124 research outputs found

    An analytical algorithm of porosity–permeability for porous and fractured media: extension to reactive transport conditions and fitting via flow-through experiments within limestone and dolomite

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    Accurate prediction of permeability evolution is essential for forecasting the long-term performance and lifetime of hydrothermal reservoirs, an important goal in the geothermal, ore, and petroleum industries. Erol et al. (Transp Porous Media 120(2):327–358, 2017. https://doi.org/10.1007/s11242-017-0923-z) introduced a general (non-empirical) analytical Kozeny–Carman type equation for predicting matrix and fracture permeability during single-phase, non-reactive flow. Here we incorporate the equation into an algorithm for addressing the influence on porous and fractured media permeability of the transient reactive processes of mineral dissolution and precipitation. Analytical algorithm predictions are identical to permeability values measured during fluid circulation through limestone and dolomite core samples from the Campine Basin deep geothermal system in Belgium. Benchmarking used identical values for initial hydraulic aperture dimension and porosity, measured during fluid circulation based on nondestructive micro-CT imaging. Analytical algorithm predictions of reactive surface area and fracture porosity are similar to results based on the TOUGHREACT reactive transport code. TOUGHREACT implements several well- established power-law models for predicting permeability, notably Civan (AIChE J 47(2):1167–1197, 2001. https://doi.org/10.1002/aic.690470206) and Verma and Pruess (J Geophys Res Solid Earth 93:1159–1173, 1988. https://doi.org/10.1029/jb093ib02p01159). However, these models rely on specification of empirical exponents, which are not straightforward to measure. Our results suggest that a more general, computationally inexpensive analytical method can lead to accurate permeability calculation

    Policing mining: In outer-space greed and domination vs. peace and equity a governance for humanity!

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    Staking claim and ownership has remained an antagonistic issue for nations, resulting in many international conflicts. This is particularly so in disputed territories or areas which are deemed the heritage of mankind. In the next 50-years mining in space is set to become a reality and rather than being used to become an asset to man/society and create an equitable world, it is likely to be a battleground for greed and sovereign dominance – an overspill from Earth. This paper researches the conflict between greed and dominance vs. peace and equity in respect to space - mineral resources, providing historical contextualization, opinion, thoughts and interpretation. Hence, consideration is given to international approaches and who should ‘police,’ plus the governance of, space riches. The research largely considers the stance of the USA in this respect. The relevance of travel and travel modes (particularly air) and ownership of the sky is reviewed, so as to provide comparison and (historical) contextualization – identifying issues previously encountered when man looks to both travel and acquire assets by these means. The latest position of asteroid mining is also explored and ‘lessons from Earth’ are revisited as part of this research – which is largely considered and undertaken from a legal (discipline) perspective

    Development and initial testing of a computer-based patient decision aid to promote colorectal cancer screening for primary care practice

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    BACKGROUND: Although colorectal cancer screening is recommended by major policy-making organizations, rates of screening remain low. Our aim was to develop a patient-directed, computer-based decision aid about colorectal cancer screening and investigate whether it could increase patient interest in screening. METHODS: We used content from evidence-based literature reviews and our previous decision aid research to develop a prototype. We performed two rounds of usability testing with representative patients to revise the content and format. The final decision aid consisted of an introductory segment, four test-specific segments, and information to allow comparison of the tests across several key parameters. We then conducted a before-after uncontrolled trial of 80 patients 50–75 years old recruited from an academic internal medicine practice. RESULTS: Mean viewing time was 19 minutes. The decision aid improved patients' intent to ask providers for screening from a mean score of 2.8 (1 = not at all likely to ask, 4 = very likely to ask) before viewing the decision aid to 3.2 afterwards (difference, 0.4; p < 0.0001, paired t-test). Most found the aid useful and reported that it improved their knowledge about screening. Sixty percent said they were ready to be tested, 18% needed more information, and 22% were not ready to be screened. Within 6 months of viewing, 43% of patients had completed screening tests. CONCLUSION: We conclude that a computer-based decision aid can increase patient intent to be screened and increase interest in screening. Practice Implications: This decision aid can be viewed by patients prior to provider appointments to increase motivation to be screened and to help them decide about which modality to use for screening. Further work is required to integrate the decision aid with other practice change strategies to raise screening rates to target levels

    Children must be protected from the tobacco industry's marketing tactics.

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    Physiological Correlates of Volunteering

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    We review research on physiological correlates of volunteering, a neglected but promising research field. Some of these correlates seem to be causal factors influencing volunteering. Volunteers tend to have better physical health, both self-reported and expert-assessed, better mental health, and perform better on cognitive tasks. Research thus far has rarely examined neurological, neurochemical, hormonal, and genetic correlates of volunteering to any significant extent, especially controlling for other factors as potential confounds. Evolutionary theory and behavioral genetic research suggest the importance of such physiological factors in humans. Basically, many aspects of social relationships and social activities have effects on health (e.g., Newman and Roberts 2013; Uchino 2004), as the widely used biopsychosocial (BPS) model suggests (Institute of Medicine 2001). Studies of formal volunteering (FV), charitable giving, and altruistic behavior suggest that physiological characteristics are related to volunteering, including specific genes (such as oxytocin receptor [OXTR] genes, Arginine vasopressin receptor [AVPR] genes, dopamine D4 receptor [DRD4] genes, and 5-HTTLPR). We recommend that future research on physiological factors be extended to non-Western populations, focusing specifically on volunteering, and differentiating between different forms and types of volunteering and civic participation
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