A study of the effect of N2 reservoir temperature on a 16 μm CO2-N2 downstream-mixing gasdynamic laser

A study of the effect of N2 reservoir temperature on the small-signal gain in a downstream-mixing 16 μm CO2-N2 GDL is presented. It is shown that the small-signal gain decreases with the increase of N2 reservoir temperature. The conditions for reversing this trend are discussed and the results are presented in the form of graphs.

The upper respiratory tract is a natural reservoir of haemolytic Mannheimia species associated with ovine mastitis

Lamb suckling has been suggested to be an important way of infecting a ewe's udder with different bacteria, including Mannheimia haemolytica. To test the potential role of lambs in transferring Mannheimia species to the ewe’s udder, the restriction endonuclease cleavage patterns of isolates obtained from nasopharyngeal swabs were compared with those obtained from cases of mastitis. Sterile cotton swabs were used to collect nasopharyngeal samples from 50 ewes and 36 lambs from three flocks. M. haemolytica and Mannheimia glucosida as well as haemolytic Mannheimia ruminalis-like organisms were detected in the upper respiratory tract of lambs and ewes. Comparison of the restriction endonuclease cleavage patterns of the isolates suggested that the M. haemolytica isolates obtained from different milk samples from ewes with mastitis were more clonal than those obtained from the nasal swabs. However, some nasal isolates within both Mannheimia species had restriction endonuclease cleavage patterns identical to those obtained from milk samples from ewes with mastitis, indicating that lambs may have a role in transferring these organisms to the udder. More clonality was observed between the M. glucosida isolates than between M. haemolytica isolates.

Free vibrations of a reservoir-foundation system

The natural frequencies of a reservoir-foundation system are calculated by treating the foundation as a system of linear springs with inertia. The reservoir is treated as consisting of compressible liquid, and the influence of waves at the free surface is included. It is shown that the natural frequencies decrease monotonically as the depth of foundation participating in the motion increases. The influence of waves at the reservoir surface is negligible for the cases normally occurring in practice. It is also shown that the wavelength of motion along the reservoir has no influence on the frequencies when the foundation depth is large compared to the reservoir depth.

Replacement of water on a steel substrate by a surrounding oil reservoir

With an objective to replace a water droplet from a steel surface by oil we study here the impact of injecting a hydrophilic/lipophilic surfactant into the droplet or into the surrounding oil reservoir. Contact angle goniometery, Grazing angle FTIR spectroscopy and Atomic force microscopy are used to record the oil/water interfacial tension, surface energetics of the substrate under the oil and water phases as well as the corresponding physical states of the substrates. Such energetics reflect the rate at which the excess surfactant molecules accumulate at the water/oil interface and desorb into the phases. The molecules diffuse into the substrate from the phases and build up specific molecular configurations which, with the interfacial tension, control the non-equilibrium progress of and the equilibrium status of the contact line. The study shows that the most efficient replacement of water by the surrounding oil happens when a surfactant is sparingly soluble in the supplier oil phase and highly soluble in the recipient water phase.

Optimal Reservoir Operation for Flood Control Using Folded Dynamic Programming

Folded Dynamic Programming (FDP) is adopted for developing optimalnreservoir operation policies for flood control. It is applied to a case study of Hirakud Reservoir in Mahanadi basin, India with the objective of deriving optimal policy for flood control. The river flows down to Naraj, the head of delta where a major city is located and finally joins the Bay of Bengal. As Hirakud reservoir is on the upstream side of delta area in the basin, it plays an important role in alleviating the severity of the flood for this area. Data of 68 floods such as peaks of inflow hydrograph, peak of outflow from reservoir during each flood, peak of flow hydrograph at Naraj and d/s catchment contribution are utilized. The combinations of 51, 54, 57 thousand cumecs as peak inflow into reservoir and 25.5, 20, 14 thousand cumecs respectively as,peak d/s catchment contribution form the critical combinations for flood situation. It is observed that the combination of 57 thousand cumecs of inflow into reservoir and 14 thousand cumecs for d/s catchment contribution is the most critical among the critical combinations of flow series. The method proposed can be extended to similar situations for deriving reservoir operating policies for flood control.

Reservoir performance under uncertainty in hydrologic impacts of climate change

Relatively few studies have addressed water management and adaptation measures in the face of changing water balances due to climate change. The current work studies climate change impact on a multipurpose reservoir performance and derives adaptive policies for possible futurescenarios. The method developed in this work is illustrated with a case study of Hirakud reservoir on the Mahanadi river in Orissa, India,which is a multipurpose reservoir serving flood control, irrigation and power generation. Climate change effects on annual hydropower generation and four performance indices (reliability with respect to three reservoir functions, viz. hydropower, irrigation and flood control, resiliency, vulnerability and deficit ratio with respect to hydropower) are studied. Outputs from three general circulation models (GCMs) for three scenarios each are downscaled to monsoon streamflow in the Mahanadi river for two future time slices, 2045-65 and 2075-95. Increased irrigation demands, rule curves dictated by increased need for flood storage and downscaled projections of streamflow from the ensemble of GCMs and scenarios are used for projecting future hydrologic scenarios. It is seen that hydropower generation and reliability with respect to hydropower and irrigation are likely to show a decrease in future in most scenarios, whereas the deficit ratio and vulnerability are likely to increase as a result of climate change if the standard operating policy (SOP) using current rule curves for flood protection is employed. An optimal monthly operating policy is then derived using stochastic dynamic programming (SDP) as an adaptive policy for mitigating impacts of climate change on reservoir operation. The objective of this policy is to maximize reliabilities with respect to multiple reservoir functions of hydropower, irrigation and flood control. In variations to this adaptive policy, increasingly more weightage is given to the purpose of maximizing reliability with respect to hydropower for two extreme scenarios. It is seen that by marginally sacrificing reliability with respect to irrigation and flood control, hydropower reliability and generation can be increased for future scenarios. This suggests that reservoir rules for flood control may have to be revised in basins where climate change projects an increasing probability of droughts. However, it is also seen that power generation is unable to be restored to current levels, due in part to the large projected increases in irrigation demand. This suggests that future water balance deficits may limit the success of adaptive policy options. (C) 2010 Elsevier Ltd. All rights reserved.

Finnish cattle as reservoir of Campylobacter spp.

The reported incidence of human campylobacteriosis in Finland is higher than in most other European countries. A high annual percentage of sporadic infections is of foreign origin, although a notable proportion of summer infections is domestically acquired. While chickens appear to be a major source of campylobacters for humans in most countries, the prevalence of campylobacters is very low in chicken slaughter batches in Finland. Data on other potential animal reservoirs of human pathogenic campylobacters in Finland are scarce. Consequently, this study aimed to investigate the status of Finnish cattle as a potential source of thermophilic Campylobacter spp. and antibiotic-resistant Campylobacter jejuni for human sporadic campylobacter infections of domestic origin. A survey of the prevalence of thermophilic Campylobacter spp. in Finnish cattle studied bovine rectal faecal samples (n=952) and carcass surface samples (n=948) from twelve Finnish slaughterhouses from January to December 2003. The total prevalence of Campylobacter spp. in faecal samples was 31.1%, and in carcass samples 3.5%. Campylobacter jejuni, the most common species, was present in 19.5% of faecal samples and in 3.1% of carcasses. In addition to thermophilic Campylobacter spp., C. hyointestinalis ssp. hyointestinalis was present in bovine samples. The prevalence of campylobacters was higher among beef cattle than among dairy cattle. Using the enrichment method, the number of positive faecal samples was 7.5 times higher than that obtained by direct plating. The predominant serotypes of faecal C. jejuni, determined by serotyping with a set of 25 commercial antisera for heat-stable antigens (Penner), were Pen2 and Pen4-complex, which covered 52% of the samples. Genotyping with pulsed-field gel electrophoresis (PFGE) using SmaI restriction yielded a high diversity of C. jejuni subtypes in cattle. Determining the minimum inhibitory concentrations of ampicillin, enrofloxacin, erythromycin, gentamicin, nalidixic acid, and oxytetracycline among bovine C. jejuni isolates using a commercial broth microdilution method yielded 9% of isolates resistant to at least one of the antimicrobials examined. No multiresistant isolates were found among the bovine C. jejuni strains. The study of the shedding patterns of Campylobacter spp. among three Finnish dairy cattle herds included the examination of fresh faecal samples and tank milk samples taken five times, as well as samples from drinking troughs taken once during the one-year study. The semiquantitative enrichment method detected C. jejuni in 169 of the 340 faecal samples, mostly at low levels. In addition, C. jejuni was present in one drinking trough sample. The prevalence between herds and sampling occasions varied widely. PFGE, using SmaI as restriction enzyme, identified only a few subtypes in each herd. In two 2 of the herds, two subtypes persisted throughout the sampling. Individual animals presented various shedding patterns during the study. Comparison of C. jejuni isolates from humans, chickens and cattle included the design of primers for four new genetic markers selected from completely sequenced C. jejuni genomes 81-176, RM1221 and NCTC 11168, and the PCR examination of domestic human isolates from southern Finland in 1996, 2002 and 2003 (n=309), chicken isolates from 2003, 2006 and 2007 (n=205), and bovine isolates from 2003 (n=131). The results revealed that bovine isolates differed significantly from human and chicken isolates. In particular, the - glutamyl transpeptidase gene was uncommon among bovine isolates. The PFGE genotyping of C. jejuni isolates, using SmaI and KpnI restriction enzymes, included a geographically representative collection of isolates from domestic sporadic human infections, chicken slaughter batches, and cattle faeces and carcasses during the seasonal peak of campylobacteriosis in the summer of 2003. The study determined that 55.4% of human isolates were indistinguishable from those of chickens and cattle. Temporal association between isolates from humans and chickens was possible in 31.4% of human infections. Approximately 19% of the human infections may have been associated with cattle. However, isolates from bovine carcasses and human cases represented different PFGE subtypes. In conclusion, this study suggests that Finnish cattle is a notable reservoir of C. jejuni, the most important Campylobacter sp. in human enteric infections. Although the concentration of these organisms in bovine faeces appeared to be low, excretion can be persistent. The genetic diversity and presence or absence of marker genes support previous suggestions of host-adapted C. jejuni strains, and may indicate variations in virulence between strains from different hosts. In addition to chickens, Finnish cattle appeared to be an important reservoir and possible source of C. jejuni in domestic sporadic human infections. However, sources of campylobacters may differ between rural and urban areas in Finland, and in general, the transmission of C. jejuni of bovine origin probably occurs via other routes than food.

Phytoplankton succession from 1968 to 1990 in the subarctic Lokka reservoir

Tiivistelmä: Kasviplanktonin kehitys vuosina 1968-1990 subarktisessa Lokan tekoaltaassa

Optimal reservoir operation for irrigation of multiple crops using genetic algorithms

This paper presents a genetic algorithm (GA) model for obtaining an optimal operating policy and optimal crop water allocations from an irrigation reservoir. The objective is to maximize the sum of the relative yields from all crops in the irrigated area. The model takes into account reservoir inflow, rainfall on the irrigated area, intraseasonal competition for water among multiple crops, the soil moisture dynamics in each cropped area, the heterogeneous nature of soils. and crop response to the level of irrigation applied. The model is applied to the Malaprabha single-purpose irrigation reservoir in Karnataka State, India. The optimal operating policy obtained using the GA is similar to that obtained by linear programming. This model can be used for optimal utilization of the available water resources of any reservoir system to obtain maximum benefits.

A modell of socially optimal hydro reservoir usage - yelding socially optimal outcomes in nordic electricity markets

An extensive electricity transmission network facilitates electricity trading between Finland, Sweden, Norway and Denmark. Currently most of the area's power generation is traded at NordPool, where the trading volumes have steadily increased since the early 1990's, when the exchange was founded. The Nordic electricity is expected to follow the current trend and further integrate with the other European electricity markets. Hydro power is the source for roughly a half of the supply in the Nordic electricity market and most of the hydro is generated in Norway. The dominating role of hydro power distinguishes the Nordic electricity market from most of the other market places. Production of hydro power varies mainly due to hydro reservoirs and demand for electricity. Hydro reservoirs are affected by water inflows that differ each year. The hydro reservoirs explain remarkably the behaviour of the Nordic electricity markets. Therefore among others, Kauppi and Liski (2008) have developed a model that analyzes the behaviour of the markets using hydro reservoirs as explanatory factors. Their model includes, for example, welfare loss due to socially suboptimal hydro reservoir usage, socially optimal electricity price, hydro reservoir storage and thermal reservoir storage; that are referred as outcomes. However, the model does not explain the real market condition but rather an ideal situation. In the model the market is controlled by one agent, i.e. one agent controls all the power generation reserves; it is referred to as a socially optimal strategy. Article by Kauppi and Liski (2008) includes an assumption where an individual agent has a certain fraction of market power, e.g. 20 % or 30 %. In order to maintain the focus of this thesis, this part of their paper is omitted. The goal of this thesis is two-fold. Firstly we expand the results from the socially optimal strategy for years 2006-08, as the earlier study finishes in 2005. The second objective is to improve on the methods from the previous study. This thesis results several outcomes (SPOT-price and welfare loss, etc.) due to socially optimal actions. Welfare loss is interesting as it describes the inefficiency of the market. SPOT-price is an important output for the market participants as it often has an effect on end users' electricity bills. Another function is to modify and try to improve the model by means of using more accurate input data, e.g. by considering pollution trade rights effect on input data. After modifications to the model, new welfare losses are calculated and compared with the same results before the modifications. The hydro reservoir has the higher explanatory significance in the model followed by thermal power. In Nordic markets, thermal power reserves are mostly nuclear power and other thermal sources (coal, natural gas, oil, peat). It can be argued that hydro and thermal reservoirs determine electricity supply. Roughly speaking, the model takes into account electricity demand and supply, and several parameters related to them (water inflow, oil price, etc.), yielding finally the socially optimal outcomes. The author of this thesis is not aware of any similar model being tested before. There have been some other studies that are close to the Kauppi and Liski (2008) model, but those have a somewhat different focus. For example, a specific feature in the model is the focus on long-run capacity usage that differs from the previous studies on short-run market power. The closest study to the model is from California's wholesale electricity markets that, however, uses different methodology. Work is constructed as follows.

Real-time multipurpose reservoir operation: a case study / Exploitation en temps reacuteel d'un reservoir agrave buts multiples: eacutetude d'un cas

A real-time operational methodology has been developed for multipurpose reservoir operation for irrigation and hydropower generation with application to the Bhadra reservoir system in the state of Karnataka, India. The methodology consists of three phases of computer modelling. In the first phase, the optimal release policy for a given initial storage and inflow is determined using a stochastic dynamic programming (SDP) model. Streamflow forecasting using an adaptive AutoRegressive Integrated Moving Average (ARIMA) model constitutes the second phase. A real-time simulation model is developed in the third phase using the forecast inflows of phase 2 and the operating policy of phase 1. A comparison of the optimal monthly real-time operation with the historical operation demonstrates the relevance, applicability and the relative advantage of the proposed methodology.

An integrated model for optimal reservoir operation for irrigation of multiple crops

An integrated model is developed, based on seasonal inputs of reservoir inflow and rainfall in the irrigated area, to determine the optimal reservoir release policies and irrigation allocations to multiple crops. The model is conceptually made up of two modules, Module 1 is an intraseasonal allocation model to maximize the sum of relative yields of all crops, for a given state of the system, using linear programming (LP). The module takes into account reservoir storage continuity, soil moisture balance, and crop root growth with time. Module 2 is a seasonal allocation model to derive the steady state reservoir operating policy using stochastic dynamic programming (SDP). Reservoir storage, seasonal inflow, and seasonal rainfall are the state variables in the SDP. The objective in SDP is to maximize the expected sum of relative yields of all crops in a year. The results of module 1 and the transition probabilities of seasonal inflow and rainfall form the input for module 2. The use of seasonal inputs coupled with the LP-SDP solution strategy in the present formulation facilitates in relaxing the limitations of an earlier study, while affecting additional improvements. The model is applied to an existing reservoir in Karnataka State, India.

Cross-polarization from the dipolar reservoir under the mismatched Hartmann-Hahn condition

Cross-polarization from the dipolar reservoir for a range of mismatched Hartmann-Hahn conditions has been considered. Experiment, in general, agrees with the dispersive Lorentzian behavior expected on the basis of quasi-equilibrium theory. It is observed that inclusion of additional mechanisms of polarization transfer lead to an improvment of the fit of the experimental results. The utility of extending the technique to the case of ordered long chain molecules, such as liquid crystals, for the measurement of the local dipolar field is also presented. (C) 2002 Elsevier Science (USA).

Modeling reservoir irrigation in uncertain hydrologic environment

In a detailed model for reservoir irrigation taking into account the soil moisture dynamics in the root zone of the crops, the data set for reservoir inflow and rainfall in the command will usually be of sufficient length to enable their variations to be described by probability distributions. However, the potential evapotranspiration of the crop itself depends on the characteristics of the crop and the reference evaporation, the quantification of both being associated with a high degree of uncertainty. The main purpose of this paper is to propose a mathematical programming model to determine the annual relative yield of crops and to determine its reliability, for a single reservoir meant for irrigation of multiple crops, incorporating variations in inflow, rainfall in the command area, and crop consumptive use. The inflow to the reservoir and rainfall in the reservoir command area are treated as random variables, whereas potential evapotranspiration is modeled as a fuzzy set. The model's application is illustrated with reference to an existing single-reservoir system in Southern India.

Swam Intelligent Based Inverse Model for Laboratory Double Reservoir Diffusion Experiments

Theoretical approaches are of fundamental importance to predict the potential impact of waste disposal facilities on ground water contamination. Appropriate design parameters are, in general, estimated by fitting the theoretical models to a field monitoring or laboratory experimental data. Double-reservoir diffusion (Transient Through-Diffusion) experiments are generally conducted in the laboratory to estimate the mass transport parameters of the proposed barrier material. These design parameters are estimated by manual parameter adjusting techniques (also called eye-fitting) like Pollute. In this work an automated inverse model is developed to estimate the mass transport parameters from transient through-diffusion experimental data. The proposed inverse model uses particle swarm optimization (PSO) algorithm which is based on the social behaviour of animals for finding their food sources. Finite difference numerical solution of the transient through-diffusion mathematical model is integrated with the PSO algorithm to solve the inverse problem of parameter estimation.The working principle of the new solver is demonstrated by estimating mass transport parameters from the published transient through-diffusion experimental data. The estimated values are compared with the values obtained by existing procedure. The present technique is robust and efficient. The mass transport parameters are obtained with a very good precision in less time