The Finite Element Analysis of the Deflection of the Crankshaft of Rotary Compressor

The deflection of the crankshaft which transfers the power of motor to the pump of the compressor directly affects the vibration, noises and wear problems in the rotary compressor, therefore, with the requirement of higher reliability, it is important to obtain it exactly in compressor design. Various forces that the crankshaft suffers were calculated by theoretical analysis in the operation process of the compressor. And based on the finite element method (FEM), the deflection of the crankshaft was obtained by simulation in the rotary compressor. And then the measurements were performed concerning the orbit of the top dead centre of the crankshaft with non-contacting displacement sensors in the compressor. In comparison with the tests, the validity of the calculation method was verified. It was found that the results of calculation were good agreement with the tests’. In addition, several factors which affect the deflection of the crankshaft were analyzed with the FEM, and the influences of flange height, shaft diameter, mechanical air gap in the motor, rotor weight on the deflection were found distinctly, which as a primary theoretical basis is provided for the compressor design

A Novel Structure of High Efficiency Rotary Compressor

In recent years, various frequency compressors are developed rapidly and successfully in household air conditioner area. However, it is difficult to make advance progress on compressor performance, noise and reliability. The innovation of structure and technique are indispensable impetus to make a breakthrough. This paper presents a novel structure of high efficiency rotary compressor, which focuses on the connection mode between roller and vane of a compressor. On the one hand, the leakage gap between roller wall and vane tip is eliminated, which upgrades the capacity of compressor. On the other hand, through changing movement type of compressor parts, the mechanical state is meliorated and frictional loss is decreased. Several analysis are studied to validate the rationality of the above amelioration, which include strength and deformation simulation, frictional loss and leakage loss calculation. By comparison with conventional compressor, the performance of the novel compressor is improved obviously. In the end, the results of reliability and durability experiments reveal that they satisfy the national standard

Effective assay technologies fit for large-scale population screening of type 1 diabetes

While worldwide prevention efforts for type 1 diabetes (T1D) are underway to abrogate or slow progression to diabetes, mass screening of islet autoantibodies (IAbs) in the general population is urgently needed. IAbs, the most reliable biomarkers, play an essential role in prediction and clinical diagnosis of T1D. Through laboratory proficiency programs and harmonization efforts, a radio-binding assay (RBA) has been well established as the current ‘gold’ standard assay for all four IAbs. However, in view of the need for large-scale screening in the non-diabetic population, RBA consistently faces two fundamental challenges, cost-efficiency and disease specificity. While all four IAbs are important for disease prediction, the RBA platform, with a separate IAb test format is laborious, inefficient and expensive. Furthermore, the majority of IAb positivity in screening, especially from individuals with single IAb were found to be low risk with low affinity. It is well documented from multiple clinical studies that IAbs with low affinity are low risk with less or no disease relevance. At present, two non-radioactive multiplex assays, a 3-assay ELISA combining three IAbs and a multiplex ECL assay combining all four IAbs, have been successfully used as the primary methods for general population screenings in Germany and the US, respectively. Recently, the TrialNet Pathway to Prevention study has been organizing an IAb workshop which aims to analyze the 5-year T1D predictive values of IAbs. A T1D-specific assay with high efficiency, low cost and requiring low volume of sample will definitely be necessary to benefit general population screening

Relationship between Neutrophil-to-Lymphocyte Ratio and Systemic Lupus Erythematosus: A Metaanalysis

Systemic lupus erythematosus (SLE) is a chronic systematic autoimmune disease. Current methods of diagnosing SLE or evaluating its activity are complex and expensive. Numerous studies have suggested that neutrophil-tolymphocyte ratio (NLR) is closely correlated with the presence of SLE and its activity, suggesting that it may serve as a diagnostic and monitoring indicator for SLE. Therefore, we performed a meta-analysis to systematically assess the association between NLR and SLE. We performed a literature search until 12 April 2019 in the PubMed, Web of Science, and China National Knowledge Infrastructure databases. Cross-sectional studies comparing the NLR of SLE patients versus those of healthy controls, of active versus inactive SLE patients, and of SLE patients with versus without lupus nephritis were considered for inclusion. Mean intergroup NLR differences were estimated using standardized mean differences and their 95% confidence intervals. Study quality was assessed using the Agency for Healthcare Research and Quality instrument for cross-sectional studies. Fourteen studies with 1,781 SLE patients and 1,330 healthy controls were included in this meta-analysis. The pooled results showed that the NLR was significantly higher in SLE patients than in healthy controls, in active SLE patients than in inactive SLE patients, and in SLE patients with lupus nephritis than in those without lupus nephritis. NLR may be an indicator for monitoring disease activity and reflecting renal involvement in SLE patients. Nevertheless, more high-quality studies are warranted to further validate our findings

Fuzzy-Bayesian-network-based Safety Risk Analysis in Railway Passenger Transport

This study presents a fuzzy Bayesian network (FBN) method to analyze the influence on the safety risk of railway passenger transport applying different risk control strategies. Based on the fuzzy probability of the basic event determined by the expert group decision method, the proposed FBN method can reasonably predict the probability of railway passenger safety risk. It is also proven that control the risk in the safety management of railway passenger transport will be the most effective way to reduce the risk probability of the railway passenger transport safety

Study on the Performance of CO2 Two-stage Rotary Compressor in Freezing and Cold Storage Conditions

This paper describes a new type CO2 two-stage rotary compressor for cold storage and freezing of food. A two-stage compression form with an upper cylinder (first-stage) and a lower cylinder (second-stage), unique oil road structures and technical parameters have been used in the rotary compressor to increase the performance. The results indicating that the optimized CO2 two-stage rotary compressor has a significant performance advantage, which the coefficient of performance (COP) increases by 4.4% ~ 6.7%

The Influence of Main Bearing Parameters on The Bearing Wear in Rotary Compressor

The main bearing and sub bearing which support the crankshaft rotation often have wear in the rotary compressor, and the exceptional wear will cause a series of problems which contain the vibration, noises, frictional power rising and reliability reduced. The process of improving the actual exceptional wear problems of bearings is analyzed. And based on the finite element method (FEM), the results of the original and improved bearings are compared with each other; contact stress is chosen to be used to evaluate the wear condition of bearings. Then the influence of height, diameter and clearance of main bearing on the wear of the bearing is analyzed by the accelerated life test and the FEM simulation, and the feasibility of the bearing contact stress to evaluate the wear condition of bearings is further verified, at the same time it provides a theoretical basis for the design of compressor bearing