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Fuel sulfur emissions control areas have been established in a few marine coastal regions to reduce environmental impacts from combustion of high sulfur residual fuel oil (RFO). For example, in August of 2012, the U.S. began enforcing fuel sulfur limits on certain large commercial marine vessels up to 200 nautical miles (nm) of its coasts as part of a North American Emissions Control Area (NA-ECA), and in January of 2014, the U.S. began enforcing fuel sulfur limits on these vessels within up to 50 nm of Puerto Rico and the U.S. Virgin Islands as part of the U.S. Caribbean Sea ECA (USCAR-ECA). This work evaluates ECA effectiveness at reducing PM2.5 from combustion of RFO by using both spatial analysis, comparing PM2.5 source apportionment at IMPROVE monitoring sites largely impacted by air from either inside or outside of an ECA, along with temporal analysis, comparing RFO combustion impacts pre and post ECA enforcement at sites largely impacted by air from inside an ECA. Source apportionment was performed using Positive Matrix Factorization (PMF) on chemically speciated PM2.5 data from 2009 to 2018. Results for 7 coastal U.S. IMPROVE sites influenced by marine air masses within the NA-ECA showed an annual mean reduction of PM2.5 from RFO combustion of 79.0% (range, 60.2% to 91.5%) when comparing impacts from the pre-ECA (RFO average 2.7% S) period of 2009-2011 to the ECA 0.1% fuel S period of 2015-2018. In contrast, the Virgin Islands, Big Bend, and Baengnyeong Island South Korea IMPROVE sites were impacted by RFO combustion and were largely or wholly influenced by air masses from outside of an emissions control area. These sites saw a statistically significant 14.0% increase, a 21.0% decrease, or no statistically significant change, respectively, when comparing time periods pre and post ECA enforcement.Implications: This study performs source apportionment on PM2.5 monitoring data to identify 10 sites impacted by residual fuel oil combustion, mainly from marine vessel fuel use. The paper then evaluates the effects of enforcement of marine vessel fuel sulfur emissions control areas at reducing ambient impacts of this source on PM2.5. This study uses both temporal analysis of the source apportionment results, comparing source impacts before and after enforcement of marine vessel fuel sulfur emissions control areas, and spatial analysis, comparing source impacts between sites largely impacted or not impacted by airmasses originating inside of marine vessel fuel sulfur emissions control areas.

The purpose of this paper is to design a route and speed optimization method to simultaneously reduce sailing cost and time, considering Emission Control Areas (ECAs) regulations and weather condit...

In addition to sulphur oxides control, the North and the Baltic Seas have recently been designated as nitrogen oxides control area. Amidst ongoing developments in energy markets and international trade, shipowners have to develop cost-efficient strategies to comply with the new regulation. This study creates and tests a model calculating the incremental costs of abating NOx and SOx emissions under MARPOL Annex VI regulations for the following methods: SCR, HAM and internal engine modifications, marine gas oil, wet scrubbers, and liquefied natural gas propulsion. The model is tested empirically on a broad sample of 244 ships from the Swedish Commercial Fleet database for different operating contexts and fuel prices. Individual ship emission reductions and incremental abatement costs are calculated and the results are presented for the entire studied sample and per ship type class.The study also explores the sensitivity of the chosen abatement methods to cost determinants and to main engine time ope...

This article describes the load frequency control of a multi-area system. Each control area contains both a hydro and thermal power plant to form a multi-source multi-area hydro thermal system. The secondary proportional-integral controller has been tuned using Ziegler–Nichols, genetic algorithm, and fuzzy gain scheduling methods. On comparing the controller performance based on various performance indices, it is found that a fuzzy gain scheduling tuned proportional-integral controller is suitable for a multi-source multi-area hydro thermal system. Further improvement on the load frequency dynamics has been achieved by connecting superconducting magnetic energy storage unit in each control area and a static synchronous series compensator unit on a tie-line.

Development of effective management strategies for fire-prone landscapes is becoming increasingly important within South-East Australia. Monitoring of post-fire vegetation recovery is a critical process in developing these strategies, and is most effectively achieved using remote sensing techniques. This study analyses the effectiveness of Landsat 5 TM imagery and the Normalized Difference Vegetation Index (NDVI) in assessing regeneration rates of a mixed-species eucalypt forest in North-East Victoria, burnt on 6 December 2006. Multi-temporal analysis of regrowth data was performed, and standardised against an unburnt control area to eliminate any phenological factors affecting the region throughout the relevant timeframe. Results were compared with topoclimatic factors to reveal the level of stress affecting the study area both before the fire, and during post-fire regeneration.

Concentrations and spatial distribution of Zn, Cu, Cd, and Pb along two landscapes including a wastewater-irrigated area and a control area were determined to assess the impact of long-term wastewater irrigation and landscape properties on heavy metal contamination. Some disturbed and undisturbed soil samples were taken from soil trenches and soil cores, located on three main landscape positions (upper slope, midslope, and lower slope) in northwestern Iran. The investigation showed that the mean concentration of the heavy metals followed the order Zn > Cu > Pb > Cd in the wastewater-irrigated soil and Pb > Zn > Cu > Cd in the control soils. On average, compared to similar positions in the control region, the wastewater-irrigated regions contained 3.0 (midslope) to 4.9 (lower slope), 2.7 (midslope) to 4.6 (lower slope), 3.3 (upper slope) to 4.1 (lower slope), and 1.7 (upper slope) to 2.6 (lower slope) times higher amounts of Zn, Cu, Cd, and Pb, respectively. Significant positive relationships (P < 0.05) we...

Due to the existence of a threshold pressure gradient (TPG) in ultra-low-permeability reservoirs, the peripheral reserves of the wellbore are difficult to deploy effectively. The main problem is that it is hard to ensure that well pattern, well spacing, and drawdown pressure easily and accurately because of the existence of low-velocity non-Darcy flow in such reservoirs. Simple and accurate calculation methods of the problem are most popular with reservoir engineers, so effective deployment calculation methods of ultra-low-permeability reservoirs are presented in this article. They include control radius calculation, control distance calculation, control area calculation, and control coefficient calculation, which can be directly used in the evaluation of well pattern thickening of developed oilfields and reserves of undeveloped oilfields. Based on theory of fluid mechanics in porous medium considering TPG, the non-Darcy flow mathematic model was established to reveal the characteristics of press...

We model the effect of a road safety measure on a set of target sites with a control area for each site, and we suppose that the accident data recorded at each site are classified in different mutually exclusive types. We adopt the before–after technique and we assume that at any one target site the total number of accidents recorded is multinomially distibuted between the periods and types of accidents. In this article, we propose a minorization–majorization (MM) algorithm for obtaining the constrained maximum likelihood estimates of the parameter vector. We compare it with a gradient projection–expectation maximization (GP-EM) algorithm, based on gradient projections. The performance of the algorithms is examined through a simulation study of road safety data.

Hebron City has been subjected to complicated geopolitical conditions. Hebron′s urban growth has been highly influenced by various geopolitical factors imposed by the colonization power since 1967 and have been intensifying after 1994 Peace Process. The purpose of this paper is to study the association between the geopolitical factors and the urban growth patterns on the fringe area of Hebron City after 1996 Oslo Accords by examining the influence of the colonization settling activities, control area authority, and closure measures adopted by the colonization authorities since 2000. By comparing the urban growth densities based on maps between 1996 and 2007 and their patterns with the geopolitical map in the last ten years, the research found the following: First, there is a strong association between the restriction levels resulted from the geopolitical condition and the growth densities on the fringe area. Second, part of the proposed new jurisdiction area has limited expansion capacity as well as negative impacts on greenery areas.

This study deals with control of pest population in agricultural ecosystem using sterile insect technique (SIT). A three-dimensional stage-structured model of the pest under the release of sterile male has been considered. This article also considers the effect of this technique under immigration of wild insects in the control area. Moreover, the deterministic model is extended to a stochastic one allowing random fluctuations around the positive interior equilibrium. The stochastic stability properties of the model are investigated, both analytically and numerically. The thresholds of sterile males that obtained from our study might be helpful to understand and implement the technique properly.

A study of Echinococcus granulosus infection in dogs, with risk-factor analysis, was carried out in the endemic area of northern Turkana district, Kenya, using necropsy on 42 strays and a coproantigen-ELISA survey of 161 owned animals. During the post-mortem examinations, 14 (33%) of the necropsied dogs were found infected with E. granulosus, with a mean burden of 540 worms (range=two to 4080 worms). The 26 necropsied dogs that came from the north-western Lokichoggio division--an area where, from 1983 to 1997, there had been a continuous programme of hydatid control--showed a similar prevalence of infection to the other dogs (34.6%) but a significantly lower mean burden, of 53 worms (range=two to 300). Forty-two (26%) of the animals tested for Echinococcus coproantigen were found positive. Although the dogs from the Lokichoggio division were more likely to be coproantigen-positive (29%) than those from the central Kakuma division (20%) or the north-eastern division (18%), the differences were not statistically significant. In questionnaire-based interviews, the owners of the dogs tested for coproantigens were asked about possible risk factors for canine infection with E. granulosus. Women were found to have twice the level of contact with dogs as men. The results of a univariate analysis of the dog-owners' responses revealed six factors that appeared to be significantly associated with a coproantigen-positive dog: non-restraint of the dog (P0.001); dog fed on raw offal (P0.001); the improper disposal of slaughter offal (P0.001); the dog-owner's lack of knowledge about the transmission of echinococcosis (P=0.001); the dog not receiving anthelmintic treatment (P=0.003); and dog ageor =5 years (P=0.01). The results of a multivariate analysis confirmed that lack of dog restraint, access to raw offal, and young age of the dog (or =5 years) each significantly increased the risk of coproantigen positivity (P, 0.005). Dogs that scavenged from cooking pots, were used to clean babies, had access to the inside of houses, and/or slept indoors appeared, however, to be at no increased risk of coproantigen positivity. The present results are discussed in relation both to older information on the epidemiology and role of human behaviour in the transmission of E. granulosus in Turkana, and the effects of the hydatid-control programme that ran continuously in the north-western division of Turkana between 1983 and 1997.

There is currently a great deal of interest in documenting habitat use of birds in the boreal forest, especially in response to disturbances such as harvesting and forest fires. Studies have shown that some avian species are much more common in recently burned areas, whereas others are absent. Despite this, we know little about the immediate effect of a large forest fire, and its considerable alteration of habitat, on birds during a single breeding season. In 1995, a 72,000-ha forest fire in our study area gave us the opportunity to assess the effects of fire on reproduction of American kestrels (Falco sparverius) in comparison to an adjacent control area. In addition, we also examined territory occupancy by kestrels in the burned and control areas 8 y following the fire. We found no immediate effect of the fire on body condition of adult kestrels, their ability to hatch eggs, or to fledge at least one young. Birds breeding in the area that burned, however, did fledge fewer offspring per nest, and these nestlings had reduced body mass compared to control nests, possibly because of an immediate reduction in available prey following the fire. Nonetheless, given the profound alteration of habitat following the fire, the fact than any birds remained to continue breeding is remarkable. Territory occupancy of the burned area in 2003 was similar to 1995, the year of the fire, but occupancy in the adjacent control area declined during this period. It therefore appears that the control area is becoming a less suitable habitat for kestrels as the forest continues to mature, whereas the burned area is still providing viable habitat for kestrels. We present evidence suggesting that some of the differences in occupancy between the control and burned area may be due to fewer nest predators in the burned area in 2003.

The effect of remediation activities in formerly high-loaded industrial areas is measured conventionally in terms of decreased toxic loads. It is more difficult to investigate the effect on physiological parameters of the people living there. A non-invasive 15N-based organ function test, the [15N]methacetin urine test, was adapted to environmental-medical purposes for the detection of small deviations from the norm-range hepatic detoxification capacity. Parallel to the measurement of region-specific external exposure (especially by tri- and tetrachloro ethylene) and of the corresponding internal load (urinary trichloro acetic acid), the hepatic mono oxygenation capacity was determined. The study cohort consisted of 35 kindergarten children who were 3.3+/-0.5 years old at the beginning of the study. They lived in a high-polluted industrial village (n = 23) and in a non-polluted control village close by (n = 12), respectively. Children living in the polluted area were exposed a 2.3 times higher load and showed detoxification capacities 6% lower than the children in the control area. Improvement of the environmental situation led to exposure data decreasing by 70%, which is also reflected in smaller internal load and improved liver detoxification of the children in the polluted area. Then, between loaded and control area the mean hepatic detoxification was no longer significantly different (0.6%). The study shows that chronic low-dose exposure can disturb a hepatic function and that thereafter the capacity is recovered quickly in children. The stable isotope-based test is suited to characterize a health effect of multicomponent exposure by bioeffect monitoring within the framework of screening and testing the remediation efficiency.

Most analyses of health risks incident to the adoption of a product, process or facility treat only the effects of human exposure to pollutants. A growing body of research in the social sciences suggests strong linkages between health status and the economic status of populations. This paper considers the possibility that the effects of development on income distribution and employment may influence health as much as the resultant chemical exposures. The evidence presented in support of the socioeconomic linkage indicates adverse effects of transient economic growth and ultimately favorable effects of permanent expansions. A simple case study uses the development of coal mining in northern Wyoming to compare the effects of economic change with those of air pollution on local age adjusted mortality rates. The study area embraces counties with intensive mining activity, and the control area includes neighboring counties having similar terrain and climate, but with negligible mineral industry. This first ord...

Home treatment for acute mental illness is known to have advantages for some service users over hospital-based approaches. Generalisation from short term research studies to sustainable services in ordinary settings has been difficult. A service level and individual matched pairs ( n =58 x 2) study in North Birmingham indicated that home treatment can be developed with neutral cost-consequences. During the 6-week and 6-month follow-up periods users from the implementation team area had higher use of community-based care and lower use of hospital-based care compared to matched users from the control area. The combination of adding a home treatment team and halving the number of inpatient beds was, when compared to a control area, associated with (a) additional numbers of people receiving acute care (b) a lower cost per individual and (c) no difference in overall service cost.

The problem of simultaneous tuning of the automatic generation control (AGC) regulator’s gains of multi-area interconnected power system is carried out in this manuscript. Based on the types of area interconnections, a power system model consisting of reheat turbines is investigated by two test cases for the AGC study. In one of the test case AC link is used as area interconnection, whereas the parallel combination of AC/DC links is used as area interconnection in other test case. Each test case control area is consisting of plants with reheat thermal turbines. Genetic algorithm (GA) is used to globally optimize the gains of proportional integral-based AGC regulators with simultaneous optimization of frequency bias coefficient and tie-line power flows. The dynamic response curves are obtained for various system states with the implementation of designed GA-based AGC regulators considering 1% load perturbation in one of the areas. The conventional AGC regulators are also developed using the popularly known Ziegler–Nichols technique. The investigations carried out demonstrate the superiority of proposed regulators over the conventional AGC regulators. The incorporation of DC link in parallel with AC link as an area interconnection has also exhibited favorable effect on dynamic response of the system.

In a Picea mariana forest near Fort Norman, NWT, Canada, a corridor was cleared in the spring of 1985 to simulate a seismic line or pipeline disturbance. Salix arbusculoides, the dominant erect shrub, was monitored for three growing seasons after canopy harvesting. Leaf area was not consistent between the three years in either the cleared right-of-way or the undisturbed forest control area. Relative to control shrubs, leaves were significantly larger in right-of-way shrubs in 1985, virtually identical in size in 1986, and smaller in the right-of-way shrubs in 1987. In 1986, stem production was so great for right-of-way shrubs that the mean leaf/stem biomass ratio for this sample was smaller than both the other two years for right-of-way samples and the control sample for that year. Right-of-way shrubs were consistently shorter in height than control shrubs; by the third growing season, however, this difference was negligible. Right-of-way shrub canopy volume was significantly less than control shrubs only...

This paper addresses the design of decentralized controllers for interconnected large-scale electric power systems. The system is modelled as a collection of independent subsystems or control areas interconnected through high voltage tie-lines. For each control area an independent model is derived using the information contained in the interface variables. Conditions are given for the existence of these local models. Decentralized controllers are designed to solve the “Load Frequency Control” problem. The proposed decentralized control method is not limited to power systems. It is applicable to any interconnected large-scale dynamical system.

In this study, differences in feelings of insecurity and ways of coping were assessed between residents of a chemical complex and a control group at a distance of at least 15 km from that complex. The results show that the residents of the industrial area judge the hazards as less threatening and less unacceptable than the control group and report less feelings of insecurity. The residents are less likely to read newspaper articles concerning environmental or industrial hazards and judge these newspaper accounts to be less credible than the control group. No differences were found between the residents of the chemical complex and the control group with regard to another hazard, living in the vicinity of a storage facility for radioactive waste. Our results are mainly explained by social learning theory in which it is assumed that, by a process of verification, the residents of the chemical complex are less affected by the alarming content of mass media reporting and are less negatively biased than people in the control area

The rates of fetal loss and family planning acceptance among Bhopal gas victims from 1984 to 1989 were compared to those of a control group. In all, 136 eligible women in the affected area and 139 women in the control area were interviewed. Care was taken to ensure that these women had conceived at least once during the previous five years. The The fetal loss rate among the gas-affected women was abnormally high (26.3 per cent) compared to that of women in the control area (7.8 per cent). Family planning acceptance in both areas was similar, with most women using permanent methods. In the case of temporary methods, the percentage of use was higher in the gas-affected area.Rates of fetal loss and family planning acceptance of severely-affected Bhopal gas victims are compared to those of an unaffected control group over the period 1984-89. 136 women were interviewed from the former area, while 139 were selected from the latter. Eligible women conceived at least once over the previous 5 years, and were aged 20-44 years. Communities of similar socioeconomic status were selected, and equal proportions of Hindus and Muslims interviewed in both. Defined as loss up to 28 weeks of gestation, fetal loss among the gas-affected women was 26.3%, compared to the .78% loss among women in the control group. Acceptance of family planning was similar to both areas, with most women opting for permanent methods. Laparoscopy was the most widely accepted of these methods in both areas. For temporary methods, higher acceptance was evidenced in the gas-affected area. The condom was the most widely known and accepted such method, followed by oral contraceptives and the IUD. The number of living sons significantly affected the current use of contraceptives. While acceptors of temporary method are on the rise in the affected area, greater emphasis needs to be given to advocating spacing methods over more permanent family planning options. Additionally, the abnormally high level of fetal loss in the gas-affected area points to the persistent effects of methyl isocyanate released in the 1984 Union Carbide plant disaster. Oddly enough, however, child survival has increased in the affected area as a result of frequent medical personnel visits since the disaster.

In many arid and semi-arid countries, wastewater irrigation is becoming a common practice in agriculture. In this study, the effect of long-term (40 years) wastewater irrigation on selected physical and hydraulic properties of soil in different parts of a landscape was investigated. The performance of some infiltration models, including Philip (Ph), Kostiakov (Kos), Kostiakov-Lewis (Kos-L), Horton (Ho), Huggins and Monke (Hug-M), and linear and nonlinear Smith-Parlange (S-P(L) and S-P(NL)), was compared. This study was performed in the Urmia region, Iran, where flooding wastewater irrigation has been practised for at least 40 years. Five paired sites, each of which contained a measurement location at the wastewater-irrigated (WWI) and adjacent control area were studied. Accuracy of the infiltration models was evaluated using several statistical criteria, including root mean square error (RMSE) and Akaike information criterion (AIC). The models were classified into groups using cluster analysis bas...

The effects of human pedestrian pressure on an exposed rocky shore lying within a newly‐declared marine reserve near Cape Town, South Africa, were investigated. Transects were marked across the intertidal zone of a little‐frequented section of the shore and subjected to trampling up to 500 times per month. Immediate effects of pedestrian impact included the dislodgement of dead barnacles, damage to algae and the crushing of small numbers of amphipods and isopods. Long‐term effects could, however, not be found, and those transects subject to the most intensive pressure did not differ significantly from a control area. A survey of types of footwear used by people walking in the intertidal indicated that over 85 percent used no footwear at all. This lack of protection forces the majority of pedestrians to proceed with caution in order to avoid injury, and sumultaneously minimises the damage they inflict on intertidal biota. It thus appears likely that wave action is of considerably greater importance to inte...

We study, in the vicinity of Los Angeles International Airport, the effect of jet noise on mental hospital admissions. The maximum noise area (where the maximum fly-over noise exceeds 90 dBA) shows a 29% increase in admissions over those of a corresponding control area, as like the target area as possible, except that in the control area jet noise is not a dominant factor. The results are similar to those of a previous study carried out near Heathrow Airport.

The accuracy of an isopleth map depends upon the soundness of the procedure by which the map is constructed. The steps presented here include preparation of a dot map on which a circular area of constant size, drawn on a transparent medium, is centered over each control point and the dots within it are counted in order to assign a value to that point. Such a procedure insures that control areas are consistent in size and it allows the mapmaker to choose the arrangement and number of control points. It also results in a total volume that accurately reflects the total number of objects. The size of the circular control area will affect the smoothness of the resulting isopleth map.