Search results

The aim of this paper is to examine the effects of light controlling system that combined high refractive particles (n-TiO₂ [titanium dioxide – TiO₂]) and tartrazine lake dye (TL dye) on thickness, flexural strength, flexural modulus and surface details of the 3D-printed resin.

Influences of different concentrations of n-TiO₂ and TL dye in light-cured resin formulations for 3D printing (3DP) application were evaluated, including curing thickness, flexural strength and surface details under scanning electron microscopy.

The polymerization thickness of samples containing both n-TiO₂ and TL dye was lower compared to samples with TL dye solely. Samples containing more n-TiO₂ and more TL dye exhibited lower flexural strength and modulus. Ramp models showed that for samples containing 1 per cent TL dye, when their n-TiO₂ content increased from 1 to 5 per cent, surface laminate structures became sharper. However, when the TL dye content doubled to 2 per cent, the surface laminate structures were indefinite compared to 1 per cent TL dye-containing counterparts.

In visible-light 3DP, light controlling system in cooperate dye with high refractive particles provides better energy distribution and scattering control. High refractive particles, dyes and light exposure time had influenced the surface resolution and mechanical properties of the 3DP products.

The purpose of this study is to develop resin composite materials composed of polycaprolactone (PCL) acrylates and hydroxyapatite (HA) nanoparticles for ultraviolet digital light projection (DLP) three-dimensional (3D) printing technique.

Two PCL-based triacrylates, namely, glycerol-3 caprolactone-triacrylate (Gly-3CL-TA) and glycerol-6 caprolactone-triacrylate (Gly-6CL-TA) were synthesized from ring-opening polymerization of ε-caprolacton monomer in the presence of glycerol and then acrylation was performed using acryloyl chloride. 3D printing resins made of Gly-3CL-TA or Gly-6CL-TA, 5% HA and 3% of photoinitiator 2,4,6-Trimethylbenzoyl-diphenyl-phosphineoxide were then formulated. The surface topography, surface element composition, flexural strength, flexural modulus, cytotoxicity and degradation of the PCL-based scaffolds were then characterized.

Resin composite composed of Gly-3CL-TA or Gly-6CL-TA and 5% (w/w) of HA can be printed by 405 nm DLP 3D printers. The former has lower viscosity and thus can form a more uniform layer-by-layer structure, while the latter exhibited a higher flexural strength and modulus after being printed. Both composite materials are non-cytotoxic and degradable.

This study provides a direction of the formulation of environment-friendly resin composite for DLP 3D printing. Both resin composites have huge potential in tissue engineering applications.

Color Maker is a computer simulation of mixing colorants to generate a resultant true colour on screen. It can be described as the infinite shade card. It has obvious advantages to offer the paint coatings and printing ink industries, which are defined. However, applications can be made for Color Maker in all colour‐using industries. An example is given of its development as an accurate tool in determining true colours on pharmaceutical tablet coatings. Here, it evaluates the colour on the tablet in a three‐dimensional rendering of the colour, and produces what can be termed a three‐dimensional shade card.

Most countries seek to impose control on the chemical treatment of both human and animal food. Some, such as the U.S.A., attempt it by highly detailed regulations, in terms most orthodox and almost psychically specific, which seem most complicated compared with our own simplified food ordinances; other countries, such as many of the newer states, treading cautiously in their virgin fields of law‐making, pass broad, enabling laws, leaving details to be filled in later. Although the object is the same in all countries, it is nothing short of amazing how the pattern of legislation manages to be so divergent, and applied for reasons that are not always apparent. In published regulations and laws, there would seem to be less intent on making a country's food exports conform to the legislative requirements of importing countries than in prescribing standards for its home products; the end results have produced food law chaos, rarely seen in other branches of law. A notable exception, the only one, to these irregular developments, and with particular reference to food additive control, are the common decrees and directives of the European Economic Community, representing the six Common Market countries. Its Council prescribes quality standards for individual foods, specific purity standards for preservatives and other additives which may be used for human consumption, and although this standardisation is only beginning, it deserves study, especially the manner in which the community regulations are enforced.

Reports from the south‐east of England that housewives have been purchasing packets of “ glitter ” consisting of powdered glass, lacquered, coated with silver and sometimes dyed, for the purpose of decorating their cakes makes one wonder seriously whether we Britons are any more of a thinking race than our coloured brethren of London and other large centres, who report has it, consume large quantities of canned cat and dog meat as a sandwich spread. In the first case, although the so‐called “ glitter ” was never prepared for use as a cake decoration, the manufacturers concerned have given an assurance that in future packets will be labelled that the contents are not for eating !

Today's narrowing environment requires new ways of looking at the organic pigments industry. In particular a reconstruction of organic pigments is needed in relation to “TOSCA” the Toxic Substances Control Act (USA), which has swiftly become the issue of the hour.

Reports of a number of countries imposing a limited ban on the use of D.D.T. have appeared from time to time in the B.F.J., but in the last few months, what was a trickle seems to have become an avalanche. In Canada, for example, relatively extensive restrictions apply from January 1st, permitting D.D.T. for insect control in only 12 agricultural crops, compared with 62 previously; there is a reduction of maximum levels for most fruits to 1 ppm. Its cumulative properties in fat are recognized and the present levels of 7 ppm in fat of cattle, sheep and pigs are to remain, but no trace is permitted in milk, butter, cheese, eggs, ice cream, other dairy products, nor potatoes. A U.S. Commission has advised that D.D.T. should be gradually phased out and completely banned in two years' time, followed by the Report of the Advisory Committee on Pesticides and Other Toxic Chemicals recommending withdrawal in Britain of some of the present uses of D.D.T. (also aldrin and dieldrin) on farm crops when an alternative becomes available. Further recommendations include an end to D.D.T. in paints, lacquers, oil‐based sprays and in dry cleaning; and the banning of small retail packs of D.D.T. and dieldrin for home use in connection with moth‐proofing or other insect control. The Report states that “domestic users are often unaware that using such packs involve the risk of contaminating prepared food immediately before it is eaten”.

The aim of this study is to examine the effect of carbonization on the surface and its influence on heavy metal removal by water hyacinth based carbon.

Dried water hyacinth stem was used as precursor to prepare carbon based adsorbent by pyrolysis method. The adsorbent proximate (ash, volatile matter and fixed carbon) and elemental (carbon hydrogen nitrogen sulfur) composition, surface area, pore size distribution, surface chemistry was examined and compared.

The results demonstrated that through carbonization in comparison to dried water hyacinth stem, it increased the surface area (from 58.46 to 328.9 m²/g), pore volume (from 0.01 to 0.07 cc/g), pore size (from 1.44 to 7.557 Å) thus enhancing heavy metal adsorption. The metal adsorption capacity of Cd, Pb and Zn was measured and analyzed through induced coupled plasma-mass spectrometer. At metal concentration of 0.1 mg/l adsorption rate for Cd, Pb and Zn was 99% due to increased large surface area, coupled with large pore size and volume. Furthermore, the adsorbent surface hydroxyl group (OH⁻) enhanced adsorption of positively charged metal ions through electrostatic forces.

It is presumed that not only adsorption with synthetic wastewater but real wastewater samples should be examined to ascertain the viability of adsorbent for commercial application.

There are little or scanty data on the effects of carbonization on water hyacinth stem based carbon and subsequent effects on heavy metal removal in effluents.

This study’s aim is to introduce a high-performance sorbent for the removal of both anionic (Congo red; CR) and cationic (methylene blue; MB) dyes from aqueous solutions.

Sodium silicate is adopted as a substrate for GO and AgNPs with positive charge are used as modifiers. The synthesized nanocomposite is characterized by FTIR, FESEM, EDS, BET and XRD techniques. Then, some of the most effective parameters on the removal of CR and MB dyes such as solution pH, sorbent dose, adsorption equilibrium time, primary dye concentration and salt effect are optimized using the spectrophotometry technique.

The authors successfully achieved notable maximum adsorption capacities (Qmax) of CR and MB, which were 41.15 and 37.04 mg g⁻¹, respectively. The required equilibrium times for maximum efficiency of the developed sorbent were 10 and 15 min for CR and MB dyes, respectively. Adsorption equilibrium data present a good correlation with Langmuir isotherm, with a correlation coefficient of R2 = 0.9924 for CR and R2 = 0.9904 for MB, and kinetic studies prove that the dye adsorption process follows pseudo second-order models (CR R2 = 0.9986 and MB R2 = 0.9967).

The results showed that the proposed mechanism for the function of the developed sorbent in dye adsorption was based on physical and multilayer adsorption for both dyes onto the active sites of non-homogeneous sorbent.

The as-prepared nano-adsorbent has a high ability to remove both cationic and anionic dyes; moreover, to the high efficiency of the adsorbent, it has been tried to make its synthesis steps as simple as possible using inexpensive and available materials.