Thermal Shrinkage of Oriented Nylon 66 Yarns as a Function of Time, Temperature, and Stress

1969 ◽  
Vol 39 (5) ◽  
pp. 428-434 ◽  
Author(s):  
Arthur Ribnick
Keyword(s):  
Activation Energy ◽  
Hydrogen Bonds ◽  
Displacement Transducer ◽  
Thermal Shrinkage ◽  
Nonlinear Functions ◽  
Nylon 66 ◽  
Linear Variable Displacement Transducer ◽  
Variable Displacement

A method employing a linear variable displacement transducer has been adapted to measure the thermal shrinkage of oriented yarns of nylon 66. The thermal shrinkage of this material has been found to be viscoelastic in that nonlinear functions of time, temperature, and stress are required to describe the shrinkage. The activation energy has been estimated to be 40 kcal per mole, which is partly explainable by a dissociation of the hydrogen bonds in the amide groups.

The Thermal Shrinkage of an Oriented Polyester Yarn as a Function of Time, Temperature, and Stress

1969 ◽  
Vol 39 (8) ◽  
pp. 742-748 ◽  
Author(s):  
Arthur Ribnick
Keyword(s):  
Activation Energy ◽  
Displacement Transducer ◽  
Semicrystalline Polymers ◽  
Thermal Shrinkage ◽  
Stress Dependence ◽  
Kcal Mole ◽  
Polyester Yarn ◽  
Proposed Model ◽  
Linear Variable Displacement Transducer ◽  
Variable Displacement

Measurements have been made with a linear variable-displacement transducer of the thermal shrinkage of an oriented polyester yarn in dry nitrogen as a function of time, temperature, and stress. The shrinkage of this material has been found to be nonlinear with respect to these three variables. A modified form of the Tobolsky and Eyring creep-rate equation has been found to describe the temperature and stress dependence. The activation energy for the process has been estimated to be 55.6 kcal/mole and the displacement volume to be 810 Å3. Interpretation of these experimental results appears to support a recently proposed model that thermal shrinkage of oriented semicrystalline polymers is a reflection of a structural transformation between extended-chain and folded-chain crystallites.

scholarly journals Structural and physical evaluation of a reinforced beam using strain gauges

2022 ◽  
Vol 2153 (1) ◽  
pp. 012003
Author(s):  
N Afanador-Garcia ◽  
G Guerrero-Gomez ◽  
R Gallardo-Amaya
Keyword(s):  
Concrete Beam ◽  
Maximum Load ◽  
Reinforced Concrete Beam ◽  
Displacement Transducer ◽  
Bending Test ◽  
Strain Gauges ◽  
Physical Behavior ◽  
Linear Variable Displacement Transducer ◽  
Strength Tests ◽  
Variable Displacement

Abstract In this research project,the deformations in the longitudinal and transverse reinforcing steel of a reinforced concrete beam with 2ϕ½” were estimated.Additionally,the displacements in thecenter of thespanweremeasuredtogether with theloads, which generatedthecrackingof the beam of dimensions180 mm×240 mm×3100 mm.Displacement were performed using a linear variable displacement transducer, and strain gauges were used to measure deformations. Finally, the applied load’s measurements were obtained with a load cell Pinzuar/Model-100/20T equipment.The physical-mechanical properties of the concreteused were determined through compressive strength tests at 28 days and modulus of elasticity.For this purpose, a load-bearing frame was used to support the beam at three points for load application.The data was collected directly on the Quantum/X2 equipment and analyzed with the help of the Catman/AP software.The maximum deformations found in the bending test at three point since there inforced concrete beam we are not greater than 8483µm/mm,presenting a failure in the center of the beam due to the creep of the tensile steel for a maximum load of 3115 Kg.Finally,the physical behavior of there inforced concrete beam with applying aload allows evaluating and optimizing this kind of systems.

scholarly journals Analisis lendutan balok beton secara eksperimental dan perhitungan metode elemen hingga (MEH) dengan aplikasi SNI 2847 : 2013

2018 ◽  
Vol 12 (3) ◽  
pp. 127-134
Author(s):  
Tri Handayani ◽  
Yudi Irawadi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Displacement Transducer ◽  
Linear Variable Displacement Transducer ◽  
Variable Displacement ◽  
Element Method

Pada makalah ini disajikan analisis lendutan balok beton dari sebuah gedung. Analisa dilakukan menggunakan software berbasis finite element method (FEM) dan eksperimental dengan tujuan untuk mengetahui pengaruh jenis tumpuan dan tipe penampang balok terhadap lendutan.Dalam analisis menggunakan software FEM dilakukan perhitungan lendutan menggunakan persamaan lendutan balok pada dua tumpuan dengan asumsi sebagai penampang balok biasa dan penampang balok T. Selain itu, juga diperhitungkan kondisi tumpuan yaitu sebagai tumpuan sederhana dan tumpuan jepit-jepit. Dalam evaluasi secara eksperimental dilakukan uji beban terhadap balok beton yang bersangkutan sesuai SNI 2847 2013. Sebagai beban uji adalah air dan sebagai pengukur lendutan adalah linear variable displacement transducer (LVDT). Perhitungan lendutan di tengah bentang dengan software berbasis FEM dengan asumsi balok T dan tumpuan jepit-jepit menghasilkan lendutan untuk balok C 1-2 sebesar 1,652 mm dan untuk balok 2 A-B sebesar 1,987 mm. Lendutan netto di tengah bentang hasil uji beban untuk balok C 1-2 adalah sebesar 1,263 mm dan untuk balok 2 A-B adalah sebesar 1,625 mm. Dengan demikian pada eksperimen ini dapat disimpulkan bahwa lendutan balok beton hasil evaluasi menggunakan software FEM melalui perhitungan dengan asumsi penampang balok T dengan kondisi tumpuan jepit-jepit adalah yang paling mendekati lendutan hasil evaluasi secara eksperimental melalui uji beban

Micro Impact Testing of Lead Free Solder Joints

2008 ◽  
Vol 32 ◽  
pp. 99-102
Author(s):  
Ranjan Rajoo ◽  
Erich H. Kisi ◽  
D.J. O'Connor
Keyword(s):  
Solder Joint ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Intermetallic Layer ◽  
Displacement Transducer ◽  
Impact Testing ◽  
Lead Free ◽  
Linear Variable Displacement Transducer ◽  
Free Solder

This paper presents data obtained from a newly-developed instrument to test the quality of solder interconnections at high strain rate – the ‘micro-impactor’. This shear test of the interconnection at high strain rate mimics the stress experienced by the solder joint when undergoing shock due to drop-impact. Instrumented with a load cell and linear variable displacement transducer (LVDT), it also has the ability to provide dynamic impact force and displacement data. Earlier concepts to characterise the solder joint at high strain rates such as the miniature pendulum impact tester [1] lacked this capability. This micro-impactor was used to study the effect of increasing silver (Ag) and copper (Cu) concentration in solder alloys on the shear strength of the solder joint. The performance of these lead-free alloys was also compared to that of the well-established leaded solder. It was found that increasing the silver content increases the yield strength of the solder, causing the failure to occur at the brittle intermetallic layer instead of in the bulk of the solder.

scholarly journals Interplay between spin crossover and proton migration along short strong hydrogen bonds

2021 ◽  
Author(s):  
Verónica Jornet-Mollá ◽  
Carlos Giménez-Saiz ◽  
Laura Cañadillas-Delgado ◽  
Dmitry S. Yufit ◽  
Judith A. K. Howard ◽  
...  
Keyword(s):  
Activation Energy ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Low Temperatures ◽  
Energy Barrier ◽  
Spin Crossover ◽  
Strong Hydrogen Bond ◽  
Activation Energy Barrier ◽  
Proton Migration

A proton migration across a short strong hydrogen bond can be triggered by spin crossover of a remote Fe2+ cation, with the onset of a photoinduced activation energy barrier for proton motion at low temperatures.

Static and vibration characteristics of thin-walled box beams: An experimental investigation

2017 ◽  
Vol 20 (10) ◽  
pp. 1540-1559 ◽  
Author(s):  
Kiana Kashefi ◽  
Abdul Hamid Sheikh ◽  
Michael C Griffith ◽  
MS Mohamed Ali ◽  
Kazuo Tateishi
Keyword(s):  
Three Dimensional ◽  
Time History ◽  
Displacement Transducer ◽  
Vibration Characteristics ◽  
Element Analysis ◽  
Linear Variable Displacement Transducer ◽  
Dimensional Finite Element ◽  
Box Beams ◽  
Thin Walled ◽  
Three Dimensional Finite Element

Static and vibration characteristics of thin-walled straight and curved box beams were investigated experimentally. Three different beam configurations were considered for the tests: one straight and two curved box beams. The load was applied at the centroid of the box section for the straight and one curved beam specimens. However, for the other curved specimen, the load was applied eccentrically to investigate its behavior under the additional torsion induced by the eccentricity. Displacements and strains were obtained using linear variable displacement transducer, one-directional and rosette strain gages. The specimens were excited using an impact at their free ends. The time history of strains was obtained to calculate natural frequencies and damping ratios. The experiment results were compared with those obtained from three-dimensional finite element analysis for all cases. The results obtained from implementing tests on the straight specimen were also used to validate an efficient numerical method recently developed by the authors.

scholarly journals Hydrothermal synthesis and structure of a new layered zincophosphate intercalated with 3-methylaminopropylamine cations

2005 ◽  
Vol 70 (4) ◽  
pp. 625-634 ◽  
Author(s):  
Nevenka Rajic ◽  
Natasa Zabukovec-Logar ◽  
Djordje Stojakovic ◽  
Sanja Sajic ◽  
Amalija Golobic ◽  
...  
Keyword(s):  
Activation Energy ◽  
Hydrothermal Synthesis ◽  
Hydrogen Bonds ◽  
Negative Charge ◽  
Membered Ring ◽  
Hydroxyl Groups ◽  
Hydrothermal Crystallization ◽  
Structure Directing Agent

A novel layered zincophosphate (ZnPO?MPA) was prepared by hydrothermal crystallization using 3-methylaminopropylamine (MPA) as a structure-directing agent. The structure consists of macroanion [Zn2P3O8(OH)3]2- layers which are built up of 4-membered ring channels. The channels (of about 3.7 ? diameter) arise through the connection of the neighbouring rings by two oxygen bridges. The negative charge of the layers is compensated by diprotonated MPA molecules which are stacked parallel to the ring channels. ZnPO?MPA is stable up to 300 ?C. At higher temperatures MPA decomposition begins followed by a dehydration, which occurs through condensation of the framework hydroxyl groups. The activation energy of the MPA decomposition is high due to the fact that the layers and MPA cations are held together by strong hydrogen bonds.

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