The evolution of shrinkage strain of pet-mortar composite eco-materials

Concretes and mortars are subjected to several kinds of shrinkage strains which represent the volumic variations resulting from the cement hydration and are governed by various physical and chemical aspects. The use of polyethylene terephthalate PET plastic wastes which are available in quantity and within low cost in our country yields a very important economic and environmental impact in the construction industry. Thus, we are interested to investigate the effect of PET volumetric additive amounts for cement substituting and for the behavior of the total, drying and autogenous shrinkage. Comparison study of obtained experimental results with codale prediction models were performed according to Eurocode 2  (EC2) in order to analyze the evolution of shrinkage strain with PET-mortar  composite ages and for several rates of PET waste additions. According to obtained results, PET additions acts to reduce shrinkage strains of PET-mortar composites which promote the use of these modified mortar Eco-materials in the field of construction industry.Keywords: Composite Eco-materials; Cement substitution; Shrinkage strain; PET waste; EC2

Feuilles sèches de Figuier et foin de Sulla (Hedysarum flexuosum) en alimentation du lapin en engraissement

Notice a Reprendre pas de Clé UT au 5 Mai 201785 Algerian white population rabbits were used to study the effect on the growth performances of fig-tree (Ficus carica, 12.8%, 30.6% and 15 % DM respectively of CP, NDF and ADL) leaves incorporated in pelleted diets in association with Sulla hay (Hedysarum flexuosum). At weaning (35 d, 674±390 g), the rabbits were divided in three groups (individually caged) and received ad libitum one of the three diets during six weeks. The control (T, n=25), diet was classic diet and content barley, dehydrated alfalfa, soya bean meal and wheat bran. The experimental diets were formulated to contain 25% of Sulla hay and either 15% (F1, n =30) or 30% (F2, n =30) dried fig tree leaves in total replacement of dehydrated alfalfa and barley. The diet F1 contained also wheat bran to contain only raw materials available locally. During the whole period (35-77 d), feed intake was at the same level with the three diets (121.3 ± 6.5 g/d), as well as growth (35.3 ± 2.4g/d) and feed conversion ratio (3.37 ± 0.21). According, fig-tree leaves (Ficus carica) could be incorporated in pellet diet for fattening rabbits associated with Sulla ( Hedysarum flexuosum), in total replacement of barley, dehydrated alfalfa and eventually soya bean meal to contain only locally available raw materials. They permitted substantial performances as those of control diet without negative effect on health and the zootechnic performances.85 lapins de population locale blanche ont été utilisés pour étudier l’effet sur les performances de croissance de l’incorporation, dans l’aliment granulé, de feuilles de Figuier (Ficus carica ; 12,8% ; 30,6% et 15 % MS respectivement de PB, NDF et ADL) associées au foin de Sulla (Hedysarum flexuosum). Au sevrage (35 j, 674±390 g), les lapins ont été répartis en trois lots homogènes, logés individuellement et ont reçu ad libitum un des trois aliments durant 6 semaines. Le témoin (T, n=25), un aliment classique, contenait de la luzerne déshydratée, du son de blé, de l’orge et du tourteau de soja. Les deux aliments expérimentaux contenaient 25% de foin de Sulla et soit 15% (F1, n =30) soit 30% (F2, n =30) de feuilles séchées de Figuier (FF), en remplacement total de la luzerne et de l’orge. L’aliment F1, équilibré avec du son de blé, ne contenait que des matières premières disponibles localement.Durant la période globale (35-77 j), la consommation a été similaire entre les trois aliments (121 ± 6,5g/j), ainsi que la vitesse de croissance (35,3 ± 2,4g/j) et l'indice de consommation de l’aliment (3,37 ± 0,21). Ainsi, les feuilles de Figuier (Ficus carica) peuvent être incorporées dans l’aliment granulé pour lapins en engraissement associées à du foin de Sulla (Hedysarum flexuosum), en remplacement de l’orge, de la luzerne déshydratée et éventuellement du tourteau de soja pour ne contenir que des matières premières disponibles localement. Elles ont permis des performances appréciables au même niveau que celles de l’aliment témoin sans effets négatifs sur la santé et les performances zootechniques

Effect of Addition of PET in the Thermal Properties of Polymer-Mortar Composite Materials

The polymer-mortar composites are often used as low-cost promising materials for preventing or repairing various reinforced concrete structures. The Thermal behavior of the ¶building materials ¶is relevant to any use of concrete or composite, especially in relation to structures where it is desirable to have low thermal conductivity, dimensional stability, high specific heat and little or no decrease of stiffness upon heating. Although much work has been done on the effect of admixture and the mechanical properties of concrete or composite, relatively little work has been done on the thermal conductivity. So, Thermal conductivity (l), thermal resistance (R) and the surface coefficients of transmission (U) of polymer-mortar composites made up of mixtures of polyethylene terephthalate PET waste were measured. To determine the effect of the PET on the thermal conductivity of PET-mortar composites, PET was added as replacement for cement by decreasing the cement weights in the ratios of 2.5%, 5% and 7.5% by weight. The highest thermal conductivity of 1.45 W/mK was observed with the samples containing only plain cement. It decreased with the increase of PET as replacement for cement. The lowest value of thermal conductivity and the surface coefficient of transmission were obtained with the samples prepared with PET waste polymer at 7.5 % replacement of cement. The composites were also observed by DTA, MOP led to the positive identification of the products’. In this way, the results obtained highlight the beneficial effect of waste PET as thermal insulation in comparison with other insulation materials. In addition, the obtained PET-mortar composites would appear to be low-cost materials which would contribute to resolving some of the solid waste problems in addition to conserving energy

Investigating neuromagnetic brain responses against chromatic flickering stimuli by wavelet entropies

BACKGROUND: Photosensitive epilepsy is a type of reflexive epilepsy triggered by various visual stimuli including colourful ones. Despite the ubiquitous presence of colorful displays, brain responses against different colour combinations are not properly studied. METHODOLOGY/PRINCIPAL FINDINGS: Here, we studied the photosensitivity of the human brain against three types of chromatic flickering stimuli by recording neuromagnetic brain responses (magnetoencephalogram, MEG) from nine adult controls, an unmedicated patient, a medicated patient, and two controls age-matched with patients. Dynamical complexities of MEG signals were investigated by a family of wavelet entropies. Wavelet entropy is a newly proposed measure to characterize large scale brain responses, which quantifies the degree of order/disorder associated with a multi-frequency signal response. In particular, we found that as compared to the unmedicated patient, controls showed significantly larger wavelet entropy values. We also found that Renyi entropy is the most powerful feature for the participant classification. Finally, we also demonstrated the effect of combinational chromatic sensitivity on the underlying order/disorder in MEG signals. CONCLUSIONS/SIGNIFICANCE: Our results suggest that when perturbed by potentially epileptic-triggering stimulus, healthy human brain manages to maintain a non-deterministic, possibly nonlinear state, with high degree of disorder, but an epileptic brain represents a highly ordered state which making it prone to hyper-excitation. Further, certain colour combination was found to be more threatening than other combinations

Impact of caloric and dietary restriction regimens on markers of health and longevity in humans and animals: a summary of available findings

Considerable interest has been shown in the ability of caloric restriction (CR) to improve multiple parameters of health and to extend lifespan. CR is the reduction of caloric intake - typically by 20 - 40% of ad libitum consumption - while maintaining adequate nutrient intake. Several alternatives to CR exist. CR combined with exercise (CE) consists of both decreased caloric intake and increased caloric expenditure. Alternate-day fasting (ADF) consists of two interchanging days; one day, subjects may consume food ad libitum (sometimes equaling twice the normal intake); on the other day, food is reduced or withheld altogether. Dietary restriction (DR) - restriction of one or more components of intake (typically macronutrients) with minimal to no reduction in total caloric intake - is another alternative to CR. Many religions incorporate one or more forms of food restriction. The following religious fasting periods are featured in this review: 1) Islamic Ramadan; 2) the three principal fasting periods of Greek Orthodox Christianity (Nativity, Lent, and the Assumption); and 3) the Biblical-based Daniel Fast. This review provides a summary of the current state of knowledge related to CR and DR. A specific section is provided that illustrates related work pertaining to religious forms of food restriction. Where available, studies involving both humans and animals are presented. The review includes suggestions for future research pertaining to the topics of discussion

Valorization of mud from Fergoug dam in manufacturing mortars

The production of calcined mud, with pozzolanic properties, from the large quantities of sediments dredged from Algerian dams, could be a good opportunity for the formulation of high performance mortars and pozzolanic concretes, with lower costs and less greenhouse gas (CO2) emissions. The optimal temperatures selected for calcination were 750, 850 and 950 °C. The burning operation was continuous over a period of 3 h. Therefore, a series of physical, chemical, mechanical and microstructural analyses were conducted on sediment samples, collected from the waters of Fergoug dam. The results obtained from the analyses of the calcined mud, from the dam, allowed saying that mortars with different percentages of that mud represent a potential source of high reactivity pozzolanic materials