Use of a liquid-crystal, heater-element composite for quantitative, high-resolution heat transfer coefficients on a turbine airfoil, including turbulence and surface roughness effects

Local heat transfer coefficients were measured along the midchord of a three-times-size turbine vane airfoil in a static cascade operated at roon temperature over a range of Reynolds numbers. The test surface consisted of a composite of commercially available materials: a Mylar sheet with a layer of cholestric liquid crystals, which change color with temperature, and a heater made of a polyester sheet coated with vapor-deposited gold, which produces uniform heat flux. After the initial selection and calibration of the composite sheet, accurate, quantitative, and continuous heat transfer coefficients were mapped over the airfoil surface. Tests were conducted at two free-stream turbulence intensities: 0.6 percent, which is typical of wind tunnels; and 10 percent, which is typical of real engine conditions. In addition to a smooth airfoil, the effects of local leading-edge sand roughness were also examined for a value greater than the critical roughness. The local heat transfer coefficients are presented for both free-stream turbulence intensities for inlet Reynolds numbers from 1.20 to 5.55 x 10 to the 5th power. Comparisons are also made with analytical values of heat transfer coefficients obtained from the STAN5 boundary layer code

Exploring factors of english language program designs for aircraft maintenance technicians (AMTs) in Colombia: a case study

The current qualitative case study explores the factors of English language programs curriculum designs for Aircraft Maintenance Technicians (AMTs) in Colombia that might suggest adjusting or standardizing. The notion is extremely relevant since AMTs will almost always have to cope with aviation documentation in English at their workplaces, as more Colombian airline companies and airports require the ability to communicate clearly and effectively in English. Fifty-nine aviation students, 71 professionals, and five language teachers participated. Moreover, 15 different aviation programs were analyzed. Student and professional questionnaires, teacher interviews, and a comparison matrix were used to collect data for this study. Results indicate program curricular discrepancies, a need for multiple approaches for students, and a necessity for coordination between language and aviation professionals. The findings highlight the importance of customizing the English curriculum for AMTs students. Future implications include presenting and channeling the findings through the aviation authority in Colombia, Aerocivil, to establish new linguistic guidelines for all aviation schools that offer maintenance programs promoting better communication in English.MaestríaMagister en la Enseñanza del Ingle

Independence at Risk: Older Californians With Disabilities Struggle to Remain at Home as Public Supports Shrink

Presents findings about aging Californians with disabilities who depend on paid public programs and unpaid help to live at home. Makes policy recommendations, including consolidating long-term care programs and enhancing support for caregivers

The invertebrate Caenorhabditis elegans biosynthesizes ascorbate.

l-Ascorbate, commonly known as vitamin C, serves as an antioxidant and cofactor essential for many biological processes. Distinct ascorbate biosynthetic pathways have been established for animals and plants, but little is known about the presence or synthesis of this molecule in invertebrate species. We have investigated ascorbate metabolism in the nematode Caenorhabditis elegans, where this molecule would be expected to play roles in oxidative stress resistance and as cofactor in collagen and neurotransmitter synthesis. Using high-performance liquid chromatography and gas-chromatography mass spectrometry, we determined that ascorbate is present at low amounts in the egg stage, L1 larvae, and mixed animal populations, with the egg stage containing the highest concentrations. Incubating C. elegans with precursor molecules necessary for ascorbate synthesis in plants and animals did not significantly alter ascorbate levels. Furthermore, bioinformatic analyses did not support the presence in C. elegans of either the plant or the animal biosynthetic pathway. However, we observed the complete (13)C-labeling of ascorbate when C. elegans was grown with (13)C-labeled Escherichia coli as a food source. These results support the hypothesis that ascorbate biosynthesis in invertebrates may proceed by a novel pathway and lay the foundation for a broader understanding of its biological role

Diseño de una mezcla asfáltica convencional y reciclado con 100% de RAP

Trabajo de InvestigaciónEl trabajo de investigación se realizó a partir de dos (2) muestras: una con 100% RAP y la otra sustituyéndose el material grueso por RAP, elaborándose cuatro (4) tipos de dosificaciones con cemento asfáltico 60/70 (2.5%, 3%, 3.5%, 4%). Por cada dosificación se fabricaron tres (3) probetas en donde a cada una de estas se le realizaron ensayos de laboratorio según la norma INV-E- 786-131.INTRODUCCIÓN 2.ANTECEDENTES Y JUSTIFICACIÓN. 3.PLANTEAMIENTO Y FORMULACIÓN DEL PROBLEMA. 4. OBJETIVOS 5.ALCANCES Y LIMITACIONES. 6.MARCO DE REFERENCIA 7.METODOLOGÍA 8.RESULTADOS Y ANÁLISIS 9.CONCLUSIONES 10.REFERENTES BIBLIOGRÁFICOSPregradoIngeniero Civi