New high-silicon zeolites of the TsVN series

Translated from Khimiya i Tekhnoloyiya Topliv i Masel, No. 3, pp. 3–5, March, 1989.     

Protoporphyrin-IX as a Substitute for Nitrite in Cured-Meat Color Production

The iron-free heme derivative protoporphyrin-IX, was added to a cooked emulsified beef product to mimic the typical cured-color obtained with nitrite. Although the pigment was stable and could be recovered from the emulsion it imparted a purple hue as noted by visual observation and Hunterlab color values (L,a,b). The possible implications of this pigment as a meat colorant are discussed.     

The development of a stress analysis code for nuclear graphite components in gas-cooled reactors

Most of the UK nuclear power reactors are gas-cooled and graphite moderated. As well as acting as a moderator the graphite also acts as a structural component providing channels for the coolant gas and control rods. For this reason the structural integrity assessments of nuclear graphite components is an essential element of reactor design. In order to perform graphite component stress analysis, the definition of the constitutive equation relating stress and strain for irradiated graphite is required. Apart from the usual elastic and thermal strains, irradiated graphite components are subject to additional strains due to fast neutron irradiation and radiolytic oxidation. In this paper a material model for nuclear graphite is presented along with an example of a stress analysis of a nuclear graphite moderator brick subject to both fast neutron irradiation and radiolytic oxidation.     

Characterization of an ASIC for CPG sensors with grid-only depth of interaction sensing

A new version of the front-end application specific integrated circuit (ASIC) for co-planar-grid (CPG) sensors is presented. Compared to the first version, the ASIC is optimized for signal/noise performance, modified in peaking time, and it implements timing signals to measure the depth of interaction using the grids signals only. Experimental results using state-of the-art CPG sensors and different approaches for reducing the error due to electron trapping are reported. A new technique that makes use of the sum and difference of the grids signals is also presented.     

Change in computer hardware and software paradigms

The change in the paradigm of the development of processors and software for the processors is considered. This change is caused by the continuous progress in the technology of semiconductor microchips that is described by Moore’s law.     

Phase Shifter for a 915 MHz Phased Array Hyperthermia System

This paper describes a design for an analog phase shifter operating at 915 MHz and suitable for use in a phased array microwave hyperthermia system. Here, the major operating constraint was minimization of amplitude variation over a 1800 phase shift, whereas previous phase shifters were designed to obtain a linear relationship between phase and control voltage. The result is a simple, inexpensive hybrid coupler phase shifter that operates over a narrow bandwidth and provides 180°of continuous phase shift with input powers up to 1 W.     

Detection of Heat-Resistant Proteases Produced by Psychrotrophs in Refrigerated Milk

Proteases from four species of Pseudomonas were added to pasteurized milk at .18, 1.8, and 18 units of protease activity per milliliter followed by incubation at 5 C for 18 days. During this period milks were analyzed every 2 days for proteolysis by methods of Hull, ninhydrin, and absorption at 280 nm. Sensory analysis was done twice weekly for 18 days. There were no significant differences noted for protease activity when ninhydrin and absorption at 280 nm were used; however, only 18 units protease/ml were detected by the Hull test. Sensory evaluation correlated with the Hull test data. When 50 and 500 cells/ml were added to milk, a curvilinear increase in proteolysis was noted by 11 and 13 days, respectively, for three of the four Pseudomonas species as detected by the Hull method. Heat inactivation of the proteases at 62.8°C for 30 min was 0 to 73.1% and 10 to 36% as measured by the Hull and agar diffusion methods, respectively.     

Nutritional epidemiology

Epidemiological techniques constitute an important method of nutritional investigation. Historical and geographical evidence suggests hypotheses which can be tested by more detailed studies. Cross-sectional surveys describe populations and provide information about prevalence; they also enable the interrelationships of various nutritional and physiological indices to be investigated. The case-control study is useful in exploring possible aetiological factors in diseases, but has the drawback that past dietary information is difficult to obtain accurately. Prospective studies identify predictors of disease and death; they are especially valuable in elucidating the natural history of disease, and supply good evidence on causation, but their duration and expense are disincentives to their use. Randomized controlled trials provide the most precise evidence about causation, and should be used whenever feasible to answer specific questions.