Improvement, the Performance of Polyurethane (PUR), Y-290 Resin as Coating of Oil Pipeline by Using Multi-Walled Carbon Nanotubes (MWCNTs)

In this study, polyurethane epoxy-Y290 (PUR-Y290) as a matrix material was reinforced by 1%MWCNTs. Polyurethane is a thermoset polymer and using for several applications particularly as coatings of gas and oil pipeline. Polyurethane uses as a liquid coating against the corrosion, and that is caused by the direct exposure for long periods of UV irradiation and humidity. The nanocomposites were prepared by adding 1wt% MWCNTs to polyurethane and mixed by using an ultrasound mixer. Polyueethane-1%MWCNTs composite sample was exposed to accelerate weathering (UV irradiation coming from sunlight, moisture, and salt water spray) during the exposure to different durations 6 months, 12 months and 24 months. Exposed and unexposed samples were investigated and evaluated by thermal and mechanical tests.It was found that the incorporation 1.0%wt of MWCNTs filler, enhanced the thermal stability and improved the mechanical properties during the exposure for long-term life to accelerated weathering conditions, compared with polyurethane coating without MWCNTs filler. These results indicated that polyurethane (liquid coating) nanocomposites have a higher resistance to environmental condition and give more protective against corrosion of oil pipelines and applied as coatings by spray method to protect the oil pipeline surfaces from environmental conditions

Optimal Design and Operation of an Industrial Three Phase Reactor for the Oxidation of Phenol

YesAmong several treatment methods Catalytic Wet Air Oxidation (CWAO) treatment is considered as a useful and powerful method for removing phenol from waste waters. In this work, mathematical model of a trickle bed reactor (TBR) undergoing CWAO of phenol is developed and the best kinetic parameters of the relevant reaction are estimated based on experimental data (from the literature) using parameter estimation technique. The validated model is then utilized for further simulation and optimization of the process. Finally, the TBR is scaled up to predict the behavior of CWAO of phenol in industrial reactors. The optimal operating conditions based on maximum conversion and minimum cost in addition to the optimal distribution of the catalyst bed is considered in scaling up and the optimal ratio of the reactor length to reactor diameter is calculated with taking into account the hydrodynamic factors (radial and axial concentration and temperature distribution)

Modified Equations to Calculate Water Content and Refractive Index of Honey Based on Its Total Soluble Solids

The capacity of honey to break light is used for refractometric determination of humidity. In the present work, a manual refractometer was used to measure honey total soluble solids (73% - 86%) which are the corresponding values of refractive indices stated in Chataway’s Table. The relationship between values of total soluble solids, water content and refractive index in the obtained graphics gave equations that could be used directly to calculate both refractive index and water content of honey from its total soluble solids. This simple, fast and easy way could be applied without utilizing expensive refractometers due to their high cost or lack of their usage training. Furthermore, the suggested equation is more accurate than that of the current reference table (i.e. Chataway’s Table) and could be rapidly utilized for calculating water content in honey samples

Intelligent Coordination of Traditional Power Plants and Inverters Air Conditioners Controlled With Feedback-Corrected MPC in LFC

Demand response programs have been receiving more serious attention as alternatives for participating in load frequency control. Inverter air conditioners (IAC) are acknowledged as suitable devices for demand response due to their increasing contribution to network consumption. Despite their potential, their use presents challenges, including delayed responses, variable interference, and the absence of coordination with traditional generation units, which may affect control performance. Also, existing control strategies fail to consider operational and physical constraints, resulting in possible model mismatches. In this paper, a model predictive control with feedback correction (MPCFC) is proposed to dispatch control signals to the IACs so they can effectively participate in the frequency control of an interconnected power system. The feedback correction method is presented to enhance prediction accuracy in the MPC and weaken the influence of model parameter mismatches and external disturbances. Furthermore, to minimize the impacts of communication delays on frequency overshoot/undershoot, this study introduces an intelligent supervisory coordinator based on an artificial neural network to coordinate the reaction of traditional generation units and IACs to correct significant frequency variations brought on by the time delays. The effectiveness of the developed control scheme is verified through numerical studies by comparing it with the IAC with PI and MPC controllers (without coordinator) and the system without IACs. Case studies are investigated on a two-area power system in MATLAB/Simulink environment, and the OPAL-RT real-time simulator is used to validate the results.</p

Nuttier Bubbles

We construct new explicit solutions of general relativity from double analytic continuations of Taub-NUT spacetimes. This generalizes previous studies of 4-dimensional nutty bubbles. One 5-dimensional locally asymptotically AdS solution in particular has a special conformal boundary structure of $AdS_3\times S^1$. We compute its boundary stress tensor and relate it to the properties of the dual field theory. Interestingly enough, we also find consistent 6-dimensional bubble solutions that have only one timelike direction. The existence of such spacetimes with non-trivial topology is closely related to the existence of the Taub-NUT(-AdS) solutions with more than one NUT charge. Finally, we begin an investigation of generating new solutions from Taub-NUT spacetimes and nuttier bubbles. Using the so-called Hopf duality, we provide new explicit time-dependent backgrounds in six dimensions.Comment: 32 pages, 1 figure; v.3. typos corrected. Matches the published versio

The frequency of transforming growth factor-TGF-B gene polymorphisms in a normal southern Iranian population

Several single nucleotide polymorphisms (SNPs) of the transforming growth factor-β1 gene (TGFB1) have been reported. Determination of TGFB1 SNPs allele frequencies in different ethnic groups is useful for both population genetic analyses and association studies with immunological diseases. In this study, five SNPs of TGFB1 were determined in 325 individuals from a normal southern Iranian population using polymerase chain reaction-restriction fragment length polymorphism method. This population was in Hardy-Weinberg equilibrium for these SNPs. Of the 12 constructed haplotypes, GTCGC and GCTGC were the most frequent in the normal southern Iranian population. Comparison of genotype and allele frequencies of TGFB SNPs between Iranian and other populations (meta-analysis) showed significant differences, and in this case the southern Iranian population seems genetically similar to Caucasoid populations. However, neighbour-joining tree using Nei's genetic distances based on TGF-β1 allele frequencies showed that southern Iranians are genetically far from people from the USA, Germany, UK, Denmark and the Czech Republic. In conclusion, this is the first report of the distribution of TGFB1 SNPs in an Iranian population and the results of this investigation may provide useful information for both population genetic and disease studies. © 2008 The Authors

Gravitational quasinormal modes of AdS black branes in d spacetime dimensions

The AdS/CFT duality has established a mapping between quantities in the bulk AdS black-hole physics and observables in a boundary finite-temperature field theory. Such a relationship appears to be valid for an arbitrary number of spacetime dimensions, extrapolating the original formulations of Maldacena's correspondence. In the same sense properties like the hydrodynamic behavior of AdS black-hole fluctuations have been proved to be universal. We investigate in this work the complete quasinormal spectra of gravitational perturbations of $d$-dimensional plane-symmetric AdS black holes (black branes). Holographically the frequencies of the quasinormal modes correspond to the poles of two-point correlation functions of the field-theory stress-energy tensor. The important issue of the correct boundary condition to be imposed on the gauge-invariant perturbation fields at the AdS boundary is studied and elucidated in a fully $d$-dimensional context. We obtain the dispersion relations of the first few modes in the low-, intermediate- and high-wavenumber regimes. The sound-wave (shear-mode) behavior of scalar (vector)-type low-frequency quasinormal mode is analytically and numerically confirmed. These results are found employing both a power series method and a direct numerical integration scheme.Comment: added references, typos corrected, minor changes, final version for JHE

Grain Surface Models and Data for Astrochemistry

AbstractThe cross-disciplinary field of astrochemistry exists to understand the formation, destruction, and survival of molecules in astrophysical environments. Molecules in space are synthesized via a large variety of gas-phase reactions, and reactions on dust-grain surfaces, where the surface acts as a catalyst. A broad consensus has been reached in the astrochemistry community on how to suitably treat gas-phase processes in models, and also on how to present the necessary reaction data in databases; however, no such consensus has yet been reached for grain-surface processes. A team of ∼25 experts covering observational, laboratory and theoretical (astro)chemistry met in summer of 2014 at the Lorentz Center in Leiden with the aim to provide solutions for this problem and to review the current state-of-the-art of grain surface models, both in terms of technical implementation into models as well as the most up-to-date information available from experiments and chemical computations. This review builds on the results of this workshop and gives an outlook for future directions

Search for microscopic black hole signatures at the Large Hadron Collider

This is the Pre-Print version of the Article. The official published paper can be accessed from the link below - Copyright @ 2011 ElsevierA search for microscopic black hole production and decay in pp collisions at a center-of-mass energy of 7 TeV has been conducted by the CMS Collaboration at the LHC, using a data sample corresponding to an integrated luminosity of 35 inverse picobarns. Events with large total transverse energy are analyzed for the presence of multiple high-energy jets, leptons, and photons, typical of a signal expected from a microscopic black hole. Good agreement with the expected standard model backgrounds, dominated by QCD multijet production, is observed for various final-state multiplicities. Limits on the minimum black hole mass are set, in the range 3.5 -- 4.5 TeV, for a variety of parameters in a model with large extra dimensions, along with model-independent limits on new physics in these final states. These are the first direct limits on black hole production at a particle accelerator.This work is supported by the FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia); Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF and WCU (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTD (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)