No description available.

Human performance and health are one of the most relevant topics in modern society. Especially at young ages, when academic performance is indispensable. Thus, as the human being spends most of its lifetime inside a building, thermal comfort has become an essential aspect of a room. The aim of the present research is to measure and evaluate the main thermal comfort parameters such as CO2 levels, relative humidity and indoor temperature so the variation in them can be seen in the study rooms of the library of the University of Gävle as there is student use. For it, Rotroninc Measurement Solutions CL11 sensors and a Testo hot wire probe sensor have been used, as well as IDA ICE software simulations for the result validation. From the research, has been seen that even though the VAV air renewal system works as it should, the CO2 level rises up to 1000 ppm, which is not recommended by different thermal comfort ruling institutions. This way, a modification to the ventilation system control is recommended, changing it from temperature control to CO2 level and temperature control. Moreover, it is seen that during the non-opening hours of the library the ventilation systems are disconnected, generating an important energy-saving without altering the thermal comfort of the rooms at the beginning of the day.

Ionic polymer-metal composites (IPMCs) are widely studied for their potential as electromechanical sensors and actuators. Bending of the IMPC depends on internal ion motion under an electric potential, and the addition of an ionic liquid and ionic self-assembled multilayer (ISAM) conductive network composite (CNC) strongly enhances bending and improves lifetime. Ion conducting polyelectrolytes poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS) and Nafion® were incorporated into an ISAM CNC film with poly(allylamine hydrochloride) (PAH) and anionic gold nanoparticles actuators to further improve bending. CNC films were optimized for bending through pH adjustments in PAH and adding NaCl to the PAMPS and Nafion® solutions. PAMPS-containing actuators showed larger and faster bending than those containing Nafion® in the CNC. The IPMC actuator was also evaluated for its potential as a humidity sensor based on its relative humidity (RH) dependent steady-state current. The detection range is at least 10-80%RH, with 5%RH increment differentiation and likely better resolution. Effects of CNC presence and thickness were studied, in conjunction with ionic liquid at a range of RH values. A thin CNC (pH 4 PAH) produced the greatest current differentiation between RH values. The current's response speed to a large RH decrease was approximately 4 times faster than that of a fast commercial digital hygrometer. Additionally, the presence of a CNC and ionic liquid improved the current response time. These results indicate that an IPMC based humidity sensor using a CNC and ionic liquid is very promising and merits further study. / Master of Science

Several techniques for measuring humidity are presented. The goal of the study is to use the electrostatic self-assembled monolayer synthesis process to fabricate a Fabry-Parot Cavity based optical fiber humidity sensor. The sensing scheme bases on the refractive index change with relative humidity of the film applied to the end of optical fiber. That is, the change in reflected optical power indicates certain humidity. To achieve this, some chemicals induce on specific coating materials were applied at the end of optical fiber. In this thesis, experimental results are given to prove that the humidity sensor has high sensitive and fast response time. Furthermore, we investigate the potential for the use of human breathing monitoring and air flow rate detection. Results from preliminary tests of each are given. / Master of Science

Moisture from concrete has been estimated to be responsible for over $1 billion annually from damages in floor coverings. To prevent damages, flooring manufacturers require installers to test concrete moisture levels to determine if the concrete has dried sufficiently to receive flooring or covering. Two of the main tests used in the United States to determine concrete moisture levels are moisture vapor emissions rate (MVER) tests and relative humidity (RH) tests. Changes in ambient temperature can affect the results of both RH and MVER tests. The goal of this study was to investigate the effects of ambient temperature changes on the RH of concrete, and compare the sensitivity of RH measurements to the results of MVER tests at the same ambient temperature. The RH of concrete was measured at 20%, 40%, 60%, and 80% of depth in each sample and tracked over a period of 24 days to develop drying curves at each depth, and drying profiles of each sample. The changes in concrete RH due to a change in ambient temperature were predicted using the psychrometric process and a model developed during this study. Due to size constraints on the concrete samples, ASTM 1869 had to be altered during the MVER tests. Typical RH change in the concrete samples was under 4% RH after either an increase or decrease in an ambient temperature of 5.5°C (10°F). The psychrometric process predicted that the concrete RH would change between 20% - 40% RH after the ambient temperature changed by 5.5°C. Psychrometric properties were not able to full describe the behavior of air in concrete pores so a new model was created to better predict the change in concrete RH after a change in ambient temperature. The developed model was able to predict concrete RH change within 5% error over the range of tested temperatures. / Master of Science

Cage studies were performed to determine if the current thresholds for stink bugs in soybean (one bug per 0.3 row m) need to be adjusted based on current soybean production practices and species present. Several soybean development stages were infested by two native stink bug species for three weeks using small cages in a field of double crop soybean at sites in Virginia, Maryland, and Delaware during 2007-2009. Large field cages were infested by an introduced species for two weeks in 2010-2011. Results showed that Euschistus servus Say and Acrosternum hilare Say adults or nymphs did not cause different levels of injury to soybean seed quality or effects on yield. Both A. hilare and the introduced Halyomorpha halys Stål injured soybean seed in a similar fashion at threshold-level densities. Full flowering R2 stage soybean were least affected by stink bug feeding, and full pod and beginning seed R4-R5 stage soybean were slightly more sensitive to injury than R6 although not at the Maryland 2011 site. Several sites had increased seed injury and decreased yield at threshold density populations. Finally, visual observations of stink bug vertical distribution inside soybean canopies were taken several times per day and compared with ambient and within-canopy temperature and relative humidity. Results indicated that these conditions did not influence the percentage of stink bugs below the top 38 cm sweep net intercept zone. In both years of observations, between 15 and 20% of stink bugs were observed below the 38 cm sweep net zone. / Master of Science in Life Sciences

Humans’ ability to combat heat stress through sweat-based evaporative cooling is modulated by air temperature and humidity, rendering human health highly sensitive to humid heat extremes. While the field of climate science has studied extreme dry bulb temperatures for decades, exploration of the physical drivers producing extreme humid heat is nascent in comparison. Two major areas of development for the evolving field are: 1) improving understanding of the local drivers of extreme humid heat, and 2) collating a set of universal physical mechanisms which generate humid heat extremes across the planet. The four chapters of this dissertation together advance each of these goals. Chapter 1 relates the occurrence of extreme humid heat in the Persian Gulf and South Asia to two related modes of intraseasonal climate variability, namely the Madden–Julian oscillation (MJO) and the boreal summer intraseasonal oscillation (BSISO). Wet bulb temperatures (Tw) sufficiently high to impact human health are found to be almost twice as likely during certain oscillation phases than in others. Humid heat anomalies in each region are driven by distinct local circulation patterns and variations in moisture. Chapter 2 evaluates the influence of monsoon onset and subseasonal precipitation variability on the occurrence of extreme Tw across South Asia. Extreme Tw events often occur on rainy days during the monsoon season. However, the influence of precipitation on Tw varies with the background specific humidity climatology. In climatologically drier areas, positive Tw anomalies tend to occur when precipitation increases due to either early onset or wet spells during the monsoon. In contrast, in climatologically humid areas, positive Tw anomalies occur during periods of suppressed precipitation, including delayed onset and dry spells during the monsoon. Chapter 3 analyzes the dynamics of the record-breaking extreme heat event in Rio de Janeiro in November 2023. The heatwave was associated with persistent atmospheric blocking, potentially linked to developing El Niño conditions. Temperatures were intensified by declining soil moisture and elevated local sea surface temperatures, and the event was finally terminated due to the onset of precipitation. This chapter also evaluates the influence of climate change on the frequency of heat extremes, finding a significant increase in the frequency of high heat days throughout Brazil over the past four decades. Further, the frequency of spring heat extremes is expected to increase in the future, though highly dependent upon our future emissions pathway. Chapter 4 explores the combinations of temperature and humidity contributing to humid heat experienced across the globe. In addition to using traditional metrics, this chapter derives a novel variable named “stickiness,” which quantifies the relative contributions of temperature and specific humidity to a given Tw. Consistent across metrics, high magnitudes of Tw tend to occur in the presence of anomalously high moisture, with temperature anomalies of secondary importance. Nonetheless, there is a broad range of stickiness observed for a given Tw across moderate-to-high Tw thresholds relevant to socioeconomic impacts.

The aim in this project is to find a design space for a condenser type bushing given by HitachiEnergy. The design space shows which combinations of air and silicon-rubber (SiR) conductivity remain under a specified electric field strength value. This range of value represents how humidity affects air and SiR conductivity. Hitachi energy provided two different models, one with foils and one without foils. The design space for these models consists of how humidity affects the conductivity of both air and SiR. The values of air conductivity are gathered from different studies with different air humidity and external effects that affect the conductivity such as high aerosol concentration and high radon concentration. The values used for simulation will be approximated because of the different external effects and will range from 10^(−12)–10^(−13) S/m for humid conditions, 10^(−14) S/m for average humidity conditions and 10^(−15)–10^(−16) S/m for dry conditions. The range of SiR conductivity and the correlated weather conditions was given by Hitachi Energy and range from 10^(−11)–10^(−15) S/m where 10^(−11) S/m is for humid conditions, 10^(−12)–10^(−14) S/m for average humidity conditions and 10^(−15) S/m for dry conditions. For each of these combinations of conductivity the maximum electric field strength is calculated using COMSOL Multiphysics and compared to the threshold value of 2 kV/mm. Using these parameters the maximum electric field strength on the sheds of the bushing was calculated using COMSOL Multiphysics for all combinations of SiR and air conductivity. The results shows a pattern for both models. SiR conductivity must be higher or equal to the air conductivity to be below the threshold of 2 kV/mm.

Prior research has shown that indoor air quality (IAQ) impacts cognitive performance. At Cal Poly, many older buildings are unable to maintain appropriate IAQ because of their outdated ventilation systems and the increasing number of students in the rooms. This work analyzes the IAQ of different buildings at Cal Poly, with a focus on Building 20. Carbon dioxide, temperature, and relative humidity inside classrooms are collected using an integrated circuit sensor and a microcontroller. A total of 38 hours of data was collected, with 22 of those hours in Building 20 specifically. We find that unlike temperature and relative humidity, CO2 levels routinely exceed 1,000 ppm—a concentration that hinders cognitive function. A questionnaire distributed to Cal Poly students suggests that while students can recognize poor IAQ in classrooms, they erroneously attribute these poor conditions to temperature and humidity instead of CO2. This data is then used to propose a system which can collect long-term data based on optimal placement, storage, and power requirements.

Condizioni meteorologiche e clima influenzano fortemente il settore delle produzioni animali. Lo stress da caldo determina una significativa riduzione dell'attività metabolica, della produzione, della capacità riproduttiva e una maggiore predisposizione alle malattie. Nel contesto biologico, la temperatura dell’aria è sicuramente considerata il principale fattore di stress, tuttavia, un’elevata umidità peggiora l'effetto della temperatura riducendo le perdite di calore per evaporazione e ostacolando quindi l’eliminazione del calore in eccesso. Scopi principali della ricerca sono stati la caratterizzazione dell’area del Mediterraneo in termini di Temperature Humidity Index (THI) e stabilire le relazioni tra stagione/THI e mortalità nella bovina da latte allevata in un’area geografica Italiana altamente vocata per questo tipo di allevamento. I risultati suggeriscono che, allevatori e politici che operano nell’area Mediterranea, dovrebbero tenere nella dovuta considerazione variabilità e scenari del THI nella pianificazione degli investimenti nel settore delle produzioni animali. Conoscere in anticipo il verificarsi di condizioni climatiche avverse permetterebbe agli allevatori di metter in atto misure di contrasto sugli effetti negativi delle condizioni climatiche. Inoltre, dovrebbero venire sviluppate misure di adattamento appropriate per contesti specifici in termini di cultura, società, o sistemi politici, che possano contribuire alla sostenibilità ambientale, nonché allo sviluppo economico e alla lotta alla povertà. / Weather and climate strongly influence the field of animal production. Heat stress causes a significant reduction in metabolic activity, production, reproductive capacity, and increases susceptibility to diseases. In the biological context, the air temperature is definitely considered the main factor of stress, however, high humidity worsens the effect of temperature by reducing the evaporation heat loss and thus preventing the removal of excess heat. The main purposes of the research were the characterization of the Mediterranean basin in terms of Temperature Humidity Index (THI) and to establish relationships between season/THI and mortality in dairy cattle bred in an Italian geographic area with a high concentration of dairy farms. THI variability and scenarios should be taken into careful consideration by farmers and policy makers operating in Mediterranean countries when planning investments. Investments should at least partially be directed to implementation of adaptation measures, which may support farmers in the transition to climate-smart agriculture and help them to alleviate the impact of hot extremes on animal welfare, performance and health. In addition, measures should be developed appropriate adaptation to the specific contexts in terms of culture, society, or political systems, which can contribute to environmental sustainability and economic development and fighting poverty.