fluid characteristics
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2022 ◽  
Vol 18 (1) ◽  
Author(s):  
Kang Mao ◽  
Guwei Lu ◽  
Yanjiao Li ◽  
Yitian Zang ◽  
Xianghui Zhao ◽  
...  

Abstract Background The fasting and stress associated with road transportation contributes to a lack of energy and a decline in the immune system of beef cattle. Therefore, it is essential for beef cattle to enhance energy reserves before transportation. Creatine pyruvate (CrPyr) is a new multifunctional nutrient that can provide both pyruvate and creatine, which are two intermediate products of energy metabolism. To investigate the effects of transport and rumen-protected (RP)-CrPyr on the blood biochemical parameters and rumen fluid characteristics of beef cattle, twenty male Simmental crossbred cattle (659 ± 16 kg) aged 18 months were randomly allocated to four groups (n = 5) using a 2 × 2 factorial arrangement with two RP-CrPyr supplemental levels (0 or 140 g/d) and two transport treatments (5 min or 12 h): T_CrPyr140, T_CrPyr0, NT_CrPyr140, and NT_CrPyr0. After feeding for 30 days, three cattle per treatment were slaughtered. Results Compared with nontransport, transport decreased the total antioxidant capacity, catalase activity, contents of IgA, interferon γ, interleukin-1β (IL-1β), and IL-6 in serum, and the amounts of total volatile fatty acids (TVFA), acetate, and butyrate in rumen (P < 0.05); increased the serum lipopolysaccharide (LPS) level, contents of rumen LPS and ammonia nitrogen (P < 0.05). RP-CrPyr supplementation decreased the levels of cortisol and LPS in serum and the butyrate concentration in the rumen of beef cattle compared with those in the unsupplemented groups (P < 0.05). RP-CrPyr and transport interaction had a significant effect on the contents of serum tumour necrosis factor-α, IL-6, LPS, ruminal pH, acetate content, and acetate/propionate (P < 0.05). In terms of ruminal bacterial composition, group T_CrPyr0 increased the Prevotella genus abundance compared with group NT_CrPyr0 (P < 0.05), while group T_CrPyr140 increased Firmicutes phylum abundance and decreased Bacteroidetes phylum and genus Prevotella abundance compared with group T_CrPyr0 (P < 0.05). Moreover, Bacteroidetes was positively correlated with serum LPS. Conclusions These results indicated that dietary supplementation with RP-CrPyr might be beneficial to alleviate transport stress by decreasing serum cortisol and LPS levels and promoting the restoration of the rumen natural flora.


Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 67
Author(s):  
Fengming Du ◽  
Changduo Chen ◽  
Kaiguang Zhang

The sliding bearing is an important component in machines. The characteristics of the oil film fluid of the sliding bearing is the key factor affecting lubrication, which will affect the wear and reliability of the sliding bearing. Herein, the lubricating oil of the sliding bearing is studied, the oil film flow model considering the cavitation effect is established, the pressure and temperature distribution of the oil film under different rotational speeds is explored, and its influence on oil film pressure and temperature are analyzed. Furthermore, wear tests are carried out to measure the wear amount of the bearing bush under different rotational speeds, and the influence of the fluid characteristics of the lubricating oil film on bearing wear is explored. The simulation and experimental study in this paper can provide a reference for the design of sliding bearings.


2022 ◽  
Vol 91 ◽  
pp. 94-106
Author(s):  
Yanzhong Wang ◽  
Yaping Zhang ◽  
Fuli Zhang ◽  
Wentao Niu ◽  
Banghua Li ◽  
...  

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Anant Jain ◽  
Anusha Devarajan ◽  
Hussein Assallum ◽  
Ramin Malekan ◽  
Gregg M. Lanier ◽  
...  

Abstract Objectives Pleural effusions appearing within the first 30 postoperative days following coronary artery bypass grafting (CABG) are classified as early and believed to be directly related to the surgery. The characteristics of such effusions are well-described. Orthotopic heart transplantation is also known to be complicated by pleural effusions; however, their characteristics have not been systematically reported. We assessed the features of early postoperative pleural effusions after heart transplantation and compared them to those of early effusions following CABG. Methods We retrospectively collected demographic, clinical, and laboratory data for patients who underwent either orthotopic heart transplantation (study group) or CABG (comparison group) at our institution and whose postoperative course within 30 days was complicated by new or worsening pleural effusion that prompted drainage. Patients subjected to analysis consisted only of those with sufficiently complete laboratory profiles to permit adequate characterization of the nature of their pleural fluid. Results Out of 251 orthotopic heart transplant recipients, seven (2.8%) were found to have sufficiently complete pleural fluid results to be included in the study group. Out of 1,506 patients who underwent CABG, 32 (2.1%) had sufficiently complete pleural fluid results and formed the comparison group. The radiological appearance of pleural effusions in both groups was similar: bilateral in at least half and exclusively moderate to large. Effusions complicating both surgeries were exudative in close to 90% of cases. For those with available leukocyte differential counts, the pleural fluid of the post-orthotopic heart transplantation group was more often neutrophilic (3/5, 60%), whereas the fluid of the post-coronary artery bypass grafting group was more often lymphocytic (22/32, 69%) and tended to be hemorrhagic (median RBC count 33,000 cells/µL vs. 10,000 cells/µL). None of the comparisons of pleural fluid characteristics between the two groups reached statistical significance. Conclusions This small, descriptive study is the first to systematically report the fluid characteristics of pleural effusions complicating orthotopic heart transplantation within the first 30 postoperative days and to compare this group to those who developed effusions after CABG. Our findings revealed both similarities and differences in the pleural fluid characteristics between these two types of patients.


2021 ◽  
pp. 004051752110395
Author(s):  
Xinlei Huang ◽  
Lee Michael Clemon ◽  
Mohammad Saidul Islam ◽  
Suvash C. Saha

As part of the propulsion system, the fluid dynamic features of the main nozzle can immediately affect the stability and efficiency of an air-jet loom. This study aims to optimize the fluid characteristics in the main nozzle of an air-jet loom. To investigate ways of weakening the effect of airflow congestion and backflow phenomenon occurring in the sudden expansion region, the computational fluid dynamics method is employed. Three-dimensional turbulence flow models for a regular main nozzle and 12 prototypes with different nozzle core tip geometry are built, simulated, and analyzed to get the optimum performance. Furthermore, a set of modified equations that consider the direction of airflow are proposed for better estimation of the friction force applied by the nozzle. The result shows that the nozzle core tip's geometry has a significant influence on the internal airflow, affecting the acceleration tube airflow velocity, turbulence intensity, and backflow strength of the sudden expansion region, and other critical fluid characteristics as well. Several proposed models have succeeded in reducing the backflow and outperforming the original design in many different aspects. Models A-60 and C-P, in particular, manage to increase the propulsion force by 37.6% and 20.2% in the acceleration tube while reducing the maximum backflow by 57.1% and 52.2%, respectively. These simulation results can provide invaluable information for the future optimization of the main nozzle.


2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Lunliang Duan ◽  
Meiling Fan ◽  
Duoyin Wang ◽  
Caixia Meng ◽  
Lei Xing

To investigate the wave- and current-induced seabed response near a fully buried subsea pipeline, a two-dimensional coupled model for fluid-seabed-pipeline interaction (FSPI-2D) is developed within the framework of COMSOL multiphysics. Different from previous studies, both the wave-current interaction and the nonlinear pipeline-soil contacts are considered in the present model. In this paper, Biot’s consolidation mode is used to govern the fluid-induced seabed response, and combined Reynolds averaged Navier–Stokes (RANS) equation with the k-ε turbulence model is employed to simulate the fluid propagation. Meanwhile, the pipeline is treated as a linear elasticity. Firstly, the effectiveness of the new model is verified by laboratory experiments from previous reports. Then, the numerical model is employed to examine the effects of nonlinear pipeline-seabed contacts and fluid characteristics on the seabed response around the structure. Finally, the momentary liquefaction near the fully buried pipeline is studied based on the 2D coupled model.


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