scholarly journals Innovative Controllable Torsional Damper Based on Vacuum Packed Particles

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4356
Author(s):  
Dominik Rodak ◽  
Robert Zalewski
Keyword(s):  
Granular Materials ◽  
Solid Body ◽  
Rheological Model ◽  
Laboratory Tests ◽  
Hysteretic Behavior ◽  
Initial Model ◽  
Nonlinear Functions ◽  
Model Formulation ◽  
The Real ◽  
Partial Vacuum

In this paper a new concept of a controllable granular damper is presented. The introduced prototype works based on so-called vacuum packed particles (VPPs). Such structures are made of granular materials located in a soft and hermetic encapsulation. As a result of generating a partial vacuum inside the system, the structure starts to behave like a nonclassical solid body. The global physical (mechanical) features of VPPs depend on the level of internal underpressure. The introduced prototype of a controllable torsional damper exhibits various dissipative properties as a function of internal underpressure. The design details of the investigated device are presented. Basic laboratory tests results are discussed. To describe the hysteretic behavior of the device, the Bouc–Wen rheological model has been modified and adopted. Nonlinear functions of underpressure have been introduced to the initial model formulation. The developed Bouc–Wen model has been applied to capture the real response of the VPP torsional damper prototype.

EFFICIENCY OR EFFECTIVENESS

PEDIATRICS ◽  
1975 ◽  
Vol 56 (2) ◽  
pp. 245-245
Author(s):  
R. J. H.
Keyword(s):  
Health Care ◽  
Medical Care ◽  
Laboratory Tests ◽  
Economies Of Scale ◽  
Utilization Review ◽  
The Real ◽  
Real Issue

The problem of rising costs of medical care has been attacked by two general methods: increased efficiency with business-like methods ("economies of scale," "managing the enterprise," etc.), and reducing use of the most expensive services-excessive hospitalization and laboratory tests—by utilization review. The second approach is more likely to be useful but still misses the real issue, i.e., how effective is what we do in medicine. As Drucker says, "It is effectiveness and not efficiency which the service institutions lack. Effectiveness can not be obtained by business-like behavior as the term is understood." If we could only set objectives, then determine how effectively we achieve them and concentrate our efforts in those areas where effectiveness has been demonstrated, we would have less emphasis on efficiency in health care.

Issues in validation of pre-sliding friction models for ultra-high precision positioning

2018 ◽  
Vol 233 (3) ◽  
pp. 997-1006 ◽  
Author(s):  
Ervin Kamenar ◽  
Saša Zelenika
Keyword(s):  
High Precision ◽  
Sliding Friction ◽  
Hysteretic Behavior ◽  
Slip Model ◽  
Precision Positioning ◽  
Positioning Systems ◽  
The Real ◽  
Sliding Motion ◽  
Real Behavior ◽  
Friction Models

Friction is one of the main disturbances in nanometric positioning. Recently, it was shown that ultra-high precision positioning typically happens in the pre-sliding motion regime where friction is characterized by an elasto-plastic nonlinear hysteretic behavior with a marked stochastic variability. With the aim of providing the tools for the development of robust control typologies for ultra-high precision mechatronics devices, different pre-sliding friction models are thus considered in this work. The most relevant ones are hence experimentally validated, as well as compared in terms of the complexity of identifying their characteristic parameters and of simulating the factual dynamic response. It is hence shown that the generalized Maxwell-slip model can account for all the important pre-sliding frictional effects in nanometric positioning applications. A thorough sensitivity analysis of the parameters of the generalized Maxwell-slip model model is therefore performed allowing to establish that three Maxwell-slip blocks are the minimum needed to approximate the behavior of the real precision positioning systems, six blocks allow representing excellently the real behavior, while the slower dynamics, which induces a difficult real-time implementation, with a very limited gain in terms of model accuracy, does not justify the usage of a larger number of elements.

scholarly journals Thermal Ageing of Power Cable Components Through Penetrations

2019 ◽  
Vol 19 (1) ◽  
pp. 36-42
Author(s):  
D. Puiu ◽  
B. Corbescu ◽  
C. Cepisca
Keyword(s):  
Temperature Increase ◽  
Laboratory Tests ◽  
Thermal Ageing ◽  
Power Cable ◽  
Power Cables ◽  
Temperature Influence ◽  
The Real ◽  
Service Conditions

AbstractThe power cables passing through penetration leads to growth of the thermal ageing mechanisms rate. The paper presents the results of the laboratory tests when the real environmental service conditions for penetration are simulated comparison with the result of the thermal computation of the power cables heating and of the temperature influence evaluation of temperature increase of the power cable components on the cable lifetime. For this particular case, a power cable with PVC insulation, we estimated a lifetime decrease about 20 years referring to lifetime (30÷40 years) for location in air.

scholarly journals Investigation on application of a typical mortar for clinker in prefabricated façade panels - test’s results

2018 ◽  
Vol 174 ◽  
pp. 01030
Author(s):  
Marta Kałuża ◽  
Jacek Hulimka ◽  
Jan Kubica ◽  
Kamil Kozdroń
Keyword(s):  
Water Content ◽  
Working Conditions ◽  
Laboratory Tests ◽  
Strength Properties ◽  
The Real ◽  
Interior Spaces ◽  
Ceramic Components ◽  
Material Tests

In the last period, openwork facades have become very fashionable and commonly used in modern public buildings. They are characterised by an outstanding design and proper lighting of the interior spaces, while providing lightweight solution of the façade. The typical erecting method of an openwork façade - often made of ceramic components - is in-situ bricklaying using specific mortar dedicated to clinker elements. Unfortunately, ensuring proper executive conditions and preparation of the ceramic elements is not always possible. Hence, together with the development of architectural requirements, there has appeared a natural need to create prefabricated elements, which reflect the real bricklaying wall and ensure the safety of the solution. The paper presents a laboratory study on untypical application of a mortar for clinker, used to prefabrication of an elevation panel. The tests of mortar and solution of openwork prefabricated panel made using this mortar and special-shaped clinker components are presented and discussed. The material tests include determination of the strength properties of three types of mortar mixture, differing of each other by water content. The second part of this paper presents the laboratory tests of prefabricated panels, made using previously tested mortars, supported and loaded similar to the real working conditions.

scholarly journals A Novel Approach to the Analysis of Under Sleeper Pads (USP) Applied in the Ballasted Track Structures

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2438 ◽  
Author(s):  
Artur Zbiciak ◽  
Cezary Kraśkiewicz ◽  
Anna Al Sabouni-Zawadzka ◽  
Jan Pełczyński ◽  
Sławomir Dudziak
Keyword(s):  
Finite Element ◽  
Dynamic Characteristics ◽  
Mechanical Model ◽  
Rheological Model ◽  
Laboratory Tests ◽  
Vibration Isolation ◽  
Special Focus ◽  
Vibration Isolators ◽  
Novel Approach ◽  
Ballasted Track

The present paper is dedicated to the analysis of under sleeper pads (USP), which are resilient elements used in ballasted track systems as vibration isolators. Four types of USP are considered. The authors present the results of laboratory tests, which are then used as input values for the finite element (FE) and mechanical model of the structure. A special focus is put on the description of an original four-degree-of-freedom (4DoF) mechanical model of the system that includes a fractional rheological model of USP. Using the proposed approaches, the dynamic characteristics of under sleeper pads are determined, and conclusions on vibration isolation effectiveness are drawn.

Robust Multiscale Deformable Registration of 3D Ultrasound Images

2003 ◽  
Vol 03 (04) ◽  
pp. 547-565 ◽  
Author(s):  
Ioannis Pratikakis ◽  
Christian Barillot ◽  
Pierre Hellier ◽  
Etienne Memin
Keyword(s):  
3D Ultrasound ◽  
Scale Space ◽  
Ultrasound Images ◽  
Initial Model ◽  
Model Formulation ◽  
Registration Method ◽  
Registration Process ◽  
Coarse To Fine ◽  
Linear Scale Space ◽  
Minimization Scheme

In this paper, we embed the minimization scheme of an automatic 3D non-rigid registration method in a multiscale framework. The initial model formulation was expressed as a robust multiresolution and multigrid minimization scheme. At the finest level of the multiresolution pyramid, we introduce a focusing strategy from coarse-to-fine scales which leads to an improvement in the accuracy of the registration process. A focusing strategy has been tested for a linear and a non-linear scale-space. Results on real 3D ultrasound images are discussed.

Robust deep learning seismic inversion with a priori initial model constraint

2021 ◽  
Author(s):  
Jian Zhang ◽  
Jingye Li ◽  
Xiaohong Chen ◽  
Yuanqiang Li ◽  
Guangtan Huang ◽  
...  
Keyword(s):  
Deep Learning ◽  
Seismic Data ◽  
A Priori ◽  
Seismic Inversion ◽  
Training Dataset ◽  
Initial Model ◽  
Data Set ◽  
The Real ◽  
Model Constraint ◽  
Trained Network

Summary Seismic inversion is one of the most commonly used methods in the oil and gas industry for reservoir characterization from observed seismic data. Deep learning (DL) is emerging as a data-driven approach that can effectively solve the inverse problem. However, existing deep learning-based methods for seismic inversion utilize only seismic data as input, which often leads to poor stability of the inversion results. Besides, it has always been challenging to train a robust network since the real survey has limited labeled data pairs. To partially overcome these issues, we develop a neural network framework with a priori initial model constraint to perform seismic inversion. Our network uses two parts as one input for training. One is the seismic data, and the other is the subsurface background model. The labels for each input are the actual model. The proposed method is performed by log-to-log strategy. The training dataset is firstly generated based on forward modeling. The network is then pre-trained using the synthetic training dataset, which is further validated using synthetic data that has not been used in the training step. After obtaining the pre-trained network, we introduce the transfer learning strategy to fine-tune the pre-trained network using labeled data pairs from a real survey to acquire better inversion results in the real survey. The validity of the proposed framework is demonstrated using synthetic 2D data including both post-stack and pre-stack examples, as well as a real 3D post-stack seismic data set from the western Canadian sedimentary basin.

scholarly journals EFFECT OF WASTE MATERIALS ON CALIFORNIA BEARING RATIO FOR GRANULAR BASE

2021 ◽  
Vol 25 (Special) ◽  
pp. 3-149-3-156
Author(s):  
Jleel H. Rasheed ◽  
◽  
Zainab A. Alkaissi ◽  
Hanan A. Hassan ◽  
◽  
...  
Keyword(s):  
Compressive Strength ◽  
Granular Materials ◽  
Treatment Period ◽  
Laboratory Tests ◽  
Base Material ◽  
Base Layer ◽  
Waste Materials ◽  
Foundry Sand ◽  
Cbr Test ◽  
Granular Base

It is known that paving is a system with multiple layers and the strength of each layer is reflected on the entire pavement. Two kinds of materials are used as the base layer, and the materials are divided into ordinary traditional granular materials and recycled materials such as foundry sand. This paper presents the results of laboratory tests in the laboratory and discusses the effect of each of the materials and foundry sand and its effect as a stabilizer on the strength of the substrate and as a stabilizer. Also, a comparison is made between the changes that occur in the base layer Cast sand treated and compared with untreated. A mixture of foundry sand with graded natural aggregate according to certain sizes is used as a stabilizer in proportions (5, 10 and 15) %. The treated and untreated base layer is compared in terms of strength. The base layer material is a traditional base material taken from the Nabaie quarry. Samples are made of three replicates of each possible group. Samples were prepared and subjected to a compressive strength CBR test. The obtained results indicate an increase in the resistance of the base material when using FS at a rate of (5%) with a treatment period of 4 days, while a ratio of 10% gave the highest resistance in a treatment period of 14 days, and these ratios gave more resistance than the untreated samples without the additive.

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