Stability evaluation of ethanol dry reforming on Lanthania‐doped cobalt‐based catalysts for hydrogen‐rich syngas generation

Catalytic stability with time‐on‐stream is an important aspect in ethanol dry reforming (EDR) since catalysts could encounter undesirable deterioration arising from deposited carbon. This work examined the promotional effect of La on 10%Co/Al₂O₃ in terms of activity, stability, and characteristics. Catalysts were characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman, and X‐ray photoelectron spectroscopy (XPS) measurements whilst catalytic EDR performance of La‐promoted and unpromoted 10%Co/Al₂O₃ prepared via wet impregnation technique was investigated at 973 K for 72 h using a stoichiometric feed ratio (C₂H₅OH/CO₂ = 1/1). La promoter substantially enhanced both metal dispersion and metal surface area from 0.11% to 0.64% and 0.08 to 0.43 m² g^?1, respectively. Ethanol and CO₂ conversions appeared to be stable within 50 to 72 h after experiencing an initial activity drop. The conversion of C₂H₅OH and CO₂ for La‐promoted catalyst was about 1.65 and 1.34 times greater than unpromoted counterpart in this order. The carbonaceous deposition was considerably decreased from 55.6% to 36.8% with La promotion due to La₂O₂CO₃ intermediate formation. Additionally, 3%La‐10%Co/Al₂O₃ possessed greater oxygen vacancies acting as active sites for CO₂ adsorption and hence increasing carbon gasification. Even though graphitic and filamentous carbons were formed on used catalyst surface, La‐addition diminished graphite formation and increased the reactiveness of amorphous carbon.     

Infrared Study of Er(3+)/Yb(3+) Co-Doped GeO(2)-PbO-Bi(2)O(3) Glass

Heavy metal oxide glasses, containing bismuth and/or lead in their glass structure are new alternatives for rare eart (RE) doped hosts. Hence, the study of the structure of these vitreous systems is of great interest for science and technology. In this research work, GeO(2)-PbO-Bi(2)O(3) glass host doped with Er(3+)/Yb(3+) ions was synthesized by a conventional melt quenching method. The Fourier transform infrared (FTIR) results showed that PbO and Bi(2)O(3) participate with PbO(4) tetragonal pyramids and strongly distort BiO(6) octahedral units in the glass network, which subsequently act as modifiers in glass structure. These results also confirmed the existence of both four and six coordination of germanium oxide in glass matrix.     

Hydrothermal hydrolysis of starch with CO2 and detoxification of the hydrolysates with activated carbon for bio-hydrogen fermentation

The imminent use of hydrogen as an energy vector establishes the need for sustainable production technologies based on renewable resources. Starch is an abundant renewable resource suitable for bio-hydrogen generation. It was hypothesised that starch hydrolysates from a large (250 mL) hydrothermal reactor could support bioH₂ fermentation without inhibition by toxic byproducts.     

Electrical and optical properties of ZrxLa1−xOy nanocrystallites as an advanced dielectric for the next FET devices

In the present work, the spatial distribution of the leakage current through Zr_xLa_1?xO_y thin films with different degrees of crystallinity temperatures was investigated. Zr_xLa_1?xO_y nanocrystallites were prepared by sol–gel method, in that Zr atomic fractions in the combined is at the range of x = 5–60 %. The nanocrystallite’s phases and properties were characterized with using X-ray diffraction, fourier transfer infrared radiation, scanning electron microscopy, atomic force microscopy and transmission electron microscopy techniques. Electrical property characterization was also performed with cyclic-voltameter (C-V) technique in TRIS solution (pH = 7.3, with the formula (HOCH₂)₃CNH₂). C-V measurements showed current flow through the TRIS reduces at higher temperatures. Moreover, elemental qualitative analysis was performed with map and energy dispersive X-ray spectra confirmed above claims.     

Paddy Fields as Electrically Dense Media: Theoretical Modeling and Measurement Comparisons

Early models for paddy fields consist of a single-layered medium in which coherent effects within clusters of leaves are considered but multiple volume scattering is not. In this paper, the paddy canopy is modeled as a multilayered dense discrete random medium consisting of cylindrical and needle-shaped scatterers. Consideration is given to the coherent and near-field effects of the closely spaced scatterers through the Dense Medium Phase and Amplitude Correction Theory and Fresnel corrections, respectively, in the phase matrix. Then, this dense medium phase matrix is applied in the radiative transfer equations and solved up to the second order to consider double-volume scattering. Ground truth measurements of paddy fields were acquired at Sungai Burung, Selangor, Malaysia, for an entire season from the early vegetative stage of the plants to their reproductive stage. Measured parameters are used in the theoretical model to calculate the backscattering coefficients of paddy fields. Theoretical analysis of the simulation results shows in particular that second-order effects are important for cross-polarized backscatter data and that coherent effects need to be considered at lower frequencies. However, the use of needles to represent paddy leaves tends to underestimate the HH-polarized backscattering coefficients especially at the latter stages of plant growth, i.e., when the leaves are broader. The results are also used for comparisons with the backscattering coefficients obtained from RADARSAT images as well as that of earlier models to test the validity of the dense medium model with promising results.     

Effect of Global Warming on Intensity and Frequency Curves of Precipitation, Case Study of Northwestern Iran

Predicting natural phenomena like flood and drought and consequently presenting an appropriate solution for fighting such natural hazards in northwestern Iran is considered in this study through clustering the precipitation regime. To compare the reference period (past) with the simulated data, the statistics of daily precipitation in six stations of Ardebil, Ghazvin, Hamedan, Kermanshah, Sanandaj, and Tabriz, have been provided for a 30-year period (1961–1990) and compared with the simulated data of 2021–2050. The simulated data was generated by general atmosphere circulation model HADCM3, A1scenario and was downscaled using the LARS-WG model. The method for comparing precipitations was done based on clustering in the form of 5 clusters for all the stations and study periods. One of the results of this research is the greater concentration of precipitation for the cold periods of the year (winter and fall) and the increase of annual precipitation by the amount of 20.62 mm for future period. Furthermore, the normality of two coordinates of precipitation and cluster frequency percentage was evaluated. The outputs of this section demonstrate that the precipitations of cluster 3 which have the features of light rain with average intensity, fall on this normal line for most of the stations and study periods. On the other hand, precipitations of cluster 1 indicating very heavy and intense precipitations, have the most distance to the normal line in most cases. Therefore, the precipitations of the third cluster need optimal exploitation management while those of the first cluster need required risk and crisis management.     

Low-energy motion estimation architecture using quadrant-based multi-octagon (QBMO) algorithm

The H.264 video-coding standard is a great improvement on its predecessor in that it is able to save 50 % of the bit-rate while maintaining the same quality as MPEG-4. However, its high computational complexity means the standard consumes large amounts of energy to process a video sequence, especially during motion estimation (ME) searches. To overcome this problem, a low-energy ME architecture is proposed in this paper that utilizes a quadrant-based multi-octagon search algorithm as one of its fast-search motion-estimation techniques. The proposed architecture is able to reduce the clock cycle needed to perform the search by 42 % compared to the original conventional algorithm. This clock cycle reduction reduces energy consumption by up to 43 %.     

A triangular MIMO array antenna with a double negative metamaterial superstrate to enhance bandwidth and gain

Multiple‐input‐multiple‐output (MIMO) array antenna integrated with the double negative metamaterial superstrate is presented. The triangular metamaterial unit cell is designed by combining two triangular elements positioned in complementary on the same plane at different sizes. Such design with more gaps is used to excite rooms for more capacitance effects to shift the resonance frequency thus enlarging the bandwidth of the MIMO antenna. The unit cell is arranged in 7 × 7 periodic array created a superstrate metamaterial plane where the C_stray exists in parallel between the two consecutive cells. It is found that the existence of C_stray and gaps for each unit cells significantly influenced the bandwidth of the MIMO antenna. The higher value of the capacitance will lead to the negativity of permittivity. The superstrate plane is then located on top of the 4 × 2 MIMO with a gap of 5 mm. The integration resulted in improving the bandwidth to 12.45% (5.65‐6.4GHz) compared to only 3.49% bandwidth (5.91‐6.12GHz) of the MIMO antenna itself. Moreover, the negative permeability characteristic is created by a strong magnetic field between the complementary unit cells to have 14.05‐dBi peak gain. Besides that, the proposed antenna managed to minimize the mutual coupling and improve the mean effective gain, envelope correlation coefficient, and multiplexing efficiency.     

Mechanisms of Natural Extracts of Andrographis paniculata That Target Lipid-Dependent Cancer Pathways: A View from the Signaling Pathway

Andrographis paniculata is a local medicinal plant that is widely cultivated in Malaysia. It is comprised of numerous bioactive compounds that can be isolated using water, ethanol or methanol. Among these compounds, andrographolide has been found to be the major compound and it exhibits varieties of pharmacological activities, including anti-cancer properties, particularly in the lipid-dependent cancer pathway. Lipids act as crucial membrane-building elements, fuel for energy-demanding activities, signaling molecules, and regulators of several cellular functions. Studies have shown that alterations in lipid composition assist cancer cells in changing microenvironments. Thus, compounds that target the lipid pathway might serve as potential anti-cancer therapeutic agents. The purpose of this review is to provide an overview of the medicinal chemistry and pharmacology of A. paniculata and its active compounds in terms of anti-cancer activity, primary mechanism of action, and cellular targets, particularly in the lipid-dependent cancer pathway.