► Flow behavior and microstructure were influenced by strain rate remarkably. ► DRX takes place easily at larger strain and higher deformation temperatures. ► Constitutive equations in this paper can ...characterize DRV and DRX. ► The equations can predict the flow behavior during whole deformation process. ► The equations consider the deformation heating, and the relative error is 5.73%.
The flow behavior of 7050 aluminum alloy was investigated by means of isothermal compression tests. Isothermal compression of 7050 aluminum alloy was carried out on a Gleeble-1500 thermal simulation machine at the deformation temperatures ranging from 593K to 743K, the strain rates ranging from 0.01s−1 to 20.0s−1, and the height reductions of 30%, 50% and 70%. The characteristics of stress–strain curves are determined by the interaction of work hardening, dynamic recovery and dynamic recrystallization. The flow stress decreases with the increasing of deformation temperature and the decreasing of strain rate. The relationship between microstructure and processing parameters was analyzed. The constitutive equations for characterizing the flow behavior during the whole deformation process had been established, based on the experimental results and the kinetic analysis. The average relative error between the calculated and the experimental flow stress is 5.73%, which indicates that the constitutive equations can be used to predict the flow behavior of 7050 aluminum alloy accurately during high temperature deformation.
The variety of Borrelia burgdorferi sensu lato (B. burgdorferi) genospecies leads to distinction in clinical manifestations of Lyme borreliosis (LB). There are reports of LB clinical characteristics ...in China, where the B. burgdorferi genospecies in ticks and animal hosts are different from those in Europe and North America. During May to September in 2010 and 2011, all patients who had erythema migrans (EM, more than 5 cm in diameter) after a recent tick-bite, and sought medical care at Mudanjiang Forestry Central Hospital, Heilongjiang Province of northeastern China, were enrolled in the study. Specific PCR was used to determine the B. burgdorferi genospecies in the disseminated patients. Of 265 EM patients, B. burgdorferi DNA was detected in blood specimens from 15 of 55 disseminated patients. Sequence analyses of 5S–23S rRNA, flagellin, ospC, 16S rRNA and ospA genes revealed that 11 patients were infected with Borrelia garinii, three with Borrelia afzelii and one with Borrelia valaisiana-related genospecies. Among 15 patients, 40%, 13.3% and 13.3% manifested pruritus, pain and ulceration, respectively. Systemic symptoms, arthralgia or a swollen joint and lymphadenopathy were observed in 26.7%, 13.3% and 6.7% patients, respectively. In northeastern China, three genospecies of LB patients were detected. The B. burgdorferi genospecies identified in this study was predominantly B. garinii. A case infected with B. valaisiana-related genospecies was reported for the first time.
► The flow stress decreases with temperature due to the dissolution of Cu, Mg, Zn particles and the occurrence of DRX. ► The presence of dispersoid particles such as Mn and Cr resists ...recrystallization by pinning of the grain boundaries. ► The
Q-values are about from 136.61
kJ
mol
−1 to 143.31
kJ
mol
−1 which is close to that self diffusion of pure aluminum. ► The peak efficiency of power dissipation at a strain of 0.7 is about 0.34 occurring at 713
K and 0.01
s
−1.
Isothermal compression tests of 7A09 aluminum alloy were carried out on a Gleeble-1500 simulator at the deformation temperatures ranging from 633
K to 733
K, the strain rates ranging from 0.01
s
−1 to 10.0
s
−1, and the height reductions ranging from 40% to 85%. Several modeling approaches, including the flow stress–strain curves, the kinetic analysis, the constitutive model and the processing maps, are used to characterize the deformation behavior in the isothermal compression of 7A09 aluminum alloy in this paper. The experimental results show that the flow stress in the isothermal compression of 7A09 alloy is significantly sensitive to the strain, the strain rate and the deformation temperature. The flow stress decreases with the increasing of deformation temperature due to the dissolution of intermetallic precipitates into Al matrix and the occurrence of selective DRX at higher deformation temperatures. And, it increases noticeably with the increasing of strain rate because of the increase in the rate of dislocation generation. The apparent activation energy for deformation (
Q) in the isothermal compression of 7A09 aluminum alloy varies slightly with the strain. The
Q-values are about from 136.61
kJ
mol
−1 to 143.31
kJ
mol
−1 which is close to that self diffusion in pure aluminum. The constitutive model in the isothermal compression of 7A09 aluminum alloy is developed using the Zener–Hollomon parameter in the exponent-type equation. The maximum relative error and minimum relative error between the calculated and the experimental flow stress are 6.67% and 0.07%, respectively. Finally, the processing maps at different strains with microstructural examination are established in the isothermal compression of 7A09 aluminum alloy. It is concluded that the effect of strain on the processing maps is significant. The peak efficiency of power dissipation at a strain of 0.7 is about 0.34 occurring at a deformation temperature of 713
K and strain rate of 0.01
s
−1, which is correspondent to an optimal deformation condition of 7A09 aluminum alloy.
Enterococcus faecalis is an important contributor to the persistence of chronic apical periodontitis. However, the mechanism by which E. faecalis infection in the root canals and dentinal tubules ...affects periapical tissue remains unclear. Bacterial extracellular vesicles (EVs) act as natural carriers of microbe-associated molecular patterns (MAMPs) and have recently attracted considerable attention. In this study, we investigated the role of EVs derived from E. faecalis in the pathogenesis of apical periodontitis. We observed that E. faecalis EVs can induce inflammatory bone destruction in the periapical areas of mice. Double-labeling immunofluorescence indicated that M1 macrophage infiltration was increased by E. faecalis EVs in apical lesions. Moreover, in vitro experiments demonstrated the internalization of E. faecalis EVs into macrophages. Macrophages tended to polarize toward the M1 profile after treatment with E. faecalis EVs. Pattern recognition receptors (PRRs) can recognize MAMPs of bacterial EVs and, in turn, trigger inflammatory responses. Thus, we performed further mechanistic exploration, which showed that E. faecalis EVs considerably increased the expression of NOD2, a cytoplasmic PRR, and that inhibition of NOD2 markedly reduced macrophage M1 polarization induced by E. faecalis EVs. RIPK2 ubiquitination is a major downstream of NOD2. We also observed increased RIPK2 ubiquitination in macrophages treated with E. faecalis EVs, and E. faecalis EV-induced macrophage M1 polarization was notably alleviated by the RIPK2 ubiquitination inhibitor. Our study revealed the potential for EVs to be considered a virulence factor of E. faecalis and found that E. faecalis EVs can promote macrophage M1 polarization via NOD2/RIPK2 signaling. To our knowledge, this is the first report to investigate apical periodontitis development from the perspective of bacterial vesicles and demonstrate the role and mechanism of E. faecalis EVs in macrophage polarization. This study expands our understanding of the pathogenic mechanism of E. faecalis and provides novel insights into the pathogenesis of apical periodontitis.
The strength of electrodeposited nanocrystalline Ni increased rather than decreased after annealing for 1 h at temperatures below 150
°C, with little change in the grain sizes or detectable impurity ...segregation. Annealing at 200
°C can be utilized to tailor the grain size distribution for improved ductility in combination with good strength. Further annealing at above 250
°C, however, induced a transition to brittle behavior due to impurity segregation to grain boundaries concurrent with grain growth.
The disappearance of reactor
ν
¯
e
observed by the Daya Bay experiment is examined in the framework of a model in which the neutrino is described by a wave packet with a relative intrinsic momentum ...dispersion
σ
rel
. Three pairs of nuclear reactors and eight antineutrino detectors, each with good energy resolution, distributed among three experimental halls, supply a high-statistics sample of
ν
¯
e
acquired at nine different baselines. This provides a unique platform to test the effects which arise from the wave packet treatment of neutrino oscillation. The modified survival probability formula was used to fit Daya Bay data, providing the first experimental limits:
2.38
×
10
-
17
<
σ
rel
<
0.23
. Treating the dimensions of the reactor cores and detectors as constraints, the limits are improved:
10
-
14
≲
σ
rel
<
0.23
, and an upper limit of
σ
rel
<
0.20
(which corresponds to
σ
x
≳
10
-
11
cm
) is obtained. All limits correspond to a 95% C.L. Furthermore, the effect due to the wave packet nature of neutrino oscillation is found to be insignificant for reactor antineutrinos detected by the Daya Bay experiment thus ensuring an unbiased measurement of the oscillation parameters
sin
2
2
θ
13
and
Δ
m
32
2
within the plane wave model.
Abstract
Modal analysis is the vital prerequisite of the full-scale fatigue test of the wind turbine blade. In order to resolve the difficulty in solving the characteristic equation of the transfer ...matrix method in modal analysis, a method of solving the characteristic equation based on particle swarm optimization is proposed. Firstly, the beam model is used to simplify and discrete the blade along the spanwise of the blade. A concept of average bending stiffness is used for the elasticity assignment with beam segment, and the blade kinematics model is established. Subsequently, a designed particle swarm optimization is used to solve the characteristic equation. Finally, the proposed method is verified by modal analysis of an MW-scale blade. On this basis, the effect of the mass and position of the counterweight on the mode shape is investigated. The results indicate that the proposed method can provide a theoretical reference for the fatigue test technology of wind turbine blades.
Mechanical alloying has been used to form nanocomposite in an Al-20 wt%Sn alloy to promote its sliding wear performance, in particular the high load-carrying capability. X-ray diffraction and ...scanning electron microscopy characterization reveal that the nanocomposite is a structure of nanoscaled Sn particles distributed homogeneously in nanocrystalline Al matrix with typical size of the both smaller than 100 nm. The dry sliding wear performance, in particular at higher load, of the alloys prepared by mechanical alloying increases significantly comparing with that obtained by conventional powder metallurgy, and the optimal one was obtained by sintered at 723 K. This is due to the formation of uniform tin oxide layer on worn surface and better strength of the nanocomposite alloys. The wear mechanism of mechanical alloyed Al-20 wt%Sn alloys changes from delamination under lower sintering temperature to plastic flow and work hardening under higher sintering temperature.
Patients with multiple myeloma progressing on current therapies have limited treatment options. Pomalidomide (CC4047), an immunomodulatory drug, has significant activity in relapsed myeloma and ...previous studies suggest activity in lenalidomide refractory disease. To better define its efficacy in this group, we treated a cohort of lenalidomide refractory patients. Pomalidomide was given orally (2 mg) daily, continuously in 28-day cycles along with dexamethasone (40 mg) given weekly. Responses were assessed by the International Myeloma Working Group Criteria. Thirty-four patients were enrolled. The best response was very good partial response in 3 (9%), partial response (PR) in 8 (23%), best responses (MR) in 5 (15%), stable disease in 12 (35%) and progressive disease in 6 (18%), for an overall response rate of 47%. Of the 14 patients that were considered high risk, 8 (57%) had responses including 4 PR and 4 MR. The median time to response was 2 months and response duration was 9.1 months, respectively. The median overall survival was 13.9 months. Toxicity was primarily hematologic, with grade 3 or 4 toxicity seen in 18 patients (53%) consisting of anemia (12%), thrombocytopenia (9%) and neutropenia (26%). The combination of pomalidomide and dexamethasone (Pom/dex) is highly active and well tolerated in patients with lenalidomide-refractory myeloma.
Although not a new concept, modular construction has been the target of increasing interest and investment in recent years. Modular wood construction systems have economic and environmental ...advantages, as wood is a natural and locally available raw material with interesting thermal properties. In this context, the BlueWoodenHouse Project, a closed cooperation project between academy and industry, aims to improve the actual knowledge of modular wood construction in Portugal. Among other objectives, the project aims to characterize the solutions, systems, and materials used in wooden modular construction, specifically in a modular wooden, single-family house in full use. Afterward, the house was monitored for 1 year (temperature, relative humidity, and CO2) and the data collected were analyzed and the interior thermal comfort was evaluated. The results of CO2 concentration monitoring indicate adequate air renewal rates, except for some periods in the bedroom, during the night. Additionally, application of the adaptive comfort model proposed by the EN 16798-2 standard resulted in a percentage of time in discomfort due to overcooling ranging between 31.3% and 38.6%. However, most of these periods may correspond to times when there is no occupancy of these spaces.
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