scholarly journals Modeling and experimental studies of oxide covered metal surfaces: TiO sub 2 /Ti a model system

1991 ◽  
Author(s):  
W.H. Smyrl
Keyword(s):  
Metal Surfaces ◽  
Experimental Studies ◽  
Model System

scholarly journals Bacteriophage Migration via Nematode Vectors: Host-Parasite-Consumer Interactions in Laboratory Microcosms

2006 ◽  
Vol 72 (3) ◽  
pp. 1974-1979 ◽  
Author(s):  
John J. Dennehy ◽  
Nicholas A. Friedenberg ◽  
Yul W. Yang ◽  
Paul E. Turner
Keyword(s):  
Experimental Studies ◽  
Virus Transmission ◽  
Growth Dynamics ◽  
Model System ◽  
Pathogen Transmission ◽  
Trophic Levels ◽  
Future Research ◽  
Evolution Of Virulence ◽  
Consumer Interactions ◽  
Host Parasite

ABSTRACT Pathogens vectored by nematodes pose serious agricultural, economic, and health threats; however, little is known of the ecological and evolutionary aspects of pathogen transmission by nematodes. Here we describe a novel model system with two trophic levels, bacteriophages and nematodes, each of which competes for bacteria. We demonstrate for the first time that nematodes are capable of transmitting phages between spatially distinct patches of bacteria. This model system has considerable advantages, including the ease of maintenance and manipulation at the laboratory bench, the ability to observe many generations in short periods, and the capacity to freeze evolved strains for later comparison to their ancestors. More generally, experimental studies of complex multispecies interactions, host-pathogen coevolution, disease dynamics, and the evolution of virulence may benefit from this model system because current models (e.g., chickens, mosquitoes, and malaria parasites) are costly to maintain, are difficult to manipulate, and require considerable space. Our initial explorations centered on independently assessing the impacts of nematode, bacterium, and phage population densities on virus migration between host patches. Our results indicated that virus transmission increases with worm density and host bacterial abundance; however, transmission decreases with initial phage abundance, perhaps because viruses eliminate available hosts before migration can occur. We discuss the microbial growth dynamics that underlie these results, suggest mechanistic explanations for nematode transmission of phages, and propose intriguing possibilities for future research.

scholarly journals Calculation of the Optimum Cone Angle of a Confuser Used for Reversive-Jet Cleaning of Metal Surfaces against Corrosion

2019 ◽  
Vol 18 (3) ◽  
pp. 216-222
Author(s):  
I. V. Kachanov ◽  
A. N. Zhuk ◽  
I. M. Shatalov ◽  
V. V. Veremenyuk ◽  
A. V. Filipchik
Keyword(s):  
Metal Surfaces ◽  
Production Efficiency ◽  
Cone Angle ◽  
Experimental Studies ◽  
Raw Material ◽  
Flame Spraying ◽  
Working Fluid ◽  
Material Base ◽  
River Sand ◽  
Jet Impact

The modern industrial production of the Republic of Belarus is characterized by the absence of its own raw material base and significant dependence on imported energy carriers and material resources supplied at world prices. When working in such conditions, production efficiency can be achieved through all-round economy and creation of modern energyand resource-saving technologies. However implementation of such technologies, for example, laser cutting and welding, cladding, flame spraying, painting, etc. directly depends on quality of cleaning metal surfaces from corrosion. Theoretical and experimental studies conducted at the Department of Shipbuilding and Hydraulics of the Belarusian National Technical University have shown that it is very economical to remove corrosion products from metal surfaces using new technology of reverse jet cleaning. The reverse jet cleaning technology is based on a physical principle which presupposes that a jet of working fluid (pulp based on river sand or bentonite clay) rotates 180º when it hits the surface to be cleaned and it leads to an increase in jet impact on the surface to be cleaned by 1.5–2 times due to occurrence of a reactive component. In order to ensure a marked jet reversal an original case design has been developed which is characterized by a patent novelty. One of the main elements in this design is a confuser-shaped stream-forming device. Theoretical investigations on pressure losses of working fluid in a confuser channel which are based on the study of functional at the extremum have made it possible to obtain a dependence for calculation of an optimal cone angle at a turbulent mode of motion within the range of Reynolds numbers 4000 < Re < 3 ×106 while taking into account an influence of working fluid density, its dynamic or kinematic viscosity, average velocity movement of working fluid, confuser radii.

Effects of Platelet Size and Mean Volume Fraction on Platelet Orientation and Volume Fraction Distributions in Functionally Graded Material Fabricated by a Centrifugal Solid-Particle Method

2007 ◽  
Vol 129 (2) ◽  
pp. 304-312 ◽  
Author(s):  
P. D. Sequeira ◽  
Yoshimi Watanabe ◽  
Hiroyuki Eryu ◽  
Tetsuya Yamamoto ◽  
Kiyotaka Matsuura
Keyword(s):  
Solid Particle ◽  
Volume Fraction ◽  
Experimental Studies ◽  
Particle Method ◽  
Processing Parameters ◽  
Model System ◽  
Model Material ◽  
Functionally Graded ◽  
Formation Mechanisms ◽  
Graded Material

Background. A centrifugal solid-particle method has been successfully used as a means to fabricate functionally graded materials (FGMs). Various processing parameters significantly influence the formation of the graded microstructural and properties distribution in these FGMs. Method of Approach. Alloys with different Al3Ti platelet volume fractions and platelet sizes are used to study the effects of those parameters on graded distributions of the volume fraction and orientation of platelets. Al-platelet/plaster FGMs are used as a model system, and the effects of the same parameters are investigated. Results. It was found that an increase in initial volume fraction and particle size leads to steeper gradients of volume fraction and orientation distributions within the Al-Al3Ti FGMs. The results of the experimental studies are compared to those of the model material. Conclusions. It was verified that, although with some limitations, the proposed model system will be useful in the study of the formation mechanisms of the graded distributions in the FGMs.

scholarly journals Improving the engine power of a catalytic Janus-sphere micromotor by roughening its surface

2017 ◽  
Author(s):  
Brooke W. Longbottom ◽  
Stefan Bon
Keyword(s):  
Surface Area ◽  
Large Deformations ◽  
Experimental Studies ◽  
Model System ◽  
Catalytic Layer ◽  
Irregular Surface ◽  
Catalytic Surface ◽  
Surface Deformations ◽  
Propulsive Mechanism ◽  
Engine Power

<div> <div> <div> <p>Microspheres with catalytic caps have become a popular model system for studying self- propelled colloids. Existing experimental studies involve predominantly “smooth” particle surfaces. In this study we determine the effect of irregular surface deformations on the propulsive mechanism with a particular focus on speed. The particle surfaces were deformed prior to depositing a catalytic layer which resulted in the formation of nanoscopic pillars of catalyst. These features were shown to boost speed (~2×) when the underlying surface deformations are small (nanoscale), whilst large deformations afforded little difference despite a substantial apparent catalytic surface area. Colloids with deformed surfaces were more likely to display a mixture of rotational and translational propulsion than their “smooth” counterparts. </p> </div> </div> </div>

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