Yolaðý kavramý ve trafik akým denge koþullarý kýsaca ele alýnýp incelenmiþtir. Kitleye (örneðin tüm yolaðýna) Sistem Optimumu yaklaþýmýnýn kullanýlmasý ile bazý yararlarýn kazandýrýlýp kazandýrýlmayacaðý, Ýstanbul yolaðý üzerindeki gerçek veriler kullanýlarak irdelenmiþtir. Sistemi optimize eden simulasyon, Kullanýcý Dengesi atamasýnýn sonuçlarýna nazaran, Boðazici Köprüsü üzerindeki kuyruklanma sürelerinde %12’lik bir düþüþ, ortalama araç hýzlarýnda %16’lýk bir artýþ ve ayrýca toplam sistem yolculuk sürelerinde ise yaklaþýk %4’lük bir azalma vermiþtir.

The concept of road networks and traffic flow equilibrium conditions are briefly reviewed and discussed. In order to see whether some benefits for the society (e.g. whole network) by employing a System Optimum assignment approach can be achieved or not, an assessment study was carried out on the Ystanbul road network using the actual data gathered. As a result of the system optimising simulation, queuing times on the Bosphorus Bridge dropped by 12% and speed of an average car increased by 16%, compared to the results produced by the User Equilibrium assignment. Besides, the total system journey time was also reduced by about 4%.

Bu çalýþmada çeki demirindeki gerilme analizi sonlu elemanlar metoduyla yapýlmýþtýr. Sonlu eleman modelinin kurulmasýnda dört düðümlü izoparametrik elemanlar kullanýlmýþ olup interpolasyon fonksiyonu olarak ise Lagrange polinomlarý alýnmýþtýr. Eleman aðýnýn oluþturulmasý için ayrý bir proðram yapýlmýþ ve elemanlar otomatik olarak elde edilmiþtir. Sonlu elemanlar için de özel bilgisayar proðramý geliþtirilmiþtir. Ele alýnan çeki demirinde artýk gerilmeleri hesaplayabilmek için elasto-plastik gerilme analizi yapýlmýþtýr. Elasto plastik gerilme analizinde yüklemeler 400 daN’dan 1000 daN’a kadar 100 daN’luk artýþlarla yüklenerek gerilme deðerleri hesaplanmýþtýr. Bu analizde “Baþlangýç gerilmesi metodu” kullanýlmýþtýr.

In this study, stress analysis has been done in Hooke’s joint by the finite element method. In finite element meshing, isoparametric quadrilateral elements with four nodes has been chosen and Lagrange polynomial has been used as the interpolation function. The special computer program has been written for the automatic mesh generation. In addition the other program has been developed to solve the finite element problems. Elastoplastic stress analysis is done to calculate the residual stresses in hooke’s joint. Elasto-plastic stress values are calculated under loading from 400 daN to 1000 daN with increment of 100 daN. In this analysis “The initial stress method” is used.

Bu çalýþmada atýk ýsý geri kazaným sistemlerinde verimli kullanýmlarý nedeniyle, çapraz akýmlý levhalý tip ýsý deðiþtirgeci araþtýrýlmýþtýr. Bu amaçla bir ýsý geri kazaným sistemi geliþtirilmiþ ve laboratuvar þartlarýnda imal edilmiþtir. Ýmal edilen ýsý deðiþtirgeci uygun bir deney düzeneði ile test edilmiþ ve sýcaklýk, hava hýzý ve sistemdeki basýnç kayýplarý ölçülmüþ, sistemin etkinliði belirlenmiþtir. Ayrýca tasarým esnasýnda ýsý deðiþtirgecinin tersinmezliði de gözönünde tutulmuþtur. Bunun için Termodinamiðin II. kanununa göre; çapraz akýmlý ýsý deðiþtirgecinde, minimum entropi üretim birimi analiz edilmiþtir. Minimum entropi üretim birimi; optimum akýþ yolu uzunluðu, boyutsuz kütle hýzý ve boyutsuz ýsý transfer alaný gibi parametrelere baðlýdýr. Entropi üretim biriminin bu parametrelerle deðiþimleri incelenerek, grafikleri yorumlarýyla sunulmuþtur.

In this study, cross-flow plate type heat exchanger has been investigated because of its effective use in waste heat recovery systems. For this purpose, a heat regain system has been investigated and manufactured in laboratory conditions. Manufactured heat exchanger has been tested with an applicable experimental set up and temperatures, velocity of the air and the pressure losses occuring in the system have been measured and the efficiency of the system has been determined. The irreversibility of heat exchanger has been taken into consideration while the design of heat exchanger is being performed. So minimum entropy generation number has been analysied with respect to second law of thermodynamics in cross-flow heat exchanger. The minimum entropy generation number depends on parameters called optimum flow path length, dimensionless mass velocity and dimensionless heat transfer area. Variations of entropy generation number with these parameters have been analysied and introduced their graphics with their comments.

Bu çalýþmanýn amacý; aktif elektronik devre elemanlarý için geliþtirilen nullor modelinin tanýtýlmasýdýr. Bu sebeple, transistör, ideal ve ideal olmayan iþlemsel kuvvetlendirici (op-amp) gibi bazý elektronik devre elemanlarýnýn nullor modelleri ve bu modelin negatif empedans çeviricisi, gyrator, çeþitli kontrollü kaynaklar ve aktif RC devre sentezindeki kullanýmlarý verilmiþtir. Bu konulara deðinilirken, nullor’un tercih edilme sebepleri ve saðladýðý yararlar üzerinde de durulmaktadýr.

The aim of this paper is to introduce the nullor model which is developed for active electronic circuit components. Therefore, nullor models of some electronic devices such as transistor, ideal and nonideal operational amplifiers are given. Applications of this model to negative impedance converters, gyrator, various controlled sources and the active RC circuit synthesis are presented and also the advantages of using this model are discussed.

Klasik elektromagnetik teoriye göre, ivmelendirilmiþ bir yük veya yük sistemi elektromagnetik radyasyon yayar. Bir radyo vericisinin antenindeki yükler anten boyunca ivmelendirilerek, antenin bulunduðu ortamda, ýþýk hýzýyla yayýlan elektromagnetik radyasyon elde edilmektedir ve bugünkü radyo vericilerinn hepsi bu prensibe göre çalýþmaktadýr. Bu çalýþmada ivmelendirilmiþ yük sistemlerinin radyasyon yayma ilkeleriyle, ivmelendirilmiþ madde sistemleri arasýnda bir benzetme yapýlarak, gravitasyona neden olan sistemler araþtýrýlmýþtýr.

According to classical electromagnetic theory, an accelerated charge or system of charges radiates electromagnetic waves. In a radio transmitter antenna charges are accelerated along the antenna and release electromagnetic waves, which is radiated at the velocity of light in the surrounding medium. All of the radio transmitters work on this principle today. In this study an analogy is established between the principles by which accelerated charge systems markes radiation and the accelerated mass system, and the systems cousing gravitational radiation are investigated.

Araþtýrmada, keçi etine farklý seviyelerde (%0.00, % 0.25, % 0.50) K2 HPO4 ve (% 2.5, % 3.0) NaCl ile birlikte iki ayrý sýcaklýkta (11o C ve 18o C) mýsýrözü yaðý ilave edilerek oluþturulan emülsiyonlarýn çeþitli özellikleri model sistemde araþtýrýlmýþtýr. Oluþturulan emülsiyonlarýn; emülsiyon kapasitesi (EK), emülsiyon vizkositesi (EV), emülsiyon stabilite oraný (ES), emülsiyondan ayrýlan su oraný (ESO), emilsüyondan ayrýlan yað oraný (EYO) ve emülsiyon pH deðerleri tespit edilmiþtir. EV ve ES üzerine K2 HPO4, NaCl ve yað sýcaklýðý istatistiki olarak çok önemli (p<0.01) etkiye sahip olurken, EK ve EYO üzerine sadece K2 HPO4 ve NaCl seviyesinin çok önemli (p<0.01) etki ettiði görülmüþtür. Ýlave edilen fosfat ve tuz seviyesi arttýkça EK, EV, ES yükselirken, en yüksek EK, EV ve ES deðerlerini 11o C’de % 3.0 NaCl, % 0.50 K2 HPO4 kombinasyonu göstermiþtir. En düþük EV deðeri 18 o C’de, % 2.5 NaCl, % 0.00 K2 HPO4 kombinasyonunda saptanmýþtýr. ESO üzerine; K2 HPO4, NaCl ve yað sýcaklýðýnýn, EYO üzerine ise K2 HPO4 x NaCl kombinasyonunun istatistiki olarak çok önemli (p<0.01) etkiye sahip olduðu görülmüþtür. Genel olarak; ilave edilen K2 HPO4 ve NaCl seviyesi arttýkça ESO ve EYO azalmýþtýr. Emülsiyon oluþturulmasýnda K2 HPO4 ve NaCl ilavesi emülsiyonlarýn pH deðerini yükseltmiþtir.

Different levels of K2 HPO4 (0.00 %, 0.25 % and 0.50 %) and NaCl (2.5 % and 3.0 %) were added into goat meat, at the two different temperatures (11o C and 18o C) in order to investigate the emulsion properties in the model emulsion system. Emulsion capacity (EK), emulsion viscocity (EV), emulsion stability ratio (ES), the ratio of separated water (ESO) and oil (EYO) ratio from the emulsion, and the emulsion pH were determined. K2 HPO4 and NaCl levels and the oil temperatures have significant effect (p<0.01) on EV and ES values, K2 HPO4 and NaCl levels only have significant effect on EK and EYO. As the phosphate and salt addition level increased, EK, EV and ES increased. The lowest EV was seen at 18o C with 2.5 % NaCl and 0.00 % K2 HPO4 NaCl addition and oil temperature on ESO and K2 HPO4 x NaCl combination on EYO have significant effect (p<0.01). In general, as K2 HPO4 and NaCl additions increased, the ESO and EYO ratios decreased, Ph values were incereased by the K2 HPO4 and NaCl additions.

Sera koþullarýnda perlitte Ruakura besin çözeltisiyle yetiþtirilen buðday (Triticum aestivum L.) bitkisine, artan düzeylerde uygulanan bor ile azotun, bitkinin geliþmesi ile bor, azot ve nitrat kapsamlarý üzerine etkileri araþtýrýlmýþtýr. Ruakura besin çözeltisine bor, borik asitten (H3 BO3) sýrasýyla 0.01, 0.1, 1.0 ve 10.0 µg B/ml, azot ise amonyum nitrattan (NH4 NO3) sýrasýyla 25, 100, 200 ve 400 µg N/ml düzeylerinde uygulanmýþtýr. Artan miktarlarda uygulanan bor, buðday bitkisinin kuru madde miktarýný ve nitrat kapsamýný azaltýrken, bor kapsamýný artýrmýþtýr. Azot uygulamasý ise deneme bitkisinin kuru madde miktarýný, azot ve nitrat kapsamlarýný artýrýrken, bor kapsamýný azaltmýþtýr. Bor ve azotun bu etkileri istatistiki yönden önemli olmuþtur (P<0.01). Yüksek dozlarda azot uygulamasý bitkide bor toksisitesini hafifletmiþtir. Düþük bor düzeylerinde ise bitkide nitrat biriktiði belirlenmiþtir.

The effects of boron applied 0.01, 0.1, 1.0, and 10.0 µg B/ml levels as boric acid (H3 BO3), and nitrogen applied 25, 100, 200, and 400 µg N/ml as ammonium nitrate (NH4 NO3), respectively, on the amount of dry matter yield, and boron, nitrogen and nitrate contents of wheat (Triticum aestivum L.) grown in perlite medium with Ruakura nutrient solution under greenhouse conditions were investigated. Dry matter yield and nitrate contents of wheat were decreased and boron content was increased with increasing boron application. Controversially, application of nitrogen increased dry matter yield, nitrogen and nitrate contents of wheat, while decreases in boron contents. Those effects of boron and nitrogen were found to be statistically significant (P<0.01). It was determined that addition of high levels of nitrogen alleviated boron toxicity. Low-level boron application caused in nitrate accumulation in plants.

Bu çalýþmada Etibank Fosfor Zenginleþtirme Tesislerinden çýkarýlan fosforlu materyalin doðrudan ve yarý yakýlarak fosfor kaynaðý olarak kullanabilme olanaklarýný araþtýrmak amaçlanmýþtýr. Asit ve nötr reaksiyonlu iki toprakta yürütülen sera denemesinde 6 kg toprak alan saksýlarda ön bitki olarak 5.5 aylýk süre ile yulaf (Avena Sativa), ikinci bitki olarakta 2 ay süre ile kolza (Brassica napus) yetiþtirilmiþtir. Saksýlara 1.2 g N (NH4 NO3), 1.5 g K2 O (K2 SO4), 1g P2 O5 sýrasýyla, TSP, ince atýk (Ý.A), Kaba atýk (K.A), yarýyanmýþ ince atýk (Y.Y.Ý.A) ve yarýyanmýþ kaba atýk (Y.Y.K.A) olarak uygulanmýþtýr. Araþtýrmada hamfosfat atýklarýnýn bitkilerin kurumadde, fosfor içeriði ve sömürdüðü fosfor miktarlarý üzerine etkileri belirlenmiþtir. Araþtýrmada, hamfosfatlarýn ön bitki ve ikinci bitkinin kuru madde ile fosfor kapsamlarý üzerine etkileri topraklar ve atýklar arasýnda önemli ayrýmlý bulunmuþtur. Yarýyanmýþ kaba atýk fosfor kaynaðý olarak topraklarda TSP ye yakýn etki gösterirken bunu kaba atýðýn doðrudan uygulamasý izlemiþ, ince atýðýn ise gerek doðrudan gerekse yarýyanmýþ uygulamasý en düþük etkiyi göstermiþtir.

In this study, it was aimed to research the possibilities of direct and acidulated usage of phosphate containing material which was obtained from Etibank Phosphate Enrichment Systems. In the greenhouse experiment, acid and neutr-characterized soils were used. Both oat (Avena Sativa) as a preliminary plant with the period of 5.5 months and rape (Brassica napus) as a second plant with the period of 2 months were grown in 6 kg soil containing pots. 1 g P2 O5 was given to pots in the forms of TSP, fine residue, coarse residue, acidulated fine residue and acidulated coarse residue. Additionally, 1.2 g N (NH4 NO3), 1.5 g K2 O (K2 SO4) were applied to the pots. The effects of rock phosphate on dry weight, phosphorus content and phosphorus uptake of plants were determined. According to the results obtained, it was concluded that the effects of rock phosphate on dry weight, phosphorus contents and amount of phosphorus uptake of both plants were found differently. Depending on soils and residues as a phosphate source the effect of acidulated coarse residue on soils was similar to that of TSP when compared with the effect of TSP on soils, that of direct application of coarse residue was lower and that of the acidulated and direct application of fine residue was the lowest.

Bu çalýþmada yavaþ kum filtrelerinin dizayn ve iþletme parametreleri, giriþ suyu kalitesi ile çýkýþ suyu kalitesi arasýndaki baðýntýyý ifade eden bir regrasyon modeli geliþtirmek amaçlanmýþtýr. Gerekli verileri sistematik ve karþýlaþtýrýlabilir þartlar için elde etmek üzere laboratuvar ölçeðinde üç yavaþ kum filtresi yapýlmýþtýr. Filtreler iki yýlý aþkýn bir zaman sürekli olarak çalýþtýrýlmýþtýr. Her bir filtre deðiþik etkin dane çaplý kum yataðýna sahiptir. Filtreler üç deðiþik sabit sýcaklýkta ve herbir sýcaklýk için 0.1, 0.2, 0.3, 0.4 ve 0.5 m/h olmak üzere beþ ayrý filtrasyon hýzýnda çalýþtýrýlmýþtýr. Filtrelere beslenen dere suyuna az miktarlarda çökelmiþ atýksu karýþtýrýlmýþtýr. Çalýþma sýrasýnda üç ayrý kum yataðýna sahip filtrelerden elde edilen veriler kullanýlarak giriþ suyu kalitesi, arýtma hýzý ve çalýþma sýcaklýklarýnýn filtre çýkýþ suyu kalitesine etkilerini ifade etmek üzere incelenen dört kalite parametresi için 72 regrasyon modeli geliþtirilmiþtir. Kum etkin dane çapý, arýtma hýzý, yatak derinliði, sýcaklýk ve giriþ suyu kalitesinin filtre çýkýþ susyu kalitesine olan etkilerini ifade etmek üzere bir regrasyon modeli geliþtirilmek istenmiþse de verilerde görülen süreksizlik buna imkan vermemiþtir. Ancak geliþtirilen regrasyon modellerinden 9 tanesi yavaþ kum filtrelerinin tasarýmýnda kullanýlabilir. Ýncelenen kalite parametrelerinin hepsindede bütün sýcaklýk ve hýzlarda etkin bir iyileþme görülmüþtür ancak 5 o C deki yüksek arýtma hýzlarýnda indikatör organizma giderimi relatif olarak düþmüþtür. Etkin kum dane çapýnýn filtre çýkýþ suyu kalitesine önemli bir etkisinin olmadýðý gözlenmiþtir. Yeni baþlatýlan yavaþ kum filtrelerinin olgunlaþmasýnýn bir hafta içerisinde tamamlandýðý gözlenmiþtir.

The aim of this research was to obtain a regression model that relates the design and operational parameters and inflow water quality for slow sand filters. Therefore, three laboratory scale slow sand filters with sands of different effective diameters were operated at three different temperatures and at five flow rates. Stream water was used as inflow. Small quantities of settled sewage were added to the feed water. From the data produced, 72 regression models were developed relating inflow water quality and treatment rate to effluent quality for each of four quality parameters, three sand sizes and three temperatures. Attempts to create more complex models linking sand size, treatment rate, bed depth, temperature, inflow quality and filtrate quality were not possible due to the discontinuities in the data. Nine of these simple models can be readily employed in the design of slow sand filters. Effective removal of all four quality parameters was achieved with all flow rates at 25 o C and 15 o C but a definite reduction in the removal of indicator organisms was recorded with the higher flow rates at 5 o C. No significant variation in effluent quality with sand size was recorded. Maturation of the new filters was apparently complete within a week.

Hastahanelerde oluþan týbbi atýklarýn bertaraf edilmesinde, oluþan atýk miktarýnýn ve kaynaðýnýn bilinmesi ve buna göre bertaraf metodunun seçilmesi gereklidir. Bu çalýþmada, Ýstanbul'da faaliyet gösteren bir dispanser ve özel bir hastane'de oluþan týbbi atýklarýn türleri ve miktarlarý araþtýrýlmýþtýr.

In the disposal of medical wastes, it is important to know about the amount and source of wastes occured for the selection of convenient technologies of disposal. In this research, the kinds and amounts of medical wastes occured in a dispensary and a private hospital in istanbul have been searched.