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Decomposition approach of the nitrogen generation process : Empirical study on the Shimabara Peninsula in Japan

Groundwater nitrate pollution is one of the most prevalent water-related environmental problems worldwide. The objective of this study is to identify the determinants of nitrogen pollutant changes with a focus on the nitrogen generation process. The novelty of our research framework is to cost-effectively identify the factors involved in nitrogen pollutant generation using public data. This study

Influence of oxygen flow rate and compost addition on reduction of organic matter in aerated waste layer containing mainly incineration residue

Landfilling municipal solid waste incineration (MSWI) residue alkalizes the waste layer, causing a subsequent decrease in microbial activity and a delay in the decomposition of organic matter. In this study, efficiencies of neutralization of the leachate and organic matter decomposition in the waste layer in a column filled with MSWI residue using aeration and compost addition were evaluated. Tota

Quantitative evaluation of macroscopic longitudinal dispersivity for one-dimensional flow

Macroscopic dispersivity is the most important factor for analysing the convection-dispersion equation (CDE) at the field scale, and it is well known that macroscopic dispersivities vary with the scale of observation. In this study, artificial heterogeneous hydraulic conductivity fields were generated with the stochastic fractal model (fς model). Macroscopic dispersivities were evaluated for two-d

Effects of Recharge Wells and Flow Barriers on Seawater Intrusion

The installation of recharge wells and subsurface flow barriers are among several strategies proposed to control seawater intrusion on coastal groundwater systems. In this study, we performed laboratory-scale experiments and numerical simulations to determine the effects of the location and application of recharge wells, and of the location and penetration depth of flow barriers, on controlling se

Reactive transport column experiment in volcanic ash soil and numerical modelling with anion and cation exchange reactions

Groundwater contamination by nitrate from agricultural fields is a problem shared by many parts of the world. Kagoshima prefecture, Japan, is an important agricultural district experiencing this problem. In this study, laboratory column experiments were performed and a numerical model was developed to improve understanding of nitrate transport process through volcanic ash soils overlying the aquif

Laboratory-scale saltwater behavior due to subsurface cutoff wall

Artificial subsurface barriers are among several countermeasures proposed to control seawater intrusion into coastal aquifers. We performed experimental and numerical studies to investigate the dynamics of residual saltwater trapped in the storage area upon installation of cutoff walls. Experimental results showed that after wall installation, the residual saltwater wedge initially flattened causi

Modeling the water budget in a deep caldera lake and its hydrologic assessment : Lake Ikeda, Japan

The hydrologic assessment of a lake water budget can be helpful in achieving proper water management and sustainable water use. A model to analyze a lake water budget was developed and verified for Lake Ikeda, Japan. Lake evaporation was estimated by numerical analyses of lake water temperature and the lake energy budget. Inflow from the lake catchment area and leakage from the lake bottom were es

Saltwater dynamics due to cut-off wall installation in coastal unconfined aquifers : Experimental and numerical studies

In the construction of subsurface dams in coastal aquifers, investigations of the movement and removal of residual saltwater in the storage area are not usually carried out because of difficulties in monitoring. Experimental and numerical studies were thus performed to understand the saltwater dynamics due to the installation of cut-off walls. Experimental results for cut-off walls with opening on

Experimental and numerical study on nitrate transport process through volcanic ash soil

Column experiments using two Japanese volcanic ash soils (Akahoya and Kuroboku soils) were carried out to improve understanding of solute transport characteristics through volcanic ash soil. As the contaminant source, a mixed solution of KNO3 and K2SO4 was applied from the top of the column. Temporal changes of cations and anions in the effluent were measured at prescribed time intervals. Breakthr

Impact of agricultural water management on lake water budget : A case study of Lake Ikeda, Japan

Hydrological assessment of the effect of water utilization on a lake water budget isindispensable for proper water management. A model to estimate lake water level was developed for Lake Ikeda, Japan, and was applied to investigate the lake water budget and to examine the effect of agricultural water management on the lake water level. The calculated lake water levels agreed well with the measured

Observations and modelling of seawater intrusion for a small limestone island aquifer

Seawater intrusion in coastal aquifers is a widespread and serious problem in many parts of the world. Groundwater degradation due to seawater intrusion is often accentuated in small island aquifers due to overpumping or limited replenishing amounts of precipitation. Seawater intrusion and groundwater dynamics in a small limestone aquifer on Yoron Island, Japan, were investigated. Observations in

Application of global optimization methods to evaluation of chemical reaction terms in reactive solute transport analysis

Two global optimization methods based on Genetic Algorithms (GA) and Shuffled Complex Evolution (SCE-UA) method were examined to evaluate reaction terms in a reactive solute transport model involving cation exchange reactions. Although the both algorithms can minimize the objective function after succession of generations, SCE-UA method appears superior to GA in that its performance depends less o

Numerical study on saltwater intrusion in a heterogeneous stratified aquifer

In a costal aquifer, saltwater intrusion is frequently observed due to an excess exploitation. There are many researches focused on the saltwater intrusion. However, there are few researches, which take into consideration the mixing processes in a stratified heterogeneous aquifer. In the present study, a laboratory experiment and numerical simulation are made in order to understand the phenomena i

Evaluation of the transition characteristics of macroscopic dispersion and estimation of the non-uniform hydrogeological structure

In general, a natural aquifer has a hydrogeologically non-uniform structure. The movement of pollutants in groundwater is affected by such structural properties during transport by local advection and microscopic dispersion. The macroscopic dispersion coefficient increases linearly with travel distance or travel time at the initial stage after the pollutant is released, and then converges asymptot

Numerical study of non-reactive tracer transport in a heterogeneous field, with random microscopic dispersivity

One of the most important processes for the groundwater environment is macroscopic dispersion in geological media. In this study, laboratory experiments and numerical simulations are carried out in order to understand the transport of a non-reactive tracer in a heterogeneous porous medium. The method of characteristics and the implicit finite difference method are employed for numerical solutions

Domkyrkoentreprenaden : förspel, genomförande och avslutning

En berättelse om entreprenaden bakom byggandet av Lunds domkyrka. Den lokala aristokratins erfarenhet av entreprenader, anskaffandet av arbetskraft och Harald Blåtands första etablering i Lund inleder redogörelsen. Den första byggnaden på kyrkoplatsen, troligen ett kloster, får byggnadsmaterialet fråm Helsingborg- och Ystadstrakten. Den stående domkyrkans sten kommer från Hallaröd/Munkarp. En fyll

Lilla Harrie och stora Örtofta : Dynamik och divergens. Två byar i Harjager

De två byarna har samma geologiska och näringstekniska förutsättningar. Lilla Harrie var en "normal" by med ett bofast frälse och ett antal gårdar fram till 1300-talet medan Örtofta uppstod på direktiv av kyrka/kung omkring 1100 då en kyrklig aristokrati etableras, sannolikt som vägförvaltare för den väg och bro där stenen till Lunds domkyrka transporteras. Det kyrkliga frälset övergår i ett värld

Frosta : Mittens härad och Saxes röjning

Under 1100-talet började allmänningsskogarna i skåne att koloniseras. Östra Sallerup- Saxildrup Ruma- är en kolonisationstrakt. Någon av Hvide familjen vid namn Saxo eller liknande fick domänen och engagerade nio stormän som medkolonisatörer. En kyrka byggdes då kolonisterna var många nog. I kyrkan gjordes bland annat en kalkmålning vars enda kända samtida motsvarighet finns som en mosaik i klostr

Follow-up on: optimizing lesion detection in small bowel capsule endoscopy and beyond: from present problems to future solutions

Introduction: This review presents noteworthy advances in clinical and experimental Capsule Endoscopy (CE), focusing on the progress that has been reported over the last 5 years since our previous review on the subject. Areas covered: This study presents the commercially available CE platforms, as well as the advances made in optimizing the diagnostic capabilities of CE. The latter includes recent

Overcoming the fear of making a crappy sketch

This paper discusses which freehand drawing skills a designer needs in the 21st century and why not more people are using sketching as a creative tool. Are design schools teaching the adequate skills needed today? In the past 5-10 years focus has shifted from product design to experience design and the skills needed to make high end drawings might not be needed to the same extent. 3D computational