Study of NOx removal characteristics under dielectric barrier discharge field

学位記番号:工博甲44

Rhodosporidium sp. GROWTH IN MOLASSES MEDIUM AND EXTRACTION OF ITS ASTAXANTHIN BY USING HCl

Astaxanthin is classified as a xanthophyll-carotenoid, which is red-orange colour and powerful antioxidant activity. In this study, astaxanthin was collected from Rhodosporidum sp. by pilot culture (10 liters). Molasses medium was investigated with urea ((NH4)2CO), magnesium sulfate heptahydrate (MgSO4.7H2O) and potassium dihydrogen phosphate (KH2PO4) at different concentrations. Astaxanthin was extracted by using chlorhydric acid (HCl) method.The highest dried yeast biomass was 8.3682 g/l culture supernatant and astaxathin was 1.932 g/l culture supernatant by molasses medium containing 20 g/l sugar, 0.5 g/l ((NH4)2CO, 3 g/l MgSO4.7H2O and 10 % (v/v) inoculum. HCl extraction method was mixed 10 mg biomass: 1 ml HCl 0.6 N and incubated at 70 oC, 150 minutes

Noncontact sensing systems and autonomous decision-making for early-age concrete

Early-age cracking and spalling in concrete pavements reduces slab capacity, joint load transfer, ride quality, and its long-term performance. These premature distresses lead to increased maintenance costs for sealing, patching, and grinding. Proper timing of sawcutting and curing are two construction activities that can minimize early-age distress development. In order to better time sawcutting and curing activities, an improved method to spatially monitor the setting time of concrete is required. Likewise, rapid evaluation of the joint quality after sawing is also necessary to provide feedback to adjust the timing. While previous methods for sawcutting and curing are experiential and subjective, this research aims to develop contactless sensing and computer vision techniques to significantly improve the timing of certain early-age concrete construction activity decisions through quantitative indicators. A non-contact, ultrasonic testing system (UTS) to monitor concrete set time has been developed by monitoring the evolution of leaky Rayleigh (LR-wave) wave signals over time and space (surface of the concrete). The non-contact UTS integrates a 50 kHz non-contact ultrasonic transmitter and an array of five microelectromechanical systems (MEMS) sensors as non-contact receivers. The UTS technique was first implemented in the laboratory at incident angles of 12^° for mortar mixtures in order to determine the final setting times. The UTS technique was also applied at different incident angles (12^° to 60^° ) on a mortar mixture to evaluate its influence of the angle on the UTS measurement. The final setting times for mortars were consistent with the ASTM C403 penetration resistance standard when an incident angle of 12^° was used. Additionally, this UTS was successfully field validated on three concrete pavement test sections in Illinois that had different casting times during the day. Final setting times in the field greatly varied (287 to 210 minutes) given the higher ambient temperatures and surrounding concrete mass. In order to improve decision-making on sawcut timing, the final set times measured by the UTS were linked with the earliest time to initiate sawcutting within an acceptable level of raveling. A computer vision-based (CV) process was developed that employed multiple joint images, 2D segmentation for joint raveling/spalling extraction, 3D point cloud reconstruction and meshing of the joint damage, and a 3D damage quantification analysis for assessing the joint damage. The proposed CV-based joint damage analysis quantified joint damage through two newly defined indices: (i) raveling damage index (RDI) for raveling and (ii) joint damage index (JDI) for spalling. The proposed CV-based method had an accuracy of 76% with an error of 10%. With this CV-based process, it was determined that RDI of 3% or less is an acceptable quality level for contraction joints in the field. A one-sided multi-sensor ultrasonic array device with a support vector machine algorithm was developed that detects the existence of a concealed, vertical crack beneath a notched contraction joint. This algorithm supports the field assessment of the effectiveness of sawcut timing, sawcut depth, and whether premature slab cracking was related to poor sawing procedures. The multi-sensor ultrasonic array device generated and received ultrasonic shear waves (S-wave) across the inspected joint. The acquired time domain signals were used to calculate normalized transmission energy (NTE) across the joint. The NTE algorithm defined the ratio of the energy of diffracted and reflected S-waves received behind the joint with respect to the energy of direct, diffracted, and reflected S-waves received in front of the joint. Laboratory results demonstrated that the NTE technique could successfully identify the existence or non-existence of a crack beneath the sawcut. Finally, the NTE technique coupled with a 2D decision boundary equation was field validated on 152 concrete pavement contraction joints from multiple projects with similar slab thicknesses and sawcut notch depths in Illinois and Iowa. Finally, the non-contact UTS was coupled with a 2D wavefield analysis to rapidly evaluate the effectiveness, spatially and with time, of curing methods through monitoring of the near-surface damage in hydrating paste at early-ages. The new technique monitored the energy of the LR-waves signal over time with the non-contact UTS and then, analyzed the frequency-wave number (f-k) domain to characterize the quantity of near-surface damage in the cement paste specimens. An ultrasonic surface damage index (USDI) was defined from the f-k wavefield domain based on the ratio of the non-propagating and forwarding LR-wave energy. The non-contact sensing and 2D wavefield analysis easily distinguished the differences in surface damage between the different curing methods (no curing surface, the plastic sheet cover cure, and the wax-based curing). Surfaces with low surface damage had negligible non-propagating wave energy, which was seen in the wax-based curing specimens and the unexposed bottom surfaces of all cast specimens

THE STATUS OF PARTICIPATION IN EXTRACURRICULAR SPORT TRAINING OF STUDENTS IN SOC TRANG PROVINCE, VIETNAM

The method of sociological investigation is used in the article to survey students' opinions at colleges in Soc Trang province and provided information on the status of participation in extracurricular sports of students at colleges in Soc Trang province by gender, ethnicity and purpose.  Article visualizations

THE CURRENT SITUATION OF THE INSTRUCTION IN EXTRACURRICULAR SPORTS FOR STUDENTS FROM TRA VINH UNIVERSITY, VIETNAM

This study uses the sociological investigation method and direct interview in order to understand the current situation of the instruction in extracurricular sports at Tra Vinh University. The total area of the playground is 13,700 m2 with the ratio of 1.36 m2/student. There are 11 lecturers and the ratio of student/lecturer is 915.18. There is still no regular program in extracurricular sports for Tra Vinh University students.  Article visualizations

A Robust Mobile Robot Navigation System using Neuro-Fuzzy Kalman Filtering and Optimal Fusion of Behavior-based Fuzzy Controllers

This study proposes a control system model for mobile robots navigating in unknown environments. The proposed model includes a neuro-fuzzy Extended Kalman Filter for localization task and a behaviorbased fuzzy multi-controller navigation module. The neuro-fuzzy EKF, used for estimating the robot’s position from sensor readings, is an enhanced EKF whose noise covariance matrix is progressively adjusted by a fuzzy neural network. The navigation module features a series of independently-executed fuzzy controllers, each deals with a specific navigation sub-task, or behavior, and a multi-objective optimizer to coordinate all behaviors. The membership functions of all fuzzy controllers play the roles of objective functions for the optimizer, which produces an overall Pareto-optimal control signal to drive the robot. A number of simulations and real-world experiments were conducted to evaluate the performance of this model

Stable control of networked robot subject to communication delay, packet loss, and out-of-order delivery

Stabilization control of networked robot system faces uncertain factors caused by the network. Our approach for this problem consists of two steps. First, the Lyapunov stability theory is employed to derive control laws that stabilize the non-networked robot system. Those control laws are then extended to the networked robot system by implementing a predictive filter between the sensor and controller. The filter compensates influences of the network to acquire accurate estimate of the system state and consequently ensures the convergence of the control laws. The optimality of the filter in term of minimizing the mean square error is theoretically proven. Many simulations and experiments have been conducted. The result confirmed the validity of the proposed approach