The investigation of basic microfluidic elements in LTCC structures

2018 ◽  
Vol 35 (3) ◽  
pp. 133-138
Author(s):  
Darko Belavic ◽  
Andraž Bradeško ◽  
Hana Uršič
Keyword(s):  
Cross Section ◽  
Significant Influence ◽  
Research Work ◽  
Applied Pressure ◽  
Microfluidic Devices ◽  
Polymer Materials ◽  
Hydrodynamic Resistance ◽  
Content Type ◽  
Micro Channels ◽  
Fluid Properties

Purpose The purpose of this study is to design, fabricate and investigate low-temperature co-fired ceramic (LTCC) structures with integrated microfluidic elements. Special attention is paid to the study of fluid properties of micro-channels and microvalves, which are important constitutive parts of both, microfluidic systems and individual microfluidic devices. Design/methodology/approach Several test patterns of fluid channels with different geometry and different types of valves were designed and realized in LTCC technology. All test structures were tested under the flow of two fluids (liquids): water and isopropyl alcohol. Flow rates at different applied pressure were measured and hydrodynamic resistance and diode effect were calculated. Findings The investigation of the channels showed that viscosity of fluidic media has significant influence on the hydrodynamic resistance in channels with rectangular cross-section, while this effect is small on channels with square cross-section. The viscosity also has a decisive influence on the diode effect of different shape of valves, and therefore, it is important in the selection of the valve in practical applications. Research limitations/implications In this work, the investigation of hydrodynamic resistance of channels and diode effect of passive valves is limited on selected geometry and only on two fluidic media and two applied pressures. All these and some other parameters have a significant influence on fluidic properties, but this will be the topic of the next research work, which will be supported by numerical modelling. Practical implications The presented results are useful in the future designing process of LTCC-based microfluidic devices and systems. Originality/value Microfluidic in the LTCC structures is an unconventional use of this technology. Therefore, the fluid properties are relatively unsearched. On the other hand, the global use of microfluidic devices and systems is growing rapidly in various applications. They are mostly made by polymer materials, however, in more demanding applications; ceramic is a useful alternative.

Finite element simulation on the relationship between pressure and displacement for the waist of elastic pantyhose

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rui Dan ◽  
Zhen Shi
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Research Work ◽  
Lumbar Vertebrae ◽  
Objective Evaluation ◽  
Quadratic Equation ◽  
New Method ◽  
Content Type ◽  
Displacement Distribution ◽  
The Relationship

PurposeObjective appraisal of pressure comfort is the key point of optimal designing of clothing. The purpose of this paper is to study a new method to provide pressure comfort for the waist of elastic pantyhose through the relationship between pressure and displacement using the finite element method (FEM).Design/methodology/approachThis paper presented a simulation model of the waist cross section consisting of three parts, namely skin, soft tissue and lumbar vertebrae, respectively, according to CT scan. The finite element the model of waist cross-section was established using Mimics software. The pressure–displacement quadratic equation can be obtained using ANSYS software and fitting curves. Meanwhile, we divide the waist cross-section into 12 equal regions according to angle, and then the area shrinkage mass of the waist cross-section can be calculated, respectively.FindingsIn this research work, we got the displacement distribution trend of elastic pantyhose at the waist cross section according to the area shrinkage mass of 12 regions, and this displacement could be used as an objective evaluation index for pressure comfort. All these solutions supply a theoretical reference for optimal design of the women's elastic pantyhose.Originality/valueThe paper analyzed the relationship between pressure and displacement for the waist of elastic pantyhose using FEM, and then got the displacement distribution trend of elastic pantyhose at the waist cross section according to the area shrinkage mass of different regions. It can supply a new method to appraise pressure comfort.

Factors affecting employee performance of PT.Kiyokuni Indonesia

2017 ◽  
Vol 59 (4) ◽  
pp. 602-614 ◽  
Author(s):  
Suharno Pawirosumarto ◽  
Purwanto Katijan Sarjana ◽  
Muzaffar Muchtar
Keyword(s):  
Leadership Style ◽  
Significant Influence ◽  
Employee Performance ◽  
Linear Regression Analysis ◽  
Research Work ◽  
Employee Motivation ◽  
Multiple Linear Regression Analysis ◽  
Primary Data ◽  
Content Type ◽  
Factors Affecting

PurposeThis study aims to examine, analyze and explain the influence of leadership style, motivation and discipline to employee performance simultaneously and partially at PT. Kiyokuni Indonesia. Design/methodology/approachThe primary data used in this study come from questionnaire on respondents’ motivation, discipline, leadership style and employee performance. From 451 people as the population, 82 respondents who met the criteria as a sample were chosen by using the Slovin formula. The analytical method used is multiple linear regression analysis using SPSS Version 22. FindingsThe results of this study indicate that there is a positive and significant influence simultaneously between leadership style, employee motivation and discipline on employee performance. The results also show that there is a positive and significant influence partially between leadership style, employee motivation and discipline on employee performance. Discipline is the variable of the most powerful influence on employee performance, so it needs special attention. Originality/valueThe respondents of this research work for a company which generates products through the work of hands (manual work) and aims to promote the products in the international market.

Study on flexural performance of fabricated natural fiber hybrid polypropylene composite: an experimental investigation through designed experiments

2019 ◽  
Vol 16 (3) ◽  
pp. 389-400
Author(s):  
Rajendra Kumar ◽  
Ravi Pratap Singh ◽  
Ravinder Kataria
Keyword(s):  
Flexural Strength ◽  
Natural Fiber ◽  
Fiber Type ◽  
Flexural Modulus ◽  
Research Work ◽  
Polymer Materials ◽  
Wood Powder ◽  
Content Type ◽  
Fiber Loading ◽  
Fiber Size

Purpose This paper aims to investigate the flexural properties i.e. the flexural strength and the flexural modulus under the influence of selected input variables, namely; fiber type, fiber loading and fiber size in fabricated natural fiber polymeric composites through using Taguchi’s design of experiment methodology. Design/methodology/approach The Taguchi’s design of experiment approach has been used to scheme a suitable combination to fabricate the polymeric composites. Pure polypropylene (PP) has been chosen as a matrix material, whereas two types of fibers, namely; wood powder (WP) i.e. sawdust and rice husk powder (RHP), have been used as a reinforcement in the matrix. Microstructure analysis of fabricated and tested samples has also been evaluated and analyzed using a scanning electron microscope. This analysis has divulged that at moderate fiber size and higher fiber loading, no gap or cavities presented between the fillers and matrix particles, which illustrates the good interfacial bonding between the materials. Findings The flexural strength of the wood powder pure polypropylene (WPPP) composite decreases if the fiber content gets increased beyond 20 Wt.%. In addition, the flexural strength of hybrid composite (WPRHPPP) has been revealed to get improved more in comparison to composites with single fiber as reinforcement. Furthermore, the flexural modulus of WPPP composite has also increased with the increase in fiber loading. It has been concluded that reinforcement size plays an imperative role in influencing the flexural modulus. The optimum parametric setting for the flexural strength and the flexural modulus has been devised as; fiber type – WPRHP, fiber loading – 10 Wt.% and fiber size – 600 µm; and fiber type – WP, fiber loading – 30 Wt.% and fiber size – 1,180 µm, respectively. The microstructure images clearly revealed that during conducted flexural tests, some particles get disturbed from their bonded position that mainly represents the plastic deformation. Social implications The fabricated polymer materials proposed in the research work are green and environmentally friendly. Originality/value The natural fiber-based composites are possessing wide-spread requirements in today’s competitive structure of manufacturing and industrial applications. The fabrication of the natural fiber-based composites has also been planned through the designed experiments (namely; Taguchi Methodology- L9 orthogonal array matrix), which, further, makes the analysis more fruitful and qualitative too. The fabricated polymer materials proposed in the research work are green and environmentally friendly. Shisham WP has been rarely used in the past researches; therefore, this factor has been included for the present work. The injection molding process is used to fabricate the three different polymer composite by varying the fiber weight percentage and fiber size.

scholarly journals The use of rapid prototyping techniques (RPT) to manufacture micro channels suitable for high operation pressures and μPIV

2016 ◽  
Vol 22 (1) ◽  
pp. 67-76 ◽  
Author(s):  
Josep Farré-Lladós ◽  
Jasmina Casals-Terré ◽  
Jordi Voltas ◽  
Lars G. Westerberg
Keyword(s):  
Fluid Flow ◽  
Rapid Prototyping ◽  
Cross Section ◽  
Flow Behavior ◽  
Micro Channel ◽  
Uv Curable ◽  
Micro Manufacturing ◽  
Content Type ◽  
Micro Channels ◽  
3D Printers

Purpose – This paper aims to present a new methodology to manufacture micro-channels suitable for high operating pressures and micro particle image velocimetry (μPIV) measurements using a rapid-prototyping high-resolution 3D printer. This methodology can fabricate channels down to 250 μm and withstand pressures of up to 5 ± 0.2 MPa. The manufacturing times are much shorter than in soft lithography processes. Design/methodology/approach – The novel manufacturing method developed takes advantage of the recently improved resolution in 3D printers to manufacture an rapid prototyping technique part that contains the hose connections and a micro-channel useful for microfluidics. A method to assemble one wall of the micro-channel using UV curable glue with a glass slide is presented – an operation required to prepare the channel for μPIV measurements. Once built, the micro-channel has been evaluated when working under pressure and the grease flow behavior in it has been measured using μPIV. Furthermore, the minimum achievable channels have been defined using a confocal microscopy study. Findings – This technique is much faster than previous micro-manufacturing techniques where different steps were needed to obtain the micro-machined parts. However, due to current 3D printers ' resolutions (around 50 μm) and according to the experimental results, channels smaller than 250-μm2 cross-section should not be used to characterize fluid flow behaviors, as inaccuracies in the channel boundaries can deeply affect the fluid flow behavior. Practical implications – The present methodology is developed due to the need to validate micro-channels using μPIV to lubricate critical components (bearings and gears) in wind turbines. Originality/value – This novel micro-manufacturing technique overcomes current techniques, as it requires less manufacturing steps and therefore it is faster and with less associated costs to manufacture micro-channels down to 250-μm2 cross-section that can withstand pressures higher than 5 MPa that can be used to characterize microfluidic flow behavior using μPIV.

Identifying factors affecting the acceptance of government to government system in developing nations – empirical evidence from Nepal

2020 ◽  
Vol 14 (2) ◽  
pp. 283-303 ◽  
Author(s):  
Shyan Kirat Rai ◽  
Krithi Ramamritham ◽  
Arnab Jana
Keyword(s):  
Significant Influence ◽  
Behavioral Intention ◽  
Research Work ◽  
Developing Nations ◽  
Equation Modeling ◽  
Successful Implementation ◽  
Government Officials ◽  
Content Type ◽  
Factors Affecting ◽  
The Government

Purpose This paper aims to examine the factors that might influence the acceptance of government-to-government (G2G) systems in the Government of Nepal (GoN), to enhance the communication for coordination among government agencies. Design/methodology/approach After reviewing the Unified Model for E-Government Acceptance (UMEGA), interviews, focus group discussions with government officials and interviews with the retired senior government officials, a conceptual model has been proposed. The model is empirically tested with 234 responses collected from the government officials working in the central ministries of GoN using the structural equation modeling technique. Findings The result showed that factors considered from UMEGA such as performance expectancy, effort expectancy, facilitating conditions and attitude have a significant influence on the behavioral intention to use the system in the GoN. Also, the identified factors such as a commitment from leadership, awareness among leadership and transparency have a significant influence on the behavioral intention of the users to accept the system. Research limitations/implications The low sample size is one of the major limitations of this research. Practical implications The findings show that the identified factors have a significant influence on the acceptance model and provide useful insights to policymakers, government officials and system developers to achieve the successful implementation of the e-government system in Nepal. The findings can be used by the academicians and e-government practitioners to extend it to other developing nations. Originality/value This research work explores the factors affecting the acceptance of a G2G system in GoN through the modification of the UMEGA model. To the best of the authors’ knowledge, this is a novel research in the context of Nepal, where the implementation of e-government has been analyzed from the perspectives of acceptance models to support the better implementation of e-governance systems.

Performance analysis of micro drill bit with asymmetric helix groove

Circuit World ◽  
2015 ◽  
Vol 41 (1) ◽  
pp. 7-13 ◽  
Author(s):  
Hongyan Shi ◽  
Jiali Ning ◽  
Hui Li
Keyword(s):  
Cross Section ◽  
Research Work ◽  
Excitation Frequency ◽  
Helix Angle ◽  
Future Research ◽  
Response Analysis ◽  
Drill Bit ◽  
Content Type ◽  
Drill Bits ◽  
Micro Drill

Purpose – The purpose of this paper is to present a new method to optimize the micro drill bit based on finite element analysis, and analyze the performance of the asymmetric helix groove micro drill bit and provide a way to conduct the optimization of micro drill bits. Design/methodology/approach – First, the stress and deform of the micro drills were analyzed in ANSYS. Second, the influence of helix angle, web thickness and ratio of flute to land on stiffness was explored. Combining the former two results, a better set of parameters were optimized. Third, the modal analysis and harmonic response analysis of the optimized micro drill bit were analyzed in ANSYS. Finally, an experiment was carried out to verify the performance of the asymmetric helix groove micro drill bit. Findings – The stress and deform of the asymmetric helix groove micro drill bit are not symmetric. The rigidity is getting better with the web thickness increasing in the selected range; while, the rigidity is getting worse with the helix angle and ratio of flute to land increasing in the selected range. The natural frequencies of the optimized micro drill bit are far away from the excitation frequency, and the response displacement is very small under the excitation of the spindle. In the drilling experiment, the optimized micro drill bit performs well. Research limitations/implications – In this paper, the diameter of the asymmetric helix groove micro drill bit was 0.3 mm and the cross-section shape was not considered. The future research work should consider different diameters and cross-section shapes. Originality/value – Analyzing the influence of three main geometry parameters on the rigidity in ANSYS, a better set of parameters were optimized from the analysis results. The drilling experimental results show that this method is of great significance for obtaining the appropriate parameters of asymmetric helix groove micro drill bits.

Study on the relationship between pressure and stiffness coefficient, and elastic elongation of the top part of men’s socks using finite element method

2015 ◽  
Vol 27 (5) ◽  
pp. 751-766 ◽  
Author(s):  
Rui Dan ◽  
Xuerong Fan ◽  
Zhen Shi ◽  
Mei Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cross Section ◽  
Human Body ◽  
Research Work ◽  
Lower Leg ◽  
Elastic Contact ◽  
Stiffness Coefficient ◽  
Content Type ◽  
The Relationship

Purpose – The purpose of this paper is to study a new method to appraise pressure comfort through displacement distribution, and then explore the relationship between pressure and stiffness coefficient, and elastic elongation of the top part of men’s socks using finite element method. Design/methodology/approach – Through 3D body scanning, a biomechanical lower leg cross-section model is constructed for simulating elastic contact between human body and top part of socks. The human body is regarded as an elastomer and the contact between lower leg and top part of socks is elastic contact, displacement distribution tendency under pressure can be obtained using ANSYS, and the elastic elongation of top part of socks after putting on was calculated based on the displacement values. In this research work, the authors discuss in details with the relationship between pressure and stiffness coefficient, and elastic elongation of top part of socks. Findings – In this research work, the mathematical equation of pressure is obtained which describe the relationship between pressure and stiffness coefficient, and elastic elongation of top part of socks. The results indicated that the predictive values of pressure show good agreement with measured ones after χ2 test. All these solutions supply a theory basis for forecasting of the clothing pressure. Research limitations/implications – This paper is unconcerned with the simulating of pressure distribution and variation trend when dressing during the course of walking and running. Originality/value – The paper provides a finite element simulation model of lower leg cross-section located at the top part of men’s socks, and study the relationship between pressure and stiffness coefficient, and elastic elongation of top part of socks. It can supply a new method to appraise pressure comfort.

scholarly journals Nanomechanical Molecular Mass Sensing Using Suspended Microchannel Resonators

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3337
Author(s):  
Alberto Martín-Pérez ◽  
Daniel Ramos ◽  
Javier Tamayo ◽  
Montserrat Calleja
Keyword(s):  
Molecular Mass ◽  
Mass Density ◽  
Applied Pressure ◽  
Atomic Mass ◽  
Liquid Sample ◽  
Mass Sensing ◽  
Average Molecular Mass ◽  
Fluid Properties ◽  
Molecular Masses ◽  
Microchannel Resonators

In this work we study the different phenomena taking place when a hydrostatic pressure is applied in the inner fluid of a suspended microchannel resonator. Additionally to pressure-induced stiffness terms, we have theoretically predicted and experimentally demonstrated that the pressure also induces mass effects which depend on both the applied pressure and the fluid properties. We have used these phenomena to characterize the frequency response of the device as a function of the fluid compressibility and molecular masses of different fluids ranging from liquids to gases. The proposed device in this work can measure the mass density of an unknown liquid sample with a resolution of 0.7 µg/mL and perform gas mixtures characterization by measuring its average molecular mass with a resolution of 0.01 atomic mass units.

Zn diffusion and reflow behaviour of Sn-9Zn and Sn-8.5Zn-0.5Ag-0.01Al-0.1Ga solders on a Ni/Cu substrate under IR reflow

2014 ◽  
Vol 26 (2) ◽  
pp. 87-95 ◽  
Author(s):  
J. Mittal ◽  
K.L. Lin
Keyword(s):  
Theoretical Calculations ◽  
Research Work ◽  
Content Type ◽  
Diffusion Behavior ◽  
Zn Diffusion ◽  
Cu Substrate ◽  
Practical Applications ◽  
Substrate Interface ◽  
Solder Balls ◽  
Practical Implications

Purpose – This paper aims to compare the reflow and Zn diffusion behaviors in Sn-Zn and Sn-8.5Zn-0.5Ag-0.01Al-0.1Ga (5E) solders during soldering on a Ni/Cu substrate under infrared (IR) reflow. The study proposes a model on the effect of various elements particularly Zn diffusion behavior in the solders on the formation of intermetallic compounds (IMCs). Design/methodology/approach – The melting activities of two solders near their melting points on copper substrates are visualized in an IR reflow furnace. Reflowed solder joints were analyzed using scanning electron microscope and energy dispersive X-ray spectroscopy. Findings – Reflow behaviors of the solders are similar. During melting, solder balls are first merged into each other and then reflow on the substrate from top to bottom. Both solders show a reduced amount of Zn in the solder. Theoretical calculations demonstrate a higher Zn diffusion in the 5E solder; however, the amount of Zn actually observed at the solder/substrate interface is lower than Sn-9Zn solder due to the formation of ZnAg3 in the solder. A thinner IMC layer is formed at the interface in the 5E solder than the Sn-Zn solder. Research limitations/implications – The present work compares the 5E solder only with Sn-Zn solder. Additional research work may be required to compare 5E solder with other solders like Sn-Ag, SnAgCu, etc. to further establish its practical applications. Practical implications – The study ascertains the advantages of 5E solder over Sn-Zn solder for all practical applications. Originality/value – The significance of this paper is the understanding of the relation between reflow behavior of solders and reactivity of different elements in the solder alloys and substrate to form various IMCs and their influence on the formation of IMC layer at solder/substrate interface. Emphasis is provided for the diffusion behavior of Zn during reflow and respective reaction mechanisms.

Global food safety: determinants are Codex standards and WTO's SPS food safety regulations

2014 ◽  
Vol 11 (2) ◽  
pp. 176-191 ◽  
Author(s):  
Rajneesh Mahajan ◽  
Suresh Garg ◽  
P.B. Sharma
Keyword(s):  
Food Safety ◽  
Research Work ◽  
The Body ◽  
Successful Implementation ◽  
Processed Food ◽  
Food Sector ◽  
Content Type ◽  
Safety Regulations ◽  
Food Safety Regulations ◽  
Global Food

Purpose – The purpose of this paper is to investigate perspective in explaining how global food safety can be created through stringent implementation of Codex and World Trade Organization (WTOs) Sanitary and Phytosanitary food safety regulations and suggests the appropriate food safety system for India. Design/methodology/approach – The study has been deployed a survey questionnaire using a sample of Indian Processed food sector. In order to collect data 1,000 supply chain professional were contacted for seeking their consent to be part of the survey. Whereas total responses collected were 252 from Delhi and NCR, with response rate 25.2 percent. The data collected was empirical tested using descriptive statistics, correlation analysis, regression and ANOVA. Findings – The results and discussions indicate that all the global food safety norms laid down by WTO such as goods manufacturing practices, good hygienic practice, hazard analysis critical control point, has been developed to embody principles of safe food processing sector globally. India has also developed their food safety norms as per laid down principles by WTO. Originality/value – The present research work makes an important contribution to the body of literature on global food safety. The paper has important implications for the processed food sector since it tries to bring out practices which would help in successful implementation of global food safety standards. It is useful for academic food research as well as for processed food corporate.

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