A Compact Semi-circular Slot MIMO Antenna with Enhanced Isolation for Sub-6 GHz 5G WLAN Applications

In this paper, a novel compact semi-circular slot (SCS) 2 × 2 MIMO antenna is presented for 5G NR sub-6 GHz applications with high isolation. The proposed antenna consists of a semi-circular slot in ground plane, U-shaped stub, and 50-ohm microstrip feed line. The novelty of this paper are the Semi-Circular Slot acts a radiator, the port isolation  is enhanced using a simple conductor strip as a neutralization line, very compact in size, low ECC, and good impedance matching. The overall size of the proposed SCS MIMO antenna is 16 mm x 21 mm, and FR4 substrate is used with thickness of 1.6 mm. The two SCS antenna elements are separated by edge-to-edge distance of 1mm (\(=0.019\lambda _{0}\)). The proposed compact MIMO antenna design is simulated using Ansys HFSS. To validate SCS MIMO antenna, a prototype was fabricated and tested. The measured results are attained at 5.5 GHz with isolation greater than 25dB, impedance bandwidth (S11\(<-10\) dB) covers from 5.10 GHz to 5.80 GHz with return loss of ? 39.5 dB. The MIMO antenna parameters, ECC, CCL, TARC, and MEG are studied, and the values are obtained within acceptable limits. The measured and simulated antenna results are almost similar. This compact MIMO antenna is suitable for 5G communications in sub-6 GHz wifi-5 band applications.

     

Cryptographic Lightweight Encryption Algorithm with Dimensionality Reduction in Edge Computing

Edge Computing is one of the radically evolving systems through generations as it is able to effectively meet the data saving standards of consumers, providers and the workers. Requisition for Edge Computing based items have been increasing tremendously. Apart from the advantages it holds, there remain lots of objections and restrictions, which hinders it from accomplishing the need of consumers all around the world. Some of the limitations are constraints on computing and hardware, functions and accessibility, remote administration and connectivity. There is also a backlog in security due to its inability to create a trust between devices involved in encryption and decryption. This is because security of data greatly depends upon faster encryption and decryption in order to transfer it. In addition, its devices are considerably exposed to side channel attacks, including Power Analysis attacks that are capable of overturning the process. Constrained space and the ability of it is one of the most challenging tasks. To prevail over from this issue we are proposing a Cryptographic Lightweight Encryption Algorithm with Dimensionality Reduction in Edge Computing. The t-Distributed Stochastic Neighbor Embedding is one of the efficient dimensionality reduction technique that greatly decreases the size of the non-linear data. The three dimensional image data obtained from the system, which are connected with it, are dimensionally reduced, and then lightweight encryption algorithm is employed. Hence, the security backlog can be solved effectively using this method.     

Liquid gadolinium corrosion study of TaC coating on tantalum

Spectroscopic information of gadolinium isotopes is necessary to exploit the full potential of various isotopes in nuclear and medical applications. Container materials to handle liquid gadolinium during spectroscopic studies is an important aspect. Tantalum carbide (TaC) has excellent stability and also exhibits superior resistance to attack by various reactive actinide metals at high temperature for long durations. Tantalum crucibles with TaC coating were prepared and tested for compatibility against liquid gadolinium at 1673?K upto 14?h in vacuum. Optical microscopy and SEM/EDS investigations were done to evaluate the micro structural features of the coating and the liquid gadolinium attack. Experimental results show that TaC coating exhibits excellent corrosion resistance against liquid gadolinium at 1673?K.     

From agrowaste to graphene nanosheets: chemistry and synthesis

In recent years, graphene oxide (GO) and reduced graphene oxide (r-GO) are being produced using graphite powder as precursor material but the preparation of graphene derivatives from a non-graphitic material without an additional oxidizing agent has not been reported so far. In this work, an agrowaste namely sugarcane bagasse was subjected to pyrolysis at three different temperatures, bypassing the use of toxic chemicals and graphite as a precursor. The chemistry of the effect of temperature and time on the development of graphitic planes in a non-graphitic material was studied. The formation of nanosheets of GO suggested that aromatization and condensation of the glucose monomers might have taken place which led to the glycosidic bond formation, further converging into polyaromatic rings on pyrolysis. The GO was further reduced at 95?°C using thiourea which resulted in the formation of r-GO after 8?hrs.     

ZnO energy transfer and enhanced photoluminescence in MEH-PPV/ZnO hybrid nanocomposite

Hybrid organic–inorganic nanocomposites are great candidates for display and illumination systems due to improved optoelectronic properties and photostability. This work endeavours towards the scientific study of the influence of defect-induced zinc oxide nanoparticles (ZnO) on the optical characteristics of poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV). ZnO nanoparticles consist of many vacancies which facilitate light emission across the visible region. The green defective emission occurring due to the presence of oxygen vacancies in ZnO was used to re-excite MEH-PPV and hence, improve the luminescence quantum efficiency. The photostability of the nanocomposite was enhanced through charge transfer (prevents the formation of superoxides) and energy transfer (reduces the non-radiative decay) mechanisms.

Graphical abstract

     

Synthesis and Biological Evaluation of Imidazo[2,1‐b][1,3,4]thiadiazole‐Linked Oxindoles as Potent Tubulin Polymerization Inhibitors

A series of imidazo[2,1‐b][1,3,4]thiadiazole‐linked oxindoles composed of an A, B, C and D ring system were synthesized and investigated for anti‐proliferative activity in various human cancer cell lines; test compounds were variously substituted at rings C and D. Among them, compounds 7 ((E)‐5‐fluoro‐3‐((6‐p‐tolyl‐2‐(3,4,5‐trimethoxyphenyl)‐imidazo[2,1‐b][1,3,4]thiadiazol‐5‐yl)methylene)indolin‐2‐one), 11 ((E)‐3‐((6‐p‐tolyl‐2‐(3,4,5‐trimethoxyphenyl)imidazo[2,1‐b][1,3,4]thiadiazol‐5‐yl)methylene)indolin‐2‐one), and 15 ((E)‐6‐chloro‐3‐((6‐phenyl‐2‐(3,4,5‐trimethoxyphenyl)imidazo[2,1‐b][1,3,4]thiadiazol‐5‐yl)methylene)indolin‐2‐one) exhibited potent anti‐proliferative activity. Treatment with these three compounds resulted in accumulation of cells in G₂/M phase, inhibition of tubulin assembly, and increased cyclin‐B1 protein levels. Compound 7 displayed potent cytotoxicity, with an IC₅₀ range of 1.1–1.6 μM , and inhibited tubulin polymerization with an IC₅₀ value (0.15 μM ) lower than that of combretastatin A‐4 (1.16 μM ). Docking studies reveal that compounds 7 and 11 bind with αAsn101, βThr179, and βCys241 in the colchicine binding site of tubulin.     

Development of Novel Iron Crosslinked CMC Nanoadsorbents for the Remediation of Arsenic Ions

Iron crosslinked carboxy methyl cellulose (CMC) nanoparticles prepared by the process of emulsion crosslinking were studied for the removal of arsenic(V) ions from aqueous solution. Batch and column studies were conducted in order to investigate the efficiency of nanoparticles towards arsenic remediation. The Langmuir and Freundlich equations were applied to describe the biosorption isotherm. The results obtained from fixed bed studies showed that the column demonstrates fairly well at lowest flow rate and also, bed exhaustion time was found to increase with increasing bed height. The bed depth service time (BDST) model was used to analyze the experimental data and the model parameters were evaluated. Antibacterial studies were also conducted which confirms that Fe-CMC nanoparticles are efficient towards the removal of bacteriological contamination also.     

Nanomaterials based biofuel cells: A review

Biofuel cells (BFCs) are the devices made to transform the chemical energy of organic matter to electrical energy utilizing metabolic reactions occurring in microorganisms during degradation of organic contaminants. In spite of having many applications such as waste water treatment, biosensors and portable uses of BFCs, promoting the uses of BFCs is very challenging because of short life-time and low-power density. Most of the BFC developed till date is only capable to fulfill energy needs of biomedical short-term implanted devices. Use of materials with nano dimensions in the construction of BFCs has been studied extensively and reported as a worthwhile strategy to increase its efficiency. Usually, it is difficult to achieve efficient electron transfer on planar electrode from biocatalyst due to its non-specific orientational the interface. Nonmaterials provide close wiring for the electron transfer between biocatalyst and electrode. Use of various nanomaterials is the most effective way to decrease the gap between active sites (electron producing area)deep inside the enzyme or proteins and the electrodes to achieve better electron transfer. Also, various nanomaterials are utilized to improve the membrane materials for better electron barrier. Many carbon nanostructures, conducting polymers, metal and metal oxides are promising nonmaterials to enhance the current output from BFC. This review highlights recent progress registered in the development of various nanomaterials for construction of electrode and membranes of biofuel cells for better efficiency. It also emphasized the utilization of different metallic nanomaterials, inorganic nanomaterials, conducting polymer-based nanomaterials and carbon-based nanomaterials such as graphene, fullerenes, and carbon nanotubes.     

Plug-load densities for energy analysis: K-12 schools

Benchmarking plug-load densities is essential to bypass arbitrary and/or incorrect inputs used in building energy analysis. As more building simulationists play a decision-making role for the design team, they tend to lean on building energy standards and guidelines for preliminary inputs such as plug-load densities. It is necessary for building energy standards and rating systems to implement plug-load density benchmarks to reward design teams in their efforts to reduce plug-load energy use. Using case study buildings, this paper establishes benchmark plug-load densities for K-12 schools under two new categories – classrooms with computers and classrooms without computers. Eighteen K-12 schools including 9 elementary, 2 middle, and 7 high schools are assessed for actual plug-load densities. For the same case study buildings, four existing approaches – NREL, COMNET, ASHRAE 90.1-1989, and Title-24 are evaluated for plug-load densities. Results show under- and over-estimation of plug-load densities over actual densities. The development of benchmark for K-12 schools will pave way for instituting targets for trimming plug-load densities in new and retrofit building projects.