Results 1 - 10 of 79
Results 1 - 10 of 79. Search took: 0.022 seconds
|Sort by: date | relevance|
[en] This paper presents the basic problems relating to food preservation in developing countries as well as outlining the relative importance of these problems among the whole group of basic socio-economic problems of the world today. Statistics are presented (using the USA as an example of a well-developed country) on the importance of technology in the production and preservation of foods. The food preservation problems of the developing countries are outlined in a general manner with specific illustrations of the problems themselves and the magnitude of these problems. These data are presented in such a manner as to be consistent with the topic of the panel itself. (author). 4 refs, 5 tabs
[en] Radioisotopic tracers are frequently used in hydrological investigations. This manual provides recommendations on safety measures to be used in these investigations. The annexes provide lists of radioisotopic techniques that have been employed together with an indication of the quantities of isotopes used.
[en] The influence of irradiation on the extension of shelf-life of boiled Chub mackerel stored at room temperature (25-300C) was investigated. It was found that boiled Chub mackerel irradiated at 0.1, 0.2, or 0.3 Mrad could be kept with good organoleptic properties at room temperature for 5, 8, and 11 days respectively; while the unirradiated sample could be kept for only 2 days. Boiled Chub mackerel used in this study was found to be heavily contaminated with microorganisms. Irradiation at doses mentioned caused reduction of more than 99% of bacteria. Bacillus and Acinetobacter were found to predominate in the irradiated boiled mackerel. The predominant flora in unirradiated boiled mackerel included Micrococcus, Staphylococcus, Bacillus, Acinetobacter, and Proteus. E. coli was always detected in unirradiated samples and was occasionally detected only in samples irradiated at 0.1 Mrad. Trimethylamine nitrogen (TMA-N) content, total volatile basic nitrogen (TVB-N) content, and total bacterial count (TBC) were used as indices of decomposition of both irradiated and unirradiated samples. TMA-N and TBC were found to be good indices of quality of only unirradiated boiled Chub mackerel, whereas TVB-N was found to be a good index of quality of both irradiated and unirradiated samples
[en] Most of the different theories explaining the mechanism of ion transfer are based on convincing experimental grounds and thus represent comprehensive and self-consistent concepts. They are, though divergent, not contradictory views, although sometimes they have been enunciated disregarding the conclusions from findings of other workers. 87 refs, 5 figs
[en] The objectives of this project in food irradiation are two-fold, to study the effect of irradiation in prolongation of useful storage life of fruits and to evaluate irradiation as a means of preserving fruits. However radiation is not intended to replace existing preservation processes but may be used in conjunction with current methods such as refrigeration, drying, fermentation etc. In fact radiation should combine with proper storage and packaging techniques in order to ensure maximum benefits. Ripening retardation of fruits by irradiation kinds of fruits: papaya, mango, rambutan, longan and durian. Changes in organoleptic properties of fruit flavor and taste, texture changes by taste panel estimation of significance level of results by statistical mathematical methods, chemical changes determination of climacteric peak in fruits by estimation of carbon dioxide evolution, vitamin C determination by Tillmann's method, carotenoid separation by thin layer chromatography, reducing sugars and acidity determination, volatile components of durian by gas-chromatography
[en] Very general models can be proposed for relating the surviving proportion of an irradiated population of cells or bacteria to the absorbed dose, but if the number of free parameters is large the model can never be tested experimentally (Zimmer; Zirkie; Tobias). A relatively simple model is therefore proposed here, based on the physical facts of energy deposition in small volumes which are currently under active investigation (Rossi), and on cell-survival experiments over a wide range of LET (e.g. Barendsen et al.; Barendsen). It is not suggested that the model is correct or final, but only that its shortcomings should be demonstrated by comparison with experimental results before more complicated models are worth pursuing. It is basically a multihit model applied first to a single target volume, but also applicable to the situation where only one out of many potential target volumes has to be inactivated to kill the organism. It can be extended to two or more target volumes if necessary. Emphasis is placed upon the amount of energy locally deposited in certain sensitive volumes called 'target volumes'
[en] The problem of conserving dried and smoked fish. Fresh water fisheries are one of the major sources of protein in Africa. More than 100,000 t of fish are believed to be caught commercially in the Niger basin and 150,000 t in that of the Chad. These dried or smoked fish are then exported throughout Black Africa. Through attack by parasitic insects more than 30 wt.% of the fish are destroyed. None of the conventional methods of combating these insects has so far produced any practical results. There have been several radiation experiments carried out to date. A series of irradiation experiments has been carried out in France with doses of 20,000, 100,000, 500,000 rad. The order of magnitude of lethal and sterilizing doses has been determined without any organoleptic change being observed at 500,000 rad. There are studies which are still necessary. These comprise eontomological studies, determination of practical dose, studies on nutritional value, research into packaging techniques, and economic analysis. These studies are not extensive if one leaves aside the problems of wholesomeness and edibility (for which, incidentally, very favourable results have already been obtained with fish subjected to doses well above the 15,000 to 40,000 rad which would probably be necessary in this case). The proposals for organizing research include preliminary studies which might be carried out either in Africa or Europe and technical development which would certainly necessitate the construction of a pilot plant in Africa. An economic study shows that for an increase of the order of 1% in the price of the product one can expect to eliminate losses amounting to several tens of per cent. (author). 1 tab
[en] Most important properties of soil as a shielding material were analysed. Gamma radiation absorption coefficient for soil was measured under laboratory conditions. Shielding potential of soil was measured under natural conditions as well. Comparison of shielding potentials of soil and ordinary concrete (density = 2.35 g/cm3), showed that 1 m thick layer of soil is equivalent to 70 cm thick layer of concrete for absorption of gamma radiation from Co-60 (mean energy = 1.25 MeV). The obtained results are needed for estimation of shielding potential of soil layers
[sr]Analizirane su osnovne karakteristike zemlje kao materijala za zastitu od gama zracenja. Eksperimentalno je odredjivan koeficijenat apsorpcije gama zracenja za zemlju u laboratorijskim uslovirna. Takodje je merena zastitna moc zemlje u prirodnim uslovima. Poredjenjem zastitne moci zemlje sa zastitnom moci obicnog betona, gustine 2,35 gr/cm3, pokazano je da je sloj zemlje debljine 1 m, u pogledu apsorpcije gama zracenja Co-60 (srednja energija - 1,25 MeV-a), ekvivalentan sloju betona debljine 70 cm. Dobiveni rezultati neophodni su za procenu zastitne moci slojeva zemlje (author)
[en] Researches have described their observations on the stimulated growth of plants, and higher yields, when they are affected by physiologically active substances or by ionizing radiation at low doses. Others cannot confirm these results, or they find that stimulating effects occur occasionally and only under specific conditions. This paper discusses possible explanations of the different observations. 91 refs, 7 figs
[en] The basic object in the use of protective clothing and equipment is to prevent contamination of the skin and to prevent inhalation and ingestion of radioactive isotopes or other toxic materials. This book is a guide to deciding the kind and quantity of protective equipment needed for a particular type of laboratory or operation.