International Journal Of Nanoscience and Nanotechnology
Volume:18 Issue: 3, Summer 2022

MgO-SiO2 nanoparticle catalyst was prepared, characterized, and evaluated in a fixed-bed reactor for ethanol conversion to 1,3 butadiene (BD) process (ETB). The prepared catalyst was characterized by XRD, XPS, SEM, TEM, EDS, and BET techniques. The data obtained from the surface and bulk characterizations of the prepared catalyst was used to correlate the catalyst morphology and surface chemistry to its performance in ETB. This work investigates the effect of temperature, Hourly space velocity, and water content on ethanol conversion and product selectivity. In addition, MgO-SiO2 pellets with size of 500 µm was prepared and applied into the process to evaluate the impact of the catalyst’s particle size on its efficiency. The catalyst stability was investigated at the optimum reaction conditions for ten hours of the reaction. 1,3-butadiene selectivity of as high as 60% is achieved at the optimum reaction temperature of 400 oC. This high selectivity was attributed to the catalyst’s high surface area and surface functional groups. Increasing the reaction temperature increases the rate of ethylene formation and, therefore, the selectivity for acetaldehyde decreases. Increasing the feed flow rate inhibits the formation of BD and increases the acetaldehyde selectivity. The presence of water was found to be a reducer agent to the BD selectivity due to its emphasis on acetone formation. This work investigated the impact of reducing the MgO-SiO2 catalyst particle size to the nanoscale and provides insightful information about the correlation MgO-SiO2 catalyst properties with its performance in converting ethanol to BD.

This paper presents a procedure to analyze the effects of temperature in CNTFET-based NOT gate using a compact semi-empirical model, already proposed by us. The proposed analysis allows to determine the noise margin and static power in different voltage supplies and temperature conditions. In particular the noise margin decreases and static power increases with temperature, so it can be asserted that low temperature is the most advantageous condition. This is true except for the case 100 K - 200 mV where noise margin is much lower than the expected value due to the double peak in gain function. In terms of power, it should be also noted that decreasing temperature from 200 K to 100 K does not produce any remarkable result. The proposed procedure can be applied to analyze the effects of temperature in the design of A/D circuits based on CNTFET.

Stelechocarpus buharol (BI.) Hook F. & Th leaves were contains flavonoids and have antioxidant activity. This study determined the antioxidant activity, Sun Protection Factor (SPF) value, total phenolic and flavonoid content of ethanol extract (EESL) and purified extract of S. buharol leaves (PESL). EESL was obtained by maceration method and PESL by using n-hexane to remove the non-polar compound then obtain the purified ethanol extract. EESL and PESL were determined the antioxidant activity by using 1,2-diphenyl-2-picrylhydrazyl (DPPH), Ferric Reducing Antioxidant Power (FRAP) and β-carotene bleaching assay (BCB) and classified by using chemometrics of principal component analysis (PCA). The results showed antioxidant activity with DPPH were IC50 value of vitamin C 4.59±0.046 µg/ml, EESL 9.53±0.062 µg/ml and PESL 5.95±0.048 µg/ml, with FRAP method were IC50 values of vitamin C 6.66±0.150 µg/ml, EESL 16.13±0.156 µg/ml and PESL 24.53±0.114 µg/ml and with BCB method were IC50 values of quercetin 236.67±8.808 µg/ml, EESL 134.25±4.478 µg/ml and PESL 116.82±9.982 µg/ml. The SPF value of PESL was 5.70. Total phenolic content of EESL was 5.68 ± 0.042% and PESL was 6.11 ± 0.020%, while the total flavonoid content of EESL 5.62 ± 0.006% and PESL were 6.67 ±0.017%. Based on the results of the study it can be concluded that the results of the measurement of antioxidant activity in EESL and PESL provide good antioxidant activity. The SPF of PSEL at a concentration of 200 ppm of 5.70. The total phenolic and total flavonoid contents correlated with DPPH, FRAP, and BCB. PCA classified EESL and PESL using the variables of antioxidant activities and phenolic-flavonoid contents.

This work synthesized NiO nanoparticles by chemical precipitation and thermal decomposition methods at different annealing temperatures. The properties of synthesized nanopowders were compared by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transformed infrared (FT-IR). The X-ray diffraction pattern analysis indicated that samples annealed at 300℃ and 600℃ have face-centered cubic (fcc) with lattice parameter a= 4.17960  and hexagonal structures with lattice parameters a=b= 2.95  , c=7.23 , respectively. Also, by increasing annealing temperature, the crystallinity and size of NiO nanoparticles have increased, and samples synthesized by the chemical precipitation method have a smaller size than other samples. For 600℃ calcination temperature and compared to other methods, XRD pattern of samples synthesized by thermal decomposition method showed higher intensity of peaks which resulted in larger nanoparticles. FT-IR results confirmed the formation of NiO nanoparticle composition. Also, the FT-IR spectrum of samples synthesized with different methods and varying annealing temperatures didn't change significantly. This enhanced chemical understanding is paramount for the rational control of synthesizing NiO and its applications in electronic and electro-optical research.

A soft error hardened latch is designed, which is based on carbon nanotube field-effect transistors (CNTFETs). The nanoscale circuits are more susceptible to transient or soft errors due to reduced stored charge in their sensitive nodes. Hence, an energy efficient design is a significant challenge, particularly for storage elements like latches. The proposed hardened latch consists of a Schmitt trigger circuit to mask the transient errors, a memory cell, and a C-element with an inverter at its output. The delay element followed by a C-element and a memory cell structure filters single event transient (SET) effectively and has improved robustness against single event upset (SEU). CNTFETs are substituted to gain all the benefits of nanotubes, such as robustness, temperature stability, high speed, and low power consumption. The implementation results in 32nm technology indicate a power consumption of 11.33nW for the supply voltage of 0.9V. The designed latch has low power consumption and lower power-delay product (PDP) concerning the design in CMOS technology. Compared to reported CNTFET latches, the simulation results indicate that, in addition to lower area requirement the proposed latch is more resistant to energetic particles strike than other similar latches and the rise and fall time of the proposed structure is between 12 to 15 ps in different conditions.

A meta-analysis on two microarray-based data was performed to identify the statistically enriched gene sets in Arabidopsis thaliana treated with nanoparticle (NPs) using Gene Set Enrichment Analysis (GSEA) based on Kyoto Encyclopedia of Genes and Genomes (KEGG). Log fold change (FC) of the gene expression under NPs treatment, compared to the control, was manually calculated in excel after data merging, to find gens with the highest expression under the treatment. GSEA analysis revealed that under NPs treatment, different pathways related to organ morphogenesis, cell adhesion molecule binding, epithelial development, immune response regulating signaling pathway, regulatory region nucleic acid binding, supramolecular complex, taxis (directed movement in response to stimulus), tube development, and vacuole were differentially expressed. Top 10 up-regulated genes under NPs treatment based on the Enrichment Score (ES) were AT1G69510, AT5G29000, AT3G17880, AT5G14590, AT5G57655, AT2G30530, AT1G55530, AT1G01770, AT2G17220, and AT2G25460. Many of these genes are involved in the response to stress and in the plant defense signaling.