Effect of lubricant rheology on friction in coated elastohydrodynamic lubricated contacts

2016 ◽  
Vol 231 (8) ◽  
pp. 975-985 ◽  
Author(s):  
W Habchi ◽  
S Bair
Keyword(s):  
Thermal Inertia ◽  
Soft Material ◽  
Hard Material ◽  
Lubricated Contacts ◽  
Coating Type ◽  
Lubricant Rheology ◽  
High Thermal Inertia ◽  
Relative Friction

This work investigates the effect of lubricant rheology on friction in coated elastohydrodynamic contacts. Two lubricants with relatively different properties are selected and two coating configurations are considered. The first coating type consists of a soft material with a low thermal inertia while the second is a hard material with a high thermal inertia. The former is known to decrease friction while the latter increases it compared to uncoated contacts. The original expectation was that the lubricant with higher P–T dependence of viscosity would exhibit higher relative friction deviation from the uncoated case. It turned out that this is only true in the linear and thermoviscous friction regimes at low and high slide-to-roll ratios, respectively.

scholarly journals Thermal modes of space objects with high thermal inertia

2017 ◽  
pp. 267-274
Author(s):  
M.M. Penkov ◽  
A.M. Dzitoev ◽  
E.V. Lapovok ◽  
S.I. Khankov
Keyword(s):  
Thermal Inertia ◽  
Space Objects ◽  
High Thermal Inertia

New Reactor Safety Measures for the European Sodium Fast Reactor - Part I: Conceptual Design

2021 ◽  
Author(s):  
Joel Guidez ◽  
Janos Bodi ◽  
Konstantin Mikityuk ◽  
Enrico Girardi ◽  
Bernard Carluec
Keyword(s):  
Fast Reactor ◽  
Heat Removal ◽  
Thermal Inertia ◽  
Lessons Learned ◽  
Reactor Safety ◽  
Fukushima Accident ◽  
Safety Level ◽  
Safety Measures ◽  
Sodium Fast Reactor ◽  
High Thermal Inertia

Abstract Following up the previous CP-ESFR project, the ESFR-SMART project considers the safety objectives envisaged for Generation-IV reactors, taking into account the lessons learned from the Fukushima accident, in order to increase the safety level of the European Sodium Fast Reactor (ESFR). In accordance with these objectives, guidelines have been defined to drive the ESFR-SMART developments, mainly simplifying the design and using all the positive features of Sodium Fast Reactors (SFR), such as low coolant pressure, efficiency of natural convection, possibility of decay heat removal (DHR) by atmospheric air, high thermal inertia and long grace period before a human intervention is needed. In this paper, a set of new ambitious safety measures is introduced for further evaluation within the project. The proposed set aims at consistency with the main lines of safety evolutions since the Fukushima accident, but it does not yet constitute the final comprehensive safety analysis. The paper gives a first review of the new propositions to enhance the ESFR safety, leading to a simplified reactor, forgiving and including a lot of passivity. This first version is supported by the various project tasks in order to assess the relevance of the whole design in comparison to the final safety objectives.

A thermal model of the sailback pelycosaur

Paleobiology ◽  
1986 ◽  
Vol 12 (4) ◽  
pp. 450-458 ◽  
Author(s):  
Steven C. Haack
Keyword(s):  
Thermal Model ◽  
Energy Exchange ◽  
Thermal Inertia ◽  
Significant Problem ◽  
Internal Temperature ◽  
Warm Up ◽  
Excess Heat ◽  
Thermal Regimes ◽  
High Thermal Inertia ◽  
Standard Techniques

Standard techniques of energy exchange analysis are applied to modelling the thermal regimes of several species of sailback pelycosaurs. Of particular interest is the role played by the sail in thermoregulation. Although the sail did increase the rate at which the model could warm up in the morning, its effectiveness fell short of previous estimates. The sail increased the daytime internal temperature by typically 3°C to 6°C. The more massive subjects had the highest temperature increases owing partly to their higher thermal inertia and partly to their disproportionately large sails. The sail had no impact upon the nocturnal minimums in temperature.Overheating does not appear to have been a significant problem in the Permian environment, particularly in view of the high thermal inertia of the subjects modeled. When overheating occurred, the sail was of limited value for dumping excess heat.

scholarly journals Novel active method for the estimation of a building wall thermal resistance

2020 ◽  
Vol 172 ◽  
pp. 14008
Author(s):  
Adrien François ◽  
Laurent Ibos ◽  
Vincent Feuillet ◽  
Johann Meulemans
Keyword(s):  
Steady State ◽  
Thermal Resistance ◽  
Building Materials ◽  
Thermal Inertia ◽  
Thermal Response ◽  
Heat Fluxes ◽  
External Temperature ◽  
Building Wall ◽  
High Thermal Inertia

The thermal resistance of a wall can be readily measured in steady-state. However, such a state is seldomly achieved in a building because of the variation of outdoor conditions as well as the high thermal inertia of building materials. This paper introduces a novel active (dynamic) method to measure the thermal resistance of a building wall. Not only are active approaches less sensitive to external temperature variations, they also enable to perform measurements within only a few hours. In the proposed methodology, an artificial thermal load is applied to a wall (heating of the indoor air) and its thermal response is monitored. Inverse techniques are used with a reduced model to estimate the value of the thermal resistance of a wall from the measured temperatures and heat fluxes. The methodology was validated on a known load-bearing wall built inside a climate chamber. The results were in good agreement with reference values derived from a steady-state characterization of the wall. The method also demonstrated a good reproducibility.

Design Methodologies for Soft-Material Robots Through Additive Manufacturing, From Prototyping to Locomotion

2015 ◽  
Author(s):  
Eliad Cohen ◽  
Vishesh Vikas ◽  
Barry Trimmer ◽  
Stephen McCarthy
Keyword(s):  
Additive Manufacturing ◽  
Modular Design ◽  
Technological Development ◽  
Deformable Body ◽  
Soft Materials ◽  
Soft Material ◽  
Hard Material ◽  
Hard Component ◽  
Contact Points ◽  
Manufacturing Techniques

Soft material robots have gained interest in recent years due to the mechanical potential of non-rigid materials and technological development in the additive manufacturing (3D printing) techniques. The incorporation of soft materials provides robots with potential for locomotion in unstructured environments due to the conformability and deformability properties of the structure. Current additive manufacturing techniques allow multimaterial printing which can be utilized to build soft bodied robots with rigid-material inclusions/features in a single process, single batch (low manufacturing volumes) thus saving on both design prototype time and need for complex tools to allow multimaterial manufacturing. However, design and manufacturing of such deformable robots needs to be analyzed and formalized using state of the art tools. This work conceptualizes methodology for motor-tendon actuated soft-bodied robots capable of locomotion. The methodology relies on additive manufacturing as both a prototyping tool and a primary manufacturing tool and is categorized into body design & development, actuation and control design. This methodology is applied to design a soft caterpillar-like biomimetic robot with soft deformable body, motor-tendon actuators which utilizes finite contact points to effect locomotion. The versatility of additive manufacturing is evident in the complex designs that are possible when implementing unique actuation techniques contained in a soft body robot (Modulus discrepancy); For the given motor-tendon actuation, the hard tendons are embedded inside the soft material body which acts as both a structure and an actuator. Furthermore, the modular design of soft/hard component coupling is only possible due to this manufacturing technique and often eliminates the need for joining and fasteners. The multi-materials are also used effectively to manipulate friction by utilizing soft/hard material frictional interaction disparity.

scholarly journals MODELING OF THERMAL MODES OF THE REFLUX CONDENSER OF THE ABSORPTION REFRIGERATION UNIT

2017 ◽  
Vol 3 ◽  
pp. 31-40
Author(s):  
Andrey Kholodkov ◽  
Aleksandr Titlov
Keyword(s):  
Thermal Inertia ◽  
Ammonia Vapor ◽  
Absorption Refrigeration ◽  
Reflux Condenser ◽  
Operating Modes ◽  
Refrigeration Equipment ◽  
Refrigeration Unit ◽  
High Thermal Inertia ◽  
Standard Designs ◽  
Experimental Researches

Currently, developers of modern refrigeration equipment, in accordance with the plans of the UN, are moving to natural refrigerants (hydrocarbons, carbon dioxide and ammonia) that do not have an adverse technological impact on the ecosystem of the planet. In domestic refrigeration technology, one of the options is absorption refrigeration units, the working body of which is an aqueous ammonia mixture with the hydrogen addition. Having a number of unique advantages over compression analogs, absorption systems are characterized by lower energy characteristics. As the analysis shows, the maximum thermodynamic losses in the absorption aggregates are concentrated in the generating unit when the ammonia is evaporated, it is purified from water vapor and transported to the evaporator. In this connection, the mathematical modeling of the thermal regimes of the reflux condenser is performed, which is responsible for purification and transportation of ammonia vapor. Modeling is carried out on standard designs of absorption refrigeration units taking into account reasonable assumptions and results of own experimental researches. A cellular model is used. Stationary operating modes are modeled due to the high thermal inertia of the processes in the reflux condenser. As a result, the perspective of the thermal insulation installation throughout the reflux section is shown, which makes it possible to increase the energy efficiency by 17 ... 22 %

scholarly journals TINJAUAN ASPEK KELAYAKAN ELEMEN PEMBENTUK RUANG KOMUNAL DI TAMAN MONUMEN 45 KOTA PEKALONGAN

2016 ◽  
Vol 18 (1) ◽  
pp. 47-54
Author(s):  
Moch Fathoni Setiawan ◽  
Andi Purnomo
Keyword(s):  
Soft Material ◽  
Hard Material ◽  
Group Area ◽  
Communal Space ◽  
The City ◽  
City Park

Taman Monumen 45 is one of the city park in Pekalongan City, in which there are statues of the heroes as monument to commemorate the services of the heroes. In this park there are also garden element in shape of hard elements and soft elements. Some hard elements are sitting group, pedestrian area, sports area, and the statue of the heroes (sculpture). The hard elements are referred to support the communal activity for the citizens of Pekalongan. They are functioned as for gathering and chatting, lounging, skateboarding and BMX styling. This study aims to assess the feasibility aspects in Taman Monumen 45 in Pekalongan City. From the research, it was revealed that there are some elements of the park that do not meet the eligibility aspect as constituting elements of communal space. It can be seen from the condition of these elements, either hard material or soft material that is still less maintained and is not in accordance with its function.Taman Monumen 45 merupakan salah satu taman kota di Kota Pekalongan yang mana di sana terdapat patung pahlawan sebagai monumen untuk mengenang jasa para pahlawan. Pada taman ini juga terdapat elemen taman berupa elemen keras (hard material) dan elemen lunak (soft material). Elemen keras pada taman ini diantaranya sitting group, area pedestrian, sport area, dan patung pahlawan (sculpture). Elemen keras tersebut sebagai salah satu pendukung aktifitas komunal bagi warga Kota Pekalongan seperti berkumpul, mengobrol dan duduk santai, tempat bermain skateboard dan BMX style. Penelitian ini bertujuan untuk mengkaji aspek kelayakan pada Taman Monumen 45 di Kota Pekalongan. Dari hasil penelitian, terungkap bahwa ada beberapa elemen taman yang tidak memenuhi aspek kelayakan sebagai pembentuk elemen ruang komunal. Hal ini dapat dilihat dari kondisi elemen-elemen tersebut, baik hard material atau soft material yang masih kurang terawat dan tidak sesuai dengan fungsinya.

scholarly journals Transient Cooling Of A Cylinder In Cross Flow Bounded By An Adiabatic Wall

2018 ◽  
Vol 17 (2) ◽  
pp. 17
Author(s):  
Nawaf H Saeid ◽  
Bashir S. Abusahmin
Keyword(s):  
Thermal Properties ◽  
Cross Flow ◽  
Thermal Inertia ◽  
Cooling Process ◽  
Adiabatic Wall ◽  
Cold Air ◽  
Cooling Period ◽  
Air Stream ◽  
Storage Area ◽  
High Thermal Inertia

The present study investigates the parameters controlling the cooling process of acylindrical food in the storage area for a period of time. Transient analysis of theconduction and convection (conjugate) heat transfer from a cylindrical food, or acylindrical can filled with food is selected for numerical simulations. The cylinder isbounded by an adiabatic wall and the cold air is flowing normal to the cylinder axis (crossflow). The parameters investigated are: Reynolds number, food thermal properties(density, specific heat and thermal conductivity) and the cooling period. The range of theReynolds number is selected from 50 to 500 to be in laminar flow conditions. Threedifferent materials were selected according their thermal properties. The results arepresented to show the cooling process starting from blowing cold air stream on thecylinder for a period of 4 hours. The results show that the food with low thermal inertia iscooled faster than that of high thermal inertia. The present results show also that thecooling process can be shortened by increasing the air velocity and lower its temperature.

High Thermal Inertia Zones on Ceres From Dawn Data

2020 ◽  
Vol 125 (3) ◽  
Author(s):  
E. Rognini ◽  
M. T. Capria ◽  
F. Tosi ◽  
M. C. De Sanctis ◽  
M. Ciarniello ◽  
...  
Keyword(s):  
Thermal Inertia ◽  
High Thermal Inertia
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