scholarly journals The Measurement of Wood in Construction Dust Samples: A Furnace Based Thermal Gravimetric Approach

2019 ◽  
Vol 63 (9) ◽  
pp. 1070-1080
Author(s):  
Peter Stacey ◽  
Andrew Simpson ◽  
Susan Hambling
Keyword(s):  
Mineral Dust ◽  
Limit Of Detection ◽  
Rietveld Method ◽  
Gravimetric Method ◽  
Wood Dust ◽  
Thermal Gravimetric ◽  
Construction Sites ◽  
Quartz Fibre ◽  
Median Proportion ◽  
Inhalable Dust

Abstract A furnace-based thermal gravimetric method was developed to measure wood in inhalable construction dust. The application of this method showed that reliance on the inhalable concentrations alone may substantially overestimate carpenters’ exposures to wood dust at construction worksites. Test samples were prepared by collecting aerosols of gypsum, calcite, quartz, concrete, and wood dust onto quartz fibre filters using the Button inhalable sampler. The average difference between the measured and loaded mass of wood is 2% over the whole analytical range. Ninety percent of thermogravimetric measurements on all test samples (n = 35) were 13% or less. The limit of detection was measured as 0.065 mg. The thermal gravimetric method was applied to samples collected from four new build construction sites and one shop fitting worksite. The workplace inhalable wood dust results ranged from 15% to 104% of the total inhalable dust values. In addition, an x-ray diffraction (XRD) Rietveld method was applied as a complimentary approach to explain the composition of the remaining inhalable dust. Most combined thermal gravimetric and XRD measurements were within 10% of the total inhalable dust mass values, determined gravimetrically. Ninety-five percent were within 26%. The median proportion of mineral dust containing gypsum, calcite, quartz, dolomite, or rutile was 30%. The proportion of mineral dust on individual filters varied considerably.

A study to assess the performance of an “X-ray powder diffraction with Rietveld” approach for measuring the crystalline and amorphous components of inhalable dust collected on aerosol sampling filters

2019 ◽  
Vol 34 (3) ◽  
pp. 251-259 ◽  
Author(s):  
P. Stacey
Keyword(s):  
Rietveld Method ◽  
Internal Standard ◽  
Relative Difference ◽  
Wood Dust ◽  
Aerosol Sampling ◽  
Amorphous Content ◽  
Quartz Fibre ◽  
External Standard Method ◽  
External Standard ◽  
Inhalable Dust

This work was undertaken in preparation for a survey to assess the exposure of carpenters to hazardous dust working in construction. Inhalable dust, in this industry, was expected to contain both crystalline mineral and amorphous phases (wood dust). The Rietveld method was applied to provide a simultaneous multicomponent analysis. To assess its performance, mixtures of aerosolised calcite, gypsum, quartz, kaolinite, and wood dust were collected onto quartz fibre filters (n = 41) using the Button inhalable sampler. Results obtained using Rietveld were compared with loaded mass and those from external standard calibrations. The measured content of a component in 14 samples was used as an internal standard by Rietveld to determine amorphous content (wood). The performance of the Rietveld and external standard methods was similar. The 95% confidence interval for the absolute differences between the two methods was 15%. Only one relative difference of more than 15% had a mass loading >0.5 mg. An approach for assessing the limits of detection with relative intensity ratios was applied and gave comparable values with the usual method using calibration coefficients from the external standard method. Rietveld is therefore a potentially useful multicomponent method for the measurement of dust aerosol to help better understand workers' exposures.

Reliability of the measurement method in determining the mass concentration of hardwood dust

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 643-654
Author(s):  
Anka Ozana Čavlović ◽  
Ivan Bešlić ◽  
Željka Zgorelec ◽  
Josip Ožegović
Keyword(s):  
Mass Concentration ◽  
Measurement Method ◽  
Limit Of Detection ◽  
Ambient Air ◽  
Sampling Time ◽  
Wood Dust ◽  
Limit Of Quantification ◽  
Inhalable Dust ◽  
Personal Sampling

The reliability of the measurement method in determining the mass concentration of wood dust relates to the sampling time for the detection of wood particles in the ambient air of woodworking places. The aim of this study was to calculate the mass limit of detection (LOD), limit of quantification (LOQ), and the minimal sampling time (tLOD and tLOQ) for determination and quantification of samples, based on the hardwood dust mass concentration at various woodworking places in the sawmills, floor production factories, and carpentries. Determination of the mass concentration of respirable, inhalable, and total hardwood dust from ambient air was performed using personal sampling pumps and three types of filter holders: respirable dust cyclone, Institute of Occupational Medicine IOM inhalable dust sampler, and total dust open-faced filter holder. The average limit of detection amounts to 0.052, 0.083, and 0.167 mg for respirable, inhalable, and total hardwood dust, respectively. The minimal detection sampling time for collecting all observed types of dust fractions ranged between 1.12 h and 1.72 h. The minimal quantification time for all collected hardwood dust samples ranged from 3.75 h to 5.51 h. Pearson’s correlation test showed that the reliability of the measurements was affected more by the dustiness of the workspace than the real sampling time.

scholarly journals Total Fat Gravimetric Method Workflow in Portuguese Olives Using Closed-Vessel Microwave-Assisted Extraction (MAE)

Foods ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2364
Author(s):  
João Gonçalo Lourenço ◽  
Daniel Ettlin ◽  
Inês Carrero Cardoso ◽  
Jesus M. Rodilla
Keyword(s):  
Limit Of Detection ◽  
Gravimetric Method ◽  
Reference Value ◽  
Microwave Assisted Extraction ◽  
Closed Vessel ◽  
Limit Of Quantification ◽  
Microwave Assisted ◽  
Assisted Extraction ◽  
Total Fat

A simple and rapid method for the quantitation of total fat in olive samples is designed, evaluated, and presented. This method is based on an innovative closed-vessel microwave-assisted extraction (MAE) technique. A method was designed for olives, and some figures of merits were evaluated: limit of detection (LOD), limit of quantification (LOQ) and expanded uncertainty (U). The data obtained in these experiences show that the workflow of the MAE method in a closed container is statistically equivalent to the other two methods, showing in this case better performance indicators (LOD = 0.02%, LOQ = 0.06%, and U = 15%). In addition, it is also demonstrated that the complete MAE method workflow allows the determination of total fat in a maximum of 12 analyses simultaneously for about 100 min in each run, which is the capacity of the rotor. This is a much better productivity when compared to the traditional Soxhlet-based method. Considering the sample workflow, the closed-vessel MAE method greatly simplifies sample handling, therefore minimizing sample loss during sample preparation and reducing analysis time. When MAE is compared to NIR-based methods, the advantage comes from there being no need for any type of calibration in the sample matrix. The MAE method itself can be used to determine the reference value for NIR calibration purposes. The results obtained for CRM using MAE were equivalent to the ones shown on the certificate.

Ermittlung der Staubemissionen an Holz-Bearbeitungsmaschinen/Determining the dust emission of woodworking machines for risk assessment

2020 ◽  
Vol 110 (01-02) ◽  
pp. 64-69
Author(s):  
Hans-Christian Möhring ◽  
Thomas Stehle ◽  
Matthias Schneider
Keyword(s):  
Collection Efficiency ◽  
Dust Emission ◽  
Gravimetric Method ◽  
Measuring Method ◽  
Dust Exposure ◽  
Wood Dust ◽  
Suction System ◽  
Process Step ◽  
Machine Manufacturer ◽  
Detailed Assessment

Im Beitrag werden zwei Verfahren zur Ermittlung der Staubemission an Werkzeugmaschinen vorgestellt. Es werden das „gravimetrische Verfahren“ und die „Ermittlung des Erfassungsgrades“ beschrieben und gegenübergestellt. Das gravimetrische Verfahren zur Ermittlung des luftgetragenen Holzstaubs ist Stand der Technik zur Beurteilung der Staubemission von Holzbearbeitungsmaschinen. Dieses aufwendige Messverfahren mit Staub-Probenentnahmegeräten erlaubt eine Aussage über den Emissionsgrad der untersuchten Maschine. Dagegen quantifiziert die Ermittlung des Erfassungsgrades einer Bearbeitungsmaschine die Effektivität des Absaugsystems bei der Erfassung von Spänen und Stäuben. Ein Vergleich von Gravimetrie und Erfassungsgrad soll eine detaillierte Aussage zu den emittierten Späne- und Staubmengen von Bearbeitungsmaschinen für die Holz- und Holzwerkstoffbearbeitung liefern. Beim Messverfahren Ermittlung des Erfassungsgrades wird davon ausgegangen, dass Späne- und Staubfraktionen ähnlich gut erfasst werden können. Die genaue Zusammensetzung der erfassten und nichterfassten Materialanteile sowie der Partikelgrößen sind derzeit noch Gegenstand der Untersuchungen. Unbenommen davon müssen im Betrieb die nichterfassten Anteile aufwendig vom Benutzer in einem nachgelagerten Prozessschritt aufgesaugt werden. Es wird ausdrücklich darauf hingewiesen, dass die Untersuchung des Emissions- oder Erfassungsgrades einer Maschine nur eine qualitative Aussage zur Staubbelastung in der Umgebung einer Maschine erlaubt. Die Einwirkung beziehungsweise Exposition von Mitarbeitern hängt von Umgebungsbedingungen wie zum Beispiel Raumgröße, Luftwechsel, Sauberkeit, Leistung der Absauganlage, Beeinflussung durch Nachbararbeitsplätze (Bystanderexposition) und nicht zuletzt vom Handling des Bedieners ab. Diese Faktoren werden im Allgemeinen nicht von der Maschine beziehungsweise dem Maschinenhersteller beeinflusst.   This paper presents two methods for determining the dust emission of machine tools. The gravimetric method and the determination of the degree of collection efficiency are described and compared. compared. The gravimetric method for establishing airborne wood dust is state of the art for assessing the dust emission of woodworking machines. This complicated measuring method with dust sampling devices makes it possible to assess the emissivity of the examined machine. In contrast, establishing the degree of collection efficiency for a machining centre quantifies how efficient the suction system collects chips and dust. By comparing gravimetric analyses and the degree of collection efficiency, it is possible to provide a detailed assessment about the amount of chips and dust emitted by machining centres in the machining of wood and wood-based products. The measuring method for establishing the degree of collection efficiency assumes that chip and dust fractions can be collected similarly well. The exact composition of the collected and uncollected material fractions as well as the particle sizes still have to be examined yet. Irrespective of that, the uncollected particles have to be removed during operation in a subsequent, complicated process step by the user. It has to be emphasized particularly that by analysing the emissivity or the degree of collection efficiency of a machine it is only possible to qualitatively assess the dust exposure in the surroundings of the machine. The influence or exposure of workers depends on environmental conditions, such as e.g. room size, air change, cleanness, the efficiency of the suction system, the influence by adjacent machines (bystander exposure) and last but not least the handling of the operator. In general, these factors are not influenced by the machine or rather the machine manufacturer.

scholarly journals Exposure Assessment To Inhalable And Respirable Dust In The Post-Earthquake Construction Sites In The City Of L’aquila 

2019 ◽  
Author(s):  
Riccardo Mastrantonio ◽  
Angela Civisca ◽  
Tamara Lippolis ◽  
Enrica Inglese ◽  
Eugenio Siciliano ◽  
...  
Keyword(s):  
Geometric Mean ◽  
Crystalline Silica ◽  
Dust Concentration ◽  
Respirable Dust ◽  
Construction Sites ◽  
Mean Values ◽  
Silica Dust ◽  
Work Tasks ◽  
Inhalable Dust ◽  
The City

Abstract Following an earthquake occurred in the middle Italy in 2009, the involved territory hosted in ten years thousands of construction sites. The aim of this study is to assess the chemical exposure of the construction workers involved in the reconstruction of the city. To assess the exposure we collected 91 air samples to quantify the occupational exposure to airborne dusts and free crystalline silica dusts. Six construction companies joined the study and hosted the air sampling activities. We identified 4 work tasks: bricklayer and similar; scaffolder and carpenter; manual demolition; other tasks. Personal air sampling was performed by using the SKC AirCheck XR5000 sample pumps. Respirable dust and respirable crystalline silica dusts were collected by using a GS-3 Cyclones and 25 mm PVC filters; inhalable dust was collected by using a I.O.M. sampler and 25 mm PVC filters. The analyses were carried out by using gravimetric determination. Sampling time varied from 4 to 8 hours. The geometric mean values of inhalable dust concentration for the work tasks was: 3,65 mg/m 3 for scaffolder and carpenter; 18,16 mg/m 3 for manual demolition workers; 8,76 mg/m 3 for bricklayer and similar; 6,33 mg/m 3 for other work tasks. The geometric mean values of respirable dust concentration for the work tasks was: 0,67 mg/m 3 for scaffolder and carpenter; 0,92 mg/m 3 for manual demolition workers; 0,72 mg/m 3 for bricklayer and similar; 0,45 mg/m 3 for other work tasks. About the Crystalline Free Silica dust exposure, the average concentration in mg/m 3 was: 0,0038 for manual demolition workers, 0,0057 for scaffolder and carpenter, 0,004 for bricklayer and similar, 0,0035 for other tasks. The comparison of the results shows that manual demolition workers are exposed to considerably high levels of inhalable dusts, exceeding the ACGIH TLV-TWA limit of 10 mg/m 3 . About the respirable dust concentration, none of the work tasks dust concentration exceeded the ACGIH TLV-TWA limit of 3 mg/m 3 . Measurements of crystalline silica dust have shown levels below the threshold limit value of 0,025 mg/m 3 . This is in line with the average concentrations of respirable dust.

scholarly journals Side-by-Side Determination of Workers’ Exposure to Wood Dust with IOM And Openfaced Samplers

2013 ◽  
Vol 64 (3) ◽  
pp. 379-384 ◽  
Author(s):  
Anka Ozana Čavlović ◽  
Ružica Beljo Lučić ◽  
Matija Jug ◽  
Kristijan Radmanović ◽  
Ivan Bešlić
Keyword(s):  
Conversion Factor ◽  
Working Hours ◽  
Working Environment ◽  
Wood Dust ◽  
Exposure Data ◽  
Dust Mass ◽  
Inhalable Dust ◽  
Standards And Regulations ◽  
Mass Concentrations

Abstract Woodworkers’ exposure to airborne particles is measured with different sampling techniques throughout the world. Due to a great number of exposure data obtained with different samplers, European countries have aimed over the last ten years to find a conversion factor for mass concentrations that would render these measurements comparable. Following the accepted EU standards and regulations, we replaced a 25 mm open-faced (OF) filter holder with an IOM head to determine woodworkers’ exposure to inhalable dust and establish an IOM/OF sampler ratio that might serve as a reliable factor for converting the existing OF data to IOM dust mass concentration in the industrial environment. For this side-by-side sampling we used personal 25 mm OF (N=29) and IOM (N=29) sampling heads over eight working hours. The obtained IOM/OF ratios ranged between 0.7 and 2.3. However, mass concentrations obtained by IOM and OF samplers did not significantly differ. Our findings suggest that there is no need for conversion of the existing OF data for workers exposed to wood dust, provided that dust mass concentrations in the working environment range between 1 mg m-3 and 7 mg m-3. Future side-by-side measurements should also involve environments with low wood dust mass concentrations.

scholarly journals Ultrathin PANI-Decorated, Highly Purified and Well Dispersed Array Cncs for Highly Sensitive HCHO Sensors

Chemosensors ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 276
Author(s):  
Qingmin Hu ◽  
Zhiheng Ma ◽  
Jie Yang ◽  
Tiange Gao ◽  
Yue Wu ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Gravimetric Method ◽  
Chemical Vapor ◽  
Atomic Layer ◽  
Layer Deposition ◽  
Highly Sensitive ◽  
In Situ Methods ◽  
Good Repeatability ◽  
Novel Method

The flocculation of small surficial groups on pristine CNCs (carbon nanocoils) bundles limit their application. In this study, we designed and fabricated novel array CNCs with a surficial decoration of polyaniline (PANI) using in situ methods. Atomic layer deposition (ALD) and chemical vapor deposition (CVD) methods were employed to fabricate the highly pure array CNCs. The array CNCs decorated with ultra-thin PANI were confirmed by different characterizations. Furthermore, this material displayed a good performance in its detection of formaldehyde. The detection results showed that the CNCs coated with PANI had a low limit of detection of HCHO, as low as 500 ppb, and the sensor also showed good selectivity for other interfering gases, as well as good repeatability over many tests. Furthermore, after increasing the PANI loading on the surface of the CNCs, their detection performance exhibited a typical volcanic curve, and the value of the enthalpy was extracted by using the temperature-varying micro-gravimetric method during the process of detection of the formaldehyde molecules on the CNCs. The use of array CNCs with surficial decoration offers a novel method for the application of CNCs and could be extended to other applications, such as catalysts and energy conversion.

scholarly journals Comparison of Optical and Gravimetric Methods for Detection of Chymotrypsin

Proceedings ◽  
2020 ◽  
Vol 60 (1) ◽  
pp. 42
Author(s):  
Ivan Piovarci ◽  
Tibor Hianik ◽  
Ilia N. Ivanov
Keyword(s):  
Sample Preparation ◽  
Limit Of Detection ◽  
Optical Detection ◽  
Gravimetric Method ◽  
Milk Proteins ◽  
Industrial Processes

Proteases play an important role in various biological as well as dairy industrial processes. In this work, we focused on chymotrypsin, which is an important protease in human digestion. Chymotrypsin also cleaves milk proteins, which makes it useful in the study of activity of milk proteases. In this work, we focused on detection of chymotrypsin using optical and gravimetric techniques, their peculiarities, and the limit of detection (LOD) (0.15 ± 0.005 nM and 0.64 ± 0.31 nM for optical and gravimetric methods, respectively). While the optical detection is easier to implement, the gravimetric method is more robust for sample preparation. Both methods could represent a novel assay for detection of chymotrypsin and other milk proteases.

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