Electromagnetic Scattering by Open-Ended Cavities: An Analysis Using Precorrected-FFT Approach

In this paper, the precorrected-FFT method is used to solve the electromagnetic scattering from two-dimensional cavities of arbitrary shape. The integral equation is discretized by the method of moments and the resultant matrix equation is solved iteratively by the generalized conjugate residual method. Instead of directly computing the matrix-vector multiplication, which requires N² operations, this approach reduces the computation complexity to O(N log N) as well as avoids the storage of large matrices. At the same time, a technique known as the complexifying k is applied to accelerate the convergence of the iterative method in solving this resonance problem. Some examples are considered and excellent agreements of radar cross sections between these computed using the present method and those from the direct solution are observed, demonstrating the feasibility and efficiency of the present method.Singapore-MIT Alliance (SMA

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Research Progress of Urban Wind and Thermal Environment Based on CiteSpace and China National Knowledge Infrastructure Database

The urban wind–thermal environment affects the sustainable development of the urban ecological environment. In recent years, China has frequently suffered from storms, hurricanes, floods, and other disasters that damage the urban ecology. The urban wind and thermal environment involves many components; therefore, it is necessary to systematically review the current research progress in China. This paper uses CiteSpace software to analyze researchers, institutions, keywords, and research hotspots. By summarizing the knowledge structure, temporal and spatial distribution, evolution trends, and frontiers and hotspots of urban wind and thermal environment research, it is found that (1) the urban wind and thermal environment has gradually become a research hotspot in the field of the urban ecological environment; (2) the cooperative relationship between authors generally presents the characteristics of “large dispersion, small aggregation”, and the inter-institutional cooperation in this field is close and forms part of the interdisciplinary cooperation; (3) the research content involves a variety of disciplines and provides a good platform for interdisciplinary research, and the focus of the research has gradually shifted from the macro urban layout to the micro urban local environment; and (4) in order to obtain a more targeted understanding of the mechanisms of the urban wind–thermal environment, technical methods and regulatory means should be used to study the target at different scales and levels. In the future, multidisciplinary communication should be strengthened, qualitative and quantitative research should be performed with the help of mature technical methods in various disciplines, and the scale classification of research objects should be refined to improve the theoretical methods and evaluation system of each scale

Research Progress of Urban Wind and Thermal Environment Based on CiteSpace and China National Knowledge Infrastructure Database

The urban wind–thermal environment affects the sustainable development of the urban ecological environment. In recent years, China has frequently suffered from storms, hurricanes, floods, and other disasters that damage the urban ecology. The urban wind and thermal environment involves many components; therefore, it is necessary to systematically review the current research progress in China. This paper uses CiteSpace software to analyze researchers, institutions, keywords, and research hotspots. By summarizing the knowledge structure, temporal and spatial distribution, evolution trends, and frontiers and hotspots of urban wind and thermal environment research, it is found that (1) the urban wind and thermal environment has gradually become a research hotspot in the field of the urban ecological environment; (2) the cooperative relationship between authors generally presents the characteristics of “large dispersion, small aggregation”, and the inter-institutional cooperation in this field is close and forms part of the interdisciplinary cooperation; (3) the research content involves a variety of disciplines and provides a good platform for interdisciplinary research, and the focus of the research has gradually shifted from the macro urban layout to the micro urban local environment; and (4) in order to obtain a more targeted understanding of the mechanisms of the urban wind–thermal environment, technical methods and regulatory means should be used to study the target at different scales and levels. In the future, multidisciplinary communication should be strengthened, qualitative and quantitative research should be performed with the help of mature technical methods in various disciplines, and the scale classification of research objects should be refined to improve the theoretical methods and evaluation system of each scale

Analytical solution and optimal design for the output performance of Galfenol cantilever energy harvester considering electromechanical coupling effect

Abstract The theoretical model of a Galfenol cantilever energy harvester is investigated for vibration energy harvesting. Compared with the numerical solution, the analytical solution can better capture the intrinsic effects of the physical parameters on the performance of the harvester. In this work, an electromechanical coupled distributed-parameter model of the Galfenol cantilever energy harvester is established based on Hamilton’s principle, linear constitutive equations of magnetostrictive material, and Faraday’s law of electromagnetic induction. The definitions and expressions of the electric damping and modified frequency are proposed due to the electromechanical coupling. The explicit analytical expressions of the average harvested power across the load resistance and tip vibration displacement of the Galfenol energy harvesting model are derived using the methods of Galliakin decomposition and electromechanical decoupling. The accuracy of the derived analytical results is verified by the experimental data and numerical solutions. The vibration response and energy harvesting performance of the Galfenol energy harvesting model are investigated by varying the excitation frequency, external resistance, and excitation acceleration amplitude. The analytical results show that, with the increase of the external load resistance and excitation frequency, the harvested power increases first and then decreases, indicating the existence of the optimal resistance and excitation frequency. From the explicit analytical expressions of the average harvested power, the optimal external load resistance or excitation frequency could be easily found to achieve the maximum harvested power for any fixed excitation frequency or external load resistance. The concept of proposing the electric damping and modified frequency for the Galfenol cantilever energy harvester simplifies the solution process for the output performances benefiting from the exact relationship between the output performances and the electromechanical coupling parameter derived in this work

Effects of water content on the dissolution behavior of wool keratin using 1-ethyl-3-methylimidazolium dimethylphosphate

Ionic liquids (ILs) are eco-friend and recyclable solvents for dissolution of wool keratin, and water is often used as antisolvent to regenerate keratin from IL solution. To recycle the ILs, removing water is the necessary step. However, complete removal of the water is energy-intensive and costly. The water in ionic liquids would change the physicochemical properties and cluster structures of the IL and further affect its dissolution behavior on keratin. Here, 1-ethyl-3-methylimidazolium dimethylphosphate ([Emim]DMP) was used for experiments due to its good performance on dissolving keratin. The experimental and simulation results showed that the dissolving capability of [Emim]DMP was decreased and the interactions between cation and anion became weaker with water concentration increasing. Furthermore, the dissolution time of wool keratin in [Emim]DMP increased with water content rising. At the same time, the effect of water in ILs on the secondary structure distribution and thermal stability of regenerated keratin was not obvious. In this work, by taking the structures of [Emim]DMP, keratin dissolution time and properties of the regenerated keratin into consideration, a balanced range of water content in [Emim]DMP was determined, which could not only reduce recycling cost but also not affect the dissolution behavior of the IL.</p

effectsofwatercontentonthedissolutionbehaviorofwoolkeratinusinglethyl3methylimidazoliumdimethylphosphate

Ionic liquids (ILs) are eco-friend and recyclable solvents for dissolution of wool keratin,and water is often used as antisolvent to regenerate keratin from IL solution. To recycle the ILs,removing water is the necessary step. However,complete removal of the water is energy-intensive and costly. The water in ionic liquids would change the physicochemical properties and cluster structures of the IL and further affect its dissolution behavior on keratin. Here,1 -ethyl-3-methylimidazolium dimethylphosphate (EmimDMP) was used for experiments due to its good performance on dissolving keratin. The experimental and simulation results showed that the dissolving capability of EmimDMP was decreased and the interactions between cation and anion became weaker with water concentration increasing. Furthermore,the dissolution time of wool keratin in EmimDMP increased with water content rising. At the same time, the effect of water in ILs on the secondary structure distribution and thermal stability of regenerated keratin was not obvious. In this work,by taking the structures of EmimDMP,keratin dissolution time and properties of the regenerated keratin into consideration, a balanced range of water content in EmimDMP was determined, which could not only reduce recycling cost but also not affect the dissolution behavior of the IL