scholarly journals Behavior Characteristics of Hazardous Gas and Scattering Coal Dust in Coal Storage Sheds

2021 ◽  
Vol 11 (24) ◽  
pp. 11771
Author(s):  
Mok-Lyang Cho ◽  
Ji-Soo Ha ◽  
Tae-Kwon Kim
Keyword(s):  
Carbon Monoxide ◽  
Natural Ventilation ◽  
Coal Dust ◽  
Retaining Wall ◽  
Ventilation System ◽  
Spontaneous Ignition ◽  
Flow Stagnation ◽  
Measurement Results ◽  
Behavior Characteristics ◽  
And Behavior

This study has comprehensively analyzed the ventilation system of an indoor coal storage shed using computational fluid dynamics (CFD). In addition, the effects of the plan to improve the ventilation system were investigated by synthesizing the results. First, the velocity of inlet wind entering through the natural ventilation system was measured. Then, the concentration of carbon monoxide inside the coal storage shed was measured at the spontaneous combustion of coal. The boundary conditions were set using the measurement results. The characteristics of carbon monoxide concentration, ventilation volume, and behavior of scattering dust were analyzed. According to the CFD analysis results, the upper recirculation strength increased as the flow rate of external air increased. The flow-stagnation area occurred on the center wall. In particular, the concentration of carbon monoxide was high in the flow-stagnation area. When the inflow velocity was 2.0 m/s, a risk of 30 ppm or more occurred in the area near the second-floor workspace and central retaining wall. When ventilation dropped sharply, coal dust emissions decreased to 14.5%. Thus, ventilation must be secured by installing a natural ventilation system, in case spontaneous ignition occurs in many cells or the ventilation sharply decreases. Finally, in order to improve the ventilation system, the effect on the additional installation of natural ventilation and the use of mobile blowers was analyzed. Finally, in order to improve the ventilation system, the effect on the additional installation of natural ventilation and the use of mobile blowers was analyzed. As a result of the analysis, we concluded that using a mobile blower is more effective than a method of additionally installing a natural ventilation device. Carbon monoxide may be locally diluted, and ventilation volume additionally secured.

Ventilation strategy for random pollutant releasing from rubber vulcanization process

2016 ◽  
Vol 26 (2) ◽  
pp. 248-255 ◽  
Author(s):  
Changsheng Cao ◽  
Jun Gao ◽  
Yumei Hou ◽  
Jie Chen
Keyword(s):  
Production Process ◽  
Ventilation System ◽  
Primary Source ◽  
Emission Characteristic ◽  
Ventilation Strategy ◽  
Exhaust Hood ◽  
Cumulative Emission ◽  
Measurement Results ◽  
Vulcanization Process ◽  
Source Emission

This paper investigates the emission characteristic of a rubber vulcanization process in a workshop and tries to formulate a ventilation strategy for the rubber vulcanization production process with a lower exhaust rate. Measurements were performed to derive detailed source emission characteristic of rubber vulcanization process in a rubber workshop. The measurement results show that the primary source emission process was concentrated within 600 s of a vulcanization process, the corresponding cumulative emission percentage reached up to 95%. Based on random pollutant releasing from rubber vulcanization process, a single local exhaust hood was applied for a curing machine, the corresponding exhaust rate of 4000 m3/h was proven to be reliable for capturing rubber fume by the experimental and numerical methods. The corresponding cumulative capture efficiency of the single local exhaust hood was 92.1% at 600 s. A new ventilation system equipped with single local exhaust hood was further designed for the rubber vulcanization production process line, and the total exhaust rate of this system was only a quarter of the original one used in a large exhaust hood system. These findings have illustrated that the new ventilation system equipped with single local exhaust hood could largely reduce the exhaust rate in a rubber vulcanization workshop.

Low Emissions Kit Development for a 1.5MW EMD GP20D Locomotive

2015 ◽  
Author(s):  
Christopher R. Stoos ◽  
Alexander Guliaeff
Keyword(s):  
Carbon Monoxide ◽  
Fuel Injection ◽  
Ventilation System ◽  
Exhaust Emission ◽  
Injection Timing ◽  
Engine Operation ◽  
Temperature Oxidation ◽  
Diesel Particulate ◽  
Diesel Particulate Filters ◽  
Particulate Filters

This paper describes the development, testing, and application of a low emissions upgrade kit for 1.5 MW EMD GP20D locomotives. Low emissions development focused on changes to fuel injection timing combined with the application of crank case ventilation system (CCV) and catalyzed diesel particulate filters (DPF). Composed of a porous cordierite ceramic material, the diesel particulate filters are specifically designed for entrapment of diesel particulates while allowing exhaust gases to flow through. Furthermore, the filters are coated with a proprietary catalyzed washcoat that promotes the oxidation of soot within the exhaust gas temperature range observed under normal engine operation. In addition to the low temperature oxidation of soot, the catalyzed filter also reduces carbon monoxide and unburned hydrocarbons. The test locomotive used for this development, which is owned by CIT Rail, was powered by a recently rebuilt Caterpillar 3516B engine with a rated power of 1.5 MW (2,000 HP). Baseline exhaust emission testing was performed, followed by low emissions retrofit development. In combination with the CCV and new fuel injection calibrations, the DPF system netted significant emissions reductions. The result of the final low emissions upgrade kit was an EPA Tier 1+ certification, with emissions levels that were below EPA Tier 3 locomotive switch cycle standards for oxides of nitrogen (NOx) and below EPA Tier 4 switch cycle standards for hydrocarbons (HC), carbon monoxide (CO), particulate matter (PM), and smoke.

scholarly journals Relationship between Entrepreneurial Team Characteristics and Venture Performance in China: From the Aspects of Cognition and Behaviors

2020 ◽  
Vol 12 (1) ◽  
pp. 377 ◽  
Author(s):  
Xue-Liang Pei ◽  
Tung-Ju Wu ◽  
Jia-Ning Guo ◽  
Jia-Qi Hu
Keyword(s):  
Structural Equation ◽  
Equation Modeling ◽  
Team Cognition ◽  
Team Members ◽  
Research Results ◽  
Venture Performance ◽  
Entrepreneurial Team ◽  
Behavior Characteristics ◽  
And Behavior ◽  
The Relationship

Entrepreneurial and innovative activities are becoming a global economic and social phenomenon, especially in emerging economies. This study focuses on a typical emerging economy, China, and its entrepreneurial and innovative activities. On the basis of current research, the literature review and the chain of “cognition–behavior–outcome” are used for constructing the theoretical model for the relationship among entrepreneurial team cognition characteristics, behavior characteristics, and venture performance. A total of 101 valid copies of questionnaire are collected from entrepreneurial team members, as the research objects, and the structural equation modeling (SEM) method is applied to test the theoretical hypotheses. The research results reveal (1) significant effects of entrepreneurial team cognition characteristics and behavior characteristics on venture performance and (2) partial mediating effects of entrepreneurial team behavior characteristics on the relationship between cognition characteristics and venture performance. The research results are the expansion of research on entrepreneurial teams as well as the important reference for entrepreneurial team management and behavioral practice.

scholarly journals Three-Dimensional Simulation of Wind-Driven Ventilation Through a Windcatcher With Different Inlet Designs

2019 ◽  
Vol 12 (4) ◽  
Author(s):  
Peter Abdo ◽  
Rahil Taghipour ◽  
B. Phuoc Huynh
Keyword(s):  
Wind Speed ◽  
Average Velocity ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Three Dimensional ◽  
Cfd Modeling ◽  
Ansys Fluent ◽  
Wind Velocities ◽  
Dimensional Simulation ◽  
Convergent Inlet

Abstract Windcatcher is an effective natural ventilation system, and its performance depends on several factors including wind speed and wind direction. It provides a comfortable and healthy indoor environment since the introduced fresh air decreases the moisture content and reduces the pollutant concentration. Since the wind speed and its direction are generally unpredictable, it is important to use special inlet forms and exits to increase the efficiency of a windcatcher. In this study, computational fluid dynamics (CFD) modeling is implemented using ansys fluent to investigate the airflow entering a three-dimensional room through a windcatcher with different inlet designs. Three designs are studied which are a uniform inlet, a divergent inlet, and a bulging-convergent inlet. The airflow pattern with all inlets provided adequate ventilation through the room. With all the applied wind velocities (1, 2, 3, and 6 m/s) at the domain's inlet, the divergent inlet shape has captured the highest airflow through the room and provided higher average velocity at 1.2 m high enhancing the thermal comfort where most of the human occupancy occurs. With 6 m/s wind velocity, the divergent inlet has captured 2.55% more flow rate compared to the uniform inlet and 4.70% compared to the bulging-convergent inlet, and it has also provided an average velocity at 1.2 m high in the room of 7.16% higher than the uniform inlet and 8.44% higher than the bulging-convergent inlet.

scholarly journals In vitro growth of Cattleya nobilior Rchb. f.: culture media, sealing systems and irradiance

2021 ◽  
Vol 51 ◽  
Author(s):  
Kaliana Gottschalk de Freitas ◽  
José Carlos Sorgato ◽  
Jackeline Schultz Soares ◽  
Luan Marlon Ribeiro
Keyword(s):  
Plant Height ◽  
Natural Ventilation ◽  
Culture Medium ◽  
Culture Media ◽  
Ventilation System ◽  
Light Condition ◽  
Leaf Length ◽  
In Vitro Growth ◽  
Randomized Design

ABSTRACT Some factors may influence the in vitro culture of native orchids, especially the culture medium, sealing system and light condition. This study aimed to evaluate the addition of banana pulp and peel in the formulation of culture media, sealing system and irradiance, in the in vitro growth of Cattleya nobilior Rchb. f. A completely randomized design was used in a factorial scheme with five culture media [Murashige & Skoog supplemented or not with banana pulp or peel (100 or 200g L-1)], two light conditions [3,000 K LED lamps (43 µmol m-2 s-1 or 86 µmol m-2 s-1)] and two sealing systems (natural and conventional ventilation), with six replicates of one vial each. The plant height, diameter of the largest pseudobulb, length of the largest root and of the largest leaf, fresh weight and number of leaves, roots and shoots were evaluated. The use of both the banana pulp and peel as additives in the culture medium formulation promoted the C. nobilior growth. The natural ventilation system increased the plant height, pseudobulb diameter and leaf length, while the conventional system promoted tillering.

An Attempt to Improve Air Quality in Primary Schools

2017 ◽  
Author(s):  
Marek Telejko ◽  
Ewa Zender-Swiercz
Keyword(s):  
Air Quality ◽  
Primary School ◽  
Indoor Air ◽  
Primary Schools ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Co2 Concentration ◽  
School Buildings ◽  
Maximum Value

Most primary school buildings in Poland rely on natural ventilation. This fact is attributed to the age of these buildings constructed more than dozen or even several tens of years ago. Few of them were fitted with a mechanical ventilation system allowing for the adjustment of microclimate parameters. The national requirements for gravity ventilation provide general guidelines, specifying strict description only for the airtightness of windows and doors and the minimum airflow to be supplied to the rooms. The minimum airflow supplied is independent of the number of occupants and purpose of the room. Low indoor air quality (IAQ) can impact occupants’ health and lead to poor productivity or low academic performance. Therefore the provision of good IAQ in classrooms and laboratories is very important. This paper presents the results of the investigation devoted to the quality of indoor air in classrooms of selected Polish primary school. Six primary school in a town with a population of 200 000 inhabitants were involved in the investigations. The participating school buildings were built between 1976 and 1994 and had gravity ventilation systems. The variability of basic IAQ parameters, i.e., temperature, relative humidity and carbon dioxide level, was analysed and the assessment of the classrooms in terms of microbiological purity was performed. The outcomes confirmed the low quality of the indoor air in these buildings. The maximum value of CO2 concentration amounted to more than 4000 ppm. Certain modifications aimed at improving IAQ were proposed during the investigations. Two solutions were implemented. The results of this study indicate that the proposed solution offers the potential to improve IAQ within classrooms.

Sign in / Sign up

Export Citation Format

Share Document