The Material Politics of Finance: The Ticker Tape and the London Stock Exchange, 1860s–1890s

When the ticker tape was first invented in the 1860s, it promised a revolution in financial markets. Pricing information was now no longer solely the domain of the trading floor but was relayed continuously and simultaneously to ticker tapes long distances away from the stock exchange. Both nineteenth-century financiers, and the modern scholars who study them, have been enamored with the ticker tape and how it changed the way financial markets were perceived and experienced. However, a focus on how nineteenth-century financiers read and responded to the ticker tape has missed the real reordering of power that the ticker helped usher in. This article argues that between the 1860s and 1890s the London Stock Exchange and the Exchange Telegraph Company powerfully centralized their control over the distribution and transmission of financial information through the mundane infrastructures that underpinned the ticker tape system. Seeming technicalities, like the placement of batteries, the construction of electrical circuits, and the laying of wires and cables, were leveraged by these institutions to create a ticker tape system that distributed financial information unequally to financiers and investors throughout Britain. By the end of the nineteenth century, social and political questions about who should have access to financial information and markets, and on what terms, became helplessly intertwined with the mundane technicalities of the material infrastructures of modern finance.

The GridKa Tape System: status and outlook

Tape storage is still a cost effective way to keep large amounts of data over a long period of time and it is expected that this will continue in the future. The GridKa tape environment is a complex system of many hardware components and software layers. Configuring this system for optimal performance for all use cases is a non-trivial task and requires a lot of experience. We present the current status of the GridKa tape environment, report on recent upgrades and improvements and plans to further develop and enhance the system, especially with regard to the future requirements of the HEP experiments and their large data centers. The short-term planning mainly includes the transition from TSM to HPSS as the backend and the effects on the connection of dCache and xrootd. Recent changes of the vendor situation of certain tape technologies require a precise analysis of the impact and eventual adaptation of the mid-term planning, in particular with respect to scalability challenge that comes with HL-LHC on the horizon.

Evaluation of a Lead-Free Ultra Low Temperature Co-Fire Ceramic (ULTCC) Tape Designed for Lamination on Aluminum Substrates and a Compatible Co-Fireable Silver Conductor

Light-emitting diodes (LEDs) are the product of choice for many commercial and industrial lighting applications. Due to increasing power densities, alternative mounting solutions are being evaluated in order to achieve the lowest junction temperatures and lowest thermal resistances. Previous papers have explored the benefits of using a thick film system as opposed to a traditional Metal Core Printed Circuit Board (MCPCB). The advantage of being able to directly insulate a heat sink eliminates additional MCPCB layers and mechanical attachment that can decrease the thermal conductivity of the module and increase cost. Lower thermal resistance results in higher performing LED modules at a lower cost and a longer lifetime. A process has been developed and evaluated where an ultra-low temperature co-fired ceramic (ULTCC) tape will be laminsated directly on to an aluminum heat sink in order to electrically isolate the substrate. The green tape will then have a silver conductor applied to it and fired in one step. Using a tape system as opposed to an ink system creates many advantages. The tape system allows for processing in cavities, which is beneficial for recessed lighting and three-dimensional substrates. The co-firing silver conductor reduces the number of firing steps, leading to less dimensional variation of the heat sink and lower processing costs. This paper will discuss the material solutions, processing requirements, and reliability data for a completely co-fired ULTCC system on aluminum.

Miniature Lowpass Filters in Low Loss 9k7 LTCC

DuPont 9k7 low temperature cofired ceramic (LTCC) is a low loss, or high quality factor Q, tape system targeting at radio frequency (RF) applications. This paper reports the effect of a critical process parameter, heating rate, on the densification and dielectric properties of the 9k7 LTCC. The role of competing densification and crystallization during the sintering of 9k7 is discussed. The high Q of DuPont 9K7 can be used to improve RF system performance, for example a better receiver noise figure, by designing embedded passive RF components such as inductors, capacitors and filters. Miniaturized multilayer low pass filters (LPF) with a wide stopband were fabricated to showcase the technology.