scholarly journals AN EXPERIMENTAL STUDY FOR QUALITY ASSURANCE OF FREE-FORM CONCRETE PANELS PRODUCED BY CNC MACHINE

2018 ◽  
Vol 24 (2) ◽  
pp. 145-154 ◽  
Author(s):  
Jeeyoung LIM ◽  
Do Yeong KIM ◽  
Sunkuk KIM
Keyword(s):  
Experimental Study ◽  
Quality Assurance ◽  
Labor Cost ◽  
Free Form ◽  
Shape Error ◽  
Cnc Machine ◽  
Concrete Panels ◽  
Short Time ◽  
Change Material

Various studies have been conducted to construct free-form buildings, but it still takes a lot of labor, cost, and time to assure the accuracy of designed shapes. In particular, molds for the production of free-form concrete panels (FCPs) are putting enormous burdens on productivity and cost. To produce FCPs economically, a computerized numeric control (CNC) machine that produces phase change material (PCM) molds for persistent use was developed in this study. The technology using CNC machine can produce precisely free-form molds and panels in a short time compared to the manual method. However, in order to commercialize this technology, it is necessary to verify the shape error of the FCPs. Therefore, the purpose of this paper is an experimental study for securing FCP quality produced by a CNC machine. The results of this study will be used to mass-produce uniform quality of FCPs without depending on the skill and workmanship of the labo.

The Experimental Study of Ultrasonic Testing Prestressed Bellows Pore Grouting Quality

2014 ◽  
Vol 711 ◽  
pp. 461-468 ◽  
Author(s):  
Shao Lin Zhou ◽  
Feng Zhang ◽  
Yuan Cao
Keyword(s):  
Experimental Study ◽  
Ultrasonic Testing ◽  
Concrete Slab ◽  
Ultrasonic Method ◽  
Test Results ◽  
Concrete Panels ◽  
Head Waves ◽  
Different Thickness ◽  
Regular Patterns

The ultrasonic method can be used for testing and analyzing the pore size of concrete. By studying the spectrum curves which is formed by ultrasonic transmitting at different thickness concrete panels can we get different time regular patterns of head waves formed by ultrasonic going through homogeneous concrete, compact grouting pore, grouting incompact pore, not grouting pore. All these provide a basis for predicting prestressed bellows pore grouting quality and judging whether there is interspace in pore. By artificially setting defects in bellows pore, for example, filling the pore to completely empty, 1/4 compact, 1/2 compact, 3/4 compact, fully compact and then embedding them in a concrete slab for ultrasonic testing. Test results show that the ultrasonic method can effectively evaluate the grouting quality of prestressed bellows pore.

scholarly journals A SOLUTION OF SUBORDINATE VERTICES FOR QUALITY CONNECTIONS OF EXTERNAL FREE-FORM CONCRETE PANELS

2018 ◽  
Vol 24 (5) ◽  
pp. 399-409
Author(s):  
Jeeyoung Lim ◽  
Seunghyun Son ◽  
Do Yeong Kim ◽  
Heni Fitriani ◽  
Sunkuk Kim
Keyword(s):  
Reinforced Concrete ◽  
Glass Fiber ◽  
Fiber Reinforced Concrete ◽  
Junction Point ◽  
Free Form ◽  
Fiber Reinforced ◽  
Aesthetic Quality ◽  
Concrete Panels ◽  
Glass Fiber Reinforced

3D-designs of free-form buildings are developed using a computer due to difficulty of shape implementation. When producing free-form concrete panel (FCP) using materials such as GFRC (glass fiber reinforced concrete), engineers or manufacturers should precisely calculate the offset value or geometry of each member at the junction point of three or more FCPs before it is constructed. However, it is difficult to calculate offset geometry easily and quickly, and no research has been conducted on this topic. Therefore, the objective of this paper is to develop a solution of subordinate vertices for quality connections of external free-form concrete panels. The developed mathematical solutions practically support the production of FCPs with precise installation to ensure aesthetic quality of the building. This paper academically contributes to the automatic creation of joint details of FCPs implemented by BIM.

scholarly journals Mexico's Approach to Quality Assurance

1998 ◽  
Author(s):  
Mohammed El-Khawas ◽  
Elaine El-Khawas
Keyword(s):  
Higher Education ◽  
Quality Assurance ◽  
Public Expenditures ◽  
Faculty Salaries ◽  
Quality Of Higher Education ◽  
Higher Education Quality ◽  
Additional Funding ◽  
The Government ◽  
Short Time

The last decade has seen substantial growth throughout the world in higher education quality assurance systems. As one knowledgeable observer notes, more than 50 agencies now exist worldwide that have roles related to quality assessment or quality assurance.1 In most cases, these agencies have been mandated by government decrees and follow a design developed by ministry officials. Often these agencies have encountered resistance or criticism. In other instances, their approach has had to be revised extensively— or even disbanded—after a short time. By the late 1980s, Mexican institutions of higher education were in dire need of additional funding. The financial crisis of the 1980s caused a 50 percent decline in the purchasing power of faculty salaries, forcing many qualified academics to quit their jobs or to take on additional employment. This resulted in severe staffing problems and a deterioration in teaching conditions at a time of increasing enrollments. This led to public concern and government demands for improving the quality of higher education. With the economic recovery in the late 1980s, the government was ready to increase public expenditures on higher education but insisted on reforms and increased public accountability.

scholarly journals AN EXPERIMENTAL STUDY ON THE DEFROSTING PERFORMANCE OF A PCM-BASED REVERSE-CYCLE DEFROSTING METHOD FOR AIR SOURCE HEAT PUMPS

2010 ◽  
Vol 18 (04) ◽  
pp. 327-337 ◽  
Author(s):  
MINGLU QU ◽  
SHIMING DENG ◽  
YIQIANG JIANG
Keyword(s):  
Experimental Study ◽  
Fundamental Problem ◽  
Heat Pumps ◽  
Operating Conditions ◽  
Space Heating ◽  
Normal Space ◽  
Indoor Thermal Comfort ◽  
Heating Mode ◽  
Change Material

When an ASHP unit operates in heating mode, frost can be accumulated on the surface of its outdoor coil. Currently the most widely used defrosting method for ASHPs is reverse cycle defrost. However, the fundamental problem for such a method is that there is insufficient heat available for ASHPs during defrosting. This paper reports on an experimental study of developing a novel reverse-defrosting method which was thermal energy storage (TES) based on using phase change material (PCM). Comparative experiments were carried out at two operating conditions: standard defrosting condition and the PCM-based defrosting condition. Results indicated that the use of this PCM-based reverse defrosting method could help shorten defrosting time, increase defrost COP d, enhance system reliability, reduce transition duration from defrost to normal space heating operation, and improve indoor thermal comfort for occupants during defrosting and heating resumption process while without degrading the quality of space heating provided by the ASHP during heat operation.

scholarly journals Energy and CO2 Reduction of Aluminum Powder Molds for Producing Free-Form Concrete Panels

2020 ◽  
Vol 12 (22) ◽  
pp. 9613
Author(s):  
Donghoon Lee ◽  
Sunkuk Kim
Keyword(s):  
Co2 Emissions ◽  
Aluminum Powder ◽  
Energy Use ◽  
Phase Change Materials ◽  
Co2 Reduction ◽  
Free Form ◽  
Cnc Machine ◽  
Repeated Heating ◽  
Concrete Panels ◽  
Reduction Effect

Free-form design may enhance the architectural value of buildings in terms of aesthetic and symbolic effects. However, it is difficult to reuse the mold of free-form concrete segments, so they are manufactured for single use. Manufacturing these molds is a time-consuming process that requires a lot of manpower. To solve these problems, there have been numerous studies on the use of phase change materials (PCMs) to make the molds. PCM molds represent a new technique of producing free-form panels using a computerized numeric control (CNC) machine that employs low-cost material to produce free-form concrete panels. However, PCM molds require a substantial amount of time and energy during fabrication because repeated heating and cooling cycles are required during panel production, and this process increases the CO2 emissions. Thus, the purposes of this study were to develop composite molds using aluminum powder to improve PCM mold performance and to conduct experiments to quantify the reduction of energy use and CO2 emissions. As a result of cooling experiments, it was found that the aluminum powder mold had an energy reduction effect of 14.3% against the PCM mold that had been produced only with paraffin wax, and CO2 reduction effect of more than 50% against the conventional mold.

scholarly journals Development of Sustainable Production Technology of Free-Form Concrete Panels Using a Multi-Point Press CNC Machine

2021 ◽  
Vol 13 (4) ◽  
pp. 1990
Author(s):  
Sunkuk Kim ◽  
Seunghyun Son ◽  
Donghoon Lee
Keyword(s):  
Production Technology ◽  
Technological Development ◽  
Free Form ◽  
Cnc Machine ◽  
Silicon Plate ◽  
Shape Accuracy ◽  
Concrete Panels ◽  
Short Period ◽  
The Mean ◽  
Concrete Materials

Maintaining shape accuracy in the production of concrete panels of free-form buildings is time-consuming and costly. In addition, disposable molds used for free-form panels are not sustainable. Such problems can be solved by developing a suitable computerized numeric control (CNC) machine that can produce an accurately shaped reusable form for free-form concrete materials in a short period of time. This project develops a production technology of quality free-form concrete panels using a CNC machine and verifies the shape quality through an experiment. We designed a multi-point press CNC machine and verified its quality. The CNC machine implements a smooth free-form shape by changing the shape of the silicon plate by movement of the rods. The silicone plate for the CNC machine generates a slight error due to the elastic cover and mechanical clearance. The mean error rate was within 3%, based on the thickness of the panels, at the 95% confidence level. Verification of these errors will provide meaningful information to a similar type of machine development. In addition, the project results will be helpful in technological development for the production of free-form concrete panels of uniform quality, whose shape accuracy is not influenced by the skills and competence of the workers producing the panels.

ANALISIS VISUAL PADA SAMPUL DEPAN MAJALAH DESAIN GRAFIS “CONCEPT” EDISI ULTAH PERDANA (Sebuah Kajian Semiotika)

DeKaVe ◽  
2013 ◽  
Vol 1 (2) ◽  
Author(s):  
Prayanto WH
Keyword(s):  
Graphic Design ◽  
Roland Barthes ◽  
Specific Design ◽  
Design Work ◽  
Design Elements ◽  
Semiotic Approach ◽  
Short Time ◽  
Content Information ◽  
Magazine Cover

Magazine is one of the forms of mass media that has fungsikomunikasi to convey information to mass audiences. The cover is an important element because it is through cover / cover one can guess the contents of the magazine, as well as further interested to know further information contained therein. On a magazine cover consists of drawings and writings are arranged in such a way that looks interesting and has meaning Press publications, especially magazines, today's not enough just to rely on the quality of news or manuscript, although verbal aspect is very important. It must be recognized that the visual aspects (design) as the cover / envelope has crucial role to capture the prospective reader. For the cover of a magazine is a window that shows the content information, can be either a text or photographs, illustrations, and design elements. The function of a magazine cover is to attract, dazzle prospective readers, by way influence the thoughts flow in a short time. So it's no wonder much current the magazine publisher who made the cover of such a way as to attract the attention of prospective readers. Thus the task of designers to magazine cover to create designs that attract the attention of the reader becomes increasingly severe. This study tries to analyze a visual on the front cover Magazine Graphic Design 'Concept' birthday inaugural edition by using the Roland Barthes' semiotic approach. As Roland Barthes (1984), any simple "design work (magazine cover)" continue to play in management of the sign. So that will generate a message (image) specific. Design cover, usually contains the elements of the sign in the form of objects, context of the environment, people or other beings who provide meaning to objects, and text (of writing) that reinforce the meaning.Keyword: cover, magazine Concept, semiotics

CONCEPTUAL BASES OF ADAPTATION OF UKRAINE’S HIGHER EDUCATION TO THE STANDARDS OF EDUCATION QUALITY OF THE EUROPEAN AREA

2018 ◽  
Author(s):  
Nina Batechko
Keyword(s):  
Higher Education ◽  
Quality Assurance ◽  
European Higher Education Area ◽  
Quality Of Higher Education ◽  
European Area ◽  
European Higher Education ◽  
European Standards ◽  
Conceptual Foundations

The article outlines the conceptual framework for adapting Ukrainian higher education to the Standards and Recommendations for Quality Assurance in the European higher education area. The role of the Bologna Declaration in ensuring the quality of higher education in Europe has been explained. The conceptual foundations and the essence of standards and recommendations on quality assurance in the European higher education area have been defined. The Ukrainian realities of the adaptation of higher education of Ukraine to the educational European standards of quality have been characterized.

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