Safety in Handling of Metal Powders

To investigate the explosive characteristics of solid–liquid mixed fuels containing different types of metal powders—including hydrogen-storage metal powders—and volatile liquid fuels, explosion experiments and corresponding numerical simulations were conducted under unconstrained space conditions. The studied system consisted of Et2O/Al/B/MgH2 mixed fuels with varying composition ratios. Research has shown that the dispersion effect of solid–liquid mixed fuel containing metal dust under strong shock waves is higher than that of pure liquid fuel. And the explosion overpressure and temperature of solid–liquid mixed fuel are higher than that of pure liquid fuel. Under the same solid–liquid ratio, the explosive overpressure of Et2O/Al/B/MgH2 mixed fuel was the highest, which was 110.8% higher than that of pure liquid fuel at the 5 m position. For solid–liquid mixed fuels containing different metal powders, due to the high reaction threshold of boron powder, a high-activity MgH2 reaction is required to drive the reaction. Therefore, the explosive strength of the mixed fuel systems follows the order Et2O/Al/B/MgH2 > Et2O/Al/MgH2 > Et2O/Al > Et2O/Al/B. Meanwhile, simulation models for pure liquid and solid–liquid fuel explosions were established. The discrepancy between the simulated results and the experimental data was within 10%, demonstrating that the proposed model provides an effective and reliable approach for predicting the explosive power and hazardous range of fuel–air explosions.

In this study, high-purity tantalum metal powder was manufactured via self-propagating high-temperature synthesis. During the process, Ta2O5 and Mg were used as the raw material powder and the reducing agent, respectively, and given that combustion rate and reaction temperature are important factors that influence the success of this process, these factors were controlled by adding an excessive mass of the reducing agent (Mg) i.e., above the chemical equivalent, rather than by using a separate diluent. It was confirmed that Ta metal powder manufactured after the process was ultimately manufactured 99.98% high purity Ta metal powder with 0.5 µm particle size. Thus, it was observed that adding the reducing reagent in excess favored the manufacture of high-purity Ta powder that can be applied in capacitors.

Aspects of Powder Technology in Ancient and Medieval India

Comparison of calcium–magnesium-alumina-silicate (CMAS) resistance behavior of produced with electron beam physical vapor deposition (EB-PVD) method YSZ and Gd2Zr2O7/YSZ thermal barrier coatings systems

96/00941 Environmental management in an internatinal consumer goods company

One of the most dangerous and dehumanizing activity in many developing countries is waste scavenging, an act of selecting possible useful or materials from waste materials especially at waste dump sites for purposes of making a living. This act exposes waste scavengers to several occupational health risks and hazards ranging from cuts, needle stick injury, and exposure to particulate matter, disease causing organisms, contaminated food and water, unhygienic working environment, among other health hazards. In Nigeria, population growth has resulted in an uncontrolled increase in waste creation, making it impossible for waste management organizations in various states to cope. Thus, increasing the number of waste scavengers who use waste picking as a daily source of income and a routine vocation to reduce the unemployment gap. This study was therefore performed to assess health and safety risk among waste scavengers in Enugu state, Nigeria with a view to identifying health conditions associated with waste scavengers in the state. This research adopted a descriptive cross-sectional approach in sampling 396 wastes scavengers across the three senatorial districts of Enugu state. A multistage and random sampling technique with instruments of questionnaires as well as risk assessments of the dumpsites were used to achieve the research objectives. Findings revealed that most of the respondents were exposed to all types of hazards with (79.8%) prevalence of physical hazard, (52.3%) prevalence of biological hazard, (61.6%) prevalence of chemical hazard, (60.6%) prevalence of psychological hazard and (95.7%) prevalence of ergonomic hazard. Due to exposures to broken glasses, needles, nails, metals, bottles, trips and falls, dust, machinery, computer equipment, woods, faeces, used condoms, food wastes, decaying materials, insects, rats, snakes, battery, poisoning from insecticides, decaying materials, chemical substances, lifting heavy bags of picked solid waste materials such as metals and plastics. Study recommends the use of PPEs by scavengers and enforcement of the use by government to ensure their exposures to some of these hazards are reduced. Also, recommends collaboration of Government with health workers to organize frequent health education and promotion to educate the waste scavengers on various types of health hazards.

The establishment and growth of the small businesses in South Africa is of vital importance for economic stability and progress in the economy. A key small business management skill comprises occupational health and safety management, with particular reference to the proper identification of safety hazards and safety risks. This conceptual article set out to identify current perceptions about the concepts of safety, safety risks and safety hazards in the workplace while also identifying and analysing misconceptions regarding safety hazards. This article reports on a secondary data analysis of relevant literature on safety hazards and safety risk and the role thereof on small business success. The structure and functioning of the interrelated characteristics of safety hazards were visualised, with the objective of allowing small business owners or managers to understand how safety hazards contribute to safety risks. Proper identification of safety hazards and safety risks, along with adequate protection measures, allows for improved productivity and a reduction in operational costs. Safety hazards in the workplace, encompassing the functional and structural characteristics, such as humans and machinery, should be noted by small business owners, as applicable to all types of businesses. This article may serve as a catalyst for small business success through growth and sustainability by implementing enhanced safety management practices based on an accurate identification and analysis of safety hazards and safety risks. It allows for the identification and proactive mitigation of safety hazards and safety risks in all types of small businesses.

Construction safety and health management has improved significantly following the Occupational Safety and Health Act of 1970. In response to this legislation, contractors began implementing safety programs to reduce occupational safety and health hazards on construction sites. Researchers recently found that the current process of selecting specific elements for a safety program is informal. This paper describes the results of a recent study designed to determine the relative effectiveness of safety program elements by quantifying their individual ability to mitigate construction safety and health risks. In order to determine the effectiveness of individual safety program elements, the following research activities were performed: (1) an appropriate safety risk classification system was created using an aggregation of relevant literature; (2) highly effective safety program elements were identified in literature; and (3) the ability of each safety program element to mitigate a portion of each of the safety risk classes was quantified using the Delphi method. The results of the research indicate that the most effective safety program elements are upper management support and commitment and strategic subcontractor selection and management and the least effective elements are recordkeeping and accident analyses and emergency response planning. It is expected that the data presented in this paper can be used to strategically select elements for a safety program, target specific safety and health risks, and influence resource allocation when funds are limited.

The technology of producing metal powder from molten silver containing 99,9 % Ag, by dispersing the melt by gas atomization using water. The results of the study of experimental batches showing the relationship shapes and sizes of the powder particles at different angles partition melt jet stream of high pressure water

Introduction to Metal Powder Production and Characterization

With the booming of additive manufacturing, metal powder manufacturers are facing a growing demand of gas atomized powder complying with very stringent technical specifications in terms of oxidation or particle size distribution (PSD).From a metal powder producer perspective, optimizing the PSD makes possible to be more selective in terms of targeted markets and results in a direct increase of profitability, also limiting waste and thus carbon footprint.Most of the atomization processes deal with a complex interaction between the metal and a gas jet. The literature of metal powder production stands for a narrowing of the particle size distribution with the optimization of the momentum of the gas jet. It could include the change of the flow, pressure and temperature of the inlet gas but also its composition, considering gas mixtures.This work presents results of trials conducted on an industrial gas atomization unit using nitrogen as gas stream to atomize

Metal dusting is a severe form of corrosive degradation of metals at high temperatures in carbon-supersaturated gaseous environments . , , and base high-temperature alloys and steels are all susceptible. The corrosion manifests itself as a breakup of bulk metal to metal powder; hence, the term metal dusting. In the present study, metal dusting corrosion of 304 stainless steel (SS) is simulated in high carbon activity environments over a temperature range from 550 to . 304 SS corrodes by transfer of carbon and its subsequent diffusion and precipitation in the steel interior pursuant to local rupture of a protective surface oxide film. The focus of this research is to advance the understanding of the corrosion mechanisms of this type of steel by characterizing interfacial processes at the nanometer level. In addition to the effect of temperature and the role of surface finish on corrosion, the mechanistic aspects of metal dusting are discussed with particular attention to stages of microstructure evolution as degradation proceeds.

Synthesis of Mg–Zn–Ca metallic glasses by gas-atomization and their excellent capability in degrading azo dyes

This paper mainly studies the coal mine safety risk, including the classification, management strategy of coal mine safety risk and the development of risk management information technology. For the management of coal mine safety risks, it is very effective to formulate a safety risk classification management system, which can find and manage various safety hazards and risks as soon as possible, and promote efficient and safe operation. Nowadays, people increasingly take safety issues seriously in the coal industry, so the development of safety risk classification and control system has become an important safety management tool. To solve the slow convergence rate of CNN algorithm, this paper uses PSO to improve the error back propagation of CNN by using the training parameters and error functions of CNN as PSO particles and fitness functions respectively. The experimental simulation of AR face database in gender identification verifies that the improved algorithm has fast convergence rate and high recognition accuracy.

Gas atomization is one of the methods for production of clean metal powders at relatively moderate cost. A laboratory scale gas atomizer was designed and fabricated indigenously to produce metal powders with a batch capacity of 500g of copper (Cu). The design includes several features regarding fabrication and operation to provide optimum conditions for atomization. The inner diameter of atomizing chamber is 440 mm and its height is 1200 mm. The atomizing nozzle is of annular confined convergent type with an angle of 25o . Argon gas at desired pressure has been used for atomizing the metals to produce relatively clean powders. A provision has also been made to view the atomization process. The indigenous laboratory scale gas atomizer was used to produce tin (Sn) and copper (Cu) powders with different atomizing gas pressures ranging from 2 to 10 bar. The particle size of different powders produced ranges from 40 to 400 µm.