Experimental Investigation Into the Relationship Between the Roughness Height in Use With Nikuradse or Colebrook Roughness Functions and the Internal Wall Roughness Profile for Commercial Steel Pipes

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
K. K. Botros
Keyword(s):  
Carbon Steel ◽  
Roughness Height ◽  
Outer Diameter ◽  
Wall Roughness ◽  
Steel Pipes ◽  
Roughness Profile ◽  
Wide Range ◽  
Commercial Carbon ◽  
Commercial Steel ◽  
The Relationship

The relationships between the sand grain roughness height (ks) in use with Nikuradse or Colebrook correlations for the roughness function (RF) and the internal pipe wall roughness element described by the root-mean-square (RMS) of the roughness profile (Rq) for turbulent flow in pipes are experimentally examined. Flow tests were conducted on a total of 13 commercial steel pipes of two sizes: 168.3 mm and 114.3 mm outer diameter (OD). The aim was to provide further insight into relationship between ks and Rq, for use with either RF correlations. The tests were conducted on high-pressure pipeline quality natural gas in the range of Reynolds number (based on pipe internal diameter) of 9 × 106–16 × 106. For commercial carbon steel pipes, the relationship between ks and Rq was found in the form ks=1.306  Rq+0.078  Rq2 and ks=2.294  Rq (both ks and Rq in μm), for use with Colebrook and Nikuradse RF correlations, respectively. These correlations cover a wide range of Rq from 2.7 μm to 12.5 μm which is typically found in commercial carbon steel pipes. For stainless steel (SS) pipes, preliminary results indicate that other surface roughness profile parameters need to be employed to better define the values of ks for these types of commercial steel pipes.

Design and Modeling of Soft Pneumatic Helical Actuator with High Contraction Ratio

2020 ◽  
Vol 32 (5) ◽  
pp. 1061-1070
Author(s):  
Peizheng Yuan ◽  
◽  
Ginjiro Kawano ◽  
Hideyuki Tsukagoshi
Keyword(s):  
Soft Materials ◽  
High Ratio ◽  
Outer Diameter ◽  
Initial Shape ◽  
Contraction Ratio ◽  
Wide Range ◽  
Pneumatic Power ◽  
Operating Distance ◽  
The Relationship ◽  
Two Sides

Soft contraction actuators are becoming important elements particularly for human-friendly robotic applications. However, it is challenging to achieve both a large operating distance while generating practical force. Hence, we present a new soft contraction actuator capable of realizing a high ratio contraction by pneumatic power. It can be easily fabricated using soft materials, including rubber tubes, one-way extensible cloth, and inextensible wire. Its initial shape is tubular but it can curve and coil to a helix shape owing to its different extensibilities on two sides when pressurized. A maximum contraction ratio of 78% and a 23 N contraction force can be achieved with an 11.6 mm initial outer diameter tube under 0.3 MPa. The effect of the tilt angle of a one-way extensible cloth on the helical shape is investigated, and a mathematical model illustrating the relationship between the contraction ratio and force is derived. Our experimental results suggest that this helical actuator has a much higher contraction ratio than a McKibben actuator under the same conditions. Finally, we discuss the potential application of the proposed actuator to a wearable device, i.e., for assisting the dorsiflexion of an ankle joint requiring a wide range of motion.

The Problem of Identifying and Modeling the Relationship between Monetary Factor and Inflation in the Russian Economy

2008 ◽  
pp. 61-76
Author(s):  
A. Porshakov ◽  
A. Ponomarenko
Keyword(s):  
Money Supply ◽  
Money Demand ◽  
Russian Economy ◽  
Long Run ◽  
Complex Approach ◽  
Wide Range ◽  
Long Time ◽  
The Relationship ◽  
Supply Side Factors

The role of monetary factor in generating inflationary processes in Russia has stimulated various debates in social and scientific circles for a relatively long time. The authors show that identification of the specificity of relationship between money and inflation requires a complex approach based on statistical modeling and involving a wide range of indicators relevant for the price changes in the economy. As a result a model of inflation for Russia implying the decomposition of inflation dynamics into demand-side and supply-side factors is suggested. The main conclusion drawn is that during the recent years the volume of inflationary pressures in the Russian economy has been determined by the deviation of money supply from money demand, rather than by money supply alone. At the same time, monetary factor has a long-run spread over time impact on inflation.

SAE 1020

Alloy Digest ◽  
1987 ◽  
Vol 36 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Carbon Steel ◽  
Low Carbon Steel ◽  
Heat Treating ◽  
Low Carbon ◽  
Steel Mills ◽  
Temperature Performance ◽  
Wide Range ◽  
Cold Worked

Abstract SAE 1020 is a low-carbon steel combining good machinability, workability and weldability. It is carburized for use in case-hardened components and it is used for a wide range of applications in the hot-worked, cold-worked, normalized or quenched-and-tempered conditions. Its many uses include bolts, rods, plate applications, machinery components, case-hardened parts, spinning tools and trimming dies. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on low temperature performance and corrosion resistance as well as heat treating, machining, joining, and surface treatment. Filing Code: CS-113. Producer or source: Carbon steel mills.

AISI 1566

Alloy Digest ◽  
1984 ◽  
Vol 33 (2) ◽  
Keyword(s):  
Carbon Steel ◽  
Heat Treating ◽  
Agricultural Machinery ◽  
High Carbon ◽  
Hand Tools ◽  
Steel Mills ◽  
Wide Range ◽  
Cold Worked ◽  
Hot Rolled ◽  
Good Workability

Abstract AISI 1566 is a high-carbon (nominally 0.66% carbon) steel containing 0.85-0.15% manganese. Its hardenability is low and on austenitizing and liquid quenching it develops a hard (martensitic) surface with a soft, ductile core. It can be used in the hot-rolled, annealed, normalized, cold-worked or liquid-quenched-and-tempered condition for a wide range of applications. It has good machinability and good workability. Its many uses include springs, shafts, hand tools, railway parts and agricultural machinery. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: CS-100. Producer or source: Carbon steel mills.

scholarly journals Polymorphic Iterable Sequential Effect Systems

2021 ◽  
Vol 43 (1) ◽  
pp. 1-79
Author(s):  
Colin S. Gordon
Keyword(s):  
Algebraic Structure ◽  
Position Effect ◽  
Type Systems ◽  
Sequential Effect ◽  
Prior Work ◽  
Sequential Effects ◽  
Wide Range ◽  
The Relationship ◽  
Categorical Semantics

Effect systems are lightweight extensions to type systems that can verify a wide range of important properties with modest developer burden. But our general understanding of effect systems is limited primarily to systems where the order of effects is irrelevant. Understanding such systems in terms of a semilattice of effects grounds understanding of the essential issues and provides guidance when designing new effect systems. By contrast, sequential effect systems—where the order of effects is important—lack an established algebraic structure on effects. We present an abstract polymorphic effect system parameterized by an effect quantale—an algebraic structure with well-defined properties that can model the effects of a range of existing sequential effect systems. We define effect quantales, derive useful properties, and show how they cleanly model a variety of known sequential effect systems. We show that for most effect quantales, there is an induced notion of iterating a sequential effect; that for systems we consider the derived iteration agrees with the manually designed iteration operators in prior work; and that this induced notion of iteration is as precise as possible when defined. We also position effect quantales with respect to work on categorical semantics for sequential effect systems, clarifying the distinctions between these systems and our own in the course of giving a thorough survey of these frameworks. Our derived iteration construct should generalize to these semantic structures, addressing limitations of that work. Finally, we consider the relationship between sequential effects and Kleene Algebras, where the latter may be used as instances of the former.

Improvement of Integrity Concepts for NPP Primary Circuit Piping

2008 ◽  
Author(s):  
Alexey Arzhaev ◽  
Sergey Butorin
Keyword(s):  
Carbon Steel ◽  
General Scheme ◽  
Primary Circuit ◽  
Feed Water ◽  
Outer Diameter ◽  
Intergranular Stress Corrosion ◽  
Methodology Development ◽  
Integrity Assessment ◽  
Piping Systems ◽  
Steel Piping

Operating NPPs license extension activities in Russia produced strong demand for safety improvement of plants build according to earlier standards. Installation of additional supports as pipe whip restraints is one of requirement in acting regulatory documentation which should be followed or compensated by appropriate measures like Leak Before Break (LBB) analyses and improvement of In-Service Inspection (ISI) and Leak Detecting System (LDS). Basic document for LBB concept application to Russian NPP piping is RD 95 10547-99. Its requirements correspond to classical LBB principles used in many countries in Europe, USA and Japan. In many real cases requirements of RD 95 10547-99 could not be applied to safety important NPP piping systems due to the presence of specific features of operational degradation due to some corrosion mechanisms: for example, erosion-corrosion (E-C) for carbon steel piping and intergranular stress corrosion cracking (IGSSC) for heat affected zones of austenitic piping weldments. For special case of RBMK piping with outer diameter 325 mm (potentially susceptible to IGSCC) special Break Preclusion Concept has been developed in Russia after IAEA Extrabudgetary Program in 2000–2002. Contrary to LBB Concept demanding for all four basic principles to be completely fulfilled BP Concept accepts some principles to be fulfilled in a balanced way with demonstration of monitored degradation effectively achieved in operation. Special BP Concept is being developed now to support integrity assessment of RBMK carbon steel steam and feed water piping potentially susceptible to E-C which requires another set of measures to demonstrate principle of controlled degradation in operation then in case of austenitic steel piping. General scheme of piping integrity analyses according to LBB and BP Concepts is discussed and examples of specific approaches to achieve controlled degradation are illustrated in paper. As result of LBB and BP Concepts application it is possible to substantiate reject of additional piping whip restraints implementation on-site. Examples of similar safety methodology development in other countries have been reported at IAEA Specialists Meeting on LBB in Kiev, Ukraine in November 2006.

Age-Dependency of Total Tau in the Cerebrospinal Fluid Is Corrected by Amyloid-β 1–40: A Correlational Study in Healthy Adults

2021 ◽  
pp. 1-8
Author(s):  
Paul Theo Zebhauser ◽  
Achim Berthele ◽  
Marie-Sophie Franz ◽  
Oliver Goldhardt ◽  
Janine Diehl-Schmid ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Amyloid Β ◽  
Healthy Adults ◽  
Tau Proteins ◽  
Clinical Settings ◽  
Inclusion Criteria ◽  
Total Tau ◽  
Potential Marker ◽  
Wide Range ◽  
The Relationship

Background: Tau proteins are established biomarkers of neuroaxonal damage in a wide range of neurodegenerative conditions. Although measurement of total-Tau in the cerebrospinal fluid is widely used in research and clinical settings, the relationship between age and total-Tau in the cerebrospinal fluid is yet to be fully understood. While past studies reported a correlation between age and total-Tau in the cerebrospinal fluid of healthy adults, in clinical practice the same cut-off value is used independently of patient’s age. Objective: To further explore the relationship between age and total-Tau and to disentangle neurodegenerative from drainage-dependent effects. Methods: We analyzed cerebrospinal fluid samples of 76 carefully selected cognitively healthy adults and included amyloid-β 1–40 as a potential marker of drainage from the brain’s interstitial system. Results: We found a significant correlation of total-Tau and age, which was no longer present when correcting total-Tau for amyloid-β 1–40 concentrations. These findings were replicated under varied inclusion criteria. Conclusion: Results call into question the association of age and total-Tau in the cerebrospinal fluid. Furthermore, they suggest diagnostic utility of amyloid-β 1–40 as a possible proxy for drainage-mechanisms into the cerebrospinal fluid when interpreting biomarker concentrations for neurodegenerative diseases.

scholarly journals Modelling the elastic mechanical properties of bioactive glass-derived scaffolds

2020 ◽  
Vol 6 (1) ◽  
pp. 50-56
Author(s):  
Francesco Baino ◽  
Elisa Fiume
Keyword(s):  
Elastic Properties ◽  
Poisson’S Ratio ◽  
Mechanical Performance ◽  
Solid Material ◽  
Poisson's Ratio ◽  
Predictive Capability ◽  
Shear Moduli ◽  
Wide Range ◽  
Constitutive Parameters ◽  
The Relationship

AbstractPorosity is known to play a pivotal role in dictating the functional properties of biomedical scaffolds, with special reference to mechanical performance. While compressive strength is relatively easy to be experimentally assessed even for brittle ceramic and glass foams, elastic properties are much more difficult to be reliably estimated. Therefore, describing and, hence, predicting the relationship between porosity and elastic properties based only on the constitutive parameters of the solid material is still a challenge. In this work, we quantitatively compare the predictive capability of a set of different models in describing, over a wide range of porosity, the elastic modulus (7 models), shear modulus (3 models) and Poisson’s ratio (7 models) of bioactive silicate glass-derived scaffolds produced by foam replication. For these types of biomedical materials, the porosity dependence of elastic and shear moduli follows a second-order power-law approximation, whereas the relationship between porosity and Poisson’s ratio is well fitted by a linear equation.

Sign in / Sign up

Export Citation Format

Share Document