Prosocial and aggressive behavior occurrence in young athletes: Field research results in six European countries

Aggression and violence among youth areresearched as social phenomena in sport. This paper was designed to determine the occurrence of these behaviors as well as prosocial behaviorsamong young athletes. The current paper is a research report aiming to detect the frequency of aggressive behavior, social exclusion, prosocial behavior and cohesion in the youth environment, the frequency of personal experience of peer violence or social exclusion, and to evaluate cross-national differences in terms of occurrence of these phenomena. The field research was conducted in six European countries (Austria, Bosnia and Herzegovina, Croatia, Italy, Lithuania, and Serbia) on a sample of 482 children aged 6 to 16. The conducted questionnaire consisted of pre-existing scales and measures for specific behaviors and social aspects that formed the Youth Environment Assessment and Youth Characteristics Questionnaire. Previous personal experience of violence and social exclusion determined groups in the sample. One-way ANOVA and discriminant analysis were conducted to compare various variables and groups within the sample. The results have shown that aggressive and social exclusion behaviors are rare or very rare, predominantly in the form of verbal aggression in the sports club environment. The results of the conducted discriminant analysis indicate that prosocial and cohesion behaviors occur "quite often" to "often" among sports club athletes' samples. The percentage of athletes who have had personal experience of violence or social exclusion in the last two years and whose feeling of hurt by that experience was assessed as "a lot" or "fully" on the measurement scale is estimated to be approximately 25%. Mild cross-national differences emerged in the overmentioned variables, probably due to the sample specificity, or to cultural variety. The results indicate the need for longitudinal research on this topic since the sport is an environment in which cohesion can be developed among young athletes, but it is not free from social exclusion or aggression

A fundamental study of the behaviour of clay-brick fines in autoclaved calcium silicate based building products

University of Technology, Sydney. Faculty of Engineering.NO FULL TEXT AVAILABLE. This thesis contains 3rd party copyright material. The hardcopy may be available for consultation at the UTS Library.NO FULL TEXT AVAILABLE. This thesis contains 3rd party copyright material. ----- This research project studied the behaviour of clay-brick waste (CB) in combination with Ordinary Portland Cement (OPC) in hydrothermal environment. The aims of this study were to establish the hydrothermal chemistry involved during autoclaving when CB were used as a raw material for the production of autoclaved calcium silicate based building products and to evaluate the suitability of CB as a possible cement replacement. The compositional regions studied cover the areas 20-60 wt % SiO2 and 3.5-34 wt % Al2O3 in the CaO-Al2O3-SiO2-H2O system. Mixes were prepared with OPC and with either four different CB types or one quartz sand. The samples were cured at 180 °C for 7.5 hours or at 150 °C for 7.5 selected samples. Different curing temperatures were used to investigate the effect of curing temperature on the compressive strength and phase development. In a similar manner, different cement types were used to investigate the effect of different cement types on compressive strength, degree of carbonation and phase development. Evaluations of mechanical properties of autoclaved samples were conducted on the blends. Compressive strength testing was conducted on all blends while determination of drying shrinkage and degree of carbonation was carried out on selected blends in the region where the strength was found to be optimum. The evaluation of phase development in all mixes was carried out by employing a combination of experimental techniques including X-ray diffraction (XRD), differential thermal analysis and thermogravimetric analysis (DTA-TGA), scanning electronic microscopy (SEM) and wet chemical methods. Overall, more than 80 different blends were analysed for microstructural and macrostructural (engineering) properties. 1.1 nm tobermorite (tobermorite) along with C-S-H, hydrogarnet, portlandite (CH) and alpha-dicalcium silicate hydrate phase (α-C2SH), were established as the critical phases in relation to strength development, drying shrinkage and degree of carbonation. With regards to strength development it was concluded that tobermorite was the principal contributor since an increase in tobermorite amount corresponded to an increase in the compressive strength. Presence of α-C2SH and CH favoured strength decrease with α-C2SH reducing the strength significantly and CH delaying the tobermorite formation. There is also evidence that a decrease in hydrogarnet formation favoured strength increase. The study also established that tobermorite, despite its ability to perform as a strong binder, was susceptible to carbonation and responsible for an increase in drying shrinkage. The main phases that restrained drying shrinkage and increased resistance to CO2 attack were CH, hydrogarnet and α-C2SH, when present. From experimental data of different curing temperatures (150 °C versus 180 °C) it was established that the amount and morphology of tobermorite, hydrogarnet and CH were amenable to control through appropriate CB additions and curing temperatures. These findings are significant from the viewpoint of the durability of commercial, hydrothermally cured products and their relevance to geothermal oil-well applications. Overall, the use of CB as a cement replacement for the production of autoclaved cement- based building products was demonstrated to be a viable option. OPC:CB blends autoclaved at 180 °C exhibited comparable or better mechanical properties than their OPC: quartz counterparts that are currently used by industry

Brick waste a supplementary cementing material in autoclaved building products

Fired-clay products such as bricks, tiles and pavers, are made in large volumes throughout the world and widely used as construction materials. A significant proportion of them end up being a waste material during either their production process or the demolition of buildings. High pressure steam curing or autoclaving is a proven and versatile method for utilising supplementary cementing materials such as fly-ash and blast furnace slag for the manufacture of cement-based building products. In this investigation, autoclaving has been used to treat blends of ordinary Portland cement with different amounts of ground brick waste. Our experimental data demonstrate the viability of this waste to be used by the construction industry as a supplementary cementing material. The paper presents results of salient engineering properties in relation to microstructural characteristics

Strength development in autoclaved blends made with OPC and clay-brick waste

This article reports findings on the strength development of autoclaved OPC-clay-brick blends, where a variety of clay-brick types were used. The strength variations are explained in terms of differences in chemical and mineralogical properties of clay-brick as well as the phases formed during autoclaving. An overall increase in strength was characteristic for 30-60 mass% for all clay-brick type additions. The optimum compressive strengths were achieved at 50 mass% clay-brick additions, where highly crystalline 1.1 nm tobermorite coexisted with "fibrous C-S-H". © 2004 Elsevier Ltd. All rights reserved

Strength development in hydrothermally treated OPC:CB systems

The strength developments of hydrothermally cured blends comprised of ordinary Portland cement (OPC) and clay-brick waste (CB) and treated at 180°C under saturated steam for 6 h were studied. Two types of CB, of different chemical and mineralogical make-up, were used to make OPC-CB blends where 10 to 80 mass% CB replaced OPC. The nature of the hydration products formed after autoclaving were subsequently investigated by using a combination of DTA, DTG, TG, X-ray diffraction, and wet chemical techniques. The modes of the hydrothermal reactions between OPC and the two types of CB, as well as the nature of the main binder belonging to the tobermorite family, are discussed and related to the development of the strength of the autoclaved articles. © 2005 Akadémiai Kiadó, Budapest

Use of DTA-TG in the evaluation of autoclaved cement-based systems. Part I. Cement-brick waste blends

Fired-clay products such as bricks, tiles and pavers, are made in large volumes for use in a variety of construction applications throughout the world. A significant proportion of them ends up being a waste product either during their production process or the demolition of buildings. High pressure steam curing or autoclaving has proven extremely versatile for the manufacture of cement-based building products incorporating waste materials such as fly-ash and blast furnace slag. The nature of hydration products in an autoclaved cement based system incorporating different amounts of finely ground brick waste was investigated by means of thermal analysis and XRD, and is the subject of this paper