Browsing by Author "Peker, Ahmet"
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Item İç Anadolu koşullarına uygun patates hasat makinalarında sökücü elemanların ve iletici organların yapısal özelliklerinin geliştirilmesi(Fen Bilimleri Enstitüsü, 1990) Peker, Ahmet; Gökçebay, BahriBu çalışmada, sökücü iletici tip patates hasat makinalarının kazıcı ve eleyici organları ele alınmıştır. Kazıcı ve eleyicilerin çalışma koşullarını etkileyen faktörler üzerinde özellikle durulmuştur. Bu amaçla 22, 27 ve 32 dalma açılarında üç adet parçalı tip kazıcı projelenerek prototip olarak üretilmiştir. Denemeler tarla koşullarında gerçekleştirilmiştir. Denemelerde ilerleme hızı, kazıcı dalma açısı ve elevatör hızı faktörlerinin kazıcının ve elevatörün çalışma koşullarına etkileri incelenmiştir. Ele alınan faktörlerin etkilerini belirlemede çeki kuvveti ve çeki gücü, yumru zedelenmesi, hasat kayıpları ve yakıt tüketim kriterlerinden yararlanılmıştır. Çeki kuvveti değerleri, özel olarak hazırlanan bir ölçme düzeni ve buna bağlanan elektronik cihazlar yardımıyla saptanmıştır. Hasat kayıpları ve yakıt tüketimi değerleri tarlada ölçülmüştür. Yumru zedelenmesi, örnekler tarlada alındıktan 72 saat sonra laboratuvarda değerlendirilerek saptanmıştır. Çalışmalar sonucunda incelenen üç faktörün her seviyesinin ayrı ayrı ve birlikte etkileri belirlenerek, çalışma koşullarını en olumlu şekilde etkileyen kombinasyon ortaya konulmuştur.Abstract In this study, the share and sifting units of digger and elevator type potato harvesters have been examined. The factors effecting the working conditions of the share and sifting have been especially emphesized. For this purpose, three types of pieces o o o shares where angle <<= 22, 27 and 32 have been planned as the prototype and manufactured. The experiments have been realized in field conditions. In these experiments, the influence of forward Speed, angle o^ and elevator speed on the working conditions of share and elevator have been studied. In the determination of the effect of these factors the criteria of draft requirement and draft power, tuber damage, harvest losses and fuel consumption have been used. The data of draft requirement have been determined by means of a measuring aparatus with electronic measurement equipments. The data of harvest losses and fuel consumption have been measured in the field. The damages on the tubers have been determined in the laboratuary for 72 hours after they were taken from the field. As a result, the combination which has effected the working conditions most favourably have been found out by specifying the effects of each level of three factors both separately and togather.Item The role of baseline Ga-68 DOTATATE positron emission tomography/computed tomography in the prediction of response to fixed-dose peptide receptor radionuclide therapy with Lu-177 DOTATATE*(2016-02-17) Soydal, Cigdem; Peker, Ahmet; Özkan, Elgin; Küçük, Nuriye Özlem; Kır, Kemal Metin; Tıp FakültesiBackground/aim: To describe the role of baseline gallium (Ga)-68 DOTATATE positron emission tomography (PET)/computed tomography (CT) in the prediction of the response to peptide receptor radionuclide therapy (PRRT) using lutetium (Lu)-177 DOTATATE. Materials and methods: Analysis was made of baseline Ga-68 DOTATATE PET/CT images of 29 patients (17 females and 12 males; mean age: 50.7 ± 14.6 years) with metastatic neuroendocrine tumors who received PRRT with Lu-177 DOTATATE. Maximum standardized uptake values (SUVmax) of reference lesions and their ratios to physiological uptake organs were calculated. The relationship between these values and the radiological response was analyzed. Results: Partial response was observed in 8 (28%) patients, stable disease in 18 (62%) patients, and progressive disease in 3 (10%) patients. Mean SUVmax of reference lesions was calculated as 23.8 ± 20.5 (min-max: 5.1-87.3). There was no significant correlation between radiological responses and SUVmax of reference lesions and their ratios to other organs. Conclusion: Baseline Ga-68 DOTATATE PET/CT helps to show somatostatin receptor expression status and disease stage in patients who are candidates for PRRT. However, SUVs do not have a role in the prediction of treatment response.