Biological Monitoring Incorporated (United States)

Research on the effect of fire on bridge structures is still an area that has received little attention by the structural engineering community. In cases where bridges have been exposed to fire, the need to quickly ascertain, re-open or replace the afflicted structure has limited detailed investigation of the effects of fire exposure. A modeling investigation on the behavior of bridges when exposed to simulated fires will be presented in this work. A modeling methodology was developed to integrate the fire dynamics simulation with a finite element model of the structural response. The discussion will cover the use of the Fire Dynamics Simulator in conjunction with the finite element software ABAQUS. The modeling methodology developed was utilized to simulate several fire scenarios with different parameters such as fire size and location altered. It was found that tanker fuel trucks were the only vehicle large enough to cause permanent deflections in the simulated events.

Exposure of bridge structures to fire is a seldom-investigated area of bridge analysis and design. It has yet to be addressed on a national or international design code. The spectacle of these incidents and their potential for damage to bridge structures has lead to a call to further investigate the sources, frequency and effects of fires that threaten bridge structures. The results of a statistics investigation, case study analysis and literature review will be presented. The statistic study used data available in several national database maintained by agencies such as the NHTSA and FEMA. The three sources of statistics on bridge fire events returned similar results of fire occurrences in a year.

Thermophilic enzymes are in high demand for various applications due to their prolonged lifetimes and high reaction rates at elevated temperatures. In this work, an open reading frame TM0295, which encodes a putative transaldolase (TAL) from a hyper-thermophilic microorganism, Thermotoga maritima, was cloned and expressed in Escherichia coli. The enzyme activity of transaldolase at high temperatures (e.g., at 80 °C) was reported here for the first time. The recombinant T. maritima transaldolase was extremely thermostable, with a half-life time of 198 and 13.0 h at 60 °C and 80 °C, respectively. The estimated total turn-over number was 1.5 × 10(6) mol of product per mol of enzyme at 80 °C. This enzyme also exhibited high activities within a broad pH range of 6.0-9.0. This ultra-thermostable TAL with high activity shows great potential for use in such applications as the production of enzymatic biofuels production and the synthesis of high-value carbohydrates by cell-free synthetic pathway biotransformation.

To the Editor:We recently reported (1) urinary ethyl glucuronide (EtG) and ethyl sulfate (EtS) concentrations in subjects intensively exposed to an ethanol-containing hand sanitizer under a controlled research protocol.We concluded that dermal exposure to ethanol can result in urinary EtG concentrations exceeding commonly accepted thresholds for substance abuse recovery programs that require abstinence from ethanol use.In our report, we acknowledged that inhalation of vaporized ethanol during use of the hand sanitizer may contribute to absorption; however, the experiment was not designed to assess the relative contributions of dermal versus respiratory ethanol exposure.An unpublished study by Gregory E. Skipper and colleagues suggested that inhalation was the primary mechanism by which ethanol is absorbed when using ethanol-containing hand sanitizers, and when this study was brought to our attention, we re-evaluated the potential that our study design may have overestimated the exposure to ethanol because of accumulation of ethanol vapor in the study environment.The study was conducted in a conference room with dimensions of approximately 20 ft × 30 ft × 10 ft.Subjects were seated in chairs arranged peripherally around a "U"-shaped table in the center of the room.Space was sufficient for the subjects to be separated by at least a meter.The room was air conditioned, and double doors were open at all times to an exterior hallway.In our calculations, we sought to estimate the maximal exposure to ethanol vapor assuming a 6000 ft 3 closed room with no air exchange, 100% evaporation of ethanol (no dermal absorption), and the ethanol contained in 11 1-mL doses of a 61% ethanol-containing hand sanitizer distributed equally throughout the volume of the room.Additionally, we assumed that subjects inspired 16 times per minute and that 100% of the inspired ethanol was absorbed.Under those assumptions, accumulated respiratory exposure to ethanol over 120 cycles during each study day (subjects cleansed their hands every 5 min for 10 h) for each subject was approximately 192 mg of ethanol.If we further assume that 100% of the inspired ethanol vapor is absorbed, conversion to EtG is 0.1% (2), and urinary output is approximately 1 L per day, then ethanol vapor would account for less than 200 ng/mL urinary EtG concentration, which was far less than the maximum urinary EtG we measured (2001 ng/mL) in our subjects.Urinary EtS concentrations in our study subjects were insignificant.The assumptions we have made maximize the potential exposure to ethanol vapor from other subjects participating in the study.Proximal ethanol vapor concentrations were certainly higher than what this model predicts, but they do not negate our findings that intensive use of ethanol-containing hand sanitizers can produce significant concentrations of urinary EtG.The question of whether ethanol absorption resulting from the use of hand sanitizers is primarily dermal or respiratory is only important if the circumstances favor one over the other.In our study, we do not believe that ethanol vapor contributed significantly to ethanol exposure or urinary EtG concentrations.

Abstract Diffusion of acetone at the interface of a bonded pressure sensitive adhesive tape was measured using single frequency capacitance measurements (SFCM) and a novel interdigitated electrode sensor design. The relative concentration of acetone at the bondline as a function of distance from the edge of the specimen and exposure time was correlated to adhesion loss measured by the 90° peel test. This work suggests that these novel sensors are applicable for the study of interfacial diffusion processes, and could be extended to other coatings or adhesives in a variety of environments.

In spite of extensive study and efforts to improve business ethics and increase corporate social responsibility, a quick review of almost any business publication will show that breaches of ethics are a common occurrence in the business community. In this paper we explore reasons for potential discrepancies or gaps between organizational and individual ethical standards, the consequences of such discrepancies, and possible methods of reducing the detrimental effects of these differences. The concept of self-leadership, as constructed through social learning theory is examined, and shown to be a potentially valuable tool for employees' use in making reasoned decisions in varying organizational ethical climates. Specifically, the authors will show how the practice of self-leadership can be employed as an important means to improve moral action within the firm.

Over a 2-year period, an industrial discharger implemented a program to determine if there was a potential for in-stream impact from its discharge, and, if necessary, to eliminate that potential. Six basic study designs were used. These included: (1) ambient toxicity tests using indicator organisms; (2) in-stream waste concentration (IWC) chronic testing using indicator organisms; (3) on-site flow-through toxicity testing using indicator and resident species with receiving stream water as the diluent; (4) in situ acute toxicity studies using indicator and resident species; (5) biological surveys of the receiving stream; and (6) artificial stream studies. The outcome of the studies resulted in conclusive data on which to base the design of a diffuser to dilute the effluent 1:20. This concentration was well below the lowest acute no-observed-effect concentration (10% effluent) determined using sensitive resident test species. In this manner, impact from the effluent on the James River had been reduced so that even the most sensitive resident species were protected. As a result of the study, the facility's permit was modified so that toxicity tests were made only on effluent diluted with receiving stream water to represent dilution at 1Q10 rather than 100 percent effluent. Follow-up studies have concentrated on a series of toxicity tests which were designed to identify the toxicants in the final effluent.