Mold Casting Technique Research Articles

Enhancement of tensile strength and fracture toughness characteristics of banana fibre reinforced epoxy composites with nano MgO fillers

Natural fibre reinforced polymer composites have drawn the attention of researchers in the creation of novel materials suitable for industrial applications. These polymer composites have favourable mechanical characteristics. Epoxy polymer's versatility and diversity make it suitable for a wide range of industrial applications. The mould casting technique approach was utilised in this work to develop polymer composites using alkali-treated banana fibres and filled with MgO nanoparticle. The study was conducted on the characteristics of Nano MgO, as well as its mechanical qualities such as fracture toughness and surface morphology. The incorporation of Nano MgO enhanced the fracture toughness of the polymer composites with the addition of 1 % MgO. The scanning electron microscopy analysis of the surface morphology revealed the presence of brittle fracture in the specimen.

Experimental investigation of compressive behavior and vibration properties of layered hybrid foam formed by aluminum foam/EPS-filled syntactic foam

Hybrid foams are a type of composite material created by combining two foam materials. They are preferred in many applications due to their lightweight, high strength, and ability to absorb more energy. In this research, a new hybrid foam was designed for use in sandwich cores of structural materials. The hybrid foam was formed by combining closed-cell aluminum foam and expanded polystyrene (EPS)-filled syntactic foam. The EPS-filled syntactic foams were produced with the conventional mold casting technique. Uniaxial compressive behaviors (0.5 mm/min) of layered hybrid foams consisting of EPS-filled syntactic foam with three different densities and closed-cell aluminum foam were investigated experimentally and compared with conventional single-foamed materials. These results exhibited that in general, layered hybrid foams outperform conventional single-foamed materials in terms of compressive strength. Moreover, the natural frequency and damping ratio of the layered hybrid foams were investigated by vibration tests under clamped-free and free-free boundary conditions and compared to conventional single-foamed materials. It was established that the vibration damping capacity of the layered hybrid foams improved compared to the closed-cell aluminum foam. Additionally, the microstructure of the conventional single-foamed materials was examined by SEM. In the outcome of the research, the experimental results showed that layered hybrid foam provides an opportunity to design lightweight cellular materials with effective mechanical properties.

Effect of sodium content on the structure and mechanical properties of silicon bronze (Cu-3wt%Si alloys)

In the present study, the effect of sodium content on the structure and mechanical properties of Cu-3wt%Si alloys were investigated. The experimental alloys were produced with various sodium concentrations of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2 and 3% by weight using permanent mould casting technique. Tensile and hardness tests were carried out on the cast samples. Microstructures of the specimens were also analysed using optical microscopy. The results indicated that the addition of sodium to Cu-3wt%Si alloy refined and modified the structure of the alloy resulting in improvement in the ultimate tensile strength and hardness of the experimental alloy by 453.85% and 58.82% respectively at 1.5wt%Na content and percentage elongation by 168.81% at 0.1wt%Na content. The addition of sodium also led to the formation of the Na1.44Si136 intermetallic phase which further contributed to the increase in strength and hardness of the alloy.

Crystallization kinetics and mechanical property of yttrium-modified Zr-Cu-Ag-Al bulk metallic glasses

The bulk metallic glasses of two different compositions i.e. Zr44Cu40Al8Ag8 and Zr44Cu40Al8Ag7Y1 were prepared by copper mold casting technique in this study. As-cast microstructure both BMG’s found to completely amorphous as depicted by X-ray diffraction and transmission electron microscopy. The differential scanning calorimetry (DSC) results reveal that Y-addition leads to an increase in the nucleation rate at the initial stages of crystallization but imposes resistance to the growth of the crystalline phases at later stages. Furthermore, the Y-addition results in better creep resistance for Zr44Cu40Al8Ag7Y1 glassy alloy at room temperature.

Effect of Caesalpinia decapetala on the Dry Sliding Wear Behavior of Epoxy Composites

The present research investigates the wear characteristics of an epoxy composite reinforced with a novel Caesalpinia decapetala (CD) shell. The CD is available abundantly worldwide, especially in Ethiopia, particularly in East and West Oromia near West Harar. The composite specimens were processed in the open mould casting technique by varying the vol.% of CD in 10, 20, and 30. EDS is used to evaluate the important elements present in the CD. The density of composites increases with the increase in the content of CD, while the void content estimations reveal good control over the composite fabrication. The wear response of composites is investigated by varying the sliding distance and load and by maintaining a fixed velocity (5 m/s). At a 5 km slide distance and 50 N load, the 30 vol.% Caesalpinia decapetala composition depicts better wear resistance and friction coefficient than other compositions. Experimental results are used to envisage the ideal wear factors and to assess the influence of parameters over the two wear objectives, wear rate and CoF. The grey relational analysis- (GRA-) coupled artificial neural network (ANN) hybrid technique was employed for the prediction and validation. It has been observed that a trivial error of 0.49% amidst GRA and ANN estimation is observed.

Development of cell-laden multimodular Lego-like customizable endometrial tissue assembly for successful tissue regeneration

BackgroundThe endometrium, the inner lining of the uterine cavity, plays essential roles in embryo implantation and its subsequent development. Although some positive results were preliminarily archived, the regeneration of damaged endometrial tissues by administrating stem cells only is very challenging due to the lack of specific microenvironments and their low attachment rates at the sites of injury. In this context, various biomaterial-based scaffolds have been used to overcome these limitations by providing simple structural support for cell attachment. However, these scaffold-based strategies also cannot properly reflect patient tissue-specific structural complexity and thus show only limited therapeutic effects.MethodTherefore, in the present study, we developed a customizable Lego-like multimodular endometrial tissue architecture by assembling individually fabricated tissue blocks.ResultsEach tissue block was fabricated by incorporating biodegradable biomaterials and certain endometrial constituent cells. Each small tissue block was effectively fabricated by integrating conventional mold casting and 3D printing techniques. The fabricated individual tissue blocks were properly assembled into a larger customized tissue architecture. This structure not only properly mimics the patient-specific multicellular microenvironment of the endometrial tissue but also properly responds to key reproductive hormones in a manner similar to the physiological functions.ConclusionThis customizable modular tissue assembly allows easy and scalable configuration of a complex patient-specific tissue microenvironment, thus accelerating various tissue regeneration procedures.

Flexural strength of biopolymer coated bioactive glass (45S5) sintered struts for bone tissue engineering applications

Owing to its bioactivity and proven biological performance, 45S5 bioactive glass (BG) is considered a convenient choice to fabricate scaffolds for bone tissue engineering applications. However, the brittleness of the material in conjunction with microstructural imperfections can cause catastrophic fracture and thus unreliable mechanical performance. This experimental study probes the fabrication of 45S5 BG struts using mold casting technique and sintering followed by the coating of the fabricated struts with gelatine and polycaprolactone (PCL) to improve the mechanical properties. The mechanical properties of struts were measured using a four-point bending test. The results indicate an improvement in flexural strength of the struts after coating with PCL. The uncoated and gelatin-coated samples exhibited flexural strength of around 20 MPa, which was increased to 55 MPa and 70 MPa after coating with PCL of 14 k and 80 k molecular weight, respectively. Careful evaluation of the test results permits quantifying the flexural strength of struts.

Performance evaluation of different carbide inserts in turning of newly developed Al‐12Si‐0.1Sr alloy

AbstractAn Al‐12Si‐0.1Sr alloy ingot was manufactured using a permanent mold casting technique. The microstructure and mechanical properties of this alloy were researched. Effects of different cutting conditions (cutting speed‐V: 200 m/min, 300 m/min, and 400 m/min and feed rate‐f: 0.05 mm/rev, 0.1 mm/rev, and 0.15 mm/rev) on the cutting force (F) and surface roughness (Ra) during machining using uncoated and physical vapor deposition‐ titanium aluminum nitride coated carbide inserts were also revealed. Microstructure of the alloys consists of α phase, intermetallic δ and Al4Sr phases, thin spherical eutectic, and irregular coarse‐shaped primary silicon particles. Cutting force and surface roughness decreased with the increased cutting speed during turning with uncoated, and titanium aluminum nitride coated inserts while they increased feed rate. A built‐up edge and built‐up layer were formed in both cutting inserts. The built‐up edge and built‐up layer decreased with increasing cutting speed and increased feed rate. The cutting force, surface roughness, built‐up edge, and built‐up layer were lower in uncoated inserts compared to the titanium aluminum nitride coated inserts.

Effect of various nanofillers on the insulating properties of polyethylene composites

This work focuses on the preparation of various inorganic nanoparticles i.e. Al2O3, SiO2, TiO2 including the waste glass powder filled in high-density polyethylene (HDPE H455JA) matrix to create high-performance composites. The glass powder prepared from broken windowpane was used in this study in order to use as a guideline to find substitutes for commercial materials and also add value to waste and reduce costs. The 2 wt% of each filler was weighed and mixed with HDPE to create a composite by using a simple mold casting technique. The physical, chemical and electrical properties were investigated for all samples. The results show that the εr value of the pure HDPE and the HDPE-based composites are approximately the same in all frequencies and the εr of pure HDPE tends to decrease about 7.8% at elevated temperature, whereas the εr value of composites is less decreased at higher operating temperatures for all samples which can imply that the composites are more capable of operating at higher temperatures than pure HDPE itself. For the electrical resistivity, the ρ value gradually increases at elevated temperature for all samples and the composites show a higher ρ value than that of pure HDPE.

Polymer-Coated Polymeric (PCP) Microneedles for Controlled Dermal Delivery of 5-Fluorouracil.

Polymeric microneedles were prepared with Polyvinyl Pyrrolidone (PVP) K-30 using the mold casting technique. The core microneedles were coated with Eudragit E-100 by dip and spin method. The amount of 5-fluorouracil (FU) loaded in the core microneedles was 604 ± 35.4µg. The coating thickness was 24.12 ± 1.12µm. The objective was to deliver the 5-FU gradually in a controlled release manner at the target site in the sub-stratum corneum layer. This approach is anticipated to improve the safety and efficacy of topical melanoma treatment. The release of the drug was prolonged for up to 3h from the polymer-coated polymeric (PCP) microneedles. The entire amount was found to release within 15min in uncoated MNs. Likewise, the permeation of the drug from the uncoated microneedles was rapid, whereas the PCP microneedles were able to prolong the permeation up to 420min. The PCP microneedles were subjected to stability studies at 25°C ± 2°C/60%RH, and 40°C ± 2°C/75%RH condition for 3months. The formulations were found intact, and the release rate was not significantly different form the fresh formulation. The drug content was found to meet the acceptability criteria as well (98.12 ± 1.8% and 97.8 ± 2.1% at 25 and 40°C respectively after 3months). Overall, this study demonstrated the feasibility of fabrication of PCP microneedles using Eudragit E100 for intraregional controlled delivery of drugs.

Efecto de la sustitución parcial de Cr con Co sobre la capacidad de formación de vidrio, propiedades mecánicas y magnéticas en vidrios metálicos a granel Fe48Mo14Cr15-xCoxB6P8Si7Y2

Fe-based BMGs are well known for its attractive combination of structural, magnetic and corrosion properties. These alloys are widely used in industry because of low price and good glass forming ability (GFA). In this paper, the effect of partial substitution of Cr with Co on GFA, mechanical and magnetic properties of Fe48Mo14Cr15-xCoxB6P8Si7Y2 bulk metallic glasses was studied. The samples were prepared by copper mold casting technique in rod form. The elaborated alloys were structurally investigated by X-Ray diffraction (XRD) and differential scanning calorimetry (DSC), while the mechanical properties were investigated by compressive and nanoindentation tests. Also, the magnetic properties were investigated. The GFA was estimated by several criterion or parameters (reduced transition temperature Trg, ΔTx, α, β, γ and δ parameters). It was found that the addition of Co instead of Cr leads to a slight increase of the glass forming ability of Fe-Mo-Cr-B-P-Si-Y family. Also, an increase in magnetic properties, hardness, elastic modulus and compressive strength has been noted.

Experimental research on machinability characteristics of Al-9Si alloy: Effect of Sr and Mg additives

In this study, the effects of strontium (Sr) and magnesium (Mg) elements in certain rates added to Al-9Si alloy manufactured using permanent mold casting technique on the structural, mechanical, and machinability properties of these alloys were investigated. While microstructural images of the alloys were obtained with an optical microscope, hardness, tensile strength, and elongation to fracture were determined by conventional methods. The resultant cutting force ( F) and average surface roughness ( Ra) were measured as experimental outputs in the turning process. It was observed that Al-9Si alloy comprised of α-Al, eutectic Al-Si, β, and primary Si phases. The addition of Sr to the Al-9Si alloy led to the formation of the Al4Sr phase and the transformation of the β phase into the δ phase. The addition of Mg to Al-9Si-0.1Sr alloy caused the δ phase to transform into the π phase. The hardness of the tested alloy increased significantly with the Mg addition. The yield strength and tensile strength of them increased with both Sr and Mg additions. On the other hand, elongation to fracture value of the Al-9Si alloy increased with Sr addition while it decreased with the Mg addition. The F and Ra values obtained from the Al-9Si alloy increased with Sr addition in the turning process while decreased with Mg addition. The results obtained from turning tests were discussed based on the mechanical properties of alloys.

Experimental investigation on the flexural response of epoxy composites filled with environmental pollutant crump rubber

Flexural response of crump rubber filled epoxy composites is reported in the present work. Composites are fabricated using open mold casting technique and test specimens are evaluated at normal strain rate. Stress strain profiles of all the specimens reveal brittle mode of fracture. Modulus of crump rubber composites increase with increasing crump rubber content owing to good bonding of constituents and higher elasticity induced by crump rubber particles. Neat epoxy specimens reveal lower modulus than all the composites filled with crump rubber. Strength of all the composites are higher as compared with neat epoxy and increase as the crump rubber content is increased. Composites filled with 30 vol% of crump rubber reveals highest modulus (24%) and strength (22%) in comparison with neat epoxy and all other compositions. Scanning electron microscopy of specimens are analyzed to study the structure property correlations. Mapping of results from the current work and existing ones are compared using property chart.

Microneedle patch-assisted transdermal administration of recombinant hirudin for the treatment of thrombotic diseases

The painless microneedle patch (MNP), widely explored for transdermal drug delivery of macromolecules, can overcome the limitations of traditional administrations of protein and polypeptide anticoagulant drugs. We constructed a recombinant hirudin-loaded microneedle patch, suitable for patients with thrombotic diseases requiring long-term preventive medication. The recombinant hirudin-loaded dissoluble microneedle patch (RHDMNP) was created using a mold casting technique and polyvinylpyrrolidone and polyvinyl alcohol were used as the matrix material with a 1:1.2 ratio. We prepared bilayer RHDMNPs with pyramidal appearance and 0.37 N/needle strength. The intradermal dissolution height of the microneedle reached approximately 78.67% of the total height, and 68.12% of the drug was delivered into the skin. The 12-hour cumulative permeation of the MNP was 21.69 ± 3.90 μg/cm2. The MNP showed a Tmax of 1.5 h, Cmax of 144 ± 71 ng/mL, and area under curve (AUC) of 495 ± 66 ng/mL·min compared to Tmax of 0.5 h, Cmax of 249 ± 89 ng/mL, and AUC of 944 ± 65 ng/mL·min for the subcutaneous injection group. Both in vivo and in vitro experiments showed that the RHDMNP exerted effective anticoagulant effects, prevented the incidence of acute pulmonary embolism, and revealed the potential for venous thrombosis prevention.

MECHANICAL PROPERTIES AND WEAR BEHAVIOUR OF KAOLINITE CLAY PARTICLES REINFORCED EPOXY MATRIX COMPOSITES

Epoxy matrix composites reinforced with clay particles were developed by hand lay-up open mould casting technique. The clay used in this study was pulverized and processed into ultrafine particles through the sedimentation process. The composites were developed by blending the epoxy matrix and hardener with various weight fractions of the ultrafine clay particles (2, 4, 6, 8 and 10 wt%) in open test moulds. In order to accomplish a homogeneous blend of the constituents; manual mixing of the blend was carried out for 3 min. The test specimens were left to cure for 24 hours in the moulds and for additional 27 days at room temperature of 27 ± 2 °C and were thereafter detached from the moulds. The developed composites test specimens were subjected to mechanical tests (flexural, tensile and impact) in accordance with ASTM standards and performed at room temperature. Structural characteristics of the clay particles were determined with the aid of an X-ray diffractometer (XRD). The morphologies of the composites were determined using a scanning electron microscope (SEM). There was a progressive enhancement in the mechanical properties of epoxy composites containing 2-6 wt.% ultrafine clay particles while a drastic decrease in the mechanical properties was noticed in the epoxy/clay composites reinforced with 8-10 wt.% ultrafine clay particles. The SEM images revealed homogeneous particles distributions within the epoxy matrix at lower ultrafine clay particles weight fractions (2 wt. % and 6 wt.%).

Investigation of shell mold casting technique in Ghana using indigenous materials

Shell mold casting processes are more cost-intensive in terms of equipment, raw materials, and skills than the sand-casting technique. Sand casting is practiced in Ghana to cast mainly corn mill plates and occasionally vehicle and machine parts that lack good surface finish, better dimensional accuracy, and require a lot of effort/energy to bring the cast to the actual specification. As a result of the limitations of the sand-casting technique, the shell mold casting technique was adapted in this work. Indigenous clay chemically composed of 69.8% silica; 15.7% alumina was used. Washed and unwashed Silica from the Yakor River were investigated. The combination of clay, silica, and water was used to form a mold for the casting of a machine component. Of all the mixtures that were fired, the best mixture ratio was the sample which has the composition of 70% Mfensi clay, 10% silica sand, and 20% water selected from sixty-six samples. The mixture was tested based on its compressive strength and other parameters such as Acid Demand Value, pH Value, and Grain Fineness Number. Chemically, the final mold had a thickness of 16 mm which was able to withstand the high temperature (1450 °C) of the molten cast iron without the shell mold collapsing. A shell core made exhibited better core properties such as collapsibility, thermal stability, and permeability when the molten cast iron was poured into the mold for solidification.

Fabrication and development of controlled release PLGA microneedles for macromolecular delivery using FITC-Dextran as model molecule

The use of biodegradable polymers has been prominent in the field of drug delivery due to its degradability and biocompatible properties. These polymers when used to prepare microneedles, impart high mechanical strength, sustained drug release profile, and long term biocompatibility. In this study, PLGA (poly (D, L-lactic co-glycolic acid)) and PVA (Polyvinyl Alcohol) were used in combination to optimize the microneedle fabrication for high molecular weight FITC Dextran (4 kDa MW) to be used as a model drug. FITC-Dextran loaded PLGA microneedles were fabricated using a mold casting technique. MNs were characterized for the textural properties, FITC-Dextran release profile, and in-vitro permeation profile. The fate of microneedles in the skin (ex vivo) was characterized using fluorescence and confocal imaging. The FITC -Dextran MNs (10 × 10 array) had a dimension of 415 ± 2.65 μm height, 207 ± 1.63 μm width of the base and a needle pitch of 463 ± 1.45 μm. The texture analysis data showed puncture force for FITC-Dextran loaded PLGA microneedles (28.46 ± 0.23 g) and PLGA microneedles (16.92 ± 0.04 g). The Cumulative permeation of FITC-Dextran after 48 h was 2.34 ± 0.40 μg/cm2 and it showed a 31 fold higher permeation profile than its respective control. Ex vivo imaging studies were used to characterize the fluorescence intensity of FITC-Dextran in the skin. This study demonstrates that incorporating higher molecular weight molecules into PLGA microneedles proved to be an effective strategy to sustain the release of macromolecules across stratum corneum/epidermis for transdermal delivery.

Waste Fly Ash Powder Filled Glass Fiber Reinforced Epoxy Composite: Physical, Mechancial, Thermo-mechanical, and Three-body Abrasive Wear Analysis

In the present research work, waste fly ash powder-filled chopped glass fiber reinforced epoxy composites are fabricated. Conventional open mold casting technique is used for fabrication of composite samples. The fly ash powder is incorporated from 0 to 15 wt.% in the composite at an interval of 5 wt.% to analyze the physical (experimental and theoretical densities, void fraction and hardness), mechanical (tensile strength, tensile modulus, flexural strength, flexural modulus, impact strength), thermo-mechanical (dynamic mechanical analysis, DMA), and three-body abrasive wear rate, respectively. From this study, it is clearly seen that density, void fraction, and hardness of the composites improved with fly ash content. The strength and modulus of the composites increased with filler content up to 10 wt.%. For the analysis of the homogeneity of composites, the storage modulus, loss modulus, and the cole-cole plot are drawn from dynamic mechanical analysis. Finally, a three-body abrasive wear test is conducted for composite samples, in a steady-state abrasive wear condition up to 10 wt.% fly ash filled composites shown better wear resistance with the variation in sliding distance and normal load. The Taguchi’s design of experiment method is used for designing of experimental runs having input controlling variables like sliding distance, normal load, filler content, and abrasive size.

A study of the optical transmission spectra of polyester resin-based glass fabricated by open mold cast technique

Polyester resin is a thermoset resin commonly used in the production of polymer composites. Polyester resin is a polymer matrix that is easily available and widely used by the general public and industry. Besides, this resin is cheap, has unique characteristics, namely that it can be made rigid and flexible. This research aimed to investigate the optical transmission spectra of polyester resin-based glass fabricated by open mold casting technique with different MEKPO or methyl ethyl ketone peroxide concentrations in the visible region. This research used Yukalac C 108B polyester resin. Catalyst MEKPO was added with three variations, 1%, 2%, and 5%. The prepared mixture was then set at 30 Celsius degree and 1000 RPM for five minutes by a magnetic stirrer. The optical transmission spectra of the glass were measured using optical emission spectroscopy. The result shows that the optical spectra of this polyester resin-based glass possess higher transmission in the region at 650 nm to 700 nm and the amount of catalyst that can produce polyester resin glass material by open mold cast technique with higher optical properties at 1% catalyst composition.

Investigation Wear Behaviour of Tin Bronze Alloy Prepared by Different Casting Techniques

The cement industry is one of the essential industries in Iraq that has taken a wide range of attention in many applied fields, but this industry faces some technical and engineering problems. One of these problems may cause consumption sliding bearing used in the kiln rotary of the Kufa cement plant. In this study, the effect of Antimony as an alloying element on the wear resistance behavior of tin bronze alloys produced by die and sand mold casting technique was investigated. The alloying element (Sb) was added with a percentage of 3, 5, and 8 wt. %. Wear tests were carried out using pin-on-disc. In the wear test, the applied load and rotating speed were selected to be 10, 20, 30 N, and 250 rpm, respectively. The prepared alloys have been characterized using the SEM and XRD techniques. It was concluded that the loss of CuSn12 alloy produced by the die mold casting technique was lower due to its higher hardness and wear resistance increased in general with increasing the applied load. The tin bronze + 8 wt% Sb has more wear resistance than tin bronze +5 wt% Sb, tin bronze +3 wt% Sb, and tin bronze alloys.