Simulating effect of neonate body position on carbon dioxide tension in oxygen tent

Oxygen therapy is a common method of respiratory support, but its use involves the risk of carbon dioxide recycling and the development of hypercapnia in the patient.The aim of the study. Assess the carbon dioxide tension in the oxygen tent depending on the patient's body position in the experimental newborn Model.Materials and Methods. The study was performed on the phantom of the newborn. Influence of 3 patient positions at fresh mixture feed rate 2.5, 5, 7 and 10 l/min is evaluated. Monitoring of the carbon dioxide tension was carried out using Testo 480, measurements were carried out for 60 minutes.Results of the study. A clear relationship was established between the position of the newborn's body and the tension of carbon dioxide in the oxygen tent. The minimum tension of carbon dioxide is noted in the patient's position ≪on the back≪ at a fresh mixture feed rate of 7.5 l/minute and is 527 ± 64 ppm, and the maximum ‒ in the child's position ≪on the stomach≪ at the same oxygen-air mixture feed rate: 1180 ± 63 ppm.Conclusion. The position of the newborn baby's body is the main factor affecting the carbon dioxide stress in the oxygen tent.

Specification of the Properties and Effects of Additives and Admixtures on a Mixture Suitable for 3D Printing of Buildings

This article focuses on 3D printing of buildings using cement mortar-based material. Specific requirements are necessary for such a material; it therefore must have different properties compared to conventional cement mortar. These properties of a fresh mixture and the possibilities for their testing are described in more detail in the first part of the article. Specifically, these are pumpability, printability, buildability, and workability. In order to achieve these properties, it is necessary to add various additives and admixtures to the mixtures, in addition to the basic components such as water, sand, and cement. Scientists around the world are working to create an optimal mix. The second part of this article presents an overview of the most commonly used ingredients and their effect on the properties of the mixture.

EFFECT OF SUPERABSORBENT PARTICLE SIZE ON RHEOLOGY AND MECHANICAL PERFORMANCE OF CEMENT MORTARS

The risk of crack propagation and autogenous shrinkage pose a significant weakness for concrete structures and substantially limits its lifespan. To overbridge related issues, the smart superabsorbent polymers (SAP) can be utilized to mitigate autogenous shrinkage and promote self-healing ability. However, incorporation of highly swelling particles struggles with the workability of the fresh mixture and thus final mechanical performance. Within this paper, the effect of SAP particle size is studied and correlated with the results of flow table test to propose an optimal relationship between the amount of SAP dosage, water/cement ratio and mechanical properties in the hardened state. The reference cement mortar mixture is modified by 0.25, 0.5 and 0.75 wt.% admixture of different 3 grades of SAPs thus the fresh mixture workability, basic material properties, compressive and flexural strength parameters are determined. The obtained results provide guidelines for the efficient design of SAP modified cement mortars mixtures with desired functional properties.

Nutrient content and fermentation characteristics of ensiled Italian ryegrass and winter cereal mixtures for dairy cows

The interest in new alternative forages in Europe has increased in recent years. The nutritional composition and fermentation characteristics during different stages of ensiling were studied with Italian ryegrass (Lolium multiflorum Lam.) and winter cereal mixtures. The trial was carried out on a large-scale farm Galgamenti Agricultural Limited Company, Tura, Hungary. Two different forage mixes were studied: Mixture A (three types of Italian ryegrass 40% + two types of triticale 20%+ two types of oats 20%+ wheat 15%+ barley 5%) and Mixture B (three types of Italian ryegrass 55% + two types of winter oats 45%). Experimental field was 30.600 m 2 by the treatments, respectively. The two different forage mixes were sown on 11th September 2017 (Mixture A: 75 kg seed/ha; Mixture B: 75 kg seed/ha) with depth of 2-5 cm. Plant protection treatment was not applied during the growing season. Cutting was carried out in heading stage of triticale by hand at 10 cm stubble height. The fresh Mixture A (dry matter 189 g/kg; crude protein: 161 g/kg DM; NDF: 485 g/kg DM) and the fresh Mixture B (dry matter 195 g/kg; crude protein: 159 g/kg DM; NDF: 519 g/kg DM) were wilted to 28-32% DM (24h) without any movement on the windrow. The wilted forage was picked up by hand and chopped by a forage harvester (John Deere 7300) on concrete surface with theoretical chop length of 9 mm (weight: 800 kg). Wilted and chopped material of 510 g were packed by hand into a glass jars (0.00072 m3 volume, n=5, total no. of minisilos = 15). Five laboratory silos per mixtures were opened on 7, 14 and 90 days after ensiling. Dry matter (DM), crude protein (CP), crude fiber (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), ether extract (EE), ash, and total sugar of all treatments were determined. Additionally, pH and the concentration of ammonia-N, volatile fatty acids were measured in the ensiled mixtures. At the end of 90 days of ensiling in both mixture silages, there were significant differences (p<0.05) in all nutrient contents except for ADF in Mixture A and CP, ash and CF in Mixture B which was not affected by fermentation duration. Ensiling caused a significant decrease in pH (p<0.05), due to the production of lactic acid and succeeded to achieve lactic acid type fermentation. Values for ammonia-N, ethanol and acetic acid, butyric acid were all low. These results indicated that the fermentation quality of Italian ryegrass and winter cereal silages underwent rapid fermentation and were well-preserved.

Influence of mixture composition on fresh concrete workability for ballastless track slabs

There are several factors that affect the fresh concrete workability: water demand and composition of Portland cement, properties of fine and coarse aggregates, presence of superplasticizer and others admixtures, etc. Influence of quantity and fineness of ground quartz additives as well as polycarboxylate-based superplasticizer amount on workability of fresh concrete was studied in the paper. The properties of fresh mixture (slump) and hardened concrete (compressive strength at the age of 24 hours, 28 and 360 days) were estimated. Enhancing the fresh concrete workability using fine ground quartz sand was stated. Savings of superplasticizer per 1 m3 of slab concrete and 1 km of the ballastless track were calculated.

Application of concrete slurry waste in cement screeds

Sedimented concrete slurry waste (CSW), containing cement, mineral additives, fine fillers, admixtures and water, is currently a waste without an additional use and has to be fully landfilled. Current CSW management is very expensive and introduces number of environmental risks due to its high pH, exceeding 11.5. This paper deals with the application of two types of CSW as cement replacement in cement screed. The evaluation was carried out in terms of workability and basic mechanical performance of the obtained composites. The applied cement replacement was up to 10 wt.% due to the negative impact on the rheology of fresh mixtures. Reduced workability consequently caused higher content of air in the fresh mixture. It was reflected by lower values of bulk density in hardened state for both studied CSW. These aspects were the reasons of decreased mechanical performance by approximately 15% per 5 wt.% of replacement. Conducted experimental program declared significant limits of CSW application in cement based composites, however additional processing of CSW could significantly modify its properties.

Changes of Physicochemical composition of Moroccan bovine’s milk along the years

Milk production in Morocco has increased in recent years to meet local demand. For this reason, this work was carried out in order to study the evolution of the main factors of physicochemical variation of fresh mixture milk of the cow harvested in Moroccan farms and cooperatives, by comparing them with the results of research carried out in Morocco during the last century. 52 samples were taken to represent the different periods of the year. The results showed that the physicochemical properties studied were not significantly improved over the years. Thus, the protein content (3.05%) decreased concerning the fat content (3.57%) in recent decades. This change is mainly related to lactation, cow diet and climate change. Overall, these results could help further studies aimed at controlling the physicochemical properties of milk, taking into account the factors mentioned.

Thermodynamics of indirect water injection in internal combustion engines: Analysis of the fresh mixture cooling effect

Water injection is a well-known efficient way to improve the performance of internal combustion engines. Amazingly, most of previous studies have yet only assess this process in an experimental manner, depriving us of an understanding of its specific influence on different operating phases of the engine – density of the aspirated fresh mixture, work required by the compression stroke, and so on – but also of the possibility to predict its effects if set up on an existing engine. Thanks to a theoretical framework specifically developed, and similar to the one commonly used for the analysis of air conditioning systems, we start in this article to untangle in a theoretical manner the different consequences of water injection on internal combustion engines. This first study is specifically focused on the fresh mixture density increase, due to the vaporisation of liquid water in the intake manifold. Results show that in the best scenarios, we cannot expect to increase the amount of fuel finally aspirated into the cylinders by more than 10%. The methodology presented here can be of a precious help for the optimisation of such process if applied to existing or future engines.

Thermodynamics of indirect water injection in internal combustion engines: theoretical assessment of the fresh mixture cooling effect

Water injection is a well-known efficient way to improve the performance of internal combustion engines. Amazingly, most of previous studies have yet only assess this process in an experimental manner, depriving us of an understanding of its specific influence on different operating phases of the engine (density of the aspirated fresh mixture, work required by the compression stroke, and so on) but also of the possibility to predict its effects if set up on an existing engine. Thanks to a theoretical framework specifically developed, and similar to the one commonly used for the analysis of air conditioning systems, we start in this paper to untangle in a theoretical manner the different consequences of water injection on internal combustion engines.This first study is specifically focused on the fresh mixture density increase, due to the vaporisation of liquid water in the intake manifold. Results show that, in the best scenarios, we cannot expect to increase the amount of fuel finally aspirated into the cylinders by more than 10%. The methodology presented here, as well as the python software specifically developed, can be of a precious help for the optimisation of such process if applied to existing or future engines.