Interphase Distance Research Articles

The Effect of Solidification Rate on the Corrosion Resistance of Die-Cast AZ91 Magnesium Alloy.

To increase the utilization of die-cast Mg alloys with various shapes in a variety of environments, the corrosion behaviors of commercial die-cast Mg alloys with different thicknesses were investigated in neutral and alkali solutions at ambient temperature. A decrease in the thickness of a specimen leads to an increase in cooling and solidification rates, which, in turn, decreases the size of the eutectic β phases and the interphase distance, thus improving the hardness of the specimen. Specimens with relatively large β phases were more corroded under neutral conditions due to severe galvanic corrosion at the interface between α-Mg and the β phases, whereas they were protected by passivation films formed on the substrate in the alkaline solution. However, in the case of the alloy with thin thickness and high solidification rate, the fine β phases improved corrosion resistance by forming a net structure that acted as a barrier to corrosion propagation of the α matrix. These results suggest that the size and distribution of the eutectic phases should be appropriately controlled, depending on the environment.

Investigation on bitumen-epoxy interface in cold mixed epoxy bitumen using experimental observation and molecular dynamics simulation

Cold-mixed epoxy bitumen (CEB) has gained much importance due to the demand for high-performance materials in pavement construction. In addition to the curing process of epoxy bitumen, which has been comprehensively investigated, the bitumen-epoxy interface also critically influences the mechanical properties of CEBs. Therefore, this study explored the bitumen-epoxy interface based on experiments and molecular dynamic simulation. In the experiment part, the Fourier Transform Infrared Spectroscopy (FTIR) was adopted to characterize the chemical reaction that occurred in the epoxy bitumen. Besides, this study used the fluorescent microscope (FM) to experimentally observe the morphological evolution of CEBs as the curing proceeded. Concerning the molecular dynamic simulation, four simplified epoxy models with varying characteristics and their related bitumen-epoxy interface models were considered in the simulation. The results indicated that the curing process would increase the average molecular weight and the molecular polarity. Experimental observation of the bitumen-epoxy interface revealed that the formation of the bitumen-epoxy interface included two primary processes, which were the coarse-grained process and particle expansion process. Simulation results showed that the bonding between bitumen and epoxy was composed of van der Waals force and hydrogen force. Besides, the interphase distance was positively correlated with average molecular weight and reaction degree.

Study on the influence of interphase spacers on ice shedding of three-phase iced eight-bundled transmission lines

Sudden ice shedding from three-phase iced eight-bundled transmission lines with inverted-triangle arrangement was numerically and experimentally modeled. The staggered-arrangement groups and compact-arrangement groups (including triangular and V-shaped structures) of interphase spacers were considered to investigate the inhibition effects on ice shedding. Based on the similarity theory, a modification method was proposed to determine the natural frequency similarity between model and prototype. According to the dynamic tension, interphase distance, and jumping height, the reduction rate of dynamic tension, interphase-distance ratio, reduction rate of jumping height, and comprehensive reduction rates were determined for different arrangements of the interphase spacers. The inhibition effects of different factors on ice shedding were discussed for different lines, including the position and number of transmission lines for the ice-shedding phase and the various possible arrangements of interphase spacers. Deicing schemes for the different line configurations were proposed, and the best arrangement of interphase spacers was selected for each case. The present study provides a theoretical foundation for selecting an appropriate arrangement of interphase spacers during ice shedding.

The Impact of Interphase Spacers on Galloping Control of Three-Phase Iced Eight-Bundled Transmission Lines: An Experimental Study

This study aims to conduct galloping experiments using a full aeroelastic model to investigate the galloping controlling effects of interphase spacers with different kinds of arrangements on three-phase iced eight-bundled transmission lines. A low-speed wind tunnel was designed and built to assess the compact transmission lines on a single span. The similarity conditions between the aeroelastic model and the prototype were determined by the similarity theory and the proposed modification method. Four common arrangements of interphase spacers were considered. Compared with the situation without interphase spacers, the composite amplitude reduction rate of the first two modes and amplitude reduction rate varying with wind speed were evaluated. Then, the anti-galloping effects of interphase spacers were investigated and the controlling effects of interphase spacers on the interphase distance were analyzed. Besides, the corresponding arrangements under different conditions were determined. In addition, the galloping phenomena varying with wind speed were explored. The results suggested that their galloping phenomena were changed because of the effects of interphase spacers, and coupling effects of interphase spacers with different arrangements were different. This research could be used to estimate the positions of interphase spacers and offered a theoretical foundation for the anti-galloping design of transmission lines.

Comparative assessment of apical sealing ability of three different endodontic sealers: A scanning electron microscopic study

AimThe present in vitro SEM study compared the apical sealing ability of three different endodontic sealers used in single cone obturation technique. Material and method45 freshly extracted mandibular premolars with single canal and fully formed apices were selected. The samples were decoronated at/below the cementoenamel junction (CEJ) obtaining root lengths of 15 mm. The samples were instrumented using ProTaper rotary file system SX-F2. Following instrumentation the samples were randomly divided in three different groups for three different sealers to be used in single cone obturation technique. Group 1 EndoSequence BC, Group 2 GuttaFlow 2 and Group 3 AH Plus. The sealers were allowed to set completely. Following this the samples were longitudinally sectioned at the apical third and gold sputtered for SEM evaluation. The interphase between the radicular dentin and the root canal filling material were obtained in micrometers (μm) from the SEM images. Statistical analysis was performed. ResultsThe groups exhibited a statistically significant difference (p < 0.01). Group 3 presented with the highest interphase distance (p < 0.01), whereas Group 1 and 2 exhibited a statistically similar values (p > 0.05). ConclusionThe GuttaFlow 2 and Endosequence BC endodontic sealers showed better adaptation to the radicular dentin as compared to AH Plus sealer.

An Interphase Distance Relaying Algorithm for Series-Compensated Transmission Lines

A new interphase distance relaying algorithm for series-compensated transmission lines is proposed in this paper. The fault impedance can be correctively calculated using the proposed algorithm without requirement of the parameters of series capacitor device. The series capacitor can be simplified as a linearized impedance during the fault period, but its parameters can be used as variables in fault loop equations. The real-time digital simulator tests show that the proposed algorithm can obtain more accurate results than other traditional distance relaying algorithms for series-compensated transmission lines.

Research on Sag and Phase-Phase Space Change by Installing Interphase Spacers for Transmission Lines

Installation of inter-phase spacer can effectively protects against line fault caused by conductor galloping, non-synchronous swing and sleet jump etc large amplitude vibration, but sag of the conductor is changed if inter-phase spacer is installed. And installation of initial inter-phase spacer will cause change of inter-phase distance, which cause difficulty of successive installation. The empirical equation can’t accurately analyze change of the inter-phase distance caused during installation of the inter-phase spacer. In this paper, accurate conductor installation inter-phase spacer analysis model is established with non-linear finite element method. Change of the conductor sag after installation of the inter-phase spacer is calculated, and influence on inter-phase distance caused by different installation sequence is analyzed. The research result provides effective analysis method for length control of actual line installed inter-phase spacers, and ensures manufacturing and successful installation of the inter-phase spacer.

CBFB and MYH11 in inv(16)(p13q22) of acute myeloid leukemia displaying close spatial proximity in interphase nuclei of human hematopoietic stem cells

To gain a better understanding of the mechanism of chromosomal translocations in cancer, we investigated the spatial proximity between CBFB and MYH11 genes involved in inv(16)(p13q22) found in patients with acute myeloid leukemia. Previous studies have demonstrated a role for spatial genome organization in the formation of tumorigenic abnormalities. The nonrandom localization of chromosomes and, more specifically, of genes appears to play a role in the mechanism of chromosomal translocations. Here, two-color fluorescence in situ hybridization and confocal microscopy were used to measure the interphase distance between CBFB and MYH11 in hematopoietic stem cells (HSCs), where inv(16)(p13q22) is believed to occur, leading to leukemia development. The measured distances in HSCs were compared with mesenchymal stem cells, peripheral blood lymphocytes, and fibroblasts, as spatial genome organization is determined to be cell-type specific. Results indicate that CBFB and MYH11 are significantly closer in HSCs compared with all other cell types examined. Furthermore, the CBFB-MYH11 distance is significantly reduced compared with CBFB and a control locus in HSCs, although separation between CBFB and the control is ∼70% of that between CBFB and MYH11 on metaphase chromosomes. HSCs were also treated with fragile site-inducing chemicals because both the genes contain translocation breakpoints within these regions. However, treatment with fragile site-inducing chemicals did not significantly affect the interphase distance. Consistent with previous studies, our results suggest that gene proximity may play a role in the formation of cancer-causing rearrangements, providing insight into the mechanism of chromosomal abnormalities in human tumors.

Modification of cast aluminum-matrix composite materials by refractory nanoparticles

The effect of SiO2 and Al2O3 oxide ceramic nanoparticles on the solidification of model samples based on a commercial D16 alloy is studied. The composite samples are fabricated by reaction casting when titanium, nickel, and ceramic powders are mixed with an aluminum melt. The grain size in a matrix, the size and shape of Al3Ti intermetallic inclusions, and the interphase distances in eutectics are determined with optical and scanning electron microscopes. A certain modifying effect of oxide ceramic nanoparticles on the structure of model CMs during their in situ formation is detected, and the inoculation effect of SiO2 added to a melt on the reaction products is most pronounced.

Characteristics of Direct Lightning Strokes to Phase Conductors of UHV Transmission Lines

Since transmission towers are taller and interphase distances are longer for ultra-high voltage (UHV) transmission lines than for conventional transmission lines, it is important to know the features of direct lightning strokes to phase conductors. With this in mind, the features of direct lightning strokes to UHV transmission lines were observed and 81 datasets were obtained for seven years between 1998 and 2004. Of the 81 datasets, 79 recorded strokes from negative lightning, and the characteristic features of these direct lightning strokes were quantitatively evaluated by Electromagnetic Transients Program analysis of the current amplitude, front duration, and stroke duration. The frequency distribution of lightning strokes to each phase conductor was different from the estimated values obtained from conventional shielding models. Based on the cumulative frequency distribution of the current amplitude observed in this study, a method is proposed for calculating direct lightning stroke current as part of designing lightning protection

Genetic Control of Mitosis: Mutation ff3 Causes Premature Beginning of Telophase Chromatin Reorganization in Drosophila melanogaster

The effect of cell cycle mutation ff3 on chromosome segregation was studied on fixed cells of neural ganglia of Drosophila melanogasterlarvae. The cell distributions by diameter of interphase nuclei and by distance between sister chromatid sets were compared at anaphase and telophase. In the control wild-type strain Lausenne, the cell distribution by distance between sister chromatids in anaphase was similar to their distribution by nuclear size. The mean distance between segregating chromatids at anaphase (l av) coincided with the mean diameter of interphase nuclei (d av) and was 8.3 μm. Cells passed to telophase when chromatids were at least 10 μm apart. The mutant ff3 strain differed from the control strain Lausenne in cell distribution by interphase nuclear diameter and distance between sister chromatids in anaphase; the mean nuclear diameter and mean distance between segregating chromatids similarly increased to 9.3 μm. A specific feature of mitosis in mutant strain ff3 was a premature beginning of telophase chromatin reorganization. This caused the occurrence of cells with abnormally short (less then the interphase nuclear diameter) distance between sister chromatid sets in telophase but not in anaphase, as if these cells had passed from anaphase to telophase prematurely, during the chromatid movement toward poles in anaphase A.

Electromagnetic losses in a three-phase high temperature superconducting cable determined by calorimetric measurements

A 10 m long high temperature superconducting (HTS) cable conductor was placed in a plane three-phase arrangement. The test-bed enabled us to study the conductor losses for different separations between the phases. The superconductor was fixed symmetrically in the centre, whilst the two outer conventional phases (600 mm 2 Cu) could be moved in the plane. It was possible to vary the inter-phase distance (centre to centre distance) from 9 to 48 cm. The HTS cable conductor was placed in a stainless steel cryostat and cooled with flowing liquid nitrogen (LN2). The losses were determined using a calorimetric technique where the temperature increase in the flowing LN2 was measured with a set of thermo-couples. Results indicate that the total AC loss increases significantly when the separation between the conductors is reduced.

The effect of the interphase on crack-inclusion interactions

The problem of a radial or circumferential matrix crack interacting with a circular inclusion surrounded by an interphase region is investigated. The problem is formulated using Kolosov-Muskhelishvili complex potentials where the crack is modeled as a distribution of dislocations. The complex potentials for a dislocation interacting with a circular inclusion with an interphase are first rederived and then used in the crack formulation. The corresponding Cauchy singular integral equations are then solved using the Lobatto–Chebyshev quadrature technique. After comparing the current solution with previously published results, the influence of the interphase stiffness and thickness on a radial or circumferential matrix crack is studied for a glass fiber-epoxy composite. From this study it was found that compliant interphases increase the Mode I stress intensity factors for radial cracks while stiff interphases shield these cracks from the inclusion relative to the no-interphase cases. Additionally, the compliant interphases were found to be more affected by the thickness of the interphase. Results for the circumferential cracks were not as straightforward. Compliant interphases decreased the Mode II stress intensity factors but, depending on the interphase thickness and distance from the crack, could either shield or enhance the Mode I stress intensity factors. Stiff interphases increased the Mode II SIF but decreased the Mode I SIF as compared to the no-interphase cases.

Morphology of Ni-base superalloys via very small-angle neutron scattering technique

Very small-angle neutron scattering (VSANS) was used to develop a nondestructive inspecting technique for predicting the residual life time of turbine blades made from single crystal Ni-base superalloy. The VSANS curves, obtained from single crystalline CMSX-4 samples with the various degrees of damage, clearly show the first order peak of the lamellar structure created by a sequence of γ and γ' phases in this material. The peak shifts in the direction of lower scattering vector magnitudes when the creep damage increases, which reflects a corresponding increase of the period of the lamellar structure. According to the VSANS data, the interphase distance in the samples increases gradually (but does not grow rapidly) with increasing creep damage when the latter is &lt; 54% of the creep leading to rupture. Thus, the interphase distance is a sensitive parameter which can be used to describe the morphological changes in Ni-base superalloys related to creep damage. The results are consistent with those obtained from scanning electron microscopy.

Interphase fluorescence in situ hybridization mapping: a physical mapping strategy for plant species with large complex genomes.

The chromatin in interphase nuclei is much less condensed than are metaphase chromosomes, making the resolving power of fluorescence in situ hybridization (FISH) two orders of magnitude higher in interphase nuclei than on metaphase chromosomes. In mammalian species it has been demonstrated that within a certain range the interphase distance between two FISH sites can be used to estimate the linear DNA distance between the two probes. The interphase mapping strategy has never been applied in plant species, mainly because of the low sensitivity of the FISH technique on plant chromosomes. Using a CCD (charge-coupled device) camera system, we demonstrate that DNA probes in the 4 to 8 kb range can be detected on both metaphase and interphase chromosomes in maize. DNA probes pA1-Lc and pSh2.5.SstISalI, which contain the maize loci a1 and sh2, respectively, and are separated by 140 kb, completely overlapped on metaphase chromosomes. However, when the two probes were mapped in interphase nuclei, the FISH signals were well separated from each other in 86% of the FISH sites analyzed. The average interphase distance between the two probes was 0.50 micron. This result suggests that the resolving power of interphase FISH mapping in plant species can be as little as 100 kb. We also mapped the interphase locations of another pair of probes, ksu3/4 and ksu16, which span the Rp1 complex controlling rust resistance of maize. Probes ksu3/4 and ksu16 were mapped genetically approximately 4 cM apart and their FISH signals were also overlapped on metaphase chromosomes. These two probes were separated by an average of 2.32 microns in interphase nuclei. The possibility of estimating the linear DNA distance between ksu3/4 and ksu16 is discussed.

Evidence for the organization of chromatin in megabase pair-sized loops arranged along a random walk path in the human G0/G1 interphase nucleus.

We determined the folding of chromosomes in interphase nuclei by measuring the distance between points on the same chromosome. Over 25,000 measurements were made in G0/G1 nuclei between DNA sequences separated by 0.15-190 megabase pairs (Mbp) on three human chromosomes. The DNA sequences were specifically labeled by fluorescence in situ hybridization. The relationship between mean-square interphase distance and genomic separation has two linear phases, with a transition at approximately 2 Mbp. This biphasic relationship indicates the existence of two organizational levels at scales > 100 kbp. On one level, chromatin appears to be arranged in large loops several Mbp in size. Within each loop, chromatin is randomly folded. On the second level, specific loop-attachment sites are arranged to form a supple, backbonelike structure, which also shows characteristic random walk behavior. This random walk/giant loop model is the simplest model that fully describes the observed large-scale spatial relationships. Additional evidence for large loops comes from measurements among probes in Xq28, where interphase distance increases and then locally decreases with increasing genomic separation.

Treatment of cells with alkaline borate buffer extends the capability of interphase FISH mapping

Interphase fluorescence in situ hybridization (FISH) has been shown to be a means to map DNA sequences relative to each other in the 100 kb to 1–2 Mb genomic-separation range. At distances below 0.1 Mb, probe sites are infrequently resolved in interphase chromatin. In the 0.1- to 1-Mb range, interphase chromatin can be modeled as a freely flexible chain. The mean square interphase distance between two probes is proportional to the genomic separation between the probes on the linear DNA molecule. Above 1–2 Mb, the relationship between interphase distance and genomic separation changes abruptly and appears to level off. We have used alkaline-borate treatment to expand the capability of interphase FISH mapping. We show here that alkaline-borate treatment increases nuclear diameter, the interphase distance between probes on homologous chromosomes, and the distance between probes on the same chromosome. We also show that the mean square distance between hybridization sites in borate-treated nuclei is proportional to genomic separation up to 4 Mb. Thus, alkaline-borate treatment enhances the capability of interphase FISH mapping by increasing the absolute distance between probes and extending the range of the simple relationship between interphase distance and genomic separation.

Ordering of probes surrounding the Ewing's sarcoma breakpoint on chromosome 22 using fluorescent in situ hybridization to interphase nuclei.

Eight probes were localized by fluorescent in situ hybridization to the region surrounding the Ewing's sarcoma breakpoint on chromosome 22. Three of these were initially ordered by pair-wise hybridization to metaphase chromosomes with differential detection of the probes. These and the remaining probes were then ordered by hybridizing two or three probes simultaneously to interphase nuclei. In the two probe experiments and some of the three probe experiments, the order was derived by comparing mean interphase distances between signals from the probes. In the three probe experiments, either two probes were detected with one fluorochrome and the third with another or all three probes were individually distinguished by detecting one probe with fluorescein isothiocyanate (FITC), one with Texas Red, and one with both fluorochromes to give a mixed color. The order of the signals was then noted. Greater than 60 percent of configurations with a discrete order were shown or deduced to be correct. These approaches are assessed and we demonstrate a more obvious predominating order when all three probes are differentially detected. The order of the probes was deduced to be centromere: D22S271: D22S260: lambda S1: D22S262: cosK1831: Ewing's sarcoma breakpoint: cosLIF: D22S261: lambda S15: telomere.

Fine mapping of the human MHC class II region within chromosome band 6p21 and evaluation of probe ordering using interphase fluorescence in situ hybridization.

Eight previously well-characterized and mapped probes derived from the human major histocompatibility complex (MHC) class II region were used to investigate the advantages and limitations of fluorescence in situ hybridization (FISH) techniques for fine mapping. The class II region of the MHC was localized within subband 6p21.31 by in situ hybridization on metaphase chromosomes that were banded by immunofluorescence staining with an antibody against 5-bromodeoxyuridine (BrdU). Ordering of probes that were separated by up to 900 kb was achieved by simultaneous hybridization of two or three probes on interphase nuclei. Three-color FISH proved to be an excellent method for ordering of probes within distances of 200-1,000 kb. Under certain conditions, closer probes could be ordered by comparing measured distances between their hybridization signals in interphase nuclei. A linear correlation between measured interphase distances and kilobase distances was observed up to 500 kb. With increasing distances, the measurements become more inaccurate due to chromatin folding.

Fluorescence in situ hybridization establishes the order cen-DXS28(C7)-DXS67(B24)-DXS68(L1)-tel in human chromosome Xp21.3

We report here on the order of three DNA markers, C7, B24, and L1, based on the arrangement of their fluorescently labeled hybridization sites in interphase cell nuclei. The three markers map distal to the Duchenne muscular dystrophy (DMD), glycerol kinase deficiency (GKD), and adrenal hypoplasia (AHC) loci on human chromosome Xp21.3. Their order has been a matter of controversy. In interphase chromatin, B24 maps between C7 and L1. We estimate from interphase distance that C7 and L1 are 300–500 kb apart. When the three markers are hybridized to interphase cells of Nijmegenl, a patient with DMD, GKD, and AHC, only C7 appears to be deleted, rather than both C7 and L1, as had been reported elsewhere. C7 is also the only one of the three markers deleted in several other DMD patients studied by others. The deletion results indicate that C7 is the most proximal of the three markers and allow the trio of ordered probes to be oriented on the chromosome: cen-C7(DXS28)-B24(DXS67)-L1(DXS68)-tel.