Mechanical property of calcareous sand under action of compaction

Calcareous sand is a kind of special medium which is composed of calcium carbonate and other difficult soluble carbonate substances. Because of its rich in inner pore space and easy crashed,the mechanical property is very different from conventional quartz sand. Based on the compaction test and direct shear test of calcareous sand,by means of data fitting,the coupling relationship between compaction density and mechanical property under different water contents was obtained; meanwhile,the shear strength expression was built on the basis of the relationship between water content and dry density.

Research on the different content of weathered sand influence on expansive characteristic of a highway expansive soil in Yichang

This paper aims at widespread presence of expansive soil which can be obtained in the project from Xiaoxita to Yaqueling first-class highway rebuilding engineering in Yichang City of Hubei Province and weathered sand which can be made full use locally,many experiments have been made. Compaction experiments and expansibility index indoor experiments of undisturbed expansive soil and expansive soil mixed with sand ranging from 10 % to 50 % have been made. Through the test mixing undisturbed expansive soil with different content of weathered sand,it can change the expansive soil water characteristics and compaction characteristics. It can influence the expansibility of the expansive soil index and significantly inhibit the expansibility of the expansive soil and reach the standard of roadbed filler.

Efficient Static Compaction of Test Patterns Using Partial Maximum Satisfiability

Static compaction methods aim at finding unnecessary test patterns to reduce the size of the test set as a post-process of test generation.Techniques based on partial maximum satisfiability are often used to track many hard problems in various domains,including artificial intelligence,computational biology,data mining,and machine learning.We observe that part of the test patterns generated by the commercial Automatic Test Pattern Generation(ATPG)tool is redundant,and the relationship between test patterns and faults,as a significant information,can effectively induce the test patterns reduction process.Considering a test pattern can detect one or more faults,we map the problem of static test compaction to a partial maximum satisfiability problem.Experiments on ISCAS89,ISCAS85,and ITC99 benchmarks show that this approach can reduce the initial test set size generated by TetraMAX18 while maintaining fault coverage.

Functional-Level Fault Simulation with Concurrent and Parallel Mechanisms Using Object-Oriented VLSI Model

The functional-level test has been proposed as an alternative to reduce the complexity of test when VLSI gets larger and more complicated. It has been successful for circuits such as memories, PLAs and microprocessors. However, the functional-level test for general functional models has seldom been studied. This paper presents an object-oriented VLSI model and a functional-level fault simulation methodology for general functional model. Based on the proposed VLSI model, FFS (Functional-level Fault Simulator) with friendly visual interface has been implemented on Microsoft Windows platform by use of C++. It is an integral part of FMVS (Functional test Modeling and Verification System)-an extended subsystem of TeDS (Test Development System). The goal of FFS is to determine the fault coverage, generate fault dictionary and compact original test set at the function-level. In order to be efficient, FFS uses the concurrent and parallel mechanisms by taking advantage of the object-oriented VLSI model. The object-oriented VLSI model based fault simulation has been validated in the functional-level test by simulation results and the satisfying performance of FFS.