scholarly journals Biofilm Cohesive Strength as a Basis for Biofilm Recalcitrance: Are Bacterial Biofilms Overdesigned?

2015 ◽  
Vol 8s2 ◽  
pp. MBI.S31444 ◽  
Author(s):  
Srijan Aggarwal ◽  
Philip S. Stewart ◽  
Raymond M. Hozalski
Keyword(s):  
Factor Of Safety ◽  
Cohesive Strength ◽  
Bacterial Biofilms ◽  
Experimental Measurements ◽  
Bacterial Inactivation ◽  
Engineering Structures ◽  
Biophysical Aspect

Bacterial biofilms are highly resistant to common antibacterial treatments, and several physiological explanations have been offered to explain the recalcitrant nature of bacterial biofilms. Herein, a biophysical aspect of biofilm recalcitrance is being reported on. While engineering structures are often overdesigned with a factor of safety (FOS) usually under 10, experimental measurements of biofilm cohesive strength suggest that the FOS is on the order of thousands. In other words, bacterial biofilms appear to be designed to withstand extreme forces rather than typical or average loads. In scenarios requiring the removal or control of unwanted biofilms, this emphasizes the importance of considering strategies for structurally weakening the biofilms in conjunction with bacterial inactivation.

scholarly journals Inactivation efficacy of atmospheric air plasma and airborne acoustic ultrasound against bacterial biofilms

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Apurva D. Patange ◽  
Jeremy C. Simpson ◽  
James F. Curtin ◽  
Catherine M. Burgess ◽  
P. J. Cullen ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Bacterial Biofilm ◽  
Bacterial Biofilms ◽  
Primary Role ◽  
Bacterial Cells ◽  
Bacterial Inactivation ◽  
Air Plasma ◽  
Atmospheric Air ◽  
Environment And Health ◽  
Ultrasound Technology

AbstractBiofilms are complex microbial communities that present serious contamination risks to our environment and health. In this study, atmospheric air plasma and airborne acoustic ultrasound technology were applied to inactivate Escherichia coli and Listeria innocua biofilms. Both technologies were efficient in controlling, or completely inactivating, the target bacterial biofilms. Viability and metabolic assays, along with microscopy analysis, revealed that atmospheric air plasma and airborne acoustic ultrasound damaged both the bacterial biofilm cells and its structural integrity. Scanning electron microscopy images highlighted the disruption of the biofilms and pore formation in bacterial cells exposed to both the plasma and acoustic treatments. Elevated reactive oxygen and nitrogen species in bacterial cells treated with atmospheric air plasma, demonstrated their primary role in the observed bacterial inactivation process. Our findings provide potential antimicrobial strategies to combat bacterial biofilms in the food and healthcare sectors.

scholarly journals Multi-layer composite mechanical modeling for the inhomogeneous biofilm mechanical behavior

2016 ◽  
Vol 14 (04) ◽  
pp. 1650014 ◽  
Author(s):  
Xiaoling Wang ◽  
Jingshi Han ◽  
Kui Li ◽  
Guoqing Wang ◽  
Mudong Hao
Keyword(s):  
Composite Model ◽  
Bacterial Biofilms ◽  
Alternative Theory ◽  
Experimental Measurements ◽  
Mechanical Modeling ◽  
Biofilm Thickness ◽  
Simulation Procedure ◽  
Element Simulation ◽  
Layer Composite ◽  
Multiple Component

Experiments showed that bacterial biofilms are heterogeneous, for example, the density, the diffusion coefficient, and mechanical properties of the biofilm are different along the biofilm thickness. In this paper, we establish a multi-layer composite model to describe the biofilm mechanical inhomogeneity based on unified multiple-component cellular automaton (UMCCA) model. By using our model, we develop finite element simulation procedure for biofilm tension experiment. The failure limit and biofilm extension displacement obtained from our model agree well with experimental measurements. This method provides an alternative theory to study the mechanical inhomogeneity in biological materials.

scholarly journals Safety Criteria and Standards for Bearing Capacity of Foundation

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Yanlong Li ◽  
Wangtao Fan ◽  
Xuguang Chen ◽  
Yunhe Liu ◽  
Bo Chen
Keyword(s):  
Bearing Capacity ◽  
Safety Factor ◽  
Reliability Index ◽  
Factor Of Safety ◽  
Safety Margin ◽  
Engineering Structures ◽  
Evaluation Standards ◽  
Factor Method ◽  
Reliability Based Design ◽  
Target Reliability Index

This paper focuses on the evaluation standards of factor of safety for foundation stability analysis. The problem of foundation stability is analyzed via the methods of risk analysis of engineering structures and reliability-based design, and the factor of safety for foundation stability is determined by using bearing capacity safety-factor method (BSFM) and strength safety-factor method (SSFM). Based on a typical example, the admissible factors of safety were calibrated with a target reliability index specified in relevant standards. Two safety criteria and their standards of bearing capacity of foundation for these two methods (BSFM and SSFM) were established. The universality of the safety criteria and their standards for foundation reliability was verified based on the concept of the ratio of safety margin (RSM).

Lighting of Engineering Structures and Industrial Facilities New Aspects of the Topic

2018 ◽  
pp. 29-36
Author(s):  
Nikolai I. Shepetkov ◽  
George N. Cherkasov ◽  
Vladimir A. Novikov
Keyword(s):  
Fundamental Problem ◽  
Lighting Design ◽  
Aesthetic Value ◽  
Engineering Structures ◽  
Industrial Facilities ◽  
Artificial Lighting ◽  
Industrial Structures ◽  
Design Solutions ◽  
Architectural Lighting ◽  
The Aesthetic

This paper considers the fundamental problem of artificial lighting in various types and scales of industrial facilities, focusing on exterior lighting design solutions. There is a lack of interest from investors, customers and society in high­quality lighting design for industrial facilities in Russia, which in many cities are very imaginative structures, practically unused in the evening. Architectural lighting of various types of installations is illustrated with photographs. The purpose of the article is to draw attention to the aesthetic value of industrial structures, provided not only by the architectural, but also by a welldesigned lighting solution.

Finite Element Simulation of Tire-Rim Interface

1989 ◽  
Vol 17 (4) ◽  
pp. 305-325 ◽  
Author(s):  
N. T. Tseng ◽  
R. G. Pelle ◽  
J. P. Chang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Finite Element Simulation ◽  
Contact Pressure ◽  
Element Model ◽  
Experimental Measurements ◽  
Inflation Pressure ◽  
Interference Fit ◽  
Element Simulation ◽  
Rubber Composite

Abstract A finite element model was developed to simulate the tire-rim interface. Elastomers were modeled by nonlinear incompressible elements, whereas plies were simulated by cord-rubber composite elements. Gap elements were used to simulate the opening between tire and rim at zero inflation pressure. This opening closed when the inflation pressure was increased gradually. The predicted distribution of contact pressure at the tire-rim interface agreed very well with the available experimental measurements. Several variations of the tire-rim interference fit were analyzed.

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