Smooth Convex Surface Research Articles

A New Concept of the Surface Wave of the Interference Type for the Smooth Convex Surfaces Embedded in ℝ3

A New Concept of the Surface Wave of the Interference Type for the Smooth Convex Surfaces Embedded in ℝ3

Molecular Identification and Antimicrobial Potency of Probiotic Lactic Acid Bacteria Pado (Fish Fermentation) Nagari Balingka IV Koto District-West Sumatra as a Functional Food

Pado, indigenous cuisine from the region of West Sumatera, is a mixture of fish with the meat seed of Simuang (Pangium edule Reinw) and grated coconut fermented for 4-8 days. Pado is thought to contain lactic acid bacteria (LAB) activity used as a probiotic-producing functional food which is good nutritional value. Based on it, Pado had the potency to improve the economy which had a good impact on regional development. This aims to decide the molecular identifications and antimicrobial activity of LAB as probiotics contain in Pado that are useful as functional foods. The sample used as material for this research is Pado from Nagari Balingka IV Koto District in Agam Regency-West Sumatera. The research methods are bacterial isolation from Pado, determinate LAB using laboratory analysis, and LAB identification using the 16S rRNA method. The result of Gram staining showed Gram-positive that the purple rod-shaped. The other characteristics of Pado isolate were homofermentative, catalase-negative, resistant to acidic pH, and bile salt. The colony of Pado LAB has a white-beige smooth-convex surface. Pado Nagari Balingka IV Koto is a functional food that contains the probiotic Lactobacillus plantarum strain SRCM 102737 and it had antimicrobial activity against pathogen bacteria.

Sphere Last‐Passage Algorithm for Charge Density on a Smooth (Convex) Conducting Surface

AbstractIn a series of papers, the authors have been developing last‐passage algorithms such as last‐passage algorithm and off‐centered last‐passage algorithm on a flat conducting surface, quadrupole last‐passage algorithm on an L‐shaped conducting surface, and last‐passage algorithm on a spherical conducting surface, held at (non)constant potentials. All the previous last‐passage algorithms can compute charge density at a specific point on a flat or spherical conducting surface only. In this paper, the last‐passage algorithms on any smooth (convex) surface for charge density at a specific point are further developed where a tangent plane can be constructed and a sphere can be put. The algorithm for charge density on a sphere, on a circular plate, and on the unit cube held at unit potential is demonstrated. The results show excellent agreements with theoretical or other simulation ones.

Bacillus suaedae sp. nov., isolated from the stem of Suaeda aralocaspica in north-west China

A bacterial strain, designated YZJH907-2T, was isolated from the stem of Suaeda aralocaspica, collected from the southern edge of the Gurbantunggut desert, Xinjiang, PR China. Cells of strain YZJH907-2T were Gram-stain-positive, aerobic and rod-shaped. They formed white or colourless circular colonies with smooth convex surfaces. Strain YZJH907-2T grew at 4-50 °C (optimum, 28-30 °C), pH 7.0-10.0 (optimum, pH 8.0-9.0) and with 0-10 % (w/v) NaCl (optimum, 3-7 %). The genomic DNA G+C content of strain YZJH907-2T was 38.1 mol%. Phylogenetic analysis based on 16S rRNA gene sequence similarity showed that the strain was most closely related to Bacillus alcalophilus DSM 485T (97.37 %), Bacillus kiskunsagensis B16-24T (96.87 %) and Bacillus bogoriensis LBB3T (96.71 %). Average nucleotide identity values between YZJH907-2T and B. alcalophilus DSM 485Tand B. bogoriensis LBB3T were 69.2 and 69.0 %, respectively. Digital DNA-DNA hybridization values of YZJH907-2T with B. alcalophilus DSM 485T and B. bogoriensis LBB3T were 19.6 and 20.4 %, respectively. The cell wall of strain YZJH907-2T contained meso-diaminopimelic acid, and the major and secondary isoprenoid quinones were MK-7 and MK-5, respectively. Results of fatty acids showed that anteiso-C15 : 0, iso-C15 : 0 and C16 : 0 were the predominant cellular fatty acids. Two-dimensional thin-layer chromatography analysis indicated that the polar lipids included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, three unidentified phospholipids and two unidentified glycolipids. Based on the genomic, phylogenetic and phenotypic analyses, strain YZJH907-2T represented a novel species of the genus Bacillus, and thus the name Bacillus suaedae sp. nov. is proposed. The type strain is YZJH907-2T (=CGMCC 1.18763T=KCTC 43335T).

Obstacle-induced giant jammed aggregation of active semiflexible filaments.

Filaments driven by bound motor proteins and chains of self-propelled colloidal particles are a typical example of active polymers (APs). Due to deformability, APs exhibit very rich dynamic behaviors and collective assembling structures. Here, we are concerned with a basic question: how APs behave near a single obstacle? We find that, in the presence of a big single obstacle, the assembly of APs becomes a two-state system, i.e. APs either gather nearly completely together into a giant jammed aggregate (GJA) on the surface of the obstacle or distribute freely in space. No partial aggregation is observed. Such a complete aggregation/collection is unexpected since it happens on a smooth convex surface instead of, e.g., a concave wedge. We find that the formation of a GJA experiences a process of nucleation and the curves of the transition between the GJA and the non-aggregate state form hysteresis-like loops. Statistical analysis of massive data on the growing time, chirality and angular velocity of both the GJAs and the corresponding nuclei shows the strong random nature of the phenomenon. Our results provide new insights into the behavior of APs in contact with porous media and also a reference for the design and application of polymeric active materials.

Synthesis of silica Janus nanosheets and their application to the improvement of interfacial interaction in wood polymer composites

The incompatibility between wood components and polymers negatively affects the physical and mechanical properties of wood polymer composites, which is still an obstacle to fabricating wood polymer composites with desirable performance. Inspired by the good compatibilization of Janus structure, silica Janus nanosheets were synthesized by sol–gel process and used to improve the interfacial interaction of methyl methacrylate (MMA)-impregnated wood in the present study. Results showed that the Janus nanosheets with smooth convex surfaces and rough concave surfaces were successfully synthesized. The thickness of Janus nanosheets was about 30 nm, and the length could be tuned by the time of the ultrasonication. With the addition of 0.5% nanosheets, the interface gaps between the polymer and wood cell wall were remarkably decreased compared to the MMA treated wood samples, indicating the efficient interfacial interaction due to Janus nanosheets. This improved interfacial interaction was also confirmed by the changes of the pore structure of MMA/Janus nanosheets-treated wood samples. The ASE of MMA/Janus sheets-treated wood was improved by 40% compared to MMA-treated wood samples. Compared to untreated wood samples, the water uptake of MMA/Janus sheets-treated wood was reduced by 61%, while the modulus of rupture and modulus of elasticity were improved by 31% and 45%, respectively, which were higher than MMA-treated wood. Moreover, the incorporation of silica nanosheets also improve the thermal stability of the MMA treated wood sample. This preliminary research will provide a new approach for enhancing the interfacial properties of wood polymer composites.

Local heat transfer characteristics of synthetic air jet impinging on a smooth convex surface

The local heat transfer characteristic of synthetic air jet impinging on convex surface is studied experimentally. The heat flux on the convex surface is maintained constant. The experiment is carried out for different actuator frequency (f = 100 Hz–300 Hz), jet to plate distance (z/d = 1 to 8) keeping the orifice diameter constant. The local heat transfer characteristic of synthetic air jet on the convex surface is obtained by IR thermal imager using thin foil technique. Local heat transfer characteristics is studied in terms of local Nusselt number along the axial (x/d at r = 0) and radial direction (r/d at x = 0) of convex surface. The obtained result shows that the local heat transfer is strongly influenced by actuator frequency and jet to plate distance. The actuator frequency (f = 200 Hz) and lower jet to plate distance (z/d = 2) is observed effective at all jet to plate distance and actuator frequency. The correlation of maximum local Nusselt number in terms of Reynolds number is obtained with the maximum deviation of 18%. The maximum uncertainty in measurement of average Nusselt number is observed less than ±6%.

Приближенные асимптотические выражения для электромагнитного поля и взаимной проводимости щелей в проводящей выпуклой поверхности вращения в виде рядов по азимутальным гармоникам

In this paper, we obtain approximate asymptotic expressions for the electromagnetic field and the self and mutual admittances of "single-mode" slots in a smooth convex surface of rotation of large sizes in the form of a series of azimuthal harmonics. The coefficients of the series are expressed as integrals over the wave spectrum and can be calculated numerically or as a sum series of deductions (for mutual admittances). The expressions for the coefficients are uniformly valid in the boundary surface layer, except for the vicinity of the poles of the surface of rotation, and do not have discontinuities on the caustics of the surface rays. The resulting expressions can be directly used to calculate the fields and the self and mutual admittances of annular slots. In contrast to the eigenfunction method, asymptotic expressions allow us to cover the case of an arbitrary-shaped surface and avoid summing slowly converging double series. A comparison of the results of calculating the admittances of annular slots in a conducting spherical surface obtained by the proposed method and the method of eigenfunctions was executed, and their good agreement shown even for a small radius of the sphere equal to 3λ.

Spatial Non-Stationary Contact Problem for a Cylindrical Shell And Absolutely Rigid Body

A spatial non-stationary contact problem with moving boundaries of the interaction region for a thin elastic cylindrical shell and an absolutely solid impactor bounded by a smooth convex surface is considered. A closed mathematical formulation is given and a system of resolving equations is constructed. The latter is based on the spatio-temporal integral equation resulting from the principle of superposition and contact conditions. The core of this equation is the influence function for the cylindrical shell. To a closed system of resolving equations, it is supplemented by a kinematic relation for determining the moving boundary of the contact region and the equation of motion of the impactor as an absolutely rigid body. An algorithm for solving the spatial non-stationary contact problem for an infinitely long cylindrical shell and absolutely solid impactor in the case of a normal impact on the side surface of the shell is constructed and implemented. Examples of calculations are given.

Bacillus miscanthi sp. nov., a alkaliphilic bacterium from the rhizosphere of Miscanthus sacchariflorus.

A novel bacterial strain, designated AK13T (=KACC 21401T=DSM 109981T), was isolated from the rhizosphere of Miscanthus sacchariflorus. Strain AK13T was found to be an aerobic, Gram-stain-positive, endospore-forming and rod-shaped bacterium. It formed yellow circular colonies with smooth convex surfaces. The genomic DNA G+C content of strain AK13T was estimated to be 40 mol%. Phylogenetic analysis based on 16S rRNA gene sequence similarity showed that this strain was most closely related to Bacillus lehensis MLB2T (99.4 %), Bacillus oshimensis K11T (98.8 %) and Bacillus patagoniensis PAT 05T (96.6 %). The average nucleotide identity values between strain AK13T and B. lehensis MLB2T, B. oshimensis K11T and B. patagoniensis PAT 05T were 90.93, 91.05 and 71.87 %, respectively, with the digital DNA-DNA hybridization values of 42.7, 42.6 and 18.8 %, respectively. Cells grew at 5-40 °C (optimum, 28-35 °C), pH 6.5-13 (optimum, pH 8-9) and in the presence of 0-13.0 % (w/v) NaCl (optimum, 1 %). The cell wall of strain AK13T contained meso-diaminopimelic acid, and the major isoprenoid quinone was MK-7. Results of fatty acid methyl ester analysis revealed that iso-C15 : 0 was the predominant cellular fatty acid. Two-dimensional thin-layer chromatography analysis indicated that the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and glycolipid. The genotypic and phenotypic characteristics suggested that strain AK13T represented a novel species of the genus Bacillus, and thus the name Bacillus miscanthi sp. nov. is proposed.

Aspergillus takadae, a novel heterothallic species of Aspergillus section Fumigati isolated from soil in China

Abstract Aspergillus takadae is characterized by its heterothallic reproduction, pale yellow cleistothecia, broadly lenticular ascospores with two short equatorial crests and smooth convex surfaces, and broadly ellipsoidal to ovate conidia with a smooth wall. The validation of these novel species is supported further by the analyses of the β-tubulin, calmodulin, actin, and RPB2 sequences. In addition, the phylogenetic tree and DDBJ accession numbers of all the species of Aspergillus section Fumigati are presented. We report on the crossing of A. takadae species and the result of crossing A. takadae with a closely related species, A. spathulatus.

Long Geodesics on Convex Surfaces

We review the theory of intrinsic geometry of convex surfaces in the Euclidean space and prove the following theorem: if the surface of a convex body K contains arbitrary long closed simple geodesics, then K is an isosceles tetrahedron.

Experimental evidence suggests that specular reflectance and glossy appearance help amplify warning signals

Specular reflection appears as a bright spot or highlight on any smooth glossy convex surface and is caused by a near mirror-like reflectance off the surface. Convex shapes always provide the ideal geometry for highlights, areas of very strong reflectance, regardless of the orientation of the surface or position of the receiver. Despite highlights and glossy appearance being common in chemically defended insects, their potential signalling function is unknown. We tested the role of highlights in warning colouration of a chemically defended, alpine leaf beetle, Oreina cacaliae. We reduced the beetles’ glossiness, hence their highlights, by applying a clear matt finish varnish on their elytra. We used blue tits as predators to examine whether the manipulation affected their initial latency to attack, avoidance learning and generalization of warning colouration. The birds learned to avoid both dull and glossy beetles but they initially avoided glossy prey more than dull prey. Interestingly, avoidance learning was generalized asymmetrically: birds that initially learned to avoid dull beetles avoided glossy beetles equally strongly, but not vice versa. We conclude that specular reflectance and glossiness can amplify the warning signal of O. cacaliae, augmenting avoidance learning, even if it is not critical for it.

Bacterial resistance of self-assembled surfaces using PPOm-b-PSBMAn zwitterionic copolymer – Concomitant effects of surface topography and surface chemistry on attachment of live bacteria

Three well-defined diblock copolymers made of poly(sulfobetaine methacrylate) (poly(SBMA)) and poly(propylene oxide) (PPO) groups were synthesized by atom transfer radical polymerization (ATRP) method. They were physically adsorbed onto three types of surfaces having different topography, including smooth flat surface, convex surface, and indented surface. Chemical state of surfaces was characterized by XPS while the various topographies were examined by SEM and AFM. Hydrophilicity of surfaces was dependent on both the surface chemistry and the surface topography, suggesting that orientation of copolymer brushes can be tuned in the design of surfaces aimed at resisting bacterial attachment. Escherichia coli, Staphylococcus epidermidis, Streptococcus mutans and Escherichia coli with green fluorescent protein (E. coli GFP) were used in bacterial tests to assess the resistance to bacterial attachment of poly(SBMA)-covered surfaces. Results highlighted a drastic improvement of resistance to bacterial adhesion with the increasing of poly(SBMA) to PPO ratio, as well as an important effect of surface topography. The chemical effect was directly related to the length of the hydrophilic moieties. When longer, more water could be entrapped, leading to improved anti-bacterial properties. The physical effect impacted on the orientation of the copolymer brushes, as well as on the surface contact area available. Convex surfaces as well as indented surfaces wafer presented the best resistance to bacterial adhesion. Indeed, bacterial attachment was more importantly reduced on these surfaces compared with smooth surfaces. It was explained by the non-orthogonal orientation of copolymer brushes, resulting in a more efficient surface coverage of zwitterionic molecules. This work suggests that not only the control of surface chemistry is essential in the preparation of surfaces resisting bacterial attachment, but also the control of surface topography and orientation of antifouling moieties.

Approximation by homogeneous polynomials

A new, elementary proof is given for the fact that on a centrally symmetric convex curve on the plane every continuous even function can be uniformly approximated by homogeneous polynomials. The theorem has been proven before by Benko and Kroó, and independently by Varjú using the theory of weighted potentials. In higher dimension the new method recaptures a theorem of Kroó and Szabados, which is the strongest result for homogeneous polynomial approximation on smooth convex surfaces.

Modified Phase-Extracted Basis Functions for Efficient Analysis of Scattering From Electrically Large Targets

In this paper, phase-extracted (MPE) basis functions with both the traveling wave terms and the standing wave terms have been proposed to analyze the scattering from the electrically large targets. This kind of basis functions, called modified phase-extracted (MPE) basis function, can be defined on the relatively large patches and constructed with the higher order hierarchical vector basis functions. The constructing idea of the MPE basis function is first introduced. Then, their characteristics were compared with the relevant basis functions. It has been demonstrated that the MPE basis function is suitable for the scattering analysis of the perfect electric conductors (PECs) with smooth convex surfaces as well as the concave structures, such as the electrically large cavities. The numerical solutions to the electromagnetic scattering from both the convex targets and the cavity-like targets with strong mutual couplings have been given to show the capability of the MPE basis functions in the description of the complex distribution of the induced current on the PEC surfaces. Some numerical examples have been given to demonstrate the validation of this kind of basis functions.

Infinitesimal rigidity of smooth convex surfaces through the second derivative of the Hilbert–Einstein functional

Infinitesimal rigidity of smooth convex surfaces through the second derivative of the Hilbert–Einstein functional

TD-UTD Solutions for the Transient Radiation and Surface Fields of Pulsed Antennas Placed on PEC Smooth Convex Surfaces

A time-domain formulation of the uniform geometrical theory of diffraction (TD-UTD) is developed for predicting the transient radiation and surface fields of elemental pulsed antennas placed directly on a smooth perfectly conducting, arbitrary convex surface. The TD-UTD solution is obtained by employing an analytic time transform (ATT) for inverting into time the corresponding frequency domain UTD (FD-UTD) solution. An elemental antenna on the convex surface is excited by a step function in time and a TD-UTD solution is obtained first. The TD-UTD response to a more general pulsed excitation of the elemental current is then found via an efficient convolution of the TD-UTD solution for the step function excitation with the time derivative of the general pulsed excitation. In particular, this convolution integral is essentially evaluated in closed form after representing the time derivative of the general pulsed excitation by a small sum of simple signals whose frequency domain description is a sum of complex exponential functions. Some numerical examples are presented to illustrate the utility of these TD-UTD solutions for pulsed antennas on a convex body.

Stress waves in kidney stones.

A 3‐D time‐domain finite‐difference solution to the linear elastic equations was applied to investigate the stress and velocity fields of kidney stones subject to lithotripsy shock waves. The kidney stone models were scanned from micro‐computed tomography and had diameters from 2 to 5 mm. It was found for these shapes that shear waves induced by interference of the shock wave with stone boundaries dominated the high stress in the stones. The traditional belief of stone comminution mechanism by spall mechanism does not play important role due to the irregular proximal and distal stone surfaces. It was found for natural stones that stone orientation had an impact on the generation of high stress with a smooth convex surface producing the highest internal stresses. The results indicate that lithotripters with a focal width larger than a stone should be able to break a stone more efficiently since the large focal width shock waves result in stronger interaction with stone circumferences and produce larger she...

A simple fabrication and integration technique of microlens for microfluidic lab-on-a-chip by overflow of UV resin through holes

In the present study, a simple fabrication technique for microlens or microlens array is proposed based on an overflow of a UV curable resin through micro-holes followed by photopolymerization of the resin. As a first step of the present technique, a micro-hole is precisely drilled on a flat plastic sheet. A UV curable resin is carefully spread over another plastic sheet, and then an overflow process is carried out by compressing the spread resin with the holed sheet. The overflowed resin through the hole is then cured by irradiation with UV light and consequently, the microlens is formed from the overflowed resin on the holed sheet. By utilizing the present fabrication technique, microlenses of 600 and 750 μm in diameter were successfully manufactured. The fabricated microlens was also characterized by measuring its detailed dimensions and focal length. The microlens of 750 μm in diameter showed a smooth convex surface and the focal length of 2.11 mm.