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[en] A new concept for a micro pressure sensor is demonstrated. The pressure difference between the inlet and the outlet of glass nanochannels is obtained by measuring the electrokinetically generated electric potential. To demonstrate the proposed concept, experimental investigations are performed for 100 nm wide nanochannels with sodium chloride solutions having various concentrations. The proposed pressure sensor is able to measure the pressure difference within a 10% deviation from linearity. The sensitivity of the electrokinetic pressure sensor with 10−5 M sodium chloride solution is 18.5 µV Pa−1, which is one order of magnitude higher than that of typical diaphragm-based pressure sensors. A numerical model is presented for investigating the effects of the concentration and the channel width on the sensitivity of the electrokinetic pressure sensor. Numerical results show that the sensitivity increases as the concentration decreases and the channel width increases
[en] Limonium insigne (Plumbaginaceae) is a perennial halophyte endemic to the SE of the Iberian Peninsula. Experiments were conducted to determine the effects of different salinities (0, 100, 200 and 400 mM NaCl) on the seed germination of L. insigne under different temperature regimes (20/10, 25/15, 30/20 and 35/25 degree C), both in a 14 h light and 10 h dark photoperiod. Seed germination of L. insigne was affected significantly by salinity levels, temperature and their interaction. Maximum germination was observed in the least saline media (100 mM NaCl) and distilled water (0 mM NaCl) at 20/10 degree C temperature. No seeds germinated at concentrations higher than 200 mM NaCl at the highest temperature (35/25 degree C). The increase in salinity delayed the beginning and ending of germination, reduced final germination percentage and increased mean time to germination. The rate of germination decreased with an increase in salinity and temperature. (author)
[en] It is well known that iron is one of the most common impurity elements sound in aluminum and its alloys. Iron in the aluminum forms an intermetallic compounds such as FeAl3. The FeAl3 particles on the aluminum surface are one of the most detrimental phases to the corrosion process and anodizing procedure for aluminum and its alloys. Trial and error surface treatment will be carried out to find the preferential and effective removal of FeAl3 particles on the surfaces without dissolution of aluminum matrix around the particles. One of the preferable surface treatments for the aim of getting FeAl3 free surface was an electrochemical treatment such as cathodic current density of -2 kAm-2 in a 20-30 mass% HNO3 solution for the period of 300s. The corrosion characteristics of aluminum surface with FeAl3 free particles are examined in a 0.1 kmol/m3 NaCl solution. It is found that aluminum with free FeAl3 particles shows higher corrosion resistance than aluminum with FeAl3 particles
[en] Peculiarities of the kinetics and the mechanism of corrosion of (α-Al-Mg2Si) aluminum euthectic alloy in a 3% NaCl solution imitating the marine water have been studied using the methods of anodic potential-dynamic polarization curves and layer-by-layer analyses of solid-phase interaction products (the AES, EDX, petrographic analysis, SEM, SEI), as well as AAS-analysis of electrolyte after the electrolysis. It has been established that, at the anodic polarization during different corrosion stages, amorphous Al2O3, silicon, and SiO2 (cristobalite phase) are formed as sold-phase products, while Mg2Si is partially transported to the solution as Mg- and SiO32--ions.
[en] Highlights: • Alternating polarization (AP) is tested with a capacitive deionization (CDI) stack. • AP enhances CDI performance without the formation of inversion peaks. • A maximum in salt adsorption capacity occurs halfway through the cycling test. • The electrodes are oxidized during cycling to possess negative surface charge. • Surface charge distribution is used to interpret salt removal resulting from AP. - Abstract: Alternating polarization (AP) at ±1.2/0 V is performed on a capacitive deionization stack assembled with carbon xerogel (CX) electrodes. Long-term testing shows enhanced cycling stability without the formation of inversion peaks. AP also leads to an arch-shaped plot of salt adsorption capacity (SAC) versus cycling time, with the highest SAC of approximately 3 mg (NaCl) g"−"1 (CX) during this long-term test. Characterization of both the freshly prepared and cycled electrodes depict that AP results in surface charge of all the electrodes being modified from positive to negative character. By leveraging balances of electronic, surface, and ionic charges in carbon micropores, it is found that a portion of the electronic charge contributes to the ionic charge for salt adsorption, and another portion is parasitically consumed to balance the surface charge during the charge reconciliation process. When the consumption of electronic charge for charge reconciliation becomes minimal, both the positive and negative surface charges are nearly equivalent on the CX electrode. Under such a condition, the highest SAC values can be achieved for AP testing.
[en] Soil salinity is a major environmental issue in arid and semiarid regions of the world. Acacia has very important role for salt affected barren lands due to its high salinity tolerance potential. The aim of the present study was to explore the genetic differences among Acacia ampliceps and Acacia nilotica regarding their response to salinity. Three-weeks old seedlings of both species were transplanted in half strength Hoagland nutrient solution having five salt levels (control,100, 200, 300 and 400 mM NaCl) with four replications in completely randomized design with factorial arrangement. After eight weeks of transplantation, the plants were harvested and data for shoot and root length and their fresh and dry weights were recorded. Na/sup +/, K/sup +/ and Cl/sup -/concentration of both root and shoot was determined. All the growth parameters of both species declined significantly in response to salinity. Acacia ampliceps was more salt tolerant than Acacia nilotica with better growth owing to higher K/sup +/: Na/sup +/ ratio in plant tissues. (author)
[en] Full text: Crystalline insulating thin films are promising substrates to support nanostructures when it is necessary to reduce charging effects with the support. For example, this kind of materials can be used in systems where the ultra-thin film acts as a tunnel barrier improving the performance of a device. Moreover, crystalline and insulating films have been also used to control the growth of oriented metal nanocrystals and nanoparticles. Most of the materials used to support and electronically isolate nanostructures for technological applications are crystalline oxide and alkali halides thin films. However, crystalline oxide thin layers are usually oxygen deficient. Alkali halides thin films have been deposited mainly by evaporation in Knudsen effusion cells since this technique allows growing ultra thin films crystalline oriented. There are few previous reports of alkali halides films grown by pulsed laser deposition (PLD) technique even though this method has been used successfully for deposition of other cubic materials. Arieta et al. deposited polycrystalline films by PLD on glass and silicon substrates founding that the crystalline orientation strongly depends on the substrate. However to our knowledge, there are no other studies of the effect of the background pressure on the crystallinity of NaCl films and the formation of the film increasing the number of laser pulses. We report the epitaxial growth of NaCl films on silicon and glass substrates by PLD. The structure of the films was characterized by X-ray diffraction and their morphology was studied by scanning electron microscopy. The effects of Ar background pressure on the crystallinity of the films have been investigated. The evolution of the film growth was also studied. Our results prove that PLD is suitable to grow oriented crystalline NaCl layers of micrometer dimensions. (author)
[en] The aim of the present study is to establish a time and cost effective Na["1"8F]F preparation method. The process is composed of absorbing radioactive impurities with cation exchange cartridge (CM), trapping "1"8F-fluroide with QMA cartridges, and formulating the product. The total preparation time determined at the end of bombardment was 4 min and the radiochemical yield was 82 % (n = 29). The final formulated Na["1"8F]F solution satisfies the USP criteria for quality control. (author)
[en] Objective: To determine the efficacy of saline injection in post-acne atrophic scars on face. Study Design: Non-randomized clinical trial. Place and Duration of Study: Department of Dermatology, Jinnah Postgraduate Medical Centre, Karachi, from January to July 2019. Methodology: All patients with mild, moderate and severe post-acne atrophic scars, above the age of 15 years without any comorbid conditions were included in the study. Intra-dermal isotonic saline solution was administered under local anesthesia, into the scars weekly for 12 weeks. The results were assessed subjectively and objectively by photographs, Sharquie scoring system and Dermatology Life Quality Index (DLQI) at baseline and at the end of treatment. SPSS 23 was used for analyzing data. Results: Out of 49 patients, 41 (83.7%) were females and 8 (16.3%) were males. The mean age was 24.69 ±4.35 years. According to Sharquie scoring system of grading scars at baseline, 3 (6.1%), 34 (69.4%) and 12 (24.5%) patients had mild, moderate and severe scarring respectively while at the end of treatment, 35 (71.4%), 12 (24.5%) and 2 (4.1%) patients had mild, moderate and severe scarring respectively (p=0.001). Regarding degree of satisfaction of patients, 6 (12.2%), 27 (55.1%), 12 (24.5%) and 4(8.2%) patients were mildly, moderately, greatly and completely satisfied respectively. The mean DLQI was 12.14 ±3.29 and 5.86 ±2.26 at baseline and at the end of treatment respectively (p=0.001). Conclusion: The response of saline injection was significant in all types of post-acne atrophic scars as assessed with Sharquie score and DLQI, but more significant in mild and moderate scars, without any significant side effects. (author)
[en] The cavitation behavior of A5083 alloy is investigated utilizing a vibratory cavitation tester. The tester(20.3kHz frequency) was manufactured according to ASTM G-32. The cavitation behavior of the specimens was examined by weight loss measurement and surface morphology change with peak-to-peak amplitudes and solutions. In order to investigate the cause of the damaged specimen's surface morphology change, the fluid velocity profile adjacent to vibrating specimen was measured by laser doppler velocimeter(LDV). The amount of weight loss was increased linearly with time after an incubation period. Cavitation test data in 3.5wt% NaCl solution showed that the amount of weight loss at small peak-to-peak amplitude(10μm) was increased by synergy effect of mechanical vibration and electrochemical corrosion. Such synergy effect, however, became less significant in deionized water and 3.5wt% NaCl solution with bigger amplitude(>20μm) where the mechanical damage predominates the corrosion damage. As the peak-to-peak amplitude was altered the damaged specimen exhibited significant morphology change. The circular type of damaged surface was shifted to the outer rim of the specimen and the damage intensity was increased with increasing amplitude. This morphology change could be attributed to the turbulence intensity whose maximum is found at the rim of specimen. LDV results have shown that turbulence intensity, which causes cavitative damage, increases with increasing amplitude, resulting in more intense damage. It is also suggested that the mechanism of morphology change could be resolved through farther LDV experiments. However, the obtained data did not showed exact correlation with the damaged surface morphology because the data were not obtained at the exact spots but relatively apart spots. We found some relationships with the damaged surface morphology and the LDV data