The Intrauterine fetal development process is complicated and affected by many regulating factors such as maternal nutritional status, transcription factors and adipokines. Adipokines are kinds of active substances secreted by adipose tissue, including more than 50 kinds of molecules. To explore the correlation between calf birth weights and adipokines including adiponectin, leptin, visfatin, and IGF-1 in cows venous and venous cord blood. Fifty-four healthy multiparous Chinese Holstein cows were used; in which, cows with a calf weight less than 40 kg were included in group A (n=9); those with a calf weight between 40 kg~45 kg were included in group B (n=25) and ≥45 kg were included in group C (n=20), venous blood and cord venous blood was collected. An ELISA kit was used to evaluate the concentration of adiponectin, leptin, visfatin, and IGF-1, correlations between index-index and index-calf birth weight were analysed. In both cows venous and cord venous blood, adiponectin, leptin, visfatin, and IGF-1 levels were significantly correlated with each other (p<0.01), and levels of these adipokines in venous blood were significantly higher than cord venous blood (p<0.01). Adiponectin, leptin, visfatin, and IGF-1 in venous cord blood were positively correlated with calf birth weights, and significantly correlated with calf birth weights respectively (p<0.01). Our study showed that adiponectin, leptin, and IGF-1 were found in venous blood and cord venous blood, and adiponectin, leptin, and IGF-1 in venous and cord venous blood potentially inter-regulated each other; adiponectin, leptin, and IGF-1 in venous blood were not significantly correlated with calf birth weights, while adiponectin, leptin, visfatin, and IGF-1 in venous cord blood were significantly correlated with calf birth weights, respectively.
The proportional-integral-derivative (PID) controllers have experienced series of structural modifications and improvements. Example of such modifications are set-point weighting and fractional ordering. While the former is to achieve two-degree-of-freedom (2DOF) ability of set-point tracking and disturbance rejection, the latter is to ensure smooth control action. Therefore, this paper reviews various forms of PID controllers and provides a comparative analysis of 2DOF PID and 2DOF fractional order PID (FOPID) controllers. The paper also discusses the conversion of one PID form to another. For the comparative analysis of the various controllers, a class of unstable systems are considered. Simulation result shows that in most cases the conversion from one form to another does not significantly affect the performance of the system. It is also observed that the 2DOF controllers (2DOF PID and 2DOF FOPID) improved significantly the performance of the ordinary PID controllers.
One of the main problems of multivariable cost functions in model predictive control is the choice of weighting factors. Two finite control set model predictive control algorithms, applied to the three-phase active rectifier with an LCL filter, are described in the paper. The investigated algorithms, i.e. PCicuc and PCigicuc, implement multivariable approaches applying line (grid) current, capacitor voltage and converter current. The main problem dealt with in the paper is the choice of optimum values of the cost function weighting factors. The values of the factors calculated using the method proposed in the paper are very close to the values represented by the lowest THDi of the line current. Moreover, simulations verifying the equations used in the prediction of controlled values, i.e. line current, capacitor voltage and converter current, are presented. Both simulation and experimental results are presented to verify effectiveness of the investigated control strategies under change of the load (P = 5 kW and 2.5 kW), during transient states, under unbalanced and balanced line voltage.
Tensile structures in general, achieve their load-carrying capability only after the process of initial form-finding. From the mechanical point of view, this process can be considered as a problem in statics. As cable systems are close siblings of trusses (cables, however, can carry tensile forces only), in our study we refer to equilibrium equation similar to those known from the theory of the latter. In particular, the paper regards designing pre-tensioned cable systems, with a goal to make them kinematically stable and such that the weight of so designed system is lowest possible. Unlike in typical topology optimization problems, our goal is not to optimize the structural layout against a particular applied load. However, our method uses much the same pattern. First, we formulate the variational problem of form-finding and next we describe the corresponding iterative numerical procedure for determining the optimum location of nodes of the cable system mesh. We base our study on the concept of force density which is a ratio of an axial force in cable segment to its length.
en
pl
