Duration Of Work Research Articles

Assessment of Lung Function in Scavenger Workers at Some Waste Dumpsites in Baghdad City

Waste scavengers face occupational hazards from exposure to toxic landfill emissions, putting them at risk for respiratory illnesses. This study aimed to assess the impacts of landfill gases on lung function in scavengers. Spirometry was used to evaluate lung function in scavengers at 5 dumpsites in Baghdad compared to non-exposed controls. The results showed that winter measurements in the internal measuring point for carbon dioxide indicated that the highest concentration was 454.89 ppm in the Adhamiya landfill and the lowest concentration was 397.65 ppm in the Baghdad Aljadeeda landfill. Lung disease cases were recorded and correlated to landfill sites, work duration, and seasons. The results of the lung efficiency examination showed a clear decrease in spirometry parameters at high-pollution landfill sites with varying concentrations of particulates and gases compared to the control group—more airway restriction cases correlated with increased years of scavenger exposure and higher pollutant levels. As noted, severe respiratory symptoms increased in the summer season likely due to the influence of climatic factors.

Application of the Randomized Earned Value Method to assess the advancement of the construction of the office building under the unstable implementation conditions

The REVM method is a modernized option of classical EVM method. The new method has been developed for applying in unstable condition of works implementation. When the works can be accidentally disturbed and the impact of random disruption factors on course and results of works must be taken into consideration. Next, Randomized Budgeted Duration to Completion and Randomized Budgeted Cost to Completion that is duration and cost of works remaining to execution after each inspection, as well as the Randomized Budgeted Duration at Completion and Randomized Budgeted Cost at Completion that is duration and cost of all works of the project completion after the site inspection. Moreover, the risk of durations and costs overrun of works are evaluated. It is important that input data required for the REVM method are the similar and are measured in the same way as in typical control of advancement works. But results of the application consist new decision information. Control of the investment under deterministic conditions, without taking into account the risk of disruptions, resulted in a final deviation from the planned budget of over 7%, and from the planned completion of the investment by almost 12%. Without analysing the factor related to disruptions at the investment implementation stage, the material and financial schedule was completely outdated. On the other hand, when controlling the investment under risk conditions and introducing organizational and technological changes adequate to the inspection reports, the final deviation from the planned budget was less than 2%, and slightly more than 2% from the planned completion date. Researches confirm that the results received by using the REVM method well reflect real situation of works implementation.

Work Duration and Sleep Quality Among Young Workers (A Study In Coffee Shops In West Denpasar District)

This study aimed to describe the work duration and sleep quality among young workers, conducted in coffee shops in the West Denpasar area in 2023. This study employed a quantitative descriptive method with an observational study design and a cross-sectional approach. The sample consisted of 56 coffee shop workers in the West Denpasar area. The variables in this study included the age of workers, work duration, and sleep quality. Data collection was done using primary data through a questionnaire instrument, and data analysis involved descriptive statistical tests. The research results showed that the average age of workers was 20.39 years, with the youngest worker being 18 years old and the oldest 24 years old. The majority of workers had poor sleep quality (80.4%) and worked with a duration of ≥40 hours per week (83.9%). This study concludes that young workers mostly work for ≥40 hours per week and have poor sleep quality. These findings indicate that the conditions of young workers have high-risk factors that could potentially trigger workplace accidents.

Risk Factor Analysis of Musculoskeletal Disorders (MSDS) in Woman Shellfish Peeler (Geloina Erosa) in Pantai Cermin District

<div><table cellspacing="0" cellpadding="0" align="left"><tbody><tr><td align="left" valign="top"><p>Woman shellfish peelers <em>(Geloina Erosa) </em>are at risk of developing <em>musculoskeletal disease</em> (MSDS) because of their activities that involve lifting, moving heavy items, carrying weights on the head, bending, or looking up when carrying weights. The majority of women's jobs in Pantai Cermin sub-district are shellfish peelers <em>(Geloina Erosa). </em>This study aims to identify risk factors for <em>musculoskeletal disease</em> (MSDS) in female peelers of Kepah Mussels <em>(Geloina Erosa).</em> Using a cross-sectional study design and quantitative methodology, the population in this study was 45 and The sampling technique used a total sampling of 45 respondents. The data was then analyzed using a correlation test with the help of the SPSS program. The results showed that age, length of work, duration of work, weight, and work posture affect the risk of musculoskeletal disease (MSDs) in female shellfish peelers <em>(Geloina Erosa) </em>in Pantai Cermin District. But years of service are negatively affected This signifies that the longer a person works, the lower their likelihood of experiencing. One strategy to reduce the possibility of musculoskeletal disease complaints (MSDs) is to increase awareness of work posture, comply with occupational safety health regulations, stretch before starting work to reduce pain in parts of the body that experience musculoskeletal disorders, suggestions for improving sitting posture so that the legs are not bent and rest when the body experiences pain to reduce the risk of complaints. The goal is to prevent work fatigue and complaints of MSDs. Women who do kepah peeling work are also expected to routinely stretch, take adequate rest and to reduce soreness in the calves of female shellfish peelers (Geloina Erosa) in Pantai Cermin District It is recommended to use tables and chairs with parallel heights so as not to bend the legs too much and wrap when stripping shells (Geloina Erosa).</p><p><em><br /></em></p></td></tr></tbody></table></div><strong><em>Keywords: MSDS risk, Shellfish peeler (Geloina Erosa), Women, Work Posture</em></strong>

Prevalence of Work-Related Musculoskeletal Disorders among Laundry Workers in North Sulawesi Province, Indonesia

Introduction: Work-related musculoskeletal disorders (WMSDs) are a serious problem that can affect the health and productivity of laundry workers. Workers who experience such disorders may experience pain, muscle stiffness, joint inflammation, and even serious injury. This study aimed to investigate the prevalence of work-related musculoskeletal disorders among laundry workers in North Sulawesi. Methods: This study is a quantitative descriptive cross-sectional survey conducted in March 2023 – April 2023 in Minahasa District North Sulawesi Province, specifically Tondano-Tomohon City. A total sample of 225 laundry workers was taken using the convenient sampling technique. The questionnaire used to assess WMSDs was the Nordic Body Map. The chi-square test was applied to find the association between age and musculoskeletal disorders among laundry workers. Results: Complaints felt in all parts of the worker's body 5.38% were very painful, 17.81% were painful, 36.39% were rather painful, and 39.67% were not painful. The body part that experienced the most complaints of severe pain was back at 10.2%, feeling pain was the waist at 37.3%, feeling pain was the right arm at 47.1%, and no pain was the left elbow at 71.6%. Conclusion: The prevalence of work-related musculoskeletal disorders among the study population was significantly associated with age, sex, nutritional status, and work experience with musculoskeletal complaints (p<0.05). While there is no relationship between work duration and education level with musculoskeletal complaints (p>0.05). Therefore, appropriate interventions need to be made to improve working conditions, protect workers' health, and minimize the risk of work-related musculoskeletal disorders in the laundry industry.

Ocular surface changes during COVID-19 pandemic among university faculty members with dry eye disease in northern India: A longitudinal study

ObjectiveThe pandemic has brought a paradigm shift in pedagogical modalities throughout the world, with a resultant increase in screen time and ultra-violet light exposure among both students and teachers. The current study was conducted to analyze ocular surface changes in university faculty members with dry eye disease (DED) during the second wave of COVID-19 pandemic in India. MethodsA cross-sectional study was conducted among university faculty members of a medical university in India. An online questionnaire was sent via social media from December 2020 to January 2021, which consisted of questions on demographic details, DED symptoms and use of visual display terminals. All those participants who had DED based on Ocular Surface Disease Index (OSDI) score were followed-up after one month when the pandemic had subsided. ResultsOut of the 150 faculty members in the university, 130 completed the survey (response rate 86.7%). The number of participants with symptomatic DED based on OSDI score was 111 (85.3%). All these participants showed a statistically significant change in subjective measurement of DED symptoms after one month, using OSDI questionnaire. ConclusionDED symptoms increased during the pandemic and there was a statistically significant change in the OSDI scores suggestive of ocular surface damage and a positive relationship with increased digital screen time. The finding has implications as targeted interventions need to be undertaken to mitigate the effects of increased screentime, especially among populations with more duration of near work using digital screens.

Plateau in Core Temperature during Shorter but Not Longer Work/Rest Cycles in Heat.

This study compared physiological responses to two work/rest cycles of a 2:1 work-to-rest ratio in a hot environment. In a randomized crossover design, fourteen participants completed 120 min of walking and rest in the heat (36.3 ± 0.6 °C, 30.2 ± 4.0% relative humidity). Work/rest cycles were (1) 40 min work/20 min rest [40/20], or (2) 20 min work/10 min rest [20/10], both completing identical work. Core temperature (Tc), skin temperature (Tsk), heart rate (HR), nude body mass, and perception of work were collected. Comparisons were made between trials at equal durations of work using three-way mixed model ANOVA. Tc plateaued in [20/10] during the second hour of work (p = 0.93), while Tc increased in [40/20] (p < 0.01). There was no difference in maximum Tc ([40/20]: 38.08 ± 0.35 °C, [20/10]: 37.99 ± 0.27 °C, p = 0.22) or end-of-work Tsk ([40/20]: 36.1 ± 0.8 °C, [20/10]: 36.0 ± 0.7 °C, p = 0.45). End-of-work HR was greater in [40/20] (145 ± 25 b·min-1) compared to [20/10] (141 ± 27 b·min-1, p = 0.04). Shorter work/rest cycles caused a plateau in Tc while longer work/rest cycles resulted in a continued increase in Tc throughout the work, indicating that either work structure could be used during shorter work tasks, while work greater than 2 h in duration may benefit from shorter work/rest cycles to mitigate hyperthermia.

Electrophysiological and Cognitive Changes in Hard Coal Miners Associated with Working Underground.

Miners working underground face some risk factors that affect the nervous system-such as high noise, dark environment, chronic stress, and exposure to toxic gases. However, it is not known whether these risk factors affect the cognition of miners. In this study, the cognitive changes of miners were examined through event-related oscillations via electroencephalogram (EEG). Twenty underground miners and control groups, equal to each other in age, education level, and working duration, participated in this study. Neuropsychological tests were applied to all participants to examine their cognitive characteristics. Then, 20-channel EEG was recorded for electrophysiological changes during visual oddball paradigm. Event-related power spectrum and phase locking were analyzed in delta (0.5-3.5), theta (4-7), and alpha (8-13 Hz) frequency bands. It was determined that the delta responses that emerged during the target stimulus differed between the two groups in terms of phase locking (p < 0.05). Considering event-related alpha responses, a statistical difference was found regarding power spectrum and phase locking (p < 0.05). Moreover, the alpha power spectrum in the miners was found to be negatively statistically correlated with working duration (p < 0.05). This study determined that the event-related electrophysiological responses of the miners were negatively affected depending on the working conditions. In addition, neuropsychological assessment determined miners had deficiencies in learning and memory skills and many other cognitive functions such as attention, behavioral inhibition, and visual perception.

Improving the performance of heat sinks through the integration of fins and the utilization of graphene-mixed latent heat energy storage

Effective thermal management is significant to ensure the safety of all operating systems. However, these systems demand innovative thermal management technology. A heat sink with improved thermal conductivity is one of the passive heat management techniques. This study focuses on enhancing thermal management in devices by evaluating the performance of a heat sink with and without fins integrated with high thermal conductivity graphene-incorporated phase change material. Paraffin wax with a melting temperature of 58 °C was used as the phase change material. The study examines how the addition of graphene nanoparticles improves heat transfer capacity and extends the heat sink's working duration. The findings revealed that the phase change material extends the heat sink's working duration while adding nanoparticles improves performance. The performance of the phase change material and mixture of the nanoparticles was examined using a finned heat sink under constant heat input. The heating and cooling cycle of the heat sink was examined. The performance of the heat sink with fins and nano PCM was increased by 30 % compared to the baseline heat sink at 15 W heat input. This performance was increased to 45 % when the heat input changed to 30 W. The results indicated that nanoparticles in the phase change material augment the heat sink's recovery time, irrespective of the influence of fins.

Relationship between night work and health-related quality of life: an analysis based on profiles and cumulative duration of exposure to night work among French workers in the CONSTANCES cohort.

The aim of this study is to estimate the association between night work and health-related quality of life (HRQoL) among French workers. The association between cumulative duration of night work and HRQoL was also investigated. Three career-long night work exposure groups were defined at inclusion in the CONSTANCES cohort: permanent night workers, rotating night workers and former night workers. Day workers with no experience of night work were the reference group. HRQoL was assessed using the Short Form Health Survey (SF-12), in particular the physical component summary (PCS) and mental component summary (MCS) scores, with a higher score indicating better HRQoL. Several linear regression models were built to test the association between night work exposure and HRQoL. The relationship between cumulative duration of night work and HRQoL scores was analyzed using generalised additive models. The sample consisted of 10,372 participants. Former night workers had a significantly lower PCS score than day workers (β [95% CI]: -1.09 [-1.73; -0.45], p = 0.001), whereas permanent night workers had a significantly higher MCS score (β [95% CI]: 1.19 [0.009; 2.36], p = 0.048). A significant decrease in PCS score from 5 to 20years of cumulative night work was observed among former night workers. Former night workers had poorer physical HRQoL in contrast to permanent and rotating night workers who had similar or even better HRQoL than day workers, suggesting the well-known healthy worker survivor effect. Consequently, both current and former night workers require regular and specific follow-up focused on the physical components of their health.

Occupational and Return-To-Work Characteristics of Covid-19 Patients After Treated in Udayana University Hospital

Corona virus disease 2019 (COVID-19) is a new disease caused by severe acute respiratory syndrome corona virus 2 (SARS-COV-2). The COVID-19’s symptoms are fatigue, muscle pain, and psychological disorders. The purpose of this study was to describe the occupational characteristics and health conditions of COVID-19 patients who had recovered after being treated at Udayana University Hospital. This study is a descriptive study with a quantitative method and cross-sectional design. The research samples were 110 COVID-19 patients treated at Udayana University Hospital from June to August 2020 and taken using random sampling. The results showed that the highest proportion of respondents were aged between 24-44 years (44.5%), with almost equal proportions of women (50.1%) and men (49.09%). Most of them lived in Denpasar (46.36%). Most respondents work as private sector employees (24.55%), and 70% of them were using personal protective equipment (PPE) while working. Most respondents needed less than seven days to return to work after being declared “in recovery state” (60%), with the remaining 55.5% having a decreased work duration to be less than 8 hours per day. The proportion of respondents with comorbidities was 30.91%. As many as 27.27% were experiencing previously similar symptoms (fever, fatigue, cough) 4 to 5 months after being declared “cured.” COVID-19 patients who have recovered should be monitored for a longer period of time to evaluate the symptom reoccurrence and its impact on their occupational and health conditions.

RELATIONSHIP BETWEEN WORK DURATION, LENGTH OF WORK, AND SLEEP DURATION WITH WORK FATIGUE AMONG ONLINE TAXI BIKE DRIVERS IN GREATER JAKARTA

Background: Online taxi bike drivers were part of the road users vulnerable to accidents due to a demand that required online taxi bike drivers to work on the highway. Work duration, length of work, and sleep duration could cause the fatigue experienced by online taxi bike drivers. Purpose: See the strength of the relationship between work duration, length of work, sleep duration and work fatigue among online taxi bike drivers in Greater Jakarta. Method: This study was observational with a cross-sectional design involving as many as 52 online taxi bike drivers selected by non-probability sampling from online taxi bike drivers in Greater Jakarta from the end of November 2022 to early December 2022. Result: The majority of respondents (84.6%) were under 40 years old, male (92.3%), worked more than eight hours a day (55.8%), had experience as online taxi bike drivers for more than 3 years (73.1%), sleep duration less than 8 hours (78.8%), and there were 36 online taxi bike drivers (69.2%) reported experiencing high-very high levels of fatigue. The work duration is significantly related to work fatigue (p-value = 0.002). Also, there was no significant relationship between the length of work (p-value = 0.268) and sleep duration (p-value = 0.058) with work fatigue. Conclusion: There was a significant relationship between work duration and work fatigue, and there was no significant relationship between the length of work and sleep duration with work fatigue. The taxi drivers with work duration &gt;8 hours, length of work &gt;3 years, and sleep duration &lt;8 hours had higher risk factors for work fatigue. If a taxi bike driver works more than 8 hours daily, it is advisable to compensate with adequate rest.

Prior-Night Sleep Predicts Next-Day Sedentary Behavior as a Function of Work Duration in Public Safety Telecommunicators.

Public safety telecommunicators are at significant risk for obesity and other health conditions, which can likely be attributed to high-intensity job functions that occur in seated positions for long work hours. However, the interactions between these variables, as well as the role of recovery sleep, remains underexplored. We hypothesized that work duration would moderate the daily relationship between prior-night sleep and next day sedentary behavior. To test this hypothesis, actigraphic estimates of sleep and activity were gathered in 47 public safety telecommunicators over an average of 11 days (n = 525 cases). Results indicated that participants spent more time sedentary when they had less efficient, prior-night sleep in combination with both longer shifts or longer-than-usual same-day shifts. Wake time after sleep onset and total sleep time were positively associated with more next-day sedentary behavior, but only when working fewer hours. These findings suggest that public safety telecommunicators engage in compensatory, behavioral sleep patterns that are consistent with chronic insomnia and affected by both cumulative and daily work duration. Taken together, these results provide strong proof-of-concept that sleep health promotion and insomnia intervention might decrease sedentary behavior.

Determining the Leadership Order of the Clinically Responsible Nurse Working in a University Hospital

This study aims to determine the leadership orientations of clinical chief nurses. In the descriptive study, the G-Power 3.1.9.4 program was used to calculate the sample size and the number of people planned to be included in the study was calculated as 50 with 5% error and 95% power. In this direction, all (50) clinical nurses working in a university hospital between 10.05.2023 and 30.05.2023 will form the study sample group. The data of the study will be collected from individuals with a socio-demographic "Leadership Orientation Questionnaire" prepared by the researchers. 84.6% of the participants were female and 15.4% were male. While 89.7% of the participants are married, 10.3% are single. While 56.4% of them are graduates, 43.6% of them are undergraduates. 46.2% of the participants have been in management for 0-5 years, 28.2% for 10 years and above, and 25.6% for 5-10 years. While the participants' human-oriented leadership behavior score average was 7.79, the minimum score was 3 and the maximum score was 12. While the task-oriented behavior average score was 12.62, the minimum score was 4 and the maximum score was 19. While the leadership orientation total score average was 20.41, the minimum score was 7, and the maximum score was 27. As a result of this study, there is no significant difference between the sub-dimensions of the leadership orientation scale and age, gender, marital status, educational status, duration of work in the profession, and management process. Therefore, extra pieces of training should be planned for responsible nurses, taking into account clinical leadership. There are few studies on this subject in the literature. It is recommended to increase the studies.

Psychotherapy duration and work disability: A prospective Finnish register study.

The influence of psychotherapy duration on common mental disorder (CMD) outcomes remains a topic of ongoing debate. Whereas most research has focused on CMD symptom change, the evidence on the psychotherapy duration of subsequent CMD-related work disability and the change in psychotropic drug purchases is scarce. We used a register-based cohort representing 33% of the Finnish population. The participants included working-age individuals (N = 12,047, 76% women, mean age = 36) who initiated long-term psychotherapy, between 2014 and 2017. They were followed from 2011 to 2021 and psychotherapy duration ranged from less than a year to over 3 years. We used an interrupted time series design to analyze the psychotherapy duration-dependent changes in CMD-related work disability (primary outcome, operationalized as depression or anxiety-related sickness absence, SA, days) and the annual number of psychotropic drug purchases or distinct drugs purchased (secondary outcomes). There were no differences in the levels of work disability or drug purchases before the psychotherapy. We observed a decreasing level and trend in all outcomes across all psychotherapy duration groups. The largest decline in level was observed in the <1-year duration group (88% decline for SA and 43%-44% for drug purchases) while the smallest decline was in the 3+ years duration group (73% for SA and 27% for drug purchases). Work disability outcomes and duration varied among individuals, even with similar initial mental health-related work disability or use of auxiliary psychotropic treatments. Compared to longer psychotherapy, shorter psychotherapy was associated with sharper improvements.

Determining Kidney Damage Risk Factors Associated with Urine Paraquat Levels and Biochemical Urine Profile of Farmers in Banjarbaru, South Kalimantan, Indonesia

Abstract Aim: Kidney damage from paraquat is influenced by several factors, including the duration of work, the span of exposure from the pesticide spraying, and the nutritional status of the farmers. This damage can be indicated by the high levels of paraquat and changes of the biochemical status in the urine. The present study aimed to analyze the relationship between the length of work, duration of spraying, and the nutritional status obtained from the measurement of body mass index (BMI) values, with the paraquat levels and biochemical status of the farmer’s urine samples. Materials and Methods: This study was a cross-sectional study and was conducted in September 2022 in North Landasan Ulin Village, Banjarbaru City, South Kalimantan, Indonesia. The length of work and spraying duration were obtained from the direct interviews, while the BMI values were calculated by dividing the body weight (kg) by the body’s height (m). Analysis of the paraquat levels in the urine was measured using a spectrophotometer, while the urine’s biochemical status was obtained using the dipstick colorimetric method. Statistical analysis used: the relationship between each variable is analyzed using the Spearman rank correlation test. Results: Results from the study show that the length of work, duration of spraying, and BMI were moderately associated with an increase in the urinary paraquat levels (correlation coefficient [Rs] 0.26–0.50) (P &lt; 0.05); although the previous factors did not appear to correlate with any changes in the urine’s biochemical status. Conclusion: In summary, prolonged exposure to the spray in combination with the farmers’ long work hours, and also factoring in the abnormal BMI values, resulted in an increase of paraquat levels in the urine.

Epidemiological Characteristics of Inflammatory Demyelinating Diseases of the Central Nervous System Including Multiple Sclerosis

Relevance. Demyelinating diseases of the central nervous system and multiple sclerosis, in particular, make their debut at a young age and can lead to profound disability and death within a few years. In the last decade, there has been an increase in the number of cases of demyelinating diseases in Russia and in the world, which necessitates an in-depth study of these pathologies. Goal. To study the dynamics and features of the formation of morbidity, prevalence and mortality from demyelinating diseases of the central nervous system, including multiple sclerosis in various population groups in the Russian Federation. Materials and methods. The study design is a descriptive retrospective epidemiological study (continuous). The data was sampled from the forms of the federal state statistical observation on the distribution of the deceased by gender, age groups and causes of death of Rosstat (FSN S-51), as well as from the statistical collections of the Federal State Budgetary Institution "Central Research Institute of the Ministry of Health of the Russian Federation "Morbidity of the population" from 2009 to 2021. Results. The analysis of the data showed that in 2009-2021 in Russia there was an increase in idiopathic inflammatory demyelinating diseases (IDD) and multiple sclerosis (MS) among the adult population and adolescents aged 15 to 17 years. There is no tendency to increase or decrease the incidence among children under 14 years of age. The highest average long–term incidence rates of IDD and MS among adults are observed in the Ufa region (7.13 ± 0.27 and 5.31 ± 0.23 per 100 thousand adults, respectively), among children under 14 - IDD in the Central Federal District (1.88 ± 0.18 per 100 thousand contingent) and MS in the Central Federal District and Volga Federal District (0.22 ± 0.07 per 100 thousand contingent). Among children from 15 to 17 years of age, the highest incidence of IDD is noted in the Northwestern Federal District (4.41 ± 1.10 per 100 thousand contingent) and the Ural Federal District (4.40 ± 1.09 per 100 thousand contingent), RS – in the Central Federal District (2.67 ± 0.51 per 100 thousand contingent). IDD and MS are the least common among all age groups in the Far Eastern Federal District. Over the period from 2000 to 2020, there has been a decrease in MS mortality in the Russian Federation by 34%, from 0.72 to 0.48 per 100,000 population. The average annual mortality rate from MS among men was 0.4 ± 0.021 cases per 100 thousand of the contingent, among women 0.5 ± 0.023 cases per 100 thousand of the contingent. Conclusion. The increase in the incidence of demyelinating diseases and MS, in particular, is an important medical and social problem. These pathologies significantly reduce the quality of life and shorten the duration of work, due to the development of persistent disability in the young population. The study showed the uneven distribution of the disease across the territories of the Russian Federation, which in the future will improve the logistics of drug delivery and the provision of medical personnel, which confirms the relevance of constant and in-depth study of the epidemiology of idiopathic inflammatory demyelinating diseases in Russia.

МОДЕЛЬ ОЦЕНКИ ПОТЕРЬ ПРИ УБОРКЕ СОИ

Soybean losses during combine harvesting, depending on conditions, can reach more than 30%. This has a significant impact on the profitability of soybean production as a whole. The article is devoted to modeling possible losses when harvesting soybeans in an agricultural enterprise. The results of monitoring the quality of soybean harvesting and information materials published in periodicals were used in the research process. Total losses were considered as the sum of self-shedding losses due to harvesting delays and losses directly behind the combines. Three options for soybean harvesting are considered: within the agricultural period, partially within the agricultural period and completely beyond the agricultural period. Modeling of losses by self-shedding is performed depending on the harvesting option and the duration of work over the agricultural period. Modeling of soybean losses for a separate combine is carried out on the basis of dependencies that take into account changes in losses from the duration of work over the agricultural period, operating speed, cutting height and lodging. A distinctive feature of the model is the prediction of the reliability of combines, depending on the operating time since the start of operation. The initial data of the model is formed by the following indicators: cleaning conditions; consumer properties of combines; technological operating modes of combines when harvesting soybeans. The model provides for each combine harvester to determine performance indicators based on operating time. Based on this, the following are determined: the total operational productivity of combines and the duration of soybean harvesting without taking into account and taking into account delays due to weather conditions. Next, the technological losses behind each combine, the total losses of soybeans behind the combines, and the losses of soybeans by shedding during the period of operation after the agricultural period are modeled. As a result, the total soybean losses in the agricultural enterprise during the harvesting period are estimated. The simulation results make it possible to select the most favorable scenario for using combines in an enterprise from the point of view of minimizing losses.

Stochastic models of work and rest schedules

Purpose. To develop stochastic models for determining the duration of work and rest schedules that ensure protection of workers from occupational hazards and a high level of labor productivity during a work shift. Methodology. Analysis of scientific literature was applied to determine the purpose and tasks of the research; methods of formalization – to describe the characteristics, dynamics and states of random processes of accumulation and elimination of the consequences of the negative impact of harmful production factors occurring in an worker within the work and rest schedules; methods of semi-Markov processes theory, theories of reliability and recovery – to build stochastic models of work and rest schedules, determine the conditions and probability of a stable mode of their operation. Findings. Stochastic models were developed to determine the duration of work schedules, at the end of which the level of accumulation of the consequences of the negative impact of harmful production factors in the worker will not exceed the set maximum permissible values with a high probability. And such durations of rest schedules, at the end of which this level will be equal to zero (also with a high probability). The condition for ensuring the stable operation of these schedules throughout the entire period of work experience at the workplace was determined by the author. Originality. For the first time an approach to the development of work and rest schedules at workplaces is proposed, which, contrary to others, is based on determining the probabilities of the levels of accumulation of the consequences of the negative impact of harmful production factors in the worker at the end of these schedules, given the actual random and dynamic characteristics of such impact. This, in turn, allows ensuring the protection of the worker both from accidents caused by the fatigue and from professional illness. Practical value. The proposed approach allows increasing the economic efficiency of the enterprise by ensuring a high level of labor productivity, which is achieved by simultaneous development of the maximum possible duration of work and the minimum possible duration of rest schedules, which exclude the worker’s development and occurrence of fatigue and professional illness with a high probability.

DEVELOPMENT OF THE TECHNOLOGY OF CRANE-LESS LIFTING OF LONG-SPAN REINFORCED CONCRETE AND METAL COATINGS

Based on the analysis of well-known organizational-technological and structural-technical examples of crane-less lifting of long-span reinforced concrete and metal coatings of industrial and civil buildings, the goal was to develop a technological solution that would increase efficiency and shorten the duration of work on the construction of roofing structures. Taking into account the advantages and disadvantages of examples of the use of technologies of forced lifting of coatings by push-out methods, mechanized technological equipment for raising columns was developed, which consists of lifting modules and lifting fasteners. The lifting of the covering is carried out by leaning on the heads of the mounting columns, which are raised in the space between the paired design columns. In the process of increasing the load from the sections of the mounting columns, the support frames of the lifting modules and the lifting clamps take turns. According to the developed technological solution, in the initial phase, paired design columns are installed in the foundations by the method of free lifting with the help of cranes, and the construction and technological block of the covering is formed on low scaffolding. The support bars of the cover block are inserted into the space between the paired columns. Lifting modules and lifting fasteners are installed on the foundations, adjacent to the design columns. After completion of work on consolidation of the coating into a structural and technological unit, crane-less lifting of the coating to the design height is performed. For this, hydraulic lift cylinders raise the support frames and, fixed on them, the support bolts of the coating. Then the load from the coating is transferred to the lifting fasteners. At the next stage, the sections of the mounting columns are extended in the space between the columns. After lifting the covering to the design height with support on the mounting columns, the support bars of the covering are fixed on the heads of the design columns. Sections of mounting columns are dismantled. When using the developed technology, the lifting of the covering to a height of 34 m takes 1.8-2.0 shifts. At the same time, the dimensions of the construction site do not exceed the overall dimensions of the raised surface.