u/SolidRaider

Hi.

Waters UPLC Aquity H Class.

Last post, yesterday, I received many help and I took everything into consideration and wanted to share results. i'm very new at this. Problem is: high and unstable pressure of the system. Always rising Here we go with today's tests:

Tests 1, 2 and 3: Replacing column with a fitting, and purging 4 lines with MeOH, and then monitoring pressure with flux increments until 1 ml/min. Test 2 was the same but with ACN. Test 3 same but using working mixture: solvent A: 0,1% formic in water and solvent B: 100% ACN. The system runs in a 70:30 mixture of A and B. below picture with ACN.

https://preview.redd.it/g5qhe4cjshah1.png?width=1280&format=png&auto=webp&s=0dc230cd0c97db6417caa38f94e8d0d09860d629

Pressure is steady, reaching it's value quickly too in all cases and remaining steady. difference is: in Test 3 there is a "clack-clack" coming from the valve which receives all 4 solvents tubings. it's 2 noises, seems like an "open-close" of a valve, and it accompanies the bomb cycle. 1 bomb cycle = 2 "clacks". seems quite normal since it's mixing A and B, but I'm not used to the noise, maybe it's a bit noisier than normal.

Well, that being said, the system seems to perform bad or well?

For us is well, so we proceeded to insert the column, which made things don't work quite well: Pressure stills rising. Using that 70:30 mixture, we slowly went to work flux, which is 0.4 ml/min. Pressure has been arround 10600 and has a delta of ~50, without stabilizing ever, and again slowly - slowly- rising. in 15 minutes of writing this, now is 10800 psi.

https://preview.redd.it/bsec7qmlshah1.png?width=1280&format=png&auto=webp&s=66c939d18b95315f4253e653faa52243a131c1e7

Could we say this is a column issue, or would that be a rushed and erratic conclusion?

extra!

in the test without column, we noticed that the system pressure has a little oscilation (around 10 psi) when pressure is below 600 psi. is that normal? after 600 psi it seems to accomodate with an oscilation of 2-3 psi only. it does it regardless of the solvent. it's perfectly coordinated with bomb sounds. a picture here:

https://preview.redd.it/d5wlnewgshah1.png?width=1599&format=png&auto=webp&s=d4cd962c8303a9320cf13dfd8e97ee3d2232ee4d

Thanks very much!!

Hello there. I'm completely new at this.

At my lab, we have a Waters Aquity class H, and run a mixture: 70 0,1% formic in water(solvent A) : 30 acetonitrile (solvent B). flux 0.4 ml/min. C is methanol.

The UPLC has been used previously by another branch of the company, and it was installed here a month ago, and validated by a technician. but unfortunately, last week we saw this:

1. Pressure with 70:30 is higher than usual: +12000 psi at work flux, where it should be around 8000.
2. Pressure with 70:30 mixture is unstable, and seems to be always slowly rising. whilst with 100% acetonitrile, it reaches a value and remains very steady. for example, at 0.1 flux, it achieves 900 psi in 30 seconds, while using 70:30 goes to 2600 psi and starts going up... it can go 15 minutes and still rising.

we purged the column with acetonitrile a lot, also backflushed it in case we contaminated it, and no results. Finally we used another column. But the same replicates in both columns... which is very weird for a novice like me.

We did some leak tests, surprisingly solvent A (water with 0,1% formic) passess accumulator and primary tests. But B and C pass only the acumulator test, not the primary. Leak rate is 460 nL/min and 213 nL/min could that test have something to say?

I'm currently sonicating the check valve in methanol, thanks to a suggestion of laboratory boss.

please let me know if there is information I'm missing in order to clarify. best, thanks in advance!

Estoy queriendo vender la moto en Salta Capital y solamente hay a partir del 15 de julio 🤌🏻.

Cómo puede ser tanta demora?

Hey all,

I’m currently shooting barebow with a Gillo GX riser and WNS Delta C2 32 lb carbon foam limbs (about 33 lb on the fingers), using uncut Victory VAP V6 700 spine arrows. I’m planning to move up to 36 lb eventually as I advanced to 50 m.

Right now I also know my arrows are on the weak side. I’ll be replacing them eventually, but I might do it before changing limbs.

My main questions:

1. Is it safe and mechanically fine to run these 32 lb limbs up to ~36 lb using the limb bolts on a GX riser, or does that push the limbs outside their intended working range? (I still have ~3 turns available. Gillo states ±15% adjustment is possible, but I’m not sure how this holds up in practice.)

2. For tuning and consistency, is it better to stay near the minimum bolt setting (as I currently am), or is it actually preferable to use more of the adjustment range and increase preload if needed?

3. For a future upgrade at 36 lb, what would be a meaningful step up in limb quality without going straight to top-tier? Any recommendations on models or materials (carbon foam vs wood core vs other) would be appreciated.

Please keep in mind prices in Argentina are absolutely crazy, so when I say one step better than my limbs, I really mean it.

Thanks a lot!

Buenas!

Mi pareja (1,57 m) quiere comprarse una bici más que nada para andar por la ciudad. Quisieramos que no sea algo berreta (no renegar con cosas de mala calidad) pero obviamente tampoco necesitamos lo mejor de Shimano.

Nos recomendaron BICICLETA SPY BULLET SPORT 29ER 1X9 TURQUESA TALLE S pero sale $789.000. Obviamente que es una buena bici y cumple, pero para mí algo como: BICICLETA SPY BULLET SPORT 21V MEC 2026 también va como piña y por $472.000

¿qué opinan de eso? y sientanse libres de sugerir otras también por favor!

Presupuesto máximo: aldededor de $500.000.

También dudas:

• Pensamos comprar talle S, ¿pero el rodado qué onda? para 1,57 m
• Si la horquilla amortiguadora no es muy buena y bloqueable, es un pijazo andar. Y antes que eso, en la ciudad, convendría una fija. ¿qué opinan?

Gracias!

Buenas cómo están? me llegó un mail diciendo que debo patente de hace como 4 años de la moto, lo cual es imposible porque ya tuve que pagar todas las patentes cuando hice la transferencia y la vendí, y encima la cambié de provincia en la venta (ni loco te dejan cambiarte de provincia si no tené todo pago en la anterior)

La moto fue comprada en Santa Fe y vendida en Salta. Además la compra venta se terminó correctamente y ya no figuro como titular de la moto.

A alguien más le pasó lo mismo??

Hello. I'm having this problem (aluminium thred with brass screw). The hexagone for the allen wrench is totally rounded. I tried to do some little indents (top and down) to put a flat screwdriver but it's not happening.

Now I'm planing to put WD-40 and then use a screw extractor.

Was thinking also of heating the aluminium previous to use the screw extractor, but I don't know if it would benefit the operation.

I wanted to know if any of you had some similar experience and how did you manage to solve it.

Note: The screw is a grub screw, that pressures against a stainless steel bolt. The entire piece is an riser (archery), which it would be very important to preserve.

https://preview.redd.it/pg1j5zbg9k3h1.jpg?width=1311&format=pjpg&auto=webp&s=2044bd3a1fe00451cd3e218a4a8486741b7626ff

Hello. I'm having this problem with my riser. (Gillo GX - aluminium with brass screw). The hexagone for the allen wrench is totally rounded. I tried to do some little indents (top and down) to put a flat screwdriver but it's not happening.

Now I'm planing to put WD-40 and then use a screw extractor.

Was thinking also of heating the aluminium previous to use the screw extractor, but I don't know if it would benefit the operation.

I wanted to know if any of you had some similar experience and how did you manage to solve it.

Note: The screw is a grub screw, that pressures against the limb bolts.

Note2: The bow works well, the limb bolt is firm, and I can even tight/loosen it. It also has another grub screw on the other side. But I would like to solve this.

Hello there!

I've been struggling really hard in aiming decently at those distances. At 30 m I get mostly all 10 and 9, sometimes an 8. (let's say every 12 arrows, comes an 8)

At 30 m I align eye-arrow-target, and can see the entire target at the sides of the string (string is in the middle). Whenever I shot bad it's because of bad release or torquing the bow, which is also noticeable in the arrow flight. But in the end, I do feel really aware of where I'm shooting.

But at 40 the target just dissapears behind the string and hence it feels like very random.

Any suggestions? Bad concept of aiming? I've heard it's supposed to be more "a feeling", but it just doesn't seem right when the entire target disappears behind the string.

Edit: THANKS! For all the answers, they're really helpful.

I’m a chemist currently working in analytical labs (ICP-MS, ion chromatography, some early UPLC experience) and I’ve been approached for a Technical Sales role for analytical instrumentation in an important company.

The role would involve customer interaction, demos, travel, technical consulting, and sales responsibilities across different industries.

I already explained them that I don't have background in the thing they're looking, but anywat they seem very interested in me. "You know the technic part, we form you in commercial". And also during the first months I would work among with previous person in that rol.

For people who made the transition from lab work to technical sales/application roles in analytical instrumentation:

Did you enjoy the change? Do you still feel technically connected to science/instrumentation? Any regrets or things you wish you knew beforehand?

I’m genuinely interested in the company and rol, but that would be a major career/life shift for me, so I’d appreciate honest opinions.

Hello everybody. I want to upgrade sound quality. I have a JBL Flip 1 which sounds much better than generic Hanxo speakers in my PC, but I want to go a step further. I hear hard rock mainly, blues, jazz and some metal. I see a movie sometime, but main objective would be music for the moment.

Questions:

1. Can I start with with a 2.0 system and then maybe in the future add a subwofer if I want it?
2. I was thinking in Edifier, which one would you say have the best value per money? Let's say I'm looking for something clearly better than my JBL Flip 1 but spending the less possible. Feel free to recommend other brands, I will check prices since I live in Argentina and prices are high and distorted.

• R1100 - ~US$160
• MR3 - ~US$182
• QR30 - ~US$192
• R1280T - ~US$201
• MR4 - ~US$240
• M60 - ~US$246
• R1280DB - ~US$250
• R1280DBS - ~US$290
• R1700BTS - ~US$344
• MR5 - ~US$386
• R2000DB - ~US$437

I would prefer to stay below 350 USD, just added the others because if they really worth it I could consider it.

Thanks in advance!

https://preview.redd.it/t92ox1dbf50h1.png?width=1280&format=png&auto=webp&s=015624539624a78ba2cd5e3c02c8db94f80e670c

Hi everyone, I just found a video Battery change JBL Flip 1 and changed the battery, that seem to have solved the problem of the speaker turning off in 3-5 minutes while playing music, whether the battery was charged (blue light) or not (red light). It was like if it didn't recognize music was being played.

Thing is: when I dissassembled it, I found that extension of the picture, and it makes me curious about it's function. It goes out from the chipboard through a red&black wire, and goes right into the plastics of the speaker. Could that be a sensor to determine wheter the speaker is playing music or not?

Thanks in advance.

Edit: ya le saqué 40 ml y ahora marca bien. Aparentemente me pasé y debí purgar mejor el aceite viejo.

---‐--------------------------

Buenas, hoy hice mi primer cambio de aceite.

Salió aprox 920 ml del viejo.

Cargué el litro nuevo y mido con la varilla, y me da que está excedido, supera por dos milímetros el máximo. Medí 3 veces, bien derechita la moto. Y fue post encendido, apagado y esperar un par de minutos, como dice el manual.

¿Será que debí esperar más a que se le vaya el aceite viejo? Ya goteaba cuando volví a ponerle el tapón, capaz debí dejarla gotear más.

https://preview.redd.it/fb27ho5rztxg1.jpg?width=720&format=pjpg&auto=webp&s=0169c624b8a69a52aba05113f0ece374c4a6af42

https://preview.redd.it/40o6omerztxg1.png?width=992&format=png&auto=webp&s=ec13f5c43184f62ab3860d4c289621a75b10105d

Hi everybody.

Months ago I lost that piece (picture 1). You can see the full rest in the picture 2.

what would it's function be? seems like a grub screw but I'm not sure. Knowing it's function would give me a better idea on how to replace it.

thanks!