scholarly journals Experimental study on the hole quality during abrasive waterjet drilling of CFRP

2021 ◽  
Vol 13 (2) ◽  
pp. 103-108
Author(s):  
Panagiotis Karmiris-Obratański ◽  
◽  
Nikolaos E. Karkalos ◽  
Dimitrios Skondras-Giousios ◽  
Emmanouil-Lazaros Papazoglou ◽  
...  
Keyword(s):  
Design Method ◽  
Orthogonal Design ◽  
Optical Microscope ◽  
Hole Diameter ◽  
Standoff Distance ◽  
Abrasive Waterjet ◽  
Hole Quality ◽  
Machining Processes ◽  
The Impact ◽  
Abrasive Waterjet Drilling

Abrasive Waterjet (AWJ) machining is considered an excellent alternative to conventional machining processes due to its superb machining characteristics. More specifically, Abrasive Waterjet drilling is nowadays a promising non-conventional process for obtaining high quality holes. In the present study, drilling experiments based on Taguchi L9 orthogonal design method were conducted via AWJ on carbon fiber reinforced polymer (CFRP) plate at various waterjet parameters, namely, different pressure, abrasive mass flow rate and standoff distance values. The purpose of the experiments was to investigate the impact of these process parameters on the quality of holes. The hole quality was determined by measuring the hole diameter error as well as the hole taper. The optical evaluation was implemented with the use of optical microscope and special measuring software. The ANOVA analysis of the results showed a significant influence of standoff distance regarding the hole diameter error and a combined influence of waterjet pressure and standoff distance regarding the hole taper. Furthermore, the optimal process parameter values for the optimization of the hole diameter error and hole taper were determined. The hole quality in terms of defects appearance was also quantitatively inspected, through optical imaging.

Effect of Admixed Recycled Aggregate on Properties of Recycled Concrete

2012 ◽  
Vol 174-177 ◽  
pp. 743-746
Author(s):  
Ya Jun Zhao ◽  
Ying Gao ◽  
Li Li He
Keyword(s):  
Compressive Strength ◽  
Design Method ◽  
Orthogonal Design ◽  
Plain Concrete ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Influence Of Water ◽  
The Impact

The mixture proportion of recycled concrete was discussed by orthogonal design method. The influence of water-cement ratio, recycled aggregate quantity on workability, cube compressive strength of recycled concrete was analyzed. The experimental results indicated that，Recycled concrete mix proportion design should consider the impact of the water absorption of recycled aggregate. Unit water amount of recycled concrete should be plain concrete unit water consumption and recycled aggregate additional amount of water. Sand ratio should increase in the corresponding ordinary aggregate concrete sand ratio on the basis of 1 to 3 percent. When the water-cement ratio is 0.36 and construction waste content of 40% slag content of 20%, 28d compressive strength of concrete is 48.1MPa, slightly higher than the reference concrete (48.0MPa).

Study on the Impact of Polycarboxylic Acid Additive Experimental Process Parameters on Cement Adaptability

2015 ◽  
Vol 744-746 ◽  
pp. 1507-1513 ◽  
Author(s):  
Hai Chao Wang ◽  
Wei Wei Li ◽  
Fang Ning Sun ◽  
Zhi Gang Yang ◽  
Chen Chen ◽  
...  
Keyword(s):  
Process Parameters ◽  
Design Method ◽  
Orthogonal Design ◽  
Polymerization Process ◽  
Synthesis Process ◽  
Polycarboxylic Acid ◽  
Orthogonal Design Method ◽  
Experimental Process ◽  
Polymeric Acid ◽  
The Impact

By analyzing two Polycarboxylate cement admixture of different polymerization process adaptability, the cement paste experiment is carried out to show the influence of Polycarboxylate superplasticizer, slump agent and the cement synthesis process on cement adaptability. Through orthogonal design method, result is drawn from the comparison of the influence of initial liquidity and an hour liquidity under different conditions,which is base on treating Polymeric acid process parameters as effecting factor within a certain range. It is shown that the preferably optimized process parameters of Polycarboxylic acid exist in the same kind of cement.The system error caused by the impact of cement composition is indicated in different kinds of cement.The adaptability of Polycarboxylic acid cement admixture of the mother liquor is available in the process optimization of the parameters.

The Investigation of the Zirconium Silicate Coatings Prepared by APS

2011 ◽  
Vol 686 ◽  
pp. 678-685
Author(s):  
Yan Bo Liu ◽  
Quan Sheng Wang ◽  
Zhuang Ma ◽  
Zhong Du ◽  
Juan Liu
Keyword(s):  
Plasma Spraying ◽  
Design Method ◽  
Orthogonal Design ◽  
Functional Coatings ◽  
Zirconium Silicate ◽  
Spraying Parameters ◽  
Orthogonal Design Method ◽  
The Impact ◽  
Plasma Spraying Process ◽  
Spraying Process

The zirconium silicate can be deposited as functional coatings which will be used at high temperature because of its high melting point and low thermal conductivity. It can also prevent the oxygen of the environment through the coatings and react with the substrate. In this paper, plasma spraying technology was selected to prepare the coatings of zirconium silicate. The orthogonal design method was used to optimize the parameter of plasma spraying process. The content of zirconium silicate in the coatings was checked by XRD because of the decomposition of the zirconium silicate at 1711K.The bond strength and porosity of the coatings were also measured after the optimizing of the plasma spraying parameters in this paper. According the impact on the porosity, the factors of the process can be ordered as follows: spraying distance, current, primary gases and secondary gases. And the order of spraying factors according the impact on the content of zirconium silicate in the coatings was showed as follows: spraying distance, secondary gas, primary gas and current.

An Investigation of Hole Machining Process on a Carbon-Fiber Reinforced Plastic Sheet by Abrasive Waterjet

2016 ◽  
Vol 1136 ◽  
pp. 113-118 ◽  
Author(s):  
Kunlapat Thongkaew ◽  
Jun Wang ◽  
Guan Heng Yeoh
Keyword(s):  
Carbon Fiber ◽  
Process Parameters ◽  
Water Pressure ◽  
Traverse Speed ◽  
Hole Diameter ◽  
Abrasive Waterjet ◽  
Hole Size ◽  
Hole Quality ◽  
Hole Wall ◽  
Hole Machining

An experimental investigation of the hole machining performance for woven carbon-fiber reinforced PEEK (polyetheretherketone) sheets by an abrasive waterjet (AWJ) is presented. It is shown that AWJ machining can produce good quality holes if the cutting parameters are properly selected. Plausible trends of the hole quality with respect to the process parameters are discussed. Nozzle traverse speed and intended or programmed hole size are found to have a significant effect on the diameter error of the machined holes, hole roundness, and hole wall inclination angle, while water pressure and abrasive mass flow rate exhibit an insignificant effect. An increase in the traverse speed decreases the overall hole quality, while an increase in the programmed hole diameter decreases the hole diameter error and roundness error, but increases the hole wall inclination. There is not any clear trend of the hole wall surface roughness with respect to the process parameters. Moreover, high water pressures may result in hole defects, such as entrance surface chipping, delamination, internal cracking and fiber pull-out. It is found that the optimum process parameters are about 200 MPa water pressure, 2 mm/s nozzle traverse speed and 7.0 g/s abrasive mass flow rate. Recommendations are made for compensating for the hole size deviation and empirical models are fianlly developed for these hole characteristics.

IMPACT ASSESSMENT ON LEARNING MOTIVATION IN THE FRAMEWORK OF THE COMPETENCE APPROACH IN EDUCATION

2020 ◽  
Vol 22 (9) ◽  
pp. 28-34
Author(s):  
Huseynova А.А. ◽  
Vashchinnikova K.D.
Keyword(s):  
Design Method ◽  
Authentic Assessment ◽  
Educational Process ◽  
Learning Motivation ◽  
Assessment Process ◽  
Assessment Procedure ◽  
Positive Side ◽  
Educational Motivation ◽  
Educational Paradigm ◽  
The Impact

Turning to the new educational paradigm, the research paper considers the conditions for ensuring the effective-ness of authentic assessment of students ' achievements within the competence approach and the transition from traditional knowledge control to tests developed on the basis of the theory of pedagogical measurements. Special attention is paid to independent assessment as a tool for stimulating learning activities, as well as to the justifica-tion of the pattern design method used in the develop-ment of measurement tools. The experimental basis of the study is based on the results of an independent assess-ment of educational achievements of students of the sen-ior level of secondary vocational education in social studies in several educational organizations. As a result of the survey of participants in independent testing, the formation of a stable positive learning motivation is not-ed. The relationship with the assessment of the impact on educational motivation is confirmed by the respondents ' attitude to the authentic assessment procedure on the part of participants in the assessment process: school-children, teachers, and parents. As a result, it was re-vealed that all subjects of the educational process evalu-ate the impact of the proposed method of assessment on educational motivation from a positive side.

scholarly journals Erosion Transportation Processes as Influenced by Gully Land Consolidation Projects in Highly Managed Small Watersheds in the Loess Hilly–Gully Region, China

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1540
Author(s):  
Qianqian Ji ◽  
Zhe Gao ◽  
Xingyao Li ◽  
Jian’en Gao ◽  
Gen’guang Zhang ◽  
...  
Keyword(s):  
Similarity Theory ◽  
Design Method ◽  
Simulation Method ◽  
Practical Significance ◽  
Land Consolidation ◽  
Small Watershed ◽  
Flood Peak ◽  
Erosion Area ◽  
The Impact ◽  
Erosion Environment

The Loess Hilly–Gully region (LHGR) is the most serious soil erosion area in the world. For the small watershed with high management in this area, the scientific problem that has been paid attention to in recent years is the impact of the land consolidation project on the erosion environment in the gully region. In this study, the 3D simulation method of vegetation, eroded sediment and pollutant transport was innovated based on the principles of erosion sediment dynamics and similarity theory, and the impacts of GLCP were analyzed on the erosion environment at different scales. The verification results show that the design method and the scale conversion relationship (geometric scale: λl = 100) were reasonable and could simulate the transport process on the complex underlying surface of a small watershed. Compared with untreated watersheds, a significant change was the current flood peak lagging behind the sediment peak. There were two important critical values of GLCP impact on the erosion environment. The erosion transport in HMSW had no change when the proportion was less than 0.85%, and increased obviously when it was greater than 3.3%. The above results have important theoretical and practical significance for watershed simulation and land-use management in HMSW.

Trajectory shaping guidance law design using constraint-combining multiplier

2021 ◽  
pp. 095441002098637
Author(s):  
Min-Guk Seo ◽  
Chang-Hun Lee ◽  
Tae-Hun Kim
Keyword(s):  
Design Method ◽  
Impact Angle ◽  
State Variables ◽  
Flight Trajectory ◽  
Potential Significance ◽  
Guidance Law ◽  
Terminal Constraints ◽  
The Impact ◽  
Guidance Laws ◽  
Impact Angle Constraint

A new design method for trajectory shaping guidance laws with the impact angle constraint is proposed in this study. The basic idea is that the multiplier introduced to combine the equations for the terminal constraints is used to shape a flight trajectory as desired. To this end, the general form of impact angle control guidance (IACG) is first derived as a function of an arbitrary constraint-combining multiplier using the optimal control. We reveal that the constraint-combining multiplier satisfying the kinematics can be expressed as a function of state variables. From this result, the constraint-combining multiplier to achieve a desired trajectory can be obtained. Accordingly, when the desired trajectory is designed to satisfy the terminal constraints, the proposed method directly can provide a closed form of IACG laws that can achieve the desired trajectory. The potential significance of the proposed result is that various trajectory shaping IACG laws that can cope with various guidance goals can be readily determined compared to existing approaches. In this study, several examples are shown to validate the proposed method. The results also indicate that previous IACG laws belong to the subset of the proposed result. Finally, the characteristics of the proposed guidance laws are analyzed through numerical simulations.

scholarly journals Perceptions of midwives on shortage and retention of staff at a public hospital in Tshwane District

Curationis ◽  
2019 ◽  
Vol 42 (1) ◽  
Author(s):  
Mosehle S. Matlala ◽  
Thanyani G. Lumadi
Keyword(s):  
Decision Making ◽  
Design Method ◽  
Quality Care ◽  
Sampling Technique ◽  
The Status ◽  
Generic Qualitative ◽  
Tertiary Hospitals ◽  
Decision Making Processes ◽  
Group Interviews ◽  
The Impact

Background: Midwifery is the backbone of women and child healthcare. The shortage of staff in maternity units is a crisis faced by many countries worldwide, including South Africa.Objectives: This study aims to explore the perceptions of midwives on the shortage and retention of staff at a public institution.Method: The study was conducted at one of the tertiary hospitals in Tshwane District, Gauteng Province. A total of 11 midwives were interviewed through face-to-face and focus group interviews. An explorative, descriptive generic qualitative design method was followed, and a non-probability, purposive sampling technique was used. Thematic coding analysis was followed for analysing data.Results: The impact of shortage of midwives was reported to be directly related to poor provision of quality care as a result of increased workload, leading to low morale and burnout. The compromised autonomy of midwives in the high obstetrics dependency units devalues the status of midwives.Conclusion: Midwives are passionate about their job, despite the hurdles related to their day-to-day work environment. They are demoralised by chronic shortage of staff and feel overworked. Staff involvement in decision-making processes is a motivational factor for midwives to stay in the profession. The midwives need to be in the centre of the decision-making processes related to their profession. The revision of the scope of practice and classification of midwifery profession away from general nursing complex by the South African Nursing Council (SANC) could place midwifery in its rightful status.

Numerical Simulation and Experimental Study on Water Mist Fire Suppression for Cooking Fog Discharge Pipe

2014 ◽  
Vol 915-916 ◽  
pp. 356-361
Author(s):  
Zheng Wen Xie
Keyword(s):  
Design Method ◽  
Fire Suppression ◽  
Orthogonal Design ◽  
Water Mist ◽  
Simulation Software ◽  
Droplet Radius ◽  
Test Analysis ◽  
Injection Angle ◽  
Fire Extinguishing ◽  
Flow Quantity

FDS simulation software was used to establish the full size lampblack physics model of single wind pipe, using the orthogonal design method design of analog calculation conditions, research in the nozzle pressure, the droplet radius, nozzle, flow quantity and injection angle parameters under different conditions of water mist fire extinguishing effect. Based on a full-scale combustion and water mist fire extinguishing experiment, the water mist fire suppression was observed and test analysis etc, to better understand the flue water mist fire extinguishing feasibility, provides the theory basis for the design of efficient, reliable flue fire extinguishing system.

The Study on Solid Superacid Synthesis of K12A with Manufacturing Equipment

2012 ◽  
Vol 583 ◽  
pp. 285-288
Author(s):  
Dong Mei Zhao ◽  
Xue Peng Liu
Keyword(s):  
Catalytic Activity ◽  
Metal Oxide ◽  
Design Method ◽  
Orthogonal Design ◽  
Manufacturing Equipment ◽  
Solid Superacid ◽  
Orthogonal Design Method ◽  
Superacid Catalyst ◽  
Calcined Temperature ◽  
Very High

By orthogonal design method, Catalytic activity of /ZrO2 solid superacid is studied, and the influence of catalyst characteristic and structure by manufacturing equipment is issued. It is concluded that the best prepared conditions of the superacid catalyst /ZrO2 for the synthesis of Octyl-Polyglycoside are followed:(1) PH=9.5; (2) calcined temperature at 500; (3) M(H2SO4)=0.5mol/L. Using this kind of catalyst the conversion of glueoside may reach as high as 96% in the synthesis of OCtyl-Polyglycoside and the selectivity is very high for the synthesis of Octyl-Polyglycoside. By introducing other metal oxide, the catalytic activity of complex solid superacid is studied.

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