The purpose of this study is to optimize the coupling efficiency of an optical fiber lens by applying the uniform design of experiments and Kriging interpolation methods. A third-generation optical fiber endface polishing machine is applied to polish the optical fiber endfaces into oval shapes. A type-36 optical fiber fusion splicer is used to fuse the optical fibers into a lens. In the polishing process, the control factors are polishing angle, feeding rate, and rotation speed. Firstly, the uniform design of experiments method is used to construct a set of experiments. The constructed experiments are scattered uniformly in the design space formed by the control factors. Secondly, the coupling efficiency of the lens in each experiment is measured using a 980 nm laser diode and a power meter. Thirdly, the Kriging interpolation method is used to transform the discrete data of coupling efficiency into a continuous surrogate model of coupling efficiency. Finally, a mixed optimization algorithm combining a global search algorithm, genetic algorithm (GA), and a local search algorithm, Nelder-Mead simplex (NMS) algorithm, is used to optimize the coupling efficiency. The optimal solutions of polishing angle, feeding rate, and rotation speed are 56°, 289 rpm, and 52 μm/rev, respectively. By integrating the uniform design of experiments method and Kriging interpolation method, the coupling efficiency of the optical fiber lens can be improved from 60.89% to 79.63%. The improved rate of the coupling efficiency is 30.8%.
Titania-based coatings on commercially pure titanium (CP-Ti) were formed by micro-arc oxidation in different electrolyte solutions containing anions such as phosphate ( 3 4 PO ) and silicate ( 2 3 SiO ). The surface topography, phases, and elemental compositions of the P-TiO2 and Si-TiO2 coatings were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), and X-ray diffraction (XRD), respectively. Staphylococcus aureus (S. aureus) was used to evaluate the antibacterial properties of the MAO coatings. The experimental results demonstrate that The P-TiO2 coated sample had amorphous phase, main anatase-TiO2, and a small amount of P2O5. However, the Si-TiO2 coated samples were composed of SiO2, anatase-TiO2, and amorphous phase. After 24 h of incubation, the antibacterial activities against S. aureus were 96.4% for the P-TiO2 coated sample and 98.6 % for the Si-TiO2 coated sample.
Dielectrics play a key role during electrical discharge machining (EDM). Kerosene-based oil, deionized water and gas are traditionally used dielectrics in industries. The process performance of micro EDM mainly based on it. The major drawbacks of liquid-based dielectrics are large ratio of electrode wear and pollution. Micro EDM in gas provides almost zero tool wear. However, the discharge gap is very small, which leads to abnormal discharge during machining. The theme of this research work is an investigation of the micro EDM in nitrogen plasma jet (NPJ) performed in magnetic field for enhancing process performance. In this study, the magnetic field is introduced perpendicular to the current direction, for enhancing the material removal ratio and helping in debris distribution from machining area. Series of experiments have been conducted, by varying magnetic field current and voltage. Experimental outcome shows that this adopted approach significantly improves the material removal rate (MRR) as well as surface roughness (Ra). The presence of Lorentz force has no negative impact on electrode wear.
Pyrolysis is explored as a potential cleaner valorization alternative for waste pine-dust and shavings from sawmilling activities in Manicaland, Zimbabwe. The investigation covers the physical and thermochemical characterization of the raw material, pyrolysis using a fixed bed reactor at varying temperatures and subsequent characterization of the products. The ultimate analysis reveals that Pine has a CHNO composition of 45.76%, 5.54%, 0.039% and 48.66% respectively. Thermogravimetry results showed that the residues’ ash, fixed carbon and volatiles matter composition was 0.83%, 20% and 79.16%. The high heating value was found to be 17.57 MJ/kg. Pyrolysis runs were carried out for temperatures of 450, 500, 550 and 600C. Results indicate a maximum yield of bio-oil of 45.7% at a temperature of 500 C, which agrees with literature. Generally, the gas yield increased while the char yield decreased with increase in temperature.
Nowadays, the number of chronic wounds is on the rise. Wounds can caused by many problems such as disease, burn, ulceration, trauma and accident. Tissue engineering aims to produce porous scaffold biomaterials to regenerate damaged tissues to growth of new tissue. This research, gelatin was blended with Carboxymethylcellulose (CMC) in various conditions and fabricated to porous structure by using freezedrying method. All scaffolds were strengthen their structure by dehydrothermal crosslinking. Normally, the scaffold behavior is likely to be a foam-like hyperelastic material. Therefore, this research was selected Blatz-Ko model to describe the material behavior that acts as a foam rubber. This model could apply with both cases of compressible and incompressible material. The mechanical characterization of the scaffold was investigated by compressive test using universal testing machine (UTM). The experimental data obtained from the UTM was used to plot the stress-strain curve. The initial shear modulus of the material was identified by function derived from Blatz-Ko hyperelastic model using non-linear curve fitting method. The result revealed that Blatz-Ko model could fit curve at approximately 7% strain which was suitable for infinitesimal strain theory. The dehydrothermal treated scaffold with 90:10 gelatin/CMC ratio showed the highest shear modulus of 10.47±1.21 kPa. The structural collapse occurred in 60:40 gelatin/CMC scaffold. The physical characterization was done by using scanning electron microscopy (SEM) to investigate surface morphology and pore size of scaffolds. The results showed the appropriate pore size of the scaffold with average pore size of 117 μm to 197 μm. The 90:10 gelatin/CMC scaffold showed the biggest pore size.
This research is based on the concept of smart manufacturing, with the case of a motor manufacturing line. Explore the relationship between the project content in the finished motor data and all processes of pre-engineering, coils, and assembly. The objective of this study is to improve the efficiency of motor quality control inspection. The method is mainly to use expert interviews and secondary data to collect case company data. This study finds that: 1. This research is based on the initial 88 testing items, of which 14 items can be referenced in the motor manufacturing process. 2. This study proposes the relevant parts and production steps corresponding to these 14 items, which can evaluate the error points from the values of the motor finished product inspection items and simplify the time spent in quality control inspection. Finally, this study proposes practical implications and future research recommendations.
In the offshore platform, T-junction has been extensively used as preliminary gas-liquid separator due to its compact design. Frequently, a sudden slug generation causes liquid carryover issues leading to excessive liquid in the gas feed for downstream equipment. Geometry features of T-junction and slug flow are believed to be the root cause of this problem. Based on the literature review, previous works mostly focused on improving two-phase separation in the standard T-junctions without taking into account the impact of inlet flow regime. Moreover, there is no published research on the separation performance of converging T-junction, which is a promising design. The objective of this research is to numerically evaluate the hypothesis that converging T-junction yields better phase separation under slug flow compared with regular and reduced T-junctions. Three-dimensional Computational Fluid Dynamics (CFD) software FLUENT 17.2 and specialized User Defined Functions was utilized to study the evolutionary process of air-water slug flow and its phase separation behavior in converging T-junctions over eight different geometry designs. The incompressible Volume of Fluid (VOF) method was used to capture the transient distribution of segregated gas-liquid interface. The validity of the present model was compared with the experimental data taken from the air-water two-phase flow in 3-inch diameter main pipe of T-junction. The validated model gave a strong foundation to proceed with converging T-junction simulation. The research found that the converging T-junction can increase by upto 20% of separation efficiency compared with regular and reduced T-junction at the same operating conditions. Moreover, the converging T-junction with the main and converging diameter ratio of 0.67 and 0.4, respectively, to be optimal in improving the phase separation over a wide spectrum of air and water superficial velocities.
With the development of the tool machine industry, the precision and quality demand for processing is more exquis-ite, from the traditional industrial manufacturing equipment in the past, to the current development of high-speed, high-pre-cision, high-efficiency intelligent automation tool machine equi-pment, in the face of today's globalization,customerization andenvironmental awareness trend. Taking the vertical milling machine as an example, the feed system drives the machining in the direction of the tool machining to complete the cutting process.The rail c-ontact surfac-e of the feed system is grinding. It produces noise, bad vibration, processing rigidity is reduced, processing accuracy is reduced, friction almost thermal energy is generated, etc. Finally it reduces the service life of the servo motor. In this study, the contact between the slide rail and the slide seat was obtained by using the homemade device to obtain the influence of the contact area of the rail on the thickness of the lubricant. When the same contact area, the oil film thickness of the lower oil injection amount is small. The thickness of the oil film with higher oil injection amount is thicker. When the same oil injection volume, the thickness of the oil film of the larger contact area is small.
—Using mobile charging devices to provide controllable and sustainable energy to Wireless Sensor Networks (WSN), has become an important topic of current research. A novel charging strategy based on the mobile device is proposed to add the net increase in network power. To improve the charging efficiency and avoid unnecessary charging, a charging threshold is evaluated and determined. A Modified Ant Colony Optimization (MACO) is introduced to minimize the travelling distance of the mobile charging device. A dynamic state transition rule, which considers the real-time power of the nodes is developed in MACO to guide the charging path of the mobile charging device. The sustainability of the WSN using the proposed charging strategy is also studied. A WSN model with 50 nodes and one mobile charging device is used to testify the effectiveness and the efficiency of the proposed method. The results demonstrate that the proposed charging strategy can maximize the net increase of the average power of the WSN with a shorter route in one or multiple charging tour and ensure the power supply of the WSN maintaining in a healthy state.
— In this study, carbonitride and nitride coating films were deposited on a cemented carbide ISO K10 using two different (Al, Cr, W, Si)-targets, namely the (Al53, Cr23, W14, Si10)- and (Al58, Cr24.8, W7.2, Si10)-target. In deposition, N 2 gas or (N 2 , CH 4 ) gas was used as the reaction gas, and the substrate DC bias voltage was -150 or -300V. Then the characteristics of the four types of coating films were investigated. ASTM D2 hardened steel was cut with four types of coated cemented carbide tools. The tool wear of the coated tools was experimentally investigated and the following results were obtained: (1) Compared with the wear progress of the (Al58, Cr24.8, W7.2, Si10)N coated tool and that of the (Al58, Cr24.8, W7.2, Si10)(C, N) coated tool, the wear progress of the (Al58, Cr24.8, W7.2, Si10)N coated tool was slightly slower than that of the (Al58, Cr24.8, W7.2, Si10)(C, N) coated tool. (2) In the case of the (Al58, Cr24.8, W7.2, Si10)N coated tools, comparing the two types of the substrate DC bias voltages, the wear progress at the substrate DC bias voltage of -300 V was slower. (3) In the case of the substrate DC bias voltage of the -300V, comparing the wear progress with the (Al53, Cr23, W14, Si10)N coated tool and the (Al58, Cr24.8, W7.2, Si10)N coated tool, the wear progress of the (Al58, Cr24.8, W7.2, Si10)N coated tool was slower. Therefore, as a target material, the (Al58, Cr24.8, W7.2, Si10)-target has excellent wear resistance.
The interfacial heat transfer coefficients (IHTCs) are the key parameters in numerical simulations on casting processes, but the inverse estimation of them from experiments is very difficult to be conducted and involves considerable uncertainty. With the assumptions of isothermal casting and one-dimensional heat conduction, this paper presents a lumped-capacity method for inverse estimation of IHTCs for die casting of high thermal conductivity metals. This method greatly simplifies the procedure of temperature measurements while providing estimation of IHTCs with reasonable accuracy.
Knowledge of using the Ankle foot Orthosis in patients with severe developmental dysplasia of the hip is crucial and may help to improve the gait cycle during walking.This paper aimed to evaluate and study the kinematics and kinetics of the hip joint during walking in the sagittal plane for a patient with severe hip dislocation age 26 ( the author of this paper) who is experiencing using two different types of ankle-foot Orthosis (Custom-made, and Leaf-AFO).The data were collected using ten cameras and one force plate.We used an inverse dynamic approach to calculate sagittal joint angles, moments and power.The results pointed out that The Custom-Orthosis had a higher moment during the late stance of the gait cycle than that of Barefoot; the data showed significant change by a mean difference of 0.1604 Nm/kg.however, the Leaf AFO Spring Orthosis did not change much the flexion moment during the late stance phase.The paper concluded that both orthosis wearing the custom -made AFO improved the kinetics of the hip joint in special while wearing the custom -made AFO leading to reduce the pain associated with loading during walking.
To achieve the renewable energy target, it is necessary to carry out technological assessment of marine hydrokinetic energy devices. The objective of this study is to present the suitability of existing devices in the established resource sites in Ireland. The analysis is based on the technical data of the turbines and tidal current velocity profiles from the established numerical model. From this study, we conclude that there are certain locations where all kinds of marine hydrokinetic devices could be deployed, while in a few locations’ technology feasibility is limited.
Glass fiber composites were fabricated from two different manufacturing techniques, vacuum infusion and vacuum bag, two resin types (epoxy, vinyl ester), as well as and two fiber combinations (S-glass and E-glass). The analyzed properties were tensile modulus, strength as well as compression strength, with relation to sample morphology and fracture surface due to compression. The results showed that all variables and their interaction did not significantly influence tensile modulus, while manufacturing methods was the only significant variable influenced tensile strength. The results showed that vacuum infusion samples had better tensile strength than those produced by vacuum bag due to less resin and bubbles. In term of compression, the change on strength was highly contributed by resin type and fiber used on layer A. Composites samples with epoxy resin showed better strength than those of vinyl ester may be due to better initial resin property. While, imbalance transfer load and fiber density inhibiting resin penetration and causing resin rich samples produced lower compression strength for samples with S-glass applied to layer A than E-glass. Further analysis on fracture surface showed that most samples failed on compression test due to shear, kink and resin break
