Quality Accident Research Articles

A STUDY ON INTERNATIONAL COMMUNICATION STANDARDS AND PERFORMANCE STANDARDS FOR SMART WATER QUALITY SENSORS

The world is now building an artificial intelligence (AI) water quality management system to detect water quality accidents at an early stage and predict water quality vulnerable areas in advance beyond measuring the water quality. In other words, by applying big data analysis and artificial intelligence technology to the conventional water quality measurement system that monitors water quality in real time, an artificial intelligence-based water quality measurement and water quality prediction system is built at the same time, and drones and unmanned ships are also introduced. It means implementing water quality management. Water quality accident prediction based on artificial intelligence measures water quality throughout the site of use through intelligent spatial analysis based on the integrated water quality database. On the other hand, the location of the site detected through artificial intelligence is displayed on the comprehensive monitoring screen, and special management such as on-site monitoring, replacement of consumables, and maintenance is carried out to prevent water quality accidents. In particular, the prediction accuracy of artificial intelligence is to create an algorithm for predicting future values by learning the characteristics and patterns of accumulated data. It depends on the function of the smart sensor itself. However, until now, there has been no international standard for smart sensors, so it was difficult to establish system interlocking or modularization for each manufacturer and site. Therefore, we present the most important standard communication standards for smart water quality sensors in the field and international standard performance specifications for smart sensors, and this research data is provided to all organizations engaged in water quality around the world for water quality measurement and prediction system data system for AI application.

Design of Tool Information Error Prevention Based on FIDIA

It often takes place in the field of CNC machining that quality accident of parts due to the tool information entry incorrect. In this paper, an error check program based on FIDIA CNC system is designed. The tool information in FIDIA CNC system is read by AUCOL program and compared with the theoretical tool length value to judge whether the tool information is correct, so as to reduce the tool information error in CNC system caused by human error.

A Study on the Delineation of Flushing Sections and Simulation Method to Verify Appropriate Flushing Velocity for Applying Flushing

Recently, water supply networks have experienced deterioration because of various factors, which result in the accumulation of a large amount of scale on the inside surface of pipes. The scale may enter houses when a surge occurs owing to abrupt velocity or flow direction change in pipes, and eventually, water quality accident such as red-water can occur. The scale should be removed by applying pipe-cleaning practices, such as flushing, to prevent this type of accident. Currently, most studies have suggested only the desirable flow velocity to remove the scale through flushing. In our opinion, it will be more critical to develop a method for determining whether it would be possible to achieve the desired flow velocity. Hence, we developed a method to delineate a flushing section and modify a water supply network in considering the minor loss on the hydrant using the head loss-flow rate curve for the hydrant. Next, we simulated a flow condition using the emitter coefficient to achieve the desired flow velocity for flushing each section. The proposed method was applied to a part of the water supply network of a city in Korea. From the results, the pressure head at the primary water source point of the network was sufficient such that each flushing section experienced the desired flow velocity to complete the flushing process. We lowered the pressure head by 20 m at the primary water source point and simulated a flow condition for insufficient pressure head. Under these conditions, some of the flushing sections could not experience the desired flow velocity, and hence, the scale could not be removed as desired. In this case, we believe that the utility authority should decide whether flushing is still a suitable option for cleaning the pipe, or whether other cleaning methods should be considered.

Root cause analysis approach based on reverse cascading decomposition in QFD and fuzzy weight ARM for quality accidents

Quality accidents (QAs) of high frequencies in various fields have caused large economic and reputational losses to manufacturers, and identification of the root causes of vicious QAs is a top priority and a major challenge for manufacturers. Especially in the era of big data, the large number of data could be collected from the product life cycle easily, these high-dimensional big data always bear so many un-correlation noise information, which has caused serious problem. The accurate and heuristic root cause analysis for QAs is an important and challenging task in exploring this mechanism due to the fuzzy and vague nature of the collected big quality data. Thus, in this study, a heuristic root cause identification solution based on the fuzzy weighted association rule mining (FWARM) for QAs is proposed. First, the formation mechanism of QAs and big quality accident data is expounded, and a big data driven root cause analysis framework of QAs is presented with the aid of reverse cascading decomposition in Quality Function Deployment (QFD). Second, principal component analysis (PCA) is adopted to eliminate redundancy and reduce data dimension of original process feature parameters from raw data in low-dimensional space so that the key variables as the potential root cause candidates can be extracted. Third, considering the fuzzy mechanism and vague nature of big data, a heuristic root cause identification approach based on FWARM is established, and the weight of nodes on the accident-relevance tree is computed by fuzzy weight coefficient. Finally, the proposed approach is verified with a case study of a quality accident analysis of a washing machine. Results shows that the proposed approach is conducive to heuristically identify the root causes of QAs in the context of big data.

QUALITY CREDIT EVALUATION IN THE INTERNET COMPANY: A SYSTEM BASED ON THE ANALYTIC HIERARCHY PROCESS

Quality credit has attracted considerable interest in both academia and business world in recent years in China. This study aims to discuss the development of quality credit evaluation system, and then based on an Analytic Hierarchy Process (AHP) to construct an evaluation system for Internet companies. Firstly, the quality credit evaluation three-level pyramid model for Internet companies has been established, including the willingness of quality credit, the ability of quality credit, and the basis of quality credit. Secondly, priorities of the criteria and sub-criteria are assigned and identified by the AHP with 12 experts those who are representatives from Internet companies, research experts, and government staffs. Finally, several US Internet companies are evaluated by using this evaluation system, and practical suggestions are provided for the future based on data evaluation results. This paper finds that in the criteria of quality credit evaluation system, the most significant indicators are credit records and quality of product, while qualification rate of product supervise, operating legitimacy and quality accident are the most primary indicators in the sub-criteria level.

Formation of N-nitrosodimethylamine by chloramination of anthropogenic nitrogenous compounds with dimethylamine monitored by Japanese water authorities.

Pollutant release and transfer registers (PRTRs) compounds accidentally released to source waters can be important precursors of the carcinogenic N-nitrosodimethylamine (NDMA) during drinking water treatment. The NDMA formation potentials (NDMAFPs) of 31 anthropogenic nitrogenous compounds with dimethylamine (DMA) moiety on the Japanese PRTR and the registered precursors listed by the Ministry of Health, Labour and Welfare of Japan are investigated as well as influencing factors (i.e., NH2Cl dose and water matrices) on the NDMAFPs of precursors. Tertiary amines with aryl groups β-positioned to the nitrogen atom of the DMA moiety formed high concentrations of NDMA (35-51%) during chloramination. Moreover, dimethylcarbamoyl chloride (DMCCl) was considered a new NDMA precursor with NDMAFP of 1.1%, higher than DMA, a traditional NDMA precursor. Excessive NH2Cl dose enhanced the NDMA formation, and the NDMAFP of DMCCl significantly decreased in river water; the effect of the matrix in river water varied and was compound-specific. Among the selected nitrogenous compounds, NDMAFPs of 15 excessed the current guideline concentration for NDMA in Japan (100 ng/L) assuming an accidental release of 0.144 mg C/L (the concentration in previous Japanese water quality accident in May 2012), and 2-(dimethylaminomethyl) thiophene (DMAMT) showed the highest NDMAFP at 58 μg/L.

Risk-based quality accident ranking approach using failure mechanism and Axiomatic domain mapping

Manufacturers face numerous product quality accidents and thus require an effective and general approach to rank the occurred quality accidents. Therefore, a universal risk-based quality accident ranking method emphasising the importance of the accident formation mechanism is proposed in this paper to rank, analyse, and prevent occurred quality accidents comprehensively. First, the risk formation mechanism of quality accident is proposed emphatically using two typical failure mechanisms and Axiomatic domain mapping, and the structure of big quality accident data is presented on the basis of big product lifecycle data in order to provide data support for the subsequent risk analysis. Second, the accident failure cost, probability, and detectivity are adopted as the critical risk factors, which are computed using the failure cost model, extended fault tree and Axiomatic relevance tree respectively. Third, a modified risk importance index considering the relative weight of risk factors is presented to measure and rank the risk priority of quality accidents. Finally, a case study on a computer control panel accident risk analysis is conducted to verify the effectiveness of the proposed approach. Results show that the proposed method can objectively reflect the accident risk degree and provide necessary reference for accident risk mitigation.

Product Quality Accidents Risk Analyzing Approach based on the Extended FTA and Failure Cost

Various type quality accidents occurred and reported in the field of different product in the large manufacturing companies, how to identify the root causes and rank the mitigation measures are always a puzzle for their quality and after-sales departments. Therefore, in order to improve the failure mechanism modeling ability of quality improvement methods, the extended FTA (Fault tree analysis) considering the common cause failures effect and failure cost are introduced into the risk analysis for product quality accident at the first time. Firstly, risk analysis basics for quality accident of risk formation mechanism, common cause failures and extended FTA model are defined. Secondly, quality accident risk computation model based on failure cost is presented to quantitate the risk. Thirdly, an integrated quality accident risk analysis approach is established, which includes the root causes analyzing and safety measures ranking. Finally, a case study of quality risk analysis for cooling system is carried out to verify the proposed method.

System Analysis of Construction Quality Control Measures of Coastal Levee

The phenomenon of the actual situation leave the design index is very common during the civil project construction especially in the coastal levee construction. As the way to reduce the probability of diseases occurrence, from the aspect of quality accident analysis, construction quality monitoring moisture, quality inspection and accident early warning system, the paper studied the levee construction quality control monitoring system deeply and advanced some useful conclusion.

Formaldehyde formation from tertiary amine derivatives during chlorination

In May 2012, formaldehyde (FA) precursor contamination in the Tone River Basin led to the suspension of water supply to approximately 360,000 homes, which affected approximately 870,000 people in the Tokyo Metropolitan Area. The discharge of industrial effluents containing hexamethylenetetramine (HMT), a tertiary amine and FA precursor, without proper treatment resulted in the formation of FA during chlorination at water purification plants. Tertiary amines are known to be the precursors of aldehydes upon chlorination. In this study, FA formation from 29 separate amine derivatives during chlorination was investigated to determine any other potential causes of this water quality accident. The FA formation yield also included FA formation by the autolysis of the target compounds as well as the chlorination of the autolysis products. The FA molar formation yield of HMT was the highest after 24h of chlorination (440%). Among the various tertiary amine derivatives containing N-methyl groups, tertiary amines and hydrazines were found to be strong FA precursors because the FA molar formation yields per N-methyl group ranged from 25% to 45% (with a mean of 38%) and from 35% to 45% (with a mean of 41%), respectively. Guanidines and sulfamides containing N-methyl groups were also FA precursors but they exhibited lower FA molar formation yields per N-methyl group. The FA molar formation yields of the remaining compounds were <4%. The FA formation yield of HMT was extremely high even on a per weight basis (95wt.%). The FA weight formation yields of some tertiary amines and hydrazines were greater than 20wt.%.

A Discussion on Causes and Preventive Measures for Construction Quality Accident

A long lasting project, quality is priority. The quality directly determines the success of project. The excellence of a building quality is not only the pulchritude of a countrys construction, but also the guarantee of safety of life and wealth. However, due to non-standardizing of construction market and disarray of internal management, the quality accident often occurred. This paper, based on engineering practice in projects, analyzes causes for common construction quality accident from design, materials construction supervision and some other factors, puts forward some typical engineering examples, and offers corresponding preventive measures to reduce the occurrence of construction quality accident.

パルプ設備FRP劣化による品質トラブルと対策

パルプ設備FRP劣化による品質トラブルと対策

On Blueprint-Auditing by Management Engineers

The construction drawing is a design document by which each construction party should abide. It is also a key element to affect construction project quality. So in the stage of supervision, the important thing that management engineers must grasp is blueprint-auditing. They should grasp the auditing principle, auditing method, auditing content and results，through which the problems existed among design, construction, process, engineering materials, equipments, etc. as well as those in each profession can be timely discovered. Through which, most design problems can be resolved before construction and the quality accident can be removed at its initial point. As a result, the construction time and cost can be saved a lot.

Experimental Study about Testing Masonry Shear Strength with Drilled Core Method

Key technology of testing masonry shear strength with core drilling method is that standard shear strength of masonry is determined from the shear strength of masonry core sample, while current code or specification has not provided the corresponding calculating formula. To investigate their relationship, a series of tests have been carried out. Existing test result analysis shows that standard shear strength of masonry and shear strength of masonry core sample are closely related. By means of testing data regression analysis, this work can establish the relationship formula between shear strength of single core sample and standard shear strength of masonry. This Technology can be suitable both to traditional masonry structure and to new wall materials masonry structure, especially to seismic appraiser and reinforcement calculation of masonry structure. This technology can support scientific basis to quality examination and assessment of new wall materials and analysis of engineering quality accident.

Numerical Analysis on the Characteristics of Settlement Deformation of the High Rock-Filled Embankment during the Construction Period

Embankment filling is a process step by step. The influences of its filling height changes on the stress and deformation can not be reflected in a load. However, in the actual construction, it leads to quality accident in embankment construction that filling usually doesn’t control the thickness according to the requirement of construction specification. In order to reveal the stress and strain law of about 72 m high rock-filled embankment during the construction, and provide a scientific reference to construction quality control of the embankment, according to the typical cross section of the Hurongxi highway, using two loading modes to simulate the embankment filling, the internal stress, strain and corresponding graphics of different control points of the embankment under the various loads were presented. The results of the two loading modes are analyzed and compared. It shows that the settlement, stress and construction quality control points of the embankment are different and larger under the different loading

Emergency Measure on Water Quality Accident in Lake Biwa and River Yodo System

Water quality accidents caused by sudden intrusion of oils or chemical materials into rivers sometimes stop intake of water supply and give damage on social life. In the lake Biwa and river Yodo system, 31 times accidents occurred in 1994/95 fiscal year, most of them reported widely on the mass-media. At present, the safety or security is highlighted in the public, risk control is serious theme.On the occasion of accidents, river administrators, water suppliers, and organizations concerned, make every efforts and collaborate to inform rapidly and take countermeasures accurately, however, it is usually difficult to identify the material and solve the origin.

Managing the Risks of the Automobile: A Study of a Swedish Car Manufacturer

Hazard management of the risks of human injury and death related to the automobile are described and exemplified by the Swedish car manufacturer Volvo. The study presents the Volvo units engaged in accident hazard management and their roles in the elaborate system of feedbacks (information, penalties and rewards) created by the company and society for maintaining a high level of automobile safety. Improvements are suggested although the overall quality of the accident hazard management process is considered quite good. Although the study is focused on the automobile industry, it should be regarded as part of a much-needed wider perspective on hazard management applying to other technologies and industries as well. In general, the following factors are considered important to high quality accident hazard management by companies and society: (1) Public concern about safety issues, (2) technological capacity and organizational tradition of safety engineering in the manufacturing company, (3) routines for announcing future proposed safety standards, e.g., US Federal Register, (4) laws enforcing a recall system, (5) annual vehicle inspections and (6) effective product liability laws.