bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of criteria and sub-criteria for selection of spare parts raw material supplier using the Delphi method
Authors: Ishak Aulia , Wijaya Tommy
Published: June 2020

Spare parts are goods that consist of several components that form a single unit and have certain functions. The development of the number of motorized vehicles in Indonesia from 2012-2017 has always increased, with a growth rate of 31.88%. The selection of the right supplier is not only profitable for the company but also can increase customer satisfaction. Therefore in the selection of suppliers the company must have a system of selection and evaluation of suppliers of raw materials and components. This research was carried out on car spare parts production companies with raw materials in the form of rubber. This study aims to obtain criteria and subcriteria in selecting suppliers of spare parts raw materials by using Delphi Method. The results of the Delphi Method obtained 9 supplier selection criteria, namely: Quality, Delivery, Guarantee and Complaint Service, Price, Manufacturing Capability, Quality Management System, Documentation and Self Audit, Development Design Capability, and Cost Reduction. Based on the 9 criteria obtained 55 sub-criteria that can be used by companies in selecting suppliers of spare parts raw materials.
Reliability investigation of steam turbine critical components
Authors: Sabri M , Immanuel Sibarani Adven , Sabri Faris A M , Geubrina H S
Published: June 2020

Several aspects of maintaining and operating steam turbines at the palm oil mill areas have historically resulted in unreliable performance and repetitive failures. The reliability analysis using Weibull probability distribution for various components of steam turbine is discussed extensively. The objective of this reliability assessment is to identify the potential failure path of steam turbine components. The intent herein is to focus on critical components of steam turbine to successfully improve the integrity and reliability of turbines in those components. Areas discussed will be bearing failures, Shaft Seal failures, Control/stop Valve, Main Oil Pump, and Reducing Gear. It is necessary to improve the reliability indices of the steam turbine components by taking some measures such as well-planned and routine maintenance of equipment’s as well as training and retraining of technical human resources of the major equipment like steam turbine.
The comparative analysis of solar desalination with cooling glass
Authors: Ambarita H , Nababan J P , William
Published: June 2020

Fresh water plays a role and is responsible for life. The need for fresh water continues to increase due to its use in various fields of life, such as agriculture, industry and population. To prevent water shortages, it is very important to show the gap between the demand and supply of drinking water by developing water purification technology. Solar power / solar energy (renewable energy sources) in the form of distillation is one of the most promising, simple, and economical technologies for the purification of salt and brackish water. double slope passive system with the addition of water-cooled glass outside with water diluted by a solar-powered DC pump from photovoltaics with no outer glass cooler.
Automated pneumatic vacuum suction robotic arm with computer vision
Authors: Lim J , Yang P , Yuanda P , Bakkara R V , Sinaga M , Siagian H , Suryanto E D , Perangin-angin D
Published: June 2020

In this paper, a 4 DOF robotic arm that made of acrylic was built and equipped with a 5 MP USB camera, a pneumatic vacuum suction cup and a small air pump. An image will be captured by the camera and then processed with computer vision algorithms. The algorithm will extract the coordinate from the object image. The extracted coordinate data from test objects then fed to the microcontroller. Pulses were generated by the microcontroller to the driver module to control the motors. Some parameters were changed and adjusted accordingly to achieve a different result for analysis purpose. Objects that are used in this research are boxes with various shapes, colors, surface sizes, and weight. The result, the robot was able to reach the object within 2 mm to 4 mm tolerance. Image processing algorithm centroid calculation errors are within 2 mm. Vacuum pickup success rate is 99%.
Engineering education system between Indonesian Vocational School and Japanese KOSEN
Authors: Siswanto A P , Budiyono  , Kasai H , Fujiwara S , Mizuno Y
Published: June 2020

International partnership has become an emerging issue in which due to globalization goals, the needs of having collaboration between countries are inevitable. Cross-continents collaborations are encouraged; however, having partners with similar cultural background is seen more beneficial. This article aims to review challenges on programme development of Vocational Education between Indonesian and Japan. Vocational Education in Indonesia has been well established for decades where students are trained in 3-year education of Vocational High School then continue to 3-year education of Vocational School at the University. Curriculum is set to be more giving practical training which can enhance skills of students in problem solving. Moreover, KOSEN is one of distinctive education systems in Japan which is an abbreviation of Japanese form “koku-ritsu-kou-gyou-KOU-tou-SEN-mon-gak-kou” which is translated as National Institute of Technology. It offers 5-year education after Junior High School which provides training and skills development for students. Programme development of KOSEN and Indonesian Vocational Education are seen to be feasible for being implemented further which can deliver more skilful graduates. Combination of skills and cultural side of graduates are expected to be positively influencing their working ethics. Comprehensive capability of graduates is linear to their competency which also increases their employability.
Implementation of bandwitdh management using microtic router
Authors: Widia I D M
Published: June 2020

Computer network is a group of computers that are interconnected between one another and use communication protocols through communication media so that can share and exchange information. In a network technology required a device that can perform management between existing networks. These devices are called routers. The use of internet connection together on Local Area Network requires the existence of gateway and router. Microtic OS is a reliable operating system to operate as a gateway and router. Bandwidth management is required to share the bandwidth capacity available in the network appropriately for each client and application. The clients are expected to get the optimal bandwidth capacity as needed. This makes it easier for network administrators to monitor internet access in each part, because the bandwidth management has been done.
Numerical Investigation on Critical Velocity of Ice Slurry Flow
Authors: Rawat K.S. , Verma A. , Pratihar A.K. , Singh A.K. , Maheshwari P.
Published: June 2020

The use of ice slurry as a working fluid in secondary-loop of refrigeration system not only enhances the system performance but also reduces the refrigerant charge and its leakage to environment. It can be transported through pipes; however, flow of ice slurry is a quite complex two phase flow, which significantly differs from conventional fluid flow. Ice slurry flow can be influenced by on several operating parameter viz. initial velocity, ice concentration, freezing point depressant concentration and particle size. Solution of such type of flow through pipe is a difficult task through experiments due to complexities in visualization and measurements. Therefore, a CFD model is developed to simulate the ice slurry flow to predict the safe conditions for the transportation of ice slurry. In the present work, numerical investigation of flow of ice slurry has been analyzed in order to predict the critical velocity and effect of different parameters on critical velocity. Eulerian granular flow model has been used for the simulation, which is also validated with existing experimental results in the literature. Result shows that, the critical velocity is especially influenced by the particle size. Critical velocity at 10 % initial ice concentration increases from 0.4 m/s to 0.16 m/s with increase in particle size from 0.1 mm to 0.4 mm.
Comparative Study for Thermal and Fluid Flow Peculiarities in Cascading Spiral Inner Tube Heat Exchanger with or without Diverse Inserts over Spiral Tube
Authors: Kaushik Shivasheesh , Singh Satyendra , Kanojia Nikhil , Rawat Kuldeep , Panwar Kuldeep
Published: June 2020

Present work deals with experimental analysis in which various observation takes place related to performance characteristics like HTR, effectiveness and fluid flow peculiarities like Nu, Re, f, NTU, TPF etc in a cascaded spiral concentric tube type heat exchanger consisting of a GI shell and a cascaded spiral copper inner tube having conical shape inserts, hemispherical insert and plane profile unit for parallel flow. Five spiral cascades with three turns in each are used for the inner side copper tube unit. Water enters at 304°K from the innermost turn along the cascaded spiral tube, and leaves at the outermost turn. The hot fluid inlet for heat exchanger is from bottom of one end of the shell at 333°K, flowing radically across the cascades, and then leaving the exchanger from the top of another end. This paper based on comparative experimental study of the behavior of such system for parallel flow with different shape of inserts, and then compared with the simulation results for same. In this analysis comparative approach is considered for evaluating optimum fluid flow and thermal properties on the basis of geometrical parameters. The results predicted that out of three profiles of insert, plain, conical and half cut elliptical profile, which located over inner copper tube of exchanger, half cut elliptical profile insert shows best results on fluid flow and thermal peculiarities, for mass flow rate range 0.012 to 0.049 Kg/s and Reynolds number range 4236 to 18540, heat transfer rate varies from 1128.06 to 2374.77, Nusselt number varies from 75.15 to 144.05, Friction factor varies from 0.00376 to 0.00305 and effectiveness varies from 0.77 to 0.40 and Number of transfer unit varies from 2.08 to 0.68 for half cut elliptical profile.
Influence of Friction Stir Welding Parameters on Mechanical Properties of dissimilar AA 7475 to AISI 304
Authors: Goel Pankul , Saxena Ankit Kumar , Wahid Mohd Atif , Rathore Sachin , Sharma Nidhi , Kant Mishra Radha
Published: June 2020

Joining of dissimilar materials is difficult and challenging. Trend towards replacement of high density material (HDM) by low density material (LDM) is gaining importance in automotive industries. In the present work, friction stir welding (FSW) of high strength dissimilar materials i.e. aluminium alloy AA7475-T761 and stainless steel AISI 304 was conducted. The mechanical properties and microstructure of butt joint were investigated on using Taguchi L8 orthogonal array (OA). Different combinations of FSW parameters were used to obtain the maximum value of UTS. It was observed that most dominating parameter affecting UTS is tool rotational speed, contributing 42.19%, followed by traverse speed with 38.96% and shoulder diameter with 12.60%. The maximum UTS was observed 75.22% of base material AA 7475 (452MPa) under the optimum combination of parameters; tool rotational speed at 450 rpm, traverse speed 63 mm/min and shoulder diameter 14 mm. The microstructure of the resulted efficient joint shows appreciable variation in grain sizes in different zones and the micro hardness was found maximum in SZ on the retreating side.
Green Synthesis, characterization of Zinc oxide nanoparticles using Chromolaena odorata extract and evaluation of its properties for photoanode of solar cells
Authors: Balogun SW , Sanusi YK , Agboluaje BA
Published: June 2020

Synthesis of Zinc oxide nanoparticles (ZnONPs) using plant extract was carried out in this work because of its advantages over other method of synthesis namely; simplicity, environmental friendliness and elimination of toxic chemicals. Fresh Siam leaf extract was characterized over a period of 10 days to study the effect of time on the optical photon energy absorption properties. ZnONPs was synthesized and deposited on substrate by spin-coating method and characterized by UV-vis spectroscopy, Fourier transform infra-red spectroscopy, Scanning Electron microscopy, and Energy Dispersive X-ray. ZnONPs thin film device was then fabricated to study the electrical properties. From UV-vis spectroscopic result, as the time (day) increased, there was an increase in the value of the transmittance and corresponding reduction in photon energy absorption. FTIR result gives the functional groups and absorption number at 3448.04cm−1 O-H single bond, 2524.85cm−1 C-H bond, 1437.15 cm−1, 880.59 cm−1, 729.06 cm−1, 433.44 cm−1 Zn-OH and Zn-O variety of single bond. The surface morphology shows large grain size. Energy band gap of ZnONPs was approximately 3.7 eV. The fabricated ZnONPs thin film device under illumination has efficiency of 2.010/0. From the morphology, optical, and electrical properties of the ZnONPs thin film and device, it could be a suitable material for crystalline solar cells as photoanode.
Improved power conversion efficiency in Perovskite solar cell using silver nanoparticles modified photoanode
Authors: Eli D , Onimisi MY , Garba S , Gyuk PM , Jamila T , Boduku HP
Published: June 2020

Metal nanoparticles have demonstrated outstanding properties in photovoltaic devices through introducing localized surface plasmon effects. The performance of Perovskite solar cell (PSC) by incorporating Ag@P4VP NPs was investigated systematically. The plasmonic enhancement effects are explored based on the combination of UV-visible absorption spectroscopy and Scanning Electron Microscope (SEM). The performance, especially the short circuit current density(Jsc), and open circuit voltage(Voc)of the PSC containing Ag@P4VP NPs was significantly affected. The power conversion efficiency(PCE), JscandVocofthe reference device shows a value of 3.80 %, 11.04 mAcm−2and 0.85 V. Upon introducing AgNPs@P4VP, aPCEof 5.69 %,Jscof 12.61 mAcm−2andVocof 0.88 V were recorded, which improved thePCE∼ 39.4 % over that of the standard device. The improvement is attributed to an increase in photocurrent density due to enhanced light harvesting by silver nanoparticles.
Assessment of micro-morphology of the leaves of Solanum nigrum (L.), Amaranthus hybridus (L.) and Celosia argentea (L.) cultivated using kola pod extract-mediated AgNPs as biofertilizer
Authors: Ogundola A F , Liasu M O , Ogunkunle ATJ , Ajao OS , Jimoh MO
Published: June 2020

In this study, assessment was made on the growth response and micro-morphology of the leaves of Amaranthus hybridus, Celosia argentea and Solanum nigrum cultivated using super grow (Golden Neo-Life Diamite-(GNLD) bio-fertilizer, kola pod extract-mediated AgNPs with super grow. AgNPs was synthesized biologically making use of pod extract of Cola nitida. A pot experiment was conducted to cultivate the three vegetables on soil from botanical gardens, LAUTECH in 5 kg soil capacity pots and super grow (biofertilizer) and mixture of AgNPs and super grow were applied at the second week after planting. Data were collected from the plant growth parameters. Random ccollection of the leaves was done at the onset of flowering and prepared for viewing with a binocular light microscope (Olympus) at 100X and 400X magnifications. Photographs were obtained digitally with Android phone using Microsoft image programme for windows. Statistical analysis of variance was done used MINITAB release 17, and means were separated with Fisher’s Least significant different at p<0.05. Leaves of plant treated with AgNPs have their micro organs (stomata and subsidiary/epidermal cells) bigger in sizes and increased in densities. This situation was observed in the leaves of the three plant species used in this study. Conclusively, Kola pod extract-mediated AgNPs strengthened the super grow and influenced the growth response as there was significant difference among the values recorded from the treatments. Also, micro-morphology of the AgNPs treated plant samples recorded significant values.
Effect of particle size of rice husk ash on aluminium/graphene composites
Authors: Yekinni AA , Durowoju MO , Agunsoye JO , Mudashiru LO
Published: June 2020

Aluminium/graphene (Al/G) composite has gained wider engineering applications because of its unique properties such as lightweight, excellent corrosion resistant, improved strength and enhanced thermal conductivity. However, difficulty in dispersing graphene in molten aluminium remains one of the major optimization challenges. This study developed, by stir casting technique, composites of aluminium alloy from recycled aluminium can, 0.4 wt. % graphene (G) and 1.6 wt.% rice husk ash (RHA) with particle sizes of 150, 300 and 600 μm. The tensile, hardness, impact and fatigue properties were analyzed using Instron Extensometer, Vickers hardness tester, Charpy Impact machine and rotating fatigue machine respectively. Furthermore, the cast samples were characterized using scanning electron microscope (SEM) and X-ray diffractometer (XRD). The morphology of the microstructure of all composites showed the retention and uniform distribution of G and RHA particles in the Al matrix devoid of presence of harmful aluminium carbide with improved mechanical properties. The study established a new approach of dispersing graphene in molten aluminium through a stir cast method with 150 μm particle size of RHA given the best mechanical and morphological properties.
Enhancing the thermal performance of solar collectors using nanofluids
Authors: Omisanya M I , Hamzat AK , Adedayo SA , Adediran IA , Asafa TB
Published: June 2020

Solar energy remains the most ubiquitous and inexhaustible source of energy. This energy can be utilized by several approaches including the use of solar collectors. Several studies have illustrated that the efficiency of solar collectors can be significantly improved by the introduction of nanofluids which have shown improved thermal conductivity up to 160% with a subsequent reduction in greenhouse gases such as CO2. To produce nanofluids, nanoparticles such as Al2O3, hybrid ZnO + Al2O3, and metals (Al, Cu) particles are dispersed into the based fluids such as water, glycerol, and bio-fluids. The added nanoparticles enhance the viscosity, absorption rate, convective heat transfer coefficient and heat losses of the fluid. The performance of details the applications and effectiveness of different nanofluids in four types of solar collectors - parabolic trough, flat plate, direct absorption, and evacuated tube. In addition, the work sheds light on the future trend and challenges of nanofluids (including toxicity) in solar collectors. Regardless of its toxicity, researchers have shown more interest in nanofluids use in solar collectors because of its strong sustainability to a safe environment and the exploration of hybrid nanofluids to better enhance solar collectors. Solar collectors can also be modulated by using different nanofluids at varying concentrations.
Influence of XL-bond nanochemical on strength indices of weak lateritic soil
Authors: Olaniyan OS , Ajileye VO , Adewusi MO , Aransiola DO , Ayanlola JA
Published: June 2020

Lateritic soil is among the major construction materials in road pavement. However, obtaining lateritic soil with sufficient strength is difficult and stabilization with cement is expensive. Stabilization with cement and lime has been well reported but there is paucity of information on stabilization with XL-Bond nanochemicals. In this study, the strength characteristics of stabilized lateritic soil with XL-Bond nanochemical were investigated. Lateritic soil samples were taken from Bariga and Mushin, Lagos State, Nigeria borrowpits (A: Latitude 6.5391°, longitude 3.3849°) and (B: Latitude 6.5273°, longitude 3.3414°), respectively. The geotechnical properties which include Moisture Content (MC), Particle Size Analysis (percentage passing sieve no 200), Plastic Index (PI), Optimum Moisture Content (OMC), Maximum Dry Density (MDD), Unconfined Compressive Strength (UCS) and California Bearing Ratio [CBR] (soaked) of lateritic soils were determined at natural state. The lateritic soils were stabilized at 2, 4, 6, and 8% of XL-Bond nanochemical by dry unit weight of the soil samples. The PI, MDD, CBR (soaked and unsoaked) and UCS of stabilized laterite soil samples were determined in line with standard methods.

The MC, percentage passing sieve no 200, PI, OMC, MDD, UCS and CBR (soaked and unsoaked) of soil samples A, B were (45.6%, 38.98%, 5.0%, 10.5%, 2420 g/m3, 59kPa, 12.0% and 10.0% ); (41.1%, 54.52%, 2.0%, 12.50%, 1960g/m3, 72kPa, 4.0% and 20.0%), respectively. The PI, MDD, CBR (soaked and unsoaked) and UCS of stabilized soil with XL-Bond varied from (3-7%; 2.30-2.35g/cm3, 12-23%, 23-50% and 64-83 kPa) and (3-6%; 1.44-1.50g/cm3,6-20%, 21-40% and 79-8 kPa), respectively. There is significant effect of varying percentage of XL-Bond on CBR of stabilized samples (P = 0.1004>0.05). In conclusion, stabilization of Laterite soil with XL-Bond nanochemical enhanced its compressive strength. The stabilized lateritic soil can be used as subgrade materials in highway construction.
Inhibition efficiency of silver nanoparticles solution on corrosion of mild steel, stainless steel and aluminum in 1.0 M HCl medium
Authors: Asafa TB , Odusote JK , Ibrahim OS , Lateef A , Durowoju MO , Azeez MA , Yekeen TA , Oladipo IC , Adebayo EA , Badmus JA , Sanusi YK , Adedokun O
Published: June 2020

Research work on corrosion behaviour of metals and their alloys continues to attract considerable attention because of the huge cost required to prevent corrosion and replace failed or contaminated components due to corrosion reactions. Different inhibitors have been used to minimize corrosion rate, but addition of nanoparticles has been reported to enhance inhibition efficiency. In this work, the influence of silver nanoparticles (AgNPs) on inhibition of corrosion of mild steel, stainless steel and aluminum in 1.0 M HCl were investigated. Biosynthesized AgNPs were acquired from Laboratory of Industrial Nanobiotechnology, Ladoke Akintola University of Technology Ogbomoso. The particles were hitherto characterized using FTIR, UV-Vis and TEM. Five concentrations of AgNPs solution (0, 5, 10, 15, and 20 μg/ml) were added to 1.0 M HCl. The corrosion inhibition effects of the AgNPs on the metal samples were analyzed using gravimetric (weight loss), potentiodynamic polarization and gasometric (hydrogen gasevolution) approaches. Gravimetric study was conducted within 2000 h of exposure, and the results showed that weight loss increased with exposure time but decreased with increased concentration of AgNPs solution. In addition, inhibition efficiency was enhanced by the addition of AgNPs solution; 52% for mild steel, 70% for stainless steel and 62% for aluminum. Gasometric results revealed that the volume of hydrogen gas evolution reduced with increased exposure time and concentration of AgNPs solution. Furthermore, potentiodynamic polarization results showed that the presence of AgNPs modified the mechanism of anodic dissolution and cathodic hydrogen gas evolution. These results indicated that AgNPs can be incorporated into the existing inhibitors towards minimizing corrosion rate.
Green synthesis of silver nanoparticles (AgNPs) for optical and photocatalytic applications: a review
Authors: Kareem M A , Bello I T , Shittu H A , Awodele M K , Adedokun O , Sanusi Y K
Published: June 2020

Nano-sized particles of silver (Ag) whose diameter falls within 1-100 nm range possess an exceptional physico-chemical, biological and antimicrobial properties. As a result of their unique properties, silver nanoparticles (AgNPs) have been vigorously investigated. In the last decade, several trials have been made to heighten the green methods of formulating AgNPs to reduce the danger of the by-products from chemical methods. A clear understanding of AgNPs properties is absolutely necessary in order to make the best use of these nanoparticles in various fields, while their effect on man and environment is reduced to the least achievable. This review aims to discuss the green methods of preparing AgNPs and its numerous applications in the area of opto-electronics and environmental remediation. Many natural biomolecules in plants and microorganism were involved in formation, stabilization and bio-reduction of AgNPs. Over the years, several discoveries have reiterated that the catalytic and optical properties of AgNPs are dependent on the size, size-distribution and shape, which show variation by differing their synthetic approaches, stabilizers and reducing agents. In this review, silver nanoparticles have been reported to produce a desired result as a promising photocatalytic material and with a viable application in opto-electronic device. Thus silver nanoparticles are considered useful for having diverse range of applications for the benefits of man.
Effect of low temperature synthesis of carbon nanotube nanocomposite on the photovoltaic performance of anode buffer layer in polymer solar cells
Authors: Oyeshola H O , Adisa M A , Adejumo B K , Babalola K K , Agboluaje B A , Adedokun O , Sanusi Y K
Published: June 2020

Today’s solar cells are simply not efficient enough and are currently too expensive to manufacture for large-scale electricity generation. However, potential advancements in nanotechnology may open the door to the production of cheaper and slightly more efficient solar cells. This research is based on the study of photovoltaic properties of low temperature synthesized carbon nanotube (CNT) nanocomposite as an anode buffer layer for the PEDOT:PSS based polymer solar cells. CNT was synthesized using simple and cost effective method at low temperature. The structural and optical properties of prepared CNT samples were characterized using X-ray diffraction (XRD) analysis, Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM) and UV spectroscopy. CNT/PEDOT:PSS nanocomposite solutions was prepared and spin coated on a cleaned glass substrate at different spin coating speed, the fabricated buffer layer thin film devices were annealed from 100 °C to 500 °C, their optical and electrical properties were then analyzed. The XRD of synthesized CNTs nanoparticles show diffraction pattern which exhibit tetragonal structure and FTIR shows functional group of carbon nanotube. The SEM image showed that the obtained sample maintained tubular structure, cluster at 20 nm but properly dispersed at 100 nm. The optical studies of the films show an increase in absorbance as the annealing temperature increases. The photovoltaic performance of the polymer solar cell showed an improved efficiency of 6.44 % for optimized device. It is deduced from this work that low temperature synthesized CNT nanocomposite demonstrated better performance as anode buffer layer for high efficient polymer solar cells.
Nanobiosensors: applications in biomedical technology
Authors: Banigo AT , Azeez TO , Ejeta KO , Lateef A , Ajuogu E
Published: June 2020

Biosensor devices are composed of bioreceptor, transducer and detector that detect and aid in measuring parameters of some primary metabolites, immunological molecules and many more materials. These devices are of various types including piezoelectric which exhibit high efficiency based on sensitivity, response time, selectivity and linearity. Currently, newly developed nanobiosensors help in transduction and are employed to sense biomolecules bearing high sensitivity. Nanobiosensors also could be homogeneous or heterogeneous in nature and equally function in sensing mechanism of the biosensing technology. Thus, different nanobiosensors are greatly utilized to reduce poison in products, disease diagnostics and in many biomedical applications. Based on all these factors and the positive impact of using these devices; nanobiosensor types, applications, challenges and preferred solution in biomedical technology were considered and discussed in this work.
Biosynthesis and bactericidal activity of silver nanoparticles (AgNPs) using cell-free bioflocculant from domestic wastewater bacterial consortium
Authors: Adebayo E A , Kumi E O , Ajibade V O , Akinjo A O , Abiola O S , Raji M A , Adepoju Y , Oduoye O T
Published: June 2020

Water bodies are becoming contaminated by chemicals and harmful microorganisms like bacteria, which often cause serious illnesses and at times death. It is therefore pertinent to find a mean of purifying wastewaters and larger polluted water bodies. This research aimed at isolating bioflocculant–producing bacteria to synthesis silver nanoparticles (AgNPs) for water purification and antimicrobial activities. Wastewater was collected from eateries (sites A and B) around LAUTECH Ogbomoso; the bioflocculant–producing bacteria were isolated and characterized to species level using molecular tools and registered in the GenBank database. Kaolin (5 g/L) suspension was used to measure the flocculating activity of isolated organisms at an optical density (OD) of 550 nm. The cell-free bioflocculant was used to synthesize AgNPs and its potentials to reduce the microbial load of polluted water were evaluated. The isolated strains were characterized and identified as (A)Bacillus polymyxa(KY705398),Bacillusspecies (KY705399),Bacillus alvei(KY705400) andBacillus subtilis(KY705401); (B)Klebsiella pneumoniae(KY706100),Providencia stuartii(KY706101), andAcinetobacterspecies (KY706102). The consortium organisms gave flocculating activity of 92.46% (A) and 60% (B). The UV-vis spectroscopy showed AgNPs with surface plasmon resonance at 570 nm and 460 nm for sites A and B respectively. FTIR peaks of AgNPs (A) (3525, 3284, and 1179 cm−1) and (B) (3611, 3307 and 2492 Cm−1), pointed to protein as both capping and stabilizing agents for the synthesized nanoparticles. Synthesized AgNPs exerted total reduction of microbial load in faecal polluted wastewater of 146 CFU/ml at a 10−5factor at a concentration of 20 μg. The results obtained revealed that cell-free bioflocculant AgNPs has bactericidal activity and it could be used as efficient water purifying agent.
Synthesis and characterization of silver nanoparticles-doped titanium (IV) oxide thin films
Authors: Balogun SW , Abdulhamid AB , Sanusi YK , Adedokun O
Published: June 2020

Current advancements in nanotechnology appear to open a more efficient, stable, and cheaper way of producing solar cells to replace the too expensive means of inorganic solar cells production. The creation of nanoscale materials for advanced structures has led to a growing research interest in the area of photovoltaic energy conversion using photovoltaic devices. This research investigates the impact of annealing temperature on the optical properties of silver nanoparticles-doped titanium (IV) oxide thin film (TiO2:AgNPs) deposited by spin-coating method on glass substrate. AgNPs were prepared using the leaf extract of Gliricidia sepium as a reducing agent for silver nitrate. Deposition of TiO2:AgNPs composite solution was performed in different volume ratio. Deposition of TiO2:AgNPs volume ratio (1: 0.2) was performed with different spin-coating speed for 30 seconds at 7 different thicknesses. Characterization of the optical properties of thin films was carried out by using a UV-vis single beam spectrophotometer; this was used to calculate the absorbance and the bandgap energy. Sixteen 16 samples of TiO2:AgNPs deposited at 1000 rpm on the glass substrate were annealed at temperature range of 50 to 425 °C with step of 10 °C interval in a tubular furnace. It was observed from the results that the peak absorption of photon energy occurred at 375 °C in the visible spectrum of the wavelength band. The optimal thickness for peak absorbance of the TiO2:AgNPs blend layer occurred at 115 nm in the visible spectrum and at the corresponding spin speed of 1000 rpm. The optimized fabrication process with blend layer thickness of 115 nm yielded the best absorbance at an annealed temperature of 375 °C in the visible spectrum. The volume ratio of (1:0.2) gave the peak absorption at 0.75 au. At 1000 rpm with the corresponding thickness of 115 nm, TiO2:AgNPs blend has the peak absorbance. The energy band gap of the blend thin film is 3.58 eV at 375 °C in the visible spectrum of wavelength band. The result obtained showed that AgNPs enhanced light absorption, broadened absorption spectral range and thermal stability of titanium (IV) oxide film. The result can be used as a guideline in the design and fabrication of solar cells.
Effects of pH, temperature and agitation on the biosynthesis of iron nanoparticles produced by Trichoderma species
Authors: Kareem SO , Adeleye TM , Ojo RO
Published: June 2020

There is an increasing global search for commercially and environmentally clean synthesis of metallic nanoparticles from bioresources. However, there is insufficient reported information on the production of iron nanoparticles (FeNPs) from fungi such as Trichoderma species which has potentials for greater for yield of FeNPs as compared with bacterial sources. Filtrates obtained from biomass of pure cultures grown (72 h) in Potato Dextrose Broth were reacted with 1 M ferric chloride solution. A change in coloration monitored by ultraviolet-visible spectrophotometer (200-600 nm) as compared with control (ferric chloride solution) indicated a positive result. Nanoparticle synthesized in the reactive filtrate was characterized using utltraviolet-visible spectroscopy and Fourier transform infrared spectroscopy (FTIR). The effects of some physical parameters such as agitation, pH and temperature were monitored. The UV-vis spectrum revealed the peak of absorbance of synthesized nanoparticle by selected Trichoderma species at 275 nm. Optimum conditions for nanoparticle biosynthesis were observed at pH 4.5, 35 °C and when cells were agitated. Peaks of transmittance were observed at 950, 1800, 2250, 3000 and 3500 cm−1. These peaks represent the C-H, C=O, C=N, C=H and the OH functional groups respectively. The presence of the alkene, carboxyl and phenol groups suggests a capping of the NPs by the organism after redox reaction. The properties of extracellular iron nanoparticles synthesized by Trichoderma species from this study, presents the fungi as a bioresource for synthesis of stable NPs.
Numerical Study on the Extreme Impact Load of Wavy-Water Ditching
Authors: Zhao Yunke , Qu Qiulin , Liu Peiqing
Published: June 2020

In this paper, numerical method is used study the extreme impact load and its physical causes during the wavy aircraft ditching. the finite volume method and VOF method are used to capture the free surface, six degrees of freedom model and global motion mesh to deal with the relative motion between water and aircraft. and simulate the forced landing process of the aircraft. By choosing the place with the largest vertical velocity relative to the water as the impact position, the extreme impact load on the fuselage is predicted. In this paper, during the impact stage of the wavy water surface, the fuselage encountered an impact peak which is unforeseen on the calm water surface, and the magnitude of the impact peak was related to the sinking speed of the aircraft relative to the water surface. This paper also compares the movement attitude and overload history of aircraft ditching under five sea conditions with different wave height, and gives the influence rules of wave height on the extreme impact load and the peak values of other parameters, which provides a reference for the design of aircraft load distribution.
Numerical Simulation of the Aerodynamic Performance of the Backswept Blade of a Propeller at High Altitudes
Authors: Chen J M , He G Y , Wang Q , Chen L S
Published: June 2020

In high-speed situations, propeller efficiency drops rapidly after the design point is surpassed, and propeller performance deteriorates sharply; thus, high-altitude, long-endurance unmanned aerial vehicles (UAVs) cannot readily meet the design requirements of fast climbing and rapid maneuvering. The design method of the swept blade is investigated to solve this problem. The three-dimensional Reynolds averaged Navier-Stokes (RANS) equations are solved based on the periodic boundary conditions and multiple reference frame (MRF) models to simulate the aerodynamic properties of unswept and swept blades. The results show that the swept-blade propeller can provide a larger thrust than the unswept-blade propeller and that the velocity range with acceptable efficiency is extended after the design point is surpassed. The sweep design method used in this paper provides a reference for the propeller design of high-altitude, long-endurance UAVs.
Numerical Study on the Aerodynamic Performance of the Rigid and Corrugated Forewing of Dragonfly in Flapping Flight
Authors: Song H , He G Y , Wang Q , Chen L S
Published: June 2020

The dragonfly flapping flight as a kind of important flight model, in order to explore the aerodynamic effect on the forewing of dragonfly in flapping. Based on the real dragonfly wings(with corrugation 3D forewing), this paper uses X-flow software numerical simulation for the model, analyzed the influence of different flow velocity and frequency on the aerodynamic effect of the forewing of dragonfly. When the dragonfly flies forward stably, the results show that it has a higher lift with the increase of inflow velocity and flapping frequency. The leading edge vortex (LEV) of the dragonfly’s forewing does not fall off in a flapping period, and the maximum positive lift is generated in the downstroke. When the trailing edge vortex is strong, the peak value of thrust coefficient appears in the process of flapping, and the energy of the trailing edge vortex may provide the thrust for the dragonfly forward flight.
An Engineering Method for Computing the Aerodynamics Performance of Hypersonic Vehicle
Authors: Wang L , He G Y , Wang Q , Chen L S
Published: June 2020

For fast and automatic calculation of aerodynamic in conceptual design of hypersonic vehicles, an aerodynamic fast calculation program based on C/C++ is compiled in this paper. In this paper, the HL-20 lift body and the double radial ball model are selected for the example verification, and the calculation results are compared with the wind tunnel experimental data, it is shown the calculation results is highly consistent with the experiment. The program not only can accurately predict the aerodynamic characteristics of hypersonic vehicles, but also be linked to the optimization program as a C++ library file to realize the shape optimization design.
Three-Dimensional Reconstruction of Continuous Tomographic ICT Images of Defective SRM
Authors: Zhang Ze , Gao Feng , Zhang Qian
Published: June 2020

As an advanced technology for non-destructive testing of defective SRM, industrial computed tomography can visually show the structure of the SRM’s transverse section. 3D reconstruction of continuous tomographic images technology can convert the 2D images obtained into 3D visualization models, thus accurately determine the size and distribution of internal defects in the SRM, etc. Study the main technical methods of 3D reconstruction, it mainly includes 2D images denoising, edge detection and gray-scale image segmentation. Project, accumulate and render the pre-processed 2D images to obtain the 3D model, and then smooth the surface of the 3D model, the end result is a clear reconstruction model. The reconstructed 3D model can provide efficacious data support for SRM non-destructive testing, making the testing results more real and effective.
Aerodynamic Coefficients Prediction for 122 mm Rocket by Using Computational Fluid Dynamics
Authors: Tun N L , Thuri M , Minnzinoo  , Li Z
Published: June 2020

In this study, the Computational Fluid Dynamics code in SolidWorks was used to predict the aerodynamic coefficients of 122 mm rocket in order to get more accurate aerodynamic coefficients and derivatives for flight simulation. This paper presented the governing equations of fluid dynamics applied in SolidWorks and developed the computational model of the rocket. The results were compared against calculated data from an empirical method. The conducted analyses showed that the comparison results are nearly the same. However, the empirical method provided a faster way to obtain results.
Effects of a Splitter and an Endplate on Flow-induced Vibration Characteristics of Cantilevered Rectangular and D-section Prisms
Authors: Ahmad Barata La Ode , Kiwata Takahiro , Kono Takaaki , Ueno Toshiyuki
Published: June 2020

The effects of a splitter and an end plate on the flow-induced vibration characteristics of cantilevered rectangular and D-section prisms with the different finite lengths (aspect ratios L/H) and depth ratios (side ratio D/H of 0.2 and 0.5) have been investigated in a water tunnel. In order to suppress the alternating vortex shedding in the wake of buff bodies, a splitter plate was installed behind the prisms with a small gap and sufficient length to prevent vortex shedding intrusion. Meanwhile, to maintain a two-dimensional flow structure, an endplate was attached to the prism tip end. Mounting the splitter plate enhanced the response amplitude for all prisms. In this case, interferences of amplitude signal spectra for the period of displacement vanished on the prism with a side ratio of 0.5 yielding a uniform waveform on response amplitude. The attached endplate does not take an important role in enhancing the dynamic response of the prisms with a side ratio of 0.5 but it suppressed the response amplitude of prisms with D/H = 0.2.
The influence of temperature on the mechanical properties of polycrystalline and single-crystalline Ni3Al
Authors: Kuang T F , Qin H B , Liu F M , Li Q , Yue X , Gao H T , Yi Y Y
Published: June 2020

Because of the excellent mechanical property at high temperature, single-crystalline Ni3Al-based alloys, which belong to Ni-based superalloys, are widely adopted in the fields of aerospace, aviation and military. Usually, single-crystalline Ni-based alloys are bonded or welded together by polycrystalline Ni-based alloys. In this study, the Young’s modulus, shear modulus, bulk modulus, and Poisson ratio of polycrystalline Ni3Al at the temperature ranging from 10 °C to 850 °C were calculated according to Voigt–Reuss approximation, and the relationships between the mechanical properties and the temperatures were clarified. Moreover, the influence of temperature on the universal anisotropy index and mechanical properties of single-crystalline Ni3Al was evaluated. Results show that, except for Poisson ratio, the increase of temperature linearly decreases the mechanical properties of polycrystalline Ni3Al, while it increases the universal anisotropy index of the single-crystalline Ni3Al. Moreover, different with the bulk modulus, the Young’s modulus and shear modulus of single-crystalline Ni3Al are obvious anisotropic, and their anisotropic characteristics are quite opposite. The increasing temperature decreases both maximum and minimum values of Young’s modulus, shear modulus, and bulk modulus of single-crystalline Ni3Al.
Effect of different microstructure on dynamical stab-resistant property of TA15 alloy
Authors: Ruining Wang , Ruijun Sun , Lingjie Yu
Published: June 2020

The effects of different microstructure on the dynamical stab-resistant property of TA15 alloy are investigated. The specimens were tested on the stab apparatus after heat treatment at temperature of 850, 930 and 1030°C, time of 30min and air cooled. The impact force-time curves, microstructure and fracture morphology of specimens were analyzed. The results showed that the properties of higher strength and plasticity are benefit to the performance of stab resistance of TA15 specimens, and the curves of 930°C and 850°C exhibit two peaks and longer time ranges, but the curve of 1030°C exhibits the shortest time to reach the peak of impact force, and the specimens heat treated at 850°C exhibit the better performance against the knife impactor because of fine grain and stronger grain boundary binding force to absorb the impact force energy.
Mechanical Behavior Analysis of Stainless Steels Subjected to Uniaxial Stress Tests
Authors: Brnic J , Krscanski S , Brcic M
Published: June 2020

The fundamental problem considered in this paper is the choice of materials, in this case stainless steels, for a particular industrial purpose. The choice of the appropriate material should be made based on the material behavior database established by experimental investigations. The mechanical behavior and mechanical properties of several stainless steels, such as ferritic, martensitic and austenitic stainless steels are investigated and analyzed in this research. Mechanical properties at room and high temperatures, creep behavior at different high temperatures and different stress levels as well as Charpy fracture impact energy were considered for several of the steels mentioned. Fracture toughness, based on the Charpy impact energy is calculated using known analytical procedure. In this sense, material properties are determined based on displayed engineering stress-strain diagrams while material creep behavior is displayed in the form of creep curves. Some of numerical values regarding the ultimate tensile strength, measured at room temperature, are given using the following order and in the following form: [σm, Mat.Nr
]20°C. In this sense, the stress levels of the u are: [9251.4122; 7821.4034; 7261.4305; 6861.4841; 5851.4762; 6071.4541]20°C.
Utilisation of Eggshell Powder (ESP) as Partial Replacement of Cement Incorporating Superplasticizer
Authors: Vasudevan Gunalaan , Chan Wei Seah
Published: June 2020

This research showed the results of experiments evaluating the use of eggshell powder from egg production industry as partial replacement for ordinary Portland cement. Research on the reuse of waste materials in the concrete industry has been quite intensive in the past decade. The objective of this research is to identify the performance of dried eggshell powder as a partial cement replacement in the production of concrete. Eggshell powder of various amounts, namely 5%, 10%, 15% and 20% by volume, was added as a replacement for ordinary Portland cement. The results showed that eggshell concrete greatly improved the compressive and flexural strength of concrete. The rate of water absorption of eggshell concrete was reduced as eggshell powder filled up the existing voids, making it more impermeable. However, the compressive strength of the eggshell concrete decreases gradually when the amount of eggshell powder increased. It can be concluded that the optimum percentage of dried eggshell powder as a partial cement replacement is 15%. In this direction, an experimental investigation of ultrasonic pulse velocity, rebound hammer concrete test, compressive strength, flexural strength and FTIR spectra and TGA analysis was undertaken to use eggshell powder and admixtures as partial replacement for cement in concrete.
Direct measurement methods of density matrix of an entangled quantum state
Authors: Turek Yusuf
Published: June 2020

In general, the state of a quantum system represented by the density operator and its determination is a fundamental problem in quantum theory. In this study, two theoretical methods such as using postselected measurement characterized by modular value and sequential measurements of triple products of complementary observables to direct measurement of matrix elements of density operator of a two photon entangled quantum state are introduced. The similarity and possible feasibilities of those two methods are discussed by considering the previous theoretical and experimental works.
Jump formulas for singular integrals and layer potentials on rectifiable sets
Authors: Tolsa Xavier
Published: June 2020

In this paper the jump formulas for the double layer potential and other singular integrals are proved for arbitrary rectifiable sets, by defining suitable non-tangential limits. The arguments are quite straightforward and only require some Calderón-Zygmund techniques.