198 research outputs found
Boiler for generating high quality vapor
Boiler supplies vapor for use in turbines by imparting a high angular velocity to the liquid annulus in heated rotating drum. Drum boiler provides a sharp interface between boiling liquid and vapor, thereby, inhibiting the formation of unwanted liquid droplets
Gravitational Collapse of a Homogeneous Scalar Field in Deformed Phase Space
We study the gravitational collapse of a homogeneous scalar field, minimally
coupled to gravity, in the presence of a particular type of dynamical
deformation between the canonical momenta of the scale factor and of the scalar
field. In the absence of such a deformation, a class of solutions can be found
in the literature [R. Goswami and P. S. Joshi, arXiv:gr-qc/0410144],
%\cite{JG04}, whereby a curvature singularity occurs at the collapse end state,
which can be either hidden behind a horizon or be visible to external
observers. However, when the phase-space is deformed, as implemented herein
this paper, we find that the singularity may be either removed or instead,
attained faster. More precisely, for negative values of the deformation
parameter, we identify the emergence of a negative pressure term, which slows
down the collapse so that the singularity is replaced with a bounce. In this
respect, the formation of a dynamical horizon can be avoided depending on the
suitable choice of the boundary surface of the star. Whereas for positive
values, the pressure that originates from the deformation effects assists the
collapse toward the singularity formation. In this case, since the collapse
speed is unbounded, the condition on the horizon formation is always satisfied
and furthermore the dynamical horizon develops earlier than when the
phase-space deformations are absent. These results are obtained by means of a
thoroughly numerical discussion.Comment: 17 pages, 17 figure
Loop quantum effect and the fate of tachyon field collapse
We study the fate of gravitational collapse of a tachyon field matter. In
presence of an inverse square potential a black hole forms. Loop quantum
corrections lead to the avoidance of classical singularities, which is followed
by an outward flux of energy.Comment: Contribution to the conference of Loops'11, Madri
Energy Efficiency Measures for an Electrical Material Industry
The main goal of the present paper is to present the study of energy efficiency measures for an electrical material industry. The high-energy consumption of this kind of industry lead companies to search for solutions that allow increasing the energy efficiency in their installations and in the processes, promoting the reduction of the energy consumption and costs. In this context, the objectives of this study emerged, which resulted from the main needs identified by the company. Therefore, the work was divided into four parts. The first one, was the study of replacing the existing lighting (mainly mercury vapor lamps by led); another study conducted was the replacement of the electric motors in injection machines by new and more efficient ones; the third one was the installation of a photovoltaic solar system (for self-consumption) and, finally, the project of a new power converter station for the company. The energy efficiency studies carried out are based on: a careful analysis of the data provided by the company; all the measurements done; the consumption profiles that have been drawn; an extensive market research (with the purpose of finding the most efficient solutions for each case); and in already existing and proven calculation methodologies, leading, in this way, to a greater reliability of the obtained results. These studies showed to which extent the implementation of the various measures presented are economically viable, their impact on the reduction of energy consumption and the annual savings achieved.This work was supported by Coimbra Institute of Engineering – Polytechnic Institute of Coimbra and by projects: UID/MULTI/00308/2019 (supported by the Portuguese ‘Fundação para a Ciência e a Tecnologia’: FCT – Foundation for Science and Technology) and by the European Regional Development Fund through the COMPETE 2020 Programme, FCT Portuguese Foundation for Science and Technology within project T4ENERTEC (POCI-01- 0145-FEDER-029820)
Inflationary Universe in Deformed Phase Space Scenario
We consider a noncommutative (NC) inflationary model with a homogeneous
scalar field minimally coupled to gravity. The particular NC inflationary
setting produces entirely new consequences. We first analyze the free field
case and subsequently examine the situation where the scalar field is subjected
to a polynomial and exponential potentials. We propose to use a canonical
deformation between momenta, in a spatially flat FLRW universe, and while the
Friedmann equation remains unaffected the Friedmann acceleration equation (and
thus the Klein-Gordon equation) is modified by an extra term linear in the NC
parameter. This concrete noncommutativity on the momenta allows interesting
dynamics that other NC models seem not to allow. Let us be more precise. This
extra term behaves as the sole explicit pressure that under the right
circumstances implies a period of accelerated expansion of the universe. We
find that in the absence of the scalar field potential, and in contrast with
the commutative case, in which the scale factor always decelerates, we obtain
an inflationary phase for small negative values of the NC parameter.
Subsequently, the period of accelerated expansion is smoothly replaced by an
appropriate deceleration phase providing an interesting model regarding the
graceful exit problem in inflationary models.
Moreover, in the case of the free scalar field, we show that not only the
horizon problem is solved but also there is some resemblance between the
evolution equation of the scale factor associated to our model and that for the
(Starobinsky) inflationary model. Therefore, our herein NC model not only
can be taken as an appropriate scenario to get a successful kinetic inflation,
but also is a convenient setting to obtain inflationary universe possessing the
graceful exit when scalar field potentials are present.Comment: 15 pages, 9 figures, Accepted to publish in Annals of Physic
Dilaton Quantum Cosmology with a Schrodinger-like equation
A quantum cosmological model with radiation and a dilaton scalar field is
analysed. The Wheeler-deWitt equation in the mini-superspace induces a
Schr\"odinger equation, which can be solved. An explicit wavepacket is
constructed for a particular choice of the ordering factor. A consistent
solution is possible only when the scalar field is a phantom field. Moreover,
although the wavepacket is time dependent, a Bohmian analysis allows to extract
a bouncing behaviour for the scale factor.Comment: 14 pages, 3 figures in eps format. Minors corrections, new figure
New Peptide Functionalized Nanostructured Lipid Carriers with CNS Drugs and Evaluation Anti-proliferative Activity
Nanoparticulate systems have been widely investigated as delivery vectors for efficient drug delivery in different diseases. Nanostructured lipid carriers (NLC) are composed of both solid and liquid lipids (glyceryl dibehenate and diethylene glycol monoethyl ether) and have demonstrated enhanced biological compatibility and increased drug loading capability. Furthermore, the use of peptides, in particular cell-penetrating peptides, to functionalize nanoparticles and enhance cell membrane permeation was explored in this paper. In this paper, we described the synthesis of a new conjugated of tranylcypromine with MAP. In addition, taking into consideration our previous results, this study developed different NLCs loaded with three central nervous system (CNS) drugs (tacrine (TAC), rasagiline (RAS), and tranylcypromine (TCP)) functionalized with model amphipathic peptide (MAP) and evaluated their activity against cancer cells. Particle size analysis demonstrated NLC presented less than 200 nm and a polydispersity index less than 0.3. Moreover, in vitro results showed that conjugation of MAP with drugs led to a higher decrease in cell viability of a neuroblastoma cell line and Caco-2 cell line, more than MAP alone. Furthermore, NLC encapsulation contributed to higher cellular delivery and enhanced toxic activity at lower concentrations when compared with free or co-administration drug-MAP conjugate.Funding: This work was financed by FEDER—Fundo Europeu de Desenvolimento Regional through the COMPETE 2020—Operational Programme for Competitiveness and Internationalization (POCI), Portugal 2020, and by Portuguese funds through FCT—Fundação para a Ciência e a Tecnologia, in a framework of the projects in CINTESIS, R&D Unit (reference UIDB/4255/2020, RISE (RISELA/P/0053/2020) and iMed.ULisboa (UID/DTP/04138/2019), as well by LA/P/0045/2020 (ALiCE), UIDB/50020/2020 and UIDP/50020/2020 (LSRE-LCM), funded by national funds through FCT/MCTES (PIDDAC). N.V. also thanks support from FCT and FEDER (European Union), award number IF/00092/2014/CP1255/CT0004 and CHAIR in Onco-Innovation.
Acknowledgments: N.V. thanks support FCT and FEDER (European Union), award number IF/00092/ 2014/CP1255/CT0004 and CHAIR in Onco-Innovation. S.S. thanks FCT for PhD Grant (PD/BD/135456/ 2017) and PhD Programme in Medicines and Pharmaceutical Innovation (i3DU) from the University of Lisbon (Portugal) and the University of Porto (Portugal). D.D. acknowledges FCT for funding her PhD grant (SFRH/BD/140734/2018).info:eu-repo/semantics/publishedVersio
Design and Characterization of an Ethosomal Gel Encapsulating Rosehip Extract
: Rising environmental awareness drives green consumers to purchase sustainable cosmetics based on natural bioactive compounds. The aim of this study was to deliver Rosa canina L. extract as a botanical ingredient in an anti-aging gel using an eco-friendly approach. Rosehip extract was first characterized in terms of its antioxidant activity through a DPPH assay and ROS reduction test and then encapsulated in ethosomal vesicles with different percentages of ethanol. All formulations were characterized in terms of size, polydispersity, zeta potential, and entrapment efficiency. Release and skin penetration/permeation data were obtained through in vitro studies, and cell viability was assessed using an MTT assay on WS1 fibroblasts. Finally, ethosomes were incorporated in hyaluronic gels (1% or 2% w/v) to facilitate skin application, and rheological properties were studied. Rosehip extract (1 mg/mL) revealed a high antioxidant activity and was successfully encapsulated in ethosomes containing 30% ethanol, having small sizes (225.4 ± 7.0 nm), low polydispersity (0.26 ± 0.02), and good entrapment efficiency (93.41 ± 5.30%). This formulation incorporated in a hyaluronic gel 1% w/v showed an optimal pH for skin application (5.6 ± 0.2), good spreadability, and stability over 60 days at 4 °C. Considering sustainable ingredients and eco-friendly manufacturing technology, the ethosomal gel of rosehip extract could be an innovative and green anti-aging skincare product
The mTOR-Regulated Phosphoproteome Reveals a Mechanism of mTORC1-Mediated Inhibition of Growth Factor Signaling
September 21 Author ManuscriptThe mammalian target of rapamycin (mTOR) protein kinase is a master growth promoter that nucleates two complexes, mTORC1 and mTORC2. Despite the diverse processes controlled by mTOR, few substrates are known. We defined the mTOR-regulated phosphoproteome by quantitative mass spectrometry and characterized the primary sequence motif specificity of mTOR using positional scanning peptide libraries. We found that the phosphorylation response to insulin is largely mTOR dependent and that mTOR exhibits a unique preference for proline, hydrophobic, and aromatic residues at the +1 position. The adaptor protein Grb10 was identified as an mTORC1 substrate that mediates the inhibition of phosphoinositide 3-kinase typical of cells lacking tuberous sclerosis complex 2 (TSC2), a tumor suppressor and negative regulator of mTORC1. Our work clarifies how mTORC1 inhibits growth factor signaling and opens new areas of investigation in mTOR biology.National Institutes of Health (U.S.) (Grant CA103866)National Institutes of Health (U.S.) (Grant AI47389)United States. Department of Defense (W81XWH-07-0448)W. M. Keck FoundationLAM FoundationAmerican Cancer SocietyHoward Hughes Medical Institute (Investigator
Gravitational collapse with tachyon field and barotropic fluid
A particular class of space-time, with a tachyon field, \phi, and a
barotropic fluid constituting the matter content, is considered herein as a
model for gravitational collapse. For simplicity, the tachyon potential is
assumed to be of inverse square form i.e., V(\phi) \sim \phi^{-2}. Our purpose,
by making use of the specific kinematical features of the tachyon, which are
rather different from a standard scalar field, is to establish the several
types of asymptotic behavior that our matter content induces. Employing a
dynamical system analysis, complemented by a thorough numerical study, we find
classical solutions corresponding to a naked singularity or a black hole
formation. In particular, there is a subset where the fluid and tachyon
participate in an interesting tracking behaviour, depending sensitively on the
initial conditions for the energy densities of the tachyon field and barotropic
fluid. Two other classes of solutions are present, corresponding respectively,
to either a tachyon or a barotropic fluid regime. Which of these emerges as
dominant, will depend on the choice of the barotropic parameter, \gamma.
Furthermore, these collapsing scenarios both have as final state the formation
of a black hole.Comment: 18 pages, 7 figures. v3: minor changes. Final version to appear in
GR
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