Study of Wingtip Vortex Characteristics in the Far-Field of a NACA 0015 Airfoil

A study of wingtip vortices is currently underway in Utah State University\u27s 4-ft. x 4-ft. subsonic wind tunnel on a NACA 0015 rectangular wing section. The purpose of this study is to investigate the characteristics of the flow field, which govern the size, the structure, and the oscillatory motion of the vortex core. These characteristics can be obtained by collecting and analyzing accurate velocity measurements at several locations downstream of the wingtip for different Reynolds numbers and angles-of-attack. One triple-sensor and two single-sensor hot wire probes are used to collect the data. The axial velocity profiles generated from the data will help determine how the Reynolds number and angle-of-attack modifies the structure of the vortex core and the conditions that cause it to transition from a wake-liken to a jet-like profile. In addition, the tangential velocity profiles will help determine the effects Reynolds number and angle-of-attack have on the size and strength of the vortex core. In addition, a database of vortex characteristics for varying experimental parameters will be established that will help identify consistent trends in vortex behavior and lead to a better understanding of the governing physics. This database will be used by colleagues to validate and improve their computational algorithms

Public or private religiosity: which Is protective for adolescent substance use and by what pathways?

While it is well understood that adolescent religiosity is associated with the use and abuse of licit and illicit substances, few studies have revealed the pathways through which religiosity buffers youth against involvement in such behavior. The aim of this study is to examine the complexity of the relationships between religiosity, sensation seeking, injunctive norms, and adolescent substance use. Using a national sample of adolescents (N = 18,614), negative binomial regression and path analysis were used to examine the various components of the relationship between religiosity and the use of cigarettes, alcohol, and marijuana. Results indicate that private religiosity moderates the relationship between key risk factors and substance use. Public and private religiosity were associated with tolerant injunctive substance use norms which, in turn, were associated with substance use. Implications for research and theory related to religiosity and adolescent substance use are discussed

Biomass Torrefaction Process Review and Moving Bed Torrefaction System Model Development

Torrefaction is currently developing as an important preprocessing step to improve the quality of biomass in terms of physical properties, and proximate and ultimate composition. Torrefaction is a slow heating of biomass in an inert or reduced environment to a maximum temperature of 300°C. Torrefaction can also be defined as a group of products resulting from the partially controlled and isothermal pyrolysis of biomass occurring in a temperature range of 200–230ºC and 270–280ºC. Thus, the process can also be called a mild pyrolysis as it occurs at the lower temperature range of the pyrolysis process. At the end of the torrefaction process, a solid uniform product with lower moisture content and higher energy content than raw biomass is produced. Most of the smoke-producing compounds and other volatiles are removed during torrefaction, producing a final product that will have a lower mass but a higher heating value. An important aspect of research is to establish a degree of torrefaction where gains in heating value offset the loss of mass. There is a lack of literature on torrefaction reactor designs and a design sheet for estimating the dimensions of the torrefier based on capacity. This study includes a) conducting a detailed review on the torrefaction of biomass in terms of understanding the process, product properties, off-gas compositions, and methods used, and b) to design a moving bed torrefier, taking into account the basic fundamental heat and mass transfer calculations. Specific objectives include calculating the dimensions like diameter and height of the moving packed bed for different capacities, designing the heat loads and gas flow rates, and developing an interactive excel sheet where the user can define design specifications. In this report, 25–1000 kg/hr are used in equations for the design of the torrefier, examples of calculations, and specifications for the torrefier

Value of Distributed Preprocessing of Biomass Feedstocks to a Bioenergy Industry

Biomass preprocessing is one of the primary operations in the feedstock assembly system and the front-end of a biorefinery. Its purpose is to chop, grind, or otherwise format the biomass into a suitable feedstock for conversion to ethanol and other bioproducts. Many variables such as equipment cost and efficiency, and feedstock moisture content, particle size, bulk density, compressibility, and flowability affect the location and implementation of this unit operation. Previous conceptual designs show this operation to be located at the front-end of the biorefinery. However, data are presented that show distributed preprocessing at the field-side or in a fixed preprocessing facility can provide significant cost benefits by producing a higher value feedstock with improved handling, transporting, and merchandising potential. In addition, data supporting the preferential deconstruction of feedstock materials due to their bio-composite structure identifies the potential for significant improvements in equipment efficiencies and compositional quality upgrades. Theses data are collected from full-scale low and high capacity hammermill grinders with various screen sizes. Multiple feedstock varieties with a range of moisture values were used in the preprocessing tests. The comparative values of the different grinding configurations, feedstock varieties, and moisture levels are assessed through post-grinding analysis of the different particle fractions separated with a medium-scale forage particle separator and a Rototap separator. The results show that distributed preprocessing produces a material that has bulk flowable properties and fractionation benefits that can improve the ease of transporting, handling and conveying the material to the biorefinery and improve the biochemical and thermochemical conversion processes

Quiet Eye: The efficiency paradox – comment on Vickers

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Femoroacetabular Impingement as a Complication of Acetabular Fracture Fixation

Case We present the case of a thirteen-year-old female who sustained a posterior wall acetabular fracture dislocation. She underwent urgent closed reduction and subsequent uncomplicated open reduction and internal fixation. Post reduction computed tomography demonstrated a concentrically reduced hip joint with no evidence of femoroacetabular impingement (FAI). She subsequently healed her fracture and returned to running activities; however, one year later presented with aching pain in her thigh. Radiographs demonstrated the development of a large osseous prominence on her anterolateral femoral neck consistent with femoroacetabular impingement. Based on these findings she was evaluated by a hip preservation specialist. She subsequently underwent successful hip arthroscopy for labral repair and femoral osteochondroplasty. She was eventually able to return to running sports with little pain. Summary We present a case of FAI presenting as a complication of acetabular fracture fixation. This should be discussed with patients presenting with traumatic hip dislocations as a possible complication of surgical fixation or possibly of the injury itself

CBTL Design Case Summary Conventional Feedstock Supply System - Herbaceous

A conventional bale feedstock design has been established that represents supply system technologies, costs, and logistics that are achievable today for supplying herbaceous feedstocks as a blendstock with coal for energy production. Efforts are made to identify bottlenecks and optimize the efficiency and capacities of this supply system, within the constraints of existing local feedstock supplies, equipment, and permitting requirements. The feedstock supply system logistics operations encompass all of the activities necessary to move herbaceous biomass feedstock from the production location to the conversion reactor ready for blending and insertion. This supply system includes operations that are currently available such that costs and logistics are reasonable and reliable. The system modeled for this research project includes the uses of field-dried corn stover or switchgrass as a feedstock to annually supply an 800,000 DM ton conversion facility