Simulation of progressive damage in composites using the enhanced embedded element technique

Analysis of complex composite structures requires a fine contiguous mesh of threedimensional (3D) solid elements. The embedded element technique is a promising technique for predicting stiffness and stress. This paper presents a new method for enhancing the embedded element with continuum damage mechanics methods for predicting the evolution of damage in fiber reinforced composite structures. Comparison of the model prediction with experimental results reveals an excellent correlation between the tensile strength of quasi-isotropic laminate with an open hole. The embedded element technique allows the fiber reinforcement and matrix domains to be meshed independently and failure is evaluated separately in each domain. The enhanced embedded element approach allows the failure modes to be observed, specifically, the evolution of matrix cracking and fiber rupture. Compared to the traditional contiguous mesh finite element method, the present modelling technique demonstrates a clear advantage in predicting the experimentally observed failure modes and accurate characterisation of intralaminar fracture.

The Effects of Progressive Resistance Training on Obstructed-Gait Tasks in Community-Living Older Adults

This study examined the effects of improved strength on an obstacle course (OC) simulating gait tasks commonly encountered by community-living older adults. Forty-five adults (mean age 68.2 +/- 1.5 years) were randomly assigned to a control (10 women, 5 men) or an experimental group (EXP; 19 women, 10 men) and trained 3 days/week for 12 weeks.

A mesh based anycast routing protocol for ad hoc networks

Ad hoc networks became a hot topic recently, but the routing algorithm of anycast in the ad hoc networks has not yet been much explored. In this paper, we propose a mesh-based anycast routing algorithm (MARP) for ad hoc networks. The proposed routing model is robust and reliable, which can solve the unsteady topology problem in ad hoc networks. The future work is discussed at the end of this paper.

Finite element modelling of metallic tubular crash structures with an explicit code

Numerous experimental studies have been carried out to investigate the collapse of tubular metallic crash structures under axial compression. Some simple theoretical models have been developed but these often assume one type of progressive collapse, which is not always representative of the real situation. Finite Element (FE) models, when further refined, have the potential to predict the actual collapse mode and how it influences the load-displacement and energy absorption characteristics. This paper describes an FE modelling investigation with the explicit code LS−DYNA. An automatic mesh generation programme written by the authors is used to set up shell and solid element tube models. Mesh specification issues and features relating to the contact and friction models are discussed in detail. The crush modes, load-deflection characteristics and energy absorption values found in the simulations are compared with a reasonable degree of correlation to those observed in a physical testing programme; however, improvements are still required.

Object oriented finite element analysis: a distributed approach to mesh generation

The object-oriented finite element method (OOFEM) has attracted the attention of many researchers. Compared with the traditional finite element method, OOFEM software has the advantages of maintenance and reuse. Moreover, it is easier to expand the architecture to a distributed one. In this paper, we introduce a distributed architecture of a object-oriented finite element preprocessor. A comparison between the distributed system and the centralised system shows that the former, presented in the paper, greatly improves the performance of mesh generation. Other finite element analysis modules could be expanded according to this architecture.

Progressive discourse in mathematics classes - the task of the teacher

This paper uses data from two mathematics lessons to explore the nature of progressive discourse and examine critical features of teacher actions that contribute to mathematics classrooms functioning as communities of inquiry. Features found to promote progressive discourse include a focus on the conceptual elements of the curriculum and the use of complex, challenging tasks that problematised the curriculum; the orchestration of student reporting to allow all students to contribute to progress towards the community's solution to the problem; and a focus on seeking, recognizing, and drawing attention to mathematical reasoning and justification, and using this as a basis for learning.

Stop taxing happiness : a new perspective on progressive taxation

The development of taxation law and policy has been driven largely by economic considerations and economic theory. Underlying this is the assumption that money is important to human well-being and is in fact the most important thing in this regard. Recent empirical studies of human well-being disprove this assumption. Money has only a limited bearing on happiness. It follows that economic arguments that have long shaped taxation law and policy should be discarded in preference for recent learning concerning what really matters to people. The results of the recent studies have significant implications for the manner in which we should raise tax. We argue that for income under approximately $20,000 the rate should be 0 to 5 per cent. For income between $20,000 to $50,000 the rate should be about 15 per cent. Incomes beyond this level should taxed at approximately 75 per cent. There is no reason to have further rate differentials.

Effects of high-intensity progressive resistance training on self-reported health status in older persons with type 2 diabetes

Purpose: To evaluate the influence of high-intensity progressive resistance training (PRT) on self-reported physical and mental health in older persons with type 2 diabetes.

Methods: We performed a 12-month RCT with 36 overweight men and women with type 2 diabetes (aged 60-80 years) who were randomly assigned to a moderate weight-loss diet plus PRT (PRT&WL) or a moderate weight-loss diet plus a control (stretching) program (WL). Gymnasium-based training for 6 months was followed by an additional 6 months of home-based training. The SF-36 (v1) questionnaire was used to obtain physical (PCS) and mental (MCS) health component summary scores at baseline, 6 and 12 months.

Results: Subject retention was 81% and 72% after 6 and 12 months respectively. Exercise adherence during gymnasium- and home-based training was 88% and 73% for the PRT&WL group, and 85% and 78.1% for the WL group respectively. In a regression model adjusted for age and sex, PCS improved in the PRT&WL group compared to the WL group after 6 months of gymnasium-based training (2.3 versus -2.0, p = 0.05), which persisted after 12 months training (0.7 versus -4.1, p = 0.03). There were no between-group differences at 6 or 12 months for the MCS.

Conclusion: High-intensity PRT was effective in improving self-reported physical health, but not mental health. PRT provides an effective exercise alternative in lifestyle management for older adults with type 2 diabetes.

Satisfaction with services among people with progressive neurological illnesses and their careers in Australia

Abstract The current study investigated the types of support networks and services accessed by people with progressive neurological illness, as well as the assessment of the usefulness of these services. The participants were 25 people with multiple sclerosis, 15 people with motor neurone disease, 23 people with Parkinson's disease, and six people with Huntington's disease. Twenty-eight professionals who worked with people with these illnesses and 41 carers of people with these illnesses also were interviewed. The results demonstrate that all of the groups of respondents indicated a strong need for basic services (e.g. home help), as well as specialized services (e.g. support groups). These two services also were identified as the most useful services by all of the groups of respondents. The similarities and differences between the groups, as well as the patients and carers, are examined. These findings demonstrate the importance of providing basic services for people with progressive neurological illnesses.

Energy efficient, fully-connected mesh networks for high speed applications

Fully-connected mesh networks that can potentially be employed in a range of applications, are inherently associated with major deficiencies in interference management and network capacity improvement. The tree-connected (routing based) mesh networks used in today’s applications have major deficiencies in routing delays and reconfiguration delays in the implementation stage. This paper introduces a CDMA based fully-connected mesh network, which controls the transmission powers of the nodes in order to ensure that the communication channels remain interference-free and minimizes the energy consumption. Moreover, the bounds for the number of nodes and the spatial configuration are provided to ensures that the communication link satisfies the QoS (Quality of Service) requirements at all times.

A longitudinal study of economic pressure among people living with a progressive neurological illness

Objectives: Previous research has examined costs associated with progressive neurological illnesses, but has not examined predictors of economic pressure, or quality of life (QOL). The aim of the current study was to examine the predictors of both economic pressure and QOL among people with a range of progressive neurological illness.

Method: Participants were 257 people with motor neurone disease, Huntington’s disease, multiple sclerosis and Parkinson’s.

Results: High levels of cut backs in spending predicted economic pressure for all groups. Economic pressure predicted QOL at 12-month follow-up for all groups except Parkinson’s. For Parkinson’s, predictors of QOL were long duration of illness, illness-related expenses and cut backs in spending. Cut backs in spending, and not income or expenses, were the most important predictor of economic pressure. QOL was predicted by high levels of economic pressure for most of the illness groups.

Discussion: The implications of these findings are discussed. They suggest that cut backs in spending, as opposed to income and expenses, are important factors to focus on assisting people to adjust to the changes to their financial situation that frequently occurs after developing one of these progressive neurological illnesses.

A comparison of mood and quality of life among people with progressive neurological illnesses and their caregivers

The current study was designed to investigate differences in mood and a range of QOL domains among 423 patients and 335 caregivers of people with motor neurone disease (MND), Huntington’s disease (HD), Parkinson’s, and multiple sclerosis (MS). Patients and caregivers completed an anonymous questionnaire that evaluated their mood (anxiety, depression, fatigue, confusion) and QOL (physical, psychological, social, environment). The results demonstrated that caregivers of people with MND and HD experienced most problems with their mood and QOL compared to caregivers of people in the other illness groups. There were few differences in mood or QOL between patients and caregivers. Patients generally showed greater confusion, physical impairment, and psychological maladjustment. The findings suggest that educational and intervention programs need to be developed to help both patients and their caregivers to adjust and cope with these illnesses, particularly caregivers of people with MND and HD.