February 22nd, 2010 by
This paper looks at how the Oracle Accelerate program helps to reduce the time, complexity and cost of deploying Oracle solutions in order to make them suitable for mid-market companies which often lack the IT expertise and resources of their larger counterparts. Request Free!
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Oracle Accelerate Not Just Smart But Timely
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February 12th, 2010 by engineering magazines
In a conventional marine diesel engine the power is produced by hot compressed air igniting fuel sprayed under very high pressure into the cylinder head. A marine diesel engine does not use a carburetor to mix fuel and air or spark plugs to ignite the mixture. Instead it employs the pistons to compress the air to 3000 kPa which causes it to become extremely hot and the fuel is ignited as soon as it is injected into the cylinder.
Some marine diesel engines are fitted with a heater plug in the inlet manifold or a glow plug in the pre-combustion chamber of each cylinder to provide additional heat to the combustion air during starting.
Diesel engines are heavier and slower revving than petrol engines but they are also more reliable because they do not rely on external carburetion or an electrical spark for ignition.
Newer engines use an electronic fuel injection system whereby fuel and air are mixed more thoroughly in the pre-combustion chamber before entering the cylinder. This system maximizes power and fuel economy and is also less polluting.
Every boater should have an understanding of how their engine works so let’s start by explaining the mechanical cycles.
Most reciprocating piston internal combustion engines work on one of two mechanical cycles-either the four-stroke cycle or the two-stroke cycle. These cycles designate, in correct sequence, the mechanical actions by which the fuel and air gain access to the engine cylinder, the gas pressure – due to combustion – is converted to power and, finally, the burnt gas is expelled from the engine cylinder.
The Basic Four-Stroke Diesel Engine
From its name, it is obvious there are four strokes in one complete engine cycle. A stroke is the movement of the piston through the full length of the cylinder and – since one such movement causes the crankshaft to rotate half a turn – it follows that there are two crankshaft revolutions in one complete engine cycle.
The four strokes in the order they occur are:
1. Inlet stroke. With the inlet valve open and the exhaust valve closed, the piston moves from top dead center (TDC) to bottom dead center (BDC), creating a low-pressure area in the cylinder. Clean, filtered air rushes through the open inlet valve to relieve this low-pressure area, and the cylinder fills with air.
2. Compression stroke. With both valves closed, the piston moves from BDC to TDC, compressing the air. During this stroke the air becomes heated to a temperature sufficiently high to ignite the fuel.
3. Power stroke. At approximately TDC, the fuel is injected, or sprayed, into the hot, compressed air, where it ignites, burns and expands. Both valves remain closed, and the pressure acts on the piston crown, forcing it down the cylinder from TDC to BDC.
4. Exhaust stroke. At approximately BDC the exhaust valve opens and the piston starts to move from BDC to TDC, driving the burnt gas out of the cylinder through the open exhaust valve.
The Two-Stroke Diesel Engine
The two-stroke engine uses two piston strokes to complete one power stroke and, therefore, fire twice as often as a four-stroke engine. A two-stroke engine is smaller and simpler with fewer moving parts. A two-stroke engine has the potential to produce twice as much power as a four-stroke engine of the same size, however, because of the extra fitting required in a two-stroke diesel engine, for example blowers and governors, they become more expensive to produce. There has been a shift towards four stroke diesel engines which have become more efficient and smaller.
Protect Your Marine Diesel Engine
Protect your engine by avoiding long periods (more than 10 minutes) of idling in a “no-load” situation. This is often done to charge batteries or cool refrigeration but if done repeatedly it will glaze the bores of the engine and cause premature engine failure. If the vessel is in a berth the engine can be put in gear to create load at idle.
All boat owners should have an understanding of basic marine diesel engine maintenance to keep themselves and their families safe on the water.
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February 6th, 2010 by
As an IT Professional who is migrating between SharePoint servers, upgrading from SharePoint 2003 to 2007, planning for migration to SharePoint 2010, or re-organizing your SharePoint content, SharePoint Site Migration Manager is an easy-to-use and convenient way of moving your SharePoint data. With its familiar copy-and-paste-style user interface, you can quickly migrate all SharePoint sites, libraries, lists, web parts and permissions between servers. Request Free!
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SharePoint Site Migration Management Software FREE 15-Day Trial
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January 24th, 2010 by engineering magazines
This article will help you to know more about Gas and Diesel. The plus and minus or strengths and weakness of both fuel either gasoline or diesel. This article will discussed both fuel from various aspects such as price, impact on the machine, maintenance etc.
Cost
Due to the high compression ratios and resulting high cylinder pressure in diesel engines, they must be built to withstand a lot more punishment than gas engines. The parts that are spruced up include a thicker block and cylinder heads, pistons, crankshaft, and valves, which can be very costly indeed.
When it comes to the price, gas wins this one by far. Diesel costs a lot more to own than gas, which is one of the main reasons why people tend to choose gas over diesel.
Fuel cost
Diesel fuel is easier to refine, taking less time to get from raw petroleum to final product from gas, giving it a lower price than that of gas. On the other hand, within the United States, diesel is priced the same or just a bit below regular unleaded gas.
“As we head to war with Iraq, President Bush wants to make one thing clear: This war is not about oil, it’s about gasoline.” 
Noise and vibration
Despite many improvements in noise isolation and engine noise technology in trucks over the last 10 years, diesels are still much louder and shake more than gasoline powered vehicles. At idle, the clatter and shake of diesel vehicles are clearly noticeable, while it can be hard to tell if the gas engine is even running.
Cold weather
If you’ve tried to start a diesel engine on a cold day, you know that gas is by far easier to start. Diesels don’t have spark plugs like gas engines do, as the fuel is ignited once it’s injected into the cylinder that is already under pressure. When it gets cold, the air isn’t hot enough to ignite the diesel fuel.
Maintenance
Maintenance on a diesel vehicle is more expensive, thanks to many things including the larger volume of oil in the engine and the fact that fuel filters and water separators must be serviced more often than gas vehicles. Gasoline engines have a bigger advantage due to extended service periods on spark plugs, engine oil, and even antifreeze.
Making that final choice between gas and diesel comes down to what you’ll do with your vehicle and where you live. If you use your vehicle for quick, fast acceleration and rarely ever haul heavy loads, and don’t plan to keep your vehicle past 100,000 miles, you may want to consider buying a gasoline vehicle.
Gas runs smoother, fuel is easier to find, and they are easier to start in cold weather. On the other hand, if you plan to tow, value good fuel economy and plan on racking up a lot of miles, then you’ll want to buy a diesel.
Price is also an important consideration, as diesel vehicles can be a bit more expensive than gas. If you aren’t worried about price, then diesel may be your best bet. For trucks, diesel is by far the superior choice for those who like to haul heavy loads on a frequent basis.
As the last words, I like this quote so much:
“What is needed is an all-out science project to get vehicles off of gasoline, rather than off of the earth.”
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January 18th, 2010 by
Receive this FREE “Electronic Medical Records” Buyer’s Guide along with complimentary, no obligation price quotes (via phone and email) from multiple quality & independent Electronic Medical Records Systems providers. There are hundreds of EMR systems available today, targeted at every type and size of practice. This Electronic Medical Records Systems Buyer’s Guide will help you ask the right questions to evaluate both the software and the vendor so you can choose the best solution for your practice. Request Free!
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Replace all your paper patient charts and medical records with Electronic Medical Records System
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January 14th, 2010 by
According to the U.S. Environmental Protection Agency (EPA), the energy consumption of data centers has doubled in the past five years and is expected to nearly double again in the next five. If left unchecked, data centers, PCs, computing and telecommunications networks could be among the biggest greenhouse gas emitters by 2020, according to a new report by McKinsey & Company. Global leaders, IBM® and Cisco, are working together to prevent this from happening by helping organizations reduce their environmental impact. The two companies envision a world where everything is instrumented, interconnected, and intelligent. Interested? Read this paper to learn the big plans both companies have for an energy-efficient future. Written by: Cisco and IBM® Request Free!
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A Greener Planet Starts with Smarter IT
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