Blue birds huddling together for warmth
pic.twitter.com/t0SEG4CZhs— Science girl (@gunsnrosesgirl3) December 27, 2024
Topology of Continuous Availability for LED Lighting Systems
Giuseppe Parise – Marco Allegri
Luigi Parise
Raffaele Pennacchia – Fabrizio Regoli
Giorgio Vasselli
Abstract: Lighting systems with a big number of luminaires in large halls are a case of distributed loads that need topologies with modularity, whenever possible to ensure a uniform distribution of the supplying circuits, an easier installation, management, and maintenance. The light emitting diode (LED) luminaires give a great impact on the system operation due to their auxiliary series devices and to the high inrush currents of the ac-dc switching power supplies. This article proposes a topology to design LED lighting systems, configured in a modular scheme of a main ac distribution and a branch dc distribution supplying luminaires clusters. Each cluster is provided as a “double-dual corded” equipment with double power supply and double control type, digital, and analogic. The suggested topology aims to make available a system that allows overcoming fault situations by design and permits maintenance activities limiting and recovering degradation conditions. In this way, the lighting system of special locations, for which there is the willingness-to-accept greater financial costs against loss service risks, can satisfy the requirement of continuous availability system. To provide more details on the proposed design criteria this article describes, as case study, the lighting system of a parliamentary hall with one thousands of luminaires.
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print(“Illumination”)@beatricedegraaf @UniofOxford pic.twitter.com/DBIvns5k4K— Standards Michigan (@StandardsMich) February 17, 2022
The National Electrical Contractors Association best practice catalog features a suite of titles (National Electrical Installation Standards to meet the intent of the National Electrical Code (NEC); particularly where the NEC asserts that an installation be constructed in a “neat and workmanlike manner”. As anyone who has had to reckon with the subjectivity of the local electrical inspector knows, the determination of “neat and workmanlike” can be mighty subjective. The NECA documents are used by construction owners, specifiers, contractors and electricians to clearly illustrate the performance and workmanship standards essential for different types of electrical construction. Because the NEC is intended to be primarily a wiring safety standard, the NEIS suite is referenced throughout the National Electrical Code. Electrical shop foremen and front line electricians take note.
NECA Standards and Publication Development Home Page
One of the NECA products that may be of interest to facility managers and risk management units in the education industry this time of year is NECA 202-2013 Standard for Installing and Maintaining Industrial Heat Tracing Systems. About half of the United States deals with snow and ice half the year.
NECA 202 details procedures for the installation, testing, and documentation of electrical freeze protection and process heat tracing systems. Heat tracing cable types covered by this publication include: self-regulating, constant wattage, and zone heating cables and mineral insulated heating cables. 2 is approved as an American National Standard. The 2013 edition is the current edition and will likely need revisiting/revision/reaffirmation as an American national standard soon.
The technical literature that keeps pipes breaking and roofs failing is complicated space. A common conundrum in the construction industry is which discipline (architectural, mechanical or electrical) should specify application of this technology; especially in value-engineering negotiations when each discipline is trying to reduce its unit costs. Control and communication system add another layer of complexity. Several consensus standards occupy this technology; cross referencing one another and leaving gaps
ASCE 7-10 Snow Load Provisions
UL 515 Standard for Electrical Resistance Trace Heating for Commercial Applications
IEC 62395 Electrical resistance trace heating systems for industrial and commercial applications
National Electrical Code Article 427
There are codes and standards developed by ASTM International, the International Code Council and ASHRAE International that set the standard of care for pipe insulation for energy conservation purposes but we will deal with the interdependence of standard of care set by those documents in a separate post. Organizations such as FM Global typically derive their customer recommendations from consensus standards developers.
Because heat tracing is a cross-disciplinary technology we maintain it on the standing agenda of several colloquia: Power, Water, Bucolia, Snow & Ice and Mechanical See our CALENDAR for the next meeting; open to everyone. You may obtain an electronic copy of this standard from [email protected]. Communicate directly with Aga Golriz, (301) 215-4549, [email protected].
Participation by the public in reviewing other titles in the NEIS bibliography is welcomed and begins at the page linked below:
Issue: [19-24]
Category: Architectural, Electrical, Facility Management, Mechanical, Risk Management,
Colleagues: Eric Albert, Mike Anthony, Jack Janveja, Richard Robben, Larry Spielvogel
More
RESEARCHGATE: HEAT-TRACING OF PIPING SYSTEMS TYPES OF HEAT-TRACING SYSTEMS
With some 36 million square feet under management — and one of the largest campuses in the United States exposed to extreme low temperatures — building industry professionals at the University of Michigan have some experience managing the competing requirements of safety and economy in heat tracing technology.
In the pursuit of Knowledge,
every day something is added.
In the practice of the Way,
every day something is dropped.
Less and less do you need to force things,
until finally you arrive at non-action.
When nothing is done,
nothing is left undone.
— Lao Tzu
United States Department of Agriculture | Turkey Standards Country Report
Sufganiyot (plural), sufganiyah (singular); are a type of deep-fried doughnut that is traditionally eaten by Jewish people during Hanukkah, along with other fried foods, to commemorate the miracle of the oil in the Temple. They are typically round and filled with jelly or other sweet fillings, and they are often dusted with powdered sugar. Sufganiyot are deep-fried until they are golden brown and have a light, fluffy texture.
The practice of eating fried foods during Hanukkah is a symbolic way of celebrating the miracle of the oil, where a small amount of oil miraculously lasted for eight days in the rededication of the Temple in Jerusalem.
Time has no beginnings and history has no bounds. The way we understand the past is always changing:
History never says “Goodbye”.
History always says “See you later”
“When Herodotus composed his great work,” Richard Cohen writes at the start of Making History: The Storytellers Who Shaped the Past, “people named it The Histories, but scholars have pointed out that the word means more accurately ‘inquiries’ or ‘researches.’ Calling it The Histories dilutes its originality.
I want to make a larger claim about those who have shaped the way we view our past—actually, who have given us our past. I believe that the wandering Greek’s investigations brought into play, 2,500 years ago, a special kind of inquiry—one that encompasses geography, ethnography, philology, genealogy, sociology, biography, anthropology, psychology, imaginative re-creation (as in the arts), and many other kinds of knowledge, too. The person who exhibits this wide-ranging curiosity should rejoice in the title: historian.”
Soundcloud Podcast: The World in Time
New update alert! The 2022 update to the Trademark Assignment Dataset is now available online. Find 1.29 million trademark assignments, involving 2.28 million unique trademark properties issued by the USPTO between March 1952 and January 2023: https://t.co/njrDAbSpwB pic.twitter.com/GkAXrHoQ9T
— USPTO (@uspto) July 13, 2023
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