Echinochloa crus-galli (L.) P. Beauv. is the most common monocotyledonous weed in maize crops in Croatia. Crop–weed interference is influenced by weed emergence patterns, and knowledge of the timing ...of weed emergence is crucial for the development of an efficient integrated weed-management program. Therefore, two-year field experiments were conducted in a maize crop sown in early May in continental Croatia to determine the emergence pattern of E. crus-galli from natural seedbank. In laboratory studies, the estimated base temperature and base water potential for the Croatian ecotype of E. crus-galli were 10.8 °C and −0.97 MPa, respectively. Then, the estimated germination parameters were compared with the values embedded in the AlertInf model from Italy (Veneto) to calibrate this hydrothermal model. The estimated hydrothermal units were around 28 for the onset (10%) and 93 for the middle (50%) emergence of E. crus-galli. Our findings showed that the AlertInf model satisfactorily simulated the emergence of E. crus-galli in maize crop in Croatia (EF = 0.97 in 2019 and 0.98 in 2020), indicating its potential use in other geographical areas
Effective weed management depends on correct control timing, which depends on seedling emergence dynamics. Since soil temperature and soil moisture are the two main factors that determine weed ...germination, the hydrothermal time model can be used to predict their emergence. The aim of this study was to estimate the base temperature (Tb) and base water potential (Ψb) for the germination of Chenopodium album, Amaranthus retroflexus, Setaria pumila, and Panicum capillare collected from fields in continental Croatia and then to compare these values with those of Italian populations embedded in the AlertInf model. Germination tests were performed at seven constant temperatures (ranging from 4 to 27 °C) and eight water potentials (0.00–1.00 MPa). The estimated Tb and Ψb were 3.4 °C and −1.38 MPa for C. album, 13.9 °C and −0.36 MPa for A. retroflexus, 6.6 °C and −0.71 MPa for S. pumila, and 11.0 °C and −0.87 MPa for P. capillare, respectively. According to the criterion of overlap of the 95% confidence intervals, only the Tb of C. album and the Ψb of A. retroflexus of the Croatian and Italian populations were similar. Further field experiments should be conducted to monitor the weed emergence patterns of C. album and calibrate the AlerInf equation parameters.
The aim of this work was to examine the dependence of the local surface structure (surface structural heterogeneity) on the local thickness (thickness uniformity) and structure properties along the ...thickness of hydroxyapatite coatings (HACs) deposited by using the high power (52 kW) laminar plasma jet. For the deposition process, a relatively small size of the feedstock hydroxyapatite powder (HAP) (33 μm) was used. The HACs were deposited at different stand-off distances (SODs) (80, 100, and 150 mm) without preheating of substrates. The thickness measurements were performed by using the calibrated micrometer and light microscopy (LM). The surface micro-structure was analyzed by using the micro-Raman spectroscopy (MRS), whereas the micro-structure along the thickness of HACs was studied by using the MRS, X-ray powder diffractometry (XRPD), and LM (combined with chemical etching). The results showed a heterogeneous phase distribution on the surface of each HAC analyzed as well as the non-uniform thickness of HACs. Apparently, a correlation existed between the local surface structure and the local thickness of HACs. However, the MRS, XRPD, and LM analyses of micro-structure along the thickness of HACs indicated that the differences in the local surface structure could be related to the different recrystallization established during the plasma deposition process in the different parts along the thickness of each HAC analyzed.
•Hydroxyapatite coatings (HACs) were deposited by high power laminar plasma jet.•Each HAC exhibited surface structural heterogeneity and non-uniform thickness.•The local surface crystallinity changed in accordance with local thickness of HACs.•The last implied correlation between local surface structure and local thickness.•However, local surface structure was depended on local recrystallization conditions.
Homogeneous films from SiOx (x = 1.2, 1.3) were deposited on crystalline Si substrates by thermal evaporation of silicon monoxide in vacuum. A part of the films was further annealed at 1000 °C to ...grow Si nanocrystals in a silicon dioxide matrix. Homogeneous and composite films with initial x = 1.2 were irradiated by 20-MeV electrons at a fluence of 3.6 × 1015 electrons/cm2 and the effect was compared with that caused by irradiation of films with x = 1.3 at much lower fluence of 2.4 × 1014 electrons/cm2. Transmission electron microscopy, infrared transmission and Raman spectroscopies and spectroscopic ellipsometry were used to get information about the SiOx films composition, nanoparticle crystallinity and space distribution as well as for electron-beam induced changes in the nanocrystal size. The infrared data have indicated that electron irradiation with 3.6 × 1015 electrons/cm2 induced phase separation in the homogeneous films with x = 1.2. Not only silicon nanocrystals but also a small amount of amorphous silicon phase have been detected in the composite films before and after electron irradiation. Nanocrystallite size decrease induced by the electron beam irradiation at a fluence of 3.6 × 1015 electrons/cm2 has been assumed on the basis of the observed changes in the effective refractive index, extinction coefficient and nanocrystallite volume fraction in the composite films.
The aim of the research was to determinate the degree of variation in morphological (seed weight) and functional polymorphism (final germination, dormancy, seed mortality and germination dynamic) ...within two seed populations of Ambrosia artemisiifolia L. Seeds were collected separately from 20 plants/population in Jastebarsko (45°40'18˝N; 15°39'03˝E), population-J and Popovača (45°34´1˝N; 16°40´43˝E), population-P in 2014. Seed weight of J and P populations had weak variability (CV-J = 18.2%, CV-P= 29.8%) with an average of 4.05 g (J) and 4.54 g (P). Estimated variability was strong for amount of death seeds in the J (CV = 67.6%), but weak for geminated (CV = 4.9%) and moderate for dormant seeds (CV = 51.0%). Variability within P population was moderate for both germinated and dead seeds (CV = 34.5%; 34.1%), while variability within amount of dormant seeds was weak (CV = 14.2%). Variability in medium germination (T50) was relatively low for both experimental populations (CV – J = 12.0%; CV – P = 22.4%). Despite determined intrapopulation variation, degrees of variability between researched parameters (final germination, dormancy and medium germination – T50) were weak or moderate and therefore acceptable for further experiment base on seed testing.
The study comprehensively investigates the design and performance of self-cleaning surfaces fabricated by coating aluminum foil with an acrylic paint matrix enriched with different content of ...titanium dioxide (TiO2) nanoparticles. The main goal was to assess the self-cleaning characteristics of the surfaces obtained. This study employs scanning electron microscopy (SEM) to analyze the morphology of TiO2-modified acrylic surfaces, revealing spherical particles. Raman spectroscopy elucidates signatures characterizing TiO2 incorporation within the acrylic matrix, providing comprehensive insights into structural and compositional changes for advanced surface engineering. Alternating current (AC) impedance spectroscopy was used to assess selected charge transport properties of produced self-cleaning surfaces, allowing us to gain valuable insights into the material’s conductivity and its potential impact on photocatalytic performance. The self-cleaning properties of these tiles were tested against three frequently used textile dyes, which are considered to pose a serious environmental threat. Subsequently, improving self-cleaning properties was achieved by plasma treatment, utilizing a continuous plasma arc. The plasma treatment led to enhanced charge separation and surface reactivity, crucial factors in the self-cleaning mechanism. To deepen our comprehension of the reactive properties of dye molecules and their degradation dynamics, we employed a combination of density functional tight binding (DFTB) and density functional theory (DFT) calculations. This investigation lays the foundation for advancing self-cleaning materials with extensive applications, from architectural coatings to environmental remediation technologies.
Photocatalytic degradations of tricyclic antidepressive amitriptyline (AMI) in aqueous solutions under UV irradiation were performed using TiO
2
and TiO
2
/WO
3
coatings, as photocatalysts. Coatings ...were formed on a pure titanium substrate using plasma electrolytic oxidation (PEO). The effects of chosen synthesis parameters on structural properties of prepared coatings have been investigated using micro-Raman spectroscopy and non-contact atomic force microscopy. Raman scattering measurements showed that coatings contain different amounts of crystalline anatase TiO
2
and monoclinic WO
3−x
phases, as well as amorphous and/or disordered phases of both oxides. Also, results indicated that coatings’ surface become more disordered and inhomogeneous with increasing duration of the PEO. The coating T/W(45 s) prepared during 45 s of PEO has shown the highest efficiency in the UV-driven removal of AMI. T/W(45 s) showed slightly decrease in photodegradation efficiency after four successive runs. The results showed that the degradation of AMI led to the formation of ionic by-products (nitrite, nitrate, ammonium ion, acetate, and formate), whereas degree of mineralization was the highest (38.8%) using coating T/W(45 s) after 120 min of irradiation. Also, there was no significant toxicity observed after irradiation of AMI solutions using different coatings on four mammalian cell lines: rat hepatoma, mouse neuroblastoma, human colon adenocarcinoma, and human fetal lung.
Huds. is an important pinoxaden-resistant grass weed in many countries of Europe. Recently, the low efficacy of pinoxaden was reported in winter cereals in Croatia, but a preliminary dose-response ...trial showed no herbicide resistance for the investigated weed population. Therefore, a two-year experiment was conducted under greenhouse conditions to determine the efficacy of various pinoxaden doses (20, 40 and 80 g a.i. ha
) on weed visual injuries and biomass reduction after herbicide application at different growth stages. As expected, the maximum weed biomass reduction (97.3%) was achieved by applying the highest dose (80 g a.i. ha
) at the earliest growth stage (ZCK 12-14). A pinoxaden dose of 20 g a.i. ha
resulted in satisfactory weed biomass reduction (88.9%) only when applied at ZCK 12-14. The recommended dose (40 g a.i. ha
) also provided sufficient weed control up to the growth stage ZCK 21-25. Slightly delayed (ZCK 31-32) application of the recommended dose brought about a low weed biomass reduction (60.1%). Double than the recommended dose also failed to provide satisfactory weed control at the advanced weed growth stages (ZCK 31-32 and ZCK 37-39). Thus, reported low efficacy of pinoxaden is most likely because of delayed herbicide application when
is overgrown.
The scope of this paper is temperature dependence of Raman spectra in several nanocrystalline materials and iron‐based single‐crystals. The Raman results presented and analyzed here are related to ...TiO2 nanopowders (with dominant anatase and brookite phase) and ZnxCd1−xSe single layers measured at different temperatures. Temperature‐dependent Raman spectra of iron‐based sulphides and selenides (BaFe2S3 and BaFe2Se3), as well as alkali‐doped iron selenides (KxFe2−ySe2 and K0.8Fe1.8Co0.2Se2) are also analyzed. A physical model, including thermal expansion as well as three‐ and four‐phonon anharmonic effects, is used to quantitatively analyze temperature evolution of the characteristic Raman mode self‐energies for the materials of interest. It is demonstrated how this model can be used as a tool for predicting the temperature of structural and phase transitions, with critical scrutany of its limitations.
Presented results show how temperature‐dependent Raman scattering measurements could be used in the analysis of temperature variation of structural, morphological, compositional, electronic, and/or magnetic material properties. A model including quasiharmonical and anharmonical contributions is used to quantitatively analyze experimental temperature dependence of energy and linewidth of the characteristic Raman modes of nanostructured and iron‐based materials.
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