Photoacoustic Leak Testing

2000 ◽  
Author(s):  
Serdar H. Yönak ◽  
David R. Dowling

Abstract Leak testing is a critical manufacturing quality control process. Unintended leaks in pressurized or evacuated containers may be detrimental to consumers, manufacturers, and/or the environment. This paper describes a leak detection and localization technique based on photoacoustic sounds produced by scanning a carbon dioxide laser over leaks emitting a photoactive tracer gas, sulfur hexaflouride. Photoacoustic signals are recorded in a bandwidth from 3 up to 110 kHz by multiple microphones. From these recorded signals, the presence or absence of a leak may be deduced by comparison with background noise levels. When a leak is present, its location is determined from a simple model of the acoustic environment and matched field processing (MFP). Current results show that a gas leak of 1 cm3 per day can be detected and localized to within ±1 mm in a few seconds using four microphones placed 0.41 m from the leak location and an incoherent average of the MFP ambiguity surfaces at twelve signal frequencies.

2021 ◽  
pp. 1-11
Author(s):  
Song Gang ◽  
Wang Xiaoming ◽  
Wu Junfeng ◽  
Li Shufang ◽  
Liu Zhuowen ◽  
...  

In view of the production quality management of filter rods in the manufacturing and execution process of cigarette enterprises, this paper analyzes the necessity of implementing the manufacturing execution system (MES) in the production process of filter rods. In this paper, the filter rod quality system of cigarette enterprise based on MES is fully studied, and the constructive information management system demand analysis, cigarette quality control process, system function module design, implementation and test effect are given. This paper utilizes the Fuzzy analytic hierarchy process to find the optimal system for processing the manufacturing of cigarette. The implementation of MSE based filter rod quality information management system for a cigarette enterprise ensures the quality control in the cigarette production process. Through visualization, real-time and dynamic way, the information management of cigarette production is completed, which greatly improves the quality of cigarette enterprise manufacturing process.


Cell ◽  
2021 ◽  
Vol 184 (11) ◽  
pp. 2896-2910.e13
Author(s):  
Haifeng Jiao ◽  
Dong Jiang ◽  
Xiaoyu Hu ◽  
Wanqing Du ◽  
Liangliang Ji ◽  
...  

2018 ◽  
Vol 22 (2) ◽  
pp. 222-231
Author(s):  
V.S. Pai

Maggi was the most popular instant noodles brand in India, which children in particular loved to snack on. The brand had a dominant position until suddenly in mid-2015 it got engulfed in controversy. Several state food regulators found that Maggi contained monosodium glutamate as well as lead well above the prescribed limits. Both these substances were harmful especially for children. When Nestlé India was confronted with lab test results it stuck to its position that they had a world class quality control process in place and that their products were safe for consumption. Finally, the national food regulator FSSAI, ordered a ban on the sale of Maggi including product recall. Consequently, several state governments imposed temporary ban on the sale of Maggi noodles in their respective states. The future of the company suddenly looked very bleak. Nestlé India was slow to respond to this fast unfolding crisis. Further, their responses were very brief and not adequately culture-sensitive. This led to the feeling in several quarters that the company was probably guilty of wrongdoing. To set right things Nestlé's worldwide CEO flew into India to douse the flames of the controversy and draw up an appropriate strategy to bail out the brand. He address the media, put in place a new CEO for Nestlé India and set brand Maggi on the path of recovery. However, Nestlé India was still facing a number of critical issues. What should be done to win over the trust of its customers? How should it recover market share lost to competitors both old rivals and new entrants? What strategy should it develop to succeed with the new products, especially hot heads, launched along with the comeback strategy? Should it change its approach to dealing with government health officials to prevent confrontations in future? How should it shorten the response time and make it effective in the face of a media backed public outcry in future?


2013 ◽  
Vol 141 (2) ◽  
pp. 798-808 ◽  
Author(s):  
Zhifang Xu ◽  
Yi Wang ◽  
Guangzhou Fan

Abstract The relatively smooth terrain embedded in the numerical model creates an elevation difference against the actual terrain, which in turn makes the quality control of 2-m temperature difficult when forecast or analysis fields are utilized in the process. In this paper, a two-stage quality control method is proposed to address the quality control of 2-m temperature, using biweight means and a progressive EOF analysis. The study is made to improve the quality control of the observed 2-m temperature collected by China and its neighboring areas, based on the 6-h T639 analysis from December 2009 to February 2010. Results show that the proposed two-stage quality control method can secure the needed quality control better, compared with a regular EOF quality control process. The new method is, in particular, able to remove the data that are dotted with consecutive errors but showing small fluctuations. Meanwhile, compared with the lapse rate of temperature method, the biweight mean method is able to remove the systematic bias generated by the model. It turns out that such methods make the distributions of observation increments (the difference between observation and background) more Gaussian-like, which ensures the data quality after the quality control.


2017 ◽  
Vol 37 (1) ◽  
pp. 41-44
Author(s):  
Karol Grochalski ◽  
Katarzyna Peta

Abstract Article presents the methods of detecting defects within material with the use of active infrared thermovision. During the study ABS and PVC samples were used inside which internal structure defects and defects of glue conjunction between components were modeled. During combining composite materials with the use of glue joints, there is a problem with homogenous distribution of the glue layer on the surface of an element, which results in the creation of defects in joint structure and the decline of active surface of adhesion forces on the combined materials. It is then necessary to control the quality of the conjunction between the glued surfaces. The use of non-contact diagnostic methods allows to analyze a larger surface which conditions in more efficient quality control process. In the study, external heat excitation was used - optical excitation with periodic variable signal (LockIn method) and unit step excitation (Pulse method). The methods of analysis of the obtained thermograms are presented.


PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247925
Author(s):  
Pooi-Mun Wong ◽  
Shreya R. K. Sinha ◽  
Chee-Kong Chui

Blockchain has been applied to quality control in manufacturing, but the problems of false defect detections and lack of data transparency remain. This paper proposes a framework, Blockchain Quality Controller (BCQC), to overcome these limitations while fortifying data security. BCQC utilizes blockchain and Internet-of-Things to form a peer-to-peer supervision network. This paper also proposes a consensus algorithm, Quality Defect Tolerance (QDT), to adopt blockchain for during-production quality control. Simulation results show that BCQC enhances data security and improves defect detections. Although the time taken for the quality control process increases with the number of nodes in blockchain, the application of QDT allows multiple inspections on a workpiece to be consolidated at a faster pace, effectively speeding up the entire quality control process. The BCQC and QDT can improve the quality of parts produced for mass personalization manufacturing.


AGROINTEK ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 72
Author(s):  
Andan Linggar Rucitra ◽  
S Fadiah

<p><em>Telon oil is</em><em> one of </em><em> </em><em>the </em><em>traditional medicine in the form of </em><em> </em><em>liquid preparations that serves to provide a sense of warmth to the wearer. PT</em><em>.X</em><em> is one of the companies that produce</em><em> </em><em>telon</em><em> oil</em><em>.</em><em> To maintain</em><em> the quality of telon oil from PT.X</em><em> product</em><em>, required overall quality control that is starting from the quality control of raw materials, quality control process to the quality control of the final product. The purpose of this research is to know the application of Statistical Quality Control (SQC) in controlling the quality of telon oil in PT X. </em><em>F</em><em>inal product</em><em> quality</em><em> become one of the measurement of success of a process, so it needs a good quality control. SQC method used in this research is Pareto Diagram and Cause and Effect Diagram. Pareto diagram is a bar graph </em><em>that </em><em>show the problem based on the order of the number of occurrences of the most number of problems until the least happened. A causal diagram is often called a fishbone diagram, a tool for identifying potential causes of an effect or problem. The result of applying the method indicates that 80% defect is caused by unsuitable volume and on the incompatibility of Expired Date (ED) code. The damage is caused by several factors namely the method, labor, and machine while the most potential factor is the volume conformity to reduce the number of defect products.</em></p>


Author(s):  
A. V. Samonov ◽  
S. A. Sharov

The work looks at directions of developing regulatory and procedural and technological basis of weapons system software control and quality assurance processes. We present an improved software life cycle model and describe an automated technique of implementing a systemic end-to-end software quality control process.


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