Cause Of Malfunction Research Articles

Biomimetic ultra-bubble-repellent surfaces based on a self-organized honeycomb film.

The adhesion of bubbles underwater remains the greatest cause of malfunctions in applications such as microfluidics, medical devices and heat exchangers. There is therefore an emerging need for ultra-bubble-repellent surfaces. Inspired by fish scales, which show high bubble repellency due to their hydrophilic nature and surface microstructures, we propose a novel method for preparing ultra-bubble-repellent surfaces by the hydrophilic treatment of self-organized microstructures. When in contact with air bubbles underwater, the artificial hydrophilic microstructured surfaces had a higher contact angle and a lower adhesion force than a flat surface. The mechanism leading to these properties is also investigated. Our method for the fabrication of ultra-bubble-repellent, hydrophilic, microstructured surfaces is simple and cost-effective, opening the way for its application in artificial devices, such as the inner surfaces of tubes, medical devices, and heat exchangers.

The role of laparoscopic surgery in the management of a malfunctioning peritoneal catheter.

Peritoneal catheter malfunction is a common complication of peritoneal dialysis (PD). It has a high failure rate with conservative management. Catheter replacement was historically the standard surgical treatment of choice. Nowadays, laparoscopy has been introduced as an alternative surgical modality to rescue the malfunctioning peritoneal catheter and also offers the possibility of replacement if indicated. The aim of this study was to compare the outcomes of these two surgical modalities. The medical records of consecutive patients who underwent surgical treatment for malfunctioning PD catheters (between January 2010 and April 2013) were analysed. The primary outcome included successful return to adequate PD. The secondary endpoint was length of catheter patency and the cause of catheter failure. A total of 32 cases were identified, of which 8 had open catheter replacement and 24 had a laparoscopic intervention. The overall median follow-up duration was 12.5 months. The success rate for laparoscopic surgery in terms of functioning catheter at 12 months was 62.5% but only 37.5% for open surgery. The mean length of catheter patency after laparoscopic intervention was 31.6 months compared with only 13.6 months for the open surgery group. The most common cause of catheter failure diagnosed during laparoscopic intervention was catheter migration (33.0%), followed by omental wrap and catheter blockage by fibrin/blood plug (25.0% each). Open surgery did not have any diagnostic potential. Laparoscopy is the treatment of choice for malfunctioning PD. Its proven benefit includes simultaneous identification of the aetiological cause of malfunction together with direct correction of this problem, thereby maximising outcome. It also allows for rapid recommencement of PD and avoidance of haemodialysis, saving cost and resources.

Automatic Lubrication System for Minimizing Friction of Driving Parts for Large-Sized Commercial Vehicle

One of the causes of malfunction of commercial vehicle is corrosion or wear. In order to prevent corrosion and wear, lubricants have to be supplied periodically. However, the period of lubrication usually depends on operator's judgment. If the period is too short, excess lubricant will cause pollution and unnecessary expenses, whereas long periodic supply of lubricant might cause wear, damage and eventual breakdown. Therefore, an automatic lubrication system with predetermined interval will reduce the excessive supply of lubricating oil and prevent wear and damage. This thesis presents an automatic lubrication system which consists of a lubricant pump and an embedded controller. An automatic lubrication operating algorithm is used to operate the lubricant pump and feedback the pressure status of the system using pressure sensors. The developed system shows an efficient periodic supply of lubricant.

Reliability of Telecommunications Systems Following a Major Disaster: Survey of Secondary and Tertiary Emergency Institutions in Miyagi Prefecture During the Acute Phase of the 2011 Great East Japan Earthquake

Telecommunication systems are important for sharing information among health institutions to successfully provide medical response following disasters. The aim of this study was to clarify the problems associated with telecommunication systems in the acute phase of the Great East Japan Earthquake (March 11, 2011). All 72 of the secondary and tertiary emergency hospitals in Miyagi Prefecture were surveyed to evaluate the telecommunication systems in use during the 2011 Great Japan Earthquake, including satellite mobile phones, multi-channel access (MCA) wireless systems, mobile phones, Personal Handy-phone Systems (PHS), fixed-line phones, and the Internet. Hospitals were asked whether the telecommunication systems functioned correctly during the first four days after the earthquake, and, if not, to identify the cause of the malfunction. Each telecommunication system was considered to function correctly if the hospital staff could communicate at least once in every three calls. Valid responses were received from 53 hospitals (73.6%). Satellite mobile phones functioned correctly at the highest proportion of the equipped hospitals, 71.4%, even on Day 0. The MCA wireless system functioned correctly at the second highest proportion of the equipped hospitals. The systems functioned correctly at 72.0% on Day 0 and at 64.0% during Day 1 through Day 3. The main cause of malfunction of the MCA wireless systems was damage to the base station or communication lines (66.7%). Ordinary (personal or general communication systems) mobile phones did not function correctly at any hospital until Day 2, and PHS, fixed-line phones, and the Internet did not function correctly at any area hospitals that were severely damaged by the tsunami. Even in mildly damaged areas, these systems functioned correctly at <40% of the hospitals during the first three days. The main causes of malfunction were a lack of electricity (mobile phones, 25.6%; the Internet, 54.8%) and damage to the base stations or communication lines (the Internet, 38.1%; mobile phones, 56.4%). Results suggest that satellite mobile phones and MCA wireless systems are relatively reliable and ordinary systems are less reliable in the acute period of a major disaster. It is important to distribute reliable disaster communication equipment to hospitals and plan for situations in which hospital telecommunications systems do not function.

Evaluation of the Defects of Removable Partial Dentures’ (RPD) Frameworks Made in Prosthodontics Department Of Qazvin Dentistry School Regarding Retention, Stability, and Support

Background: The metal framework of a removable partial denture includes various parts and metal components that supply strength, retention, stability, and support of partial denture. The purpose of this study is assessing the quality of the frameworks made in the department of prosthodontics, Qazvin school of dentistry, regarding their causes of malfunction, retention, stability, and support.&#x0D; Materials and Methods: Evaluation forms of removable partial denture metal frameworks for upper and lower jaws were separately designed. According to the forms, 39 frameworks were fitted and assessed on encoded casts and after that in oral cavity.&#x0D; Results: 11 males and 28 females (44±4.8 years old) were recruited in the study; 17 frameworks belonged to maxilla and 22 to mandible. In maxillary frameworks, 10 cases (58.8%) had goodretention, 6 (35.3%) had low and 1 (5.9%) had high retention. Moreover, 15 cases (88.2%) and 11 cases (71.64%) showed good support and stability, respectively, in all 3 hypothetical axes. Inmandibular frameworks, retentions in 14 cases (63.3%) were good, in 7 (8.31%) were low and in1 (4.6%) was high. Furthermore, 16 cases (72.7%) and 12 cases (54.5%) showed good supportand stability, respectively, in all hypothetical axes.&#x0D; Conclusion: The retention, stability and support of metal frameworks were approximatelyacceptable and appropriate. Most of the malfunctions and structural problems seem to be due to lack of experience and expertise. However, further studies and more training courses are needed to enhance the quality of these frameworks.

重要業務継続を目的とした建物管理システムの開発

Resilience of buildings will be improved by revising the methods of building management. This paper discusses the development of a new building management system for continuance of important operations. In the early stages after a disaster, it is important to judge what has happened, what are the actual conditions, whether important operation spaces can be used, what are the causes of malfunctions, what to do to achieve continuity of function and early restoration of function. This report presents a methodology to support the process of confirming the actual conditions, judgment, adjustment, and action systematically, for the building manager.

Advanced Diagnosis of Control Loops: Experimentation on Pilot Plant and Validation on Industrial Scale

The paper presents main features of a performance monitoring system, which, in addition to variables normally registered in industrial plants (controller output OP, controlled variable PV and set-point SP), makes use of additional variables made available by intelligent instrumentations and field bus communication systems. Experimental runs on a pilot plant scale have been carried out in order to introduce different types of valve malfunctions and to define suitable indices (KPI) able to diagnose them. Subsequently, threshold values for the indices have been calibrated and a logic has been developed to assign different performance grades. It is shown how the Travel Deviation allows specific evaluation of valve status and to detect different causes of malfunctioning. The same logic is implemented in an advanced release of an existing performance monitoring system and advantages in the accuracy of diagnosis are shown. Finally the system has been successfully validated by online implementation for control loops assessment of an industrial power plant.

Rolling bearing fault detection using an adaptive lifting multiwavelet packet with a dimension spectrum

Defect faults on the surface of rolling bearing elements are the most frequent cause of malfunctions and breakages of electrical machines. Due to increasing demands for quality and reliability, extracting fault features in vibration signals is an important topic for fault detection in rolling bearings. In this paper, a novel adaptive lifting multiwavelet packet with dimension spectrum to detect defects in rolling bearing elements is developed. The adaptive lifting multiwavelet packet is constructed to match vibration signal properties based on the minimum singular value decomposition (SVD) entropy using a genetic algorithm. A dimension spectrum is further employed to extract rolling bearing fault characteristic frequencies from background noise. The proposed method is applied to analyze the vibration signal collected from electric locomotive rolling bearings with outer raceway and inner raceway defects. The experimental investigation shows that the method is accurate and robust in rolling bearing fault detection.

대형상용차량을 위한 소형전기식 윤활유 자동 공급시스템 구현

One of the causes of malfunction of commercial vehicle is corrosion or wear. In order to prevent corrosion and wear, lubricants have to be supplied periodically. However, the period of lubrication usually depends on operator`s judgment. If the period is too short, excess lubricant will cause pollution and unnecessary expenses, where as long periodic supply of lubricant might cause wear, damage and eventual breakdown. Therefore, an automatic lubrication system with predetermined interval will reduce the excessive supply of lubricating oil and prevent wear and damage. This thesis presents an automatic lubrication system which consists of a lubricant pump and an embedded controller. An automatic lubrication operating algorithm is used to operate the lubricant pump and feedback the pressure status of the system using pressure sensors. The developed system shows an efficient periodic supply of lubricant.

Malfunction Theory as a Triple Threat for the Defense

MALFUNCTION THEORY allows plaintiffs in a products liability case to prove the probability of a defect by eliminating normal causes of malfunctions, even without proving the specific existence of a product Plaintiffs have applied malfunction theory to devastating effect on the defense of a products liability case, which is already a plaintiff-friendly environment. Courts throughout the nation are utilizing and developing malfunction theory to relax, or even excuse proof of defect and causation in products liability cases. This article argues that malfunction theory poses a triple threat to defendants by: (i) removing the requirement that plaintiffs prove a specific product defect; (ii) relaxing the causation requirements that plaintiffs must show; and (iii) potentially allowing plaintiffs' experts to provide otherwise impermissibly unsupported opinions. However, at least one recent case provides the possibility that unsupported expert testimony presents the Achilles heel to this otherwise unbounded theory. I. Plaintiff-friendly Product Liability Law Product liability law essentially undid previous common law. Most notably, product liability law created a dangerous environment for any person operating in the stream of commerce by allowing claims against any defendant in the stream of commerce relative to the product with no privity requirement and without proof of fault. Courts also did away with the traditional requirement of proving fault, or negligence--allowing strict liability against any product seller. When neither privity of contract nor negligence is required, the burden often effectively shifts to defendants to figure out who is responsible for the harm allegedly caused to a plaintiff. Ordinarily in product liability cases in most jurisdictions, a plaintiff must prove that: a product was in a defective condition unreasonably dangerous to the consumer, the defect caused the injury, the defect existed at the time of sale, and the product was expected to and did reach the consumer without substantial change in condition. (2) The application of the malfunction theory to this already plaintiff-oriented body of law has the potential to expose defendants in the stream of commerce even further. Malfunction theory is being expanded in most jurisdictions, some in a very relaxed manner, to provide alternate ways in which plaintiffs may successfully bring a products liability case despite the lack of direct evidence of defect and/or causation due to factors such as destruction or loss of the product in question. Under varying circumstances in different jurisdictions, courts are permitting circumstantial evidence as the basis for a prima facie products liability case in the absence of direct evidence of defect, causation, or both. II. Malfunction Theory Basics A plaintiff in a product liability action may be able to establish a prima facie case by providing evidence of the nature of a product's malfunction under circumstances that give rise to an inference that the malfunction would not have occurred absent a defect existing at the time of sale. Product liability cases may arise out of a product malfunction that damages or completely destroys a product that is the basis of the products liability case. (3) As a result, plaintiff would not be able to produce direct evidence of a specific defect. The malfunction theory essentially allows a plaintiff to present circumstantial evidence of a defect or evidence of an unspecified dangerous condition when direct evidence is unavailable or there is insufficient evidence to identify the specific defect. Additionally, application of the malfunction theory allows the plaintiff to present circumstantial evidence that rules out reasonable secondary causes in lieu of direct evidence of causation. Given that the malfunction theory implicates permissible inferences for a fact-finder absent direct evidence, the theory essentially operates as a rule of evidence. …

전기시스템의 절전모드에 적용되는 PCB의 오작동 원인 개선에 관한 연구

The purpose of this study is to find the causes of malfunctions and defective operation of printed circuit boards(PCBs) built into home refrigerators to perform power saving functions. This study performed an electrostatic test of a PCB built-in using an Auto Triggering system; lightning and impulse tests using an LSS-15AX; and an impulse test using an INS-400AX. From the analysis of a secondarily developed product, it was found that electrostatic discharge(ESD) caused more malfunctions and defective operations than electric overstress(EOS) due to overvoltage. As a result of increasing the condenser capacity of the PCB circuit, withstanding voltage was increased to 7.4 kV. In addition, this study changed the power saving mode and connected a varistor to the #2 pin of an IC chip. As a result, the system consisting of all specimens of a finally developed product was operated stably with an applied voltage of less than 10 kV. This study found it necessary to perform quality control at the manufacturing stage in order to reduce the occurrence of electrostatic accidents to IC chips built into a PCB.

Analysis of Attribute Reduction of Rough Set and CNC Machine Fault Diagnosis Based on Particle Swarm

After reasoning and calculation, fault diagnosis can automatically identify the causes of malfunction based on the fault symptoms, which is the core task of fault diagnosis. This paper applies the particle swarm algorithm and rough set to the fault diagnosis, and proposes fault diagnosis knowledge acquisition, rules optimization and fault identification based on rough set attribute reduction of particle swarm. Firstly, this paper introduces the rough set attribute reduction. Secondly, the particle swarm algorithm is applied to the rough set attribute reduction algorithm. Finally, the correctness and superiority of this algorithm are proved from the reduction experimental results of related data sets.

Pyroelectric sensor signals processing for early-warning generation in CO 2 laser welding

Three different techniques were chosen for processing pyroelectric sensor signals that would provide early warnings of malfunctioning in the CO 2 laser welding. The corresponding algorithms were implemented using the mean, the root mean square and variance of a suitable number of digitized signal samples. Each pair of these algorithms was found complementary in reaching 100% success in the early individuation of the defects. The one based on the variance was more efficient than the other two in identifying the causes of malfunctioning. The processing times ranged from 20 μs to 200 ms, and the spatial resolutions varied from 18 μm to 0.5 mm.

Fault Diagnosis with Fuzzy Expert System

Locating the causes of malfunctions in complex energy systems is an extremely difficult task, more than one fault mode may produce similar and possibly undistinguishable patterns of effects. This paper shows how fuzzy expert systems can exploit the available measurements from the data acquisition system to identify different component and sensor fault modes. Real sensor data (mass flow rates, pressures, temperatures, and key operating parameters) are compared with the expected values of the same quantities that are calculated using numerical models of local subsystems. The final objective is to verify the existence of some patterns of these attributes that univocally identify the considered fault modes. These patterns are then implemented as the set of rules forming the knowledge based on fuzzy expert system.

Simulation of Failure Detection Based on Neural Network for No-Ball Mill

According to the structural characteristics of non-ball mill, using the neural network theory to select and measure point, set the failure mode, analyze and determine the cause of malfunction. The newly developed fault detection system was used to simulative detect fault. Through data processing, the results can be directly derived which could be fed back into the design of non-ball mill, thereby improving the design.

Analysis and Solutions of Three Combined Test Chamber's Malfunction Based on the Working Process

In order to found out the reason that return-air overheated in the main preceding refrigeration compressor of three combined test chamber, and for trouble shooting effectively, carried out the analysis and searching fault based on course of work. At first, analyzed and judged the possible reasons that caused overheat base on experiment and common practice, but couldn’t determine it, then, inspected the compressor and adjusted valves, but couldn’t solve problem yet, finally through efforts and depth profile analysis, the real causes of malfunction were founded: there were some micronic leakage points in one of the manual valves and unloading valve of compressor in the high-pressure part of the system. The freezing medium in the system gradually missed from it on the high pressure line during long time operation, so when the leakage points were handled, the problem is properly settled. In this paper, methods and process of malfunction elimination as well as malfunction features and manifestation of the equipment in every maintenance procedure and the key to the final solutions are elaborated, which hopefully provides reference value and meaning for the maintenance of equipment of the same kind.

Real-time fault detection and isolation in biological wastewater treatment plants

Automatic fault detection is becoming increasingly important in wastewater treatment plant operation, given the stringent treatment standards and the need to protect the investment costs from the potential damage of an unchecked fault propagating through the plant. This paper describes the development of a real-time Fault Detection and Isolation (FDI) system based on an adaptive Principal Component Analysis (PCA) algorithm, used to compare the current plant operation with a correct performance model based on a reference data set and the output of three ion-specific sensors (Hach-Lange gmbh, Düsseldorf, Germany): two Nitratax NOx UV sensors, in the denitrification tank and downstream of the oxidation tanks, where an Amtax ammonium-N sensor was also installed. The algorithm was initially developed in the Matlab environment and then ported into the LabView 8.20 (National Instruments, Austin, TX, USA) platform for real-time operation using a compact Field Point, a Programmable Automation Controller by National Instruments. The FDI was tested with a large set of operational data with 1 min sampling time from August 2007 through May 2008 from a full-scale plant. After describing the real-time version of the PCA algorithm, this was tested with nine months of operational data which were sequentially processes by the algorithm in order to simulate an on-line operation. The FDI performance was assessed by organizing the sequential data in two differing moving windows: a short-horizon window to test the response to single malfunctions and a longer time-horizon to simulate multiple unrepaired failures. In both cases the algorithm performance was very satisfactory, with a 100% failure detection in the short window case, which decreased to 84% in the long window setting. The short-window performance was very effective in isolating sensor failures and short duration disturbances such as spikes, whereas the long term horizon provided accurate detection of long-term drifts and proved robust enough to allow for some delay in failure recovery. The system robustness is based on the use of multiple statistics which proved instrumental in discriminating among the various causes of malfunctioning.

A Global and a Local Approach With Evolutionary Algorithms to Locate Malfunction Causes in Energy Systems

Energy system performance may differ from the expected one during actual operation because of the effects of faults, anomalies, and wear and tear due to normal use. One of the main issues of diagnosis, i.e., the procedure to discover the causes of malfunctions, is to find the way back from measured altered performance to the original cause. Several procedures were proposed in the literature to solve the diagnostic problem, usually based on the comparison between a reference nonmalfunctioning condition and an actual, possibly malfunctioning, condition. A different strategy is suggested in the paper. A direct search of the possible causes of malfunctions is performed by means of an evolutionary algorithm: a component fault is arbitrarily introduced in a model of the healthy system by substituting the reference characteristic curve with an altered one, and the algorithm is used to search for a combination of different kinds of performance modifiers that generates the same measured effects of the actual anomaly. A global and a local approach are proposed and applied to a real test case plant, also in presence of measurement noise. The local approach demonstrates to be more effective in terms of accuracy and computational effort.

Fuzzy Expert Systems for the Diagnosis of Component and Sensor Faults in Complex Energy Systems

Abstract Locating the causes of malfunctions in complex energy systems is an extremely difficult task, since more than one fault mode may produce similar and possibly undistinguishable patterns of effects. This paper shows how fuzzy expert systems can exploit the available measurements from the data acquisition system to identify different component and sensor fault modes. Real sensor data (mass flow rates, pressures, temperatures, and key operating parameters) are compared with the expected values of the same quantities that are calculated using numerical models of local subsystems. This comparison simply determines if the differences between measured and expected values are “negative,” “zero,” or “positive” in fuzzy logic terms. The final objective is to verify the existence of some patterns of these attributes that univocally identify the considered fault modes. These patterns are then implemented as the set of rules forming the knowledge base of a fuzzy expert system. The proposed diagnostic methodology is tested on the gas section of a real combined-cycle cogeneration plant, and the effect of measurement noise is also discussed.

Stress in Evaporated and Sputtered Thin Films – A Comparison

Stress in thin films and heterostructures is often the cause for malfunction of respective applications, but enables also the controlled engineering of novel materials properties. In the last years considerable progress has been achieved in understanding the mechanisms for stress evolution and relaxation. Whereas originally the stress generation appeared to be strongly dependent on the chosen deposition technique, it turned out that many of the involved stress mechanisms apply independently of the deposition technique and are intrinsically determined by the growth process. A comparative review of recent results on the stress of polycrystalline and epitaxial thin films prepared by evaporation and sputtering techniques will be given. The review focuses on stress results measured in situ during the film deposition.