scholarly journals OPTIMISATION OF A RESIN-COATED CHROMITE SAND FOR RAPID SAND CASTING APPLICATIONS

2021 ◽  
Vol 32 (3) ◽  
pp. 290-298
Author(s):  
Neo Tshabalala ◽  
Kasongo Nyembwe ◽  
Malan Van Tonder
Keyword(s):  
Three Dimensional ◽  
Chemical Properties ◽  
Cost Effective ◽  
Sand Casting ◽  
Raw Material ◽  
Silica Sand ◽  
Three Dimensional Printing ◽  
Physical And Chemical ◽  
Dimensional Printing ◽  
And Chemical Properties

Applications of three-dimensional printing (3DP) to sand casting have been well-established in the last two decades. The preferred raw material is silica (quartz) sand, as it is the most readily available and cost effective sand. However, silica sand as a refractory material has some technical limitations, including high thermal linear expansion, low refractoriness, and thermal conductivity. Therefore, it is not suitable for all castings. Other refractory sand types are available, including chromite sand, which is abundantly available in South Africa. Analysis of the physical and chemical properties of in-laboratory coating of a locally available chromite sand was conducted through known metal foundry tests that provide an understanding of the quality and suitability of the use of chromite sand as a potential substitute for silica material for rapid sand-casting applications. The results of this study will inform the industry about the optimisation of parameters for the manufacturing of a resin-coated chromite sand and its use in additive manufacturing using a Voxeljet VX 1000 printer.

scholarly journals Synthesis and Conductivity Studies of Poly(Methyl Methacrylate) (PMMA) by Co-Polymerization and Blending with Polyaniline (PANi)

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1939
Author(s):  
Helyati Abu Hassan Shaari ◽  
Muhammad Mahyiddin Ramli ◽  
Mohd Nazim Mohtar ◽  
Norizah Abdul Rahman ◽  
Azizan Ahmad
Keyword(s):  
Methyl Methacrylate ◽  
Mechanical Stability ◽  
Chemical Properties ◽  
Cost Effective ◽  
Poly Methyl Methacrylate ◽  
Conducting Materials ◽  
Potential Applications ◽  
Polymerization Condition ◽  
Physical And Chemical ◽  
And Chemical Properties

Poly(methyl methacrylate) (PMMA) is a lightweight insulating polymer that possesses good mechanical stability. On the other hand, polyaniline (PANi) is one of the most favorable conducting materials to be used, as it is easily synthesized, cost-effective, and has good conductivity. However, most organic solvents have restricted potential applications due to poor mechanical properties and dispersibility. Compared to PANi, PMMA has more outstanding physical and chemical properties, such as good dimensional stability and better molecular interactions between the monomers. To date, many research studies have focused on incorporating PANi into PMMA. In this review, the properties and suitability of PANi as a conducting material are briefly reviewed. The major parts of this paper reviewed different approaches to incorporating PANi into PMMA, as well as evaluating the modifications to improve its conductivity. Finally, the polymerization condition to prepare PMMA/PANi copolymer to improve its conductivity is also discussed.

scholarly journals Current Progress in Cross-Linked Peptide Self-Assemblies

2020 ◽  
Vol 21 (20) ◽  
pp. 7577
Author(s):  
Noriyuki Uchida ◽  
Takahiro Muraoka
Keyword(s):  
Self Assembly ◽  
Three Dimensional ◽  
Chemical Properties ◽  
Water Soluble ◽  
Cross Linking ◽  
Physical And Chemical Properties ◽  
Cell Scaffold ◽  
Scaffold Materials ◽  
Physical And Chemical ◽  
And Chemical Properties

Peptide-based fibrous supramolecular assemblies represent an emerging class of biomaterials that can realize various bioactivities and structures. Recently, a variety of peptide fibers with attractive functions have been designed together with the discovery of many peptide-based self-assembly units. Cross-linking of the peptide fibers is a key strategy to improve the functions of these materials. The cross-linking of peptide fibers forming three-dimensional networks in a dispersion can lead to changes in physical and chemical properties. Hydrogelation is a typical change caused by cross-linking, which makes it applicable to biomaterials such as cell scaffold materials. Cross-linking methods, which have been conventionally developed using water-soluble covalent polymers, are also useful in supramolecular peptide fibers. In the case of peptide fibers, unique cross-linking strategies can be designed by taking advantage of the functions of amino acids. This review focuses on the current progress in the design of cross-linked peptide fibers and their applications.

Sugarcane Biochar for Agricultural Use Produced in Different Conditions of Pyrolysis

2019 ◽  
pp. 1-8
Author(s):  
Juliany Barbosa de Pinho ◽  
Aloisio Bianchini ◽  
Pedro Silvério Xavier Pereira ◽  
Letycia Cunha Nunes ◽  
Rodrigo Fernandes Daros ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Exchange Capacity ◽  
Raw Material ◽  
Physical And Chemical Properties ◽  
Oxidizing Atmosphere ◽  
Different Temperatures ◽  
Agricultural Use ◽  
Physical And Chemical ◽  
And Chemical Properties

From the pyrolysis process, biochar is a carbon rich and recalcitrant organic material with potential for long term carbon sequestration because of its aromatic structure. However, the physical and chemical properties of the biochar vary due to the diversity of raw material and the conditions of production. The present study aimed to evaluate the biochar from the sugarcane bagasse at different temperatures and under two conditions of pyrolysis. The biochar was produced at two final temperatures 200°C (1 hour); 250°C (1h) and 250°C (2h), with pyrolysis of an oxidizing and non-oxidizing atmosphere for both. PH, cation exchange capacity (CTC), carbon content (C), Nitrogen (N), hydrogen (H), H:C, C:N and ash ratios were evaluated. The contents of C, H, N and the atomic ratios H:C and C:N were higher in Biochar produced in a non-oxidizing atmosphere (BNO). However, the content of ash, pH and CTC were higher in Biochar produced in oxidizing atmospheres (BO). One can conclude the direct influence of the pyrolysis condition.

scholarly journals Technological Parameters of the Process of Producing Metallized Iron Concentrates from Poor Raw Material

2019 ◽  
Vol 8 (11) ◽  
pp. 600-603 ◽  
Keyword(s):  
Chemical Properties ◽  
Raw Material ◽  
Physical And Chemical Properties ◽  
Technological Parameters ◽  
Metallurgical Processing ◽  
Physical And Chemical ◽  
And Chemical Properties

In article the possibility of receiving the metallized concentrates from ferriferous ores with the low content of iron, for the purpose of preparation them to metallurgical processing is considered. It is shown that the following factors have significant effect on effectiveness of process of receiving the metallized concentrates: composition of ore, physical and chemical properties of ore, possibility of receiving pellets, type and consumption of reducer, etc.

scholarly journals Dendrimers: A New Race of Pharmaceutical Nanocarriers

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Pooja Mittal ◽  
Anjali Saharan ◽  
Ravinder Verma ◽  
Farag M. A. Altalbawy ◽  
Mohammed A. Alfaidi ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Chemical Properties ◽  
Biologically Active ◽  
Dimensional Structure ◽  
Synthesis Mechanism ◽  
Drug Conjugates ◽  
Wide Range ◽  
New Race ◽  
Physical And Chemical ◽  
And Chemical Properties

Dendrimers are nanosized, symmetrical molecules in which a small atom or group of atoms is surrounded by the symmetric branches known as dendrons. The structure of dendrimers possesses the greatest impact on their physical and chemical properties. They grow outwards from the core-shell which further reacts with monomers having one reactive or two dormant molecules. Dendrimers’ unique characteristics such as hyperbranching, well-defined spherical structure, and high compatibility with the biological systems are responsible for their wide range of applications including medical and biomedical areas. Particularly, the dendrimers’ three-dimensional structure can incorporate a wide variety of drugs to form biologically active drug conjugates. In this review, we focus on the synthesis, mechanism of drug encapsulations in dendrimers, and their wide applications in drug delivery.

scholarly journals Effect of Li, Na and K Modification of Alumina on its Physical and Chemical Properties and Water Adsorption Ability

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4212 ◽  
Author(s):  
Sergey Reshetnikov ◽  
Irina Kurzina ◽  
Alesia Livanova ◽  
Eugene Meshcheryakov ◽  
Lyubov Isupova
Keyword(s):  
Low Temperature ◽  
Water Adsorption ◽  
Chemical Properties ◽  
Raw Material ◽  
Physical And Chemical Properties ◽  
High Adsorption ◽  
Initial Sample ◽  
Adsorption Ability ◽  
Physical And Chemical ◽  
And Chemical Properties

The effect of alkali metal (Li, Na, K) incorporation on the morphology and water vapor uptake properties of mesoporous Al2O3 has been studied. The modification of the raw material, pseudoboehmite, represented a mixture of low-temperature phases (γ + η + χ)-Al2O3, and has been done at low-temperature that does not change the phase ratio. A decrease in specific surface values and an average pores size increase were observed as a result of the introduction of metal cations by impregnation and subsequent thermal treatment. The influence of the content of the modifying metal on the adsorption ability of the obtained samples in relation to water vapours has been studied. It has been established that alkaline modification Al2O3 with the lithium cations did not result in adsorption ability improvement, whereas samples that were modified with sodium or potassium in the amount of 1.2 weight % and 2.6 weight %, respectively, possess a higher equilibrium capacity (by ~40%), as compared to that of the initial sample (Al2O3), and a sufficiently high adsorption rate.

BIOMEDICAL APPLICATIONS OF ELECTROSPUN NANOFIBERS

2020 ◽  
Vol 27 (11) ◽  
pp. 2030001
Author(s):  
ZHANG YANCONG ◽  
DOU LINBO ◽  
MA NING ◽  
WU FUHUA ◽  
NIU JINCHENG
Keyword(s):  
Biomedical Applications ◽  
Three Dimensional ◽  
Chemical Properties ◽  
Electrospun Nanofibers ◽  
High Porosity ◽  
Nanofiber Diameter ◽  
Surface Microscopy ◽  
Different Shapes ◽  
Physical And Chemical ◽  
And Chemical Properties

Electrospun technology is a simple and flexible method for preparation of nanofiber materials with unique physical and chemical properties. The nanofiber diameter is adjustable from several nanometers to few microns during the preparation. Electrospun nanofiber materials are easy to be assembled into different shapes of three-dimensional structures. These materials exhibit high porosity and surface area and can simulate the network structures of collagen fibers in a natural extracellular matrix, thereby providing a growth microenvironment for tissue cells. Electrospun nanofibers therefore have extensive application prospects in the biomedicine field, including in aerospace, filtration, biomedical applications, and biotechnology. Nanotechnology has the potential to revolutionize many fields, such as surface microscopy, silicon fabrication, biochemistry, molecular biology, physical chemistry, and computational engineering, while the advent of nanofibers has increased the understanding of nanotechnology among academia, industry, and the general public. This paper mainly introduces the application of nanofiber materials in tissue engineering, drug release, wound dressing, and other biomedicine fields.

scholarly journals Pengaruh Proses Refining Minyak Bekas Sebagai Bahan Baku Biodiesel

2018 ◽  
Vol 11 (2) ◽  
pp. 72
Author(s):  
Ni Made Suaniti ◽  
I Wayan Bandem Adnyana
Keyword(s):  
Sulfuric Acid ◽  
Chemical Properties ◽  
Frying Oil ◽  
Raw Material ◽  
Infrared Analysis ◽  
Used Oil ◽  
Wave Numbers ◽  
Homogeneous Particle ◽  
Physical And Chemical ◽  
And Chemical Properties

Penampakan minyak bekas hasil penggorengan yang berwarna coklat gelap tidak baik dikonsumsi akibat sifat fisik dan kimia minyak berubah sehingga dapat dimanfaatkan sebagai bahan bakar atau biodiesel. Tujuan penelitian ini adalah menganalisis bahan baku minyak hasil penggorengan setelah direfining dengan asam sulfat dan biodiesel hasil proses transesterifikasi dengan CaO sebagai katalis heterogen. Metode yang digunakan adalah spektroskopi Infra merah dan pengukuran secara mikroskopik. Hasil refining minyak bekas dengan asam sulfat lebih jernih dan analisis secara Infra Merah menunjukkan bahwa terjadi penurunan serapan pada berbagai bilangan gelombang dibandingkan terhadap minyak bekas. Serapan terjadi pada bilangan gelombang 2900 cm-1 diduga adanya ikatan –CH3, -CH2-, -C-H; 1656 cm1 diduga adalah ikatan C=C dan C=O; 1300 cm-1 diduga ikatan–C-H; dan 3600 cm-1 diduga adanya ikatan O-H. Secara mikroskopik menunjukkan hasil dengan ukuran partikel semakin kecil dan lebih homogen. The appearance of dark brown frying oil that is used for frying is not well consumed due to the changing physical and chemical properties of the oil so that it can be used as fuel or biodiesel. The aim of this study was to analyze the raw material of frying oil after being refined with sulfuric acid and biodiesel from the transesterification process with CaO as a heterogeneous catalyst. The method used is infrared spectroscopy and microscopic measurements. The results of refining used oil with sulfuric acid became clear and infrared analysis showed that there was a decrease in absorption at various wave numbers compared to used oil. Absorption occurred at wave numbers 2900 cm-1 was suspected to have –CH3, -CH2-, C-H bonds; 1656 cm-1 was thought to be C=C and C=O bonds; 1300cm-1  was –C-H bond;  and 3600 cm-1 was suspected to be O-H bond. Microscopically shows the results with smaller and more homogeneous particle sizes.

scholarly journals Synthesis and Characterization of Porous CaCO3 Vaterite Particles by Simple Solution Method

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4425
Author(s):  
Renny Febrida ◽  
Arief Cahyanto ◽  
Ellyza Herda ◽  
Vanitha Muthukanan ◽  
Nina Djustiana ◽  
...  
Keyword(s):  
Reaction Time ◽  
Reaction Times ◽  
Chemical Properties ◽  
Raw Material ◽  
Porous Microsphere ◽  
Different Temperatures ◽  
Mixing Method ◽  
Physical And Chemical ◽  
And Chemical Properties

Appropriately engineered CaCO3 vaterite has interesting properties such as biodegradability, large surface area, and unique physical and chemical properties that allow a variety of uses in medical applications, mainly in dental material as the scaffold. In this paper, we report the synthesis of vaterite from Ca(NO3)2·4H2O without porogen to obtain a highly pure and porous microsphere for raw material of calcium phosphate as the scaffold in our future development. CaCO3 properties were investigated at two different temperatures (20 and 27 °C) and stirring speeds (800 and 1000 rpm) and at various reaction times (5, 10, 15, 30, and 60 min). The as-prepared porous CaCO3 powders were characterized by FTIR, XRD, SEM, TEM, and BET methods. The results showed that vaterite with purity 95.3%, crystallite size 23.91 nm, and porous microsphere with lowest pore diameter 3.5578 nm was obtained at reaction time 30 min, temperature reaction 20 °C, and stirring speed 800 rpm. It was emphasized that a more spherical microsphere with a smaller size and nanostructure contained multiple primary nanoparticles received at a lower stirring speed (800 rpm) at the reaction time of 30 min. One of the outstanding results of this study is the formation of the porous vaterite microsphere with a pore size of ~3.55 nm without any additional porogen or template by using a simple mixing method.

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