Recovered Energy from Salinity Gradients Utilizing Various Poly(Acrylic Acid)-Based Hydrogels

Hydrogels can be utilized to extract energy from salinity gradients when river water mixes with seawater. Saline-sensitive hydrogels exhibit a reversible swelling/shrinking process when they are, alternately, exposed to fresh and saline water. We present a comparison of several poly(acrylic acid)-based hydrogels, including poly(acrylic acid) (PAA), poly(acrylic acid-co-vinylsulfonic acid) (PAA/PVSA), and poly(4-styrenessulfonic acid-co-maleic acid) interpenetrated in a poly(acrylic acid) network (PAA/PSSA-MA). The hydrogels were synthesized by free radical polymerization, copolymerization, and by semi-IPN (interpenetrating polymer network). The hydrogels were placed in a piston-like system to measure the recovered energy. Semi-IPN hydrogels exhibit a much higher recovered energy compared to the copolymer and PAA hydrogel. The recovered energy of 60 g swollen gel was up to 4 J for the PAA/PSSA-MA hydrogel. The obtained energy per gram dried gel was up to 13.3 J/g. The swelling volume of the hydrogels was maintained for 30 cycles without decline in recovered energy.publishedVersio

THE INFRASTRUCTURE AND ENVIRONMENT IN THE OLD TENEMENTS IN HANOI

Joint Research on Environmental Science and Technology for the Eart

Thermal analysis of multi-layer walls containing geopolymer concrete and phase change materials for building applications

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Energy Lost in a Hydrogel Osmotic Engine Due to a Pressure Drop

Utilizing hydrogels to harvest salinity gradient energy from solutions of different salinities has recently attracted interest. Polyelectrolyte hydrogels exhibit cyclic swelling/deswelling when alternately exposed to freshwater and seawater. This can be utilized to convert the mixing energy of the two solutions into mechanical energy. Hydrogels consisting of a semi-interpenetrating network (semi-IPN) of poly(4-styrene sulfonic acid-co-maleic acid) sodium salt and polyacrylic acid was prepared at various cross-linking densities. The energy lost due to a pressure drop in the system during the deswelling/swelling process of these hydrogels is examined, and the effects of tubing dimensions, hydrogel cylinder size, gel particle size, and the volume fraction within the hydrogel cylinder occupied by the flowing liquid (ε) are investigated. In addition, a small-scale osmotic engine was compared to a scaled-up system. ε was found to be the factor that had the largest effect on the energy loss. It was found that ε is strongly dependent on the degree of swelling of the hydrogels. When the hydrogels swell, they deform more easily under pressure. This markedly decreases ε, thereby inducing a high pressure drop in the system and a correspondingly large energy loss. Accordingly, the pressure drop when pumping through the hydrogel is the major contributor to the energy loss in the system. When the hydrogel particles deform too much, the energy needed to pump the flowing liquid through the hydrogels exceeds the energy produced by the system. Developing a hydrogel system that deforms less in its swollen state is therefore essential for improving the energy efficiencies of these osmotic engines.publishedVersio

Osmotic engine converting energy from salinity difference to a hydraulic accumulator by utilizing polyelectrolyte hydrogels

Efficient harvesting of the mixing energy from the salinity gradient between sea and river water remains a challenge. Recently, utilization of the swelling/shrinking properties of hydrogels has been explored as a new means for extracting this energy. However, former investigations are mainly limited to examining the performance of the hydrogels when lifting applied weights, and calculating the energy that could potentially be extracted. In this study, we demonstrate a novel osmotic engine with a mechanical energy transmission prototype, which can convert and store the green mixing energy in a form that can be utilized to perform mechanical work. The osmotic engine includes a cylinder containing the hydrogel, an oil-hydraulic cylinder and a hydraulic accumulator. The lifting energy from the hydrogel is transferred to the oil-hydraulic cylinder through a lever, which acts as a pump and accumulate the hydraulic oil under high pressure in the hydraulic accumulator. The system was tested with a hydrogel of poly(acrylic acid) semi-interpenetrated with poly(4-styrenessulfonic acid-co-maleic acid) sodium. This hydrogel produced up to 36 J per shrinking/swelling cycle, and exhibited an efficiency of 0.53% at optimum conditions.publishedVersio

Salinity Gradient Energy from Expansion and Contraction of Poly(allylamine hydrochloride) Hydrogels

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Thermal analysis of geopolymer concrete walls containing microencapsulated phase change materials for building applications

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Thermal performance and numerical simulation of geopolymer concrete containing different types of thermoregulating materials for passive building applications.

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Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

Emerging the real‐time performance for the single axis slave controller in the decentralised network

Abstract In the era of the fourth industrial revolution, many certain technologies such as Internet of Things (IoT) or Internet of Service (IoS) have been implemented for the improvement of current system. However, most of them did not ensure the real‐time performance which is inevitable for modern motion systems. The implementation of Ethernet‐based protocol, rapid data exchange and synchronised transmission are proper for the novelties of slave controller. An integration of the decentralised network into the motion control system is introduced firstly. To demonstrate the conceptual design, some descriptions of motivations and related definitions are explained. Then, the structure of hardware components and internal connections are mentioned. Later, the software architecture including the data exchange and flowchart of motion program, is described in detail. To verify the feasibility and effectiveness of the proposed approach, some technical analysis of timing synchronisation and tracking deviation between our method and the others are carried out. In addition, several practical validations are conducted in the same conditions. The contributions of the authors are (i) to firstly present the concept of controller design using the real‐time technology, (ii) to illuminate both hardware design and software design of the proposed approach and (iii) to analyse the superior performance in delay time between our method and the others as well as validate the real‐world results to prove the effectiveness and feasibility. From the authors’ achievement, it is observed that these results can be broadly purposeful to the sustainable development of Industry 4.0