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Effects of process parameters and tool wear on the fatigue life of machined threaded parts
Get PDFTalaş kaldırılarak tornada açılmış vidalı parçaların yorulma dayanımına imal faktörleri ve koşullarının etkileri, vida diş formundaki çentikli numunelerin yorulma dayanımları ile karşılaştırılarak araştırılmıştır. Vida açmada kesme hızının, radyal ilerlemenin, takım aşınmasının ve iki farklı kesme şemasının vidalı numunenin yorulma dayanımına etkileri bulunmuştur. Deneylerde vidalı numunelerin yorulma dayanımları aynı formdaki çentikli numuneye göre imal faktörlerine bağlı olarak geniş bir dağılım göstermiştir. Vidalı numunenin yorulma dayanımının imal faktörlerine önemli derecede bağlı olduğu ve çentikli numunenin vidayı temsil etmediği görülmüştür. Vidalı numunenin yorulma dayanımında en fazla takım aşınmasının ve kesme hızının daha düşük oranlarda ise kesme şemasının ve radyal ilerlemenin etkili olduğu görülmüştür. Anahtar Kelimeler: Vida kesme, yorulma, takım aşınması. The effect of the machining parameters on the fatigue life of the threaded parts manufactured by machining were investigated comparing with the endurance limits of same size fine machined notched specimens. To machine precise specimens, rigidity of a universal lathe was improved by an additional slide system, and the final rigidity was measured to make sure of the tight dimensional tolerances. An R. R. Moore four point rotary bending fatigue test machine was designed, manufactured and calibrated. All the specimens were machined from AISI 4340 steel. In both thread and notch machining, uncoated %78 WC, %14 TiC and %8 Co API special tapered pipe thread tools were used. The effects of the cutting force, radial feed, tool wear and two thread cutting feeding methods on the fatigue life of the threaded specimens were determined. Experimental results show that fatigue lives of threaded specimens lie on a large range depending on machining conditions as compared to notched specimens, and thus, notched specimens do not represent fatigue behavior of threaded specimens. According to the experimental results, the most important factors effecting fatigue life of threaded specimens were found to be tool wear and cutting velocity and the effects of the different feeding methods and radial feed were found less significant. Keywords: Thread machining, fatigue, tool wear.
Modelling of streamflow series using wavelet transform technique
Get PDFÇalışmada işaret işleme sahasında kullanılan dalgacık dönüşümü tekniği hidrolojik akım serilerinin tahmininde kullanılmıştır. İlk olarak sürekli dalgacık dönüşümü ve global spektrum yardımı ile ölçüm serileri analiz edilmiştir. İki ayrı ölçüm istasyonuna ait akarsu akım serileri ayrık dalgacık dönüşümü uygulanarak bileşenlerine ayrılmıştır. Elde edilen bileşenler geliştirilen regresyon tipi bir model yardımı modellenmiştir. Modelde tahmin eden ve tahmin ettirici değişkenler yerine akım serilerinin ayrık dalgacık dönüşümü bileşenleri kullanılmıştır. Elde edilen sonuçlar farklı hata kriterleri ile değerlendirilmiştir. Modelleme sonuçlarında bölgenin iklim karakteristiğine uygun bileşenler arasında kurulan modellerin diğer modellere göre bir çok hata kriteri bakımından daha başarılı olduğu görülmüştür. Anahtar Kelimeler: Akarsu akım serilerinin modellenmesi, dalgacık dönüşümü. Even though earth science phenomena have nonstationary characteristics, they actually include many different secret periodic events occurred in different time periods. Wavelet transform gives better results than former techniques for analyzing these phenomena. In this study, a new modelling technique using discrete wavelet transform, which is a special type of wavelet transform, is presented to increase prediction performance of streamflow time series modelling as an earth science phenomena and to provide physical interpretation. Different periodic components of a streamflow series are always obtained using discrete wavelet transform. The present study differs in that discrete wavelet transform is firstly presented as a modelling technique with application on streamflow process. Instead of response and explanatory measured streamflow series in a linear regression model, discrete wavelet components of such series are used in this study. First of all, discrete wavelet components of streamflow series are analysed by continuous wavelet transform and global wavelet spectrum. Secondly, energy variation of each component of both measured series is calculated. If appropriate components obtained by discrete wavelet transform are used, the performance of streamflow models can be increased. This technique is applied to regression models, because they are simple and widely used in practical applications. Energy variation, correlation coefficients and error values of the constituted models are compared with each other. This new technique offers good advantage in streamflow modelling. Keywords: Modelling of streamflow series, wavelet transform.
A particle swarm optimization for the job shop scheduling problems
Get PDFPopülasyon temelli sezgisel yöntemlerden biri olan Parçacık Sürü Optimizasyonu (PSO), kuş ve balık sürülerinin sosyal davranışlarından etkilenerek geliştirilen yeni bir eniyileme yöntemidir. Bu makalede, zor çizelgeleme problemleri arasında yer alan Atölye Tipi Çizelgeleme problemlerinin çözümü için, bir PSO modeli, Değişken Komşuluk Arama yöntemi ile birlikte geliştirilmiştir. Oluşturulan bu model, tamamlanma zamanı performans ölçütüne göre literatürde yer alan bazı zor test problemleri üzerindeki sonuçları incelenmiş ve iyi sonuçlar veren diğer sezgisel yöntemlerin sonuçlarıyla karşılaştırılmıştır. Sonuçta genel olarak önerilen modelin diğer yöntemlere göre daha iyi veya eşdeğer seviyede olduğu görülmüştür. Anahtar Kelimeler: Atölye tipi çizelgeleme, parçacık sürü optimizasyonu, sezgiseller.Particle Swarm Optimization (PSO) is one of the population based optimization technique inspired by social behavior of bird flocking and fish schooling. PSO inventers were inspired of such natural process based scenarios to solve the optimization problems. In PSO, each single solution, called a particle, is considered as a bird, the group becomes a swarm (population) and the search space is the area to explore. Each particle has a fitness value calculated by a fitness function, and a velocity of flying towards the optimum, food. All particles fly across the problem space following the particle nearest to the optimum. PSO starts with initial population of solutions, which is updated iteration-by-iteration. Therefore, PSO can be counted as an evolutionary algorithm besides being a metaheuristics method, which allows exploiting the searching experience of a single particle as well as the best of the whole swarm. In this paper, A PSO model for the job shop scheduling problem is proposed. In addition, a simple but efficient local search method called Variable Neighborhood Search (VNS) is embedded to the PSO model and applied to several hardest benchmark suites. The results for the PSO algorithm with VNS are also presented and compared with many efficient meta-heuristic algorithms in literature. As a final result, PSO with VNS results are generally found to be better than other results. Keywords: Job shop scheduling, particle swarm optimization, Meta-Heuristics
Progressive transmission and image oriented compression of turbo coded images
Get PDFBu çalışmada, haberleşme kanalında turbo kodlamalı olarak iletilen görüntü kalitesinin alıcıda aşamalı bir biçimde ayarlanabilmesine olanak sağlayan bir metot önerilmiştir. Görüntü önce maskelenmiş sonra her bir maske belli sayıda bit düzlemleriyle ifade edilmiş, kodlanmış daha sonra da iletim kanalına verilmiştir. Maskelere ait bit düzlemi sayısı görüntüye ait detaylar tarafından belirlenmiştir. İstenen görüntü kalitesinin aşamalı olarak elde edilebilmesi amacıyla, verici, görüntüye ait bilgileri kodlanmış olarak göndermeye devam eder. Alıcıya bu bilgiler aşamalı olarak geldikçe En Büyük sonsal algoritması yardımıyla kod çözme işlemi yapılır ve bit düzlemleri yeniden oluşturulur. Böylece görüntü detaylarının (www tarayıcılarında olduğu gibi) ard arda elde edilmesi sağlanmış olur. Anahtar Kelimeler: Turbo kodlama, bit düzlemi, aşamalı resim iletimi, en büyük sonsal.In this chapter, we propose a method, that allows turbo coded images to transfer efficiently, in which the data amount and the quality passed to the receiver can be adjusted. The procedure is based on the idea that only partial information from the original image is provided to the receiver at each step. The receiver will use the limited information and perform the enhancement. At first, the image is partitioned (masked), bit sliced, turbo coded and transmitted progressively through the communication channel. The number of bit planes of each mask is determined according to the details. In order to extract the quality of the image, the transmitter sends the coded bit planes of each mask continuously. Since the coded planes are collected at the receiver progressively, they are decoded via MAP (Maximum A posteriori Probability) algorithm reconstructing the bit planes and then the masks. So the whole image is built at the receiver. By this way, the details or additional information about the image is updated (like www browsers) at each step. So, the new data, together with data already on the receiver side, is used to build a new and more complete image at the receiver, achieving a better image representation. This procedure is iterated, according to the need of quality satisfaction. Keywords: Turbo coding, bit plane, progressive image transmission, maximum a posteriori probability
Modeling prefrontal cortex functions using artificial neural networks
Get PDFBu çalışmada, değerlendirme testleri ile ölçülmeye çalışılan prefrontal korteks işlevlerini modellemek amacıyla işlemsel modeller önerilmiştir. Modelleme aracı olarak, yapay sinir ağları kullanılmıştır. Literatürde prefrontal korteksin amaca yönelik davranış geliştirmek için gerekli olan yüksek seviyeli bilişsel işlevlerden sorumlu olduğu önerilmektedir. Bu çalışmada esneklik, soyut düşünme ve amaca yönelik davranış geliştirme işlevlerini ölçmekte sıklıkla kullanılan Wisconsin Kart Eşleştirme Testi ve Stroop testi ele alınmıştır. Her iki test için önerilen modellerin sağlam ve prefrontal hasarlı deneklerin performanslarını üretebilme yetenekleri benzetimler ile sınanmıştır. Benzetim sonuçları modellerin klinik verilere uygun sonuçlar ürettiğini göstermektedir.Anahtar Kelimeler: Prefrontal korteks, yapay sinir ağları, Wisconsin Kart Eşleştirme Testi, Stroop testi.In this work, computational models for prefrontal cortex functions during the evaluation tests are proposed. Artificial neural networks are used as modeling tools. In the literature the prefrontal cortex is suggested to be responsible for high order cognitive abilities needed for goal-directed behavior. Wisconsin Card Sorting Test and Stroop test which are the representative ones for measuring mental flexibility, abstract thinking and goal directed behavior are considered in this work. The first step of modeling approach taken in this work is to propose the hypothetical tasks/subtasks which are supposed to be performed by the subject to complete considered tests successfully. At the same time these tasks must be defined in terms of the processes which are executed by the prefrontal circuits. After the test material and application of the test are simulated in a software environment which is developed using MATLABâ, the tests are applied to the model and the results are scored following the test evaluation rules like a real subject. The most important point of the modeling is to simulate the behavior of the PFC. Keywords: Prefrontal cortex, artificial neural networks, Wisconsin Card Sorting Test, Stroop test
Effect of plasma (ion) nitriding on performance of cemented carbide tool inserts
Get PDFBu çalışmada, talaş kaldırmada kullanılan sinterlenmiş karbür plaketler değişik nitrürleme şartları altında iyon nitrürlenmişler ve belli talaş kaldırma şartları altında kullanılarak ömür performansları araştırılmıştır. Diğer bir ifadeyle plazma nitrürlemenin plaket performansı üzerindeki etkisi incelenmiştir. Bu amaçla, sert metal plaketler değişik nitrürleme parametreleri (sıcaklık, süre ve gaz karışım oranı) altında nitrürlenmişler ve nitrürleme sonrasında plaket özelliklerinde (yüzey sertliği, yüzeyde oluşan tabaka kalınlıkları, sürtünme katsayısı) meydana gelen değişimler izlenmiştir. Ayrıca nitrürlenmiş ve nitrürlenmemiş plaketler talaş kaldırma deneylerine tabii tutularak, plaket aşınmaları ölçülmüştür. Böylece nitrürleme parametreleri ile plaket özelliklerinde meydana gelen değişimler ilişkilendirilerek, iyon nitrürlemenin plaket performansı üzerindeki etkisi incelenmiştir. Anahtar Kelimeler: Plazma (İyon) nitrürleme, yüzey sertliği, sürtünme katsayısı, serbest yüzey aşınması.In this study, inserts ion nitrided in various conditions, are used in certain cutting conditions in order to investigate life performance. In other words the effect of ion nitriding on cemented carbide tool insert performance is investigated. Therefore, inserts are ion nitrided in various nitriding parameters such as nitriding time, nitriding temperature and gas mixture ratio. Each insert surface hardnesses were measured before and after plasma nitriding experiments. At the same time untreated insert surface hardnesses were also measured. Cutting process experiment has been started after nitriding experiments. Untreated inserts were also used in the same cutting operation. Flank wear of nitrided and untreated inserts were also measured. It is known that plasma nitriding has been particularly effective in improving tribology properties and wear resistances. Therefore, friction coefficient of nitrided and untreated inserts were measured. Compound layer thickness and diffusion layer thickness of nitrided inserts were also measured and related to the nitriding parameters. Finally, inserts were nitrided in sistematically changed nitriding conditions and experimented under certain cutting processing conditions. At the same time, surface hardness, friction coefficient, flank wear, thickness of compound layer and thickness of diffusion layers were measured at a suitable time. By this way, the effects of ion nitriding parameters on cemented carbide tool inserts is investigated.Keywords: Plasma (ıon) nitriding, surface hardness, friction coefficient, flank wear
Applications of soft computing methods in geodesy
Get PDFBu çalışmada Yapay Sinir Ağları (YSA) ve Bulanık Çıkarım Sistemleri (BÇS) jeodezinin en önemli problemlerinden bazılarının çözümü için kullanılmıştır. Bu problemler sırayla, Yer yuvarı gravite alanının modellenmesi ve de GPS/Nivelman ölçülerinden geoid yüzeyinin belirlenmesidir. Gravite alanı modellemesi için GRACE (Gravity Recovery And Climate Experiment) uydu gravimetre verileri,GPS/Nivelman geoidi için ise İzmir metropolitan GPS nirengi ağında yapılan GPS ve nivelman ölçülerinden türetilmiş geoid yükseklikleri bilinen kontrol noktaları kullanılmıştır. Her iki uygulama sonucunda esnek hesaplama yöntemlerinin, özellikle girdi-çıktı sistemleri şeklinde tanımlanan jeodezik problemlerin çözümü için uygun yöntemler olduğu sonucuna varılmıştır. Anahtar Kelimeler: BÇS, geoid,GRACE, gravite alanı,YSA.Soft computing methods such as artificial neural networks (ANN) and fuzzy inference systems (FIS) have been widely used methods in various science and engineering fields. As the backgrounds of these methods are not very old, they have shown a rapid development with the improvements in computer systems and computation techniques. Their use in geodesy is quite new. In this study, both ANN and FIS have been used to solve the some of the major problems in geodesy. These problems are modelling of Earth’s gravity field and the determination of geoid surface from GPS/Levelling. For gravity field modeling, GRACE (Gravity recovery And Climate Experiment) satellite gravimetry data, and for GPS/Levelling geoid control points with known geoid heights derived from GPS and levelling measurements in İzmir metropolitan GPS network were used The results from the soft methods used in computations were also compared with those from the conventional methods in terms of model quality measures like root mean square (RMS) error, mean error, mean absolute error, error range, correlation coefficient. Both applications’ results have concluded that soft computing methods are appropriate methods for the solution of geodetic problems especially which can be defined as input-output systems and should be considered for the solution of different other problems in geodetic science. Keywords: ANN, FIS, geoid,GRACE, gravity fiel
A Numerical approach to changes in rock properties by weathering and alteration
Get PDFKayaçlar iç ve dış etmenler ile sürekli bir değişimin altında kaldıkları süreç içinde bünyelerini (maddelerini) etkileyen oluşumlara; fiziksel, kimyasal, mineralojik, petrografik, mekanik ve elastik özelliklerindeki farklı değişimler ile tepki verirler. Bu çalışmada kayaçların bünyesinde ayrışma ve alterasyona bağlı gelişen değişim, her Pi(xi,yi) koordinatında noktasal ve formasyon bütününde genel (alansal) tanımlanmıştır. Araştırma, ayrışma ve alterasyon etkisinde kaldığı bilinen Çanakkale ili Tuzla jeotermal sahasındaki 70 km2 lik alanda görülen kayaçlar üzerinde yapılmıştır. Çalışmada inceleme alanındaki jeolojik ve mühendislik özellikleri belirlemiş, kayaçların bünyelerindeki değişim için fiziksel ve maddesel özelliklerinden yararlanılmıştır. Maddesel (bünyesel) özelliklerin sayısal değerleri, yönlü kayaç örneklerden hazırlanan yönlü ince kesitlerin polarizan mikroskop görüntülerinin ilgili yazılımlar ile bilgisayarda sayısallaştırılması ile elde edilmiştir. Bu şekilde elde edilen sayısal görüntü değerleri, kayacın alınmış olduğu Pi(xi,yi) koordinatındaki maddesi (bünyesi) nin sayısal değeridir ve bu, kayacın oluşumundan günümüze kadar geçirdiği tüm olayların sayısal ifadesi olarak değerlendirilmiştir. Anahtar Kelimeler: Noktasal kayaç değişimi,Genel kayaç değişimi,Fiziksel özellik, Sayısal görüntü değeri. The rock occurrences in different places in the world exhibit weathering-alteration processes occurred by external and internal conditions. These factors affect rocks by changing their physical, chemical, mineralogical, petrographical, mechanical and elastic properties. In this study, the numerical definition of these changes on rock body have been tried to be obtained. As the fact of that, the numerical definitions of these changes on the rock body under the control of the internal and external factors which will be more efficient than those of the verbal ones. In this study was applied in Tuzla geothermal area of 70 km2 placed in Çanakkale. And the results were obtained by using physical properties which were taken from rock samples picked up from the investigation area and image analysis data which were taken from thin section of the rock specimens. The image analysis data which exhibits the rock specimens? conditions represents the all phenomena that rock has them. At the end of this study, the numerical values? changes on the rock specimens which changes between the zero and one were determined by using their physical parameters at every Pi(xi,yi) coordinate. Moreover, the area identification of the rock changes at every target zone or formation was determined by using the physical properties and the image analysis values. The rock alteration values? changes between the zero and one shows that the sequence of light and heavy changes of the rock specimens. Keywords: Rock alteration value, physical parameter, numerical image value
Mathematical modeling and simulation of photopolymerization process in stereolithography
Get PDFUltraviyole (UV) ışın etkisi ile bir sıvı reçinenin istenilen geometriye sahip katı cisimlere dönüşümünü sağlayan stereolitografi tekniğinin temel süreci olan fotopolimerizasyon sürecinin anlaşılması, stereolitografi tekniğinin kullanıldığı üretimler için kritik öneme sahiptir. Çalışma koşullarının fotopolimerizasyon sürecine olan etkilerinin belirlenmesi, stereolitografide istenilen boyutta ve kalitede ürünün elde edilmesini sağlamaktadır. Bu çalışmada, stereolitografi cihazında farklı koşullarda gerçekleştirilen fotopolimerizasyon sürecinin simulasyonu için deterministik yaklaşımı temel alan bir matematiksel model geliştirilmiştir. Geliştirilen matematiksel modeli oluşturan iki boyutlu kısmi diferansiyel denklemlerin çözümü COMSOL paket programı yardımıyla sonlu farklar yöntemi uygulanarak belirli sınır koşulları için çözülmüştür. Bu modelde, fotopolimerizasyon sırasında gerçekleşen kimyasal tepkimelere (başlama, yayılma, sonlanma ve yavaşlama) ait kinetik eşitliklerin yanısıra ısı ve kütle aktarım etkilerini temsil eden eşitlikler de göz önünde bulundurulmuştur. Matematiksel modelin, stereolitografide fotopolimerizasyon yoluyla katı cisim oluşma sürecini başarılı bir şekilde tanımlayabildiği görülmüştür. Simulasyonlar UV ışın kaynağının üç farklı tarama hızı (2.72x10-1 m/s, 2.72x10-2 m/s ve 1.18x10-2 m/s) için yapılmıştır. Simulasyon sonuçları, UV ışın kaynağının tarama hızındaki değişimin tepkime dönüşümüne olan etkisini ve buna bağlı olarak katı cismin boyutlarında meydana gelen değişimi de açıkça ortaya koymuştur. Yapılan simulasyonlar sonucunda UV ışınının reçine içindeki derinliğine bağlı olarak tepkime dönüşüm eğrileri elde edilmiş ve bu eğrilerin yardımıyla fotopolimerizasyon sonucu oluşacak katı cismin boyutları belirlenmiştir. Anahtar Kelimeler: Fotopolimerizasyon, matematik modelleme, stereolitografi.Stereolithography (SL) is one of the most widely used and cost-effective method for creating three-dimensional objects from thin layers of hardened liquid polymers. Generally, an intense ultraviolet (UV) light source is used to solidify these liquid polymers, which are also known as resins, from a series of consecutive two-dimensional (2-D) cross sections. Often data from computer-aided design software is used to control the precise movements of the UV light source as it builds the object. The resulting product may serve as a prototype for engineering designs before its mass production and for low-volume manufacturing applications. Photopolymerization, which is the underlying basic reaction mechanism of SL has a wide range of applications such as: creating decorative and protective coatings, fabricating biomedical prostheses, contact lenses, dental restorations, manufacturing electronic components paints or printing inks, composite materials, and making fiber optic coatings. In SL technique a liquid resin is converted to a solid object of desired geometry by photopolymerization process. Thus, the modeling and simulations of the photopolymerization process that takes place in SL is very important for products manufactured by this technique. The determination of the variation of photopolymerization reaction conversion and the gelation time under different conditions is important for manufacturing products with desired qualities. The absorption of the UV light by the photoinitiator molecules mixed into the resin creates highly reactive radicals, and these radicals interact with the functional groups of monomers that compose the resin. This, in turn, converts the monomers into radicals and starts a chain reaction, which causes a large percentage of the monomers in the resin to ultimately become entangled in a highly cross-linked polymeric network. The key advantages of using light-induced photopolymerization are that such processes tend to be less damaging to the environment; because they generally use smaller amounts of solvents or solvent-free formulations, very high reaction rates at room temperature, spatial control of the process, low energy input; thus being generally economic, and chemical versatility since a wide variety of polymers can be polymerized photochemically.Over the last few decades, a considerable literature has accumulated for the purpose of understanding the kinetics, photoinitiators, polymerization systems, and applications of the photopolymerization process. The most important parameters which govern the photopolymerization process are the tem-perature, the UV light equipment, the UV light penetration depth, the UV light properties (wavelength and intensity), the functionality and reactivity of the monomer, and initial loading concentration and reactivity of the photoinitiator. The kinetics studies mainly measured and simulated double bond conversion and determined the effect of the parameters just mentioned above on the overall double bond conversion. The effect of these parameters on the cure depth of the sample and photoinitiator loading concentration, in contrast, has not been nearly as well studied. In this study, the effect of the scanning speed of the UV light source on the photopolymerization process in SL was simulated. For this purpose, a mathematical model consisting of 2-D Partial Differential Equations (PDE) and based on deterministic approach was developed. This model was solved by using COMSOL package software by application of finite element method. Besides the kinetic equations representing the process reactions, the equations that include the heat and the mass transfer effects in the reaction volume were also considered in the model. The resin chosen for the simulation composed of acrylate monomer, which has four functional units, and the photoinitiator, which has high absorption coefficient at the frequency of the UV light used in the simulations. Simulations were performed for three different UV light scanning speeds of 0.272 m/s, 0.0272 m/s and 0.018 m/s. These speeds chosen so that the resulting polymerized solid objects would have different dimensions. The dimensions of these solid objects were calculated and compared by using the model described above. The simulation results showed that the effect of oxygen inhibition reactions are more dramatic at higher UV light scanning speeds. Thus, the dimension of the parts obtained at lower UV light scanning speed of 0.018 m/s were found to be higher than the parts obtained at UV light scanning speed of 0.0272 m/s. In addition, due to the oxygen inhibition effect any polymerized solid parts were not obtained at the highest UV light scanning speed of 0.272 m/s from the simulation of the model. Keywords: Photopolymerization, mathematical modeling, stereolithography
Chitosan coating on microcapsule treated fabric and its effect on laundering durability
Get PDFMikrokapsüller, küçük katı partiküllerinin, sıvı damlacıklarının veya sıvı içinde disperge haldeki katıların üzerine mikron mertebesinde ince bir polimer tabakasının kaplanması vasıtasıyla gerçekleştirilen, mikron düzeyindeki bir paketleme tekniği ile üretilirler. Mikrokapsül ihtiva eden kumaşlar, akıllı kumaşlar olarak adlandırılırlar ve kozmetik, terapi, enerji verici, stres azaltıcı, nemlendirici ve konfor özelliği ayrı ayrı veya bazılarını aynı anda beraberce içerebilmektedirler. Mikrokapsüllerin içindeki aktif maddelerin kullanım sırasında çeşitli şekillerde ve zaman içinde yavaş yavaş salınması ile mikrokapsül uygulanmış kumaşlarda amaçlanan aktif maddelerden uzun süre faydalanabilmek mümkün olmaktadır. Mikrokapsüller kumaştaki liflere kullanılan çok özel binderler vasıtasıyla mükemmel bir şekilde bağlanabilmektedir. Bu çalışmada, içinde Myritol 318 (kokonat yağı) ve vitamin E ihtiva eden mikrokapsüller hazırlanmıştır. Fularda emdirme yoluyla, kokonat yağı ve vitamin E içerikli mikrokapsüller %90 poliamid, %10 elastan içeren örme kumaşa tatbik edilmiştir. Üç farklı çapta elde edilen mikrokapsüller, üç farklı reçete ile kumaşa uygulanmıştır. Daha sonra, mikrokapsül tatbik edilmiş kumaş, içerisinde Chitosan laktik asit çözeltisi bulunan fular banyosundan geçirilmiştir. Chitosan çözeltisinden geçirilmiş ve geçirilmemiş mikrokapsül içerikli kumaşlar, elektron mikroskobunda (SEM) ve gazkromotografi altında incelenerek; mikrokapsüllerin yıkama dayanım performansları ve chitosan ile kaplama yapılmış kumaş üzerinde chitosanın yıkama dayanımına olan pozitif etkisi yapılan analizlerin sonuçlarında kendisini göstermiştir. Anahtar Kelimeler: Mikrokapsül, mikrokapsül büyüklüğü, chitosan kaplama, yıkama dayanımı, elektron mikroskobu, gazkromatografik analiz.Micro-encapsulation is a micro-packaging technique which traditionally involved the deposition of thin polymer coatings on small particles of solids, droplets of liquids or dispersions of solids in liquids. Microencapsulated fabrics are among the latest generation of fabrics known as intelligent fabrics, taking into account the functions they perform i.e. cosmetic, with a gradual release of active or volatile micro-capsules for cosmetic, therapeutic, energy-boosting, stress-busting, moisturizing or deodorizing, and, climatic fabrics with phase change microcapsules which are heat-regulating. A direct fragrance application on garment may not show durability to repeated laundering. But one can think of encapsulating those fragrance inside a capsule, which, when touched breaks and releases the active material inside. These microcapsules can be bonded very well with fibers via using some special type of binders. The total process of microencapsulation actually covers three separate processes on a time scale. The first process consists of forming a wall around the core material. The second process involves keeping the core inside the wall material so that it does not release. Also, the wall material must prevent the entrance of undesirable materials that may harm the core. And finally, it is necessary to get the core material out beginning at the right time and at the right rate. Since the beginning of the 90's, trade applications of micro-encapsulation in the textile field have appeared. Textile manufacturers show more and more interest in the textile with durable odour or a cosmetic product which is released by the contact with the skin. Therefore, the numbers of the researches in cosmetic effects of clothing textiles have started to get increased. The main reasons why clothing textiles need cosmetic effects are: Body care (not only face and hand care) is one of the major trends in cosmetics. Textiles cover a large part of the body for most of the day, which means a unique opportunity for the convenient transfer of cosmetics to large parts of the body. Continuous release of small doses of cosmetics may be more effective than single applications of large amounts of well-known drugs. Consumers are increasingly interested in and open to textiles with added effects: functional garments are massive trend in textile. On the other side, cosmetic effects of the clothing textile have been facing with some technical challenges in recent years. The main challenges to attach cosmetic ingredients onto textiles are in such a way that They are not destroyed in the finishing process. They remain stable during storage. They are not washed out during further launderings. They are transferred to the skin while the textiles are being worn and can therefore produce real controllable effects. The main technical challenges are the washing permanency and the controlled release properties. In this study, Myritol 318 (coconut oil) and vitamin E mixtured microcapsules were prepared. By using foulard process, coconut oil/ Vitamin E mixtured microcapsules were applied on 30/1 single jersey fabric (90% Polyamide, 10% Lycra), which is 240 g/sqm. Three different recipes were prepared by using three different microcapsule sizes. Furthermore, microcapsule treated fabric passed through the foulard, which had Chitosan lactic acid solution inside. After that, both Chitosan coated and no Chitosan coated fabric were analyzed under SEM (scanning electron microscopy) and under gas-chromatogram to see its laundering durability performance and the positive effect of Chitosan coating on laundering durability were proved after all these analyses. In this study, it was found out that, as studied with many researchers before, Chitosan played an active role to improve laundering durability by creating a kind of second membrane around microcapsules that are located inside of the fabric. By this way, the membrane shell of the capsules were strengthen with this second layer and the release of the myritol 318 coconut oil were slowed down. Therefore, the microcapsule life could have been extended within the fabric during further home laundering cycles. Creating a kind of second layer around the microcapsule wall decreased the risk of the capsule breakage. Capsules which have thinner membrane are normally much more brittle. Keywords: Microcapsule, microcapsule size, Chitosan coating, laundering durability, scanning electron microscopy and gas-chromatographic analysis
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