Kinetic approach to the mineral reaction processes during hydrothermal treatment of a saponitic clay

Clay Minerals ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 409-421 ◽  
Author(s):  
J. Cuevas ◽  
A. Garralon ◽  
S. Ramirez ◽  
S. Leguey
Keyword(s):  
Exchange Capacity ◽  
Bet Surface Area ◽  
Time Intervals ◽  
Mineral Contents ◽  
Mineral Reaction ◽  
Hydrothermal Experiments ◽  
Time Period ◽  
One Year ◽  
Short Time ◽  
Reaction Processes

AbstractIn the course of hydrothermal experiments with a saponitic clay, evidence for the dissolution of the accessory sepiolite and the formation of smectite has been detected above 120°C Hydrothermal reactions with a clay to water ratio of 1:3 were performed at temperatures of 60, 90, 120, 175 and 200°C with time intervals of one month to one year.The BET surface area and cation exchange capacity (CEC) are correlated with the sepiolite and the smectite content determined from XRD data. These relations have been used to recalculate the time dependence of the mineral contents in the time/temperature conditions of the experiments. The Ea values obtained for sepiolite dissolution (7-18 kcal/mol) or smectite formation (4.8-5 kcal/mol) indicate that sepiolite dissolution controls the rate of the process. Both results fit an apparent firstorder reaction and the system seems to evolve to a stable mineral composition in a short time period, ranging from one to 10 years as temperature decreases.

scholarly journals Stability Analysis of Bitemarks in Different Conditions of Time and Temperature and Its Reliability as Evidence in Criminal Investigations

2019 ◽  
Vol 30 (3) ◽  
pp. 295-302
Author(s):  
Laís Gomes de Araújo ◽  
Tamara Soledad Frontanilla Recalde ◽  
Victor Jacometti ◽  
Paula Barreto Costa ◽  
Ricardo Henrique Alves da Silva
Keyword(s):  
Significant Influence ◽  
Storage Temperature ◽  
Time Intervals ◽  
Criminal Investigations ◽  
Bite Marks ◽  
Anterior Teeth ◽  
Time Period ◽  
The Stability ◽  
Short Time ◽  
Plaster Models

Abstract The objective of this study was to evaluate the stability of bite marks in foods in different conditions of time and temperature and their reliability as evidenced in criminal investigations. Sampling came from 20 subjects, who were instructed to bite five pieces of cheese and five pieces of chocolate. Bites were produced by the anterior teeth, from canine to canine, and the volunteers had their dental arches molded to obtain plaster models that were used for later comparison. The samples produced by each participant were stored and analyzed according to the temperature (room and refrigerator) and time period (immediately after, three days, seven days). The linear model with mixed effects using R Core Team and SAS Statistical Software were used for the statistical analysis. The results of this study reveal that the storage temperature of these materials does not exert a significant influence. Both chocolate and cheese showed better results when measurements were made shortly after, however the chocolate showed to be more stable in longer periods of time. By means of this study, it was possible to demonstrate that the storage temperature does not exert a significant influence. However, the bite marks found in foods with greater dimensional stability and short time intervals, are more reliable and allow their use as evidence in criminal investigations. Still, due to the limitations presented, we recommend its use for the exclusion of possible suspects and not for the suspects identification.

scholarly journals Leaching pattern of phosphate glass fertilizers with different compositions under Soxhlet distillation conditions

Cerâmica ◽  
2020 ◽  
Vol 66 (379) ◽  
pp. 250-255
Author(s):  
B. Mandal ◽  
G. Hazra ◽  
G. K. Ghosh ◽  
T. Das
Keyword(s):  
Weight Loss ◽  
Ionic Radius ◽  
Glass Structure ◽  
Bet Surface Area ◽  
Distilled Water ◽  
Time Intervals ◽  
Time Period ◽  
Leachate Solution ◽  
Ionic Size ◽  
Leaching Pattern

Abstract Glass fertilizers in the phosphate systems were melted at 900-950 °C with a soaking period of 1 h. Leaching study of these glasses with a maximum time period of 300 h was conducted under Soxhlet distillation condition with distilled water. Weight loss and the leach rates of the glass fertilizer samples were calculated from BET surface area measurements. They were in the range of 6.3x10-3 to 2.3x10-3 g.m-2.h-1 at 90 °C. The effect of different modifier ions like Na+, Fe3+, Mg2+, Ca2+, and K+ in the basic phosphate networks on melting and time of melting has been found to be evident. The pH determination ranging from 4.80 up to 7.50 of the leachate solution at ambient temperature under varying time intervals showed interesting and regular variations. The leaching study of such glasses under Soxhlet condition showed Ca2+, Mg2+, and K+ to be good candidates as modifier towards faster leaching. The findings have been corroborated in terms of ionic size, ionic radius, and hence the ionic potential of the modifier ions incorporated into the glass structure. The application of glass fertilizers was made on kharif paddy.

World Economy: Prospects and Barriers for Recovery

2012 ◽  
pp. 61-83 ◽  
Author(s):  
M. Ershov
Keyword(s):  
World Economy ◽  
Western World ◽  
Short Time Period ◽  
Market Segments ◽  
Junk Bonds ◽  
The Past ◽  
Time Period ◽  
The Us ◽  
Global Liquidity ◽  
Short Time

According to the latest forecasts, it will take 10 years for the world economy to get back to “decent shape”. Some more critical estimates suggest that the whole western world will have a “colossal mess” within the next 5–10 years. Regulators of some major countries significantly and over a short time‑period changed their forecasts for the worse which means that uncertainty in the outlook for the future persists. Indeed, the intensive anti‑crisis measures have reduced the severity of the past problems, however the problems themselves have not disappeared. Moreover, some of them have become more intense — the eurocrisis, excessive debts, global liquidity glut against the backdrop of its deficit in some of market segments. As was the case prior to the crisis, derivatives and high‑risk operations with “junk” bonds grow; budget problems — “fiscal cliff” in the US — and other problems worsen. All of the above forces the regulators to take unprecedented (in their scope and nature) steps. Will they be able to tackle the problems which emerge?

Proposal of PV Output Estimate Method in Short Time Intervals

2016 ◽  
Vol 136 (12) ◽  
pp. 891-897 ◽  
Author(s):  
Katsuhiro Matsuda ◽  
Kazuhiro Misawa ◽  
Hirotaka Takahashi ◽  
Kenta Furukawa ◽  
Satoshi Uemura
Keyword(s):  
Time Intervals ◽  
Estimate Method ◽  
Short Time

EVALUATION OF SHORT TIME INTERVALS IN NORMAL AGING AND LATE-LIFE DEPRESSIONS

2020 ◽  
pp. 54-69
Author(s):  
Elena Yu. Balashova ◽  
◽  
Lika I. Mikeladze ◽  
Elena K. Kozlova ◽  
◽  
...  
Keyword(s):  
Late Life ◽  
Normal Aging ◽  
Time Intervals ◽  
Short Time

Effect of short-term use of oral contraceptive pills on intraocular pressure

2020 ◽  
Vol 35 (3) ◽  
Author(s):  
Tayyaba Gul Malik ◽  
Hina Nadeem ◽  
Eiman Ayesha ◽  
Rabail Alam
Keyword(s):  
Oral Contraceptive ◽  
Childbearing Age ◽  
Short Term ◽  
Oral Contraceptive Pills ◽  
Contraceptive Pills ◽  
Time Period ◽  
Significant Difference ◽  
Group A ◽  
Group B ◽  
Short Time

Objective: To study the effect of short-term use of oral contraceptive pills on intra-ocular pressures of women of childbearing age.   Methods: It was a comparative observational study, conducted at Arif memorial teaching hospital and Allied hospital Faisalabad for a period of six months. Hundred female subjects were divided into two groups of 50 each. Group A, included females, who had been taking oral contraceptive pills (OCP) for more than 6 months and less than 36 months. Group B, included 50 age-matched controls, who had never used OCP. Ophthalmic and systemic history was taken. Careful Slit lamp examination was performed and intraocular pressures (IOP) were measured using Goldman Applanation tonometer. Fundus examination was done to rule out any posterior segment disease. After collection of data, we analyzed and compared the intra ocular pressures between the two groups by using ANOVA in SPSS version 21.   Results: Average duration of using OCP was 14.9 months. There was no significant difference of Cup to Disc ratios between the two groups (p= 0.109). However, significant difference was noted between the IOP of OCP group and controls. (p=0.000). Conclusion: OCP significantly increase IOP even when used for short time period.

scholarly journals Neural Network Approach for Global Solar Irradiance Prediction at Extremely Short-Time-Intervals Using Particle Swarm Optimization Algorithm

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1213
Author(s):  
Ahmed Aljanad ◽  
Nadia M. L. Tan ◽  
Vassilios G. Agelidis ◽  
Hussain Shareef
Keyword(s):  
Neural Networks ◽  
Particle Swarm Optimization ◽  
Solar Irradiance ◽  
Particle Swarm ◽  
Time Interval ◽  
Time Intervals ◽  
Swarm Optimization ◽  
Backpropagation Neural Networks ◽  
Proposed Model ◽  
Short Time

Hourly global solar irradiance (GSR) data are required for sizing, planning, and modeling of solar photovoltaic farms. However, operating and controlling such farms exposed to varying environmental conditions, such as fast passing clouds, necessitates GSR data to be available for very short time intervals. Classical backpropagation neural networks do not perform satisfactorily when predicting parameters within short intervals. This paper proposes a hybrid backpropagation neural networks based on particle swarm optimization. The particle swarm algorithm is used as an optimization algorithm within the backpropagation neural networks to optimize the number of hidden layers and neurons used and its learning rate. The proposed model can be used as a reliable model in predicting changes in the solar irradiance during short time interval in tropical regions such as Malaysia and other regions. Actual global solar irradiance data of 5-s and 1-min intervals, recorded by weather stations, are applied to train and test the proposed algorithm. Moreover, to ensure the adaptability and robustness of the proposed technique, two different cases are evaluated using 1-day and 3-days profiles, for two different time intervals of 1-min and 5-s each. A set of statistical error indices have been introduced to evaluate the performance of the proposed algorithm. From the results obtained, the 3-days profile’s performance evaluation of the BPNN-PSO are 1.7078 of RMSE, 0.7537 of MAE, 0.0292 of MSE, and 31.4348 of MAPE (%), at 5-s time interval, where the obtained results of 1-min interval are 0.6566 of RMSE, 0.2754 of MAE, 0.0043 of MSE, and 1.4732 of MAPE (%). The results revealed that proposed model outperformed the standalone backpropagation neural networks method in predicting global solar irradiance values for extremely short-time intervals. In addition to that, the proposed model exhibited high level of predictability compared to other existing models.

scholarly journals One Year of the COVID-19 Pandemic in Galicia: A Global View of Age-Group Statistics during Three Waves

2021 ◽  
Vol 18 (10) ◽  
pp. 5104
Author(s):  
Iván Area ◽  
Henrique Lorenzo ◽  
Pedro J. Marcos ◽  
Juan J. Nieto
Keyword(s):  
Intensive Care Unit ◽  
Hospital Admissions ◽  
Age Groups ◽  
Age Group ◽  
Nw Spain ◽  
The Past ◽  
Global View ◽  
Time Period ◽  
Key Variables ◽  
One Year

In this work we look at the past in order to analyze four key variables after one year of the COVID-19 pandemic in Galicia (NW Spain): new infected, hospital admissions, intensive care unit admissions and deceased. The analysis is presented by age group, comparing at each stage the percentage of the corresponding group with its representation in the society. The time period analyzed covers 1 March 2020 to 1 April 2021, and includes the influence of the B.1.1.7 lineage of COVID-19 which in April 2021 was behind 90% of new cases in Galicia. It is numerically shown how the pandemic affects the age groups 80+, 70+ and 60+, and therefore we give information about how the vaccination process could be scheduled and hints at why the pandemic had different effects in different territories.

scholarly journals Political ideology and vaccination willingness: implications for policy design

2021 ◽  
Author(s):  
Marc Debus ◽  
Jale Tosun
Keyword(s):  
Side Effects ◽  
Political Ideology ◽  
Policy Design ◽  
Public Support ◽  
Individual Freedom ◽  
Short Time Period ◽  
Successful Development ◽  
Individual Level ◽  
Time Period ◽  
Short Time

AbstractThe COVID-19 pandemic has forced governments to impose major restrictions on individual freedom in order to stop the spread of the virus. With the successful development of a vaccine, these restrictions are likely to become obsolete—on the condition that people get vaccinated. However, parts of the population have reservations against vaccination. While this is not a recent phenomenon, it might prove a critical one in the context of current attempts to manage the COVID-19 pandemic. Consequently, the task of designing policies suitable for attaining high levels of vaccination deserves enhanced attention. In this study, we use data from the Eurobarometer survey fielded in March 2019. They show that 39% of Europeans consider vaccines to cause the diseases which they should protect against, that 50% believe vaccines have serious side effects, that 32% think that vaccines weaken the immune system, and that 10% do not believe vaccines are tested rigorously before authorization. We find that—even when controlling for important individual-level factors—ideological extremism on both ends of the spectrum explains skepticism of vaccination. We conclude that policymakers must either politicize the issue or form broad alliances among parties and societal groups in order to increase trust in and public support for the vaccines in general and for vaccines against COVID-19 in particular, since the latter were developed in a very short time period and resulted—in particular in case of the AstraZeneca vaccine—in reservations because of the effectiveness and side effects of the new vaccines.

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