Papers by Keyword: Exposure

Abstract: Covid-19 is a highly contagious aero-transmissible virus. Even after two years of its emergence, new strains appear that require strengthening security measures such as social distancing, the use of masks, etc. It is crucial to prevent contamination, and care for the sanity of the air in closed environments, occupied by two or more people. Aerosols expelled by contaminated individuals dissolve in environments and can contaminate individuals regardless of their location. In this project, an air purifier for individual use was proposed to mitigate the risk of contamination by Covid-19 in closed environments. The equipment has been developed and prototyped, but has yet to be presented in the scope of this article. In this phase of the project, a study was conducted through numerical simulation to understand the effect of using this purifier on air circulation and its scope in the environment. Nine scenarios were developed: five two-dimensional and four three-dimensional, subject to different conditions: (i) closed environment, (ii) air infiltration through doors and windows, (iii) air-conditioner use, and purifier use. In individual use of the purifier, even if it is approximately 50 cm from the person in the room, the curtain of “clean air” coming from the purifier has become ineffective due to the existence of another, more intense outlet. The scenario with the airflow from the air-conditioner showed that the higher intensity of the airflow compared to the prototype purifier's airflow, meant that the prototype's airflow could not protect the user from the theoretically contaminated air mixed in the room. When the simulation of the use of the purifier was not done together with the air-conditioner runoff, the purifier proved effective in providing clean air and "protecting" the user with a wind curtain. However, even when the purified air cannot directly protect the user, the effects of the purifier can be beneficial by reducing the contamination of the air in the room as a whole (with a flow rate of 0.016 m3/s or 57.6 m3/h), and potentially reducing the chances of virus infection.

Abstract: This study was measured the concentration level of contamination by DEHP on indoor flooring surfaces. It was confirmed that vacuum-cleaning of dust accumulated on flooring surfaces would not completely eliminate DEHP in the flooring. Unlike ceilings or walls, children are more prone to come in direct contact with flooring; meaning children’s bare skin is more likely to be exposed to high-concentration of DEHP on flooring surfaces. As children lick their hands that come in direct contact with the flooring, their chance of orally ingesting DEHP is likely to increase as well. Given these findings, it is considered important to assess children’s exposure to DEHP in indoor environments and assess the risks thereof by investing the subject in relation to behavioral characteristics of children.

Abstract: The paper presents a theoretical and practical approach to the concept of risk assessment of exposure to noise, specific to activity for use of pyrotechnic articles Category 4, from the perspective of ensuring the security of the effect resulting after fireworks displaying with these types of pyrotechnic products. For estimation and risk assessment using these types of products, researches has been undertaken to make an evaluation process procedure in order to provide data and information to prevent and combat the causes that may create a hazard.

Abstract: Noise – as a risk factor in the environment – in case it exceeds the intensity limits it becomes a biological aggression factor, a medical and social contaminant with implications of prime importance in terms of health, work capacity and comfort.This research is an objective analysis of noise level and frequency spectrum emitted by gas compressor Compressco CJ 360 in order to identify and develop solutions for noise protection required for the establishment of the environmental conditions in accordance with legal regulations in the area desired by the beneficiary. The research proposes a technical solution for closing the compressor with sound insulation prior to placing it in the desired place, in suitable environmental conditions.

Abstract: Environmental tobacco smoke (ETS), also known as second-hand smoke (SHS), is a complex mixture of chemicals generated during the burning and smoking of tobacco products. Smoking has become the most important indoor air pollutant source in China in terms of human health. The paper firstly analyzed the health effects of environmental tobacco smoke, the conditions of the environmental tobacco smoke exposure in recent years, and environmental impact of environmental tobacco smoke. The exposure to ETS that has influence on human heath, specially the women and children is the important risk factor. Meantime, the ETS exposure rate in the crowd has risen in recent years, and the public places, workplaces and families that pose the ETS exposure are the main sites. Second-hand smoke severely impact on the indoor air quality, especially it is the most important pollutant source of indoor air PM2.5. The exposure to Environmental Tobacco Smoke (ETS) does severe harm not only to the people’s lives and health, but also to social economic development in China. Finally, the paper put up with some suggestions to control environmental tobacco smoke in China.

Abstract: Acetylcholinesterase (AChE) is the enzyme that controls the acetylcholine (ACh) concentrations in cholinergic synaptic clefts by hydrolyzing ACh to choline and acetate. In this paper, we investigate the effect of very low frequency (VLF) electromagnetic field (EMF) radiation on AChE activity. AChE was exposed to VLF-EMFs with electric field intensity ranged from 0 to 200V/m and exposure time ranged from 0 to 120min. The results demonstrated that the VLF-EMF increased enzyme activity when the intensity ranged from 80V/m to 100V/m as well as exposure time ranged from 60min to 80min. And the AChE activity decreased when the intensity ranged from 120V/m to 140V/m and exposure time ranged from 20min to 120min. Thus, those results are significant in clinical treatments.

Abstract: The diamond impregnated bit matrix should not only wrap the diamond up firmly; also constantly wear in the drilling process to ensure that the diamond can be made exposure constantly. The wear of diamond impregnated bit matrix is the key to affect the exposure of diamond blade.In this paper, based on the tribology, the wear mechanism of drill bits matrix is analysed from the microscopic view.Then,the relationship between matrix hardness and abrasion resistance can be obtained.

Abstract: Flexographic printing plate based on its soft characteristic has been widely used in the field of printing of corrugated box and plastic film. The system researches on the factors influencing the flexographic platemaking quality were carried out, including the different exposure time and the different development time affected the bulge image depth and plate thickness of the printing plate. The results provided a reliable reference data to obtain excellent printed matter, which determined the ideal platemaking parameters of the same type plate without doing any experiment.

Abstract: Diurnal variations and personal exposure of carbonyl compounds were investigated in four types of large shopping malls (including department store, supermarket, bookstore and furniture store) in urban district of Nanchang, China. The diurnal measurements both in the summer and winter showed that the concentrations of carbonyls exhibited a higher peak at the morning hour and a lower peak at the evening hour except for acetaldehyde, which obviously peaked at the afternoon hour in winter. The indoor concentrations of LMW carbonyl compounds were found higher than their outdoor counterparts with only a few exceptions. For some high molecular weight (HMW) carbonyls (C₅) especially for benzaldehyde and p-Tolualdehyde which might have stronger outdoor source (e.g. vehicle exhaust), resulting in the Indoor/Outdoor ratios below 1. The personal exposures showed that large shopping malls in Nanchang were important microenvironment for exposure to formaldehyde and acetaldehyde.

Abstract: Lead is unique in that man-made sources contribute almost solely to exposure in the post-industrial era.The adverse health effects caused by low-level exposure to Pb have been reviewed. Such health effects include neurological impairment and deficits in the functioning of the central nervous system. Blood lead level is an important index which can measure how seriously children have been exposed to lead. By consulting the papers on the studies of children’s blood lead levels, the sources and influencing factors of blood lead levels of children in China were reviewed in the present paper, meanwhile, some suggestions were provided to decrease the lead contact probability and improve children’s health.