We consider global in time solutions of the Navier-Stokes-Fourier system describing the motion of a general compressible, viscous and heat conducting fluid far from equilibirum. Using a new concept ...of weak solution suitable to accommodate the inhomogeneous Dirichlet time dependent data we find sufficient conditions for the global in time weak solutions to be ultimately bounded.
The construction of weak solutions to compressible Navier–Stokes equations via a numerical method (including a rigorous proof of the convergence) is in a short supply, and so far, available only for ...one sole numerical scheme suggested in Karper (Numer Math, 125(3):441–510, 2013) for the no slip boundary conditions and the isentropic pressure with adiabatic coefficient
γ
>
3
. Here we consider the same problem for the general non zero inflow–outflow boundary conditions, which is definitely more appropriate setting from the point of view of applications, but which is essentially more involved as far as the existence of weak solutions is concerned. There is a few recent proofs of existence of weak solutions in this setting, but none of them is performed via a numerical method. The goal of this paper is to fill this gap. The existence of weak solutions on the continuous level requires several tools of functional and harmonic analysis and differential geometry whose numerical counterparts are not known. Our main strategy therefore consists in rewriting of the numerical scheme in its variational form modulo remainders and to apply and/or to adapt to the new variational formulation the tools developed in the theoretical analysis. In addition to the result, which is new, the synergy between numerical and theoretical analysis is the main originality of the present paper.
The purpose of this study is to investigate the clinical effects of platelet-rich plasma (PRP) and adipose-derived mesenchymal stem cell (MSC) as the fundamental treatment of osteoarthritis (OA).
...Twenty four Beagle dogs were used as cranial cruciate ligament transection models. The dogs were divided into four groups (n = 6) according to the intra-articular injection materials: the control group with phosphate-buffered saline (PBS), the PRP group with PRP, the MSC group with MSCs emerged in PBS, and the MSC and PRP co-treatment (MP) group with MSCs and PRP.
Lameness score, focal compression strength, articular extracellular matrix (ECM) compositions, histopathology, and real-time PCR were used to evaluate the effects of PRP and MSCs on canine OA. In the order of MP, PRP, and MSC group, these all showed positive effects on the evaluated categories. The lameness scores were lower, and the focal compression strengths of the affected femoral articular surface cartilages were higher than those in the OA control group. Also, the inflammatory changes, when evaluated with Mankin scoring and histomorphologic examination, were significantly ameliorated with the treatment of PRP and/or MSCs. The glycosaminoglycan and collagen composition of extracellular matrix was more favorable in the test groups. The ECM-related genes significantly increased through the up-regulation, while the protein expressions of inflammatory cytokines were decreased through the inhibitory effects of PRP and MSCs on chondrocyte apoptosis and inflammatory cytokines.
Taken together, this study suggests that PRP and MSCs treatments have a beneficial effect on OA via the stimulation of ECM synthesis and chondrocyte proliferation and via the inhibition of inflammatory reaction.
Ultraviolet (UV) B exposure induces DNA damage and production of reactive oxygen species (ROS), which causes skin photoaging through signaling pathways of inflammation and modulation of extracellular ...matrix remodeling proteins, collagens, and matrix metalloproteinase (MMP). As low molecular-weight fucoidan (LMF) has potential antioxidant and anti-inflammatory properties, we examined the protective effects of LMF against UVB-induced photoaging. A UVB-irradiated mouse model was topically treated with myricetin or LMF at 2.0, 1.0 and 0.2 mg/cm² (LMF2.0, LMF1.0 and LMF0.2, respectively) once a day for 15 weeks. Wrinkle formation, inflammation, oxidative stress, MMP expression, and apoptosis in the treated regions were compared with those in a distilled water-treated photoaging model (UVB control). LMF treatments, particularly LMF2.0 and LMF1.0, significantly inhibited the wrinkle formation, skin edema, and neutrophil recruitment into the photo-damaged lesions, compared with those in the UVB control. While LMF decreased interleukin (IL)-1β release, it increased IL-10. The LMF treatment inhibited the oxidative stresses (malondialdehyde and superoxide anion) and enhanced endogenous antioxidants (glutathione). Additionally, LMF reduced the mRNA expression of MMP-1, 9, and 13. The histopathological analyses revealed the anti-photoaging effects of LMF exerted via its antioxidant, anti-apoptotic, and MMP-9-inhibiting effects. These suggest that LMF can be used as a skin-protective remedy for photoaging.
Although three-dimensional (3D) printing of tungsten parts by Powder Bed Fusion (PBF) has been demonstrated by multiple research groups, a directed energy deposition (DED) process for fabricating ...pure tungsten structures has never been reported. This work reports successful fabrication of pure tungsten structures by DED, revealing the required process conditions. The effect of laser power, scan speed, powder feed rate and carrier gas velocity on the stability and properties of the structures is first analyzed, based on which the proper process condition for effective 3D printing of tungsten parts is proposed. Fabrication of a rectangular tube of 110 mm in height is demonstrated using an in-house DED printing system. Analyses of the fabricated samples show that the density and the hardness can be as high as 18.9 g/cm
3
(98.4% of the theoretical value) and 3.9 GPa, respectively. The results indicate that the optimal condition for 3D printing of tungsten is 400 ~ 530 J/mm
2
in terms of specific energy and that high-speed or high-mass injection of powder can induce waviness on the surface. This work suggests that DED can be a promising alternative to produce pure tungsten parts in various applications.
The majority of catastrophic wheelset failures are caused by surface opening fatigue cracks in either the wheel tread or wheel inner. Since failures in railway wheelsets can cause disasters, regular ...inspections to check for defects in wheels and axles are mandatory. Currently, ultrasonic testing, acoustic emissions, and the eddy current testing method are regularly used to check railway wheelsets in service. Yet, in many cases, despite surface and subsurface defects of the railroad wheels developing, the defects are not clearly detected by the conventional non-destructive inspection system. In the present study, a new technique was applied to the detection of surface and subsurface defects in railway wheel material. The results indicate that the technique can detect surface and subsurface defects of railway wheel specimens using the distribution of the alternating current (AC) electromagnetic field. In the wheelset cases presented, surface cracks with depths of 0.5 mm could be detected using this method.
We identify a class
maximal
dissipative solutions to models of compressible viscous fluids that maximize the energy dissipation rate. Then we show that any maximal dissipative solution approaches an ...equilibrium state for large times.
Abstract
We study convergence of a mixed finite element-finite volume scheme for the compressible Navier–Stokes equations in the isentropic regime under the full range $1<\gamma <\infty $ of the ...adiabatic coefficients $\gamma $ for the problem with general nonzero inflow–outflow boundary conditions. We propose a modification of Karper’s scheme (2013, A convergent FEM-DG method for the compressible Navier–Stokes equations. Numer. Math., 125, 441–510) in order to accommodate the nonzero boundary data, prove existence of its solutions, establish the stability and uniform estimates, derive a convenient consistency formulation of the balance laws and use it to show the weak convergence of the numerical solutions to a dissipative solution with the Reynolds defect introduced in Abbatiello et al. (2021, Generalized solutions to models of compressible viscous fluids. Discrete Contin. Dyn. Syst., 41, 1--28). If the target system admits a strong solution then the convergence is strong towards the strong solution. Moreover, we establish the convergence rate of the strong convergence in terms of the size of the space discretization $h$ (which is supposed to be comparable with the time step $\varDelta t$). In the case of the nonzero inflow–outflow boundary data all results are new. The latter result is new also for the no-slip boundary conditions and adiabatic coefficients $\gamma $ less than the threshold $3/2$.
In this paper we study the asymptotic limits of a compressible two-fluid model in an unbounded domain Ω with general initial data. By applying refined related entropy method and carrying out detailed ...analysis on the oscillations of velocity, we derive rigorously that the dissipative turbulent solutions (velocity) of the compressible two-fluid model converge to the strong solution of the quasi-geostropic equation when there is a Coriolis force and Ω=R2×T1, and while the two-fluid model has no Coriolis force term and Ω=R3, its solutions converge to the strong solution of incompressible Euler equations.
Obesity increases the risks of metabolic syndromes including nonalcoholic fatty liver disease (NAFLD), diabetic dyslipidemia, and chronic kidney disease. Dietary krill oil (KO) has shown antioxidant ...and anti-inflammatory properties, thereby being a therapeutic potential for obesity-induced metabolic syndromes. Thus, the effects of KO on lipid metabolic alteration were examined in a high-fat diet (HFD)-fed mice model. The HFD model (n = 10 per group) received an oral gavage with distilled water as a control, metformin at 250 mg/kg, and KO at 400, 200, and 100 mg/kg for 12 weeks. The HFD-induced weight gain and fat deposition were significantly reduced in the KO treatments compared with the control. Blood levels were lower in parameters for NAFLD (e.g., alanine aminotransferase, and triglyceride), type 2 diabetes (e.g., glucose and insulin), and renal dysfunction (e.g., blood urea nitrogen and creatinine) by the KO treatments. The KO inhibited lipid synthesis through the modification of gene expressions in the liver and adipose tissues and adipokine-mediated pathways. Furthermore, KO showed hepatic antioxidant activities and glucose lowering effects. Histopathological analyses revealed that the KO ameliorated the hepatic steatosis, pancreatic endocrine/exocrine alteration, adipose tissue hypertrophy, and renal steatosis. These analyses suggest that KO may be promising for inhibiting obesity and metabolic syndromes.
PDF
