Integrated reactive components in power electronic circuits

Methods of integrating capacitive and inductive components into new compact devices are presented. Configurations for integrating various combinations of L-C networks are shown. A example of the construction of an integrated L-C for a series-resonant converter is evaluated both practically and experimentally     

A torque and speed coupling hybrid drivetrain-architecture, control, and simulation

In this paper, a speed and torque coupling hybrid drivetrain is introduced. In this drivetrain, a planetary gear unit and a generator/motor decouple the engine speed from the vehicle wheel speed. Also, another shaft-fixed gear unit and traction motor decouple the engine torque from the vehicle wheel torque. Thus, the engine can operate within its optimal speed and torque region, and at the same time, can directly deliver its torque to the driven wheels. This paper discussed the fundamentals architecture, design, control, and simulation of the drivetrain.     

Atypical case of retroperitoneal paraganglioma parasympaticum coexisting with recurrent bleeding from upper gastrointestinal tract

The authors report a case of 47 years old male who was treated for 1,5 year because of recurrent bleedings from upper GIT. Performed examinations showed the presence of retroperitoneal paraganglioma parasympaticum with multiple metastases in bones. A Zollinger-Ellison syndrome was suspected. The final correct diagnosis was established at last microscopically after surgical excision of the specimens.     

A simple single-step diffusion and emitter etching process for high-efficiency gallium-antimonide thermophotovoltaic devices

A single-step diffusion followed by precise etching of the diffused layer has been developed to obtain a diffusion profile appropriate for high-efficiency GaSb thermophotovoltaic (TPV) cells. The junction depth was controlled through monitoring of light current-voltage (I–V) curves (photovoltaic response) during the post-diffusion emitter-etching process. The measured photoresponses (prior to device fabrication) have been correlated with the quantum efficiencies (QEs) and the open-circuit voltages in the fabricated devices. An optimum junction depth for obtaining the highest QE and open-circuit voltage is presented based on diffusion lengths (or minority carrier lifetimes), carrier mobility, and the typical diffused impurity profile in GaSb.     

Burndown prevention in static power converter equipment

Burndown of static power converter equipment is, fortunately, a rare event. When it does occur it is devastating. Danger to personnel and long-term loss of production are the result. Designers and users of the equipment are, understandably, not inclined to publicize their misfortunes. As a result, few technical papers are written on the subject. Over the years the authors have investigated some burndowns, and heard rumors of others. One author has been present, on more than one occasion, when arcing faults have occurred, fortunately without either burndown or physical injury to personnel. These experiences have provided much information concerning are initiation, burndowns, and their causes. Although the experience on which this article is based relates to low-voltage (<1000 volts), high power (>l MW), phase-controlled converters, the conclusions and recommendations are applicable to all types of low-voltage converters     

High temperature anti‐oxidation behavior of in situ and ex situ nanostructured C/SiC/ZrB2‐SiC gradient coatings: Thermodynamical evolution,microstructural characterization,and residual stress analysis

Nanostructured C/SiC/ZrB₂–SiC oxidation protective gradient coating was prepared by a two‐step reactive melt infiltration method. In order to reduce production cost, ZrB₂ phase was synthesized by the in situ reactive that included low‐cost ZrO₂ and B₂O₃ powders as raw materials. High‐temperature oxidation behavior of coatings was evaluated by isothermal oxidation test at 1773 K in air for 10 hours. Thermodynamical behavior of the coatings at various temperatures during oxidation test and coating process was predicted by HSC Chemistry 6.0 software. Compressive residual stresses of 36.9 MPa and 41 MPa were calculated for in situ and ex situ coatings by Williamson‐Hall method. After 10 hours of isothermal oxidation at 1773K, in situ and ex situ coatings showed 12.84% and 15.69% of weight losses with oxidation rates of 1.87 × 10^?2 g cm^?3 h^?1 and 0.91 × 10^?2 g cm^?3 h^?1, respectively. These results indicated that the oxidation protection ability of the coating produced by the in situ method was very close to ex situ coating.     

Synthesis of a novel sulfonated poly(amide‐imide) and its application in preparation of ultrafiltration PES membranes as a modifier

Sulfonated poly(amide‐imide) (SPAI) copolymer was synthesized, characterized, and blended into poly(ether sulfone) (PES)/dimethylacetamide casting solutions to prepare ultrafiltration membranes. Different weight ratios of the copolymer (0–10 wt %) were mixed in the PES casting solution. The analyses of contact angle and attenuated total reflection‐Fourier transform infrared spectra were used to study hydrophilicity and physicochemical properties of the membrane surface, respectively. The membranes were further characterized by scanning electron microscopy images, ultrafiltration performance, and fouling analyses. The outcomes showed that addition of the SPAI in the PES matrix improved considerably the membranes hydrophilicity. Moreover, with increasing SPAI concentration, the porosity, flux recovery ratio, and pure water permeability of the modified membranes were improved. The pure water flux was increased from 3.6 to 12.4 kg/m² h by increasing 2 wt % SPAI. The antifouling property of the modified PES membranes against bovine serum albumin, tested by a dead‐end filtration setup revealed that bovine serum albumin rejection of the obtained membrane was also enhanced and the antifouling properties of the blending membranes were improved. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46477.     

Improving the reliability of Byzantine fault‐tolerant distributed software‐defined networks

This paper presents a method to improve the reliability and fault tolerance of distributed software‐defined networks. This method is called “BIRDSDN (Byzantine‐Resilient Improved Reliable Distributed Software‐Defined Networks).” In BIRDSDN, a group communication is implemented among the controllers of the whole clusters. This method can detect the crash failure and Byzantine failure of any controller and undertakes a fast detection and recovery scheme to select the controllers to take over the orphan switches. BIRDSDN takes into account the reliability of the nodes considering the failure probability of intracluster and intercluster links, topology, load, and latency. The numerical results show that this approach performs better than the other approaches regarding failure detection, recovery, latency, throughput, reliability, and packet loss.     

Anisotropic optical properties of ZnS thin films with zigzag structure

ZnS sculptured thin films produced by thermal evaporation method using the glancing angle deposition technique at different deposition angles (0, 30, 60, 70 and 80\({^{\circ }}\)) are reported. The structural and optical properties of the prepared samples are investigated systematically using X-ray diffraction (XRD) and UV–VIS spectroscopy techniques. The XRD studies show cubic structure for the prepared films and deposition angle dependence of lattice constants, intrinsic stress, tensile stress and dislocation density. The obtained transmittance spectra in the range 380–850 nm for both s- and p-polarized light at normal incidence angle are used to study the s- and p-refractive indices and in-plane birefringence of the ZnS films. The maximum birefringence is evaluated at incident flux angle \(\alpha = 70{^{\circ }}\). Both the refractive index and packing density of the films decrease with increasing deposition angle, which confirm the structural inhomogeneity and porosity nature of the films.     

Salicylic acid nanoparticles (SANPs) improve growth and phytoremediation efficiency of Isatis cappadocica Desv., under As stress

Arsenic (As) is a toxic metalloid dispersed in the environment and it cause serious toxicity to plants. Salicylic acid (SA) plays an important role in many plant growth processes involved in plant defence against heavy metal or metalloid stress. In the present study, for the first time, chitosan nanoparticles was synthesised, loaded by SA and the positive role of SA on growth and phytoremediation efficiency of Isatis cappadocica against As toxicity were evaluated. The highest arsenate treatment (1200 µM) caused a decrease in plant biomass that, however, its combined application with salicylic acid nanoparticles (SANPs) substantially increase in shoot height, root length and their biomass production compared with As stressed plants. The pretreatment of SANPs by increasing arsenate supply, simultaneously increased the As concentration in roots and shoots of I. cappadocica which reached a maximum of 705 and 1188 mg/kg, respectively. This results suggest that high levels of As stress induce stress status in I. cappadocica which SANPs pretreatment application limit these toxic effects of As. Therefore, SANPs has a significant beneficial effect on the growth and phytoremediation efficiency of I. cappadocica subjected to As stress.Inspec keywords: nanoparticles, nanobiotechnology, botany, toxicology, arsenic, biological techniques, polymersOther keywords: salicylic acid nanoparticles, SANP, plant growth efficiency, phytoremediation efficiency, Isatis cappadocica Desv, arsenic stress, toxic metalloid, plant toxicity, plant defence, metalloid stress, chitosan nanoparticles, plant biomass, shoot height, root length, biomass production, I. cappadocica, As