Behavior of an IC Engine Turbocharger in Critical Conditions of Lubrication

Problems in the turbocharger lubrication system can cause serious deterioration in their overall performance and even their complete destruction. The paper describes several tests with different critical lubrication conditions, in order to determine the thresholds at which the operation may be appropriate. In an IC engine, these problems can be produced mainly by several factors: the decreasing in the supply pressure of the oil, a delay in the lubrication oil pressure and an intermittent lubrication interruption. A turbocharger test bench and an IC engine test bench has been used to test the turbocharger, in order to reproduce the conditions and cycles similar to the operation of the turbocharger in an IC engine (pressures, temperatures, mass flows, accelerations, etc..). Thermodynamic variables and mechanic variables measured in the tests help to identify some of the operating limits of lubrication in critical conditions. In addition, optical techniques have been combined with accelerometer measurements, in order to detect modifications in the movement of the turbocharger shaft. The main conclusions obtained from these tests are that accelerations from low rotational speed to 100krpm, without lubrication oil in the bearing system, don’t cause significant problems in the turbocharger, for 20 sec. However, the accelerations to 150krpm can cause critical problems depending on the lubrication delay and the bearing configuration. Finally, higher acceleration rates to 200krpm, without lubrication, cause the turbocharger destruction in a few seconds. By other hand, a low oil inlet pressure given by an oil column, of about 1m in height, allows to the turbo survive during accelerations from low rotational speed to 150 krpm.Galindo, J.; Serrano Cruz, JR.; Dolz Ruiz, V.; López Hidalgo, MA.; Bouffaud, F. (2013). Behavior of an IC Engine Turbocharger in Critical Conditions of Lubrication. SAE International Journal of Engines. 6(2):1-9. doi:10.4271/2013-01-0921S196

Study of turbocharger shaft motion by means of non-invasive optical techniques: Application to the behaviour analysis in turbocharger lubrication failures

[EN] This paper presents a novel non-invasive technique to estimate the turbocharger shaft whirl motion. The aim of this article is to present a system for monitoring the shaft motion of a turbocharger, which will be used in turbocharger destructive testing. To achieve this, a camera and a light source were installed in a turbocharger test bench with a controlled lubrication circuit. An image recording methodology and a process algorithm have been developed, in order to estimate the shaft motion. This processing consists on differentiating specific zones of the image, in order to obtain their coordinates. Two reference points have been configured on the compressor side, which help to calculate the relative position of the shaft, avoiding the errors due to structural vibrations. Maximum eccentricity of the turbocharger has been determined and it has been compared with shaft motion when it is spinning in different conditions. A luminosity study has been also done, in order to improve the process and to obtain locus of shaft position in a picture exposition time period. The technique has been applied to diagnosis of a lubrication failure test and the main results will be presented in this article: like shaft motion figures; thermodynamic variables and pictures of the shaft while it is spinning at abnormal lubrication conditions. The measuring components used in this technique have the ability to withstand the catastrophic failure of the turbocharger in this type of test. © 2012 Elsevier Ltd.Pastor, JV.; Serrano, J.; Dolz, V.; López Hidalgo, M.; Bouffaud, F. (2012). Study of turbocharger shaft motion by means of non-invasive optical techniques: Application to the behaviour analysis in turbocharger lubrication failures. Mechanical Systems and Signal Processing. 32:292-305. doi:10.1016/j.ymssp.2012.04.020S2923053

The effect of postural freedom to increase the neutral positions during laparoscopic surgery

[EN] Laparoscopic technique has demonstrated numerous advantages compared to open conventional surgery. Nevertheless, this procedure increases the surgeons fatigue and thus, the potential to commit errors that may harm the patient during the operation. The post-surgery pain is also augmented because the surgeons are forced to adopt non-neutral postures during the practice. This study reveals how a postural freedom element could help surgeons to improve the postural hygiene. During this study, thirteen participants with and without previous experience in laparoscopic surgery performed a test with two instruments: a prototype that implement this postural freedom concept and a conventional fixed instrument. The results obtained indicate that the postural freedom element allows the participants to maintain neutral positions during greatest part of the experiment and suggest that the implementation of an articulated element could increases the neutral positions adopted during a real laparoscopic procedure. The use of the postural freedom concept allowed to the participants to reduce the awkward positions during upper limb motions and to reduce displacements, avoiding extreme abductions that are common with the conventional fixed instruments.Pace-Bedetti, HM.; Dolz, JF.; Martínez-De-Juan, JL.; Conejero Rodilla, A. (2019). The effect of postural freedom to increase the neutral positions during laparoscopic surgery. International Journal on Interactive Design and Manufacturing (IJIDeM). 13(2):627-631. https://doi.org/10.1007/s12008-018-00527-6S62763113

Study of the turbocharger shaft motion by means of infrared sensors

This work describes a technique for measuring the precession movement of the shaft of small automotive turbochargers. The main novelty is that the technique is based on infrared light diode sensors. With presented technique it is possible to perform secure mounting of electronics and also to measure, with good accuracy, far enough from the turbocharger shaft. Both advantages allow applying it even in critical lubrication conditions and when blade contact occurs. The technique's main difficulties arise from the small size of the turbocharger shaft and the high precession movement in critical conditions. In order to generate the optimum albedo reflection for infrared measurement, a special cylindrical nut with larger diameter than the original one is assembled at the shaft tip in the compressor side. Following, shaft balancing, the calibration of the sensors and the compensation of errors from different sources are needed steps before the method is able to identify the main frequencies of shaft motion. Once synchronous and sub-synchronous frequencies have been obtained it is possible to reconstruct the instantaneous position of the shaft to determine its precession movement.This research has also been partially supported by the Programa de Desarrollo del Talento Humano de la Secretaria Nacional de Educacion Superior, Ciencia, Tecnologia e Innovacion del Gobierno Ecuatoriano No. 20100289.Serrano Cruz, JR.; Guardiola, C.; Dolz García, VM.; López, M.; Bouffaud, F. (2015). Study of the turbocharger shaft motion by means of infrared sensors. Mechanical Systems and Signal Processing. 56-57:246-258. https://doi.org/10.1016/j.ymssp.2014.11.006S24625856-5

Analyzing the impact of the MPI allreduce in distributed training of convolutional neural networks

For many distributed applications, data communication poses an important bottleneck from the points of view of performance and energy consumption. As more cores are integrated per node, in general the global performance of the system increases yet eventually becomes limited by the interconnection network. This is the case for distributed data-parallel training of convolutional neural networks (CNNs), which usually proceeds on a cluster with a small to moderate number of nodes. In this paper, we analyze the performance of the Allreduce collective communication primitive, a key to the efficient data-parallel distributed training of CNNs. Our study targets the distinct realizations of this primitive in three high performance instances of Message Passing Interface (MPI), namely MPICH, OpenMPI, and IntelMPI, and employs a cluster equipped with state-of-the-art processor and network technologies. In addition, we apply the insights gained from the experimental analysis to the optimization of the TensorFlow framework when running on top of Horovod. Our study reveals that a careful selection of the most convenient MPI library and Allreduce (ARD) realization accelerates the training throughput by a factor of 1.2× compared with the default algorithm in the same MPI library, and up to 2.8× when comparing distinct MPI libraries in a number of relevant combinations of CNN model+dataset

Adapting concurrency throttling and voltage–frequency scaling for dense eigensolvers

We analyze power dissipation and energy consumption during the execution of high-performance dense linear algebra kernels on multi-core processors. On top of this analysis, we propose and evaluate several strategies to adapt concurrency throttling and the voltage–frequency setting in order to obtain an energy-efficient execution of LAPACK’s routine dsytrd. Our strategies take into account the differences between the memory-bound and CPU-bound kernels that govern this routine, and whether problem data fits into the processor’s last level cache.This work was supported by the CICYT Project TIN2011-23283 of MINECO and FEDER, the EU Project FP7 318793 “EXA2GREEN”, and the FPU program of the Ministerio de Educación, Cultura y Deporte

Pain coping strategies and quality of life in patients diagnosed of fibromyalgia

Objetivo: El objetivo de la investigación se centra en el estudio de las estrategias de afrontamiento utilizada por el paciente para hacer frente a su dolor, siendo definidas estas como los pensamientos y acciones que los individuos realizan en sus esfuerzos por manejar el dolor, y su repercusión sobre la calidad de vida del paciente. Material y métodos: La muestra del estudio está formada por 32 mujeres diagnosticadas de fibromialgia que acuden por primera vez al Servicio de Psicología de la Unidad Multidisciplinar del Dolor en el Consorcio Hospital General Universitario de Valencia previa exploración médica. Los pacientes completaron una batería de cuestionarios donde además de recoger las variables sociodemográficas (edad, sexo, estado civil, nivel de estudios), se evaluó el nivel de dolor informado a través del EVA (escala analógica visual), valoración del dolor (por ejemplo, "el dolor depende de mí", "puedo anticipar cuándo me va a doler"...), las estrategias de afrontamiento al dolor a partir del cuestionario de afrontamiento al dolor (CAD) y el cuestionario de calidad de vida ICV-2R. Resultados y conclusiones: A nivel descriptivo, los resultados muestran que las pacientes informan de un nivel de dolor moderadamente elevado, siendo las estrategias de afrontamiento al dolor más utilizadas, la autoafirmación y la búsqueda de información, y presentando un índice de calidad de vida inferior al de la población general. A nivel correlacional, no se ha encontrado ninguna relación significativa entre el índice general de calidad de vida y las estrategias de afrontamiento al dolor, aunque el uso de estrategias de afrontamiento más bien pasivas (como por ejemplo, la religión) se asocian significativa y positivamente con la dimensiones de calidad de vida que implican cierto grado de desadaptación por parte del paciente a la enfermedad, mientras que el uso de estrategias más activas ante el dolor (por ejemplo, distracción y autocontrol mental) se relacionan significativa y negativamente con dichas dimensionesObjective: The objective of this research focused on the study of coping strategies used by patients to face pain, these being defined as the thoughts and actions taken by individuals in their efforts to handle pain and their impact on the patient quality of life. Material and methods: The study population included 32 women diagnosed of fibromyalgia that attended for the first time the Psychology Service of the Multidisciplinary Pain Unit at the Consorcio Hospital General Universitario de Valencia prior medical examination. The patients completed a set of questionnaires that, in addition to obtain sociodemographic variables (age, sex, marital status, educational level), the following was assessed: pain severity determined using a VAS (visual analogic scale), pain valuation (for example, "pain depends on me", "I can anticipate when it is going to hurt"...), pain coping strategies based on the pain coping questionnaire (PCQ) and the quality of life questionnaire ICV-2R. Results and conclusions: At the descriptive level, the results show that the patients reported a moderately severe pain, being self-assertion and information seeking the pain coping strategies more frequently used. Furthermore, they presented a quality of life index lower than the general population. At the correlational level, no significant relationship has been found between the general quality of life index and the pain coping strategies, although the use of more passive coping strategies (such as religion) are significantly and positively associated to dimensions of quality of life that involve certain degree of maladjustment of the patient to the disease, while the use of more active pain coping strategies (such as distraction and mental self-control) are significantly and negatively associated to such dimensions.Psicologí

Renal Function Impact in the Prognostic Value of Galectin-3 in Acute Heart Failure

[Abstract] Introduction: Galectin-3 (Gal-3) is an inflammatory marker associated with the development and progression of heart failure (HF). A close relationship between Gal-3 levels and renal function has been observed, but data on their interaction in patients with acute HF (AHF) are scarce. We aim to assess the prognostic relationship between renal function and Gal-3 during an AHF episode. Materials and methods: This is an observational, prospective, multicenter registry of patients hospitalized for AHF. Patients were divided into two groups according to estimated glomerular filtration rate (eGFR): preserved renal function (eGFR ≥ 60 mL/min/1.73 m2) and renal dysfunction (eGFR <60 mL/min/1.73 m2). Cox regression analysis was performed to evaluate the association between Gal-3 and 12-month mortality. Results: We included 1,201 patients in whom Gal-3 values were assessed at admission. The median value of Gal-3 in our population was 23.2 ng/mL (17.3-32.1). Gal-3 showed a negative correlation with eGFR (rho = -0.51; p < 0.001). Gal-3 concentrations were associated with higher mortality risk in the multivariate analysis after adjusting for eGFR and other prognostic variables [HR = 1.010 (95%-CI: 1.001-1.018); p = 0.038]. However, the prognostic value of Gal-3 was restricted to patients with renal dysfunction [HR = 1.010 (95%-CI: 1.001-1.019), p = 0.033] with optimal cutoff point of 31.5 ng/mL, with no prognostic value in the group with preserved renal function [HR = 0.990 (95%-CI: 0.964-1.017); p = 0.472]. Conclusions: Gal-3 is a marker of high mortality in patients with acute HF and renal dysfunction. Renal function influences the prognostic value of Gal-3 levels, which should be adjusted by eGFR for a correct interpretation.Grant No. RD06-0003-0000 Grant No. RD12/0042/000

Risk factors associated with moderate-to-severe renal dysfunction among heart transplant patients: results from the CAPRI study

[Abstract] The longer survival of patients with heart transplantation (HT) favors calcineurin inhibitor–related chronic kidney disease (CKD). It behoves to identify risk factors. At 14 Spanish centers, data on 1062 adult patients with HT (age 59.2 ± 12.3 yr, 82.5% men) were collected at routine follow-up examinations. Glomerular filtration rate, GFR, was estimated using the four-variable MDRD equation, and moderate-or-severe renal dysfunction (MSRD) was defined as K/DOQI stage 3 CKD or worse. Time since transplant ranged from one month to 22 yr (mean 6.7 yr). At assessment, 26.6% of patients were diabetic and 63.9% hypertensive; 53.9% were taking cyclosporine and 33.1% tacrolimus; and 61.4% had MSRD. Among patients on cyclosporine or tacrolimus at assessment, multivariate logistic regression identified male sex (OR 0.44), pre- and post-HT creatinine (2.73 and 3.13 per mg/dL), age at transplant (1.06 per yr), time since transplant (1.05 per yr), and tacrolimus (0.65) as independent positive or negative predictors of MSRD. It is concluded that female sex, pre- and one-month post-HT serum creatinine, age at transplant, time since transplant, and immunosuppression with cyclosporine rather than tacrolimus may all be risk factors for development of CKD ≥ stage 3 by patients with HT

Smoking and age-related macular degeneration: review and update

Age-related macular degeneration (AMD) is one of the main socioeconomical health issues worldwide. AMD has a multifactorial etiology with a variety of risk factors. Smoking is the most important modifiable risk factor for AMD development and progression. The present review summarizes the epidemiological studies evaluating the association between smoking and AMD, the mechanisms through which smoking induces damage to the chorioretinal tissues, and the relevance of advising patients to quit smoking for their visual health