Study on the Universal Tapered Segmental Ring Assembly Simulation Algorithm and Deviation Assessment: A Case Study on Metro Line Tunnel

Universal tapered segmental ring system has been adopted to assemble tangent and curve line elements into the shield tunnels through the relative rotation of the adjacent front and rear rings, which simplifies the formwork design, demonstrates strong universality, and is easy for quality assurance. To evaluate the position deviation caused by the taper value and propose the assembly scheme for the contractor, this article developed the universal tapered segmental ring assembly simulation technology. Firstly, the assembly procedure of the universal tapered segmental ring system both in normal case and in special case is introduced, including the interval tunnel of special rings and actual engineering that needs deviation correction. Secondly, relevant core algorithms are introduced in detail, including the coordinate position algorithm of horizontal and vertical curves and computer graphic algorithm of spatial point rotating around any axis. Finally, this article takes a background metro line tunnel as a case to validate the algorithm and illustrate the assessment methodology of universal tapered segmental ring assembly accuracy. The sections with maximum deviation are found as an alert ahead of the shield advancing. In conclusion, the algorithms and methodology proposed in this article illustrate the excellent suitability and robustness in shield tunnels adopting a universal tapered segmental ring system in the stage of both design and construction.

Analysis of lacrimal duct morphology from cone-beam CT dacryocystography in a Japanese population

Dacryocystorhinostomy (DCR) is the first-line treatment for lacrimal duct stenosis and obstruction in western countries. Endoscopic-assisted nasolacrimal duct intubation (ENDI) is spreading steadily as a minimally invasive treatment in Northeast Asia. ENDI is prevalent in this area because Northeast Asians have relatively flat facial features, with a less elevated superior orbital rim than other ethnic groups. This allows for relatively easy manipulation of a dacryoendoscope. Evidence has accumulated that the morphology and inclination of the lacrimal duct differ among individuals and ethnic groups. In this study, we collected anthropometric data from a Japanese population of 100 samples—the parameters vital for designing a dacryoendoscope probe. The data we provided was essential in designing the overall length, bending point, and curve-line of the dacryoendoscope probe. Although the Japanese data measured in this study would not be directly applicable to other ethnic groups, we hope that the parameters provided by this study will contribute to the accumulation of valuable anthropometric data for the design of endoscopic probe morphologies and the development of therapeutic devices for lacrimal tract diseases—in terms of designing optimal morphologies, specific to ethnic groups and populations.

The correlation of duration of cervical flexion per day with neck disability index scores in office workers: a cross sectional study

Background: An increasing number of office workers complain of neck pain after extended smart phone use. We conducted this study to examine the correlation between the duration of cervical flexion per day (DCF) during smart phone use and neck disability index scores (NDI) scores of office workers in China.Methods: In this cross-sectional study, 1791 individuals responded to an on line questionnaire. For our study, we included responses of 498 [27.8%] office workers. Excluded from the study were 1293 [72.9%] individuals including building workers, students, non-office workers, and those who did not complete the questionnaire. Participants completed an online questionnaire survey from May 29, 2019 to April 10, 2020. The NDI scores were used to evaluate cervical symptoms. Linear regression, threshold saturation effect analysis, t-test, and Pearson’s chi-square tests were used to analyze the data.Results: We analyzed questionnaire results of the 498 office workers. The t-test showed no significant differences among the gender groups for age, working age, and NDI scores (P>0.05). While low back pain had a strong correlation with NDI scores [β (95%CI):2.40 (1.49, 3.31), P <0.0001]. When adjusting for age, working age, and low back pain covariates, DCF had a positive correlation with NDI scores. In addition, DCF had a curve line correlation with NDI scores-a monotone increasing relationship; the fold point was 6 (P<0.05).Conclusions: DCF had a positive curve line correlation with the NDI scores suggesting that office workers should limit DCF to a maximum of 6 hours to decrease NDI scores.

The correlation of duration of cervical flexion per day with neck disability index scores in office workers: a cross sectional study

Background: An increasing number of office workers complain of neck pain after extended smart phone use. We conducted this study to examine the correlation between the duration of cervical flexion per day (DCF) during smart phone use and neck disability index scores (NDI) scores of office workers in China.Methods: In this cross-sectional study, 1791 individuals responded to an on line questionnaire. For our study, we included responses of 498 [27.8%] office workers. Excluded from the study were 1293 [72.9%] individuals including building workers, students, non-office workers, and those who did not complete the questionnaire. Participants completed an online questionnaire survey from May 29, 2019 to April 10, 2020. The NDI scores were used to evaluate cervical symptoms. Liner regression, threshold saturation effect analysis, t-test, and Pearson’s chi-square tests were used to analyze the data. Results: We analyzed questionnaire results of the 498 office workers. The t-test showed no significant differences among the gender groups for age, working age, and NDI scores (P>0.05).] while low back pain had a strong correlation with NDI scores [β (95%CI):2.40 (1.49, 3.31), P <0.0001]. When adjusting for age, working age, and low back pain covariates, DCF had a positive correlation with NDI scores. In addition, DCF had a curve line correlation with NDI scores-a monotone increasing relationship; the fold point was 6 (P<0.05).Conclusions: DCF had a positive curve line correlation with the NDI scores suggesting that office workers should limit DCF to a maximum of 6 hours to decrease NDI scores.

Establishing the Velocity of M-Protein Decline (VMD) Value in Response to Multiple Myeloma Therapy That Best Predicts M-Protein of Zero

Introduction: Serum M-protein levels, measured by serum immunoelectrophoresis, have been one of the major tests that determine the type of response to therapy in Multiple Myeloma. Achieving an M-protein of zero is one of the criteria determining complete remission which in turn translates into longer progression-free survival and overall survival. Triplet therapy tends to be the standard therapeutic approach in younger, fit, and transplant candidates. However, in older non-fit patients many oncologists start with doublets and only escalate to triplet combinations upon less optimal response. The predictive value of the velocity of the M-spike decline (VMD) has not been adequately studied. We conducted this study to find the optimal VMD that predicts a serum M-protein of zero. Methods: A sample of mostly non-fit older Multiple Myeloma patients was identified. All patients had regular serum protein electrophoresis with M-protein levels documented every 4-8 weeks until they achieved M-protein levels of zero, plateauing without attaining the target of zero, or rebounding with progression. Best-fit line or curve was constructed and the slope of the decline was calculated. VMD was defined as the slope of the best fit-curve/line. VMD values corresponding to the binary outcomes of achieving or failing to achieve an M-protein value of zero were collected. A ROC curve was constructed to determine the cut-off VMD value that best predicts the outcome of M-protein of zero. Results: A total of 47 patients of mostly non-fit older Multiple Myeloma patients were included in our final sample. The median age of the sample was 71 years. Thirteen percent had triplet therapy. Thirty four percent had proteasome inhibitor based combinations while 64% had IMiD based combinations. Fifty seven percent achieved the target M-protein level of zero while 43% failed. The area under the ROC curve, AUC, was 0.98 (p&lt;0.0001). The cut-off VMD value (the slope of the best fit M-protein curve/line) which best predicts an outcome of M-protein of zero was &lt; -0.276 with a corresponding sensitivity of 89% and specificity of 100%. Conclusions: This exploratory study established the VMD value that best predicts the outcome of M-protein of zero in response to Multiple Myeloma therapy. This may be potentially used by oncologists to make early decisions regarding the need for further optimization or intensification of their therapeutic combinations as they treat their older non-fit Multiple Myeloma patients. Disclosures No relevant conflicts of interest to declare.

The correlation of duration of cervical flexion per day with neck disability index scores in office workers: a cross sectional study

Background: An increasing number of office workers complain of neck pain after extended smart phone use. We conducted this study to examine the correlation between the duration of cervical flexion per day (DCF) during smart phone use and neck disability index scores (NDI ) scores of office workers in China.Methods: In this cohort study, 1791 individuals responded to an on line questionnaire. For our study, we included responses of 498 [27.8%] office workers. Excluded from the study were 1293 [72.9%] individuals including building workers, students, non-office workers, and those who did not complete the questionnaire. Participants completed an online questionnaire survey from May 29, 2019 to April 10, 2020. The NDI was used to evaluate cervical symptoms. Multivariable logistic regression, threshold saturation effect analysis, t-test, and Pearson’s chi-square tests were used to analyze the data. Results: We analyzed questionnaire results of the 498 office workers. The t-test showed no significant differences among the gender groups for age, working age, and NDI scores (P>0.05). Compared with other activities, smart phone use had no positive correlation with NDI scores (P>0.05), while low back pain had a strong correlation with NDI scores (P<0.05). When adjusting for age, working age, and low back pain covariates, DCF had a positive correlation with NDI scores. In addition, DCF had a curve line correlation with NDI-a monotone increasing relationship; the fold point was 6 (P<0.05).Conclusions: DCF had a positive curve line correlation with the NDI suggesting that office workers should limit DCF to a maximum of 6 hours to decrease NDI scores.

The Dynamic Performance Analysis of a Low-Floor Tram Hydraulic Anti-Kink System Based on Multidisciplinary Collaboration

According to the basic principle of the hydraulic anti-kink system and flow continuity equation, this paper takes the low-floor tram as the research object and the four vehicles as the research carrier. Based on the correlation parameters between the vehicle subsystem and the hydraulic subsystem, a co-simulation platform of a low-floor tram with hydraulic an anti-kink system is built. The co-simulation results show that the anti-kink system can well maintain the relative yaw angle consistency between the vehicle body and bogie. The anti-kink system restrains the maximum yaw angle and excessive lateral displacement of the vehicle body effectively. The consistency between the experiment results and the simulation results shows the accuracy of the model. The co-simulation model of the low-floor tram with hydraulic anti-kink system can be used to research the dynamic performance when it passes through curve line.

The Correlation of Time of Cervical Flexion with Cervical Symptoms in Office Workers: A Cohort Study

Background: An increasing number of office workers complain of neck pain after extended smart phone use. We conducted this study to examine the correlation between the time of cervical flexion (CFI) during smart phone use and cervical symptoms of office workers in China.Methods: In this cohort study, 1791 individuals responded to an on line questionnaire. For our study, we included responses of 498 [27.8%] office workers. Excluded from the study were 1293 [72.9%] individuals including building workers, students, non-office workers, and those who did not complete the questionnaire. Participants completed an online questionnaire survey from May 29, 2019 to April 10, 2020. The (Neck Disability Index) NDI was used to evaluate cervical symptoms. Multivariable logistic regression, threshold saturation effect analysis, t-test, and Pearson’s chi-square tests were used to analyze the data. Results: We analyzed questionnaire results of the 498 office workers. The t-test showed no significant differences among the gender groups for age, working age, and NDI scores (P>0.05). Compared with other activities, smart phone use had no positive correlation with NDI scores (P>0.05), while low back pain had a strong correlation with NDI scores (P<0.05). When adjusting for age, working age, and low back pain covariates, CFI had a positive correlation with NDI scores. In addition, CFI had a curve line correlation with NDI-a monotone increasing relationship; the fold point was 6 (P<0.05).Conclusions: CFI had a positive curve line correlation with the NDI suggesting that office workers should limit CFI to a maximum of 6 hours to decrease cervical symptoms.

A method for inspecting the cleanliness of spinneret holes

At present, computer vision system is widely used for the cleanliness inspection for spinneret holes, but it has a high misjudgment rate for many holes with small dirt. In this paper, a method is proposed to improve the accuracy of the cleanliness inspection. The method has four sequential phases. First, the closed contour curve of a standard hole and its curvature are extracted. Based on double-threshold segmentation of the contour curve, line and arc segments are segmented to generate a closed piecewise curve model. Second, the model is fitted to the closed contour curve L1 of the hole to be inspected based on a nonlinear least squares principle, and the distance curve that represents the shortest distance between the closed piecewise curve L2 constructed from the aligned model and L1 is calculated based on the nearest neighbor search algorithm. Third, the dirt detection curve L3 is generated from the distance curve weighted by a blended weighting curve. Final, based on a global threshold combining with unevenness elimination of L3, the cleanliness index is calculated based on the segmentation and location of dirt, and is used to judge whether the hole is qualified or not. The experimental results of four databases demonstrate that, the proposed method provides better performance compared with the traditional method.

Impact of Engine Oil’s Additives on Particulate Matter’s Micro-and Nanostructure Using Electron Microscopy Image Analysis

According to increasingly stringent emission regulations on particle emissions from automotive vehicles, a diesel engine must be equipped with diesel particulate filter (DPF) to trap the particulate matters (PMs) which can be harmful to human health. Morphology and chemical composition of particulate matters were successfully studied using electron microscopy and electron dispersive x-ray spectroscopy (EDS) analysis. Microstructure of particulate matters derived from diesel blending lubricating oil were not significant different compared to diesel PM. Nanostructure of soot is a spherical shape composed of curve line crystallites and the particle sizes were in the range of 10 – 60 nm while the metal oxide ash is composed of lattice fringes. Chemical composition analysis of EDS result showed that metallic additives from lubricating oil cannot be burned during combustion and might be transformed into metal oxide ash.