what is course overlay

A course overlay is an image with transparency spread over the entire plot of the course. Typically this is a

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What is the course overlay tool used for?

About this tool: The course overlay tool should only be used for guidance. It allows you to check that the lectures for your chosen optional courses can timetable with the lectures for your mandatory courses.

Can a student choose a course combination from a course overlay?

About this tool: The course overlay tool should only be used for guidance. It allows you to check that the lectures for your chosen optional courses can timetable with the lectures for your mandatory courses. It does not provide a definitive answer on whether a student can choose a given course combination.

What are the different types of overlay strategies?

Overlay strategies may be passive (merely seeking to hedge risk) or active (looking to generate additional investment returns). Many different types of investors – from individuals to institutional investors – hold stocks, bonds, or other investments that are denominated in foreign currencies.

How does the overlay manager execute the plan?

The overlay manager typically executes the plan using one or more currency forward contracts that lock in the relevant currency exchange rate at a specified level.

What is pavement overlay?

Generally, pavement overlays are used to restore surface course (both HMA and PCC) characteristics (such as smoothness, friction and aesthetics) or add structural support to an existing pavement. However, even a structural overlay needs to be placed on a structurally sound base.

Why do you need a tack coat before overlaying?

Before overlaying, a tack coat should be placed on an existing pavement to ensure adequate bonding of the overlay to the existing pavement surface. Proper tack coat application can be critical to long-term pavement performance.

What is a prelevel paver?

Leveling courses (or prelevel) are initial lifts placed directly on to the existing pavement to fill low spots in the pavement (Figure 2). Typically, pavers use an automatic screed control, which keeps the screed tow point constant regardless of the tractor unit vertical position. This allows the paver to drive over a rough, uneven pavement yet place a relatively smooth lift with extra HMA making up for low spots in the existing pavement.

Is milling a good alternative to leveling?

For many situations, milling may be a superior alternative to a leveling course. Leveling course quantities are difficult to accurately estimate and leveling course thicknesses are usually small, precluding the use of nuclear gauge density testing. Thus, adequate mix density is difficult to achieve and measure. In some overlay projects a combination of milling and leveling course application may be best.

Can HMA overlay be placed on PCC?

Placing a HMA overlay on a jointed or cracked PCC pavement involves some special considerations in addition to the usual repair and leveling. Jointed plain concrete pavement (JPCP) is placed in discrete slabs and both JPCP and continuously reinforced concrete pavement (CRCP) tend to crack into discrete sections.These slabs/sections tend to move as individual units. Although HMA overlays can accommodate small differential subgrade movement without cracking, the large differential movement at slab and crack interfaces is great enough to crack a HMA overlay (called reflection cracking ). There are several techniques to prevent (or at least delay the onset of) reflection cracking:

What is an active overlay strategy?

In contrast to passive currency overlay strategies, an investor may opt for an active overlay strategy. Active overlay strategies still aim to hedge exchange rate risk for an investor; however, it leaves part of the investor’s portfolio unhedged.

What is currency overlay?

Currency overlays can be an important risk hedging tool for investors who hold significant amounts of foreign stocks or other investments that can be impacted by fluctuating currency exchange rates. Overlay strategies may be passive (merely seeking to hedge risk) or active (looking to generate additional investment returns).

What is the difference between the lower and top layers of asphalt?

As you may or may not know, an asphalt pavement section or structure is made up of multiple and different asphalt layers (lifts or courses). The lower layers are constructed for strength and support, while the top layer is constructed for smoothness and longevity. The layer or course that is often overlooked is the leveling course (middle).

What is the benefit of leveling a pavement?

The final benefit of the leveling course involves longevity of the pavement. The additional layer of asphalt helps to reduce and prevent reflective cracking from the existing pavement that was overlaid. Because of the leveling course, there is additional pavement for the crack to work through and also a separation in the lifts ...

Can I install a leveling course over existing pavement?

The leveling course can be installed over new pavement, existing pavement, or milled pavement. When installing the leveling course, it is important to follow best paving practices ensuring the pavement is clean, dry, and a tack coat has been properly applied. The thickness of a leveling course will vary across the paving mat.