Mujer, salud y medio ambiente

Las diferencias de salud entre las mujeres y hombres han sido estudiadas en abundantes estudios, principalmente epidemiológicos, existiendo numerosas evidencias empíricas que demostrarían que las mujeres sufren, con mayor prevalencia que los hombres, ciertas enfermedades, acuden más veces a las consultas médicas y consumen más especialidades farmacéuticas que los hombres. El objetivo de este artículo es analizar cómo la salud de las mujeres se ve influida por las condiciones medioambientales. Se trataría de estudiar la posible presencia de una conexión entre el entorno medioambiental y la salud de las mujeres y comprobar si existe una construcción social de género en relación con la salud y la enfermedad.______________________________The differences in health between women and men have been analyzed in several studies (mainly epidemiological studies) which offer enough empirical evidence to demonstrate that women sufferfrom certain illnesses much more than men, go and see the doctor more often than men, and consume more medicines than men. The aim of the article is to analyze how women's health is influenced by environmental conditions. On the one hand, the article aims at studying the possible existence of a link between the environmental surroundings and women's health. On the other hand, it aims at finding out if there exists a social construction of gender in relation to health and illness

Investigation of vibrational behavior of friction pair under starved lubrication conditions

The paper presents results of measurements of radial vibrations of steel friction pair "rotating roller – fixed segment" under starved and amply lubricated boundary lubrication conditions. Experiments were conducted on computerized tribometer, the friction pair was lubricated with mineral motor oil. Vibrations were measured by means of accelerometer attached to the loaded element of friction pair – segment. Results are presented as vertical vibration spectra of segment versus lubrication mode and loa

Investigation Into Levitating Polishing Disc Used for Flat Surface Finishing

The paper presents a new type of flat surface polishing device. The polishing disc rotates using the pressure of compressed air. The polishing disc has a special geometry, wherein it has holes for flow turbulence minimisation in the air pressure areas of the boundary. The influence of the hole inclination angle on the rotational speed of the disk and the system efficiency was studied experimentally and numerically. It was established that the optimal inclination angle is a 20° angle that results in the maximum efficiency of the proposed system. In the experiment, three polishing discs with hole inclination angles of 0°, 20°, and 30° were studied; the discs were rotated using four air pressure values: 0.2, 0.3, 0.4, and 0.5 MPa. It was found that the optimal inclination angle of holes was 20° and that the fastest rotational speed, i.e. 1900 1/min, was reached at a maximum air pressure of 0.5 MPa

The Analysis of Vibration Signals of Critical Points of the Bus Body Frame

In this paper, authors have investigated wave distribution caused by the mechanical structure of a passenger bus body frame and its parameters based on the theory of covariance functions. Authors have measured the intensity of vibrations at fixed points. Time scale analyses were conducted based on data arrays (matrixes). The estimates of covariance functions clearly showed that changes in the state of the bus mechanical structure invariably impact changes of the intensity of vibration signals at the relevant points. In the analysis, software Matlab 7 was applied

Investigation of vibrational behavior of friction pair under starved lubrication conditions

The paper presents results of measurements of radial vibrations of steel friction pair "rotating roller – fixed segment" under starved and amply lubricated boundary lubrication conditions. Experiments were conducted on computerized tribometer, the friction pair was lubricated with mineral motor oil. Vibrations were measured by means of accelerometer attached to the loaded element of friction pair – segment. Results are presented as vertical vibration spectra of segment versus lubrication mode and loa

Bidirectional Piezoelectric Energy Harvester

This paper represents a numerical and experimental investigation of the bidirectional piezoelectric energy harvester. The harvester can harvest energy from the vibrating base in two perpendicular directions. The introduced harvester consists of two cantilevers that are connected by a particular angle and two seismic masses. The first mass is placed at a free end of the harvester while the second mass is fixed at the joining point of the cantilevers. The piezoelectric energy harvester employs the first and the second out of plane bending modes. The numerical investigation was carried out to obtain optimal geometrical parameters and to calculate the mechanical and electrical characteristics of the harvester. The energy harvester can provide stable output power during harmonic and impact-based excitation in two directions. The results of the investigations showed that energy harvester provides a maximum output power of 16.85 µW and 15.9 4 µW when the base has harmonic vibrations in y and z directions, respectively. Maximum output of 4.059 nW/N and 3.1 nW/N in y and z directions were obtained in case of impact based excitationThis article belongs to the Special Issue Energy Harvesting and Energy-Neutral IoT Devices and SystemsThis project has received funding from the European Regional Development Fund (project No 01.2.2-LMT-K-718-01-0010) under a grant agreement with the Research Council of Lithuania

Efficient hydrotreated vegetable oil combustion under partially premixed conditions with heavy exhaust gas recirculation

This study performed a detailed analysis of combustion and emission characteristics of a single-cylinder compression ignition engine fuelled with diesel, hydrogenated vegetable oil (HVO) and their blend (50/50). Taking advantage of the high reactivity of HVO, the aim was to investigate how changes in fuel injection and exhaust gas recirculation (EGR) strategies can achieve partially premixed combustion with superior efficiency and ultra-low engine-out emissions. Without EGR, and with a multi-pulse injection strategy optimized for diesel, combustion timings were the same for all three investigated fuels. HVO exhibited higher tolerance to EGR in terms of combustion retarding, so it was possible to use high recirculation rates. This reduced nitrogen oxides, while maintaining high indicated efficiency. The pilot injection control allowed further extending the EGR dilution limit without incurring trade-offs with combustion efficiency and related carbon monoxide and unburned hydrocarbon emissions. Additionally, heavy EGR conditions supported reduction of soot for all three tested fuels. However, the best trade-off between soot and other emission compounds was observed for HVO. HVO also resulted in the lowest emissions of aldehydes and aromatics. In conclusion, on the given engine platform at a steady-state, mid-load operating point, HVO allowed for 43% indicated thermal efficiency with engine-out nitrogen oxides and carbon monoxide emissions near to Euro VI limits. This efficiency level was 1.5 percentage points above that for the optimized diesel operation.fi=vertaisarvioitu|en=peerReviewed

Modal analysis and experimental research into improved centering-leveling devices

Centering–leveling devices are often used together with rotary tables to improve measuring process in various fields of metrology. The most important factor of measurement quality – accuracy – is affected by numerous external and internal factors. To ensure the optimum quality of measurements, several factors have to be well known and thus taken into account in the final measurement to minimize their influence. Analysis of structural dynamics provides data on sensitivity as well as an appropriate method to verify the analytical model. The paper deals with an analysis of structural dynamics of a plain structure centering–leveling device by performing appropriate modal analysis. The experimental setup for vibration monitoring and measurement principle underpinning the work is described in the paper. Measurement results of table dynamics as well as a comparison of theoretical and experimental modal shapes are discussed

An Investigation Into Fault Diagnosis in a Rotor-Bearing System with Dampers Used in Centrifugal Milk Separators

This paper deals with the problems encountered in the fault diagnosis in damped rotor-bearing systems used in centrifugal milk separators. It is shown that direct bearing vibration measurements are more reliable than indirect (through rotor housing) vibration measurements. However, in most cases it is not possible to measure bearing vibrations directly. The factors causing large diagnostic measurement errors, such as the influence of the vibration damping system, step-up gear and electric motor noise are discussed in the paper. It is established that vibration measurements of the damping system are noninformative and cannot be used to diagnose faults in bearings. It is proposed to use the vibration spectra correlation to predict bearing failures in rotor-bearing systems of this type

The Influence of Different Loads on the Footbridge Dynamic Parameters

Bringing together the experience and knowledge of engineers allowed building modern footbridges as very slender structures. This in turn has led to structural vibration problems, which is a direct consequence of slender structures. In some footbridges, this problem occurs when natural construction frequencies are close to excitation frequencies. This requires a design methodology, which would ensure user safety and convenience of use of the footbridge in operation. Considering the aforementioned dynamic response, the analysis of the finite element model of a footbridge was conducted focusing on critical acceleration and deformation meanings. The model was based on the footbridge prototype located in Vilnius, Lithuania. Two different loading methods were developed to investigate the dynamic effects caused by people crossing a footbridge. The comparison of experimental and finite element model (FEM) results revealed that the footbridge in operation is within the limit values of comfort requirements in terms of its vibrations