Study on the role of the accident statistics in the design of coal mine safety signs

Accident statistics is an important basis in designing coal mine safety signs. In this paper, we study the process and feasibility for accident statistics as the design basis of the coal mine enterprise safety signs. This paper comes into a conclusion of unsafe actions which cause the accident can be divided into two categories: illegal action and error action. Illegal action could be subdivided into habitual illegal action and accident illegal action, while error action could be subdivided action into skills, decisionmaking and physiological perceptual action. In this paper, we specifically analyze five coal mine accident cases as examples, in order to conclude unsafe actions and unsafe states in every case. Specifically, unsafe acts are: bolt pretightening does not reach the designated position, sitting on the belt, no remote operating point column, maintenance without power cuts and operating under pressure. In addition, these unsafe acts lead to relative unsafe states, which are insufficient bolt pressure, point column instability, machine charging electricity and hydraulic pipe under pressure? Finally, these unsafe states become causations of accidents. Based on statistical analysis, we found out illegal actions of coal mine accident cases and specifically designed five safety signs, which are ‘bolt must be preloaded in place’, ‘be careful of the column’, ‘ban to sit on belts’, ‘forbidden pressing operation’ and ‘maintenance must be power outages’.

Determining temperatures and forces necessary to produce hot-pressed tubes out of titanium alloy PT-1M

This paper describes the results of a study that looked at alloy PT-1M that refers to the Ti – Al system and the α-alloys of titanium and is used to make tubes for various applications, including tubes that are hot-pressed as part of the manufacturing process. When developing a procedure for making hot-pressed tubes, one should first determine the temperatures and forces of the pressing operation that would ensure production of quality semifinished tubes. By means of test quenching operations, optical microscopy, thermodynamic analysis performed in ThermoCalc and physical modelling of the hot deformation process carried out in Gleeble 3800, as well as a series of mathematical calculations, the authors were able to determine the polymorphic α + β → β transformation temperature, as well as temperature regions of heating and forces that are necessary for hot pressing of the titanium alloy PT-1M for producing tubes of a given size at the TMK Group facilities. Having analyzed the temperature region of the α + β → β transformation in alloy PT-1M through thermodynamic calculation in ThermoCalc, the authors came up with recommended test temperatures for the PT-1M alloy for estimating the hot deformation forces required. The authors simulated the process of hot deformation by compressing specimens of the PT-1M alloy in the recommended temperature range, explained how the forces changed as a function of temperature and true deformation rate and determined the maximum forces and the strain-induced heating. The calculations show that, in the temperature range recommended for pressing tubes of a given size from PT-1M workpieces, the peak loads do not exceed the capacity of the pipe press in view. This research was funded by the Russian Science Foundation (Project No. 18-79-10107).

Implementation of Lean in Four-Wheel Drive Front Axle Sub Assy line

This project deals with the Optimizing the process and eliminating the waste in Four Wheel Drive front axle sub assembly line. Four wheel drive sub assembly line consist of 20 different sub-assemblies are available. In which Axle housing sub assy takes more time to complete i.e. around 20.8 min which is more than TAKT time. In this most fatigue operation is Bush pressing which is done by manual hammering. Due to the manual hammering process TAKT time increases and improper bush assy into the axle housing which leads to failure in the front axle function which results in warranty claims thus increasing the external cost to the company. As the existing process is manual, the accuracy of the pressing operation is not to the standards, while pressing the bush, there is no assurance of full placement of the bush in the axle, also the fatigue is more, and there may be chances of lack of skill in the work. The interference tonnage is found to be 3 to 4 tonnes and so the intensifier unit for the appropriate pressure is to be designed initially 100% inspection is done after bush pressing to check correct position of bush assy, internal diameter of the bush using gauges, Further through PFMEA critical process are identified for failure .

Cutting procedure modification in hob cutters for multiple-thread spiral projection shaping on mandrel

An efficient technology for helical groove shaping on inner cylindrical surfaces with the use of a pressing operation through a ring matrix on a spiral press mandrel is described. There are presented investigations and offers are given to update spiral projection gear milling in mandrels with the aid of milling cutters with a modified cutting procedure.

Магнитные свойства прессованных нанопорошков гексаферрита бария

Magnetic force microscopy and magnetometry were used to study the magnetic characteristics of pressed nanosized powders BaFe12O19. The powders were obtained by chemical coprecipitation. Magnetic anisotropy of the “easy-plane” type, formed after the pressing operation, was found. The nature of the appearance of anisotropy is discussed.

Using of ltcc-technology to obtain hexagonal ferrites for substrates microstrip devices microwave electronics mm-range of wavelengths

In the work by the method low temperature co-fired ceramics (LTCC) obtained samples of isotropic and anisotropic polycrystalline hexaferrite BaFe12O19 and SrFe12O19. Using in the LTCC-technology the pressing operation for samples (tablets) in a magnetic field produces anisotropic hexaferrites, pressing without a magnetic field - isotropic hexaferrites. Application in the LTCC-technology molding process tape produces exclusively isotropic samples.

Phase Transformations of the Ti-40% Nb Alloy Under External Influence

The phase transformations of the alloy Ti-40 mas % Nb after tempering and severe plastic deformation are studied. The phase transformations of the alloy according to the type and conditions of external influences are analyzed using methods of XRD, SEM and optical metallography. It is determined that inverse phase transformation of the metastable α''-phase to equilibrium β-phase is carried out after severe plastic deformation. Complete phase transformation α'' → β is typical for the mode, which consists of three pressing operation with the change of the loading axis in cramped conditions, followed by a multi-pass rolling in grooved rolls.

Mechanical Properties Of Composite Biomass Briquettes

In the handling and usage processes, sufficient density and durability of biomass (straw, read) briquettes should be provided. For the briquettes density standards determined the value ρ > 1.0 g cm-3. In ? the densification process usually fine grinded particles are used, what significantly increases energy consumption for stalk material cutting. Calculated energy consumption for common reed cutting to sizes less than 3 mm was > 7 kJ kg-1 but for size 20 mm it was approximately 1 kJ kg-1. The goal of the investigation was to obtain the necessary density and durability of briquettes of larger biomass particles by arranging them. The orientation of straw or reed stalks had to promote binding by the pressing operation. The long stalk linking, in the picture of coloured stalk briquettes sections, is good visible. Crushing force dependence on particle size for arranged structure briquettes is stated in laboratory experiments. The specific splitting force of arranged structure coarse chopped wheat straw and reed briquettes reaches value 35 N mm-1. It is approximately the same as industrially produced wood briquettes. Splitting force of the hemp stalk briquettes reaches 115 N·mm-1.

The role and the influence of fine pulp in sugar beet processing

Recycling of fine pulp, i.e. small pulp fragments, formed during pressing of exhausted cossettes impairs the correct operation and the performance of the pulp press station. In general, the recycling negatively influences the economics of a sugar factory causing increasingly higher costs in the course of the campaign, for example, due to lower perfomance of the pulp presses and extractors or by increasing the infection level In order to optimise the pulp pressing operation it is recommended first to separate fine pulp from the press water and then to press fine pulp by means of dedicated presses, thus increasing the overall value of pressed pulp.

Production of Ultra-Fine-Grained Aluminum Plates by Constrained Groove Pressing Technique

One of the new methods of producing materials that have ultra-fine grains or grains of nanometer size is the method of severe plastic deformation (SPD). In this technique, by applying severe strains to the samples, the size of the grains is reduced to the nano scale, and as a result, the mechanical properties of the metal (including the yield strength and resistance to wear and abrasion) improve considerably. In this research, the effect of the constrained groove pressing process (as one of the SPD methods) on aluminum plates was studied. In this method, two dies (one with asymmetrical grooves, and the other, flat) were used for pressing the aluminum samples. With respect to the die’s geometry, at each pressing run, a shear strain equal to 0.58 is applied to some parts of the sample. By repeating the pressing operation, a large and significant amount of plastic strain is applied throughout the sample. In the present investigation, tensile and microhardness tests were employed to determine the effect of this process on the mechanical properties of the samples,. The results showed that, by increasing the number of pressing steps, hardness and strength of the samples increase, and the elongation ability diminishes. Of course, at higher numbers of pressing steps, a little decrease in strength was observed in the samples. Complete explanations regarding this decrease have been given in the text of the article.