Surface Peeling Research Articles

MICROSCOPY STUDIES OF THE MORPHOLOGY OF FRUIT OF ´RONGRIEN´ RAMBUTAN METHOD

Rambutan fruit (Nephelium lappaceum L.) rapidly lose visual quality due to rapid desiccation and browning of the spinterns. To understand the cause of spintern browning, anatomy of the fruit pericarp was studied. Rambutan cv. 'Rongrien' was selected for this experiment, because of its wide production and also high export value. Anatomy of the fruit pericarp was observed with a light microscope. 15-20 groups of vascular bundles consisting of xylem, phloem and their associated parenchyma tissue were scattered in the spinterns. The vascular bundles in both spinterns and peel were connected. Furthermore, the vascular bundles were also found in tissue below the peel surface closest to the edible portion, the fresh aril. It is proposed that water moves from the peel to the base of the spinterns base and then to the tips of the spinterns. Water is transpired via the stomata located on the skin and spinterns at rates that are influenced by the density of stomata as shown by Yingsanga et al. (2006).

Laser pressure welding of Al alloy and low C steel

This study was performed to obtain fundamental knowledge concerning the development of laser pressure welding technology for the joining of dissimilar metals. Laser pressure welding of Al alloy A6061 and low C steel SPCC sheets was carried out to investigate the effects of the roller pressure, laser beam scanning speed and irradiation position on the tensile shear and peel strength of welded joints. The interfaces of the joints were observed and analysed by SEM and EDX, and the formation phases on the peeled surfaces were identified with XRD. It was revealed that prevention and suppression of oxidation during welding was extremely important to the production of a sound joint with good mechanical properties. The highest tensile strength and the highest peel strength of joints were obtained at a laser power of 1·8 kW, laser scanning speed of 30 Hz, laser irradiation position at the centreline, roller pressure of more than 245 MPa and welding speed of 0·5 m min−1 in an Ar atmosphere. The fracture occurred not in the welded zone but in the A6061 base alloy specimen.

Osmotically induced trehalose and glycine betaine accumulation improves tolerance to desiccation, survival and efficacy of the postharvest biocontrol agent Pantoea agglomerans EPS125

The application of the biocontrol agent Pantoea agglomerans EPS125 to unwounded fruits was practically ineffective for control of postharvest blue mould caused by Penicillium expansum when the treatment and subsequent wounding and pathogen inoculation were separated by periods of unfavourable conditions. This was due to a rapid decrease in viability of the alocthonous introduced biocontrol agent in the intact peel surface. A system for osmoadaptation of the biocontrol agent was developed by combining saline osmotic stress and osmolyte amendment to the growth medium. Osmoadapted cells accumulated trehalose and glycine betaine (GB) intracellularly and showed a higher tolerance to desiccation than non-osmoadapted cells. Osmoadaptation in NaCl plus GB during inoculum preparation increased considerably survival on the peel surface of apple fruits. This effect was significant under low relative humidity (RH) and fluctuating RH conditions, but was not significant at high RH. Osmoadaptation significantly improved blue mould control under conditions where the standard biological control treatments were ineffective. The rot diameter was significantly reduced in apple fruits which were treated with EPS125 and incubated for several days under low, high or fluctuating RH, followed by wounding and inoculation of P. expansum. Growth of EPS125 with NaCl, either with or without the addition of GB, was an effective osmoadaptation treatment for improving blue mould rot control. However, the addition of GB to the NaCl amended growth medium increased 4–5-fold growth rate and OD of the cultures. This is an advantage for mass production of P. agglomerans EPS125 in a NaCl amended growth medium.

김치생산용 알타리무 전처리가공시스템 개발(II) - 평면형 삭피칼날의 최적형상 -

In this study, peeling test of the Altari radish on kimchi pre-processing system for mechanization was performed with the longitudinal plane peeling type with wider cutting blade than that of the peeled chip's. To determine the optimum cutter shape to match this plane peeling type, the peeling tests depending on variable cutting speed, rake angle and blade angle using the blade with thickness as 2 m and width as 50mm were performed, and the patterns of the peeled chips and peeling resistances were investigated. As the result of the tests, the rake angle of the blade with clean peeled surface of the Altari radish was over <TEX>$45^{\circ}$</TEX>, and the blade angle and rake angle with the minimum peeling resistance was <TEX>$20^{\circ}\;and\;60^{\circ}$</TEX>, respectively. The optimum peeling conditions were; the peeling speed 0.2m/s, blade angle <TEX>$20^{\circ}$</TEX> and the rake angle <TEX>$60^{\circ}$</TEX>, and the peeling resistance of each blade was 15 N.

Surface activated bonding of LCP/Cu for electronic packaging

A lamination technique for liquid crystal polymer (LCP)/Cu was developed for high speed and high performance printed circuit boards (PCB). This approach was accomplished by using a modified surface activated bonding (SAB) process to achieve enhanced adhesion and a smooth interface. Systematic investigation of peel strength of four categories of samples, namely “as bonded”, “annealed”, “Cu-deposited”, and “Cu-deposited and annealed” showed highest peel strength in the “Cu-deposited and annealed” sample. Significant improvements in adhesion were observed in the samples cleaned with argon-radio frequency (Ar-rf) plasma (“as bonded” samples) followed by Cu deposition on LCP, which were heated after bonding in low vacuum pressure at 240∘C (about 70–75 times higher than that of “as bonded”). XPS analyses on peeled surfaces of the “Cu-deposited and annealed” sample reveal bulk fracture in the LCP. Threefold lower loss in conduction of SAB processed laminate than that of conventional heat laminate was most likely due to smooth interface of the SAB processed laminate (surface roughness was ninefold lower than that of conventional heat laminate). A plausible adhesion mechanism of Cu/LCP might be due to bonding of Cu adhesion sites to plasma induced dangling sites of LCP surface, and thermal reconstruction of Cu deposited layers.

ELMs and strike point jumps

If an ELM is a peeling of flux surfaces from the plasma, due to a broken separatrix, current density is lost as well as particles and energy. The fast loss of a current-carrying plasma layer modifies the plasma equilibrium, leading to sudden shifts in the strike points at each ELM, towards the plasma centre. An experimental study of this conjectured model of the ELM has been made at JET, showing that in all cases of Type I ELMs studied, strike point shifts were observed. In two cases studied in detail, the estimated equilibrium changes provoked by flux surface peeling agree qualitatively with the observed strike point shifts.

Structure and formation ofH2Ti3O7nanotubes in an alkali environment

The structure and growth of ${\mathrm{H}}_{2}{\mathrm{Ti}}_{3}{\mathrm{O}}_{7}$-type nanotubes have been studied by first-principle calculations. It is shown that the asymmetry in the distribution of hydrogen on the two sides of the surface layer of a ${\mathrm{H}}_{2}{\mathrm{Ti}}_{3}{\mathrm{O}}_{7}$ crystal plate provides a sufficient driving force for the formation of the ${\mathrm{H}}_{2}{\mathrm{Ti}}_{3}{\mathrm{O}}_{7}$ nanotube. Hydrogen deficiency on one side of the surface layer of a ${\mathrm{H}}_{2}{\mathrm{Ti}}_{3}{\mathrm{O}}_{7}$ plate results in a surface tension that increases with increasing hydrogen deficiency and may eventually overcome the coupling from the layers beneath driving the surface layer to peel off from the crystal plate and roll into a tubular structure. While the radius of the resultant nanotube is determined mainly by the layer coupling energy, the thickness of the tube wall is determined by the residual charges on the peeled surface layer. Both the radius and the wall thickness may in principle be controlled via modifying the layer coupling strength and the net charges on the surface.

Two Universal Regimes of Adhesive Film Peeling

A numerical model describing the process of thin adhesive film peeling off a solid surface is considered. A qualitative distinction between the “microscopic” picture and the notions of the standard theory of adhesion (based on the energy balance) consists in that separate elements of the film peel off the surface along virtually the same trajectory irrespective of the direction of the external force action. A more thorough analysis shows that a fine difference between the scenarios of behavior in the vicinity of the touch point still exists, so that one can speak of two classes of universality, corresponding to α π/2. The results of analysis of the proposed microscopic model allow a more correct macroscopic criterion to be formulated for the adhesive surface peeling.

Finite element analysis about stress and strain of surface peeling in Cu-Fe-P sheet

Finite element analysis about stress and strain of surface peeling in Cu-Fe-P sheet

The effect of Goldbonder on the adhesion between porcelain and pure titanium.

The present study examines the effect of a Goldbonder on the adhesion between titanium and porcelain as measured by the strain energy release rate (G) associated with the interfacial fracture of porcelain and titanium. The influence of surface treatment of titanium prior to Goldbonder application was also examined. The porcelain side of the specimens was notched to the interface with a thin diamond saw, and then a pre-crack was made at the metal-porcelain interface by a special jig. The samples were subjected to a four-point bending test resulting in stable crack extension from which G was calculated. Both the cracked cross-section of interface and peeled fracture surface were examined with scanning electron microscope (SEM). The mean G values were 81.57 +/- 10.34, 46.01 +/- 14.83, and 15.98 +/- 1.76 J m(-2) for the sandblasted surface with the Goldbonder, polished surface with the Goldbonder, and sandblasted surface with the Pastebonder, respectively. The G values revealed significant differences (P < 0.01) between Goldbonder and Pastebonder, and between the sandblasted and polished surfaces with Goldbonder. The SEM photographs and elemental analysis showed that Goldbonder developed both chemical and mechanical bonding to titanium and porcelain.

Acidified peel of litchi fruits selects for postharvestPenicillium decay

Litchi fruits are fumigated after harvest with sulfur dioxide (SO2) to prevent their rapid browning. SO2 blocks enzymatic activity but bleaches the fruits and, if this process is followed by dipping the fruit in dilute hydrochloric acid, the appealing red color is regained. Hot water brushing (HWB) is among the alternative methods that were developed to replace the use of SO2. HWB reduced fungal population size on the surface of the fruit peel after treatment but did not eliminate fruit infection after storage. Whereas untreated fruits were infected with a variety of fungal species,Penicillium sp. was the only fungus that developed on the pericarp after storage in fruits that had been dipped in 1.5M HCl. Fruit treated by HWB followed by handling and storage under sterile conditions suffered greater decay than fruit stored under non-sterile conditions but with more ventilation. APenicillium sp. isolated from litchi grew well in liquid medium acidified to the pH range reported for SO2 and HCl-treated litchi fruits. Morphological analysis identified fungal isolates asP. aurantiogriseum. Internal transcribed spacer sequence analysis of five isolates suggested a sequence similarity toP. commune. Our data support the hypothesis that dipping litchi fruit in hydrochloric acid eliminates infection by common opportunistic fungi and selects forPenicillium species that tolerate low pH.

Study of new protective clothing against SARS using semi-permeable PTFE/PU membrane

Chemicals which may pose a hazard to people upon contact may be in several forms, such as liquid, mist, vapor, etc. The damage caused can range from mild skin diseases to more serious chronic illnesses. Therefore, chemical protective clothing must be used to safe some personal who may be exposed to hazardous chemicals. The use of PTFE/PU membrane for chemical protective clothing is discussed in the article. By means of texturing with organic conductive fiber, and then treating with JAM-Y1 anti-bacteria agent, in the end, treating with the XL-550 waterproof agent, the PET fabric has permanent anti-static, anti-bacteria and waterproof and anti-oil properties. The PTFE/PU protective material is prepared by laminating with PET fabric by paste dot coating, and then coated by PU solution in a direct process. The PU coating agent, DMF and acetone, are used in testing through surface tension and peeling strength measurement. The penetration property of poliomyelitis virus in liquid and animalcule in air of PTFE membrane laminated textile, after being coated by PU solution are measured. The results show that it can separate SARS virus in air and liquid, and WVT is 11496 g/24 hm2. Then it can provide a satisfactory wearing comfort.

SCANNING ELECTRONIC MICROSCOPE - SEM EVALUATION OF EPICUTICULAR WAXES IN ‘TOMMY ATKINS’ MANGO WITH BROWN SPOTS

Mango growers in the region of Petrolina - PE, Brazil, are facing a new problem that is the brown spots that appear in the fruits before harvest. In order to study and characterise the defect, brown spots were examined through Scanning Electronic Microscope (SEM). Tommy Atkins mangoes at harvest maturity usually display a red blush in the peel whose extension vary according to sun exposure among other factors. An attempt was made in this experiment to identify the differences between affected and non-affected fruits and between green and red areas of the peel. A wax-covering layer was seen in the green mango peel. The wax however was in crystalline state, easily breakable and loosening. SEM images showed that although waxes covered the peel surface there were areas of unprotected skin that coincided with the brown spot. In the red peel without spots it could be observed that the breaking (or micro-crack) starts from the stomata. In the red peel with spots waxes did not cover the spot area and stomata were closed.

レーザ圧接法によるアルミニウム合金と低炭素鋼の接合

This paper proposes laser pressure welding technology for joining dissimilar metals. Laser pressure welding of aluminum alloy A6061 and low carbon steel SPCC sheets was carried out by changing the roller pressure. And a YAG laser beam was irradiated on different locations into the wedge of two sheets by a f:θ lens and scanned at various frequencies and patterns using two dimensional scanning mirrors. The tensile shear strength and peel strength of welded joints were measured. The tensile shear and peel test specimens made in Ar gas flows fractured in the A6061 base metal and along welded dissimilar metal interface, respectively. The highest tensile strength and peel strength were obtained at the laser power of 1.8 kW, the laser scanning speed of 30 Hz, the laser irradiation position of centerline, the roller pressured of more than 245 MPa and the welding speed of 0.5 m/min in Ar atmosphere. The interfaces of the joints were analyzed by using SEM and EDX, and the formation phases on the peeled surfaces were analyzed with XRD. It was revealed to be important for the production of a sound joint with high mechanical properties to prevent a welding high temperature part from oxidation.

Measuring Adhesive Performance in Transdermal Delivery Systems

The therapeutic performance of a transdermal delivery system (TDS) can be affected by the quality of contact between the patch and the skin. The adhesion of a TDS to the skin is obtained by using pressure-sensitive adhesives (PSAs), which are defined as adhesives capable of bonding to surfaces with the application of light pressure. The adhesive properties of a TDS can only be fully and correctly characterized by considering the following factors: (i) the property that enables an adhesive to form a bond with the surface of another material upon brief contact and under light pressure (tack); (ii) the resistance of the matrix to flow that could be considered as an expression of the cohesiveness of the matrix itself (creep resistance); and (iii) the force required to peel away a patch from a surface (peel adhesion). In this paper, attention is focused on the most widely used methods for the measurement of TDS adhesive properties in development studies and in the quality control of TDSs. The most critical formulative variables in the development of TDSs are the type and concentration of additives used, the drug loaded, the PSA thickness, the composition and thickness of the backing layer, and the solvent residue. There is a lack of evidence for a relationship between the results obtained in in vitro adhesion tests and the in vivo adhesion performance of TDSs. Therefore, an analysis of the percentage of TDSs that lifted and/or detached during pharmacokinetic and clinical studies should be performed during development studies. No official tests for adhesive strength are currently included in the TDS monographs of the most authoritative pharmacopeias. At present, the medical application of TDS relies on tests standardized by the adhesive tape industry or prescribed in the adhesive tape monographs of US and Japanese Pharmacopoeias, or adaptations of these. The development of new methods is recommended to meet the specific requirements of evaluating TDSs, and to improve the correlation between in vitro tests and in vivo performance.

QUALITY CHARACTERISTICS OF 'HORN OF PLENTY' AND 'MEDALLION' YELLOW SUMMER SQUASH AS A FUNCTION OF THE STORAGE TEMPERATURE

QUALITY CHARACTERISTICS OF 'HORN OF PLENTY' AND 'MEDALLION' YELLOW SUMMER SQUASH AS A FUNCTION OF THE STORAGE TEMPERATURE

Effect of water/water vapor on microstructure and phase stability of (Y0.25Bi0.75)2O3solid electrolytes

Highly conductive cubic (Y0.25Bi0.75)2O3tends to transform to rhombohedral (Y0.25Bi0.75)2O3when annealed at 600°C for more than 200 h. Although the rhombohedral phase of (Y0.25Bi0.75)2O3was known to be the stable phase at temperatures ≤600°C, it was found that the annealed (Y0.25Bi0.75)2O3was not thermodynamically stable in the water-containing environment. From x-ray diffraction and transmission electron microscopy analysis, it was observed that the annealed (Y0.25Bi0.75)2O3easily decomposed into monoclinic α-Bi2O3and yttrium hydroxide at a temperature as low as 50°C. The monoclinic α-Bi2O3further reacted with CO2and formed Bi2O2CO3. Consequently, the annealed (Y0.25Bi0.75)2O3degraded and became flaky powder. Scanning electron microscopy micrographs of water-reacted (Y0.25Bi0.75)2O3also showed surface swelling and peeling. Such surface deterioration was caused by a large volume increase during the water reaction. Similar reaction was also observed when the annealed (Y0.25Bi0.75)2O3was exposed in the humidified air at 300°C. As the temperature was raised to 500°C, little reaction was observed between water vapor and (Y0.25Bi0.75)2O3. The better stability of (Y0.25Bi0.75)2O3at elevated temperature was observed.

Induction of Resistance toPenicillium digitatumin Grapefruit by β-Aminobutyric Acid

β-Aminobutyric acid (BABA), an inducer of pathogen resistance in plants, induced disease resistance in reproductive parts of the plant, such as grapefruit peel tissue. Application of BABA to specific wound sites on the fruit peel surface induced resistance to Penicillium digitatum, the main postharvest pathogen of citrus fruit, in a concentration-dependent manner, being most effective at 20mM, and rather less effective at either higher or lower concentrations. The effect of BABA in inducing resistance to P. digitatum in the fruit peel surface was local and limited to the vicinity (within 1–2cm) of the BABA-treated site. In addition to inducing pathogen resistance, increasing concentrations of BABA (from 1 to 100mM) also exhibited direct antifungal activity and inhibited P. digitatum spore germination and germ tube elongation in vitro. The induction of resistance to P. digitatum by BABA was accompanied by the activation of various pathogen defense responses in grapefruit peel tissue, including activation of chitinase gene expression and protein accumulation after 48h, and an increase in phenylalanine ammonia lyase (PAL) activity after 72h.

The effect of an air-dielectric barrier discharge on the surface properties and peel strength of medical packaging materials

In this paper we report and discuss the effect of air dielectric barrier discharge (DBD) surface treatments on adhesion, using poly(ethylene)/poly(ethylene terephthalate) (PE/PET) film and non-woven PE (Tyvek ®) medical packaging materials. The modification of the surface properties of the treated samples has been studied using X-ray photoelectron spectroscopy (XPS), contact angle and peel strength measurements. The influence of the surface treatment parameters, such as the energy deposited by the discharge, the inter-electrode gap and the treatment time, when related to the surface characteristics, allowed establishment of the relationship between such parameters and the properties of the DBD treated samples. Of the three process variables investigated the duration of the treatment has a statistically significant effect on the surface modification. It was found that very short air-DBD treatment (fractions of a second) markedly and uniformly modify the surface characteristics for both Tyvek ® and PE/PET. The treated materials show remarkable stability with ageing time. Improved adhesion properties, with an increase in the peel strength and a greater adhesive transfer are also observed after DBD treatment. Finally, the surface properties investigated tend to reach a plateau following approximately 1 s of processing.

Effects of rolling and sintering temperature on peel strength of bonding interfaces for Ag/Cu bimetallic strips

Cu/Ag bimetallic strips were prepared by roll bonding in the temperature range 293-873 K and sinter treating in the temperature range 523-1073 K. The interface peel strength was determined and the peeled surface morphology observed. High peel strength is obtained from the excellent metallurgical joint given by solute interdiffusion and matrix recrystallisation under sintering conditions 523-673 K for bimetallic strips rolled at ambient temperature. Sintering in the temperature range 873-1073 K results in reduced peel strength due to increased void formation at the interface, although some local contacts on the mated surface could melt and merge at 1073 K. Low peel strength due to poor metallurgical bonding is obtained if the bimetallic strips are roll bonded at temperatures lower than 623 K. The peel strength dramatically decreases due to the thick oxide layer present between the two strip surfaces when the bimetallic strips are roll bonded at excessively high temperatures.