From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bobcat.rjmcmahon.com (bobcat.rjmcmahon.com [45.33.58.123]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 30A303CB38; Sat, 18 Mar 2023 14:18:26 -0400 (EDT) Received: from mail.rjmcmahon.com (bobcat.rjmcmahon.com [45.33.58.123]) by bobcat.rjmcmahon.com (Postfix) with ESMTPA id 39EC71EEE8; Sat, 18 Mar 2023 11:18:25 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 bobcat.rjmcmahon.com 39EC71EEE8 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rjmcmahon.com; s=bobcat; t=1679163505; bh=tjP8dkWn9lX7DBXnwi8g6ztGhiDo4XEgy5CPQwhPIwQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=FRVcRLeXXsRA+Bo2SWtDb+/yI961U+i+w6lgrlrrI/C473HoQD+3jilPVvYDIGDGL US4v8gp6Gi+H3CCjitUdrvEMzF3odo4e0OVsjSSXC9pnH8dqWxLYeJ0iZts2oifoD8 sk1subCHhYyMK5gtqNHnr1M7uJkYwGe0V+0KFSdg= MIME-Version: 1.0 Date: Sat, 18 Mar 2023 11:18:25 -0700 From: rjmcmahon To: Bruce Perens Cc: Sebastian Moeller , libreqos , Dave Taht via Starlink , Rpm , bloat In-Reply-To: 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> Message-ID: X-Sender: rjmcmahon@rjmcmahon.com Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Subject: Re: [Bloat] [Starlink] [Rpm] On FiWi X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 18 Mar 2023 18:18:26 -0000 >> 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). Thanks for this. That makes sense. I do think the FiWi transceivers & sensors need to be pluggable & detect failures, particularly early on due to infant mortality. "Infant mortality is a special equipment failure mode that shows the probability of failure being highest when the equipment is first started, but reduces as time goes on. Eventually, the probability of failure levels off after time." https://www.upkeep.com/blog/infant-mortality-equipment-failure#:~:text=Infant%20mortality%20is%20a%20special,failure%20levels%20off%20after%20time. Also curious about thermal imaging inside a building - what sensor tech to use and at what cost? The Bronx fire occurred because poor people in public housing don't have access to electric heat pumps & used a space heater instead. It's very sad we as a society do this, i.e. make sure rich people can drive Teslas with heat pumps but only provide the worst type of heating to children from families that aren't so fortunate. https://www.cnn.com/2022/01/10/us/nyc-bronx-apartment-fire-monday/index.html "A malfunctioning electric space heater in a bedroom was the source of an apartment building fire Sunday in the Bronx that killed 17 people, including 8 children, making it one of the worst fires in the city’s history, New York Mayor Eric Adams said Monday." Bob