A Vibration Analysis for the Evaluation of Fuel Rail Pressure and Mass Air Flow Sensors on a Diesel Engine: Strategies for Predictive Maintenance

This research focuses on the analysis of vibration of a compression ignition engine (CIE), specifically examining potential failures in the Fuel Rail Pressure (FRP) and Mass Air Flow (MAF) sensors, which are critical to combustion control. In line with current trends in mechanical system condition monitoring, we are incorporating information from these sensors to monitor engine health. This research proposes a method to validate the correct functioning of these sensors by analysing vibration signals from the engine. The effectiveness of the proposal is confirmed using real data from a Common Rail Direct Injection (CRDi) engine. Simulations using a GT 508 pressure simulator mimic FRP sensor failures and an adjustable potentiometer manipulates the MAF sensor signal. Vibration data from the engine are processed in MATLAB using frequency domain techniques to investigate the vibration response. The results show that the proposal provides a basis for an efficient predictive maintenance strategy for the MEC engine. The early detection of FRP and MAF sensor problems through a vibration analysis improves engine performance and reliability, minimizing downtime and repair costs. This research contributes to the advancement of monitoring and diagnostic techniques in mechanical engines, thereby improving their efficiency and durability.

Dynamics and Embedded Internet of Things Input Shaping Control for Overhead Cranes Transporting Multibody Payloads

Input shaping is an Optimal Control feedforward strategy whose ability to define how and when a flexible dynamical system defined by Ordinary Differential Equations (ODEs) and computer controlled would move into its operative space, without command induced unwanted dynamics, has been exhaustively demonstrated. This work examines the issue of Embedded Internet of Things (IoT) Input Shaping with regard to real time control of multibody oscillatory systems whose dynamics are better described by differential algebraic equations (DAEs). An overhead crane hanging a double link multibody payload has been appointed as a benchmark case; it is a multibody, multimode system. This might be worst scenario to implement Input Shaping. The reasons can be found in the wide array of constraints that arise. Firstly, the reliability of the multibody model was tested on a Functional Mock-Up Interface (FMI) with the two link payload suspended from the trolley by comparing the experimental video tapping signals in time domain faced with the signals extracted from the multibody model. The FFTs of the simulated and the experimental signal contain the same frequency harmonics only with somewhat different power due to the real world light damping in the joints. The application of this approach may be extended to other cases i.e., the usefulness of mobile hydraulic cranes is limited because the payload is supported by an overhead cable under tension that allows oscillation to occur during crane motion. If the payload size is not negligible small when compared with the cable length may introduce an additional oscillatory mode that creates a multibody double pendulum. To give the insight into the double pendulum dynamics by Lagrangian methods two slender rods as payloads are analyzed dealing with the overhead crane and a composite revolute-revolute joint is proposed to model the cable of the hydraulic crane, both assumptions facilitates an affordable analysis. This allows developing a general study of this type of multibody payloads dynamics including its normal modes, modes ratios plus ranges of frequencies expected. Input Shapers were calculated for those multimodes of vibration by convolving Specified Insensitivity (SI) shapers for each mode plus a novel Direct SI-SI shaper well suited to reduce the computational requirements, i.e., the number of the shaper taps, to carry out the convolution sum in real time by the IoT device based on a single microcontroller working as the command generator. Several comparisons are presented for the shaped and unshaped responses using both the multibody model, the experimental FMI set-up and finally a real world hydraulic crane under slewing motion commanded by an analog Joystick connected by two RF modules 802.15.4 to the IoT device that carry out the convolution sum in real time. Input Shaping improves the performances for all the cases.

EMD-Based Methodology for the Identification of a High-Speed Train Running in a Gear Operating State

An efficient maintenance is a key consideration in systems of railway transport, especially in high-speed trains, in order to avoid accidents with catastrophic consequences. In this sense, having a method that allows for the early detection of defects in critical elements, such as the bogie mechanical components, is a crucial for increasing the availability of rolling stock and reducing maintenance costs. The main contribution of this work is the proposal of a methodology that, based on classical signal processing techniques, provides a set of parameters for the fast identification of the operating state of a critical mechanical system. With this methodology, the vibratory behaviour of a very complex mechanical system is characterised, through variable inputs, which will allow for the detection of possible changes in the mechanical elements. This methodology is applied to a real high-speed train in commercial service, with the aim of studying the vibratory behaviour of the train (specifically, the bogie) before and after a maintenance operation. The results obtained with this methodology demonstrated the usefulness of the new procedure and allowed for the disclosure of reductions between 15% and 45% in the spectral power of selected Intrinsic Mode Functions (IMFs) after the maintenance operation.

Unravelling the tunable exchange bias-like effect in magnetostatically-coupled two dimensional hybrid (hard/soft) composites

Hybrid 2D hard-soft composites have been fabricated by combining soft (Co73Si27) and hard (NdCo5) magnetic materials with in-plane and out-of-plane magnetic anisotropies, respectively. They have been microstructured in a square lattice of CoSi anti-dots with NdCo dots within the holes. The magnetic properties of the dots allow us to introduce a magnetostatic stray field that can be controlled in direction and sense by their last saturating magnetic field. The magnetostatic interactions between dot and anti-dot layers induce a completely tunable exchange bias-like shift in the system's hysteresis loops. Two different regimes for this shift are present depending on the lattice parameter of the microstructures. For large parameters, dipolar magnetostatic decay is observed, while for the smaller one, the interaction between the adjacent anti-dot's characteristic closure domain structures enhances the exchange bias-like effect as clarified by micromagnetic simulations.

Molecular analysis of p53 tumor-suppressor gene and microsatellites in preneoplastic and neoplastic lesions of the colon and esophagus

Mutations in exons 4-8 of the p53 gene by the PCR-SSCP analysis in preneoplastic and neoplastic lesions of the colon (n=11) and esophagus (n=18) were screened. p53 overexpression by immunohistochemistry in 11 colonic lesions and 13 microsatellites, in all the patients (n=29), were also studied. A positive result concordancy between the three techniques was found in 1 adenoma and 2 adenocarcinomas of the colon, each with loss of heterozygocity of microsatellites. Metaplastic lesions of esophagus showed biallelic mutations and low frequency of microsatellite alterations. The relationship between genetic alterations in p53, microsatellites and type of colon and esophageal lesions is discussed.

Production of platelet-derived growth factor by human lung cancer

The production of platelet-derived growth factor (PDGF) was studied in small cell lung carcinoma, lung squamous carcinoma and lung adenocarcinoma cell lines, and in seven human lung tissues obtained from each type of lung cancer. By indirect immunofluorescence, PDGF was detected in all the cell lines. Likewise, five out of seven biopsies derived from patients with adenocarcinoma and squamous carcinoma, and four out of seven specimens with small cell carcinoma displayed a positive pattern for PDGF. In addition, lung carcinoma cell lines expressed both PDGF-A and PDGF-B/sis genes, as judged by Northern blot analysis. Biologically active, serum-free conditioned media obtained from all three cell lines stimulated the incorporation of [3H]thymidine into quiescent BALB/c-3T3 cells. This effect was abolished when IgG-PDGF antiserum was used. These findings suggest that an abnormal expression of PDGF occurs in the three more frequent types of lung cancer, which can play a potential role in neoplastic transformation and uncontrolled cell growth.

Adenosine deaminase in the diagnosis of tuberculous pleural effusions. A report of 218 patients and review of the literature

The activity of adenosine deaminase in the pleural fluid of 218 consecutive patients was studied. According to the etiology of exudative pleural effusions, the patients were divided into the following five groups: (1) tuberculosis; (2) lung cancer; (3) pneumonias; (4) miscellaneous; and (5) idiopathic. Patients with pleural tuberculosis presented significantly higher ADA activity than patients with nontuberculous pleural effusions (p less than 0.0001). The results indicated that in a population with a relatively high prevalence of tuberculosis, the analysis of ADA levels in pleural effusions constitutes a useful marker for the diagnosis which, in addition, can be made quickly and cheaply. Additionally, a comprehensive review of the literature on the role of ADA in the diagnosis of tuberculous pleural effusions is presented.

Tuberculosis of the larynx: clinical aspects in 19 patients

Laryngeal tuberculosis continues to exist in spite of extensive tuberculosis eradication campaigns. We present 19 cases of laryngeal tuberculosis seen in our institution between 1982 and 1987. From the clinical findings it is clear that the localization of the lesions has changed since the preantibiotic era. Today the spread appears to be mainly via lymphatic and hematogenic routes, as opposed to the direct spread more common previously. The fibrosis caused by the lesions is incapacitating and frequently requires surgical correction.