ÖZET: Bu araştırmada, SAE 4140 çeliğin tornalanması esnasında ses seviyesini ve yüzey pürüzlülüğünü etkileyen parametrelerin optimizasyonu amaçlanmıştır. Kesme parametreleri (ilerleme miktarı, devir sayısı ve talaş derinliği) üçer seviyede incelenmiştir. Deneyler Yanıt Yüzey Yöntemine göre elde edilen deney planına uygun olarak yürütülmüştür. Minitab 18 programıyla yapılan analiz sonuçlarına göre ses seviyesi için en etkili parametreler sırasıyla devir sayısı, ilerleme miktarı ve talaş derinliği olarak elde edilmiştir. Yüzey pürüzlülüğü için en etkili parametreler ise ilerleme miktarı ve devir sayısı olarak elde edilmiştir. Hem ses seviyesi hem de yüzey pürüzlülüğü için optimum çalışma seviyeleri belirlenmiştir. Bu değerler ilerleme miktarı için 0.1 m s -1 , devir sayısı için 750 dev dak -1 ve talaş derinliği için 0.5 mm olarak önerilmiştir.

In the cutting process with machine tools in the Machinery Manufacturing Industry; while the desired surface integrity is ensured by the optimization of the cutting parameters, the noise level must be kept at a minimum to protect the health of the workers. The noise level can be reduced by using this optimization without compromising the surface roughness through processing of EN AW 6013 material on a CNC milling machine. Experimental design was examined in three variables, three levels and two target functions. The effects of these parameters on the target function were studied by performing experimental plans determined by "Central Composite Design (CCT)" of Response Surface Method (RSM)". To assess the sound level and surface roughness, mathematical models were developed by performing regression analysis on the experimental results. These developed models have been tested with control experiments and it has been seen that the models have acceptable error rates. The obtained regression equation is highly modeled with a validity of 93.29% for sound level and 97.33% for surface roughness. Therefore, cutting parameters were found to be related to sound level and surface roughness values.

The aim of this study was to determine the sociodemographic characteristics that affect job stress and job satisfaction in 454 healthcare workers (physicians, nurses, midwives, technicians, and other healthcare personnel) working with COVID-19 patients in primary healthcare institutions in Turkey with a cross-sectional, web-based survey between 9 and 30 August 2021. The survey included a personal information form, a standard job stress scale, and the Minnesota Satisfaction Questionnaire. The levels of job stress and job satisfaction did not differ between male and female respondents. Singles reported lower job stress and higher job satisfaction than the married respondents. Job stress did not differ between departments, but respondents on the front line who worked in a COVID-19 intensive care unit (ICU) (at any point and/or at the time of the study) or the emergency department reported lower job satisfaction than those working in other departments. Similarly, while stress did not differ by educational status, satisfaction of respondents with bachelor’s or master’s degree was lower than that of the rest. Our findings also suggest that working in a COVID-19 ICU and age are significant predictors of higher stress, whereas lower education, working in a COVID-19 ICU, and being married are good predictors of lower satisfaction. Further research should include other sociodemographic variables that may affect stress and satisfaction at work, and similar studies should follow up to see what was left in the wake of the pandemic.

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