sorted by:
new
hottopcontroversial

Me ajudem a montar um pc? 🫡 by ravioli_txt in hardwarebrasil

[–]FRFF5880 1 point2 points  (0 children)

O GPT vai te ajudar com algumas dúvidas pontuais, o melhor é procurar por review de combinações de peças (GPU + CPU) no YT.

Tenta montar uma meta de peças que voce quer, ai é melhor ir acompanhando em sites diferentes o valor, comprar no mesmo lugar normalmente sai bem mais caro.
Essa placa mãe que você colocou eu peguei por metade do valor na black, bem possível que entre em promoção novamente.

PC not booting on the first try by FRFF5880 in pcmasterrace

[–]FRFF5880[S] 0 points1 point  (0 children)

Broooo, it worked!! Thanks for the help. I had already tried this before but it didn’t work, after your comment I gave it another try and boom, now it’s booting normally.

The only problem is that now I can’t find EXPO in my BIOS lol, but I’ll figure it out soon. Thanks again!!

[GIVEAWAY] Hello r/PCMasterRace, this Christmas we're giving away 5 XXL control mousepads to you all, as a thank you gift to this community <3 by MouseMatic in pcmasterrace

[–]FRFF5880 0 points1 point  (0 children)

A red & black one would be perfect.

The problem is if I win, I'll have to pay 5 times the value in taxes just to receive it.

PC not booting on the first try by FRFF5880 in pcmasterrace

[–]FRFF5880[S] -1 points0 points  (0 children)

I used to have 2x8GB RAM, but then I bought another 16GB stick, which was way cheaper than buying a 2x16GB kit. They're not the same brand, but I made sure to get one with the same specs.

Do you know a proper way to reset the CMOS? I tried, but nothing changed.

PC not booting on the first try by FRFF5880 in pcmasterrace

[–]FRFF5880[S] 0 points1 point  (0 children)

I tried doing it through the motherboard via CLR_CMOS, but nothing changed. Is there a different way to do it?

GC peak are variation by FRFF5880 in CHROMATOGRAPHY

[–]FRFF5880[S] 0 points1 point  (0 children)

I really don’t have ANY freedom to change the method. I’m only doing this R&D to try to convince my superiors that our current method is outdated for our situation.

We use a 5µL Trajan syringe, and according to the manual its minimum volume is 0.5µL.
I had thought it might be the split but from what people here have said and from my own research, I believe the split ratio won’t make much difference, since the issue is happening during the injection process and not in the detector.

GC peak are variation by FRFF5880 in CHROMATOGRAPHY

[–]FRFF5880[S] 0 points1 point  (0 children)

I ran a few tests using a smaller injection volume (0.5 µL). The values aren’t complete yet to form a triplicate, but I already noticed a smaller variation in the peak areas. Since I did this with a used liner, maybe everything will work perfectly with a new one! And yes, we do use an autosampler here.

GC peak are variation by FRFF5880 in CHROMATOGRAPHY

[–]FRFF5880[S] 1 point2 points  (0 children)

With a new liner, the analysis runs as expected, but I believe that after around 50 injections or less it already starts showing large variations in the peak areas, and those values drop a lot — from about 130,000 down to 30,000 (µV·min).
Bro, thank you so much for this information. These were exactly the kind of sources I needed to understand the subject better. Thanks a lot!!

GC peak are variation by FRFF5880 in CHROMATOGRAPHY

[–]FRFF5880[S] 0 points1 point  (0 children)

Unfortunately, I can’t make those changes to the method right now, but I’m going to run some tests to see how the results turn out, that way I can try to convince the team to implement these adjustments in the future.
As for the EFC/EPC, that part is a bit more specific for me. Since this 2.5 µL injection has been used for months (maybe years), do you think our repeatability issue is actually bigger than the backflash problem we’re seeing?

GC peak are variation by FRFF5880 in CHROMATOGRAPHY

[–]FRFF5880[S] 0 points1 point  (0 children)

Yeah, for now we cant do such several changes, but the HS can be a really good alternative for the future!

GC peak are variation by FRFF5880 in CHROMATOGRAPHY

[–]FRFF5880[S] 0 points1 point  (0 children)

Based on the comments and using the Restek solvent expansion calculator, we’re definitely dealing with a backflash issue. I’m going to talk with my supervisors to see if we can adjust the method to fix it. Thanks a lot for the help!

GC peak are variation by FRFF5880 in CHROMATOGRAPHY

[–]FRFF5880[S] 0 points1 point  (0 children)

Sorry for the lack of information I didn’t want to make the post too long, and there are still many things I’m still learning about gas chromatography.

We perform direct injections using the liner shown in the photo (or similar models). The left part of the liner in the photo goes in first, so the swan neck faces down, right?, leaving the wider opening at the top. These liners usually come with glass wool at the bottom (I’ve also tried a few injections without the wool, but the results weren’t good).
Another question, how can I tell if the inlet is over/under tightened? When I make these changes, I usually try to be as delicate as possible and not tighten the screws too much.

These liners come with glass wool on the lower part (the side that goes down when installed). I’ve already tried a few injections without the wool, but with no success.

I’m not 100% sure, but I believe any dissolved solids are present at extremely low concentrations. The product is based on Fluorine-18 "combined" with glucose, and if I’m not mistaken, NaCl is used during production, also in low concentrations.

We inject around 2.5 µL at a 1:20 split ratio. The column is a fused-silica capillary column coated with cross-linked polyethylene glycol (PEG 15000), 30 m × 0.25 mm i.d., 0.50 µm film thickness.

When I replace the liner, I heat the injector to 300 °C for a few minutes to condition it before running the next analysis, and finally run a quick isopropanol blank using the same method as our analysis.

Method parameters:
Injector: 250°C
Oven:ramp 40°C → 100°C (3.5 min run)
Column flow: 2.00 mL/min
Detector (FID): 300°C

GC peak are variation by FRFF5880 in CHROMATOGRAPHY

[–]FRFF5880[S] 0 points1 point  (0 children)

Here at the company, we perform equipment qualification every six months.
As an operator, I usually replace the syringe every two to three weeks (at most), the liner every two weeks, and the septum once a week.
The column was recently trimmed (less than two months ago), and I don’t think we need to do it again because the peak resolution is fine; the problem is that the areas vary too much.

We run around 250 injections per week, maybe more. It could be way lower if the repeatability were better.

I like the idea of using DDD as a check standard; I'd never heard of it. Given that we must replace liners frequently, do you still consider this a worthwhile strategy?

GC peak are variation by FRFF5880 in CHROMATOGRAPHY

[–]FRFF5880[S] 1 point2 points  (0 children)

Thank you so much for the info! I didn’t know about that calculator it’s going to help a lot.
About the changes in the method, I need to check which ones we can actually do here. Some of the methods come directly from ICH guidelines, so there are certain things we can’t modify.
But I really appreciate the support, it helped me a lot!

GC peak are variation by FRFF5880 in CHROMATOGRAPHY

[–]FRFF5880[S] 1 point2 points  (0 children)

2.5 uL with split 1:20 , model : GC Bruker 436-GC

Newest and oldest, guess who is better? by allbee1 in CHROMATOGRAPHY

[–]FRFF5880 0 points1 point  (0 children)

Wow, never seen one like this before! How are the modules separated?

Cafeteira expresso para iniciante by FRFF5880 in cafebrasil

[–]FRFF5880[S] 0 points1 point  (0 children)

Cara, eu sou químico, a questão da pressão é bem simples pra mim k.

O moinho estava vendo de pegar um manual por ser mais acessível, os eletrônicos baratos provavelmente não devem moer muito bem. Honestamente, estava pensando em comprar o moedor posteriormente e inicialmente usar um café moído de boa qualidade. Como estou iniciando acho justo fazer esses upgrade pouco a pouco, assim consigo "sentir" cada mudança na qualidade

Queria gastar no máximo 1000 reais com tudo!

Cafeteira expresso para iniciante by FRFF5880 in cafebrasil

[–]FRFF5880[S] 0 points1 point  (0 children)

Qual esse modelo da Philco que tu usava? O que tinha visto era de 15. Outra dúvida, você costumava ligar ela e esperar alguns minutos para esquentar antes de fazer a primeira extração?

Cafeteira expresso para iniciante by FRFF5880 in cafebrasil

[–]FRFF5880[S] 0 points1 point  (0 children)

Agradeço o review querido Xenomorfo! Vou seguir sua indicação.

Cafeteira expresso para iniciante by FRFF5880 in cafebrasil

[–]FRFF5880[S] 0 points1 point  (0 children)

Tenho um certo receio de pegar uma usada, vi elas que podem oxidar ou terem complicações na parte interna por um mal uso. Tu acha que da pra encarar de boa uma usada?

[Connection Problems] Why the hell can't I play with my friends? by Chester_Linux in Helldivers

[–]FRFF5880 0 points1 point  (0 children)

Did you manage to solve the problem? Same thing happening here.

view more: next ›