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BackgroundChina has the largest population of partially or completely disabled elderly people in the world. Although the disabled elderly people try to remain independent in their lives, many still need assistance from others. Failure to obtain sufficient assistance creates a situation of unmet need. Unmet needs of activities of daily living (ADL) for disabled elderly people pose significant risks for hospitalization and mortality and cause an increased economic burden on families and society. This study aimed to identify the prevalence and risk factors of unmet needs among the disabled elderly in China to guide government toward corrective action.MethodsA total of 303 older adults from 15 communities in Nanjing, China were recruited. The Barthel Index (BI) and Functional Activities Questionnaire (FAQ) were used to screen disabled elderly people from the communities. These disabled elderly participants were then investigated in terms of their unmet ADL needs, using an unmet needs assessment form, which had been adapted from the BI and FAQ. Additionally, the Zarit Burden Interview and Family Caregiver Task Inventory were used to survey the main caregivers. Finally, univariate analysis was first used to filter out candidate impact factors, and then, binary logistic regression analysis was used to adjust for cofounders and determine reliable risk factors.ResultsA total of 93.1% of the disabled elderly people in our study reported at least one unmet need. The prevalence of unmet needs for different ADL tasks ranged from 4.6 to 77.2%. The unmet needs with the highest percentages were using vehicles (77.2%), using stairs (73.1%), working on a hobby (72.1%), social interaction (62.6%) and ambulating (60.1%). The factors influencing unmet needs were related to the degree of disability in instrumental activities of daily living (IADL) (OR = 1.079, p ≤ 0.01), the relationship with caregivers (OR = 1.429, p ≤ 0.05) and the monthly income of caregivers (OR = 0.679, p ≤ 0.05).ConclusionDisabled elderly people living in communities had a high percentage of unmet needs for activities of daily life that required going outside the bedroom and involved spiritual aspects. Unmet needs increased with worsening disability status in IADL, more distanced relationships with caregivers and lower incomes of caregivers. Both government and caregivers should take more action to prevent or reduce unmet needs among the elderly.Electronic supplementary materialThe online version of this article (10.1186/s12877-018-0856-6) contains supplementary material, which is available to authorized users.

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Transmission tower-line system is a high-rise structure with low damping and it is therefore prone to strong wind excitation. In this paper, the control of wind-induced response of transmission tower-line system is carried out by using magnetorheological (MR) dampers. The effects of brace stiffness of damper are introduced and a multi-degree-of-freedom (MDOF) model is developed for both in-plane/out-of-plane vibration of transmission tower-line system. Two semi-active control strategies are proposed for the vibration mitigation of tower-line system. The first one is based on fixed increment of controllable damper force whereas the second one is a clipped-optimal strategy based on fuzzy control principle. The optimal parameters of the MDOF model of transmission line are investigated. A real transmission tower-line system constructed in China is taken as an example to examine the feasibility and reliability of the proposed approach. A parametric study is conducted for the effects of brace stiffness of MR damper, wind loading intensity, and parameters of MR fluids on the control performance. The results demonstrate that the incorporation of MR dampers into the transmission tower-line system can substantially suppress the wind-induced responses of transmission tower if the damper parameters are optimally determined. The performance of the two kinds of semi-active control approaches is better than that of a passive control approach.

The present paper describes the results from experimental and theoretical modelling studies on the behaviour of continuous carbon fibre/polymer matrix composites subjected to a relatively low-velocity or high-velocity impact, using a rigid, metallic impactor. Drop-weight and gas-gun tests are employed to conduct the low-velocity and high-velocity impact experiments, respectively. The carbon fibre composites are based upon a thermoplastic poly(ether–ether ketone) matrix (termed CF/PEEK) or a thermoset toughened epoxy matrix (termed CF/Epoxy), which has the same fibre architecture of a cross-ply [03/903]2s lay-up. The studies clearly reveal that the CF/PEEK composites exhibit the better impact performance. Also, at the same impact energy of 10.5 ± 0.3 J, the relatively high-velocity test at 54.4 ± 1.0 m s−1 leads to more damage in both types of composite than observed from the low-velocity test where the impactor struck the composites at 2.56 m s−1. The computationally efficient, two-dimensional, elastic, finite element model that has been developed is generally successful in capturing the essential details of the impact test and the impact damage in the composites, and has been used to predict the loading response of the composites under impact loading.

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Low-velocity dynamic compression tests were performed to reveal the failure mechanism and the energy absorption capacity of the integrated woven sandwich composite. Shear deformations were induced by the tilting of fiber piles in the core of the integrated woven sandwich composite. Ductile load–displacement curves are featured by a long deformation plateau originated from rotations of the core piles. Densification is apparent in the later stage of compression. Stout piles in the core also lead to plastic compression failure mode accompanying with much smaller rotations of core piles. Controlled by the latter failure mode, the dynamic strength and the energy absorption of the panel are stronger. In dynamic compression experiments, the integrated woven sandwich composite panels exhibit similar failure modes with those observed in quasi-static compression tests. The dynamic strength is much greater and the corresponding deformation plateau is much more stable, which leads to greater energy absorption. The dynamic effects of the strength and the energy absorption were explained by the dynamic buckling of the woven struts in the core. The tests suggest that the integrated woven sandwich composite is ideal to serve as a lightweight anti-impact material in engineering structures.