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In this experimental study, picosecond laser treatment was performed on a nickel-based superalloy Nimonic 263, aiming to investigate the surface effects induced by irradiation in different atmospheric conditions and, concerning changes in surface composition, regarding the possibility for improvement of its functionality. Besides the varying laser parameters, such as a number of pulses and pulse energy, environmental conditions are also varied. All surface modifications were carried out in standard laboratory conditions and a nitrogen- and argon-rich atmosphere. The resulting topography effects depend on the specific laser treatment and could be categorized as increased roughness, crater formation, and formation of the laser-induced periodic surface structures (LIPSS). Changes in the chemical surface composition are distinguished as the potential formation of the protective oxides/nitrides on the sample surface. Numerous characterization techniques analyse the resulting effects on the topography and surface parameters. The multi-response parametric optimization of the picosecond laser process was performed using an advanced statistical method based on Taguchi’s robust parameter design. Finally, the optimal parameter conditions for Nimonic 263 modification are suggested.

The paper presents parametric optimization of two heterogeneous laser-based processes with multiple outputs (laser drilling and laser shock peening), using an advanced optimisation methodology. The data obtained from experimentations are processed by statistical method to address requirements for multiple responses, and then the process interrelationships are mapped using artificial neural networks. The neural process model is fed into three major metaheuristic algorithms whose effectiveness are benchmarked: genetic algorithm, simulated annealing and particle swarm optimization. The results are discussed in terms of the quality of the obtained solutions and convergence rate, as well as the influence of the algorithm's hyper-parameters on the obtained results. The adopted optimization results are successfully verified in practice. The recommendations for the metaheuristic algorithm selection and guidelines for the algorithm settings are drawn.

Gas rectification columns are process apparatuses which are very important part of each onshore plant. Sudden failure of these types of columns causes huge daily losses, while fluid leakage can be very dangerous for the people and hazardous for the environment. For that reason, a regular and correct examination of the column is of great importance for the continual process of leading. Together with the detailed examination of the column, a risk-based inspection was applied to maximize savings, both material, time, and costs. The expected remaining service life of rectification columns was also analyzed, while the corrosion rates were calculated according to the various international standards. The minimum required column wall thickness was calculated according to the most commonly used international standard and the obtained difference was analyzed. Detailed analysis of the total risks of the column due to potential failure is presented.

Abstract The surface of a titanium-based alloy Ti6Al4V was subjected to modifications by a near-IR femtosecond Ti:Sapphire laser, emitting at 775 nm pulses of 200 fs duration, in single-pulse and multi-pulse regimes, with up to 400 accumulated pulses, and pulse energies ranging from 2.5 to 250 $$\upmu $$ μ J. The whole range of induced effects is presented, from gentle ablation and pattern occurrence to substantial crater formation. Very observable laser-induced parallel periodic surface structures are reported, appearing both within the damage spot area, with low fluences, and at the peripheries of the craters, with higher fluences—but also on crater walls, and inside the crater structures. Damage threshold fluences $$({F}_{\mathrm{th}})$$ ( F th ) and the incubation factor $$(\zeta )$$ ( ζ ) were also determined. Graphic abstract

Gas heaters used in oil and petrol industry transfer heat to the produced gas stream. Heaters are especially used when producing natural gas or condensate to avoid the formation of ice and gas hydrates. In this work, the inspection practices for process heaters used in petroleum refineries and petrochemical plants is presented as well as critical places for crack formation. After the inspection of the Regeneration Gas Heater the cracks were found and immediately repaired. The inspection is performed using visual, liquid penetrant and ultrasonic testing. The inspection and plan repair by welding is covered according to API 573:2013 and ASME IX:2017. In this work, the results before and after repair are presented and discussed.

The paper presents the characteristics of TiO2 coatings realized by HVOF spraying process by two different processing paths, i.e. using the classical method of preparing the substrate by sandblasting and by applying a fast laser texturing of the substrate (instead of sandblasting) before the actual HVOF spraying respectively (a duplex treatment). The obtained coatings’ morphology were characterized by SEM before and after electrochemical measurements in NaCl solution. The textured sample presented better resistance to corrosion compared with classical processing path. Keywords: coatings, fast laser texturing, HVOF spraying, duplex surface treatment, anticorrosive.

Gas rectification columns are a very important part of each onshore plant. Their sudden failures cause huge losses on a daily basis, while fluid leakage can be very dangerous to people and environment. For that reason, the proper design of the column is of huge importance, among the others safety factors as well. In this paper, the wall thickness measure is presented with the aim to calculate corrosion rate and remaining life of rectification columns. The minimum required column wall thickness was calculated according to the most commonly used international standard and the obtained difference was analyzed.

Nimonic 263 is an alloy with superior mechanical strength and creep resistance at high temperatures and pressure, good formability, and corrosion and oxidation resistance. Due to their high beam density and very short pulses which reduces the heat affected zone (HAZ) Nd:YAG lasers are very suitable for materials drilling. In this paper, the Nimonic 263 sheets, thickness of 2 mm, are laser drilled with various parameters. The influence of laser drilling process on microstructural changes along with the geometrical characteristics are analysed and discussed.

The steels fracture toughness was measured at two different temperature T= - 60°C and T = -90°C, at v=0.02 mm/min and v=0.5mm/min. The following steels: CrMoV, 20MnMoNi55, A533B and A508 were tested with three different sizes of CT specimens 50 and 100 and 200. Those steels are weldable, although the authors investigated the fracture behaviour of base material. In order to satisfy statistical analyses, a large number of specimens were tested. Fracture behaviour has turned out to be typical, S-shaped curve for transitional fracture at low temperatures. Apart from the other variables, specimen’s width significantly affects measured toughness. Smaller specimens, CT50, might be considered of upper bound reliability while the CT200 specimens were shown to be the most conservative. In this way it has been shown that wider specimens are more reliable in a fracture assessment of the examined steels. In this paper, the fracture probabilities of specimens in function of fracture toughness were determined as well, and it could be concluded that the widest specimens are the most likely to be broken for the same values of the fracture toughness.

Laser shot peening (LSP) of material strengthening is nowdays widely used method in various branches of industry. In this paper are presented comparative exeminations of specimen made of NIMONIC and strengthened specimen on which laser shot peening method was performed. Specimens were made as thin plates with holes. Macrostructural surface tests were performed around the specimens holes with different magnifications for both specimens as well as certain damages on the specimens. 3D images of specimens damages provide insights into the its dimensions. In addition, the roughness of non-strengthed and strengthed specimens was also performed. Hardness tests using the Rockwell C method of both specimens show a difference in the hardness of both samples and the main characteristics of the laser shot peening method. Also, the analysis on how the damage of samples could represent the location of initial cracks that could cause failure of the specimens or generally machine part is given as well.

This paper presents an experimental study carried out on Nimonic 263 alloy sheets to determine the optimal combination of laser cutting control factors (assisted gas pressure, beam focus position, laser power, and cutting speed), with respect to multiple characteristics of the cut area. With the aim of designing laser cutting parameters that satisfy the specifications of multiple responses, an advanced multiresponse optimization methodology was used. After the processing of experimental data to develop the process measure using statistical methods, the functional relationship between cutting parameters and the process measure was determined by artificial neural networks (ANNs). Using the trained ANN model, particle swarm optimization (PSO) was employed to find the optimal values of laser cutting parameters. Since the effectiveness of PSO could be affected by its parameter tuning, the settings of PSO algorithm-specific parameters were analyzed in detail. The optimal laser cutting parameters proposed by PSO were implemented in the validation run, showing the superior cut characteristics produced by the optimized parameters and proving the efficacy of the suggested approach in practice. In particular, it is demonstrated that the quality of the Nimonic 263 cut area and the microstructure were significantly improved, as well as the mechanical characteristics.

Preservation of cultural legacy is essential for ensuring its availability for future generations. Long-term indoor storage can sometimes cause the papers to adhere, which can result in the transfer of ink stamps or prints from paper to paper, and subsequently, there emerges the need to remove these types of stains. Laser cleaning emerged as a promising technique for paper surface cleaning. This work presents the laser cleaning of a historical paper dated to the end of the 19th century using the Nd:YAG laser in a nanosecond pulsed regime, at two wavelengths, 532 and 1064 nm, and a semiconductor laser in a continuous regime, at a 552 nm wavelength. The cleaned areas are observed by optical microscopy, scanning electron microscopy, energy-dispersive spectroscopy, and spectrophotometry. The obtained results are discussed in terms of the laser cleaning efficiency characterized by several aspects. The results obtained by green and near-IR laser irradiation in pulsed and continuous regime are compared, showing favorable effects regardless of the laser wavelength. However, in some cases, laser cleaning at 1064 nm wavelength damaged the surface layer of the paper. Cleaning at 532 nm wavelength did not completely remove the ink, and the ink traces were visible under the microscope or spectrometer. The proposed efficient cleaning method for stain, dust, and stamp ink removal from historical papers includes a semiconductor laser at 552 nm, owing to the continuous action of its beam.

Owing to their good mechanical properties, titanium based alloys are used for machine parts and devices that operate in demanding regimes and environmental conditions. Laser shock peening (LSP) is an innovative technique for improvement of the surface and mechanical characteristics of the material. In this paper, LSP is employed for additional improvement of already good characteristics of Ti- alloy. Laser shock peening is performed on alloy surface, with and without protective and transparent layer and obtained microstructure, surface characteristics and mechanical properties are compared. LSP improved the surface topology and microhardness of material, producing overall better results when the Ti-alloy surface was coated by transparent and protective layer.

In this paper, the influence of parameters of laser processing (drilling, cutting, welding and laser shock peening) on microstructure of superalloy Nimonic 263 are investigated. Drilling and welding process are carried out on the Nd: YAG laser model LS-HTS Mobile P160. When drilling the holes, the parameters of pulse frequency (5 Hz, 7 Hz and 9 Hz) and the pulses duration (1.8 ms to 3.6 ms) are varied. The microstructure is investigated and geometrical and metallurgical characteristics of the holes are determined.Cutting is carried out on the laser BISTRONIC, (2000), BISTAR 3015. The parameters that were varied are as follows: the average laser power, laser velocity, the pressure of the assisting gas and the focus position. Based on the geometrical characteristics of the cuts and surface morphology the optimal parameters are discussed and defined. The laser welded joints of Nimonic 263, in addition to microscopic examination and surface profilometry, were subjected to the destructive testing. During the laser shock peening, the samples were exposed to laser light at a wavelength of 1064 nm and 532 nm, with the number of accumulated pulses 50, 100 and 200. The operating laser was Nd: YAG EKSPLO, SL212P model. Structural analysis of Nimonic 263 was carried out using light microscopy, scanning electron microscopy and EDS analysis. Microhardness measurements were carried out using the Vickers method under load of 9,81N. Profilometry was performed on a contactless profilometer Zygo Newview 7100. U ovom radu, proučavan je uticaj parametara određenih procesa laserske tehnike obrade materijala superlegure Nimonic 263 - bušenje, rezanje, zavarivanje i mehanička obrada laserom. Bušenje i zavarivanje su vršeni na laseru Nd:YAG laserom model HTS Mobile LS-P160. Prilikom bušenja rupa varirani su parametri frekvencije impulsa (5 Hz, 7Hz i 9 Hz) i dužine trajanja impulsa (1,8 ms do 3,6 ms). Ispitivana je mikrostruktura i određene su geometrijske i metalurške karakteristike rupa dobijenih ovim parametrima, na osnovu čega je izvršena optimizacija parametara obrade. Rezanje je izvedeno na laseru tipa Bistronic laser, (2000), BISTAR 3015. Varirani su parametri srednje snage lasera, brzina lasera, pritisak gasa i položaj fokusa. Na osnovu dobijenih geometrijskih karakteristika rezova i površinske morfologije diskutovani su i određeni optimalni parametri. Laserom zavareni spojevi limova legure Nimonik 263 su, osim mikroskopskih i profilometrijskih ispitivanja površina, ispitivani i metodom sa razaranjem. Prilikom laserskog deformacionog ojačavanja uzorci su bili izloženi laserskom svetlu na talasnoj dužini od 1064 nm i 532 nm, sa brojem akumuliranih impulsa: 50, 100 i 200. U svim delovima eksperimenta strukturna analiza superlegure Nimonic 263 izvedena je pomoću svetlosne mikroskopije (SM), skenirajuće elektronske mikroskopije (SEM) i EDS-analize. Merenja mikrotvrdoće vršena su pomoću metode Vikersa pod opterećenjem od 9,81N. Profilometrija je izvedena na beskontaktnom profilometru Zygo NewView 7100.

Cooling time in the temperature range 800 - 500°C has a great effect on the structures that arrise in the heat affected zone of welds steel. Data on optimal cooling time t8/5 for the certain steels can be found in the literature. The period of the cooling time t8/5, during the welding of the particular joints, in addition to the thickness and physical properties of welded steel, depends on shape of the weld, the welding process and welding parameters as well. In this work, the procedure for the selection of welding parameters for a butt joint welded to the microalloyed steel P 460 NL1 is presented. The microstructure in the heat affected zone and the results of measurement of their hardness are showed and analysed. It is concluded that the welding parameters selected with the help of cooling time t8/5 provide the satisfactory structure and hardness of welds.

Austenitic materials have high demand in modern manufacturing industries due to their improved technological characteristics such as high mechanical strength and hardness, corrosion resistance, heat resistance and wear resistance. Some applications of austenitic materials include elevated pressure and temperature, and require stringent design requirements and close tolerances in manufactured products. Laser cutting is one of the non-conventional cutting processes, used to obtain complex shapes and geometries. In this paper, laser cutting was performed on austenitic material. The laser cutting process parameters are varied with the aim to obtain the optimal process parameters. The geometric and metallurgical characteristics of the cut parts are investigated and compared to the conventional cutting methods of austenitic materials.

Laser shock peening is an innovative surface treatment technique, which has been successfully applied to improve fatigue performance of metallic components. Laser shock peening improves the surface morphology and microstructure of the material. In this paper, three Nd3+:YAG laser process parameters (voltage, focus position and pulse duration) are varied in an experiment, in order to determine the optimal process parameters that could simultaneously meet the specifications for seven correlated responses of processed Nimonic 263 sheets. The modelling and optimisation of a process were performed using the advanced, problem-independent method. First, responses are expressed using Taguchi’s quality loss function, followed by the application of multivariate statistical methods to uncorrelate and synthesise them into a single performance measure. Then, artificial neural networks are used to build the process model, and simulated annealing was utilised to find the optimal process parameters setting in a global continual space of solutions. Effectiveness of the proposed method in the development of a robust laser shock peening was proved in comparison to several commonly used approaches from the literature, resulting in the highest process performance measure, the most favourable response values and the corresponding process parameters optimum. Besides the improved surface characteristics, the optimised laser shock peening (LSP) showed an improvement in terms of microhardness and formation of favourable microstructural transformations.

Hyperbaric Oxygen Therapy (HBOT) is a method used to administer pure oxygen at a pressure which is greater than atmospheric pressure in order to increase the concentration of O2 in the tissues, blood and cells, and correct or improve certain conditions. The hyperbaric chamber is a medical instrument that provides many benefits to the economy and health protection. They are in fact pressure vessels, subjected to the higher stress levels. In this paper, the stress and deformation state of different multiplace hyperbaric chambers are determined. Stress and deformation states are calculated for different geometry models using ABAQUS. Therefore, the aim of this paper is to define the weakest points in the chambers of different geometry with the use of the Finite Element Method.

The principles and examples of state-of-the-art experimental methods for measuring the fracture mechanics parameters are presented in this paper. The methodology of experimental analysis of the fracture mechanics parameters includes investigation of fracture behaviour of metallic materials using modified specimens with initial crack under tensile load, with the primary goal of determining the characteristics of fracture processes for the case of thin plates, using basic fracture mechanics postulates. The methodology also includes the application of experimental fracture mechanics procedures as defined by standards, using three-dimensional stereo-metric mechanical behaviour measurement methods. Fracture behaviour of metallic materials, mainly 316L stainless steel and titanium alloy Ti-6Al-4V specimens, is analyzed by using a digital image correlation (DIC) system for measuring strain and displacement in the material. GOM three-dimensional optical system and Aramis software are used to perform experimental analysis of selected specimens. As this system is used to measure strain and crack tip opening displacement (CTOD) parameter on the modified compact tension specimen C(T) and notch specimens, a basic review of measuring procedures and result processing is given, alongside other possible applications for this system. The presented results show strain and displacement fields during crack tip opening, crack growth, and the moment of fracture of specimens, which are not possible using traditional measurement methods. The analysis of results shows that it is possible to measure displacements during crack tip opening with a great precision, and thus obtain the CTOD parameter. The results show that the selected measuring method obtains good results in the analysis of mechanical behaviour and fracture mechanics parameters of metallic materials.

This paper presents a hybrid design strategy for the determination of the optimum laser drilling parameters which simultaneously meets the requirements for seven quality characteristics (responses) of the holes produced during pulsed Nd:YAG laser drilling of a thin sheet of nickel-based superalloy Nimonic 263. The process was designed using two approaches based on the experimental data. In the first approach, the quality losses of seven correlated responses were uncorrelated into a set of components using the principal component analysis; then the grey relational analysis was applied to synthesise components into a synthetic performance measure. Since this approach considered only parameter values used in the experiment, the second approach was developed to find the global optimal parameters solution using an artificial neural network to model the relation between parameters and a synthetic performance measure, and a genetic algorithm to perform a search for the global optimum in a continual multidimensional space. The analysis of the application indicated that the proposed approaches gave a better result, in terms of the optimal parameter settings that yield the maximal synthetic performance measure, than several commonly used methods for multi-response process parameters design. The results demonstrated that the robust Nd:YAG laser drilling of Ni-based superalloy sheets was designed with respect to the requirements for seven quality characteristics of the drilled holes, by using the proposed strategy.

Inspekcija cevovoda u eksploataciji i analiza uzroka otkaza

Due to the specific conditions of manufacturing, processing and utilization of nickel-base superalloys, the implementation of contemporary precision techniques is necessary in the research of the alloys features. Multi-component nickel-base superalloys, with about of 50% of nickel content, are commonly exploited in the conditions of high temperatures and pressures as well as in various aggressive operating environments. For successful quality control, which includes the monitoring of the changes in the alloy microstructure, fine-scale structure investigations are necessary. In this work, the samples of nickel-base superalloys have been exposed to 800 nm femtosecond laser in various operating regimes. Surface damages and dents caused by femtosecond laser pulses have been observed by optical and scanning microscopy.

The paper presents a study on the surface modifications of nickel based superalloy Nimonic 263 induced by laser shock peening (LSP) process. The process was performed by Nd3+:Yttrium Aluminium Garnet (YAG) picosecond laser using the following parameters: pulse duration 170 ps; repetition rate 10 Hz; pulse numbers of 50, 100 and 200; and wavelength of 1064 nm (with pulse energy of 2 mJ, 10 mJ and 15 mJ) and 532 nm (with pulse energy of 25 mJ, 30 mJ and 35 mJ). The following response characteristics were analyzed: modified surface areas obtained by the laser/material interaction were observed by scanning electron microscopy; elemental composition of the modified surface was evaluated by energy-dispersive spectroscopy (EDS); and Vickers microhardness tests were performed. LSP processing at both 1064 nm and 532 nm wavelengths improved the surface structure and microhardness of a material. Surface morphology changes of the irradiated samples were determined and surface roughness was calculated. These investigations are intended to contribute to the study on the level of microstructure and mechanical properties improvements due to LSP process that operate in a picosecond regime. In particular, the effects of laser wavelength on the microstructural and mechanical changes of a material are studied in detail.

Pressure vessels are, according to the degree of risk that present for humans and the environment, divided into the vessels of high and low level of hazard. One of the most important aspects of the conformity assessment of the new pressure equipment and for the evaluation of their safety for work, are nondestructive testing of welded joints. Given the importance and responsibility carried by these tests, the extents of nondestructive testings are recomanded by the standards depending on the type of welded joint and testing group of materials. However, the recomanded extent of tests are the result of analysis and experience, and are subject to change over the years. In this paper, the changes in the extent of nondestructive testing of welded joints in relation to the EN 13445-5: 2009 and EN 13445-5: 2015 are analysed depending on the groups of materials and the type of welded joint of pressure vessels, with reference to the practical examples.

The investigation was performed on nickel-base superalloys, with nickel being the most influential alloying ingredient. After thermo-mechanical preparation and corresponding processing, femtosecond laser beam machining has been performed. The laser wavelength was 800 nm. The exposition time, during which the samples have been exposed to the pulses of femtosecond laser beam varied, as well as the average output power. The changes of both the output power and the exposition time enabled the samples to be irradiated with dierent total energy during each exposition. The changes in samples microstructure were observed with optical and scanning electron microscopy, with energy-dispersive spectrometry, and analyzed as well. Microhardness measurements of both base material and ablated spots have been performed. PACS numbers: 01.55.+b, 42.62.-b, 81.05.Bx

The investigation presented in this paper was carried out on the nickel-based superalloy, Nimonic 263, a material widely used at elevated temperatures and pressures. The samples were exposed to a Nd3+:YAG pulsed laser, at a wavelength of 1064 nm and a pulse duration of 170 ps, and the estimated threshold damage was 2 mJ. Different pulse energies and numbers of pulses were applied in air and helium-enriched atmospheres. Spots obtained by the laser interaction with the material were observed by optical and scanning electron microscopes and analyzed by energy-dispersive spectroscopy. Vickers microhardness tests were performed. In this paper, the changes that had occurred at the sample surface microstructure as a result of laser-material interaction are discussed with the aim of contributing to the determination of optimal laser parameters in the laser surface treatment process. 3rd International School and Conference on Photonics, Aug 29-Sep 02, 2011, Belgrade, Serbia

We investigate samples of austenitic materials - stainless steel and iron-based superalloy - which are widely used at high temperatures and pressures. The samples were exposed to Nd(3+):YAG laser pulses with a wavelength of 1064 nm and a pulse duration of 170 ps. We employ different pulse energies and number of pulses. The spots appearing after the laser irradiation were examined by optical and scanning electron microscopy and analyzed by energy-dispersive spectroscopy. We also perform Vickers microhardness tests. We discuss the microstructure changes caused by different energy and number of pulses in air and in a He-enriched atmosphere with the aim to determine optimum laser parameters in surface-treatment technology.

Owing to their excellent mechanical and physical characteristics, superalloys are the most suitable material for use in hot sections of aircraft engines. Thousands of holes need to be drilled in constructive parts of machines, with laser technique emerging as the most effective. Laser drilling has been used to produce small diameter, accurately positioned holes, with little damage in regions around them, and in various materials. Effective laser employment of drilling of high quality holes for critical applications highly depends on correct selection and optimization of laser drilling parameters. In this work, the holes were drilled by a pulsed Nd3+:YAG laser, with maximum average power of 160 W, in superalloy Nimonic 263 sheets, thickness 0,7 mm and 1,2 mm. The holes were observed by optical and scanning electron microscope. Geometrical characteristics of laser drilled holes that depend on laser parameters were investigated and analysed. The aim of this investigation was to find optimal laser parameters which would produce as much as possible regular holes., Zbog svojih odličnih mehaničkih i fizikalnih značajki, superlegure su najpogodniji materijal za uporabu u toplim sekcijama zrakoplovnih motora. U konstrukcijskim dijelovima strojeva treba izbušiti tisuće rupa, za što se kao najučinkovitija pokazala laserska tehnika. Bušenje laserom koristi se za proizvodnju malih promjera, točno pozicioniranih rupa, s malim oštećenjima u području oko njih i u različitim materijalima. Učinkovita uporaba lasera za bušenje rupa visoke kvalitete za kritične primjene uvelike ovisi o ispravnom izboru i optimiranju parametara bušenja laserom. U ovom radu, rupe su izbušene Nd3+:YAG impulsnim laserom, uz maksimalnu prosječnu snagu od 160 W, u limovima superlegure nikla Nimonic 263, debljine 0,7 mm i 1,2 mm. Rupe su promatrane optičkim i skenirajućim elektronskim mikroskopom. Istražene su i analizirane geometrijske značajke laserski bušenih rupa, koje ovise o parametrima lasera. Cilj ovog istraživanja bio je pronaći optimalne parametre lasera koji bi omogućili što pravilnije rupe.

Pulsed laser treatments induce changes in the microstructure of materials. We have exposed the Nimonic-263 superalloy to pulsed laser beams of various repetition rates and wavelengths and investigated the changes in microstructure and microhardness. Two types of laser treatment of the material surface occurred: mechanical and thermomechanical. The microstructure changes have been comparatively analyzed by scanning electron microscopy and energo-dispersive spectrometry. The grain size was measured before and after the treatment and microhardness tests were performed. These investigations aim to contribute to the study of the level of improvement of microstructure and mechanical properties because of the interaction with laser beams.

164 161 М60 М63 In this work, biochar originating from paper fibres was examined. Biochar was prepared via pyrolysis method at 550°C. Oxygen-containing functional groups on biochar surface were determined. The surface functional groups of biochar were analysed by Fourier transform infrared spectroscopy. The amount of oxygen-containing functional groups was performed with Boehm titration. The total acidity of biochar was mostly attributed to carboxylic and lactonic groups.

Depending on the person's desires and needs, he or she uses different techniques of manipulation to make it easier to achieve the goals set. With the techniques of manipulation in interpersonal relations, certain psychological phenomena and psychological principles are also recognized. The paper deals with the features of impression management during conscious use of manipulation techniques and of key, intrinsic factors in the impression management. We provide an overview of key factors, as well as their features. The terminology that equates self-representation and impression management is explained. The paper also deals with those manipulation techniques that can be used as an indirect self-representation tactics, with an additional focus on lobbying as a relatively unrecognized tactic in this area. Ultimately, self-indulgence and work on themselves contribute to the improvement of the desired image, projection, and control of the notion of self.

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The concept of observation of landslide displacement in time and space using geotechnical instruments is standard in engineering practice, but the use of remote (satellite) technologies for obtaining continual slid data is a new area of research. The usual instruments used in geotechnics for landslide observations such as inclinometers or extensometers are not fully adequate for observing large areas of potential slip or active landslides. Advanced remote sensing methods should be such as to avoid the weaknesses of classical methods, sufficiently accurate and, if possible, continuous data collection. It is desirable to combine different observation techniques to ensure that accurate and reliable data on sliding development is obtained. The paper presents the classic methods of observation of landslides as well as the basic features of innovative remote sensing methods, illustrating examples from the application of these.

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