Stable Curves Research Articles

Behavior of new hybrid connection between steel beam and concrete-encased composite column

A new bending connection between a steel beam and concrete-encased composite column (CECS) with a bolted flange plate is proposed which maintains the integrity of the column and allows for the interchangeability of the beam for improvement of the connection. The confinement of the steel plates and the central steel core (H-section column) is provided by reinforced concrete and cover plates, thus lateral torsional and local buckling of the through plate (TP) and the central core is prevented. Three full-scale samples of the proposed exterior connection with variable TP thickness and different bending capacities under lateral cyclic and constant axial loads in the column were tested. The moment contribution in the components and seismic behavior of the connection were studied. The load transfer to the panel zone occurred through four components in the bending plane; TP, concrete performance, tensile studs, and side plates. The average share of the resistant elements which is immediately behind the front plate were determined as 56%, 26%, 12.50%, and 5.5%, respectively. The internal panel zone remained undamaged and the stresses were below the yield limit, so that the plastic hinge could occur outside the connecting members in the beam. In general, the specimens with sufficient pre-tensioning in the connection bolts had stable hysteresis curves and less pinching. In addition, these specimens showed acceptable energy dissipation that provided a high ductility index.

The Moduli Space of Cubic Threefolds with a Non-Eckardt Type Involution via Intermediate Jacobians

Abstract There are two types of involutions on a cubic threefold: the Eckardt type (which has been studied by the first named and the third named authors) and the non-Eckardt type. Here we study cubic threefolds with a non-Eckardt type involution, whose fixed locus consists of a line and a cubic curve. Specifically, we consider the period map sending a cubic threefold with a non-Eckardt type involution to the invariant part of the intermediate Jacobian. The main result is that the global Torelli Theorem holds for the period map. To prove the theorem, we project the cubic threefold from the pointwise fixed line and exhibit the invariant part of the intermediate Jacobian as a Prym variety of a (pseudo-)double cover of stable curves. The proof relies on a result of Ikeda and Naranjo–Ortega on the injectivity of the related Prym map. We also describe the invariant part of the intermediate Jacobian via the projection from a general invariant line and show that the two descriptions are related by the bigonal construction.

Comparison of MTFs Measured using IndoQCT and ImQuest Software on GE CT Phantom Images

Purpose: This study aims to compare the modulation transfer function (MTF) measured using IndoQCT and ImQuest software on GE CT phantom images with variations of slice thickness and reconstruction filter. Method: This study compared MTFs measured using two software (i.e., IndoQCT and ImQuest software) on GE CT phantom images. IndoQCT implemented automatic region of interest (ROI) determination, while ImQuest used manual ROI determination. Both software analysed images with three variations of slice thickness (i.e., 2.5, 5, and 10 mm) and reconstruction filter (i.e., standard, soft tissue, chest, and bone filters). Results: IndoQCT provides automatic ROI selection and produces stable MTF curves, while ImQuest provides manual ROI selection and produces more fluctuating MTF curves. In slice thickness variation, IndoQCT showed that different slice thickness did not significantly affect spatial resolution as suggested, while ImQuest showed significant differences in spatial resolution for thickest slice thickness. In filter variation, IndoQCT produced high spatial resolution value in bone filter, while ImQuest produced the lower spatial resolution value. Overall, both software showed MTF differences within 15%, except in certain conditions, for example on a slice thickness of 10 mm. Conclusions: We have compared MTFs measured using IndoQCT and ImQuest software. Both software can be used to measure MTFs on the GE phantom images with relatively accurate results. IndoQCT generally produces higher MTF values than those from ImQuest. However, the difference MTF is not statistically significant. This study found that at 10 mm slice thickness, ImQuest produced very low MTF, while IndoQCT produced stable results for different slice thicknesses and reconstruction filters.

Formulation Of Solid Soap From Kerinci Arabica Coffee Beans

Background: Kerinci coffee that is grown in the traditional way and gets a coffee stamp that applies a sustainable process. The caffeine content in coffee is an antioxidant that can prevent premature aging of the skin, is able to remove dead skin cells, smooth the skin, provide nutrition to the skin, eliminate body odor, remove acne scars and provide protection against ultraviolet rays. This study aims to obtain a good solid soap formula from Kerinci Arabica Coffee.
 Methods: Solid soap is made by the cold process method using a mixture of fatty oils and sodium hydroxide as the basic ingredients. The fatty oil used is a mixture of olive oil and coconut oil (Formula I/FI) and a mixture of olive oil and VCO (Formula II/FII).
 Results: Both formulas show good results in the form of solid, coffee-scented, milk chocolate color (FI) dark milk chocolate FII, FI soap has hard texture and FII has soft. The results of the test for water content FI = 11.3% and FII = 10.45%, the conditions according to SNI are less than 15%. The pH of FI soap is 9 and FII is 10, the pH test for 4 weeks shows a stable curve.
 Conclusion: Kerinci arabica coffee can be formulated into solid soap and meets the requirements for water content and pH

Research on the road performance of self-adhesive basalt fiber geotextiles based on the background of long-life pavements

Achieving sustained asphalt pavements can minimize the structural damage brought on by minor pavement cracks, which will reduce the high repair and maintenance costs resulting from pavement distress. This study introduces a new composite geomaterial, self-adhesive basalt fiber geotextiles (SBFG) prepared by hot-melt lamination of basalt fiber cloth and modified asphalt, intended for the deterrence and control of reflection cracks in asphalt pavements. In this study, the self-adhesive geotextile was placed between the cement-stabilized macadam base and AC-20 surface layer to prepare composite samples, and the road performance was evaluated by a three-point bending test, Overlay Tester, dynamic shear rheology test, and the crack expansion time under different parameters of SBFG was simulated by ABAQUS finite element to predict the whole life cycle of the pavement structure. The results indicate that the fracture energy of the SBFG sample is the largest among all samples, and the structural design of fiber reinforcement disperses the concentrated stress at the crack tip, increases the stress area, and prolongs the time of crack expansion from the subgrade to the surface layer; Smooth and stable load loss curve of the sample in the reflection crack test, with slow crack expansion. This new geomaterial has an excellent rutting factor and maintains good resistance to permanent deformation at high temperatures; In the finite element prediction of fatigue cracking life of asphalt pavement, the structural life of the pavement with the addition of SBFG was improved by 78.3% compared to the control group. The application of basalt fibers in geosynthetics provides a new idea for achieving prolonged asphalt pavements.

Blown-up toric surfaces with non-polyhedral effective cone

Abstract We construct projective toric surfaces whose blow-up at a general point has a non-polyhedral pseudo-effective cone. As a consequence, we prove that the pseudo-effective cone of the Grothendieck–Knudsen moduli space M ¯ 0 , n \overline{M}_{0,n} of stable rational curves is not polyhedral for n ≥ 10 n\geq 10 . These results hold both in characteristic 0 and in characteristic 𝑝, for all primes 𝑝. Many of these toric surfaces are related to an interesting class of arithmetic threefolds that we call arithmetic elliptic pairs of infinite order. Our analysis relies on tools of arithmetic geometry and Galois representations in the spirit of the Lang–Trotter conjecture, producing toric surfaces whose blow-up at a general point has a non-polyhedral pseudo-effective cone in characteristic 0 and in characteristic 𝑝, for an infinite set of primes 𝑝 of positive density.

Enhancement of the Lateral Performance of RC Columns Using Steel Jacketing: A Numerical Approach

Steel jacketing has become an attractive strengthening technique for reinforced concrete (RC) columns due to ease of construction and less space requirement. The steel cage consists of angle sections placed at corners and held together by battens at intervals along the RC column height. A numerical investigation of the effective use of steel jackets as a strengthening technique in RC columns is presented in this paper. First, the finite element models of the strengthened column were developed and validated using past experimental data. Then, with the validated model, six sets of steel jacket sections with modified cross-sections such as batten spacing, batten thickness, batten width, end batten width, L angle thickness and steel jacket height were tested under constant axial and lateral loading to understand the effectiveness of steel jackets as the strengthening technique. AnunstrengthenRC column were also analysed to compare the performance of a similar column strengthened by steel jackets with modified parameters. It was shown that strengthening RC columns with steel jackets was effective in enhancing the lateral performance of the columns and resulted in a more stable load-displacement curve with lower strength degradations as compared with the un-strengthened ones. Additionally, it was found that the most effective method to increase the lateral strength and ductility is increasing the L angle thickness. On the other hand, increasing the steel jacket height also increases the lateral performance, however, it was identified that increasing the jacket height is effective only up to 1/3rd of the RC column height. Finally, the obtained results for each parameter were compared to study the behaviour of each component of the steel jacket towards lateral strength and ductility improvements.

Fine Compactified Moduli of Enriched Structures on Stable Curves

Enriched structures on stable curves over fields were defined by Mainò in the late 1990s, and have played an important role in the study of limit linear series and degenerating jacobians. In this paper we solve three main problems: we give a definition of enriched structures on stable curves over arbitrary base schemes, and show that the resulting fine moduli problem is representable; we show that the resulting object has a universal property in terms of Néron models; and we construct a compactification of our stack of enriched structures.

Chow rings of stacks of prestable curves II

Abstract We continue the study of the Chow ring of the moduli stack 𝔐 g , n {\mathfrak{M}_{g,n}} of prestable curves begun in [Y. Bae and J. Schmitt, Chow rings of stacks of prestable curves I, Forum Math. Sigma 10 2022, Paper No. e28]. In genus 0, we show that the Chow ring of 𝔐 0 , n {\mathfrak{M}_{0,n}} coincides with the tautological ring and give a complete description in terms of (additive) generators and relations. This generalizes earlier results by Keel and by Kontsevich and Manin for the spaces of stable curves. Our argument uses the boundary stratification of the moduli stack together with the study of the first higher Chow groups of the strata, in particular providing a new proof of the results of Kontsevich and Manin.

On topological and combinatorial structures of pointed stable curves over algebraically closed fields of positive characteristic

AbstractIn this paper, we study anabelian geometry of curves over algebraically closed fields of positive characteristic. Let be a pointed stable curve over an algebraically closed field of characteristic and the admissible fundamental group of . We prove that there exists a group‐theoretical algorithm, whose input datum is the admissible fundamental group , and whose output data are the topological and the combinatorial structures associated with . This result can be regarded as a mono‐anabelian version of the combinatorial Grothendieck conjecture in the positive characteristic. Moreover, by applying this result, we construct clutching maps for moduli spaces of admissible fundamental groups.

Hexagonal cage like structured reduced graphene Oxide-NiCo2S4 nanocomposite for high performance hydrogen evolution reaction

In the present study, a facile and simple hydrothermal technique was employed for the preparation of reduced graphene oxide (rGO) incorporated NiCo2S4 and analyzed the hydrogen evolution reaction (HER) activity in alkaline media. The face centered cubic crystal structure is confirmed from the X-ray diffraction analysis and hexagonal cage like structure of NiCo2S4 was visualized by FESEM analysis. With the increased number of facets in hexagonal cage structure, the electrochemical-active surface area (ECSA) gets increased, and the HER performance gets increased for bare NiCo2S4. The additional ECSA is caused by the existence of rGO in the case of ternary nanocomposite (rGO-NiCo2S4). The obtained small over potential (370 mV) and small Tafel slope (139 mV/dec) proves the excellent HER activity of rGO-NiCo2S4 nanocomposite. The optimized rGO-NiCo2S4 as excellent HER electrocatalyst provides a highly stable polarization curve up to 10 h and it can be more useful to replace the high-cost platinum noble electrocatalyst.

Global Dynamics for Competition between Two Wolbachia Strains with Bidirectional Cytoplasmic Incompatibility

Releasing Wolbachia-infected mosquitoes to suppress or replace wild vector mosquitoes has been carried out in 24 countries worldwide, showing great promise in controlling mosquitoes and mosquito-borne diseases. To face the instability of Wolbachia infection in different environments during the area-wide application, we should consider the overlapping of two Wolbachia strains. In this case, bidirectional cytoplasmic incompatibility occurs, which results in mating partners infected with exclusive Wolbachia strains producing inviable offspring. To determine the better Wolbachia candidate for release, we develop an ordinary differential equation model to study the global dynamics for competition between two Wolbachia strains. Our theoretical results on the sharp estimate of stable curves completely determine the fate of the two Wolbachia strains, which help choose appropriate strains for release.

Polynomial Relations Among Kappa Classes on the Moduli Space of Curves

Abstract We construct an infinite collection of universal—independent of $(g,n)$—polynomials in the Miller–Morita–Mumford classes $\kappa _m\in H^{2m}( \overline{\mathcal{M}}_{g,n},{\mathbb{Q}})$, defined over the moduli space of genus $g$ stable curves with $n$ labeled points. We conjecture vanishing of these polynomials in a range depending on $g$ and $n$.

Porous In2O3–ZnO nanofiber-based sensor for ultrasensitive room-temperature detection of toluene gas under UV illumination

Toluene gas is hazardous but plays a vital role in several industries. Hence, the detection of toluene gas is important for human health and the environment. In this study, porous In2O3–ZnO nanofibers were prepared via a facile electrospinning method to fabricate a toluene gas sensor. Illumination by ultraviolet light (365 nm) was used to realize the room temperature (RT) operation of the fabricated sensor. The structural properties of the sensor were studied using various characterization techniques. The prepared nanofibers consisted of many sub-nanograins, particularly ZnO and In2O3, and contained numerous pores in-between the nanograins. Consequently, these nanofibers had a large surface area, increasing the probability of contact between the gas and sensor. The prepared sensors were functional at RT under UV illumination and showed excellent toluene-sensing properties. The porous In2O3-appended ZnO-nanofiber-based sensors showed more stable and sensitive response curves than those of the pure ZnO nanofiber–based sensor. Moreover, In2O3-appended ZnO nanofiber sensors could only faintly detect other gases, such as NO2, acetone, ethanol, H2S, and CO gases, indicating that the sensor exhibits highly selective toluene sensing.

DC Motor Speed Control with Proportional Integral Derivative (PID) Control on the Prototype of a Mini-Submarine

DC (Direct Current) motors are widely used as controllers in the industrial and robotics fields. In the rotation of the DC motor, there is still an unstable rotational speed so that a controller is needed to be able to stabilize the speed at the rotation of the DC motor. The control used in this study used the PID (Proportional Integral Derivative) control method. The PID control system works by processing calculations based on control variables Kp, Ki, and Kd to achieve conditions according to the expected setpoints. To achieve the expected conditions, the trial and error method is used. PID control in this study was implemented on a DC motor with a brushed type using an Arduino Mega microcontroller. The speed of the DC motor is read by the encoder sensor and entered in the PID equation. The output of the PID value will produce data in the form of PWM (Pulse Width Modulation) which will be the input of the L298N driver via Arduino Mega. The DC motor will produce a rotational speed in the form of RPM (Revolution Per Minute) data up to the specified set point. The implementation of PID was produced by giving parameter values to Kp, Ki, and Kd. The best PID parameter usage in this study was in the form of Kp = 0.6; Ki=0.3; and Kd=0.01. The application of the PID parameter obtains a stable system response curve at a predetermined set point. The resulting Kp, Ki, and Kd parameter data is used as graph data in MATLAB software.

Gromov–Witten theory of complete intersections via nodal invariants

AbstractWe provide an inductive algorithm computing Gromov–Witten invariants in all genera with arbitrary insertions of all smooth complete intersections in projective space. We also prove that all Gromov–Witten classes of all smooth complete intersections in projective space belong to the tautological ring of the moduli space of stable curves. The main idea is to show that invariants with insertions of primitive cohomology classes are controlled by their monodromy and by invariants defined without primitive insertions but with imposed nodes in the domain curve. To compute these nodal Gromov–Witten invariants, we introduce the new notion of nodal relative Gromov–Witten invariants. We then prove a nodal degeneration formula and a relative splitting formula. These results for nodal relative Gromov–Witten theory are stated in complete generality and are of independent interest.

Smoothability of relative stable maps to stacky curves

Using log geometry, we study smoothability of genus zero twisted stable maps to stacky curves relative to a collection of marked points. One application is to smoothing semi-log canonical fibered surfaces with marked singular fibers.

The possible mechanism of direct feedback projections from basal ganglia to cortex in beta oscillations of Parkinson’s disease: A theoretical evidence in the competing resonance model

In this paper, we use a cortex-basal ganglia resonance network to explore the possible Hopf bifurcation mechanism of beta oscillation. Different from traditional viewpoints, this model contains a direct inhibitory projection from the subthalamic nucleus (STN) to the cortex excitatory nuclei (EXN). First, we obtain the oscillation critical conditions of the delay by Hopf bifurcation analysis. Then, we explore the effects of some key parameters on Hopf bifurcation points. Delay is an indispensable factor in this model, oscillations will occur only when delay increases to a certain extent. Interestingly, the amplitude of oscillation increases with an increase in delay, but the trend of frequency is opposite; and heterogeneous delays have different effects on amplitude and frequency. The inhibitory coupling weight in the pathway “STN→EXN” can reduce the firing activation level of cortical circuit, and the increase of coupling weights in the closed loop of the STN and globus pallidus external (GPe) can disinhibition this effect. On the stable boundary curve, the quantitative relationship of coupling weights between the direct and indirect projection from the basal ganglia to cortex is monotonously increasing. An increase in some critical coupling weights in the model, the bidirectional Hopf bifurcations (supercritical and subcritical) occur alternately, which can uniformly explain the origin mechanism of oscillations. In the inhibition-excitation closed loops, the excitatory and inhibitory connection weights have different effects on oscillations, the quantitative relationship of which is monotonically decreasing under Hopf bifurcation critical conditions. In the oscillation region, we observe that the amplitude is the smallest near bifurcation points and gradually increases with the evolution of oscillations. Finally, we find that the direct inhibitory projection from the STN to the EXN is a key pathway for external stimuli to control cortical oscillations. All theoretical analysis results compares well to numerical simulations, we hope that theoretical mechanisms obtained in this paper can inspire experimental research in Parkinson’s disease.

On the rank of general linear series on stable curves

We study the dimension of loci of special line bundles on stable curves and for a fixed semistable multidegree. In case of total degree d=g-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$d = g - 1$$\\end{document}, we characterize when the effective locus gives a Theta divisor. In case of degree g-2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$g - 2$$\\end{document} and g, we show that the locus is either empty or has the expected dimension. This leads to a new characterization of semistability in these degrees. In the remaining cases, we show that the special locus has codimension at least 2. If the multidegree in addition is non-negative on each irreducible component of the curve, we show that the special locus contains an irrreducible component of expected dimension.

Experimental and numerical study of undersized shear panel dampers with bolted connections

Shear panel dampers have been widely utilised in steel structures to enhance structural damping and dissipate earthquake energy, and thus minimise damage to primary structures. These shear panel dampers commonly feature relatively large sizes and high loading resistance owing to their main applications in multi-storey and high-rise buildings. In contrast, this study intended to develop an undersized shear panel damper (USPD) for prefabricated low-rise structures without site welding. To investigate the cyclic behaviour and fracture characteristics, USPDs made of Q235 low-carbon steel were designed as full-scale specimens with bolted connections and then tested under cyclic shear loads. Moreover, finite element (FE) models were established by considering the material and geometric nonlinearities. The ultralow cycle fatigue (ULCF) fracture initiation life of the USPDs was further predicted based on the cyclic void growth model (CVGM) and validated against the test results. Accordingly, the USPDs exhibited plump and stable hysteresis curves before crack propagating severely and featured significant cyclic hardening behaviour, where the ultimate-to-yield resistance ratio ranged from 2.20 to 2.45. The presented FE models could simulate the cyclic behaviour of USPDs well, and the CVGM accurately predicted the ULCF fracture initiation life with the average discrepancy of 14.8%. The results demonstrate the potential applicability of USPDs, and the developed FE analysis method considering ULCF fractures provides a solution for further configuration optimisations and parametric analyses, reducing the cost of experimental studies.