45 research outputs found
A group decision-making model for wastewater treatment plans selection based on intuitionistic fuzzy sets
As the need for environmental protection and resource sustainability has increased in recent times, wastewater treatment has become increasingly important. In this paper, a group decision-making model for plans selection in wastewater treatment is proposed. In order to deal with uncertainties and multiple attributes in wastewater treatment, an intuitionistic fuzzy set is employed to evaluate wastewater treatment plans effectively. A distance measure is defined to obtain an objective weight measuring the expert’s judgment. More specifically, experts first use group decision-making on the various plans with an intuitionistic fuzzy set. Meanwhile, Due to the decision-makers psychological behavior, the prospect theory is applied. Next, the various plans are ranked by The Order of Preference by Similarity to Ideal Solution (TOPSIS) method and prospect theory. Finally, an illustrative example of wastewater treatment plans selection is used to verify the proposed model
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Patient-Specific 3D Conformal Dose Modulator for Proton Beam Therapy
Cancer is the second leading cause of death in the United States. The probability of a person developing cancer during one’s lifetime is about 40%. It places a tremendous financial and psychological burden on people. As an external beam radiation therapy modality, proton therapy is an effective modality to fight against cancer and has gained much attention due to its unique dosimetric properties. Protocols have been developed for both passive and pencil beam scanning systems to deliver dose conformal to the tumor so that normal tissue toxicity could be mitigated. This dissertation proposes a novel inverse optimization procedure to create a patient-specific 3D conformal dose modulator paired with a corresponding fluence map for proton beam therapy. It combines the advantages of both passive and pencil beam scanning systems to deliver a conformal dose to the target using only one energy layer of the pencil beam scanning system. We first investigated the feasibility of using mini-pyramids as the fundamental structure of an energy modulation device. Then, we developed an inverse optimization algorithm to generate a 3D conformal modulator based on the intended dose distribution and basic physics principle. The robustness of the inverse algorithm was validated by Monte Carlo simulation. The physical modulator was 3D printed, and film dosimetry was performed to verify the effectiveness qualitatively. This dissertation demonstrated a robust algorithm to produce a 3D conformal dose modulator paired with a proton fluence map, inversely calculated using adaptive ring optimization techniques based on dose objectives, dose constraints, and the shape of the target. The employment of such a device can reduce the overall treatment time, thus mitigating some uncertainties while delivering dose to the target with great accuracy. </p
Photocatalytic hydrogen atom transfer-induced Arbuzov-type -C(sp3)-H phosphonylation of aliphatic amines
Despite remarkable progress in photocatalytic hydrogen atom transfer (HAT)-induced C(sp3)-H functionalization, achieving C(sp3)-H to C(sp3)-P transformation by the HAT process remains highly challenging due to P-reagents’ compatibility issues. α-Aminophosphonic acids have shown great potential in medicinal chemistry, yet their synthesis is hindered by limited substrate scopes, poor functional group tolerance, and reliance on pre-functionalized substrates, restricting their broad applications. Herein, we report a photocatalytic HAT-induced α-C(sp3)-H phosphonylation of aliphatic amines, providing rapid access to structurally diverse α-amionphosphonates from abundant amines. Leveraging intramolecular HAT, radical polar crossover, and Arbuzov-type phosphonylation cascade, the challenges associated with HAT-induced C(sp3)-H to C(sp3)-P transformation were overcome. This protocol features base-free, redox-neutral, mild conditions, broad scopes, and employing amines as limiting reagents, and allows for late-stage phosphonylation of complex drug molecules possessing amine moieties
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Conformal Dose Modulator for Proton Beam Therapy Part 1: A Simulation Study
Conformal dose deliveries in proton therapy utilize either a passive scattering system with a modulator or a pencil beam scanning (PBS) system. Efforts have been made to achieve conformal dose delivery by scanning a single energy layer of pencil beams through a 3D conformal modulator (3DCM), which combines a spread-out Bragg peak (SOBP) modulator consisting of a micro-pyramid array and a range compensator. The current published approach of designing such 3DCM relies on forward calculation methods to determine the geometry of the modulator. This study presents an alternative designing algorithm that inversely generates the geometry of a 3DCM paired with a corresponding fluence map, customized to patient-specific clinical indications.
Critical spacing governing the size and separation between neighboring micro-pyramids was first determined, under which the dose homogeneity at desired depths could be achieved. We designed an adaptive ring optimization method using a modified gradient descent algorithm to inversely calculate the geometry of the 3DCM. This method includes several stages that progressively optimize both target coverage and dose conformity. The output contains the geometry of the 3DCM and its corresponding proton fluence map. Monte Carlo (MC) simulation was used to validate the results.
The critical size and spacing of Lucite pyramids was determined to be 0.5 cm for a 184-MeV pristine proton beam. Using MATLAB (R2020a), the inverse designing algorithm generated an optimized 3DCM geometry and a fluence distribution achieving 100% target coverage with the 90% isodose surface and a corresponding conformity index of 1.057 on a spherical target. The resulting geometry was pruned to accommodate the MC simulation software and a currently accessible 3D printing service. The pruned geometry gave 95% target coverage by 90% isodose surface with a conformity index of 1.09 by ray-tracing dose computation. The MC simulation validated the 3DCM with 95% target coverage by 87% isodose surface and a conformity index of 1.12.
We have demonstrated the feasibility of using a novel inverse optimization algorithm to generate 3DCM geometry and its corresponding proton beam fluence/intensity map, which could deliver highly conformal dose distribution with pencil beam scanning system using a single energy layer
Performance analysis of the plastic square plate based on the fiber reinforced PA66
As the plastic component has the advantage of the lightweight, they are used widely in the industry and many researches are conducted simultaneously; In this study, combined the elastic constitutive model and the fiber orientation, the simulations of the plastic square plate with two material definitions are carried out. They are the orthotropic material and the anisotropic material respectively. Through the simulation comparisons, the anisotropic behaviors on the thermal field, the pressure field and the vibration characteristics of the fiber reinforced PA66 are all analyzed. The results show that the different material definitions have important influence on the structure analysis. It offers the guidance for the design and analysis of the plastic component
Optimization Design and Flexible Detection Method of a Surface Adaptation Wall-Climbing Robot with Multisensor Integration for Petrochemical Tanks
Recently, numerous wall-climbing robots have been developed for petrochemical tank maintenance. However, most of them are difficult to be widely applied due to common problems such as poor adsorption capacity, low facade adaptability, and low detection accuracy. In order to realize automatic precise detection, an innovative wall-climbing robot system was designed. Based on magnetic circuit optimization, a passive adaptive moving mechanism that can adapt to the walls of different curvatures was proposed. In order to improve detection accuracy and efficiency, a flexible detection mechanism combining with a hooke hinge that can realize passive vertical alignment was designed to meet the detection requirements. Through the analysis of mechanical models under different working conditions, a hierarchical control system was established to complete the wall thickness and film thickness detection. The results showed that the robot could move safely and stably on the facade, as well as complete automatic precise detection
Performance analysis of the plastic square plate based on the fiber reinforced PA66
As the plastic component has the advantage of the lightweight, they are used widely in the industry and many researches are conducted simultaneously; In this study, combined the elastic constitutive model and the fiber orientation, the simulations of the plastic square plate with two material definitions are carried out. They are the orthotropic material and the anisotropic material respectively. Through the simulation comparisons, the anisotropic behaviors on the thermal field, the pressure field and the vibration characteristics of the fiber reinforced PA66 are all analyzed. The results show that the different material definitions have important influence on the structure analysis. It offers the guidance for the design and analysis of the plastic component
Reliability analysis on high-pressure fuel pipe of diesel engine
High-pressure fuel pipe is an important component of the fuel injection system of diesel engine, it suffer complex loading from engine. The fatigue life of fuel pipe has great impact on reliability of engine. In this study, the fluid-solid coupling model which considers the action of fuel is established. Analysis on the effect of fuel’s pressure oscillation on the mode is carried out. Through the simulation comparisons, the mode frequency and mode shape of each model are all analysed. Base on the fluid-solid coupling model, frequency response analysis is done to study the reliability of high-pressure fuel pipe. The results show that the pressure oscillation of fuel has important influence on the mode frequency. The maximum Stress Tensor and Vibration Velocity appeared at the position of first order mode frequency. It offers the guidance for the design and analysis of High-pressure fuel pipe
Reliability analysis on high-pressure fuel pipe of diesel engine
High-pressure fuel pipe is an important component of the fuel injection system of diesel engine, it suffer complex loading from engine. The fatigue life of fuel pipe has great impact on reliability of engine. In this study, the fluid-solid coupling model which considers the action of fuel is established. Analysis on the effect of fuel’s pressure oscillation on the mode is carried out. Through the simulation comparisons, the mode frequency and mode shape of each model are all analysed. Base on the fluid-solid coupling model, frequency response analysis is done to study the reliability of high-pressure fuel pipe. The results show that the pressure oscillation of fuel has important influence on the mode frequency. The maximum Stress Tensor and Vibration Velocity appeared at the position of first order mode frequency. It offers the guidance for the design and analysis of High-pressure fuel pipe