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2. Česká zkušenost a sociologická reflexe: poznámky ke knize Pavla Machonina Česká společnost a sociologické poznaní, Praha: ISV nakladatelství 2005, 288 s.

Creator:
Arnason, Johann P.
Format:
print
Type:
model:internalpart and TEXT
Subject:
modernization theory, multiple modernities, Czech sociology - history of, Pavel Machonin, and sociology of knowledge
Language:
Czech
Description:
The article deals with some key arguments in Pavel Machonin's book Czech Society and Sociological Knowledge, but does not review the whole book. Critical comments focus on four themes. Machonin's conception of sociology as a discipline and a tradition does not do full justice to the inherent pluralism of the sociological imagination. It is useful to link sociological debates to the ideological contest between socialism (more particularly Marxism) and liberalism, but this problematic is more complex than Machonin's analyses tend to suggest; that applies, in particular, to the interpretations of freedom and equality as fundamental modern values. Machonin's attempt to reconstruct modernization theory is open to some criticisms, especially with regard to the debate on „multiple modernities." Finally, the concept of state socialism does not help to grasp the complex patterns of modernity that developed under Communist rule.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Finite element back analysis of geostress field in geological body of oil and gas trap

Creator:
Xu, Meng, Yang, Junwei, Jia, Shanpo, and Chen, Zhenlong
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
geostress field, boundary load, finite element method, least square method, and finite element inverse approximation
Language:
English
Description:
The boundary conditions and loading ways of geostress field of oil and gas trap are the difficulties in the numerical simulation and geomechanical analysis. Owing to the limited data of geostress, unclear tectonic movement and complex geological structure, the stress field cannot be solved directly. Boundary load inversion is a very important method to analyze the stress field of rock mass. Based on the measured in-situ stress of S4 member in C41 fault block of Liangjialou oilfield, the boundary loads of the geological body stress field are inversely calculated. Meanwhile, the optimal boundary stress obtained by the inverse modeling is used to study the stress field near the fault. This method can overcome the shortcomings of common back analysis, such as boundary load adjustment method and regression method, and improve the calculation accuracy of stress field. The results show that the inversion method is simple, reliable, accurate and fast. The distribution of stress field can well reflect the in homogeneity of the magnitude and direction of the stress field near the fault. Therefore, this method has a certain application value in boundary load inversion, and the initial stress field distribution of faults provides a precondition for local stability.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

4. Simulation of voltage dip event in fixed-speed wind turbines: fatigue evaluation

Creator:
Veluri, Badrinath, Santos-Martin, David, and Jensen, Henrik Myhre
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
voltage dip, electro-mechanical model, drivetrain, induction generator, rainflow count, and fatigue
Language:
English
Description:
Grid code modifications require the in service fixed speed wind turbines to ride-through grid faults. Voltage dips due to electrical grid faults generate transients of the generator electromagnetic torque. These transients result in significant stresses and vibrations affecting the fatigue life of the components. An electro-mechanical model was built to simulate the grid faults that excite the asynchronous generator with poorly damped stator flux oscillations. These oscillations cause transients of the generator electromagnetic torque. This article focuses in estimating the resulting significant stresses transients affecting the fatigue life of drivetrain system due to voltage dips. A rainflow cycle counting method was developed to evaluate the fatigue life of the mechanical system. The methodology analyses the stress history and estimates the mean and amplitudes of the counted cycles, and time of duration to calculate the accumulated damage occurred during the voltage dip event. and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public