Solutions of Some Difference Equations Systems and Periodicity

In this article, analysis and investigation have been conducted on the periodic nature as well as the type of the solutions of the subsequent schemes of rational difference equations with a nonzero real numbers initial conditions

An experimental study on the effect of gas injection configuration on flow characteristics in high viscosity oil columns

Gas-viscous liquid bubbly and slug flow are very common in petroleum, chemical, bioengineering, polymer, and food processing. However, there is a major knowledge gap in two-phase flow research in the design of gas injectors/distributers in very high viscosity oil systems. The present study investigates the effect of gas injection methods in columns containing very high viscosity oils (i.e., realistic liquids), and more specifically using 360 Pa · s viscosity oil in a 240-mm diameter column. The effects that the radial positioning, number of gas nozzles, and their distance from each other have on the structure of the flow in viscous liquids are presented in detail. Electrical capacitance tomography (ECT) is used to extract experimental data. Void fraction, bubble velocity, frequency, liquid film thickness, and bubble length were measured and analyzed at different radial gas injection positions. It has been observed that bubble length increases significantly by 0.3 m when the injection nozzle is located next to the wall of the pipe. Bubble velocity and length also increase by 0.217 m/s and 3.6 m, respectively, with increasing gas flowrate when multiple injection points are used. Increasing the distance between the gas injection points increased bubbles' length by 1.2 m. Bubbles' velocity and frequency (at higher gas flow rate) were also increased

DRAG FORCE OF TWO SPHERES IN POWER LAW FLUIDS

The present research is concerned with studying of the drag force on two spheres moving side by side and in line in non-Newtonian liquid. Polyacryamide (PAA) solution with different concentrations (0.01, 0.03, 0.05 and 0.07)% by weight and water is used for comparison for obtaining the effect of fluid properties on the drag force. Different types of spheres stainless steel, glass and plastic with different sizes and densities were used. Within the considered range of power law index (0.6 - 1), and generated Reynolds number (1.1 -75) in power law fluid and Reynolds number (100 - 1000) for water it was found the drag coefficient increases with increasing the power law index for constant generated Reynolds number and the drag force increases with fluid density increases but it decreases with the sphere density increases

The Response of Reinforced Concrete Composite Beams Reinforced with Pultruded GFRP to Repeated Loads

This paper investigates the experimental response of composite reinforced concrete with GFRP and steel I-sections under limited cycles of repeated load. The practical work included testing four beams. A reference beam, two composite beams with pultruded GFRP I-sections, and a composite beam with a steel I-beam were subjected to repeated loading. The repeated loading test started by loading gradually up to a maximum of 75% of the ultimate static failure load for five loading and unloading cycles. After that, the specimens were reloaded gradually until failure. All test specimens were tested under a three-point load. Experimental results showed that the ductility index increased for the composite beams relative to the reference specimen by 156.2% for a composite beam with GFRP with shear connectors, 148.6% for composite beams with GFRP without connectors, and 96% for the composite beam with a steel I-section

Genetic variability, heritability and character association of grain yield and its components among selected genotypes of maize (Zea mays L.), Gezira State, Sudan

In the Sudan, the low yield of maize was mainly due to the use of low yielding land races and open-pollinated varieties. Hence, the current study was conducted to measure the extent of genotypic and phenotypic variability, genotypic performance, heritability, genotype x season interaction, and the magnitude of association among seed yield and its components of 10 maize genotypes. The experiment was carried out during the summer of 2017 and the winter of 2017/18, using a randomized complete block  design with three replicates, at the University of Gezira Farm, Wad Medani, Sudan. The characters measured were days to 50% tasseling and silking, plant and ear height, number of kernels per row and per ear, ear diameter, cob length, 100-kernels weight and grain yield. High significant phenotypic variability was detected for all the measured characters. Seasonal differences were also significant. High broad sense heritability estimates were recorded for 50% tasseling and silking and plant height while the rest of the characters showed moderate estimates. The study confirmed the fact that maize is a summer crop in central Sudan. In summer, the highest seed yield genotype was HSD 5158 (2609 kg/ha) and in winter was HSD 3538 (2285 kg/ha). Days to 50% tasseling and silking and plant height were significantly and positively correlated with yield and so recommended as selection criteria for seed yield improvement. It is recommended to grow genotypes HSD 5158 in summer and HSD 3538 in winter as well as genotypes VMH 4040, VMH 4102 and HSD 5007 in both seasons. Testing of these genotypes under different locations and seasons is suggested.              يعزى ضعف إنتاجية الذرة الشامية بالسودان لزراعة أصناف مفتوحة التلقيح وسلالات محلية ضعيفة الإنتاج. هدفت هذه الدراسة لقياس التباين الظاهري والوراثي ودرجة التوريث على المدى العريض وتفاعل الطراز الوراثي والموسم وارتباط إنتاج البذور ومكوناته. نفذت التجربة في صيف 2017 وشتاء 18/2017 بتصميم القطاعات العشوائية الكاملة بثلاث مكررات بمزرعة جامعة الجزيرة، واد مدني، السودان. الصفات التي  قيست هي : عدد الأيام لظهور 50% من الأزهار المذكرة والمؤنثة وطول النبات وارتفاع القندول وعدد بذور الصف والقندول ومحيط القندول وطول الكوز ووزن مائة حبة وإنتاج البذور. أظهرت النتائج اختلافاً معنوياً بين الطرز الوراثية لكل الصفات وفي الموسمين. تأثير الموسم كان معنوياً. سجلت قيم عالية لدرجة التوريث بالمعنى العريض لصفات 50% إزهار مذكر ومؤنث وطول النبات ولكن الصفات الأخرى أظهرت قيم وسطية. ثبت أن محصول الذرة الشامية في وسط السودان محصول صيفي. الطراز الذي أعطى أعلى إنتاجية صيفاً هو HSD 5158 (2609 كجم/هـ) وشتاءً  هو  HSD 3538 (2285 كجم/هـ). ارتبطت صفات الإزهار المؤنث والمذكر وطول النبات ارتباطاً موجباً ومعنوياً بالإنتاجية وعليه يمكن استعمالها كمؤشرات انتخاب لتحسين إنتاجية الحبوب. يوصى بزراعة الطراز HSD 5158  صيفاً والطراز HSD 3538 شتاءً والطرز VMH 4040 و VMH 4102 و HSD 5007 في الموسمين معاً. يوصى بزراعة هذه الطرز المقترحة في مواسم ومواقع متعددة لتأكيد النتائج. &nbsp

Dynamics of flow transitions from bubbly to churn flow in high viscosity oils and large diameter columns

The dynamic behaviour of the gas-liquid two phase flows and in particular the flow pattern stability and transition between the flow regimes are influenced significantly by both the properties of the liquid and gas as well as the pipe diameter. The majority of the studies reported in the literature on the dynamics of gas-liquid flow transitions focus only on low viscosity liquids (e.g. water) and small diameter pipes. In the present work a series of experiments were carried out to study the dynamics of flow transitions (bubbly to slug and slug to churn) of gas rising through very viscous oils (330 Pa s and 360 Pa s) in two large diameter columns (290 and 240 mm, respectively), using Electrical Capacitance Tomography (ECT) and pressure sensors. The experiments aimed to imitate a number of realistic flow conditions that might be encountered, for examples, in; bitumen, crude oil, viscous liquids in food processing and volcanic magmatic flows. Observation and quantification of bubbly to slug and slug to churn flow transitions for gas-high viscous liquids in large pipe diameters are presented for the first time. Flow parameters and characteristics including; void fraction, pressure gradient, Probability Density Function, structure velocity, lengths of large/Taylor bubbles and liquid slugs and the effect of liquid temperature on the void fraction and Taylor bubble lengths, were measured and analysed. It was found that transition to slug and churn flow occurs gradually. Transition to slug flow occurs at a gas superficial velocity of 0.011 m/s–0.016 m/s, while transition to churn appears in the range of 0.127–0.243 m/s in both columns

Efficacy and safety of misoprostol for intrauterine device insertion in women with no previous vaginal delivery: a systematic review and meta-analysis of randomized controlled trials

Introduction: The efficacy of misoprostol use for cervical priming before intrauterine device insertion (IUD) is controversial. This review aims to evaluate the evidence from published randomized controlled trials about the efficacy and safety of misoprostol before IUD insertion for pain relief in women with no previous vaginal delivery. Materials and methods: We searched the following electronic databases: Web of Science, Cochrane CENTRAL, SCOPUS, and PubMed for relevant studies using the following Mesh terms: (misoprostol) AND (intrauterine device OR IUD). The primary outcome was the mean pain score during insertion. Secondary outcomes included the ease of insertion score, the rate of successful IUD insertion, the rate of IUD insertion failure, and the adverse effects. Results: Ten randomized controlled trials (RCTs) (misoprostol: n=698 and placebo: n=689) were pooled in the analysis. The overall Standardized Mean Difference (SMD) of pain score did not favor either of the two groups (SMD= -0.09, 95%CI [-0.50, 0.33], p=0.007). Pooled results were highly heterogeneous (I2=93%, P<0.001). The total MD of the ease of insertion score favored the misoprostol group (MD= -1.36, 95% CI [-2.20, -0.52], p =0.002). The overall risk ratio (RR) of the number of failed insertions showed that misoprostol is associated with less IUD insertion failures compared to placebo (RR=0.55, 95% CI [0.38, 0.81], p=0.002). Finally, the overall risk showed that misoprostol is associated with more shivering, diarrhea and pelvic pain. Conclusions: Misoprostol facilitates IUD insertion in women with no previous vaginal delivery, and is associated with 50% less chance for IUD insertion failure despite inducing mild adverse effect

Can deficit irrigations be an optimum solution for increasing water productivity under arid conditions? A case study on wheat plants

Water scarcity is of growing concern in many countries around the world, especially within the arid and semi-arid zones. Accordingly, rationalizing irrigation water has become an obligation to achieve the sustainable developmental goals of these countries. This may take place via using deficit irrigation which is long thought to be an effective strategy to save and improve water productivity. The current study is a trial to evaluate the pros and cons of using 50 and 75 % of the irrigation requirements (IR) of wheat (deficit irrigations) versus 100 %IR, while precisely charting changes in wheat growth parameters, antioxidant enzymes in plant shoots and the overall nutritional status of plants (NPK contents). Accordingly, a field experiment was conducted for two successive seasons, followed a split-plot design in which deficit irrigations (two irrigations to achieve 50 % of the irrigations requirements (IR), three irrigations to attain 75 % IR, and four irrigations to fulfill 100 % IR) were placed in main plots while four different studied wheat cultivars were in subplots. Results obtained herein indicate that deficit irrigations led to significant reductions in growth parameters and productivity of all wheat cultivars, especially when using 50 % IR. It also decreased NPK contents within plant shoots while elevated their contents of proline, peroxidase, and catalase enzymes. On the other hand, this type of irrigation decreased virtual water content (VWC, the amount of water used in production on ton of wheat grains). Stress tolerance index (STI), and financial revenues per unit area were also assessed. The obtained values of grain productivity, STI, VWC and financial revenues were weighted via PCA analyses, and then introduced in a novel model to estimate the efficiency of deficit irrigations (ODEI) whose results specified that the overall efficiency decreased as follows: 50 %IR &lt; 75 %IR &lt; 100 %IR. In conclusion, deficit irrigation is not deemed appropriate for rationalizing irrigation water while growing wheat on arid soils

A Closer Look at Precision Hard Turning of AISI4340: Multi-Objective Optimization for Simultaneous Low Surface Roughness and High Productivity

This article reports an extended investigation into the precision hard turning of AISI 4340 alloy steel when machined by two different types of inserts: wiper nose and conventional round nose. It provides a closer look at previously published work and aims at determining the optimal process parameters for simultaneously minimizing surface roughness and maximizing productivity. In the mathematical models developed by the authors, surface roughness at different cutting speeds, depths of cut and feed rates is treated as the objective function. Three robust multi-objective techniques, (1) multi-objective genetic algorithm (MOGA), (2) multi-objective Pareto search algorithm (MOPSA) and (3) multi-objective emperor penguin colony algorithm (MOEPCA), were used to determine the optimal turning parameters when either the wiper or the conventional insert is used, and the results were experimentally validated. To investigate the practicality of the optimization algorithms, two turning scenarios were used. These were the machining of the combustion chamber of a gun barrel, first with an average roughness (Ra) of 0.4 µm and then with 0.8 µm, under conditions of high productivity. In terms of the simultaneous achievement of both high surface quality and productivity in precision hard turning of AISI 4340 alloy steel, this work illustrates that MOPSA provides the best optimal solution for the wiper insert case, and MOEPCA results are the best for the conventional insert. Furthermore, the results extracted from Pareto front plots show that the wiper insert is capable of successfully meeting both the requirements of Ra values of 0.4 µm and 0.8 µm and high productivity. However, the conventional insert could not meet the 0.4 µm Ra requirement; the recorded global minimum was Ra = 0.454 µm, which reveals the superiority of the wiper compared to the conventional insert

Treatment of CandidaalbicansBiofilms – Associated with Dry Socket orDenture Stomatitis by PropolisPaste

Degradation of oral health is often assumed to progress with aging. However, significantly higher total counts and greater varieties of Candida species can be detected in wearers of removable dentures compared with nondenture wearers.Poorly fitting or unhygienic dentures leads to the presence of yeast like fungi (Candidaalbicans ) attached to it, and cause inflammation. Although candidiasis is highly resistant to antifungal agents, systemic drugs usage are necessary. But the systemic use of these drugs can cause side effects like liver toxicity, drug interactions etc.Usingpropolseasantifungal by localapplication, found that it suppresses the Candida associated dry socket and denture stomatitis. The Propolispast was used in the following manner. It was applied to the fitting surface of denture, twice a day for 2 weeks. The Propolisputty was putted in dry socket after complete removal of inflammatory tissuesfrom it.The results showed pain, redness area and inflammation related stomatitis were disappear gradually after 48 hours until 2 weeks that the denture stomatitis is healing by using a Propolispast.Propolisputty treat the fungal inflammation of dry socket that gradual decreases of the pain and inflammation.After the treatment, all patientswith denture stomatitis were subjected to examination of the palatal mucosa and socket and quantitative culture of Candida from the palatal mucosa and denture fitting surface and diagnosed by three method :Germ tube.GramStain.andChromAgar medi