Vapor Heat Treatment Research Articles

Perlakuan Uap Panas (Vapor Heat Treatmant) untuk Disinfestasi Lalat Buah dan Memperthankan Mutu Buah Belimbing (Averrhoa Carambola L.)

The objectives of this research were to study mortality of carambola fruit fly (B. carambolae D & H) and to study responses of VHT on quality of carambola (A. carambola L). Fruit fly mortality due to heat has been investigated by immersing fruit fly eggs into hot water at temperatures of 40, 43, 46 dan 49oC for 30 minutes and then at temperature of 46.5oC for 0, 5, 10, 15, 20, 25, 30 minutes. Star fruit were treated at temperature of 46.5oC for 5, 15, 30 minutes and then stored in temperatures of 5, 15oC and room temperature (28-30 oC). The result show that mortality has been achieved 100% at temperature more than 43.0oC for 30 minutes and at temperature 46.0oC for more than 15 minutes. VHT had significant influences to decrease the fruit respiration rates, chilling injury, antraknose, to increase the weight loss, color, and soluble solid content. However, there were no significant change in the hardness, water content, vitamin C and organoleptic test. VHT at temperature 46.5oC for 20 up to 30 minutes were effective to kill fruit flies inside carambola and VHT combined by storing in temperature of 15oC were able to maintain carambola quality during storage.Keywords: vapor heat treatment, fruit fly, B. carambolae, carambola, disinfestationDiterima: 1 Februari 2010; Disetujui: 19 April 2010

Effect of Hot-water and Vapor-heat Treatments on the Control of Stem-end Rot of Papaya

Effect of Hot-water and Vapor-heat Treatments on the Control of Stem-end Rot of Papaya

Defect Reduction in Polycrystalline Silicon Thin Films at 150 °C

We report defect reduction in 50-nm-thick laser-crystallized polycrystalline silicon (poly-Si) films by a combination of hydrogen plasma at 100 W for 5 s at room temperature with 4.7×105 Pa H2O vapor heat treatment at 150 °C for 6 h. The present treatment increased the photoconductivity to 1×10-3 S/cm for undoped poly-Si films under the illumination of 532 nm light at 100 mW/cm2. It also increased the electrical conductivity to 30 S/cm for 2×1019 cm-3 phosphorus-doped poly-Si films. Those values were comparable to those for samples treated with 1.3×106 Pa H2O vapor heat treatment for 3 h at 260 °C. Hydrogen concentration increased from 1.6 to 5.4 at. % as hydrogen plasma duration increased from 5 to 120 s. It was decreased by subsequent H2O vapor heat treatment at 150 °C, and ultimately ranged from 1.1 to 4.5 at. %. Hydrogen atoms play a catalytic role in the dissociation of H2O molecules at 150 °C.

A Study on the Properties of MgF2Antireflection Film for Solar Cells

<TEX>$MgF_2$</TEX> is a current material used for optical applications in the ultraviolet and deep ultraviolet range. Process variables for manufacturing <TEX>$MgF_2$</TEX> thin film were established in order to clarify the optimum conditions for the growth of the thin film, dependant upon the process conditions, and then by changing a number of the vapor deposition conditions, substrate temperatures, and heat treatment conditions, the structural and optical characteristics were measured. Then, optimum process variables were thus derived. Nevertheless, modern applications still require improvement in the optical and structural quality of the deposited layers. In the present work, in order to understand the composition and microstructure of <TEX>$MgF_2$</TEX>, single layers grown on a slide glass substrate using an Electron beam Evaporator (KV-660), were analyzed and compared. The surface substrate temperature, having an effect on the quality of the thin film, was changed from <TEX>$200^{\circ}C$</TEX> to <TEX>$350^{\circ}C$</TEX> at intervals of <TEX>$50^{\circ}C$</TEX>. The heat treatment temperature, which also has an effect on the thin film, was changed from <TEX>$200^{\circ}C$</TEX> to <TEX>$400^{\circ}C$</TEX> at intervals of <TEX>$50^{\circ}C$</TEX>. The physical properties of the thin film were investigated at various fabrication conditions, such as the substrate temperature, the heat treatment temperature, and the heat treatment time, by X-ray diffraction, and field emission-scanning electron microscopy.

High-Pressure Water Vapor Heat Treatment for Enhancement of SiOx or SiNx Passivation Layers of Silicon Solar Cells

For the production of low-cost and high-efficiency silicon solar cells, it is necessary to develop high-quality passivation techniques at low temperatures. In this study, we propose high-pressure water vapor heat treatment (HWT) as a technique for modifying the passivation layers of silicon solar cells at low temperatures. HWT at approximately 300 °C was performed on mono- and multicrystalline silicon solar cells with SiOx or SiNx passivation layers formed by plasma-enhanced chemical vapor deposition at 300 °C. After the treatment, the improvement of passivation effect was confirmed by better photovoltaic performance, electroluminescence emission intensity, and effective minority carrier lifetime. Fourier transform infrared spectrometry proved that HWT caused the formation of a Si–O–Si bonding network that terminates the silicon dangling bonds at the surface or at defects, resulting in reduced recombination.

Desain dan Kinerja Unit Perlakuan Uap Panas (VHT) untuk Disinfestai Lalat Buah pada Penanganan Pascapanen Mangga

Formerly, chemical fumigation was used for disinfestation treatment, but now had been replaced bychemical-free disinfestations treatment such as vapor heat treatment (VHT). The objectives of this researchwere (1) to design the VHT Unit and testing its performances, and (2) to study the effect of the VHT methodand waxing on the fruit quality during storage of mango. The designs of VHT unit consist of water tank, filter,heater, water pump, differential pressure fan, atomizer, control panel and treatment chamber. Performanceof the unit showed that the temperature of the VHT chamber increased from ambient temperature of 30OCto setting point of 47OC in 70 minutes. Relative humidity of the VHT chamber was very high (more than90%) indicating the VHT unit was successful in being used for fruitfly disinfestations of fruit product. Usingsetting point of 46.5OC, the mango fruit core temperature reached temperature of 45.5-46.3OC in 130minutes. Mango ‘Gedong gincu’ were treated at 46.5OC for 10, 20, 30 minutes and control and then followedby waxing. The results showed that VHT of 10-30 minutes were not significantly affect the fruit quality.There were no significant changes in the fruit weight losses, hardness, color, soluble solid content, watercontent and vitamin C. VHT at 46.5OC for 20-30 minutes was effective to kill the fruitfly infested inside themangos and VHT followed by waxing was able to maintain mango quality during storage.Keywords : mango, fruit fly, heat quarantine treatment, vapor heat treatment (VHT)Diterima: 15 Januari 2008; Disetujui: 27 Agustus 2008

Kajian Disinfestasi Lalat Buah (Bactrocera dorsalis) dengan Perlakuan Uap Panas (Vapor Heat Treatment) pada Mangga Gedong Gincu

Since the prohibition of chemical method for insect disinfestations processes such as ethylene dibromide in 1984, heat treatment method was developed as quarantine technology. One of the heat treatment methods is vapor heat treatment (VHT). The objectives of this research were to study mortality of fruit fly (Bactrocera dorsalis) and to study the responses of VHT on quality of gedong gincu mango. Fruit fly mortality due to heat has been investigated by immersing fruit fly eggs into heated water at temperatures of 40, 43, 46 and 49OC for 30 minutes immersed, also at temperature of 46OC for 5, 10, 15, 20, 25 and 30 minutes. Gedong gincu mangoes were treated at temperature 46.5OC for 0, 10, 20, and 30 minutes. The results showed that mortality has been achieved 100% at temperature more than and equal to 43OC for 30 minutes and attemperature 46OC for more than and equal to 10 minutes. The VHT has significantly and fungi population although without adversely affecting to the fruit quality and there were no significant change in the fruit weight loss, hardness, color, soluble solid content, water content, vitamin C and organoleptic test. VHT at temperature 46.5OC for 20 up to 30 minutes were effective to kill fruit flies inside mangoes and were able tomaintaining mango quality during storage.Keywords : mango, fruit fly, disinfestations, vapor heat treatmentDiterima: 24 Maret 2008; Disetujui: 22 Oktober 2008

CONTROL OF Anastrepha serpentina (Wiedemann) AND QUALITY OF ZAPOTE MAMEY Pouteria sapota (Jacq) Moore &amp; Stearn FRUITS TREATED WITH VAPOR HEAT

The objectives of this study were to evaluate thermal treatments of vapor heat in the control of Anastrepha serpentina on zapote and to determine tolerance of zapote mamey fruits to the treatments. The fruits not were damaged internally by the heat treatment when exposed to 43 °C·120 min -1 . The fruits reached eating ripeness in 8 days at 25 °C, with rapid changes in the pulp color and weight loss. In contrast, at 10 °C they maintained greater firmness and prolonged shelf life, but exhibited greater damage in the vascular bundles. Mortality of the fruit fly eggs and larvae was 100 % with controlled atmosphere vapor heat treatment at 43 °C·120 min -1 . Fruits not

EFFECT OF VAPOR HEAT ON THE EXPORT QUALITY OF FRESH TOMATO (SOLANUM LYCOPERSICUM L.)

Postharvest heat treatments have been used for fruit disinfestation of insects, disease control, and modification of reactions of the fruits to physiological stress produced by postharvest treatments with low temperatures. The present study evaluated the effect of the application of vapor heat at 46°C on the quality of the 'Long Life' variety tomato at two maturity stages and two fruit sizes; fruit sizes chosen were: a) between 280-450 g, and b) between 200 and 279.9 g; the evaluated maturity grades were breaker stage and green stage. The measured parameters were the quantitative: weight loss, firmness, soluble solids, pH, and citric acid and qualitative ones: external appearance, internal appearance, and flavor. The treatment with vapor heat did not produce satisfactory results in respect to the quality of the tomato fruits. Some of the quantitative parameters revealed statistical differences when comparing the treated fruits with the control, but not all of these fruits were rejected in the sensory evaluation. The main parameters of rejection were the qualitative variables and the external appearance was the major factor of non-acceptance. The results presented in this investigation showed that the 'Long Life' variety of tomato grown in Colombia did not tolerate the vapor heat treatment applied.

Analysis of Microwave Absorption Caused by Free Carriers in Silicon

Microwave absorption caused by free carriers was investigated. A 9.35 GHz microwave interferometer was constructed. The transmissivity of 525-µm-thick silicon substrates decreased from 60.4 to 3.8% as the resistivity decreased from 1000 to 4 Ω cm. This characteristic was explained well by a numerical analysis using the free carriers absorption theory. Microwave free carrier photo absorption caused by light-induced carriers was also investigated for p-type silicon samples coated with 100 nm thermally grown SiO2 layers as well as SiOx layers deposited by the vacuum evaporation method. The effective minority carrier lifetime and recombination velocity were analyzed in the case of the photo induced carrier generation with 532 nm light illumination. The effective minority carrier lifetime was increased from 360 to 540 µs and the recombination velocity was decreased from 78 to 30 cm/s by 1.3 ×106 Pa H2O vapor heat treatment at 260 °C for 3 h for light illumination at 0.315 mW/cm2 in the case of the thermally grown SiO2/Si because of the passivation of SiO2/Si interfaces. They were markedly increased from 30 to 380 µs and from 1300 to 60 cm/s, respectively, by the H2O vapor heat treatment in the case of the vacuum-evaporated SiOx/Si.

Improvement in SiO2 Film Properties Formed by Sputtering Method at 150 °C

The quantity of hysteresis phenomena in capacitance response for metal–oxide–semiconductor (MOS) capacitors with 100-nm-thick SiO2 films formed by the sputtering method was reduced by remote oxygen plasma treatment followed by high-pressure H2O vapor heat treatment at 150 °C. In order to determine the quantity of hysteresis phenomena in capacitance response, we defined hysteresis charge as the difference in fixed oxide charge density for round bias voltage application. As-fabricated MOS capacitor samples had a high density of hysteresis charges of 1.0×1012 cm-2. The density of hysteresis charge was not decreased by 4.7×105-Pa-H2O-vapor heat treatment at 150 °C for 3 h. On the other hand, it was markedly reduced to 1.0×1011 cm-2 by 13.56-MHz-radio frequency remote oxygen plasma treatment at 300 W and 150 °C followed by 4.7×105-Pa-H2O-vapor heat treatment at 150 °C for 3 h. Hysteresis phenomena are probably caused by a temporal electron charging up of SiO2 films.

Effect of heat treatment in sulfur and mercury vapors on the magnetic susceptibility of Hg1 − x Mn x Te1 − y S y crystals

We have studied the effect of heat treatment in mercury and sulfur vapors on the magnetic susceptibility of Hg1 − xMnxTe1 − ySy crystals. Measurements were performed by the Faraday method in the temperature range 77–300 K at H= 318 kA/m before and after heat treatments. The results demonstrate that the behavior of the magnetic susceptibility can be understood in terms of Mn-S-Mn-S, Mn-Te-Mn-Te, and (mixed) Mn-Te-Mn-S clusters of different sizes with indirect antiferromagnetic exchange interaction between the Mn atoms through the chalcogen atoms. Heat treatment in sulfur and mercury vapors leads to the formation of new clusters or changes (increases or decreases) the size of already existing clusters.

Inactivation of parvovirus B19 during STIM‐4 vapor heat treatment of three coagulation factor concentrates

To enhance the viral safety margins, nanofiltration has been widely integrated into the manufacturing process of plasma-derived medicinal products. Removal of smaller agents such as parvovirus B19 (B19V) by filtration, however, is typically less efficient. Because recent investigations have demonstrated that B19V may be more heat sensitive than animal parvoviruses, the potential B19V inactivation by a proprietary vapor heating procedure (STIM-4) as incorporated into the manufacturing processes of several nanofiltered coagulation factor concentrates was investigated. An infectivity assay based on quantitative reverse transcription-polymerase chain reaction (TaqMan, Applied Biosystems) detection of B19V mRNA after inoculation of a permissive cell line (UT7 Epo S1 cells) was used to investigate the virus inactivation capacity of the STIM-4 vapor heat treatment as used during the manufacture of nanofiltered second-generation Factor VIII inhibitor-bypassing activity (FEIBA), F IX complex, and FVII products. In contrast to animal parvoviruses, both B19V genotypes investigated, that is, 1 and 2, were shown to be surprisingly effectively inactivated by the STIM-4 vapor heat treatment process, with mean log reduction factors of 3.5 to 4.8, irrespective of the product intermediate tested. The newly demonstrated effective inactivation of B19V by vapor heating, in contrast to the earlier used animal parvoviruses, results in significant B19V safety margins for STIM-4-treated coagulation factor concentrates.

Lama Pemanasan Metode Vapor Heat Treatment (VHT) dan Pelilinan untuk Mempertahankan Mutu Pepaya Selama Penyimpanan

Horticulture products are host for Tephritidae fruitflies that are considered a quarantine risk by many importing countries. This research was conducted to find out the specific condition for the heat treatment using vapor heat treatment (VHT) method to control pest and diseases of papaya and the fruit quality during storage. Papayas were vapor heat treated at medium temperature of 46.5 0C for 0, 15, and 30 minutes. After the treatment, the fruits were waxed using beeswax of 6 % in concentration and then stored at temperature of 10 0C. The results show that the fruitfly of oriental fruitfly (Bactrocera dorsalis) was completely killed by treating in deep water testing at temperature of 46 0C for 10 minutes or at 43 0C for 30 minutes. The VHT of papaya at fruit core temperature of 45.5-46.0 0C for 15-30 minutes following waxing using beeswax of 6% in concentration was found to be effective to control pest and diseases until 21 days of storage without any visible signs of heat injury and without adversely affecting the quality of the fruit. Keywords: Papaya, vapor heat treatment, waxing, quarantine Diterima: 20 Agustus 2007; Disetujui: 24 Nopember 2007

Aluminum hydroxide transformations during thermal and vapor heat treatments

We have studied the mechanisms underlying the formation of corundum crystals from hydrargillite and boehmite during thermal and vapor heat treatments and have identified the major stages in the formation of corundum structure, thought of as the evolution of the system toward the most thermodynamically stable state. The results indicate that isothermal autoclaving at temperatures from 390 to 450°C gives rise to structural changes in alumina, which involve the following stages: the formation of microcrystalline boehmite from coarser hydrargillite crystals, accompanied by disintegration of agglomerates, boehmite flocculation and dehydration, conversion of the dehydrated boehmite to alpha-alumina within each floccule, and formation of corundum single crystals. Unflocculated boehmite crystals are absorbed by the growing crystal faces. If presynthesized boehmite is used as the precursor, the process also involves flocculation, dehydration, conversion to alpha-alumina, and formation of corundum single crystals. The structural changes induced in hydrargillite and boehmite crystals by annealing in air and vacuum at temperatures from 1400 to 1500°C have been analyzed. The formation of alpha-alumina from boehmite below <1200°C is accompanied by no changes in crystal habit, whereas annealing in the range 1400–1500°C gives rise to sintering of fine alumina crystals and changes in crystal habit. The degree of alignment of the crystals is shown to influence their structural transformations.

Polysilazane Precursor Used for Formation of Oxidized Insulator

ABSTRACTWe report on SiO2 film formation using Polysilazane precursor treated with remote oxygen plasma and high-pressure H2O vapor heating. Polysilazane precursor films with a thickness of 130 nm were formed on silicon substrates by spin coating method. They were annealed at 350°C in remote oxygen plasma at a pressure of 2.0×10−2 Pa and a 13.56×106 Hz radio frequency power of 300 W for 3h followed by 1.3×106-Pa-H2O vapor heating at 260°C for 3 h. Polysilazane precursor films were entirely oxidized by high-pressure H2O vapor heat treatment, and the density of Si-N bonding and Si-H bonding in Polysilazane precursor films were effectively dissociated by the combination of high-pressure H2O vapor heat treatment with remote oxygen plasma treatment. While MOS(Metal-Oxide-semiconductor) capacitors fabricated only by high-pressure H2O vapor heat treatment had a high specific dielectric constant of 6.1, a fixed oxide charge density of 1.3×1012 cm−2 and a density of interface trap of 5.4×1011 cm−2eV−1, the remote oxygen plasma treatment followed by high-pressure H2O vapor heat treatment allowed us to reduce them to 4.1 and 1.6×1011 cm−2, 4.2×1010 cm−2eV−1, respectively.

Surface protection of titanium by Ti5Si3 silicide layer prepared by combination of vapour phase siliconizing and heat treatment

Abstract In this work we proposed a new method for preparation of protective Ti 5 Si 3 silicide layer. The proposed method consisted of two steps: (1) silicon electron beam evaporation and (2) heat treatment. The silicide-modified titanium was subjected to structural examination, hardness profiling and isothermal oxidation tests. The investigations revealed that the proposed surface treatment produces a layer with a thickness of 1–2 μm and hardness of about 1500 HV. The isothermal oxidation tests showed that the layer is highly resistant to oxidation in air even at 900 °C. Its oxidation rate was comparable or even lower than that of some high-temperature γ-TiAl intermetallics oxidized under similar conditions. The oxidation mechanism was discussed in terms of the internal structure and chemical composition of the scales. It was demonstrated that the silicide layer could serve as excellent protection of titanium, Ti-based alloys and intermetallics against the high-temperature oxidation and wear.

Fruit flies: disinfestation, techniques used, possible application to mango

Introduction . The methods of fruit disinfestation against fruit flies use processes (physical methods) which differ according to the export country and fruit which must be disinfested. The term definitions are made clear and the various treatments are presented. Heat treatments . For mango, treatments usable for disinfestation can only utilize heat, because of the strong sensitivity of this fruit to cold temperatures. The heat treatments in general consist of using an immersion in hot water by a system of batches or an uninterrupted bath. These treatments are then followed or not by a fruit fast cooling which can be carried out by ventilation (cold air) or hydrocooling (water). Heat can also be obtained by use of forced hot air or hot vapor, because a higher temperature than 45 °C kills fly eggs and larvae. Microwave treatments . The use of microwaves is also a technique which makes it possible to increase the temperature in the fruit heart. Irradiation . The last possible solution is the use of irradiation, which uses a principle different from the preceding treatments. Conclusion . In comparison with the most current treatments (vapor heat treatment and forced hot-air treatment), the hot water treatment has many advantages: it is easy to implement, it is quick, it kills surface parasitic organisms, it makes it possible to clean the fruit surface and its cost only corresponds to approximately 10% of the cost of one vapor heat treatment. It would thus be recommended for mango disinfestation.

MICROWAVE-VAPOR HEAT DISINFESTATION ON ORIENTAL FRUIT FLY EGGS IN MANGOES

The objective of this research was to develop a microwave-vapor heat treatment (MW-VHT) for mangoes (Mangifera indica L.) cv. Namdokmai Si Thong to disinfest the oriental fruit fly, Bactrocera dorsalis (Hendel). The mortality of oriental fruit fly eggs and quality acceptability characterized by thermal-death-time and thermal-quality-time overlay plots were initially obtained by hot-water immersion. Two treatments within a range of acceptable quality were selected for inoculation experiments to confirm MW-VHT process. The acceptable range was temperature ranging from 46 to 55C with time ranging from 2 to 20 min. The MW-VHT using microwave for preheating followed by vapor for holding processes effectively disinfested oriental fruit fly eggs. Changes in physiochemical properties of mangoes, e.g., color, titratable acid (TA), total soluble solid (TSS), TSS/TA and firmness, of MW-VHT-treated mangoes were not significantly different (P > 0.05) from physiochemical properties of the nontreated mangoes. MW-VHT resulted in less heat damage of mangoes than conventional vapor heat treatment (VHT) and shortened process time more than 90% during the preheating period. MW-VHT also retained equivalent or better lethality of oriental fruit fly eggs than did conventional VHT.

Defect Reduction in Polycrystalline Silicon Thin Films by Heat Treatment with High-Pressure H2O Vapor

We investigated defect reduction in laser crystallized polycrystalline silicon (poly-Si) films by heat treatment with 1.3×106 Pa H2O vapor. The H2O vapor heat treatment at 260 °C for 6 h reduced the spin density in laser crystallized poly-Si films from 2.0×1018 (initial) to 6.5×1016 cm-3. The activation energy of the reaction for defect reduction was 0.26 eV. Photoconductivity under 532 nm light illumination at 100 mW/cm2 was increased from 2.7×10-6 (initial) to 3.3×10-5 S/cm by heat treatment for 1 h. The oxygen concentration in the silicon films was increased by 1.1×1019 cm-3 by heat treatment, although the hydrogen concentration was decreased by 1.4×1020 cm-3. This suggests that oxygen atoms have an important role in defect state reduction in polycrystalline silicon films.