scholarly journals INVESTIGATION INTO TT TECHNOLOGICAL PROPERTIES OF COOLANTS WITH LIQUID CRYSTAL ADDITIVES / TEPIMO IR AUŠINIMO SKYSČIO SU SKYSTŲJŲ KRISTALŲ PRIEDAIS TECHNOLOGINIŲ SAVYBIŲ TYRIMAS

2012 ◽  
Vol 3 (6) ◽  
pp. 71-74
Author(s):  
Vaidas Strolia ◽  
Vadim Mokšin ◽  
Robertas Urbanavičius
Keyword(s):  
Liquid Crystals ◽  
Comparative Research ◽  
Liquid Crystalline ◽  
Work Piece ◽  
Machined Surface ◽  
Mineral Oils ◽  
Twisted Nematic ◽  
Iron Work ◽  
Cutting Zone ◽  
Oil Emulsions

The paper presents the results of comparative research on the roughness and tool life of the machined surface when steel and cast iron work pieces were turned, reamed and tapped and the cutting zone was lubricated by various coolants (mineral oils, oil emulsions) with and without twisted nematic liquid crystals. The tested liquid crystals were taken from the same homologous series (fatty acid cholesterol esters) but had different molecular mass. It has been established that the most positive tribological effect of liquid crystalline additives is achieved when high-molecular liquid crystals are used in operations characterized by the largest tool-work piece interface area (reaming, threading). Santrauka Straipsnyje pateikti apdirbto paviršiaus šiurkštumo ir įrankių patvarumo matavimo rezultatai, kai plieno ir ketaus paviršiai buvo tekinami, plečiami ir sriegiami sriegikliais, pjovimo zoną tepant ir aušinant įvairiais tepimo ir aušinimo skysčiais su cholesterinių skystųjų kristalų priedais ir be priedų. Buvo naudojami skirtingos molekulinės masės vienos homologinės eilės cholesteriniai skystieji kristalai (cholesterolio esteriai) ir skirtingi tepimo ir aušinimo skysčiai: tepalai ir mineralinių tepalų vandens emulsijos. Nustatyta, kad didžiausias teigiamas skystųjų kristalų priedų efektas pasiekiamas tų operacijų metu, kai įrankio ir detalės kontakto plotas yra didesnis (pvz., plečiant, sriegiant). Taip pat nustatyta, kad didžiausiu tribologiniu efektu pasižymi didesnės molekulinės masės skystieji kristalai.

The electrohydrodynamic instability in twisted nematic liquid crystals

1994 ◽  
Vol 4 (2) ◽  
pp. 239-252 ◽  
Author(s):  
A. Hertrich ◽  
A. P. Krekhov ◽  
O. A. Scaldin
Keyword(s):  
Liquid Crystals ◽  
Nematic Liquid Crystals ◽  
Electrohydrodynamic Instability ◽  
Twisted Nematic

Liquid-crystalline behaviour and electrorheological effect of phthalocyanine-based ionic liquid crystals

2020 ◽  
pp. 1-10
Author(s):  
Aikebaier Reheman ◽  
Shuangying Hu ◽  
Lianjun Cao ◽  
Danhua Xie ◽  
Guiyang Yan ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Electrorheological Effect ◽  
Ionic Liquid Crystals

Flank-milling of Integral Blade Rotors made in Ti6Al4V using cryo CO2 and Minimum Quantity Lubrication (MQL)

2021 ◽  
pp. 1-16
Author(s):  
Haizea Gonzalez ◽  
Octavio Pereira ◽  
Luis Norberto López de Lacalle ◽  
Amaia Calleja ◽  
Izaro Ayesta ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Cutting Tools ◽  
Minimum Quantity Lubrication ◽  
Cryogenic Cooling ◽  
Flank Milling ◽  
New Device ◽  
Minimum Quantity ◽  
Cutting Zone ◽  
Oil Emulsions ◽  
Pcd Tools

Abstract This paper presents the machining of Ti6Al4V Integral Blade Rotors (IBR) using CO2 as cryogenic cooling. This kind of component is typical in gas turbines, pumps and other rotary machines. Flank milling technique using diamond polycrystalline (PCD) tools using CO2 and Minimum Quantity Lubrication (MQL), denominated CryoMQL, is an alternative to conventional oil emulsions. The proposed approach implies a balance between technical and environmental issues, and it makes feasible the use PCD tools avoiding the high temperature reactivity of Ti6Al4V alloy with this type of cutting tools. CO2 must be supplied and injected onto the cutting zone, avoiding the risks of dry ice formation and clogging of both pipes and nozzles. For this purpose, a new device for CO2 delivery was developed, using gas and liquid CO2.

Substrate induced freezing, melting and depinning transitions in two-dimensional liquid crystalline systems

2022 ◽  
Author(s):  
Bharti bharti ◽  
Debabrata Deb
Keyword(s):  
Molecular Dynamics ◽  
Liquid Crystals ◽  
Molecular Dynamics Simulations ◽  
Liquid Crystalline ◽  
Two Dimensional ◽  
One Dimensional ◽  
The One ◽  
Dynamics Simulations

We use molecular dynamics simulations to investigate the ordering phenomena in two-dimensional (2D) liquid crystals over the one-dimensional periodic substrate (1DPS). We have used Gay-Berne (GB) potential to model the...

scholarly journals Analysis of Forces in Vibro-Impact and Hot Vibro-Impact Turning of Advanced Alloys

2011 ◽  
Vol 70 ◽  
pp. 315-320 ◽  
Author(s):  
Riaz Muhammad ◽  
Agostino Maurotto ◽  
Anish Roy ◽  
Vadim V. Silberschmidt
Keyword(s):  
Finite Element ◽  
Cutting Forces ◽  
Three Dimensional ◽  
Element Model ◽  
Machining Process ◽  
Strain Rates ◽  
Machining Processes ◽  
Machined Surface ◽  
Cutting Zone

Analysis of the cutting process in machining of advanced alloys, which are typically difficult-to-machine materials, is a challenge that needs to be addressed. In a machining operation, cutting forces causes severe deformations in the proximity of the cutting edge, producing high stresses, strain, strain-rates and temperatures in the workpiece that ultimately affect the quality of the machined surface. In the present work, cutting forces generated in a vibro-impact and hot vibro-impact machining process of Ti-based alloy, using an in-house Ultrasonically Assisted Turning (UAT) setup, are studied. A three-dimensional, thermo-mechanically coupled, finite element model was developed to study the thermal and mechanical processes in the cutting zone for the various machining processes. Several advantages of ultrasonically assisted turning and hot ultrasonically assisted turning are demonstrated when compared to conventional turning.

Liquid crystals for twisted nematic display devices

1999 ◽  
Vol 9 (9) ◽  
pp. 2037-2050 ◽  
Author(s):  
George W. Gray ◽  
Stephen M. Kelly
Keyword(s):  
Liquid Crystals ◽  
Display Devices ◽  
Twisted Nematic

State transition at electrohydrodynamic convection of twisted nematic liquid crystals

2018 ◽  
Vol 98 (5) ◽  
Author(s):  
Chul Gyu Jhun ◽  
Gyu Jin Choi ◽  
Dae Geon Ryu ◽  
Jong-Hoon Huh ◽  
Jin Seog Gwag
Keyword(s):  
Liquid Crystals ◽  
State Transition ◽  
Nematic Liquid Crystals ◽  
Twisted Nematic

Kinetics of Field Alignment and Elastic Relaxation in Twisted Nematic Liquid Crystals

1974 ◽  
pp. 115-123 ◽  
Author(s):  
T. S. Chang ◽  
P. E. Greene ◽  
E. E. Loebner
Keyword(s):  
Liquid Crystals ◽  
Nematic Liquid Crystals ◽  
Twisted Nematic ◽  
Kinetics Of

Experimental and computational (DFT) studies on induced orthogonal smectic A∗ phase in hydrogen-bonded ferroelectric liquid crystals

2018 ◽  
Vol 32 (21) ◽  
pp. 1850223 ◽  
Author(s):  
P. Subhasri ◽  
R. Jayaprakasam ◽  
V. N. Vijayakumar
Keyword(s):  
Liquid Crystals ◽  
Molecular Orbital ◽  
Density Functional ◽  
Liquid Crystalline ◽  
Proton Acceptor ◽  
Dft Studies ◽  
Ferroelectric Liquid Crystals ◽  
Smectic A ◽  
Present Complex ◽  
Hydrogen Bonded

Hydrogen-bonded ferroelectric liquid crystals (HBFLC) are designed and synthesized from nonmesogenic chiral proton donor compound of (R)-([Formula: see text])-Methylsuccinic acid (MSA) and mesogenic proton acceptor compound of 4-undecyloxybenzoic acid (11OBA) in a different mole ratio. Intermolecular hydrogen bonds (H-bond) between the nonmesogenic and mesogenic compounds have been confirmed through experimental Fourier transform infrared spectroscopy (FTIR) and density functional theory (DFT) computational studies. The steric hindrance and inductive effects of the present complex and its influence on the structure are discussed. A rich phase polymorphism in the liquid crystalline complex has been studied using polarizing optical microscope (POM) and differential scanning calorimetry (DSC). The chiral phases observed in the present complex are due to the presence of lone pair (n) to anti-bonding ([Formula: see text]) transition symmetry which is validated by DFT studies. A noteworthy observation of induced smectic A[Formula: see text](Sm A[Formula: see text]) by quenching of traditional phase (nematic) has been identified and the reason for the same has been discussed by DFT studies. The unusual phase order of Sm A[Formula: see text], smectic C[Formula: see text](Sm C[Formula: see text]) and smectic G[Formula: see text][Formula: see text](Sm G[Formula: see text]) mesogenic phases are observed. The other liquid crystalline parameters are evaluated by experimental and theoretical calculations and the same has been compared. Increased tilt angle in liquid crystal (LC) molecules has been theoretically analyzed by natural bond orbital (NBO) studies. Stability of the HBFLC phases and its origination mechanism have been discussed with the help of highest occupied molecular orbital and lowest unoccupied molecular orbital (HOMO–LUMO) energies.

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