Kinetics of para-nitrophenol and chemical oxygen demand removal from synthetic wastewater in an anaerobic migrating blanket reactor

A laboratory scale anaerobic migrating blanket reactor (AMBR) was operated at different HRTs (1-10.38 days) in order to determine the para-nitrophenol (p-NP) and COD removal kinetic constants. The reactor was fed with 40 mg L(-1)p-NP and 3000 mg L(-1) glucose-COD. Modified Stover-Kincannon and Grau second-order kinetic models were applied to the experimental data. The predicted p-NP and COD concentrations were calculated using the kinetic constants. It was found that these data were in better agreement with the observed ones in the modified Stover-Kincannon compared to Grau second-order model. The kinetic constants calculated according to Stover-Kincannon model are as follows: the saturation value constant (K(B)) and maximum utilization rate constants (R(max)) were found as 31.55 g CODL(-1)day(-1), 29.49 g CODL(-1)day(-1) for COD removal and 0.428 g p-NPL(-1)day(-1), 0.407 g p-NPL(-1)day(-1) for p-NP removal, respectively (R(2)=1). The values of (a) and (b) were found to be 0.096 day and 1.071 (dimensionless) with high correlation coefficients of R(2)=0.85 for COD removal. Kinetic constants for specific gas production rate were evaluated using modified Stover-Kincannon, Van der Meer and Heerrtjes and Chen and Hasminoto models. It was shown that Stover-Kincannon model is more appropriate for calculating the effluent COD, p-NP concentrations in AMBR compared to the other models. The maximum specific biogas production rate, G(max), and proportionality constant, G(B), were found to be 1666.7 mL L(-1) day(-1) and 2.83 (dimensionless), respectively in modified Stover-Kincannon gas model. The bacteria had low Haldane inhibition constants (K(ID)=14 and 23 mg L(-1)) for p-NP concentrations higher than 40 mg L(-1) while the half velocity constant (K(s)) increased from 10 to 60 and 118 mg L(-1) with increasing p-NP concentrations from 40 to 85 and 125 mg L(-1).     

End product rejection rate and its correlation with melt treatment in direct-chill casted hot rolling slabs

In this study, different melt treatment operations were evaluated and compared to end product’s scrap rate using bifilm index (B_I) method. Results clearly show that degassing with finer gas bubbles increases cleaning performance for the removal of any type of bifilms in the melt. B_I method is a reliable and quick way to determine melt quality at any given time during casting process which is found to have a direct correlation with rejection rate.     

Detection of bacillus Calmette-Guerin in the blood by the polymerase chain reaction method of treated bladder cancer patients

PURPOSE: Following intravesical bacillus Calmette-Guerin (BCG) instillation, we attempted to detect BCG in the blood using the polymerase chain reaction (PCR) method and correlate these findings with the occurrence of major complications due to this treatment. MATERIALS AND METHODS: Intravesical BCG immunotherapy was given to 22 consecutive patients with superficial bladder tumors. In 2 patients the BCG instillation had to be discontinued due to serious side effects of therapy. Blood samples (252 aliquots) were obtained from 126 BCG courses in 22 cases, and 2 additional samples (4 aliquots) were obtained from 1 patient 1 and 3 months after cessation of therapy. All blood samples were analyzed by the PCR technique for detection of deoxyribonucleic acid tuberculosis Mycobacterium tuberculosis. RESULTS: Of the 126 blood samples 9 (7.1%) were PCR positive for M. tuberculosis. These 9 positive samples belonged to 3 patients, all of whom were among those 4 patients who had major clinical side effects. CONCLUSIONS: We demonstrated that rapid and sensitive detection of mycobacteremia by PCR correlated with the clinical course of these patients. We also demonstrated that PCR can be used to monitor BCG in the blood after antituberculous therapy. The early, fast and accurate diagnosis of BCG in the blood by PCR may alter the serious clinical course of these patients by initiation of specific treatment early. However, further extensive studies are needed to validate these results.     

Power allocation and temporal fair user group scheduling for downlink NOMA

Non-Orthogonal Multiple Access (NOMA) has been proposed as a new radio access technique for cellular networks as an alternative to OMA (Orthogonal Multiple Access) in which the users of a group (pairs or triples of users in a group are considered in this paper) are allowed to use the wireless channel simultaneously. In this paper, for downlink single-input single-output SISO-NOMA, a heuristic power allocation algorithm within a group is first proposed which attempts to ensure that the users of a group benefit from simultaneous transmission equally in terms of achievable throughput. Moreover, a user group scheduling algorithm is proposed for downlink NOMA systems by which a user group is to be dynamically selected for transmission while satisfying long term temporal fairness among the individual contending users. The effectiveness of the proposed power allocation method along with the temporal fair scheduling algorithm for downlink NOMA is validated with simulations and the performance impact of the transmit power and the coverage radius of the base station as well as the number of users are thoroughly studied.

     

Design of wideband microstrip power divider/combiner with input and output impedance matching for RF energy harvesting applications

Lately, it has been seen that wireless communication systems have been more developed and there has been a huge demand for multi‐spectral transactions. Using circuits for more than one function is a serious requirement in communication technology. Especially, it expected from RF output stages to show the same performance on more than one frequency. To that end, it is required to produce a solution with wideband designs. In this study, a novel power divider/combiner design with a layered conic line has been investigated for the RF energy harvesting applications. The center frequency was set at 2 GHz and concluded with three different designs. In each design, bandwidth and S parameter characteristics were compared according to the number of layers of the transmission, and it was observed that as the number of layers increases, the bandwidth also increases. According to the design result, triple layer Wilkinson power divider was selected to connect to Villard voltage doubler circuit. The Wilkinson power combiner circuit inputs were given between ?10 dBm and 5 dBm input power. As a result, when low input power was given, efficiency was observed about 70%.     

Synthesis and characterization of 2‐hydroxyethylmethacrylate/2‐(3‐indol‐yl)ethylmethacrylamide‐based novel hydrogels as drug carrier with in vitro antibacterial properties

In this study, a new cationic monomer 2‐(3‐indol‐yl)ethylmethacrylamide (IEMA) derived from tryptamine was synthesized in a single step and characterized by Fourier transform infrared (FTIR), ¹H‐NMR, and ¹³C‐NMR. Then, one‐step preparation of novel poly[2‐hydroxyethylmethacrylate‐c‐2‐(3‐indol‐yl)ethylmethacrylamide], or p(HEMA‐c‐IEMA), copolymeric hydrogels has been performed successfully with IEMA and 2‐hydroxyethylmethacrylate (HEMA) as monomers using free radical aqueous polymerization. The hydrogels were characterized with scanning electron microscopy, FTIR, elemental analysis, thermogravimetric analysis, and texture profile analysis instruments. p(HEMA‐c‐IEMA) hydrogels were used for swelling, diffusion, drug release, and antibacterial activity studies. The drug‐release behavior of the hydrogels was determined as a function of time at 37 °C in pH 1.2 and 7.2. The swelling and drug‐release studies showed that an increased IEMA amount caused a higher increase in swelling and drug‐release values. Additionally, zero‐order, first‐order, and Higuchi equation kinetic models were applied to the drug‐release data, and the data fit well in the Higuchi model, and the Peppas power‐law model was applied to the release mechanism. Finally, the antibacterial activities of the hydrogels were screened against Gram‐positive bacteria (Bacillus cereus and Staphylococcus aureus) and Gram‐negative bacteria (Escherichia coli and Salmonella typhimurium). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45550.     

A coordinate transformation approach for efficient repeated solution of Helmholtz equation pertaining to obstacle scattering by shape deformations

A computational model is developed for efficient solutions of electromagnetic scattering from obstacles having random surface deformations or irregularities (such as roughness or randomly-positioned bump on the surface), by combining the Monte Carlo method with the principles of transformation electromagnetics in the context of finite element method. In conventional implementation of the Monte Carlo technique in such problems, a set of random rough surfaces is defined from a given probability distribution; a mesh is generated anew for each surface realization; and the problem is solved for each surface. Hence, this repeated mesh generation process places a heavy burden on CPU time. In the proposed approach, a single mesh is created assuming smooth surface, and a transformation medium is designed on the smooth surface of the object. Constitutive parameters of the medium are obtained by the coordinate transformation technique combined with the form-invariance property of Maxwell’s equations. At each surface realization, only the material parameters are modified according to the geometry of the deformed surface, thereby avoiding repeated mesh generation process. In this way, a simple, single and uniform mesh is employed; and CPU time is reduced to a great extent. The technique is demonstrated via various finite element simulations for the solution of two-dimensional, Helmholtz-type and transverse magnetic scattering problems.     

Thermodynamic interactions of a copolyester of bisphenol A with terephthalic acid and isophthalic acid with some solvents

The retention diagrams of n‐octane, n‐nonane, n‐decane, n‐butyl acetate, isobutyl acetate, and isoamyl acetate on the polyarylate Ardel D‐100, a copolyester of bisphenol A with terephthalic acid and isophthalic acid, were plotted at temperatures between 120 and 260°C by an inverse gas chromatography technique. The glass‐transition temperature of the copolymer was determined to be 190°C from the discontinuity of these diagrams. The retention diagrams of benzene, ethyl benzene, n‐propyl benzene, isopropyl benzene, and chlorobenzene were also plotted between 200 and 260°C. The specific retention volume, weight fraction activity coefficient, Flory–Huggins polymer–solvent interaction parameter, hard‐core polymer–solvent interaction parameter, and effective exchange energy parameter were determined for the studied solvents. The parameters suggest that the studied aromatic hydrocarbons and aliphatic esters are moderately good solvents and chlorobenzene is a very good solvent for this copolyester, but the n‐alkanes are very poor solvents. The solubility parameter of this copolymer was determined to be 11.6 (cal/cm³)^1/2 at room temperature by extrapolation of the values of the solubility parameters from the studied temperatures to 25°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2365–2368, 2005     

Synthesis,characterization and cytotoxicity of novel modified poly[(maleic anhydride)‐ co‐(vinyl acetate)]/noradrenaline conjugate

Poly[(maleic anhydride)‐co‐(vinyl acetate)] (MAVA) copolymer was synthesized by free radical polymerization reaction, in methyl ethyl ketone at 80 °C, using benzoyl peroxide as the initiator. The copolymer was then modified with a biomolecule, noradrenaline (NA). The modification reaction was performed at 70 °C in dimethylformamide containing triethylamine as the catalyst. The modified polymer was named MAVA/NA. Structural characterization of the copolymer and the modified product was carried out by Fourier transform infrared (FTIR) and ¹H NMR and ¹³C NMR spectroscopy. The FTIR, ¹H NMR and ¹³C NMR spectra confirmed that NA was successfully covalently bound to the MAVA copolymer backbone. Surface morphology was visualized by atomic force microscopy. The cumulative release of NA from MAVA/NA was determined in phosphate buffered saline solution for 7 days at 37 °C and compared with MAVA. Cytotoxicity of the MAVA/NA was evaluated by using a mouse fibroblast cell line (L929). Results obtained indicated that MAVA/NA had almost no toxicity and no negative effect on cell viability at 250 µg mL^?1 concentration. © 2012 Society of Chemical Industry