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Contamination of the environment by heavy metals is a phenomenon of global importance today. When present in high concentrations in the environment, heavy metals may enter the food chain from soils and result in health hazards. Accumulation in street dust is one major way through which heavy metals may find their way into soils and subsequently living tissues of plants, animals and human beings. In this paper, the magnitude and sources of some heavy metals (Cu, Mn, Fe, Cd, Pb and Zn) in street dust samples in and around Gwagwalada, Nigeria, were assessed.

Street dust samples were collected from 12 sites with and without varying levels of human activities (blacksmithing, motor repair works, metal working and fabrication, vehicular traffic and residential development) in the area and analysed by atomic absorption spectrophotometry to determine the magnitude and sources of accumulation of the above heavy metals in street dust in the study area.

The mean concentrations were found to be 210, 79, 97, 3.9, 120 and 96 μg g⁻¹ respectively, for Pb, Zn, Cu, Cd, Fe and Mn across the various sampling sites. Samples collected from sites with human activities were found to contain concentrations of the metals that are generally higher than those in background areas (without human activities). However, metal working and fabrication, and motor repair works were found to have a stronger influence on the accumulation of the metals in the dust samples than vehicular traffic.

The results indicate that, contrary to what is expected, based on the observations made in several areas by many researchers elsewhere, metal working and fabrication, and motor repair works have a stronger influence on the accumulation of the metals in the dust samples than vehicular traffic in the study area.

Provides information on heavy metal contamination of the environment in an area of Nigeria.

The purpose of this study is to suppress the temperature rise of high voltage wall bushing metal plate.

First, the authors built a model of a traditional metal plate and got the magnetic field intensity distribution by FEA tools. Optimized according to the magnetic field intensity distribution, the authors slot the traditional metal plate and embed permanent magnets in the slot. Finally, the authors got the temperature distribution diagrams of the above three cases at different current levels by FEA tools.

Slotted metal plate is beneficial to suppress magnetic induction intensity, but the improvement of the magnetic induction intensity uniformity is not obvious. The method of embedding a permanent magnet in a slotted metal plate can optimize the magnitude and uniformity of the magnetic induction intensity in the metal plate. The larger the current passing through the metal plate, the better the temperature suppression effect of the slotted metal plate and the slotted metal plate embedded in the permanent magnet.

The effect of structural factors, slotting plate and setting permanent magnets on slots on the temperature of supporting plate is studied. The paper proposes two methods, slotting metal panels and embedding permanent magnet metal panels, to solve the problems of eddy current loss and high calorific value of the panel, which is of great significance to the safety of the grid equipment.

Describes a study carried out to evaluate the accumulation of heavy metals by two different vascular aquatic plants in the artificial wetlands which were constructed for the treatment of municipal wastewater in Berlin, Germany. The studied plants were Pharagmites australis and Schoenoplectus lacustris. The investigated metals were: Zn, Cr, Cu, Fe, Cd, Ni and Pb. The translocation of such metals in the plant roots, stems and leaves was also determined. The level of metals in the influent and effluent of the wastewater, as well as the sludge, was investigated. The concentration factor of each metal by plants and sludge was further studied. Results revealed that P. australis has a higher tendency for the accumulation of metals than S. Lacustris. The level of metals was higher in roots, followed by leaves, then stems. Metals were more concentrated in the sludge than in the plants. Further study showed that the levels of metals in plants grown in the artificial wetlands were higher than in those grown in a “controlled” area. Concludes that vascular plants can act as scavengers of metals from the municipal wastewater while still maintaining a healthy status.

Preparation of chelating resin to be used in the removal of heavy metal ions from solutions.

Chelating resin based on poly (glycidyl‐methacrylate‐co‐N, N‐methylene‐bis‐acrylamide) containing ethylenediamine was synthesised and used in removal of heavy metals from solutions.

The optimal pH values for adsorption of different metal ions occur in the range 4.0‐10.0 depending on the metal ion used. The adsorption of metal ions increases with increasing treatment duration to reach to the equilibrium state. Also, the adsorption of metal ions depends on the degree of cross linking of the chelating resin, and a higher degree of cross linking results in a lower degree of metal ion adsorption. The chelating resin was highly effective for the collection of metal ions by batch and column methods. The metal ions adsorbed could be eluted with 2M HNO₃ except Co²⁺ and the resin could be reused.

The different factors affecting the metal ions (Cu²⁺, Co²⁺, Cd²⁺, Zn²⁺, Pb²⁺ and Hg²⁺) loading in resin such as pH, contact time and cross linking density were studied.

The practical applicability of the chelating resin for final stage of waste water treatment is recommended for use as a polishing agent.

The resins prepared were used successfully in removing heavy metals from water.

Introduction Clad metals are composites of two or more metals which are joined in a continuous manner by a metallurgical bond. The composite provides the specific advantages of both metals, usually the good corrosion resistance of the cladding metal and the strength and economy of the backing metal.

This paper aims to report an experimental investigation of the galvanic corrosion that occurs between the base metal and the welds in X52 carbon steel petroleum pipelines when exposed in carbon dioxide (CO₂)-containing saltwater at pH 4 at room temperature. The pipeline was fabricated by electric resistance welding (ERW).

The experimental setup was a closed glass cell equipped with a silver/silver chloride (Ag/AgCl) reference electrode, two working electrodes (the weld metal and the parent steel specimens) and a gas bubbler. The corrosion potential and polarization resistance of the base metal and the weld were determined using electrochemical testing methods: potentiodynamic polarization scans and linear polarization resistance measurement. The galvanic currents of the base metal when coupled to the weld metal were measured using zero resistance ammetry.

The weld metal was the anode of the couple for a very short time at the beginning of the experiment and then became the cathode until the end of the experiment. This indicates that electric resistance welded X52 steel pipe is a promising material to be operated in CO₂-containing saltwater at pH 4 and 25°C because the weld area is cathodic to the parent metal, the value of the galvanic current is very low (in the order of nanoamps) and the area of the anode (i.e. the parent metal) is significantly larger than that of the cathode (weld metal).

Further experimental research could be performed to investigate the galvanic corrosion behavior between the parent metal and the weld area of X52 carbon steel petroleum pipelines in CO₂-containing saltwater at different pH values, temperature and velocity.

Electric resistance welded X52 steel pipe is a promising material for use with CO₂-containing saltwater environments at pH 4 and 25°C.

The new information presented in the paper is the galvanic corrosion behavior between the parent metal and the ERW weld metal of X52 carbon steel in CO₂-containing solutions. The paper should be useful to researchers working in the field of oil industry corrosion.

Every metal has a range of environmental conditions against which it is resistant or sufficiently resistant as to make the metal economically feasible. Unfortunately it is almost a rule of thumb that the more expensive the metal the smaller the range. In most cases the resistance of the metal is a function of the metal thickness, but the function is such that relatively thin metals can produce very long lives.

An experimental investigation for developing structure-property correlations of hot-rolled E410 steels with different carbon contents, i.e. 0.04wt.%C and 0.17wt.%C metal active gas (MAG) and cold metal transfer (CMT)-MAG weldments was undertaken.

Mechanical properties and microstructure of MAG and CMT-MAG weldments of two E410 steels with varying content of carbon were compared using standardized mechanical testing procedures, and conventional microscopy.

0.04wt.%C steel had strained ferritic and cementite sub-structures in blocky shape and large dislocation density, while 0.17wt.%C steel consisted of pearlite and polygonal ductile ferrite. This effected yield strength (YS), and microhardness being larger in 0.04wt.%C steel, %elongation being larger in 0.17wt.%C steel. Weldments of both E410 steels obtained with CMT-MAG performed better than MAG in terms of YS, ultimate tensile strength (UTS), %elongation, and toughness. It was due to low heat input of CMT-MAG that resulted in refinement of weld metal, and subzones of heat affected zone (HAZ).

A substantial improvement in YS (∼9%), %elongation (∼38%), and room temperature impact toughness (∼29%) of 0.04wt.%C E410 steel is achieved with CMT-MAG over MAG welding. Almost ∼10, ∼12.5, and ∼16% increment in YS, %elongation, and toughness of 0.17wt.%C E410 steel is observed with CMT-MAG. Relatively low heat input of CMT-MAG leads to development of fine Widmanstätten and acicular ferrite in weld metal and microstructural refinement in HAZ subzones with nearly similar characteristics of base metal.

Gallic acid is a substance that is widely found in nature. Initially, it was only used as a corrosion inhibitor to retard the rate of corrosion of metals. In recent years, with intensive research by scholars, the modification of coatings containing gallic acid has become a hot topic in the field of metal protection. This study aims to summarize the various preparation methods of gallic acid and its research progress in corrosion inhibitors and coatings, as well as related studies using quantum chemical methods to assess the predicted corrosion inhibition effects and to systematically describe the prospects and current status of gallic acid applications in the field of metal corrosion inhibition and protection.

First, the various methods of preparation of gallic acid in industry are understood. Second, the corrosion inhibition principles and research progress of gallic acid as a metal corrosion inhibitor are presented. Then, the corrosion inhibition principles and research progress of gallic acid involved in the synthesis and modification of various rust conversion coatings, nano-coatings and organic resin coatings are described. After that, studies related to the evaluation and prediction of gallic acid corrosion inhibition on metals by quantum chemical methods are presented. Finally, new research ideas on gallic acid in the field of corrosion inhibition and protection of metals are summarized.

Gallic acid can be used as a corrosion inhibitor or coating in metal protection.

There is a lack of research on the synergistic improvement of gallic acid and other substances.

The specific application of gallic acid in the field of metal protection was summarized, and the future research focus was put forward.

To the best of the authors’ knowledge, this paper systematically expounds on the research progress of gallic acid in the field of metal protection for the first time and provides new ideas and directions for future research.

This study aims to present the numerical analysis of exergy transfer and irreversibility through the discrete filling of high-porosity aluminum metal foams inside the horizontal pipe.

In this study, the heater is embedded on the pipe’s circumference and is assigned with known heat input. To enhance the heat transfer, metal foam of 10 pores per inch with porosity 0.95 is filled into the pipe. In filling, two kinds of arrangements are made, in the first arrangement, the metal foam is filled adjacent to the inner wall of the pipe [Model (1)–(3)], and in the second arrangement, the foam is located at the center of the pipe [Models (4)–(6)]. So, six different models are examined in this research for a fluid velocity ranging from 0.7 to7 m/s under turbulent flow conditions. Darcy Extended Forchheimer is combined with local thermal non-equilibrium models for forecasting the flow and heat transfer features via metal foams.

The numerical methodology implemented in this study is confirmed by comparing the outcomes with the experimental outcomes accessible in the literature and found a fairly good agreement between them. The application of the second law of thermodynamics via metal foams is the novelty of current investigation. The evaluation of thermodynamic performance includes the parameters such as mean exergy-based Nusselt number (Nu_e), rate of irreversibility, irreversibility distribution ratio (I_DR), merit function (MF) and non-dimensional exergy destruction (I^*). In all the phases, Models (1)–(3) exhibit better performance than Models (4)–(6).

The present study helps to enhance the heat transfer performance with the introduction of metal foams and reveals the importance of available energy (exergy) in the system which helps in arriving at optimum design criteria for the thermal system.

The uniqueness of this study is to analyze the impact of discrete metal foam filling on exergy and irreversibility in a pipe under turbulent flow conditions.