Face Sheet/core Debonding In Sandwich Composites Under Static And Fatigue Loading

Delamination growth due to face sheet/core debonding is a major concern due to its inherent weakness in sandwich composites which can be exacerbated due to the presence of flaws. In this research work The primary objective of this research was to characterize the delamination crack growth behavior in E-glass face sheet/polyurethane foam core sandwich composite with pre-existing initial delamination crack at a face sheet/core interface under static and fatigue for mode I and mixed mode loading. For mode I static loading two types of delamination experiments, namely T-peel test and wedge test were implemented to evaluate fracture toughness in polyurethane foam core sandwich composites. It is shown that both tests can provide reliable values for mode I fracture toughness. Two analytical solutions for models (double cantilever beam (DCB) specimen and tilted debond specimen (TDS) test) based on elastic foundation analysis are modified and validated for mode I loading. For mixed mode static loading, mixed mode bending (MMB) specimen was employed to evaluate energy release rate, compliance and global mode ratio for composite under investigation. It was observed that energy release rate, compliance and global mode ratio increases with increase in crack length. For fatigue life is investigated for constant displacement amplitude for mode I and mixed mode loading using single cantilever beam (SCB) specimen and mixed mode bending (MMB) specimen, respectively. The fatigue test results are in terms of crack growth rate versus energy release rate and Paris law constants are estimated to predict failure of polyurethane foam core sandwich composite. Decreasing crack growth rate as a function of fatigue cycles was attributed to stress relaxation at delamination crack tip. The effect of lever arm distance (c) for mixed mode loading is investigated. It is shown that both compliance and energy release increases with an increase in the lever arm distance (c) and global mode ratio decreases and mode I become more dominant. The polyurethane foam core sandwich composites results are new. The energy release rate and Paris law constants for a growing crack are low for polyurethane foam core sandwich composites as compare to PVC core sandwich composites. Finally, finite element analyses are conducted to validate the experimental results. The results obtained from experiments and finite element analysis showed good agreement

A first step towards a dependability framework for smart environment applications

Smart environments will consist of a large number of heterogeneous devices that communicate to collaboratively perform various tasks for users. We propose a novel dependability framework to increase availability and reliability of smart environment applications. We argue that the key step in achieving high dependability is to predict faults before they occur. Many statistical fault prediction techniques have been proposed for smart environment applications. Selecting the best one among these techniques involves performance assessment and detailed comparison on given metrics. We present a linear regression-based prediction model to predict the remaining battery lifetime of a device to prevent faults due to low battery. Further, we discuss the proposed dependability framework, the basic approaches and the corresponding mechanisms to achieve our long-term research goal. We envision that dependability framework will reduce maintenance costs of large-scale smart environments and increase the dependability of smart environment applications

Explorative Study of Parents Education Effect on the Socialization of their Children (A Case of District Muzaffar Garh)

The Present research was conducted on “Explorative study of Parents Education effect on the Socialization of their Children” (A case of District Muzaffar Garh). In Pakistan, Education is overseen by the government, NGOs and different private sector. The education system in Pakistan is generally divided into five levels: primary (grades one to five), middle (grade six to eight), high (grade nine to ten), intermediate (grade eleven to twelve) and universities programs (undergraduate and graduate degree). The main focus of this research was to identify the major factors, those effect on the socialization of the children. Despite of all factors, parent’s education has significant effect on the socialization of their children. Due to parent’s low literacy rate, due to their low level of education, due to some economical, cultural and organizing issues families have bad effect on their children socialization. So in this research those problems or issues were analysis and highlighted those create hurdles in the socialization of the children. Data analysis and testing of hypothesis show that educated parents socialize their children in well manner way as compare to uneducated parents. Educated parents children are more active and take part not only in educational activities but also in the other activities. Data also showed that some time teachers do hard work but the back up support does not come from the parents. The reason is that the illiterate /lesser educated parents do not realize the value of education Keywords: Affection, Level, Education, Socialization, Participant 

Dairying and whole-farm economics of crop-livestock farming systems - comparing arid and irrigated districts of Punjab, Pakistan

Dairying is an important component of Pakistan’s mixed crop-livestock farming systems. The national economy engages some 8.8 million small-scale producer households. The country produces more milk than any other except for the United States and India. Yet little is known about small-scale producer microeconomics to inform policy development for improving their welfare. In this paper we aim to identify the whole farm profitability of small agricultural households, with a specific focus on milk production. We compare two contrasting agro-ecological regions within Pakistan’s Punjab (irrigated Okara and rain-fed Bhakkar) using results for a single 2008-09 fiscal year of production for 212 farms. Net farm profits, taking long-run opportunity costs of labour and capital into account, showed only 10 per cent of these farms to be profitable in either district, though short-run profits, accounting for cash costs only, showed positive whole farm gross margins for 90 per cent and 80 per cent of farms in Okara and Bhakkar, respectively. The returns on assets (at 2.78 per cent and 0.53 per cent for the two districts) was lower than the national average return on savings (9 per cent). For dairy enterprises, total costs were higher than incomes; so many farms (70 per cent and 60 per cent, respectively) were assessed as making losses. Given the low opportunity costs of feeds (often crop residues) and of labour (6.2 per cent unemployment) and the high rate of inflation (11.8 per cent), returns on factors of production including labour and capital, may not be lower than international standards. There is a need, however, to raise the dairy industry’s overall productivity to make dairying viable; and to identify an optimal land and livestock combination that is profitable and commercially viable