Simple modification of titanium(IV) oxide for the preparation of a reusable photocatalyst

Polymers and organic materials that are exposed to sunlight undergo photooxidation, which leads to deterioration of their physical properties. To allow adequate performance under outdoor conditions, synthetic polymers require additives such as antioxidants and UV absorbers. A major problem with optimising polymer formulations to maximise their working life span is that accelerated weathering tests are empirical. The conditions differ significantly from real weathering situations, and samples require lengthy irradiation period. Degradation may not be apparent in the early stages of exposure, although this is when products such as hydroperoxides are formed which later cause acceleration of oxidation. A simple way of quantifying the number of free radicals presents in organic materials following exposure to light or heat is by measuring chemiluminescence (CL) emission. Most polymers emit CL when they undergo oxidative degradation, and it originates from the bimolecular reaction of macroperoxy radicals which creates an excited carbonyl.

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Vacuum Operation for Overloaded Anaerobic Treatment Systems

Water Science & Technology ◽

10.2166/wst.1989.0213 ◽

1989 ◽

Vol 21 (4-5) ◽

pp. 87-95

Author(s):

J. De Santis ◽

A. A. Friedman

Keyword(s):

Volatile Fatty Acids ◽

Loading Rate ◽

Anaerobic Treatment ◽

Optimum Operating ◽

Operating Pressure ◽

Simple Modification ◽

Anaerobic Reactors ◽

Fixed Film ◽

Solids Retention ◽

High Concentrations

Overloaded anaerobic treatment systems are characterized by high concentrations of volatile fatty acids and molecular hydrogen and poor conversion of primary substrates to methane. Previous experiments with fixed–film reactors indicated that operation with reduced headspace pressures enhanced anaerobic treatment. For these studies, four suspended culture, anaerobic reactors were operated with headspace pressures maintained between 0.5 and 1.0 atm and a solids retention time of 15 days. For lightly loaded systems (0.4 g SCOD/g VSS-day) vacuum operation provided minor treatment improvements. For shock organic loads, vacuum operation proved to be more stable and to support quicker recovery from upset conditions. Based on these studies and a companion set of bioassay tests, it was concluded that: (a) a loading rate of about 1.0 g SCOD/g VSS-day represents a practical loading limit for successful anaerobic treatment, (b) a headspace pressure of approximately 0.75 atm appears to be an optimum operating pressure for anaerobic systems and (c) simple modification to existing systems may provide relief for organically overloaded systems.

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Green synthesized Ag-TiO2 for degradation of organic dye through visible light driven photo-reactor and its kinetics

International Journal of Chemical Reactor Engineering ◽

10.1515/ijcre-2021-0111 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Titikshya Mohapatra ◽

Sakshi Manekar ◽

Vijyendra Kumar Sahu ◽

Ashwini Kumar Soni ◽

Sudip Banerjee ◽

...

Keyword(s):

Visible Light ◽

Mangifera Indica ◽

Band Gap Energy ◽

Photo Degradation ◽

X Ray ◽

Green Approach ◽

Vis Spectroscopy ◽

Rate Of Reaction ◽

Visible Light Driven ◽

Modification Of Titanium

Abstract This study reports a green approach for the modification of titanium dioxide (TiO2) nanoparticles with immobilization of silver nanoparticles. One of the natural sources i.e., Mangifera indica leaf extract was utilized as reducing and capping agent for the fabrication of Ag-TiO2 nanocatalyst. Further, the surface morphology and band-gap energy of prepared Ag-TiO2 were analyzed by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and UV–Vis spectroscopy. Also, it was characterized by X-ray Powder Diffraction (XRD) which provides the information regarding the crystallinity of the Ag-TiO2. Subsequently, photo activity of Ag-TiO2 was investigated for the degradation of methylene blue (MB) dye wastewater through visible light driven photoreactor. The Ag-TiO2 provided highest (68%) of photo-degradation efficiency within 110 min for 7.81 × 10−5 mol/L initial MB concentration at pH 8 by using 0.19 g/L photocatalyst. Further, addition of 10 mM H2O2 boost up the MB photodegradation to 74%. The kinetic study confirmed the MB degradation followed first order rate of reaction.

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Measurements of Loudness Growth in 1/2-Octave Bands for Children and Adults With Normal Hearing

American Journal of Audiology ◽

10.1044/1059-0889(1999/008) ◽

1999 ◽

Vol 8 (1) ◽

pp. 40-46 ◽

Cited By ~ 7

Author(s):

Melisa R. Ellis ◽

Michael K. Wynne

Keyword(s):

Hearing Loss ◽

Hearing Aids ◽

Hearing Aid ◽

Age Groups ◽

Lower Boundary ◽

Normal Hearing ◽

Boundary Values ◽

Simple Modification ◽

Point Data ◽

Loudness Growth

The loudness growth in 1/2-octave bands (LGOB) procedure has been shown previously to provide valid estimates of loudness growth for adults with normal hearing and those with hearing loss (Allen, Hall, & Jeng, 1990), and it has been widely incorporated into fitting strategies for adult hearing aid users by a hearing aid manufacturer. Here, we applied a simple modification of LGOB to children and adults with normal hearing and then compared the loudness growth functions (as obtained from end-point data) between the two age groups. In addition, reliability data obtained within a single session and between test sessions were compared between the two groups. Large differences were observed in the means between the two groups for the lower boundary values, the upper boundary values, and the range between boundaries both within and across all frequencies. The data obtained from children also had greater variance than the adult data. In addition, there was more variability in the data across test sessions for children. Many test-retest differences for children exceeded 10 dB. Adult test-retest differences were generally less than 10 dB. Although the LGOB with the modifications used in this study may be used to measure loudness growth in children, its poor reliability with this age group may limit its clinical use for children with hearing loss. Additional work is needed to explore whether loudness growth measures can be adapted successfully to children and whether these measures contribute worthwhile information for fitting hearing aids to children.

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4D printing of reconfigurable metamaterials and devices

Communications Materials ◽

10.1038/s43246-021-00165-8 ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Teunis van Manen ◽

Shahram Janbaz ◽

Kaspar M. B. Jansen ◽

Amir A. Zadpoor

Keyword(s):

Fused Deposition Modeling ◽

Production Method ◽

Single Step ◽

Layer By Layer ◽

Design Strategies ◽

4D Printing ◽

Large Shift ◽

Simple Modification ◽

3D Shape ◽

Fused Deposition

AbstractShape-shifting materials are a powerful tool for the fabrication of reconfigurable materials. Upon activation, not only a change in their shape but also a large shift in their material properties can be realized. As compared with the 4D printing of 2D-to-3D shape-shifting materials, the 4D printing of reconfigurable (i.e., 3D-to-3D shape-shifting) materials remains challenging. That is caused by the intrinsically 2D nature of the layer-by-layer manner of fabrication, which limits the possible shape-shifting modes of 4D printed reconfigurable materials. Here, we present a single-step production method for the fabrication and programming of 3D-to-3D shape-changing materials, which requires nothing more than a simple modification of widely available fused deposition modeling (FDM) printers. This simple modification allows the printer to print on curved surfaces. We demonstrate how this modified printer can be combined with various design strategies to achieve high levels of complexity and versatility in the 3D-to-3D shape-shifting behavior of our reconfigurable materials and devices. We showcase the potential of the proposed approach for the fabrication of deployable medical devices including deployable bifurcation stents that are otherwise extremely challenging to create.

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Graphene oxide-based rechargeable respiratory masks

Oxford Open Materials Science ◽

10.1093/oxfmat/itab003 ◽

2020 ◽

Vol 1 (1) ◽

Author(s):

Stelbin Peter Figerez ◽

Sudeshna Patra ◽

G Rajalakshmi ◽

Tharangattu N Narayanan

Keyword(s):

Graphene Oxide ◽

Polyvinylidene Fluoride ◽

Occupational Safety ◽

Low Cost ◽

Triboelectric Nanogenerator ◽

Layer System ◽

Retention Capacity ◽

Simple Modification ◽

Nonwoven Fabrics ◽

Mask Design

Abstract Respiratory masks having similar standards of ‘N95’, defined by the US National Institute for Occupational Safety and Health, will be highly sought after, post the current COVID-19 pandemic. Here, such a low-cost (∼$1/mask) mask design having electrostatic rechargeability and filtration efficiency of >95% with a quality factor of ∼20 kPa−1 is demonstrated. This filtration efficacy is for particles of size 300 nm. The tri-layer mask, named PPDFGO tri, contains nylon, modified polypropylene (PPY), and cotton nonwoven fabrics as three layers. The melt-spun PPY, available in a conventional N95 mask, modified with graphene oxide and polyvinylidene fluoride mixture containing paste using a simple solution casting method acts as active filtration layer. The efficacy of this tri-layer system toward triboelectric rechargeability using small mechanical agitations is demonstrated here. These triboelectric nanogenerator (TENG)-assisted membranes have high electrostatic charge retention capacity (∼1 nC/cm2 after 5 days in ambient condition) and high rechargeability even in very humid conditions (>80% RH). A simple but robust permeability measurement set up is also constructed to test these TENG-based membranes, where a flow rate of 30–35 L/min is maintained during the testing. Such a simple modification to the existing mask designs enabling their rechargeability via external mechanical disturbances, with enhanced usability for single use as well as for reuse with decontantamination, will be highly beneficial in the realm of indispensable personal protective equipment.

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A simple modification of real-time sector sonography to monitor percutaneous nephrostomy.

Radiology ◽

10.1148/radiology.146.1.6849054 ◽

1983 ◽

Vol 146 (1) ◽

pp. 232-232 ◽

Cited By ~ 7

Author(s):

R L Dubuisson ◽

R P Eichelberger ◽

T B Jones

Keyword(s):

Real Time ◽

Percutaneous Nephrostomy ◽

Simple Modification ◽

Time Sector

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Realizing poly(ethylene oxide) as a polymer for solid electrolytes in high voltage lithium batteries via simple modification of the cell setup

Materials Advances ◽

10.1039/d1ma00009h ◽

2021 ◽

Author(s):

Lukas Stolz ◽

Gerrit Homann ◽

Martin Winter ◽

Johannes Kasnatscheew

Keyword(s):

Ethylene Oxide ◽

High Voltage ◽

Lithium Batteries ◽

Polymer Electrolytes ◽

Solid Electrolytes ◽

Simple Modification ◽

Poly Ethylene Oxide ◽

Benchmark System ◽

Short Circuits ◽

Poly Ethylene

Cell failure of polymer electrolytes is rather the result of short circuits instead of assumed electrolyte oxidation. A spacer with a constant and defined distance can avoid this failure, thus realize a benchmark system for a more systematic R&D.

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Augmented cerclage wire improves the fixation strength of a two-screw construct for humerus split type greater tuberosity fracture: a biomechanical study

BMC Musculoskeletal Disorders ◽

10.1186/s12891-021-04215-7 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Chao-Jui Chang ◽

Wei-Ren Su ◽

Kai-Lan Hsu ◽

Chih-Kai Hong ◽

Fa-Chuan Kuan ◽

...

Keyword(s):

Screw Fixation ◽

Biomechanical Study ◽

Fixation Strength ◽

Myotendinous Junction ◽

Steel Cable ◽

Simple Modification ◽

Greater Tuberosity ◽

Cerclage Wire ◽

Group A ◽

Group B

Abstract Background Poor functional outcome can result from humeral greater tuberosity (GT) fracture if not treated appropriately. A two-screw construct is commonly used for the surgical treatment of such injury. However, loss of reduction is still a major concern after surgery. To improve the biomechanical strength of screw fixation in GT fractures, we made a simple modification of the two-screw construct by adding a cerclage wire to the two-screw construct. The purpose of this biomechanical study was to analyze the effect of this modification for the fixation of GT fractures. Materials and methods Sixteen fresh-frozen human cadaveric shoulders were used in this study. The fracture models were arbitrarily assigned to one of two fixation methods. Group A (n = 8) was fixed with two threaded cancellous screws with washers. In group B (n = 8), all screws were set using methods identical to group A, with the addition of a cerclage wire. Horizontal traction was applied via a stainless steel cable fixed directly to the myotendinous junction of the supraspinatus muscle. Displacement of the fracture fixation under a pulling force of 100 N/200 N and loading force to construct failure were measured. Results The mean displacements under 100 N and 200 N traction force were both significantly decreased in group B than in group A. (100 N: 1.06 ± 0.12 mm vs. 2.26 ± 0.24 mm, p < 0.001; 200 N: 2.21 ± 0.25 mm vs. 4.94 ± 0.30 mm, p < 0.001) Moreover, the failure load was significantly higher in group B compared with group A. (415 ± 52 N vs.335 ± 47 N, p = 0.01), Conclusions The current biomechanical cadaveric study demonstrated that the two-screw fixation construct augmented with a cerclage wire has higher mechanical performance than the conventional two-screw configuration for the fixation of humeral GT fractures. Trial registration Retrospectively registered.

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Highly Water Dispersible Functionalized Graphene by Thermal Thiol-Ene Click Chemistry

Materials ◽

10.3390/ma14112830 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2830

Author(s):

Farzaneh Farivar ◽

Pei Lay Yap ◽

Tran Thanh Tung ◽

Dusan Losic

Keyword(s):

Click Reaction ◽

High Water ◽

Pristine Graphene ◽

Functionalized Graphene ◽

Specific Chemical ◽

Simple Modification ◽

Water Dispersible ◽

Chemical Hazards ◽

Water Dispersibility ◽

C And N

Functionalization of pristine graphene to achieve high water dispersibility remains as a key obstacle owing to the high hydrophobicity and absence of reactive functional groups on the graphene surface. Herein, a green and simple modification approach to prepare highly dispersible functionalized graphene via thermal thiol-ene click reaction was successfully demonstrated on pristine graphene. Specific chemical functionalities (–COO, –NH2 and –S) on the thiol precursor (L-cysteine ethyl ester) were clicked directly on the sp2 carbon of graphene framework with grafting density of 1 unit L-cysteine per 113 carbon atoms on graphene. This functionalized graphene was confirmed with high atomic content of S (4.79 at % S) as well as the presence of C–S–C and N–H species on the L-cysteine functionalized graphene (FG-CYS). Raman spectroscopy evidently corroborated the modification of graphene to FG-CYS with an increased intensity ratio of D and G band, ID/IG ratio (0.3 to 0.7), full-width at half-maximum of G band, FWHM [G] (20.3 to 35.5) and FWHM [2D] (64.8 to 90.1). The use of ethanol as the reaction solvent instead of common organic solvents minimizes the chemical hazards exposure to humans and the environment. This direct attachment of multifunctional groups on the surface of pristine graphene is highly demanded for graphene ink formulations, coatings, adsorbents, sensors and supercapacitor applications.

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