Management Guidelines for New Warm-Season Grasses in Australia

After more than 30 years in which ‘Tifgreen’ and ‘Tifdwarf’ were the only greens-quality varieties available, the choice for golf courses and bowls clubs in northern Australia has been expanded to include six new Cynodon hybrids [Cynodon dactylon (L.) Pers x Cynodon transvaalensis Burtt-Davy]. Five of these – ‘Champion Dwarf’ (Texas), ‘MS-Supreme’ (Mississippi), FloraDwarf™ (Florida), ‘TifEagle’ (Georgia), MiniVerde™ (Arizona) - are from US breeding programs, while the sixth, ‘TL2’ (marketed as Novotek™) was selected in north Queensland. The finer, denser and lower growing habit of the “ultradwarf” cultivars allows very low mowing heights (e.g. 2.5 mm) to be imposed, resulting in denser and smoother putting and bowls surfaces. In addition to the Cynodon hybrids, four new greens quality seashore paspalum (Paspalum vaginatum O. Swartz) cultivars including ‘Sea Isle 2000’, Sea Isle Supreme™, Velvetene™ and Sea Dwarf™ (where tolerance of salty water is required) expands the range of choices for greens in difficult environments. The project was developed to determine (a) the appropriate choice of cultivar for different environments and budgets, and (b) best management practices for the new cultivars which differ from the Cynodon hybrid industry standards ‘Tifgreen’ and ‘Tifdwarf’. Management practices, particularly fertilising, mowing heights and frequency, and thatch control were investigated to determine optimum management inputs and provide high quality playing surfaces with the new grasses. To enable effective trialling of these new and old cultivars it was essential to have a number of regional sites participating in the study. Drought and financial hardship of many clubs presented an initial setback with numerous clubs wanting to be involved in the study but were unable to commit due to their financial position at the time. The study was fortunate to have seven regional sites from Queensland, New South Wales, Victoria and South Australia volunteer to be involved in the study which would add to the results being collected at the centralised test facility being constructed at DEEDI’s Redlands Research Station. The major research findings acquired from the eight trial sites included: • All of the new second generation “ultradwarf” couchgrasses tend to produce a large amount of thatch with MiniVerde™ being the greatest thatch producer, particularly compared to ‘Tifdwarf’ and ‘Tifgreen’. The maintenance of the new Cynodon hybrids will require a program of regular dethatching/grooming as well as regular light dustings of sand. Thatch prevention should begin 3 to 4 weeks after planting a new “ultradwarf” couchgrass green, with an emphasis on prevention rather than control. • The “ultradwarfs” produced faster green speeds than the current industry standards ‘Tifgreen’ and ‘Tifdwarf’. However, all Cynodon hybrids were considerably faster than the seashore paspalums (e.g. comparable to the speed diference of Bentgrass and couchgrass) under trial conditions. Green speed was fastest being cut at 3.5 mm and rolled (compared to 3.5 mm cut, no roll and 2.7 mm cut, no roll). • All trial sites reported the occurrence of disease in the Cynodon hybrids with the main incidence of disease occurring during the dormancy period (autumn and winter). The main disease issue reported was “patch diseases” which includes both Gaumannomyces and Rhizoctonia species. There was differences in the severity of the disease between cultivars, however, the severity of the disease was not consistent between cultivars and is largely attributed to an environment (location) effect. In terms of managing the occurrence of disease, the incidence of disease is less severe where there is a higher fertility rate (about 3 kgN/100m2/year) or a preventitatve fungicide program is adopted. • Cynodon hybrid and seashore paspalum cultivars maintained an acceptable to ideal surface being cut between 2.7 mm and 5.0 mm. “Ultradwarf” cultivars can tolerate mowing heights as low as 2.5 mm for short periods but places the plant under high levels of stress. Greens being maintained at a continually lower cutting height (e.g. 2.7 mm) of both species is achievable, but would need to be cut daily for best results. Seashore paspalums performed best when cut at a height of between 2.7 mm and 3.0 mm. If a lower cutting height is adopted, regular and repeated mowings are required to reduce scalping and produce a smooth surface. • At this point in time the optimum rate of nitrogen (N) for the Cynodon hybrids is 3 kg/100m2/year and while the seashore paspalums is 2 to 3 kg/100m2/year. • Dormancy occurred for all Cynodon and seashore paspalum culitvars from north in Brisbane (QLD) to south in Mornington Peninsula (VIC) and west to Novar Gardens (SA). Cynodon and Paspalum growth in both Victoria and South Australia was less favourable as a result of the cooler climates. • After combining the data collected from all eight sites, the results indicated that there can be variation (e.g. turfgrass quality, colour, disease resistance, performace) depending on the site and climatic conditions. Such evidence highlights the need to undertake genotype by environment (G x E) studies on new and old cultivars prior to conversion or establishment. • For a club looking to select either a Cynodon hybrid or seashore paspalum cultivar for use at their club they need to: - Review the research data. - Look at trial plots. - Inspect greens in play that have the new grasses. - Select 2 to 3 cultivars that are considered to be the better types. - Establish them in large (large enough to putt on) plots/nursery/practice putter. Ideally the area should be subjected to wear. - Maintain them exactly as they would be on the golf course/lawn bowls green. This is a critical aspect. Regular mowing, fertilising etc. is essential. - Assess them over at least 2 to 3 years. - Make a selection and establish it in a playing green so that it is subjected to typical wear.

Best management practices for sustainable and safe playing surface of Australian Football League sports fields

In 2002, AFL Queensland and the Brisbane Lions Football Club approached the Department of Primary Industries and Fisheries (Queensland) for advice on improving their Premier League sports fields. They were concerned about player safety and dissatisfaction with playing surfaces, particularly uneven turf cover and variable under-foot conditions. They wanted to get the best from new investments in ground maintenance equipment and irrigation infrastructure. Their sports fields were representative of community-standard, multi-use venues throughout Australia; generally ‘natural’ soil fields, with low maintenance budgets, managed by volunteers. Improvements such as reconstruction, drainage, or regular re-turfing are generally not affordable. Our project aimed to: (a) Review current world practice and performance benchmarks; (b) Demonstrate best-practice management for community-standard fields; (c) Adapt relevant methods for surface performance testing; (d) Assess current soils, and investigate useful amendments; (e) Improve irrigation system performance; and (e) Build industry capacity and encourage patterns for ongoing learning. Most global sports field research focuses on elite, sand-based fields. We adjusted elite standards for surface performance (hardness, traction, soil moisture, evenness, sward cover/height) and maintenance programs, to suit community-standard fields with lesser input resources. In regularly auditing ground conditions across 12 AFLQ fields in SE QLD, we discovered surface hardness (measured by Clegg Hammer) was the No. 1 factor affecting player safety and surface performance. Other important indices were turf coverage and surface compaction (measured by penetrometer). AFLQ now runs regularly audits affiliated fields, and closes grounds with hardness readings greater than 190 Gmax. Aerating every two months was the primary mechanical practice improving surface condition and reducing hardness levels to < 110 Gmax on the renovated project fields. With irrigation installation, these fields now record surface conditions comparable to elite fields. These improvements encouraged many other sporting organisations to seek advice / assistance from the project team. AFLQ have since substantially invested in an expanded ground improvement program, to cater for this substantially increased demand. In auditing irrigation systems across project fields, we identified low maintenance (with < 65% of sprinklers operating optimally) as a major problem. Retrofitting better nozzles and adjusting sprinklers improved irrigation distribution uniformity to 75-80%. Research showed that reducing irrigation frequency to weekly, and preparedness to withhold irrigation longer after rain, reduced irrigation requirement by 30-50%, compared to industry benchmarks of 5-6 ML/ha/annum. Project team consultation with regulatory authorities enhanced irrigation efficiency under imposed regional water restrictions. Laboratory studies showed incorporated biosolids / composts, or topdressed crumb rubber, improved compaction resistance of soils. Field evaluations confirmed compost incorporation significantly reduced surface hardness of high wear areas in dry conditions, whilst crumb rubber assisted turf persistence into early winter. Neither amendment was a panacea for poor agronomic practices. Under the auspices of the project Trade Mark Sureplay®, we published > 80 articles, and held > 100 extension activities involving > 2,000 participants. Sureplay® has developed a multi-level curator training structure and resource materials, subject to commercial implementation. The partnerships with industry bodies (particularly AFLQ), frequent extension activities, and engagement with government/regulatory sectors have been very successful, and are encouraged for any future work. Specific aspects of sports field management for further research include: (a) Understanding of factors affecting turf wear resistance and recovery, to improve turf persistence under wear; (b) Simple tests for pinpointing areas of fields with high hardness risk; and (c) Evaluation of new irrigation infrastructure, ‘water-saving’ devices, and irrigation protocols, in improving water use and turf cover outcomes.

Performance of an Al-Si-graphite particle composite piston in a diesel engine

Al-Si-graphite particle composite alloy pistons containing different percentages of about 80 μm uncoated graphite particles were successfully cast by foundry techniques. Tests with a 5 hp single-cylinder diesel engine show that Al-Si-graphite particle composite pistons can withstand an endurance test of 500 h without any apparent deterioration and do not seize during the running-in period. The use of the Al-Si-3% graphite particle composite piston also results in (a) up to 3% reduction in the specific fuel consumption, (b) considerable reduction in the wear of all four piston rings, (c) a reduction in piston wear, (d) a 9% reduction in the frictional horsepower losses of the engine as determined by the motoring test and (e) a slight increase in the exhaust gas temperature. These reductions (a)–(d) appear to be due to increased lubrication from the graphite particles which are smeared on the bearing surface, the higher damping capacity of the composite pistons and the reduced coefficient of thermal expansion of the composite pistons. Preliminary results indicate that aluminum-graphite particle composite alloy is a promising material for automotive pistons.

Traffic tolerance of warm season turfgrasses under Community Sportsfield Conditions

The four-year Horticulture Australia (HAL) project is the first scientific study within Australia to assess simulated and actual wear studies of warm-season turfgrasses suitable for sportfield use. The study has allowed researchers and turf professionals to compare traffic (wear and compaction) tolerance and turf management requirements (e.g. mowing) of the current dominant varieties.

Compression use during an exercise intervention and associated changes in breast cancer-related lymphoedema

Aim This study assessed the association between compression use and changes in lymphoedema observed in women with breast cancer-related lymphoedema who completed a 12 week exercise intervention. Methods This work uses data collected from a 12 week exercise trial, whereby women were randomly allocated into either aerobic-based only (n=21) or resistance-based only (n=20) exercise. Compression use during the trial was at the participant’s discretion. Differences in lymphoedema (measured by L-Dex score and inter-limb circumference difference [%]) and associated symptoms between those who wore, and did not wear compression during the 12 week intervention were assessed. We also explored participants’ reasons surrounding compression during exercise. Results No significant interaction effect between time and compression use for lymphoedema was observed. There was no difference between groups over time in the number or severity of lymphoedema symptoms. Irrespective of compression use, there were trends for reductions in the proportion of women reporting severe symptoms, but lymphoedema status did not change. Individual reasons for the use of compression, or lack thereof, varied markedly. Conclusion Our findings demonstrated an absence of a positive or negative effect from compression use during exercise on lymphoedema. Current and previous findings suggest the clinical recommendation that garments must be worn during exercise is questionable, and its application requires an individualised approach.

Optical and surface characterization of radio frequency plasma polymerized 1-isopropyl-4-methyl-1,4-cyclohexadiene thin films

Low pressure radio frequency plasma-assisted deposition of 1-isopropyl-4-methyl-1,4-cyclohexadiene thin films was investigated for different polymerization conditions. Transparent, environmentally stable and flexible, these organic films are promising candidates for organic photovoltaics (OPV) and flexible electronics applications, where they can be used as encapsulating coatings and insulating interlayers. The effect of deposition RF power on optical properties of the films was limited, with all films being optically transparent, with refractive indices in a range of 1.57–1.58 at 500 nm. The optical band gap (Eg) of ~3 eV fell into the insulating Eg region, decreasing for films fabricated at higher RF power. Independent of deposition conditions, the surfaces were smooth and defect-free, with uniformly distributed morphological features and average roughness between 0.30 nm (at 10 W) and 0.21 nm (at 75 W). Films fabricated at higher deposition power displayed enhanced resistance to delamination and wear, and improved hardness, from 0.40 GPa for 10 W to 0.58 GPa for 75 W at a load of 700 μN. From an application perspective, it is therefore possible to tune the mechanical and morphological properties of these films without compromising their optical transparency or insulating property.

Nanotribological and nanomechanical properties of plasma-polymerized polyterpenol thin films

Organic plasma polymers are currently attracting significant interest for their potential in the areas of flexible optoelectronics and biotechnology. Thin films of plasma-polymerized polyterpenol fabricated under varied deposition conditions were studied using nanoindentation and nanoscratch analyses. Coatings fabricated at higher deposition power were characterized by improved hardness, from 0.33 GPa for 10 W to 0.51 GPa for 100 W at 500-μN load, and enhanced wear resistance. The elastic recovery was estimated to be between 0.1 and 0.14. Coatings deposited at higher RF powers also showed less mechanical deformation and improved quality of adhesion. The average (R a) and root mean square (R q) surface roughness parameters decreased, from 0.44 nm and 0.56 nm for 10 W to 0.33 nm and 0.42 nm for 100 W, respectively.

Fabrication and characterization of plasma polymer thin films from monoterpene alcohols for applications in organic electronics and biotechnology

After more than twenty years of basic and applied research, the use of nanotechnology in the design and manufacture of nanoscale materials is rapidly increasing, particularly in commercial applications that span from electronics across renewable energy areas, and biomedical devices. Novel polymers are attracting significant attention for they promise to provide a low−cost high−performance alternative to existing materials. Furthermore, these polymers have the potential to overcome limitations imposed by currently available materials thus enabling the development of new technologies and applications that are currently beyond our reach. This work focuses on the development of a range of new low−cost environmentally−friendly polymer materials for applications in areas of organic (flexible) electronics, optics, and biomaterials. The choice of the monomer reflects the environmentally−conscious focus of this project. Terpinen−4−ol is a major constituent of Australian grown Melaleuca alternifolia (tea tree) oil, attributed with the oil's antimicrobial and anti−inflammatory properties. Plasma polymerisation was chosen as a deposition technique for it requires minimal use of harmful chemicals and produces no hazardous by−products. Polymer thin films were fabricated under varied process conditions to attain materials with distinct physico−chemical, optoelectrical, biological and degradation characteristics. The resultant materials, named polyterpenol, were extensively characterised using a number of well−accepted and novel techniques, and their fundamental properties were defined. Polyterpenol films were demonstrated to be hydrocarbon rich, with variable content of oxygen moieties, primarily in the form of hydroxyl and carboxyl functionalities. The level of preservation of original monomer functionality was shown to be strongly dependent on the deposition energy, with higher applied power increasing the molecular fragmentation and substrate temperature. Polyterpenol water contact angle contact angle increased from 62.7° for the 10 W samples to 76.3° for the films deposited at 100 W. Polymers were determined to resist solubilisation by water, due to the extensive intermolecular and intramolecular hydrogen bonds present, and other solvents commonly employed in electronics and biomedical processing. Independent of deposition power, the surface topography of the polymers was shown to be smooth (Rq <0.5 nm), uniform and defect free. Hardness of polyterpenol coatings increased from 0.33 GPa for 10 W to 0.51 GPa for 100 W (at 500 μN load). Coatings deposited at higher input RF powers showed less mechanical deformation during nanoscratch testing, with no considerable damage, cracking or delamination observed. Independent of the substrate, the quality of film adhesion improved with RF power, suggesting these coatings are likely to be more stable and less susceptible to wear. Independent of fabrication conditions, polyterpenol thin films were optically transparent, with refractive index approximating that of glass. Refractive index increased slightly with deposition power, from 1.54 (10 W) to 1.56 (100 W) at 500 nm. The optical band gap values declined with increasing power, from 2.95 eV to 2.64 eV, placing the material within the range for semiconductors. Introduction of iodine impurity reduced the band gap of polyterpenol, from 2.8 eV to 1.64 eV, by extending the density of states more into the visible region of the electromagnetic spectrum. Doping decreased the transparency and increased the refractive index from 1.54 to 1.70 (at 500 nm). At optical frequencies, the real part of permittivity (k) was determined to be between 2.34 and 2.65, indicating a potential low-k material. These permittivity values were confirmed at microwave frequencies, where permittivity increased with input RF energy – from 2.32 to 2.53 (at 10 GHz ) and from 2.65 to 2.83 (at 20 GHz). At low frequencies, the dielectric constant was determined from current−voltage characteristics of Al−polyterpenol−Al devices. At frequencies below 100 kHz, the dielectric constant varied with RF power, from 3.86 to 4.42 at 1 kHz. For all samples, the resistivity was in order of 10⁸−10⁹ _m (at 6 V), confirming the insulating nature of polyterpenol material. In situ iodine doping was demonstrated to increase the conductivity of polyterpenol, from 5.05 × 10⁻⁸ S/cm to 1.20 × 10⁻⁶ S/cm (at 20 V). Exposed to ambient conditions over extended period of time, polyterpenol thin films were demonstrated to be optically, physically and chemically stable. The bulk of ageing occurred within first 150 h after deposition and was attributed to oxidation and volumetric relaxation. Thermal ageing studies indicated thermal stability increased for the films manufactured at higher RF powers, with degradation onset temperature associated with weight loss shifting from 150 ºC to 205 ºC for 10 W and 100 W polyterpenol, respectively. Annealing the films to 405 °C resulted in full dissociation of the polymer, with minimal residue. Given the outcomes of the fundamental characterisation, a number of potential applications for polyterpenol have been identified. Flexibility, tunable permittivity and loss tangent properties of polyterpenol suggest the material can be used as an insulating layer in plastic electronics. Implementation of polyterpenol as a surface modification of the gate insulator in pentacene-based Field Effect Transistor resulted in significant improvements, shifting the threshold voltage from + 20 V to –3 V, enhancing the effective mobility from 0.012 to 0.021 cm²/Vs, and improving the switching property of the device from 10⁷ to 10⁴. Polyterpenol was demonstrated to have a hole transport electron blocking property, with potential applications in many organic devices, such as organic light emitting diodes. Encapsulation of biomedical devices is also proposed, given that under favourable conditions, the original chemical and biological functionality of terpinen−4−ol molecule can be preserved. Films deposited at low RF power were shown to successfully prevent adhesion and retention of several important human pathogens, including P. aeruginosa, S. aureus, and S. epidermidis, whereas films deposited at higher RF power promoted bacterial cell adhesion and biofilm formation. Preliminary investigations into in vitro biocompatibility of polyterpenol demonstrated the coating to be non−toxic for several types of eukaryotic cells, including Balb/c mice macrophage and human monocyte type (HTP−1 non-adherent) cells. Applied to magnesium substrates, polyterpenol encapsulating layer significantly slowed down in vitro biodegradation of the metal, thus increasing the viability and growth of HTP−1 cells. Recently, applied to varied nanostructured titanium surfaces, polyterpenol thin films successfully reduced attachment, growth, and viability of P. aeruginosa and S. aureus.

Seizure resistance of cast aluminium alleys containing dispersed graphite particles of differing sizes

The seizure resistance of cast graphite-aluminium composite alloys containing graphite particles of various sizes was studied using a Hohman wear tester. If the graphite content is more than 2% these alloys can be selfmated without seizure under conditions of boundary lubrication. The size and shape of the graphite particles had no significant effect on seizure resistance. Owing to the extensive deformation and fragmentation of graphite, the low yield strength of the aluminium matrix and the low flow stress of the graphite particles, a continuous layer of graphite is formed on the mating surfaces even after a short running-in period. This layer persisted even after extensive wear deformation.

Trends in US contact lens prescribing 2002-2014

Purpose To document contact lens prescribing patterns in the United States between 2002 and 2014. Methods A survey of contact lens prescribing trends was conducted each year between 2002 and 2014, inclusive. Randomly selected contact lens practitioners were asked to provide information relating to 10 consecutive contact lens fits between January and March each year. Results Over the 13-year survey period, 1650 survey forms were received from US practitioners representing details of 7702 contact lens fits. The mean (±SD) age of lens wearers was 33.6 (±15.2) years, of whom 65.2% were female. Rigid lens new fits decreased from 13.0% in 2002 to 9.4% in 2014. Across this period, silicone hydrogels have replaced mid water contact lens hydrogels as the soft lens material of choice. Toric lenses represented about 25 to 30% of all soft lens fits. Multifocal soft lenses are generally preferred to monovision. Daily disposable lens fits have recently increased, and in 2014, they represented 27.1% of all soft lens fits. Most lenses are prescribed on 1 to 2 weekly or monthly lens replacement regimen. Extended wear remains a minority lens wearing modality. The vast majority of those wearing reusable lenses use multipurpose lens care solutions. Lenses are mostly worn 7 d/wk. Conclusions This survey has revealed prescribing trends and preferences in the United States over the past 13 years.

Mechanism of improvement in oil spreadability of aluminium alloy-graphite particle composites

The spreadability of SAE-30 oil on Al-12 Si base (LM-13) alloy containing dispersed graphite particles about 50 μm average size in its matrix is found to be greater than on either LM-13 with no graphite or brass. It is also found that the spreadability on LM-13 base alloys increase with increasing volume of graphite dispersion in the matrix of these alloys. Further increases in the spreadability of oil on machined LM-13-graphite particle composite test surfaces occur if these are rubbed initially against control discs of either LM-13 or grey cast iron. The formation of a triboinduced graphite-rich layer, confirmed by esca, appears to be responsible for the improved oil spreadability on the rubbed test surfaces of LM-13 base alloys as compared to the as-machined test surfaces prior to rubbing. The triboinduced layer of graphite is apparently responsible for the observed reduction in the friction, wear and seizing tendency of triboelements made from aluminium alloy-graphite particle composites.

Physical characterization of plastic surfaces in wearing and cleanability research

Plastic surfaces are a group of materials used for many purposes. The present study was focused on methods for investigation of surface topography, wearing and cleanability of polyvinyl chloride (PVC) model surfaces and industrial plastic surfaces. Contact profilometry, scanning electron microscopy (SEM) and atomic force microscopy (AFM) are powerful methods for studying the topography of plastic surfaces. Although they have their own limitations, they are together an effective tool providing useful information on surface topography, especially when studying laboratory-made PVC model surfaces with known chemical compositions and structures. All examined laboratory-made PVC plastic surfaces examined in this work could be considered as smooth according to both AFM and profilometer measurements because height differences are in the nanoscale on every surface. Industrial plastic surfaces are a complex group of materials because of their chemical and topographical heterogeneity, but they are nevertheless important reference materials when developing cleaning and wearing methods. According to the results of this study the Soiling and Wearing Drum and the Frick-Taber methods are very useful when simulating three-body wearing of plastic surfaces. Both the investigated wearing methods can be used to compare the wearing of different plastic materials using appropriate evaluation methods of wearing and industrial use. In this study, physical methods were developed and adapted from other fields of material research to cleanability studies. The thesis focuses on the methodology for investigating the cleanability of plastic surfaces under realistic conditions, where surface topography and the effect of wear cleanability were among the major topics. A colorimetric method proved to be suitable for examining the cleanability of the industrial plastic surfaces. The results were utilized to evaluate the relationship between cleanability and the surface properties of plastic surfaces. The devices and methods used in the work can be utilized both in material research and product development.

The validity of the GENEActiv wrist-worn accelerometer for measuring adult sedentary time in free living

OBJECTIVES Based on self-reported measures, sedentary time has been associated with chronic disease and mortality. This study examined the validity of the wrist-worn GENEactiv accelerometer for measuring sedentary time (i.e. sitting and lying) by posture classification, during waking hours in free living adults. DESIGN Fifty-seven participants (age=18-55 years 52% male) were recruited using convenience sampling from a large metropolitan Australian university. METHODS Participants wore a GENEActiv accelerometer on their non-dominant wrist and an activPAL device attached to their right thigh for 24-h (00:00 to 23:59:59). Pearson's Correlation Coefficient was used to examine the convergent validity of the GENEActiv and the activPAL for estimating total sedentary time during waking hours. Agreement was illustrated using Bland and Altman plots, and intra-individual agreement for posture was assessed with the Kappa statistic. RESULTS Estimates of average total sedentary time over 24-h were 623 (SD 103) min/day from the GENEActiv, and 626 (SD 123) min/day from the activPAL, with an Intraclass Correlation Coefficient of 0.80 (95% confidence intervals 0.68-0.88). Bland and Altman plots showed slight underestimation of mean total sedentary time for GENEActiv relative to activPAL (mean difference: -3.44min/day), with moderate limits of agreement (-144 to 137min/day). Mean Kappa for posture was 0.53 (SD 0.12), indicating moderate agreement for this sample at the individual level. CONCLUSIONS The estimation of sedentary time by posture classification of the wrist-worn GENEActiv accelerometer was comparable to the activPAL. The GENEActiv may provide an alternative, easy to wear device based measure for descriptive estimates of sedentary time in population samples

Surface treatments for pistons and their effect on engine performance

Surface treatment alters the frictional behaviour of pistons in I.C. engines and can be used to improve engine performance. Surface treatments applied to aluminium alloy pistons of a high speed diesel engine and their effect on the engine performance are described. Certain piston surface treatments improve engine performance and also reduce the run-in period.

Analysis and computation of the oil film thickness between the piston ring and cylinder liner of an internal combustion engine

A study of the essential features of piston rings in the cylinder liner of an internal combustion engine reveals that the lubrication problem posed by it is basically that of a slider bearing. According to steady-flow-hydrodynamics, viz. Image the oil film thickness becomes zero at the dead centre positions as the velocity, U = 0. In practice, however, such a phenomenon cannot be supported by consideration of the wear rates of pistion rings and cylinder liners. This can be explained by including the “squeeze” action term in the