Recovery of Metal Concentrates from Waste Printed Circuit Boards by Pyrolysis and Mechanical Separation

( Kurniawan Kurniawan ),( Sookyung Kim ),( Jae-chun Lee ) 한국폐기물자원순환학회 2022 ISSE 초록집 Vol.2022 No.-

Waste printed circuit boards (WPCBs) are considered a fairly good quality secondary resource for various critical/strategic, and high-value metals, including precious metals (Au, Ag, Pt, Pd), rare and rare earth metals (Sc, Y, La, Ce), base metals (Cu, Ni, Sn, Pb, Al), etc. Therefore, recovering these metals from WPCBs can be a part of efforts to ensure their sustainable supply in the future. However, the recovery process faces challenges due to the presence of organic substrates chelated to the metals. This study proposed pyrolysis and mechanical-physical separation to recover the valuable metals from WPCBs. Firstly the WPCBs were treated by pyrolysis to not only decompose the organic, but also ease the separation of organic substrates with that of metal sheets. The results of metal analysis showed no loss of metals during the pyrolysis step, which is important for the recovery process. The suitable pyrolysis parameters considered were 500 °C temperature, 20 °C/min heating rate, 0.3 L/min N2 flow rate, and 10 min holding time. The solid char products so obtained were subjected to mechanical process particularly the sieving at three different sizes (+4.75 mm, +0.5 mm, and -0.5 mm). Most of the metals were concentrated and present in +4.75 and +0.5 mm samples, and consequently, they were recovered by the magnetic- and electrostatic separation processes. In the case of the -0.5 mm sample, the metals were separated by a simple float-sink method. This study contributed to efficiently recycle the valuable metals by applying a suitable hydrometallurgical process from the concentrated fractions generated as above while treating the WPCBs.

Current status of the recycling of e-waste in Indonesia

Kurniawan Kurniawan,Soefihara Muhammad Dzikri Ahira,Nababan Deddy Chandra,Kim Sookyung 한국자원공학회 2022 Geosystem engineering Vol.25 No.3

Electronic waste (e-waste) has become a major economic and environmental concern. It requires the development of sustainable and integrated recycling systems capable of recovering valuable constituents while simultaneously protecting the environment. While many developed countries have established such recycling systems, most developing countries, including Indonesia, lack such systems and have a low level of public awareness about e-waste. This article focuses on the current state of e-waste recycling in Indonesia. The estimated amount of e-waste generation and distribution in the country, potential economic recovery, relevant legal frameworks, and recycling practices are presented. The review also highlights barriers to formal e-waste management and recycling in Indonesia, such as (i) superiority of the informal sector, (ii) lack of regulation and infrastructure, (iii) lack of awareness and reliable data about e-waste, (iv) low rate of research works on recycling technology development, and (v) large diversity of socio-economic and geographic conditions in Indonesia. The study suggests strategies for establishing a sustainable e-waste recycling system in Indonesia, including potential processing routes and scenarios that integrate the actors involved in e-waste collection, pretreatment, and metal extraction.

Smart City Feature Using Six European Framework and Multi Expert Multi Criteria: A Sampling of the Development Country

Kurniawan, Fachrul,Haviluddin, Haviluddin,Collantes, Leonel Hernandez,Nugroho, Supeno Mardi Susiki,Hariadi, Mochamad International Journal of Computer ScienceNetwork S 2022 International journal of computer science and netw Vol.22 No.7

Continuous development is the key of development issue in developing nations. Smart city measurement is prevalently carried through in the cities in which the nations have been classified as industrialized countries. In addition, cities in Europe becomes the models of smart city system. Smart city concept used in the cities in Europe applies six predominant features i.e. smart economic, smart mobility, smart environment, smart people, smart living, and smart governance. This paper focuses on figuring out city' development strategy in developing nations particularly Indonesia in regard with European Framework by way of Multi Expert Multi Criterion Decision Making (ME-MCDM). Recommendation is resulted from the tests using the data collected from one of the metropolis cities in Indonesia, whereby issuing recommendation must firstly implement smart education, secondly communication, thirdly smart government, and fourthly smart health, as well as simultaneously implement smart energy and smart mobility.

Optimization of forensic identification through 3-dimensional imaging analysis of labial tooth surface using open-source software

Kurniawan Arofi,Alias Aspalilah,Yusof Mohd Yusmiaidil Putera Mohd,Marya Anand 대한영상치의학회 2024 Imaging Science in Dentistry Vol.54 No.1

Purpose: The objective of this study was to determine the minimum number of teeth in the anterior dental arch that would yield accurate results for individual identification in forensic contexts. Materials and Methods: The study involved the analysis of 28 sets of 3-dimensional (3D) point cloud data, focused on the labial surface of the anterior teeth. These datasets were superimposed within each group in both genuine and imposter pairs. Group A incorporated data from the right to the left central incisor, group B from the right to the left lateral incisor, and group C from the right to the left canine. A comprehensive analysis was conducted, including the evaluation of root mean square error (RMSE) values and the distances resulting from the superimposition of dental arch segments. All analyses were conducted using CloudCompare version 2.12.4 (Telecom ParisTech and R&D, Kyiv, Ukraine). Results: The distances between genuine pairs in groups A, B, and C displayed an average range of 0.153 to 0.184 mm. In contrast, distances for imposter pairs ranged from 0.338 to 0.522 mm. RMSE values for genuine pairs showed an average range of 0.166 to 0.177, whereas those for imposter pairs ranged from 0.424 to 0.638. A statistically significant difference was observed between the distances of genuine and imposter pairs (P<0.05). Conclusion: The exceptional performance observed for the labial surfaces of anterior teeth underscores their potential as a dependable criterion for accurate 3D dental identification. This was achieved by assessing a minimum of 4 teeth.

Surface roughness of two-frequency elliptical vibration texturing (TFEVT) method for micro-dimple pattern process

Kurniawan, R.,Kiswanto, G.,Ko, T.J. Pergamon ; Elsevier Science Ltd 2017 International journal of machine tools & manufactu Vol.116 No.-

<P>This study presents a two-frequency elliptical vibration texturing (TFEVT) method that adds elliptical vibration cutting (EVC) to a conventional texturing (CT) method. The TFEVT method improves the surface' roughness compared to the CT method during a micro-dimple texturing process. Kinematic analysis and a theoretical surface roughness model are presented based on the effect of the tool edge radius. The effect of this radius cannot be neglected since it is nearly equal to the undeformed chip thickness at the micro scale. The replication of the tool edge radius profile, the effect of the material spring back, and the residual error were also considered in the surface roughness model. The surface roughness of a micro-dimple also includes the replication of the tool edge radius profile, which can be determined by using a replication technique. The deflection of material spring back is formulated according to the value of the minimum principal stress in the tertiary deformation zone between the flank face and the machined surface, and the plastic strain value is determined based on elasto-plastic deformation theory. Experimental and simulation results were compared to validate the surface roughness model.</P>

Joint Demosaicing and Super-resolution of Color Filter Array Image based on Deep Image Prior Network

Kurniawan, Edwin,Lee, Suk-Ho The Institute of Internet 2022 International journal of advanced smart convergenc Vol.11 No.2

In this paper, we propose a learning based joint demosaicing and super-resolution framework which uses only the mosaiced color filter array(CFA) image as the input. As the proposed method works only on the mosaicied CFA image itself, there is no need for a large dataset. Based on our framework, we proposed two different structures, where the first structure uses one deep image prior network, while the second uses two. Experimental results show that even though we use only the CFA image as the training image, the proposed method can result in better visual quality than other bilinear interpolation combined demosaicing methods, and therefore, opens up a new research area for joint demosaicing and super-resolution on raw images.

Atmospheric pressure glow discharge plasma polymerization for surface treatment on sized basalt fiber/polylactic acid composites

Kurniawan, Denni,Kim, Byung Sun,Lee, Ho Yong,Lim, Joong Yeon Elsevier 2012 Composites Part B, Engineering Vol.43 No.3

<P><B>Abstract</B></P> <P>This study evaluates the effects of atmospheric pressure glow discharge plasma polymerization on basalt fiber to the properties of basalt fiber/polylactic acid composite. Plasma exposure time was the object of interest so the basalt fiber was exposed to the glow for 0.5, 1.5, 3, 4.5, and 6min, respectively. Characterization was conducted on the plasma polymerized fibers by identifying the molecular bonds and surface morphology. Properties (mechanical and thermal) and water absorption behavior of the fabricated composites were tested. Plasma exposure time on BF affected mechanical properties of its BF/PLA composite, showing a decline in mechanical properties until the BF was plasma polymerized beyond 1.5min. Optimum plasma polymerization on BF was for 4.5min of plasma exposure time where the composite’s strength and modulus were 45% and 18% higher, respectively, compared to those of untreated one.</P>

Measurement of burr removal rate and analysis of machining parameters in ultrasonic assisted dry EDM (US-EDM) for deburring drilled holes in CFRP composite

Kurniawan, Rendi,Thirumalai Kumaran, S.,Arumuga Prabu, V.,Zhen, Yu,Park, Ki Moon,Kwak, Ye In,Mofizul Islam, Md.,Ko, Tae Jo Elsevier 2017 MEASUREMENT -LONDON- Vol.110 No.-

<P><B>Abstract</B></P> <P>An ultrasonic assisted dry electrical discharge machining (US-EDM) process in a gaseous fluid medium was proposed to remove the burrs formed on the exit region of a drilled hole. In preliminary experiment, three different electrode tools (copper, brass, and aluminum) were utilized. In secondary experiment, US-EDM and dry-EDM were compared and performed using the copper tool. US-EDM parameters, such as capacitance (C), pulse-on time (T<SUB>ON</SUB>), and vibration amplitude (A<SUB>p-p</SUB>) were considered as functions of the predicted burr removal rates (BRRs) model. Based on signal to noise (S/N) ratio analysis, machining parameters C=10<SUP>−2</SUP> µF, T<SUB>ON</SUB> =150µs, and A<SUB>p-p</SUB> =4.919µm provided the optimal BRR. The BRR was affected the most by capacitance, followed by pulse-on time and ultrasonic vibration amplitude. The copper tool provided a higher BRR than other tools. US-EDM is considerably effective when T<SUB>ON</SUB> is low and the performance of US-EDM is better than that of Dry-EDM. Scanning electron microscopy (SEM) analysis showed that the US-EDM method created a heat-affected zone surrounding the machined surface of the deburred exit hole in range of 200µm–500µm.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The novelty of a burr removal rate (BRR) model was proposed and validated in this study. </LI> <LI> The influence of the US-EDM process parameters on the BRR value was studied. </LI> <LI> The relationship between the input and output processes was evaluated statistically. </LI> <LI> The optimal machining parameter for the BRR value was validated. </LI> <LI> The comparison between US-EDM and Dry-EDM process was evaluated. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Micromagnetic investigation of the sub-nanosecond magnetic pulse driven domain wall motion in CoFeB nanowire

Kurniawan Candra,Djuhana Dede,Soegijono Bambang,Kim Dong-Hyun 한국물리학회 2021 Current Applied Physics Vol.27 No.-

We report our micromagnetic simulations based on Landau-Lifshitz-Gilbert (LLG) equation for CoFeB nanowire which was exposed by sub-nanosecond magnetic pulse with varied pulse width between 100 and 1000 ps. It is found that the Walker Breakdown field (HWB) shifted as the field pulse duration decreased and reached at the highest value in case of 100 ps pulse width, then decreased steeply with respect to the pulse width up to 400 ps. HWB values are not significantly dependent for pulses longer than 500 ps. It is observed that, below the HWB, the exchange energy is larger than the demagnetization energy in the wider nanowire. By energy density analysis, it is understood that the increase of HWB values in the cases of narrower pulse width was to compensate the energy needed to move the DW.

Experimental and analytical study of ultrasonic elliptical vibration cutting on AISI 1045 for sustainable machining of round-shaped microgroove pattern

Kurniawan, Rendi,Kumaran, S. Thirumalai,Ali, Saood,Nurcahyaningsih, Dwi Ayu,Kiswanto, Gandjar,Ko, Tae Jo Springer-Verlag 2018 INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TE Vol.98 No.5