Atmanto Heru Wibowo

Zinc/Itaconate Coordination Polymers as First Examples with Long-Lasting Phosphorescence Based on Acyclic Ligands

Two novel coordination polymers (CPs) based on zinc(II) and acyclic dicarboxylate linkers, i.e. [Zn2(μ3-IA)2(H2O)4]n (1-W) and {[Zn2(μ-IA)2(DMF)]·H2O}n (2-DMF) (where IA2− = itaconate) have been obtained as a result of a systematic study of some synthetic factors such as pH and solvents, which has allowed optimizing the conditions that render the best yields. 1-W is obtained as X-ray quality single crystals upon which diffraction analysis has been conducted, showing that it consists of a neutral 2D layered structure. Some structural details have been elucidated for 2-DMF based on a comparison of PXRD data with 1-W and in view of the similar composition of both crystalline phases. Photoluminescence (PL) measurements confirm that 2-DMF presents slightly different spectra from those of 1-W. Time-dependent density functional theory (TD-DFT) calculations of 1-W reveal that electronic transitions arise from both first excited singlet and triplet states involving ligand-centred emissions. Moreover, both compounds exhibit blue fluorescence and green phosphorescence that involves less frequent long-lasting phosphorescence (LLP) at 10 K. Exhaustive characterization of long-lasting phosphorescence by means of time-resolved spectroscopy reveals remarkably long lifetimes (τ) of ca. 352 ms (λem ≈ 550 nm) for 1-W and 547 ms (λem ≈ 500 nm) for 2-DMF.

Synthesis and characterization of natural red dye from Caesalpinia sappan linn

The study reports the synthesis and characterization of natural red dye. The dyes were extracted from woods of Caesalpiniasappanlinn at varied temperatures of 70, 80, 90, and 100°C for three hours. The dry wood chips and water at a ratio of 6:1 were immersed in the reactor of 150 liters. The absorbance spectra of the natural red dyes were measured by ultra-violet-visible spectroscopy. Meanwhile, Fourier transform infrared spectroscopy was used to investigate the functional groups of the natural red dyes. In addition, the basic production cost was calculated and the fastness property towards cotton fabrics was investigated according to the Indonesia national standard of 105-C06:2010, 105-B01:2010, and 0288-2008. The results showed that the functional groups found the extracted red dyes indicated the complex bond of brazilein with peak absorbance at a wavelength of 538-540 nm. The extraction temperature also changed the functional group of brazilein. From the color, the absorbance peak, the functional group...

The Effects of plasticizers and palmitic acid toward the properties of the carrageenan Film

Varied plasticizers and palmitic acid additive have been added in the carrageenan film. The film was made by mixing of the carrageenan and plasticizers (glycerol, polyethylene glycol, polyvinyl alcohol) with composition of 92:3, 90:6, 87:9, 84:12, 81:15(%w/w) and in the presence of palmitic acid as additive with 1%, 2%, 3%, 4%, 5% of total weight. Casting method was used for the film molding and drying at 60oC with the oven for 12 hours. To investigate the effects of plasticizers and additive, some mechanical tests on film were performed. The test result concludes that plasticizers in the film decreased the tensile strength and increased the elongation break of the carrageenan film. The additive of palmitic acid decreased the tensile strength of the carrageenan film and also decreased the-the water absorbance of the film. The highest tensile strength of films made was with the formulation of carrageenan: PEG with composition of 92:3 (% w/w). The highest elongation break of the film was for carrageenan:PVA with the composition of 81: 15 (%w/w) and carrageenan:palmitic acid:PEG with the composition of 92: 3: 1 (%w/w). The lowest water absorption of the film was achieved for carrageenan:PVA:palmitic acid with the composition of 87: 3: 5 (%w/w).

Preliminary Study of Bio-Impedance Based Sensor Using Organic Polymer Membrane for Identification of Pork and Beef

Bio-impedance based sensor using organic polymer-membrane was presented in this paper. The Ca-alginate with glycerol as plasticizer used in the experiments was fabricated by slip casting method on a glass substrates. After atmospheric heating treatment of edible films at 60°C for 24 hours, the films-membranes of 50 mm were obtained. Bio-impedance characterizations were carried out by LCR meter at room temperature. The experiment results showed that the sensor finely operated at low frequency i.e. less than 40 kHz. Response of the sensor increased with the increase of samples mass and became constant after a critical mass. Finally, bio-impedance responses of beef and pork were clearly indicated by a different magnitude that it is possible to apply the films-membranes as bio-sensor applications.

Synthesis of Activated Carbon from Coal for Enhancing Hydrogen Content in Syngas from Co-Gasification of Rice Husk and Coal

Hydrogen-rich syngas either from nonrenewable or renewable sources plays a key role for fulfilling the future energy demand. The CO2 sorbent, activated carbon, synthesized from coal was studied and introduced into the process of co-gasification rice husk with coal. The research was conducted in the continuous gasification reactor with a capacity of 5 kg/h. The raw material used was rice husk and coal while the mass concentration of rice husk was varied at 0%, 25%, 50%, 75%, and 100%. The steam as a gasification agent was maintained at temperatures of 400°C and 500°C. The effect of coal, steam temperature, and activated carbon to enrich hydrogen in the syngas was disclosed. The synergistic effect of enhancing hydrogen content in the syngas from the co-gasification was found the mass concentration of coal around 50%. This paper found also the characteristic of activated carbon to increase the concentration of hydrogen in the syngas and the suggestions for improving them were proposed.