Fatigue behavior of hybrid continuous-discontinuous fiber-reinforced sheet molding compound composites under application-related loading conditions

Hybrid continuous-discontinuous sheet molding compound (SMC) composites are considered suitable candidates for structural automotive applications, due to their high mass-specific mechanical properties combined with high geometrical flexibility and low costs. Since structural automotive parts are subject to repeated loading, profound knowledge of their fatigue behavior is required. This paper presents an experimental study on the bending fatigue behavior of hybrid SMC with discontinuous glass fibers in the core and unidirectional continuous carbon fibers in the face layers. Effects of hybridization on the S-N behavior and stiffness degradation have been analyzed in constant amplitude fatigue tests under 3-point bending load at different temperatures and frequencies. Microscopic investigations on polished specimen edges were used to study the damage behavior. The ultimate flexural strength at quasi-static (UFSS) and fatigue strain rate (UFSF) of the hybrid composite was 54 % and 59 % higher than that of discontinuous SMC, respectively. In contrast, the flexural fatigue strength at 2.6⋅106 cycles increased by 258 %. The relative stiffness degradation of the hybrid composites was smaller during most of their fatigue lives due to the continuous carbon fiber reinforcement. The carbon fiber ply on the compression loaded side was the first ply to fail. Fatigue stress significantly decreased at 80 °C due to early kinking of the continuous carbon fiber-reinforced ply on the compression loaded side. Variation of frequency had no significant effect on the fatigue behavior of both discontinuous and continuous-discontinuous SMC

Fatigue behavior of hybrid continuous-discontinuous fiber-reinforced sheet molding compound composites under application-related loading conditions

Hybrid continuous-discontinuous sheet molding compound (SMC) composites are considered suitable candidates for structural automotive applications, due to their high mass-specific mechanical properties combined with high geometrical flexibility and low costs. Since structural automotive parts are subject to repeated loading, profound knowledge of their fatigue behavior is required. This paper presents an experimental study on the bending fatigue behavior of hybrid SMC with discontinuous glass fibers in the core and unidirectional continuous carbon fibers in the face layers. Effects of hybridization on the S-N behavior and stiffness degradation have been analyzed in constant amplitude fatigue tests under 3-point bending load at different temperatures and frequencies. Microscopic investigations on polished specimen edges were used to study the damage behavior. The ultimate flexural strength at quasi-static (UFS$^S$) and fatigue strain rate (UFS$^F$) of the hybrid composite was 54 % and 59 % higher than that of discontinuous SMC, respectively. In contrast, the flexural fatigue strength at 2.6⋅10S$^6$ cycles increased by 258 %. The relative stiffness degradation of the hybrid composites was smaller during most of their fatigue lives due to the continuous carbon fiber reinforcement. The carbon fiber ply on the compression loaded side was the first ply to fail. Fatigue stress significantly decreased at 80 °C due to early kinking of the continuous carbon fiber-reinforced ply on the compression loaded side. Variation of frequency had no significant effect on the fatigue behavior of both discontinuous and continuous-discontinuous SMC

Anesthetic Efficacy of Cymbopogon citratus Essential Oil as a Herbal Agent in Two Ornamental Fish Species

The efficacy of Cymbopogon citratus essential oil (CcEO) as a herbal anesthetic agent was evaluated for two ornamental fish species, Sciaenochromis fryeri and Labidochromis caeruleus. Fish were exposed to various essential oil concentrations and the lowest effective concentrations were determined according to deep anesthesia (AD<3 min) and full recovery (RF<10 min) times. CcEO showed anesthetic traits and induced AD in S. fryeri and L. caeruleus. The lowest effective concentrations was 200 μl/L for S. fryeri (AD; RF → 122 ± 1.8 s; 638 ± 8.9 s) and 200 μl/L for L. caeruleus (AD ; RF → 139 ± 6.9 s ; 625 ± 11.1 s). At concentration of 25 μl/L C. citratus essential oil did not induce AD in both of ornamental fish species. No significant differences were found between fish species in terms of induction and recovery times for same concentrations excluding AD time of 200 μl/L concentration. Although the fastest AD were obtained by 300 μl/L, recovery times were prolonged and fish did not full recover in 20 min. Induction and recovery times for CcEO were significantly dependent on concentrations and negative relationships were recorded between AD and RF. Neither mortality nor adverse effects were observed on two fish species. As a result, CcEO showed anesthetic properties for S. fryeri and L. caeruleus

The Efficacy of Chamomile (Matricaria chamomilla l.) Oil as a Promising Anaesthetic Agent for Two Freshwater Aquarium Fish Species

The efficacy of anesthetic chamomile oil (from Matricaria chamomilla L.) was evaluated in two freshwater aquarium fish species, Electric Blue Hap (Sciaenochromis fryeri) and Yellow Princess (Labidochromis caeruleus). Fish were exposed to ten concentrations of anesthetic (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 and 1.0 ml/L). The optimal doses identified as 0.6 ml/L for deep anesthesia (A5) for both two species. The minimal sedative dose at the stage of loss of equilibrium (A3) was found to be 0.3 ml/L. The induction time generally decreased significantly with increasing concentrations of chamomile oil for all treatment groups. Recovery time tended to increase with increased chamomile oil at concentrations lower than 0.7 ml/L, but after this concentration it decreased. Chamomile oil proved to be effective as an anesthetic for both ornamental fish species. These findings suggest that chamomile oil is a promising anesthetic agent for aquaculture. However, further studies should be focused on species based investigations on the effect of temperature, transfer of fish, and their effect on antioxidant and oxidant status, in order to gather further information

Spawning and larval rearing in hybrid striped bass (Morone chrysops + x Morone saxatilis >) in Turkey [Türkiye’de hibrit çizgili levrek baliklarinda (Morone chrysops + X Morone saxatilis >) yumurtlatma ve larva yetiştiriciliği]

This study is the first spawning and larval rearing of the F1 hybrid striped bass (Morone chrysops + X M. saxatilis >) grown in culture conditions in Turkey. The F1 Hybrid striped bass was fed with commercial pellet feed in floating net cages. They reached the sexual maturity at two years old. Female brood fish were given 30 µg/kg of LHRH-a (Lutenizing hormone releasing hormone analogue) and male fish given 10 µg/kg; of CHP(Dried carp pituitary), 4 mg/kg was used for the female and half that amount for the male for induced breeding. The fish injected LHRHa were successfully induced to both strip spawning and tank spawning by a single hormone injection. However, fish injected CPH and saline, untreated control did not spawn. Latency period was found to be 20.41±0.91 hour. In term of fertilization rate, larval deformity rate no significant difference was found between tank spawning and strip spawning (p&gt;0.05).Fertilization rates ranged from 56.3% to 85.4% and hatch rates were between 0.99% and 46.88%, whereas the level of larval deformities ranged between 81.25% and 100%. Hatched larvae were placed into 400-liter rectangular tanks with water discharge of 4 liter/minute at a stocking density of 30 larvae/liter. After larvae hatching, they were given artemia nauplii for 5-19 days. Trout granule feed (300-500 micron) also started to be given in addition to artemia nauplii afterwards. Granule feed was started eating completely 24 th days. The larvae obtained from a single hatch in the production season reached 2.87 cm length in 32 days with 2.7% survival rate. Of this study was terminated due to white spot disease (Ichtyophthirius multifilis) arising from sudden change in water temperature. The F2 progenies were not deemed to be available for aquaculture due to poor fertilization, poor hatching, low survival rate and high deformity rate. For the progenies of the hybrid striped bass that grow in natural water, it was suggested that their ecology in waters in Turkey be first studied and brought into aquaculture afterwards. © 2015 Cevkor Vakfi. All rights reserved

Production and performance of triploid rainbow trout in Turkey

WOS: 00023365820001

Comparison of growth performance, gonadal structure and erythrocyte size in triploid and diploid brown trout (salmo trutta fario L, 1758) [Triploit ve diploit dere alabai{dotless}klari{dotless}nda (Salmo trutta fario L, 1758) büyüme performansi{dotless}, gonat yapi{dotless}si{dotless} ve eritrosit boyutunun karşi{dotless}laşti{dotless}ri{dotless}lmasi{dotless}]

The aim of this study was to compare growth, gonadal structure and red blood cell sizes of triploid and diploid brown trout (Salmo trutta fario). Triploidy was induced by providing a heat shock treatment to the fertilized eggs. From the 18th month post-fertilization triploid (TBT) and control diploid (CBT) brown trout groups were investigated up to 32nd month. Survival, specific growth rate, feed conversion ratio, condition factor, relative growth rate, absolute growth rate, gonadosomatic index, hepatosomatic index and carcass yield were determined in both groups. It has been determined that the triploid fish showed greater live weight than diploid fish despite the difference was not significant (P&gt;0.05). In triploid group triploidisation success was obtained as 95% and male/female ratio was found as 44.4-55.6%. The red blood cells were significantly larger in triploids than diploid ones (P&lt;0.05). Regarding histological section of gonads, triploidy resulted in reduced gonadal development in female, while triploid males seem to exhibit normal gonadal development. Our results suggest that since triploid females could grow more than males, the growth performance studies on triploid brown trout should be performed with all-female stocks under fish farming practices especially for the production of large size trout. © Published by Central Fisheries Research Institute (CFRI) Trabzon, Turkey

The effects of clove oil on adult males and females of rainbow trouts (Oncorhynchus mykiss) and brown trouts (Salmo trutta fario)

Anesthetics are used for performing basic procedures such as weighing, tagging, experimental work, harvesting, spawning procedures and during transportation to prevent physical injury and reduce metabolism in aquaculture. Using of natural plant materials such as clove oil (eugenol) for sedation of fish becomes more important in aquaculture industry. In this experiment, different concentrations of clove oil (20, 30 and 40 ppm) were applied on broodstock of brown trout (Salmo trutta fario) and rainbow trout (Oncorhynchus mykiss) of different genders. Times to induction and recovery from anesthesia were measured. No fish died during trials. Induction times of anesthesia varied with clove oil concentrations, decreasing with the increase of clove oil concentrations. On the other hand, recovery times increased with decreasing of clove oil concentrations only on male trouts. The induction times for fish exposed to 20 ppm clove oil were generally longer compared to 30 and 40 ppm (p<0.05). Dose of 30 ppm clove oil produced rapid anesthesia with shorter recovery for females in both of species. On the other hand, the shorter recovery times were recorded for males in both species at 20 ppm. According to our results, recovery times were more gender-dependent for adult rainbow and brown trouts (p<0.05). Recovery times were shorter in adult females than males, especially for 30 and 40 ppm clove oil, while male brown trouts were induced longest times in these dosages (p<0.05). It can be said that as an environmental friendly substance clove oil with optimal dose of 30 ppm can be administered for anesthesia safely in both of adult male and female trouts