The efficient biomass energy use is a key prerequisite for the implementation of renewable energy development strategies on a regional level. For the highly efficient energy use in the combustion ...process, it is necessary to properly regulate the process based on its precise description. The paper aim is to evaluate whether dynamic time warping (DTW) methods can be used for this description, as well as for the recognition of the specific operating state of a biomass boiler. For the DTW analysis, operating records of more than 10 hours of a laboratory biomass boiler (
= 25 kW) were used, including an emission analysis, for which the operating modes were intentionally alternated in order to identify the stable and transient states of boiler operation. Based on the results, it can be stated that the identical partial operating sections of the controlled variables can be reliably identified in the operating variables of boiler by means of the DTW method, since its manifestations of operating regulation showed compliance with the given operating state, and it is possible to identify a partial quantity for estimating the total operating boiler state.
Hot-dip galvanized coatings represent a protection based on passivation of the single zinc layer. It is one of the most commonly used surface treatments of steel. However, pure zinc forms merely an ...insignificant upper layer. Coating crosscut is formed by intermetallic phases that can cause decrease in the level of anticorrosion protection. This results from an iron diffusion from the base material. Goal of this paper is to analyse the changes in the mechanical properties of these phases in relation to zinc coating heat treatment. For the experiment, annealing temperatures of 200 °C and 300 °C were used, and the staying time was set at 1, 3 and 5 hours. Furthermore, samples without any heat treatment were subjected to comparison as well. Moreover, following tests were conducted: bending test in compliance with the ČSN EN ISO 1519 standard, and tearing test (in accordance with the ČSN EN ISO 4624 standard). On the basis of performed tests, the changes in mechanical properties of the zinc coating after heat treatment could be analysed.
Cilj istraživanja bio je utvrditi promjene i povezanost fizikalno-kemijskih pokazatelja, broja somatskih stanica (BSS) i kvalitete gruša tijekom laktacije ovaca Lacaune pasmine. Istraživanje je ...provedeno na osamnaest ovaca druge laktacije na ekološkoj farmi u Valaškoj Bistrici (Republika Češka). Utvrđeno je da je stadij laktacije statistički značajno utjecao na gotovo sve istraživane pokazatelje osim na pH, titracijsku kiselost, BSS i kvalitetu gruša. Sadržaj suhe tvari, masti, ukupnih proteina, kazeina, Ca i P se povećavao, a dnevna količina mlijeka i sadržaj laktoze su se smanjivali s trajanjem laktacije. Stadij laktacije imao je značajan utjecaj na vrijeme koagulacije koje se povećavalo s trajanjem laktacije. Produženje vremena koagulacije bilo je pozitivno povezano sa sadržajem suhe tvari, kazeina i Ca. Za razliku od tog, stadij laktacije nije značajno utjecao na kvalitetu gruša, kao što nisu ni utvrđene značajne korelacije između kvalitete gruša i ostalih pokazatelja, osim za vrijeme koagulacije (r=0,40). Može se zaključiti da su ovce Lacaune pasmine imale zadovoljavajuću proizvodnju mlijeka te fizikalnokemijske i tehnološke pokazatelje mlijeka usprkos ekstenzivnoj ishrani.
A comparison of two independent photovoltaic (PV) systems located close to each other on the south of the Czech Moravian Highland was accomplished. Due to differences in installation parameters; ...reference quantities were used to calculate transformed data sets for specific production performances comparison. Differences in monthly and annually daily production were performed by t-test.According to obtained results, it was concluded that annually mean daily productions per 1 kWp of installed capacity and per 1 m2 of active area of the panels are significantly better by single crystal silicon installation in tracking system than by stable installation of a different technology of single crystal silicon. However, comparing this performance per 1 m2 of occupied land by studied power-plants the stable installation performed higher production rates on daily mean basis in majority of months of the year 2010 as well as by annually mean daily production.
Heat and mechanical resistance of zinc coating Horák, Karel; Černý, Michal; Filípek, Josef ...
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis,
9/2014, Volume:
58, Issue:
4
Journal Article
Peer reviewed
Open access
The article is aimed at studying the effect of temperature on structure of intermetallic phases of the protective zinc layer. The main objective of the article is a description of the structure and ...the changes that can occur during the heating process. The first part of the article deals with the description of the structure and mechanical properties of the interfacial phases and their arrangement. The main part of the article is aimed at study of brittle intermetallic phases, which arise due to increased temperature. For this reason, a set of samples of steel CSN 11 321 (DC01) was prepared. These samples were subjected to thermal heating in the tempering furnace. Subsequently metallographic cross sections were prepared, observed and assessed using SEM microscopy and EDS analysis. Also accelerated corrosion tests and pull off bend tests were performed. Conclusion of the article is trying to explain the influence of intermetallic phases on degradation of the protective layer.
The aim of the article is to demonstrate the effect of setting the length of the upper link of the three-point hitch on the change in the load of the in-furrow wheel and the on-land wheel of the ...tractor during ploughing. Furthermore, attention is paid to the load on the rear wheels together with the tyre inflation pressure and their effect on the contact pressure under the tractor wheels. The tractor’s inclination, in combination with the force and moment effects of ploughing, may not always lead to large differences in the contact pressures of the rear in-furrow and on-land wheels. The results for the tractor-mounted plough set showed the possibilities of balancing the load on the rear wheels of the tractor when changing the length of the upper link of the three-point hitch. For semi-mounted ploughs, changing the length of the link will not affect the difference in the load on the rear wheels of the tractor. The kinematic linkage of the semi-mounted plough suspension transmits the moment from the plough support wheel and loads the wheel in the furrow more. The results further document that the proper suspension of the ploughs and, in particular, the appropriate choice of tyre inflation pressure can achieve substantial changes in the contact pressure under the rear wheels of a plough tractor.
Agricultural soil processing belongs to the basic elements in the process of crop production. Currently classic tillage method is decreasing and the only trend has stated as a shallow plowing. ...Suitable post harvest soil tillage greatly affects yields in the next cycle. The aim of the study is the analysis of abrasive wear of selected construction materials and their subsequent use for DXRV-HD cultivator. The performed tests are focused on monitoring the mechanical properties of the materials and their use for variable cutting tip of cultivator body. Tested materials are divided into four categories. These materials include tool steel (19436), carbon steel (12050), cast iron with globular graphite and welding material supplied as a functional complex on low carbon steel by the Abraweld company. These materials are tested together with the original part of share cultivator. The present experiment is focused on metallorgraphic, mechanical and abrasive analysis. Structural component of the material is identified by metallographic photos and then compared with the impact strength tested on Charpy hammer. Followed the abrasion resistance according to CSN 01 5084 and the total evaluation of the tested samples are done.
This study monitored the influence of milk samples temperature on the measuring accuracy of FT-NIR spectroscopy in milk content analysis. Reference methods were used to determine dry matter, fat, ...protein, and lactose content in cow's milk. Milk samples were measured in reflectance mode on an integrating sphere with the use of a compression cuvette and a transflectance cuvette, ensuring a beam trajectory length of h = 0.2 mm. The samples were measured at 18, 20, 22, 24, and 40°C, and analyses were performed at 100 scans at a resolution of 8 cm-1. The measurements were influenced by the temperatures of the samples during the evaluation of all analyzed constituents (P < 0.05). Our results confirmed that the accurate determination of milk constituents requires maintaining, during analysis, the temperature conditions of the samples and the conditions for which the spectrophotometer calibration was designed.
The paper is dedicated to identification of sources of acoustic emission generated during static bending test of wood specimen. Information on wood structure, wood failure behavior and ...computer-generated finite element method (FEM) simulation of static bending test were used to localize and estimate power of individual acoustic emission sources. Significant acoustic emission sources are expected in the specimen in two areas: under the upper central support (during the entire bending test run) and in the tension portion of the specimen at the centre of lower baseline (at the fracture/destruction time). Strong acoustic emission sources were registered in tension portion of the specimen in direct connection with final fracture of specimen.
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