Impacts of cave air ventilation and in-cave prior calcite precipitation on Golgotha Cave dripwater chemistry, southwest Australia

Bioregional categorisation of the Australian marine environment is essential to conserve and manage entire ecosystems, including the biota and associated habitats. It is important that these regions are optimally positioned to effectively plan for the protection of distinct assemblages. Recent climatic variation and changes to the marine environment in Southwest Australia (SWA) have resulted in shifts in species ranges and changes to the composition of marine assemblages. The goal of this study was to determine if the current bioregionalisation of SWA accurately represents the present distribution of shallow-water reef fishes across 2000 km of its subtropical and temperate coastline. Data was collected in 2015 using diver-operated underwater stereo-video surveys from 7 regions between Port Gregory (north of Geraldton) to the east of Esperance. This study indicated that (1) the shallow-water reef fish of SWA formed 4 distinct assemblages along the coast: one Midwestern, one Central and 2 Southern Assemblages; (2) differences between these fish assemblages were primarily driven by sea surface temperature, Ecklonia radiata cover, non-E. radiata (canopy) cover, understorey algae cover, reef type and reef height; and (3) each of the 4 assemblages were characterised by a high number of short-range Australian and Western Australian endemic species. The findings from this study suggest that 4, rather than the existing 3 bioregions would more effectively capture the shallow-water reef fish assemblage patterns, with boundaries having shifted southwards likely associated with ocean warming.

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Forced-Air Ventilation for Sanitary Sewer Odor Control: What’s My Zone of Influence Going To Be?

Proceedings of the Water Environment Federation ◽

10.2175/193864716821124593 ◽

2016 ◽

Vol 2016 (4) ◽

pp. 472-489

Author(s):

Mark M Smith

Keyword(s):

Odor Control ◽

Sanitary Sewer ◽

Air Ventilation ◽

Zone Of Influence ◽

Forced Air

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Simplified biogeochemical numerical model to predict pore fluid chemistry and calcite precipitation during biocementation of soil

Arabian Journal of Geosciences ◽

10.1007/s12517-021-07151-x ◽

2021 ◽

Vol 14 (9) ◽

Author(s):

Meghna Sharma ◽

Neelima Satyam ◽

Nitin Tiwari ◽

Shubham Sahu ◽

Krishna R. Reddy

Keyword(s):

Numerical Model ◽

Pore Fluid ◽

Calcite Precipitation ◽

Fluid Chemistry ◽

Pore Fluid Chemistry

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Long-term association between urban air ventilation and mortality in Hong Kong

Environmental Research ◽

10.1016/j.envres.2021.111000 ◽

2021 ◽

Vol 197 ◽

pp. 111000

Author(s):

Pin Wang ◽

William B. Goggins ◽

Yuan Shi ◽

Xuyi Zhang ◽

Chao Ren ◽

...

Keyword(s):

Hong Kong ◽

Urban Air ◽

Air Ventilation

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Effects of Different Types of Fibers on the Physical and Mechanical Properties of MICP-Treated Calcareous Sand

Materials ◽

10.3390/ma14020268 ◽

2021 ◽

Vol 14 (2) ◽

pp. 268

Author(s):

Jitong Zhao ◽

Huawei Tong ◽

Yi Shan ◽

Jie Yuan ◽

Qiuwang Peng ◽

...

Keyword(s):

Mechanical Properties ◽

Water Absorption ◽

Glass Fiber ◽

Physical And Mechanical Properties ◽

Polyester Fiber ◽

Engineering Properties ◽

Fiber Types ◽

Calcite Precipitation ◽

Calcareous Sand ◽

Hemp Fiber

Microbial-induced calcite precipitation (MICP) has been a promising method to improve geotechnical engineering properties through the precipitation of calcium carbonate (CaCO3) on the contact and surface of soil particles in recent years. In the present experiment, water absorption and unconfined compressive strength (UCS) tests were carried out to investigate the effects of three different fiber types (glass fiber, polyester fiber, and hemp fiber) on the physical and mechanical properties of MICP-treated calcareous sand. The fibers used were at 0%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, and 0.40% relative to the weight of the sand. The results showed that the failure strain and ductility of the samples could be improved by adding fibers. Compared to biocemented sand (BS), the water absorption of these three fiber-reinforced biocemented sands were, respectively, decreased by 11.60%, 21.18%, and 7.29%. UCS was, respectively, increased by 24.20%, 60.76%, and 6.40%. Polyester fiber produced the best effect, followed by glass fiber and hemp fiber. The optimum contents of glass fiber and polyester fiber were 0.20% and 0.25%, respectively. The optimum content of hemp fiber was within the range of 0.20–0.25%. Light-emitting diode (LED) microscope and scanning electron microscope (SEM) images lead to the conclusion that only a little calcite precipitation had occurred around the hemp fiber, leading to a poor bonding effect compared to the glass and polyester fibers. It was therefore suggested that polyester fiber should be used to improve the properties of biocemented sand.

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Enhancing Air Quality for Embedded Hospital Germicidal Lamps

Sustainability ◽

10.3390/su13042389 ◽

2021 ◽

Vol 13 (4) ◽

pp. 2389

Author(s):

Jung-Shun Chen

Keyword(s):

Air Quality ◽

Hospital Staff ◽

Ventilation Rate ◽

Hospital Environment ◽

Design Stage ◽

Flow Noise ◽

Air Ventilation ◽

Air Disinfection ◽

Type 3

The indoor air of a hospital is always full of bacteria and viruses due to patients with different diseases. These bacteria and viruses could be highly infectious to the people in the hospital irrespective of their health conditions, and could be hazardous to the patients, their care takers, and hospital staff. Thus, keeping a good hospital air quality is very essential to the operation of the hospital. This study aims at enhancing ventilation of the interior lighting of hospitals with germicidal capabilities. Air disinfection is accomplished by adding the specially designed disinfecting filters and fans to existing embedded lamps in the hospitals. The embedded lamp has a square shape of 601 mm in width and 112 mm in thickness. In the design stage, the air flow inside the embedded lamp with the added filters and fans was investigated by numerical simulation using a computational fluid dynamics (CFD) tool. Three designs, referred to as Types 1, 2, and 3, were evaluated using steady-state CFD flow simulations. The ventilation rate of the Type 1 design was about 251.9 CMH, and 348.3 CMH for the Type 2 design by increasing the fan outlet area. However, even though the ventilation was increased by 34%, the flow field of the Type 2 design was not uniform, resulting in flows being circulated around the side locations. Thus, the Type 3 design further treats this aspect by streamlining the outlet geometry and adding flow guiding vanes to reduce flow resistance and flow unsteadiness; the corresponding air ventilation rate reached 376.3 CMH. Hence, the Type 3 design was fabricated and tested. The test results confirm that the design not only has a higher ventilation rate but also operates under a smaller pressure drop, thus accomplishing the goal of providing good air quality in the hospital environment efficiently. Moreover, the associated flow noise is reduced by about 8 dBA. Hence, both an increase in the air ventilation rate and a reduction of noise are achieved simultaneously by the present method.

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Air Ventilation Performance of School Classrooms with Respect to the Installation Positions of Return Duct

Sustainability ◽

10.3390/su13116188 ◽

2021 ◽

Vol 13 (11) ◽

pp. 6188

Author(s):

Sungwan Son ◽

Choon-Man Jang

Keyword(s):

Air Quality ◽

Numerical Analysis ◽

Indoor Air Quality ◽

Indoor Air ◽

Three Dimensional ◽

Cross Infection ◽

School Students ◽

Height Range ◽

Air Ventilation ◽

Ventilation Performance

For students, who spend most of their time in school classrooms, it is important to maintain indoor air quality (IAQ) to ensure a comfortable and healthy life. Recently, the ventilation performance for indoor air quality in elementary schools has emerged as an important social issue due to the increase in the number of days of continuous high concentrations of particulate matter. Three-dimensional numerical analysis has been introduced to evaluate the indoor airflow according to the installation location of return diffusers. Considering the possibility of the cross-infection of infectious diseases between students due to the direction of airflow in the classroom, the airflow angles of the average respiratory height range of elementary school students, between 1.0 and 1.5 m, are analyzed. Throughout the numerical analysis inside the classroom, it is found that the floor return system reduces the indoor horizontal airflow that causes cross-infection among students by 20% compared to the upper return systems. Air ventilation performance is also analyzed in detail using the results of numerical simulation, including streamlines, temperature and the age of air.

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