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Effects of lead user method on product development performance and a case study
Get PDFEtkili ve güçlü ürün geliştirme, müşteri ihtiyaçlarının doğru olarak analiz edilmesine bağlıdır. Müşteriyi ürün geliştirme proseslerine dâhil eden firmalar, pazarda büyük bir rekabet avantajı elde edeceklerdir. Yeni ürün geliştirme proseslerine müşterinin daha sık dâhil edilmesi, yeni ürünlerin pazara çıkma hızı üzerinde olumlu etkiye sahiptir. Bu bağlamda, pazarların en önemli müşterileri olarak görülen lider kullanıcılar da yeni ürün kavramları ve dizaynları elde etme çalışmalarında, müşteri ihtiyaçlarını analiz etmede önemli ihtiyaç ve çözüm bilgisi sağlarlar. Müşteri ihtiyaçlarının artmasından ve hızlı değişiklik göstermesinden dolayı kilit müşterilerin ürün geliştirme proseslerine dahil edilmesi özellikle otomotiv sektöründe oldukça önemlidir. Bu çalışmada, yeni ürün fikirlerinin üretilmesi prosesine müşterinin dâhil edilmesi, lider kullanıcı kavramı ve metodu ele alınmıştır. Lider kullanıcı metodunun temel uygulama adımları ve bu metodun kullanılmasındaki kritik başarı faktörlerine yer verilmiş ve ürün geliştirme performansı açıklanmıştır. Bu çalışma kapsamında, lider kullanıcıların ürün geliştirme prosesine dahil edilmesinin ürün geliştirme performansı üzerindeki etkilerini incelemek amacıyla otomotiv yan sanayinde faaliyet gösteren 51 firmayı kapsayan bir anket çalışması yapılmıştır. Elde edilen veriler SPSS 11.0 istatistik programı kullanılarak değerlendirilmiştir. Değerlendirme kapsamında; faktör analizi, güvenilirlik analizi, korelasyon ve regresyon analizi yapılmıştır. İstatistiksel analiz bulguları incelendiğinde, ürün geliştirme performansı ile lider kullanıcıların ürün geliştirme prosesinde yer alması değişkeni arasında anlamlı ve pozitif yönde bir ilişkinin olduğu tespit edilmiştir. Anahtar Kelimeler: Lider kullanıcı metodu, ürün geliştirme performansı, faktör analizi, güvenilirlik analizi, korelasyon analizi, regresyon analizi.As a result of increasing competitive pressures together with continuously increasing costumers needs, decreasing production costs and product development times urge companies to adept a systematic product development process. As the product are designed and produced for the costumers, costumer views are vital for the design and it dictates a close collaboration with the costumers. In order to meet their increasing customers’ needs, today many companies are seeking the ways to reflect their costumers’ voices and requirements into their products and services. A product development process based on rapid, non-problematical and costumer voices will provide companies a market success through developed products and services. An effective new product development process depends on the definition of uneasy customer problems. In today’s competitive environment, companies are utilising different methods to define costumers’ needs and to develop products accordingly. Nowadays companies are incorporating the lead users having the abilities to see the general future trends of the market and getting important solutions to these future market needs. In this way, the companies both define the changing costumer needs and getting important competitive advantages by entering their products to the market in shorter times. In this study, firstly the importance of the inclusion of the costumers to the creation of new product development process is outlined, the lead user concept is defined, and the lead user method is explained and the importance of this method in product development studies is underlined. Secondly, the main application steps of the lead user method, namely definition of definition of lead users and lead user characteristics, creation of product concept with lead users and lead users’ product concept test are outlined in detail. Finally, the success factors in the application of this method are examined and the product development performance scales are explained. In the application stage of the work, a theoretical model explaining the effect of inclusion of the lead users into product development process was developed. As a result of continuously improvement of automotive technology and increase in customers’ expectations, the automotive sub-industry has to develop new product and improve the performance of the product they develop. Automotive sub-industry is one of the high value added industries in sustainable, social and economical development of a society and from this perspective it is highly important for Turkey. In this respect, a market survey with a questionnaire in automotive sub-industry was conducted in order to define the effects of lead users considered in the product development process performance independent variable on product development performance dependent variable in the theoretical model. According to the State Statistical Institute (DİE) and Small and Medium Industry Development Organisation (KOSGEB) criterion, 51 out of 210 small and medium sized companies active in automotive sub industry in and around Istanbul and Gebze were responded positively to our questionnaire. 27 of these responded companies were contacted with face-to-face method and 27 of the remaining companies were responded via e-mail. The characteristics of these companies participated in the study are detailed in presented tables. The information gathered from the field survey was analyses with SPSS 11.0 statistical analysis software. In the statistical analysis, it is determined that the dependent and independent variables in the factor analysis are ascertained in the related factors, the scales developed in the reliability analysis are rather reliable. The analysis also revealed that in the correlation analysis there is a meaningful and positive relationship between dependent and independent variables and with the help of simple linear regression analysis it was determined the variable of the inclusion of the lead users in the product development process affects the product development process in high meaningful level and positive manner. Under the light of the current study, the effects of the inclusion of the lead users in the product development process are interpreted from automotive sub-industries perspective. The comments made on this sectoral basis could be considered as a guideline for other companies and the researches. Keywords: Lead user method, product development performance, factor analysis, reliability analysis, correlation analysis, regression analysis
Effect of pore-forming agents on microstructure in La-BaTiO3 ceramics
Get PDFYüksek porozite ve elektriksel direnç, seramik esaslı sensör malzemelerin ana karakteristiklerinden birisi olup sinterleme parametrelerinin değişimi ve La+3 dop etme ile BaTiO3 yapısına söz konusu özellikler kazandırılabilmektedir. BaTiO3 esaslı seramiklerin elektriksel özellikleri, söz konusu seramiklerin çeşitli uygulama alanları ve elektriksel davranışının açıklanmasındaki güçlükler nedeniyle, günümüzde ilgi çekici bir araştırma konusu olmaya devam etmektedir. BaTiO3 esaslı seramiklerde elektriksel direnç, perovskit kafeste baryum veya titanyum konumlarına nadir toprak elementleri dop edilerek etkin şekilde kontrol edilebilmektedir. Porozite yapıcılar ile katkılandırma yönteminin de, sensör uygulamalarında kullanılacak poroz seramiklerin üretiminde etkili bir yöntem olduğu bilinmektedir. Bu çalışmada, grafit ve PMMA (Polimetil metakrilat) katkılarının La+3 katkılı BaTiO3 esaslı seramiklerin porozite özellikleri üzerine etkileri incelenmiştir. Farklı bileşimlerde grafit ve PMMA katkıları içeren örnekler için porozite çalışmaları ve mikroyapısal karakterizasyon yapılmıştır. BaTiO3 esaslı seramiklerde porozite yapıcı katkı türünün porozite ve mikroyapısal özellikler üzerine etkisi incelenmiştir. Buna göre, porozite yapıcı katkılar veya donör katkısının yapıda ikincil bir faz oluşturmadığı belirlenmiştir. PMMA katkısının, grafit katkısına göre daha yüksek porozite yüzdesi ve büyük por boyutları oluşturduğu gözlenmiştir. Grafit katkısı, ekzotermik reaksiyonlar nedeniyle tane büyümesine neden olmuştur ancak tane morfolojisinde belirgin herhangi bir değişim gözlenmemiştir. PMMA ile katkılandırılmış örneklerde ise tane boyutu incelmiştir. Üretilen BaTiO3 esaslı poroz seramiklerin, gaz veya nem sensörü uygulamalarında kullanılmaya elverişli olduğu belirlenmiştir. Anahtar Kelimeler: BaTiO3, porozite, sensör, grafit, PMMA.High porosity and electrical resistance are among the main characteristics of ceramic based sensor materials, which are obtained by the variation of sintering parameters and La+3 doping for BaTiO3. Addition of pore-forming agents (PFA) is also an effective method to fabricate porous ceramics for sensor applications. Several approaches have been done recently for manufacturing porous ceramics. It has been reported that porous BaTiO3 can be prepared by the incorporation of graphite, polyvinylalcohol (PVA), polyvinylbutyral (PVB), borides, silicides, carbides, corn-starch, potato-starch and partially oxidized titanium powder addition to BaTiO3 or by the thermal decomposition of barium titanyl oxalate BaTiO(C2O4)2-4H2O. Oxygen can be adsorbed at the grain boundaries due to the presence of pores in the porous ceramics, which are more favorable to form surface acceptor states compared with ordinary dense ceramics. The addition of organic particles, which vaporize at relatively low temperatures forming small and homogeneously distributed pores, is one of these methods. Porous structures having gas / liquid permeability, which can serve as gas or humidity sensors, could be fabricated via this method. The electrical properties of BaTiO3 based ceramics are still a matter of considerable interest due to their various applications and the difficulty in explaining the electrical behaviour. The electrical resistance of BaTiO3 based ceramics can be controlled effectively by rare earth doping into the barium or titanium sites in the perovskite lattice. In the present study, the effect of low amount of donor doping on the microstructural and electrical properties of BaTiO3 based ceramics was investigated. Instead of applying lower sintering temperatures and/or compaction pressures, using low amounts of additives, BaTiO3-based ceramics were fabricated with sufficient mechanical stability to fit long-term room temperature humidity environment applications. On the other hand, low amount of additives provided the porosity percentages, required for humidity sensing process, which is mainly a surface reaction including the adsorption of water vapour to the ceramic surface. In the present study, the effects of graphite and PMMA (Polymethyl metacrylate) additions on the porosity characteristics of La+3 doped BaTiO3 based ceramics were observed. Porosity and microstructural studies were carried out for PFA containing samples. The effects of the type and PFA content on the porosity and microstructural features of BaTiO3 based ceramics were examined. It was observed that there were not any secondary phases due to the existance of PFAs and donor dopant. PMMA additions caused a more pronounced effect in porosity percent and pore size values than graphite. Donor doping and variable graphite addition concerning BT, BTL and BTLC compositions, did not change the overall microstructural features and grain morphology was similar to BT compositions. However, graphite addition enhanced grain growth due to exothermic reactions. On the other hand, PMMA caused grain refinement. Besides, organic based additive affected the grain morphology and microstructural features. Grain morphology became more homogeneous, regular and globular due to PMMA addition. This result is of great importance from the view that porous ceramics with low density could be manufactured easily by organic addition. SEM images showed that spaces between the pores and intergranular pore morphology was present. Since intergranular pores were connected by larger pores, pore network can be regarded as interconnected spaces forming a type of capillary tube. One of the main advantage of employing additives with low percentages is that it provides economical benefit for the porous ceramics. Stable microstructures related to high temperature processes were obtained by organic addition and porosity requirements were satisfied with homogeneous distribution of high porosity percentages throughout the microstructures of the porous ceramics. The effects of the type of PFA on the porosity and microstructure of BaTiO3 ceramics were examined. It was observed that there is no evolution of a secondary phase due to the existance of PFAs and La+3 dopant. PMMA additions caused a more pronounced effect in porosity and pore size than graphite addition. It was concluded that based on electrical conductivity results, porous BaTiO3 ceramics are effective candidate materials for humidity sensing applications. Keywords: BaTiO3, sensor, porosity, graphite, PMMA
Adsorption mechanism of anionic polyelectrolytes onto kaolin
Get PDFPolielektrolitlerin, önemli bir endüstriyel hammadde olan kaolen mineralinin elektrokinetik özellikleri üzerindeki etkisi ve bu mineral üzerindeki adsorplanma mekanizmasının bilinmesi, başta seramik ve kâğıt yapımı olmak üzere, bu mineralin kullanıldığı birçok endüstriyel alan için büyük önem arz etmektedir. Bu çerçevede, çalışmalarda kullanılmak üzere 3’ü yerli ve 3’ü de ithal olmak üzere toplamda 6 farklı bölgeden değişik özellikte kaolen numuneleri temin edilmiş ve bunlar üzerinde anyonik karakterli 3 farklı polielektrolit (anyonik polilektrolit) kullanılarak elektrokinetik ve adsorpsiyon çalışmaları gerçekleştirilmiştir. Elektrokinetik çalışmalarda, kaolenlerin pH’ya, polielektrolit türü ve konsantrasyonuna bağlı olarak zeta potansiyel ölçümleri gerçekleştirilmiştir. Yapılan ölçümler sonucunda hiçbir kaolen numunesinde, gerek pH’ya ve gerekse de polielektrolit türü ve konsantrasyonuna bağlı olarak sıfır yük noktası tespit edilememiştir. Numunelerin zeta potansiyeli, ölçüm yapılan tüm pH değerlerinde ve polielektrolit konsantrasyonlarında sıfırdan küçük olup, ortam pH’sı ve ortamdaki polielektrolit konsantrasyonu arttıkça zeta potansiyel değerlerinin de mutlak değerce artış gösterdiği saptanmıştır. Adsorpsiyon çalışmalarında ise polilektrolitlerin kaolen alümina sitelerine sterik olarak adsorplandığı ancak adsorplanma miktarlarının kaolen pH’sı, özgül yüzey alanı ve boyut özelliklerine göre farklılıklar gösterdiği tespit edilmiştir. En yüksek polilektrolit adsorpsiyonu yoğunluğu, özgül yüzey alanı en büyük ve pH’sı en düşük olan kaolende, en düşük polielektrolit adsorpsiyonu yoğunluğu ise özgül yüzey alanı en küçük ve pH’sı en büyük olan kaolende gerçekleşmiştir. Anahtar Kelimeler: Polielektrolit, kaolen, zeta potansiyel, adsorpsiyon.Kaolin, a clay mineral and one of the important industrial raw materials, has a broad variety of applications in industry. For example, it is often used in the ceramics, paper coatings, water-based paints and inks and as an additive in polymers. Kaolin crystals consist of alternating layers of silica tetrahedra and alumina octrahedra, the unit cell of the kaolin lattice has the composition [Si2Al2O5(OH)4]. Each kaolin particle consists of a stack of about 50 sheets of twin-layers, held together with hydrogen bonds. The particles are plate-like and the aspect ratio (particle diameter/particle thickness) is about 5–15. There is a significant difference in the chemical composition of the edges and the basal planes of the kaolin particles. There are often crystal imperfections in the kaolin crystals, with ionic substitutions of Al for Si or Mg for Al, which result in an overall deficit of positive charge. This substitution thereby gives rise to a net anionic charge of the basal surfaces of the particles. However, it has been shown that the negative charge of the basal surfaces varies slightly with pH, the origin of this pH-dependent charge could be due to the presence of some amphoteric silanol groups on the basal surfaces. At the edges of the kaolin particles, the octahedral alumina and tetrahedral silica sheets are broken, exposing aluminol and silanol groups which can yield positive charges in acidic solution and negative charges in alkaline solution. The point of zero charge of the edges is around pH 7. Interparticle interactions between the edges and the basal planes of the kaolin particles promote aggregation of the particles into edge-to-edge, edge-to-face or face-to-face structures in concentrated aqueous dispersions. However, adsorption of polyelectrolytes or surfactants on the particle surfaces will change the interactions and thereby alter the colloidal stability and rheological properties of kaolin dispersions. Thus, knowing the effect of polyelectrolytes onto electrokinetic properties of kaolin and their adsorption mechanism is very important especially for production of ceramics and paper. For this purpose, totally six kaolin samples from different deposits, (which are coded as K-730 (Balıkesir-Düvertepe region kaolin), Eti600 (-38m) (İstanbul-Şile region), Ömerli (İstanbul-Şile-Ömerli region), K-2 (a Bulgarian kaolin), CC-31 (an English kaolin) and ESK-410 (an Ukranian kaolin)) and three different polyelectrolytes in anionic character (anionic polyelectrolyte) were supplied for this study. The results of studies can be explained as follows: In experimental studies point of zero charge could not be obtained either by pH values or polyelectrolyte type and concentration for all kaolin samples. The zeta potential of samples for all pH values and polyelectrolyte concentrations was found to be negative, thereby it was observed that increasing the pH value and polyelectrolyte concentration at medium also increased the absolute value of zeta potential. It was also determined that, the surface charge was found to be negative, while the kaolin samples pH is between 4-10 and polyelectrolyte concentration was found to be 10-50 mg/L. The adsorption of anionic polyelectrolytes onto the kaolin surfaces was obtained by steric holding of free anionic poles of polymer chains onto the positive charged kaolin sites and also the pH of medium has an important role for adsorption quantity. Adsorption was found to be decreasing by increasing pH. That was the result of the deduced number of free anionic sites of polyelectrolyte on to the decreasing charged sites on kaolin surfaces and thereby forming lesser electrostatic chain. And also the adsorption of anionic poles of polyelectrolyte onto the basal sites of kaolin (-) was electrostatically impossible. Thus, the highest adsorption density was obtained for Ömerli kaolin at pH value of 4. It was observed that, for kaolin sample coded by CC-31 for which the pH value is about 4, the adsorption quantity of polyelectrolyte was approximately quarter of Ömerli kaolin. This situation originated by the different pH value for each kaolin, and also, the specific surface area and d90 size which were directly according to these parameters. The specific surface areas of Ömerli kaolin and kaolin coded CC-31 were found to be 27.99 m2/g and 12.30 m2/g respectively. Consequently, it was found that the positive sites of Ömerli kaolins were approximately four times of kaolin sample coded by CC-31 according to pH changes in addition to these parameters. Keywords: Polyelectrolyte, kaolin, zeta potential, adsorption
The performance effects by surface treating for worn parts in the glass forming machines
Get PDFYüzey işlemleriyle malzemenin sertlik, süneklik ve yorulma gibi mekanik özellikleri yanında sürtünme ve aşınma, oksidasyon ve korozyona karşı dayanıklılık özellikleri geliştirilmektedir. Sürtünerek çalışan makina elemanlarında belirli bir süre sonra ortaya çıkan aşınma problemlerini azaltmak için birçok yüzey iyileştirme teknikleri uygulanmaktadır. Yaşanan malzeme ve ürün kayıplarını, cam şekillendirme makinalarında minimuma indirmek ve söz konusu bu nedenlerden kaynaklanan duruş ve üretim kayıplarını azaltmak amacı ile gerçekleştirilen bu çalışmada; cam üretim makinalarında kullanılan kalıp kollarının malzemelerine alternatif malzeme ve kaplama türleri denenmiştir. Cam şekillendirme makinalarında mevcut kalıp kolu malzemesi olan AISI 420 kalite çeliğe alternatif olarak seçilen yüzeyi kaplanmış (nitrokarbürleme, sert krom kaplama, akımsız nikel kaplama ve borlama) üç farklı kalitede çelik (AISI 1040, AISI 4140 ve AISI 5140 kalite çelikler) malzeme, kalıp kollarındaki gerçek aşınma şartlarını simule edebilecek şekilde tasarlanan laboratuvar deneyleri için standart numuneler olarak hazırlanmıştır. Hazırlanan numunelere, metal-metal deneyleri yapılarak aşınma davranışları incelenmiştir. Oda sıcaklığında yapılan deneylerde nem ve sıcaklık sabit tutulmuştur. Metal-metal aşınma deneylerinde, pimlere M2 kalite takım çeliği üzerinde aşınma testi uygulanmıştır. Farklı kalitede çelikten imal edilmiş olan kaplanmış taban malzemelerine uygulanan disk üstünde pim deneyi sonucunda kullanılmakta olan sert krom kaplı ve kaplamasız AISI 420 kalite çeliğin bor kaplı AISI 4140 kalite çelik malzemeye göre aşınma oranının sırasıyla yaklaşık 18.67 ve 184 kat daha çok olduğu tespit edilmiştir. Laboratuvar deneylerinin sonucunda AISI 4140 kalite çelik malzeme üzerine borlama ön plana çıkmış ve kalıp kollarının çalışma koşullarında aşınmaya en dayanıklı kaplama ve taban malzemesi olarak borlanmış AISI 4140 kalite çelik kabul edilmiştir. Anahtar Kelimeler: Borlama, cam şekillendirme makineleri, kalıp kolu.The materials science in our country has provided significant developments in recent years. Glass industry has also needed to develop its glass forming machines and their parts for manufacturing the high quality with low price in this competitive environment for being in line with the demands of customers. As a result of this change in the business environment, the selection of materials being used in glass forming machines and the surface treatments applied on these materials have developed in accordance with the technology. Friction, wear, oxidation and corrosion properties of materials can be improved in addition to an increase of the ductility, hardness and fatigue properties of materials by using surface treatement. At glass forming machines, the mechanism which provides the mould to adapt into the glass machine, is called as the arm mould. Although mould and arm mould materials show similar properties, the responsibilities they undertake are totally different from each other. If the expectation from mould material can be described as resistivity to heat and surface roughness at metal glass interface, then the expectation from arm mould can be limited as resistivity to wearing and general suitability to the machine's material. The aim of this study to find an alternative material to the arm mould material as coated or uncoated conditions which are used at the glass forming machines in order to decrease the loss of discarded materials and product at glass machines. As alternatives to the existing arm mould material AISI 420, various kinds of steels (AISI 1040, AISI 4140, AISI 5140) were coated with different kinds of coatings as nitrocarburizing, hard chrome coating, boronizing and electroless nickel coating. To simulate the real working condition of arm moulds at the laboratory conditions, standard specimens are prepared for pin on disc tests. Specimens were at standard of ASTM G99 with a diameter of 4 mm. Specimens and disc are always cleaned at each test and dry friction conditions are provided. During laboratory tests, humidity and room temperature is controlled at %50±5 and 20±2oC respectively. At metal-metal tests, specimens as a pin are fixed on a steel disc with a fixed load where the disc rotates at a constant speed. Tests are applied on M2 steel disc with 0.52 m/s sliding speed, under 5 kg load and at a total sliding distance of 6000 m. Before and after each wear test, the differences at specimens in terms of height (H) and weight (G) are measured with a sensitivity variance of 0.01 mm and 0.1 mg respectively at every 2000 m sliding distance. Steel specimens without any surface treatment have surface hardness values in the range of 170 and 210 HV. After the surface treatment (nitrocarburizing, hard chrome coating and electroless nickel coating) processes, these specimens surface hardness increased up to 800 HV. However, after the boronizing process, specimens surface hardness increased to the higher values up to 1110 - 1495 HV. The results of wear tests are analyzed according to the weight loss of the materials. The relative wear ratio (RWR) is defined as the ratio of the weight loss of a specimen to the weight loss of the reference material, which is defined as the most wear resistant specimen at the wear tests. The most wear resistant material was found as the boronized AISI 4140 steel specimen from the weight loss values. mFrom the results of the pin on disc tests, the specimens weight losses are calculated to identify the relative wear ratio values. Non-coated AISI 420 specimen had the weight loss of 0.0552 gr, hard chrome coated AISI 420 specimen had the weight loss of 0.0056 gr, boronized AISI 4140 specimen had the weight loss of 0.003 gr at 2.000 m sliding distance. From the comprarison of the RWR values of the studied steels, it is found that the boronized AISI 4140 steel is the highest wear resistance material. The RWR values show that the boronized AISI 4140 steel is 18.7 times better than hard chrome coated AISI 420 steel, and 184 times better than uncoated AISI 420 steel in terms of wear resistance. As the results of the wear tests, the boronized AISI 4140 steel is determined as the most wear resistant material in the studied steels and suitable to use as the arm mould material in the glass forming machines. Keywords: Boronizing, glass forming machines, arm mould
Solubility and emulsifying properties of red pepper seed flour and protein
Get PDFProtein, yağ ve lif içeriği oldukça zengin olan kırmızı biber tohumlarının, gıda sanayiinde kullanılarak değerlendirilmesi oldukça önem kazanmaktadır. Kırmızı biber tohum unu ve proteininin çözünürlük ve emülsiyon özellikleri, ticari ürün olan soya protein konsantresi ile karşılaştırılarak incelenmiştir. Bu amaçla yağı alınmış kırmızı biber tohum unu hazırlanmış ve bu undan ekstraksiyon ve izolasyon metodu ile protein elde edilmiştir. Kırmızı biber tohum proteini için en düşük çözünürlük değeri pH 4’de elde edilmiş ve bu değerin altındaki ve üstündeki pH değerlerinde çözünürlük artmıştır. Kırmızı biber tohum proteini, alkali koşullarda kırmızı biber tohum unu ve soya protein konsantresinden daha yüksek çözünürlüğe sahiptir. Genel olarak tüm örneklerde tuz konsantrasyonu arttıkça çözünürlük de artmaktadır. Kırmızı biber tohum proteininde tuz konsantrasyonun çözünürlüğe olan etkisi kırmızı biber tohum ununa göre daha fazladır. Kırmızı biber tohum unu ve proteinin emülsiyon aktivitesi değerleri sırasıyla %49.3-54.7 ve %48.8-70.4; emülsiyon stabilitesi ise %52.9-54.33 ve %47.19-64.9 aralığında değişmektedir. Kırmızı biber tohum proteinin, emülsiyon özellikleri proteinlerin çözünürlük eğrileri ile paralellik göstermektedir. Kırmızı biber tohum proteini, bazik pH koşullarında kırmızı biber tohum ununa ve soya protein konsantresine göre daha yüksek emülsiyon özelliklerine sahiptir. Kırmızı biber tohum proteini ile oluşturulan emülsiyonun stabilitesi kırmızı biber tohum unu ile oluşturulana göre daha yüksektir. Kırmızı biber tohum proteinin emülsiyon özellikleri tuz ilavesi ile azalırken, kırmızı biber tohum unu ve soya protein konsantresinin emülsiyon özellikleri değişmemektedir. Anahtar Kelimeler: Kırmızı biber, emülsiyon, çözünürlük, protein.Recently more attention has been focused on the utilization of food processing by-products and wastes. Obviously, such utilization would result in the production of various new products for food and contribute these products into foods. Only a small portion of plant material is utilized directly for human consumption. The remaining portion of this material or part of it may be converted into nutrients for either food or feed or into fertilizer. Peppers belong to the genus Capsicum, where C. annuum L. is the most widely cultivated species. They are grown mainly for its fruit although the seeds could also be used as spice after drying and grinding. They are processed into dehydrated products, pickled peppers, and sliced or diced frozen peppers or into products such as sauce, paste, puree and powder for flavoring or coloring purposes and many more. Red pepper seeds are excellent sources of protein, oil and fiber and they are rich in total essential amino acids, lysine, threonine, total aromatic amino acids, and tryptophan. Among the pepper producing countries, Turkey ranks the third after China and Mexico with 1,745,000 tons of produce per year. Utilization or the disposal of solid wastes remaining after canned/frozen pepper products processing that consist of stems, leaves and seeds are the most challenging tasks for the industry. Proteins, as isolates or concentrates, are necessary ingredients in many food processes where they perform specific functions. Functional properties of proteins can be defined as physicochemical properties which affects the behaviour of proteins and contribute to the food quality and sensory properties during food preparation, processing, storage and consuming. Proteins change the physical properties of food by interacting with solvent, ions, other proteins, polysaccharides, lipids inside the surrounding environment. Properties such as solubility, water holding capacity, lipid binding property, foam capacity and stability, emulsion capacity and stability and gel formation of protein are the functional properties that affect the food quality. Emulsifying properties are important functionality traits related to the protein used in food products. Emulsifying capacity and emulsion stability are usually used to investigate the emulsifying properties of proteins in food emulsion systems. Various factors and conditions affect emulsifying properties of proteins including source of protein, protein concentration, pH, solubility, temperature, equipment and the method used to produce the emulsion. Solubility plays a role in emulsifying properties of proteins. Highly in soluble proteins display very poor emulsifying properties. In this study, emulsifying properties of red pepper seed flour and protein were monitored in relation to influence of pH and concentration. It is hoped that the data will provide information on utilizing red pepper seed flour in various food applications. The red pepper seed consists of 9.30% moisture, 19.32% fat, 23.64% protein, 3.55% ash, and 48.98% carbohydrate in dry basis. It is highly possible to use it as good source of protein and diet fiber due to its content of high protein and diet fiber. The protein concentration obtained from red pepper seed contains 6.63% moisture, 1.52% fat, 67.00% protein, 4.59% ash, and 26.87% carbohydrate. Red pepper seed protein concentrate contains more protein than soy protein concentrate, which is a commercial product. In alkaline conditions, red pepper seed protein showed a higher solubility than red pepper flour and soy protein concentrate. Generally, solubility increased with increasing salt concentrations in all samples. The effect salt concentration on red pepper seed protein was higher than red pepper seed flour. After this concentration, no change was observed. Emulsion activity of red pepper seed flour and protein was 49.3-54.7% and 48.8-70.4%, respectively. And also emulsion stability was 52.9-54.3% and 47.2-64.9%, respectively. The emulsion properties of red pepper seed protein showed similar trend with solubility curves. Red pepper seed protein had higher emulsion properties than red pepper seed flour in alkaline conditions. The emulsion prepared by red pepper seed protein was more stable than prepared by red pepper seed flour. The emulsion properties of red pepper seed protein decreased with salt addition. On the other hand, the emulsion properties of red pepper seed flour and soy protein concentrate were not affected by salt addition. Keywords: Red pepper seed, protein, emulsifying properties, solubility
Modelling of disodium octaborate drying in a spray dryer
Get PDFStokiometrik oranlarda borik asit ve borakstan hazırlanan çözeltiden suyun püskürtmeli kurutucuda uzaklaştırılması ile üretilen hidrate disodyum oktoboratın kuruma davranışının belirlenmesi için gerçekleştirilen matematiksel modelleme çalışmalarında en az varsayımın yapıldığı en üst düzey kabul edilen hesaplamalı akışkanlar dinamiği modeli uygulanmıştır. Modellemede, sürekli faza ait kütle, momentum ve enerji korunum eşitlikleri ile dispers faza ait temel korunum eşitlikleri ve türbülans büyüklüklerini içeren diferansiyel denklem setlerinin çözümü için sonlu hacimler metodu ile çalışan STAR-CD yazılımı kullanılmıştır. Damlacıkların kurutulması esnasında aynı anda iki süreç gerçekleşmektedir. Bunlardan birincisi damlacıklara dışarıdan transfer edilen enerji ile yüzeydeki suyun hava akımı içerisine buharlaştırılması, ikinci süreç ise suyun yüzeyden buharlaşmaya başlaması ile aynı zamanda damlacığın iç kısımlarındaki nemin sıvı veya buhar halinde yüzeye transferidir. Partikül içerisindeki nem taşınımı kararsız hal difüzyon eşitliği ile ifade edilerek, lokal nem içeriği ve sıcaklığa bağlı difüzyon katsayısı hesaplanmış literatürden elde edilen matematiksel eşitliğe uyarlanmıştır. Ayrıca, iki farklı sıcaklıkta ve bağıl nem 0.1 – 0.9 aralığında su buharı desorpsiyon izotermleri oluşturularak denge nem oranları hesaplanmıştır. Difüzyon eşitliğine ait katsayılar, damlacık boyut dağılımı, damlacıkların ilk hızları, türbülans model katsayıları, kurutma havası ve besleme çözeltisi özellikleri yazılımın ön işlemcisinde tanımlanarak, kurutucu içerisinde sürekli faza ait hız, yörünge, sıcaklık ve nem değerleri ile dispers fazda, damlacık kuruma hızları ve kurutucuda kalma süreleri belirlenmiştir. Püskürtmeli kurutucunın üç seviyesinde her seviye için altı noktada nem ve sıcaklık değerleri ölçülerek, elde edilen model sonuçları ile deneysel ölçümler karşılaştırılmış, model sonuçları ile deney sonuçlarının birbirine uyum gösterdiği saptanmıştır. Anahtar Kelimeler: Püskürtmeli kurutma, hesaplamalı akışkanlar dinamiği, disodyum oktaborat.Spray drying is one-step continuous unit processing operation for transformation of feed from a liquid form to a dry powder. The feedstock prepared by aqueous solution of borax and boric acid mixtures was atomized into a drying chamber where the resulting spray mixes with hot gas, which evaporates the liquid component of the droplets. The spray dried powders have the appropriate composition of disodium octaborate tetrahydrate. A computational fluid dynamic study was carried out to investigate airflow pattern, temperature, and humidity profile at different levels in the drying chamber. The effects of operating and boundary conditions on the gas flow pattern, droplet trajectories, and overall dryer performance also were investigated. Results are presented and discussed in terms of the gas velocity, temperature, and humidity profiles within the chambers. The analysis were performed on spray dryer fitted with rotary atomizer using STAR-CD code by Euler Lagrange approaches in which the conservation equations of mass, momentum and energy for the gas flow in the dryer are expressed in the Eulerian form and the droplets in the Lagrangian. In the case of turbulent flow, the conservation equations were solved to obtain time averaged equations. Additional terms in these equations represent the transport of momentum, heat and mass solved by RNG k turbulence model. The droplets temperature, mass and velocity were determined at every location of their trajectories from the local time-averaged solution for the gas. In order to describe the internal mass transfer, one-dimensional diffusion equation was solved to model the internal distribution and diffusion of water moisture inside the particle which is assumed as spherical shaped. The diffusion coefficient was determined as function of moisture content and temperature. The partial water pressure at the droplet surface is related to the surface moisture content and droplet temperature by desorption isotherms which mathematically represented with three-parameter Guggenheim -Anderson - De Boer (GAB) equation that represents a kinetic model based on multilayer and condensation. Atomization from a rotating disc was modeled by putting 100 injection points along the peripheral of the size of the atomizer. The total feed rate was distributed evenly between the injection points. For each injection, the initial droplet size distribution was back calculated from the size of particles collected from the drying experiments. This back-calculation method assumes uniform shrinkage of the droplet and that there is no inhibition to shrinkage due to the sudden reduction in moisture. In actual condition, depending on the operating parameters, a crust may form from the sudden initial removal of moisture, preventing further shrinkage of the droplet. Since such mechanism is difficult to quantify in an actual dryer, the shrinkage model used as a simplifying assumption. The volume of product changes with the moisture content can be calculated from the actual density of the product and actual particle weight. For carrying out a simulation, first of all the geometry of the dryer was required to be able to make the mesh for the CFD calculations. A calculation grid of the drying chamber was generated with the help of the grid generator. During the calculations the CFD model interacts with the material property database. The gas flow solver calculates the gas conditions, such as temperature, moisture, velocity and degree of turbulence, in each cell of the grid. The particle tracker reads in these data in order to calculate the trajectories and the drying behavior. When the particles pass a cell of the grid the amounts of energy, mass and momentum transferred to the gas are calculated. In the next iteration program uses these transfer terms for a new calculation. The calculation loop is repeated until sufficient convergence is achieved. Accuracy of the drying models is largely affected by the prediction of the airflow within patterns in the drying chamber. The coupling effects from the transfer of mass and energy through the droplet-air interface which will further affect the properties of the air. A simple case study was used to illustrate the ability of CFD in performing optimization analysis. The model was validated by experimental tests on a pilot scale dryer on the base of temperature and water vapor concentration field measurements. The results showed that, this model is potentially usable for spray dryer chamber design for optimization, deposit prevention and scale up. Keywords: Spray drying, computational fluid dynamics, disodium octaborate
An investigation on the energy efficiency of refrigerator, effect of gasket and flange heater
Get PDFBuzdolaplarının enerji tüketim değerini etkileyen temel parametreler soğutma ve yalıtım sistemidir. Conta ve flanş bölgesi buzdolabı yalıtım sisteminde önemli bir yer tutmaktadır. Özellikle yalıtım malzemesinin iyileştirilmesi ile etki oranı artış göstermektedir. Bu çalışmada temel olarak, buzdolaplarında terleme ve conta yapışmasının önüne geçilebilmesi amacıyla kullanılan flanş ısıtıcılarının ve contanın buzdolabı ısı kazancına etkisi, sayısal ve deneysel olarak incelenmiş; flanş ısıtıcısı ve conta bölgesinden gerçekleşen ısı transferi belirlenmiştir. Çalışmanın iki ana kısmından ilkini oluşturan deneysel çalışmalar yardımı ile öncelikli olarak mevcut durumda conta ve flanş bölgesinden gerçekleşen ısı transferi belirlenmiştir. Deneyler sonucunda elde edilen değerler literatür değerleri ile karşılaştırılmıştır. Çalışmanın devamında bu bölgeye uygulanabilecek geometriler belirlenerek uygulanmış ve bu uygulamaların buzdolabı enerji tüketimine etkisi araştırılmıştır. İkinci adımda sayısal çalışmalar gerçekleştirilmiş, öncelikle mevcuttan daha basit bir geometri ile flanş ısıtıcısı uygulaması için sayısal bir model oluşturulmuş ve bu bölgenin analizi mevcut durum için gerçekleştirilmiştir. Bu model ile elde edilen sonuçlar çerçevesinde buzdolabı gerçek modeli oluşturularak IDEAS programında analizler mevcut ve farklı uygulamalar için gerçekleştirilmiştir. Farklı uygulamalar, flanş ısıtıcısının konumunun değiştirilmesi, boru malzemesinin ve geometrisinin değiştirilmesi olarak tanımlanmıştır. Analizlerden elde edilen uygun sonuçlar buzdolaplarına uygulanmış ve deneysel olarak irdelenmiştir. Yapılan deneylerin sonuçları, bu bölgede terleme ile contanın yapışmasını engelleyebilen, ek olarak flanş ısıtıcısından kabin içerisine geçen ısı miktarını da azaltabilen bir uygulama ortaya koymuştur. Anahtar Kelimeler: Buzdolabı, conta, sayısal analiz.Main parameters, which affect the refrigerator energy efficency, are cooling system and insulation system. The perfomance of the insulation system is directly affected by the performance of the insulation material. The effects of the gasket and the flange heater on the insulation performance are high. Espicially by using efficient insulation material the effect will be higher. The gasket and flange region consists of flange heater, gasket itself and the insulation system. For the heat transfer from the gasket, the infiltration rate from the gasket should be considered, too. Flange heater can be used in the cooling system or as a seperate electrical heater, which is called anti sweat heater. Generally the anti swaet heater is located in the mulllion region in the refrigerator.As mentioned earlier, the flange heater can be used in the cooling system. It works with the compressor and is normally used to prevent the perspiration in refrigerators and gasket adhesion. For hard conditions, like high temperature or high relative humidity values, the flange heater is located after the compressor in the cooling system. For normal conditions, like for example for 25 °C environmental temperature, the flange heater is located after the condenser in the cooling system. In this study, the effect of flange heaters, which can be located before or after condenser in the cooling system of the refrigerator, and gasket on the refrigerator heat gain have been investigated numerically and experimentally in order to prevent the perspiration in refrigerators and gasket adhesion and the heat transfer through flange heaters and gasket zone is identified.In the first part of the study, the heat transfer through flange heaters and gasket zone and the effect of gasket and flange heater in the current situation are studied separately. Additionally, gasket infiltration effect is defined with the help of the experimental work. The derived results are compared with the literature values. Consecutively, the alternative geometries that are appropriate for this zone are determined and applied. Then, the effect of these applications on refrigerator energy consumption is investigated. In the second part, numerical research is carried out. Accordingly, a numerical model is formed with a simpler geometry than the present one, solely for the flange heater application and with the help of the model, this zone is analysed for the current situation.Results from the basic model gave the beginning conditions for the actual model simulation. In the framework of the positive results derived from this model, the actual model of the refrigerator is generated and analysis performed with IDEAS software for both the current and alternative applications. Analysis was carried out for two dimensional steady state conditions. Boundary conditions for the analysis were selected from experimental results and theoretical formulations. As the alternative applications, altering the place of the flange heater in insulation volume, changing the material of the flange heater and changing the geometry of the heater are tested. Following the performed analysis, the appropriate results are applied on refrigerators and experimental verification tests are conducted. Tests, which were made for the verification showed that the location of the flange heater should be changed in order to get lower temperatures and lower heat transfer from the flange heater to the cabinet. Additionally, the geometry of the flange heater was investigated for getting lower temperatures inside the cabinet. Results of the analysis showed that the actual geometry is the best application compared with the alternative geometries. The material of the flange heater is one of the important parameters, which affect the heat transfer from the flange heater to the cabinet. Copper was used as the flange heater material instead of stainless steel material and results of the analysis showed no difference between two materials for heat transfer, but for the application copper flange heater is a good alternative to the stainless steel flange heater because of easy handling. As an outcome of the study, an application that is capable of preventing the perspiration in gasket and flange zone and additionally reduce the amount of heat transferred from the flange heater into the cabinet has been put forward. Keywords: Refrigerator, gasket, numerical solution
Styrenation of triglyceride oil through controlled / living free radical polymerization
Get PDFBu çalışmada, kontrollü/yaşayan radikal polimerizasyon tekniklerinden biri olan tersinir katılma –bölüşme zincir transfer polimerizasyon (reversible addition – fragmentation chain transfer polymerization - RAFT) tekniği kullanılarak hava üflenmiş keten yağının stirenlenmesi gerçekleştirilmiştir. RAFT ajanı (Zincir transfer ajanı) olarak Fenasil Morfolin Ditiokarbamat (PMDC) kullanılmıştır ve polimerizasyonda uygun miktarı belirlenmiştir. RAFT ajanı miktarı, peroksit gruplarının oluşturacağı serbest radikaller esas alınarak hesaplanmıştır. Polimerizasyonda, değişen miktarlarda PMDC kullanılarak, miktarın ürün özellikleri üzerine etkisi incelenmiştir. Elde edilen sonuçlara göre, ortamda oluşan serbest radikallere ekivalent miktarda PMDC kullanıldığında polimerizasyonun kontrol edilebildiği ve dar molekül ağırlığı dağılımının sağlandığı görülmüştür. Ekivalent miktardan daha fazla PMDC kullanıldığında ise polidispersitenin daha da düştüğü gözlenmiştir. Elde edilen stirenlenmiş yağ örnekleri GPC ve FT-IR analizleri ile karakterize edilmiştir. Sonuç olarak RAFT polimerizasyon tekniği kullanılarak, polidispersitesi düşük (<1.5) ürünler elde edilmiştir. Bu yöntem ile elde edilen ürünlerin, klasik yöntemin tersine, homopolimer içermedikleri çapraz bağlı filmler üzerinden yapılan test ile anlaşılmıştır. Ayrıca elde edilen ürünlerin film özellikleri, ilgili standartlara göre incelenmiş ve klasik yöntem ile elde edilen ürünün film özellikleri ile karşılaştırılmıştır. Karşılaştırma sonucunda, RAFT tekniği kullanılarak elde edilen ürünlerin, klasik yöntem ile üretilene göre suya ve baza karşı daha dayanıklı oldukları ve kuruma süresinin daha kısa olduğu görülmüştür. Filmin daha kısa sürede kuruması yüzey kaplama endüstrisinde istenilen bir özelliktir. Ayrıca bu ürünlerin yapışma özelliği de klasik yöntem örneğine göre daha iyi çıkmıştır. Anahtar Kelimeler: Stirenlenmiş yağ, kontrollü/yaşayan polimerizasyon, RAFT.Triglyceride oils owe their value as raw materials for decorative and protective coatings to their ability to polymerize and cross-link or dry after they have been applied to a surface, to form tough, adherent films. In order to obtain coating material having better performance in industry, oils are modified with various methods. Among these modified methods, copolymerization of oils with vinyl monomers such as styrene occupies an important place. In the classical styrenation process, homopolystyrene formation is likely to occur. The formation of homopolystyrene is not favor in product since the presence of homopolymer leads to weak film properties. By taking this fact into account, the methods by which homopolymerization was minimized and polymer structure was controlled, were previously developed in our laboratory. As a continuation of these studies, in this study, in order to obtain styrenated oil, air blowing linseed oil was copolymerized with styrene by the controlled / living radical polymerization technique (CLRP). CLRP is particularly appealing as it not only delivers polymers having a narrow molecular weight distribution with predetermined average molecular weight but also can be performed using normal radical procedures without the stringent experimental conditions required in living ionic polymerization. The most widely used controlled radical polymerization techniques are reversible addition fragmentation chain transfer polymerization (RAFT), nitroxide mediated polymerization (NMRP) and atom transfer radical polymerization (ATRP). Among of these techniques, the RAFT polymerization has been considered a the most versatile and robust method, since it can be compatible with almost all monomers and reactions conditions that are applicable to conventional free radical polymerization. The RAFT process and its benefits are achieved simply by the addition of a suitable RAFT agent to the reaction medium. In this work, styrenated oil was obtained in three step. In the first step, the air was passed out through preheated linseed oil for 18 hours at 80 0C, thus, the peroxide groups on the oil triglyceride molecules created. Polymerization of oils is provided due to free radicals resulting in their decomposition. Peroxide value of oil was determined as 485 meq peroxide - oxygen/kg oil. In the second step, phenacyl morpholine dithiocarbamate (PMDC) was prepared in laboratory and used as RAFT agent, R and Z being phenacyl and morpholine, respectively. The structures of R and Z of the RAFT agent would exist in the chain ends of the final polymers. Thus, the end group of the polymer can be predesigned by choosing the RAFT agent with the desired structures. In the third step, air blown linseed oil was styrenated in the presence of PMDC under nitrogen atmosphere at 90 0 C. Temperature was kept constant with controlled heating. In order to investigate the effect of the RAFT agent amount on the copolymer, different amounts of the RAFT agent were used in the reaction. The characteristic properties of the samples such as molecular weight, polydispersity and molecular structure were determined by Gel Permeation Chromatography (GPC). The results show that, in the RAFT polymerization technique, when RAFT agent was used in the equivalent amount to the free radicals, products with low polydispersity were obtained while without homopolystyrene formation. Also when the amount of RAFT agent was excess than that of the equivalent to the free radicals, polydispersity became lower. In addition to these, polymer with higher molecular weight and higher conversion were obtained with increasing reaction time and polydispersity was still at low level. For all that, three peaks were observed in GPC chromatograms. This is the expected result since the hydroperoxides decompose to give free radicals under blowing conditions. As a result this fact, chain propagation by coupling and abstraction reactions cause different molecular weight and ultimately leads to deviation from the unimodel shape. Besides, the oil-styrene copolymer structure was assigned by means of FT - IR measurements. The FT - IR spectrum of styrenated oil showed the characteristic bands of both styrene and initial oil segment. The film properties of the resulting sample was determined according to related standards as well. Copolymer of the oil with styrene was also prepared by conventional method and this sample were used as a comparative sample. The sample obtained with RAFT polymerization technique showed better alkali and water resistance and better adhesion and the shorter drying time than the classical sample which obtained in the absence of the RAFT agent.. Keywords: Styrenated oil, controlled/living polymerization, RAFT
Concept in design process
Get PDFBu çalışmayı, tasarım sürecinde bilişsel yeti olarak kavramın, tasarım stüdyosu öğrencileri üzerindeki etkisini anlayabilmek amacıyla yapılan görgül (ampirik) bir araştırma oluşturmaktadır. Sınanan iki hipotez: 1. Tasarıma kavramla ya da tasarım öncesi biçimle başlayan öğrenciler, tasarımı daha kolay geliştirebilmekte ve tasarıma kavramla başlamayanlara göre daha başarılı olmaktadır. 2. Tasarımcının kendisinin türettiği kavram ve tasarım öncesi biçimler, tasarımcıya başkası tarafından verilenden daha başarılı olmaktadır. Olağan stüdyo işleyişini hiç değiştirmeden ve öğrencilerin haberi olmadan yapılan bu çalışmadan amaç, tasarımın başlangıcından sonuna değin öğrencinin tasarım için bir kavram ya da ana düşünceyle çalışıp çalışmadığına bakmak ve bunun son ürünün değerlendirmesiyle bir bağlılaşımı olup olmadığını görebilmektir. Sınanan iki hipotez de istatistiksel olarak doğrulanmıştır.An empirical research, which looks into the correlation between concept as a cognitive faculty and the success of the design among architecture and interior architecture design students, constitutes this study. The two hypotheses, tested, are: 1. Those who start the design process with a concept or a pre-design form are able to develop the design easier and are more successful than those who start without a concept or a pre-design form. 2. Concept or the pre-design form that is generated by the designer is more successful than those that are given to the designer.Without changing or interfering with the usual studio operations and without letting the students know about it, the empirical study has been intended to see whether the design students start the design process with a concept or a main idea and develop their design accordingly, and whether there is a correlation, if any, between how they proceed with the design and the evaluation of the final design product. The study, conducted among 207 design students over a two semester period, and the results of the statistical analysis support the hypotheses
Investigating design: forty years of design research
Get PDFTasarım araştırmasının ne anlama geldiğini tanımlayarak başlayan bu makalede son kırk yılda tasarım araştırmalarındaki gelişmeler ele alınmaktadır. Özellikle önce tasarlama metotları ve tasarım araştırmaları arasındaki ilişkiler ve paralel gelişmeler açıklanmaktadır. Tasarlama metotlarında birinci ve ikinci nesil olarak adlandırılan paradigma değişiklikleri ve tasarım araştırmaları ile bu paradigmaların ilişkileri üzerinde durulmaktadır. Daha sonra tasarım bilimindeki gelişmelerin bugünkü tasarım araştırmalarına yansıması irdelenmektedir. Üniversitelerde son kırk yılda yapılan kongreler, devlet kuruluşlarında yapılan önemli araştırmalar, ulusal ve uluslar arası tasarım araştırmalarına ilişkin kuruluşların oluşumu ve son yirmi yıldaki tasarım araştırmalarının yönelimleri bugünkü araştırma yaklaşımlarında farklı disiplinlerde yapılan araştırmaların rolü açıklanmaktadır.Objective of this paper is to investigate the developments of design research in the last forty years after II World War. The paper begins with the extensive definition of design research and tries to show what is not accepted as design research, and what is assumed to be design research. Especially the parallel developments of design methodology and design research are reviewed giving examples from architecture and engineering disciplines. The advancements in design methodology and paradigm shifts in design methodology, the first- and second-generation design methods and the place of design research in these early years are explained with reference to the major criticisms of the leading people of the era. The roles of second-generation design methods are explained with their pitfalls. Developments in the design science and its consequences on design research are explained in relation to architecture as well as engineering. The role of research approaches in various disciplines such as architecture, engineering, computer aided design, social psychology, ergonomics, etc on the present design research is explained with reference to the conferences organized by the universities in the last forty years, the significant research works in government organizations, and national or international organizations. Suggestions are made in the concluding remarks that many lessons can be learned from the neighboring discipline such as architecture and engineering
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