Environmental Engineering

Successful mechanical cleanouts and acid chemical stimulations in production and injection wells at the Berlin, Ahuachapan, Chinameca and San Vicente geothermal field were performed over the past 10 years, giving great improvements in power generation and permeability enhancement in injection wells. The application of these techniques delivered an accumulative increment of more than 60 MWe in power production and 752 kg/s of injection capacity. Chemical stimulations using the rig to clean up to four zones, has given improvements close to 200% while acid jobs through the well head the improvement has been 40%, when cleaning only the first permeable zone. Chemical stimulation has been applied to production wells with mud and cutting damage, production wells with calcite scaling and injection wells with silica scale and mud damage.

Thirty-seven years of fisheries records covering a fishing area of 6231 ha in the lower Havel River, Germany, have been analysed to address two issues: (1) detection of the effects of habitat bottlenecks caused by extreme floods and droughts on adult fish assemblage; and (2) evaluating the appropriateness of commercial fisheries statistics in testing the habitat bottleneck concept. Time series analyses of the data were first tested for autocorrelations and then classified using the CHAID (Chi-squared Automatic Interaction Detector) and C&RT (Classification and Regression Trees) algorithms. The significant environmental predictors revealed by these segmentation procedures were used in cross-correlations with various time series of fisheries yields. No single hydraulic flood parameter was significantly correlated with fisheries yield but two drought parameters were. The strongest predictor of native fish species was the minimum discharge during the spawning season (March to June). Although total fisheries yield typically increased in years with low flows, probably because of higher catch efficiencies, the yields of pike and pikeperch significantly decreased in the following two years. By comparison, significantly higher catches of pike, perch, asp, burbot, and ide were recorded in the three years following periods of sustained higher base flows. Our findings suggest that habitat bottleneck effects on fish assemblages have an important role in influencing fish community structure and do require further study. Information on habitat bottlenecks will contribute to the setting of ecological flow requirements and sustainable fisheries in large rivers systems.

The general purpose of this work is to examine the relative ability of some well-selected zeolitic materials for the reduction of HC emissions generated within the Diesel "cold-start" period, i.e. when the work temperature of the Diesel Oxidation Catalyst (DOC) has not been reached. More peculiarly, this study is focused on the chemical, textural and structural parameters of zeolites influent on the elimination, namely by adsorption, of unburnt HC (propene, toluene and decane) in presence of potential inhibitors (H 2 O, CO, NO). Simulated "cold-start" conditions consisted in the rapid heating of the pre-treated zeolite sorbent/catalyst under the whole gas mixture from 35 to 530 • C. The quantity of trapped HC and those converted to CO x by oxidation were measured in function of the temperature, as well as the amount of NO x converted by the HC-SCR reaction. The interpretation of the HC emission profiles in close relation with the porous and acidic (through FTIR of adsorbed pyridine) properties of the corresponding zeolites allowed to gain insight onto the relative contributions of the pore topology, the pore size and the acid strength. For some selected zeolites, several consecutive cold-start cycles were performed in order to assess their stability.

The impact of ultrasound (US) on membrane filtration and cleaning were studied and compared at various operating parameters of nominal pore sizes of 10 and 100 kDa membrane, trans-membrane pressure (TMP) of 100 and 140 kPa, and US frequencies of 20 kHz and 40 kHz. An average of 15%–20% increase of permeability was observed when US (20 kHz) was applied to assist membrane filtration on 10 kDa membrane and 100 kPa trans-membrane pressure (TMP). However, an insignificant improvement was observed in the case of larger pore size membrane at higher TMP (140 kPa). US also augmented the membrane cleaning process effectively. Lower frequency 20 kHz US exhibited a higher flux recovery (>90%) than the high frequency 40 kHz (59%) using the 10 kDa pore size membrane with US-assisted membrane cleaning. Important factors influencing optimization of US effectiveness lie heavily on its configuration and operation. The experimental results as supported with SEM images demonstrate that US-assisted filtration and cleaning are most effective when membrane pore size, US frequency, and TMP are lower.

Industrial port cities are essential components in a society dependant on fossil fuels and low cost energy. In the global move towards a low-carbon society, industrial port cities are emblematic of complex and integrated socio-ecological systems, which are experiencing transition processes related to interactions between bio-geo-physical components and governance. Using a socio-ecological system framework, this article provides insights into innovative regional eco-industrial development strategies for moving toward a low-carbon future in industrial port areas. Based on three case studies (Marseille-Fos in France, Ningbo in China, and Ulsan in South Korea), our analysis focuses on the changing relationships between energy, land cover, time use, and governance. The historical socio-ecological transition of industrial port cities is described as a stepwise process of spatial and functional disconnection/connection of port industrial complexes, which decouple/combine the port city's metabolism from local resources. We highlight the impacts of globalization on port-city socio-ecological trends, describing the effects of the integration of port cities into global economic processes, the impact of global awareness on global environmental changes, and the accelerating pace of change. We compare low-carbon strategies, revealing similarities in terms of conversion toward low carbon sources and growing connectedness and functional diversity of port-industrial systems.

1] Hyporheic flow results from the interaction between streamflow and channel morphology and is an important component of stream ecosystems because it enhances water and solute exchange between the river and its bed. Hyporheic flow in pool-riffle channels is particularly complex because of three-dimensional topography that spans a range of partially to fully submerged conditions, inducing both static and dynamic head variations. Hence, these channels exhibit transitional conditions of streambed pressure and hyporheic flow compared to previous studies of fully submerged, two-dimensional bed forms. Here, we conduct a series of three-dimensional simulations to investigate the effects of bed topography, depth of alluvium, and stream discharge on hyporheic flow in pool-riffle reaches with variable bed form submergence, and we propose three empirical formulae to predict the mean depth of hyporheic exchange and characteristic values of the residence time distribution (mean and standard deviation). Hyporheic exchange is predicted with a three-dimensional pumping model, and hyporheic flow is modeled as a Darcy flow. We find that the hyporheic residence time is well approximated by a lognormal distribution for both partially and entirely submerged pool-riffle topography, with the parameters of the distribution defined by the mean and variance of the log-transformed residence time. Depth of alluvium has a substantial effect on hyporheic flow when alluvial depth is less than a third of the bed form wavelength for the conditions examined.

Interfacial interactions, namely interfacial tension, wettability, capillarity and interfacial mass transfer are known to govern fluid distribution and behavior in porous media. Therefore the interfacial interactions between CO 2 , brine and oil and/or gas reservoirs have a significant influence on the effectiveness of any CO 2 storage operations. However, data and knowledge of interfacial properties in storage conditions are scarce. This issue becomes particularly true in the case of deep saline aquifers where limited, economically driven, data collection and archiving are available. In this paper, we present a complete set of brine-CO 2 interfacial tension data at pressure, temperature and salinity conditions, representative of a CO 2 storage operation. A semi-empirical correlation is proposed to calculate the interfacial tension from the experimental data. Wettability is studied at pore scale, using glass micromodels in order to track fluids distribution as a function of the thermodynamic properties and wettability conditions for water-CO 2 systems. With this approach, we show that, in strongly hydrophilic porous media, the CO 2 does not wet the solid surface whereas; if the porous media has less hydrophilic properties the CO 2 significantly wets the surface.

The flow regimes of temperate large lowland rivers are manipulated to provide various services for society. Most water policy decisions are based on economic considerations, with little or no consideration toward fish conservation and fisheries. The prerequisite for a stronger implementation of these interests in water policy decisions is the development of appropriate tools for assessing the adequate flow needed to protect fish diversity and fisheries resources.

ABSTRACT
Nowadays, drainage networks, whether that was wastewater or storm water drainage networks are considered as one of the necessary infrastructure basics in modern cities. This research is focusing on planning and designing one drainage network “for a dual purpose” instead of the two networks that used one for wastewater and the other one for rainwater drainage, as they are called separated Drainage networks. Therefore, this network is working on wastewater and on the rainwater drainage on the same time. That reduces the cost by reducing amount of excavations and number of the pipes as well the wages for the workers who work on that project. This network would be perfect in Arab countries like Iraq because the amount of the rainfall is not that much and it happens only on the winter season for almost two or three months, not like the other western countries or Australia.
This research is following the global standardization in finding the optimal way of the designing a network such as finding the pipe slope and velocity of the water inside the pipes. Also, to compare it with minimum and the maximum velocity permitted, as well as finding the discharges and levels of pipes’ places in trenches and that depending on essential principles of designing of the network.
The research also includes the planning, designing and drawing a typical longitudinal sections for the Arab city and to be considered as a model that could be used for the planning and designing for any other cities according to the least possible cost.
All in all, the most important characteristic of this research is to adopt the discharging of more than a pipe in one direction within the inspection room so as to minimize the amount of excavation and reduce the diameters of the large pipes. For example, instead of choosing a pipe with a large diameter we can use two or more pipes with less diameter and that consider as a special feature worthwhile when you do not desire to the use of large diameters or the unavailability of that kind of pipes.

In assessments of the environmental impacts of waste management, life-cycle assessment (LCA) helps expanding the perspective beyond the waste management system. This is important, since the indirect environmental impacts caused by surrounding systems, such as energy and material production, often override the direct impacts of the waste management system itself. However, the applicability of LCA for waste management planning and policy-making is restricted by certain limitations, some of which are characteristics inherent to LCA methodology as such, and some of which are relevant specifically in the context of waste management. Several of them are relevant also for other types of systems analysis. We have identified and discussed such characteristics with regard to how they may restrict the applicability of LCA in the context of waste management. Efforts to improve LCA with regard to these aspects are also described. We also identify what other tools are available for investigating issues that cannot be adequately dealt with by traditional LCA models, and discuss whether LCA methodology should be expanded rather than complemented by other tools to increase its scope and applicability.

Recirculating aquaculture systems may require an internal disinfection process to control population growth of pathogens and heterotrophic bacteria. Ozonation and ultraviolet (UV) irradiation are two technologies that have been used to treat relatively large aquaculture flows, including flows within freshwater systems that recirculate water. The objective of the present study was to evaluate the effectiveness of ozone application alone or ozone application followed by UV irradiation to reduce abundance of heterotrophic and total coliform bacteria in a water reuse system. Results indicate that when only ozone was applied at dosagesdefined by the product of the ozone concentration times the mean hydraulic residence time (Ct) -that ranged from 0.10 to 3.65 min mg/L, the total heterotrophic bacteria counts and total coliform bacteria counts in the water exiting the contact basin were reduced to, respectively, 3-12 cfu/mL (1.1-1.6 LOG 10 reduction) and 2-18 cfu/100 mL (1.9-3.1 LOG 10 reduction). Bacteria inactivation appeared to be just as effective at the lowest ozone ct dosage (i.e., 0.1 mg/L ozone after a 1 min contact time) as at the highest ozone ct dosage (i.e., 0.2 mg/L ozone after a 16.6 min contact time). As with our previous research on UV inactivation of bacteria, we hypothesize that the recirculating system provided a selection process that favors bacteria that embed within particulate matter or that form bacterial aggregates that provides shielding from oxidation. However, when ozonation was followed by UV irradiation, the total heterotrophic bacteria counts and total coliform bacteria counts in the water exiting the UV irradiation unit were reduced to, respectively, 0-4 cfu/mL (1.6-2.7 LOG 10 reduction) and 0-3 cfu/100 mL (2.5-4.3 LOG 10 reduction). Thus, combining ozone dosages of only 0.1-0.2 min mg/L with a UV irradiation dosage of approximately 50 mJ/cm 2 would consistently reduce bacteria counts to near zero. These findings were orders of magnitude lower than the bacteria counts measured in the system when it was operated without disinfection or with UV irradiation alone. These findings indicate that combining ozonation and UV irradiation can effectively disinfect recirculating water before it returns to the fish culture tank(s). #

Considerably long periods of time are required to measure soil-water characteristic curves using conventional equipment such as pressure plate apparatus or a Tempe cell. A commercially available, small-scale medical centrifuge with a swinging type rotor assembly was used to measure the soil-water characteristic curves on statically compacted, fine-grained soil specimens. A specimen holder was specially designed to obtain multiple sets of water content versus suction data for measuring the soil-water characteristic curve at a single speed of rotation of the centrifuge. The soil-water characteristic curves were measured for three different types of fine-grained soils. The three soils used in the study were processed silt (liquid limit, wL = 24%; plasticity index, Ip = 0; and clay = 7%), Indian Head till (wL = 35.5%, Ip = 17%, and clay = 30%), and Regina clay (wL = 75.5%, Ip = 21%, and clay = 70%). The soil-water characteristic curves for the above soils were measured in 0.5, 1, and 2 ...

1] This paper assesses global water stress at a finer temporal scale compared to conventional assessments. To calculate time series of global water stress at a monthly time scale, global water availability, as obtained from simulations of monthly river discharge from the companion paper, is confronted with global monthly water demand. Water demand is defined here as the volume of water required by users to satisfy their needs. Water demand is calculated for the benchmark year of 2000 and contrasted against blue water availability, reflecting climatic variability over the period 1958-2001. Despite the use of the single benchmark year with monthly variations in water demand, simulated water stress agrees well with long-term records of observed water shortage in temperate, (sub)tropical, and (semi)arid countries, indicating that on shorter (i.e., decadal) time scales, climatic variability is often the main determinant of water stress. With the monthly resolution the number of people experiencing water scarcity increases by more than 40% compared to conventional annual assessments that do not account for seasonality and interannual variability. The results show that blue water stress is often intense and frequent in densely populated regions (e.g., India, United States, Spain, and northeastern China). By this method, regions vulnerable to infrequent but detrimental water stress could be equally identified (e.g., southeastern United Kingdom and northwestern Russia).

Several global corporations have been severely criticized by different lobbying groups for the impact of their operations on the natural environment and on the local communities. Because corporate operations cannot be studied in isolation but rather as a part of a large network often referred to as a supply chain, this paper investigates the potential link between supply chain characteristics and sustainable development at the country level. In particular, the linkage between supply chain strength, generally defined as the number and quality of the suppliers and customers in a country, and the three dimensions of sustainable development namely environmental performance, corporate environmental practices, and social sustainability is assessed. Using archival data from The Global Competitiveness Report (2004)(2005) and the 2005 Environmental Sustainability Index, a statistical assessment of the linkage was conducted.

Palm kernel shell biochars (PKSB) ejected as residues from a gasifier have been used for solid fuel briquette production. With this approach, palm kernel shells can be used for energy production twice: first, by producing rich syngas during gasification; second, by compacting the leftover residues from gasification into high calorific value briquettes. Herein, the process parameters for the manufacture of PKSB biomass briquettes via compaction are optimized. Two possible optimum process scenarios are considered. In the first, the compaction speed is increased from 0.5 to 10 mm/s, the compaction pressure is decreased from 80 Pa to 40 MPa, the retention time is reduced from 10 s to zero, and the starch binder content of the briquette is halved from 0.1 to 0.05 kg/kg. With these adjustments, the briquette production rate increases by more than 20-fold; hence capital and operational costs can be reduced and the service life of compaction equipment can be increased. The resulting product satisfactorily passes tensile (compressive) crushing strength and impact resistance tests. The second scenario involves reducing the starch weight content to 0.03 kg/kg, while reducing the compaction pressure to a value no lower than 60 MPa. Overall, in both cases, the PKSB biomass briquettes show excellent potential as a solid fuel with calorific values on par with good-quality coal. Abbreviations: CHNS: carbon, hydrogen, nitrogen, sulfur; FFB: fresh fruit bunch(es); HHV: higher heating value [J/kg]; LHV: lower heating value [J/kg]; PKS: palm kernel shell(s); PKSB: palm kernel shell biochar(s); POME: palm oil mill effluent; RDF: refuse-derived fuel; TGA: thermogravimetric analysis ARTICLE HISTORY Nomenclature Roman D diameter of sample [m] F maximum force applied to break sample in tensile crushing strength test [N] H height of sample [m] Greek s radial tensile crushing strength [N/m 2 ]

To predict the performance of an aquifer thermal energy storage system, an understanding of the system's hydrothermal behavior is needed. One possibility is to run a detailed numerical simulation of the system. However, for a single-well system in which fluid flow is limited to steady radial flow, a characterization scheme based on a set of four dimensionless parameter groups allows production temperatures and energy recovery factors to be read from graphs. The assumption of radial fluid flow is valid when buoyancy flow can be neglected and a well is fully screened in a horizontal aquifer which is confined above and below by impermeable layers. Criteria for little buoyancy flow include a low permeability or vertically stratified aquifer, a small temperature difference between injected and ambient water. and short cycle leneth The ha.•ie enerov tranannrt ., ,.., ........ •,.• ....... r layer system with steady radial fluid flow in the aquifer are nondimensionalized to derive the key parameter groups. Next a numerical model which calculates the heat transfer in the aquifer and confining layers for an injection-storage-production cycle is run for a range of values of these groups. The calculated production temperatures and energy recovery factors are then presented graphically as a function of the parameter groups. Comparisons between results of field experiments and recovery factors read from the graphs show good agreement. ATES cycl• [Tsang eta!., 1977; Fabris et al., 1977]. Recently, Sauty et al. [1980a] have studied the thermal behavior of a simplified single-well ATES system in terms of , a set of dimensionless groups. A few heat storage field experiments in either confined

Interannual climatic and hydrologic variability has been substantial during the past decades in many regions. While climate variability and its impacts on precipitation and soil moisture have been studied intensively, less is known on subsequent implications for global food production. In this paper we quantify effects of hydroclimatic variability on global "green" and "blue" water availability and demand in global agriculture, and thus complement former studies that have focused merely on long-term averages. Moreover, we assess some options to overcome chronic or sporadic water scarcity. The analysis is based on historical climate forcing data sets over the period 1977-2006, while demography, diet composition and land use are fixed to reference conditions (year 2000). In doing so, we isolate the effect of interannual hydroclimatic variability from other factors that drive food production. We analyse the potential of food production units (FPUs) to produce a reference diet for their inhabitants (3000 kcal cap −1 day −1 , with 80 % vegetal food and 20 % animal products). We applied the LPJmL vegetation and hydrology model to calculate the variation in green-blue water availability and the water requirements to produce that very diet. An FPU was considered water scarce if its water availability was not sufficient to produce the diet (i.e. assuming food self-sufficiency to estimate dependency on trade from elsewhere). We found that 24 % of the world's population lives in chronically water-scarce FPUs (i.e. water is scarce every year), while an additional 19 % live under occasional water scarcity (water is scarce in some years). Among these 2.6 billion people altogether, 55 % would have to rely on international trade to reach the reference diet, while for 24 % domestic trade would be enough. For the remaining 21 % of the population exposed to some degree of water scarcity, local food storage and/or intermittent trade would be enough to secure the reference diet over the occasional dry years. Southern Oscillation (ENSO). Furthermore, meteorological

The vast majority of the world's rivers are now being tapped for their water supplies, yet only a tiny fraction of these rivers are protected by any sort of environmental flow standard. While important advances have been made in reducing the cost and time required to determine the environmental flow needs of both individual rivers and types of rivers in specific geographies, it is highly unlikely that such approaches will be applied to all, or even most, rivers within the forseeable future. As a result, the vast majority of the planet's rivers remain vulnerable to exploitation without limits. Clearly, there is great need for adoption of a "presumptive standard" that can fill this gap. In this paper we present such a presumptive standard, based on the Sustainability Boundary Approach of Richter (2009) which involves restricting hydrologic alterations to within a percentage-based range around natural or historic flow variability. We also discuss water management implications in applying our standard. Our presumptive standard is intended for application only where detailed scientific assessments of environmental flow needs cannot be undertaken in the near term.

Effects of activated carbon in a carbon-coated alumina (CCA) support, active phase morphology and its composition of Ni 6 -PW 12 S/C x /Al 2 O 3 catalysts in hydrotreating of model compounds were studied. The catalysts were synthesized using 12-tungstophosphoric heteropolyacid, nickel citrate and CCA and characterized with multiple methods: N 2 physisorption, X-ray powder diffraction, H 2 temperature programmed reduction, temperature-programmed desorption of ammonia, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The catalytic properties were determined using a fixed-bed microreactor in hydrotreating of dibenzothiophene, naphthalene and quinoline. It was found that with the increase of carbon content in the CCA up to 5 wt.%, reducible reactivity, sulphidation degree, average length and stacking number of WS 2 crystallites in the catalysts increased. Observed changes can be explained by weakening interaction between metal oxide species and carbon-coated support. Full promotion of the NiWS edges by nickel was achieved in the catalysts supported on the CCA with carbon content equal 0.3 wt.% and more. Activities of the catalysts in dibenzothiophene hydrodesulphurization, naphthalene hydrogenation and quinoline hydrodenitrogenation were essentially depended on the carbon content in the CCA-support. Ni 6 -PW 12 S/C 1 /Al 2 O 3 catalyst showed maximal conversions of the substrates in studied reactions. This result was achieved due to an optimal balance between turnover frequency value of the active sites and their content.

1] The interest about the exchange of water between streams and aquifers has been increasing among the hydrologic community because of the implications of the exchange of heat, solutes, and colloids for the water quality of aquatic environments. Unfortunately, our understanding of the relevance of the exchange processes is limited by the great number of coupled hydrological and geomorphological factors that interact to generate the complex spatial patterns of exchange. In this context, the present work presents a mathematical model for the surface-subsurface exchange through the streambed of a meandering stream. The model is based on the linearization of the equations that govern the hydrodynamics and the morphodynamics of the system, and it provides a first-order analytical solution of the coupled flow field of both the surface and the subsurface flows. The results show that stream curvature determines a characteristic spatial pattern of hyporheic exchange, with water upwelling and downwelling concentrated near the stream banks. The exchange can drive surface water deep into the sediments, thus keeping deep alluvium regions connected with the stream. The relationships between hyporheic exchange flux and the geometrical and hydrodynamical properties of the stream-aquifer system are also investigated.

The aim of the study was to obtain high quality biodiesel production from a microalga Chlorella protothecoids through the technology of transesterification. The technique of metabolic controlling through heterotrophic growth of C. protothecoides was applied, and the heterotrophic C. protothecoides contained the crude lipid content of 55.2%. To increase the biomass and reduce the cost of alga, corn powder hydrolysate instead of glucose was used as organic carbon source in heterotrophic culture medium in fermenters. The result showed that cell density significantly increased under the heterotrophic condition, and the highest cell concentration reached 15.5 g L −1 . Large amount of microalgal oil was efficiently extracted from the heterotrophic cells by using n-hexane, and then transmuted into biodiesel by acidic transesterification. The biodiesel was characterized by a high heating value of 41 MJ kg −1 , a density of 0.864 kg L −1 , and a viscosity of 5.2 × 10 −4 Pa s (at 40 • C). The method has great potential in the industrial production of liquid fuel from microalga.

A conceptual, continuous time model called SWAT (Soil and Water Assessment Tool) was developed to assist water resource managers in assessing the impact of management on water supplies and nonpoint source pollution in watersheds and large river basins. The model is currently being utilized in several large area projects by EPA, NOM, NRCS and others to estimate the off-site impacts of climate and management on water use, nonpoint source loadings, and pesticide contamination. Model development, operation, limitations, and assumptions are discussed and components of the model are described. In Part II, a GIS input/output interface is presented along with model validation on three basins within the Upper Trinity basin in Texas.

Currently used in many countries in the world, vetiver grass (Vetiveria zizanioides) applications include soil and water conservation systems in agricultural environment, slope stabilization, mine rehabilitation, contaminated soil and saline land remediation, as well as wastewater treatment. The root system morphology of vetiver was investigated in a small plantation growing on abandoned marl terraces in southern Spain. Root distribution with depth, laterally from the plant, as well as root parameters such as root diameter and tensile strength were also investigated. The profile wall method combined with the block excavation showed that the vetiver grass grows numerous positively gravitropic roots of more or less uniform diameter. These were generally distributed in the uppermost soil horizon closer to the culm base. In situ shear test on blocks of soil permeated with vetiver roots were carried out and showed a greater shear strength resistance than the samples of non vegetated soil. The root reinforcement measured in situ was comparable to the one predicted by the perpendicular root reinforcement model. The stability of a modelled terraced slope planted with vetiver was marginally greater than the one of a nonvegetated slope. A local instability on one terrace can have a detrimental effect on the overall stability of the terraced slope.

Construction and demolition waste is one of the important category of solid waste. Many recreational and building projects contribute towards generation of ample quantity of waste produced on these respective sites. Reutilisation of the construction and demolition waste can be very beneficial in terms of various managing and operational parameters on a construction site. This paper emphasises upon study ofassessment of reutilization of various categorical waste from constructional site situated at different geographical areas. Numerous types of waste generated from these respective sites are taken into consideration and their reutilisation on the same site is focussed which resulted in reducing cost, labour work and wastage of the materials. By-product formation from the reutilisation of waste generated from these types of constructional arena is being focussed upon. Further recommendations in terms of the future scope of the study are given at the end of the paper.

An efficient and new but non-intrusive method to detect the fluctuation in gear load may be the motor current signature analysis (MCSA). In this paper, a multi-stage transmission gearbox (with and without defects) has been studied in order to replace the conventional vibration monitoring by MCSA. It has been observed through FFT analysis that low frequencies of the vibration signatures have sidebands across line frequency of the motor current whereas high frequencies of vibration signature are difficult to be detected. Hence, discrete wavelet transform (DWT) is suggested to decompose the current signal, and FFT analysis is carried out with the decomposed current signal to trace the sidebands of the high frequencies of vibration

Wind energy is one among the most promising renewable energy sources, and hence there is fast growth of wind energy farm implantation over the last decade, which is expected to be even faster in the coming years. Wind turbine blades are complex structures considering the different scientific fields involved in their study. Indeed, the study of blade performance involves fluid mechanics (aerodynamic study), solids mechanics (the nature of materials, the type of solicitations …), and the fluid coupling structure (IFS). The scope of the present work is to investigate the mechanical performances and structural integrity of a large offshore wind turbine blade under critical loads using blade element momentum. The resulting pressure was applied to the blade by the use of a user subroutine “DLOAD” implemented in ABAQUS finite element analysis software. The main objective is to identify and predict the zones which are sensitive to damage and failure as well as to evaluate the potential of c...

Megaprojects are large, they are constantly growing ever larger, and more and more are being built in what has been called the biggest investment boom in history. This chapter serves as an introduction to megaprojects, and to The Oxford Handbook of Megaproject Management. First, megaprojects are defined and the size of the global megaprojects business is estimated. Second, drivers of the megaproject boom are identified, including monumentalism and the technological sublime. Third, ten things you must know about megaprojects are detailed, from their tendency to suffer from uniqueness bias to their overexposure to black-swan events. Fourth, the "iron law of megaprojects" is identified as a main challenge to megaproject management: "Over budget, over time, under benefits, over and over again." Finally, the main structure of the Handbook is set out as covering the what, the why, and the how of megaproject management, in terms of the challenges, causes, and cures that students of megaprojects must decipher to better understand and better manage megaprojects.

The main objective of this work was the design of a high efficiency centrifugal surface aerator for fishponds. The proposed system has been designed to be used with photovoltaic panels as an energy supply. The work is presented in three papers, of which this is the first part. The objective was reached through a theoretical design of the rotor using the traditional mass transfer equations and the mechanical approach using the superficial similarities of aerators to axial flow pumps. A total of 23 different rotor configurations were tested. The configurations were defined by the type of propeller, the inlet and exit angles of the blades and the rotor's immersion percentage. Dimensional analyses was used to find the equations that describes the aerator's behavior.

TiO 2 polycrystalline sub-micron fibers can be used as photocatalysts for the degradation of a variety of organic molecules. Here we report on the optimization of these fibers for decontaminating pharmaceutical agents in aqueous medical waste streams. Mixed-phase TiO 2 fibers have been prepared via a sol-gel technique followed by electrospinning and calcination. By adjusting the calcination temperature, the rutile phase fraction in TiO 2 fibers can be tuned relative to the anatase phase from 0% to 100%. The effect of rutile phase fraction on grain size and specific surface area as well as their subsequent influences on the photocatalytic activity was investigated. An optimal grain size in post-calcined TiO 2 fibers was found to be critical to balance the e-/h + volume recombination, surface recombination rate, and charge diffusion rate. The photocatalytic activities of the post-calcined TiO 2 fibers with different rutile fractions were measured by monitoring the decreasing concentration of phenazopyridine in aqueous solution under UV illumination using UV-Vis absorption spectroscopy. Post-calcined TiO 2 fibers composing of 38 wt% rutile and 62 wt% anatase exhibited the highest initial degradation rate constant of 0.044 min-1. This optimal photocatalytic activity can be attributed to the combined influences of the fibers' phase composition, surface area and grain size.

The implementation of increasingly stringent standards for the discharge of waste into the environment, as well as the increase in cost of habitual disposal or treatment options, has motivated the development of different processes for the treatment and disposal of wastes. Solid waste may seem to be the most ordinary forms of wastes, but they could be responsible for many problems such as spread of diseases and emission of green house gases. Over the years, solid waste disposal was a neglected issue as these wastes were simply dumped on land in the outside of the city. Unscientific disposal of solid wastes causes an adverse impact on all components of the environment and human health. Transformation of wastes and pollutants are classified as being chemical or biological in nature. Micro-organisms are the agents which bring about the conversion of these wastes into useful products like fuel gases, fuel alcohol and also compost which can be used as manure. Among different bioconversion of solid waste composting appears to be a safe form of treatment of solid waste and the reclamation of the nutrients containing in them. During the last few years, composting by mushroom fungi has gained wide acceptance as a key component of integrated solid waste management. It has been promoted as an eco-friendly and sustainable solution to urban waste management. It encourages the production of beneficial microorganism (mainly mushroom fungi) which in turn breaks down organic matter to create humus. Humus, a rich nutrient filled material, increase the nutrient content on soils and helps soil to retain moisture. Addition to this mushrooms directly utilize bioconversion of solid wastes generated from industry and agriculture into edible biomass, which could also be regarded as a functional food or as a source of drugs and pharmaceuticals.

The book points out that rural regions need proper attention at the global level concerning solid waste management sector where bad practices and public health threats could be avoided through traditional and integrated waste management
routes. Solid waste management in rural areas is a key issue in developing and transitioning countries due to the lack of proper waste management facilities and services. The book further examines, on the one hand, the main challenges in the development of reliable waste management practices across rural regions and, on the other hand, the concrete solutions and the new opportunities across the world in dealing with municipal and agricultural wastes. The book provides useful information for academics, various professionals, the members of civil society, and national and local authorities.

This standard is issued under the fixed designation A380/A380M; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.

Efforts to conserve stream and river biota could benefit from tools that allow managers to evaluate landscape-scale changes in species distributions in response to water management decisions. We present a framework and methods for integrating hydrology, geographic context and metapopulation processes to simulate effects of changes in streamflow on fish occupancy dynamics across a landscape of interconnected stream segments. We illustrate this approach using a 482 km 2 catchment in the southeastern US supporting 50 or more stream fish species. A spatially distributed, deterministic and physically based hydrologic model is used to simulate daily streamflow for sub-basins composing the catchment. We use geographic data to characterize stream segments with respect to channel size, confinement, position and connectedness within the stream network. Simulated streamflow dynamics are then applied to model fish metapopulation dynamics in stream segments, using hypothesized effects of streamflow magnitude and variability on population processes, conditioned by channel characteristics. The resulting time series simulate spatially explicit, annual changes in species occurrences or assemblage metrics (e.g. species richness) across the catchment as outcomes of management scenarios. Sensitivity analyses using alternative, plausible links between streamflow components and metapopulation processes, or allowing for alternative modes of fish dispersal, demonstrate large effects of ecological uncertainty on model outcomes and highlight needed research and monitoring. Nonetheless, with uncertainties explicitly acknowledged, dynamic, landscape-scale simulations may prove useful for quantitatively comparing river management alternatives with respect to species conservation. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

The conclusions of numerous stream restoration assessments all around the world are extremely clear and convergent: there has been insufficient appropriate monitoring to improve general knowledge and expertise. In the specialized field of instream flow alterations, we consider that there are several opportunities comparable to full-size experiments. Hundreds of water management decisions related to instream flow releases have been made by government agencies, native peoples, and non-governmental organizations around the world. These decisions are based on different methods and assumptions and many flow regimes have been adopted by formal or informal rules and regulations. Although, there have been significant advances in analytical capabilities, there has been very little validation monitoring of actual outcomes or research related to the response of aquatic dependent species to new flow regimes. In order to be able to detect these kinds of responses and to better guide decision, a general design template is proposed. The main steps of this template are described and discussed, in terms of objectives, hypotheses, variables, time scale, data management, and information, in the spirit of adaptive management. The adoption of such a framework is not always easy, due to differing interests of actors for the results, regarding the duration of monitoring, nature of funding and differential timetables between facilities managers and technicians. Nevertheless, implementation of such a framework could help researchers and practitioners to coordinate and federate their efforts to improve the general knowledge of the links between the habitat dynamics and biological aquatic responses.

The globally escalating thyroid nodule incidence rates may be only partially ascribed to better diagnostics, allowing for the assessment of environmental risk factors on thyroid disease. Endocrine disruptors or thyroid-disrupting chemicals (TDC) like bisphenol A, phthalates, and polybrominated diphenyl ethers are widely used as plastic additives in consumer products. This comprehensive review studied the magnitude and uncertainty of TDC exposures and their effects on thyroid hormones for sensitive subpopulation groups like pregnant women, infants, and children. Our findings qualitatively suggest the mixed, significant (α = 0.05) TDC associations with natural thyroid hormones (positive or negative sign). Future studies should undertake systematic meta-analyses to elucidate pooled TDC effect estimates on thyroid health indicators and outcomes.