Dynamic Vapor Generator That Simulates Transient Odor Emissions of Victims Entrapped in the Voids of Collapsed Buildings

Abstract

The design, development, and validation of a dynamic vapor generator are presented. The generator simulates human scent (odor) emissions from trapped victims in the voids of collapsed buildings. The validation of the device was carried out using a reference detector: a quadrupole mass spectrometer equipped with a pulsed sampling (PS-MS) system. A series of experiments were conducted for evaluating the simulator's performance, defining types and weights of different factors, and proposing further optimization of the device. The developed device enabled the production of stable and transient odor profiles in a controllable and reproducible way (relative standard deviation, RSD < 11%) at ppbv to low ppmv concentrations and allowed emission durations up to 30 min. Moreover, the factors affecting its optimum performance (i.e., evaporation chamber temperature, air flow rate through the mixing chamber, air flow rate through the evaporation chamber, and type of compound) were evaluated through an analysis of variance (ANOVA) tool revealing the next steps toward optimizing the generator. The developed simulator, potentially, can also serve the need for calibrating and evaluating the performance of analytical devices (e.g., gas chromatographers, ion mobility spectrometers, mass spectrometers, sensors, e-noses) in the field. Furthermore, it can contribute in better training of urban search and rescue (USaR) canines.

Experimental and Analytical Analysis of Macro-Scale Molecular Communications Within Closed Boundaries

“…To analyze closed boundary transmission and its effect on the propagation and signal delay, an experimental setup was created. To generate and to transmit the particles, an odor transmitter was developed [28], [30], [47]- [49]. To detect the sent particles and distinguish them, a membrane inlet mass spectrometer with a quadrupole mass analyzes (QMA) was used.…”

“…A study conducted in [28] showed an experimental transmission of closed-boundary experiment. However, the [47] (1) Carrier gas (Q) introduction into the mixing chamber (2) Mixing chamber (3) Evaporation chamber ( Figure 3) (4) Transmitted chemicals that are released from the chamber. (5) A modulation sequence that is used to create gas pulses [30].…”

Analysis of Multi-Chemical Transmission in the Macro-Scale

“…The first part consists of mass flow controllers (MFC) which depending on the message going to be transmitted, closes and releases the valves which control the flow of the N 2 gas. This controlled gas then travels to the evaporation chamber (EC) where the evaporated chemicals in the chamber is carried over to the mixing chamber [34], [36]. For the experiment, volatile organic compounds (VOCs) are used.…”

Design and Implementation of a Gas Generating System for Complex Gas Mixtures and Calibration Gases

“…Thus, it is crucial to perform multiple calibration points using the same concentrations, but at various levels of RH%. For gas streams containing mixtures of trace concentrations, the divided dilution flow is superior compared to the direct injection . Here, the water vapor is mixed with the highest flow rate gas stream (dilution gas).…”