Experimental study and mathematical model development for the effect of water depth on water production of a modified basin solar still

Freshwater is constantly shrinking with the confindness of water resources. Therefore, desalination of seawater is given great attention. Renewable energy sources also become of high importance to reduce carbon emissions. Thus, this study is concerned with the design, fabrication, and testing of a new single-slope double-basin solar still as a renewable energy-driven desalination system. It differs from the conventional solar stills by having two basins. The experiments were conducted to compare the performance of both conventional and modified solar stills. As a design parameter that substantially affects the performance, the still water depth was investigated. A new straightforward, accurate model is developed to predict both systems' performance for the design and optimization within a maximum deviation of ±6.6%. The results indicated that the day's productivity for the new and conventional stills at 2 cm water depth was 2.855 and 1.785 L/m² per day, respectively, by an increase of 59.9% with a thermal efficiency improvement of 61.3%. Also, a rise in the equivalent water depth de from 2 cm to 3 cm reduces the accumulated productivity by 14.36% and 15.41% for the SSDBSS and SSSS, respectively. Additionally, the daily thermal efficiency of the SSDBSS and SSSS is 25% and 15.5% for water depth de of 2 cm, respectively. The maximum values of the total heat transfer coefficient were also evaluated to be 15.4 and 55 W/m².ºC for the lower and upper basins of the modified system, respectively, and 30.18 W/m².ºC for the conventional system.publishedVersionPeer reviewe

Experimental investigation on the compressibility of Al/Al2O3 nanocomposites

The scientific importance of nanocomposites is being increased due to their improved properties. This paper introduces an experimental investigation on the relationship between the reinforcement weight fraction and compressibility of Al/Al2O3 during high energy ball milling. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterise the produced powder. The results showed that the grain size of milled powders was about 43 nm with a noticeable presence of agglomerates at 10 wt.% of Al2O3. By increasing Al2O3 weight fraction to 12% the decrease in grain size was very. With up to 12 wt.% of Al2O3, microhardness increases from 62 to 150 HV due to the decrease of the crystallite size. The compressibility behaviour of the nanocomposite powder was decreased slowly by increasing Al2O3 content due to work hardening on the matrix powder. Copyright 2016 Inderscience Enterprises Ltd.Scopu

Experimental Analysis and CFD Modeling for Conventional Basin-Type Solar Still

With the rising population, environmental pollution, and social development, potable water is reducing and being contaminated day by day continually. Thus, several researchers have focused their studies on seas and oceans in order to get potable fresh water by desalination of their saltwater. Solar still of basin type is one of the available technologies to purify water because of free solar energy. The computational fluid dynamic CFD model of the solar still can significantly improve means for optimization of the solar still structure because it reduces the need for conducting large amount of experiments. Therefore, the main purpose of this study is presenting a multi-phase, three-dimensional CFD model, which predicts the performance of the solar still without using any experimental measurements, depending on the CFD solar radiation model. Simulated results are compared with experimental values of water and glass cover temperatures and yield of fresh water in climate conditions of Sheben El-Kom, Egypt (latitude 30.5◦ N and longitude 31.01◦ E). The simulation results were found to be in acceptable agreement with the experimental measured data. The results indicated that the daily simulated and experimental accumulated productivities of the single-slope solar still were found to be 1.982 and 1.785 L/m2 at a water depth of 2 cm. In addition, the simulated and experimental daily efficiency were around 16.79% and 15.5%, respectively, for the tested water depth.With the rising population, environmental pollution, and social development, potable water is reducing and being contaminated day by day continually. Thus, several researchers have focused their studies on seas and oceans in order to get potable fresh water by desalination of their saltwater. Solar still of basin type is one of the available technologies to purify water because of free solar energy. The computational fluid dynamic CFD model of the solar still can significantly improve means for optimization of the solar still structure because it reduces the need for conducting large amount of experiments. Therefore, the main purpose of this study is presenting a multi-phase, three-dimensional CFD model, which predicts the performance of the solar still without using any experimental measurements, depending on the CFD solar radiation model. Simulated results are compared with experimental values of water and glass cover temperatures and yield of fresh water in climate conditions of Sheben El-Kom, Egypt (latitude 30.5° N and longitude 31.01° E). The simulation results were found to be in acceptable agreement with the experimental measured data. The results indicated that the daily simulated and experimental accumulated productivities of the single-slope solar still were found to be 1.982 and 1.785 L/m2 at a water depth of 2 cm. In addition, the simulated and experimental daily efficiency were around 16.79% and 15.5%, respectively, for the tested water depth.publishedVersionPeer reviewe

Experimental study with thermal and economical analysis for some modifications on cylindrical sector and double slope, single basin solar still

Solar stills are considered one of the most thermally eco-friendly and promising solutions for producing potable water in sunny and arid regions. However, they suffer from a disadvantage in terms of their low productivity. Therefore, this study aims to investigate the performance of cylindrical sector solar stills and compare them with double-slope solar stills. The study also presents the enhanced performance of a thermo-economic system by integrating cost-effective and readily available materials. The experiments were conducted in Egyptian climate conditions, with a water depth of 2 cm in the stills basin, using different materials. Under the same operating conditions, the results showed that the accumulated productivities of the cylindrical sector solar stills (CSSS) and double slope solar stills (DSSS), using black fiber and black dye, were 3514 ml/m2 and 3029 ml/m2, respectively, representing an increase of 16.01%. Furthermore, the daily thermal efficiency of the CSSS and DSSS, using black fiber and black dye, were 30.42% and 26.32%, respectively, showing an increase of 15.58%. The cost per liter (CPL) of potable water produced by CSSS, using black dye with black natural-fiber, was approximately 0.0119 US$/L, while it was 0.0137 US$/L for DSSS. Additionally, the payback periods for CSSS and DSSS were 92 days and 106 days, respectively. In all scenarios studied, the daily accumulated productivities and thermal efficiency of CSSS were greater than those of DSSS

High single scrotal-incision orchidopexy as the standard technique in infants aged 6–24 months

Objective: To prospectively investigate the effectiveness of high single scrotal-incision orchidopexy (HSSIO) for palpable undescended testis (PUDT) in infants aged 6–24 months. Patients and methods: From March 2012 to July 2014, 46 age range-restricted (6–24 months) infants with 57 PUDT underwent HSSIO after obtaining written consent from their parents. The exclusion criteria were ectopic, retractile testes and recurrent cases. All infants were examined before surgery in the outpatient department and after anaesthesia induction immediately before surgery. All infants had general anaesthesia with a caudal block. The operative time, intraoperative and postoperative complications, and follow-up of the infants at 0.5, 3 and 6 months were recorded and analysed. Results: The mean (SD; range) operative time was 23.45 (3.28; 18–29) min. A hernia sac was found in 39 (68.4%) UDTs. For postoperative complications, only one infant developed a scrotal haematoma that was managed conservatively. The procedure was successful in 56/57 PUDT (98%). An auxiliary procedure was needed in one case, to obtain more length of the cord by extension of the incision to the external ring. Conclusion: HSSIO is a safe and feasible technique, with many benefits, and as such should be considered as the standard technique for orchidopexy in infants aged 6–24 months

Bipolar plasma kinetic enucleation of non-muscle-invasive bladder cancer: Initial experience with a novel technique

Objective: To assess the effectiveness and safety of bipolar plasma kinetic energy for en bloc enucleation of non-muscle-invasive bladder cancer (NMIBC). Patients and methods: In all, 46 patients diagnosed with suspected NMIBC were included. All patients were diagnosed using ultrasonography, computed tomography, and diagnostic cystoscopy, and then underwent bipolar plasma kinetic enucleation of bladder tumour (PKEBT). At the end of the procedure, all patients had a single-dose (40 mg in 40 mL saline) intravesical installation of mitomycin C (<6 h after bipolar PKEBT). Follow-up diagnostic cystoscopy was performed at 3, 6, and 12 months. Results: The mean (SD) enucleation time was 17 (5.4) min, operative time was 27.9 (11.4) min, haemoglobin drop was 1.3 (0.9) g/dL, postoperative irrigation time was 1.7 (2.3) h, and hospital stay was 35.4 (13) h. There was intraoperative bleeding in three patients, with one requiring blood transfusion. There were no other perioperative complications. At the 1-month follow-up, six (13%) patients were diagnosed with residual tumour and underwent repeat bipolar PKEBT. The overall recurrence rate at 12 monthsâ follow-up was 15.2%. Conclusion: Bipolar PKEBT is an effective procedure for managing NMIBC, as it preserves the entire lamina propria and detrusor muscle in well-intact specimens, with negligible perioperative complications. Keywords: NMIBC, non-invasive muscle bladder cancer, PKEBT, plasma kinetic enucleation of bladder tumour, TUR, transurethral resectio

Mathieu technique with incision of the urethral plate versus standard tubularised incised-plate urethroplasty in primary repair of distal hypospadias: A prospective randomised study

Objective: To compare outcomes of the Mathieu incised-plate (Mathieu-IP) technique vs the standard tubularised incised-plate (TIP) technique for primary management of distal hypospadias. Patients and methods: Between April 2012 and August 2015, 66 patients (aged 15–60 months) with primary distal hypospadias were randomly allocated to two groups. Group 1 included 34 patients who underwent Mathieu-IP repair and Group 2 included 32 patients managed using the TIP technique for primary management of distal hypospadias. Postoperatively, all patients were examined weekly up to 1 month and then at 3 and 6 months. Perioperative data, complications and outcomes of both procedures were statistically analysed and compared. Results: There were no statistically significant differences in patient demographics between the groups at baseline. There was no statistically significant difference in the mean (SD) operative time between Groups 1 and 2, at 95 (7.6) and 91.2 (8.1) min, respectively. There was no statistically significant difference in the shape of the urine stream at micturition or the neomeatus between the groups postoperatively. The rate of postoperative fistula was significantly higher in Group 2 (TIP) compared to Group 1 (Mathieu-IP), at 18.7% vs 2.9% (P = 0.004). There was no postoperative meatal stenosis in Group 1, which did occur in five patients (15.6%) in Group 2 (P = 0.002). Conclusion: The Mathieu-IP technique appeared to be better than the standard TIP technique with regard to postoperative fistula formation and meatal stenosis, and with acceptable cosmesis

Does Preheating Resin Cements Affect Fracture Resistance of Lithium Disilicate and Zirconia Restorations?

This paper assesses the impact of preheating of adhesive cement on the fracture resistance of lithium disilicate and zirconia restorations. Methods: A total of 80 human maxillary premolar teeth were assigned into 8 groups (n = 10) according to material type (either lithium disilicate or zirconia) and type of resin cement (either LinkForce or Panavia SA) with preheating temperature at 54 °C or at room temperature (25 °C). Teeth were prepared and restored with either lithium disilicate or zirconia restorations. After cementation, specimens were thermal cycled (10,000 cycles, 5 °C/55 °C), then load cycled for 240,000 cycles (50 N). Each specimen was statically loaded until fracture and the load (N) at fracture was recorded, then the failure mode was detected. Statistical analysis of data was performed (p ≤ 0.05). Results: There was no significant difference (p = 0.978) in fracture mean values between LinkForce and Panavia SA. Statistically significant difference (p = 0.001) was revealed between fracture resistance of lithium disilicate restorations cemented with LinkForce at 25 °C and at 54 °C; however there was no significant difference (p = 0.92) between the fracture resistance of lithium disilicate restorations cemented with Panavia SA used at 25 °C and at 54 °C. Regarding the interaction between ceramic material, cement type, and cement preheating, there was no significant effect (p &gt; 0.05) in fracture resistance. The cement type does not influence the fracture resistance of ceramic restorations. Preheating of resin cement has negatively influenced the fracture resistance of all tested groups, except for lithium disilicate cemented using LinkForce cement