scholarly journals Microbiological Evaluation of a Range of Disinfectant Products To Control Mixed-Species Biofilm Contamination in a Laboratory Model of a Dental Unit Water System

2003 ◽  
Vol 69 (6) ◽  
pp. 3327-3332 ◽  
Author(s):  
J. T. Walker ◽  
D. J. Bradshaw ◽  
M. R. Fulford ◽  
P. D. Marsh
Keyword(s):  
Active Agent ◽  
Water System ◽  
Cost Effective ◽  
Laboratory Model ◽  
Mixed Species ◽  
Biofilm Model ◽  
Viable Bacteria ◽  
Sufficient Reduction ◽  
Multispecies Biofilms ◽  
Image Analysis Techniques

ABSTRACT Dental unit water system (DUWS) tubing harbors complex multispecies biofilms that are responsible for high microbial levels at the distal outlet. The aim of this study was to use an established biofilm laboratory model to simulate biofouling of DUWS to evaluate practical, cost-effective, and evidence-based methods of microbial decontamination. Reproducible biofilms were developed in the model over 14 days; decontamination was assessed using total viable counts (TVC) and microscopic-image analysis techniques to view the inner surface of tubing. Flushing did not reduce the biofilm coverage or TVC. Combizyme and ozone did not completely eliminate the viable bacteria (70 and 65% reduction in biofilm TVC, respectively), nor did they remove the biofilm (45 and 57% reduction in biofilm coverage, respectively). Chlorhexidine and Bio2000 (active agent: ethanol and chlorhexidine), Tegodor and Gigasept Rapid (aldehyde based), and Grotanol (hydroxide based) completely eliminated the TVC but did not completely remove biofilm (31, 53 33, 34, and 64.9% reduction of biofilm coverage, respectively). Other products including Grotanol Flussig (phenol based), Betadine (povidone-iodine based), Alpron (chlorite based), and the hydroxide-containing products Sporklenz, Sterilex Ultra, Dialox, Sterilox, Sanosil, Oxigenal, and Grotanat Bohrerbad resulted in a 100% reduction in the biofilm TVC and a >95% reduction in biofilm coverage. The study demonstrated that while many disinfectants achieve a sufficient reduction in TVC they may not necessarily remove unwanted biofilm from the tubing surfaces as tested in this laboratory-controlled biofilm model.

Effect of Mixed-Species Biofilm on Copper Surfaces in Cooling Water System

2014 ◽  
Vol 24 (2) ◽  
pp. 848-858 ◽  
Author(s):  
Nihal Doğruöz Güngör ◽  
Ayşın Çotuk ◽  
Esra Ilhan-Sungur ◽  
Nurhan Cansever
Keyword(s):  
Water System ◽  
Cooling Water ◽  
Mixed Species ◽  
Copper Surfaces ◽  
Cooling Water System

scholarly journals H∞BASEDOBSERVER FOR DISTURBANCE COMPENSATION IN DECOUPLED TRMS USING LMI OPTIMIZATION

2014 ◽  
pp. 213-218
Author(s):  
LEKSHMI S ◽  
JEEVAMMA JACOB
Keyword(s):  
Disturbance Rejection ◽  
Control Method ◽  
Mimo System ◽  
Cost Effective ◽  
Laboratory Model ◽  
Disturbance Compensation ◽  
Lmi Optimization ◽  
Twin Rotor Mimo System ◽  
Model Inverse ◽  
Twin Rotor

Twin Rotor MIMO System is a laboratory model of helicopter. In this paper, the problem of disturbance rejection in TRMS is dealt with. Using disturbance observers, without any additional sensors is an attractive method to attenuate the effects of disturbances as they are highly cost effective. This method uses a simple form of DOBs, which does not need to solve the plant model inverse, and uses H∞control method using LMIs to design the Q-filter in the DOB. The estimation capability of DOB is verified using simulation results in frequency domain as well as in time domain.

Research at the Building Research Establishment into the applications of solar collectors for space and water heating in buildings

1980 ◽  
Vol 295 (1414) ◽  
pp. 403-414
Keyword(s):  
Solar Collector ◽  
Water System ◽  
Cost Effective ◽  
Heating System ◽  
Field Studies ◽  
Hot Water ◽  
Solar Collectors ◽  
Water Heating ◽  
Actual Performance ◽  
Low Efficiency

A completed study of a solar hot water heating system installed in a school showed an annual average efficiency of 15%, the low efficiency largely caused by the unfavourable pattern of use in schools. Field studies, in 80 existing and 12 new houses, of a simple domestic hot water system have been initiated to ascertain the influence of the occupants on the actual performance of solar collector systems. The development of testing methods of solar collectors and solar water heating systems is being undertaken in close collaboration with the B.S.I. and the E.E.C. Solar space heating is being investigated in two experimental low energy house laboratories, one using conventional solar collectors with interseasonal heat storage and the other a heat pump with an air solar collector. Studies of the cost-effectiveness of solar collector applications to buildings in the U.K. show that they are far less cost-effective than other means of conserving energy in buildings.

Assessing cost‐effective nutrient removal solutions in the urban water system

2020 ◽  
Vol 49 (3) ◽  
pp. 534-544 ◽  
Author(s):  
Brock Hodgson ◽  
Tyler Dell ◽  
Sybil Sharvelle ◽  
Mazdak Arabi
Keyword(s):  
Nutrient Removal ◽  
Water System ◽  
Cost Effective ◽  
Urban Water ◽  
Urban Water System

Effect of Inorganic Ions on Biofilms Component and Activity in the Recirculating Cooling Water System

2012 ◽  
Vol 512-515 ◽  
pp. 2287-2290
Author(s):  
Fang Liu ◽  
Fei Yang Wang ◽  
Chang Feng Liang ◽  
Wen Wen Dong ◽  
Jia Quan Zhang ◽  
...  
Keyword(s):  
Dehydrogenase Activity ◽  
Extracellular Polymeric Substances ◽  
Water System ◽  
Cooling Water ◽  
Inorganic Ions ◽  
Laboratory Model ◽  
Obvious Effect ◽  
Ion Concentrations ◽  
Inorganic Ion ◽  
Cooling Water System

In this research a laboratory model recirculating cooling water system was applied to investigate the effects of four kinds of inorganic ion concentrations on extracellular polymeric substances (EPS) content, the ration of proteins and polysaccharides ratio in EPS (PR/PS) and dehydrogenase activity (DHA) in the attached biofilms. The results showed that the low Na+ concentration was beneficial to EPS production and biofilms DHA. With Ca2+ concentration increasing, EPS content first increased and then decreased as a whole. Mg2+ showed no obvious effect on biofilms EPS content, while had the effect on PR/PS and DHA. The increase of Fe3+ concentration was beneficial for EPS formation and DHA when Fe3+ concentration was below 1.5 mg/L.

scholarly journals Differential oxidative stress tolerance ofStreptococcus mutansisolates affects competition in an ecological mixed‐species biofilm model

2017 ◽  
Vol 10 (1) ◽  
pp. 12-22 ◽  
Author(s):  
Yuan Liu ◽  
Sara R. Palmer ◽  
Hsiaochi Chang ◽  
Ashton N. Combs ◽  
Robert A. Burne ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Tolerance ◽  
Mixed Species ◽  
Oxidative Stress Tolerance ◽  
Biofilm Model

scholarly journals The HF “Fluoride-Ion” Cleaning Technique for Superalloys

1987 ◽  
Author(s):  
Louis F. Pochet ◽  
Alfred L. Clavel
Keyword(s):  
Process Control ◽  
Hydrogen Fluoride ◽  
Active Agent ◽  
Cost Effective ◽  
Fluoride Ion ◽  
Safe Handling ◽  
Cost Effective Method ◽  
Comparative Information

Fluoride-ion cleaning, using Hydrogen Fluoride gas as the active agent, is rapidly becoming established as a cost effective method to prepare nickel and cobalt based superalloys for braze repair. Background and comparative information on the four basic processes currently in use are discussed. The latest process using hydrogen fluoride gas directly is described in detail including the methods used for precise process control and safe handling of the HF input gas, as well as the off-gas fluoride compounds. Alloys successfully prepared for braze repair are listed. Other uses for the process and potential uses for the manufacture of new components are suggested.

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