NF EN Research Articles

Démarche d’accréditation de l’analyse des légionelles dans les eaux chaudes sanitaires des bâtiments de la Marine nationale

All the public-access establishments must look for the presence and enumerate legionella in hot sanitary water. French Navy ships do not escape from this obligation. The laboratories carrying out these analyses must have the accreditation given by the COFRAC (French accreditation committee), according to the norm NF EN ISO 17025. This article aims to retrace the Brest French Navy Laboratory (LASEM de Brest) experience to obtain this accreditation. The following points have been particularly developed: the selection and control of consumables, the participation to the inter-laboratories tests and the evaluation of method performance.

Water absorption in recycled sand: New experimental methods to estimate the water saturation degree and kinetic filling during mortar mixing

Use of recycled concrete aggregates (RCA) as construction and building materials has not yet spread out. One of the reasons lies in porosity: a given RCA is more porous than its natural aggregate because of the presence of the attached old cement paste. This higher porosity causes inadequate mixing due to increase in both RCA water absorption and water exchange between RCA and new cement paste. It is thus necessary to quantify the weight fraction of in-pore water, which is usually done through the so-called water absorption coefficient (WAC), and to decrease this potential water exchange by pre-saturating the RCA. This paper aims to investigate mortar mixes made of RCA that is 1–4 mm in diameter called recycled sand (RS). It puts forward a new vacuum-based method combined with an evaporation method to measure the WAC, which permits saturating the RS fully and confirming that the standard method (NF EN 1097-6) largely underestimates the WAC (as already pointed out by other works). The evaporation method is also used to measure the water content of the pre-saturated RS, in order to evaluate the proportion of the pores that remain accessible to water even after pre-saturation, which was not done in other works. This paper then puts forward a new experimental approach to follow the absorption kinetics of the RS by immersing them into a limestone filler, which allows better reproduction of mixing mortar since aggregates are added into cement paste and not into water. Last, it is shown that adequately pre-saturating the RS can improve the mortar consistency.

Development of flame retardant cotton fabric based on ionic liquids via sol-gel technique.

In this study, flame retardant cotton fabrics were developed by the sol-gel method, in order to enhance their flame retardant proprieties. For this aim, seven sols were prepared using tetraethylorthosilicate (TEOS) and different ionic liquids (ILs) consist on pyridinium and Methylimidazolium cations with different anions such as: PF6−, CH3COO−, and Br−. Those sols were applied separately to the cotton fabrics by a pad-dry-cure process. The flame retardant properties of functionalized cotton fabrics before and after washing were determined by the vertical flame tests according to ISO6940:2004(F) standard. The effects of anions have been thoroughly investigated, aiming at the optimization of the targeted properties. Thermogravimetric and mechanical according to NF EN ISO 13934-1:2013standard, analyses have been also investigated. The results showed that flame retardancy, thermal stability and mechanical properties of treated fabrics were enhanced by using ionic liquids.

Evaluation of surgical glove integrity and factors associated with glove defect

Surgical glove perforation may expose both patients and staff members to severe complications. This study aimed to determine surgical glove perforation rate and the factors associated with glove defect. This descriptive cross-sectional study was conducted between January and March 2017 at a Tunisian university hospital center in 3 different surgical departments: urology, maxillofacial, and general and digestive. The gloves were collected and tested to detect perforations using the water-leak test as described in European Norm NF EN 455-1. For percentage comparisons, the χ2 test was used with a significance threshold of 5%. A total of 284 gloves were collected. Of these, 47 were found to be perforated, a rate of 16.5%. All perforations were unnoticed by the surgical team members. The majority of perforated gloves (61.7%) were collected after urology procedures (P = .00005), 77% of perforated gloves were detected when the duration of the procedure exceeded 90 minutes (P = .001), and 96% were from brand A, which were the thicker gloves (P = .015). This study highlighted an important problem neglected by surgical teams. The findings reaffirm the importance of double-gloving and changing gloves in surgeries of more than 90 minutes' duration.

Study of the pozzolanic activity of a dredged sediment from Dunkirk harbour

Admixtures or supplementary cementitious materials are generally characterised by their ability to react in specified conditions. This can be assumed through the pozzolanicity. In this study, the pozzolanic activity of a certain category of materials was investigated. For this purpose, the Frattini test conforming to NF EN 196-5 French standard, the accelerated Chapelle test, the measurement of the electrical conductivity and the calculation of mechanical activity coefficient were performed. The raw sediment from Dunkirk harbour presented a relatively low pozzolanic activity regardless of the test considered. However, the study of direct or flash calcined materials evidenced that sediment acquired at the end of these processes an improvement of pozzolanic activity. The comparative study conducted on several common admixtures also inferred that the Chapelle and mechanical activity index methods are quite appropriate and reliable. Nevertheless, in the conductivity test, a correction must be applied due to the presence of dissolved salts. A mechanical activity coefficient of χA=0.88 and χA=0.73 was determined for STFC (flash) and STDC (direct lab kiln) respectively.As a result, sediment, following an optimized treatment can be used as active mineral admixture in cementitious matrixes.

Innovative non-thermal plasma disinfection process inside sealed bags: Assessment of bactericidal and sporicidal effectiveness in regard to current sterilization norms.

In this work, we developed a device capable to generate a non-thermal plasma discharge inside a sealed bag. The aim of this study was to assess the effectiveness of the oxygen, nitrogen and argon plasma sterilization on Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis spores according to the NF EN 556 Norm. Moreover the bag integrity which is a critical key to maintain the sterile state of items after the end of the process was verified by Fourier Transform Infrared (FTIR) and X-ray Photoelectron Spectrometry (XPS) analyses. After plasma treatments, the bacterial counting showed a 6 log reduction of P. aeruginosa and S. aureus in 45 min and 120 min respectively whatever the gas used and a 4 log reduction of B. subtilis spores in 120 min with only oxygen plasma. These results were confirmed by Scanning Electron Microscopy (SEM) observations showing altered bacteria or spores and numerous debris. Taking into account the studied microorganisms, the oxygen plasma treatment showed the highest efficiency. FTIR and XPS analyses showed that this treatment induced no significant modification of the bags. To conclude this non-thermal plasma sterilization technique could be an opportunity to sterilize heat and chemical-sensitive medical devices and to preserve their sterile state after the end of the process.

Simultaneous determination of tryptophan and 8 metabolites in human plasma by liquid chromatography/tandem mass spectrometry.

Tryptophan (Trp) is an essential amino-acid and the precursor of many biologically active substances such as kynurenine (KYN) and serotonin (5HT). Its metabolism is involved in different physiopathological states, such as cardiovascular diseases, cancer, immunomodulation or depression. Hence, the quantification of Trp catabolites, from both KYN and 5HT pathways, might be usefulfor the discovery of novel diagnostic and follow-up biomarkers. We have developed a simple method for quantification of Trp and 8 of its metabolites,involved in both KYN and 5HT pathways, using liquid chromatography coupled to tandem mass spectrometry. We also validated the methodin human plasma samples, according to NF EN ISO 15189 criteria. Our method shows acceptable intra- and inter-day coefficients of variation (CV) (<12% and <16% respectively). The linearity entirelycovers the human plasma range. Stabilities of whole blood and of residues weredetermined, as well as the use of 2 different types of collectiontube, enabling us to adapt our process. Matrix effects and reference values showed good agreement compared to the literature. We propose here a method allowing the simultaneous quantification of a panel of Trp catabolites, never used before to our knowledge. This method, witha quickchromatographic runtime (15min) and simple sample preparation, has beenvalidated according to NF EN ISO 15189 criteria. The method enables the detailed analysis of these metabolic pathways, which are thought to be involved in a number of pathological conditions.

New experimental approach of the reuse of dredged sediments in a cement matrix by physical and heat treatment

In this study, a sediment was used as a secondary raw material in cement substitution with prior treatment. The treatment adopted is a physical treatment involving grinding and separation to obtain different fractions, using a dry method (1mm, 250µm, 120µm) and washing method (250µm and 120µm). They were subsequently heat treated at temperatures of 650°C, 750°C and 850°C for 1h and 3h, in order to enable chemical activation by decarbonation or by pozzolanic activation of the material.Different characterization tests were performed. The determination of main physical and chemical characteristics was obtained through multiple techniques: particle size distribution, specific density, the BET surface area, the initial setting time and hydration heat calorimetry Langavant. The chemical tests include: TGA analysis, X-ray diffractometry (XRD) and X-ray fluorescence (XRF) which were used to quantify the fractions, phases and chemical elements present. Compression tests were performed conforming NF EN 196-1 French standard, over terms of 7days – 14days – 28days and 60days on all formulated mortars: reference mortar based on 100% CEM I 52.5N binder and cement substituted mortars with 8% and 15% by treated sediment. This clearly evidenced contribution due to chemical activity which was confirmed by calorimetry monitoring and strength investigation.

Characterization of Tannin-Based Resins from the Barks of &amp;lt;i&amp;gt;Ficus platyphylla&amp;lt;/i&amp;gt; and of &amp;lt;i&amp;gt;Vitellaria paradoxa&amp;lt;/i&amp;gt;: Composites’ Performances and Applications

This work investigates the physico-chemical and mechanical properties of tannins extracted from wood for composite materials manufacturing. Sustainable knowledge (in terms of physico-chemical properties and behaviours) of the material is needed to further enhance its applications. The condensed tannins extracted from the Bark of Ficus platyphylla (BFP) and the Bark of Vitellaria paradoxa (BVP) were analyzed using Matrix Assisted Laser Desorption/Ionization Time-Of-Flight (MALDI-TOF), Mass Spectroscopy and Attenuated Total Reflectance Fourier Transform Mid-InfraRed (ATR-FT MIR) spectra in the ranges 1800 cm-1 and 600 cm-1, as well as using CP MAS 13C-NMR. It was found that, these two tannins are procyanidin/prodelphinidin and made up of catechin/epicatechin, gallocatechin/epigallocatechin units, fisetinidin, galloyl and carbohydrates residues. Furthermore, BFP and BVP tannin bonded particleboard densities lie in the range recommended by NF EN 326-1994 standard. The resins also yielded good internal bond strength results of the panels, above relevant international standard specifications minimum requirements for interior-grade panels. The Transmission Electron Microscopy with Energy Dispersive X-ray Spectroscopy Analysis (TEM/ EDXA) are showing the ultrastructure and reveal that most of the resin material appears to be in an amorphous phase mainly composed of carbon/oxygen with small amounts of K, Ca and Mg. These particles have a very irregular morphology.

Comparative natural durability of four Mediterranean softwoods against wood decay fungi

Atlas cedar (Cedrus atlantica Manetti), thuya (Tetraclinis articulata (Vahl) Masters), Aleppo pine (Pinus halepensis Mill.), maritime pine (Pinus pinaster var atlantica Ait) are among important Mediterranean coniferous species that provide softwood round timber. Atlas cedar and thuya are well known for their noble timber used in ebinestry and marquetry while those of the two pines are mainly used as wood service. The natural durability is an important property of wood regarding performance and service life. The present work is conducted to assess the natural durability of these woods against wood destroying fungi, in laboratory test, according to the methods described in the European standards, CEN/TS 15083-1 and NF EN 350-1. Mass losses of wood specimens, after 16 weeks of exposure to fungi attack, showed that C. atlantica and T. articulata woods are very durable to durable against wood-decay fungi attack. Such natural durability allows these woods to access the risk classes of biological attacks 4 and 5 (high risk) for end-use without preservative treatment, while P. halepensis and P. pinaster var atlantica woods, classified as less to none durable, must be treated before use at high risk classes circumstances.

Proposal of manufacturing and characterization test of binderless hemp shive composite

In recent years, there has been increasing interest in producing an alternative environmentally friendly composite instead of the non-biodegradable (plastic) or formaldehyde emission composites. With this goal, composites of 100% hemp waste were converted through the one-step thermoforming process to obtain ecological binderless particleboard. In this study, the effects of the particle sizes, the moisture content and the heating temperatures under fixed pressure and time were studied to investigate the physical, thermal and mechanical properties of these composites. We observed that the composites of fine particles always had the better properties, at an optimum temperature of 170 °C. Interestingly, this composite had a maximum flexural strength of 27 ∓ 11 MPa and a modulus of elasticity of 3122 ∓ 763 MPa. This resistance satisfied the requirements of (NF EN 312:P6) for particleboards. On the contrary, these composites were very sensitive to water; they completely collapsed within 5 min of direct water contact. This behavior is preferable from the point of view of the biodegradability. Actually, after the end of service life of this lignocellulosic composite, the fermentation process can be achieved to generate ligninolytic fungi and enzymes which are involved in the degradation of the complex and recalcitrant polymer lignin.

Characterization, firing behavior and ceramic application of clays from the Gabes region in South Tunisia

In this study, a part of paper has been conducted on geological survey of Gabes clays and their surroundings; so we can focus on the highest thicknesses of clay sediments, for subsequent investigation or exploration. The greatest part of work focuses on the mineralogical, chemical, physical, and geotechnical tests carried out on Creatceous clays collected from the Zimlet El Beida in Gabes area (South-eastern Tunisia). Firing behavior and ceramic application are also conducted for these clay materials. The mineralogy study shows illitic clays; however, other clay minerals, such as kaolinite, mixed-layer I/Sm and chlorite are also present. The mineralogical phases during the firing process were recorded at 300, 600, 800, 1000 and 1150°C for 3h with heating rate of 10°C/min. The main transformations were observed at 1000°C with the appearance of new crystalline phases, such as diopsite, cristobalite, mullite and spinel. The chemical analysis indicates that these clays are notably siliceous. The alkali content (K2O+Na2O) is high (~ 4.13%), thus explaining why these clays can be fired at relatively low temperatures. The amount of alumina and iron oxide, with an average of 16.42 and 7.07% respectively, is variable. The tests show that these clays have medium plasticity values (PI =14–20%). The firing shrinkage and the expansion are limited. A lower firing and drying temperature can be translated into significant energy savings. Technical tests show that the properties fall within the ceramic International Standards (ISO). Ceramic tiles made of these clays have appropriate characteristics without defects and can be classified in group BIII and BIIb according to the European Standard NF EN 159 (1991).

Development of a Multi-Sensitive Element Passive Dosemeter Based on OSL Technology.

In 2012 the IEC 62387-1:2007 (IEC.Radiation protection instrumentation-Passive integrating dosimetry systems for environmental and personal monitoring Part 1: General characteristics and performance requirements. IEC 62387-1:2007 (2007)) standard has been transposed by the CENELEC into a European version (EN 62387-1:2012 (Instrumentation pour la radioprotection-Systèmes dosimètriques intégrés passifs pour la surveillance de l'environnement et de l'individu-Partie 1 : Caractéristiques générales et exigences de fonctionnement. NF EN 62387-1:2012 (2012))). In order to meet with this standard, LANDAUER has developed, by Monte-Carlo method, a new dosemeter based on the Optically Stimulated Luminescence technology with Al2O3:C crystals and a new type of dose estimation algorithm. This dosemeter aims at measuring dose equivalent generated from exposure to X-rays, γ-rays and β-rays. According to the standard, it has undergone a comprehensive set of tests that have been performed by the LNE-LNHB, the French national metrology laboratory responsible for the fields of ionizing radiation (Bordy, J.-M. Evaluation of the algorithms used to derive the dose from the raw readings of the Inlight LDR holder case type GN of Landauer. LNHB technical note, LNHB 2013-46 (2013)). In the end, the dosemeter was declared compliant with the EN 62387-1:2012 standard.

Water-based flame retardant coating using nano-boehmite for expanded polystyrene (EPS) foam

Expanded polystyrene (EPS) foam has been successfully flame retarded by a water-based coating containing nanoparticles of boehmite and poly(vinyl alcohol) (PVOH) as char former. Boehmite enhances the charring of PVOH. The influence of suspension viscosity, coatings number, impregnation time and drying method was studied to monitor the amount of coating deposited and the coating thickness. The coating suspension is able to penetrate into the core of the foam. EPS without hexabromocyclododecane (HBCD) is upgraded from F to E rating according to the NF EN ISO 11925-2 standard when the penetration of coating suspension into the core is high enough, due to the formation of a char layer reinforced by nano-boehmites even if EPS does not shrink away from the flame.

Characterization of coffee residues pellets and their performance in a residential combustor

ABSTRACTSpent coffee grounds (SCG) and coffee husks (CH) were evaluated as biofuels, after densification, for energy production. CH represent a specific problem for the coffee industry due to a low calorific value, high ash content, and a very low bulk density. Hence, the energetic potential of SCG (95 wt%)/CH (5 wt%) blend and pure SCG (100%) were examined. The blend of SCG and CH was limited to 5 wt% of CH because of the low bulk density of CH. Therefore, physicochemical and energetic characterizations of the produced pellets were performed. Thermogravimetric analyses were performed under nitrogen and air atmospheres to evaluate the CH behavior in the blend. Characterization study shows that both produced pellets could reach the French Agropellets standard (AQI). Thermal degradation showed that the mean reactivity of the SCG/HC pellets was higher than pure SCG. Then, combustion experiments were performed in a domestic combustor, after modification of the boiler power in order to improve its energetic performances. The presence of CH led to a rise of CO, NOx, VOC’s, and particle emissions. Nevertheless, the performances of the biofuels are almost in agreement the NF EN 12809 standard.

Characterization and traditional ceramic application of clays from the Douiret region in South Tunisia

This study of the Aptian clays of Douiret (south-east of Tunisia) and their use in ceramic industry is original. At first, mineralogical, chemical, physical and thermal analyses of these clays are given. In terms of mineralogy, they can be considered as illitic clays (50–67%). However, other clay minerals, such as kaolinite, I/Sm mixed-layer, quartz, feldspar, dolomite and hematite, are present in small quantities. Next, this study reveals that the average amounts of silica and potassium are 53.9% and 3.3% respectively. The amount of alumina and iron oxide, with an average of 16.8% and 6.3% respectively, is variable. The plasticity test shows a high value (PI=39–56%). The mineralogical changes during the firing process were recorded via the X-ray diffraction of the raw clays and subsequent firing at 300, 700, 800, 900 and 1150°C for 3h with heating rate of 10°C/min. The main transformations were observed at 900°C with the appearance of new crystalline phases especially mullite, anortite and spinel. Technical tests show that the properties fall within the ceramic International Standards (ISO). Finally, ceramic tiles and bricks prepared from these clays have suitable characteristics without defects and can be classified in group BIII according to the European Standard NF EN 159 (1991).

Natural durability of Cedrus atlantica wood related to the bioactivity of its essential oil against wood decaying fungi

The Atlas cedar, Cedrus atlantica is a resinous species of Pinaceae originated from North Africa and well known for its noble timber. This work was conducted to assess the natural durability of its wood, to study the chemical composition of essential oil extracted from its sawdust wood and to test the bioactivity of this essential oil against four wood decaying fungi: Gloeophyllum trabeum, Oligoporus placenta, Coniophora puteana and Trametes versicolor. The assessment of natural durability of wood was conducted according to the methods described in the European standards, CEN/TS 15083-1 and NF EN 350-1. Mass losses of wood specimens, after 16 weeks of exposure to fungi attack, in laboratory test, showed that Cedrus atlantica wood is very durable to durable against wood decay fungi attack. The extraction of essential oil from sawdust by hydro-distillation yielded about 3,35% and the chemical analysis of this essential oil by GC-MS showed that E-γ-Atlantone (19,73%); E-α- Atlantone (16,86%), 5-Isocedranol (11,68%); 9-iso-Thujopsanone (4,45%); Cedranone (4,13%) and Z α- Atlantone (4,02%) were the main major identified components. The antifungal activity tested by the direct contact technique on agar medium showed a strong inhibition of wood decaying fungi, especially Gloeophyllum trabeum inhibited at 1/1000 v/v concentration.

Analysis of MGMT methylation with the therascreen(®) MGMT Pyro(®) Kit (Qiagen). A method verification

Promoter methylation of the MGMT gene, encoding the enzyme O6-methylguanine-ubiquitous methyltransferase, is a theranostic good prognosis marker of glioblastomas treated with alkylating chemotherapy (temozolomide, Temodal(®)). Among the methylation analysis techniques, pyrosequencing is a reproducible and sensitive quantitative method. As part of the accreditation of the hospital platform of molecular genetics of cancer, Besançon, our objective was to verify the performance of the pyrosequencing commercial kit therascreen(®) MGMT Pyro(®) (Qiagen) in terms of repeatability, reproducibility, limit of blank (LOB), limit of detection (LOD), linearity and contamination by the guide SH GTA 04 delivered by the Cofrac. The repeatability tests show an average methylation of 3.22% [standard deviation (SD) = 0.41, coefficient of variation (CV) = 12.75%] for the unmethylated control and 70.16% (SD = 2.20, CV = 3.14%) for the methylated control. Reproducibility demontrates an average methylation of 1.39% (SD = 0.25, CV = 18.25%) for the unmethylated control and of 94.03% (SD = 2.56, CV = 2.73%) for the methylated control. The percentages of LOB and LOD are respectively 3.43% and 6.22% methylation. The regression coefficient of 0,983 confirms the linearity of the assay from 0% to 100% methylation. No contamination has been observed. Over 40% of glioblastomas studied in 2013 in our laboratory have shown a methylated MGMT gene. Our results confirms that the theraScreen(®) MGMT Pyro(®) kit (Qiagen) is performant in compliance with the quality requirements of the NF EN ISO 15189 for the routine analysis of methylation status of MGMT in glioblastomas.

Mechanical Strength of Hydraulic Binder Made by Blending Type I Portland Cement and Pozzolan

The mechanical strength of hydraulic binder made by blending type I Portland cement (PC) and pozzolan has been examined at the age of 3, 7, 14, 28 and 90 days.The mechanical strength test was realized by using mortar specimens measuring 40x40x160 mm according to NF EN 196-1. The mix proportion of mortarwas 0.5 water :1.0 hydraulic binder : 3.0 sand, by weight.The hydraulic binder was a mixture of 80% PC and 20% pozzolan. Five types of pozzolan were used in this study: two natural pozzolan and three artificial pozzolan. As a control, it was made a mortar havingthe same proportion except that the hydraulic binder was 100% PC. The test result showsthat all of pozzolan present a good pozzolanic reactivity. At 3 days,the strength of the mortar with blended binder (MBB) is lower than the strength of the control mortar (CTM). At that time, the flexural tensile strength and the compressive strength of the MBB rangerespectively from 5.23 to 6.81 MPa and from 13.61 to 18.37 MPa, whereas the CTM strength has reached 7.30 MPa and 27.92 MPa. The MBB strength increasesand it canachieve or even exceed the CTM strengthwith increasing age of hydration. In fact, at 90 days, the flexural tensile strength and the compressive strength ofMBB can reach about 10.08 to 11.06 MPa and 49.69 to 54.17 MPa respectively. In this period of hydration, the flexural tensile strength and the compressive strength of CTM are only 10.13 MPa and 49.00 MPa. The different development of the mechanical strength of MBB could be stronglyrelated to the chemical content of the pozzolan used, especially, reactive silica and reactive alumina.

Bactericidal activity of 3 cutaneous/mucosal antiseptic solutions in the presence of interfering substances: Improvement of the NF EN 13727 European Standard?

ObjectiveThere is no standard protocol for the evaluation of antiseptics used for skin and mucous membranes in the presence of interfering substances. Our objective was to suggest trial conditions adapted from the NF EN 13727 standard, for the evaluation of antiseptics used in gynecology and dermatology. MethodsThree antiseptic solutions were tested in vitro: a chlorhexidine-benzalkonium (CB) combination, a hexamidine-chlorhexidine-chlorocresol (HCC) combination, and povidone iodine (P). The adaptation of trial conditions to the standard involved choosing dilutions, solvent, and interfering substances. The activity of solutions was assessed on the recommended strains at concentrations of 97% (pure solution), 50%, and 10% (diluted solution), and 1%. A logarithmic reduction ≥ 5 was expected after 60seconds of contact, to meet requirements of bactericidal activity. ResultsHCC did not present any bactericidal activity except on P. aeruginosa at a concentration of 97%. P was not bactericidal on E. hirae at any concentration and on S. aureus at 97%. CB had the most homogeneous bactericidal activity with a reduction>5 log on the 4 bacterial strains at concentrations of 97%, 50% and 10%. ConclusionAdapting the NF EN 13727 standard allowed assessing the 3 tested solutions: only CB was bactericidal in dirty conditions. This study proved the possibility of validating antiseptic choice in vitro, in current practice conditions, for adjunctive treatment of skin and mucous membranes disorders, primarily of bacterial origin or with a potential of superinfection.