The effects of the depth of fertilization on losses of nitrogen and phosphorus and soil fertility in the red paddy soil of China

Nitrogen (N) and phosphorus (P) losses from agroecosystems are dominant nonpoint pollution. To minimize the losses of N and P, the optimal depth of fertilization was explored using a soil column study with the red paddy soil as the research objects. The losses of N and P were measured under five depths of fertilization (0, 5, 7.5, 10, and 12.5 cm) as well as no fertilization. The results showed that ammonia volatilization was significantly decreased with increasing fertilization depth within 0–10 cm, and there was no significant difference among the 10 cm, 12.5 cm, and no-fertilization treatments. Comparing with surface fertilization (0 cm), N and P losses by runoff could be reduced by 30.7–67.1% and 96.9–98.7% respectively by fertilization at 5–12.5 cm. In addition, deep fertilization (5–12.5 cm) did not increase N and P losses by leaching at the depth of 40 cm. Total N and P contents in the tillage layer of soil were increased by 5.1 to 22.8% and by −1.0 to 7.5%, respectively. Fertilization at 10cm depth has the potential to minimal environmental impact in the red paddy soil of south China, at this depth, NH3 volatilization was reduced by 95.1%, and N and P losses by runoff were reduced by 62.0% and 98.4%, respectively, compared with surface fertilization.

Weight Is More Accurate than Gestational Age When Estimating the Optimal Endotracheal Tube Depth in Neonates

Determining the optimal endotracheal tube (ETT) depth in neonates remains challenging for neonatologists. The guideline for optimal ETT depth is based on the patients’ weight or gestational age. However, there is a discrepancy in the suggested ETT depth between these two parameters. The aim of this retrospective study was to compare the recommended weight-based and age-based formulas for optimal ETT depth and obtain the optimal reference before intubation. Participants were assigned to group 1 if the recommended ETT insertion depth based on weight was concordant with the recommended depth based on gestational age, and to group 2 if the weight and age-based depth recommendations were discordant. After exclusion, 180 patients were included in the analysis. Results indicated that the predicted ETT depth suggested by age required more adjustment than by weight (p < 0.05). Furthermore, the required adjustment in the weight-based formula was smaller than the age-based formula (p < 0.05). Multivariate linear regression analysis revealed that weight was the key factor affecting the optimal depth (p < 0.001). These results imply that when there is a discrepancy in ETT depth between the weight-based and age-based recommendation, the weight-based one will be more accurate than the age-based one.

Optimal depth selection of composite tubular-floor trusses based on cost estimation

The significance of this study initiates from the need to produce a selection guidance on the span range, span-to-depth ratio and scheme of the composite floor truss system to provide optimum performance and cost effectiveness for a particular application area. With this objective a parametric study was designed, based on three parallel chord trusses (Pratt, Howe, and Warren) using Rectangular Hollow Structural Shapes, a constant panel size of 2.5 m, four composite floor European-profiles and a range of load intensities. Hence, the span-to-depth ratios, RS/D, and dead-to-live load ratios, RDL/LL, were ranged from 3 to 27 and 0.84 to 3.22, respectively, for each truss type. The optimization was performed by using the design results of RFEM (2018) software for approximately 675 composite floor trusses with the objective of selecting optimal depth for each truss model. In addition, this paper attempts to introduce a cost function by considering the material, fabrication and painting costs and comparative figures allowing the design to be tailored with a focus on cost reduction. Accordingly, for all truss types, span-to-depth ratio of 9 to 12 with a span range of 7 to 23 m provides the most cost effective solution. Structural steel and the welding process are the two parameters that are found to have the highest impact on total cost.

STUDY ON EFFICACY OF ULTRASOUND AND FOB IN CONFIRMING THE PLACEMENT OF LARYNGEAL MASK AIRWAY

Ultrasound is a safe and non invasive technique for assessing the airway . In this observational study, 60 patients belonging to ASAClasses I and II scheduled for elective general surgery without any airway abnormality were included. Squared wave of capnogramTransverse neck ultrasound was performed using linear probe (8- 13Hz) started from hyoid bone (hyperechoic supercial inverted Ushaped linear structure)probe moved caudally with slight cephalad angle visualization of vocal cord & arytenoids. The Ultrasound arytenoid grade had a signicant correlation with LMA rotation grade.The incidence of LMAMalposition by ultrasound was found to be 80% .With regard to the test performance ,US was found to have a sensitivity of 92%,with a positive predictive value of 94% to detect the LMA rotation of any number of degrees. The specicity was 62% with a negative predictive value of 55%. FOB Examination is the gold standard tool for conrmation of the correct placement of LMA. ,we evaluated USG as a tool to conrm the placement comparing with the FOB examinationThe FOB examination is invasive & interrupts the ventilation during procedure. It cannot be done frequently intra-operatively compromising ventilation. These problems can be overcome by using ultrasound.USG detects the rotation of LMAeven if it is positioned at optimal depth thereby predicting the chance of dislodgement during the course of surgery.

Maximizing avertable doses with a minimum amount of waste for remediation of land areas around typical single family houses after radioactive fallout based on Monte Carlo simulations

The uncontrolled release of long-lived radioactive substances from nuclear accidents can contaminate inhabited land areas. The removal of topsoil is an important method for reducing future radiation exposure but can also generate a large amount of waste that needs safe disposal. To the best of our knowledge, previous studies have determined the optimal depth of topsoil removal but not the size of the area designated for this measure. For this purpose, this study performed Monte Carlo simulations of hypothetical 137Cs surface contamination on various ground areas in a typical northern European suburban area. The goal was to study the size of the areas needed and amount of waste generated to achieve a certain relative and absolute dose reduction. The results showed that removing the topsoil from areas larger than 3000 m2 around the houses in the study neighbourhood results in only marginal reduction in radiation exposure. If, on average, 5 cm of topsoil is removed over 3000 m2, then 150 m3 of waste would be generated. However, in this scenario adjacent properties benefit from each other’s decontamination, leading to a smaller amount of waste for a given reduction in future radiation exposure per inhabitant of these dwellings. Additionally, it was shown that topsoil removal over limited areas has a higher impact on the absolute dose reduction at an observation point inside or outside the houses with higher initial dose.

Feasibility Demonstration of the Effective Design of the Opener Group of the Seeder for Winter Wheat in Arid Conditions

The article is devoted to improving the winter wheat seeding technology. Choosing the rational design of the opener group enables the placement of crop seeds in a deeper moisty soil layer for their rapid germination with the formation of a surface relief from furrows. Seeds are placed into furrows at the optimal depth 4-5 cm and furrow slices are formed by the soil thrown out of the furrow by chisel-shaped openers and compacted by individual rollers for each opener. That solves the problem of insufficient soil moisture in arid regions.

OPTIMIZATION OF PARAMETERS OF WORKING BODIES OF MACHINES FOR SUGAR BEET PRODUCTION

Existing technologies and modern technical means do not always provide the required quality of technological processes for growing sugar beets. Increasing requirements necessitate continuous improvement of existing and creation of new high-performance machines and units to ensure high-quality production technologies of sugar beet crops. Improved technological processes for the production of sugar beet crops are described in the article. Such technological processes include: loosening the compacted topsoil and destruction of the soil crust before the emergence of sugar beet shoots, loosening the soil after emergence, feeding sugar beets with increased soil hardness and low moisture content, inter-row soil cultivation with hilling plants in lines. As a result of research of technologies for inter-row processing of sugar beets in the system of crop care, the following ratio was established: the optimal depth and width of the strips for cutting the top layer of the soil, depending on the depth of placement of the sown seeds; the distance between the ribs of the roller, depending on the depth of cutting the soil; the maximum depth of soil loosening in the row zone and the row spacing zone, depending on the depth of sowing seeds and the placement of the root system of beets; the required depth of soil loosening in the aisles, depending on the specified optimal depth of application of mineral fertilizers in the aisles; the required distance from the conditional centerline of the beet rows to the zone of mineral fertilization in the aisles, etc. The use of optimized technological processes makes it possible to create the necessary conditions for the growth and development of sugar beet plants on heavy-textured soils and after a significant amount of precipitation and an increase in soil density. In addition, the proposed innovative technologies ensure the preservation and even increase of soil moisture, reduction of sparseness and contamination of crops, as well as losses and damage to sugar beet roots during harvesting. The research results can be used to improve and optimize zonal technologies and technical means for growing sugar beets in conditions of high density and insufficient soil moisture, as well as in the educational process in the preparation of future specialists from agricultural engineering for scientific project activities.