Diofantos: Physical Sciences & Mathematics

30/03/2025

Συνδεσμολογιες συσσωρευτων (μπαταριών) αυτοκινήτων.

Παρατηρειστε ότι η ισχύς εξόδου και στις 3εις συνδεσμολογιες είναι θεωρητικά (οι αγωγοί θεωρούνται ιδανικοί) ίδια.

17/03/2025

Νέα εξήγηση του φαινομένου της πτήσης των αεροσκαφών. Πολύ ενδιαφέρον video για Φυσικούς, Μηχανικούς, Πιλότους και όλους όσους αγαπούν την εφαρμοσμένη Φυσική.

Most people have heard that airplane wings generate lift because air moves faster over the top, creating lower pressure due to Bernoulli’s principle. While t...

19/05/2023

Το τελευταίο μάθημα Γραμμικής Άλγεβρας του Εξαιρετικού Καθηγητή Gilbert Stang στο MIT, πριν αποχωρήσει στα 88 του έτη ως συνταξιούχος.

What more do you need to know? 😉

10/02/2023

https://www.facebook.com/100063724982888/posts/626798559454305/?sfnsn=mo

11/12/2022

Nicola Tesla vs Albert Einstein

03/12/2022

Καταπληκτικό κείμενο από έναν αξιοθαυμαστο αλλά και εκκεντρικό Άνθρωπο και Επιστήμονα. Αξίζει να το διαβάσετε.

https://www.facebook.com/100063724982888/posts/566535505480611/?sfnsn=mo

27/11/2022

Συμπληρώνω ότι τα βιβλία του είναι καταπληκτικά και πολύ ανώτερα σε περιεχόμενο και επεξηγήσεις από τα σύγχρονα του είδους.

Ποιου είδους?

Της Εφαρμοσμένης Ηλεκτροδυναμικης!

https://www.facebook.com/100063724982888/posts/562698409197654/?sfnsn=mo

Electrical Genius: C. P. Steinmetz

Charles Proteus Steinmetz was a German-American mathematician and electrical engineer. He was a very short man with a hunchback, but that didn't prevent him from becoming one of the more significant contributors to the knowledge of electricity. Steinmetz' mathematical work with regard to alternating currents helped revolutionize the electric power industry in the United States with his ground-breaking discoveries in the understanding of hysteresis (a lag between input and output in a system upon a change in direction). This discovery enabled engineers to design far better AC systems for use in commercial applications.

Steinmetz moved to the U.S. in 1889 after fleeing imprisonment in Germany for his socialistic political views. He immediately became acquainted with engineers such as Elihu Thomson, Mihajlo Pupin and Thomas Edison (all rivals of Nikola Tesla and the Westinghouse Co.). Although Steinmetz was new to the political differences in the commercial development of power distribution (AC vs. DC), it wouldn't take long before his new friends pressured him into joining their side against the opposition.

But before he teamed up with Thomson-Houston Electric (which later merged with Edison Electric to form General Electric), Steinmetz pointed out certain flaws in their understanding of polyphase AC generators. During a meeting of the American Institute of Electrical Engineers (Dec.16, 1891), a paper written by Pupin on polyphase AC generators was discussed. One of Pupin's arguments was that Ferraris and Dolivio-Dobrowolosky created the first polyphase motors. This was key to GE engineers because this allowed them to combat Westinghouse and Tesla's AC patents. Steinmetz, in turn, was quick to call out the mistakes. In the discussion, Steinmetz says:

"Ferraris built only a little toy, and his magnetic circuits, so far as I know, were completed in air, not in iron…

"This three-phase current system has been brought up the last time as something entirely new. I cannot agree with that in the least. For already in the old Tesla motor the three phases of current, only that in the three wires that go out from the central station the three currents have not a difference of phase of exactly 120 degrees, but two have a difference of 90 degrees, and either one of these two currents has with the third a difference of phase of 135 degrees. But if now the "Allgemeine Electricitats Gesellschaft" transmits currents of less than 120 degrees difference of phase-well, then the Dobrowolsky system comes back exactly to the old three-wire system of Tesla, only that the motor is certainly built somewhat differently. But that does not matter. Mechanically, the motor is undoubtedly improved, for there are several years' time between the old Tesla three wire motor and the new German three phaser. Whether the latter shows any improvements in its principles, is a question which is anything but beyond doubt.

"But in the new Dolivo von Dobrowolsky system of electric distribution, I really cannot see anything new but the mechanical construction of motors and generators. That it became so famous is, I think, entirely due to the success of the grand transmission of power over such an enormous distance as 116 miles, which cast a halo around everything that was used with this transmission, and so made the rotary motor famous; but, in reality, I think ordinary synchronous motors might just as well have been used, and would have worked just as successfully, so that the choice of the particular motor had nothing to do with the success of the power transmission."

Unfortunately for Steinmetz, these refutations would later come back to haunt him. Tesla's patents would gain priority over Ferraris and Dolivio-Dobrowolosky. Thomson would succumb to hiring a janitor to steal AC blueprints from the Westinghouse Co. so his company could bypass Tesla’s patents and build their own AC system. Pupin continued to discredit Tesla as the true inventor of the polypase motor in lectures and in his Pulitzer Prize winning autobiography—even though the inventors he gave credit to admitted they got their idea from Tesla. Steinmetz' genius was recognized, and he was hired to helped Thomson and GE bypass Tesla’s patents. Later he intentionally omitted any reference to Tesla in his famous writings on AC phenomena. Each of the afore-mentioned engineers made a name for themselves, and their deplore of Tesla has unquestionably contributed to Tesla being excluded from history and science books of today.

24/11/2022

https://www.astronomynewreporter.com/2022/09/danish-physicist-lene-hau-was-able-to.html?m=1

The speed of light is a universal physical constant that is important in many aspects of physics. Light travels at a continuous and finite...

14/11/2022

https://www.facebook.com/100063724982888/posts/549505797183582/?sfnsn=mo

3 Main Misconceptions About Nikola Tesla

1. Did Nikola Tesla invent Alternating Current (AC)?

No, Nikola Tesla did not invent AC. It is a common mistake made by both critics and followers of Nikola Tesla that Tesla invented, or discovered AC. This page has never claimed such a thing. It is well known that Hippolyte Pixii was the first to discover AC in 1832. Pixii was an instrument maker from Paris who built an early form of an alternating current electrical generator (based on the principle of electromagnetic induction discovered by Michael Faraday), and he started a new industry in power transmission. Without going into too much historical detail, Tesla was not the first to discover or invent an AC motor, but he was the first inventor to discover the rotating magnetic field. This discovery revolutionized the transmission of power that is still utilized today, allowing AC to be more efficient in that it eliminated the commutator on older AC systems which caused friction and made for much difficulties in productivity. With Tesla’s discovery, the commutator was discarded, and the obstacles of friction were gone. This allowed AC to be able to compete with the opposing system known as Direct Current (DC), and made the system an even better value in commercial applications. Some may argue that others developed the rotating magnetic field before Tesla, but these are all false claims. Such claims were even made by the opposition of Tesla’s system during his time, but all failed to bring forth sufficient evidence and subsequently lost in court battles. One example was the claim that Galileo Ferraris discovered the rotating magnetic field before Tesla. Ferraris wrote a pamphlet in 1888, which appeared seven months after Tesla’s filed patent. However, his publication only described a split-phase motor, and after the courts analyzed and compared Ferraris’ system to Tesla's polyphase system, Tesla was given priority. Even if one says Ferraris discovered it prior to his publication, it could be said that Tesla discovered the rotating magnetic field in 1882 (3 years before Ferraris supposed discovery), and produced motors that same year. Ultimately, it all comes down the evidence, and why Tesla was awarded priority over everyone, including Schallenberger, Cabanellas, Brown and Dobrowolsky. Therefore, Tesla was indeed the pioneer who revolutionized the power system we globally still rely on today.

2. Did Tesla really invent radio?

Yes. Nikola Tesla is the true father of radio. Even if the U.S. Supreme Court didn’t rule that Guglielmo Marconi was using Tesla’s patents, it’s still an undisputed fact that Tesla created the radio as we know it today. As early as 1891, Nikola Tesla was giving lectures and demonstrations on the transmission of wireless energy preceding J.C Bose (1895), Alexander Popov (1895) and Marconi (1895) by three years. Tesla developed what is known as the “Tesla Coil”, which was used in all wireless transmission up until the late 1920s. However, Marconi has always been the main person who people claim invented radio - this is simply not the case. After Marconi’s system was examined, it was easily found that he was using Tesla’s four-tuned circuits that Tesla had previously patented. This confirms Tesla holds the rightful title as being considered the father of radio.

3. Did Nikola Tesla promote free energy?

No. Tesla did not proselytize anything about free energy. This has been one of the toughest conspiracies to substantiate in that most of Tesla's followers believe that he wanted to provide “free energy" to the world. Yes, Tesla wanted to bring the world cheaper, and clean energy, but he never once said “free energy.” He has, however made statements referring to the notion of unlimited energy from the sun (and other suns in the galaxy from cosmic rays), but never any claims regarding zero point energy or procuring energy free of expense. Perhaps if his world wireless system had successfully been implemented, power costs would have been much less expensive and power could have been obtained at any point on earth; however; consumers would still have to subscribe to the provider and pay fees. Energy is not free, nor ever is likely to be.

24/10/2022

"I have produced electrical discharges the actual path of which, from end to end, was probably more than one hundred feet long; but it would not be difficult to reach lengths one hundred times as great. I have produced electrical movements occurring at the rate of approximately one hundred thousand horse-power, but rates of one, five, or ten million horse-power are easily practicable. In these experiments effects were developed incomparably greater than any ever produced by human agencies, and yet these results are but an embryo of what is to be.“

— Nikola Tesla

“The Problem of Increasing Human Energy.” Century Illustrated Magazine, June 1900.

30/09/2022

Πεδιακη θεώρηση μετάδοσης και κατανάλωσης της ηλεκτρικής ενέργειας σε γραμμή μεταφοράς:

Το Poynting vector ως γνωστόν δείχνει την κατεύθυνση ροής της ηλεκτρικής ισχύος. Έχει δε, διαστάσεις έντασης και η έκφραση του δίνεται στο κάτω μέρος της εικόνας.
Το Poynting vector που αφορά στην μεταδιδομενη ισχύ είναι παράλληλο προς τον καλό αγωγό και έξω από αυτόν!

Παρατηρειστε ότι επί του αγωγού υπάρχει επιφανειακό φορτίο (κι άρα ακτινικο ηλεκτρικό πεδίο κυλινδρικής κατά προσέγγιση συμμετρίας) τόσο στον αγωγό φάσης(άνω αγωγός στην εικόνα) όσο και στον ουδέτερο (κάτω αγωγός στην εικόνα).

Αυτό το επιφανειακό φορτίο καθορίζεται από το δυναμικό φάσης και ουδέτερου (που είναι συνήθως γειωμενος). Η τάση στις γραμμές μεταφοράς υψηλής τάσης πέφτει πολύ αργά κατά μήκος της γραμμής που είναι πολύ καλός αγωγός. Γι αυτό εξάλλου υπάρχουν οι υποσταθμοι αναβιβασης τάσης στη διαδρομή από την πηγή προς την κατανάλωση.

Το μαγνητικό πεδίο (πράσινοι βρόχοι) στροβιλιζει κανονικά γύρω από την πηγή του που είναι το ρεύμα(πυκνότητα ρεύματος J). Το ρεύμα προκύπτει λόγω της διαφοράς δυναμικού μεταξύ φάσης και ουδέτερου: E=-δV/δx και J=σE, όπου Ε είναι το αξονικο ηλεκτρικό πεδίο!

Το Poynting vector που αφορά στην καταναλισκομενη ισχύ (φαινόμενο Joule) εισέρχεται στον αγωγό και είναι κάθετο σε αυτόν!

Στο καθαρό ωμικο φορτίο (αντίσταση στα δεξιά της εικόνας) έχουμε μόνο εισερχόμενα Poynting vectors από όλο το κύκλωμα (φάση και ουδέτερο), ενώ κατά μήκος του καλού αγωγού(φάσης, η, ουδέτερου) έχουμε 2 συνιστώσες: Το παράλληλο και το κάθετο στον αγωγό!