Long-time Performance of Bottles Made of PET Blended with Various Concentrations of Oxygen Scavenger Additive Stored at Different Temperatures

2017 ◽  
Vol 30 (1-2) ◽  
pp. 45-58 ◽  
Author(s):  
Sven Sängerlaub ◽  
Kajetan Müller
Keyword(s):  
Oxygen Scavenger ◽  
Time Performance ◽  
Different Temperatures ◽  
Long Time

scholarly journals Impact of Deuteration and Temperature on Furan Ring Dynamics

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2889
Author(s):  
Przemyslaw Dopieralski ◽  
Iryna V. Omelchenko ◽  
Zdzislaw Latajka
Keyword(s):  
Conformational Changes ◽  
Furan Ring ◽  
Computational Studies ◽  
Significant Progress ◽  
Dynamic Simulations ◽  
Cyclic Molecules ◽  
Ring Dynamics ◽  
Different Temperatures ◽  
Long Time ◽  
Shape And Size

Despite significant progress in conformational analysis of cyclic molecules, the number of computational studies is still limited while most of that available in the literature data have been obtained long time ago with outdated methods. In present research, we have studied temperature driven conformational changes of the furan ring at three different temperatures. Additionally, the effect of deuteration on the ring dynamics is discussed; in addition, the aromaticity indices following the Bird and HOMA schemes are computed along all trajectories. Our ab initio molecular dynamic simulations revealed that deuteration has changed the furan ring dynamics and the obvious consequences; in addition, the shape and size of molecule are expected to be different.

Mechanical and tribological properties of ice-bonded abrasive polishing tools

2017 ◽  
Vol 233 (1) ◽  
pp. 132-144 ◽  
Author(s):  
S Rambabu ◽  
N Ramesh Babu
Keyword(s):  
Wear Rate ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Melting Rate ◽  
Wear Behaviour ◽  
Mechanical And Tribological Properties ◽  
Different Temperatures ◽  
Long Time ◽  
Polishing Tool ◽  
Hardness Coefficient

This article covers the efforts on characterising ice-bonded abrasive polishing tool in terms of the mechanical and tribological properties such as hardness, coefficient of friction, and wear rate. These studies were attempted on the tools prepared at different temperatures ranging from −10 °C to 0 °C with a view to identify the condition suitable to prepare ice-bonded abrasive polishing tool for effective polishing of Ti–6Al–4V alloy specimen. It also presents the methods adopted to determine various properties of ice-bonded abrasive polishing tool. Hardness was estimated from the measured penetration depth of cone shape indenter into the tool, coefficient of friction was determined from the change in power drawn by the motor rotating the tool mould, and wear behaviour of tool was assessed from the melting rate of the tool determined from the change in height of ice-bonded abrasive polishing tool at different stages of polishing. From the results of this study, it is clear that ice-bonded abrasive polishing tool prepared at −4 °C has possessed sufficient hardness, coefficient of friction, and reasonable wear rate suitable for polishing of Ti–6Al–4V specimens. This article also covers the details of low-temperature coolant supply unit developed to prepare the ice-bonded abrasive polishing tool at any desired temperature between 0 °C and −40 °C and thus to maintain it for a long time. Polishing studies with such ice-bonded abrasive polishing tool showed 72% improvement in finish after 90 min of polishing of Ti–6Al–4V specimen with tool, prepared at −4 °C.

scholarly journals Long-time performance of a stainless steel crossflow filter with simulated Hanford tank waste

2015 ◽  
Vol 102 ◽  
pp. 69-79 ◽  
Author(s):  
Philip P. Schonewill ◽  
Richard C. Daniel ◽  
Rick W. Shimskey ◽  
Carolyn A. Burns ◽  
Justin M. Billing ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Time Performance ◽  
Long Time ◽  
Tank Waste

scholarly journals Heat Exchanger for Bio-Digester under Thermophilic Range

2019 ◽  
Vol 5 ◽  
pp. 79-88
Author(s):  
Prajwal Sapkota ◽  
Laxman Poudel
Keyword(s):  
Heat Exchanger ◽  
Anaerobic Digestion ◽  
Heat Exchangers ◽  
Heating System ◽  
Gas Production ◽  
Cow Dung ◽  
Digestion Rate ◽  
Digestion Process ◽  
Different Temperatures ◽  
Long Time

Bio-gas has been one of the sources of renewable energy and has been used from long time. It is produced by the anaerobic digestion or decomposition of organic compounds and has different process. The digestion process is carried out by bacteria present in the waste and it is highly dependent on the bacteria which work differently on different temperatures. The rate of anaerobic digestion is highest at hemophilic temperature (55°C). Similarly, it is moderate at mesophilic temperature (35°C) and is lowest at psychrophilic (below 20°C). Thus, to attain the highest digestion rate a thermophilic heating system has beend eveloped. The heating system uses five heat exchangers to heat the influent at digester which is of 35m3 volume, to maintain temperature at 56°C. The volume of bio-gas production from this system which uses cow dung as digestingmaterial is about 28 m3 per day.

scholarly journals 14C Dating of Fire-Damaged Mortars from Medieval Finland

Radiocarbon ◽  
2012 ◽  
Vol 54 (3-4) ◽  
pp. 915-931 ◽  
Author(s):  
Alf Lindroos ◽  
Lior Regev ◽  
Markku Oinonen ◽  
Åsa Ringbom ◽  
Jan Heinemeier
Keyword(s):  
14C Dating ◽  
Carbon And Oxygen Isotopes ◽  
Fire Event ◽  
Oxygen Isotope Ratios ◽  
Hydrolysis Process ◽  
Carbon And Oxygen Isotope ◽  
Different Temperatures ◽  
Long Time ◽  
Original Construction ◽  
Soluble Carbonate

This study focuses on radiocarbon dating of mortars that have withstood city fires and display visible fire damage effects. Some fire-damaged and undamaged original Medieval mortars from the same site have also been tested. The mortars were heated at different temperatures and then analyzed using the same preparation procedures as in 14C dating of mortars to see what kind of changes the heating would introduce to the mineralogy, chemistry, and the carbon and oxygen isotope ratios. We found that decarbonation during heating starts at ∼600 ° and recarbonation starts as soon as the temperature drops. Already after a few days, most of the lost CO2 has been replaced with atmospheric CO2. The renewed carbonates are readily soluble in the acid hydrolysis process and their carbon and oxygen isotopes have a light signature. Fire-damaged historical mortars display the same features. If a long time has elapsed between hardening of the original mortar and the fire, the new carbonates have 14C concentrations that point to the fire event rather than to the building event. In several cases, the fire-damaged mortars have an easily soluble carbonate fraction with a 14C age that could be related to a major fire event, but still most of the soluble carbonate yields a 14C age that seems like a reasonable age for the original construction.

Molecular dynamics study of mesophase transitions upon annealing of imidazolium-based ionic liquids with long-alkyl chains

2018 ◽  
Vol 20 (15) ◽  
pp. 9796-9805 ◽  
Author(s):  
Hailong Peng ◽  
Momoji Kubo ◽  
Hayato Shiba
Keyword(s):  
Molecular Dynamics ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Alkyl Chains ◽  
Different Temperatures ◽  
Long Time

The isotropic to mesophase transition upon the long-time annealing of a 1-dodecyl-3-methylimidazolium hexafluorophosphate ionic liquid at different temperatures is illustrated.

The longevity of the fasting bed-bug (C. lectularius L.) under experimental conditions and particularly in relation to the saturation deficiency law of water-loss

Parasitology ◽  
1940 ◽  
Vol 32 (3) ◽  
pp. 239-270 ◽  
Author(s):  
C. G. Johnson
Keyword(s):  
Water Loss ◽  
Climatic Factors ◽  
Survival Times ◽  
Bed Bugs ◽  
Experimental Conditions ◽  
Unmated Female ◽  
Saturation Deficit ◽  
Hyperbolic Relation ◽  
Different Temperatures ◽  
Long Time

1. With unfed 1st instars the relation between mean length of life and saturation deficit at constant temperatures between 7 and 15° C. at relative humidities between 7 and 90% is hyperbolic. The relationship becomes more linear at higher temperatures.At constant saturation deficits insects live longer at 15° C. than at lower temperatures. Longevity also decreases with rise of temperature above approximately 15° C.2. In general, the longevity curves, except for those at temperatures below 15° C., bear a very similar relation to saturation deficit and to each other as the reciprocal curves for rate of water-loss at the different temperatures.The influence of climatic factors on longevity at constant temperatures is discussed at length and it is concluded that over much of the temperature and humidity range survival time is limited by water-loss. At the higher humidities it is thought that either food, or perhaps an excessive accumulation of water within the insect, limits survival and causes a departure from the hyperbolic relation of longevity to saturation deficit.3. The effects on longevity of a single meal are discussed. The principal effect of a blood meal is to increase the time of survival. But the factors which limit survival at different humidities appear to be the same as with unfed bugs, except at high humidities below about 15° C.4.Mellanby's data on the rate of water-loss from fasting adult bed-bugs is analysed. It is found that the rate of water-loss is directly proportional to saturation deficit at constant temperatures between 8 and 37° C. and between 0 and 90% r.h. Although the rate may always be directly proportional to saturation deficit, the expression is not always constant.Rate = K + b (saturation deficit), where K varies with temperature and b remains constant.5. Longevity in relation to host blood is discussed. Rabbit blood appears to be slightly less favourable to survival than human blood.6. If bugs are allowed to feed to repletion, longevity is not correlated with the size of the meal, nor with the weight of the unfed insect.Virgin females live longer than mated ones, but no effects of mating on survival were noticed with males. Mated males tend to outlive mated females except at very low temperatures: virgin females live longer than unmated males.7. The results of other workers and the possible causes of some discrepancies are discussed.8. The maximum survival times of bugs are listed. Adults and 5th instars live longer than other stages. In a house which has remained empty for a long time it is probable that 5th instars and adults, particularly unmated female adults, would predominate in the population.The longest observed survival was between 562 and 572 days.

Reaction Kinetics at a Fluctuating Surface: Proton Exchange in Proteins

1994 ◽  
Vol 366 ◽  
Author(s):  
T. Gregory Dewey
Keyword(s):  
Fractal Model ◽  
Proton Exchange ◽  
Scaling Exponent ◽  
Fractal Surface ◽  
Free Peptide ◽  
Aqueous Solvent ◽  
Different Temperatures ◽  
Long Time ◽  
Surface Dimension ◽  
Peptide Exchange

ABSTRACTExperimental data for the exchange of protons between proteins and the aqueous solvent is re-examined using a fractal model. The fraction of protons unexchanged from the protein, f is seen to follow a stretched exponential, at long times. For the protein, lysozyme, data over a range of temperatures were considered and accurate fits were obtained with a single, unadjusted scaling exponent, α. The time constant, τ, followed an Arrhenius law and gave an activation energy comparable to that obtained for free peptide exchange. A model is proposed where proton exchange occurs as a result of solvent reacting at the fractal surface of the protein. The protein itself is not treated as static but has units that diffuse to the surface. The diffusion of these units in the long time domain is assumed to be classical. In this model the scaling exponent, α, is related to the spectral dimension of the system. Treating the problem as a reaction of the type A+B→C in a confined region, the exponent is given by: α = (3 − ds)/4 where dS/4 is the fractal surface dimension of the protein. Using the value of 2.17 previously established for the surface dimension of lysozyme, data at 6 different temperatures could be fit with the corresponding α of 0.21. These results show that the fractal structure of a protein can influence difflusional processes of small molecules associating with the protein.

scholarly journals Experimental and Numerical Method for the Analysis of Warm Titanium Sheet Stamping of an Automotive Component

2015 ◽  
Vol 2015 ◽  
pp. 1-10
Author(s):  
Antonio Fiorentino ◽  
Elisabetta Ceretti ◽  
Claudio Giardini
Keyword(s):  
Product Design ◽  
Numerical Models ◽  
Experimental Tests ◽  
Fundamental Aspect ◽  
Automotive Component ◽  
Knowledge Based ◽  
Sheet Stamping ◽  
Different Temperatures ◽  
Long Time ◽  
Product Design Process

Product design involves many aspects as geometry and material or mechanical requirements that have to be chosen on the base of the part requirements. Manufacturing process is the link between them representing a fundamental aspect of the product design process. Designers and technicians have a consolidated set of tools and knowledge based on long time experience, but the request of more new performing products characterized by more complex geometries or harder to form materials as Titanium alloys stimulated the use of numerical models. They allow us to study the product feasibility but they require reliable inputs for their development and validation. The present research focuses on sheet stamping processes and proposes a methodology that uses the Nakazima test to characterize the formability of the material and to develop and validate the model. In particular, the method is applied to cold (20°C) and warm (300°C) stamping of a complex automotive component made of CP Titanium. After characterizing the material and validating the model at the different temperatures, the stamping process is studied and results are compared. In particular, this approach allowed joining the experimental tests required to develop and validate the model, therefore reducing the resources required for the product design.

scholarly journals Damped Oscillations of the Energy of a Bosonic Bath due to Spectral Gaps and Special Initial Correlations

2018 ◽  
Vol 25 (03) ◽  
pp. 1850011 ◽  
Author(s):  
Filippo Giraldi
Keyword(s):  
Open System ◽  
Spectral Gap ◽  
Initial Conditions ◽  
Low Frequency ◽  
Power Laws ◽  
Spectral Gaps ◽  
Damped Oscillations ◽  
Different Temperatures ◽  
Long Time ◽  
The One

The energy of the bosonic bath and the flow of quantum information in local dephasing channels are studied over short and long times in case the distribution of frequency modes of the bosonic bath exhibits a low-frequency gap. The initial conditions consist in special correlations between the qubit and the bosonic bath or are factorized, and involve thermal states of the whole system or of the bath. The low-frequency gap generates damped oscillations of the bath energy around the asymptotic value, for the correlated initial conditions, and induces the open system to alternately loose and gain information, for the factorized initial configurations. The long-time oscillations of the bath energy become regular and the frequency of the oscillations coincides with the upper cut-off frequency of the spectral gap. Regular long-time sequences of intervals are found over which the bath energy increases (decreases), for the correlated initial conditions, and information is lost (gained) by the open system, for the factorized initial configurations, even at different temperatures. This relation is reversed, if compared to the one obtained without the low-frequency gap, and can fail if the spectral density is tailored near the spectral gap according to power laws with odd natural powers.

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