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| An ash tree growing on a trail beside the Poulaphouca Reservoir. © Eugene Brennan |
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| Water level in Golden Falls Lake, Ballymore Eustace. Image courtesy ESB hydrometrics |
The Golden Falls lake rose 1.44 m since yesterday. That's a bit of a jump since the downwards trend over the last week or so, and equivalent to approximately 370,000 cubic metres (m³) of water. The Golden Falls lake doesn't really provide a large storage capacity compared to the much larger Poulaphouca Reservoir, which has a surface area of approximately 22.6 square kilometres (km²), 86 times that of the Golden Falls lake. According to Esbarchives.ie, the head of the Golden Falls dam is 17.4 m. If the walls of the 256,000 m² lake were vertical, that would give a storage capacity of about 4.4 million m³ of water. To put that into perspective, if it were empty, it could store only about a day and a quarter's worth of the water that passed through Kilcullen at peak discharge last week. So dropping the level isn't a huge advantage as regards overall storage and I guess the objective is to try and make more "headroom" available in the Poulaphouca Reservoir to cater for extended periods of heavy rain.
Image courtesy ESB hydrometrics.
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| Movie projector from Kilcullen Town Hall Cinema. © Eugene Brennan |
I was examining the nameplate (rating plate) of Kilcullen Town Hall's former film projector the other day, now located in a corner of the porch of the heritage centre. The Peerless Magnarc carbon-arc lamphouse, paired-with the projector and manufactured by the J. E. McAuley Manufacturing Company of Chicago, Illinois, ran on DC electricity. A rectifier may have been built into the projector to convert mains AC to DC, or possibly it was a separate piece of equipment.
Arc lamps were used as an intense white light source for projectors, essential for producing a bright image on the screen. They were also used of course in search lights during WWII, for spotting enemy aircraft. Arc lighting generates large amounts of harmful UV radiation and filters would presumably have been used in the optics to block this. Electric arcs also produce a lot of heat, as anyone who has ever done electric welding would know, and again, filtering would have been necessary to protect the film. Carbon rods were consumable items used in arc lamps, just like the rods used for arc welding and had to be replaced frequently. In the early days of movies, film stock was manufactured on a highly flammable nitrate base and fires were common. It's thought that a candle ignited a reel of nitrate film, resulting in the Drumcollogher tragedy of 1926, in which 46 people perished.
I'm not sure what the "motor" is, referred to in the spec. Since the lamp was an add-on unit to the projector, it was probably not the film feed motor, but rather a motor powering a cooling fan for the lamp or one that fed the electrodes as they were consumed.
The photo mounted on the projector shows actor Paul Newman standing in front of it on the occasion of his visit to Kilcullen over 20 years ago. At that stage, the projector was still located in the projection room.
In 2006, Brian Byrne published a more detailed article in the Kilcullen Diary which provided more information about the projector’s projection unit.
Arc volts 31 - 46
Arc amps 32 - 100
Motor volts 31 - 110
Motor amps 0.5 - 1.4
J.E. McAuley Mfg. Co.
Chicago, ILL
United States of America
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| Rating plate attached to the projector. © Eugene Brennan |
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| SLS rocket. Image credit: NASA |
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| Wastewater treatment plant. AI image by ChatGPT. |
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| OSI benchmarks. Image reproduced with permission from Dr. Catherine Porter, author of this RTÉ article. |
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| © Eugene Brennan |
If possible I always repair rather than replace. I've always done this before it became a trendy green thing, simply because it saves money and I've never had lots of money to spare. I remember my father fixing a hole in the silencer on the car, with a section of tin plate, cut from a Cow & Gate baby formula tin, and fixing it to the silencer with coat hanger wire. So I didn't lick it up off the ground, as the saying goes. I've got slagged off by Millennials and successive demographic cohorts, for doing such things, and asked why I don't "just but a new one". Anyway, today I was fixing the tail light for my bike.
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| Water level in Poulaphouca reservoir |
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| Higher-than-normal water levels under one of the arches of Kilcullen Bridge. © Eugene Brennan |
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| Poulaphouca Reservoir viewed from above Valleymount. © Eugene Brennan |
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| Water level stats courtesy ESB hydrometrics. |
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| Water level stats, courtesy ESB hydrometrics. |
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| Golden Falls lake. Image courtesy Google Maps, Airbus and Maxtar Techmologies |
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| © Eugene Brennan |
"Plastic" is a term applied to any material that can be moulded or bent into shape; for instance, soft toffee, modelling clay, or red-hot iron is plastic because it can be reshaped. In general though, when we speak of plastic, we mean polymers or synthetic materials made from petrochemicals.
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| AI image generated by ChatGPT |
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| Image courtesy the ESB |
Even with the large discharges from the golden Falls dam, the level in the lake has risen a metre in the last two days. This would be due to significant discharges from the Poulaphouca dam. I'm not sure what the max allowed level is for the lake. I'll see if I can find out. Both the Golden Falls and Poulaphouca lakes act as buffers to smooth out flow. In fact they're analogous to three types of systems, both mechanical and electrical: an air compressor tank, a flywheel on a machine such as an engine or punching machine and the filter capacitors in a DC power supply. In signal theory, all these systems act as low pass filters, storing energy and smoothing out "bumps", converting pulses into smooth ripples—ideally small ripples. If the ripples are too big in an electrical power supply, you get mains hum, which you may have heard in a bad PA system. Back to the lakes, they act as buffers. Once they fill, they no longer smooth out the bumps and the full flow of the River Liffey upstream of Poulaphouca feeds through the system.
Image courtesy ESB.
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| Crop of a Lawrence Collection photo of the River Liffey in Kilcullen. Image courtesy the National Library of Ireland. |
A close-up crop from a Lawrence Collection photo, circa 1900, showing a section of the river bank that had slipped into the river near what's now the entrance through the bushes onto the mass path. It's probably taken from the vantage point of the bridge or the slope where the Valley Park is now located. The slippage could have occurred decades or hundreds of years before. Interestingly, as far as I remember it, there was a ditch just before the fence in the photo (not sure whether it was the same fence in the 70s), which we used to have to step over to walk further along the path. I noticed recently, from hearing water running, that the ditch, if it's the same one, is now maybe 20 feet further into the bushes and in a culvert/pipes. So the bushes must have spread outwards over the last 50 years or so into the field.
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| Poulaphouca Lake. © Eugene Brennan |
Water isn't released directly into the River Liffey south of Ballymore Eustace from the Poulaphouca reservoir — it's discharged indirectly from the Poulaphouca dam into a compensatory lake in Ballymore. This acts as a buffer, protecting the river from huge surges and flooding. Although it's not related to surges on the river, a surge tank adjacent to the Liffey bridge over the gorge on the N81 protects the pipes, or penstocks, that deliver water to the turbines in the generating house from hydraulic shock.
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| Devil's Tower in Wyoming. Ben Stephenson from Cleveland, OH, CC BY 2.0 , via Wikimedia Commons |
If you were watching Close Encounters of the Third Kind this afternoon (I hadn't seen it for maybe 15 years), you would have seen the towering rock formation that's used as a plot device and features in the end of the movie when the huge spaceship appears and the aliens emerge. This is Devils Tower in Wyoming, classed as a butte and possibly a laccolithic formation, composed of igneous rock. A butte is an isolated hill with steep, often vertical sides and a flat top. Igneous rock began as molten rock or magma that originated from inside the Earth, and then cooled.
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| © Eugene Brennan |
Why is the sky blue? What is air made of? How many stars are there?
World
of wonder fun science facts that every child should know! This article
covers space, nature, technology, engineering, elementary mathematica,
chemistry, physics and biology.
Science is fascinating and tries to
explain how everything in the world and outer space works. Science gives
us the answers to questions like "What is electricity?" and "How does
an aeroplane fly?" Read on and learn 100 more cool science facts!
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| Fence on Church Mountain, Co. Wicklow. © Eugene Brennan |
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We all know that when an object is released from a certain height, it starts to fall. This, of course, is due to gravity, or more specifically the gravitational force of attraction between the object and the Earth. The force of gravity causes the object to accelerate and increase in velocity as it falls downwards towards the Earth. In actuality, both the Earth and the object are mutually attracted to each other, and the Earth moves upwards at the same time. However, since it's so massive in comparison to a small object and the force is so small, its movement is minuscule.
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In this tutorial, we'll first learn the absolute basics about triangles. Then we'll learn about trigonometry which is a branch of mathematics that covers the relationship between the sides and angles of triangles.
