Micro and Nanosystems - Volume 14, Issue 3, 2022

This work reviews the design challenges of CMOS flash type Analog-to-Digital Converter (ADC) for making high bit resolution, low area, low noise, low offset, and power-efficient architecture. Low-bit resolution flash ADC architecture, high-speed applications, and wide-area parallel comparators are identified on their suitability of the design for ADCs. These are effective in the area and bit resolution. The overview includes bit resolution, area, power dissipation, bandwidth and offset noise consideration for high-speed flash ADC design. A MUX-based two-step half flash architecture is considered for applications requiring 1 GHz 16-bit resolution low area and low power consumption. An advanced comparator, MUX, a high-speed digital-to-analog converter (DAC), and MUX-based encoder are also reviewed. The design of technology-efficient ADC architecture is highly challenging for the analog designer.

Background: The fiber-loop ring-down spectroscopy technique has the benefits of optical fiber sensors and also has many unique advantages. Combined with various sensor structures, the FLRD system can achieve different physical, chemical, and biological sensors. Objective: To find a way to solve the problems of light fluctuation and low sensitivity, high sensitivity, and reliability torsion relative angle measurement system is necessary. Methods: The torsion relative angle measurement is achieved by using the fiber loop ring-down intra- cavity amplification. The sensitivity, correlation coefficient, and repeatability are analyzed with the experiment. Results: The sensitivity and correlation coefficient of the proposed system are 4.05 μs/° and 0.9996, respectively. The repeated experiments show that the standard deviation is 9.592×10^-4. Conclusion: The proposed measurement method provides a way to solve the problems of light fluctuation and low sensitivity and has promising applications in the optically active solutions, fiber radial stress birefringence and polarization state measurement of fiber lasers.

Background: Crystal violet dye is stable and difficult to be biodegraded owing to the existence of the multiple aromatic rings of the crystal violet molecules. Removing crystal violet dye from the wastewater is a major challenge. Objective: The aim of the research is to synthesize barium carbonate/tin dioxide nanoparticles and investigate the photocatalytic performance for the degradation of crystal violet. Methods: Barium carbonate/tin dioxide nanoparticles were synthesized via a facile hydrothermal route without any surfactants. The crystal structure, micro-morphology, size and optical performance of the barium carbonate/tin dioxide nanoparticles were investigated by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy and solid ultraviolet-visible diffuse reflectance spectrum. Results: The size of the barium carbonate/tin dioxide nanoparticles is 20 nm to 200 nm with the band gap of 3.71 eV. The photocatalytic activity of the barium carbonate/tin dioxide nanoparticles was measured by the photocatalytic degradation of crystal violet. The crystal violet degradation efficiency reaches 92.1% with the ultraviolet-visible irradiation time of 8 h using 10 mg barium carbonate/tin dioxide nanoparticles. The crystal violet degradation ratio increases to 96.1% when the dosage of the barium carbonate/tin dioxide nanoparticles increases to 20 mg/10 mL crystal violet dye solution. Active species capture photocatalytic experiments showed that the holes, hydroxyl radicals and superoxide ion radicals are the main active species. Reusability experiments displayed that the barium carbonate/tin dioxide nanoparticles are stable for the crystal violet dye degradation. Conclusion: The barium carbonate/tin dioxide nanoparticles show good photocatalytic performance toward crystal violet under ultraviolet light irradiation.

Background: The rapid synthesis and antimicrobial activity of silver nanoparticles (AgNPs) synthesized using Uraria picta extract were investigated in this paper, and AgNPs were examined for antimicrobial activity against a variety of pathogenic organisms, including bacteria and fungi. Objective: The main objective was to synthesize AgNPs from Uraria picta leaves extract by the technique of green synthesis for antimicrobial evaluation against bacteria and fungi using MIC studies. Methods: The AgNPs were formed by treating an aqueous extract of Uraria picta leaves with silver nitrate (1 mM) solution, and then nanoparticles were synthesized for various studies. Results: The Uraria picta leaves extract can be used for the green synthesis of AgNPs effectively. The absorption band at 425 nm in the UV-Vis spectrum confirmed the synthesis of AgNPs. According to MIC tests, silver nanoparticles exhibited antimicrobial and antifungal properties. This work will provide a better understanding of the development of new antimicrobial and antifungal activities. Conclusion: We utilized Uraria picta aqueous leaves extract to develop a fast, cost-effective, ecofriendly, and simple method for the synthesis of AgNPs, and the nanoparticles synthesized by this plant for the first time demonstrated antimicrobial activity. AgNPs were observed to be spherical and oval in shape, with average particle sizes ranging from 12.54 to 25.58 nm. The antimicrobial activity of AgNPs was confirmed against typhi, Escherichia coli, Bacillus subtilis, and Staphylococcus aureus by a significant zone of inhibition.

Background: Psoriasis, a chronic autoimmune disease, involves the integration of biological and molecular events by hyperproliferation of the epidermal keratinocytes and generation of inflammation markers. Owing to severe complications of synthetic corticosteroids, there is a strong need for a potential and safe alternative. Babchi oil (natural essential oil; BO) may prove to be a promising natural agent for psoriasis. Objective: The aim of the present work was to investigate the safety and efficacy of cyclodextrin nanosponge based babchi oil (BONS) hydrogel on skin annexes. Methods: Babchi Oil Nanosponge Hydrogel (BONS-HG) was fabricated and evaluated. Cell viability studies have been carried out on THP1 cell lines to evaluate cytocompatibility. Irritation potential and in vivo visualization of cutaneous uptake of BONS-HG were carried out using Hen’s Egg Chorioallantoic Membrane Test (HET-CAM) and Confocal Laser Scanning Microscopy (CLSM), respectively. The nano hydrogel was tested in vivo using imiquimod-induced psoriasis mouse model. Results: The in vitro irritation potential of BONS-HG indicated no sign of erythema or irritation, suggesting the safety of prepared hydrogel as topical formulation. CLSM studies advocated targeting of BO to epidermis and dermis. Along with histopathological assessment, evaluation of oxidative stress markers revealed the significant antipsoriatic activity (p< 0.001) of the prepared BONS-HG. Conclusion: The present study amalgamated the advantages of natural essential oil with this approach for skin targeting and provided an effective and safe topical alternative for psoriasis.

Background: Al is the promising candidate for deep UV and longer wavelength range plasmonic applications. But it is difficult to have the pure aluminium nanostructure as it is easily oxidized, forming a thin layer of Al2O3. In this paper, we have evaluated the field enhancement of oxide layer on metallic shell (Al-Al2O3 and Au-Al2O3) for single and dimer core-shell configuration and showed potential of the oxide layer in SERS. Methods: The Finite Difference Time Domain (FDTD) has been used to evaluate the LSPR and field enhancement of single and dimer Al-Al2O3 and Au- Al2O3 nanostructure. Results: The results exhibit the tunable plasmon resonance on varying the inner and outer radii of the Al2O3 shell. A redshift and decrease in enhancement were observed as shell thickness increases, whereas on increasing the core size, the enhancement increases in the case of Au-Al2O3 and decreases in Al- Al2O3 due to quadrupole contribution. But on comparing the Au-Al2O3 with Al-Al2O3 for the same particle size, Al-Al2O3 shows larger enhancement because Au has to compete with its interband transition. Conclusion: By optimizing the thickness of the shell and core size, it can be concluded that an ultrathin shell of Al2O3 can give higher enhancement. With Al as a core metal, the enhancement increases as compared to Au-Al2O3. Since a single Al-Al2O3 nanoshell has shown a huge enhancement we have considered the multimer configuration of two identical nanoshells. Due to coupling between two nanoshells a huge increase in enhancement factor ~1012 was observed for Al-Al2O3 dimer nanoshell in the UV region.

Background: Since (1-x)[Pb(Mg1/3Nb2/3)O3]-(x)PbTiO3 (PMN-PT) ceramic has a high dielectric constant and piezoelectric coefficient, it has been widely investigated for profound applications in electro-optical devices, sensors, multilayer capacitors and actuators. Objectives: The objective of this paper is to study the structural and electrical properties of 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (0.7PMN-0.3PT) ceramic to understand the biphasic structural nature using Rietveld Refinement. Also, it characterises the type of conduction process as well as the role of grain and grain boundary resistance in the material on the basis of electrical properties such as impedance and modulus to understand the relaxation process. Methods: 0.7PMN-0.3PT is synthesised by mixed oxide method using PbO, MgO, Nb2O5 and TiO2 as precursor materials. Results: The XRD data reveals the biphasic structure of the tetragonal phase with the space group of P4mm and the monoclinic phase with the space group of Pm. The complex impedance analysis clearly represents the effect of grain on the overall resistance and departs from normal Debye-type behaviour. Also, the resistance is found to decrease with temperature, thereby confirming the semiconducting nature of the sample. The presence of long as well as short-range mobility of charge carriers is confirmed from the modulus and impedance analysis. The influence of long-range motion is observed at high temperatures and of short-range motion at low temperatures. Conclusion: XRD analysis confirmed the biphasic structure of the M+T phase. The frequencydependent modulus and impedance spectroscopy show the presence of a relaxation effect in the ceramic which is found to increase with temperature. The Nyquist plot shows that the resistance is decreased with temperature, thereby confirming the NTCR behaviour in the studied sample.

Aims: A novel design for non-reversible as well as reversible parity generator and detector in Quantum-dot Cellular Automata (QCA) technology is presented in this research article. Parity generator and detector circuits are reliable error-checking components of a nano-communication system. Objective: The main focus of this research is to design an ultra-low-power fault-tolerant reversible gate implementation of the parity logic function in QCA. An efficient QCA design layout with minimal area, less latency and the least energy dissipation is desired. Method: The proposed designs are developed using Quantum-dot Cellular Automata (QCA) technology. The circuits are optimized using majority gate reduction and clock zone reduction techniques. Also, the cell-cell interaction technique is employed to further optimize the QCA circuit. To increase the fault tolerance and ultra-low power operation, reversible QCA circuits are designed using cascaded Feynman gates. Results: The efficiency of the parity generator and detector is calculated to be more than 25% compared to existing QCA layouts. It is demonstrated in this paper that the proposed circuits perform exceptionally well on every design parameter. The design parameters under consideration are cell count, cell area, complexity, crossover count, latency and energy dissipation. Conclusion: Using reversible logic, a fault-tolerant and defect-sensitive circuit are developed for parity generation and detection.

Aims: Cryptography means 'hidden secrets'. The primary purpose of cryptography is to protect networks and data over a wireless communication channel. The cryptographic approach secures the data of a network from any internal or external attacks. Background: There are several kinds of cryptographic techniques, such as Data Encryption Standard (DES), RSA (Rivest- Shamir- Adleman), Advanced Encryption Standard (AES), Blowfish, Twofish, etc. Out of these algorithms, AES shows wide acceptance for its superiority in providing confidentiality to secret information. Another cause for extensive acceptance is that AES is simple, convenient to implement, has a low charge, and higher security. Several changes have been proposed to modify AES by cryptographers and researchers all around the world. Objective: This research paper offers a new key-dependent s-box generation algorithm for AES. Methods: A list of irreducible polynomials of degree 8 is used to generate the s-box depending on the secret key to provide more invulnerable ciphertext in comparison to standard AES. This design of this proposed model is easy and convenient to implement than different dynamic s-box technology algorithms. Results: The metrics chosen for overall performance evaluation are Frequency Distribution, Chi-square Test, Avalanche Effect, and Strict Avalanche Criterion. Conclusion: The proposed algorithm satisfies the desired property of these metrics and provides better security in contrast to standard AES.

Background: The utilization of high-performance Phase Change Materials (PCMs) that can reversibly store thermal energy is of immense interest and strategy for effective energy conservation and management. Methods: In this work, a new PCM nanocomposite, consisting of a eutectic mixture of stearic acid and n-nonadecane as core and SiO2 as shell, was prepared by direct impregnation method. Additionally, a laboratory scaled test room was designed to investigate the intelligent temperature control function of the nanocomposite in building materials. Results: The optimized nanocomposite was characterized using Fourier Transform Infrared (FTIR) spectroscopy, Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) techniques. The DSC data demonstrated that the PCMs eutectic mixture content in the stearic acid- n-nonadecane–SiO2 nanocomposite was 52.8 wt.% and the melting temperatures and latent heats of stearic acid - n-nonadecane eutectic mixture and optimized nanocomposite were 45.1 and 44.0 °C, and 163.7 and 86.5 J/g, respectively. Furthermore, the accelerated thermal cycling test confirmed the excellent thermal cycling stability of the nanocomposite after 500 heating-cooling cycles. Moreover, the laboratory scaled test room results showed that the incorporation of the resulting nanocomposite in the gypsum could reduce indoor temperature fluctuation, and the performance was improved with the increase in the mass percentage of the nanocomposite in the gypsum composite. Conclusion: The obtained nanocomposite had good thermal reliability and temperature control performance and thus can be a promising candidate for hi-tech applications in intelligent temperature control and precise thermal management.