1,708 research outputs found

    Steep gravity–capillary waves within the internal resonance regime

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    Steep gravity–capillary waves are studied experimentally in a channel. The range of cyclic frequencies investigated is 6.94–9.80 Hz; namely, the high‐frequency portion of the regime of internal resonances according to the weakly nonlinear theory (Wilton’s ripples). These wave trains are stable according to the nonlinear Schrödinger equation. The experimental wave trains are generated by large, sinusoidal oscillations of the wavemaker. A comparison is made between the measured wave fields and the (symmetric) numerical solutions of Schwartz and Vanden‐Broeck [J. Fluid Mech. 95, 119 (1979)], Chen and Saffman [Stud. Appl. Math. 60, 183 (1979); 62, 95 (1980)], and Huh (Ph.D. dissertation, University of Michigan, 1991). The waves are shown to be of slightly varying asymmetry as they propagate downstream. Their symmetric parts, isolated by determining the phase which provides the smallest mean‐square antisymmetric part, compare favorably with the ‘‘gravity‐type’’ wave solutions determined by numerical computations. The antisymmetric part of the wave profile is always less than 30% of the peak‐to‐peak height of the symmetric part. As nonlinearity is increased, the amplitudes of the short‐wave undulations in the trough of the primary wave increase; however, there are no significant changes in these short‐wave frequencies. The lowest frequency primary‐wave experiments, which generate the highest frequency short‐wave undulations, exhibit more rapid viscous decay of these high‐frequency waves than do the higher‐frequency primary wave experiments.  Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69701/2/PFADEB-4-11-2466-1.pd

    Response and Discrimination Performance of Arrays of Organothiol-Capped Au Nanoparticle Chemiresistive Vapor Sensors

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    The response and discrimination performance of an array that consisted of 20 different organothiol-capped Au nanoparticle chemiresistive vapor sensors was evaluated during exposure to 13 different organic vapors. The passivating organothiol ligand library consisted of collections of straight-chain alkanethiols, branched alkanethiols, and aromatic thiols. A fourth collection of sensors was formed from composites of 2-phenylethanethiol-capped Au nanoparticles and nonpolymeric aromatic materials that were coembedded in a sensor film. The organic vapors consisted of six hydrocarbons (n-hexane, n-heptane, n-octane, isooctane, cyclohexane, and toluene), three polar aprotic vapors (chloroform, tetrahydrofuran, and ethyl acetate), and four alcohols (methanol, ethanol, isopropanol, and 1-butanol). Trends in the resistance response of the sensors were consistent with expected trends in sorption due to the properties of the test vapor and the molecular structure of the passivating ligands in the sensor films. Classification algorithms including principal components analysis and Fisher’s linear discriminant were used to evaluate the discrimination performance of an array of such sensors. Each collection of sensors produced accurate classification of most vapors, with misclassification occurring primarily for vapors that had mutually similar polarity. The classification performance for an array that contained all of the sensor collections produced nearly perfect discrimination for all vapors studied. The dependence of the array size (i.e., the number of sensors) and the array chemical diversity on the discrimination performance indicated that, for an array of 20 sensors, an array size of 13 sensors or more produced the maximum discrimination performance

    Indonesian Muslim Women and the Gender Equality Movement

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    Throughout the history of Indonesia, the concepts of gender and power-relations between men and women have been linked to a shifting and fluctuating idea of what constitutes good women, good men, and good gender relationships within the context of Indonesia and Islam. To analyse these changing attitudes to women\u27s issues in Indonesia, we need to pay attention to several points: the character of the women\u27s organizations, whether fully independent, semi autonomous, or subsidiaries of existing male organizations; the important issues rising within the movements, as well as the strategies to deal with them; and lastly the influential factor of government intervention in the women\u27s movement. This paper tries to explore the Muslim women\u27s movement and its strategy to accommodate or resist from the domination of Islam in terms of the nation state, the constitution and the dominant cultural norms in Indonesia

    Response versus Chain Length of Alkanethiol-Capped Au Nanoparticle Chemiresistive Chemical Vapor Sensors

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    Au nanoparticles capped with a homologous series of straight chain alkanethiols (containing 4−11 carbons in length) have been investigated as chemiresistive organic vapor sensors. The series of alkanethiols was used to elucidate the mechanisms of vapor detection by such capped nanoparticle chemiresistive films and to highlight the molecular design principles that govern enhanced detection. The thiolated Au nanoparticle chemiresistors demonstrated rapid and reversible responses to a set of test vapors (n-hexane, n-heptane, n-octane, iso-octane, cyclohexane, toluene, ethyl acetate, methanol, ethanol, isopropanol, and 1-butanol) that possessed a variety of analyte physicochemical properties. The resistance sensitivity to nonpolar and aprotic polar vapors systematically increased as the chain length of the capping reagent increased. Decreases in the nanoparticle film resistances, which produced negative values of the differential resistance response, were observed upon exposure of the sensor films to alcohol vapors. The response signals became more negative with higher alcohol vapor concentrations, producing negative values of the sensor sensitivity. Sorption data measured on Au nanoparticle chemiresistor films using a quartz crystal microbalance allowed for the measurement of the partition coefficients of test vapors in the Au nanoparticle films. This measurement assumed that analyte sorption only occurred at the organic interface and not the surface of the Au core. Such an assumption produced partition coefficient values that were independent of the length of the ligand. Furthermore, the value of the partition coefficient was used to obtain the particle-to-particle interfacial effective dielectric constant of films upon exposure to analyte vapors. The values of the dielectric constant upon exposure to alcohol vapors suggested that the observed resistance response changes observed were not significantly influenced by this dielectric change, but rather were primarily influenced by morphological changes and by changes in the interparticle spacing

    Biofuels: A Hands-On Approach, Learning the Potential of Utilizing Non-Food Sources

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    The global energy economy is huge and thoughts of replacing large amounts of petroleum based fuels by massive levels of fermentation of grains are not realistic. On an energy basis what global agriculture produces for food will almost cover the energy demands if all of it is redirected to the production of fuels—either as alcohols for gasoline or as fat derivatives for diesel fuel. This means that chemical processes need to be developed that allow inclusion of non-food based agricultural and urban wastes as well as forest debris into the energy economy. These represent opportunities to capture new sources of energy that would otherwise not be captured. This project is based on the idea that every little bit helps, and focuses on a hands-on approach to isolating chemicals from fallen vegetation with an emphasis on adding to the transportation fuel pool. Hydrolysis of cellulosic wastes from various sources easily collected on our campus has been explored seeking ways to break them down to fermentable sugars. These sugars are then fermented to form alcohols suitable for inclusion in gasoline. Extraction of vegetable oils has also been explored. Finally an attempt has been made to quantify the impact such a strategy might have on global energy supplies if practiced on a wide-scale basis.https://scholar.dominican.edu/ug-student-posters/1001/thumbnail.jp

    International Students’ Perceptions of Service Quality in the UK Banking Sector: An Exploratory Study

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    This study reviews and evaluates international students’ perceptions of UK banks. The specific research objectives were to identify international students’ expectations and perceptions of service quality from UK banks and to assess the quality GAP or dissonance between these. A total of 297 international students studying in the UK responded to the survey. Data gathered was analyzed using Statistical Package for the Social Sciences (SPSS 16). The study reveals that the main areas of service quality with which international students are generally satisfied relates to tangibles such as physical layout and appearance. The key areas of dissatisfaction that the study identified were with factors related to reliability and empathy. This appears to be the first study in the UK banking sector that has focused on service quality with respect to international students

    Young Adults’ Susceptibility to Interpersonal Influence: A Case of Apparel Purchases

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    Purpose: This paper focuses on consumers’ susceptibility to interpersonal influence of young adults in the clothing apparels’ market in Malaysia. The researchers sought to clarify the relationship between interpersonal influences and young adults’ purchase decision, and the moderating impact of gender towards the relationship.   Design/methodology/approach: This study is exploratory in nature and adopts a quantitative approach. Primary data were obtained from young adults in Klang Valley (Malaysia) using mall intercept, by using 300 questionnaires were administrated using a multi-stage probability sampling technique to young adults between 19 to 30 years old.   Findings: Findings showed that value expressive, utilitarian, information, and brand consciousness influences were positively related to purchase decision. There are differences between genders toward the strength of interpersonal influence resulting in variation in their purchase decision.   Research limitations/implications: Different strategies should be designed to cater to both informational and brand consciousness influences between genders.   Originality/value: Marketers will be able to understand the importance of identifying the different susceptibility factors and gender attribute in their attempt to design different marketing strategies to attract customers.
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