From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-x52b.google.com (mail-ed1-x52b.google.com [IPv6:2a00:1450:4864:20::52b]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id E51DE3CB44 for ; Fri, 17 Mar 2023 18:51:10 -0400 (EDT) Received: by mail-ed1-x52b.google.com with SMTP id h8so25943077ede.8 for ; Fri, 17 Mar 2023 15:51:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=perens.com; s=google; t=1679093470; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=NeOjpq80gNLu/ErlwxqYLy5Vs4Czv+spIZeJjZb9bpc=; b=QE02RnLkYzK7nm0CnpqDbqdm2pu4v+YxJ9rwllPFm0A3RCaDebrCDdMpWjDItZGHv4 5kzNgObPTpw/4qi1t/1c0Ipfp0wA79Kg2HQeI9ZK7GR5l3vUFkh9gHZGpuMQw1e6YrTy 35WiNJslx+nDmwTd51X6H8BiqIvombiQigawk= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679093470; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=NeOjpq80gNLu/ErlwxqYLy5Vs4Czv+spIZeJjZb9bpc=; b=QNnY+TGGLSrfenxoMq5TsA2divXxjJRLK4QbiNGzdUFkFKje8pSGxIiFel4i9ZhTlx wWlWHLEfEvWFe6NdAJntwcsqKdL10NXVul01sGxMnlywxMgMOfkHPjGsA+5TfnOwPLPb dn2wuaVxjujP/2Ov44rXBItL5egWFlYvjWi/Zl7ff2tepQJwM9U/ov+mV8guUiSjM3q8 H56avWZmgaswNIXyxJ1Yq9X6VWCe7ZVRsmlqcHCTZbw/DDdujQ+HrrY1ugKRUsQwButi cokvUMiz7hlq8DdqP8l/TOVz1Ryp27bmP93Jpc1syYJ1lWrAC6BlYL+i3ki9qJRpjjf0 QXGw== X-Gm-Message-State: AO0yUKUH0WHg+S6uwrf8BoX4bBe1P96jemklqhX8tLCW5fJzARVzd+DP T42KwOa0D+Y+5GOy4bZIuDHH4mwOzHUbsYJTKlZYUA== X-Google-Smtp-Source: AK7set9Co6p+BrouFQp70LqzIyEszjqEcVT+iAAGrVZHzFQAuVp8+bP9skPA0GJvk/v0QaaAai3CLrRwzOKzp+YxdQI= X-Received: by 2002:a17:906:4d84:b0:92e:a234:110a with SMTP id s4-20020a1709064d8400b0092ea234110amr495901eju.3.1679093469746; Fri, 17 Mar 2023 15:51:09 -0700 (PDT) MIME-Version: 1.0 References: <1672786712.106922180@apps.rackspace.com> <77CCAD19-07E0-4F9E-88C1-D207CF7BF376@cable.comcast.com> <83ffc0dad19e3343e49271889369cefc@rjmcmahon.com> <3CD0B9E6-0B2A-4A70-8F53-ED0822DF77A6@gmx.de> <13DE6E53-665F-4C20-BBE2-70E685421E9D@gmx.de> <22C819FA-DDD7-4B9B-8C09-8008D4273287@gmx.de> <5e7fac51071bdbb20837e72e7eedfc7c@rjmcmahon.com> <3f45d2a0b6e46d7b2775fb801e805f93@rjmcmahon.com> <70F71290-C6CB-4D19-8A88-F0F17C0BDDA2@gmx.de> <5e0cd693c4749d128dbb48d6c1129071@rjmcmahon.com> <2ab2983d-6beb-49cb-8c35-e481cbfdc7a3@Spark> <8F56CCA3-61C4-475F-975D-99D851C6A7CF@gmx.de> <1d6c10c9a692bb3f2869fb1b40fa449a@rjmcmahon.com> <005d1e7e3e1d19bce308436e46a3ec5e@rjmcmahon.com> In-Reply-To: <005d1e7e3e1d19bce308436e46a3ec5e@rjmcmahon.com> From: Bruce Perens Date: Fri, 17 Mar 2023 15:50:57 -0700 Message-ID: To: rjmcmahon Cc: Sebastian Moeller , libreqos , Dave Taht via Starlink , Rpm , bloat Content-Type: multipart/alternative; boundary="000000000000cf2f6705f720695b" Subject: Re: [Rpm] [Starlink] On FiWi X-BeenThere: rpm@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: revolutions per minute - a new metric for measuring responsiveness List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 17 Mar 2023 22:51:11 -0000 --000000000000cf2f6705f720695b Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Fri, Mar 17, 2023 at 1:57=E2=80=AFPM rjmcmahon = wrote: > I'm curious as to why the detectors have to be replaced every 10 years. Dust, grease from cooking oil vapors, insects, mold, etc. accumulate, and it's so expensive to clean those little sensors, and there is so much liability associated with them, that it's cheaper to replace the head every 10 years. Electrolytic capacitors have a limited lifetime and that is also a good reason to replace the device. The basic sensor architecture is photoelectric, the older ones used an americium pelllet that detected gas ionization which was changed by the presence of smoke. The half-life on the americium ones is at least 400 years (there is more than one isotope, that's the shortest-life one). --000000000000cf2f6705f720695b Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


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On Fri, Mar 17, 2023 at 1:57=E2=80=AF= PM rjmcmahon <rjmcmahon@rjmcm= ahon.com> wrote:
I'm curious as to why the detectors have to be replaced every 1= 0 years.

Dust, grease from cooking oil vapo= rs, insects, mold, etc. accumulate, and it's so expensive to clean thos= e little sensors, and there is so much liability associated with them, that= it's cheaper to replace=C2=A0the head every 10 years. Electrolytic cap= acitors have a limited lifetime and that is also a good reason to replace t= he device.

The basic sensor architecture is photoe= lectric, the older ones used an americium pelllet=C2=A0that detected gas io= nization which was changed by the presence of smoke. The half-life on the a= mericium ones is at least 400 years (there is more than one isotope, that&#= 39;s the shortest-life one).
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