scholarly journals Astrobiological Field Campaign to a Volcanosedimentary Mars Analogue Methane Producing Subsurface Protected Ecosystem: Imuruk Lake (Alaska)

2011 ◽  
Vol 2011 ◽  
pp. 1-8
Author(s):  
F. Gómez ◽  
O. Prieto-Ballesteros ◽  
D. Fernández-Remolar ◽  
J. A. Rodríguez-Manfredi ◽  
M. Fernández-Sampedro ◽  
...  
Keyword(s):  
Molecular Ecology ◽  
Point Of View ◽  
Land Bridge ◽  
High Hydrogen ◽  
Adverse Conditions ◽  
Life On Mars ◽  
Life Detection ◽  
National Preserve ◽  
Mars Exploration Rovers

Viking missions reported adverse conditions for life in Mars surface. High hydrogen signal obtained by Mars orbiters has increased the interest in subsurface prospection as putative protected Mars environment with life potential. Permafrost has attracted considerable interest from an astrobiological point of view due to the recently reported results from the Mars exploration rovers. Considerable studies have been developed on extreme ecosystems and permafrost in particular, to evaluate the possibility of life on Mars and to test specific automated life detection instruments for space missions. The biodiversity of permafrost located on the Bering Land Bridge National Preserve has been studied as an example of subsurface protected niche of astrobiological interest. Different conventional (enrichment and isolation) and molecular ecology techniques (cloning, fluorescence“in situ”probe hybridization, FISH) have been used for isolation and bacterial identification.

In situ TEM studies of irradiation effects for materials improvement

1991 ◽  
Vol 49 ◽  
pp. 452-453
Author(s):  
Charles W. Allen
Keyword(s):  
Nuclear Reactor ◽  
Austenitic Stainless Steels ◽  
High Energy ◽  
Point Of View ◽  
In Situ Tem ◽  
Irradiation Effects ◽  
Tem Analysis ◽  
Radiation Induced ◽  
Analytical Tools

Irradiation effects studies employing TEMs as analytical tools have been conducted for almost as many years as materials people have done TEM, motivated largely by materials needs for nuclear reactor development. Such studies have focussed on the behavior both of nuclear fuels and of materials for other reactor components which are subjected to radiation-induced degradation. Especially in the 1950s and 60s, post-irradiation TEM analysis may have been coupled to in situ (in reactor or in pile) experiments (e.g., irradiation-induced creep experiments of austenitic stainless steels). Although necessary from a technological point of view, such experiments are difficult to instrument (measure strain dynamically, e.g.) and control (temperature, e.g.) and require months or even years to perform in a nuclear reactor or in a spallation neutron source. Consequently, methods were sought for simulation of neutroninduced radiation damage of materials, the simulations employing other forms of radiation; in the case of metals and alloys, high energy electrons and high energy ions.

Hydrogen-induced amorphization and embrittlement resistance in Ti-based in situ composite with bcc-phase in an amorphous matrix

2007 ◽  
Vol 22 (2) ◽  
pp. 428-436 ◽  
Author(s):  
S. Jayalakshmi ◽  
J.P. Ahn ◽  
K.B. Kim ◽  
E. Fleury
Keyword(s):  
Hydrogen Embrittlement ◽  
Amorphous Alloys ◽  
Amorphous Matrix ◽  
Mechanical Tests ◽  
High Concentration ◽  
High Hydrogen ◽  
In Situ Composite ◽  
Bcc Phase ◽  
Embrittlement Resistance

We report the hydrogenation characteristics and mechanical properties of Ti50Zr25Cu25 in situ composite ribbons, composed of β-Ti crystalline phase dispersed in an amorphous matrix. Upon cathodic charging at room temperature, high hydrogen absorption up to ∼60 at.% (H/M = ∼1.2) is obtained. At such a high concentration, hydrogen-induced amorphization occurs. Mechanical tests conducted on the composite with varying hydrogen concentrations indicate that the Ti50Zr25Cu25 alloy is significantly resistant to hydrogen embrittlement when compared to conventional amorphous alloys. A possible mechanism that would contribute toward hydrogen-induced amorphization and hydrogen embrittlement is discussed.

Ship Drag Reduction by Microalgal Biopolymers: A Feasibility Analysis

2007 ◽  
Vol 51 (04) ◽  
pp. 326-337
Author(s):  
K. Gasljevic ◽  
E. F. Matthys
Keyword(s):  
Drag Reduction ◽  
Consumption Rate ◽  
Synthetic Polymers ◽  
Point Of View ◽  
Technical Issues ◽  
Fuel Costs ◽  
Propulsion Power ◽  
Ship Speed ◽  
In Situ Production

We have investigated the feasibility of using high-molecular-weight polysaccharides produced by marine microalgae to reduce the drag on ships and therefore to be able to reduce the needed propulsion power and fuel costs or, alternatively, to increase the ship speed. Experimental and analytical studies were used to answer four critical questions:How suitable are the biopolymers for drag reduction on ships?What is the needed polymer consumption rate at a given level of drag reduction?What is the achievable polymer production rate that can be achieved by the microalgae?What are possible modes of implementation of the proposed technology? It is seen that in situ production of biopolymers by microalgae growing on the hull may be a possible approach to polymeric ship drag reduction. Production of biopolysaccharide off the ship and even harvesting it from the ocean are other possibilities. The use of biopolymers is naturally advantageous from an environmental point of view as well. Some comparison of biopolymers and synthetic polymers is also presented. Several technical issues remain to be investigated, but the information available suggests that biopolymers may be the best additives for drag reduction on ships.

Emissions and Noise Pollution Diagnosis of a Turbogas Power Plant During Commissioning Service

2010 ◽  
Author(s):  
Norberto Pe´rez Rodri´guez ◽  
Erik Rosado Tamariz ◽  
Rafael Garci´a Illescas
Keyword(s):  
Power Plant ◽  
Cooling System ◽  
Near Field ◽  
Noise Pollution ◽  
Point Of View ◽  
International Standards ◽  
Partial Load ◽  
The City ◽  
Permissible Deviation

This work is focused on the diagnosis of behavior, from the point of view of control emissions and noise level, of a power Turbogas plant during the process of commissioning, to guarantee that its operation complies with national and international standards. The environmental diagnosis of the power plant was developed as part of the performance evaluation of the unit. The conditions of the unit evaluation include operation at base load and partial load, as well as time periods for load changes. The evaluated power plant consists of an aeroderivative gas turbine installed in a simple cycle, operating with a cooling system (chiller) installed in the urban zone of Mexico City. Therefore, it should comply with the legislation and regulations of the city concerning air pollution and allowed noise, besides the international standards established by the manufacturer. The study includes emissions measurements using a Continuous Emissions Monitoring System installed in-situ, previously calibrated and checked during and after the test which was found inside the permissible deviation of 3%. Measurements were recorded at intervals of 5 minutes during test periods of 110 minutes for each load and 45 minutes for load changes. On the other hand, noise pressure evaluation was carried out in near field as well as far field produced by the power plant during operation. Measurements were carried out by using precision instruments installed specifically for it. A temporary system for obtaining data was used to monitoring the environmental conditions every 30 seconds. It was possible to verify that the turbogenerator complies with all noise levels and contaminant emissions requirements and regulations according to the limits established by the manufacturer and national and international standards.

Positron Lifetime Calculation for Plastic Deformed Nanocrystalline Copper

2017 ◽  
Vol 373 ◽  
pp. 31-34
Author(s):  
Kai Zhou ◽  
Ting Zhang
Keyword(s):  
Positron Annihilation ◽  
Deformation Mechanism ◽  
Positron Lifetime ◽  
Experimental Information ◽  
Point Of View ◽  
Nanocrystalline Copper ◽  
Mean Grain Size ◽  
Positron Lifetimes ◽  
Boundary Deformation

Positron lifetime calculation has been performed on a computer-generated nanocrystalline copper with a mean grain size of 9.1 nm during its deformation. For the undeformed and deformed nanocrystalline copper, calculated positron lifetimes are around 157 ps which come from the positron annihilation in the free volume in grain boundaries. Due to the grain-boundary deformation mechanism, no vacancies or vacancy clusters will be induced in grains during the plastic deformation of the nanocrystalline copper, which is different to the deformation of the conventional polycrystal. From this point of view, in-situ positron annihilation measurements can provide important experimental information on the deformation mechanism of nanocrystalline metals.

In Situ HREm of Reactions at Interfaces

1997 ◽  
Vol 3 (S2) ◽  
pp. 621-622 ◽  
Author(s):  
R. Sinclair ◽  
T. Itoh ◽  
H. J. Lee ◽  
K. W. Kwon
Keyword(s):  
Chemical Interaction ◽  
High Resolution Electron Microscopy ◽  
Point Of View ◽  
Interface Chemistry ◽  
Amorphous Phases ◽  
Resolution Electron ◽  
Analogous Manner ◽  
The Stability ◽  
Basic Studies

Reactions at solid-solid interfaces are important both scientifically and technologically. Firstly, there is quite a wide variety of possibilities. Materials can react with one another, forming equilibrium, meta-stable or even amorphous phases. The interface can provide a means to promote phase reactions kinetically, in an analogous manner to catalysis. Even when the materials are mutually compatible chemically, the interface topography and atomic structure can evolve over the course of time. From the practical point-of-view, changes in the interface chemistry and structure can profoundly alter the physical properties. This is especially notable in thin film technology, whereby the interfaces constitute a signigicant proportion of the whole device. In this article, contributions to understanding this field are illustrated through application of in situ and high-resolution electron microscopy (HREM).Basic studies of metal-semicoductor interfacial reactions have been successfully carried out for a number of years. of increasing importance in microelectronics is the stability of layers which prevent chemical interaction, namely the diffusion barriers.

scholarly journals The Situation of Cervical Cancers in the Context of Female Genital Cancer Clustering and Burden of Disease in Arad County, Romania

2019 ◽  
Vol 8 (1) ◽  
pp. 96 ◽  
Author(s):  
Ana-Liana Tataru ◽  
Gheorghe Furau ◽  
Jompan Afilon ◽  
Cringu Ionescu ◽  
Mihai Dimitriu ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Squamous Cell ◽  
Histopathological Examination ◽  
Squamous Cell Carcinomas ◽  
Point Of View ◽  
Clinical Staging ◽  
Cervical Cancers ◽  
Genital Cancer ◽  
Disability Adjusted Life

Romania has the highest incidence of cervical cancer morbidity and mortality in Europe. This study identifies the major clusters for genital cancers, observes the features of genital and cervical cancer, and determines the extent to which cancer is a contributor to total Disability-Adjusted Life Year (DALY). Spatial analysis used Besag and Newell’s method for genital cancer distribution, prevalence considered Arad County patients records (2008–2017), and DALY was determined according to WHO methodology and GLOBOCAN 2013 data. Diagnosis was established by histopathological examination of diagnostic biopsies or tissues obtained by surgical procedures, followed by clinical staging. 1695 women were recorded with genital cancer. Of these, 14.9% of lesions were in situ (n = 252) and 74.20% of cases were recorded in stage III or IV (n = 1258) (p < 0.0001). Over 90% of cervical cancers were squamous cell carcinomas (n = 728), 33.76% of endometrial cancers were adenocarcinomas in situ (n = 131), 32.42% of ovarian cancers were serous adenocarcinomas (n = 131), and 70.58% of vulvar cancers were squamous cell carcinomas (n = 48) (p < 0.0001). DALY/1000 was 67.2 for genital cancers and 33 for cervical cancers. From the point of view of Romanian women, cervical cancer remains one of the major problems that need to be dealt with and access to optimal treatment proves to be extremely limited.

Bluespace, Senses, Wellbeing, and Surfing: Prototype Cyborg Theory-Methods

2020 ◽  
pp. 019372352092859 ◽  
Author(s):  
lisahunter ◽  
Lyndsey Stoodley
Keyword(s):  
Water Relations ◽  
Point Of View ◽  
Theory Method ◽  
Multiple Perspectives ◽  
Visual Evidence ◽  
Auto Ethnography ◽  
Cyborg Theory

Bluespace, where water people immerse themselves for thrills, therapy, or thalassography, is constantly fluctuating, influenced by materials, nature, and discourse. Drawing on onto-epistemological aspects of embodied theory-method, we report entangled prototype “cyborg” in situ strategies (mobile, sensory [auto]ethnography, and self-interview) to notice, record, and ultimately create human–water relations, from the perspective of a surfer. Audio/-visual evidence, from multiple perspectives, folding time, and several point-of-view devices, enabled unique insights into voiced thoughts, sights, sounds, and conscious/subconscious practices that occur in surfing. Such insights into the relationships, experiences, and movements of surfers inform research, such as to wellbeing and to the challenges of investigating bluespace. We offer cyborg theory-method for further methodological and onto-epistemological consideration in such relationships, contributing to a growing understanding of more-than-human engagement with watery worlds.

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