The static and free vibration analyses of axially functionally graded elliptical beams via mixed FEM

The objective of this study is to investigate the behavior of the static and free vibration analyses of axially functionally graded elliptical planar curved beams using a mixed finite element method (MFEM) based on the Timoshenko beam theory. A two-noded curved mixed finite element has 12 field variables at each node. These variables denote three displacements, three cross-sectional rotations, three forces, two bending moments, and torque, respectively. The functionally graded material is composed of ceramic-particle material and metal-matrix material. The volume fraction of ceramic and metal materials varies along the beam axis. The effective material properties (modulus of elasticity, Poisson's ratio, and density) of the functionally graded material are determined according to the rule of mixture. It is aimed in the benchmark examples to present the influence of ceramic-particle material and non-homogeneity index of material gradation, the minimum radius of the elliptical beam, and boundary condition to the results of static and free vibration analysis in detail

Investıgatıon of Estımated Glycemıc Index and Some Functıonal Propertıes of Bread and Pasta Supplemented Wıth Enzyme Resıstant Starch Type 4

Interest in resistant starch (RS) as a food ingredient has been increasing because of its potential physiological benefits. In comparison with conventional fibers, such as bran, RS generally results in end products with better sensory and nutritional properties. In the present study, the effects of resistant starch type 4 (RS4) supplementation on nutritional and quality properties of bread and spaghetti were investigated. RS4 was added into bread and spaghetti formulations at different levels (15%, 20%, 25%). Wheat bran (WB) was also added at 15% level in bread and spaghetti formulation for comparison since it is level commonly used by industry. RS4 supplementation had significant effect on rheology,such as increasingfarinograph water absorption, decreasing development time and stability. Similar to RS4, WB caused an increase in water absorption value and caused a decrease in stability value. RS4 caused a decrease in Alveography P, L and W values. Similar trend was observed in WB supplemented samples, except for P value. Loaf volumes of the breads supplemented with RS4 were higher than the bread supplemented with WB. Crust L* and b* values of the breads increased significantly with increasing level of RS4 supplementation but WB supplementation caused decreases in L* and b* values of the breads. The firmness values of RS4 and WB supplemented samples significantly increased and during 3-day storage. WB supplementation caused the highest increase in bread firmness indicating a faster staling rate compared to RS4 supplementation. RS4 caused increases in TOM values of spaghettis. TOM value of the sample supplemented with WB was higher than the sample supplemented with RS4 at the same supplementation level. The cooking loss (CL) values increased significantly with RS4 and WB supplementation. The spaghetti supplemented with WB had the highest CL value among all samples. Supplementation of RS4 and WB caused significant decreases in the firmness values of the cooked spaghettis and flexure values of uncooked samples. The stickiness values of the spaghettis increased significantly with RS4 and WB supplementation. RS4 did not caused a significant change in the L* and b* values of the samples. On the contrary, WB supplementation caused significant decreases in L* and b* values. RS4 caused increases total dietary fiber content (TDF), bile acid (BA) binding capacity values and caused decreases in vitro glycemic index (GI) values of the bread and spaghetti samples. The decrease in GI value and increase in BA binding capacity and TDF content of the bread supplemented with RS4 were better than WB at the same supplementation level. A similar trend was also observed in TDF content of RS4 supplemented spaghetti and RS4 caused comparable GI and BA binding value at the same bran supplementation level. Moreover, RS4 supplemented samples had generally better mineral bioavailability values compared to control and WB supplemented samples. The results showed that RS4 provided improvement in nutritional properties of spaghetti and bread. It resulted in better appearance and texture than WB supplementation in spaghetti/bread. RS4 can be a better dietary fiber source for bread/spaghetti compared to WB supplemented ones.Bir gıda bileşeni olarak, sahip olduğu potansiyel fizyolojik faydalar nedeniyle enzime dirençli nişastaya (EDN) olan ilgi artmaktadır. Kepek gibi geleneksel liflerle karşılaştırıldığında, EDN genellikle daha iyi duyusal ve besinsel özelliklere sahip ürün elde edilmesini sağlamaktadır. Bu çalışmada, Tip 4 Enzime Dirençli Nişasta (EDN4) ilavesinin ekmek ve spagettinin beslenme ve kalite özellikleri üzerindeki etkileri araştırılmıştır. EDN4, ekmek ve spagetti formülasyonlarına farklı seviyelerde (%15, %20, %25) ilave edilmiştir. Ayrıca karşılaştırma yapabilmek için endüstride yaygın olarak kullanılan %15 ilave oranında buğday kepeği de ekmek ve spagetti formülasyonlarına ilave edilmiştir. EDN4 ilavesinin hamur reolojisi üzerinde, Farinograf su absorpsiyonunu arttırmak, hamur gelişim süresini ve stabilitesini azaltmak gibi önemli etkileri olmuştur. Kepek ilavesi de su absorpsiyonunda artışa ve stabilite değerinde azalmaya neden olmuştur. EDN4 ilavesi Alveograf P, L ve W değerlerini azaltmıştır. Kepek ilavesi de P değeri hariç diğer değerler üzerinde benzer etkiyi göstermiştir. EDN4 ilaveli ekmeklerin hacimlerinin, kepek ilaveli ekmeklerden daha yüksek olduğu belirlenmiştir. Ekmek kabuğundaki L* ve b* renk değerleri artan EDN4 ilave oranıyla önemli oranda artarken kepek ilavesi L* ve b* renk değerlerinde azalmaya neden olmuştur. Ekmeklerin sertlik değerlerinde, EDN4 ve kepek ilavesiyle önemli bir artış gözlenirken, üç günlük depolama süresince kepek ilaveli ekmeklerin en yüksek sertlik değerine sahip olduğu belirlenmiştir. Bu durum, kepek ilavesinin ekmeğin bayatlama hızını EDN4 ilavesine göre daha fazla arttırdığını göstermiştir. Spagetti örneklerinin TOM değerleri EDN4 ilavesiyle artmıştır. Kepek ilaveli örneğin TOM değeri, aynı seviyede EDN4 ilaveli örnekten daha yüksektir. Pişme kaybı değerlerinde EDN4 ve kepek ilavesiyle önemli bir artış gözlenmiştir. En yüksek pişme kaybı değerinin kepek ilaveli örnekte olduğu belirlenmiştir. EDN4 ve kepek ilavesi, pişmiş spagettinin sertlik değerlerinde ve pişmemiş örneklerin bükülme değerlerinde azalmaya neden olmuştur. Spagettinin yapışkanlık değerleri de EDN4 ve kepek ilavesiyle artmıştır. Spagettilerin L* ve b* değerlerinde EDN4 ilavesiyle önemli bir değişiklik olmamıştır. Ancak kepek ilavesi L* ve b* değerlerinde azalmaya neden olmuştur. EDN4 ilavesiyle ekmek ve spagettilerin toplam besinsel lif içerikleri, safra asidi bağlama kapasitesi değerleri artmış, in vitro glisemik indeks (GI) değerleri azalmıştır. %15 EDN4 ilaveli ekmeğin GI değerindeki azalmanın ve besinsel lif içeriği ile safra asidi bağlama kapasitesindeki artışların aynı orandaki kepek ilaveli ekmekten daha iyi olduğu belirlenmiştir. EDN4 ilaveli spagettinin besinsel lif içeriği için aynı durum söz konusu iken safra asidi bağlama ve GI değerlerinin aynı orandaki kepek ilavesi ile benzer olduğu görülmüştür. Ayrıca, EDN4 ilaveli örnekler, kontrol ve kepek ilaveli örneklere göre daha iyi mineral biyoyararlanım değerlerine sahiptir. Sonuçlar EDN4’ün spagetti ve ekmeğin besinsel özelliklerini geliştirdiğini göstermektedir. EDN4 ilaveli spagetti/ekmek örneklerinin kepek ilaveli örneklerden daha iyi görünüş ve tekstüre sahip olduğu belirlenmiştir. Tüm bu sonuçlar değerlendirildiğinde EDN4’ün, ekmek/spagetti örnekleri için kepeğe kıyasla daha iyi besinsel lif kaynağı olabileceği düşünülebilir

In vitro glycemic index, bile acid binding capacity and mineral bioavailability of spaghetti supplemented with resistant starch type 4 and wheat bran

Arıbaş, Merve ( Aksaray, Yazar )In this study effects of resistant starch type 4 (RS4) on nutritional and quality properties of spaghetti were investigated. RS4 was added into spaghetti at different levels (15, 20 and 25%). Wheat bran was also added to spaghetti at 15% level. RS4 supplementation caused lower negative effects on quality properties (total organic matter value, color and textural properties) than bran supplementation. The results point out that RS4 supplementation of spaghetti caused higher total dietary fiber content and comparable glycemic index value at the same bran supplementation level. RS4 caused an increase in bile acid binding capacity and expected to have positive effects on cholesterol metabolism. Moreover, RS4 supplemented spaghetti had generally better mineral bioavailability values compared to bran supplemented and control spaghettis. Overall results indicated that RS4 supplementation provided improvement in nutritional properties of spaghetti and can be an alternative ingredient for fiber supplemented spaghetti compared to bran

Effects of resistant starch type 4 supplementation of bread on in vitro glycemic index value, bile acid‐binding capacity, and mineral bioavailability

Arıbaş, Merve ( Aksaray, Yazar )Background and objectives: RS4 is an alternative dietary fiber source with some potential physiological benefits giving better quality end products. Common dietary fiber sources including bran usually have deteriorative effect on color, textural properties, and consumer acceptability of breads. This study was designed to investigate the effect of RS4 supplementation on the bread quality as well as mineral bioavailability, bile acid-binding capacity, in vitro glycemic index. Findings: Loaf volumes of the breads supplemented with RS4 were higher than the bread supplemented with wheat bran (WB). Among the bread samples, the one supplemented with WB had the darkest color and highest firmness values. During storage, WB supplementation caused the highest increase in bread firmness. RS4 supplementation caused higher total dietary fiber (TDF) and mineral bioavailability values and lower in vitro glycemic index than bran supplementation. Conclusions: RS4 supplementation of bread caused increases in TDF content, bile acid-binding capacity, and mineral bioavailability and has less deteriorative effect on the quality than WB supplementation. Breads supplemented with WB had a faster staling rate than the breads supplemented with RS4. Significance and novelty: Besides the better appearance and texture of the RS4 supplemented bread samples, the improvement in nutritional properties proved that RS4 is a better dietary fiber source than WB...

The static and stress analyses of axially functionally graded exact super-elliptical beams via mixed FEM

In this paper, the static response and normal/shear stresses of axially functionally graded exact super-elliptical beams are presented via a warping-included mixed finite element method. Super-elliptical axis geometry is derived over the exact functions of planar curves. The constitutive equations are obtained from three-dimensional elasticity theory. The mixed finite element formulation is enhanced by including the warping deformations via displacement-type finite elements on the cross-section. The two-noded curved mixed finite element has twenty-four degrees of freedom in total. Satisfactory results are obtained for the warping-included normal/shear stresses, displacements and reactional forces of axially functionally graded exact super-elliptical beams even with lesser degrees of freedom compared to the three-dimensional behavior of brick finite elements. As benchmark examples, the influences of high axial curvature, cross-sectional geometry and material gradation on the static response and stresses of axially functionally graded exact super-elliptical beams are investigated.WOS:0006967885000012-s2.0-8511519917

Forced vibration analysis of composite-geometrically exact elliptical cone helices via mixed FEM

In this pioneering study, the cross-sectional warping included transient response and normal/shear stress components of composite elliptical and elliptical cone helices over exact axis geometry are investigated using a mixed FEM. The transient analysis is performed using the Newmark time integration algorithm with or without the amplitude decay factor. The constitutive equations of composite curved rods are derived from three-dimensional elasticity theory. A displacement-type finite element formulation computing the warping-included torsional rigidity is incorporated with the mixed finite element formulation. The curvatures and displacement-type finite elements are used to estimate the normal and shear stress distributions on the respective cross-sections. The maximum normal/shear stresses of a composite straight beam are compared with the literature. An excellent agreement is obtained for the results of an exact elliptical cone helix under dynamic loads compared to the results of 3D solid finite elements. During the implementation of the time integration scheme, the first and second time derivatives of forces and moments are preserved, and their time histories are discussed. Finally, the influences of helix geometry, lamination, and the ratios of material constants on the transient response besides the stresses are investigated. All the numerical examples in this paper are original for the literature.Istanbul Technical Universit

Forced vibration analysis of composite-geometrically exact elliptical cone helices via mixed FEM

In this pioneering study, the cross-sectional warping included transient response and normal/shear stress components of composite elliptical and elliptical cone helices over exact axis geometry are investigated using a mixed FEM. The transient analysis is performed using the Newmark time integration algorithm with or without the amplitude decay factor. The constitutive equations of composite curved rods are derived from three-dimensional elasticity theory. A displacement-type finite element formulation computing the warping-included torsional rigidity is incorporated with the mixed finite element formulation. The curvatures and displacement-type finite elements are used to estimate the normal and shear stress distributions on the respective cross-sections. The maximum normal/shear stresses of a composite straight beam are compared with the literature. An excellent agreement is obtained for the results of an exact elliptical cone helix under dynamic loads compared to the results of 3D solid finite elements. During the implementation of the time integration scheme, the first and second time derivatives of forces and moments are preserved, and their time histories are discussed. Finally, the influences of helix geometry, lamination, and the ratios of material constants on the transient response besides the stresses are investigated. All the numerical examples in this paper are original for the literature.Research Foundation of ITUIstanbul Technical University [MGA-2017-4739]This research is supported by the Research Foundation of ITU (Project no: MGA-2017-4739). This support is gratefully acknowledged by the authors.WOS:0005722008000012-s2.0-8509137390