In this work, atmospheric plasma spraying (APS) and suspension plasma spraying (SPS) are employed for developing micro/nano morphologies of superhydrophobic coatings with high water repellence and ...mobility. Accordingly, multiple coatings were developed with different surface morphologies, then by isolating the effect of surface chemistry using a stearic acid treatment, the importance and influence of the achieved morphologies on wetting behavior of the coatings were investigated. Experimental results show that, although coatings developed by the APS process may reach water contact angles as high as 145°, the water mobility of these coatings is low due to relatively large morphological features resulting from the micron-sized feedstock powder. On the other hand, coatings developed by SPS show superior water repellence (manifested through water contact angles as high as 167°) as well as improved mobility (displayed through water sliding angles as small as 1.3°) due to dual-scale submicron/nano (hierarchical) roughness attributed to the submicron size particles in the feedstock. The dynamic behavior of an impinging water droplet is studied and compared to other existing natural and fabricated superhydrophobic surfaces.
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•AAPS and SPS coating techniques are employed to develop submicron-textured, hydrophobic and superhydrophobic TiO2 coatings.•APS coatings show contact angles as high as 145°, but lack the desired water mobility.•SPS coatings show superior water repellence (contact angle ~167°) and improved mobility (sliding angle as ~1.3°).•Morphology and structure of the coatings and their relationship with different wetting behavior of the coatings is studied.•Dynamic wetting of the coatings is shown to be comparable to existing natural and fabricated superhydrophobic surfaces.
► The instability of elliptic liquid jets is studied by theory and experiment. ► Based on the Cosserat theory, a linear instability analysis is performed. ► Using spatial analysis, jet profile, ...axis-switching, and breakup are predicted. ► By increasing the ellipticity, the growth rate and instability range are increased. ► In high-speed jets, longer nozzles produce jets with a shorter contact length.
Theoretical and experimental investigations are conducted to analyze the instability of a low-speed liquid jet emerging from an elliptic nozzle. The complexity of viscous free surface flow analysis for an asymmetric geometry is simplified using an approach based on the Cosserat theory (also called director theory) which reduces the exact three-dimensional equations to a system depending only on time and on a single spatial variable. This work is mainly focused on the spatial instability analysis to examine the key characteristics of an elliptic jet such as jet profile, axis-switching and breakup length. In the experimental part, both natural (free) and excited (forced) breakup behaviors are studied. In the natural breakup, the effects of nozzle’s ellipticity and length to diameter ratio are examined. In the forced breakup case, disturbances are applied to the jet, by modulating the jet exit velocity using a piezoelectric actuator with given sinusoidal perturbations. The spatial evolution of the jet shape is captured with a high speed camera. Liquid jet instability is studied for various nozzle geometries over a specific range of jet velocities and excitation frequencies. Results are compared with conventional circular nozzles which can be considered as a special case of an elliptic jet.
Abstract Background and aims An increase in the intracranial pressure (ICP) might aggravate patient outcomes by inducing neurologic injuries. In patients with increased ICP the optic nerve sheath ...diameter (ONSD) increases due to its close association with the flow of cerebrospinal fluid. The present study was an attempt to evaluate the efficacy of sonographic ONSD in estimating ICP of patients who are candidates for lumbar puncture (LP). Materials and methods In this descriptive prospective study, the ONSD was measured before LP using an ultrasonography in 50 nontraumatized patients who were candidates for LP due to varies diagnoses. Immediately after the sonography, the ICP of each patient was measured by LP. Correlation tests were used to evaluate the relationship between ICP and the sonographic diameter of the optic nerve sheath. Receiver operating characteristic curve was used to find the optimal cut-off point in order to diagnose ICP values higher than 20 cm H2 O. Results The means of the ONSD were 5.17 ± 1.01 and 5.19 ± 1.06 mm on the left and right sides, respectively ( P = .552). The mean ONSD for the patients with increased ICP and normal individuals were 6.66 ± 0.58 and 4.60 ± 0.41 mm, respectively ( P < .001). This mean was significantly correlated with ICP values ( P < .05; r = 0.88). The ONSD of greater than 5.5 mm predicted an ICP of ≥ 20 cm H2 O with sensitivity and specificity of 100% (95% CI, 100-100) ( P < .001). Conclusion The sonographic diameter of the optic nerve sheath might be considered a strong and accurate predicting factor for increased intracranial pressure.
The main question of the present study is: How is it that despite the West’s insistence on negotiation on Tehran’s missile programme and the possibility of sanctions being intensified in the event of ...Iran’s refusal, the Tehran authorities reject any negotiations in this regard? The findings of the present study indicate that Iranian political authorities, and in particular, the Iranian Leader, have a realistic view towards the country’s defence issue and continue to lay emphasis on such measures as increasing military capability, establishing a balance of power and self-sufficiency in arms manufacturing. Iran’s fears of replication of Iraq’s and Libya’s disarmament and the subsequent overthrow of the political systems of these governments, distrust in the West in the negotiations and the related consequences, lack of a strategic partner, the bitter experience of war with Iraq, and the continuous threats made by the USA and Israel have caused Iran to reject any request for negotiations about its missile programme.
Beginning in 2016 Iran's naval posture in the Persian Gulf changed from a defensive-offensive strategy, which had been in effect since 2001, to an offensive one. This was reinforced in 2019-2020, ...when, in response to the Trump administration, Iranian military strategists determined that any potential confrontation with the country's adversaries is likely to take place at sea rather than on land or in the air. After the end of the Iran-Iraq war, Iran's naval strategies can be divided into three, each coinciding with different periods: defensive (1988-2001), defensive-offensive (2001-2016) and offensive (since 2016). The intensification of the US military presence in the Persian Gulf and issuing threats against Iran have played a central role Tehran's adoption of an offensive naval strategy. Features of this new strategy include the development of ballistic and cruise missile programmes; development and deployment of drones in naval manoeuvres; the use of air defence in supporting naval operations; deepening Iran's military presence in Persian Gulf islands; ensuring the ability to disrupt the flow of energy; conducting naval manoeuvres in collaboration with trans-regional powers and continued use of proxy warfare. Tehran believes the new strategy will help it better prepare for international threats.
The main objective of this study was to use flash boiling atomization as a new method to inject suspensions with high solid content into the high-power plasma flow. The water-based suspension was ...prepared with submicron titanium oxide particles with an average size of 500 nm. The investigated solid concentrations were 20, 40, 55 and 70 wt%. Two plasma torches operated at 33, 70 and 110 kW were used to investigate the effect of increasing power on the deposited microstructure and deposition efficiency. At low torch power, the deposition efficiency decreased with increasing solid concentration, and deposits with a high number of unmelted particles were obtained with 70 wt% suspensions. At high torch power, the deposition efficiency increased with increasing solid concentration, and dense deposits were obtained with 70 wt% suspensions. XRD analysis was performed on all deposits to determine the distribution of rutile and anatase phases. The percentage of the anatase phase varied from 35.7% to 66.9%, depending on the power input and solid concentration.
Atomization of liquid jets in gaseous crossflows has many natural and industrial applications, for example, in fuel atomization in gas turbine engines, rocket engines, film cooling, and, recently, ...suspension and solution precursor plasma spraying processes for the development of advanced coatings. Viscosity and density of the gaseous medium may significantly vary in applications such as plasma spraying, which can affect the instability waves on the liquid jet column, resulting in a major change in the mechanism of primary and secondary breakups. In this study, a numerical model is used to investigate the impact of gas viscosity on breakup mechanisms for a wide range of density ratios and Weber numbers. Due to many challenges, only a few comprehensive atomization measurements have been performed on this subject. However, novel computational models could provide the atomization process with a thorough picture in the last two decades. The incompressible variable-density Navier–Stokes equations are solved by using finite volume schemes, and a geometric volume-of-fluid technique is used to track the gas–liquid interface. In our parametric study, three sets of density ratios and Weber numbers are chosen. In each set, four cases with different orders of magnitude of gaseous Reynolds number are simulated. Different characteristics of jet atomization are analyzed, such as the jet trajectory, breakup location, and surface instabilities generated along the jet column. Ultimately, the effects of gaseous Reynolds number, density ratio, and Weber number on jet deformation and breakup mechanisms are discussed.
Iran's foreign policy changed with the spread of Covid‐19 in three main ways. First, the pandemic propelled its health diplomacy into prominence. Second, the pandemic altered the customary view of ...the country's diplomacy. For more than four decades, Iran has regarded this diplomacy from the perspective of humanitarianism and ethics. But the pandemic imparted new object lessons. Third, the pandemic ushered Iran into a new era of cooperation with the World Health Organization (WHO). Considering Iran's medical and other scientific achievements over the past three decades, it seems likely that pursuing this diplomacy can improve Iran's position in the WHO and enhance its prestige and influence within this and other international organizations, possibly easing the pressure of sanctions in the future.
Induction of anesthesia for emergency procedures, without prior gastric preparation and incomplete fasting, is associated with the risk of reflux of stomach contents and aspiration. This study aimed ...to evaluate the effect of intravenous (IV) metoclopramide administration on gastric emptying in opium users, candidate for procedural sedation and analgesia (PSA).
In the present case-control study, opium-dependent (case) and non-dependent (control) patients in need of PSA were administered with 10 mg IV metoclopramide after undergoing gastric ultrasonography for determination of its area and contents. Then, 30 minutes after the administration of metoclopramide, the area and contents of the stomach were measured again and compared with the measures obtained before the intervention.
135 patients were evaluated in three groups of 45, including the case, control, and placebo groups. The three groups were similar regarding mean age (p = 0.068), sex (p = 0.067), weight (p = 0.596), height (p = 0.671), body mass index (BMI) (p = 0.877), duration of fasting (p = 0.596), and type of gastric contents (p = 0.124). Mean antral cross-sectional area (CSA) of the study participants in the case, control, and placebo groups before the administration of the drug was 8.49 ± 1.40, 8.31 ± 2.56, and 6.56 ± 1.72 cm
, respectively. Mean gastric area in the case (p < 0.001) and control (p < 0.001) groups had significantly decreased after the intervention. Mean antral gastric grade of gastric contents in the case (p < 0.001) and control (p < 0.001) groups had significantly decreased after the intervention.
It seems that metoclopramide administration in opium users in need of PSA leads to a significant decrease in mean gastric area and increases gastric emptying.
