Reverse Forwarding Research Articles

Three-phase Electric Motor Control with a Manual Forward Reverse Control System Equipped with a Delay Timer

The control of three-phase electric motors with manual forward and reverse control systems equipped with off-timers (TOF) is a production solution with a simple structure and relatively low cost compared to other systems. Three-phase induction motors typically work via electromagnetic induction from the stator winding to the rotor, making them the preferred choice in both large and small industries due to their accommotivity and efficiency. The purpose of this study was to determine and analyze the control of a three-phase electric motor with a manual back and forth control system equipped with a delay timer. The research method used is secondary data analysis from various relevant and valid sources. The results showed that the manual back and forth control system with TOF is very effective in moving production equipment efficiently and reliably. The implications of this study show that with current technological developments, the use of three-phase electric motors with manual back and forth control systems equipped with TOF has become very important in improving operational efficiency and effectiveness in the industrial world.

Evaluation of Breaking Force of Different Suture Materials Used in Dentistry: An In Vitro Mechanical Comparison.

The success of surgical procedures is strictly related to the biomechanical properties of the suture. Mechanical comparisons are scarcely reported in the literature, so the purpose of the present study was to evaluate and compare the mechanical behavior of different sutures commonly used in oral surgery in terms of traction resistance. Sutures made of eight different materials were analyzed: silk (S), polyglycolide-co-caprolactone (PGCL), polypropylene (PP), rapid polyglycolide (rPGA), standard polyglycolide (PGA), polyamide (PA), polyester (PE), and polyvinylidene fluoride (PVDF). For each material, three different sizes were tested: 3-0, 4-0, and 5-0. The breaking force of each suture was assessed with a uniaxial testing machine after being immersed in artificial saliva at 37 °C. The outcomes analyzed were the breaking force, the needle–thread detachment breaking-point and the node response after forward–reverse–forward (FRF) tying when subjected to a tensile force. The 3-0 rPGA provided the maximum resistance, while the lowest value was recorded for the 5-0 PGCL. In general, 3-0 and 4-0 gauges showed non-statistically significant differences in terms of needle–thread detachment. The highest needle–thread detachment was found for the 3-0 PGA, whereas the lowest value was observed for the 5-0 PGCL. After tying the knot with an FRF configuration, the thread that showed the highest resistance to tension was the 3/0 silk, while the thread with the lowest resistance was the 5/0 silk. These data should be considered so that the operator is aware of as many aspects as possible on the behavior of various materials to ensure successful healing.

Influence of Charge Transport Layers on Open-Circuit Voltage and Hysteresis in Perovskite Solar Cells

Summary Perovskite materials have experienced an impressive improvement in photovoltaic performance due to their unique combination of optoelectronic properties. Their remarkable progression, facilitated by the use of different device architectures, compositional engineering, and processing methodologies, contrasts with the lack of understanding of the materials properties and interface phenomena. Here we directly target the interplay between the charge-transporting layers (CTLs) and open-circuit potential ( V OC ) in the operation mechanism of the state-of-the-art CH 3 NH 3 PbI 3 solar cells. Our results suggest that the V OC is controlled by the splitting of quasi-Fermi levels and recombination inside the perovskite, rather than being governed by any internal electric field established by the difference in the CTL work functions. In addition, we provide novel insights into the hysteretic origin in perovskite solar cells, identifying the nature of the contacts as a critical factor in defining the charge accumulation at its interface, leading to either ionic, electronic, or mixed ionic-electronic accumulation.

Physical and Mechanical Evaluation of Five Suture Materials on Three Knot Configurations: An in Vitro Study.

The aim of this study was to evaluate and compare the mechanical properties of five suture materials on three knot configurations when subjected to different physical conditions. Five 5-0 (silk, polyamide 6/66, polyglycolic acid, glycolide-e-caprolactone copolymer, polytetrafluoroethylene) suture materials were used. Ten samples per group of each material were used. Three knot configurations were compared A.2=1=1 (forward–forward–reverse), B.2=1=1 (forward–reverse–forward), C.1=2=1 (forward–forward–reverse). Mechanical properties (failure load, elongation, knot slippage/breakage) were measured using a universal testing machine. Samples were immersed in three different pH concentrations (4,7,9) at room temperature for 7 and 14 days. For the thermal cycle process, sutures were immersed in two water tanks at different temperatures (5 and 55 °C). Elongation and failure load were directly dependent on the suture material. Polyglycolic acid followed by glycolide-e-caprolactone copolymer showed the most knot failure load, while polytetrafluoroethylene showed the lowest (p < 0.001). Physical conditions had no effect on knot failure load (p = 0.494). Statistically significant differences were observed between knot configurations (p = 0.008). Additionally, individual assessment of suture material showed statistically significant results for combinations of particular knot configurations. Physical conditions, such as pH concentration and thermal cycle process, have no influence on suture mechanical properties. However, knot failure load depends on the suture material and knot configuration used. Consequently, specific suturing protocols might be recommended to obtain higher results of knot security.

Network coding with crowdsourcing-based trajectory estimation for vehicular networks

It is a great challenge to transmit data in vehicular networks, where the link among nodes is very shaky because of the rapid movement of vehicles. In this paper, we propose a Network Coding with Crowdsourcing-based Trajectory Estimation (NC/CTE) method to transmit data in vehicular networks. Key points are designated beforehand in movement area. Every node estimates which of Key points the other nodes in the discovered area close to at the different times. The estimation is completed by every node in crowdsourcing method based on the pre-trajectory of GPS navigation. Network coding, recoding and reverse forwarding are used for data transmission according to the result of trajectory estimation. Simulation results show that NC/CTE is able to cut down 1/2 overhead messages of TBNC when mobile nodes have shared their GPS trajectories. It improves the reliability and scalability of vehicular networks.

Optimization of Process Parameters in Injection Moulding of FR Lever Using GRA and DFA and Validated by Ann

This study deals with the optimization of the injection moulding process parameters in the production of the FR (Forward Reverse) Lever, using the Grey Relational Analysis (GRA) and Desirability Function Approach (DFA) and the results are validated by ANN. The FR lever is used to control the direction of the rotation of spindles in conventional machines. Parameters such as injection pressure, injection speed and injection temperature, which influence the quality of the final product of the injection moulding process, are called the input parameters. Parameters such as Shrinkage and Surface Roughness, which are considered as the quality characteristics of this product, are called the output parameters. FR levers are produced using a fabricated Injection moulding tool, according to Taguchi’s experimental design and the response data are recorded. The recorded experimental data are analyzed and the optimum process parameters combinations have been found, by using the GRA and DFA. An ANN has been developed using the experimental data and the responses (output data) are predicted for the corresponding optimal parameters combination. Finally, the obtained optimum parameter combinations are tested by both ANN and the experiment and the results are found to be satisfactory.

Implementation of the forward-reverse method for calculating the potential of mean force using a dynamic restraining protocol.

We present a new sampling and analysis scheme for calculating the potential of mean force (PMF) of systems studied by steered molecular dynamics simulations. This scheme, which we call the bin-passing method, is based on the forward-reverse (FR) method (due to I. Kosztin and co-workers, Kosztin et al. J. Chem. Phys. 2006, 124(6), 064106) and arguments based on the second law of thermodynamics. Applying the bin-passing method results in enhanced sampling, better separation of the reversible and irreversible work distributions, and faster convergence to the underlying PMF of the system under study. Post-simulation analysis is performed using a purpose-built software that we have made publicly available at https://github.com/1particle/bin-passing_analyzer under the terms of the GNU General Public License (version 3). Three examples are provided, for systems of varying sizes and complexities, to demonstrate the efficiency of this method and the quality of the results: for the dissociation PMF of NaCl in water, the bin-passing method obtains PMFs in excellent agreement with that obtained for the same system and using the same force-field through static (equilibrium) methods. The bin-passing method gives a very symmetric PMF for passage of a single water molecule through a DPPC bilayer, and the resultant PMF leads to permeability values in better agreement with experiments than those obtained through previous simulation studies. Finally, we consider the interaction of the antimicrobial peptide HHC-36 with two model membranes and employ the bin-passing method to obtain the PMFs for peptide adsorption to the membranes. The characteristics of these PMFs are consistent with the qualities established for the HHC-36 peptide through in vivo and in vitro experiments, as a non-toxic strong antimicrobial agent.

The Simultaneous Determination of Diffusion Coefficients and PMFs Through the OFR Method

Progress in nonequilibrium, bidirectional work theorems have lead to the development of an important theory, known as the forward-reverse (FR) method, that allows the PMF to be extracted from nonequilibrium dynamics. In addition, the FR method allows the simultaneous determination of the reaction coordinate dependent diffusion coefficient, D(z). We recently extended the utility of the FR method through the use of an oscillating steering protocol that we named the oscillating forward-reverse (OFR) method. While working with OFR, the D(z) results did not match known values or those obtained through other methods. After reformulating the procedure to obtain D(z), we were able to obtain results close to the correct values. These results however showed very little variation over the length of the reaction coordinate, even when D(z) was known to vary drastically. It seemed that the highly variable and noncontinuous velocity function of the particle - a consequence of being steered using the “stiff-spring” method - was incompatible with the macroscopic definition of the drag coefficient through which D(z) is calculated. To address this, a new dynamic constraint steering protocol (DCP) was developed to replace the previously used “stiff-spring” method. We present here the results for D(z) in bulk water, and both the PMF and D(z) results from the permeation of a water molecule through a DPPC membrane. We also consider the issue of sufficient sampling, and propose that to obtain an accurate PMF (and D(z)) from even a moderately complex system, the final result should be a weighted average of numerous pulls. This is actually an advantage of nonequilibrium over equilibrium methods, the latter having a limited ability to sample much phase space beyond their initial conditions - especially with the time-scales currently available in computer simulations.

Drift-oscillatory steering with the forward-reverse method for calculating the potential of mean force

We present a method that enables the use of the forward-reverse (FR) method of Kosztin et al. on a broader range of problems in soft matter physics. Our method, which we call the oscillating forward-reverse (OFR) method, adds an oscillatory steering potential to the constant velocity steering potential of the FR method. This enables the calculation of the potential of mean force (PMF) in a single unidirectional oscillatory drift, rather than multiple drifts in both directions as required by the FR method. By following small forward perturbations with small reverse perturbations, the OFR method is able to generate a piecewise reverse path that follows the piecewise forward path much more closely than any practical set of paths used in the FR method. We calculate the PMF for four different systems: a dragged Brownian oscillator, a pair of atoms in a Lennard-Jones liquid, a Na(+)-Cl⁻ ion pair in an aqueous solution, and a deca-alanine molecule being stretched in an implicit solvent. In all cases, the PMF results are in good agreement with those published previously using various other methods, and, to our knowledge, we give for the first time PMFs calculated by nonequilibrium methods for the Lennard-Jones and Na(+)-Cl⁻ systems.

Drift-Oscillatory Steering with the Forward-Reverse Method for Calculating the Potential of Mean Force

We present a method that enables the use of the forward-reverse (FR) method of Kosztin et al. on a broader range of problems in soft matter physics. Our method, which we call the oscillating forward-reverse (OFR) method, adds an oscillatory steering potential to the constant velocity steering potential of the FR method. This enables the calculation of the potential of mean force (PMF) in a single unidirectional oscillatory drift, rather than multiple drifts in both directions as required by the FR method. By following small forward perturbations with small reverse perturbations, the OFR method is able to generate a piecewise reverse path that follows the piecewise forward path much more closely than any practical set of paths used in the FR method. We calculate the PMF for four different systems: a dragged Brownian oscillator, a pair of atoms in a Lennard-Jones liquid, a Na(+)-Cl⁻ ion pair in an aqueous solution, and a deca-alanine molecule being stretched in an implicit solvent. In all cases, the PMF results are in good agreement with those published previously using various other methods, and, to our knowledge, we give for the first time PMFs calculated by nonequilibrium methods for the Lennard-Jones and Na(+)-Cl⁻ systems.

Strain summation in finite element modelling of multipass hot rolling

The shear strain distributions in two pass forward–forward (FF) and forward–reverse (FR) rolling have been modelled using plane strain finite element models of individual passes and then summing the results from the individual passes. This method gives excellent agreement with the average shear strain, defined by the net shear angle, and with the distribution of shear strain through the thickness, measured from the distortion of mild steel pins inserted through the thickness of experimentally rolled type 316L stainless steel slabs. The spread in breadth of the experimental slabs has little effect on the shear strain distribution or on the net equivalent strain at any position in the rolled slabs. For a given total reduction, the shear strain for FF two pass rolling is less than that for a single pass and is reduced when a smaller first pass and larger second pass reduction is applied. For FR two pass rolling, the shear strain of the first pass is essentially removed for 30%+30% reductions, but not for 50%+50% reductions. For the experimental conditions studied, the recrystallisation kinetics and recrystallised grain size produced by annealing after FF and FR two pass rolling are satisfactorily correlated by the net equivalent strain, with no evidence of any effect of the different strain paths to achieve the same value of equivalent strain.