Search results

This study aims to examine on-site particle concentration levels due to emissions from a wide spectrum of additive manufacturing techniques, including polymer-based material extrusion, metal and polymer-based powder bed fusion, directed energy deposition and ink-based material jetting.

Particle concentrations in the operating environments of users were measured using a combination of particle sizers including the TSI 3910 Nano SMPS (10–420 nm) and the TSI 3330 optical particle sizer (0.3–10 µm). Also, fumes from a MEX printer during printing were directly captured using laser imaging method.

The number and mass concentration of submicron particles emitted from a desktop open-type MEX printer for acrylonitrile-butadiene-styrene and polyvinyl alcohol approached and significantly exceeded the nanoparticle reference limits, respectively. Through laser imaging, fumes were observed to originate from the printer nozzle and from newly deposited layers of the desktop MEX printer. On the other hand, caution should be taken in the pre-processing of metal and polymer powder. Specifically, one to ten micrometers of particles were observed during the sieving, loading and cleaning of powder, with transient mass concentrations ranging between 150 and 9,000 µg/m³ that significantly exceeded the threshold level suggested for indoor air quality.

Preliminary investigation into possible exposures to particle emissions from different 3D printing processes was done, which is useful for the sustainable development of the 3D printing industry. In addition, automatic processes that enable “closed powder cycle” or “powder free handling” should be adopted to prevent users from unnecessary particle exposure.

This study aims to investigate the effect of trisodium nitrilotriacetic acid (NTA) on the physical and luminescence emission properties of NaLuF4:Yb, Tm Upconversion (UC) particles and compared with trisodium citrate (CA). Upconversion materials have been remarkably considered in many applications in the past decades. However, the morphology of the UC particles affects their emission properties, depending on the synthesis situation.

The UC particles were synthesized by the hydrothermal method. Properties such as crystal phase, particle morphology, particle size, smoothness and uniformity of particle surface and their emission intensity in the UV–Vis region were studied.

Observations showed that pH is an essential factor in determining the crystalline phase. In addition, quality factors affect the morphology, particle size and surface smoothness of crystalline facets. It was also found that the UC particles synthesized in the presence of trisodium NTA have a much higher emission intensity than those synthesized in the presence of CA. The use of UC particles in security inks to maintain the brand was also investigated.

To the best of the authors’ knowledge, for the first time, the effect of trisodium NTA as a chelating agent was investigated on morphology and UC intensity of NaLuF4:Yb,Tm phosphor.

Because domestic heating appliances have the advantage of reducing emissions of greenhouse gas, their use is greatly increased and is largely recommended by European governments. However, some recent studies revealed that residential wood stoves and inserts are the source of many chemicals in the form of gases (CO₂, CO, SO₂, NO_x), volatile organic compounds (alkane, alkenes, benzene, etc. …) and tars (mainly constituting poly‐aromatic hydrocarbons). The most important of them in terms of the emission factor and impact on environment and human health are carbon monoxide and fine particles. The aim of this study is to test the activity of a Pd‐based catalyst on the reduction of gas and particles during wood combustion in a domestic fireplace.

A catalytic system, placed at the exit of the fireplace, was developed to reduce pollutants. Pollutant characterization of a domestic fireplace from FONDIS SA, according to two paces of functioning (nominal and low‐charge), was performed with and without the presence of the catalyst. Fine and ultrafine particle distributions were characterized using an Electrical Low Pressure Impactor.

The presence of a catalyst drastically decreases the emission factors of CO. Though performing efficiently with respect to the total suspended particles emission factor, it does not significantly affect the emission factors of aerosols. Nevertheless, in the presence of the catalyst, air supply conditions slightly modify size distributions of PM0.1 to PM10.

A purification assembly, having catalysts for gases and combustion fumes from solid fuel heating apparatus, was patented and fireplaces are now commercially available from FONDIS SA.

This work was an adaptation of the catalytic system present in the automotive Diesel exhaust engines. It was not necessary to consult previous laboratory experiments in order to perform its activity because it was directly tested at the duct fireplace.

Smoke and dust emissions from industrial furnaces can do great harm to the environment and human health. This paper aims to analyze the morphology, diameter and elements of the submicron particles from the furnace flues and the nearby ambient air by using two typical industrial furnaces, the sintering furnace and the electric furnace.

Two typical industrial furnaces, the sintering furnace and the electric furnace, were chosen in this study, to analyze the morphology, diameter and elements of the submicron particles from the furnace flues and the near-by ambient air.

The results show that the particles from the two furnaces are mainly in the small sizes of 0.3-0.6 μm. Particles from sintering plant flue are mainly spherical and rich in K and Cl, whereas those from the electric plant flue are mainly particles rich in metal elements, such as Zn and Fe, and have different morphology.

The particles in the atmosphere nearby the two furnaces contain aged particles from the flue, lots of spherical particles, rectangle particles and various aggregations. The elements of those particles are complex.

The aim of the paper is to present the results of investigations of fine particle generation by small biomass combustion and the possibility of reducing the emissions by electrostatic precipitation.

The grains, wood‐logs, wood‐, mixed‐ and straw‐pellets were combusted in two stoves and two boilers. The set‐ups were operated according to DIN‐4702. Particle number concentration in the gas flow was measured by Scanning Mobility Particle Sizer and particle mass concentration was measured according to the Guidelines VDI‐2066 upstream and downstream a novel space charge electrostatic precipitator (ESP). The ESP consists of an ioniser and a grounded brush inside of a tube form grounded collector electrode.

The ESP ensures stable operation at gas temperatures up to 350°C. The use of sharp‐points high voltage electrode ensures effective particle charging at high particle number concentrations. The combustion of wood‐pellets is characterized by lower particle mass concentrations. The highest particle mass concentrations were observed by the straw‐pellets combustion. The ESP ensures particle collection with mass collection efficiency 87±3% for wood‐logs and 82±2% for wood‐pellets combustion.

The novel ESP is recommended for exhaust gas cleaning from small scale biomass combustion facilities and domestic heating units. The use of the ESP would reduce the emissions of fine aerosol into the atmosphere and improve the air quality.

The paper presents the comparative analysis of particle size distribution and particle mass concentrations in the exhaust gas from small‐scale combustion units for different types of biomass. The study confirms the possibility to reduce particle emissions by electrostatic precipitation. The originality of the technology and apparatus is patently protected.

This paper aims to measure exposures to airborne contaminants during three-dimensional (3-D) printing and post-processing tasks in an industrial workplace.

Contaminant concentrations were assessed using real-time particle number (0.007 to 1 µm) and total volatile organic compound (TVOC) monitors and thermal desorption tubes during various tasks at a manufacturing facility using fused deposition modeling (FDM^TM) 3-D printers. Personal exposures were measured for two workers using nanoparticle respiratory deposition samplers for metals and passive badges for specific VOCs.

Opening industrial-scale FDM^TM 3-D printer doors after printing, removing desktop FDM^TM 3-D printer covers during printing, acetone vapor polishing (AVP) and chloroform vapor polishing (CVP) tasks all resulted in transient increases in levels of submicrometer-scale particles and/or organic vapors, a portion of which enter the workers’ breathing zone, resulting in exposure. Personal exposure to quantifiable levels of metals in particles <300 nm were 0.02 mg/m³ for aluminum, chromium, copper, iron and titanium during FDM^TM printing. Personal exposures were 0.38 to 6.47 mg/m³ for acetone during AVP and 0.18 mg/m³ for chloroform during CVP.

Characterization of tasks provided insights on factors that influenced contaminant levels, and in turn exposures to various particles, metals < 300 nm and organic vapors. These concentration and exposure factors data are useful for identifying tasks and work processes to consider for implementation of new or improved control technologies to mitigate exposures in manufacturing facilities using FDM^TM 3-D printers.

The eastern Ukrainian city of Mariupol is among the most polluted cities in the Ukraine. Even with a decrease in manufacturing after the dissolution of the USSR, the high amounts of hazardous wastes in the water, air and soil have not been reduced, often exceeding the safety limits used by the World Health Organisation (WHO). City dwellers continue to have worryingly short lifespans, as well as a high percentage of oncological diseases. The current extent of the problems seen in the city is described in this paper, along with a programme aimed at the sustainable development of the city. Public discussions of Mariupol’s environmental problems are documented in this paper and took place via workshops, newspaper articles, television programmes and surveys. As a result of these investigations, increasing life expectancy by ten years was chosen as the primary goal for city development. A summary of the project is presented, along with some analysis and recommendations.

Basing himself on the premise that present economic progress cannot follow the ‘Business as usual paradigm’ and hope for continued and unlimited progress, the author holds that we need to look into the larger dimensions of growth and development, which include social, environmental and other complex factors. So in this chapter, the author makes some pertinent suggestions for a sustainable growth model inspired by green growth and degrowth.

The first section evaluates the salient features of green growth and its drawbacks. It is followed by a discussion on the notion of degrowth, with its challenge to change the direction of growth (economic, ecological, social and cultural), without which human civilisation, as we know it today, may not survive. Finally, in the concluding chapter, based on these two notions of green growth and degrowth, an all-inclusive and sustainable regrowth model is propounded.

By creating an awareness of the need to shift development goals and Corporate Social Responsibility (CSR), the author argues that we could use economic regrowth strategically and responsibly to make the world more sustainable and viable. Responsible corporates will make their contribution to such an organic, resilient and sustainable regrowth and their CSR activities could be the starting point for this change, without which humanity's future is seriously threatened.

Finally, the author acknowledges that humanity has profited from the tremendous technological and economic progress we have made in the last four centuries, learnt from its mistakes and are ready to reorient ourselves individually and collectively towards a sustainable economic regrowth.