International Journal of Materials and Product Technology (22 papers in press)
Characterization of Silica Derived from Rice Husk Ash and Nickel Oxide at Different Composition and Temperatures
by Rizamarhaiza Muda, Sufizar Ahmad, Mohd Azham Azmi, Nooriati Taib, Hariati Taib
Abstract: Nickel supported on silica (SiO2) porous bodies have been found to be active for hydrogen and carbon in gas catalyst applications. In this study, the compatibility of naturally derived SiO2derived from rice husk ash (RHA) and nickel oxide (NiO) at variable compositions and temperatures were highlighted. The compositions of SiO2involved in this study were 50wt% and 90wt% sintered at temperatures of 800
Keywords: rice husk ash; RHA; silica; nickel oxide; polyvinyl alcohol; PVA; powder metallurgy; X-ray diffraction; XRD; X-ray fluorescence; XRF; density; sintering temperature; amorphous; crystalline.
OPTIMIZATION OF EDM PROCESS PARAMETERS FOR AA7050-10 (WT) % B4C COMPOSITE THROUGH ARAS, GREY AND TAGUCHI TECHNIQUE
by ARVIND KUMAR, Ram Naresh Rai
Abstract: The growing demand for high strength-to-weight ratio material has raised the interest to develop Al/B4C composite. Nevertheless, these materials are hard to machine through the conventional machining process. Therefore, to obtain close tolerance for machined components the selection of non-conventional machining process is desirable. The present paper discusses the development of AA7050-10(wt.) % B4C Composite through flux assisted stir casting method. The developed composite undergone microstructural study to ensure the distribution and incorporation of reinforcement particles into the matrix. Die Sinking Electro Discharge Machine used to machine the developed composite. The Taguchi L16 orthogonal array was used to design the experiment to obtain Material Removal Rate (MRR), Surface Roughness (SR) and Tool Wear Rate (TWR) as machinability measure by considering the concurrent effect of various process parameters. The collected responses were optimised using Additive Ratio ASsessment (ARAS) and Grey Relation Analysis (GRA) and Taguchi Analysis. Analysis of variance (ANOVA) was conducted to identify the significance of each process parameters on the responses. Pulse current of 16 A, pulse on time of 200
Keywords: AA7050-B4C Composite; ARAS; Grey Relation Analysis; EDM; Taguchi; ANOVA.
An Experimental Investigation on the Formation of Burrs in Micro Milling of Zr-based Amorphous Bulk Metallic Glass
by Debajyoti Ray, Asit Baran Puri, Naga Hanumaiah
Abstract: Fabrication of precision micro components demands part quality having burr free edges and acceptable surface finish to comply with its requirements of proper functionality. Machining conditions influence process performances in different ways. The present study examines the effect of cutting parameters like cutting speed, feed per tooth (feed rate) and axial depth of cut on the formation of top burrs and surface finish produced in micro channels made through full immersion micro end milling process carried out on a workpiece made of amorphous bulk metallic glass (BMG). The process modelling has been done based on response surface methodology and parametric analysis has been performed to examine the influence of the process parameters on the process responses, namely the burr size formed in up-milling and down-milling sides and the surface roughness of the bottom surface of the micro-channels. The study also undertakes multiple response optimization analysis that determines the optimal values of the cutting parameters that yield lower burr sizes and lower surface roughness.
Keywords: Micro milling; Burrs; Bulk Metallic Glass; Response Surface Methodology; Desirability function; Multiple Response Optimisation.
WED-Machining Characteristics of Ti6Al4V Alloy based on Central Composite Design
by Manjaiah Mallaiah, Deenashree KN, Basavarajappa S
Abstract: The paper presents the optimization of process parameters during Wire Electrode Discharge Machining (WEDM) of Ti6Al4V (Grade 5) alloy using the response surface methodology (RSM) and desirability approach, as unique set of properties of Ti6Al4V is being increasingly utilized in various industries including biomedical and aerospace. However, due to low thermal conductivity and being highly reactive at elevated temperatures tool wear is a significant problem during conventional machining operations. Hence, WEDM may be a viable alternative in certain applications when machining titanium alloys. In this investigation the effect of WEDM process parameters such pulse on time, pulse off time, servo voltage and wire feed are evaluated for material removal rate (MRR) and surface roughness for Ti6Al4V. Experimentation was conducted according to the response surface based central composite design (CCD). Pulse on time and servo voltage was found to be the most significant parameters affecting the MRR while surface roughness, pulse off time and wire feed were less. Second order empirical models of the MRR and surface roughness were obtained from design expert and multi-objective optimization for maximizing the MRR and minimizing the surface roughness by using a desirability approach. The optimum process parameters were obtained for the selected range of experiments. Confirmation experiments were conducted to validate the empirical models of MRR and surface roughness that indicated that the mathematical models developed are suitable for predicting the response parameters.
Keywords: Central composite design; Desirability approach; MRR; Multi-objective optimization; Surface roughness; Ti6Al4V; WEDM; XRD analysis.
Improving Corrosion Resistance in Sintered 304L Stainless Steel using Shot Blasting
by Pongporn Moonchaleanporn, Sukrit Songkuea, Jamorn Klanpolrang, Phonlasit Payaksak, Kosit Wongpinkaew, Nirut Bunchoo, Ekkarut Viyanit, Anchalee Manonukul
Abstract: Sintering atmosphere conditions can affect the corrosion resistance of sintered 304L stainless steel. In addition, surface modifications can improve surface finish and corrosion resistance. In this study, 304L stainless steel was sintered under nitrogen or argon atmospheres using two different heating rates. Barrelling and zinc shot blasting were applied. Subsequently, all samples were subjected to salt spray testing for determination of their corrosion resistance. Both barrelling and shot blasting decreased the surface porosity and surface roughness. However, barrelling and shot blasting increased surface hardness. For as-sintered samples, sintering in nitrogen atmosphere slightly improved the corrosion resistance. Barrelling slightly increased the corrosion resistance of those sintered in argon atmosphere. Shot blasting significantly improved the corrosion resistance of samples sintered in argon atmosphere. However, shot blasting produced less improvement in the corrosion resistance of those sintered in nitrogen atmosphere.
Keywords: Powder metallurgy; shot blasting; barrelling; salt spray.
Special Issue on: Developments in Additive Manufacturing
Investigations on the melt flow behavior of aluminium filled ABS polymer composite for the extrusion-based additive manufacturing process
by Narendra Kumar, Prashant K. Jain, Puneet Tandon, Pulak M. Pandey
Abstract: In extrusion-based Additive Manufacturing (AM) process, the Melt Flow Rate (MFR) of material plays a significant role in determining the suitable process parameters for printing parts. MFR of the polymers varies on the addition of fillers which eventually leads to alteration in the pre-set values of process parameters. The present study deals with the evaluation of MFR of Aluminium (Al) filled Acrylonitrile Butadiene Styrene (ABS) polymer matrix composite using melt flow index tester for extrusion-based AM process. L16 Taguchi OA method was used to design the experiments considering three factors and four levels. Extrusion temperature, extrusion load and filler loading (wt.% of Al) were considered as the input factors, while MFR was selected as the measured response. Furthermore, the significance of each factor was determined using Analysis of Variance (ANOVA) and Signal to Noise (SN) ratio techniques. Experimental results indicated the improvement in the MFR for 10wt.% Al filled ABS composite. However, the opposite trend in MFR was observed for other combinations of ABS/Al. Based on obtained MFR results, process parameters were established to print parts of developed ABS/Al composite through a customized extrusion-based AM process. The present study may be useful in the fabrication of customized lightweight conductive structures.
Keywords: 3D printing; additive manufacturing; pellet; screw extrusion; melt flow rate; fused deposition modeling; ABS; Aluminium; polymer composite.
Synthesis, Analysis and 3D Printing of Flapping Mechanisms
by Balasubramanian E, Chandrasekhar U, Siva Sakthi Velan S, Lung-Jieh Yang, Sachin Salunkhe
Abstract: This paper presents a methodology for designing of flapping mechanisms and rapid fabrication using 3D printing (3DP) technique for subsequent application in micro aerial vehicles. A key feature of the present study is constraining of the mechanism weight and aerial vehicle size to stipulated limits while optimising the functional features of flap angle, flapping frequency and lift. These contradictory set of requirements are fulfilled through syntheses involving linkage number, linkage type and dimensions. As geometrical features are intricate and the required quantity is small, 3DP techniques of fused deposition modelling and digital light processing (DLP) of photopolymers are used as fabrication options. Assembly integration studies are carried out using 3DP parts and the practical feasibility of the suggested approach as a potential alternative to traditional injection moulding is established. Performance evaluation of the developed mechanism indicates conformance with design intent. The presented methodology demonstrates a novel avenue for rapid realisation of an important class of flapping aerial vehicles that have wide ranging applications in surveillance missions.
Keywords: Flapping frequency; Flap angle; Kinematics; Synthesis; 3D Printing.
Development of light weight multi-rotor UAV structures through synergistic application of design analysis and fused deposition modelling
by Balasubramanian Esakki, Sagar N V S S, Chandrasekhar Udayagiri, Sachin Salunkhe
Abstract: Additive manufacturing (AM) technologies are gaining acceptance for fabricating end-use parts in several sectors and this study focuses on developing AM based approach for gainful development of unmanned aerial vehicles (UAV). Design-freedom and time-compression are synonymous with AM technologies and to realise the same in the development of UAVs, redesigning of the components is imperative. This paper presents a protocol that synergistically combines design iterations and fused deposition modelling (FDM) for developing light-weight structures for multi-rotor UAVs. Rather than employing expensive industry-grade FDM systems, the present study illustrates a fabrication protocol based on desktop 3D printers and affordable FDM filament material of polyactic acid (PLA). Multiple design configurations are analysed and prototyped leading to considerable weight reduction. The resultant operational benefits that are related to lesser part count, lower assembly effort and higher flight duration as compared to the conventional designs are demonstrated through experimental efforts. A customised process for electrochemical deposition of copper-nickel layers over the PLA parts is developed for enhancement in tensile, flexural and impact performance. Findings from this study lead to new vistas for rapid design iterations through an AM centric fabrication process with consequential impact on ever burgeoning UAV domain.
Keywords: Additive Manufacturing; Unmanned Aerial Vehicles; Fused Deposition Modelling; Electrochemical Deposition.
Decision making methodology for the selection of 3D printer under fuzzy environment
by Raghavendra Prabhu Sundarraj, Ilangkumaran Mani
Abstract: The eventual goal of this paper is to assess the proficiency of three-dimensional (3D) printers to produce automotive parts. This work is to label the application of Hybrid- Multi Criteria Decision Making (HMCDM) techniques for resolving the 3D printer selection problem for manufacturing of automotive parts. Fuzzy Analytical Hierarchy Process (FAHP), FAHP- VIseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) and FAHP- ELimination and Choice Expressing REality (ELECTRE) are the MCDM methods used for evaluation and ranking of the 3D printers. Totally ten different 3D printers alternatives such as Lulzbot Taz 5 (Z1), Ultimaker 2 (Z2), Zortrax (Z3), Wanhao Duplicator 4 (Z4), Airwolf 3D AW3D HD2X (Z5), Flashforge creator X (Z6), Makerbot Replicator orginal (Z7), Delta non turbo WASP (Z8), Artifex duo 2 (Z9), UP plus 2 (Z10) and six evaluation criteria such as volume (C1), printing Speed (C2), thickness of the layer (C3) , Extruder(s) (C4), machine cost (C5), cost of the filament material (C6) are motivated in this study to choose the appropriate 3D printer from the alternatives. The fourth alternative Wanhao Duplicator 4 (Z4) has achieved the top spot among the alternatives using the suggested methodologies.
Keywords: 3D printer; MCDM; FAHP; ELECTRE; VIKOR.
Mechanical capabilities of semi-rigid thermoplastics ABS and PLA from 3D printing
by Jaime Molina Osejos, Cesar Ayabaca Sarria, Diana Peralta Zurita, Santiago Gómez Rosero, Gustavo Moreno Jimenez
Abstract: The use of 3D printing is more common in industries, such as textiles, food, aeronautics, automotive, medicine and others, because of its great versatility during the manufacturing process generation of elements or components with high geometric complexity in relatively short time at low cost. This study presents the characterization of semi-rigid Acrylonitrile Butadiene Styrene (ABS) and Polylactic Acid (PLA), which were obtained using both of additive manufacturing and specifically the molten material deposition method. The semi-rigid samples were made with 5 different infill patterns in their interiors: triangle, square, pentagon, circles.
The samples were subjected to tensile and bending tests, which allowed the evaluation of the yield strength, ultimate tensile strength, deformation and modulus of elasticity. Also, ASTM D638-14 and ASTM D790-10 norms were used for methodology validation. The results determined that the distribution of concentric circles with 7,964 MPa / g and 12,234 MPa / g. was the best for PLA and the square with 8.82 MPa / g and 8,994 MPa / g was the best for ABS respectively.
Keywords: ABS; PLA; material characterization; 3D printing; yield strength; deformation.
THE INSERTION OF LOW-COST ADDITIVE MANUFACTURING INTO ENGINEERING TEACHING: A CASE IN CENTRAL MEXICO
by Alberto Saldaña-Robles, Antonio De Jesus Balvantin-Garcia, José Ángel Diosdado-De La Peña, Erick Rojas-Mancera, Noe Saldaña-Robles
Abstract: Recently, multiple industrial sectors have developed a great interest in Additive Manufacturing (AM); as such, a need has been identified for familiarization and training in this area. Hence. efforts to democratize knowledge in this area have been led by multiple educational institutions around the world. On the basis of the evidence on the advantages of AM in education, this paper puts forward a proposal for its use in fostering a proactive, cooperative learning environment with a constructivist vision based on problems and projects. It provides a description of the experiment that began in November 2015 involving engineering students and faculty in the training and use of AM equipment, in particular a 3D printer. In addition, it shows some of the faced problems and solutions implemented during the use of this equipment. Also, several projects are described involving implementation of AM alongside other techniques, such as Computer Aided Design and Finite Element Analysis, on different projects that were both academic and interdisciplinary applied research. Lastly, the paper details the impressions of the students involved in AM and there is a discussion of the positive effects of their participation on their competencies.
Keywords: Low-Cost Additive Manufacturing; Engineering Education; Problem-Based Learning; Project-Based Learning; Computer-Aided Design.
Special Issue on: A Synergistic Approach in IR4.0 for Product Technology Development
Characterisation of microstructure, mechanical properties and fracture mode of the dissimilar joining of AISI 304 stainless steel and DP780 dual phase steel by resistance spot welding
by Masoud Sabzi, Sadegh Moeini Far, Saeid Mersagh Dezfuli
Abstract: Microstructure, mechanical properties and fracture mode were investigated for the dissimilar joining of AISI 304 steel and DP780 steel by resistance spot welding. First resistance spot welding was utilised with a current density of 8 kA, holding time after welding of ten cycles and 5 kN electrode force. Then, to evaluate the microstructure, hardness profile and tensile-shear strength of weld nugget, scanning electron microscopy (SEM), Vickers micro-hardness and tensile-shear tests were carried out, respectively. Microstructural evaluations showed that in the dissimilar joining of DP780-AISI 304 stainless steel, fusion zone (FZ) microstructure was martensitic and some grains were also coarsened in heat affected zone (HAZ). Moreover, HAZ in AISI 304 stainless steel side remained completely austenitic, while HAZ in DP780 dual phase steel transformed to martensite. Micro-hardness results showed that in the dissimilar joint of DP780-AISI 304 stainless steel, FZ hardness was higher than base metals (BMs) of both sheets of steel. Additionally, HAZ in DP780 dual phase steel side had higher hardening ability than other joint areas. Results of tensile-shear tests of the dissimilar joint of DP780-AISI 304 stainless steel, indicated that the joint had the tensile-shear strength of 15 kN along with the occurrence of severe plastic deformation.
Keywords: resistance spot welding; DP780 dual phase steel; AISI 304 stainless steel; microstructure; hardness profile; tensile-shear strength.
Effect of ball milling time on the properties of nickel oxide-samarium-doped cerium composite anodes for solid oxide fuel cells
by Nor Fatina Raduwan, S.A. Muhammed Ali, Mustafa Anwar, Andanastuti Muchtar, Mahendra Rao Somalu
Abstract: The powder characteristics of composites under different processing conditions, such as milling time, must be elucidated before fabricating electrodes with porous structures for fuel cell applications. Milling time is an important parameter in producing pure composite powders with fine crystallite size and affects the densification of the sintered pellet and the electrical performance of the cell. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses were conducted to characterise nickel-oxide-samarium-doped cerium (NiO-SDC) powders milled for different durations (2, 12, and 24 h). Field-emission scanning electron microscopy (FESEM) analysis was performed to clarify the porosity of the sintered pellets. Density was determined using Archimedes method and was found to decrease after the reduction of the anode pellets. The XRD analysis of the composite anodes showed good chemical compatibility between the NiO and SDC. The TEM analysis of the as-prepared powders indicated that the particle size of the powder was within the nanometre range. This finding was confirmed by the FESEM micrograph of the sintered pellets. The porosity of the sintered pellets (before and after reduction) ranged from 20% to 40% and was considered sufficient for anode materials in solid oxide fuel cells (SOFC).
Keywords: ball milling time; NiO-SDC; composite anode; particle size; porosity; density; solid oxide fuel cell; SOFC; sintering; pellet; grain size.
Characterising the strength of solid and honeycomb geometrical plates under quasi-static loading
by Nik Muhammad Azif Arifin, Abdul Hadi Azman
Abstract: This paper presents the strength characteristics of solid and honeycomb plates under quasi-static loading using finite element analysis (FEA). The aim was to investigate and compare the strength characteristics of solid and honeycomb plates. A comparison of these simulations was conducted based on the strength of material characteristics prediction. Geometrical models for the solid and honeycomb plates subjected to uniform stress were developed and assessed. The effects caused by quasi-static load were studied by comparing the two plates to obtain the stress and translational displacement. The simulations were elastic and the deflection of the solid and honeycomb plates were determined. The results were similar with a deflection of 11.4 mm for the solid plate and 11.3 mm for the honeycomb. However, the stress results were different. Therefore, this comparison method is suitable for evaluating other mechanical structures in the field of strength of materials.
Keywords: honeycomb plate; quasi-static; translational displacements; solid plate; von Mises stress.
A systemic study on hydroforming process of exhaust pipe by FE simulation and experiment
by Ning Guo, Kuanxin Liu, Shunqi Zheng, Kemin Xue
Abstract: Hydroforming process of tube parts is widely used in many industries due to the virtues of weight reduction and high strength and stiffness. The exhaust pipe hydroforming process is investigated systemically combining FE simulation with experiments. The FE simulation model for hydroforming process is established after solving several key technologies based on the ABAQUS software, and the validation is carried out compared with experiments. And then, the effects of process parameters on forming quality are studied by using the FE simulation model. The optional process parameters are obtained based on the simulation model and orthogonal experimental analysis. Finally, three typical loading paths are proposed and tested, and the guidance for loading paths is given. Based on these developments, the exhaust pipes are manufactured by hydroforming in a short period at low cost.
Keywords: hydroforming process; exhaust pipe; optional process parameter; orthogonal experimental analysis.
Characterisation of four-layered Al-Al2O3 functionally graded material prepared through powder metallurgy and pressureless sintering
by Farah Fazira Kamaruzaman, Dewan Muhammad Nuruzzaman, Mohammad Asaduzzaman Chowdhury, Siti Nur Sakinah Jamaludin, Shahnor Basri, Noor Mazni Ismail
Abstract: In this research study, four-layered aluminium-aluminium oxide (Al-Al2O3) functionally graded material (FGM) was prepared through powder metallurgy (PM) route considering 0%, 10%, 20% and 30% weight percentage of ceramic concentration. The sintering temperature and time used are 620°C and 120 min following two-step sintering cycle. The prepared FGM samples were characterised by densification and shrinkage. Microstructural and elemental analyses were carried out by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Mechanical characterisation was carried out using Vickers microhardness tests. It was observed that cylindrical FGM specimens (green compact) were successfully prepared and diameter of cylindrical structure was decreased after sintering process. It was also observed that there was no existence of macro-crack or micro-crack within the individual layer or at the interface and smooth transition occurred from one layer to next layer. Elemental analyses confirmed the gradient distribution of material composition layer by layer.
Keywords: characterisation; functionally graded material; FGM; pressureless sintering; aluminium; aluminium oxide.
The weighting of product design specification for a composite side-door impact beam using the analytic hierarchy process method
by Mohd Adrinata Shaharuzaman, S.M. Sapuan, Muhd Ridzuan Mansor, M.Y.M. Zuhri
Abstract: In this study, the analytic hierarchy process (AHP) method is employed to determine the weightage criteria for product design specification (PDS) of a side-door impact beam. Six criteria for PDS have been chosen to be judged using the AHP pairwise comparison technique by ten decision makers from an automotive engineering and product design background. The results show that performance has the highest weightage, which is 0.3566, follows by product cost and weight with the values of 0.1971 and 0.1690, respectively. Environment and disposal are at fourth (0.1127) and fifth (0.0857) places, respectively, whilst size generates the lowest weightage (0.0789). The AHP consistency ratio (CR) also shows the obtained average CR value is below 0.1, which proves that the decision makers' judgement is consistently high. In conclusion, this study indicates that the utilisation of the AHP method can assist in systematically determining the weightage criteria in the MCDM method.
Keywords: analytic hierarchy process; AHP; multiple criteria decision making; MCDM; side-door impact beam; weightage criteria.
Synthesis of carbon nanoparticles from tyre pyrolysis oil using CO2 laser and their characterisation
by Muhammad Mat Junoh, Aminuddin Saat, Farid Nasir Ani
Abstract: The growth of transportation industry has contributed to the increasing number of waste tyre globally. Waste tyre is harmful to the environment and to combat this problem, utilisation of waste tyre is an ideal method. The technology of converting waste tyre into oil using pyrolysis technology has derived researchers involved in the process of transforming pyrolysis oil into value added product. Therefore, in this study, tyre pyrolysis oil (TPO) was used to synthesise carbon nanoparticles (CNPs) using CO2 laser as the main heating source. The experiment was conducted in N2 gas atmosphere at 0.2 l/min flow rate. Temperature and reaction time was set for 400°C, 500°C, 600°C and 5 min, 10 min, 15 min respectively. Different pump speed of 1 rpm, 2 rpm and 3 rpm were applied. From the results, the maximum yield for CNPs synthesised was found at 500°C with holding time of 10 minutes and speed of 3 rpm with 0.0734 grams per cycle. Sample characterisation by FESEM, EDX and XRD has shown that prepared CNPs consist large amount of amorphous structure with size between 40-70 nm in diameter whereas BET surface area was 13.8 m2/g.
Keywords: waste tyre; pyrolysis; tyre pyrolysis oil; TPO; carbon nanoparticles; CNPs; CO2 laser.
Special Issue on: Cambridge Summit 2018 Advances in Engineering Systems and Product Technology
Effect of nano-yttria dispersion on the microstructure and mechanical properties of W-Ni-Co alloys
by Pandi Selva Durai C, Arul Mozhi Selvan Varadappan
Abstract: In this study, effect of nano-Y2O3 (0.25-0.75 wt.%) addition in tungsten heavy alloy which consists of 93wt.% tungsten and Ni/Co ratio fixed at 9 was investigated. Ni, Co and Y2O3were mixed in high-energy ball milling in order to obtain nanostructure and this mixture subsequently blended with tungsten (W) in a low energy ball milling. The powder mixture was consolidated by cold-isostatic pressing (CIP) and the green compact was sintered at 1475
Keywords: Cold isostatic pressing; Contiguity; High-energy ball milling; Nano Y2O3; W-Ni-Co heavy alloy.
Experimental investigations and optimization of process parameters in dry finish turning of Inconel 625 super alloy
by S. Hemakumar, P. Kuppan
Abstract: This study presents an experimental investigation and optimization of process parameters in finish dry turning of Inconel 625 nickel based super alloy. The process parameters such as cutting speed and feed rate were varied for three levels keeping depth of cut constant at finish machining regime (0.5 mm). The experiments were conducted as per the full factorial design of experiments and the influence of process parameters on the output measures such as cutting force (FC), feed force (Ff), average surface roughness (Ra) and average flank wear (VB), were analyzed using ANOVA. Empirical models were developed for the output measures using Response Surface Methodology and the regression analysis shows a good degree of fit. The optimal conditions for minimum Ra and VB were obtained through response optimization Composite Desirability approach. Furthermore the tool wear mechanism was studied and reported.
Keywords: composite desirability approach; dry machining; cutting force; Inconel 625; response surface methodology; surface roughness; tool wear.
Random Dopant Fluctuations Impact reduction in 7 nm Bulk-FinFET by Substrate Engineering
by Jegadheesan V, Sivasankaran K, Aniruddha Konar
Abstract: Currently Fin-Field-Effect-Transistors (FinFETs) are used at 7 nm technology node, in order to avoid parasitic leakage channel under the controlled channel Punch-Through-Stopper (PTS) doping is used with the bulk Silicon substrate (PTS-Si substrate). The dopants from PTS doping enters into the channel during the annealing process and increases channel doping level. The increased doping concentration in channel causes undesirable effects such as reduction in channel mobility and increase in Random-Dopant-Fluctuations (RDFs). Using a Silicon-On-Insulator substrate (SOI substrate) is a costlier solution, this work presents Super-Steep-Retrograde-Silicon substrate (SSR-Si substrate) as a better solution for this problem. In this work, the SSR-Si substrate is achieved by placing lightly doped 10 nm thick SSR-buffer layer (Silicon) on top of PTS-Si substrate. This SSR-buffer layer captures dopants intruding from PTS doping into channel thereby achieves SSR doping profile in the channel. The results show SSR-Si substrate reduces the RDF induced threshold variations by 50%, it also provides better DC and RF/analog metrics than PTS-Si substrate and comparable with SOI substrate.
Keywords: FinFET; RDF; SIFM; Statistical variations;.
Coupling reduction of two element MIMO Antenna using parasitic element for LTE Band Application
by A.Christina Josephine Malathi, Thiripurasundari D
Abstract: This paper presents a two triangular patch MIMO antenna using parasitic element for enhancing isolation which is aimed to function in the LTE band covering from 1.7 to 3.6 GHz. The parasitic element is a planar interdigital line structure placed between the patches on top of the substrate. The antenna covered an impedance bandwidth of (1.5 to 3.58) GHz with return loss of -18.16 dB and -12 dB at 2.26 and 3.25 GHz during simulation. A fractional bandwidth of 92% was achieved. An isolation of -20 dB and -20.5 dB was observed during simulation at 2.26 GHz and 3.25 GHz. The proposed antenna was fabricated and tested. It provided a bandwidth of (1.8 to 2.27) GHz & (3.2 to 3.3) GHz with return loss of -18.28 dB and -10.64 dB respectively. An isolation of -25.5 dB at 2.26 GHz and -20.5 dB at 3.25 GHz was observed during measurement amid the ports with a close by spacing of 0.074λ between antenna elements. With a very close by spacing the proposed antenna exhibits a better performance compared to the previously reported designs in the literature by providing 53.3% less space. The antenna had good radiation characteristics in both E-plane and H-plane for all the operating frequencies.The simulated envelope correlation coefficient is below 0.002 and the total active reflection coefficient is below 0.40 throughout the band with a gain of 2.28 dB and 4.30 dB during simulation and 2 dB & 3.23 dB in measurement at 2.26 and 3.25 GHz.
Keywords: Gain; long-term evolution (LTE); envelope correlation coefficient (ECC); return loss; multiple input multiple output (MIMO); Total Active Reflection Co-efficient (TARC).