scholarly journals Scientific Analysis and Conservation of Waterlogged Woods Excavated from Suyoeng-ri Site, Hwaseong, Korea

2021 ◽  
Vol 37 (5) ◽  
pp. 579-589
Author(s):  
Kwang-Hee Lee ◽  
Jeong-Eun Oh ◽  
Soo-Chul Kim
Keyword(s):  
Freeze Drying ◽  
Room Temperature ◽  
Manufacturing Processes ◽  
Drying Method ◽  
Manufacturing Method ◽  
Neolithic Age ◽  
Scientific Analysis ◽  
Morus Spp ◽  
The Neolithic Age ◽  
Shelf Temperature

Five waterlogged wood artefacts were excavated from Suyeong-ri site in Hwaseong, South Korea. The aim of the present study was to identify the species and estimate the date of manufacture and the manufacturing method of these artefacts. The study also aimed to conserve the original shapes of waterlogged wood artefacts by using the vacuum freeze drying method. The two large waterlogged woods were identified as Ulmus spp. and Morus spp., whereas one of the three small waterlogged woods was identified as Abies spp. and the other two as hard pine. Radiocarbon dating using wiggle match dated the manufacturing of these wooden artefacts between BCE 8520-8490 or BCE 8470-8290 in the Neolithic age, and a similar period was also confirmed for seed excavated from a place close to the location where the waterlogged wood artefacts were excavated. The surface of waterlogged wood artefacts had several traces of manufacturing processes - traces of tearing and chopping - were observed. Based on these observations, it was confirmed that stone adz was used to make these wooden artefacts. Thereafter, the waterlogged wood samples were conserved by immersing them into PEG#4,000 of concentration in water from 10% to 40% at room temperature(15~25℃) and subjecting them to vacuum freeze drying. However, the internal moisture was not completely removed in some thick parts of waterlogged woods by applying the general schedule such as raising the shelf temperature as the surface temperature rises. Therefore, additional study is required using the schedule-method for vacuum freeze drying of large waterlogged wood.

scholarly journals Impact of shelf temperature on freeze-drying process and porosity development

2018 ◽  
Author(s):  
M. M. Camacho ◽  
L. A. Egas-Astudillo ◽  
A. Silva ◽  
M. Uscanga ◽  
N. Martínez-Navarrete
Keyword(s):  
Freeze Drying ◽  
Room Temperature ◽  
Gum Arabic ◽  
Drying Kinetics ◽  
Drying Process ◽  
Drying Time ◽  
Lower Porosity ◽  
The Impact ◽  
Shelf Temperature ◽  
Porosity Development

The freeze-drying kinetics and the superficial porosity development of grapefruit puree. The impact of biopolymers addition (gum Arabic and bamboo fiber) and to apply (40 ºC) or not shelf temperature (room temperature) was considered. To increase the shelves temperature during freeze-drying allowed to an important drying time reduction and doesn’t supposed a lower porosity related to the collapse development of the structure. Biopolymers do not affect the drying kinetics. From this results, biopolymers addition and to heat at least up to 40 ºC during grapefruit freeze-drying should be recommended. Keywords: freeze-drying; shelf temperature; drying kinetics; image analysis; pore size distribution.

scholarly journals Ferromagnetic properties of ZnO:Mn nanocrystals obtained by the freeze-drying method

2020 ◽  
Vol 28 (1) ◽  
pp. 55-60
Author(s):  
O. V. Kovalenko ◽  
V. Yu. Vorovsky ◽  
O. V. Khmelenko ◽  
Ye. G. Plakhtii ◽  
O. I. Kushnerov
Keyword(s):  
Freeze Drying ◽  
Room Temperature ◽  
Hexagonal Lattice ◽  
Drying Method ◽  
Ferromagnetic Properties ◽  
Spintronic Devices ◽  
Broad Absorption Line ◽  
Destructive Action ◽  
Pure Phase ◽  
Impurity Defects

In the work, the nanocrystals ZnO and ZnO:Mn with a concentration of Mn 2 and 4 at.% were obtained by the low-temperature freeze-drying method. For this purpose, solutions of zinc acetate Zn(CH3COO)2∙2H2O and manganese one Mn(CH3COO)2∙4H2O were used. By means of XRD, it is established that nanocrystals (NC’s) have a pure phase and wurtzite-type hexagonal lattice, their size is d ~ 65 nm. The EPR spectra of the samples have a broad absorption line. It is due to the presence of a large number of intrinsic and impurity defects in the NC’s. These defects are the result of the destructive action of hydrogen, which is a product of the thermal decomposition of zinc and manganese acetates. It is shown that there is a relationship between the number of crystal lattice defects in the ZnO:Mn NC’s and their ferromagnetic properties at room temperature. Samples of ZnO:Mn with a concentration of Mn 2 and 4 at.%. have a specific magnetization value of Мs equal to 0.089 and 0.045 emu/g, respectively. The results can have great potential in spintronic devices and spin-based electronics.

Scanning Electron Microscopy-cuticular Lesions on the Roundworm Ascaris Suum

1970 ◽  
Vol 28 ◽  
pp. 114-115
Author(s):  
P. A. Madden ◽  
W. R. Anderson
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Freeze Drying ◽  
Room Temperature ◽  
Secondary Electron ◽  
Distilled Water ◽  
Freeze Dried ◽  
Silver Paint ◽  
To Come ◽  
Scanning Electron

The intestinal roundworm of swine is pinkish in color and about the diameter of a lead pencil. Adult worms, taken from parasitized swine, frequently were observed with macroscopic lesions on their cuticule. Those possessing such lesions were rinsed in distilled water, and cylindrical segments of the affected areas were removed. Some of the segments were fixed in buffered formalin before freeze-drying; others were freeze-dried immediately. Initially, specimens were quenched in liquid freon followed by immersion in liquid nitrogen. They were then placed in ampuoles in a freezer at −45C and sublimated by vacuum until dry. After the specimens appeared dry, the freezer was allowed to come to room temperature slowly while the vacuum was maintained. The dried specimens were attached to metal pegs with conductive silver paint and placed in a vacuum evaporator on a rotating tilting stage. They were then coated by evaporating an alloy of 20% palladium and 80% gold to a thickness of approximately 300 A°. The specimens were examined by secondary electron emmission in a scanning electron microscope.

High-Resolution Scanning Electron Microscopy of Biological Specimens

1988 ◽  
Vol 46 ◽  
pp. 186-187
Author(s):  
M. Müller ◽  
R. Hermann
Keyword(s):  
High Resolution ◽  
Freeze Drying ◽  
Room Temperature ◽  
Structural Information ◽  
Freeze Substitution ◽  
Critical Point Drying ◽  
Sem Study ◽  
Major Factors ◽  
Structural Preservation ◽  
Preparation Techniques

Three major factors must be concomitantly assessed in order to extract relevant structural information from the surface of biological material at high resolution (2-3nm).Procedures based on chemical fixation and dehydration in graded solvent series seem inappropriate when aiming for TEM-like resolution. Cells inevitably shrink up to 30-70% of their initial volume during gehydration; important surface components e.g. glycoproteins may be lost. These problems may be circumvented by preparation techniques based on cryofixation. Freezedrying and freeze-substitution followed by critical point drying yields improved structural preservation in TEM. An appropriate preservation of dimensional integrity may be achieved by freeze-drying at - 85° C. The sample shrinks and may partially collapse as it is warmed to room temperature for subsequent SEM study. Observations at low temperatures are therefore a necessary prerequisite for high fidelity SEM. Compromises however have been unavoidable up until now. Aldehyde prefixation is frequently needed prior to freeze drying, rendering the sample resistant to treatment with distilled water.

Investigations on the Nature of Hemophilia A

1963 ◽  
Vol 09 (01) ◽  
pp. 030-052 ◽  
Author(s):  
Eberhard Mammen
Keyword(s):  
Factor Viii ◽  
Human Plasma ◽  
Barium Sulfate ◽  
Freeze Drying ◽  
Room Temperature ◽  
Hemophilia A ◽  
Normal Human Plasma ◽  
Normal Human ◽  
And Storage ◽  
Prothrombin Activation

SummaryIn this paper an inhibitor is described that is found in hemophilic plasma and serum different from any till now described inhibitor. The inhibitor only inhibits prothrombin activation in the “intrinsic clotting systems”. This inhibitor is probably not present in normal human plasma or serum. It is destroyed by ether and freeze drying, is labile to acid and storage at room temperature. It is stable upon dialysis and has not been adsorbed on barium sulfate, aluminum hydroxide or kaolin. It precipitates at 50% v/v saturation with alcohol. The nature of this inhibitor seems to be a protein or lipoprotein.Factor VIII was isolated from hemophilic plasma. The amount isolated was the same as from normal plasma and the activity properties were not different. Hemophiliacs have normal amounts of factor VIII.

scholarly journals Evaluation of Innovative Dried Purée from Jerusalem Artichoke—In Vitro Studies of Its Physicochemical and Health-Promoting Properties

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2644
Author(s):  
Jan Oszmiański ◽  
Sabina Lachowicz ◽  
Paulina Nowicka ◽  
Paweł Rubiński ◽  
Tomasz Cebulak
Keyword(s):  
Freeze Drying ◽  
Jerusalem Artichoke ◽  
Polyphenolic Compounds ◽  
Raw Material ◽  
Vacuum Drying ◽  
Drying Methods ◽  
Drying Method ◽  
Activity Inhibition ◽  
Health Promoting

The present study aimed to evaluate the effect of Jerusalem artichoke processing methods and drying methods (freeze drying, sublimation drying, vacuum drying) on the basic physicochemical parameters, profiles and contents of sugars and polyphenolic compounds, and health-promoting properties (antioxidant activity, inhibition of the activities of α-amylase, α-glucosidase, and pancreatic lipase) of the produced purée. A total of 25 polyphenolic compounds belonging to hydroxycinnamic phenolic acids (LC-PDA-MS-QTof) were detected in Jerusalem artichoke purée. Their average content in the raw material was at 820 mg/100 g dm (UPLC-PDA-FL) and was 2.7 times higher than in the cooked material. The chemical composition and the health-promoting value of the purées were affected by the drying method, with the most beneficial values of the evaluated parameters obtained upon freeze drying. Vacuum drying could offer an alternative to freeze drying, as both methods ensured relatively comparable values of the assessed parameters.

scholarly journals Environmentally Friendly and Multifunctional Shaddock Peel-Based Carbon Aerogel for Thermal-Insulation and Microwave Absorption

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Weihua Gu ◽  
Jiaqi Sheng ◽  
Qianqian Huang ◽  
Gehuan Wang ◽  
Jiabin Chen ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Thermal Insulation ◽  
Freeze Drying ◽  
Thermal Infrared ◽  
Carbon Aerogel ◽  
Carbon Aerogels ◽  
List Type ◽  
Drying Method ◽  
Cross Sectional ◽  
Compression Resistance

Highlights The eco-friendly shaddock peel-derived carbon aerogels were prepared by a freeze-drying method. Multiple functions such as thermal insulation, compression resistance and microwave absorption can be integrated into one material-carbon aerogel. Novel computer simulation technology strategy was selected to simulate significant radar cross-sectional reduction values under real far field condition. . Abstract Eco-friendly electromagnetic wave absorbing materials with excellent thermal infrared stealth property, heat-insulating ability and compression resistance are highly attractive in practical applications. Meeting the aforesaid requirements simultaneously is a formidable challenge. Herein, ultra-light carbon aerogels were fabricated via fresh shaddock peel by facile freeze-drying method and calcination process, forming porous network architecture. With the heating platform temperature of 70 °C, the upper surface temperatures of the as-prepared carbon aerogel present a slow upward trend. The color of the sample surface in thermal infrared images is similar to that of the surroundings. With the maximum compressive stress of 2.435 kPa, the carbon aerogels can provide favorable endurance. The shaddock peel-based carbon aerogels possess the minimum reflection loss value (RLmin) of − 29.50 dB in X band. Meanwhile, the effective absorption bandwidth covers 5.80 GHz at a relatively thin thickness of only 1.7 mm. With the detection theta of 0°, the maximum radar cross-sectional (RCS) reduction values of 16.28 dB m2 can be achieved. Theoretical simulations of RCS have aroused extensive interest owing to their ingenious design and time-saving feature. This work paves the way for preparing multi-functional microwave absorbers derived from biomass raw materials under the guidance of RCS simulations.

scholarly journals Biocompatibility and osteoconductivity of scaffold porous composite collagen–hydroxyapatite based coral for bone regeneration

2020 ◽  
Vol 18 (1) ◽  
pp. 584-590 ◽  
Author(s):  
◽  
Dyah Hikmawati ◽  
Umi Kulsum ◽  
Djony Izak Rudyardjo ◽  
Retna Apsari ◽  
...  
Keyword(s):  
Bone Regeneration ◽  
Freeze Drying ◽  
Bone Growth ◽  
Viable Cell ◽  
Drying Method ◽  
Porous Composite ◽  
Viable Cells

AbstractThe synthesis of collagen–hydroxyapatite composites has been carried out, and the biocompatibility and osteoconductivity properties have been tested. This research was conducted to determine the ability of hydroxyapatite–collagen composites to support the bone growth through the graft surface. Hydroxyapatite used in this study was synthesized from coral with a purity of 96.6%, while collagen was extracted from the chicken claw. The process of forming a scaffold of collagen–hydroxyapatite composites was carried out using the freeze-drying method at −80°C for 4 h. The biocompatibility characteristics of the sample through the cytotoxicity tests showed that the percentage of viable cells in collagen–hydroxyapatite biocomposite was 108.2%, which is higher than the percentage of viable cells of hydroxyapatite or collagen material. When the viable cell is above 100%, collagen–hydroxyapatite composites have excellent osteoconductivity as a material for bone regeneration.

Construction of a CsPbBr3 modified porous g-C3N4 photocatalyst for effective reduction of CO2 and mechanism exploration

2021 ◽  
Author(s):  
Yunqi Wang ◽  
Zhixiang Liu ◽  
Xu Tang ◽  
Pengwei Huo ◽  
Zhi Zhu ◽  
...  
Keyword(s):  
High Temperature ◽  
Porous Structure ◽  
Freeze Drying ◽  
Drying Method ◽  
Full Spectrum ◽  
Effective Reduction ◽  
Reduction Of Co2 ◽  
High Temperature Calcination

A P-CN/CsPbBr3 photocatalyst with a lamellar porous structure was prepared by a high temperature calcination and freeze drying method, and it exhibited superior CO2 reduction performance under the conditions of full spectrum irradiation.

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