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Gölgeleme araçlarının mekânın toplam soğutma yükleri açısından etkinliklerinin belirlenmesi
Get PDFDuring most hot period it is possible to obtain passive cooling by decrease of surface temperatures with airflow velocities caused by wind, entering interior with the effect of pressure difference through the openings during the time intervals when the outside air is cooler than interior. This effect turns inversed when the outside air temperature is more than interiors. Shading devices used to protect from unwanted solar radiation acting on interior surfaces change the airflow effects acting interiors according to their types. The changes in volume flow rates, interior velocities and solar radiation amount can be advantageous or disadvantageous for total cooling loads according to the time interval as the interior and outside temperatures changes through the day. Determination of the combined effect of shading device efficiency through solar radiation protection strategy and natural ventilation, will give opportunity of designing optimum shading device. In validation of shading device efficiency with different types of shading device alternatives, zone gains and losses with convection, zone sensible gain and losses with ventilation, zone gains from windows and total cooling loads through specific time intervals are compared. Cooling load calculations are run through energy analysis simulation program Energyplus using heat balance calculation method. Convection coefficients, exhibiting the effects of the interior velocities which change by shading devices are calculated by using the datas of velocity measurements performed on wind tunnel with a model with 4 different types of shading device and without shading device. Heat gain from opaque interior surfaces by the effect of solar radiation are considered in Energyplus with the output of heat gain to air by convection. As opening dimensions are directly related to volume flow rates, required in calculation of sensible heat gains of zone by ventilation, it is expressed by discharge coefficients obtained by measured velocities on wind tunnel in front of the model and pressure differences between front and back openings for all alternatives. Shaded and unshaded areas occuring by solar radiation acting on facade with different shading device alternatives are considered. All these parameters of shading devices are used in Energyplus cooling load calculation process. For every alternatives 4 simulations of cooling load calculations had been done for open window and closed window in order to emerge the effects of airflows and solar radiation effects through specific times changing by effects of shading devices. The situations with shading device alternatives are classified as follows; Closed window, no shading device, 1SİM3kap.pen; with shading device, parallel to facade with 90ο slat angle parallel to ground, 2.1SİM5kap.pen; parallel to facade with 45ο slat angle parallel to ground, 2.2SİM9kap.pen; perpendicular to facade with 90ο slat angle parallel to facade, 3.1SİM12kap.pen; perpendicular to facade with 45ο slat angle parallel to facade, 3.2SİM15kap.pen, Open window, with no shading device, 1SİM3ac.pen; with shading device, parallel to facade with 90ο slat angle parallel to ground, 2.1SİM5ac.pen; parallel to facade with 45ο slat angle parallel to ground, 2.2SİM9ac.pen; perpendicular to facade with 90ο slat angle parallel to facade, 3.1SİM12ac.pen; perpendicular to facade with 45ο slat angle parallel to facade, 3.2SİM15ac.pen, The effects of shading devices on total cooling loads and 3 gain components are evaluated through the time intervals of 01:00-07:00, 08:00-18:00, 19:00-24:00 during the day. 4 simulations of cooling load are made for the situation with no shading device and shading device. In the 1. simulation run for closed window (1SİM3kap.pen, 2.1SİM5 kap.pen, 2.2SİM9kap.pen, 3.1SİM12 kap.pen, 3.2SİM15kap.pen) and 2. Simulation for open window (1SİM3ac.pen, 2.1SİM5ac.pen, 2.2SİM9 ac.pen, 3.1SİM12ac.pen,3.2SİM15ac.pen); Zone’s hourly gain by convection from interior surfaces, Zone’s hourly gain and loss by ventilation; Zone’s hourly gain and loss from window; Zone’s total cooling load, are obtained.3 and 4. simulations of cooling load are made for the situation without shading device and with shading device for open and closed window in order to get interior mean air and surface temperatures. The average results of total cooling load, infiltration sensible gain, convection to air rate, window heat gain through these hours are compared with no shading device situation by summing the results through 01:00-07:00, 08:00-18:00, 19:00-24:00time intervals. Keywords: Shading device, natural ventilation, total cooling load.Isıtmaya gereksinim duyulmayan dönemlerde (ESD) güneşin istenmeyen ısıl etkilerinden korunmak üzere gölgeleme araçları kullanılmaktadır. Dış hava sıcaklığının iç hava sıcaklığından az olduğu saatlerde, açıklıklardan rüzgâr basıncı ile içeri giren hava akımlarının etkisi ile yüzeyden ısı taşınımıyla soğutma sağlamak mümkündür. Bu etki dış hava sıcaklığının iç hava sıcaklığından yüksek olduğu saatlerde tersine dönmektedir. Güneşin açılarına göre farklı tipte tasarlanan gölgeleme araçlarının hem doğal havalandırma hem de güneş korunumuna bağlı bileşik etkinliğinin değerlendirilmesi ile optimum gölgeleme aracı tasarlamak mümkün olacaktır. Gölgeleme araçlarının gün içerisinde farklı zaman aralıklarında etkinliğinin değerlendirilmesinde; farklı tipte gölgeleme aracı takılı durumda, ortamın yüzeylerden taşınım yolu ile kazanım, havalandırma yolu ile hissedilen kazanım, pencerelerden kazanım bileşenlerinin ve mekânda oluşan toplam soğutma yüklerinin gün içerisinde belirli zaman aralıklarındaki ortalamaları karşılaştırılmıştır. Soğutma yükü hesapları ısı dengesi hesap yöntemini kullanan Energyplus programında yürütülmüştür. Ortamın yüzeylerden taşınım yolu ile kazanımlarının hesaplanmasında gölgeleme araçları ile değişen iç hava hareketi hızlarının etkisini ortaya koyan ortalama taşınım katsayıları rüzgâr tünelinde gölgeleme araçsız ve 4 farklı tipte gölgeleme aracı takılı durum için bina modeli içinde gerçekleştirilen hız ölçüm bulguları ile hesaplanmıştır. Güneş yolu ile iç opak yüzeylerin ısı kazanımları da bu bileşen içinde göz önüne alınmıştır. Ortamın havalandırma yolu ile hissedilen kazanımlarının hesaplanmasında gereken hacimsel debi miktarları gölgeleme araçları takılı durumda model ön ve arka yüzeyinde ölçülen basınçlar, hızlar, boşaltım katsayıları ve gölgeleme araç tiplerine göre değişim gösteren açıklık alanları ile bulunmuştur. Pencereden kazanımlarda dış yüzeyde oluşan gölgeli ve gölgesiz alanlar göz önüne alınmıştır.Anahtar Kelimeler: Gölgeleme araçları, doğal havalandırma, soğutma yükü
Bir mimara ait konut tasarımlarının mekan sentaksı yöntemiyle analizi
Get PDFThe observable formal characteristics of the buildings constitute the center of popular architectural evaluations. On the other hand, the main discipline in architecture is ‘space’. One of the methods developed to define and analyze the abstract characteristics of spatial configuration is Space Syntax. This method can be defined as the collection of techniques and theories developed to explore the spatial structures of the man-made environment. The main goal is to represent, discuss, and interpret the intuitively perceived space on concrete terms. By the means of syntactic data obtained, it is argued that significant information about the formation process of the spatial layout and the social meanings underlying this structure can be reached. In this research, 42 single-family houses designed by Yılmaz Sanlı, in the period 1960-2004 are analyzed. They are collected in three different samples arranged according to the dates they are designed. In this study the answers to three main questions are searched: Is it possible to talk about common abstract rules underlying the spatial layouts in three samples, in other words, genotypes? If these rules are discovered, what can be said about the similarities and differences among the genotypes? What kind of variations come up depending on the changes in the house type, geography, user characteristics, and formal compositions? Is it possible to extract concrete data on the spatial layouts of the housing projects of a single architect by the means of the analytical techniques of space syntax? In this context how can the findings contribute to Turkish architecture? In the first step, a house-by-house study is realized. It starts with the short description of the house. Then the justified graphs, both with and without the exterior, are created. Next the syntactic analysis is constituted on the graphs. Following the house-by-house analysis, by the evaluations and interpretations of the collected data, the genotype is identified with all the common rules detected in the sample. The stated steps are repeated for three samples. Finally, the similarities and differences among the genotypes in the architect’s designs are discussed. The first sample (1960-1985) indicates that the architect is influenced by modernism. His designs are composed of pure geometric forms and minimalist layouts. In this sample there are user-defined and user-undefined projects. The majority of these examples are secondary houses used only during the summer or on the weekends. Only 3 of them are primary houses used throughout the year. The projects designed with respect to the demands of a specific client demonstrate configurational differences. Another aspect detected in the analysis is that, the city houses outstand from the others with their deep integration cores as a reflection of their traditional plan organization. The other modernist designs, however, have shallow integration cores. The second sample includes 15 houses from the period 1985-1995. In these years, there is an obvious breaking away from modernism and designs reflect traditional and vernacular details both in the interior and on the exterior. 3 examples are luxurious city houses with a character reminding Sedat Hakki Eldem Housing. 5 houses are suburban villas used all year, 4 houses are weekend houses and 3 houses are summer houses in the south of Turkey. The justified graphs of this sample are much more complex than the first sample. They are less affected by the exclusion of the exterior and the graphs differ with respect to the number of vertical circulation. The configuration is structured according to the use of stairs in the design. The integration core is much deeper than the first sample. The last period is a reflection of “pluralism” in Yılmaz Sanlı architecture. 6 houses are summer houses designed in the south of Turkey and 9 houses are examples of commutable housing in the suburbs of Istanbul. The spatial configuration is primarily structured according to the design of the upper floor; whether it is partially-used or completely-used. The integration core is shallow when the upper floor is partially used and deeper when it is completely used. In this study by the means of exploration of the configurational characteristics, the information underlying the house designs is reached. By the findings of the research a comprehensive range of knowledge content is constituted on a valuable architect’s housing designs. It is believed that similar studies will provide a rich database for the architects to apply in their own design processes. Keywords: Space, space syntax, spatial analysis, housing design.Mimar mekanı, mekanlar bütününü ve bu bütün içinde süregelen insan yaşamını biçimlendirir. Bir anlamda mekan insanı çevreleyen fiziksel bir kabuktan ötedir; içinde var olan yaşama, alışkanlıklara, ilişkilere temellenen çok boyutlu, çok katmanlı bilgileri içerir. Mekanın bu karmaşık yapısı içinde var olan bilginin çözümlenmesi, ortaya konması ve tartışma ortamına taşınmasında problemleri de beraberinde getirmektedir. Mekan Sentaksı yerleşim ve yapı ölçeğinde, inşa edilmiş çevrenin mekansal dokusunu incelemek için geliştirilmiş teknikler ve teoriler bütünü olarak tanımlanabilir. Bu çalışmada ilk adımda mekan kurgusunu sorgulayabilmek ve tartışmaya açabilmek için başvurulan metotlardan biri olan mekan sentaksı üzerinde durulmaktadır. İkinci adımda ise mekan sentaksı kullanılarak Türkiye Mimarlığı’nın öncü temsilcilerinden Yılmaz Sanlı’nın 40 yılı aşkın bir süre içinde gerçekleştirdiği konut tasarımları üzerinde kapsamlı bir konfigürasyonel analiz gerçekleştirilmektedir. 42 konut örneği kronolojik sıralamaya göre üç dönem altında toplanır. Gerçekleştirilecek olan analizde 3 soruya yanıt aranmaktadır: 1. Farklı dönemlerde gerçekleştirilmiş Yılmaz Sanlı tek aile evlerine ilişkin mekansal modellerde, paylaşılan, kendine özgü kurallar dizisinden ve/veya eğilimlerden (genotiplerden) söz edilebilir mi? 2. Eğer var ise, bu genotipler arasında ne tür benzerlikler ve farklılıklar söz konusudur? 3. Mekan sentaksı teknikleri ile bir mimarın konut tasarımları özelinde, mekana ilişkin sezgisel yaklaşımla yapılabilen yorumlara karşılık, daha nesnel ve analitik bir tutum ile somut tanımlamalara ulaşılabilir mi? Bu çalışmada elde edilen bulguların Yılmaz Sanlı mimarlığı üzerinde konuşmak üzere zengin bir bilgi birikimi oluşturduğu ve araştırma ve uygulama, bilim ve tasarım ilişkisini dillendirecek deneysel bir yaklaşım ortaya koyduğu düşünülür. Anahtar Kelimeler: Mekan, mekansal analiz, mekan sentaksı, konut tasarımı
Polietilen destekli AA 7075 T651 levhalarda katman sıralamasının balistik dayanıma etkisi
Get PDFUsing armor systems in battle field is a necessity. These protection tools have been gaining more importance day by day since the wars in the ancient times. Human beings throughout recorded history have used various types of materials to protect themselves from injury in combat and other dangerous situations. At first, protective clothing and shields were made from animal skins. As technology became more advanced, wooden shields and then metal shields came into use. Armor systems, particularly those used for the military purpose must be designed as protection against modern weapons. For this reason, ballistic efficiency of the armor subjected to impact load of specific ammunition is under investigation. Armors designed by using together the ballistic specifications of metal and composite materials used in armor applications provide the desired protection level regarding the weight and ballistic efficiency. Layered structures are generally used in ballistic armor systems. Layered armors basically consist of two main parts: front layer and support layer. Front layers are made from metal or ceramic materials. They aim to deform the nose shape of the projectile and to reduce its ballistic efficiency. Rear or support layers are assigned to absorb the remaining kinetic energy of the projectile. Metal, composite and/or elastomer materials are used in integral armor systems as a support layer. Armor steels, titanium and aluminum alloy materials are most commonly used armor materials. Hardness values of these materials can be at extremely high levels. Aluminum alloys find their use in many different structures such as offshore platforms, bridge decks, train and ship components, etc. Due to their low density, high structural strength and energy absorption capacity, aluminum alloys are also used in lightweight protection systems. Composites have been commonly used in lightweight armor systems. In addition to various advantages, composites are also preferred due to their high energy absorption capacity. At this point, it must be taken into account that quite a high ballistic performance can be acquired in composite armor structures established by using ultra high molecular weight polyethylene fibers. In many studies, it is found that polyethylene has an ultra high energy absorption capacity as well as its low density. In this study, influence of layer sequencing was investigated experimentally on ballistic resistance of aluminum plates supported by using high molecular weight polyethylene plates. In experiments, 7075 aluminum alloys of T651 heat treatment were used. Three different types of layer sequencing were examined in the study. It was aimed in the choice of the aluminum alloys used in the tests that effects of the support layer on the ballistic performance of the plates must be investigated distinctively. Focusing on this aim, it was decided that using the aluminum alloys whose ballistic performance is well known without support layer is more convenient. It is known from the previous tests that AA 7075 T651 aluminum plates of 4.00 mm thickness are perforated at 383~400 m/s projectile velocity interval and without the support layer. Using this knowledge, influence of three different types of layer sequencing on ballistic performance of the AA 7075 T651 aluminum plates of 4.00 mm thickness with polyethylene support layer was investigated. In experiments, MKEK (Mechanical and Chemical Industry Corporation) made FMJ (Full Metal Jacket) Parabellum bullets of 9 mm diameter and 19 mm length were used. The distance between the target plate holder and the shooting system is 5 meters. All shots were normal to target plates. Oehler Research optical ballistic devices were used for the velocity measurements. To test the one plate of 250x250 mm dimensions for four times by separating the plate, a multi shooting fixture was designed, fabricated and used. It was also used to represent the fully clamped boundary conditions. Plate was placed between the two parts of the fixture and bolted at the middle points of four edges. As a result of the experiments, despite the fact that three of the layer sequencings have the same thickness, it was clearly observed that the best ballistic performance can be obtained by sequencing the aluminum plate as a front layer and the polyethylene support layer at the rear side. Otherwise, it was clearly understood from the test results that plate thicknesses influence the deformation mechanisms due to high velocity impact. Keywords: Ballistic resistance, layered armor, layer sequencing, high velocity impact.Bu çalışmada, yüksek molekül ağırlıklı polietilen levhalar kullanılarak desteklenmiş AA 7075 T651 levhaların balistik dayanımlarına üç farklı katman sıralamasının etkileri deneysel olarak incelenmiştir. Alüminyum alaşımlar, düşük yoğunluk, yüksek yapısal mukavemet ve enerji emiş kapasitesi özellikleri açılarından, yapısal uygulamalar yanında, hafif korunma sistemlerinde de kullanılmaktadır. 4.00 mm kalınlığındaki AA 7075 T651 levhaların, destek katmanı olmadan belirli mermi hızlarında delindikleri yapılan ön testlerde belirlenmiştir. Bu bilgi kullanılarak, farklı katman sıralamalarının balistik dayanıma etkileri deneysel olarak incelenmiştir. İncelenen ilk grupta, ön katman olarak 8.00 mm kalınlığında polietilen ve destek katmanı olarak 4.00 mm kalınlığında AA 7075 T651 levha, ikinci grupta 2.00 mm kalınlığında iki AA 7075 T651 levha arasında 8.00 mm kalınlığında polietilen levha, son grupta ise ön katman olarak 4.00 mm kalınlığında AA 7075 T651 ve destek katmanı olarak 8.00 mm kalınlığında polietilen levha kullanılmıştır. 2’nci HİBM Komutanlığı bünyesinde bulunan atış poligonunda gerçekleştiren deneylerde, MKEK yapımı 9 mm çapında Parabellum mermiler kullanılmıştır. Tüm atışlar 5 m uzaklıktan ve levhaya dik olarak gerçekleştirilmiştir. Yapılan deneyler sonucunda, her üç tasarımın da toplam katman kalınlıkları eşit olduğu halde, destek katmanı olarak kullanılan polietilen levhaların, alüminyum levhaların arkalarına yerleştirildikleri seçeneğin, en yüksek balistik dayanıma sahip tasarım olduğu belirlenmiştir. Deneylerde ayrıca, levha kalınlıklarının, yüksek hızlı çarpma sonucunda oluşan hasar biçimlerini yakından etkilediği gözlenmiştir. Anahtar Kelimeler: Balistik dayanım, katmanlı zırh, katman sıralaması, yüksek hızlı çarpma. 
Havalandırmanın çoklu-split bir iklimlendirme sisteminin performansına etkisi
Get PDFAir conditioning and ventilation for residential and commercial buildings are highly demanded due to concerns on thermal comfort and healthy environment of the living space in modern society. Multi-split air conditioning system, featuring variable refrigerant flow technology, so-called multi-split variable refrigerant flow system is finding its way in residential and commercial buildings. The multi-split variable refrigerant flow systems have one outdoor which is connected to several indoor units with different configurations and capacities. The outdoor unit consists of two or three compressors, one of which is variable speed compressor driven by an inverter frequency drive. The precise capacity control is provided by this inverter driven compressor and individual electronic expansion valves located in each indoor unit. Depending on the indoor cooling and heating loads, the required refrigerant mass flow rate is provided by varying the inverter frequency of the variable speed compressor, and electronic expansion valves are operated in such a way to keep the indoor temperature at the indoor thermostat set temperature. The first multi-split variable refrigerant flow system was installed more than 20 years ago in Asia. Due to the long history of this technology, the multi-split variable refrigerant flow systems have been widely studied experimentally and numerically. Previous studies mostly focused on control strategies of the variable speed compressor, and electronic expansion valves of multi-split systems. It was observed that the frequency of the compressor and the electronic expansion valve openings of the indoor units should be controlled simultaneous. On the contrary, it was also claimed that the major control parameter was the electronic expansion valve opening. In addition to studies related to the control strategy, the performance of the multi-split type systems has been investigated. One of the main drawbacks of these multi-split variable refrigerant flow systems is that they can not provide any ventilation to the indoors which is required by the American Society of Heating, Refrigeration and Air conditioning Engineers (ASHRAE) regulations. The multi-split variable refrigerant systems condition the indoor air by circulating it through their indoor units without adding any fresh air. That's why; additional ventilation systems should be installed to the buildings. Thus; integration of the multi-split variable refrigerant flow system and the ventilation system gains importance in actual applications. Despite large number of previous studies, there is not an actual operational study under varying outdoor conditions which considered the effect of the ventilation on the performance of the multi-split variable refrigerant flow system. In this study, a field performance evaluation of a multi-split variable refrigerant flow system integrated with a heat recovery ventilation system is investigated experimentally under varying outdoor conditions in the cooling season. The effect of the ventilation on the performance (indoor temperature control, outdoor unit energy consumption, efficiency) of the multi-split variable refrigerant flow system is investigated. Two multi-split variable refrigerant flow systems and four heat recovery ventilation units were installed in an actual office suite for the field performance tests. The multi-split variable refrigerant flow systems were operated either stand-alone or in conjunction with heat recovery ventilation units during the experiments. Both systems, as well as indoor and outdoor environments were fully instrumented for measurement and comparison purposes. Parametric tests were performed in the cooling seasons of 2006 and 2007. It was found from the experimental evaluation that for both cases; ventilation assisted and non-ventilated multi-split variable refrigerant flow systems, they could maintain the set temperature of 25°C. It was also observed that heat recovery ventilation units increased the indoor humidity ratio by around 0.002 kg/kg during the ventilation, and according to the ASHRAE summer comfort zone, the ventilation assisted multi-split variable refrigerant flow system provided relatively uncomfortable indoor environment compared to the non-ventilated case. It was also obtained that, as expected due to the additional ventilation cooling load, the ventilation assisted multi-split variable refrigerant flow system consumed around 18% higher energy compared to the non-ventilated multi-split variable refrigerant flow system. It was found that the ventilation system did not affect the efficiency of the multi-split variable refrigerant flow. Overall, it was concluded that even though the ventilation system did not affect the indoor temperature control and the efficiency of the multi-split variable refrigerant flow system, it did affect the indoor thermal comfort and energy consumption of the outdoor units. Keywords: Multi-split, variable refrigerant flow, air conditioning, ventilation. Hem evsel, hem de ticari binalarda konforlu ve sağlıklı bir yaşam alanı oluşturmak için, iklimlendirme ve havalandırma sistemleri sıklıkla istenmekte ve uygulanmaktadır. Çoklu-split Değişken Soğutkan Akışlı (DSA) sistem olarak da bilinen bir dış ve birden fazla iç üniteden oluşan çoklu-split iklimlendirme sistemleri hem evsel, hem de ticari binalarda kendine yer bulmaya başlamıştır. Bu tip sistemlerde dış ünite içinde, içlerinden biri değişken hızlı kompresör olmak üzere iki ya da üç kompresör bulunmaktadır. Genel olarak, iç ortam soğutma ve ısıtma yüklerine bağlı olarak azalan ve artan sistem soğutkan kütlesel debi ihtiyacı, değişken hızlı kompresörün frekansı değiştirilerek sağlanmaktadır. Böylece hassas sistem kapasite ayarı yapılabilmektedir. Değişken hızlı kompresöre ek olarak, her iç ünitede bir Elektronik Kısılma Vanası (EKV) bulunmaktadır. Bu EKV'ler sayesinde, her iç üniteden geçen soğutkan kütlesel debisi, termostat sıcaklığını sağlayacak şekilde ayarlanabilmektedir. Çoklu-split DSA sistemleri iklimlendirme yapabilmesine rağmen, iç ortama, yönetmeliklerde belirlenen hususlar çerçevesinde taze hava sağlayamamaktadırlar. Bu nedenden dolayı da, binalara çoklu-split DSA sistemi ile beraber, havalandırma sistemleri de takılması gerekmektedir. Böylece, çoklu-split DSA sistemleri ile havalandırma sistemlerinin birleştirilmesi, gerçek uygulamalarda önem kazanmaktadır. Bu çalışmada, ısı geri kazanım havalandırma sistemi ile birleştirilmiş bir çoklu-split DSA sisteminin soğutma sezonundaki saha, değişken dış hava koşulları altında deneysel olarak incelenmiş ve havalandırmanın çoklu-split DSA sisteminin performansına (iç ortam sıcaklık kontrolü, dış ünite enerji tüketimi, sistem verimi) etkisi araştırılmıştır. Anahtar Kelimeler: Çoklu-split, değişken soğutkan akış, iklimlendirme, havalandırma. 
Selection of R&D projects with real options integrated fuzzy multi-criteria model
Get PDFAraştırma ve geliştirme; yeni bilgiler elde etmek ya da mevcut bilgileri ortaya çıkarmak amacıyla yapılan ve bilginin sistematik olarak toplanmasını, analizini ve yorumunu gerektiren bir çalışmadır. Ar-Ge'nin başlıca görevi teknolojik gelişmeleri kullanarak işletmenin devamlı yenilenmesini sağlama ve bu sayede kârın sürekliliğini sağlamak hatta artırmaktır. Yenilikçi fikir, değişim ve gelişim, yepyeni teknolojiye sahip olmak rekabette üretim verimi, fiyat, reklam ve pazarlama kadar önemlidir. Araştırma-geliştirme projeleri seçimi, gelişmekte olan ülkelerdeki işletmelerde gerek kaynak, gerekse zaman kısıtları açısından gelişmiş ülkelere göre daha önemlidir. Doğru ve şirket içinde sinerji yaratacak projelerin seçimi kaynakların verimli şekilde kullanılmasını sağlayacaktır. Ar-Ge projelerinin doğası gereği kurumsal getirileri çok boyutludur ve kazançları risklidir. Bu çalışma, Ar-Ge proje seçim sürecinin çok boyutlu tarafını incelemektedir. Ar-Ge proje seçenekleri arasından seçim, parasal (bulanık gerçek opsiyon değeri) ve parasal olmayan (kapasite, başarı olasılığı, eğilimler vb.) ölçütleri birlikte dikkate alan Bulanık Analitik Hiyerarşi Prosesi (AHP) yardımıyla yapılacaktır. Gerçek opsiyon yaklaşımı seçim sürecinin riskli tarafını hesaplamaya yardımcı olur. Gerçek opsiyon, akit fiyatı olarak adlandırılan önceden belirlenmiş maliyette, opsiyonun süresi olarak adlandırılan önceden belirlenmiş bir zaman diliminde, bir eylem (erteleme, genişletme, küçültme ya da bırakma) için harekete geçme hakkıdır; zorunluluk içermez. Değerleme sürecindeki bir diğer ele alınması gereken konu ise belirsizliktir. Literatürde, yeterli bilginin olmadığı durumlara yönelik bulanık gerçek opsiyon değerleme modelleri geliştirilmiştir. Önerilen yaklaşımı daha iyi gösterebilmek amacıyla yapılan gerçek bir çalışma da uygulama bölümünde anlatılmaktadır. Anahtar Kelimeler: Ar-Ge projeleri, gerçek opsiyonlar, bulanık AHP, çok ölçütlü seçim. Research and development; is a term of activity that a foundation develops new products, processes or services by the way of employing scientists and engineers in accordance with the foundation's workplace. In other words, R&D is a work that is made to reach new information or discover the existing know-how by gathering the data systematically, analyze and make comment on these data. The essential duty of R&D is to use the technological developing for carrying on and if possible augmenting the ability of the company's profitability. In the competition process, innovation, evolution, development, and having brand new technology are as important as production efficiency, price, and advertisement and marketing. Phases of R&D projects could be defined: Phase Zero: Finding and eliminating raw ideas, at this beginning phase new commercially hopeful ideas are produced. These ideas are selected and transformed to suitable, consistent development projects. Phase One: Conceptual Research, in that phase, constraints and contents of raw ideas are understood. How to produce the ideas in hand from laboratory conditions to practice are made in that phase. Phase Two: Feasibility, the subject of this phase is to solve known problems and produce the cost and performance data for engineers and salesperson to undertake the research. Phase Three: Development, at the development phase, required technical properties, specifications, and production processes are determined to be able to produce the product. Phase Four: Early Commercialize, in general early commercialize is very dangerous and risky transition phase for financial supporters. The dissatisfaction related with this phase is determinant and highly anticipated. If the problems and troubles could not be defined well, though the market says contrary, presentation of the product should be postponed. While the valuation methods of R&D projects are evolved from basic to hard, they conducted a long process. At that required process the valuation methods are: Classical Methods, Portfolio methods, Organizational decision making methods, and Multi-criteria evaluation methods. Real options are based on financial options. An option gives the holder the right to buy or sell the underlying asset by a certain date for a certain price but contains no obligation. A real option is a right to act an action (defer, expand, contract or abandon) in the predetermined cost called strike price and in the predetermined period called expiration time, beside does not contain an obligation. In this dissertation, Black-Scholes pricing method investigated under fuzziness will be utilized. In literature, fuzzy real option valuation models are developed to the lack of exact data situations. At first, a heuristic real option valuation process is developed for fuzzy state. At that process, present values of expected costs and expected cash flows are denoted with trapezoidal fuzzy numbers. The most suitable time for the exercise date of the option is determined by the help of possibilistic mean value and variance. In another study, fuzzy zero-one integer programming and fuzzy real option valuation are used in the selection of R&D portfolio. In these studies, policies that can be support for decision are considered in the selection of best R&D project process in a corporate. The mostly used method AHP is capable of handling multiple objectives for R&D projects and decomposing the problem into multilevel structure or hierarchy. Its data requirement is minimal and both qualitative and quantitative data can be considered and compared simultaneously in the model. Real circumstances in daily life are very often uncertain and vague in several ways. When there is a lack of information, a system might not be known completely. So, fuzzy AHP is required in these circumstances. Fuzzy real option valuation model and fuzzy AHP methods are integrated in this work. Qulitative and quantitative sides of the method are met together. The integrated method mentioned above is applied in a corporation owns respectable place in electronic industry in Turkey. Six R&D projects of this company are evaluated by using the concerned methods and the first one in the order is selected. Selection made by that method is shared with the company, however because of the breaking crisis the option to delay has to be used. Keywords: R&D projects, Real options, fuzzy AHP, multi-criteria selection
Investigation of silicalite-1 synthesis mechanism from nanoparticles
Get PDFSilikalit-1 sentez karışımlarında başlangıçta oluşan nanotaneciklerin çekirdeklenme ve kristal büyümesi süreçlerindeki rolleri bilinmemektedir. Bu çalışmada, sentez sırasında meydana gelen olayların ayrıntılı olarak izlenmesi yoluyla çekirdeklenme ve tanecik büyümesi süreçlerinin aydınlatılması için 9TPAOH-480H2O-25SiO2 bileşimi ile hazırlanan sentez çözeltisi kullanılarak, 100°C’de deneyler yapılmıştır. Ortalama tanecik boyutlarının zamanla değişimlerinin izlenmesi için dinamik ışık saçılımı (DLS) yönteminden, faz analizleri için x-ışını kırınımından (XRD), fonksiyonel grupların belirlenmesi için de Fourier Transform Infrared spektroskopisinden (FTIR) yararlanılmıştır. TPA+ katyonunun örneklerin yapılarındaki yerinin belirlenmesi için termal gravimetrik analiz (TGA) uygulanmıştır. Azot adsorpsiyonu ile örneklerin mikrogözenek hacimleri ve gözenek boyutu dağılımları belirlenmiş, atomik kuvvet mikroskobu (AFM) ile son ürünün boyutu ve morfolojisi görüntülenmiştir. Sentezin başında çözeltide bulunduğu belirlenen, ortalama boyutları 2 nm olan taneciklerin, sıcaklığın artırılmasıyla kısa bir süre içinde, yerlerini ortalama boyu 20 nm olan taneciklerden oluşan ikinci bir popülasyona bıraktığı görülmüştür. Bu popülasyonun ortalama tane boyutunun belirli bir süre boyunca sabit kaldığı, ancak bu süre içinde tanelerin bileşimleri ve yapılarının değiştiği belirlenmiştir. Daha sonra ortalama boyutlar gerçekleşen aglomerasyon sonucunda aniden artmış ve ortaya lineer olarak büyümeye başlayan üçüncü bir tane popülasyonu çıkmıştır. XRD ve TGA sonuçları kristalinitenin ilk belirtilerinin bu noktada oluştuğunu göstermiştir. Büyüme mekanizması olarak tanecik eklenmesinin geçerli olduğu görülmüş, tüm analizler bu sonucu doğrulamıştır. Anahtar Kelimeler: Silikalit–1 sentezi, nanotaneler, çekirdeklenme ve büyüme mekanizmaları.Zeolites are crystalline microporous aluminosilicates. They have gained importance in catalysis, adsorption and ion-exchange applications due to their pores and channels of molecular dimensions. The achievement of the synthesis of colloidal zeolites with increased external surface areas and shortened diffusion paths, made the use of these materials in new emerging fields such as microelectronics, biochemistry and membrane separations possible and attractive. The possibilities of synthesizing zeolites from clear solutions instead of heterogeneous mixtures containing gel phases, and the applicability of light scattering techniques to these solutions have allowed the monitoring of nucleation and particle growth during synthesis, which has been an impetus for the studies in this field. Silicalite-1 has been the first zeolite synthesized with colloidal dimensions from clear solutions. The roles of nanoparticles, formed at the very beginning in silicalite-1 synthesis mixtures, in nucleation and crystal growth processes are not well-known. The purpose of this study was to investigate the nucleation and crystal growth mechanisms of silicalite-1 and to shed light on the roles of the nanoparticles during crystallization. Experiments were performed at 100 °C using a reaction mixture with the composition of 9TPAOH-480H2O-25SiO2. Dynamic light scattering technique (DLS) was used to observe the variation of average particle size with time, X-ray diffraction (XRD) and fourier transform infrared spectroscopy (FTIR) were used for phase identification. Thermal gravimetric (TG) analyses were performed to determine the position of the TPA+ cation in the structures of the samples. The micropore volume and the pore size distribution of the samples were determined by nitrogen adsorption while the size and morphology of the final product were imaged by atomic force microscopy (AFM). Additionally, the alkalinity of the solution and the surface charges of the particles, which may be helpful in explaining the mechanism, were monitored by pH and zeta potential measurements. It was observed that the particles present in the solution at the beginning of the synthesis, having an average size of 2 nm, were replaced by a second population consisting of particles with an average size of 20 nm, shortly after the temperature was increased. The average particle size of this population remained constant for some period, while the compositions and structures of the particles were observed to change according to the TG analyses. Afterwards, a sudden increase was observed in the particle size, due to agglomeration, giving rise to a third population growing at a constant rate. XRD, FTIR and TG analyses showed that the first indications of crystallinity appeared at this point. This results indicate that the evolution of crystallinity started right at the point of sudden increase in particle size. Before the sudden increase in particle size, the samples were basically mesoporous in nature but also contained micropores to some extent, according to the nitrogen adsorption isotherms. In parallel to the crystallinity increase, starting with the growth of the particles, the zeolitic micropore volume increased while the mesopores decreased. The variations in pH and zeta potential values were very informative about the course of crystallization. pH values increased parallel to the increase in the crystallinity of the growing particles (third population) and then remained constant. Two sudden drops were observed in the zeta potential of the particles. The first one occurred when particle size increased suddenly and the second one took place when the particle growth stopped. The first sudden decrease in zeta potential when the particle size exhibited a sudden increase was the indication of the increase in negative surface charge, due to loss in surface area as a result of the sudden agglomeration that took place at that stage in the course of crystallization. AFM analyses applied to the final product indicated that the growth process took place mainly by particle addition to the growing crystals. Size growth stopped when the solution was depleted of the growth units, probably as a result of the decrease in silica concentration and increase in the pH of the solution. The continuing increase in the crystallinity of the particles after size growth stopped implied that monomer addition from solution also took place. Keywords: Silicalite-1 synthesis, nanoparticles, nucleation and growth mechanisms
Dilli örme iğnelerindeki aşınmaların SEM stereoskopi yöntemiyle incelenmesi
Get PDFIn this study, the wear occurred inside the latch needle hook was examined empirically to be able to explain how they were affected by the type of yarns. The wear of the needle hooks was represented numerically. Scanning electron microscope stereoscopy (SEM), which is a method of characterizing the surface topography by the application of computer image analysis to SEM images (stereoscopic pairs), was used for the evaluation of the needle surfaces. The average surface roughness parameter (Ra) was utilized for investigating the wear inside the needle hooks. To aid the investigation of the wear inside the latch needle hooks which caused by the yarn contact during the knitting production, a set of controlled test production was carried out. Mayer & Cie. with 14 systems, 14 Fayn-20 Gauge interlock knitting machine (2*876 needles) was employed for the fabric production. The production was realized under the commercial production conditions in terms of relative humidity and temperature. In order to examine the wear states of the needle hooks four different yarn types (100% cotton ring, 100% cotton OE-rotor, 100% viscose ring and 100% polyester ring) were chosen for the test productions. The knitting period for each production was determined to be five days (120 hours). The machine parameters, such as machine speed, yarn input tension and fabric takedown tension, were stabilized during all productions. At the end of the each knitting period, the needles taken from the same part of the needle bed were replaced with the new ones before starting to knit with the next yarn type. A challenging problem was the characterization of the surface topography of the worn needle surfaces. Currently available methods, such as laser confocal microscopy, phase shift interferometry and atomic force microscopy exhibit severe limitation regarding their applications to the acquisition of 3-D surface topography data. Therefore SEM stereoscopy was preferred to accurately recreate a 3-D image of the surfaces. Two stereoscopic images were taken by tilting the specimen holder from +6° to -6°. All images which have a resolution of 1024*760 pixels, 256 grey levels were taken with a Zeiss Supra 50VP SEM. For a comparative study regarding the differences in topography of the hook surfaces numerically, stereoscopic SEM images, acquired from the inner parts of the needle hooks were used for the reconstruction surfaces in 3D by means of image analyzing software. SEM images were also displayed in anaglyph mode. By viewing with anaglyph glasses, observer can get 3D impression of the surfaces. In addition to this, the topographic information and the average roughness parameter of the needle surfaces were measured by means of the image analysing software. In order to evaluate the change in topographical texture and surface roughness, the unused needles and the needles knitted with different yarns were compared with their SEM images and also their measured Ra values. For this purpose, two sample t-test was performed between the Ra values of the needles, knitted with four different yarn types, and the unused needle samples. Two sample t-test showed that there were differences between the Ra values, which means that the knitting period (five days) was found to be enough to wear off the surface of the needle hooks. After examining the SEM images and Ra values, the wear of the surface of the needle hooks were affected differently by the yarn types. Finally, the amount of wear formed during the knitting process at the inner surfaces of the latch needle hooks is affected by the type of yarns. After examining the Ra values and SEM images of those surfaces, it can be said that 100% cotton ring yarn and 100 % viscose ring yarn caused similar impact on the needle hook surfaces while 100 % cotton OE-rotor and 100 % polyester yarns showed different effect on the surfaces that means moving yarns on the needle hooks cause some chances on the texture of the surfaces. Furthermore, SEM stereoscopy method used for the reconstruction of the needle surface in 3D and getting the topographical information from those images, was suggested to compare the wear differences between the surfaces of the needles by means of roughness parameters. As a result, SEM stereoscopy could be used to understand the wear mechanism of the surfaces of needles. Keywords: Latch needle, SEM stereoscopy, average surface roughness.Bu çalışmada, SEM stereoskopi görüntüleri ve yüzey pürüzlülük parametreleri kullanılarak, örme bölgesindeki iplik temasından dolayı iğnelerinin kanca kısmında meydana gelen aşınmalar incelenmiştir. İğnelerdeki aşınmaları sayısal olarak gösterebilmek ve belirlenen makine parametresinde, iplik kalitelerine bağlı olarak açıklayabilmek için bir seri kontrollü test üretimi gerçekleştirilmiştir. Hem her iplik kalitesine ait üretimi temsil eden iğneler, hem de kullanılmamış iğne yüzeyleri SEM’de incelenmiştir. İğnelerin kanca iç yüzeyinden alınan stereoskopik SEM görüntüleri, görüntü işleme yazılımı vasıtasıyla üç boyutlu hale getirilmiştir. Oluşturulan üç boyutlu yüzeylerden topografik bilgiler alınarak, yüzey pürüzlülük ölçümleri gerçekleştirilmiştir. İğne yüzeylerinin karşılaştırılmasında, “Ra” ortalama yüzey pürüzlülük parametresi kullanılmıştır. Sonuçlar istatistiksel olarak değerlendirilmiştir. Yapılan t-testi sonucunda kullanılan iğneler ile kullanılmamış iğnelerin yüzeyleri arasında fark olduğu belirlenmiştir. Kullanılan iğnelere ait SEM görüntüleri ve Ra ortalama pürüzlülük değerlerinin bir arada incelenmesi ile aralarındaki ilişki irdelenmiştir. Çalışmanın sonunda, hem üç boyutlu iğne yüzeyinin oluşturulmasında, hem de bu görüntülerden topografik bilginin elde edilmesinde kullanılan ve şimdiye kadar tekstil makinelerine ait malzeme yüzeyi değerlendirmesinde uygulaması görülmemiş olan SEM stereoskopi yöntemi, iğne aşınma davranışını açıklamada kullanılabilir bir yöntem olarak önerilmektedir. Böylece, SEM stereoskopi yöntemiyle elde edilen Ra ölçümlerinin mikron boyutlardaki aşınmaların değerlendirmesinde kullanılabilecek alternatif bir yöntem olduğu gösterilmiştir. Ayrıca iplik kalitelerinin kullanılan iğnelerin aşınmalarında farklı etkiler gösterdiği de belirlenmiştir. Anahtar Kelimeler: Örme iğnesi, SEM stereoskopi, ortalama yüzey pürüzlük parametresi
Vehicle routing in a fuzzy environment using ant colony optimization approach
Get PDFBu çalışmada, bulanık kümeler ve olabilirlik teorilerinden faydalanılarak zaman aralıklı araç rotalama problemi (ZAARP) için bulanık karar ortamında kullanılabilecek bir gürbüz bulanık programlama modeli önerilmiştir. Geçmiş çalışmalar incelendiğinde ZAARP'nin genellikle parametrelerindeki belirsizliklerin ve kısıtlarındaki esnekliklerin göz ardı edilerek modellendiği görülmüştür. Bu tip modellere üretilen çözümler uygulama aşamasında çoğunlukla geçerliliklerini yitirmekte ve kullanıcılar tarafından elle düzeltilmeyi gerektirmektedirler. Stokastik modellerin kullanıldığı çalışmalarda ise önerilen modellerin çok fazla hesaplama yükü gerektirdiği ve parametrelerinin belirlenmesi için problemle ilgili geçmiş verilere ihtiyaç duyulduğu görülmektedir. Bu nedenlerle stokastik modeller de gerçek hayatta karşılaşılan problemlerin çözümünde rahatlıkla kullanılamamaktadır. Bu çalışmada belirsizliklerin ve esnekliklerin modellenmesi için bulanık aralıklar ve bulanık kümeler kullanılmıştır. Gereklilik ve olabilirlik ölçütleri ile planlayıcının belirlediği eşik güvenilirlik ve müşteri tatmini düzeylerine sahip çözümler oluşturulmuştur. Bulanık programlama modeli ile yüksek veri işleme maliyeti düşürülürken modellerin geçerlilikleri de arttırılmıştır. Önerilen modellere çözüm oluşturmak amacıyla karınca kolonisi optimizasyonu tabanlı bir algoritma geliştirilmiştir. Bulanık değerler kesin değerlerin genelleştirilmiş hali olarak ele alındığından geliştirilen algoritma kesin veri ve/veya bulanık veri durumlarında çözüm oluşturabilmektedir. Örnek problemler üzerinde gerçekleştirilen deneylerde planlayıcıların tercih ve önceliklerine göre alternatif çözümlerin üretilebileceği ve oluşturulan çözümler hakkında planlayıcılara ve müşterilere daha fazla bilgi sağlanabileceği gösterilmiştir. Anahtar Kelimeler: Bulanık kümeler, olabilirlik teorisi, araç rotalama problemi, karınca kolonisi optimizasyonu.Many companies use fleets of vehicles within their activity in a range of sectors. More often than not, meeting customers' requirements, taking into account their geographical spread and delivery time windows, as well as managing the company's operating and financial constraints, turns into a nightmare. The vehicle routing problem with time windows (VRPTW) is a well-known and complex combinatorial optimization problem concerned with finding efficient routes, beginning and ending at a central depot, for a fleet of identical vehicles to serve a number of customers with capacity and time window constraints where each customer is visited exactly once by a vehicle. The capacity constraint signifies that the total load on a route cannot exceed the capacity of the assigned vehicle. The time window constraint signifies that each vehicle must start the service each customer in the period specified by the customer. The objective is to find the feasible solution (hierarchically or not) with minimal number of vehicles or with the minimal total distance. VRPTW has been a subject of intensive research focused mainly on the heuristic and the metaheuristic approaches. The VRPTW is still one of the most difficult problems in combinatorial optimization and this problem contributes directly to a real opportunity to reduce costs in the important area of logistics. Transportation management, and more specifically the vehicle routing, has a considerable economical impact on all logistic systems. However, the classical definitions of the vehicle routing problem often lack handling of uncertain parameters and flexible constraints such as the traveling times between customers and the latest delivery times for the custoners. In addition, a best/optimal solution generated by a heuristic/exact method, for the classical VRPTW do not mean any knowledge to the user about its realization when applicated. Whereas, the solutions generated with the classical models usually became infeasible when implemented and the planners are often involved to make corrections by hand. The natural approach to modeling the uncertainty is a stochastic one. Unfortunately, the stochastic models are often hard to solve. Moreover, it may be hard or expensive to assume any speci?c probability distributions for the unknown parameters. For these reasons stochastic models are behind the needs of users. Up to past decades, operational research methods seem to be inadequate for the large sized combinatorial optimization problems due to their large computational effort and long solution time. But, recent developments in data processing and communication technologies and recently proposed metaheuristic methods that can generate solutions to large sized combinatorial problems made these classical disadvantages less important for the researchers. Subsequently, validity of used models became a more important issue for the researchers. In this study, the fuzzy set and the possibility theories are utilized in order to propose a fuzzy robust programming model for the VRPTW that can be used in the uncertain decision environments. The fuzzy programming model proposed in this study exploit fuzzy sets and fuzzy intervals in order to model flexibilities on latest delivery times and uncertainties for traveling times between customers. A necessity measure is used to generate knowledge about the satisfaction of delivery time constraints when a route is realized by the vehicle. In addition, a possibility measure is used to evaluate the customer satisfaction levels. Using the necessity and the possibility measures, solutions that have the maximum risk level to be unfeasible and the minimum customer satisfaction, which are specified by the user, can be generated. Validities of the models are increased while decreasing the computational effort with fuzzy programming models. In order to generate solutions for the proposed model an ant colony optimization based algorithm is developed. The algorithm is capable of solving both the classical and the fuzzy programming models for the VRPTW. Results of the experimental studies with the benchmark problems indicate that the proposed fuzzy programming model and the ant colony optimization algorithm can be usable for solving practical problems in means of solution time and quality. The proposed approach can be integrated with a decision support system in order to generate alternative solutions achieving the planners' and the customers' preferences along with acquiring more information about the realization of the solutions. Keywords: Fuzzy sets, possibility theory, vehicle routing problem, ant colony optimization. 
Evaluating the effects of soy ingredients on soy bread properties
Get PDFBu çalışmada, soya ürünlerinin fonksiyonel gıda bileşenlerinin belirlenmesi ve özellikle yeni bir soya ürünü olan Soya Sütü Tozunun (SST) ekmek özellikleri üzerine etkilerinin açıklığa kavuşturulması amaçlanmıştır. Bu amaçla SST’nin içerdiği bileşenleri ayrı ayrı içeren çeşitli ticari soya ürünleri ekmeğe ilave edilerek kalite özellikleri ayrıntılı şekilde incelenmiştir. Fonksiyonel bileşenler kapsamında soya ürünlerinde; fenolik madde miktarı ve profili, izoflavon miktarı ve profili ve antioksidan aktiviteler analizlenmiş ve kimyasal kompozisyon belirlenmiştir. Daha sonra SST’nin içerdiği bileşenlerle soya ekmekleri üretilmiş, taze ve depolanmış ekmeklerde kaliteyi etkileyen fiziksel ve fizikokimyasal özelliklere her bileşenin etkileri belirlenmiştir. Soya Sütü Tozu (SST), Soya Unu (SU), Soya Lifleri (Çözünür-ÇSL ve Çözünür Olmayan-ÇOSL) ve Soya Protein İzolatları (SPI, farklı denatürasyon derecelerinde) ile üretilen soya ekmeklerinde kompozisyon analizleri (nem, kül, protein, diyet lifi), fiziksel özellikler (ekmek hacmi, sertliği, ekmek içi ve kabuk rengi) ve fizikokimyasal özellikler (su aktivitesi, nem içeriği, dondurulabilir/dondurulabilir olmayan su miktarları, amilopektin kristallenmesi, sıkılık) depolama süresince analizlenmiştir. Soya ürünlerinde en yüksek fenolik madde, izoflavon miktarları ve antioksidan aktiviteleri SU ve SST için elde edilmiştir. Ekmeklerde hacim artışı ve yumuşaklığa ÇSL neden olurken, SPI 1 ve ÇOSL olumsuz etkiler göstermiştir. Depolama süresinde SST’nin bayatlamayı geciktirdiği ve bu etkinin çözünür lif ve yağ içeriğinin birlikte etkileriyle olduğu ve ÇOSL’nin ise bayatlamayı olumsuz yönde etkilediği belirlenmiştir. Soya sütü tozu ilavesi hem fonksiyonel bileşenler açısından zenginleştirme, hem de ekmek özelliklerinin geliştirilmesi açısından ekmek formülasyonlarında yararlı bir bileşen olarak ortaya çıkmaktadır. Anahtar Kelimeler: Soya ürünleri, soya ekmeği, bayatlama.Positive health effects of soybean can be supplied to consumers via soy products that are widely consumed and having acceptable quality. Nowadays, soy bread is becoming one of the best food product for presenting those advantages to consumers. Use of soy ingredients in bakery products is quite limited as they yield breads having less acceptable sensory, textural and quality characteristics. The objectives of this study were to determine the functional food components of soy products and examine the role of each soy milk component on the functionality of soy-containing bread in order to understand the impact of soy milk powder (SMP) on physical and physicochemical properties of soy bread. In this content, firstly the properties of functional components in soy based ingredients were characterized. Afterwards, soy breads were produced by additions of soy based ingredients at levels that were simulating the components of SMP, and the effect of each component was determined on fresh and stale soy breads by evaluating the physical and physicochemical properties that were effective in bread quality. Chemical compositions; soluble and insoluble fiber fractions, protein and moisture contents of soy ingredients such as SMP, soy flour (SF), soy fibers (soluble-SDF and insoluble-ISDF), and soy protein isolates (SPI, at different denaturation levels) were determined. In the extent of functional component evaluation in soy products, phenolic contents/profile and isoflavone contents/profile were determined using reversed phase HPLC methods and antioxidant activities were analyzed by DPPH and ABTS radical scavenging activity methods. Soy breads were produced by addition of each ingredient as SMP, SF, soy fibers (SDF and ISDF) and SPIs (at different denaturation levels) in order to simulate SMP, and breads were stored for 7 days. In those breads, proximate analysis (moisture, ash, protein, dietary fiber) were carried out. In addition, physical properties (loaf volume, firmness, crumb and crust color) and physicochemical properties (water activity, moisture content, freezable water content, unfreezable water content, amylopectin crystallisation, stiffness) of breads were determined during storage by thermal analysis techniques. Soy products were found to be significantly different in their functional components and properties. SMP, in addition to its lower insoluble fiber content (14.2%) compared to that of SF (21.3%) also involved little more soluble fiber than SF. The highest phenolic contents in soy products were obtained for SF (3.15 mg GA/g sample), SMP (2.80 mg GA/g sample), and partly denatured SPI ingredients (2.02 mg GA/g sample). In addition, SF (2860.1 ppm) and SMP (1917.1 ppm) contained higher amounts of isoflavones and antioxidant activities than all other soy products. Insoluble fiber (10.4%) and soy protein additions (9.7-13.0%) significantly decreased loaf volumes. On the other hand, soluble fiber addition increased loaf volume (1.3%). The negative effect of SMP addition on loaf volume was associated to the higher insoluble soy fiber and soy protein contents. Addition of SPI, with its high protein content, increased bread firmness. On the other hand, soluble fiber addition provided significant softness in soy breads. At the end of storage significant differences in crumb and crust colors were found in each formulation. Generally, staling induced slight changes in crumb color. However, crust color got darker in all formulations. Moisture contents of breads decreased during staling. As the content of soy based ingredients increased, the amount of water held in bread matrix also increased. Highest moisture contents in breads were obtained with insoluble fiber (47.27%) and soy protein additions (47.63%). Soluble and insoluble fiber additions increased freezable water content in all fresh breads with respect to SF (10.0-16.3%). Lowest unfreezable water contents were observed in fiber added breads (12.3-14.3%). It was obvious that fiber additions significantly changed bread firmness during 7 days of storage. This change in firmness was found to be highest for soluble soy fiber (approximately 5 fold) and lowest for SMP (12.3%) additions. Amylopectin crystallisation increased in all breads during storage. Insoluble fiber additions significantly increased amylopectin crystallisation (from 0.01 W/g to 0.57 W/g). Soluble fiber additions (0.30 W/g) retarded staling with respect to SF bread (0.39 W/g). Especially, the lowest enthalpy obtained for SMP (0.12 W/g) added bread was attributed to possible synergistics effect of its soluble fiber and/or oil content of this ingredient. Keywords: Soy products, soy bread, bread staling
Dar su yollarında manuel kumanda ile seyir yapan gemilerin konumunun yapay sinir ağı kullanılarak öngörülmesi
Get PDFDespite modern navigation devices, there are still some problems for navigating of vessels in narrow waterways because of geographical structures and various disturbances. In this study, guidance and a early warning method have been developed for navigation in narrow waterways. The Istanbul Strait has been specifically studied as a model. The basis of this study is to predict the future coordinates of a manually controlled vessel using Artificial Neural Networks (ANN). The method could be utilized for warning system by Vessel Traffic Services (VTS) operators and guidance system by vessel crew. Even though all vessels have modern navigation devices, use of autopilot is not allowed in the Strait. Vessels have to be manually controlled according to rules. A human operator (helmsman) controls a vessel as a continuous system manually according to captain’s command against random disturbances through strait of Istanbul and their behaviour affects the course and coordinates of the vessel. In this study, Artificial Neural Networks have been trained by using position and speed data collected from vessels which navigated manually in the strait and they included effects of environmental conditions and geographical characteristics of the strait. Three-minute-ahead-position of vessels have been predicted by using the trained ANN. Some experiments have been realized in İstanbul VTS centre and it has been observed that the method satisfied the goal in especially turning points of the strait. VTS operators can watch only straight bearing of vessels on VTS panels but especially for turning regions, they have to notice a risk on time which may result with a disaster because of negligence of the vessel crew. Latitude and longitude (x,y), course (y), speed (u) and time ( t) data have been collected from GPS of 4 vessels in 1 minute sampling period to train Artificial Neural Networks. Then the trained ANN has been used to predict , positions. Data from vessels, navigated to south and north, have been used to determine model structures. Although the course is stable on the reference line between two turning points, vessels can change its course if it is between traffic separation lines. The direction of vector, from x[k-1], y[k-1] to x[k], y[k], gives the course of the vessel. These data includes speed data because they were recorded in 1 minute sampling period. So, only position data considered to decide model structure and used for training of Neural Networks. On-line prediction has been tested at the VTS centre in Istanbul. and, it has been confirmed that, there is no early warning and guidance system as intended in this study, either in Turkey or in another country to use along with VTS systems. Warning mission is currently realised by certificated and experienced operators. The prediction results evaluated together with VTS operators. They found the prediction performance satisfactory and stated that they need minimum of 2 minutes to prevent a probable risk. Currently a Straight bearing line is shown on the VTS operator panels and it represents vessels’ course but it’s not useful especially on the turning regions. The proposed method has been particularly formed for prediction of turning course and the prediction performance was found to be successful on the turning regions. Error analysis has been made for examining differences between predicted position and real position of the vessel. Three different methods can be suggested for prediction. As in this study; data file of the vessel has been updated and Neural Networks have been trained in 1 minute sampling period and then 3-minute-ahead position has been predicted with trained Neural Network. As another possible method; Trained Artificial Neural Networks (TANN) libraries can be constituted by collecting data statistically from vessels navigate in Strait depending on the current environmental conditions. Finally as a third option, special TANN libraries can be constituted by keeping the past data of any specific vessel and it can be later used for the same vessel and of course environmental conditions should also be considered. In addition, if VTS operators can watch the course prediction instead of straight bearing on operator panels for vessels navigating in opposite directions in straits, the algorithm can be expanded to make “collision prediction” for early warning in especially turning regions and this issue can be studied also in future. Keywords: Artificial Neural Networks, manual control, navigation, prediction. Gemilerin dar sulardan geçişleri, maruz kalınan bozucular ve coğrafi yapı nedeniyle çok gelişmiş seyir cihazlarına rağmen sorun olmaya devam etmektedir. Birçok ülkede dar sularda emniyetli geçişin sağlanması amacıyla, belirli aralıklarla yerleştirilmiş radarlar vasıtasıyla geçiş yapan gemilerin izlenmesi ve bu sayede çarpışma, karaya oturma ve diğer şekillerde oluşabilecek kaza risklerinin azaltılması için Gemi Trafik Hizmetleri Merkezleri (GTH) görev yapmaktadır. Bu çalışmada, İstanbul Boğazı model alınarak, GTH merkezinde erken uyarı sistemi ve geçiş yapan gemilerde seyir yardımcısı kılavuz olarak görev yapacak bir yöntem geliştirilmiştir. Boğaz kazalarının, gemilerin trafik ayrım düzeni sınırlarını ihlal etmeleri nedeniyle meydana geldiği bilindiğinden, ihlalin önceden tespiti ile tehlike riskini azaltmak ve olası kazaları engellemek hedeflenmiştir. Özellikle görüşün azaldığı, alt akıntının arttığı durumlarda ve 45 dereceden daha yüksek manevralarda kaza riski artmaktadır. GTH merkezinin imkânlarından faydalanılarak, manüel olarak kumanda edilmek suretiyle boğaz geçişi yaptırılan gemilerin tüm çevre şartlarına bağlı olan hareketine ait verilerinden faydalanarak yapay sinir ağı eğitilmiş ve eğitilmiş yapay sinir ağı (EYSA) ile İstanbul Boğazı’nın coğrafi ve oşinografik özelliği göz önüne alınarak kabul edilmiş süre olan 3 dakika sonraki yerleri öngörülmüştür. Gerçek zamanlı olarak yapılan öngörü GTH personeli ile değerlendirilmiş ve en az 2 dakikalık öngörünün kendileri için faydalı olacağı tespit edilmiştir. Vektörel hata analizleri de yapılarak öngörünün istenen seviyede olduğu görülmüştür. Anahtar Kelimeler: Yapay Sinir Ağları, manüel kontrol, navigasyon, öngörü.  
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