Simulation of the response of a silicon pixel detector

A model to simulate the response of a silicon pixel detector is described. The effects of geometrical charge sharing, electronic noise threshold dispersion, capacitive coupling between pixel channels and d -rays production have been taken into account. The model has been tested on the Omega3chip, which is the direct predecessor of the ALICE pixel detector, to be used in the inner tracking system of the ALICE experiment. The model is able to reproduce the experimental data and the resulting parameters are consistent with the measurements made on the Omega3chip. Key words:silicon pixel, simulation PACS:07.05.T,29.40.

Davis Creek Dredge Channel Data Report

Introduction Davis Creek is located in Mathews County, Virginia (Figure 1) and empties into Mobjack Bay, a small bay in the lower Chesapeake Bay. The creek has a narrow mouth that splits into three prongs (Figure 2). The eastern prong is shortest at 2,200 ft from the mouth, and the western prong is the longest extending about 3,000 ft from the mouth. The Marina on Davis Creek occurs on this prong. Land use adjacent to the creek is mostly residential with some agriculture and wooded properties. The headwaters do not have extensive marsh. Instead the creek terminates soon after the channel narrows at the headwaters. Davis Creek has historically been the location of an active working waterfront. (...

Living Shoreline Sea-Level Resiliency: Performance and Adaptive Management of Existing Sites Year 3 Summary Report

The focus of this study was to research the resiliency of rock/sand/plant living shoreline protection systems. These systems have been used in Chesapeake Bay for 40 years to reduce erosion, protect infrastructure, and create habitat that is disappearing from the shoreline as sea level rises. The goal was to determine how they have been affected by storm surge and associated wind-driven waves, sea-level rise. This data informed adaptive management strategies to create site-specific morphologically-resilient projects. The objectives of this 3-year project is monitoring the effectiveness of nature-based resilience projects over time such as those that use hybrid living shoreline management strategies on medium to high wave energy shorelines. To create effective shore protection on these higher energy shorelines, structures are needed in addition to sand and plants to maintain ecosystems along the shoreline. In particular, rock sills and headland breakwaters are used in Chesapeake Bay to maintain continuous coastal profile and a more natural land-water interface

Aberdeen Creek Dredge Channel Data Report

Aberdeen Creek is located on the York River in Gloucester County, Virginia (Figure 1). At the narrow confluence of the York and Aberdeen, the creek takes about a 90-degree bend to the north (Figure 2) and widens to about 700 to 800 feet (ft) for about 2,000 ft. The creek then divides into two branches, one continuing north and one going east. These two prongs narrow quickly and become thin meandering tidal channels with adjacent marsh. The land use around the creek is mostly agricultural and wooded with some residential properties along its east side and along the York River shoreline. The west side of the creek is defined by a sand spit vegetated with high and low marsh that widens quickly into a peninsula north of the entrance. This spit has formed over the years of southward transport of eroding bank sediment along the York River. A sandy spit also occurs on the south side of the channel and has moved across a small tidal channel/marsh coming into Aberdeen Creek from the southeast. (...

Timberneck Creek Dredge Channel Data Report

Introduction Timberneck Creek is located in Gloucester County, Virginia (Figure 1). It is a long, but narrow creek that empties into the York River. The mouth is a wide embayment, but farther north, the creek narrows to about 400 ft wide and extends for about 2 miles to its marshy headwaters. The interior of the creek is irregular with many very small lateral creeks/marsh drainages emptying into the Timberneck. Timberneck Creek has never been dredged and a federally-defined channel does not exist at the site. As a new dredging project, the channel design must balance safety, economic, and sustainability requirements. The channel also must be wide and deep enough to safely accommodate vessel traffic but not so large as to require excessive dredging or habitat modification (Figure 2). (...

Hog Island Shore Protection and Habitat Restoration Living Shoreline Project

Hog Island is an emergent estuarine marsh complex that is part of the overall Guinea marshes (Figure 1). These marshes are located at the confluence of Mobjack Bay and the York River in Gloucester County, Virginia. Hog Island is a high wave energy eroding shoreline along its south-face on the York River, and lower wave energy along its west and east flanks that occur on Monday Creek (Figure 2). The marsh consists mainly of grasses such as Spartina alterniflora and Spartina patens. A higher, sandy area along the higher energy shorelines has some scrub shrub. Two small ponds and a small creek occur on the interior of the marsh. The edge of the island is irregularly shaped with exposed peat and peat scarps along the shoreline (Figure 3). Hog Island is critical for several reasons including: (1) Guinea Marsh Islands are important maritime habitats for shorebirds, waterfowl, as well as many important marine species; (2) Guinea Marsh Islands provide a storm surge break to the marsh complex inside Monday Creek and down the Mobjack Bay side towards the Severn, which will soon be marshes owned by the Virginia Department of Wildlife Resources; (3) Monday Creek has two aquaculture operations inside of the creek and the uplands provide a storm break for growing oysters; and (4) There are many FEMA repetitive loss structures in Guinea. Protecting these islands reduces the amount of storm surge energy entering the creek and thus reduces flood damage. As such, this project took conservation, resiliency, and protection aspects into consideration when assessing Hog Island for shore protection and habitat restoration. To determine management strategy suitability, the site assessment included hydrodynamic, physical, and biotic conditions existing at the site

Data Collection at Fifteen Selected Creeks in Support of Shallow Water Dredging on Virginia’s Middle Peninsula - Methods & Data Report

Federal funding has been historically available for the Army Corps of Engineers for shallow draft navigation projects. However, past and recent subsidies have not provided ample funding at levels to sustain maintenance dredging for the 17 federal navigation channels on the Middle Peninsula. Further, funding for maintenance of non-federal channels has been historically neglected by the Commonwealth of Virginia until the Virginia General Assembly established the Virginia Waterway Maintenance Fund in 2018. For the past decade the Middle Peninsula Chesapeake Bay Public Access Authority, the Middle Peninsula Planning District Commission and its member jurisdictions, and the Virginia Institute of Marine Science Shoreline Studies Program have worked to advance local solutions and alternatives to address dredging needs in the Commonwealth