Instrument accurately measures weld angle and offset

Weld angle is measured to the nearest arc minute and offset to one thousandth of an inch by an instrument designed to use a reference plane at two locations on a test coupon. A special table for computation has been prepared for use with the instrument

The Non-Market Benefits of Nature: What Should Be Counted in Green GDP?

Green gross domestic product (green GDP) is meant to account for nature’s value on an equal footing with the market economy. Several problems bedevil green GDP, however. One is that nature does not come prepackaged in units like cars, houses, and bread. Even worse, green GDP requires measurement of the benefits arising from public goods provided by nature for which there are no market indicators of value. So what should green GDP count? That is the subject of this paper. Ecological and economic theory are used to describe what should be counted—and what should not—if green GDP is to account for the nonmarket benefits of nature.green GDP, environmental accounting, ecosystem services, index theory, nonmarket valuation

Infrared upconversion for astronomy

The basic theory of upconversion is presented, along with a brief historical summary of upconversion techniques. Upconverters were used in astronomical studies, but have met with only modest success. Upconversion will become a useful detection method for astronomy only if substantial but perhaps forseeable, improvements can be realized

Introduction to Library Trends 55 (3) Winter 2007: Libraries in Times of War, Revolution and Social Change

published or submitted for publicatio

An introduction to ghost imaging: quantum and classical

Ghost imaging has been a subject of interest to the quantum optics community for the past 20 years. Initially seen as manifestation of quantum spookiness, it is now recognized as being implementable in both single- and many-photon number regimes. Beyond its scientific curiosity, it is now feeding novel imaging modalities potentially offering performance attributes that traditional approaches cannot match

Flexible high speed codec

The project's objective is to develop an advanced high speed coding technology that provides substantial coding gains with limited bandwidth expansion for several common modulation types. The resulting technique is applicable to several continuous and burst communication environments. Decoding provides a significant gain with hard decisions alone and can utilize soft decision information when available from the demodulator to increase the coding gain. The hard decision codec will be implemented using a single application specific integrated circuit (ASIC) chip. It will be capable of coding and decoding as well as some formatting and synchronization functions at data rates up to 300 megabits per second (Mb/s). Code rate is a function of the block length and can vary from 7/8 to 15/16. Length of coded bursts can be any multiple of 32 that is greater than or equal to 256 bits. Coding may be switched in or out on a burst by burst basis with no change in the throughput delay. Reliability information in the form of 3-bit (8-level) soft decisions, can be exploited using applique circuitry around the hard decision codec. This applique circuitry will be discrete logic in the present contract. However, ease of transition to LSI is one of the design guidelines. Discussed here is the selected coding technique. Its application to some communication systems is described. Performance with 4, 8, and 16-ary Phase Shift Keying (PSK) modulation is also presented

Positive ion temperatures above the F-layer maximum

Positive ion temperatures above F layer maximum from Ariel I satellite ion mass analyze