279 research outputs found

    Evaluating the effects of language on international trade in MENA countries: A gravity-model approach

    Get PDF
    Prior studies have investigated the role of economic and noneconomic variables on international trade. A major factor, which has been studied less, is the language used in transactions and negotiations. We explore the effects of language connectedness and the Arabic language on international trade in thirteen countries in the Middle East and North Africa (MENA) region. We used a panel of bilateral data and gravity model for the countries of the region over the 2000 to 2018 period. Our analytic technique was the Poisson pseudo-maximum-likelihood (PPML) estimation method. The empirical outcomes indicate that speaking Arabic leads to an increase in export, that is, Arab nations prefer to export to the countries whose people speak their language. In addition, the language connectedness index, which depends on the extent to which the country's languages are spoken outside the country, is positively associated with the levels of exports and imports. Results further show that the GDP, population of the destination country, and political co-stability have significant positive impacts on the bilateral exports. Additionally, GDP, the population of the source country, political co-stability, and a common border have had significant positive influences on bilateral imports. The major contribution of this research is that the Arabic language has a significant and positive impact on trade among MENA countries

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

    Get PDF
    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

    Remifentanil versus dexmedtomidine for posterior spinal fusion surgery

    Get PDF
    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

    Analgesic effects of adding lidocaine to morphine pumps after orthopedic surgeries

    Get PDF
    Background: Opiate is used in patient-controlled intravenous analgesia pumps (PCIA) for controlling pain in post-surgical patients. Other drugs are remarkably added to opioid pumps to enhance quality, lengthen analgesia, and reduce side effects. Lidocaine, a local anesthetic which inhibits sodium channels, has anesthetic and analgesic effects when injected locally or intravenously. The objective of this study is to evaluate the analgesic effects of adding lidocaine 1 to different doses of morphine via IV pump to patient-controlled analgesia (PCA) after orthopedic surgeries. Materials and Methods: In a randomized clinical trial, 60 patients who had undergone orthopedic surgery of lower extremities were divided into three equal groups to control postoperative pain. Intravenous pump with 5 ml/h flow rate was used as the analgesic method. The solution consisted of lidocaine 1 plus 20 mg morphine for the first group, lidocaine 1 plus 10 mg morphine for the second group, and only 20 mg morphine for the third group (control group). Patients were checked every 12 h, and Visual Analog Scale (VAS), extra opioid doses, nausea/vomiting, and sedation scale were examined. Results: Pain score was lower in the first group compared to the other two groups. Mean VAS was 2.15 ± 0.2, 2.75 ± 0.2, and 2 ± 0.25 on the first day and 1.88 ± 0.1, 2.74 ± 0.3, and 2.40 ± 0.3 on the second day, respectively, in the three groups and the difference was statistically significant (P < 0.01 and -;0.05, respectively). Also, 10 of patients in the first group needed extra opioid doses, while this figure was 30 in the second group and 25 in the third group (P < 0.01). Nausea/vomiting and sedation scores were not statistically different among the three groups. Conclusion: Compared to lidocaine 1 plus 10 mg morphine or 20 mg morphine alone in PCIA, adding lidocaine 1 to 20 mg morphine decreases the pain score and opioid dose after orthopedic surgeries without having side effects

    Performance evaluation of non-thermal plasma on particulate matter, ozone and CO2 correlation for diesel exhaust emission reduction

    Get PDF
    This study is seeking to investigate the effect of non-thermal plasma technology in the abatement of particulate matter (PM) from the actual diesel exhaust. Ozone (O3) strongly promotes PM oxidation, the main product of which is carbon dioxide (CO2). PM oxidation into the less harmful product (CO2) is the main objective whiles the correlation between PM, O3 and CO2 is considered. A dielectric barrier discharge reactor has been designed with pulsed power technology to produce plasma inside the diesel exhaust. To characterise the system under varied conditions, a range of applied voltages from 11 kVPP to 21kVPP at repetition rates of 2.5, 5, 7.5 and 10 kHz, have been experimentally investigated. The results show that by increasing the applied voltage and repetition rate, higher discharge power and CO2 dissociation can be achieved. The PM removal efficiency of more than 50% has been obtained during the experiments and high concentrations of ozone on the order of a few hundreds of ppm have been observed at high discharge powers. Furthermore, O3, CO2 and PM concentrations at different plasma states have been analysed for time dependence. Based on this analysis, an inverse relationship between ozone concentration and PM removal has been found and the role of ozone in PM removal in plasma treatment of diesel exhaust has been highlighted

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

    Get PDF
    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

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

    Get PDF
    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

    Influence of pipe length and flow rate on nano-particle deposition in laminar circular pipe flows

    Get PDF
    The Lagrangian particle tracking provides an effective method for simulating the deposition of nano-particles as well as micro-particles as it accounts for the particle inertia effect as well as the Brownian excitation. However, using the Lagrangian approach for simulating ultrafine particles has been limited due to computational cost and numerical difficulties. The aim of this paper is to study the deposition of nano-particles in cylindrical tubes under laminar condition using the Lagrangian particle tracking method. The commercial Fluent software is used to simulate the fluid flow in the pipes and to study the deposition and dispersion of nano-particles. Different particle diameters as well as different pipe lengths and flow rates are examined. The results show good agreement between the calculated deposition efficiency and different analytic correlations in the literature. Furthermore, for the nano-particles with higher diameters and when the effect of inertia has a higher importance, the calculated deposition efficiency by the Lagrangian method is less than the analytic correlations based on Eulerian method due to statistical error or the inertia effect

    Evaluating equality in prescribing Novel Oral Anticoagulants (NOACs) in England: the protocol of a Bayesian small area analysis

    Get PDF
    Background Atrial fibrillation (AF) is the most common cardiac arrhythmia, affecting about 1.6% of the population in England. Novel oral anticoagulants (NOACs) are approved AF treatments that reduce stroke risk. In this study, we estimate the equality in individual NOAC prescriptions with high spatial resolution in Clinical Commissioning Groups (CCGs) across England from 2014 to 2019. Methods A Bayesian spatio-temporal model will be used to estimate and predict the individual NOAC prescription trend on ‘prescription data’ as an indicator of health services utilisation, using a small area analysis methodology. The main dataset in this study is the “Practice Level Prescribing in England,” which contains four individual NOACs prescribed by all registered GP practices in England. We will use the defined daily dose (DDD) equivalent methodology, as recommended by the World Health Organization (WHO), to compare across space and time. Four licensed NOACs datasets will be summed per 1,000 patients at the CCG-level over time. We will also adjust for CCG-level covariates, such as demographic data, Multiple Deprivation Index, and rural-urban classification. We aim to employ the extended BYM2 model (space-time model) using the RStan package. Discussion This study suggests a new statistical modelling approach to link prescription and socioeconomic data to model pharmacoepidemiologic data. Quantifying space and time differences will allow for the evaluation of inequalities in the prescription of NOACs. The methodology will help develop geographically targeted public health interventions, campaigns, audits, or guidelines to improve areas of low prescription. This approach can be used for other medications, especially those used for chronic diseases that must be monitored over time
    corecore