Summary of investigations of engine response to distorted inlet conditions

A survey is presented of experimental and analytical experience of the NASA Lewis Research Center in engine response to inlet temperature and pressure distortions. This includes a description of the hardware and techniques employed, and a summary of the highlights of experimental investigations and analytical modeling. Distortion devices successfully simulated inlet distortion, and knowledge was gained about compression system response to different types of distortion. A list of NASA research references is included

A Unified Approach to Variational Derivatives of Modified Gravitational Actions

Our main aim in this paper is to promote the coframe variational method as a unified approach to derive field equations for any given gravitational action containing the algebraic functions of the scalars constructed from the Riemann curvature tensor and its contractions. We are able to derive a master equation which expresses the variational derivatives of the generalized gravitational actions in terms of the variational derivatives of its constituent curvature scalars. Using the Lagrange multiplier method relative to an orthonormal coframe, we investigate the variational procedures for modified gravitational Lagrangian densities in spacetime dimensions $n\geqslant 3$. We study well-known gravitational actions such as those involving the Gauss-Bonnet and Ricci-squared, Kretchmann scalar, Weyl-squared terms and their algebraic generalizations similar to generic $f(R)$ theories and the algebraic generalization of sixth order gravitational Lagrangians. We put forth a new model involving the gravitational Chern-Simons term and also give three dimensional New massive gravity equations in a new form in terms of the Cotton 2-form

Cosmological dynamics of exponential gravity

We present a detailed investigation of the cosmological dynamics based on $\exp (-R/{\Lambda})$ gravity. We apply the dynamical system approach to both the vacuum and matter cases and obtain exact solutions and their stability in the finite and asymptotic regimes. The results show that cosmic histories exist which admit a double de-Sitter phase which could be useful for describing the early and the late-time accelerating universe.Comment: 17 pages LaTeX, 3 figure

A new approach to cosmological perturbations in f(R) models

We propose an analytic procedure that allows to determine quantitatively the deviation in the behavior of cosmological perturbations between a given f(R) modified gravity model and a LCDM reference model. Our method allows to study structure formation in these models from the largest scales, of the order of the Hubble horizon, down to scales deeply inside the Hubble radius, without employing the so-called "quasi-static" approximation. Although we restrict our analysis here to linear perturbations, our technique is completely general and can be extended to any perturbative order.Comment: 21 pages, 2 figures; Revised version according to reviewer's suggestions; Typos corrected; Added Reference

An eHealth-Care Driven Perspective on 5G Networks and Infrastructure

This work describes the advancements that next generation mobile networks can bring to emergency services on the basis of a fully 5G enabled medical emergency response scenario. An ambulance service combining autonomous driving, advanced on-board patient monitoring, remote diagnosis and remote control from the hospital is introduced, allowing increased levels of care during patient transport and improved early diagnosis, thus enhancing patient survival rates. Furthermore, it is shown that such an ambulance service requires a variety of different traffic types that can only be supported concurrently and with guaranteed quality of service by a high-performance network fulfilling all 5G key performance indicators. The scenario described combines a multitude of aspects and applications enabled by 5G mobile communications, including autonomous driving, ultra-high definition video streaming, tactile remote interaction and continuous sensing, into a compelling showcase for a 5G enabled future. A centralized radio access 5G network with space division multiplexed optical fronthaul using analog radio-over-fiber and optical beamforming is analyzed, fully supporting SDN and NFV for advanced network slicing and quality of service guarantee.</p

Compactifying the state space for alternative theories of gravity

In this paper we address important issues surrounding the choice of variables when performing a dynamical systems analysis of alternative theories of gravity. We discuss the advantages and disadvantages of compactifying the state space, and illustrate this using two examples. We first show how to define a compact state space for the class of LRS Bianchi type I models in $R^n$-gravity and compare to a non--compact expansion--normalised approach. In the second example we consider the flat Friedmann matter subspace of the previous example, and compare the compact analysis to studies where non-compact non--expansion--normalised variables were used. In both examples we comment on the existence of bouncing or recollapsing orbits as well as the existence of static models.Comment: 18 pages, revised to match published versio

Isolation of Flow and Nonflow Correlations by Two- and Four-Particle Cumulant Measurements of Azimuthal Harmonics in sNN=\sqrt{s_{_{\rm NN}}} = 200 GeV Au+Au Collisions

A data-driven method was applied to measurements of Au+Au collisions at $\sqrt{s_{_{\rm NN}}} =$ 200 GeV made with the STAR detector at RHIC to isolate pseudorapidity distance $\Delta\eta$-dependent and $\Delta\eta$-independent correlations by using two- and four-particle azimuthal cumulant measurements. We identified a component of the correlation that is $\Delta\eta$-independent, which is likely dominated by anisotropic flow and flow fluctuations. It was also found to be independent of $\eta$ within the measured range of pseudorapidity $|\eta|<1$. The relative flow fluctuation was found to be $34\% \pm 2\% (stat.) \pm 3\% (sys.)$ for particles of transverse momentum $p_{T}$ less than $2$ GeV/$c$. The $\Delta\eta$-dependent part may be attributed to nonflow correlations, and is found to be $5\% \pm 2\% (sys.)$ relative to the flow of the measured second harmonic cumulant at $|\Delta\eta| > 0.7$

f(R) theories

Over the past decade, f(R) theories have been extensively studied as one of the simplest modifications to General Relativity. In this article we review various applications of f(R) theories to cosmology and gravity - such as inflation, dark energy, local gravity constraints, cosmological perturbations, and spherically symmetric solutions in weak and strong gravitational backgrounds. We present a number of ways to distinguish those theories from General Relativity observationally and experimentally. We also discuss the extension to other modified gravity theories such as Brans-Dicke theory and Gauss-Bonnet gravity, and address models that can satisfy both cosmological and local gravity constraints.Comment: 156 pages, 14 figures, Invited review article in Living Reviews in Relativity, Published version, Comments are welcom

In Situ Compatibilization of Biopolymer Ternary Blends by Reactive Extrusion with Low-Functionality Epoxy-Based Styrene Acrylic Oligomer

[EN] The present study reports on the use of low-functionality epoxy-based styrene¿acrylic oligomer (ESAO) to compatibilize immiscible ternary blends made of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), polylactide (PLA), and poly(butylene adipate-co-terephthalate) (PBAT). The addition during melt processing of low-functionality ESAO at two parts per hundred resin (phr) of biopolymer successfully changed the soften inclusion phase in the blend system to a thinner morphology, yielding biopolymer ternary blends with higher mechanical ductility and also improved oxygen barrier performance. The compatibilization achieved was ascribed to the in situ formation of a newly block terpolymer, i.e. PHBVb- PLA-b-PBAT, which was produced at the blend interface by the reaction of the multiple epoxy groups present in ESAO with the functional terminal groups of the biopolymers. This chemical reaction was mainly linear due to the inherently low functionality of ESAO and the more favorable reactivity of the epoxy groups with the carboxyl groups of the biopolymers, which avoided the formation of highly branched and/or cross-linked structures and thus facilitated the films processability. Therefore, the reactive blending of biopolymers at different mixing ratios with low-functionality ESAO represents a straightforward methodology to prepare sustainable plastics at industrial scale with different physical properties that can be of interest in, for instance, food packaging applications.This research was funded by the EU H2020 project YPACK (Reference number 773872) and by the Spanish Ministry of Science, Innovation, and Universities (MICIU) with project numbers MAT2017-84909-C2-2-R and AGL2015-63855-C2-1-R. L. Quiles-Carrillo wants to thank the Spanish Ministry of Education, Culture, and Sports (MECD) for financial support through his FPU Grant Number FPU15/03812. Torres-Giner also acknowledges the MICIU for his Juan de la Cierva contract (IJCI-2016-29675).Quiles-Carrillo, L.; Montanes, N.; Lagaron, J.; Balart, R.; Torres-Giner, S. (2019). In Situ Compatibilization of Biopolymer Ternary Blends by Reactive Extrusion with Low-Functionality Epoxy-Based Styrene Acrylic Oligomer. Journal of Polymers and the Environment. 27(1):84-96. https://doi.org/10.1007/s10924-018-1324-2S8496271Babu RP, O’Connor K, Seeram R (2013) Prog Biomater 2:8Torres-Giner S, Torres A, Ferrándiz M, Fombuena V, Balart R (2017) J Food Saf 37:e12348Quiles-Carrillo L, Montanes N, Boronat T, Balart R, Torres-Giner S (2017) Polym Test 61:421Zakharova E, Alla A, Martínez A, De Ilarduya S, Muñoz-Guerra (2015) RSC Adv 5:46395Steinbüchel A, Valentin HE (1995) FEMS Microbiol Lett 128:219McChalicher CWJ, Srienc F (2007) J Biotechnol 132:296Reis KC, Pereira J, Smith AC, Carvalho CWP, Wellner N, Yakimets I (2008) J Food Eng 89:361Vink ETH, Davies S (2015) Ind Biotechnol 11:167John RP, Nampoothiri KM, Pandey A (2006) Process Biochem 41:759Madhavan Nampoothiri K, Nair NR, John RP (2010) Biores Technol 101:8493Garlotta D (2001) J Polym Environ 9:63Lim LT, Auras R, Rubino M (2008) Prog Polym Sci 33:820Quiles-Carrillo L, Montanes N, Sammon C, Balart R, Torres-Giner S (2018) Ind Crops Prod 111:878Quiles-Carrillo L, Blanes-Martínez MM, Montanes N, Fenollar O, Torres-Giner S, Balart R (2018) Eur Polym J 98:402Witt U, Müller R-J, Deckwer W-D (1997) J Environ Polym Degrad 5:81Siegenthaler KO, Künkel A, Skupin G, Yamamoto M (2012) Ecoflex® and Ecovio®: biodegradable, performance-enabling plastics. In: Rieger B, Künkel A, Coates GW, Reichardt R, Dinjus E, Zevaco TA (eds) Synthetic biodegradable polymers. Springer, Berlin Heidelberg, p 91Jiang L, Wolcott MP, Zhang J (2006) Biomacromol 7:199Brandelero RPH, Yamashita F, Grossmann MVE (2010) Carbohyd Polym 82:1102Muthuraj R, Misra M, Mohanty AK (2014) J Polym Environ 22:336Porter RS, Wang L-H (1992) Polymer 33(10): 2019Koning C, Van Duin M, Pagnoulle C, Jerome R (1998) Prog Polym Sci 23:707Muthuraj R, Misra M, Mohanty AK (2017) J Appl Polym Sci 135:45726Ryan AJ (2002) Nat Mater 1:8Wu D, Zhang Y, Yuan L, Zhang M, Zhou W (2010) J Polym Sci Part B 48:756Kim CH, Cho KY, Choi EJ, Park JK (2000) J Appl Polym Sci 77:226Supthanyakul R, Kaabbuathong N, Chirachanchai S (2016) Polymer 105:1Na Y-H, He Y, Shuai X, Kikkawa Y, Doi Y, Inoue Y (2002) Biomacromolecules 3:1179Zeng J-B, Li K-A, Du A-K (2015) RSC Adv 5:32546Xanthos M, Dagli SS (1991) Polym Eng Sci 31:929Sundararaj U, Macosko CW (1995) Macromolecules 28:2647Milner ST, Xi H (1996) J Rheol 40:663Villalobos M, Awojulu A, Greeley T, Turco G, Deeter G (2006) Energy 31:3227Torres-Giner S, Montanes N, Boronat T, Quiles-Carrillo L, Balart R (2016) Eur Polym J 84:693Lehermeier HJ, Dorgan JR (2001) Polym Eng Sci 41:2172Liu B, Xu Q (2013) J Mater Sci Chem Eng 1:9Eslami H, Kamal MR (2013) J Appl Polym Sci 129:2418Loontjens T, Pauwels K, Derks F, Neilen M, Sham CK, Serné M (1997) J Appl Polym Sci 65:1813Ojijo V, Ray SS (2015) Polymer 80:1Frenz V, Scherzer D, Villalobos M, Awojulu AA, Edison M, Van Der Meer R (2008) Multifunctional polymers as chain extenders and compatibilizers for polycondensates and biopolymers. In: Technical papers, regional technical conference—society of plastics engineers, p. 3/1678Utracki LA (2002) Can J Chem Eng 80:1008Al-Itry R, Lamnawar K, Maazouz A (2012) Polym Degrad Stab 97:1898Lin S, Guo W, Chen C, Ma J, Wang B (2012) Mater Des (1980–2015) 36: 604Arruda LC, Magaton M, Bretas RES, Ueki MM (2015) Polym Test 43:27Wang Y, Fu C, Luo Y, Ruan C, Zhang Y, Fu Y (2010) J Wuhan Univ Technol Mater Sci Ed 25:774Wei D, Wang H, Xiao H, Zheng A, Yang Y (2015) Carbohyd Polym 123:275Abdelwahab MA, Taylor S, Misra M, Mohanty AK (2015) Macromol Mater Eng 300:299Sun Q, Mekonnen T, Misra M, Mohanty AK (2016) J Polym Environ 24:23Torres-Giner S, Gimeno-Alcañiz JV, Ocio MJ, Lagaron JM (2011) J Appl Polym Sci 122:914Miyata T, Masuko T (1998) Polymer 39:5515Muthuraj R, Misra M, Mohanty AK (2015) J Appl Polym Sci 132:42189Ren J, Fu H, Ren T, Yuan W (2009) Carbohyd Polym 77:576Torres-Giner S, Montanes N, Fenollar O, García-Sanoguera D, Balart R (2016) Mater Des 108:648Jamshidian M, Tehrany EA, Imran M, Jacquot M, Desobry S (2010) Compr Rev Food Sci Food Saf 9:552Savenkova L, Gercberga Z, Nikolaeva V, Dzene A, Bibers I, Kalnin M (2000) Process Biochem 35:573Costa ARM, Almeida TG, Silva SML, Carvalho LH, Canedo EL (2015) Polym Test 42:115Zhang K, Mohanty AK, Misra M (2012) ACS Appl Mater Interfaces 4:3091Zhang N, Wang Q, Ren J, Wang L (2009) J Mater Sci 44:250Chinsirikul W, Rojsatean J, Hararak B, Kerddonfag N, Aontee A, Jaieau K, Kumsang P, Sripethdee C (2015) Packag Technol Sci 28:741Auras R, Harte B, Selke S (2004) J Appl Polym Sci 92:1790Sanchez-Garcia MD, Gimenez E, Lagaron JM (2008) Carbohyd Polym 71:235Sanchez-Garcia MD, Gimenez E, Lagaron JM (2007) J Plast Film Sheeting 23:133Lagaron JM (2011) Multifunctional and nanoreinforced polymers for food packaging. In: Multifunctional and nanoreinforced polymers for food packaging. Woodhead Publishing, Cambridge, p 

Nucleation and crystallization in bio-based immiscible polyester blends

Bio-based thermoplastic polyesters are highly promising materials as they combine interesting thermal and physical properties and in many cases biodegradability. However, sometimes the best property balance can only be achieved by blending in order to improve barrier properties, biodegradability or mechanical properties. Nucleation, crystallization and morphology are key factors that can dominate all these properties in crystallizable biobased polyesters. Therefore, their understanding, prediction and tailoring is essential. In this work, after a brief introduction about immiscible polymer blends, we summarize the crystallization behavior of the most important bio-based (and immiscible) polyester blends, considering examples of double-crystalline components. Even though in some specific blends (e.g., polylactide/polycaprolactone) many efforts have been made to understand the influence of blending on the nucleation, crystallization and morphology of the parent components, there are still many points that have yet to be understood. In the case of other immiscible polyester blends systems, the literature is scarce, opening up opportunities in this environmentally important research topic.The authors would like to acknowledge funding by the BIODEST project ((RISE) H2020-MSCA-RISE-2017-778092