9,080 research outputs found
Systematic Selection of Green Solvents and Process Optimization for the Hydroformylation of Long-Chain Olefines
Including ecologic and environmental aspects in chemical engineering requires new methods for process design and optimization. In this work, a hydroformylation process of long-chain olefines is investigated. A thermomorphic multiphase system is employed that is homogeneous at reaction conditions and biphasic at lower temperatures for catalyst recycling. In an attempt to replace the toxic polar solvent N,N-dimethylformamide (DMF), ecologically benign alternatives are selected using a screening approach. Economic process optimization is conducted for DMF and two candidate solvents. It is found that one of the green candidates performs similarly well as the standard benchmark solvent DMF, without being toxic. Therefore, the candidate has the potential to replace it
Surrogate Modeling for Liquid–Liquid Equilibria Using a Parameterization of the Binodal Curve
A photon transport problem with a time-dependent point source
We consider a time-dependent problem of photon transport in an interstellar cloud with a point photon source modeled by a Dirac δ functional. The existence of a unique distributional solution to this problem is established by using the theory of continuous semigroups of operators on locally convex spaces coupled with a constructive approach for producing spaces of generalized functions
Constructing applicative functors
Applicative functors define an interface to computation that is more general, and correspondingly weaker, than that of monads. First used in parser libraries, they are now seeing a wide range of applications. This paper sets out to explore the space of non-monadic applicative functors useful in programming. We work with a generalization, lax monoidal functors, and consider several methods of constructing useful functors of this type, just as transformers are used to construct computational monads. For example, coends, familiar to functional programmers as existential types, yield a range of useful applicative functors, including left Kan extensions. Other constructions are final fixed points, a limited sum construction, and a generalization of the semi-direct product of monoids. Implementations in Haskell are included where possible
Development and validation of measures to evaluate adolescents' knowledge about human papillomavirus (HPV), involvement in HPV vaccine decision-making, self-efficacy to receive the vaccine and fear and anxiety
Objectives: We describe the development and validation of measures of human papillomavirus (HPV)/HPV vaccination knowledge, fear/anxiety about vaccination, involvement in HPV vaccine decision-making, and self-efficacy with regard to getting the vaccine, designed to evaluate the efficacy of an intervention to affect these domains (collectively termed the HAVIQ: HPV Adolescent Vaccine Intervention Questionnaire). / Study design: Literature search, cognitive interviews and cross-sectional survey. / Methods: A literature search identified existing items that were modified for the present measures. Experts reviewed draft measures for face and content validity. Cognitive interviews with adolescents were also used to assess content validity. Adolescents completed the measures and an internal reliability analysis of each measure was performed. / Results: The four experts concurred that the measures had face validity. Cognitive interviews identified items requiring refinement. Content validity was examined with ten experts and was deemed acceptable. There were 1800 adolescents who completed the measures; Cronbach's alpha was >0.6 for three of the four measures. The four final measures are brief, comprising 25 items in total. / Conclusions: The measures are robustly developed and validity-tested. The HAVIQ may be used in research settings to evaluate adolescents' knowledge and experiences of the process of HPV vaccination in a school-based vaccination programme
Tests of redshift-space distortions models in configuration space for the analysis of the BOSS final data release
Citation: White, M., Reid, B., Chuang, C. H., Tinker, J. L., McBride, C. K., Prada, F., & Samushia, L. (2015). Tests of redshift-space distortions models in configuration space for the analysis of the BOSS final data release. Monthly Notices of the Royal Astronomical Society, 447(1), 234-245. doi:10.1093/mnras/stu2460Observations of redshift-space distortions in spectroscopic galaxy surveys offer an attractive method for observing the build-up of cosmological structure, which depends both on the expansion rate of the Universe and our theory of gravity. In preparation for analysis of redshift-space distortions from the Baryon Oscillation Spectroscopic Survey (BOSS) final data release, we compare a number of analytic and phenomenological models, specified in configuration space, to mock catalogues derived in different ways from several N-body simulations. The galaxies in each mock catalogue have properties similar to those of the higher redshift galaxies measured by BOSS but differ in the details of how small-scale velocities and halo occupancy are determined. We find that all of the analytic models fit the simulations over a limited range of scales while failing at small scales. We discuss which models are most robust and on which scales they return reliable estimates of the rate of growth of structure: we find that models based on some form of resummation can fit our N-body data for BOSS-like galaxies above 30 h(-1) Mpc well enough to return unbiased parameter estimates
Synthetic Galaxy Images and Spectra from the Illustris Simulation
We present our methods for generating a catalog of 7,000 synthetic images and
40,000 integrated spectra of redshift z = 0 galaxies from the Illustris
Simulation. The mock data products are produced by using stellar population
synthesis models to assign spectral energy distributions (SED) to each star
particle in the galaxies. The resulting synthetic images and integrated SEDs
therefore properly reflect the spatial distribution, stellar metallicity
distribution, and star formation history of the galaxies. From the synthetic
data products it is possible to produce monochromatic or color-composite
images, perform SED fitting, classify morphology, determine galaxy structural
properties, and evaluate the impacts of galaxy viewing angle. The main
contribution of this paper is to describe the production, format, and
composition of the image catalog that makes up the Illustris Simulation
Obsevatory. As a demonstration of this resource, we derive galactic stellar
mass estimates by applying the SED fitting code FAST to the synthetic galaxy
products, and compare the derived stellar masses against the true stellar
masses from the simulation. We find from this idealized experiment that
systematic biases exist in the photometrically derived stellar mass values that
can be reduced by using a fixed metallicity in conjunction with a minimum
galaxy age restriction.Comment: 21 pages, 17 figures, submitted to MNRAS. Comments welcom
- …