Double Steps Research Articles

Ultrasound synthesis of lanthanide complexes: Crystal structure, thermal decomposition kinetics and fluorescence properties

Two binuclear complexes were successfully synthesized by ultrasound method:[Ln(2-Cl-6-FBA)3(5,5′-DM-2,2′-bipy)(H2O)]2, (Ln=Tb(1), Dy(2); 2-Cl-6-FBA=2‑chloro-6-fluorobenzoicacid; 5,5′-DM-2,2′-bipy=5,5′-dimethyl-2,2′-bipyridine). The crystal structure analysis showed that the two complexes were isomorphic. And they were characterized by IR spectra, Raman spectra and XRD. The fluorescence properties of complex 1 were studied and its luminescence lifetime was calculated. Subsequently, the heat capacity of the two complexes were measured and their thermodynamic functions were obtained. TG-DTG/FTIR/MS technique was used to test the thermal decomposition of the complex in order to better understand the thermal decomposition behavior. Complex 1 was tested at different heating rates to study its non-isothermal kinetics. The relationship between activation energy E and conversion rate α was calculated by M. J. Starink method and NL-INT method. The mechanism functions in the third step decomposition process were determined by double equal-double steps method as G(α) = 1-(1-α)1/2 and f(α) = 2(1-α)1/2. The activation energy E and the pre-exponential factor A were calculated, a series of thermodynamic parameter of the complex were obtained by the equations.

Tilted Spins in Chains of Molecular Switches on Pb(100).

A complex based on a Ni(II) porphyrin exhibiting spin crossover on Ag(111) is studied on Pb(100) by scanning tunneling microscopy at 0.3 K. Strong molecular interactions between the phenyl and pentafluorophenyl moieties lead to the formation of molecular chains and cause a faceting of the substrate surface. The chains are located along double and multiple substrate steps that deviate from high-symmetry directions. Tunneling spectroscopy reveals spin-flip excitations of an S = 1 system. Measurements in high magnetic fields are used to identify a tilt of the complex and its hard anisotropy axis with respect to the surface normal. Electron injection into the substrate near the molecular rows induces a transition to a state with larger inelastic cross section, leaving the spin state unchanged.

A Method with Double Inertial Type and Golden Rule Line Search for Solving Variational Inequalities

In this work, we study a new line-search rule for solving the pseudomonotone variational inequality problem with non-Lipschitz mapping in real Hilbert spaces as well as provide a strong convergence analysis of the sequence generated by our suggested algorithm with double inertial extrapolation steps. In order to speed up the convergence of projection and contraction methods with inertial steps for solving variational inequalities, we propose a new approach that combines double inertial extrapolation steps, the modified Mann-type projection and contraction method, and the line-search rule, which is based on the golden ratio (5+1)/2. We demonstrate the efficiency, robustness, and stability of the suggested algorithm with numerical examples.

Viscosity extragradient algorithms with double inertial extrapolation steps for quasimonotone variational inequalities and fixed point problems

We study two viscosity extragradient algorithms with double inertial extrapolation steps for finding a common solution of a variational inequality governed by a quasimonotone operator and of a fixed point problem with a demicontractive mapping in a real Hilbert space. The strong convergence theorems are proved under certain appropriate conditions. The step sizes of our algorithms are updated by simple calculations without knowing the prior information of the operator norms. Numerical examples in finite- and infinite-dimensional spaces are given to show the performance of the proposed algorithms.

A proximal gradient method with double inertial steps for minimization problems involving demicontractive mappings

In this article, we present a novel proximal gradient method based on double inertial steps for solving fixed points of demicontractive mapping and minimization problems. We also establish a weak convergence theorem by applying this method. Additionally, we provide a numerical example related to a signal recovery problem.

Numerical Investigation of Single and Double Steps in Planing Hulls

Incorporating steps into a hull reduces the wetted surface, promoting improved hydrodynamic lift and reduced resistance at high speeds, provided that the step is designed appropriately. Traditional hydrodynamics studies rely on scaled model testing in towing tanks, but numerical tools offer a more efficient alternative. This study focused on investigating the hydrodynamic performance of stepped hulls by modifying the parent hull of the Naples Systematic Series (C1). The Computational Fluid Dynamics (CFD) code SIEMENS PLM STAR CCM+ version 2302 was used for simulations, including four different beam Froude numbers (FrB = 1.13, 2.22, 2.56, and 2.96) and a total of 15 hull configurations with single and double steps. By employing a three-dimensional computational analysis of multiphase flow using Dynamic Fluid–Body Interaction (DFBI) and overset mesh, various performance parameters such as resistance coefficient, dimensionless wetted surface, sinkage, and dynamic trim were analyzed. The accuracy of the CFD results was confirmed through comparison with experimental data and grid uncertainty assessment. The study demonstrated that placing a single step near the transom decreased trim and increased resistance and wetted surface. Conversely, positioning a step in the forward section reduced the trim angle at lower step heights but increased trim at higher step heights in single-stepped hulls. The application of these findings contributes to the design optimization of stepped hulls for enhanced performance in high-speed maritime applications.

Self-adaptive Technique with Double Inertial Steps for Inclusion Problem on Hadamard Manifolds

AbstractIn this article, we investigate monotone and Lipschitz continuous variational inclusion problem in the settings of Hadamard manifolds. We propose a forward–backward method with a self-adaptive technique for solving variational inclusion problem. To increase the rate of convergence of our proposed method, we incorporate our iterative method with double inertial steps and establish a convergence result of our iterative method under some mild conditions. Finally, in order to illustrate the computational effectiveness of our method, some numerical examples are also discussed. The result present in this article is new in this space and extends many related results in the literature.

Projection and contraction method with double inertial steps for quasi-monotone variational inequalities

In this paper, we present a modified projection and contraction method for solving quasi-monotone variational inequalities in real Hilbert spaces. Our proposed method is a combination of double inertial extrapolation steps, the subgradient extragradient method and the projection contraction method, which can effectively accelerate the convergence rate. The weak and linear convergence have been obtained under some suitable conditions. Some numerical experiments are given to show that our proposed method outperforms the related methods.

Double inertial Forward–Backward–Forward method with adaptive step-size for variational inequalities with quasi-monotonicity

The paper introduce a new inertial forward–backward–forward method with adaptive step size constructed by double inertial extrapolation steps and relaxations to solve variational inequalities with quasi-monotonicity in real Hilbert spaces. We obtain weak and strong convergence results for our propose inertial Forward–Backward–Forward method under some mild conditions. Linear convergence results under a special case of our proposed method are given. Preliminary numerical results show that our proposed method is competitive with other related methods in the literature.

Observing temporary changes in gait using a mobile phone

The purpose of the article is to analyze temporary changes in human gait, the parameters of which are recorded using the accelerometer of a mobile phone in everyday use. The work presents trends in the field of personalized medicine and monitoring the health of employees in the manufacturing sector based on wearable and mobile devices. The features of collecting and processing data on a person’s gait using a mobile phone are presented, which act as a comprehensive assessment of human health parameters. The results of a year-long research of changes in human gait are presented. Daily, weekly and annual trends are identified. The research analyzed mobile phone accelerometer time series representing double steps during gait. When constructing trends, the maximum value of the cross-correlation function of data segments was used. Data segmentation was carried out according to the length of the double step. Based on the results of the research, an assumption is made about the possibility of recording individual characteristics of the functioning of the human musculoskeletal system using a mobile phone and conducting further research in order to accumulate statistical material and identify the relationship between a person’s lifestyle and changes in gait parameters.

Double inertial steps extragadient-type methods for solving optimal control and image restoration problems

<abstract><p>In order to approximate the common solution of quasi-nonexpansive fixed point and pseudo-monotone variational inequality problems in real Hilbert spaces, this paper presented three new modified sub-gradient extragradient-type methods. Our algorithms incorporated viscosity terms and double inertial extrapolations to ensure strong convergence and to speed up convergence. No line search methods of the Armijo type were required by our algorithms. Instead, they employed a novel self-adaptive step size technique that produced a non-monotonic sequence of step sizes while also correctly incorporating a number of well-known step sizes. The step size was designed to lessen the algorithms' reliance on the initial step size. Numerical tests were performed, and the results showed that our step size is more effective and that it guarantees that our methods require less execution time. We stated and proved the strong convergence of our algorithms under mild conditions imposed on the control parameters. To show the computational advantage of the suggested methods over some well-known methods in the literature, several numerical experiments were provided. To test the applicability and efficiencies of our methods in solving real-world problems, we utilized the proposed methods to solve optimal control and image restoration problems.</p></abstract>

Double inertial extrapolations method for solving split generalized equilibrium, fixed point and variational inequity problems

<abstract><p>This article proposes an iteration algorithm with double inertial extrapolation steps for approximating a common solution of split equilibrium problem, fixed point problem and variational inequity problem in the framework of Hilbert spaces. Unlike several existing methods, our algorithm is designed such that its implementation does not require the knowledge of the norm of the bounded linear operator and the value of the Lipschitz constant. The proposed algorithm does not depend on any line search rule. The method uses a self-adaptive step size which is allowed to increase from iteration to iteration. Furthermore, using some mild assumptions, we establish a strong convergence theorem for the proposed algorithm. Lastly, we present a numerical experiment to show the efficiency and the applicability of our proposed iterative method in comparison with some well-known methods in the literature. Our results unify, extend and generalize so many results in the literature from the setting of the solution set of one problem to the more general setting common solution set of three problems.</p></abstract>

EVALUATION OF PLATELET RICH PLASMA (PRP) PREPARATION PROCEDURE

The success of PRP therapy in repairing tissue damage is influenced by the PRP preparation procedure. Currently, there’s no standardization of PRP preparation procedures, and various techniques are used, such as the use of anticoagulants and different centrifugation speeds. This study aimed to evaluating the PRP preparation procedures based on the centrifugations steps (single and double centrifugation) and the use of anticoagulants variation (sodium citrate, EDTA and ACD-A). This study was an experimental study and used blood samples from respondents. The selected respondents must meet inclusion and exclusion criteria. The treatment groups in this study were the single centrifugation group and the double centrifugation group. Each group will be divided into 3 subgroups with different anticoagulant usage (sodium citrate, EDTA and ACD-A). Statistical analysis results showed a significant difference in the mean platelet count in the sodium citrate , EDTA, ACD-A groups with single and double centrifugation steps. Evaluation of platelet preparation procedures in this study, a higher platelet count was obtained, specifically in the sodium citrate group (494 x 103 cells/µL), EDTA group (829.4 x 103 cells/µL), and ACD-A group (607.1 x 103 cells/µL), compared to single centrifugation in the sodium citrate group (354.8 x 103 cells/µL), EDTA group (408.1 x 103 cells/µL), and ACD-A group (390.6 x 103 cells/µL). The highest platelet count in PRP was achieved with the preparation procedure using EDTA as the anticoagulant with double centrifugation. Further research is necessary to evaluate PRP preparation procedures regarding the concentration of growth factors present in PRP.

Relaxed Tseng splitting method with double inertial steps for solving monotone inclusions and fixed point problems

Relaxed Tseng splitting method with double inertial steps for solving monotone inclusions and fixed point problems

CORAK HERMENEUTIKA AL MAWARDI DALAM KITAB AL-NUKAT WA AL ‘UYŪN

The discourse of hermeneutics (interpretation) of the Qur'an becomes an interesting and factual study. Examining one of the monumental works of the Mufassir figures that should be taken into account is Shaykh al Mawardi. He is not only a bureaucrat who served as a Supreme Judge but also a Mufassir who should be used as a reference in ideas and thoughts. Through the work of al-Nukat wa al-'Uyūn, al Mawardi tries to offer a style of interpretation that combines the method of history (Naql) by involving linguistic reviews, grammar and jurisprudence, while the other side al Mawardi also used ijtihadi method (khalaf) by quoting and comparing the opinions of Mufassir. These two double steps are the distinction from other Mufassir, so the author tries to present and disseminate the style of interpretation of al Mawardi. This research is a literature study of the work of tafsir al Mawardi through a review of descriptive analysis of his interpretation method. The findings in the study indicate that al Mawardi has a distinctive method, namely the style of interpretation that tries to accommodate classical and contemporary models of interpretation (Ijtihādi) by citing some opinions of previous Mufassir and Fuqohā'.

Analysis of the double steps position effect on planing hull performances

Along with developing high-speed craft technology, the planing hull is growing with modifications for better performance. One such technology is stepped hull, both single and double. Planing hull with steps allows the boat to run at a relatively low drag-lift ratio with lower frictional resistance due to reduced wetted area. In this study, the hull was modified with variations in the position of the double steps, which aimed to determine the effect of the first and second step positions on the total resistance, dynamic trim, and dynamic sinkage generated by computational fluid dynamics (CFD). Based on the analysis results, variations in the position of the stepped can change the hull performance. Shortening the distance between the two steps and moving both rearwards toward the transom can lower the total resistance. The dynamic trim and dynamic sinkage decreased as the position of the two steps was shifted further forward. An equation created in a non-dimensional form relates the positions of two steps to the desired results of total resistance, dynamic trim, and dynamic sinkage, namely: {(x1-x2)/L + (x1x2)/(LB)} × Fr∇, where x1 is distance the first step from transom, x2 is the distance of the second step, L is the length of the boat, B is the beam of the boat, and Fr∇ is the volume Froude number.

A Modified Tseng Splitting Method with Double Inertial Steps for Solving Monotone Inclusion Problems

A Modified Tseng Splitting Method with Double Inertial Steps for Solving Monotone Inclusion Problems

Numerical Study of Optimum Configuration of Unconventional Airfoil with Steps and Rotating Cylinder for Best Aerodynamics Performance

Numerical study of separation control on symmetrical airfoil, four digits (NACA
 0012) by using rotating cylinder with double steps on its upper surface based on the computation of Reynolds-average Navier- Stokes equations was carried out to find the optimum configuration of unconventional airfoil for best aerodynamics performance. A model based on collocated Finite Volume Method was developed to solve the governing equations on a body-fitted coordinate system. A revised (k-w) model was proposed as a known turbulence model. This model was adapted to simulate the control effects of rotating cylinder. Numerical solutions were performed for flow around unconventional airfoil with cylinder to main stream velocities ratio in the range of 1 to 4 and for various positions of the steps on the airfoil from the leading edge, 0.1c, 0.2c, 0.3c, 0.4c, 0.5c for the first step and 0.5c, 0.6c, 0.7c, 0.8c for the second step with constant step depth and length of 0.03c and 0.125c respectively. Reynolds number of 700,000 which was based on the cord length (c), with angle of attacks 0, 5, 8, 10, 12, 15 degrees was considered for the assessment of the unconventional airfoil performance. The numerical investigation showed that the optimum configuration for the unconventional airfoil was found to be at velocities ratio (U/U∞=4) with the steps positions at 0.5c and 0.8c for best airfoil performance.

Double deposition/accumulation and double stripping steps system as a new way of decreasing the detection limit and elimination of interferences in stripping voltammetry of inorganic ions: A review

AbstractThe article reviews an application of double deposition/accumulation and stripping steps as a new and beneficial manner of decreasing a detection limit and/or interferences elimination in stripping voltammetric determination of inorganic ions: Pb(II), Cd(II), Tl(I), U(VI), Au(III), As(III), Se(IV), In(III), Co(II), Cu(II), Bi(III) and Ga(III). A simple design of four‐electrodes system, containing two working electrodes differing in their surface area, allows for conducting two preconcentration and two stripping steps in one measurement cycle and in one voltammetric cell. Considerable analytes preconcentration and, consequently, an increase of sensitivity of determinations was obtained by conducting the first stripping step in a small volume of a solution near the microelectrode surface. An appropriate selection of the conditions of the first deposition/accumulation and the first stripping steps allowed for a minimization/elimination of interference effects. The proposed procedures allows for ultra‐trace levels determinations of mentioned inorganic ions (often impossible to determine by means of traditional three‐electrodes systems) without additional preconcentration outside the electrochemical cell and with the use of mercury‐free electrodes.

High temperature plasticity at twin boundary in Al: An in-situ TEM perspective

Coherent twin boundaries are of special importance in structural materials due to their strengthening ability by impeding dislocation motion while maintaining possible glide along their plane. Interactions of lattice dislocations with twin boundaries have been extensively studied experimentally and numerically but relaxation and deformation processes at high temperature are not fully understood. The reason is related to complex mechanisms of dislocation decompositions into disconnections, their further motion and possible reactions. Moreover, as in shear-coupled grain boundary (GB) mechanisms, motion of disconnections in the interface plane is expected to lead to twin motion perpendicular to its plane. Here, shear-coupled motion of a coherent twin in pure Al is explored during in situ straining in a transmission electron microscope (TEM) in a favorable geometrical configuration. Surprisingly, the twin boundary does not couple to shear but slightly migrates by propagating nanoscale incoherent facets. Although, disconnections of Burgers vector 1/6〈112〉 have been extensively observed moving in the interface plane, their motion did not lead to migration as expected but presumably to GB sliding. This was interpreted by the motion of disconnections with opposite single and double steps in the [111] direction. Extensive dislocation/GB interactions were observed and reactions following absorption are interpreted by contrast analysis and motion observations. Incoming dislocations do not always decompose but often react with the GB disconnection microstructure which may lead to intergranular motions or dislocation emissions in the adjacent grain. As these processes usually involve disconnection climb in the interface plane, direct transmission, i.e. spatially and temporally correlated absorption/emission processes, is not observed as revealed by large scale observations. Finally, the internal disconnection microstructure of the twin boundary often forms networks which although flexible are found to slow down intergranular plasticity. Such networks should strongly control stress induced mechanisms in realistic GBs.