Synthesis,microstructural investigation and compaction behavior of Al0.3CrFeNiCo0.3Si0.4 nanocrystalline high entropy alloy

This research article focused on developing Al_0.3CrFeNiCo_0.3Si_0.4 nanocrystalline high-entropy alloy (HEA) by mechanical alloying. The initial powders mixture was ball milled for 1 hr (HEA-1 h), 5 hr (HEA-5 h), 15 hr (HEA-15 h) and 25 hr (HEA-25 h) at ball to powder mass ratio (BPR) of 15:1 and a speed of 300 rpm. The mechanical alloying time was varied from 1 to 25 hr to ensure the nanocrystalline nature and attainment of steady state in HEA powders. The structure of the developed HEAs was characterized by means of X-ray diffraction (XRD), Laser particle size analyzer (LPSA), and various electron microscopes (TEM and FEGSEM with EDS). HEA-25hr sample exhibited the crystallite size of 13.8 nm with lattice strain of 0.67% obtained from XRD which matched the result by TEM. The formation of a solid solution (SS) with a uniform elemental dispersion was observed with a major BCC stable structure and a minor FCC structure in HEA-25 h sample. The HEA-25 h sample revealed an average particle size of 386.2 nm (89.8% peak intensity) with Polydispersity Index (PDI) value of 0.364 which confirmed the uniform distribution of particles over a narrow range of particle size. The synthesized powders were consolidated to green compacts with a loading rate of 1 mm/min at different compaction pressures (25, 50, 75, 100, 150, 200, 400, 600, 800, 1000, and 1100 MPa) for examining the powder particles packing. Several compaction models (both linear and non-linear) were discussed to establish the density-pressure relationship of developed HEAs. The results revealed that the milling time has influenced the relative density. HEA-1 h sample was exhibited the relative density of 0.76 whereas HEA-25 h sample was produced the relative density of 0.6 indicating more strength and more amount of strain hardening occurs in MAed HEA-25 sample in addition to the entropy effect for the same composition.     

Neuro-wavelet based intelligent medical image fusion

Imaging based sensitive clinical diagnosis is critically depending on image quality. In this article, the problem of enhancing fundus images is addressed by a novel fusion technique. The proposed approach utilizes the representation capability of wavelet transform and the learning ability of artificial neural networks. In this approach, input images are decomposed into wavelet transform followed by appropriate feature extraction for training of neural networks to obtain fused image. To ensure homogeneity, it employs consistency verification for minimizing the fusion artifacts. The visual and quantitative performance of the proposed approach is assessed using a number of experiments performed on the standard datasets of DRIVE and DRION-DB. The experimental results demonstrate that the proposed fusion technique offers high average structural similarity of “0.99.” The proposed approach outperforms state-of-the-art techniques which validates its effectiveness. The developed approach might be applied by the clinical diagnosis system for fundus related diseases.     

Eu3+, Sm3+ Deep‐Red Phosphors as Novel Materials for White Light‐Emitting Diodes and Simultaneous Performance Enhancement of Organic–Inorganic Perovskite Solar Cells

The luminous efficiency of inorganic white light‐emitting diodes, to be used by the next generation as light initiators, is continuously progressing and is an emerging interest for researchers. However, low color‐rendering index (Ra), high correlated color temperature (CCT), and poor stability limit its wider application. Herein, it is reported that Sm³⁺‐ and Eu³⁺‐doped calcium scandate (CaSc₂O₄ (CSO)) are an emerging deep‐red‐emitting material with promising light absorption, enhanced emission properties, and excellent thermal stability that make it a promising candidate with potential applications in emission display, solid‐state white lighting, and the device performance of perovskite solar cells (PSCs). The average crystal structures of Sm³⁺‐doped CSO are studied by synchrotron X‐ray data that correspond to an extremely rigid host structure. Samarium ion is incorporated as a sensitizer that enhances the emission intensity up to 30%, with a high color purity of 88.9% with a 6% increment. The impacts of hosting the sensitizer are studied by quantifying the lifetime curves. The CaSc₂O₄:0.15Eu³⁺,0.03Sm³⁺ phosphor offers significant resistance to thermal quenching. The incorporation of lanthanide ion‐doped phosphors CSOE into PSCs is investigated along with their potential applications. The CSOE‐coated PSCs devices exhibit a high current density and a high power conversion efficiency (15.96%) when compared to the uncoated control devices.     

Maximal atom–photon entanglement in a double-$$\Lambda $$ quantum system

The atom–photon entanglement of a dressed atom and its spontaneous emission in a double-\(\Lambda \) closed-loop atomic system is studied under multi-photon resonance condition. It is shown that even in the absence of quantum interference due to the spontaneous emission, the von Neumann entropy is phase-sensitive and it can be controlled by either intensity or relative phase of the applied fields. It is demonstrated that for the special case of Rabi frequency of the applied fields, the system is maximally entangled. Moreover, an open-loop configuration is considered, and it is shown that the degree of entanglement can be controlled by intensity of the applied fields. Furthermore, in electromagnetically induced transparency condition, the system is disentangled. Such a system can be used for quantum information processing via entanglement using optical switching.     

Introducing a Novel Hybrid Machine Learning Model and Developing its Performance in Estimating Water Quality Parameters

Water Resources Management - For the first time, a novel hybrid machine learning model named the least-squares support vector machine-arithmetic optimization algorithm (LSSVM-AOA) was proposed. The...     

Mixed oxide nanotubes in nanomedicine: A dead-end or a bridge to the future?

Nanomedicine has seen a significant rise in the development of new research tools and clinically functional devices. In this regard, significant advances and new commercial applications are expected in the pharmaceutical and orthopedic industries. For advanced orthopedic implant technologies, appropriate nanoscale surface modifications are highly effective strategies and are widely studied in the literature for improving implant performance. It is well-established that implants with nanotubular surfaces show a drastic improvement in new bone creation and gene expression compared to implants without nanotopography. Nevertheless, the scientific and clinical understanding of mixed oxide nanotubes (MONs) and their potential applications, especially in biomedical applications are still in the early stages of development. This review aims to establish a credible platform for the current and future roles of MONs in nanomedicine, particularly in advanced orthopedic implants. We first introduce the concept of MONs and then discuss the preparation strategies. This is followed by a review of the recent advancement of MONs in biomedical applications, including mineralization abilities, biocompatibility, antibacterial activity, cell culture, and animal testing, as well as clinical possibilities. To conclude, we propose that the combination of nanotubular surface modification with incorporating sensor allows clinicians to precisely record patient data as a critical contributor to evidence-based medicine.     

Memristive fuzzy edge detector

Fuzzy inference systems always suffer from the lack of efficient structures or platforms for their hardware implementation. In this paper, we tried to overcome this difficulty by proposing a new method for the implementation of the fuzzy rule-based inference systems. To achieve this goal, we have designed a multi-layer neuro-fuzzy computing system based on the memristor crossbar structure by introducing a new concept called the fuzzy minterm. Although many applications can be realized through the use of our proposed system, in this study we only show how the fuzzy XOR function can be constructed and how it can be used to extract edges from grayscale images. One main advantage of our memristive fuzzy edge detector (implemented in analog form) compared to other commonly used edge detectors is it can be implemented in parallel form, which makes it a powerful device for real-time applications.     

Spatially homogeneous gelation in liquid composite molding

On‐line mixing of the resin with its curing agents prior to injection into a mold is a common industrial technique for fabricating composite parts. For vinyl‐ester resins that cure via free radical polymerization, the concentrations of retarder, accelerator, and initiator are pre‐selected and cannot be changed during the injection. Hence, the resin that enters the mold the earliest has cured longer than the resin that enters the mold later, since the gel time for the resin is the same, owing to the fixed ratio of the curing agents. This approach leads to inhomogeneous cure of the resin and consequently to longer residence time of the resin in the mold. It requires an additional 50 to 75 percent of the filling time before a part can be de‐molded. In this study, it is shown that by adjusting the concentration of curing agents during the injection, a more homogeneous gel time throughout the mold can be achieved. The time to de‐mold is reduced to 18‐24 percent of the filling time. Sensors that measure the conductivity of the resin were used to detect the location and monitor the cure of vinyl‐ester. This approach could be extended to other resin systems to control the spatial curing of the resin in the mold.     

Rheological/thermal properties of poly(ethylene terephthalate) modified by chain extenders of pyromellitic dianhydride and pentaerythritol

Due to low molecular weight and wide molecular weight distribution, polyethylene terephthalate (PET) shows weak melt strength properties. In this study, the synergistic effect of using different types of chain extenders and catalyst on rheological behavior of PET has been investigated. Long-chain branching is known as a suitable method for developing the structure of PET during reactive melt processing. Thus, pyromellitic dianhydride (PMDA) and pentaerythritol (PENTA) were added to the fiber grade PET. The best formulation was determined based on rheological results, which revealed an improvement in both storage modulus and complex viscosity of PMDA-modified samples. Samples containing 1.5% PMDA and 0.5% PENTA exhibited the best rheological properties. Also, dibutyltin dilaurate (DBTDL) acted as an accelerator for chain extension reaction during reactive melt blending. Subsequently, the rheological properties were improved by increasing the chain extending rate. Moreover, thermal properties such as crystallization and melting temperatures and the degree of crystallinity for modified PET were investigated by differential scanning calorimetry.     

Increasing power efficiency in the design of a low power and low phase noise CMOS LC oscillator

This study developed a local oscillator (LO) with low phase noise and low power consumption. The proposed oscillator core comprises a pair of cross‐coupled transistors, which are fed by another pair of transistors that injects current at moments close to the peak of output voltage. The position of the current injection transistors, which are inserted in series with the cross‐coupled transistors, affects the waveform of current injected into an inductive–capacitive (LC) tank. Installing a capacitor on the source node of the cross‐coupled transistors increases the current injected into the LC tank and thereby augments the output voltage amplitude and power efficiency of the LO. The resonator phase shift and Q can be corrected by adjusting the source capacitance, which filters noise. These changes reduce the phase noise to ?123.4 dBc/Hz at a frequency offset of 1 MHz and improve oscillator performance with a figure of merit equal to ?193.5 dBc/Hz. To evaluate the LC tank, a 5 GHz LO was simulated at 1.8 V power supply and 2.5 mW power consumption. The simulation was conducted using a practical 0.18 complementary metal–oxide–semiconductor model manufactured by the Taiwan Semiconductor Manufacturing Company. The simulation results confirmed the analytical findings.