Dynamics and Numerical Simulation of Contaminant Diffusion for a Non-Flushing Ecological Toilet

The poor indoor air quality (IAQ) of severely polluted toilets is associated with increased risk of severe disease. This study aimed to evaluate the overall IAQ according to the contaminant removal efficiency, volume average concentration, and breathing zone control level. The characteristics of contaminant transmission in a non-flushing ecological toilet (NFET) were analyzed using the computational fluid dynamics (CFD) methodology, and the proposed model was further validated based on experimental measurements. Both an orthogonal experimental design and CFD were used to analyze factors such as exhaust fan position (EFP), air change rate per hour (ACH), natural vent location (NVL), and grid height (G-h). The EFP and ACH were demonstrated to be the dominant factors affecting the IAQ, whereas NVL and G-h were found to play key roles. Single-factor analysis based on the significance levels of the ACH, EFP, and NVL was conducted using the CFD methodology to define three exhaust behaviors—namely, “ineffective”, “enhanced”, and “excessive”. These results provide key insights that may be used to improve the IAQ of NFETs.

Modeling and analysis of the states of objects and subjects of monitoring by means of secure sensor networks and IoT networks with a supercomputer

The paper proposes an information technology for evidence-based monitoring of the states of remote and mobile objects and subjects. The proposed method for the effective implementation of long-term monitoring of a large number of objects based on modeling information states of objects by means of aperture or zone control of changes in selected indicators and calculated signal characteristics. Taking into account the minimization of computations with performance-limited processor facilities of the object systems of secure wireless monitoring networks at the places of introduction of monitoring signals, it is proposed to form logical and statistical information models of the behavior of objects that correspond to the current functional and operating states of objects of long-term monitoring. To identify the most informative signals and characteristics of the states of objects, it is proposed to calculate and analyze the relative and normalized indicators and characteristics of signals. Information technology is focused on long-term monitoring of objects and subjects in various spheres of human activity.

Nitric Oxide Emission Reduction in Reheating Furnaces through Burner and Furnace Air-Staged Combustions

In this study, a series of experiments were conducted on a testing facility and a real-scale furnace, for analyzing the nitric oxide (NO) emission reduction. The effects of the temperature, oxygen concentration, and amount of secondary combustion air were investigated in a single-burner combustion system. Additionally, the NO-reduction rate before and after combustion modifications in both the burner and furnace air-staged combustion were evaluated for a real-scale reheating furnace. The air-to-fuel equivalence ratio (λ) of individual combustion zones for the furnace was optimized for NO reduction without any incomplete combustion. The results indicated that the NO emission for controlling the λ of a single-zone decreased linearly with a decrease in the λ values in the individual firing tests (top-heat, bottom-heat, and bottom-soak zones). Moreover, the multi-zone control of the λ values for individual combustion zones was optimized at 1.13 (top-preheat), 1.0 (bottom-preheat), 1.0 (top-heat), 0.97 (bottom-heat), 1.0 (top-soak), and 0.97 (bottom-soak). In this firing condition, the modifications reduced the NO emissions by approximately 23%, as indicated by a comparison of the data obtained before and after the modifications. Thus, the combined application of burner and furnace air-staged combustions facilitated NO-emission reduction.