The Very Low Head Turbine for hydropower generation in existing hydraulic infrastructures: State of the art and future challenges

The Very Low Head turbine (VLHT) is an axial flow turbine developed for heads below 4.5 m and flow rates up to 30 m3/s. In this work, the state of the art, the technological advancements and the scientific gaps were discussed and generalized, with a special focus on design, ecological behavior, costs, performance at different flows, heads and rotational speeds. The flow field and the hydraulic behavior under different configurations (e.g. in presence of cavitation and with an upstream obstacle) were described, with the aim of deriving engineering suggestions. Results of ecological tests were generalized (fish survival rate is more than 90%) by using the blade strike model, proposing an expeditious method for a preliminary appraisal of the ecological impact on downstream migrating fish. Despite the hundreds of installations worldwide, especially in existing barriers, some scientific gaps need to be better addressed yet, e.g., the influence of the number of blades and axis inclination on the efficiency, the influence of flow, head and rotational speed on the flow field and a quantification of the head losses through the trash rack above the runner

Effects of Two Halophytic Plants (Kochia and Atriplex) on Digestibility, Fermentation and Protein Synthesis by Ruminal Microbes Maintained in Continuous Culture

Eight continuous culture fermenters were used in a completely randomized design to evaluate various nutritional values of Kochia (Kochia scoparia) compared with Atriplex (Atriplex dimorphostegia). Dried and pelleted samples (leaves and stems) provided substrate for metabolism by ruminal microbes maintained in a continuous culture fermentation system. Results indicated that there were no differences (p>0.05) in dry matter (DM) and crude protein (CP) digestibility between the two halophytic plants. Atriplex had higher (p0.05) between the two halophytic plants in molar proportion of acetate and propionate, but the concentration of butyrate and valerate in Kochia were about two fold of Atriplex (p<0.05). When Kochia provided substrate to the microbes, protein synthesis was higher (p<0.05) compared with feeding Atriplex (5.96 vs. 4.85 g N/kg of OM truly digested). It was concluded that Kochia scoparia and Atriplex dimorphostegia had similar digestibility of DM and CP. It appears that these halophytic plants may not have enough digestible energy for high producing ruminants

Estimate of Inbreeding Coefficient and Its Effects on Reproductive Traits of Dairy Herds in Isfahan Province

This study was carried out to study the inbreeding coefficient and its effect on reproductive performance of dairy cows (age at first calving, calving interval and open days) in Isfahan province. Records of 31,977 (primiparous cows), 36,982 and 51,423 (multiparous cows) for age at first calving, calving interval and open days were used, respectively. The inbreeding coefficients of animals were calculated using pedigree information of 78,425 females and 8,056 males, which were born from 1963 to 2009. The overall mean and maximum inbreeding coefficients in Holstein cows were 2.33% and 31.30%, respectively. The results showed that 57,234 animals were inbred with 3.57% inbreeding coefficient. Regression coefficients on inbreeding coefficient for age at first calving, calving interval and open days were 0.589±0.21, 1.08±0.15 and 0.27±12, respectively. Estimated inbreeding indicated significantly negative effect on the reproductive traits in different parturition periods. The results revealed that the average inbreeding trend was increased in the dairy herds. The increased inbreeding was due to close mating systems between the candidates, and it showed negative effects on the reproductive traits in Isfahan dairy herds

Effect of Intermittent Training on Oxidative and Glycolytic Capacity in Rat Skeletal Muscles

Introduction: Any type of exercise protocol has specific effects on the physiology of the body. Thus, according to the purpose of the training program and conditions of the subjects, a specific exercise protocol is needed to be considered. Therefore, the purpose of this study was to assess the effect of intermittent training on oxidative and glycolytic capacity in rat skeletal muscles. Methods: Forty male rats were divided into two old (27 mon, 389±31 g) and young groups (3 ± 4 mon, 224±14 g), each of which were randomly divided into control and experimental groups (n = 10). Training group performed intermittent exercise on a treadmill 6 times /week for 8weeks. It consisted of 10 bouts of 4 min running interspersed by 2 min of active rest. All rats were anesthetized, 24 hours after the last session exercise, and Soleus (SOL) and extensor digitorumlongus (EDL) muscles were removed rapidly. In fact, the tissues were analyzed in regard with CS and LDH enzymes activities. In order to analyze the study data, one way-ANOVA and Tukey's post-hoc tests were applied. Results: The results demonstrated that CS enzyme activity in EDL and SOL muscles increased significantly in both, old (OT) and young groups (YT) (p 0.05). Conclusion: The results suggested that the training method described in the present study can be quite beneficial to the young and old, when a simultaneous increase in oxidative and glycolytic capacity is aimed

Effects of Sowing Date and Plant Density on Yield and Yield Components of Grass Pea (Lathyrus sativus L.) in Birjand Region

Grass pea (Lathyrus sativus L.) is a crop which could substitute soybean in poultry ration in arid and semi-arid regions. To investigate the effects of sowing date and plant density on yield and yield components of grass pea, a factorial experiment based on randomized complete blocks design with four replications was conducted at Research Farm of Faculty of Agriculture, University of Birjand in 2008. Treatments included three sowing dates (March 5, March 21 and April 4) and four plant densities (30, 40, 50 and 60 plants per m2). Number of pods per plant, number of seeds per pod, number of seeds per plant, 100-seed weight, seed yield, biological yield and harvest index were measured. Results showed that by delaying the planting date, number of pods per plant, number of seeds per plant, seed yield and biological yield were decreased significantly. Maximum seed yield (2524 kg/ha) was achieved at the early sowing date (5th of March). These traits were increased with increasing plant density up to 50 plants per m2. But, increasing the plant density to 60 plants per m2 caused a decrease of these characteristics. Different planting dates and densities did not show any significant changes in number of seeds per pod, 100-seed weight and harvest index. Based on these results and the fact that Birjand is overwhelmed by an arid climate, planting grass pea at the first possible date at the end of winter with a moderate planting density (50 plants per m2) can lead to a reasonable seed yield