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A pine/co-PES composite (PCPES composite) was proposed as the feedstock for powder bed fusion (laser sintering, LS). This paper aims to provide some necessary experimental data and the theoretical foundation for LS of pine/co-PES, especially for the application of using the laser-sintered pine/co-PES parts as complex structural patterns in investment casting.

The PCPES composites with different pine loadings were mixed mechanically. The composite’s preheating temperature and processing temperature during LS were determined experimentally based on the material’s thermal behavior. The effects of pine powder on the binding mechanism of PCPES composites were discussed through analyzing the microstructure of the laser-sintered parts’. Mechanical properties and dimensional precision of laser-sintered PCPES parts in different pine loadings were tested, and the parts’ mechanical properties were strengthened by wax-infiltration post-processing. The influence extents of process parameters on the mechanical properties of laser-sintered 20 Wt.% pine/co-PES parts were investigated using a 1/2 fractional factorials experiment.

20 Wt.% pine/co-PES is considered to be a promising wood-plastic composite for laser sintering. The relationship between mechanical strength of its laser-sintered parts and process parameters was built up using mathematical formulas. Experimental results show density, tensile strength, flexural strength and surface roughness of laser-sintered 20 Wt.% pine/co-PES parts are improved by 72.7-75.0%, 21.9-111.3%, 26.8-86.2%, 27.0-29.1% after post-process infiltration with a wax. A promising application of the wax-infiltrated laser-sintered parts is for investment casting cores and patterns.

The proper process parameters and forming properties of laser-sintered parts are limited to the results of laser sintering experiments carried on using AFS 360 rapid prototyping device.

This investigation not only provides a new feedstock for laser sintering with the advantages of low cost and fabricability but also uses an advanced technique to produce personalized wood-plastic parts efficiently. Mathematical models between mechanical properties of laser-sintered PCPES parts and LS process parameters will guide the further LS experiments using the 20 Wt.% pine/co-PES composite. Besides, the laser-sintered PCPES parts after wax-infiltration post-processing are promising as complex structural patterns for use in investment casting.

The aim of the present paper to compare the cleaning treatments of paper samples exposed to artificial aging, toluene and isopropyl alcohol gel in cleaning wax stains.

In total, paper samples were made from wood pulp. They had a deterioration phenomenon represented in the stains of the paraffin wax, so two types of cleaning were used: A traditional method using a toluene solution and another new method using isopropanol gel by a cotton swap in a circular movement until the completion of the cleaning process. Then, all paper samples were treated with toluene and isopropanol to handle the second artificial aging and detect how the samples were affected by artificial aging. For identifying the efficacy of these materials in removing paraffin wax stains, a range of examinations and analyses were used, such as universal serial bus, scanning electron microscope, infrared analysis (IR), pH analysis, color change analysis. Moreover, these results were compared with the standard sample’s results.

The results of examinations and analyses proved that the use of toluene affected the paper samples. Their effects were twice as weak, fragile and degraded paper fibers compared to isopropanol gel. Therefore, the isopropanol gel is preferred for paper cleaning to the toluene solution.

This paper highlights the efficiency of isopropyl alcohol gel in cleaning wax stains from historical paper supports.

This paper aims to determine the regression rate using wax fuels for three different grain configurations and find a suitable grain port design for hybrid rocket application.

The design methodology of this work includes different grain port designs and subsequent selection of solid fuels for a suitable hybrid rocket application. A square, a cylindrical and a five-point star grained were designed and prepared using paraffin and beeswax fuels. They were tested in a laboratory-scale rocket with gaseous oxygen to study the effectiveness of solid fuels on these grain structures. The regression rate by static fire testing of these wax fuels was analyzed.

Beeswax performance is better than that of paraffin wax fuel for all three designs, and the five-slotted star fuel port grain attained the best performance. Beeswax fuel attained an average regression rate ≈of 1.35 mm/s as a function of oxidizer mass flux Gox ≈ 111.8 kg/m² s and for paraffin wax 1.199 mm/s at Gox ≈ 121 kg/m² s with gaseous oxygen. The local regression rates of fuels increased in the range of 0.93–1.194 mm/s at oxidizer mass flux range of 98–131 kg/m² s for cylindrical grain, 0.99–1.21 mm/s at oxidizer mass flux range of 96–129 kg/m2s for square grain and 1.12–1.35 mm/s at oxidizer mass flux range of 91–126 kg/m² s for a star grain. A complete set of the regression rate formulas is obtained for all three-grain designs as a function of oxidizer flux rate.

The experiment has been performed for a lower chamber pressure up to 10 bar.

Different grain configurations were designed according to the required dimension of the combustion chamber, injector and exhaust nozzle of the design of a lab-scale hybrid rocket, and input parameters were selected and analyzed.

SOLVENT DEWAXING OF LUBRICATING oils found its first commercial application in 1927 when Indian Refining Company started its original acetone‐benzene dewaxing operation. Since that time, solvent dewaxing has wholly superseded the classical cold pressing methods in new installations. Of 171,165 bbls/doz. lube oil produced in the United States in 1951, some 60% was of the solvent extraction type and 40% of the older conventional type. By 1954, solvent extraction's share had risen to an estimated 75% of all dewaxing operations.

The purpose of this study is to investigate the physical, chemical and thermal characteristics of paraffin-blended fuels to determine their suitability as fuel in hybrid rockets.

Wax fuels are viable and efficient alternatives to conventional rocket fuels, having excellent structural strength and thermal and mechanical properties. The authors report a study of the morphological, chemical and thermal properties of paraffin wax with and without additives for use as fuels in hybrid rockets. Scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy were used for the morphological and chemical characterizations of the fuel blends. The thermal stability and combustion characteristics were assessed under an atmosphere of nitrogen by the simultaneous application of thermogravimetry and differential scanning calorimetry techniques.

The melting temperatures for pure paraffin and other formulations were around 61°C as seen in differential scanning calorimetry experiments. Variations in the compositions of monoesters, n-alkanes, fatty acids, carboxylic acids methyl and hydroxyl esters in the fuel samples were assessed using Fourier transform infrared spectroscopy. The assessment criterion was chosen as the relative content of carbonyl groups, and the ratio of the stretching vibration of the C–C bonds to the deformation vibration of the aliphatic carbon–hydrogen bonds was taken as the basis for the quantitative calibration. The crystal phases identified by X-ray diffraction were used to identify nonlinear chemicals and alkane lengths. Scanning electron microscopy validated homogeneity in the paraffin-blended samples.

This study presents the thermal stability and other relevant characteristics of fuel formulations comprising unconventional blends.

In the first article in this series, the author dealt with general classification and composition of oils, fats and waxes, and this went on to discuss the properties of drying and non‐drying vegetable oils. In this second part, the properties of animal and fish oils, fats and waxes will be considered.

The use of removable complete dentures is a selectable restorative procedure for edentulous patients. To improve the fabrication quality and efficiency of removable complete dentures, this paper aims to introduce a new method to fabricate customized wax complete dentures with additive manufacturing. This process uses complementary digital technologies, and allows faster and better manufacture of complete dentures.

In the study, a dental scanner was used to obtain surface data from edentulous casts and rims made by the dentist. A parameterized three-dimensional graphic database of artificial teeth was pre-established. Specialized computer-aided design software was used to set up the artificial dentition and design the esthetic gingiva and base plate. A selective laser sintering machine was used to transfer the data from stereolithography files into a wax base plate with location holes for each artificial tooth.

Under this method, a set of wax base plates with 28 location holes available for the placement of the artificial teeth were designed and fabricated within 6 h. The try-in wax dentures fitted the patient’s mouth well, besides occlusion relationships. Then, the occlusion relationships can be adjusted manually to achieve a balanced centric occlusion.

This method can be used to design and fabricate wax try-in removable complete dentures semi-automatically and rapidly; however, the algorithm for the occlusion contact design needs to be improved.

The purpose of this paper is to present the advantages of computer-aided design/rapid prototyping (CAD/RP) usage in designing and manufacturing of the core models used for precise casting with direct and single solidification of aircraft engine turbine blade cores.

The process of modelling three-dimensional CAD geometry of research blade in relation to the model of the core was presented with different wax types used in the RP technique.

The geometry of the blade model has been designed in a way which allows making a silicon mould on the basis of a base prototype in the process of rapid tooling (RP/RT). Filing by different wax types was investigated in mean of the impact on filling accuracy of the mould cavity.

The resulting models were used to make ceramic moulds and carry further work on the development of casting technology in the process of directional solidification and single crystal solidification of core blades of aircraft engines.

The authors describe two new products of the Czechoslovak chemical industry and their properties, namely KRNB conservation wax and paper with SVIK vaporising inhibitor. Both materials have been developed at the State Research institute for the Protection of Material, have been thoroughly tested, and are now in production. Instructions are given for the use of both media, and an indication is given of the sphere of applications, in which they have advantages over all other present methods of temporary protection of metal products.

THE author believes that at the time of presenting this paper there does not exist in Great Britain a company who will produce steel or high melting point non‐ferrous alloy castings by the Lost Wax Process on a commercial basis to the trade.