Influence of Polymer Matrices on the Tensile and Impact Properties of Long Fiber-Reinforced Thermoplastic Composites.

To investigate the influence of polymer matrices on the tensile and impact properties of long fiber-reinforced thermoplastic (LFT) composites, composites of long basalt fiber-reinforced thermoplastic were developed in this work. Two types of polyethylene, namely 8008 and 100S, and two types of polyethylene, namely C4220 and K8303, were chosen as the matrices. The fiber volume fractions were set as 2.8%, 5.9%, 8.1%, and 10.6%. The melt flow index (MFI), crystallinity, tensile properties, impact strength, and fracture morphology of the neat polymers and the corresponding composites were tested. The composites of 8008 showed the highest tensile strength since neat 8008 showed a much higher MFI value and crystallinity. The composites of 8008 and K8303 showed a much higher tensile modulus since the neat thermoplastic showed a higher tensile modulus than the other two composites. The polymer toughness was the factor that determined whether the polymer could be toughened by fibers. Moreover, the interfacial shear strength was calculated and compared with the matrix shear strength, based on which fracture modes of the LFT were predicted. Effective methods were proposed for further improvement of the mechanical properties. The results of this paper were essential for attaining the anticipated properties when designing LFT composites.

[Analysis of the function of diaphragm and its influencing factors in mechanical ventilation patients by using fully automatic trigger twitch tracheal pressure].

OBJECTIVE: To understand the function of diaphragm and analyze the clinical factors affecting the function of diaphragm by measuring twitch tracheal pressure (TwPtr) in patients with mechanical ventilation and in the weaning phase. METHODS: Patients with more than 48 hours of invasive mechanical ventilation admitted to the department of critical care medicine of the First Affiliated Hospital of Guangzhou Medical University from December 2015 to March 2017 were enrolled. After the patient entered the weaning stage, TwPtr of patients was monitored by two-way non repetitive automatic respiratory trigger device, the effects of duration of mechanical ventilation, severe pulmonary infection, sedative application and chronic obstructive pulmonary disease (COPD) on weaning were analyzed. RESULTS: A total of 62 patients were included, of which 45 were male and 17 were female. The average age was (66.8±11.7) years old. Twenty-three cases had severe pneumonia. The absolute value of TwPtr in severe pneumonia group was lower than that in non-severe pneumonia group [cmH2O (1 cmH2O = 0.098 kPa): 10.40±5.81 vs. 14.35±5.22, P = 0.021]. However, there was no significant difference in the duration of mechanical ventilation between the severe pneumonia group and non-severe pneumonia group [days: 26 (17, 43) vs. 15 (11, 36), P = 0.091]. In 62 patients with mechanical ventilation, there was a negative correlation between TwPtr and duration of mechanical ventilation (r = 0.414, P = 0.002), there was also a negative correlation between the duration of mechanical ventilation and TwPtr after the assessment of diaphragm function (r = 0.277, P = 0.039). There was a linear relationship between TwPtr and sedatives (r = 0.220, P = 0.040), but there was no correlation between TwPtr and COPD (r = -0.178, P = 0.166). CONCLUSIONS: For patients in the weaning stage of mechanical ventilation, severe pulmonary infection is one of the factors that affect the diaphragm dysfunction. There is a certain correlation between the diaphragm dysfunction and the use of sedatives.

Adaptive Differential Evolution With Sorting Crossover Rate for Continuous Optimization Problems.

Differential evolution (DE) is one of the best evolutionary algorithms (EAs). The effort of improving its performance has received great research attentions, such as adaptive DE (JADE). Based on the analysis on the aspects that may improve the performance of JADE, we introduce a modified JADE version with sorting crossover rate (CR). In JADE, CR values are generated based on mean value and Gaussian distribution. In the proposed algorithm, a smaller CR value is assigned to individual with better fitness value. Therefore, the components of the individuals, which have better fitness values, can appear in the offspring with higher possibility. In addition, the better offspring generated from last iteration are supposed to have better schemes, hence these schemes are preserved in next offspring generation procedure. This modified version is called as JADE algorithm with sorting CR (JADE_sort). The experiments results with several excellent algorithms show the effectiveness of JADE_sort.