Loss Of Brightness Research Articles

Overexpression of a Paenibacillus campinasensis xylanase in Bacillus megaterium and its applications to biobleaching of cotton stalk pulp and saccharification of recycled paper sludge

A xylanase gene (xynG1-1) from Paenibacillus campinasensis G1-1 was expressed in Bacillus megaterium MS941 and a high level of extracellular xylansae activity (304.26IU/mL) was achieved after induction with 0.5% xylose. The purified recombinant xylanase (XynG1-1R) revealed optimal activity at 60°C and pH 7.0 and retained 79% and 81% activity after incubation without substrate at 60°C, pH 5.0 and pH 8.0 for 3h, respectively. Application of XynG1-1R (15IU/g pulp) to cotton stalk pulp bleaching increased brightness by 3.65% over that of the control without the xylanase and reduced the need for chlorine compounds by 50% without loss of brightness and pulp fiber qualities. When XynG1-1R (80IU/g paper sludge) was used in combination with mixed cellulolytic enzymes, the saccharification efficiency of recycled paper sludge was increased by 10%. These results indicated that XynG1-1R is a promising candidate for various industrial applications such as biobleaching and bioenergy conversion.

QUALITY ALTERATIONS DURING STORAGE OF SUGAR-FREE GUAVA JAM WITH ADDED PREBIOTICS

ABSTRACT The aims of this study were as follows: to assess the changes that occur in sugar-free guava (Psidium guajava) jam with added prebiotics during 180 days of storage and to investigate the influence of opaque and transparent packages on the stability of this jam during storage through microbiological, physical, chemical and physicochemical analyses. The packaging influenced the a*, b* and L* color parameters, and the transparent packaging had the greatest loss of brightness and lowest intensity levels of red color when compared with the opaque packaging. The length of storage time significantly affected all variables (color, syneresis, water activity, fructooligosaccharide concentration, titratable acidity and pH). The microbiological quality of the sugar-free guava jam with added prebiotics in both packaging types was maintained for 180 days. PRACTICAL APPLICATIONS The work presented also the creation of healthy and nutritious desserts, combining the taste of marmalade traditional functionality of prebiotics. Nutrition and technology.

Assessment of pulp machine white water quality at market kraft pulp mills

The bleaching of pulp is a significant cost, yet the brightness achieved in the bleaching plant can be diminished in the pulp machine because of white water (WW) quality. Monitoring WW quality can control these losses. A method was developed to assess WW quality that allows differentiation between the effect of fibers, fines, and dissolved solids (DS) in the WW. It was found that the quality of the WW varied greatly from mill to mill. The brightness loss was mainly affected by the presence of fines, through a combination of their concentration and color. The DS were significantly less detrimental to the optical properties of the final furnish. None of the constituents present in the pulp machine WW caused significant brightness reversion (except the hardwood fine fractions). It is therefore recommended that a monitoring procedure for WW quality at the mill site be used to diagnose and prevent the occurrence of brightness problems. Such monitoring offers a way to reduce bleaching costs.

Contrast‐enhanced wide‐angle high‐speed polarization modulator for active‐retarder 3‐D displays

Abstract— A contrast‐enhanced wide‐angle high‐speed polarization modulator for active‐retarder 3‐D displays is proposed. By using a double liquid‐crystal‐cell structure together with a dedicated driving scheme and an external quarter‐wave retarder, a high‐performance modulator can be realized, resulting in minimized brightness loss and low cross‐talk levels in fast‐refresh time‐multiplexed 3‐D displays.

Using a monochromator to improve the resolution in TEM to below 0.5Å. Part I: Creating highly coherent monochromated illumination

Chromatic aberration limits the resolution in spherical-aberration corrected Transmission Electron Microscopy to approximately 0.7Å at 300 kV. The energy spread in the beam is the main contribution to the chromatic aberration. This spread can be reduced with a monochromator. Another limitation to the resolution in TEM can be the finite brightness of the source and the consequent partial spatial coherence of the illumination. This limitation becomes important when spherical aberration and/or defocus are present such as in uncorrected TEM or in focal-series reconstruction in TEM. We used a monochromator optimized for minimum brightness loss and a prototype 'high-brightness' gun, and obtained brightness after monochromation comparable to that of the standard Schottky FEG before monochromation. The images were acquired on the prototype TEAM 0.5 microscope, which was developed on a Titan platform by increasing its electrical and mechanical stability.

New Deinkable Water based Inkjet Inks

Water based inkjet ink is a major challenge for the deinking process. This process is the key step in paper recycling. It has been designed to separate hydrophobic ink particles from hydrophilic cellulose fibers. In this process, soluble dyes cannot be removed; they stay and accumulate in the circulation water. Thus additional bleaching steps have been suggested to make up for the loss in brightness. However, bleach is not an option for the majority of paper mills producing newsprint and other graphic papers from the household mix. It is neither economical nor ecological as this would require to add equipment and to increase the use of chemicals as well as the chemical load of the effluent.Therefore, other solutions look more sustainable: Inkjet inks that help to produce prints which perform as good as offset or dry toner prints in a standard deinking paper mill. Resin based inks seem to be a way to achieve this goal.

Process Optimization for the Biopolishing of Jute Fiberswith Cellulases from Aspergillus Nidulans AJ SU04

The enzyme cellulase of higher activity (49.82 U/ml) from Aspergillus nidulans AJ SU04 was applied for the biopolishing of jute fibers in this study. Application of cellulase in fabric biofinishing is investigated by treating the jute fibers with partially purified cellulase and studying the enhancement of fiber brightness, smoothness and weight loss. The biofinishing conditions including treatment time, fiber to enzyme ratio (concentration), agitation rate and temperature are optimized for a smooth fiber surface. The results of the scanning electron microscope (SEM) analysis, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) favored maximum surface finishing. The optimized conditions for the biopolishing of jute fibers were found to be 45⁰C, PH 5.0 and 17 h of the treatment. The optimum jute fiber concentration was found to be 16% (w/v).

Clinical significance of red target increment perimetry

AbstractPurpose To elucidate the significance of red target increment perimetry in diagnostic and occupational assessmentMethods Red target increment perimetry does not rely on color discrimination but merely on red target detection on a white background. In a retrospective study, ten exemplary cases of congenital and acquired color vision deficiencies are evaluated by kinetic, static and microperimetric techniquesResults Daltonism: Red brightness loss is common to protan observers. In marked protanomaly and protanopia severe constriction of red target field is a rule; i.e. within the peripheral visual field of protan observers red objects may remain entirely undetected. Female carriers of protan defects: Red target fields may show constriction to variable extent, but less pronounced than in male protan observers. Rod monochromacy: Since rhodopsin is virtually unable to absorb red light, red target fields are entirely lacking. Stargardt’s disease and cone dystrophies: Red target fields are affected earlier and more pronounced than standard white fields. Central serous retinopathy: Red desaturation and red brightness loss are common findings on confrontation testing. Scotomas are detected on microperimetry by red targets while white stimuli still fail to pick up pathology. CAR: Cancer associated retinopathy: Compared to RP, in CAR the cone system shows more involvement. CAR scotomas show up more distinctly in red than in white perimetry.Conclusion In congenital protan defects, red target increment fields have a significant bearing on occupational demands. In various retinal diseases, field defects for red target increments exceed those for white targets and so, may contribute to early diagnosis.

8.4: Contrast‐Enhanced High‐Speed Polarization Modulator for Active‐Retarder 3D Displays

AbstractA contrast‐enhanced, high‐speed polarization modulator for active‐retarder 3D displays is proposed. By using a double‐cell structure together with a dedicated driving scheme and an external quarter‐wave retarder, a high‐performance modulator can be realized, resulting in minimized brightness loss and low crosstalk levels in fast‐refresh, time‐multiplexed 3D displays.

Gradient Intensified Alkali Extraction of Kraft Pulp by Oxygen-Containing Bleaching Agents

The selectivity of delignification is disappointing in the conventional intensified alkali extraction by oxygen and H2O2. To improve the properties of the conventional intensified alkali extraction, the gradient intensified alkali extraction by oxygen-containing bleaching agents was presented, and effects of treatment conditions on properties of gradient intensified alkali extraction of kraft pulp by oxygen and/or H2O2 were investigated. In DEPD bleaching sequence, the optimal dosage of H2O2 in EP stage is 1.5% with higher brightness and lower loss in viscosity of bleached pulp. The addition time of H2O2 is better after 20 min of alkali extraction in DE/PD sequence to facilitate bleaching function of H2O2. In DP/ED sequence, the brightness is highest when alkali extraction carried through after 20 min of H2O2 bleaching. In EO stage, the optimal dosage of NaOH is 5.0% considering delignification and bleaching efficiency. As to alkali extraction intensified by oxygen and H2O2, the optimum dosage of H2O2 is 1.0%. Gadient intensified alkali extraction with oxygen and/or H2O2 was adopted for further bleaching and delignification, which can increase the brightness and selectivity of delignification by subtly adjusting the parameters.

Performance of Teak (<i>Tectona grandis</i> L.F) wood on exposure to outdoor weather conditions

The performance of Teak wood on exposure to outdoor weather conditions was investigated. Six even age trees of similar class diameter comprising 15, 20 and 25- year old Teak wood respectively were studied. Wood samples were collected from three points along the tree radial and longitudinal positions. Percentage shrinkage of weathered Teak increased from the tree base to the top and also from the inner wood tothe outer wood for the three age classes. It however decreased with increase in the age of the tree. The mean percentage shrinkage of weathered Teak obtained in the radial directions were 1.51, 1.30 and 0.73% while in the tangential directions, the mean value obtained were 3.14, 2.23 and 1.27% for ages 15, 20 and 25- year old Teakwood respectively. The results of the visual observation of the study samples showed that Teak wood on exposure to outdoor weather condition was resistant to surface splitting and checking in both radial and tangentialdirections. Discolouration and loss of brightness was observed for all the study samples on exposure to outdoor weather conditions irrespective of the tree age and the positions from where the wood sample was collected.Plantation grown Tectona grandis wood of older age classes in Edo State has higher resistance to shrinkage, surface splitting and checking. Its wood is therefore recommended for use as structural material in outdoor weatherconditions @JASEM

Weathering of host rock and corrosion over speleothems in Castañar cave, Spain: an example of a complex meteoric environment

In Castanar cave, weathering processes have been identified on the host rock and speleothems. The result of these processes over speleothems, usually called corrosion, causes the loss of brightness and the formation of a powdery matt outer band. This band is composed by crystals <4 μm that cover the surface of the speleothems and changes the original texture. Corrosion is caused by partial dissolution of the aragonite and calcite that form the speleothems and results in the formation of these small crystals which are not washed away and remain in situ. The presence of similar bands inside and on the surface of the speleothems indicates that corrosion occurs not only at present time, but it has occurred several times interrupting the development of the speleothems. Castanar cave host rock consists of beds of Fe-rich dolomite and magnesite interbedded with greywackes and shales. Weathering of these rocks produces a clay-rich residue of intense red colour formed by quartz, clay minerals and iron oxides and hydroxides. This residue was formed by in situ alteration of the host rock either by dissolution of the dolomite Fe-rich (insoluble residue) or by hydrolysis of some components of greywackes and shales. In touristic caves, the alteration of both speleothems and host rock has usually been related to the acidification of the atmospheric moisture caused by CO2 from the breath of visitors. However, the presence of corrosion lines inside and on the surface of the speleothems and the fact that some of the non-visited galleries of the cave also present alteration features, indicates that this process did also occurred in past times and hence is not related to the presence of visitors. These weathering processes accounted for the outstanding chromatic contrast of the interior of the cave and show that the growth and formation of speleothems cannot be studied without taking weathering into account.

Recent developments in the Deinking of Inkjet and Liquid Toner

For the first time, liquid toner prints in the raw material of a paper mill have caused a significant damage in a recycling paper mill. This incident confirms former lab tests that for the last ten years have pointed at a possible contamination already by small amounts of liquid toner prints.Water based inkjet ink is another challenge for the deinking process. This process has been designed to separate hydrophobic ink particles from hydrophilic cellulose fibers. Soluble dyes cannot be removed as they stay and accumulate in the circulation water. Thus additional bleaching steps have been suggested to make up for the loss in brightness. However, bleach is not an option for the majority of paper mills producing newsprint and other graphic papers from the household mix. It is neither economical nor ecological as one would have to add equipment and increase the use of chemicals as well as the chemical load of the effluent.Therefore, other solutions look more sustainable: inkjet inks that either are not water based or coagulate to form larger, hydrophobic particles on the paper surface. Promising approaches by KAO, Sepiax and Xerox have been tested whether this solution &#x2013; originally intended to improve image quality &#x2013; also helps to match state-of-the-art deinking technology.

Variability in The Natural Termite Resistance of Plantation Teak Wood and its Relations With Wood Extractive Content and Color Properties

Property of natural termite resistance of teak ( T ec tona g r an d i s ) wood signifies one of its most important characteristics. With the purpose of understanding the variation in such resistance, four teak trees in the form of trunk (stem) from Randublatung , Central Java were randomly selected, and each wood portion sampled in radial and axial direction. Extractive content and color properties of the teak wood were also measured and correlated with properties of its natural termite resistance. Bioassay test was conducted by no-choice feeding method using R e t ic u l i t e r m e s spe r a tus Kolbe termites. The extractive contents were determined by successive extraction using n -hexane, ethyl acetate, and methanol, respectively. Color properties were measured with the CIELAB system. Results showed that antitermitic activity of the teak wood was affected by radial and axial position in the corresponding tree. The wood from middle part of the trees in axial direction exhibited the most resistant to termites (mean mass loss = 1- 4 mg ), while in radial direction the sapwood exhibited the least resistance ( greatest mass loss), and moving inward to the near-pith heartwood the resistance tended to decrease somewhat (slight increase of mass loss). Heartwood and sapwood part differed significantly in ethyl acetate and methanol- soluble extractive contents. Apparently, the greater the ethyl-acetate-soluble extractives (EEC) then the higher the termite resistant (lower mass loss), and conversely the greater the methanol- soluble extractive (MEC) then the lower the termite resistant ( greater mass loss). The brightness index (L*) and redness index (a*) varied significantly in radial direction, however, no significant variation was found in color properties within the heartwood. No strong degree correlation was measured between the mass loss due to termite activity and extractive content parameters. In both heartwood and sapwood, a significant negative correlation ( r = -0.50) was found between the mass loss and redness (a*), while correspondingly a significant positive correlation ( r = +0.54) occurred between brightness and mass loss. These occurring phenomena strongly suggested that the red colored teak wood was brought about by the moderately polar EEC (e.g. tannin, quinone, and other polyphenol) that inflicted teak-wood resistance against termite (lower mass loss), while the bright-colored teak wood was due to the highly polar MEC (e.g sugar and other soluble carbohydrate) which were conversely responsible for lowering termite resistance ( greater mass loss).

Cleaning Marble with Ammonium Citrate

Ammonium citrate solutions were tested to determine possible damage on marble using two concentrations, four different values of pH and several variations in application. As pH dropped from values of 10 to 7, marble chips immersed in the solutions showed increasing dissolution of calcite, and polished marble tiles to which solutions had been applied showed increasing loss of gloss and brightness. The least damage to marble tiles was produced when solutions were covered during application, and single cleanings were found to be less damaging than multiple cleanings of the same total application time. Comparison with other cleaning agents – ammonium thioglycolate and ethylenediaminetetraacetic acid (EDTA) – showed that ammonium citrate solutions could be as mild as thioglycolate when used in some conditions, such as high pH and low concentration. In contrast, ammonium citrate solutions could harm the stone significantly when used in other conditions, such as pH 7 or high airflow. In these cases, the damage was nearly as much as a 2% solution of EDTA at pH 10. This study emphasizes the need to develop new cleaning products, research which can only go hand in hand with a better understanding of the various interactions taking place between cleaning agent, substrate and environment.

Enhancing the Photoluminescence of Polymer-Stabilized CdSe/CdS/ZnS Core/Shell/Shell and CdSe/ZnS Core/Shell Quantum Dots in Water through a Chemical-Activation Approach

We report a method for preparing highly photoluminescent, water-soluble CdSe/CdS/ZnS core/shell/shell and CdSe/ZnS core/shell quantum dots (QDs) colloidally stabilized by double hydrophilic copolymers. The polymers, either a diblock copolymer poly(ethylene glycol-b-2-N,N-dimethylaminoethyl methacrylate) (PEG-b-PDMA) or a statistical copolymer poly(oligoethylene glycol methacrylate-co-2-N,N-dimethylaminoethyl methacrylate) (POEG-co-PDMA), were able to replace the hexadecylamine (HDA) or trioctylphosphine oxide (TOPO) ligands on the surface of the as-synthesized QDs and impart water-solubility and colloidal stability to the QD nanocrystals. In water, the [CdSe/ZnS]/POEG-co-PDMA colloids were present in the form of aggregates with a mean apparent hydrodynamic radius Rh of 54 nm and a narrow size distribution. Although the photoluminescence (PL) quantum yield (QY) of the polymer-treated QDs decreased upon transfer from an organic medium to water, much of this loss in brightness could be restored by the addition to the solution of an excess of a water-soluble primary amine such as 3-amino-propanol (APP). This chemical-activation strategy of adding primary amines as PL activators to polymer-stabilized QDs did not lead to a spectral shift of either the absorption or emission of the QDs in water.

Addition of bisulphite to lignin α-carbonyl groups: A study on model compounds and lignin-rich pulp

Abstract Lignin α-carbonyl groups play an important role in light-induced yellowing as initial absorber of UV light. The model compounds vanillin, verataldehyde, and acetovanillone were studied and the reaction rate coefficient k was calculated for the addition of bisulphite to carbonyls. UV-Vis spectra of the model compounds in bisulphite solution were measured between 200 and 400 nm and at a single wavelength of 305 nm. The reaction was fastest with vanillin, but only a minor part of acetovanillone reacted, which can be explained with different reactivity of aldehydes and ketones. Calculated reaction rate coefficients were 26×10-3 s-1 and 18×10-3 s-1 for vanillin and verataldehyde, respectively. Sheets from chemi-thermomechanical pulp (CTMP) were treated with bisulphite solutions (10 mM, 20 mM and 0.1 M; for 1 and 5 min) in order to study the potential of this treatment in retarding yellowing of CTMP. Initial brightness was improved with the treatments, but as the brightness loss was even more drastic, stabilization was not achieved. FT-IR spectra of bisulphite treated samples revealed that only part of the carbonyl groups reacted. The unsuccessful light stabilization of the pulp originated probably from an inadequate carbonyl addition, a problem which could not be resolved.

2‐D/3‐D displays based on switchable lenticulars

Abstract— An attractive concept for 3‐D displays is the one based on LCDs equipped with lenticular lenses. This enables autostereoscopic multiview 3‐D displays without a loss in brightness. A general issue in multiview 3‐D displays is their relatively low spatial resolution because the pixels are divided among the different views. To overcome this problem, we have developed switchable displays, using liquid‐crystal (LC) filled switchable lenticulars. In this way, it is possible to have a high‐brightness 3‐D display capable of fully exploiting the native 2‐D resolution of the underlying LCD. The feasibility of LC‐filled switchable lenticulars was shown in several applications. For applications in which it is advantageous to be able to display 3‐D and 2‐D content simultaneously, a 42‐in. locally switchable prototype having a matrix electrode structure was developed. These displays were realized using cylindrically shaped lenticular lenses in contact with LC. An alternative for these are lenticulars based on gradient‐index (GRIN) LC lenses. Preliminary results for such switchable GRIN lenses are presented as well.

15.1: Improvements Made to the Contrast Ratio of PDPs in a Bright Room by Coating the Phosphors with Pigments

AbstractIn order to improve the contrast ratio of PDPs in the bright room, the reflection luminance of the panel needs to be decreased while the luminance is increased. In this particular process, we decreased the panel reflection by coating the phosphors with pigments of each color. In order to minimize the loss of brightness, we did not coat the green phosphor with its respective pigment. The main reason this was not done was due to the fact that the green phosphor is the most important emission material for the brightness of PDPs, but the green pigment is the most ineffective material in lowering the reflectance. This technique was applied to a 50″ PDP panel. The results showed a contrast ratio increase of 15% without any sacrifice of the luminance by just adjusting the transmittance of the front filter.

Conductor grid optimization for luminance loss reduction in organic light emitting diodes

The recently increased efficiency of organic light emitting devices (OLED) brings lighting applications within reach. If the area of the OLED is of the order a cm2, voltage and brightness losses related to the square resistance of the transparent electrode become important. The homogeneity of the voltage and brightness can be improved by contacting the transparent electrode from all edges and by adding a metallic grid to the transparent electrode. This grid should have narrow lines to minimize transmission losses and improve the total light emission from the OLED. The voltage losses in grids with different shapes (triangular, square, and hexagonal) are evaluated and the grid parameters are optimized to maximize the total light emission. It turns out that a hexagonal grid has lower loss than a square grid with the same line width.