Electromagnetic interference shielding performance of carbon nanostructure reinforced, 3D printed polymer composites

Journal of Materials Science - We report the electrical, mechanical and electromagnetic interference (EMI) shielding performance of polypropylene random copolymer (PPR)/multi-wall carbon nanotube...     

Heparin‐induced thrombocytopenia in a hemodialysis patient treated with fondaparinux: Nephrologists between two fires

Heparin‐induced thrombocytopenia (HIT) is caused by heparin exposure and presents with reduced platelet count. Patients undergoing hemodialysis (HD) treatment have increased risk of developing HIT due to prolonged exposure to unfractionated heparin or low‐molecular weight heparin. We report a 79‐year‐old male patient with end‐stage renal disease who developed type‐II HIT during maintenance HD. Platelet count of the patient decreased gradually and antiplatelet factor IV antibody was found to be positive. The patient was treated with fondaparinux and continued heparin‐free HD. Unfortunately, despite favorable initial response without any thrombotic episodes, the patient died due to severe sepsis complicated by gastrointestinal hemorrhage.     

The effects of heat treatment on some technological properties in Uludağ fir (Abies bornmuellerinana Mattf.) wood

Heat treatment is often applied to improve the dimensional stability of woods. In this study, the effect of heat treatment on some mechanical properties of Uluda? fir wood (Abies bornmuellerinana Mattf.) having industrially high usage potential and large plantations in Turkey was evaluated. Samples collected from Bolu Forest Enterprises, Turkey were subjected to heat treatment for varying temperatures and durations. Then, the treated and control samples were tested for some mechanical properties; compression strength, bending strength, modulus of elasticity in bending, janka-hardness, impact bending strength and tension strength perpendicular to grain. The results indicated that treated samples had lower mechanical properties compared to the control samples. In addition, increase in temperature and durations decreased the mechanical properties.     

Response surface methodological study on HMF and fluorescent accumulation in red and white grape juices and concentrates

White and red grape juices and their concentrates were subjected to thermal treatments at different temperatures ranging from 50 to 70 °C at different times. 5-Hydroxymethylfurfural (5-HMF) and fluorescence relative index (FLRI) were measured. Response surface methodology (RSM) was applied to determine the effect of temperature and time on the HMF and FLRI formation at the different Brix (bx) degrees. An increase in temperature (from 50 to 70 °C) and time (from 12 to 192 h) for 15°, 45° and 65° Brix degrees was associated with an increase in HMF and FLRI development of white and red grape juices. HMF formation was higher in white grape juice and concentrates than in red ones. Optimum conditions were confirmed and these fitted the experimental data well. Thus, regression equations can be used to estimate HMF and FLRI values at various Brix degrees for white and red grape juices and concentrates.     

The effects of some manufacturing factors on surface roughness of sliced Makoré (Tieghemella heckelii Pierre Ex A.Chev.) and rotary-cut beech (Fagus orientalis L.) Veneers

In this study, the effects of veneer thickness, cutting speed, knife bevel, vertical and horizontal opening, and drying temperature on surface roughness of sliced Makore veneer and rotary-cut beech veneer were evaluated. Makore logs for sliced veneers and beech logs were used for rotary-cut veneers manufacturing. Before veneer manufacturing, the Makore and beech logs were steamed indirectly at 80 °C for 50 and 36 h, respectively. Roughness measurements were conducted according to DIN standard 4768 by using stylus profilometer. The sliced radial and tangential veneers were grouped and evaluated separately. Results showed that veneer thickness, cutting speed and knife bevel had a significant effect on surface roughness for the sliced veneers, but veneer drying temperature did not affect significantly the surface roughness. In general, surface roughness of the veneer increases with increasing veneer thickness. However, increases in cutting speed decreased the surface roughness. The most suitable knife bevel was 17.5° for manufacturing sliced veneers from Makore. For rotary-cut veneers, vertical and horizontal opening had a significant effect on the surface roughness. The results indicated that vertical opening should be about 50% and horizontal opening about 80–90% of veneer thickness to minimize the surface roughness in manufacturing rotary cut veneer from oriental beech.     

Determination of sympathovagal balance in ventricular tachiarrythmia patients with implanted cardioverter defibrillators using wavelet transform and MLPNN

HRV is a nonstationary signal that includes sympathovagal balance (SB) information related to LF/HF ratio between the sympathetic and parasympathetic nervous systems. In this paper, a solution based on Daubechies wavelet transform (dbN) and multilayer perceptron neural network (MLPNN) has been presented for the determination of SB. HRV database obtained MIT-BIH arrhythmia database consisting of pairs of RR interval time series, recorded by implanted cardioverter defibrillators in 78 subjects. RMS values of approximation and detail components (Arms and Drms) obtained from dbN wavelet transform of HRV signals have been used as training data for MLPNN. Trains were realized in 5 different dbN with only Arms components, only Drms components and both of them and results were compared. Train accuracy and test accuracy results have been reached very successful percentage values that might be valuable for clinical applications.     

A direct borohydride–peroxide fuel cell–LiPO battery hybrid motorcycle prototype – II

In this study, a direct borohydride–peroxide fuel cell (DBPFC)–LiPo battery hybrid motorcycle, called HYBROTO, was developed. The hybrid system was designed using a 10-cell DBPFC stack with 120 W of maximum power as the main power source, a 12 LiPo battery pack with 6300 mAh and 65 C for energy storage and as auxiliary power source, and a brushless DC (BLDC) motor. In addition, a voltage-monitoring integrated circuit for fuel cells, a battery management unit, and a motor control circuit were developed to command the DBPFC, LiPo battery, and BLDC motor, respectively. The hybrid system was managed and synchronized by a main control unit (MCU) containing a synchronous bidirectional buck–boost converter and a boost converter. For performance tests, the DBPFC–battery system and BLDC motor were installed in an electric motorcycle body. Performance tests were carried out in the hybrid system under a constant load of 60 W. The hybrid system showed a satisfactory performance under the constant load with an efficiency of 67%. However, the MCU requires further improvement to provide more stable power output. The motorcycle prototype was tested at the 2016 International Symposium on Sustainable Aviation organized by the Sustainable Aviation Research Society.     

An aluminum/cobalt/iron/nickel alloy as a precatalyst for water oxidation

Among different strategies, water splitting toward hydrogen production is a promising process to store energy from intermittent sources. However, the anodic water oxidation is a bottleneck for water splitting. In this paper, we report an aluminum/cobalt/iron/nickel alloy as a precatalyst for the electrochemical water oxidation. The alloy electrode contains different metal ions including cobalt, iron, and nickel which all are efficient for water oxidation is tested. We characterized this electrode using scanning electron microscopy, transmission electron microscopy, diffuse reflectance infrared Fourier transform spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and electrochemical methods. After stabilization, the electrode shows an onset overpotential of 200.0 mV and affords a current density of 3.5 mA cm^?2 at an overpotential of 600.0 mV in KOH solution at pH 13.