Controllable hybrid plasmonic integrated circuit.

In this paper, a controllable hybrid plasmonic integrated circuit (CHPIC) composed of hybrid plasmonic waveguide (HPW)-based rhombic nano-antenna, polarization beam splitter, coupler, filter, and sensor has been designed and investigated for the first time. In order to control the power into a corresponding input port, a graphene-based 1 × 3 power splitter with switchable output has been exploited. The functionality of each device has been studied comprehensively based on the finite element method and the advantages over state-of-the-art have been compared. Moreover, the effect of connection of CHPIC to the photonic and plasmonic waveguides has been studied to exhibit the capability of variety excitation methods of the CHPIC. Furthermore, the performance of the proposed CHPIC connected to inter/intra wireless transmission links has been investigated. The wireless transmission link consists of two HPW-based nano-antennas as transmitter and receiver with the maximum gain and directivity of 10 dB and 10.2 dBi, respectively, at 193.5 THz. The suggested CHPIC can be used for applications such as optical wireless communication and inter/intra-chip optical interconnects.

Theoretical analysis of a circular hybrid plasmonic waveguide to design a hybrid plasmonic nano-antenna.

In this paper, a circular hybrid plasmonic waveguide-fed nano-antenna (CHPWFNA) has been introduced for operating at the standard telecommunication wavelength of 1,550 nm. For the first time, the dispersion relation of a circular hybrid plasmonic waveguide as the feed line of the proposed nano-antenna has been derived, analytically. To verify the accuracy of the analytical solution, two numerical techniques of finite element method (FEM) and finite-difference time-domain (FDTD) method have been used. Numerical results are well-matched with the theoretical ones. The characteristics of the CHPWFNA have been studied by two mentioned methods. The obtained realized gains (directivities) by the FDTD and FEM simulations are 9.03 dB (9.38 dBi) and 10.00 dB (10.32 dBi), respectively, at 1,550 nm wavelength. For on-chip point-to-point wireless link performance, the obtained quality factor by the FDTD method (FEM) is 63.97 (100). The obtained radiation characteristics and link performance reveal that at 1,550 nm, the proposed antenna has the best performance. Besides, the frequency bandwidth of the antenna (185-200 THz) covers the low-loss optical frequency range. Also, paying attention to the laser eye safety is so important. Consequently, the wavelength of 1,550 nm has been chosen as the target wavelength. Moreover, the array configuration has been studied and the directivity and realized gain have been obtained based on the array factor theory and numerical methods, which are agree with each other. The attained realized gain by the FDTD method (FEM) for the considered single row array, at 1,550 nm, is 11.20 dB (11.30 dB). There is a little difference between the numerical results due to the total mesh size, the grid size refinement and the relative error of the numerical methods convergence. Finally, as one of the most important challenges in fabrication is the gold surface quality, we have studied the effect of gold surface roughness and its pentagonal cross section on the antenna performance.

Theoretical analysis of ultra-fast multi-wavelength switch containing Kerr nonlinear material and its application as simultaneous AND and NOR logic gates.

In this paper, an all-optical plasmonic multi-wavelength switch based on Kerr nonlinear material is proposed. It consists of circular waveguides wrapped around three side-coupled nano-ring resonators. Fundamentally, introducing the circular waveguide increases the coupling coefficient and switching modulation depth. The transmission response of the proposed multi-switching structure is studied theoretically based on coupled mode and transfer matrix theories. The validity of the derived transmission formula is confirmed by the numerical result obtained by the finite element method. Also, based on the self-phase modulation and cross-phase modulation (XPM) nonlinear effects, the resonance wavelengths are effortlessly tuned by changing the intensity of the incident lightwave without changing the dimensions of the structure. As a result, by utilizing the XPM effect, the required input signal intensity is significantly decreased to 6.5MW/cm2. The obtained modulation depths are 18.08, 31.83, and 28.40 dB at wavelengths of 850, 1310, and 1550 nm, respectively. Finally, to show the application of the proposed switch, the simultaneous AND and NOR logic gates are designed with intensity contrast ratios of 78.81 and 85.49 dB, respectively. The proposed plasmonic switch has many advantages such as being multi-wavelength and having low required switching intensity, ultra-fast switching time of 23 fs, and optical bistability. These features are promising for future integrated plasmonic devices for applications such as communications, signal processing, and sensing.

Photocatalytic degradation of penicillin G from simulated wastewater using the UV/ZnO process: isotherm and kinetic study.

PURPOSE: Pharmaceutical contaminants, including antibiotics, present in the environment, especially water resources, are a main concern for human and environmental health due to their stability and non-degradability. Accordingly, the purpose of this study was to investigate the photocatalytic removal of penicillin G antibiotic from simulated wastewater using a photocatalytic process [UV/ZnO] in an isotherm and kinetic study. METHODS: In the current research, the ZnO nanoparticles [ZnO NPs] were initially characterized by scanning electron microscope [SEM] and X-ray diffraction [XRD]. Then, its efficiency was investigated in the photocatalytic degradation process of penicillin G. The evaluated parameters in the adsorption process penicillin G antibiotic were pH [1-5], penicillin G concentration [10-30 mgL-1], NP dosage [0.5-4.5 gL-1] and contact time [5 to 200 min]. Then, the effect of pH [3, 5, 7, 9, 11, and], penicillin G concentration [10-30 mgL-1], NP dosage [0.01-1.5 gL-1] and contact time [5 to 200 min] in the photocatalytic degradation (UV/ZnO) was studied. The residual penicillin G concentration was measured using a spectrophotometery at a wavelength of 283 nm. RESULTS: The results indicated that the penicillin G removal efficiency of photocatalytic process [UV/ZnO] using ZnO was 74.65% at the concentration of 10 mgL-1, the pH value of 5, the ZnO NP dosage of 0.1 gL-1 and the contact time of 180 min, as well as the kinetics of degradation followed the pseudo-first-order kinetic model. CONCLUSION: It can be concluded that the use of this process is appropriate an effective for the removal of the antibiotic pollutants.

Correction to: Photocatalytic degradation of penicillin G from simulated wastewater using the UV/ZnO process: isotherm and kinetic study.

[This corrects the article DOI: 10.1007/s40201-020-00442-7.].

Analytic approach to study a hybrid plasmonic waveguide-fed and numerically design a nano-antenna based on the new director.

In this paper, a wideband InP-based hybrid plasmonic nano-antenna (HPNA) operating at telecommunication wavelengths has been proposed. Monolithically integrating InP-based lasers with hybrid plasmonic waveguide (HPW) as a feed line of the proposed HPNA on the same InGaAsP/InP wafer can increase the antenna efficiency. A new vertical director has been employed to have a highly directive horizontal radiation pattern. This enhancement is attributed to the efficient coupling between the radiation patterns of arm elements as well as reduced side lobes and back-lobes levels due to the achieved impedance matching. As a result, the directivity has been increased considerably, 3.6 dBi at 193.5 THz (1550 nm) and 1.1 dBi at 229 THz (1310 nm). The HPNA shows the high directivity, total efficiency and quality factor of 11.8, 97.49% and 94.57, respectively. Further, to verify the validity of confining the fundamental TM mode to a thin layer with the lower refractive index, both theoretical and numerical methods have been employed. Therefore, we have derived an analytical formula to investigate the HPW dispersion relation based on the transfer matrix theory and genetic algorithm. Moreover, due to the HPNA ability to receive an optical signal from free space and transmit it to the waveguide based on the reciprocity theorem, the HPNA performance as an optical wireless on-chip nano-link has been investigated analytically and numerically. Additionally, to obtain a high optical power signal and steering the beam angle, the antenna gain and directivity have been calculated with two different types of array structure by controlling the relative phase shift between the array elements and elements number. To validate the array design performance, a three dimensional full-wave numerical simulation and array factor theory have been exploited. The HPNA fabrication is compatible with generic foundry technology.

The practical utility of the synthesis FeNi3@SiO2@TiO2 magnetic nanoparticles as an efficient photocatalyst for the humic acid degradation.

Humic acid (HA) compounds in drinking water and wastewater disinfection processes are viewed as precursors of highly toxic, carcinogenic, and mutagenic disinfection by-product chemicals. In recent times, these compounds have gained considerable attention of scientists for their successful removal from aqueous solutions to permissible limits. To achieve this aim, the present study investigated, for the first time, the photocatalytical performance of the synthesis FeNi3@SiO2@TiO2 nanoparticles for the HA degradation under different environmental conditions. The photocatalytic reactions were performed using ultraviolet (UV) radiation, whose intensity was fixed at 2500 µW/cm2 throughout the experimental study. The characterization study performed, using specific diagnostic techniques, revealed the presence of several good morphological, magnetic, and catalytic specifications of the synthesized nanoparticles. The use of the simplified form of the Langmuir-Hinshelwood equation sufficiently describes the experimental data of the HA kinetic degradation, as it shows a high coefficient of regression values. Furthermore, the complete HA degradation was reached under conditions of pH = 3; initial HA concentration = 10 mg/L; FeNi3@SiO2@TiO2 nanoparticles dosage = 0.01 g/L; and reaction time >30 min. Thus, the results obtained from this research suggested that the catalyst of FeNi3@SiO2@TiO2 nanoparticles was an attractive, novel, and effective agent, which could be used for the degradation of HA in the photocatalytic processes.

Synthesis and characteristics of a novel FeNi3/SiO2/TiO2 magnetic nanocomposites and its application in adsorption of humic acid from simulated wastewater: study of isotherms and kinetics.

The presence of natural organic matter such as humic acid in water creates various problems in water purification. Humic acid can react with chlorine in the disinfection step and lead to the production of trihalomethanes and haloacetic acids that these compounds have carcinogenic and mutagenic properties; therefore, they must be removed before arriving to the disinfection stage. The purpose of this research was adsorption of humic acid from simulated wastewater by synthesized FeNi3/SiO2/TiO2 magnetic nanocomposites. FeNi3/SiO2/TiO2 magnetic nanocomposites were synthesized by sol-gel procedure and its characteristics were determined by TEM, VSM, BET, FESEM, and XRD techniques. Then, the effects of such pH (3-11), FeNi3/SiO2/TiO2 dosage (0.005-0.1 g/L), contact time (0-200 min), and initial concentration (2-15 mg/L) were studied on humic acid adsorption using FeNi3/SiO2/TiO2. The results of adsorption experiments revealed that the highest percentage of humic acid removal (94.4%) was achieved at pH 3, initial concentration of 5 ppm, FeNi3/SiO2/TiO2 dose of 0.1 g/L, and contact time of 90 min. The analyses of experimental isotherm data showed that the humic acid adsorption was described by Langmuir model and also the kinetic studies represented that the process of adsorption of humic acid on FeNi3/SiO2/TiO2 was followed by the pseudo-second kinetic. According to the results, it can be concluded that FeNi3/SiO2/TiO2 magnetic nanocomposites have a high ability to absorb humic acid from simulated wastewater.

A comparative study of using barberry stem powder and ash as adsorbents for adsorption of humic acid.

In the present research, investigation of the practical utility of barberry stem powder (BSP) and barberry stem ash (BSA) for humic acid (HA) removal from an aqueous medium by adsorption was carried out. The adsorption process was tested by varying of pH (3-11), reaction time (5-20 min), initial HA concentration (5-40 mg/L), adsorbent dosage (1-4 g/L), and temperature (15-35 °C). The isothermal results revealed that the adsorption process is favorable for both used adsorbents and it is highly described using the Freundlich and Langmuir models (R2 > 0.960). Also, the maximum uptakes of BSP and BSA for HA were 20.220 and 16.950 mg/g at the abovementioned optimized conditions (pH = 7, reaction time = 10 min, temperature = 15 °C, initial HA concentration = 40 mg/L, and adsorbent amount = 1.0 g/L), respectively. The results achieved from the fitting of the experimental data with Dubinin-Radushkevich isotherm model showed that the HA molecules are adsorbed onto the BSP and BSA by physiosorption process. From the thermodynamic study, it appeared that the biosorption process of the HA onto two studied adsorbents was of exothermic nature. The kinetics of the adsorption process of HA has been found to be pseudo-second-order model (R2 = 0.930-0.999). Thus, the results obtained from this paper elucidated that the BSP exhibited higher adsorption capacity in comparison to BSA, for HA removal up to permissible concentrations.

The effect of nutrition and food hygieneeducation on the knowledge of female elementary school teachers in city of ferdows.

INTRODUCTION: Teachers are one of the most influential groups in elevating social health, and their teaching nutritional points to the students can both affect students' awareness and the transferring of such nutritional education to the families. This study was undertaken tosurvey the influence of nutrition and nutritional health education on the awareness of female elementary school teachers. MATERIALS AND METHODS: Fifty-seven female elementary school teachers were chosen from the Ferdows City for this quasi-experimental study. Prior to the outset of the educational workshop, they were asked to fill out a questionnaire about nutrition and nutritional health, which was followed by the two-day workshop. After two months, they were given a second questionnaire. The results were analyzed by paired t-test, ANOVA, and McNemar. In all the tests, a significance level α = 0.05 was considered. RESULTS: Findings of the study showed that the mean score of awareness before interference was 10.98%, which reached up to 18.2% after the interference (P < 0.001). With regard to theimportance of breakfast intake, the teachers' awareness increased from 57.9 to 98.2% from before to after intervention, respectively. CONCLUSION: Applying interventional methods of education in teacher training centers in conjunction with medical and educational centers, with regard to nutrition and nutritional health, can elevate the health of students.

Properties of Geobacillus stearothermophilus levansucrase as potential biocatalyst for the synthesis of levan and fructooligosaccharides.

The production of levansucrase (LS) by thermophilic Geobacillus stearothermophilus was investigated. LS production was more effective in the presence of sucrose (1%, w/v) than fructose, glucose, glycerol or raffinose. The results (Top 57°C; stable for 6 h at 47°C) indicate the high stability of the transfructosylation activity of G. stearothermophilus LS as compared with LSs from other microbial sources. Contrary to temperature, the pH had a significant effect on the selectivity of G. stearothermophilus LS-catalyzed reaction, favoring the transfructosylation reaction in the pH range of 6.0-6.5. The kinetic parameter study revealed that the catalytic efficiency of transfructosylation activity was higher as compared with the hydrolytic one. In addition to levan, G. stearothermophilus LS synthesized fructooligosaccharides in the presence of sucrose as the sole substrate. The results also demonstrated the wide acceptor specificity of G. stearothermophilus LS with maltose being the best fructosyl acceptor. This study is the first on the catalytic properties and the acceptor specificity of LS from G. stearothermophilus.

Effect of lithium chloride on the luteal steroidogenesis in gonadotropin-stimulated rat.

BACKGROUND: Main function of corpus luteum is progesterone synthesis that is significantly accompanied with an increase in levels of mRNA encoding of steroidogenic enzymes known as luteal markers. OBJECTIVE: This study was designed to evaluate effects of lithium chloride on the release of steroid hormones and steroidogenic enzymes in gonadotropin-stimulated rats. MATERIALS AND METHODS: Immature 23 days old Wistar rats were divided into 10 groups; each group comprised of 8 rats, and induced with single injection of pregnant mare's serum gonadotrophin (PMSG) and followed by single injection of human chorionic gonadotropin (hCG). Then, rats were given lithium chloride (LiCl) or saline at 12 hours post-hCG injection. Ovaries were collected in 4-hour interval from 8-24 hour post-hCG injection. Expression pattern of steroidogenic acute regulatory protein (StAR), side-chain cleavage cytochrome P450 (P450scc) and 3ß-hydroxysteroid dehydrogenase (3ß-HSD) genes were determined by semi-quantitative RT-PCR. In addition, serum levels of progesterone and 17ß-estradiol were measured by ELISA. RESULTS: Our results showed that hCG stimulation of progesterone was markedly diminished and transcript levels of key steroidogenic enzymes were altered in the hormone-stimulated rats following LiCl treatment. CONCLUSION: These results suggest that critical steps in the function of corpus luteum are disrupted by lithium. It is concluded that LiCl is an effective factor for suppressing of steroid genes expression.