Control of strain aging in alpha-iron

The principles of strain aging are described in terms of the Cottrell theory. It is deduced that the practical control of strain aging must come through control of the effective amounts of carbon and nitrogen in solution. Existing control methods such as precipitation through alloying or heat treatment are reviewed and their deficiencies described. Experimental results for a series of alloys containing carbon and nitrogen show that only carbon strain aging can be eliminated by heat treatment. The use of titanium, aluminum, vanadium, and boron as alloying elements for the control of nitrogen strain aging is examined. All of these elements are effective but for economic reasons boron additions appear to offer the most promising practical solution to the problem of nitrogen strain aging in steels.     

New Kerr cell for low-temperature measurements

A Kerr cell has been constructed which can be used to study the Kerr effect in liquids from room temperature down to 77 K. At low temperatures, the cell windows are free of moisture. The cell has been tested and measurements on liquid carbon disulfide, between 170 and 300 K, are discussed.     

Distributional impacts of the North Dakota gas flaring policy

This paper considers whether the reform of North Dakota’s natural gas flaring policy provided large operators a competitive advantage, leading to increased market concentration. North Dakota was the highest gas flaring and venting state in USA until it was taken over by Texas in 2015 coinciding with the implementation of its gas flaring policy in 2014. Two analyses are performed in North Dakota (and Wyoming, as a control) to compare the effect that the flaring policy had on the state’s oil sector. The analyses show mixed evidence, larger firms gained an advantage leading to fewer smaller firms operating in the state. The paper concludes with highlighting possible further areas for research, and methodologies for acquiring more reliable data.     

Cumulative plastic deformation observed during cyclic testing in rolling ball-cylinder and static ball-flat plate experiments

The plastic deformation accompanying rolling contact and static ballflat plate fatigue tests is described for identical experimental conditions. In particular, the problem of whether or not cumulative plastic deformation accompanies repeated Brinell indentations is investigated. The occurrence of cumulative plastic deformation seems, in part, to be determined by the frequency of loading.     

The dufour gland and the secretion placed on eggs of two species of social wasps,Liostenogaster flavolineata andParischnogaster jacobsoni (vespidae: Stenogastrinae)

The secretion placed on eggs and fed to larvae and the ant guard placed on the nest stalk ofParischnogaster jacobsoni contain the same hydrocarbons and in approximately the same proportions as is found in the Dufour gland. The secretion on eggs is a mixture of the contents of the Dufour gland and nectar. The emulsifying agent is a palmitic acid salt. Similarly, inLiostenogaster flavolineata, the egg secretion is an emulsion of nectar and Dufour gland secretion, which contains alkoxyethanol emulsifiers, found in nature for the first time.     

Software for 3-D visualization/analysis of optic-disc images

Discusses a software tool called the stereo optic disc analyzer (SODA) (patent pending ID:P09819, 1997), which has been developed for quantitative image processing of stereo optic-disc photographs to aid in the diagnosis and assessment of retinal disease. It is able to perform color matching and alignment of two images so that they are superimposed and viewed in 3-D sequential display by use of a pair of 3-D goggles. These 3-D images of the same patient are taken at different times, often over periods of several years. Measurements of optic-disc cupping, vertical and horizontal cup/disc ratio, cup and disc area, diameter, shape, and neuroretinal rim width can be determined using a predefined template placed over the image (one for the right eye and one for the left eye). Sequential display of stereo images (stereo flicker chronoscopy) and digital stereophotogrammetry provide sensitive methods for monitoring glaucomatous changes to the optic disc     

Trends in the use of silicone hydrogel contact lenses for daily wear

Although the first silicone hydrogel contact lenses introduced onto the world contact lens market in 1999 held approval for both daily wear and extended wear use, the latter modality was promoted much more heavily by the manufacturers. The first silicone hydrogel lenses specifically promoted for daily wear were introduced in 2003. Data that we have gathered from annual contact lens fitting surveys demonstrate an immediate increase in market share whereby this lens type now represents more than one-third of soft lens fits in the United Kingdom. The success of this lens category is attributed to the health and safety benefits of silicone hydrogel materials and the positive impact of lens manufacturers by way of the effective marketing and distribution of these products.     

Prescribing daily disposable contact lenses in the UK.

Patterns of prescribing daily disposable contact lenses in the UK were determined by mining through data gathered from annual contact lens fitting surveys conducted over the past 12 years. Spherical, toric and multifocal design daily disposable lenses represent a substantial proportion of all contact lenses prescribed, reflecting the significant ocular health and lifestyle advantages offered by this lens category.     

Effect of thermosonication,pulsed electric field and their combination on inactivation of Listeria innocua in milk

The impact of thermosonication (TS) and pulsed electric field (PEF), individually and combined, on the survival of Listeria innocua 11288 (NCTC) in milk was investigated. TS (400 W, 160 s) without pre-heating reduced L. innocua by 1.2 log₁₀ cfu mL^?1, while shorter treatment times produced negligible inactivation, suggesting TS to be a hurdle rather than an effective standalone treatment. PEF (30 and 40 kV cm^?1, 50 μs) at 10 °C caused a reduction of L. innocua of 1.1 and 3.3 log cycles, respectively. The highest field strength (40 kV cm^?1) combined with TS (80 s) led to 6.8 log₁₀ cfu mL^?1 inactivation. Milk pre-heated to 55 °C (over 60 s) prior to TS followed by PEF (30 and 40 kV cm^?1) showed inactivation between 4.5 and 6.9 log₁₀ cfu mL^?1, the latter being comparable (P > 0.05) with thermal pasteurisation. The data indicate that TS followed by PEF represents a valid alternative for L. innocua inactivation in milk.     

Inactivation of Escherichia coli in a Tropical Fruit Smoothie by a Combination of Heat and Pulsed Electric Fields

ABSTRACT: Moderate heat in combination with pulsed electric fields (PEF) was investigated as a potential alternative to thermal pasteurization of a tropical fruit smoothie based on pineapple, banana, and coconut milk, inoculated with Escherichia coli K12. The smoothie was heated from 25 °C to either 45 or 55 °C over 60 s and subsequently cooled to 10 °C. PEF was applied at electric field strengths of 24 and 34 kV/cm with specific energy inputs of 350, 500, and 650 kJ/L. Both processing technologies were combined using heat (45 or 55 °C) and the most effective set of PEF conditions. Bacterial inactivation was estimated on standard and NaCl‐supplemented tryptone soy agar (TSA) to enumerate sublethally injured cells. By increasing the temperature from 45 to 55 °C, a higher reduction in E. coli numbers (1 compared with 1.7 log₁₀ colony forming units {CFU} per milliliter, P < 0.05) was achieved. Similarly, as the field strength was increased during stand‐alone PEF treatment from 24 to 34 kV/cm, a greater number of E. coli cells were inactivated (2.8 compared with 4.2 log₁₀ CFU/mL, P < 0.05). An increase in heating temperature from 45 to 55 °C during a combined heat/PEF hurdle approach induced a higher inactivation (5.1 compared with 6.9 log₁₀ CFU/mL, respectively {P < 0.05}) with the latter value comparable to the bacterial reduction of 6.3 log₁₀ CFU/mL (P≥ 0.05) achieved by thermal pasteurization (72 °C, 15 s). A reversed hurdle processing sequence did not affect bacterial inactivation (P≥ 0.05). No differences were observed (P≥ 0.05) between the bacterial counts estimated on nonselective and selective TSA, suggesting that sublethal cell injury did not occur during single PEF treatments or combined heat/PEF treatments.