scholarly journals Comparative evaluation of measured and perceived indoor environmental conditions in naturally and mechanically ventilated office environments

2020 ◽  
Vol 13 (5) ◽  
pp. 1021-1042
Author(s):  
Rajat Gupta ◽  
Alastair Howard
Keyword(s):  
Environmental Conditions ◽  
Comparative Evaluation ◽  
Mechanically Ventilated ◽  
Office Environments

scholarly journals Investigating the relationship between indoor environment and workplace productivity in naturally and mechanically ventilated office environments

2019 ◽  
Vol 41 (3) ◽  
pp. 280-304
Author(s):  
Rajat Gupta ◽  
Alastair Howard ◽  
Sahar Zahiri
Keyword(s):  
Environmental Conditions ◽  
Indoor Environment ◽  
Low Cost ◽  
Environmental Parameters ◽  
Working Environment ◽  
The Other ◽  
Mechanically Ventilated ◽  
Workplace Productivity ◽  
Office Environments ◽  
The Relationship

This paper uses a case study-based approach to empirically investigate the relationship between indoor environment and workplace productivity in two contrasting office environments: one naturally ventilated, the other mechanically ventilated. Environmental parameters were continuously monitored over 19 months. Transverse and longitudinal surveys recorded occupants’ perception of their working environment and self-reported productivity, while performance tasks (numerical and proofreading) measured cognitive capability as proxy for measured productivity. Indoor temperatures and CO2 concentrations were found to be higher and more variable in the naturally ventilated office. However, the correlation between occupant perception of their indoor environment and perceived productivity was stronger in the mechanically ventilated office. Occupants of the naturally ventilated office were found to be more tolerant of their environment than their counterparts in the mechanically ventilated office. Task performance was affected by indoor environmental conditions such as indoor temperature and CO2 concentration. Interestingly in the naturally ventilated office, the median scores were up to 12% higher for tests conducted at CO2 concentrations <1400 ppm, compared to those conducted above 1400 ppm, whereas in the mechanically ventilated office, this threshold was only 1000 ppm. The study showed that higher concentrations of CO2 were associated with lower task scores and longer task durations, reinforcing the need for good levels of ventilation in workspaces. It was found that occupants in NV workspaces were able to adapt to a broader range of environmental conditions. Therefore, controlling the indoor environment within narrow ranges (expending significant amounts of energy in the process) may not always be necessary to improve comfort and productivity. On the other hand, controlling indoor environment within a narrow range – as is common in MV workspaces – may be counterproductive, creating occupants who are less tolerant of small changes in their environmental conditions. The study also demonstrates occupant surveys can provide useful feedback on perceived comfort and productivity at relatively low cost. Insights from such surveys can be used to improve indoor environment in workspaces.

Single-Channel Speech Enhancement Techniques for Distant Speech Recognition

2013 ◽  
Vol 22 (2) ◽  
pp. 81-93
Author(s):  
Jaya Kumar Ashwini ◽  
Ramaswamy Kumaraswamy
Keyword(s):  
Speech Recognition ◽  
Impulse Response ◽  
Speech Enhancement ◽  
Environmental Conditions ◽  
Speech Signal ◽  
Single Channel ◽  
A Priori ◽  
Humanoid Robots ◽  
Intelligent Home ◽  
Office Environments

AbstractThis article presents an overview of the single-channel dereverberation methods suitable for distant speech recognition (DSR) application. The dereverberation methods are mainly classified based on the domain of enhancement of speech signal captured by a distant microphone. Many single-channel speech enhancement methods focus on either denoising or dereverberating the distorted speech signal. There are very few methods that consider both noise and reverberation effects. Such methods are discussed under a multistage approach in this article. The article concludes with a hypothesis that the methods that do not require an a priori reverberation impulse response is desirable in varying the environmental conditions for DSR applications such as intelligent home and office environments, humanoid robots, and automobiles rather than the methods that require an a priori reverberation impulse response.

Comparative Evaluation of Biofilm Formation and Tolerance to a Chemical Shock of Pathogenic and Nonpathogenic Escherichia coli O157:H7 Strains

2009 ◽  
Vol 72 (1) ◽  
pp. 157-164 ◽  
Author(s):  
N. MAROUANI-GADRI ◽  
D. CHASSAING ◽  
B. CARPENTIER
Keyword(s):  
Escherichia Coli ◽  
Stainless Steel ◽  
Environmental Conditions ◽  
Parental Strain ◽  
Biofilm Formation ◽  
Comparative Evaluation ◽  
Culture Medium ◽  
Escherichia Coli O157 ◽  
Medium Temperature ◽  
Model Strain

Seven Escherichia coli O157:H7 strains, three pathogenic (including epidemic EDL933 and Sakai) and four nonpathogenic (including mutants of EDL933 and Sakai), were compared to find a model strain to avoid the use of European third-class biological agents in biofilm studies. Comparison was performed on attached populations reached at the end of growth in eight environmental conditions defined as the combinations of three two-level factors: (i) culture medium composed of meat exudate and glucose-supplemented minimal salts medium (MSM), (ii) growth temperatures of 15 and 25°C, and (iii) materials of stainless steel and polyurethane. The influence of each of these four factors (strain, medium, temperature, and material) often depended on the level of at least one of the others. Exudate produced attached populations that were larger than or similar to those obtained with MSM, except for EDL933 mutant at 15°C. When exudate led to larger populations than did MSM, the highest differences of up to 1.8 log CFU/cm2 were observed with the nonepidemic strains grown at 25°C. Populations of these strains were not significantly different in any of the conditions studied, but they were different from the epidemic strains in some conditions. No nonpathogenic mutant was representative of its parental strain. Furthermore, the Sakai mutant biofilm was significantly more reduced than its parental strain was after chemical shock. It is therefore not possible to find a surrogate of either EDL933 or Sakai, and it is advisable that main results be validated on a pathogenic strain whenever nonpathogenic strains are used.

scholarly journals Effect of environmental conditions on fire combustion regimes in mechanically-ventilated compartments

2021 ◽  
pp. 103493
Author(s):  
Hugues Prétrel ◽  
Nathaly Chaaraoui ◽  
Bouaza Lafdal ◽  
Sylvain Suard
Keyword(s):  
Environmental Conditions ◽  
Mechanically Ventilated ◽  
Combustion Regimes

scholarly journals Comparative evaluation of ventilator-associated pneumonia in critically ill COVID- 19 and patients infected with other corona viruses: a systematic review and meta-analysis

2021 ◽  
Author(s):  
Shikha Jain ◽  
Puneet Khanna ◽  
Soumya Sarkar
Keyword(s):  
Critically Ill ◽  
Comparative Evaluation ◽  
Meta Analysis ◽  
Invasive Mechanical Ventilation ◽  
Rapid Review ◽  
Ventilator Associated Pneumonia ◽  
Mechanically Ventilated ◽  
Increased Risk ◽  
Prisma Statement ◽  
Corona Viruses

The Coronavirus disease 19 (COVID-19) pandemic is associated with an unprecedented requirement for intensive care unit (ICU) admission, invasive mechanical ventilation, and thereby significantly increasing the risk of secondary nosocomial pneumonia, Ventilator-Associated Pneumonia (VAP). Our study aims to identify the overall incidence of VAP, common organisms associated with it, and outcome in COVID-19 patients in comparison to the non-SARS-CoV-2 infected critically ill ventilated COVID-19 patients. A comprehensive screening was conducted using major electronic databases), from January 1st 2020 to May 31st 2021, as per the PRISMA statement. In our rapid review, we included a total of 34 studies (involving 8901 cases. Overall VAP was reported in 48.15 % (95% CI 42.3%-54%) mechanically ventilated COVID-19 patients and the mortality rate was 51.4% (95% CI 42.5%-60%). COVID-19 patients had increased risk of VAP and mortality in comparison to other non-SARS-CoV-2 viral pneumonia (OR=2.33; 95%CI 1.75-3.11; I2=15%, and OR=1.46; 95%CI 1.15-1.86; I2=0% respectively). Critically ill COVID-19 patients are prone to develop VAP, which worsens the outcome.

Vibration Isolator System for Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 182-183
Author(s):  
K. Ohi ◽  
M. Mizuno ◽  
T. Kasai ◽  
Y. Ohkura ◽  
K. Mizuno ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Magnetic Fields ◽  
Environmental Conditions ◽  
Vibration Isolator ◽  
Air Conditioners ◽  
Vibration Isolators ◽  
Large Size ◽  
Electron Microscopes

In recent years, with electron microscopes coming into wider use, their installation environments do not necessarily give their performance full play. Their environmental conditions include air-conditioners, magnetic fields, and vibrations. We report a jointly developed entirely new vibration isolator which is effective against the vibrations transmitted from the floor.Conventionally, large-sized vibration isolators which need the digging of a pit have been used. These vibration isolators, however, are large present problems of installation and maintenance because of their large-size.Thus, we intended to make a vibration isolator which1) eliminates the need for changing the installation room2) eliminates the need of maintenance and3) are compact in size and easily installable.

Sign in / Sign up

Export Citation Format

Share Document