New Insight into Organomineral Interactions in Soils. The Impact of Clay-Size Peat-Derived Organic Species on the Structure and the Strength of Soil Silt Aggregates

Data Availability Statement: The data presented in this study are available on request from the corresponding author. The data are not publicly available due to requiring specific software to view the data files. Most of the data are presented within this publication in the figures.Knowledge of the effects of different organic species on soil structure and strength is gained mostly from experiments on natural soils amended with organic substances of various particle sizes, pH, ionic composition, and inorganic impurities. It greatly diversifies the experimental results and shadows individual effects of organic amendments. Therefore, to look for a clearer view, we examined the impact of HCl-washed clay-size organic species: peat, humic acids, residue after humic acid extraction, and two biochars, all derived from the same peat and having similar particles, on the structure and strength of artificial soil silt aggregates using mercury intrusion porosimetry, bulk density measurements, SEM, and uniaxial compression. Bulk density increased due to humic acid addition and decreased for the other amendments. The total pore volumes behaved oppositely. All organic substances except humic acid decreased the pore surface fractal dimension, indicating a smoothening of the pore surface. Humic acid appeared to occupy mostly the spaces between the silt grains skeleton, while the other species were also located upon silt grains. The latter effect was most evident for 600 °C heated biochar. Humic acid, peat, and the residue after humic acid extraction improved mechanical stability, whereas both biochars weakened the aggregates, which means that bulk density plays a smaller role in the mechanical stability of granular materials, as it is usually considered. A new equation relating maximum stress and the amount of the organic additives was proposed.Funded in part by the National Science Centre, Poland within an Opus 15 Project 2018/29/B/ST10/01592 Effect of minerals and different forms of organic carbon on structure, porosity and mechanical and water stability of soil aggregates—model studies. The full APC waiver for this paper was granted and approved by the editorial office of “Agriculture” MDPI Journal

Impact of process engineering factors on stabilization of screw joint

The stabilization of screw joint and influence of factors protecting against loosening of the joint have been discussed in the present article. The results of experimental examinations associated with the impact of the type of protective coat on threaded section and lubrication on the value of tightening torque have been also presented

Road safety in bus transport

W artykule przedstawiono problemy bezpieczeństwa w transporcie autobusowym w małej firmie przewozu osób oraz przykładową analizę wybranego zagrożenia pracy kierowcy zgodnie z wymaganiami normy PN-N-18002:2011. Zaproponowano wprowadzenie usprawnień infrastruktury drogowej mogące wpłynąć na poprawę bezpieczeństwa drogowego.The paper presents the problems of safety of bus transport in the small business people and a sample analysis of selected hazards for the driver in accordance with the requirements of PN-N-18002:2011. Propose the introduction of no-improvement of road infrastructure that could improve road safety