Trata-se de um trabalho que resultou da compilação de informação com o objectivo de fornecer informação de base aos modelos computacionais que temos em uso para diversas finalidades (docência, investigação e desenvolvimento).

Land subsidence is common in some regions of China. Various eco-environmental problems have arisen due to changes in water–rock interactions in these subsided areas, for which a comprehensive understanding of the hydrogeological setting is needed. This paper presents the general status of land subsidence in three typical subsided areas of China through the compilation of relevant data, and reviews some typical changes in the water–rock interactions in subsided areas along with related eco-environmental issues. It is found that the subsidence development and distribution are controlled by the groundwater-withdrawal intensity externally, and by the thickness and compressibility of unconsolidated sediments internally. The physical changes and related effects of water–rock interactions in subsided areas include: (1) the decreased ground elevation that caused floods, waterlogged farmland, etc.; (2) the differential subsidence that caused ground fissures; and (3) the change of seepage field that caused substantial reduction of the water resource. Chemically, the changes and related effects of water–rock interactions include: (1) the change to the chemical environment or processes due to the hydrogeologic structure alteration, which caused groundwater pollution; and (2) hydrologic mixing (seawater intrusion, artificial recharge; exchange with adjacent aquifers or aquitards), which degraded the groundwater quality. Further research on the subsided areas in China is suggested to reveal the mechanisms regarding biological and gaseous (meteorological) changes from the perspective of interacting systems among water, rocks, biological agents and gases.

The rapid population growth determines the appearance of vital needs such as mobilization of people to their places of study, work, entertainment and other activities such mobilization is performed in vehicles whose operation is slowly causing damage to the nature, on this aspect is developed in this research to be analyzed and then pose as a proposal to improve the octane of gasoline by adding hydrogen and oxygen by electrolysis of water, for reducing greenhouse gases and increasing combustion in an internal combustion engine of the vehicle fleet in the canton Latacunga, the work is divided in three sections; the first chapter is determined by the problematization and general concepts fundamental to the development of this research, in the second chapter contains methodological applications made for this job and the third chapter deals with the findings, conclusions and recommendations made to achieve the success of the investigation. | El vertiginoso crecimiento de la población determina el aparecimiento de necesidades vitales como la movilización de las personas a sus centros de estudio, trabajo, entretenimiento, y demás actividades; dicha movilización se la realiza en automotores cuyo funcionamiento, poco a poco está causando deterioro a la naturaleza, sobre este aspecto se desarrolla la presente investigación en la que se pretende analizar y posteriormente plantear como propuesta el mejoramiento del octanaje de la gasolina por la adición de hidrogeno y oxigeno mediante electrolisis del agua, para la disminución de los gases de efecto invernadero y el incremento de la combustión en un motor de combustión interna del parque automotor del cantón Latacunga, el trabajo se desarrolla en tres secciones, en el primer Capítulo está determinado por la problematización y conceptos generales, fundamentales para el desenvolvimiento de esta investigación, en el segundo Capítulo consta las aplicaciones metodológicas realizadas para este trabajo y en el Tercer Capítulo trata de los resultados, conclusiones y recomendaciones efectuadas para la consecución del éxito de la investigación

The Eocene deposits of Kazan Basin in Turkey contain a rare trona mineral which is planned to be extracted by solution mining. The complex flow dynamics and mixing mechanisms as noted from previous hydraulic and hydrochemical data need to be augmented with environmental tracer and noble gas data to develop a conceptual model of the system for the assessment of the impacts of the mining and to develop sustainable groundwater management policies throughout the area. The tracers used include the stable isotopes of water (δ²H, δ¹⁸O), δ¹³C and¹⁴C of dissolved inorganic carbon (DIC), tritium (³H), the chlorofluorocarbons CFC-11 and CFC-12, and the noble gases He and Ne. The system studied consists of three aquifers: shallow, middle, and deep. CFC data indicate modern recharge in the shallow system. The estimates of ages through¹⁴C dating for the deeper aquifer system are up to 34,000 years. Helium concentrations cover a wide range of values from 5 × 10⁻⁸to 1.5 × 10⁻⁵ cm³STP/g.³He/⁴He ratios vary from 0.09RAto 1.29RA(where RAis the atmospheric³He/⁴He ratio of 1.384 × 10⁻⁶), the highest found in water from the shallow aquifer. Mantle-derived³He is present in some of the samples indicating upward groundwater movement, possibly along a NE–SW-striking fault-like feature in the basin.

Environmental tracers (noble gases, tritium, industrial gases, stable isotopes, and radio-carbon) and hydrogeology were interpreted to determine groundwater transit-time distribution and calculate mean transit time (MTT) with lumped parameter modeling at 19 large springs distributed throughout the Upper Colorado River Basin (UCRB), USA. The predictive value of the MTT to evaluate the pattern and timing of groundwater response to hydraulic stress (i.e., vulnerability) is examined by a statistical analysis of MTT, historical spring discharge records, and the Palmer Hydrological Drought Index. MTTs of the springs range from 10 to 15,000 years and 90 % of the cumulative discharge-weighted travel-time distribution falls within the range of 2−10,000 years. Historical variability in discharge was assessed as the ratio of 10–90 % flow-exceedance (R ₁₀/₉₀%) and ranged from 2.8 to 1.1 for select springs with available discharge data. The lag-time (i.e., delay in discharge response to drought conditions) was determined by cross-correlation analysis and ranged from 0.5 to 6 years for the same select springs. Springs with shorter MTTs (<80 years) statistically correlate with larger discharge variations and faster responses to drought, indicating MTT can be used for estimating the relative magnitude and timing of groundwater response. Results indicate that groundwater discharge to streams in the UCRB will likely respond on the order of years to climate variation and increasing groundwater withdrawals.