191 research outputs found
Multi-objective optimization for the geometry of trapezoidal corrugated morphing skins
Morphing concepts have great importance for the design of future aircraft as they provide the opportunity for the aircraft to adapt their shape in flight so as to always match the optimal configuration. This enables the aircraft to have a better performance, such as reducing fuel consumption, toxic emissions and noise pollution or increasing the maneuverability of the aircraft. However the requirements of morphing aircraft are conflicting from the structural perspective. For instance the design of a morphing skin is a key issue since it must be stiff to withstand the aerodynamic loads, but flexible to enable the large shape changes. Corrugated sheets have remarkable anisotropic characteristics. As a candidate skin for a morphing wing, they are stiff to withstand the aerodynamic loads and flexible to enable the morphing deformations. This work presents novel insights into the multi-objective optimization of a trapezoidal corrugated core with elastomer coating. The geometric parameters of the coated composite corrugated panels are optimized to minimize the in-plane stiffness and the weight of the skin and to maximize the flexural out-of-plane stiffness of the skin. These objective functions were calculated by use of an equivalent finite element code. The gradient-based aggregate method is selected to solve the optimization problem and is validated by comparing to the GA multi-objective optimization technique. The trend of the optimized objectives and parameters are discussed in detail; for example the optimum corrugation often has the maximum corrugation height. The obtained results provide important insights into the design of morphing corrugated skins
Critical behavior and phase transition of dilaton black holes with nonlinear electrodynamics
In this paper, we take into account the dilaton black hole solutions of
Einstein gravity in the presence of logarithmic and exponential forms of
nonlinear electrodynamics. At first, we consider the cosmological constant and
nonlinear parameter as thermodynamic quantities which can vary. We obtain
thermodynamic quantities of the system such as pressure, temperature and Gibbs
free energy in an extended phase space. We complete the analogy of the
nonlinear dilaton black holes with Van der Waals liquid-gas system. We work in
the canonical ensemble and hence we treat the charge of the black hole as an
external fixed parameter. Moreover, we calculate the critical values of
temperature, volume and pressure and show they depend on dilaton coupling
constant as well as nonlinear parameter. We also investigate the critical
exponents and find that they are universal and independent of the dilaton and
nonlinear parameters, which is an expected result. {Finally, we explore the
phase transition of nonlinear dilaton black holes by studying the Gibbs free
energy of the system. We find that in case of , we have no phase
transition. When , the system admits a second order phase transition,
while for the system experiences a first order transition.
Interestingly, for we observe a \textit{zeroth order} phase
transition in the presence of dilaton field. This novel \textit{zeroth order}
phase transition is occurred due to a finite jump in Gibbs free energy which is
generated by dilaton-electromagnetic coupling constant, , for a certain
range of pressure.
Lorentzian Wormholes in Lovelock Gravity
In this paper, we introduce the -dimensional Lorentzian wormhole solutions
of third order Lovelock gravity. In contrast to Einstein gravity and as in the
case of Gauss-Bonnet gravity, we find that the wormhole throat radius, ,
has a lower limit that depends on the Lovelock coefficients, the dimensionality
of the spacetime and the shape function. We study the conditions of having
normal matter near the throat, and find that the matter near the throat can be
normal for the region , where depends on
the Lovelock coefficients and the shape function. We also find that the third
order Lovelock term with negative coupling constant enlarges the radius of the
region of normal matter, and conclude that the higher order Lovelock terms with
negative coupling constants enlarge the region of normal matter near the
throat.Comment: 13 pages, 5 figure
Commissioning of the electron injector for the AWAKE experiment
The advanced wakefield experiment (AWAKE) at CERN is the first proton beam-driven plasma wakefield acceleration experiment. The main goal of AWAKE RUN 1 was to demonstrate seeded self-modulation (SSM) of the proton beam and electron witness beam acceleration in the plasma wakefield. For the AWAKE experiment, a 10-meter-long Rubidium-vapor cell together with a high-power laser for ionization was used to generate the plasma. The plasma wakefield is driven by a 400 GeV/c proton beam extracted from the super proton synchrotron (SPS), which undergoes a seeded self-modulation process in the plasma. The electron witness beam used to probe the wakefields is generated from an S-band RF photo-cathode gun and then accelerated by a booster structure up to energies between 16 and 20 MeV. The first run of the AWAKE experiment revealed that the maximum energy gain after the plasma cell is 2 GeV, and the SSM mechanism of the proton beam was verified. In this paper, we will present the details of the AWAKE electron injector. A comparison of the measured electron beam parameters, such as beam size, energy, and normalized emittance, with the simulation results was performed
Population pharmacokinetics of liposomal irinotecan in patients with cancer and exposure–safety analyses in patients with metastatic pancreatic cancer
Pharmacokinetics; Liposomal irinotecan; SafetyFarmacocinética; Irinotecán liposomal; SeguridadFarmacocinètica; Irinotecan liposomal; SeguretatLiposomal irinotecan is a liposomal formulation of irinotecan, which prolongs circulation of irinotecan and its active metabolite SN-38. A population pharmacokinetic (PK) model was developed based on data from seven studies (N = 440). Adequacy of the model was assessed using multiple methods, including visual predictive check. Associations between PK exposure and the incidence of diarrhea (grade ≥3) and neutropenia adverse events (AEs) (grade ≥3) at first event in patients with metastatic pancreatic ductal adenocarcinoma (mPDAC) were investigated using logistic regression based on data from two studies (the phase III NAPOLI-1 [N = 260] and phase I/II NCT02551991 [N = 56] trials). The PKs of total irinotecan was described by a two-compartment model with first-order elimination, with SN-38 formed directly by a first-order constant from the central compartment of irinotecan or after using a transit compartment. Clearance was 17.9 L/week (0.107 L/h) and 19,800 L/week (118 L/h) for total irinotecan and SN-38, respectively. The UGT1A1*28 7/7 homozygous genotype had no significant impact on SN-38 clearance. Model evaluation was satisfactory for both irinotecan and SN-38. The incidence of diarrhea (grade ≥3) at first event was significantly higher with increasing average concentrations of total irinotecan and SN-38; there was no significant association between an increased risk of neutropenia AEs (grade ≥3) at first event and average SN-38 concentrations. In summary, the PKs of total irinotecan and SN-38 after administration of liposomal irinotecan were well-described by the model. The UGT1A1*28 status had no significant impact on the PKs of liposomal irinotecan
Fuzzy finite element model updating of the DLR AIRMOD test structure
This article presents the application of finite-element fuzzy model updating to the DLR AIRMOD structure. The proposed approach is initially demonstrated on a simulated mass-spring system with three degrees of freedom. Considering the effect of the assembly process on variability measurements, modal tests were carried out for the repeatedly disassembled and reassembled DLR AIRMOD structure. The histograms of the measured data attributed to the uncertainty of the structural components in terms of mass and stiffness are utilised to obtain the membership functions of the chosen fuzzy outputs and to determine the updated membership functions of the uncertain input parameters represented by fuzzy variables. In this regard, a fuzzy parameter is introduced to represent a set of interval parameters through the membership function, and a meta model (kriging, in this work) is used to speed up the updating. The use of non-probabilistic models, i.e. interval and fuzzy models, for updating models with uncertainties is often more practical when the large quantities of test data that are necessary for probabilistic model updating are unavailable
Computational analysis and design of an aerofoil with morphing tail for improved aerodynamic performance in transonic regime
This article focuses on the aerodynamic design of a morphing aerofoil at cruise conditions using computational fluid dynamics (CFD). The morphing aerofoil has been analysed at a Mach number of 0.8 and Reynolds number of 3×106 , which represents the transonic cruise speed of a commercial aircraft. In this research, the NACA0012 aerofoil has been identified as the baseline aerofoil where the analysis has been performed under steady conditions at a range of angles of attack between 0∘ and 3.86∘ . The performance of the baseline case has been compared to the morphing aerofoil for different morphing deflections ( wte/c=[0.005−0.1] ) and start of the morphing locations ( xs/c=[0.65−0.80] ). Further, the location of the shock wave on the upper surface has also been investigated due to concerns about the structural integrity of the morphing part of the aerofoil. Based upon this investigation, a most favourable morphed geometry has been presented that offers both, a significant increase in the lift-to-drag ratio against its un-morphed counterpart and has a shock location upstream of the start of the morphing part
Seizure Clusters, Seizure Severity Markers, and SUDEP Risk.
Rationale: Seizure clusters may be related to Sudden Unexpected Death in Epilepsy (SUDEP). Two or more generalized convulsive seizures (GCS) were captured during video electroencephalography in 7/11 (64%) patients with monitored SUDEP in the MORTEMUS study. It follows that seizure clusters may be associated with epilepsy severity and possibly with SUDEP risk. We aimed to determine if electroclinical seizure features worsen from seizure to seizure within a cluster and possible associations between GCS clusters, markers of seizure severity, and SUDEP risk. Methods: Patients were consecutive, prospectively consented participants with drug-resistant epilepsy from a multi-center study. Seizure clusters were defined as two or more GCS in a 24-h period during the recording of prolonged video-electroencephalography in the Epilepsy monitoring unit (EMU). We measured heart rate variability (HRV), pulse oximetry, plethysmography, postictal generalized electroencephalographic suppression (PGES), and electroencephalography (EEG) recovery duration. A linear mixed effects model was used to study the difference between the first and subsequent seizures, with a level of significance set at p < 0.05. Results: We identified 112 GCS clusters in 105 patients with 285 seizures. GCS lasted on average 48.7 ± 19 s (mean 49, range 2-137). PGES emerged in 184 (64.6%) seizures and postconvulsive central apnea (PCCA) was present in 38 (13.3%) seizures. Changes in seizure features from seizure to seizure such as seizure and convulsive phase durations appeared random. In grouped analysis, some seizure features underwent significant deterioration, whereas others improved. Clonic phase and postconvulsive central apnea (PCCA) were significantly shorter in the fourth seizure compared to the first. By contrast, duration of decerebrate posturing and ictal central apnea were longer. Four SUDEP cases in the cluster cohort were reported on follow-up. Conclusion: Seizure clusters show variable changes from seizure to seizure. Although clusters may reflect epilepsy severity, they alone may be unrelated to SUDEP risk. We suggest a stochastic nature to SUDEP occurrence, where seizure clusters may be more likely to contribute to SUDEP if an underlying progressive tendency toward SUDEP has matured toward a critical SUDEP threshold
Current perspectives on bone metastases in castrate-resistant prostate cancer
Prostate cancer is the most frequent noncutaneous cancer occurring in men. On average, men with localized prostate cancer have
a high 10-year survival rate, and many can be cured. However, men with metastatic castrate-resistant prostate cancer have
incurable disease with poor survival despite intensive therapy. This unmet need has led to recent advances in therapy aimed at
treating bone metastases resulting from prostate cancer. The bone microenvironment lends itself to metastases in castrate-resistant
prostate cancer, as a result of complex interactions between the microenvironment and tumor cells. The development of 223radium
dichloride (Ra-223) to treat symptomatic bone metastases has improved survival in men with metastatic castrate-resistant
prostate cancer. Moreover, Ra-223 may have effects on the tumor microenvironment that enhance its activity. Ra-223 treatment
has been shown to prolong survival, and its effects on the immune system are under investigation. Because prostate cancer affects
a sizable portion of the adult male population, understanding how it metastasizes to bone is an important step in advancing
therapy. Clinical trials that are underway should yield new information on whether Ra-223 synergizes effectively with immunotherapy
agents and whether Ra-223 has enhancing effects on the immune system in patients with prostate cancer
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