An investigation of bulk recycling planning for an electronics recycling facility receiving industrial returns versus residential returns

Since most end-of-life electronics equipment contain hazardous materials such as lead solder alloys or lead-impregnated glass, it is important to divert them from landfills. For end-of-life products that are not repairable and do not contain reusable parts, bulk recycling is an alternative to recover base materials. In this paper, we contrast production and recycling planning and distribution decisions, activities, and costs. We reveal that while a traditional production facility connects suppliers and customers, a recycling facility connects both "input" and "output" customers. As a result, decisions in short-term bulk recycling planning include what products to accept, what products to process and reprocess, and what products to carry in inventory. Many recyclers set prices to receive "input" based on experience. For various prices to receive "input", we use a new analytical model to investigate the sensitivity of the short-term bulk recycling planning decisions in products from two different sources: industrial returns versus residential returns. The results of the case study show that different decisions are recommended for the industrial returns versus the residential returns when the total quantity of the incoming products is equal.     

Correlation properties of ocean altimeter returns

The correlation properties of altimeter returns are useful in the optimal design of altimeter systems. They are also necessary for implementing maximum likelihood estimation algorithms for altimeter waveform parameter estimation. The authors derive a simple expression for the bin-to-bin and pulse-to-pulse correlation of altimeter waveforms. This expression is a triple convolution of the specular point probability density function, a product of altimeter point target responses, and a generalized surface impulse response. This result is analogous to the usual expression for the mean altimeter waveform. The authors compare these theoretical predictions against real data, using measurements from the Skylab and Geosat altimeters. Finally, they present a simple application of the results to altimeter system design     

Spectrum analysis of ionospheric radar returns

A digital method of extracting ionospheric information from the Doppler broadening of radar signals is presented. 1 bit correlation, used by Weinreb in radioastronomy, is applied to measuring autocorrelation functions of ionospheric incoherent scatter returns. Calculated correlation functions are fitted to the observations to derive electron and ion temperatures.     

Recipe for recycling

Across-the-board recyclers can keep discarded electronic products out of landfills by identifying and extracting component parts for resale and materials for reprocessing. The complete recycling of electrical and electronic equipment will in the future probably be handled by independent recyclers who become specialized in understanding the varieties of discarded equipment. They will plan the logistics of recovering any assemblies, components, and materials of value, and will develop the technologies necessary to extract them in a way that is economical and environmentally sound. The actual recycling activities will also probably take place in central locations, if for no other reason than the substantial costs of moving material and equipment. The integrated recycling approach ranks the means of disposal in order of feasibility: refurbishing; or equipment brokering, possibly to underdeveloped countries; component recovery; or full material recycling     

State-of-the-art recycling plant

Consumer electronics giant Matsushita has opened up the METEC (Matsushita Eco Technology Center Company) recycling plant in Japan. The center, the largest of its kind in Japan, opened in 2001 in response to Japan's new law for recycling specific kinds of home appliances. The Hyogo plant recycles all four appliances specified in the law: television sets, refrigerators, air conditioners, and washing machines. For the most part, it recycles these products in kind-that is, crushed glass from TV tubes is used to make new TV tubes; reprocessed plastic from refrigerators is used to make parts for new refrigerators; metals from air conditioner compressors are used to make new compressors; and polypropylene from washing machines is extracted from the other plastics and used to make the bases of new washing machines.     

Modeling lidar returns from forest canopies

Remote sensing techniques that utilize light detection and ranging (lidar) provide unique data on canopy geometry and subcanopy topography. This type of information will lead to improved understanding of important structures and processes of Earth's vegetation cover. To understand the relation between canopy structure and the lidar return waveform, a three-dimensional (3D) model was developed and implemented. Detailed field measurements and forest growth model simulations of forest stands were used to parameterize this vegetation lidar waveform model. In the model, the crown shape of trees determines the vertical distribution of plant material and the corresponding lidar waveforms. Preliminary comparisons of averaged waveforms from an airborne lidar and model simulations shows that the shape of the measured waveform was more similar to simulations using an ellipsoid or hemi-ellipsoid shape. The observed slower decay of the airborne lidar waveforms than the simulated waveforms may indicate the existence of the understories and may also suggest that higher order scattering from the upper canopy may contribute to the lidar signals. The lidar waveforms from stands simulated from a forest growth model show the dependence of the waveform on stand structure.     

Target discrimination using multiple-frequency amplitude returns

A technique for radar target discrimination using multiple-frequency scattering amplitude data is investigated. Based on the concept of natural resonance frequencies, the technique is aspect-angle independent. This is achieved through simple signal processing, thus providing nearly real-time operation. The radar cross sections (RCS) of spheroids are calculated numerically to simulate the received radar returns for discriminating different spheroids and wires in the resonance frequency region. The simulation also takes into account the effect of noise which appears in practical measurement     

Pebble-bed design returns [nuclear reactor]

Chicago's Exelon Corp., the largest operator of nuclear plants in the United States, and three international partners will make a decision that could jump-start a nuclear revival. Led by South Africa's state utility Eskom, of Johannesburg, the four will decide whether to continue investing in the pebble-bed modular reactor technology. The concept originated in West Germany in the 1960s and 1970s, and is now experiencing a startling revival. Specifically, the four companies will decide whether to fund a full-scale prototype pebble-bed reactor in South Africa, at Koeberg, near Cape Town. If the South African pebble-bed project moves ahead, Exelon will seek design certification from the US Nuclear Regulatory Commission (NRC), Rockville, Md., so that the technology could be sold as a standardized, off-the-shelf design, like the three advanced light-water designs already precertified by the NRC. Exelon hopes to submit an application for a pebble-bed modular-reactor license to the commission in late 2002, start construction around mid-2005, and begin operations for the first unit about three years later. The pebble-bed concept uses a helium coolant and a graphite moderator. The fuel-uranium dioxide enriched in ²³⁵ U to 8-10%-consists of particles coated with two layers of carbon and one of silicon carbide, embedded in a carbon matrix, which act as the principal barrier against radioactive releases. The paper describes the operating features of this technology, the safety aspects and commercial prospects     

Experimental discrimination of wire stick targets usingmultiple-frequency amplitude returns

An experimental radar target discrimination algorithm using multiple-frequency scattering amplitude without phase data is investigated. The technique is based on the concept of natural resonance frequencies, which are aspect-independent so that prior information of the aspect angle is not necessary. The radar cross sections of two wire stick models are measured at different aspect angles for distinguishing these two similar targets in the resonance frequency range. By the one-number method, the risk values of different test targets are calculated and compared using the minimum-risk strategy. The results show that the discrimination algorithm works well under experimental conditions if the natural resonance frequencies of different targets are unlike enough. The effect of noise is also investigated     

Field returns, a source of natural failure mechanisms

Reliability investigations and product qualifications are typically built on a set of “standard” aging methods which are designed to extract degradation that can be statistically analyzed in order to predict lifetimes. This study is intended to reveal information about what actually happens to devices during use by the customer as determined by failure analysis. This information is provided as an account of experiences with supplier-customer relationships It is intended to describe expectations (from the supplier viewpoint) and to guide aging and qualification methodologies towards meeting those expectations. Comparisons to accelerated aging results are discussed. This work was initiated to provide a modern update to a similar paper entitled: “GaAs IC Reliability Returns: A Story of Abuse”. The original data was presented at the 1992 GaAs REL Workshop on October 4, 1992 in Miami Beach, Florida [Roesch Bill, Rubalcava AL, Winters RA. GaAs IC reliability returns: a story of abuse. In: GaAs REL Workshop, October 4, 1992, Miami Beach, Florida. p. 30-4. [1]].     

以物资循环再利用构筑成本领先

介绍了国内外物资循环再利用的开展情况,分析了该项工作的发展趋势、现实意义和必要性,重点提出了关于开展物资循环再利用工作的几点建议.     

空闲机时发布中安全问题的讨论

Internet由于其巨大的接入量，成为发布空闲机时的理想环境。开发通用的空闲机时发布系统，是解决使用空闲机时不便，发布机时难的方法，对于通用系统，安全问题是一个关键性问题。针对这一情况，本文分析了可能存在的安全问题，即认证、授权、记账和保护结果正确四方面的问题。结合我们开发的通用空闲机时发布系统WebCRP，提出了处理这些安全问题的方法。分析表明这些方法可有效地解决相应的安全问题。     

Adaptive double recycling folded cascode amplifier

Analog Integrated Circuits and Signal Processing - A new structure for improving the performance of recycling folded cascode (RFC) operational transconductance amplifier (OTA) is presented. The...     

Double recycling technique for folded-cascode OTA

Presented is a double-recycling folded cascode (DRFC) operational transconductance amplifier (OTA), demonstrating another phase of significant performance enhancement over the existing folded cascode, recycling folded cascode and improved recycling folded cascode counterparts. Theoretical treatments and computer simulations under the same 65 nm CMOS technology justify fairly the merits of the proposed DRFC OTA.     

High-voltage power delivery through charge recycling

In this paper, we describe a technique for delivering power to a digital integrated circuit at high voltages, reducing current demands and easing requirements on power-ground network impedances. The design approach consists of stacking CMOS logic domains to operate from a voltage supply that is a multiple of the nominal supply voltage. DC-DC downconversion is performed using charge recycling without the need for explicit downconverters. Experimental results are presented for the prototype system in a 0.18-/spl mu/m CMOS technology operating at both 3.6 V and 5.4 V. Peak energy efficiencies as high as 93% are demonstrated at 3.6 V.