This study aims to improve bacterial laccase enzyme activity (LEA) and dehydrogenase activity (DHA) affecting acetylsalicylic acid (ASA) biodegradation using an alternating current (AC). A microbial ...consortium was inoculated in an electroactive bioreactor supplied with an AC by a function generator under operating conditions of amplitude (AMPL) = 2–10 peak-to-peak voltage (
V
pp
), optical fiber splice tray (OFST) = 0.1 V, and sine wave frequency = 10 Hz. The obtained results revealed that at an applied voltage of 8
V
pp
and an OFST of 0.1 for 12 h, the maximum bacterial LEA and DHA were 30.6 U/mL and 75.5 micro grTF/cm
2
.gr biomass; respectively. Cell viability and permeability were equal to 95.7% and 0.3%; respectively, at the voltage of 8
V
pp
. Moreover, liquid chromatography–mass spectrometry (LC-MS) and gas chromatography–mass spectrometry (GC-MS) analyses showed that by-products had lower intensity at 8
V
pp
compared with that of 2
V
pp
voltage. Finally, the results demonstrated an optimum applied voltage of the AC, which could stimulate and promote bacterial LEA and DHA. Therefore, an electroactive bioreactor supplied with an AC can be a novel system for stimulation of enzyme activities in the process of ASA biodegradation.
In this study, a mixture of nano-encapsulated phase change materials in water has been used as the working fluid in a pulsating heat pipe in order to investigate its thermal performance. The results ...of the experiments showed that using the nano-encapsulated paraffin dispersed in water as working fluid improves heat transfer and decreases the thermal resistance of the pulsating heat pipe. On the other hand, among the tested concentrations for nano-encapsulated paraffin, there is an optimal value in which increasing the concentration causes an increase in the thermal resistance of the pulsating heat pipe due to the increased dynamic viscosity of the fluid. Enhancement in the thermal performance of the pulsating heat pipe by adding paraffin nanocapsules is attributed to the increase in effective specific heat of the fluid mixture as a result of the latent heat of paraffin nanocapsules. Higher effective sensible heat leads to an augmentation of convective heat transfer which has the main role in heat transfer of heat pipes. Moreover, the existence of nano-encapsulated paraffin can result in more mixing which is another reason for heat transfer enhancement. In addition, the use of nano-encapsulated phase change paraffin at high concentrations causes a cessation in the dry-out phenomenon at higher heat input compared with water or, in other words, increases the operating range of the pulsating heat pipe, which is due to an increase in the heat capacity of the fluid. In addition, the effect of inclination angle (30°, 60°, and 90°) on the thermal performance of the PHP at an optimum concentration among tested concentrations of nano-encapsulated paraffin was investigated, which was equal to 6.25 g L
−1
. It was observed that the PHP had its best thermal performance at the vertical position. The lowest measured thermal resistance of the PHP was 0.86 K W
−1
in a vertical orientation and 50 W heat input. Moreover, at 30°, the thermal resistance of the PHP sharply increased, which can be attributed to the reduced effect of gravity in fluid return from the condenser to the evaporator. The maximum thermal resistance of the PHP observed in the case of inclination angle equal to 30° and 10 W heat input was 5.38 K W
−1
.
We report a membrane that can be reversibly switched between a hydrophilic state and a hydrophobic state simply by alternately bubbling CO2 into and passing electric potential (EP) through a solution ...in contact with the membrane. The prepared membrane could be effectively used for oil/water separation.
The present study considers the impact of the alternating electric current on the viability and biological activity of denitrifying bacteria in a microbial electrochemical system (MES). The ...bio-stimulation using low-frequency low-voltage alternating current (AC) was studied in terms of the adenosine triphosphate (ATP) level of bacteria, viability, morphological characteristics, cell size, and complexity. Apoptosis assays by flow cytometry revealed that 81–95% of the cells were non-apoptotic, and cell membrane damage occurred < 18%. The applied AC could affect the bacterial metabolic activity and ATP content in the denitrifying bacteria depending on characteristics of the alternating electric current. Scanning electron microscopy (SEM) analysis of cell morphology illustrated low cell deformations under AC stimulation. The obtained results revealed that the applied alternating electrical current could increase the metabolic activity of denitrifying bacteria, leading to a better denitrification.
Graphical abstract
ᅟ
Polystyrene latexes where the stabilizing moiety originated from I) the inistab (initiator + stabilizer), 4,4'- Azobis(4-cyanopentanoic acid) (ACPA), II) acrylic acid (AA) (in situ copolymerized) ...or/and III) previously synthesized poly(acrylic acid)-
block
-polystyrene (PAA-
b
-PS) were prepared via surfactant-free emulsion polymerization (SFEP). This attitude of incorporating the sodium carboxilate groups (COO
−
Na
+
) as negatively charged stabilizing moieties in different materials yield quite different nucleation mechanism. Therefore, the different particle size would be expected. The average size of latex particles were ranged from 1.3 micron to 50 nm. Using ACPA as the only stabilizer produced latexes that were ranged from 200 nm to 1.3 micron. In contrast, when the stabilizing moieties originated from PAA-
b
-PS, the latexes exhibited the size below the 100 nm. By combining the use of both in situ polymerized ACPA inistab, AA monomer with/without PAA-
b
-PS, we were able to produce latexes with tunable polystyrene particle sizes.
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•Combined ultrasound and micro aerobic pretreatment for sewage sludge solubilization was assessed.•Low-strength ultrasonic enhanced lipase enzyme activities.•Micro-aerobic ...pretreatment led to solubilization and increased microbial activity in sewage sludge.•Combined ultrasonic and micro-aeration pre-treatment improved the bio-methane production by 193%.•Combined pretreatment increased energy recovery from anaerobic digestion sewage sludge up to 55%.
Low-frequency ultrasonics is a potential technology to reduce the hydrolysis phase period in anaerobic digestion process. In this study, theinfluence of combined low frequency ultrasonics and micro-aerobic (MA) pretreatment on sewage sludge solubilization, enzyme activity and anaerobic digestion were assessed. Initially, the effect of ultrasonic density (0.012, 0.014, 0.016, 0.018, 0.1, 0.12 and 0.14 W/mL) and irradiation time (1, 3, 5, 8, 9, 10 and 12 min) of 20 kHz frequency waves were investigated. Accordingly, the effect of micro-aerobic pretreatment (Air flow rate (AFR) = 0.1, 0.2, 0.3 and 0.5 VVM) within 20, 30, 40.48 and 60 h were examined. In addition, the effect of combined pretreatment on COD solubilization, lipase enzyme activation, ATP, percentage of live bacteria and methane gas production during the anaerobic process were examined. The results showed that the highest lipase activity (14.9 Umol/mL) was obtained under the effect of ultrasonic density of 0.1 W/ml within 9 min. The highest solubilization (65%) was observed under optimal micro-aerobic conditions: AFR = 0.2 (VVM) and micro-aerobic time: 40 h. Combined ultrasonic and micro-aerobic (US + MA) pretreatment increases the solubilization (70%), microbial activity (2080%) and lipase enzymatic activity (129%) compared to individual pretreatment. The Biogas production during anaerobic digestion pretreated with combined methods increased by 193% compared to the control, while the elevated values of biogas production in reactors pretreated by ultrasonic and micro-aerobic pretreatment alone were observed to be 101% and 165%, respectively. The net energy in reactor with the combined pre-treatment methods was calculated to be 1.26 kWh, while this value for control, pretreated ultrasonic and micro-aerobic reactors were obtained to be 0.56, 0.67 and 1.2 kWh, respectively.
While there has been a plethora of inquiries into reported speech, a cross-linguistic analysis of the source segments in political news reports is still a rarity. This study aims at a three-fold ...investigation: first, tracking the frequency, transparency, and types of the sources; second, identifying the strategies employed to introduce these sources in text, and third, interrogating the contextual elements. To this end, a bottom-up analysis of 120 news reports from four quality newspapers (Kayhan and Jomhouri-e Eslami from Iran and The New York Times and The Wall Street Journal from the U.S.), mainly informed by van Leeuwens (1996) model of social actors, was carried out. The findings suggest a heavy reliance of both sets of newspapers on external sources to fulfill their vested interests, although they varied significantly with respect to frequency, transparency, and type.
Wireless Sensor Network has been widely used in a variety of applications such as; medical, agriculture, military, monitoring environment and so on. In healthcare wireless sensor networks, sensors ...which are placed on specific parts of the patient’s body, detect patient’s vital signs and transmit them to a medical center. As a matter of fact, too many of these sensors begin to simultaneously send the information congestion which is likely to happen in a network. In other words, when the sensors on the patient’s body are constantly sending data packets, the congestion is more likely to happen. This could result in an increase of packet loss ratio and thus efficiency decreases and it affects the overall performance of the system, In this regard, so the congestion control is a major challenge. Congestion detection and control are essential for such systems. In this protocol a new active queue management method is proposed to determine packet loss probability. The proposed AQM integrates the random early detection and fuzzy proportional integral derivative (FuzzyPID) controller methods together. When fuzzy logic combines with PID, it helps to control the target buffer queue. A fuzzy logical controller also estimates and adjusts the sending rate of each node. With the help of OPNET simulator and MATLAB, we compared this proposed protocol with Priority-based Congestion Control protocol and Optimized Congestion management protocol protocols, and simulation results suggest that the proposed protocol performs better than other approaches regarding aspects such as data loss rate and end-to-end delay.
The present study deals with the synthesis and electrospining of a new terpolymer nanofiber in order to determine the amount of diazinon and chlorpyrifos in water and fruit juice samples. The ...synthesized terpolymer and the prepared nanofiber were characterized using 1H NMR spectroscopy, FTIR spectroscopy, scanning electron microscopy, and gel permeation chromatography. The performance of terpolymer nanofiber, prepared as a sorbent for micro solid phase extraction was investigated for the extraction of diazinon and chlorpyrifos from aquaeous media. Then, the target analytes were desorbed from the coating with an organic solvent and analyzed by gas chromatography with flame ionization detector. Extraction efficiencies were significant (>90%) under the optimum condition. The proposed method also demonstrated good linear dynamic ranges for diazinon and chlorpyrifos (3–250 and 5–200 µg/L), and low limit of detections (0.5 and 0.7 µg/L) respectively. Moreover, under optimum condition for extraction of diazinon and chlorpyrifos, square of correlation coefficients (R2) of 0.9978 and 0.9953 and relative standard deviations of 4.6 and 5.1% were achieved, respectively. The recoveries for diazinon and chlorpyrifos were in the range of 85–97%.
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