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Hydrokinetic arrays, or farms, offer a promising solution to the global energy crisis by enabling cost-effective and environmentally friendly energy generation in locations with water flows. This paper presents research focused on the design and optimization of a Gorlov-type vertical-axis hydrokinetic turbine array for power generation. The study involved (i) numerical simulations using computational fluid dynamics (CFD) software with the six degrees of freedom (6DoF) tool, (ii) optimization techniques such as response surface methodology, and (iii) experimental testing in natural environments. The objective was to develop an efficient system with low manufacturing and maintenance costs. A key finding was that the separation distance between rotors, both along and across the fluid flow, is a critical parameter in designing hydrokinetic arrays. For this study, a triangular array configuration, termed Triframe, was used, consisting of three Gorlov-type turbines with four blades each. The optimization process led to separation distances based on the diameter (D) of the turbines, with 15.9672D along the fluid flow (X) and 4.15719D across the flow (Y). Finally, an experimental scale model of the hydrokinetic array was successfully constructed and characterized, demonstrating the effectiveness of the optimization process described in this study. [ABSTRACT FROM AUTHOR]

The growing global energy demand necessitates a shift towards sustainable sources to mitigate environmental issues and ensure energy security. This work explores the design and optimization of propeller-type hydrokinetic turbines to efficiently harness renewable energy from water currents. Through experimental testing and regression modeling, the research aimed to maximize the power coefficient ( C p ) by determining the optimal values of the number of blades (Z) and the turbine diameter to hub diameter ratio ( d / D ). By correcting for experimental biases, the study elucidates the importance of factors such as the blockage ratio and turbine configuration on its performance. A second-order polynomial regression model, which was validated through analysis of variance, determined that when Z and d / D were set at 4 and 0.15, respectively, the optimal value for Cp was 53.62%. These findings provide valuable insights for optimizing hydrokinetic turbine efficiency, contributing to the advancement of renewable energy technologies. [ABSTRACT FROM AUTHOR]

This work compared the suitability of the k- ϵ standard, k- ϵ RNG, k- ω SST, and k- ω standard turbulence models for simulating a gravitational water vortex hydraulic turbine using ANSYS Fluent. This study revealed significant discrepancies between the models, particularly in predicting vortex circulation. While the k- ϵ RNG and standard k- ω models maintained relatively constant circulation values, the k- ϵ standard model exhibited higher values, and the k- ω SST model showed irregular fluctuations. The mass flow rate stabilization also varied, with the k- ϵ RNG, k- ω SST, and k- ω standard models being stabilized around 2.1 kg/s, whereas the k- ϵ standard model fluctuated between 1.9 and 2.1 kg/s. Statistical analyses, including ANOVA and multiple comparison methods, confirmed the significant impact of the turbulence model choice on both the circulation and mass flow rate. Experimental validation further supported the numerical findings by demonstrating that the k- ω shear stress transport (SST) model most closely matched the real vortex profile, followed by the k- ϵ RNG model. The primary contribution of this work is the comprehensive evaluation of these turbulence models, which provide clear guidance on their applicability to gravitational water vortex hydraulic turbine simulations. [ABSTRACT FROM AUTHOR]

In this work, an experimental analysis of the performance of a cross-flow turbine, commonly referred to as a Michell–Banki turbine (MBT), is carried out for small-scale hydropower production in rural areas located in developing countries to support their social and economic development activities. The study investigates how the efficiency of the MBT is influenced by the presence or absence of a nozzle, along with variations in the internal guide vane (GV) and its angle. The runner had 26 blades that were arranged symmetrically in the periphery between two circular plates. The designed MBT had the ability to generate a maximum of 100 W of power at a water flow rate and a head of 0.009 m3/s and 0.6311 m, respectively. The experimental tests were carried out using a hydraulic bench. The turbine efficiency without the inner GV was found to be higher than that of the turbine with the inner GV; i.e., it was found that the utilization of the GV did not enhance the efficiency of the MBT due to the occurrence of a choking effect. A maximum hydraulic efficiency of 85% was achieved in the turbine without an inner GV in comparison with the efficiency achieved (77%) with this device and an optimum opening angle of the GV of 24° (75% of opening). In this regard, the GV design should be carefully carried out to improve the MBT efficiency. Additionally, the effect of the GV shape on the MBT performance should be experimentally investigated to obtain a more general judgment regarding the role of this device. [ABSTRACT FROM AUTHOR]

Copyright of Revista Lasallista de Investigación is the property of Corporacion Universitaria Lasallista and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Hallazgos: Revista de Investigaciones is the property of Ediciones USTA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Monomeric, dimeric, palindromic, and tetrameric peptides derived from bovine lactoferricin (LfcinB) containing the RRWQWR or the KKWQWK sequence were synthesized via SPPS- Fmoc/tBu strategy, and Lys-peptides showed higher synthesis efficiency. The antibacterial activity of the peptides against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus ATCC reference strains and a multidrug resistant clinical isolate was evaluated. Lys peptides exhibited similar antibacterial activity to the Arg peptides, suggesting that the Arg for Lys substitution does not significantly affect the antibacterial activity. The synergy assays showed that the covalent dimeric Lys peptide decreased the MIC value of the ciprofloxacin up to 32 times, and LfcinB (20-25), and one of the Lys-peptides [K]-LfcinB (20-25)Pal presented a synergistic effect. Additionally, Lys peptides lowered the hemolytic activity by 2 to 7 times. These results suggest that short peptides derived from Lys-LfcinB could be a cost-effective alternative for the development of drugs or combinatory treatments against bacterial infections. [ABSTRACT FROM AUTHOR]

A chimeric peptide derived from Lactoferricin B (LfcinB) and Buforin II (BFII) was designed. It specifically contains the reported antimicrobial minimal motif sequences LfcinB (20–25): RRWQWR and BFII (32–35): RLLR. The chimeric peptide was synthesized by intramolecular cyclization with a triazole bridge. The Chimera 3 exhibited higher antimicrobial activity against E. coli ATCC 25922 (MIC 93 μM) and S. aureus ATCC 25923 (93 μM) than the original sequences. Furthermore, it did not exhibit a significant hemolytic effect. [ABSTRACT FROM AUTHOR]

Background Food protein-induced enterocolitis ( FPIES) is an uncommon, non-IgE-mediated food allergy that usually debuts in infancy with profuse vomiting, lethargy, and pallor 2-4 h following ingestion of the offending food. Its immune mechanism is not known. We aimed to describe the clinical features and outcome of children with fish- FPIES as well as to investigate on cellular immune response implicated. Methods Prospective and follow-up clinical study of children with FPIES by fish over a period between 2004 and 2013 was conducted. Measurement in vitro of both cytokine production in peripheral blood mononuclear cells ( PBMCs) and expression of HLA- DR in monocyte-derived dendritic cells stimulated with fish extracts. Results Sixteen children (seven male and nine female) were included, with a mean age of onset at 10 months. Diagnosis was established after a median of 4 reactions. Twelve patients were treated in emergency room, and two were admitted in intensive care. Patch tests were positive in six patients. Skin prick tests ( SPTs) and specific IgE to all fish tested were negative. Only three children reached tolerance at a mean age of 4.5 years. Eight children avoided fish because of positive oral food challenge ( OFC) after 6 years of age. Other patients have not been challenged because of parent refusal to OFC or a recent diagnosis. TNF-α was increased in patients, and a significant elevation of the HLA- DR marker was also observed in these patients vs. control donors. Conclusions FPIES caused by fish in many cases presents with severe clinical manifestations. Patch test has poor diagnostic value, and OFC is the gold standard to test tolerance. The cytokine TNF-α may be implicated in the clinical symptoms. Higher expression of HLA- DR in dendritic cells has also been detected in our patients. [ABSTRACT FROM AUTHOR]

Thrombocytopenia is defined as a platelet count of less than 100,000 platelets per microlitre (mcL). Thrombocytopenia develops in approximately 6-7% of women during pregnancy and at least 3% of these cases are caused by immunological platelet destruction. Herein, we present a pregnant woman who develops at the first trimester autoimmune thrombocytopenia purpura associated with positive antiphospholipid antibodies. The disease was refractory to pharmacological treatments but had a favourable response to splenectomy. The patient carried the pregnancy to term without complication and gave birth to a healthy baby girl. [ABSTRACT FROM AUTHOR]

Thrombocytopenia is defined as a platelet count of less than 100,000 platelets per microlitre (mcL). Thrombocytopenia develops in approximately 6-7% of women during pregnancy and at least 3% of these cases are caused by immunological platelet destruction. Herein, we present a pregnant woman who develops at the first trimester autoimmune thrombocytopenia purpura associated with positive antiphospholipid antibodies. The disease was refractory to pharmacological treatments but had a favourable response to splenectomy. The patient carried the pregnancy to term without complication and gave birth to a healthy baby girl. [ABSTRACT FROM AUTHOR]

Copyright of Psicogente is the property of Universidad Simon Bolivar, Programa de Psicologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)