Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Comments

top

Power Grids: The Huge Battery Market You Never Knew Existed

aaarrrgggh Re:Yes, we know that. (148 comments)

You are mixing units to your detriment-- think in kW not kWh. You are also incorrect regarding efficiency; when you pay for your demand up front efficiency is much more incentivized.

3 hours ago
top

Airbnb To Hand Over Data On 124 Hosts To New York Attorney General

aaarrrgggh Re:It is a public safety issue (149 comments)

See, the rules work! ;)

On a serious note though, fire regulations are only one of many differences; accessibility, ventilation, energy all are different between long term and short term housing.

about a week ago
top

Munich Council Say Talk of LiMux Demise Is Greatly Exaggerated

aaarrrgggh Re:LibreOffice (190 comments)

The GP is referring to the classic problem of collaborating with a single document. Party A provides base information, B edits information, A reviews changes and makes further updates. Collaborating with a PDF is called markup, and relies on a single party to be responsible for editing. Not sure if Google Docs does a good enough job on resumes yet to work.

about a week ago
top

Airbnb To Hand Over Data On 124 Hosts To New York Attorney General

aaarrrgggh Re:It is a public safety issue (149 comments)

Because transient residents are not intimately familiar with the fire escapes and layout of the building. Smoke compartments must be smaller, low-level exit signs are generally required (so someone can see them when crawling), and requirements for secondary exits are different. And... you must post a sign at the door indicating exit locations.

I am torn on the issue; in a place like San Francisco or NYC, the issue of taking units out of the rental pool is quite serious. This becomes worse where you have rent control. On the flip side, it is nice to have options when you stay in a place without sufficient traditional lodging offerings. Bed and breakfast establishments aren't really my cup of tea personally, but having a small apartment or house for a few days can put you more in the center of a community.

about a week ago
top

For Microsoft, $93B Abroad Means Avoiding $30B Tax Hit

aaarrrgggh Re:Okay... and? (316 comments)

It is hard to make that work in the US because taxes for a person and corporation are essentially treated the same (sans FICA/FUTA). This eliminates many of the easy tax shelters for individuals; a low corporate tax rate re-opens these issues.

about a week ago
top

For Microsoft, $93B Abroad Means Avoiding $30B Tax Hit

aaarrrgggh Re:Okay... and? (316 comments)

While it has been 15 years since I had to deal with this, using your numbers you would owe no US taxes. You exclude the first roughly $100,000 in income, so the US would see your income as $100k, and you paid $68k in taxes already, and would have only owed about $25k in the US.

The only gotcha is that you need to spend less than 35 days in the US per year.

The capital gains is a bit of a bitch if you have anything meaningful, but that is a the price of entry into the US market.

about a week ago
top

It's Easy To Hack Traffic Lights

aaarrrgggh Re:Welcome to the Information Age! (144 comments)

There is one option; the PLCs fail to a "safe" mode and ignore the network if the validation PLC (not networked) detects an anomaly. Stoplight timing is out the window, but green lights in all directions would not be possible.

about two weeks ago
top

It's Easy To Hack Traffic Lights

aaarrrgggh Re:Welcome to the Information Age! (144 comments)

I started to rebut your comment... but then actually came to agree. The cost of fixing this problem is huge; any traffic light pedestal could be an entry point from a "trusted" point on the system, and I have seen several in Los Angeles unlocked. Effectively the problem is reduced to if you have physical access to the machine there isn't much you can do for security.

about two weeks ago
top

Is Storage Necessary For Renewable Energy?

aaarrrgggh Re:Some can be done - and is. Most is bull. (442 comments)

The PV Watts gives ambient temperature and wind speed data in the hourly CSV output, and I just created a formula to calculate available wind energy for the given wind speed and turbine efficiency. The microhydro was just a basic reserve calculation on my elevation change, reservoir volumes, and average monthly rainfall; my intent was to try and use it as a dump load as well, but it wasn't effective.

The project included a greenhouse, desalinization system, and I was cooling a thermal mass during the afternoon when I had available power. The desalinization system could run for 3 hours and generate 24 hours of water consumption, not 3 hours at peak load.

How many days are you planning for a battery? I found I didn't have many discretionary loads that could be deferred for more than 3 days which drove storage substantially when I wanted to limit generator run time; I needed it 80+ days per year with a 3-day battery.

There are likely some math errors on demand side (especially looking at installed HP for some motors rather than going to the trouble to calculate BHP), but the general results seem rational.

about two weeks ago
top

Researchers Find Security Flaws In Backscatter X-ray Scanners

aaarrrgggh Re:This is ridiculous. (146 comments)

Nineteen people taking out 3500...

...out of some 5+ billion that have walked through US airport security checkpoints since. Out of (pessimistically) 50,000 people with the will or propensity to inflict ill will via items contained on their person or in their luggage on others. (And arguably 5 that could be successful on a given trip.) ...At a cost of countless millions of wasted hours, billions of wasted dollars, and fundamentally liberty lost.

Pretty good for the contractors though...

about two weeks ago
top

Is Storage Necessary For Renewable Energy?

aaarrrgggh Re:Some can be done - and is. Most is bull. (442 comments)

I modeled a quad-gen system with 4kW PV on 2-axis trackers, a 3kW wind turbine, 1kW micro-hydro, and a 2kW genset. Annual energy consumption was 7.5MWh. Batteries were sized at 25kWh; the micro-hydro could do 20kWh storage. I had some substantial demand-side flexibility due to a RO system that was sized to handle peak demand with 3 hours of operation per day, thermal storage, and a few other tricks. Peak demand was 5kW.

The PV System produced 86% of the needed power, and wind 12%. The micro-hydro was primarily backup, and was adequate for all but 6 hours per year when the generator was required. In practical use the generator would likely need to operate more when other components were out of service.

The point of this is that I needed 2x capacity vs peak demand, and 11x for average demand, even with tremendous flexibility in demand-side control. While the wind saves a few cycles on the battery per year, at least two thirds of the energy produced would be burnt up by the load dump. The microhydro was a waste and would never justify the cost; likely much more environmentally friendly to just get another generator.

The lowest capital cost solution for me would be a 6kW PV Tracker and a 65kWh battery, along with the 2kW genset, but I would be generating 30% more power than I could use most days. Running the numbers isn't that hard; even taking grid stability issues out of the equation it is clear that you are stuck with a substantial energy storage issue, either in the form of thermal or chemical.

about two weeks ago
top

Is Storage Necessary For Renewable Energy?

aaarrrgggh Re:Some can be done - and is. Most is bull. (442 comments)

I would suggest taking a look at the 8760-hour output of the NREL PV Watts program; it is enlightening. For me, if I sized a PV array at 150% capacity (best-day production vs average demand), I would need 80 hours of generator backup per year if my battery were sized for 3-days demand. If I have 7-days, I would only need a generator for 4 hours per year of generator.

The bottom line is that you need substantial excess capacity and a huge geographic diversity to be able to get by on renewables alone. Think 400% or so. That is incredibly inefficient.

about two weeks ago
top

Reversible Type-C USB Connector Ready For Production

aaarrrgggh Re:One of the most frustrating first-world problem (191 comments)

The cable connection at the lightning connector has failed on me several times, specifically because the connector stays connected to the device. The removal force exceeds the strength of the cable. Yes, I understand you shouldn't pull from the cable, but the connector body is sometimes too small to get a good hold on.

about three weeks ago
top

Reversible Type-C USB Connector Ready For Production

aaarrrgggh Re:One of the most frustrating first-world problem (191 comments)

As an Apple customer, I am quite happy they ditched the "30-pin" connector and went with the reversible lightning connector. One less thing to fiddle with when charging my phone. Nice to see USB picking up the feature, even if it is a couple years later with implementations still not available.

That said, the cable/connector interface on the lightning cables is not nearly strong enough for the insertion/removal force required. It will be interesting to see if the USB design will work better in that regard, as the shield does provide some mechanical latching.

about three weeks ago
top

Comcast Drops Spurious Fees When Customer Reveals Recording

aaarrrgggh Re:What about Oregon and Washington? (368 comments)

Use speaker phone. Once you are on speaker, there is no assumption of privacy. Once there is no assumption of privacy, then you can record... at least in California.

about three weeks ago
top

What Do You Do When Your Mind-Numbing IT Job Should Be Automated?

aaarrrgggh Re:And who the fuck will maintain it? (228 comments)

Not just documentation about the automation, but also making sure that the original mind-numbing manual process is properly documented! I would also say there should be an intermediate level of documentation between the manual process and the automated process indicating how it ideally should work.

When today's needs change, having the path to work back to how the original came to be is critical.

about three weeks ago
top

With Chinese Investment, Nicaraguan Passage Could Dwarf Panama Canal

aaarrrgggh Re:Money pit (322 comments)

For reference, a big excavator today for mining can go over 40 cubic meters

about three weeks ago
top

TEPCO: Nearly All Nuclear Fuel Melted At Fukushima No. 3 Reactor

aaarrrgggh Re:So.. what? (255 comments)

CO2 causes acidification of the oceans, which is a much bigger problem than the greenhouse effect, and will happen much sooner than the point where atmospheric CO2 levels become toxic to humans.

about three weeks ago
top

States That Raised Minimum Wage See No Slow-Down In Job Growth

aaarrrgggh Re:Local testing works? (778 comments)

Some people are bad with money and make stupid life decisions. No wage or training will fix it.

My office manager makes almost $75k, and financed a used car at 19% interest, even after I explained how to calculate the interest to her. She is 40 and a grandma. She gets a bonus and uses it to buy seasons pass at a theme park. I think a few country songs were written about her....

about a month and a half ago

Submissions

Journals

aaarrrgggh has no journal entries.

Slashdot Login

Need an Account?

Forgot your password?

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>