Automated manufacturability analysis: A survey

In the market-place of the 21st century, there is no place for traditional over-the-wall communications between design and manufacturing. In order to design it right the very first time, designers must ensure that their products are both functional and easy to manufacture. Software tools have had some successes in reducing the barriers between design and manufacturing. Manufacturability analysis systems are emerging as one such tool — enabling identification of potential manufacturing problems during the design phase and providing suggestions to designers on how to eliminate them.In this paper, we provide a survey of current state-of-the-art automated manufacturability analysis. We present the historical context in which this area has emerged and outline characteristics to compare and classify various systems. We describe the two dominant approaches to automated manufacturability analysis and overview representative systems based on their application domain. We describe support tools that enhance the effectiveness of manufacturability analysis systems. Finally, we attempt to expose some of the existing research challenges and future directions.     

Automated photoelastic analysis

Photoelastic stress analysis can be a long and tedious process. However recent and current developments in the field of automated and computer aided photoelastic analysis mean that it is becoming possible to do more complex analysis and to perform it more quickly. This paper provides a survey of these developments and the advances in polariscope design.     

气体微流量测量技术的发展

本文介绍了美国NIST、德国PTB、日本NMIJ、意大利IMGC、韩国KRISS、中国计量科学研究院NIM和国防科技工业真空一级计量站(兰州物理研究所LIP)的气体微流量测量技术的研究进展,并对其测量方法,测量装置性能指标进行了评述。     

Automated system for noise-measurements on low-ohmic samples andmagnetic sensors

An automated system for electronic noise measurements on metal films is presented. This new system, controlled by a personal computer which utilizes National Instruments' LabVIEW software, is designed to measure low frequency noise as a function of an externally imposed magnetic field and as a function of a dc bias current in low-ohmic samples and magnetic sensors. With this system we are able to measure continuously for several days, during which the measured spectra are collected, processed and stored for further analysis     

Automated electrochemical free radical scavenger screening in dietary samples

An automated electrochemical microtiter plate assay for the quantification of free radical scavengers (antioxidants) in food samples is described. Dietary antioxidant capacity measurements were achieved using the radical compound 2,2-diphenyl-1-picrylhydrazyl (DPPH·) as an amperometric redox indicator, with a pencil lead working electrode, in conjunction with a Pt counter-electrode and Ag/AgCl reference electrode, moving sequentially through the 24 vials of a standard 6 × 4 microtiter plate. Programmed analyses were performed successfully with synthetic antioxidants of known concentrations and with tea infusions, fruit juices, and vegetable extracts. The novel methodology is simple and convenient as, unlike common DPPH· antioxidant electroanalysis, it avoids the time-consuming cleaning of electrochemical cells between measurements. Microtiter plate-based robotic electrochemical antioxidant assaying is thus a good option for handling large sample collections and may be applicable in the production of food and herbal remedies.     

Development of an 19F NMR method for the analysis of fluorinated acids in environmental water samples

This investigation was carried out to evaluate 19F NMR as an analytical tool for the measurement of trifluoroacetic acid (TFA) and other fluorinated acids in the aquatic environment. A method based upon strong anionic exchange (SAX) chromatography was also optimized for the concentration of the fluoro acids prior to NMR analysis. Extraction of the analyte from the SAX column was carried out directly in the NMR solvent in the presence of the strong organic base, DBU. The method allowed the analysis of the acid without any prior cleanup steps being involved. Optimal NMR sensitivity based upon T1 relaxation times was investigated for seven fluorinated compounds in four different NMR solvents. The use of the relaxation agent chromium acetylacetonate, Cr(acac)3, within these solvent systems was also evaluated. Results show that the optimal NMR solvent differs for each fluorinated analyte. Cr(acac)3 was shown to have pronounced effects on the limits of detection of the analyte. Generally, the optimal sensitivity condition appears to be methanol-d4/2M DBU in the presence of 4 mg/mL of Cr-(acac)3. The method was validated through spike and recovery for five fluoro acids from environmentally relevant waters. Results are presented for the analysis of TFA in Toronto rainwater, which ranged from < 16 to 850 ng/L. The NMR results were confirmed by GC-MS selected-ion monitoring of the fluoroanalide derivative.     

NMR of room temperature samples with a flux-locked dc SQUID

Superconducting quantum interference devices (SQUIDs) are the most sensitive detectors of magnetic fields. Since SQUIDs detect the magnetic flux rather than its rate of change, they can be used to great advantage to measure nuclear magnetic resonance (NMR) signals at low fields and frequencies. We have used a dc (direct-current) SQUID operated in flux-locked mode to significantly improve upon our previous low-field NMR results performed using an RF (radio-frequency) SQUID. The increase in sensitivity gained by using the dc SQUID has helped in reducing the signal acquisition time by a factor of more than 100 compared with our earlier measurements using an RP SQUID. We have also obtained a simple one-dimensional T₁-contrasted NMR image of a two-component sample consisting of mineral oil and tap water at room temperature. Our results highlight the sensitivity of the SQUID as an NMR detector and the promise of using SQUIDs in NMR imaging at low fields for both medical applications and for materials' nondestructive evaluation     

Automated FE analysis of flange assemblies

An automated finite element computer program to analyse bolted circular weld neck flange and gasket assemblies has been developed. The program is based on an extensive database of British, European and American flange and gasket standards. The program is ideal for identifying problem areas and conducting sensitivity studies.     

Automated analysis of chemical reaction data

The paper describes a combined automated and computational approach to the analysis of chemical reaction data and estimation of the rate constant. Analog data, sampled and digitised, are subjected to a real-time analysis which avoids the need for an often unreliable infinity reading and allows the reaction to be terminated in the early stages. For the test reaction, the hydrolysis of sucrose, the rate constant is estimated more accurately and about seven times more rapidly than is possible by the conventional, off-line method.     

Automated instrument for ultrasonic structural analysis

An instrument for measuring the velocity of bulk acoustic waves in solids is described. A small measurement error (∼0.05%) is achieved by implementing a phase technique. Microprocessor-based automation shortens the time for one measurement to 3–5 sec. The instrument can be used for the quality control of solid materials (glass, ceramics, crystals, etc.) in a mass-production environment. Translated from Izmeritel'naya Tekhnika, No. 7, pp. 57–58, July, 1995     

Automated hazard analysis of digital control systems

Digital instrumentation and control (I&C) systems can provide important benefits in many safety-critical applications, but they can also introduce potential new failure modes that can affect safety. Unlike electro-mechanical systems, whose failure modes are fairly well understood and which can often be built to fail in a particular way, software errors are very unpredictable. There is virtually no nontrivial software that will function as expected under all conditions. Consequently, there is a great deal of concern about whether there is a sufficient basis on which to resolve questions about safety. In this paper, an approach for validating the safety requirements of digital I&C systems is developed which uses the Dynamic Flowgraph Methodology to conduct automated hazard analyses. The prime implicants of these analyses can be used to identify unknown system hazards, prioritize the disposition of known system hazards, and guide lower-level design decisions to either eliminate or mitigate known hazards. In a case study involving a space-based reactor control system, the method succeeded in identifying an unknown failure mechanism.     

Analysis of multiple samples using multiplex sample NMR: selective excitation and chemical shift imaging approaches

Two improved approaches for the rapid analysis of multiple samples using multiplex sample NMR are described. In the first approach, frequency-selective 90 degrees radio frequency pulses and large pulsed field gradients are applied to excite and detect multiple samples in rapid succession. This method is advantageous for samples with relatively long longitudinal (T1) relaxation times. In the second approach, chemical shift imaging is applied to acquire both the spectral and spatial information of multiple samples simultaneously. Chemical shift imaging is more time-consuming than selective excitation; however, it is advantageous for detecting samples with short T1's and for signal averaging. Both approaches demonstrate the potential of multiplex sample NMR for carrying out high-throughput NMR detection.     

Computerised glow curve analysis: a tool for routine thermoluminescence dosimetry

The basic features of computerised glow curve analysis methods are presented, together with the advantages derived from their use for dosimetry. The rapid development of personal computers with progressively greater computation capability has permitted the application of different analysis methods for practical dosimetry. A very simple glow curve analysis method, specifically developed for the measurement of low or very low doses usually measured in personal and environmental dosimetry, is also discussed.     

Distributed microflow sensor arrays and networks: design of architectures and communication protocols

Distributed microflow sensor arrays and networks are built from collections of spatially scattered, intelligent microflow sensor nodes. They can enhance the reliability and fault tolerance of the system. A new cluster network architecture and two original alternatives of fault-tolerant time-out communication protocol are described. Teamwork integration evaluator/micro-electromechanical system, a micro-electromechanical system sensor network simulation tool, was developed to evaluate the effectiveness of the network architectures and communication protocols.