2,630 research outputs found
Natural and Technological Hazards in Urban Areas
Natural hazard events and technological accidents are separate causes of environmental impacts. Natural hazards are physical phenomena active in geological times, whereas technological hazards result from actions or facilities created by humans. In our time, combined natural and man-made hazards have been induced. Overpopulation and urban development in areas prone to natural hazards increase the impact of natural disasters worldwide. Additionally, urban areas are frequently characterized by intense industrial activity and rapid, poorly planned growth that threatens the environment and degrades the quality of life. Therefore, proper urban planning is crucial to minimize fatalities and reduce the environmental and economic impacts that accompany both natural and technological hazardous events
SCENARIO DEVELOPMENT FOR URBAN WATER MANAGEMENT PLANNING FOR UNCERTAINTY
The urban water sector is confronted with a multitude of challenges. Rapid population growth, changing political landscapes, aging water infrastructures, and the worsening climate crisis are creating a range of uncertainties in the sector around managing water. Scenarios have been used extensively in the environmental domain to plan for and capture uncertainties to develop plausible futures, including the field of urban water management. Scenarios are key in enabling plans and creating roadmaps to attain desired futures. Despite the advantages and opportunities that scenarios offer for planning, they also have limitations; generally, and within the urban water space. Firstly, the growing uncertainty surrounding urban water management systems necessitates a focused review specifically aimed at the use of scenarios in urban water management. This thesis presents a systematic review to empirically investigate the crucial dimensions of urban water scenarios. Through this review, key knowledge gaps are highlighted, and recommendations are proposed to address these gaps. Secondly, scenarios often depict distressing, almost dystopian futures. Though negative future visions help understand the consequences of present trends and aid in anticipating imminent threats, the limited exploration of positive future visions can make it challenging to find the direction to transform. Optimistic scenarios delve into what people want for the future and capture how their aspirations shape them. Imagining positive visions encourage innovative thinking, creates agency, and creates pathways to desired futures. There is therefore a recognition to move towards more positive, desirable futures. This thesis uses a narrative, participatory scenario process, the SEEDS method, to develop positive visions of urban water futures. The Greater Sydney region in New South Wales, Australia is used as a case study to evaluate the applicability of this approach for urban water management. The urban water sector in the Greater Sydney region faces a multitude of challenges including impacts from climate change, managing diverse water supply sources, and meeting future water demand. These challenges create an increasingly uncertain future for the water sector, where the scale and nature of water services needed in the Greater Sydney region can be unclear. Hence, the Greater Sydney region is selected as the case study region to apply the SEEDS method and develop scenarios for urban water management to plan for future uncertainties. Thirdly, only a few scenario studies include surprises, the unexpected events, which make scenarios useful for planning. Challenges around capturing surprises in scenarios include a lack of structured approaches as well as a lack of evaluation of those methods that have been developed. This thesis discusses the effectiveness and suitability of various surprise methods for scenario development. These methods have been applied in the context of the SEEDS method for urban water management. Finally, there is a lack of evaluation of the tools used to cope with surprises as well as a lack of evaluation efforts of urban water management scenario studies. The assessment of the SEEDS approach for urban water management as well as the different surprise methods for scenario development requires evaluation criteria. This thesis develops and presents an evaluation criteria list based on existing literature that captures key criteria required for adequate assessment of the surprise methods and the scenario process. This thesis contributes to the fields of scenario development and urban water management, and the use of surprises within scenarios. Critical gaps in existing urban water management scenario practices are highlighted and key recommendations are proposed to fill the gaps. Through the pilot study and full-scale implementation of a positive-visioning, narrative-based scenario approach - the SEEDS method, the thesis demonstrates that the SEEDS method is applicable for urban water planning and shows potential for use at different stages of water planning. The positive visions generated through the SEEDS method highlight fundamental aspirations for the urban water sector, possible challenges, and conflicts, and discuss pathways to achieve positive future visions. By using in-situ experimentation and engaging participants with expertise in the relevant field, this thesis provides a realistic evaluation of the scenario process and surprise methods. This thesis thus fills the critical gap about the lack of evaluation in urban water management scenario processes by assessing the scenario method using selected evaluation criteria. Further, the thesis contributes towards the development of quality surprise methods through application and evaluation, thus addressing the gap about the lack of evaluation of the methods used to explore surprise events. Finally, the lack of surprises in scenarios is addressed by presenting different methods that can be used to explore surprise events. Guidance is provided to researchers working with scenario development to understand the different surprise methods available and for choosing the appropriate method(s) to plan for uncertain futures
Analysing the performance of radiological monitoring network during nuclear accidents
JRODOS was used to simulate the dispersion of airborne radioactive material from a point source over the period
2012–2015. In total, 1331 radioactive plumes were simulated with the objective to investigate the influence of
changes in meteorological conditions in the performance of the monitoring network. For this purpose, the
existing set of 84 monitoring stations included in the EUropean Radiological Data Exchange Platform (EURDEP)
system in an area of 200 km around the source point is taken as reference. A methodology is presented for
quantitative evaluation of the variability of the number of stations affected, the time of the first detection, the
maximum registered and differences between the maximum values match in the network and in the simulated
plumes. The results show seasonal differences in all of these parameters according to changes in the size and
shape of the affected area due to meteorological conditions. There are large differences in the number of
monitoring stations affected by the plumes, from 2 to 74; in the timing and location of the first alert given by the
network, from 1 to more than 5 h and faster along the west-east axis from the source; and in level of maximum
gamma dose rate detected by the monitoring stations, from 0.17 nSv/h in summer to 0.22 nSv/h in autumn.
These results show the need to consider this type of analysis over the years in the design of monitoring networks
and in the development of nuclear emergency preparedness and response (EP&R) plans
Evacuação de Edifícios – Caso de estudo de um edifício escolar
O objetivo deste trabalho é o levantamento dos aspetos que influenciam o tempo de evacuação
num edifício escolar, desde o comportamento humano às caraterísticas físicas do edifício e às
metodologias possíveis de adotar para a gestão da emergência, com vista a calcular o tempo
necessário e disponível para a evacuação do referido edifício. A evacuação de edifícios em
situação de incêndio tem como propósito a proteção da vida humana que é inseparável das
condições de emergência as quais são afetadas por fatores de difícil determinação e que
necessitam de ser definidos para estimar o tempo e as condições de evacuação.info:eu-repo/semantics/publishedVersio
Beam scanning by liquid-crystal biasing in a modified SIW structure
A fixed-frequency beam-scanning 1D antenna based on Liquid Crystals (LCs) is designed for application in 2D scanning with lateral alignment. The 2D array environment imposes full decoupling of adjacent 1D antennas, which often conflicts with the LC requirement of DC biasing: the proposed design accommodates both. The LC medium is placed inside a Substrate Integrated Waveguide (SIW) modified to work as a Groove Gap Waveguide, with radiating slots etched on the upper broad wall, that radiates as a Leaky-Wave Antenna (LWA). This allows effective application of the DC bias voltage needed for tuning the LCs. At the same time, the RF field remains laterally confined, enabling the possibility to lay several antennas in parallel and achieve 2D beam scanning. The design is validated by simulation employing the actual properties of a commercial LC medium
Characterization of harmful algal bloom frequency, severity, and spatial extent in Oklahoma reservoirs utilizing the cyanobacteria assessment network
Harmful algal blooms (HABs) pose significant threats to human health and the environment. Monitoring them in inland waterbodies is a challenging and costly task. Remote sensing technology is an increasingly useful tool in monitoring and managing HABs, providing timely information on their bloom dynamics. The Cyanobacteria Assessment Network (CyAN) was developed to provide a consistent and uniform program for HAB detection and characterization across the United States. CyAN utilizes the Ocean and Land Colour Imagers (OLCI) aboard Sentinel 3A and 3B to provide near daily imagery of the major waterbodies across the country. The objective of this study is to characterize the frequency, spatial extent, and severity of HABs in Oklahoma Reservoirs utilizing CyAN. Sixty nine waterbodies were selected for analysis. They include the largest lakes and reservoirs in Oklahoma. Frequency, spatial extent, and severity were assessed for trends over the six-year study period (2017-2022). Trend analysis was grouped into four bloom categories: high (>100,000 cells/ml), medium (20,000-100,000 cells/ml), low (<20,000 cells/ml), and total bloom. High, medium, and low-risk bloom thresholds are based off of the World Health Organizations risk of health impact thresholds. Total blooms represent any bloom level above sensor detection. The findings of this research indicate that statewide HABs are increasing in frequency over the study period for all bloom categories. The spatial extent of HABs is increasing statewide for all bloom risk categories. Bloom severity is increasing for multiple individual waterbodies. Significant differences in bloom frequency, severity, and spatial extent are observed between trophic states. The findings of this research highlight the potential of remote sensing as a valuable tool for HAB monitoring and provide insights for developing effective HAB management strategies
Natural and anthropogenic dynamics of the vegetation on the Eastern Cantabrian Coast: Late Pleistocene, Holocene and Anthropocene.
338 p.Los ecosistemas costeros se han caracterizado siempre por su dinamismo y su continua exposición a cambios de carácter natural, como las oscilaciones climáticas o la actividad geofísica de la Tierra. Sin embargo, el ser humano se ha convertido gracias a su desarrollo evolutivo y tecnológico en un agente muy agresivo de transformación y alteración de estos ecosistemas. La vegetación es uno de los elementos que mejor refleja los cambios que se han producido a lo largo de la historia de nuestro planeta. Por eso, en esta tesis doctoral se ha realizado el estudio de 5 sondeos largos y 5 sondeos cortos, 7 de ellos en estuarios, 2 de ellos marinos y 1 en un antiguo lago kárstico con el objetivo de registrar el marco cronológico más amplio posible a la vez que analizamos de manera más detallada los momentos históricos de mayor impacto humano. Estos sondeos nos han permitido retroceder en el tiempo hasta el Pleistoceno y el Holoceno llegando hasta cronologías recientes del Antropoceno. Durante el Pleistoceno, se observan dinámicas de cambio en la vegetación, con alternancia en la dominancia de la vegetación arborea y herbácea. Estas oscilaciones climáticas registradas en la vegetación se corresponderían con eventos muy fríos y secos (eventos Heinrich/H-E. La dinámica de la vegetación mostrada por los sondeos encuadrados cronológicamente en el Holoceno, muestran generalmente una recuperación de la vegetación de tipo boscoso. Esto podría deberse a la mejora climática ocurrida tras el Younger Dryas con un aumento muy rápido de las temperaturas (Optimo Climático Holoceno). En torno al ~6.000 años cal BP, la actividad humana se empieza a hacer más notable en los registros sedimentarios estuarinos. Durante el Antropoceno, la vegetación durante los últimos 200 años. El impacto humano en las zonas estuarinas desde el siglo XIX se intensificó, debido fundamentalmente a la Revolución Industrial. En el caso concreto de la Península Ibérica, es precisamente en la Cornisa Cantábrica donde el proceso industrializador tiene su mayor desarrollo
Long-Term Spatial and Temporal Assessment of Criteria Air Pollutants Concentration Trends in the Lower Rio Grande Valley Region of Texas, USA
Air pollution is a substantial environmental challenge all over the world. This study investigated the long-term air pollution levels in the Lower Rio Grande Valley region, by utilizing data collected from five continuous ambient monitoring stations in two counties over 23 years, from January 2000 to December 2022, to analyze daily, monthly, and seasonal variations of different pollutants, including ground-level ozone, particulate matter, and carbon monoxide. This study also identified distinct daily and seasonal patterns for O3, PM2.5, PM10, and CO at each monitoring site, influenced by factors such as traffic emissions, temperature, solar radiation, indoor heating, and weather conditions. Finally, this study explored the long-term patterns in annual pollutant concentrations to understand the impact of urbanization and community development on air quality. This finding is essential for policymakers to develop effective air quality management strategies to minimize pollution levels and their adverse effects on human health and the ecosystem
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