WorldWideScience

Sample records for humid subpolar climate

  1. Uniform climate development between the subtropical and subpolar Northeast Atlantic across marine isotope stage 11

    Directory of Open Access Journals (Sweden)

    J. P. Helmke

    2008-09-01

    Full Text Available Proxy records from a core site off Northwest Africa were generated and compared with data from the subpolar Northeast Atlantic to unravel some main climatic features of interglacial marine isotope stage (MIS 11 (423–362 ka. The records point to an almost 25 kyr lasting full interglacial period during stage 11 that was preceded by a considerably long glacial-interglacial transition (Termination V. Off NW Africa, a strong reduction of terrestrially derived iron input is noted after 420 ka suggesting a pronounced increase in continental humidity and vegetation cover over Northwest Africa. In analogy to the Holocene climate of the region, this early wet phase of MIS 11 was likely associated with enhanced influence of the West African monsoon system on the Saharan-Sahel region which led to both a reduction in trade wind intensity off NW Africa and the formation of sapropel S11 in the Mediterranean Sea. A detailed comparison with data from the subpolar North Atlantic indicates a remarkable coherent timing for the main environmental changes in both regions giving evidence for strong interglacial climate connection between the low and high latitude North Atlantic. Although our records of MIS 11 compare well with the Holocene in terms of some major climate characteristics there are distinct differences in the temporal evolution of each peak warm interval. This suggests that care should be taken when using MIS 11 as analogue to forecast future interglacial conditions.

  2. CCSM3 simulation of pacific multi-decadal climate variability: the role of subpolar North Pacific Ocean

    International Nuclear Information System (INIS)

    Zhong, Y; Liu, Z

    2008-01-01

    Previous analyses of the CCSM3 standard integration have revealed pronounced multidecadal variability in the Pacific climate system. The purpose of the present work is to investigate the physical mechanism underlying the Pacific multidecadal variability (PMV) using specifically designed sensitivity experiments. A novel mechanism is advanced, characterized by a crucial role of the subpolar North Pacific Ocean. The multidecadal signal in ocean temperature and salinity fields is found to originate from the subsurface of the subpolar North Pacific, as result of the wave adjustment to the preceding basin-scale wind curl forcing. The multidecadal signal then ascends to the surface and is amplified through local temperature/salinity convective feedback. Along the southward Oyashio current, the anomaly travels to the Kuroshio Extension (KOE) region and is further intensified through a similar convective feedback in addition to the wind-evaporation-sea surface temperature feedback. The temperature anomaly in the KOE is able to feed back to the large-scale atmospheric circulation, inducing wind curl anomaly over the subpolar region, which in turn generates anomalous oceanic circulation and causes temperature/salinty variability in the subpolar subsurface. Thereby, a closed loop of PMV is established, in the form of a subpolar delayed oscillator

  3. Climate change, humidity, and mortality in the United States

    Science.gov (United States)

    Barreca, Alan I.

    2014-01-01

    This paper estimates the effects of humidity and temperature on mortality rates in the United States (c. 1973–2002) in order to provide an insight into the potential health impacts of climate change. I find that humidity, like temperature, is an important determinant of mortality. Coupled with Hadley CM3 climate-change predictions, I project that mortality rates are likely to change little on the aggregate for the United States. However, distributional impacts matter: mortality rates are likely to decline in cold and dry areas, but increase in hot and humid areas. Further, accounting for humidity has important implications for evaluating these distributional effects. PMID:25328254

  4. Investigating atrium in hot and humid climate and providing ...

    African Journals Online (AJOL)

    Atrium has thermal comfort space since the old time by two methods of greenhouse effect and chimney effect. Now these questions are raised: What impact does atrium have in terms of performance in reducing energy consumption in buildings and how is the performance of atrium in the hot and humid climate, and how it ...

  5. Cropping Systems and Climate Change in Humid Subtropical Environments

    Directory of Open Access Journals (Sweden)

    Ixchel M. Hernandez-Ochoa

    2018-02-01

    Full Text Available In the future, climate change will challenge food security by threatening crop production. Humid subtropical regions play an important role in global food security, with crop rotations often including wheat (winter crop and soybean and maize (summer crops. Over the last 30 years, the humid subtropics in the Northern Hemisphere have experienced a stronger warming trend than in the Southern Hemisphere, and the trend is projected to continue throughout the mid- and end of century. Past rainfall trends range, from increases up to 4% per decade in Southeast China to −3% decadal decline in East Australia; a similar trend is projected in the future. Climate change impact studies suggest that by the middle and end of the century, wheat yields may not change, or they will increase up to 17%. Soybean yields will increase between 3% and 41%, while maize yields will increase by 30% or decline by −40%. These wide-ranging climate change impacts are partly due to the region-specific projections, but also due to different global climate models, climate change scenarios, single-model uncertainties, and cropping system assumptions, making it difficult to make conclusions from these impact studies and develop adaptation strategies. Additionally, most of the crop models used in these studies do not include major common stresses in this environment, such as heat, frost, excess water, pests, and diseases. Standard protocols and impact assessments across the humid subtropical regions are needed to understand climate change impacts and prepare for adaptation strategies.

  6. Compact Buried Ducts in a Hot-Humid Climate House

    Energy Technology Data Exchange (ETDEWEB)

    Mallay, Dave [Home Innovation Research Labs, Upper Marlboro, MD (United States)

    2016-01-07

    "9A system of compact, buried ducts provides a high-performance and cost-effective solution for delivering conditioned air throughout the building. This report outlines research activities that are expected to facilitate adoption of compact buried duct systems by builders. The results of this research would be scalable to many new house designs in most climates and markets, leading to wider industry acceptance and building code and energy program approval. The primary research question with buried ducts is potential condensation at the outer jacket of the duct insulation in humid climates during the cooling season. Current best practices for buried ducts rely on encapsulating the insulated ducts with closed-cell spray polyurethane foam insulation to control condensation and improve air sealing. The encapsulated buried duct concept has been analyzed and shown to be effective in hot-humid climates. The purpose of this project is to develop an alternative buried duct system that performs effectively as ducts in conditioned space - durable, energy efficient, and cost-effective - in a hot-humid climate (IECC warm-humid climate zone 3A) with three goals that distinguish this project: 1) Evaluation of design criteria for buried ducts that use common materials and do not rely on encapsulation using spray foam or disrupt traditional work sequences; 2) Establishing design criteria for compact ducts and incorporate those with the buried duct criteria to further reduce energy losses and control installed costs; 3) Developing HVAC design guidance for performing accurate heating and cooling load calculations for compact buried ducts.

  7. Impacts of Present and Future Climate Variability On Agriculture and Forestry in the Humid and Sub-Humid Tropics

    International Nuclear Information System (INIS)

    Zhao, Y.; Wang, C.; Wang, S.; Tibig, Lourdes V.

    2005-01-01

    Although there are different results from different studies, most assessments indicate that climate variability would have negative effects on agriculture and forestry in the humid and sub-humid tropics. Cereal crop yields would decrease generally with even minimal increases in temperature. For commercial crops, extreme events such as cyclones, droughts and floods lead to larger damages than only changes of mean climate. Impacts of climate variability on livestock mainly include two aspects; impacts on animals such as increase of heat and disease stress-related death, and impacts on pasture. As to forestry, climate variability would have negative as well as some positive impacts on forests of humid and sub-humid tropics. However, in most tropical regions, the impacts of human activities such as deforestation will be more important than climate variability and climate change in determining natural forest cover

  8. Thermal Effectiveness of Wall Indoor Fountain in Warm Humid Climate

    Science.gov (United States)

    Seputra, J. A. P.

    2018-03-01

    Nowadays, many buildings wield indoor water features such as waterfalls, fountains, and water curtains to improve their aesthetical value. Despite the provision of air cooling due to water evaporation, this feature also has adverse effect if applied in warm humid climate since evaporation might increase air humidity beyond the comfort level. Yet, there are no specific researches intended to measure water feature’s effect upon its thermal condition. In response, this research examines the influence of evaporative cooling on indoor wall fountain toward occupant’s thermal comfort in warm humid climate. To achieve this goal, case study is established in Waroeng Steak Restaurant’s dining room in Surakarta-Indonesia. In addition, SNI 03-6572-2001 with comfort range of 20.5–27.1°C and 40-60% of relative humidity is utilized as thermal criterion. Furthermore, Computational Fluid Dynamics (CFD) is employed to process the data and derive conclusions. Research variables are; feature’s height, obstructions, and fan types. As results, Two Bumps Model (ToB) is appropriate when employs natural ventilation. However, if the room is mechanically ventilated, Three Bumps Model (TeB) becomes the best choice. Moreover, application of adaptive ventilation is required to maintain thermal balance.

  9. Energy-Efficient Management of Mechanical Ventilation and Relative Humidity in Hot-Humid Climates

    Energy Technology Data Exchange (ETDEWEB)

    Withers, Jr., Charles R. [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States)

    2016-12-01

    In hot and humid climates, it is challenging to energy-efficiently maintain indoor RH at acceptable levels while simultaneously providing required ventilation, particularly in high performance low cooling load homes. The fundamental problem with solely relying on fixed capacity central cooling systems to manage moisture during low sensible load periods is that they are oversized for cooler periods of the year despite being 'properly sized' for a very hot design cooling day. The primary goals of this project were to determine the impact of supplementing a central space conditioning system with 1) a supplemental dehumidifier and 2) a ductless mini-split on seasonal energy use and summer peak power use as well as the impact on thermal distribution and humidity control inside a completely furnished lab home that was continuously ventilated in accordance with ASHRAE 62.2-2013.

  10. Hygroscopical behaviour of basic electrodes in a tropical humid climate

    International Nuclear Information System (INIS)

    Valencia, E.; Galeano, N.J.

    1993-01-01

    The study of the wetting kynetics of basic electrodes in a tropical humid climate is very important since the water contained in them is the main source for the atomic hydrogen absorbed by the fused metal during electric arc welding. It is also the origin of multiple defects in the added metal. A calculating method is established for evaluating the kynetics of wetness incorporation to the coating of basic electrodes exposed to a humid tropical climate. The method is based on the Fick's diffusion equation for both adequate system geometry and boundary conditions, which allows the evaluation of the effective diffusion coefficient and critical times of exposure to the different environments, along with the packing and storage conditions of electrodes. (Author)

  11. PREFACE: Ocean and climate changes in polar and sub-polar environments: proceedings from the 2010 IODP-Canada/ECORD summer school

    Science.gov (United States)

    St-Onge, Guillaume; Veiga-Pires, Cristina; Solignac, Sandrine

    2011-05-01

    IODP logoECORD logo The European Consortium for Ocean Drilling Program (ECORD), the Canadian Consortium for Ocean Drilling (CCOD), the Network of the Universités du Québec (UQ), the Université du Québec à Montréal (UQAM) and GEOTOP sponsored, in 2010, a summer school entitled 'Ocean and climate changes in polar and sub-polar environments'. This summer school took place from 27 June to 12 July in Rimouski, Québec city and Montréal (Quebec, Canada) and was attended by nineteen students and postdoctoral fellows from seven countries: Canada, France, Germany, UK, Serbia, Portugal and the USA. Lectures, hands-on laboratory exercises and laboratory visits were conducted at the Institut des Sciences de la Mer de Rimouski (ISMER), Institut National de la Recherche Scientifique - Centre Eau Terre Environnement (INRS-ETE) and UQAM, in addition to two field trips and a short geological and geophysical cruise on board the R/V Coriolis II in the St Lawrence Estuary and Saguenay Fjord. During the summer school, more than twenty researchers gave lectures on the use of several paleoceanographic and geophysical techniques to reconstruct ocean and climate changes in polar and sub-polar environments. Some of these lectures are presented as short review papers in this volume. They are intended to portray a brief, but state-of-the-art overview of an array of techniques applied to Arctic and sub-Arctic environments, as well as the geological background information needed by the summer school participants to put the scientific expedition and fieldwork into context. The volume begins with a view on the great challenges and key issues to be addressed in the Arctic Ocean (Stein) in the forthcoming years and is followed by a review (O'Regan) on Late Cenozoic paleoceanography of the Central Arctic. The two subsequent papers (St-Onge et al and de Vernal et al) deal with the oceanographic, paleoceanographic and geological context of the Saguenay Fjord, and St Lawrence Estuary and Gulf

  12. Migration of heavy natural radionuclides in a humid climatic zone

    International Nuclear Information System (INIS)

    Titaeva, N.A.; Alexakhin, R.M.; Taskaev, A.I.; Maslov, V.I.

    1980-01-01

    Regularities and biochemical peculiarities of the migrations of heavy natural radionuclides in the environment are examined, with special reference to two regions in a humid climatic zone representing natural patterns of radionuclide distribution and to four plots artificially contaminated with high levels of natural radioactivity more than 20 years previously. It was determined that the migration of thorium, uranium, and radium isotopes through the rock-water-soil-plant system is dependent on many physiochemical properties of these radionuclides, their compounds, and the local environment. Isotopic activity ratios provide a useful tool for studying the direction of radionuclide migration and its influence on observed distribution patterns

  13. First stages of zinc runoff in humid tropical climate

    International Nuclear Information System (INIS)

    Meraz, E.; Veleva, L.; Acosta, M.

    2007-01-01

    Frequently used metals in building application are Zinc and hot dip galvanized steel. The zinc has a relatively good atmospheric resistance, due to its oxidation in air and formation of protective layer. However, some of the zinc corrosion products can be dissolved by pluvial precipitations and water condensed on the metal surface. This process is called metal runoff. In order to estimate el zinc runoff in humid tropical climate, since its firs stages, samples of pure zinc and hot dip galvanized steel have been exposed during 2 years in outdoor atmosphere (rural and urban). The data reveal high annual values of zinc runoff (8,20-12,40±0.30 g/m''2 ano), being this process 80% of total mass loss of corroded zinc. The runoff and corrosion processes are more accelerated for zinc, than that of galvanized steel. The principal factors that control the runoff process are discussed. (Author) 48 refs

  14. Development of Smart Ventilation Control Algorithms for Humidity Control in High-Performance Homes in Humid U.S. Climates

    Energy Technology Data Exchange (ETDEWEB)

    Less, Brennan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ticci, Sara [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-04-11

    Past field research and simulation studies have shown that high performance homes experience elevated indoor humidity levels for substantial portions of the year in humid climates. This is largely the result of lower sensible cooling loads, which reduces the moisture removed by the cooling system. These elevated humidity levels lead to concerns about occupant comfort, health and building durability. Use of mechanical ventilation at rates specified in ASHRAE Standard 62.2-2013 are often cited as an additional contributor to humidity problems in these homes. Past research has explored solutions, including supplemental dehumidification, cooling system operational enhancements and ventilation system design (e.g., ERV, supply, exhaust, etc.). This project’s goal is to develop and demonstrate (through simulations) smart ventilation strategies that can contribute to humidity control in high performance homes. These strategies must maintain IAQ via equivalence with ASHRAE Standard 62.2-2013. To be acceptable they must not result in excessive energy use. Smart controls will be compared with dehumidifier energy and moisture performance. This work explores the development and performance of smart algorithms for control of mechanical ventilation systems, with the objective of reducing high humidity in modern high performance residences. Simulations of DOE Zero-Energy Ready homes were performed using the REGCAP simulation tool. Control strategies were developed and tested using the Residential Integrated Ventilation (RIVEC) controller, which tracks pollutant exposure in real-time and controls ventilation to provide an equivalent exposure on an annual basis to homes meeting ASHRAE 62.2-2013. RIVEC is used to increase or decrease the real-time ventilation rate to reduce moisture transport into the home or increase moisture removal. This approach was implemented for no-, one- and two-sensor strategies, paired with a variety of control approaches in six humid climates (Miami

  15. Climate risk assessment in museums : degradation risks determined from temperature and relative humidity data

    NARCIS (Netherlands)

    Martens, M.H.J.

    2012-01-01

    The main subject of this thesis is the determination of climate risks to objects in museums on the basis of measured and/or simulated temperature and relative humidity data. The focus is on the quantification of climate related risks for the preservation quality of indoor climate in Dutch museums.

  16. Sealed Attics Exposed to Two Years of Weathering in a Hot and Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Miller, William A [ORNL; Railkar, Sudhir [GAF; Shiao, Ming C [ORNL; Desjarlais, Andre Omer [ORNL

    2016-01-01

    Field studies in a hot, humid climate were conducted to investigate the thermal and hygrothermal performance of ventilated attics and non-ventilated semi-conditioned attics sealed with open-cell and with closed-cell spray polyurethane foam insulation. Moisture pin measurements made in the sheathing and absolute humidity sensor data from inside the foam and from the attic air show that moisture is being stored in the foam. The moisture in the foam diffuses to and from the sheathing dependent on the pressure gradient at the foam-sheathing interface which is driven by the irradiance and night-sky radiation. Ventilated attics in the same hot, humid climate showed less moisture movement in the sheathing than those sealed with either open- or closed-cell spray foam. In the ventilated attics the relative humidity drops as the attic air warms; however, the opposite was observed in the sealed attics. Peaks in measured relative humidity in excess of 80 90% and occasionally near saturation (i.e., 100%) were observed from solar noon till about 8 PM on hot, humid days. The conditioned space of the test facility is heated and cooled by an air-to-air heat pump. Therefore the partial pressure of the indoor air during peak irradiance is almost always less than that observed in the sealed attics. Field data will be presented to bring to light the critical humidity control issues in sealed attics exposed to hot, humid climates.

  17. Building America Case Study: Energy Efficient Management of Mechanical Ventilation and Relative Humidity in Hot-Humid Climates, Cocoa, Florida

    Energy Technology Data Exchange (ETDEWEB)

    2017-01-01

    In hot and humid climates, it is challenging to energy-efficiently maintain indoor RH at acceptable levels while simultaneously providing required ventilation, particularly in high performance low cooling load homes. The fundamental problem with solely relying on fixed capacity central cooling systems to manage moisture during low sensible load periods is that they are oversized for cooler periods of the year despite being 'properly sized' for a very hot design cooling day. The primary goals of this project were to determine the impact of supplementing a central space conditioning system with 1) a supplemental dehumidifier and 2) a ductless mini-split on seasonal energy use and summer peak power use as well as the impact on thermal distribution and humidity control inside a completely furnished lab home that was continuously ventilated in accordance with ASHRAE 62.2-2013.

  18. Performance Evaluation of a Hot-Humid Climate Community

    Energy Technology Data Exchange (ETDEWEB)

    Osser, R.; Kerrigan, P.

    2012-02-01

    Project Home Again is a development in New Orleans, LA created to provide new homes to victims of Hurricane Katrina. Building Science Corporation acted as a consultant for the project, advocating design strategies for durability, flood resistance, occupant comfort, and low energy use while maintaining cost effectiveness. These techniques include the use of high density spray foam insulation, LoE3 glazing, and supplemental dehumidification to maintain comfortable humidity levels without unnecessary cooling.

  19. Controlling indoor climate. Passive cooling of residential buildings in hot-humid climates in China

    Energy Technology Data Exchange (ETDEWEB)

    Zhiwu, Wang

    1996-10-01

    Overheating is a paramount problem in residential buildings in hot and humid climates in China during summer. This study aims to deal with the overheating problem and the problem of poor air quality in dwellings. The main objective is to improve indoor thermal conditions by passive cooling approaches, climatisation techniques in buildings without auxiliary cooling from air conditioning equipment. This thesis focuses on the study of cross-ventilation in apartments, which is one of the most effective ways of natural cooling in a hot humid climate, but is also one of the least understood parts in controlling indoor climate. The Computational Fluid Dynamics (CFD) technique is used, which is a new approach, since cross-ventilation studies have been conventionally made by wind tunnel tests. The validations of the CFD technique are examined by a comparison between wind tunnel tests and computer simulations. The factors influencing indoor air movement are investigated for a single room. Cross-ventilation in two apartments is studied, and the air change efficiency in a Chinese kitchen is calculated with CFD techniques. The thermal performance of ventilated roofs, a simple and widely used type of roof in the region, is specially addressed by means of a full-scale measurement, wind tunnel tests and computer simulations. An integrated study of passive cooling approaches and factors affecting indoor thermal comfort is carried out through a case study in a southern Chinese city, Guangzhou. This thesis demonstrates that passive cooling measure have a high potential in significantly improving indoor thermal conditions during summer. This study also gives discussions and conclusions on the evaluation of indoor thermal environment; effects influencing cross-ventilation in apartments; design guidelines for ventilated roofs and an integrated study of passive cooling. 111 refs, 83 figs, 65 tabs

  20. Experimental performance of evaporative cooling pad systems in greenhouses in humid subtropical climates

    International Nuclear Information System (INIS)

    Xu, J.; Li, Y.; Wang, R.Z.; Liu, W.; Zhou, P.

    2015-01-01

    Highlights: • Experimental performance of evaporative cooling in humid climate is investigated. • 5 working modes are studied in the greenhouse. • Vertical and horizontal temperature and relative humidity variations are analysed. • Indoor temperature can be kept in required level by proper working modes. - Abstract: To solve the overheating problem caused by the solar radiation and to keep the indoor temperature and humidity at a proper level for plants or crops, cooling technologies play vital role in greenhouse industry, and among which evaporative cooling is one of the most commonly-used methods. However, the main challenge of the evaporative cooling is its suitability to local climatic and agronomic condition. In this study, the performance of evaporative cooling pads was investigated experimentally in a 2304-m 2 glass multi-span greenhouse in Shanghai in the southeast of China. Temperature and humidity distributions were measured and reported for different working modes, including the use of evaporative cooling alone and the use of evaporative cooling with shading or ventilation. These experiments were conducted in humid subtropical climates where were considered unfavourable for evaporative cooling pad systems. Quantified analyses from the energy perspective are also made based on the experimental results and the evaporative cooling fan–pad system is demonstrated to be an effective option for greenhouse cooling even in the humid climate. Suggestions and possible solutions for further improving the performance of the system are proposed. The results of this work will be useful for the optimisation of the energy management of greenhouses in humid climates and for the validation of the mathematical model in future work

  1. Energy analysis of the personalized ventilation system in hot and humid climates

    DEFF Research Database (Denmark)

    Schiavon, S.; Melikov, Arsen Krikor; Sekhar, C.

    2010-01-01

    , inhaled air quality, thermal comfort, and self-estimated productivity. Little is known about its energy performance. In this study, the energy consumption of a personalized ventilation system introduced in an office building located in a hot and humid climate (Singapore) has been investigated by means...... effectiveness of PV; (b) increasing the maximum allowed room air temperature due to PV capacity to control the microclimate; (c) supplying the outdoor air only when the occupant is at the desk. The strategy to control the supply air temperature does not affect the energy consumption in a hot and humid climate....

  2. Compact Buried Ducts in a Hot-Humid Climate House

    Energy Technology Data Exchange (ETDEWEB)

    Mallay, D. [Home Innovation Research Labs, Upper Marlboro, MD (United States)

    2016-01-01

    A system of compact, buried ducts provides a high-performance and cost-effective solution for delivering conditioned air throughout the building. This report outlines research activities that are expected to facilitate adoption of compact buried duct systems by builders. The results of this research would be scalable to many new house designs in most climates and markets, leading to wider industry acceptance and building code and energy program approval.

  3. Building Material Preferences in Warm-Humid and Hot-Dry Climates ...

    African Journals Online (AJOL)

    dry climates in Ghana. Using a combination of closed and open-ended questionnaires, a total of 1281 participants (473 adults and 808 youth) were recruited in Ghana in a two-month survey in Kumasi and Tamale representing the warm-humid ...

  4. Research on trend of warm-humid climate in Central Asia

    Science.gov (United States)

    Gong, Zhi; Peng, Dailiang; Wen, Jingyi; Cai, Zhanqing; Wang, Tiantian; Hu, Yuekai; Ma, Yaxin; Xu, Junfeng

    2017-07-01

    Central Asia is a typical arid area, which is sensitive and vulnerable part of climate changes, at the same time, Central Asia is the Silk Road Economic Belt of the core district, the warm-humid climate change will affect the production and economic development of neighboring countries. The average annual precipitation, average anneal temperature and evapotranspiration are the important indexes to weigh the climate change. In this paper, the annual precipitation, annual average temperature and evapotranspiration data of every pixel point in Central Asia are analyzed by using long-time series remote sensing data to analyze the trend of warm and humid conditions. Finally, using the model to analyzed the distribution of warm-dry trend, the warm-wet trend, the cold-dry trend and the cold-wet trend in Central Asia and Xinjiang area. The results showed that most of the regions of Central Asia were warm-humid and warm-dry trends, but only a small number of regions showed warm-dry and cold-dry trends. It is of great significance to study the climatic change discipline and guarantee the ecological safety and improve the ability to cope with climate change in the region. It also provide scientific basis for the formulation of regional climate change program. The first section in your paper

  5. Potential of district cooling in hot and humid climates

    DEFF Research Database (Denmark)

    Dominkovic, Dominik Franjo; Rashid, K. A. Bin Abdul; Romagnoli, A.

    2017-01-01

    Efficiently utilizing energy that is currently being wasted can significantly increase energy efficiency of the system, as well as reduce the carbon footprint. In hot climates with large cooling demands, excess waste heat can be utilized via absorption chillers to generate cold. Moreover, cold from...... liquefied natural gas gasification process can further provide energy source for meeting the cold demand. In order to connect the large sources of waste heat and cold energy with customers demanding the cold, a significant investment in district cooling grid is a necessity. In order to deal...

  6. Climatic Reliability of Electronics: Early Prediction and Control of Contamination and humidity effects

    DEFF Research Database (Denmark)

    Verdingovas, Vadimas

    were to a significant extent guided by the climatic reliability issues the electronic companies are currently facing. The research in this thesis is focused on the synergistic effects of process related contamination, humidity, potential bias, and PCBA design related aspects, while various tests...... assuming parasitic circuit due to water layer formation on the PCBA surface. The chapters 2-5 review the factors influencing the climatic reliability of electronics namely humidity interaction with materials and ionic contamination on the PCBA surface, common types and sources of ionic contamination...... in electronics, the test methods and techniques, and failure mechanisms related to climate and contamination. Chapter 6 summarizes the materials and experimental methods employed in this thesis. The results of various investigations are presented as individual research papers as published or in the draft form...

  7. Practices for Alleviating Heat Stress of Dairy Cows in Humid Continental Climates: A Literature Review

    Science.gov (United States)

    Fournel, Sébastien; Ouellet, Véronique; Charbonneau, Édith

    2017-01-01

    Simple Summary The severity of heat stress issues on dairy cows will increase as global warming progresses. Fortunately, major advances in environmental management, including fans, misters, sprinklers, and cooled waterbeds, can attenuate the effects of thermal stress on cow health, production, and reproduction. These cooling systems were, however, tested in subtropical areas and their efficiency in northern regions is uncertain. This article assesses the potential of existing technologies to cool cows in humid continental climates through calculation of heat stress indices. Abstract Heat stress negatively affects the health and performance of dairy cows, resulting in considerable economic losses for the industry. In future years, climate change will exacerbate these losses by making the climate warmer. Physical modification of the environment is considered to be the primary means of reducing adverse effects of hot weather conditions. At present, to reduce stressful heat exposure and to cool cows, dairy farms rely on shade screens and various forms of forced convection and evaporative cooling that may include fans and misters, feed-line sprinklers, and tunnel- or cross-ventilated buildings. However, these systems have been mainly tested in subtropical areas and thus their efficiency in humid continental climates, such as in the province of Québec, Canada, is unclear. Therefore, this study reviewed the available cooling applications and assessed their potential for northern regions. Thermal stress indices such as the temperature-humidity index (THI) were used to evaluate the different cooling strategies. PMID:28468329

  8. Energy and Economic Evaluation of Green Roofs for Residential Buildings in Hot-Humid Climates

    OpenAIRE

    Abubakar S. Mahmoud; Muhammad Asif; Mohammad A. Hassanain; Mohammad O. Babsail; Muizz O. Sanni-Anibire

    2017-01-01

    Green roofs may be considered a passive energy saving technology that also offer benefits like environmental friendliness and enhancement of aesthetic and architectural qualities of buildings. This paper examines the energy and economic viability of the green roof technology in the hot humid climate of Saudi Arabia by considering a modern four bedroom residential building in the city of Dhahran as a case study. The base case and green roof modelling of the selected building has been developed...

  9. 40% Whole-House Energy Savings in the Hot-Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2011-09-01

    This guide book is a resource to help builders design and construct highly energy-efficient homes, while addressing building durability, indoor air quality, and occupant health, safety, and comfort. With the measures described in this guide, builders in the hot-humid climate can build homes that achieve whole house energy savings of 40% over the Building America benchmark (the 1993 Model Energy Code) with no added overall costs for consumers.

  10. 40% Whole-House Energy Savings in the Mixed-Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Baechler, Michael C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gilbride, T. L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hefty, M. G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cole, P. C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Adams, K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Butner, R. S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ortiz, S. J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Love, Pat M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2011-09-01

    This guide book is a resource to help builders design and construct highly energy-efficient homes, while addressing building durability, indoor air quality, and occupant health, safety, and comfort. With the measures described in this guide, builders in the mixed-humid climate can build homes that achieve whole house energy savings of 40% over the Building America benchmark (the 1993 Model Energy Code) with no added overall costs for consumers.

  11. Effect of climate on the seminal characteristics of boars in a region of humid tropical forest

    International Nuclear Information System (INIS)

    Henao Restrepo, Guillermo; Trujillo Aramburo, Luis Emilio; Buritica Henao, Maria Elizabet; Sierra Perez, Carlos Ignacio; Correa Londono, Guillermo; Gonzalez Boto, Oscar Domingo

    2004-01-01

    In a region of humid tropical forest, ten boars of from 12 to 24 months of age were selected to evaluate the effect of climatic variables measured on the day of semen collection and for each of preceding 45 days. On seminal characteristics, the variability of each characteristic was separated into an intra individual component and an interindividual component, using maximum likelihood estimators (PROC VARCOMP of SAS). In order to relate the seminal characteristics with the climatic variables, morphological abnormalities were grouped according to the affected spermatic region, into head. Midsection and main section abnormalities; the other characteristics were evaluated without any modification. Possible correlations between seminal characteristics and climatic variables were evaluated. In a total of 298 ejaculates collected weekly during a period of 30 weeks, except for total volume and morphological abnormalities. The seminal characteristics presented low or moderate intra and interindividual variation and were similar to those found in other latitudes, with a tendency to present greater seminal volumes and concentrations maximum temperature minimum temperature. Range among temperatures. Relative humidity and precipitation of the day of the semen collection and on each of the preceding 45 days had low effects on the seminal characteristics. It is possible that the boars in warm humid tropical areas develop a high level of adaptation that permits an adequate testicular thermoregulation that favors the spermatogenic function of the seminiferous tubules in a way that does not perceptibly affect production the seminal quality

  12. Moisture Performance of Energy-Efficient and Conventional Wood-Frame Wall Assemblies in a Mixed-Humid Climate

    Science.gov (United States)

    Samuel Glass; Vladimir Kochkin; S. Drumheller; Lance Barta

    2015-01-01

    Long-term moisture performance is a critical consideration for design and construction of building envelopes in energy-efficient buildings, yet field measurements of moisture characteristics for highly insulated wood-frame walls in mixed-humid climates are lacking. Temperature, relative humidity, and moisture content of wood framing and oriented strand board (OSB)...

  13. Comfort in High-Performance Homes in a Hot-Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Poerschke, A. [IBACOS, Inc., Pittsburgh, PA (United States); Beach, R. [IBACOS, Inc., Pittsburgh, PA (United States)

    2016-01-01

    IBACOS monitored 37 homes during the late summer and early fall of 2014 in a hot and humid climate to better understand indoor comfort conditions. These homes were constructed in the last several years by four home builders that offered a comfort and performance guarantee for the homes. The homes were located in one of four cities: Tampa, Florida; Orlando, Florida; Houston, Texas; and San Antonio, Texas. Temperature and humidity data were collected from the thermostat and each room of the house using small, battery-powered data loggers. To understand system runtime and its impact on comfort, supply air temperature also was measured on a 1-minute interval. Overall, the group of homes only exceeded a room-to-room temperature difference of 6 degrees Fahrenheit for 5% of the time.

  14. Decline in temperature and humidity increases the occurrence of influenza in cold climate

    Science.gov (United States)

    2014-01-01

    Background Both temperature and humidity may independently or jointly contribute to the risk of influenza infections. We examined the relations between the level and decrease of temperature, humidity and the risk of influenza A and B virus infections in a subarctic climate. Methods We conducted a case-crossover study among military conscripts (n = 892) seeking medical attention due to respiratory symptoms during their military training period and identified 66 influenza A and B cases by PCR or serology. Meteorological data such as measures of average and decline in ambient temperature and absolute humidity (AH) during the three preceding days of the onset (hazard period) and two reference periods, prior and after the onset were obtained. Results The average temperature preceding the influenza onset was −6.8 ± 5.6°C and AH 3.1 ± 1.3 g/m3. A decrease in both temperature and AH during the hazard period increased the occurrence of influenza so that a 1°C decrease in temperature and 0.5 g decrease per m3 in AH increased the estimated risk by 11% [OR 1.11 (1.03 to 1.20)] and 58% [OR 1.58 (1.28 to 1.96)], respectively. The occurrence of influenza infections was positively associated with both the average temperature [OR 1.10 per 1°C (95% confidence interval 1.02 to 1.19)] and AH [OR 1.25 per g/m3 (1.05 to 1.49)] during the hazard period prior to onset. Conclusion Our results demonstrate that a decrease rather than low temperature and humidity per se during the preceding three days increase the risk of influenza episodes in a cold climate. PMID:24678699

  15. Absolute humidity and the human nose: A reanalysis of climate zones and their influence on nasal form and function.

    Science.gov (United States)

    Maddux, Scott D; Yokley, Todd R; Svoma, Bohumil M; Franciscus, Robert G

    2016-10-01

    Investigations into the selective role of climate on human nasal variation commonly divide climates into four broad adaptive zones (hot-dry, hot-wet, cold-dry, and cold-wet) based on temperature and relative humidity. Yet, absolute humidity-not relative humidity-is physiologically more important during respiration. Here, we investigate the global distribution of absolute humidity to better clarify ecogeographic demands on nasal physiology. We use monthly observations from the Climatic Research Unit Timeseries 3 (CRU TS3) database to construct global maps of average annual temperature, relative humidity and absolute humidity. Further, using data collected by Thomson and Buxton (1923) for over 15,000 globally-distributed individuals, we calculate the actual amount of heat and water that must be transferred to inspired air in different climatic regimes to maintain homeostasis, and investigate the influence of these factors on the nasal index. Our results show that absolute humidity, like temperature, generally decreases with latitude. Furthermore, our results demonstrate that environments typically characterized as "cold-wet" actually exhibit low absolute humidities, with values virtually identical to cold-dry environments and significantly lower than hot-wet and even hot-dry environments. Our results also indicate that strong associations between the nasal index and absolute humidity are, potentially erroneously, predicated on individuals from hot-dry environments possessing intermediate (mesorrhine) nasal indices. We suggest that differentially allocating populations to cold-dry or cold-wet climates is unlikely to reflect different selective pressures on respiratory physiology and nasal morphology-it is cold-dry, and to a lesser degree hot-dry environments, that stress respiratory function. Our study also supports assertions that demands for inspiratory modification are reduced in hot-wet environments, and that expiratory heat elimination for thermoregulation is a

  16. Energy Retrofit Field Study and Best Practices in a Hot-Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    McIvaine, J.; Sutherland, K.; Martin, E.

    2013-03-01

    Energy efficiency improvement as a component of comprehensive renovation was investigated under U.S. Department of Energy (DOE) funding of the Building America Partnership for Improved Residential Construction (BA-PIRC). Researchers at the Florida Solar Energy Center (FSEC) worked with affordable housing partners renovating foreclosed homes built from the 1950's through the 2000's in the hot-humid climate (within the Southern census region), primarily in Florida. Researchers targeted a 30% improvement in whole-house energy efficiency along with the health and safety, durability, and comfort guidelines outlined in DOE's Builders Challenge Program (Version 1) Quality Criteria.

  17. Reducing Thermal Losses and Gains With Buried and Encapsulated Ducts in Hot-Humid Climates

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro, C.; Magee, A.; Zoeller, W.

    2013-02-01

    The Consortium for Advanced Residential Buildings (CARB) monitored three houses in Jacksonville, FL, to investigate the effectiveness of encapsulated and encapsulated/buried ducts in reducing thermal losses and gains from ductwork in unconditioned attics. Burying ductwork beneath loose-fill insulation has been identified as an effective method of reducing thermal losses and gains from ductwork in dry climates, but it is not applicable in humid climates where condensation may occur on the outside of the duct jacket. By encapsulating the ductwork in closed cell polyurethane foam (ccSPF) before burial beneath loose-fill mineral fiber insulation, the condensation potential may be reduced while increasing the R-value of the ductwork.

  18. County-Level Climate Uncertainty for Risk Assessments: Volume 12 Appendix K - Historical Rel. Humidity.

    Energy Technology Data Exchange (ETDEWEB)

    Backus, George A.; Lowry, Thomas Stephen; Jones, Shannon M; Walker, La Tonya Nicole; Roberts, Barry L; Malczynski, Leonard A.

    2017-06-01

    This report uses the CMIP5 series of climate model simulations to produce country- level uncertainty distributions for use in socioeconomic risk assessments of climate change impacts. It provides appropriate probability distributions, by month, for 169 countries and autonomous-areas on temperature, precipitation, maximum temperature, maximum wind speed, humidity, runoff, soil moisture and evaporation for the historical period (1976-2005), and for decadal time periods to 2100. It also provides historical and future distributions for the Arctic region on ice concentration, ice thickness, age of ice, and ice ridging in 15-degree longitude arc segments from the Arctic Circle to 80 degrees latitude, plus two polar semicircular regions from 80 to 90 degrees latitude. The uncertainty is meant to describe the lack of knowledge rather than imprecision in the physical simulation because the emphasis is on unfalsified risk and its use to determine potential socioeconomic impacts. The full report is contained in 27 volumes.

  19. Assessment of monitored energy use and thermal comfort conditions in mosques in hot-humid climates

    Energy Technology Data Exchange (ETDEWEB)

    Al-Homoud, Mohammad S.; Abdou, Adel A.; Budaiwi, Ismail M. [Architectural Engineering Department, KFUPM, Dhahran 31261 (Saudi Arabia)

    2009-06-15

    In harsh climatic regions, buildings require air-conditioning in order to provide an acceptable level of thermal comfort. In many situations buildings are over cooled or the HVAC system is kept running for a much longer time than needed. In some other situations thermal comfort is not achieved due to improper operation practices coupled with poor maintenance and even lack it, and consequently inefficient air-conditioning systems. Mosques represent one type of building that is characterized by their unique intermittent operating schedule determined by prayer times, which vary continuously according to the local solar time. This paper presents the results of a study designed to monitor energy use and thermal comfort conditions of a number of mosques in a hot-humid climate so that both energy efficiency and the quality of thermal comfort conditions especially during occupancy periods in such intermittently operated buildings can be assessed accurately. (author)

  20. Climate change scenarios of extreme temperatures and atmospheric humidity for Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Tejeda-Martinez, A. [Departamento de Ciencias Atmosfericas, Universidad Veracruzana, Xalapa, Veracruz (Mexico)]. E-mail: atejeda@uv.mx; Conde-Alvarez, C. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico); Valencia-Treviso, L.E. [Departamento de Ciencias Atmosfericas, Universidad Veracruzana, Xalapa, Veracruz (Mexico)

    2008-10-15

    The following study explores climatic change scenarios of extreme temperature and atmospheric humidity for the 2020 and 2050 decades. They were created for Mexico through the GFDLR30, ECHAM4 and HadCM2 general circulation models. Base scenario conditions were associated with the normal climatological conditions for the period 1961-1990, with a database of 50 surface observatories. It was necessary to empirically estimate the missing data in approximately half of the pressure measurements. For the period 1961-1990, statistical models of the monthly means of maximum and minimum temperatures and atmospheric humidity (relative and specific) were obtained from the observed data of temperature, solar radiation and precipitation. Based on the simulations of the GFDLR30, ECHAM4 and HADCM2 models, a future scenario of monthly means of maximum and minimum temperatures and humidity in climatic change conditions was created. The results shown are for the representative months of winter (January) and summer (July). [Spanish] En este articulo se presentan escenarios de cambio climatico referidos a temperaturas extremas y humedad atmosferica para las decadas de 2020 y 2050. Fueron generados para Mexico a partir de los modelos de circulacion general GFDLR30, ECHAM4 y HADCM2. El escenario base corresponde a las normales climatologicas del periodo 1961-1990 para 50 observatorios de superficie. Para la mitad de ellos fue necesario estimar empiricamente la presion atmosferica a partir de la altitud y para la totalidad se obtuvieron modelos estadisticos de los promedios mensuales de temperaturas maxima y minima asi como de humedad atmosferica (relativa y especifica). Esos modelos estadisticos, combinados con las salidas de los modelos de circulacion general mencionados, produjeron escenarios futuros de medias mensuales de temperaturas extremas y de humedad bajo condiciones de cambio climatico. Se mostraran los resultados para un mes representativo del invierno (enero) y otro del verano

  1. Approaches to 30% Energy Savings at the Community Scale in the Hot-Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Thomas-Rees, S.; Beal, D.; Martin, E.; Fonorow, K.

    2013-03-01

    BA-PIRC has worked with several community-scale builders within the hot humid climate zone to improve performance of production, or community scale, housing. Tommy Williams Homes (Gainesville, FL), Lifestyle Homes (Melbourne, FL), and Habitat for Humanity (various locations, FL) have all been continuous partners of the BA Program and are the subjects of this report to document achievement of the Building America goal of 30% whole house energy savings packages adopted at the community scale. The scope of this report is to demonstrate achievement of these goals though the documentation of production-scale homes built cost-effectively at the community scale, and modeled to reduce whole-house energy use by 30% in the Hot Humid climate region. Key aspects of this research include determining how to evolve existing energy efficiency packages to produce replicable target savings, identifying what builders' technical assistance needs are for implementation and working with them to create sustainable quality assurance mechanisms, and documenting the commercial viability through neutral cost analysis and market acceptance. This report documents certain barriers builders overcame and the approaches they implemented in order to accomplish Building America (BA) Program goals that have not already been documented in previous reports.

  2. The role of groundwater in streamflow in a headwater catchment with sub-humid climate

    Science.gov (United States)

    Liu, Yaping; Tian, Fuqiang; Hu, Hongchang; Tie, Qiang

    2015-04-01

    Recent studies have suggested that bedrock groundwater can exert considerable influence on streamflow in headwater catchments under humid climate. However, study of the role of bedrock groundwater is still challenged due to limited direct observation data. In this study, by utilizing observed hydrometric and hydrochemical data, we aimed at characterize the bedrock groundwater's response to rainfall at hillslope and catchment scales in a small headwater catchment with sub-humid climate. We selected Xitaizi catchment with area of 6.7 km in the earth-rock mountain region, which located in the north of Beijing, China, as study area. The catchment bedrock is mainly consist of fractured granite. Four weather stations were installed to observe the weather condition and soil volumetric water content (VWC) at depth of 10-60 cm with 10-minute interval. Five wells with depth of 10 m were drilled in two slopes to monitor the bedrock water table by pneumatic water gauge. At slope 1, the soil VWC at depth of 10-80 cm were also observed by soil moisture sensors, and surface/subsurface hillslope runoff at three different layers (0-20cm, 20-80cm, 80-300cm) was observed by three recording buckets. Field works were conducted from July 2013 to November 2014. During the period, precipitation, river, spring and groundwater were sampled nearly monthly. Water temperature, electrical conductivity (EC) and pH were measured in site with portable instruments. In addition, the precipitation, river and groundwater were also sampled intensively during two storm events. All the samples were subjected to stable isotope analysis, the samples taken monthly during the period from July 2013 to July 2014 were subjected to hydrochemistry analysis. Our results show that: (1) the bedrock groundwater is the dominant component of streamflow in the headwater catchment with sub-humid climate; (2) stream is recharged by groundwater sourcing from different mountains with different hydrochemistry characteristics

  3. Should Workers Avoid Consumption of Chilled Fluids in a Hot and Humid Climate?

    Directory of Open Access Journals (Sweden)

    Matt B. Brearley

    2017-12-01

    Full Text Available Despite provision of drinking water as the most common method of occupational heat stress prevention, there remains confusion in hydration messaging to workers. During work site interactions in a hot and humid climate, workers commonly report being informed to consume tepid fluids to accelerate rehydration. When questioned on the evidence supporting such advice, workers typically cite that fluid absorption is delayed by ingestion of chilled beverages. Presumably, delayed absorption would be a product of fluid delivery from the gut to the intestines, otherwise known as gastric emptying. Regulation of gastric emptying is multifactorial, with gastric volume and beverage energy density the primary factors. If gastric emptying is temperature dependent, the impact of cooling is modest in both magnitude and duration (≤ 5 minutes due to the warming of fluids upon ingestion, particularly where workers have elevated core temperature. Given that chilled beverages are most preferred by workers, and result in greater consumption than warm fluids during and following physical activity, the resultant increased consumption of chilled fluids would promote gastric emptying through superior gastric volume. Hence, advising workers to avoid cool/cold fluids during rehydration appears to be a misinterpretation of the research. More appropriate messaging to workers would include the thermal benefits of cool/cold fluid consumption in hot and humid conditions, thereby promoting autonomy to trial chilled beverages and determine personal preference. In doing so, temperature-based palatability would be maximized and increase the likelihood of workers maintaining or restoring hydration status during and after their work shift. Keywords: Fluid consumption, gastric emptying, hot and humid conditions, hydration, occupational

  4. Comfort in High-Performance Homes in a Hot-Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Poerschke, A. [IBACOS, Inc., Pittsburgh, PA (United States); Beach, R. [IBACOS, Inc., Pittsburgh, PA (United States)

    2016-01-22

    "9IBACOS monitored 37 homes during the late summer and early fall of 2014 in a hot and humid climate to better understand indoor comfort conditions. These homes were constructed in the last several years by four home builders that offered a comfort and performance guarantee for the homes. The homes were located in one of four cities: Tampa, Florida; Orlando, Florida; Houston, Texas; and San Antonio, Texas. Temperature and humidity data were collected from the thermostat and each room of the house using small, battery-powered data loggers. To understand system runtime and its impact on comfort, supply air temperature also was measured on a 1-minute interval. Overall, the group of homes only exceeded a room-to-room temperature difference of 6 degrees F for 5% of the time. For 80% of the time, the rooms in each house were within 4 degrees F of each other. Additionally, the impact of system runtime on comfort is discussed. Finally, measurements made at the thermostat were used to better understand the occupant operation of each cooling system's thermostat setpoint. Builders were questioned on their perceived impact of offering a comfort and performance guarantee. Their feedback, which generally indicates a positive perception, has been summarized in the report.

  5. The Impact of Climate Change in Rainfall Erosivity Index on Humid Mudstone Area

    Science.gov (United States)

    Yang, Ci-Jian; Lin, Jiun-Chuan

    2017-04-01

    It has been quite often pointed out in many relevant studies that climate change may result in negative impacts on soil erosion. Then, humid mudstone area is highly susceptible to climate change. Taiwan has extreme erosion in badland area, with annual precipitation over 2000 mm/y which is a considerably 3 times higher than other badland areas around the world, and with around 9-13 cm/y in denudation rate. This is the reason why the Erren River, a badland dominated basin has the highest mean sediment yield in the world, over 105 t km2 y. This study aims to know how the climate change would affect soil erosion from the source in the Erren River catchment. Firstly, the data of hourly precipitation from 1992 to 2016 are used to establish the regression between rainfall erosivity index (R, one of component for USLE) and precipitation. Secondly, using the 10 climate change models (provide form IPCC AR5) simulates the changes of monthly precipitation in different scenario from 2017 to 2216, and then over 200 years prediction R values can be use to describe the tendency of soil erosion in the future. The results show that (1) the relationship between rainfall erosion index and precipitation has high correction (>0.85) during 1992-2016. (2) From 2017 to 2216, 7 scenarios show that annual rainfall erosion index will increase over 2-18%. In contrast, the others will decrease over 7-14%. Overall, the variations of annual rainfall erosion index fall in the range of -14 to 18%, but it is important to pay attention to the variation of annual rainfall erosion index in extreme years. These fall in the range of -34 to 239%. This explains the extremity of soil erosion will occur easily in the future. Keywords: Climate Change, Mudstone, Rainfall Erosivity Index, IPCC AR5

  6. Crop coefficients for winter wheat in a sub-humid climate regime

    DEFF Research Database (Denmark)

    Kjærsgaard, Jeppe Hvelplund; Plauborg, Finn; Mollerup, Mikkel

    2008-01-01

    Estimations of evapotranspiration (ET) from natural surfaces are used in a large number of applications such as agricultural water management and water resources planning. Lack of reliable, cheap and easy-to-use instruments, associated with the chaotic and varying nature of the meteorological...... coefficients for a winter wheat crop growing under standard conditions, i.e. not short of water and growing under optimal agronomic conditions, were estimated for a cold sub-humid climate regime. One of the two methods used to estimate ET from a reference crop required net radiation (Rn) as input. Two sets...... of coefficients were used for calculating Rn. Weather data from a meteorological station was used to estimate Rn and ET from the reference crop. The winter wheat ET was measured using an eddy covariance system during the main parts of the growing seasons 2004 and 2005. The meteorological data and field...

  7. Approaches to 30 Percent Energy Savings at the Community Scale in the Hot-Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Thomas-Rees, S. [Building America Partnership for Improved Residential Construction (BA-PIRC), Cocoa, FL (United States); Beal, D. [Building America Partnership for Improved Residential Construction (BA-PIRC), Cocoa, FL (United States); Martin, E. [Building America Partnership for Improved Residential Construction (BA-PIRC), Cocoa, FL (United States)

    2013-03-01

    BA-PIRC has worked with several community-scale builders within the hot humid climate zone to improve performance of production, or community scale, housing. Tommy Williams Homes (Gainesville, FL), Lifestyle Homes (Melbourne, FL), and Habitat for Humanity (various locations, FL) have all been continuous partners of the Building America program and are the subjects of this report to document achievement of the Building America goal of 30% whole house energy savings packages adopted at the community scale. Key aspects of this research include determining how to evolve existing energy efficiency packages to produce replicable target savings, identifying what builders' technical assistance needs are for implementation and working with them to create sustainable quality assurance mechanisms, and documenting the commercial viability through neutral cost analysis and market acceptance. This report documents certain barriers builders overcame and the approaches they implemented in order to accomplish Building America (BA) Program goals that have not already been documented in previous reports.

  8. Rodent communities in the sub-polar Ural mountains

    Directory of Open Access Journals (Sweden)

    Berdyugin, K. I.

    2004-12-01

    Full Text Available Distribution of the rodent communities in the Sub-polar Urals is analysed. This part of the range, between 64° and 66°N, includes the highest peaks, is very scarcely settled and has been rarely studied. However, the area is interesting for biogeography, being a border zone separating European and Siberian lowland faunas. Comparison of results with those from expeditions undertaken in 1927 and in 1972, allows to evaluate changing trends in the local rodent communities, and to relate these trends to changes in the environmental conditions. The results help to emphasize the barrier role played by Sub-polar Urals for the species of rodents inhabiting both sides of the range, and also show the shifting of southern rodent forms northwards, or the moving upwards of other lowland species. This could be seen as an additional evidence of current climate warming trends.

    [fr]
    On analyse la répartition des communautés de rongeurs dans les Durais Subpolaires, une section de la chaîne comprise entre les 64° et les 66° de latitude N. Cette partie est très peu peuplée, elle possède les pics les plus hauts de la chaîne et a été rarement étudiée. Il s'agit d'une région intéressante, car c'est la frontière entre les plaines européennes et les plaines orientales de la Sibérie. En comparant les observations effectuées en 1927 et en 1972 avec celles des dernières années, on peut voir les tendances de changement des groupements de rongeurs de la région, et les interpréter en fonction des changements dans l'environnement. Les résultats permettent de mieux comprendre le rôle de barrière qui jouent les Durais Subpolaires pour les espèces de rongeurs situées d'un coté et d'autre de la chaîne. Aussi, ils permettent de verifier le déplacement vers le nord deformes méridionales et l'élévation en altitude d'autres, ce qui pourrait être vu comme une preuve additionnelle de la tendance au réchauffement global.
    [es]
    Se

  9. Daily indoor-to-outdoor temperature and humidity relationships: a sample across seasons and diverse climatic regions.

    Science.gov (United States)

    Nguyen, Jennifer L; Dockery, Douglas W

    2016-02-01

    The health consequences of heat and cold are usually evaluated based on associations with outdoor measurements collected at a nearby weather reporting station. However, people in the developed world spend little time outdoors, especially during extreme temperature events. We examined the association between indoor and outdoor temperature and humidity in a range of climates. We measured indoor temperature, apparent temperature, relative humidity, dew point, and specific humidity (a measure of moisture content in air) for one calendar year (2012) in a convenience sample of eight diverse locations ranging from the equatorial region (10 °N) to the Arctic (64 °N). We then compared the indoor conditions to outdoor values recorded at the nearest airport weather station. We found that the shape of the indoor-to-outdoor temperature and humidity relationships varied across seasons and locations. Indoor temperatures showed little variation across season and location. There was large variation in indoor relative humidity between seasons and between locations which was independent of outdoor airport measurements. On the other hand, indoor specific humidity, and to a lesser extent dew point, tracked with outdoor, airport measurements both seasonally and between climates, across a wide range of outdoor temperatures. These results suggest that, in general, outdoor measures of actual moisture content in air better capture indoor conditions than outdoor temperature and relative humidity. Therefore, in studies where water vapor is among the parameters of interest for examining weather-related health effects, outdoor measurements of actual moisture content can be more reliably used as a proxy for indoor exposure than the more commonly examined variables of temperature and relative humidity.

  10. Evaluation of the Performance of Houses With and Without Supplemental Dehumidification in a Hot-Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Kerrigan, P.; Norton, P.

    2014-10-01

    This report, Evaluation of the Performance of Houses with and without Supplemental Dehumidification in a Hot-Humid Climate, describes a research study that that was conducted by the Building Science Corporation (BSC) Building America Research Team. BSC seeks to research and report on the field monitoring of the performance of in-situ supplemental dehumidification systems in low energy, high performance, homes in a Hot-Humid climate. The purpose of this research project was to observe and compare the humidity control performance of new, single family, low energy, and high performance, homes. Specifically, the study sought to compare the interior conditions and mechanical systems operation between two distinct groups of houses, homes with a supplemental dehumidifier installed in addition to HVAC system, and homes without any supplemental dehumidification. The subjects of the study were ten single-family new construction homes in New Orleans, LA.Data logging equipment was installed at each home in 2012. Interior conditions and various end-use loads were monitored for one year. In terms of averages, the homes with dehumidifiers are limiting elevated levels of humidity in the living space. However, there was significant variation in humidity control between individual houses. An analysis of the equipment operation did not show a clear correlation between energy use and humidity levels. In general, no single explanatory variable appears to provide a consistent understanding of the humidity control in each house. Indoor humidity is likely due to all of the factors we have examined, and the specifics of how they are used by each occupant.

  11. New Whole-House Solutions Case Study: Compact Buried Ducts in a Hot-Humid Climate House

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-02-18

    With U.S. Department of Energy Building America Program support, Home Innovation Research Labs partnered with K. Hovnanian Homes to demonstrate a new buried-duct design that is durable, energy efficient, and cost-effective in a hot-humid climate.

  12. A newly developed tool for intra-tracheal temperature and humidity assessment in laryngectomized individuals: the Airway Climate Explorer (ACE)

    NARCIS (Netherlands)

    Zuur, J.K.; Muller, S.H.; Jongh, F.H.C.; Horst, M.J. van der; Shehata, M.; Leeuwen, J. van; Sinaasappel, M.; Hilgers, F.J.M.

    2007-01-01

    The aim of this study is to develop a postlaryngectomy airway climate explorer (ACE) for assessment of intratracheal temperature and humidity and of influence of heat and moisture exchangers (HMEs). Engineering goals were within-device condensation prevention and fast response time characteristics.

  13. Assessment of tracheal temperature and humidity in laryngectomized individuals and the influence of heat and moisture exchangers on tracheal climate

    NARCIS (Netherlands)

    Zuur, J.K.; Muller, S.H.; Vincent, A.; Sinaasappel, M.; de Jongh, F.H.C.; Hilgers, F.J.M.

    2008-01-01

    Background The beneficial function of heat and moisture exchangers (HMEs) is undisputed, but knowledge of their effects on intra-airway temperature and humidity is scarce. The aim of this study was to evaluate the clinical applicability of a new airway climate explorer (ACE) and to assess the HME's

  14. Methodology for the preliminary design of high performance schools in hot and humid climates

    Science.gov (United States)

    Im, Piljae

    A methodology to develop an easy-to-use toolkit for the preliminary design of high performance schools in hot and humid climates was presented. The toolkit proposed in this research will allow decision makers without simulation knowledge easily to evaluate accurately energy efficient measures for K-5 schools, which would contribute to the accelerated dissemination of energy efficient design. For the development of the toolkit, first, a survey was performed to identify high performance measures available today being implemented in new K-5 school buildings. Then an existing case-study school building in a hot and humid climate was selected and analyzed to understand the energy use pattern in a school building and to be used in developing a calibrated simulation. Based on the information from the previous step, an as-built and calibrated simulation was then developed. To accomplish this, five calibration steps were performed to match the simulation results with the measured energy use. The five steps include: (1) Using an actual 2006 weather file with measured solar radiation, (2) Modifying lighting & equipment schedule using ASHRAE's RP-1093 methods, (3) Using actual equipment performance curves (i.e., scroll chiller), (4) Using the Winkelmann's method for the underground floor heat transfer, and (5) Modifying the HVAC and room setpoint temperature based on the measured field data. Next, the calibrated simulation of the case-study K-5 school was compared to an ASHRAE Standard 90.1-1999 code-compliant school. In the next step, the energy savings potentials from the application of several high performance measures to an equivalent ASHRAE Standard 90.1-1999 code-compliant school. The high performance measures applied included the recommendations from the ASHRAE Advanced Energy Design Guides (AEDG) for K-12 and other high performance measures from the literature review as well as a daylighting strategy and solar PV and thermal systems. The results show that the net

  15. Indoor climate and moisture durability performances of houses with unvented attic roof constructions in a mixed-humid climate.

    Energy Technology Data Exchange (ETDEWEB)

    Pallin, Simon B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Boudreaux, Philip R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jackson, Roderick K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-10-01

    A sealed or unvented attic is an energy-efficient envelope component that can reduce the amount of energy a house consumes for space conditioning if the air handler and/or ducts are located in the attic. The attic is typically sealed by using spray foam on the underside of the roof deck and covering the soffit, ridge and gable vents to minimize air leakage from the attic to the outside. This approach can save up to 10% in space-conditioning energy when ducts are located in the attic (DOE 2013). Past research done by ORNL and Florida Solar Energy Center suggests that in more hot, humid climates, an unvented attic could potentially create a more humid, uncomfortable living environment than a vented attic (Colon 2011, Boudreaux, Pallin et al. 2013). Research showed that controlling the higher indoor humidity could reduce the energy savings from the sealed, unvented attic, which in turn would decrease the energy savings payback. Research also showed that the roof assembly (5.5 inches of open-cell foam, 1inch of closed-cell foam, OSB, felt paper, and asphalt shingles) stored moisture, thus acting as a moisture buffer. During the fall and winter, the roof assembly stored moisture and during the spring and summer it released moisture. This phenomenon is not seen in a vented attic, in which the air exchange rate to the outside is greater and, in the winter, helps to dehumidify the attic air. It was also seen that in a vented attic, the direction of water vapor diffusion is on average from the attic to the interior of the house. Air leakage from the attic to the interior also occurs during more of the year in a house with an unvented attic than in one with a vented attic. These discoveries show that the moisture dynamics in a house with an unvented attic are much different from those in a house with a vented attic. This study reports on a series of computer model investigations completed to determine the key variables impacting indoor comfort and the durability of roof

  16. Short-Term Test Results. Transitional Housing Energy Efficiency Retrofit in the Hot Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Sutherland, K. [BA-PIRC/Florida Solar Energy Center, Cocoa, FL (United States); Martin, Eric [BA-PIRC/Florida Solar Energy Center, Cocoa, FL (United States)

    2013-02-01

    This project evaluates the renovation of a 5,800 ft2, multi-use facility located in St. Petersburg, on the west coast of central Florida, in the hot humid climate. An optimal package of retrofit measures was designed to deliver 30%-40% annual energy cost savings for this building with annual utility bills exceeding $16,000 and high base load consumption. Researchers projected energy cost savings for potential retrofit measures based on pre-retrofit findings and disaggregated, weather normalized utility bills as a basis for simulation true-up. A cost-benefit analysis was conducted for the seven retrofit measures implemented; adding attic insulation and sealing soffits, tinting windows, improving whole building air-tightness, upgrading heating and cooling systems and retrofitting the air distribution system, replacing water heating systems, retrofitting lighting, and replacing laundry equipment. The projected energy cost savings for the full retrofit package based on a post-retrofit audit is 35%. The building's architectural characteristics, vintage, and residential and commercial uses presented challenges for both economic projections and retrofit measure construction.

  17. Short-Term Test Results: Transitional Housing Energy Efficiency Retrofit in the Hot-Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Sutherland, K.; Martin, E.

    2013-02-01

    This project evaluates the renovation of a 5,800 ft2, multi-use facility located in St. Petersburg, on the west coast of central Florida, in the hot humid climate. An optimal package of retrofit measures was designed to deliver 30-40% annual energy cost savings for this building with annual utility bills exceeding $16,000 and high base load consumption. Researchers projected energy cost savings for potential retrofit measures based on pre-retrofit findings and disaggregated, weather normalized utility bills as a basis for simulation true-up. A cost-benefit analysis was conducted for the seven retrofit measures implemented; adding attic insulation and sealing soffits, tinting windows, improving whole building air-tightness, upgrading heating and cooling systems and retrofitting the air distribution system, replacing water heating systems, retrofitting lighting, and replacing laundry equipment. The projected energy cost savings for the full retrofit package based on a post-retrofit audit is 35%. The building's architectural characteristics, vintage, and residential and commercial uses presented challenges for both economic projections and retrofit measure construction.

  18. Energy and Economic Evaluation of Green Roofs for Residential Buildings in Hot-Humid Climates

    Directory of Open Access Journals (Sweden)

    Abubakar S. Mahmoud

    2017-03-01

    Full Text Available Green roofs may be considered a passive energy saving technology that also offer benefits like environmental friendliness and enhancement of aesthetic and architectural qualities of buildings. This paper examines the energy and economic viability of the green roof technology in the hot humid climate of Saudi Arabia by considering a modern four bedroom residential building in the city of Dhahran as a case study. The base case and green roof modelling of the selected building has been developed with the help of DesignBuilder software. The base case model has been validated with the help of 3-month measured data about the energy consumption without a green roof installed. The result shows that the energy consumption for the base case is 169 kWh/m2 while the energy consumption due to the application of a green roof on the entire roof surface is 110 kWh/m2. For the three investigated green roof options, energy saving is found to be in the range of 24% to 35%. The economic evaluation based on the net present value (NPV approach for 40 years with consideration to other environmental advantages indicates that the benefits of the green roof technology are realized towards the end of the life cycle of the building.

  19. Specifying residential retrofit packages for 30 % reductions in energy consumption in hot-humid climate zones

    Energy Technology Data Exchange (ETDEWEB)

    Burgett, J.M.; Chini, A.R.; Oppenheim, P. [University of Florida, 573 Rinker Hall, Newell Drive, Gainesville, FL 32611 (United States)

    2013-08-15

    The purpose of this research was to demonstrate the application of energy simulation as an effective tool for specifying cost-effective residential retrofit packages that will reduce energy consumption by 30 %. Single-family homes in the hot-humid climate type of the Southeastern USA were used to demonstrate the application. US census data from both state and federal studies were used to create 12 computer simulation homes representing the most common characteristics of single-family houses specific to this area. Well-recognized energy efficiency measures (EEMs) were simulated to determine their cumulative energy reduction potential. Detailed cost estimates were created for cost-to-benefit analysis. For each of the 12 simulated homes, 4 packages of EEMs were created. The four packages provided home owners options for reducing their energy by 30 % along with the estimated up-front cost and simple payback periods. The simple payback period was used to determine how cost-effective a measure was. The packages are specific to a geographic area to provide a higher degree of confidence in the projected cost and energy savings. The study provides a generic methodology to create a similar 30 % energy reduction packages for other locations and a detailed description of a case study to serve as an example. The study also highlights the value that computer simulation models can have to develop energy efficiency packages cost-effectively and specific to home owner's location and housing type.

  20. Energy-Efficient Supermarket Heating, Ventilation, and Air Conditioning in Humid Climates in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Clark, J. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2015-03-01

    Supermarkets are energy-intensive buildings that consume the greatest amount of electricity per square foot of building of any building type in the United States and represent 5% of total U.S. commercial building primary energy use (EIA 2005). Refrigeration and heating, ventilation, and air-conditioning (HVAC) systems are responsible for a large proportion of supermarkets’ total energy use. These two systems sometimes work together and sometimes compete, but the performance of one system always affects the performance of the other. To better understand these challenges and opportunities, the Commercial Buildings team at the National Renewable Energy Laboratory investigated several of the most promising strategies for providing energy-efficient HVAC for supermarkets and quantified the resulting energy use and costs using detailed simulations. This research effort was conducted on behalf of the U.S. Department of Energy (DOE) Commercial Building Partnerships (CBP) (Baechler et al. 2012; Parrish et al. 2013; Antonopoulos et al. 2014; Hirsch et al. 2014). The goal of CBP was to reduce energy use in the commercial building sector by creating, testing, and validating design concepts on the pathway to net zero energy commercial buildings. Several CBP partners owned or operated buildings containing supermarkets and were interested in optimizing the energy efficiency of supermarket HVAC systems in hot-humid climates. These partners included Walmart, Target, Whole Foods Market, SUPERVALU, and the Defense Commissary Agency.

  1. Determination of Optimum Window to External Wall Ratio for Offices in a Hot and Humid Climate

    Directory of Open Access Journals (Sweden)

    Halil Alibaba

    2016-02-01

    Full Text Available Heat loss and gain through windows has a very high impact on the thermal comfort of offices. This paper analyzes a standard low energy consumption university office that has a standard envelope. Dynamic thermal simulations with EDSL Tas software, a predicted mean vote (PMV, and a predicted percentage of dissatisfied (PPD with all local discomfort as stated in ASHRAE, ISO 7730: 2005, EN 15251: 2007 were used for thermal sensation, in order to optimize the best window to external wall proportion in a hot and humid climate that exists in the Famagusta case study. A simulated office building is oriented east to west in order to take advantage of the wind direction. In May 45% (PPD < 6%–0.7% open window, 93% (PPD < 10–0.2 open window, and 97% (PPD < 15%–0.1% open window thermal comfort scores are obtained when the window to external wall ratio (WWR is 10%. In October 43% (PPD < 6%–0.7% open window, 86% (PPD < 10–0.2 open window, and 92% (PPD < 15%–0.1% open window thermal comfort scores are obtained when the WWR is 10%. In September 49% (PPD < 10% full open window and 51% (PPD < 15%–0.1% open window thermal comfort scores are obtained when the WWR is 10%.

  2. Plants for passive cooling. A preliminary investigation of the use of plants for passive cooling in temperate humid climates

    Energy Technology Data Exchange (ETDEWEB)

    Spirn, A W; Santos, A N; Johnson, D A; Harder, L B; Rios, M W

    1981-04-01

    The potential of vegetation for cooling small, detached residential and commercial structures in temperate, humid climates is discussed. The results of the research are documented, a critical review of the literature is given, and a brief review of energy transfer processes is presented. A checklist of design objectives for passive cooling, a demonstration of design applications, and a palette of selected plant species suitable for passive cooling are included.

  3. Potential of indirect evaporative passive cooling with embedded tubes in a humid tropical climate : applications in a typical hot humid climate

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Chavez, J.R. [Univ. Autonoma Metropolitana-Azcapotzalco, Mexico City (Mexico). Dept. de Medio Ambiente, Laboratorio de Investigaciones en Arquitectura Bioclimatica; Givoni, B. [California Univ., Los Angeles, CA (United States); BGU, Beer Sheva (Israel); Viveros, O. [Cristobal Colon Univ., Veracruz (Mexico)

    2009-07-01

    The use of passive cooling techniques in buildings in hot and humid regions can reduce energy consumption while increasing thermal comfort for occupants. A study was conducted in the City of Veracruz, Mexico to investigate the performance of tubes embedded in the roof of the Gulf Meteorological Prevision Centre. Two identical insulated experimental cells were used, one serving as the control and the other one as the test unit, where the technique of embedded tubes in the roof was implemented and investigated during a typical overheating season. Results showed that this indirect evaporative cooling system is an effective strategy to reduce indoor temperatures without increasing the indoor humidity in buildings. The indoor maximum temperature was lowered by 2.72 K in the experimental test cell relative to the control unit. In addition, the resulting reduction of radiant temperatures in the test unit improved the thermal comfort of the occupants. It is expected that the implementation of this passive cooling technique will eventually contribute to reduced energy consumption and less use of air-conditioning systems in buildings, and thereby prevent emission of greenhouse gases to the atmosphere. 9 refs., 1 tab., 6 figs.

  4. Performance evaluation of an indirect pre-cooling evaporative heat exchanger operating in hot and humid climate

    International Nuclear Information System (INIS)

    Cui, X.; Chua, K.J.; Islam, M.R.; Ng, K.C.

    2015-01-01

    Highlights: • An IEHX is introduced as a pre-cooling unit for humid tropical climate. • A computational model is developed to investigate the performance of IEHX. • The air treatment process with condensation from the product air is studied. • The hybrid system shows an appreciable energy saving potential. - Abstract: A hybrid system, that combines an indirect evaporative heat exchanger (IEHX) and a vapor compression system, is introduced for humid tropical climate application. The chief purpose of the IEHX is to pre-cool the incoming air for vapor compression system. In the IEHX unit, the outdoor humid air in the product channel may potentially condense when heat is exchanged with the room exhaust air. A computational model has been developed to theoretically investigate the performance of an IEHX with condensation from the product air by employing the room exhaust air as the working air. We validated the model by comparing its temperature distribution and predicted heat flux against experimental data acquired from literature sources. The numerical model showed good agreement with the experimental findings with maximum average discrepancy of 9.7%. The validated model was employed to investigate the performance of two types of IEHX in terms of the air treatment process, temperature and humidity distribution, cooling effectiveness, cooling capacity, and energy consumption. Simulation results have indicated that the IEHX unit is able to fulfill 47% of the cooling load for the outdoor humid air while incurring a small amount of fan power. Consequently, the hybrid system is able to realize significant energy savings

  5. Building America Residential System Research Results: Achieving 30% Whole House Energy Savings Level in Mixed-Humid Climates; January 2006 - December 2006

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, R. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hendron, R. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Eastment, M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jalalzadeh-Azar, A. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2006-12-01

    This report summarizes research results for the 30% energy savings level and demonstrates that lead builders can successfully provide 30% homes in the Mixed-Humid Climate Region on a cost-neutral basis.

  6. Building America Best Practices Series: Volume 4; Builders and Buyers Handbook for Improving New Home Efficiency, Comfort, and Durability in the Mixed-Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    None

    2005-09-01

    This guide book is a resource to help builders large and small build high-quality, energy-efficient homes that achieve 30% energy savings in space conditioning and water heating in the mixed-humid climate region.

  7. Effect of wind speed and relative humidity on atmospheric dust concentrations in semi-arid climates.

    Science.gov (United States)

    Csavina, Janae; Field, Jason; Félix, Omar; Corral-Avitia, Alba Y; Sáez, A Eduardo; Betterton, Eric A

    2014-07-15

    Atmospheric particulate have deleterious impacts on human health. Predicting dust and aerosol emission and transport would be helpful to reduce harmful impacts but, despite numerous studies, prediction of dust events and contaminant transport in dust remains challenging. In this work, we show that relative humidity and wind speed are both determinants in atmospheric dust concentration. Observations of atmospheric dust concentrations in Green Valley, AZ, USA, and Juárez, Chihuahua, México, show that PM10 concentrations are not directly correlated with wind speed or relative humidity separately. However, selecting the data for high wind speeds (>4m/s at 10 m elevation), a definite trend is observed between dust concentration and relative humidity: dust concentration increases with relative humidity, reaching a maximum around 25% and it subsequently decreases with relative humidity. Models for dust storm forecasting may be improved by utilizing atmospheric humidity and wind speed as main drivers for dust generation and transport. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Thermal comfort of people in the hot and humid area of China-impacts of season, climate, and thermal history.

    Science.gov (United States)

    Zhang, Y; Chen, H; Wang, J; Meng, Q

    2016-10-01

    We conducted a climate chamber study on the thermal comfort of people in the hot and humid area of China. Sixty subjects from naturally ventilated buildings and buildings with split air conditioners participated in the study, and identical experiments were conducted in a climate chamber in both summer and winter. Psychological and physiological responses were observed over a wide range of conditions, and the impacts of season, climate, and thermal history on human thermal comfort were analyzed. Seasonal and climatic heat acclimatization was confirmed, but they were found to have no significant impacts on human thermal sensation and comfort. The outdoor thermal history was much less important than the indoor thermal history in regard to human thermal sensation, and the indoor thermal history in all seasons of a year played a key role in shaping the subjects' sensations in a wide range of thermal conditions. A warmer indoor thermal history in warm seasons produced a higher neutral temperature, a lower thermal sensitivity, and lower thermal sensations in warm conditions. The comfort and acceptable conditions were identified for people in the hot and humid area of China. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Evaluation of the Performance of Houses With and Without Supplemental Dehumidification in a Hot-Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Kerrigan, P. [Building Science Corporation, Westford, MA (United States)

    2014-10-01

    This report describes a research study that was conducted by the Building Science Corporation (BSC) Building America Research Team. BSC seeks to research and report on the field monitoring of the performance of in-situ supplemental dehumidification systems in low energy, high performance homes in a hot-humid climate. The purpose of this research project was to observe and compare the humidity control performance. Specifically, the study sought to compare the interior conditions and mechanical systems operation between two distinct groups of houses; homes with a supplemental dehumidifier installed in addition to HVAC system, and homes without any supplemental dehumidification. The subjects of the study were 10 single-family, new construction homes in New Orleans, LA.

  10. The role of clothing in thermal comfort: how people dress in a temperate and humid climate in Brazil

    Directory of Open Access Journals (Sweden)

    Renata De Vecchi

    Full Text Available Abstract Thermal insulation from clothing is one of the most important input variables used to predict the thermal comfort of a building's occupants. This paper investigates the clothing pattern in buildings with different configurations located in a temperate and humid climate in Brazil. Occupants of two kinds of buildings (three offices and two university classrooms assessed their thermal environment through 'right-here-right-now' questionnaires, while at the same time indoor climatic measurements were carried out in situ (air temperature and radiant temperature, air speed and humidity. A total of 5,036 votes from 1,161 occupants were collected. Results suggest that the clothing values adopted by occupants inside buildings were influenced by: 1 climate and seasons of the year; 2 different configurations and indoor thermal conditions; and 3 occupants' age and gender. Significant intergenerational and gender differences were found, which might be explained by differences in metabolic rates and fashion. The results also indicate that there is a great opportunity to exceed the clothing interval of the thermal comfort zones proposed by international standards such as ASHRAE 55 (2013 - 0.5 to 1.0 clo - and thereby save energy from cooling and heating systems, without compromising the occupants' indoor thermal comfort.

  11. Building a 40% Energy Saving House in the Mixed-Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Christian, Jeffrey E [ORNL; Bonar, Jacob [ORNL

    2011-10-01

    This report describes a home that uses 40% less energy than the energy-efficient Building America standard - a giant step in the pursuit of affordable near-zero-energy housing through the evolution of five near-zero-energy research houses. This four-bedroom, two-bath, 1232-ft2 house has a Home Energy Rating System (HERS) index of 35 (a HERS rating of 0 is a zero-energy house, a conventional new house would have a HERS rating of 100), which qualifies it for federal energy efficiency and solar incentives. The house is leading to the planned construction of a similar home in Greensburg, Kansas, and 21 staff houses in the Walden Reserve, a 7000-unit "deep green" community in Cookville, Tennessee. Discussions are underway for construction of similar houses in Charleston, South Carolina, Seattle, Washington, Knoxville and Oak Ridge, Tennessee, and upstate New York. This house should lead to a 40% and 50% Gate-3, Mixed-Humid-Climate Joule for the DOE Building America Program. The house is constructed with structurally-insulated-panel walls and roof, raised metal-seam roof with infrared reflective coating, airtight envelope (1.65 air changes per hour at 50 Pascal), supply mechanical ventilation, ducts inside the conditioned space, extensive moisture control package, foundation geothermal space heating and cooling system, ZEHcor wall, solar water heater, and a 2.2 kWp grid-connected photovoltaic (PV) system. The detailed specifications for the envelope and the equipment used in ZEH5 compared to all the houses in this series are shown in Tables 1 and 2. Based on a validated computer simulation of ZEH5 with typical occupancy patterns and energy services for four occupants, energy for this all-electric house is predicted to cost only $0.66/day ($0.86/day counting the hookup charges). By contrast, the benchmark house would require $3.56/day, including hookup charges (these costs are based on a 2006 residential rates of $0.07/kWh and solar buyback at $0.15/kWh). The solar

  12. Moisture Performance of Energy-Efficient and Conventional Wood-Frame Wall Assemblies in a Mixed-Humid Climate

    Directory of Open Access Journals (Sweden)

    Samuel V. Glass

    2015-07-01

    Full Text Available Long-term moisture performance is a critical consideration for design and construction of building envelopes in energy-efficient buildings, yet field measurements of moisture characteristics for highly insulated wood-frame walls in mixed-humid climates are lacking. Temperature, relative humidity, and moisture content of wood framing and oriented strand board (OSB structural panel sheathing were measured over a period from mid-November 2011 through March 2013 in both north- and south-facing orientations in test structures near Washington, DC, USA. Wall configurations varied in exterior cladding, water-resistive barrier, level of cavity insulation, presence of exterior continuous insulation, and interior vapor retarder. The combination of high interior humidity and high vapor permeance of painted gypsum board led to significant moisture accumulation in OSB sheathing during winter in walls without a vapor retarder. In contrast, wintertime moisture accumulation was not significant with an interior kraft vapor retarder. Extruded polystyrene exterior insulation had a predictable effect on wall cavity temperature but a marginal impact on OSB moisture content in walls with vinyl siding and interior kraft vapor retarder. Hygrothermal simulations approximately captured the timing of seasonal changes in OSB moisture content, differences between north- and south-facing walls, and differences between walls with and without an interior kraft vapor retarder.

  13. Assessment of Humidity Conditions and Trends Based on Standardized Precipitation Evapotranspiration Index (SEPI Over Different Climatic Regions of Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Ghabaei S

    2017-01-01

    Full Text Available Introduction: Drought is a recurrent feature of climate that caused by deficiency of precipitation over time. Due to the rise in water demand and alarming climate change, recent year’s observer much focus on drought and drought conditions. A multiple types of deficits and relevant temporal scales can be achieved through the construction of a joint indicator that draws on information from multiple sources and will therefore enable better assessment of drought characteristics including return period, persistent and severity. The Standardized Precipitation Evapotranspiration Index (SPEI combines information from precipitation and temperature in the form of water surplus or deficit according to Standardized Precipitation Index (SPI. Rainfall over some regions of Iran during some resent year was below average while mean and maximum temperatures were very high during this period, as was evaporation. This would suggest that drought conditions were worse than in previous recent periods with similarly low rainfall. The main objective of this study is to assess the influences of humidity on the SPEI index and investigate its relation with SPI and Reconnaissance Drought Index (RDI over six different climatic regions in Iran. Materials and Methods: Iran has different climatic conditions which vary from desert in central part to costal wet near the Caspian Sea. In this study the selection of stations was done based on Alijani et al (2008 climatic classification. We chose 11 synoptic stations from six different climatic classes including costal wet (Rasht and Babolsar, semi mountains (Mashhad and Tabriz, mountains (Shiraz and Khoram Abad, semi-arid (Tehran and Semnan, arid (Kerman and Yazd and costal desert (Bandar Abas. The Meteorological datasets for the aforementioned stations were obtained from the Iran Meteorological Organization (IRIMO for the period 1960-2010. The compiled data included average monthly values of precipitation, minimum and maximum air

  14. Effects of acute supplementation of caffeine on cardiorespiratory responses during endurance running in a hot & humid climate.

    Science.gov (United States)

    Ping, Wong Chee; Keong, Chen Chee; Bandyopadhyay, Amit

    2010-07-01

    Athletes in Malaysia need to perform in a hot and humid climate. Chronic supplementation of caffeine on endurance performance have been studied extensively in different populations. However, concurrent research on the effects of acute supplementation of caffeine on cardiorespiratory responses during endurance exercise in the Malaysian context especially in a hot and humid environment is unavailable. Nine heat adapted recreational Malaysian male runners (aged: 25.4+/-6.9 yr) who were nonusers of caffeine (23.7+/-12.6 mg per day) were recruited in this placebo--controlled double--blind randomized study. Caffeine (5 mg per kg of body weight) or placebo was ingested in the form of a capsule one hour prior to the running exercise trial at 70 per cent of VO2max on a motorised treadmill in a heat-controlled laboratory (31 degrees C, 70% relative humidity). Subjects drank 3 ml of cool water per kg of body weight every 20 min during the running trials to avoid the adverse effects of dehydration. Heart rate, core body temperature and rate of perceived exertion (RPE) were recorded at intervals of 10 min, while oxygen consumption was measured at intervals of 20 min. Running time to exhaustion was significantly (Pexercise from their respective resting values in both trials (P<0.001). Our study showed that ingestion of 5 mg of caffeine per kg of body weight improved the endurance running performance but did not impose any significant effect on other individual cardiorespiratory parameters of heat-acclimated recreational runners in hot and humid conditions.

  15. Thermal comfort in air-conditioned buildings in hot and humid climates--why are we not getting it right?

    Science.gov (United States)

    Sekhar, S C

    2016-02-01

    While there are plenty of anecdotal experiences of overcooled buildings in summer, evidence from field studies suggests that there is indeed an issue of overcooling in tropical buildings. The findings suggest that overcooled buildings are not a consequence of occupant preference but more like an outcome of the HVAC system design and operation. Occupants' adaptation in overcooled indoor environments through additional clothing cannot be regarded as an effective mitigating strategy for cold thermal discomfort. In the last two decades or so, several field studies and field environmental chamber studies in the tropics provided evidence for occupants' preference for a warmer temperature with adaptation methods such as elevated air speeds. It is important to bear in mind that indoor humidity levels are not compromised as they could have an impact on the inhaled air condition that could eventually affect perceived air quality. This review article has attempted to track significant developments in our understanding of the thermal comfort issues in air-conditioned office and educational buildings in hot and humid climates in the last 25 years, primarily on occupant preference for thermal comfort in such climates. The issue of overcooled buildings, by design intent or otherwise, is discussed in some detail. Finally, the article has explored some viable adaptive thermal comfort options that show considerable promise for not only improving thermal comfort in tropical buildings but are also energy efficient and could be seen as sustainable solutions. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Evaporative Cooler Use Influences Temporal Indoor Relative Humidity but Not Dust Mite Allergen Levels in Homes in a Semi-Arid Climate.

    Science.gov (United States)

    Johnston, James D; Tuttle, Steven C; Nelson, Morgan C; Bradshaw, Rebecca K; Hoybjerg, Taylor G; Johnson, Julene B; Kruman, Bryce A; Orton, Taylor S; Cook, Ryan B; Eggett, Dennis L; Weber, K Scott

    2016-01-01

    Concerns about energy consumption and climate change make residential evaporative coolers a popular alternative to central air conditioning in arid and semi-arid climates. However, evaporative coolers have been shown to significantly increase indoor relative humidity and dust mite allergen levels in some studies, while showing no association in other studies. Improved measurement of temporal fluctuations in indoor relative humidity may help identify factors that promote mite growth in homes in dry climates. Dust samples and continuous indoor relative humidity measurements were collected from homes with central air conditioning and homes with evaporative coolers in Utah. Samples were collected over two seasons, winter/spring (Jan-Apr) and summer (July-Sept), 2014. Dust samples were analyzed for Der p 1 and Der f 1 using a two-site monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA) analysis. Housing characteristics including age of home, occupant density, and age of mattresses, furniture, and carpeting were also measured. Positive Der p 1 or Der f 1 samples were found in 25.0% of the homes and there was no difference in mean allergen levels by type of air conditioning. Indoor relative humidity was significantly higher in homes with evaporative coolers compared to those with central air conditioning during the summer. Homes with evaporative coolers also spent significantly more time during summer above 55.0% and 65.0% relative humidity compared to central air homes, but not above 75.0%. Findings from this study suggest that increased humidity from evaporative coolers may not be sufficient to exceed the critical equilibrium humidity or maintain humidity excursions for sufficient duration in relatively larger single-family homes in semi-arid climates to support mite growth and reproduction.

  17. Evaporative Cooler Use Influences Temporal Indoor Relative Humidity but Not Dust Mite Allergen Levels in Homes in a Semi-Arid Climate.

    Directory of Open Access Journals (Sweden)

    James D Johnston

    Full Text Available Concerns about energy consumption and climate change make residential evaporative coolers a popular alternative to central air conditioning in arid and semi-arid climates. However, evaporative coolers have been shown to significantly increase indoor relative humidity and dust mite allergen levels in some studies, while showing no association in other studies. Improved measurement of temporal fluctuations in indoor relative humidity may help identify factors that promote mite growth in homes in dry climates. Dust samples and continuous indoor relative humidity measurements were collected from homes with central air conditioning and homes with evaporative coolers in Utah. Samples were collected over two seasons, winter/spring (Jan-Apr and summer (July-Sept, 2014. Dust samples were analyzed for Der p 1 and Der f 1 using a two-site monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA analysis. Housing characteristics including age of home, occupant density, and age of mattresses, furniture, and carpeting were also measured. Positive Der p 1 or Der f 1 samples were found in 25.0% of the homes and there was no difference in mean allergen levels by type of air conditioning. Indoor relative humidity was significantly higher in homes with evaporative coolers compared to those with central air conditioning during the summer. Homes with evaporative coolers also spent significantly more time during summer above 55.0% and 65.0% relative humidity compared to central air homes, but not above 75.0%. Findings from this study suggest that increased humidity from evaporative coolers may not be sufficient to exceed the critical equilibrium humidity or maintain humidity excursions for sufficient duration in relatively larger single-family homes in semi-arid climates to support mite growth and reproduction.

  18. Evaluation of skill at simulating heatwave and heat-humidity indices in Global and Regional Climate Models

    Science.gov (United States)

    Goldie, J. K.; Alexander, L. V.; Lewis, S. C.; Sherwood, S. C.

    2017-12-01

    A wide body of literature now establishes the harm of extreme heat on human health, and work is now emerging on the projection of future health impacts. However, heat-health relationships vary across different populations (Gasparrini et al. 2015), so accurate simulation of regional climate is an important component of joint health impact projection. Here, we evaluate the ability of nine Global Climate Models (GCMs) from CMIP5 and the NARCliM Regional Climate Model to reproduce a selection of 15 health-relevant heatwave and heat-humidity indices over the historical period (1990-2005) using the Perkins skill score (Perkins et al. 2007) in five Australian cities. We explore the reasons for poor model skill, comparing these modelled distributions to both weather station observations and gridded reanalysis data. Finally, we show changes in the modelled distributions from the highest-performing models under RCP4.5 and RCP8.5 greenhouse gas scenarios and discuss the implications of simulated heat stress for future climate change adaptation. ReferencesGasparrini, Antonio, Yuming Guo, Masahiro Hashizume, Eric Lavigne, Antonella Zanobetti, Joel Schwartz, Aurelio Tobias, et al. "Mortality Risk Attributable to High and Low Ambient Temperature: A Multicountry Observational Study." The Lancet 386, no. 9991 (July 31, 2015): 369-75. doi:10.1016/S0140-6736(14)62114-0. Perkins, S. E., A. J. Pitman, N. J. Holbrook, and J. McAneney. "Evaluation of the AR4 Climate Models' Simulated Daily Maximum Temperature, Minimum Temperature, and Precipitation over Australia Using Probability Density Functions." Journal of Climate 20, no. 17 (September 1, 2007): 4356-76. doi:10.1175/JCLI4253.1.

  19. Coherent Multidecadal Atmospheric and Oceanic Variability in the North Atlantic: Blocking Corresponds with Warm Subpolar Ocean

    Science.gov (United States)

    Hakkinen, Sirpa M.; Rhines, P. B.; Worthen, D. L.

    2012-01-01

    Winters with frequent atmospheric blocking, in a band of latitudes from Greenland to Western Europe, are found to persist over several decades and correspond to a warm North Atlantic Ocean. This is evident in atmospheric reanalysis data, both modern and for the full 20th century. Blocking is approximately in phase with Atlantic multidecadal ocean variability (AMV). Wintertime atmospheric blocking involves a highly distorted jetstream, isolating large regions of air from the westerly circulation. It influences the ocean through windstress-curl and associated air/sea heat flux. While blocking is a relatively high-frequency phenomenon, it is strongly modulated over decadal timescales. The blocked regime (weaker ocean gyres, weaker air-sea heat flux, paradoxically increased transport of warm subtropical waters poleward) contributes to the warm phase of AMV. Atmospheric blocking better describes the early 20thC warming and 1996-2010 warm period than does the NAO index. It has roots in the hemispheric circulation and jet stream dynamics. Subpolar Atlantic variability covaries with distant AMOC fields: both these connections may express the global influence of the subpolar North Atlantic ocean on the global climate system.

  20. HadISDH: an updateable land surface specific humidity product for climate monitoring

    Directory of Open Access Journals (Sweden)

    K. M. Willett

    2013-03-01

    Full Text Available HadISDH is a near-global land surface specific humidity monitoring product providing monthly means from 1973 onwards over large-scale grids. Presented herein to 2012, annual updates are anticipated. HadISDH is an update to the land component of HadCRUH, utilising the global high-resolution land surface station product HadISD as a basis. HadISD, in turn, uses an updated version of NOAA's Integrated Surface Database. Intensive automated quality control has been undertaken at the individual observation level, as part of HadISD processing. The data have been subsequently run through the pairwise homogenisation algorithm developed for NCDC's US Historical Climatology Network monthly temperature product. For the first time, uncertainty estimates are provided at the grid-box spatial scale and monthly timescale. HadISDH is in good agreement with existing land surface humidity products in periods of overlap, and with both land air and sea surface temperature estimates. Widespread moistening is shown over the 1973–2012 period. The largest moistening signals are over the tropics with drying over the subtropics, supporting other evidence of an intensified hydrological cycle over recent years. Moistening is detectable with high (95% confidence over large-scale averages for the globe, Northern Hemisphere and tropics, with trends of 0.089 (0.080 to 0.098 g kg−1 per decade, 0.086 (0.075 to 0.097 g kg−1 per decade and 0.133 (0.119 to 0.148 g kg−1 per decade, respectively. These changes are outside the uncertainty range for the large-scale average which is dominated by the spatial coverage component; station and grid-box sampling uncertainty is essentially negligible on large scales. A very small moistening (0.013 (−0.005 to 0.031 g kg−1 per decade is found in the Southern Hemisphere, but it is not significantly different from zero and uncertainty is large. When globally averaged, 1998 is the moistest year since monitoring began in 1973, closely

  1. Occupants’ Utilization of Natural Ventilation: A Study of Selected Terrace House Designs in Hot-humid Climate

    Directory of Open Access Journals (Sweden)

    Ibiyeye AI

    2015-05-01

    Full Text Available With increased time spent indoors and demand for enhanced comfort levels, energy consumption in homes is rising mostly for cooling, particularly in hot-humid regions. Natural ventilation is seen as an alternative to mechanical cooling as it is totally independent on energy and has been reported to be of high potential. However, little information is available on the utilization of natural ventilation in individual living spaces in different house designs. Therefore, this paper aims to investigate occupants’ utilization of natural ventilation in living spaces under different terrace house designs in hot-humid climate and also the relationship between the openings and occupants’ satisfaction with natural ventilation. Five (5 different terrace house types in Putrajaya, Malaysia with different opening design characteristics were selected for the study. A total of 298 households from these house types were surveyed and results show that occupants mostly open their windows during the daytime to capture breeze from outside despite the fact that they owned air-conditioners. In terms of occupants’ level of satisfaction with indoor ventilation when utilizing natural ventilation, majority rated neither satisfied nor unsatisfied. Further regression analysis reveals that this level of satisfaction is significantly related to opening sizes that are in accordance with the law, duration of opening windows and AC ownership. Findings from this study will shed more light on behavioural pattern of occupants of residential buildings towards natural ventilation provisions and highlight the importance of conforming to the law governing them.

  2. Irrigation water consumption modelling of a soilless cucumber crop under specific greenhouse conditions in a humid tropical climate

    Directory of Open Access Journals (Sweden)

    Galo Alberto Salcedo

    Full Text Available ABSTRACT: The irrigation water consumption of a soilless cucumber crop under greenhouse conditions in a humid tropical climate has been evaluated in this paper in order to improve the irrigation water and fertilizers management in these specific conditions. For this purpose, a field experiment was conducted. Two trials were carried out during the years 2011 and 2014 in an experimental farm located in Vinces (Ecuador. In each trial, the complete growing cycle of a cucumber crop grown under a greenhouse was evaluated. Crop development was monitored and a good fit to a sigmoidal Gompertz type growth function was reported. The daily water uptake of the crop was measured and related to the most relevant indoor climate variables. Two different combination methods, namely the Penman-Monteith equation and the Baille equation, were applied. However, the results obtained with these combination methods were not satisfactory due to the poor correlation between the climatic variables, especially the incoming radiation, and the crop's water uptake (WU. On contrary, a good correlation was reported between the crop's water uptake and the leaf area index (LAI, especially in the initial crop stages. However, when the crop is fully developed, the WU stabilizes and becomes independent from the LAI. A preliminary model to simulate the water uptake of the crop was adjusted using the data obtained in the first experiment and then validated with the data of the second experiment.

  3. Integrated and Optimized Energy-Efficient Construction Package for a Community of Production Homes in the Mixed-Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Mallay, D. [Partnership for Home Innovation, Upper Marlboro, MD (United States); Wiehagen, J. [Partnership for Home Innovation, Upper Marlboro, MD (United States); Del Bianco, M. [Partnership for Home Innovation, Upper Marlboro, MD (United States)

    2014-10-01

    This research high performance home analyzes how a set of advanced technologies can be integrated into a durable and energy-efficient house in the mixed-humid climate while remaining affordable to homeowners. The technical solutions documented in this report are the cornerstone of the builder's entire business model based on delivering high-performance homes on a production basis as a standard product offering to all price segments of the residential market. Home Innovation Research Labs partnered with production builder Nexus EnergyHomes (CZ 4) and they plan to adopt the successful components of the energy solution package for all 55 homes in the community. The research objective was to optimize the builder's energy solution package based on energy performance and construction costs. All of the major construction features, including envelope upgrades, space conditioning system, hot water system, and solar electric system were analyzed.

  4. Enhancement of stack ventilation in hot and humid climate using a combination of roof solar collector and vertical stack

    Energy Technology Data Exchange (ETDEWEB)

    Yusoff, Wardah Fatimah Mohammad; Salleh, Elias [Department of Architecture, Faculty of Design and Architecture, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Adam, Nor Mariah [Department of Mechanical and Manufacturing Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Sapian, Abdul Razak [Department of Architecture, Kulliyyah of Architecture and Environmental Design, International Islamic University Malaysia, P.O. Box 10, 50728 Kuala Lumpur (Malaysia); Yusof Sulaiman, Mohamad [Solar Energy Research Institute, 3rd Floor, Tun Sri Lanang Library Building, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2010-10-15

    In the hot and humid climate, stack ventilation is inefficient due to small temperature difference between the inside and outside of naturally ventilated buildings. Hence, solar induced ventilation is a feasible alternative in enhancing the stack ventilation. This paper aims to investigate the effectiveness of a proposed solar induced ventilation strategy, which combines a roof solar collector and a vertical stack, in enhancing the stack ventilation performance in the hot and humid climate. The methodology selected for the investigation is physical experimental modelling which was carried out in the actual environment. The results are presented and discussed in terms of two performance variables: air temperature and air velocity. The findings indicate that the proposed strategy is able to enhance the stack ventilation, both in semi-clear sky and overcast sky conditions. The highest air temperature difference between the air inside the stack and the ambient air (T{sub i}-T{sub o}) is achieved in the semi-clear sky condition, which is about 9.9 C (45.8 C-35.9 C). Meanwhile, in the overcast sky condition, the highest air temperature difference (T{sub i}-T{sub o}) is 6.2 C (39.3 C-33.1 C). The experimental results also indicate good agreement with the theoretical results for the glass temperature, the air temperature in the roof solar collector's channel and the absorber temperature. The findings also show that wind has significant effect to the induced air velocity by the proposed strategy. (author)

  5. A tool for design decision making - zero energy residential buildings in hot humid climates

    NARCIS (Netherlands)

    Attia, S.G.

    2012-01-01

    In this thesis, the development and evaluation of a simulation-based decision aid for Net Zero Energy Buildings (NZEBs) design, ZEBO, was explored. The thesis investigates the ability to achieve informed decision making for NZEB design, in hot climate. Four main questions were posed. Firstly, how to

  6. Simulation of the Holocene climate evolution in Nothern Africa: the termination of the African Humid Period.

    NARCIS (Netherlands)

    Renssen, H.; Brovkin, V.; Fichefet, T.; Goosse, H.

    2006-01-01

    The Holocene climate evolution in Northern Africa is studied in a 9000-yr-long transient simulation with a coupled atmosphere-ocean-vegetation model forced by changes in insolation and atmospheric greenhouse gas concentrations. The model simulates in the monsoonal domains a significant decrease in

  7. Climate-based statistical regression models for crop yield forecasting of coffee in humid tropical Kerala, India

    Science.gov (United States)

    Jayakumar, M.; Rajavel, M.; Surendran, U.

    2016-12-01

    A study on the variability of coffee yield of both Coffea arabica and Coffea canephora as influenced by climate parameters (rainfall (RF), maximum temperature (Tmax), minimum temperature (Tmin), and mean relative humidity (RH)) was undertaken at Regional Coffee Research Station, Chundale, Wayanad, Kerala State, India. The result on the coffee yield data of 30 years (1980 to 2009) revealed that the yield of coffee is fluctuating with the variations in climatic parameters. Among the species, productivity was higher for C. canephora coffee than C. arabica in most of the years. Maximum yield of C. canephora (2040 kg ha-1) was recorded in 2003-2004 and there was declining trend of yield noticed in the recent years. Similarly, the maximum yield of C. arabica (1745 kg ha-1) was recorded in 1988-1989 and decreased yield was noticed in the subsequent years till 1997-1998 due to year to year variability in climate. The highest correlation coefficient was found between the yield of C. arabica coffee and maximum temperature during January (0.7) and between C. arabica coffee yield and RH during July (0.4). Yield of C. canephora coffee had highest correlation with maximum temperature, RH and rainfall during February. Statistical regression model between selected climatic parameters and yield of C. arabica and C. canephora coffee was developed to forecast the yield of coffee in Wayanad district in Kerala. The model was validated for years 2010, 2011, and 2012 with the coffee yield data obtained during the years and the prediction was found to be good.

  8. Human thermal comfort conditions and urban planning in hot-humid climates-The case of Cuba.

    Science.gov (United States)

    Rodríguez Algeciras, José Abel; Coch, Helena; De la Paz Pérez, Guillermo; Chaos Yeras, Mabel; Matzarakis, Andreas

    2016-08-01

    Climate regional characteristics, urban environmental conditions, and outdoors thermal comfort requirements of residents are important for urban planning. Basic studies of urban microclimate can provide information and useful resources to predict and improve thermal conditions in hot-humid climatic regions. The paper analyzes the thermal bioclimate and its influence as urban design factor in Cuba, using Physiologically Equivalent Temperature (PET). Simulations of wind speed variations and shade conditions were performed to quantify changes in thermal bioclimate due to possible modifications in urban morphology. Climate data from Havana, Camagüey, and Santiago of Cuba for the period 2001 to 2012 were used to calculate PET with the RayMan model. The results show that changes in meteorological parameters influence the urban microclimate, and consequently modify the thermal conditions in outdoors spaces. Shade is the predominant strategy to improve urban microclimate with more significant benefits in terms of PET higher than 30 °C. For climatic regions such as the analyzed ones, human thermal comfort can be improved by a wind speed modification for thresholds of PET above 30 °C, and by a wind speed decreases in conditions below 26 °C. The improvement of human thermal conditions is crucial for urban sustainability. On this regards, our study is a contribution for urban designers, due to the possibility of taking advantage of results for improving microclimatic conditions based on urban forms. The results may enable urban planners to create spaces that people prefer to visit, and also are usable in the reconfiguration of cities.

  9. Interior shadings for office indoor visual comfort in humid climate region

    Science.gov (United States)

    Dinapradipta, Asri; Sudarma, Erwin; Defiana, Ima; Erwindi, Collinthia

    2018-03-01

    As part of the fenestration system, the interior shadings have also a role to control the indoor environment to maintain indoor visual comfort. As the occupants have personal access to control these, their control behavior then, might enhance or even worsen indoor comfort performance. The controlling behavior might not only influence indoor comfort performance but can also indicate the success or failure of interior shading as a control device element. This paper is intended to report control behavior patterns, as represented by the variety of the slats’ openings of two types of interior shading i.e. Venetian and Vertical blinds and to analyze these on the concurrent impacts to indoor office building’s indoor illuminance and luminance distribution. The purpose of this research is to figure out the shading control patterns as well as to examine the effectiveness of these two types of interior shadings to control indoor visual environment. This study is a quantitative research using experimentation on the slats’ opening of two types of shadings at two identical office rooms. The research results suggested that both types of blinds seem unsuitable for gaining proper illumination values at work planes in humid tropics area. However, these shadings demonstrate good performance for luminance distribution except for that of the closed Venetian blinds.

  10. Optimizing cloud removal from satellite remotely sensed data for monitoring vegetation dynamics in humid tropical climate

    International Nuclear Information System (INIS)

    Hashim, M; Pour, A B; Onn, C H

    2014-01-01

    Remote sensing technology is an important tool to analyze vegetation dynamics, quantifying vegetation fraction of Earth's agricultural and natural vegetation. In optical remote sensing analysis removing atmospheric interferences, particularly distribution of cloud contaminations, are always a critical task in the tropical climate. This paper suggests a fast and alternative approach to remove cloud and shadow contaminations for Landsat Enhanced Thematic Mapper + (ETM + ) multi temporal datasets. Band 3 and Band 4 from all the Landsat ETM + dataset are two main spectral bands that are very crucial in this study for cloud removal technique. The Normalise difference vegetation index (NDVI) and the normalised difference soil index (NDSI) are two main derivatives derived from the datasets. Change vector analysis is used in this study to seek the vegetation dynamics. The approach developed in this study for cloud optimizing can be broadly applicable for optical remote sensing satellite data, which are seriously obscured with heavy cloud contamination in the tropical climate

  11. Conceptual differences between the bioclimatic urbanism for Europe and for the tropical humid climate

    Energy Technology Data Exchange (ETDEWEB)

    Corbella, O.D.; Magalhaes, M.A.A.A. [Faculdade de Arquitetura e Urbanismo, Universidade Federal do Rio de Janeiro, Rio de Janeiro (Brazil)

    2008-05-15

    This article makes part of a series of conceptual papers to continue the discussion about how architecture and urbanism interact with climate, in tropical regions. Students engaged in normal courses of architecture in tropical regions, particularly in South America, develop their knowledge based on concepts generated in the developed countries - usually related to cold environments. Consequently, these students acquire wrong ideas about urban design of open spaces. Integrating urbanism and climate in tropical countries is still very incipient as an approach and many lecturers reject it, since they prefer to continue with a more formal one, dictated by most of the dominant countries. The herein paper underlines several different concepts and perspectives that separate the two conceptions, leading to a reflection about the subject. (author)

  12. Impacts of climate change on cropping patterns in a tropical, sub-humid watershed

    Science.gov (United States)

    Zwart, Sander J.; Hein, Lars

    2018-01-01

    In recent decades, there have been substantial increases in crop production in sub-Saharan Africa (SSA) as a result of higher yields, increased cropping intensity, expansion of irrigated cropping systems, and rainfed cropland expansion. Yet, to date much of the research focus of the impact of climate change on crop production in the coming decades has been on crop yield responses. In this study, we analyse the impact of climate change on the potential for increasing rainfed cropping intensity through sequential cropping and irrigation expansion in central Benin. Our approach combines hydrological modelling and scenario analysis involving two Representative Concentration Pathways (RCPs), two water-use scenarios for the watershed based on the Shared Socioeconomic Pathways (SSPs), and environmental water requirements leading to sustained streamflow. Our analyses show that in Benin, warmer temperatures will severely limit crop production increases achieved through the expansion of sequential cropping. Depending on the climate change scenario, between 50% and 95% of cultivated areas that can currently support sequential cropping or will need to revert to single cropping. The results also show that the irrigation potential of the watershed will be at least halved by mid-century in all scenario combinations. Given the urgent need to increase crop production to meet the demands of a growing population in SSA, our study outlines challenges and the need for planned development that need to be overcome to improve food security in the coming decades. PMID:29513753

  13. Overheating risk assessment of naturally ventilated classroom under the influence of climate change in hot and humid region

    Science.gov (United States)

    Huang, Kuo-Tsang

    2013-04-01

    Natural ventilation (NV) is considered one of the passive building strategies used for reducing cooling energy demand. The utilization of nature wind for cooling down indoor thermal environment to reach thermal comfort requires knowledge of adequately positioning the building fenestrations, designing inlet-outlet related opening ratios, planning unobstructed cross ventilation paths, and, the most important, assessing the utilization feasibility base on local climatic variables. Furthermore, factors that influence the indoor thermal condition include building envelope heat gain, indoor air velocity, indoor heat gain (e.g. heat discharges from occupant's body, lighting fixture, electrical appliances), and outdoor climate. Among the above, the indoor thermal performance of NV building is significantly dependent to outdoor climate conditions. In hot and humid Taiwan, under college school classrooms are usually operated in natural ventilation mode and are more vulnerable to climate change in regard to maintain indoor thermal comfort. As climate changes in progress, NV classrooms would expect to encounter more events of overheating in the near future, which result in more severe heat stress, and would risk the utilization of natural ventilation. To evaluate the overheating risk under the influence of recent climate change, an actual top floor elementary school classroom with 30 students located at north Taiwan was modeled. Long-term local hourly meteorological data were gathered and further constructed into EnergyPlus Weather Files (EPWs) format for building thermal dynamic simulation to discuss the indoor thermal environmental variation during the period of 1998 to 2012 by retrospective simulation. As indoor thermal environment is an overall condition resulting from a series combination of various factors, sub-hourly building simulation tool, EnergyPlus, coupled with the above fifteen years' EPWs was adopted to predict hourly indoor parameters of mean radiant

  14. Can thermal perception in a building be predicted by the perceived spatial openness of a building in a hot and humid climate?

    NARCIS (Netherlands)

    Du, X.; Bokel, R.M.J.; van den Dobbelsteen, A.A.J.F.; Brotas, Luisa; Roaf, Susan; Nicol, Fergus

    2017-01-01

    The authors wanted to prove that there is a large correlation between the concepts spatial openness and comfort (visual, wind speed and thermal) perception in people’s minds in a hot and humid climate in summer in order to be able to use spatial configuration parameters such as openness,

  15. Assessment of tracheal temperature and humidity in laryngectomized individuals and the influence of a heat and moisture exchanger on tracheal climate

    NARCIS (Netherlands)

    Zuur, J. Karel; Muller, Saar H.; Vincent, Andrew; Sinaasappel, Michiel; de Jongh, Frans H. C.; Hilgers, Frans J. M.

    2008-01-01

    The beneficial function of heat and moisture exchangers (HMEs) is undisputed, but knowledge of their effects on intra-airway temperature and humidity is scarce. The aim of this study was to evaluate the clinical applicability of a new airway climate explorer (ACE) and to assess the HME's influence

  16. Building America Best Practices Series: Volume 1; Builders and Buyers Handbook for Improving New Home Efficiency, Comfort, and Durability in the Hot and Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    None

    2004-12-01

    This Building America Best Practices guide book is a resource to help builders large and small build high-quality, energy-efficient homes that achieve 30% energy savings in space conditioning and water heating in the hot and humid climate.

  17. Vegetation Responses to Climate Variability in the Northern Arid to Sub-Humid Zones of Sub-Saharan Africa

    Directory of Open Access Journals (Sweden)

    Khaldoun Rishmawi

    2016-11-01

    Full Text Available In water limited environments precipitation is often considered the key factor influencing vegetation growth and rates of development. However; other climate variables including temperature; humidity; the frequency and intensity of precipitation events are also known to affect productivity; either directly by changing photosynthesis and transpiration rates or indirectly by influencing water availability and plant physiology. The aim here is to quantify the spatiotemporal patterns of vegetation responses to precipitation and to additional; relevant; meteorological variables. First; an empirical; statistical analysis of the relationship between precipitation and the additional meteorological variables and a proxy of vegetation productivity (the Normalized Difference Vegetation Index; NDVI is reported and; second; a process-oriented modeling approach to explore the hydrologic and biophysical mechanisms to which the significant empirical relationships might be attributed. The analysis was conducted in Sub-Saharan Africa; between 5 and 18°N; for a 25-year period 1982–2006; and used a new quasi-daily Advanced Very High Resolution Radiometer (AVHRR dataset. The results suggest that vegetation; particularly in the wetter areas; does not always respond directly and proportionately to precipitation variation; either because of the non-linearity of soil moisture recharge in response to increases in precipitation; or because variations in temperature and humidity attenuate the vegetation responses to changes in water availability. We also find that productivity; independent of changes in total precipitation; is responsive to intra-annual precipitation variation. A significant consequence is that the degree of correlation of all the meteorological variables with productivity varies geographically; so no one formulation is adequate for the entire region. Put together; these results demonstrate that vegetation responses to meteorological variation are more

  18. Quantifying wetland–aquifer interactions in a humid subtropical climate region: An integrated approach

    Science.gov (United States)

    Mendoza-Sanchez, Itza; Phanikumar, Mantha S.; Niu, Jie; Masoner, Jason R.; Cozzarelli, Isabelle M.; McGuire, Jennifer T.

    2013-01-01

    Wetlands are widely recognized as sentinels of global climate change. Long-term monitoring data combined with process-based modeling has the potential to shed light on key processes and how they change over time. This paper reports the development and application of a simple water balance model based on long-term climate, soil, vegetation and hydrological dynamics to quantify groundwater–surface water (GW–SW) interactions at the Norman landfill research site in Oklahoma, USA. Our integrated approach involved model evaluation by means of the following independent measurements: (a) groundwater inflow calculation using stable isotopes of oxygen and hydrogen (16O, 18O, 1H, 2H); (b) seepage flux measurements in the wetland hyporheic sediment; and (c) pan evaporation measurements on land and in the wetland. The integrated approach was useful for identifying the dominant hydrological processes at the site, including recharge and subsurface flows. Simulated recharge compared well with estimates obtained using isotope methods from previous studies and allowed us to identify specific annual signatures of this important process during the period of study (1997–2007). Similarly, observations of groundwater inflow and outflow rates to and from the wetland using seepage meters and isotope methods were found to be in good agreement with simulation results. Results indicate that subsurface flow components in the system are seasonal and readily respond to rainfall events. The wetland water balance is dominated by local groundwater inputs and regional groundwater flow contributes little to the overall water balance.

  19. Analyses of phase change materials’ efficiency in warm-summer humid continental climate conditions

    Science.gov (United States)

    Ratnieks, J.; Gendelis, S.; Jakovics, A.; Bajare, D.

    2017-10-01

    The usage of phase change materials (PCMs) is a way to store excess energy produced during the hot time of the day and release it during the night thereby reducing the overheating problem. While, in Latvian climate conditions overheating is not a big issue in traditional buildings since it happens only a couple of weeks per year air conditioners must still be installed to maintain thermal comfort. The need for cooling in recently built office buildings with large window area can increase significantly. It is therefore of great interest if the thermal comfort conditions can be maintained by PCMs alone or with reduced maximum power of installed cooling systems. Our initial studies show that if the test building is well-insulated (necessary to reduce heat loss in winter), phase change material is not able to solidify fast enough during the relatively short night time. To further investigate the problem various experimental setups with two different phase change materials were installed in test buildings. Experimental results are compared with numerical modelling made in software COMSOL Multiphysics. The effectiveness of PCM using different situations is widely analysed.

  20. Integrated and Optimized Energy-Efficient Construction Package for a Community of Production Homes in the Mixed-Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Mallay, D.; Wiehagen, J.; Del Bianco, M.

    2014-10-01

    Selection and integration of high performance home features are two sides of the same coin in energy efficient sustainable construction. Many advanced technologies are available for selection, but it is in the integration of these technologies into an affordable set of features that can be used on a production basis by builders, that ensures whole-house performance meets expectations. This research high performance home analyzes how a set of advanced technologies can be integrated into a durable and energy efficient house in the mixed-humid climate while remaining affordable to homeowners. The technical solutions documented in this report are the cornerstone of the builder's entire business model based on delivering high-performance homes on a production basis as a standard product offering to all price segments of the residential market. Home Innovation Research Labs partnered with production builder Nexus EnergyHomes (CZ 4). The builder plans to adopt the successful components of the energy solution package for all 55 homes in the community. The research objective was to optimize the builder's energy solution package based on energy performance and construction costs. All of the major construction features, including envelope upgrades, space conditioning system, hot water system, and solar electric system were analyzed. The information in this report can be used by builders and designers to evaluate options, and the integration of options, for increasing the efficiency of home designs in climate zone 4. The data also provide a point of reference for evaluating estimates of energy savings and costs for specific features.

  1. Late Pliocene diversity and distribution of Drynaria (Polypodiaceae in western Yunnan explained by forest vegetation and humid climates

    Directory of Open Access Journals (Sweden)

    Yong-Jiang Huang

    2016-08-01

    Full Text Available The palaeodiversity of flowering plants in Yunnan has been extensively interpreted from both a molecular and fossil perspective. However, for cryptogamic plants such as ferns, the palaeodiversity remains poorly known. In this study, we describe a new ferny fossil taxon, Drynaria lanpingensis sp. nov. Huang, Su et Zhou (Polypodiaceae, from the late Pliocene of northwestern Yunnan based on fragmentary frond and pinna with in situ spores. The frond is pinnatifid and the pinnae are entirely margined. The sori are arranged in one row on each side of the primary vein. The spores have a semicircular to bean-shaped equatorial view and a tuberculate surface. Taken together with previously described fossils, there are now representatives of three known fossil taxa of Drynaria from the late Pliocene of western Yunnan. These finds suggest that Drynaria diversity was considerable in the region at that time. As Drynaria is a shade-tolerant plant, growing preferably in wet conditions in the understory of forests, its extensive existence may indicate forest vegetation and humid climates in western Yunnan during the late Pliocene. This is in line with results from floristic investigations and palaeoclimatic reconstructions based on fossil floras.

  2. Performance Verification of Production-Scalable Energy-Efficient Solutions: Winchester/Camberley Homes Mixed-Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Mallay, D. [Partnership for Home Innovation, Upper Marlboro, MD (United States); Wiehagen, J. [Partnership for Home Innovation, Upper Marlboro, MD (United States)

    2014-07-01

    Winchester/Camberley Homes collaborated with the Building America team Partnership for Home Innovation to develop a new set of high performance home designs that could be applicable on a production scale. The new home designs are to be constructed in the mixed humid climate zone and could eventually apply to all of the builder's home designs to meet or exceed future energy codes or performance-based programs. However, the builder recognized that the combination of new wall framing designs and materials, higher levels of insulation in the wall cavity, and more detailed air sealing to achieve lower infiltration rates changes the moisture characteristics of the wall system. In order to ensure long term durability and repeatable successful implementation with few call-backs, the project team demonstrated through measured data that the wall system functions as a dynamic system, responding to changing interior and outdoor environmental conditions within recognized limits of the materials that make up the wall system. A similar investigation was made with respect to the complete redesign of the HVAC systems to significantly improve efficiency while maintaining indoor comfort. Recognizing the need to demonstrate the benefits of these efficiency features, the builder offered a new house model to serve as a test case to develop framing designs, evaluate material selections and installation requirements, changes to work scopes and contractor learning curves, as well as to compare theoretical performance characteristics with measured results.

  3. Performance Verification of Production-Scalable Energy-Efficient Solutions: Winchester/Camberley Homes Mixed-Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Mallay, D.; Wiehagen, J.

    2014-07-01

    Winchester/Camberley Homes with the Building America program and its NAHB Research Center Industry Partnership collaborated to develop a new set of high performance home designs that could be applicable on a production scale. The new home designs are to be constructed in the mixed humid climate zone four and could eventually apply to all of the builder's home designs to meet or exceed future energy codes or performance-based programs. However, the builder recognized that the combination of new wall framing designs and materials, higher levels of insulation in the wall cavity, and more detailed air sealing to achieve lower infiltration rates changes the moisture characteristics of the wall system. In order to ensure long term durability and repeatable successful implementation with few call-backs, this report demonstrates through measured data that the wall system functions as a dynamic system, responding to changing interior and outdoor environmental conditions within recognized limits of the materials that make up the wall system. A similar investigation was made with respect to the complete redesign of the heating, cooling, air distribution, and ventilation systems intended to optimize the equipment size and configuration to significantly improve efficiency while maintaining indoor comfort. Recognizing the need to demonstrate the benefits of these efficiency features, the builder offered a new house model to serve as a test case to develop framing designs, evaluate material selections and installation requirements, changes to work scopes and contractor learning curves, as well as to compare theoretical performance characteristics with measured results.

  4. Building America Case Study: Compact Buried Ducts in a Hot-Humid Climate House, Lady's Island, South Carolina

    Energy Technology Data Exchange (ETDEWEB)

    2016-02-01

    A system of compact, buried ducts provides a high-performance and cost-effective solution for delivering conditioned air throughout the building. This report outlines research activities that are expected to facilitate adoption of compact buried duct systems by builders. The results of this research would be scalable to many new house designs in most climates and markets, leading to wider industry acceptance and building code and energy program approval. The primary research question with buried ducts is potential condensation at the outer jacket of the duct insulation in humid climates during the cooling season. Current best practices for buried ducts rely on encapsulating the insulated ducts with closed-cell spray polyurethane foam insulation to control condensation and improve air sealing. The encapsulated buried duct concept has been analyzed and shown to be effective in hot-humid climates. The purpose of this project is to develop an alternative buried duct system that performs effectively as ducts in conditioned space - durable, energy efficient, and cost-effective - in a hot-humid climate (IECC warm-humid climate zone 3A) with three goals that distinguish this project: 1) Evaluation of design criteria for buried ducts that use common materials and do not rely on encapsulation using spray foam or disrupt traditional work sequences, 2) Establishing design criteria for compact ducts and incorporate those with the buried duct criteria to further reduce energy losses and control installed costs, and 3) Developing HVAC design guidance for performing accurate heating and cooling load calculations for compact buried ducts.

  5. Low Humidity Characteristics of Polymer-Based Capacitive Humidity Sensors

    OpenAIRE

    Majewski Jacek

    2017-01-01

    Polymer-based capacitive humidity sensors emerged around 40 years ago; nevertheless, they currently constitute large part of sensors’ market within a range of medium (climatic and industrial) humidity 20−80%RH due to their linearity, stability and cost-effectiveness. However, for low humidity values (0−20%RH) that type of sensor exhibits increasingly nonlinear characteristics with decreasing of humidity values. This paper presents the results of some experimental trials of CMOS polymer-based ...

  6. Surface Buoyancy Fluxes and the Strength of the Subpolar Gyre

    Science.gov (United States)

    Hogg, A. M.; Gayen, B.

    2017-12-01

    Midlatitude ocean gyres have long been considered to be driven by the mechanical wind stress on the ocean's surface (strictly speaking, the potential vorticity input from wind stress curl). However, surface buoyancy forcing (i.e. heating/cooling or freshening/salinification) also modifies the potential vorticity at the surface. Here, we present a simple argument to demonstrate that ocean gyres may (in principle) be driven by surface buoyancy forcing. This argument is derived in two ways: A Direct Numerical Simulation, driven purely by buoyancy forcing, which generates strong nonlinear gyers in the absence of wind stress; and A series of idealised eddy-resolving numerical ocean model simulations, in which wind stress and buoyancy flux are varied independently and together, are used to understand the relative importance of these two types of forcing. In these simulations, basin-scale gyres and western boundary currents with realistic magnitudes, remain even in the absence of mechanical forcing by surface wind stress. These results support the notion that surface buoyancy forcing can reorganise the potential vorticity in the ocean in such a way as to drive basin-scale gyres. The role of buoyancy is stronger in the subpolar gyre than in the subtropical gyre. We infer that surface buoyancy fluxes are likely to play a contributing role in governing the strength, variability and predictability of the North Atlantic subpolar gyre.

  7. The triple oxygen isotope composition of phytoliths as a proxy of continental atmospheric humidity: insights from climate chamber and climate transect calibrations

    Directory of Open Access Journals (Sweden)

    A. Alexandre

    2018-05-01

    Full Text Available Continental atmospheric relative humidity (RH is a key climate parameter. Combined with atmospheric temperature, it allows us to estimate the concentration of atmospheric water vapor, which is one of the main components of the global water cycle and the most important gas contributing to the natural greenhouse effect. However, there is a lack of proxies suitable for reconstructing, in a quantitative way, past changes of continental atmospheric humidity. This reduces the possibility of making model–data comparisons necessary for the implementation of climate models. Over the past 10 years, analytical developments have enabled a few laboratories to reach sufficient precision for measuring the triple oxygen isotopes, expressed by the 17O-excess (17O-excess  =  ln (δ17O + 1 – 0.528  ×  ln (δ18O + 1, in water, water vapor and minerals. The 17O-excess represents an alternative to deuterium-excess for investigating relative humidity conditions that prevail during water evaporation. Phytoliths are micrometric amorphous silica particles that form continuously in living plants. Phytolith morphological assemblages from soils and sediments are commonly used as past vegetation and hydrous stress indicators. In the present study, we examine whether changes in atmospheric RH imprint the 17O-excess of phytoliths in a measurable way and whether this imprint offers a potential for reconstructing past RH. For that purpose, we first monitored the 17O-excess evolution of soil water, grass leaf water and grass phytoliths in response to changes in RH (from 40 to 100 % in a growth chamber experiment where transpiration reached a steady state. Decreasing RH from 80 to 40 % decreases the 17O-excess of phytoliths by 4.1 per meg/% as a result of kinetic fractionation of the leaf water subject to evaporation. In order to model with accuracy the triple oxygen isotope fractionation in play in plant water and in phytoliths we recommend direct and

  8. Initial stages of indoor atmospheric corrosion of electronics contact metals in humid tropical climate: tin and nickel

    Directory of Open Access Journals (Sweden)

    Veleva, L.

    2007-04-01

    Full Text Available Samples of electrolytic tin and nickel have been exposed for 1 to 12 m in indoor environment, inside a box (rain sheltered cabinet, placed in tropical humid marine-urban climate, as a part of Gulf of Mexico. The corrosion aggressiveness of box has been classified as a very high corrosive, based on the monitored chlorides and SO2 deposition rates, and the Temperature/Relative Humidity air daily complex. The annual mass increasing of nickel is approximately twice higher than its values of mass loss (C. The relation between nickel mass loss or increasing and time of wetness (t of metal surface is linear and does not obey the power equation C = A tn, which has be found for tin. The SEM images reveal a localized corrosion on nickel and tin surfaces. XRD detects the formation of SnCl2.H2O as a corrosion product. Within the time on the tin surface appear black spots, considered as organic material.

    Muestras de estaño y níquel electrolíticos han sido expuestas de 1 a 12 m en ambiente interno (indoor, en una caseta (gabinete protegido de lluvia, colocada en clima tropical húmedo marino-urbano del Golfo de México. La agresividad de la caseta ha sido clasificada como muy altamente corrosiva, basada al registro de la velocidad de deposición de cloruros y SO2, y en el complejo diario de temperatura/humedad relativa del aire. El incremento de masa anual de níquel es, aproximadamente, dos veces mayor que del valor de su pérdida de masa (C. La relación entre la pérdida de masa de Ni o su incremento, y el tiempo de humectación (t de la superficie metálica y lineal y no obedece la ley de potencia C = A tn , que ha sido encontrada para el estaño. Las imágenes del SEM revelan una corrosión localizada en las superficie de níquel y estaño. El análisis de rayos-X detecta la formación de SnCl2.H2O como producto de corrosión. Con el tiempo

  9. Hygroscopical behaviour of basic electrodes in a tropical humid climate. Comportamiento microscopico de ciertos electrodos revistidos de caracter basico en clima tropical humedo

    Energy Technology Data Exchange (ETDEWEB)

    Valencia, E.; Galeano, N.J.

    1993-01-01

    The study of the wetting kynetics of basic electrodes in a tropical humid climate is very important since the water contained in them is the main source for the atomic hydrogen absorbed by the fused metal during electric arc welding. It is also the origin of multiple defects in the added metal. A calculating method is established for evaluating the kynetics of wetness incorporation to the coating of basic electrodes exposed to a humid tropical climate. The method is based on the Fick's diffusion equation for both adequate system geometry and boundary conditions, which allows the evaluation of the effective diffusion coefficient and critical times of exposure to the different environments, along with the packing and storage conditions of electrodes. (Author)

  10. Hygroscopical behaviour of basic electrodes in a tropical humid climate. Comportamiento microscopico de ciertos electrodos revistidos de caracter basico en clima tropical humedo

    Energy Technology Data Exchange (ETDEWEB)

    Valencia, E; Galeano, N J

    1993-01-01

    The study of the wetting kynetics of basic electrodes in a tropical humid climate is very important since the water contained in them is the main source for the atomic hydrogen absorbed by the fused metal during electric arc welding. It is also the origin of multiple defects in the added metal. A calculating method is established for evaluating the kynetics of wetness incorporation to the coating of basic electrodes exposed to a humid tropical climate. The method is based on the Fick's diffusion equation for both adequate system geometry and boundary conditions, which allows the evaluation of the effective diffusion coefficient and critical times of exposure to the different environments, along with the packing and storage conditions of electrodes. (Author)

  11. Temperature and Humidity Profiles in the TqJoint Data Group of AIRS Version 6 Product for the Climate Model Evaluation

    Science.gov (United States)

    Ding, Feng; Fang, Fan; Hearty, Thomas J.; Theobald, Michael; Vollmer, Bruce; Lynnes, Christopher

    2014-01-01

    The Atmospheric Infrared Sounder (AIRS) mission is entering its 13th year of global observations of the atmospheric state, including temperature and humidity profiles, outgoing long-wave radiation, cloud properties, and trace gases. Thus AIRS data have been widely used, among other things, for short-term climate research and observational component for model evaluation. One instance is the fifth phase of the Coupled Model Intercomparison Project (CMIP5) which uses AIRS version 5 data in the climate model evaluation. The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) is the home of processing, archiving, and distribution services for data from the AIRS mission. The GES DISC, in collaboration with the AIRS Project, released data from the version 6 algorithm in early 2013. The new algorithm represents a significant improvement over previous versions in terms of greater stability, yield, and quality of products. The ongoing Earth System Grid for next generation climate model research project, a collaborative effort of GES DISC and NASA JPL, will bring temperature and humidity profiles from AIRS version 6. The AIRS version 6 product adds a new "TqJoint" data group, which contains data for a common set of observations across water vapor and temperature at all atmospheric levels and is suitable for climate process studies. How different may the monthly temperature and humidity profiles in "TqJoint" group be from the "Standard" group where temperature and water vapor are not always valid at the same time? This study aims to answer the question by comprehensively comparing the temperature and humidity profiles from the "TqJoint" group and the "Standard" group. The comparison includes mean differences at different levels globally and over land and ocean. We are also working on examining the sampling differences between the "TqJoint" and "Standard" group using MERRA data.

  12. Prediction of spatial patterns of collapsed pipes in loess-derived soils in a temperate humid climate using logistic regression

    Science.gov (United States)

    Verachtert, E.; Den Eeckhaut, M. Van; Poesen, J.; Govers, G.; Deckers, J.

    2011-07-01

    Soil piping (tunnel erosion) has been recognised as an important erosion process in collapsible loess-derived soils of temperate humid climates, which can cause collapse of the topsoil and formation of discontinuous gullies. Information about the spatial patterns of collapsed pipes and regional models describing these patterns is still limited. Therefore, this study aims at better understanding the factors controlling the spatial distribution and predicting pipe collapse. A dataset with parcels suffering from collapsed pipes (n = 560) and parcels without collapsed pipes was obtained through a regional survey in a 236 km² study area in the Flemish Ardennes (Belgium). Logistic regression was applied to find the best model describing the relationship between the presence/absence of a collapsed pipe and a set of independent explanatory variables (i.e. slope gradient, drainage area, distance-to-thalweg, curvature, aspect, soil type and lithology). Special attention was paid to the selection procedure of the grid cells without collapsed pipes. Apart from the first piping susceptibility map created by logistic regression modelling, a second map was made based on topographical thresholds of slope gradient and upslope drainage area. The logistic regression model allowed identification of the most important factors controlling pipe collapse. Pipes are much more likely to occur when a topographical threshold depending on both slope gradient and upslope area is exceeded in zones with a sufficient water supply (due to topographical convergence and/or the presence of a clay-rich lithology). On the other hand, the use of slope-area thresholds only results in reasonable predictions of piping susceptibility, with minimum information.

  13. Building America Best Practices Series Volume 15: 40% Whole-House Energy Savings in the Hot-Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Baechler, Michael C.; Gilbride, Theresa L.; Hefty, Marye G.; Cole, Pamala C.; Adams, Karen; Noonan, Christine F.

    2011-09-01

    This best practices guide is the 15th in a series of guides for builders produced by PNNL for the U.S. Department of Energy’s Building America program. This guide book is a resource to help builders design and construct homes that are among the most energy-efficient available, while addressing issues such as building durability, indoor air quality, and occupant health, safety, and comfort. With the measures described in this guide, builders in the hot-humid climate can build homes that have whole-house energy savings of 40% over the Building America benchmark with no added overall costs for consumers. The best practices described in this document are based on the results of research and demonstration projects conducted by Building America’s research teams. Building America brings together the nation’s leading building scientists with over 300 production builders to develop, test, and apply innovative, energy-efficient construction practices. Building America builders have found they can build homes that meet these aggressive energy-efficiency goals at no net increased costs to the homeowners. Currently, Building America homes achieve energy savings of 40% greater than the Building America benchmark home (a home built to mid-1990s building practices roughly equivalent to the 1993 Model Energy Code). The recommendations in this document meet or exceed the requirements of the 2009 IECC and 2009 IRC and those requirements are highlighted in the text. Requirements of the 2012 IECC and 2012 IRC are also noted in text and tables throughout the guide. This document will be distributed via the DOE Building America website: www.buildingamerica.gov.

  14. Building America Best Practices Series Volume 16: 40% Whole-House Energy Savings in the Mixed-Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Baechler, Michael C.; Gilbride, Theresa L.; Hefty, Marye G.; Cole, Pamala C.; Adams, Karen; Butner, Ryan S.; Ortiz, Sallie J.

    2011-09-01

    This best practices guide is the 16th in a series of guides for builders produced by PNNL for the U.S. Department of Energy’s Building America program. This guide book is a resource to help builders design and construct homes that are among the most energy-efficient available, while addressing issues such as building durability, indoor air quality, and occupant health, safety, and comfort. With the measures described in this guide, builders in the mixed-humid climate can build homes that have whole-house energy savings of 40% over the Building America benchmark with no added overall costs for consumers. The best practices described in this document are based on the results of research and demonstration projects conducted by Building America’s research teams. Building America brings together the nation’s leading building scientists with over 300 production builders to develop, test, and apply innovative, energy-efficient construction practices. Building America builders have found they can build homes that meet these aggressive energy-efficiency goals at no net increased costs to the homeowners. Currently, Building America homes achieve energy savings of 40% greater than the Building America benchmark home (a home built to mid-1990s building practices roughly equivalent to the 1993 Model Energy Code). The recommendations in this document meet or exceed the requirements of the 2009 IECC and 2009 IRC and those requirements are highlighted in the text. Requirements of the 2012 IECC and 2012 IRC are also noted in text and tables throughout the guide. This document will be distributed via the DOE Building America website: www.buildingamerica.gov.

  15. Salinity Trends within the Upper Layers of the Subpolar North Atlantic

    Science.gov (United States)

    Tesdal, J. E.; Abernathey, R.; Goes, J. I.; Gordon, A. L.; Haine, T. W. N.

    2017-12-01

    Examination of a range of salinity products collectively suggest widespread freshening of the North Atlantic from the mid-2000 to the present. Monthly salinity fields reveal negative trends that differ in magnitude and significance between western and eastern regions of the North Atlantic. These differences can be attributed to the large negative interannual excursions in salinity in the western subpolar gyre and the Labrador Sea, which are not apparent in the central or eastern subpolar gyre. This study demonstrates that temporal trends in salinity in the northwest (including the Labrador Sea) are subject to mechanisms that are distinct from those responsible for the salinity trends in central and eastern North Atlantic. In the western subpolar gyre a negative correlation between near surface salinity and the circulation strength of the subpolar gyre suggests that negative salinity anomalies are connected to an intensification of the subpolar gyre, which is causing increased flux of freshwater from the East Greenland Current and subsequent transport into the Labrador Sea during the melting season. Analyses of sea surface wind fields suggest that the strength of the subpolar gyre is linked to the North Atlantic Oscillation and Arctic Oscillation-driven changes in wind stress curl in the eastern subpolar gyre. If this trend of decreasing salinity continues, it has the potential to enhance water column stratification, reduce vertical fluxes of nutrients and cause a decline in biological production and carbon export in the North Atlantic Ocean.

  16. Performance of operational radiosonde humidity sensors in direct comparison with a chilled mirror dew-point hygrometer and its climate implication

    Science.gov (United States)

    Wang, Junhong; Carlson, David J.; Parsons, David B.; Hock, Terrence F.; Lauritsen, Dean; Cole, Harold L.; Beierle, Kathryn; Chamberlain, Edward

    2003-08-01

    This study evaluates performance of humidity sensors in two widely used operational radiosondes, Vaisala and Sippican (formally VIZ), in comparison with a research quality, and potentially more accurate, chilled mirror dew-point hygrometer named ``Snow White''. A research radiosonde system carrying the Snow White (SW) hygrometer was deployed in the Oklahoma panhandle and at Dodge City, KS during the International H2O Project (IHOP_2002). A total of sixteen sondes were launched with either Vaisala RS80 or Sippican VIZ-B2 radiosondes on the same balloons. Comparisons of humidity data from the SW with Vaisala and Sippican data show that (a) Vaisala RS80-H agrees with the SW very well in the middle and lower troposphere, but has dry biases in the upper troposphere (UT), (b) Sippican carbon hygristor (CH) has time-lag errors throughout the troposphere and fails to respond to humidity changes in the UT, sometimes even in the middle troposphere, and (c) the SW can detect cirrus clouds near the tropopause and possibly estimate their ice water content (IWC). The failure of CH in the UT results in significant and artificial humidity shifts in radiosonde climate records at stations where a transition from VIZ to Vaisala radiosondes has occurred.

  17. Phytoplankton bloom and subpolar gyre induced dynamics in the North Atlantic

    DEFF Research Database (Denmark)

    Ferreira, Ana Sofia; Hátún, H.; Counillon, F.

    Several hypotheses have been promoted for phytoplankton bloom onset in the North Atlantic. First we show that the bloom dynamics in the northeastern corner stand out from the rest of the subpolar Atlantic, and thus warrants focused attention. We hypothesized that, for this region, late and weak...... blooms are expected in years of a strong subpolar gyre, i.e. strong atmospheric forcing, and cold and low saline conditions. We apply novel phenology algorithms to satellite ocean colour data, and analyse the outcome together with the subpolar gyre index. We find that the relationship between the bloom...

  18. Impact of wind-driven rain on historic brick wall buildings in a moderately cold and humid climate: Numerical analyses of mould growth risk, indoor climate and energy consumption

    DEFF Research Database (Denmark)

    Masaru, Abuku; Janssen, Hans; Roels, Staf

    2009-01-01

    This paper gives an onset to whole building hygrothermal modelling in which the interaction between interior and exterior climates via building enclosures is simulated under a moderately cold and humid climate. The focus is particularly on the impact of wind-driven rain (WDR) oil the hygrothermal...... response, mould growth at interior wall surfaces, indoor climate and energy consumption. First the WDR load oil the facades of a 4 m x 4 m x 10 m tower is determined. Then the hygrothermal behaviour of the brick walls is analysed oil a horizontal slice through the tower. The simulations demonstrate...

  19. Analysis of Energy, Environmental and Life Cycle Cost Reduction Potential of Ground Source Heat Pump (GSHP) in Hot and Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Yong X. Tao; Yimin Zhu

    2012-04-26

    It has been widely recognized that the energy saving benefits of GSHP systems are best realized in the northern and central regions where heating needs are dominant or both heating and cooling loads are comparable. For hot and humid climate such as in the states of FL, LA, TX, southern AL, MS, GA, NC and SC, buildings have much larger cooling needs than heating needs. The Hybrid GSHP (HGSHP) systems therefore have been developed and installed in some locations of those states, which use additional heat sinks (such as cooling tower, domestic water heating systems) to reject excess heat. Despite the development of HGSHP the comprehensive analysis of their benefits and barriers for wide application has been limited and often yields non-conclusive results. In general, GSHP/HGSHP systems often have higher initial costs than conventional systems making short-term economics unattractive. Addressing these technical and financial barriers call for additional evaluation of innovative utility programs, incentives and delivery approaches. From scientific and technical point of view, the potential for wide applications of GSHP especially HGSHP in hot and humid climate is significant, especially towards building zero energy homes where the combined energy efficient GSHP and abundant solar energy production in hot climate can be an optimal solution. To address these challenges, this report presents gathering and analyzing data on the costs and benefits of GSHP/HGSHP systems utilized in southern states using a representative sample of building applications. The report outlines the detailed analysis to conclude that the application of GSHP in Florida (and hot and humid climate in general) shows a good potential.

  20. Multivariate analysis of effects of diurnal temperature and seasonal humidity variations by tropical savanna climate on the emissions of anthropogenic volatile organic compounds.

    Science.gov (United States)

    Liu, Chih-Chung; Chen, Wei-Hsiang; Yuan, Chung-Shin; Lin, Chitsan

    2014-02-01

    Volatile organic compounds (VOCs), particularly those from anthropogenic sources, have been of substantial concern. In this study, the influences of diurnal temperature and seasonal humidity variations by tropical savanna climate on the distributions of VOCs from stationary industrial sources were investigated by analyzing the concentrations during the daytime and nighttime in the dry and wet seasons and assessing the results by principal component analysis (PCA) and cluster analysis. Kaohsiung City in Southern Taiwan, known for its severe VOC pollution, was chosen as the location to be examined. In the results, the VOC concentrations were lower during the daytime and in the wet season, possibly attributed to the stronger photochemical reactions and increasing inhibition of VOC emissions and transports by elevating humidity levels. Certain compounds became appreciably more important at higher humidity, as these compounds were saturated hydrocarbons with relatively low molecular weights. The influence of diurnal temperature variation on VOC distribution behaviors seemed to be less important than and interacted with that of seasonal humidity variation. Heavier aromatic hydrocarbons with more complex structures and some aliphatic compounds were found to be the main species accounting for the maximum variances of the data observed at high humidity, and the distinct grouping of compounds implied a pronounced inherent characteristic of each cluster in the observed VOC distributions. Under the influence of diurnal temperature variation, selected VOCs that may have stronger photochemical resistances and/or longer lifetimes in the atmosphere were clustered with each other in the cluster analysis, whereas the other groups might consist of compounds with different levels of vulnerability to sunlight or high temperatures. These findings prove the complications in the current knowledge regarding the VOC contaminations and providing insight for managing the adverse impacts of

  1. Building America Best Practices Series: Volume 1; Builders and Buyers Handbook for Improving New Home Efficiency, Comfort, and Durability in the Hot and Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Baechler, M. C.; Love, P. M.

    2004-11-01

    This Building America Best Practices guide book is a resource to help builders large and small build high-quality, energy-efficient homes that achieve 30% energy savings in space conditioning and water heating in the hot and humid climate. The savings are in comparison with the 1993 Model Energy Code. The guide contains chapters for every member of the builder's team. There is also a chapter for homeowners on how to use the book to provide help in selecting a new home or builder.

  2. Building America Best Practices Series: Volume 4; Builders and Buyers Handbook for Improving New Home Efficiency, Comfort, and Durability in the Mixed-Humid Climate

    Energy Technology Data Exchange (ETDEWEB)

    Baechler, M. C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Taylor, Z. T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bartlett, R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gilbride, T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hefty, M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Steward, H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Love, P. M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Palmer, J. A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2005-09-01

    This best practices guide is part of a series produced by Building America. The guide book is a resource to help builders large and small build high-quality, energy-efficient homes that achieve 30% energy savings in space conditioning and water heating in the mixed-humid climate region. The savings are in comparison with the 1993 Model Energy Code. The guide contains chapters for every member of the builders team-from the manager to the site planner to the designers, site supervisors, the trades, and marketers. There is also a chapter for homeowners on how to use the book to provide help in selecting a new home or builder.

  3. Mechanisms underlying recent decadal changes in subpolar North Atlantic Ocean heat content

    Science.gov (United States)

    Piecuch, Christopher G.; Ponte, Rui M.; Little, Christopher M.; Buckley, Martha W.; Fukumori, Ichiro

    2017-09-01

    The subpolar North Atlantic (SPNA) is subject to strong decadal variability, with implications for surface climate and its predictability. In 2004-2005, SPNA decadal upper ocean and sea-surface temperature trends reversed from warming during 1994-2004 to cooling over 2005-2015. This recent decadal trend reversal in SPNA ocean heat content (OHC) is studied using a physically consistent, observationally constrained global ocean state estimate covering 1992-2015. The estimate's physical consistency facilitates quantitative causal attribution of ocean variations. Closed heat budget diagnostics reveal that the SPNA OHC trend reversal is the result of heat advection by midlatitude ocean circulation. Kinematic decompositions reveal that changes in the deep and intermediate vertical overturning circulation cannot account for the trend reversal, but rather ocean heat transports by horizontal gyre circulations render the primary contributions. The shift in horizontal gyre advection reflects anomalous circulation acting on the mean temperature gradients. Maximum covariance analysis (MCA) reveals strong covariation between the anomalous horizontal gyre circulation and variations in the local wind stress curl, suggestive of a Sverdrup response. Results have implications for decadal predictability.

  4. Importance of body-water circulation for body-heat dissipation in hot-humid climates: a distinctive body-water circulation in swamp buffaloes

    Directory of Open Access Journals (Sweden)

    S. Chanpongsang

    2010-02-01

    Full Text Available Thermo-regulation in swamp buffaloes has been investigated as an adaptive system to hot-humid climates, and several distinctive physiological responses were noted. When rectal temperature increased in hot conditions, blood volume, blood flow to the skin surface and skin temperature markedly increased in buffaloes relatively to cattle. On the other hand, the correlation between blood volume and plasma concentration of arginine vasopressin (AVP was compared between buffaloes and cattle under dehydration. Although plasma AVP in cattle increased immediately for reducing urine volume against a decrease in blood volume as well as the response observed in most animal species, the increase in plasma AVP was delayed in buffaloes, even after a large decrease in blood volume. In buffaloes, a marked increase in blood volume facilitated the dissipation of excess heat from the skin surface during wallowing. In addition, the change in plasma AVP observed in buffaloes was consistent with that of other animals living in habitats with the high availability of water. These results suggest that the thermo-regulatory system in buffaloes accelerates body-water circulation internally and externally. This system may be adaptive for heat dissipation in hot-humid climates, where an abundance of water is common.

  5. Applying Outdoor Environment to Develop Health, Comfort, and Energy Saving in the Office in Hot-Humid Climate

    Science.gov (United States)

    Chen, Rong; Sung, Wen-Pei; Chang, Hung-Chang; Chi, Yi-Rou

    2013-01-01

    A human life demand set to emerge in the future is the achievement of sustainability by maintaining a comfortable indoor environment without excessive reliance on energy-consuming air conditioners. The major research processes in this study are: (1) measuring indoor air quality and thermal comfort to evaluate the comfort of an indoor environment; (2) implementing questionnaire survey analysis to explore people's environmental self-perceptions and conducting a meta-analysis of the measurement results for air quality and physical aspects; and (3) constructing an indoor monitoring and management system. The experimental and analysis results of this research reveal that most of the office occupants preferred a cooler environment with a lower temperature. Additionally, because the summers in Taiwan are humid and hot, the occupants of an indoor space tend to feel uncomfortable because of the high humidity and poor indoor air quality. Therefore, Variable Air Volume (VAV), two air intakes, and exhaust plant are installed to improve indoor environment. After improvement, a lower temperature (approximately 21.2–23.9°C) indirectly reduces humidity, thereby making the occupants comfortable. Increasing air velocity to 0.1 ~ 0.15 m/s, the carbon dioxide concentrations decrease below the requirement of the WHO. Ninety-five percent of the workers corresponded to the standard comfort zone after this improvement. PMID:24311976

  6. Applying Outdoor Environment to Develop Health, Comfort, and Energy Saving in the Office in Hot-Humid Climate

    Directory of Open Access Journals (Sweden)

    Rong Chen

    2013-01-01

    Full Text Available A human life demand set to emerge in the future is the achievement of sustainability by maintaining a comfortable indoor environment without excessive reliance on energy-consuming air conditioners. The major research processes in this study are: (1 measuring indoor air quality and thermal comfort to evaluate the comfort of an indoor environment; (2 implementing questionnaire survey analysis to explore people’s environmental self-perceptions and conducting a meta-analysis of the measurement results for air quality and physical aspects; and (3 constructing an indoor monitoring and management system. The experimental and analysis results of this research reveal that most of the office occupants preferred a cooler environment with a lower temperature. Additionally, because the summers in Taiwan are humid and hot, the occupants of an indoor space tend to feel uncomfortable because of the high humidity and poor indoor air quality. Therefore, Variable Air Volume (VAV, two air intakes, and exhaust plant are installed to improve indoor environment. After improvement, a lower temperature (approximately 21.2–23.9°C indirectly reduces humidity, thereby making the occupants comfortable. Increasing air velocity to 0.1~0.15 m/s, the carbon dioxide concentrations decrease below the requirement of the WHO. Ninety-five percent of the workers corresponded to the standard comfort zone after this improvement.

  7. Influence of Courtyard Ventilation on Thermal Performance of Office Building in Hot-Humid Climate: A Case Study

    Science.gov (United States)

    Abbaas, Esra'a. Sh.; Saif, Ala'eddin A.; Munaaim, MAC; Azree Othuman Mydin, Md.

    2018-03-01

    The influence of courtyard on the thermal performance of Development Department office building in University Malaysia Perlis (UniMAP, Pauh Putra campus) is investigated through simulation study for the effect of ventilation on indoor air temperature and relative humidity of the building. The study is carried out using EnergyPlus simulator interface within OpenStudio and SketchUp plug in software to measure both of air temperature and relative humidity hourly on 21 April 2017 as a design day. The results show that the ventilation through the windows facing the courtyard has sufficient effect on reducing the air temperature compared to the ventilation through external windows since natural ventilation is highly effective on driving the indoor warm air out to courtyard. In addition, the relative humidity is reduced due to ventilation since the courtyard has high ability to remove or dilute indoor airborne pollutants coming from indoor sources. This indicates that the presence of courtyard is highly influential on thermal performance of the building.

  8. Health symptoms in relation to temperature, humidity, and self-reported perceptions of climate in New York City residential environments

    Science.gov (United States)

    Quinn, Ashlinn; Shaman, Jeffrey

    2017-07-01

    Little monitoring has been conducted of temperature and humidity inside homes despite the fact that these conditions may be relevant to health outcomes. Previous studies have observed associations between self-reported perceptions of the indoor environment and health. Here, we investigate associations between measured temperature and humidity, perceptions of indoor environmental conditions, and health symptoms in a sample of New York City apartments. We measured temperature and humidity in 40 New York City apartments during summer and winter seasons and collected survey data from the households' residents. Health outcomes of interest were (1) sleep quality, (2) symptoms of heat illness (summer season), and (3) symptoms of respiratory viral infection (winter season). Using mixed-effects logistic regression models, we investigated associations between the perceptions, symptoms, and measured conditions in each season. Perceptions of indoor temperature were significantly associated with measured temperature in both the summer and the winter, with a stronger association in the summer season. Sleep quality was inversely related to measured and perceived indoor temperature in the summer season only. Heat illness symptoms were associated with perceived, but not measured, temperature in the summer season. We did not find an association between any measured or perceived condition and cases of respiratory infection in the winter season. Although limited in size, the results of this study reveal that indoor temperature may impact sleep quality, and that thermal perceptions of the indoor environment may indicate vulnerability to heat illness. These are both important avenues for further investigation.

  9. Groundwater in the Boreal Plains: How Climate and Geology Interact to Control Water Table Configurations in a Sub-Humid, Low-Relief Region

    Science.gov (United States)

    Hokanson, K. J.; Devito, K.; Mendoza, C. A.

    2017-12-01

    The Boreal Plain (BP) region of Canada, a landscape characterized by low-relief, a sub-humid climate and heterogeneous glacial landforms, is experiencing unprecedented anthropogenic and natural disturbance, including climate change and oil & gas operations. Understanding the controls on and the natural variability of water table position, and subsequently predicting changes in water table position under varying physical and climatic scenarios will become important as water security becomes increasingly threatened. The BP is composed of a mosaic of forestland, wetland, and aquatic land covers that contrast in dominant vegetation cover, evapotranspiration, and soil storage that, in turn, influence water table configurations. Additionally, these land-covers overlie heterogeneous glacial landforms with large contrasts in storage and hydraulic properties which, when coupled with wet-dry climate cycles, result in complex water table distributions in time and space. Several forestland-wetland-pond complexes were selected at the Utikuma Research Study Area (URSA) over three distinct surficial geologic materials (glacial fluvial outwash, stagnant ice moraine, lacustrine clay plain) to explore the roles of climate (cumulative departure from the long term yearly mean precipitation), geology, topographic position, and land cover on water table configurations over 15 years (2002 - 2016). In the absence of large groundwater flow systems, local relief and shallow low conductivity substrates promote the formation of near-surface water tables that are less susceptible to climate variation, regardless of topography. Furthermore, in areas of increased storage, wet and dry climate conditions can result in appreciably different water table configurations over time, ranging from mounds to hydraulic depressions, depending on the arrangement of land-covers, dominant surficial geology, and substrate layering.

  10. Humidity and Buildings. Technical Paper No. 188.

    Science.gov (United States)

    Hutcheon, N. B.

    Modified and controlled relative humidity in buildings for certain occupancies is discussed. New criteria are used in determining the needs, desirability and problems associated with humidities in a building. Severe winter climate requires that special attention be given to the problems associated with increased indoor humidities during cold…

  11. EDITORIAL: Humidity sensors Humidity sensors

    Science.gov (United States)

    Regtien, Paul P. L.

    2012-01-01

    All matter is more or less hygroscopic. The moisture content varies with vapour concentration of the surrounding air and, as a consequence, most material properties change with humidity. Mechanical and thermal properties of many materials, such as the tensile strength of adhesives, stiffness of plastics, stoutness of building and packaging materials or the thermal resistivity of isolation materials, all decrease with increasing environmental humidity or cyclic humidity changes. The presence of water vapour may have a detrimental influence on many electrical constructions and systems exposed to humid air, from high-power systems to microcircuits. Water vapour penetrates through coatings, cable insulations and integrated-circuit packages, exerting a fatal influence on the performance of the enclosed systems. For these and many other applications, knowledge of the relationship between moisture content or humidity and material properties or system behaviour is indispensable. This requires hygrometers for process control or test and calibration chambers with high accuracy in the appropriate temperature and humidity range. Humidity measurement methods can roughly be categorized into four groups: water vapour removal (the mass before and after removal is measured); saturation (the air is brought to saturation and the `effort' to reach that state is measured); humidity-dependent parameters (measurement of properties of humid air with a known relation between a specific property and the vapour content, for instance the refractive index, electromagnetic spectrum and acoustic velocity); and absorption (based on the known relation between characteristic properties of non-hydrophobic materials and the amount of absorbed water from the gas to which these materials are exposed). The many basic principles to measure air humidity are described in, for instance, the extensive compilations by Wexler [1] and Sonntag [2]. Absorption-type hygrometers have small dimensions and can be

  12. A modelling study of the event-based retention performance of green roof under the hot-humid tropical climate in Kuching.

    Science.gov (United States)

    Chai, C T; Putuhena, F J; Selaman, O S

    2017-12-01

    The influences of climate on the retention capability of green roof have been widely discussed in existing literature. However, knowledge on how the retention capability of green roof is affected by the tropical climate is limited. This paper highlights the retention performance of the green roof situated in Kuching under hot-humid tropical climatic conditions. Using the green roof water balance modelling approach, this study simulated the hourly runoff generated from a virtual green roof from November 2012 to October 2013 based on past meteorological data. The result showed that the overall retention performance was satisfactory with a mean retention rate of 72.5% from 380 analysed rainfall events but reduced to 12.0% only for the events that potentially trigger the occurrence of flash flood. By performing the Spearman rank's correlation analysis, it was found that the rainfall depth and mean rainfall intensity, individually, had a strong negative correlation with event retention rate, suggesting that the retention rate increases with decreased rainfall depth. The expected direct relationship between retention rate and antecedent dry weather period was found to be event size dependent.

  13. Estimation of potential evapotranspiration from extraterrestrial radiation, air temperature and humidity to assess future climate change effects on the vegetation of the Northern Great Plains, USA

    Science.gov (United States)

    King, David A.; Bachelet, Dominique M.; Symstad, Amy J.; Ferschweiler, Ken; Hobbins, Michael

    2014-01-01

    The potential evapotranspiration (PET) that would occur with unlimited plant access to water is a central driver of simulated plant growth in many ecological models. PET is influenced by solar and longwave radiation, temperature, wind speed, and humidity, but it is often modeled as a function of temperature alone. This approach can cause biases in projections of future climate impacts in part because it confounds the effects of warming due to increased greenhouse gases with that which would be caused by increased radiation from the sun. We developed an algorithm for linking PET to extraterrestrial solar radiation (incoming top-of atmosphere solar radiation), as well as temperature and atmospheric water vapor pressure, and incorporated this algorithm into the dynamic global vegetation model MC1. We tested the new algorithm for the Northern Great Plains, USA, whose remaining grasslands are threatened by continuing woody encroachment. Both the new and the standard temperature-dependent MC1 algorithm adequately simulated current PET, as compared to the more rigorous PenPan model of Rotstayn et al. (2006). However, compared to the standard algorithm, the new algorithm projected a much more gradual increase in PET over the 21st century for three contrasting future climates. This difference led to lower simulated drought effects and hence greater woody encroachment with the new algorithm, illustrating the importance of more rigorous calculations of PET in ecological models dealing with climate change.

  14. An effect of humid climate on micro structure and chemical component of natural composite (Boehmeria nivea-Albizia falcata based wind turbine blade

    Directory of Open Access Journals (Sweden)

    Sudarsono S.

    2018-01-01

    Full Text Available In this work, wind turbine blade NACA 4415 is fabricated from natural composite of Boehmeria nivea and Albizia falcate. The composite fabrication method used is hand lay up method. The aim of the work is to investigate an effect of humid climate of coastal area on micro structure and chemical composition of composite material of the blade. The wind turbine is tested at Pantai Baru, Bantul, Yogyakarta for 5.5 months. The micro structure scanning is performed with Scanning Electron Microscope (SEM and material component is measured with Energy Dispersive X-ray spectrometer (EDS. The samples are tested before and after the use within 5.5 month at the location. The results show that composite material inexperienced interface degradation and insignificant change of micro structure. From EDS test, it is observed that Na filtration reduces C and increases O in composite material after 5.5 months.

  15. An effect of humid climate on micro structure and chemical component of natural composite (Boehmeria nivea-Albizia falcata) based wind turbine blade

    Science.gov (United States)

    Sudarsono, S.; Purwanto; Sudarsono, Johny W.

    2018-02-01

    In this work, wind turbine blade NACA 4415 is fabricated from natural composite of Boehmeria nivea and Albizia falcate. The composite fabrication method used is hand lay up method. The aim of the work is to investigate an effect of humid climate of coastal area on micro structure and chemical composition of composite material of the blade. The wind turbine is tested at Pantai Baru, Bantul, Yogyakarta for 5.5 months. The micro structure scanning is performed with Scanning Electron Microscope (SEM) and material component is measured with Energy Dispersive X-ray spectrometer (EDS). The samples are tested before and after the use within 5.5 month at the location. The results show that composite material inexperienced interface degradation and insignificant change of micro structure. From EDS test, it is observed that Na filtration reduces C and increases O in composite material after 5.5 months.

  16. It's the Heat AND the Humidity -- Assessment of Extreme Heat Scenarios to Enable the Assessment of Climate Impacts on Public Health

    Science.gov (United States)

    Crosson, William L; Al-Hamdan, Mohammad Z.; Economou, Sigrid, A.; Estes, Maurice G.; Estes, Sue M.; Puckett, Mark; Quattrochi, Dale A

    2013-01-01

    In the United States, extreme heat is the most deadly weather-related hazard. In the face of a warming climate and urbanization, which contributes to local-scale urban heat islands, it is very likely that extreme heat events (EHEs) will become more common and more severe in the U.S. In a NASA-funded project supporting the National Climate Assessment, we are providing historical and future measures of extreme heat to enable assessments of the impacts of heat on public health over the coterminous U.S. We use atmospheric temperature and humidity information from meteorological reanalysis and from Global Climate Models (GCMs) to provide data on past and future heat events. The project s emphasis is on providing assessments of the magnitude, frequency and geographic distribution of extreme heat in the U.S. to facilitate public health studies. In our approach, long-term climate change is captured with GCM output, and the temporal and spatial characteristics of short-term extremes are represented by the reanalysis data. Two future time horizons, 2040 and 2090, are the focus of future assessments; these are compared to the recent past period of 1981-2000. We are characterizing regional-scale temperature and humidity conditions using GCM output for two climate change scenarios (A2 and A1B) defined in the Special Report on Emissions Scenarios (SRES). For each future period, 20 years of multi-model GCM output have been analyzed to develop a heat stress climatology based on statistics of extreme heat indicators. Differences between the two future and past periods have been used to define temperature and humidity changes on a monthly time scale and regional spatial scale. These changes, combined with hourly historical meteorological data at a spatial scale (12 km) much finer than that of GCMs, enable us to create future climate realizations, from which we compute the daily heat stress measures and related spatially-specific climatological fields. These include the mean annual

  17. Direct shortwave forcing of climate by anthropogenic sulfate aerosol: Sensitivity to particle size, composition, and relative humidity

    Energy Technology Data Exchange (ETDEWEB)

    Nemesure, S.; Wagener, R.; Schwartz, S.E. [Brookhaven National Lab., Upton, New York (United States)

    1996-04-01

    Recent estimates of global or hemispheric average forcing of climate by anthropogenic sulfate aerosol due to scattering of shortwave radiation are uncertain by more than a factor of 2. This paper examines the sensitivity of forcing to these microphysical properties for the purposes of obtaining a better understanding of the properties required to reduce the uncertainty in the forcing.

  18. Climate scenarios for semi-arid and sub-humid regions. A comparison of climate scenarios for the dryland regions, in West Africa from 1990 to 2050

    NARCIS (Netherlands)

    van den Born GJ; Schaeffer M; Leemans R; NOP

    2001-01-01

    The identification of climate scenarios for dryland areas in Sub-Saharan West Africa is part of a project to assess the impact of climate change on water availability, agriculture and food security in drylands (ICCD-project). The project is financed by Netherlands Research Programme on Global Air

  19. A Systematic Review Of Thermal And Moisture Performance Of Straw-Bale Houses In Hot And Humid Climates

    Directory of Open Access Journals (Sweden)

    Ikenna Stephen Ezennia

    2017-01-01

    Full Text Available As architects and home-owners look for innovative ways to help reduce their carbon footprint in the campaign against climate change straw bale could become a new tool in the building industrys armory. In order to bring this form of building into the mainstream sector as well as benefit from its inherent low carbon and high insulation characteristics it is necessary to guarantee the long-term durability of the straw. Sources of data included extensive literature search of relevant English language articles and the results of literature search of Elsevier Science Direct ISI Web of Knowledge ProQuest Central Scopus and Google. This study strives to make an exhaustive review of straw-bale performance in different climates and respective improvements from an energy efficiency perspective. This research revealed that when straw-bale buildings are constructed using the correct and specific technique moisture and thermal intrusion did not seem to be detrimental to the health of the building regardless of the climate. Furthermore building with straw can lead to low thermal transfer relatively high thermal inertia and high moisture regulation capacity. The study concluded that at a time when the importance of building sustainably is widely accepted it would seem imperative that the potential of building systems like this that use renewable resources readily available and have low embodied energy is further studied.

  20. Armoured mud balls as a result of ephemeral fluvial flood in a humid climate: Modern example from Guizhou Province, South China

    Directory of Open Access Journals (Sweden)

    Gerhard H. Bachmann

    2014-10-01

    Full Text Available Armoured mud balls were observed after rainfall and a short flood in the otherwise dry Xiaohe (small river valley of Guanling County, Guizhou Province, South China, approximately 30 km southwest of Guanling City. Armoured mud balls are most common in semiarid climates, but rather unusual in a humid climate as in Guizhou. A number of well-rounded mud balls, 2–20 cm in diameter, were found lying on the gravel of the Xiaohe gully floor. The mud balls consist of sticky, light brown and slightly mottled clay without carbonate content. The surfaces of the mud balls were studded with rims of sand- or gravel-size limestone clasts, collected during bedload transport, as is typical for armoured mud balls. The mud balls originated from alluvial mudstone deposits of the valley floor and cliff that are most likely derived from the weathering and karstification of bedrock limestones. Such mudstones with high clay content seem to be especially well suited for forming armoured mud balls. As flood events are rather common in the area, the formation of armoured mud balls should be very frequent in the Xiaohe valley and similar valleys nearby, giving the possibility for further and more detailed studies. To the best of our knowledge this is the first description of armoured mud balls in China.

  1. Building America Residential System Research Results: Achieving 30% Whole House Energy Savings Level in Mixed-Humid Climates; January 2006 - December 2006

    Energy Technology Data Exchange (ETDEWEB)

    Building America Industrialized Housing Partnership (BAIHP); Building Industry Research Alliance (BIRA); Building Science Consortium (BSC); Consortium for Advanced Residential Buildings (CARB); Davis Energy Group (DEG); IBACOS; National Association of Home Builders Research Center (NAHBRC); National Renewable Energy Laboratory (NREL)

    2006-12-01

    The Building America program conducts the system research required to reduce risks associated with the design and construction of homes that use an average of 30% to 90% less total energy for all residential energy uses than the Building America Research Benchmark, including research on homes that will use zero net energy on annual basis. To measure the program's progress, annual research milestones have been established for five major climate regions in the United States. The system research activities required to reach each milestone take from 3 to 5 years to complete and include research in individual test houses, studies in pre-production prototypes, and research studies with lead builders that provide early examples that the specified energy savings level can be successfully achieved on a production basis. This report summarizes research results for the 30% energy savings level and demonstrates that lead builders can successfully provide 30% homes in the Mixed-Humid Climate Region on a cost-neutral basis.

  2. NUTRITIVE QUALITY OF TEN GRASSES DURING THE RAINY SEASON IN A HOT-HUMID CLIMATE AND ULTISOL SOIL

    Directory of Open Access Journals (Sweden)

    Rodrigo Ortega-Gómez

    2011-11-01

    Full Text Available The nutritive quality of ten grasses harvested at 3, 6, 9 and 12 weeks of regrowth was assessed during the rainy season (August-October 2008, in the humid tropics of Veracruz, Mexico. Grasses tested included four Brachiaria spp.: “insurgente”–B. brizantha, “signal”–B. decumbens, Chetumal–B. humidicola, “mulato I”–B. brizantha x B. ruziziensis; three Panicum maximum: Mombasa, “privilegio”, Tanzania; and three Pennisetum spp.: Taiwán, and the hybrids P. purpureum x P. glaucum “Cuban” king grass and “purple” king grass. Means for crude protein by grass group were: Pennisetum spp. (9.9 % = P. maximum (8.7 % > Brachiaria spp. (7.6 %, whereas means for in situ dry matter disappearance (ISD were: Pennisetum spp. (69.7 % > Brachiaria spp. (65.1 % > P. maximum (59.7 %. Crude protein and ISD significantly decreased by 0.42 % and 1.50 % per week. Neutral detergent fiber was not affected by model effects (mean 71.4 %. Means for acid detergent fiber (ADF by grass group were: P. maximum (47.6 % = Pennisetum spp. (44.0 % > Brachiaria spp. (42.8 %, whereas means for lignin (LIG were: P. maximum (8.5 % > Pennisetum spp. (7.6 % > Brachiaria spp. (6.7 %. The ADF and LIG significantly increased by 1.21 % and 0.19 % per week. Pennisetum spp. had the highest nutritive value at all regrowth ages.

  3. Freshwater fluxes into the subpolar North Atlantic from secular trends in Arctic land ice mass balance

    Science.gov (United States)

    Bamber, J. L.; Enderlin, E. M.; Howat, I. M.; Wouters, B.; van den Broeke, M.

    2015-12-01

    Freshwater fluxes (FWF) from river runoff and precipitation minus evaporation for the pan Arctic seas are relatively well documented and prescribed in ocean GCMs. Fluxes from Greenland and Arctic glaciers and ice caps on the other hand are generally ignored, despite their potential impacts on ocean circulation and marine biology and growing evidence for changes to the hydrography of parts of the subpolar North Atlantic. In a previous study we determined the FWF from Greenland for the period 1958-2010 using a combination of observations and regional climate modeling. Here, we update the analysis with data from new satellite observations to extend the record both in space and time. The new FWF estimates cover the period 1958-2014 and include the Canadian, Russian and Norwegian Arctic (Svalbard) in addition to the contributions from Greenland. We combine satellite altimetry (including CryoSat 2) with grounding line flux data, regional climate modeling of surface mass balance and gravimetry to produce consistent estimates of solid ice and liquid FWF into the Arctic and North Atlantic Oceans. The total cumulative FWF anomaly from land ice mass loss started to increase significantly in the mid 1990s and now exceeds 5000 km^3, a value that is about half of the Great Salinity Anomaly of the 1970s. The majority of the anomaly is entering two key areas of deep water overturning in the Labrador and Irminger Seas, at a rate that has been increasing steadily over the last ~20 years. Since the mid 2000s, however, the Canadian Arctic archipelago has been making a significant contribution to the FW anomaly entering Baffin Bay. Tracer experiments with eddy-permitting ocean GCMs suggest that the FW input from southern Greenland and the Canadian Arctic should accumulate in Baffin Bay with the potential to affect geostrophic circulation, stratification in the region and possibly the strength of the Atlantic Meridional Overturning Circulation. We also examine the trajectory of

  4. Low-frequency and high-frequency changes in temperature and effective humidity during the Holocene in south-central Sweden: implications for atmospheric and oceanic forcings of climate

    Energy Technology Data Exchange (ETDEWEB)

    Seppae, H. [University of Helsinki, Department of Geology, 64, Helsinki (Finland); Hammarlund, D. [Lund University, GeoBiosphere Science Centre, Quaternary Sciences, Lund (Sweden); Antonsson, K. [Uppsala University, Department of Earth Sciences, Uppsala (Sweden)

    2005-08-01

    An integrated use of independent palaeoclimatological proxy techniques that reflect different components of the climate system provides a potential key for functional analysis of past climate changes. Here we report a 10,000 year quantitative record of annual mean temperature (T{sub ann}), based on pollen-climate transfer functions and pollen-stratigraphical data from Lake Flarken, south-central Sweden. The pollen-based temperature reconstruction is compared with a reconstruction of effective humidity, as reflected by a {delta}{sup 18}O record obtained on stratigraphy of lacustrine carbonates from Lake Igelsjoen, c. 10 km from Lake Flarken, which gives evidence of pronounced changes in effective humidity. The relatively low T{sub ann}, and high effective humidity as reflected by a low evaporation/inflow ratio suggest a maritime early Holocene climate (10,000-8,300 cal year BP), seemingly incompatible with the highly seasonal solar insolation configuration. We argue that the maritime climate was due to the stronger-than-present zonal flow, enhanced by the high early Holocene sea-surface temperatures in the North Atlantic. The maritime climate mode was disrupted by the abrupt cold event at 8,200 cal year BP, followed at 8,000 cal year BP by a stable Holocene Thermal Maximum. The latter was characterized by T{sub ann} values about 2.5 C higher than at present and markedly dry conditions, indicative of stable summer-time anti-cyclonic circulation, possibly corresponding with modern blocking anticyclonic conditions. The last 4,300 year period is characterized by an increasingly cold, moist, and unstable climate. The results demonstrate the value of combining two independent palaeoclimatic proxies in enhancing the reliability, generality, and interpretability of the palaeoclimatic results. Further methodological refinements especially in resolving past seasonal climatic contrasts are needed to better understand the role of different forcing factors in driving millennial

  5. To Investigate the Influence of Building Envelope and Natural Ventilation on Thermal Heat Balance in Office Buildings in Warm and Humid Climate

    Science.gov (United States)

    Kini, Pradeep G.; Garg, Naresh Kumar; Kamath, Kiran

    2017-07-01

    India’s commercial building sector is witnessing robust growth. India continues to be a key growth market among global corporates and this is reflective in the steady growth in demand for prime office space. A recent trend that has been noted is the increase in demand for office spaces not just in major cities but also in smaller tier II and Tier III cities. Growth in the commercial building sector projects a rising trend of energy intensive mechanical systems in office buildings in India. The air conditioning market in India is growing at 25% annually. This is due to the ever increasing demand to maintain thermal comfort in tropical regions. Air conditioning is one of the most energy intensive technologies which are used in buildings. As a result India is witnessing significant spike in energy demand and further widening the demand supply gap. Challenge in India is to identify passive measures in building envelope design in office buildings to reduce the cooling loads and conserve energy. This paper investigates the overall heat gain through building envelope components and natural ventilation in warm and humid climate region through experimental and simulation methods towards improved thermal environmental performance.

  6. Experimental performance evaluation of solid concrete and dry insulation materials for passive buildings in hot and humid climatic conditions

    International Nuclear Information System (INIS)

    Rehman, Hassam Ur

    2017-01-01

    average of 22–75% at south wall during summer. Similarly, free floating analysis was done during winter and the measurements showed the behaviour of the heat flux flow and the variations in room temperature due to the variation of thermal mass caused by the difference in heat capacities of the façade with and without insulation. Heat flux and temperature variations were minimal in cases of insulated buildings when compared against a reference building in the winter free flow tests. The temperature variation is limited to 2 °C in case of insulated buildings compared to 6 °C in the reference case caused by high thermal inertia. Thus, insulation is essential in summer as well as in winter for the buildings in Middle East and North Africa (MENA). Overall, this paper provides a novel view on the most significant contributors to the thermal behaviour of the structure, and presents a methodology on the outdoor tests with various materials, that can significantly improve the thermal behaviour of the buildings in the extremely hot climate.

  7. Lagrangian study of transport of subarctic water across the Subpolar Front in the Japan Sea

    Science.gov (United States)

    Prants, Sergey V.; Uleysky, Michael Yu.; Budyansky, Maxim V.

    2018-05-01

    The southward near-surface transport of transformed subarctic water across the Subpolar Front in the Japan Sea is simulated and analyzed based on altimeter data from January 1, 1993 to December 31, 2017. Computing Lagrangian indicators for a large number of synthetic particles, advected by the AVISO velocity field, we find preferred transport pathways across the Subpolar Front. The southward transport occurs mainly in the central part of the frontal zone due to suitable dispositions of mesoscale eddies promoting propagation of subarctic water to the south. It is documented with the help of Lagrangian origin and L-maps and verified by the tracks of available drifters. The transport of transformed subarctic water to the south is compared with the transport of transformed subtropical water to the north simulated by Prants et al. (Nonlinear Process Geophys 24(1):89-99, 2017c).

  8. Sensitivity of North Atlantic subpolar gyre and overturning to stratification-dependent mixing: response to global warming

    Energy Technology Data Exchange (ETDEWEB)

    Marzeion, Ben [Massachusetts Institute of Technology, EAPS, Cambridge, MA (United States); Nansen Environmental and Remote Sensing Center and Bjerknes Centre for Climate Research, Bergen (Norway); University of Innsbruck, Tropical Glaciology Group, Institute of Geography, Innsbruck (Austria); Levermann, Anders [Potsdam University, Earth System Analysis, Potsdam Institute for Climate Impact Research and Institute of Physics, Potsdam (Germany); Mignot, Juliette [Universite Pierre et Marie Curie, LOCEAN, Paris (France)

    2010-04-15

    We use a reduced complexity climate model with a three-dimensional ocean component and realistic topography to investigate the effect of stratification-dependent mixing on the sensitivity of the North Atlantic subpolar gyre (SPG), and the Atlantic meridional overturning circulation (AMOC), to idealized CO{sub 2} increase and peaking scenarios. The vertical diffusivity of the ocean interior is parameterized as {kappa} {proportional_to} N {sup -{alpha}}, where N is the local buoyancy frequency. For all parameter values 0 {<=} {alpha} {<=} 3, we find the SPG, and subsequently the AMOC, to weaken in response to increasing CO{sub 2} concentrations. The weakening is significantly stronger for {alpha} {>=} {alpha}{sub cr} {approx} 1.5. Depending on the value of {alpha}, two separate model states develop. These states remain different after the CO{sub 2} concentration is stabilized, and in some cases even after the CO{sub 2} concentration has been decreased again to the pre-industrial level. This behaviour is explained by a positive feedback between stratification and mixing anomalies in the Nordic Seas, causing a persistent weakening of the SPG. (orig.)

  9. Unveiling current Guanaco distribution in chile based upon niche structure of phylogeographic lineages: Andean puna to subpolar forests.

    Science.gov (United States)

    González, Benito A; Samaniego, Horacio; Marín, Juan Carlos; Estades, Cristián F

    2013-01-01

    Niche description and differentiation at broad geographic scales have been recent major topics in ecology and evolution. Describing the environmental niche structure of sister taxa with known evolutionary trajectories stands out as a useful exercise in understanding niche requirements. Here we model the environmental niche structure and distribution of the recently resolved phylogeography of guanaco (Lama guanicoe) lineages on the western slope of the southern Andes. Using a maximum entropy framework, field data, and information on climate, topography, human density, and vegetation cover, we identify differences between the two subspecies (L.g.cacsilensis, L.g.guanicoe) and their intermediate-hybrid lineage, that most likely determine the distribution of this species. While aridity seems to be a major factor influencing the distribution at the species-level (annual precipitation ecological and/or evolutionary processes are shaping the niche of guanacos in Chile, producing discrepancies when comparing range distribution at the species-level (81,756 km(2)) with lineages-level (65,321 km(2)). The subspecies-specific description of niche structure is provided here based upon detailed spatial distribution of the lineages of guanacos in Chile. Such description provides a scientific tool to further develop large scale plans for habitat conservation and preservation of intraspecific genetic variability for this far ranging South American camelid, which inhabits a diversity of ecoregion types from Andean puna to subpolar forests.

  10. An assessment of efficient water heating options for an all-electric single family residence in a mixed-humid climate.

    Science.gov (United States)

    Balke, Elizabeth C; Healy, William M; Ullah, Tania

    2016-12-01

    An evaluation of a variety of efficient water heating strategies for an all-electric single family home located in a mixed-humid climate is conducted using numerical modeling. The strategies considered include various combinations of solar thermal, heat pump, and electric resistance water heaters. The numerical model used in the study is first validated against a year of field data obtained on a dual-tank system with a solar thermal preheat tank feeding a heat pump water heater that serves as a backup. Modeling results show that this configuration is the most efficient of the systems studied over the course of a year, with a system coefficient of performance (COP sys ) of 2.87. The heat pump water heater alone results in a COP sys of 1.9, while the baseline resistance water heater has a COP sys of 0.95. Impacts on space conditioning are also investigated by considering the extra energy consumption required of the air source heat pump to remove or add heat from the conditioned space by the water heating system. A modified COP sys that incorporates the heat pump energy consumption shows a significant drop in efficiency for the dual tank configuration since the heat pump water heater draws the most heat from the space in the heating season while the high temperatures in the solar storage tank during the cooling season result in an added heat load to the space. Despite this degradation in the COP sys , the combination of the solar thermal preheat tank and the heat pump water heater is the most efficient option even when considering the impacts on space conditioning.

  11. An assessment of efficient water heating options for an all-electric single family residence in a mixed-humid climate

    Science.gov (United States)

    Balke, Elizabeth C.; Healy, William M.; Ullah, Tania

    2016-01-01

    An evaluation of a variety of efficient water heating strategies for an all-electric single family home located in a mixed-humid climate is conducted using numerical modeling. The strategies considered include various combinations of solar thermal, heat pump, and electric resistance water heaters. The numerical model used in the study is first validated against a year of field data obtained on a dual-tank system with a solar thermal preheat tank feeding a heat pump water heater that serves as a backup. Modeling results show that this configuration is the most efficient of the systems studied over the course of a year, with a system coefficient of performance (COPsys) of 2.87. The heat pump water heater alone results in a COPsys of 1.9, while the baseline resistance water heater has a COPsys of 0.95. Impacts on space conditioning are also investigated by considering the extra energy consumption required of the air source heat pump to remove or add heat from the conditioned space by the water heating system. A modified COPsys that incorporates the heat pump energy consumption shows a significant drop in efficiency for the dual tank configuration since the heat pump water heater draws the most heat from the space in the heating season while the high temperatures in the solar storage tank during the cooling season result in an added heat load to the space. Despite this degradation in the COPsys, the combination of the solar thermal preheat tank and the heat pump water heater is the most efficient option even when considering the impacts on space conditioning. PMID:27990058

  12. Reproductive and productive performances of Santa Inês ewes submitted to breeding in different periods of the Amazonian humid tropical climate.

    Science.gov (United States)

    Soares, Felipe Nogueira; Oliveira, Maria Emilia Franco; Padilha-Nakaghi, Luciana Cristina; de Oliveira, Luís Guilherme; Feliciano, Marcus Antônio Rossi; de Oliveira, Felipe Brener Bezerra; Teixeira, Pedro Paulo Maia; Vicente, Wilter Ricardo Russiano; Faturi, Cristian; Rodrigues, Luiz Fernando de Souza

    2015-12-01

    The objective of this study was to evaluate the reproductive and productive performance of Santa Inês ewes bred at different times of the year in humid tropical climate. One hundred and forty-eight Santa Inês ewes were grouped according to the time of the year of their breeding season (i.e., mating period) (dry/wet, wet, wet/dry, and dry season). The service type was natural mating and the ewes and rams were kept together every night for 45 days. Reproductive efficiency was assessed by service, pregnancy, lambing, prolificacy, twinning, pregnancy loss, weaning, and lamb mortality rates. Ewes were weighed at the beginning and at the end of the breeding season and before and after parturition, and sequential weighing of the lambs was performed (at birth, 15, 30, 60, and 90 days). Reproductive efficiency index (number of lambs weaned/total of served ewes) and productive efficiency (kg of weaned lamb/kg of served or lambed ewes) were calculated. All ewes expressed estrus early in the breeding season; however, a higher percentage (53.5 and 7.1 % at 30 and 45 days, respectively) of ewes returned to estrus during the wet/dry period. The lower rates (13.9 %) of return to estrus at 30 days were during the wet season (P  0.05) effects of breeding seasons on the remaining reproductive rates. Ewes that lambed during the wet/dry transition period weighted less, before (40.5 ± 2.5 kg) and after (38.6 ± 1.6 kg) parturition, than those of other groups (P ewes, respectively; P ewes served in the dry season. The reproductive performance of Santa Inês ewes was not significantly influenced by the period of the year in which the breeding seasons took place, allowing for four breeding seasons a year in the Amazon region. Variations between periods in return to estrus rates, weight of ewes close to parturition and lamb weight at weaning indicate that climate changes can also affect reproductive rates.

  13. The effects of window alternatives on energy efficiency and building economy in high-rise residential buildings in moderate to humid climates

    International Nuclear Information System (INIS)

    Yaşar, Yalçın; Kalfa, Sibel Maçka

    2012-01-01

    Highlights: ► We investigated energy and economy efficiency of window alternatives in Trabzon. ► Energy consumptions of eight window alternatives were simulated and discussed. ► Window alternatives’s life cycle costs were calculated and compared. ► We suggested appropriate energy and economy efficient window alternatives. ► The study defines useful guidelines to select appropriate window alternatives. - Abstract: Currently, focused efforts are being made to determine the influence of windows on the energy consumption and economy of high-rise buildings. Certain window designs and appropriate glazing systems reduce building energy consumption for heating and cooling and contribute to building economy. This paper addresses double-glazed window units that are composed of tinted glass; clear reflective glass; low emissivity (low-e) glass; and smart glass (one surface consists of a high-performance, heat-reflective glass, and other surface has a low-emissivity coated). These materials reduce the heating and cooling loads of buildings by providing solar control and heat conservation. The aim of this study was to investigate the effects of these alternative units, rather than readily available double-glazed units, in two types of flats. The flats have the same construction and operating system, but they have different plan types with regard to building energy consumption and building economy as it relates to life cycle cost analysis. For this study, we selected buildings in Trabzon, in Climate Region II of Turkey, due to its moderate-humid climate. F- and C-type high-rise residential blocks, with flats composed of two to three bedrooms, constructed by the Republic of Turkey’s Prime Ministry Housing Development Administration of Turkey (TOKİ) are used as models for the simulation. The flat plans in these blocks are modeled using DesignBuilder v.1.8 energy simulation software. The simulation results show that smart-glazed units and those with low emissivity

  14. Overview of humidity driven reliability issues of electronics

    DEFF Research Database (Denmark)

    Ambat, Rajan

    2017-01-01

    Electronic control units, power modules, and consumer electronics are used today in a wide variety of varying climatic conditions. Varying external climatic conditions of temperature and humidity can cause an uncontrolled local climate inside the device enclosure. Uncontrolled humidity together w...

  15. Humidity level In psychrometric processes

    International Nuclear Information System (INIS)

    Mojsovski, Filip

    2008-01-01

    When a thermal engineer needs to control, rather than merely moderate humidity, he must focus on the moisture level as a separate variable - not simply an addition of temperature control. Controlling humidity generally demands a correct psychrometric approach dedicated to that purpose [1].Analysis of the humidity level in psychrometric thermal processes leads to relevant data for theory and practice [2]. This paper presents: (1) the summer climatic curve for the Skopje region, (2) selected results of investigation on farm dryers made outside laboratories. The first purpose of such activity was to examine relations between weather conditions and drying conditions. The estimation of weather condition for the warmest season of the year was realized by a summer climatic curve. In the science of drying, basic drying conditions are temperature, relative humidity and velocity of air, thickness of dried product and dryer construction. The second purpose was to realize correct prediction of drying rates for various psychrometrics drying processes and local products. Test runs with the dryer were carried out over a period of 24 h, using fruits and vegetables as experimental material. Air flow rate through the dryer of 150 m3/h, overall drying rate of 0.04 kg/h and air temperature of 65 oC were reached. Three types of solar dryers, were exploited in the research.

  16. The Sub-Polar Gyre Index - a community data set for application in fisheries and environment research

    DEFF Research Database (Denmark)

    Berx, Barbara; Payne, Mark

    2017-01-01

    Scientific interest in the sub-polar gyre of the North Atlantic Ocean has increased in recent years. The sub-polar gyre has contracted and weakened, and changes in circulation pathways have been linked to changes in marine ecosystem productivity. To aid fisheries and environmental scientists, we...... series length are explored but found not to be important factors in terms of the SPG-I's interpretation. Our time series compares well with indices presented previously. The SPG-I time series is freely available online (http://dx.doi.org/10.7489/1806-1), and we invite the community to access, apply...

  17. Humid Heat Waves at different warming levels

    Science.gov (United States)

    Russo, S.; Sillmann, J.; Sterl, A.

    2017-12-01

    The co-occurrence of consecutive hot and humid days during a heat wave can strongly affect human health. Here, we quantify humid heat wave hazard in the recent past and at different levels of global warming.We find that the magnitude and apparent temperature peak of heat waves, such as the ones observed in Chicago in 1995 and China in 2003, have been strongly amplified by humidity. Climate model projections suggest that the percentage of area where heat wave magnitude and peak are amplified by humidity increases with increasing warming levels. Considering the effect of humidity at 1.5o and 2o global warming, highly populated regions, such as the Eastern US and China, could experience heat waves with magnitude greater than the one in Russia in 2010 (the most severe of the present era).The apparent temperature peak during such humid-heat waves can be greater than 55o. According to the US Weather Service, at this temperature humans are very likely to suffer from heat strokes. Humid-heat waves with these conditions were never exceeded in the present climate, but are expected to occur every other year at 4o global warming. This calls for respective adaptation measures in some key regions of the world along with international climate change mitigation efforts.

  18. Evolution of subpolar North Atlantic surface circulation since the early Holocene inferred from planktic foraminifera faunal and stable isotope records

    DEFF Research Database (Denmark)

    Staines-Urias, Francisca; Kuijpers, Antoon; Korte, Christoph

    2013-01-01

    of the Faroe Islands, are located in the transitional area where surface waters of subpolar and subtropical origin mix before entering the Arctic Mediterranean. In these areas, large-amplitude millennial variability in the characteristics of the upper-water column appears modulated by changes in the intensity...

  19. How the Subpolar gyre strength influences phytoplankton blooms dynamics in the North Atlantic

    DEFF Research Database (Denmark)

    Ferreira, Ana Sofia; Payne, Mark; MacKenzie, Brian

    2012-01-01

    height (SSH, from the AVISO project) as a proxy of current strength. Three regions were strategically chosen to characterize positions relative to the NASPG, describing: region 1—the northern part of NASPG, including the Irminger Current (IC); region 2—the North Atlantic Current (NAC), its northwards......Changes in the North Atlantic Subpolar gyre (NASPG) have been linked to the interannual variability of primary production. However, little is known about the mechanisms behind both environmental processes, and how the NASPG strength may extend its potential impacts to higher trophic levels......, including early life stages of commercial fish species. We assess NASPG strength effect on North Atlantic phytoplankton bloom dynamics. We analyse time‐series (from 1998 to 2010) of chlorophyll a (Chl a, from the Globcolour project) annual anomaly as a proxy of phytoplankton abundance, and of sea surface...

  20. Lower Carboniferous Siderites: A Product of Bottom Seeps and Bacterial Metanogenesis (Subpolar Urals)

    Science.gov (United States)

    Antoshkina, A. I.; Ryabinkina, N. N.

    2018-02-01

    Complex modern micro- and spectroscopic methods for study of siderite concretions in the Lower Carboniferous terrigenous strata on the Kozhym River (Subpolar Urals) have shown that its formation was caused by destruction of clay minerals due to the activity of bacterial communities. The abundance of these bacteria was caused by gas-fluid seeps and bacterial methanogenesis processes in bottom deposits. In basins with normal marine fauna, this led to local desalination, hydrogen sulfide contamination, mass collapse of primary organisms, and the development of element-specific bacteria. The occurrence of these bacteria caused the formation of specific authigenic mineralization in the concretion of sideritic bacteriolites: the framboidal pyrite, sphalerite, galenite, barite, sulfoselenides, and tellurides.

  1. On the mechanisms behind decadal heat content changes in the eastern subpolar gyre

    Science.gov (United States)

    Desbruyères, Damien; Mercier, Herlé; Thierry, Virginie

    2015-03-01

    Historical and modern hydrographic data show substantial decadal variability in the heat content (HC) of the eastern subpolar North Atlantic. Those changes are here investigated in an eddy-permitting simulation (ORCA025-G70) forced by reanalysis products for the period 1965-2004. The observed and simulated decadal signal is characterized by a strong cooling in the 1960s and 1970s, a period of minor changes in the 1980s, and a strong warming in the 1990s and 2000s. A heat budget calculation is performed within a box bounded by the Greenland-Scotland sills and the Cape Farewell (Greenland)-Portugal A25-Ovide section. The decadal variability of HC is mainly governed by the integrated effect of anomalous oceanic heat transport across A25-Ovide (HTA25), with local air-sea heat fluxes playing a damping role. The impact of temperature changes acting upon the mean oceanic circulation is shown to dominate the long-term behavior of HTA25 . Through Lagrangian experiments, we show that temperature anomalies advected by the mean circulation across A25-Ovide are mostly created by the gyre circulation anomalies upstream of A25-Ovide and the associated changes in the relative proportion of cold subpolar and warm subtropical waters feeding the northern and southern branches of the North Atlantic Current. These temperature anomalies induce large-scale changes in the pycnocline slope east of Reykjanes Ridge along A25-Ovide: when the NAC is relatively cold (warm), the main pycnocline moves upward (downward) in the Iceland Basin and on top of Reykjanes Ridge, thereby increasing (decreasing) the pycnocline slope. The resulting velocity anomalies lead to heat transport changes that strongly oppose the thermally-driven heat transport anomalies.

  2. Time dependency of the prediction skill for the North Atlantic subpolar gyre in initialized decadal hindcasts

    Science.gov (United States)

    Brune, Sebastian; Düsterhus, André; Pohlmann, Holger; Müller, Wolfgang A.; Baehr, Johanna

    2017-11-01

    We analyze the time dependency of decadal hindcast skill in the North Atlantic subpolar gyre within the time period 1961-2013. We compare anomaly correlation coefficients and temporal interquartile ranges of total upper ocean heat content and sea surface temperature for three differently initialized sets of hindcast simulations with the global coupled model MPI-ESM. All initializations use weakly coupled assimilation with the same full value nudging in the atmospheric component and different assimilation techniques for oceanic temperature and salinity: (1) ensemble Kalman filter assimilating EN4 observations and HadISST data, (2) nudging of anomalies to ORAS4 reanalysis, (3) nudging of full values to ORAS4 reanalysis. We find that hindcast skill depends strongly on the evaluation time period, with higher hindcast skill during strong multiyear trends, especially during the warming in the 1990s and lower hindcast skill in the absence of such trends. Differences between the prediction systems are more pronounced when investigating any 20-year subperiod within the entire hindcast period. In the ensemble Kalman filter initialized hindcasts, we find significant correlation skill for up to 5-8 lead years, albeit along with an overestimation of the temporal interquartile range. In the hindcasts initialized by anomaly nudging, significant correlation skill for lead years greater than two is only found in the 1980s and 1990s. In the hindcasts initialized by full value nudging, correlation skill is consistently lower than in the hindcasts initialized by anomaly nudging in the first lead years with re-emerging skill thereafter. The Atlantic meridional overturning circulation reacts on the density changes introduced by oceanic nudging, this limits the predictability in the subpolar gyre in the first lead years. Overall, we find that a model-consistent assimilation technique can improve hindcast skill. Further, the evaluation of 20 year subperiods within the full hindcast period

  3. Terrain Analysis Procedural Guide for Climate,

    Science.gov (United States)

    1980-09-01

    days a year at many locations. D. HUMID MICROTHERMAL CLIMATES. The humid microthermal climate occurs in the Northern Hemisphere northward from the...subarctic are the principal types of microthermal climate. 71 1. Humid Continental Climates. These climates border the marine west coast climatic regions...frequently occur during summer in prairie regions. Regions on the southern margin of microthermal climates have long, hot and humid summers lasting from

  4. The effect of combining a relative-humidity-sensitive ventilation system with the moisture-buffering capacity of materials on indoor climate and energy efficiency of buildings

    Energy Technology Data Exchange (ETDEWEB)

    Woloszyn, Monika [Universite de Lyon, Lyon F-69003 (France); Universite Lyon1, Villeurbanne F-69622 (France); INSA-Lyon, CETHIL UMR CNRS 5008, bat. Sadi Carnot, F-69621 Villeurbanne cedex (France); Kalamees, Targo [Chair of Building Physics and Architecture, Tallinn University of Technology, Ehiteja tee 5 19086 (Estonia); Olivier Abadie, Marc [Pontifical Catholic University of Parana - PUCPR/CCET-Thermal Systems Laboratory, Rua Imaculada Conceicao, 1155 Curitiba, PR 80215-901 (Brazil); LEPTIAB-University of La Rochelle, Avenue M. Crepeau, 17000 La Rochelle (France); Steeman, Marijke [Department of Architecture and Urban Planning, UGENT-Ghent University, J. Plateaustraat 22, 9000 Ghent (Belgium); Sasic Kalagasidis, Angela [Department of Building Technology, Chalmers University of Technology, Sven Hultins gata 8, 412 96 Gothenburg (Sweden)

    2009-03-15

    Indoor moisture management, which means keeping the indoor relative humidity (RH) at correct levels, is very important for whole building performance in terms of indoor air quality (IAQ), energy performance and durability of the building. In this study, the effect of combining a relative-humidity-sensitive (RHS) ventilation system with indoor moisture buffering materials was investigated. Four comprehensive heat-air-moisture (HAM) simulation tools were used to analyse the performance of different moisture management strategies in terms of IAQ and of energy efficiency. Despite some differences in results, a good agreement was found and similar trends were detected from the results, using the four different simulation tools. The results from simulations demonstrate that RHS ventilation reduces the spread between the minimum and maximum values of the RH in the indoor air and generates energy savings. Energy savings are achieved while keeping the RH at target level, not allowing for possible risk of condensations. The disadvantage of this type of demand controlled-ventilation is that other pollutants (such as CO{sub 2}) may exceed target values. This study also confirmed that the use of moisture-buffering materials is a very efficient way to reduce the amplitude of daily moisture variations. It was possible, by the combined effect of ventilation and wood as buffering material, to keep the indoor RH at a very stable level. (author)

  5. The Design of Temperature and Humidity Chamber Monitor and Controller

    OpenAIRE

    Tibebu, Simachew

    2016-01-01

    The temperature and humidity chamber, (climate chamber) is a device located at the Technobothnia Education and Research Center that simulates different climate conditions. The simulated environment is used to test the capabilities of electrical equipment in different temperature and humidity conditions. The climate chamber, among other things houses a dedicated computer, the control PC, and a control software running in it which together are responsible for running and control-ling these simu...

  6. Unveiling current Guanaco distribution in chile based upon niche structure of phylogeographic lineages: Andean puna to subpolar forests.

    Directory of Open Access Journals (Sweden)

    Benito A González

    Full Text Available Niche description and differentiation at broad geographic scales have been recent major topics in ecology and evolution. Describing the environmental niche structure of sister taxa with known evolutionary trajectories stands out as a useful exercise in understanding niche requirements. Here we model the environmental niche structure and distribution of the recently resolved phylogeography of guanaco (Lama guanicoe lineages on the western slope of the southern Andes. Using a maximum entropy framework, field data, and information on climate, topography, human density, and vegetation cover, we identify differences between the two subspecies (L.g.cacsilensis, L.g.guanicoe and their intermediate-hybrid lineage, that most likely determine the distribution of this species. While aridity seems to be a major factor influencing the distribution at the species-level (annual precipitation <900 mm, we also document important differences in niche specificity for each subspecies, where distribution of Northern lineage is explained mainly by elevation (mean = 3,413 m and precipitation seasonality (mean = 161 mm, hybrid lineage by annual precipitation (mean = 139 mm, and Southern subspecies by annual precipitation (mean = 553 mm, precipitation seasonality (mean = 21 mm and grass cover (mean = 8.2%. Among lineages, we detected low levels of niche overlap: I (Similarity Index = 0.06 and D (Schoener's Similarity Index = 0.01; and higher levels when comparing Northern and Southern subspecies with hybrids lineage ( I = 0.32-0.10 and D = 0.12-0.03, respectively. This suggests that important ecological and/or evolutionary processes are shaping the niche of guanacos in Chile, producing discrepancies when comparing range distribution at the species-level (81,756 km(2 with lineages-level (65,321 km(2. The subspecies-specific description of niche structure is provided here based upon detailed spatial distribution of the lineages of guanacos in Chile. Such description

  7. Attribution of observed surface humidity changes to human influence.

    Science.gov (United States)

    Willett, Katharine M; Gillett, Nathan P; Jones, Philip D; Thorne, Peter W

    2007-10-11

    Water vapour is the most important contributor to the natural greenhouse effect, and the amount of water vapour in the atmosphere is expected to increase under conditions of greenhouse-gas-induced warming, leading to a significant feedback on anthropogenic climate change. Theoretical and modelling studies predict that relative humidity will remain approximately constant at the global scale as the climate warms, leading to an increase in specific humidity. Although significant increases in surface specific humidity have been identified in several regions, and on the global scale in non-homogenized data, it has not been shown whether these changes are due to natural or human influences on climate. Here we use a new quality-controlled and homogenized gridded observational data set of surface humidity, with output from a coupled climate model, to identify and explore the causes of changes in surface specific humidity over the late twentieth century. We identify a significant global-scale increase in surface specific humidity that is attributable mainly to human influence. Specific humidity is found to have increased in response to rising temperatures, with relative humidity remaining approximately constant. These changes may have important implications, because atmospheric humidity is a key variable in determining the geographical distribution and maximum intensity of precipitation, the potential maximum intensity of tropical cyclones, and human heat stress, and has important effects on the biosphere and surface hydrology.

  8. North Atlantic variability and its links to European climate over the last 3000 years.

    Science.gov (United States)

    Moffa-Sánchez, Paola; Hall, Ian R

    2017-11-23

    The subpolar North Atlantic is a key location for the Earth's climate system. In the Labrador Sea, intense winter air-sea heat exchange drives the formation of deep waters and the surface circulation of warm waters around the subpolar gyre. This process therefore has the ability to modulate the oceanic northward heat transport. Recent studies reveal decadal variability in the formation of Labrador Sea Water. Yet, crucially, its longer-term history and links with European climate remain limited. Here we present new decadally resolved marine proxy reconstructions, which suggest weakened Labrador Sea Water formation and gyre strength with similar timing to the centennial cold periods recorded in terrestrial climate archives and historical records over the last 3000 years. These new data support that subpolar North Atlantic circulation changes, likely forced by increased southward flow of Arctic waters, contributed to modulating the climate of Europe with important societal impacts as revealed in European history.

  9. Humidity Sensing in Drosophila.

    Science.gov (United States)

    Enjin, Anders; Zaharieva, Emanuela E; Frank, Dominic D; Mansourian, Suzan; Suh, Greg S B; Gallio, Marco; Stensmyr, Marcus C

    2016-05-23

    Environmental humidity influences the fitness and geographic distribution of all animals [1]. Insects in particular use humidity cues to navigate the environment, and previous work suggests the existence of specific sensory mechanisms to detect favorable humidity ranges [2-5]. Yet, the molecular and cellular basis of humidity sensing (hygrosensation) remains poorly understood. Here we describe genes and neurons necessary for hygrosensation in the vinegar fly Drosophila melanogaster. We find that members of the Drosophila genus display species-specific humidity preferences related to conditions in their native habitats. Using a simple behavioral assay, we find that the ionotropic receptors IR40a, IR93a, and IR25a are all required for humidity preference in D. melanogaster. Yet, whereas IR40a is selectively required for hygrosensory responses, IR93a and IR25a mediate both humidity and temperature preference. Consistent with this, the expression of IR93a and IR25a includes thermosensory neurons of the arista. In contrast, IR40a is excluded from the arista but is expressed (and required) in specialized neurons innervating pore-less sensilla of the sacculus, a unique invagination of the third antennal segment. Indeed, calcium imaging showed that IR40a neurons directly respond to changes in humidity, and IR40a knockdown or IR93a mutation reduced their responses to stimuli. Taken together, our results suggest that the preference for a specific humidity range depends on specialized sacculus neurons, and that the processing of environmental humidity can happen largely in parallel to that of temperature. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. The subpolar North Atlantic - Response to North Atlantic oscillation like forcing and Influence on the Atlantic meridional overturning circulation

    Science.gov (United States)

    Lohmann, Katja; Drange, Helge; Jungclaus, Johann

    2010-05-01

    The extent and strength of the North Atlantic subpolar gyre (SPG) changed rapidly in the mid-1990s, going from large and strong in 1995 to substantially weakened in the following years. The abrupt change in the intensity of the SPG is commonly linked to the reversal of the North Atlantic Oscillation (NAO) index, changing from strong positive to negative values, in the winter 1995/96. In this study we investigate the impact of the initial SPG state on its subsequent behavior by means of an ocean general circulation model driven by NCEP-NCAR reanalysis fields. Our sensitivity integrations suggest that the weakening of the SPG cannot be explained by the change in the atmospheric forcing alone. Rather, for the time period around 1995, the SPG was about to weaken, irrespective of the actual atmospheric forcing, due to the ocean state governed by the persistently strong positive NAO during the preceding seven years (1989 to 1995). Our analysis indicates that it was this preconditioning of the ocean, in combination with the sudden drop in the NAO in 1995/96, that lead to the strong and rapid weakening of the SPG in the second half of the 1990s. In the second part, the sensitivity of the low-frequency variability of the Atlantic meridional overturning circulation to changes in the subpolar North Atlantic is investigated using a 2000 year long control integration as well as sensitivity experiments with the MPI-M Earth System Model. Two 1000 year long sensitivity experiments will be performed, in which the low-frequency variability in the overflow transports from the Nordic Seas and in the subpolar deep water formation rates is suppressed respectively. This is achieved by nudging temperature and salinity in the GIN Sea or in the subpolar North Atlantic (up to about 1500m depth) towards a monthly climatology obtained from the last 1000 years of the control integration.

  11. Dissolution of calcium carbonate: observations and model results in the subpolar North Atlantic

    Directory of Open Access Journals (Sweden)

    K. Friis

    2007-01-01

    Full Text Available We investigate the significance of in situ dissolution of calcium carbonate above its saturation horizons using observations from the open subpolar North Atlantic [sNA] and to a lesser extent a 3-D biogeochemical model. The sNA is particularly well suited for observation-based detections of in situ, i.e. shallow-depth CaCO3 dissolution [SDCCD] as it is a region of high CaCO3 production, deep CaCO3 saturation horizons, and precisely-defined pre-formed alkalinity. Based on the analysis of a comprehensive alkalinity data set we find that SDCCD does not appear to be a significant process in the open sNA. The results from the model support the observational findings by indicating that there is not a significant need of SDCCD to explain observed patterns of alkalinity in the North Atlantic. Instead our investigation points to the importance of mixing processes for the redistribution of alkalinity from dissolution of CaCO3 from below its saturation horizons. However, mixing has recently been neglected for a number of studies that called for SDCCD in the sNA and on global scale.

  12. Effects of Thermal Mass, Window Size, and Night-Time Ventilation on Peak Indoor Air Temperature in the Warm-Humid Climate of Ghana

    Directory of Open Access Journals (Sweden)

    S. Amos-Abanyie

    2013-01-01

    Full Text Available Most office buildings in the warm-humid sub-Saharan countries experience high cooling load because of the predominant use of sandcrete blocks which are of low thermal mass in construction and extensive use of glazing. Relatively, low night-time temperatures are not harnessed in cooling buildings because office openings remain closed after work hours. An optimization was performed through a sensitivity analysis-based simulation, using the Energy Plus (E+ simulation software to assess the effects of thermal mass, window size, and night ventilation on peak indoor air temperature (PIAT. An experimental system was designed based on the features of the most promising simulation model, constructed and monitored, and the experimental data used to validate the simulation model. The results show that an optimization of thermal mass and window size coupled with activation of night-time ventilation provides a synergistic effect to obtain reduced peak indoor air temperature. An expression that predicts, indoor maximum temperature has been derived for models of various thermal masses.

  13. Impact of heat stress on conception rate of dairy cows in the moderate climate considering different temperature-humidity index thresholds, periods relative to breeding, and heat load indices.

    Science.gov (United States)

    Schüller, L K; Burfeind, O; Heuwieser, W

    2014-05-01

    The objectives of this retrospective study were to investigate the relationship between temperature-humidity index (THI) and conception rate (CR) of lactating dairy cows, to estimate a threshold for this relationship, and to identify periods of exposure to heat stress relative to breeding in an area of moderate climate. In addition, we compared three different heat load indices related to CR: mean THI, maximum THI, and number of hours above the mean THI threshold. The THI threshold for the influence of heat stress on CR was 73. It was statistically chosen based on the observed relationship between the mean THI at the day of breeding and the resulting CR. Negative effects of heat stress, however, were already apparent at lower levels of THI, and 1 hour of mean THI of 73 or more decreased the CR significantly. The CR of lactating dairy cows was negatively affected by heat stress both before and after the day of breeding. The greatest negative impact of heat stress on CR was observed 21 to 1 day before breeding. When the mean THI was 73 or more in this period, CR decreased from 31% to 12%. Compared with the average maximum THI and the total number of hours above a threshold of more than or 9 hours, the mean THI was the most sensitive heat load index relating to CR. These results indicate that the CR of dairy cows raised in the moderate climates is highly affected by heat stress. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Modulation of Late Cretaceous and Cenozoic climate by variable drawdown of atmospheric pCO2 from weathering of basaltic provinces on continents drifting through the equatorial humid belt

    Directory of Open Access Journals (Sweden)

    D. V. Kent

    2013-03-01

    Full Text Available The small reservoir of carbon dioxide in the atmosphere (pCO2 that modulates climate through the greenhouse effect reflects a delicate balance between large fluxes of sources and sinks. The major long-term source of CO2 is global outgassing from sea-floor spreading, subduction, hotspot activity, and metamorphism; the ultimate sink is through weathering of continental silicates and deposition of carbonates. Most carbon cycle models are driven by changes in the source flux scaled to variable rates of ocean floor production, but ocean floor production may not be distinguishable from being steady since 180 Ma. We evaluate potential changes in sources and sinks of CO2 for the past 120 Ma in a paleogeographic context. Our new calculations show that decarbonation of pelagic sediments by Tethyan subduction contributed only modestly to generally high pCO2 levels from the Late Cretaceous until the early Eocene, and thus shutdown of this CO2 source with the collision of India and Asia at the early Eocene climate optimum at around 50 Ma was inadequate to account for the large and prolonged decrease in pCO2 that eventually allowed the growth of significant Antarctic ice sheets by around 34 Ma. Instead, variation in area of continental basalt terranes in the equatorial humid belt (5° S–5° N seems to be a dominant factor controlling how much CO2 is retained in the atmosphere via the silicate weathering feedback. The arrival of the highly weatherable Deccan Traps in the equatorial humid belt at around 50 Ma was decisive in initiating the long-term slide to lower atmospheric pCO2, which was pushed further down by the emplacement of the 30 Ma Ethiopian Traps near the equator and the southerly tectonic extrusion of SE Asia, an arc terrane that presently is estimated to account for 1/4 of CO2 consumption from all basaltic provinces that account for ~1/3 of the total CO2 consumption by continental silicate weathering (Dessert et al., 2003. A negative climate

  15. Response of apple (malus domestica borkh.) cultivars grafted on two rootstocks under sub-humid temperate climate of azad jammu and kashmir

    International Nuclear Information System (INIS)

    Ahmed, M.J.; Gillani, G.M.; Kiani, F.A.

    2013-01-01

    Nine apple (Malus domestica Borkh.) cultivars grafted on two rootstocks were assessed on morphological and biochemical basis under sub-humid temperate region of Azad Jammu and Kashmir. Starking Delicious, Kala Kulu, Fuji, Red Chief, Royal Gala, Red Labnani, Red Delicious, Star Crimson and Sky Spur grafted on local Crab apple and MM.111 were studied for various growth characteristics. Red Chief exhibited maximum (415.8 cm) plant height on crab apple whereas, more flower (1866) tree-1, higher number (967.0) of fruit set tree/sup -1/, fruits matured (490.0) tree/sup -1/ and maximum (46.33 kg) weight of fruits tree/sup -1/ were recorded on MM.111. Minimum duration (5 days) of flowering was presented by Sky Spur on local crab apple while minimum (92.0) days for fruit maturation were required by Royal Gala on MM.111. Maximum (112.5 g) fruit weight, total soluble solids (13.95%), total sugars (10.9 %) and reducing sugars (7.94%) were recorded for Starking Delicious on MM.111. On the other hand more pH (3.51) and ascorbic acid (9.2 %) content were recorded for Kala Kulu on crab apple. Red Chief found to be high yielding cultivar on MM.111 than crab apple while total sugars, TSS and average fruit weight were better for Starking Delicious. It was concluded that performance of apple cultivars were variable on both rootstocks. However, MM.111 proved better than local crab apple under prevailing conditions. (author)

  16. Controlled humidity gas circulators

    International Nuclear Information System (INIS)

    Gruner, S.M.

    1981-01-01

    A programmable circulator capable of regulating the humidity of a gas stream over a wide range of humidity is described. An optical dew-point hygrometer is used as a feedback element to control the addition or removal of water vapor. Typical regulation of the gas is to a dew-point temperature of +- 0.2 0 C and to an accuracy limited by the dew-point hygrometer

  17. Comment on "Donders, T.H. 2014. Middle Holocene humidity increase in Florida: climate or sea-level? Quaternary Science Reviews 103:170-174."

    Science.gov (United States)

    Glaser, Paul H.; Hansen, Barbara CS; Donovan, Joseph J.; Givnish, Thomas J.; Stricker, Craig A.; Volin, John C.

    2015-01-01

    Donders (2014) has recently proposed that the climate of Florida became progressively wetter over the past 5000 years in response to a marked strengthening of the El Niño regime. This reconstruction is largely based on a re-analysis of pollen records from regions north of Lake Okeechobee (Fig. 1) using a new set of pollen transfer functions. Donders concluded that a latitudinal gradient in precipitation prevailed across Florida since the mid Holocene, but the overall trend was toward progressively wetter conditions from 5000 cal BP to the present.

  18. Sensitivity Analysis of Snow Patterns in Swiss Ski Resorts to Shifts in Temperature, Precipitation and Humidity Under Condition of Climate Change

    Science.gov (United States)

    Uhlmann, B.; Goyette, S.; Beniston, M.

    2008-12-01

    The value of snow as a resource has considerably increased in Swiss mountain regions, in particular in the context of winter tourism. In the perspective of a warming climate, it is thus important to quantify the potential changes in snow amount and duration that could have large repercussions on the economy of ski resorts. Because of the fine spatial variability of snow, the use of a Surface Energy Balance Model (SEBM) is adequate to simulate local snow cover evolution. A perturbation method has been developed to generate plausible future meteorological input data required for SEBM simulations in order to assess the changes in snow cover patterns. Current and future snow depths have also been simulated within the ski areas themselves. The results show a large decrease of the snow depths and duration, even at high elevation in a warmer climate and emphasize the sensitivity of snow to topographical characteristics of the resorts. The study highlights the fact that not only the altitude of a domain but also its exposure, localization inland and slope gradients need to be taken into account when evaluating current and future snow depths. This method enables a precise assessment of the snow pattern over a small area.

  19. Seasonal Cycles of Oceanic Transports in the Eastern Subpolar North Atlantic

    Science.gov (United States)

    Gary, Stefan F.; Cunningham, Stuart A.; Johnson, Clare; Houpert, Loïc.; Holliday, N. Penny; Behrens, Erik; Biastoch, Arne; Böning, Claus W.

    2018-02-01

    The variability of the Atlantic Meridional Overturning Circulation (AMOC) may play a role in sea surface temperature predictions on seasonal to decadal time scales. Therefore, AMOC seasonal cycles are a potential baseline for interpreting predictions. Here we present estimates for the seasonal cycle of transports of volume, temperature, and freshwater associated with the upper limb of the AMOC in the eastern subpolar North Atlantic on the Extended Ellett Line hydrographic section between Scotland and Iceland. Due to weather, ship-based observations are primarily in summer. Recent glider observations during other seasons present an opportunity to investigate the seasonal variability in the upper layer of the AMOC. First, we document a new method to quality control and merge ship, float, and glider hydrographic observations. This method accounts for the different spatial sampling rates of the three platforms. The merged observations are used to compute seasonal cycles of volume, temperature, and freshwater transports in the Rockall Trough. These estimates are similar to the seasonal cycles in two eddy-resolving ocean models. Volume transport appears to be the primary factor modulating other Rockall Trough transports. Finally, we show that the weakest transports occur in summer, consistent with seasonal changes in the regional-scale wind stress curl. Although the seasonal cycle is weak compared to other variability in this region, the amplitude of the seasonal cycle in the Rockall Trough, roughly 0.5-1 Sv about a mean of 3.4 Sv, may account for up to 7-14% of the heat flux between Scotland and Greenland.

  20. Density of loose-fill insulation material exposed to cyclic humidity conditions

    DEFF Research Database (Denmark)

    Rasmussen, Torben Valdbjørn

    the granulated loose-fill material is exposed to a climate that is characterised as cyclic humidity conditions (a constant temperature and a relative humidity alternating between two predetermined constant relative humidity levels). A better understanding of the behaviour of granulated loose-fill material...

  1. Can Empirical Algorithms Successfully Estimate Aragonite Saturation State in the Subpolar North Atlantic?

    Directory of Open Access Journals (Sweden)

    Daniela Turk

    2017-12-01

    Full Text Available The aragonite saturation state (ΩAr in the subpolar North Atlantic was derived using new regional empirical algorithms. These multiple regression algorithms were developed using the bin-averaged GLODAPv2 data of commonly observed oceanographic variables [temperature (T, salinity (S, pressure (P, oxygen (O2, nitrate (NO3-, phosphate (PO43-, silicate (Si(OH4, and pH]. Five of these variables are also frequently observed using autonomous platforms, which means they are widely available. The algorithms were validated against independent shipboard data from the OVIDE2012 cruise. It was also applied to time series observations of T, S, P, and O2 from the K1 mooring (56.5°N, 52.6°W to reconstruct for the first time the seasonal variability of ΩAr. Our study suggests: (i linear regression algorithms based on bin-averaged carbonate system data can successfully estimate ΩAr in our study domain over the 0–3,500 m depth range (R2 = 0.985, RMSE = 0.044; (ii that ΩAr also can be adequately estimated from solely non-carbonate observations (R2 = 0.969, RMSE = 0.063 and autonomous sensor variables (R2 = 0.978, RMSE = 0.053. Validation with independent OVIDE2012 data further suggests that; (iii both algorithms, non-carbonate (MEF = 0.929 and autonomous sensors (MEF = 0.995 have excellent predictive skill over the 0–3,500 depth range; (iv that in deep waters (>500 m observations of T, S, and O2 may be sufficient predictors of ΩAr (MEF = 0.913; and (iv the importance of adding pH sensors on autonomous platforms in the euphotic and remineralization zone (<500 m. Reconstructed ΩAr at Irminger Sea site, and the K1 mooring in Labrador Sea show high seasonal variability at the surface due to biological drawdown of inorganic carbon during the summer, and fairly uniform ΩAr values in the water column during winter convection. Application to time series sites shows the potential for regionally tuned algorithms, but they need to be further compared against

  2. Overflow Water Pathways in the Subpolar North Atlantic Observed with Deep Floats

    Science.gov (United States)

    Bower, Amy; Furey, Heather; Lozier, Susan

    2017-04-01

    As part of the Overturning in the Subpolar North Atlantic Program (OSNAP), a total of 135 acoustically tracked RAFOS floats have been deployed in the deep boundary currents of the Iceland, Irminger and Labrador Basins, and in the Charlie-Gibbs Fracture Zone, to investigate the pathways of Iceland-Scotland Overflow Water (ISOW) and Denmark Strait Overflow Water (DSOW). Floats were released annually in 2014, 2015 and 2016 at depths between 1800 and 2800 m for two-year missions. The array of sound sources used for tracking was expanded from 10 to 13 moorings in 2016 when it was discovered that wintertime surface roughness was negatively impacting acoustic ranges. The floats from the first setting reveal several examples of persistent , deep coherent eddy motion, including a cyclonic eddy spinning off the tip of Eirik Ridge (southwest of Cape Farewell), a cyclonic eddy in the northeastern Labrador Basin near where anticyclonic Irminger Rings are formed, and an anticyclonic eddy under the North Atlantic Current (NAC) in the central Iceland Basin. A consistent region of boundary-interior exchange was observed near Hamilton Bank on the western boundary of the Labrador Sea. Deep cyclonic recirculation gyres are revealed in all three basins. Floats released in the southward-flowing deep boundary current over the eastern flank of the Reykjanes Ridge show that shallower layers of ISOW peel off to the west and cross the Ridge into the Irminger Basin through various gaps south of 60°N, including the Bight Fracture Zone. These floats tend to turn northward and continue along the slope in the Irminger Basin. Interestingly, floats released at the ISOW level in the CGFZ did not turn into the Irminger Basin as often depicted in deep circulation schematics, but rather drifted west-northwestward toward the Labrador Sea, or eddied around west of the CGFZ and (in some cases) turned southward. This result is consistent with some previous hydrographic and high-resolution model results

  3. Global response to solar radiation absorbed by phytoplankton in a coupled climate model

    Energy Technology Data Exchange (ETDEWEB)

    Patara, Lavinia [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Helmholtz Centre for Ocean Research Kiel (GEOMAR), Kiel (Germany); Vichi, Marcello; Masina, Simona [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Istituto Nazionale di Geofisica e Vulcanologia (INGV), Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Fogli, Pier Giuseppe [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Manzini, Elisa [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Max-Planck-Institut fuer Meteorologie, Hamburg (Germany)

    2012-10-15

    The global climate response to solar radiation absorbed by phytoplankton is investigated by performing multi-century simulations with a coupled ocean-atmosphere-biogeochemistry model. The absorption of solar radiation by phytoplankton increases radiative heating in the near-surface ocean and raises sea surface temperature (SST) by overall {approx}0.5 C. The resulting increase in evaporation enhances specific atmospheric humidity by 2-5%, thereby increasing the Earth's greenhouse effect and the atmospheric temperatures. The Hadley Cell exhibits a weakening and poleward expansion, therefore reducing cloudiness at subtropical-middle latitudes and increasing it at tropical latitudes except near the Equator. Higher SST at polar latitudes reduces sea ice cover and albedo, thereby increasing the high-latitude ocean absorption of solar radiation. Changes in the atmospheric baroclinicity cause a poleward intensification of mid-latitude westerly winds in both hemispheres. As a result, the North Atlantic Ocean meridional overturning circulation extends more northward, and the equatorward Ekman transport is enhanced in the Southern Ocean. The combination of local and dynamical processes decreases upper-ocean heat content in the Tropics and in the subpolar Southern Ocean, and increases it at middle latitudes. This study highlights the relevance of coupled ocean-atmosphere processes in the global climate response to phytoplankton solar absorption. Given that simulated impacts of phytoplankton on physical climate are within the range of natural climate variability, this study suggests the importance of phytoplankton as an internal constituent of the Earth's climate and its potential role in participating in its long-term climate adjustments. (orig.)

  4. Global response to solar radiation absorbed by phytoplankton in a coupled climate model

    International Nuclear Information System (INIS)

    Patara, Lavinia; Vichi, Marcello; Masina, Simona; Fogli, Pier Giuseppe; Manzini, Elisa

    2012-01-01

    The global climate response to solar radiation absorbed by phytoplankton is investigated by performing multi-century simulations with a coupled ocean-atmosphere-biogeochemistry model. The absorption of solar radiation by phytoplankton increases radiative heating in the near-surface ocean and raises sea surface temperature (SST) by overall ∼0.5 C. The resulting increase in evaporation enhances specific atmospheric humidity by 2-5%, thereby increasing the Earth's greenhouse effect and the atmospheric temperatures. The Hadley Cell exhibits a weakening and poleward expansion, therefore reducing cloudiness at subtropical-middle latitudes and increasing it at tropical latitudes except near the Equator. Higher SST at polar latitudes reduces sea ice cover and albedo, thereby increasing the high-latitude ocean absorption of solar radiation. Changes in the atmospheric baroclinicity cause a poleward intensification of mid-latitude westerly winds in both hemispheres. As a result, the North Atlantic Ocean meridional overturning circulation extends more northward, and the equatorward Ekman transport is enhanced in the Southern Ocean. The combination of local and dynamical processes decreases upper-ocean heat content in the Tropics and in the subpolar Southern Ocean, and increases it at middle latitudes. This study highlights the relevance of coupled ocean-atmosphere processes in the global climate response to phytoplankton solar absorption. Given that simulated impacts of phytoplankton on physical climate are within the range of natural climate variability, this study suggests the importance of phytoplankton as an internal constituent of the Earth's climate and its potential role in participating in its long-term climate adjustments. (orig.)

  5. Hands-on Humidity.

    Science.gov (United States)

    Pankiewicz, Philip R.

    1992-01-01

    Presents five hands-on activities that allow students to detect, measure, reduce, and eliminate moisture. Students make a humidity detector and a hygrometer, examine the effects of moisture on different substances, calculate the percent of water in a given food, and examine the absorption potential of different desiccants. (MDH)

  6. Ambient humidity and the skin: the impact of air humidity in healthy and diseased states.

    Science.gov (United States)

    Goad, N; Gawkrodger, D J

    2016-08-01

    Humidity, along with other climatic factors such as temperature and ultraviolet radiation, can have an important impact on the skin. Limited data suggest that external humidity influences the water content of the stratum corneum. An online literature search was conducted through Pub-Med using combinations of the following keywords: skin, skin disease, humidity, dermatoses, dermatitis, eczema, and mist. Publications included in this review were limited to (i) studies in humans or animals, (ii) publications showing relevance to the field of dermatology, (iii) studies published in English and (iv) publications discussing humidity as an independent influence on skin function. Studies examining environmental factors as composite influences on skin health are only included where the impact of humidity on the skin is also explored in isolation of other environmental factors. A formal systematic review was not feasible for this topic due to the heterogeneity of the available research. Epidemiological studies indicated an increase in eczema with low internal (indoors) humidity and an increase in eczema with external high humidity. Other studies suggest that symptoms of dry skin appear with low humidity internal air-conditioned environments. Murine studies determined that low humidity caused a number of changes in the skin, including the impairment of the desquamation process. Studies in humans demonstrated a reduction in transepidermal water loss (TEWL) (a measure of the integrity of the skin's barrier function) with low humidity, alterations in the water content in the stratum corneum, decreased skin elasticity and increased roughness. Intervention with a humidifying mist increased the water content of the stratum corneum. Conversely, there is some evidence that low humidity conditions can actually improve the barrier function of the skin. Ambient relative humidity has an impact on a range of parameters involved in skin health but the literature is inconclusive. Further

  7. Methods of humidity determination Part II: Determination of material humidity

    OpenAIRE

    Rübner, Katrin; Balköse, Devrim; Robens, E.

    2008-01-01

    Part II covers the most common methods of measuring the humidity of solid material. State of water near solid surfaces, gravimetric measurement of material humidity, measurement of water sorption isotherms, chemical methods for determination of water content, measurement of material humidity via the gas phase, standardisation, cosmonautical observations are reviewed.

  8. Statistical analysis of the effects of relative humidity and temperature ...

    African Journals Online (AJOL)

    Meteorological data from the Department of Satellite Application Facility on Climate Monitoring (CMSAF), DWD Germany have been used to study and investigate the effect of relative humidity and temperature on refractivity in twenty six locations grouped into for climatic regions aloft Nigeria (Coastal, Guinea savannah, ...

  9. Strategies for humidity control

    Energy Technology Data Exchange (ETDEWEB)

    Baumgarth, S

    1987-01-01

    Humidity and temperature control in air-conditioning systems mostly involves coupled closed-loop control circuits. The author discusses their uncoupling and resulting consequences as well as energy-optimized control of recirculation air flaps or enthalpy recovering systems (h-x control) in detail. Special reference is made of the application of the DDC technology and its scope, limits and preconditions. In conclusions, the author presents pertinent measurement results. (orig.).

  10. Seasonally warmer and humid climates in a lower paleolatitude position of southern Brazil (Paraná Basin): new findings of the Lueckisporites virkkiae zone (late Cisuralian-Guadalupian) in the Serra do Rio do Rastro and neighboring localities

    Science.gov (United States)

    di Pasquo, Mercedes; Souza, Paulo A.; Kavali, Pauline Sabina; Felix, Cristina

    2018-03-01

    First palynological information from surface samples of the Serra Alta and Rio do Rasto formations (Passa Dois Group, Paraná Basin), exposed in the Serra do Rio do Rastro (White's Column) and Urubici regions in Santa Catarina State (Brazil) is presented. The Serra Alta Formation is transitionally deposited over the Irati Formation, which is constrained to the late Artinskian/Kungurian by different paleontological and radiometric data. Twelve productive samples (of forty) yielded fairly well preserved palynomorphs, dominated by striate and non striate bisaccate and asaccate pollen grains and subordinated trilete and monolete spores, monosaccate pollen grains and Botryococcus. Diagnostic species of the Lueckisporites virkkiae Zone (Artinskian-Guadalupian) in the Paraná Basin are recorded along with few species of Guadalupian-Lopingian age (e.g. Cladaitina veteadensis, Guttulapollenites hannonicus, Lophotriletes parryensis, Protohaploxypinus microcorpus, Staurosaccites quadrifidus, Weylandites cincinnatus). They support a Kungurian-?Roadian age for the Serra Alta, and a Capitanian (?Lopingian) age for the Rio do Rasto formations. Four samples from the Sete Quedas outcrop yielded scarce and poorly preserved specimens of Lueckisporites likely due to weathering. A statistic comparison among our assemblages and selected Permian palynozones and palynofloras from South America supports a closer correlation with the La Veteada Formation (Guadalupian-Lopingian) from western Argentina due to common occurrence of all the species, and with the Striatites Zone (late Artinskian-Kungurian) of the Chacoparaná Basin, and the I-S Zone Melo Formation in Uruguay. The botanical affinities of the palynomorphs from both assemblages indicate the presence of spores of hygro-mesophytic affinities along with meso-xerophyle pollen grains, which is in agreement with seasonally warmer and humid climates favored by a lower paleolatitude position. The presence of pyrite in some of the miospore

  11. Comparative analysis of the heat transfer rates in constant (CAV) and variable (VAV) volumes type multi zone acclimation system operating in hot and humid climate; Analise comparativa das taxas transferencia de calor em sistemas de climatizacao do tipo volume de ar constante (CAV) e volume de ar variavel (VAV) multizona operando em clima quente e umido

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Cesar A.G.; Correa, Jorge E. [Para Univ., Belem (Brazil). Centro Tecnologico. Dept. de Engenharia Mecanica]. E-mails: gsantos@ufpa.br; jecorrea@amazon.com.br

    2000-07-01

    This work performs a comparative analysis among the constant and variable air volume multi zones acclimation systems, used for provide the thermal comfort in buildings. The work used the simulation HVAC2KIT computer program. The results of sensible and latent heats transfer rates on the cooling and dehumidification, inflating fan capacity, and heat transfer on the final heating condenser were obtained and analysed for the climate conditions of the Brazilian city of Belem from Para State, presenting hot and humid climate during all the year.

  12. Analysis of air temperature and relative humidity: study of microclimates

    OpenAIRE

    Elis Dener Lima Alves; Marcelo Sacardi Biudes

    2012-01-01

    Understanding the variability of climate elements in time and space is fundamental to the knowledge of the dynamics of microclimate. Thus, the objective was to analyze the variability of air temperature and relative humidity on the Cuiabá campus of the Federal University of Mato Grosso, and, through the clustering technique, to analyze the formation of groups to propose a zoning microclimate in the area study. To this end, collection data of air temperature and relative humidity at 15 points ...

  13. Low-cost personal cooling in hot humid offices

    DEFF Research Database (Denmark)

    Gunnarsen, Lars Bo; Santos, A.

    This report presents a low cost solution to avoid heat stress in a hot and humid environment based on a solar powered drying of supply air. The air drying facilities and a validation of the benefits through comprehensive human exposure studies are described. The study represents an example...... of applied participative research performed in a developing country. The report may be used as a background for the improvement of the indoor climate in poor, hot and humid regions without increased use of electricity....

  14. Changes of pressure and humidity affect olfactory function.

    Science.gov (United States)

    Kuehn, Michael; Welsch, Heiko; Zahnert, Thomas; Hummel, Thomas

    2008-03-01

    The present study aimed at investigating the question whether olfactory function changes in relation to barometric pressure and humidity. Using climate chambers, odor threshold and discrimination for butanol were tested in 75 healthy volunteers under hypobaric and hyperbaric, and different humidity conditions. Among other effects, olfactory sensitivity at threshold level, but not suprathreshold odor discrimination, was impaired in a hypobaric compared to a hyperbaric milieu, and thresholds were lower in humid, compared to relatively dry conditions. In conclusion, environmental conditions modulate the sense of smell, and may, consecutively, influence results from olfactory tests.

  15. Humidity sensing in insects-from ecology to neural processing.

    Science.gov (United States)

    Enjin, Anders

    2017-12-01

    Humidity is an omnipresent climatic factor that influences the fitness, reproductive behavior and geographic distribution of animals. Insects in particular use humidity cues to navigate the environment. Although the sensory neurons of this elusive sense were first described more than fifty years ago, the transduction mechanism of humidity sensing (hygrosensation) remains unknown. Recent work has uncovered some of the key molecules involved, opening up for novel approaches to study hygrosensory transduction. In this review, I will discuss this progress made toward understanding hygrosensation in insects. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Sea surface temperature and sea ice variability in the subpolar North Atlantic from explosive volcanism of the late thirteenth century

    DEFF Research Database (Denmark)

    Sicre, M. -A.; Khodri, M.; Mignot, J.

    2013-01-01

    In this study, we use IP25 and alkenone biomarker proxies to document the subdecadal variations of sea ice and sea surface temperature in the subpolar North Atlantic induced by the decadally paced explosive tropical volcanic eruptions of the second half of the thirteenth century. The short-and long......-term evolutions of both variables were investigated by cross analysis with a simulation of the IPSL-CM5A LR model. Our results show short-term ocean cooling and sea ice expansion in response to each volcanic eruption. They also highlight that the long response time of the ocean leads to cumulative surface cooling...... and subsurface heat buildup due to sea ice capping. As volcanic forcing relaxes, the surface ocean rapidly warms, likely amplified by subsurface heat, and remains almost ice free for several decades....

  17. Climate

    International Nuclear Information System (INIS)

    Fellous, J.L.

    2005-02-01

    This book starts with a series of about 20 preconceived ideas about climate and climatic change and analyses each of them in the light of the present day knowledge. Using this approach, it makes a status of the reality of the climatic change, of its causes and of the measures to be implemented to limit its impacts and reduce its most harmful consequences. (J.S.)

  18. Temperature and Humidity Effects on Hospital Morbidity in Darwin, Australia.

    Science.gov (United States)

    Goldie, James; Sherwood, Steven C; Green, Donna; Alexander, Lisa

    2015-01-01

    Many studies have explored the relationship between temperature and health in the context of a changing climate, but few have considered the effects of humidity, particularly in tropical locations, on human health and well-being. To investigate this potential relationship, this study assessed the main and interacting effects of daily temperature and humidity on hospital admission rates for selected heat-relevant diagnoses in Darwin, Australia. Univariate and bivariate Poisson generalized linear models were used to find statistically significant predictors and the admission rates within bins of predictors were compared to explore nonlinear effects. The analysis indicated that nighttime humidity was the most statistically significant predictor (P < 0.001), followed by daytime temperature and average daily humidity (P < 0.05). There was no evidence of a significant interaction between them or other predictors. The nighttime humidity effect appeared to be strongly nonlinear: Hot days appeared to have higher admission rates when they were preceded by high nighttime humidity. From this analysis, we suggest that heat-health policies in tropical regions similar to Darwin need to accommodate the effects of temperature and humidity at different times of day. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  19. Humidity Graphs for All Seasons.

    Science.gov (United States)

    Esmael, F.

    1982-01-01

    In a previous article in this journal (Vol. 17, p358, 1979), a wet-bulb depression table was recommended for two simple experiments to determine relative humidity. However, the use of a graph is suggested because it gives the relative humidity directly from the wet and dry bulb readings. (JN)

  20. Humidity requirements in WSCF Laboratories

    International Nuclear Information System (INIS)

    Evans, R.A.

    1994-01-01

    The purpose of this paper is to develop and document a position on Relative Humidity (RH) requirements in the WSCF Laboratories. A current survey of equipment vendors for Organic, Inorganic and Radiochemical laboratories indicate that 25% - 80% relative humidity may meet the environmental requirements for safe operation and protection of all the laboratory equipment

  1. Hydrological drought and wildfire in the humid tropics

    NARCIS (Netherlands)

    Taufik, Muh

    2017-01-01

    Drought is a recurrent hazard, which has happened throughout human history, and it is anticipated to become more severe in multiple regions across the world. Drought occurs in all climate regimes from humid to dry and from hot to cold. Drought is often viewed through its impact on environment and

  2. Metagenomic Analysis of Subtidal Sediments from Polar and Subpolar Coastal Environments Highlights the Relevance of Anaerobic Hydrocarbon Degradation Processes

    Energy Technology Data Exchange (ETDEWEB)

    Espinola, Fernando J.; Dionisi, Hebe M.; Borglin, Sharon; Brislawn, Colin J.; Jansson, Janet K.; Mac Cormack, Walter P.; Carroll, Jolynn; Sjoling, Sara; Lozada , Mariana

    2018-01-02

    In this work, we analyzed the community structure and metabolic potential of sediment microbial communities in high-latitude coastal environments subjected to low to moderate levels of chronic pollution. Subtidal sediments from four low-energy inlets located in polar and subpolar regions from both Hemispheres were analyzed using large-scale 16S rRNA gene and metagenomic sequencing. Communities showed high diversity (Shannon’s index 6.8 to 10.2), with distinct phylogenetic structures (<40% shared taxa at the Phylum level among regions) but similar metabolic potential in terms of sequences assigned to KOs. Environmental factors (mainly salinity, temperature, and in less extent organic pollution) were drivers of both phylogenetic and functional traits. Bacterial taxa correlating with hydrocarbon pollution included families of anaerobic or facultative anaerobic lifestyle, such as Desulfuromonadaceae, Geobacteraceae, and Rhodocyclaceae. In accordance, biomarker genes for anaerobic hydrocarbon degradation (bamA, ebdA, bcrA, and bssA) were prevalent, only outnumbered by alkB, and their sequences were taxonomically binned to the same bacterial groups. BssA-assigned metagenomic sequences showed an extremely wide diversity distributed all along the phylogeny known for this gene, including bssA sensu stricto, nmsA, assA, and other clusters from poorly or not yet described variants. This work increases our understanding of microbial community patterns in cold coastal sediments, and highlights the relevance of anaerobic hydrocarbon degradation processes in subtidal environments.

  3. Climatic impact of volcanic eruptions

    Science.gov (United States)

    Rampino, Michael R.

    1991-01-01

    Studies have attempted to 'isolate' the volcanic signal in noisy temperature data. This assumes that it is possible to isolate a distinct volcanic signal in a record that may have a combination of forcings (ENSO, solar variability, random fluctuations, volcanism) that all interact. The key to discovering the greatest effects of volcanoes on short-term climate may be to concentrate on temperatures in regions where the effects of aerosol clouds may be amplified by perturbed atmospheric circulation patterns. This is especially true in subpolar and midlatitude areas affected by changes in the position of the polar front. Such climatic perturbation can be detected in proxy evidence such as decrease in tree-ring widths and frost rings, changes in the treeline, weather anomalies, severity of sea-ice in polar and subpolar regions, and poor grain yields and crop failures. In low latitudes, sudden temperature drops were correlated with the passage overhead of the volcanic dust cloud (Stothers, 1984). For some eruptions, such as Tambora, 1815, these kinds of proxy and anectdotal information were summarized in great detail in a number of papers and books (e.g., Post, 1978; Stothers, 1984; Stommel and Stommel, 1986; C. R. Harrington, in press). These studies lead to the general conclusion that regional effects on climate, sometimes quite severe, may be the major impact of large historical volcanic aerosol clouds.

  4. Climatic classification of the Karst

    International Nuclear Information System (INIS)

    Eslava Ramirez Jesus Antonio; Bahamon Ayala, Sandra Marcela; Lopez Romero Maria Ines

    2000-01-01

    Climate is one the main factors in forming or modifying Karsts, or its resulting forms. The determining climatic elements of Karst characteristics are humidity, air circulation and temperature. Many Karstic processes show characteristics corresponding to a given climate sequence. In the present article we discuss the relation between climate and Karst as well as a climate classification based on the structure of the Karsts

  5. Time dependency of the prediction skill for the North Atlantic subpolar gyre in initialized decadal hindcasts with MPI-ESM

    Science.gov (United States)

    Brune, Sebastian; Düsterhus, Andre; Pohlmann, Holger; Müller, Wolfgang; Baehr, Johanna

    2017-04-01

    We analyze the time dependency of decadal hindcast skill in the North Atlantic subpolar gyre within the time period 1961-2013. We compare anomaly correlation coefficients and interquartile ranges of total upper ocean heat content and sea surface temperature for three differently initialized sets of hindcast simulations with the global coupled model MPI-ESM. All initializations use weakly coupled assimilation with the same full-field nudging in the atmospheric component and different assimilation techniques for oceanic temperature and salinity: (1) ensemble Kalman filter assimilating EN4 and HadISST observations, (2) nudging of anomalies to ORAS4 reanalysis, (3) nudging of full values to ORAS4 reanalysis. We find that hindcast skill depends strongly on the evaluation time period, with higher hindcast skill during strong multiyear trends and lower hindcast skill in the absence of such trends. While there may only be small differences between the prediction systems in the analysis focusing on the entire hindcast period, these differences between the hindcast systems are much more pronounced when investigating any 20-year subperiod within the entire hindcast period. For the ensemble Kalman filter high skill in the assimilation experiment is generally linked to high skill in the initialized hindcasts. Such direct link does not seem to exist in the hindcasts initialized by either nudged system. In the ensemble Kalman filter initialized hindcasts, we find significant hindcast skill for up to 5 to 8 lead years, except for the 1970s. In the nudged system initialized hindcasts, hindcast skill is consistently diminished in lead years 2 and 3 with lowest skill in the 1970s as well. Overall, we find that a model-consistent assimilation technique can improve hindcast skill. Further, the evaluation of 20 year subperiods within the full hindcast period provides essential insights to judge the success of both the assimilation and the subsequent hindcast skill.

  6. Trends in continental temperature and humidity directly linked to ocean warming.

    Science.gov (United States)

    Byrne, Michael P; O'Gorman, Paul A

    2018-05-08

    In recent decades, the land surface has warmed substantially more than the ocean surface, and relative humidity has fallen over land. Amplified warming and declining relative humidity over land are also dominant features of future climate projections, with implications for climate-change impacts. An emerging body of research has shown how constraints from atmospheric dynamics and moisture budgets are important for projected future land-ocean contrasts, but these ideas have not been used to investigate temperature and humidity records over recent decades. Here we show how both the temperature and humidity changes observed over land between 1979 and 2016 are linked to warming over neighboring oceans. A simple analytical theory, based on atmospheric dynamics and moisture transport, predicts equal changes in moist static energy over land and ocean and equal fractional changes in specific humidity over land and ocean. The theory is shown to be consistent with the observed trends in land temperature and humidity given the warming over ocean. Amplified land warming is needed for the increase in moist static energy over drier land to match that over ocean, and land relative humidity decreases because land specific humidity is linked via moisture transport to the weaker warming over ocean. However, there is considerable variability about the best-fit trend in land relative humidity that requires further investigation and which may be related to factors such as changes in atmospheric circulations and land-surface properties.

  7. Ultrahigh humidity sensitivity of graphene oxide.

    Science.gov (United States)

    Bi, Hengchang; Yin, Kuibo; Xie, Xiao; Ji, Jing; Wan, Shu; Sun, Litao; Terrones, Mauricio; Dresselhaus, Mildred S

    2013-01-01

    Humidity sensors have been extensively used in various fields, and numerous problems are encountered when using humidity sensors, including low sensitivity, long response and recovery times, and narrow humidity detection ranges. Using graphene oxide (G-O) films as humidity sensing materials, we fabricate here a microscale capacitive humidity sensor. Compared with conventional capacitive humidity sensors, the G-O based humidity sensor has a sensitivity of up to 37800% which is more than 10 times higher than that of the best one among conventional sensors at 15%-95% relative humidity. Moreover, our humidity sensor shows a fast response time (less than 1/4 of that of the conventional one) and recovery time (less than 1/2 of that of the conventional one). Therefore, G-O appears to be an ideal material for constructing humidity sensors with ultrahigh sensitivity for widespread applications.

  8. Impact of individually controlled facially applied air movement on perceived air quality at high humidity

    Energy Technology Data Exchange (ETDEWEB)

    Skwarczynski, M.A. [Faculty of Environmental Engineering, Institute of Environmental Protection Engineering, Department of Indoor Environment Engineering, Lublin University of Technology, Lublin (Poland); International Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, Copenhagen (Denmark); Melikov, A.K.; Lyubenova, V. [International Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, Copenhagen (Denmark); Kaczmarczyk, J. [Faculty of Energy and Environmental Engineering, Department of Heating, Ventilation and Dust Removal Technology, Silesian University of Technology, Gliwice (Poland)

    2010-10-15

    The effect of facially applied air movement on perceived air quality (PAQ) at high humidity was studied. Thirty subjects (21 males and 9 females) participated in three, 3-h experiments performed in a climate chamber. The experimental conditions covered three combinations of relative humidity and local air velocity under a constant air temperature of 26 C, namely: 70% relative humidity without air movement, 30% relative humidity without air movement and 70% relative humidity with air movement under isothermal conditions. Personalized ventilation was used to supply room air from the front toward the upper part of the body (upper chest, head). The subjects could control the flow rate (velocity) of the supplied air in the vicinity of their bodies. The results indicate an airflow with elevated velocity applied to the face significantly improves the acceptability of the air quality at the room air temperature of 26 C and relative humidity of 70%. (author)

  9. Humidity evolution (breathing effect) in enclosures with electronics

    DEFF Research Database (Denmark)

    Hygum, Morten Arnfeldt; Popok, Vladimir

    2015-01-01

    Packaging and enclosures used for protecting power electronics operating outdoors are designed to withstand the local climatic and environmental changes. Hermetic enclosures are expensive and therefore other solutions for protecting the electronics from a harsh environment are required. One...... of the dangerous parameters is high humidity of air. Moisture can inevitable reach the electronics either due to diffusion through the wall of an enclosure or small holes, which are designed for electrical or other connections. A driving force for humid air movement is the temperature difference between...... the operating electronics and the surrounding environment. This temperature, thus, gives rise to a natural convection, which we also refer to as breathing. Robust and intelligent enclosure designs must account for this breathing as it can significantly change the humidity distribution in the enclosure...

  10. Air humidity requirements for human comfort

    DEFF Research Database (Denmark)

    Toftum, Jørn; Fanger, Povl Ole

    1999-01-01

    level near 100% rh. For respiratory comfort are the requirements much more stringent and results in lower permissible indoor air humidities. Compared with the upper humidity limit specified in existing thermal comfort standards, e.g. ASHRAE Addendum 55a, the humidity limit based on skin humidity......Upper humidity limits for the comfort zone determined from two recently presented models for predicting discomfort due to skin humidity and insufficient respiratory cooling are proposed. The proposed limits are compared with the maximum permissible humidity level prescribed in existing standards...... for the thermal indoor environment. The skin humidity model predicts discomfort as a function of the relative humidity of the skin, which is determined by existing models for human heat and moisture transfer based on environmental parameters, clothing characteristics and activity level. The respiratory model...

  11. Impact of Ambient Humidity on Child Health: A Systematic Review

    Science.gov (United States)

    Gao, Jinghong; Sun, Yunzong; Lu, Yaogui; Li, Liping

    2014-01-01

    Background and Objectives Changes in relative humidity, along with other meteorological factors, accompany ongoing climate change and play a significant role in weather-related health outcomes, particularly among children. The purpose of this review is to improve our understanding of the relationship between ambient humidity and child health, and to propose directions for future research. Methods A comprehensive search of electronic databases (PubMed, Medline, Web of Science, ScienceDirect, OvidSP and EBSCO host) and review of reference lists, to supplement relevant studies, were conducted in March 2013. All identified records were selected based on explicit inclusion criteria. We extracted data from the included studies using a pre-designed data extraction form, and then performed a quality assessment. Various heterogeneities precluded a formal quantitative meta-analysis, therefore, evidence was compiled using descriptive summaries. Results Out of a total of 3797 identified records, 37 papers were selected for inclusion in this review. Among the 37 studies, 35% were focused on allergic diseases and 32% on respiratory system diseases. Quality assessment revealed 78% of the studies had reporting quality scores above 70%, and all findings demonstrated that ambient humidity generally plays an important role in the incidence and prevalence of climate-sensitive diseases among children. Conclusions With climate change, there is a significant impact of ambient humidity on child health, especially for climate-sensitive infectious diseases, diarrhoeal diseases, respiratory system diseases, and pediatric allergic diseases. However, some inconsistencies in the direction and magnitude of the effects are observed. PMID:25503413

  12. Humidity Buildup in Electronic Enclosures Exposed to Constant Conditions

    DEFF Research Database (Denmark)

    Conseil, Helene; Staliulionis, Zygimantas; Jellesen, Morten Stendahl

    2017-01-01

    Electronic components and devices are exposed to a wide variety of climatic conditions, therefore the protection of electronic devices from humidity is becoming a critical factor in the system design. The ingress of moisture into typical electronic enclosures has been studied with defined paramet....... The moisture buildup inside the enclosure has been simulated using an equivalent RC circuit consisting of variables like controlled resistors and capacitors to describe the diffusivity, permeability, and storage in polymers....

  13. Cross-Sensitivity Of Aethalometer Measurements To Relative Humidity

    Energy Technology Data Exchange (ETDEWEB)

    Hannemann, A.; Baltensperger, U.; Weingartner, E.

    2005-03-01

    Absorptive light reduction by atmospheric aerosols is important with respect to their climate forcing. An instrument to measure light absorption is the aethalometer, which is routinely used to measure the attenuation of light transmitted through aerosol-laden fibre filters. Measurements have shown that the condensable gases require a correction for artefacts. We present the first corrections for hydrophobic Palas soot-laden filters for the whole humidity range, enhancing the accuracy of aethalometer datasets. (author)

  14. Large bio-geographical shifts in the north-eastern Atlantic Ocean: From the subpolar gyre, via plankton, to blue whiting and pilot whales

    Science.gov (United States)

    Hátún, H.; Payne, M. R.; Beaugrand, G.; Reid, P. C.; Sandø, A. B.; Drange, H.; Hansen, B.; Jacobsen, J. A.; Bloch, D.

    2009-03-01

    Pronounced changes in fauna, extending from the English Channel in the south to the Barents Sea in the north-east and off Greenland in the north-west, have occurred in the late 1920s, the late 1960s and again in the late 1990s. We attribute these events to exchanges of subarctic and subtropical water masses in the north-eastern North Atlantic Ocean, associated with changes in the strength and extent of the subpolar gyre. These exchanges lead to variations in the influence exerted by the subarctic or Lusitanian biomes on the intermediate faunistic zone in the north-eastern Atlantic. This strong and persistent bottom-up bio-physical link is demonstrated using a numerical ocean general circulation model and data on four trophically connected levels in the food chain - phytoplankton, zooplankton, blue whiting, and pilot whales. The plankton data give a unique basin-scale depiction of these changes, and a long pilot whale record from the Faroe Islands offers an exceptional temporal perspective over three centuries. Recent advances in simulating the dynamics of the subpolar gyre suggests a potential for predicting the distribution of the main faunistic zones in the north-eastern Atlantic a few years into the future, which might facilitate a more rational management of the commercially important fisheries in this region.

  15. Uncertainties in downscaled relative humidity for a semi-arid region ...

    Indian Academy of Sciences (India)

    variables are extracted from the (1) National Centers for Environmental Prediction ... and (2) simulations of the third generation Canadian Coupled Global Climate ... Ef, MAE and P. Cumulative distribution functions were prepared from the ... Climate change; downscaling; hydroclimatology; relative humidity; multi-step linear ...

  16. High temperature humidity sensing materials

    International Nuclear Information System (INIS)

    Tsai, P.P.; Tanase, S.; Greenblatt, M.

    1989-01-01

    This paper reports on new proton conducting materials prepared and characterized for potential applications in humidity sensing at temperatures higher than 100 degrees C by complex impedance or galvanic cell type techniques. Calcium metaphosphate, β-Ca(PO 3 ) 2 as a galvanic cell type sensor material yields reproducible signals in the range from 5 to 200 mm Hg water vapor pressure at 578 degrees C, with short response time (∼ 30 sec). Polycrystalline samples of α-Zr(HPO 4 ) 2 and KMo 3 P 5.8 Si 2 O 25 , and the gel converted ceramic, 0.10Li 2 O-0.25P 2 O 5 -0.65SiO 2 as impedance sensor materials show decreases in impedance with increasing humidity in the range from 9 mm Hg to 1 atm water vapor pressure at 179 degrees C

  17. Energy- and humidity-budget of the non-hydrostatic mesoscale model GESIMA by nesting into the regional climate model REMO; Energie- und Feuchtehaushalt im nichthydrostatischen Mesoskalamodell GESIMA bei Nestung in das Regionalklimamodell REMO

    Energy Technology Data Exchange (ETDEWEB)

    Horneffer, K. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Gewaesserphysik]|[Hamburg Univ. (Germany). Fachbereich 15 - Geowissenschaften

    1997-12-31

    The `Geesthacht Simulationsmodel of the Atmosphere` (GESIMA) was nested into the `Regional Climate Model` (REMO). Exemplary studies prove that the presented nesting scheme is suitable to resolve subscale phenomena in the regional climate model. Some results of simulations above the island Gotland in the Baltic Sea were presented. The mesoscale model GESIMA could now be used to analyze real synoptic weather situations. (orig.) [Deutsch] Das Geesthachter Simulationsmodell der Atmosphaere (GESIMA) wird in das Regionalklimamodell (REMO) genestet. Beispielhafte Untersuchungen zeigen, dass mit der genesteten Modellversion subskalige Effekte, die durch das grobe Raster des Regionalklimamodells fallen, aufgeloest werden. Dies wird anhand von Simulationen ueberprueft. Hauptuntersuchungsgegenstand ist die Insel Gotland in der Ostsee. Duch die Nestung kann das Mesoskalamodell fuer tatsaechliche synoptische Situationen eingesetzt werden. (orig.)

  18. Coexistence of Dunes and Humid Conditions at Titan's Tropics

    Science.gov (United States)

    Radebaugh, Jani; Lorenz, R. D.; Lunine, J. I.; Kirk, R. L.; Ori, G. G.; Farr, T. G.; Malaska, M.; Le Gall, A.; Liu, Z. Y. C.; Encrenaz, P. J.; Paillou, P.; Hayes, A.; Lopes, R. M. C.; Turtle, E. P.; Wall, S. D.; Stofan, E. R.; Wood, C. A.; Cassini RADAR Team

    2012-10-01

    At Titan's equatorial latitudes there are tens of thousands of dunes, a landform typical of desert environments where sand does not become anchored by vegetation or fluids. Model climate simulations predict generally dry conditions at the equator and humid conditions near the poles of Titan, where lakes of methane/ethane are found. However, moderate relative methane humidity was observed at the Huygens landing site, recent rainfall was seen by Cassini ISS near the Belet Sand Sea, and a putative transient lake in Shangri-La was observed by Cassini VIMS, all of which indicate abundant fluids may be present, at least periodically, at Titan's equatorial latitudes. Terrestrial observations and studies demonstrate dunes can exist and migrate in conditions of high humidity. Active dunes are found in humid climates, indicating the movement of sand is not always prohibited by the presence of fluids. Sand mobility is related to precipitation, evaporation and wind speed and direction. If dune surfaces become wetted by rainfall or rising subsurface fluids, they can become immobilized. However, winds can act to dry the uppermost layers, freeing sands for saltation and enabling dune migration in wet conditions. Active dunes are found in tropical NE Brazil and NE Australia, where there are alternating dry and wet periods, a condition possible for Titan's tropics. Rising and falling water levels lead to the alteration of dune forms, mainly from being anchored by vegetation, but also from cementation by carbonates or clays. Studies of Titan's dunes, which could undergo anchoring of organic sediments by hydrocarbon fluids, could inform the relative strength of vegetation vs. cementation at humid dune regions on Earth. Furthermore, a comprehensive survey of dune morphologies near regions deemed low by SARTopo and stereo, where liquids may collect in wet conditions, could reveal if bodies of liquid have recently existed at Titan's tropics.

  19. Punctuated Sediment Input into Small Subpolar Ocean Basins During Heinrich Events and Preservation in the Stratigraphic Record

    Science.gov (United States)

    Hesse, R.

    2006-12-01

    Small subpolar ocean basins such as the Labrador Sea received a major portion (25%) of their sediment fill during the Pleistocene glaciations (less than 5% of the basin's lifetime), but the timing of sediment supply to the basin remained essentially unknown until recently. Discovery of the hitherto little known depositional facies of fine-grained lofted sediment suggests that the main sediment input into the basin was not coupled to major glacial cycles and associated sea-level changes but was related to Heinrich events. Heinrich events are known as Late Pleistocene ice-rafting episodes of unparalleled intensity in the North Atlantic that were associated with major melt-water discharge pulses and, as it appears now, also were the times of the main sediment delivery to the basin. The facies of lofted sediment consists of stacked layers of graded muds that contain ice-rafted debris (IRD) which impart a bimodal grain-size distribution to the graded muds. The texturally incompatible grain populations of the muds (median size between 4 and 8 micrometers) and the coarse silt and sand-sized IRD require the combination of two transport processes that delivered the populations independently and allowed mixing at the depositional site: (i) sediment rafting by icebergs and (ii) the rise of turbid freshwater plumes out of fresh-water generated turbidity currents. Fresh-water generated turbidity currents have built a huge sand and gravel abyssal plain in the Labrador Sea (700 by 120 km underlain by 150 m of coarse-grained sediment on average) which is one of the largest sand accumulations (104 km3) on Earth. The hyperpycnal portion of individual discharge events that generated these currents would have had an estimated volume on the order of 103 km3 (1012 m3) which would have flowed for 10-15 days or less, assuming estimated discharge ranges for subglacial outburst floods of up to 106 m3/s. Sediment lofting from turbidity currents is a process that occurs in density currents

  20. Performance of Denitrifying Bioreactors at Reducing  Agricultural Nitrogen Pollution in a Humid  Subtropical Coastal Plain Climate

    Directory of Open Access Journals (Sweden)

    Timothy Rosen

    2017-02-01

    Full Text Available Denitrifying bioreactors are an agricultural best management practice developed in the  midwestern United States to treat agricultural drainage water enriched with nitrate‐nitrogen (NO3N. The practice is spreading rapidly to agricultural regions with poor water quality due to nutrient  enrichment. This makes it imperative to track bioreactor NO3‐N reduction efficiency as this practice  gets deployed to new regions. This study evaluated the application and performance of denitrifying  bioreactors in the humid subtropical coastal plain environment of the Chesapeake Bay catchment to  provide data about regionally specific NO3‐N reduction efficiencies. NO3‐N samples were taken  before  and  after  treatment  at  three  denitrifying  bioreactors,  in  addition  to  other  nutrients  (orthophosphate‐phosphorus,  PO4‐P;  ammonium‐nitrogen,  NH4‐N;  total  nitrogen,  TN;  total  phosphorus,  TP  and  water  quality  parameters  (dissolved  oxygen,  DO;  oxidation  reduction  potential,  ORP;  pH;  specific  conductance,  SPC.  Total  removal  ranged  drastically  between  bioreactors from 10 to 133 kg N, with removal efficiencies of 9.0% to 62% and N removal rates of  0.21 to 5.36 g N removed per m3 of bioreactor per day. As the first bioreactor study in the humid  subtropical coastal plain, this data provides positive proof of concept that denitrifying bioreactor is  another tool for reducing N loads in agricultural tile drainage in this region.

  1. Experimental study of humidity distribution inside electronic enclosure and effect of internal heating

    DEFF Research Database (Denmark)

    Conseil, Helene; Jellesen, Morten Stendahl; Ambat, Rajan

    2016-01-01

    on the humidity and temperature profile inside typical electronic enclosures. Defined parameters include external temperature and humidity conditions, temperature and time of the internal heat cycle, thermal mass, and ports/openings size. The effect of the internal humidity on electronic reliability has been......Corrosion reliability of electronic products is a key factor for electronics industry, and today there is a large demand for performance reliability in a wide range of temperature and humidity during day and night time periods. Corrosion failures are still a challenge due to the combined effects...... of temperature, humidity and corrosion accelerating species in the atmosphere. Moreover the surface region of printed circuit board assemblies is often contaminated by various aggressive chemical species.This study describes the overall effect of the exposure to severe climate conditions and internal heat cycles...

  2. Climate fluctuations during the Holocene in NW Iberia: High and low latitude linkages

    Science.gov (United States)

    Pena, L. D.; Francés, G.; Diz, P.; Esparza, M.; Grimalt, J. O.; Nombela, M. A.; Alejo, I.

    2010-07-01

    High resolution benthic foraminiferal stable isotopes (δ 18O, δ 13C) and molecular biomarkers in the sediments are used here to infer rapid climatic changes for the last 8200 years in the Ría de Muros (NW Iberian Margin). Benthic foraminiferal δ 18O and δ 13C potentially register migrations in the position of the hydrographic front formed between two different intermediate water masses: Eastern North Atlantic Central Water of subpolar origin (ENACW sp) and subtropical origin (ENACW st). The molecular biomarkers in the sediment show a strong coupling between continental organic matter inputs and negative δ 13C values in benthic foraminifera. The rapid centennial and millennial events registered in these records have been compared with two well known North Atlantic Holocene records from the subtropical Atlantic sea surface temperatures (SST) anomalies off Cape Blanc, NW Africa and the subpolar Atlantic (Hematite Stained Grains percentage, subpolar North Atlantic). Comparison supports a strong link between high- and low-latitude climatic perturbations at centennial-millennial time scales during the Holocene. Spectral analyses also points to a pole-to-equator propagation of the so-called 1500 yr cycles. Our results demonstrate that during the Holocene, the NW Iberian Margin has undergone a series of rapid events which are likely triggered at high latitudes in the North Atlantic and are rapidly propagated towards lower latitudes. Conceivably, the propagation of these rapid climatic changes involves a shift in atmospheric and oceanic circulatory systems.

  3. A physically based analytical spatial air temperature and humidity model

    Science.gov (United States)

    Yang, Yang; Endreny, Theodore A.; Nowak, David J.

    2013-09-01

    Spatial variation of urban surface air temperature and humidity influences human thermal comfort, the settling rate of atmospheric pollutants, and plant physiology and growth. Given the lack of observations, we developed a Physically based Analytical Spatial Air Temperature and Humidity (PASATH) model. The PASATH model calculates spatial solar radiation and heat storage based on semiempirical functions and generates spatially distributed estimates based on inputs of topography, land cover, and the weather data measured at a reference site. The model assumes that for all grids under the same mesoscale climate, grid air temperature and humidity are modified by local variation in absorbed solar radiation and the partitioning of sensible and latent heat. The model uses a reference grid site for time series meteorological data and the air temperature and humidity of any other grid can be obtained by solving the heat flux network equations. PASATH was coupled with the USDA iTree-Hydro water balance model to obtain evapotranspiration terms and run from 20 to 29 August 2010 at a 360 m by 360 m grid scale and hourly time step across a 285 km2 watershed including the urban area of Syracuse, NY. PASATH predictions were tested at nine urban weather stations representing variability in urban topography and land cover. The PASATH model predictive efficiency R2 ranged from 0.81 to 0.99 for air temperature and 0.77 to 0.97 for dew point temperature. PASATH is expected to have broad applications on environmental and ecological models.

  4. Simulation of electronic circuit sensitivity towards humidity using electrochemical data on water layer

    DEFF Research Database (Denmark)

    Joshy, Salil; Verdingovas, Vadimas; Jellesen, Morten Stendahl

    2015-01-01

    Climatic conditions like temperature and humidity have direct influence on the operation of electronic circuits. The effects of temperature on the operation of electronic circuits have been widely investigated, while the effect of humidity and solder flux residues are not well understood including...... the effect on circuit and PCBA (printed circuit board assembly) layout design. This paper elucidates a methodology for analyzing the sensitivity of an electronic circuit based on parasitic circuit analysis using data on electrical property of the water layer formed under humid as well as contaminated...

  5. Holocene climate change in North Africa and the end of the African humid period - results of new high-resolution transient simulations with the MPI-ESM 1.3

    Science.gov (United States)

    Dallmeyer, Anne; Claussen, Martin; Lorenz, Stephan

    2017-04-01

    The Max-Planck-Institute for Meteorology has recently undertaken high-resolution transient Holocene simulations using the fully-coupled Earth System Model MPI-ESM 1.3. The simulations cover the last 8000 years and are forced not only by reconstructed Holocene orbital variations and atmospheric greenhouse gas concentrations, but also by recent compilations of Holocene volcanic aerosol distributions, variations in spectral solar irradiance, stratospheric ozone and land-use change. The simulations reveal the ubiquitous "Holocene conundrum": simulated global mean temperatures increase during the mid-Holocene and stay constant during the late Holocene. Simulated mid-Holocene near-surface temperatures are too cold in large parts of the world. Simulated precipitation, however, agrees much better with reconstruction than temperatures do. Likewise simulated global biome pattern fit reconstructions nicely, except for North Western America. First results of these simulations are presented with the main focus on the North African monsoon region. The amplitude of the mid-Holocene African Humid Period (AHP) is well captured in terms of precipitation and vegetation cover, so is the south-ward transgression of the termination of the AHP seen in reconstructions. The Holocene weakening and southward retreat of the North African monsoon as well as changes in the monsoon dynamic including shifts in the seasonal cycle and their relation to the locally varying termination of the AHP are discussed in detail. Members of the Hamburg Holocene Team: Jürgen Bader (1), Sebastian Bathiany (2), Victor Brovkin (1), Martin Claussen (1,3), Traute Crüger (1), Roberta D'agostino (1), Anne Dallmeyer (1), Sabine Egerer (1), Vivienne Groner (1), Matthias Heinze (1), Tatiana Ilyina (1), Johann Jungclaus (1), Thomas Kleinen (1), Alexander Lemburg (1), Stephan Lorenz (1), Thomas Raddatz (1), Hauke Schmidt (1), Gerhard Schmiedl (3), Bjorn Stevens (1), Claudia Timmreck (1), Matthew Toohey (4) (1) Max

  6. Observational evidence for aerosols increasing upper tropospheric humidity

    Directory of Open Access Journals (Sweden)

    L. Riuttanen

    2016-11-01

    Full Text Available Aerosol–cloud interactions are the largest source of uncertainty in the radiative forcing of the global climate. A phenomenon not included in the estimates of the total net forcing is the potential increase in upper tropospheric humidity (UTH by anthropogenic aerosols via changes in the microphysics of deep convection. Using remote sensing data over the ocean east of China in summer, we show that increased aerosol loads are associated with an UTH increase of 2.2 ± 1.5 in units of relative humidity. We show that humidification of aerosols or other meteorological covariation is very unlikely to be the cause of this result, indicating relevance for the global climate. In tropical moist air such an UTH increase leads to a regional radiative effect of 0.5 ± 0.4 W m−2. We conclude that the effect of aerosols on UTH should be included in future studies of anthropogenic climate change and climate sensitivity.

  7. The anthropogenic influence on heat and humidity in the US Midwest

    Science.gov (United States)

    Inda Diaz, H. A.; O'Brien, T. A.; Stone, D. A.

    2016-12-01

    Heatwaves, and extreme temperatures in general, have a wide range of negative impacts on society, and particularly on human health. In addition to temperature, humidity plays a key role in regulating human body temperature, with higher humidities tending to reduce the effectiveness of perspiration. There is recent theoretical and observational evidence that co-occurring extreme heat and humidity can potentially have a much more dramatic impact on human health than either extreme in isolation. There is an abundance of observational evidence indicating that anthropogenic increases in greenhouse gas (GHG) forcing have contributed to an increase in the intensity and frequency of temperature extremes on a global scale. However, aside from purely thermodynamically-driven increases in near-surface humidity, there is a paucity of similar evidence for anthropogenic impacts on humidity. Thermodynamic scaling would suggest that air masses originating from the ocean would be associated with higher specific humidity in a warmer world, and transpiration from irrigated crops could further increase humidity in warm air masses. In order to explore the role of anthropogenic GHG forcing on the co-occurrence of temperature and humidity extremes in the Midwestern United States (US), we evaluate a large ensemble of global climate model simulations with and without anthropogenic GHG forcing. In particular, we examine differences between the probability distributions of near-surface temperature, humidity, wet-bulb temperature, and the joint distribution of temperature and humidity in this ensemble. Finally, we explore augmenting this experimental framework with additional simulations to explore the role of anthropogenic changes in the land surface, and in particular irrigated crops, on co-occurring extreme heat and humidity.

  8. The impact of relative humidity and atmospheric pressure on mortality in Guangzhou, China.

    Science.gov (United States)

    Ou, Chun Quan; Yang, Jun; Ou, Qiao Qun; Liu, Hua Zhang; Lin, Guo Zhen; Chen, Ping Yan; Qian, Jun; Guo, Yu Ming

    2014-12-01

    Although many studies have examined the effects of ambient temperatures on mortality, little evidence is on health impacts of atmospheric pressure and relative humidity. This study aimed to assess the impacts of atmospheric pressure and relative humidity on mortality in Guangzhou, China. This study included 213,737 registered deaths during 2003-2011 in Guangzhou, China. A quasi-Poisson regression with a distributed lag non-linear model was used to assess the effects of atmospheric pressure/relative humidity. We found significant effect of low atmospheric pressure/relative humidity on mortality. There was a 1.79% (95% confidence interval: 0.38%-3.22%) increase in non-accidental mortality and a 2.27% (0.07%-4.51%) increase in cardiovascular mortality comparing the 5th and 25th percentile of atmospheric pressure. A 3.97% (0.67%-7.39%) increase in cardiovascular mortality was also observed comparing the 5th and 25th percentile of relative humidity. Women were more vulnerable to decrease in atmospheric pressure and relative humidity than men. Age and education attainment were also potential effect modifiers. Furthermore, low atmospheric pressure and relative humidity increased temperature-related mortality. Both low atmospheric pressure and relative humidity are important risk factors of mortality. Our findings would be helpful to develop health risk assessment and climate policy interventions that would better protect vulnerable subgroups of the population. Copyright © 2014 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

  9. VAB Temperature and Humidity Study

    Science.gov (United States)

    Lane, John E.; Youngquist, Robert C.; Muktarian, Edward; Nurge, Mark A.

    2014-01-01

    In 2012, 17 data loggers were placed in the VAB to measure temperature and humidity at 10-minute intervals over a one-year period. In 2013, the data loggers were replaced with an upgraded model and slight adjustments to their locations were made to reduce direct solar heating effects. The data acquired by the data loggers was compared to temperature data provided by three wind towers located around the building. It was found that the VAB acts as a large thermal filter, delaying and reducing the thermal oscillations occurring outside of the building. This filtering is typically more pronounced at higher locations in the building, probably because these locations have less thermal connection with the outside. We surmise that the lower elevations respond more to outside temperature variations because of air flow through the doors. Temperatures inside the VAB rarely exceed outdoor temperatures, only doing so when measurements are made directly on a surface with connection to the outside (such as a door or wall) or when solar radiation falls directly on the sensor. A thermal model is presented to yield approximate filter response times for various locations in the building. Appendix A contains historical thermal and humidity data from 1994 to 2009.

  10. Characterization of spacecraft humidity condensate

    Science.gov (United States)

    Muckle, Susan; Schultz, John R.; Sauer, Richard L.

    1994-01-01

    When construction of Space Station Freedom reaches the Permanent Manned Capability (PMC) stage, the Water Recovery and Management Subsystem will be fully operational such that (distilled) urine, spent hygiene water, and humidity condensate will be reclaimed to provide water of potable quality. The reclamation technologies currently baselined to process these waste waters include adsorption, ion exchange, catalytic oxidation, and disinfection. To ensure that the baseline technologies will be able to effectively remove those compounds presenting a health risk to the crew, the National Research Council has recommended that additional information be gathered on specific contaminants in waste waters representative of those to be encountered on the Space Station. With the application of new analytical methods and the analysis of waste water samples more representative of the Space Station environment, advances in the identification of the specific contaminants continue to be made. Efforts by the Water and Food Analytical Laboratory at JSC were successful in enlarging the database of contaminants in humidity condensate. These efforts have not only included the chemical characterization of condensate generated during ground-based studies, but most significantly the characterization of cabin and Spacelab condensate generated during Shuttle missions. The analytical results presented in this paper will be used to show how the composition of condensate varies amongst enclosed environments and thus the importance of collecting condensate from an environment close to that of the proposed Space Station. Although advances were made in the characterization of space condensate, complete characterization, particularly of the organics, requires further development of analytical methods.

  11. Persistent shift of Calanus spp. in the south-western Norwegian Sea since 2003, linked to ocean climate

    DEFF Research Database (Denmark)

    Kristiansen, Inga; Gaard, Eilif; Hátún, Hjalmar

    2016-01-01

    The southwestern Norwegian Sea is characterized by an inflow of warm and saline Atlantic water from the southwest and cold and less saline East IcelandicWater (EIW), of Arctic origin, from the northwest. These two water masses meet and form the Iceland-Faroe Front (IFF). In this region, the copep...... on the ecosystem and pelagic fish in this subpolar Atlantic region under expected climate change...

  12. Comparison of land surface humidity between observations and CMIP5 models

    Science.gov (United States)

    Dunn, Robert J. H.; Willett, Kate M.; Ciavarella, Andrew; Stott, Peter A.

    2017-08-01

    We compare the latest observational land surface humidity dataset, HadISDH, with the latest generation of climate models extracted from the CMIP5 archive and the ERA-Interim reanalysis over the period 1973 to present. The globally averaged behaviour of HadISDH and ERA-Interim are very similar in both humidity measures and air temperature, on decadal and interannual timescales. The global average relative humidity shows a gradual increase from 1973 to 2000, followed by a steep decline in recent years. The observed specific humidity shows a steady increase in the global average during the early period but in the later period it remains approximately constant. None of the CMIP5 models or experiments capture the observed behaviour of the relative or specific humidity over the entire study period. When using an atmosphere-only model, driven by observed sea surface temperatures and radiative forcing changes, the behaviour of regional average temperature and specific humidity are better captured, but there is little improvement in the relative humidity. Comparing the observed climatologies with those from historical model runs shows that the models are generally cooler everywhere, are drier and less saturated in the tropics and extra-tropics, and have comparable moisture levels but are more saturated in the high latitudes. The spatial pattern of linear trends is relatively similar between the models and HadISDH for temperature and specific humidity, but there are large differences for relative humidity, with less moistening shown in the models over the tropics and very little at high latitudes. The observed drying in mid-latitudes is present at a much lower magnitude in the CMIP5 models. Relationships between temperature and humidity anomalies (T-q and T-rh) show good agreement for specific humidity between models and observations, and between the models themselves, but much poorer for relative humidity. The T-q correlation from the models is more steeply positive than

  13. Shallow Land Burial Technology - Humid

    International Nuclear Information System (INIS)

    Davis, E.C.; Spalding, B.P.; Lee, S.Y.

    1983-01-01

    The Shallow Land Burial Technology - Humid Project is being conducted for the Department of Energy Low-Level Waste Management Program with the objective of identifying and demonstrating improved technology for disposing of low-level solid waste in humid environments. Two improved disposal techniques are currently being evaluated using nine demonstration trenches at the Engineered Test Facility (ETF). The first is use of a cement-bentonite grout applied as a waste backfill material prior to trench closure and covering. The second is complete hydrologic isolation of waste by emplacement in a trench that is lined on all four sides, top and bottom using synthetic impermeable lining material. An economic analysis of the trench grouting and lining demonstration favored the trench lining operation ($1055/demonstration trench) over trench grouting ($1585/demonstration trench), with the cost differential becoming even greater (as much as a factor of 6 in favor of lining for typical ORNL trenches) as trench dimensions increase and trench volumes exceed those of the demonstration trenches. In addition to the evaluation of trench grouting and lining, major effort has centered on characterization of the ETF site. Though only a part of the overall study, characterization is an extremely important component of the site selection process; it is during these activities that potential problems, which may obviate the site from further consideration, are found. Characterization of the ETF has included studies of regional and site-specific geology, the physical and chemical properties of the soils in which the demonstration trenches are located, and hydrology of the small watershed of which the ETF is a part. 12 references, 6 figures, 2 tables

  14. EFICIENCIA ENERGÉTICA POR LA UTILIZACIÓN DE COMPONENTES DE CONDUCCIÓN DE LUZ NATURAL EN CLIMA CÁLIDO-HÚMEDO | ENERGETIC EFFICIENCY DERIVED FROM THE USE OF CONDUCTION COMPONENTS OF DAYLIGHT IN WARM-HUMID CLIMATE

    Directory of Open Access Journals (Sweden)

    Rosalinda González Gómez

    2015-11-01

    Full Text Available The electric energy saving was estimated by the utilization of Conduction Components of Daylight (CCD in warm-humid climate. For this, the luminic performance of the component was determined, considering values of horizontal exterior lighting and interior lighting obtained by monitoring under real sky conditions in scale models, and the comparison with incandescent bulbs and Compact Fluorescent Lamps (CFL. The utilization of the natural light through CCLN allows to obtain a saving in the expense for energy, with respect to the use of Incandescent Bulb and/or Compact Fluorescent Lamp (artificial lighting. In this sense, their use would correspond to 219 KWh and to 54.75 KWh, respectively, if they are used for an average of 10 daily hours, during a period of one year. It was estimated that a possible reduction could be achieved in the electricity consumption, maintaining the comfort and quality of life of the users in buildings (high luminic performance without use of energy from commercial supplier, contributing this way to the "energy efficiency" in them.

  15. Passive Wireless SAW Humidity Sensors, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal describes the preliminary development of passive wireless surface acoustic wave (SAW) based humidity sensors for NASA application to distributed...

  16. Model, Proxy and Isotopic Perspectives on the East African Humid Period

    Science.gov (United States)

    Tierney, Jessica E.; Lewis, Sophie C.; Cook, Benjamin I.; LeGrande, Allegra N.; Schmidt, Gavin A.

    2011-01-01

    Both North and East Africa experienced more humid conditions during the early and mid-Holocene epoch (11,000-5000yr BP; 11-5 ka) relative to today. The North African Humid Period has been a major focus of paleoclimatic study, and represents a response of the hydrological cycle to the increase in boreal summer insolation and associated ocean, atmosphere and land surface feedbacks. Meanwhile, the mechanisms that caused the coeval East African Humid Period are poorly understood. Here, we use results from isotopeenabled coupled climate modeling experiments to investigate the cause of the East African Humid Period. The modeling results are interpreted alongside proxy records of both water balance and the isotopic composition of rainfall. Our simulations show that the orbitally-induced increase in dry season precipitation and the subsequent reduction in precipitation seasonality can explain the East African Humid Period, and this scenario agrees well with regional lake level and pollen paleoclimate data. Changes in zonal moisture flux from both the Atlantic and Indian Ocean account for the simulated increase in precipitation from June through November. Isotopic paleoclimate data and simulated changes in moisture source demonstrate that the western East African Rift Valley in particular experienced more humid conditions due to the influx of Atlantic moisture and enhanced convergence along the Congo Air Boundary. Our study demonstrates that zonal changes in moisture advection are an important determinant of climate variability in the East African region.

  17. Identifying Changes in the Probability of High Temperature, High Humidity Heat Wave Events

    Science.gov (United States)

    Ballard, T.; Diffenbaugh, N. S.

    2016-12-01

    Understanding how heat waves will respond to climate change is critical for adequate planning and adaptation. While temperature is the primary determinant of heat wave severity, humidity has been shown to play a key role in heat wave intensity with direct links to human health and safety. Here we investigate the individual contributions of temperature and specific humidity to extreme heat wave conditions in recent decades. Using global NCEP-DOE Reanalysis II daily data, we identify regional variability in the joint probability distribution of humidity and temperature. We also identify a statistically significant positive trend in humidity over the eastern U.S. during heat wave events, leading to an increased probability of high humidity, high temperature events. The extent to which we can expect this trend to continue under climate change is complicated due to variability between CMIP5 models, in particular among projections of humidity. However, our results support the notion that heat wave dynamics are characterized by more than high temperatures alone, and understanding and quantifying the various components of the heat wave system is crucial for forecasting future impacts.

  18. Mask humidity during CPAP: influence of ambient temperature, heated humidification and heated tubing.

    Science.gov (United States)

    Nilius, Georg; Domanski, Ulrike; Schroeder, Maik; Woehrle, Holger; Graml, Andrea; Franke, Karl-Josef

    2018-01-01

    Mucosal drying during continuous positive airway pressure (CPAP) therapy is problematic for many patients. This study assessed the influence of ambient relative humidity (rH) and air temperature (T) in winter and summer on mask humidity during CPAP, with and without mask leak, and with or without heated humidification ± heated tubing. CPAP (8 and 12 cmH 2 O) without humidification (no humidity [nH]), with heated humidification controlled by ambient temperature and humidity (heated humidity [HH]) and HH plus heated tubing climate line (CL), with and without leakage, were compared in 18 subjects with OSA during summer and winter. The absolute humidity (aH) and the T inside the mask during CPAP were significantly lower in winter versus summer under all applied conditions. Overall, absolute humidity differences between summer and winter were statistically significant in both HH and CL vs. nH ( p humidification or with standard HH. Clinically-relevant reductions in aH were documented during CPAP given under winter conditions. The addition of heated humidification, using a heated tube to avoid condensation is recommended to increase aH, which could be useful in CPAP users complaining of nose and throat symptoms.

  19. Graphene based humidity-insensitive films

    KAUST Repository

    Tai, Yanlong; Lubineau, Gilles

    2017-01-01

    A humidity nonsensitive material based on reduced-graphene oxide (r-GO) and methods of making the same are provided, in an embodiment, the materia! has a resistance/humidity variation of about -15% to 15% based on different sintering time

  20. Temperature and Humidity Control in Livestock Stables

    DEFF Research Database (Denmark)

    Hansen, Michael; Andersen, Palle; Nielsen, Kirsten M.

    2010-01-01

    The paper describes temperature and humidity control of a livestock stable. It is important to have a correct air flow pattern in the livestock stable in order to achieve proper temperature and humidity control as well as to avoid draught. In the investigated livestock stable the air flow...

  1. Direct versus indirect effects of tropospheric humidity changes on the hydrologic cycle

    International Nuclear Information System (INIS)

    Sherwood, S C

    2010-01-01

    Abundant evidence indicates that tropospheric specific humidity increases in a warmer atmosphere, at rates roughly comparable to those at constant relative humidity. While the implications for the planetary energy budget and global warming are well recognized, it is the net atmospheric cooling (or surface heating) that controls the hydrologic cycle. Relative humidity influences this directly through gas-phase radiative transfer, and indirectly by affecting cloud cover (and its radiative effects) and convective heating. Simple calculations show that the two indirect impacts are larger than the direct impact by roughly one and two orders of magnitude respectively. Global or regional relative humidity changes could therefore have significant indirect impacts on energy and water cycles, especially by altering deep convection, even if they are too small to significantly affect global temperature. Studies of climate change should place greater emphasis on these indirect links, which may not be adequately represented in models.

  2. A Humidity-Dependent Lifetime Derating Factor for DC Film Capacitors

    DEFF Research Database (Denmark)

    Wang, Huai; Reigosa, Paula Diaz; Blaabjerg, Frede

    2015-01-01

    accelerated testing of film capacitors under different humidity conditions, enabling a more justified lifetime prediction of film capacitors for DC-link applications under specific climatic environments. The analysis of the testing results and the detailed discussion on the derating factor with different......Film capacitors are widely assumed to have superior reliability performance than Aluminum electrolytic capacitors in DC-link design of power electronic converters. However, the assumption needs to be critically judged especially for applications under high humidity environments. This paper proposes...... a humidity-dependent lifetime derating factor for a type of plastic-boxed metallized DC film capacitors. It overcomes the limitation that the humidity impact is not considered in the state-of-the-art DC film capacitor lifetime models. The lifetime derating factor is obtained based on a total of 8,700 hours...

  3. Influence of ambient humidity on the current delivered by air-vented ionization chambers revisited

    International Nuclear Information System (INIS)

    Poirier, Aurelie; Douysset, Guilhem

    2006-01-01

    The influence of ambient humidity on the current delivered by a vented ionization chamber has been re-investigated. A Nucletron 077.091 well-type chamber together with a 192 Ir HDR brachytherapy source was enclosed in a climatic test chamber and the current was recorded for various humidity values. Great care has been taken for the design of the experimental setup in order to obtain reliable measurements of currents and humidity values inside the chamber active volume. A ±0.35% linear variation of the measured currents has been observed over a common range of humidities. This result is larger than the expected variation. No formal explanation of such a discrepancy has been found yet, however the present results could lead to a set of recommendations

  4. Influence of ambient humidity on the current delivered by air-vented ionization chambers revisited

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, Aurelie; Douysset, Guilhem [Laboratoire National Henri Becquerel-LNE, CEA Saclay 91191 Gif-sur-Yvette (France)

    2006-10-07

    The influence of ambient humidity on the current delivered by a vented ionization chamber has been re-investigated. A Nucletron 077.091 well-type chamber together with a {sup 192}Ir HDR brachytherapy source was enclosed in a climatic test chamber and the current was recorded for various humidity values. Great care has been taken for the design of the experimental setup in order to obtain reliable measurements of currents and humidity values inside the chamber active volume. A {+-}0.35% linear variation of the measured currents has been observed over a common range of humidities. This result is larger than the expected variation. No formal explanation of such a discrepancy has been found yet, however the present results could lead to a set of recommendations.

  5. Humidity detection using chitosan film based sensor

    Science.gov (United States)

    Nasution, T. I.; Nainggolan, I.; Dalimunthe, D.; Balyan, M.; Cuana, R.; Khanifah, S.

    2018-02-01

    A humidity sensor made of the natural polymer chitosan has been successfully fabricated in the film form by a solution casting method. Humidity testing was performed by placing a chitosan film sensor in a cooling machine room, model KT-2000 Ahu. The testing results showed that the output voltage values of chitosan film sensor increased with the increase in humidity percentage. For the increase in humidity percentage from 30 to 90% showed that the output voltage of chitosan film sensor increased from 32.19 to 138.75 mV. It was also found that the sensor evidenced good repeatability and stability during the testing. Therefore, chitosan has a great potential to be used as new sensing material for the humidity detection of which was cheaper and environmentally friendly.

  6. Graphene based humidity-insensitive films

    KAUST Repository

    Tai, Yanlong

    2017-09-08

    A humidity nonsensitive material based on reduced-graphene oxide (r-GO) and methods of making the same are provided, in an embodiment, the materia! has a resistance/humidity variation of about -15% to 15% based on different sintering time or temperature. In an aspect, the resistance variation to humidity can be close to zero or -0.5% to 0.5%, showing a humidity non sensitivity property. In an embodiment, a humidity nonsensitive material based on the r-GO and carbon nanotube (CNT) composites is provided, wherein the ratio of CNT to r-GO is adjusted. The ratio can be adjusted based on the combined contribution of carbon nanotube (positive resistance variation) and reduced- graphene oxide (negative resistance variation) behaviors.

  7. Modelling soil moisture under different land covers in a sub-humid ...

    Indian Academy of Sciences (India)

    in the sub-humid climate within the Western Ghats, Karnataka, India. ... carried out with respect to the water-holding capacity of the soils with the aim of explaining ... changes have taken place in the land-use/cover of ... about 20–25 km inland.

  8. The role of absorbent building materials in moderating changes of relative humidity

    DEFF Research Database (Denmark)

    Padfield, Tim

    The problem studied in this work is, how porous, absorbent materials surroundning or placed in a room influence the relative humidity of the room. This is of interest in designing precautions and machinery to monitor the indoor climate in museums and dwelling rooms. - A novel technique for the in...

  9. Endotracheal temperature and humidity measurements in laryngectomized patients: intra- and inter-patient variability

    NARCIS (Netherlands)

    Scheenstra, R.J.; Muller, S.H.; Vincent, A.; Sinaasappel, M.; Zuur, J.K.; Hilgers, F.J.M.

    2009-01-01

    This study assesses intra- and inter-patient variability in endotracheal climate (temperature and humidity) and effects of heat and moister exchangers (HME) in 16 laryngectomized individuals, measured repeatedly (N = 47). Inhalation Breath Length (IBL) was 1.35 s without HME and 1.05 s with HME (P <

  10. Endotracheal temperature and humidity measurements in laryngectomized patients: intra- and inter-patient variability

    NARCIS (Netherlands)

    Scheenstra, R. J.; Muller, S. H.; Vincent, A.; Sinaasappel, M.; Zuur, J. K.; Hilgers, Frans J. M.

    2009-01-01

    This study assesses intra- and inter-patient variability in endotracheal climate (temperature and humidity) and effects of heat and moister exchangers (HME) in 16 laryngectomized individuals, measured repeatedly (N = 47). Inhalation Breath Length (IBL) was 1.35 s without HME and 1.05 s with HME (P

  11. Analysis of humidity effects on growth and production of glasshouse fruit vegetables

    NARCIS (Netherlands)

    Bakker, J.C.

    1991-01-01

    Air humidity is a climate factor that can modify final yield and quality of crops through its impact on processes with a short as well as with a long response time. This thesis primarily deals with the long term responses of growth and production of glasshouse cucumber, tomato, sweet pepper and

  12. Humidity control device in a reactor container

    International Nuclear Information System (INIS)

    Aizawa, Motohiro; Igarashi, Hiroo; Osumi, Katsumi; Kimura, Takashi.

    1986-01-01

    Purpose: To provide a device capable of maintaining the inside of a container under high humidity circumstantial conditions causing less atmospheric corrosions, in order to prevent injuries due to atmospheric corrosions to smaller diameter stainless steel pipeways in the reactor container. Constitution: Stress corrosion cracks (SCC) to the smaller diameter stainless steel pipeways are caused dependent on the relative humidity and it is effective as the countermeasure against SCC to maintain the relative humidity at a low level less than 30 % or high level greater than 60 %. Based on the above findings, a humidity control device is disposed so as to maintain the relative humidity for the atmosphere within a reactor core on a higher humidity region. The device is adapted such that recycling gas in the dry-well coolant circuit is passed through an orifice to atomize the water introduced from feedwater pipe and introduce into a reactor core or such that the recycling gases in the dry-well cooling circuit are bubbled into water to remove chlorine gas in the reactor container gas thereby increasing the humidity in the reactor container. (Kamimura, M.)

  13. The Influence of Edaphic and Orographic Factors on Algal Diversity in Biological Soil Crusts on Bare Spots in the Polar and Subpolar Urals

    Science.gov (United States)

    Patova, E. N.; Novakovskaya, I. V.; Deneva, S. V.

    2018-03-01

    The influence of edaphic and orographic factors on the formation of algal diversity in biological soil crusts was studied in mountain tundras of the Polar and Subpolar Urals. Bare spots developed in the soils on different parent materials and overgrown to different extents were investigated. Overall, 221 algal species from six divisions were identified. Among them, eighty-eight taxa were new for the region studied. The Stigonema minutum, S. ocellatum, Nostoc commune, Gloeocapsopsis magma, Scytonema hofmannii, Leptolyngbya foveolarum, Pseudococcomyxa simplex, Sporotetras polydermatica species and species of the Cylindrocystis, Elliptochloris, Fischerella, Leptosira, Leptolyngbya, Myrmecia, Mesotaenium, Phormidium, Schizothrix genera were permanent components of biological soil crusts. The basis of the algal cenoses in soil crusts was composed of cosmopolitan cyanoprokaryotes, multicellular green algae with thickened covers and abundant mucus. The share of nitrogen fixers was high. The physicochemical properties of primary soils forming under the crusts of spots are described. The more important factors affecting the species composition of algae in the crusts are the elevation gradient, temperature, soil moisture, and the contents of Ca, Mg, mobile phosphorus, and total nitrogen.

  14. Mid-Holocene Strengthening of the Bering Strait Inflow to the Arctic and its Linkage With the North Atlantic Subpolar Gyre Circulation

    Science.gov (United States)

    Yamamoto, M.; Nam, S. I.; Polyak, L.; Kobayashi, D.; Suzuki, K.; Irino, T.; Shimada, K.

    2017-12-01

    The Bering Strait inflow (BSI) is an important element of the Arctic Ocean circulation system. We report records of the chlorite/illite ratios in three sediment cores from the northern Chukchi Sea providing insights into the long-term dynamics of the BSI during the Holocene. The BSI approximation by the chlorite/illite record, despite a considerable geographic variability, consistently shows intensified flow from the Bering Sea to the Arctic during the middle Holocene, which is attributed primarily to the effect of higher atmospheric pressure over the Aleutian Basin. The intensified BSI was associated with decrease in sea-ice concentrations and increase in marine production, as indicated by biomarker concentrations, suggesting a major influence of the BSI on sea-ice and biological conditions in the Chukchi Sea. Multi-century to millennial fluctuations, presumably controlled by solar activity, were also identified. This middle Holocene strengthening of the BSI was coeval with intense subpolar gyre circulation in the North Atlantic. We propose that the BSI is linked with the North Atlantic circulation via an atmospheric teleconnection between the Aleutian and Icelandic Lows.

  15. Clinker mineral hydration at reduced relative humidities

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Hansen, Per Freiesleben; Lachowski, Eric E.

    1999-01-01

    and experimental data are presented showing that C(3)A can hydrate at lower humidities than either C3S or C2S. It is suggested that the initiation of hydration during exposure to water vapour is nucleation controlled. When C(3)A hydrates at low humidity, the characteristic hydration product is C(3)AH(6......Vapour phase hydration of purl cement clinker minerals at reduced relative humidities is described. This is relevant to modern high performance concrete that may self-desiccate during hydration and is also relevant to the quality of the cement during storage. Both the oretical considerations...

  16. Laboratory setup for temperature and humidity measurements

    CERN Document Server

    Eimre, Kristjan

    2015-01-01

    In active particle detectors, the temperature and humidity conditions must be under constant monitoring and control, as even small deviations from the norm cause changes to detector characteristics and result in a loss of precision. To monitor the temperature and humidity, different kinds of sensors are used, which must be calibrated beforehand to ensure their accuracy. To calibrate the large number of sensors that are needed for the particle detectors and other laboratory work, a calibration system is needed. The purpose of the current work was to develop a laboratory setup for temperature and humidity sensor measurements and calibration.

  17. Dinocysts as tracers of sea-surface conditions and sea-ice cover in polar and subpolar environments

    International Nuclear Information System (INIS)

    De Vernal, Anne; Rochon, Andre

    2011-01-01

    Dinoflagellates are unicellular protists that produce a cyst (dinocyst) as part of their life cycle. The cyst wall of many species is composed of highly resistant organic matter. Dinocysts are thus routinely recovered in marine sediments and occur in high number along the continental margins of the world oceans notably in high latitude environments. They are widely used as proxy indicators of marine conditions and provide valuable information on the natural variability of climate, which in turn helps understanding and assessing the potential threat posed by the actual global warming. Here we present a brief outline of their biology, ecology and distribution in Arctic and subarctic areas. We also provide a few examples of paleoenvironmental reconstructions and briefly discuss on the significance of these results.

  18. Dinocysts as tracers of sea-surface conditions and sea-ice cover in polar and subpolar environments

    Energy Technology Data Exchange (ETDEWEB)

    De Vernal, Anne [GEOTOP, Universite du Quebec a Montreal, PO Box 8888, succursale ' centre ville' Montreal, Qc, H3C 3P8 (Canada); Rochon, Andre, E-mail: devernal.anne@uqam.ca [GEOTOP and Institut des Sciences de la Mer (ISMER), Universite du Quebec a Rimouski, 310, Allee des Ursulines, Rimouski, Qc, G5L 3A1 (Canada)

    2011-05-15

    Dinoflagellates are unicellular protists that produce a cyst (dinocyst) as part of their life cycle. The cyst wall of many species is composed of highly resistant organic matter. Dinocysts are thus routinely recovered in marine sediments and occur in high number along the continental margins of the world oceans notably in high latitude environments. They are widely used as proxy indicators of marine conditions and provide valuable information on the natural variability of climate, which in turn helps understanding and assessing the potential threat posed by the actual global warming. Here we present a brief outline of their biology, ecology and distribution in Arctic and subarctic areas. We also provide a few examples of paleoenvironmental reconstructions and briefly discuss on the significance of these results.

  19. Drought or humidity oscillations? The case of coastal zone of Lebanon

    Science.gov (United States)

    Shaban, Amin; Houhou, Rola

    2015-10-01

    There is discrepancy in classifying Lebanon according to the different climatic zones; however, it is often described as a semi-arid region. Lately, Lebanon has been witnessing climatic oscillations in the meteorological parameters. The impact of these oscillations on water sector has been reflected also on energy-food nexus. Yet, there are a number of studies obtained to identify the climate of Lebanon, and they show contradictory results; especially these studies elaborated different datasets and applied diverse methods which often modeled only on large-scale regions. Therefore, the analysis of climatic data depended on complete and long-term climatic records that can be applied to assess the existing climatic status of Lebanon, as well as to assure whether Lebanon is under drought, humidity or it is oscillating between both. This study utilized considerable datasets, from different sources including the remotely sensed systems (e.g. TRMM). These datasets were interpolated and analyzed statistically according to De Martonne Aridity Index. Aiming to affirm the climatic attribute of Lebanon; however, ten climatic stations were investigated. They are with representative geographic setting and diverse time series in the coastal zone of Lebanon were investigated. Even though, Lebanon is known as a semi-arid region, yet results in this study show that the studied zone does not evidence any drought, since around 70% of the investigated years are characterized by semi-humid to humid climate. This climatic figure is well pronounced since rainfall rate exceeds 900 mm, average temperature rate is about 19 °C, and snow remains for a couple of months annually.

  20. Responses of broiler chickens under hot humid tropical climate as ...

    African Journals Online (AJOL)

    NLP) on the growth, haematology and serum biochemistry parameters of broiler chicks. Two hundred and forty day-old broiler chicks were randomly assigned to four treatments which contained 0, 5, 10 and 15g/Kg diets in a Completely ...

  1. Performance Evaluation of a Hot-Humid Climate Community

    Energy Technology Data Exchange (ETDEWEB)

    Osser, R. [Building Science Corporation, Somerville, MA (United States); Kerrigan, P. [Building Science Corporation, Somerville, MA (United States)

    2012-02-01

    This report describes the Project Home Again community in New Orleans, a new development for high-performance, affordable homes for residents who lost their homes to Hurricane Katrina. Building Science Corporation acted as a consultant for the project, advocating design strategies for durability, flood resistance, occupant comfort, and low energy use while maintaining cost effectiveness.

  2. Humidity Response of Polyaniline Based Sensor

    Directory of Open Access Journals (Sweden)

    Mamta PANDEY

    2010-02-01

    Full Text Available Abstract: This paper presents hitherto unreported humidity sensing capacity of emeraldine salt form of polyaniline. Humidity plays a major role in different processes in industries ranging from food to electronic goods besides human comfort and therefore its monitoring is an essential requirement during various processes. Polyaniline has a wide use for making sensors as it can be easily synthesized and has long stability. Polyaniline is synthesized here by chemical route and is found to sense humidity as it shows variation in electrical resistance with variation in relative humidity. Results are presented here for a range of 15 to 90 RH%. The resistance falls from 5.8 to 0.72 Giga ohms as RH varies from 15 to 65 % and then falls to 13.9 Mega ohms as RH approaches 90 %. The response and recovery times are also measured.

  3. Effect of the temperature and relative humidity in dosemeters used for personnel monitoring

    International Nuclear Information System (INIS)

    Antonio Filho, J.

    1982-12-01

    The systematics of the combined effect of temperature and humidity on photographic dosimeters of the type Agfa-Gevaert, Kodak type II, III and the thermoluminescent dosimeters LiF:Mg,Ti (TLD-100, Harshaw), D-CaSO 4 :Dy-0,4 (Teledyne), e CaSO 4 :Dy+NaCl (IPEN), used in personal monitoring in Brazil was investigated, in the temperature range of 20 0 C to 50 0 C and relative humidity of 65% to 95%, in order to determine the best manner of utilization of these detectors in Brazilian climatic conditions. The dosimeters were studied in different forms of packing-sheet such as aluminezed paper and polyethylene. For the determination of the systematics, the dosimeters were irradiated in three conditions: before, during and after of storage in climatic chambers to a maximum period of 60 days. It was found that the dosimetric filmes and thermoluminescent dosimeter CaSO 4 :Dy+NaCl without protection, presented a high dependence to temperature and humidity, and when protected presented good results. Therefore, the best manner of utilization of these monitors in environments with relative humidity and temperature greater them 75% and 30 0 C respectively, is achieved with the protection of aluminized paper. The LiF:Mg,Ti and D+CaSO 4 :Dy-0,4 dosimeters can be utilized in their original form because they presented low dependence with humidity and temperature in the range studied. (Author) [pt

  4. Humidity measurements in the precast concrete

    International Nuclear Information System (INIS)

    Hurez, M.

    1986-01-01

    The precast concrete industry manufactures requires a good knowledge and control of the humidity factor: during the manufacturing process, in order to regulate the water content of aggregates, or the fresh concrete workability: during the quality control of the product characteristics. The principles of measurements: conductivity, dielectric characteristics and neutron moisture meters are compared for cost, humidity range, accuracy, temperature dependence, interfering elements, density dependence, grain size and shape [fr

  5. Microbial and viral-like rhodopsins present in coastal marine sediments from four polar and subpolar regions

    Energy Technology Data Exchange (ETDEWEB)

    López, José L.; Golemba, Marcelo; Hernández, Edgardo; Lozada, Mariana; Dionisi, Hebe; Jansson, Janet K.; Carroll, Jolynn; Lundgren, Leif; Sjöling, Sara; Mac Cormack, Walter P.; Sobecky, Patricia

    2016-11-03

    Rhodopsins are broadly distributed. In this work, we analyzed 23 metagenomes corresponding to marine sediment samples from four regions that share cold climate conditions (Norway; Sweden; Argentina and Antarctica). In order to investigate the genes evolution of viral rhodopsins, an initial set of 6224 bacterial rhodopsin sequences according to COG5524 were retrieved from the 23 metagenomes. After selection by the presence of transmembrane domains and alignment, 123 viral (51) and non-viral (72) sequences (>50 amino acids) were finally included in further analysis. Viral rhodopsin genes were homologs of Phaeocystis globosa virus and Organic lake Phycodnavirus. Non-viral microbial rhodopsin genes were ascribed to Bacteroidetes, Planctomycetes, Firmicutes, Actinobacteria, Cyanobacteria, Proteobacteria, Deinococcus-Thermus and Cryptophyta and Fungi. A rescreening using Blastp, using as queries the viral sequences previously described, retrieved 30 sequences (>100 amino acids). Phylogeographic analysis revealed a geographical clustering of the sequences affiliated to the viral group. This clustering was not observed for the microbial non-viral sequences. The phylogenetic reconstruction allowed us to propose the existence of a putative ancestor of viral rhodopsin genes related to Actinobacteria and Chloroflexi. This is the first report about the existence of a phylogeographic association of the viral rhodopsin sequences from marine sediments.

  6. Study on the Correlation between Humidity and Material Strains in Separable Micro Humidity Sensor Design

    Directory of Open Access Journals (Sweden)

    Chih-Yuan Chang

    2017-05-01

    Full Text Available Incidents of injuries caused by tiles falling from building exterior walls are frequently reported in Taiwan. Humidity is an influential factor in tile deterioration but it is more difficult to measure the humidity inside a building structure than the humidity in an indoor environment. Therefore, a separable microsensor was developed in this study to measure the humidity of the cement mortar layer with a thickness of 1.5–2 cm inside the external wall of a building. 3D printing technology is used to produce an encapsulation box that can protect the sensor from damage caused by the concrete and cement mortar. The sensor is proven in this study to be capable of measuring temperature and humidity simultaneously and the measurement results are then used to analyze the influence of humidity on external wall tile deterioration.

  7. Evaluation of Temperature and Humidity Profiles of Unified Model and ECMWF Analyses Using GRUAN Radiosonde Observations

    Directory of Open Access Journals (Sweden)

    Young-Chan Noh

    2016-07-01

    Full Text Available Temperature and water vapor profiles from the Korea Meteorological Administration (KMA and the United Kingdom Met Office (UKMO Unified Model (UM data assimilation systems and from reanalysis fields from the European Centre for Medium-Range Weather Forecasts (ECMWF were assessed using collocated radiosonde observations from the Global Climate Observing System (GCOS Reference Upper-Air Network (GRUAN for January–December 2012. The motivation was to examine the overall performance of data assimilation outputs. The difference statistics of the collocated model outputs versus the radiosonde observations indicated a good agreement for the temperature, amongst datasets, while less agreement was found for the relative humidity. A comparison of the UM outputs from the UKMO and KMA revealed that they are similar to each other. The introduction of the new version of UM into the KMA in May 2012 resulted in an improved analysis performance, particularly for the moisture field. On the other hand, ECMWF reanalysis data showed slightly reduced performance for relative humidity compared with the UM, with a significant humid bias in the upper troposphere. ECMWF reanalysis temperature fields showed nearly the same performance as the two UM analyses. The root mean square differences (RMSDs of the relative humidity for the three models were larger for more humid conditions, suggesting that humidity forecasts are less reliable under these conditions.

  8. The Importance of Humidity in the Relationship between Heat and Population Mental Health: Evidence from Australia.

    Science.gov (United States)

    Ding, Ning; Berry, Helen L; Bennett, Charmian M

    2016-01-01

    Despite many studies on the effects of heat on mental health, few studies have examined humidity. In order to investigate the relationship among heat, humidity and mental health, we matched data from the Social, Economic and Environmental Factors (SEEF) project with gridded daily temperature and water vapour pressure data from the Australian Bureau of Meteorology. Logit models were employed to describe the associations among heat (assessed using temperature, °C), humidity (assessed using vapour pressure, hPa) and two measures of mental health, (i) high or very high distress (assessed using K10 scores ≥ 22) and (ii) having been treated for depression or anxiety. We found a one-unit increase in temperature and vapour pressure was associated with an increase in the occurrence of high or very high distress by 0.2% (p humidity rose to the 99th percentile of the sample, the estimated marginal effect of heat was more than doubled (0.5%, p humidity was related to having been treated for depression or anxiety in the last month. Humidity compounds the negative association between hot weather and mental health and thus should be taken into account when reforming the health care system to respond to the challenge of climate change.

  9. Ambient temperature, humidity and hand, foot, and mouth disease: A systematic review and meta-analysis.

    Science.gov (United States)

    Cheng, Qiang; Bai, Lijun; Zhang, Yanwu; Zhang, Heng; Wang, Shusi; Xie, Mingyu; Zhao, Desheng; Su, Hong

    2018-06-01

    The relationship between ambient temperature, humidity and hand, foot, and mouth disease (HFMD) has been highlighted in East and Southeast Asia, which showed multiple different results. Therefore, our goal is to conduct a meta-analysis to further clarify this relationship and to quantify the size of these effects as well as the susceptible populations. PubMed, Web of science, and Cochrane library were searched up to November 22, 2017 for articles analyzing the relationships between ambient temperature, humidity and incidence of HFMD. We assessed sources of heterogeneity by study design (temperature measure and exposed time resolution), population vulnerability (national income level and regional climate) and evaluated pooled effect estimates for the subgroups identified in the heterogeneity analysis. We identified 11 studies with 19 estimates of the relationship between ambient temperature, humidity and incidence of HFMD. It was found that per 1°C increase in the temperature and per 1% increase in the relative humidity were both significantly associated with increased incidence of HFMD (temperature: IRR, 1.05; 95% CI, 1.02-1.08; relative humidity: IRR, 1.01; 95% CI, 1.00-1.02). Subgroup analysis showed that people living in subtropical and middle income areas had a higher risk of incidence of HFMD. Ambient temperature and humidity may increase the incidence of HFMD in Asia-Pacific regions. Further studies are needed to clarify the relationship between ambient temperature, humidity and incidence of HFMD in various settings with distinct climate, socioeconomic, and demographic features. Copyright © 2018. Published by Elsevier B.V.

  10. Medical Meteorology: the Relationship between Meteorological Parameters (Humidity, Rainfall, Wind, and Temperature) and Brucellosis in Zanjan Province

    OpenAIRE

    Yousefali Abedini; Nahideh Mohammadi; Koorosh Kamali; Mohsen Ahadnejad; Mehdi Azari

    2016-01-01

    Background: Brucellosis (Malta fever) is a major contagious zoonotic disease, with economic and public health importance. Methods To assess the effect of meteorological (temperature, rainfall, humidity, and wind) and climate parameters on incidence of brucellosis, brucellosis distribution and meteorological zoning maps of Zanjan Province were prepared using Inverse Distance Weighting (IDW) and Kriging technique in Arc GIS medium. Zoning maps of mean temperature, rainfall, humidity, and win...

  11. The Holocene warm-humid phases in the North China Plain as recorded by multi-proxy records

    Science.gov (United States)

    Cui, Jianxin; Zhou, Shangzhe; Chang, Hong

    2009-02-01

    The grain size and palinology of sediment and the frequency of 14C dada provide an integrated reconstruction of the Holocene warm-humid phases of the North China Plain. Two clear intense and long-lasting warm-humid phases were identified by comprehensive research in this region. The first phase was dated back to the early Holocene (9 000-7 000 a BP), and the second was centered at 5 000-3 000 a BP. The warm-humid episode between 9 000 and 7 000 a BP was also recognized at other sites showing global climatic trends rather than local events. Compared with the concern to the warm-humid phase of the early Holocene, the second one was not paid enough attention in the last few decades. The compilation of the Holocene paleoclimate data suggests that perhaps the second warm-humid phase was pervasive in monsoon region of China. In perspective of environmental archaeology, much attention should be devoted to it, because the flourish and adaptation of the Neolithic cultures and the building up of the first state seem to corresponding to the general warm-humid climatic conditions of this period. In addition, a warm-humid interval at 7 200-6 500 a BP was recognized by the grain size data from three sites. However, this warm-humid event was not shown in pollen assemblage and temporal distribution of 14C data. Perhaps, the resolution for climatic reconstruction from pollen and temporal distribution of 14C data cited here is relatively low and small-amplitude and short-period climatic events cannot be well reflected by the data. Due to the difference in locality and elevation of sampling site, as well as in resolution of proxy records, it is difficult to make precise correlation. Further work is needed in the future.

  12. Roller compaction: Effect of relative humidity of lactose powder.

    Science.gov (United States)

    Omar, Chalak S; Dhenge, Ranjit M; Palzer, Stefan; Hounslow, Michael J; Salman, Agba D

    2016-09-01

    The effect of storage at different relative humidity conditions, for various types of lactose, on roller compaction behaviour was investigated. Three types of lactose were used in this study: anhydrous lactose (SuperTab21AN), spray dried lactose (SuperTab11SD) and α-lactose monohydrate 200M. These powders differ in their amorphous contents, due to different manufacturing processes. The powders were stored in a climatic chamber at different relative humidity values ranging from 10% to 80% RH. It was found that the roller compaction behaviour and ribbon properties were different for powders conditioned to different relative humidities. The amount of fines produced, which is undesirable in roller compaction, was found to be different at different relative humidity. The minimum amount of fines produced was found to be for powders conditioned at 20-40% RH. The maximum amount of fines was produced for powders conditioned at 80% RH. This was attributed to the decrease in powder flowability, as indicated by the flow function coefficient ffc and the angle of repose. Particle Image Velocimetry (PIV) was also applied to determine the velocity of primary particles during ribbon production, and it was found that the velocity of the powder during the roller compaction decreased with powders stored at high RH. This resulted in less powder being present in the compaction zone at the edges of the rollers, which resulted in ribbons with a smaller overall width. The relative humidity for the storage of powders has shown to have minimal effect on the ribbon tensile strength at low RH conditions (10-20%). The lowest tensile strength of ribbons produced from lactose 200M and SD was for powders conditioned at 80% RH, whereas, ribbons produced from lactose 21AN at the same condition of 80% RH showed the highest tensile strength. The storage RH range 20-40% was found to be an optimum condition for roll compacting three lactose powders, as it resulted in a minimum amount of fines in the

  13. A comparison of large scale changes in surface humidity over land in observations and CMIP3 general circulation models

    International Nuclear Information System (INIS)

    Willett, Katharine M; Thorne, Peter W; Jones, Philip D; Gillett, Nathan P

    2010-01-01

    Observed changes in the HadCRUH global land surface specific humidity and CRUTEM3 surface temperature from 1973 to 1999 are compared to CMIP3 archive climate model simulations with 20th Century forcings. Observed humidity increases are proportionately largest in the Northern Hemisphere, especially in winter. At the largest spatio-temporal scales moistening is close to the Clausius-Clapeyron scaling of the saturated specific humidity (∼7% K -1 ). At smaller scales in water-limited regions, changes in specific humidity are strongly inversely correlated with total changes in temperature. Conversely, in some regions increases are faster than implied by the Clausius-Clapeyron relation. The range of climate model specific humidity seasonal climatology and variance encompasses the observations. The models also reproduce the magnitude of observed interannual variance over all large regions. Observed and modelled trends and temperature-humidity relationships are comparable except for the extratropical Southern Hemisphere where observations exhibit no trend but models exhibit moistening. This may arise from: long-term biases remaining in the observations; the relative paucity of observational coverage; or common model errors. The overall degree of consistency of anthropogenically forced models with the observations is further evidence for anthropogenic influence on the climate of the late 20th century.

  14. Proposition of Regression Equations to Determine Outdoor Thermal Comfort in Tropical and Humid Environment

    Directory of Open Access Journals (Sweden)

    Sangkertadi Sangkertadi

    2012-05-01

    Full Text Available This study is about field experimentation in order to construct regression equations of perception of thermalcomfort for outdoor activities under hot and humid environment. Relationships between thermal-comfort perceptions, micro climate variables (temperatures and humidity and body parameters (activity, clothing, body measure have been observed and analyzed. 180 adults, men, and women participated as samples/respondents. This study is limited for situation where wind velocity is about 1 m/s, which touch the body of the respondents/samples. From questionnaires and field measurements, three regression equations have been developed, each for activity of normal walking, brisk walking, and sitting.

  15. Interannual variations in the zonal asymmetry of the subpolar latitudes total ozone column during the austral spring

    Directory of Open Access Journals (Sweden)

    Eduardo A. Agosta

    2010-06-01

    Full Text Available The Southern Hemisphere midlatitude Total Ozone Column (TOC shows a horseshoe like structure with a minimum which appears to have two preferential extreme positions during October: one, near southern South America, the other, near the Greenwich Meridian approximately. The interannual zonal ozone asymmetry exists independently of the variations induced by the 11-year solar cycle, the Quasi-Biennial Oscillation (QBO and planetary wave activity inducing the Brewer-Dobson circulation. The classification and climatological composition of these two extreme ozone-minimum positions allows for the observations of statistically significant patterns in geopotential height and zonal winds associated with the quasi-stationary wave 1, extending throughout lower stratosphere. The changes in the quasi-stationary wave 1 associated with the extreme TOC positions appear to have sinks and sources determining transient interactions between troposphere and the stratosphere. Thus, distinct climate states in the troposphere seem to be dynamically linked with the state of the stratosphere and ozone layer. The migration of the TOC trough from southern South America to the east during the 1990s can be related to changes in the troposphere/stratosphere coupling through changes in the Southern Annular Mode variability in spring.La Columna Total de Ozono (CTO de las latitudes medias del Hemisferio Sur muestra una estructura de herradura con un mínimo que muestra tener dos posiciones preferenciales extremas durante octubre: uno, en las cercanías del sur de Sudamérica, y el otro, cerca del meridiano de Greenwich. La asimetría zonal de ozono existe independientemente de las variaciones inducidas por el ciclo solar de 11 años, la Oscilación Cuasi-Bianual (QBO y la actividad de onda planetaria asociada a la circulación de Brewer-Dobson. La clasificación y composición climatológica de estas dos situaciones longitudinalmente extremas de mínimo de ozono permite observar

  16. Humidity effects on wire insulation breakdown strength.

    Energy Technology Data Exchange (ETDEWEB)

    Appelhans, Leah

    2013-08-01

    Methods for the testing of the dielectric breakdown strength of insulation on metal wires under variable humidity conditions were developed. Two methods, an ASTM method and the twisted pair method, were compared to determine if the twisted pair method could be used for determination of breakdown strength under variable humidity conditions. It was concluded that, although there were small differences in outcomes between the two testing methods, the non-standard method (twisted pair) would be appropriate to use for further testing of the effects of humidity on breakdown performance. The dielectric breakdown strength of 34G copper wire insulated with double layer Poly-Thermaleze/Polyamide-imide insulation was measured using the twisted pair method under a variety of relative humidity (RH) conditions and exposure times. Humidity at 50% RH and below was not found to affect the dielectric breakdown strength. At 80% RH the dielectric breakdown strength was significantly diminished. No effect for exposure time up to 140 hours was observed at 50 or 80%RH.

  17. 40 CFR 89.326 - Engine intake air humidity measurement.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air humidity measurement... Test Equipment Provisions § 89.326 Engine intake air humidity measurement. (a) Humidity conditioned air... type of intake air supply, the humidity measurements must be made within the intake air supply system...

  18. 40 CFR 91.310 - Engine intake air humidity measurement.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air humidity measurement... Provisions § 91.310 Engine intake air humidity measurement. This section refers to engines which are supplied... air, the ambient testcell humidity measurement may be used. (a) Humidity conditioned air supply. Air...

  19. 40 CFR 90.310 - Engine intake air humidity measurement.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air humidity measurement... Emission Test Equipment Provisions § 90.310 Engine intake air humidity measurement. This section refers to... for the engine intake air, the ambient test cell humidity measurement may be used. (a) Humidity...

  20. Upper limits for air humidity based on human comfort

    DEFF Research Database (Denmark)

    Toftum, Jørn; Fanger, Povl Ole; Jørgensen, Anette S.

    1998-01-01

    respiratory cooling. Human subjects perceived the condition of their skin to be less acceptable with increasing skin humidity. Inhaled air was rated warmer, more stuffy and less acceptable with increasing air humidity and temperature. Based on the subjects' comfort responses, new upper limits for air humidity......The purpose of this study was to verify the hypothesis that insufficient respiratory cooling and a high level of skin humidity are two reasons for thermal discomfort at high air humidities, and to prescribe upper limits for humidity based on discomfort due to elevated skin humidity and insufficient...

  1. All-Optical Graphene Oxide Humidity Sensors

    Directory of Open Access Journals (Sweden)

    Weng Hong Lim

    2014-12-01

    Full Text Available The optical characteristics of graphene oxide (GO were explored to design and fabricate a GO-based optical humidity sensor. GO film was coated onto a SU8 polymer channel waveguide using the drop-casting technique. The proposed sensor shows a high TE-mode absorption at 1550 nm. Due to the dependence of the dielectric properties of the GO film on water content, this high TE-mode absorption decreases when the ambient relative humidity increases. The proposed sensor shows a rapid response (<1 s to periodically interrupted humid air flow. The transmission of the proposed sensor shows a linear response of 0.553 dB/% RH in the range of 60% to 100% RH.

  2. All-optical graphene oxide humidity sensors.

    Science.gov (United States)

    Lim, Weng Hong; Yap, Yuen Kiat; Chong, Wu Yi; Ahmad, Harith

    2014-12-17

    The optical characteristics of graphene oxide (GO) were explored to design and fabricate a GO-based optical humidity sensor. GO film was coated onto a SU8 polymer channel waveguide using the drop-casting technique. The proposed sensor shows a high TE-mode absorption at 1550 nm. Due to the dependence of the dielectric properties of the GO film on water content, this high TE-mode absorption decreases when the ambient relative humidity increases. The proposed sensor shows a rapid response (<1 s) to periodically interrupted humid air flow. The transmission of the proposed sensor shows a linear response of 0.553 dB/% RH in the range of 60% to 100% RH.

  3. Use of personalized ventilation for improving health, comfort, and performance at high room temperature and humidity

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Skwarczynski, Mariusz; Kaczmarczyk, J.

    2013-01-01

    in five 4-h experiments in a climate chamber. Under the conditions with PV, the subjects were able to control the rate and direction of the supplied personalized flow of clean air. Subjective responses were collected through questionnaires. During all exposures, the subjects were occupied with tasks used......The effect of personalized ventilation (PV) on people's health, comfort, and performance in a warm and humid environment (26 and 28°C at 70% relative humidity) was studied and compared with their responses in a comfortable environment (23°C and 40% relative humidity). Thirty subjects participated...... to assess their performance. Objective measures of tear film stability, concentration of stress biomarkers in saliva, and eye blinking rate were taken. Using PV significantly improved the perceived air quality (PAQ) and thermal sensation and decreased the intensity of Sick Building Syndrome (SBS) symptoms...

  4. Influence of air humidity on polymeric microresonators

    International Nuclear Information System (INIS)

    Schmid, S; Kühne, S; Hierold, C

    2009-01-01

    The influence of air humidity on polymeric microresonators is investigated by means of three different resonator types. SU-8 microbeams, SU-8 microstrings and a silicon micromirror with SU-8 hinges are exposed to relative humidities between 3% and 60%. The shifts of the resonant frequencies as a function of the relative humidity (RH) are explained based on mechanical models which are extended with water absorption models in polymer materials. The dominant effect causing the resonant frequency change is evaluated for each structure type. The eigenfrequency of the microstrings and the micromirror in the out-of-plane mode, which both mainly are defined by the pre-stress of the polymeric structures, are found to be highly sensitive to changes of air humidity. The humidity-induced (hygrometric) volume expansion reversibly reduces the pre-stress which results in relative frequency changes of up to 0.78%/%RH for the microstrings. A maximum coefficient of humidity-induced volume expansion for SU-8 of α hyg = 52.3 ppm/%RH is evaluated by fitting the data with the analytical model. It was found that microstrings that were stored at 150 °C over 150 h are more moisture sensitive compared to structures that were stored at room temperature. For the SU-8 microbeams and the micromirror in the tilt mode, the eigenfrequency is mainly defined by the modulus of the polymer material. The measured relative resonant frequency changes were below 1% for the given RH range. For low RH values, antiplasticization is observed (the modulus increases) followed by a plasticization for increasing RH values

  5. VEMAP 2: Monthly Ecosystem Model Responses to U.S. Climate Change, 1994-2100

    Data.gov (United States)

    National Aeronautics and Space Administration — Phase 2 developed historical (1895-1993) gridded data sets of climate (temperature, precipitation, solar radiation, humidity, and wind speed) and projected...

  6. Humidity fluctuations in the marine boundary layer measured at a coastal site with an infrared humidity sensor

    DEFF Research Database (Denmark)

    Sempreviva, A.M.; Gryning, Sven-Erik

    1996-01-01

    An extensive set of humidity turbulence data has been analyzed from 22-m height in the marine boundary layer. Fluctuations of humidity were measured by an ''OPHIR'', an infrared humidity sensor with a 10 Hz scanning frequency and humidity spectra were produced. The shapes of the normalized spectra...... follow the established similarity functions. However the 10-min time averaged measurements underestimate the value of the absolute humidity. The importance of the humidity flux contribution in a marine environment in calculating the Obukhov stability length has been studied. Deviations from Monin......-Obukhov similarity theory seem to be connected to a low correlation between humidity and temperature....

  7. Noise performance of microwave humidity sounders over their lifetime

    Science.gov (United States)

    Hans, Imke; Burgdorf, Martin; John, Viju O.; Mittaz, Jonathan; Buehler, Stefan A.

    2017-12-01

    The microwave humidity sounders Special Sensor Microwave Water Vapor Profiler (SSMT-2), Advanced Microwave Sounding Unit-B (AMSU-B) and Microwave Humidity Sounder (MHS) to date have been providing data records for 25 years. So far, the data records lack uncertainty information essential for constructing consistent long time data series. In this study, we assess the quality of the recorded data with respect to the uncertainty caused by noise. We calculate the noise on the raw calibration counts from the deep space views (DSVs) of the instrument and the noise equivalent differential temperature (NEΔT) as a measure for the radiometer sensitivity. For this purpose, we use the Allan deviation that is not biased from an underlying varying mean of the data and that has been suggested only recently for application in atmospheric remote sensing. Moreover, we use the bias function related to the Allan deviation to infer the underlying spectrum of the noise. As examples, we investigate the noise spectrum in flight for some instruments. For the assessment of the noise evolution in time, we provide a descriptive and graphical overview of the calculated NEΔT over the life span of each instrument and channel. This overview can serve as an easily accessible information for users interested in the noise performance of a specific instrument, channel and time. Within the time evolution of the noise, we identify periods of instrumental degradation, which manifest themselves in an increasing NEΔT, and periods of erratic behaviour, which show sudden increases of NEΔT interrupting the overall smooth evolution of the noise. From this assessment and subsequent exclusion of the aforementioned periods, we present a chart showing available data records with NEΔT processing to provide input values for the uncertainty propagation in the generation of a new set of Fundamental Climate Data Records (FCDRs) that are currently produced in the project Fidelity and Uncertainty in Climate data

  8. Seasonality of absolute humidity explains seasonality of influenza-like illness in Vietnam.

    Science.gov (United States)

    Thai, Pham Quang; Choisy, Marc; Duong, Tran Nhu; Thiem, Vu Dinh; Yen, Nguyen Thu; Hien, Nguyen Tran; Weiss, Daniel J; Boni, Maciej F; Horby, Peter

    2015-12-01

    Experimental and ecological studies have shown the role of climatic factors in driving the epidemiology of influenza. In particular, low absolute humidity (AH) has been shown to increase influenza virus transmissibility and has been identified to explain the onset of epidemics in temperate regions. Here, we aim to study the potential climatic drivers of influenza-like illness (ILI) epidemiology in Vietnam, a tropical country characterized by a high diversity of climates. We specifically focus on quantifying and explaining the seasonality of ILI. We used 18 years (1993-2010) of monthly ILI notifications aggregated by province (52) and monthly climatic variables (minimum, mean, maximum temperatures, absolute and relative humidities, rainfall and hours of sunshine) from 67 weather stations across Vietnam. Seasonalities were quantified from global wavelet spectra, using the value of the power at the period of 1 year as a measure of the intensity of seasonality. The 7 climatic time series were characterized by 534 summary statistics which were entered into a regression tree to identify factors associated with the seasonality of AH. Results were extrapolated to the global scale using simulated climatic times series from the NCEP/NCAR project. The intensity of ILI seasonality in Vietnam is best explained by the intensity of AH seasonality. We find that ILI seasonality is weak in provinces experiencing weak seasonal fluctuations in AH (annual power power >17.6). In Vietnam, AH and ILI are positively correlated. Our results identify a role for AH in driving the epidemiology of ILI in a tropical setting. However, in contrast to temperate regions, high rather than low AH is associated with increased ILI activity. Fluctuation in AH may be the climate factor that underlies and unifies the seasonality of ILI in both temperate and tropical regions. Alternatively, the mechanism of action of AH on disease transmission may be different in cold-dry versus hot-humid settings

  9. Humidity May Modify the Relationship between Temperature and Cardiovascular Mortality in Zhejiang Province, China.

    Science.gov (United States)

    Zeng, Jie; Zhang, Xuehai; Yang, Jun; Bao, Junzhe; Xiang, Hao; Dear, Keith; Liu, Qiyong; Lin, Shao; Lawrence, Wayne R; Lin, Aihua; Huang, Cunrui

    2017-11-14

    Background : The evidence of increased mortality attributable to extreme temperatures is widely characterized in climate-health studies. However, few of these studies have examined the role of humidity on temperature-mortality association. We investigated the joint effect between temperature and humidity on cardiovascular disease (CVD) mortality in Zhejiang Province, China. Methods : We collected data on daily meteorological and CVD mortality from 11 cities in Zhejiang Province during 2010-2013. We first applied time-series Poisson regression analysis within the framework of distributed lag non-linear models to estimate the city-specific effect of temperature and humidity on CVD mortality, after controlling for temporal trends and potential confounding variables. We then applied a multivariate meta-analytical model to pool the effect estimates in the 11 cities to generate an overall provincial estimate. The joint effects between them were calculated by the attributable fraction (AF). The analyses were further stratified by gender, age group, education level, and location of cities. Results : In total, 120,544 CVD deaths were recorded in this study. The mean values of temperature and humidity were 17.6 °C and 72.3%. The joint effect between low temperature and high humidity had the greatest impact on the CVD death burden over a lag of 0-21 days with a significant AF of 31.36% (95% eCI: 14.79-38.41%), while in a condition of low temperature and low humidity with a significant AF of 16.74% (95% eCI: 0.89, 24.44). The AFs were higher at low temperature and high humidity in different subgroups. When considering the levels of humidity, the AFs were significant at low temperature and high humidity for males, youth, those with a low level of education, and coastal area people. Conclusions : The combination of low temperature and high humidity had the greatest impact on the CVD death burden in Zhejiang Province. This evidence has important implications for developing CVD

  10. Humidity May Modify the Relationship between Temperature and Cardiovascular Mortality in Zhejiang Province, China

    Science.gov (United States)

    Zeng, Jie; Zhang, Xuehai; Yang, Jun; Bao, Junzhe; Dear, Keith; Liu, Qiyong; Lin, Shao; Lin, Aihua; Huang, Cunrui

    2017-01-01

    Background: The evidence of increased mortality attributable to extreme temperatures is widely characterized in climate-health studies. However, few of these studies have examined the role of humidity on temperature-mortality association. We investigated the joint effect between temperature and humidity on cardiovascular disease (CVD) mortality in Zhejiang Province, China. Methods: We collected data on daily meteorological and CVD mortality from 11 cities in Zhejiang Province during 2010–2013. We first applied time-series Poisson regression analysis within the framework of distributed lag non-linear models to estimate the city-specific effect of temperature and humidity on CVD mortality, after controlling for temporal trends and potential confounding variables. We then applied a multivariate meta-analytical model to pool the effect estimates in the 11 cities to generate an overall provincial estimate. The joint effects between them were calculated by the attributable fraction (AF). The analyses were further stratified by gender, age group, education level, and location of cities. Results: In total, 120,544 CVD deaths were recorded in this study. The mean values of temperature and humidity were 17.6 °C and 72.3%. The joint effect between low temperature and high humidity had the greatest impact on the CVD death burden over a lag of 0–21 days with a significant AF of 31.36% (95% eCI: 14.79–38.41%), while in a condition of low temperature and low humidity with a significant AF of 16.74% (95% eCI: 0.89, 24.44). The AFs were higher at low temperature and high humidity in different subgroups. When considering the levels of humidity, the AFs were significant at low temperature and high humidity for males, youth, those with a low level of education, and coastal area people. Conclusions: The combination of low temperature and high humidity had the greatest impact on the CVD death burden in Zhejiang Province. This evidence has important implications for developing CVD

  11. Humidity May Modify the Relationship between Temperature and Cardiovascular Mortality in Zhejiang Province, China

    Directory of Open Access Journals (Sweden)

    Jie Zeng

    2017-11-01

    Full Text Available Background: The evidence of increased mortality attributable to extreme temperatures is widely characterized in climate-health studies. However, few of these studies have examined the role of humidity on temperature-mortality association. We investigated the joint effect between temperature and humidity on cardiovascular disease (CVD mortality in Zhejiang Province, China. Methods: We collected data on daily meteorological and CVD mortality from 11 cities in Zhejiang Province during 2010–2013. We first applied time-series Poisson regression analysis within the framework of distributed lag non-linear models to estimate the city-specific effect of temperature and humidity on CVD mortality, after controlling for temporal trends and potential confounding variables. We then applied a multivariate meta-analytical model to pool the effect estimates in the 11 cities to generate an overall provincial estimate. The joint effects between them were calculated by the attributable fraction (AF. The analyses were further stratified by gender, age group, education level, and location of cities. Results: In total, 120,544 CVD deaths were recorded in this study. The mean values of temperature and humidity were 17.6 °C and 72.3%. The joint effect between low temperature and high humidity had the greatest impact on the CVD death burden over a lag of 0–21 days with a significant AF of 31.36% (95% eCI: 14.79–38.41%, while in a condition of low temperature and low humidity with a significant AF of 16.74% (95% eCI: 0.89, 24.44. The AFs were higher at low temperature and high humidity in different subgroups. When considering the levels of humidity, the AFs were significant at low temperature and high humidity for males, youth, those with a low level of education, and coastal area people. Conclusions: The combination of low temperature and high humidity had the greatest impact on the CVD death burden in Zhejiang Province. This evidence has important implications

  12. Humidity sensing characteristics of hydrotungstite thin films

    Indian Academy of Sciences (India)

    The electrical conductivity of the films is observed to vary with humidity and selectively show high sensitivity to moisture at room temperature. In order to understand the mechanism of sensing, the films were examined by X-ray diffraction at elevated temperatures and in controlled atmospheres. Based on these observations ...

  13. Soil erosion in humid regions: a review

    Science.gov (United States)

    Daniel J. Holz; Karl W.J. Williard; Pamela J. Edwards; Jon E. Schoonover

    2015-01-01

    Soil erosion has significant implications for land productivity and surface water quality, as sediment is the leading water pollutant worldwide. Here, erosion processes are defined. The dominant factors influencing soil erosion in humid areas are reviewed, with an emphasis on the roles of precipitation, soil moisture, soil porosity, slope steepness and length,...

  14. Biochars as Innovative Humidity Sensing Materials

    Directory of Open Access Journals (Sweden)

    Daniele Ziegler

    2017-12-01

    Full Text Available In this work, biochar-based humidity sensors were prepared by drop-coating technique. Polyvinylpyrrolidone (PVP was added as an organic binder to improve the adhesion of the sensing material onto ceramic substrates having platinum electrodes. Two biochars obtained from different precursors were used. The sensors were tested toward relative humidity (RH at room temperature and showed a response starting around 5 RH%, varying the impedance of 2 orders of magnitude after exposure to almost 100% relative humidity. In both cases, biochar materials are behaving as p-type semiconductors under low amounts of humidity. On the contrary, for higher RH values, the impedance decreased due to water molecules adsorption. When PVP is added to SWP700 biochar, n-p heterojunctions are formed between the two semiconductors, leading to a higher sensitivity at low RH values for the sensors SWP700-10% PVP and SWP700-20% PVP with respect to pure SWP700 sensor. Finally, response and recovery times were both reasonably fast (in the order of 1 min.

  15. Recent Developments in Fiber Optics Humidity Sensors.

    Science.gov (United States)

    Ascorbe, Joaquin; Corres, Jesus M; Arregui, Francisco J; Matias, Ignacio R

    2017-04-19

    A wide range of applications such as health, human comfort, agriculture, food processing and storage, and electronic manufacturing, among others, require fast and accurate measurement of humidity. Sensors based on optical fibers present several advantages over electronic sensors and great research efforts have been made in recent years in this field. The present paper reports the current trends of optical fiber humidity sensors. The evolution of optical structures developed towards humidity sensing, as well as the novel materials used for this purpose, will be analyzed. Well-known optical structures, such as long-period fiber gratings or fiber Bragg gratings, are still being studied towards an enhancement of their sensitivity. Sensors based on lossy mode resonances constitute a platform that combines high sensitivity with low complexity, both in terms of their fabrication process and the equipment required. Novel structures, such as resonators, are being studied in order to improve the resolution of humidity sensors. Moreover, recent research on polymer optical fibers suggests that the sensitivity of this kind of sensor has not yet reached its limit. Therefore, there is still room for improvement in terms of sensitivity and resolution.

  16. The influence of humidity fluxes on offshore wind speed profiles

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca Jane; Sempreviva, Anna Maria; Pryor, Sara

    2010-01-01

    extrapolation from lower measurements. With humid conditions and low mechanical turbulence offshore, deviations from the traditional logarithmic wind speed profile become significant and stability corrections are required. This research focuses on quantifying the effect of humidity fluxes on stability corrected...... wind speed profiles. The effect on wind speed profiles is found to be important in stable conditions where including humidity fluxes forces conditions towards neutral. Our results show that excluding humidity fluxes leads to average predicted wind speeds at 150 m from 10 m which are up to 4% higher...... than if humidity fluxes are included, and the results are not very sensitive to the method selected to estimate humidity fluxes....

  17. Fast humidity sensors based on CeO2 nanowires

    International Nuclear Information System (INIS)

    Fu, X Q; Wang, C; Yu, H C; Wang, Y G; Wang, T H

    2007-01-01

    Fast humidity sensors are reported that are based on CeO 2 nanowires synthesized by a hydrothermal method. Both the response and recovery time are about 3 s, and are independent of the humidity. The sensitivity increases gradually as the humidity increases, and is up to 85 at 97% RH. The resistance decreases exponentially with increasing humidity, implying ion-type conductivity as the humidity sensing mechanism. A model based on the morphology and surface energy of the nanowires is given to explain these results further. Our experimental results indicate a pathway to improving the performance of humidity sensors

  18. Seasonality of absolute humidity explains seasonality of influenza-like illness in Vietnam

    Directory of Open Access Journals (Sweden)

    Pham Quang Thai

    2015-12-01

    Conclusions: Our results identify a role for AH in driving the epidemiology of ILI in a tropical setting. However, in contrast to temperate regions, high rather than low AH is associated with increased ILI activity. Fluctuation in AH may be the climate factor that underlies and unifies the seasonality of ILI in both temperate and tropical regions. Alternatively, the mechanism of action of AH on disease transmission may be different in cold-dry versus hot-humid settings.

  19. Trends in mean maximum temperature, mean minimum temperature and mean relative humidity for Lautoka, Fiji during 2003 – 2013

    Directory of Open Access Journals (Sweden)

    Syed S. Ghani

    2017-12-01

    Full Text Available The current work observes the trends in Lautoka’s temperature and relative humidity during the period 2003 – 2013, which were analyzed using the recently updated data obtained from Fiji Meteorological Services (FMS. Four elements, mean maximum temperature, mean minimum temperature along with diurnal temperature range (DTR and mean relative humidity are investigated. From 2003–2013, the annual mean temperature has been enhanced between 0.02 and 0.080C. The heating is more in minimum temperature than in maximum temperature, resulting in a decrease of diurnal temperature range. The statistically significant increase was mostly seen during the summer months of December and January. Mean Relative Humidity has also increased from 3% to 8%. The bases of abnormal climate conditions are also studied. These bases were defined with temperature or humidity anomalies in their appropriate time sequences. These established the observed findings and exhibited that climate has been becoming gradually damper and heater throughout Lautoka during this period. While we are only at an initial phase in the probable inclinations of temperature changes, ecological reactions to recent climate change are already evidently noticeable. So it is proposed that it would be easier to identify climate alteration in a small island nation like Fiji.

  20. Impact of temperature and humidity on acceptability of indoor air quality during immediate and longer whole-body exposures

    DEFF Research Database (Denmark)

    Fang, Lei; Clausen, Geo; Fanger, Povl Ole

    1997-01-01

    Acceptability of clean air and air polluted by building materials was studied in climate chambers with different levels of air temperature and humidity in the ranges 18-28°C and 30-70%. The immediate acceptability after entering a chamber and the acceptability during a 20-minute whole-body exposu...

  1. Solar-Powered, Liquid-Desiccant Air Conditioner for Low-Electricity Humidity Control: Report and Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Dean, J.; Kozubal, E.; Herrmann, L.; Miller, J.; Lowenstein, A.; Barker, G.; Slayzak, S.

    2012-11-01

    The primary objective of this project was to demonstrate the capabilities of a new high-performance, liquid-desiccant dedicated outdoor air system (DOAS) to enhance cooling efficiency and comfort in humid climates while substantially reducing electric peak demand at Tyndall Air Force Base (AFB), which is 12 miles east of Panama City, Florida.

  2. Dynamic temperature and humidity environmental profiles: impact for future emergency and disaster preparedness and response.

    Science.gov (United States)

    Ferguson, William J; Louie, Richard F; Tang, Chloe S; Paw U, Kyaw Tha; Kost, Gerald J

    2014-02-01

    During disasters and complex emergencies, environmental conditions can adversely affect the performance of point-of-care (POC) testing. Knowledge of these conditions can help device developers and operators understand the significance of temperature and humidity limits necessary for use of POC devices. First responders will benefit from improved performance for on-site decision making. To create dynamic temperature and humidity profiles that can be used to assess the environmental robustness of POC devices, reagents, and other resources (eg, drugs), and thereby, to improve preparedness. Surface temperature and humidity data from the National Climatic Data Center (Asheville, North Carolina USA) was obtained, median hourly temperature and humidity were calculated, and then mathematically stretched profiles were created to include extreme highs and lows. Profiles were created for: (1) Banda Aceh, Indonesia at the time of the 2004 Tsunami; (2) New Orleans, Louisiana USA just before and after Hurricane Katrina made landfall in 2005; (3) Springfield, Massachusetts USA for an ambulance call during the month of January 2009; (4) Port-au-Prince, Haiti following the 2010 earthquake; (5) Sendai, Japan for the March 2011 earthquake and tsunami with comparison to the colder month of January 2011; (6) New York, New York USA after Hurricane Sandy made landfall in 2012; and (7) a 24-hour rescue from Hawaii USA to the Marshall Islands. Profiles were validated by randomly selecting 10 days and determining if (1) temperature and humidity points fell inside and (2) daily variations were encompassed. Mean kinetic temperatures (MKT) were also assessed for each profile. Profiles accurately modeled conditions during emergency and disaster events and enclosed 100% of maximum and minimum temperature and humidity points. Daily variations also were represented well with 88.6% (62/70) of temperature readings and 71.1% (54/70) of relative humidity readings falling within diurnal patterns. Days

  3. Wireless sensor for temperature and humidity measurement

    Science.gov (United States)

    Drumea, Andrei; Svasta, Paul

    2010-11-01

    Temperature and humidity sensors have a broad range of applications, from heating and ventilation of houses to controlled drying of fruits, vegetables or meat in food industry. Modern sensors are integrated devices, usually MEMS, factory-calibrated and with digital output of measured parameters. They can have power down modes for reduced energy consumption. Such an integrated device allows the implementation of a battery powered wireless sensor when coupled with a low power microcontroller and a radio subsystem. A radio sensor can work independently or together with others in a radio network. Presented paper focuses mainly on measurement and construction aspects of sensors for temperature and humidity designed and implemented by authors; network aspects (communication between two or more sensors) are not analyzed.

  4. Humidity-regulated dormancy onset in the Fabaceae: a conceptual model and its ecological implications for the Australian wattle Acacia saligna

    Science.gov (United States)

    Tozer, Mark G.; Ooi, Mark K. J.

    2014-01-01

    Background and aims Seed dormancy enhances fitness by preventing seeds from germinating when the probability of seedling survival and recruitment is low. The onset of physical dormancy is sensitive to humidity during ripening; however, the implications of this mechanism for seed bank dynamics have not been quantified. This study proposes a model that describes how humidity-regulated dormancy onset may control the accumulation of a dormant seed bank, and seed experiments are conducted to calibrate the model for an Australian Fabaceae, Acacia saligna. The model is used to investigate the impact of climate on seed dormancy and to forecast the ecological implications of human-induced climate change. Methods The relationship between relative humidity and dormancy onset was quantified under laboratory conditions by exposing freshly matured non-dormant seeds to constant humidity levels for fixed durations. The model was field-calibrated by measuring the response of seeds exposed to naturally fluctuating humidity. The model was applied to 3-hourly records of humidity spanning the period 1972–2007 in order to estimate both temporal variability in dormancy and spatial variability attributable to climatic differences among populations. Climate change models were used to project future changes in dormancy onset. Key Results A sigmoidal relationship exists between dormancy and humidity under both laboratory and field conditions. Seeds ripened under field conditions became dormant following very short exposure to low humidity (<20 %). Prolonged exposure at higher humidity did not increase dormancy significantly. It is predicted that populations growing in a temperate climate produce 33–55 % fewer dormant seeds than those in a Mediterranean climate; however, dormancy in temperate populations is predicted to increase as a result of climate change. Conclusions Humidity-regulated dormancy onset may explain observed variation in physical dormancy. The model offers a systematic

  5. Humidity-regulated dormancy onset in the Fabaceae: a conceptual model and its ecological implications for the Australian wattle Acacia saligna.

    Science.gov (United States)

    Tozer, Mark G; Ooi, Mark K J

    2014-09-01

    Seed dormancy enhances fitness by preventing seeds from germinating when the probability of seedling survival and recruitment is low. The onset of physical dormancy is sensitive to humidity during ripening; however, the implications of this mechanism for seed bank dynamics have not been quantified. This study proposes a model that describes how humidity-regulated dormancy onset may control the accumulation of a dormant seed bank, and seed experiments are conducted to calibrate the model for an Australian Fabaceae, Acacia saligna. The model is used to investigate the impact of climate on seed dormancy and to forecast the ecological implications of human-induced climate change. The relationship between relative humidity and dormancy onset was quantified under laboratory conditions by exposing freshly matured non-dormant seeds to constant humidity levels for fixed durations. The model was field-calibrated by measuring the response of seeds exposed to naturally fluctuating humidity. The model was applied to 3-hourly records of humidity spanning the period 1972-2007 in order to estimate both temporal variability in dormancy and spatial variability attributable to climatic differences among populations. Climate change models were used to project future changes in dormancy onset. A sigmoidal relationship exists between dormancy and humidity under both laboratory and field conditions. Seeds ripened under field conditions became dormant following very short exposure to low humidity (humidity did not increase dormancy significantly. It is predicted that populations growing in a temperate climate produce 33-55 % fewer dormant seeds than those in a Mediterranean climate; however, dormancy in temperate populations is predicted to increase as a result of climate change. Humidity-regulated dormancy onset may explain observed variation in physical dormancy. The model offers a systematic approach to modelling this variation in population studies. Forecast changes in climate have

  6. Calibration of Relative Humidity Sensors using a Dew Point Generator

    OpenAIRE

    Brooks, Milo

    2010-01-01

    A relative humidity sensor can be calibrated using a dew point generator to continuously supply an air stream of known constant humidity and a temperature chamber to control the dew point and ambient temperature.

  7. Humidity Detection Using Metal Organic Framework Coated on QCM

    KAUST Repository

    Kosuru, Lakshmoji; Bouchaala, Adam M.; Jaber, Nizar; Younis, Mohammad I.

    2016-01-01

    of a quartz crystal microbalance. The resonance frequencies of these sensors with varying relative humidity (RH) from 22% RH to 69% RH are measured using impedance analysis method. The sensitivity, humidity hysteresis, response, and recovery times

  8. Clinker mineral hydration at reduced relative humidities

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede

    1998-01-01

    This report deals with gas phase hydration of pure cement clinker minerals at reduced relative humidities. This is an important subject in relation to modern high performance concrete which may self-desiccate during hydration. In addition the subject has relevance to storage stability where...... prehydration may occur. In the report both theoretical considerations and experimental data are presented. It is suggested that the initiation of hydration during water vapour exposure is nucleation controlled....

  9. Effect of relative humidity on solar potential

    International Nuclear Information System (INIS)

    Soezen, Adnan; Arcaklioglu, Erol

    2005-01-01

    In this study, the effect of relative humidity on solar potential is investigated using artificial neural-networks. Two different models are used to train the neural networks. Meteorological and geographical data (latitude, longitude, altitude, month, mean sunshine-duration, and mean temperature) are used in the input layer of the network (Model 1). But, relative humidity values are added to one network in model (Model 2). In other words, the only difference between the models is relative humidity. New formulae based on meteorological and geographical data, have been developed to determine the solar energy potential in Turkey using the networks' weights for both models. Scaled conjugate gradient (SCG) and Levenberg-Marquardt (LM) learning algorithms and a logistic sigmoid transfer-function were used in the network. The best approach was obtained by the SCG algorithm with nine neurons for both models. Meteorological data for the four years, 2000-2003, for 18 cities (Artvin, Cesme, Bozkurt, Malkara, Florya, Tosya, Kizilcahamam, Yenisehir, Edremit, Gediz, Kangal, Solhan, Ergani, Selcuk, Milas, Seydisehir, Siverek and Kilis) spread over Turkey have been used as data in order to train the neural network. Solar radiation is in output layer. One month for each city was used as test data, and these months have not been used for training. The maximum mean absolute percentage errors (MAPEs) for Tosya are 2.770394% and 2.8597% for Models 1 and 2, respectively. The minimum MAPEs for Seydisehir are 1.055205% and 1.041% with R 2 (99.9862%, 99.9842%) for Models 1 and 2, respectively, in the SCG algorithm with nine neurons. The best value of R 2 for Models 1 and 2 are for Seydisehir. The minimum value of R 2 for Model 1 is 99.8855% for Tosya, and the value for Model 2 is 99.9001% for Yenisehir. Results show that the humidity has only a negligible effect upon the prediction of solar potential using artificial neural-networks

  10. Procedure for drying humidity-containing bodies

    International Nuclear Information System (INIS)

    Johnson, C.R.

    1976-01-01

    The invention concerns a decontamination process for extracting impurities, in particular humidity and gases, from nuclear fuel rods before they are sealed and inserted into the reactor. The fuel rod, which has a small drilling hole, is placed in a low pressure container. The container is filled with a liquid drying agent which washes out the impurities. A dry inert gas (nitrogen, noble gases) is used for rinsing. Alcohols, ketones, methanol, acetone are named as drying agents. (UWI) [de

  11. Relative Humidity in the Tropopause Saturation Layer

    Science.gov (United States)

    Selkirk, H. B.; Schoeberl, M. R.; Pfister, L.; Thornberry, T. D.; Bui, T. V.

    2017-12-01

    The tropical tropopause separates two very different atmospheric regimes: the stable lower stratosphere where the air is both extremely dry and nearly always so, and a transition layer in the uppermost tropical troposphere, where humidity on average increases rapidly downward but can undergo substantial temporal fluctuations. The processes that control the humidity in this layer below the tropopause include convective detrainment (which can result in either a net hydration or dehydration), slow ascent, wave motions and advection. Together these determine the humidity of the air that eventually passes through the tropopause and into the stratosphere, and we refer to this layer as the tropopause saturation layer or TSL. We know from in situ water vapor observations such as Ticosonde's 12-year balloonsonde record at Costa Rica that layers of supersaturation are frequently observed in the TSL. While their frequency is greatest during the local rainy season from June through October, supersaturation is also observed in the boreal winter dry season when deep convection is well south of Costa Rica. In other words, local convection is not a necessary condition for the presence of supersaturation. Furthermore, there are indications from airborne measurements during the recent POSIDON campaign at Guam that if anything deep convection tends to `reset' the TSL locally to a state of just-saturation. Conversely, it may be that layers of supersaturation are the result of slow ascent. To explore these ideas we take Ticosonde water vapor observations from the TSL, stratify them on the basis of relative humidity and report on the differences in the the history of upstream convective influence between supersaturated parcels and those that are not.

  12. Factors controlling upper tropospheric relative humidity

    Directory of Open Access Journals (Sweden)

    B. Kärcher

    2004-03-01

    Full Text Available Factors controlling the distribution of relative humidity in the absence of clouds are examined, with special emphasis on relative humidity over ice (RHI under upper tropospheric and lower stratospheric conditions. Variations of temperature are the key determinant for the distribution of RHI, followed by variations of the water vapor mixing ratio. Multiple humidity modes, generated by mixing of different air masses, may contribute to the overall distribution of RHI, in particular below ice saturation. The fraction of air that is supersaturated with respect to ice is mainly determined by the distribution of temperature. The nucleation of ice in cirrus clouds determines the highest relative humdity that can be measured outside of cirrus clouds. While vertical air motion and ice microphysics determine the slope of the distributions of RHI, as shown in a separate study companion (Haag et al., 2003, clouds are not required to explain the main features of the distributions of RHI below the ice nucleation threshold. Key words. Atmospheric composition and structure (pressure, density and temperature; troposphere – composition and chemistry; general or miscellaneous

  13. Factors controlling upper tropospheric relative humidity

    Directory of Open Access Journals (Sweden)

    B. Kärcher

    2004-03-01

    Full Text Available Factors controlling the distribution of relative humidity in the absence of clouds are examined, with special emphasis on relative humidity over ice (RHI under upper tropospheric and lower stratospheric conditions. Variations of temperature are the key determinant for the distribution of RHI, followed by variations of the water vapor mixing ratio. Multiple humidity modes, generated by mixing of different air masses, may contribute to the overall distribution of RHI, in particular below ice saturation. The fraction of air that is supersaturated with respect to ice is mainly determined by the distribution of temperature. The nucleation of ice in cirrus clouds determines the highest relative humdity that can be measured outside of cirrus clouds. While vertical air motion and ice microphysics determine the slope of the distributions of RHI, as shown in a separate study companion (Haag et al., 2003, clouds are not required to explain the main features of the distributions of RHI below the ice nucleation threshold.

    Key words. Atmospheric composition and structure (pressure, density and temperature; troposphere – composition and chemistry; general or miscellaneous

  14. Humidity effects on hydrophilic film dosimeter systems

    International Nuclear Information System (INIS)

    Gehringer, P.; Eschweiler, H.; Proksch, E.

    1979-11-01

    At dose-rates typical for 60 Co-gamma irradiation sources the radiation response of hexahydroxyethyl pararosanilin cyanide/50μm nylon radachromic films is dependent upon dose-rate as well as upon the moisture content of the film. Under equilibrium moisture conditions, the response measured at 606 nm 24 hours after end of irradiation shows its highest dose-rate dependence at about 32 % r.h. A decrease in dose-rate from 2.8 to 0.039 Gy.s -1 results in decrease in response by 17%. At higher humidities, the sensitivity of the film as well as the rate dependence decreases and at 86% r.h. no discernible dose-rate effect could be found. At nominal 0 % r.h. a second absorption band at 412 nm appears which is converted completely to an additional 606 nm absorption by exposure to a humid atmosphere. After that procedure the resultant response is somewhat lower but shows almost the same dose-rate dependence as at 32% r.h. Preliminary results concerning the influence of humidity on the response of Blue Cellophane are given, too. (author)

  15. Lead Oxide- PbO Humidity Sensor

    Directory of Open Access Journals (Sweden)

    Sk. Khadeer Pasha

    2010-11-01

    Full Text Available Alcohol thermal route has been used to synthesize nanocrystalline PbO at a low temperature of 75 oC using lead acetate. The synthesized PbO (P75 was annealed in the temperatures ranging from 200-500 oC for 2 h to study the effect of crystal structure and phase changes and were labeled as P200, P300, P400 and P500, respectively. X-Ray diffraction and FT-IR spectroscopy were carried out to identify the structural phases and vibrational stretching frequencies respectively. The TEM images revealed the porous nature of P75 sample which is an important criterion for the humidity sensor. The dc resistance measurements were carried out in the relative humidity (RH range 5-98 %. Among the different prepared, P75 possessed the highest humidity sensitivity of 6250, while the heat treated sample P500 have a low sensitivity of 330. The response and recovery characteristics of the maximum sensitivity sample P75 were 170 s and 40 s respectively.

  16. Anoxic conditions drive phosphorus limitation in humid tropical forest soil microorganisms

    Science.gov (United States)

    Gross, A.; Pett-Ridge, J.; Weber, P. K.; Blazewicz, S.; Silver, W. L.

    2017-12-01

    The elemental stoichiometry of carbon (C), nitrogen (N) and phosphorus (P) of soil microorganisms (C:N:P ratios) regulates transfers of energy and nutrients to higher trophic levels. In humid tropical forests that grow on P-depleted soils, the ability of microbes to concentrate P from their surroundings likely plays a critical role in P-retention and ultimately in forest productivity. Models predict that climate change will cause dramatic changes in rainfall patterns in the humid tropics and field studies have shown these changes can affect the redox state of tropical forest soils, influencing soil respiration and biogeochemical cycling. However, the responses of soil microorganisms to changing environmental conditions are not well known. Here, we incubated humid tropical soils under oxic or anoxic conditions with substrates differing in both C:P stoichiometry and lability, to assess how soil microorganisms respond to different redox regimes. We found that under oxic conditions, microbial C:P ratios were similar to the global optimal ratio (55:1), indicating most microbial cells can adapt to persistent aerated conditions in these soils. However, under anoxic conditions, the ability of soil microbes to acquire soil P declined and their C:P ratios shifted away from the optimal ratio. NanoSIMS elemental imaging of single cells extracted from soil revealed that under anoxic conditions, C:P ratios were above the microbial optimal value in 83% of the cells, in comparison to 41% under oxic conditions. These data suggest microbial growth efficiency switched from being energy limited under oxic conditions to P-limited under anoxic conditions, indicating that, microbial growth in low P humid tropical forests soils may be most constrained by P-limitation when conditions are oxygen-limited. We suggest that differential microbial responses to soil redox states could have important implications for productivity of humid tropical forests under future climate scenarios.

  17. Relation of temperature and humidity to the risk of recurrent gout attacks.

    Science.gov (United States)

    Neogi, Tuhina; Chen, Clara; Niu, Jingbo; Chaisson, Christine; Hunter, David J; Choi, Hyon; Zhang, Yuqing

    2014-08-15

    Gout attack risk may be affected by weather (e.g., because of volume depletion). We therefore examined the association of temperature and humidity with the risk of recurrent gout attacks by conducting an internet-based case-crossover study in the United States (in 2003-2010) among subjects with a diagnosis of gout who had 1 or more attacks during 1 year of follow-up. We examined the association of temperature and humidity over the prior 48 hours with the risk of gout attacks using a time-stratified approach and conditional logistic regression. Among 632 subjects with gout, there was a significant dose-response relationship between mean temperature in the prior 48 hours and the risk of subsequent gout attack (P = 0.01 for linear trend). Higher temperatures were associated with approximately 40% higher risk of gout attack compared with moderate temperatures. There was a reverse J-shaped relationship between mean relative humidity and the risk of gout attacks (P = 0.03 for quadratic trend). The combination of high temperature and low humidity had the greatest association (odds ratio = 2.04, 95% confidence interval: 1.26, 3.30) compared with moderate temperature and relative humidity. Thus, high ambient temperature and possibly extremes of humidity were associated with an increased risk of gout attack, despite the likelihood that individuals are often in climate-controlled indoor environments. © The Author 2014. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. 7 CFR 28.301 - Measurement: humidity; temperature.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Measurement: humidity; temperature. 28.301 Section 28... for Length of Staple § 28.301 Measurement: humidity; temperature. The length of staple of any cotton... its fibers under a relative humidity of the atmosphere of 65 percent and a temperature of 70° F. ...

  19. A Standard CMOS Humidity Sensor without Post-Processing

    OpenAIRE

    Nizhnik, Oleg; Higuchi, Kohei; Maenaka, Kazusuke

    2011-01-01

    A 2 ?W power dissipation, voltage-output, humidity sensor accurate to 5% relative humidity was developed using the LFoundry 0.15 ?m CMOS technology without post-processing. The sensor consists of a woven lateral array of electrodes implemented in CMOS top metal, a Intervia Photodielectric 8023?10 humidity-sensitive layer, and a CMOS capacitance to voltage converter.

  20. Sediment Lofting From Melt-Water Generated Turbidity Currents During Heinrich Events as a Tool to Assess Main Sediment Delivery Phases to Small Subpolar Ocean Basins

    Science.gov (United States)

    Hesse, R.

    2009-05-01

    Small subpolar ocean basins such as the Labrador Sea received a major portion (25%) of their sediment fill during the Pleistocene glaciations (less than 5% of the basin's lifetime), but the detailed timing of sediment supply to the basin remained essentially unknown until recently. The main sediment input into the basin was probably not coupled to major glacial cycles and associated sea-level changes but was related to Heinrich events. Discovery of the depositional facies of fine-grained lofted sediment provides a tool which suggests that the parent-currents from which lofting took place may have been sandy-gravelly turbidity currents that built a huge braided abyssal plain in the Labrador Sea (700 by 120 km underlain by 150 m on average of coarse- grained sediment) which is one of the largest sand accumulations (104 km3) on Earth. The facies of lofted sediment consists of stacked layers of graded muds that contain ice-rafted debris (IRD) which impart a bimodal grain-size distribution to the graded muds. The texturally incompatible grain populations of the muds (median size between 4 and 8 micrometers) and the randomly distributed coarse silt and sand-sized IRD require the combination of two transport processes that delivered the populations independently and allowed mixing at the depositional site: (i) sediment rafting by icebergs (dropstones) and (ii) the rise of turbid freshwater plumes out of fresh-water generated turbidity currents. Sediment lofting from turbidity currents is a process that occurs in density currents generated from sediment-laden fresh-water discharges into the sea that can produce reversed buoyancy, as is well known from experiments. When the flows have traveled long enough, their tops will have lost enough sediment by settling so that they become hypopycnal (their density decreasing below that of the ambient seawater) causing the current tops to lift up. The turbid fresh-water clouds buoyantly rise out of the turbidity current to a level of

  1. [Capacity of extensive green roof to retain rainwater runoff in hot and humid region.

    Science.gov (United States)

    Liu, Ming Xin; Dai, Se Ping; Zhou, Tian Yang; Ruan, Lin; Zhang, Qiao Song

    2017-02-01

    The water logging has become the environmental problem of major cities with the sharp increase of impermeable urban pavement as the contributing cause. Abroad, the green roof has been widely used as a practical measure to intercept rainwater, yet the capacity of green roof to retain rainwater varies with climate conditions. As the hot and humid climate zone features high temperature, humidity and precipitation, it is meaningful to study the capacity of green roof to retain rainwater under such climatic condition. In this research, 3 plat forms were set up in Guangzhou in rainy and hot summer to test the capability of simple green roof to retain rainwater runoff, and the efficiency of green roof to retain rainwater under local climate conditions was worked out based on the meteorological observation and data measurement during the 13-month test period. The results showed that the simple green roof with a substrate thickness of 30, 50 and 70 mm could retain 27.2%, 30.9% and 32.1% of precipitation and reduce the average peak value by 18.9%, 26.2% and 27.7%, respectively. Given an urban built-up area of 1035.01 km 2 in Guangzhou and a roof area percentage of approximately 37.3% and assuming the green roofs with 30 mm-thick substrate were applied within the area, the light, medium and heavy rain could be delayed at 72.8%, 22.6% and 17.4%, respectively. Accordingly, the rainwater retained could reach up to 14317×10 4 m 3 . It suggested the great potential of the simple green roof in retaining rainwater. The research could serve as reference for the hot and humid climate zone to alleviate water logging and visualize sponge city construction.

  2. Climate chamber for environmentally controlled laboratory airflow experiments.

    Science.gov (United States)

    Even-Tzur, Nurit; Zaretsky, Uri; Grinberg, Orly; Davidovich, Tomer; Kloog, Yoel; Wolf, Michael; Elad, David

    2010-01-01

    Climate chambers have been widely used in in vitro and in vivo studies which require controlled environmental temperature and humidity conditions. This article describes a new desktop climate chamber that was developed for application of respiratory airflows on cultured nasal epithelial cells (NEC) under controlled temperature and humidity conditions. Flow experiments were performed by connecting the climate chamber to an airflow generator via a flow chamber with cultured NEC. Experiments at two controlled climate conditions, 25 degrees C and 40% relative humidity (RH) and 37 degrees C and 80%RH, were conducted to study mucin secretion from the cultures inresponse to the flow. The new climate chamber is a relatively simple and inexpensive apparatus which can easily be connected to any flow system for climate controlled flow experiments. This chamber can be easily adjusted to various in vitro experiments, as well as to clinical studies with animals or human subjects which require controlled climate conditions.

  3. Determination of equilibrium humidities using temperature and humidity controlled X-ray diffraction (RH-XRD)

    International Nuclear Information System (INIS)

    Linnow, Kirsten; Steiger, Michael

    2007-01-01

    Confined growth of crystals in porous building materials is generally considered to be a major cause of damage. We report on the use of X-ray diffraction under controlled conditions of temperature and relative humidity (RH-XRD) for the investigation of potentially deleterious phase transition reactions. An improved procedure based on rate measurements is used for the accurate and reproducible determination of equilibrium humidities of deliquescence and hydration reactions. The deliquescence humidities of NaCl (75.4 ± 0.5% RH) and Ca(NO 3 ) 2 .4H 2 O (50.8 ± 0.7% RH) at 25 deg. C determined with this improved RH-XRD technique are in excellent agreement with available literature data. Measurement of the hydration of anhydrous Ca(NO 3 ) 2 to form Ca(NO 3 ) 2 .2H 2 O revealed an equilibrium humidity of 10.2 ± 0.3%, which is also in reasonable agreement with available data. In conclusion, dynamic X-ray diffraction measurements are an appropriate method for the accurate and precise determination of equilibrium humidities with a number of interesting future applications

  4. Effect of humidity on radon exhalation rate from concrete

    International Nuclear Information System (INIS)

    Yamanishi, Hirokuni; Obayashi, Haruo; Tsuji, Naruhito; Nakayoshi, Hisao

    1998-01-01

    The objective of the present study is evaluation of seasonal humidity effect on radon exhalation rate from concrete. Three concrete pieces have been placed in three different fixed humidity circumstances for about a year. The three fixed humidities are selected 3, 10, 25 g m -3 in absolute humidity, those correspond to dry condition as control, winter and summer, respectively. Radon exhalation rate from each concrete piece is measured every one month during humidity exposure. Under the lower humidity, radon exhalation rate from concrete is small. On the contrary, radon exhalation rate is large in the higher humidity circumstance. This trend is consistent with the seasonal variation of indoor air radon concentration in low air-exchange-rate room. (author)

  5. Reversible adhesion switching of porous fibrillar adhesive pads by humidity.

    Science.gov (United States)

    Xue, Longjian; Kovalev, Alexander; Dening, Kirstin; Eichler-Volf, Anna; Eickmeier, Henning; Haase, Markus; Enke, Dirk; Steinhart, Martin; Gorb, Stanislav N

    2013-01-01

    We report reversible adhesion switching on porous fibrillar polystyrene-block-poly(2-vinyl pyridine) (PS-b-P2VP) adhesive pads by humidity changes. Adhesion at a relative humidity of 90% was more than nine times higher than at a relative humidity of 2%. On nonporous fibrillar adhesive pads of the same material, adhesion increased only by a factor of ~3.3. The switching performance remained unchanged in at least 10 successive high/low humidity cycles. Main origin of enhanced adhesion at high humidity is the humidity-induced decrease in the elastic modulus of the polar component P2VP rather than capillary force. The presence of spongelike continuous internal pore systems with walls consisting of P2VP significantly leveraged this effect. Fibrillar adhesive pads on which adhesion is switchable by humidity changes may be used for preconcentration of airborne particulates, pollutants, and germs combined with triggered surface cleaning.

  6. The Use of Ambient Humidity Conditions to Improve Influenza Forecast

    Science.gov (United States)

    Shaman, J. L.; Kandula, S.; Yang, W.; Karspeck, A. R.

    2017-12-01

    Laboratory and epidemiological evidence indicate that ambient humidity modulates the survival and transmission of influenza. Here we explore whether the inclusion of humidity forcing in mathematical models describing influenza transmission improves the accuracy of forecasts generated with those models. We generate retrospective forecasts for 95 cities over 10 seasons in the United States and assess both forecast accuracy and error. Overall, we find that humidity forcing improves forecast performance and that forecasts generated using daily climatological humidity forcing generally outperform forecasts that utilize daily observed humidity forcing. These findings hold for predictions of outbreak peak intensity, peak timing, and incidence over 2- and 4-week horizons. The results indicate that use of climatological humidity forcing is warranted for current operational influenza forecast and provide further evidence that humidity modulates rates of influenza transmission.

  7. Noise performance of microwave humidity sounders over their lifetime

    Directory of Open Access Journals (Sweden)

    I. Hans

    2017-12-01

    Full Text Available The microwave humidity sounders Special Sensor Microwave Water Vapor Profiler (SSMT-2, Advanced Microwave Sounding Unit-B (AMSU-B and Microwave Humidity Sounder (MHS to date have been providing data records for 25 years. So far, the data records lack uncertainty information essential for constructing consistent long time data series. In this study, we assess the quality of the recorded data with respect to the uncertainty caused by noise. We calculate the noise on the raw calibration counts from the deep space views (DSVs of the instrument and the noise equivalent differential temperature (NEΔT as a measure for the radiometer sensitivity. For this purpose, we use the Allan deviation that is not biased from an underlying varying mean of the data and that has been suggested only recently for application in atmospheric remote sensing. Moreover, we use the bias function related to the Allan deviation to infer the underlying spectrum of the noise. As examples, we investigate the noise spectrum in flight for some instruments. For the assessment of the noise evolution in time, we provide a descriptive and graphical overview of the calculated NEΔT over the life span of each instrument and channel. This overview can serve as an easily accessible information for users interested in the noise performance of a specific instrument, channel and time. Within the time evolution of the noise, we identify periods of instrumental degradation, which manifest themselves in an increasing NEΔT, and periods of erratic behaviour, which show sudden increases of NEΔT interrupting the overall smooth evolution of the noise. From this assessment and subsequent exclusion of the aforementioned periods, we present a chart showing available data records with NEΔT  <  1 K. Due to overlapping life spans of the instruments, these reduced data records still cover without gaps the time since 1994 and may therefore serve as a first step for constructing long time

  8. Sensitivity of honeybee hygroreceptors to slow humidity changes and temporal humidity variation detected in high resolution by mobile measurements.

    Science.gov (United States)

    Tichy, Harald; Kallina, Wolfgang

    2014-01-01

    The moist cell and the dry cell on the antenna of the male honeybee were exposed to humidities slowly rising and falling at rates between -1.5%/s and +1.5%/s and at varying amplitudes in the 10 to 90% humidity range. The two cells respond to these slow humidity oscillations with oscillations in impulse frequency which depend not only on instantaneous humidity but also on the rate with which humidity changes. The impulse frequency of each cell was plotted as a function of these two parameters and regression planes were fitted to the data points of single oscillation periods. The regression slopes, which estimate sensitivity, rose with the amplitude of humidity oscillations. During large-amplitude oscillations, moist and dry cell sensitivity for instantaneous humidity and its rate of change was high. During small-amplitude oscillations, their sensitivity for both parameters was low, less exactly reflecting humidity fluctuations. Nothing is known about the spatial and temporal humidity variations a honeybee may encounter when flying through natural environments. Microclimatic parameters (absolute humidity, temperature, wind speed) were measured from an automobile traveling through different landscapes of Lower Austria. Landscape type affected extremes and mean values of humidity. Differences between peaks and troughs of humidity fluctuations were generally smaller in open grassy fields or deciduous forests than in edge habitats or forest openings. Overall, fluctuation amplitudes were small. In this part of the stimulus range, hygroreceptor sensitivity is not optimal for encoding instantaneous humidity and the rate of humidity change. It seems that honeybee's hygroreceptors are specialized for detecting large-amplitude fluctuations that are relevant for a specific behavior, namely, maintaining a sufficiently stable state of water balance. The results suggest that optimal sensitivity of both hygroreceptors is shaped not only by humidity oscillation amplitudes but also

  9. Climate Change Adaptation

    DEFF Research Database (Denmark)

    Hudecz, Adriána

    The European Union ROADEX Project 1998 – 2012 was a trans-national roads co-operation aimed at developing ways for interactive and innovative management of low traffic volume roads throughout the cold climate regions of the Northern Periphery Area of Europe. Its goals were to facilitate co......-operation and research into the common problems of the Northern Periphery. This report is an output of the ROADEX “Implementing Accessibility” project (2009-2012). It gives a summary of the results of research into adaptation measures to combat climate change effects on low volume roads in the Northern Periphery...... causes changes in other climatic variables such as rainfall, humidity and wind speed that impact on the functioning of infrastructure such road networks. This paper discusses the climate changes predicted by the world’s meteorological organisations and considers how these may impact on the public...

  10. Effects of ambient air temperature, humidity and rainfall on annual survival of adult little penguins Eudyptula minor in southeastern Australia

    Science.gov (United States)

    Ganendran, L. B.; Sidhu, L. A.; Catchpole, E. A.; Chambers, L. E.; Dann, P.

    2016-08-01

    Seabirds are subject to the influences of local climate variables during periods of land-based activities such as breeding and, for some species, moult; particularly if they undergo a catastrophic moult (complete simultaneous moult) as do penguins. We investigated potential relationships between adult penguin survival and land-based climate variables (ambient air temperature, humidity and rainfall) using 46 years of mark-recapture data of little penguins Eudyptula minor gathered at a breeding colony on Phillip Island in southeastern Australia. Our results showed that adult penguin survival had a stronger association with land-based climate variables during the moult period, when birds were unable to go to sea for up to 3 weeks, than during the breeding period, when birds could sacrifice breeding success in favour of survival. Annual adult survival probability was positively associated with humidity during moult and negatively associated with rainfall during moult. Prolonged heat during breeding and moult had a negative association with annual adult survival. Local climate projections suggest increasing days of high temperatures, fewer days of rainfall which will result in more droughts (and by implication, lower humidity) and more extreme rainfall events. All of these predicted climate changes are expected to have a negative impact on adult penguin survival.

  11. A review on Holocene climate changes in Indian subcontinent

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.

    and terrestrial records document that the climate started shifting from humid to dry arid from 5 ka and reached an arid phase at 3.5 ka. In other tropics of the world also onset of arid climate was documented during the same period. The onset of arid climate at 3...

  12. Influence of cover crop treatments on the performance of a vineyard in a humid region

    Energy Technology Data Exchange (ETDEWEB)

    Trigo-Córdoba, E.; Bouzas-Cid, Y.; Orriols-Fernández, I.; Díaz-Losada, E.; Mirás-Avalos, J.M.

    2015-07-01

    Vineyards are usually managed by tilling the inter-rows to avoid competition from other plants for soil water and nutrients. However, in humid and sub-humid climates, such as that of NW Spain, cover crops may be an advantage for controlling vine vegetative growth and improving berry composition, while reducing management costs. The current study was conducted over three consecutive growing seasons (2012-2014) to assess the effects of establishing three permanent cover crop treatments on water relations, vine physiology, yield and berry composition of a vineyard of the red cultivar ‘Mencía’ (Vitis vinifera L.) located in Leiro, Ourense. Treatments consisted of four different soil management systems: ST, soil tillage; NV, native vegetation; ER, English ryegrass (Lolium perenne L.); and SC, subterranean clover (Trifolium subterraneum L.). Midday stem water potential was more negative in the native vegetation treatment, causing significant reductions in leaf stomatal conductance on certain dates. Total vine leaf area and pruning weight was reduced in the cover crop treatments in the last year of the experiment. Yield was unaffected by the presence of a cover crop. No significant differences among treatments were observed for berry composition; however, wines were positively affected by the SC treatment (higher tannin content and colour intensity and lower malic acid concentration when compared with ST). Wines from the cover crop treatments were preferred by taste panelists. These results indicate that in humid climates cover crop treatments can be useful for reducing vine vegetative growth without compromising yield and berry quality. (Author)

  13. High relative humidity pre-harvest reduces post-harvest proliferation of Salmonella in tomatoes.

    Science.gov (United States)

    Devleesschauwer, Brecht; Marvasi, Massimiliano; Giurcanu, Mihai C; Hochmuth, George J; Speybroeck, Niko; Havelaar, Arie H; Teplitski, Max

    2017-09-01

    Outbreaks of human illness caused by enteric pathogens such as Salmonella are increasingly linked to the consumption of fruits and vegetables. Knowledge on the factors affecting Salmonella proliferation on fresh produce therefore becomes increasingly important to safeguard public health. Previous experiments showed a limited impact of pre-harvest production practices on Salmonella proliferation on tomatoes, but suggested a significant effect of harvest time. We explored the data from two previously published and one unpublished experiment using regression trees, which allowed overcoming the interpretational difficulties of classical statistical models with higher order interactions. We assessed the effect of harvest time by explicitly modeling the climatic conditions at harvest time and by performing confirmatory laboratory experiments. Across all datasets, regression trees confirmed the dominant effect of harvest time on Salmonella proliferation, with humidity-related factors emerging as the most important underlying climatic factors. High relative humidity the week prior to harvest was consistently associated with lower Salmonella proliferation. A controlled lab experiment confirmed that tomatoes containing their native epimicrobiota supported significantly lower Salmonella proliferation when incubated at higher humidity prior to inoculation. The complex interactions between environmental conditions and the native microbiota of the tomato crop remain to be fully understood. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Medical Meteorology: the Relationship between Meteorological Parameters (Humidity, Rainfall, Wind, and Temperature and Brucellosis in Zanjan Province

    Directory of Open Access Journals (Sweden)

    Yousefali Abedini

    2016-06-01

    Full Text Available Background: Brucellosis (Malta fever is a major contagious zoonotic disease, with economic and public health importance. Methods To assess the effect of meteorological (temperature, rainfall, humidity, and wind and climate parameters on incidence of brucellosis, brucellosis distribution and meteorological zoning maps of Zanjan Province were prepared using Inverse Distance Weighting (IDW and Kriging technique in Arc GIS medium. Zoning maps of mean temperature, rainfall, humidity, and wind were compared to brucellosis distribution maps. Results: Correlation test showed no relationship between the mean number of patients with brucellosis and any of the four meteorological parameters. Conclusion: It seems that in Zanjan province there is no correlation between brucellosis and meteorological parameters.

  15. Humidity Testing for Human Rated Spacecraft

    Science.gov (United States)

    Johnson, Gary B.

    2009-01-01

    Determination that equipment can operate in and survive exposure to the humidity environments unique to human rated spacecraft presents widely varying challenges. Equipment may need to operate in habitable volumes where the atmosphere contains perspiration, exhalation, and residual moisture. Equipment located outside the pressurized volumes may be exposed to repetitive diurnal cycles that may result in moisture absorption and/or condensation. Equipment may be thermally affected by conduction to coldplate or structure, by forced or ambient air convection (hot/cold or wet/dry), or by radiation to space through windows or hatches. The equipment s on/off state also contributes to the equipment s susceptibility to humidity. Like-equipment is sometimes used in more than one location and under varying operational modes. Due to these challenges, developing a test scenario that bounds all physical, environmental and operational modes for both pressurized and unpressurized volumes requires an integrated assessment to determine the "worst-case combined conditions." Such an assessment was performed for the Constellation program, considering all of the aforementioned variables; and a test profile was developed based on approximately 300 variable combinations. The test profile has been vetted by several subject matter experts and partially validated by testing. Final testing to determine the efficacy of the test profile on actual space hardware is in the planning stages. When validation is completed, the test profile will be formally incorporated into NASA document CxP 30036, "Constellation Environmental Qualification and Acceptance Testing Requirements (CEQATR)."

  16. The ecosystem of the Mid-Atlantic Ridge at the sub-polar front and Charlie-Gibbs Fracture Zone; ECO-MAR project strategy and description of the sampling programme 2007-2010

    Science.gov (United States)

    Priede, Imants G.; Billett, David S. M.; Brierley, Andrew S.; Hoelzel, A. Rus; Inall, Mark; Miller, Peter I.; Cousins, Nicola J.; Shields, Mark A.; Fujii, Toyonobu

    2013-12-01

    The ECOMAR project investigated photosynthetically-supported life on the North Mid-Atlantic Ridge (MAR) between the Azores and Iceland focussing on the Charlie-Gibbs Fracture Zone area in the vicinity of the sub-polar front where the North Atlantic Current crosses the MAR. Repeat visits were made to four stations at 2500 m depth on the flanks of the MAR in the years 2007-2010; a pair of northern stations at 54°N in cold water north of the sub-polar front and southern stations at 49°N in warmer water influenced by eddies from the North Atlantic Current. At each station an instrumented mooring was deployed with current meters and sediment traps (100 and 1000 m above the sea floor) to sample downward flux of particulate matter. The patterns of water flow, fronts, primary production and export flux in the region were studied by a combination of remote sensing and in situ measurements. Sonar, tow nets and profilers sampled pelagic fauna over the MAR. Swath bathymetry surveys across the ridge revealed sediment-covered flat terraces parallel to the axis of the MAR with intervening steep rocky slopes. Otter trawls, megacores, baited traps and a suite of tools carried by the R.O.V. Isis including push cores, grabs and a suction device collected benthic fauna. Video and photo surveys were also conducted using the SHRIMP towed vehicle and the R.O.V. Isis. Additional surveying and sampling by landers and R.O.V. focussed on the summit of a seamount (48°44‧N, 28°10‧W) on the western crest of the MAR between the two southern stations.

  17. THE INFLUENCE OF VARIABLE TEMPERATURE AND HUMIDITY ON THE PREDATION EFFICIENCY OF P. PERSIMILIS, N. CALIFORNICUS AND N. FALLACIS.

    Science.gov (United States)

    Audenaert, J; Vangansbeke, D; Verhoeven, R; De Clercq, P; Tirry, L; Gobin, B

    2014-01-01

    Predatory mites like Phytoseiulus persimilis Athias-Henriot, Neoseiulus californicus McGregor and N. fallacis (Garman) (Acari: Phytoseiidae) are essential in sustainable control strategies of the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) in warm greenhouse cultures to complement imited available pesticides and to tackle emerging resistance. However, in response to high energy prices, greenhouse plant breeders have recently changed their greenhouse steering strategies, allowing more variation in temperature and humidity. The impact of these variations on biological control agents is poorly understood. Therefore, we constructed functional response models to demonstrate the impact of realistic climate variations on predation efficiency. First, two temperature regimes were compared at constant humidity (70%) and photoperiod (16L:8D): DIF0 (constant temperature) and DIF15 (variable temperature with day-night difference of 15°C). At mean temperatures of 25°C, DIF15 had a negative influence on the predation efficiency of P. persimilis and N. californicus, as compared to DIF0. At low mean temperatures of 15°C, however, DIF15 showed a higher predation efficiency for P. persimilis and N. californicus. For N. fallacis no difference was observed at both 15°C and 25°C. Secondly, two humidity regimes were compared, at a mean temperature of 25°C (DIFO) and constant photoperiod (16L:8D): RHCTE (constant 70% humidity) and RHALT (alternating 40% L:70%D humidity). For P. persimilis and N. fallacis RHCTE resulted in a higher predation efficiency than RHALT, for N. californicus this effect was opposite. This shows that N. californicus is more adapted to dry climates as compared to the other predatory mites. We conclude that variable greenhouse climates clearly affect predation efficiency of P. persimilis, N. californicus and N. fallacis. To obtain optimal control efficiency, the choice of predatory mites (including dose and application frequency

  18. The dairy cow and global climate changes

    OpenAIRE

    Flávio Baccari Jr

    2015-01-01

     High producing dairy cows are more sensitive to heat stress due mainly to their higher resting metabolic rate as compared to low producing and dry cows. Their responses to increasing levels of the temperature-humidity and the black globe-humidity indices are discussed as well as some aspects of heat tolerance as related to body temperature increase and milk production decrease. Some mitigation and adaptation practices are recommended to face the challenges of global climate changes.

  19. A Trial Intercomparison of Humidity Generators at Extremes of Range Using Relative Humidity Transmitters

    Science.gov (United States)

    Stevens, M.; Benyon, R.; Bell, S. A.; Vicente, T.

    2008-10-01

    In order to effectively implement the Mutual Recognition Arrangement (MRA) of the International Committee for Weights and Measures (CIPM), national metrology institutes (NMIs) are required to support their claims of calibration and measurement capability (CMC) with a quality system compliant with ISO/IEC 17025, and with suitable evidence of participation in key or supplementary comparisons. The CMC review process, both at regional and inter-regional levels, uses criteria that combine the provisions mentioned above, together with additional evidence demonstrating scientific and technical competence of the institutes. For dew-point temperatures, there are key comparisons in progress under the Consultative Committee for Thermometry (CCT) and under the European regional metrology organisation (EUROMET), together with information available on past regional supplementary comparisons. However, for relative humidity there are, to date, no such comparisons available to support CMC entries. This paper presents and discusses the results of a preliminary investigation of the use of relative humidity and temperature transmitters in order to determine their suitability for the intercomparison of standard humidity generators in support of CMC claims for the calibration of relative humidity instruments. The results of a recent bilateral comparison between 2 NMIs at the extremes of the range up to 98%rh at 70 °C, and down to 1%rh at -40 °C are reported. Specific precautions and recommendations on the use of the devices as transfer standards are presented.

  20. INFLUENCE OF TEMPERATURE AND RELATIVE HUMIDITY ON THE STUDDED AGARICUS BLAZEI MURRILL MUSHROOM COMPOST

    Directory of Open Access Journals (Sweden)

    Sándor Rózsa

    2017-12-01

    Full Text Available Almond mushroom, Agaricus blazei Murrill, is the so-called secondary saprophyte, developing on partially processed substrate, in which microorganisms reduced complex ligno-cellulose compounds. Numerous authors have shown that due to the similar life cycle in the cultivation of almond mushroom technologies developed for white button mushroom may be applied. However, almond mushroom requires high temperature and high humidity as well as access to light to form fruiting bodies. In Brazil, due to the advantageous climatic conditions this species is frequently grown outdoors; however, in other countries - mainly due to its high temperature requirements - such cultivation system is risky and may only be successful during very warm summers. In this study, we analyzed four kind of compost studded by Agaricus blazei Murrill mushroom mycelium. We recorded every hour the air and compost temperature and the air relative humidity. The best studded compost was the classical, followed by synthetic and then by the mixt compost.

  1. Within-Crop Air Temperature and Humidity Outcomes on Spatio-Temporal Distribution of the Key Rose Pest Frankliniella occidentalis.

    Science.gov (United States)

    Fatnassi, Hicham; Pizzol, Jeannine; Senoussi, Rachid; Biondi, Antonio; Desneux, Nicolas; Poncet, Christine; Boulard, Thierry

    2015-01-01

    Frankliniella occidentalis (Pergande) is a key pest of various crops worldwide. In this study, we analyse the dependence of the infestation of this pest on spatially distributed micro climatic factors in a rose greenhouse. Despite the importance of this subject, the few existing studies have been realized in laboratory rather than in greenhouse conditions. However, recent progress on greenhouse microclimate characterisation has highlighted the strong indoor climate heterogeneity that may influence the within-crop pest distribution. In this study, both microclimate (air temperature and humidity) and thrips distribution were simultaneously mapped in a rose greenhouse. The measurements were sensed in a horizontal plane situated at mid-height of the rose crop inside the greenhouse. Simultaneously, thrips population dynamics were assessed after an artificial and homogeneous infestation of the rose crop. The spatio-temporal distribution of climate and thrips within the greenhouse were compared, and links between thrips infestation and climatic conditions were investigated. A statistical model was used to define the favourable climate conditions for thrips adults and larvae. Our results showed that (i) the air temperature and air humidity were very heterogeneously distributed within the crop, (ii) pest populations aggregated in the most favourable climatic areas and (iii) the highest population density of thrips adults and larvae were recorded at 27°C and 22°C for temperature and 63% and 86% for humidity, respectively. These findings confirm, in real rose cropping conditions, previous laboratory studies on the F. occidentalis climatic optimum and provide a solid scientific support for climatic-based control methods against this pest.

  2. Within-Crop Air Temperature and Humidity Outcomes on Spatio-Temporal Distribution of the Key Rose Pest Frankliniella occidentalis.

    Directory of Open Access Journals (Sweden)

    Hicham Fatnassi

    Full Text Available Frankliniella occidentalis (Pergande is a key pest of various crops worldwide. In this study, we analyse the dependence of the infestation of this pest on spatially distributed micro climatic factors in a rose greenhouse. Despite the importance of this subject, the few existing studies have been realized in laboratory rather than in greenhouse conditions. However, recent progress on greenhouse microclimate characterisation has highlighted the strong indoor climate heterogeneity that may influence the within-crop pest distribution. In this study, both microclimate (air temperature and humidity and thrips distribution were simultaneously mapped in a rose greenhouse. The measurements were sensed in a horizontal plane situated at mid-height of the rose crop inside the greenhouse. Simultaneously, thrips population dynamics were assessed after an artificial and homogeneous infestation of the rose crop. The spatio-temporal distribution of climate and thrips within the greenhouse were compared, and links between thrips infestation and climatic conditions were investigated. A statistical model was used to define the favourable climate conditions for thrips adults and larvae. Our results showed that (i the air temperature and air humidity were very heterogeneously distributed within the crop, (ii pest populations aggregated in the most favourable climatic areas and (iii the highest population density of thrips adults and larvae were recorded at 27°C and 22°C for temperature and 63% and 86% for humidity, respectively. These findings confirm, in real rose cropping conditions, previous laboratory studies on the F. occidentalis climatic optimum and provide a solid scientific support for climatic-based control methods against this pest.

  3. Diurnal variations of humidity and ice water content in the tropical upper troposphere

    Directory of Open Access Journals (Sweden)

    P. Eriksson

    2010-12-01

    Full Text Available Observational results of diurnal variations of humidity from Odin-SMR and AURA-MLS, and cloud ice mass from Odin-SMR and CloudSat are presented for the first time. Comparisons show that the retrievals of humidity and cloud ice from these two satellite combinations are in good agreement. The retrieved data are combined from four almost evenly distributed times of the day allowing mean values, amplitudes and phases of the diurnal variations around 200 hpa to be estimated. This analysis is applied to six climatologically distinct regions, five located in the tropics and one over the subtropical northern Pacific Ocean. The strongest diurnal cycles are found over tropical land regions, where the amplitude is ~7 RHi for humidity and ~50% for ice mass. The greatest ice mass for these regions is found during the afternoon, and the humidity maximum is observed to lag this peak by ~6 h. Over tropical ocean regions the variations are smaller and the maxima in both ice mass and humidity are found during the early morning. Observed results are compared with output from three climate models (ECHAM, EC-EARTH and CAM3. Direct measurement-model comparisons were not possible because the measured and modelled cloud ice masses represent different quantities. To make a meaningful comparison, the amount of snow had to be estimated from diagnostic parameters of the models. There is a high probability that the models underestimate the average ice mass (outside the 1-σ uncertainty. The models also show clear deficiencies when it comes to amplitude and phase of the regional variations, but to varying degrees.

  4. Effects of ambient temperature, humidity, and other meteorological variables on hospital admissions for angina pectoris.

    Science.gov (United States)

    Abrignani, Maurizio G; Corrao, Salvatore; Biondo, Giovan B; Lombardo, Renzo M; Di Girolamo, Paola; Braschi, Annabella; Di Girolamo, Alberto; Novo, Salvatore

    2012-06-01

    Seasonal peaks in cardiovascular disease incidence have been widely reported, suggesting weather has a role. The aim of our study was to determine the influence of climatic variables on angina pectoris hospital admissions. We correlated the daily number of angina cases admitted to a western Sicilian hospital over a period of 12 years and local weather conditions (temperature, humidity, wind force and direction, precipitation, sunny hours and atmospheric pressure) on a day-to-day basis. A total of 2459 consecutive patients were admitted over the period 1987-1998 (1562 men, 867 women; M/F - 1:8). A seasonal variation was found with a noticeable winter peak. The results of Multivariate Poisson analysis showed a significant association between the daily number of angina hospital admission, temperature, and humidity. Significant incidence relative ratios (95% confidence intervals/measure unit) were, in males, 0.988 (0.980-0.996) (p = 0.004) for minimal temperature, 0.990 (0.984-0.996) (p = 0.001) for maximal humidity, and 1.002 (1.000-1.004) (p = 0.045) for minimal humidity. The corresponding values in females were 0.973 (0.951-0.995) (p < 0.017) for maximal temperature and 1.024 (1.001-1.048) (p = 0.037) for minimal temperature. Environmental temperature and humidity may play an important role in the pathogenesis of angina, although it seems different according to the gender. These data may help to understand the mechanisms that trigger ischemic events and to better organize hospital assistance throughout the year.

  5. The use of ambient humidity conditions to improve influenza forecast.

    Directory of Open Access Journals (Sweden)

    Jeffrey Shaman

    2017-11-01

    Full Text Available Laboratory and epidemiological evidence indicate that ambient humidity modulates the survival and transmission of influenza. Here we explore whether the inclusion of humidity forcing in mathematical models describing influenza transmission improves the accuracy of forecasts generated with those models. We generate retrospective forecasts for 95 cities over 10 seasons in the United States and assess both forecast accuracy and error. Overall, we find that humidity forcing improves forecast performance (at 1-4 lead weeks, 3.8% more peak week and 4.4% more peak intensity forecasts are accurate than with no forcing and that forecasts generated using daily climatological humidity forcing generally outperform forecasts that utilize daily observed humidity forcing (4.4% and 2.6% respectively. These findings hold for predictions of outbreak peak intensity, peak timing, and incidence over 2- and 4-week horizons. The results indicate that use of climatological humidity forcing is warranted for current operational influenza forecast.

  6. The sensitivity to humidity of radon monitoring instruments

    International Nuclear Information System (INIS)

    Schmied, H.

    1984-01-01

    In a project funded by the Swedish Building Research Council (BFR) a continuous radon monitoring instrument (RGA-400 EDA Instr. Inc.) with electrostatic field collection has been calibrated. The original calibration factor gave no reliable radon readings and was therefore corrected for relative humidity by EDA. From four calibrations in the radon chamber at the Swedish Radiation Protection Board (SSI) it was clear that the instrument was sensitive to absolute humidity, which gave better agreement than relative humidity or temperature. Sensitivity to humidity for this principle of measure ment has been presented in various papers without presenting any combined influence with temperature, which can lead to the wrong conclusions, especially when the temperature levels differ. Some laboratories use humidity absorbants to overcome this humidity dependence. In this paper the calibration results for the FGA-400 radon readings only, are presented. (Author)

  7. Temperature, humidity and time. Combined effects on radiochromic film dosimeters

    DEFF Research Database (Denmark)

    Abdel-Fattah, A.A.; Miller, A.

    1996-01-01

    The effects of both relative humidity and temperature during irradiation on the dose response of FWT-60-00 and Riso B3 radiochromic film dosimeters have been investigated in the relative humidity (RH) range 11-94% and temperature range 20-60 degrees C for irradiation by Co-60 photons and 10-Me......V electrons. The results show that humidity and temperature cannot be treated as independent variables, rather there appears to be interdependence between absorbed dose, temperature, and humidity. Dose rate does not seem to play a significant role. The dependence of temperature during irradiation is +0.......25 +/- 0.1% per degrees C for the FWT-60-00 dosimeters and +0.5 +/- 0.1% per degrees C For Riso B3 dosimeters at temperatures between 20 and 50 degrees C and at relative humidities between 20 and 53%. At extreme conditions both with respect to temperature and to humidity, the dosimeters show much stronger...

  8. A CMOS Humidity Sensor for Passive RFID Sensing Applications

    Science.gov (United States)

    Deng, Fangming; He, Yigang; Zhang, Chaolong; Feng, Wei

    2014-01-01

    This paper presents a low-cost low-power CMOS humidity sensor for passive RFID sensing applications. The humidity sensing element is implemented in standard CMOS technology without any further post-processing, which results in low fabrication costs. The interface of this humidity sensor employs a PLL-based architecture transferring sensor signal processing from the voltage domain to the frequency domain. Therefore this architecture allows the use of a fully digital circuit, which can operate on ultra-low supply voltage and thus achieves low-power consumption. The proposed humidity sensor has been fabricated in the TSMC 0.18 μm CMOS process. The measurements show this humidity sensor exhibits excellent linearity and stability within the relative humidity range. The sensor interface circuit consumes only 1.05 μW at 0.5 V supply voltage and reduces it at least by an order of magnitude compared to previous designs. PMID:24841250

  9. Effect of relative humidity on growth of sodium oxide aerosols

    International Nuclear Information System (INIS)

    Sundarajan, A.R.; Mitragotri, D.S.; Mukunda Rao, S.R.

    1982-01-01

    Behavior of aerosol resulting from sodium fires in a closed vessel is investigated and the changes in the particle size distribution of the aerosol due to coagulation and humidity have been studied. The initial mass concentration is in the range of 80 -- 500 mg/m 3 and the relative humidity is varied between 50 to 98%. The initial size of the released aerosol is found to be 0.9 μm. Equilibrium diameters of particles growing in humid air have been computed for various humidity levels using water activity of sodium hydroxide. Both theoretical and experimental results have yielded growth ratios of about 3 at about 95% relative humidity. It is recommended that the computer codes dealing with aerosol coagulation behavior in reactor containment should include an appropriate humidity-growth function. (author)

  10. A CMOS Humidity Sensor for Passive RFID Sensing Applications

    Directory of Open Access Journals (Sweden)

    Fangming Deng

    2014-05-01

    Full Text Available This paper presents a low-cost low-power CMOS humidity sensor for passive RFID sensing applications. The humidity sensing element is implemented in standard CMOS technology without any further post-processing, which results in low fabrication costs. The interface of this humidity sensor employs a PLL-based architecture transferring sensor signal processing from the voltage domain to the frequency domain. Therefore this architecture allows the use of a fully digital circuit, which can operate on ultra-low supply voltage and thus achieves low-power consumption. The proposed humidity sensor has been fabricated in the TSMC 0.18 μm CMOS process. The measurements show this humidity sensor exhibits excellent linearity and stability within the relative humidity range. The sensor interface circuit consumes only 1.05 µW at 0.5 V supply voltage and reduces it at least by an order of magnitude compared to previous designs.

  11. A CMOS humidity sensor for passive RFID sensing applications.

    Science.gov (United States)

    Deng, Fangming; He, Yigang; Zhang, Chaolong; Feng, Wei

    2014-05-16

    This paper presents a low-cost low-power CMOS humidity sensor for passive RFID sensing applications. The humidity sensing element is implemented in standard CMOS technology without any further post-processing, which results in low fabrication costs. The interface of this humidity sensor employs a PLL-based architecture transferring sensor signal processing from the voltage domain to the frequency domain. Therefore this architecture allows the use of a fully digital circuit, which can operate on ultra-low supply voltage and thus achieves low-power consumption. The proposed humidity sensor has been fabricated in the TSMC 0.18 μm CMOS process. The measurements show this humidity sensor exhibits excellent linearity and stability within the relative humidity range. The sensor interface circuit consumes only 1.05 µW at 0.5 V supply voltage and reduces it at least by an order of magnitude compared to previous designs.

  12. The use of ambient humidity conditions to improve influenza forecast.

    Science.gov (United States)

    Shaman, Jeffrey; Kandula, Sasikiran; Yang, Wan; Karspeck, Alicia

    2017-11-01

    Laboratory and epidemiological evidence indicate that ambient humidity modulates the survival and transmission of influenza. Here we explore whether the inclusion of humidity forcing in mathematical models describing influenza transmission improves the accuracy of forecasts generated with those models. We generate retrospective forecasts for 95 cities over 10 seasons in the United States and assess both forecast accuracy and error. Overall, we find that humidity forcing improves forecast performance (at 1-4 lead weeks, 3.8% more peak week and 4.4% more peak intensity forecasts are accurate than with no forcing) and that forecasts generated using daily climatological humidity forcing generally outperform forecasts that utilize daily observed humidity forcing (4.4% and 2.6% respectively). These findings hold for predictions of outbreak peak intensity, peak timing, and incidence over 2- and 4-week horizons. The results indicate that use of climatological humidity forcing is warranted for current operational influenza forecast.

  13. Porous ZrO_2-TiO_2 ceramics for applications as sensing elements in the air humidity monitoring

    International Nuclear Information System (INIS)

    Oliveira, Rodrigo de Matos; Nono, Maria do Carmo de Andrade

    2011-01-01

    The environmental monitoring requires versatile, reliable and lower cost instruments. The chemical superficial absorption/adsorption capability of water molecules by several ceramic oxides makes them excellent candidates for this application. In this way, many efforts have been made for the development of porous ceramics, manufactured from mechanical mixture of ZrO_2 and TiO_2 powders, for application as air humidity sensing elements. The sintered ceramics were characterized as for crystalline phases (X-ray diffraction) and pores structure (scanning electron microscopy and mercury porosimetry). The relative humidity curves for the ceramics were obtained from measurements with RLC bridge in climatic chamber. The behavior of these curves were comparatively analyzed with the aid of pores sizes distribution curves, obtained through mercury porosimetry. The results evidenced that the air humidity ceramic sensing elements are very promising ones. (author)

  14. Temperature and Humidity Control in Air-Conditioned Buildings with lower Energy Demand and increased Indoor Air Quality

    DEFF Research Database (Denmark)

    Paul, Joachim; Martos, E. T.

    2003-01-01

    Air-conditioning is not only a matter of temperature control. Thermal comfort and good indoor air quality are mainly a matter of humidity. Human health and well being may suffer seriously from inadequate humidity and/or too low temperatures in a room. A case study involving supermarket air......%. For indoor air temperature and humidity control, the use of an ice slurry (´Binary Ice´)was compared to conventional chilled water. The use of Binary Ice instead of chilled water makes the air handling and air distribution installation much simpler, recirculation of air becomes obsolete, and a higher portion...... of ambient air can be supplied, thus improving the indoor air quality still further. Reheating of air is not necessary when using Binary Ice. The introduction of chilled air into a room requires a different type of air outlet, however. When using Binary Ice, energy savings are high for climates with low...

  15. Photoelectron spectroscopy of surfaces under humid conditions

    International Nuclear Information System (INIS)

    Bluhm, Hendrik

    2010-01-01

    The interaction of water with surfaces plays a major role in many processes in the environment, atmosphere and technology. Weathering of rocks, adhesion between surfaces, and ionic conductance along surfaces are among many phenomena that are governed by the adsorption of molecularly thin water layers under ambient humidities. The properties of these thin water films, in particular their thickness, structure and hydrogen-bonding to the substrate as well as within the water film are up to now not very well understood. Ambient pressure photoelectron spectroscopy (APXPS) is a promising technique for the investigation of the properties of thin water films. In this article we will discuss the basics of APXPS as well as the particular challenges that are posed by investigations in water vapor at Torr pressures. We will also show examples of the application of APXPS to the study of water films on metals and oxides.

  16. Mask humidity during CPAP: influence of ambient temperature, heated humidification and heated tubing

    Directory of Open Access Journals (Sweden)

    Nilius G

    2018-05-01

    Full Text Available Georg Nilius,1,2 Ulrike Domanski,1 Maik Schroeder,1 Holger Woehrle,3,4 Andrea Graml,4 Karl-Josef Franke,1,2 1Helios Klinik Hagen-Ambrock, Department of Pneumology, Hagen, Germany; 2Department of Internal Medicine, Witten-Herdecke University, Witten, Germany; 3Sleep and Ventilation Center Blaubeuren, Respiratory Center Ulm, Ulm, Germany; 4ResMed Science Center, ResMed Germany, Martinsried, Germany Purpose: Mucosal drying during continuous positive airway pressure (CPAP therapy is problematic for many patients. This study assessed the influence of ambient relative humidity (rH and air temperature (T in winter and summer on mask humidity during CPAP, with and without mask leak, and with or without heated humidification ± heated tubing. Methods: CPAP (8 and 12 cmH2O without humidification (no humidity [nH], with heated humidification controlled by ambient temperature and humidity (heated humidity [HH] and HH plus heated tubing climate line (CL, with and without leakage, were compared in 18 subjects with OSA during summer and winter. Results: The absolute humidity (aH and the T inside the mask during CPAP were significantly lower in winter versus summer under all applied conditions. Overall, absolute humidity differences between summer and winter were statistically significant in both HH and CL vs. nH (p < 0.05 in the presence and absence of mouth leak. There were no significant differences in aH between HH and CL. However, in-mask temperature during CL was higher (p < 0.05 and rH lower than during HH. In winter, CPAP with CL was more likely to keep rH constant at 80% than CPAP without humidification or with standard HH. Conclusion: Clinically-relevant reductions in aH were documented during CPAP given under winter conditions. The addition of heated humidification, using a heated tube to avoid condensation is recommended to increase aH, which could be useful in CPAP users complaining of nose and throat symptoms. Keywords: continuous positive

  17. Thermal Comfort and Optimum Humidity Part 1

    Directory of Open Access Journals (Sweden)

    M. V. Jokl

    2002-01-01

    Full Text Available The hydrothermal microclimate is the main component in indoor comfort. The optimum hydrothermal level can be ensured by suitable changes in the sources of heat and water vapor within the building, changes in the environment (the interior of the building and in the people exposed to the conditions inside the building. A change in the heat source and the source of water vapor involves improving the heat - insulating properties and the air permeability of the peripheral walls and especially of the windows. The change in the environment will bring human bodies into balance with the environment. This can be expressed in terms of an optimum or at least an acceptable globe temperature, an adequate proportion of radiant heat within the total amount of heat from the environment (defined by the difference between air and wall temperature, uniform cooling of the human body by the environment, defined a by the acceptable temperature difference between head and ankles, b by acceptable temperature variations during a shift (location unchanged, or during movement from one location to another without a change of clothing. Finally, a moisture balance between man and the environment is necessary (defined by acceptable relative air humidity. A change for human beings means a change of clothes which, of course, is limited by social acceptance in summer and by inconvenient heaviness in winter. The principles of optimum heating and cooling, humidification and dehumidification are presented in this paper.Hydrothermal comfort in an environment depends on heat and humidity flows (heat and water vapors, occurring in a given space in a building interior and affecting the total state of the human organism.

  18. Thermal Comfort and Optimum Humidity Part 2

    Directory of Open Access Journals (Sweden)

    M. V. Jokl

    2002-01-01

    Full Text Available The hydrothermal microclimate is the main component in indoor comfort. The optimum hydrothermal level can be ensured by suitable changes in the sources of heat and water vapor within the building, changes in the environment (the interior of the building and in the people exposed to the conditions inside the building. A change in the heat source and the source of water vapor involves improving the heat - insulating properties and the air permeability of the peripheral walls and especially of the windows. The change in the environment will bring human bodies into balance with the environment. This can be expressed in terms of an optimum or at least an acceptable globe temperature, an adequate proportion of radiant heat within the total amount of heat from the environment (defined by the difference between air and wall temperature, uniform cooling of the human body by the environment, defined a by the acceptable temperature difference between head and ankles, b by acceptable temperature variations during a shift (location unchanged, or during movement from one location to another without a change of clothing. Finally, a moisture balance between man and the environment is necessary (defined by acceptable relative air humidity. A change for human beings means a change of clothes which, of course, is limited by social acceptance in summer and by inconvenient heaviness in winter. The principles of optimum heating and cooling, humidification and dehumidification are presented in this paper.Hydrothermal comfort in an environment depends on heat and humidity flows (heat and water vapors, occurring in a given space in a building interior and affecting the total state of the human organism.

  19. Do honeybees, Apis mellifera scutellata, regulate humidity in their nest?

    Science.gov (United States)

    Human, Hannelie; Nicolson, Sue W.; Dietemann, Vincent

    2006-08-01

    Honeybees are highly efficient at regulating the biophysical parameters of their hive according to colony needs. Thermoregulation has been the most extensively studied aspect of nest homeostasis. In contrast, little is known about how humidity is regulated in beehives, if at all. Although high humidity is necessary for brood development, regulation of this parameter by honeybee workers has not yet been demonstrated. In the past, humidity was measured too crudely for a regulation mechanism to be identified. We reassess this issue, using miniaturised data loggers that allow humidity measurements in natural situations and at several places in the nest. We present evidence that workers influence humidity in the hive. However, there are constraints on potential regulation mechanisms because humidity optima may vary in different locations of the nest. Humidity could also depend on variable external factors, such as water availability, which further impair the regulation. Moreover, there are trade-offs with the regulation of temperature and respiratory gas exchanges that can disrupt the establishment of optimal humidity levels. As a result, we argue that workers can only adjust humidity within sub-optimal limits.

  20. Miniature Flexible Humidity Sensitive Patches for Space Suits, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced space suit technologies demand improved, simplified, long-life regenerative sensing technologies, including humidity sensors, that exceed the performance of...

  1. A regional climate model for the Arctic and the North Atlantic; Ein regionales Klimamodell fuer die Arktis und den Nordatlantik

    Energy Technology Data Exchange (ETDEWEB)

    Berndt, H

    2001-07-01

    The Arctic and the subpolar region of the North Atlantic with their complex net of mechanisms and feedbacks play an important role in the climate system. Because of the sparse observations and the low resolution of the global models the high-resolution regional climate model REMO provides an improved tool to investigate arctic processes. REMO is based on the former numerical weather prediction model EM of the German Weather Service (DWD) and was further developed at the Max-Planck-Institute for Meteorology (MPIfM) in Hamburg. It has two different parameterization schemes - the original one called DWD-physics and additionally the ECHAM4-physics from MPIfM. The dynamical scheme is in both cases identical. In a first step REMO is adapted to the new domain. This configuration covers the Arctic and the North Atlantic down to 40 N with a horizontal resolution of 0.5 x 0.5 and 121 x 145 grid points. Different periods are simulated with DWD- and ECHAM4-Physics in forecast - as well as in climate-mode. Lateral boundary conditions are taken from NCEP/NCAR-reanalysis. Comparing REMO with ship observations in the Labrador Sea yields a better correspondence than the reanalysis data. Simulated precipitation is overestimated most probably due to unrealistic high humidity in the NCEP/NCAR-reanalysis. Observed sensible heat fluxes are much lower than the REMO and NCEP/NCAR simulated fluxes. REMO simulations in climate- and forecast-mode with ECHAM4-parameterizations are compared with measured surface temperatures and precipitation distributions. While there are numerically generated spectral spikes in the NCEP/NCAR precipitation fields in the Arctic, they are not found in the REMO results. In a sensitivity study the impact of higher surface roughness in the marginal ice zone is investigated. Ensemble experiments show the high internal variability masking any signals due to the changed roughness length. This high internal variability is mostly due to the large model domain and the

  2. Development of relative humidity models by using optimized neural network structures

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-romero, A.; Ortega, J. F.; Juan, J. A.; Tarjuelo, J. M.; Moreno, M. A.

    2010-07-01

    Climate has always had a very important role in life on earth, as well as human activity and health. The influence of relative humidity (RH) in controlled environments (e.g. industrial processes in agro-food processing, cold storage of foods such as fruits, vegetables and meat, or controls in greenhouses) is very important. Relative humidity is a main factor in agricultural production and crop yield (due to the influence on crop water demand or the development and distribution of pests and diseases, for example). The main objective of this paper is to estimate RH [maximum (RHmax), average (RHave), and minimum (RHmin)] data in a specific area, being applied to the Region of Castilla-La Mancha (C-LM) in this case, from available data at thermo-pluviometric weather stations. In this paper Artificial neural networks (ANN) are used to generate RH considering maximum and minimum temperatures and extraterrestrial solar radiation data. Model validation and generation is based on data from the years 2000 to 2008 from 44 complete agroclimatic weather stations. Relative errors are estimated as 1) spatial errors of 11.30%, 6.80% and 10.27% and 2) temporal errors of 10.34%, 6.59% and 9.77% for RHmin, RHmax and RHave, respectively. The use of ANNs is interesting in generating climate parameters from available climate data. For determining optimal ANN structure in estimating RH values, model calibration and validation is necessary, considering spatial and temporal variability. (Author) 44 refs.

  3. Empirical model for estimating dengue incidence using temperature, rainfall, and relative humidity: a 19-year retrospective analysis in East Delhi.

    Science.gov (United States)

    Ramachandran, Vishnampettai G; Roy, Priyamvada; Das, Shukla; Mogha, Narendra Singh; Bansal, Ajay Kumar

    2016-01-01

    Aedes mosquitoes are responsible for transmitting the dengue virus. The mosquito lifecycle is known to be influenced by temperature, rainfall, and relative humidity. This retrospective study was planned to investigate whether climatic factors could be used to predict the occurrence of dengue in East Delhi. The number of monthly dengue cases reported over 19 years was obtained from the laboratory records of our institution. Monthly data of rainfall, temperature, and humidity collected from a local weather station were correlated with the number of monthly reported dengue cases. One-way analysis of variance was used to analyse whether the climatic parameters differed significantly among seasons. Four models were developed using negative binomial generalized linear model analysis. Monthly rainfall, temperature, humidity, were used as independent variables, and the number of dengue cases reported monthly was used as the dependent variable. The first model considered data from the same month, while the other three models involved incorporating data with a lag phase of 1, 2, and 3 months, respectively. The greatest number of cases was reported during the post-monsoon period each year. Temperature, rainfall, and humidity varied significantly across the pre-monsoon, monsoon, and post-monsoon periods. The best correlation between these three climatic factors and dengue occurrence was at a time lag of 2 months. This study found that temperature, rainfall, and relative humidity significantly affected dengue occurrence in East Delhi. This weather-based dengue empirical model can forecast potential outbreaks 2-month in advance, providing an early warning system for intensifying dengue control measures.

  4. The effects of lithographic residues and humidity on graphene field ...

    Indian Academy of Sciences (India)

    humidity at graphene field effect transistors (GFETs). While the exact means of humidity interacting with hydropho- bic graphene remains unknown, this work examines pristine and lithographic-process-applied graphene surfaces with surface ... temperature quantum Hall effect, linear electron dispersion at the vicinity of the ...

  5. A physically based analytical spatial air temperature and humidity model

    Science.gov (United States)

    Yang Yang; Theodore A. Endreny; David J. Nowak

    2013-01-01

    Spatial variation of urban surface air temperature and humidity influences human thermal comfort, the settling rate of atmospheric pollutants, and plant physiology and growth. Given the lack of observations, we developed a Physically based Analytical Spatial Air Temperature and Humidity (PASATH) model. The PASATH model calculates spatial solar radiation and heat...

  6. On the Humidity Sensitivity of Hot-Wire Measurements

    DEFF Research Database (Denmark)

    Larsen, Søren Ejling; Busch, N. E.

    1980-01-01

    The influence of humidity changes on hot-wire measurements is discussed. Indications are that the humidity sensitivity parameters obtained by the authors in an earlier paper should be changed. This means, however, that the agreement between predicted and measured sensitivities ceases to exist...

  7. Relationship between relative humidity and the dew point ...

    African Journals Online (AJOL)

    This research was aimed at determining the relationship between relative humidity and the dew point temperature in Benin City, Edo State, Nigeria. The dew point temperature was approximated from the measured air temperature and relative humidity with the aid of a currently self-designed weather monitoring system.

  8. Modeling of humidity-related reliability in enclosures with electronics

    DEFF Research Database (Denmark)

    Hygum, Morten Arnfeldt; Popok, Vladimir

    2015-01-01

    Reliability of electronics that operate outdoor is strongly affected by environmental factors such as temperature and humidity. Fluctuations of these parameters can lead to water condensation inside enclosures. Therefore, modelling of humidity distribution in a container with air and freely exposed...

  9. Possible stretched exponential parametrization for humidity absorption in polymers.

    Science.gov (United States)

    Hacinliyan, A; Skarlatos, Y; Sahin, G; Atak, K; Aybar, O O

    2009-04-01

    Polymer thin films have irregular transient current characteristics under constant voltage. In hydrophilic and hydrophobic polymers, the irregularity is also known to depend on the humidity absorbed by the polymer sample. Different stretched exponential models are studied and it is shown that the absorption of humidity as a function of time can be adequately modelled by a class of these stretched exponential absorption models.

  10. New calculation method for thermodynamic properties of humid air in humid air turbine cycle – The general model and solutions for saturated humid air

    International Nuclear Information System (INIS)

    Wang, Zidong; Chen, Hanping; Weng, Shilie

    2013-01-01

    The article proposes a new calculation method for thermodynamic properties (i.e. specific enthalpy, specific entropy and specific volume) of humid air in humid air turbine cycle. The research pressure range is from 0.1 MPa to 5 MPa. The fundamental behaviors of dry air and water vapor in saturated humid air are explored in depth. The new model proposes and verifies the relationship between total gas mixture pressure and gas component pressures. This provides a good explanation of the fundamental behaviors of gas components in gas mixture from a new perspective. Another discovery is that the water vapor component pressure of saturated humid air equals P S , always smaller than its partial pressure (f·P S ) which was believed in the past researches. In the new model, “Local Gas Constant” describes the interaction between similar molecules. “Improvement Factor” is proposed for the first time by this article, and it quantitatively describes the magnitude of interaction between dissimilar molecules. They are combined to fully describe the real thermodynamic properties of humid air. The average error of Revised Dalton's Method is within 0.1% compared to experimentally-based data. - Highlights: • Our new model is suitable to calculate thermodynamic properties of humid air in HAT cycle. • Fundamental behaviors of dry air and water vapor in saturated humid air are explored in depth. • Local-Gas-Constant describes existing alone component and Improvement Factor describes interaction between different components. • The new model proposes and verifies the relationship between total gas mixture pressure and component pressures. • It solves saturated humid air thoroughly and deviates from experimental data less than 0.1%

  11. Indoor air humidity, air quality, and health - An overview.

    Science.gov (United States)

    Wolkoff, Peder

    2018-04-01

    There is a long-standing dispute about indoor air humidity and perceived indoor air quality (IAQ) and associated health effects. Complaints about sensory irritation in eyes and upper airways are generally among top-two symptoms together with the perception "dry air" in office environments. This calls for an integrated analysis of indoor air humidity and eye and airway health effects. This overview has reviewed the literature about the effects of extended exposure to low humidity on perceived IAQ, sensory irritation symptoms in eyes and airways, work performance, sleep quality, virus survival, and voice disruption. Elevation of the indoor air humidity may positively impact perceived IAQ, eye symptomatology, and possibly work performance in the office environment; however, mice inhalation studies do not show exacerbation of sensory irritation in the airways by low humidity. Elevated humidified indoor air appears to reduce nasal symptoms in patients suffering from obstructive apnea syndrome, while no clear improvement on voice production has been identified, except for those with vocal fatigue. Both low and high RH, and perhaps even better absolute humidity (water vapor), favors transmission and survival of influenza virus in many studies, but the relationship between temperature, humidity, and the virus and aerosol dynamics is complex, which in the end depends on the individual virus type and its physical/chemical properties. Dry and humid air perception continues to be reported in offices and in residential areas, despite the IAQ parameter "dry air" (or "wet/humid air") is semantically misleading, because a sensory organ for humidity is non-existing in humans. This IAQ parameter appears to reflect different perceptions among other odor, dustiness, and possibly exacerbated by desiccation effect of low air humidity. It is salient to distinguish between indoor air humidity (relative or absolute) near the breathing and ocular zone and phenomena caused by moisture

  12. Mars Science Laboratory (MSL) - First Results of Relative Humidity Observations

    Science.gov (United States)

    Genzer, Maria; Harri, Ari-Matti; Kemppinen, Osku; Gómez-Elvira, Javier; Renno, Nilton; Savijärvi, Hannu; Schmidt, Walter; Polkko, Jouni; Rodríquez-Manfredi, Jose Antonio; de la Torre Juárez, Manuel; Mischna, Michael; Martín-Torres, Javier; Haukka, Harri; Paz Zorzano-Mier, Maria; Rafkin, Scott; Paton, Mark; MSL Science Team

    2013-04-01

    The Mars Science laboratory (MSL) called Curiosity made a successful landing at Gale crater early August 2012. MSL has an environmental instrument package called the Rover Environmental Monitoring Station (REMS) as a part of its scientific payload. REMS comprises instrumentation for the observation of atmospheric pressure, temperature of the air, ground temperature, wind speed and direction, relative humidity, and UV measurements. The REMS instrument suite is described at length in [1]. We concentrate on describing the first results from the REMS relative humidity observations and comparison of the measurements with modeling results. The REMS humidity device is provided by the Finnish Meteorological Institute. It is based on polymeric capacitive humidity sensors developed by Vaisala Inc. The humidity device makes use of one transducer electronics section placed in the vicinity of the three (3) humidity sensor heads. The humidity device is mounted on the REMS boom 2 providing ventilation with the ambient atmosphere through a filter protecting the device from airborne dust. The absolute accuracy of the humidity device is temperature dependent, and is of the order of 2% at the temperature range of -30 to -10 °C, and of the order of 10% at the temperature range of -80 to -60 °C. This enables the investigations of atmospheric humidity variations of both diurnal and seasonal scale. The humidity device measurements will have a lag, when a step-wise change in humidity is taking place. This lag effect is increasing with decreasing temperature, and it is of the order of a few hours at the temperature of -75 °C. To compensate for the lag effect we used an algorithm developed by Mäkinen [2]. The humidity observations were validated after tedious efforts. This was needed to compensate for the artifacts of the transducer electronics. The compensation process includes an assumption that the relative humidity at Mars in the temperature range of 0 to -30 °C is about zero. The

  13. The climatic effect of explosive volcanic activity: Analysis of the historical data

    Science.gov (United States)

    Bryson, R. A.; Goodman, B. M.

    1982-01-01

    By using the most complete available records of direct beam radiation and volcanic eruptions, an historical analysis of the role of the latter in modulating the former was made. A very simple fallout and dispersion model was applied to the historical chronology of explosive eruptions. The resulting time series explains about 77 percent of the radiation variance, as well as suggests that tropical and subpolar eruptions are more important than mid-latitude eruptions in their impact on the stratospheric aerosol optical depth. The simpler climatic models indicate that past hemispheric temperature can be stimulated very well with volcanic and CO2 inputs and suggest that climate forecasting will also require volcano forecasting. There is some evidence that this is possible some years in advance.

  14. The effect of humidity on the detection of radon

    International Nuclear Information System (INIS)

    Money, M.; Heaton, B.

    1976-01-01

    As part of the investigation into the performance of a radon monitoring system the effect of altering the humidity on the levels of radon detected by the system whilst attempting to keep other factors constant, has been investigated. The variations in the levels of radon detected in four experiments, as the humidity of the surrounding atmosphere was artificially raised, are shown graphically together with the variations in temperature and water vapour pressure, as calculated from the relative humidity and saturation vapour pressure. In each case a general rise and fall in radon detected follows a similar rise and fall in humidity, but temperature rise has only a small effect on the radon emanation rate. As the levels of humidity do not alter the rate of emanation it is assumed that the efficiency of collection is altered in some way. Mechanisms are discussed. (U.K.)

  15. On the distribution of relative humidity in cirrus clouds

    Directory of Open Access Journals (Sweden)

    P. Spichtinger

    2004-01-01

    Full Text Available We have analysed relative humidity statistics from measurements in cirrus clouds taken unintentionally during the Measurement of OZone by Airbus In-service airCraft project (MOZAIC. The shapes of the in-cloud humidity distributions change from nearly symmetric in relatively warm cirrus (warmer than −40°C to considerably positively skew (i.e. towards high humidities in colder clouds. These results are in agreement to findings obtained recently from the INterhemispheric differences in Cirrus properties from Anthropogenic emissions (INCA campaign (Ovarlez et al., 2002. We interprete the temperature dependence of the shapes of the humidity distributions as an effect of the length of time a cirrus cloud needs from formation to a mature equilibrium stage, where the humidity is close to saturation. The duration of this transitional period increases with decreasing temperature. Hence cold cirrus clouds are more often met in the transitional stage than warm clouds.

  16. Effect of humidity on thoron adsorption in activated charcoal bed

    International Nuclear Information System (INIS)

    Sudeep Kumara, K.; Karunakara, N.; Yashodhara, I.; Sapra, B.K.; Sahoo, B.K.; Gaware, J.J.; Kanse, S.D.; Mayya, Y.S.

    2014-01-01

    Activated charcoal is a well-known adsorber of 222 Rn and 220 Rn gases. This property can be effectively used for remediation of these gases in the workplaces of uranium and thorium processing facilities. However, the adsorption on charcoal is sensitive to variation in temperature and humidity. The successful designing and characterization of adsorption systems require an adequate understanding of these sensitivities. The study has been carried out towards this end, to delineate the effect of relative humidity on the efficacy of 220 Rn mitigations in a charcoal bed. Air carrying 220 Rn from a Pylon source was passed through a column filled with coconut shell-based granular activated charcoal. The relative humidity of the air was controlled, and the transmission characteristics were examined at relative humidity varying from 45% to 60%. The mitigation factor was found to decrease significantly with an increase of humidity in the air. (author)

  17. A high sensitivity nanomaterial based SAW humidity sensor

    Energy Technology Data Exchange (ETDEWEB)

    Wu, T-T; Chou, T-H [Institute of Applied Mechanics, National Taiwan University, Taipei 106, Taiwan (China); Chen, Y-Y [Department of Mechanical Engineering, Tatung University, Taipei 104, Taiwan (China)], E-mail: wutt@ndt.iam.ntu.edu.tw

    2008-04-21

    In this paper, a highly sensitive humidity sensor is reported. The humidity sensor is configured by a 128{sup 0}YX-LiNbO{sub 3} based surface acoustic wave (SAW) resonator whose operating frequency is at 145 MHz. A dual delay line configuration is realized to eliminate external temperature fluctuations. Moreover, for nanostructured materials possessing high surface-to-volume ratio, large penetration depth and fast charge diffusion rate, camphor sulfonic acid doped polyaniline (PANI) nanofibres are synthesized by the interfacial polymerization method and further deposited on the SAW resonator as selective coating to enhance sensitivity. The humidity sensor is used to measure various relative humidities in the range 5-90% at room temperature. Results show that the PANI nanofibre based SAW humidity sensor exhibits excellent sensitivity and short-term repeatability.

  18. Diurnal Thermal Behavior of Pavements, Vegetation, and Water Pond in a Hot-Humid City

    Directory of Open Access Journals (Sweden)

    Xiaoshan Yang

    2015-12-01

    Full Text Available This study investigated the diurnal thermal behavior of several urban surfaces and landscape components, including pavements, vegetation, and a water pond. The field experiment was conducted in a university campus of Guangzhou, South China, which is characterized by a hot and humid summer. The temperature of ground surface and grass leaves and the air temperature and humidity from 0.1 to 1.5 m heights were measured for a period of 24 h under hot summer conditions. The results showed that the concrete and granite slab pavements elevated the temperature of the air above them throughout the day. In contrast, the trees and the pond lowered the air temperature near ground during the daytime but produced a slight warming effect during the nighttime. The influence of vegetation on air temperature and humidity is affected by the configurations of greenery. Compared to the open lawn, the grass shaded by trees was more effective in cooling and the mixture of shrub and grass created a stronger cooling effect during the nighttime. The knowledge of thermal behavior of various urban surfaces and landscape components is an important tool for planners and designers. If utilized properly, it can lead to climatic rehabilitation in urban areas and an improvement of the outdoor thermal environment.

  19. Incorporating residual temperature and specific humidity in predicting weather-dependent warm-season electricity consumption

    Science.gov (United States)

    Guan, Huade; Beecham, Simon; Xu, Hanqiu; Ingleton, Greg

    2017-02-01

    Climate warming and increasing variability challenges the electricity supply in warm seasons. A good quantitative representation of the relationship between warm-season electricity consumption and weather condition provides necessary information for long-term electricity planning and short-term electricity management. In this study, an extended version of cooling degree days (ECDD) is proposed for better characterisation of this relationship. The ECDD includes temperature, residual temperature and specific humidity effects. The residual temperature is introduced for the first time to reflect the building thermal inertia effect on electricity consumption. The study is based on the electricity consumption data of four multiple-street city blocks and three office buildings. It is found that the residual temperature effect is about 20% of the current-day temperature effect at the block scale, and increases with a large variation at the building scale. Investigation of this residual temperature effect provides insight to the influence of building designs and structures on electricity consumption. The specific humidity effect appears to be more important at the building scale than at the block scale. A building with high energy performance does not necessarily have low specific humidity dependence. The new ECDD better reflects the weather dependence of electricity consumption than the conventional CDD method.

  20. Dynamics of the temperature-humidity index in the Mediterranean basin

    Science.gov (United States)

    Segnalini, Maria; Nardone, Alessandro; Bernabucci, Umberto; Vitali, Andrea; Ronchi, Bruno; Lacetera, Nicola

    2011-03-01

    The study was aimed at describing the temperature humidity index (THI) dynamics over the Mediterranean basin for the period 1951-2007. The THI combines temperature and humidity into a single value, and may help to predict the effects of environmental warmth in farm animals. In particular, on the basis of THI values, numerous studies have been performed to establish thresholds for heat stress in dairy cows. The THI was calculated by using monthly mean values of temperature and humidity obtained from the National Center for Environmental Prediction/National Center for Atmospheric Research reanalysis project. The analysis demonstrated a high degree of heterogeneity of THI patterns over the Mediterranean basin, a strong north-south gradient, and an overall warming during the study period, which was particularly marked during summer seasons. Results indicated that several areas of the basin present summer THI values which were unfavorable to cow welfare and productivity, and that risk of heat stress for cows is generally greater in the countries of the south coast of the basin. Furthermore, THI data from the summer 2003 revealed that severe positive anomalies may impact areas normally characterized by a favorable climate for animal production. In conclusion, THI dynamics should be taken into careful consideration by farmers and policy makers operating in Mediterranean countries when planning investments in the sector of animal production. The investments should at least partially be directed towards implementation of adaptation measures, which may help to alleviate the impact of hot on farm animals welfare, performance and health.

  1. Water Collection from Air Humidity in Bahrain

    Directory of Open Access Journals (Sweden)

    Dahman. Nidal A.

    2017-01-01

    Full Text Available The Kingdom of Bahrain falls geographically in one of the driest regions in the world. Conventional fresh surface water bodies, such as rivers and lakes, are nonexistent and for water consumption, Bahrain prominently relies on the desalination of sea water. This paper presents an ongoing project that is being pursued by a group of student and their advising professors to investigate the viability of extracting water from air humidity. Dehumidifiers have been utilized as water extraction devices. Those devices have been distributed on six areas that were selected based on a rigorous geospatial modeling of historical meteorological data. The areas fall in residential and industrial neighborhoods that are located in the main island and the island of Muharraq. Water samples have been collected three times every week since May of 2016 and the collection process will continue until May of 2017. The collected water samples have been analyzed against numerous variables individually and in combinations including: amount of water collected per hour versus geographical location, amount of water collected per hour versus meteorological factors, suitability of collected water for potable human consumption, detection of air pollution in the areas of collection and the economy of this method of water collection in comparison to other nonconventional methods. An overview of the completed analysis results is presented in this paper.

  2. Comparisons of the tropospheric specific humidity from GPS radio occultations with ERA-Interim, NASA MERRA, and AIRS data

    Science.gov (United States)

    Vergados, Panagiotis; Mannucci, Anthony J.; Ao, Chi O.; Verkhoglyadova, Olga; Iijima, Byron

    2018-03-01

    We construct a 9-year data record (2007-2015) of the tropospheric specific humidity using Global Positioning System radio occultation (GPS RO) observations from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) mission. This record covers the ±40° latitude belt and includes estimates of the zonally averaged monthly mean specific humidity from 700 up to 400 hPa. It includes three major climate zones: (a) the deep tropics (±15°), (b) the trade winds belts (±15-30°), and (c) the subtropics (±30-40°). We find that the RO observations agree very well with the European Centre for Medium-Range Weather Forecasts Re-Analysis Interim (ERA-Interim), the Modern-Era Retrospective Analysis for Research and Applications (MERRA), and the Atmospheric Infrared Sounder (AIRS) by capturing similar magnitudes and patterns of variability in the monthly zonal mean specific humidity and interannual anomaly over annual and interannual timescales. The JPL and UCAR specific humidity climatologies differ by less than 15 % (depending on location and pressure level), primarily due to differences in the retrieved refractivity. In the middle-to-upper troposphere, in all climate zones, JPL is the wettest of all data sets, AIRS is the driest of all data sets, and UCAR, ERA-Interim, and MERRA are in very good agreement, lying between the JPL and AIRS climatologies. In the lower-to-middle troposphere, we present a complex behavior of discrepancies, and we speculate that this might be due to convection and entrainment. Conclusively, the RO observations could potentially be used as a climate variable, but more thorough analysis is required to assess the structural uncertainty between centers and its origin.

  3. Does the increased air humidity affect soil respiration and carbon stocks?

    Science.gov (United States)

    Kukumägi, Mai; Celi, Luisella; Said-Pullicino, Daniel; Kupper, Priit; Sõber, Jaak; Lõhmus, Krista; Kutti, Sander; Ostonen, Ivika

    2013-04-01

    Climate manipulation experiments at ecosystem-scale enable us to simulate, investigate and predict changes in carbon balance of forest ecosystems. Considering the predicted increase in air humidity and precipitation for northern latitudes, this work aimed at investigating the effect of increased air humidity on soil respiration, distribution of soil organic matter (SOM) among pools having different turnover times, and microbial, fine root and rhizome biomass. The study was carried out in silver birch (Betula pendula Roth.) and hybrid aspen (Populus tremula L. × P. tremuloides Michx.) stands in a Free Air Humidity Manipulation (FAHM) experimental facility containing three humidified (H; on average 7% above current ambient levels since 2008) and three control (C) plots. Soil respiration rates were measured monthly during the growing season using a closed dynamic chamber method. Density fractionation was adopted to separate SOM into two light fractions (free and aggregate-occluded particulate organic matter, fPOM and oPOM respectively), and one heavy fraction (mineral-associated organic matter, MOM). The fine root and rhizome biomass and microbial data are presented for silver birch stands only. In 2011, after 4 growing seasons of humidity manipulation soil organic carbon contents were significantly higher in C plots than H plot (13.5 and 12.5 g C kg-1, respectively), while soil respiration tended to be higher in the latter. Microbial biomass and basal respiration were 13 and 14% higher in H plots than in the C plots, respectively. Twice more fine roots of trees were estimated in H plots, while the total fine root and rhizome biomass (tree + understory) was similar in C and H plots. Fine root turnover was higher for both silver birch and understory roots in H plots. Labile SOM light fractions (fPOM and oPOM) were significantly smaller in H plots with respect to C plots (silver birch and hybrid aspen stands together), whereas no differences were observed in the

  4. Mixing of secondary organic aerosols versus relative humidity

    Science.gov (United States)

    Ye, Qing; Robinson, Ellis Shipley; Ding, Xiang; Ye, Penglin

    2016-01-01

    Atmospheric aerosols exert a substantial influence on climate, ecosystems, visibility, and human health. Although secondary organic aerosols (SOA) dominate fine-particle mass, they comprise myriad compounds with uncertain sources, chemistry, and interactions. SOA formation involves absorption of vapors into particles, either because gas-phase chemistry produces low-volatility or semivolatile products that partition into particles or because more-volatile organics enter particles and react to form lower-volatility products. Thus, SOA formation involves both production of low-volatility compounds and their diffusion into particles. Most chemical transport models assume a single well-mixed phase of condensing organics and an instantaneous equilibrium between bulk gas and particle phases; however, direct observations constraining diffusion of semivolatile organics into particles containing SOA are scarce. Here we perform unique mixing experiments between SOA populations including semivolatile constituents using quantitative, single-particle mass spectrometry to probe any mass-transfer limitations in particles containing SOA. We show that, for several hours, particles containing SOA from toluene oxidation resist exchange of semivolatile constituents at low relative humidity (RH) but start to lose that resistance above 20% RH. Above 40% RH, the exchange of material remains constant up to 90% RH. We also show that dry particles containing SOA from α-pinene ozonolysis do not appear to resist exchange of semivolatile compounds. Our interpretation is that in-particle diffusion is not rate-limiting to mass transfer in these systems above 40% RH. To the extent that these systems are representative of ambient SOA, we conclude that diffusion limitations are likely not common under typical ambient boundary layer conditions. PMID:27791066

  5. Mixing of secondary organic aerosols versus relative humidity.

    Science.gov (United States)

    Ye, Qing; Robinson, Ellis Shipley; Ding, Xiang; Ye, Penglin; Sullivan, Ryan C; Donahue, Neil M

    2016-10-24

    Atmospheric aerosols exert a substantial influence on climate, ecosystems, visibility, and human health. Although secondary organic aerosols (SOA) dominate fine-particle mass, they comprise myriad compounds with uncertain sources, chemistry, and interactions. SOA formation involves absorption of vapors into particles, either because gas-phase chemistry produces low-volatility or semivolatile products that partition into particles or because more-volatile organics enter particles and react to form lower-volatility products. Thus, SOA formation involves both production of low-volatility compounds and their diffusion into particles. Most chemical transport models assume a single well-mixed phase of condensing organics and an instantaneous equilibrium between bulk gas and particle phases; however, direct observations constraining diffusion of semivolatile organics into particles containing SOA are scarce. Here we perform unique mixing experiments between SOA populations including semivolatile constituents using quantitative, single-particle mass spectrometry to probe any mass-transfer limitations in particles containing SOA. We show that, for several hours, particles containing SOA from toluene oxidation resist exchange of semivolatile constituents at low relative humidity (RH) but start to lose that resistance above 20% RH. Above 40% RH, the exchange of material remains constant up to 90% RH. We also show that dry particles containing SOA from α-pinene ozonolysis do not appear to resist exchange of semivolatile compounds. Our interpretation is that in-particle diffusion is not rate-limiting to mass transfer in these systems above 40% RH. To the extent that these systems are representative of ambient SOA, we conclude that diffusion limitations are likely not common under typical ambient boundary layer conditions.

  6. A calibration facility to provide traceable calibration to upper air humidity measuring sensors

    Science.gov (United States)

    Cuccaro, Rugiada; Rosso, Lucia; Smorgon, Denis; Beltramino, Giulio; Fernicola, Vito

    2017-04-01

    Accurate knowledge and high quality measurement of the upper air humidity and of its profile in atmosphere is essential in many areas of the atmospheric research, for example in weather forecasting, environmental pollution studies and research in meteorology and climatology. Moving from the troposphere to the stratosphere, the water vapour amount varies between some percent to few part per million. For this reason, through the years, several methods and instruments have been developed for the measurement of the humidity in atmosphere. Among the instruments used for atmospheric sounding, radiosondes, airborne and balloon-borne chilled mirror hygrometer (CMH) and tunable diode laser absorption spectrometers (TDLAS) play a key role. To avoid the presence of unknown biases and systematic errors and to obtain accurate and reliable humidity measurements, these instruments need a SI-traceable calibration, preferably carried out in conditions similar to those expected in the field. To satisfy such a need, a new calibration facility has been developed at INRIM. The facility is based on a thermodynamic-based frost-point generator designed to achieve a complete saturation of the carrier gas with a single passage through an isothermal saturator. The humidity generator covers the frost point temperature range between -98 °C and -20 °C and is able to work at any controlled pressure between 200 hPa and 1000 hPa (corresponding to a barometric altitude between ground level and approximately 12000 m). The paper reports the work carried out to test the generator performances, discusses the results and presents the evaluation of the measurement uncertainty. The present work was carried out within the European Joint Research Project "MeteoMet 2 - Metrology for Essential Climate Variables" co-funded by the European Metrology Research Programme (EMRP). The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.

  7. Changes of fatty acid aerosol hygroscopicity induced by ozonolysis under humid conditions

    Directory of Open Access Journals (Sweden)

    O. Vesna

    2008-08-01

    Full Text Available Unsaturated fatty acids are important constituents of the organic fraction of atmospheric aerosols originating from biogenic or combustion sources. Oxidative processing of these may change their interaction with water and thus affect their effect on climate. The ozonolysis of oleic and arachidonic acid aerosol particles was studied under humid conditions in a flow reactor at ozone exposures close to atmospheric levels, at concentrations between 0.5 and 2 ppm. While oleic acid is a widely used proxy for such studies, arachidonic acid represents polyunsaturated fatty acids, which may decompose into hygroscopic products. The hygroscopic (diameter growth factor at 93% relative humidity (RH of the oxidized arachidonic particles increased up to 1.09 with increasing RH during the ozonolysis. In contrast, the growth factor of oleic acid was very low (1.03 at 93% RH and was almost invariant to the ozonolysis conditions, so that oleic acid is not a good model to observe oxidation induced changes of hygroscopicity under atmospheric conditions. We show for arachidonic acid particles that the hygroscopic changes induced by humidity during ozonolysis are accompanied by about a doubling of the ratio of carboxylic acid protons to aliphatic protons. We suggest that, under humid conditions, the reaction of water with the Criegee intermediates might open a pathway for the formation of smaller acids that lead to more significant changes in hygroscopicity. Thus the effect of water to provide a competing pathway during ozonolysis observed in this study should be motivation to include water, which is ubiquitously present in and around atmospheric particles, in future studies related to aerosol particle aging.

  8. Impact of Residential Mechanical Ventilation on Energy Cost and Humidity Control

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Eric [Building Science Corporation, Westford, MA (United States)

    2014-01-01

    Optimizing whole house mechanical ventilation as part of the Building Ameerica program's systems engineered approach to constructing housing has been an important subject of the program's research. Ventilation in residential buildings is one component of an effective, comprehensive strategy for creation and maintenance of a comfortable and healthy indoor air environment. The study described in this report is based on building energy modeling with an important focus on the indoor humidity impacts of ventilation. The modeling tools used were EnergyPlus version 7.1 (E+) and EnergyGauge USA (EGUSA). Twelve U.S. cities and five climate zones were represented. A total of 864 simulations (2*2*3*3*12= 864) were run using two building archetypes, two building leakage rates, two building orientations, three ventilation systems, three ventilation rates, and twelve climates.

  9. Horizontal Air-Ground Heat Exchanger Performance and Humidity Simulation by Computational Fluid Dynamic Analysis

    Directory of Open Access Journals (Sweden)

    Paolo Maria Congedo

    2016-11-01

    Full Text Available Improving energy efficiency in buildings and promoting renewables are key objectives of European energy policies. Several technological measures are being developed to enhance the energy performance of buildings. Among these, geothermal systems present a huge potential to reduce energy consumption for mechanical ventilation and cooling, but their behavior depending on varying parameters, boundary and climatic conditions is not fully established. In this paper a horizontal air-ground heat exchanger (HAGHE system is studied by the development of a computational fluid dynamics (CFD model. Summer and winter conditions representative of the Mediterranean climate are analyzed to evaluate operation and thermal performance differences. A particular focus is given to humidity variations as this parameter has a major impact on indoor air quality and comfort. Results show the benefits that HAGHE systems can provide in reducing energy consumption in all seasons, in summer when free-cooling can be implemented avoiding post air treatment using heat pumps.

  10. Passenger evaluation of the optimum balance between fresh air supply and humidity from 7-h exposures in a simulated aircraft cabin

    DEFF Research Database (Denmark)

    Strøm-Tejsen, Peter; Wyon, David Peter; Lagercrantz, Love Per

    2007-01-01

    A 21-seat section of an aircraft cabin with realistic pollution sources was built inside a climate chamber capable of providing fresh outside air at very low humidity. Maintaining a constant 200 l/s rate of total air supply, i.e. recircu-lated and make-up air, to the cabin, experiments simulating 7...

  11. Occupant evaluation of 7-hour exposures in a simulated aircraft cabin - Part 1: Optimum balance between fresh air supply and humidity

    DEFF Research Database (Denmark)

    Strøm-Tejsen, Peter; Wyon, David Peter; Lagercrantz, Love Per

    2005-01-01

    Low humidity in the aircraft cabin environment has been identified as a possible cause of symptoms experienced during long flights. A mock-up of a 21-seat section of an aircraft cabin with realistic pollution sources was built inside a climate chamber, capable of providing fresh outside air at very...

  12. Humidity sorption on natural building stone

    Science.gov (United States)

    Franzen, C.; Mirwald, P.

    2003-04-01

    processes, physical, chemical or biological, depend on the presence of water. Like most porous materials building stone respond on humidity by water uptake. The sorption isotherm represents the equilibrium moisture, specific for each material. The determination of the isotherm for stone of low and small porosity like marble is difficult. With the help of a newly developed water sorption analysis chamber [2], which allows the simultaneous measurement of 11 samples, good results on stone/rock samples have been obtained. Even at marble species with pore volumes lower than 0.4 % isotherms are measured. This analytical method offers new insights in the pore behaviour of low porosity materials. The advantages of this technique which supplements other techniques (e.g. BET, Hg-porosimetry) are: i) the testing agent is identical to the weathering agent, water; ii) the atmospheric parameters at the measurement reflect the natural conditions - thus no changes to the material properties have to be considered; iii) due to the small diameter of the water molecule (~0.28 nm), smaller pores are reached than e.g. with N2 (~0.31 nm). Sorption isotherms of sandstone (Baumberg, Obernkirchen, Groeden), granite (Brixen), and marble (Sterzing, Laas) are presented. Particular as to marbles the resolution is considerably higher. A previously observed negative hysteresis [3] seems an effect due to limited data resolution. [1] Snethlage, R. (1984) Steinkonservierung, Bayer. LA Denkmalpflege, Ah. 22, 203 S. [2] Griesser, U.J., Dillenz, J. (2002) Neuartiges, vollautomatisches Feuchtesorptionsprüfgerät mit hohem Probendurchsatz, Feuchtetag 2002, Weimar, 85-93. [3] Fimmel, R. (1996) Verwitterungsverhalten der alpinen Marmore von Laas und Sterzing, Diss. Univ. Ibk, 116 S.

  13. Is Obsidian Hydration Dating Affected by Relative Humidity?

    Science.gov (United States)

    Friedman, I.; Trembour, F.W.; Smith, G.I.; Smith, F.L.

    1994-01-01

    Experiments carried out under temperatures and relative humidities that approximate ambient conditions show that the rate of hydration of obsidian is a function of the relative humidity, as well as of previously established variables of temperature and obsidian chemical composition. Measurements of the relative humidity of soil at 25 sites and at depths of between 0.01 and 2 m below ground show that in most soil environments, at depths below about 0.25 m, the relative humidity is constant at 100%. We have found that the thickness of the hydrated layer developed on obsidian outcrops exposed to the sun and to relative humidities of 30-90% is similar to that formed on other portions of the outcrop that were shielded from the sun and exposed to a relative humidity of approximately 100%. Surface samples of obsidian exposed to solar heating should hydrate more rapidly than samples buried in the ground. However, the effect of the lower mean relative humidity experiences by surface samples tends to compensate for the elevated temperature, which may explain why obsidian hydration ages of surface samples usually approximate those derived from buried samples.

  14. Roles of inter-SWCNT junctions in resistive humidity response

    International Nuclear Information System (INIS)

    Zhang, Kang; Zou, Jianping; Zhang, Qing

    2015-01-01

    As a promising chemiresistor for gas sensing, the single-walled carbon nanotube (SWCNT) network has not yet been fully utilized for humidity detection. In this work, it is found that as humidity increases from 10% to 85%, the resistance of as-grown SWCNT networks first decreases and then increases. This non-monotonic resistive response to humidity limits their sensing capabilities. The competition between SWCNT resistance and inter-tube junction resistance changes is then found to be responsible for the non-monotonic resistive humidity responses. Moreover, creating sp"3 scattering centers on the SWCNT sidewall by monovalent functionalization of four-bromobenzene diazonium tetrafluoroborate is shown to be capable of eliminating the influence from the inter-tube junctions, resulting in a continuous resistance drop as humidity increases from 10% to 85%. Our results revealed the competing resistive humidity sensing process in as-grown SWCNT networks, which could also be helpful in designing and optimizing as-grown SWCNT networks for humidity sensors and other gas sensors. (paper)

  15. Mars Science Laboratory relative humidity observations: Initial results.

    Science.gov (United States)

    Harri, A-M; Genzer, M; Kemppinen, O; Gomez-Elvira, J; Haberle, R; Polkko, J; Savijärvi, H; Rennó, N; Rodriguez-Manfredi, J A; Schmidt, W; Richardson, M; Siili, T; Paton, M; Torre-Juarez, M De La; Mäkinen, T; Newman, C; Rafkin, S; Mischna, M; Merikallio, S; Haukka, H; Martin-Torres, J; Komu, M; Zorzano, M-P; Peinado, V; Vazquez, L; Urqui, R

    2014-09-01

    The Mars Science Laboratory (MSL) made a successful landing at Gale crater early August 2012. MSL has an environmental instrument package called the Rover Environmental Monitoring Station (REMS) as a part of its scientific payload. REMS comprises instrumentation for the observation of atmospheric pressure, temperature of the air, ground temperature, wind speed and direction, relative humidity (REMS-H), and UV measurements. We concentrate on describing the REMS-H measurement performance and initial observations during the first 100 MSL sols as well as constraining the REMS-H results by comparing them with earlier observations and modeling results. The REMS-H device is based on polymeric capacitive humidity sensors developed by Vaisala Inc., and it makes use of transducer electronics section placed in the vicinity of the three humidity sensor heads. The humidity device is mounted on the REMS boom providing ventilation with the ambient atmosphere through a filter protecting the device from airborne dust. The final relative humidity results appear to be convincing and are aligned with earlier indirect observations of the total atmospheric precipitable water content. The water mixing ratio in the atmospheric surface layer appears to vary between 30 and 75 ppm. When assuming uniform mixing, the precipitable water content of the atmosphere is ranging from a few to six precipitable micrometers. Atmospheric water mixing ratio at Gale crater varies from 30 to 140 ppmMSL relative humidity observation provides good dataHighest detected relative humidity reading during first MSL 100 sols is RH75.

  16. Temperature, humidity and time., Combined effects on radiochromic film dosimeters

    International Nuclear Information System (INIS)

    Abdel-Fattah, A.A.; Miller, A.

    1996-01-01

    The effects of both relative humidity and temperature during irradiation on the dose response of FWT-60-00 and Riso B3 radiochromic film dosimeters have been investigated in the relative humidity (RH) range 11-94% and temperature range 20-60 o C for irradiation by 60 Co photons and 10-MeV electrons. The results show that humidity and temperature cannot be treated as independent variables, rather there appears to be interdependence between absorbed dose, temperature, and humidity. Dose rate does not seem to play a significant role. The dependence of temperature during irradiation is + 0.25 ± 0.1% per o C for the FWT-60-00 dosimeters and +0.5 ± 0.1% per o C for Riso B3 dosimeters at temperatures between 20 and 50 o C and at relative humidities between 20 and 53%. At extreme conditions both with respect to temperature and to humidity, the dosimeters show much stronger dependences. Whenever possible one should use dosimeters sealed in pouches under controlled intermediate humidity conditions (30-50%) or, if that is impractical, one should maintain conditions of calibration as close as possible to the conditions of use. Without that precaution, severe dosimetry errors may result. (author)

  17. A Novel Passive Wireless Sensor for Concrete Humidity Monitoring.

    Science.gov (United States)

    Zhou, Shuangxi; Deng, Fangming; Yu, Lehua; Li, Bing; Wu, Xiang; Yin, Baiqiang

    2016-09-20

    This paper presents a passive wireless humidity sensor for concrete monitoring. After discussing the transmission of electromagnetic wave in concrete, a novel architecture of wireless humidity sensor, based on Ultra-High Frequency (UHF) Radio Frequency Identification (RFID) technology, is proposed for low-power application. The humidity sensor utilizes the top metal layer to form the interdigitated electrodes, which were then filled with polyimide as the humidity sensing layer. The sensor interface converts the humidity capacitance into a digital signal in the frequency domain. A two-stage rectifier adopts a dynamic bias-voltage generator to boost the effective gate-source voltage of the switches in differential-drive architecture. The clock generator employs a novel structure to reduce the internal voltage swing. The measurement results show that our proposed wireless humidity can achieve a high linearity with a normalized sensitivity of 0.55% %RH at 20 °C. Despite the high losses of concrete, the proposed wireless humidity sensor achieves reliable communication performances in passive mode. The maximum operating distance is 0.52 m when the proposed wireless sensor is embedded into the concrete at the depth of 8 cm. The measured results are highly consistent with the results measured by traditional methods.

  18. A Novel Passive Wireless Sensor for Concrete Humidity Monitoring

    Directory of Open Access Journals (Sweden)

    Shuangxi Zhou

    2016-09-01

    Full Text Available This paper presents a passive wireless humidity sensor for concrete monitoring. After discussing the transmission of electromagnetic wave in concrete, a novel architecture of wireless humidity sensor, based on Ultra-High Frequency (UHF Radio Frequency Identification (RFID technology, is proposed for low-power application. The humidity sensor utilizes the top metal layer to form the interdigitated electrodes, which were then filled with polyimide as the humidity sensing layer. The sensor interface converts the humidity capacitance into a digital signal in the frequency domain. A two-stage rectifier adopts a dynamic bias-voltage generator to boost the effective gate-source voltage of the switches in differential-drive architecture. The clock generator employs a novel structure to reduce the internal voltage swing. The measurement results show that our proposed wireless humidity can achieve a high linearity with a normalized sensitivity of 0.55% %RH at 20 °C. Despite the high losses of concrete, the proposed wireless humidity sensor achieves reliable communication performances in passive mode. The maximum operating distance is 0.52 m when the proposed wireless sensor is embedded into the concrete at the depth of 8 cm. The measured results are highly consistent with the results measured by traditional methods.

  19. Deformation of high performance concrete plate under humid tropical weather

    Science.gov (United States)

    Niken, C.; Elly, T.; Supartono, FX; Laksmi, I.

    2018-03-01

    This paper presents the relationship between surrounding relative humidity and temperature on deformation behavior of one sample concrete plate with compressive strength of 60MPa. This research was done in Indonesia that is in humid tropical weather. A specimens measuring 3000 mm × 1600 mm × 150 mm were used. The behavior was obtained by using four embedded vibrating wire strain gauges (VWESG). As a result there is a very strong relationship between humidity and deformation at the age range of 7 until 21 days. The largest deformation occurs in the corner and the fluctuation of deformation in side position is larger than in the corner and in the middle. The peaks of surrounding relative humidity were fully followed by the deepest valley of deformation on time in the corner, while in another position the range delay time was 8 - 11 hours. There is a strong relationship between surrounding temperature and deformation at the range of 7 until 14 days. The influenced of surrounding relative humidity to concrete behavior is faster and longer than surrounding temperature. The influence of surrounding temperature in humid tropical weather was shorter than in non-humid tropical weather.

  20. A Novel Passive Wireless Sensor for Concrete Humidity Monitoring

    Science.gov (United States)

    Zhou, Shuangxi; Deng, Fangming; Yu, Lehua; Li, Bing; Wu, Xiang; Yin, Baiqiang

    2016-01-01

    This paper presents a passive wireless humidity sensor for concrete monitoring. After discussing the transmission of electromagnetic wave in concrete, a novel architecture of wireless humidity sensor, based on Ultra-High Frequency (UHF) Radio Frequency Identification (RFID) technology, is proposed for low-power application. The humidity sensor utilizes the top metal layer to form the interdigitated electrodes, which were then filled with polyimide as the humidity sensing layer. The sensor interface converts the humidity capacitance into a digital signal in the frequency domain. A two-stage rectifier adopts a dynamic bias-voltage generator to boost the effective gate-source voltage of the switches in differential-drive architecture. The clock generator employs a novel structure to reduce the internal voltage swing. The measurement results show that our proposed wireless humidity can achieve a high linearity with a normalized sensitivity of 0.55% %RH at 20 °C. Despite the high losses of concrete, the proposed wireless humidity sensor achieves reliable communication performances in passive mode. The maximum operating distance is 0.52 m when the proposed wireless sensor is embedded into the concrete at the depth of 8 cm. The measured results are highly consistent with the results measured by traditional methods. PMID:27657070

  1. Effects of temperature and relative humidity on DNA methylation.

    Science.gov (United States)

    Bind, Marie-Abele; Zanobetti, Antonella; Gasparrini, Antonio; Peters, Annette; Coull, Brent; Baccarelli, Andrea; Tarantini, Letizia; Koutrakis, Petros; Vokonas, Pantel; Schwartz, Joel

    2014-07-01

    Previous studies have found relationships between DNA methylation and various environmental contaminant exposures. Associations with weather have not been examined. Because temperature and humidity are related to mortality even on non-extreme days, we hypothesized that temperature and relative humidity may affect methylation. We repeatedly measured methylation on long interspersed nuclear elements (LINE-1), Alu, and 9 candidate genes in blood samples from 777 elderly men participating in the Normative Aging Study (1999-2009). We assessed whether ambient temperature and relative humidity are related to methylation on LINE-1 and Alu, as well as on genes controlling coagulation, inflammation, cortisol, DNA repair, and metabolic pathway. We examined intermediate-term associations of temperature, relative humidity, and their interaction with methylation, using distributed lag models. Temperature or relative humidity levels were associated with methylation on tissue factor (F3), intercellular adhesion molecule 1 (ICAM-1), toll-like receptor 2 (TRL-2), carnitine O-acetyltransferase (CRAT), interferon gamma (IFN-γ), inducible nitric oxide synthase (iNOS), and glucocorticoid receptor, LINE-1, and Alu. For instance, a 5°C increase in 3-week average temperature in ICAM-1 methylation was associated with a 9% increase (95% confidence interval: 3% to 15%), whereas a 10% increase in 3-week average relative humidity was associated with a 5% decrease (-8% to -1%). The relative humidity association with ICAM-1 methylation was stronger on hot days than mild days. DNA methylation in blood cells may reflect biological effects of temperature and relative humidity. Temperature and relative humidity may also interact to produce stronger effects.

  2. Outdoor thermal comfort in public space in warm-humid Guayaquil, Ecuador

    Science.gov (United States)

    Johansson, Erik; Yahia, Moohammed Wasim; Arroyo, Ivette; Bengs, Christer

    2018-03-01

    The thermal environment outdoors affects human comfort and health. Mental and physical performance is reduced at high levels of air temperature being a problem especially in tropical climates. This paper deals with human comfort in the warm-humid city of Guayaquil, Ecuador. The main aim was to examine the influence of urban micrometeorological conditions on people's subjective thermal perception and to compare it with two thermal comfort indices: the physiologically equivalent temperature (PET) and the standard effective temperature (SET*). The outdoor thermal comfort was assessed through micrometeorological measurements of air temperature, humidity, mean radiant temperature and wind speed together with a questionnaire survey consisting of 544 interviews conducted in five public places of the city during both the dry and rainy seasons. The neutral and preferred values as well as the upper comfort limits of PET and SET* were determined. For both indices, the neutral values and upper thermal comfort limits were lower during the rainy season, whereas the preferred values were higher during the rainy season. Regardless of season, the neutral values of PET and SET* are above the theoretical neutral value of each index. The results show that local people accept thermal conditions which are above acceptable comfort limits in temperate climates and that the subjective thermal perception varies within a wide range. It is clear, however, that the majority of the people in Guayaquil experience the outdoor thermal environment during daytime as too warm, and therefore, it is important to promote an urban design which creates shade and ventilation.

  3. New recommendations for building in tropical climates

    Energy Technology Data Exchange (ETDEWEB)

    Waal, H.B. de (ISOVER BV, Cappelle a/d IJssel (Netherlands))

    1993-07-01

    Traditional recommendations for building a thermally efficient or comfortable building in a tropical climate are briefly summarized. They suffer from three main drawbacks; they are not quantitative, partly incorrect and only for two climates; the hot dry and the warm humid. A new climate classification, made up of forty tropical climates is presented. Eight building elements, which affect the thermal system of a building, are distinguished. The method by which the new recommendations are derived, is discussed. The new recommendations are briefly presented. (Author)

  4. A distribution law for relative humidity in the upper troposphere and lower stratosphere derived from three years of MOZAIC measurements

    Directory of Open Access Journals (Sweden)

    K. Gierens

    1999-09-01

    Full Text Available Data from three years of MOZAIC measurements made it possible to determine a distribution law for the relative humidity in the upper troposphere and lower stratosphere. Data amounting to 13.5% of the total were obtained in regions with ice supersaturation. Troposphere and stratosphere are distinguished by an ozone concentration of 130 ppbv as threshold. The probability of measuring a certain amount of ice supersaturation in the troposphere decreases exponentially with the degree of ice supersaturation. The probability of measuring a certain relative humidity in the stratosphere (both with respect to water and ice decreases exponentially with the relative humidity. A stochastic model that naturally leads to the exponential distribution is provided. Mean supersaturation in the troposphere is about 15%, whereas ice nucleation requires 30% supersaturation on the average. This explains the frequency of regions in which aircraft induce persistent contrails but which are otherwise free of clouds. Ice supersaturated regions are 3-4 K colder and contain more than 50% more vapour than other regions in the upper troposphere. The stratospheric air masses sampled are dry, as expected, having mean relative humidity over water of 12% and over ice of 23%, respectively. However, 2% of the stratospheric data indicate ice supersaturation. As the MOZAIC measurements have been obtained on commercial flights mainly between Europe and North America, the data do not provide a complete global picture, but the exponential character of the distribution laws found is probably valid globally. Since water vapour is the most important greenhouse gas and since it might enhance the anthropogenic greenhouse effects via positive feedback mechanisms, it is important to represent its distribution correctly in climate models. The discovery of the distribution law of the relative humidity makes possible simple tests to show whether the hydrological cycle in climate models is

  5. Behavior of HEPA filters under high humidity airflows

    International Nuclear Information System (INIS)

    Ricketts, C.I.

    1992-10-01

    To help determine and improve the safety margins of High Efficiency Particulate Air (HEPA) filter units in nuclear facilities under possible accident conditions, the structural limits and failure mechanisms of filter in high-humidity airflows were established and the fundamental physical phenomena underlying filter failure or malfunction in humid air were identified. Empirical models for increases in filter pressure drop with time in terms of the relevant airstream parameters were also developed. The weaknesses of currently employed humidity countermeasures used in filter protection are discussed and fundamental explanations for reported filter failures in normal service are given. (orig./DG) [de

  6. Influence of humidity on the graphene band gap

    International Nuclear Information System (INIS)

    Zakaryan, H.A.; Aroutiounian, V.M.

    2015-01-01

    Influences of the humidity on graphene properties are studied and comparisons of graphene and polymer humidity sensors are carried out. Graphene sensors have remarkable response compare to nanoporous polymer membranes. The resistance of polymer sensors is 150 GOhm and decreases in 7.5 times at 60 per cent of the relative humidity. For graphene, resistance drops 4 times starting from ~100 kOhm. This is connected with the extension of graphene band gap. The reason of this is adsorbed water, which can create defects in the lattice or can transfer charge which depends on relative position of HOMO/LUMO of water and Dirac point of graphene

  7. Dynamics of electrostatically driven granular media: Effects of humidity

    International Nuclear Information System (INIS)

    Howell, D. W.; Aronson, Igor S.; Crabtree, G. W.

    2001-01-01

    We performed experimental studies of the effect of humidity on the dynamics of electrostatically driven granular materials. Both conducting and dielectric particles undergo a phase transition from an immobile state (granular solid) to a fluidized state (granular gas) with increasing applied field. Spontaneous precipitation of solid clusters from the gas phase occurs as the external driving is decreased. The clustering dynamics in conducting particles is primarily controlled by screening of the electric field but is aided by cohesion due to humidity. It is shown that humidity effects dominate the clustering process with dielectric particles

  8. Study of some Mg-based ferrites as humidity sensors

    International Nuclear Information System (INIS)

    Rezlescu, N; Rezlescu, E; Doroftei, C; Popa, P D

    2005-01-01

    The micostructure and humidity sensitivity of MgFe 2 O 4 + CaO, Mg 0.5 Cu 0.5 Fe 1.8 Ga 0.2 O 4 , Mg 0.5 Zn 0.5 Fe 2 O 4 + KCl and MgMn 0.2 Fe 1.8 O 4 ferrites were investigated. We have found that the humidity sensitivity largely depends on composition, crystallite size, surface area and porosity. The best results concerning humidity sensitivity were obtained for MgMn 0.2 Fe 1.8 O 4 ferrite

  9. Numerical Modelling Of Humid Air Flow Around A Porous Body

    Directory of Open Access Journals (Sweden)

    Bohojło-Wiśniewska Aneta

    2015-09-01

    Full Text Available This paper presents an example of humid air flow around a single head of Chinese cabbage under conditions of complex heat transfer. This kind of numerical simulation allows us to create a heat and humidity transfer model between the Chinese cabbage and the flowing humid air. The calculations utilize the heat transfer model in porous medium, which includes the temperature difference between the solid (vegetable tissue and fluid (air phases of the porous medium. Modelling and calculations were performed in ANSYS Fluent 14.5 software.

  10. [An early warning method of cucumber downy mildew in solar greenhouse based on canopy temperature and humidity modeling].

    Science.gov (United States)

    Wang, Hui; Li, Mei-lan; Xu, Jian-ping; Chen, Mei-xiang; Li, Wen-yong; Li, Ming

    2015-10-01

    The greenhouse environmental parameters can be used to establish greenhouse nirco-climate model, which can combine with disease model for early warning, with aim of ecological controlling diseases to reduce pesticide usage, and protecting greenhouse ecological environment to ensure the agricultural product quality safety. Greenhouse canopy leaf temperature and air relative humidity, models were established using energy balance and moisture balance principle inside the greenhouse. The leaf temperature model considered radiation heat transfer between the greenhouse crops, wall, soil and cover, plus the heat exchange caused by indoor net radiation and crop transpiration. Furthermore, the water dynamic balance in the greenhouse including leaf transpiration, soil evaporation, cover and leaf water vapor condensation, was considered to develop a relative humidity model. The primary infection and latent period warning models for cucumber downy mildew (Pseudoperonospora cubensis) were validated using the results of the leaf temperature and relative humidity model, and then the estimated disease occurrence date of cucumber downy mildew was compared with actual disease occurrence date of field observation. Finally, the results were verified by the measured temperature and humidity data of September and October, 2014. The results showed that the root mean square deviations (RMSDs) of the measured and estimated leaf temperature were 0.016 and 0.024 °C, and the RMSDs of the measured and estimated air relative humidity were 0.15% and 0.13%, respectively. Combining the result of estimated temperature and humidity models, a cucumber disease early warning system was established to forecast the date of disease occurrence, which met with the real date. Thus, this work could provide the micro-environment data for the early warning system of cucumber diseases in solar greenhouses.

  11. Effects of temporal changes in climate variables on crop production ...

    African Journals Online (AJOL)

    Climate variability and change have been implicated to have significant impacts on global and regional food production particularly the common stable food crops performance in tropical sub-humid climatic zone. However, the extent and nature of these impacts still remain uncertain. In this study, records of crop yields and ...

  12. Relationship between climate conditions and nosocomial infection ...

    African Journals Online (AJOL)

    Background: Nosocomial infections constitute a global health problem. Objective: To explore the relationship between nosocomial infection rates (NIRs) and climatic factors including temperature and relative humidity in Guangzhou area of China. Methods: 30892 patients in our hospital in 2009 were investigated for ...

  13. Humidity measurement in industrial and non-industrial processes

    International Nuclear Information System (INIS)

    Heinze, D.

    1990-01-01

    The article presents a concise survey of continuous measuring techniques for determination of humidity or moisture contents in gases or solids, including techniques that apply neutron sources and the neutron slowing-down effect. (HP) [de

  14. NOS CO-OPS Meteorological Data, Relative Humidity, 6-Minute

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has Relative Humidity data from NOAA NOS Center for Operational Oceanographic Products and Services (CO-OPS). WARNING: These preliminary data have not...

  15. Passive Wireless SAW Humidity Sensors and System, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Phase I demonstrated the technical feasibility of creating surface acoustic wave (SAW) based humidity sensors that respond rapidly (under 0.5 second) and reversibly...

  16. Bacterial pleomorphism and competition in a relative humidity gradient

    NARCIS (Netherlands)

    de Goffau, Marcus C.; Yang, Xiaomei; van Dijl, Jan Maarten; Harmsen, Hermie J. M.

    The response of different bacterial species to reduced water availability was studied using a simple relative humidity gradient technique. Interestingly, distinct differences in morphology and growth patterns were observed between populations of the same species growing at different relative

  17. Searching for new solutions Humidity measurements in the environments

    Directory of Open Access Journals (Sweden)

    Gianina Creţu

    2008-05-01

    Full Text Available More attention is nowadays being paid to thequality of the air we breathe, resulting in an increasingneed for humidity measurements in the home and officeenvironments. Maintaining the proper level of relativehumidity is also necessary to avoid conditions of extremehumidity condensation in buildings.The facts that construction problems and excessive waterand humidity often go together is well-known around theworld today. Moisture and water damage is a wellknown problem in construction in many countries.Problems of all construction are caused by humidity and50 per cent of all buildings have some kind of moisturerelatedproblems. Growing awareness of percentages suchas these has led to greater attention being paid toconstruction humidity and its measurement throughoutthe world in recent years.This paper presents a condensed review of nowadayshumidity sensors technology, problem implicated andsome modern tendencies.

  18. Nanostructured Humidity Sensor for Spacecraft Life Support Systems, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Humidity is a critical variable for monitoring and control on extended duration missions because it can affect the operation and efficiency of closed loop life...

  19. Desiccant wheel thermal performance modeling for indoor humidity optimal control

    International Nuclear Information System (INIS)

    Wang, Nan; Zhang, Jiangfeng; Xia, Xiaohua

    2013-01-01

    Highlights: • An optimal humidity control model is formulated to control the indoor humidity. • MPC strategy is used to implement the optimal operation solution. • Practical applications of the MPC strategy is illustrated by the case study. - Abstract: Thermal comfort is an important concern in the energy efficiency improvement of commercial buildings. Thermal comfort research focuses mostly on temperature control, but humidity control is an important aspect to maintain indoor comfort too. In this paper, an optimal humidity control model (OHCM) is presented. Model predictive control (MPC) strategy is applied to implement the optimal operation of the desiccant wheel during working hours of a commercial building. The OHCM is revised to apply the MPC strategy. A case is studied to illustrate the practical applications of the MPC strategy

  20. Fabrication and Characterization of Polyaniline/PVA Humidity Microsensors

    Directory of Open Access Journals (Sweden)

    Ming-Zhi Yang

    2011-08-01

    Full Text Available This study presents the fabrication and characterization of a humidity microsensor that consists of interdigitated electrodes and a sensitive film. The area of the humidity microsensor is about 2 mm2. The sensitive film is polyaniline doping polyvinyl alcohol (PVA that is prepared by the sol-gel method, and the film has nanofiber and porous structures that help increase the sensing reaction. The commercial 0.35 mm Complimentary Metal Oxide Semiconductor (CMOS process is used to fabricate the humidity microsensor. The sensor needs a post-CMOS process to etch the sacrificial layer and to coat the sensitive film on the interdigitated electrodes. The sensor produces a change in resistance as the polyaniline/PVA film absorbs or desorbs vapor. Experimental results show that the sensitivity of the humidity sensor is about 12.6 kΩ/%RH at 25 °C.

  1. Preparation of an efficient humidity indicating silica gel from rice ...

    Indian Academy of Sciences (India)

    Administrator

    Department of Ceramic Engineering, National Institute of Technology, Rourkela 769 008, ... An efficient humidity indicating silica gel was prepared using rice husk ash as a raw material via ... white or colourless and shows no changes of colour.

  2. The Impacts of Multiple Simultaneous Climate Variations

    Science.gov (United States)

    2016-12-01

    in the ITCZ and SPCZ, and between the subtropical high and subpolar lows where the extratropical storm tracks occur. Lower PR values tend to occur...especially over and near the maritime continent and Amazon, in the ITCZ and SPCZ, and in the extratropical storm tracks over the North Pacific and...gradient and low tropospheric winds are strong (cf. Figure 9)—for example, between the subtropical highs and subpolar lows where the extratropical storm

  3. Multi-channel fiber optic dew and humidity sensor

    Science.gov (United States)

    Limodehi, Hamid E.; Mozafari, Morteza; Amiri, Hesam; Légaré, François

    2018-03-01

    In this article, we introduce a multi-channel fiber optic dew and humidity sensor which works using a novel method based on relation between surface plasmon resonance (SPR) and water vapor condensation. The proposed sensor can instantly detect moisture or dew formation through its fiber optic channels, separately situated in different places. It enables to simultaneously measure the ambient Relative Humidity (RH) and dew point temperature of several environments with accuracy of 5%.

  4. Enhancement of humidity sensitivity of graphene through functionalization with polyethylenimine

    International Nuclear Information System (INIS)

    Ben Aziza, Zeineb; Zhang, Kang; Baillargeat, Dominique; Zhang, Qing

    2015-01-01

    In this work, we show that the sensing performance of graphene based humidity sensors can be largely improved through polymer functionalization. Chemical vapor deposited graphene is functionalized with amine rich polymer, leading to electron transfer from amine groups in the polymer to graphene. The functionalized graphene humidity sensor has demonstrated good sensitivity, recovery, and repeatability. Charge transfer between the functionalized graphene and water molecules and the sensing mechanism are studied systemically using field effect transistor geometry and scanning Kelvin probe microscopy

  5. Humidity Sensors Printed on Recycled Paper and Cardboard

    Directory of Open Access Journals (Sweden)

    Matija Mraović

    2014-07-01

    Full Text Available Research, design, fabrication and results of various screen printed capacitive humidity sensors is presented in this paper. Two types of capacitive humidity sensors have been designed and fabricated via screen printing on recycled paper and cardboard, obtained from the regional paper and cardboard industry. As printing ink, commercially available silver nanoparticle-based conductive ink was used. A considerable amount of work has been devoted to the humidity measurement methods using paper as a dielectric material. Performances of different structures have been tested in a humidity chamber. Relative humidity in the chamber was varied in the range of 35%–80% relative humidity (RH at a constant temperature of 23 °C. Parameters of interest were capacitance and conductance of each sensor material, as well as long term behaviour. Process reversibility has also been considered. The results obtained show a mainly logarithmic response of the paper sensors, with the only exception being cardboard-based sensors. Recycled paper-based sensors exhibit a change in value of three orders of magnitude, whereas cardboard-based sensors have a change in value of few 10s over the entire scope of relative humidity range (RH 35%–90%. Two different types of capacitor sensors have been investigated: lateral (comb type sensors and modified, perforated flat plate type sensors. The objective of the present work was to identify the most important factors affecting the material performances with humidity, and to contribute to the development of a sensor system supported with a Radio Frequency Identification (RFID chip directly on the material, for use in smart packaging applications. Therefore, the authors built a passive and a battery-supported wireless module based on SL900A smart sensory tag’s IC to achieve UHF-RFID functionality with data logging capability.

  6. Variations of relative humidity in relation to meningitis in Africa

    Science.gov (United States)

    Seefeldt, M. W.; Hopson, T. M.

    2011-12-01

    The meningitis belt is a region covering Sub-Saharan Africa from the Sahel of West Africa eastward to western Ethiopia. The region is prone to meningitis epidemics during the dry season extending from approximately January to May, depending on the region. Relative humidity has been found to be a critical environmental factor indicating the susceptibility of a region to meningitis epidemics. This study evaluates the variation of relative humidity across West Africa over 30 dry-seasons (1979 - 2009) using the NASA-MERRA dataset. The method of self-organizing maps is employed to characterize the changes in relative humidity patterns across the region within a given dry season as well as changes over the 30 years. A general pattern of changes in relative humidity is indicated as the rainbelt retreats to the south at the onset of the dry season and then returns to the region at the end of the dry season. Within each dry season there is a unique pattern. The climatological conditions of relative humidity at the onset of the dry season provide an indication of the moisture environment for the entire dry season. Year to year variation in the relative humidity patterns are found to be gradual. Future applications involve using the results from the SOM evaluation to be used for future decisions involving prevention of meningitis epidemics.

  7. A Humidity Sensing Organic-Inorganic Composite for Environmental Monitoring

    Directory of Open Access Journals (Sweden)

    Khasan S. Karimov

    2013-03-01

    Full Text Available In this paper, we present the effect of varying humidity levels on the electrical parameters and the multi frequency response of the electrical parameters of an organic-inorganic composite (PEPC+NiPc+Cu2O-based humidity sensor. Silver thin films (thickness ~200 nm were primarily deposited on plasma cleaned glass substrates by the physical vapor deposition (PVD technique. A pair of rectangular silver electrodes was formed by patterning silver film through standard optical lithography technique. An active layer of organic-inorganic composite for humidity sensing was later spun coated to cover the separation between the silver electrodes. The electrical characterization of the sensor was performed as a function of relative humidity levels and frequency of the AC input signal. The sensor showed reversible changes in its capacitance with variations in humidity level. The maximum sensitivity ~31.6 pF/%RH at 100 Hz in capacitive mode of operation has been attained. The aim of this study was to increase the sensitivity of the previously reported humidity sensors using PEPC and NiPc, which has been successfully achieved.

  8. Humidity correction in the standard measurement of exposure

    International Nuclear Information System (INIS)

    Ibaraki, Yasuyuki; Katoh, Akira

    1980-01-01

    This paper deals with the humidity correction to be made in the standard measurement of the exposure to the measured ionization current in the humid air for the purpose of excluding the influence of the water vapour that is not included in the definition of the exposure. First, formulae giving the humidity correction factors for a parallel plate free air chamber and a cavity chamber have been derived respectively in the case where the contributions of air and water vapour to the ionization are independent. Next, in the case where the contributions are not independent, i.e., the Jesse effect is taken into account, a formula to obtain the W-value for humid air has been derived on the basis of the Niatel's experimental result. Using this formula, formulae to obtain the humidity correction factors for the free air chamber and the cavity chamber are derived. The humidity calculated by the latter formulae show good agreements with the results by Niatel and Guiho, respectively. (author)

  9. Humidity effects on scanning polarization force microscopy imaging

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Yue, E-mail: shenyue@isl.ac.cn [Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Key Laboratory of Salt Lake Resources Chemistry of Qinghai Province, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, Qinghai 810008 (China); Key Laboratory of Interfacial Physics and Technology of Chinese Academy of Sciences, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Zhou, Yuan, E-mail: zhouy@isl.ac.cn [Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Key Laboratory of Salt Lake Resources Chemistry of Qinghai Province, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, Qinghai 810008 (China); Sun, Yanxia; Zhang, Lijuan [Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Key Laboratory of Salt Lake Resources Chemistry of Qinghai Province, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, Qinghai 810008 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wang, Ying; Hu, Jun; Zhang, Yi [Key Laboratory of Interfacial Physics and Technology of Chinese Academy of Sciences, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2017-08-01

    Highlights: • The humidity dramatically affects the contrast of scanning polarization force microscopy (SPFM) imaging on mica surface. • This influence roots in the sensitive dielectric constant of mica surface to the humidity change. • A strategy of controllable and repeatable imaging the local dielectric properties of nanomaterials with SPFM is proposed. - Abstract: Scanning polarization force microscopy (SPFM) is a useful surface characterization technique to visually characterize and distinguish nanomaterial with different local dielectric properties at nanometer scale. In this paper, taking the individual one-atom-thick graphene oxide (GO) and reduced graphene oxide (rGO) sheets on mica as examples, we described the influences of environmental humidity on SPFM imaging. We found that the apparent heights (AHs) or contrast of SPFM imaging was influenced significantly by relative humidity (RH) at a response time of a few seconds. And this influence rooted in the sensitive dielectric constant of mica surface to the RH change. While dielectric properties of GO and rGO sheets were almost immune to the humidity change. In addition, we gave the method to determine the critical humidity at which the contrast conversion happened under different conditions. And this is important to the contrast control and repeatable imaging of SPFM through RH adjusting. These findings suggest a strategy of controllable and repeatable imaging the local dielectric properties of nanomaterials with SPFM, which is critically important for further distinguishment, manipulation, electronic applications, etc.

  10. A CMOS smart temperature and humidity sensor with combined readout.

    Science.gov (United States)

    Eder, Clemens; Valente, Virgilio; Donaldson, Nick; Demosthenous, Andreas

    2014-09-16

    A fully-integrated complementary metal-oxide semiconductor (CMOS) sensor for combined temperature and humidity measurements is presented. The main purpose of the device is to monitor the hermeticity of micro-packages for implanted integrated circuits and to ensure their safe operation by monitoring the operating temperature and humidity on-chip. The smart sensor has two modes of operation, in which either the temperature or humidity is converted into a digital code representing a frequency ratio between two oscillators. This ratio is determined by the ratios of the timing capacitances and bias currents in both oscillators. The reference oscillator is biased by a current whose temperature dependency is complementary to the proportional to absolute temperature (PTAT) current. For the temperature measurement, this results in an exceptional normalized sensitivity of about 0.77%/°C at the accepted expense of reduced linearity. The humidity sensor is a capacitor, whose value varies linearly with relative humidity (RH) with a normalized sensitivity of 0.055%/% RH. For comparison, two versions of the humidity sensor with an area of either 0.2 mm2 or 1.2 mm2 were fabricated in a commercial 0.18 μm CMOS process. The on-chip readout electronics operate from a 5 V power supply and consume a current of approximately 85 µA.

  11. Predicting forest attributes from climate data using a recursive partitioning and regression tree algorithm

    Science.gov (United States)

    Greg C. Liknes; Christopher W. Woodall; Charles H. Perry

    2009-01-01

    Climate information frequently is included in geospatial modeling efforts to improve the predictive capability of other data sources. The selection of an appropriate climate data source requires consideration given the number of choices available. With regard to climate data, there are a variety of parameters (e.g., temperature, humidity, precipitation), time intervals...

  12. Assessment of climate change scenarios for Saudi Arabia using data from global climate models

    International Nuclear Information System (INIS)

    Husain, T.; Chowdhury, S.

    2009-01-01

    This study assesses available scientific information and data to predict changes in the climatic parameters in Saudi Arabia for understanding the impacts for mitigation and/or adaptation. Meteorological data from 26 synoptic stations were analyzed in this study. Various climatic change scenarios were reviewed and A 2 and B 2 climatic scenario families were selected. In order to assess long-term global impact, global climatic models were used to simulate changes in temperature, precipitation, relative humidity, solar radiation, and wind circulation. Using global climate model (GCM), monthly time series data was retrieved for Longitude 15 o N to 35 o N and 32.5 o E to 60 o E covering the Kingdom of Saudi Arabia from 1970 to 2100 for all grids. Taking averages of 1970 to 2003 as baseline, change in temperature, relative humidity and precipitation were estimated for the base period. A comparative evaluation was performed for predictive capabilities of these models for temperature, precipitation and relative humidity. Available meteorological data from 1970 to 2003 was used to determine trends. This paper discusses the inconsistency in these parameters for decision-making and recommends future studies by linking global climate models with a suitable regional climate modeling tool. (author)

  13. Estimating irrigation water use in the humid eastern United States

    Science.gov (United States)

    Levin, Sara B.; Zarriello, Phillip J.

    2013-01-01

    Accurate accounting of irrigation water use is an important part of the U.S. Geological Survey National Water-Use Information Program and the WaterSMART initiative to help maintain sustainable water resources in the Nation. Irrigation water use in the humid eastern United States is not well characterized because of inadequate reporting and wide variability associated with climate, soils, crops, and farming practices. To better understand irrigation water use in the eastern United States, two types of predictive models were developed and compared by using metered irrigation water-use data for corn, cotton, peanut, and soybean crops in Georgia and turf farms in Rhode Island. Reliable metered irrigation data were limited to these areas. The first predictive model that was developed uses logistic regression to predict the occurrence of irrigation on the basis of antecedent climate conditions. Logistic regression equations were developed for corn, cotton, peanut, and soybean crops by using weekly irrigation water-use data from 36 metered sites in Georgia in 2009 and 2010 and turf farms in Rhode Island from 2000 to 2004. For the weeks when irrigation was predicted to take place, the irrigation water-use volume was estimated by multiplying the average metered irrigation application rate by the irrigated acreage for a given crop. The second predictive model that was developed is a crop-water-demand model that uses a daily soil water balance to estimate the water needs of a crop on a given day based on climate, soil, and plant properties. Crop-water-demand models were developed independently of reported irrigation water-use practices and relied on knowledge of plant properties that are available in the literature. Both modeling approaches require accurate accounting of irrigated area and crop type to estimate total irrigation water use. Water-use estimates from both modeling methods were compared to the metered irrigation data from Rhode Island and Georgia that were used to

  14. Fabrication and Characterization of a CMOS-MEMS Humidity Sensor

    Science.gov (United States)

    Dennis, John-Ojur; Ahmed, Abdelaziz-Yousif; Khir, Mohd-Haris

    2015-01-01

    This paper reports on the fabrication and characterization of a Complementary Metal Oxide Semiconductor-Microelectromechanical System (CMOS-MEMS) device with embedded microheater operated at relatively elevated temperatures (40 °C to 80 °C) for the purpose of relative humidity measurement. The sensing principle is based on the change in amplitude of the device due to adsorption or desorption of humidity on the active material layer of titanium dioxide (TiO2) nanoparticles deposited on the moving plate, which results in changes in the mass of the device. The sensor has been designed and fabricated through a standard 0.35 µm CMOS process technology and post-CMOS micromachining technique has been successfully implemented to release the MEMS structures. The sensor is operated in the dynamic mode using electrothermal actuation and the output signal measured using a piezoresistive (PZR) sensor connected in a Wheatstone bridge circuit. The output voltage of the humidity sensor increases from 0.585 mV to 30.580 mV as the humidity increases from 35% RH to 95% RH. The output voltage is found to be linear from 0.585 mV to 3.250 mV as the humidity increased from 35% RH to 60% RH, with sensitivity of 0.107 mV/% RH; and again linear from 3.250 mV to 30.580 mV as the humidity level increases from 60% RH to 95% RH, with higher sensitivity of 0.781 mV/% RH. On the other hand, the sensitivity of the humidity sensor increases linearly from 0.102 mV/% RH to 0.501 mV/% RH with increase in the temperature from 40 °C to 80 °C and a maximum hysteresis of 0.87% RH is found at a relative humidity of 80%. The sensitivity is also frequency dependent, increasing from 0.500 mV/% RH at 2 Hz to reach a maximum value of 1.634 mV/% RH at a frequency of 12 Hz, then decreasing to 1.110 mV/% RH at a frequency of 20 Hz. Finally, the CMOS-MEMS humidity sensor showed comparable response, recovery, and repeatability of measurements in three cycles as compared to a standard sensor that directly

  15. Fabrication and Characterization of a CMOS-MEMS Humidity Sensor.

    Science.gov (United States)

    Dennis, John-Ojur; Ahmed, Abdelaziz-Yousif; Khir, Mohd-Haris

    2015-07-10

    This paper reports on the fabrication and characterization of a Complementary Metal Oxide Semiconductor-Microelectromechanical System (CMOS-MEMS) device with embedded microheater operated at relatively elevated temperatures (40 °C to 80 °C) for the purpose of relative humidity measurement. The sensing principle is based on the change in amplitude of the device due to adsorption or desorption of humidity on the active material layer of titanium dioxide (TiO2) nanoparticles deposited on the moving plate, which results in changes in the mass of the device. The sensor has been designed and fabricated through a standard 0.35 µm CMOS process technology and post-CMOS micromachining technique has been successfully implemented to release the MEMS structures. The sensor is operated in the dynamic mode using electrothermal actuation and the output signal measured using a piezoresistive (PZR) sensor connected in a Wheatstone bridge circuit. The output voltage of the humidity sensor increases from 0.585 mV to 30.580 mV as the humidity increases from 35% RH to 95% RH. The output voltage is found to be linear from 0.585 mV to 3.250 mV as the humidity increased from 35% RH to 60% RH, with sensitivity of 0.107 mV/% RH; and again linear from 3.250 mV to 30.580 mV as the humidity level increases from 60% RH to 95% RH, with higher sensitivity of 0.781 mV/% RH. On the other hand, the sensitivity of the humidity sensor increases linearly from 0.102 mV/% RH to 0.501 mV/% RH with increase in the temperature from 40 °C to 80 °C and a maximum hysteresis of 0.87% RH is found at a relative humidity of 80%. The sensitivity is also frequency dependent, increasing from 0.500 mV/% RH at 2 Hz to reach a maximum value of 1.634 mV/% RH at a frequency of 12 Hz, then decreasing to 1.110 mV/% RH at a frequency of 20 Hz. Finally, the CMOS-MEMS humidity sensor showed comparable response, recovery, and repeatability of measurements in three cycles as compared to a standard sensor that directly

  16. Uncertainly Analysis of Two Types of Humidity Sensors by a Humidity Generator with a Divided-Flow System.

    Science.gov (United States)

    Chen, Ling-Hsi; Chen, Chiachung

    2018-02-21

    Humidity measurement is an important technique for the agricultural, foods, pharmaceuticals, and chemical industries. For the sake of convenience, electrical relative humidity (RH) sensors have been widely used. These sensors need to be calibrated to ensure their accuracy and the uncertainty measurement of these sensors has become a major concern. In this study, a self-made divided-flow generator was established to calibrate two types of electrical humidity sensors. The standard reference humidity was calculated from dew-point temperature and air dry-bulb temperature measured by a chilled mirror monitor. This divided-flow generator could produce consistent result of RH measurement results. The uncertainty of the reference standard increased with the increase of RH values. The combined uncertainty with the adequate calibration equations were ranged from 0.82% to 1.45% RH for resistive humidity sensors and 0.63% to 1.4% for capacitive humidity sensors, respectively. This self-made, divided-flow generator, and calibration method are cheap, time-saving, and easy to be used. Thus, the proposed approach can easily be applied in research laboratories.

  17. Uncertainly Analysis of Two Types of Humidity Sensors by a Humidity Generator with a Divided-Flow System

    Science.gov (United States)

    Chen, Ling-Hsi

    2018-01-01

    Humidity measurement is an important technique for the agricultural, foods, pharmaceuticals, and chemical industries. For the sake of convenience, electrical relative humidity (RH) sensors have been widely used. These sensors need to be calibrated to ensure their accuracy and the uncertainty measurement of these sensors has become a major concern. In this study, a self-made divided-flow generator was established to calibrate two types of electrical humidity sensors. The standard reference humidity was calculated from dew-point temperature and air dry-bulb temperature measured by a chilled mirror monitor. This divided-flow generator could produce consistent result of RH measurement results. The uncertainty of the reference standard increased with the increase of RH values. The combined uncertainty with the adequate calibration equations were ranged from 0.82% to 1.45% RH for resistive humidity sensors and 0.63% to 1.4% for capacitive humidity sensors, respectively. This self-made, divided-flow generator, and calibration method are cheap, time-saving, and easy to be used. Thus, the proposed approach can easily be applied in research laboratories. PMID:29466313

  18. NOAA Fundamental Climate Data Record (CDR) of AMSU-B and MHS Brightness Temperature, Version 1

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Climate Data Record (CDR) of Advanced Microwave Sounding Unit-B (AMSU-B) and Microwave Humidity Sounder (MHS) brightness temperature (Tb) in "window...

  19. Humidity dependence of adhesion for silane coated microcantilevers

    International Nuclear Information System (INIS)

    De Boer, Maarten P.; Mayer, Thomas M.; Carpick, Robert W.; Michalske, Terry A.; Srinivasan, U.; Maboudian, R.

    1999-01-01

    This study examines adhesion between silane-coated micromachined surfaces that are exposed to humid conditions. Our quantitative values for interfacial adhesion energies are determined from an in-situ optical measurement of deformations in partly-adhered cantilever beams. We coated micromachined cantilevers with either ODTS (C(sub 18)H(sub 37)SiCl(sub 3)) or FDTS (C(sub 8)F(sub 17)C(sub 2)H(sub 4)SiCl(sub 3)) with the objective of creating hydrophobic surfaces whose adhesion would be independent of humidity. In both cases, the adhesion energy is significantly lower than for uncoated, hydrophilic surfaces. For relative humidities (RH) less than 95% (ODTS) and 80% (FDTS) the adhesion energy was extremely low and constant. In fact, ODTS-coated beams exposed to saturated humidity conditions and long (48 hour) exposures showed only a factor of two increase in adhesion energy. Surprisingly, FDTS coated beams, which initially have a higher contact angle (115(degree)) with water than do ODTS coated beams (112(degree)), proved to be much more sensitive to humidity. The FDTS coated surfaces showed a factor of one hundred increase in adhesion energy after a seven hour exposure to 90% RH. Atomic force microscopy revealed agglomerated coating material after exposed to high RH, suggesting a redistribution of the monolayer film. This agglomeration was more prominent for FDTS than ODTS. These findings suggest a new mechanism for uptake of moisture under high humidity conditions. At high humidities, the silane coatings can reconfigure from a surface to a bulk phase leaving behind locally hydrophilic sites which increase the average measured adhesion energy. In order for the adhesion increase to be observed, a significant fraction of the monolayer must be converted from the surface to the bulk phase

  20. Influence of fine water droplets to temperature and humidity

    Science.gov (United States)

    Hafidzal, M. H. M.; Hamzah, A.; Manaf, M. Z. A.; Saadun, M. N. A.; Zakaria, M. S.; Roslizar, A.; Jumaidin, R.

    2015-05-01

    Excessively dry air can cause dry skin, dry eyes and exacerbation of medical conditions. Therefore, many researches have been done in order to increase humidity in our environment. One of the ways is by using water droplets. Nowadays, it is well known in market stand fan equipped with water mister in order to increase the humidity of certain area. In this study, the same concept is applied to the ceiling fan. This study uses a model that combines a humidifier which functions as cooler, ceiling fan and scaled down model of house. The objective of this study is to analyze the influence of ceiling fan humidifier to the temperature and humidity in a house. The mechanism of this small model uses batteries as the power source, connected to the fan and the humidifier. The small water tank's function is to store and supply water to the humidifier. The humidifier is used to cool the room by changing water phase to fine water droplets. Fine water droplets are created from mechanism of the humidifier, which is by increasing the kinetic energy of water molecule using high frequency vibration that overcome the holding force between water molecules. Thus, the molecule of water will change to state of gas or mist. The fan is used to spread out the mist of water to surrounding of the room in order to enhance the humidity. Thermocouple and humidity meter are used to measure temperature and humidity in some period of times. The result shows that humidity increases and temperature decreases with time. This application of water droplet can be applied in the vehicles and engine in order to decrease the temperature.

  1. Impacts of Climate Change on Dengue Risk in Brazil

    OpenAIRE

    Tatiane Menezes; Paula Pereda; Denisard Alves

    2014-01-01

    Climate has relevant impacts on human health. According to the World Health Organization (WHO), climate-sensitive health problems kill millions of people every year and undermine the physical and psychological health of millions (WHO, 2012). In the particular case of vector-borne diseases, climate conditions assure the vectors' survival and reproduction and, consequently, the transmission of the diseases (Kelly-Hope and Thomson, 2008). Increases in heat, precipitation, and humidity can allow ...

  2. A Black Swan and Sub-continental Scale Dynamics in Humid, Late-Holocene Broadleaf Forests

    Science.gov (United States)

    Pederson, N.; Dyer, J.; McEwan, R.; Hessl, A. E.; Mock, C. J.; Orwig, D.; Rieder, H. E.; Cook, B. I.

    2012-12-01

    In humid regions with dense broadleaf-dominated forests where gap-dynamics is the prevailing disturbance regime, paleoecological evidence shows regional-scale changes in forest composition associated with climatic change. To investigate the potential for regional events in late-Holocene forests, we use tree-ring data from 76 populations covering 840,000 km2 and 5.3k tree recruitment dates spanning 1.4 million km2 in the eastern US to investigate the occurrence of simultaneous forest dynamics across a humid region. We compare regional forest dynamics with an independent set of annually-resolved tree ring record of hydroclimate to examine whether climate dynamics might drive forest dynamics in this humid region. In forests where light availability is an important limitation for tree recruitment, we document a pulse of tree recruitment during the mid- to late-1600s across the eastern US. This pulse, which can be inferred as large-scale canopy opening, occurred during an era that multiple proxies indicate as extended drought between two intense pluvial. Principal component analysis of the 76 populations indicates a step-change increase in average ring width during the late-1770s resembling a potential canopy accession event over 42,800 km2 of the southeastern US. Growth-release analysis of populations loading strongly on this eigenvector indicates severe canopy disturbance from 1775-1779 that peaked in 1776. The 1776 event follows a period with extended droughts and severe large-scale frost event. We hypothesize these climatic events lead to elevated tree mortality in the late-1770s and canopy accession for understory trees. Superposed epoch analysis reveals that spikes of elevated canopy disturbance from 1685-1850 CE are significantly associated with drought. Extreme value theory statistics indicates the 1776 event lies beyond the 99.9 quantile and nearly 7 sigmas above the 1685-1850 mean rate of disturbance. The time-series of canopy disturbance from 1685-1850 is so

  3. A dual-biomarker approach for quantification of changes in relative humidity from sedimentary lipid D∕H ratios

    Directory of Open Access Journals (Sweden)

    O. Rach

    2017-07-01

    Full Text Available Past climatic change can be reconstructed from sedimentary archives by a number of proxies. However, few methods exist to directly estimate hydrological changes and even fewer result in quantitative data, impeding our understanding of the timing, magnitude and mechanisms of hydrological changes. Here we present a novel approach based on δ2H values of sedimentary lipid biomarkers in combination with plant physiological modeling to extract quantitative information on past changes in relative humidity. Our initial application to an annually laminated lacustrine sediment sequence from western Europe deposited during the Younger Dryas cold period revealed relative humidity changes of up to 15 % over sub-centennial timescales, leading to major ecosystem changes, in agreement with palynological data from the region. We show that by combining organic geochemical methods and mechanistic plant physiological models on well characterized lacustrine archives it is possible to extract quantitative ecohydrological parameters from sedimentary lipid biomarker δ2H data.

  4. The Climatology Module CLIMAT

    National Research Council Canada - National Science Library

    Avara, Elton

    1998-01-01

    ... (temperature, dew point temperature, absolute humidity, relative humidity, horizontal visibility, sea level pressure, wind speed, wind direction, cloudbase height, cloud cover, and Pasquill stability category...

  5. Opposing effects of humidity on rhodochrosite surface oxidation.

    Science.gov (United States)

    Na, Chongzheng; Tang, Yuanzhi; Wang, Haitao; Martin, Scot T

    2015-03-03

    Rhodochrosite (MnCO3) is a model mineral representing carbonate aerosol particles containing redox-active elements that can influence particle surface reconstruction in humid air, thereby affecting the heterogeneous transformation of important atmospheric constituents such as nitric oxides, sulfur dioxides, and organic acids. Using in situ atomic force microscopy, we show that the surface reconstruction of rhodochrosite in humid oxygen leads to the formation and growth of oxide nanostructures. The oxidative reconstruction consists of two consecutive processes with distinctive time scales, including a long waiting period corresponding to slow nucleation and a rapid expansion phase corresponding to fast growth. By varying the relative humidity from 55 to 78%, we further show that increasing humidity has opposing effects on the two processes, accelerating nucleation from 2.8(±0.2) × 10(-3) to 3.0(±0.2) × 10(-2) h(-1) but decelerating growth from 7.5(±0.3) × 10(-3) to 3.1(±0.1) × 10(-3) μm(2) h(-1). Through quantitative analysis, we propose that nanostructure nucleation is controlled by rhodochrosite surface dissolution, similar to the dissolution-precipitation mechanism proposed for carbonate mineral surface reconstruction in aqueous solution. To explain nanostructure growth in humid oxygen, a new Cabrera-Mott mechanism involving electron tunneling and solid-state diffusion is proposed.

  6. Effect of humidity on the filter pressure drop

    International Nuclear Information System (INIS)

    Vendel, J.; Letourneau, P.

    1995-01-01

    The effects of humidity on the filter pressure drop have been reported in some previous studies in which it is difficult to draw definite conclusions. These studies show contradictory effects of humidity on the pressure drop probably due to differences in the hygroscopicity of the test aerosols. The objective of this paper is to present experimental results on the evolution of the filter pressure drop versus mass loading, for different test aerosols and relative humidities. Present results are compared to those found in various publication. An experimental device has been designed to measure filter pressure drop as the function of the areal density for relative humidity varying in the range of 9 % to 85 %. Experiments have been conducted with hygroscopic: (CsOH) and nonhygroscopic aerosols (TiO 2 ). Cesium hydroxyde (CsOH) of size of 2 μ M AMMD has been generated by an ultrasonic generator and the 0.7 μm AMMD titanium oxyde has been dispersed by a open-quotes turn-tableclose quotes generator. As it is noted in the BISWAS'publication [3], present results show, in the case of nonhygroscopic aerosols, a linear relationship of pressure drop to mass loading. For hygroscopic aerosols two cases must be considered: for relative humidity below the deliquescent point of the aerosol, the relationship of pressure drop to mass loading remains linear; above the deliquescent point, the results show a sudden increase in the pressure drop and the mass capacity of the filter is drastically reduced

  7. Fabrication of Porous Silicon Based Humidity Sensing Elements on Paper

    Directory of Open Access Journals (Sweden)

    Tero Jalkanen

    2015-01-01

    Full Text Available A roll-to-roll compatible fabrication process of porous silicon (pSi based sensing elements for a real-time humidity monitoring is described. The sensing elements, consisting of printed interdigitated silver electrodes and a spray-coated pSi layer, were fabricated on a coated paper substrate by a two-step process. Capacitive and resistive responses of the sensing elements were examined under different concentrations of humidity. More than a three orders of magnitude reproducible decrease in resistance was measured when the relative humidity (RH was increased from 0% to 90%. A relatively fast recovery without the need of any refreshing methods was observed with a change in RH. Humidity background signal and hysteresis arising from the paper substrate were dependent on the thickness of sensing pSi layer. Hysteresis in most optimal sensing element setup (a thick pSi layer was still noticeable but not detrimental for the sensing. In addition to electrical characterization of sensing elements, thermal degradation and moisture adsorption properties of the paper substrate were examined in connection to the fabrication process of the silver electrodes and the moisture sensitivity of the paper. The results pave the way towards the development of low-cost humidity sensors which could be utilized, for example, in smart packaging applications or in smart cities to monitor the environment.

  8. Humidity-insensitive water evaporation from molecular complex fluids.

    Science.gov (United States)

    Salmon, Jean-Baptiste; Doumenc, Frédéric; Guerrier, Béatrice

    2017-09-01

    We investigated theoretically water evaporation from concentrated supramolecular mixtures, such as solutions of polymers or amphiphilic molecules, using numerical resolutions of a one-dimensional model based on mass transport equations. Solvent evaporation leads to the formation of a concentrated solute layer at the drying interface, which slows down evaporation in a long-time-scale regime. In this regime, often referred to as the falling rate period, evaporation is dominated by diffusive mass transport within the solution, as already known. However, we demonstrate that, in this regime, the rate of evaporation does not also depend on the ambient humidity for many molecular complex fluids. Using analytical solutions in some limiting cases, we first demonstrate that a sharp decrease of the water chemical activity at high solute concentration leads to evaporation rates which depend weakly on the humidity, as the solute concentration at the drying interface slightly depends on the humidity. However, we also show that a strong decrease of the mutual diffusion coefficient of the solution enhances considerably this effect, leading to nearly independent evaporation rates over a wide range of humidity. The decrease of the mutual diffusion coefficient indeed induces strong concentration gradients at the drying interface, which shield the concentration profiles from humidity variations, except in a very thin region close to the drying interface.

  9. Effect of humidity on the filter pressure drop

    Energy Technology Data Exchange (ETDEWEB)

    Vendel, J.; Letourneau, P. [Institut de Protection et de Surete Nucleaire, Gif-sur-Yvette (France)

    1995-02-01

    The effects of humidity on the filter pressure drop have been reported in some previous studies in which it is difficult to draw definite conclusions. These studies show contradictory effects of humidity on the pressure drop probably due to differences in the hygroscopicity of the test aerosols. The objective of this paper is to present experimental results on the evolution of the filter pressure drop versus mass loading, for different test aerosols and relative humidities. Present results are compared to those found in various publication. An experimental device has been designed to measure filter pressure drop as the function of the areal density for relative humidity varying in the range of 9 % to 85 %. Experiments have been conducted with hygroscopic: (CsOH) and nonhygroscopic aerosols (TiO{sub 2}). Cesium hydroxyde (CsOH) of size of 2 {mu} M AMMD has been generated by an ultrasonic generator and the 0.7 {mu}m AMMD titanium oxyde has been dispersed by a {open_quotes}turn-table{close_quotes} generator. As it is noted in the BISWAS`publication [3], present results show, in the case of nonhygroscopic aerosols, a linear relationship of pressure drop to mass loading. For hygroscopic aerosols two cases must be considered: for relative humidity below the deliquescent point of the aerosol, the relationship of pressure drop to mass loading remains linear; above the deliquescent point, the results show a sudden increase in the pressure drop and the mass capacity of the filter is drastically reduced.

  10. Performance limit of daytime radiative cooling in warm humid environment

    Directory of Open Access Journals (Sweden)

    Takahiro Suichi

    2018-05-01

    Full Text Available Daytime radiative cooling potentially offers efficient passive cooling, but the performance is naturally limited by the environment, such as the ambient temperature and humidity. Here, we investigate the performance limit of daytime radiative cooling under warm and humid conditions in Okayama, Japan. A cooling device, consisting of alternating layers of SiO2 and poly(methyl methacrylate on an Al mirror, is fabricated and characterized to demonstrate a high reflectance for sunlight and a selective thermal radiation in the mid-infrared region. In the temperature measurement under the sunlight irradiation, the device shows 3.4 °C cooler than a bare Al mirror, but 2.8 °C warmer than the ambient of 35 °C. The corresponding numerical analyses reveal that the atmospheric window in λ = 16 ∼ 25 μm is closed due to a high humidity, thereby limiting the net emission power of the device. Our study on the humidity influence on the cooling performance provides a general guide line of how one can achieve practical passive cooling in a warm humid environment.

  11. High-coercivity minerals from North African Humid Period soil material deposited in Lake Yoa (Chad)

    Science.gov (United States)

    Just, J.; Kroepelin, S.; Wennrich, V.; Viehberg, F. A.; Wagner, B.; Rethemeyer, J.; Karls, J.; Melles, M.

    2015-12-01

    The Holocene is a period of fundamental climatic change in North Africa. Humid conditions during the so-called African Humid Period (AHP) have favored the formation of big lake systems. Only very few of these lakes persist until today. One of them is Lake Yoa (19°03'N/20°31'E) in the Ounianga Basin, Chad, which maintains its water level by ground water inflow. Here we present the magnetic characteristics together with proxies for lacustrine productivity and biota of a sediment core (Co1240) from Lake Yoa, retrieved in 2010 within the framework of the Collaborative Research Centre 806 - Our Way to Europe (Deutsche Forschungsgemeinschaft). Magnetic properties of AHP sediments show strong indications for reductive diagenesis. An up to ~ 80 m higher lake level is documented by lacustrine deposits in the Ounianga Basin, dating to the early phase of the AHP. The higher lake level and less strong seasonality restricted deep mixing of the lake. Development of anoxic conditions consequently lead to the dissolution of iron oxides. An exception is an interval with high concentration of high-coercivity magnetic minerals, deposited between 7800 - 8120 cal yr BP. This interval post-dates the 8.2 event, which was dry in Northern Africa and probably caused a reduced vegetation cover. We propose that the latter resulted in the destabilization of soils around Lake Yoa. After the re-establishment of humid conditions, these soil materials were eroded and deposited in the lake. Magnetic minerals appear well preserved in the varved Late Holocene sequence, indicating (sub-) oxic conditions in the lake. This is surprising, because the occurrence of varves is often interpreted as an indicator for anoxic conditions of the lake water. However, the salinity of lake water rose strongly after the AHP. We therefore hypothesize that the conservation of varves and absence of benthic organisms rather relates to the high salinity than to anoxic conditions.

  12. Role of Temperature, Humidity and Rainfall on Influenza Transmission in Guatemala, El Salvador and Panama

    Science.gov (United States)

    Soebiyanto, Radina P.; Bonilla, Luis; Jara, Jorge; McCracken, John; Azziz?-Baumgartner, Eduardo; Widdowson, Marc-Alain; Kiang, Richard

    2012-01-01

    Worldwide, seasonal influenza causes about 500,000 deaths and 5 million severe illnesses per year. The environmental drivers of influenza transmission are poorly understood especially in the tropics. We aimed to identify meteorological factors for influenza transmission in tropical Central America. We gathered laboratory-confirmed influenza case-counts by week from Guatemala City, San Salvador Department (El Salvador) and Panama Province from 2006 to 2010. The average total cases per year were: 390 (Guatemala), 99 (San Salvador) and 129 (Panama). Meteorological factors including daily air temperature, rainfall, relative and absolute humidity (RH, AH) were obtained from ground stations, NASA satellites and land models. For these factors, we computed weekly averages and their deviation from the 5-yr means. We assessed the relationship between the number of influenza case-counts and the meteorological factors, including effects lagged by 1 to 4 weeks, using Poisson regression for each site. Our results showed influenza in San Salvador would increase by 1 case within a week of every 1 day with RH>75% (Relative Risk (RR)= 1.32, p=.001) and every 1C increase in minimum temperature (RR=1.29, p=.007) but it would decrease by 1 case for every 1mm-above mean weekly rainfall (RR=0.93,pGuatemala had 1 case increase for every 1C increase in minimum temperature in the previous week (RR=1.21, p<.001), and for every 1mm/day-above normal increase of rainfall rate (RR=1.03, p=.03) (model pseudo-R2=0.54). Our findings that cases increase with temperature and humidity differ from some temperate-zone studies. But they indicate that climate parameters such as humidity and temperature could be predictive of influenza activity and should be incorporated into country-specific influenza transmission models

  13. Effects of acute supplementation of Panax ginseng on endurance running in a hot & humid environment

    Science.gov (United States)

    Ping, Fadzel Wong Chee; Keong, Chen Chee; Bandyopadhyay, Amit

    2011-01-01

    Background & objectives: Athletes in Malaysia need to perform in a hot and humid environment due to the climatic nature of the country. c0 hronic supplementation of Panax ginseng (PG) (a deciduous perennial plant belonging to the Araliaceae family) enhances physical performance. As the ergogenic effect of acute supplementation of PG on endurance performance has not been explored in the Malaysian population especially in a hot and humid condition this study was taken up. Methods: Nine heat adapted recreational runners (age : 25.4 ± 6.9 yr, body mass : 57.6 ± 8.4 kg; body height : 168.3 ± 7.6 cm) were recruited in this placebo-controlled double-blind randomized study. Subjects ingested 200 mg of PG one hour before the exercise test on treadmill at 70 per cent of their VO2max in a laboratory environment of 31 °C and 70 per cent relative humidity. They drank 3 ml/kg body weight of cool water every 20 min during the exercise to prevent adverse effects of dehydration. Blood samples were drawn every 20 min for the analysis of glucose, lactate, insulin and free fatty acids. Oxygen uptake was determined every 20 min while heart rate, body and skin temperatures, and ratings of perceived exertion (RPE) were recorded every 10 min during the trials. Results: Endurance running time to exhaustion did not differ between PG and placebo trials. Heart rate, skin temperature, core body temperature, oxygen uptake, RPE, plasma insulin, glucose, free fatty acid and lactate levels during the endurance exercise did not show any significant differences between the trials. Interpretation & conclusions: We conclude that acute supplementation of 200 mg of PG did not affect the endurance running performance of the heat-adapted male recreational runners in the heat. PMID:21321426

  14. Seasonal trend analysis and ARIMA modeling of relative humidity and wind speed time series around Yamula Dam

    Science.gov (United States)

    Eymen, Abdurrahman; Köylü, Ümran

    2018-02-01

    Local climate change is determined by analysis of long-term recorded meteorological data. In the statistical analysis of the meteorological data, the Mann-Kendall rank test, which is one of the non-parametrical tests, has been used; on the other hand, for determining the power of the trend, Theil-Sen method has been used on the data obtained from 16 meteorological stations. The stations cover the provinces of Kayseri, Sivas, Yozgat, and Nevşehir in the Central Anatolia region of Turkey. Changes in land-use affect local climate. Dams are structures that cause major changes on the land. Yamula Dam is located 25 km northwest of Kayseri. The dam has huge water body which is approximately 85 km2. The mentioned tests have been used for detecting the presence of any positive or negative trend in meteorological data. The meteorological data in relation to the seasonal average, maximum, and minimum values of the relative humidity and seasonal average wind speed have been organized as time series and the tests have been conducted accordingly. As a result of these tests, the following have been identified: increase was observed in minimum relative humidity values in the spring, summer, and autumn seasons. As for the seasonal average wind speed, decrease was detected for nine stations in all seasons, whereas increase was observed in four stations. After the trend analysis, pre-dam mean relative humidity time series were modeled with Autoregressive Integrated Moving Averages (ARIMA) model which is statistical modeling tool. Post-dam relative humidity values were predicted by ARIMA models.

  15. Air humidity as key determinant of morphogenesis and productivity of the rare temperate woodland fern Polystichum braunii.

    Science.gov (United States)

    Schwerbrock, R; Leuschner, C

    2016-07-01

    (1) Most ferns are restricted to moist and shady habitats, but it is not known whether soil moisture or atmospheric water status are decisive limiting factors, or if both are equally important. (2) Using the rare temperate woodland fern Polystichum braunii, we conducted a three-factorial climate chamber experiment (soil moisture (SM) × air humidity (RH) × air temperature (T)) to test the hypotheses that: (i) atmospheric water status (RH) exerts a similarly large influence on the fern's biology as soil moisture, and (ii) both a reduction in RH and an increase in air temperature reduce vigour and growth. (3) Nine of 11 morphological, physiological and growth-related traits were significantly influenced by an increase in RH from 65% to 95%, leading to higher leaf conductance, increased above- and belowground productivity, higher fertility, more epidermal trichomes and fewer leaf deformities under high air humidity. In contrast, soil moisture variation (from 66% to 70% in the moist to ca. 42% in the dry treatment) influenced only one trait (specific leaf area), and temperature variation (15 °C versus 19 °C during daytime) only three traits (leaf conductance, root/shoot ratio, specific leaf area); RH was the only factor affecting productivity. (4) This study is the first experimental proof for a soil moisture-independent air humidity effect on the growth of terrestrial woodland ferns. P. braunii appears to be an air humidity hygrophyte that, whithin the range of realistic environmental conditions set in this study, suffers more from a reduction in RH than in soil moisture. A climate warming-related increase in summer temperatures, however, seems not to directly threaten this endangered species. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

  16. Humidity Testing of PME and BME Ceramic Capacitors with Cracks

    Science.gov (United States)

    Teverovsky, Alexander A.; Herzberger, Jaemi

    2014-01-01

    Cracks in ceramic capacitors are one of the major causes of failures during operation of electronic systems. Humidity testing has been successfully used for many years to verify the absence of cracks and assure quality of military grade capacitors. Traditionally, only precious metal electrode (PME) capacitors were used in high reliability applications and the existing requirements for humidity testing were developed for this type of parts. With the advance of base metal electrode (BME) capacitors, there is a need for assessment of the applicability of the existing techniques for the new technology capacitors. In this work, variety of different PME and BME capacitors with introduced cracks were tested in humid environments at different voltages and temperatures. Analysis of the test results indicates differences in the behavior and failure mechanisms for BME and PME capacitors and the need for different testing conditions.

  17. Humidity insensitive TOPAS polymer fiber Bragg grating sensor

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Khan, Lutul; Webb, David J.

    2011-01-01

    We report the first experimental demonstration of a humidity insensitive polymer optical fiber Bragg grating (FBG), as well as the first FBG recorded in a TOPAS polymer optical fiber in the important low loss 850nm spectral region. For the demonstration we have fabricated FBGs with resonance...... wavelength around 850 nm and 1550 nm in single-mode microstructured polymer optical fibers made of TOPAS and the conventional poly (methyl methacrylate) (PMMA). Characterization of the FBGs shows that the TOPAS FBG is more than 50 times less sensitive to humidity than the conventional PMMA FBG in both...... wavelength regimes. This makes the TOPAS FBG very appealing for sensing applications as it appears to solve the humidity sensitivity problem suffered by the PMMA FBG....

  18. Microwave Determination of Water Mole Fraction in Humid Gas Mixtures

    Science.gov (United States)

    Cuccaro, R.; Gavioso, R. M.; Benedetto, G.; Madonna Ripa, D.; Fernicola, V.; Guianvarc'h, C.

    2012-09-01

    A small volume (65 cm3) gold-plated quasi-spherical microwave resonator has been used to measure the water vapor mole fraction x w of H2O/N2 and H2O/air mixtures. This experimental technique exploits the high precision achievable in the determination of the cavity microwave resonance frequencies and is particularly sensitive to the presence of small concentrations of water vapor as a result of the high polarizability of this substance. The mixtures were prepared using the INRIM standard humidity generator for frost-point temperatures T fp in the range between 241 K and 270 K and a commercial two-pressure humidity generator operated at a dew-point temperature between 272 K and 291 K. The experimental measurements compare favorably with the calculated molar fractions of the mixture supplied by the humidity generators, showing a normalized error lower than 0.8.

  19. Effects of air humidity on ionization chamber response

    International Nuclear Information System (INIS)

    Meger, C.; DeLuca, P.M. Jr.; Pearson, D.W.; Venci, R.

    1983-01-01

    A study of the effect of air humidity on four different ionization chamber cap materials verified earlier studies (Kristensen and Sundbom, 1981; Mijnheer et al., 1983) and extended our understanding of the problem. We found nylon and A-150 plastic caps swell as they absorb water from the air. This accounts for as much as 2.5% increase in ionization response. Graphite chambers readily absorb and desorb water from the air. This creates a problem in maintaining dry air in a wet graphite chamber. Humid air has a different density and W value than dry air (Niatel, 1969, 1975). This decreases the charge collected in a wet graphite chamber. We observe a decrease in response of approximately 2%, a value greater than can be accounted for by these effects alone. Polyethylene chambers are unaffected by humid air. 4 refs., 9 figs

  20. Humidity Data for 9975 Shipping Packages with Softwood Fiberboard

    Energy Technology Data Exchange (ETDEWEB)

    Daugherty, W. L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-01-12

    The 9975 surveillance program is developing a technical basis to support extending the storage period of 9975 packages in K-Area Complex beyond the currently approved 15 years. A key element of this effort is developing a better understanding of degradation of the fiberboard assembly under storage conditions. This degradation is influenced greatly by the moisture content of the fiberboard, which is not well characterized on an individual package basis. Direct measurements of humidity and fiberboard moisture content have been made on two test packages with softwood fiberboard and varying internal heat levels from 0 up to 19W. Comparable measurements with cane fiberboard have been reported previously. With an internal heat load, a temperature gradient in the fiberboard assembly leads to varying relative humidity in the air around the fiberboard. However, the absolute humidity tends to remain approximately constant throughout the package, especially at lower heat loads.

  1. Low-cost personal cooling in hot humid offices. Feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Gunnarsen, L [Danish Building Research Inst., (Denmark); Santos, A [Univ. of the Philippines, Diliman (Philippines)

    1997-05-01

    A solution, based on low-cost solar-powered air drying, to heat stress in buildings located in developing countries with a hot and humid climate is presented. The air-drying facilities are described and a validation of the ensuing benefits through comprehensive human exposure studies is given. A prototype of a solar powered supply system for dried air was constructed and supply air was led to six personal units for ventilation and cooling placed in cubicles simulating office workplaces. 123 heat-acclimatized people were exposed for one hour in each of the cubicles. It is concluded that drying indoor air reduces heat stress among heat-adapted people in hot and humid offices and that the low-cost solar powered air drying system functioned satisfactorily , although some improvements are recommended. The drying power of the sun can be stored in recovered silica gel beads and used for other purposes. It is suggested that further research could explore the possibility of desiccant drying of agricultural products during the rainy season. (ARW) 30 refs.

  2. Application of graphene oxide based Microfiber-Knot resonator for relative humidity sensing

    Directory of Open Access Journals (Sweden)

    S.R. Azzuhri

    2018-06-01

    Full Text Available A relative humidity (RH sensor is proposed and demonstrated using a micro-knot resonator (MKR enhanced with a layer graphene oxide (GO coating. The MKR is fabricated by means of tapering a standard fiber, with the GO coating added by the drop-cast method. The proposed sensor is tested for an RH range of between 0% and 80% at 20% intervals, and the configurations with and without the GO coating achieve sensitivities of 0.0104 nm/% and 0.0095 nm/%, respectively. The MKR configuration without the GO coating has a linear response correlation coefficient of 0.9098 and a resolution of 0.1%, while the configuration with the GO coating has a linear response correlation coefficient of 0.9548 and a resolution of 0.096% which is better. The proposed sensor has multiple applications, especially in the area of climate and atmospheric measurement and monitoring. Keywords: Microfiber, Resonator, Humidity sensor

  3. Evaporation Kinetics of Laboratory Generated Secondary Organic Aerosols at Elevated Relative Humidity

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Jacqueline M.; Imre, D.; Beranek, Josef; Shrivastava, ManishKumar B.; Zelenyuk, Alla

    2015-01-06

    Secondary organic aerosols (SOA) dominate atmospheric organic aerosols that affect climate, air quality, and health. Recent studies indicate that, contrary to previously held assumptions, at low relative humidity (RH) these particles are semi-solid and evaporate orders of magnitude slower than expected. Elevated relative humidity has the potential to affect significantly formation, properties, and atmospheric evolution of SOA particles. Here we present a study of the effect of RH on the room-temperature evaporation kinetics of SOA particles formed by ozonolysis of α-pinene and limonene. Experiments were carried out on SOA particles generated, evaporated, and aged at 0%, 50% and 90% RH. We find that in all cases evaporation begins with a relatively fast phase, during which 30% to 70% of the particle mass evaporates in 2 hours, followed by a much slower evaporation rate. Evaporation kinetics at 0% and 50% RH are nearly the same, while at 90% RH a slightly larger fraction evaporates. In all cases, aging the particles prior to inducing evaporation reduces the evaporative losses, with aging at elevated RH leading to more significant effect. In all cases, SOA evaporation is nearly size-independent, providing direct evidence that oligomers play a crucial role in determining the evaporation kinetics.

  4. The potential of a modified physiologically equivalent temperature (mPET) based on local thermal comfort perception in hot and humid regions

    Science.gov (United States)

    Lin, Tzu-Ping; Yang, Shing-Ru; Chen, Yung-Chang; Matzarakis, Andreas

    2018-02-01

    Physiologically equivalent temperature (PET) is a thermal index that is widely used in the field of human biometeorology and urban bioclimate. However, it has several limitations, including its poor ability to predict thermo-physiological parameters and its weak response to both clothing insulation and humid conditions. A modified PET (mPET) was therefore developed to address these shortcomings. To determine whether the application of mPET in hot-humid regions is more appropriate than the PET, an analysis of a thermal comfort survey database, containing 2071 questionnaires collected from participants in hot-humid Taiwan, was conducted. The results indicate that the thermal comfort range is similar (26-30 °C) when the mPET and PET are applied as thermal indices to the database. The sensitivity test for vapor pressure and clothing insulation also show that the mPET responds well to the behavior and perceptions of local people in a subtropical climate.

  5. Nature Relation Between Climatic Variables and Cotton Production

    Directory of Open Access Journals (Sweden)

    Zakaria M. Sawan

    2014-08-01

    Full Text Available This study investigated the effect of climatic variables on flower and boll production and retention in cotton (Gossypium barbadense. Also, this study investigated the relationship between climatic factors and production of flowers and bolls obtained during the development periods of the flowering and boll stage, and to determine the most representative period corresponding to the overall crop pattern. Evaporation, sunshine duration, relative humidity, surface soil temperature at 1800 h, and maximum air temperature, are the important climatic factors that significantly affect flower and boll production. The least important variables were found to be surface soil temperature at 0600 h and minimum temperature. There was a negative correlation between flower and boll production and either evaporation or sunshine duration, while that correlation with minimum relative humidity was positive. Higher minimum relative humidity, short period of sunshine duration, and low temperatures enhanced flower and boll formation.

  6. Climate Change

    Science.gov (United States)

    Climate is the average weather in a place over a period of time. Climate change is major change in temperature, rainfall, snow, ... by natural factors or by human activities. Today climate changes are occurring at an increasingly rapid rate. ...

  7. Agriculture: Climate

    Science.gov (United States)

    Climate change affects agricultural producers because agriculture and fisheries depend on specific climate conditions. Temperature changes can cause crop planting dates to shift. Droughts and floods due to climate change may hinder farming practices.

  8. Amplification of wildfire area burnt by hydrological drought in the humid tropics

    Science.gov (United States)

    Taufik, Muh; Torfs, Paul J. J. F.; Uijlenhoet, Remko; Jones, Philip D.; Murdiyarso, Daniel; van Lanen, Henny A. J.

    2017-06-01

    Borneo's diverse ecosystems, which are typical humid tropical conditions, are deteriorating rapidly, as the area is experiencing recurrent large-scale wildfires, affecting atmospheric composition and influencing regional climate processes. Studies suggest that climate-driven drought regulates wildfires, but these overlook subsurface processes leading to hydrological drought, an important driver. Here, we show that models which include hydrological processes better predict area burnt than those solely based on climate data. We report that the Borneo landscape has experienced a substantial hydrological drying trend since the early twentieth century, leading to progressive tree mortality, more severe than in other tropical regions. This has caused massive wildfires in lowland Borneo during the past two decades, which we show are clustered in years with large areas of hydrological drought coinciding with strong El Niño events. Statistical modelling evidence shows amplifying wildfires and greater area burnt in response to El Niño/Southern Oscillation (ENSO) strength, when hydrology is considered. These results highlight the importance of considering hydrological drought for wildfire prediction, and we recommend that hydrology should be considered in future studies of the impact of projected ENSO strength, including effects on tropical ecosystems, and biodiversity conservation.

  9. Humidity data for 9975 shipping packages with cane fiberboard

    Energy Technology Data Exchange (ETDEWEB)

    Daugherty, W. L. [Savannah River Site (SRS), Aiken, SC (United States)

    2016-05-01

    The 9975 surveillance program is developing a technical basis to support extending the storage period of 9975 packages in K-Area Complex beyond the currently approved 15 years. A key element of this effort is developing a better understanding of degradation of the fiberboard assembly under storage conditions. This degradation is influenced greatly by the moisture content of the fiberboard, which is not well characterized on an individual package basis. Direct measurements of humidity and fiberboard moisture content have been made on two test packages with cane fiberboard and varying internal heat levels from 0 up to 19W. With an internal heat load, a temperature gradient in the fiberboard assembly leads to varying relative humidity in the air around the fiberboard. However, the absolute humidity tends to remain approximately constant throughout the package. The moisture content of fiberboard varies under the influence of several phenomena. Changes in local fiberboard temperature (from an internal heat load) can cause fiberboard moisture changes through absorption or evaporation. Fiberboard degradation at elevated temperature will produce water as a byproduct. And the moisture level within the package is constantly seeking equilibrium with that of the surrounding room air, which varies on a daily and seasonal basis. One indicator of the moisture condition within a 9975 package might be obtained by measuring the relative humidity in the upper air space, by inserting a humidity probe through a caplug hole. However, the data indicate that for the higher internal heat loads (15 and 19 watts), a large variation in internal moisture conditions produces little or no variation in the air space relative humidity. Therefore, this approach does not appear to be sensitive to fiberboard moisture variations at the higher heat loads which are of most interest to maintaining fiberboard integrity.

  10. Humidity Responsive Photonic Sensor based on a Carboxymethyl Cellulose Mechanical Actuator

    OpenAIRE

    Hartings, Matthew; Douglass, Kevin O.; Neice, Claire; Ahmed, Zeeshan

    2017-01-01

    We describe an intuitive and simple method for exploiting humidity-driven volume changes in carboxymethyl cellulose (CMC) to fabricate a humidity responsive actuator on a glass fiber substrate. We optimize this platform to generate a photonic-based humidity sensor where CMC coated on a fiber optic containing a fiber Bragg grating (FBG) actuates a mechanical strain in response to humidity changes. The humidity-driven mechanical deformation of the FBG results in a large lin...

  11. Fiber optic humidity sensor using water vapor condensation.

    Science.gov (United States)

    Limodehi, Hamid E; Légaré, François

    2017-06-26

    The rate of vapor condensation on a solid surface depends on the ambient relative humidity (RH). Also, surface plasmon resonance (SPR) on a metal layer is sensitive to the refractive index change of its adjacent dielectric. The SPR effect appears as soon as a small amount of moisture forms on the sensor, resulting in a decrease in the amount of light transmitted due to plasmonic loss. Using this concept, we developed a fiber optic humidity sensor based on SPR. It can measure the ambient RH over a dynamic range from 10% to 85% with an accuracy of 3%.

  12. Influence of Temperature and Humidity on Bakelite Resistivity

    CERN Document Server

    Arnaldi, R; Barret, V; Bastid, N; Blanchard, G; Chiavassa, E; Cortese, P; Crochet, Philippe; Dellacasa, G; De Marco, N; Dupieux, P; Espagnon, B; Fargeix, J; Ferretti, A; Gallio, M; Lamoine, L; Luquin, Lionel; Manso, F; Mereu, P; Métivier, V; Musso, A; Oppedisano, C; Piccotti, A; Rahmani, A; Royer, L; Roig, O; Scalas, E; Scomparin, E; Vercellin, Ermanno

    1999-01-01

    Presentation made at RPC99 and submitted to Elsevier PreprintThe use of phenolic or melaminic bakelite as RPC electrodes is widespread. The electrode resistivity is an important parameter for the RPC performance. As recent studies have pointed out, the bakelite resistivity changes with temperature and is influenced by humidity. In order to gain a quantitative understanding on the influence of temperature and humidity on RPC electrodes, we assembled an apparatus to measure resistivity in well-controlled conditions. A detailed description of the experimental set-up as well as the first resistivity measurements for various laminates in different environmental conditions are presented.

  13. Ground calibration of DREAMS-H relative humidity device

    Science.gov (United States)

    Komu, M.; Genzer, M.; Nikkanen, T.; Schmidt, W.; Haukka, H.; Kemppinen, O.; Harri, A.-M.

    2014-04-01

    DREAMS (Dust Characterization, Risk Assessment and Environmental Analyzer on the Martian Surface) instrument suite is to be launched as part of ESA ExoMars 2016/Entry, Descent and Landing Demonstration Module (EDM). DREAMS consists of an environmental package for monitoring temperature, pressure, relative humidity, winds and dust opacity, as well as atmospheric electricity of Martian atmosphere. DREAMS instruments and scientific goals are described in [1]. Here we describe ground calibration of the relative humidity device, DREAMS-H, provided to DREAMS payload by Finnish Meteorological Institute and based on proprietary technology of Vaisala, Inc. Same kind of device is part of REMS instrument package onboard MSL Curiosity Rover [2][3].

  14. Modelling approach for the rainfall erosivity index in sub-humid urban areas in northern Algeria

    Science.gov (United States)

    Touaibia, I.; Abderrahmane Guenim, N.; Touaibia, B.

    2014-09-01

    This work presents an approach for storm water erosivity index modelling in the absence of measurement in an urban area, in a sub-humid climate. In torrential storms, floods, loaded with sediments, obstruct storm water drainage. With the aim of estimating the amount of sediment that can be deposited on a stretch of road, adjacent to the study area, the erosivity index is determined from a count of 744 rain showers recorded over a period of 19 years. The Universal Soil Loss Equation (USLE) of Wischmeier and Smith is applied, where only the index of erosivity is calculated; it is based on the intensity of the rain starting the process of erosion in the basin. Functional relations are required between this factor and the explanatory variables. A power type regression model is reached, making it possible to bring a decision-making aid in absences of measurements.

  15. Modelling approach for the rainfall erosivity index in sub-humid urban areas in northern Algeria

    Directory of Open Access Journals (Sweden)

    I. Touaibia

    2014-09-01

    Full Text Available This work presents an approach for storm water erosivity index modelling in the absence of measurement in an urban area, in a sub-humid climate. In torrential storms, floods, loaded with sediments, obstruct storm water drainage. With the aim of estimating the amount of sediment that can be deposited on a stretch of road, adjacent to the study area, the erosivity index is determined from a count of 744 rain showers recorded over a period of 19 years. The Universal Soil Loss Equation (USLE of Wischmeier and Smith is applied, where only the index of erosivity is calculated; it is based on the intensity of the rain starting the process of erosion in the basin. Functional relations are required between this factor and the explanatory variables. A power type regression model is reached, making it possible to bring a decision-making aid in absences of measurements.

  16. Selection of climate change scenario data for impact modelling

    DEFF Research Database (Denmark)

    Sloth Madsen, M; Fox Maule, C; MacKellar, N

    2012-01-01

    Impact models investigating climate change effects on food safety often need detailed climate data. The aim of this study was to select climate change projection data for selected crop phenology and mycotoxin impact models. Using the ENSEMBLES database of climate model output, this study...... illustrates how the projected climate change signal of important variables as temperature, precipitation and relative humidity depends on the choice of the climate model. Using climate change projections from at least two different climate models is recommended to account for model uncertainty. To make...... the climate projections suitable for impact analysis at the local scale a weather generator approach was adopted. As the weather generator did not treat all the necessary variables, an ad-hoc statistical method was developed to synthesise realistic values of missing variables. The method is presented...

  17. Two types of physical inconsistency to avoid with quantile mapping: a case study with relative humidity over North America.

    Science.gov (United States)

    Grenier, P.

    2017-12-01

    Statistical post-processing techniques aim at generating plausible climate scenarios from climate simulations and observation-based reference products. These techniques are generally not physically-based, and consequently they remedy the problem of simulation biases at the risk of generating physical inconsistency (PI). Although this concern is often emphasized, it is rarely addressed quantitatively. Here, PI generated by quantile mapping (QM), a technique widely used in climatological and hydrological applications, is investigated using relative humidity (RH) and its parent variables, namely specific humidity (SH), temperature and pressure. PI is classified into two types: 1) inadequate value for an individual variable (e.g. RH > 100 %), and 2) breaking of an inter-variable relationship. Scenarios built for this study correspond to twelve sites representing a variety of climate types over North America. Data used are an ensemble of ten 3-hourly global (CMIP5) and regional (CORDEX-NAM) simulations, as well as the CFSR reanalysis. PI of type 1 is discussed in terms of frequency of occurrence and amplitude of unphysical cases for RH and SH variables. PI of type 2 is investigated with heuristic proxies designed to directly compare the physical inconsistency problem with the initial bias problem. Finally, recommendations are provided for an appropriate use of QM given the potential to generate physical inconsistency of types 1 and 2.

  18. Temperature-dependent deliquescence relative humidities and water activities using humidity controlled thermogravimetric analysis with application to malonic acid.

    Science.gov (United States)

    Beyer, Keith D; Schroeder, Jason R; Kissinger, Jared A

    2014-04-03

    We utilize a new experimental technique, humidity-controlled thermogravimetric analysis (HTGA), to determine temperature-dependent deliquescence relative humidities (DRH) and to determine the equilibrium concentration of a solution at a given temperature and relative humidity. To that end, we have investigated the malonic acid/water system determining the DRH and concentration/RH relationship in the temperature range 303-278 K. Excellent agreement is found with literature values for the DRH of malonic acid as a function of temperature and for the concentration/RH relationship at several temperatures. Thus, we extend the DRH and concentration/RH relationship to a broader temperature range and are using the HTGA experiments to investigate other organic acids.

  19. Forests growing under dry conditions have higher hydrological resilience to drought than do more humid forests.

    Science.gov (United States)

    Helman, David; Lensky, Itamar M; Yakir, Dan; Osem, Yagil

    2017-07-01

    More frequent and intense droughts are projected during the next century, potentially changing the hydrological balances in many forested catchments. Although the impacts of droughts on forest functionality have been vastly studied, little attention has been given to studying the effect of droughts on forest hydrology. Here, we use the Budyko framework and two recently introduced Budyko metrics (deviation and elasticity) to study the changes in the water yields (rainfall minus evapotranspiration) of forested catchments following a climatic drought (2006-2010) in pine forests distributed along a rainfall gradient (P = 280-820 mm yr -1 ) in the Eastern Mediterranean (aridity factor = 0.17-0.56). We use a satellite-based model and meteorological information to calculate the Budyko metrics. The relative water yield ranged from 48% to 8% (from the rainfall) in humid to dry forests and was mainly associated with rainfall amount (increasing with increased rainfall amount) and bedrock type (higher on hard bedrocks). Forest elasticity was larger in forests growing under drier conditions, implying that drier forests have more predictable responses to drought, according to the Budyko framework, compared to forests growing under more humid conditions. In this context, younger forests were shown more elastic than older forests. Dynamic deviation, which is defined as the water yield departure from the Budyko curve, was positive in all forests (i.e., less-than-expected water yields according to Budyko's curve), increasing with drought severity, suggesting lower hydrological resistance to drought in forests suffering from larger rainfall reductions. However, the dynamic deviation significantly decreased in forests that experienced relatively cooler conditions during the drought period. Our results suggest that forests growing under permanent dry conditions might develop a range of hydrological and eco-physiological adjustments to drought leading to higher hydrological

  20. Orographic cirrus in a future climate

    Directory of Open Access Journals (Sweden)

    H. Joos

    2009-10-01

    Full Text Available A cloud resolving model (CRM is used to investigate the formation of orographic cirrus clouds in the current and future climate. The formation of cirrus clouds depends on a variety of dynamical and thermodynamical processes, which act on different scales. First, the capability of the CRM in realistically simulating orographic cirrus clouds has been tested by comparing the simulated results to aircraft measurements of an orographic cirrus cloud. The influence of a warmer climate on the microphysical and optical properties of cirrus clouds has been investigated by initializing the CRM with vertical profiles of horizontal wind, potential temperature and equivalent potential temperature, respectively. The vertical profiles are extracted from IPCC A1B simulations for the current climate and for the period 2090–2099 for two regions representative for North and South America. The influence of additional moisture in a future climate on the propagation of gravity waves and the formation of orographic cirrus could be estimated. In a future climate, the increase in moisture dampens the vertical propagation of gravity waves and the occurring vertical velocities in the moist simulations. Together with higher temperatures fewer ice crystals nucleate homogeneously. Assuming that the relative humidity does not change in a warmer climate the specific humidity in the model is increased. This increase in specific humidity in a warmer climate results in a higher ice water content. The net effect of a reduced ice crystal number concentration and a higher ice water content is an increased optical depth. However, in some moist simulations dynamical changes contribute to changes in the ice water content, ice crystal number concentration and optical depth. For the corresponding dry simulations dynamical changes are more pronounced leading to a decreased optical depth in a future climate in some cases.

  1. Response of the North Atlantic surface and intermediate ocean structure to climate warming of MIS 11.

    Science.gov (United States)

    Kandiano, Evgenia S; van der Meer, Marcel T J; Schouten, Stefan; Fahl, Kirsten; Sinninghe Damsté, Jaap S; Bauch, Henning A

    2017-04-10

    Investigating past interglacial climates not only help to understand how the climate system operates in general, it also forms a vital basis for climate predictions. We reconstructed vertical stratification changes in temperature and salinity in the North Atlantic for a period some 400 ka ago (MIS11), an interglacial time analogue of a future climate. As inferred from a unique set of biogeochemical, geochemical, and faunal data, the internal upper ocean stratification across MIS 11 shows distinct depth-dependent dynamical changes related to vertical as well as lateral shifts in the upper Atlantic meridional circulation system. Importantly, transient cold events are recognized near the end of the long phase of postglacial warming at surface, subsurface, mid, and deeper water layers. These data demonstrate that MIS 11 coolings over the North Atlantic were initially triggered by freshwater input at the surface and expansion of cold polar waters into the Subpolar Gyre. The cooling signal was then transmitted downwards into mid-water depths. Since the cold events occurred after the main deglacial phase we suggest that their cause might be related to continuous melting of the Greenland ice sheet, a mechanism that might also be relevant for the present and upcoming climate.

  2. Biases of the MET Temperature and Relative Humidity Sensor (HMP45) Report

    Energy Technology Data Exchange (ETDEWEB)

    Kyrouac, Jenni [Argonne National Lab. (ANL), Argonne, IL (United States); Theisen, Adam [Univ. of Oklahoma, Norman, OK (United States)

    2017-06-30

    The U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility Data Quality (DQ) Office was alerted to a potential bias in the surface meteorological instrumentation (MET) temperature when compared with a nearby Mesonet station. This led to an investigation into this problem that was expanded to include many of the other extended facilities (EF) and both the temperature and relative humidity (RH) variables. For this study, the Mesonet was used as the standard reference due to results that showed an increased accuracy in high-humidity environments along with the fact that the Mesonet had previous documented a problem with the HMP45C sensors. Some differences between the sites were taken into account during the analysis: 1. ARM MET sensors were upgraded from an HMP35 to an HMP45 throughout 2007 2. Mesonet switched to aspirated shields in 2009 – To mitigate the differences between aspirated and non-aspirated measurements, data were only analyzed when the wind speed was higher than 3 m/s. This reduced the uncertainty for the non-aspirated measurements from 1.51 ºC to 0.4 ºC. 3. ARM MET is mounted 0.5m higher than the Mesonet station (2.0m versus 1.5m) – This is assumed to have a negligible effect on the differences. 4. Sites were not co-located – For some locations, the distances between sites were as much as 45 km. As part of the investigation into the differences, the Mesonet had reported that the HMP45 sensors had a low-temperature bias in high-humidity environments. This was verified at two different sites where the ARM measurements were compared with the Mesonet measurements. The Mesonet provided redundant temperature measurements from two different sensors at each site. These measurements compared fairly well, while the ARM sensor showed a bias overnight when the humidities were higher. After reviewing the yearly average differences in the data and analyzing the RH data during fog events when we assume it should be

  3. Heat and Humidity in the City: Neighborhood Heat Index Variability in a Mid-Sized City in the Southeastern United States.

    Science.gov (United States)

    Hass, Alisa L; Ellis, Kelsey N; Reyes Mason, Lisa; Hathaway, Jon M; Howe, David A

    2016-01-11

    Daily weather conditions for an entire city are usually represented by a single weather station, often located at a nearby airport. This resolution of atmospheric data fails to recognize the microscale climatic variability associated with land use decisions across and within urban neighborhoods. This study uses heat index, a measure of the combined effects of temperature and humidity, to assess the variability of heat exposure from ten weather stations across four urban neighborhoods and two control locations (downtown and in a nearby nature center) in Knoxville, Tennessee, USA. Results suggest that trees may negate a portion of excess urban heat, but are also associated with greater humidity. As a result, the heat index of locations with more trees is significantly higher than downtown and areas with fewer trees. Trees may also reduce heat stress by shading individuals from incoming radiation, though this is not considered in this study. Greater amounts of impervious surfaces correspond with reduced evapotranspiration and greater runoff, in terms of overall mass balance, leading to a higher temperature, but lower relative humidity. Heat index and relative humidity were found to significantly vary between locations with different tree cover and neighborhood characteristics for the full study time period as well as for the top 10% of heat index days. This work demonstrates the need for high-resolution climate data and the use of additional measures beyond temperature to understand urban neighborhood exposure to extreme heat, and expresses the importance of considering vulnerability differences among residents when analyzing neighborhood-scale impacts.

  4. Humidity affects the performance of von Frey monofilaments

    DEFF Research Database (Denmark)

    Werner, M U; Nielsen, Per Rotbøll; Ellehuus-Hilmersson, C

    2011-01-01

    Assessment of tactile and nociceptive thresholds of the skin with calibrated polyamide monofilaments is an established testing method both in animal and in human research. It is known that changes in relative humidity may affect the physical properties of the monofilaments. As this effect has onl...

  5. Small-scale variability in tropical tropopause layer humidity

    Science.gov (United States)

    Jensen, E. J.; Ueyama, R.; Pfister, L.; Karcher, B.; Podglajen, A.; Diskin, G. S.; DiGangi, J. P.; Thornberry, T. D.; Rollins, A. W.; Bui, T. V.; Woods, S.; Lawson, P.

    2016-12-01

    Recent advances in statistical parameterizations of cirrus cloud processes for use in global models are highlighting the need for information about small-scale fluctuations in upper tropospheric humidity and the physical processes that control the humidity variability. To address these issues, we have analyzed high-resolution airborne water vapor measurements obtained in the Airborne Tropical TRopopause EXperiment over the tropical Pacific between 14 and 20 km. Using accurate and precise 1-Hz water vapor measurements along approximately-level aircraft flight legs, we calculate structure functions spanning horizontal scales ranging from about 0.2 to 50 km, and we compare the water vapor variability in the lower (about 14 km) and upper (16-19 km) Tropical Tropopause Layer (TTL). We also compare the magnitudes and scales of variability inside TTL cirrus versus in clear-sky regions. The measurements show that in the upper TTL, water vapor concentration variance is stronger inside cirrus than in clear-sky regions. Using simulations of TTL cirrus formation, we show that small variability in clear-sky humidity is amplified by the strong sensitivity of ice nucleation rate to supersaturation, which results in highly-structured clouds that subsequently drive variability in the water vapor field. In the lower TTL, humidity variability is correlated with recent detrainment from deep convection. The structure functions indicate approximately power-law scaling with spectral slopes ranging from about -5/3 to -2.

  6. Humidity Sensors Principle, Mechanism, and Fabrication Technologies: A Comprehensive Review

    Science.gov (United States)

    Farahani, Hamid; Wagiran, Rahman; Hamidon, Mohd Nizar

    2014-01-01

    Humidity measurement is one of the most significant issues in various areas of applications such as instrumentation, automated systems, agriculture, climatology and GIS. Numerous sorts of humidity sensors fabricated and developed for industrial and laboratory applications are reviewed and presented in this article. The survey frequently concentrates on the RH sensors based upon their organic and inorganic functional materials, e.g., porous ceramics (semiconductors), polymers, ceramic/polymer and electrolytes, as well as conduction mechanism and fabrication technologies. A significant aim of this review is to provide a distinct categorization pursuant to state of the art humidity sensor types, principles of work, sensing substances, transduction mechanisms, and production technologies. Furthermore, performance characteristics of the different humidity sensors such as electrical and statistical data will be detailed and gives an added value to the report. By comparison of overall prospects of the sensors it was revealed that there are still drawbacks as to efficiency of sensing elements and conduction values. The flexibility offered by thick film and thin film processes either in the preparation of materials or in the choice of shape and size of the sensor structure provides advantages over other technologies. These ceramic sensors show faster response than other types. PMID:24784036

  7. Hydration behaviour of synthetic saponite at variable relative humidity

    Indian Academy of Sciences (India)

    Hydration behaviour of synthetic saponite was examined by X-ray powder diffraction simulation at various relative humidities (RH). The basal spacing of the Ca-saponite increased stepwise with increase in RH. The (00) reflections observed reflect single or dual hydration states of smectite. Quasi-rational, intermediate, or ...

  8. Effects of relative humidity on banana fruit drop

    NARCIS (Netherlands)

    Saengpook, C.; Ketsa, S.; Doorn, van W.G.

    2007-01-01

    Commercial ripening of banana fruit occurs at high relative humidity (RH), which prevents browning of damaged skin areas. In experiments with ripening at high RH (94 ± 1%) the individual fruit (fingers) of `Sucrier¿ (Musa acuminata, AA Group) banana exhibited a high rate of drop. The falling off of

  9. A method for high accuracy determination of equilibrium relative humidity

    DEFF Research Database (Denmark)

    Jensen, O.M.

    2012-01-01

    This paper treats a new method for measuring equilibrium relative humidity and equilibrium dew-point temperature of a material sample. The developed measuring device is described – a Dew-point Meter – which by means of so-called Dynamic Dew-point Analysis permits quick and very accurate...

  10. Humidity Sensors Principle, Mechanism, and Fabrication Technologies: A Comprehensive Review

    Directory of Open Access Journals (Sweden)

    Hamid Farahani

    2014-04-01

    Full Text Available Humidity measurement is one of the most significant issues in various areas of applications such as instrumentation, automated systems, agriculture, climatology and GIS. Numerous sorts of humidity sensors fabricated and developed for industrial and laboratory applications are reviewed and presented in this article. The survey frequently concentrates on the RH sensors based upon their organic and inorganic functional materials, e.g., porous ceramics (semiconductors, polymers, ceramic/polymer and electrolytes, as well as conduction mechanism and fabrication technologies. A significant aim of this review is to provide a distinct categorization pursuant to state of the art humidity sensor types, principles of work, sensing substances, transduction mechanisms, and production technologies. Furthermore, performance characteristics of the different humidity sensors such as electrical and statistical data will be detailed and gives an added value to the report. By comparison of overall prospects of the sensors it was revealed that there are still drawbacks as to efficiency of sensing elements and conduction values. The flexibility offered by thick film and thin film processes either in the preparation of materials or in the choice of shape and size of the sensor structure provides advantages over other technologies. These ceramic sensors show faster response than other types.

  11. Effect of varying relative humidity on the rancidity of cashew ...

    African Journals Online (AJOL)

    Post harvest deterioration by microbes due to improper storage condition is considered to be the major cause of spoilage and rancidity of most oil-bearing seeds like cashew nuts through lipolytic action of lipase enzyme. Roasted cashew nuts were subjected to four different storage conditions with different relative humidity ...

  12. Semmes-Weinstein Monofilaments: Influence of Temperature, Humidity, and Age

    NARCIS (Netherlands)

    Haloua, Max H.; Sierevelt, Inger; Theuvenet, Willem J.

    2011-01-01

    Purpose: To determine whether the buckling force of Semmes-Weinstein monofilaments is influenced by changes in temperature, humidity, and aging. Methods: We tested 16 Semmes-Weinstein monofflaments from North Coast Medical, varying in age from new to 12 years old. From each kit, we used the

  13. Design of a Humidity Sensor Tag for Passive Wireless Applications.

    Science.gov (United States)

    Wu, Xiang; Deng, Fangming; Hao, Yong; Fu, Zhihui; Zhang, Lihua

    2015-10-07

    This paper presents a wireless humidity sensor tag for low-cost and low-power applications. The proposed humidity sensor tag, based on radio frequency identification (RFID) technology, was fabricated in a standard 0.18 μm complementary metal oxide semiconductor (CMOS) process. The top metal layer was deposited to form the interdigitated electrodes, which were then filled with polyimide as the humidity sensing layer. A two-stage rectifier adopts a dynamic bias-voltage generator to boost the effective gate-source voltage of the switches in differential-drive architecture, resulting in a flat power conversion efficiency curve. The capacitive sensor interface, based on phase-locked loop (PLL) theory, employs a simple architecture and can work with 0.5 V supply voltage. The measurement results show that humidity sensor tag achieves excellent linearity, hysteresis and stability performance. The total power-dissipation of the sensor tag is 2.5 μW, resulting in a maximum operating distance of 23 m under 4 W of radiation power of the RFID reader.

  14. Whey protein concentrate storage at elevated temperature and humidity

    Science.gov (United States)

    Dairy processors are finding new export markets for whey protein concentrate (WPC), a byproduct of cheesemaking, but they need to know if full-sized bags of this powder will withstand high temperature and relative humidity (RH) levels during unrefrigerated storage under tropical conditions. To answ...

  15. Humidity sensing behaviour of polyaniline/magnesium chromate

    Indian Academy of Sciences (India)

    The decrease in electrical resistance was observed when the polymer composites were exposed to the broad range of relative humidity (ranging between 20 and 95% RH). This decrease is due to increase in surface electrical conductivity resulting from moisture absorption and due to capillary condensation of water causing ...

  16. Adsorption of moisture on molecular sieve adsorbents at low humidity

    International Nuclear Information System (INIS)

    Singh, V.P.; Ruthven, D.M.

    1984-07-01

    This report summarizes the results and conclusions of a contractor's study on the performance of 4A molecular sieve under very low humidity conditions, e.g., as expected in fusion reactor plants. The results suggest that: (a) very efficient regeneration of the sieve to low residual moisture contents ( 2 O/4A sieve system

  17. Urban-Rural Humidity Contrasts in Mexico City

    Science.gov (United States)

    Jáuregui, E.; Tejeda, A.

    1997-02-01

    Data from one pair of urban-suburban (Tacubaya and Airport) andone pair of urban-rural (School of Mines and Plan Texcoco) temperature and humidity measuring stations were used to illustrate specific humidity(q) contrasts in Mexico City. Results show a marked seasonal variation of q from around 7.9 g kg-1 during the dry months to 10 g kg-1 in the wet season (May-October) on both urban and suburban sites. The mean monthly contrasts for this pair of stations, albeit small, show that the city air is somewhat drier during the first half of the year. Comparison of urban and rural q on an hourly basis shows that although urban air is more humid at night the reverse is true during the afternoon. Areal distribution of q shows two centres of maximum humidity over the city at night and a corresponding minimum during the afternoon. On average the urban-rural contrasts in q were found to be somewhat smaller than the estimated uncertainty. The above results are in agreement with mid-latitude experience.

  18. Polymer-embedded stannic oxide nanoparticles as humidity sensors

    International Nuclear Information System (INIS)

    Hatamie, Shadie; Dhas, Vivek; Kale, B.B.; Mulla, I.S.; Kale, S.N.

    2009-01-01

    Stannic oxide (SnO 2 ) nanoparticles have been suspended in polyvinyl alcohol (PVA) matrix in different PVA:SnO 2 molar ratios ranging from 1:1 to 1:5 using simple chemical route. This suspension was deposited on ceramic substrate and upon drying was carefully detached from the substrate. SnO 2 -embedded self-standing, transparent and flexible thin films were hence synthesized. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques show the rutile tetragonal structure of SnO 2 with particle size ∼ 5 nm. UV-Visible spectroscopy demonstrates the band gap of 3.9 eV, which does not alter when embedded in polymer. Fourier transform infrared spectroscopy (FTIR) reveals that the properties of SnO 2 do not modify due to incorporation in the PVA matrix. The structures work as excellent humidity sensors at room temperature. For a critical PVA:SnO 2 molar ratio of 1:3, the resistance changes to five times of magnitude in 92% humidity within fraction of second when compared with resistance at 11% humidity. The sample regains its original resistance almost instantaneously after being removed from humid chamber. Nanodimensions of SnO 2 particles and percolation mechanism related to transport through polymer matrix and water molecule as a carrier has been used to understand the mechanism.

  19. Humidity distribution affected by freely exposed water surfaces

    DEFF Research Database (Denmark)

    Hygum, Morten Arnfeldt; Popok, Vladimir

    2014-01-01

    evolution of relative humidity based on statistical rate theory and computational fluid dynamics is developed. In our approach we use short-term steady-state steps to simulate the slowly evolving evaporation in the system. Experiments demonstrate considerably good agreement with the computer modeling...

  20. Stable and Selective Humidity Sensing Using Stacked Black Phosphorus Flakes.

    Science.gov (United States)

    Yasaei, Poya; Behranginia, Amirhossein; Foroozan, Tara; Asadi, Mohammad; Kim, Kibum; Khalili-Araghi, Fatemeh; Salehi-Khojin, Amin

    2015-10-27

    Black phosphorus (BP) atomic layers are known to undergo chemical degradation in humid air. Yet in more robust configurations such as films, composites, and embedded structures, BP can potentially be utilized in a large number of practical applications. In this study, we explored the sensing characteristics of BP films and observed an ultrasensitive and selective response toward humid air with a trace-level detection capability and a very minor drift over time. Our experiments show that the drain current of the BP sensor increases by ∼4 orders of magnitude as the relative humidity (RH) varies from 10% to 85%, which ranks it among the highest ever reported values for humidity detection. The mechanistic studies indicate that the operation principle of the BP film sensors is based on the modulation in the leakage ionic current caused by autoionization of water molecules and ionic solvation of the phosphorus oxoacids produced on moist BP surfaces. Our stability tests reveal that the response of the BP film sensors remains nearly unchanged after prolonged exposures (up to 3 months) to ambient conditions. This study opens up the route for utilizing BP stacked films in many potential applications such as energy generation/storage systems, electrocatalysis, and chemical/biosensing.