 High bond strength was obtained between cast iron and NiCrBSi powder coated by flame spray technique.  Hardness of coated sample was found to be approximately three times higher than that of cast iron sample.  The wear rate of the coated sample was found to be lower than the wear rate that of the lamellar graphite cast iron.  The surface roughness of the coated sample was seven times lower than that of the cast iron sample.

In this study, specific fuel consumption was determined at different axle load, tire pressure and drawbar force for a 60 HP tractor. In addition, the results were also estimated with the help of Artificial Neural Networks (ANN), which is one of the machine learning methods. The testings were carried out on the Tractor Draft Test Track. In the study; three different drive tire inner pressures (P) (160 kPa, 120 kPa and 80 kPa), four different dynamic axle loads (W) (1796 daN, 2076 daN, 2276 daN, 2476 daN) and four different traction forces (500 daN,1000 daN, 1500 daN, 2000 daN) were tested. Specific fuel consump-tion values varied between 290.7-542.1 g/kWh depending on the draft force in the testings Despite the 38% increase in the axle load, a 3.5% decrease occurred in the specific fuel consumption values. Specific fuel consumption values in-creased when increased tire inner pressure. Specific fuel consumption in-creased by 1.03% when a 100% increase in tire pressure. In ANN, the most suc-cessful model was determined by trying different training algorithms, transfer functions and the number of neurons in the hidden layer. In the most successful network model, MAE, RMSE values for the prediction of specific fuel consump-tion were found to be 0.005331, 0.007551 respectively.

Altın (Au) tarih boyunca insanoğlunun hep ilgisini çekmiş ve değerli bir metal olarak daima kullanılmıştır. Nano malzeme araştırmaları bilim dünyasının yoğun ilgi alanı içerisindedir. Nano altın partiküllerin (AuNPs) farklı ve şaşırtıcı özellikleri bu ilgiyi arttırmaktadır. Günümüzde altın nano partiküllerin üretimi, tıp, uzay, otomotiv, elektronik, tekstil, mücevher, gıda gibi çeşitli alanlardaki sayısız uygulamalarından dolayı çok yaygındır. Bu derlemenin amacı nano altın partikülleri ve bazı kullanım alanları hakkında genel bir bakış açısı sunmaktır. Derleme sonuçlarına göre, nano altın partiküllerin boyutuna ve şekline bağlı olarak makro boyuttaki altına göre çok farklı kimyasal, fiziksel, elektrik, optik ve mekanik özellikler gösterdiği tespit edilmiştir. Nano altın malzemeler ile ilgili çalışmalar her geçen gün hızla devam etmektedir. Bu alanda yeni ve ihtiyaca cevap verecek ürünlere ihtiyaç ortadadır. Bu çalışmaların organizeli ve kapsamlı olması için merkezi organizasyonlara ihtiyaç olduğu düşünülmektedir.

No abstract

New generation agricultural tractors contribute to transportation by increased travel speeds. There is not any available aerodynamic data on authentic agricultural tractor form. On-road transportation by tractors is between 8 to 30% of their operational time. In this work, two agricultural tractors are modelled via computational fluid dynamics for nine different speeds to determine aerodynamic resistances. Corresponding speeds are 10 to 80 km/h with 10 km/h increments and additionally 5 km/h. Reynolds number changes between 1.6×105 and 2.98×106. The characteristic lengths are taken as the square root of the streamwise projected area of the tractor geometries. Aerodynamic forces exerted on the tractors change between 3 N to 746 N. The calculated drag coefficients are found as independent from Reynolds number and are 0.6 and 0.78 for the two different types of driver compartments. Constant speed travel scenarios are analysed. The approximated aerodynamic related fuel consumptions for one-hour changes between 0.002 to 8.28 lt/s which correspond to 0.001 to 5.76 kg/s carbon emission. A potential improvement in decreasing aerodynamic resistance about 20% is discussed by spatial data. Since the conducted work is being regarded as the first instance in the literature, it is estimated that several consecutive reports will be triggered.