Determination Of Reactivity Ratios In N-isopropylacrylamide And Itaconic Acid Copolymers

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2004Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2004Bu çalışmada itakonik asit (IA) ve N-izopropilakrilamid (NIPAAm) monomerlerinden farklı pH değerlerinde (pH=3 ve pH=5) hazırlanan kopolimerlerde reaktiflik oranları hesaplandı. Reaksiyon süresi, dönüşüm en fazla 15% olacak şekilde belirlendi. Kopolimerler sentezlendikten sonra bileşimleri kondüktometrik ve potansiyometrik titrasyon yöntemleri ile belirlenmiştir. Kalibrasyon eğrilerinin çizilmesi için önce PIA’in 0.1N NaCI içinde farklı konsantrasyonlarda çözeltileri hazırlandı. PIA çözeltilerinin titrasyonu potansiyometrik ve kondüktometrik metodlar kullanılarak 0.1N NaOH (F=0.9443) ile yapıldı. Dönüm noktaları için sarf edilen NaOH hacimleri PIA konsantrasyonuna karşı grafiğe çizildiğinde kalibrasyon eğrileri elde edildi. Kopolimerlerin 0.1N NaCI’de hazırlanan çözeltileri 0.1N NaOH ile titre edildi. Titrasyonda dönüm noktalarına karşılık gelen hacim değerleri, kullanılan yönteme uygun kalibrasyon eğrisinde işaretlenerek, kopolimerlerdeki IA bileşimi (FIA) bulundu. Finemann-Ross, Kelen-Tüdös, Genişletilmis Kelen-Tüdös, Mayo-Lewis doğrusal ile Tidwell-Mortimer doğrusal olmayan metodları kullanılarak reaktiflik oranları hesaplandı.Reaktiflik oranları beklendiği gibi değişiklik göstermiş ve pH=3’de IA daha aktif bir komonomer iken pH=5’de NIPAAm daha reaktif duruma geçmiştir.In this work the reactivity ratios of itaconic acid (IA) and N-isopropylacrylamide (NIPAAm) copolymers, prepared at different pH values (pH=3 and pH=5), was calculated. Reaction period was kept the conversion up to 15%. The mole fractions of copolymers were determined by using conductometric and potentiometric methods. Firstly, for plotting the calibration curve, the homo PIA was dissolved in 0.1N NaCI in different concentrations. These solutions were titrated by potentiometric and conductometric methods using 0.1N NaOH (F=0.9443). The volumes of the NaOH used in the inflection points versus PIA concentration were plotted in order to obtain the calibration curves. Prepared solutions of copolymers in 0.1N NaCI, titrated with 0.1N NaOH. The NaOH volume requested for the infection points were applied to the appropriate calibration curve to calculate the IA mole fraction (FIA) in the copolymers. Finemann - Ross, Kelen - Tudos, Extended Kelen - Tudos, Mayo - Lewis linear methods and Tidwell - Mortimer, non linear methods used to calculate the reactivity ratios of monomers. Reactivity ratios showed the change with increasing the pH value and IA is active monomer pH=3, while NIPAAm is the active one in pH=5.Yüksek LisansM.Sc

Spectrum compression

With recent technological developments in electronic warfare systems, there is an increase in the usage of data which should be transmitted. Due to the insufficiency in the system throughput, some problems such as latency or data loss may be seen. As a solution for these problems, data compression is offered. As one of the data which should be carried, spectrum can also be compressed. In this study, an algorithm for spectrum compression is offered. Moreover, real spectrum data are examined by comparing the efficiencies for each different variable

Nuclear Medicine Imaging in Pediatric Neurology.

Nuclear medicine imaging can provide important complementary information in the management of pediatric patients with neurological diseases. Pre-surgical localization of the epileptogenic focus in medically refractory epilepsy patients is the most common indication for nuclear medicine imaging in pediatric neurology. In patients with temporal lobe epilepsy, nuclear medicine imaging is particularly useful when magnetic resonance imaging findings are normal or its findings are discordant with electroencephalogram findings. In pediatric patients with brain tumors, nuclear medicine imaging can be clinically helpful in the diagnosis, directing biopsy, planning therapy, differentiating tumor recurrence from post-treatment sequelae, and assessment of response to therapy. Among other neurological diseases in which nuclear medicine has proved to be useful are patients with head trauma, inflammatory-infectious diseases and hypoxic-ischemic encephalopathy

Antenatal Diagnosis of Ambiguous Genitalia in a Fetus at 28th Gestational Week

To discuss an ambiguous genitalia case diagnosed antenatally. A fetus with ambiguous genitalia has been determined during US scan performed during 28th gestational week and confirmed with physical exam postnatally. External genitalia evaluation should be a part of routine anomaly screening as ambiguous genitalia can be life threatening issue especially in enzyme defects according to the deficient enzyme typ