Biofuels and noise in tractor engines

Transport is included among the most important noise sources due to continuous increasing number of vehicles. In order to comply with the European regulations related to both the presence of renewable origin basedfuels and pollution (air and noise) reduction, biodiesel emerges as an excellent alternative. Provided that biodiesel properties are closely correlated with the chemical composition of the raw material used to produce it, this PhD thesis aims to study the effect of the chemical composition on air and noise emissions to find out the “ideal” raw material to produce biodiesel. Moreover, to study the effect of biodiesel on noise emission different models of sound prediction were developed. Finally, the influence of biodiesel chemical composition on sound quality has been assessed. The thesis comprises five chapters. First chapter presents an introduction to the PhD thesis, where the study purpose and objectives are stated and justified. Second chapter focuses on the effect of biodiesel chemical properties on combustion and air and noise emissions. In chapter 3, to predict noise emissions and their relation with the percentage of biodiesel blended with diesel fuel, two ANN-based models considering saturated and monounsaturated fatty acid methyl esters are presented. In addition, several response surface models have been developed to show the relationship between biodiesel chemical properties and noise emission by means of simple models, as well as the trend of the exhaust emissions and noise radiated for different engine operating conditions. Chapter 4 is composed of three evaluations of substitution monopole models for engine noise sound synthesis: the first work is based on Airborne Source Quantification (ASQ) technique, improved by means of regularization strategies. In the second evaluation, a novel model based on Product Unit Neural Networks (PUNN) is proposed and compared to ASQ technique. In the third evaluation, to improve the results achieved with the PUNN-based model, an ensemble of evolutionary Product Unit (PU) and Radial Basis Function (RBF) Neural Networks is suggested. In the fifth chapter, the effect of biodiesel properties on the tractor cabin mock up comfort from the driver’s point of view has been studied. Moreover, several response surface models have been developed to correlate different sound quality metrics with biodiesel chemical properties. Finally, a conclusions section, the proposal of future research lines and the compendium of references used in this PhD thesis are provided.Una de las principales fuentes de ruido la proporciona el transporte, debido al constante crecimiento del número de vehículos. Para cumplir con los objetivos establecidos por la UE relativos tanto al incremento del uso de energías renovables como a la reducción de emisiones contaminantes (gaseosa y acústica), el biodiésel surge como una excelente alternativa. Puesto que las propiedades del biodiésel están correlacionadas con la composición química de los aceites vegetales empleados, en esta tesis doctoral se ha estudiado el efecto de aquélla sobre las emisiones, con el objeto de encontrar la composición ideal para producir biodiésel. Además, se han desarrollado distintos modelos de predicción de ruido para comprobar el efecto del incremento del porcentaje de biodiésel en mezclas con gasóleo sobre el ruido emitido. La influencia de la composición química sobre la calidad del sonido también se ha analizado. De este modo, la tesis se compone de cinco capítulos. El primer capítulo presenta una introducción de la tesis doctoral, donde se muestran, justificadamente, los objetivos a alcanzar. El segundo capítulo estudia el efecto de la composición química del biodiésel sobre las emisiones contaminantes y el ruido emitido. En el capítulo tres, se desarrollan dos modelos de predicción de ruido basados en redes neuronales considerando biodiésel o ésteres metílicos de ácidos grasos de dos tipos, con alto grado de saturación y monoinsaturados. Además, se proponen varios modelos de predicción de ruido basados en propiedades y emisiones contaminantes del biodiésel. El capítulo cuatro se compone de la evaluación de modelos de fuentes de ruido en vehículos mediante distintas técnicas: primero por el método de cuantificación de fuentes aéreas (Airborne Source Quantification (ASQ)) con estrategias de regularización. La segunda técnica propuesta se basa en el empleo de redes neuronales para altas frecuencias y ASQ para bajas y medias frecuencias, siguiendo el comportamiento del sistema. Finalmente, en la tercera evaluación, se propone una mejora del método previo mediante la fusión de dos métodos de redes neuronales artificiales basados en Unidades Producto Evolutivas y Funciones de Base Radial. En el capítulo cinco, se estudia el efecto de las propiedades del biodiésel en el confort de la cabina de un tractor, desde el punto de vista del conductor. Este estudio se acompaña del desarrollo de modelos de predicción de parámetros de calidad del sonido, sonoridad (loudness) y aspereza (roughness), basados en propiedades del biodiésel. Finalmente, se ha incluido una sección de conclusiones generales, futuras líneas de investigación y un compendio de las referencias empleadas en esta tesis doctoral

Study of Sound Perception Evaluation in Refrigeration Gases

In the past, sound design was focused on the minimization of the emitted sound, understanding that the lower the sound, the better. Nowadays, this concept is outdated; in addition to the sound pressure level, many more aspects of the sound are considered to fulfil the subjective satisfaction of clients. Thus, a new concept called sound quality has emerged to reach more facets of the sound. In refrigeration systems, the recommendations of European Union are aimed at reducing greenhouse emissions by means of the replacement of the hydrochlorofluorocarbons gases with other less pollutant gases. The refrigeration systems are designed to be used with a specific refrigeration gas, and the noise emitted by these systems is certificated using this refrigeration gas. However, the regularizations have changed, and new refrigerant gases should be used. Considering that these new refrigeration gases work at different pressures, it is possible that the noise could be different with these gases. Moreover, the study of sound quality is very important for the manufacture as the perception and therefore the annoyance could change with the use of new gases. (2) Methods: Two different gases, R-449A and R-134A, have been studied. An acoustic camera has been used to measure and identify the sound quality in the refrigeration systems. (3) Results: The results have shown R-134A has better sound quality than R-449A. (4) Conclusions: This study shows that R-449A and R-134A could be a substitute for R-404A in terms of noise level

Monitoring sound and Its perception during the lockdown and de-escalation of COVID-19 Pandemic: A Spanish study

The lockdown measures in Spain due to the SARS-CoV-2 or COVID-19 (Coronavirus disease 2019) pandemic from 13 March to 21 June 2020 had extensive social and environmental implications. This study aims to understand how the measures of lockdown have influenced noise levels, as well as people’s perception of sound quality before and after lockdown, including de-escalation. For this purpose, an online survey was carried out. Moreover, the noise linked to the Global Positioning System (GPS) position of each individual respondent was recorded aiming to correlate the noise level with the result of the survey. An average reduction of over 30 dB was observed compared with the sound pressure level before lockdown. Furthermore, it was found that the loudness parameter, together with the overall level, increased as the country started relaxing restrictions. Additionally, results showed that the perception of noise quality changed depending on the phase of de-escalation (p p p p p p p < 0.05). It may be concluded that the most important measure to decrease noise levels is the reduction of traffic noise, through using eco-friendly public transportation or bicycles and limiting nightlife hours.We would like to acknowledge the support of the "Aula of software libre" at the University of Cordoba; "Aucorsa S.A." and "Interlight S.L."

Environmental conditions of dance rooms and its impact on dance conservatories teachers’ health (an Andalusian study)

Dance teachers have to be in long hours dancing. That entails repetitive movements, loud live music, and as well as forcing their voices. These demands can implicate severe health problems and other kind of illness as discomfort, stress, etc. However, the Spanish Ministry of Health only recognize as professional disease for this line of work, the vocal nodules. For this reason, this research studies the health problems in dance teachers in Andalusia, correlating the results of a survey carried out in different conservatories from Andalusia with measurement of noise emissions levels, assessment of noise exposure, and assessment of thermal environment in the classes measuring the thermal environment variables. To the authors’ knowledge, this is the first study where the influence of several sounds, such as tapping, castanets, and live music, on the health of dance teachers, musicians, and singers during flamenco classes has been researched. Results showed a correlation between some diseases, such as stress and the high level of sound in the classes. The sound levels were well above those established by European regulations reaching values higher than 85 dB(A) as equivalent continuous sound levels during the class time. This European regulation is stablished for an 8 h/day period, five days per week. The thermal environments are no adequate for this activity, mainly for high temperatures in Cordoba during summer. To improve the current working conditions, some recommendations were given to reduce the number of class hours and establish rest shifts, provide more information on health risks, or renovate the floor of some classrooms

Bibliometric Study of Technology and Occupational Health in Healthcare Sector: A Worldwide Trend to the Future

Since the eighties, technological tools have modified how people interact in their environment. At the same time, occupational safety and health measures have been widely applied. The European Agency for Safety and Health at Work considers that information and communication technologies are the main methods to achieve the goals proposed to improve working life and the dissemination of good practices. The principal objective was to determine the trends of publications focused on these technologies and occupational safety in the healthcare sector during the last 30 years. A bibliometric study was carried out. The 1021 documents showed an increased trend per country, especially for the United States (p < 0.001) and year (p < 0.001). The citations per year showed significant differences between citations of articles published before 2007 (p < 0.001). The year was also linked to the increase or decrease of articles (72.2%) and reviews (14.9%) (p < 0.001). The analysis of journal co-citations also showed that the main journals (such as Infection Control and Hospital Epidemiology) were linked to other important journals and had a major part in the clusters formed. All these findings were discussed in the manuscript and conclusions were drawn

Tuberculosis and Other Airborne Microbes in Occupational Health and Safety

Airborne pathogens and non-malignant infectious diseases such as tuberculosis are highly contagious and can have severe effects on healthcare workers. The symptoms of these diseases take time to manifest, which can prevent workers from noticing that they have been exposed until symptoms appear. The current paper sought to assess the occupational safety and preventative measures taken in laboratories in Spain, and to compare these measures with those reported by other studies worldwide. A cross-sectional study of workers (35–50 years old) was conducted using a web survey (N = 30), and a bibliometric analysis was carried out in the Scopus database (92 documents were selected). The occupational safety and health measures were inadequate, according to the opinions of the workers. The training (p < 0.01), the amount of work (p < 0.05), and how the workers followed their protocols (p < 0.001) were linked to incidents and exposure to airborne pathogens. The most significant previous publication was a report (848 citations) stating that the previous variables linked to exposure are vital for prevention. Most works focused on countries like the U.S.A. (p = 0.009) were reviews, with a limited number of studies focused on occupational safety

Social Media, Thin-Ideal, Body Dissatisfaction and Disordered Eating Attitudes: An Exploratory Analysis

Disordered eating attitudes are rapidly increasing, especially among young women in their twenties. These disordered behaviours result from the interaction of several factors, including beauty ideals. A significant factor is social media, by which the unrealistic beauty ideals are popularized and may lead to these behaviours. The objectives of this study were, first, to determine the relationship between disordered eating behaviours among female university students and sociocultural factors, such as the use of social network sites, beauty ideals, body satisfaction, body image and the body image desired to achieve and, second, to determine whether there is a sensitive relationship between disordered eating attitudes, addiction to social networks, and testosterone levels as a biological factor. The data (N = 168) was obtained using validated surveys (EAT-26, BSQ, CIPE-a, SNSA) and indirect measures of prenatal testosterone. The data was analysed using chi-square, Student’s t-test, correlation tests and logistic regression tests. The results showed that disordered eating attitudes were linked to self-esteem (p < 0.001), body image (p < 0.001), body desired to achieve (p < 0.001), the use of social media (p < 0.001) and prenatal testosterone (p < 0.01). The findings presented in this study suggest a relationship between body image, body concerns, body dissatisfaction, and disordered eating attitudes among college women

Occupational Safety and Health Training for Undergraduates Nursing Students: A Spanish Pilot

Most of blood borne and airborne pathogens are highly contagious, harmful and have prevalence among healthcare workers. In this group, healthcare students, especially nursing undergraduates, have even higher risk to be exposed and suffered a contagious accident. One of the main pillars to prevent exposure to such pathogens and decrease accidents seems to be through education. A prospective observational educational research focused on quantifying the students’ knowledge, and prevention culture was carried out. The educational approach based on the development of a technological tool, its integration in the students’ education, and posterior assessment. The Chi-square, ANOVA, Kruskal–Wallis, Man–Whitney U, and Spearman correlations were used to determine the effect of such educational methodology. The results, previous to the integration of the educational approach, showed differences between the elementary and proficient knowledge and correct procedure in each academic year (p < 0.05), being the best year the third academic year. The mean of elementary knowledge among second year students after the inclusion of the educational methodology improved for 2017/2018 with a mean of 7.5 (1.11) and in 2018/2019 with 7.87 (1.34). This study argued that the educational approach proposed could improve the prevention culture and knowledge among students and future healthcare professionals

Is possible to train health professionals in prevention of high-risk pathogens like the Ebola by using the mobile phone?

Health professionals are a concerning risk population because of the high prevalence of exposure to biological, especially during training that involves procedures implying direct contact with bodily fluids. Notwithstanding, the considerable advance of information and communication technologies (ICTs) during the last decades has provided with the divergence of new paths of research applied to training in the health field, allowing it integration in the field of biological risk prevention. The objectives of this study are: firstly, to estimate the level of knowledge about risk situations and the immediate response capacity of future professionals, prepare health professionals before different scenarios that can be presented in health care, and contribute to the appropriate decision making in possible scenarios. Secondly, to design and develop a mobile web application that, in a fast and ever-present manner, allows the healthcare professional, to have a quick response system that is clear and concise; and to evaluate by health students’ and professionals’ opinions the effectiveness of the technology developed. This study has been structured in two phases: first, to determine the degree of knowledge and compliance of biosecurity measures; and second, to perform a dual evaluation of the application. The survey of graduating students concerning practices has shown that the knowledge of risk prevention is adequate; meanwhile, a dynamic and efficient platform has been obtained, and its double assessment is satisfactory. It has been shown that the incidence of biological accidents is in the mean of the results of previous studies. An upgradeable web platform, ubiquitous and capable of being used in any electronic device available in the market, was obtaine