properties of DLC films after their bombardment with high-energy electrons was not observed. Radiation induced changes in irradiated DLC films are discussed on the basis of the results of measurements.

Properties of bacterial cellulose produced in a pilot-scale spherical type bubble column bioreactor

The saccharogenic liquid obtained by the enzymatic saccharification of food wastes was used as a medium for production of bacterial cellulose (BC). The enzymatic saccharification of food wastes (SFW) was carried out by the cultivation supernatant of Trichoderma inhamatum KSJ1. 5.6 g/L of BC was produced in a new modified 50 L bubble column bioreactor by Acetobacter xylinum KJ1. The productivity was similar to that of a modified 10 L bubble column bioreactor (5.8 g/L). When pure oxygen was supplied into the scaled-up culture conditions, 6.8 g/L (12% enhancement) of BC was produced, indicating a very useful method for BC mass production. The oxygen uptake rate (OUR) and q O2 (specific oxygen uptake rate) were 0.214 mg-DO/L·min and 0.257 mg-DO/g-cell·min, respectively. The physical properties, such as morphology, molecular weight, crystallinity, and tensile strength of BCs produced in static culture (A), 10 L (B) and 50 L (C) modified bubble column cultures were investigated. All BCs showed fibrils with highly networking structure. The number average molecular weight of BCs in A, B and C was 2,314,000, 1,878,000, and 1,765,000, respectively. All of the BCs had a form of cellulose I representing pure cellulose. The relative degree of crystallinity showed the range of 79.6–86.0%. Tensile strengths of BC sheet in A, B and C were 1.75, 1.21, and 1.19 kg/mm2, respectively. In conclusion, BC production by the modified bubble column culture mode of 50 L brought more favorable results in terms of the physical properties and its ease of scale-up.

Fit for purpose – a regional case study in primary care research partnerships

AimsTo describe the context, mechanisms and outputs of a regional primary care partnership for research facilitation over a three-year period, and evaluate factors which were likely to be worth replicating in the new UK Clinical Research Network (UKCRN) structures.BackgroundThe revision of NHS research and development structures into the UKCRN has presented organizational challenges to pre-existing partnerships. This raises questions of whether pre-existing arrangements had already delivered effective research facilitation in NHS settings, and makes evaluation of successful practice a crucial part of organizational learning for the current management of research delivery in the UK.MethodsA mixed methods case study in one R&amp;D consortium (Norfolk and Waveney, England). Using a model of realistic evaluation, we analysed context, mechanisms, working practices, and outcomes for research delivery in the primary care context – covering key priorities of research governance and ethics, hosting and recruiting to studies, and training and support approaches.FindingsFrom January 2005 to December 2007, 35 general practices opted into a host practice research network, each hosting an average of 10 studies over that period, with 278 projects being active overall. By the last year, an extension of network activity to all practices in Norfolk, Great Yarmouth and Waveney had led to 96% of all practices delivering at least one study, and a turnaround, from application to commencement of approved studies, of 28 days for 74% of studies. This level of activity can act as a baseline for future UKPCRN activities, and the factors associated with it may be helpful for others seeking to provide an effective networking structure. The larger structures of the new UKCRN regional networks will be able to draw on extensive good practice in some areas, and should be sure to preserve these, as they may already be fulfilling the important goals for which UKCRN was created.

Chemical vapor infiltration (CVI) SiC whisker on carbon woven fabric for filter applications

β-silicon carbide whiskers have been synthesized on a carbon fabric by a vapor-solid (VS) mechanism using the Chemical Vapor Infiltration (CVI) process. Optimum processing conditions for SiC whisker growth were determined by mapping of SiC deposition behavior. SiC was deposited on a carbon fabric substrate as a film or whiskers, depending on processing conditions. The mean diameter and line density of the whiskers was the highest at an input gas ratio of 50. As temperature increases, the mean diameter of the whiskers increased and the line density of whiskers decreased. In the optimum processing conditions, whiskers grew uniformly with high growth density and formed a networking structure between each of the carbon filaments resulting in a structure suitable for filter applications.

Extracellular HSP70 blocks CD40L‐induced apoptosis and tubular formation in endothelial cells

Recent studies have shown that CD40, a key player in angiogenesis and tubular formation, is an extracellular receptor of the heat shock protein 70 (HSP70)-peptide complex in endothelial cells. The aim of the present study was to determine the effect of extracellular HSP70 treatment on CD40L-suppressed apoptosis and CD40L-induced tubular formation in human umbilical vein endothelial cells (HUVEC). The apoptotic index of CD40L-stimulated HUVEC with or without recombinant human HSP70 was evaluated using terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling assay analysis. Binding of HSP70-peptide complex to CD40 on HUVEC was determined by double-labeling immunofluorescence methods. To evaluate the biological activity of CD40 engagement pretreated with rhHSP70 (0.5, 1 and 3 ng/mL), the extent of new capillary-like networking structure (tubular formation) formation in HUVEC was counted using an Olympus digital camera. Vascular invasion into MNK-28 cell clusters was assessed by counting the number of tubular structures extending from the HUVEC into growth factor-depleted Matrigel. Scores for CD34, HSP70 and CD40L expression levels in gastric cancer tissues were determined by immunostaining. CD40L stimulation inhibited vincristine-induced apoptosis of HUVEC in a dose-dependent manner. Extracellular HSP70 treatment significantly blocked the inhibition of apoptosis by CD40L in HUVEC exposed to vincristine. HSP70-peptide complex bound to CD40 on HUVEC. Extracellular HSP70 treatment also significantly reduced CD40L-induced tubular formation in a dose-dependent manner. HSP70 treatment also suppressed invasive tubular formation into MKN-28 cells clusters by CD40L-activated HUVEC. There was a significant relationship between CD40L expression levels and microvessel density; however, the relationship between HSP70 expression level and microvessel density in gastric cancer tissues was not significant. Extracellular HSP70 treatment blocks CD40L inhibition of apoptosis and CD40L induction of tubular formation in HUVEC.

Pyrolysis of furfural-acetone resin as matrix precursor for new carbon materials

In order to increase the understanding of the pyrolysis mechanism, Fourier transform infrared spectroscopy (FT-IR) and thermogravimetry-mass spectrometric coupling technique (TG-MS) were used to study the pyrolysis behavior of furfural-acetone resin used for new carbon materials. The curing and carbonization mechanisms of furfural-acetone resin were mainly investigated; structural changes and volatile products evolved during pyrolysis were analyzed. The results indicate that, during pyrolysis of furfural-acetone resin adding 7% (mass fraction) phosphorous acid as curing agent, the rupture of C—O bond in the five-membered heterocycle firstly takes place to release oxygen atoms and then does the C—H bond, which enable the molecular chain to cross-link and condense, then lead to the formation of three dimensional networking structure. With the increase of pyrolyzing temperature, the scission of methyl and the opening of furan ring are generated. As a result, the recomposition of molecular chain structure is generated and a hexatomic fused ring containing double bonds is built. The main volatile products during pyrolysis of furfural-acetone resin are H2O, and a small mount of CO, CO2 and CH4. At elevated temperatures, dehydrogenation takes place and hydrogen gas is evolved.

Networking amorphous phase reinforced titanium composites which show tensile plasticity

Titanium matrix composites reinforced by an in situ formed networking amorphous phase have been prepared directly in the form of as-cast ingots. The composites show significant compressive and tensile plasticity. In contrast to the highly localized plasticity for most monolithic amorphous alloys, the tensile deformation of the current composites distributes uniformly over the entire specimen as a consequence of substantial work (strain) hardening. The formation mechanism of the networking structure, as a result of well-separated two-step solidification of the current alloy melts, have possible implications for composite synthesis in other alloy systems.

Crystal and Molecular Structure of Songorine from the Root of Aconitum szechenyianum Gay

Songorine was isolated from the root of Aconitum szechenyianum Gay and its crystal structure was determined by X-ray single crystal diffraction. The compound compactly packs in an orthorhombic unit cell in the P212121 space group with unit cell dimensions a = 9.7733(7) A, b = 13.4892(9) A, c = 14.8097(10) A, V = 1952.4(2) A3 and Z = 4. A series of intricate hydrogen bonds assemble the title compound into a three-dimensional networking structure.

Modification of amorphous DLC films induced by MeV photon irradiation

Modification of the properties of amorphous diamond-like carbon (DLC) coatings irradiated by MeV photons from medical linear accelerator has been investigated. DLC structures of different content and thickness, synthesized under different technological parameters at room temperature using direct ion deposition (cold cathode) method were used for the investigation. Properties of the irradiated carbon films were studied using UV/VIS spectrometry and laser ellipsometry. Bonding structure of the samples was analyzed by Fourier transform infrared (FTIR) spectrometry and Raman scattering (RS) spectroscopy. Investigated DLC films indicated increased optical transparency which was different for the films with different networking structure. No significant structural changes were found in irradiated SiOx-containing and additionally N2 co-doped DLC films. Reduction of permittivity was observed in all irradiated samples.The results of investigation are analyzed in accordance with the registered radiation induced changes in investigated samples and possible model of the X-ray photon interaction with amorphous DLC films is discussed.

Effect of pH on structural and morphological properties of spray deposited p-type transparent conducting oxide CuAlO 2 thin films

CuAlO 2 due to its delafossite structure is known to exhibit p-type conductivity. p-CuAlO 2 thin films have been prepared using spray pyrolysis technique. The films prepared using precursor solutions with different pH values have been characterized for optical, structural and morphological properties. The X-ray diffractograms of the films deposited using precursor solution with pH 3.7 do not show any peaks, these suggest the amorphous nature of the films. On the other hand, the films deposited with pH 1.5 show the peaks of CuAlO 2 with delafossite crystal structure. Thus the pH of the solution is playing a crucial role in giving the crystalline product of the material of interest. Tauc's plot of the film deposited using precursor solution of pH 3.7 shows the absorption edge at 3.71 eV and the film deposited with solution pH 1.5 shows the absorption edge at 3.64 eV, corresponding to the direct band gap of CuAlO 2. This confirms the formation of CuAlO 2. The surface morphology of the films shows the novel networking structure. Compositional analysis done using Energy dispersive X-ray spectrum shows an excess of oxygen that should be favorable for giving the p-characteristics.

화학증착 탄화규소 휘스커에 의한 다공성 코디어라이트의 기공구조 개질 및 특성평가

The main purpose of this study is enhancing the filtering efficiency, performance and durability of filter by growing SiC whiskers on cordierite honeycomb substrate. The experiment was performed by Chemical Vapor Infiltration (CVI) in order to control pore morphology of substrate. Increasing the mechanical strength of porous substrate is one of important issues. The formation of “networking structure” in the pore of porous substrate increased mechanical strength. The high pressure gas injection to the specimen showed that a little of whiskers were separated from substrate but additional film coating enhanced the stability of whisker at high pressure gas injection. Particle trap test was performed. More nano-particle was trapped by whisker growth at the pore of substrate. Therefore it is expected that the porous cordierite which deposited the SiC whisker will be the promising material for the application as filter trapping the nano-particles.

Synthesis of 7,4′-Bis-(hydroxyl)-8,3′,5′-tris-(hydroxymethyl)isoflavone and Crystal Structure of its Ester

7,4′-bis-(hydroxyl)-8,3′,5′-tris-(hydroxymethyl)isoflavone (I) and its ester were synthesized and examined by IR, element analysis and 1H NMR. The crystal of 7,4′-bis-(acetyl oxide)-8,3′,5′-tris-(acetoxymethyl)isoflavone (II) was studied by X-ray diffraction. (II) crystallizes in the monoclinic with space group P2 1 /c. a = 17.987(3) A, b = 17.972(3) A, c = 8.4087(11) A, β = 97.703(3)°, V = 2693.7(6) A3 and Z = 4. The molecular structure of the ester consists of a benzopyranone moiety, a phenyl moiety, two acetyl oxides and three acetoxymethyl groups. Hydrogen bonds and aromatic stacking interactions link the ester into a two-dimensional structure. 7,4′-bis-(hydroxyl)-8,3′,5′-tris-(hydroxymethyl)isoflavone and its ester were synthesized and examined by IR, element analysis and 1H NMR. The result of the ester’s crystal structure showed that hydrogen bonding and aromatic π–π stacking assemble the ester into a two-dimensional networking structure.

Synthesis and Structure of 2-Ferrocenylmethylidenehydrazono-1,3-dithiolane

The title compound, 2-Ferrocenylmethylidenehydrazono-1,3-dithiolane was synthesized by ferrocene- carboxaldehyde with 2-hydrazono-1,3-dithiolane and characterized by elemental analysis, 1H NMR, IR, UV-Vis and single crystal XRD. The crystal belongs to orthorhombic, space group Fdd2 with unit cell parameters a = 27.487(4) A, b = 35.239(6) A, c = 6.0517(9) A, V = 5861.7(16) A3, Z = 16, Dc = 1.497, Mr = 330.24, μ = 1.300 mm−1, F(000) = 2720, R 1 = 0.0413, and wR 2 = 0.0753. The molecule is the anti-rotamer of the trans-isomer and every molecule joins each other to a zig-zag chain through the intermolecular unclassical hydrogen-bonds of C(7)–H(7)···N(1) (3.449(8) A, 172°). Further every chain self-assembles into a three-dimensional networking structure via another intermolecular unclassical hydrogen-bonds of C(1)–H(1A)···π/Cg (3.597(7) A, 143°) and the weak inter molecular interaction forces of C(4)–H(4)···S(1) (3.742(7) A, 139°) and C(14)–H(14)···H(6) (3.080(7) A, 134°). Synthesis and Structure of 2-Ferrocenylmethylidenehydrazono-1,3-dithiolane Yonghong Liu, Xiangqian Dai, Xiaolan Liu, Wei Xu, and Rong Guo College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, 225002, P.R. China The title compound was synthesized and characterized by elemental analysis, 1H NMR, 13C NMR, IR, UV-Vis and single crystal XRD.