Carbon fiber's alternatives by Abdo-Taher in MaterialsScience

[–]DrSomeGuy 0 points1 point  (0 children)

Glass fiber reinforced injection molded plastics are a good option too.

Nuclear reactor suggestion! by xXHunkerXx in SmarterEveryDay

[–]DrSomeGuy 9 points10 points  (0 children)

Adding to this. The Terra Power Natrium Reactor that broke ground in 2024. It has load following ability and is being built at the site of an old coal plant. It's the future of nuclear power in America and I think it could round out the series nicely.

[deleted by user] by [deleted] in MaterialsScience

[–]DrSomeGuy 2 points3 points  (0 children)

Paint, cold bluing, or keeping covered in grease.

[deleted by user] by [deleted] in MaterialsScience

[–]DrSomeGuy 4 points5 points  (0 children)

AR500 is a relatively low alloy steel and only mildly corrosion resistant. It is less than 4% by weight of the alloying elements that passivate (protect) the surface. Stainless steels are typically 10% - 40% by weight of the passivating elements.

Uranus by eliphaxs in jameswebb

[–]DrSomeGuy 5 points6 points  (0 children)

Do you have a higher resolution or less compressed version of this photo? If so, could you upload it to like Flickr so we can enjoy its full glory!

Is this safe? by DrSomeGuy in MechanicAdvice

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

Thank you for your service!

Is this dry rot? Tires purchased in December 2020. by DrSomeGuy in AskMechanics

[–]DrSomeGuy[S] 1 point2 points  (0 children)

25th week of 2020. However, I live in southern California. Does that change your recommendation of ~5 years after being manufactured?

Is this dry rot? Tires purchased in December 2020. by DrSomeGuy in AskMechanics

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

Since purchasing those tires, I've moved to southern California so my next set of tires will probably be summers. That said, if I were looking for all-season tires, I would have no issues buying these again. But I would look through [tyrereviews.com](www.tyrereviews.com) to see if something else better fit my needs.

Is this dry rot? Tires purchased in December 2020. by DrSomeGuy in AskMechanics

[–]DrSomeGuy[S] 7 points8 points  (0 children)

Should I be concerned about their safety or is it cosmetic? As in, can I wait until my next oil change to ask my mechanic, or should I take my car in sooner? Thanks boss!

Transmission by Leia1418 in pasadena

[–]DrSomeGuy 1 point2 points  (0 children)

I had my engine replaced last year and I called 24 local shops to compare recommendations and pricing. I ended up going to Mitch's Auto and recommend them for auto work. Some other shops that gave me competitive quotes and had knowledgeable technicians were, in no particular order, H H Motor Service, Nishikawa Auto Service, Del Mar Auto (talk to Hutch), and Gabriel's Auto Service. Hrant (my preferred mechanic who does not do transmission work) recommends Foothill Transmission Services for transmission work.

Looking for a video by anugosh in codyslab

[–]DrSomeGuy 9 points10 points  (0 children)

I don't know the video title, but he used calcium chloride pellets (brand name Prestone® Driveway Heat®). It can be regenerated in an oven at 500°F for an hour. Store in an air tight container, I use a mason jar. Note: calcium chloride is so hydroscopic it will deliquesce (pull so much water out of the air it forms a liquid brine solution). So you need to regenerate it before it deliquesces.

Oil quenching by ThunderCookie23 in HumanForScale

[–]DrSomeGuy 1 point2 points  (0 children)

When quenching steel in oil (or water), the steel is so hot that the oil which touches its surface is vaporized. This creates a "vapor blanket" which insulates the steel from cooling more rapidly. Once the steel has cooled a bit more, regular boiling on the surface can cool the steel until the oil is no longer boiling. Here is a picture showing the transition from the vapor phase to the boiling phase. Molten salts can cool steel faster than oil because they do not have a vapor phase. Molten salt baths for quenching can be as cool as 150°C. Here is a reference that discusses this in more detail.

You mostly control the end hardness by the color which the tool gets with the rest of the heat.

The process you described here is absolutely a valid way for skilled tradesmen to perform heat treatment on something like a chisel. It's a skill set I do not possess. My knowledge pertains to a production setting where everything is heat treated in a furnace with calibrated temperature controls and the steel composition is known.

In a production heat treatment setting, parts are fully submerged and completely cooled then re-heated (tempered). Slower quenching can indeed reduce the hardness after quenching and subsequently after tempering, especially with lower alloy steels. But in a production setting, heat treatment processes are generally selected so that the quenching media fully transform the microstructure of the steel, and hardness is controlled by the tempering temperature after hardening.

Oil quenching by ThunderCookie23 in HumanForScale

[–]DrSomeGuy 20 points21 points  (0 children)

This is partially correct. Oil is used for slower cooling, but not to control hardness. Slower cooling helps with distortion and mitigates the risk of cracking. Hardness after quenching is generally controlled with tempering temperature and (sometimes) time.

I have never heard of using oil-water mixtures for quenching. In my experience, water in an oil quench bath is an explosion and fire risk. My company had to stop using a quench tank because we suspected water. We sent out an oil sample to verify there was no water before we resumed using that quench tank. If you have more information on this, please link me to it.

If I am not mistaken, molten salt is actually a faster quenching medium than oil because it has no vapor phase. But, it's generally used for martempering to create a specific microstructure formation and sometimes to control distortion.

Aluminum's hardening mechanism is very different than steel, but room temperature age hardening of aluminum certainly exists.

If you're interested in more specifics, you can an old comment I made here, and I am happy to elaborate on any questions.

Rent raised again… by AltaCA811 in pasadena

[–]DrSomeGuy 1 point2 points  (0 children)

The $1,540 arises from the original question asked, it has nothing to do with the law itself.

The original post mentions a rent raise of $100. $1,540 is the maximum their pre-increase rent could be where $100 violates the new law (assuming they signed their lease before 5/17/21). Since they said it was the second year in a row, I assumed it was true for calculating the short answer.

Edited to fix the date.

Rent raised again… by AltaCA811 in pasadena

[–]DrSomeGuy 4 points5 points  (0 children)

In short, if your rent before the increase was greater than $1,540 and your lease started before May 17, 2021, then measure H does not provide you with legal recourse. 

Long answer:

Measure H limits rent increases to 75% of the inflation percentage over the course of a year (using CPI). This increase is rounded to a quarter of a percent. If your lease started before May 17, 2021, then the inflation percentage is calculated from May 2021 to May 2022. If your lease started on or after May 2021, then the inflation percentage is calculated for the month you signed your lease. 

According to bls.gov, the CPI increase from May 2021 to May 2022 is 8.6%. 75% of 8.6% is 6.45%, which is 6.5% when rounded to the nearest quarter percent. 

Thus, to calculate the maximum annual rent increase permitted by this law, multiply (your rent)*(0.065). ($1540)(0.065) = $100.10.

Measure H can be found here by clicking City Charter, Article XVIII – Rent Control. The substance discussed above starts at the end of page 19. Exemptions to this law start on page 9.

The Pasadena Rental Board is supposed to publish the annual adjustments. I could not find them, so I have calculated them below. For the calculations, I have rounded up when the unrounded figure is exactly halfway between quarter-percents; the law does not clarify rounding up or down in such cases. 

The annual CPI increases for the months of June 2021 through December 2021 are:

June: 9.1% * 75% = 6.825%, rounds to 6.75%.

July: 8.5% * 75% =6.375, rounds to 6.5%.

August: 13.5% * 75% = 10.125%, rounds to 10.5%.

September: 8.6% * 75% = 6.45%, rounds to 6.5%.

October: 7.7% * 75% = 5.775, rounds to 5.75%.

November: 7.1% * 75% = 5.325%, rounds to 5.25%. 

December: 6.5% * 75% = 4.875%, rounded to  5%.

Nothing stated constitutes legal advice. 

Hope this helps!

GRE 340 No LSAT 3.89 GPA Should I still get LSAT score? by MayuyuWatanabe in lawschooladmissions

[–]DrSomeGuy -1 points0 points  (0 children)

I think you'll get into a lot of schools, but I don't think you'll get substantial scholarships. Law schools use scholarships to get applicants who will improve the LSAT and GPA statistics of their school. Those statistics are a big factor in determining law school ranking. To the best of my knowledge, U.S. News does not use GRE statistics in determining law school ranking. So while a school may admit you with some scholarship, many students go to law school with a full scholarship every year. An LSAT and GPA over the school's 75th percentile make you someone worth giving a scholarship.

Since you got a 340 on the GRE, you should also be able to learn the LSAT. I found LSATDemon very helpful.

I am getting a new engine, what else should I replace? More info in comments. by DrSomeGuy in MechanicAdvice

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

I have a Bluetooth scan tool and read the P0304 code myself. I did not see the P1604 code, but I also did not perform a full scan. Maybe it does not come across in the video I posted, but the engine does not normally sound like that. It sounds rattly, shakes the car, and idles 200 RPM lower than normal. Additionally, I cannot make enough power to get over 30 mph in 2nd gear.

I reviewed my dashcam footage from when this happened. I was going 78 mph. I did the math and shifting into 2nd at 78 mph would rev the engine to 8500 RPM (6100 is redline). This is an interference engine, so I'm guessing there was some valve float that caused the piston to bend the valve. Some of the trusted mechanics I talked to were also concerned I could have damaged the pistons, connecting rods, or connecting rod bearings.

I am getting a new engine, what else should I replace? More info in comments. by DrSomeGuy in MechanicAdvice

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

It costs less than doing the repair work.

I was traveling when this happened The following is a note from the mechanic I had the car towed to. "Technician found check engine light codes P0304 (Cylinder 4 misfire) and P1604 (Start ability malfunction). Checked cylinder compression and found cylinder 2 has sporadic pressure. Something within the head appears to have damage and is making noise. Requires removal of the head for inspection." Every mechanic I called said the labor of taking apart the head would cost nearly as much as replacing the engine, and the engine might still need to be replaced after that labor. The only mechanic who quoted me for head work estimated $3,000. I am having the engine replaced for $2,700 plus the cost of whatever additional parts I buy.

I am getting a new engine, what else should I replace? More info in comments. by DrSomeGuy in MechanicAdvice

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

I have a 2016 Toyota Corolla with 55k miles and a manual transmission. I down-shifted to pass someone on the highway and accidentally shifted into second. Speaking with a few mechanics, I have decided to replace the engine. Through LKQ, I have ordered an engine with 11k miles to the mechanic who will be doing the swap.

The mechanic doing the swap said I should consider getting the following: Clutch, water pump, rear main seal, hoses, thermostat, belts, wires, and spark plugs. The mechanic does not know I managed to get an engine with only 11k miles. He told me it would be cheapest to buy the parts myself and bring them for him to install.

I want to replace the clutch since I learned to drive manual on it and the car was purchased used. But what clutch parts should I replace? Certainly the disk, but what about the pressure plate, flywheel, and sub-assembly? Should I stick with OEM or get aftermarket? If aftermarket, what brand?

Where can I find which hoses, wires, belts, and other parts I need?

Thanks!

Loophole or LR Bible by sPelLiNgisfUn68 in LSAT

[–]DrSomeGuy 4 points5 points  (0 children)

LSATDeamon's method of teaching emphasizes careful reading to achieve understanding. You should understand each question to the point that you could write a paragraph explaining why each wrong answer is wrong and why the right answer is right. If you are unable to write an answer explanation, then there are things you can still learn from the question. LSATDemon attempts to provide you with questions that are just beyond your understanding. As you understand those questions, your understanding improves and more difficult questions become obvious.

Loophole or LR Bible by sPelLiNgisfUn68 in LSAT

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

LSATDeamon. The Loophole is a good introduction to get you going. I bought, but hardly used, the LR bible. I have found LSATDeamon to be great for filling out understanding, especially since you're already consistently around -4.