Browsing by Author "Çağlar S."

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Effect of Different Production Methods on the Mechanical and Microstructural Properties of Hypereutectic Al-Si Alloys
(2014-10-01) Fatih Kilicaslan M.; Uzun O.; Yilmaz F.; Çağlar S.
In this study, the effects of different production methods like melt spinning, high-energy ball milling, and combined melt spinning and high-energy ball milling on the mechanical and microstructural properties of hypereutectic Al-20Si-5Fe alloys were investigated. While microstructural and spectroscopic analyses were performed using scanning electron microscopy and X-ray diffractometry, mechanical properties were measured using a depth-sensing indentation instrument with a Berkovich tip. Microstructural and spectroscopic analyses demonstrate that high-energy ball milling process applied on the melt-spun Al-20-Si-5Fe alloy for 10 minutes brings about a reduction in the size of silicon particles and intermetallic compounds. However, further increase in milling time does not yield any significant reduction in size. High-energy ball milling for 10 minutes on the starting powders is not enough to form any intermetallic phase. According to the depth-sensing indentation experiments, high-energy milling of melt-spun Al-20Si-5Fe alloys shows an incremental behavior in terms of hardness values. For the Al-20Si-5Fe alloys investigated in this study, the production technique remarkably influences their elastic–plastic response to the indentation process in terms of both magnitude and shape of P-h curves.
Productivity analysis of tree-length harvesting using farm tractor in a nordmann fir stand in Turkey
(2021-01-01) Çağlar S.; Sadık ÇAĞLAR
Because of the low investment costs, the winch equipped farm tractors usage is the most common logging technique for the primer transportation of wood-based forest products in Turkey. During the logging operations, farm tractors are commonly used for cable winching at a steep terrain while they are used for skidding operation on relatively flat terrain conditions in forest stands. The aim of this study was to evaluate the working conditions and determine the productivity of uphill winching using a farm tractor during tree length harvesting operation in a Nordmann fir stand (Abies nordmanniana). The study was conducted in Western Black Sea Region of Turkey. The average diameter and length of the forest products which were hauled from stump-site to landing areas were 17 cm and 28 m, respectively. The winching distances were ranged from 10 m to 70 m. Time analysis and field measurements related to independent variables (including winching distance, tree diameter, length and volume) were conducted while the farm tractor was winching the harvested forest products. For the farm tractor, the productivity was estimated and the cycle time prediction model was developed using the multiple regression method. It was found that the average hourly and daily productivity were 5.80 m3/hour and 46.42 m3/day for 8 hours, respectively. The most time consuming work element was winching (49.2%), followed with delay time (20.1%).
Productivity analysis of tree-length harvesting using farm tractor in a nordmann fir stand in Turkey
(2021-01-01) Çağlar S.
Because of the low investment costs, the winch equipped farm tractors usage is the most common logging technique for the primer transportation of wood-based forest products in Turkey. During the logging operations, farm tractors are commonly used for cable winching at a steep terrain while they are used for skidding operation on relatively flat terrain conditions in forest stands. The aim of this study was to evaluate the working conditions and determine the productivity of uphill winching using a farm tractor during tree length harvesting operation in a Nordmann fir stand (Abies nordmanniana). The study was conducted in Western Black Sea Region of Turkey. The average diameter and length of the forest products which were hauled from stump-site to landing areas were 17 cm and 28 m, respectively. The winching distances were ranged from 10 m to 70 m. Time analysis and field measurements related to independent variables (including winching distance, tree diameter, length and volume) were conducted while the farm tractor was winching the harvested forest products. For the farm tractor, the productivity was estimated and the cycle time prediction model was developed using the multiple regression method. It was found that the average hourly and daily productivity were 5.80 m3/hour and 46.42 m3/day for 8 hours, respectively. The most time consuming work element was winching (49.2%), followed with delay time (20.1%).