Low Current Values Research Articles

Biosensor for electrochemical detection of biomarkers of osteoarthritis

Biosensor for electrochemical detection of biomarkers of osteoarthritis

Carbon dopants carriers facilitators as agents for improving hole extraction efficiency of cobalt tetraoxide nanoparticles employed in fabrication of photodetectors

(CH3NH3)3Bi2I9 perovskites have attracted enormous attention due to their lower toxic and more stable nature than CH3NH3PbI3 counterparts. However, higher bandgap and lower carrier mobility hinder the application of (CH3NH3)3Bi2I9 in optoelectronics. Hence, we employed carbon doping of Co3O4 hole extractors to reduce the bandgap of (CH3NH3)3Bi2I9, minimize non – radiative recombination rate and improve surface morphology of the (CH3NH3)3Bi2I9 particles. Consequently, photodetectors based on carbon-doped Co3O4 display reduced internal resistance, high photocurrent and low dark current values. The fabricated photodetectors display high responsivity (1.56 × 106 μA/W), high detectivity (5.74 × 1012 Jones), high sensitivity (8.23 × 103) and fast optical switching times (< 10 ms) values under device testing conditions of 2.0 V bias voltage, 10 mW/cm2 power intensity of solar illumination and ambient room conditions. The linearity and stability of the photodetectors over wide range of light intensities and 100 optical switching cycles were also demonstrated respectively.

The potential value of recycling municipal household solid waste in Shanghai, China

ABSTRACT The recycling of municipal household solid waste (MHSW) is important for the environmental preservation and wellbeing of the society. In recent decades, continuous efforts in research, policy-making and municipal administration have led to improvements toward more sustainable MHSW recycling. However, MHSW recycling remains a major challenge for China. This paper analyzes the current value and potential value of MHSW recycling in order to guide residents to recycle MHSW effectively and to reduce the amount of recycle-worthy materials missing recycling. A multivariate probit model is developed to ascertain the current value and potential value of MHSW recycling. Results from a case study of Shanghai reveal that waste glass has low current value and low potential value, and waste plastics has low current value but high potential value. The results also indicate that the waste metal has high current value and high potential value, whereas waste paper has high current value but low potential value. These findings provide policymakers with useful information and rationale for directing efforts to achieve a better or optimal MHSW recycling practice. Implications: Be a multivariate probit model is developed to calculate the current value and potential value of MHSW recycling in order to guide residents to recycle MHSW and reduce an amount of miss-recycling materials. Our results have shown that waste glass has a low current value and a low potential value, waste plastics have a low current value and a high potential value. Regarding the waste metal, they have a high current value and a high potential value. For waste papers, the result indicates that it has a high current value and a low potential value.

Genetic evolutionary approach for surface roughness prediction of laser sintered Ti–6Al–4V in EDM

Abstract Additive Manufacturing (AM) methods, in the field of production, are increasing rapidly. In particular, the use of Ti alloys has an important role in AM methods. The major disadvantage of AM methods is low surface quality of the manufactured parts. Therefore, parts produced using AM methods need subsequent surface treatment. Electro Discharge Machining (EDM) is one of the nontraditional machining methods, which can be used to improve the surface quality with appropriate parameters. In this study, EDM was investigated to improve the surface quality of sintered Ti–6Al–4V alloy by using 160 different finish parameters. It was observed that Current (I) has a notable effect on surface roughness showing that best surface quality is achieved with low current values, which is under R a = 2 µm. To estimate the final result of EDM, roughness values obtained from the experiments were modeled by using the Genetic Expression Programming (GEP), and a mathematical relationship between the obtained roughness values and EDM parameters was proposed. As a result of 830,900 iterations, GEP model created can estimate the final surface roughness of the parts with 84% accuracy.

Flexible and high-performance broadband nanoflowers tin sulfide photodetector

A significant prerequisite for the development of a high-performance photodetector remains its low dark current value, because it promotes sensitivity and signal-to-noise ratio, in addition to low detectability light power density. Nevertheless, the fabricated photodetectors, which are based on deposited tin sulfide (SnS) films onto a flexible (PET at pH 5) and glass substrates, exhibited relatively high dark current values around (0.2 µA) and (several µA), respectively. This study proposes a novel approach for a better control of the photoresponse characteristics of nanostructured SnS film which resulted from reducing the deposition growth rate by adjusting the pH of the reaction solution to 5.8. The film was deposited onto a flexible substrate of polyethylene terephthalate (PET) using an inexpensive chemical bath deposition method. The as-fabricated photodetector exhibited a low dark current value approximately (~ 24 nA) at 5 V bias voltage and a good response in a broad range covering the UV up to the near-infrared. Besides, light-emitting diodes (380, 530, 750, and 850 nm) were used to investigate the photoresponse characteristics of the photodetector. The latter manifested fast photoresponse times (rise and decay) and good sensitivity for all used illumination wavelengths. Furthermore, under various illumination power densities of 850 nm, the photocurrent manifested a good dependence upon power density. Based on the obtained excellent photoresponse characteristics, this photodetector is promising for the photoelectronic flexible device in the UV–Vis–NIR range.

The Influence of the Conditions of Getter Formation in High-Resistivity Silicon on the Characteristics of PIN Photodiodes

The influence of the conditions of gettering in high-resistivity silicon during fabrication of PIN photodiodes on reverse dark currents has been studied. It is shown that gettering using a combination of phosphorus ion implantation and deposition of a polysilicon film with subsequent doping of the substrate rear side with phosphorus at temperatures below 900°C leads to low values of the reverse dark current and increases the nonequilibrium carrier lifetime.

Non‐local harmonic current and reactive power compensation for a multi‐microgrid system using a series–shunt network device

In this study, a new non-local active compensation method is developed for a multi-microgrid (MMG) system. The current industry practice is to utilise local harmonic current and reactive power compensation methods, however, local compensation methods are not practical for large MMG system with widely dispersed non-linear loads, because each non-linear load would require its own compensator. To overcome this problem, a novel compensating technology called a series–shunt network device (SSND) is installed between a pair of microgrids in the proposed MMG system. The SSND reduces the number of local compensators required while also performing additional functions in comparison with conventional devices. For effective control of the SSND, an improved model predictive control (MPC) algorithm, which gives better tracking accuracy and faster set-point change than that of a conventional proportional–integral controller, is also presented. Analysis and simulations verify the capability of SSND in performing both local and non-local active compensation of harmonic current and reactive power in the proposed MMG system under various test scenarios. Simulation results show that the MPC-controlled SSND can achieve effective compensation, thereby resulting in a very low current total harmonic distortion value of 2.4% and a unity power factor at the distribution grid side.

Vortex domain wall dynamics in stepped magnetic nanowire with in-plane magnetic anisotropy

Controlling Vortex Domain wall (VDW) dynamics and stability in a stepped nanowire with in-plane magnetic anisotropy was investigated by using micromagnetic simulation with fixed nanowire dimensions. A stepped area is constricted at the center of the nanowire with proportions of length (d = 50 nm) and width (λ = 50 nm) to pin the magnetic domain wall (DW) with high barrier potential energy to achieve a high information storage capacity. From this study, it was found that the DW with different structures was pinned at the stepped area with high stability. Also, a reduction of VDW behaviors due to its chirality and polarity has been obtained according to saturation magnetization (Ms). By increasing the values of Ms, the VDW attraction to the nanowire edges based on its chirality and polarity becoming less and VDW moves in a straight line towards the stepped area. Therefore, with high values of MS, the VDW is stable in type and moves towards the stepped area with a speed of 500 m/s until pinning there. In addition, the symmetry of the stepped area design helps the VDW to move in a straight line through the stepped area and maintain its magnetization configuration during the depinning. This is important for writing and reading the information in storage memory devices.Furthermore, current density values (J) have affected the stability of the VDW by decreasing the VDW behaviors regarding its chirality and polarity. With low driven current density values, the VDW kept its structure until reaching and got pinning at the stepped area. Further investigations were done to examine the transverse domain wall (TDW) and VDW depinning through the stepped area. The results have shown that TDWs have a high barrier potential than VDWs.

Electrodeposition of Photocatalytic Sn–Ni Matrix Composite Coatings Embedded with Doped TiO2 Particles

Direct current electrodeposited Sn–Ni/TiO2 nanostructured coatings were produced by embedding two different doped types of TiO2 particles within the alloy matrix, a commercially available doped carbon-based and doped N,S-TiO2 particles. The structural characteristics of the composite coatings have been correlated with the effect of loading, type of particles in the electrolytic bath, and the applied current density. Regardless of the type of doped particles TiO2, increasing values of applied current density resulted in a reduction of the co-deposition percentage of TiO2 particles and an increase of Tin content into the alloy matrix. The application of low current density values accompanied by a high load of particles in the bath led to the highest codeposition percentage (~3.25 wt.%) achieved in the case of embedding N,S-TiO2 particles. X-ray diffraction data demonstrated that in composite coatings the incorporation of the different types of TiO2 particles in the alloy metal matrix modified significantly the nano-crystalline structure in comparison with the pure coatings. The best photocatalytic behavior under visible irradiation was revealed for the composite coatings with the highest co-deposition percentage of doped N,S-TiO2 particles, that also exhibited enhanced wear resistance and slightly reduced microhardness compared to pure ones.

Oxidation and Corrosion Resistance of NiCr-Re and NiCr-Re-Al2O3 Materials Fabricated by Spark Plasma Sintering

The thermal and oxidation resistance of elements found in the combustion boilers of power generation plants are some of the most important factors deciding their effectiveness. This paper shows the experimental results of the influence of NiCr-based material composition on the microstructure and phase changes occurring during the oxidation and corrosion process. NiCr alloy was modified by the addition of rhenium and aluminum oxide. Materials were densified using the spark plasma sintering method at a sintering temperature of 1050 °C. Oxidation tests conducted up to 1100 °C under synthetic airflow revealed the formation of a thin Cr2O3 layer protecting the material against in-depth oxidation. Results of electrochemical corrosion in a 0.5 M NaCl solution indicated a positive role of Re and Al2O3 addition, confirmed by low corrosion current density values in comparison to the other reference materials. According to the provided positive preliminary test results, we can conclude that a NiCr-Re-Al2O3 system in coating form was successfully obtained by the plasma spraying method.

Impedance Angle-Based Differential Protection Scheme for Microgrid Feeders

The emerging trends in the microgrid development and the increasing penetration of distributed energy resources (DERs) in the distribution networks urge the modification in the existing conventional protection techniques. The integration of DERs changes the radial nature of the network, and thus, the schemes designed for such networks fail to operate for the microgrid system. Hence, a new fault detection technique is required for the microgrid system. In this article, a new fault detection scheme is developed for detecting the low-impedance faults (LIFs) as well as high-impedance faults (HIFs). The detection of HIFs is of major concern as these faults lead to a very low fault current value, which makes them undetectable by the conventional overcurrent relays. The proposed scheme uses the cumulative sum value of the differential negative-sequence impedance angle (DNSIA) as the fault detection parameter for generating the trip signal. The simulation results show that the proposed method effectively detects LIFs and HIFs accurately. The proposed scheme is independent of the type of faults, type of DGs, and the value of fault impedances. Furthermore, the proposed scheme also discriminates between the switching transients and faults effectively. The IEEE 13-bus test system is modeled and simulated on real time digital simulator (RTDS)/RSCAD platform. The method is further validated for the real-time implementation by developing the experimental setup for performing the control hardware-in-the-loop.

Study on the noise characteristics of GaAs-based blocked-impurity-band (BIB) detectors

Terahertz (THz) photodetector has attracted great attention from worldwide scientists for its applications in security check, biomedical treatment, and astronomical observation. In the performance evaluation of the THz photodetector, the noise level is one of the critical parameters. The Gallium Arsenide (GaAs) blocked-impurity-band (BIB) detector, which is fabricated from intrinsic GaAs-based photoconductive detectors, reveals an attractive advantage of low dark current value and high signal to noise ratio (SNR). In this work, the epitaxial GaAs BIB detector was fabricated and its noise behavior under various bias was investigated at the temperature of 3.5 K. The measured noise consists of flicker noise (1/f noise), shot noise, thermal noise and measurement noise. The effect of bias and operation temperature (TOpe) on the noise characteristics of a GaAs-based BIB detector has been studied by numerical simulation for suppressing device noise. According to the simulation, the total noise gradually increases with TOpe, and dominated by the shot noise. Our work may provide useful theoretical support to solve the critical epitaxial growth bottleneck of GaAs BIB detector and improve its performance for the applications of astronomical observation, security check, etc.

Corporate Linkages and Financial Performance: A Complex Network Analysis of Indian Firms

Corporate governance has a significant impact not only on the behavior and performance of a corporation but also on the functioning of other corporations, entrepreneurialism in the economy, and the working of capital markets. One way of looking at the effects of corporate governance on company performance is to study the contributions of the corporate board of directors. In this article, we explore the network of the director boards for the top Indian corporations to better understand the effects of the interlocking of management boards when the financial performance is considered. To study the corporate networks, we collected and analyzed relevant data set of the top 150 Indian companies on the basis of the maximum revenue generation. We find that the debt-to-equity ratio (D/E), on average, tends to decrease as the measure of the degree centrality of certain corporations increases. Furthermore, we study a modularity maximization-based community structure of the network of director boards to better comprehend the interconnections of the Indian corporates. Moreover, the underlying relationship between the modularity and the corporate performance is also analyzed, and it can be observed that most of the top Indian corporations, with low net current asset value per share, belong to the larger communities.

MODELLING OF SPINTRONIC DEVICES FOR APPLICATION IN RANDOM ACCESS MEMORY

The article analyzes the physical processes that occur in spin-valve structures during recording process which occurs in high-speed magnetic memory devices. Considered are devices using magnetization of the ferromagnetic layer through transmitting magnetic moment by polarized spin (STT-MRAM). Basic equations are derived to model the information recording process in the model of symmetric binary channel. Because the error probability arises from the magnetization process, a model of the magnetization process is formed, which is derived from the Landau-Lifshitz-Gilbert equations under the assumption of a single-domain magnet. The choice of a single-domain model is due to the nanometer size of the flat magnetic layer. The developed method of modeling the recording process determines the dependence of such characteristics as the bit error probability and the rate of recording on two important technological characteristics of the recording process: the value of the current and its duration. The end result and the aim of the simulation is to determine the optimal values of the current and its duration at which the speed of the recording process is the highest for a given level of error probability. The numerical values of the transmission rate and error probability were obtained for a wide range of current values (10–1500 μA) and recording time of one bit (1–70 ns), and generally correctly describe the process of information transmission. The calculated data were compared with the technical characteristics of existing industrial devices and devices which are the object of the scientific research. The resulting model can be used to simulate devices using different values of recording currents: STT-MRAM series chips using low current values (500-100 μA), devices in the stage of technological design and using medium current values (100–500 μA) and devices that are the object of experimental scientific research and use high currents (500–1000 μA). The model can also be applied to simulate devices with different data rates, which have different requirements for both transmission speed and bit error probability. In this way, the model can be applied to both high-speed memory devices in computer systems and signal sensors, which are connected to sensor networks or connected to the IoT.

High performance hydrogen/oxygen terminated CVD single crystal diamond radiation detector

We report the performance of a single crystal diamond radiation detector with gold films on hydrogen-terminated diamond as electrical contacts and oxygen-terminated diamond as surface isolation between electrodes. The origin-symmetric current-voltage characteristics showed excellent Ohmic contact behavior. An extremely low dark current value of 7.46 × 10−13 A/mm2 was measured at an electric field of 1 V/μm. The charge collection efficiency and energy resolution of this detector were 99.01% and 1.5% for holes, and 98.6% and 1.7% for electrons under irradiation with 241Am α-particles. Under 60Co γ-ray irradiation with a dose rate of 1.271 Gy/s, the gain factor, specific sensitivities, and signal-to-noise ratio were 49.46, 12.43 μC/Gy·mm3, and 1 × 106 at 200 V bias voltage (0.66 V/μm), respectively. A rise time of 347.4 ps of the response to a pico-second pulsed electron source was also measured. This research provides a possibility to improve the performance of the diamond radiation detector through diamond surface modification.

Spinner with fan and Arduino for assembly of organic light emitting diodedevices

In this work, a spinner apparatus was mounted with some characteristics, as: low cost, easy operation, compact size, easy adaptation into the little glove box systems, no vacuum pump and low maintenance. Firstly, three different fans wereanalyzed to be used in thespinner apparatus. Then, the Arduino electronic circuit was analyzed and programmed to control the rotation speed using a pulse width modulation (PWM) and steps of acceleration with the signal distortion (caused by pulse width modulation) of thefan intern tachometer. After, the interface between the user and spinner apparatus was performed with information about: navigation through the menus; input of process parameters as rotation speed; rotation time and calibration menu. Successive depositions of organic thin films to assembly of OLED deviceswere used with the spinner apparatus. The experiment compared ITO (indium tin oxide) thin filmanodes with sheet resistances of 8 and 12 ?/? supplied by different manufacturersin the structure of the OLEDs.I-V curves of OLED devices showed that the ITO/glass of 12 ?/? presented better results with low variabilityand highest current values. All OLED devices presented some luminance showing the efficiency of spinner apparatus.

Corona Loss Minimization on High Voltage Transmission Line Network using Bundled Conductors.

Electrical power generated and transmitted at a long distance away from the power stations is usually affected by inherent transmission line losses. The Ohmic and Corona losses which are predominantly common in power transmission lines are considered in this paper. These two losses are mathematically modeled with and without embedded bundled conductors. The resultant model which is a non-linear multivariable unconstrained optimized equation is minimized using the Hessian matrix determinant method for stability test purposes. The results obtained show that corona losses are minimized with embedded bundled conductors at a very low current value with large spacing distance between the bundled conductors. The decrease in the corona loss which is a consequence of spacing adjustment of the 2, 3, and 4 strands of bundled conductors was plotted using MATLAB 7.14. The plots obtained are in conformity with the inverse relation between corona loss and conductor spacing.

Study of the Voltage Behavior of Jointless Superconducting 2G Loops During Pulse Magnetization

Low critical temperature superconducting coils can conduct persistent currents with almost no losses, as the technique to make joints is well developed and the resistive losses are negligible. The replacement of these superconductors by high-temperature superconductors may greatly reduce refrigeration costs. However, even though the technique for making these joints has greatly developed over the last years, there are still inherent difficulties associated to that process. Coils made with partially slit loops of high temperature superconducting tape have no joints, and therefore can conduct current in persistent mode. Since there are no terminals, its current must be induced through magnetization techniques, for instance, by the means of a transformer. The occurrence of persistent current is related to the voltage in the sample, making it interesting to study the voltage behavior for different regions of operation. In this work, a jointless 2G loop was magnetized with pulse magnetization from which the curves of voltage and current as functions of time were obtained. After several tests, it was possible to divide the superconductor behavior into three different stages of operation, depending on the current levels reached: for low current values, the material behaves as a perfect inductor; for current values near the critical current, it behaves as an RL circuit; and for higher values, resistance dependent on the temperature has to be taken into account. A direct relation between persistent current and the arise of a dissipative state was noted and the highest values of persistent current were observed when the pulse was intense enough to produce significant temperature variations in the sample.

Создание композиционного материала на основе низкоразмерных углеродных частиц

The article considers the issues of thermal shock resistance of carbon materials. To obtain a composite material, the method of electric arc treatment with a relatively low current value was used. The resulting material and its properties correspond to the concept of a double electric layer at the interface, which is due to the orientation of carbon molecules.

Evidence of magneto-electric coupling and electrical study of CFO modified BNT/BT composites

(1-x)(0.93Bi0.5Na0.5TiO3/0.07BaTiO3)-xCoFe2O4 ((1-x)BNT/BT-xCFO, where x = 0.1, 0.2, 0.3, 0.4 and 0.5) composite samples were synthesized by microwave assisted solid state reaction route and sintered at 1050 °C. X-ray diffraction study showed the presence of ferroelectric/ferromagnetic (FE/FM) phases without any peak of secondary phase. This was further confirmed by SEM study showing the presence of both FE/FM grains distinctly. Frequency dependent dielectric study showed maximum dielectric constant ("r) for the composite sample with x = 0.4. Polarization versus electric field (P-E) loop study revealed that maximum remnant polarization (2Pr = 1.75 μC/cm2) was found also for the 0.6BNT/BT-0.4CFO sample. Remnant magnetization (Mr) of the composite sample with x = 0.4 was found to be ∼7.81 emu/g. Magnetodielectric (MD) study of the 0.6BNT/BT-0.4CFO composite sample showed decrease in "r with the application of magnetic field and a MD effect of ∼2.4% (at 10 kHz) was found. Low leakage current value (∼10−4 A) was obtained in the 0.6BNT/BT- 0.4CFO composite sample. Change in piezoresponse force microscopy contrast after poling indicated on the changes in polarization of the ferroelectric domains. Reduction in Mr, observed in magnetic force microscopy contrast gave a clear evidence of presence of electric field induced magneto-electric (ME) coupling in the 0.6BNT/BT-0.4CFO composite sample.