Nonlinear dynamic modeling of ionic polymer conductive network composite actuators using rigid finite element method

Ionic polymer conductive network composite (IPCNC) actuators are a class of electroactive polymer composites that exhibit some interesting electromechanical characteristics such as low voltage actuation, large displacements, and benefit from low density and elastic modulus. Thus, these emerging materials have potential applications in biomimetic and biomedical devices. Whereas significant efforts have been directed toward the development of IPMC actuators, the establishment of a proper mathematical model that could effectively predict the actuators' dynamic behavior is still a key challenge. This paper presents development of an effective modeling strategy for dynamic analysis of IPCNC actuators undergoing large bending deformations. The proposed model is composed of two parts, namely electrical and mechanical dynamic models. The electrical model describes the actuator as a resistive-capacitive (RC) transmission line, whereas the mechanical model describes the actuator as a system of rigid links connected by spring-damping elements. The proposed modeling approach is validated by experimental data, and the results are discussed. © 2014 Elsevier B.V. All rights reserved.

Self-assembled multimicellar vesicles via complexation of a rigid conjugated polymer with an amphiphilic block copolymer

A viable method of encapsulating block copolymer micelles inside vesicles using a conjugated polymer is reported in this study. Self-assembly and complexation between an amphiphilic block copolymer poly(methyl methacrylate)-b-poly(acrylic acid) (PMMA-b-PAA) and a rod-like conjugated polymer polyaniline (PANI) in aqueous solution were studied using transmission electron microscopy, atomic force microscopy and dynamic light scattering. The complexation and morphology transformation were driven by electrostatic interaction between PANI and the PAA block of the block copolymer. Addition of PANI to PMMA-b-PAA induced the morphology transformation from micelles to irregular vesicles through vesicles, thick-walled vesicles (TWVs) and multimicellar vesicles (MMVs). Among the observed morphologies, MMVs were observed for the first time. Morphology transformation was studied as a function of aniline/acrylic acid molar ratio ([ANI]/[AA]). Micelles were observed for the pure block copolymer, while vesicles and TWVs were observed at [ANI]/[AA] = 0.1 and 0.3, respectively. MMVs were observed at [ANI]/[AA] = 0.5 and irregular vesicles were observed for molar ratios at 0.7 and above. Clearly, a conjugated polymer like polyaniline can induce a morphology transformation even at its lower concentrations and produce complex morphologies.

Large compound vesicles from amphiphilic block copolymer/rigid-rod conjugated polymer complexes

Morphology evolution in complexes of amphiphilic block copolymers poly(styrene)-b-poly(acrylic acid) (PS-b-PAA) and poly(styrene)-b-poly(ethylene oxide) (PS-b-PEO) in the presence of polyaniline (PANI) in aqueous solution is reported. Transmission electron microscopy, atomic force microscopy, and dynamic light scattering techniques were used to study the morphologies at various PANI contents [aniline]/[acrylic acid] ([ANI]/[AA]) ranging from 0.1 to 0.7. The interpolyelectrolyte complex formed between PAA and PANI plays a key role in the morphology transformation. Spherical micelles formed from pure block copolymers were transformed into large compound vesicles upon increasing PANI concentration due to internal block copolymer segregation. In addition to varying PANI content, the kinetic pathway of nanoparticle formation was controlled through different water addition methods and was critical in the formation of multigeometry nanoparticles.

Efficient and accurate set-based registration of time-separated aerial images

This paper addresses the task of time-separated aerial image registration. The ability to solve this problem accurately and reliably is important for a variety of subsequent image understanding applications. The principal challenge lies in the extent and nature of transient appearance variation that a land area can undergo, such as that caused by the change under illumination conditions, seasonal variations, or the occlusion by non-persistent objects (people, cars). Our work introduces several major novelties (i) unlike previous work on aerial image registration, we approach the problem using a set-based paradigm; (ii) we show how image space local, pair-wise constraints can be used to enforce a globally good registration using a constraints graph structure; (iii) we show how a simple holistic representation derived from raw aerial images can be used as a basic building block of the constraints graph in a manner which achieves both high registration accuracy and speed; (iv) lastly, we introduce a new and, to the best of our knowledge, the only data corpus suitable for the evaluation of set-based aerial image registration algorithms. Using this data set, we demonstrate (i) that the proposed method outperforms the state-of-the-art for pair-wise registration already, achieving greater accuracy and reliability, while at the same time reducing the computational cost of the task and (ii) that the increase in the number of available images in a set consistently reduces the average registration error, with a major difference already for a single additional image.

Evaluating a standardised clinical assessment tool for pre-registration midwifery students: a cross-sectional survey of midwifery students and midwives in Australia

Abstract
Background: Assessment of clinical competence is a core component of midwifery education. Clinical assessment tools have been developed to help increase consistency and overcome subjectivity of assessment.
Aim: The study had two main aims. The first was to explore midwifery students and educators/clinical midwives’ views and experiences of a common clinical assessment tool used for all preregistration midwifery programmes in Victoria and the University of South Australia. The Second was to assess the need for changes to the tool to align with developments in clinical practice and evidence-based care.
Methods: A cross-sectional, web-based survey including Likert-type scales and open-ended questions was utilised.
Setting: Students enrolled in all four entry pathways to midwifery at seven Victorian and one South Australian University and educators/clinical midwives across both states.
Findings: One hundred and ninety-one midwifery students’ and 86 educators/clinical midwives responded.
Overall, students and educators/clinical midwives were positive about the Clinical Assessment Tool with over 90% reporting that it covered the necessary midwifery skills. Students and educators/clinical midwives reported high levels of satisfaction with the content of the learning tools. Only 4% of educators/clinical midwives and 6% of students rated the Clinical Assessment Tool as poor overall. Changes to some learning tools were necessary in order to reflect recent practice and evidence.
Key conclusions and implications for practice: A common clinical assessment tool for evaluating midwifery students’ clinical practice may facilitate the provision of consistent, reliable and objective assessment of student skills and competency.

Groupwise registration of aerial images

This paper addresses the task of time separated aerial image registration. The ability to solve this problem accurately and reliably is important for a variety of subsequent image understanding applications. The principal challenge lies in the extent and nature of transient appearance variation that a land area can undergo, such as that caused by the change in illumination conditions, seasonal variations, or the occlusion by non-persistent objects (people, cars). Our work introduces several novelties: (i) unlike all previous work on aerial image registration, we approach the problem using a set-based paradigm; (ii) we show how local, pairwise constraints can be used to enforce a globally good registration using a constraints graph structure; (iii) we show how a simple holistic representation derived from raw aerial images can be used as a basic building block of the constraints graph in a manner which achieves both high registration accuracy and speed. We demonstrate: (i) that the proposed method outperforms the state-of-the-art for pair-wise registration already, achieving greater accuracy and reliability, while at the same time reducing the computational cost of the task; and (ii) that the increase in the number of available images in a set consistently reduces the average registration error.

Rigid removable cover for dorsal wound protection and tube fixation in pigs

Objective To report the design and benefits of a rigid polyethylenecover ‘shell’ for the protection of dorsal torso wounds andtube fixation in pigs.

Methods Open C-shaped polyethylene shells were designed toprotect wounds and dressings on the dorsum of pigs used inresearch into negative pressure dressing-assisted wound healing.The shells were designed to resist trauma and contamination, tobe comfortable and expansible, and to facilitate tube fixation andmanagement. Strap fixation was optimised during experimentation. Efficacy was assessed by direct observation of dressing andwound protection, tube integrity and by macroscopic and microscopicassessments of wound healing.

Results The shells effectively protected the wounds againstblunt and sharp trauma, were simple to remove and reapply, were well tolerated and allowed for growth of the pigs. Circumferentia lneck straps attached by lateral straps to the shells provedcritical. There was no wound infection or inflammation underlyingthe shells. Porting tubing via mid-dorsal holes in the shells andaffixing the tubing just cranial to these holes prevented tubedamage and traction, permitted tube management from outsidethe cages and allowed the pigs to move freely without becomingentangled.

Conclusion These shells effectively protected dorsal skinwounds and dressings, prevented tube damage and facilitatedtube management in pigs. Similar systems may be useful forother production animals for wound management and for tubemanagement with negative pressure wound healing, drain tubesor the delivery of nutrition, fluids or medications.

Flexible and rigid amine-functionalized microporous frameworks based on different secondary building units: supramolecular isomerism, selective CO₂ capture, and catalysis

We report the synthesis, structural characterization, and porous properties of two isomeric supramolecular complexes of ([Cd(NH₂—bdc)(bphz)_0.5 ]⋅DMF⋅H₂O}_n (NH₂ —bdc=2-aminobenzenedicarboxylic acid, bphz=1,2-bis(4-pyridylmethylene)hydrazine) composed of a mixed-ligand system. The first isomer, with a paddle-wheel-type Cd₂ (COO)₄ secondary building unit (SBU), is flexible in nature, whereas the other isomer has a rigid framework based on a μ-oxo-bridged Cd₂(μ-OCO)₂ SBU. Both frameworks are two-fold interpenetrated and the pore surface is decorated with pendant -NH₂ and =N—N= functional groups. Both the frameworks are nonporous to N₂ , revealed by the type II adsorption profiles. However, at 195 K, the first isomer shows an unusual double-step hysteretic CO₂ adsorption profile, whereas the second isomer shows a typical type I CO₂ profile. Moreover, at 195 K, both frameworks show excellent selectivity for CO₂ among other gases (N₂ , O₂ , H₂ , and Ar), which has been correlated to the specific interaction of CO₂ with the -NH₂ and =N—N= functionalized pore surface. DFT calculations for the oxo-bridged isomer unveiled that the -NH₂ group is the primary binding site for CO₂ . The high heat of CO₂ adsorption (ΔH_ads =37.7 kJ mol^-1) in the oxo-bridged isomer is realized by NH₂ ⋅⋅⋅CO₂ /aromatic π⋅⋅⋅CO₂ and cooperative CO₂ ⋅⋅⋅CO₂ interactions. Further, postsynthetic modification of the -NH₂ group into -NHCOCH₃ in the second isomer leads to a reduced CO₂ uptake with lower binding energy, which establishes the critical role of the -NH₂ group for CO₂ capture. The presence of basic -NH₂ sites in the oxo-bridged isomer was further exploited for efficient catalytic activity in a Knoevenagel condensation reaction.

Investigating the use of IELTS in determining employment, migration and professional registration outcomes in healthcare and early chidlhood education in Australia

Focusing on two professional fields that are critical to Australia’s future – health and early childhood education – the study provides key insights into the many challenges facing overseas-trained professionals and international graduates transitioning into the Australian labour market.The study highlights the complex language requirements in the professions of medicine, nursing and early childhood education and explores the implications for stakeholders. Employers require graduates to have high-level English language skills, and universities are increasingly expected to ensure international students graduate with the required English language proficiency.Finally, the study highlights the many challenges facing overseas-trained/international graduates transitioning into the labour market. For participants in this study, the challenges of working in their profession in Australia are many and varied. These challenges include workplace discrimination, isolation and extreme frustration when unable to work in their area of qualification.