Reducing the Effects of Water Hammer Phenomenon in Pipelines by Changing the Closing Rate of Line Break Valve (LBV)

Line break valves in pipelines are using to prevent environmental hazards caused by the entry of the fluid into the surrounding. The operation of these valves leads to sudden changes in pressure and velocity, resulting in the occurrence of the water hammer phenomenon. The water hammer pressure will cause serious problems such as the destruction of pipelines and transmission line equipment and tools. Due to the salinity of water, when a fracture occurs, the amount of water that enters the surrounding is environmentally essential, so the use of several LBVs is vital. This paper investigated a water transmission line with a total length of 337 km that transfers saline water from Khoor Moosa to Azadegan plain. This study discussed the closing of the valve at different rates and the solution to reduce its destructive effects. WaterGEMS V8i software and Hammer V8i software are respectively using to perform a steady flow simulation and damping flow analysis for this phenomenon. The results obtained from the steady-state flow simulation is the initial conditions in the damping flow calculations. Then, by reducing the closing rate of the valve in 6 different scenarios, the volume of air chambers decreased. Finally, the results led to creating a linear relationship between the valve closing rate and the capacity of the air chamber. The optimal model for this rate depends on reducing the construction cost as well as the environmental hazards caused by discharged water.

Effectiveness and Safety of Bedaquiline-containing Regimens for Treatment on Patients With Refractory Rifampicin/multidrug-resistant Tuberculosis: A Retrospective Cohort Study in East China

Objective: To compare the effectiveness and safety of bedaquiline-containing and bedaquiline-free regimens for treatment of patients with refractory rifampicin-resistant/multidrug-resistant tuberculosis (RR/MDR-TB).Methods: Patients with refractory RR/MDR-TB receiving bedaquiline-containing regimens (bedaquiline group, n=102) and bedaquiline-free regimens (non-bedaquiline group, n=100) were included in this retrospective historical control study across East China. The culture conversion, end-of-treatment outcomes, cavity closing rate, and adverse events (AEs) were compared between the two groups. Univariate and multivariate analyses were performed to identify independent predictors of treatment success and culture reversion.Results: The baseline characteristics of the patients were well balanced between the two groups. The culture conversion rates in the bedaquiline group at month 3 (89.2% vs. 66.0%), month 6 (90.2% vs. 72.0%), month 9 (91.2% vs. 66.0%), and month 12 (94.1% vs. 65.0%) were all significantly higher than those in the non-bedaquiline group (all p<0.001). Similar results were observed in the cavity closing rate at month 9 (19.6% vs. 8.0%, p=0.017) and month 12 (39.2% vs. 15.0%, p<0.001). Patients receiving bedaquiline-containing regimens had more treatment success than those receiving bedaquiline-free regimens (p<0.001; cure rate, 69.6% vs. 45.0%; complete the treatment, 22.5% vs. 18.0%; treatment success, 92.2% vs. 63.0%). The use of bedaquiline was identified as an independent predictor of both treatment success (OR=7.356, 95% CI: 2.920–18.530, p<0.001) and culture reversion (OR=0.124, 95% CI: 0.035–0.452, p<0.001). AEs were similarly reported in 26.5% of patients in the bedaquiline group and 19.0% in the non-bedaquiline group (p=0.206).Conclusions: Bedaquiline-containing regimens resulted in better treatment outcomes and similar safety relative to bedaquiline-free regimens for patients with refractory pulmonary RR/MDR-TB.

A Comparative Evaluation of Rate of Space Closure Between Newer Generation Ceramic Brackets and Conventional Straight Wire Appliance

Background: With the emerging concept of aesthetics in orthodontics, ceramic brackets play a major role especially in the anterior region of the dental arch. However, the duration of the orthodontic treatment is one of the most important issues in treating patients with ceramic brackets. Objectives: This study is conducted to compare space closing rate between conventional MBT and Symetri ClearTM bracket systems. Methods: This study is comprised of 18 subjects who were equally separated into two groups. The first group was treated with conventional MBT pre-adjusted bracket and the second group with Symetri ClearTM brackets. Space closure was performed via 0.019 × 0.025 inch stainless steel wires using 9-mm nickel-titanium Sentalloy coil springs with a constant force of 150 g. The distance between the distal of the first molar buccal tube and the mesial of the canine bracket was measured by a digital caliper. The difference of the first and last values was determined to assess the sheer quantity of space closure. The value was then divided by the number of months during which the space closure was carried out to examine the ratio of space closure in mm per month. For the statistical analysis we used paired t test as well as independent t test and the P-value > 0.05 was deemed significant. Results: The MBT group showed a 0.85 mm/appointment retraction rate while the Symetri ClearTM bracket group had a 0.83 mm/appointment retraction rate. The difference in space closing between MBT and Symetri ClearTM groups was not statistically and clinically significant (P-value > 0.05). Conclusions: As the rate of space closure was almost similar in the two types of brackets, we can use Symetri ClearTM brackets instead of MBT brackets without any concern about the duration of treatment and use the esthetic benefits of these brackets simultaneously.

Pengaruh Profitabilitas dan Leverage terhadap Harga Saham Perusahaan Manufaktur di Bursa Efek Indonesia

This study aimed to determine the relationship between managerial ownership, leverage, and profitability to the stock prices of manufacturing companies listed on the Stock Exchange for the period 2015 to 2017. Profitability is proxied by Return on Equity (ROE), while leverage is proxied by Debt to Equity Ratio (DER). The stock price applied was the closing rate of the year-end stock. Sampling was done by using purposive sampling method. The subject of the study was 30 manufacturing companies with a total of 90 observations. The data analysis utilised multiple regression analysis with the help of the SPSS program. Based on the results of the study, it was found that the profitability had a significant effect on stock prices, and leverage did not affect stock prices. Together, profitability and leverage did not have a significant effect on stock prices. Thus, the company must pay more attention to the profitability of the business in order to maintain a good price of the stock and to attract investors.

Fixing the Bugs in Software Projects from Software Repositories for Improvisation of Quality

Background: The study of bugs that are reported and close may indicate the growth and working of a software project. It may also indicate the quality of the project. Methods: As software projects grow, the number of bugs reported generally increases each year. To maintain quality, the developers have to resolve and close these increasing numbers of bugs. Results: The present paper discusses the relations between bugs being reported and bugs being closed. It also discusses some parameters related to the study of bugs. In this paper, new parameters have been introduced that help in the improvement of quality and this is the novelty of paper. Conclusion: The research mainly covers the problem of finding the relation of collaborative growth with the quality of software. The paper also covers improvements in parameters like the rate of bug fixing. It also discusses the significance of these parameters. We have suggested a new parameter called the bug closing rate. And this can be calculated in two ways.

Effects of perfluorocarbon liquids in macular hole retinal detachment treatment

Objective: This study aims to evaluate the clinical efficacy and visual function prognosis of macular hole retinal detachment treatment for high myopia by inverting the internal limiting membrane to overlay the macular hole with the assistance of perfluorocarbon liquids. Methods: A total of 55 high myopia patients, who received macular hole retinal detachment treatment from 2013 to 2016, were included in this study. Among these patients, 38 patients were assigned to the first group and 17 patients (perfluorocarbon liquids) were assigned to the second group. The second group was further divided into two subgroups, according to the overlaying layer number of the internal limiting membrane valve: A group (multiple layers) and B group (single layer). Results: The success rate of the internal limiting membrane inversion and overlaying on the macular hole was 23.68% and 100% in the first and second group, respectively. The differences in macular hole closing rate and postoperative best-corrected visual acuity between these two groups were statistically significant ( p < 0.05). Furthermore, the differences in macular morphology recovery between the A and B groups were also statistically significant ( p = 0.004 < 0.05). Conclusion: Perfluorocarbon liquids play a positive role in the operation process of the internal limiting membrane.

The Double Mediating Effect of Start-Up Motive and Start-Up Spirit between Start-Up Opportunity Awareness and Expected Outcome af a Start-Up

The purpose of this study was to investigate the double mediating effect of start-up motive and start-up spirit between start-up opportunity awareness and expected outcome of a start-up. The subjects of this study were 251 employees living in Seoul, Daejeon, Chungnam, and Chungbuk in Korea. The collected data were analyzed using SPSS PC+ and PROCESS macro. Correlation analysis, reliability analysis, descriptive statistics, and mediation effect analysis were applied for data analysis. First, start-up opportunity awareness was positively correlated with start-up motive, start-up spirit, and the expected outcome of a start-up. Second, the start-up motive mediated the relationship between start-up opportunity awareness and the expected outcome of a start-up. Third, the start-up spirit mediated the relationship between start-up opportunity awareness and the expected outcome of a start-up. Fourth, start-up motive and start-up spirit both mediated the relationship between start-up opportunity awareness and the expected outcome of a start-up. Finally, based on the results of this study, the ways to overcome the low level of start-up spirit and the early closing rate of start-up were discussed

Parameterized Trade on the Futures Market on the WIG20

Research background: Market participants have been trying to forecast future price movements and create tools to facilitate making the right investment decisions since the beginning of the operation of stock exchanges. As a result, there are an increasing number of methods, tools, strategies and models to make the decision process which is becoming extremely complicated. Purpose: to maximize the simplification of trade rules and to check whether it is possible to parameterize transactions based on the length of price movements in order that the system built in this way would generate profits. Research methodology: empirical research was conducted on data from the period between 20/01/1998 and 29/06/2018 covering listing futures contracts for the WIG20. First, the length of the price movements was determined according to the closing rate, then the frequency of individual lengths of the price movements was determined so transaction parameters were fixed. Next, the parameters were optimized and the rates of return from the tested options were examined. Result: It is possible to parameterize transactions based on the length of price movements and to create a simple investment strategy which generates profits. In the audited period, the optimal length of traffic was 25 points with a simultaneous use of a profit/loss ratio of 1 : 1, 1 : 2 or 1 : 3. Novelty: an original investment strategy based on the parameterization of transactions that is based on length of price movement and profit/loss ratio.

Instantaneous sea ice drift speed from TanDEM-X interferometry

The drift of sea ice is an important geophysical process with widespread implications for the ocean energy budget, ecosystems, and marine operations. Drifting sea ice can threaten navigation routes and present a hazard for ocean vessels and maritime installations. Here, we evaluate single-pass synthetic aperture radar (SAR) interferometry (InSAR) as a tool to assess ice drift for different uses. Initial validation shows that TanDEM-X phase-derived drift speed corresponds well with drift products from a ground-based radar at Utqiaġvik, Alaska. Joint analysis of TanDEM-X and Sentinel-1 data covering the Fram Strait demonstrates that InSAR can help quantify the opening/closing rate of leads. In contrast to standard SAR-based drift algorithms deriving averaged drift velocities, single-pass InSAR enables an instantaneous assessment with advantages in the context of ice management and transportation. By evaluating sea ice drift through the Vilkitsky Strait, Russia, we identified short-lived transient convergence patterns. We conclude that InSAR enables the identification of potentially important short-lived dynamic processes otherwise difficult to observe with possible implication for engineering and sea ice modeling.

A simple explanation of biased movements of renminbi exchange rate

The central parity of the renminbi is determined by the closing rate on the previous day according to the central parity formation mechanism following the August 2015 reform. This paper develops a simple model to study how this mechanism affects the currency’s exchange rate dynamics. The central parity is shown to be under monotonic decay or growth conditional on its rate relative to the expected exchange rate determined by a generic stochastic process. Such dynamics requires the central bank to engage in vigorous intra-marginal intervention to halt currency depreciation (or appreciation). Such upward (or downward) bias will disappear if a randomizing factor subject to market conditions is incorporated into the mechanism. The analysis is consistent with the observations in the renminbi foreign exchange market, and the theories and results in the previous studies on target zones.