A New Approach for Measuring Single-Cell Oxygen Consumption Rates

A novel system that has enabled the measurement of single-cell oxygen consumption rates is presented. The experimental apparatus includes a temperature controlled environmental chamber, an array of microwells etched in glass, and a lid actuator used to seal cells in the microwells. Each microwell contains an oxygen sensitive platinum phosphor sensor used to monitor the cellular metabolic rates. Custom automation software controls the digital image data collection for oxygen sensor measurements, which are analyzed using an image-processing program to yield the oxygen concentration within each microwell versus time. Two proof-of-concept experiments produced oxygen consumption rate measurements for A549 human epithelial lung cancer cells of 5.39 and 5.27 fmol/min/cell, closely matching published oxygen consumption rates for bulk A549 populations.     

基于几何可靠性机器模型的装配系统实时性能分析

装配系统是生产系统的基本结构之一, 广泛应用于汽车、电器、电子产品等实际生产环境中.与传统的串行生产线取得的研究成果相比, 装配系统的研究, 特别是对系统暂态过程的实时性能分析的研究仍然未得到深入探讨.本文针对具有三台几何可靠性机器模型和有限缓冲区容量框架下的装配系统, 首先建立了用于此类系统暂态性能分析的数学模型, 通过马尔科夫方法导出了系统性能分析的解析公式.然后, 提出了一种基于分解的性能评估算法来近似系统的实时性能.具体来说, 本文推导出了用于计算具有三台几何可靠性机器模型的装配系统的实时生产率、消耗率、在制品数量, 以及完成一个生产批次所需时间的解析表达式.最后, 通过数值实验对所提出算法的准确性进行验证.     

Modeling and control of a PEM fuel cell system: A practical study based on experimental defined component behavior

In this contribution, the dynamical behavior of a polymer electrolyte membrane (PEM) fuel cell system is modeled; related control approaches are developed. The system model used for experimental and modeling purposes describes a 1.2 kW PEM fuel cell stack and an air blower. Due to the dynamical fuel cell–blower interaction the fuel cell stack and the blower model are validated to real systems respectively. Additionally, a feedback based on PI-control is used for hydrogen pressure control with an anode inlet valve. This controller is able to eliminate a stationary error between the anode and cathode pressures. For principal investigations three control approaches, a classical static feed-forward control approach, a state-space feedback control, and a novel gain-scheduling approach are developed, applied, and compared. As result, it can be shown that the feed-forward approach lacks in performance recovering the excess oxygen ratio to the desired level. The state-space feedback control shows stationary error. The introduced gain-scheduling control approach leads to a fast excess oxygen ratio recovery without stationary deviations.     

Simultaneous determination of oxygen transport characteristics of six membranes by hexagonal dissolved oxygen sensor system

In the present study, a hexagonal sensor system composed of a six port measurement device and six different cathodes with one common anode was developed for simultaneous determination of oxygen permeabilities or diffusivities of six different membranes. To minimize experimental variations caused by geometrical differences among six individual electrodes, the current output of each electrode was divided by individual correction factors determined by standardization with a typical membrane of fluorinated ethylene propylene (FEP). The hexagonal sensor system was then used to simultaneously determine the oxygen transport characteristics such as permeabilities or diffusivities of six different polypropylene membranes. The present study showed that a newly developed hexagonal dissolved oxygen sensor system can be used for simultaneous measurement of oxygen transport characteristics of six different membranes.     

An approach to the problem of linear system identifiability through the investigation of structural properties of the connection,injection and observation matrices

The data of the linear system identificaility problem are stated, with an emphasis on the difficulties met in solving this problem by current methods, in the case of complex models.Based on the investigation of structural properties of connection, injection and observation matrices, the proposed method overcomes some of these difficulties. It leads to a necessary conditions for highly accurate identifiability, and to a necessary and sufficient condition for local identifiability.A typical application illustrates the potential of this method, although further investigations are still required, especially for making the method fully programmable.     

Control‐oriented modeling and robust nonlinear triple‐step controller design for an air‐feed system for polymer electrolyte membrane fuel cells

The efficient operation of polymer electrolyte membrane fuel cells (PEMFCs) significantly relies on the reliable control of air‐feed system. The core control objective in air‐feed system is to track a pre‐defined reference of the oxygen excess ratio to avoid oxygen starvation and stack damage. In this paper, we focus on the modeling of the air‐feed system in a PEMFC and the robust nonlinear controller design for the oxygen excess ratio tracking control. To facilitate the subsequent nonlinear controller design, a specific affine‐like, second‐order, control‐oriented model of oxygen excess ratio dynamic behavior is developed, and the modeling uncertainty is estimated and compensated by using an extended state observer (ESO). The control‐oriented model is verified via a high‐fidelity plant model. A nonlinear controller for oxygen excess ratio tracking control is proposed based on the triple‐step technique which is robust against the system disturbances. The tuning rule of the controller parameters is discussed in the scheme of the linear system. Finally, simulations are conducted to demonstrate the effectiveness and advantages of the proposed controller under variant operating conditions compared with baseline controllers.     

An AOTF-based hyperspectral imaging system for field use in ecophysiological and agricultural applications

An AOTF (Acousto-Optic Tunable Filter)-based spectral imager was developed for hyperspectral measurement of plant reflectance in the field. A hyperspectral image cube for the spectral region between 450-900 nm could be acquired at 3 to 5 nm resolution intervals within a few seconds. The system was light and compact, and both the spectral wavelengths and intervals were programmable with PC control. Wavelengths could be tuned rapidly, either sequentially or randomly. The hyperspectral image cube for rice canopies obtained by the system showed its potential in the estimation of leaf nitrogen and chlorophyll concentrations. The AOTF-based hyperspectral system would have great potential for further investigations in remote sensing of biochemical and ecophysiological plant variables.     

A simplified and generalized dynamic simulation of multi-terminal HVDC transmission system

Multi-terminal HVDC transmission systems have a large potential for applications in future power systems. One of the prime requirements of planning-stage investigations and in-operation investigations on the multi-terminal schemes is to have a simplified, dynamic model using a digital computer. One such generalized digital computer program developed, is reported here. The program includes frequency (damping) controllers, power controllers, constant current controllers, limiting nonlinearities, communication delay and central current co-ordinator it can deal with any number of converters connected in any parallel system configuration namely mesh, tapped or a combination of them both. A few case studies are included to demonstrate the ability of the program.     

烧结机漏风率在线监测系统的设计与实现

针对青岛特钢的烧结机漏风问题,基于Visual Studio 2017平台设计烧结机漏风率在线监测系统,系统在可移动的台车上和固定的风箱下部安装氧含量传感器,分别用来实现对炉篦下烟气中氧气含量和各个风箱下部烟气氧气含量的在线检测,经计算机处理得到生产过程中风箱的漏风率。系统采用接近开关获得台车上传感器的位置,针对生产现场设计了无线和有线两种信号传输方式,开发了相应的硬件和软件系统,实现各风箱漏风参数的实时检测和显示,以便工作人员及时采取降低漏风率的措施。应用表明,该系统可监测烧结过程的漏风率,对工厂的节能降耗有指导意义。     

Development of a distributed representative human model generation and analysis system (DRHM-GAS): Application to optimization of flight suit and pilot oxygen mask sizing systems

A computerized system is needed for effective determination of the sizing system of a multiple-size product. The present study developed a distributed representative human model generation and analysis system (DRHM-GAS) which can generate various sizing system candidates for a target population using different DRHM generation methods and evaluate the sizing system candidates. A five-step DRHM generation procedure (target population characterization, anthropometric variable selection, key dimension selection, grid formation, and DRHM size determination) was developed and implemented into the DRHM-GAS. A generated sizing system candidate is evaluated in the DRHM-GAS by a set of metrics including multivariate accommodation percentage and the number of sizing categories. The effectiveness of the DRHM-GAS was examined with two case studies of the development of optimal sizing systems for men's flight suit design based on the anthropometric data of US Army pilots and pilot oxygen mask design based on the facial anthropometric data of ROKAF pilots. The DRHM-GAS would be of use for product designers to establish an appropriate sizing system with efficiency.     

Development of a wrist-worn calorie monitoring system using bluetooth

Methods and tools for monitoring real-time human body information in daily life are required for advanced healthcare. In this study, a method for estimating energy expenditure during health exercises was evaluated and a wrist-worn sensing system based on the method was developed. Pulse monitoring was used to calculate energy expenditure by estimating oxygen uptake from a correlation between heart rate and oxygen uptake. Bluetooth technology was utilized for sending data by wireless communication. By the newly developed system, energy expenditure during exercise can be estimated considering individual difference and distinguishing changes in grade or load. Our goal is to construct a miniaturized wearable system that monitors vital signs and has many applications for healthcare. The study suggests that a wearable pulse sensing system proposed could provide useful information for healthcare.     

A Multicriteria Problem of Distribution of System Blood Flow among Organs and Tissues and an Algorithm for its Solution

A multicriteria mathematical model is proposed for finding the volumetric rate of blood flow in human tissues with a known volumetric system circulation rate. An algorithm is developed for decision-making as to distribution of the system blood flow among different tissues with regard for data on the oxygen consumption and carbon dioxide discharge in different tissues.     

一种用于测定氧浓度的 荧光传感器的开发及研究

基于化学发光及氧及对荧光的猝灭作用，开发了一种荧光氧传感器。考虑到气体猝灭（氧）在高分子半透膜内同时存在吸附与溶解作用，一个新的荧光猝灭动力学模型建立起来了，该方程能够很好地说明荧光猝灭的机理，并能够非常准确地拟合实验数据。     

A SOM-based data mining strategy for adaptive modelling of an offset lithographic printing process

This paper is concerned with a SOM-based data mining strategy for adaptive modelling of a slowly varying process. The aim is to follow the process in a way that makes a representative up-to-date data set of a reasonable size available at any time. The technique developed allows analysis and filtering of redundant data, detection of the need to update the process models and the core-module of the system itself and creation of process models of adaptive, data-dependent complexity. Experimental investigations performed using data from a slowly varying offset lithographic printing process have shown that the tools developed can follow the process and make the necessary adaptations of the data set and the process models. A low-process modelling error has been obtained by employing data-dependent committees for modelling the process.     

Simulation expert system for making students’ college decisions

A brief survey has been performed of foreign investigations on the modeling of the process of decision making about student choices of colleges and universities; a suitable simulation expert system has been developed at a conceptual level.     

The influence of supporting the Oxylog instrument on estimated maximal aerobic capacity during a step test and heart rate in a lifting test.

This study investigated the influence of wearing, an Oxylog mask and heart rate monitor while the Oxylog instrument was supported in a stand versus that of wearing the Oxylog mask, heart rate monitor, and the Oxylog instrument, on oxygen consumption (VO2) and heart rate response during a graduated submaximal step test protocol. Also, the predicted maximal aerobic capacities ( VO2max) produced by the two graduated step tests were compared. In addition, differences in the working heart rates in a submaximal lifting test were analyzed in two lifting tests, one with the participant wearing the Oxylog mask, heart rate monitor, and Oxylog instrument and the other required the participant to only wear a heart monitor. Seventeen experienced male manual materials handlers participated in the study, and each treatment was seen by each participant in a randomized Latin Square design. Results from the two investigations indicate that there was no significant difference in the estimated maximal oxygen consumption (p = 0.1384) and no significant difference in the heart rate between the two lift tests. The analysis did show that the 4th stage (participants reaching their physiological limits) of the step tests indicated a statistically significant difference (p = 0.0259 for oxygen consumption, and p = 0.0465 for heart rate).     

A decoupled controller for fuel cell hybrid electric power split

The power management of a hybrid system composed of a fuel cell, a battery and a DC/DC power converter is developed. A decoupled control strategy is proposed, aimed at balancing the power flow between the stack and the battery and avoiding electrochemical damage due to low oxygen concentration in the fuel cell cathode. The controller is composed of two components. The first controller regulates the compressor, and as consequence the oxygen supplied to the cathode, via a classic proportional–integral controller. The second controller optimally manages the current demanded by the fuel cell and battery via linear-quadratic control strategy acting on the converter. The closed-loop performance has been tested both in simulation and in real-time simulation using a microprocessor for the controller.     

Millisecond-order response measurement for fast oxygen gas sensors

A novel method for the evaluation of fast response of oxygen gas sensors in terms of milliseconds is developed. Using the method of modulating oxygen partial pressure by changing the total pressure inside the test chamber, the millisecond-order measurement was succeeded. For the 100 Hz sign-wave operation, the measurement system generated the pressure changes from 180 to 220 kPa, corresponding to the change of oxygen partial pressure from 36 to 44 kPa. Using both jump-method and pressure modulation method, the response of the resistive oxygen sensors of cerium oxide thick films were evaluated at 1173 K and the kinetic mechanism of gas sensing was discussed. Their response times of t₉₀ obtained by square-wave change were measured to be 37 and 22 ms for high-to-low oxygen partial pressure and vice versa transition, respectively. The log–log plot of resistance of sensor and the frequency, pressure modulation spectra, was also evaluated at the same time and the kinetics of oxygen sensing was suggested to be diffusion-limited.     

Fuzzy state machines to recognize totally unconstructed handwritten strokes

An automatic off-line character recognition system for totally unconstrained handwritten strokes is presented. A stroke representation is developed and described using five types of feature. Fuzzy state machines are defined to work as recognizers of strokes. An algorithm to obtain a deterministic fuzzy state machine from a stroke representation, that is capable of recognizing that stroke and its variants is presented. An algorithm is developed to merge two fuzzy state machines into one machine. The use of fuzzy machines to recognize strokes is clarified through a recognition algorithm. The learning algorithm is a complex of the previous algorithms. A set of 20 stroke classes was used in the learning and recognition stages. The system was trained on 5890 unnormalized strokes written by five writers. The learning stage produced a fuzzy state machine of 2705 states and 8640 arcs. A total of 6865 unnormalized strokes, written freely by five writers other than the writers of the learning stage, was used in testing. The recognition, rejection and error rates were 94.8%, 1.2% and 4.0%, respectively. The system can be more developed to deal with cursive handwriting.