Vinyl Acetate Films Research Articles

Reducing reflection of down-shifting solar cells through scattering by particles

The improvement of down-shifting solar cells through reducing the reflection in short wavelength range by scattering is investigated experimentally and theoretically. Such down-shifting solar cells are fabricated by doping Y2O3 particles into down-shifting ethylene vinyl acetate films with CaAlSiN3:Eu2+ phosphors. Experimental results show that the scattering of Y2O3 particles can reduce the reflection of the down-shifting solar cells in the wavelength below 450 nm. It can be attributed to two reasons. The first is that the backscattering in the short wavelength is weaker than that in the middle and long wavelength. The second is that the scattering by Y2O3 particles allows more light reach the phosphors and increases their absorption. This means that more photons with poor spectral responses can be converted into the photons with better spectral responses. This work provides a way to realize simultaneously strengthening the down-shifting effect and suppressing the phosphor-induced reflection and can be used to further improve the down-shifting solar cells.

Xurography-Enabled Thermally Transferred Carbon Nanomaterial-Based Electrochemical Sensors on Polyethylene Terephthalate-Ethylene Vinyl Acetate Films.

A novel benchtop approach to fabricate xurography-enabled thermally transferred (XTT) carbon nanomaterial-based electrochemical sensors is proposed. Filtered nanomaterial (NM) films were transferred from Teflon filters to polyethylene terephthalate-ethylene vinyl acetate (PET-EVA) substrates by a temperature-driven approach. Customized PET-EVA components were xurographically patterned by a cutting plotter. The smart design of PET-EVA films enabled us to selectively transfer the nanomaterial to the exposed EVA side of the substrate. Hence, the substrate played an active role in selectively controlling where nanomaterial transfer occurred allowing us to design different working electrode geometries. Counter and reference electrodes were integrated by a stencil-printing approach, and the whole device was assembled by thermal lamination. To prove the versatility of the technology, XTT materials were exclusively made of carbon black (XTT-CB), multiwalled carbon nanotubes (XTT-MWCNTs), and single-walled carbon nanotubes (XTT-SWCNTs). Their electrochemical behavior was carefully studied and was found to be highly dependent on the amount and type of NM employed. XTT-SWCNTs were demonstrated to be the best-performing sensors, and they were employed for the determination of l-tyrosine (l-Tyr) in human plasma from tyrosinemia-diagnosed patients. High analytical performance toward l-Tyr (linear range of 0.5-100 μM, LOD = 0.1 μM), interelectrode precision (RSD ip,a = 3%, n = 10; RSD calibration slope = 4%, n = 3), and accurate l-Tyr quantification in plasma samples with low relative errors (≤7%) compared to the clinical declared values were obtained. The proposed benchtop approach is cost-effective and straightforward, does not require sophisticated facilities, and can be potentially employed to develop pure or hybrid nanomaterial-based electrodes.

Of mice and men: Traces of life in the death registries of the 1630 plague in Milano

The death registries of the plague epidemic of 1630, stored at the Archivio di Stato of Milano, have been interrogated via the EVA film technology (ethyl vinyl acetate film studded with crushed strong anion and cation exchangers as well as C8 resins). The EVA diskettes have been left in contact with the lower right margins of 11 different pages pertaining to the peak months of the raging disease (June through end of September) for 60–90min and then the captured material, after elution and digestion, analysed by mass spectrometry. The main findings: 17 Yersiniaceae family proteins, 31 different human keratins, 22 unique mouse keratins, about 400 peptides from different bacterial strains, 58 human tissue proteins and 130 additional mouse and rat tissue proteins. In addition, >60 plant proteins (notably potato, corn, rice, carrot and chickpeas), likely representing the meagre meals of the scribes, contaminating the pages, were detected. The significance of these unique findings is amply illustrated in the body of the article. SignificanceArchivists, historians, librarians usually explore the texts of ancient and modern manuscript in order to extract the meaning of the writing and understand the mood, feelings, political, philosophical and/or religious ideas therein expressed by the authors. With the present EVA methodology (the only one, at present, able to access our Cultural Heritage without damaging or contaminating it) we interrogate, instead, the support, be it paper, parchment, wood panel, cloth, canvas and the like, in order to extract invisible data, such as the presence of drugs, medicaments, infectious pathogens, human and environmental contaminants. Metabolites, proteins and peptides thus captured are then analysed via mass spectrometry. The unique data mined by this technology should considerably enlarge the (so far) restricted horizon of the writing exploration and add new insight on the environmental conditions in which such documents were produced as well as, importantly, on the health/pathological conditions of the authors. It is believed that the present technology, as here reported, will become the officially accepted one for exploring the world Cultural Heritage.

Efficiency of polycrystalline photovoltaic parks in Romania: Possibility of using renewable energy

The performance of photovoltaic panels and lifetime are determined to a large extent by the quality of photovoltaic cells, their soldering technology, the quality of ethyl vinyl acetate film in which they are encapsulated, the encapsulation technology and the back sheet. Depending on the manufacturing technology, photovoltaic panels can be made of monocrystalline, polycrystalline, and amorphous silicon cells. This manuscript studies the main factors that influence the aging of photovoltaic panels in order to assess their effectiveness and sustainability in terms of energy, in order to establish the optimum conditions of photovoltaic panel?s location, being a contribution to the attainment of the targets in terms of growth using renewable sources of energy. The main purpose of this research is to study the current state, in Romania, in the field of renewable energies by using solar panels.

Correlation between Numerical and Experimental Tests of Laminated Glass Panels with Visco-elastic Interlayer

Present research is focused on numerical and experimental investigation of glass laminate structure consolidated with ethylene vinyl acetate film. The European wide industry standard for laminate glass panels is considered polyvinyl butyral interlayer film where ethylene vinyl acetate layer is particular out of autoclave manufacturing process related. Conducted numerical and experimental research worldwide rarely consider this type of polymer in lamination process even though in Baltic‘s this is industry standard. So far such glass laminate products are not mechanically characterised to the level that experimental results correlation with numerical predictions to give an engineers required confidence. Therefore current research initially characterise post cured ethylene vinyl acetate film then integration of viscoelastic material properties in numerical four point bending analysis and finally verification with non-contact measurements of natural frequencies to assess mechanical response of laminate glass panels. It was shown that by introducing non-linear viscoelastic behaviour of ethylene vinyl acetate film for depicting mechanical behaviour in 4-point bending the discrepancy between numerical and experimental results was less than 5% whereas assuming the interlayer as isotropic material only obtained discrepancy reached up to 50%.

Influences of environmental factors on Si-based photovoltaic modules after longtime outdoor exposure by multiple regression analysis

Degradation of Si-based photovoltaic (PV) modules after longtime outdoor exposure is quantitatively investigated using multiple regression analysis. Performance ratios (PR) of the PV modules are primarily influenced not only by irradiation intensity on tilted surface (IrrT), average photon energy (APE), and module temperature (Tmod) but also by angle of incidence (AOI). It is demonstrated that multiple regression analysis allows us to independently and quantitatively identify how each IrrT, APE, Tmod, or AOI (environmental factors) relates to the PR (outcome), thus leading to the understanding of impacts of environmental factors on physical properties of the Si-based PV modules. After longtime outdoor exposure, the influences of IrrT, APE, and AOI on the PR of multi-crystalline (mc-Si) and single-crystalline (c-Si) modules are severely increased, resulting from the decay of interconnection and discoloration of ethylene vinyl acetate films. The dependences of environmental factors on the PR of hydrogenated amorphous (a-Si) modules do not change as much as those on PR of mc-Si and c-Si modules do because of differences in the module structures.

Antioxidant Microemulsion-based Ethylene Vinyl Acetate Film Containing Mangiferin and Surfactants

Mangiferin, a natural antioxidant additive, was incorporated into an ethylene vinyl acetate copolymer (EVA) containing 18% vinyl acetate (VA) using the emulsion solvent evaporation technique. Sorbitan ester (Span ® 20) and polymeric surfactant (Pluronic ® P−123) were compared. Mangiferin was finely dispersed in the suspension with the addition of surfactants studied. Span ® 20 was chosen as the surfactant for film preparation in the next step due to the dispersing and film forming properties. Effects of vinyl acetate (VA) contents on the film properties were investigated. The EVA films with 12% VA had the highest tensile strength and oxygen barrier, followed by 18, 25 and 40% VA, respectively. Addition of Span ® 20 had only a slight effect on mechanical and barrier properties of the films, but markedly increased the release of mangiferin from the EVA matrices except in the 40% VA films. The maximum concentrations of mangiferin released from the 40, 25, 18 and 12% VA films into 95% ethanol were 83.30, 66.84, 51.77 and 34.57 μg·mL −1 1, respectively. The release concentrations from the 40 and 25% VA films was 2.4 and 1.9 folds of that from the 12% VA film, respectively. The antioxidant activity of the EVA films containing mangiferin and Span ® 20 was 80% radical-scavenging capacity (RSC) for the 40 and 25% VA and 60% RSC for the 18 and 12% VA. The release of mangiferin from the EVA matrices may be controlled by appropriate selection of the surfactants and vinyl acetate contents.

Ethylene vinyl acetate films filled with ytterbium containing rare earth particles (Y2SiO5: Ce3+, Yb3+) which have optical down-conversion capabilities and useful for encapsulating solar cells

In order to improve conversion efficiency of crystalline silicon solar cells, optically down-converting encapsulate films were prepared by introducing rare earth particles Y2SiO5: Ce3+, Yb3+ into ethylene vinyl acetate. First, ethylene vinyl acetate and the filler particles (up to 5 wt%) were melt compounded. Then, 0.4-mm thick film samples were made from the compounds with a laminator. Light conversion properties of the ethylene vinyl acetate films were investigated by UV-Vis-NIR spectra and fluorescence spectra. The relationships between the light conversion and the film transmittance were analyzed. The results show that the Y2SiO5: Ce3+, Yb3+-filled films were able to optically down-convert the 457 nm blue-violet light to the 980 nm near-infrared light. Peel strength increased to 31% (from 14.2 N/mm to 18.6 N/mm) and thermal conductivity increased to 31.3% (from 0.220 W/mK to 0.289 W/mK) in the 1 wt% Y2SiO5: Ce3+, Yb3+ film sample along with a slight reduction in transmittance (from 91.1% to 89.0%), as compared to the unfilled ethylene vinyl acetate films. Bulk electrical resistivity at 1 wt% filler decreased slightly to 1.45 × 1015 ohm·cm, as compared to the unfilled ethylene vinyl acetate film (1.03 × 1016 ohm·cm). The results suggested that the prepared films with varying filler contents could be useful both as front encapsulate films and back sheets for solar cell panels.

Fast curing ethylene vinyl acetate films with dual curing agent towards application as encapsulation materials for photovoltaic modules

To speed up curing of ethylene vinyl acetate (EVA) films as encapsulation materials for photovoltaic modules, a dual curing agent of benzoyl peroxide (BPO) and butylperoxy 2-ethylhexyl carbonate (TBEC) was introduced in this work. The experimental results indicated that for the weight ratio of BPO/TBEC of 0.6/2.4, over 80% gel content of EVA was yielded after curing at 130°C for 12 min. Compared with the case of single curing agent, the present one obviously operated at much lower temperature with faster rate. By carefully studying the influence of curing agent proportion and curing con- ditions on gel content of EVA films, as well as rheology and curing kinetics, the mechanism involved was analyzed and ver- ified. The results are believed to be useful for developing new curing system of EVA encapsulation films with improved processability.

Gas barrier and mechanical properties of crosslinked ethylene vinyl acetate nanocomposites

In this research, the effects of crosslinking agent and clay content on the morphology, barrier and mechanical properties of ethylene vinyl acetate-organoclay nanocomposites prepared by solution method were studied. Dicumyl peroxide has been used as crosslinking agent. The morphology of the prepared nanocomposites was investigated using wide-angle X-ray diffraction and transmission electron microscopy. Wide-angle X-ray diffraction and transmission electron microscopyindicated that the prepared nanocomposites had predominantly intercalated morphologies. The obtained results of permeability tests showed that the permeability of ethylene vinyl acetate films dramatically decreases with addition of organoclay and dicumyl peroxide. Mechanical tests showed that tensile modulus and tensile strength of ethylene vinyl acetate increase with addition of organoclay. Furthermore, the mechanical properties of ethylene vinyl acetate nanocomposites significantly improved in presence of crosslinking agent (dicumyl peroxide).

RT-PCR from laser-capture microdissected samples.

AbstractLaser-capture microdissection (LCM) is a powerful method for efficient procurement of defined cell populations from whole tissue sections. It enables the study of cell biology and molecular pathology at the level of DNA, RNA, and protein (1,2,3). The principle of LCM, as applied by the Pixcell system (Arcturus Engineering Inc., Mountain View, CA) comprises a laser beam of variable size that activates a thermoplastic polymer film on a cap placed in direct contact with cell(s) chosen for microdissection. The melted ethylene vinyl acetate film flows into and replaces dehydrated interstitial and cellular compartments, “capturing” targeted cells onto the cap (Fig. 1). The cap is then placed directly in contact with the appropriate isolation buffer in a standard microfuge tube. Laser-capture microdissection: (A) human melanoma sample before microdissection, (B) after microdissection, and (C) the microdissected cells captured onto the cap. KeywordsIsoamyl AlcoholGuanidinium ThiocyanateEthylene Vinyl AcetateGuanidine IsothiocyanateRinse BrieflyThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Photopolymerization kinetics and monomer diffusion in polymer matrix

A direct and non-destructive method for observing reaction kinetics and monomer transport in photopolymers during photopolymerization is presented. This method is based on monitoring a change in intensity of the fluorescence emitted by plasticized vinylacetate film containing fluorescent monomer, N-vinylcarbazole. The film used in the experiments had high optical density at 295 nm. Illumination of one side of the film led to polymerization of the dispersed monomer and reduction of its concentration predominantly near the illuminated surface. Thus, during this photopolymerization reaction, which produces a monomer concentration gradient, the monomer diffuses across the film toward the illuminated surface. Since only the monomer and resulting polymer are fluorescent, an increase in concentration of the polymer near the illuminated surface increases the fluorescence intensity. This increase in fluorescence intensity is used to monitor the photopolymerization kinetics. It is demonstrated here that upon excitation at 295 nm at room temperature the polymerization kinetics of N-vinylcarbazole in a plasticized vinyl acetate film are controlled by N-vinylcarbazole diffusion. The diffusion coefficient for this monomer, as measured in the present work, is 6 × 10 −9 cm 2s −1.

ハウス栽培におけるニホンナシ‘幸水’の果実発育と樹体生理について

The fruit growth and physiological behavior of Japanese pear (Pyrus serotina Rehder) cv. Kosui under plastic were investigated. Treated trees were covered with ethlene vinylacetate film from 13th March to 20th May.The daily maximum temperature and soil temperature under plastic were 2-6°C and 1_??_2°C higher than those in the open field during the treatment period. Budbreak and flowering time were advanced by about 10 days due to a relatively high temperature.First harvest time was on 4th August under plastic and 17th August in the open field. Fruits grown under plastic with GA paste treatment were the largest in all treatments. Shape index (height/width) of the fruit grown under plastic was greater than that in the open field. Patterns of glucose and sorbitol accumulation in fruits grown under plastic were also different from those in the open field.Treated trees had 15% larger leaves and 22% longer shoots than those in the open field and leaf area indices (LAI) were 2.53 and 2.03, respectively. Carbohydrate content in current shoots grown under plastic was lower than that in the open field in autumn. The activities of root respiration under plastic were higher than those in the open field during summer season.

The morphology of ethylene—vinyl acetate emulsion

Direct observation through an electron microscope of the microstructure of an emulsion particle of ethylene—vinyl acetate was done by using a freeze-etching method. The spherical emulsion particle is composed of regular-shaped microspheroids ca. 500 Å in diameter. The structure of the emulsion film was also observed with electron microscopy. The contour of emulsion particles and the constituent microspheroids were visible in the surface of ethylene—vinyl acetate film using partially hydrolyzed poly(vinyl alcohol) as an emulsifier. But no contour was observed in the surface of emulsion film using poly(oxyethylenealkylphenol) as a nonion surface-active agent. Partially hydrolyzed poly(vinyl alcohol), strongly adsorbed on the surface of the microspheroids, prevents the spheroids from deforming upon the film forming process. When a nonionic surface-active agent is used mutual interdiffusion of polymer chains and emulsifier may occur and make the polymer film homogeneous.