Application d'une méthodologie expérimentale à l'étude du diagramme ternaire d'un gel

Nous avons montré sur l'exemple d'un gel, mélange de trois constituants (C12–C15 Alcohols Benzoate, Cyclomethicone et Ethylene Vinyl Acetate Copolymer) qu'il est possible d'optimiser une formulation en un nombre preécis d'essais en faisant appel à une stratégic expérimentale optimale. Le gel avait déjàétéétudié par Chang,¹ mais par approches successives.
Nous avons utlisé les matrices d'expériences développées dans le cas des mélanges par Scheffe sous le nom de 'reseaux-simplex'. Prévoyant des intéractions de 2éme ordre entre les constituants nous avons retenu le modéle appelé'cubique réduit'. Cette approche permet l'exploration systémique de tout le domaine.
Les réponses étudiées sont la compatibilité (gel homogène ou non), la consistance, la blancheur et le coût. Le meilleur gel étant celui qui se rapproche le plus de la vaseline.
A partir des résultats, nous avons tracé des courbes d'isoréponse en blancheur, consistance et coût. La superposition des diagrammes conduit à la détermination d'une zone où les réponses sont optimales.
En ajoutant la réponse supplémentaire: 'facilité d'étalement sur la peau'on arrive au meilleur gel avec un nombre réduit d'essais.
La même méthode s'appliquerait à des mélanges de plus de trois constituants.
Study of a ternary diagram gel according to a methodology of experimental research     

Radiosity for dynamic scenes in flatland with the visibility complex

The radiosity method is particularly suitable for global illumination calculations in static environments. Nonetheless, recent applications of image synthesis such as architectural simulation or lighting design require the ability to modify environments. Previous methods have attempted to deal with dynamic environments (environments where the geometry, the material properties, etc., can change)but still suffer some limitations in the case of moving objects. One of the main problems remaining is the efficient and accurate detection of which form factors must really be recomputed, since their calculation is the most time-consuming part of the radiosity method. To correctly understand and solve this problem, we start with a method in 2D for polygonal scenes using the visibility complex. It is a powerful data structure representing the visibility relationships between objects in the plane. We have developed and implemented an algorithm which uses this structure to efficiently compute the discontinuity mesh and the form factors for static scenes. We also propose an extension to our algorithm to efficiently update only the modified form factors when an object is moving. This approach enhances our understanding and will hopefully lead to efficient solutions in 3D.     

Adjustment of Nonlinear Models for Lignin and Its Degradation Products during the Aging of Armagnac

Changes in lignin and in its degradation products, namely aromatic acids and aldehydes, were monitored in Armagnac brandies stored in old or new barrels. The concentration of these substances was always higher in the brandies aged in new barrels than in those aged in older barrels. Among the various mathematical models proposed, the parabolic function always showed the least residual error. A parameter n that might characterize the age of a barrel was defined.     

ELECTROSPRAY MASS SPECTROMETRY ANALYSIS OF MYOGLOBIN IN MINCED MEAT PRODUCTS

The heat stability of myoglobin in burgers was studied by Electrospray Mass Spectrometry (ESMS). Burgers containing mixtures of meat and other adjuncts were cooked and myoglobin was extracted with a urea solution. The extracts were analyzed by ESMS and the globin chain of myoglobin was the major peak as myoglobin dissociates to heme and globin during ionization. As time of cooking increased, the globin peak became broader with a tail at high mass indicating the presence of other unidentified components. Extracts from burgers made with one meat species showed one globin peak with a molecular weight characteristic of the species. However, when mixtures of beef-lamb and beef-pork were analyzed only beef-myoglobin globin was detected and no trace of globins from the other species could be detected. The presence of curing salt and glucose had an adverse effect, such that reproducible analysis of globins was not possible.     

Color Retention in Red Chile Powder as Related to Delayed Harvest

Color retention in Chile powder was studied using two mildly pungent long red Chile (Capsicum annuum L.) cultivars, ‘New Mexico 6–4’ and ‘NuMex R Naky’. Pods of different maturities were harvested immediately after the first severe fall freeze and again 4 and 8 wk after the freeze. After each harvest pods were dried, ground, and immediately analyzed for color. Powder was stored at 2°C and re-analyzed for color at 4 wk intervals. Color loss in whole pods from the field and the stored powder showed linear and quadratic trends. Initially, delaying harvest resulted in color loss in red Chile but color in powder from later harvests was more stable and was retained better after 8 wk storage than powder from the first harvest after the same length of time.     

Effect of Hemicellulose on Viscosity of Rice Flour

Effects of water-soluble bran and endosperm hemicelluloses on Brabender viscosity curves of intact and hemicellulose-free rice flour were examined over the complete cooking and cooling curves. Amylograph curves of long- and medium-grain rice flour with added bran hemicellulose showed no difference; both had lowered viscosity. Similarly, addition of a ferulic acid-containing polysaccharide isolated from bran hemicellulose to the intact rice flour also lowered viscosity. This complex polysaccharide may, therefore, be responsible for at least part of the viscosity reduction upon addition of the bran hemicellulose. Amylograph curves of long- and medium-grain rices were different when endosperm hemicellulose was added back to the intact flour. When hemicelluloses were completely removed and increasing amounts added back, changes in viscosity correlated with the amounts of added hemicellulose.     

ETIOLOGY OF ALCOHOLISM.

A COMPARISON OF M. C. JONES' (SEE 42:5) FINDINGS WITH THE OTHER LONGITUDINAL RESEARCH REPORTED IN ALCOHOL STUDIES (THE MCCORDS' WORK) POINTS UP SOME CHALLENGING AREAS OF AGREEMENT IN DESCRIBING THE PREADOLESCENT AND ADOLESCENT BEHAVIORAL CHARACTERISTICS OF THOSE WHO LATER BECOME PROBLEM DRINKERS. THE POTENTIAL PROBLEM DRINKER APPEARS TO BE A BOY WHO HAS LESS THAN ADEQUATE CONTROL OVER IMPULSIVITY, WHO OVERPLAYS THE ACTIVE MASCULINE ROLE, AND WHO TENDS TO USE DENIAL AS A MAJOR LINE OF EGO DEFENSE. IT IS STRIKING THAT 2 INDEPENDENT STUDIES, DIFFERENT IN RESEARCH POPULATION AND IN METHODOLOGY, AGREE IN DESCRIBING SOME ASPECTS OF PSYCHOLOGICAL PREDISPOSITION TO ALCOHOLISM. (PsycINFO Database Record (c) 2010 APA, all rights reserved)