bluuebunny/crossref_metadata_2025 huggingface dataset:
Intake pressure and brake mean effective pressure analysis on various intake manifold design
Authors: Pahmi A , Hisyam Basri M , Mustaffa M E , Yaakob Y , Sharudin H , Ismail N I , Talib R J
Published: December 2019

The internal combustion engine has an intake system that preparing sufficient charges for the engine cylinder. This study is focused on the effect of different intake geometry on the intake pressure and brake mean effective pressure to correlate volumetric efficiency and brake power performance. Five types of intake geometry are simulated by a one-dimensional computational tool. Through the simulations, it can be found the maximum volumetric efficiency predicted by taper design at 1.15 bar of intake pressure and 12.50 bar of brake mean effective pressure when volumetric efficiency reached to 115% and brake power of 19.5 kW. The baseline intake and bellmouth intake showing intake pressure at 0.91 bar and 0.94 bar except for both single bend intake and s-bend intake indicated 0.92 bar intake pressure and 9.35 bar of brake mean effective pressure. The measurement of intake pressure and brake mean effective pressure over various intake geometry displayed a significant influence on the volumetric efficiency and brake power trend.
Scaling Up of Continuous Mineral Carbonation Reactor for the Production of High Value PCC Products
Authors: Ghaddaffi M N M , Syazwan O M , Syazwan M S M , Aimen I M
Published: December 2019

The concept of supercritical CO2 mineral carbonation reaction was firstly proven and demonstrated in the laboratory scale using a 100cc high pressure PVT recombination chamber. Successful proof of concept led PETRONAS to scale up this reaction by developing a working prototype mineral carbonation reactor with the intention of demonstrating the continuous operation of the supercritical CO2 mineral carbonation process. The setup comprising of a feedstock tank, a high pressure liquid pump, a 0.8L high pressure tubular reactor, injector spray nozzle was thoroughly tested to understand the feasibility and robustness of the prototype reactor design and configuration. Another purpose was to study the effect of varying parameters such as reactor pressure, feedstock injection flow rate and compositional effect of methane in carbon dioxide gas reactant to the properties of the precipitated calcium carbonate produced from this process scheme. In summary, the setup was successful to demonstrate the concept of continuous supercritical mineral carbonation reaction up to 1.5 litre/min feedstock injection flow rate. The effect of reactor working pressure and feedstock injection flow rate was the main factors determining the properties and quality of precipitated calcium carbonate produced. Particle size distribution of the calcium carbonate precipitates produced from this setup averaged approximately 6 microns in size. Other parameters such as gas composition and recycling of carrier fluid sucrose have less effect on the properties of the product.
Computational fluid dynamics simulation to predict the effect of the equivalence ratio on the temperature distribution in a pyrolysis furnace
Authors: Muharam Y , David  , Jose A
Published: December 2019

This research investigated numerically the effect of the equivalence ratio on the temperature distribution in an industrial non-premixed flat flame burner with methane as the fuel. The burner configuration is a wall-fired one to produce a flat flame with a large cross-sectional area to effectively radiate heat to tubes contained in a pyrolysis furnace. The temperature distribution was predicted by using a phenomenological model consisting of mass balance, energy balance and momentum balance with computational fluid dynamics approach. Fluid flow was explained by the k-ε turbulent momentum balance, and the reaction rate was approached to eddy dissipation model. Simulation results show that the change in the equivalence ratios affects the temperature distribution so that this variable needs to be adjusted with certain considerations for pyrolysis process.
Total phenolic content, flavonoid concentration and antioxidant activity of indigenous herbs, Physalis minima linn
Authors: Nurhaslina C R , Mealianny H , Mustapa A N , Mohd Azizi C Y
Published: December 2019

Physalis minima linn is a plant under the Solanaceae family having secondary metabolites with distinct biological activities. The total phenolic, total flavonoid and antioxidant activity on different parts (leaves, whole plant, stem, roots and fruits) of Physalis minima linn were analyzed using Folin-Ciocalteu method, aluminium chloride colorimetric method and 2,2’-diphenyl-1-picrylhydrazyl (DPPH) assay, respectively. Results demonstrated that leaves extract exhibited as the highest value of total phenolic content of 1125.42±14.60 mg of gallic acid (GAE) equivalent per gram of plant (dry extract). The low value of IC50 indicated that leaves, whole plant and fruits can be deemed as a good candidate for natural plant sources of antioxidants with high value of antioxidant activity.
Treatment of tapioca starch wastewater with ozonation and adsorption
Authors: Suryana M D , Salsabila N V , Karamah E F
Published: December 2019

In this research, removal of cyanide and COD in tapioca starch wastewater by ozonation and adsorption using GAC examined. The method effectiveness evaluated from percentage of cyanide and COD degradation and ozone mass balance. Effect of degradation method, pH and ozone dose was determined using synthetic wastewater with initial cyanide concentration of 30 ppm and COD concentration of 1000 ppm. Using ozonation adsorption with pH 10 and ozone generation rate of 303 mg O3/h, 91.75% cyanide and 68.94% COD from synthetic wastewater was removed in 1 hour. Tapioca starch wastewater with cyanide concentration of 8.5 ppm and COD concentration of 4625 ppm treated using the same operating condition. Using this method, 87.06% cyanide and 43.23% COD was removed.
Acoustic emission characteristic for different thicknesses of RC slabs
Authors: Muhammad Sauki M I H , Nor N Md , Juhari N , Endut M Z
Published: December 2019

Acoustic emission (AE) has been widely used for monitoring of the structure performance. However, identification of structure’s characteristic is still limited assess. Hence, this paper presents the characteristic of AE of different thicknesses of reinforced concrete (RC) slabs. Two different thicknesses of grade C25/30 RC slabs which are 125 mm and 175 mm were prepared and designated as S125 and S175, respectively. The slabs were designed based on Eurocode 2 with the size of 500 mm width x 1000 mm length were tested under three-point loading in conjunction with the AE monitoring. The maximum loads of the slabs were identified. The acoustic signal strength was analyzed and discussed. It is found that the maximum load of the RC slabs is increased as the thickness of the slab increases. Moreover, the signal strength of S175 is greater than the S125. Hence, this study is beneficial to provide factual data on the maximum load and AE characteristic of different thicknesses of slab.
Removal of colour using banana stem adsorbent in textile wastewater
Authors: Akbar N A , Sabri S , Abu Bakar A A , Azizan N S
Published: December 2019

The potential use of banana stem adsorbent has been investigated via batch adsorption experiment. A series of batch experiment was carried out to determine the effect of various adsorbent dosage ( 0.2 – 1.4 g) and various contact time ( 15 – 120 minutes). Analysis on adsorption isotherm was done using Langmuir and Freundlich model. In addition to it, the behaviour and mechanism of adsorption was analysed using kinetic model, namely Pseudo-first order and pseudo second order kinetic. The result shows that more than 90% of colour was removed at optimum dosage of 1 g of banana stem adsorbent in 100 mL synthetic dye at optimum contact time of 90 minutes. Analysis of isotherm models showed that the adsorption of colour by banana stem adsorbent was fitted to Freundlich with coefficient of determination, r1 of 0.917. Adsorption kinetics of colour showed that Pseudo-second order fit better (r2 = 0.99) than Pseudo-first order (r2 = 0.94) kinetic model. From the result, it was indicated that the adsorption of colour occurred by multilayer on a heterogeneous surface of the banana stem through the chemical reaction process. As a conclusion, the use of banana stem adsorbent has good potential for colour removal in textile wastewater treatment because of low cost of the media. Thus, it is an alternative to overcome problems related to an excessive of colour in dye wastewater treatment plant.
Performance of porous asphalt pavement using clay brick dust as mineral filler
Authors: Joohari M I , Aziz N A , Daud N M , Mansor S , Abdul Halim M A
Published: December 2019

High demand of recycling waste materials are able to solve disposal problem which created opportunities for researcher to use it in their product. Waste clay brick dust is one of the material can be improvised to be tested for the performance of porous asphalt pavement towards rutting problem. In this study, crushed dust of clay brick was used in porous asphalt mixture as mineral filler. 15 samples were produced in different proportions (4%, 4.5%, 5%, 5.5% and 6%) of bitumen content and each proportion have three samples. The optimum bitumen content (OBC) obtained was 4.75% for modified and 5.9% for conventional porous asphalt. Rutting Test was then tested to evaluate the performance of porous asphalt after being modified with clay dust and compared with conventional mixture of porous asphalt. Modified mixture showed a slight higher in rutting depth of 2.2 mm compared to the conventional mixture of 1.6 mm. This means that modified mixture is less in rutting strength. However, the drain down test showed that modified samples are more intact between binder and aggregate and able to sustain in high temperature. Further modifications are required to enhance rutting strength for modified mixture.
Preparation of activated carbon from palm kernel shell by chemical activation and its application for β-carotene adsorption in crude palm oil
Authors: Hidayu A R , Sukor M Z , Mohammad N F , Elham O S J , Azri N I , Azhar M A I , Jalil M J
Published: December 2019

The losses of β-carotene in crude palm oil (CPO) during bleaching process in the industry of oleo chemical bring apprehension because β-carotene is the most important vitamin A precursor that can helps to prevent night blindness, eye problems and skin disorders, and could enhance immunity and protects against toxins, colds, flu and infections.Yet, recovery of β-carotene can be done by adsorption using activated carbon. Accordingly, the study aimed to prepare activated carbon from palm kernel shell (PKSAC) by chemical activation and its application for β-carotene adsorption in CPO has been examined. Activation of palm kernel shell carbon was done chemically using Zinc Chloride (ZnCl2) at impregnation ratio of 1:1 mass basis for 24 hours and carbonization was done at 500 °C for 30 min, 60 min, 90 min respectively called as PKSAC30, PKSAC60 and PKSAC90. PKSAC are characterized using ultimate analysis, Fourier Transform Infrared (FTIR) analysis and scanning electron microscopy (SEM). The capability of PKSAC to adsorb β-carotene was studied using n-hexane as a solvent. β-carotene adsorption test was carried out in a lab-scale batch adsorption reactor. SEM and FTIR analysis result revealed the PKSAC has fibrous morphology and indicates that raw PKS was successfully converted to carbon after activation process and was proven by spectra of previous researchers. For adsorption testing, PKSAC90 give the highest percentage removal of β-carotene, 69%.
Comparative study of acid-treated and alkali-treated carbonised Kapok–fibres for oil/water absorption system
Authors: Abdullah M , Mohd Azlin Shah N A F N , Mohamed Saadun M A A , Kadiran K A , Zaiton S N ‘A , Azman H A , Othman Z S , Osman M S
Published: December 2019

Kapok predominantly utilized as an adsorbent in removing wastewater such as dye, oil and heavy metals. However, a comparative study between acid-treated and alkali-treated carbonized Kapok fibers has not been carried out in detail. In this study, as-made Kapok fibers were carbonized and subsequently undergo acid (HCL) and alkali (NaOH) treatment. The resultant treated Kapok fibers were characterized using Fourier transform infrared (FTIR) spectroscopy, Elemental Analyzer (EA) and Thermogravimetric Analysis (TGA). As-made carbonized Kapok fibers were tested with oil/water absorption model system. A reduction of band intensity at 1740 cm−1 and 1245 cm−1 occurred for NaOH treated sample compared with HCL. The composition of carbon in Kapok fiber increased after carbonization treatment using NaOH (62.42%) and HCL (66.15%) compared with untreated (0.17%). For oil/water absorption system, the result indicated that HCL-treated Kapok fibre was the highest absorption on 28.10 gg−1 diesel, 27.28 gg−1 petrol and 39.84 gg−1 for used vegetable oil respectively in comparison with NaoH-treated and as-made carbonized Kapor fibers. In conclusion, modification of the surface of carbonized Kapok fibers could significantly alter its textural properties which could enhance its oil absorptive behavior.
Water-in-oil-in-water (W/O/W) emulsion instability in emulsion liquid membrane: membrane breakage
Authors: Shah Buddin M M H , Mohd Noor Salizan N D S , Ahmad A L , Elham O S J , Rashidi A R
Published: December 2019

Water-in-oil-in-water (W/O/W) emulsion system in Emulsion liquid Membrane (ELM) consist of three main phases which are membrane phase, internal phase and external phase. However, ELM performance is reported to be heavily affected by the emulsion stability. Instability of emulsions occurred as a result of metastable colloids that are made of two immiscible liquids, where one being dispersed in the other with the presence of surface-active agent. Membrane breakage was identified as one of the causes of emulsion instability. This research work focuses on identifying best condition that records minimal breakage hence, high efficiency of solute removal can be anticipated. Influence of homogenization time and speed, carrier concentration and surfactant concentration on membrane breakage were investigated. Data recorded shows that the emulsion needs to be homogenized at 8000 rpm for 15 mins to obtain minimal breakage of membrane. On top of that, membrane phase consists of 4 wt% of carrier (D2EHPA) and 4 wt% of surfactant (Span 80) dissolved in kerosene is needed. 0.14% of breakage was recorded at the conditions mentioned.
Stabilisation of soft soil using palm oil fuel ash and palm oil fibre
Authors: Lim S Y , Shakri M S
Published: December 2019

Development requires new findings and innovative science to support. This research aims to study the simulation of soft ground improvement by comparing the soil strength after mixing with pozzolanic and fibrous additive such as Palm Oil Fuel Ash (POFA) and Palm Oil Fibre (POF) were chosen due to its redundancy found as industrial waste material. The soft soil sample collected was added with 0%, 5%, 10%, 15% and 20% percentage of additives by weight respectively. The soil sample used was from the soil that passed through sieve size of 0.425 mm. The data and analysis show that POF treated soil has a higher optimum moisture content and greater shear strength than the POFA treated soil.
Temperature regulation for distillation process using self-tuning fuzzy plus PID controller
Authors: Suhaime N F A , Muhammad Z , Yusoff Z M , Leh N A M , Hashim M H C , Zaki M A
Published: December 2019

This paper presents a self-tuning fuzzy logic controller plus PID controller that applied for essential oil extraction process. The most popular technique in extraction essential oil is using steam distillation. This method is lack to the process requirement and also towards parameter change. In order to regulate the steam distillation at desired extraction condition, the controller needs to integrate to the plant. By using auto regressive model with external input (ARX) model structure, the temperature of steam was successfully modelled with best fit 98.42%. This model was successfully representing the system during controller simulation work. There are several controllers that demonstrated in this project which are self-tuning fuzzy PID controller (STFPID) and conventional PID. Both controller will compare their performance in terms of system response which are percent overshoot (%OS), settling time (Ts) and also rise time (Tr). As the result, the STFPID with seven membership function gives the best performance compared to PID controller.
Comparative evaluation on rheology performance and thermal stability of ester based drilling fluids
Authors: Mohamad Daud A R , Abdullah S , Azizi A , Ariyanto E
Published: December 2019

Drilling fluid plays an important role in ensuring smooth drilling operations. Application of ester based drilling fluid (EBDF) is desirable as it shows comparable performance to the conventional oil based drilling fluid (OBDF) as well as environmental friendly. The ester used as a base in the EBDF is usually derived from vegetable oils such as palm oil. In this study, methyl laurate (ML), methyl palmitate (MP), and isopropyl laurate (IPL) esters were used as a base in the EBDF formulation. Subsequently, their physical and rheological properties were determined. In addition, thermal stability of the EBDF was tested to estimate the maximum operating temperature for the EBDF application. Isopropyl laurate (IPL) based EDBF was found to have better rheological properties at standard test condition as compared to the other two esters used. The IPL based EBDF also showed improved viscosity at 90°C. Thermal stability test conducted on the IPL drilling fluid indicated that it is stable up to 150°C.
Characterizations of poly-lactic acid/polypropylene filled with bamboo charcoal powder
Authors: Engku Zawawi E Z , Amirrudin M , Kamarun D , Bonnia N N , Rozana M D
Published: December 2019

In this study, polymer blend was prepared in the ratio of Polypropylene (PP) to Polylactic acid (PLA) of 70:30 by weight. Bamboo charcoal powder (BC), at different loading was added to identify its potential use as filler for the PP/PLA blend. The polymer blend and composites were prepared by using a twin screw extruder. The effects of BC content on the mechanical and thermal properties of the PP/PLA blend were investigated. The results of tensile strength and Izod impact strength show a significant decreased with the addition of BC content. The Young modulus of composites was significantly increased (80%) with the addition of 20 wt.% BC content. The SEM results of composites with 20 wt.% BC filler show a brittle fracture surface. TGA results revealed that, blending PP with PLA cause an increase in thermal stability of PLA. However, the incorporation of 20 wt.% BC has shifted the temperature of initial weight loss of PP/PLA blend towards lower temperature. DSC measurement indicates that the melting temperature (Tm) values of the PP/PLA blend decrease with the addition of 20 wt% BC content, from 169 to 164 °C.
Adsorption study of acrylamide-tertiary-butyl sulfonate (ATBS)/ acrylamide copolymer in polymer flooding enhanced oil recovery (EOR) process
Authors: Sazali R A , Roslan M S , Jarrahian K
Published: December 2019

Polymer flood is known as the most important enhanced oil recovery technology due to its various advantageous and relatively cheaper price. However, it comes with associated problems of polymer adsorption that leads to injectivity loss. This work aims in studying various parameters that may affect the ATBS/ Acrylamide copolymer adsorption in a porous medium to optimize the polymer scheme. Synthetic D brine with D sand sample was mixed and tested in static and dynamic condition. These tests were conducted at room temperature and 90°C whereby the core flooding experiments were conducted with varied flowrate through Berea Sand Core sample. Results show that a higher brine salinity and a longer aging time leads to higher adsorption rate whereas adsorption static test conducted at replicated reservoir condition of 90°C resulted in lower adsorption capacity than at room temperature. Also, static adsorption was found to be higher than the dynamic adsorption due to the changes in the specific surface area and the extent of mechanical retention present in the dynamic core flood experiment. In conclusion, the type of polymer used in polymer flooding must be carefully chosen to serve the need for a specific reservoir condition so that the adsorption phenomenon is minimized.
Extraction of copper ions from aqueous solutions with oleic acid as green solvent
Authors: Halim S F A , Chang S H , Ahmad S K N
Published: December 2019

This research aimed to extract copper ions from aqueous solutions with oleic acid as a green solvent. The effects of pH equilibrium, temperature, and sodium sulphate (Na2SO4) concentration were investigated and the optimum conditions for maximum extraction of copper ions were determined. The findings revealed that the extraction of copper ions increased with equilibrium pH and temperature before it reached a plateau, while it increased and achieved a peak before it decreased with sodium salt concentration. The highest extraction of copper ions was achieved at 94% under the following optimum conditions: equilibrium pH of 4, temperature 55°C and 400 mM of Na2SO4. Therefore, it can be concluded that oleic acid is a potential green solvent for extracting copper ions from aqueous solutions.
Effect of MgO on characterizations and mechanical properties of red soil as oxygen carrier in chemical looping combustion
Authors: Selvarajoo K , Afandi N F , Manap A , Zainuddin R A , Mahalingam S , Kadir N F
Published: December 2019

Red soil is a type of soil that rich in iron and abundantly can be found in Malaysia. However, the application of red soil is limited to agriculture, building blocks, road building and waste water treatment. Chemical looping combustion (CLC) is one of the carbon-capturing technology, in which oxygen from oxygen carrier reacts with fuel inside fuel reactor to produce pure CO2 and H2O. In this research, effect of MgO as supported material was investigated in order to produce desired oxygen carrier from red soil. The composition of 95:05, 90:10, 80:20 and 70:30 of red soil and MgO, respectively, was varied in this research. The phase analysis, morphology, surface area and pore volume size were investigated using X-ray, Field Emission Scanning Electron Microscopy (FESEM) and Brunauer-Emmett-Teller (BET) analysis, respectively. From this study, composition of 90:10 of red soil and MgO, respectively, was found to have high surface area which is 56.95 m2/g with pore volume size of 0.145 cm3/g, and has low crystallite size which favourable as oxygen carrier.
Decolorization of Acid Red 1 using natural zeolite via heterogeneous fenton-like oxidation
Authors: Hassan H , Zahidi M M
Published: December 2019

Fenton process can be regarded as powerful and effective method in decolorization and mineralization of dye pollutants. However, this method is restricted with the generation of iron waste sludge which require secondary treatment. This limitation can be overcome by utilizing heterogeneous Fenton process where iron ions are immobilized onto the catalyst support. In the present study, the heterogeneous Fenton-like oxidation using Fe-natural zeolite (Fe-NZ) was investigated in decolorization of azo dye Acid Red 1 (AR1). The effects of iron ions loading, catalyst dose and initial pH on the decolorization of AR1 were evaluated. The maximum decolorization efficiency of 99.60% was achieved at 0.80 wt% of iron ions loading, 5.0 g/L of catalyst dose, and at 2.5 initial pH. The Fe-NZ showed high catalytic performance for decolorization of AR1 and could be regarded as a suitable low-cost catalyst in heterogeneous Fenton-like reaction.
Characterization of energy content in food waste by using thermogravimetric analyser (TGA) and elemental analyser (CHNS-O)
Authors: Ahmad N , Sahrin N , Talib N , Abdul Ghani FS
Published: December 2019

Food waste samples from various categories were examined for their energy content. In this work, the objective was to characterize the energy contents in food waste to assess their potential for renewable energy resources. The food waste samples that were analysed included tofu, carrot, corn, chicken, biscuit, rice and beef. The food wastes were characterized by proximate analysis using Thermogravimetric Analyser (TGA) and by ultimate analysis using Elemental Analyser (CHNS-O). The energy content in food waste was then evaluated using various higher heating value (HHV) correlations that were researched and established by many researchers. The results from both analyses demonstrated that the energy content from the higher heating value (HHV) calculated by using different equations indicated the food waste usage as an energy source. The highest HHV was found in the beef. Among the samples prepared, it can be observed that the most efficient ‘waste-to-energy’ sample is the protein-based food because this food has the highest amount of volatile matter with the lowest amount of ash content and fixed carbon content. Plus, protein food gives the highest percentages of carbon and hydrogen elements in order to help the combustion process going perfectly in order to convert it into an energy source.
Effect of organic antifoam’s concentrations on filtration performance
Authors: Mohamad Pauzi S , Anak Halbert D , Azizi S , Ahmad N A A , Ahmad N , Marpani F
Published: December 2019

The use of membranes is widely common in bioprocess industry to separate constituents of a liquid, especially during cell clarification process. Many has opted for normal flow filtration mode for this process due to the ease of handling of this technique as compared to tangential flow filtration. Meanwhile, antifoams are chemicals used in upstream process to eliminate the formation of foam throughout the course. It is normally used in conjunction with a nutrient rich broth that is used as a media to cultivate the cells. Some has claimed that antifoam may lead to premature membrane fouling, but some reported that the presence of antifoam may assist and improve the flux rate of the filtration process. This study investigates the effects of organic antifoam presence in a cell-free media on the performance of the filtration process, specifically normal flow filtration process. It was discovered that the presence of organic antifoam may be significant at 1.0% concentration of antifoam loaded in the sample which gives filtration capacity of 250L/m2 while filtration capacity was reported to be at 330L/m2 for samples containing 0.2% and 0.6% antifoam concentration. The flux rate profile has lower percentage reduction that ranges from 18% to 33% which resulted to final flux rate of approximately 700 – 800LMH for initial flux rate of 1000LMH and 27% to 46% reduction that lead to final flux rate of approximately 1000 – 1500 LMH for initial flux rate of 2000LMH.
Characteristics of chromium based mixed oxide catalyst in biodiesel production
Authors: Ali Bashah N A , Luin A , Jalaluddin I A , Shahhaizad I A , Ismail N F , Wan Kamis W Z
Published: December 2019

Renewable energy from biodiesel or fatty acid methyl ester (FAME) has become important in recent decades as one of the promising alternative for petroleum-derived fuel. In this study, chromium based mixed oxide catalysts which are Cr/Ca oxide and Cr/Zn oxide were synthesized via precipitation method and used in the transesterification of cooking palm oil to produce FAME. The reactions were conducted in a batch reactor at temperature of 60 °C, methanol:oil molar ratio of 6:1 and catalyst loading of 1wt%. The characterization through N2 adsorption-desorption showed BET-surface area, pore volume and pore size of Cr/Ca oxide are 3.6915 m2/g, 0.00684 cm3/g and 93.919Å, respectively while for Cr/Zn oxide are 3.9897 m2/g, 0.00630 cm3/g and 80.113Å, respectively. Both catalysts showed similar type isotherm which are type IV and hysterisis loop H3. The catalyst Cr/Ca oxide is found to be more active in the transesterication whereby FAME content of 27.8% was achieved compared to 7.4% by utilizing Cr/Zn oxide. The results showed that Cr/Ca oxide catalyst and Cr/Zn oxide have potential as heterogeneous catalyst to produce FAME from palm oil.
Sonocatalytic degradation of caffeine using CeO2 catalyst: parametric and reusability studies
Authors: Nur Fadzeelah A K , Abdullah A Z , Zubir N A , Abd Razak A H , Azha N A
Published: December 2019

This work examined sonocatalytic degradation of caffeine in the presence of CeO2 prepared by hydrothermal method. Several characterization techniques were used to study the CeO2 including TEM, XRD and BET method. Effects of various parameters such as pH, initial concentration of caffeine and dosage of CeO2 were investigated. This study also examined the reusability of CeO2. Results showed that the CeO2 had mixed shapes of crystallites consisting of rods and cubes with the specific surface area (Sbet) and pore volume of 126.63 m2/g and 0.4898 cm3/g, respectively. About 95.5% of caffeine degradation was achieved under the best parameter conditions i.e. at pH of 7.5, 5.0 mg/L of initial concentration of caffeine and 1.0 g/L of CeO2 dosage within 150 min. It was also revealed that the operating parameters played major roles in caffeine degradation efficiency. In addition, the CeO2 were quite stable since the efficiency of caffeine degradation achieved in the third cycle was 81.4%.
The effect of fibre loading on the physical and mechanical properties of Pineapple Leaf Fibre-reinforced biodegradable composites
Authors: Razali N , Aseri N A S , Dalingam S , Kamarolzaman A A
Published: December 2019

Recently, research on the development of biodegradable material were performed. However, biodegradable materials have a crucial weakness in terms of mechanical properties, but it can be improved by adding reinforcement material as filler. In this study, Pineapple Leaf Fibre(PALF) was chosen as filler due to its many advantages, such as low cost, variety and redundant sources and bio-degradable. The objective of this research is to investigate the effect of PALF fibre loading to the corn starch composites in terms of physical, mechanical and morphological properties. The samples were prepared at different fibre loadings: 5 wt%, to70 wt %, and were fabricated by using the hot press machine. The result showed that physical properties, such as density, water absorption and moisture content, were affected by different fibre loadings. Mechanical properties of the composite samples showed that PALF with 30 wt% gave the optimum tensile strength and modulus. Morphological analysis, composite samples of 30 wt% PALF fibre loading had fewer gaps between matrix and fibre. It can be concluded that 30 wt% of fibre loading is the optimum fibre loading for 3cm length PALF as compared to other composition ratios.
High resolution time domain reflectometry and coaxial cable for soil nail monitoring
Authors: Ng W K , Ashaari Y , Norshazrul M Y
Published: December 2019

Soil nailing is a popular application in soil slope stabilization. Failure of soil nailing could be mainly due to the issue of installation such as inaccuracy of actual length of the soil nail and integrity of cement grout annulus during grouting. This study focuses on using non-destructive technique of time domain reflectrometry (TDR) to monitor the quality of soil nail. TDR is originally used to detect changes in geometry and electromagnetic properties (dielectric or magnetic) happening along its transmission cable and detect the damage or leakage from the cable. The objective of this study is to use high resolution TDR and coaxial cable to detect changes of grout condition in soil nail. Results confirm the suitability of high resolution TDR and coaxial cable to detect void length which relates to grout condition in soil nail. The findings conclude that high resolution TDR model T631 and coaxial cable type RG-6 are capable to detect even small size void and is suitable to be applied for soil nail monitoring.
Dynamics of quantized rings and loops after reconnection in superfluid helium
Authors: Andryushchenko V A
Published: December 2019

The presented work is devoted to the study of the motion of vortex loops after reconnection in superfluid helium. The helium temperature as well as the initial arrangement of the vortex loops varied. The data on the change in the length, average radius of curvature and velocity of vortex loops from the moment of reconnection to the moment of their collapse were obtained. A comparative analysis of the motion of a single vortex ring and a deformed vortex loop was carried out. All calculations were performed within the framework of the vortex filament method using the full Biot-Savard equation.
Large eddy simulation of the vortex breakdown in a turbulent swirling jet
Authors: Borynyak K I
Published: December 2019

The paper presents the results of Large eddy simulation of a free swirling jet with Reynolds number Re = 104 for different swirl numbers. The swirl is organized via the rotation of the nozzle. The case has been divided onto two parts: rotating tube with honeycomb section using dynamic mesh and jet simulation with rotating nozzle using the initial conditions obtained in first part. Simulations were carried for six swirl numbers: 0, 0.15, 0.225, 0.3, 0.46, 0.63. The vortex breakdown with a central recirculation zone formation is observed in the last case.
Harmonic frequency analysis in turbulent double-cavity flow
Authors: Goltsman A E , Saushin I I
Published: December 2019

Flow structure in a turbulent double-cavity flow was reported previously by Goltsman et al. (Physics of Fluids (2019) 31:6) as part I. The results of harmonic frequency analysis of the flow regimes in double symmetric cavities for a wide range of shape factor and Reynolds number based on the cavity length were obtained experimentally and numerically. The frequencies and amplitudes of the main harmonics of the oscillogram were determined; the fields of the Strouhal number and the relative amplitudes of the main harmonic were presented.
Modelling of pulverized coal injection combustion process in the validation test rig using the Euler-Lagrangian approach
Authors: Koshelev K B , Strijhak S V
Published: December 2019

The combustion of pulverized coal is widely used in ironmaking blast furnaces. The pulverized coal has become a very important fuel. Most of the combustion models for the domain zone blast furnaces are based on CFD-LPT approach. In the Eulerian-Lagrangian approach, the continuous phase is treated as a continuum by solving the Navier-Stokes equations and the conservation equations for mass momentum and heat; the dispersed phase is calculated by tracking a large number of particles that follow Newton second law. The coalChemistryFoam solver was used to calculate the flow parameters in the test blast furnace combustion chamber (validation test rig). A system of equations based on the URANS model and the k-ε model of turbulence was used. The gmsh utility was used to build the computational grid. The temperature, velocity fields for gas and solid particles, concentrations fields of gas in particles and ash in particles have been calculated for given flow rate of coal particles in the valid test rig. The calculations were run on a computing cluster of the web-laboratory of UNICFD ISP RAS. Each calculation was performed on 48-64 cpu cores.
Flow around the wing models with straight and swept leading edge in case of contact with turbulent wake
Authors: Pavlenko A M , Zanin B Yu , Bykov A V , Katasonov M M
Published: December 2019

The paper presents the results of experimental studies of the flow around wing models with a straight and swept leading edge in contact with a turbulent wake. The experiments were carried out in subsonic wind tunnels at low Reynolds numbers. A fluffy thread was used to simulate a turbulent wake in the flow. The flow patterns on the surface of the wings were obtained before and after the impact of the turbulent wake at various angles of attack, wing sweep angles and free-stream velocity values. It was found that the wake has a significant effect on flow separation and on vortex structures arising above the wings. The evolution of the vortex flow patterns in the areas of separation of the boundary layer and with a change in the flow regime is shown.
Multi-spectral planar imaging using a tuneable Lyot-Ehman filter
Authors: Sharaborin D K , Dulin V M
Published: December 2019

The paper provides results of the assessment of a multi-spectral 2D imaging by using a tuneable band-pass optical filter. The filter is based on the Lyot-Ehman physical principles and uses liquid crystal cells as polarization rotators. The spectral properties of the filter are tested by imaging fluorescence of a Rhodamine dye solution. Full width at half maximum of the band of the filter was found to be 9-10 nm in the tested range of 520-620 nm. The filter is applied for 2D imaging of local spontaneous Raman scattering in a laminar premixed Bunsen flame. It is shown that the local intensity of Stokes and anti-Stokes components of rovibrational transitions during the light scattering by nitrogen molecules can be captured by using this filter. It is also concluded that the filter can be used for 2D imaging of local fluorescence in gases or liquids.
Investigation of unsteady flow regime in a T-shaped channel by means of Time-Resolved PLIF and PIV techniques
Authors: Shestakov M V
Published: December 2019

T-shaped channels are widely used as micro-mixers in microfluidic systems for chemical and biochemical engineering applications. The mixing efficiency of T-shaped channels relies on three-dimensional flow structure which is dependent on Reynolds number. The most favourable flow regime with relation to the mixing efficiency is an unsteady engulfment flow regime, which has a periodic nature. In the present work, the spatial and temporal scales formed in a T-shaped channel are studied at Reynolds number corresponding to unsteady three-dimensional flow regime. The combination of PLIF and PIV techniques with the high temporal resolution was used in the T-channel cross-sections to investigate the evolution of velocity and concentration fields.
Applying phase averaging technique to analysis of unsteady twin vortex structure observed in tangential vortex chamber
Authors: Skripkin S G , Dremov S V , Shtork S I
Published: December 2019

This paper is devoted to experimental investigation of formation of precessing vortices pair in a vortex chamber with a cylindrical working area. Flow structure was registered by means of a high-speed visualization technique. Quantitative measurements characterizing the vortex properties were carried out using a 2D particle image velocimetry (PIV) technique synchronized with wall pressure measurements. The results show that two symmetrical precessing helical vortices are present downstream of the tangential nozzles.The phase- averaged analysis confirms the presence of large-scale twin vortex structure that visualized by small air bubbles dissolved in water.
Flow structure and heat transfer around the cube
Authors: Terekhov V V , Bogatko T V , Korobkov S V
Published: December 2019

In this paper we present the results of a numerical study of convective heat transfer from a single cube, located on a plane surface perpendicular to the incoming flow. The Reynolds numbers, calculated from the height of the cube and the average velocity, are Re = 4200 and 46400. Numerical simulation is performed using the RANS and LES methods. The working fluid is air. Thermal condition on a flat surface and on the cube faces is a constant heat flux. A three-dimensional picture of the structure of the horseshoe-shaped vortex around the cube is clearly shown. Areas with maximum pressure loads on the surface of the cube are identified. The main attention is paid to the peculiarities of heat transfer in the flow around a cube with a turbulent flow. Areas on the cube surface where the most effective heat transfer occurs, as well as low-efficiency stagnant zones with low fluid velocity and high temperatures are shown. The obtained data on aerodynamics and heat transfer are compared with the experimental data of other authors.
The structure of separated flow and heat transfer in a round tube with single detached diaphragm
Authors: Terekhov V I , Bogatko T V
Published: December 2019

Here we present the results of numerical investigation of the flow structure and turbulent heat transfer obtained in a round tube with a diaphragm of height h and some gap c between the tube and the diaphragm. The value of gap between the diaphragm and tube wall was changed within A = c/h = 0 ÷ 0.33. It was defined that an increased distance between the diaphragm and the tube wall modifies the structure of recirculation zone and eliminates the stagnation areas in the region of secondary vortices. The flow regime, when the values of average heat transfer behind the diaphragm with a gap are higher than the same values for the attached rib, was determined. When increasing the gap height from 0 to 0.33, the 30-% increment in the coefficient of thermal enhancement was achieved.
The development of instability of Richtmyer–Meshkov in the interaction of a shock wave with a two-component medium consisting of light and heavy gas
Authors: Zyryanov K I , Ruev G A
Published: December 2019

On the basis of the previously formulated mathematical model of the mechanics of a two-speed two-temperature mixture of light and heavy gases, the evolution of a system of two cylinders of heavy gas after the passage of a shock wave through it is numerically investigated. The analysis of the obtained data on the dependence of the spatial expansion on time, as well as the kinematic characteristics of the system showed their satisfactory compliance with the experimental data for all initial separations of the cylinders. The influence of the initial separation of cylinders on the flow morphology is investigated.
Influence of detailed mechanisms of chemical kinetics on propagation and stability of detonation wave in H2/O2 mixture
Authors: Borisov S P , Kudryavtsev A N , Shershnev A A
Published: December 2019

In the present paper, detonation in a stoichiometric oxygen-hydrogen mixture is simulated numerically using 4 detailed chemical mechanisms. The effect of chemical kinetics models on the stability of 1D detonation wave and 2D detonation wave propagating in a plane channel is investigated. The number of detonation cells formed in a channel of a given width at different degrees of overdrive is determined. Simulations are performed using a previously developed computational program based on high-order shock-capturing TVD schemes and a finite-rate chemistry solver. The program is implemented in C++ using the CUDA parallel computing platform for running on graphic processor devices (GPU), the open OpenMP standard for multi-threaded applications on multiprocessor systems with shared memory and the MPI protocol for data exchange between processors.
Numerical simulation of synthesis gas/air and methane/air flames for model combustion chamber with swirling flow
Authors: Lobasov A S , Dekterev Ar A , Minakov A V
Published: December 2019

This paper reports on the investigation of combustion features of synthesis gas/air and methane/air flames in a model gas turbine combustor with swirling flow via numerical simulation. This combustor developed for experimental investigation of flow, heat transfer and combustion. For synthesis gas combustion ratio of hydrogen and carbon monoxide was 1:1. The equivalence ratio Φ in both cases was 1.5. The combustor contains systems for water- and air-cooling that provides reasonable temperature value of combustor walls in operating mode. The methane/air flame has the lifted V-shape and synthesis gas/air flame has the columnar tubular flame. In practical, the V-shape flames are more often used. To provide more practical combustion regimes for synthesis gas/air mixture it is necessary to increase the fuel-oxidant mixing efficiency in the premixer of the combustor.
Computation of equilibrium states for products of hydrocarbon combustion under oxygen lack
Authors: Prokhorov E S
Published: December 2019

A unified approach to the computation of equilibrium in combustion products of oxygen mixtures overriched with hydrocarbon fuel, when both gaseous and condensed carbon phases may appear simultaneously among the components of chemical reaction, has been formulated. Within the framework of this approach, the problem of determining the equilibrium parameters (pressure, density, temperature, etc) of chemical reaction products produced at explosion of acetylene-oxygen mixture in a closed volume as the values of molar fraction of fuel (acetylene) vary up to the values when oxygen in the mixture is almost absent has been solved.
Turbulent charge burning in SI engines
Authors: Briutov A A , Senachin A P , Senachin P K
Published: December 2019

The article describes turbulent combustion in the front of a spherical flame of the fuel-air mixture in a spark-ignition engine. The paper considers two mathematical models of the workflow : a well-known “entrainment or eddy burning model” and a “laminar model of turbulent combustion” in the authors’ version of this paper. Both models are based on the Damköhler hypothesis (Damköhler G., 1940) on the turbulent combustion of gas, but have a significant difference in the mathematical formulation. Although both models contain empirical parameters, the authors’ model is much simpler and clearer. In numerical simulation, both mathematical models produce similar results. The authors also propose a “combined mathematical model of frontal turbulent combustion”.
Numerical study of flow condensation of dielectric liquid in microchannel
Authors: Safonov S A , Kuznetsov V V
Published: December 2019

This paper presents a numerical analysis of flow condensation of dielectric liquid perfluorhexane in a rectangular microchannel using the annular flow model. It is shown that accumulation of liquid near the channel corners causes the heat transfer enhancement due to liquid film thinning. The numerical method is validated against experiments and predicts well the average heat transfer coefficients during flow condensation in a rectangular microchannel for vapor quality higher than 0.5.
Modeling the filtration of liquid with ultra disperse solid particles in porous media
Authors: Kuznetsov V V
Published: December 2019

This paper considers an approach for modeling the filtration of a viscous liquid, containing ultra disperse solid particles, through the porous sample. The mechanism of microparticle retention during filtration of the suspension at supported pressure drop is discussed and the dependence of reduction of average permeability on particles size is documented.
Dynamics of gas slugs in a vertical annular channel
Authors: Kashinsky O N , Kurdyumov A S
Published: December 2019

Experimental studies of gas slug motion in an annular channel were performed. The channel consisted of two concentric pipes with the diameters of 32 and 10 mm. Experiments were performed for different values of liquid velocity. Slug velocity was measured using optical sensors. Wall shear stress measurements were performed using an electrodiffusional technique. It was shown that the shape of the slug in the annular channel differs significantly from that in a pipe. The distribution of wall shear stress along the slug was presented for different positions of the slug.
Mathematical modelling of influence of the variable incidence at the supersonic flow around spherically blunted cone on the characteristics of the conjugate heat and mass transfer
Authors: Efimov K N , Ovchinnikov V A , Yakimov A S
Published: December 2019

Results of a numerical study of the three dimensional supersonic flow over a spherically blunt cone fluctuating in a pitch plane taking into account mass breaking down blowing and heat transfer between body and flow are presented. Influence of the body fluctuation with angular velocity in range of 0–100 deg/s on surface temperature distribution and heat transfer characteristics is considered. The effect of the body fluctuation on characteristics of conjugated heat and mass exchange in a thermal protection material is analyzed.