Effect of pulsed power on particle matter in diesel engine exhaust using a DBD plasma reactor

Nonthermal plasma (NTP) treatment of exhaust gas is a promising technology for both nitrogen oxides (NOX) and particulate matter (PM) reduction by introducing plasma into the exhaust gases. This paper considers the effect of NTP on PM mass reduction, PM size distribution, and PM removal efficiency. The experiments are performed on real exhaust gases from a diesel engine. The NTP is generated by applying high-voltage pulses using a pulsed power supply across a dielectric barrier discharge (DBD) reactor. The effects of the applied high-voltage pulses up to 19.44 kVpp with repetition rate of 10 kHz are investigated. In this paper, it is shown that the PM removal and PM size distribution need to be considered both together, as it is possible to achieve high PM removal efficiency with undesirable increase in the number of small particles. Regarding these two important factors, in this paper, 17 kVpp voltage level is determined to be an optimum point for the given configuration. Moreover, particles deposition on the surface of the DBD reactor is found to be a significant phenomenon, which should be considered in all plasma PM removal tests

Field trial of a 15 Tb/s adaptive and gridless OXC supporting elastic 1000-fold all-optical bandwidth granularity

An adaptive gridless OXC is implemented using a 3D-MEMS optical backplane plus optical modules (sub-systems) that provide elastic spectrum and time switching functionality. The OXC adapts its architecture on demand to fulfill the switching requirements of incoming traffic. The system is implemented in a seven-node network linked by installed fiber and is shown to provide suitable architectures on demand for three scenarios with increasing traffic and switching complexity. In the most complex scenario, signals of mixed bit-rates and modulation formats are successfully switched with flexible per-channel allocation of spectrum, time and space, achieving over 1000-fold bandwidth granularity and 1.5 Tb/s throughput with good end-to-end performance

Effect of polymer and irrigation regimes on dry matter yield and several physiological traits of forage sorghum

Drought stress is one of the most serious problems in crops production in the arid and semi-arid regions. Application of some materials such as superab A200 polymers (SAP) in soil can improve soil water reservation. They can also decrease water losses, fertilizer leaching in soils, effects of water deficiency in plants and so can improve the yield in the arid and semi-arid regions. This experiment was conducted on forage sorghum (Sorghum bicolor (L.) variety ‘Speedfeed’) in Zahedan, Iran during 2010 season. The experimental design was a split-plot with two factors including four irrigation regimes (providing 40, 60, 80 and 100% of the water requirement of sorghum calculated from pan evaporation) as main plots and four amounts of SAP (0, 75, 150 and 225 kg ha-1) as subplots in a completely randomized block design with three replications. Irrigation level and SAP had significant effects on chlorophyll index, leaf area index, leaf area duration, crop growth rate, relative water content and dry matter. The results indicate that irrigation to meet 80% of the water requirement with 75 kg ha-1 SAP which may provide a desirable dry matter.Keywords: Dry matter yield, forage sorghum, growth analysis, irrigation regime, superab A200 polyme

Remifentanil versus dexmedtomidine for posterior spinal fusion surgery

Background: Controlling the hemodynamic situation of patients who have spinal operation is of prime importance, and maintaining the heart rate and blood pressure in normal or low- normal levels in these patients can reduce their bleeding loss. One of the commonly used drugs for this purpose is remifentanil. Another sedative-hypnotic-analgesic drug, with acceptable effects is dexmedetomidine. The aim of this study was to compare the effect of dexmedetomidine with remifentanil in spinal operation. Methods: In a double blind randomized clinical trial, using random sampling method, 60 patients with the age range of 15-65 years who were candidates for posterior spinal fusion operation were included. Induction of anesthesia was performed, and both groups received isoflurane 1 during the surgery. Remifentanil was injected via infusion pump in one group. The patients in the trial group received dexmedetomidine. As trial outcomes, heart rate and blood pressure were measured before, after induction and during the operation. Pain score, sedation score and the need to analgesic therapy were recorded in the recovery room and the ward. Independent sample t-test and chi-square were used for statistical analysis. Results: Dexmedetomidine had a significant lowering impact on intraoperative blood pressure and heart rate compared to remifentanil (p<0.001). The mean of sedation scores after extubation in patients who received dexmedetomidine was significantly higher than the sedation scores in patients who received remifentanil (p<0.001). The mean of post-extubation and recovery pain score in patients taking remifentanil was significantly higher than patients taking dexmedetomidine (p<0.05). Conclusion: Dexmedetomidine in patients with spinal operation is associated with lower postoperative pain score and intraoperative bleeding. Hemodynamic effects are significantly better in patients received dexmedetomidine

An advanced computational intelligent framework to predict shear sonic velocity with application to mechanical rock classification

Shear sonic wave velocity (Vs) has a wide variety of implications, from reservoir management and development to geomechanical and geophysical studies. In the current study, two approaches were adopted to predict shear sonic wave velocities (Vs) from several petrophysical well logs, including gamma ray (GR), density (RHOB), neutron (NPHI), and compressional sonic wave velocity (Vp). For this purpose, five intelligent models of random forest (RF), extra tree (ET), Gaussian process regression (GPR), and the integration of adaptive neuro fuzzy inference system (ANFIS) with differential evolution (DE) and imperialist competitive algorithm (ICA) optimizers were implemented. In the first approach, the target was estimated based only on Vp, and the second scenario predicted Vs from the integration of Vp, GR, RHOB, and NPHI inputs. In each scenario, 8061 data points belonging to an oilfield located in the southwest of Iran were investigated. The ET model showed a lower average absolute percent relative error (AAPRE) compared to other models for both approaches. Considering the first approach in which the Vp was the only input, the obtained AAPRE values for RF, ET, GPR, ANFIS + DE, and ANFIS + ICA models are 1.54%, 1.34%, 1.54%, 1.56%, and 1.57%, respectively. In the second scenario, the achieved AAPRE values for RF, ET, GPR, ANFIS + DE, and ANFIS + ICA models are 1.25%, 1.03%, 1.16%, 1.63%, and 1.49%, respectively. The Williams plot proved the validity of both one-input and four-inputs ET model. Regarding the ET model constructed based on only one variable,Williams plot interestingly showed that all 8061 data points are valid data. Also, the outcome of the Leverage approach for the ET model designed with four inputs highlighted that there are only 240 "out of leverage" data sets. In addition, only 169 data are suspected. Also, the sensitivity analysis results typified that the Vp has a higher effect on the target parameter (Vs) than other implemented inputs. Overall, the second scenario demonstrated more satisfactory Vs predictions due to the lower obtained errors of its developed models. Finally, the two ET models with the linear regression model, which is of high interest to the industry, were applied to diagnose candidate layers along the formation for hydraulic fracturing. While the linear regression model fails to accurately trace variations of rock properties, the intelligent models successfully detect brittle intervals consistent with field measurements

Heavy Metals Residue in Cultivated Mango Samples from Iran

Background: Heavy metals contaminations are recognized as the serious risk to our environment. The aim of the present study was to analyze heavy metals residue in cultivated mango samples from Iran. Methods: Totally, 72 mango samples were randomly collected among six different mango genotypes cultivated in Southern Iran from June to July 2015. Lead, chromium, cadmium, and arsenic were determined using an atomic absorption spectrometer. Analysis of variance was performed with SAS 9.0. Descriptive statistics, multivariate analysis, and Duncan multiple range tests were done with a significance level of p<0.05. Results: Measurement of heavy metals in all the mango samples showed various level ranges of lead (0.008-0.05 ppm), chromium (0.01-0.1 ppm), cadmium (0.002-0.014 ppm), and arsenic (0.01-0.04 ppm). Heavy metal levels were significantly (p0.05) was seen between heavy metals residue and variety in genotypes of mango samples. Conclusion: The average amount of heavy metals residue in mango samples found in the current study were generally below the maximum acceptable levels indicating acceptable safety of these products

The prediction model for additively manufacturing of NiTiHf high-temperature shape memory alloy

NiTi-based alloys are one of the most well-known alloys among shape memory alloys having a wide range of applications from biomedical to aerospace areas. Adding a third element to the binary alloys of NiTi changes the thermomechanical properties of the material remarkably. Two unique features of stability and high transformation temperature have turned NiTiHf as a suitable ternary shape memory alloys in various applications. Selective laser melting (SLM) as a layer-based fabrication method addresses the difficulties and limitations of conventional methods. Process parameters of SLM play a prominent role in the properties of the final parts so that by using the different sets of process parameters, different thermomechanical responses can be achieved. In this study, different sets of process parameters (PPs) including laser power, hatch space, and scanning speed were defined to fabricate the NiTiHf samples. Changing the PPs is a powerful tool for tailoring the thermomechanical response of the fabricated parts such as transformation temperature (TTs), density, and mechanical response. In this work, an artificial neural network (ANN) was developed to achieve a prediction tool for finding the effect of the PPs on the TTs and the size deviation of the printed parts

The role of non-thermal plasma technique in NOx treatment : a review

Non-thermal plasma (NTP) has been introduced over the past several years as a promising method for nitrogen oxide (NOx) removal. The intent, when using NTP, is to selectively transfer input electrical energy to the electrons, and to not expend this in heating the entire gas stream, which generates free radicals through collisions, and promotes the desired chemical changes in the exhaust gases. The generated active species react with the pollutant molecules and decompose them. This paper reviews and summarizes relevant literature regarding various aspects of the application of NTP technology on NOx removal from exhaust gases. A comprehensive description of available scientific literature on NOx removal using NTP technology is presented, including various types of NTP, e.g. dielectric barrier discharge, corona discharge and electron beam. Furthermore, the combination of NTP with catalyst and adsorbent for better NOx removal efficiency is presented in detail. The removal of NOx from both simulated gases and real diesel engines is also considered in this review paper. As NTP is a new technique and is not yet commercialized, there is a need for more studies to be performed in this field

Laboratory Evaluation of Five Chitin Synthesis Inhibitors Against the Colorado Potato Beetle, Leptinotarsa decemlineata

Results of laboratory experiments are reported that tested the effects of five chitin synthesis inhibitors, diflubenzuron, cyromazine, lufenuron, hexaflumuron and triflumuron. on second instars of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Crysomelidae), originally collected from potato fields of Bostanabaad, a town 66 km southeast of Tabriz, Iran. In bioassays, the larvae were fed potato leaves dipped in aqueous solutions containing chitin synthesis inhibitors. The mortalities and abnormalities of the treated larvae were recorded 72 hours after treatments. LC50 values were 58.6, 69.6, 27.3, 0.79 and 81.4 mg ai/ L for diflubenzuron, cyromazine, lufenuron, hexaflumuron and triflumuron, respectively. Compared with phosalone, which is one of the common insecticides used for controlling this pest in Iran, lufenuron and hexaflumuron seem to be much more potent, and if they perform equally well in the field, they would be suitable candidates to be considered as reduced risk insecticides in management programs for L. decemlineata due to much wider margin of safety for mammals and considerably fewer undesirable environmental side effects

Experimental Study on the Optimization of Dielectric Barrier Discharge Reactor for NOx Treatment

In this paper, a comprehensive study of a DBD reactor is conducted to investigate the optimum operating conditions of the reactor for NOx treatment. For each parameter, the objective is to find the maximum NOx removal efficiency with the minimum consumed power. Different effective parameters of the reactor i.e. electrode length and diameter, electrode and dielectric materials as well as parameters of power generator, i.e. voltage and frequency, are investigated. The results show that for this configuration, the electrode with 20 cm length and 10 mm diameter has the best performance. Aluminum as the inside electrode material and quartz as the dielectric material are selected. Furthermore, the optimum value for the pulse frequency is 16.6 kHz. For the mentioned optimum conditions, the NOx removal efficiency achieved is equal to almost 82% at the input power of 486 W. Furthermore, the highest achieved NOx removal is almost 92% at the input power of 864 W. The results of this paper can be used to reduce the energy consumption of NTP systems to acceptable levels