scholarly journals FEM Based Elasto-Electric Analysis of Elastomers for Pharmaceutical Applications

2021 ◽  
pp. 538-549
Author(s):  
Rumesa Nazeer ◽  
Mehwish Afridi ◽  
. Marvi ◽  
Muhammad Umair Alam ◽  
Badar Ali ◽  
...  
Keyword(s):  
Surface Deformation ◽  
Intermolecular Forces ◽  
Potential Hazard ◽  
Surgical Equipment ◽  
Silicon Rubber ◽  
Maximum Deformation ◽  
Software Analysis ◽  
Pharmaceutical Applications ◽  
External Forces ◽  
Weak Intermolecular Forces

Elastomer materials are very important due to weak intermolecular forces and very low Young's modulus and have high failure strain. Due to these properties, they are used in a large number of applications especially in pharmaceutical industry and medical / surgical equipment etc. Electrostatic discharge on such material is a potential hazard for the operator who is dealing with elastomers.  In the research presented here, a detailed analysis on the elasto-electric analysis of 03x elastomers is analyzed in detail by using Finite Element Method (FEM). A CAD model is generated in accordance with an early research on elasto-electric study of Silicon material. Subsequently FEM based analysis is carried out to study vital electrostatics properties like Surface deformation and surface potential distribution developed on the application of external forces on 03x types of elastomers i.e. Silicon Rubber, Nitrile (NBR) and Poly Vinyl Chloride (PVC). The whole study is carried out in COMSOL multi-physics software. Analysis showed that the electric field developed on the surface of the elastomer is dependent on the deformation on non-linear nature and depends upon the material properties. FEM based results show that Silicon Rubber develops maximum deformation and electric potential of three chosen materials up to 50mm and 3150V respectively. Based on the conducted analysis, Silicon Rubber is widely recommended for its utilization in Pharmaceutical applications requiring electrostatics.

scholarly journals Analysis of surface deformation and driving forces in Lanzhou

2020 ◽  
Vol 12 (1) ◽  
pp. 1127-1145
Author(s):  
Wenhui Wang ◽  
Yi He ◽  
Lifeng Zhang ◽  
Youdong Chen ◽  
Lisha Qiu ◽  
...  
Keyword(s):  
International Development ◽  
Surface Deformation ◽  
Driving Forces ◽  
Influence Factors ◽  
Chinese Government ◽  
Single Factor ◽  
Rapid Urbanization ◽  
Temporal Characteristics ◽  
Maximum Deformation ◽  
Rate Of Increase

AbstractSurface deformation has become an important factor affecting urban development. Lanzhou is an important location in the Belt and Road Initiative, an international development policy implemented by the Chinese government. Because of rapid urbanization in Lanzhou, surface deformation occurs easily. However, the spatial-temporal characteristics of surface deformation and the interaction of driving forces behind surface deformation in Lanzhou are unclear. This paper uses small baseline subset InSAR (SBAS-InSAR) technology to obtain the spatial-temporal characteristics of surface deformation in Lanzhou based on 32 Sentinel-1A data from March 2015 to January 2017. We further employ a geographical detector (geo-detector) to analyze the driving forces (single-factor effects and multifactor interactions) of surface deformation. The results show that the central urban area of Lanzhou was stable, while there was surface deformation around Nanhuan road, Dongfanghong Square, Jiuzhou, Country Garden, Dachaiping, Yujiaping, Lanzhou North Freight Yard, and Liuquan Town. The maximum deformation rate was −26.50 mm year−1, and the maximum rate of increase was 9.80 mm year−1. The influence factors of surface deformation in Lanzhou was a complex superposition relationship among various influencing factors, not a result of the single factor. The interaction between the built-up area and land cover types was the most important factor behind surface deformation in Lanzhou. This paper provides the reference data and scientific foundation for disaster prevention in Lanzhou.

4. Gelification and soapiness

2020 ◽  
pp. 63-90
Author(s):  
Tom McLeish
Keyword(s):  
Brownian Motion ◽  
Self Assembly ◽  
Soft Matter ◽  
Intermolecular Forces ◽  
Two Dimensional ◽  
Important Distinction ◽  
One Dimensional ◽  
The Third ◽  
Self Assembled ◽  
Weak Intermolecular Forces

‘Gelification and soapiness’ looks at the third class of soft matter: ‘self-assembly’. Like the colloids of inks and clays, and the polymers of plastics and rubbers, ‘self-assembled’ soft matter also emerges as a surprising consequence of Brownian motion combined with weak intermolecular forces. Like them, it also leads to explanations of a very rich world of materials and phenomena, such as gels, foams, soaps, and ultimately to many of the structures of biological life. There is an important distinction that needs to be made between one-dimensional and two-dimensional self-assembly.

scholarly journals Fast and accurate quantum Monte Carlo for molecular crystals

2018 ◽  
Vol 115 (8) ◽  
pp. 1724-1729 ◽  
Author(s):  
Andrea Zen ◽  
Jan Gerit Brandenburg ◽  
Jiří Klimeš ◽  
Alexandre Tkatchenko ◽  
Dario Alfè ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Quantum Monte Carlo ◽  
Materials Science ◽  
Computational Cost ◽  
Molecular Crystals ◽  
Intermolecular Forces ◽  
High Accuracy ◽  
Computational Approach ◽  
Large Molecules ◽  
Weak Intermolecular Forces

Computer simulation plays a central role in modern-day materials science. The utility of a given computational approach depends largely on the balance it provides between accuracy and computational cost. Molecular crystals are a class of materials of great technological importance which are challenging for even the most sophisticated ab initio electronic structure theories to accurately describe. This is partly because they are held together by a balance of weak intermolecular forces but also because the primitive cells of molecular crystals are often substantially larger than those of atomic solids. Here, we demonstrate that diffusion quantum Monte Carlo (DMC) delivers subchemical accuracy for a diverse set of molecular crystals at a surprisingly moderate computational cost. As such, we anticipate that DMC can play an important role in understanding and predicting the properties of a large number of molecular crystals, including those built from relatively large molecules which are far beyond reach of other high-accuracy methods.

scholarly journals The 2017 Noneruptive Unrest at the Caldera of Cerro Azul Volcano (Galápagos Islands) Revealed by InSAR Observations and Geodetic Modelling

2019 ◽  
Vol 11 (17) ◽  
pp. 1992 ◽  
Author(s):  
Qian Guo ◽  
Caijun Xu ◽  
Yangmao Wen ◽  
Yang Liu ◽  
Guangyu Xu
Keyword(s):  
Surface Deformation ◽  
Surface Displacement ◽  
Galapagos Islands ◽  
Magma Source ◽  
Deformation Model ◽  
Potential Hazard ◽  
Galápagos Islands ◽  
Peak Displacement ◽  
Extensive Surface ◽  
Lava Lakes

An unrest event occurred at the Cerro Azul volcano, Galápagos Islands, South America, in March 2017, leading to significant surface deformation on the southern Isabela Island, without eruption or surface rupture. We collected single-look complex synthetic aperture radar (SAR) images sensed by the Sentinel-1A satellite, obtaining eight differential interferograms, of which four showed extensive surface displacement during the co-unrest period. Geodetic data indicated that the unrest continued from 18 March to 25 March, reaching a negative peak displacement of −32.9 cm in the caldera and a positive peak displacement of 41.8 cm on the south-east plain in the line-of-sight direction. A joint magma source deformation model, consisting of a Mogi source below the caldera and a sill source south-east of the caldera, was inverted by the Markov chain Monte Carlo method combined with the Metropolis–Hasting algorithm, acquiring the best fit with the four interferograms. The magma transport mechanism of the event was explained by magma overflowing from the compressive Mogi to the tensile sill source, resulting in the observed “∞”-shaped deformation fields. Additionally, we investigated previous events with eruption rifts and lava lakes in 1979, 1998, and 2008, and proposed a potential hazard of tectonic volcanic activity for further volcanic susceptibility research in the Cerro Azul area.

Die Abhängigkeit der Fluoreszenzquantenausbeute von der Anregungswellenlänge bei Carbonylverbindungen des Pyrens

1974 ◽  
Vol 29 (5) ◽  
pp. 804-809
Author(s):  
P. Kröning
Keyword(s):  
Wave Length ◽  
Intermolecular Forces ◽  
Short Wave ◽  
Dilute Solution ◽  
Concentrated Solutions ◽  
Polar Solvents ◽  
Excitation Wave ◽  
Long Wave ◽  
Weak Intermolecular Forces ◽  
Monomer Fluorescence

Abstract Pyrene-3-aldehyde, 3-acetylpyrene and 3-benzoylpyrene show almost no fluorescence in dilute solution in non-polar solvents. In more concentrated solutions, however, a long wave fluorescence is observed, showing the existence of weak intermolecular forces, even in the ground state. In polar solvents, pyrene-3-aldehyde and 3-acetylpyrene exhibit short wave monomer fluorescence whilst 3-benzoylpyrene does not fluoresce. The intensity for both long and short wave fluorescence is dependent upon the excitation wave length and is a maximum for excitation in the weak long wave tail of the first absorption band. Molecules are thought to have a greater absorption in this region if they interact strongly with their polar or polarizable surroundings. Due to the very short singlet lifetime of isolated monomers (τ<C10-10 sec), such molecules have a greater probability of forming a fluorescence state than more weakly interacting ones.

Measurement Method in Model Test of Ice Breaking by Air Cushion Vehicle

2012 ◽  
Vol 204-208 ◽  
pp. 4694-4697
Author(s):  
Zhi Hong Zhang ◽  
Chong Wang ◽  
Jian Nong Gu ◽  
Tao Miao ◽  
Lu Feng Wang ◽  
...  
Keyword(s):  
Surface Deformation ◽  
Measuring System ◽  
Resonance Mechanism ◽  
Maximum Deformation ◽  
Speed Measurement ◽  
Water Resonance ◽  
Air Cushion ◽  
Series Of Experiments ◽  
Air Cushion Vehicle ◽  
Ice Water

A high accuracy non-contact laser displacement measuring system is developed to obtain the surface deformation of the ice-like material. A speed measurement and positioning system is established for the moving air cushion load. The mechanical properties of the ice-like material and the pressure distribution of air cushion load are measured. Under different air cushion load and different speed, a series of experiments of the deformation of ice-like material are carried out in towing channel which the depth of water is variable. The maximum deformation of ice-like material can be caused when air cushion load moves at critical speed, and the ice-water resonance mechanism of ice-breaking by air cushion is revealed, which provides the basis of ice-breaking for practical air cushion vehicle.

Model Experiment of Ice Breaking by Moving Air Cushion Load

2012 ◽  
Vol 170-173 ◽  
pp. 3112-3115
Author(s):  
Bang Bi Sun ◽  
Zhi Hong Zhang ◽  
Chong Wang ◽  
Jian Nong Gu ◽  
Tao Miao ◽  
...  
Keyword(s):  
Surface Deformation ◽  
Similarity Theory ◽  
High Accuracy ◽  
Measuring System ◽  
Positioning System ◽  
Maximum Deformation ◽  
Speed Measurement ◽  
Air Cushion ◽  
Series Of Experiments ◽  
Moving Speed

According to the differential equation of thin elastic vibrating plate and the similarity theory, the similar relationships of corresponding parameters between model and prototype as well as between the ice-like material and the real ice are established. A high accuracy non-contact laser displacement measuring system is developed to obtain the surface deformation of the ice-like material. A speed measurement and positioning system is established for the moving air cushion load. At different moving speed of air cushion load, a series of experiments of the deformation of ice-like material are carried out in towing channel which the depth of water is variable. At critical speed the maximum deformation of ice-like material can be caused, and the theory is derived and analyzed. Research results present the basis of ice-breaking for practical air cushion vehicle (ACV).

Weak Intermolecular Forces, but High Melting Points

2017 ◽  
Vol 70 (5) ◽  
pp. 538 ◽  
Author(s):  
Jiabin Gao ◽  
Djamal Djaidi ◽  
Christopher E. Marjo ◽  
Mohan M. Bhadbhade ◽  
Alison T. Ung ◽  
...  
Keyword(s):  
Molar Mass ◽  
Intermolecular Forces ◽  
High Melting ◽  
High Melting Point ◽  
Enantiomerically Pure ◽  
X Ray ◽  
Drug Molecules ◽  
Poorly Soluble ◽  
Weak Intermolecular Forces

The poorly soluble racemic compound 6,6a,13,13a-tetrahydropentaleno[1,2-b:4,5-b′]diquinoline (4) has an exceptionally high melting point range of 352–354°C despite its low molar mass (308.38) and a structure containing only 40 atoms (38 of which are C and H). Analysis of the X-ray crystal structure and Hirshfeld surface of 4, along with comparison with its isostructural homologue 2, reveals how this occurs in the absence of Pauling-type hydrogen bonding. Excellent complementarity between homochiral molecules of 4 allows formation of enantiomerically pure layers using C–H⋯π, aromatic π⋯π, and C–H⋯N interactions. The alternating layers of opposite handedness are then crosslinked by means of aza-1,3-peri hydrogen interactions. This bifurcated C–H⋯N⋯H–C motif acts as a molecular clip creating a highly rigid network structure. The role of weaker intermolecular forces in influencing the solubility and bioavailability of potential drug molecules is discussed in the context of the popular Lipinski ‘rule of 5’ guidelines.

Non-covalent interactions in the crystallization of the enantiomers of 1,7-dioxaspiro[5.5]undecane (olive fly sex pheromone) by enantiospecific cyclodextrin hosts, hexakis(2,3,6-tri-O-methyl)-α-cyclodextrin and heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin

2001 ◽  
Vol 57 (3) ◽  
pp. 399-409 ◽  
Author(s):  
Stella Makedonopoulou ◽  
Konstantina Yannakopoulou ◽  
Demetrios Mentzafos ◽  
Victor Lamzin ◽  
Alexander Popov ◽  
...  
Keyword(s):  
Sex Pheromone ◽  
Intermolecular Forces ◽  
Racemic Mixture ◽  
Olive Fly ◽  
Non Covalent Interactions ◽  
First Time ◽  
Weak Intermolecular Forces ◽  
Covalent Interactions ◽  
Insight Into

The enantiomers of racemic olive fly sex pheromone 1,7-dioxaspiro[5.5]undecane (1) have been isolated by crystallization with enantiospecific cyclodextrin hosts: (S)-(1) crystallizes with heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin (TMβCD) and (R)-(1) with hexakis(2,3,6-tri-O-methyl)-α-cyclodextrin (TMαCD). The crystal structure of TMβCD/(S)-(1) from synchrotron radiation data at 100 K, determined for the first time, proves that TMβCD crystallizes with only the (S)-enantiomer from the racemic mixture. Comparison with the 100 K structure of TMαCD/(R)-(1) redetermined with synchrotron data has provided insight into the interactions between each of the hosts with the corresponding enantiomeric guests. Owing to the high resolution of the data and the unusually high quality of the crystals, localization of the H atoms has been achieved, a rare accomplishment for cyclodextrin X-ray structures. This made possible, apart from the geometry of the complexes, the detailed description of a five-membered-ring water cluster with very well ordered hydrogen bonding. The enantiospecificity exhibited by the described systems reveals the subtle differences of the weak intermolecular forces involved in the selective binding of the two optical antipodes by the two hosts. The binding geometry in the two complexes is different, but it is effected in both by numerous host–guest C—H...O interactions, resulting from induced fit of the hosts toward each of the enantiomeric guests. In TMαCD/(R)-(1) two of these H...O host–guest distances, directed toward the acetal O atoms defining the chirality of the guest, are much shorter than the rest and also shorter than all the H...O distances in TMβCD/(S)-(1). Moreover, (R)-(1) interacts not only with the enclosing host, but with other hosts in the crystal lattice, in contrast to (S)-(1) in the TMβCD/(S)-(1) complex which is isolated inside channels formed by the host molecules. The above differences are reflected in the much higher binding constant of TMαCD/(R)-(1) compared with that of TMβCD/(S)-(1) (∼6800 and ∼935 M−1, respectively), determined by NMR in aqueous solution, and the ability of TMαCD to selectively precipitate (R)-(1) from racemic (1) in much higher yield than TMβCD precipitates (S)-(1).

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