A New Approach to Fit Bearing Performance to Advanced Gas Engine Technology

2002 ◽  
Author(s):  
Thomas Rumpf ◽  
Johannes Humer ◽  
Elisabeth Schneiderbauer ◽  
Michael Putz
Keyword(s):  
Life Time ◽  
Test Methods ◽  
Hydrodynamic Performance ◽  
Test Procedures ◽  
Gas Engine ◽  
Simulation Tools ◽  
Bearing Materials ◽  
Engine Components ◽  
Long Term Behavior

Gas engines get an increasing market share compared to four stroke engines, especially in the field of energy systems. Under these special firing conditions engine components are stressed differently than in traditional diesel engines. This particularly is the case for bearings. In order to supplement the knowledge base for bearing performance under these aggravated conditions, special test methods have been developed to find out reasons for premature bearing failure characteristics. In combination with experience from the long term behavior of different bearing types in different gas engine applications, this data allows the development of improved bearing materials as well as bearing designs. Using this knowledge in combination with advanced simulation tools, a bearing supplier can offer assistance to select adequate bearing designs, give a life time prediction and in case of unexpected phenomena, redesign recommendations. The paper presents reasons and influences for life time limitations as well as different risk factors for available bearing types and situations. Based on field experience and data from the advanced bearing test procedures, values for bearing performance are given. Data for hydrodynamic performance, tribological properties and emergency running behavior, cavitation resistance, wear resistance and last, but not least corrosion resistance against active sulfur and halogens will be given for traditional and newly developed bearing materials. A short view into the future will finish the presentation.

The generalized regularities of damageability and integrity in estimations of the endurance in conditions of variability of loading regimes

2019 ◽  
Vol 85 (9) ◽  
pp. 61-65
Author(s):  
N. A. Makhutov
Keyword(s):  
Life Time ◽  
Cyclic Strength ◽  
Laboratory Diagnostics ◽  
Methodological Issues ◽  
Break Points ◽  
Number Of Cycles ◽  
Cyclic Damage ◽  
Damage Summation ◽  
Temperature Factors

We consider and analyze general methodological issues regarding the strength and endurance (life-time) of the materials and structure elements under a combined effect of various force, deformation and temperature factors. The Journal "Zavodskaya laboratoriya. Diagnostika materialov" (Industrial laboratory. Diagnostics of materials) has launched systematic publications on this problematic since 2018. For many decades, domestic and foreign laboratory studies have gleaned to a traditional methodology for obtaining initial curves of the long-term and cyclic strength that related the breaking stresses with time or number of cycles. These curves, with the characteristic sections and break points, separating the areas of elastic and inelastic (plastic strain or creep strain) strain, are used in analysis of long-term and cyclic damage. Using the elementary linear law of damage summation, it is possible to calculate at a first approximation the strength and endurance under varying conditions of loading. Stepping up the requirements to the accuracy of calculations necessitates a transition from force fracture criteria (at stresses a) to deformation criteria (in elastic and inelastic deformations e). Thus, it becomes possible to construct and use a unified expression for the curve of the long-term cyclic fracture (taking into account the temporal x and cyclic N factors) and a long-term cyclic damage. With such approach it is possible to remain the linear law of damage summation though those damages are obviously nonlinear. The goal of the study is to continue and support the discussion of the most complex problems of a comprehensive assessment of the strength, resource, survivability and safety of high-risk engineering equipment within the journal pages.

A Novel Potentiometric PVC-membrane Cysteamine-Selective Electrode Based on Cysteamine-Phosphomolybdate Ion-Pair

2020 ◽  
Vol 16 (2) ◽  
pp. 168-175 ◽  
Author(s):  
Merve Tumur ◽  
Gulsah Saydan Kanberoglu ◽  
Fatih Coldur
Keyword(s):  
Analytical Methods ◽  
Pharmaceutical Preparations ◽  
Life Time ◽  
Ion Pair ◽  
Pharmaceutical Formulation ◽  
Pvc Membrane ◽  
Selective Electrode ◽  
Potentiometric Response ◽  
Drug Quality Control

Background: Cysteamine is used as an orphan drug in the treatment of cystinosis to prevent long-term cystine accumulation in lysosomes. Dosing in cysteamine treatment is extremely important and overdose may cause some side effects. Up to now, various analytical methods have been used for cysteamine determination. Many of these methods require sophisticated instruments, expert operators, time-consuming measurement procedures and manipulation steps, expensive supplies and long analysis time. Aims and Objective: The present study deals with the development of a potentiometric PVC-membrane cysteamine-selective electrode based on an ion-pair of cysteamine and its application in a pharmaceutical formulation. Methods: Cysteamine (Cys)-Phosphomolybdate (PM) ion-pair was synthesized by mixing the equal volumes of 10-2 M Cysteamine HCl and sodium phosphomolybdate aqueous solutions. The obtained precipitate was used as ionophore in the structure of PVC-membrane. Results and Discussion: The electrode exhibited a linear response in the concentration range of 1.0×10- 1-1.0×10-5 M cysteamine with a slope of 51,7 mV per decade and detection limit of 1.0×10-5 M. The potentiometric response of the electrode was very rapid (5 s), adequately repeatable, stable and selective. pH working range and life-time of the electrode were also determined as 3.0-7.0 and 25 days, respectively. Conclusion: A PVC-membrane cysteamine selective electrode was easily prepared. Cysteamine determination in a pharmaceutical formulation was performed. Analysis results indicated that it can be successfully used in drug quality control laboratories for routine analysis of cysteamine in pharmaceutical preparations alternative to more sophisticated, expensive and time-consuming analytical methods.

Effects of acute seizures on cell proliferation, synaptic plasticity and long-term behavior in adult zebrafish

2021 ◽  
Vol 1756 ◽  
pp. 147334
Author(s):  
Charles Budaszewski Pinto ◽  
Natividade de Sá Couto-Pereira ◽  
Felipe Kawa Odorcyk ◽  
Kamila Cagliari Zenki ◽  
Carla Dalmaz ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Synaptic Plasticity ◽  
Adult Zebrafish ◽  
Acute Seizures ◽  
Long Term Behavior

Using Generalized Cell Mapping to Approximate Invariant Measures on Compact Manifolds

1997 ◽  
Vol 07 (11) ◽  
pp. 2487-2499 ◽  
Author(s):  
Rabbijah Guder ◽  
Edwin Kreuzer
Keyword(s):  
Dynamical Systems ◽  
Invariant Measures ◽  
Nonlinear Dynamical Systems ◽  
Powerful Method ◽  
Cell Mapping ◽  
Generalized Cell Mapping ◽  
Nonlinear Dynamical ◽  
Long Term Behavior ◽  
Mapping Theory

In order to predict the long term behavior of nonlinear dynamical systems the generalized cell mapping is an efficient and powerful method for numerical analysis. For this reason it is of interest to know under what circumstances dynamical quantities of the generalized cell mapping (like persistent groups, stationary densities, …) reflect the dynamics of the system (attractors, invariant measures, …). In this article we develop such connections between the generalized cell mapping theory and the theory of nonlinear dynamical systems. We prove that the generalized cell mapping is a discretization of the Frobenius–Perron operator. By applying the results obtained for the Frobenius–Perron operator to the generalized cell mapping we outline for some classes of transformations that the stationary densities of the generalized cell mapping converges to an invariant measure of the system. Furthermore, we discuss what kind of measures and attractors can be approximated by this method.

Long-Term Behavior of Wood-Concrete Composite Floor/Deck Systems with Shear Key Connection Detail

2007 ◽  
Vol 133 (9) ◽  
pp. 1307-1315 ◽  
Author(s):  
M. Fragiacomo ◽  
R. M. Gutkowski ◽  
J. Balogh ◽  
R. S. Fast
Keyword(s):  
Shear Key ◽  
Long Term Behavior

Attractors for multi-valued lattice dynamical systems with nonlinear diffusion terms

2021 ◽  
Author(s):  
Panpan Zhang ◽  
Anhui Gu
Keyword(s):  
Dynamical Systems ◽  
Nonlinear Diffusion ◽  
Upper Semicontinuity ◽  
Growth Conditions ◽  
Pullback Attractor ◽  
Random Lattice ◽  
Lipschitz Continuous ◽  
Lattice Dynamical Systems ◽  
Long Term Behavior

This paper is devoted to the long-term behavior of nonautonomous random lattice dynamical systems with nonlinear diffusion terms. The nonlinear drift and diffusion terms are not expected to be Lipschitz continuous but satisfy the continuity and growth conditions. We first prove the existence of solutions, and establish the existence of a multi-valued nonautonomous cocycle. We then show the existence and uniqueness of pullback attractors parameterized by sample parameters. Finally, we establish the measurability of this pullback attractor by the method based on the weak upper semicontinuity of the solutions.

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