Asymmetric Fission Transmission of Linear-to-Circular Polarization Converter Using Bi-layer Split Ring Structure

A circular polarizer based on bi-layer split ring structure is proposed that could achieve asymmetric fission transmission of linearly polarized wave at the dual band. Firstly, a new approach of “Fission Transmission of Electromagnetic (FTEM) waves” is introduced to understand the polarization transformation behavior for linear-to-circular polarization. The designed structure achieves broadband circularly polarized wave with an asymmetric transmission over resonance frequencies by the principle of FTEM wave. The electronics circuit of proposed structure demonstrates the transformation behavior of EM waves when the electric and magnetic coupling between the upper and lower patterned SRR is reached at the certain strength. The physics of the giant circular dichroism effect and optical activity is illustrated by the surface currents distribution on the structure. The proposed structure achieves a right-handed circularly polarized wave and left hand circularly polarized wave with high transmission at 13.94–15.70 GHz and at 16.0–17.03 GHz, respectively. The axial ratio bandwidth of 11.76 and 6.86% is obtained at the dual band. The simulated and measured results exhibit good correspondence.     

A comparative study of full‐duplex relaying schemes for low latency applications

Various sectors are likely to carry a set of emerging applications while targeting a reliable communication with low latency transmission. To address this issue, upon a spectrally‐efficient transmission, this paper investigates the performance of a 1 full‐dulpex relay system and considers for that purpose, 2 basic relaying schemes, namely, the symbol‐by‐symbol transmission, i.e., amplify‐and‐forward and the block‐by‐block transmission, i.e., selective decode‐and‐forward. The conducted analysis presents an exhaustive comparison, covering both schemes, over 2 different transmission modes, i.e., the noncombining mode where the best link, direct, or relay link is decoded and the signals combining mode, where direct and relay links are combined at the receiver side. While targeting latency purpose as a necessity, simulations show a refined results of performed comparisons and reveal that amplify‐and‐forward relaying scheme is more adapted to combining mode, whereas the selective decode‐and‐forward relaying scheme is more suitable for noncombining mode.     

Synthesis of 2,4‐difuryl‐4H‐3,1‐benzothiazines via a furan ring migration reaction

A new simple synthetic approach to 2,4‐difuryl‐4H‐3,1‐benzothiazines from 2‐isothiocyanoaryldifuryl‐methanes in the presence of acidic catalyst is described. This rearrangement is a new example of furan ring migration reaction resulting from intramolecular attack with electrophilic carbon.     

Synthesis of the water-soluble [Rh(Tpms)(CO)(PTA)] compound, the first transition metal complex bearing the 1,3,5-triaza-7-phosphaadamantane (PTA) and the tris(1-pyrazolyl)methanesulfonate (Tpms) ligands

The water-soluble Rh^I compound [Rh(Tpms)(CO)(PTA)] (1) (Tpms = O₃SC(pz)₃⁻, PTA = 1,3,5-triaza-7-phosphaadamantane) has been easily prepared in high yield by a single-pot reaction of [{Rh(CO)₂(μ-Cl)}₂] with PTA and the tris(1-pyrazolyl)methanesulfonate lithium salt Li(Tpms), in a CH₂Cl₂/MeOH solution at room temperature. This synthetic strategy can be easily applied to the preparation of general [Rh(Tpms)(CO)(L)] (L = phosphine) complexes and constitutes a substantial improvement over the previously described procedures. Compound 1 is air stable in the solid state and water-soluble, affording stable solutions under an inert atmosphere. It has been characterized by IR, ¹H, ³¹P{¹H} and ¹³C{¹H} NMR spectroscopies, elemental and single crystal X-ray diffraction structural analyses. The solid state structure of 1 has a square-planar geometry with the Tpms ligand coordinating the metal centre in a (κ²: N,N) bipodal mode. The title compound has also been investigated by cyclic voltammetry in CH₃CN, and values of the E_L Lever and P_L Pickett electrochemical parameters (which measure the ligand net electron-donor character) are proposed for the PTA ligand. Complex 1 represents the first example of a transition metal complex bearing both PTA and Tpms (or any other tris(1-pyrazolyl)methane or derivative) ligands.     

MOFs for desulfurization of fuel oil: Recent advances and future insights

Nowadays, desulfurization of fuel oil has raised concern globally because of strict industrial and environmental legislations. Albeit hydrodesulfurization (HDS) has been extensively used in oil refineries to produce low sulfur oil (< 10 ppm) but not been proven as effective method for the removal of dibenzothiophene (DBT), benzothiophene (TH) and their derivatives. Subsequently, adsorptive desulfurization (ADS) and oxidative desulfurization (ODS) methods have been developed to achieve high removal efficiency. In the past decade, metal–organic frameworks (MOFs) and its composites as oxidative catalysts, as well as adsorbents, have attracted the researchers owing to high surface area, tunable properties, and reusable. The present review comprises use of MOFs and their composites for the removal of sulfur from fuel oil via ODS and ADS processes. Additionally, physicochemical properties of MOFs, mechanism, pros and cons of both process, regeneration, and future challenges have been discussed briefly. Moreover, current limitations and future prospective are also discussed.     

Comparison of contact angle measurement and microbial adhesion to solvents for assaying electron donor-electron acceptor (acid-base) properties of bacterial surface

The electron donor-electron acceptor (acid-base properties) of cell surfaces of a series of bacteria were determined by two methods, namely, Microbial Adhesion to Solvents (MATS) and Contact Angle Measurements (CAM) combined with equation of Van Oss. The efficiency of these two methods was then compared. Pseudomonas aeruginosa ATCC 27853, Bacillus subtilis ILP 142B, Staphylococcus aureus ATCC 25923 and four Escherichia coli strains including HB101, AL52, O128B12 and ATCC 25922, acid-base properties were examined under the two different conditions mentioned above. The results showed that the correlation between acid-base properties determined by MATS and CAM was very weak. We have also found that when the microbial cell surface was electron donor by CAM method, similar result was found by MATS, but the reverse was not always true. In contrast, a good correlation between the two methods was obtained when the four E. coli strains were examined.     

New Epoxydammarane Triterpenes from Salvia santolinifolia

Three new 20,24‐epoxydammarane triterpenes, santolins A–C ( 1 – 3 ), were isolated from the AcOEt‐soluble fraction of the MeOH extract of Salvia santolinifolia (whole plant). Their structures were assigned based on ¹H‐NMR, ¹³C‐NMR (DEPT), and 2D‐NMR analyses, in combination with HR‐MS experiments and comparison with literature data of related compounds.     

Two-step formation mechanism of<Emphasis Type="Italic"> Acetobacter</Emphasis> cellulosic biofilm: synthesis of sparse and compact cellulose

Classical studies concerning “Acetobacter xylinum” focus on bacterial cellulose “BC” yield and rate in broth, after a long period of incubation (7–14 days). Such observations do not highlight bacterial physiology in the first incubation hours and its impact on BC production. In this study, the growth of a wild strain of Acetobacter was monitored in the first incubation hours. We showed the presence of two different physiologies; the first extends from the incubation moment till the formation of a sparse BC. Sparse BC modifies surface viscosity, and stabilizes hydrodynamic conditions to initiate compact BC production that marks the second physiology. Two containers, of different shapes, were used to confirm our findings, one of which is a culture tube with high drift currents on the broth-air interface, and the other is a conical flask with more stable hydrodynamic conditions at the culture’s surface. We showed that Acetobacter always follows two physiologies independent of the container shape. Logistic model, FTIR, XRD and SEM analysis are used to confirm the results.     

An Optimal L∞–error Estimate for an Approximation of a Parabolic Variational Inequality

In this article, an optimal error estimate for parabolic variational inequalities is studied. Existence and uniqueness of the solution is provided by the introduction of a constructive algorithm. An optimally L^∞-asymptotic behavior in uniform norm is proved using the semi-implicit time scheme combined with the finite element spatial approximation. The approach is based on the concept of subsolutions.