The segmental impression technique: A straightforward solution to a difficult problem

2020 ◽  
Vol 124 (1) ◽  
pp. 10-13
Author(s):  
Islam Abd Alraheam ◽  
Terry Donovan
Keyword(s):  
Difficult Problem ◽  
Impression Technique ◽  
Straightforward Solution

CO2 Activation on Heterostructures of Bi2O3-Nanocluster Modified TiO2: Promoting the Critical First Step in CO2 Conversion

2018 ◽  
Author(s):  
Michael Nolan
Keyword(s):  
Metal Oxide ◽  
Density Functional ◽  
Initial Step ◽  
Difficult Problem ◽  
Carbonate Formation ◽  
Structural Distortions ◽  
Strong Adsorption ◽  
Two Factors ◽  
Key Steps ◽  
Recent Experimental Work

The conversion of CO<sub>2</sub> to fuels is of significant importance in enabling the production of sustainable fuels, contributing to alleviating greenhouse gas emissions. While there are a number of key steps required to convert CO<sub>2</sub>, the initial step of adsorption and activation by the catalyst is critical. Well-known metal oxides such as oxidised TiO<sub>2</sub> or CeO<sub>2</sub> are unable to promote this step. In addressing this difficult problem, recent experimental work shows the potential for bismuth-containing materials to activate and convert CO<sub>2</sub>, but the origin of this activity is not yet clear. Additionally, nanostructures can show enhanced activity towards CO<sub>2</sub>. In this paper we present density functional theory (DFT) simulations of CO<sub>2</sub> activation on heterostructured materials composed of extended rutile and anatase TiO<sub>2</sub> surfaces modified with nanoclusters with Bi<sub>2</sub>O<sub>3</sub> stoichiometry. These heterostructures show low coordinated Bi sites in the nanoclusters and a valence band edge that is dominated by Bi-O states. These two factors mean that supported Bi<sub>2</sub>O<sub>3</sub> nanoclusters are able to adsorb and activate CO<sub>2</sub>. Computed adsorption energies lie in the range of -0.54 eV to -1.01 eV. In these strong adsorption modes, CO<sub>2</sub> is activated, in which the molecule bends giving O-C-O angles of 126 - 130<sup>o</sup> and elongation of C-O distances up to 1.28 Å, with no carbonate formation. The electronic properties show a strong CO<sub>2</sub>-Bi-oxygen interaction that drives the interaction of CO<sub>2</sub> to induce the structural distortions. Bi<sub>2</sub>O<sub>3</sub>-TiO<sub>2</sub> heterostructures can be reduced to form Bi<sup>2+</sup> and Ti<sup>3+</sup> species. The interaction of CO<sub>2</sub> with this electron-rich, reduced system can produce CO directly, reoxidising the heterostructure or form an activated carboxyl species (CO<sub>2</sub><sup>-</sup>) through electron transfer from the heterostructure to CO<sub>2</sub>. These results highlight that a semiconducting metal oxide modified with suitable metal oxide nanoclusters can activate CO<sub>2</sub>, thus overcoming the difficulties associated with the difficult first step in CO<sub>2</sub> conversion.

Biochemical Markers in Patients with Readmission for Congestive Heart Failure

2018 ◽  
Vol 69 (7) ◽  
pp. 1687-1691
Author(s):  
Razan Al Namat ◽  
Mihai Constantin ◽  
Ionela Larisa Miftode ◽  
Andrei Manta ◽  
Antoniu Petris ◽  
...  
Keyword(s):  
Heart Failure ◽  
Congestive Heart Failure ◽  
Rural Areas ◽  
Discharge Planning ◽  
Difficult Problem ◽  
Uncontrolled Hypertension ◽  
Medical Attention ◽  
Family Doctors ◽  
Increased Risk ◽  
Risk Patients

Repetitive or recurrent hospitalizations are a general major health issue in patients with chronic disease. Congestive heart failure, is associated with a high incidence and presence of early rehospitalization, but variables in order to identify patients at increased risk and also an analysis of potentially remediable factors contributing to readmission have not been previously reported and it remains still a difficult problem. We retrospectively assessed 100 patients aged between 48-85 years old, of which 75% were men, who had been hospitalized with documentation of congestive heart failure in St. Spiridon County Emergency Hospital. They were hospitalized between 2010-2017. Even if recurrent heart failure was the most common cause for readmission or rehospitalization, other cardiac disorders and noncardiac illnesses were also accounted for readmission. Predictive factors of an increased probability of readmission included prior patient�s medical heart failure history, heart failure decompensation precipitated or accelerated by an ischaemic episode, atrial fibrillation or uncontrolled hypertension. Factors contributing to preventable readmissions included noncompliance with medications or diet, inadequate discharge planning or follow-up, failure of both social support system and the seek of a promp medical attention when symptoms reappeared. We also identified an inappropriate colaboration with family doctors especially for the patients from rural areas. Patients were more likely to cite side effects of prescribed medications rather than nonadherence as a precipitating factor for readmission. Thus, we can appreciate that early rehospitalization in patients with congestive heart failure may be avoidable in up to 50% of cases. Identification of high risk patients is possible and also necessary shortly after admission in order to identify nonpharmacological interventions designed to decrease readmission frequency.

COMPLEX PROSTHETIC REHABILITATION OF THE PATIENT WITH MALIGNANT TUMOR OF OROPHARYNGEAL REGION DURING ANTITUMOR TREATMENT: CASE REPORT

2019 ◽  
Vol 65 (2) ◽  
pp. 287-293
Author(s):  
Yekaterina Izhnina ◽  
Yekaterina Kochurova ◽  
Natalya Lapina ◽  
Karina Seferyan
Keyword(s):  
Case Report ◽  
Malignant Tumor ◽  
Methodological Approach ◽  
Difficult Problem ◽  
Prosthetic Rehabilitation ◽  
Anatomic Structure

Treatment of patients with malignant tumor of oropharyngeal region is a difficult problem due to the last detection of diseases and complex anatomic structure, despite the emergence new and improvement methods of the treatment of cancer of oropharyngeal region. Complex rehabilitation of this patients presents great difficulties due to the disturbance of breath, swallowing, speech, and the lack of a single methodological approach to treatment. It is needs to improve the effectiveness of prosthetic care for patients with malignant tumor of oropharyngeal region.

Urban stormwater: the analysis of the failure of the alternative techniques and the management of quality

1995 ◽  
Vol 32 (1) ◽  
pp. 33-39
Author(s):  
E. Alfakih ◽  
S. Barraud ◽  
Y. Azzout ◽  
B. Chocat
Keyword(s):  
Stormwater Management ◽  
Difficult Problem ◽  
Management Approach ◽  
Alternative Technique ◽  
Urban Stormwater ◽  
Urban Stormwater Management ◽  
Porous Pavement ◽  
Alternative Techniques ◽  
Design Construction

The implementation of alternative techniques in urban stormwater management is a difficult problem in terms of choice, design, construction, and operating. We applied a quality management approach to try and have a better understanding of these techniques. The quality of an alternative technique in urban stormwater management is defined; the factors that lead to failures were identified and analysed. In order to reduce these factors, tools were developed, and measures that allow the achievement of the necessary standard of quality are suggested. In this article, all the illustrations refer to the porous pavement technique.

Tribology of rail bogie

2018 ◽  
Vol 77 (4) ◽  
pp. 230-240
Author(s):  
D. P. Markov
Keyword(s):  
Contact Fatigue ◽  
Basic Element ◽  
Difficult Problem ◽  
Railway Track ◽  
Rolling Stock ◽  
Kinematic Parameters ◽  
Approximate Estimation ◽  
Railway Bogie ◽  
Classical Calculation

Railway bogie is the basic element that determines the force, kinematic, power and other parameters of the rolling stock, and its movement in the railway track has not been studied enough. Classical calculation of the kinematic and dynamic parameters of the bogie's motion with the determination of the position of its center of rotation, the instantaneous axes of rotation of wheelsets, the magnitudes and directions of all forces present a difficult problem even in quasi-static theory. The paper shows a simplified method that allows one to explain, within the limits of one article, the main kinematic and force parameters of the bogie movement (installation angles, clearance between the wheel flanges and side surfaces of the rails), wear and contact damage to the wheels and rails. Tribology of the railway bogie is an important part of transport tribology, the foundation of the theory of wheel-rail tribosystem, without which it is impossible to understand the mechanisms of catastrophic wear, derailments, contact fatigue, cohesion of wheels and rails. In the article basic questions are considered, without which it is impossible to analyze the movement of the bogie: physical foundations of wheel movement along the rail, types of relative motion of contacting bodies, tribological characteristics linking the force and kinematic parameters of the bogie. Kinematics and dynamics of a two-wheeled bogie-rail bicycle are analyzed instead of a single wheel and a wheelset, which makes it clearer and easier to explain how and what forces act on the bogie and how they affect on its position in the rail track. To calculate the motion parameters of a four-wheeled bogie, it is represented as two two-wheeled, moving each on its own rail. Connections between them are replaced by moments with respect to the point of contact between the flange of the guide wheel and the rail. This approach made it possible to give an approximate estimation of the main kinematic and force parameters of the motion of an ideal bogie (without axes skewing) in curves, to understand how the corners of the bogie installation and the gaps between the flanges of the wheels and rails vary when moving with different speeds, how wear and contact injuries arise and to give recommendations for their assessment and elimination.

Aproveitamento de Recursos Hídricos em Micro Bacias Hidrográficas Utilizando Sistemas de Informação Geográfica

1997 ◽  
Vol 24 (1-2) ◽  
pp. 3
Author(s):  
LUIZ ERNESTO RENUNCIO ◽  
CARLOS LOCH
Keyword(s):  
Water Supply ◽  
Water Consumption ◽  
Industrial Development ◽  
Difficult Problem ◽  
Planning Unit ◽  
Large Databases ◽  
Spatially Distributed ◽  
Water Supply Reservoir ◽  
Consumption Demand ◽  
Previous Location

The daily increase of inhabitants in our cities, when associated with the commercial and industrial development, leads to larger water consumption demand. Despite the larger demand the resource may maintain its quality. The solutions to these difficult problem frequently require the capacity to store manage and analyze large databases, spatially distributed. This work presents the methodology adopted to plan and locate the best site for a water supply reservoir, with the aggregation of a GIS structured database, regarding a microbasin as the planning unit. This was held in the municipality of Cocal do Sul, Brazil. The result was a previous location for the water supply reservoir, considering also other uses for the water that should be stored.

North and South

2008 ◽  
Author(s):  
Elizabeth Gaskell ◽  
Sally Shuttleworth
Keyword(s):  
Middle Class ◽  
Difficult Problem ◽  
The Novel ◽  
Social Authority ◽  
Industrial Town ◽  
Middle Class Woman ◽  
Class Woman ◽  
And Gender ◽  
North And South ◽  
Obedience To Authority

`She tried to settle that most difficult problem for women, how much was to be utterly merged in obedience to authority, and how much might be set apart for freedom in working.’ North and South is a novel about rebellion. Moving from the industrial riots of discontented millworkers through to the unsought passions of a middle-class woman, and from religious crises of conscience to the ethics of naval mutiny, it poses fundamental questions about the nature of social authority and obedience. Through the story of Margaret Hale, the middle-class southerner who moves to the northern industrial town of Milton, Gaskell skilfully explores issues of class and gender in the conflict between Margaret’s ready sympathy with the workers and her growing attraction to the charismatic mill ownder, John Thornton. This new revised and expanded edition sets the novel in the context of Victorian social and medical debate.

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