Search

In order to solve the problem that the selection of key process parameters of a flexible soldering robot depends on manual experience, the empirical model of its THT assembly process parameters is established with the response surface method and the reliability of the model is verified. On this basis, the multi-parameter relative sensitivity of the key process parameters is analyzed through the Monte-Carlo simulation, and their single-parameter sensitivity curve is drawn. Then, based on the sensitivity analysis, the stability region division method is designed, and the stability region of process parameters for soldering quality comprehensive score is obtained. The optimal region of process parameters of the soldering robot are acquired by compressing the stability region: soldering temperature from 350-368 ℃, soldering time from 1.31-1.48 s and solder feeding volume from 1.5-2.0 mm3. The average value of the soldering quality comprehensive score within the optimal region of process parameters is 90.2 points.

Soil properties, the chemical composition of cementation solution, injection technique, and environmental conditions have all been extensively studied as variables influencing microbially induced carbonate precipitation performance. However, despite the fact that different researchers have used different bacterial suspensions, the influence of bacterial suspension type, more specifically some organic matters in bacterial suspensions, which can play a key role in the morphology and mechanical properties of CaC[O.sub.3], has often been overlooked. In this study, the harvested bacterial solutions were centrifuged to separate bacterial cells and supernatant. The precipitated cells were then diluted with three distinct solutions: supernatant (RB), fresh culture medium (FB), and 0.9% NaCl solution (NB), which were subsequently utilized to stabilize the sand. The results indicated that the bacterial suspension type could greatly impact the strength of biocemented sand, particularly coarse and medium sand. Differences in unconfined compressive strength can be related to differences in precipitated CaC[O.sub.3] microstructures, morphologies, and compositions, which were examined using scanning electron microscopy, X-ray diffraction analysis, and Fourier transform infrared spectroscopy. Key words: microbially induced calcite precipitation (MICP), unconfined compressive strength (UCS), bacterial suspension type, microstructure Les proprietes du sol, la composition chimique de la solution de cimentation, la technique d'injection et les conditions environnementales ont toutes ete largement etudiees comme variables influencant les performances du MICP. Cependant, malgre le fait que differents chercheurs aient utilise differentes suspensions bacteriennes, l'influence du type de suspension bacterienne, plus precisement de certaines matieres organiques dans les suspensions bacteriennes, qui peuvent jouer un role cle dans la morphologie et les proprietes mecaniques du CaC[O.sub.3], a souvent ete negligee. Dans cette etude, les solutions bacteriennes recoltees ont ete centrifugees pour separer les cellules bacteriennes et le surnageant. Les cellules precipitees ont ensuite ete diluees dans trois solutions distinctes : surnageant (RB), milieu de culture frais (FB) et solution de NaCl a 0,9% (NB), qui ont ensuite ete utilises pour stabiliser le sable. Les resultats ont indique que le type de suspension bacterienne pouvait avoir un impact important sur la resistance du sable biocimente, en particulier le sable grossier et moyen. Les differences de NGC peuvent etre liees aux differences de microstructures, de morphologies et de compositions du CaC[O.sub.3] precipite, qui ont ete examinees a l'aide de la microscopie electronique a balayage (MEB), de l'analyse par diffraction des rayons X (DRX) et de la spectroscopie infrarouge transformee de Fourier (IRTF). [Traduit par la Redaction] Mots-cles : precipitation de calcite induite par les microbes (MICP), resistance a la compression non confinee (UCS), type de suspension bacterienne, microstructure, Introduction The microbially induced carbonate precipitation (MICP)-based soil improvement approach has been introduced to geotechnical engineering for decades. Several studies have been conducted to investigate the performance of MICP in [...]

The negative effects of obesity and excess body fat on bone mineral density (BMD) have been widely reported. As opposed to waist circumference (WC) or body mass index (BMI), weight-adjusted waist index (WWI) is a superior method for assessing obesity. WWI also indicates centripetal obesity independently of the weight of the individual. An investigation of WWI and adolescents' BMD was conducted in this study. The National Health and Nutrition Examination Survey (NHANES) 2011–2018 provided the data for this cross-sectional investigation. In this study, weighted multivariate logit models were employed to assess the correlation between teenage BMD and WWI. Additionally, we conducted interaction tests and subgroup analysis. Through multivariate linear regression, we discovered that WWI was negatively linked with lumbar, trunk, and total BMD but not pelvis BMD in this study, which included 6828 subjects. We found that each unit increase in WWI resulted in a lumbar BMD decline of 0.04 g/cm2 (95%CI −0.04, −0.04), a trunk BMD decrease of 0.03 g/cm2 (95%CI −0.03, −0.02), and a total BMD decrease of 0.02 g/cm2 (95%CI −0.02, −0.02). In conclusion, in US teenagers, there were negative connections discovered between WWI and lumbar, trunk, and total BMD, but not pelvis BMD. [ABSTRACT FROM AUTHOR]