Purpose: To evaluate endothelial cell density (ECD) and morphology of clear corneal grafts after Descemet stripping automated endothelial keratoplasty (DSAEK) and to determine the factors that influence graft ECD postoperatively.Methods: Seventy-seven eyes (38 right eyes) of 64 patients (34 female subjects) who underwent DSAEK for Fuchs’ endothelial dystrophy (n=38) or pseudophakic bullous keratopathy (n=39) were enrolled. Precut donor corneas were punched from the endothelial side using a trephine. The donor lamella was inserted into the anterior chamber using the pull-through technique with a Busin glide and forceps through a 5-mm clear cornea incision. In eyes with significant lens opacity, DSAEK was combined with cataract surgery. Confocal microscopy was performed at the final follow up examination to evaluate endothelial cell count and morphology as well as central graft thickness. Univariate analyses and multiple linear regression analyses were used to investigate recipient-, donor-, surgical-, and postoperative-related variables capable of influencing graft endothelial counts after DSAEK.Results: Mean age at the time of surgery was 62.3±15.6 years, and the patients were followed for 26.2±20.9 months postoperatively. Forty-six eyes (59.7%) underwent stand-alone DSAEK, whereas 31 eyes (40.3%) received DSAEK combined with cataract surgery. Donor trephination size was 8.0±0.21 mm, ranging from 7.50 to 8.25 mm. Mean donor age was 30.4±11.2 years and preoperative endothelial cell density was 3127.4±315.1 cells/mm2 which reduced to 1788.6±716.5 cells/mm2 postoperatively (P<0.001). Mean postoperative central graft thickness was 102.4±31.6μm. In the univariate analysis, postoperative ECD was significantly associated with death-to-preservation time (r=-0.31, P=0.046), central graft thickness (r=0.36, P=0.016), followup period (r=-0.56, P=0.005), and lenticule non-attachment (r=-0.31, P=0.049). Multiple regression analyses identified lenticule thickness (=10.62, P=0.003) and follow-up period (=-22.09, P=0.001) as the statistically significant characteristics influencing postoperative ECD.Conclusion: The main predictors of ECD after DSAEK were central graft thickness and the length of followup.Surgeons’ requests for ultrathin DSAEK donor grafts with the hope of improving visual outcomes may not have the desired outcome with respect to the postoperative ECD.

This paper reports the results of experimental removal process of ammonia from synthetically prepared ammonia solution using a microscale mixing loop air stripper. Effects of various operational parameters (such as pH, air flow rate, wastewater flow rate, and initial ammonia concentration) were evaluated. By increasing pH from 10 to 12. 25, the amount of KLa increased from 0. 26 to 0. 73 h-1. Considerable enhancement, about 150 %, can be found for KLa by changing the air flow rate from 280 to 700 mL/min under a fixed condition. The wastewater flow rate can also increase the value of KLa from 0. 22 to 0. 59 h-1. The values of KLa increased only about 20 %by changing the initial concentration of ammonia in the range between 50 and 500 mg/L. The results showed that any improvement concerning air stripping using microchannel was successfully carried out with enhancing the overall volumetric mass transfer coefficient (KLa) and providing higher mass transfer capabilities compared with other types of strippers, even for lower amounts of used air. The enhancement of mass transfer takes place by efficient mixing induced by the employed microchannel. It has been demonstrated that wastewater flow rate and air flow rate have significant effects on KLa. The optimal stripping conditions and mathematical modeling for ammonia removal and the relation between the parameters were determined using Response Surface Methodology (RSM) with Central Composite Design (CCD) method. The results demonstrate the advantages the proposed system possesses over conventional stripper types.

The paper deals with the optimization of uranium back extraction from the Alamine-336 loaded by synthetic solution (synthetic LOS) and Bandarabbas leach liquor (real LOS) by means of stripping process method. In this regard, the impact of two essential parameters including the reagent concentration and phase ratio (O: A) for stripping of alkaline agent containing sodium hydroxide (NaOH) and sodium carbonate (Na2CO3) togather with the pH for sodium chloride (NaCl) were investigated. To study these effects, a central composite design (CCD) under the response surface methodology (RSM) was employed. Based on the design of the experiments, the second-order regression model has been constructed to evaluate the optimzation of the stripping efficiency of uranium from Alamine-336. The optimum conditions for these stripping agents have been determined as NaCl (0. 6 mol L-1) with the ratios of O: A (1. 41) and pH (3. 1) NaOH (1. 33 mol L-1) with the ratio of O: A (1. 26) and Na2O3 (0. 72 mol L-1) with the ratio of O: A (1. 16). Under these optimal conditions, the stripping efficiency values up to %31, %45 and %54 were obtained for NaCl, NaOH, and Na2CO3 cases, respectively.

Molybdenum is determined by adsorptive cathodic stripping voltammetry in 0.15 M nitric acid solution containing 15 μM 2’,3,4’,5,7-pentahydroxyflavone (morin) as a ligand. In this medium, molybdenum is preconcentrated on a hanging mercury drop electrode and stripped cathodically in square-wave voltammetry mode, with a peak potential of -350 mV vs. Ag/AgCl (saturated KCl). The effect of various parameters (ligand concentration, supporting electrolyte composition, accumulation potential and collection time) on the sensitivity and linear range of the calibration curve are discussed. With controlled accumulation for 1 min, the detection limit (3s) was 0.45 ng ml-1 molybdenum and the calibration curve is linear up to 70 ng ml-1. The procedure is applied to the determination of molybdenum in real samples with satisfactory results.

It is well known that stripping (separation of aggregates and bitumen) is one of the reasons for asphalt-mixture failure in humid conditions. This could be due to moisture diffusion into the asphalt mixtures that is related to bond weakness between aggregate and bitumen in the asphalt mixtures, and consequently, damages the pavement surface. There are several standard laboratory methods for the evaluation of stripping resistance of asphalt mixtures. The modified Lottman indirect tensile test and determination of the TSR parameter is a common method for evaluating stripping resistance of asphalt mixtures. In this study, a method based on image processing is presented to determine the stripping resistance of asphalt mixtures, and a stripping parameter is developed as an indicator for assessing the moisture susceptibility of asphalt mixtures. The specimens in this research were prepared by mixing limestone materials, slag and hydrated lime filler. Comparison between stripping parameter and TSR values showed that the proposed method has sufficient reliability and is suitable for determining the stripping resistance of asphalt mixtures.

Adhesion of bitumen to Aggregates is the basis of the strength of the asphalt pavements. The term "stripping" is used for hot mix asphalt (HMA) mixtures to show the separation of asphalt binder film from aggregate surfaces, due primarily to the action of moisture and/or vapor. If this phenomenon is eliminated for any reason, stripping will be occurred. This problem not only is as a distinct distress but also can cause other asphalt distresses which are finally resulted in the overthrow of road. Mainly because this distress either results from or is dominated by moisture, it is usually called“moisture damage” or “moisture susceptibility”.The main goal in this research is to study stripping in asphalt mixtures. The key factors which must be considered in this research are aggregates and selecting the suitable approach for controlling and assessment of this distress in laboratory conditions. the most recent approach introduced is the rehabilitation and modification of asphalt mixtures against stripping, whether asphalt concrete or surface treatment. Thus, in this study on "Zanjan-Qazvin" freeway where this distress have usually been observed, the aggregates for constructing the asphalt was selected from sections of the aggregate the stripping intensity of which is higher than the others. First, the sensitivity of stripping was specified by XRF & XRD analysis. There is a requisite to do a realistic laboratory test method to predict moisture susceptibility of HMA mixtures. It was observed in the case histories that the asphalt pavements were saturated with water (55-80% saturated as specified in ASTM D4867 or AASHTO T283). Thereafter, in order to calculate the tensile strength ratio, it is required to consider unsaturated specimens some of which remained with no conditions. A laboratory test procedure that simulates such conditions will be more realistic. The cylindrical asphalt concrete specimens are constructed by marshal method. Thus, their durability is evaluated according to AASHTO-T283. In this method, those stabilities are measured by indirect tensile test; the amount of their stripping was previously estimated by boiling test. Results showed that according to literature boiling test method is not reliable enough to be accurate. On the other hand, the result of laboratory test of AASHTO-T283 is quantitative and much more technical. Also, using hydrated lime 3% for this material can be useful to reduce the adverse effect of stripping, and it can be used as a suitable anti-stripping. Based on the probabilistic analysis, all the specimens result either in Indirect Tensile Test, or in the TSR results. This showed the improvement of the strength. Also, the rate of increasing is close to that of the parabolic curve.WTAT test was carried out over the surface treatment specimens constructed using these aggregates. Hydrated lime was utilized as the most important anti-stripping additive for prevention and rehabilitation of this distress in all of the experiments.