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This study aims to evaluate the influence of pulsed cathodic protection on calcareous deposit formation on structures submerged in the synthetic sea water.

Chronoamperometric and C_HF methods have been used to evaluate the influence of pulsed cathodic protection on decreasing the required cathodic current for protection and also decreasing the surface coverage. The morphology of the formed deposits was evaluated using scanning electron microscopy. Chemical analyses of the formed deposits were performed using energy dispersive X‐ray spectrometer and X‐ray diffraction.

It was observed that pulse frequency influenced both the structure and the composition of the deposits. The most compact aragonite layer was obtained at high frequencies and at a high off‐time. It was clearly shown that by applying currents with less than 100 Hz frequency, the deposits formed on the sample involved CaCO₃ (aragonite) and Mg(OH)₂ (brucite). However, the kinetics of deposits formed when applying pulse current have been improved, compared to deposits formed by conventional cathodic protection. The reason is that large electrode overpotential favors nucleation through a decrease in the energy of nucleus formation. On the other hand, by intensive decrease of surface potential, repulsion of aggressive anions such as SO₄²⁻ and Cl⁻ occurs. These anions inhibit the formation of aragonite deposits.

In order to have a better investigation of electrodeposition processes in the shorter time, the use of more advanced techniques and analysis methods such as XPS is recommended. Furthermore, EHD techniques could be used for measurements of thickness of the layers.

The pulsed cathodic protection method is a relatively new method for the protection of buried and submerged structures. Recently, many researches have investigated that the influence of this technique on increasing the throwing power, decreasing interference effects on neighboring structures and increasing the uniformity of current distribution under cathodic protection.

Very little attention has been paid in the past to the effect of pulsed CP on deposit formation. The present paper, therefore, contributes useful understanding of the mechanism and advantages of such deposits in improving the effectiveness and lowering the operational cost of cathodic protection in use on offshore structures.

The purpose of this paper is to optimize the fusion zone grain size and hardness using Hooke and Jeeves Algorithm.

Experiments are conducted as per four factors, five levels response surface method based central composite design matrix. Empirical relations for predicting grain size and harness are developed. The effect of welding variables on grain size and hardness are studies. Grain size and hardness are optimised using Hooke and Jeeves Algorithm.

The developed empirical relations can be effectively used to predict grain size and hardness values of micro plasma arc welded Inconel 625 sheets. The values of grain size and hardness obtained by Hooke and Jeeves Algorithm matches with experimental values with great accuracy.

The developed mathematical models are valid for 0.25 mm thick Inconel 625 sheets only.

In the present paper only four important factors namely peak current, back current, pulse rate and pulse width are considered, however one may consider other parameters like plasma gas flow rate, shielding gas flow rate, etc.

The present work is very much useful to sheet metal industries manufacturing metal bellows, diaphragms, etc.

The status of welding process is difficult to monitor because of the intense disturbance during the process. The purpose of this paper is to use multiple sensors to obtain information about the process from different aspects and use multi‐sensor information fusion technology to fuse the information, to obtain more precise information about the process than using a single sensor alone.

Arc sensor, visual sensor, and sound sensor were used simultaneously to obtain weld current, weld voltage, weld pool's image, and weld sound about the pulsed gas tungsten‐arc welding (GTAW) process. Then special algorithms were used to extract the signal features of different information. Fuzzy measure and fuzzy integral method were used to fuse the extracted signal features to predict the penetration status about the welding process.

Experiment results show that fuzzy measure and fuzzy integral method can effectively utilize the information obtained by different sensors and obtain better prediction results than a single sensor.

Arc sensor, visual sensor, and sound sensor are used in pulsed GTAW at the same time to obtain information, and fuzzy measure and fuzzy integral method are used to fuse the different features in welding process for the first time; experiment results show that multi‐sensor information can obtain better results than single sensor, this provides a new method for monitoring welding status and to control the welding process more precisely.

Dielectric barrier discharge (DBD) is widely used in the treatment of skin disease, surface modification of material and other fields of electronics. The purpose of this paper is to design a high-performance power supply with a compact structure for excimer lamps in electronics application.

To design a high-performance power supply with a compact structure remains a challenge for excimer lamps in electronics application, a current-source type power supply in a single stage with power factor correction (PFC) is proposed. It consists of an excitation voltage generation unit and a PFC unit. By planning the modes of the excitation voltage generation unit, a bipolar pulse excitation voltage with a high rising and falling rate is generated. And a high power factor (PF) on the AC side is achieved by the interaction of a non-controlled rectifier and two inductors.

The experimental results show that not only a high-frequency and high-voltage bipolar pulse excitation voltage with a high average rising and falling rate (7.51GV/s) is generated, but also a high PF (0.992) and a low total harmonic distortion (5.54%) is obtained. Besides, the soft-switching of all power switches is realized. Compared with the sinusoidal excitation power supply and the current-source power supply, the proposed power supply in this paper can take advantage of the potential of excimer lamps.

A new high-performance power supply with a compact structure for DBD type excimer lamps is proposed. The proposed power supply can work stably in a wide range of frequencies, and the smooth regulation of the discharge power of the excimer lamp can be achieved by changing the switching frequency. The ideal excitation can be generated, and the soft switching can be realized. These features make this power supply a key player in the outstanding performance of the DBD excimer lamps application.

The purpose of this paper is to introduce a theoretical investigation of the pulse‐cathodic protection (PCP) systems to show how they behave under different operating conditions. The effectiveness of the PCP system also is highlighted for a typical large‐scale configuration. The principal technical objectives of this paper are to answer three questions: Are the PCP systems effective in the desert fields? Although they have been approved, what is the reason for their lack of effectiveness in some coastal areas? What are the operation recommendations for the currently installed PCP systems and their future application?

The factors affecting the cathodic protection of well casings have been investigated theoretically by using a 3D field approach software package current distribution, electromagnetic fields, grounding and soil structure analysis. Cathodic interference with nearby well casings has been investigated thoroughly because corrosion of this kind is more serious than the anodic type. The performance of PCP systems has been analyzed with respect to obtaining better protection‐current distribution along the protected well casing at reduced anode current, together with reduced stray current (corrosion) at any nearby unprotected structure(s).

For uncoated well casings, protection current pulses are attenuated significantly and are smoothed out to be pure direct current after about 10 percent of the well‐casing buried length. High‐magnitude stray current can be found affecting any switched‐off well casings and hence they can be corroded faster from the top part than unprotected/remote wells, as are deeper well casings that may sustain considerable localized corrosion attack on the upper portions of the casing. Without the formation of a natural protective coating with high resistivity, the PCP system becomes malfunctioning, i.e. its performance becomes very similar to that of the conventional cathodic protection (CP) systems. This effect has been confirmed by field measurements in Oman, where magnesium hydroxide is minimally formed (in desert areas).

In reality, some of the PCP modules at the same station can have a slight deviation in the operating frequency and/or voltage. It is planned, therefore, that the investigation will be extended to simulate such cases and take into account the effect of multi‐layer soils.

Knowing the performance of PCP systems for protecting deep well casings is a critical issue for the oil industry.

The paper provides a sound basis on which oil producers can take decisions about the future application of the PCP systems, optimize their performance, and introduce application restrictions by studying all factors that affect PCP performance. The effectiveness of PCP in desert (sandy/rocky) soil, where calcium‐carbonate deposition predominates over magnesium‐hydroxide formation, has proven to be very similar to that of a conventional CP system. The reliability of artificial oil‐lifting systems will be increased by reducing oil production losses (“oil deferment”) and the rig mobilization, which has very high rent cost.

Welding process is a complicated process influenced by many interference factors, a single sensor cannot get information describing welding process roundly. This paper simultaneously uses different sensors to get different information about the welding process, and uses multi‐sensor information fusion technology to fuse the different information. By using multi‐sensors, this paper aims to describe the welding process more precisely.

Electronic and welding pool image information are, respectively, obtained by arc sensor and image sensor, then electronic signal processing and image processing algorithms are used to extract the features of the signals, the features are then fused by neural network to predict the backside width of weld pool.

Comparative experiments show that the multi‐sensor fusion technology can predict the weld pool backside width more precisely.

The multi‐sensor fusion technology is used to fuse the different information obtained by different sensors in a gas tungsten arc welding process. This method gives a new approach to obtaining information and describing the welding process.

The paper outlines the application of a unique Pulsed Current technique to the Acid Copper Electrolyte used in the PCB industry. It discusses some of the inherent difficulties associated with conventional DC plating and how these pulsing techniques can overcome them to enable the production of a higher quality product despite the ever increasing demands being placed on manufacturers for better distribution and through‐hole plating.

The purpose of this paper is to investigate the effect of pulsed magnetic field (PMF) with different duty cycles on the melt flow and heat transfer behaviors during direct-chill (DC) casting of large-size magnesium alloy billet and find the appropriate range of duty cycle.

A transient two-dimensional mathematical model coupled electromagnetic field, flow field and thermal field, is conducted to study the melt flow and temperature field under PMF and compared with that under the harmonic magnetic field.

The results reveal that melt vibration and fluctuation are generated due to the instantaneous impact of repeated thrust and pull effects of Lorentz force under PMF. The peak of Lorentz force decreases greatly with the increasing duty cycle, but the melt fluctuation region is expanded with higher duty cycle, which accelerates the interior melt velocity and reduces the temperature gradient at the liquid-solid interface. However, PMF with overly high duty cycle has adverse effect on the melt convection and limited influence on the interior melt. A duty cycle of 20% to 50% is a reasonable range.

This paper can provide guiding significance for the setting of duty cycle parameters on DC casting under PMF.

There are few reports on the effect of PMF parameters during DC casting with applying PMF, especially for duty cycle, a parameter unique to PMF. The findings will be helpful for applying the external field of PMF on DC casting.

Super 304HCu super austenitic stainless steel tubes containing 2.3 to 3 (Wt.%) of copper (Cu) is used in superheaters and reheater tubings of nuclear power plants. In general, austenitic stainless steels welded by conventional constant current gas tungsten arc welding (CC-GTAW) produce coarse columnar grains, alloy segregation and may result in inferior mechanical properties. Pulsed current gas tungsten arc welding (PC-GTAW) can control the solidification structure by altering the prevailing thermal gradients in the weld pool.

Super 304HCu tubes of Ø 57.1 mm and the wall thickness of 3.5 mm were autogenously welded using CC and PC-GTAW processes. Joints are characterized using optical microscopy, electron microscopy, energy dispersive spectroscopy and electron backscatter diffraction (EBSD) techniques. Hot tensile properties of the weld joints were evaluated and correlated with their microstructural features.

Current pulsing in GTAW has resulted in minimal eutectic film segregation, lower volume % of delta ferrite and appreciable improvement in tensile properties than CC-GTAW joints.

The EBSD boundary map and inverse pole orientation map of Super 304HCu weld joints evidence the grain refinement and much frequent high angle grain boundaries achieved using weld current pulsing.

The purpose of this paper is to investigate the feasibility of using a pulsed Tungsten inert gas arc to fully melt and consolidate stainless steel powder onto a stainless steel substrate. The technology aims to bridge the gap between selective laser sintering or laser melting and wire fed weld deposition by providing good quality and better resolution at a lower cost.

Current settings between 5 and 30 A and frequencies between 0 and 200 Hz were used to consolidate stainless steel powder onto a substrate. Results were catalogued based on surface roughness using white light interferometery to develop a process map.

Velocity independent thresholds of current (17 A minimum) and frequency (20 Hz minimum) were found, with better quality achieved at higher pulse frequencies. The microstructure of the samples were examined showing grain sizes of ≈3 μm for equiaxed grains and up to 20 μm for the columnar grains. Vickers hardness measurements showed only a 20 point average hardness increase in the HAZ compared to the substrate.

The study showed that although it was possible to deposit stainless steel tracks, it was not possible to reduce the track resolution to less than 400 μm at any of the process settings.

The research aims to investigate the use of a readily available, low cost, heat source to consolidate metal powder. The suitability of such a heat source for rapid prototyping is investigated using a variety of objective tests to provide a balanced view of its capabilities and limitations.