Study on X-ray Induced Two-Dimensional Thermal Shock Waves in Carbon/Phenolic

Carbon/Phenolic (C/P), a typical anisotropic material, is an important component of aerospace and often used to protect the thermodynamic effects of strong X-ray radiation. In this paper, we establish the anisotropic elastic-plastic constitutive model, which is embedded in the in-house code “RAMA” to simulate a two-dimensional thermal shock wave induced by X-ray. Then, we compare the numerical simulation results with the thermal shock wave stress generated by the same strong current electron beam via experiment to verify the correctness of the numerical simulation. Subsequently, we discuss and analyze the rules of thermal shock wave propagation in C/P material by further numerical simulation. The results reveal that the thermal shock wave represents different shapes and mechanisms by the radiation of 1 keV and 3 keV X-rays. The vaporization recoil phenomenon appears as a compression wave under 1 keV X-ray irradiation, and X-ray penetration is caused by thermal deformation under 3 keV X-ray irradiation. The thermal shock wave propagation exhibits two-dimensional characteristics, the energy deposition of 1 keV and 3 keV both decays exponentially, the energy deposition of 1 keV-peak soft X-ray is high, and the deposition depth is shallow, while the energy deposition of 3 keV-peak hard X-ray is low, and the deposition depth is deep. RAMA can successfully realize two-dimensional orthotropic elastoplastic constitutive relation, the corresponding program was designed and checked, and the calculation results for inspection are consistent with the theory. This study has great significance in the evaluation of anisotropic material protection under the radiation of intense X-rays.

Possibilities of Capturing Methane from Hard Coal Deposits Lying at Great Depths

Methane present in coal seams is a natural hazard present during the exploitation of underground mining plants. It is an explosive and flammable gas that is released into mining excavations, and it is necessary to reduce its concentration. Capturing methane while preparing extraction is virtually impossible due to the low permeability of coal resulting from its deposition depth. After the beginning of exploitation and disrupting the seam’s structure, methane is released into mine air. The most common method of minimizing gas released into ventilation air is draining the rock mass. This method allows achieving the desired ventilation parameters but requires appropriate mining techniques in hazardous areas. The article presents the example of methane capture during the operation in the longwall B-15 with an overlying drainage gallery. The authors have highlighted an example of the longwall B-15 that when using this particular drainage method, allowed capturing twice the amount of methane forecasted, thus increasing the efficiency of methane drainage. At the preliminary stage of longwall development, the amount of methane charged by the drainage system had relatively low values, reaching 15 m3/min. In the next few months, these parameters increased and varied between 35 to 55 m3/min. A significant difference in methane capture appeared in the second stage of exploitation, where the highest value of captured methane reached 82 m3/min. This particular longwall example shows that it is crucial to properly design the drainage system for seams with high forecasted methane release. It is worth remembering that using a drainage gallery provides an increase in the methane capture from the desorption zone areas, thus increasing total methane capture in comparison to forecasts.

Simulation of Magnetic-Field-Induced Ion Motion in Vacuum Arc Deposition for Inner Surfaces of Tubular Workpiece

A simulation of magnetic-field-induced ion motion in vacuum arc deposition for the inner surfaces of a tubular workpiece was performed. An auxiliary magnetic field was set to guide the motion of ions inside a pipe, with different magnetic flux densities and ion emission parameters. The results showed the trajectories, deposition ratio and depth of the ions can be controlled via a magnetic field. Within a certain range, the deposition ratio of the ions increases with magnetic flux density. When the magnetic flux density reached a certain value, both the trajectories and deposition ratio of the ions exhibited an obvious periodicity. The depth at which the ions were deposited decreased as an exponential function of the magnetic flux density and ion emission radius, respectively. With an increase in the emission angle, the deposition depth decreased linearly. A numerical model was proposed to express the distribution of the deposition depth. In addition, the deposition ratio and depth are improved with a magnetic field in an environment with a certain density of neutral gas.

Growth of ZnS:Ag:Cu Thin Film Deposited on Glass Substrates using Thermal Evaporation Technique for Alpha-photovoltaic

This paper presents the research on the growth of ZnS:Ag:Cu thin film on a glass substrate as a radio-luminescent material. The SRIM/TRIM software is used to determine the optimum thickness based on an energy deposition depth of 5.485 MeV Am 241 alpha radiation source on ZnS:Ag:Cu material. To increase the adhesive strength of the coating, initially, the glass substrate is etched using a plasma glow discharged at 280°C for 15 minutes. Multiple coatings of ZnS:Ag:Cu were etched on the glass substrate; this was carried out using a thermal evaporation technique to achieve the optimal thickness (based on SRIM/TRIM simulation). The thin film thickness was observed using a scanning electron microscope (SEM). The optical properties of the un-etched, etched glass substrate and thin-film were characterized using UV-Vis spectrometer. Based on SRIM/TRIM simulation, the optimal thickness is 22 mm which can be achieved by coating three times. From optical properties of ZnS:Ag:Cu thin film and after being analysed using Taue plot method, it is found that the energy gap of ZnS:Ag:Cu thin film is 2.48 eV. It can be concluded that the addition of Ag and Cu doped decrease the energy gap of ZnS (3.66 eV).

Profile composition of defined energy by products at landfill

A number of new findings can be derived from the data obtained. After the initial drop, the water content stabilized at about 30% wt. This finding is likely to correspond to the groundwater level. An unexpected decrease in its content of about 3 to 5 m to about half of the depths from 12 m can be considered unexpected. The CaO concentration decreases from about 42 wt. % to about 25 wt. % in the first seven meters. At 10 meters, it then rises to around 30% by weight. Leaving aside the possibility that this change could be related to the CaO concentration already in the deposited material, this finding can be attributed to the transport of calcium compounds with leaking water. Similar changes in concentration with deposition depth have been demonstrated for sulphates. However, this unexpected calcium data will be related not only to the dissolution of calcium sulfate but also to the dissolution of other calcium salts. The related Mg compounds will not significantly contribute to this process, since the MgO concentration practically does not change with deposition depth. The same applies to BaO. In this context, long-term “washing” of carbonates from landfill into groundwater can also be expected. This has not been monitored yet, because it is a non-toxic, not monitored substance. It is clear from the model study that by-products from the operation of brown coal-fired fluidized bed boilers and using limestone as a desulfurization medium during storage in a landfill chemisorb a significant amount of carbon dioxide from the ambient air. This reactivity should be taken into account in the carbon dioxide balance of energy sources, which is not yet respected.

Treatment of seborrheic keratosis with a copper vapour laser

Aim: to assess the efficacy and side-effect risk of the surgical treatment of seborrheic k eratosis (SK) using a copper vapour laser (CVL).Patients and methods. 3980 patients (1214 men and 2766 women aged 20 to 78 years) suffering from SK were treated using a CVL (Yakhroma-Med model, Russian producer) equipped with a laser pen and a scanning nozzle. The laser treatment was performed without anaesthesia in one to four sessions. During the treatment procedure, the following radiation parameters were applied: wavelengths ranging from 511 to 578 nm (in the ratio of 3 to 2), an average power of 0.6–1.2 W and an exposure duration ranging from 0.2 to 0.4 s. The diameter of the light spot on the skin surface was 1 mm. The follow-up observation lasted 24 months.Results. The computer simulation of tissue heating by CVL and other laser systems showed that CVL is an optimal treatment choice for seborrheic keratosis in terms of the energy deposition depth. According to our clinical data and the results of computer simulation, the CVL is established to be the safest and the most effective for seborrheic keratosis treatment.

Effect of the Sowing Speed on the Distribution Regularity of Maize Seeds

This work aimed to evaluate the influence of the sowing speed on the regularity of longitudinal distribution of maize seeds through a pneumatic metering seeder. The experimentation of 4 sowing speeds (4, 6, 8 and 10 km h-1) was performed in randomized blocks design with four replicates. The parameters evaluated were the mean distance between plants, coefficient of variation of the distance between plants, percentage of acceptable, flawed and double spacings, precision index, plant stand, initial population, mean seed deposition depth, and coefficient of variation of the seed deposition depth. The increase in the operating speed linearly reduced the percentage of acceptable spacings, plant stand, initial population, and mean seed deposition depth. Conversely, it linearly increased the values of mean distance between plants, coefficient of variation of the distance between plants, percentage of double and flawed spacings, precision index, and coefficient of variation of the deposition depth. Therefore, the increase in the displacement speed of the tractor-seeder set reduced the regularity of the longitudinal distribution of the plants, as well as the sowing quality.

Optimization of the Alpha Energy Deposited in Radioluminescence Thin Film for Alphaphotovoltaic Application

Activated zinc sulfide (ZnS) is a semiconductor material which able to emit photon in the form of visible light when expose to external energy. The capability of activated ZnS, mainly doped with silver (Ag) and copper (Cu), to convert radiation become light to make it potentially applicable as the radioluminescent thin film for alphaphotovoltaic-type nuclear battery. One of the important specifications of the radioluminescence layer that influences the fluorescence efficiency is the thickness. This work presents a study on the thickness optimization for ZnS:Ag:Cu as the radioluminescent film for alpha particles using Monte Carlo model. Simulation to study alpha particles’ energy deposited by using Stopping and Range of Ions in Matter/TRansport of Ions in Matter (SRIM/TRIM) code. The model examined the transport of 5.485 MeV alpha particles emitted by to determine the best thickness based on energy deposition depth. Based on TRIM module simulation, the optimal thickness for radioluminescence film is approximately 19-22 µm. Most energy from 5.485 MeV alpha particles is deposited in 18.92 µm depth activated zinc sulfide. The results from SRIM/TRIM model then compare with analytical calculation using Bragg-Kleman rule. The alpha particles stop at 22 µm from the SRIM/TRIM simulation while using Bragg-Kleman formula the alpha particles stop at 23.51 µm.

Variability of Mercury Content in Coal Matter From Coal Seams of The Upper Silesia Coal Basin

The process of identifying and documenting the quality parameters of coal, as well as the conditions of coal deposition in the seam, is multi-stage and extremely expensive. The taking and analyzing of seam samples is the method of assessment of the quality and quantity parameters of coals in deep mines. Depending on the method of sampling, it offers quite precise assessment of the quality parameters of potential commercial coals. The main kind of seam samples under consideration are so-called “documentary seam samples”, which exclude dirt bands and other seam contaminants. Mercury content in coal matter from the currently accessible and exploited coal seams of the Upper Silesian Coal Basin (USCB) was assessed. It was noted that the mercury content in coal seams decreases with the age of the seam and, to a lesser extent, seam deposition depth. Maps of the variation of mercury content in selected lithostratigraphic units (layers) of the Upper Silesian Coal Basin have been created.

Chronology of multicultural site Sowinki in Greater Poland

Sowinki is a village located 35 km south of Poznań, where archaeological research has revealed the remains of settlement from different archaeological periods, ranging from the Mesolithic (ca. six thousand years BC) to the Late Medieval period (ca. 15th century AD). This area, therefore, provides a record of the history of Greater Poland (Poznań) region, tracing back to about seven and a half thousand years ago. Samples of bones and wood were collected from different features, including mostly cellar pits, refuse pits and grave pits. Eight of the samples, all collected from grave pits, were selected for radiocarbon dating. The obtained 14C measurements have confirmed previous findings concerning different cultures registered in the studied area, and additionally, they have helped to clarify chronology of the early medieval cemetery. The presented results are the first isotopic measurements taken for the site of Sowinki. Previously, chronological frameworks of this site were determined on the basis of relative chronology, according to stratigraphy of sediments, examination of metal finds, pottery and flint objects. The deposition depth of the analysed charcoals did not exceed 100 cm below ground level. According to the analysis, all the samples date to the time of the early Piasts’ dynasty. The obtained data have allowed for defining two chronological phases of the early medieval cemetery. This is an important archaeological site both in terms of its spread and the long time of existence. In addition, it provides a valuable background for the study on the emergence of early medieval elites and the formation of the Polish “early feudal” state.