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In this paper, impedance modeling of a DC microgrid system consisting of a source and load converter, including an input filter, is performed. Impedance-based modeling has been used to derive mathematical models of the output impedance of the source converter and the input impedance of the load converter. The correlation between the converter interaction and system stability is analyzed based on the mathematical model. An impedance-based stability analysis is used to determine the system stability by analyzing the interactions among the converters in the DC microgrid system. Middlebrook's stability criterion, which uses the impedance transfer function, is applied to determine system stability. Moreover, in this paper, a stability enhancement control algorithm is proposed to resolve the system instabilities resulting from interaction among the converters and the distortion caused by the harmonics emanating from the AC input. The proposed stability enhancement control algorithm consists of a feed-forward type virtual impedance (VI) and a proportional-resonant (PR) controller. The validity of the proposed method is demonstrated by the results of the response characteristics in the frequency domain, and the effectiveness of the proposed control algorithm is verified via simulations and prototype experimental models.

Background. Bacteremia is a major nosocomial infection that frequently occurs in trauma patients, increasing morbidity and mortality. The aim of this study was to identify risk factors and to describe epidemiological patterns for early onset (EOB) and late onset (LOB) bacteremia after trauma. Methods. We retrospectively reviewed medical records of all trauma patients admitted to the surgical intensive care unit and general ward between January 2011 and December 2015. The information was collected for each patient and recorded in a computer database: early onset bacteremia (EOB) was defined as when onset occurred within 7 days after trauma, and late onset bacteremia (LOB) was defined as when onset occurred after 7 days from trauma. Results. Thirty-four patients of 859 (4%) developed bacteremia during their hospital stay: 4 (11.8%) developed EOB, 26 (76.4%) LOB, and 4 (11.8%) patients developed both of them. Sixty events of bacteremia happened to these patients: 9 (15.0%) EOB and 51 (85.0%) LOB. Gram-positive cocci were isolated more frequently than Gram-negative bacilli in both groups. Gram-positive cocci were more frequently isolated in EOB than in LOB; otherwise, there was no statistical significance (77.8% vs. 64.7%, p=0.683). Central line-associated blood stream infection (CLABSI) and surgical site infection (SSI) were the most common identified source for LOB. Presence of liver (OR: 2.66, p=0.035) and pelvic injury (OR: 2.25, p=0.038), gastrointestinal tract perforation (OR: 5.48, p=0.002), and massive transfusion (OR: 3.36, p=0.006) represented risk factors for bacteremia. Conclusions. Presence of pelvic and liver injury on arrival in emergency department, gastrointestinal tract perforation, and massive transfusion within the first 24 hours after trauma appears to be significant risk factors for bacteremia.

Crystalline polymers with functionalities along the backbone can store and transfer electrons, ions and gases and thus can be used in devices. However, the formation of such materials can be difficult. Here, Lee and others have produced highly crystalline conjugated polymers via two-monomer-connected precursors.

A study is conducted to compare investigation of energy relaxation dynamics of gold nanoparticles and gold-polypyrrole encapsulated nanoparticles. The results indicate that directly attached polypyrroles provide fast thermal energy transfer pathways for the core gold nanoparticles.

The light emission decay in bare gold particles by using the fluorescence up-conversion technique is reported. The results indicate that a weak light emission from relatively large gold nanoparticles is attributable to the interactions between surface plasmons and incident photons that occur simultaneously with the thermal electron relaxation.

The tethering rodlike polymers on the solid surfaces by their chain ends with a moderate grafting density can easily lead to the development liquid crystalline monolayer of planar-oriented rods. The described approach can hence be used for the designing of various well-ordered monolayers of rodlike polymers with various functionalities.

The identification of sodium benzanilide (Na-BA) as a very efficient initiator for the polymerization of a highly reactive monomer n-hexyl isocyanate is discussed. Na-BA has a very slow initiation rate with the additive function of chain-end protection eliminating the need for another additive, offering in the process a perfect control over molecular weight and molecular weight distribution.

This paper presents a torque error compensation algorithm for a surface mounted permanent magnet synchronous machine (SPMSM) through real time permanent magnet (PM) flux linkage estimation at various temperature conditions from medium to rated speed. As known, the PM flux linkage in SPMSMs varies with the thermal conditions. Since a maximum torque per ampere look up table, a control method used for copper loss minimization, is developed based on estimated PM flux linkage, variation of PM flux linkage results in undesired torque development of SPMSM drives. In this paper, PM flux linkage is estimated through a stator flux linkage observer and the torque error is compensated in real time using the estimated PM flux linkage. In this paper, the proposed torque error compensation algorithm is verified in simulation and experiment. [ABSTRACT FROM AUTHOR]

BACKGROUND: Devices gauging viscoelastic properties of blood during coagulation like the thromboelastograph support fundamental research as well as point of care needs. Associated fibrinolysis data are based on endogenous species or plasminogen activator added to a homogeneous sample prior to clot formation. Digestion in a monolithic structure differs from the physical situation of thrombolytic therapy where surface reactions dominate. OBJECTIVE: This study aims to develop rheological testing for heterogeneous phase fibrinolysis. METHOD: Fibrinolysis rates were determined by phase change of a solid clot induced by autologous plasma/streptokinase (SK) in a rheometer sensitive to viscous damping. RESULTS: Initial slope or overall change in the logarithmic damping factor indicated fibrinolytic rates. Rates depended on clot geometry, phase volumes, clot composition and SK concentration. CONCLUSION: The damped oscillation rheometer can be adapted to determine relative rates of heterogeneous fibrinolysis in vitro. [ABSTRACT FROM AUTHOR]

While acute treatment with beetroot juice (BRJ) containing nitrate (NO3-) can lower systolic blood pressure (SBP), afterload, and myocardial O2 demand during submaximal exercise, effects of chronic supplementation with BRJ (containing a relatively low dose of NO3-, 400 mg) on cardiac output (CO), SBP, total peripheral resistance (TPR), and the work of the heart in response to dynamic exercise are not known. Thus, in 14 healthy males (22 ± 1 yr), we compared effects of 15 days of both BRJ and nitrate-depleted beetroot juice (NDBRJ) supplementation on plasma concentrations of NOx (NO3-/NO2-), SBP, diastolic blood pressure (DBP), mean arterial pressure (MAP), CO, TPR, and rate pressure product (RPP) at rest and during progressive cycling exercise. Endothelial function was also assessed via flow-mediated dilation (FMD). BRJ supplementation increased plasma NOx from 83.8 ± 13.8 to 167.6 ± 13.2 μM. Compared with NDBRJ, BRJ reduced SBP, DBP, MAP, and TPR at rest and during exercise (P < 0.05). In addition, RPP was decreased during exercise, while CO was increased, but only at rest and the 30% workload (P < 0.05). BRJ enhanced FMD-induced increases in brachial artery diameter (pre: 12.3 ± 1.6%; post: 17.8 ± 1.9%). We conclude that 1) chronic supplementation with BRJ lowers blood pressure and vascular resistance at rest and during exercise and attenuates RPP during exercise and 2) these effects may be due, in part, to enhanced endothelium-induced vasodilation in contracting skeletal muscle. Findings suggest that BRJ can act as a dietary nutraceutical capable of enhancing O2 delivery and reducing work of the heart, such that exercise can be performed at a given workload for a longer period of time before the onset of fatigue. [ABSTRACT FROM AUTHOR]

Most of controlling disaster managements focus on how to rescue people from disaster areas. In this paper, we propose an emergency escape system that helps people escape by themselves effectively from a disaster area in which each person owns a mobile device. We define a scenario for the proposed system in which there are five system states; they are Idle, Discovery, Subscription/Publication, Execution, and Communication states. The system uses several technologies such as service-oriented architecture, GPS and Wi-Fi positioning systems, and some sensors. The proposed system utilizes users' information such as weighted distances, weighted directions and revisit counts. The system is implemented on a double-layered MANET to reduce traffic and to collaborate with each other. We have constructed a simulator to test the proposed system. The simulation results show that the proposed system outperforms other approaches in terms of the distance and the time proving that the proposed system could be an effective life-saving rescue system. [ABSTRACT FROM AUTHOR]

Side chain crosslinked (C-SFPEx-CMy) sulfonated poly(arylene ether) (SPAE) membranes containing fluorine moiety with varying degree of sulfonation (DS) were prepared and evaluated for use as a thin-film composite membrane for seawater desalination. C-SFPEx-CMy membranes were obtained by covalent crosslinking among ethynyl groups at the polymer side chain through thermal curing. The crosslinked network structure suppressed the water uptake and swelling ratio. A novel type of composite membranes (TC-SFPEx-CMy) were prepared side chain crosslinked SPAE layer containing fluorine moiety on top of PET non-woven with epoxy resin as bonding agent. TC-SFPEx-CMy show the increase in NaCl rejection as DS decreases from 30% to 70%. NaCl rejection of the membranes increased with increasing corsslinking moiety (CM) while water permeability decreases due to the crosslinked net work structure. Particularly, crosslinked membrane of 30 mol % of CM could enhance the salt (NaCl) rejection property up to 85.3 % as compared to of crosslinked membrane (69.5%) containing 10 mol % of CM under same DS. However crosslinked membrane showed the decrease in water permeability from 6.89 L/m²-h (TC-SFPE30-CM10) to 2.06 L/m2-h (TC-SFPE30-CM30). For TC-SFPE30-CM30 membrane, the order of salt rejection was observed Na2SO4 > NaCl > MgSO4 > MgCL2 [ABSTRACT FROM AUTHOR]

A novel composite membrane for potential desalination was prepared by coating of sulfonated poly(arylene ether) on the non-woven web. The non-woven web was made of end-group cross-linkable flurorinated poly(arylene ether) nanowires fabricated by electrospinning method. The crosslinked non-woven web was obtained by covalent crosslinking among ethynyl groups at the polymer chain end via thermal curing. The salt rejection and permeability of the crosslinked non-woven web were controlled by varying degrees of sulfonation (DS) of sulfonated poly(arylene ether). The compostie membranes show the increase of NaCl rejection as DS decreases from 20% to 60%, while water permeability decreases due to the increase of hydrophilicity. The order of salt rejection was as follows: Na2SO4 (88.4%), NaCl (79.3%), MgSO4 (70.2%), Mg2Cl2 (62.3%). [ABSTRACT FROM AUTHOR]

SiO2mesoporous materials were prepared by decomposition of a polymer matrix from nanocomposites that were incorporated with a SiO2sol. Polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) was synthesized using living anionic polymerization and the P2VP block was quaternized for a matrix of nanoparticles. The SiO2sol was selectively embedded into the quaternized P2VP domain of PS-b-P2VP diblock copolymer with a sphere or lamella morphology. Then the polymers were etched out by heating. The phase separation of the block copolymers and the SiO2incorporated nanocomposites was observed by EF-TEM. The controlled mesoporous morphologies were obtained according to the block ratio of block copolymers. [ABSTRACT FROM AUTHOR]