Temperature dependence of polyhedral cage volumes in clathrate hydrates

2003 ◽  
Vol 81 (1-2) ◽  
pp. 183-189 ◽  
Author(s):  
B C Chakoumakos ◽  
C J Rawn ◽  
A J Rondinone ◽  
L A Stern ◽  
S Circone ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Volume Ratio ◽  
Neutron Powder Diffraction Data ◽  
Structural Formulas ◽  
Equivalent Sphere ◽  
Trimethylene Oxide ◽  
The Mean ◽  
Calorimetric Studies ◽  
Polyhedral Volumes ◽  
The Ideal

The polyhedral cage volumes of structure I (sI) (carbon dioxide, methane, trimethylene oxide) and structure II (sII) (methane–ethane, propane, tetrahydrofuran, trimethylene oxide) hydrates are computed from atomic positions determined from neutron powder-diffraction data. The ideal structural formulas for sI and sII are, respectively, S2L6 · 46H2O and S16L'8 · 136H2O, where S denotes a polyhedral cage with 20 vertices, L a 24-cage, and L' a 28-cage. The space-filling polyhedral cages are defined by the oxygen atoms of the hydrogen-bonded network of water molecules. Collectively, the mean cage volume ratio is 1.91 : 1.43 : 1 for the 28-cage : 24-cage : 20-cage, which correspond to equivalent sphere radii of 4.18, 3.79, and 3.37 Å, respectively. At 100 K, mean polyhedral volumes are 303.8, 227.8, and 158.8 Å3 for the 28-cage, 24-cage, and 20-cage, respectively. In general, the 20-cage volume for a sII is larger than that of a sI, although trimethylene oxide is an exception. The temperature dependence of the cage volumes reveals differences between apparently similar cages with similar occupants. In the case of trimethylene oxide hydrate, which forms both sI and sII, the 20-cages common to both structures contract quite differently. From 220 K, the sII 20-cage exhibits a smooth monotonic reduction in size, whereas the sI 20-cage initially expands upon cooling to 160 K, then contracts more rapidly to 10 K, and overall the sI 20-cage is larger than the sII 20-cage. The volumes of the large cages in both structures contract monotonically with decreasing temperature. These differences reflect reoriented motion of the trimethyelene oxide molecule in the 24-cage of sI, consistent with previous spectroscopic and calorimetric studies. For the 20-cages in methane hydrate (sI) and a mixed methane–ethane hydrate (sII), both containing methane as the guest molecule, the temperature dependence of the 20-cage volume in sII is much less than that in sI, but sII is overall larger in volume. PACS Nos.: 82.75, 61.66H, 65.40D, 61.12

Temperature Dependences in the O + OH → O2 + H Reaction. Quasiclassical Trajectory Calculation

1993 ◽  
Vol 58 (2) ◽  
pp. 234-243 ◽  
Author(s):  
Viliam Klimo ◽  
Martina Bittererová ◽  
Stanislav Biskupič ◽  
Ján Urban ◽  
Miroslav Micov
Keyword(s):  
Temperature Dependence ◽  
Energy Surface ◽  
Analytical Form ◽  
Mean Values ◽  
Quantum Numbers ◽  
Mean Lifetime ◽  
Temperature Dependences ◽  
Quasiclassical Trajectory Calculation ◽  
The Mean ◽  
Combustion Processes

The reaction O + OH → O2 + H in conditions of combustion of hydrocarbons and polymers was modelled by using the method of quasiclassical trajectories. The potential energy surface was determined by the multiconfiguration interaction method and fitted with the analytical form of the extended LEPS function. Attention was paid to the mean values of the vibrational and rotational quantum numbers of O2 molecules and their temperature dependence. The temperature dependence of the mean lifetime of the OOH collision complex was also examined. The calculated rate constants were analyzed and compared with the experimental data over the temperature region of the combustion processes.

Happiness, Virtue, and Political Society

2018 ◽  
Author(s):  
T. M. Rudavsky
Keyword(s):  
Moral Philosophy ◽  
Political Behavior ◽  
Political Society ◽  
Ideal Model ◽  
The Road ◽  
Doctrine Of The Mean ◽  
The Mean ◽  
The Ideal ◽  
Divine Law

Chapter 9 is concerned with social and political behavior. Even in the context of moral philosophy, Jewish philosophers discuss issues within the wider context of a rational scientific perspective. This chapter begins with specific moral codes developed by Jewish thinkers, focusing in particular upon the works of Ibn Gabirol, Baḥya ibn Paquda, Maimonides, and Crescas. Can there be ethical dictates independent of the commandments? The rabbis already worried whether there existed a domain of “right behavior” that pre-dates, or exists independently of, divine commandment. Does Aristotle’s doctrine of the mean apply to divine law? Furthermore, can all humans achieve intellectual perfection? Is the road the same, and open, to all? And is there only one road to ultimate felicity, or are there many routes? The chapter ends with a discussion of whether human felicity can be achieved in this life, and whether the prophet best represents the ideal model for such achievement.

scholarly journals Impact of a Smart-Ring-Based Feedback System on the Quality of Chest Compressions in Adult Cardiac Arrest: A Randomized Preliminary Study

2021 ◽  
Vol 18 (10) ◽  
pp. 5408
Author(s):  
Chiwon Ahn ◽  
Seungjae Lee ◽  
Jongshill Lee ◽  
Jaehoon Oh ◽  
Yeongtak Song ◽  
...  
Keyword(s):  
Primary Outcome ◽  
Feedback System ◽  
Controlled Study ◽  
Feedback Group ◽  
Compression Depth ◽  
System Usability Scale ◽  
The Mean ◽  
Preliminary Study ◽  
The Ideal

This study aimed to assess the effectiveness of a novel chest compression (CC) smart-ring-based feedback system in a manikin simulation. In this randomized, crossover, controlled study, we evaluated the effect of smart-ring CC feedback on cardiopulmonary resuscitation (CPR). The learnability and usability of the tool were evaluated with the System Usability Scale (SUS). Participants were divided into two groups and each performed CCs with and without feedback 2 weeks apart, using different orders. The primary outcome was compression depth; the proportion of accurate-depth (5–6 cm) CCs, CC rate, and the proportion of complete CCs (≤1 cm of residual leaning) were assessed additionally. The feedback group and the non-feedback group showed significant differences in compression depth (52.1 (46.3–54.8) vs. 47.1 (40.5–49.9) mm, p = 0.021). The proportion of accurate-depth CCs was significantly higher in the interventional than in the control condition (88.7 (30.0–99.1) vs. 22.6 (0.0–58.5%), p = 0.033). The mean SUS score was 83.9 ± 8.7 points. The acceptability ranges were ‘acceptable’, and the adjective rating was ‘excellent’. CCs with smart-ring feedback could help achieve the ideal range of depth during CPR. The smart-ring may be a valuable source of CPR feedback.

35Cl NQR Spectroscopy on Salts and Molecular Compounds of Trichloroacetic Acid

1986 ◽  
Vol 41 (1-2) ◽  
pp. 215-224 ◽  
Author(s):  
Winfried Fichtner ◽  
Axel Markworth ◽  
Norbert Weiden ◽  
Alarich Weiss
Keyword(s):  
Frequency Shift ◽  
Temperature Dependence ◽  
Linear Relation ◽  
Trichloroacetic Acid ◽  
Mean Frequency ◽  
35Cl Nqr ◽  
The Mean ◽  
Molecular Compounds

The temperature dependence of salts M(1)H(Cl3CCOO)2 and molecular compounds of trichloroacetic acid with amines and benzaldehydes, TCA · X, was studied,The data fit rather well to the known dependence of the mean frequency shift Δ <v(35Cl)> on the pkadifference of X with respect to TCA. A linear relation is observed between the bleaching out temperature Tb of the 35Cl NQR lines and Δ <v(35Cl)> for M(1)H(Cl3CCOO)2 and for TCA · X, X = benzaldehydes.

scholarly journals Temperature dependence of the mean magnon collision time in a spin Seebeck device

2021 ◽  
pp. 168289
Author(s):  
Vittorio Basso ◽  
Alessandro Sola ◽  
Patrizio Ansalone ◽  
Michaela Kuepferling
Keyword(s):  
Temperature Dependence ◽  
Collision Time ◽  
The Mean

scholarly journals The importance of pial blood supply to the development of peritumoral brain edema in meningiomas

1997 ◽  
Vol 2 (4) ◽  
pp. E6 ◽  
Author(s):  
Michael Bitzer ◽  
Lars Wöckel ◽  
Andreas R. Luft ◽  
Ajay K. Wakhloo ◽  
Dirk Petersen ◽  
...  
Keyword(s):  
Brain Edema ◽  
Blood Supply ◽  
Tumor Size ◽  
Tumor Volume ◽  
Volume Ratio ◽  
Total Tumor Volume ◽  
Pial Vessels ◽  
Peritumoral Brain Edema ◽  
Tumor Region ◽  
The Mean

The authors studied the pial and dural blood supplies in 74 intracranial meningiomas and quantified their associated peritumoral brain edema (PTBE). The extent and localization of pial blush in relation to the total tumor volume were determined angiographically. The amount of edema and tumor size were calculated using computerized tomography. The edema-tumor volume ratio was defined as Edema Index (EI). There were 49 meningiomas with PTBE; of those tumors, 46 were supplied by pial vessels, and three were supplied exclusively by dural vessels. Tumors without PTBE showed no pial blush. The mean EI in meningiomas with pial blush was significantly larger (EI = 3.0) than in meningiomas without pial supply (EI = 1.1; p < 0.0001). Meningiomas in which 10% of the whole tumor volume was supplied by pial vessels had only a small mean EI of 2.2, whereas tumors with pial blood supply greater than or equal to 20% had a mean EI of 3.3 (p < 0.026). In 69.9% of cases with pial blood supply, major portions of the edema were located adjacent to the tumor region supplied by pial vessels. Edema index differences among tumors of different subgroups, as defined by size or histology, were significantly related to the pial supply in each subset. Thus, pial blood supply may be causative for the development of PTBE in meningiomas.

TO ASSESS THE IDEAL TIME OF LAPAROSCOPIC CHOLECYSTECTOMY AFTER ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY IN CASES OF CHOLELITHIASIS WITH CHOLEDOCHOLITHIASIS

2021 ◽  
Vol 5 (4) ◽  
Author(s):  
Dhirendra Godara ◽  
Vineet Choudhary ◽  
Nitish Soni
Keyword(s):  
Laparoscopic Cholecystectomy ◽  
Endoscopic Retrograde Cholangiopancreatography ◽  
Medical Sciences ◽  
Early Recovery ◽  
Endoscopic Retrograde ◽  
The Mean ◽  
Group 2 ◽  
Late Group ◽  
Group 1 ◽  
The Ideal

Background: Aims of this study was assess the ideal time of laparoscopic cholecystectomy after endoscopic retrograde cholangiopancreatography in cases of cholelithiasis with Choledocholthiasis Methods: The present study was carried out on 150 patients admitted in Department of General surgery National Institute of Medical Sciences and Research, Jaipur, diagnosed with cholelithiasis along with choledocholithiasis  from 1stJanuary 2019 to 30thJune, 2020. Results: In group 1 out of 75 patients 7 patients developed complications in post operative period compared to 35 patients out of 75 patients developed complications in group 2. The The mean hospital stay (in day) in group 1 patients was 2.26, median 2 and the mean of group 2 was 5.26, median 5. Conclusion: To conclude in our study there has been found significant advantage of early laparoscopic cholecystecomy following ERCP over the late group to minimize complications and promote early recovery of the patients. Keywords: ERCP, Cholecystectomy, Endoscopic retrograde cholangiopancreatography

scholarly journals Stent technique for endoscopic dacryocystorhinostomy – Our expertise

2016 ◽  
Vol 6 (21) ◽  
pp. 23-27
Author(s):  
Vlad Budu ◽  
Tatiana Decuseara ◽  
Bogdan Mocanu ◽  
Raluca Baican ◽  
Mihai Tusaliu ◽  
...  
Keyword(s):  
Success Rate ◽  
Lacrimal Sac ◽  
Lacrimal Duct ◽  
Bottom Edge ◽  
Duct Obstruction ◽  
Endoscopic Dacryocystorhinostomy ◽  
Lacrimal Apparatus ◽  
The Mean ◽  
Surgery Department ◽  
The Ideal

Abstract BACKGROUND. Endoscopic dacryocystorhinostomy is known to be the ideal treatment for saccal and postsaccal stenosis of the lacrimal apparatus. Following this surgery, an important inconvenient would be the stenosis of the created ostium with consecutive epiphora. MATERIAL AND METHODS. 20 patients with chronic unilateral lacrimal duct obstruction were operated in “Prof. Dr. D. Hociota” Institute of Phono-Audiology and Functional ENT Surgery, Department I, between January 2015 and July 2015. After creating the dacryocystorhinostoma, a stent was inserted transnasally to the bottom edge of the lacrimal sac and positioned to the bony margin of the ostium. Stents used varied in size from 1 to 3 mm in diameter. We followed-up our patients at 2 weeks and 1, 3, 6 months, assessing the symptoms of the lacrimal apparatus, especially the epiphora. RESULTS. The mean age of patients varied between 31 and 65. Most of our patients were women (n=14). In a total number of 16 patients epiphora disappeared, it decreased in 2 patients, and persisted in 2 patients. There were two patients with no changes who have spontaneously eliminated the stent 2 or 3 days after the surgery. The most widely used stent size was 3 mm diameter, with a success rate of 90%. CONCLUSION. The endoscopic approach may be an effective procedure in patients with pathologies of the lacrimal apparatus. In order to achieve an efficient result, both a preoperative rigorous preparation and also postoperative medical care are necessary. In conclusion, ostium stenting represents a better way to ensure a longer period of maintaining the permeability of the lacrimal apparatus.

scholarly journals CO2 Adsorption in Metal-Organic Framework Mg-MOF-74: Effects of Inter-Crystalline Space

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2274
Author(s):  
Siddharth Gautam ◽  
David Cole
Keyword(s):  
Metal Organic Framework ◽  
Co2 Storage ◽  
Volume Ratio ◽  
Chem Phys ◽  
Crystallite Sizes ◽  
Metal Organic ◽  
Adsorption Of Co2 ◽  
Gcmc Simulations ◽  
Grand Canonical ◽  
The Ideal

Metal-Organic Frameworks (MOF) have been identified as highly efficient nanoporous adsorbents for CO2 storage. In particular, Mg-MOF-74 has been shown to promise exceptionally high CO2 sorption. Although several studies have reported adsorption isotherms of CO2 in Mg-MOF-74, the effect of inter-crystalline spacing in Mg-MOF-74 on the sorption of CO2 has not been addressed. These effects have been shown to be profound for a quadrupolar molecule like CO2 in the case of silicalite (Phys. Chem. Chem. Phys. 22 (2020) 13951). Here, we report the effects of inter-crystalline spacing on the adsorption of CO2 in Mg-MOF-74, studied using grand canonical Monte Carlo (GCMC) simulations. The inter-crystalline spacing is found to enhance adsorption at the crystallite surfaces. Larger inter-crystalline spacing up to twice the kinetic diameter of CO2 results in higher adsorption and larger crystallite sizes suppress adsorption. Magnitudes of the inter-crystalline space relative to the kinetic diameter of the adsorbed fluid and the surface to volume ratio of the adsorbent crystallites are found to be important factors determining the adsorption amounts. The results of this study suggest that the ideal Mg-MOF-74 sample for CO2 storage applications should have smaller crystallites separated from each other with an inter-crystalline space of approximately twice the kinetic diameter of CO2.

scholarly journals A Comparison of the Mean-Value and Initial-Value Solutions of the Ideal Resonance Problem with an Application in Rigid-Body Mechanics

1974 ◽  
Vol 62 ◽  
pp. 209-209
Author(s):  
A. H. Jupp
Keyword(s):  
Elliptic Functions ◽  
Mean Value ◽  
Resonance Problem ◽  
Ideal Resonance ◽  
Deep Circulation ◽  
Ideal Resonance Problem ◽  
Rigid Body Mechanics ◽  
The Mean ◽  
Mean Elements ◽  
The Ideal

A solution of the ideal resonance problem has already been exhibited (Jupp, 1972) explicitly in terms of the ‘mean’ elements; to second order in the small parameter in the case of libration, and to first order in the case of deep circulation. Both representations possess a singularity when the ‘mean’ modulus of the Jacobi elliptic functions is unity; this corresponds to motions on or close to the separatrix of the phase plane of the dynamical system.

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