title: On microstructural evolution and mechanical properties of Ti-5Al-5V-5Mo-3Cr alloy synthesised from elemental powder mixtures

authors: Yang, Fei

subjects: Science & Technology

abstract: In this paper, we explored to prepare a multi-compositional titanium alloy, Ti-5Al-5V-5Mo-3Cr (Ti-5553), by powder compact extrusion from elemental powder mixtures, and investigate the microstructure variation during the synthesising process and after post heat treatments and the changes of mechanical properties. XRD, OM and SEM were used to analyse the phase constitutions and microstructures of the Ti-5553 alloy at different processing conditions, and tensile tests were conducted to examine their mechanical properties. The results showed that a homogeneous Ti-5553 alloy was successfully produced by powder compact extrusion from the powder mixtures, β phase was mainly contained in the hot-pressed and 1200°C-extruded Ti-5553 alloy and had an equiaxed microstructure. Different types of α phase precipitated from the β matrix after heat treatment, and this significantly changed the microstructures and improved the mechanical properties of the extruded Ti-5553 alloy, with yield strength of 1250 MPa and ultimate strength of 1300 MPa for the alloy treated at 675 °C for 2 h, and the ductility of about 6.1% for the alloy treated at 780 °C for 2 h.

text: On microstructural evolution and mechanical properties of Ti-5Al-5V-5Mo-3Cr alloy synthesised from elemental powder mixtures In this paper, we explored to prepare a multi-compositional titanium alloy, Ti-5Al-5V-5Mo-3Cr (Ti-5553), by powder compact extrusion from elemental powder mixtures, and investigate the microstructure variation during the synthesising process and after post heat treatments and the changes of mechanical properties. XRD, OM and SEM were used to analyse the phase constitutions and microstructures of the Ti-5553 alloy at different processing conditions, and tensile tests were conducted to examine their mechanical properties. The results showed that a homogeneous Ti-5553 alloy was successfully produced by powder compact extrusion from the powder mixtures, β phase was mainly contained in the hot-pressed and 1200°C-extruded Ti-5553 alloy and had an equiaxed microstructure. Different types of α phase precipitated from the β matrix after heat treatment, and this significantly changed the microstructures and improved the mechanical properties of the extruded Ti-5553 alloy, with yield strength of 1250 MPa and ultimate strength of 1300 MPa for the alloy treated at 675 °C for 2 h, and the ductility of about 6.1% for the alloy treated at 780 °C for 2 h.

year: 2018

title: Bacteriological control food equipment by cleaning systems

authors: Dunsmore, David George

abstract: This study was undertaken to examine the performance of cleaning systems applied to food equipment. The contribution by the components of those systems to the performance of the total system was determined.
A cleaning simulator was constructed in which test pieces in 4 test cells were subjected to 25 to 35 cycles, each of 12h. Each cycle the test pieces were: soiled for 45 min. in pasteurised milk (at 30°c) dosed with 10⁶ bacteria/ml of Streptococcus faecalis, Escherichia coli or Enterobacter aerogenes; serially treated with the rinses, detergents and sanitizers of the experimental cleaning system; and left for 9.5h intercycle (rest) period. The changes in the soil mass with time on stainless steel, rubber and glass test pieces were determined gravimetrically. The changes in the numbers of the dosed and non-dosed organisms on the surfaces, after components of the cleaning system had been applied, were determined by a swab-recovery/ plate-counting system. The surfaces were also examined by scanning electron microscopy. Four experiments were performed using this technique.
A field experiment examined the performance of 5 cleaning systems over experimental periods of 5 weeks on 15 milking machines. 
The nature of the changes in the performance of the cleaning system over time were determined. Both detergents and sanitizers could, under varying conditions, contribute significantly to the bacteriological performance achieved by the system. A sanitizer applied for the complete intercycle period was more efficient than those applied for short contact-times. A post-wash sanitizer was slightly more efficient than a sanitizer applied before milking. 
The cycle of bacterial deposition onto the equipment surfaces, attachment, depletion by the cleaning system, growth during the intercycle period, and subsequent contamination of the milk at the next milking was studied. All three dose organisms attached actively, and were then largely removed by the cleaning system. Despite there being a large amount of soil on the surfaces of the test pieces, the intercycle conditions (30°c at up to 90% RH for 9.5h) were insufficient for growth. The effect of the amount of soil on the surface on the ability of bacteria to survive the application of a system or system component was examined. The minimum soil levels necessary for an organism to survive a treatment (Total Effect Maximum) and the minimum soil necessary for all organisms to survive a treatment (Zero Effect Minimum) were determined for systems and system components. 
The data was used to discuss the principles to be followed in designing a cleaning system. The principles were applied to the design of a system to clean a milking machine with cold solutions by soak techniques.

text: Bacteriological control food equipment by cleaning systems This study was undertaken to examine the performance of cleaning systems applied to food equipment. The contribution by the components of those systems to the performance of the total system was determined.
A cleaning simulator was constructed in which test pieces in 4 test cells were subjected to 25 to 35 cycles, each of 12h. Each cycle the test pieces were: soiled for 45 min. in pasteurised milk (at 30°c) dosed with 10⁶ bacteria/ml of Streptococcus faecalis, Escherichia coli or Enterobacter aerogenes; serially treated with the rinses, detergents and sanitizers of the experimental cleaning system; and left for 9.5h intercycle (rest) period. The changes in the soil mass with time on stainless steel, rubber and glass test pieces were determined gravimetrically. The changes in the numbers of the dosed and non-dosed organisms on the surfaces, after components of the cleaning system had been applied, were determined by a swab-recovery/ plate-counting system. The surfaces were also examined by scanning electron microscopy. Four experiments were performed using this technique.
A field experiment examined the performance of 5 cleaning systems over experimental periods of 5 weeks on 15 milking machines. 
The nature of the changes in the performance of the cleaning system over time were determined. Both detergents and sanitizers could, under varying conditions, contribute significantly to the bacteriological performance achieved by the system. A sanitizer applied for the complete intercycle period was more efficient than those applied for short contact-times. A post-wash sanitizer was slightly more efficient than a sanitizer applied before milking. 
The cycle of bacterial deposition onto the equipment surfaces, attachment, depletion by the cleaning system, growth during the intercycle period, and subsequent contamination of the milk at the next milking was studied. All three dose organisms attached actively, and were then largely removed by the cleaning system. Despite there being a large amount of soil on the surfaces of the test pieces, the intercycle conditions (30°c at up to 90% RH for 9.5h) were insufficient for growth. The effect of the amount of soil on the surface on the ability of bacteria to survive the application of a system or system component was examined. The minimum soil levels necessary for an organism to survive a treatment (Total Effect Maximum) and the minimum soil necessary for all organisms to survive a treatment (Zero Effect Minimum) were determined for systems and system components. 
The data was used to discuss the principles to be followed in designing a cleaning system. The principles were applied to the design of a system to clean a milking machine with cold solutions by soak techniques.

year: 1978

title: Hone Werahiko: the discoverer of gold at Te Aroha

authors: Hart, Philip

abstract: Originally Hone Kahukahu, when he was living at Ohinemutu in the 1860s he became known as Hone Werahiko, an Arawa name he retained for the rest of his life. His father, a member of Ngati Kahungungu, had been captured by Arawa; his mother was a Waikato. A widow living at Maketu chose him as her second husband because he was ‘a good looking fellow & understood English’. 
In the late 1860s and much of the 1870s, he prospected in Hauraki and even in the King Country, and worked underground in a Thames mine, the only Maori known to have done so. But in the early 1870s he gave up mining to be a pioneer publican and storekeeper at Ohinemutu, at Rotorua. He acquired land and property there, but after his wife died he returned to prospecting full-time. 
Werahiko’s first investigation of Te Aroha was in 1877, when he was ordered off by the local hapu. He returned in 1880 as the head of a prospecting party subsidized by the government. After finding gold, he was granted the Prospectors’ Claim and, in due course, a reward, and for a time supervised its development. Investing in other claims, he traded in shares. When his discovery turned out to be a duffer, he explored other parts of the mountain, first having high hopes for the Tui portion but then, after four months of exploring over winter with the support of three other Maori, he announced the discovery of his New Find at Waiorongomai. Once again he acquired partners, mostly Paheka, and traded in shares, and for some time supervised the opening up of his new find.
Later, he was invited to prospect the King Country, but this did not eventuate. His last involvement in mining was at Karangahake. Because of the hardships of his prospecting at Te Aroha, he died at an early age, leaving a young second wife. His memory lived on, amongst Pakeha miners in particular, because he had the rare distinction for a prospector of being regarded as totally honest, and he was admired for succeeding when so many others had failed.

[Note: Especially when he first came to public attention, many Pakeha struggled with Hone Werahiko’s name, which was recorded in a variety of incorrect forms, the worst example being Hoani Whaekareka.  Even the warden at first gave his name as Hone Wharekino.  Many Pakeha found it simpler to refer to him as ‘Johnny the Maori’.  In this paper, his name is given correctly throughout.]

text: Hone Werahiko: the discoverer of gold at Te Aroha Originally Hone Kahukahu, when he was living at Ohinemutu in the 1860s he became known as Hone Werahiko, an Arawa name he retained for the rest of his life. His father, a member of Ngati Kahungungu, had been captured by Arawa; his mother was a Waikato. A widow living at Maketu chose him as her second husband because he was ‘a good looking fellow & understood English’. 
In the late 1860s and much of the 1870s, he prospected in Hauraki and even in the King Country, and worked underground in a Thames mine, the only Maori known to have done so. But in the early 1870s he gave up mining to be a pioneer publican and storekeeper at Ohinemutu, at Rotorua. He acquired land and property there, but after his wife died he returned to prospecting full-time. 
Werahiko’s first investigation of Te Aroha was in 1877, when he was ordered off by the local hapu. He returned in 1880 as the head of a prospecting party subsidized by the government. After finding gold, he was granted the Prospectors’ Claim and, in due course, a reward, and for a time supervised its development. Investing in other claims, he traded in shares. When his discovery turned out to be a duffer, he explored other parts of the mountain, first having high hopes for the Tui portion but then, after four months of exploring over winter with the support of three other Maori, he announced the discovery of his New Find at Waiorongomai. Once again he acquired partners, mostly Paheka, and traded in shares, and for some time supervised the opening up of his new find.
Later, he was invited to prospect the King Country, but this did not eventuate. His last involvement in mining was at Karangahake. Because of the hardships of his prospecting at Te Aroha, he died at an early age, leaving a young second wife. His memory lived on, amongst Pakeha miners in particular, because he had the rare distinction for a prospector of being regarded as totally honest, and he was admired for succeeding when so many others had failed.

[Note: Especially when he first came to public attention, many Pakeha struggled with Hone Werahiko’s name, which was recorded in a variety of incorrect forms, the worst example being Hoani Whaekareka.  Even the warden at first gave his name as Hone Wharekino.  Many Pakeha found it simpler to refer to him as ‘Johnny the Maori’.  In this paper, his name is given correctly throughout.]

year: 2016