Özkan, Ömer

Other | 2003 | Pamukkale Üniversitesi Mühendislik Fakültesi Mühendislik Bilimleri Dergisi9 ( 1 ) , pp.73 - 78

1999 yılında meydana gelen depremler sonrasında, kıyı şeridinde bulunan şehirlerde yapı malzemesi olarak kullanılan betonun karışımında deniz kumunun kullanılmasının beton mukavemetine ve dayanımına etkisi tartışılmaya başlanmıştır. Bu çalışmada Zonguldak-Alaplı bölgesinde denizden çıkarılan kum ile Zonguldak-Alaplı Çay'ından çıkarılan kumun mukavemetlerinin zamana göre değişimleri karşılaştırılmıştır. Kullanılan ince agregada birim ağırlık, özgül ağırlık, ince madde oranı, organik madde oranı tayin edilerek, incelik modülü deneyleri yapılmıştır. Yapılan deneyler neticesinde denizden çıkarılan kumun mukavemeti ortalama % 34 oranında . . . düşürdüğü tespit edilmiş olup bunun da kumun içeriğinden kaynaklandığı sonucuna varılmıştır. In the aftermath of massive earthquakes in 1999, the use of sea sand in the construction material as o substance has been widely questioned as it may have negative side effects on endurance strength of buildings in coastal cities. In this study, the change in the endurance of the concrete has been tested by the use of sea and river sand types from Zonguldak-Alaplı region. Some experiments concerning unit weights, absolute weights, and ratio of fine material and organic material ratio of sand types were also executed. As a result of experiment made about special features of the sand types, it is well understood that the endurance strength of concrete consisting of sea sand is 34% less than that of the normal sand due to tire changes in ingredients of sand types Daha fazlası Daha az

Özer, Mahmut

Other | 2003 | Pamukkale Üniversitesi Mühendislik Fakültesi Mühendislik Bilimleri Dergisi9 ( 3 ) , pp.349 - 356

Bu makalede, iyonik kanal aktivasyon ve inaktivasyon kapılarının dinamik davranışı için yol ihtimaliyet yöntemine dayalı olarak elde edilen alternatif denklemler sunulmaktadır. Gerilim-kapılı iyonik kanalın dinamik davranışı, geleneksel Hodgkin-Huxley (H-H) matematiksel biçimciliği ile modellenmektedir. Bu modelde kanal iletkenliği, aktivasyon ve inaktivasyon kapılarına göre tanımlanmaktadır. Aktivasyon ve inaktivasyon kapılarının dinamiği, kapı değişkenine ve membran potansiyeline bağlı birinci dereceden diferansiyel denklemlerle modellenmektedir. Bu çalışmada sunulan yeni yaklaşımda, aktivasyon ve inaktivasyon kapısının dinamik da . . .vranışı, istatistik fizikte yaygın olarak kullanılan yol ihtimaliyet yöntemi kullanılarak iç enerji ve membran potansiyeline bağlı birinci dereceden diferansiyel denklemlerle modellenmektedir. Yeni model, H-H modelinde açıkça kullanılan zaman sabiti ve sürekli-hal değerlerini de gerektirmemektedir. Sayısal sonuçlar önerilen yöntemin geçerliliğini göstermektedir. In this paper, alternative equations for dynamics of ionic channel activation and inactivation gates are proposed based on the path probability method. Dynamic behavior of a voltage-gated ionic channel is modeled by the conventional Hodgkin-Huxley (H-H) mathematical formalism. In that model, conductance of the channel is defined in terms of activation and inactivation gates. Dynamics of the activation and inactivation gates is modeled by first-order differential equations dependent on the gate variable and the membrane potential. In the new approach proposed in this study, dynamic behavior of activation and inactivation gates is modeled by a first-order differential equation dependent on internal energy and membrane potential by using the path probability method which is widely used in statistical physics. The new model doesn't require the time constant and steady-state values which are used explicitly in the H-H model. The numerical results show validity of the proposed method Daha fazlası Daha az

Yüksel, İsa

Other | 2003 | Pamukkale Üniversitesi Mühendislik Fakültesi Mühendislik Bilimleri Dergisi9 ( 2 ) , pp.231 - 235

Kızgut, Sait | Çuhadaroğlu, Dilek | Toroğlu, İhsan

Other | 2003 | Turkish Journal of Chemistry27 ( 4 ) , pp.521 - 528

This study focused on the thermal gravimetric characterization of Turkish bituminous coals for combustion. The combustion properties considered were based on the burning profile of coal samples and their chars produced in a PL 1500 TGA apparatus. The coal seam samples used in the study were obtained from TTK (Turkish Hardcoal Enterprise) mines as channel samples. The majority of the samples from 12 seams were medium-volatile bituminous and only three of them were high-volatile bituminous. Combustion profile parameters of coal samples and chars were correlated with petrographic, proximate and ultimate analysis data in order to establ . . .ish the combustion differences of the samples. The results indicated that only the combustion profile parameters of ignition and burnoff temperatures of coal were correlated with H/C ratio, fuel ratio and petrofactor. The amount of total reactive macerals showed a strong relationship with char reactivity for the same rank coal samples. However, the same result was not obtained for the whole range of coal samples, since rank effect was not included. The petrofactor, combining both effects of petrographic composition and reflectance data, showed a strong relationship with char reactivity for the whole range of coal samples. This study focused on the thermal gravimetric characterization of Turkish bituminous coals for combustion. The combustion properties considered were based on the burning profile of coal samples and their chars produced in a PL 1500 TGA apparatus. The coal seam samples used in the study were obtained from TTK (Turkish Hardcoal Enterprise) mines as channel samples. The majority of the samples from 12 seams were medium-volatile bituminous and only three of them were high-volatile bituminous. Combustion profile parameters of coal samples and chars were correlated with petrographic, proximate and ultimate analysis data in order to establish the combustion differences of the samples. The results indicated that only the combustion profile parameters of ignition and burnoff temperatures of coal were correlated with H/C ratio, fuel ratio and petrofactor. The amount of total reactive macerals showed a strong relationship with char reactivity for the same rank coal samples. However, the same result was not obtained for the whole range of coal samples, since rank effect was not included. The petrofactor, combining both effects of petrographic composition and reflectance data, showed a strong relationship with char reactivity for the whole range of coal samples Daha fazlası Daha az