Modelling of Moisture Movement in Wood during Outdoor Storage

A model of moisture movement in wood is presented in this paper in a two-dimensional-in-space formulation. The finite-difference technique has been used in order to obtain the solution of the problem. The model was applied to predict the moisture content in sawn boards from pine during long term storage under outdoor climatic conditions. The satisfactory agreement between the numerical solution and experimental data was obtained.

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One-dimensional Droplet Model for Prediction of Jet-tip Height of Subcooling Mixing Jet for Cryogenic Propellant Storage Tank

10.21203/rs.3.rs-929364/v1 ◽

2021 ◽

Author(s):

Osamu Kawanami ◽

Kentaro Takeda ◽

Ryoki Matsushima ◽

Ryoji Imai ◽

Yutaka Umemura ◽

...

Keyword(s):

Experimental Data ◽

Storage Tank ◽

Thermal Stratification ◽

Droplet Model ◽

Spherical Droplet ◽

One Dimensional ◽

Long Term Storage ◽

Proposed Model ◽

Term Storage

Abstract This study proposes a one-dimensional droplet model to predict the jet-tip height of a subcooling mixing jet issuing from the bottom of a cryogenic propellant storage tank. Cryogenic liquids, such as liquid hydrogen and liquid oxygen, are used as propellants and oxidants in spacecraft propulsion systems that require long-term storage in a closed tank. However, thermal stratification forms near the gas-liquid interface during long-term storage of cryogens due to heat flowing into the tank from the surrounding environment. In addition, boil-off gas (BOG) is generated from the interface, which causes increased pressure in the tank. To reduce the BOG, it is effective to destroy the thermal stratification by mixing in the cold jet issuing from the bottom of the tank. Ground experiments using FC-72 and water as test fluids are conducted to investigate the behavior of the jet using the proposed one-dimensional spherical droplet model as the tip of the jet. The jet behavior is visualized using the Shadowgraph system and the height of the jet-tip is investigated under various experimental conditions. The proposed model is also verified by comparison with experimental data available in the literature. The results show that the proposed model aligns well with the experimental data.

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Investigation of the chemical composition of pumpkin pulp as a basis for soft drinks

Vestnik MGTU ◽

10.21443/1560-9278-2021-24-4-441-449 ◽

2021 ◽

Vol 24 (4) ◽

pp. 441-449

Author(s):

M. N. Shkolnikova ◽

V. N. Abbazova

Keyword(s):

Sugar Content ◽

Meat Products ◽

Climatic Conditions ◽

Raw Material ◽

Long Term Storage ◽

Technological Potential ◽

Wide Range ◽

Snack Products ◽

Term Storage

Pumpkin fruits ( Cucurbita spp.) have a number of advantages and high technological potential, thanks to almost universal cultivation in a wide range of agro-climatic conditions, the ability to long-term storage, the content of dietary fibers, pectin and other polysaccharides, carotenoids, polyphenolic substances, vitamins, which cause a wide range of physiological orientation. In the process of researching the composition of local cultivars of pumpkin and the world experience of using Cucurbita spp. in the composition of food products, the need to use this ingredient in beverage recipes has been substantiated. The content of dry substances in the pumpkin samples is from 8.18 % ("Gribovskaya") to 11.6 % ("Orange bush"). The maximum sugar content is distinguished by the varieties "Winter Sweet" (6.87 %) and "Orange Bush" (7.40 %). The content of BAS-antioxidants is (without visible difference depending on the growing region): carotenoids from 1.3 mg/100 g in "Gribovskaya" to 2.0 mg/100 g - "Orange bush"; ascorbic acid - 8.7 mg/100 g in "Rossiyanka" to 14.2 mg/100 g - "Orange bush". Today all parts of the pumpkin fruit are used: the bark is a raw material for the production of feed flour and a substrate for the cultivation of lactobacilli, the seeds are traditionally used to produce pumpkin oil and flour, the pulp of the fruit is a raw material for juice-containing products, purees, carotenoid-containing and polysaccharide extracts, pectin, concentrates of first and second dishes, snack products, pasta, bakery, confectionery and meat products, etc.

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Numerical calculation of internal wave motions

Journal of Fluid Mechanics ◽

10.1017/s002211207200285x ◽

1972 ◽

Vol 56 (2) ◽

pp. 265-276 ◽

Cited By ~ 23

Author(s):

James A. Young ◽

C. W. Hirt

Keyword(s):

Experimental Data ◽

Numerical Calculation ◽

Finite Difference ◽

Incompressible Fluid ◽

Internal Wave ◽

Fluid Flows ◽

Two Dimensional ◽

Finite Difference Technique ◽

Small Density ◽

Incompressible Fluid Flows

A finite-difference technique for the numerical calculation of two-dimensional stratified incompressible fluid flows is presented. Small density variations are not assumed, so that this method is generally applicable to a wide variety of problems. To illustrate this new technique a calculation has been made of the collapse of a uniformly mixed region in a linearly stratified fluid. In addition to giving excellent agreement with experimental data, the calculations also reveal the mechanism for an observed change in scaling behaviour.

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