WTC2005-63258 RESEARCH ON THE IDENTIFICATION METHODS OF FRICTION IN KINEMATICAL JOINTS OF MECHANICAL SYSTEMS

ABSTRACT This paper describes two approaches for the simultaneous identification of the coulomb and viscous parameters in kinematical joints. One is a time-domain method (TDM) and the other is a frequency-domain method (FDM). Simulation shows that both of the two methods have good performances in identifying friction at high SNR (90dB). But at low SNR (20dB), the estimation accuracy of the frequency-domain method is higher than that of the time-domain method. A field experiment employing a linkage mechanism driven by motor is also carried out. The experimental results obtained by the two approaches are almost identical under different experiment conditions. It has been concluded that the presented identification methods of friction in kinematical joints are correct and applicable. INTRODUCTION Kinematical joint is an absolutely necessary structural connection in mechanical systems. The kinematical joint is responsible for transferring energy to a remote site, and may change the type of motion, as needed. The characteristics of kinematical joints have been studied in many paper

Preparation and Photocatalytic Activity of Ag Modified Ti-Doped-Bi 2

Ti doped Bi2O3 (TDB) and Ag ion modified Ti doped Bi2O3 (Ag@TDB) photocatalysts were prepared by framework replacement synthesis method with different Ag loadings (0.05, 0.3, 0.75, and 1.0 mol/L AgNO3). The structural properties of the prepared catalysts were studied by scanning electron microscope (SEM), X-ray diffraction (XRD), BET surface area, and UV/Vis diffuse reflectance (DRS). The XRD spectra of the Ti doped Bi2O3 calcined at 650°C showed the diffraction peaks of a mixture of Bi12TiO20 and Bi4Ti3O12, with bits of mixed crystallite consisting of TiO2 and B2O3. A high blue shift in the range 650–550 nm was detected in the DRS band. This blue shift increased with the decreasing Ag content. The photocatalytic activities of the catalysts were evaluated for the degradation of crystal violet (CV) under UV light irradiation. The results indicated that the degradation rate of CV by using 1.0 mol/L AgNO3 doped bismuth titanate composite photocatalyst (1.0 Ag@TDB) was 1.9 times higher than that by using the bare Ti doped Bi2O3 photocatalyst. The higher activity of Ag@TDB is due to the enhancement of electron-hole pair separation by the electron trapping of silver particles

Unraveling the link between hypertension and depression in older adults: a meta-analysis

ObjectiveTo perform a meta-analyses to understand the current status of and risk factors for depression in older adults with hypertension.MethodsEight electronic databases and two clinical trial registries were searched to identify studies examining the incidence of and risk factors for depression among older adults with hypertension. The databases were searched from inception to June 2023. The included studies were evaluated using the Newcastle–Ottawa scale and the evaluation tool recommended by the Agency for Health care Research and Quality.ResultsA total of 18 studies with 29,694 patients were included. Meta-analysis results showed that the prevalence of depression in older adults with hypertension was 29%. The risk factors for depression among this population included sex [OR value 95% confidence interval 2.24 (1.32, 3.82)], education level [OR 95% CI 1.79 (1.02, 3.14)], residence [OR 95% CI 1.37 (1.24, 1.52)], comorbidities [OR 95% CI 1.79 (1.69, 1.90)], hypertension classification [OR 95% CI 2.81 (1.79, 4.42)], marital status [OR 95% CI 1.50 (1.33, 1.69)], sleep status [OR 95% CI 2.86 (2.21, 3.69)], activity limitation [OR 95% CI 3.42 (2.84, 4.13)], drinking [OR 95% CI 2.25 (1.58, 3.19)], social support [OR 95% CI 3.26 (2.42, 4.41)], living alone [OR 95% CI 1.79 (1.57, 2.04)], stressful events [OR 95% CI 1.62 (1.39, 1.90)], and course of diseases [OR 95% CI 3.23 (2.10, 4.97)].ConclusionThe incidence of depression in older adults with hypertension is high, and there are many risk factors. Clinical health care professionals should intervene early to target the above risk factors to reduce the incidence of depression in older adults with hypertension worldwide.Systematic review registrationPROSPERO (york.ac.uk), identifier [CRD42023417106]

17β-Estradiol Enhances Schwann Cell Differentiation via the ERβ-ERK1/2 Signaling Pathway and Promotes Remyelination in Injured Sciatic Nerves

Remyelination is critical for nerve regeneration. However, the molecular mechanism involved in remyelination is poorly understood. To explore the roles of 17β-estradiol (E2) for myelination in the peripheral nervous system, we used a co-culture model of rat dorsal root ganglion (DRG) explants and Schwann cells (SCs) and a regeneration model of the crushed sciatic nerves in ovariectomized (OVX) and non-ovariectomized (non-OVX) rats for in vitro and in vivo analysis. E2 promoted myelination by facilitating the differentiation of SCs in vitro, which could be inhibited by the estrogen receptors (ER) antagonist ICI182780, ERβ antagonist PHTPP, or ERK1/2 antagonist PD98059. This suggests that E2 accelerates SC differentiation via the ERβ-ERK1/2 signaling. Furthermore, E2 promotes remyelination in crushed sciatic nerves of both OVX and non-OVX rats. Interestingly, E2 also significantly increased the expression of the lysosome membrane proteins LAMP1 and myelin protein P0 in the regenerating nerves. Moreover, P0 has higher degree of colocalization with LAMP1 in the regenerating nerves. Taking together, our results suggest that E2 enhances Schwann cell differentiation and further myelination via the ERβ-ERK1/2 signaling and that E2 increases the expression of myelin proteins and lysosomes in SCs to promotes remyelination in regenerating sciatic nerves

The metagenome of the female upper reproductive tract

publishedVersio

DEP and AFO Regulate Reproductive Habit in Rice

Sexual reproduction is essential for the life cycle of most angiosperms. However, pseudovivipary is an important reproductive strategy in some grasses. In this mode of reproduction, asexual propagules are produced in place of sexual reproductive structures. However, the molecular mechanism of pseudovivipary still remains a mystery. In this work, we found three naturally occurring mutants in rice, namely, phoenix (pho), degenerative palea (dep), and abnormal floral organs (afo). Genetic analysis of them indicated that the stable pseudovivipary mutant pho was a double mutant containing both a Mendelian mutation in DEP and a non-Mendelian mutation in AFO. Further map-based cloning and microarray analysis revealed that dep mutant was caused by a genetic alteration in OsMADS15 while afo was caused by an epigenetic mutation in OsMADS1. Thus, OsMADS1 and OsMADS15 are both required to ensure sexual reproduction in rice and mutations of them lead to the switch of reproductive habit from sexual to asexual in rice. For the first time, our results reveal two regulators for sexual and asexual reproduction modes in flowering plants. In addition, our findings also make it possible to manipulate the reproductive strategy of plants, at least in rice

Morphological Plant Modeling: Unleashing Geometric and Topological Potential within the Plant Sciences

The geometries and topologies of leaves, flowers, roots, shoots, and their arrangements have fascinated plant biologists and mathematicians alike. As such, plant morphology is inherently mathematical in that it describes plant form and architecture with geometrical and topological techniques. Gaining an understanding of how to modify plant morphology, through molecular biology and breeding, aided by a mathematical perspective, is critical to improving agriculture, and the monitoring of ecosystems is vital to modeling a future with fewer natural resources. In this white paper, we begin with an overview in quantifying the form of plants and mathematical models of patterning in plants. We then explore the fundamental challenges that remain unanswered concerning plant morphology, from the barriers preventing the prediction of phenotype from genotype to modeling the movement of leaves in air streams. We end with a discussion concerning the education of plant morphology synthesizing biological and mathematical approaches and ways to facilitate research advances through outreach, cross-disciplinary training, and open science. Unleashing the potential of geometric and topological approaches in the plant sciences promises to transform our understanding of both plants and mathematics

Design of Flow Big Data System Based on Smart Pipeline Theory

As telecom operators to build intelligent pipe more and more, analysis and processing of big data technology to deal the huge amounts of data intelligent pipeline generated has become an inevitable trend. Intelligent pipe describes operational data, sales data; operator’s pipe flow data make the value for e-commerce business form and business model in mobile e-business environment. Intelligent pipe is the third dimension of 3 D pipeline mobile electronic commerce system. Intelligent operation dimensions make the mobile e-business three-dimensional artifacts. This paper discusses the smart pipeline theory, smart pipeline flow big data system, their system framework and core technology

Design of Flow Big Data System Based on Smart Pipeline Theory

As telecom operators to build intelligent pipe more and more, analysis and processing of big data technology to deal the huge amounts of data intelligent pipeline generated has become an inevitable trend. Intelligent pipe describes operational data, sales data; operator’s pipe flow data make the value for e-commerce business form and business model in mobile e-business environment. Intelligent pipe is the third dimension of 3 D pipeline mobile electronic commerce system. Intelligent operation dimensions make the mobile e-business three-dimensional artifacts. This paper discusses the smart pipeline theory, smart pipeline flow big data system, their system framework and core technology