354 research outputs found
Recent Developments in Radical Photoinitiator Chemistry
Radiation curing is an established technology used in many industrial manufacturing processes. New applications and technical specifications stimulate the continuous development of tailor-made photoinitiators which can efficiently meet specific requirements. A new class of radical photoinitiators,
bisacylphosphine oxides (BAPO), give four initiating radicals per photoinitiator molecule and undergo photo-bleaching of the low-energy absorption band. These features make the compounds highly efficient for radiation curing of highly opaque white pigmented systems, thick coatings, or fiber-reinforced
formulations
The Dimensionality of Factors Underlying Satisfaction With Continuing Care Retirement Communities.
The purpose was to develop and test a model to predict satisfaction with consumer selection of continuing care retirement communities (CCRCs). The family resource management conceptual framework of Deacon and Firebaugh (1988) provided the theoretical base for development of the proposed model. Another area of study, consumer behavior, was drawn upon to find pertinent indicators for the decision-making component of the model. Constructs of the Engel, Blackwell and Miniard (1990) consumer behavior model were incorporated to represent the managerial aspect of the family resource management model. The model was tested by applying it to the CCRC selection process of consumers. A random sample of 75 CCRCs, stratified by regions of the country, was drawn. Administrators of 22 of the CCRCs drawn agreed to participate by providing names and addresses of residents who had joined the CCRC within one year of the start of the study. A questionnaire designed by the researcher and based on Dillman\u27s (1978) total design method was mailed to 650 subjects. A follow-up mailing sequence was implemented, and 374 usable questionnaires were returned, for a response rate of 58%. Factor analyses were performed, and factor scores were used to represent groups of variables in the model. Four hypotheses were tested using multivariate multiple regression analysis, and univariate tests were performed to assist in interpretation of the multivariate tests. The hypotheses included: (a) the managerial process of consumers selecting a CCRC will be predicted by resources and demands; (b) knowing the resources and demands of consumers selecting a CCRC will help predict satisfaction with the CCRC and its characteristics; and (c) knowing the managerial process used by CCRC consumers will help predict satisfaction. The primary hypothesis was that given input, the addition of the throughput component (the managerial process of CCRC consumers) to the proposed model would increase the ability to predict satisfaction. Each of the four hypotheses was supported. A major finding was the positive relationship between use of search strategies and satisfaction, indicating that consumers using an effective search process were more satisfied with the CCRC and its characteristics. Implications for use of the findings and recommendations for future research are offered
Détection de ruptures en ligne par estimateur SVM de support de densité
Nous proposons une méthode d'apprentissage automatique visant à détecter des ruptures dans une suite de vecteurs. Notre algorithme appartient à la famille des méthodes dites à noyau et repose sur la transposition du problème étudié dans un espace hilbertien muni d'un noyau reproduisant. Un indice de stationarité est construit dans cet espace, où l'on compare deux cercles (qui résultent de l'estimation de deux supports de densité) à l'aide d'un critère de type Fisher. Une rupture correspond à une distance importante entre les centres des deux cercles (relativement à leur rayon). Nous montrons que cet indice peut en fait être calculé dans l'espace de départ; des simulations illustrent l'efficacité de la méthode sur des données réelles
PACE Solver Description: DreyFVS
We describe DreyFVS, a heuristic for Directed Feedback Vertex Set submitted to the 2022 edition of Parameterized Algorithms and Computational Experiments Challenge. The Directed Feedback Vertex Set problem asks to remove a minimal number of vertices from a digraph such that the resulting digraph is acyclic. Our algorithm first performs a guess on a reduced instance by leveraging the Sinkhorn-Knopp algorithm, to then improve this solution by pipelining two local search methods
Study of the release of limonene present in chitosan films enriched with bergamot oil in food simulants
[EN] Chitosan films containing different concentrations of bergamot oil (BO) were obtained and the migration of limonene, the major oil component, to five liquid food simulants (aqueous solutions with 0%, 10%, 50% and 95% of ethanol and isooctane) was studied at 20 degrees C. The losses of BO and limonene during the film drying were also quantified. The release kinetics of limonene from chitosan matrix was described using an empirical model which relates the reduced concentration loss of limonene and the square root of time. The results show that kinetic constants for all films increased exponentially when the ethanol concentration increased in the aqueous system and were slightly greater when the film thickness was lower. Composite films remain intact in isooctane CH-BO and no release of limonene was observed. Hydration of the film to promote molecular mobility was essential to ensure the compound release. (C) 2011 Elsevier Ltd. All rights reserved.The author L. Sanchez-Gonzalez thanks the Ministerio de Educacion y Ciencia (Spain) for a FPU Grant (AP2006-026).Sánchez González, L.; Cháfer Nácher, MT.; González MartĂnez, MC.; Chiralt, A.; Desobry, S. (2011). Study of the release of limonene present in chitosan films enriched with bergamot oil in food simulants. Journal of Food Engineering. 105(1):138-143. https://doi.org/10.1016/j.jfoodeng.2011.02.016S138143105
Extraction, chemical composition and nutrional characterization of vegetable oils: Case of Amaranthus hybridus (var 1 and 2) of Congo Brazzaville
Amaranthus hybridus is a vegetable which is eaten in Congo Brazzaville and in other countries. Two varieties of A. hybridus seeds (var 1 and 2) were selected for this study. Average oil content varies between 11 and 14%. A. hybridus seeds are also rich in proteins (17%) and minerals. Red oils obtained have a high saponification value (130-190) and the iodine value is between 100 and 113. The quantity of unsaponifiable matter (5 - 7%) in these oils is important. The fatty acids composition gives the following average profile: 18: 2n-6 > 18: 1 n-9 > 16: 0 > 22: 6n-3 > 18: 0. A. hybridus seeds oils also have long chain poly unsaturated fatty acids such as DHA (5.63-21.46%) and the results indicated that the n-6/n-3ratios were 1.48 to 5.63. The triacylglycerols analysis shows that oils extracted by Bligh and Dyer method contains 6 major TAGs in A. hybridus var1: LLnLn › OLL › POL. › OLL › PLL › LLL and Amaranthus hybridus var2: LLnLn › OLL › PLL › POL. › OLL › LLL. The A. hybridus seeds can be used ascattle food and baby complement food. These oils have nutritive and dietetic potentialitie
Extraction and nutritional properties of Solanum nigrum L seed oil
With the aim of diversifying the lipids sources eaten by the African populations and those of Congo Brazzaville in particular, a physicochemical study of Solanum nigrum L seeds was carried out and three chemical methods (Soxhlet, Bligh and Dyer, and Folch) were used to extract the oil. The dry matter content of the seeds is 94.22%. Average lipids content varies between 34.5 and 37.5% dry matter, proteins content is 17% dry matter and crude ash content averages 7.18% dry matter and the principal mineral element is Mg (180 mg/100g). The acid value of the oil is about 2.5, saponification value varies between 157.3 and 190.1, peroxide value is low at 5.13 and iodine is 102.33.The fatty acid compositions of S. nigrum seeds oil shows that it has 67.9% of linoleic acid, indicating its high unsaturation. Apart from linoleic acid, other prominent fatty acids were palmitic, stearic and oleic acids. The following average profile is: 18: 2n-6 > 18: 1 n-9 > 16: 0 > 18: 0. The oil is liquid at room temperature and green in colour. Oil viscosity varies between 20 and 35 mPa.s at 25°C. Three activation energies which vary between 0.8 to 26.58 kJ.mol-1 were determined using Arrhenius’s equation. The melting points estimated by Differential Scanning Calorimetry were found to be between -22.0 and -12.0°C for the Soxhlet and Folch-extracted oils. Bligh and Dyer oil have three melting points at -36.2, -15.2 and 33.7°
A study on gumbo seed grown in Congo Brazzaville for its food and industrial applications
Proximate composition, energy content and mineral concentrations of okra seeds grown in two localities of Congo Brazzaville were investigated. The paper also reports the physicochemical characteristics of the oil extracted from the seeds. Ash was highest (5.84±0. 2%) in Dolisie okra seeds (DOS) followed by Brazzaville okra seeds (BOS) with a value of 5.52±0.34%. Protein ranged from 25.48±0.57% in DOS to 23.73±0.35% in BOS. Crude fat content is of 29.31±0.83% for BOS and 25.71±0.44 % for DOS. Totalcarbohydrates were generally high in all the seeds and ranged from 31.84% in BOS to 231.27% in DOS. The seeds were found to be good sources of minerals. Phosphorus (1755.95–1464.87 mg/100 g), magnesium (3895.67–2743.5 mg/100 g) and potassium (124.59-116.05 mg/100 g), were highest in two okra seeds cultivars. The physical properties of the oil extracts showed the state to be liquid at room temperature and the colour to be golden-yellow, in general. Thermal analysis show that fatty acids melting point was lowest ranged between -25°C and +6.55°C. Gas liquid chromatography revealed thatthe major fatty acid was linoleic acid (34.89-44%), palmitic acid (25.2-28.3%) and oleic acid (21.9-24.08%). Abelomschus esculentus seeds oil (AESO) content long chain poly unsaturated acids aseicosapentanoic acid (EPA) and docosahexaenoic acid (DHA) and erucic acid (1.1–4.1%). It can be inferred that the oil seeds investigated are good sources of crude fat, crude protein, ash and minerals. The oil extracts exhibited good physicochemical properties and could be useful as edible oils and for industrial applications
Influence of yeast and frozen storage on rheological, structural and microbial quality of frozen sweet dough
The aim of the present study was to investigate the effect of yeast content and frozen storage (9 weeks at -40°C) on the structural and rheological parameters, and fermentative activity of frozen sweet dough. Two types of dough were studied (to estimate dough shelf life): simple yeasted dough (SY) and double yeasted dough (DY). Fermentative activity (yeast viability, gassing power, and dough volume), rheological and textural parameters were assessed for frozen sweet doughs. These effects were explored by different and complementary methods: Fourier transform infrared (FTIR), dynamic rheology, texture profile analysis (TPA) and differential scanning calorimetry (DSC). The data showed that the longer the frozen storage time at -40°C, the higher the decreased of frozen sweet dough quality. The rheological attributes such as hardness, ΔS, springiness, tan δ and yeast activity declined significantly during frozen storage. This modification led to lower specific volume of frozen sweet dough during proofing. The observed changes of the frozen sweet doughs rheological properties after thawing may be attributed to the damage on the gluten cross-linking, mainly produced by the ice crystallization during frozen storage. The storage effect was particularly concentrated in the first 27 days of storage. © 2011 Elsevier Ltd. All rights reserved.Fil: Meziani, Smail. Coco LM Company (Maison Alsacienne de Biscuiterie); Francia. Nancy UniversitĂ©. Laboratoire d’IngĂ©nierie des BiomolĂ©cules; FranciaFil: Jasniewski, Jordane. Nancy UniversitĂ©. Laboratoire d’IngĂ©nierie des BiomolĂ©cules; FranciaFil: Ribotta, Pablo Daniel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto de Ciencia y TecnologĂa de Alimentos CĂłrdoba. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Instituto de Ciencia y TecnologĂa de Alimentos CĂłrdoba; ArgentinaFil: Arab-Tehrany, Elmira. Nancy UniversitĂ©. Laboratoire d’IngĂ©nierie des BiomolĂ©cules; FranciaFil: Muller, Jean-Marc. Coco LM Company (Maison Alsacienne de Biscuiterie); FranciaFil: Ghoul, Mohamed. Nancy UniversitĂ©. Laboratoire d’IngĂ©nierie des BiomolĂ©cules; FranciaFil: Desobry, StĂ©phane. Nancy UniversitĂ©. Laboratoire d’IngĂ©nierie des BiomolĂ©cules; Franci
Effect of freezing treatments and yeast amount on sensory and physical properties of sweet bakery products
The frozen bakery market has grown significantly in developed countries over the past decade. Of the available preservation technologies, freezing has been recognized as an excellent method of preserving the quality characteristics of bakery products. The aim of this work was to study the influence of freezing conditions (-20, -30, -40 °C and cryogenic immersion) and yeast content on the sensory and physical properties in the final baked product (Kougelhopf). Physical parameters such as specific volume, moisture, hardness, gas cells distribution and size were determined experimentally. A sensory evaluation (appearance, color, flavor, taste, texture and overall acceptability) was performed in Kougelhopf obtained from fresh and frozen sweet doughs. The experimental results showed that high freezing rates were correlated with more extended damage, yeast activity loss and lower Kougelhopf specific volume. The freezing rate also influenced the gas cells number and size. It was shown that increasing yeast in frozen sweet doughs improved the overall quality of Kougelhopf compensating for the loss of yeast activity during the freezing process. Kougelhopf produced from sweet dough with higher yeast content (DY) presented a higher specific volume, whereas freezing rate increases its hardness. Sensory tests confirmed that experimental results were detected by panelists. © 2012 Elsevier Ltd. All rights reserved.Fil: Meziani, Smail. Coco Lm Company (maison Alsacienne de Biscuiterie); Francia. Laboratoire D'ingĂ©nierie Des BiomolĂ©cules; FranciaFil: Kaci, Messaouda. Laboratoire D'ingĂ©nierie Des BiomolĂ©cules; FranciaFil: Jacquot, Muriel. Laboratoire D'ingĂ©nierie Des BiomolĂ©cules; FranciaFil: Jasniewski, Jordane. Laboratoire D'ingĂ©nierie Des BiomolĂ©cules; FranciaFil: Ribotta, Pablo Daniel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto de Ciencia y TecnologĂa de Alimentos CĂłrdoba. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Instituto de Ciencia y TecnologĂa de Alimentos CĂłrdoba; ArgentinaFil: Muller, Jean-Marc. Coco Lm Company (maison Alsacienne de Biscuiterie); FranciaFil: Ghoul, Mohamed. Laboratoire D'ingĂ©nierie Des BiomolĂ©cules; FranciaFil: Desobry, StĂ©phane. Laboratoire D'ingĂ©nierie Des BiomolĂ©cules; Franci
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