Enzymatic hydrolysis of waste fats, oils and greases (FOGs) : Status, prospective, and process intensification alternatives

The increasing global generation of waste fats, oils, and greases (FOGs) is resulting in a cascade of economic, environmental, and public health issues as mismanagement is a common practice worldwide. Hence industrial exploitation and valorization is required towards a circular economy within the oleochemical industry. FOGs suitable for further oleochemical exploitation include used cooking oils, trap greases, mill effluents, rendering fats, spent earths from filtration and bleaching, deodorization distillates, soapstocks, and sewage sludges, among others. However main challenge for FOGs harnessing are their heterogeneity and the high content of impurities, acidity, and water. Alternatively, waste FOGs could be subjected to complete hydrolysis to recover free fatty acids (FFAs), which are widely used oleochemical feedstocks. Different catalysts have been explored for this process, however, lipases are of particular interest because they are able to work on low-quality feedstocks under milder operating conditions. This paper reviews most recent investigations on the enzymatic hydrolysis of waste FOGs, describing main processes characteristics, operating conditions, challenges, current attempts to improve enzymes performance, the use of combined chemical processes to improve feedstock utilization, and the implementation of intensified processing technologies. Potential for industrial implementation and future research possibilities in the process intensification field are identified

Life Cycle Analysis for the Recycled Expanded Polystyrene (EPS) and Polypropylene (PP) Mixture as an Alternative to the Material in the Construction Sector

The continuous generation and accumulation of solid waste is a critical problem at the world level and require urgent action. Therefore, the present paper contains an alternative of using two solid plastic wastes, determining the use of polymeric synthesis made from recycled polypropylene (PP) and expanded polystyrene (EPS). First, the research developed a new material using these two recycled raw materials and evaluated its physical-mechanical properties. The next step was the comparison of the properties with different potentially replaceable materials. Finally, polyvinyl chloride (PVC) was the material identified as possible to be replaced by the mixture (EPS+PP) because of the similar values of its properties, with specific use for coating electrical installations and internal communications. The study uses the Life Cycle Assessment methodology (LCA) to evaluate the material's environmental performance. This paper reports the inventory data of the new material process validated in a plastic plant in Bogotá (Colombia). Consequently, by using the mass and energy balances, the authors evaluate the environmental indicators for the process proposed and then compare the results with the ones of PVC in the Ecoinvent databases. The study used a "cradle to door" approach and SIMAPRO software in this step. The LCA results show that the new material generates less environmental impact than conventional (PVC). Furthermore, the present research results allow new possibilities for incorporating circular economy models in the construction sector. As a result, the new material produces a lower environmental impact than PVC

Exciting Modes due to the Aberration of Gravitational Waves: Measurability for Extreme-Mass-Ratio Inspirals

Gravitational waves from a source moving relative to us can suffer from special-relativistic effects such as aberration. The required velocities for these to be significant are on the order of 1000  km s⁻¹. This value corresponds to the velocity dispersion that one finds in clusters of galaxies. Hence, we expect a large number of gravitational-wave sources to have such effects imprinted in their signals. In particular, the signal from a moving source will have its higher modes excited, i.e., (3,3) and beyond. We derive expressions describing this effect and study its measurability for the specific case of a circular, nonspinning extreme-mass-ratio inspiral. We find that the excitation of higher modes by a peculiar velocity of 1000  km s⁻¹ is detectable for such inspirals with signal-to-noise ratios of ≳20. Using a Fisher matrix analysis, we show that the velocity of the source can be measured to a precision of just a few percent for a signal-to-noise ratio of 100. If the motion of the source is ignored, parameter estimates could be biased, e.g., the estimated masses of the components through a Doppler shift. Conversely, by including this effect in waveform models, we could measure the velocity dispersion of clusters of galaxies at distances inaccessible to light

Nuclear matter effects on J/ψJ/\psi production in asymmetric Cu+Au collisions at sNN\sqrt{s_{_{NN}}} = 200 GeV

We report on $J/\psi$ production from asymmetric Cu+Au heavy-ion collisions at $\sqrt{s_{_{NN}}}$=200 GeV at the Relativistic Heavy Ion Collider at both forward (Cu-going direction) and backward (Au-going direction) rapidities. The nuclear modification of $J/\psi$ yields in Cu$+$Au collisions in the Au-going direction is found to be comparable to that in Au$+$Au collisions when plotted as a function of the number of participating nucleons. In the Cu-going direction, $J/\psi$ production shows a stronger suppression. This difference is comparable in magnitude and has the same sign as the difference expected from shadowing effects due to stronger low-$x$ gluon suppression in the larger Au nucleus. The relative suppression is opposite to that expected from hot nuclear matter dissociation, since a higher energy density is expected in the Au-going direction.Comment: 349 authors, 10 pages, 4 figures, and 4 tables. Submitted to Phys. Rev. C. For v2, fixed LaTeX error in 3rd-to-last sentence. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Centrality categorization for R_{p(d)+A} in high-energy collisions

High-energy proton- and deuteron-nucleus collisions provide an excellent tool for studying a wide array of physics effects, including modifications of parton distribution functions in nuclei, gluon saturation, and color neutralization and hadronization in a nuclear environment, among others. All of these effects are expected to have a significant dependence on the size of the nuclear target and the impact parameter of the collision, also known as the collision centrality. In this article, we detail a method for determining centrality classes in p(d)+A collisions via cuts on the multiplicity at backward rapidity (i.e., the nucleus-going direction) and for determining systematic uncertainties in this procedure. For d+Au collisions at sqrt(s_NN) = 200 GeV we find that the connection to geometry is confirmed by measuring the fraction of events in which a neutron from the deuteron does not interact with the nucleus. As an application, we consider the nuclear modification factors R_{p(d)+A}, for which there is a potential bias in the measured centrality dependent yields due to auto-correlations between the process of interest and the backward rapidity multiplicity. We determine the bias correction factor within this framework. This method is further tested using the HIJING Monte Carlo generator. We find that for d+Au collisions at sqrt(s_NN)=200 GeV, these bias corrections are small and vary by less than 5% (10%) up to p_T = 10 (20) GeV. In contrast, for p+Pb collisions at sqrt(s_NN) = 5.02 TeV we find these bias factors are an order of magnitude larger and strongly p_T dependent, likely due to the larger effect of multi-parton interactions.Comment: 375 authors, 18 pages, 16 figures, 4 tables. Submitted to Phys. Rev. C. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

L\'evy-stable two-pion Bose-Einstein correlations in sNN=200\sqrt{s_{_{NN}}}=200 GeV Au++Au collisions

We present a detailed measurement of charged two-pion correlation functions in 0%-30% centrality $\sqrt{s_{_{NN}}}=200$ GeV Au$+$Au collisions by the PHENIX experiment at the Relativistic Heavy Ion Collider. The data are well described by Bose-Einstein correlation functions stemming from L\'evy-stable source distributions. Using a fine transverse momentum binning, we extract the correlation strength parameter $\lambda$, the L\'evy index of stability $\alpha$ and the L\'evy length scale parameter $R$ as a function of average transverse mass of the pair $m_T$. We find that the positively and the negatively charged pion pairs yield consistent results, and their correlation functions are represented, within uncertainties, by the same L\'evy-stable source functions. The $\lambda(m_T)$ measurements indicate a decrease of the strength of the correlations at low $m_T$. The L\'evy length scale parameter $R(m_T)$ decreases with increasing $m_T$, following a hydrodynamically predicted type of scaling behavior. The values of the L\'evy index of stability $\alpha$ are found to be significantly lower than the Gaussian case of $\alpha=2$, but also significantly larger than the conjectured value that may characterize the critical point of a second-order quark-hadron phase transition.Comment: 448 authors, 25 pages, 11 figures, 4 tables, 2010 data. v2 is version accepted for publication in Phys. Rev. C. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Cross Section and Transverse Single-Spin Asymmetry of η\eta Mesons in p↑+pp^{\uparrow}+p Collisions at s=200\sqrt{s}=200 GeV at Forward Rapidity

We present a measurement of the cross section and transverse single-spin asymmetry ($A_N$) for $\eta$ mesons at large pseudorapidity from $\sqrt{s}=200$~GeV $p^{\uparrow}+p$ collisions. The measured cross section for $0.5<p_T<5.0$~GeV/$c$ and $3.0<|\eta|<3.8$ is well described by a next-to-leading-order perturbative-quantum-chromodynamics calculation. The asymmetries $A_N$ have been measured as a function of Feynman-$x$ ($x_F$) from $0.2<|x_{F}|<0.7$, as well as transverse momentum ($p_T$) from $1.0<p_T<4.5$~GeV/$c$. The asymmetry averaged over positive $x_F$ is $\langle{A_{N}}\rangle=0.061{\pm}0.014$. The results are consistent with prior transverse single-spin measurements of forward $\eta$ and $\pi^{0}$ mesons at various energies in overlapping $x_F$ ranges. Comparison of different particle species can help to determine the origin of the large observed asymmetries in $p^{\uparrow}+p$ collisions.Comment: 484 authors, 13 pages, 11 figures, 4 tables, 2008 data. v2 is version accepted by Phys. Rev. D. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be)publicly available at http://www.phenix.bnl.gov/papers.htm