Oven Treatment Research Articles

Surface chemical analysis of photocatalytic wettability conversion of TiO2 nanoparticle coating

Surface chemical analysis of photocatalytic wettability conversion of the TiO2 nanoparticle coating is performed by the water contact angle measurement and X-ray photoelectron spectroscopy (XPS). It is observed that the UVA irradiation and heat treatment strongly affect on the water contact angle. Initially superhydrophobic TiO2 nanoparticle coated paperboard surfaces can undergo several transition loops between hydrophobic and hydrophilic states: the surface hydrophilicity can be induced by ultraviolet A (UVA) radiation whereas high temperature oven treatment results in superhydrophobic surface. The XPS spectra shows that UVA irradiation induces photocatalytic oxidation of the TiO2 nanocoated surface whereas the oven treatment decreases the amount of oxygen related to the hydroxyl groups. The wettability changes are related to the degree of hydroxyl groups or aliphatic chains present on the TiO2 surface.

边角Zara Domain及其改善研究

The dependence of Zara domain(corner) on LC pattern has been studied.The experimental results show that,when no LC drop in the corner of LC pattern,Zara domain(corner) easily occurs.By adding LC drop in the corner of LC pattern,the incidence of Zara domain(corner)can be reduced.By adjusting the distance to Active Area,the incidence of Zara domain(corner) is the lowest.On the conditions for LC Pattern 5,Zara domain(corner) is 2.5%,and then disappears after oven treatment.

황벽 추출염료와 염직물의 열적 퇴화 거동 연구

This research compares the change in berberine content in liquid dye and the color and dye uptake of amur cork tree dyed silk upon thermal degradation treatment. Thermal degradation of amur cork tree extract and liquid dye of standard berberine was carried out at room temperature, <TEX>$4^{\circ}C$</TEX> refrigeration, and <TEX>$100^{\circ}C$</TEX> oven conditions for 0-192 hours. Amur cork tree dyed silk was treated in a <TEX>$100^{\circ}C$</TEX> oven for 0-240 hours. The berberine content in liquid dye was measured by the relative abundance of the berberine peak in the HPLC-MS chromatograms. The color and dye uptake of dyed silk was measured using K/S value and colorimetric data. The berberine content in standard berberine dye was 2.4 times that of the amur cork tree extract. A similar result was observed between the K/S value of standard berberine dyed silk and that of amur cork tree dyed silk. The berberine dyed silk showed the highest dye uptake after 120 hours in a <TEX>$100^{\circ}C$</TEX> oven. This result was similar to the change in a berberine content in liquid dye in a <TEX>$100^{\circ}C$</TEX> oven treatment. The change of the K/S value of amur cork tree dyed silk and berberine content of amur cork tree extract was similar up to 24 hours. The result suggests that there is a direct relationship between the color change of amur cork tree dyed silk and the berberine content in amur cork tree dye.

Evaluation of Strength Properties of Polypropylene-Based Polymers in Simulated Landfill and Oven Conditions

Polymeric films and fibers are used extensively in industrial and personal products. Many of these products are intended to be disposable and, after initial use, are disposed in landfills that are increasingly expensive and limited. Proprietary additives are being promoted to enhance the biodegradation of polypropylene (PP) and related materials. A test was run on samples of diapers containing PP in simulated landfills and in convection ovens over a period of 52 weeks. Samples in the oven treatment lost all strength properties in less than 27 weeks. Back sheet and cuff samples in the landfill lost insignificant (P<0.05) strength under landfill conditions over 52 weeks. Statistics show significant differences (P<0.05) in strength and sample percent elongation during testing for time, temperature, and time-temperature interactions for both the oven and landfill tests. The study led to the conclusion that the polypropylene additive was efficacious for programmable destruction in an oxidative environment but ...

Comparative Study of Different Techniques for the Sterilization of Poly-L-lactide Electrospun Microfibers: Effectiveness vs. Material Degradation

Electrospinning of biopolymeric scaffolds is a new and effective approach for creating replacement tissues to repair defects and/or damaged tissues with direct clinical application. However, many hurdles and technical concerns regarding biological issues, such as cell retention and the ability to grow, still need to be overcome to gain full access to the clinical arena. Interaction with the host human tissues, immunogenicity, pathogen transmission as well as production costs, technical expertise, and good manufacturing and laboratory practice requirements call for careful consideration when aiming at the production of a material that is available off-the-shelf, to be used immediately in operative settings. The issue of sterilization is one of the most important steps for the clinical application of these scaffolds. Nevertheless, relatively few studies have been performed to systematically investigate how sterilization treatments may affect the properties of electrospun polymers for tissue engineering. This paper presents the results of a comparative study of different sterilization techniques applied to an electrospun poly-L-lactide scaffold: soaking in absolute ethanol, dry oven and autoclave treatments, UV irradiation, and hydrogen peroxide gas plasma treatment. Morphological and chemical characterization was coupled with microbiological sterility assay to validate the examined sterilization techniques in terms of effectiveness and modifications to the scaffold. The results of this study reveal that UV irradiation and hydrogen peroxide gas plasma are the most effective sterilization techniques, as they ensure sterility of the electrospun scaffolds without affecting their chemical and morphological features.

Development of large area photovoltaic dye cells at 3GSolar

Dye solar cells (DSCs) are a low-cost alternative to photovoltaic silicon and thin film cells on the basis of materials (bulk titania powder in place of high purity semiconductors such as silicon) and process costs (simple screen printing and oven treatment in air in place of vacuum deposition). 3GSolar Ltd., with a novel DSC design based on a robust silver-free current collecting grid, have developed commercial size, sealed prototype glass-based cells of area 225 sq cm and assembled them into multicell prototype PV modules. Performance data are presented for these prototypes, which are on schedule towards pilot production (2010) and industrial production (2011) of cells and modules.

A Study of the Mechanical Properties and Recrystallization of Two Types of Foil of Aluminium 1050 A

An experimental study of the variation of the mechanical properties of sheets of aluminium alloy 1050A due to heat treatment has been carried out. For this purpose, sheets and foils rolled from continuous casting strip (CCS) and from hot rolling strip (HRS) have been prepared in the laboratory. Initially, CCS and HRS had a thickness of 7,5 mm and 3,0 mm respectively. The final thickness achieved in both cases was 0,20 mm. In order to obtain hardening curves for CCS and HRS sheets and foils, specimens of different thickness were taken during the rolling process. Oven treatments were carried out for drawing softening curves of foils. Foil proceeding from CCS presents hardening due to the precipitation of Al3Fe particles at a temperature range of 160°C to 220 °C. HRS foil has a lower hardening in the same range of temperatures owing to its low supersaturation of Fe. Correlation between ultimate tensile strength Rm and Vickers hardness is studied. Micrographies of optical microscopy are offered at hard and recrystallized conditions.

Processing of Bi 1.5ZnNb 1.5O 7 ceramics for LTCC applications: Comparison of synthesis and sintering methods

Bismuth zinc niobate posses a cubic pyrochlore structure and normally is obtained by the conventional solid-state reaction. The great disadvantage of this method is the lack of chemical homogeneity, requiring high synthesis and sintering temperatures (higher than 1000 °C), which is an impeditive for BZN application in LTCC with silver as the internal electrode. The aim of this paper is to compare, from synthesis to sintering, BZN ceramics, derived either from chemically or conventionally synthesized powders, sintered either in both conventional oven for 2 h or microwave oven for 15 min. The results showed that chemically synthesized BZN ceramics sintered in microwave oven at 900 °C for 15 min presented a relative density of 97%, while those obtained by conventional method required 1000 °C to reach the same density. Despite the short period for thermal treatment in microwave oven, the electrical properties of BZN ceramics are compatible with those sintered in conventional oven for 2 h.

Extractive composition and summative chemical analysis of thermally treated eucalypt wood

Abstract Eucalypt wood (Eucalyptus globulus) was heated in an oven for 2–24 h at 170–200°C and in an autoclave with superheated and saturated steam for 2–12 h at 190–210°C. The chemical composition of untreated wood and thermally treated wood with different mass losses in the range of 1.1–11.9% was studied by summative analysis, and the composition of dichloromethane, ethanol and water extracts was determined by gas chromatography mass spectometry (GC-MS). The hemicelluloses degraded first, mainly regarding the arabinose and xylose moieties. Lignin degraded at a slower rate and cellulose was only slightly affected under severe treatment conditions. The extractive content increased first with heat treatment and decreased later on. Almost all of the original extractives disappeared and new compounds were formed, such as anhydrosugars, mannosan, galactosan, levoglucosan and two C5 anhydrosugars. The most prominent lignin derived compounds were syringaldehyde, syringic acid and sinapaldehyde. The main difference between autoclave and oven treated samples was the appearance of more oxidized extractives for the oven treatment.

An Investigation on the Germination of Seeds of Kwao Kreu Kao (Pueraria candollei Grah. Ex Benth) as Affected by Both Water Soakings and Hot Air Oven Treatments

This experiment was carried out at the Faculty of Technology, Mahasarakham University, Mahasarakham 4400, Thailand to investigate effects of different water-soaking durations and hot air oven treatments on the germination of seeds of Kwao Kreu Kao (Pueraria candollei Grah. ex Benth) plants. The experiment was laid in a Randomised Complete Block Design with four replications. The results showed that after tested for Electrical Conductivity (EC) values for cracking of seeds, all seeds being used were at a normal condition (with an average EC value of 28.56 microS cm(-1) g(-1)) and all seeds were ready for germination. Strength on impermeability of seeds declined after soaking in water for 10 h and onwards then the treated seeds had increased in weights. However, after treated under hot air oven, dry weights of all seeds became similar. Germination percentage of all treatments was most rapid during the first three weeks of germination period and later slowly increased with time. At day 91 after sowing, T2 gave the highest percentage of germination (52%) and the lowest was found with T1 (control) with 31.25%. Again at day 91 after sowing, T2 gave the highest mean value of plant numbers (16.38) and the lowest was found with T1 (7.28). Numbers of abnormal seedlings determined at day 63 after sowing were lowest with T2 (6.25%) and worst with T4 (20.14%). Again at day 63 after sowing, plant height was significantly tallest with T2 (3.88 cm) and the lowest was found with T4 (2.71 cm). Numbers of leaves were not significantly different among the treated plants reaching a highest value of 11.25 leaves plant(-1) for T3. It may be concluded that T2 was the best treatment for use in germinating seeds of Pueraria candollei Grah. ex Benth plants. Further improvements on longevity and high percentage of germination of seeds were discussed and suggested.

Effect of Moisture Absorption on the Tensile Properties of Steam-exploded Acacia mangium Fiber–Polypropylene osites

Polypropylene-filled alkali-extracted steam-exploded Acacia mangium fiber (AEF–PP) composites are immersed in water at room temperature for three months. All composites, including those with maleated polypropylene (MAPP) are found to absorb water considerably. The results of tensile properties indicate that the properties deteriorate following water absorption. The addition of MAPP to the composite systems (AEF–PP–MAPP) does not help in retaining the tensile properties. Scanning electron microscopy (SEM) examinations of the fracture surfaces of AEF–PP–MAPP composites reveal degradation of interfacial interaction. The composites, however, recover more than 90% of the tensile properties after oven treatment probably due to recovery of interfacial interaction as evident in scanning electron micrographs. The tensile properties recoveries for AEF–PP composites are fewer than for those with MAPP. Permanent damages in composite structures due to water absorption might account for this result.

A new analytical approach for humin determination in sediments and soils

In this work a new analytical approach is proposed for the recovery of humin present in soil and sediments. The procedure is based on microwave oven treatment for humin deashing. In this way both the treatment time and the concentration of the HCl/HF mixture are significantly reduced (minutes rather than hours, 10% rather than concentrated). By means of the proposed scheme organic matter present in sediment and soil samples can be subdivided into the different fractions (hydrophobic and hydrophilic compounds, fulvic and humic acids, humin) making up the balance of organic carbon. Results obtained for samples characterised by different organic carbon content showed a loss of carbon ranging between 20% and 30%, consistent with previous reports about humin deashing.

Survivability of Salmonella cells in popcorn after microwave oven and conventional cooking

The survivability of Salmonella cells in popcorn preparation was determined for two distinct cooking methods. The first method used a standard microwave oven. The second method used conventional cooking in a pan. Prior to thermal processing in independent experiments, 12 suspensions in a range between 1x10(3) and 8x10(6) colony-forming units (CFU) per gram of Salmonella cells were inoculated in both raw microwave popcorn and conventional corn kernels. The influence of the initial concentration of Salmonella cells in the raw products and the lethal effects on Salmonella by thermal treatments for cooking were studied. Survival of Salmonella cells was determined in the thermally processed material by pre-enrichment and enrichment in selective medium, in accordance with the legislation for expanded cereals and cereals in flakes. Viable experimental contaminants were recovered from the conventionally cooked popcorn with initial inoculation concentrations of 9x10(4)cells/g or greater. Salmonella cell viability was significantly reduced after microwave oven treatment, with recoveries only from initial concentrations of 2x10(6)cells/g or superior.

Prostaglandin E2 Regulates the Nuclear Receptor NR4A2 in Colorectal Cancer

Many lines of research implicate cyclooxygenase 2-derived prostaglandins in tumor growth and metastasis. More specifically, we have shown that prostaglandin E2 (PGE2) promotes cell proliferation and invasion through transactivation of the epidermal growth factor receptor, initiates immune evasion through induction of decay accelerating factor, and transactivates peroxisome proliferator-activated receptor delta, leading to increased polyp size and multiplicity. We continue to identify novel PGE2 target genes in colorectal carcinoma cells and report here that an immediate early gene, nuclear factor NR4A2 (Nurr1), is induced by PGE2 that in turn regulates cell death. Originally described as a critical dopaminergic neuron growth factor receptor, NR4A2 expression is rapidly but transiently induced by PGE2 in a cAMP/protein kinase A-dependent manner. NR4A2 binds to the cognate NBRE response element and enhances transcription of a reporter construct in colorectal carcinoma cells. Furthermore, NR4A2 expression is elevated in Apc-/+ mouse adenomas and its levels were further increased following PGE2 treatment. Human colorectal cancers relative to matched normal mucosa showed increased NR4A2 expression. Although not previously described in epithelial tissues, NR4A2 protein localizes to proliferating crypts of Apc-/+ mouse intestine. Finally, functional studies reveal that PGE2-mediated protection from apoptosis is completely inhibited by a dominant-negative NR4A2 construct. Building on previous reports from our group on the peroxisome proliferator-activated receptor family of nuclear receptors, these most recent data suggest that NR4A2, a member of another family of nuclear receptors can stimulate progression of colorectal cancer downstream from cyclooxygenase 2-derived PGE2.

Novel Heparan Sulfate Structures Revealed by Monoclonal Antibodies

The sulfated glycosaminoglycan heparan sulfate (HS) is found ubiquitously on cell surfaces, in the extracellular matrix, and intracellularly as HS proteoglycans. Because of the structural heterogeneity of HS, tissue-derived HS preparations represent a mixture of HS chains originating from different cell types and tissue loci. Monoclonal anti-HS antibodies have been employed to detect the localization of specific HS epitopes in tissues, but limited information has been available on the saccharide structures recognized by the antibodies. We have studied the saccharide epitope structures of four anti-HS antibodies, HepSS1, JM13, JM403, and 10E4, which all recognize distinct HS species as demonstrated by different patterns of immunoreactivity upon staining of embryonic rat and adult human tissues. The epitopes recognized by JM13 and HepSS1 were found almost exclusively in basement membrane HS, whereas JM403 and 10E4 reacted also with cell-associated HS species. The binding of HepSS1, JM403, and 10E4 to HS was dependent on the GlcN N-substitution of the polysaccharide rather than O-sulfation. HepSS1 thus interacted with N-sulfated HS domains, JM403 binding was critically dependent on N-unsubstituted GlcN residues, and 10E4 bound to "mixed" HS domains containing both N-acetylated and N-sulfated disaccharide units. By contrast, JM13 binding seemed to require the presence of 2-O-sulfated glucuronic acid residues.

Modification of Gelatinization Properties of Rice Flour by Heat-Treatment

The effects of autoclave and oven treatments on gelatinization properties of rice flour and on crystallite structures of rice starch in rice flour were studied using dynamic oscillatory measurement, differential scanning calorimetry (DSC), X-ray diffractometry, and scanning electron microscopy (SEM). Autoclave-treated rice flour (ATR) and oven-treated rice flour (OTR) were prepared using an autoclave at 120 °C for 60 min and oven at 160 °C for 60 min. Dynamic oscillatory and DSC measurements demonstrated that autoclave treatment modified the gelatinization properties that delayed gelatinization temperature (TG' and To) and decreased in peak storage modulus (G'p). Autoclave treatment caused formation of amylose-lipid complexes and partial gelatinization of starch granules in ATR studied by DSC and X-ray diffractometry. Autoclave-treatment engendered formation of amylose-lipid complexes and partial gelatinization of starch granules in ATR studied by DSC and X-ray diffractometry. Alteration of gelatinization properties of ATR flour is attributed to changes in rigidity of starch granules during treatment. Similarly to ATR, oven treatment was effective for gelatinization properties. Nevertheless, it was insufficient for rearrangement of starch chains in OTR flour.

Plasma methionine and lysine concentrations of early lactating Holstein cows fed diet containing raw or roasted Iranian soybean variety

Whole soybean has 19 percent ether extract and 42 percent CP and is used as a high energy-protein supplement for early lactation dairy cows, but the protein is highly degradable, so small amounts of amino acids can reach the small intestine to meet high amino acid requirements in early lactation. Therefore, various chemical and physical treatments have been suggested to decrease ruminal protein degradability. The practical use and application of any one method to lower ruminal feed degradability is dependent not only on its efficacy but also on its cost effectiveness, safety and ease of application. For these reasons, heat treatment is the most commonly used physical method. Energy expenditure and fixed costs are lower for roasting than for oven treatment, thereby warranting further research on this type of heat treatment (Plegge et al., 1985). The purpose of this study was to determine how roasting of soybeans affect Met and Lys plasma levels (as the first limiting amino acids in milk yield) in early lactation cows.

Microstructural study of frozen batter-coated squid rings prepared by an innovative process without a pre-frying step

Cryo-Scanning Electron Microscopy was used to study the microstructure of frozen batter-coated products prepared by an innovative process. This recently patented process makes possible to eliminate the industrial pre-frying stage that coagulates the batter layer and replace it by coagulation in a hot water bath at 70 °C followed by a short thermal treatment in a microwave oven. The innovative process is made possible by adding methylcellulose to the batter formula. The microscopic observations show that adding this cellulose derivative to the batter formula produces a microstructural matrix that favors the coating–food interaction. After immersing the batter-coated product in hot water, the coating was found to have developed a consolidated structure. This was further reinforced by the microwave oven step, allowing the product to be handled without deteriorating. Maintenance of good adhesion between the coating and the food (squid) surface was observed in the final fried product as well.

Surfactants treatment of crude oil contaminated soils.

This study reports experimental measurements investigating the ability of a biological (rhamnolipid) and a synthetic (sodium dodecyl sulfate, SDS) surfactant to remove the North Sea Ekofisk crude oil from various soils with different particle size fractions under varying washing conditions. The washing parameters and ranges tested were as follows: temperature (5 to 50 degrees C), time (5 to 20 min), shaking speed (80 to 200 strokes/min), volume (5 to 20 cm3), and surfactant concentration (0.004 to 5 mass%). The contaminated soils were prepared in the laboratory by mixing crude oil and soils using a rotating cylindrical mixer. Two contamination cases were considered: (1) weathered contamination was simulated by keeping freshly contaminated soils in a fan assisted oven at 50 degrees C for 14 days, mimicking the weathering effect in a natural hot environment, and (2) nonweathered contamination which was not subjected to the oven treatment. The surfactants were found to have considerable potential in removing crude oil from different contaminated soils and the results were comparable with those reported in literature for petroleum hydrocarbons. The removal of crude oil with either rhamnolipid or SDS was within the repeatability range of +/-6%. The most influential parameters on oil removal were surfactant concentration and washing temperature. The soil cation exchange capacity and pH also influenced the removal of crude oil from the individual soils. However, due to the binding of crude oil to soil during weathering, low crude oil removal was achieved with the weathered contaminated soil samples.

Do Natural Silks Make Good Engineering Materials?

AbstractFast relaxation of stresses lower than the yield stress is demonstrated in Bombyx mori(silkworm) cocoon silk and Nephila clavipes (spider) major ampullate silk (MAS; dragline). Stress relaxation and creep make natural silk unsuitable as a long-term load-bearing material. Instead, silk-like materials are better suited to applications in which energy dissipation is important, and in which high loads need to be withstood on a once-off basis for only very short periods of time. Examples might include use as a ballistic material that arrests the penetration of fragments from the explosion of a pressure vessel, an aircraft luggage container, or a tyre. Treatment in a domestic microwave oven is shown to significantly reduce the rate of stress relaxation in both silkworm cocoon and spider MAS. Except for ductility, the tensile properties of cocoon silk measured in constant strain rate experiments are enhanced by this treatment. Initial experiments on MAS suggest that the tensile properties of this material also are enhanced by exposure to microwaves, in this case with the exception of initial modulus.