ANALISIS PENGARUH VARIASI MATERIAL CORE TERHADAP KUALITAS NIPPLE

This study aims to determine the effect of variations in core material made of iron and resin sand on the Nepel Brass smelter on hardness, surface results of castings, shrinkage, density apparent, time, and cost. To find out which core material is more efficient for use in large quantities. The product material used is Brass in the form of Hose Nipple with a size of 1/5 x 5/8 inch. The average specimen weight in this study was 8.33 gr. From the research conducted, the differences were found, namely the hardness of the smelting process with the core material of iron castings and resin sand is 37.14 BH 5 / 250-25 and 30.94 BH 5/250-25. Material defects found are in iron castings specimens, namely rough surface defects, pinhole, scrabs, gas holes and air voids with 19 points of defect points and an area of ​​78 mm or 10.57% of the inside area of ​​the specimen. Likewise with resin sand-coated specimens experiencing defects of Coarse Surface, Needle Hole, Scrabs, Gas Hole, Air Cavity and sand inclusion / erosion hardness, with large numbers almost covering all parts of the specimen or 95.1%. For shrinkage, cast specimens with iron castings are smaller at 0.35% and resin-coated specimens of 0.40%. For porosity defects, iron castings in the specimens were 8.33 and 8.40 in the core of the resin sand castings. The higher the true density, the more dense the material is. The production time is 555 seconds (9 minutes 15 seconds) from the smelting process of specimens with the core of resin sand castings which is for 829 seconds (13 minutes 49 seconds). Whereas for the process of releasing specimens from molds, products with resin sand castings are faster at 14 seconds, while for specimens with iron castings core is 28 seconds. The cost required to make specimens with iron cast core is Rp. 4,718,500, the cost is cheaper than the manufacture of specimens with core resin sand castings that require capital of Rp. 4,999,000.

Preliminary Synthesis of Calcium Silicates using Oil Palm Leaves and Eggshells.

A new synthetic procedure is described for the synthesis of calcium silicate derivatives, using natural resources such as eggshell (ES) for calcium and oil palm leaves (OPL) for silica, which do not require prepurification. The reaction is performed by directly converting two weight ratio of the precursors, ES:3OPL and ES:6OPL, to dried-powder form by heat treatment at 900 °C for two hours. The results demonstrate that the concentration of the precursors has an effect on the morphology and crystallinity of the calcium silicate derivatives, mainly Ca2SiO4 and CaSiO3. X-ray diffraction results reveal that the reaction product obtained using a 1:3 ratio is quite pure, and mainly consisted of calcium silicate in the form of Ca2SiO4. The CaSiO3 was also identified in ES:6OPL, together with a small amount of excess non-reacted crystalline silica. Furthermore, a scanning electron microscopy analysis shows that both reaction products have a coarse surface. Copyright © 2020 BCREC Group. All rights reserved

Synthesis of Graphene Oxide from Waste Carbon Tyre using Modified Hummer’s Method

Recently, graphene was produced from graphite powder using chemical vapour deposition (CVD) or Hummer’s method. Graphene is widely used in many applications and give a lot of advantages for industry. In this study, graphene oxide was synthesized from waste carbon tyre using modified Hummer’s method. This green technology turned waste material to wealth. The morphology and structural properties of the graphene oxide were investigated using Raman spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Raman analysis was confirmed that graphene oxide was successfully synthesized from waste carbon tyre. It was confirmed the peaks shows that D band and G band was at 1361 cm-1 and 1596 cm-1 with the intensity ratio of the D band relative to the G band (ID/IG) is 0.88. The formation of few sheets of grapheme oxide that stalked together on the surface of the sample structure, bumping pieces and coarse surface was confirmed by scanning electron microscopy (SEM). The elemental composition of carbon (C) is 50.90 % and oxygen (O) is 49.10% which showed a good composition for graphene oxide. All the results were confirmed that the graphene oxide has been synthesized from waste carbon tyre using modified Hummer’s method which next will forms graphene powder through exfoliation method.

Niobium-Treated Titanium Implants with Improved Cellular and Molecular Activities at the Tissue–Implant Interface

There have been several attempts to improve the cellular and molecular interactions at the tissue–implant interface. Here, the biocompatibility of titanium-based implants (e.g., Grade 2 Titanium alloy (Ti-40) and titanium–niobium alloy (Ti-Nb)) has been assessed using different cellular and molecular examinations. Cell culture experiments were performed on three substrates: Ti-40, Ti-Nb, and tissue culture polystyrene as control. Cells number and growth rate were assessed by cell counting in various days and cell morphology was monitored using microscopic observations. The evaluation of cells’ behavior on the surface of the implants paves the way for designing appropriate biomaterials for orthopedic and dental applications. It was observed that the cell growth rate on the control sample was relatively higher than that of the Ti-40 and Ti-Nb samples because of the coarse surface of the titanium-based materials. On the other hand, the final cell population was higher for titanium-based implants; this difference was attributed to the growth pattern, in which cells were not monolayered on the surface. Collagen I was not observed, while collagen III was secreted. Furthermore, interleukin (IL)-6 and vascular endothelial growth factor (VEGF) secretion were enhanced, and IL-8 secretion decreased. Moreover, various types of cells can be utilized with a series of substrates to unfold the cell behavior mechanism and cell–substrate interaction.

Electrodeposition of a Ni–P–TiO2/Ti3C2Tx Coating with in situ Grown Nanoparticles TiO2 on Ti3C2Tx Sheets

Protective coatings have received considerable attention for the surface treatment of devices. Herein, in situ grown nanoparticles, TiO2 on Ti3C2Tx sheets (TiO2/Ti3C2Tx), are prepared by a simple hydrothermal oxidation method possessing the layer structure, which is applied to prepare protective coatings. The Ni–P–TiO2/Ti3C2Tx coating is prepared by electroplating technology, revealing more excellent properties than those of the Ni–P coating. Compared with the Ni–P coating, even though the Ni–P–TiO2/Ti3C2Tx coating holds the rough surface, the wettability is changed from hydrophilic to hydrophobic, owing to the gathering existence of TiO2/Ti3C2Tx on the surface and coarse surface texture. In addition, the participation of TiO2/Ti3C2Tx in the Ni–P coating can improve the capacity of corrosion prevention and decrease the corrosion rate. According to the results of hardness and wear tests, microhardness of the Ni–P–TiO2/Ti3C2Tx coating is approximately 1350 kg mm–2 and the coefficient of friction (COF) of Ni–P–TiO2/Ti3C2Tx coatings is about 0.40, which is much lower than that of Ni–P coatings. Thus, the Ni–P–TiO2/Ti3C2Tx coating can be a promising material to protect the surface of equipment.

Nanocrystallisation of Nickel Free High Nitrogen Austenitic Stainless Steel through Ultrasonic Shot Peening

Ultrasonic Shot Peening (USP) - a novel route of surface modification was employed on biomedical grade Nickel free high nitrogen stainless steel (18Cr-21Mn-0.65N-balance Fe) to obtain a surface nanostructure without changing its chemical composition and microstructural phase transformation. Hardened steel shots of diameter 2 mm and 3mm were repeatedly impacted on the specimen surface at a constant frequency of 20KHz for 2 and 8 minutes duration. Coarse surface grains of size 36±6µm transformed into nanocrystalline grains of size 13-18 nm. The deformed layer resulted by USP treatment increased with increase in shot diameter and duration of USP. The microstructure was characterized by using optical microscope, SEM, XRD and TEM technique. The hardness and roughness of the treated surface was also found to be strongly dependent on the USP process parameters.

A pH-Responsive Multifunctional Nanocarrier in the Application of Chemo-Photodynamic Therapy

In cancer therapy, combined utilization of anticancer drug and photosensitizer attracts increasing interest due to enhanced curative effects and reduced side effects. Since the drug delivery system is an effective method to enhance curative effects, drug carriers for codelivery of the two abovementioned molecules are essentially important for chemophotodynamic therapy. Based on the foundation, a nanocarrier with pH-responsive and targeted properties was designed, prepared, and researched in the work. A pH-sensitive nanoparticle was fabricated by acetylated β-cyclodextrin (Ac-β-CD) using oil-in-water (O/W) emulsion technique. During the fabrication processing, a functional emulgator (gelation-folic acid ester (G-FA)) with a biorecognition domain was absorbed onto the surface of the nanoparticle, which endowed a nanoparticle-targeted property. The nanoparticle exhibited a coarse surface, pH-responsive property, and similar fluorescence characteristic as G-FA. The cell endocytosis profile revealed that equilibrium endocytosis could be reached after being cocultured with 1.0 mg/mL nanoparticle for 8 h. Furthermore, camptothecin (CPT) as an anticancer drug and phthalocyanine (PcZn) as a photosensitizer were encapsulated into the nanoparticle during the fabrication processing. The nanoparticle enhanced the fluorescence effects of PcZn on water solution, and CPT encapsulation proportion was slightly influenced by initial CPT concentration. The pH value influenced the PcZn fluorescence behavior and CPT release behavior of the nanoparticle. In vitro cytoviability evaluation confirmed the therapeutic effect of the nanocarrier on HEP2 cells. Finally, the results of preliminary in vivo evaluation revealed that the reported nanocarrier in the research could inhibit cancer development with little effects on the body weight of mice.

Assessment of the effects of wastewater treatment plant effluents on receiving streams using oligochaete communities of the porous matrix

Human activities can disturb the natural dynamics of exchanges between surface water and groundwater in rivers. Such exchanges contribute to the self-purification of the environment and an excess of infiltration can lead to contamination of groundwater. In addition, the porous matrix (coarse surface sediments and hyporheic zone), through which water exchanges occur, is a sink for pollutants. For environmental monitoring programs, it is therefore essential to take into account both the dynamics of vertical hydrological exchanges and the biological quality of this matrix. The functional trait (FTR) method, which is based on the study of oligochaete communities in coarse surface sediments and the hyporheic zone, was proposed as a tool to simultaneously assess the dynamics of vertical hydrological exchanges and the effects of pollutants present in the porous matrix. Here, we applied this method during two different periods (in March and September 2016), upstream and downstream of locations affected by discharges from wastewater treatment plants (WWTP) located in Switzerland. The biological quality of surface sediments and the hyporheic zone was shown to be better upstream of the WWTP in both campaigns. In addition, results suggested that the capacity for self-purification was lower downstream of the WWTP, and that groundwater at these locations was vulnerable to pollution by surface water. The FTR method proved valuable as a field method for detecting the effects of point source contamination on receiving streams. In the near future, this community-based approach will benefit from advances in the use of DNA barcodes for oligochaete species identification.

Importance of the Resolution of Surface Topography in Indian Monsoon Simulation

The influence of surface topography resolution in Indian summer monsoon simulation is investigated. Three sets of six-member ensemble simulations with climatological sea surface temperature are conducted with the Community Atmospheric Model, version 5.1 (CAM5.1): COARSE simulation at 1.9° × 2.5° latitude–longitude resolution, FINE simulation at 0.47° × 0.63° resolution, and HYBRID simulation, that is, using COARSE surface topography imposed on the FINE configuration. With regard to the representation of the surface topography, substantial differences occur at the regional scales between the simulations, especially over the foothills and steep flanks of the mountains. In the COARSE and HYBRID simulations, the orographic height of the foothills is overestimated whereas that of the steep flanks adjacent to the foothills is underestimated. The biases are severe (up to 1 km) over the Himalayas and Tibet and have detrimental effects on regional climate through barrier effects on the low-level flow, and the lapse rate and elevated heat source effects. Overall, the simulations show remarkable improvement with an increase in resolution, mainly because of the improved representation of atmospheric and surface processes. However, local climate—surface air temperature, sea level pressure, precipitable water, and wind—of the orographic regions, particularly where large orographic biases exist in COARSE, is found to benefit substantially from increased resolution of surface topography. Local precipitation and evaporation are exceptions, although, as they are negligibly sensitive to topographic resolution, showing strong dependence on the resolution of surface and atmospheric processes. Moreover, resolution of surface topography generally does not have notable remote impacts.

A New Route for Direct Electroless Ni-P Plating on Magnesium Alloys

This report describes a new route for direct electroless Ni-P plating on magnesium alloys using nickel sulfate as the main salt component. The surface morphology, chemical composition and corrosion resistance of coatings were determined using SEM, EDX and electrochemical polarization techniques. Ni-P coatings with good corrosion resistance and high adhesion were obtained using this route and improved pretreatments. A mixture of H3PO4 and HNO3 was used as a pickling solution for Mg substrate pretreatment. A coarse surface was produced via the developed pickling procedure. A mechanical occlusive force is believed to exist between the coatings and the substrates. Twice activations, K4P2O7 and NH4HF2 as activation components, respectively, were applied for the pretreatment of magnesium alloy plating. An optimal F/O ratio on the Mg substrate surface was obtained by this pretreatment method. The activation film has insoluble partial fluorides which can depress the active points on substrate surface against the reaction of Mg with Ni2+ and H+ in the plating bath. A highly stable bath with pH 5 buffer was identified. The advantages of the developed process include chromium-free, low fluoride, and high bath stability. It is applicable for the production of motorcycle part plating.