Design and Study of Machine Tools for the Fly-Cutting of Ceramic-Copper Substrates

Ceramic-copper substrates, as high-power, load-bearing components, are widely used in new energy vehicles, electric locomotives, high-energy lasers, integrated circuits, and other fields. The service length will depend on the substrate’s copper-coated surface quality, which frequently achieved by utilising an abrasive strip polishing procedure on the substrate’s copper-coated surface. Precision diamond fly-cutting processing machine tools were made because of the low processing accuracy and inability to match the production line’s efficiency. An analysis of the fly-cutting machining principle and the structural makeup of the ceramic-copper substrate is the first step in creating a roughness prediction model based on a tool tip trajectory. This model demonstrates that a shift in the tool tip trajectory due to spindle runout error directly impacts the machined surface’s roughness. The device’s structural optimisation design is derived from the above analyses and implemented using finite element software. Modal and harmonic response analysis validated the machine’s gantry symmetrical structural layout, a parametric variable optimisation design optimised the machine tool’s overall dimensions, and simulation validated the fly-cutterring’s constituent parts. Enhancing the machine tool’s stability and motion accuracy requires using the LK-G5000 laser sensor to measure the guideway’s straightness. The result verified the machine tool’s design index, with the Z- and Y-axes’ straightness being better than 2.42 μm/800 mm and 2.32 μm/200 mm, respectively. Ultimately, the device’s machining accuracy was confirmed. Experiments with flying-cut machining on a 190 × 140 mm ceramic-copper substrate yielded a roughness of Sa9.058 nm. According to the experimental results, the developed machine tool can fulfil the design specifications

Serological Association of <i>Chlamydia pneumoniae</i> Infection with Age-Related Macular Degeneration: A Systematic Review and Meta-Analysis

<div><p>Background</p><p>We investigated the serological association of <i>Chlamydia pneumoniae</i> infection with age-related macular degeneration (AMD).</p><p>Methods</p><p>A systematic review and meta-analysis was performed. PubMed, Embase, Web of Science and the Association of Research in Vision and Ophthalmology abstracts were searched to identify studies investigating the serological association of <i>Chlamydia pneumoniae</i> infection with age-related macular degeneration. The quality of original studies was assessed using the Newcastle-Ottawa scale. Heterogeneity was explored with meta-regression. The odds ratios (ORs) and standardized mean differences (SMD) of <i>Chlamydia pneumoniae</i> infection between AMD patients and controls were pooled.</p><p>Results</p><p>In total, 9 studies met the inclusion criteria using the Newcastle-Ottawa scale scores ranging from 4 to 9. There was heterogeneity among studies due to a difference in the study designs and measurement of exposure to <i>Chlamydia pneumoniae</i> infection. The overall OR of <i>Chlamydia pneumoniae</i> infection with AMD was 1.11 (95% confidence interval: 0.78–1.57, <i>P</i> = 0.56). The overall SMD of antibody titer between AMD and control was 0.43 (95% confidence interval: −0.12 to 0.99, <i>P</i> = 0.13).</p><p>Conclusions</p><p>Evidence from the current published literature suggested no statistically significant association between <i>Chlamydia pneumoniae</i> infection and AMD.</p></div

Assessment of Quality of Methodology of the Studies Using the Newcastle-Ottawa Quality Assessment Scale.

<p>‘Y’ denotes ‘yes’ and ‘N’ denotes ‘no’. Quality items: 1) Definition of case; 2) Representativeness of the cases; 3) Selection of Controls; 4) Definition of Controls; 5) Study control for age; 6) Study controls for smoking; 7) Ascertainment of exposure; 8) Same method of ascertainment for cases and controls; 9) Non-response rate.</p

Characteristics of the Studies Included in the Meta-analysis of Association of <i>Chlamydia pneumoniae</i> with Age-related Macular Degeneration.

<p>AMD: age related macular degeneration; n: number; USA: United States of America; UK: United Kingdom; NA: not available; ELISA: Enzyme-linked immunosorbent assay; PCR: Polymerase chain reaction; MIF: Microimmunofluorescence; C.P. <i>Chlamydia pneumoniae</i>.</p

PRISMA flow diagram showing the result of literature screening for meta-analysis.

<p>PRISMA flow diagram showing the result of literature screening for meta-analysis.</p

Meta-analysis of the serologic association of with <i>Chlamydia pneumoniae</i> and the prevalence of AMD.

<p>A: Forest plot comparing the positive rate of <i>Chlamydia pneumoniae</i> infection between AMD cases and controls; squares indicate study-specific odds ratio (OR). B: Funnel plots for positive rate of <i>Chlamydia pneumoniae</i> infection between AMD cases and controls; C: Forest plot comparing the IgG antibody titers of <i>Chlamydia pneumoniae</i> infection between AMD cases and controls; squares indicate study-specific standardized mean difference (SMD). The size of the box is proportional to the weight of the study; horizontal lines indicate 95% confidence interval (CI); diamond indicates summary OR or SMD with its corresponding 95% CI.</p

Use of Modified Lignocellulosic Butanol Residue in Phenol-Resorcinol-Formaldehyde Polymers

Lignocellulosic butanol residue (BR), obtained as the by-product of lignocellulosic butanol production, was used for the preparation of lignin-based phenol-resorcinol-formaldehyde resins (LPRFRs) by condensation polymerization. The lignin was first phenolated under sodium hydroxide catalysis at 90 to 92 °C at various phenolation times (1.0 to 4.0 h). The structural differences between BR and phenolated BR (PBR) were studied using Fourier transform infrared (FT-IR) spectroscopy, ultraviolet (UV) spectroscopy, thermogravimetric analysis (TGA), and gel permeation chromatography (GPC). The BR phenolated for 3.0 h had high phenol hydroxyl content, low molecular weight, and good thermal stability. The LPRFRs with 30 wt.% BR had the lowest free formaldehyde and phenol. With the substitution of BR for phenol, the hydrophilicity of LPRFRs increased. In addition, the mechanical, fragility, thermal properties, and morphology of lignin-phenol-resorcinol-formaldehyde foams (LPRFFs) were also investigated. The LPRFFs had excellent comprehensive properties when 30 wt.% PBR was substituted for phenol. These experimental findings could provide a new avenue for further study and application of bio-phenol-resorcinol foams

Research on distresses detection, evaluation and maintenance decision-making for highway pavement in reconstruction and expansion project

Artificial walking survey, ground penetrating radar (GPR) and falling weight deflectometer (FWD) were used to test the actual condition of the highway pavement in reconstruction and expansion project for better maintenance decision-making. Therefore, a decision-making system with the application of four evaluation indexes including deflection value (DV), pavement surface condition within 20 m(PCI20), maintenance effect (ME) and internal crack rate (ICR) was constructed. Through the pavement empirical-mechanical calculation and the Delphi method analysis, the corresponding threshold for the DV, PCI20 and ICR were 27 (0.01 mm), 80, and 20 m/100 m2 respectively. Then, the decision-making system was applied for the 5.5 km section with the detection and evaluation results, and the advised maintenance plans of different lanes were determined. Lastly, the effect of the decision-making system was analyzed. Results show that the decision-making system can scientifically decide the treatment plans and save the maintenance cost by about 30.1 %. The deflection near the grouting holes significantly decreases resulting from the high-density cement slurry distribution. The milling and repaving have a high structural reinforcement ability of reducing deflection up to more than 66 %, which is positively related to the milling depth

Oceanographic consequences of the Bransfield Strait (Antarctica) opening

The Bransfield Strait (Antarctica) is an important region for evaluating changes in Weddell Sea shelf waters on geological time scales because of its restricted connections to the surrounding ocean. However, the detailed oceanographic consequences of the opening of the strait remain unclear. We present bottom-current-related sedimentary features in the Bransfield Strait and examine the impact of the strait’s opening on deep-water circulation. Our findings show that the ocean circulation started to resemble that of the present day after a period of volcanic activity, possibly around the Middle Pleistocene. Coeval changes in Bransfield Strait morphology and an increase in seafloor irregularities due to the formation of volcanic chains finally determined new pathways for the Bransfield deep and bottom waters, enhanced due to the new climatic scenario of 100 k.y. cycles. The fact that “modernlike” oceanic circulation occurred only during previous interglacial periods demonstrates the significant impact of 100 k.y. climate cycles on the thermohaline changes of Antarctic deep waters. Hence, establishing a modern-day circulation model would enable researchers to assess paleoproductivity and local upwelling that have profoundly influenced the marine ecosystem of the Antarctic Peninsula after the Middle Pleistocene3,61