Experimental study of aerodynamic behaviour of stretchable sport fabrics

In recent years, there has been great interest in the effects of different garments and their aerodynamic characteristics. It is widely believed that the reduction of aerodynamic drag can enhance athlete’s performance. There has been little understanding in the aerodynamic properties and behaviours of athlete’s garment as limited research is reported in the open literature. Therefore, the primary objective of this research is to understand the aerodynamic characteristics and gain a greater insight in order to establish relations between sports garments’ physical parameters and aerodynamic properties. A series of stretchable knitted and woven fabrics used in speed sports garments (e.g., sprint, cycling, speed skating, downhill skiing, ski jumping and swimming) have been studied for a wide range of Reynolds numbers (Re) and angles of attack (α). The findings revealed that the drag polar (C L /C D ratio) for 3D circular cylinder with smooth and rough surfaces (varied by knitted and woven fabrics) has been established for a range of Reynolds numbers (Re = 5.06 × 10 4 to 2.30 × 10 5 ) and angles of attack (α = 0° to 90°). The drag polar allows determining the aerodynamic efficiency of sports fabrics (i.e., garments) and their optimal design. The aerodynamic behaviour of knitted fabrics is found to be quite different to that of woven fabrics. With an increase of stretch, the surface morphology of knitted fabrics becomes courser and thereby triggers an early airflow transition. In contrast, the stretch on woven fabrics makes the surface morphology smoother which delays the flow transition. The minimum drag coefficient (C Dmin ) of stretchable knitted fabrics is directly proportional to relative roughness whereas the critical Reynolds numbers is inversely proportional to the relative roughness (ε = 1.39 × 10 -4 to 7.73 × 10 -4 ) within Reynolds numbers investigated (Re crit = 1.83 × 10 5 to 1.00 × 10 5 ). On the other hand, the minimum drag coefficient (C Dmin ) of stretchable woven fabrics is proportional to the relative roughness, however the relationship of critical Reynolds numbers (Re crit = 1.17 × 10 5 to 2.34 × 10 5 ) with the relative roughness (ε = 3.689 × 10 -4 to 1.319 × 10 -4 ) is non-linear. Knitted fabrics with lower relative roughness, distance and gap area between yarns generate greater aerodynamic efficiency (C L /C D ) at high Reynolds numbers. Similarly with the higher relative roughness, distance and gap area between yarns, the knitted fabrics offers an aerodynamic benefit at low Reynolds numbers. A notable reduction of aerodynamic benefit in woven fabrics was found under unstretched condition. However with increased stretches, the aerodynamic advantage (C L /C D ) increases almost linearly. The stretched woven fabrics are found to be aerodynamically beneficial at high Reynolds numbers whereas the stretched knitted fabrics are at low Reynolds numbers. The practical implication of these research findings is multi-fold. The drag polar of smooth and rough cylindrical surfaces can be applied not only for the development of engineered sports garments but also for the optimal athlete’s body orientation. Additionally, the findings can be utilised in developments of various projectile shapes for military and sports applications

Aerodynamic analysis of Speedo Fastskin-I Swimsuit

Swimming is one of the most energy intensive sporting events, where a winner is decided by a short margin. The winning time margin can be increased by various means, including engineered outfits within the game's regulations. In swimming, apart from optimisation of the swimmer's body, an appropriately devised swimsuit can play a significant role in reducing the drag, thereby enhancing the winning time margin. The main motivation for undertaking this study stems from the increasing levels of technical sophistication in the swimsuits that are claimed by the manufacturers for performance enhancement. Therefore, the goal of this paper is to undertake an experimental study with microscopic illustration of the swimsuit fabric, and its effects on aerodynamic properties. The study utilised a commercial swimsuit under stretched and un-stretched conditions of fabric morphology, and their impact on aerodynamic drag. This study was conducted using a wind tunnel for a range of Reynolds numbers. The simplified body shape was used to determine the aerodynamic drag. The finding of this study illustrates that there is a significant difference between the aerodynamic drag for the stretched and un-stretched surface morphology of the Speedo FS-I swimsuit. Furthermore, the microscopic analysis of the stretched and un-stretched fabric was undertaken to extend our undertstanding

Mindfulness meditation targets transdiagnostic symptoms implicated in stress-related disorders: Understanding relationships between changes in mindfulness, sleep quality, and physical symptoms

Mindfulness-Based Stress Reduction (MBSR) is an 8-week meditation program known to improve anxiety, depression, and psychological well-being. Other health-related effects, such as sleep quality, are less well established, as are the psychological processes associated with therapeutic change. This prospective, observational study (n=213) aimed to determine whether perseverative cognition, indicated by rumination and intrusive thoughts, and emotion regulation, measured by avoidance, thought suppression, emotion suppression, and cognitive reappraisal, partly accounted for the hypothesized relationship between changes in mindfulness and two health-related outcomes: sleep quality and stress-related physical symptoms. As expected, increased mindfulness following the MBSR program was directly correlated with decreased sleep disturbance (r=-0.21, p=0.004) and decreased stress-related physical symptoms (r=-0.38, p<0.001). Partial correlations revealed that pre-post changes in rumination, unwanted intrusive thoughts, thought suppression, experiential avoidance, emotion suppression, and cognitive reappraisal each uniquely accounted for up to 32% of the correlation between the change in mindfulness and change in sleep disturbance and up to 30% of the correlation between the change in mindfulness and change in stress-related physical symptoms. Results suggest that the stress-reducing effects of MBSR are due, in part, to improvements in perseverative cognition and emotion regulation, two “transdiagnostic” mental processes that cut across stress-related disorders

Performance of Gonad Maturation and Spawned of Grouper Broodstock Cross Breeding Between F-2 and F-0

In fish grouper escpecially humpback grouper culture, seed and broodstock quality and availability determine the production success. Main supply of wild broodstock still dominates grouper hatchery activities, therefore, the exploitation of the wild broodstock is very high. Efforts to use the supply of cultured broodstock through selection and breeding processes will greatly determine their culture success. The purpose of this experiment was to get seeds from the cross breeding between F-2 and F-0. The research used two (2) concrete tanks with volume of 75 m3 each. Each tank was filled with 20 fishes consisting of 10 fishes of F-2 and 10 fishes of F-0. The experiment was conducted the Institute of Mariculture Research and Development, Gondol, Bali. The result showed a good gonadal development and natural spawning of cross breeding between F-2 and F-0. Total number of eggs (1.320.000) was found the highest in May in tank A, while the highest fertilized eggs of 385.000 were found in June. The SSCP analyses showed no difference in genetic characters of broodstock from cross-breeding between the female parent F-2 and F-0 male parent

Solar Assisted Heat Pump System for High Quality Drying Applications: A Critical Review

Solar assisted heat pump (SAHP) system integrates a solar thermal energy source with a heat pump. This technique is a very fundamental concept, especially for drying applications. By combining a solar thermal energy source such as solar thermal collectors and a heat pump dryer will assist in reducing the operation cost of drying and producing products with high quality. Many review papers in the literature evaluated the R&D aspects of solar-assisted heat pump dryers (SAHPD). This critical review paper studies some of the researches conducted in this field to understand and provides an update on recent developments in SAHPD. Also, a detailed explanation of principles and operation for SAHPD and its applications are presented. The used types of solar thermal collectors, as well as various heat pump dryers, are all discussed in this article. Finally, it is concluded that there is a clear lack of research in the techno-economic and environmental evaluation, while most of SAHPD studies focused on the performance study of the system

PRODUCTION OF FUNCTIONAL MALE BROODSTOCK OF CORAL TROUT GROUPER (Plectropomus leopardus)

Fertilization rate of the first generation of coral trout grouper, Plectropomus leopardus from wild broodstock in cultured tank was relatively low of 10-35%. Based on gonad histology analysis of 30 samples, only one male was found in early stage maturation. Therefore, it is needed to increase functional male production to ensure an increase level of egg fertilization. The experiment was conducted for 9 months using coral trout broodstock, from wild stock as control and selected F1 from culture as treatment. Broodstocks were reared in three tanks, each was 100 m3 in volume with 54 fishes/tank. All selected cultured fish (F1) in tank C were implanted with 17a-MT hormone at 50 mg/kg of body weight every month for 3 consecutive months. Wild stock fish in tank A and selected cultured fish (F1) in tank B were not implant as controls. The result showed that the number of male  increased 6 times in implanted by 17a-MT hormone compared to fish without implant only increased 2 times. Therefore, eggs fertilization and hatching rate were significantly increased by implanting F1 broodstocks with hormone17a-MT. Keywords: Functional male, broodstock, Coral trout (Plectropomus leopardus

KARAKTERISASITIGA LOKUSMIKROSATELITPADATELURDANLARVATUNASIRIP KUNING, Thunnus albacares = CHARACTERIZATION OF THREE MICROSATELLITE LOCI OF YELLOW FIN TUNA, Thunnus albacares EGGS AND LARVAE

Characterization of three microsatellite loci are able to provide information about genetic variation or polymorphism of yellow fin tuna eggs and larvae produced by domestication of broodstock. Thirty samples of eggs and larvae were collected from different spawning day and analyzed. Amplification of those three loci were carried out with multiflexing technique and electrophoreted ASI Prism 310 Genetic Analyzer sequencer. From those three loci were used (Ttho-1, Ttho-4 and Ttho-7) showed that locus Ttho-7 had higher genetic variance (0.720-1.212) compared to other loci. Based on the result, it can be concluded that high allele frequency as showed at Ttho-7 could be used as marker for a parental anal

Population density and territory size in juvenile rainbow trout, Oncorhynchus mykiss: implications for population regulation.

We manipulated population density of juvenile rainbow trout ( Oncorhynchus mykiss ) across a range of realistic densities in artificial stream channels, while controlling food abundance in two different ways: in Experiment 1, the total amount of food was held constant over a threefold increase in density, whereas in Experiment 2, the per capita amount of food was held constant over an eightfold increase in density. We tested the contrasting predictions that territory size (i) is not affected by population density; (ii) decreases with population density as 1/n, where n = the local population size; or (iii) decreases with population density but towards an asymptotic minimum size. In Experiment 1, territory size decreased with increasing population density. With the broader range of densities used in Experiment 2, territory size initially decreased with density and then leveled off at a minimum territory radius of 20–30 cm. Our results suggest an asymptotic minimum size of about 0.2 m2 for a 5 cm rainbow trout, similar to what is observed for high-density conditions in the wild. This minimum territory size could potentially set an upper limit on local population density and help regulate the population size of stream salmonids. </jats:p

Dynamic Resting-State Functional Connectivity in Major Depression

Major depressive disorder (MDD) is characterized by abnormal resting-state functional connectivity (RSFC), especially in medial prefrontal cortical (MPFC) regions of the default network. However, prior research in MDD has not examined dynamic changes in functional connectivity as networks form, interact, and dissolve over time. We compared unmedicated individuals with MDD (n=100) to control participants (n=109) on dynamic RSFC (operationalized as SD in RSFC over a series of sliding windows) of an MPFC seed region during a resting-state functional magnetic resonance imaging scan. Among participants with MDD, we also investigated the relationship between symptom severity and RSFC. Secondary analyses probed the association between dynamic RSFC and rumination. Results showed that individuals with MDD were characterized by decreased dynamic (less variable) RSFC between MPFC and regions of parahippocampal gyrus within the default network, a pattern related to sustained positive connectivity between these regions across sliding windows. In contrast, the MDD group exhibited increased dynamic (more variable) RSFC between MPFC and regions of insula, and higher severity of depression was related to increased dynamic RSFC between MPFC and dorsolateral prefrontal cortex. These patterns of highly variable RSFC were related to greater frequency of strong positive and negative correlations in activity across sliding windows. Secondary analyses indicated that increased dynamic RSFC between MPFC and insula was related to higher levels of recent rumination. These findings provide initial evidence that depression, and ruminative thinking in depression, are related to abnormal patterns of fluctuating communication among brain systems involved in regulating attention and self-referential thinking

Interaction of the Psychiatric Risk Gene Cacna1c With Post-weaning Social Isolation or Environmental Enrichment Does Not Affect Brain Mitochondrial Bioenergetics in Rats

The pathophysiology of neuropsychiatric disorders involves complex interactions between genetic and environmental risk factors. Confirmed by several genome-wide association studies, Cacna1c represents one of the most robustly replicated psychiatric risk genes. Besides genetic predispositions, environmental stress such as childhood maltreatment also contributes to enhanced disease vulnerability. Both, Cacna1c gene variants and stressful life events are associated with morphological alterations in the prefrontal cortex and the hippocampus. Emerging evidence suggests impaired mitochondrial bioenergetics as a possible underlying mechanism of these regional brain abnormalities. In the present study, we simulated the interaction of psychiatric disease-relevant genetic and environmental factors in rodents to investigate their potential effect on brain mitochondrial function using a constitutive heterozygous Cacna1c rat model in combination with a four-week exposure to either post-weaning social isolation, standard housing, or social and physical environmental enrichment. Mitochondria were isolated from the prefrontal cortex and the hippocampus to evaluate their bioenergetics, membrane potential, reactive oxygen species production, and respiratory chain complex protein levels. None of these parameters were considerably affected in this particular gene-environment setting. These negative results were very robust in all tested conditions demonstrating that Cacna1c depletion did not significantly translate into altered bioenergetic characteristics. Thus, further investigations are required to determine the disease-related effects on brain mitochondria