scholarly journals Modeling of Curvilinear Steel Rod Structures Based on Minimal Surfaces

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6826
Author(s):  
Jolanta Dzwierzynska ◽  
Igor Labuda
Keyword(s):  
Minimal Surfaces ◽  
Single Layer ◽  
Optimization Criterion ◽  
The Other ◽  
Base Surface ◽  
Practical Applications ◽  
Physical Tests ◽  
Rod Structures ◽  
Roof Function ◽  
Initial Base

The article deals with shaping effective curvilinear steel rod roof structures using genetic algorithms by implementing them for the analysis of various case studies in order to find new and efficient structures with positive characteristics. The structures considered in this article are created on the basis of the Enneper surface and minimal surfaces stretched on four arcs. On the Enneper surface, a single layer grid is used, while on the other surfaces, two-layer ones. The Enneper form structure with four supports and the division into an even number of parts along the perimeter of the covered place proved to be the most efficient, and the research showed that small modifications of the initial base surface in order to adapt the structure to the roof function did not significantly affect its effectiveness. However, the analysis and comparison of single and double-shell rod structures based on minimal surfaces stretched on four arcs have shown that a single-shell structure is much more effective than a double one. The paper considers the theoretical aspects of shaping effective structures, taking their masses as the optimization criterion. The optimization helped to choose the best solutions due to structures’ shapes and topologies. However, the obtained, optimized results can find practical applications after conducting physical tests.

Some Practical Applications of Rubber Dampers for the Suppression of Torsional Vibrations in Engine Systems

1945 ◽  
Vol 153 (1) ◽  
pp. 61-82 ◽  
Author(s):  
R. W. Zdanowich ◽  
J. E. Moyal
Keyword(s):  
Tuning Curve ◽  
The Other ◽  
Mass System ◽  
Practical Applications ◽  
System Method ◽  
Practical Support ◽  
Physical Tests ◽  
Curve Method ◽  
Damper Design ◽  
Engine Systems

The method of rubber damper design outlined in this paper has been developed owing to the breakdown on a number of occasions of the two-mass system method hitherto widely used. This new method, which is based on the study of the behaviour of the engine as a whole in conjunction with the damper, splits up the functioning of a damper into two parts, one conveniently called the detuning effect, and the other, the absorption effect. The first relies on the powerful tuning curve method, already described in the Proceedings, and the other is based on numerous painstaking trials and physical tests on rubber samples and on full-scale dampers. The method outlined shows that there is no rigid relationship between the frequencies of the engine and damper, and that the free end of the engine crankshaft is not the only place where a successful damper can be fitted. In addition to giving some particulars about physical and other properties of rubber, it also shows how to calculate the heat dissipated by dampers. Practical support for the theory is provided by accounts of vibration trials on three widely different types of engines with dampers fitted to them. In all cases, comparison of calculated and experimental amplitudes is given. The good agreement between the two cannot escape attention and shows that the method outlined can be used with confidence.

scholarly journals Radiation-Induced Asymmetric Grafting of Different Monomers into Base Films to Prepare Novel Bipolar Membranes

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2028
Author(s):  
Shin-ichi Sawada ◽  
Yasunari Maekawa
Keyword(s):  
Acrylic Acid ◽  
Anion Exchange ◽  
Graft Polymerization ◽  
The Other ◽  
Practical Applications ◽  
Bipolar Membranes ◽  
Graft Polymers ◽  
Grafting Reactions ◽  
Radiation Induced

We prepared novel bipolar membranes (BPMs) consisting of cation and anion exchange layers (CEL and AEL) using radiation-induced asymmetric graft polymerization (RIAGP). In this technique, graft polymers containing cation and anion exchange groups were introduced into a base film from each side. To create a clear CEL/AEL boundary, grafting reactions were performed from each surface side using two graft monomer solutions, which are immiscible in each other. Sodium p-styrenesulfonate (SSS) and acrylic acid (AA) in water were co-grafted from one side of the base ethylene-co-tetrafluoroethylene film, and chloromethyl styrene (CMS) in xylene was simultaneously grafted from the other side, and then the CMS units were quaternized to afford a BPM. The distinct SSS + AA- and CMS-grafted layers were formed owing to the immiscibility of hydrophilic SSS + AA and hydrophobic CMS monomer solutions. This is the first BPM with a clear CEL/AEL boundary prepared by RIAGP. However, in this BPM, the CEL was considerably thinner than the AEL, which may be a problem in practical applications. Then, by using different starting times of the first SSS+AA and second CMS grafting reactions, the CEL and AEL thicknesses was found to be controlled in RIAGP.

scholarly journals Analysis of multilayer electro-active tubes under different constraints

2018 ◽  
Vol 30 (1) ◽  
pp. 45-62 ◽  
Author(s):  
Eliana Bortot
Keyword(s):  
Single Layer ◽  
Layer Model ◽  
Active Materials ◽  
Practical Applications ◽  
Geometrical Properties ◽  
Active Membrane ◽  
Electromechanical Transduction ◽  
Compliant Behavior ◽  
Coating Layers ◽  
Soft Dielectrics

Dielectric elastomers are an emerging class of highly deformable electro-active materials employed for electromechanical transduction technology. For practical applications, the design of such transducers requires a model accounting for insulation of the active membrane, non-perfectly compliant behavior of the electrodes, or interaction of the transducer with a soft actuated body. To this end, a three-layer model, in which the active membrane is embedded between two soft passive layers, can be formulated. In this article, the theory of non-linear electro-elasticity for heterogeneous soft dielectrics is used to investigate the electromechanical response of multilayer electro-active tubes—formed either by the active membrane only ( single-layer tube) or by the coated active membrane ( multilayer tube). Numerical results showing the influence of the mechanical and the geometrical properties of the soft coating layers on the electromechanical response of the active membrane are presented for different constraint conditions.

Total Productive Maintenance: Competing or Complementary to other Initiatives?

2013 ◽  
Vol 315 ◽  
pp. 472-476
Author(s):  
Adnan Hj. Bakri ◽  
Abdul Rahman Abdul Rahim ◽  
Noordin Mohd Yusof
Keyword(s):  
Large Scale ◽  
Manufacturing Industry ◽  
Short Review ◽  
The Other ◽  
Total Quality ◽  
Total Productive Maintenance ◽  
Quality Initiatives ◽  
Practical Applications ◽  
Manufacturing Organization

The objective of this short review paper is to examine the practical applications of Total Productive Maintenance (TPM) in the manufacturing industry. In this short review, an attempt was made to critically discuss the previous literatures related to TPM with the other established quality initiatives in the manufacturing, such as Total Quality Management (TQM) and Just-In-Time practice (JIT). This literature review-based research revealed an important research gaps related to TPM. The significance role of TPM as an important complementary to either TQM or JIT initiative is observed not been well addressed in the available literatures. Most of the researches available investigate these initiatives separately, focuses on the other element rather than addressing on the significant role of TPM as one of the main thrust. The separate implementation of such quality initiatives in the manufacturing organization means the requirement of large scale human, financial and technical resources as well the associated problems of running competing project in the company. The outcomes from this review justify the needs of further research in the area of TPM integration with other available initiatives, to further enhance its methodology aimed at solidifying its philosophy towards more realistic practical applications.

Effect of Specimen Geometry on the Predicted Mechanical Behavior of Polyethylene Pipe Material

2014 ◽  
Author(s):  
Tarek M. A. A. El-Bagory ◽  
Tawfeeq A. R. Alkanhal ◽  
Maher Y. A. Younan
Keyword(s):  
Mechanical Behavior ◽  
Longitudinal Direction ◽  
Primary Objective ◽  
The Other ◽  
Pipe Material ◽  
Ring Specimen ◽  
Design Data ◽  
Practical Applications ◽  
Other Hand ◽  
Gauge Section

The primary objective of the present paper is to depict the mechanical behavior of high density polyethylene, (HDPE), pipes under different loading conditions with different specimen geometries to provide the designer with reliable design data relevant to practical applications. Therefore, it is necessary to study the effect of strain rate, ring configuration, and grip or fixture type on the mechanical behavior of dumb-bell-shaped, (DBS), and ring specimens made from HDPE pipe material. DBS and ring specimens are cut from the pipe in longitudinally, and circumferential (transverse) direction respectively. On the other hand, the ring specimen configuration is classified into two types; full ring, (FR), and notched ring, (NR) (equal double notch from two sides of notched ring specimen) specimens according to ASTM D 2290-12 standard. Tensile tests are conducted on specimens cut out from the pipe with thickness 10 mm at different crosshead speeds (10–1000 mm/min), and ambient temperature, Ta = 20 °C to investigate the mechanical properties of DBS, and ring specimens. In the case of test specimens taken from longitudinal direction from the pipe a necking phenomenon before failure appears at different locations along the gauge section. On the other hand, the fracture of NR specimens occurs at one notched side. The results demonstrated that the NR specimen has higher yield stress than DBS, and FR specimens at all crosshead speeds. The present experimental work reveals that the crosshead speed has a significant effect on the mechanical behavior of both DBS, and ring specimens. The fixture type plays an important role in the mechanical behavior for both FR and NR specimens at all crosshead speeds.

Zero Knowledge Proofs

2018 ◽  
pp. 111-123 ◽  
Author(s):  
Kannan Balasubramanian ◽  
Mala K.
Keyword(s):  
Real World ◽  
The Other ◽  
Interactive Proof ◽  
Zero Knowledge ◽  
Practical Applications ◽  
Proof Of Knowledge ◽  
Real World Applications ◽  
Special Case ◽  
Zero Knowledge Proof

Zero knowledge protocols provide a way of proving that a statement is true without revealing anything other than the correctness of the claim. Zero knowledge protocols have practical applications in cryptography and are used in many applications. While some applications only exist on a specification level, a direction of research has produced real-world applications. Zero knowledge protocols, also referred to as zero knowledge proofs, are a type of protocol in which one party, called the prover, tries to convince the other party, called the verifier, that a given statement is true. Sometimes the statement is that the prover possesses a particular piece of information. This is a special case of zero knowledge protocol called a zero-knowledge proof of knowledge. Formally, a zero-knowledge proof is a type of interactive proof.

Effects of Adjacent Ground Treatment on Site Seismic Response

2011 ◽  
Vol 90-93 ◽  
pp. 1576-1580
Author(s):  
Gang Ge ◽  
Jian Min Liu
Keyword(s):  
Ground Motion ◽  
Single Layer ◽  
Soil Improvement ◽  
Soil Reinforcement ◽  
The Other ◽  
Acceleration Response ◽  
Horizontal Acceleration ◽  
Ground Treatment ◽  
Single Block ◽  
Adjacent Soil

The effect of adjacent soil improvement on ground motion is studied using finite element method, when seismic wave is introduced from the single layer on bedrock. The influence of ground motion on soil reinforcement is analyzed; the impacts of the reinforcement zone width, depth, elastic modulus, and the soil improvement interval on response of the ground motion are also investigated. Study shows: for the same site, when the distance between two adjacent foundation consolidation interval is less than 3 to 4 times the width of the reinforcement area, the interaction acceleration response amplitude of various points on the surface of the two adjacent reinforcement area increased significantly than the single block; within the interval , increasing one of the two adjacent foundation’s width, depth, and the other foundation surface, the horizontal acceleration response will Subsequently enlarged; when the interval between the reinforcement area is greater than the range, this effect is negligible.

Characterization of Single- and Multiple-Layer Films by X-Ray Reflectometry

1991 ◽  
Vol 35 (A) ◽  
pp. 137-142 ◽  
Author(s):  
T. C. Huang ◽  
W. Parrish
Keyword(s):  
Experimental Data ◽  
Thin Films ◽  
High Resolution ◽  
Single Layer ◽  
The Other ◽  
X Ray ◽  
Buried Interfaces ◽  
Multiple Layer ◽  
Reflectivity Data

AbstractPrecision X-ray reflectivity data were obtained with a high-resolution reflectometer equipped with a rotating anode X-ray source and Ge 220 channel monochromators (one placed before and the other after the specimen). The surfaces and buried interfaces of thin films were characterized by ieast-squares refinement of experimental data. Values of thickness, density, and/or roughness of Pt “single-layer” and Pt/Co based multiple-layer films were determined.

scholarly journals The limits of distribution-free conditional predictive inference

2020 ◽  
Author(s):  
Rina Foygel Barber ◽  
Emmanuel J Candès ◽  
Aaditya Ramdas ◽  
Ryan J Tibshirani
Keyword(s):  
The Other ◽  
Conditional Inference ◽  
Predictive Inference ◽  
Distribution Free ◽  
Conformal Prediction ◽  
Underlying Distribution ◽  
Practical Applications ◽  
Other Hand ◽  
Test Points ◽  
Exact Conditional Inference

Abstract We consider the problem of distribution-free predictive inference, with the goal of producing predictive coverage guarantees that hold conditionally rather than marginally. Existing methods such as conformal prediction offer marginal coverage guarantees, where predictive coverage holds on average over all possible test points, but this is not sufficient for many practical applications where we would like to know that our predictions are valid for a given individual, not merely on average over a population. On the other hand, exact conditional inference guarantees are known to be impossible without imposing assumptions on the underlying distribution. In this work, we aim to explore the space in between these two and examine what types of relaxations of the conditional coverage property would alleviate some of the practical concerns with marginal coverage guarantees while still being possible to achieve in a distribution-free setting.

Teaching Geography to High School Students with Academic Deficits: Effects of a Computerized Map Tutorial

1988 ◽  
Vol 11 (4) ◽  
pp. 371-379 ◽  
Author(s):  
Steven V. Horton ◽  
Thomas C. Lovitt ◽  
Tim Slocum
Keyword(s):  
Learning Disabilities ◽  
High School Students ◽  
Learning Disabled ◽  
Ninth Grade ◽  
The Other ◽  
Students With Learning Disabilities ◽  
School Students ◽  
Practical Applications ◽  
Significant Difference ◽  
Academic Deficits

This research investigated the effectiveness of two treatments designed to teach the locations of 28 major cities in Asia to students identified as learning disabled and remedial enrolled in a ninth-grade world geography class. In one treatment, students were presented the locations of 14 cities by completing a computerized map tutorial. In the other intervention, students were asked to learn the locations of 14 different cities by referencing an atlas and transcribing their findings to a work map. Results indicated that the computerized map tutorial produced significantly higher performance than the atlas condition for students with learning disabilities and remedial pupils. Within treatments, no significant difference was noted in the performance of the two groups. Several practical applications of computerized graphics for students with academic deficits are discussed.

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