The paper aimed at evaluating the effects of biochar (BC) produced by slow pyrolysis of vine pruning residue on soil physicochemical properties and tomato plant growth. A greenhouse experiment was conducted for 66 days, applying different treatments for 3 soil types, i.e., foliar fertilizer, BC (at a volumetric ratio between BC and soil of 20/80), BC + foliar fertilizer, and no treatments. Strongly alkaline BC (pH = 9.89 ± 0.01) had a significant beneficial effect on the growth performance of tomato plants sown in a strongly acidic soil (pH = 5.40 ± 0.02). The mean values of height, number of leaves, and collar diameter of plants grown in BC-amended soil without foliar treatment were up to 50% higher than those of plants grown in soil with the other treatments. This positive effect of BC on plant growth is due to the changes in the soil properties. The addition of BC led to increased values of electrical conductivity, pH, soluble and available nutrient concentration. Moreover, BC reduced soil bulk density by about 50%, resulting in improved plant root development and thus enhanced water and nutrient uptake. Accordingly, BC derived from vine pruning residues can improve soil quality and tomato plant growth, as well as reduce biomass residues.

The agronomic benefits of biochar (BC) prepared by slow pyrolysis of vine pruning residues, which are produced in large quantities in Romania, were evaluated. Three soil types, i.e., slightly alkaline fluvisol (S1), slightly acidic chernozem (S2), and strongly acidic luvisol (S3), with mean values of pH of 7.99, 6.26, and 5.40, were amended with BC at a volumetric ratio between BC and soil of 20/80. A greenhouse experiment was performed for 109 days to assess the effects of BC amendment on bell pepper growth. The following treatments were applied: foliar fertilizer, BC, BC + foliar fertilizer (using two concentrations of foliar fertilizer solution), and a control. Strongly alkaline BC (pH of 9.89 ± 0.01) had a significant positive effect on the growth performance of bell pepper plants sown in the strongly acidic soil S3. The mean values of height, collar diameter, number of leaves, and root volume of plants grown in BC-amended soil S3 without foliar treatment were significantly higher (13–72% and 14–33%, respectively) than those of plants grown in non-amended soil S3 without and with foliar treatment. This beneficial effect of BC on bell pepper plant growth was due to the changes in the soil properties. BC significantly increased (up to eight times) electrical conductivity, pH, soluble phosphorus, potassium, and ammonium nitrogen concentrations of soil S3, and decreased its bulk density by 51%, resulting in improved water/nutrient uptake and plant growth performance. BC had no favourable effect on the growth parameters of bell pepper plants sown in slightly alkaline soil S1, and slightly acidic soil S2.

The paper aimed at studying the slow pyrolysis of vine pruning waste in a fixed bed reactor and characterizing the pyrolysis products. Pyrolysis experiments were conducted for 60 min, using CO₂ as a carrier gas and oxidizing agent. The distribution of biochar and bio-oil was dependent on variations in heat flux (4244–5777 W/m²), CO₂ superficial velocity (0.004–0.008 m/s), and mean size of vegetal material (0.007–0.011 m). Relationships among these factors and process performances in terms of yields of biochar (0.286–0.328) and bio-oil (0.260–0.350), expressed as ratio between the final mass of pyrolysis product and initial mass of vegetal material, and final value of fixed bed temperature (401.1–486.5 °C) were established using a 2³ factorial design. Proximate and ultimate analyses, FT-IR and SEM analyses, measurements of bulk density (0.112 ± 0.001 g/cm³), electrical conductivity (0.55 ± 0.03 dS/m), pH (10.35 ± 0.06), and water holding capacity (58.99 ± 14.51%) were performed for biochar. Water content (33.2 ± 1.27%), density (1.027 ± 0.014 g/cm³), pH (3.34 ± 0.02), refractive index (1.3553 ± 0.0027), and iodine value (87.98 ± 4.38 g I₂/100 g bio-oil) were measured for bio-oil. Moreover, chemical composition of bio-oil was evaluated using GC-MS analysis, with 27 organic compounds being identified.

Non-aerated compost tea (CT) was prepared from compost derived from rockweed (Ascophyllum nodosum) and fish (cod, common ling, haddock, saithe) residues that fermented in water. Electrical conductivity, pH, concentrations of dry matter, ash, C, macronutrients (N, P, K, Ca, and Mg), and micronutrients (Cu, Fe, Mn, Mo, and Zn) of CT prepared under different fermentation conditions were measured. The effects of process factors, i.e., water/compost mass ratio (4.2–9.8 g/g) and fermentation time (4.2–9.8 days = 100–236 h), on the physicochemical properties of CT were quantified using quadratic polynomial models. CT obtained at optimal levels of process factors (4.2 g/g and 5.6 days = 134 h) was tested for lettuce seed germination and seedling growth. Diluted CT (25% CT + 75% ultrapure water) improved seedling growth while achieving a high germination percentage (97%).

The present work focuses on the problem of steel surface corrosion as a kinetic expression when water droplets are repeatedly deposited and evaporated on/from its surface. This process, together with the rainwater film corrosion process, belongs to the theoretical foundations of the problem of atmospheric corrosion. It was considered that the formation of water droplets on surfaces is a random but repetitive process, as well as the fact that experimental and theoretical observations show that the droplet corrosion front of a metal surface is located in its zone circumference. We thus aimed to establish how the corrosion process evolves on a steel plate when many drops are deposited and removed repeatedly. An experimental setup and working procedure were used to obtain data characterizing the simultaneous process of steel surface corrosion and water droplet evaporation. For natural convection conditions with a variable relative humidity and temperature environment, an extensive data set consisting of the dynamics of individual droplet evaporation coupled simultaneously with the corrosion of the steel surface under the droplet was obtained. The mathematical models for evaporation and corrosion under the droplet have the same dynamic transfer surface for water evaporation and oxygen supply in the droplet. An approach for determining this surface depending on the momentary droplet mass was considered. Several simultaneous measurements of evaporation–corrosion dynamics were used to calibrate the coupled models, which were then used to show their compatibility with experimental data.

The paper focuses on the experimental investigation and mathematical modeling of the corrosion of steel when a film of water flows over its surface. The experimental monitoring of corrosion dynamics in the flowing film was carried out using a laboratory pilot model, exploited in such a way as to obtain data necessary to identify some characteristic parameters of the mathematical model of this problem. The mathematical model of the case takes into account the transfer of oxygen through the liquid film flowing on the surface of the corroding plate where the chemical surface processes characteristic of corrosion occur (dissolution of Fe, oxidation of Fe²⁺ to Fe³⁺, formation of surface deposit, etc.). Experimental measurements were used to identify the parameters of the mathematical model, especially the reaction constant of the Fe dissolution rate and the surface oxidation yield of Fe²⁺ to Fe³⁺. Calculation of the correlation coefficients for the apparent constant surface reaction rate and process factors showed that they correlate strongly and non-linearly with the Reynolds number (Re) of the film flow, with the cumulative flow duration, and with the cumulative standby time of the experiments. Using the dynamics of the resistance to the transfer of oxygen through the rust film and the dynamics of its thickness resulting from the specific flow of rust deposition, the apparent oxygen diffusion coefficient through the rust film formed on the plate was expressed.