To find the weak link of the structural stiffness is important to improve machine tool stiffness. However, how to overcome the static deformation with difficulty acquisition is a difficult problem in machine tool structure. The article takes the cantilever beam structure as a numerical example, the weak link is modeled as EA reduction in stiffness. Thorough finite element simulations are performed to assess the robustness and limitations of the method in several scenarios with single and multiple weaknesses. The sensors are used to acquire the acceleration data, the structural modal parameters are obtained by the singular value decomposition technique, and the dynamic characteristics are systematically reconstructed by using the modal state-space method to obtain static stiffness. Then, an identification method proposed by measured data and reconstructed data to identify the weak link of stiffness of the cantilever structure. Furthermore, the comparison of numerical and experimental results validate the correctness and effectiveness of this method. The research has certain practical engineering value and provides an accurate guidance for the optimization of machine tool stiffness.
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http://dx.doi.org/10.1177/0036850420952671 | DOI Listing |
BMC Public Health
December 2024
Department of Health Statistics, School of Public Health, Shanxi Medical University, 56 XinJian South Road Street, Taiyuan, Shanxi, China.
Background: The accelerated aging process worldwide is placing a heavy burden on countries. PM particulate matter exposure is a significant factor affecting human health and is crucial in the aging process.
Methods: We utilized data from China Health and Retirement Longitudinal Study (CHARLS) and the Survey of Health, Aging, and Retirement in Europe (SHARE) to study the relationship between PM exposure and the frailty index.
J Pediatr Surg
December 2024
Pediatric Surgery, Dipartimento di Medicina di Precisione e Rigenerativa a Area Jonica, Azienda Ospedaliera-Universitaria Consorziale Ospedale Pediatrico Giovanni XXIII, Bari, Italy.
Background And Aims: Image Defined Risk Factors (IDRFs) assess surgical risk in neuroblastoma (NB) and guide neoadjuvant therapy. Despite chemotherapy IDRFs may persist in 70 % of cases. Several studies have suggested that not all IDRFs hold equal significance and that the presence of an IDRF does not inherently signify unresectability.
View Article and Find Full Text PDFGenet Test Mol Biomarkers
December 2024
SRM Dental College, Bharathi Salai, Chennai, India.
Periodontal disease worsens glycemic control due to the bidirectional link between periodontitis and type 2 diabetes mellitus (T2DM), involving inflammatory markers such as soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK), tumor necrosis factor-α (TNF-α), and omentin-1. However, their combined role in T2DM with periodontitis has not been studied. This study aimed to evaluate the levels of these biomarkers in periodontitis patients with T2DM before and after nonsurgical periodontal therapy (NSPT).
View Article and Find Full Text PDFJ Clin Endocrinol Metab
December 2024
Division of Endocrinology and Metabolism, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, South Korea.
Context: Experimental evidence indicates that resistin, an adipokine, negatively impacts muscle metabolism by hindering myogenesis.
Objective: To explore resistin's potential as a biomarker of muscle health in humans by examining the relationship between circulating resistin levels and sarcopenia in older adults.
Design And Setting: A case-control study conducted in a geriatric clinical unit.
Arthroplast Today
December 2024
Department of Orthopedic Surgery, Vanderbilt University, Nashville, TN, USA.
Background: Aseptic loosening is the most common aseptic failure modality following total knee arthroplasty. Recent literature suggests that the implant-cement interface is the "weak-link" in fixation and lipid contamination may drive this debonding pattern. Therefore, the purpose of this study was to determine if the "double-butter" technique would significantly decrease lipid contamination of the tibial tray.
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