Tootfinder

#AmateurRadio Field Day is coming, and I am but a baby ham who wants to try to work #CW on field day, but would like a little practice first.
Morse Walker has an

A tunable, continuous-wave 130-mW laser at 213 nm
Lukas M\"oller, Stephan Hannig, Stefan Truppe, Simon Stellmer
https://arxiv.org/abs/2506.08709 https…

A tunable, continuous-wave 130-mW laser at 213 nm
We present a tunable, continuous-wave (CW) laser system emitting at 213 nm, based on the frequency quadrupling of a single Ti:sapph laser. The setup features two sequential, cavity-enhanced second-harmonic generation (SHG) stages. The first stage uses an LBO crystal and achieves a conversion efficiency of over 80%, yielding up to 3.3 W at 426 nm. The second stage employs a Brewster-cut BBO crystal with an elliptical beam waist to mitigate UV-induced degradation, producing up to 130 mW of deep U…

The Acorn, our local newspaper, had a nice article on CVARC's Field Day...in the first photo, those are phone stations on the right, digital on the left, and CW operators in the next tent in the distance. I try to keep the digital and CW operators separated, because...well, if you know, you know. :wink:
https://www.

Still really loving the Insta 360 camera, so easy to make nice things
https://youtu.be/c8YH-oBs-cw

@… #HC24S — Over the past few days, I made and improved a PR adding Field Day support to the Open Source #MorseWalker #CW …

this is very cool! you can embed UV glow powder into your body and have it glow in the dark after light exposure
[cw: blood, pictures of wounds] https://bioduck.me/2025/06/03/glow-powder-cuttings/
(via @…

Glow Powder Cuttings!
Glowing cuttings have been around for a while. Spyfoxls tried it many years ago. Now more people in the Biohackers Digital Discord have picked it up again and started sharing results. Several folks…

This https://arxiv.org/abs/2502.13276 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

CW-complexes and minimal Hilbert vector of graded Artinian Gorenstein algebras
I introduce a geometric interpretation of the set of standard graded Artinian Gorenstein algebras of codimension $n$ and degree $d$: the standard locus, which is a subset of the projective space of degree $d$ polynomials in $n$ variables, and I characterize it. Under opportune hypothesis, I prove that the locus of full Perazzo polynomials is the union of the minimal dimensional irreducible components of the standard locus and it is pure dimensional subset. On the other hand, I associate to any …

Significance of soft-scale breaking on primordial black hole production in Coleman-Weinberg type supercooling-phase transition
He-Xu Zhang, Katsuya Hashino, Hiroyuki Ishida, Shinya Matsuzaki
https://arxiv.org/abs/2506.23752

Significance of soft-scale breaking on primordial black hole production in Coleman-Weinberg type supercooling-phase transition
Ultra-supercooling phase transitions can generate large overdensities in the Universe, potentially leading to the formation of primordial black holes (PBHs), which can also be a dark matter candidate. In this work, we focus on the supercooling phase transition for the scale symmetry breaking based on the effective potential of the Coleman-Weinberg (CW) type. We investigate the effect on the PBH production in the presence of an additional mass term for the CW scalar field, what we call a soft-sc…

Taken just a few minutes ago. Where?
CW guesses or answers. Be as precise as possible.
#osint #geolocation #CatchMeIfYouCan

Free actions on products of real projective spaces
Ergun Yalcin
https://arxiv.org/abs/2506.04067 https://arxiv.org/pdf/2506.04067

Free actions on products of real projective spaces
We prove that if $G=(\mathbb{Z}/2)^r$ acts freely and cellularly on a finite-dimensional CW-complex $X$ homotopy equivalent to $\mathbb{R}P ^{n_1} \times \cdots \times \mathbb{R} P ^{n_k}$ with trivial action on the mod-$2$ cohomology, then $r \leq μ(n_1)+ \cdots + μ(n_k )$ where for each integer $n\geq 0$, $μ(n)=0$ if $n$ is even, $μ(n)=1$ if $n\equiv 1$ mod 4, and $μ(n)=2$ if $n\equiv 3$ mod 4. This proves a homotopy-theoretic version of a conjecture of Cusick.

Useful info to our instance members (and anyone really) about the "mutual aid spam":
https://enby.life/notes/a9de58bd33

Hazelnoot (@hazelnoot)
CW: fedi PSA, spam, mutual aid scam (📎1)

Lense-Thirring Precession Modulates Repeated Lensing of Continues Gravitational Wave Source from AGN Disks
Yu-Zhe Li, Wen-Long Xu, Yi-Gu Chen, Wei-Hua Lei
https://arxiv.org/abs/2506.04196

Lense-Thirring Precession Modulates Repeated Lensing of Continues Gravitational Wave Source from AGN Disks
Gravitational lensing of gravitational waves (GWs) offers a novel observational channel that complements traditional electromagnetic approaches and provides unique insights into the astrophysical environments of GW sources. In this work, we investigate the repeated lensing of continuous gravitational wave (CW) sources in active galactic nucleus (AGN) disks by central supermassive black holes (SMBHs), focusing on the imprint of SMBH spin via the Lense-Thirring (LT) effect. Although typically wea…

Advancing Atmospheric Pollution Monitoring with Airborne THz Spectrometer
Candida Moffa, Alessandro Curcio, Camilla Merola, Daniele Francescone, Marco Magi, Massimiliano Coppola, Lucia Giuliano, Mauro Migliorati, Massimo Reverberi, Leonardo Mattiello, Massimo Petrarca
https://arxiv.org/abs/2507.00943

Advancing Atmospheric Pollution Monitoring with Airborne THz Spectrometer
This study details the development and validation of an airborne THz spectrometer designed for real-time, remote detection of atmospheric pollutants. The platform couples a stabilized unmanned aerial system (UAS) with a high-resolution terahertz continuous-wave (THz-CW) laser source and detector, enabling flexible, in situ spectroscopic analysis of dispersed atmospheric vapours. This proof-of-concept investigation confirms the feasibility of UAS-THz-CW systems for spatially resolved environment…

Bloody assholes.

The MIST-1 and MIST-2 multicusp ion sources for high-current H$_2^ $ beams
Daniel Winklehner, Samuel Engebretson, Jarrett Moon, Joshua Villarreal, Philip Weigel, Eleanor Winkler, Parker landon
https://arxiv.org/abs/2507.03155

The MIST-1 and MIST-2 multicusp ion sources for high-current H$_2^+$ beams
We present two iterations of the Multicusp Ion Source Technology at MIT (MIST) sources, designed to fulfill the requirements of the HCHC-XX cyclotron design. The HCHC-XX is a novel compact cyclotron accelerating H$_2^+$. Beam is injected through a radio-frequency quadrupole buncher-accelerator (embedded in the cyclotron yoke) and utilizes so-called vortex motion during acceleration. If successful, it will deliver 10 mA of protons at 60 MeV in CW mode. This scheme requires a low-emittance, high-…

On measure homology of mildly wild spaces
Thilo Kuessner, Janusz Przewocki, Andreas Zastrow
https://arxiv.org/abs/2506.03368 https://…

On measure homology of mildly wild spaces
We prove injectivity of the canonical map from singular homology to measure homology for certain ``mildly wild" spaces, that is, certain spaces not having the homotopy type of a CW-complex, but having countable fundamental groups.

CHESS Compact Wiggler construction report
Alexander Temnykh, Ivan Temnykh
https://arxiv.org/abs/2505.24585 https://arxiv.org/pdf/2505…

CHESS Compact Wiggler construction report
We developed, built, characterized on bench and beam-tested a permanent magnet (PM) Compact Wiggler (CW) prototype with a hydraulic assist gap-controlling mechanism. The prototype is of ~50cm long, 20cm wide and 40cm high and weights ~50kg. Magnetic structure has a 76.2mm period. At 6.5mm minimal gap the structure demonstrated ~2.3 Tesla peak field. At this gap, the magnet arrays attract each other with 7,990 N (1,796 lbf) force. Hydraulic system is employed to balance the attractive forces. He…

I tried hunting POTA with five different #HamRadio antenna arrangements while taking a short holiday at the beach over the past few days. I tried the built-in antenna on my KX3, a 20m vertical with radials on a deck, the same vertical with radials stuck with a stake into the top of a sand dune, and two inverted-V 40m end-fed half wave arrangements on a spiderbeam, a north/south and an e…

This https://arxiv.org/abs/2312.13227 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

Relative cell complexes in closure spaces
We give necessary and sufficient conditions for certain pushouts of topological spaces in the category of Cech's closure spaces to agree with their pushout in the category of topological spaces. We prove that in these two categories, the constructions of cell complexes by a finite sequence of closed cell attachments, which attach arbitrarily many cells at a time, agree. Likewise, the constructions of CW complexes relative to a compactly generated weak Hausdorff space that attach only finitely m…

I wish I'd known of this video before I started trying to hunt #POTA. It's so helpfully thorough and systematic. The past few days would have been a lot easier for me if I'd watched it before.
Anyone here who is learning #CW and thinking of trying to hunt POTA, this is totally worth yo…

Combined frequency comb and continuous wave cavity-enhanced optical-optical double-resonance spectrometer in the 1.7 ${\mu}$m range
Vinicius Silva de Oliveira, Adrian Hj\"alt\'en, Isak Silander, Andrea Rosina, Michael Rey, Kevin K. Lehmann, Aleksandra Foltynowicz
https://arxiv.org/abs/2506.17669

Combined frequency comb and continuous wave cavity-enhanced optical-optical double-resonance spectrometer in the 1.7 $μ$m range
We present an optical-optical double-resonance (OODR) spectrometer based on a 3.3 $μ$m continuous wave pump and two cavity-enhanced probes: a frequency comb tunable in the 1.64 - 1.8 $μ$m range, and a comb-referenced continuous wave (CW) laser tunable in the 1.6 - 1.75 $μ$m range. The comb probe provides broad spectral coverage (bandwidth up to 7 THz) for simultaneous detection of many sub-Doppler OODR transitions with sub-MHz line position accuracy, while the CW probe allows targeting indiv…

A New cw-NMR Q-meter for Dynamically Polarized Targets for Particle Physics
J. D. Maxwell, J. Brock, C. Cuevas, H. Dong, C. D. Keith, J. J. Pierce
https://arxiv.org/abs/2506.14637

A New cw-NMR Q-meter for Dynamically Polarized Targets for Particle Physics
Polarized solid targets produced via Dynamic Nuclear Polarization rely on Continuous-Wave Nuclear Magnetism Resonance measurements to accurately determine the degree of polarization of bulk samples polarized to nearly 100%. Since the late 1970's phase sensitive detection methods have been utilized to observe the magnetization of a sample as a small change in inductance under RF excitation near the Larmor frequency of the nuclear species of interest, using a device known as a Q-meter. Liverpool …

Quantitative Macromolecular Proton Fraction Imaging using Pulsed Spin-Lock
Qianxue Shan (Department of Imaging and Interventional Radiology), Ziqiang Yu (Department of Imaging and Interventional Radiology), Baiyan Jiang (Department of Imaging and Interventional Radiology, Illumination Medical Technology Limited), Jian Hou (Department of Imaging and Interventional Radiology), Qiuyi Shen (Department of Imaging and Interventional Radiology), Winnie CW Chu (Department of Imaging and Interv…

Quantitative Macromolecular Proton Fraction Imaging using Pulsed Spin-Lock
Purpose: Recent studies have shown that spin-lock MRI can simplify quantitative magnetization transfer (MT) by eliminating its dependency on water pool parameters, removing the need for a T1 map in macromolecular proton fraction (MPF) quantification. However, its application is often limited by the requirement for long radiofrequency (RF) pulse durations, which are constrained by RF hardware capabilities despite remaining within specific absorption rate (SAR) safety limits. Methods: To addres…

Baby's First #AmateurRadio #FieldDay! I ran the GOTA station for a few minutes to warm it up, and again in the early morning after the night crew were done for a handful of QSOs, but I spent many hours in the CW tent. At the start I just froze up and needed lots of help from th…

A Fox-Neuwirth Basis for the Sinha Spectral Sequence
Andrea Marino
https://arxiv.org/abs/2505.22958 https://arxiv.org/pdf/2505.22958

A Fox-Neuwirth Basis for the Sinha Spectral Sequence
Recently, Sinha defined a spectral sequence approximating the (co)homology of the space of long knots in R^m modulo immersions, stemming from a cosimplicial structure on the compactified configuration spaces à la Kontsevich. We provide an equivalent cosimplicial structure on (the barycentric subdivision of) a regular CW complex with cells indexed by Fox-Neuwirth trees. As a corollary, we give a combinatorial presentation of the Sinha Spectral Sequence in terms of Fox-Neuwirth trees for all dim…

Youtube comment handling is so annoying.
HRCC talked about Field Day, including some mention of CW. So I mentioned my Morse Walker Field Day simulator work, and Josh pinned my comment.
I have now twice posted followup comments mentioning QRZ and my call sign, hoping that people can find the simulator from my QRZ page, without posting a link, and Youtube keeps silently deleting the comments. Argh.
I have no idea what it is triggering on.
Meanwhile,