Ceiling impact on air disinfection performance of Upper-Room Germicidal Ultraviolet (UR-GUV).

This study used Computational Fluid Dynamics (CFD) to investigate air disinfection for SARS-CoV-2 by the Upper-Room Germicidal Ultraviolet (UR-GUV), with focus on ceiling impact. The study includes three indoor settings, i.e.

Toward a Test Protocol for Surface Decontamination Using a Mobile Whole-room UVGI Device.

Mobile whole-room UVGI devices are used in healthcare settings to control surface-borne pathogens. Unfortunately, no standard method comparing the efficacy of these devices is available. We accessed the effect of shadows on UVC 254 nm inactivation.

Surgical reconstruction of the ossicular chain with custom 3D printed ossicular prosthesis.

Background: Conductive hearing loss due to ossicular abnormalities occurs from many causes, including trauma, infection, cholesteatoma, surgery and congenital anomalies. Surgical reconstruction of the ossicular chain is a well-established procedure for repair of ossicular defects, but is still plagued by high failure rates. Underlying disease and proper sizing of prostheses are two challenges that lead to component failure.

Numerical Modeling of Indoor Environment with a Ceiling Fan and an Upper-Room Ultraviolet Germicidal Irradiation System.

This study proposes a numerical modeling method for the indoor environment with ceiling fans and upper-room ultraviolet germicidal irradiation (UR-UVGI) fixtures. The numerical modeling deployed steady-state Computational Fluid Dynamics (CFD) with a rotating reference frame to simulate the rotation of fan blades. CFD was validated with experimental data of velocity field and fraction of microorganism remaining at the exhaust diffuser.

Numerical investigation of upper-room UVGI disinfection efficacy in an environmental chamber with a ceiling fan.

This study investigated the disinfection efficacy of the upper-room ultraviolet germicidal irradiation (UR-UVGI) system with ceiling fans. The investigation used the steady-state computational fluid dynamics (CFD) simulations to solve the rotation of ceiling fan with a rotating reference frame. Two ambient air exchange rates, 2 and 6 air changes per hour (ACH), and four downward fan rotational speeds, 0, 80, 150 and 235 rpm were considered.

Ultraviolet germicidal irradiation safety concerns: a lesson from the Tuberculosis Ultraviolet Shelter Study: Murphy's Law affirmed.

Concerns about the safety of Ultraviolet Germicidal Irradiation (UVGI) applications on human beings have been an issue at least since the introduction of this technology for practical use in the 1930s. The resurgence of tuberculosis (TB) in the United States in the mid-1980s led to a revival of interest in UV technology, a focus that had almost disappeared because alternate means of controlling TB had inaccurately been deemed successful. These failures in TB control led to a revival of UVGI use.

Latent tuberculosis and active tuberculosis disease rates among the homeless, New York, New York, USA, 1992-2006.

We conducted a retrospective study to examine trends in latent tuberculosis infection (LTBI) and TB disease rates among homeless persons in shelters in New York, NY, 1992-2006. Although TB case rates fell from 1,502/100,000 population to 0, a 31% LTBI rate in 2006 shows the value of identifying and treating TB in the homeless.

Safety of upper-room ultraviolet germicidal air disinfection for room occupants: results from the Tuberculosis Ultraviolet Shelter Study.

Objectives: We evaluated the safety of room occupants in the Tuberculosis Ultraviolet Shelter Study (TUSS), a double-blind, placebo-controlled field trial of upper-room ultraviolet germicidal irradiation (UVGI) at 14 homeless shelters in six U.S. cities from 1997 to 2004.

Fundamental factors affecting upper-room ultraviolet germicidal irradiation - part I. Experimental.

The objective of this research was to study the factors that relate to the effectiveness of upper-room ultraviolet germicidal irradiation for inactivating airborne microorganisms. The work was conducted in a room-sized chamber designed and furnished for investigations of this nature. Nebulized Serratia marcescens, Bacillus subtilis spores, and vaccinia virus were used as test aerosols.

The application of ultraviolet germicidal irradiation to control transmission of airborne disease: bioterrorism countermeasure.

Bioterrorism is an area of increasing public health concern. The intent of this article is to review the air cleansing technologies available to protect building occupants from the intentional release of bioterror agents into congregate spaces (such as offices, schools, auditoriums, and transportation centers), as well as through outside air intakes and by way of recirculation air ducts. Current available technologies include increased ventilation, filtration, and ultraviolet germicidal irradiation (UVGI) UVGI is a common tool in laboratories and health care facilities, but is not familiar to the public, or to some heating, ventilation, and air conditioning engineers.