115 research outputs found

    Influence of Water Quality on the Efficiency of Retention Aids Systems for the Paper Industry

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    It has been reported that about 10-15% of the fresh water intake in a paper mill is used for feeding and diluting retention aids, so significant savings could be achieved by replacing fresh water with process water. Water from different sources and qualitiessfresh water, the outflow from an internal ultrafiltration placed in the machine circuit of a paper mill, and water from a membrane bioreactor used to treat the final effluent of this paper millswere used to prepare a dual retention system consisting of a cationic polyacrylamide and bentonite. While the behavior of bentonite was not significantly affected by the quality of the water used in its preparation, the efficiency of the cationic polyacrylamide was reduced to about 12% when it was prepared with water with high anionic trash content and conductivity as a result of a partial neutralization of the charged groups. The effect of nonionic chemical oxygen demand on the efficiency of the polymer was negligible

    Smart meters in smart manufacturing

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    The extent of change in business process and smart manufacturing usage should be taken into account in every energy efficiency project in industries. A significant part of smart metering success depends upon making the business processes more systematic. Smart manufacturing in the dramatically intensified and pervasive application of networked information-based technologies through the manufacturing and supply chain enterprise. There is no doubt that the deployment os smart meters involves complex and different business models, the management of significant risks, and the need for research and developtment of new technologies, business models and organization engineering. Industrial energy audits play an important role in achieving cost optimization and peak load reduction goals for industry. In this paper, we present the impact of smart meters in industry. In essence, smart meters promotes the (r)evolution of smart manufacturing

    Identifying engagement and associated factors in nursing students: An exploratory study

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    Background Burnout and engagement in health students surpass work life. Although levels of burnout in Nursing students are high, academic engagement is an understudied topic in Nursing, which has shown benefits. The aims were to know the level of engagement of Nursing students and to identify factors that prompt higher levels of engagement. Methods An exploratory study was conducted during 2019 in three Universities in Spain. The UWES-S-17 questionnaire was used. Results The sample consisted of 808 Nursing students. An average level of engagement was found. Engagement differed significantly by gender and age, with females and older students showing greater attitudes. Participants in the second year showed lower scores in the willingness to dedicate effort and persistence than those in the first and third year (p < 0.05). Conclusions The identification of the level of engagement and factors involved are an opportunity to probe into this approach by reinforcing positive attitudes in Nursing students. These findings show the need to seek strategies through specific educational interventions and policies. Engagement should be upheld throughout the degree and once they enter the job market to ensure the well-being during academic and future work life, a high-quality nursing care and patient safetyS

    Gain-Reconfigurable Hybrid Metal-Graphene Printed Yagi Antenna for Energy Harvesting Applications

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    This paper presents a hybrid metal-graphene printed Yagi antenna with reconfigurable gain that operates in the 5.5-GHz band. The balun and the driven elements are made of copper, while the directors are made of graphene. The graphene acts as a tunable material in the design. By switching the conductivity of the graphene, it is achieved a similar effect to adding or subtracting directors in the antenna. Hence the gain of the printed Yagi can be easily controlled. This could be of special interest in RF energy harvesting in the design of reconfigurable harvesting elements.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    pH and particle structure effects on silica removal by coagulation

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    Producción CientíficaCoagulation is presented as an efficient alternative to reduce the silica content in effluents from recovered-paper mills that are intended to be recycled by a final reverse-osmosis (RO) step. Coagulation pretreatment by several polyaluminum chlorides (PACls) or FeCl3 was optimized prior to the RO process. PACls with low alumina content and high basicity achieved almost a 100 % removal of silica at pH 10.5. A good reduction of the silica content was attained without regulating the pH by adding one of these PACls. Silica removal was related to the structure of the produced clots in which cylindrical particles produced higher silica removal. All coagulants removed more than 50 % of the chemical oxygen demand (COD).Comunidad Autónoma de Madrid - (Proyecto P2009/AMB-1480)Ministerio de Ciencia e Innovación - (Proyecto CTM2008-06886-C02- 01)Comisión Europea - (Proyecto 211534

    Recycled Fibers for Sustainable Hybrid Fiber Cement Based Material: A Review

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    Reinforcing fibers have been widely used to improve physical and mechanical properties of cement-based materials. Most fiber reinforced composites (FRC) involve the use of a single type of fiber to improve cement properties, such as strength or ductility. To additionally improve other parameters, hybridization is required. Another key challenge, in the construction industry, is the implementation of green and sustainable strategies based on reducing raw materials consumption, designing novel structures with enhanced properties and low weight, and developing low environmental impact processes. Different recycled fibers have been used as raw materials to promote circular economy processes and new business opportunities in the cement-based sector. The valuable use of recycled fibers in hybrid FRC has already been proven and they improve both product quality and sustainability, but the generated knowledge is fragmented. This is the first review analyzing the use of recycled fibers in hybrid FRC and the hybridization effect on mechanical properties and workability of FRC. The paper compiles the best results and the optimal combinations of recycled fibers for hybrid FRC to identify key insights and gaps that may define future research to open new application fields for recycled hybrid FRC.TRUEComunidad de Madridpu

    Care tasks and impact of caring in primary family caregivers: a cross-sectional study from a nursing perspective

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    Family caregivers of persons with dementia often experience a negative impact on their health. More studies based on nursing theories are needed to improve the provision of careS

    Nanocelluloses: Natural-Based Materials for Fiber-Reinforced Cement Composites. A Critical Review

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    Nanocelluloses (NCs) are bio-based nano-structurated products that open up new solutions for natural material sciences. Although a high number of papers have described their production, properties, and potential applications in multiple industrial sectors, no review to date has focused on their possible use in cementitious composites, which is the aim of this review. It describes how they could be applied in the manufacturing process as a raw material or an additive. NCs improve mechanical properties (internal bonding strength, modulus of elasticity (MOE), and modulus of rupture (MOR)), alter the rheology of the cement paste, and affect the physical properties of cements/cementitious composites. Additionally, the interactions between NCs and the other components of the fiber cement matrix are analyzed. The final result depends on many factors, such as the NC type, the dosage addition mode, the dispersion, the matrix type, and the curing process. However, all of these factors have not been studied in full so far. This review has also identified a number of unexplored areas of great potential for future research in relation to NC applications for fiber-reinforced cement composites, which will include their use as a surface treatment agent, an anionic flocculant, or an additive for wastewater treatment. Although NCs remain expensive, the market perspective is very promising

    Gender impact of caring on the health of caregivers of persons with dementia

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    Background: Dementia is a brain syndrome that affects a growing number of persons worldwide and generates a strong and progressive demand for care from a family caregiver, usually females. Objective: We aimed to describe the care provided by family caregivers of persons with dementia as well as the impact on their health and its interrelation with gender Patient involvement. This study was carried out in collaboration with the 13 associations of family caregivers of persons with dementia that are part of a Regional Federation. This partnership worked towards bettering patient care and proposing improvements to the public health system. Methods: A multi-institutional cross-sectional study. A total of 462 primary family caregivers of persons with dementia from north-west Spain were included. Data were collected between January and April 2019 with an anonymous self-administered validated questionnaire (ICUB-97) based on Virginia Henderson’s nursing care model. Results: The most affected needs in family caregivers are those related to “recreational activities”, “communication” and “rest and sleep”. Statistically significant differences between male and female participants’ pattern of care and health-related impacts were found, especially in issues related to work and family reconciliation. Discussion: Care plans should be developed taking gender perspective into account. From a nurse model point of view, more research is necessary to reduce health disparities. This study provides an assessment of gender differences in care and the impact on caregivers’ health. Practical value: Regarding the specific health conditions of female caregivers and from a holistic point of view, these findings could provide novel and interesting data that might help to implement gender perspective in nursing care plans, generally invisible in routine clinical practiceS
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