In the present paper, the performance and emission characteristics of a conventional four cylinder spark ignition (SI) engine operated on hydrogen and gasoline are investigated experimentally. The ...compressed hydrogen at 20
MPa has been introduced to the engine adopted to operate on gaseous hydrogen by external mixing. Two regulators have been used to drop the pressure first to 300
kPa, then to atmospheric pressure. The variations of torque, power, brake thermal efficiency, brake mean effective pressure, exhaust gas temperature, and emissions of
NO
x
, CO,
CO
2
, HC, and
O
2
versus engine speed are compared for a carbureted SI engine operating on gasoline and hydrogen. Energy analysis also has studied for comparison purpose. The test results have been demonstrated that power loss occurs at low speed hydrogen operation whereas high speed characteristics compete well with gasoline operation. Fast burning characteristics of hydrogen have permitted high speed engine operation. Less heat loss has occurred for hydrogen than gasoline.
NO
x
emission of hydrogen fuelled engine is about 10 times lower than gasoline fuelled engine. Finally, both first and second law efficiencies have improved with hydrogen fuelled engine compared to gasoline engine. It has been proved that hydrogen is a very good candidate as an engine fuel. The obtained data are also very useful for operational changes needed to optimize the hydrogen fueled SI engine design.
Electropolishing is a common method for decreasing surface roughness and removing surface irregularities. In this paper the electropolishing of nickel and cobalt are successfully demonstrated in a ...deep eutectic solvent, comprising a 2:1 molar mixture of ethylene glycol and choline chloride. Voltammetric and electrochemical impedance studies were used to characterise the polishing mechanism and show that film formation occurs prior to polishing. Scanning electron microscopy and atomic force microscopy were used to characterise the morphology before and after polishing and 3D optical microscopy was used in-situ to observe film formation during polishing. This study shows that the impact of film formation and subsequently mass transport are responsible for electropolishing of both metals in the choline chloride-based ionic liquid.
Quality of Decision Making and Group Norms Postmes, Tom; Spears, Russell; Cihangir, Sezgin
Journal of personality and social psychology,
06/2001, Letnik:
80, Številka:
6
Journal Article
Recenzirano
Two studies investigated the impact of group norms for maintaining consensus versus norms for critical thought on group decisions in a modification of the biased sampling paradigm (
G. Stasser & W. ...Titus, 1985
). Both studies showed that critical norms improved the quality of decisions, whereas consensus norms did not. This effect appeared to be mediated by the perceived value of shared and unshared information: Consensus norm groups valued shared information more highly than critical groups did, and valence was a good predictor of decision outcome. In addition, the 2nd study showed that the group norm manipulation has no impact on individual decisions, consistent with the assumption that this is a group effect. Results suggest that the content of group norms is an important factor influencing the quality of group decision-making processes and that the content of group norms may be related to the group's proneness for groupthink.
Abstract Zinc (Zn)-based biodegradable alloys have been at the forefront of absorbable biomaterial research in recent years due to their high biocompatibility and corrosion rates. The arc melting ...process was used to produce the Zn–1Cu–1Ag biodegradable alloy. The influence of different plastic deformation rates on the microstructure of the material was examined after the cold rolling at deformation rates of 47% and 61%. The undeformed and deformed alloys have been hydroxyapatite-coated using the electrophoretic deposition process to improve its surface, corrosion, and bioactivity properties. Optical, XRD, SEM, and EDS examinations were used to analyze the samples’ uncoated, coated, and rolled-unrolled forms. The nucleation of the (Ag, Cu)Zn4 secondary phase was formed during the rolling process. Hardness and compression tests were used to determine the mechanical properties of cast and rolled alloys, and in vitro corrosion tests were carried out in simulated body fluid. Antimicrobial and cell viability tests are executed to demonstrate the biocompatibility of the deformed and HA-coated Zn–1Cu–1Ag alloy. The mechanical properties were improved after the rolling process, with the highest results found in 47% of the rolled samples exhibiting a compressive strength of 412.65 ± 0.5 MPa and 61% of the rolled samples exhibiting a hardness value of 88.1 ± 0.5 HV. The samples that were rolled (61%) and coated with hydroxyapatite (HA) exhibited the highest level of corrosion resistance. The antimicrobial tests revealed that the rolled and HA coated Zn1Cu1Ag groups exhibited greater inhibition rates (47 and 61%) compared to the other groups when tested against E. coli. The HA-coated groups exhibited good cell viability ratios, with the maximum viability seen in the rolled and HA-coated group at 47%. Graphical Abstract
Patient satisfaction surveys are increasingly used for benchmarking purposes. In the Netherlands, the results of these surveys are reported at the univariate level without taking case mix factors ...into account. The first objective of the present study was to determine whether differences in patient satisfaction are attributed to the hospital, department or patient characteristics. Our second aim was to investigate which case mix variables could be taken into account when satisfaction surveys are carried out for benchmarking purposes. Patients who either were discharged from eight academic and fourteen general Dutch hospitals or visited the outpatient departments of the same hospitals in 2005 participated in cross-sectional satisfaction surveys. Satisfaction was measured on six dimensions of care and one general dimension. We used multilevel analysis to estimate the proportion of variance in satisfaction scores determined by the hospital and department levels by calculating intra-class correlation coefficients (ICCs). Hospital size, hospital type, population density and response rate are four case mix variables we investigated at the hospital level. We also measured the effects of patient characteristics (gender, age, education, health status, and mother language) on satisfaction. We found ICCs on hospital and department levels ranging from 0% to 4% for all dimensions. This means that only a minor part of the variance in patient satisfaction scores is attributed to the hospital and department levels. Although all patient characteristics had some statistically significant influence on patient satisfaction, age, health status and education appeared to be the most important determinants of patient satisfaction and could be considered for case mix correction. Gender, mother language, hospital type, hospital size, population density and response rate seemed to be less important determinants. The explained variance of the patient and hospital characteristics ranged from 3% to 5% for the different dimensions. Our conclusions are, first, that a substantial part of the variance is on the patient level, while only a minor part of the variance is at the hospital and department levels. Second, patient satisfaction outcomes in the Netherlands can be corrected by the case mix variables age, health status and education.
Quality of Decision Making and Group Norms Postmes, Tom; Spears, Russell; Cihangir, Sezgin
Journal of personality and social psychology,
06/2001, Letnik:
80, Številka:
6
Journal Article
Recenzirano
Two studies investigated the impact of group norms for maintaining consensus versus norms for critical thought on group decisions in a modification of the biased sampling paradigm (G. Stasser & W. ...Titus, 1985). Both studies showed that critical norms improved the quality of decisions, whereas consensus norms did not. This effect appeared to be mediated by the perceived value of shared & unshared information. Consensus norm groups valued shared information more highly than critical groups did, & valence was a good predictor of decision outcome. In addition, the 2nd study showed that the group norm manipulation has no impact on individual decisions, consistent with the assumption that this is a group effect. Results suggest that the content of group norms is an important factor influencing the quality of group decision-making processes & that the content of group norms may be related to the group's proneness for groupthink. 2 Tables, 3 Figures, 53 References. Copyright 2001 The American Psychological Association.
The W boson helicity fractions from top quark decays in tt‾ events are measured using data from proton–proton collisions at a centre-of-mass energy of 8TeV. The data were collected in 2012 with the ...CMS detector at the LHC, corresponding to an integrated luminosity of 19.8fb−1. Events are reconstructed with either one muon or one electron, along with four jets in the final state, with two of the jets being identified as originating from b quarks. The measured helicity fractions from both channels are combined, yielding F0=0.681±0.012(stat)±0.023(syst), FL=0.323±0.008(stat)±0.014(syst), and FR=−0.004±0.005(stat)±0.014(syst) for the longitudinal, left-, and right-handed components of the helicity, respectively. These measurements of the W boson helicity fractions are the most accurate to date and they agree with the predictions from the standard model.
The differential cross sections for inclusive production of B+ hadrons are measured as a function of the B+ transverse momentum pTB and rapidity yB in pp collisions at a centre-of-mass energy of 13 ...TeV, using data collected by the CMS experiment that correspond to an integrated luminosity of 48.1 pb−1. The measurement uses the exclusive decay channel B+→J/ψK+, with J/ψ mesons that decay to a pair of muons. The results show a reasonable agreement with theoretical calculations within the uncertainties.
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