scholarly journals Atmospheric Pressure Anomalies over Earthquakes Epicenters

2021 ◽  
Vol 2 (4) ◽  
pp. 21-25
Author(s):  
Eladio Zárate Hernández ◽  
Mario Fernández Arce
Keyword(s):  
Costa Rica ◽  
Atmospheric Pressure ◽  
Stress Pattern ◽  
Pressure Pattern ◽  
A Value ◽  
Pressure Anomaly

This article is an analysis of the anomalies in atmospheric pressure days before and during the occurrence of earthquakes. The research started from the review of scientific articles in which it has been proposed that atmospheric events generate or trigger seismicity, and that earthquakes alter the atmosphere. Therefore, the atmospheric pressure pattern in Costa Rica during earthquakes with a magnitude greater than or equal to 6.5 Mw, for the period 1950 – 2020, was studied in order to investigate a possible link between atmospheric events and underground processes of the planet. For this, atmospheric pressure anomaly maps were drawn in which the epicenter of the earthquakes was located. Among the results, it stands out that 64% of the epicenters occurred in areas where the pressure anomaly had a value close to or equal to zero. This could indicate, as other authors have suggested, that atmospheric pressure alters the cortical stress pattern, thus contributing to the triggering of earthquakes.

scholarly journals The thermal decomposition of nitrous oxide at pressures up to forty atmospheres

1934 ◽  
Vol 144 (852) ◽  
pp. 386-412 ◽  
Keyword(s):  
Activation Energy ◽  
Nitrous Oxide ◽  
Atmospheric Pressure ◽  
Initial Pressure ◽  
Bimolecular Reaction ◽  
Absolute Temperature ◽  
Velocity Constant ◽  
A Value ◽  
Straight Line ◽  
Rate Of Reaction

Nitrous oxide decomposes to nitrogen and oxygen at velocities which can be conveniently measured at temperatures between 600° and 850° C. M. A. Hunter investigated the reaction by streaming the gas through a porcelain bulb in a furnace and measuring the decomposition for different times of passage. No attempt was made to determine whether the reaction is homogeneous or heterogeneous. The effect of wide variation of pressure was not used to determine its order, since the reaction was followed only over small ranges of decomposition at atmospheric pressure. From the velocity of decomposition, however, bimolecular constants were obtained which could be represented by the equation: ln k = 24·12 - 31800/T, where k is the bimolecular velocity constant and T the absolute temperature. If this equation holds, the activation energy of the bimolecular reaction is 62,040 cal./gm. mol. A much more thorough examination of the reaction was made by Hinshelwood and Burk, who measured the rate of reaction by following the pressure increase at constant volume in a silica bulb. The reaction was proved to be homogeneous. The initial pressure was varied between 50 and 500 mm. Hg, and it was found that the reciprocal of the half-lives when plotted against the initial pressures gave a straight line. true bimolecular reaction requires the straight line 1/ t ½ = ka , where t ½ is the half-line, and k the velocity constant, and a the initial concentration. The line through the experimental points showed a small intercept on the 1/ t ½ axis for which no explanation was offered at the time. From the variation of the bimolecular constants between 565° and 852° C. the activation energy of the reaction was calculated to be 58,450 cal./gm. mol. If the reaction were a bimolecular one dependent on immediate decomposition at each activating collision of the molecules the number of molecules reacting per second should be equal to Z x e -E/RT , where Z is the number of molecules colliding per second and E is the activation energy. From the observed rate of reaction at 1000° K. a value of 55,000 cal./gm. mol. was found for the activation energy. The fairly close agreement between the two values of the activation energy, 58,450 and 55,000 cal./gm. mol. and the manner in which the half-life varied with pressure provided good grounds for believing the reaction to be a simple bimolecular one, dependent only on collisions between the molecules.

Mass transfer and kinetics of the chemical vapor deposition of SiC onto fibers

1998 ◽  
Vol 13 (8) ◽  
pp. 2251-2261 ◽  
Author(s):  
W. Jack Lackey ◽  
Sundar Vaidyaraman ◽  
Bruce N. Beckloff ◽  
Thomas S. Moss III ◽  
John S. Lewis
Keyword(s):  
Mass Transfer ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Atmospheric Pressure ◽  
Chemical Vapor ◽  
Total Flow ◽  
A Value ◽  
Factor Expression ◽  
Kinetics Of ◽  
Best Fit

An internally consistent set of data was generated for the chemical vapor deposition (CVD) of SiC from methyltrichlorosilane (MTS) and H2 at atmospheric pressure. A moving fiber tow was used as the substrate. Coating rates between 0.3 and 3.7 µm/min and deposition efficiencies between 24 and 48% were obtained for MTS and H2 flow rates in the range 30 to 200 cm3/min and 300 to 2000 cm3/min, respectively. The data were analyzed and found to be best fit under a mass transfer regime. Based on this fit, a value of the constant in the Chilton–Colburn j factor expression for a moving fiber tow was estimated to be 2.74 × 10−6 with a standard deviation of 3.2 × 10−7. The efficiency of the reaction was found to decrease with increases in the total flow rate, indicating that the effect of the decreased residence time of reagents in the reactor was larger than the increase in the mass transfer coefficient. Finally, a comparison between the efficiencies for a stationary and a moving tow revealed that the moving tow had a higher efficiency, possibly due to a disruption of the boundary layer by the tow motion or due to the decrease in the canning of the moving tow.

scholarly journals Correlation of Clinical and Histopathological Diagnosis of Oral Mucosa Lesions at the University of Costa Rica Between 2008 and 2015

2020 ◽  
pp. 407-415
Author(s):  
Yadira V. Boza Oreamuno ◽  
Andrea López Soto
Keyword(s):  
Costa Rica ◽  
Oral Mucosa ◽  
Premalignant Lesions ◽  
Histopathological Diagnosis ◽  
Substantial Agreement ◽  
Kappa Test ◽  
A Value ◽  
Autoimmune Conditions ◽  
Diagnostic Hypothesis ◽  
The University

The objective of this study is to determine the existing concordance between the clinical and histopathological diagnosis of lesions in the oral mucosa at the Faculty of Dentistry of the University of Costa Rica (UCR). A retrospective study of 261 reports of oral lesions recovered from the biopsy archive of the UCR Faculty of Dentistry from 2008 to 2015. Of the total reports 165 were included in the analysis, 96 (36.8%) did not have any diagnostic hypotheses. The concordance between the clinical and histopathological diagnosis was verified by the Kappa test. Concordance with the first diagnostic hypothesis was presented in 114 (69.1%) cases, the value of kappa was 0.663 (substantial agreement) and 36.8% without clinical diagnosis only a description of the lesion.  The premalignant lesions presented an excellent concordance (kappa=0.902). The concordance of the group of non-neoplastic proliferative lesions was moderate (kappa=0.504) and the dermatological and autoimmune conditions with negligible concordance (0.157). Concordance occurred in the majority of the patients investigated with a value corresponding to a substantial agreement, however, the percentage of reports that did not have a clinical hypothesis should be improved.

III—The Meteorological Limitations on Pressure Pattern Flying

1948 ◽  
Vol 1 (01) ◽  
pp. 55-61
Author(s):  
J. S. Sawyer
Keyword(s):  
Pressure Distribution ◽  
Atmospheric Pressure ◽  
Geostrophic Wind ◽  
Pressure Pattern ◽  
Low Latitudes ◽  
Atmospheric Pressure Distribution

The preceding papers indicate that the theory of pressure pattern flying assumes that the wind satisfies the conditions imposed by the geostrophic wind equation and that the atmospheric pressure distribution is not changing. These conditions are not satisfied in the atmosphere, and the errors caused by their non-fulfilment are discussed in the following paragraphs.Effect of departures of wind from geostrophic. The geostrophic wind equation is derived on the assumption that the wind blows uniformly without acceleration and without friction. These conditions are never satisfied in the atmosphere, nevertheless the practising meteorologist has found that the geostrophic wind represents a useful approximation to the true wind. There are certain exceptions of which the most important are in low latitudes and at levels below 2000 feet.

Glycolytic Aminolysis of Poly (Ethylene Terephthalate) Waste at Atmospheric Pressure for Recovery of a Value Added Insecticide

2005 ◽  
Vol 44 (1) ◽  
pp. 163-181 ◽  
Author(s):  
A.S. Goje* ◽  
S.A. Thakur ◽  
Y.P. Chauhan ◽  
Tushar M. Patil ◽  
S.A. Patil ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Ethylene Terephthalate ◽  
Value Added ◽  
A Value ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene

scholarly journals Hazards Analysis in the Canton La Unión, Cartago, Costa Rica

2021 ◽  
Vol 2 (2) ◽  
pp. 30-34
Author(s):  
Jorge Rodríguez Campos ◽  
Mario Fernandez Arce
Keyword(s):  
Risk Management ◽  
Spatial Distribution ◽  
Costa Rica ◽  
Local Government ◽  
Disaster Risk ◽  
Spatial Extent ◽  
Field Surveys ◽  
A Value ◽  
Density Index ◽  
The Impact

The hazards from the canton La Unión were identified, analyzed, and described. A value ranging from 0 to 1 was assigned to each threat in the Minimum Geostatistical Units (MGU), to estimate the dangers density in the study area. This article shows the spatial distribution of such index. The manifestation of several natural and anthropic events forces to investigate and understand such processes, in order to improve Disaster Risk Management (DRM) in the Canton and provide inputs to the Local Government to carry out such work. The investigation required a bibliographic review to know the impact of past incidents, field surveys to determine the spatial extent of the threats, and the calculation of a hazard’s density index. According to the results, earthquakes are the main danger in La Union and the Center, South and West of the canton are the areas with the highest hazards density.

scholarly journals The perception of lexical stress in words within a sentence

Loquens ◽  
2017 ◽  
Vol 3 (2) ◽  
pp. 033 ◽  
Author(s):  
Joaquim Llisterri ◽  
María J. Machuca ◽  
Antonio Ríos ◽  
Sandra Schwab
Keyword(s):  
Costa Rica ◽  
Fundamental Frequency ◽  
Stress Pattern ◽  
Lexical Stress ◽  
Acoustic Parameters ◽  
Word Level ◽  
The Relationship

The acoustic and perceptual correlates of stress in Spanish have been usually studied at the word level, but few investigations have considered them in a wider context. The aim of the present work is to assess the role of fundamental frequency, duration and amplitude in the perception of lexical stress in Spanish when the word is part of a sentence. An experiment has been carried out in which the participants (39 listeners, 20 from Costa Rica and 19 from Spain) had to identify the position of the lexical stress in words presented in isolation and in the same words embedded in sentences. The stimuli in which the position of the stress was not correctly identified have been acoustically analysed to determine the cause of identification errors. Results suggest that the perception of lexical stress in words within a sentence depends on the stress pattern and on the relationship between the values of the acoustic parameters responsible for the prominence of the stressed vowel and those corresponding to the adjacent unstressed vowels.

scholarly journals Assessment of construction waste management practice: a case study in Costa Rica

2007 ◽  
pp. 85-95
Author(s):  
Lilliana Abarca ◽  
Ir. F.M. Scheublin ◽  
Hijmen Van Twillert
Keyword(s):  
Costa Rica ◽  
Management Practice ◽  
Developed Countries ◽  
Construction And Demolition Waste ◽  
Demolition Waste ◽  
Construction Waste ◽  
A Value ◽  
Soil Piping ◽  
Concrete Blocks

The construction industry deals with the provision of shelter and infrastructure for acontinuing growing population and urbanization, especially in developing countries, Thissector is well known as a huge consumer of natural resources; which produces a significantquantity of construction and demolition waste, Data about the situation of construction wastegeneration in Costa Rica is scarce and the objectives of the study were to develop a baselinestudy to determine quantities and composition of the waste, as well as, motivators and barriersfor achieving a more sustainable activity, This paper draws the findings of the surveyundertaken by means of questionnaires, interviews and site visits, The composition basicallyis wood, soil, piping materials, corrugated roof sheets, wires, packaging materials (paper,plastic and cardboard), cement, concrete, blocks, paints and debris, The amounts (either byvolume or by weight) of these streams are unknown since the majority of the companies don'tkeep track of these data, It is suggested a value of I 00 kg/m2 as an educated guess of theamount of construction waste produced, This high amount, compared to lower values found inliterature for developed countries, could be explained by the general lack of awareness andinformation on environmental issues as well as lack of technologies, governmentalenforcement and market incentives to improve the environmental footprint of the sector,

Effects of Volatilization on Groundwater Chemistry

2002 ◽  
Vol 757 ◽  
Author(s):  
A. L. Pulvirenti ◽  
K. M. Needham ◽  
M. A. Adel-Hadadi ◽  
E. J. Bishop ◽  
A. Barkatt ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Ambient Air ◽  
Pressure Vessels ◽  
General Corrosion ◽  
Solute Content ◽  
Corrosion Rates ◽  
A Value ◽  
Alloy 22 ◽  
Late Stages

ABSTRACTBoth concentrated and dilute simulated solutions of saturated J13 and unsaturated UZ pore water were concentrated through distillation of the solutions under atmospheric pressure. It was observed that condensed vapors from the pH of J13 waters steadily rose during the distillations to a value of 10, while the pH of UZ waters remained steady until 90% of the volume of the solution had been distilled, after which the pH of the condensed vapors dropped precipitously, often below 1. Residual solutions analyzed when most of the solution had been distilled away were also found to be extremely acidic. The temperature of these residual solutions was around 144°C due to their high solute content causing boiling point elevation. All experiments were performed with the condenser open to ambient air at atmospheric pressure. The pH drop during the distillation of UZ water is attributed largely to the presence of large amounts of magnesium. Specimens of Alloy 22 tested in the residual solutions of at their boiling temperature (around 144°C) showed significant rates of general corrosion over a broad range, often approaching 1 mm/year. Similarly high corrosion rates were also observed in tests on Alloy 22 specimens in condensates obtained during the late stages of the distillation. These tests were performed either in situ at 75–80°C using a Soxhlet extractor, or in separate pressure vessels at temperatures between 90 and 130°C.

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