Background. Chufa is one of the most promising rare oilseed crops. The issues of preserving and obtaining highquality seed material are very important. The development of long-term genebank storage techniques for chufa nodules is a pressing task.Materials and methods. We studied 18 chufa germplasm accessions of various origin. The field study was conducted in 2010–2012 under the environmental conditions of Krasnodar Territory, Russia. Protein and oil content was analyzed according to the guidelines on the methods of quality control and safety of bioactive food additives (R 4.1.1672-03…, 2004); vitamin E according to the guidelines on the methods of analyzing the quality and safety of food products (Skurikhin, Tutelyan, 1987); fatty acid composition in line with IUPAC (1979) and GOST R 512677-2006, using an IIRGCS chromatograph.Results and conclusions. The study of valuable agronomic characters in chufa accessions showed that the height of plants varied from 49 to 69 cm; the number of nodules per plant from 80 to 110 pcs; the weight of nodules per plant from 18 to 49 g; the weight of nodules per plot (1 m2 ) from 101 to 393 g. Their oil content varied from 13.1 to 21.06 g/100 g, and protein content from 6 to 10%. Chufa accessions contained large amount of vitamin E: 19.23 to 35.23 mg/100 g. The content of saturated fatty acids in chufa oil was 17.75 to 20.99%, monounsaturated fatty acids from 68.21 to 71.55%, and polyunsaturated fatty acids from 9.94 to 12.17%. A technique of preparing chufa nodules for long-term storage was developed. The optimal time to assess germination energy is four days, with 11 days for germination percentage. Storage of chufa nodules for three years at a temperature of +20°C causes a decrease in their germination by 15–16%. When stored under low positive (+4°C) or negative temperatures (–18°C and –196°C), their germination percentage remained unchanged.

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It is shown that the problem of determining the type and parameters of conduit end fastening from the eigenfrequency spectrum has a dual solution. A method of solving this problem is developed. Some examples are given. Introduction.Conduits are important elements of the fuel systems of cars, tractors, ships, planes, etc. Their vibrations often cause drumming, leading to discomfort for crew members and passengers. This is due to the fact that the frequency spectra of conduit vibrations are sometimes in a range hazardous to human health. To change the conduit vibration frequencies, it is not always reasonable to change the conduit length or attach concentrated masses. Therefore, to produce comfort conditions for passengers, it is required to determine the types of conduit fastening that provide the necessary (safe) range of conduit vibration frequencies. This refers not only to the fundamental vibration mode but also overtones. This problem is related to issues of noise suppression [1-3], acoustic diagnostics, [4][5][6][7][8][9] and the theory of inverse problems of mathematical physics [10,11].The goal of the present work was to determine the fastening parameters of a conduit filled with a fluid from the eigenfrequencies of its flexural vibrations. The problems of diagnosing the fastening of strings, membranes, and plates have been studied previously [12][13][14][15][16][17][18][19]. For conduits, however, the problem formulated here is apparently considered for the first time. In addition, unlike in [12][13][14][15][16][17][18][19], in the present work, four rather than two boundary conditions are sought, which significantly complicates the problem and requires the use of different methods for its solution.Problems of calculating the eigenfrequencies of flexural vibrations of conduits were investigated in [20,21]. However, the inverse problem -determining the boundary conditions from eigenfrequencies -was not studied in these papers. In addition, in [20,21], only approximate methods (for example, the Galerkin and Rayleigh-Ritz methods) were considered, which are unsuitable for the solution of the problem formulated.1. Primal Problem. The small free vibrations of a conduit filled with a fluid (which is incompressible) is described by the following equation [20] (see also [21, pp. 193-196]):

В России в связи с возрастающими объемами сплошных вырубок лесов, природными катаклизмами и снижающегося биоразнообразия все большее значение приобретает сохранение генетических лесных ресурсов ex-situ в генетических банках в виде семян. Однако до сих пор не создан банк семян основных лесообразующих пород. В 2011 г. начат долгосрочный опыт по хранению семян сосны обыкновенной (Рinus sylvestris L.) и ели европейской (Picea abies (L.) Karst.) при различных температурных режимах: +20, +4, –18 и –182 °С (пары жидкого азота). В настоящей работе представлены первые результаты 3-летнего хранения партий семян, различающихся сроками заготовки (1996–2011 гг.) и, соответственно, исходным качеством семян. При хранении семян, предварительно подсушенных до влажности 4,2–4,4%, обнаружено явное преимущество отрицательных температур по сравнению с положительными. Наибольшее снижение всхожести наблюдалось у семян, хранившихся при +20 °С: на 7–64% у семян ели и на 20–30% у семян сосны. Хранение семян при +4 °C приводило к снижению всхожести только в партиях самых давних сроков сбора. При температурах –18 и –182 °С всхожесть оставалась на исходном уровне практически во всех партиях семян, в отдельных случаях наблюдалось некоторое повышение всхожести. По ряду более чувствительных показателей (энергия прорастания и сила роста), а также степени распространения микрофлоры обнаружено некоторое преимущество криоконсервации по сравнению с неглубоким замораживанием (–18 °C). Предполагается, что с увеличением периода хранения эта разница будет более заметной. Таким образом, исходные посевные качества семян, их влажность и температура являются важными факторами их успешного хранения. Для свежезаготовленных семян сосны и ели допустимо кратковременное (в течение 2–3 лет) хранение при температуре +4 °С. Температуру –18 °C можно рекомендовать для хранения семян в течение более продолжительного периода времени (более 5 лет). Криоконсервация семян представляется наиболее перспективным режимом долговременного хранения генофонда хвойных растений.

We consider the inverse problem of finding the relative rigidity of elastic edge edges of a cylindrical shell that is inaccessible to visual inspection, by two natural frequencies of its axisymmetric vibrations. A theorem on the duality of the solution of this inverse problem is proved. The corresponding counterexamples are given.