Application of modal and harmonic analysis to predict the automotive transmission vibration at an early stage of design

Trudy NAMI ◽  
2021 ◽  
pp. 30-36
Author(s):  
D. S. Novikov

Introduction (problem statement and relevance). The need to increase the operating speeds and input torque of automobile transmissions because of their vibration is becoming a more and more urgent problem.The purpose of the study was to substantiate the applicability of harmonic analysis, which makes it possible to determine the actual values of vibration values during a steady oscillatory process, for the initial assessment of the gearbox vibration activity.Methodology and research methods. The calculation of the gearbox vibration activity was carried out by modal and harmonic analyses, implemented by the finite element method, and followed by the experimental study of gearbox vibration on a test bench.Scientific novelty and results. The presented experimental and calculated results of the research show that the difference between the experimental and calculated values is no more than 4.2%. This proves the possibility of applying modal and harmonic analysis to predict the gearbox vibration state at an early stage of product design at the stand.Practical significance. The given calculation algorithm makes it possible to predict, with a sufficient degree of accuracy, the vibration of the gearbox before the manufacture of a prototype in experimental production.

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Thomas J. Wilkinson ◽  
Daniel G. D. Nixon ◽  
Jared Palmer ◽  
Courtney J. Lightfoot ◽  
Alice C. Smith

Abstract Background Those living with kidney disease (KD) report extensive symptom burden. However, research into how symptoms change across stages is limited. The aims of this study were to 1) describe symptom burden across disease trajectory, and 2) to explore whether symptom burden is unique to KD when compared to a non-KD population. Methods Participants aged > 18 years with a known diagnosis of KD (including haemodialysis (HD) and peritoneal dialysis (PD)) and with a kidney transplant) completed the Leicester Kidney Symptom Questionnaire (KSQ). A non-KD group was recruited as a comparative group. Multinominal logistic regression modelling was used to test the difference in likelihood of those with KD reporting each symptom. Results In total, 2279 participants were included in the final analysis (age 56.0 (17.8) years, 48% male). The main findings can be summarised as: 1) the number of symptoms increases as KD severity progresses; 2) those with early stage KD have a comparable number of symptoms to those without KD; 3) apart from those receiving PD, the most frequently reported symptom across every other group, including the non-KD group, was ‘feeling tired’; and 4) being female independently increased the likelihood of reporting more symptoms. Conclusions Our findings have important implications for patients with KD. We have shown that high symptom burden is prevalent across the spectrum of disease, and present novel data on symptoms experienced in those without KD. Symptoms requiring the most immediate attention given their high prevalence may include pain and fatigue. Trial registration The study was registered prospectively as ISRCTN11596292.


Author(s):  
Yifan Zhang ◽  
S. Thomas Ng

AbstractPublic transport networks (PTNs) are critical in populated and rapidly densifying cities such as Hong Kong, Beijing, Shanghai, Mumbai, and Tokyo. Public transportation plays an indispensable role in urban resilience with an integrated, complex, and dynamically changeable network structure. Consequently, identifying and quantifying node criticality in complex PTNs is of great practical significance to improve network robustness from damage. Despite the proposition of various node criticality criteria to address this problem, few succeeded in more comprehensive aspects. Therefore, this paper presents an efficient and thorough ranking method, that is, entropy weight method (EWM)–technology for order preference by similarity to an ideal solution (TOPSIS), named EWM–TOPSIS, to evaluate node criticality by taking into account various node features in complex networks. Then we demonstrate it on the Mass Transit Railway (MTR) in Hong Kong by removing and recovering the top k critical nodes in descending order to compare the effectiveness of degree centrality (DC), betweenness centrality (BC), closeness centrality (CC), and the proposed EWM–TOPSIS method. Four evaluation indicators, that is, the frequency of nodes with the same ranking (F), the global network efficiency (E), the size of the largest connected component (LCC), and the average path length (APL), are computed to compare the performance of the four methods and measure network robustness under different designed attack and recovery strategies. The results demonstrate that the EWM–TOPSIS method has more obvious advantages than the others, especially in the early stage.


2013 ◽  
Vol 664 ◽  
pp. 94-98
Author(s):  
Guang De Zhang

Following deepened exploration and development in Shengli exploration area, seismic data requirements are also getting higher and higher. However, in recent years the difference of Xiaoqing river on both sides have made us know that the importance of this problem. In view of the above, this task is aimed at quaternary shallow of old river course within Xiaoqing River. Our analysis of lithology and sedimentary characteristics are using static cone penetration test and rock core exploration method, and we want to reappear near surface deposition of old river course within Xiaoqing River. The research is close combined with the exploration demand and theoretical study, so it has important theoretical and practical significance.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Huan-Hua Xu ◽  
Zhen-Hong Jiang ◽  
Cong-Shu Huang ◽  
Yu-Ting Sun ◽  
Long-Long Xu ◽  
...  

Abstract Background OPD and OPD' are the two main active components of Ophiopogon japonicas in Shenmai injection (SMI). Being isomers of each other, they are supposed to have similar pharmacological activities, but the actual situation is complicated. The difference of hemolytic behavior between OPD and OPD' in vivo and in vitro was discovered and reported by our group for the first time. In vitro, only OPD' showed hemolysis reaction, while in vivo, both OPD and OPD' caused hemolysis. In vitro, the primary cause of hemolysis has been confirmed to be related to the difference between physical and chemical properties of OPD and OPD'. In vivo, although there is a possible explanation for this phenomenon, the one is that OPD is bio-transformed into OPD' or its analogues in vivo, the other one is that both OPD and OPD' were metabolized into more activated forms for hemolysis. However, the mechanism of hemolysis in vivo is still unclear, especially the existing literature are still difficult to explain why OPD shows the inconsistent hemolysis behavior in vivo and in vitro. Therefore, the study of hemolysis of OPD and OPD' in vivo is of great practical significance in response to the increase of adverse events of SMI. Methods Aiming at the hemolysis in vivo, this manuscript adopted untargeted metabolomics and lipidomics technology to preliminarily explore the changes of plasma metabolites and lipids of OPD- and OPD'-treated rats. Metabolomics and lipidomics analyses were performed on ultra-high performance liquid chromatography (UPLC) system tandem with different mass spectrometers (MS) and different columns respectively. Multivariate statistical approaches such as principal component analysis (PCA) and orthogonal partial least square-discriminant analysis (OPLS-DA) were applied to screen the differential metabolites and lipids. Results Both OPD and OPD' groups experienced hemolysis, Changes in endogenous differential metabolites and differential lipids, enrichment of differential metabolic pathways, and correlation analysis of differential metabolites and lipids all indicated that the causes of hemolysis by OPD and OPD' were closely related to the interference of phospholipid metabolism. Conclusions This study provided a comprehensive description of metabolomics and lipidomics changes between OPD- and OPD'-treated rats, it would add to the knowledge base of the field, which also provided scientific guidance for the subsequent mechanism research. However, the underlying mechanism require further research.


2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Lei Wang ◽  
Jiehui Zheng ◽  
Shenwei Huang ◽  
Haoye Sun

Our study aims to contrast the neural temporal features of early stage of decision making in the context of risk and ambiguity. In monetary gambles under ambiguous or risky conditions, 12 participants were asked to make a decision to bet or not, with the event-related potentials (ERPs) recorded meantime. The proportion of choosing to bet in ambiguous condition was significantly lower than that in risky condition. An ERP component identified as P300 was found. The P300 amplitude elicited in risky condition was significantly larger than that in ambiguous condition. The lower bet rate in ambiguous condition and the smaller P300 amplitude elicited by ambiguous stimuli revealed that people showed much more aversion in the ambiguous condition than in the risky condition. The ERP results may suggest that decision making under ambiguity occupies higher working memory and recalls more past experience while decision making under risk mainly mobilizes attentional resources to calculate current information. These findings extended the current understanding of underlying mechanism for early assessment stage of decision making and explored the difference between the decision making under risk and ambiguity.


2021 ◽  
Author(s):  
Ling-Yu Chu ◽  
Jian-Yuan Zhou ◽  
Yi-Xuan Zhao ◽  
Yan-Ting Ou ◽  
Tian Yang ◽  
...  

Background:Esophagogastric junction tumor (EGJ) is a rare but fatal disease with a rapid rising incidence worldwide in the late 20 years, and it lacks a convenient and safe method for diagnosis. This study aimed to evaluate the potential of serum CYR61 as a biomarker for the diagnosis of EGJ tumor. Methods: Enzyme-linked immunosorbent assay (ELISA) was used to estimate CYR61 levels in sera of 152 EGJ tumor patients and 137 normal controls. Receiver operating characteristics (ROC) was carried out to evaluate the diagnostic accuracy. The Mann–Whitney’s U test was used to compare the difference of serum levels of CYR61 between groups. And chi-square tests were employed to estimate the correlation of the positive rate of serum CYR61 between/among subgroups. Results: Serum CYR61 levels were statistically lower in EGJ tumor and early-stage EGJ tumor patients than those in normal controls (P<0.0001). The sensitivity, specificity, and the area under the curve (AUC) of this biomarker in EGJ tumor were 88.2%, 43.8% and 0.691, respectively, and those for early stage of EGJ tumor were 80.0%, 66.4% and 0.722, respectively. Analyses showed that there was no correlation between the clinical data and the levels of CYR61 (P>0.05). Conclusion: This study showed that CYR61 might be a potential biomarker to assist the diagnosis of EGJ tumor.


2012 ◽  
Vol 5 ◽  
pp. 271-276
Author(s):  
Shu Ren Zhang ◽  
Zhong Long Li

The mesh reinforcement technique of polymer mortar wire rope is a new reinforcement technique used more in the domestic fittest reinforcement project recent years. Recently, there is no unified technical standards, the detailed practice is not same in practical work. There are big differences among the reinforcement effects. The key issue of wire rope is whether add prestressed or not. If add, how much should be prestressed? The difference of the actual practice and reinforcement effect reflects the understanding gap polymer mortar wire rope of mesh reinforcement technique action principle of the designer. A correct understanding of polymer mortar wire rope of mesh reinforcement technique the mechanism and the objective analysis strengthening effect and actively explore research in engineering application problems have a practical significance to promote the healthy development of the structure strengthening technology.


Author(s):  
Wei Shan ◽  
Jingyi Wang

This research aims to explore the interaction between environmental performance and employment China’s manufacturing industries. Based on the environmental performance of 32 industries in China’s manufacturing industry during 2006–2015, a panel vector autoregressive model was constructed to study the interaction between industry output and employment in clean industries and dirty industries. The dynamic impact and internal transmission mechanism between environmental performance is analyzed. The study found that in the early stage, due to the reduction of production scale, there was a weak and short-term negative correlation effect on employment, and the mutual promotion relationship between economic benefits and employment was unsustainable. In return, employment affects environmental performance, but the effect differs due to the different forms of environmental performance. For dirty industries, the impact of environmental performance on employment through technical effects is more significant and, thus, a win–win situation of ecological environment and employment stability will be achieved. This research has practical significance regarding how to scientifically and effectively carry out environmental regulation and green management.


Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3524
Author(s):  
János Gera ◽  
Gábor Paragi

The aggregation process of the Amyloidβ (Aβ) peptide is one of the central questions in Alzheimers’s research. Fluorescence-labeled single-molecule detection is a novel technique concerning the early stage investigation of Aβ aggregation, where the labeling dyes are covalently bound to the Aβ monomer. As the influence of the dye on the conformational space of the Aβ monomer can be significant, its effect on the seeding process is an open question. The applied fluorescent molecule continuously switches between an active (ON) and an inactive (OFF) state, where the latter supports an extra rotational restriction at many commercially available dyes. However, only a few theoretical studies simulated the Aβ monomer in the presence of a dye and none of them considered the difference between the ON and the OFF states. Therefore, we examined the impact of a selected fluorescence dye (Alexa 568) on the conformational space of the monomeric Aβ(1–42) peptide in its ON and OFF state by replica exchange molecular dynamic simulations. Investigations on secondary structure elements as well as dye-peptide contact analysis for the monomers are presented. Experimental and theoretical NMR shifts were contrasted to qualify the calculation protocol and theoretical values of the labeled and the non-labeled peptide were also compared. We found that the first five residues have higher helical propensity in the presence of the dye, and electrostatic properties could strongly affect the connection between the dye and the peptide parts.


2019 ◽  
Vol 10 (4) ◽  
pp. 60
Author(s):  
Svenja Kalt ◽  
Lucas Brenner ◽  
Markus Lienkamp

Increasing environmental awareness leads to the necessity for more efficient powertrains in the future. However, the development of new vehicle concepts generates a trend towards ever shorter development cycles. Therefore, new concepts must be tested and validated at an early stage in order to meet the increasing time pressure. This requires the determination of real driving data in fleet tests in order to generate realistic driving cycles, which correspond as closely as possible to the actual driving behavior of the applications use case. Within the scope of this paper, real driving data are analyzed and used to create a representative driving cycle. The resulting driving cycle based on real driving characteristics is then used to investigate the impact of application-based design for powertrains on the design of electric machines, by illustrating the difference between synthetic operating points and real driving data.


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