Cause Of Malfunction Research Articles

Air-Stable Aerophobic Polydimethylsiloxane Tube with Efficient Self-Removal of Air Bubbles.

The adherence of underwater air bubbles to surfaces is a serious cause of malfunction in applications such as microfluidics, transport, and space devices. However, realizing spontaneous and additional unpowered transport of underwater air bubbles inside tubes remains challenging. Although superhydrophilic polydimethylsiloxane (PDMS) tubes are attracting attention as air bubble repellents, superhydrophilic PDMS, which is fabricated via oxygen plasma treatment, has a disadvantage in that it is weak against aging. Here, we present a tube with the ability to self-remove air bubbles, which overcomes the drawback of rapid aging. PDMS containing Silwet L-77 with a hierarchical nano–microstructure exhibiting subaqueous aerophobicity was fabricated. We conducted adherence and saturation experiments of air bubbles using the fabricated PDMS tube with Silwet L-77 to investigate the mechanism of bubbles adhering to and separating from the fabricated tube surface. The developed PDMS with Silwet L-77 exhibits a strong self-removal effect with an air bubble removal of 97.7%. The adherence and saturation experiments suggest that the transparent superhydrophilic–underwater aerophobic PDMS is a potentially exceptional tool for spontaneously separating air bubbles attached to tube surfaces.

A grid model to address the behaviour of the nodes in the dissemination of information

PurposeThis paper aims to present a framework to address the impact of people’s behaviour in the dissemination of information through mobile social networks.Design/methodology/approachThis approach follows the epidemical compartmental models and uses a grid to model the nodes’ (people) behaviour in the dissemination process. The nodes’ status is determined by binary rules that update and define the flow of information between neighbour nodes. An improved stacked-layer grid model is used to implement modulations in the application of the rules and neighbourhoods to model the impact of people’s attitude, which may improve or jeopardize the efficiency of the process.FindingsThis proposal shows how grid architecture is a valuable tool to model different causes of malfunction of data dissemination. Combining different grids with different neighbourhoods and different local rules provides a wide range of possibilities to depict the impact of human awareness and decision on the dissemination of data.Originality/valueThis works develops a new approach for the analysis of dissemination of information which add new features to traditional methods for modelling local interactions and describing the dynamics of the communication patterns in the population.

Numerical study for diagnosing various malfunctioning modes in PEM fuel cell systems

The proton exchange membrane fuel cell (PEMFC) is promising technology for efficient power generation and has wide applications. In PEMFC development, it is important to diagnose malfunctions in a system with defective components and a PEMFC stack can act as an effective sensor to detect the various malfunctioning modes. Hence, the focus of this study is to analyze the response of a PEMFC under various malfunction conditions including humidifier, air blower, and coolant pump, catalyst layer degradation, and membrane aging based on 3D PEMFC simulations. Except for the coolant supply malfunction, other malfunctions exhibit similar behavior in terms of voltage drop and temperature rise, requiring more detailed measurement techniques such as Electrochemical Impedance Spectroscopy to identify the cause of malfunctions. In addition, measuring the relative humidity of the outlet gas may not provide sufficient information to distinguish the malfunction of the anode or cathode humidifier. The results of the study suggest fault detection and isolation methods under these malfunction conditions to prevent more severe failure of the PEMFC stack and system. An extensive multi-dimensional contour comprising temperature, relative humidity, liquid saturation, water content, and current density is also provided for the better analyzation of system malfunctioning behaviors.

Математическая модель регулятора аксиально-поршневого насоса на примере HPV102GW-RH23A фирмы «Hitachi»

The purpose of the paper is to develop a mathematical model of the controller of the axial piston pump Hitachi HPV102GW-RH23A to determine the influence of controller parameters on pump output characteristics and carry out the mathematical modeling of controller operation. The mathematical model of the controller is developed. Its solution scheme in Matlab-Simulink is proposed. Displacements of the spool (x 1 ), servo piston (x 3 ) are determined as well as changes in the pressure from a large area of the servo piston (p 3 ) in time at a nominal pressure in the system and when p>p nom . The dependence of the servo piston displacement (x 3 ) on the spool spring stiffness is obtained. The developed mathematical model of the controller allows to find out the causes of malfunctions in the operation of the adjustable axial piston pump. Thus, an increase in the stiffness of the spool 1 spring by 5000 N/m decreases the servo piston displacement and, consequently, the pump flow by 20%. This reduces the load of the basic machine engine and causes the loss of excavator performance as a whole. The increase in the total stiffness of the springs of spool 6 in comparison with the nameplate data can lead to an overload of the excavator engine up to its complete stop.

Development of Mounting Bracket for CCS electronic unit of Armoured Fighting Vehicle

This paper describes the design and development of new mounting bracket replacing the old one. Commander Control station (CCS) is one of the accessories for the Armoured Fighting vehicle (AFV) sighting system and it is fitted on the mounting bracket in front of Commander’s station at turret roof plate of the AFV. It displays the thermal images of the Gunner’s main sight which is to monitor the Gunner Line of sight continuously by the Commander. During the trial, it was noticed that the existing CCS electronics units are malfunctioned. To know the cause of malfunction, it was planned to conduct the vibration analysis on the locations of CCS electronics units. Subsequently the level of vibration on all the locations were recorded and analyzed for various operating track profiles. The spectrum plot of CCS location for all these track profiles shows the overall vibration levels in the frequency band of 20- 2000Hz are well within the qualified limit. However the CCS electronics units show a resonance at 22.5 Hz in the lower frequency band where the amplitude is maximum may be of concern for electronic unit’s mal functionality. Hence a new CCS unit of light weight compact and durable is planned to retro fitment with the new modified compact mounting bracket on AFV. The mounting bracket is designed in such a way that the natural frequency of the same bracket to be away from 0-100Hz. This is achieved, by carrying out, Structural, Shock and Response Spectrum analysis.

Development of a building continuity support system as building management system for business continuity—Fundamental research on implementation of resilient buildings

AbstractThe resilience of buildings can be improved by revising the methods of building management. This paper discusses the development of a new building management system for continuity of important operations. In the early stages after a disaster, it is important to assess what happened, the actual conditions, whether important operation spaces can be used, the causes of malfunctions, and what should be done to achieve continuity or early restoration of functions. This report presents a methodology to support the process of systematically confirming the actual conditions, judgment, adjustment, and actions for the building manager.

Ocena eksploatacyjnego zużycia wtryskiwaczy na podstawie analizy optycznej rozpylenia paliwa

The diagnostics of combustion engine components currently requires the integration of many technical and scientific fields in order to quickly and accurately locate faults or pinpoint the causes of malfunction. This article analyzes the wear of injectors based on the geometric indicators of the fuel spray. Using a number of available parameter data, a selection has been made to best judge the wear of injectors in their operating conditions. Optical fuel spray tests were used to assess the injector wear. Various geometric indicators of the fuel stream have been presented, indicating their diagnostic utility and applicability. In conclusion, it was found that the current injection systems require the combination of mechanical injector diagnostics and advanced optical fuel spray diagnostics.

An Intelligent Gear Fault Diagnosis Methodology Using a Complex Wavelet Enhanced Convolutional Neural Network

As a typical example of large and complex mechanical systems, rotating machinery is prone to diversified sorts of mechanical faults. Among these faults, one of the prominent causes of malfunction is generated in gear transmission chains. Although they can be collected via vibration signals, the fault signatures are always submerged in overwhelming interfering contents. Therefore, identifying the critical fault’s characteristic signal is far from an easy task. In order to improve the recognition accuracy of a fault’s characteristic signal, a novel intelligent fault diagnosis method is presented. In this method, a dual-tree complex wavelet transform (DTCWT) is employed to acquire the multiscale signal’s features. In addition, a convolutional neural network (CNN) approach is utilized to automatically recognise a fault feature from the multiscale signal features. The experiment results of the recognition for gear faults show the feasibility and effectiveness of the proposed method, especially in the gear’s weak fault features.

Smart building management vs. intuitive human control—Lessons learnt from an office building in Hungary

Smart building management and control are adopted nowadays to achieve zero-net energy use in buildings. However, without considering the human dimension, technologies alone do not necessarily guarantee high performance in buildings. An office building was designed and built according to state-of-the-art design and energy management principles in 2008. Despite the expectations of high performance, the owner was facing high utility bills and low user comfort in the building located in Budapest, Hungary. The objective of the project was to evaluate the energy performance and comfort indices of the building, to identify the causes of malfunction and to elaborate a comprehensive energy concept. Firstly, current building conditions and operation parameters were evaluated. Our investigation found that the state-of-the-art building management system was in good conditions but it was operated by building operators and occupants who are not aware of the building management practice. The energy consumption patterns of the building were simulated with energy modelling software. The baseline model was calibrated to annual measured energy consumption, using actual occupant behaviour and presence, based on results of self-reported surveys, occupancy sensors and fan-coil usage data. Realistic occupant behaviour models can capture diversity of occupant behaviour and better represent the real energy use of the building. This way our findings and the effect of our proposed improvements could be more reliable. As part of our final comprehensive energy concept, we proposed intervention measures that would increase indoor thermal comfort and decrease energy consumption of the building. A parametric study was carried out to evaluate and quantify energy, comfort and return on investment of each measure. It was found that in the best case the building could save 23% of annual energy use. Future work includes the follow-up of: occupant reactions to intervention measures, the realized energy savings, the measurement of occupant satisfaction and behavioural changes.

Biomimetic Bubble-Repellent Tubes: Microdimple Arrays Enhance Repellency of Bubbles Inside of Tubes.

The adhesion of bubbles underwater remains the greatest cause of malfunctions in applications such as microfluidics, medical devices, and heat exchangers. Recently, the combination of oxidization and peeling the top layer of self-organized honeycomb films with an adhesive tape resulted in the formation of an ultra-bubble-repellent and pillared polymer surface structure. However, the fabrication of honeycomb films on the inner surface of tubes and the formation of structured hydrophilic textures by peeling the top layer of honeycomb films still remain problematic. In this report, a simple fabrication technique for producing a honeycomb-patterned polymer film on the interior of a tube by dip-coating a polymer solution and blowing humid air in the tube is described. Furthermore, an ultra-bubble-repellent dimple-arrayed structure was fabricated by applying ultrasonication to the honeycomb structure formed on the interior surface of the tubes.

Improving technical maintenance of systems of mini hydropower plants: Analysis of causes of malfunctions, faults, failures and system failures

The paper presents many years of experience related to the activities of technical maintenance of mechanical and electrical plants. It shows the analysis of the cause of many malfunctions, faults, failures and system failures that occur in mini hydropower plants. Systems of mini hydropower plants are discussed in terms of improving the technical maintenance by functional units: turbine regulator with turbine, mechanical assemblies (multiplier and flywheel), flexible couplings that connect plant assemblies, electrical circuits, lubrication systems, automation and high-voltage installations. Below is a brief overview of the application possibilities of technical diagnostics i.e. of a monitoring system in mini hydropower plants.

A study of main causes of malfunction and breakdown for PV inverter and suggestion of some practical measures

The inverters and modules are main components of solar power plants. If any one of them is failure, result will affect the production of electricity. Through the literatures survey, it is found that the inverter among the lots of parts of the solar power plant occupy the largest portion of the fault, and the failure and malfunction of the inverter are caused by the conductive surges induced through the power system. Based on these results, authors analyzed power disturbance factors and results were compared with IEC international standards. Finally, some practical measures applicable in designing and construction grid tied PV power plant in Uzbekistan were suggested.

PROBLEMS OF TERMINOLOGY AND THE SUBJECTIVE FACTORS IN THE STUDY OF THE ICE FAILURES AND THEIR ROLE IN THE PROPER IDENTIFICATION OF THE CAUSES OF MALFUNCTIONS

Provides a common approach to the use of standards and normative technical documentation in the study and description of the causes of faults ICE, including an analysis of the contradictions in the terminology established by the various standards and regulations, as well as the impact of these conflicts on the results of studies on the causes of malfunctions. Case studies reviewed types of workmanship ICE, the most difficult identified in research. The analysis of the impact of subjective factors on the identification of the causes of manufacturing defects and showing the most common errors that prevent receipt of valid research results. Based on practical experience and recommendations on the application of the standards and normative and technical documentation in the study of the causes of ICE failures related to production defects.

A malfunctioning nasogastric feeding tube.

A critical point of nasogastric feeding tube placement, potentially resulting in an unsafe and/or non-effective operation of the device, is the monitoring of its proper placement into the stomach. A properly obtained and interpreted radiograph is currently recommended to confirm placement. We reported the case of a 68-year-old demented woman referred for complicated dysphagia. A nasogastric tube was blindly inserted and its placement was confirmed by the radiologist. Enteral nutrition was initiated but the patient began to vomit immediately. After reviewing the radiograph it was understood that a gastric loop in the tube and its tip pointing upwards did not allow a safe infusion of the feeding formula. It is not enough having the radiologist reporting that a nasogastric feeding tube is placed in the stomach; the inclusion in the report of specific warnings on any potential cause of malfunctioning of the device should be considered. The presence of a gastric loop should be taken into account as a cause of potential malfunctioning.

Malfunction diagnosis method for the thermal system of a power plant based on thermoeconomic analysis

ABSTRACTIt is difficult to accurately diagnose and locate faults in the thermal system of power plants due to the coupling of multiple components. The goal of the current study is to develop a model that predicts how the thermodynamic parameters–performance curve is changed when one component exhibits anomalies. This model uses the concept of irreversibility in thermoeconomic structure theory as a means of quantitatively measuring changes in the performance of power plant thermal systems. This is achieved by initially filtering out the effect of anomalies on the control regulation system and subsequently comparing the change in performance to reference values, enabling qualitative analysis to decouple component interactions. Following model construction, advanced process simulation is applied to simulate several typical fault conditions in a 330-MW power plant, and the proposed model is used to diagnose the cause of malfunction based on thermoeconomic analysis. The results indicate that the method has satisfactory feasibility for malfunction diagnosis in a complex energy system.

Wireless Sensors System for Broken Rotor bar Fault Monitoring using Wavelet Analysis

Accurate condition monitoring prevents unexpected failures in electrical systems including induction machines, and hence improves their performance significantly. To enhance the reliability of condition monitoring systems, wireless sensor systems are developed. In the recent years, researchers have placed considerable emphasis on developing cost-effective scheme using wireless sensor systems for fault diagnosis of equipments in industry. As broken rotor bar is one of the main causes of malfunction in electrical motors, this paper proposes a method for early detection of this failure in induction machines using wireless sensor system. In this respect, a test bed is developed where a sensor measures the motor current and then a microcontroller connected to this current sensor read and send the data to wireless sensor for remote real time data analysis. In the receiver unit, a Lab VIEW based program is developed to store data in a database and MATLAB is used for signal processing and fault.

An industry survey of the screw press system in palm oil mills: Operational data and malfunction issues

Research questionnaires were disseminated to active palm oil mills across Malaysia to acquire information on (i) the mill operation, and (ii) any malfunction issues concerning the screw press system. A total of 105 mills responded to the survey (response rate=25%). The relationship between the mill operational data (processing capacity, daily operation cycle), the screw press system (type, quantity), and the malfunction frequency was examined. The double screw press machine dominated the palm oil milling industries due to its larger capacity that entails a shorter processing time in comparison with the single screw press. Recurring malfunction problems were prevalent in both types of screw press system. While fatigue, corrosion, wear and tear are inevitable due to the heavy usage and natural causes, an irregular maintenance schedule and poor handling topped the list of common cause for malfunction of the screw press.

A comparison of feature ranking techniques for fault diagnosis of ball bearing

In rotating machinery one of the prominent causes of malfunction is faults generated in ball bearings, therefore, diagnosis and interpretation of these faults is essential before they become severe. Feature extraction methodology has been presented in this paper based on application of lifting wavelet transform. Minimum permutation entropy is considered as decision making for selecting level of lifting wavelet transform. Sixteen features are calculated from measured vibration signals for various bearing conditions like defect in inner race, outer race, ball defect, combined defect and no defect condition. To achieve better fault identification accuracy selection of features carrying useful information is needed. To select highly distinguished features various ranking methodologies such as Fisher score, ReliefF, Wilcoxon rank, Gain ratio and Memetic feature selection are used. The ranked feature sets that are fed to machine learning algorithms support vector machine, learning vector quantization and artificial neural network for identification of bearing conditions. Tenfold cross-validation results show that selected features give enhanced accuracy for detecting faults. Features selected through Fisher score-support vector machine and ReliefF-artificial neural network gives 100 % cross-validation accuracy. Result shows that proposed methodology is feasible and effective for fault diagnosis of bearing with reduced feature set.

Genes and Podocytes – New Insights into Mechanisms of Podocytopathy

After decades of primarily morphological study, positional cloning of the NPHS1 gene was the landmark event that established aberrant podocyte genetics as a pivotal cause of malfunction of the glomerular filter. This ended any uncertainty whether genetic mutation plays a significant role in hereditary nephrotic syndromes (NS) and confirmed podocytes as critical players in regulating glomerular protein filtration. Although subsequent sequencing of candidate genes chosen on the basis of podocyte biology had less success, unbiased analysis of genetically informative kindreds and syndromic disease has led to further gene discovery. However, the 45 genes currently associated with human NS explain not more than 20–30% of hereditary and only 10–20% of sporadic cases. It is becoming increasingly clear both from genetic analysis and phenotypic data – including occasional response to immunosuppressive agents and post-transplant disease recurrence in Mendelian disease – that monogenic inheritance of abnormalities in podocyte-specific genes disrupting filter function is only part of the story. Recent advances in genetic screening technology combined with increasingly robust bioinformatics are set to allow identification and characterization of novel disease causing variants and more importantly, disease modifying genes. Emerging data also support a significant but incompletely characterized immunoregulatory component.

Radiography of cardiac conduction devices: a pictorial review of pacemakers and implantable cardioverter defibrillators.

Cardiac conduction devices (CCDs) depend on correct anatomic positioning to function properly. Chest radiography is the preferred imaging modality to evaluate CCD's anatomic location, lead wire integrity, and help in identifying several complications. In this pictorial review, our goal is to familiarize radiologists with CCD implantation techniques, appropriate positioning of the device, common causes of malfunction, methods to improve report accuracy, and assure maximal therapeutic benefit.