Relationship between Barcol hardness and flexural modulus degradation of composite sheets subjected to flexural fatigue

Raif Sakin 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.19 No.6

The aim of this study is to investigate the relationship between Barcol hardness (H) and flexural modulus (E) degradation of composite sheets subjected to flexural fatigue. The resin transfer molding (RTM) method was used to produce 3-mm-thick composite sheets with fiber volume fraction of 44%. The composite sheets were subjected to flexural fatigue tests and Barcol scale hardness measurements. After these tests, the stiffness and hardness degradations were investigated in the composite sheets that failed after around one million cycles (stage III). Flexural modulus degradation values were in the range of 0.41-0.42 with the corresponding measured hardness degradation values in the range of 0.25-0.32 for the all fatigued composite sheets. Thus, a 25% reduction in the initial hardness and a 41% reduction in the initial flexural modulus can be taken as the failure criteria. The results showed that a reasonably well-defined relationship between Barcol hardness and flexural modulus degradation in the distance range.

Layup Design Optimization for E-glass Woven Roving Fabric Reinforced Polyester Composite Laminates Produced by VARTM

Raif Sakin 한국섬유공학회 2021 Fibers and polymers Vol.22 No.2

In this study, a satisfactory number of actual test results were used to optimize the stacking sequence design ofbidirectional glass-woven fabrics in polyester composite laminates. In optimization, parameters such as glass-woven fabricswith five different areal weights, stacking sequence, number of plies (PLY), and off-axis fiber directions (DEG) were taken asinput factors. Values such as tensile strength (UTS) and flexural strength (UFS), mechanical anisotropy factors (AFs), andresin permeability coefficient of stacked glass-fabrics were taken as output responses. In this study, a laboratory-scalevacuum assisted resin transfer molding (VARTM) process was established. Composite laminates with sixteen differentstacking and six different number of plies are produced. Mechanical properties such as tensile and three-point flexure havebeen tested for the composite laminates obtained. In addition, the resin permeability coefficient for each laminate and the AFfor tensile and flexural module depending on fiber direction were calculated during production. Many actual test data wereobtained versus response to seven factors and five variables. Instead of the experimental designs recommended in responsesurface methodology (RSM), 64 actual test data were used as responses of the model. In the optimization with the Minitab,the minimum mechanical AF was desired in return to maximum UTS, UFS, and permeability coefficient. Optimum stackingsequence, PLY, DEG, permeability coefficient, and AFs were determined through using RSM. Consequently, the mostoptimal composite laminate was suggested in real terms in the desirability rate of laminate D=0.6731 with the stackingsequence of [822252]6, six plies, and 0 °/90 ° fiber direction.

The Nutritive Value of Live Yeast Culture (Saccharomyces cerevisiae) and Its Effect on Milk Yield, Milk Composition and Some Blood Parameters of Dairy Cows

Yalcin, Sakine,Yalcin, Suzan,Can, Plnar,Gurdal, Arif O.,Bagci, Cemalettin,Eltan, Onder Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.10

This study was conducted to determine the nutritive value of live yeast culture (RumiSacc, Saccharomyces cerevisiae) and to investigate its effects on milk yield, milk composition and some blood parameters in lactating cows. Six multiparous Holstein cows were allocated to two groups of three cows and assigned randomly to one of two diets in a cross-over experiment. Daily 50 g RumiSacc was top dressed at the p.m. feeding for the treatment group. RumiSacc supplied a high protein and energy with high organic matter digestibility values (83.35%) determined by in vitro enzymatic analysis. Yeast culture supplementation significantly increased milk yield, tended to increase fat yield, protein yield and lactose yield of milk. Methylated fatty acid level of 18:3 (n-3) in milk fat was increased by yeast culture supplementation. The concentrations of methionine, phenyalanine, tyrosine, tryptophan and taurine were significantly increased with dietary inclusion of yeast culture. Live yeast culture supplementation did not affect other performance characteristics, milk quality characteristics and blood parameters. As a conclusion live yeast culture (RumiSacc, Saccharomyces cerevisiae) had high nutritive value and positive effects on milk production and some milk quality characteristics in lactating cows under field conditions.

The Effects of Dietary Garlic Powder on the Performance, Egg Traits and Blood Serum Cholesterol of Laying Quails

Yalcin, Sakine,Onbasilar, Ilyas,Sehu, Adnan,Yalcin, Suzan Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.6

This study was conducted to study the effects of dietary garlic powder on laying performance, egg traits and blood serum cholesterol level of quails. A total of three hundred quails (Coturnix coturnix japonica) aged nine weeks were used. They were allocated to 3 dietary treatments. Each treatment comprised 5 replicates of 20 quails. The diets were supplemented with 0, 5 and 10 g/kg garlic powder. The experimental period lasted 21 weeks. The addition of garlic powder did not significantly affect body weight, egg production, feed consumption, feed efficiency, egg shell thickness, egg albumen index, egg yolk index and egg Haugh unit. Adding 5 and 10 g/kg garlic powder to the laying quail diets increased egg weight (p<0.01). Egg yolk cholesterol and blood serum cholesterol concentration were reduced with garlic powder supplementation. The results of this study demonstrated that garlic powder addition had a significant cholesterol-reducing effect in serum and egg yolk without adverse effects on performance and egg traits of laying quails.

The Effects of Dietary Supplementation of L-carnitine and Humic Substances on Performance, Egg Traits and Blood Parameters in Laying Hens

Yalcin, Sakine,Ergun, Ahmet,Ozsoy, Bulent,Yalcin, Suzan,Erol, Handan,Onbasilar, Ilyas Asian Australasian Association of Animal Productio 2006 Animal Bioscience Vol.19 No.10

This experiment was carried out to determine the effects of supplementation of L-carnitine and humic substances alone or in combination in laying hen diets on performance, egg traits and blood parameters. A total of 180 IGH type brown laying hens aged 22 weeks were employed in a completely randomized block design with one control group and three treatment groups. Each group was divided into five replicates as subgroups, each comprising 9 hens. The diets of the first, second and third treatment groups were supplemented with 0.1 g/kg L-carnitine, 1.5 g/kg humic substances (Farmagulator$^{(R)}$ Dry Plus) and 0.1 g/kg L-carnitine+1.5 g/kg humic substances, respectively. The experimental period lasted 18 weeks. Feeding supplemental carnitine, humic substances or carnitine+humic substances resulted in increases in body weight gain (p<0.05). Dietary treatments did not significantly affect daily feed intake, daily metabolizable energy intake, egg production, egg weight, feed efficiency, mortality, egg shape index, egg breaking strength, egg shell thickness, egg albumen index, egg yolk index, egg Haugh unit and the percentages of egg shell, albumen and yolk. Supplementation of humic substances reduced egg yolk cholesterol as mg per g yolk and mg per yolk (p<0.05). Blood serum parameters were not affected by the supplementation of carnitine, humic substances or carnitine+humic substances. The results in this study demonstrated that humic substances supplementation reduced egg cholesterol without adverse effects on performance, egg traits and blood parameters of laying hens. It was concluded that the usage of L-carnitine alone or in combination with humic substances in diets had no beneficial effects in laying hens.

Alkaloids from Amaryllidaceae III. Alkaloids from the Bulbs of Pancratium maritimum

Bilge Sener,Sakine Konukol,Cornelis Kruk,Upendra K. Pandit 한국생약학회 1998 Natural Product Sciences Vol.4 No.3

The extract from the bulbs of Pancratium maritimum L. afforded 12 alkaloids belonging to the skeletally six different groups of the Amaryllidaceae allcaloids. In this paper, the isolation and identification of (-)-N-dernethyl-galanthamine (1), (+)-tazettine (2) and (-)-2-O-demethylmontanine (3) are described. Their structures have been determined by using extensive spectroscopic techniques. This is the first report describing the occurrence of 1 and 3 in this plant.

Low-shrinking composites. Are they reliable for bonding orthodontic retainers?

Uysal, Tancan,Sakin, Caglar,AI-Qunaian, Talal The Korean Association Of Orthodontists 2011 대한치과교정학회지 Vol.41 No.1

Objective: To evaluate the shear bond strength (SBS), fracture mode, wire pull out (WPO) resistance and microleakage between low-shrinking and conventional composites used as a lingual retainer adhesive. Methods: A total of 120 human mandibular incisor teeth, extracted for periodontal reasons, were collected. Sixty of them were separated into two groups. To determine the SBS, either Transbond-LR (3M-Unitek) or Silorane (3M-Espe) was applied to the lingual surface of the teeth by packing the material into standard cylindrical plastic matrices (Ultradent) to simulate the lingual retainer bonding area. To test WPO resistance, 20 samples were prepared for each composite where the wire was embedded in the composite materialand cured. Then tensile stress was applied until failure of the composite occurred. The remaining 60 teeth were divided into two groups and multi-stranded 0.0215-inch diameter wire was bonded with the same composites. Microleakage was evaluated by the dye penetration method. Statistical analyses were performed by Wilcoxon, Pearson chi-square, and Mann-Whitney-U tests at p < 0.05 level. Results: The SBS and WPO results were not statistically significant between the two groups. Significant differences were found between the groups in terms of fracture mode (p < 0.001). Greater percentages of the fractures showed mix type failure (85%) for Silorane and adhesive (60%) for Transbond-LR. Microleakage values were lower in low-shrinking composite than the control and this difference was found to be statistically significant (p < 0.001). Conclusions: Low-shrinking composite produced sufficient SBS, WPO and microleakage values on the etched enamel surfaces, when used as a lingual retainer composite.

Simple Preparation of Cuprous Oxide Nanoparticles for Catalysis of Azide-alkyne Cycloaddition

Amini, Mojtaba,Ramezani, Sakine,Anbari, Alireza Pourvahabi,Beheshti, Abolghasem,Gautam, Sanjeev,Chae, Keun Hwa SAGE Publications 2018 Journal of chemical research Vol.42 No.3

Low-shrinking composites. Are they reliable for bonding orthodontic retainers?

Tancan Uysal,Caglar Sakin,Talal Al-Qunaian 대한치과교정학회 2011 대한치과교정학회지 Vol.41 No.1

Objective: To evaluate the shear bond strength (SBS), fracture mode, wire pull out (WPO) resistance and microleakage between low-shrinking and conventional composites used as a lingual retainer adhesive. Methods: A total of 120 human mandibular incisor teeth, extracted for periodontal reasons, were collected. Sixty of them were separated into two groups. To determine the SBS, either Transbond-LR (3M-Unitek) or Silorane (3M-Espe) was applied to the lingual surface of the teeth by packing the material into standard cylindrical plastic matrices (Ultradent) to simulate the lingual retainer bonding area. To test WPO resistance, 20 samples were prepared for each composite where the wire was embedded in the composite materialand cured. Then tensile stress was applied until failure of the composite occurred. The remaining 60 teeth were divided into two groups and multi-stranded 0.0215-inch diameter wire was bonded with the same composites. Microleakage was evaluated by the dye penetration method. Statistical analyses were performed by Wilcoxon, Pearson chi-square, and Mann-Whitney-U tests at p < 0.05 level. Results: The SBS and WPO results were not statistically significant between the two groups. Significant differences were found between the groups in terms of fracture mode (p < 0.001). Greater percentages of the fractures showed mix type failure (85%) for Silorane and adhesive (60%) for Transbond-LR. Microleakage values were lower in low-shrinking composite than the control and this difference was found to be statistically significant (p < 0.001). Conclusions: Low-shrinking composite produced sufficient SBS, WPO and microleakage values on the etched enamel surfaces, when used as a lingual retainer composite. (Korean J Orthod 2011;41(1):51-58)

Experimental and numerical investigation of RC column strengthening with CFRP strips subjected to low-velocity impact load

Omer Mercimek,Ozgur Anil,Rahim Ghoroubi,Shaimaa Sakin,Tolga Yilmaz 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.79 No.6

Reinforced concrete (RC) square columns are vulnerable to sudden dynamic impact loadings such as the vehicle crash to the bridges of highway or seaway, rock fall, the collision of masses with the effect of flood and landslide. In this experimental study RC square columns strengthened with and without CFRP strip subjected to sudden low velocity lateral impact loading were investigated. Drop-hammer testing machine was used to apply the impact loading to RC square columns. The test specimens were manufactured with square cross sections with 1/3 geometric scale. In scope of the study, 6 test specimens were manufactured and tested. The main variables considered in the study were the application point of impact loading, and CFRP strip spacing. A 9.0 kg mass was allowed to fall freely from a height of 1.0 m to apply the impact loading on the columns. During the impact tests, accelerations, impact force, column mid-point displacements and CFRP strip strains measurements were taken. The general behavior of test specimens, collapse mechanisms, acceleration, displacement, impact load and strain time relationships were interpreted, and the load displacement relationships were obtained. The data from the experimental study was used to investigate the effect of variables on the impact performances of RC columns. It has been observed that the strengthening method applied to reinforced concrete columns, which are designed with insufficient shear strength, insufficient shear reinforcement and produced with low strength concrete, using CFRP strips significantly improves the behavior of the columns under the effect of sudden dynamic impact loading and increases their performance. As a result of the increase in the hardness and rigidity of the specimens strengthened by wrapping with CFRP strips, the accelerations due to the impact loading increased, the displacements decreased and the number of shear cracks formed decreased and the damage was limited. Moreover, the finite element analyses of tested specimens were performed using ABAQUS software to further investigate the impact behavior.