Inhibition of atmospheric corrosion of mild steel by sodium benzoate treatment

The objective of this study was to evaluate the effectiveness of sodium benzoate as an inhibitor to slow down or prevent atmospheric corrosion/discoloration of the local mild steel during storage in the Arabian Gulf region. Test specimens were prepared from locally produced reinforcing steel products. The inhibitor solution was applied on steel specimens at a concentration of 100 mM for 1 day at room temperature. Wooden exposure racks were used to hold as-received and inhibitor-treated specimens during atmospheric exposure for different periods. Corrosion was evaluated through weight loss determination and electrochemical technique. As expected, the Arabian Gulf atmosphere was corrosive on the as-received local mild steel. On the other hand, treatment of steel with sodium benzoate lowered its corrosion rate during initial days of its exposure to atmosphere. However, atmospheric corrosion inhibition performance of sodium benzoate deteriorated with exposure time after 30 or more days of atmospheric exposure, and the corrosion rates of sodium benzoate-treated specimens reached that of the unprotected specimens at the end of 90 days of atmospheric exposure.     

Performance failure analysis of EDFA cascades in optical DWDM packet-switched networks

A simple and comprehensive technique to determine the probability that a cascade of erbium-doped fiber amplifiers (EDFAs) may be driven into unacceptable regimes of bit error rate (BER) and/or gain levels is presented. This technique allows network designers to determine the tolerances by which the signal power levels may deviate from their predesigned average values and still give acceptable gain variances and BERs at the receiver. We show that even in the signal power range well above the receiver sensitivities (-38 dBm/ch) where the gain spread is not significant, the corresponding spread in BER due to random arrival of packets might result in unacceptable performance. We show for typical levels of operation, the BER temporarily (for about 3 /spl mu/s) deviates to below 10/sup -9/ (10/sup -15/) with a probability of 10/sup -3/ (10/sup -2/), for 100 (64) channels. We show that the gain spread for a single EDFA can be negligible for a range of signal and pump powers at a given average gain.     

Fuzzy multiattribute evaluation of R&D projects using a real options valuation model

R&D project selection decision is very important in two ways. First, in many organizations, R&D budget represents huge investment. Project selection decisions could be thought with the strategic objectives and plans of the firm. Second, R&D projects' organizational returns are multidimensional in nature and risky in terms of projected outcome. Real options approach helps to calculate this risky side of the selection process. This paper considers that multidimensional side of the R&D project selection process. Another consideration is the vagueness in the evaluation process. The fuzzy analytic hierarchy process, which takes monetary (fuzzy real option value) and nonmonetary (capability, success probability, trends, etc.) criteria into account, is used to make this selection among alternative R&D projects. A real case study is given to illustrate the application of the proposed approach. © 2008 Wiley Periodicals, Inc.     

Prioritization methodology of dangerous substances for water quality monitoring with scarce data

Monitoring and control of dangerous substances discharged into receiving waters have attracted more attention lately. Since it is not possible to analyze every single substance, a prioritization methodology is needed for the selection of those to be monitored. Existing well-developed models require significant amount of data for reliable outcomes. This paper presents a methodology to prioritize the dangerous substances having adverse effects on freshwaters in Turkey, where data are scarce. Such a methodology will also serve as a solid model for other countries with limited background data. The adopted methodology enabled the elimination of chemicals to generate a candidate list composed of 608 substances among more than 5000 substances. Further screening and prioritization were conducted using different assessment methods (i.e., Total Hazard Value, Total Impact Value, Combined Monitoring-based, and Modelling-based Priority Setting) to obtain a proposed Final Candidate Specific Pollutants List of 150 dangerous substances. The proposed Candidate National Pollutant List of Turkey was established by combining 45 priority pollutants of the European Union with a list of candidate specific pollutants. According to the outcomes of this study, monitoring and controlling of 195 dangerous substances in freshwaters are recommended. Further detailed studies should be conducted in order to observe the actual levels of these dangerous substances in freshwaters followed by a review of the monitoring list accordingly. Moreover, further revisions might be required in the proposed list due to some possible versatile conditions in terms of sampling points (i.e., change in the location of industries).     

Synthesis of novel acrylic modified water reducible alkyd resin: Investigation of acrylic copolymer ratio effect on film properties and thermal behaviors

New four‐component water reducible acrylic modified alkyd resins that are based on 1,3‐propanediol and contain different ratios of acrylic copolymer (AC) were synthesized by using a novel four‐stage fatty acid method. The final content of solids in the water reducible acrylic modified alkyd resins was 60% by weight. After the modified alkyd resin films were cured at 150°C for 1 h, it was observed that the use of AC as the modifier component had improved their physical and chemical surface coating properties and thermal behaviors. Experimental results show that the optimum AC ratio is 40% of the equivalent amount of AC to alkyd resin. Low‐volatile organic compounds (VOC) content water reducible acrylic modified alkyd resins yielded soft and flexible films with high chemical/thermal resistance, suitable for manufacturing of surface coating binders. POLYM. ENG. SCI., 56:947–954, 2016. © 2016 Society of Plastics Engineers