Exhaust Components Research Articles

Performance of Thermal Barrier Coating on Exhaust System Component

Thermal management in automobiles is important to keep the passenger cabin and heat sensitive components away from thermal effects. Hence various types of insulation methods are used to reduce the thermal effects. Heatshields are the most common method of thermal insulation. They can be classified into various types based on their construction architecture and insulation materials. Some of the heat shielding systems contain fibre materials that are hazardous to health due to their carcinogenic effects and hence not recommended. With increasing space constraints in the compact vehicle architecture designs, packaging space is premium, limiting the size of heatshields. In addition, from durability aspect, heatshields alone are not adequate to withstand high temperatures during the service life of exhaust systems. Hence the role of Thermal Barrier Coating (TBC) as an alternative solution comes effective. TBC’s are ceramic coatings which can take care of extended heat loads and temperature differences. This coating not only provides thermal insulation but also improves the fatigue life of substrate material. Hence in this paper, the application of TBC on exhaust system components with respect to thermal insulation and thermo mechanical fatigue are studied. Virtual analysis and physical test are carried out to validate the results. TBC coating on exhaust component shows promising results.

Method of verifying the emission level of the exhaust components of a special vehicle in relation to EURO III standard in road conditions

The following article presents the method of verification of EURO III standard in real life conditions for special vehicles. The test object qualified as a special vehicle of N3G category was tested in road conditions along a defined route, and then the obtained measurement results were compared to the exhaust emission standard (EURO III) applicable for this vehicle in transient testing mode. A method of comparing the emission factors in road conditions with the indicators obtained on the engine dynamometer was proposed. An AVL mobile exhaust gas analyzers (PEMS) dedicated for the Real Driving Emissions (RDE) road tests were used in the research.

Light-off Investigation of Oxymethylene Ether (OME) Considering the Presence of the Exhaust Components Heptane, Carbon, and Nitrogen Monoxide

Synthetic fuels and fuel blends like OMEs can contribute to tank-to-wheel CO2 emission savings. At the same time, it is known that these fuels have a lower exhaust temperature compared to conventional diesel. This effect has major impact on the exhaust after-treatment system, particularly in cold start conditions. This paper investigates the light-off behavior of exhaust gases containing OMEs by temperature-programmed oxidation experiments using a state-of-the-art oxidation catalyst. The main side product of catalytic oxidation of OMEs between 100 °C and the oxidation temperature T50, which was around 160 °C, was shown to be formaldehyde. While alkane oxidation, in this case heptane, was little influenced by OME oxidation, the oxidation temperature T50 of CO increases by more than 10 °C by OME addition. Nitrogen monoxide impeded the oxidation of OME in a similar way to the other components investigated. Due to the amount of FA produced and its toxicity, it could be concluded that it is necessary to heat up exhaust after-treatment systems of OME diesel engines even faster than conventional diesel exhaust after-treatment systems. The relatively high reactivity of OME on oxidation catalyst can be used by active thermal management approaches.

A review of technical solutions for RCCI engines

Nowadays, internal combustion engines are being developed in the directions that allow to maximize the efficiency of their work, in order to make the most economical use of fuels. The low-temperature method of burning fuels in HCCI engines - Homogenous Charge Compression Ignition - allows to improve the efficiency of the engine, thanks to the reduction of energy lost during cobustion process. For the further development of engines with this type of mixture auto-ignition, with increasing the range of fuels used for that king of engines, it is necessary to develop the RCCI engines. Reactivity-Controlled Compression Ignition - RCCI - is the way to control the air-fuel mixture auto-ignition by using the injection of second fuel injected into the combustion chamber before the combustion begins. The development of modern compression ignition engines is strongly dependent on engines with this type of ignition. Using two fuels with different physicochemical properties makes it possible to control the time of compression ignition and allows to use engine in full range of operation. RCCI is a special type of HCCI engine that allows to use many types of fuels with high combustion efficiency and low emission of harmful exhaust components. The paper analyzes the issues related to the adoption and development of engines with this method of ignition.

Global Pattern of CD8+ T-Cell Infiltration and Exhaustion in Colorectal Cancer Predicts Cancer Immunotherapy Response

Background: The MSI/MSS status does not fully explain cancer immunotherapy response in colorectal cancer. Thus, we developed a colorectal cancer-specific method that predicts cancer immunotherapy response.Methods: We used gene expression data of 454 samples (MSI = 131, MSI-L = 23, MSS = 284, and Unknown = 16) and developed a TMEPRE method that models signatures of CD8+ T-cell infiltration and CD8+ T-cell exhaustion states in the tumor microenvironment of colorectal cancer. TMEPRE model was validated on three RNAseq datasets of melanoma patients who received pembrolizumab or nivolumab and one RNAseq dataset of purified CD8+ T cells in different exhaustion states.Results: TMEPRE showed predictive power in three datasets of anti-PD1-treated patients (p = 0.056, 0.115, 0.003). CD8+ T-cell exhaustion component of TMEPRE model correlates with anti-PD1 responding progenitor exhausted CD8+ T cells in both tumor and viral infection (p = 0.048, 0.001). The global pattern of TMEPRE on 454 colorectal cancer samples indicated that 10.6% of MSS patients and 67.2% of MSI patients show biological characteristics that can potentially benefit from anti-PD1 treatment. Within MSI nonresponders, approximately 50% showed insufficient tumor-infiltrating CD8+ T cells and 50% showed terminal exhaustion of CD8+ T cells. These terminally exhausted CD8+ T cells coexisted with signatures of myeloid-derived suppressor cells in colorectal cancer.Conclusion: TMEPRE is a colorectal cancer-specific method. It captures characteristics of CD8+ T-cell infiltration and CD8+ T-cell exhaustion state and predicts cancer immunotherapy response. A subset of MSS patients could potentially benefit from anti-PD1 treatment. Anti-PD1 resistance MSI patients with insufficient infiltration of CD8+ T cells or terminal exhaustion of CD8+ T cells need different treatment strategies.

Research on Exhaust Emissions in Dynamic Operating States of a Combustion Engine in a Real Driving Emissions Test

The paper describes the method of investigations of exhaust emissions from a combustion engine under operation classified in terms of its dynamic states. In this paper, the engine operating states are determined through the vehicle driving under actual traffic conditions in the RDE (Real Driving Emissions) test. Based on the recorded tracings of the vehicle velocity, the engine states were classified as static for the acceleration of the absolute value lower than the adopted classification limit. Besides, the authors analyzed the engine operating states for the positive as well as negative acceleration. For the adopted engine operating states, zero-dimensional characteristics of the emission intensity for individual exhaust components were determined (average value, coefficient of variation). The influence of the analyzed operating states on the emission of individual exhaust components was assessed. The greatest increase in the intensity of the emission of nitrogen oxides was observed for the positive vehicle acceleration model and the lowest (also for the nitrogen oxides) for the negative vehicle acceleration. On average, the greatest increase in the emission intensity of pollutants and the intensity of particle number occurred for the dynamic states of the engine corresponding to positive acceleration. The conclusions from the performed investigations entitle the authors to propose a greater allowance for the exhaust emission-related criteria in the engine control algorithms.

Predicting of job burnout of female nurses based on effort – reward imbalance and characteristics of positive psychology

Introduction: The present study aimed to predict job burnout based on effort-reward imbalance and characteristics of positive psychology among female nurses of Shahid Rahnemoon Hospital of Yazd. Materials and Methods: The research method was descriptive; correlation type. 132 female nurses working in the different parts of Shahid Rahnemoon Hospital in Yazd were selected by random sampling. Three questionnaires (Muslesh & Jackson`s job burnout, Seligman`s positive psychological characteristics scale, and effort-reward imbalance of Seigersit) were completed by nurses. Results: The findings of the one-sample t-test showed that the job burnout level of nurses in the components of emotional exhaustion and depersonalization was moderate, but personal accomplishment is severe and statistically significant. Also, the score of effort-reward imbalance in female nurses is 1.09, which is higher than the cutting point and showed the imbalance of effort-reward in nurses. The situation of the meaning life component and the engagement life component (in the characteristics of positive psychology) among nurses was higher than the average and statistically significant, but the situation of the pleasant life was lower than the average and insignificant. The findings also showed that a positive and significant correlation between effort-reward imbalance with job burnout(r=0.458, p<0.01), as well as a negative and significant correlation between the positive psychological characteristics with job burnout (r=-0.65, p<0.01). In addition, the results of multiple regression analysis showed that 40% of variances of job burnout were predicted by the meaning of life, the effort-reward imbalance, and the engagement life. Conclusion: According to the results of this study, job burnout of nurses is moderate. Serious action should be taken by health policymakers and managers to increase the effort-reward balance improve the characteristics of positive psychology and reduce the burnout of nurses.

Association between serum lactate dehydrogenase and frailty among individuals with metabolic syndrome.

While metabolic syndrome (MetS) is associated with frailty, the correlation of serum lactate dehydrogenase (sLDH) and frailty with MetS remain uncertain. To investigate the relationship between sLDH and frail components in the US with MetS. A total of 4,066 participants aged 40–90 years were assessed from the database of the third National Health and Nutrition Examination Survey, 1988–1994. The participants were classified into MetS and non-MetS groups. Multivariate logistic regression analysis with four models were performed to assess the odds ratio (OR) of the divided tertiles of sLDH levels with frailty, and frail components including slow walking (SW), weakness, exhaustion, low physical activity (LPA), and low body weight (LBW). Higher sLDH levels were positively associated with frailty in the MetS group (p = 0.024) but not in non-MetS group (p = 0.102). After covariate adjustments, the OR of frailty in the upper two tertiles compared to the lowest tertile and revealed statistical significance (p < 0.05). Frail components of SW, weakness, exhaustion, and LPA were associated with higher sLDH (p < 0.05) except for LBW in MetS and non-MetS groups. The results demonstrated the strong association of higher sLDH levels and frailty among US individuals with MetS.

Burnout and Turnover Intention Among Peer Providers and Other Providers of Mental Health Services in a Rural Two-County Area.

Peer providers in the mental health field, having their own lived experience with mental illness, use their personal experience to assist the consumers of their services. Given high burnout rates in the mental health field, there have been two prior investigations of burnout among peer providers. The present study extends those prior investigations to a sample of peer providers working in community mental health programs in a rural area of the United States. Consistent with the prior studies, there were no differences in burnout between peer providers and other providers employed by those programs, with particularly strong support for the null hypothesis regarding the emotional exhaustion component of burnout. There were also no differences in strength of turnover intentions. However, among the non-consumer providers emotional exhaustion was correlated with both types of turnover intention assessed in this study (intent to change job setting within the mental health field and intent to leave the mental health workforce), whereas among the peer providers emotional exhaustion was correlated only with intent to leave the mental health field. Workload dissatisfaction was the workplace variable most strongly associated with emotional exhaustion among both types of providers. Other moderately strong inverse predictors of emotional exhaustion among peer providers were workplace community and workplace control, and the correlation between emotional exhaustion and workplace control was significantly stronger among the peer providers than among the other providers.

Investigating burnout levels and its determinants among the veterinary medicine students: The case of Istanbul University

This study was conducted to examine the burnout levels and its determinants among the veterinary medicine students. Answers (n = 447) to a survey formed the data of this study. Maslach Burnout Inventory - Student Scale, which was adapted to the Turkish language, was used to determine the burnout levels of the students. As a result, burnout levels were obtained as 13.31, 7.82, and 7.69 for Emotional Exhaustion (EE), Depersonalization (DP), and Personal Accomplishment (PA) components, respectively. Year of study and having a hobby had an effect on three of the burnout components. In order to determine the relationship between students’ burnout levels and students’ tendency to drop out, to work in a different profession after graduation and academic failure, a logistic regression analysis was conducted. Results revealed that year of study, WGPA, EE, DP, PA, repeating academic semester(s), number of repeated academic semester(s), and perceived difficulty of veterinary education were significantly associated with the students’ intention to drop out of the faculty. Gender, living situation, monthly income, EE, DP and PA affected education-occupation mismatch. Furthermore, gender, year of study, WGPA, living situation, monthly income, EE, DP, PA, and perceived difficulty level of the veterinary education had an influence on repeating academic semester(s). The results of this study reveal that burnout syndrome would lead to students’ dropping out of the faculty, education-occupation mismatch and academic failure. Future studies must be conducted throughout the country to assess burnout syndrome in veterinary students.

Microstructural and mechanical characterization of stainless steel 420 and Inconel 718 multi-material structures fabricated using laser directed energy deposition

Varying material properties are required for components designed to withstand harsh environments with simultaneous thermal and mechanical loading. This has been traditionally achieved by using multiple materials fabricated by traditional processes, followed by permanent or non-permanent joining techniques to realize a full, multi-material and multi-functional component. A potential simpler approach to this is to develop multi-material structures fabricated using additive manufacturing (AM). Additionally, many existing structures in can also be simplified by incorporating multi-material and multi-functional structures. Laser directed energy deposition (laser-DED) AM technique is suitable for fabricating multi-material structures using powdered feedstock material with high material flexibility. However, the fabrication of multi-material structures requires careful investigation into the compatibility and behavior of the constituent material systems. This remains a crucial task for multi-material deposition because there is relatively less knowledge available currently on the optimal multi-material mixtures for achieving adequate structural integrity and mechanical performance. In this study, multi-material structures of stainless steel 420 (SS420) and Inconel 718 (IN718) alloys were studied. These alloys were chose due to their applications in gas turbine components such as shaft assemblies, exhaust components and in the energy industry for fabricating various high strength, corrosion resistant devices. The specific compositions of the multi-materials structures investigated were: 100% SS420, 100% IN718, 75% SS420 + 25% IN718, 50% SS420 + 50% IN718 and 75% IN718 + 25% SS420. These samples were characterized for their microstructural, phase, and mechanical properties in the as-fabricated condition and compared with conventionally fabricated alloys. Significant differences in the microstructure and properties were observed between the laser-DED fabricated 100% alloys and mixtures of the two alloys. The laser-DED fabricated SS420 and IN718 alloys showed rapidly solidified microstructures typical to laser processes and properties comparable or better than the conventionally fabricated alloys. The three mixtures of SS420 and IN718 alloys showed microstructure and phases that were intermediate between the two unmixed alloys, as well as a higher amount of metallic carbide and Laves phases. Hardness and tensile tests indicated that the three mixtures of SS420 and IN718 were weaker than the unmixed laser-DED fabricated alloys due to the brittle carbide and Laves phases. Amongst the mixture, the mixture composition of 25%SS420 + 75%IN718 has showed highest strength and ductility.

Quality of sleep and burnout among undergraduate medical students at the university of Nairobi, Kenya

AimsThe main objective was to determine whether quality of sleep is associated with burnout among undergraduate medical students at the University of Nairobi.The null hypothesis in our study population was; 'There is no significant association between poor sleep quality and burnout'.BackgroundIn a pressure prevailing environment, medical students find themselves in a vicious cycle of cutting down on sleep in attempts to cope and adjust to increasing workloads. Students with poor sleep quality have been found to perform worse in their board exam and have strained social engagements. Ultimately, this chronic sleep deprivation may lead to burnout which may cause diminished sense of accomplishment and impaired professional conduct, that may be carried on to the career as a physician. High levels of burnout have been associated with suicides.MethodThe sample size obtained was 384 and participants were selected by a mixed sampling method. Data collection was through self-administered questionnaires. Scales used for this study were the Pittsburg Sleep Quality Index(PSQI) and the Oldenburg Burnout Inventory(OLBI).Ethical considerations were adhered to and approval obtained from the Kenyatta National Hospital-University of Nairobi(KNH-UON) Ethics Board. Data entry and analysis was by SPSS v23. Data from 336 questionnaires were deemed fit for analysis.ResultWith a response rate of 87.5%, the prevalence of poor sleep quality and burnout were 69.9% and 74.7% respectively. There was a significant positive association between poor sleep quality and female gender, clinical years of study, living with family, poorly perceived socio-economic state and poor subjective academic performance. In addition, being female, younger, pre-clinical years, living independently off-campus and poor subjective academic performance were significantly associated with higher levels of burnout.Burnout had a significant correlation with poor sleep quality. Daytime functioning, a component of sleep quality had the highest correlation with components of burnout, disengagement and exhaustion. Overall, 57% of the respondents had both poor sleep quality &amp;burnout, while only 12% were good sleepers with no burnout. Furthermore, having poor sleep increased the risk of having burnout by 2.8times. It is crucial that students adopt better sleeping habits to reduce the risk of burnout.ConclusionWith the high prevalence of poor sleep quality and burnout, peer-support groups and peer-led mentorship programs are recommended within this population to help deal with expectations, challenges and difficulties encountered within the course of medical education, in addition to preparing for the early future careers.

Estimating Emissions of Harmful Exhaust Components by Aircraft Engines During the Takeoff and Landing Cycle in Airport Space

Abstract This article examines, based on the available information and authors’ self-assessments, the environmental impact of turbine engine exhaust gases effect on the environment in the airport space during engines flight phases in the landing and takeoff cycle (LTO). The attention of aviation professionals is drawn to the fact that the amount of exhaust from the turbine engine is so significant that it may adversely change the ambient air at the airport. Consequently, increased emission level of carbon monoxide (CO), hydrocarbons (HC) during engine start-up and idle may pose a threat to the health of ramp staff. Also, high emission levels of nitrogen oxides (NOx) during takeoff, climb, cruise and descent is not without importance for the environment around the airport space. The paper gives CO2, HC, CO and NOx emission estimations based on ICAO Engine Emission Data Bank and the number of passenger operations at a medium-sized airport. It also provides calculation results of aircraft CO2, HC, CO and NOx emission using average times of aircraft maneuvers taken from aircraft Flight Data Recorder (FDR) in the LTO cycle various aircraft types at the airport. The latter, based on actual maneuvering times, lead to significantly reduced estimates of toxic exhaust gas emission volumes.

Effects on staff outcomes and process evaluation of the educating nursing staff effectively (TENSE) program for managing challenging behavior in nursing home residents with dementia: A cluster-randomized controlled trial

BackgroundChallenging behavior is prevalent in people with dementia residing in nursing homes and places a high burden on the nursing staff of dementia special care units. This study evaluates an educational program for nursing staff for managing challenging behavior: The Educating Nursing Staff Effectively (TENSE) program. This program can be tailored to care organizations’ wishes and needs and combines various learning styles. ObjectiveThe aim of this cluster-randomized controlled trial was to examine the short-term (3 months) and long-term (9 months) effects of the TENSE training program on experienced stress, work contentment, and stress reactions at work in nursing staff working in dementia special care units. DesignCluster-randomized controlled trial. MethodsNursing staff members of 18 dementia special care units within nine nursing homes from different Netherlands regions were randomized into an intervention (n = 168) or control (n = 129) group. The TENSE program consisted of a three-day training course and two follow-up sessions after three and six months, respectively. The primary outcome was stress experienced by nursing staff measured with the Utrecht Burnout Scale - C. Secondary outcomes were work contentment and stress reactions at work. Furthermore, process evaluation data on the reach of and compliance with the program and the program's feasibility and relevance were collected. Data were collected between November 2012 and November 2014. ResultsIn general, the participants appreciated the quality and relevance of the TENSE training and evaluated the content of the training as beneficial. The TENSE training had no effect on the components of experienced stress, i.e., emotional exhaustion (p = 0.751), depersonalization (p = 0.701), and personal accomplishment (p = 0.182). Furthermore, no statistically significant effects of the intervention on work contentment and stress reactions at work were found. ConclusionsThe TENSE training program did not have an effect on experienced stress, work contentment, nor stress reactions at work of nursing staff working in dementia special care units. In future studies, more focus on practicing new skills seems needed.Trial registration: NTR (Dutch Trial Registration) number NTR3620

Combustion Thermodynamics of Ethanol, n-Heptane, and n-Butanol in a Rapid Compression Machine with a Dual Direct Injection (DDI) Supply System

The development of internal combustion engines involves various new solutions, one of which is the use of dual-fuel systems. The diversity of technological solutions being developed determines the efficiency of such systems, as well as the possibility of reducing the emission of carbon dioxide and exhaust components into the atmosphere. An innovative double direct injection system was used as a method for forming a mixture in the combustion chamber. The tests were carried out with the use of gasoline, ethanol, n-heptane, and n-butanol during combustion in a model test engine—the rapid compression machine (RCM). The analyzed combustion process indicators included the cylinder pressure, pressure increase rate, heat release rate, and heat release value. Optical tests of the combustion process made it possible to analyze the flame development in the observed area of the combustion chamber. The conducted research and analyses resulted in the observation that it is possible to control the excess air ratio in the direct vicinity of the spark plug just before ignition. Such possibilities occur as a result of the properties of the injected fuels, which include different amounts of air required for their stoichiometric combustion. The studies of the combustion process have shown that the combustible mixtures consisting of gasoline with another fuel are characterized by greater combustion efficiency than the mixtures composed of only a single fuel type, and that the influence of the type of fuel used is significant for the combustion process and its indicator values.

Experiences of Burnout Among Nurse Anesthetists

Recent and mounting evidence indicates burnout among healthcare providers in the United States has been steadily rising over the last decade. Review of the literature has indicated that burnout affects provider clinical performance, professionalism, quality, incidence of medical errors, and intention to stay in the profession. Burnout has been shown to impact provider quality of life. However, education focused on coping skills can reduce burnout amongst providers. This article describes a quality improvement project conducted to determine the effect of a burnout awareness and coping skills program to decrease burnout among nurse anesthetists at a level one trauma center. The educational program provided information that helped staff to identify signs and symptoms of burnout and offered strategies to reduce burnout. We describe the project methods, and results, which suggested a significant decrease in participants’ levels of the emotional exhaustion component of burnout following participation in the program. We offer discussion about the clinical significance of our findings, note project limitations, and conclude with implications for research and practice.

Evaluation of stress, burnout and hair cortisol levels in health workers at a University Hospital during COVID-19 pandemic

In the critical context of COVID-19 pandemic, healthcare workers are on the front line, participating directly in the care, diagnosis, and treatment of patients with COVID-19. This exposes them to a higher risk of developing chronic stress, psychological distress, and any other mental health symptoms. Objectiveto evaluate stress and burnout in a health workers population and, in addition, to measure hair cortisol concentration as a current biomarker of stress. Materials and methods234 health workers from Hospital de Clínicas “José de San Martín”, Buenos Aires University, were included in this study. In this population hair samples were obtained from the posterior vertex as close to the scalp as possible and the individuals completed the following surveys: perceived stress, social support, burnout scale, life event scale, and sociodemographic data. Hair cortisol was measured by an automated chemiluminescent method. The studied population was divided into three groups considering those individuals below the healthy reference sample range (< 40 pg/mg hair), within the healthy reference range (40–128 pg/mg hair) and above the reference range (> 128 pg/mg hair). This study used a transversal and observational design. ResultsOur results show that 40% of the studied population presented hair cortisol values outside of the healthy reference range. In the whole studied population, a direct correlation was found between hair cortisol concentration and perceived stress as well as between hair cortisol concentration and the emotional exhaustion component of burnout (r = 0.142, p = 0.030; r = 0.143, p = 0.029, respectively). 12% of the studied population showed Burnout (52% doctors and residents, 19% nurses, 19% administrative personnel). Higher values in hair cortisol levels were found in the group with burnout versus individuals without burnout (p = 0.034). Finally, a mediation analysis was performed, finding that depersonalization is a mediating variable in the relationship between self-perceived stress and hair cortisol level (F = 4.86, p = 0.0086; indirect effect IC: 0.0987-1.8840). ConclusionThis is the first study in which a stress biomarker such as hair cortisol is evaluated in this population and in this context. Healthcare workers are subjected to increased levels of stress and burnout. High depersonalization, emotional exhaustion, and decreased personal sense of accomplishment characterize this population. It is the responsibility of the health authorities to implement strategies to manage this psychological emergency.

The influence of the heating time of a catalyst-covered glow plug on the exhaust emissions from a diesel engine

The paper discusses the application of an in-cylinder catalyst allowing a reduction of the exhaust emissions from a diesel engine. Its placement in the combustion chamber, the area where the process of combustion takes place, allows reducing the emissions (carbon monoxide, hydrocarbons, particulate matter) ‘at source’. The paper presents the possibilities of boosting the efficiency of catalysts in diesel engines by extending the time of heating of a glow plug (the catalyst applied on the glow plug). The tests were performed for the following conditions: no heating (marked 0+0), glow plug heating for 60 s after engine start (marked 0+60), glow plug heating prior to engine start for 60 s and glow plug heating for 60 s after engine cold start (marked 60+60). An improvement in the efficiency of oxidation of the exhaust components was observed as the glow plug heating time increased.

Examining the role of transformational leadership and mission valence on burnout among hospital staff

PurposeThe present study contributes to our understanding of how to curb burnout among hospital staff over time. The authors extend existing research by examining the mediating role of mission valence in the link between transformational leadership and burnout.Design/methodology/approachSelf-administered questionnaire data from employees in a Canadian general hospital (N = 185) were analyzed using a time-lagged research design to examine whether transformational leaders can increase employees' attraction to the organization's mission (i.e. mission valence) and in turn alleviate long-term burnout.FindingsStructural equation modeling analysis demonstrated that transformational leadership (time 1) was negatively related to the burnout components of emotional exhaustion and depersonalization (time 2). Further, the results showed that mission valence mediated these relationships.Practical implicationsThe study findings are important for managers and professionals as they identify transformational leadership as a potent strategy to alleviate employee burnout and clarify the process through which this is achieved, namely, by increasing mission valence.Originality/valueTo date, surprisingly little research has explored how transformational leadership influences followers' burnout. To address this issue, the present study examined the role of transformational leadership on staff burnout through the mechanism of increasing mission valence. Understanding how to mitigate burnout is particularly critical in health care organizations given that burnout not only negatively impacts employee wellbeing but also the wellbeing and quality of care provided to patients.

Evaluation of changes in fuel delivery rate by electromagnetic injectors in a common rail system during simulated operation

The objective of this study was to determine changes in fuel delivery rate by common rail system injectors during their simulated operation on a test stand. Four Bosch injectors used, among others, in Fiat 1.3 Multijet engines were tested. The injectors were operated on a test rig at room temperature for 500 hours (more than 72 million work cycles). During the test, pressure and injection frequency were changed. Changes in the operating parameters were estimated based on obtained injection characteristics and effective flow area determined thereby. The observed changes in fuel delivery rate were compared with results of the surface analysis of control valves and nozzle needles. Despite the stated lack of wear, significant changes in the dynamics of injector operation were observed, particularly at short injection times. Small pilot injections cannot be corrected by the fuel injection control system because they do not affect the changes in torque; however, they do affect the combustion process. This creates conditions for increased emission of toxic exhaust components.