Search

Phenols are widely used in industry as part of the ingredients in disinfectant, antiseptic and household cleaning products. An increased usage of phenol has caused an increase in its content in water sources and at the same time brings negative effect to the environment. This paper reported an approach consisting of dispersive liquid-liquid microextraction (DLLME) combined with UV-Vis spectrophotometric detection at 280 nm in order to extract phenol in water samples. Some difficulties were reported in the formation of a double layer for separation between the dispersive and extraction solvent which is important to ensure the successful DLLME application and the high percent recovery of the extracted phenol. Therefore, our research interest focused on the effect of dispersive and extraction solvents by using different solvent characteristics for phenol extraction from real water. The optimum conditions, i.e., extraction solvent (1-dodecanol) volume of 2 mL and dispersive solvent (dimethyl sulfoxide) volume of 2.5 mL, were determined using response surface methodology. DLLME-UV-Vis is a suitable method for phenol extraction because it is simple, fast, low cost and produces high percentage recovery of phenol., Author(s): Mohammad Fauzan bin Mhd Himmi [sup.1], Beh Shiuan Yih [sup.1], Farhanini Yusoff [sup.2], Noorashikin Md Saleh [sup.1] Author Affiliations: (1) grid.412113.4, 0000 0004 1937 1557, Department of Chemical and [...]

The analysis and detection of caffeine (Caf) is very useful due to its widespread usage in several daily consumed beverages, food products, and pharmacological preparations with various physiological effects. The preparation of a newly electrodeposited Ag nanoparticles - cellulose acetate phthalate (CAP) - chitosan (Chit) modified carbon paste (ACCMCP) sensor for sensitive determination of Caf in 0.01 mol [L.sup.-1] [H.sub.3]P[O.sub.4] solution (pH 1.0-5.0) both in aqueous and micellar media (0.5 mmol [L.sup.-1] SDS) was achieved. The interaction of Caf was monitored using electrochemical techniques such as cyclic voltammetry, differential pulse voltammetry, electrochemical impedance spectroscopy, and chronoamperometry, and surface characterization was carried out using X-ray diffraction, scanning electron microscope, and energy dispersive X-ray techniques. The linear detection range of Caf was between 4 and 500 [micro]mol [L.sup.-1] ([r.sup.2] = 0.955) and the limit of detection obtained from the calibration plot was 0.252 [micro]mol [L.sup.-1]. The sensor was applicable for detecting Caf in numerous real samples with recoveries from 98.03% to 101.60% without interference of any accompanying species, which ensures high method selectivity. Key words: caffeine, Ag nanoparticles, EIS, cellulose acetate phthalate, Panadol. La detection de la cafeine (Caf) est devenue un enjeu incontournable en raison de son utilisation largement repandue dans plusieurs boissons, produits alimentaires et preparations pharmacologiques consommes quotidiennement et qui procurent divers effets physiologiques. Nous avons prepare un nouveau capteur a pate de carbone modifiee par des nanoparticules d'Ag electrodepose, de l'acetophtalate de cellulose (CAP) et du chitosane (Chit) pour le dosage sensible de la Caf dans une solution a 0,01 mol [L.sup.-1] de [H.sub.3]P[O.sub.4] dans l'intervalle de pH de 1,0 a 5,0 en milieu aqueux de meme qu'en milieu micellaire (0,5 mmol [L.sup.-1] SDS). Nous avons utilise de nombreuses techniques electrochimiques, telles que la voltamperometrie cyclique, la voltamperometrie differentielle pulsee, la spectroscopie d'impedance electrochimique et la chronoamperometrie, pour observer l'interaction de Caf avec le capteur, et nous avons caracterise la surface de celui-ci a l'aide des techniques de diffraction des rayons X, de microscopie electronique a balayage et de spectroscopie de rayons X a dispersion d'energie. Le domaine lineaire de detection de la Caf allait de 4 a 500 [micro]mol [L.sup.-1] (r (2) = 0,955), et la limite de detection obtenue a partir de la courbe de calibration etait de 0,252 [micro]mol [L.sup.-1]. Nous avons applique le capteur a la detection de la Caf dans de nombreux echantillons reels avec des taux de recuperation variant de 98,03 a 101,60 %, sans interference de toute espece en presence, ce qui demontre la selectivite elevee de cette methode. [Traduit par la Redaction] Mots-cles: caffeine, nanoparticules d'Ag, SIE, acetophtalate de cellulose, Panadol., Introduction Caffiene (Caf) is a highly important alkaloid derivative found in several beverages like coffee, tea, and energy drinks and is also found in many drugs. (1) It has clinical [...]

The increased pressure on timber supply due to a reduced forest land base urges the development of new approaches to fully capture the value of forest products. This paper investigates the effects of knowing the position of knots on lumber volume, value, and grade recoveries in curve sawing of 31 white spruce (Picea glauca (Moench) Voss) and 22 jack pine (Pinus banksiana Lamb.) trees. Internal knot position was evidenced by X-ray computed tomography (CT) imaging, followed by the application of a knot-detection algorithm allowing log reconstruction for use as input in the Optitek sawing simulation software. Comparisons of the three levels of sawing optimization (sweep up, shape optimized, and knot optimized) revealed that considering internal knots before log sawing (e.g., knot optimized) generated 23% more lumber value for jack pine and 15% more for white spruce compared with the traditional sweep-up sawing strategy. In terms of lumber quality, the knot-optimized strategy produced 38% more pieces of grade No. 2 and better in jack pine and 15% more such pieces in white spruce compared with the sweep-up strategy. These results indicate a great potential to increase manufacturing efficiency and profitability by implementing the CT scanning technology, which should aid in developing a strong bioeconomy based on an optimized use of wood. Key words: X-ray computed tomography (CT scan), sawing optimization, knots, sweep, lumber recovery. La pression accrue sur l'approvisionnement en bois causee par la reduction du territoire forestier exige qu'on developpe de nouvelles approches pour tirer la pleine valeur des produits forestiers. Cet article etudie dans quelle mesure le fait de connaitre la position des nreuds peut ameliorer le volume, la valeur et la classe du bois d'reuvre recupere avec le sciage courbe de 31 tiges d'epinette blanche (Picea glauca (Moench) Voss) et de 22 tiges de pin gris (Pinus banksiana Lamb.). La position des nreuds dans le bois a ete detectee par tomodensitometrie dont les donnees ont ete traitees avec un algorithme de detection des nreuds permettant la reconstitution des billes qui sert par la suite d'intrant dans le logiciel d'optimisation du sciage Optitek. Les comparaisons de trois degres d'optimisation du sciage (courbure maximale de la bille dans l'axe vertical, optimisation basee sur la forme, optimisation basee sur la dimension et l'emplacement des nreuds) ont revele que le fait de tenir compte des nreuds avant de scier les billes (p. ex. optimisation basee sur la dimension et l'emplacement des nreuds) a permis de produire du bois d'reuvre qui avait plus de valeur, soit 23 % dans le cas du pin gris et 15 % dans le cas de l'epinette blanche comparativement a la strategie traditionnelle de sciage (courbure maximale de la bille dans l'axe vertical). En termes de qualite du bois d'reuvre, la strategie d'optimisation faisant intervenir les nreuds a produit plus de pieces No 2 et meilleur, soit 38 % dans le cas du pin gris et 15 % dans le cas de l'epinette blanche comparativement a la strategie traditionnelle. Ces resultats indiquent que l'implantation de l'imagerie tomodensitometrique a un fort potentiel pour augmenter l'efficacite et la profitabilite de la transformation, ce qui devrait contribuer a developper une solide bioeconomie basee sur une utilisation optimale du bois. [Traduit par la Redaction] Mots-cles: tomodensitometrie, optimisation du sciage, nreuds, courbure, recuperation du bois d'reuvre., Introduction Canada is facing a reduced forest land base due to increasing natural and climate-related disturbances, including wildfire and pests, and societal decisions leading to forest protection or non-timber uses [...]

HIGHLIGHTS * Small practices can do some encrypting on their own by using tools for certain versions of Windows that enable encryption within an EHR and backup software. * A [...]