Optimal Synthesis Method Research Articles

EXPERIMENTAL INVESTIGATION OF SMOOTH MATCHING TRANSITIONS BASED ON MICROSTRIP TRANSMISSION LINE HETEROGENEOUS SECTIONS

An experimental investigation of smooth matching transitions based on inhomogeneous sections of a microstrip transmission line with different wave impedances profiles was carried out in the present work. Comparative tests of smooth matching transitions prototypes are presented in order to confirm the theoretical data obtained by the optimal parametric synthesis method. The possibility of using synthesized piecewise linear transition to ensure good coordination in a fairly wide frequency range has been proven. It has been shown that fabricated inhomogeneous microstrip waveguide transitions provide matching in the frequency range from 1.2 to 2.7 GHz. It has been proven that the use of two-stage transitions allows a 1.5-times increase in the frequency matching band. Locally-optimized matching transitions near the lower boundary of the operating frequency range can give a significant gain in comparison with matching transitions with an exponential wave impedance profile for the same electrical length. The developed matching transitions can be used in the design of filters, matching transformers and connecting elements of the microwave frequencies transmission line.

Synthesis and luminescence properties of β-NaRE0.95Eu0.05F4 (RE[dbnd]Y, Lu)

On the base of β-NaYF4 and β-NaLuF4 compounds, optimal synthesis methods were selected to obtain highly crystalline Eu3+-doped compounds in the hexagonal (β) structure. The compounds β-NaY0.95Eu0.05F4 and β-NaLu0.95Eu0.05F4 were synthesized by hydrothermal synthesis. The concentration of Na2EDTA introduced into the reaction system as a modifier affects the shape and size of the product from elongated hexagonal prisms to quartz-like crystals. The thermal behavior of the compounds has been studied; the temperature of the polymorphic transition from hexagonal to cubic structure is 680°C for β-NaY0.95Eu0.05F4 and 624°C for β-NaY0.95Eu0.05F4, the melting point of α-NaRE0.95Eu0.05F4 is about 900°C. Under excitation with UV-light of λ = 393nm, β-NaY0.95Eu0.05F4 and β-NaLu0.95Eu0.05F4 show the emission lines of direct Eu3+f-f transitions, with the presence of the emission from higher Eu3+ excited states (up to 5H3) in both samples, which is responsible for the more orange color of emission instead of the usual red for Eu3+. Emission decay times are slightly longer for β-NaY0.95Eu0.05F4 than for β-NaLu0.95Eu0.05F4, which is the result of a bigger unit cell for the former, leading to longer interatomic distances between Eu3+ ions in the lattice. The luminescence mechanisms for the doped lanthanide ions were thoroughly analyzed.

Optimal heat exchanger network synthesis by sequential splitting of process streams

The paper introduces a new iterative sequential method for optimal heat exchanger network synthesis, that relies on an assignment problem. This method considers the splitting of hot and cold process streams, and uses a decomposition that fixes the split fractions for process streams at each subproblem. We apply this method to several heat integration problems to demonstrate its performance and efficiency. It is also compared with stage-wise superstructure optimization using mixed-integer nonlinear programming.

Photonic Crystals for Plasmonic Photocatalysis

Noble metal (NM)-modified wide-bandgap semiconductors with activity under visible light (Vis) irradiation, due to localized surface plasmon resonance (LSPR), known as plasmonic photocatalysts, have been intensively studied over the last few years. Despite the novelty of the topic, a large number of reports have already been published, discussing the optimal properties, synthesis methods and mechanism clarification. It has been proposed that both efficient light harvesting and charge carriers’ migration are detrimental for high and stable activity under Vis irradiation. Accordingly, photonic crystals (PCs) with photonic bandgap (PBG) and slow photon effects seem to be highly attractive for efficient use of incident photons. Therefore, the study on PCs-based plasmonic photocatalysts has been conducted, mainly on titania inverse opal (IO) modified with nanoparticles (NPs) of NM. Although, the research is quite new and only several reports have been published, it might be concluded that the matching between LSPR and PBG (especially at red edge) by tuning of NMNPs size and IO-void diameter, respectively, is the most crucial for the photocatalytic activity.

Electrochemical Synthesis of an Organometallic Material Based on Polypyrrole/MnO2 as High-Performance Cathode

We report herein the design of promising composite material as a cathode in a rechargeable battery by combining the properties of polypyrrole (PPy) and MnO2 particles. The composites were prepared by electropolymerization of the pyrrole monomer followed by electrodeposition of a manganese salt suspension by two methods. The first method involved the formation of MnO2 in situ in the PPy/ITO electrode, while the second method involved first a preliminary adsorption of Mn2+ ions in the polymer, followed by an electrochemical of the electrode. The morphology of the resulting composite materials (PPy/MnO2) was studied by energy-dispersive X-ray spectroscopy (EDS), X-ray diffractometry (XRD), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR). The investigations of the electrochemical properties of the composite electrodes show that the presence of MnO2 play an important role in improving the surface of polymer films, which leads to lower charge transfer resistance and higher electrode activity. For the optimal synthesis method, the electrode generates a maximum current of up to − 7.9 mA cm−2 for the oxygen reduction reaction, which is eight times the current density delivered by the electrode without PPy.

Engineered/designer hierarchical porous carbon materials for organic pollutant removal from water and wastewater: A critical review

Hierarchical porous carbon (HPC) materials have found advanced applications in energy storage, adsorption, and catalysis in recent years. The HPC can be synthesized from a vast range of inexpensive carbon precursors, and contain unique structural features, such as nano-scale dimension, high porosity, high surface area, and tunable pore surfaces. These materials hold immense potential for removing contaminants from water and wastewater. However, this area is severely under-explored yet. In this review, we have discussed the recent advances of synthesis, modification, and application of HPC for the removal of pollutants from water, especially focusing on organic pollutants. Owing to their intrinsic hydrophobic nature and unique interconnected porous structure, HPC demonstrates a high affinity to hydrophobic organic contaminants, which can be enhanced many folds by target-specific chemical activation. Successful high-performance removal of contaminants by pristine and modified HPC includes plastic-derived (e.g. bisphenol A), pharmaceutical (e.g. antibiotics), dye (e.g. methylene blue) and pesticide micro-pollutants. Future research is warranted to find optimal and effective HPC synthesis and modification methods for further improving their ability to remove aqueous organic contaminants as a low-cost and energy-inexpensive remediation technology.

STyLuS*: A Temporal Logic Optimal Control Synthesis Algorithm for Large-Scale Multi-Robot Systems

This article proposes a new highly scalable and asymptotically optimal control synthesis algorithm from linear temporal logic specifications, called for large-Scale optimal Temporal Logic Synthesis, that is designed to solve complex temporal planning problems in large-scale multi-robot systems. Existing planning approaches with temporal logic specifications rely on graph search techniques applied to a product automaton constructed among the robots. In our previous work, we have proposed a more tractable sampling-based algorithm that builds incrementally trees that approximate the state space and transitions of the synchronous product automaton and does not require sophisticated graph search techniques. Here, we extend our previous work by introducing bias in the sampling process that is guided by transitions in the Büchi automaton that belong to the shortest path to the accepting states. This allows us to synthesize optimal motion plans from product automata with hundreds of orders of magnitude more states than those that existing optimal control synthesis methods or off-the-shelf model checkers can manipulate. We show that is probabilistically complete and asymptotically optimal and has exponential convergence rate. This is the first time that convergence rate results are provided for sampling-based optimal control synthesis methods. We provide simulation results that show that can synthesize optimal motion plans for very large multi-robot systems, which is impossible using state-of-the-art methods.

Polyol Silver Nanowire Synthesis and the Outlook for a Green Process

Silver nanowires (AgNWs) have a broad range of applications including nanoelectronics, energy conversion, health care, solar cells, touch screens, sensors and biosensors, wearable electronics, and drug delivery systems. As their characteristics depend strongly on their size and morphology, it is essential to find the optimal and most cost-effective synthesis method with precise control over the size and morphology of the wires. Various methods for AgNW synthesis have been reported along with process optimization and novel techniques to increase the yield and aspect ratios of synthesized AgNWs. The most promising processes for synthesis of AgNWs are wet chemical techniques, in which the polyol process is low cost and simple and provides high yield compared to other chemical methods. Reaction mechanism is one of the most important factors in strategies to control the process. Our purpose here is to provide an overview on the main findings regarding synthesis, preparation, and characterization of AgNWs. Recent efforts in the polyol synthesis of AgNWs are summarized with respect to product morphology and size, reaction conditions, and characterization techniques. The effect of essential factors such as reagent concentration and preparation, temperature, and reaction atmosphere that control the size, morphology, and yield of synthesized AgNWs is reviewed. Moreover, a review on the novel modified polyol process and reactor design such as continuous millifluidic and flow reactors to increase the yield of synthesized AgNWs on large scales is provided. The most recent proposed growth mechanisms and kinetics behind the polyol process are addressed. Finally, comparatively few available studies in green and sustainable development of 1D silver nanostructures through the application of natural products with inherent growth termination, stabilization, and capping characteristics are reviewed to provide an avenue to natural synthesis pathways to AgNWs. Future directions in both chemical and green synthesis approaches of AgNWs are addressed.

Modeling and Dynamic Response Analysis of a Compound Power-Split Hybrid Electric Vehicle During the Engine Starting Process

This study is aimed at revealing the dynamic response characteristics of a power-split hybrid electric vehicle (HEV) during the mode transition process with the engine starting. In this paper, for a hybrid powertrain system whose engine is directly connected to a compound power-split transmission, the equivalent lever method is first used to analyze the mode transition process with the engine starting. Then, based on the theoretical formulations and lookup tables, a dynamic model of the compound power-split HEV is established in detail, taking into consideration the engine ripple torque, battery-motor characteristics, dynamic meshing force between gears, and shaft spring-damping characteristics. The powertrain dynamic model is verified by a bench test. Moreover, taking the vehicle jerk and engine starting time as the evaluation indexes of the dynamic response characteristics, the influencing factors of the dynamic response characteristics in the engine starting process are analyzed comprehensively from the aspects of the engine, battery-motor, and engine starting condition. Finally, the engine starting process is synthetically optimized based on the obtained impact law of different influencing factors. The simulation results show that the synthesis optimization method can effectively reduce vehicle jerks and the engine starting time and improve driving comfort during the engine starting process.

Expansion of the domain of existence of the cylindrical involute gears

The method for optimal geometric synthesis of gearing of cylindrical involute gears is proposed in this paper. A new geometry settlements system has been proposed. The technique developed on the basis of this settlements system can significantly expand the domain of existence of the solution to the synthesis problem, as well as the domain of existence of gear.

The optimization method for synthesis of technetium-99m-luteolin as radiotracer in the development of cancer drugs from flavonoid.

The aim of this study is to find the optimum conditions of labeling luteolin flavonoid compounds with technetium-99m (99mTc) to meet the purity requirements stated in the United States Pharmacopeia. This compound is expected to be a potential radiotracer compound for diagnosing cancer. The optimization method in labeling luteolin with technetium determines the parameters such as pH, SnCl2.2H2O, genistein concentration, and incubation time. Optimization results of Technetium-99m-luteolin labeling obtained optimum pH conditions 8, the amount of SnCl2.2H2O as a reducing agent 60 μL, the optimum amount of luteolin 6 mg/ml, and the optimum incubation time is 30 min. This optimum condition obtained a 99mTc-Luteolin radiochemical purity yield of 94.15%. The radiochemical purity percentage of the 99mTc-Luteolin compound has fulfilled the requirements listed at United States Pharmacopeia, which is ≥90%.

An efficient basic heterogeneous catalyst synthesis of magnetic mesoporous Fe@C support SrO for transesterification

To achieve the green production of biodiesel, in this study, a novel magnetic mesoporous support (Fe@C) was obtained from MIL–Fe(100) carbonization. Strontium oxide (SrO) was then loaded on Fe@C to synthesize the sufficient, easy separable and environmentally friendly heterogeneous basic catalyst (Fe@C–Sr) for transesterification on the purpose of biodiesel production. In order to obtain the optimal synthesis method, effects of the activation temperature and SrO loading amount on catalytic activity were evaluated. In addition, Fe@C and Fe@C–Sr were characterized by means of X–ray diffraction (XRD), N2 adsorption–desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectra (FTIR), Hammett indicator method, vibrating sample magnetometer (VSM), and X–ray photoelectron spectroscopy (XPS). To assess the catalytic behavior of Fe@C–Sr, transesterification parameters of catalyst amount, molar ratio of methanol to oil, reaction time, and reaction temperature were investigated and optimized. Meanwhile, based on the optimal transesterification parameters, the reusability and resistant ability to free fatty acid and free water were further concerned to explore the catalyst stability.

Design and development of vibratory cultivator using optimization algorithms

Tillage system design is one of the important areas of interest for farming community. Oscillatory tillage is one such area which reduces the draft consumption and plays a crucial role to farmers during soil manipulation process. The paper deals to design a vibratory mechanism to provide a continuous motion to the tillage tool for following a particular path adopted from the literature through proper synthesis theory and procedure. A four bar mechanism is designed through proper synthesis procedure to identify the dimensions. Analytical and optimal synthesis method is followed during the design process. Optimization algorithms such as hybrid teaching–learning particle swarm optimization based algorithm (HTLPSO), teaching–learning based algorithm, and particle swarm optimization is used to find the values of the design variables. MATLAB is the software used for the synthesis and analysis process. It is observed in the study that designed four mechanism follows the required path for vibratory tillage operation. The results attained through optimization algorithm in HTLPSO performed better for the required path than other nature-inspired algorithms. Also the developed vibratory cultivator performed better in the field trials.

Imaging the Pore Structure in Geomaterials Using Rhodamine B Covalently Decorated Magnetic Nanoparticles

There has been a recent booming development of multifunctional nanoparticles with precisely defined materials and an accompanying abundance of synthesis methods. However, developing a rational strategy to choose the proper nanoparticle and optimal synthesis method for geological applications remains a bottleneck. Here, a rhodamine B covalently decorated Fe3O4 nanoparticle was studied to assess its application as a novel bifunctional nanomarker for the optical imaging of the pore structure in geomaterials. With this bifunctional nanomarker, we were able to combine magnetic injection, which provides a simple and non-destructive way of introducing the nanomarker into rocks, with fluorescence imaging techniques, which provide clear contrast imaging between geomaterials (black) and porosity (bright). The covalent bifunctional nanomarker exhibits higher fluorescence and less leakage of the fluorescence dye than those produced by the physical coating method. It offers not only a more practical and reliable nanomarker for the analysis of the pore structure in geomaterials but also contributes to nanomaterial-oriented research for various geological applications.

Investigation of Metal-Organic Framework-5 (MOF-5) as an Antitumor Drug Oridonin Sustained Release Carrier.

Oridonin (ORI) is a natural active ingredient with strong anticancer activity. But its clinical use is restricted due to its poor water solubility, short half-life, and low bioavailability. The aim of this study is to utilize the metal organic framework material MOF-5 to load ORI in order to improve its release characteristics and bioavailability. Herein, MOF-5 was synthesized by the solvothermal method and direct addition method, and characterized by Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Fourier Transform Infrared Spectrometer (FTIR), Thermogravimetric Analysis (TG), Brunauer–Emmett–Teller (BET), and Dynamic Light Scattering (DLS), respectively. MOF-5 prepared by the optimal synthesis method was selected for drug-loading and in vitro release experiments. HepG2 cells were model cells. MTT assay, 4′,6-diamidino-2-phenylindole (DAPI) staining and Annexin V/PI assay were used to detect the biological safety of blank carriers and the anticancer activity of drug-loaded materials. The results showed that nano-MOF-5 prepared by the direct addition method had complete structure, uniform size and good biocompatibility, and was suitable as an ORI carrier. The drug loading of ORI@MOF-5 was 52.86% ± 0.59%. The sustained release effect was reliable, and the cumulative release rate was about 87% in 60 h. ORI@MOF-5 had significant cytotoxicity (IC50:22.99 μg/mL) and apoptosis effect on HepG2 cells. ORI@MOF-5 is hopeful to become a new anticancer sustained release preparation. MOF-5 has significant potential as a drug carrier material.

Optimal synthesis of pose repeatability for collaborative robots based on the ISO 9283 standard

PurposeThe purpose of this paper is to search the optimal arrangement scheme of random motion accuracy of joints for optimal synthesis of pose repeatability which can make robot design more reasonable and reduce the development cost of robots.Design/methodology/approachIn this paper, a mathematical model of pose repeatability, which includes positioning repeatability and orientation repeatability of robots, is established. According to the ISO 9283 standard, an optimal synthesis method of pose repeatability for collaborative robots is introduced, and three optimization objective functions are proposed. The optimization model is solved by using numerical analysis software, and the optimal arrangement scheme of random motion accuracy of joints is obtained which meets the requirements of pose repeatability of robot.FindingsIt is found that, in three optimization objective functions, the single-objective evaluation function of maximization of joint motion error is more suitable for optimal synthesis of pose repeatability. In practice, due to the safety factor, the test results of pose repeatability are better than the results of optimal synthesis of pose repeatability.Practical implicationsThis method makes robot design more reasonable and reduces the development cost of robots.Originality/valueThis work is the first time to optimize the orientation repeatability of collaborative robots. Because the pose repeatability of most robots is tested by the ISO 9283 standard, so this method which is based on this standard is more suitable for the performance requirements of robot products.

NGHIÊN CỨU TỔNG HỢP LUẬT DẪN GIAI ĐOẠN QUÁN TÍNH CHO TÊN LỬA KHÔNG ĐỐI KHÔNG TẦM TRUNG

The paper presents a method of optimal guidance law synthesis for medium range air-to-air missile using information from the inertial system (inertial phase). During this phase, missile is brought to the predicted interception point. Requirement at the end of inertial phase: Distance and rotation angle speed of line of sight missile-target to ensure favorable for open homing head. Quality of guidance law is evaluated according to three parameters: Response overload, rotation angle speed of line of sight, and instant sliding. At the end of inertial phase, simulation results for three parameters of new guidance law are smaller (quality of guidance law is better) than that of proportional navigation law.

Near‐Infrared‐Emitting Five‐Monolayer Thick Copper‐Doped CdSe Nanoplatelets

AbstractDoped nanocrystals are instrumental to the high‐performance luminescent solar concentrators (LSCs) and the color conversion devices. Recently, copper (Cu)‐doped three and four monolayer (ML) thick CdSe nanoplatelets (NPLs) have been shown superior to the existing Cu‐doped quantum dots (QDs) for their use in LSCs. However, additional improvement in the LSC performance can be achieved by further redshifting the emission into the near‐infrared (NIR) region of electromagnetic spectrum and increasing the absorbed portion of the solar irradiation. Cu‐doping into higher thicknesses of these atomically flat NPLs (e.g., ≥5 ML) can achieve these overarching goals. However, addition of the dopant ions during the nucleation stage disturbs this high‐temperature growth process and leads to multiple populations of NPLs and QDs. Here, by carefully controlling the precursor chemistry the successful doping of Cu in five ML thick NPLs by high‐temperature nucleation doping method is demonstrated. The optimized synthesis method shows nearly pure population of doped five ML thick NPLs, which possess ≈150 nm Stokes‐shifted NIR emission with high quantum yield of 65 ± 2%. Structural, elemental, and optical studies are conducted to confirm the successful doping and understand the detailed photophysics. Finally, these materials are tested experimentally and theoretically for their performance as promising LSC materials.

Geometrical synthesis of four-bar gear train with related gears

The method of optimal geometric synthesis of four-bar cylindrical gear with related gears with one external and one internal gearing is proposed. The method is based on a new calculation system that increases the number of synthesis output parameters to six, which makes it possible to considerably expand the domain of existence of the synthesis problem solution with the simultaneous synthesis of two gearing. The software implementing the proposed technique is described. To solve the problem of nonlinear mathematical programming the library of Optimization Toolbox functions included in Matlab is used. Examples of calculations are given.

The Optimization Method for Synthesis of 99mTc-Rutin as Potential Radiotracer in The Development of Cancer Drugs From Flavonoid

Based on the Basic Health Research Data of Ministry of Health's of Indonesia in 2013, mortality rates from malignant and tumor malignancies in Indonesia are still high with prevalence of cancer is about 1.4%. Chemotherapy is still the primary choice in cancer modality that uses chemotherapeutic drugs to eradicate and inhibit the growth of cancer cells; however the cost this treatment is extremely high. Therefore, patient tends to seek alternative treatment such as consuming traditional herbal medicine for cancer treatment. Rutin is one of the attractive phytochemicals flavonoids because of its antioxidant activities. However, as traditional herbal medicine, its effectiveness is not yet been fully established due to the lack of scientific information. A radiotracer can be defined as a specific radiolabeled molecule that monitors the in vivo behaviour of a functional molecule, and can be used to provide biological information in a living system. Hence, to provide pharmacological information of rutin for cancer treatment, we synthesized radiolabeled flavonoid 99mTc-rutin as radiotracer. The aim of the present study is to develop 99mTc-rutin under varying conditions of rutin quantity, reducing agent concentration and incubation time. Labeling studies were performed by changing the selected parameters one by one and optimum labeling conditions were determined. After observing the conditions for maximum labeling efficiency, 99mTc-rutin was obtained with preparation of 700 μg of rutin with addition of 20 μg of SnCl2.2H2O as reductor and 1-3 mCi 99mTcO4- without any incubation. Radiochemical yield of 99mTc-rutin was determined with radio thin layer chromatography which was found 99.28 ± 0.14% and stable up to 4 hour. From the result of this study, the successfully labeled 99mTc-rutin can be used as a reference for following preclinical study. Furthermore radiolabeled 99mTc-rutin is expected as tools in research and development of rutin as cancer drugs from natural product to obtain detailed information its efficacy.Keywords: radiotracer, 99mTc-rutin, cancer, labeled compounds