Pipeline failure evaluation and prediction using failure probability and neural network based on measured data

The chemical corrosion of metals in large industries such as oil and gas is a fundamental and costly problem. Gas transmission and distribution pipes and the other structures submerged in the soil and in an electrolyte, according to the existing conditions and according to the metallurgical structure, are corroded, and after a period of work, they disrupt an active system and process and lead to loss. The worst corrosion that occurs for metals embedded in the soil is where there are stray electric currents. Based on this, the cathodic protection of metal pipes is known as the most effective protection method to prevent the corrosion of structures buried in the ground, which is widely used to protect the corrosion distribution and transmission pipes of gas, oil, and water. In gas networks, current and voltage measurements for cathodic protection are carried out and recorded in specific periods according to the standards approved by the National Gas Company. The effect of stray currents on the obtained results is significant. The reason for this is that the available data is recorded as a time series, and as a result, the critical value of this time series will significantly impact the remaining life of the gas pipelines. Therefore, the purpose of this article is to investigate the stray currents effect on failure rate using normal probability distribution. In the following, the estimation of the remaining useful life of gas pipelines under cathodic protection is obtained using neural networks and compared with the results of the failure probability to check the accuracy of the results. According to the data history of the equipment, the amount of failure and the remaining useful life of the gas pipelines will be obtained.

Dioxins and furans releases in Iranian mineral industries

In this project, emissions of Poly-Chlorinated Dibenzo-p-Dioxins and Dibenzo-Furans (PCDD/Fs) were investigated and estimated for selected Iranian mining and ore processing industries, such as integrated iron & steel plant, primary production of aluminium and copper metal, and the production of cement. As a first step of this study the annual emission of PCDD/Fs was estimated at 120gTEQannum(-1) on the base of the UNEP standardised Toolkit for identification and quantification of dioxin and furan releases. Steel and cement were identified as major emission sources and earmarked for further scrutiny. For that reason, filter dust arising in these plants was sampled and analysed, as well as all raw materials employed. After extraction and clean-up according to standard methods, the resulting liquid samples were analysed and quantified by HRGC-HRMS. Complementary analyses using methods such as XRF, TGA/DTA were performed and the emission results statistically evaluated, in order to put PCDD/F emissions in perspective. It is concluded that the dioxins load of cement dust is unusually low, following the low carbon in raw materials, the use of natural gas as a fuel and the absence of waste incineration. Also the production of iron by direct reduction of ore is a low dioxins process; dioxin loads in dust are as usual - correlated with the presence of catalytic metals. Loss on ignition and chlorine are anti-correlated with the main earth elements and with sulphur oxides.

Confirmation of hydrazone formation in HYNIC-peptide conjugate preparation, and its hydrolysis during labeling with 99mTc

Because of its monodenticity, 6-hydrazinopyridine-3-carboxylic acid (HYNIC) is of interest as a bifunctional chelator for labeling peptide with (99m)Tc. Here, we confirm the formation of hydrazone in HYNIC-conjugated peptide. The preparative HPLC was used to purify the HYNIC conjugated somatostatin-based peptide and the result showed two peaks, even after two consecutive purifications. Analysis of these peaks by mass spectrometry indicated the presence of hydrazone, produced during preparation conjugate. Further, we have shown that presence of hydrazone really does not matter because under (99m)Tc-labeling conditions, hydrazone is hydrolyzed back to HYNIC that then chelates (99m)Tc. A HYNIC-peptide conjugate freeze-dried kit was also prepared in a mildly acidic or neutral condition with a final pH of 6-7. The kit was then labeled by (99m)Tc and incubated in 100 degrees C for 10min, and a labeling yield of >95% was obtained.

Direct labelling of octreotide with 99mTc: effect of different concentration of reducing agents and amount of sodium pertechnetate on radiolabelling efficiency

Octreotide, a synthetic analog of natural hormone somatostatin, was labelled with 99mTc. Labelling was accomplished by reduction of the cysteine bridge, which provided sulfhydryl groups for chelating with 99mTc. Sodium ascorbate and sodium dithionite in different concentrations were used as reducing agents. Different amounts of sodium pertechnetate were used for labelling of peptide. When the mass ratio of peptide and sodium ascorbate was 1:100 and the final concentration of dithionite in the labelling vial was 0.2-0.4 microg/microl with 0.18-1.48 GBq sodium pertechnetate more than 80% radiolabelling efficiency was confirmed by RP-HPLC, ITLC-SG and C18 Cartridge analysis. The stability of the 99mTc-peptide bond was evaluated by human serum challenge and that showed the stability was 90% after 4h.