4,646 research outputs found
Serrated trailing edges for improving lift and drag characteristics of lifting surfaces
An improvement in the lift and drag characteristics of a lifting surface is achieved by attaching a serrated panel to the trailing edge of the lifting surface. The serrations may have a saw-tooth configuration, with a 60 degree included angle between adjacent serrations. The serrations may vary in shape and size over the span-wise length of the lifting surface, and may be positioned at fixed or adjustable deflections relative to the chord of the lifting surface
Utilization of Agro-based Adsorbents in Binary Wastewater Treatment
The application of agro-based adsorbents is growing in the tertiary stage of the wastewater treatment process during the presence of hazardous pollutants. Dye and coffee industries are among the major wastewater pollutant sources negatively affect aquatic ecosystems and human health. The current study attempts to treat a binary mixture of crystal violet (CV) and coffee wastewater using agro-based adsorbents such as peanut hull and onion peel. The performance and efficacy of low-cost adsorbents were evaluated using parameters, including transmittance and non-purgeable organic carbon (NPOC). Batch adsorption studies were conducted to optimize both the adsorbent size and dosage that affect the treatment process. The experimental data obtained from the experiment were analyzed to understand whether Langmuir or Freundlich best fits the treatment process\u27s experimental data. It was observed that Langmuir isotherm seems to fit experimental data using peanut hull and Freundlich isotherm using onion peel. The kinetics of the adsorption process appears to follow the pseudo-first-order kinetic model. The regression coefficient value of onion peel was 0.91, and uptake was 58.14 mg/g. Similarly, using the peanut hull, the regression coefficient was 0.99, and uptake was 57.47 mg/g. It seems that peanut hull appears to perform better as a low-cost adsorbent compared to onion peel. The adsorption capacity increased with the increasing dosage of low-cost adsorbent (peanut hull) until the adsorbent size of 0.6-0.425 mm and steadily decreased after that
Treatment of Disperse Blue 14 Wastewater and Sugar Wastewater By Low Cost Adsorbents
Orange peel and Peanut hull are used in this research to treat the combined binary mixture of Disperse Blue 14and sugar wastewater. The combined wastewater is treated with adsorption followed by micro-filtration. The dosages, sizes and concentrations used in this research are based on trail and error method. Whatman-41 is used in the micro-filtration treatment process. This research is mainly based on color removal. The color removal is estimated and compared from the measured transmittance and absorbance values. The same treatment tests are performed on the activated carbon and taken as datum and compared with the low-cost adsorbents. NPOC values were also estimated using Shimadzu TOCL analyzer which followed catalytic oxidation method. Finally, the data is analyzed with Langmuir and Freundlich isotherm equations
Investigation of the Liquid Fluorine-liquid Diborane Propellant Combination in a 100-pound-thrust Rocket Engine
The experimental performance of liquid fluorine and liquid diborane was investigated in a 100-pound-thrust engine at a combustion pressure of 300 pounds per square inch absolute. Methods of handling and transporting liquid fluorine were developed. It was extremely difficult to obtain satisfactory operation because of the high flame speed and high combustion chamber temperatures. The maximum performance obtained was 280 pound seconds per pound, 88 percent of the theoretical maximum. The theoretical performance was recalculated with revised thermodynamic data, indicating a maximum specific impulse of 311 pound seconds per pound as compared with the previously reported value of 323
The role of reward and reward uncertainty in episodic memory
Declarative memory has been found to be sensitive to reward-related changes in the environment. The reward signal can be broken down into information regarding the expected value of the reward, reward uncertainty and the prediction error. Research has established that high as opposed to low reward values enhance declarative memory. Research in neuroscience suggests that high uncertainty activates the reward system, which could lead to enhanced learning and memory. Here we present the results of four behavioural experiments that examined the role of reward uncertainty in memory, independently from any other theoretically motivated reward-related effects. Participants completed motivated word learn- ing tasks in which we varied the level of reward uncertainty and magnitude. Rewards were dependent upon memory performance in a delayed recognition test. Overall the results suggest that reward uncer- tainty does not affect episodic memory. Instead, only reward outcome appears to play a major role in modulating episodic memory
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Prevalence of iron deficiency in 62,685 women of seven race/ethnicity groups: The HEIRS Study.
BackgroundFew cross-sectional studies report iron deficiency (ID) prevalence in women of different race/ethnicity and ages in US or Canada.Materials and methodsWe evaluated screening observations on women who participated between 2001-2003 in a cross-sectional, primary care-based sample of adults ages ≥25 y whose observations were complete: race/ethnicity; age; transferrin saturation; serum ferritin; and HFE p.C282Y and p.H63D alleles. We defined ID using a stringent criterion: combined transferrin saturation <10% and serum ferritin <33.7 pmol/L (<15 μg/L). We compared ID prevalence in women of different race/ethnicity subgrouped by age and determined associations of p.C282Y and p.H63D to ID overall, and to ID in women ages 25-44 y with or without self-reported pregnancy.ResultsThese 62,685 women included 27,079 whites, 17,272 blacks, 8,566 Hispanics, 7,615 Asians, 449 Pacific Islanders, 441 Native Americans, and 1,263 participants of other race/ethnicity. Proportions of women with ID were higher in Hispanics and blacks than whites and Asians. Prevalence of ID was significantly greater in women ages 25-54 y of all race/ethnicity groups than women ages ≥55 y of corresponding race/ethnicity. In women ages ≥55 y, ID prevalence did not differ significantly across race/ethnicity. p.C282Y and p.H63D prevalence did not differ significantly in women with or without ID, regardless of race/ethnicity, age subgroup, or pregnancy.ConclusionsID prevalence was greater in Hispanic and black than white and Asian women ages 25-54 y. p.C282Y and p.H63D prevalence did not differ significantly in women with or without ID, regardless of race/ethnicity, age subgroup, or pregnancy
Teaching Innovation as Part of an Agribusiness Curriculum
Innovation is critical to the survival of agricultural businesses in the U.S. yet few universities have classes in their curricula that focus on innovation and innovation management. Innovation includes developing new processes and concepts and taking products based on those ideas to market. By its nature, innovation generally involves technical components, market assessment, business analysis, and implementation strategies that include marketing campaigns to a target market. As a result, if innovation is going to be experientially taught to students, the class will likely need to include concepts from multiple disciplines. The objectives of this paper are to present an outline of capstone/senior design classes designed to cause students to learn innovation by participating in interdisciplinary teams working with real companies on the development of new product innovation.Teaching/Communication/Extension/Profession,
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Direct iminization of PEEK
Semi-crystalline poly(ether ketone)s are important high-temperature engineering thermoplastics, but are difficult to characterize at the molecular level because of their insolubility in conventional organic solvents. Here we report that polymers of this type, including PEEK, react cleanly at high temperatures with low-volatility aralkyl amines to afford stable, noncrystalline poly(ether-imine)s, which are readily soluble in solvents such as chloroform, THF and DMF and so characterizable by conventional size-exclusion chromatography
Structural basis of Lewis(b) antigen binding by the Helicobacter pylori adhesin BabA
Helicobacter pylori is a leading cause of peptic ulceration and gastric cancer worldwide. To achieve colonization of the stomach, this Gram-negative bacterium adheres to Lewis(b) (Le(b)) antigens in the gastric mucosa using its outer membrane protein BabA. Structural information for BabA has been elusive, and thus, its molecular mechanism for recognizing Le(b) antigens remains unknown. We present the crystal structure of the extracellular domain of BabA, from H. pylori strain J99, in the absence and presence of Le(b) at 2.0- and 2.1-Å resolutions, respectively. BabA is a predominantly α-helical molecule with a markedly kinked tertiary structure containing a single, shallow Le(b) binding site at its tip within a β-strand motif. No conformational change occurs in BabA upon binding of Le(b), which is characterized by low affinity under acidic [K D (dissociation constant) of ~227 μM] and neutral (K D of ~252 μM) conditions. Binding is mediated by a network of hydrogen bonds between Le(b) Fuc1, GlcNAc3, Fuc4, and Gal5 residues and a total of eight BabA amino acids (C189, G191, N194, N206, D233, S234, S244, and T246) through both carbonyl backbone and side-chain interactions. The structural model was validated through the generation of two BabA variants containing N206A and combined D233A/S244A substitutions, which result in a reduction and complete loss of binding affinity to Le(b), respectively. Knowledge of the molecular basis of Le(b) recognition by BabA provides a platform for the development of therapeutics targeted at inhibiting H. pylori adherence to the gastric mucosa
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