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This research investigates Alumina (Al2O3) and Magnesium nano membrane layers using hybrid technology. Hybrid is a concept of combining two or more materials/elements to achieve something better. Hybrid technology was developed because of the possibility of combining materials/elements which, if used simultaneously, has more advantages than if used independently. The problem to be solved is to find the best composition of Alumina and Magnesium hybrid membranes. Superhydrophobic properties of the membrane are achieved at a percentage of Mg:50 %, Al2O3:50 %. At a composition below 50 % Mg, the small surface roughness has a low surface tension, while the H2 production reaction by Mg is also low, so the surface tension carrying capacity of the gas and the roughness of the droplets is not strong, which causes the hydrophobicity to be low. In compositions above 50 % Mg, H2 production by high Mg makes bubbles cover the roughness peaks so that the surface tension is lower and changes the superhydrophobic to hydrophobic properties. At a high Mg percentage, H2 production is very large, while surface roughness decreases due to minimal Al2O3. As a result, the roughness grooves are unable to accommodate H2 gas bubbles, the bubbles completely cover the roughness peaks which are the source of surface tension so that the hydrophobic properties become hydrophilic. The results of this best hybrid composition can be used as a guide in making superhydrophobic membranes on Alumina (Al2O3) and Magnesium alloys. This membrane application is used as a filtration membrane in the water purification process. Superhydrophobic membranes are widely applied in membrane distillation, membrane gas absorption and pervaporation. [ABSTRACT FROM AUTHOR]

So far, tofu waste application as an electrocatalyst support requires carbonization. This study aims to evaluate porous tofu waste performance as an organic catalyst support without carbonization. The pre-treated tofu waste suspension by acidification using organic oxalic acid was electrolyzed in water solution. Elemental, phase, and morphology characterizations were also performed on tofu waste, supported by digital imaging of tofu waste revealing mesopores and macropores on its structure. The pore area size ranging from 43 to 935 nm2 has been activated by turmeric, thereby increasing the adsorption rate around tofu waste. Methoxyphenyl as an electron donor phenolic compound of turmeric behaves as an ORR agent. Bicnat addition, alkalizing liquid parts of tofu waste suspension, helps to loosen the bonds in water molecules. Pore activation by turmeric and bicnat carbonation synergetically destabilizes water molecule to increase hydrogen production 3-fold. This result is very favorable for converting waste into an alternative energy source. [ABSTRACT FROM AUTHOR]

Purpose: To find out more about the role of hydrogen gas bubbles in improving the hydrophobic nature of a layer, especially in the layers of microparticles Alumina (Al2O3) with Magnesium (Mg). Design/methodology/approach: The method used is an experimental method by first conducting the SEM-Edx test, testing the content of the elements in the waxy layer and observing the topographic shape on the surface of the taro leaves. Then prepare a mixture of Alumina micro particles with Magnesium to investigate the hydrophobicity of the taro leaves. The mixed presentations between Alumina and Magnesium are: (0, 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100%). Findings: The results of this study found three conditions of the Alumina and Magnesium mix layer when in contact with a droplet, namely: Hydrophobic conditions occur when the surface structure of the rough mixed micro layer forms micro crevices, then bubbles of hydrogen gas fill it to form trapped gases. When droplets come in contact with the surface of the mixed layer the effect of the gas being trapped is very effective at creating hydrophobic properties. While the transition conditions occur when more and more hydrogen gas bubbles along with the increasing percentage of Mg and the opposite occurs in micro particle fissures. Bubbles fill the micro-gap space fully so that the tops of the micro particles are covered by bubbles. This causes the droplet surface tension to weaken, so the droplet contact angle decreases. Furthermore, hydrophilic conditions occur when the micro gap is getting narrower as the percentage of Mg increases and the formation of hydrogen gas bubbles increases. The high level of bubble density in the micro gap closes the peaks of the micro particles, which results in the surface tension of the droplet getting weaker. In this weak surface tension condition, the hydrogen bubble can break through the droplet surface tension and change its hydrophobic nature to hydrophilic. Research limitations/implications: This research is limited to the hydrophobicity of Alumina and Magnesium materials, mainly to investigate the role of hydrogen gas in supporting the hydrophobic nature of taro leaves (Colocasia esculenta). Practical implications: The practical implication in this study is the use of hydrophobic membranes which are widely applied to filtration. Originality/value: Discovered the composition of a membrane mixture of Alumina (Al2O3) and Magnesium (Mg) to create hydrophilic and hydrophobic conditions. [ABSTRACT FROM AUTHOR]

The combustion process of Albizia falcataria (AF) sawdust with the addition of natural zeolite (NZ) was observed experimentally using PT 1600 LINSEIS Simultaneous thermal analyzer (STA). The results showed that alkali metal and alkaline metal earth in NZ play an essential role in the process of decomposing the Hemicellulose AF molecule. The results of the molecular analysis show that the chemical balance of the mixture determines the combustion temperature. Excess NZ becomes a thermal burden which slows down the combustion reaction because heat does not sufficiently activate alkali metal and alkaline metal earth in NZ. In a small amount, NZ is less involved in the AF decomposition process. It shows that a mixture of AF and NZ can increase combustion kinetic in the right mix. Addition of 15–20% of NZ decreases the ignition temperature within faster burning rate. Activated alkali metal and alkaline metal earth decompose hemicellulose faster so that they burn completely in minimizing pollutant and maximizing LHV. Greater NZ completes the decomposition much earlier so that at the resting time of the process NZ slightly absorbs heat sinking LHV. The drastic reduction of Ca due to NZ make the fuel is suitable for boiler because Ca is responsible for agglomeration and corrosion. [ABSTRACT FROM AUTHOR]

The development of alternative ecofriendly electric energy production technology is very essential. The development of electric generator by using sea water element to boost electron jump in electrode has been studied. The aim of this research is to develop an electrode material composite that can collaborate with sea water to produce electricity. The electrodes tested are copper, aluminum, activated carbon, wood powder, and graphite electrode powder. The result shows that each electrode produces different voltage when interacting with sea water. It is caused by the patterns of the electron movement disrupted by the electron of sea water in producing a new compound. The composite of graphite-aluminum generates high electricity of about 580 mV compared to other materials. The electrical conductivity of graphite material depends on the particle size which is larger at smaller particle size. This research elucidates the role of sea water elements in boosting kinetic energy of delocalized electron on graphite resulting in an electron jump.

We have investigated the effects of the aspect ratio of the rectangular mesoscale combustor with a narrow slit flame holder on the flame stability limit, flame behavior and uniformity of combustor wall temperature. The combustor was made of copper with a crosssection area of 6 mm2. The combustor aspect ratio (AR) was varied as 1, 1.5, 2.67, and 6. LPG and pure oxygen were premixed and the experiment was conducted at a limited flow rate. Pure oxygen is selected as an oxidizing agent with the intention of revealing in detail the range of flame stability within a very narrow quenching distance. All observed flames were inside the combustion chamber, not outside the channel. This research used a new type of flame holder namely double narrow slit flame holder as a flame stabilizer. The flame holder with double slit and a kind of bluff body in the center helps recirculate the flow and prolong the residence time to make the flame more stable. The use of double narrow slit flame holder successfully extended the stability map to a very lean equivalence ratio (φ), However, there was a dead zone near stoichiometry condition due to very high flame propagation speed. Aspect ratio had an important role for the non-circular combustor. The aspect ratio gave a great effect to determine the limit of the stability map that can be achieved at the rich mixture. The combustor with AR=1.5 had the widest range of flammability limit, while AR=6 had the narrowest flame stability limits. However, the latter reached the most uniform wall temperature, which is important to obtain high efficiency thermal to electric energy conversion. The results of this study can be used to determine the right fuel mixture on the mesoscale combustor as a heat source on the micro power generator/ thermal electric system. [ABSTRACT FROM AUTHOR]

This experiment investigates the effect of backward facing step size variation on combustion stability in the cylindrical meso-scale combustor with the constant contact area. The backward facing step was varied by changing the combustor inlet diameter while the combustor diameter at the combustion zone was kept constant, i.e. has a constant contact area. Butane gas (C4H10) was used as fuel with air as an oxidizing agent. The result shows that the backward facing step has an important role in the combustion stabilization mechanism. Stable flame could be stabilized inside the meso-scale combustor with the backward facing step. Without the backward facing step, the flame blows out, then stable at the combustor rim. Recirculation flow occurs in the area behind the backward facing step. The increasing backward facing step size leads to an increase in reactant inlet velocity, recirculation flow size and shear stress in the area near the backward facing step. At large backward facing step size, the high reactant inlet velocity together with the large shear stress quenches the flame while the heat recovered by recirculation flow is less sufficient to stabilize flame so that the flame drifts to the downstream position. Hence bigger backward facing step size causes narrower flame stability limit area. The smaller the backward facing step size the wider the flame stability limit which shifts more toward lower equivalence ratio and high reactant velocity regions. Decreasing the backward facing step size decreases the reactant velocity into the combustion reaction zone as well as decreases the recirculation flow and the shear stress, so that the quenching effect decreases. The smaller recirculation flow has a better function for the flame holder to increase flame stability inside the meso-scale combustor. Therefore, small backward facing step size has a very important role in recovering heat energy stabilizing the flame in the meso-scale combustor. [ABSTRACT FROM AUTHOR]

The cellular macromolecular and mineralogical content changes during the combustion of Nannochloropsis oculata biomass have been investigated. A Fourier transform infrared spectroscopy (FTIR) analyzer was used to investigate the cellular macromolecular content changes of biomass at every stage of decomposition during heating to 1200 °C. From ambient temperatures to 190 °C, similar spectra were obtained, indicating relatively little change in the chemical structure of the biomass material. Changes in the spectra are very noticeable from 190 to 1200 °C. The combustion process begins with thermal cracking of the ?OH groups of silanol that escape together with moisture at temperatures up to 190 °C. Subsequent temperature increase decreased intensity of the spectrum, indicating thermal degradation of the organic compounds derived from lipids, proteins, and carbohydrates. These processes occur up to 800 °C. The X-ray diffraction (XRD) results showed that the mineral constituents of biomass degraded during the combustion process, and a portion reacted to form new compounds such as melilite (Ca6Na2O15Si4). The SEM images show a morphological distinction between biomass and its residue at 1200 °C, due to the decomposition and rearrangement of the mineral content during heating. Fragmentation of the samples also occurred during heating, characterized by more uniform residue at 1200 °C. [ABSTRACT FROM AUTHOR]

This study aims to experimentally determine the role of intermolecular forces on the contact angle of vegetable oil droplets. Contact angles were recorded using a microscope and measured using digital software. The results show that the surface tension of vegetable oils is influenced by the London force between the electron clouds of molecules. The process of cooling increases vegetable oil contact angles, due to the decreased kinetic energy of constituent molecules and increased London force on the molecules. A decrease in temperature causes the surrounding water vapor to condense, which adheres to the droplet surface (due to the hydrophilic properties of molecules). Hydrogen bonds develop after moisture adheres to the surface. Further, water molecules on the droplet surface reduce the surface tension, because of hydrogen bonds between the molecules on the droplet surface and moisture. Hydrogen bonds among the molecules force water molecules to accumulate on the droplet surface, which suppresses the droplet surface; therefore the contact angle decreases.

The purpose of this study was to evaluate fracture resistance in AISI 304. The J-R curve was constructed from data, which resulted from an impact test by Charpy Impact machine equipped with high-speed sampling rate data acquisition equipment. The critical values of fracture resistance in fusion zones (FZ), high temperature heat affected zones (HTHAZ), low temperature heat affected zones (LTHAZ) and unaffected base metals (UBM) were obtained by calculation methods using some formulas and by graphical methods. Laboratory experiments demonstrated the relationships among the values of energy absorption along the impact test with the obstruction of dislocation movement due to the presence of chromium interstitial solute in all zones and chromium rich carbide precipitates in fusion zones and heat affected zones. [ABSTRACT FROM AUTHOR]

This research intended to investigate combustion of liquid fuel in 3.5 mm inner diameter quartz glass tube mesocombustor, based on liquid film evaporation by using heat recirculation. The mesocombustor has a copper section for heating and evaporating the liquid fuel. In mesocombustor type A, the fuel was glided through the narrow canal in the copper wall while the air was glided through the axial of combustor. The flame could only be successfully stabilized in high-ratio equivalent ranging from ɸ  =1.1 to ɸ=1.6, due to the gap without combustion reaction caused by high air-fuel mixture over the limits of flame stability. Mesocombustor type B, which has annulus-shaped canal, could shift the flame stability from ɸ  =0.8 to ɸ  =1.2; however, it also narrowed the limits of flame stability due to the wall cooling. In mesocombustor type C, both liquid fuel and air were glided through the annulus-shaped canal in the copper wall to fix the fuel evaporation and air mixture. The flame of type C was successfully stabilized, from ɸ  =0.73 to ɸ  =1.48 wider than types A and B. The flame of type C mesocombustor is circle-shaped and fitted to cross section of mesocombustor, but it still has thin gap without any flames due to thermal quenching by the wall. [ABSTRACT FROM AUTHOR]

Surfactants are essential in the pulp recovery process for the removal of ink on paper to be recycled. In order to create a “green” surfactant, seed oil was extracted from Morinda citrifolia L. by Soxhlet extraction for 4–8 h and its composition evaluated by gas chromatography-mass spectrometry (GC-MS). The total ion chromatogram (TIC) of fatty acids of Morinda citrifolia L. (FAMC) indicated that extraction yields the largest amount of unsaturated fatty acids (UFA), specifically C19H34O2 and C21H38O2, at 6 h. All FAMC fractions were evaluated for their suitability as a surfactant for deinking flotation. FAMC isolated after 6 h of extraction yields fatty acids that are the most suitable surfactants, as the fraction consists of mostly unsaturated fatty acids that show good interactions with the structure of common ink molecules. Our results show that the performance of the FAMC taken after 6 h of extraction approaches that of a synthetic surfactant (SS). The appropriate viscous force for deinking flotation was found to be 1.5–2.0 × 10−4 mg/mm s2 when the synthetic surfactant is used compared to 1.0–1.5 × 10−4 mg/mm s2 for FAMC. The higher intermolecular bonding strength in the synthetic surfactant-ink particle system requires higher viscous force. [ABSTRACT FROM AUTHOR]