جستجوی مقالات مرتبط با کلیدواژه « ergonomics » در نشریات گروه « مکانیزاسیون کشاورزی »

The most important adverse effects of noise on humans have reduced work efficiency and physiological damaging effects such as increased heart rate, high blood pressure, permanent and temporary hearing loss, impaired vision, disrupting the body's balance system, causing nervous disorders and even nervous disorders. Much of the occupational disturbance is due to acoustic vibrations in agricultural mechanization, which is affecting a large number of farmers. In this regard, most of the noise and vibration come from two-stroke or four-stroke engines that are used in lawn mowers, sprayers, pits and more. These high-vibration equipment causes a great deal of damage to their operators. Portable lawn mowers are popular for working in urban and rural areas due to their low cost, low maintenance cost, high maneuverability and affordability. Therefore, the possibility of optimizing the muffler of a small combustion engine for a lawn mower was investigated and studied in the present stud.

To optimize the existing muffler, geometry of the factory muffler was first redesigned in solidworks 2014 software. Then the optimized muffler, along with the factory muffler exported into ANSYS CFX software and simulated in terms of velocity and pressure distributions. To evaluate the built muffler and compare its performance with the factory standard muffler, the mufflers were then mounted on a DOMA’s lawnmower model WPGD501 with a 42 cm3 engine volume and tested outdoors in a radius of 5 m. All sound recording tests were performed in steady state at a distance of 1m with a 45° angle and position along the exhaust outlet to reconstruct the user's ear position. A digital thermometer TEM-8820 and a PSA-V01 digital barometer were used to measure the sound pressure and an environment temperature.

The results showed that at 3000 rpm, the sound pressure level of the modified muffler decreased by 6.4% compared to the modified muffler. The same decrease in sound pressure level was achieved at 5000 rpm, equal to 4.5%. The results of this study showed that with increasing engine speed, pressure changes in the muffler had an upward trend. These changes in the modified muffler increased by 0.02 kPa at 3000 rpm and by 0.07 kPa at 5000 rpm. According to the outputs of the FFT diagrams, the intensity and amplitude of the output frequencies from the modified muffler significantly decreased almost at most frequencies. Therefore, effective pressure difference (ΔPrms) was used for the further investigations. The results of this study showed that the pressure changes in the muffler had an upward trend with increasing the engine speed. These changes in the modified muffler increased by 0.02 kPa at 3000 rpm and by 0.07 kPa at 5000 rpm.

According to the results of the present study, by optimizing the internal muffler geometry of the lawn-mowers by installing internal blades and neutralizing the sound intensity inside the muffler, it is possible to reduce the sound pressure level by 4% to about 7% over the original muffler. It is a very simple and inexpensive method for the manufacturers of such engines.

 Currently, musculoskeletal disorders are one of the most common occupational diseases and one of the most common causes of absenteeism, which leads to a decrease in productivity. Postural assessment methods are considered pivotal in the investigation of the risks of developing job-related musculoskeletal disorders. Various approaches are presented to assess the risk of injury in inappropriate postures. Agriculture is one of the most crucial sectors in both the developing and the developed countries since it ensures the food security of the country. In the process of producing sugarcane, a significant part of the stages of cutting, planting, and harvesting is done manually. A low level of knowledge about the correct condition of the body during work is one of the problems of farmers. Therefore, body status assessment methods are considered as the basis for assessing the risk of musculoskeletal disorders associated with work.

This research was carried out with the aim of analyzing the risk factors of occupational skeletal musculoskeletal injuries in sugar cane farmers using QEC method and Nordic questionnaire. The quick exposure checklist (QEC) quickly assesses the exposure to risks for work-related musculoskeletal disorders (WMSDs). QEC is based on the practitioners’ needs and research on major WMSD risk factors. The Nordic body map is given to the participants to be filled out with the assist of a student research assistant when needed. However, due to practical reasons, most participants are interviewed using the semi-structured method by a student research assistant. The Nordic body map consists of 28 parts of the body that must be rated based on the symptoms. Examples of the body parts are the right shoulder, upper arm, etc. The postures of 50 cutting workers, 200 planting workers, and 50 harvesting workers were selected by random sampling and analyzed using QEC2003 software.

 According to the results of the Nordic questionnaire in manual cutting sugarcane, the most prevalent signs of musculoskeletal disorders were in the waist (80%), wrists and hands (78%), knees (74%), and feet (70%). In manual planting sugarcane, the most prevalent signs of musculoskeletal disorders were in the areas of the waist (89%), back (86.5%), and knee (84.5%), respectively. The findings also indicate that in the manual harvesting operations, the most prevalent signs of musculoskeletal disorders were the wrist and hand (88%), waist (84%), and foot (80%). The results of the Nordic questionnaire show that most disadvantages of cutting, planting, and harvesting in workers are visible in the lower back (80%), lower back (89%), and wrist/hand (88%), respectively. The prevalence of skeletal musculoskeletal disorders, especially in the waist, was observed among a high number of sugarcane producers. The results also showed that in the QEC method, in cutting, planting, and harvesting 44, 62, and 59 percent of workers’ postures were placed in the most critical group. In manual cutting of sugarcane, 30 percent of the workers were at the high-risk level and 44 percent of workers were at high risk, indicating the high risk of this operation, and that better preventive measures should begin as soon as possible. In the QEC method for manual planting of sugarcane, 7% of the postures of workers is acceptable and their risk is very low. Work posture for 9.5% of people requires more research and attention, and 21.5% of workers must be treated fairly fast. 62% of the postures of workers need to be corrected promptly. In the QEC method for manual harvesting of sugarcane, the posture requires 14% more research and attention, and 28% of workers should be treated fairly quickly. For 59% of postoperative workers, work should be promptly corrected. The QEC analysis showed that some of the work postures posed greater risks of MSDs to the workers with QEC scores. QEC helps to prevent many kinds of WMSDs from developing and educates users about WMSD risks in their workplaces.

 The study has identified the body parts and tasks of the workers exposed to ergonomic risks through the Nordic questionnaire and the QEC method, respectively. Results from the study showed that the majority of the workers were having WMSDs.The physical condition of sugar cane production workers needs to be corrected. The ergonomic training course can have an impact on improving the working conditions of workers, but it is not enough, and it is a must-have for the sugar agro-industry to move towards all mechanized operations.

Musculoskeletal disorders due to inappropriate conditions in sugarcane Agro-Industry in Khuzestan province today are the reason for many human labor injuries in sugarcane fields. The risk of exposure to harmful agents to the musculoskeletal system is evaluated in a variety of ways such as REBA, RULA, QEC and OWAS. The aim of this study was to determine the number of musculoskeletal injuries and ergonomic evaluation of work situation by sugarcane cuttings planting, and harvesting using OWAS method. In this descriptive-analytical study, the workplaces of 20 groups of 10 workers were planted and 100 workers were cutting and harvested. Situations of workers were recorded in different situations. Then they were coded into different parts of the body based on their status according to the method studied and these codes were entered into the table and the final scores were calculated using winOWAS software. The results showed that cuttings harvesting, planting, and harvesting sugarcane were 36.37, 41.67% and 33.33%, respectively, in the most critical situation. The prevalence of musculoskeletal disorders among sugarcane production workers is significant. Based on the results, the main problems of ergonomics are included inappropriate physical condition, lifting and carrying heavy loads and bending of the waist.

Sugarcane with 110,000 hectares is one of the most important agricultural-industrial products in the country. Currently, a significant part of the sugarcane production process, such as cuttings, planting and harvesting, is done manually. Musculoskeletal complications are among the most commonly occurring complications in cane and other traditional agricultural environments. Among the various problem found in agriculture mentioned above, a problem commonly reported in agricultural workers in particular farmers in a rural area is work-musculoskeletal symptoms (MSS) in a different part of a body. A low level of knowledge about the correct condition of the body during work is one of the problems of farmers. Therefore, body status assessment methods are considered as the basis and basis for assessing the risk of musculoskeletal disorders associated with work. The aim of this study was to determine the prevalence of musculoskeletal disorders and risk assessment in the organs of sugarcane production workers in Khuzestan province. This cross-sectional study was carried out on 300 workers during the 2018-2019 crop year. The RULA method was used to determine the prevalence of musculoskeletal disorders and to assess the risk of these disorders. Data analysis was performed by Ergo Intelligence-UEA software. According to the RULA method, the cuttings, planting and harvesting were 28.69%, 20.56%, and 52.34% of workers' postures, respectively, in the most critical group. The need for ergonomic interventions in the RULA method is felt in sugarcane fields. A high percentage of musculoskeletal disorders in workplaces occur due to awkward posture and non-ergonomic design of the work stations for lifting and carrying of materials. To avoid these injuries, jobs should be designed in a way that ergonomics risk factors are controlled properly. These interventions primarily involve changing the production process from manual to mechanized, and further changing the work postures by considering access to work and proposing the right tools for doing work.

Nowadays, with progress in different sciences and entering logging software and decision-make systems, decision has been deviated from trial and error in agriculture mechanization and aimed to predict prospective and targeted accordingly. Therefore in this research, the Analytic Hierarchy Process (AHP) with the help of EXPERT CHOICE11 software was employed to select the most appropriate hole-digger for usage in gardens. Three different types of hole-diggers including manual hole-digger, hydraulic hole-digger and three point hitch hole-digger were evaluated in this study. The criteria of selection consisted of the device's price, maneuverability in confined space, ergonomics, ease of utilization and work progression. The importance of device's price, maneuverability in confined space, ergonomics, work progression and finally ease of utilization were equal to 0.366, 0.277, 0.168, 0.121 and 0.068, respectively. The manual hole-digger, which is the cheapest type of diggers, is selected and introduced with 0.403 final value among the three types of hole-diggers as the most appropriate choice option. Inconsistency ratio was calculated equal to 0.05 that is acceptable amount in saaty’s opinion.

Transmission of mechanical energy from vibration source to human body has different effects, such as reduced efficiency, skeletal lesions, disorder in the comfort, physiological and psychological problems. The lack of suspension systems on agricultural machines has causedthat the operators of agricultural machinery to be exposed to a wide range of vibrations indirectly. Use of suitable seat foam is one solution to reduce the vibrations. In this study, the vibration transmission of Polyurethane foam or sponge and effect of various factors for reducing vibrations is investigated. Therefore, different types of foam and sponge with a thickness of 6, 8, 10 and 12 cm, and densities of 12.5, 20, 30 and 50 kg/m3 were exposed to the vibration. Also the passenger mass and stimulation acceleration in three different levels were applied to the samples. Acceleration Data were records and the experimantal analyses were then performed with SPSS and MATLAB software. The results showed that vibration transmissibility of the cold foam was less than that of hot foam (about 10%). Considering the Anthropometrics data and the range of tractor operators mass in Iran (72-90 kg), and also due to the principles of ergonomics, the use of cold foam with a density of 50 kg/m3 (transferability of 26%), the thickness of 8-10 cm in acceleration of 3-4 m/s2 (transferability of 17%) is the most appropriate choice for the machines with high vibration seat.

This study was aimed to determine human and machine causes including musculoskeletal disorders for 399MF tractor drivers in Iran, Kohgiluyeh and Boyer Ahmad province (city of Yasouj, Dena, Dehdasht and Gachsaran). The data was collected by using musculoskeletal and aided Nordic questionnaire and analyzed by SPSS 21 software as well as independent T-test and (Chi-Square) X 2. The mean age of the study population, was noted to be 36.33, mean weight and mean height were 85.35 kg and 172.82 cm, respectively. it was found that 91.9% of studied drivers suffered at least once in one part of the body during 12 months. The most frequent injuries and disorders proved to be neck (83.54 %) and back (75.33%), respectively and the lowest was the feet and ankles (17.36 %). The results obtained from Rapid Entire Body Assesment (REBA) technique proved that in 20 investigated work condition, 13 cases were in a high dangerous status and 7 ones were in mid dangerous status which need special attention. Main ergonomic problems were the force exerted on the knee, bending and torsion force on the waist and neck. This study indicated that the prevalence of work-related musculoskeletal disorders of MF399 tractor drivers needs to be urgently modified.

Ergonomic design of workspace with considering the physical and physiological aspects, is expected to result in increasing the driver's satisfaction and decreasing undesired events. Driving the tractor induces vibrations and rotations to the driver's body which can lead to pain in the body joints. Therefore, a self-declaration questionnaire was designed and filled by 1200 tractor drivers. This questioner included three sections of personal and occupational information and the filed operations performed by the driver. After Collecting and classifying the information extracted from the questionnaire was analyzed with independent t and Chi-square tests. It was indicated that drivers had experienced pain in head and neck (39%), knee (37%), hips, arms and hands (29%), shoulders (28%), upper torso (26%), legs and ankles (25%), lower torso and thighs (24%) and in general, approximately 72% of the drivers had at least one or more than one organ feeling pain. Feeling discomfort after doing various agricultural operations caused increases in pain of some of joints related to the type of agricultural operation. Tillage operations showed a direct role in joint problems at a confidence level of 90%. The two-year study showed that the repetition of these disorders during the sequential years, has led to disability or irrecoverable disorders of joints

Different models of tractors have been imported from foreign countries or assembled in Iran for many years. Consistency of foreign manufactured products with native specifications and the improvement of locally manufactured tractors are important problems that must be considered. Moreover, tractor dimensions, sitting space and some other important factors such as the ability of Iranian users to operate them must be taken into consideration. In this study, we surveyed the proper proportion of tractors dimension, location of control tools and driver’s work space, with Iranian users’ anthropometric data of drivers from five provinces. Human factors are of paramount importance in developing farm machinery given that these machines will often be operated by persons with minimum skills. Therefore, farm machinery should be made simple to operate and as free from hazards as possible. Firstly, the anthropometric data for 250 users 20-60 years old was calculated. The drivers were selected randomly. Then the specifications of 4 tractors including: Ferguson 285, Ferguson 399, Valtra and New Holland were compared with the anthropometric data of user in 5th and 95th percentile value and their adaptation was studied. Anthropometric Data of subjects consisted of: standing height, full hand length, popliteal length, seat pan width, seat pan depth, elbow height, seat back support height, hand pan width, hand grip and full-leg length. Getting on the tractor is the first contact of an operator with a tractor. In assessing the suitability of the provision made for getting on the tractor, an experiment was arranged in which operators tried to get on 3 tractors. The mode of getting on the tractors, the agony on the operator’s face, the muscular reactions and individual opinion on the difficulties or comfort while undertaking the task were observed and recorded. The specifications of tractors compared with Anthropometric Data were measured, whiles the tractors were positioned on a level ground for measurements after the tires had been ganged. These specifications were tractor height, steering wheel height, footrest height, foot set height; tractor seat geometry as seat pan width, seat pan depth and seat pan support height; steering geometry as distance of steering wheel from seat reference point, steering wheel radius, steering wheel thickness, steering wheel inclination to the horizontal and seat reach adjustment; levers and pedals distance from seat reference point as gear lever, parking brake lever, hydraulic control lever, clutch pedal, accelerator pedal, brake pedal, front panel, workspace width and workspace length. The experiment that was conducted with operators attempting to get on the tractors indicated that tractor steps heights were higher than the desirable limit. Therefore, based on the ideas of the researcher and tractors drivers, getting on all tractors is difficult. With an increase in the number of steps or a decrease in their heights, the desirable condition can be created. Seat depth of new Holland and Valtra tractors were great for drivers in the 5th percentile value. A variable thickness pad can solve this problem. Results of studies indicated that Seat depth of Massey Ferguson 285 and 399 was shorter than driver’s leg length of 95th percentile value. To solve the problem an increase of 10 centimeters to pad height of these tractors was suggested. Seat pad of tractors were short for drivers in the 95th percentile value. Distance of steering wheel from seat reference point (SRP) in Massey Ferguson 285 and Valtra was further than drivers hand length in the 5th percentile value. Therefore, the drivers hand is short for driver’s good operation. Surveys indicated that drivers had problems for gear lever access in Massey Ferguson 399. Therefore, for good access on gear lever we must increase seat stroke range by 5-10 centimeters. The record available from Meteorological Organization indicated that air temperature and rain throughout the year in the study area is between 20 to 40degrees Celsius and 100to 300mm change. Valtra and New Holland tractors having a driver cabs with heating and cooling equipment have the ideal space for the performance of their driver. Massey Ferguson 285 tractor does not have any driver cab and Roll Over Protection Structure (ROPS). This research was conducted in five provinces of Iran to assess ergonomics of some commonly and new used tractors in Iran containing Ferguson 285, Ferguson 399, Valtra and New Holland. As there was no data base with required details, data was collected directly by personal contact with tractor users. A questionnaire was filled out for each person and anthropometric data was calculated in all provinces for 250 users 20-60 year old that were selected at random. Then relevant specifications of 4 tractors were measured and compared with the relevant anthropometric data of users in the 5th and 95th percentile value and their adaptation was studied. The results indicated that tractor steps, Seat depth, distance of steering wheel and distance of some levers and pedals from seat reference point should be amended.

This study was conducted among dates’ packinghouse workers with the objectives of a) determining of MSDs prevalence and b) evaluating level of exposure to MSDs risk factors. The results of this study can be used to develop MSDs preventive strategies in the workplace and improve workers’ health. This study was a descriptive- analytic approach performed on 98 workers at 6 activities and 29 working postures by using REBA method. The prevalence of MSDs was obtained by using Nordic Musculoskeletal Questionnaire (NMQ). The data were analyzed by independent t-test، Chi-square and proportions test with P<0. 05 as the limit of significance. The average of age and job tenure was 34. 9±14. 86 and 7. 01±5. 79 years، respectively. The 69. 4% of the workers suffered from some kind of symptoms during the last 12 months. The highest prevalence was reported in lower back (30. 6%)، knees (25. 5%) and ankles/feet (23. 5%). The result of REBA evaluation method showed that 19 postures were at average risk and in need of necessary corrective action and 4 postures were at high risk and possible correction actions were necessary. This study demonstrated that WMSDs occurred at a high rate in the study population. Major ergonomic problems were found to be awkward postures، manual material handling، back rotation and bending. Furthermore، based on the REBA results، implementation of interventional corrective measures to reduce level of workers'' exposure to WMSDs risk factors was essential.