Self-Relaxant Superelastic Matrix Derived from C₆₀ Incorporated Sn Nanoparticles for Ultra-High-Performance Li-Ion Batteries

Ardhi, Ryanda Enggar Anugrah,Liu, Guicheng,Tran, Minh Xuan,Hudaya, Chairul,Kim, Ji Young,Yu, Hyunjin,Lee, Joong Kee American Chemical Society 2018 ACS NANO Vol.12 No.6

<P>Homogeneously dispersed Sn nanoparticles approximately ⩽10 nm in a polymerized C<SUB>60</SUB> (PC<SUB>60</SUB>) matrix, employed as the anode of a Li-ion battery, are prepared using plasma-assisted thermal evaporation coupled by chemical vapor deposition. The self-relaxant superelastic characteristics of the PC<SUB>60</SUB> possess the ability to absorb the stress-strain generated by the Sn nanoparticles and can thus alleviate the problem of their extreme volume changes. Meanwhile, well-dispersed dot-like Sn nanoparticles, which are surrounded by a thin SnO<SUB>2</SUB> layer, have suitable interparticle spacing and multilayer structures for alleviating the aggregation of Sn nanoparticles during repeated cycles. The Ohmic characteristic and the built-in electric field formed in the interparticle junction play important roles in enhancing the diffusion and transport rate of Li ions. SPC-50, a Sn-PC<SUB>60</SUB> anode consisting of 50 wt % Sn and 50 wt % PC<SUB>60</SUB>, as confirmed by energy-dispersive X-ray spectroscopy analysis, exhibited the highest electrochemical performance. The resulting SPC-50 anode, in a half-cell configuration, exhibited an excellent capacity retention of 97.18%, even after 5000 cycles at a current density of 1000 mA g<SUP>-1</SUP> with a discharge capacity of 834.25 mAh g<SUP>-1</SUP>. In addition, the rate-capability performance of this SPC-50 half-cell exhibited a discharge capacity of 544.33 mAh g<SUP>-1</SUP> at a high current density of 10 000 mA g<SUP>-1</SUP>, even after the current density was increased 100-fold. Moreover, a very high discharge capacity of 1040.09 mAh g<SUP>-1</SUP> was achieved with a capacity retention of 98.67% after 50 cycles at a current density of 100 mA g<SUP>-1</SUP>. Futhermore, a SPC-50 full-cell containing the LiCoO<SUB>2</SUB> cathode exhibited a discharge capacity of 801.04 mAh g<SUP>-1</SUP> and an areal capacity of 1.57 mAh cm<SUP>-2</SUP> with a capacity retention of 95.27% after 350 cycles at a current density of 1000 mA g<SUP>-1</SUP>.</P> [FIG OMISSION]</BR>

Modified ZnO Electron Transport Layers for Depleted Heterojunction Quantum Dot Solar Cells

Ryanda Enggar Anugrah Ardhi,Havid Aqoma,장성연 한국고분자학회 2015 한국고분자학회 학술대회 연구논문 초록집 Vol.2015 No.4

Pseudocapacitive Characteristics of Low-Carbon Silicon Oxycarbide for Lithium-Ion Capacitors

Halim, Martin,Liu, Guicheng,Ardhi, Ryanda Enggar Anugrah,Hudaya, Chairul,Wijaya, Ongky,Lee, Sang-Hyup,Kim, A-Young,Lee, Joong Kee American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.24

<P>Lithium-ion capacitors (LICs) and lithium-ion batteries (LIBs) are important energy storage devices. As a material with good mechanical, thermal, and chemical properties, low-carbon silicon oxycarbide (LC-SiOC), a kind of silicone oil-derived SiOC, is of interest as an anode material, and we have examined the electrochemical behavior of LC-SiOC in LIB and LIC devices. We found that the lithium storage mechanism in LC-SiOC, prepared by pyrolysis of phenyl-rich silicon oil, depends on an oxygen-driven rather than a carbon-driven mechanism within our experimental scope. An investigation of the electrochemical performance of LC-SiOC in half- and full-cell LIBs revealed that LC-SiOC might not be suitable for full-cell LIBs because it has a lower capacity (238 mAh g(-1)) than that of graphite (290 mAh g(-1)) in a cutoff voltage range of 0-1 V versus Li/Li+, as well as a substantial irreversible capacity. Surprisingly, LC-SiOC acts as a pseudocapacitive material when it is tested in a half-cell configuration within a narrow cutoff voltage range of 0-1 V versus Li/Li+. Further investigation of a 'hybrid' supercapacitor, also known as an LIC, in which LC-SiOC is coupled with an activated carbon electrode, demonstrated that a power density of 156 000 W kg(-1) could be achieved while maintaining an energy density of 25 Wh kg(-1). In addition, the resulting capacitor had an excellent cycle life, holding similar to 90% of its energy density even after 75 000 cycles. Thus, LC-SiOC is a promising active material for LICs in applications such as heavy-duty electric vehicles.</P>

Association Preoperative Protein Adequacy and Post Elective Laparotomy Surgical Site Infection

Davie Muhamad,Nurul Ratna Mutu Manikam,Ridho Ardhi Syaiful 대한소화기학회 2023 대한소화기학회지 Vol.82 No.6

Background/Aims: Postoperative complications tend to occur in high-risk populations, including those undergoing major surgery. Surgical site infections (SSI) are some of the most common postoperative complications in laparotomy procedures. Surgery induces a postoperative stress response, triggering an inflammatory process that increases muscle protein proteolysis. Preoperative protein intake increases muscle protein reserves and supports postoperative wound healing and immunity. This study analyzed the association between preoperative protein adequacy and post-elective laparotomy SSI. Methods: A prospective cohort study was conducted on 93 subjects with an adequate protein group of 48 subjects and an inadequate protein group of 45 subjects undergoing elective laparotomy at Dr. Cipto Mangunkusumo Hospital, Jakarta. The protein adequacy was analyzed using an interview method for seven days preoperatively. Patient monitoring was carried out for 30 days postoperatively to assess the complications in the form of SSIs. The association between protein adequacy and SSI was analyzed using a Chi-Square test, and multivariate analysis was performed to assess the factors most associated with post-elective laparotomy SSI. Results: An association was observed between preoperative protein adequacy and post-elective laparotomy SSI (RR 3.413; 95% CI, 1.363–8.549; p=0.004). Multivariate analysis showed that the preoperative protein adequacy and preoperative albumin levels were strongly predictive of the occurrence of SSI. Conclusions: The preoperative protein adequacy and albumin levels were strongly related to predicting the post-elective laparotomy SSI.

Hierarchically structured photoanode with enhanced charge collection and light harvesting abilities for fiber-shaped dye-sensitized solar cells

Liu, Guicheng,Wang, Manxiang,Wang, Hui,Ardhi, Ryanda Enggar Anugrah,Yu, Hyunjin,Zou, Dechun,Lee, Joong Kee Elsevier 2018 Nano energy Vol.49 No.-

<P><B>Abstract</B></P> <P>The performances of fiber dye-sensitized solar cells (FDSSCs), in terms of charge collection efficiency, light-harvesting ability, and structural stability, are improved through a novel hierarchically structured photoanode based on a Ti microridge/nanorod-modified wire substrate. The microridge made of several Ti micropits is inserted into TiO<SUB>2</SUB> layer to shorten the photoelectron transport distance from the original place in the TiO<SUB>2</SUB> layer to substrate and to increase the electron transport rate. The Ti micropits are used as light-gathering centers to collect the reflected light. Meanwhile, the Ti nanorods are evenly distributed on the surface of the microridge-coated Ti wire substrate, which increases the contact area between the substrate and the TiO<SUB>2</SUB> layer in order to suppress the electron recombination and scatters the incident light to further improve the light-harvesting ability. Therefore, the charge collection and power conversion efficiencies of the novel FDSSC have been accordingly enhanced by 17.7% and 61.6%, respectively, compared with traditional FDSSC. Moreover, the structural stability of the novel FDSSC has been strengthened.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hierarchically structured photoanode substrate is a Ti microridge/nanorod-modified wire. </LI> <LI> Novel design enhances charge collection and light-harvesting abilities, concurrently. </LI> <LI> Novel FDSSC exhibits the highest PCE of 8.128% in the field of nanocrystalline-based FDSSCs so far. </LI> <LI> Ti microridges shorten photoelectron transport distance and are used as light-gathering centers. </LI> <LI> Ti nanorods suppress electron recombination and scatters the incident light. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The performances such as charge collection efficiency, light-harvesting ability and structural stability of fiber dye-sensitized solar cells (FDSSCs) are improved through a novel hierarchically structured photoanode based on a Ti microridge/nanorod-modified wire-substrate.</P> <P>[DISPLAY OMISSION]</P>

Study on a stretchable, fiber-shaped, and TiO₂ nanowire array-based dye-sensitized solar cell with electrochemical impedance spectroscopy method

Liu, Guicheng,Wang, Hui,Wang, Manxiang,Liu, Wenbing,Anugrah Ardhi, Ryanda Enggar,Zou, Dechun,Lee, Joong Kee Elsevier 2018 ELECTROCHIMICA ACTA Vol.267 No.-

<P><B>Abstract</B></P> <P>A spring-like Ti@TiO<SUB>2</SUB> nanowire array wire has been introduced into a stretchable fiber-shaped dye-sensitized solar cell (FDSSC) as a photoanode to achieve high flexibility and elasticity in this paper. Given the TiO<SUB>2</SUB> layer, which was prepared by a hydrothermal reaction in the optimized NaOH concentration of 2.5 mol L<SUP>−1</SUP>, with a 1D structure and high adhesion between the TiO<SUB>2</SUB> nanowire array and the Ti wire substrate, the novel FDSSC still possesses photoelectric conversion efficiency retention rates of approximately 97.00% and 95.95% after bending to a radius of 1.0 cm and stretching to 100% strain, respectively. EIS result shows the degradation mechanism of the FDSSC photoelectric performance: the bending test leads to more terrible electron combination; the stretching operation increases the internal resistance and charge-transfer resistance at the counter electrode. Moreover, it's worth noting that, this is the first time to show a 100%-stretching degree in the FDSSC research field so far.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A fiber-shaped, stretchable, TiO<SUB>2</SUB> nanowire array-based DSSC was reported firstly. </LI> <LI> Using EIS analysis method to analyse effect of bending and stretching on FDSSC performance. </LI> <LI> Photoelectric conversion efficiency retention rate of 95.95% after stretching to 100% strain. </LI> <LI> High flexibility with 97.00% performance retention rate at bending radius of 1 cm. </LI> </UL> </P>

Strategies for MSMEs to Achieve Sustainable Competitive Advantage: The SWOT Analysis Method

JATMIKO, Bambang,UDIN, Udin,RAHARTI, Rini,LARAS, Titi,ARDHI, Kholifah Fil Korea Distribution Science Association 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.3

The essential purpose of this study is to propose strategies for developing micro-, small-, and medium-sized enterprises (MSMEs) to realize sustainable competitive advantage by applying the SWOT analysis method. Thus, the main problems investigated in this study are: a) around 60-70% of MSMEs in Kulonprogo regency do not yet have access or financing from banks; b) lack of knowledge of production technology; c) in general, MSMEs business actors are still incorporated legal entities; d) MSMEs do not have a good financial administration and management system; e) coordination between MSMEs stakeholders has not been integrated; f) limited facilities and infrastructure of MSMEs, primarily related to technological tools; and g) limited access to raw materials so that MSMEs often get low-quality raw materials. This study employed a survey method with questionnaires and interviews. By using the Slovin tools sampling technique, the number of samples was 39 MSMEs in Kulonprogo Regency, Yogyakarta, Indonesia. The results of this study confirmed that the Kulonprogo MSMEs should pay attention to seven aspects of business management to achieve sustainable competitive advantage. The seven aspects are: 1) business strategy; 2) human resources; 3) information technology; 4) products; 5) promotion; 6) cooperation; and 7) corporate social responsibility (CSR).

Enhancing the biomass production of microalgae by mixotrophic cultivation using virgin coconut oil mill effluent

Resti Nurmala Dewi,Mahreni,M. M. Azimatun Nur,Al Ansor Siahaan,Arbayu Candra Ardhi 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.2

Skim is a major by-product of the virgin coconut oil (VCO) industry consisting of nutrients and is currently discharged to the environment as waste. Hence, this research aimed to utilize skim as a medium for Botryococcus braunii and Chlorella vulgaris growth. The effect of organic carbon resourced from glucose and glycerol on biomass was also investigated at certain concentrations with intervals 100:0 to 0:100 (%). Results indicated that Botryococcus braunii and Chlorella vulgaris cultivated under 20% VCO mill effluent gave the highest biomass production, which accounts for 1.69 g/L and 5.34 g/L; 89.40% and 86.70% COD reduction efficiency. Whereas, mixotrophic condition showed a positive trend for Botryococcus braunii at 80:20 (glucose:glycerol) with 5.60 g/L biomass production and 97.64% COD removal efficiency. Vice versa, the addition of glucose:glycerol gave an inhibitory impact on Chlorella vulgaris as the biomass production was merely 1.66 g/L with COD efficiency 94.03%.

Characteristics of living liver donors in a national referral hospital in Indonesia: a 13-year experience with living donor liver transplantation

Arnetta Naomi Louise Lalisang,Afid Brilliana Putra,Nathaniel Jason Zacharia,Vania Myralda Giamour Marbun,Lam Sihardo,Ridho Ardhi Syaiful,Febiansyah Ibrahim,Wifanto Saditya Jeo,Yarman Mazni,Agi Satria 대한이식학회 2023 Korean Journal of Transplantation Vol.37 No.3

Background: Hepatocellular carcinoma and biliary atresia lead to end-stage liver disease, which requires liver transplantation and is linked to increased mortality. Dr. Cipto Mangunkusumo Hospital is the national referral center in Indonesia and is the only center that routinely performs living donor liver transplantation (LDLT). This study presents the characteristics of living liver donors (LLDs) in Indonesia. Methods: Using the LDLT registry, we conducted a retrospective analysis of all approved donors from 2010 to 2022. The variables included clinical characteristics of the donors, graft types, and intraoperative and postoperative characteristics. Results: The LDLT rate has increased from 5.8 to 8.8 procedures/year in the last 8 years. The average age of the 76 LLDs was 31.8 years. They were predominantly female (59%) and lived within a family relationship (90%). Pediatric LDLT was more frequent than adult LDLT (88% vs. 12%, respectively). Most grafts (86%) were obtained by left lateral sectionectomy, with a median ratio of remnant liver volume to total liver volume of 79.5% (range, 47.7%–85.8%) and a mean graft-to-recipient weight ratio of 2.65%±1.21%. The median intensive care unit length of stay (LOS) was 2 days (range, 1–5 days) and the total hospital LOS was 7 days (range, 4–28 days). The complication rate was 23%. No donor mortality was reported. Conclusions: LDLT in Indonesia has increased over the years. The shortage of donors for adult-to-adult liver transplantation is due to cultural differences and challenges in finding eligible donors. This study aims to explain the eligibility criteria of LLDs and contribute to creating a national policy.