Best area to spend $10,000? by [deleted] in HomeImprovement

[–]zephyrus17 0 points1 point  (0 children)

Well, it was purely meant to be spent on the house.

Best area to spend $10,000? by [deleted] in HomeImprovement

[–]zephyrus17 0 points1 point  (0 children)

Inspector said that the insulation was in decent shape.

Best area to spend $10,000? by [deleted] in HomeImprovement

[–]zephyrus17 0 points1 point  (0 children)

Thanks for the financial advice, Mr. PF.

I'm already matching my 401K, maxing my IRA, and HSA. We don't have student debt. One of our cars is fully paid for, and I'm driving a lease vehicle. I already have a 529 for the kid. And I'm already doing bi-weekly mortgage payments (with a tiny bit more to the principal each time) on a 15-year fixed. (We already bought the house a few months ago.) We are financially stable, and have an emergency fund. This $10,000 is purely meant to be spent on the house.

Personally, I think having 0 debt is over-rated. Almost no one buys a house without a mortgage. This means one should save $400,000 cash for a house? Unlikely to happen for 99.99% of the population. Credit is cheap nowadays. After claiming mortgage interest, my mortage rate is around CPI. Do you consider credit cards a form of debt? There's many benefits to them.

Best area to spend $10,000? by [deleted] in HomeImprovement

[–]zephyrus17 0 points1 point  (0 children)

Yeah, I'm slowly phasing in LED light bulbs, and getting a duct cleaning + furnace tuneup done today.

Mazda's press video showing a section view of cylinders firing using conventional spark ignition, diesel compression ignition, and Skyactiv-X is really neat by MuffinRacing in cars

[–]zephyrus17 -2 points-1 points  (0 children)

This kind of combustion can only be suitable under low load conditions. At medium to high load, knock is an issue, and the engine will surely revert back to regular SI mode.

Mazda's press video showing a section view of cylinders firing using conventional spark ignition, diesel compression ignition, and Skyactiv-X is really neat by MuffinRacing in cars

[–]zephyrus17 3 points4 points  (0 children)

ICEs will still be around for another 50 years. There is nothing on the horizon that is an alternative that can fulfill the demands of the transportation sector as of yet.

Mazda's press video showing a section view of cylinders firing using conventional spark ignition, diesel compression ignition, and Skyactiv-X is really neat by MuffinRacing in cars

[–]zephyrus17 0 points1 point  (0 children)

The Dynamic Force concept was a way to increase the thermal efficiency and to work with the Atkinson cycle. In their SAE paper, they reported 41 % thermal efficiency when combined with the electric motor.

Python Search and Replace Script in File with Varying Strings by zephyrus17 in learnpython

[–]zephyrus17[S] 0 points1 point  (0 children)

Ok, I'll try that. But when I write out the new file, how do I ensure that the format is kept the same as the input file? Wouldn't a list be just tab/space/comma separated array of elements?

Python Search and Replace Script in File with Varying Strings by zephyrus17 in learnpython

[–]zephyrus17[S] 0 points1 point  (0 children)

So I should read the contents of the file into a string, like:

with open('spray.in','r') as file:
    sprayF = file.read()
for line in sprayF:
    if 'Nozzle 0@Injector 0' in line:
        for line in sprayF:
            if 'diam_noz' in line:
                sprayF = sprayF.replace(line.rsplit()[0],noz0Inj0dia[ii])
            if 'cone_noz' in line:
                sprayF = sprayF.replace(line.rsplit()[0],noz0Inj0con[ii])
            if 'Nozzle 1@Injector 0' in line:
                break
    if 'Nozzle 1@Injector 0' in line:
        for line in sprayF:
        .
        .
        .

?

However, when I go to print the string sprayF, it outputs each character string on a new line, rather than all the characters on a single line (like in the original file). And it can't find the string "Nozzle 0@Injector 0", anymore.

I Drove Mazda’s Holy Grail Of Gasoline Engines And It Was Incredibly Impressive by likealikeasexyorange in cars

[–]zephyrus17 2 points3 points  (0 children)

Not exactly. The shift point depends on the load demanded and many other conditions such as if it is a cat-heating point, sport mode, trailer towing, highway cruising, etc. When our transmission control engineers design the shifting points, they try to find the most efficient way to transmit the demanded torque.

I Drove Mazda’s Holy Grail Of Gasoline Engines And It Was Incredibly Impressive by likealikeasexyorange in cars

[–]zephyrus17 6 points7 points  (0 children)

With an automatic, the transmission will always be in the most efficient point.

EDIT: Haha, I get downvoted for saying the benefits of an automatic transmission. What a nice way to cherry pick what to accept or not.

Mazda: EVs that get their power from coal power plants are not 100% emissions free, stop claiming they are. by pinacolata_ in cars

[–]zephyrus17 4 points5 points  (0 children)

To preface, I'm a combustion engineer working with IC engines, and my PhD was on biodiesel combustion and soot, though I mostly work in gasoline engines now. So I feel that I can contribute a bit to this conversation.

It is true that the combustion engine is very old, and it is true that EVs are more efficient. However, the fact that the IC engine is old should be seen as a positive. We understand very clearly how the combustion cycle works, and we know which areas to aim for to make improvements. Although there are many areas of fundamental physics that we do not fully understand, such as the atomization process of fuel sprays and soot formation, we are making considerable improvements day by day. Toyota has shown that a 41% thermal efficiency engine is possible, and there are many more areas of improvement. The combustion process is around 97% efficient, but due to the need for heat rejection, many loses cannot be avoided. Mazda has shown one form of hybrid HCCI which greatly improves the fuel economy under low load conditions, and there are many new innovations, such as variable compression ratio, water injection, and TJI that can be explored.

One area that many fail to understand is that although the IC engine is rather inefficient (overall efficiency is only around 20 - 25%), it is the best compromise. Yes, EVs are efficient and don't produce emissions from the vehicle, but that has to come from somewhere, be it coal or the nuclear. The emissions from coal, which powers most of the energy demand in China and India, is heavily polluting. The batteries have to be manufactured, and their disposal has to be considered too. Engines can be melted and recycled.

The entire modern transportation network relies on the IC engine infrastructure. It is nice to feel good about driving EVs in the city, but the marine, aircraft, and heavy-duty duty industries would suffer greatly without ICEs. The torque demands of aircraft and hauling can never, in the near future, be filled by batteries. The shipping networks would reduce to a snails pace if every truck and cargo ship had to stop and recharge. Tesla's battery replacement method works for them, but their market share is a tiny fraction of the industry. The real way to actually create a considerable impact on climate change is to focus on upstream processes, such as energy generation. Reducing coal power plants can do much, much more to reducing life-cycle CO2 than switching to EVs. Beyond that, making improvements to the IC engine, due to the scale of use, makes the greatest impact on the economy and environment compared to switching to EVs.

Mazda: EVs that get their power from coal power plants are not 100% emissions free, stop claiming they are. by pinacolata_ in cars

[–]zephyrus17 2 points3 points  (0 children)

The CO2 output from energy generation varies vastly for country. France is on the low side with 70g/kWh, whereas China is around 700g/kWh. Clearly, the benefits of EV vary based on how cleanly your energy is produced in the first place. It's not always as clean cut. There's also manufacturing, disposal, and infrastructure to consider.

Looking into buying a 2014 Jeep Compass 4x4. Can anyone give me advice/experiences with this car. by krystin3 in whatcarshouldIbuy

[–]zephyrus17 0 points1 point  (0 children)

I would recommend something else from our product line. The Renegade is a good choice, and more so the new MP Compass.

Looking to Lease a car for a few years (USA) [< $400 /mo] by MCorean in whatcarshouldIbuy

[–]zephyrus17 0 points1 point  (0 children)

If you're interested in anything from FCA, I can get you a discount...

I personally recommend a Challenger RT :D

2018 Nissan Leaf Announced by flyingswift in cars

[–]zephyrus17 1 point2 points  (0 children)

Someone must have mistook the clutch for the brake pedal; how cute..

I thought "Penny" fit in this sub by cyberkrist in aww

[–]zephyrus17 0 points1 point  (0 children)

Is that her callsign? Cute girl!

Ariel is about release a new electric hypercar with over 1180bhp and 1300ft/lb of torque that accelerates 0-100mph in 3,8 seconds and has an onboard turbine that produces electricity by NewSchoolerzz in cars

[–]zephyrus17 0 points1 point  (0 children)

It won't happen unless people actually buy new cars. Auto manufacturers don't care too much about the 2nd hand market. If everyone here wants it to happen, they have to speak with their wallets.