scholarly journals A generalized Damköhler number for classifying material processing in hydrological systems

2013 ◽  
Vol 17 (3) ◽  
pp. 1133-1148 ◽  
Author(s):  
C. E. Oldham ◽  
D. E. Farrow ◽  
S. Peiffer
Keyword(s):  
Water Management ◽  
Material Processing ◽  
Land Use ◽  
Hydrological Cycle ◽  
Spatial Scales ◽  
Dynamic Balance ◽  
Biogeochemical Processes ◽  
The Past ◽  
Effective Transfer ◽  
Insight Into

Abstract. Assessing the potential for transfer of pollutants and nutrients across catchments is of primary importance under changing land use and climate. Over the past decade the connectivity/disconnectivity dynamic of a catchment has been related to its potential to export material; however, we continue to use multiple definitions of connectivity, and most have focused strongly on physical (hydrological or hydraulic) connectivity. In contrast, this paper constantly focuses on the dynamic balance between transport and material transformation, and defines material connectivity as the effective transfer of material between elements of the hydrological cycle. The concept of exposure timescales is developed and used to define three distinct regimes: (i) which is hydrologically connected and transport is dominated by advection; (ii) which is hydrologically connected and transport is dominated by diffusion; and (iii) which is materially isolated. The ratio of exposure timescales to material processing timescales is presented as the non-dimensional number, NE, where NE is reaction-specific and allows estimation of relevant spatial scales over which the reactions of interest take place. Case studies within each regime provide examples of how NE can be used to characterise systems according to their sensitivity to shifts in hydrology and gain insight into the biogeochemical processes that are signficant under the specified conditions. Finally, we explore the implications of the NE framework for improved water management, and for our understanding of biodiversity, resilience and chemical competitiveness under specified conditions.

scholarly journals The potential for material processing in hydrological systems – a novel classification approach

2012 ◽  
Vol 9 (9) ◽  
pp. 10487-10524
Author(s):  
C. E. Oldham ◽  
D. E. Farrow ◽  
S. Peiffer
Keyword(s):  
Spatial Scales ◽  
Dynamic Balance ◽  
Hydrological Regime ◽  
Climatic Conditions ◽  
Hydrologic Cycle ◽  
Biogeochemical Processes ◽  
Classification Approach ◽  
The Past ◽  
And Diffusion ◽  
Insight Into

Abstract. Assessing the potential for transfer or export of biogeochemicals or pollutants from catchments is of primary importance under changing land use and climatic conditions. Over the past decade the connectivity/disconnectivity dynamic of a catchment has been related to its potential to export material, however we continue to use multiple definitions of connectivity, and most have focused strongly on physical (hydrologicaly or hydraulic) connectivity. In this paper we use a dual-lens approach, where the dynamic balance between transport and reaction is constantly in focus, and define ecohydrological connectivity as the ability of matter and organisms to transfer within and between elements of the hydrologic cycle while undergoing biogeochemical transformation. The connectivity/disconnectivity dynamic must take into account the opportunity for a given reaction to occur during transport and/or isolation. Using this definition, we define three distinct regimes: (1) one which is ecohydrologically connected and diffusion dominated; (2) one which is ecohydrologically connected and advection dominated and (3) one which is both hydrologically and ecohydrologically disconnected. Within each regime we use a new non-dimensional number, NE, to compare exposure timescales with reactions timescales. NE is reaction-specific and allows the estimation of relevant spatial scales over which the reactions of interest are taking place. Case studies provide examples of how NE can be used to classify systems according to their sensitivity to shifts in hydrological regime, and gain insight into the biogeochemical processes that are signficant under the specified conditions. Finally, we explore the implications of this dual-lens framework for improved water management, for our understanding of biodiversity, resilience and biogeochemical competitiveness under specified conditions

scholarly journals Land Use Projections Under Alternative Policies: A Transition Matrix Approach

1979 ◽  
Vol 8 (2) ◽  
pp. 87-99 ◽  
Author(s):  
Bruce E. Lindsay ◽  
Daniel L. Dunn
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Land Use Planning ◽  
Current Trend ◽  
Land Use Policy ◽  
Decision Makers ◽  
Policy Makers ◽  
The Past ◽  
Accelerated Growth ◽  
Insight Into

As a result of accelerated growth during the past decade, land use change over time and its accompanying problems represents a policy area germane to New Hampshire. Accurate projections of the future pattern of land use would be helpful to decision makers responsible for land use policy. Such projections could assist policy makers either directly in formulating land use plans or indirectly in justifying the need (or lack of need) for overt land use planning. Future projections, based upon various alternative land use policy scenarios, will increase the quantitative supply of information to decision makers in a two-fold manner. First, such estimates provide an insight into the current trend in land use mix and, secondly, give an overview of what impacts various policies directly have upon land use change.

scholarly journals Homokhátság - a special rural area affected by aridification in the Carpathian basin, Hungary

2017 ◽  
Vol 9 (1) ◽  
pp. 29-50 ◽  
Author(s):  
András Donát Kovács ◽  
Edit Hoyk ◽  
Jenő Zsolt Farkas
Keyword(s):  
Land Use ◽  
Local Economy ◽  
Rural Environment ◽  
Sustainable Rural Development ◽  
The Past ◽  
Starting Point ◽  
Emerging Issues ◽  
Specific Factors ◽  
Characteristic Features ◽  
Insight Into

Abstract In Hungary, the aridification primarily affects the Great Hungarian Plain, most specifically the “Homokhátság” area which is part of the Danube-Tisza Interfluve. On the basis of our experience gained in the past 15 years, we would like to give an insight into the complex problems of this rural region. Our starting point is the aridification process and water scarcity which are characteristic features of this area for the last century. We investigate the related problems in land use management such as unfavourable land use and vegetation changes and the challenges in the local economy and social sustainability. In this respect we introduce the emerging issues in agriculture, forestry and nature conservation which may be relevant in European context too. We have discovered specific factors related to the devaluation of the rural environment and found that significant part of the unfavourable phenomena can be explained by the combined effect of climatic changes, improper land use and inappropriate environmental management. Based on our findings we outline a possible regional pathway for a sustainable rural development.

scholarly journals Linking carbon and water cycles using stable isotopes across scales: progress and challenges

2011 ◽  
Vol 8 (2) ◽  
pp. 2659-2719 ◽  
Author(s):  
C. Werner ◽  
F. Badeck ◽  
E. Brugnoli ◽  
B. Cohn ◽  
M. Cuntz ◽  
...  
Keyword(s):  
Spatial Scales ◽  
Isotope Analysis ◽  
Biogeochemical Processes ◽  
Powerful Approach ◽  
Oxygen And Hydrogen Isotopes ◽  
Technological Developments ◽  
Temporal And Spatial ◽  
Insight Into ◽  
Simultaneous Assessment ◽  
Water Cycles

Abstract. Stable isotope analysis is a powerful tool for tracing biogeochemical processes in the carbon and water cycles. One particularly powerful approach is to employ multiple isotopes where the simultaneous assessment of the D/H,18O/16O and/or 13C/12C in different compounds provide a unique means to investigate the coupling of water and carbon fluxes at various temporal and spatial scales. Here, we present a research update on recent advances in our process-based understanding of the utilization of carbon, oxygen and hydrogen isotopes to lend insight into carbon and water cycling. We highlight recent technological developments and approaches, their strengths and methodological precautions with examples covering scales from minutes to centuries and from the leaf to the globe.

scholarly journals Recasting catchment water balance for water allocation between human and environmental purposes

2015 ◽  
Vol 12 (1) ◽  
pp. 911-938
Author(s):  
S. Zhou ◽  
Y. Huang ◽  
Y. Wei ◽  
G. Wang
Keyword(s):  
Water Management ◽  
Land Use ◽  
Water Balance ◽  
Water Allocation ◽  
Dynamic Balance ◽  
Ecological Systems ◽  
Water Diversion ◽  
Global Challenge ◽  
Period 2 ◽  
Murray Darling Basin

Abstract. Rebalancing water allocation between human consumptive uses and the environment in water catchments is a global challenge. The conventional water balance approach which partitions precipitation into evapotranspiration (ET) and surface runoff supports the optimization of water allocations among different human water use sectors under the cap of water supply. However, this approach is unable to support the emerging water management priority issue of allocating water between societal and ecological systems. This paper recast the catchment water balance by partitioning catchment total ET into ET for the society and ET for the natural ecological systems, and estimated the impacts of water allocation on the two systems in terms of gross primary productivity (GPP), in the Murray–Darling Basin (MDB) of Australia over the period 1900–2010. With the recast water balance, the more than 100 year water management in the MDB was divided into four periods corresponding to major changes in basin management: period 1 (1900–1956) expansion of water and land use by the societal system, period 2 (1956–1985) maximization of water and land use by the societal system, period 3 (1985–2002) maximization of water diversion for the societal system, and period 4 (2002–present) rebalancing of water and land use between the societal and ecological systems. The recast water balance provided new understandings of the water and land dynamics between societal and ecological systems in the MDB, and it highlighted the experiences and lessons of catchment water management in the MDB over the last more than 100 years. The recast water balance could serve as the theoretical foundation for water allocation to keep a dynamic balance between the societal and ecological systems within a basin for sustainable catchment development. It provides a new approach to advance the discipline of socio-hydrology.

In situ UV-Vis sensors record spatially and temporally different diurnal patterns in solute concentrations in tropical montane headwater streams: reality or artefact?

2020 ◽  
Author(s):  
Suzanne Jacobs ◽  
Björn Weeser ◽  
Mariana Rufino ◽  
Lutz Breuer
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Spatial Scales ◽  
Diurnal Changes ◽  
Biogeochemical Processes ◽  
Mobile Sensor ◽  
Position Change ◽  
Diurnal Patterns

<p>There is a need to better understand the driving factors of and interactions between hydro-biogeochemical processes at different temporal and spatial scales to inform water management. Especially for tropical montane ecosystems, which are recognized as important freshwater sources, the required data and knowledge are missing. To address this knowledge gap, a long-term hydrological monitoring network was set up in the Mau Forest Complex, Kenya. The network covers three sub-catchments (27–36 km²) dominated by either tropical montane forest, smallholder agriculture or commercial tea plantations, within a 1021 km² mixed land use catchment. A 5-year dataset of nitrate and dissolved organic carbon concentrations measured at 10-minute interval with <em>in situ</em> UV-Vis sensors was analysed for short-term changes in solute concentrations. The analysis revealed small diurnal patterns (amplitude <0.25 mg N or C L<sup>−1</sup>, decreasing with increasing discharge) in solute concentrations in all streams. In addition, the timing of the minima and maxima differed between catchments and seasons, suggesting and influence of land use and seasonality on the occurrence of in-stream biogeochemical processes. However, unusual and abrupt changes in the diurnal patterns were observed after a change in sensor position or exchange of sensors. We therefore developed an experiment to test the validity of the observed diurnal patterns. A second, mobile sensor was installed at each site for a period of more than three weeks. After measuring in parallel position to the fixed sensor for two weeks, the position (orientation, depth) was changed or the measurement gap was shaded. In parallel position, the patterns in solute concentrations recorded by the mobile sensor agreed better with those measured by the fixed sensor for dissolved organic carbon (<em>r</em>>0.98) than for nitrate (<em>r</em>=0.43–0.81). However, shading the sensor or a position change resulted in inconsistent changes in the recorded patterns. Larger changes in solute concentrations, e.g. as a result of rainfall events, were reproduced well by the mobile sensor. The results of our study suggest that diurnal changes in solute concentrations with an amplitude close sensor accuracy measured with <em>in situ</em> UV-Vis sensors should be interpreted with caution. The experiment was not conclusive as to what caused the differences in observed patterns. Further experimental work is required to understand the causes and to develop recommendations for the use of UV-Vis sensors in hydro-biogeochemical research.</p>

Recovery boiler sootblowers: History and technological advances

TAPPI Journal ◽  
2015 ◽  
Vol 14 (1) ◽  
pp. 51-60
Author(s):  
HONGHI TRAN ◽  
DANNY TANDRA
Keyword(s):  
Cfd Modeling ◽  
Computing Systems ◽  
The Past ◽  
Technological Advances ◽  
Recovery Boilers ◽  
Computational Fluid Dynamics Cfd ◽  
Recovery Boiler ◽  
Steam Parameters ◽  
Insight Into ◽  
Deposit Removal

Sootblowing technology used in recovery boilers originated from that used in coal-fired boilers. It started with manual cleaning with hand lancing and hand blowing, and evolved slowly into online sootblowing using retractable sootblowers. Since 1991, intensive research and development has focused on sootblowing jet fundamentals and deposit removal in recovery boilers. The results have provided much insight into sootblower jet hydrodynamics, how a sootblower jet interacts with tubes and deposits, and factors influencing its deposit removal efficiency, and have led to two important innovations: fully-expanded sootblower nozzles that are used in virtually all recovery boilers today, and the low pressure sootblowing technology that has been implemented in several new recovery boilers. The availability of powerful computing systems, superfast microprocessors and data acquisition systems, and versatile computational fluid dynamics (CFD) modeling capability in the past two decades has also contributed greatly to the advancement of sootblowing technology. High quality infrared inspection cameras have enabled mills to inspect the deposit buildup conditions in the boiler during operation, and helped identify problems with sootblower lance swinging and superheater platens and boiler bank tube vibrations. As the recovery boiler firing capacity and steam parameters have increased markedly in recent years, sootblowers have become larger and longer, and this can present a challenge in terms of both sootblower design and operation.

Upcoming Drifts In Bio-Similars

2020 ◽  
Vol 15 ◽  
Author(s):  
Geeta Aggarwal ◽  
Manju Nagpal ◽  
Ameya Sharma ◽  
Vivek Puri ◽  
Gitika Arora Dhingra
Keyword(s):  
Metabolic Diseases ◽  
Market Competition ◽  
Current Status ◽  
Medicinal Products ◽  
The Past ◽  
Biologic Activity ◽  
Emerging Trends ◽  
Regulatory Guidelines ◽  
Food Drug Administration ◽  
Insight Into

Background: Biopharmaceuticals such as Biologic medicinal products have been in clinical use over the past three decades and have benefited towards the therapy of degenerative and critical metabolic diseases. It is forecasted that market of biologics will be going to increase at a rate of 20% per year, and by 2025, more than ˃ 50% of new drug approvals may be biological products. The increasing utilization of the biologics necessitates for cost control, especially for innovators products that have enjoyed a lengthy period of exclusive use. As the first wave of biopharmaceuticals is expired or set to expire, it has led to various opportunities for the expansion of bio-similars i.e. copied versions of original biologics with same biologic activity. Development of biosimilars is expected to promote market competition, meet worldwide demand, sustain the healthcare systems and maintain the incentives for innovation. Methods: Appraisal of published articles from peer reviewed journals, PubMed literature, latest news and guidelines from European Medicine Agency, US Food Drug Administration (FDA) and India are used to identify data for review. Results: Main insight into the quality requirements concerning biologics, current status of regulation of biosimilars and upcoming challenges lying ahead for the upgrading of marketing authorization of bio-similars has been incorporated. Compiled literature on therapeutic status, regulatory guidelines and the emerging trends and opportunities of biosimilars has been thoroughly stated. Conclusion: Updates on biosimilars will support to investigate the possible impact of bio-similars on healthcare market.

Sign in / Sign up

Export Citation Format

Share Document