IYTE GCRIS Database (Izmir Institute of Technology)
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The Effect of Starch Types on Extensional, Linear and Nonlinear Rheological Properties of Starch Cracker Dough
No full textCracker is a popular snack, and their quality depends on the rheological properties of the dough during production. This study focused on the impact of different starch types (tapioca, corn, and potato) used in the same amount (30 g) on the rheology of starch cracker dough. Various rheological tests were conducted to assess the dough's properties. Linear viscoelastic properties were determined using oscillatory frequency and temperature sweep tests, while the nonlinear viscoelastic behavior was characterized through stress relaxation and creep recovery tests. Extensional rheological behavior was also examined. Additionally, the textural and thermal properties of the dough were monitored to understand starch gelatinization and its interactions with other components. In the linear viscoelastic region, no significant differences were found between different dough formulations. However, in the nonlinear viscoelastic region, the potato starch-containing formulation exhibited different viscoelastic and textural properties. Biaxial extensional rheological behaviors showed no significant variations between formulations. The temperature sweep test data from differential scanning calorimetry measurements were consistent with temperature sweep data. In summary, this study provides valuable insights into how different starches influence the rheological behavior of starch cracker dough, considering various degrees of deformation and temperature. These findings have implications for cracker production parameters
Spatial Analysis of Regional Income Inequality in Eu Countries
No full textThis article analyses regional convergence and the diminishing regional disparities within the EU27 from 2000 to 2019. It assesses the impact of income fluctuations on regional inequality by employing secondary analysis of income per capita indicators across NUTS 3 level regions. The article provides a quantitative assessment of regional income inequality, encompassing the most prevalent instruments used in the analysis of inequality data. In particular, it determines EU regional disparities using constructed Theil, Gini and CV indices exposing a more comprehensive evaluation of regional disparities within the EU. It also examines the nexus between spatial effects on regional income inequality. The findings suggest that EU convergence persists at the NUTS 3 level, albeit at a decelerating pace. We also point to the role of clustering effects among neighbouring regions. Notably, the study highlights the diminishing role of regional clustering due to income inequality during the ongoing convergence process
Gyroıd Yapısının Gözenekli Ortam Olarak Akış ve Isı Transfer Performansının İncelenmesi
No full textIsı transferini iyileştirmek için aktif ve pasif yöntemler kullanılmaktadır. Pasif yöntemlerden biri yüksek ısı transfer yüzey alanına sahip gözenekli ortamlardır. Gözenekli ortamlar düzenli ve düzensiz yapılar olmak üzere iki gruba ayrılır. Düzenli yapılardan biri de son zamanlarda oldukça sık incelenen üç yönlü periyodik minimal yüzeylerdir (ÜYPMY). Bu çalışmada, literatürde en çok kullanılan ÜYPMY'lerden biri olan Gyroid geometrisinin ısı transferi ve akış analizi, eşlenik ısı transferi koşulları dikkate alınarak sayısal olarak incelenmiştir. Tek bir gözeneklilik dikkate alınmış (ε = 0,6) ve ısı değiştiricideki sıcaklık değişimini incelemek için ısı değiştirici malzemesi olarak alüminyum, seramik ve PLA seçilmiştir. Farklı akış koşullarını değerlendirebilmek için Reynolds sayıları (Reh) 19,12 - 95,61 ve 172,09 olarak kabul edilmiştir. Akışkan giriş sıcaklığının 298,15 K'da sabit olduğu, ısı değiştiricinin başlangıç sıcaklığının ise havalandırma standartlarındaki rejeneratif ısı geri kazanım sıcaklık farkıyla tutarlı olması için 278,15 K'de sabit olduğu varsayılmıştır. Farklı çalışma koşullarındaki Nu sayıları karşılaştırıldığında, düşük ısıl iletkenliğine rağmen düşük ısıl yayılımı en yüksek seviyede olan seramik malzemedir. En yüksek Re sayısında alüminyum eşanjöre göre yaklaşık %6 daha iyi ısı transferi sağlamıştır
Modification of Pea Protein Isolates by High-Intensity Ultrasonication: Functional, Structural and Nutritional Properties
No full textThe current study aims to modify the functional, physical, structural and nutritional characteristics of pea protein isolate. High-intensity ultrasound treatment was used at 20 kHz frequency and 25 % amplitude for 10 (US10), 20 (US20), or 30 (US30) min. Results indicated that ultrasound application enhanced the protein solubility and zeta potential. When compared to control samples, the foaming capacity (FC) and stability (FS) as well as emulsion activity (EA) and stability (ES) were also increased from 157.5, 42.03, 46.25 and 53.75 % up to 182.5, 81.57, 72.50 and 67.50 %, respectively. Besides, particle size was found to be lower for ultrasound treated samples (92.9–131.1 nm) in comparison to that of untreated commercial pea protein isolate (161.9 nm). Moreover, while the bioaccessibility of pea protein in untreated sample was calculated as 28.90 %, ultrasonication increased the retention of pea protein up to 49.36 %. It can be concluded from the results that the ultrasonication process can be used as an advantageous, green and non-thermal tool for obtaining protein isolates with improved techno-functional properties and nutritional quality. Therefore, this treatment might improve the characteristics, and thus increase the utilization of plant-based proteins, especially pea protein, in various food systems. © 202
Concurrent Boron Removal From Reverse Osmosis Concentrate and Energy Production Using a Microbial Desalination Cell-Donnan Dialysis Hybrid System
No full textThe removal of boron from aqueous solutions offers an important opportunity to improve the management of sustainable resources. In this regard, microbial desalination cells (MDCs) are a promising bioelectrochemical approach for effective water treatment, but the integrated MDC-Donnan Dialysis (DD) process for boron removal from reverse osmosis (RO) concentrated effluents has not been investigated before. Integration of the DD process with MDC is investigated in this paper for the first time to enhance the efficiency of the process by providing pre-treatment and natural pH manipulation. Therefore, the MDC process was evaluated for boron removal from boron-containing synthetic solution, geothermal water, and RO-concentrated effluent with the help of the DD system. The highest boron removal performance, with an efficiency of 72.1% in the desalination chamber and 74.8% in the DD-feed chamber, was obtained for boron-containing synthetic solution, while the COD removal efficiency was almost 90% in all water resources. However, the maximum power density was 4818 mW m-2 with a closed circuit voltage of 1317 mV for RO concentrated water treatment due to its high ionic strength. Moreover, the most crucial output of this study is that the pH value of the system did not need to be adjusted continuously to convert the uncharged boric acid into the borate ion in the charged form owing to better manipulation of the pH by the DD system. Overall, the integrated MDC-DD system provided promising results, presenting effective boron-containing water desalination, yeast wastewater treatment, and enhanced energy production
Localizing Implicit Gradient Damage Based Modelling of Quasi-Brittle Failure With Non-Planar Crack
No full textLocalizing implicit gradient damage (LIGD) is a gradient extended model which is equipped with a decreasing internal length scale with damage evolution, Poh and Sun (2017). The model is thermodynamically consistent and resolves the well-known problems of conventional implicit gradient damage (CIGD) model such as artificial diffusion of damage and erroneous predictions of failure initiation and propagation directions. So far, the effectiveness of the model has been demonstrated for two-dimensional quasi-brittle and three-dimensional ductile failure predictions with flat fracture surfaces. It is the aim of this contribution to assess the predictive capabilities of the model for three-dimensional quasi-brittle failures with non-planar cracks. To this end, localizing implicit gradient model is embedded within a tetrahedral element formulation and implemented in commercial finite element package Abaqus through user element (UEL) subroutine. Skew notched prismatic torsion test is modeled and capabilities of the model are assessed in terms of reaction force-displacement curves as well as the resulting crack surfaces, Brokenshire (1996), Jefferson et al. (2004). Comparison of LIGD and CIGD predictions suggest that LIGD is superior to CIGD. Furthermore, as far as capturing the experimental results is concerned, it performs as good as other alternative modeling frameworks, e.g., mixed finite element formulations. © 2024 The Author(s)
Carcass Trait, Meat Lipid Profile and Meat Quality of Broiler Chickens Fed Diets Containing High Inclusion Level of High Quality Cassava (Manihot Esculenta) Peel Meal
No full textThe current hike in price of conventional energy feedstuff warrants an intensified effort for a sustainable alternative that would not compromise performance and meat quality of poultry birds. The study evaluated the carcass trait and meat quality of finisher broiler chickens fed diets containing highly processed cassava peel meal at 50 % inclusion level in replacement of maize. Three hundred and twenty Cobb500 broiler chickens were allocated to 4 dietary treatments on a weight equalisation basis. Diet 1 = control diet (corn-soybean meal based diet) containing 4.0 g kg−1 digestible methionine (MET), 0.96 g kg−1 digestible lysine, diet 2 = diet containing 50 % replacement of maize in diet 1 with high quality cassava peel meal and containing 4.0 g kg−1 digestible MET, 0.96 g kg−1 digestible lysine, diets 3 and 4 are similar to diet 2 except with higher MET and lysine concentrations. Diet 3 contains 4.4 g kg−1 digestible MET, 1.02 g kg−1 digestible lysine, and diet 4 contains 4.8 g kg−1 digestible MET, 1.08 g kg−1 digestible lysine. The study lasted for 3 weeks (finisher phase). The highest slaughtered, carcass, and small intestinal weight were recorded in birds fed diet 2 while the birds fed diet 3 had the least abdominal fat value (p 0.05). The water holding capacity and cooking loss percentage was highest in the meat of the chickens fed diet 4. The meat colour (redness, yellowness, and lightness) of chickens fed diet 4 recorded the highest value. The very low density of lipoprotein and triglyceride concentrations were least in the meat of chickens fed diet 2 (p 0.05). It can be concluded that supplementation of methionine/lysine to high quality cassava peel meal improved the carcass trait and meat quality of the broiler chickens. © Author(s) 2024
Year-To Differentiation of Black Tea Through Spectroscopic and Chemometric Analysis
No full textBu çalışmada, hasat yılının siyah çayın çeşitli spektral profilleri üzerindeki etkisi incelenerek, iki hasat yılından siyah çay örneklerinin ayırt edilmesi amaçlanmıştır. Her metodolojinin avantajlarından yararlanılarak, orta kızılötesi, UV-görünür ve floresan spektroskopisinin yetenekleri, çok değişkenli istatistiksel yöntemlerle birlikte kapsamlı bir şekilde incelenmiştir. Değişen iklim koşulları ve mevsimsel döngüler nedeniyle, çay gibi gıda ürünlerinin bileşimi bir hasat yılından diğerine daha değişken hale gelmiş ve genel ürün kalitesini etkilemiştir. Bu nedenle, 2021 ve 2022'de hasat edilen 205 çay örneğini incelemek için orta kızılötesi, UV-görünür ve floresan spektroskopisi kullanılmıştır. Orta kızılötesi spektrumlar hem demlenmiş hem de toz örnek formları için toplanırken, yalnızca demlenmiş örnekler diğer spektroskopik yöntemler kullanılarak analiz edilmiştir. Örnekleri hasat yılına göre sınıflandırmak için PLS-DA, OPLS-DA ve SIMCA modelleri geliştirilmiştir. Orta kızılötesi verilere dayanan modeller toz örnekler için %93,33 ve aşılanmış örnekler için %90,33 doğru sınıflandırma oranlarına ulaşmıştır. Ek olarak, floresan ve UV-görünür spektral veriler sırasıyla %98,3 ve %100 başarı oranlarıyla oldukça doğru sonuçlar vermiştir. SIMCA diğer çok değişkenli yöntemlerle karşılaştırıldığında daha düşük performans gösterse de bulgular spektroskopik tekniklerin kemometrik yaklaşımlarla entegre edilmesinin siyah çayı farklı yıllarda etkili bir şekilde izleyebileceğini böylece, çay üretiminde kalite kontrol ve sınıflandırma süreçlerinin iyileştirilmesine katkıda bulunabilir.In this study, the impact of the harvest year on various spectral profiles of black tea samples was examined, aiming to differentiate black tea samples from two harvest years. Utilizing the advantages of each methodology, the capabilities of mid-infrared, UV-visible and fluorescence spectroscopy have been extensively studied in combination with multivariate statistical methods. Due to changing climate conditions and seasonal cycles, the composition of food products like tea has become more variable from one harvest year to the next, influencing the overall product quality. Therefore, mid-infrared, UV-visible, and fluorescence spectroscopy were used to examine 205 tea samples that were harvested in 2021 and 2022. Mid-infrared spectra were gathered for both infused and powdered sample forms, whereas only the infused samples were analyzed using the other spectroscopic methods. Partial least-squares discriminant analysis (PLS-DA), orthogonal partial least-squares discriminant analysis (OPLS-DA) and soft independent modeling of class analogy (SIMCA) models were developed to classify the samples by harvest year. Models based on mid-infrared data achieved correct classification rates of 93.33% for powdered samples and 90.33% for infused samples. Additionally, fluorescence and UV-visible spectral data yielded highly accurate results, with success rates of 98.3% and 100%, respectively. Although SIMCA showed lower performance compared to other multivariate methods, these findings suggest that integrating spectroscopic techniques with chemometric approaches can effectively monitor black tea across different years. This could contribute to improved quality control and classification processes in tea production
Elektrikli Araçlar için Kablosuz Batarya Şarj Sisteminin İncelenmesi
No full textElektrikli araçlar, sürücülere konforlu ve ekonomik bir sürüş sağlamanın yanı sıra sıfır emisyon özelliğiyle çevreyi kirletmezler. Halihazırda, elektrikli araçlar iletken şarj teknolojisi ile şarj olmaktadırlar. Nufüsun yoğun olduğu bölgelerde ise batarya değiştirme yöntemine başvurulmaktadır. Ancak bu yöntemlerin hiçbiri literatürde menzil kaygısı olarak adlandırılan sorunu çözmemektedir. Bu noktada, kablosuz güç transferi yöntemi menzil sorununa çözüm önermektedir. Elektrikli araçlar bu yöntemle park veya hareket halindeyken fiziksel temasa gerek kalmadan şarj edilebilmektedir. Bu sayede pillere ve şarj hızına olan bağımlılık da azalır. Kablosuz şarj teknolojisi gelişen bir teknolojidir. Yüksek verimlilik ve güvenlik bu yöntemin kabul edilmesi için vazgeçilmez faktörlerdir. Bu tezde kablosuz şarj verimliliğini artırmak için bir dizi deney yapılmıştır. Deneylerde verimlilik ve maliyet ilişkisi ortaya çıkarılmıştır. Hava aralığı, kablo tipi, soğutma, görev döngüsü, transfer ortamı ve bobin yapısı gibi birçok parametrenin verimliliğe etkisi kapsamlı bir şekilde analiz edilmiştir. Bunlara ek olarak kablosuz güç transferi medyumunda (ortamında) değişikliğe gidilmiştir. Elektrikli araçların kablosuz şarj uygulamalarında transfer ortamı havadır. Bu tezde, transfer ortamı farklı malzemeler ile doldurularak kablosuz güç transferi uygulaması mekanik bakış açısıyla değerlendirilmiş ve bir kavram kanıtlama çalışması yapılmıştır. Bir lityum-iyon batarya pakedi farklı C oranlarında kablosuz olarak şarj edilmiştir.Electric vehicles do not pollute the environment with zero emissions, as well as providing comfortable and economical driving to drivers. Currently, electric vehicles are charged with conductive charging technology. In densely populated areas, the battery replacement method is used. However, none of these methods can solve the problem called 'range anxiety' in the literature. At this point, the wireless power transfer method proposes a solution to this problem. Electric vehicles can be charged while parked or in motion without physical contact with this method. In this way, dependence on batteries and charging speed also decreases. Wireless charging technology is a developing technology. High efficiency and safety are indispensable factors for the adoption of this method. In this thesis, a series of experiments were performed to increase wireless charging efficiency. The efficiency and cost relationship was revealed in experiments. The effects of many parameters, such as air gap, cable type, cooling, duty cycle, transfer environment, and coil structure, on efficiency have been comprehensively investigated. In addition, the wireless power transfer medium (environment) was changed. The transfer medium is air in wireless charging applications of electric vehicles. In this thesis, the transfer medium was filled with different materials. The wireless power transfer application was evaluated from a mechanical perspective, and a proof of concept was performed. A lithium-ion battery pack was charged wirelessly in different C-rates
Process improvement in the steel mold machining for aluminum alloy wheel low pressure casting industry
No full textAlçak basınçlı döküm yöntemi ile jant üretim endüstrisinde, Dökümhane bölümleri için sürekli üretim hatları gereklidir. Gerekli üretimi elde etmek için, kalıplar dökümhanelerde hazır olmalıdır. Bu nedenle, alçak basınçlı döküm kalıplarının üretim süresi mümkün olduğunca kısa olmalıdır. Üretimi en üst düzeye çıkarmak için mevcut kapasiteyi kullanmak, daha fazla yatırım yapmaktan çok daha önemlidir. Bu, operasyonların kapsamlı bir şekilde gözden geçirilmesini, süreçler arasında görevlerin dengelenmesini ve en verimli üretimi elde etmek için operasyon sürelerinin azaltılmasını gerektirir. Zamanla daha büyük jant boyutlarına olan artan talep, alt maça için daha uzun üretim sürelerine neden olur. Daha fazla yatırım yapmaktan ziyade, mevcut kapasiteyi en üst düzeye çıkarmak çok önemlidir. Bu, operasyonların kapsamlı bir şekilde gözden geçirilmesini, süreçler arasındaki görevlerin dengelenmesini ve en verimli üretimi elde etmek için operasyon sürelerinin azaltılmasını gerektirir. Bu tezin amacı, üretimin ortasında yapılan ısıl işlem aşamasını kaldırarak toplam üretim süresini azaltmak ve süreci iyileştirmektir. Bu araştırmanın amacı, yalın üretim ve değer akış haritalama, talaşlı imalat makine parametresi optimizasyonu, takım seçimi, makine verimliliği ve üretim hattı dengelemesini kullanarak süreçleri inceleyip üretim sürecini etkileyen unsurların kapsamlı bir şekilde anlaşılmasını sağlamaktır. Değer akış haritalama kullanılarak yeni bir üretim yöntemi önerilmiş ve uygulanmıştır. Ayrıca, yeni üretim tekniğinin neden olduğu sorunların üstesinden gelmek için Taguchi yöntemi ile deney tasarımı kullanılarak işleme parametre optimizasyonu yapılmıştır. Önerilen üretim yönteminin uygulanmasıyla operasyon sayısının 12'den 8'e düşürülmesi, işçilik süresinin %2.35 azaltılması, teslim süresinin %42.65 azaltılması, kapasitenin %2.35 arttırılması, seçili makinelerde kapasite dengelenmesi, makine parametrelerinin optimizasyonu gibi birçok iyileştirme sağlanmıştır.In the wheel production with low pressure die casting industry, continuous production lines are necessary for foundry departments. To achieve the required production, molds must be readily available at the foundry. Thereby, manufacture time of the low-pressure casting molds must be as short as possible. Utilizing the current capacity to maximize manufacturing is crucial rather than investing even more. This requires a thorough review of operations, balancing tasks between processes, and reducing operation times to achieve the most efficient production. Reducing total production time and process improvement by removing heat treatment phase in the middle of the production is the main objective of this thesis. The goal of this research is to give a thorough understanding of the elements impacting the production process by exploring process improvements utilizing lean manufacturing and value stream mapping, machine parameter optimization, tool selection, machine efficiency, and production line balancing. With using Value Stream Mapping, a new production method is proposed and implemented. Also, machining parameter optimization has been done using Design of Experiment with Taguchi method to overcome the issues caused by the new manufacturing technique. Implementation of proposed method has offered various improvements such as reduction in number of operations 12 to 8, decrease in labor time with 2.35%, decrease in lead time by 42.65%, capacity increase with 2.35%, capacity line balancing in selected machines, machine parameter optimization and many more