Characterization of thermal flow sensors for air flow measurements in transport containers

Abstract Air flow measurements inside containers for sensitive and perishable products effectively participate in improving transport processes. Results of such measurements allow taking preventive actions to maintain the desired temperature during transport trips. Consequently, we can optimize the quality of transported goods and reduce their losses. Thermal flow sensors are chosen for these measurements. This paper introduces an overall characterization of these sensors to prove their suitability for the intended objective. The characterization covers the air velocity range from 0 to 5 m/s, which is the expected range in the container. Results show that the characteristic curve is linear for the ultra low flow range and the minimum detectable air velocity is ca. 0.4 mm/s

Thermal study of a transport container

A thermal study of a container for international transport has been carried out in order to determine the temperature distributions. Several experimental conditions such as cooling modes, the onset of defrosting, the existence of cargo inside the container and two varying set points have been evaluated. It was observed that the difference between the temperature inside the container and the set point raised up to 30% of ambient temperature. Moreover, it was observed that the modulated cooling allowed to obtain a more homogeneous refrigeration. However, temperature differences up to 8 °C were observed under on–off control cooling

Flow Sensors and their Application to Convective Transport of Heat in Logistic Containers

Flow measurement has achieved huge strides in the last few decades. This phenomenon is a source that stimulates new applications. Performing an airflow measurement in logistic containers to maintain quality of sensitive products is one of these up-to-date applications. This thesis has two main objectives: First, to prove the suitability of thermal flow sensors for accurate airflow measurements. Second objective is to perform measurements and simulations in order to understand the convective transport inside reefer containers and improve the cooling system efficiency. On the sensor side, basic research studies were performed, including modeling, characterization, calibration, and integration in wireless measurement system. On the application side, several airflow field tests were conducted. Moreover, a simulation model was developed. Experimental results supported the simulation results, wherein both give a good understanding of the airflow and convective transport in the container

Space Station RT and E Utilization Study

Descriptive information on a set of 241 mission concepts was reviewed to establish preliminary Space Station outfitting needs for technology development missions. The missions studied covered the full range of in-space technology development activities envisioned for early Space Station operations and included both pressurized volume and attached payload requirements. Equipment needs were compared with outfitting plans for the life sciences and microgravity user communities, and a number of potential outfitting additions were identified. Outfitting implementation was addressed by selecting a strawman mission complement for each of seven technical themes, by organizing the missions into flight scenarios, and by assessing the associated outfitting buildup for planning impacts

Water, vapour and heat transport in concrete cells for storing radioactive waste

Water is collected from a drain situated at the centre of a concrete cell that stores radioactive waste at ‘El Cabril’, which is the low and intermediate level radioactive waste disposal facility of Spain. This indicates flow of water within the cell. 2D numerical models have been made in order to reproduce and understand the processes that take place inside the cell. Temperature and relative humidity measured by sensors in the cells and thermo-hydraulic parameters from laboratory test have been used. Results show that this phenomenon is caused by capillary rise from the phreatic level, evaporation and condensation within the cell produced by temperature gradients caused by seasonal temperature fluctuations outside. At the centre of the cell, flow of gas and convection also play a role. Three remedial actions have been studied that may avoid the leakage of water from the drain.Peer ReviewedPostprint (author's final draft

Team One Carbon Catcher Design Report

Overview The burning of fossil fuels largely contributes to the increase of CO2 in the atmosphere. The US Department of Transportation alone contributed almost 6 million metric tons of carbon dioxide emissions in 2018 (EIA). Due to this, this report proposes recycling captured CO2 into a base for cleaner burning fuel in order to reduce emissions from the transportation industry and many others, which has the potential to impact many areas. Extraction of atmospheric CO2 is possible through a membrane filtration system based on traditional nitrogen generation. The passive filtration system autonomously separates the CO2 from other air components, thereby reducing energy consumption. The system's working sensors and actuators utilize similar energy saving strategies, such as distributing cloud-computing services over multiple servers and mainframes to reduce computing power. The movement of air is directed by a scalable fan device, which is presented as a modular design to allow customization of fan parts to specific size and installation requirements. As an integrated device, Team 1’s Carbon Catcher operates with a high efficiency in order to maximize the commercial opportunity of converting captured CO2 into cleaner fuel while also reducing CO2 emissions and the greenhouse effect. Goal The goal of Team 1’s Carbon Catcher project proposal is to design a cost-effective, scalable, and modular atmospheric carbon dioxide removal system that is capable of being utilized in a range of urban environments and may fit a variety of different customer requirements or requests

The First United States Microgravity Laboratory

The United States Microgravity Laboratory (USML-1) is one part of a science and technology program that will open NASA's next great era of discovery and establish the United States' leadership in space. A key component in the preparation for this new age of exploration, the USML-1 will fly in orbit for extended periods, providing greater opportunities for research in materials science, fluid dynamics, biotechnology, and combustion science. The major components of the USML-1 are the Crystal Growth Furnace, the Surface Tension Driven Convection Experiment (STDCE) Apparatus, and the Drop Physics Module. Other components of USML-1 include Astroculture, Generic Bioprocessing Apparatus, Extended Duration Orbiter Medical Project, Protein Crystal Growth, Space Acceleration Measurement System, Solid Surface Combustion Experiment, Zeolite Crystal Growth and Spacelab Glovebox provided by the European Space Agency

Fruit Tree Responses to Water Stress: Automated Physiological Measurements and Rootstock Responses

New orchard plantings utilize trees grafted to dwarfing rootstocks planted close together to facilitate larger harvests. These dwarfing rootstocks have not been comprehensively studied for their ability to withstand drought. This is of special importance in the Intermountain West which has limited rainfall. Additionally, orchard growers face competition for water from a growing population and increased uncertainty in rainfall from climate change. My research examined the use of dendrometers, which measure changes in trunk diameter, and sap flow sensors, which measure how quickly sap moves, as methods to inform growers about tree water status. I also used a weighing lysimeter system to measure tree water use in four different rootstocks as they were subjected to drought. In a field study, I placed dendrometers and sap flow sensors in a high-density apple orchard. As the trees progressed through the season and put on fruit the responses from the sensors changed. By separating data from the sap flow sensors and dendrometers into seasons, their ability to predict tree water status improved. I found that overall dendrometers would be the best way to automate measurements of tree water status. In my first rootstock trial I examined responses of peach trees grown from seeds from an orchard maintained by Navajo farmers in South Western Utah, and a commercially available rootstock. I found that the Navajo peach trees put on more growth than the commercial trees despite drought, which suggests that they may be useful for rootstock development. In my second rootstock trial I examine the commercially available Krymsk® 5 and 6 series dwarfing cherry rootstocks for responses to drought. I found that the Krymsk® 6 rootstocks had higher rates of transpiration and used water faster than the Krymsk® 5 allowing them to put on growth quickly even during drought. Krymsk® 5 rootstocks have a lower percentage of their biomass in their roots which may have helped to conserve water

The effects of packing structure on the effective thermal conductivity of granular media: A grain scale investigation

Structural characteristics are considered to be the dominant factors in determining the effective properties of granular media, particularly in the scope of transport phenomena. Towards improved heat management, thermal transport in granular media requires an improved fundamental understanding. In this study, the effects of packing structure on heat transfer in granular media are evaluated at macro- and grain-scales. At the grain-scale, a gas-solid coupling heat transfer model is adapted into a discrete-element-method to simulate this transport phenomenon. The numerical framework is validated by experimental data obtained using a plane source technique, and the Smoluschowski effect of the gas phase is found to be captured by this extension. By considering packings of spherical SiO2 grains with an interstitial helium phase, vibration induced ordering in granular media is studied, using the simulation methods developed here, to investigate how disorder-to-order transitions of packing structure enhance effective thermal conductivity. Grain-scale thermal transport is shown to be influenced by the local neighbourhood configuration of individual grains. The formation of an ordered packing structure enhances both global and local thermal transport. This study provides a structure approach to explain transport phenomena, which can be applied in properties modification for granular media.Comment: 11 figures, 29 page