A portable load cell for in-situ ore impact breakage testing

This paper discusses the design and characterisation of a short, and hence portable impact load cell for in-situ quantification of ore breakage properties under impact loading conditions. Much literature has been published in the past two decades about impact load cells for ore breakage testing. It has been conclusively shown that such machines yield significant quantitative energy-fragmentation information about industrial ores. However, documented load cells are all laboratory systems that are not adapted for in-situ testing due to their dimensions and operating requirements. The authors report on a new portable impact load cell designed specifically for in-situ testing. The load cell is 1.5 m in height and weighs 30 kg. Its physical and operating characteristics are detailed in the paper. This includes physical dimensions, calibration and signal deconvolution. Emphasis is placed on the deconvolution issue, which is significant for such a short load cell. Finally, it is conclusively shown that the short load cell is quantitatively as accurate as its larger laboratory analogues

Pilot Project - Demonstration of Load Rating Capabilities through Physical Load Testing: Tech Transfer Summary, RB32-013, 2013

This project demonstrated the capabilities for load testing bridges in Iowa, developed and presented a webinar to local and state engineers, and produced a spreadsheet and benefit evaluation matrix that others can use to preliminarily assess where bridge testing may be economically feasible given truck traffic and detour lengths

Demonstration of Load Rating Capabilities through Physical Load Testing: Sioux County Bridge Case Study, RB32-013, 2013

The objective of this work, Pilot Project - Demonstration of Capabilities and Benefits of Bridge Load Rating through Physical Testing, was to demonstrate the capabilities for load testing and rating bridges in Iowa, study the economic benefit of performing such testing, and perform outreach to local, state, and national engineers on the topic of bridge load testing and rating. This report documents one of three bridges inspected, load tested, and load rated as part of the project, the Sioux County Bridge (FHWA #308730), including testing procedures and performance of the bridge under static loading along with the calculated load rating from the field-calibrated analytical model. Two parallel reports document the testing and load rating of the Ida County Bridge (FHWA #186070) and the Johnson County Bridge (FHWA #205750). A tech brief provides overall information about the project

Range-based attacks on links in random scale-free networks

$Range$ and $load$ play keys on the problem of attacking on links in random scale-free (RSF) networks. In this Brief Report we obtain the relation between $range$ and $load$ in RSF networks analytically by the generating function theory, and then give an estimation about the impact of attacks on the $efficiency$ of the network. The analytical results show that short range attacks are more destructive for RSF networks, and are confirmed numerically. Further our results are consistent with the former literature (Physical Review E \textbf{66}, 065103(R) (2002))

A comparison of different types of probes for detecting electromanetic emission

This paper deals with a comparison of different types of probes for detecting electromagnetic emission (EME). The matter of investigation is EME from a model which generates cracks of samples under load. This article provides a description of probes for EME measurement signals. The novelty of the approach lies in the fact that the physical model was used instead of real samples under uniaxial load of composite materials. The author also describes the experiment conducted for obtaining signals and analyses the digitized signals as waveforms and spectra. Appropriate conclusions were made according to the comparative analysis

Online Voltage Stability Assessment for Load Areas Based on the Holomorphic Embedding Method

This paper proposes an online steady-state voltage stability assessment scheme to evaluate the proximity to voltage collapse at each bus of a load area. Using a non-iterative holomorphic embedding method (HEM) with a proposed physical germ solution, an accurate loading limit at each load bus can be calculated based on online state estimation on the entire load area and a measurement-based equivalent for the external system. The HEM employs a power series to calculate an accurate Power-Voltage (P-V) curve at each load bus and accordingly evaluates the voltage stability margin considering load variations in the next period. An adaptive two-stage Pade approximants method is proposed to improve the convergence of the power series for accurate determination of the nose point on the P-V curve with moderate computational burden. The proposed method is illustrated in detail on a 4-bus test system and then demonstrated on a load area of the Northeast Power Coordinating Council (NPCC) 48-geneartor, 140-bus power system.Comment: Revised and Submitted to IEEE Transaction on Power System

Characterising gross plastic deformation in design by analysis

An investigation of three simple structures is conducted to identify and characterise the condition of gross plastic deformation in pressure vessel design by analysis. Limit analysis and bilinear hardening plastic analysis is performed for three simple example problems. It is found that previously proposed plastic criteria do not fully represent the effect of the hardening material model on the development of the plastic failure mechanism. A new criterion of plastic collapse based on the curvature of the load–plastic work history is therefore proposed. This is referred to as the Plastic Work Curvature or PWC criterion. It is shown that salient points of curvature correspond to critical stages in the physical evolution of the gross plastic deformation mechanism. The PWC criterion accounts for the effect of the bilinear hardening model on the development of the plastic mechanism and gives an enhanced plastic load when compared to the limit load

Switched Capacitor Voltage Converter

This project supports IoT development by reducing the power con- sumption and physical footprint of voltage converters. Our switched- capacitor IC design steps down an input of 1:0 - 1:4 V to 0:6 V for a decade of load current from 5 - 50A