Outermost Diameter Research Articles

A Break in the Size–Stellar Mass Relation: Evidence for Quenching and Feedback in Dwarf Galaxies

Mapping stars and gas in nearby galaxies is fundamental for understanding their growth and the impact of their environment. This issue is addressed by comparing the stellar “edges” of galaxies D stellar, defined as the outermost diameter where in situ star formation significantly drops, with the gaseous distribution parameterized by the neutral atomic hydrogen diameter measured at 1 M ⊙ pc−2, D HI. By sampling a broad H i mass range 105 M ⊙ < M HI < 1011 M ⊙, we find several dwarf galaxies with M HI < 109 M ⊙ from the field and Fornax Cluster that are distinguished by D stellar ≫ D HI. For the cluster dwarfs, the average H i surface density near D stellar is ∼0.3 M ⊙ pc−2, reflecting the impact of quenching and outside-in gas removal from ram pressure and tidal interactions. In comparison, D stellar/D HI ranges between 0.5 and 2 in dwarf field galaxies, consistent with the expectations from stellar feedback. Only more massive disk galaxies in the field can thus be characterized by the common assumption that D stellar ≲ D HI. We discover a break in the D stellar–M ⋆ relation at m break ∼ 4 × 108 M ⊙ that potentially differentiates the low-mass regime, where the influence of stellar feedback and environmental processes more prominently regulates the sizes of nearby galaxies. Our results highlight the importance of combining deep optical and H i imaging for understanding galaxy evolution.

Optimization of Sawtooth Electrode for Improving Collection Efficiency of Electrostatic Precipitator

This research used an electrostatic precipitator (ESP) with multiple sawtooth discharge electrode plates and one hollow cylindrical collecting electrode. The discharge electrode was a circular plate with sawtooth spikes. The collection efficiency was analyzed via simulations using three geometric parameters: the outermost diameter of the discharge electrode, the distance between the electrode plates, and the number of spikes. Among the cases considered for the discharge electrode geometry optimization using the Taguchi method, the parameter combination with the highest collection efficiency was selected. The simulation result was verified by building electrostatic precipitator geometry before and after its optimization and subsequently measuring its collection efficiencies. The collection efficiency of an ESP with the discharge electrode of the optimal geometry was higher by 15% than that of its reference geometry. It is expected that the collection efficiency of other types of ESP can be maximized using a similar discharge electrode geometry optimization.

Proposal of Design Method for Viscous Micropumps with a Rotating-Disk Using Theory and Simulation

The aim of the present study is to treat circular- and spiral-shaped viscous micropumps unitarily and provide guidelines for determining the appropriate micropump for performance requirements. Three-dimensional theoretical equations applicable to circular- and spiral-shaped micropumps were derived. Numerical simulations were also performed, and the results were compared with the theoretical results. The results were qualitatively consistent. By comparing the performances of the two micropumps, the spiral- and the circular-shaped micropumps are suitable in the ratio of outermost diameter to channel width c<SUP>*</SUP> < 0.2, and c<SUP>*</SUP> > 0.2, respectively. The theoretical performance for rotating disk-type micropumps was expressed in a unified manner. Furthermore, the design guideline was provided based on the theoretical method.

Critical current density for layer-by-layer breakdown of a multiwall carbon nanotube

Electric-current-induced structural changes in a suspended multiwall carbon nanotube (MWCNT) were observed through in situ transmission electron microscopy. The bias voltage and electric current were measured simultaneously as the MWCNT was imaged. The passage of excessive current led to breakdown of the surface of the MWCNT and to subsequent layer-by-layer removal of the broken outermost shell via sublimation of carbon atoms. The surface breakdown of the MWCNT was accompanied by a discrete decrease in the current. Under the assumption that the current passes solely through the outermost shell of the MWCNT, we found that the critical current densities at which the breakdown in the renewed outermost shell occurred after the removal of the broken outermost shell were limited to a remarkably narrow range of (2.4 ± 0.2) × 109 A/cm2, irrespective of the outermost diameter of the MWCNT. The present results provide invaluable information about electron transport phenomena in MWCNTs and about the durability of CNT nanocircuits.

Preliminary Design of DC Magnet for Super-X Test Facility

The engineering design of the China Fusion Engineering Test Reactor (CFETR) has been completed in 2020. A largescale R&D project for CFETR named the comprehensive research facility for fusion technology (CRAFT) was initiated in Sep. 2019. As a sub-task of the CRAFT, a superconducting experiment testing platform (Super-X for short) is planned to be constructed for evaluating the future superconducting parts performance. Its main technical parameter includes: the background field of 15 T, the dimensions of testing space of 100 × 160 × 550 mm, the field homogeneity of testing space ≥ 95%, and the maximum testing current of 100 kA. For now, the preliminary design for Super-X has been accomplished. The DC magnet provides the background magnetic field for Super-X. It is a kind of split coil that includes two symmetrical coils assemblies. The innermost diameter is about 644 mm, the outermost diameter is 2874 mm. Each coil assembly is composed of three concentric Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn coils. The peak field is 15.7 T and the field homogeneity reach to 98.2%. The high field coil (HFC) and medium field coil (MFC) is typically dominated by high-J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn cable-in-conduit conductor (CICC), and the low field coil (LFC) by ITER grade Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn CICC. This paper presents the preliminary design of the background DC magnet system (BM).

Whole-surface emission concentric shells for large light bulb using total internal reflection

Surface emission concentric shells that can emit both light rays and a large amount of heat from the whole outer surface are proposed here for a large globe light-emitting diode (LED) bulb. The concentric shells are composed of an outer total internal reflection (TIR) shell and an inner metallic shell adjacent to the outer shell. The TIR shell can guide light rays emitted from LEDs owing to the TIR and emits illuminating light from the outer surface. Assuming that the thickness of the TIR shell is sufficiently small, the TIR shell can also emit heat of the inner shell to the outside. It is theoretically predicted based on the heat transfer theory that the larger the concentric shells are, the larger the amount of heat that can be emitted to the outside. A large globe LED bulb prototype having the concentric shells with an outermost diameter of about 95 mm is therefore designed and fabricated, with which it is shown that an illuminating light flux of about 1064 lumens and heat of about 12.2 W can both be emitted to the outside. The prototype also shows to have a large hollow structure in which several kinds of devices can be accommodated.

Crashworthiness analysis of bionic thin-walled tubes inspired by the evolution laws of plant stems

Recently, bionic thin-walled structures have attracted widespread attention in automotive safety design because of their excellent crashworthiness behavior and weight efficiency. In this paper, inspired by the evolution laws and microstructure of plant stems, a group of bionic tubes with m parts and n layers (PmLnBTs) are proposed and investigated by theoretical prediction and numerical analysis. Theoretical models of PmLnBTs are developed to predict the specific energy absorption. Finite element model is conducted with LS-DYNA and validated by a quasi-static axial crushing experiment. The accuracy of the theoretical model is verified by numerical analysis, and the maximum relative error is less than 7%. Furthermore, parametric studies are conducted to investigate the effects of geometric parameters on the energy absorption capability of PmLnBTs. The results indicate that the PmLnBTs exhibit superior crashworthiness performance compared to traditional bi-tubular circle tubes. Moreover, when designing such a bionic energy absorber, it can effectively improve the crashworthiness performance by appropriately increasing the number of layers, reducing the outermost circle diameter or avoiding innermost circle diameter value too large or too small. The findings of this paper provide a guidance for the design of energy absorber with excellent energy absorption performance.

Determination of nonlinear refractive index of paprika oil and pepper oil under cw visible laser illumination

We report the observation of multiple diffraction rings patterns in paprika and pepper oils using continuous wave laser beams .The patterns occur at relatively low intensities . The number of rings together with outermost ring diameter of each pattern increases monotonically with increasing input power . The total changes in refractive index , ?n ,and nonlinear refractive index,n2 ,are determined using the number of rings observed in both samples and 473 nm and 532 nm laser beams . We obtained good values of ?n = 0.01 and n2 = 10-6 cm2/w . These large values are attributed to thermal effects .

A study on process design of plate cold forging for machinability improvement of piston under drive brake

Reduction of energy in manufacturing industries is a current issue to keep the earth green. This energy saving yields the cost reduction in automotive industries. Many automotive part companies try to improve their manufacturing process to save the manufacturing energy. Specially, many attempts on changing the hot forging process into the cold forging process of plate forging have been tackled in the piston under drive brake used in an automotive transmission module. The turning process after hot forging changed to turning after plate cold forging for the energy and cost reduction. But two extrusion shapes in an outermost diameter of part let fall tool life by interrupted cut in turning. Therefore, it needs thickness reduction of two extrusion areas in the outermost diameter. This study suggests an effective way to reduce the thickness of interrupted cut in forging stage.

Low-loss shielded through-silicon vias filled with multi-walled carbon nanotube bundle

In this paper, the multi-walled carbon nanotube bundle (MWCNTB) based shielded through-silicon via (S-TSV) is proposed and the compact expression for the equivalent conductivity of MWCNTB (σMWCNTB) is deduced to calculate the resistance of MWCNTB based S-TSV (MS-TSV). Then, the electrical characteristics including the S parameters, attenuation constant and time delay are investigated. The results indicate that |S21| of MS-TSV increases with the increase of the outermost diameter of MWCNT and decrease of the thickness of the shielding layer. Compared with the copper filled S-TSV (CuS-TSV), the MS-TSV has a larger |S21|, smaller attenuation and shorter time delay. Finally, the impact of the geometrical parameters on the conductivity of MS-TSV is analyzed. Also, the minimum packing density of MWCNTB satisfying σMWCNTB≥σCu has been deduced. The results show that the outermost diameter of MWCNT has the most significant impact on the conductivity of MS-TSV, and thicker MWCNT is helpful to increase the conductivity of MS-TSV, decrease the packing density of MWCNTB and reduce manufacturing difficulty.

Three-dimensional structure of a protozoal double-stranded RNA virus that infects the enteric pathogen Giardia lamblia.

Giardia lamblia virus (GLV) is a small, nonenveloped, nonsegmented double-stranded RNA (dsRNA) virus infecting Giardia lamblia, the most common protozoan pathogen of the human intestine and a major agent of waterborne diarrheal disease worldwide. GLV (genus Giardiavirus) is a member of family Totiviridae, along with several other groups of protozoal or fungal viruses, including Leishmania RNA viruses and Trichomonas vaginalis viruses. Interestingly, GLV is more closely related than other Totiviridae members to a group of recently discovered metazoan viruses that includes penaeid shrimp infectious myonecrosis virus (IMNV). Moreover, GLV is the only known protozoal dsRNA virus that can transmit efficiently by extracellular means, also like IMNV. In this study, we used transmission electron cryomicroscopy and icosahedral image reconstruction to examine the GLV virion at an estimated resolution of 6.0 Å. Its outermost diameter is 485 Å, making it the largest totivirus capsid analyzed to date. Structural comparisons of GLV and other totiviruses highlighted a related "T=2" capsid organization and a conserved helix-rich fold in the capsid subunits. In agreement with its unique capacity as a protozoal dsRNA virus to survive and transmit through extracellular environments, GLV was found to be more thermoresistant than Trichomonas vaginalis virus 1, but no specific protein machinery to mediate cell entry, such as the fiber complexes in IMNV, could be localized. These and other structural and biochemical findings provide a basis for future work to dissect the cell entry mechanism of GLV into a "primitive" (early-branching) eukaryotic host and an important enteric pathogen of humans. Numerous pathogenic bacteria, including Corynebacterium diphtheriae, Salmonella enterica, and Vibrio cholerae, are infected with lysogenic bacteriophages that contribute significantly to bacterial virulence. In line with this phenomenon, several pathogenic protozoa, including Giardia lamblia, Leishmania species, and Trichomonas vaginalis are persistently infected with dsRNA viruses, and growing evidence indicates that at least some of these protozoal viruses can likewise enhance the pathogenicity of their hosts. Understanding of these protozoal viruses, however, lags far behind that of many bacteriophages. Here, we investigated the dsRNA virus that infects the widespread enteric parasite Giardia lamblia. Using electron cryomicroscopy and icosahedral image reconstruction, we determined the virion structure of Giardia lamblia virus, obtaining new information relating to its assembly, stability, functions in cell entry and transcription, and similarities and differences with other dsRNA viruses. The results of our study set the stage for further mechanistic work on the roles of these viruses in protozoal virulence.

Computed tomography-based morphometric analysis of cervical pedicles in Indian population

Cervical transpedicular screw fixation is safe and is probably going to be the gold standard for cervical spine fixation. However, cervical transpedicular screw use in the Asian population can be limited as the transverse diameter in this group of patients may not be adequate to accommodate the 3.5-mm pedicular screw thus injuring the vital structures located in the close proximity of the pedicles. Thus lateral mass fixation remains the mainstay of treatment. The present study evaluated the transverse cervical pedicle diameter of C2-C7 vertebrae in a pilot study in 27 Indian subjects using computed tomography (CT) imaging and evaluated the feasibility of transpedicular screw fixation in them. To evaluate the feasibility of transpedicular screw fixation in the Indian population. The cervical pedicle diameter size differs between the Asian and non-Asian population. The authors studied the transverse pedicle diameter of the C2-C7 of the cervical spine in the Indian population using CT measurements. This cross-sectional study was carried out at a tertiary care centre for a period of four months from October 2010 to December 2010. Measurements of cervical pedicles in the subjects were performed on the CT workstation from the CT images taken at 2.5-mm interval. The transverse pedicle diameter was defined as the outermost diameter of the pedicle, taken perpendicular to the axis of the pedicle at the narrowest point and measured in millimeters±0.1 mm. Descriptive statistics was used to represent percentage of transverse diameter of cervical pedicles less than 5 mm in male and female subjects at C2-C7 levels. Since there is no previous study done in India, we initiated the study with sample size of 27 as a pilot study. The statistical analysis was performed using SPSS software. The mean transverse diameters of the cervical pedicles of C2, C3, C4, C5, C6 and C7 in males were 5.3, 5.3, 5.3, 5.6, 5.6 and 6.1 mm respectively and ranged between 5.3 to 6.1 mm. The mean transverse diameters of the cervical pedicles of C2, C3, C4, C5, C6 and C7 in females were 5.1, 4.6, 4.7, 4.7, 5.3 and 5.6 mm respectively and ranged between 4.6 to 5.6 mm. Between 2.1% and 55.7% of pedicles in our male population and between 5.5% and 74.3% pedicles in our female population was smaller than 5.0 mm in transverse diameter and thus cannot have fixation with a 3.5 mm screw using this technique. We found that the transverse pedicle diameter of cervical pedicles in the Indian subjects is smaller compared to the Western population. Although transpedicular screw fixation has stronger pullout strength compared to lateral mass fixation, its use must be considered carefully and individually. Preoperative CT evaluation is a must before transpedicular fixation in the cervical spine, especially in the Indian female population. As an option 2.7-mm screws can be devised for the Indian population giving a wider safety margin.

Characterization of zone plate properties using monochromatic synchrotron radiation in the 2 to 20 nm wavelength range

A zone plate composed of Mo zones having 4 mm outermost zone diameter, 100 nm outermost zone width, and supported on a silicon nitride membrane was characterized using monochromatic synchrotron radiation in the 2 to 20 nm wavelength range. The zero and first order efficiencies were measured and compared to ab initio calculations that account for the optical properties of the materials, the width and shape of the zones, and multiple-layer thin-film effects. It is shown that the thicknesses of the Mo zones and the membrane and the ratio of the zone width to zone period can be independently determined from the measured diffraction efficiencies in the zero and first orders and that the computational code can be used to reliably design zone plates that are optimized for applications such as solar irradiance monitors in the extreme ultraviolet region.

Three-primary-color upconversion luminescence in rare earth-doped β-NaLuF4 microtubes

Lanthanide ions-doped NaLuF4 hexagonal-prismatic microtubes have been successfully synthesized via a facile hydrothermal approach for the first time. The as-grown microtubes are determined to be pure hexagonal (β-) NaLuF4 phase with an outermost diameter of about 3 μm and a length of approximately 40 μm. The Yb3+/Er3+(Tm3+)-codoped NaLuF4 microtubes emit bright three-primary-color (red, green, and blue) light under 980 nm laser diode excitation undergoing an upconversion. Mechanisms for the excitation and emission were analyzed based on the emission spectra, the plot of luminescence intensity to pump power and a simplified energy level diagram.

Multiple emulsions: Small 18/2009

The cover picture shows an optical microscopy image of monodisperse W/O/W/O/W/O quintuple emulsions formed using a glass-coated poly(dimethylsiloxane) device. The device consists of five sequential drop makers functionalized to have alternating hydrophilic/hydrophobic wettability. The outermost drop diameter is about 120 micrometers. For more information, please read the Communication “High-Order Multiple Emulsions Formed in Poly(dimethylsiloxane) Microfluidics” by A. R. Abate and D. A. Weitz, beginning on page 2030.

Examining the effects of wall numbers on buckling behavior and mechanical properties of multiwalled carbon nanotubes via molecular dynamics simulations

Molecular dynamics simulations are performed on multiwalled carbon nanotubes (MWCNTs) under axial compression to investigate the effects of the number of walls and their van der Waals (vdW) interaction on the buckling behaviors and mechanical properties (Young’s modulus and Poisson’s ratio). The Brenner second-generation reactive empirical bond order and Lennard–Jones 12-6 potential have been adopted to describe the short-range bonding and long-range vdW atomic interaction within the carbon nanotubes, respectively. In the presence of vdW interaction, the buckling strain and Young’s modulus of MWCNTs increase as the number of tubes is increased while keeping the outermost tube diameter constant, whereas Poisson’s ratio was observed to decrease. On the other hand, when the MWCNTs are formed by progressively adding outer tubes while keeping the innermost tube diameter constant, Young’s modulus and buckling strain were observed to decrease, whereas Poisson’s ratio increases. The buckling load increases with increasing the number of walls due to the larger cross-sectional areas. Individual tubes of MWCNTs with a relatively large difference between the diameters of the inner and outer tubes buckle one at a time as opposed to simultaneously for MWCNTs with a relatively small difference in diameters.

Multiwalled carbon nanotubes mass-produced by dc arc discharge in He–H2 gas mixture

Uniform cathode deposits (longer than 15 mm), containing multiwalled carbon nanotubes (MWNTs) inside, were produced by dc arc discharge evaporation with a computer-controlled feeder of a pure-carbon electrode without a metal catalyst in a He–H2 gas mixture. The purification of MWNTs was carried out to remove amorphous carbon and carbon nanoparticles. High-resolution transmission electron microscopy observations and Raman scattering studies show that the MWNTs possess a high crystallinity and a mean outermost diameter of ∼ ∼10 nm. It has been confirmed that the current density in the electron field emission from a purified MWNT mat can reach 77.92 mA/cm2, indicating that the purified MWNTs are a promising candidate electron source in a super high-luminance light-source tube or a miniature X-ray source.

Characterization of thin multi-walled carbon nanotubes synthesized by catalytic chemical vapor deposition

Thin multi-walled carbon nanotubes (t-MWCNTs) synthesized by catalytic chemical vapor deposition were characterized by transmission electron microscopy (TEM), Raman spectroscopy, and gas adsorption. TEM observations showed that the innermost diameter ranges from less than 1 to 5 nm and the outermost diameter ranges from 4 to 12 nm, which are much smaller than conventional thick MWCNTs. We observed clear radial breathing modes in Raman spectra, which are attributed to the existence of inner nanotubes in small diameters less than 3 nm. We also performed N 2 adsorption at 77 K after the tip opening of t-MWCNTs by nitric acid in order to analyze the tube inner diameters. The pores with sizes less than 4 nm corresponding to the inner empty space of t-MWCNTs were largely developed, in good agreement with TEM and Raman observations.

A hard X-ray telescope with multilayered supermirrors for balloon observations of cosmic X-ray sources

We have been developing a hard X-ray telescope utilizing multilayer supermirrors. The international focusing optics collaboration for μ-Crab sensitivity (InFOCμS) project is for balloon observations of cosmic hard X-ray sky with this new type of telescope. For the first flight scheduled in the next summer, we are preparing one full telescope with outermost diameter of 40 cm, focal length of 8 m, and energy band witgh of 20 – 40 keV as a first step. At the focal plane a CdZnTe imaging detector will be prepared. In this paper, the science objectives of this project, current status of the development of gondola, X-ray telescope and hard x-ray detector, and expected performance are described.

Column buckling of multiwalled carbon nanotubes with interlayer radial displacements

An elastic model is presented for column buckling of a multiwalled carbon nanotube embedded within an elastic medium. The emphasis is placed on the role of interlayer radial displacements between adjacent nanotubes. In contrast to an existing model which treats the entire multiwalled nanotube as a single column, the present model treats each of the nested tubes as an individual column interacting with adjacent nanotubes through the intertube van der Waals forces. Based on this model, a condition is derived in terms of the parameters describing the van der Waals interaction, under which the effect of the noncoincidence of all deflected column axes is so small that it does not virtually affect the critical axial strain. In particular, this condition is met for carbon multiwalled nanotubes provided that the half-wavelength of the buckling mode is much larger than the outermost diameter. In this case, the critical axial strain can be predicted correctly by the existing single-column model. On the other hand, the existing model could overestimate the critical axial strain when the half-wavelength of the buckling mode is close to or smaller than the outermost radius.