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    Failure rate analyses of cereal combined drills
    (Academic Journals, 2011) Say, Sait M.; Sumer, Sarp K.
    Machine availability estimations from research performed before the following season are needed to decide on the required machinery size necessary for timely operation. Additionally, estimations on machinery availability will provide useful data for making mathematically proven assumptions regarding the repair maintenance and timeliness costs. Machine reliability or operational availability analyses must be carried out, especially for combine drills and combine harvesters, which are relatively more sensitive to timeliness. In the literature, there is rare study on operational availability on combine drills. In this study, failure rates, which are a direct indication of machine operational availability, were evaluated from the farm records of cereal combine drills used in Adana, which is located in Cukurova, one of the major agricultural regions in southern Turkey. These records for combine drills of different ages and with different annual use hours were collected during three subsequent years. Moreover, different repair and maintenance policies in farms under examination were considered. As a result, it was found that different accumulated use hours and repair-maintenance policies have slightly affected failure rates. According to the data, the combine drills included in this study are commonly in a randomized breakdown period within their useful life.
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    Noise exposed of the operators of combine harvesters with and without a cab
    (Elsevier Sci Ltd, 2006) Sumer, Sarp Korkut; Say, Sait M.; Ege, Fikri; Sabanci, Alaettin
    A considerable number of the combine harvesters in Turkey are rather old and used without cabs resulting in unhealthy working conditions for their operators. Noise is one of the detrimental factors. This study deals with determining and comparing the noise exposed on the operators of the combines with and without a cab used for wheat harvesting in Turkey. The sound pressure levels (dB) at octave band center frequencies (31.5-8000 Hz) and the sound levels (dBA) at the ear level of the operators were measured on 37 different combine harvesters with four different makes and different years from 1976 to 2001. Fifteen of the combines were without a cab, another 15 had original cabs while remaining seven combines had cabs mounted on them after manufacturing. The sound pressure levels were in a decreasing trend from the lower frequencies to higher frequencies. This trend was more noticeable for the combines with original cab and with the cab mounted after manufacturing compared to the ones without cab. The use of a cab was more effective in the insulation of the noise at the medium and higher frequencies, which have more bothersome effect compared to the lower frequencies. The sound pressure levels were 75-102 dB and 46-89 dB at low (31.5-500 Hz) and high (500-8000 Hz) frequencies for all combines, respectively. The sound pressure levels at the frequency of 400OHz at which the human ear is most sensitive were 6-17 dB lower for the combines with the cabs mounted after manufacturing and 9-28 dB lower for the ones with the original cabs compared to the combines without cab. The sound levels were 85-90, 81-83, and 76-81 dBA for the combines without cab, with cab mounted after manufacturing, and with original cab, respectively. The study showed that the use of a cab was useful in the insulation of the noise, particularly at higher frequencies. In addition, it protects the operator from the factors having detrimental effects on the working efficiency such as high temperature and dusty environment. The authors strongly recommend mounting of a cab on to the combines currently being used without a cab in rental system in Turkey to provide healthy working conditions for their operators. (c) 2006 Elsevier Ltd. All rights reserved.