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Optimization and Simulation of Plastic Injection Process using Genetic Algorithm and Moldflow

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Chinese Journal of Mechanical Engineering 2017年第2期30卷 398-406页

作者： sigit Yoewono Martowibowo Agung Kaswadi Faculty of Mechanical and Aerospace Engineering Institut Teknologi BandungBandung 40132Indonesia Politeknik Manufaktur Astra Jakarta 14330Indonesia

The use of plastic-based products is continuously increasing. The increasing demands for thinner products, lower production costs, yet higher product quality has triggered an increase in the number of research projects on plastic molding processes. An important branch of such research is focused on mold cooling system. Conventional cooling systems are most widely used because they are easy to make by using conventional machining processes. However, the non-uniform cooling processes are considered as one of their weaknesses. Apart from the conven- tional systems, there are also conformal cooling systems that are designed for faster and more uniform plastic mold cooling. In this study, the conformal cooling system is applied for the production of bowl-shaped product made of PP AZ564. Optimization is conducted to initiate machine setup parameters, namely, the melting temperature, injection pressure, holding pressure and holding time. The genetic algorithm method and Moldflow were used to optimize the injection process parameters at a minimum cycle time. It is found that, an optimum injection molding processes could be obtained by setting the parameters to the following values： TM=180℃; Pinj = 20MPa; Phold= 16MPa and thold=8s, with a cycle time of 14.11 s. Experiments using the conformal cooling system yielded an average cycle time of 14.19 s. The studied conformal cooling system yielded a volumetric shrinkage of 5.61% and the wall shear stress was found at 0.17 MPa. The difference between the cycle time obtained through simulations and experiments using the conformal cooling system was insignificant （below 1%）. Thus, combining process parameters optimization and simulations by using genetic algorithm method with Moldflow can be considered as valid.

关键词： Conformal cooling Parameters optimization Genetic algorithm Moldflow Cycle time

Gastric ulcer healing effect of wild honey and its combination with Turmeric(Curcuma domestica Val.) Rhizome on male Wistar rats

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Journal of Chinese Pharmaceutical Sciences 2014年第12期23卷 844-849页

作者： I Ketut Adnyana Joseph I.sigit Larasati A.Kusumawardani School of Pharmacy Bandung Institute of Technology

Gastric ulcer is a common disorder in human at any ages. In this research, the antiulcer activity of wild honey produced by Apis dorsata, alone or in combination with Turmeric Rhizome, was evaluated in healing acute gastric ulcer. Male Wistar albino rats(150–250 g) were induced ulcers with aspirin at 405 mg/kg BW and ethanol. Antiulcer evaluation was done based on the gastric acidity, numbers and diameter of ulcers, ulcer index, healing ratio, histological examinations, and body weight. The results showed that the groups given honey alone, turmeric alone, and combination of turmeric-honey displayed significant ulcer healing compared to the control group. Ulcers in the group administered with combination of turmeric-wild honey was different significantly from the turmeric alone and wild honey alone groups with increased body weight in that group. The result showed that wild honey(2125 mg/kg BW) had the greatest activity in healing ulcers among other groups. The combination of turmeric-wild honey had a good activity in healing ulcers and increased the body weight of the group.

关键词： Apis dorsata Aspirin Gastric ulcer Turmeric Wild honey

How far is Lignin from being a biomedical material?

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Bioactive Materials 2022年第2期7卷 71-94页

作者： sigit Sugiarto Yihao Leow Chong Li Tan Guan Wang Dan Kai Institute of Materials Research and Engineering(IMRE) A*STAR2 Fusionopolis WayInnovis#08-03Singapore 138634 Singapore Department of Biomedical Engineering National University of Singapore4 Engineering Drive 3Singapore 117583Singapore

Lignin is a versatile biomass that possesses many different desirable properties such as antioxidant,antibacterial,anti-UV,and good *** lignin can be processed through several chemical *** processed lignin can be modified into functionalized lignin through chemical modifications to develop and enhance ***,lignin is one of the prime candidate for various biomaterial applications such as drug and gene delivery,biosensors,bioimaging,3D printing,tissue engineering,and dietary supplement *** review presents the potential of developing and utilizing lignin in the outlook of new and sustainable ***,we also discuss on the challenges and outlook of utilizing lignin as a biomaterial.

关键词： Biomass Biomedical applications Antioxidants Tissue engineering 3D printing

Probabilistic Assessment of Pitting Corrosion Effect on Flexural Strength of Partial Prestressed Concrete Structures in a Chloride Environment

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Journal of Civil Engineering and Architecture 2010年第2期4卷 25-32页

作者： Muhammad sigit Darmawan Department of Civil Engineering Institut Teknologi Sepuluh Nopember （ITS） Surabaya 60111 Indonesia

Like reinforced concrete （RC） structure, Prestressed concrete （PC） structures cannot escape from corrosion related problems, especially when they are subjected to very aggressive environment, such as chloride environment. The corrosion of PC and RC structures can take place if the concrete quality is not adequate, the concrete cover is less than that specified in the design, poor detailing during design and construction. For RC structures, corrosion in the reinforcing steel generally leads to serviceability problems （staining, cracking and spalling of concrete）. By contrast, for PC structures, corrosion of prestressing strands may initiate structural collapse due to higher stress levels in the steel and smaller diameter of the prestressing steel. Research on corrosion effect on concrete structure has mainly considered the effect of corrosion have on reinforced and full prestressed concrete structure. In this study, a structural framework will be developed to predict the flexural strength of partial prestressed concrete structures in a chloride environment. The corrosion model previously developed for reinforced and prestressed concrete structures will be combined to predict the effect of corrosion has on partial prestressed concrete structures. Note that in partial prestressed concrete structures, both non prestressing steel （passive） and prestressing （active） reinforcement are utilized to carry the load. The framework developed will be combined with probability analysis to take into account the variability of parameters influencing the corrosion process. This approach allows more accurate prediction of service life of partial prestressed concrete structures in a chloride environment.

关键词： Corrosion partial prestressed concrete structure chloride probability.

Build mutant and build homology protein structure predictions for indonesian avian influenza neuraminidase

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Journal of Biophysical Chemistry 2012年第2期3卷 183-190页

作者： sigit Jaya Herlambang Rosari Saleh Departemen Fisika Fakultas MIPA Universitas Indonesia Depok Indonesia

Protein structure modeling using a homologous template is one of many routines that accompany the molecular dynamics simulation for biological material. There are currently two protocols of protein modeling available in Accelrys Discovery Studio 2.1, Build Mutants and Build Homology Modeling protocols. Both are template-based modeling, but with a different process. In this study, two different templates, 3CKZ and 274Y, have been used to see how much the differences will be made by those two protocols if the templates has significant percentage of identity. Evaluation of structure models has been performed using DOPE score, 3D-profile, and PROCHECK. The results indicated that Build Mutants Protocols produces more stable structures but has a low reliability values and low quality of stereochemistry when using a template that has a lower percentage of identity. The results also yield more stable, reliable, and higher percentage of residues in most favoured and additionally allowed region for the usage of Build Homology Modeling Protocol on both templates. These observations suggest that Build Homology Modeling protocol is recommended for protein modeling.

关键词： Protein Modeling Mutation Build Model Protocols

Indonesian avian influenza H274Y mutant neuraminidase homology models assessment

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Journal of Biophysical Chemistry 2011年第3期2卷 345-352页

作者： sigit Jaya Herlambang Rosari Saleh Departement of Physics Mathematics and Science Faculty University of Indonesia Depok Indonesia 16424

Five models of Indonesian H274Y mutant neuralminidase type 1 (N1) were generated from the template 3CKZ by homology modeling. The template has the best similarity percentage 97% with the model sequence. The models was evaluated to search the best model with DOPE, 3D-profiles and PROCHECK in a good rank. The results show model 3 as a potential model to be used in the simulation with the lowest DOPE score, highest verify-3D score and from Ramachandran plots we inferred that it also shared the 1st rank with model 4 based on the 99.4% of the residues found, without Glycine and Proline, at the most favoured and additionally allowed region of both model structures.

关键词： Neuraminidase Model Assessment Homology Model Mutant Avian Influenza

Molecular docking investigation for Indonesian H274Y mutant neuraminidase type 1 with neuraminidase inhibitors

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American Journal of Molecular Biology 2012年第1期2卷 49-59页

作者： sigit Jaya Herlambang Rosari Saleh Department of Physics Mathematics and Science Faculty University of Indonesia Depok Indonesia

The aim of this study is to get insight the interaction between Indonesian H274Y mutant neuraminidase with four inhibitors. Not only to seek preferable inhibitor to be used, but also to investigate the interaction occurred, especially hydrogen bonds formed. Hydrogen bonds analysis and its interaction energies calculation showed that zanamivir is the most preferable inhibitor with 13 hydrogen bonds formed and –439.96 kcal/mol. Laninamivir would be an alternative inhibitor since it has 10 hydrogen bonds and –307.19 kcal/mol. The investigation of ΔSAS showed almost all active site residues buried when interacted with inhibitors. Only a few residues have an increases ΔSAS. Lipinski rule analysis showed that zanamivir and laninamivir would be best taken by injection or inhalation.

关键词： Molecular Docking Neuraminidase Inhibitor Resistance

Pathogenicity characterization with implicit and explicit molecular dynamics simulation

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Natural Science 2011年第12期3卷 1022-1028页

作者： sigit Jaya Herlambang Rosari Saleh 不详

The contribution of water molecules in molecular dynamics simulation (MDS) is unquestionably high, particularly for enzymatic interaction which occurred in the cytoplasmic environment. The addition of water molecules to the system will surely influence different direct interaction between active site residues and substrate. We try to theoretically investigate to what extent the pathogenicity characterization will varies in different neuraminidase-sialic acid complex systems. The heating dynamics simulations were produced with and without TIP3P water molecules. The periodic boundary system was made for explicitly added TIP3P water molecules and generalized born molecular volume (GBMV) energy contribution was added for implicit solvent system. Both complexes, neuraminidasesialic acid of A/Tokyo/3/67 and A/Pennsylvania/10218/ 84, which have a different pathogenicity levels were minimized and simulated. The result shows more residues produced hydrogen bonds with substrate when water molecules were not added to the system. The binding free energies also show differences. Overall, even the values of energy differences, but an implicit solvent provides the similar result (HPAI complex has higher activity than LPAI for both systems) in characterization of pathogenic virus neuraminidase activity.

关键词： Implicit Explicit Solvation Molecular Dynamics Simulation Neuraminidase Sialic Acid

The Comparison of Substrate Stability in Neuraminidase Type 2 (N2) Active Site between A/Tokyo/3/67 and A/Pennsylvania/10218/84 with Heating Dynamics Simulation

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World Journal of Condensed Matter Physics 2011年第3期1卷 77-87页

作者： sigit Jaya Herlambang Rosari Saleh Departement of Physics Mathematics and Science Faculty University of Indonesia Depok Indonesia 16424

A molecular dynamics simulation of two neuraminidase-sialic acid (NA-SA) complexes show a difference of the level of stability between sialic acid and neuraminidases that originated from viruses A/Tokyo/3/67 (Structure A) dan A/Pennsylvania/10218/84 (Structure B). Analyses of sialic acid RMSD and the change of torsional angles suggest that the sialic acid in Structure A is much more twisted and able to be influenced more by the binding of the neuraminidase functional residues than Structure B. Moreover, analyses upon hydrogen bond occupancy and binding free energy of both complexes showed that Structure A had more stable hydrogen bonds and each complex’s binding free energy were calculated to be –1.37 kcal/mol and 17.97 kcal/mol for Structure A and Structure B, respectively, further suggesting stability more dominant in Structure A than Structure B. Overall, Structure A has a more stable enzyme-substrate than Structure B.

关键词： Neuraminidase Sialic Acid Bind Stability Functional Residues Avian Influenza