scholarly journals Effects of Ultraviolet Radiation on Recycled and Virgin HDPE Corrugated Pipes Used in Road Drainage Systems

2021 ◽  
Author(s):  
Khanh Q. Nguyen ◽  
Patrice Cousin ◽  
Khaled Mohamed ◽  
Mathieu Robert ◽  
Adel El-Safty ◽  
...  
Keyword(s):  
Uv Radiation ◽  
Uv Light ◽  
Morphological Structure ◽  
Tensile Tests ◽  
Repair Process ◽  
Thermomechanical Properties ◽  
Uv Exposure ◽  
Scanning Calorimetry ◽  
Drainage Systems ◽  
Significant Difference

Abstract High-density polyethylene (HDPE) pipe is one of the materials of interest for use in road drainage systems. The combination of ultraviolet (UV) light, temperature, and moisture can produce weak spots and lead to pipe degradation during the storage, installation, and repair process. The objective of this study was to evaluate changes in the chemical, morphological structure, and thermomechanical properties of recycled and virgin pipes under UV exposure. Laboratory accelerated aging tests were conducted by exposing pipes to UV for 3600 hours with an irradiance of 0.89 W/(m2 nm) at a wavelength of 340 nm. A cycle of 12 hours—comprised of 8 hours of UV radiation at 60°C and 4 hours of no UV radiation at 50°C corresponding to no water condensation—was performed to condition the specimens. HDPE specimens were taken out after 3600 hours and analyzed with FTIR (Fourier-transform infrared spectroscopy), SEM (scanning electron microscopy), DSC (differential scanning calorimetry), oxidative-induction time (OIT) measurements, and tensile tests. The results show that the recycled pipes maintained good properties and were not significantly affected by UV radiation, similarly to the virgin pipes. Statistical analysis using one-way analysis of variance (ANOVA) shows that there was no significant difference between tensile strength, elastic modulus, and hardness measurements before and after UV exposure. There were only a few small changes in the surface of the pipes. The addition of carbon black, antioxidants, and UV stabilizers prevented further aging of the pipes during UV exposure.

UV Irradiation of Shell Eggs: Effect on Populations of Aerobes, Molds, and Inoculated Salmonella typhimurium

1997 ◽  
Vol 60 (6) ◽  
pp. 639-643 ◽  
Author(s):  
FUENG-LIN KUO ◽  
JOHN B. CAREY ◽  
STEVEN C. RICKE
Keyword(s):  
Salmonella Typhimurium ◽  
Uv Radiation ◽  
Uv Light ◽  
The Other ◽  
Uv Exposure ◽  
Microbial Populations ◽  
Aerobic Bacteria ◽  
Fluorescent Light ◽  
Uv Treatment ◽  
Shell Eggs

The effects were investigated of 254-nm UV radiation on populations of Salmonella typhimurium, aerobes, and molds on the shells of eggs. In the first experiment, the CFU of attached S. typhimurium cells on unwashed clean shell eggs were determined after 0, 1, 3, 5, and 7 min of UV treatment (620 μW/cm2) on both ends of the egg. All UV treatments significantly reduced S. typhimurium CFU (P < .01). UVtreatment (620 μW/cm2) in 1-min alternating light and dark cycles for 5 min (three light and two dark) was compared to 0, 3, and 5 min of UV treatment. No significant differences in microbial populations were observed among light and dark cycles and the other UV treatments. In a subsequent experiment, the same UV treatments were utilized to evaluate photoreactivation. After UV exposure, eggs were exposed to 1 h of fluorescent light or I h of darkness or cultured immediately. S. typhimurium CFU were significantly (P < .01) reduced by the UV treatments. However, no significant differences between microbial populations exposed to UV treatment and UV radiation plus photoreactivation were detected. For studies of aerobic bacteria and molds, different UV treatment times (0, 15, and 30 min) at the intensity of 620 μW/cm2 and different intensities (620, 1350, and 1720 μW/cm2) for 15 min were evaluated. Mold CFU per egg were either 0 or 1 for all UV treatments and a 99% reduction of CFU of aerobic bacteria per egg were observed for all UV treatments. It appears from these studies that UV light can significantly reduce populations of S. typhimurium, aerobes, and molds on shell eggs.

52 INITIATION OF PREGNANCIES IN SOUTH AFRICAN RIVERINE RABBIT (BUNOLAGUS MONTICULARES) BY INTERSPECIES NUCLEAR TRANSFER USING ADIPOSE-DERIVED SOMATIC CELLS

2008 ◽  
Vol 20 (1) ◽  
pp. 106
Author(s):  
M. J. Sansinena ◽  
D. Owiny ◽  
R. S. Denniston ◽  
D. Salamone ◽  
D. Barry
Keyword(s):  
In Vitro Culture ◽  
Nuclear Transfer ◽  
Uv Light ◽  
Uv Exposure ◽  
Domestic Rabbit ◽  
Donor Cells ◽  
Significant Difference ◽  
Preliminary Study ◽  
Interspecies Nuclear Transfer

The riverine rabbit (Bunolagus monticulares), one of South Africa's most threatened mammals, with an estimated population size under 250, was upgraded from endangered to critically endangered in 2002. The low number of riverine rabbits precludes any attempts of nuclear transfer (NT) using intraspecific oocytes; therefore, the overall aim of this study was to assess the ability of the domestic rabbit (Oryctolagus cuniculus) oocyte to reprogram the somatic cell of the endangered riverine rabbit by interspecies NT. A preliminary study evaluated the effect of timing of enucleation after induction of ovulation (h post-hCG). A second study assessed the effects of two activation protocols. In addition, since the unique characteristics of the rabbit zona pellucida affect the speed of micromanipulation, different exposure periods to UV light at enucleation were evaluated. Adult domestic Californian rabbits were treated with eCG for 72 h, and ovulation was induced by hCG administration. Oocytes were collected by retrograde flushing at 12–14 h or 16–18 h post-hCG administration and stripped of cumulus investments with 0.5% hyaluronidase in Ca-Mg-free PBS. Metaphase-II oocytes were selected by visualizing the first polar body. Oocytes were stained with 2 mg mL–1 Hoechst 33342 for 5 min, and metaphase plates were removed with a 25–30 μm (O.D.) borosilicate beveled, spiked pipette after exposure to <5 or 30–40 s of UV light. Adult adipose-derived riverine rabbit fibroblasts grown to confluency in DMEM with 10% FCS were used as donor cells and fused with 2 consecutive DC pulses (3.2 kV cm–1, 45 μs). After reconstruction, couplets were randomly assigned for activation by either a second set of electrical pulses or incubation with ionomycin, followed by 1 h of incubation in 2 mm 6-DMAP. Embryos were co-cultured with a bovine oviductal cell monolayer in DMEM with 10% FCS and assessed for cleavage after 36 h of in vitro culture. There was a significant difference in the number of cleaved embryos from oocytes collected at 12–14 h post-hCG (n = 50) or 16–18 h post-hCG (n = 51) administration (57% v. 0% cleaved; P < 0.05). No significant difference was detected in embryos developing after electrofusion v. ionomycin activation treatments. However, a significantly greater number (P < 0.05) of embryos cleaved from oocytes exposed to <5 s UV than from oocytes exposed to 30–40 s UV (Table 1). A total of 20 embryos (4-cell to 16-cell stages) were surgically transferred to the oviducts of 4 adult New Zealand white synchronized recipients after 48 h of in vitro culture. Two recipients (<5 s UV exposure treatment group) were diagnosed pregnant by abdominal palpation at 15 days post-transfer; pregnancies were subsequently lost by Day 30, with placental tissues recovered. This preliminary study indicates the domestic rabbit oocyte is capable of reprogramming riverine rabbit donor cells. In addition, the time of oocyte collection after ovulation induction and the UV exposure period during enucleation have an effect on the efficiency of interspecies NT and embryo development in this species. Table 1. Effect of UV exposure during enucleation on the in vitro development of interspecies nuclear transfer riverine rabbit embryos

Patulin Reduction in Apple Juice from Concentrate by UV Radiation and Comparison of Kinetic Degradation Models between Apple Juice and Apple Cider

2012 ◽  
Vol 75 (4) ◽  
pp. 717-724 ◽  
Author(s):  
KITIPONG ASSATARAKUL ◽  
JOHN J. CHUREY ◽  
DAVID C. MANNS ◽  
RANDY W. WOROBO
Keyword(s):  
Uv Radiation ◽  
Kinetic Modeling ◽  
Apple Juice ◽  
Radiation Treatment ◽  
Microbial Inactivation ◽  
Uv Exposure ◽  
Order Kinetic ◽  
Apple Cider ◽  
First Order ◽  
Significant Difference

Patulin, a mycotoxin produced by several genera of fungi, including Byssochlamys, Aspergillus, and Penicillium, has been an important concern in apple cider and apple juice due to its toxicity and health consequences. In this study, the effects of UV on the patulin level, physical and chemical properties, and sensory attributes in apple juice from concentrate were investigated. Kinetic modeling of patulin reduction by UV radiation in apple juice from concentrate was calculated and compared with the degradation rate observed previously in apple cider. From an initial patulin contamination of approximately 1,000 ppb (μg/liter), the UV exposure, ranging from 14.2 mJ/cm2 (one pass) to 99.4 mJ/cm2 (seven passes), was successful in reducing patulin levels by 72.57% ± 2.76% to 5.14% ± 0.70%, respectively. Patulin reduction by UV radiation followed first-order kinetic modeling in a fashion similar to first-order microbial inactivation. An exponential correlation between UV exposure and the percentage of patulin remaining was observed, giving an r2 value of 0.9950. Apple juice was repeatedly exposed to 14.2 mJ/cm2 for each treatment, and patulin levels were significantly decreased when compared with the level obtained with the previous UV exposure treatment. While there were no significant differences in the percentages of titratable acidity and ascorbic acid (P &gt; 0.05), there were minor yet random sampling differences in pH and degrees Brix (1 °Brix is 1 g of sucrose in 100 g of solution; the °Brix represents the soluble solids content of the solution as percentage by weight [%, wt/wt]) (P ≤ 0.05). A significant difference (P ≤ 0.05) in sensory perception for the finished apple juice was detected between the control and the full seven-pass UV radiation treatment using an experienced consumer panel and a triangle test. Patulin reduction by UV radiation from both the current study and a previous study involving apple cider was compared, which showed that both matrices strongly fit a first-order kinetic degradation model. However, the kinetic constant for degradation in apple juice was approximately 5.5 times greater than that observed in an apple cider matrix.

scholarly journals The Effect of UV Exposure on the Service-life of Thermochromic Microcapsules Integrated into the Epoxy Matrix

2021 ◽  
Author(s):  
Olga BULDERBERGA ◽  
Andrey ANISKEVICH
Keyword(s):  
Mechanical Properties ◽  
Service Life ◽  
Epoxy Resin ◽  
Epoxy Matrix ◽  
Uv Light ◽  
Colour Change ◽  
Critical Time ◽  
Tensile Tests ◽  
Uv Exposure ◽  
Exposure Effect

The effect of ultraviolet (UV) exposure on the service-life of thermochromic microcapsules integrated into the epoxy matrix was investigated. The microcapsules of the formaldehyde shell contain the core of thermochromic leuco dye. Seven sets of epoxy resin samples filled with concentrations from 0 to 10 wt.% of microcapsules were investigated. The composite samples were exposed to UV for approximately 1000 h. For the quantitative evaluation of colour change under UV, a fast and simple original procedure based on samples’ image treatment was developed. With the exposure time intervals of 50 h, samples were taken out from the UV light chamber to evaluate the exposure effect on their reversible thermochromic ability and mechanical properties. Periodical evaluation of the UV light effect on mechanical properties during the exposure was performed by microhardness tests. Tensile tests of the samples till the fracture were performed every 200 h. The critical time under the exposure of the UV lamp that destroys the reversible thermochromic reaction of the microcapsules was defined as 200 h. At the same time, it has been found that the mechanical properties of the epoxy resin under the same UV source were not strongly affected after 1000 h of irradiance and changed in the frame of ~ 10 %.

scholarly journals Structural characterisation, citral retention and thermal properties of the inclusion complex of rice starch–lemongrass extract

Food Research ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 873-886
Author(s):  
M.A. Hashim ◽  
F. Yahya ◽  
Y. Hamzah ◽  
Wan Aida W.M. ◽  
K.H. Khalid
Keyword(s):  
Thermal Properties ◽  
Inclusion Complex ◽  
Morphological Structure ◽  
Degree Of Crystallinity ◽  
Rice Starch ◽  
Scanning Calorimetry ◽  
Structural Characterisation ◽  
Freeze Dried ◽  
Significant Difference ◽  
The Stability

The citral compound that contributes to the strong-lemony odour of lemongrass has high volatility and low physicochemical stability. To overcome the problems, the inclusion complex of the encapsulation technique was applied with rice starch as a coating material to improve the stability and protect against any unfavourable reaction. Therefore, this study was conducted to determine the structural characterization, citral retention and thermal properties of native rice starch, gelatinised rice starch, inclusion complex of rice starch–citral compound, and inclusion complex of rice starch–lemongrass extract. Lemongrass extract and standard citral compound were homogenised into rice starch dispersion at 80oC for 15 mins and freeze-dried at −50.0±2.0oC. The formation of the inclusion complex powder was determined using different analyses including morphological structure using the scanning electron microscope, crystallinity structure was determined with X-ray diffractometer, identification and quantification of citral compound using HS-SPME-GC-FID and the thermal properties of inclusion complex analyzed using differential scanning calorimetry. The microstructure of both inclusion complex of rice starch-lemongrass extract and rice starch-citral compound exhibited a laminated multiangular shape with crumble formation together with the characteristics of V-type pattern of crystalline complexes. The low degree of crystallinity of the inclusion complex of rice starch–lemongrass extract obtained high in citral entrapment (29.34±3.13%) with the highest concentration of citral retention (7.33±0.78 ppm). Both inclusion complex of rice starch-citral compound and rice starch-lemongrass extract displayed an endothermic peak at 138oC, which is attributed to an inclusion complex occurrence with significant difference (p<0.05) of enthalpy of 0.44±0.05 J/g and 1.61±0.70 J/g, respectively. These findings showed that rice starch was effective in complexing with aroma compounds in improving the stability and protecting the citral compound of lemongrass extract from any unwanted changes. This inclusion complex should be regarded as an important strategy in designing a novel model of citral compound of lemongrass for food flavouring application.ha

scholarly journals Development of a new poly-ε-caprolactone with low melting point for creating a thermoset mask used in radiation therapy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takahiro Aoyama ◽  
Koichiro Uto ◽  
Hidetoshi Shimizu ◽  
Mitsuhiro Ebara ◽  
Tomoki Kitagawa ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Melting Point ◽  
Crystallization Temperature ◽  
Tensile Tests ◽  
Scanning Calorimetry ◽  
Elongation At Break ◽  
Molecular Weights ◽  
Significant Difference ◽  
The Face ◽  
Deformation Ability

AbstractThis study aimed to develop a poly-ε-caprolactone (PCL) material that has a low melting point while maintaining the deformation ability. The new PCL (abbreviated as 4b45/2b20) was fabricated by mixing two types of PCL with different molecular weights, numbers of branches, and physical properties. To investigate the melting point, crystallization temperature, elastic modulus, and elongation at break for 4b45/2b20 and three commercially available masks, differential scanning calorimetry and tensile tests were performed. The melting point of 4b45/2b20 was 46.0 °C, and that of the commercially available masks was approximately 56.0 °C (55.7 °C–56.5 °C). The elastic modulus at 60 °C of 4b45/2b20 was significantly lower than the commercially available masks (1.1 ± 0.3 MPa and 46.3 ± 5.4 MPa, p = 0.0357). In addition, the elongation at break of 4b45/2b20 were significantly larger than the commercially available masks (275.2 ± 25.0% and 216.0 ± 15.2%, p = 0.0347). The crystallization temperature of 4b45/2b20 (22.1 °C) was clinically acceptable and no significant difference was found in the elastic modulus at 23 °C (253.7 ± 24.3 MPa and 282.0 ± 44.3 MPa, p = 0.4). As a shape memory-based thermoset material, 4b45/2b20 has a low melting point and large deformation ability. In addition, the crystallization temperature and strength are within the clinically acceptable standards. Because masks made using the new PCL material are formed with less pressure on the face than commercially available masks, it is a promising material for making a radiotherapy mask that can reduce the burden on patients.

scholarly journals Photocuring of Epoxidized Cardanol for Biobased Composites with Microfibrillated Cellulose

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3858 ◽  
Author(s):  
Sara Dalle Vacche ◽  
Alessandra Vitale ◽  
Roberta Bongiovanni
Keyword(s):  
Uv Light ◽  
Side Reaction ◽  
Reaction Rates ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Microfibrillated Cellulose ◽  
Green Technology ◽  
Raw Material ◽  
Scanning Calorimetry ◽  
Renewable Raw Material

Cardanol is a natural alkylphenolic compound derived from Cashew NutShell Liquid (CNSL), a non-food annually renewable raw material extracted from cashew nutshells. In the quest for sustainable materials, the curing of biobased monomers and prepolymers with environmentally friendly processes attracts increasing interest. Photopolymerization is considered to be a green technology owing to low energy requirements, room temperature operation with high reaction rates, and absence of solvents. In this work, we study the photocuring of a commercially available epoxidized cardanol, and explore its use in combination with microfibrillated cellulose (MFC) for the fabrication of fully biobased composites. Wet MFC mats were prepared by filtration, and then impregnated with the resin. The impregnated mats were then irradiated with ultraviolet (UV) light. Fourier Transform InfraRed (FT-IR) spectroscopy was used to investigate the photocuring of the epoxidized cardanol, and of the composites. The thermomechanical properties of the composites were assessed by thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. We confirmed that fully cured composites could be obtained, although a high photoinitiator concentration was needed, possibly due to a side reaction of the photoinitiator with MFC.

scholarly journals Preparation and Evaluation of Nanofibrous Hydroxypropyl Cellulose and β-Cyclodextrin Polyurethane Composite Mats

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 754
Author(s):  
Luiza Madalina Gradinaru ◽  
Mihaela Barbalata-Mandru ◽  
Mioara Drobota ◽  
Magdalena Aflori ◽  
Maria Spiridon ◽  
...  
Keyword(s):  
Morphological Structure ◽  
Tensile Tests ◽  
Hydroxypropyl Cellulose ◽  
Scanning Calorimetry ◽  
Electrospinning Technique ◽  
Force Microscopy ◽  
Polyurethane Composite ◽  
Atomic Force ◽  
Potential Applications ◽  
Preparation And Evaluation

A series of nanofibrous composite mats based on polyurethane urea siloxane (PUUS), hydroxypropyl cellulose (HPC) and β-cyclodextrin (β-CD) was prepared using electrospinning technique. PUUS was synthesized by two steps solution polymerization procedure from polytetramethylene ether glycol (PTMEG), dimethylol propionic acid (DMPA), 4,4′-diphenylmethane diisocyanate (MDI) and 1,3-bis-(3-aminopropyl) tetramethyldisiloxane (BATD) as chain extender. Then, the composites were prepared by blending PUUS with HPC or βCD in a ratio of 9:1 (w/w), in 15% dimethylformamide (DMF). The PUUS and PUUS based composite solutions were used for preparation of nanofibrous mats. In order to identify the potential applications, different techniques were used to evaluate the chemical structure (Fourier transform infrared-attenuated total reflectance spectroscopy—FTIR-ATR), morphological structure (Scanning electron microscopy—SEM and Atomic force microscopy—AFM), surface properties (contact angle, dynamic vapors sorption—DVS), mechanical characteristics (tensile tests), thermal (differential scanning calorimetry—DSC) and some preliminary tests for biocompatibility and microbial adhesion.

Evaluation of bisphenol A-based epoxy resin containing multiwalled carbon nanotubes to improve resistance to degradation

2018 ◽  
Vol 53 (21) ◽  
pp. 2981-2991 ◽  
Author(s):  
Sameer A Awad ◽  
Christopher M Fellows ◽  
Seyed S Mahini
Keyword(s):  
Bisphenol A ◽  
Epoxy Resin ◽  
Uv Light ◽  
Tensile Tests ◽  
Diglycidyl Ether ◽  
Accelerated Weathering ◽  
Scanning Calorimetry ◽  
Multiwalled Carbon ◽  
Epoxy Nanocomposite ◽  
Before And After

The influence of exposure to UV light and moisture on the durability of a multiwalled carbon nanotube(MWCNT)/epoxy nanocomposite was investigated. Samples of epoxy resin based on diglycidyl ether of bisphenol A (DGEBA) cured with 2,2,4-trimethylene-1,6-hexadiamine (TMDA), and epoxy nanocomposite containing 0.5% MWCNT were exposed to different accelerated weathering times between one and six months. Changes in surface chemistry, mechanical properties (tensile tests), thermal properties (thermogravimetric analysis and differential scanning calorimetry), and morphology were evaluated before and after exposure to accelerated weathering for a period of up to six months. Epoxy nanocomposite (DGEBA–TMDA/0.5%MWCNT) samples had improved thermal stability and resistance to degradation, compared to epoxy resin (DGEBA–TMDA). The effect of MWCNT at reducing degradation was more pronounced than previously found for resins prepared with hydrogenated DGEBA.

Sorbitol enhances the physicochemical stability of B12 vitamers

2020 ◽  
Vol 90 (5-6) ◽  
pp. 439-447 ◽  
Author(s):  
Andrew Hadinata Lie ◽  
Maria V Chandra-Hioe ◽  
Jayashree Arcot
Keyword(s):  
Ascorbic Acid ◽  
Uv Light ◽  
Heat Exposure ◽  
Water Soluble ◽  
Uv Exposure ◽  
Physicochemical Stability ◽  
Before And After ◽  
The Stability

Abstract. The stability of B12 vitamers is affected by interaction with other water-soluble vitamins, UV light, heat, and pH. This study compared the degradation losses in cyanocobalamin, hydroxocobalamin and methylcobalamin due to the physicochemical exposure before and after the addition of sorbitol. The degradation losses of cyanocobalamin in the presence of increasing concentrations of thiamin and niacin ranged between 6%-13% and added sorbitol significantly prevented the loss of cyanocobalamin (p<0.05). Hydroxocobalamin and methylcobalamin exhibited degradation losses ranging from 24%–26% and 48%–76%, respectively; added sorbitol significantly minimised the loss to 10% and 20%, respectively (p < 0.05). Methylcobalamin was the most susceptible to degradation when co-existing with ascorbic acid, followed by hydroxocobalamin and cyanocobalamin. The presence of ascorbic acid caused the greatest degradation loss in methylcobalamin (70%-76%), which was minimised to 16% with added sorbitol (p < 0.05). Heat exposure (100 °C, 60 minutes) caused a greater loss of cyanocobalamin (38%) than UV exposure (4%). However, degradation losses in hydroxocobalamin and methylcobalamin due to UV and heat exposures were comparable (>30%). At pH 3, methylcobalamin was the most unstable showing 79% degradation loss, which was down to 12% after sorbitol was added (p < 0.05). The losses of cyanocobalamin at pH 3 and pH 9 (~15%) were prevented by adding sorbitol. Addition of sorbitol to hydroxocobalamin at pH 3 and pH 9 reduced the loss by only 6%. The results showed that cyanocobalamin was the most stable, followed by hydroxocobalamin and methylcobalamin. Added sorbitol was sufficient to significantly enhance the stability of cobalamins against degradative agents and conditions.

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