title: Effect of processing condition and composition on the microhardness of Cu-(2.5-10)vol.%Al₂O₃ nanocomposite powder particles produced by high energy mechanical milling

authors: Mukhtar, Aamir

subjects: processing conditions

abstract: Nanostructured Cu-(2.5-10vol.%)Al₂O₃ nanocomposites were produced using high energy mechanical milling. For the as-milled Cu- Al₂O₃ composite powder particles having Al₂O₃  volume fractions of 2.5% and 5%, the increase in average microhardness is significant with the increase of milling time from 12 hours to 24 hours. With the increase of the content of Al₂O₃ nanoparticles the microhardness increases and in the range of 255HV-270HV. The milled nanocomposite powders were heat treated at 150, 300, 400 and 500°C for 1 hour, respectively, to determine the thermal stability of the powder particles as a function of annealing temperature. The average microhardness increased/decreased for the Cu- Al₂O₃ composites after annealing at 150°C due to the dislocation density, while increasing the annealing temperature to 300°C and 400°C the average microhardness almost remained mostly unchanged. Further increasing the annealing temperature to 500°C causes significant decrease in average microhardness due to reduction in dislocation density and coarsening of Cu grains of the Cu- Al₂O₃ composite powders produced after 24 hours of milling. This paper is to report and discuss the changes of the microhardness of the material, caused by the compositions and processing conditions, used to fabricate the Cu-(2.5-10)vol.% Al₂O₃ nanocomposite powders.

text: Effect of processing condition and composition on the microhardness of Cu-(2.5-10)vol.%Al₂O₃ nanocomposite powder particles produced by high energy mechanical milling Nanostructured Cu-(2.5-10vol.%)Al₂O₃ nanocomposites were produced using high energy mechanical milling. For the as-milled Cu- Al₂O₃ composite powder particles having Al₂O₃  volume fractions of 2.5% and 5%, the increase in average microhardness is significant with the increase of milling time from 12 hours to 24 hours. With the increase of the content of Al₂O₃ nanoparticles the microhardness increases and in the range of 255HV-270HV. The milled nanocomposite powders were heat treated at 150, 300, 400 and 500°C for 1 hour, respectively, to determine the thermal stability of the powder particles as a function of annealing temperature. The average microhardness increased/decreased for the Cu- Al₂O₃ composites after annealing at 150°C due to the dislocation density, while increasing the annealing temperature to 300°C and 400°C the average microhardness almost remained mostly unchanged. Further increasing the annealing temperature to 500°C causes significant decrease in average microhardness due to reduction in dislocation density and coarsening of Cu grains of the Cu- Al₂O₃ composite powders produced after 24 hours of milling. This paper is to report and discuss the changes of the microhardness of the material, caused by the compositions and processing conditions, used to fabricate the Cu-(2.5-10)vol.% Al₂O₃ nanocomposite powders.

year: 2010

title: Instruction systolic arrays for exact parallel linear algebraic computation

authors: Krishnamurthy, V.

abstract: This thesis develops new computational algorithms for parallel/distributed error-free (exact) rational (real and complex) computing and its applications to exact linear algebraic computing. 
The practical realization of these parallel algorithms in VLSI systems using a new concept known as Instruction Systolic Arrays (ISA) is considered.
Thus, the thesis represents the author’s contribution to the theory, design, and implementation of parallel/distributed algorithms for exact rational/linear algebraic computing using ISA processors.
This thesis consists of six chapters with the following contents.

CHAPTER 1
INSTRUCTION SYSTOLIC ARRAYS - A PROGRAMMABLE PARALLEL ARCHITECTURE
Chapter 1 introduces the concept of Instruction Systolic arrays (ISA). The ISA is a new versatile programmable parallel architecture that retains all the advantages of systolic arrays. In the ISA, instructions and boolean selectors are pumped through the processing array. The ISA has tremendous potential for VLSI computing because of its ability to execute different types of programs on the same processing array. We also introduce a variant of the ISA known as the Single Instruction Systolic Array (SISA). In the SISA, single instructions and selectors are pumped through the processing array.

CHAPTER 2
INSTRUCTION SYSTOLIC ARRAYS FOR DISTRIBUTED CHINESE REMAINDERING/ INTERPOLATION ALGORITHMS
We present a parallel/ distributed algorithm for a fundamental problem in Numerical Computing/algebraic computing, namely interpolation and the closely related Chinese remaindering. The ISA implementation of this algorithm is described. A generalization of the interpolation algorithm for multivariable is then presented. The multivariable interpolation algorithm can be realized in a ISA as well as in a pyramid architecture. The Occam simulation of a pyramid for multivariable interpolation is also described. We then present a parallel/ distributed algorithm for rational function interpolation and consider its ISA implementation.

CHAPTER 3
PARALLEL MATRIX COMPUTATION USING ISA
This chapter introduces a parallel algorithm for the generalized inversion (g-inversion) of matrices, which involves parallel matrix addition and multiplication operations. The ISA implementation of this algorithm is described. The solution of a homogeneous system of linear algebraic equations is based on g-inverse computation and we indicate its ISA implementation. The solution of such equations has important practical applications in finding Petri net invariants, chemical equation balancing and dimensional analysis. Two other important g-inversion algorithms - one iterative and the other direct - are also described.

CHAPTER 4
PARALLEL ERROR-FREE RATIONAL ARITHMETIC - ISA IMPLEMENTATION
This chapter introduces a new parallel error-free (exact) rational arithmetic system called Parallel Rational Hensel code arithmetic (Para-Hensel code or PHC). We introduce algorithms for parallel element-wise arithmetic operations, and for encoding and decoding PHC codes. We briefly indicate the ISA implementation of these algorithms. We also consider the application of PHC for exact parallel matrix g-inversion with systolic processors.

CHAPTER 5
PARALLEL COMPLEX RATIONAL AND MATRIX ARITHMETIC USING GAUSSIAN PRIME CODES
In this chapter, we introduce a new parallel exact complex rational arithmetic system based on Gaussian prime codes. Two closely related methods for constructing these codes are described. The first method uses several distinct (multiple) Gaussian primes to construct Gauss-Hensel codes (GHC). The second method uses the powers of one or more Gaussian primes to construct Gauss p-adic codes (GPC). Their practical applications and extension to parallel inversion of complex matrices are described. These systems are amenable for massively parallel realization. 

CHAPTER 6 
ISA - APPLICATIONS TO ARRAY PROCESSING AND REAL-TIME COMPUTING
This chapter considers the suitability of the ISA for vector/ array processing computers. We also consider the relationship of the ISA to wavefront processing and dataflow computing. We then describe a linear variant of the ISA known as the Linear ISA (LISA), which is an area efficient architecture. We then briefly indicate some possible application areas of the ISA: real-time robot control applications and high-speed vision systems.

text: Instruction systolic arrays for exact parallel linear algebraic computation This thesis develops new computational algorithms for parallel/distributed error-free (exact) rational (real and complex) computing and its applications to exact linear algebraic computing. 
The practical realization of these parallel algorithms in VLSI systems using a new concept known as Instruction Systolic Arrays (ISA) is considered.
Thus, the thesis represents the author’s contribution to the theory, design, and implementation of parallel/distributed algorithms for exact rational/linear algebraic computing using ISA processors.
This thesis consists of six chapters with the following contents.

CHAPTER 1
INSTRUCTION SYSTOLIC ARRAYS - A PROGRAMMABLE PARALLEL ARCHITECTURE
Chapter 1 introduces the concept of Instruction Systolic arrays (ISA). The ISA is a new versatile programmable parallel architecture that retains all the advantages of systolic arrays. In the ISA, instructions and boolean selectors are pumped through the processing array. The ISA has tremendous potential for VLSI computing because of its ability to execute different types of programs on the same processing array. We also introduce a variant of the ISA known as the Single Instruction Systolic Array (SISA). In the SISA, single instructions and selectors are pumped through the processing array.

CHAPTER 2
INSTRUCTION SYSTOLIC ARRAYS FOR DISTRIBUTED CHINESE REMAINDERING/ INTERPOLATION ALGORITHMS
We present a parallel/ distributed algorithm for a fundamental problem in Numerical Computing/algebraic computing, namely interpolation and the closely related Chinese remaindering. The ISA implementation of this algorithm is described. A generalization of the interpolation algorithm for multivariable is then presented. The multivariable interpolation algorithm can be realized in a ISA as well as in a pyramid architecture. The Occam simulation of a pyramid for multivariable interpolation is also described. We then present a parallel/ distributed algorithm for rational function interpolation and consider its ISA implementation.

CHAPTER 3
PARALLEL MATRIX COMPUTATION USING ISA
This chapter introduces a parallel algorithm for the generalized inversion (g-inversion) of matrices, which involves parallel matrix addition and multiplication operations. The ISA implementation of this algorithm is described. The solution of a homogeneous system of linear algebraic equations is based on g-inverse computation and we indicate its ISA implementation. The solution of such equations has important practical applications in finding Petri net invariants, chemical equation balancing and dimensional analysis. Two other important g-inversion algorithms - one iterative and the other direct - are also described.

CHAPTER 4
PARALLEL ERROR-FREE RATIONAL ARITHMETIC - ISA IMPLEMENTATION
This chapter introduces a new parallel error-free (exact) rational arithmetic system called Parallel Rational Hensel code arithmetic (Para-Hensel code or PHC). We introduce algorithms for parallel element-wise arithmetic operations, and for encoding and decoding PHC codes. We briefly indicate the ISA implementation of these algorithms. We also consider the application of PHC for exact parallel matrix g-inversion with systolic processors.

CHAPTER 5
PARALLEL COMPLEX RATIONAL AND MATRIX ARITHMETIC USING GAUSSIAN PRIME CODES
In this chapter, we introduce a new parallel exact complex rational arithmetic system based on Gaussian prime codes. Two closely related methods for constructing these codes are described. The first method uses several distinct (multiple) Gaussian primes to construct Gauss-Hensel codes (GHC). The second method uses the powers of one or more Gaussian primes to construct Gauss p-adic codes (GPC). Their practical applications and extension to parallel inversion of complex matrices are described. These systems are amenable for massively parallel realization. 

CHAPTER 6 
ISA - APPLICATIONS TO ARRAY PROCESSING AND REAL-TIME COMPUTING
This chapter considers the suitability of the ISA for vector/ array processing computers. We also consider the relationship of the ISA to wavefront processing and dataflow computing. We then describe a linear variant of the ISA known as the Linear ISA (LISA), which is an area efficient architecture. We then briefly indicate some possible application areas of the ISA: real-time robot control applications and high-speed vision systems.

year: 1988

title: Teaching Māori in English-medium schools in New Zealand: Teacher responses to aspects of the curriculum guidelines for te reo Māori in English-medium school settings

authors: Takurua, Nātana

subjects: New Zealand

abstract: Opinions are divided about how the content of language courses should be specified and whether educational authorities should include specifications/ suggestions about language content in national curriculum documents. Issues associated with language content are, however, not ones that can be avoided, particularly as teachers are expected to prepare students for national examinations at the upper levels of schooling and these examinations are necessarily predicated on general expectations about proficiency achievements and more specific expectations about the types of language with which students will be familiar. In this article, we explore the complex nature of some of the issues involved and the ways in which the New Zealand Ministry of Education has sought/ is seeking to resolve them in the case of the curriculum for Māori in English-medium schools. We also report on the responses of a sample of teachers of Māori in secondary schools in New Zealand to the omission of language examples from the final version of the curriculum guidelines document.

text: Teaching Māori in English-medium schools in New Zealand: Teacher responses to aspects of the curriculum guidelines for te reo Māori in English-medium school settings Opinions are divided about how the content of language courses should be specified and whether educational authorities should include specifications/ suggestions about language content in national curriculum documents. Issues associated with language content are, however, not ones that can be avoided, particularly as teachers are expected to prepare students for national examinations at the upper levels of schooling and these examinations are necessarily predicated on general expectations about proficiency achievements and more specific expectations about the types of language with which students will be familiar. In this article, we explore the complex nature of some of the issues involved and the ways in which the New Zealand Ministry of Education has sought/ is seeking to resolve them in the case of the curriculum for Māori in English-medium schools. We also report on the responses of a sample of teachers of Māori in secondary schools in New Zealand to the omission of language examples from the final version of the curriculum guidelines document.

year: 2009-09