TFINER is an Atompunk Solar Sail Lookalike
It’s not every day we hear of a new space propulsion method. Even rarer to hear of one that actually seems halfway practical. Yet that’s what we have in the case of TFINER, a proposal by [James A. Bickford] we found summarized on Centauri Dreams by [Paul Gilster] .
TFINER stands for Thin-Film Nuclear Engine Rocket Engine, and it’s a hoot. The word “rocket” is in the name, so you know there’s got to be some reaction mass, but this thing looks more like a solar sail. The secret is that the “sail” is the rocket: as the name implies, it hosts a thin film of nuclear materialwhose decay products provide the reaction mass. (In the Phase I study for NASA’s Innovative Advanced Concepts office (NIAC), it’s alpha particles from Thorium-228 or Radium-228.) Alpha particles go pretty quick (about 5% c for these isotopes), so the ISP on this thing is amazing. (1.81 million seconds!)Figure 3-1 From Bickford’s Phase I report shows the basic idea.
Now you might be thinking, “nuclear decay is isotropic! The sail will thrust equally in both directions and go nowhere!”– which would be true, if the sail was made of Thorium or Radium. It’s not; the radioisotope is a 9.5 um thin film on a 35 um beryllium back-plane that’s going to absorb any alpha emissions going the wrong way around. 9.5um is thin enough that most of the alphas from the initial isotope and its decay products (lets not forget that most of this decay chain are alpha emitters — 5 in total for both Th and Ra) aimed roughly normal to the surface will make it out.
Since the payload is behind the sail, it’s going to need a touch of shielding or rather long shrouds; the reference design calls for 400 m cables. Playing out or reeling in the cables would allow for some degree of thrust-vectoring, but this thing isn’t going to turn on a dime.
It’s also not going to have oodles of thrust, but the small thrust it does produce is continuous, and will add up to large deltaV over time. After a few years, the thrust is going to fall off (the half-life of Th-228 is 1.91 years, or 5.74 for Ra-228; either way the decay products are too short-lived to matter) but [Bickford]’s paper gives terminal/cruising velocity in either case of ~100 km/s.
Sure, that’s not fast enough to be convenient to measure as a fraction of the speed of light, and maybe it’s not great for a quick trip to Alpha Centauri but that’s plenty fast enough for to reach the furthest reaches of our solar system. For a flyby, anyway: like a solid-fueled rocket, once your burn is done, it’s done. Stopping isn’t really on offer here. The proposal references extra-solar comets like Oumuamua as potential flyby targets. That, and the focus of the Sun’s gravitational lens effect. Said focus is fortunately not a point, but a line, so no worries about a “blink and you miss it” fast-flyby. You can imagine we love both of those ideas.
NASA must have too, since NIAC was interested enough to advance this concept to a Phase II study. As reported at Centauri Dreams, the Phase II study will involve some actual hardware, albeit a ~1 square centimeter demonstrator rather than anything that will fly. We look forward to it. Future work also apparently includes the idea of combining the TFINER concept with an actual solar sail to get maximum possible delta-V from an Oberth-effect sundive. We really look forward to that one.
Repairing a Tektronix 577 Curve Tracer
Over on his YouTube channel our hacker [Jerry Walker] repairs a Tektronix 577 curve tracer.
A curve tracer is a piece of equipment which plots I-V (current vs voltage) curves, among other things. This old bit of Tektronix kit is rocking a CRT, which dates it. According to TekWiki the Tektronix 577 was introduced in 1972.
In this repair video [Jerry] goes to use his Tektronix 577 only to discover that it is nonfunctional. He begins his investigation by popping off the back cover and checking out the voltages across the voltage rails. His investigations suggest a short circuit. He pushes on that which means he has to remove the side panel to follow a lead into the guts of the machine.
Then, in order to find the shorted component he suspect exists, [Jerry] breaks out the old thermal cam. And the thermal cam leads to the fault: a shorted tantalum capacitor, just as he suspected to begin with! After replacing the shorted tantalum capacitor this old workhorse is like new.
There are probably quite a number of repair lessons in this video, but we think that an important takeaway is just how useful a thermal camera can be when it comes time for fault finding. If you’re interested in electronics repair a thermal cam is a good trick to have up your sleeve, it excels at finding short circuits.
If you’re interested in repairing old Tektronix gear be sure to check out Repairing An Old Tektronix TDS8000 Scope.
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Chess.com: come un tool di file transfer ha esposto i dati di migliaia di utenti
@Informatica (Italy e non Italy 😁)
Nel panorama dei servizi online, poche piattaforme possono vantare la stessa pervasività e fedeltà degli utenti di Chess.com. Con oltre 100 milioni di iscritti e 10 milioni di partite organizzate ogni giorno, il sito è il cuore pulsante del gioco degli
In sentencing memos and exhibits, Pratt's attorney paints of picture that points at Pratt's abusive father, his ADHD, his co-conspirators, the entire pornography industry, and the victims themselves.
In sentencing memos and exhibits, Prattx27;s attorney paints of picture that points at Prattx27;s abusive father, his ADHD, his co-conspirators, the entire pornography industry, and the victims themselves.#girlsdoporn
Giorgio Armani: la grandezza e l’umiltà
@Giornalismo e disordine informativo
articolo21.org/2025/09/giorgio…
Con la scomparsa di Giorgio Armani ci dice addio una certa idea di moda, una certa idea di Milano e anche una certa idea d’Italia. Armani, infatti, era un uomo colto, partito dal basso e rimasto umile per tutta la vita. Piacentino, classe 1934, si è affermato
Tips for Homebrewing Inductors
How hard can it be to create your own inductors? Get a wire. Coil it up. Right? Well, the devil is definitely in the details, and [Nick] wants to share his ten tips for building “the perfect” inductor. We don’t know about perfect, but we do think he brings up some very good points. Check out his video below.
If you are winding wire around your finger (or, as it appears in the video, a fork) or you are using a beefy ferrite core, you’ll find something interesting in the video.
Of course, the issue with inductors is that wires aren’t perfect, nor are core materials. Factors like this lead to inefficiency and loss, sometimes in a frequency-dependent way.
It looks like [Nick] is building a large switching power supply, so the subject inductor is a handful. He demonstrates some useful computational tools for analyzing data about cores, for example.
We learned a lot watching the tricks, but we were more interested in the inductor’s construction. We have to admit that the computed inductance of the coil matched quite closely to the measured value.
Need a variable inductor? No problem. Before ferrite cores, good coils were a lot harder to wind.
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Dal governo via libera a “scudo penale” per i medici: perseguibili solo per colpa grave
Lo prevede un disegno di legge delega. Il Consiglio dei Ministri ha anche approvato il nuovo decreto sull'esame di maturitàRedazione di Rainews (RaiNews)
Francesca Albanese e le sanzioni Usa: "Chi ha rapporti con me rischia 20 anni di carcere"
La relatrice speciale dell'Onu spiega le ripercussioni delle misureRedazione Adnkronos (Adnkronos)
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A hacker has compromised Nexar, which turns peoples' cars into "virtual CCTV cameras" that organizations can then buy images from. The images include sensitive U.S. military and intelligence facilities.
A hacker has compromised Nexar, which turns peoplesx27; cars into "virtual CCTV cameras" that organizations can then buy images from. The images include sensitive U.S. military and intelligence facilities.#News
rilanciamo la mobilitazione con una nuova due giorni di raccolta firme
Sabato 6 e domenica 7 torniamo nelle piazze per cancellare i poteri speciali grazie ai quali Gualtieri gioca la partita con un mazzo di carte truccato. Contro l'abuso di potere legalizzato puoi metterci la firma. Nella locandina trovi dove e quando firmare. Massima diffusione 💪🏼
404 Media first revealed ICE’s new app, called Mobile Fortify, in June. Now members of a congressional committee are pressing DHS for more information, including ICE's legal basis for using the app inside the U.S.
404 Media first revealed ICE’s new app, called Mobile Fortify, in June. Now members of a congressional committee are pressing DHS for more information, including ICEx27;s legal basis for using the app inside the U.S.#Impact
Designing an Open Source Micro-Manipulator
When you think about highly-precise actuators, stepper motors probably aren’t the first device that comes to mind. However, as [Diffraction Limited]’s sub-micron capable micro-manipulator shows, they can reach extremely fine precision when paired with external feedback.
The micro-manipulator is made of a mobile platform supported by three pairs of parallel linkages, each linkage actuated by a crank mounted on a stepper motor. Rather than attaching to the structure with the more common flexures, these linkages swivel on ball joints. To minimize the effects of friction, the linkage bars are very long compared to the balls, and the wide range of allowed angles lets the manipulator’s stage move 23 mm in each direction.
To have precision as well as range, the stepper motors needed closed-loop control, which a magnetic rotary encoder provides. The encoder can divide a single rotation of a magnet into 100,000 steps, but this wasn’t enough for [Diffraction Limited]; to increase its resolution, he attached an array of alternating-polarity magnets to the rotor and positioned the magnetic encoder near these. As the rotor turns, the encoder’s local magnetic field rotates rapidly, creating a kind of magnetic gear.
A Raspberry Pi Pico 2 and three motor drivers control this creation; even here, the attention to detail is impressive. The motor drivers couldn’t have internal charge pumps or clocked logic units, since these introduce tiny timing errors and motion jitter. The carrier circuit board is double-sided and uses through-hole components for ease of replication; in a nice touch, the lower silkscreen displays pin numbers.
To test the manipulator’s capabilities, [Diffraction Limited] used it to position a chip die under a microscope. To test its accuracy and repeatability, he traced the path a slicer generated for the first layer of a Benchy, vastly scaled-down, with the manipulator. When run slowly to reduce thermal drift, it could trace a Benchy within a 20-micrometer square, and had a resolution of about 50 nanometers.
He’s already used the micro-manipulator to couple an optical fiber with a laser, but [Diffraction Limited] has some other uses in mind, including maskless lithography (perhaps putting the stepper in “wafer stepper”), electrochemical 3D printing, focus stacking, and micromachining. For another promising take on small-scale manufacturing, check out the RepRapMicron.
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Thanks to [Nik282000] for the tip!
Berichte über Überwachung in Gaza: Microsoft entlässt Mitarbeitende nach Protesten
libramenteblog.blogspot.com/20…
libramenteblog.blogspot.com/20…
Editoria scolastica: pubblicato il rapporto preliminare dell’Autorità Garante della Concorrenza e del Mercato
Editoria scolastica: pubblicato il rapporto preliminare dell’Autorità Garante della Concorrenza e del Mercato
L’Autorità Garante della Concorrenza e del Mercato ha reso nota nel bollettino 30/2025 del 04/08/2025 la pubblicazione di un due provvedimenti sull’editoria scolastica e di un interessante allegato al provvedimento, recante il rapporto preliminare sull’editoria scolastica che analizza in profondità le dinamiche economiche e strutturali del settore.
Il termine per la conclusione del procedimento è stato prorogato al 31 dicembre 2025.
L’indagine nasce esattamente un anno fa dalla necessità di comprendere meglio come vengono adottati, distribuiti e utilizzati i libri di testo nelle scuole italiane, con particolare attenzione ai costi sostenuti dalle famiglie e all’effettiva transizione verso il digitale.
Il mercato dell’editoria scolastica in Italia ha un valore stimato di circa 800 milioni di euro, con pochi grandi gruppi editoriali che dominano l’offerta. Nonostante la crescente disponibilità di contenuti digitali, la modalità più diffusa resta quella mista, che combina il libro cartaceo con contenuti online. Tuttavia, l’utilizzo effettivo delle risorse digitali è ancora molto limitato: solo una piccola percentuale delle licenze viene attivata e gli accessi alle piattaforme sono sporadici. Questo evidenzia una transizione digitale incompleta, ostacolata da carenze infrastrutturali, scarsa formazione del personale docente e da sistemi chiusi che limitano la condivisione e la flessibilità.
Il rapporto sottolinea anche le forti disparità territoriali e sociali. I libri sono gratuiti solo nella scuola primaria, mentre nelle secondarie le spese ricadono interamente sulle famiglie, con costi che possono superare i mille euro l’anno per studente. I tetti di spesa imposti dal Ministero risultano spesso inefficaci e facilmente aggirati, aggravando il peso economico soprattutto nelle regioni del Sud.
Un altro punto critico riguarda il mercato dell’usato, che rappresenta una risorsa importante per molte famiglie ma che viene ostacolato dalle politiche editoriali, in particolare per quanto riguarda i contenuti digitali, che non possono essere riutilizzati o ceduti. Inoltre, il rapporto evidenzia come le risorse educative aperte (OER) e le autoproduzioni didattiche siano ancora marginali, frenate da vincoli normativi e dalla mancanza di incentivi.
In conclusione, l’AGCM invita a ripensare il modello editoriale scolastico, promuovendo maggiore interoperabilità tra piattaforme, incentivando la produzione di contenuti aperti e sostenendo economicamente le famiglie e le scuole. L’obiettivo è rendere l’istruzione più accessibile, equa e al passo con le trasformazioni digitali.
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A Pechino la People’s Liberation Army mostra le sue punte di diamante
@Notizie dall'Italia e dal mondo
La parata militare svoltasi a Pechino per celebrare l’anniversario della fine della Seconda Guerra Mondiale è stata un’occasione preziosa per la Repubblica Popolare. Da una parte, la Cina ha potuto mostrare al mondo intero la solidità del blocco euroasiatico, radunando nella capitale del Celeste Impero leader
Proteste in Indonesia: crescita della rabbia sociale e solidarietà regionale
@Notizie dall'Italia e dal mondo
Nelle ultime settimane, il Paese è attraversato da una ondata di manifestazioni, generata da un mix di ingiustizie economiche e privilegi istituzionali
L'articolo Proteste in Indonesia: crescita della rabbia sociale e solidarietà regionale proviene da Pagine
ISRAELE. Smotrich vuole annettere la Cisgiordania senza i palestinesi
@Notizie dall'Italia e dal mondo
Il ministro ultranazionalista ha affermato di volere "il massimo territorio e il minimo della popolazione"
L'articolo ISRAELE. Smotrich vuole annettere pagineesteri.it/2025/09/04/med…
Lo schiaffo di Pechino
@Giornalismo e disordine informativo
articolo21.org/2025/09/lo-schi…
“Presidente Trump e’ preoccupato dell’avvicinamento di questi giorni fra Russia e Cina?”” No , io ho buoni rapporti sia con il Presidente cinese che con quello russo”. Poche volte nella storia l’inadeguatezza di un leader e’ stata cosi’ palese. L’idea, o meglio l’illusione , che la superpersonalita’ di
Ecco perché il 9 leggeremo i nomi dei giornalisti uccisi a Gaza. Prima che sia troppo tardi
@Giornalismo e disordine informativo
articolo21.org/2025/09/ecco-pe…
il giornalisticidio é stato ed é la premessa per il genocidio
L'articolo Ecco perché il 9 leggeremo
Nei voli si può anche fare a meno del Gps. Braghini spiega come
@Notizie dall'Italia e dal mondo
Il caso delle interferenze di jamming al Gps del business jet Dassault Falcon 900LX che trasportava Ursula von der Leyen in Bulgaria ha avuto immediato e ampio risalto nelle prime pagine dei quotidiani. Senza dubbio si tratta di un episodio grave per il quale si sospetta la Russia, e sarebbe dunque
OrionBelt©
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