Hydro-Mechanics Coupling on Rammed Earth Material: Drying Experiment at Structural Scale

Rammed earth structures are very sensitive to hydric conditions. Experimental studies have been undertaken to understand the link between liquid water transfer and mechanical behavior at structural scale. This study was done on a prismatic rammed earth sample of 15cm x 15cm x 45cm, structured as a wall element with several layers. Samples were subjected to one dimensional drying in an indoor environment. Humidity and temperature sensors were placed on each layer inside the sample. The kinetic of drying was monitored by continuous weighing the sample and humidity measurement at a regular interval. Results of water content evolution suggest that samples dry in two stages; the first stage is associated with relatively high evaporation flux of 13.88 g m-2h-1 while the second stage has very low flux of moisture evaporation. Unconfined compressive strength was performed in drying samples after 0, 2, 6 and 8 weeks of drying. In parallel, digital image correlation was used to determine the stiffness of samples. Results show an increase in compressive strength by the rate of 98 kPa per week in the first two weeks, then this rate reduces to 23 KPa per weeks after 8 weeks. These experimental results will allow to enhance the 3D hydro mechanical numerical model developed in the laboratory.

Coal Moisture Variations in Response to Rainfall Events in Mine and Coal-Fired Power Plant Stockpiles—Part 2: Evaporation

Additional moisture added in coal stockpiles due to rain and other climatic processes causes a significant problem worldwide, which leads to not only decrease in the heating value of the coal but also creates an extra efficiency penalty. Therefore, it is important to make some predictions for control of coal moisture within stockpiles after the rainfall. When the rain falls on the stockpile, it either runs off the surface or infiltrates the stockpile. The infiltrated water may evaporate from the surface, drain or stay within the stockpile. The aims of this study (parts 1 and 2) are to describe and compare the changes in coal moisture content following rainfall events. The mechanisms of runoff, infiltration and drainage after rainfall were described in the first paper of this series. In part 2 the influence of coal particle size and ambient conditions on the rate and depth of moisture evaporation within the stockpile is investigated. The laboratory experiments showed cyclic events of adsorbing moisture overnight and desorbing this moisture during the day as part of the coal surface evaporation process. The rate of evaporation from the surface of the fine coal stockpile was faster than the coarse stockpile; however, the coarse stockpile experienced a more efficient evaporation process because of its porous structure. Fine coal beds experienced evaporation only near the surface, while the maximum influencing layer of evaporation is a depth of 0.4 cm below the surface in coarse coal beds.

Comparison of Properties of 3D-Printed Mortar in Air vs. Underwater

Research and technological advancements in 3D concrete printing (3DCP) have led to the idea of applying it to offshore construction. The effect of gravity is reduced underwater, which can have a positive effect on 3DCP. For basic verification of this idea, this study printed and additively manufactured specimens with the same mortar mixture in air and underwater and evaluated properties in the fresh state and the hardened state. The mechanical properties were evaluated using the specimens produced by direct casting to the mold and specimens produced by extracting from the additive part through coring and cutting. The results of the experiment show that underwater 3D printing required a greater amount of printing output than in-air 3D printing for a good print quality, and buildability was improved underwater compared to that in air. In the case of the specimen layered underwater, the density and compressive strength decreased compared to the specimen layered in air. Because there are almost no effects of moisture evaporation and bleeding in water, the interlayer bond strength of the specimen printed underwater was somewhat larger than that printed in air, while there was no effect of the deposition time interval underwater.

Evolución temporal de humedales de la región ayacucho, mediante imágenes modis periodo 2002-2013

La presente investigación responde a la necesidad de caracterizar la evolución temporal de los humedales mediante imágenes satelitales, su procesamiento, análisis, interpretación y discusión, pues los cambios climáticos hacen necesario tener en cuenta que son ecosistemas importantes de gran interés por las diferentes funciones que realizan. Las imágenes satelitales del satélite TERRA del sensor AQUA, fueron procesadas con el software ENVI y se determinó el parámetro del Índice de Vegetación de Diferencia Normalizada (NDVI), más el uso del Google Earth nos permitió a grandes rasgos discriminar entre zonas de vegetación, suelo desnudo, agua y la variación en el tiempo de los Humedales de la Región de Ayacucho. La teledetección nos ofrece grandes progresos en el conocimiento de la naturaleza, aunque es necesario un mayor rigor científico en la interpretación de los resultados y tener como objetivo eliminar los efectos ocasionados por la variabilidad en las condiciones de captación, distorsión provocada por la atmósfera, y la influencia de parámetros radiométricos geométricos tales como la radiancia, reflectancia, emisividad, posición del Sol, pendiente, y altitud. Por lo cual esperamos que contribuya al conocimiento de datos importantes quedando pendiente estimar otros parámetros como la humedad de suelos, evaporación, etc. a través de la cual se precisará y reorientar la tecnología propuesta. images, processing, analysis, interpretation and discussion, as the climate changes make it necessary to consider that are important ecosystems of great interest in the different functions performed. Satellite images of the TERRA satellite AQUA sensor were processed with ENVI software and parameters Index Normalized Difference Vegetation (NDVI) was determined, plus the use of Google Earth allowed us to broadly discriminate between areas of vegetation, soil nude, water and variation in time of Wetlands in the region of Ayacucho. Remote sensing offers great progress in the knowledge of nature, although a greater scientific rigor in the interpretation of the results is necessary and aim to eliminate the effects caused by the variability in the conditions of recruitment, distortion caused by the atmosphere, and the influence of geometric radiometric parameters such as radiance, reflectance, emissivity, position of the Sun, slope, and altitude. So we hope to contribute to the knowledge of important data pending estimate other parameters such as soil moisture, evaporation, etc. through which shall specify and redirect the proposed technology.

Frying Conditions, Methyl Cellulose, and K-Carrageenan Edible Coatings: Useful Strategies to Reduce Oil Uptake in Fried Mushrooms

Despite being widely consumed and appreciated, fried food has the unhealthy characteristic of high final oil content. Therefore, alternatives to reduce the oil uptake of fried products are being researched. The aim of this study was to investigate the effect of 0.5% methyl cellulose and 0.5% kappa-carrageenan edible films, as well as different frying procedure parameters, such as oil temperatures (from 150 to 180 °C), and thickness of slices (from 2 to 6 mm) on the oil uptake of whole fried mushrooms and their parts. The results showed a lower final oil content when lower frying temperature and thicker slices are applied. Hydrocolloid suspensions of methyl cellulose and kappa-carrageenan, used as edible coatings, were effective at reducing moisture evaporation and, consequently, oil uptake independently of the hydrocolloid temperature. A reduction of 10–22% in the final oil content was achieved. Adjusting the frying parameters and the use of methyl cellulose or kappa-carrageenan as an edible coating were useful strategies to reduce the oil uptake in fried products.

Influence of low temperatures on heat balance in easily assembled premises of different types

The purpose of this work was to analyze the thermal balance of easily assembled premises of different types and sizes during the periods of low average daily temperatures. The research was conducted during the winter period of 2020–2021 in the Kyiv region. The used material was easily assembled premises of different types and sizes: easily assembled ones without insulation elements; with elements of warming and premises with deep-litter. In each of the studied premises were kept 400 dairy cows. The studies were performed during two periods: the first period had ambient temperatures from -10 to -14.9 °C and the second one from -15.0 °C and below. In our studies, the average daily temperature (during the ambient temperature from -10 to 14.9 °C) in easily assembled premises with the use of insulation elements was 6.20 and 5.31 °C higher than in premises without insulation and deep-litter. A similar trend was observed during the period of lowering the ambient temperature up to 15 °C and below. Thus, the advantage of the premises without insulation constituted 6.28 °C, and of the premises with deep-litter per 5.84 °C, respectively. It was found that keeping in easy-to-assemble premises with insulation elements, the consumption of free thermal energy from the whole herd during the experimental periods was lower compared to the keeping in a boxing cowshed and a cowshed with deep litter. This is due to the smaller range of fluctuations in the average daily temperature in a room with insulation elements. A similar trend was observed for energy consumption through enclosing structures and for moisture evaporation and, accordingly, total heat consumption. In general, heat deficiency was observed during the keeping of cows in the investigated premises of easily assembled type at negative temperatures (-10–14.9 and -15 °С and above). Accordingly, the thermal balance of the premises was negative. The highest values of heat balance among easily assembled premises in both research periods were observed for keeping in rooms that used insulation elements.

Influence of technological modes on changes in the composition of beet pulp during its processing at the Borinsky sugar plant

The description of the technological scheme of the granulation site at the Borinsky sugar plant is given, with an analysis of the work of the main types of technological equipment to identify problem areas of production. It is established that the use of such a promising press as the one of the Babbinni company allows you to get pulp with a humidity of 68-76 %. To dry it in a drum dryer to a humidity of 11–13%, 170 m3 of natural gas is consumed per 1 ton of pulp. The technological process of obtaining granulated beet pulp includes pressing the initial beet pulp with an initial humidity of 85–90% to a humidity of 68–76 %; drying the pressed pulp with a heat carrier at a temperature of 110–140 °C for 90–120 minutes to a final humidity of 11–13 %; cleaning pellets from metal-magnetic impurities; granulating the pulp (the diameter of the pellets is 10 mm); cooling pellets to a temperature of 30–35 °C; fractionation of pellets into large and small fractions; weighing and shipping granulated beet pulp to the warehouse of finished products. The technological modes influence analysis of beet pulp pressing, drying and granulating processes at the Borinsky sugar plant showed the need to introduce a second stage of pressing to further reduce the moisture content in the pressed pulp. Obtaining pressed pulp with a lower moisture content will significantly reduce the energy consumption for moisture evaporation in the drum dryer. Reducing the duration of the heat drying process of pressed beet pulp in a drum dryer will significantly increase the nutritional value of the granulated beet pulp produced.

Experimental investigation of the performance of a solar dryer integrated with solid desiccant coloums using water based solar collector for medicinal herb

This study is concerned with the analyses of performance on a solar dryer integrated with solid desiccant coloums using water based solar collector. The dryer consists of a solar water collector, two solid desiccant coloums, a water storage tank, two heat exchangers, an air heater, and a drying chamber. The dryer decreased the <em>Centella asiatica</em> L moisture content from 88.3% (wb) to 15.9% (wb) within 12 hours, with an average temperature and relative humidity of 45.4°C and 25.8%, respectively. The rate of moisture evaporation and the specific moisture evaporation rate were in the range of 0.001-1.762kg/h and 0.02-0.482 kg/kWh, with 0.594kg/h and 0.169kg/kWh in average values, respectively. The dryer efficiency was in the range of 0.62%-30.4%, with 15.4% in average value. The energy required for moisture evaporation and total energy input to the dryer were in the range of 26.9-1132.2W and 3638.0-4329.7W, with 601.8 W and 3967.4 W in average values, respectively. The efficiency of collector and the heat exchanger effectiveness were in the range of 38.1-50.5% and 65.1-79.7%, with 45.0% and 73.0% in average values, respectively. The result shows that the dryer is suitable for drying <em>Centella asiatica </em>L, this is due to the low temperature of drying air and high moisture evaporation rate.

EXPERIMENTAL INVESTIGATION OF CYLINDRICAL FOOD PRODUCT DURING FORCED CONVECTION COOLING

The objective of this work is to study the transient heat transfer behavior during precooling of cylindrical food product at different air flow rates. Temperature measurement is carried out at the center of the specimen at different air flow rates (3.8, 4.0, 4.2 & 4.5 m/s). These temperature distributions are plotted with time. The terms of Fourier equation were evaluated and thermal diffusivity was plotted against the temperature variation during cooling of the cylindrical food product.Surface film conductance values is also calculated in present work, at different air flow rates. These values are effective values, which included the additional cooling effect due to moisture evaporation from the exposed product surface. Variation of Reynolds number and Nusselt number is also plotted with different air velocities and it is found that more favorable results of thermal conductivity and thermal diffusivity is obtain at 3.8 m/s. Which ultimately saves energy and provide optimum cooling for the specimen at the given air velocity.