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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Medida da umidade do solo com sonda de neutrons

FALLEIROS, MARCOS de C. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:37:48Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:12Z (GMT). No. of bitstreams: 1 05379.pdf: 4344136 bytes, checksum: b82d5226e24d569d19317b8dc8a173fd (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
12

Medida da umidade do solo com sonda de neutrons

FALLEIROS, MARCOS de C. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:37:48Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:12Z (GMT). No. of bitstreams: 1 05379.pdf: 4344136 bytes, checksum: b82d5226e24d569d19317b8dc8a173fd (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
13

Experimental Evaluation of Cooling Effectiveness and Water Conservation in a Poultry House Using Flow Blurring<sup>®</sup> Atomizers

Rodriguez, Rafael M. 06 April 2017 (has links)
Increases in population as well as economic improvements in developing countries are generating a larger demand for animal protein products. Current animal growth processes inherently, require the use of water in many forms throughout the growth cycle. Water is the most important natural resource on earth to sustain life, and in many developing countries is a scarce resource that must be used wisely. Studies have revealed that poultry growth can take place with less water consumption, when compared with other sources of animal protein (e.g., cattle, pork). In this research, an evaporative Flow Blurring® cooling system was considered as an alternative method for cooling in a full scale poultry (e.g., chicken) farm located near Fayetteville, Arkansas, USA. Flow Blurring® is a very efficient pneumatic atomization process, currently used in evaporative cooling consumer products, chemistry instrumentation/analysis equipment, and in combustion investigations. In this dissertation, the Flow Blurring® cooling system was designed, manufactured, installed, and experimentally investigated. A custom control system (i.e., controls logic) was developed to run the sequence of actions required during the operation. Experimental results from the Flow Blurring® cooling system were compared to an existing Cool-Pad evaporative system the current standard in the poultry industry. The implementation of this new evaporative cooling system resulted in a reduction of approximately 78% in water consumption (10,443 gallons) used for cooling, while the Flow Blurring® cooling system and Cool-Pad systems were concurrently in operation. The Flow Blurring® cooling system maintained comparable and/or enhanced environmental conditions (i.e., temperature and humidity). Power consumption was higher by 13% when compared to the existing cooling system. The results demonstrate the potential application of a Flow Blurring® cooling system in the poultry agricultural field.
14

AC Impedance Spectroscopy Analysis of Improved Proton Exchange Membrane Fuel Cell Performance via Direct Inlet Humidity Control

Tan, Li 06 December 2010 (has links)
No description available.
15

Case Study on Residential Humidity Control at U.S. Coast Guard Bayamon Housing

Meneses, Ivan R. 21 November 2004 (has links)
The intention of this study is to investigate the main source of unacceptable humidity levels at the U.S. Coast Guard Housing located in Bayamon, Puerto Rico. The aim of this research is to use a systematic approach to resolve the humidity and mold issues by testing the least expensive solutions first. This study involves the recording of indoor air quality conditions for six months as an analysis tool to investigate current air conditions and to document how physical changes to the air conditioning units will affect the resulting air conditions. This research will investigate and implement different approaches geared to solving the high humidity issues. Some of the most relevant changes that will be tested are the installation of heat pipe technology, the addition of fresh air to existing air conditioning units to create positive pressure, and the review of the space load design of currently installed air conditioning units to determine if the units were over-designed. In addition, this study will verify the relationship between energy-saving thermostats and high humidity, determine any connection between roof leaks and high humidity indoors, and determine the estimated cost to the Coast Guard to implement the recommended changes.
16

A SEQUENTIAL APPROACH FOR ACHIEVING SEPARATE SENSIBLE AND LATENT COOLING

Jie Ma (11191899) 28 July 2021 (has links)
<p>Current air conditioning systems generally operate with a relatively fixed moisture removal capacity, and indoor humidity conditions are usually not actively controlled in most buildings. If we focus only on sensible heat removal, an air conditioning system could operate with a fairly high evaporating temperature, and consequently a high coefficient of performance (COP). However, to provide an acceptable level of dehumidification, air conditioners typically operate with a much lower evaporating temperature (and lower COP) to ensure that the air is cooled below its dew point to achieve dehumidification. The latent (moisture related) loads in a space typically only represent around 20-30% of the total load in many environments; however, the air conditioning system operates 100% of the time at a low COP to address this small fraction of the load. To address issues associated with inadequate dehumidification and high energy consumption of conventional air conditioning systems, the use of a separate sensible and latent cooling (SSLC) system can dramatically increase system COP and provide active humidity control. Most current SSLC approaches that are reported in the literature require the installation of multiple components or systems in addition to a conventional air conditioner to separately address the sensible and latent loads. This approach increases the overall system installation and maintenance costs and complicates the controller design. </p> <p>A sequential SSLC system is proposed and described in this work takes full advantage of readily available variable speed technology and utilizes independent speed control of both the compressor and evaporator fan, so that a single direct expansion (DX) air-conditioning (A/C) system can be operated in such a way to separately address the sensible and latent loads in a highly efficient manner. In this work, a numerical model of DX A/C system is developed and validated through experiential testing to predict the performance under varied equipment speeds and then used to investigate the energy saving potential with the implementation of the proposed sequential SSLC system. To realize the sequential SSLC system approach, various corresponding control strategies are proposed and explained in this work that minimizes energy consumption while provides active control over both space temperature and relative humidity. At the end of this document, the benefits of applying the SSLC system in a prototype residential building under different typical climate characteristics are demonstrated.</p>
17

Environment driven consumer EC model incorporating complexities of consumer body dynamics

Ali, S.M., Khan, B., Mokryani, Geev, Mehmood, C.A., Jawad, M., Farid, U. 18 February 2019 (has links)
Yes / Energy consumption (EC) of consumers primarily depends on comfort level (CL) affirmed by brain sensations of the central nervous system. Environmental parameters such as surroundings, relative humidity, air temperature, solar irradiance, air pressure, and cloud cover directly influence consumer body temperature that in return affect blood dynamics perturbing brain comfort sensations. This CL (either in summer, winter, autumn, or spring season) is a function of external environment and internal body variations that force a consumer toward EC. To develop a new concept of consumer's EC, first the authors described environment parameters in detail with relation to surroundings and EC. Considering this, they tabulated a generic relation of consumer's CL with EC and environment temperature. Second, to build an inter-related bond between the environmental effects on consumer body dynamics, they analysed theoretically and mathematically above mutual relations between medical and environmental sciences. Finally, they present their conceptual EC model based on a closed-loop feedback system. This model is a complex non-linear adaptive system with environmental and surrounding parameters as input to the system resulting in an optimised EC, considering consumer CL as a key parameter for the system.

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