In the 1850s British railway companies started introducing a single standard time to make their timetables consistent. Before that, every city would set its own clock based on the observation of the position of the sun. Nowadays, precise time standards are not only needed so people don’t miss their trains but also make modern communication technologies and satellite navigation work.
Generally, there are two methods of defining time, one is based on the local passage of time as measured by atomic clocks, while the other relies on the exact measurement of Earth’s rotation. The latter is not an easy exercise that involves extragalactic radio sources or huge laser-based gyroscopes. The constant survey of the Earth’s spin tells us that days are constantly getting longer, but surprisingly, severe earthquakes and weather phenomena can also take little discrete bites out of the planet’s supply of rotational kinetic energy.
How do we keep our ultra precisely measured time, the rotation of the Earth, and our position in the heavens in line?
It’s really beginning to feel as though the problem of climate change is a huge boulder rolling down a steep hill, and we have the Sisyphean task of trying to reverse it. While we definitely need to switch as much of the planet over to clean, green energy as soon as possible, the deployment should be strategic. You know, solar panels in sunny places, and wind turbines in windy places. And for the most part, we’re already doing that.
A test unit in Okinawa, Japan. Image via Challenergy
In the meantime, there are also natural disasters to deal with, some of which are worsened by climate change. Eastern and Southeast Asian countries are frequently under the threat of typhoons that bring strong, turbulent winds with them. Once the storms pass, they leave large swaths of lengthy power outages in their wake.
Studies have shown that these storms are gaining strength over the years, leading to more frequent disruption of existing power systems in those areas. Wind power is the ideal solution where storms have come through and knocked out traditional power delivery all over a region. As long as the turbines themselves can stand up to the challenge, they can be used to power micro-grids when other delivery is knocked out.
Bring On the Typhoons?
Unfortunately, the conventional three-bladed wind turbines you see dotting the plains can’t stand up to the awesome power of typhoons. But vertical axis wind turbines can. Though they have been around for many years, they may have finally found their niche.
The US Nuclear Regulatory Commission (NRC) recently announced that it had approved certification of NuScale’s SMR (small modular reactor) design, completing its Phase 6 review of NuScale’s Design Certification Application (DCA). What this means is that SMRs using NuScale’s reactor design can legally be constructed within the US as soon as the rulemaking process completes. An NRC certification would also mean that certification of the design in other countries should pose no significant hurdles.
A question that remains unanswered at this point for most is how this certification process at the NRC actually works. Are there departments full of engineers at the NRC who have been twiddling their thumbs for the past decades while the US nuclear industry has been languishing? What was in the literally millions of documents that NuScale had to send to the NRC as part of the certification process, and what exactly are these six phases?
Stay tuned for a crash course in nuclear reactor certification, after a bit of SMR history.
When it comes to measuring time on microcontrollers, there’s plenty of ways to go about things. For most quick and dirty purposes, such as debounce delays or other wait states, merely counting away a few cycles of the main clock will serve the purpose. Accurate to the tens of milliseconds, they get the average utility jobs done without too much fuss.
However, many projects are far more exacting in their requirements. When you’re building a clock, or a datalogger, or anything that relies on a stable sense of passing time for more than a few minutes, you’ll want a Real Time Clock. So called due to their nature of dealing with real time, as we humans tend to conceive it, these devices take it upon themselves to provide timekeeping services with a high degree of accuracy. We’ve compiled a guide to common parts and their potential applications so you can get things right the first time, every time.
From the looks of the average driveway or sidewalk, it may seem as though concrete is just destined to crack. But if concrete is so prone to cracking, how are we able to use it in so many high-stress applications like bridges and skyscrapers? This question came about while I was researching 3D-printed thermite for an article. Thermite is often used in welding railroad tracks, and I linked a video of fresh tracks being welded that had concrete ties. I knew I had to find out how concrete could be made to withstand the pressure of freight trains.
On its own, concrete is brittle and has no give to it at all. But that doesn’t mean it isn’t strong. Although concrete has good compression strength, the tensile strength is quite poor. Around the late 1800s, someone thought to fortify spans of concrete with steel reinforcing bars, better known as rebar. Steel can stretch, adding steel bars gives the concrete some tensile strength to go along with its compressive strength. Rebar also allows for thinner slabs and other members.
Rebar Only Goes So Far
Parking blocks are meant to be replaced occasionally. Image via Checkers Safety
Rebar or mesh-enforced concrete is good for things like parking lot blocks and roads, but it still fails before it ought to. In fact, it usually has to crack before the rebar can chip in any of its tensile strength.
In high-stress concrete applications like bridges and skyscrapers, it’s terrifically important to avoid deflection — that’s when a concrete member flexes and bends under load. Deflection can cause the modern glass skins to pop off of skyscrapers, among other problems.
A solid, rigid bridge is much nicer to walk, drive, and bicycle on than a bridge that sways in the breeze. But how do you do make a rigid bridge? One solution is to apply stresses to the concrete before it ever bears the load of cars and trucks or a steady schedule of freight trains.
Pre-stressed concrete is like rebar-enforced concrete, but with the added power of tension baked in. By adding stress to the concrete before it goes into service, deflection will be reduced or perhaps eliminated altogether. With the addition of tensile strength, more of the concrete’s own strength is able to come into play.
In the dawning of the IBM PC era, the computer case was a heavy, stout thing. These were industrial machines, built with beefy paddle power switches, and weighing as much as a ton of bricks. Painted in only the ugliest beige, they set the tone for PC design for the next couple of decades.
At the turn of the millennium, the winds of change swept through. The Apple iMac redefined the computer as a hip, cool device, and other manufacturers began to reconsider their product aesthetics. Around the same time, the casemodding scene took off in earnest, with adherents building ever wilder battle stations for internet clout and glory.
With all the development that has gone in the last 40 years of the PC platform, we’ve seen great change and improvement in almost every area. But in building a new rig this past month, this writer discovered there’s one element of the modern PC that’s still trapped in the past.
By now, you’ve likely heard that scientists have found a potential sign of biological life on Venus. Through a series of radio telescope observations in 2017 and 2019, they were able to confirm the presence of phosphine gas high in the planet’s thick atmosphere. Here on Earth, the only way this gas is produced outside of the laboratory is through microbial processes. The fact that it’s detectable at such high concentrations in the Venusian atmosphere means we either don’t know as much as we thought we did about phosphine, or more tantalizingly, that the spark of life has been found on our nearest planetary neighbor.
Venus, as seen by Mariner 10 in 1974
To many, the idea that life could survive on Venus is difficult to imagine. While it’s technically the planet most like Earth in terms of size, mass, composition, and proximity to the Sun, the surface of this rocky world is absolutely hellish; with a runaway greenhouse effect producing temperatures in excess of 460 C (840 F). Life, at least as we currently know it, would find no safe haven on the surface of Venus. Even the Soviet Venera landers, sent to the planet in the 1980s, were unable to survive the intense heat and pressure for more than a few hours.
While the surface may largely be outside of our reach, the planet’s exceptionally dense atmosphere is another story entirely. At an altitude of approximately 50 kilometers, conditions inside the Venusian atmosphere are far more forgiving. The atmospheric pressure at this altitude is almost identical to surface-level pressures on Earth, and the average temperature is cool enough that liquid water can form. While the chemical composition of the atmosphere is not breathable by Earthly standards, and the clouds of sulfuric acid aren’t particularly welcoming, it’s certainly not out of the realm of possibility that simple organisms could thrive in this CO2-rich environment. If there really is life on Venus, many speculate it will be found hiding in this relatively benign microcosm high in the clouds.
In short, all the pieces seem to be falling into place. Observations confirm a telltale marker of biological life is in the upper levels of the Venusian atmosphere, and we know from previous studies that this region is arguably one of the most Earth-like environments in the solar system. It’s still far too early to claim we’ve discovered extraterrestrial life, but it’s not hard to see why people are getting so excited.
But this isn’t the first time scientists have turned their gaze towards Earth’s twin. In fact, had things gone differently, NASA might have sent a crew out to Venus after the Apollo program had completed its survey of the Moon. If that mission had launched back in the 1970s, it could have fundamentally reshaped our understanding of the planet; and perhaps even our understanding of humanity’s place in the cosmos.
