scholarly journals Alumina, Zirconia and Their Composite Ceramics with Properties Tailored for Medical Applications

2021 ◽  
Vol 5 (11) ◽  
pp. 306
Author(s):  
Wolfgang Burger ◽  
Gundula Kiefer
Keyword(s):  
Fracture Toughness ◽  
Composite Materials ◽  
Raw Materials ◽  
Tetragonal Zirconia ◽  
Raw Material ◽  
Medical Applications ◽  
Standard Material ◽  
Long Time ◽  
Metastable Tetragonal Zirconia ◽  
Dental Applications

Although in 1977 the first ceramic composite material had been introduced into the market, it was a long time before composite materials were qualified for medical applications. For a long period high purity alumina ceramics have been used as ball-heads and cups. Because of their brittleness, in 1986 yttria stabilized zirconia has been introduced into this application, because of higher strength and fracture toughness. However, due to its hydrothermal instability this material disappeared in orthopaedic applications in 2000. Meanwhile a composite materials based on an alumina matrix with dispersed metastable tetragonal zirconia particles and in-situ formed hexagonal platelets became the standard material for ceramic ball-heads, because of their excellent mechanical strength, hardness and improved fracture toughness. Especially fracture toughness can be improved further by special material formulations and tailored microstructure. It has been shown that a mixed stabilisation of zirconia by yttria and ceria with dispersed alumina and hexagonal platelets overcomes the hydrothermal instability and excellent materials properties can be achieved. Such materials do have big potential to be used in dental applications. Furthermore, these materials also can be seen as a new generation for ball-heads, because of their enhanced fracture toughness. All materials are described within these articles. In order to achieve the required properties of the materials, special raw materials are required. Therefore, it is quite important to understand and know the raw material manufacturing procedures.

scholarly journals TECHNICAL AND TECHNOLOGICAL SOLUTIONS FOR PREPARING FLAX RAW MATERIALS FOR PROCESSING

2021 ◽  
pp. 227-237
Author(s):  
Yu. Вerezovsky ◽  
T. Kuzmina ◽  
M. Yedynovych ◽  
G. Boyko ◽  
N. Lyalina ◽  
...  
Keyword(s):  
Raw Materials ◽  
Hollow Structure ◽  
Weather Conditions ◽  
Raw Material ◽  
Hollow Structures ◽  
Adverse Weather Conditions ◽  
Adverse Weather ◽  
Long Time ◽  
Experimental Researches

The article contains theoretical and experimental researches in the field of the preservation of flax raw material of high moisture content. In the article, factors that are worsening the quality of flax raw material, resulting in non-observance of agrotechnical and technological requirements of preparing, collecting, harvesting the stem material, adverse weather conditions and other factors, are considered. The objective of this paper is to study the influence of preservation agents’ concentrations and of hollow structure device on the quality of flax raw material during long-time storage. In the article, the influence of aqueous preservatives’ concentration, humidity, storage length on the quality of fibrous products, obtained as a result of processing stem material, is analyzed. The influence of the device of hollow structures, as an alternative to preservatives, on the storage process of bast crops stem material was evaluated. The method of flax retted straw storage is described, actions of the main factors influence on the strength of fibers are analyzed. It is demonstrated, that prolongation of flax raw material preservation time can be made by using preservatives without considerable wastes of quality.

scholarly journals Upaya Pengolahan Limbah Kotoran Babi Menggunakan Komposter Rumah Tangga

2018 ◽  
Vol 12 (2) ◽  
pp. 104
Author(s):  
Widya Sari ◽  
I Wayan Budiarsa Suyasa ◽  
I.G.B Sila Dharma
Keyword(s):  
Organic Materials ◽  
Raw Materials ◽  
Raw Material ◽  
Pig Manure ◽  
Vegetable Waste ◽  
Composting Process ◽  
Experiment Method ◽  
Long Time ◽  
Speed Up ◽  
Macro Nutrients

ABSTRACT        The production of pig manure waste potentially pollutes the soil, water and air. One of the most effective processing a waste treatments is through composting. The composting process takes a long time if not assisted by the activator as decomposers of organic materials in order to accelerate the composting process. Activators such as local microorganism (MOL) contain macro nutrients, micro and active microorganism that potentially decomposed organic materials, growth stimulants and pest/disease control agents such as to help speed up the composting process. This study aims to determine the C/N ratio of optimal raw materials for composting of pig manure and vegetable waste, determining the effect of adding local microorganism (MOL) to the length of time of composting and determining the effectiveness of business from composting of pig manure and vegetable waste based on the calculation of B/C ratio.        This research uses quantitative approach with experiment method. The first stage is the preparation of the raw material which is divided into three groups : composition 1 with 75% (pig manure) and 25% (vegetable waste), composition 2 with 50% (pig manure) and 50% (vegetable waste) and then composition 3 with 25% (pig manure) and 75% (vegetable waste). Furthermore, the best raw material composition was treated with variations of MOL addition of A (100 ml), B (300 ml), C (500 ml) and D (without MOL).        The results showed that the composition of the best raw material mixture was a mixture composition of 25% (pig manure) and 75% (vegetable waste) with a C/N ratio of 38.95. The effect of MOL addition indicates that the greater MOL volume the faster to composting process. The quality compost with addition of MOL has C/N ratio levels is (16,30), N-total (1,65%), P tersedia (8043,02 ppm), K tersedia (8857,40 ppm), Fe (1,87%), Mn (0,09%) Zn (480 ppm) in which that value meets the SNI 19-7030-2004. Based on analysis of B/C ratio obtained result of 1.04 where the value is approaching criteria B/C ratio more than 1.00 which means compost business feasible to be developed.   Keywords : Pig manure, MOL, time of composting, composter, B/C ratio

Low Temperature Degradation of Y-TZP Ceramic for Dental Applications

2013 ◽  
Vol 873 ◽  
pp. 241-249
Author(s):  
Zhi Kai Wu ◽  
Ning Li ◽  
Wan Qian Zhao ◽  
Jia Zhen Yan
Keyword(s):  
Low Temperature ◽  
Substantial Reduction ◽  
Tetragonal Zirconia ◽  
Ceramic Materials ◽  
Dental Ceramics ◽  
All Ceramic ◽  
Long Time ◽  
Core Thickness ◽  
Dental Applications

Yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic has been recently introduced into prosthetic dentistry for the fabrication of crowns and fixed partial dentures (FPDs). The mechanical properties of Y-TZP are the highest ever reported for the all-ceramic materials. This is favorable for the fabrication of multi-unit posterior bridges and the substantial reduction in core thickness. However, Y-TZP ceramic is susceptible to low temperature degradation (LTD), which is detrimental to the long-time survival and aesthetics of zirconia restorations in vivo. This review summarizes the characterization, mechanisms, and influencing factors of the LTD in dental Y-TZP ceramic. In addition, the recent trend of exploring high aging resistant zirconia-based dental ceramics is discussed.

The Development of Composite Building Product and its Fire Technical Characteristics

2014 ◽  
Vol 1001 ◽  
pp. 368-372
Author(s):  
Miroslava Netopilová ◽  
Jan Mikulenka ◽  
Anna Benešová
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Industrial Waste ◽  
Raw Materials ◽  
Raw Material ◽  
Waste Materials ◽  
Building Industry ◽  
Building Product ◽  
Material Resources ◽  
Renewable Raw Material

The article focuses on the research and development of a new composite material applicable in building industry, renewable raw material resources and industrial waste materials. The aim of the research is not only the application of concrete secondary raw materials but also the gaining of required safety aspects of these composite materials, i.e. certain fire technical characteristics.

Fracture Toughness of Samarium Cobalt Magnets

2015 ◽  
Author(s):  
Paul R. Curtin ◽  
Steve Constantinides ◽  
Patricia Iglesias Victoria
Keyword(s):  
Fracture Toughness ◽  
Grain Size ◽  
Rare Earth ◽  
Crack Propagation ◽  
Grain Boundaries ◽  
Permanent Magnets ◽  
Raw Material ◽  
High Coercivity ◽  
Standard Material ◽  
Average Grain Size

Samarium Cobalt (SmCo) magnets have been the magnet of choice for a variety of industries for many years due to their favorable magnetic properties. Their high coercivity, combined with a low temperature coefficient, make them the ideal permanent magnet for demanding high temperature applications. One of the biggest concerns with rare earth magnets is their brittleness. Samarium Cobalt magnets in particular are prone to fracturing during machining and assembly. In manufacturing, great care must be taken to avoid chipping or fracturing these magnets due to their brittle nature. There are two main grades of Samarium Cobalt magnets, 1:5 and 2:17. These ratios define the nominal ratio of rare earth to transition metal content. In this paper, an investigation is performed on the fracture toughness of permanent magnets based on the Samarium Cobalt 2:17 composition. Various techniques are used to characterize the microstructure of the material, and quantify the material properties. Optical microscopy is used to characterize the grain structure of the material and quantify the porosity of the material after sintering. By comparing the average grain size and fracture toughness of several samples, grain size was shown to not affect fracture toughness in standard material. Latent cracks in defective material showed no preference to follow grain boundaries, oxides inclusions or voids. River marks in fracture surfaces are seen through scanning electron microscopy, confirming the transgranular cracking pattern seen by Li et al [1]This suggests that the toughness of the material is an inherent property of the main phase, not of grain boundaries or contaminants. Samarium Cobalt magnets exhibit both mechanical and magnetic anisotropy due to the alignment of their crystal structure in the manufacturing process. Using Palmqvist indentation crack techniques, the magnetic orientation of the grains was seen to greatly influence the direction of crack propagation from the tip of the indenter. Measurements of fracture toughness using this technique produce highly scattered data due to this anisotropic nature of the material. Specimens loaded with the indenter axis parallel to the direction of orientation show normal Palmqvist cracks, while specimens loaded perpendicular to the direction of magnetization exhibit crack propagation initiating from the faces of the indenter. To better quantify the material’s brittleness, fracture testing is performed on specially prepared samples to obtain an absolute measure of fracture toughness (K1c). Results show that SmCo is measurably weaker than other magnetic materials such as neodymium iron boron magnets[2]. Furthermore, neither relative concentration of Samarium nor source of raw material show notable effect on the fracture toughness of the material.

scholarly journals Mechanical properties of lithic raw materials from Kazakhstan: comparing chert, shale, and porphyry

2021 ◽  
Author(s):  
Abay Namen ◽  
Radu Iovita ◽  
Klaus G. Nickel ◽  
Aristeidis Varis ◽  
Zhaken Taimagambetov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Fracture Resistance ◽  
Material Selection ◽  
Raw Materials ◽  
Mineralogical Composition ◽  
Raw Material ◽  
Indentation Fracture ◽  
Material Quality ◽  
Lithic Raw Material

The study of lithic raw material quality has become one of the major interpretive tools to investigate the raw material selection behaviour and its influence to the knapping technology. In order to make objective assessments of raw material quality, their mechanical properties (e.g., fracture resistance, hardness, modulus of elasticity) should be measured. However, such comprehensive investigations are lacking for the Palaeolithic of Kazakhstan. In this work, we investigate geological and archaeological lithic raw material samples of chert, porphyry, and shale collected from the Inner Asian Mountain Corridor (henceforth IAMC). Selected samples of aforementioned rocks were tested by means of Vickers and Knoop indentation methods to determine one aspect of their mechanical properties: their indentation fracture resistance (a value closely related to fracture toughness). These tests were complemented by traditional petrographic studies to characterise the mineralogical composition and evaluate the level of impurities that could have potentially affected the mechanical properties. The results show that materials, such as porphyry, previously thought to be of lower quality due to the anisotropic composition and coarse feldspar and quartz phenocrysts embedded in a silica rich matrix, possess fracture toughness values that can be compared to those of chert. Thus, it appears that different raw materials cannot be distinguished from the point of view of indentation fracture resistance, calling for detailed supplementary analyses of different fracture properties. This work also offers first insight into the quality of archaeological porphyry that was utilised as a primary raw material at various Middle and Upper Palaeolithic sites in the IAMC.

scholarly journals Penentuan Kelayakan Jagung Biji Untuk Pakan Ternak Dengan Metode Fuzzy Saw

JURTEKSI ◽  
2017 ◽  
Vol 4 (1) ◽  
pp. 79-84
Author(s):  
Widiarti Rista Maya ◽  
Ahmad Fitri Boy
Keyword(s):  
Decision Making ◽  
Decision Support ◽  
Decision Support System ◽  
Support System ◽  
Raw Materials ◽  
Raw Material ◽  
Decision Making Process ◽  
Weighting Method ◽  
Long Time ◽  
Simple Additive Weighting

Abstract: In the decision making process of the feasibility of corn raw materials so far only see the physical raw materials tend to be subjective so that in the decision making process of the feasibilityof corn raw materials must take a long time , sometimes the decision taken is not appropriate so that this needs to be addressed again for the feasibility of corn raw materials. From the description above need to be made an auxiliary program for decision support system by using fuzzy SAW ( Simple Additive Weighting ) method in determining corn raw material that is acceptable to PT. Charoen Phokpand Indonesia. Program which will be made more to assist manager or staff in taking decision and not replace it. The results of this study are expected to assist managers or staff in making decisions for the process of assessing the feasibility of corn raw materials in PT. Charoen Phokpand Indonesia so as to improve the quality of human resources. Keywords: corn raw materials, decision support system, fuzzy saw method Abstrak: Dalam proses pengambilan keputusan kelayakan bahan baku jagung selama ini hanya melihat fisik bahan baku yang cenderung subjektif sehingga dalam proses pengambilan keputusan kelayakan bahan baku jagung harus membutuhkan waktu yang cukup lama, terkadang keputusan yang diambil tidak tepat sehingga hal ini perlu dibenahi lagi untuk proses pengambilan keputusan kelayakan bahan baku jagung. Dari uraian diatas perlu dibuat suatu program bantu untuk sistem pendukung keputusan dengan menggunakan metode fuzzy SAW (Simple Additeve Weighting) dalam menentukan bahan baku jagung yang layak diterima pada PT. Charoen Phokpand Indonesia. Program yang akan dibuat lebih bersifat untuk membantu manager atau staff dalam pengambilan keputusan dan bukan menggantikannya. Hasil dari penelitian ini diharapkan dapat membantu manager atau staff dalam mengambil keputusan untuk proses penilaian kelayakan bahan baku jagung pada PT. Charoen Phokpand Indonesia sehingga dapat meningkatkan kualitas sumber daya manusia. Kata kunci: Bahan baku jagung, Sistem Pendukung Keputusan, metode fuzzy SAW

scholarly journals IMPROVING THE METHOD OF QUANTITATIVE DETERMINATION OF THE AMOUNT OF CAROTENOIDS IN THE RAW MATERIAL “ROSEHIP FRUIT”

2020 ◽  
pp. 131-138
Author(s):  
Vladimir Aleksandrovich Kurkin ◽  
Ol'ga Vladimirovna Sharova ◽  
Polina Valeriyevna Afanaseva
Keyword(s):  
Ascorbic Acid ◽  
Quantitative Determination ◽  
Raw Materials ◽  
Water Soluble ◽  
Biologically Active ◽  
Raw Material ◽  
Test Quality ◽  
Total Carotenoids ◽  
Long Time

The fruits of wild rose (Fructus Rosae) have been widely used in both traditional and officinal medicine for the long time. The pharmacological effect of the Rosehip medicine is related to the content of such biologically active compounds as: water-soluble (ascorbic acid) and fat-soluble (carotenoids) vitamins, as well as flavonoids (astragalin, isoquercitrin, tiliroside). Such medicine as Holosas, Carotolin and Rosehip syrup are obtained from the fruits of this plant. In addition, wild rose fruits are part of the various fees from which patients could prepare water infusions at home themselves. Regulatory documentation provides for the analysis of Rosehip raw materials three parameters: the content of ascorbic acid, the total carotenoids and flavonoids. The quantitative content of the total carotenoids in the fruits of the rosehip is regulated for the production of rosehip oil and Carotolin. However, in our opinion, the method of quantitative determination of the total carotenoids, described in the State Pharmacopoeia of the Russian Federation of the XIV edition, is too complicated and contains an unreasonably entered coefficient in the formula, leading to an overestimation of the analysis results in 10 times. We have developed the methodic of quantitative determination of the total carotenoids in Rosehip, that include single extraction of raw materials with hexane at room temperature and periodic mixing in the ratio of «raw material : extract» 1 : 30. Investigated solution there was obtained by diluting the hexane extract in the ratio of 2:25 and measured the optical density at wavelength 450 nm. Adjustments have been made to the formula for the calculating of the total carotenoids relating to the removal of the coefficient 10 unjustifiably entered into the pharmacopoeial methodic. It was determined that the content of the total carotenoids calculated on ß-carotene varied from 10.15 to 74.5 mg%. The metrological characteristics of the methodic indicate that the error of a single determination of the total carotenoids in the rosehip fruits with a 95% confidence level is ± 3.57%. Based on the results of the studies, a new test quality indicators “content of the total carotenoids at least 30 mg%” was substantiated instead of 300 mg%.

scholarly journals The Effect of Activator Addition to the Compost with Biopore Infiltration Hole (BIH) Method

2021 ◽  
Vol 19 (1) ◽  
pp. 53-59
Author(s):  
Yenni Ruslinda ◽  
Rizki Aziz ◽  
Larasati Sekar Arum ◽  
Novita Sari
Keyword(s):  
Food Waste ◽  
Organic Waste ◽  
Raw Materials ◽  
Infiltration Rate ◽  
Raw Material ◽  
Water Infiltration ◽  
Yard Waste ◽  
Macro Elements ◽  
Long Time

The composition of organic waste reaches 59% of the total municipal solid waste in Indonesia. One way to process organic waste is composting by utilizing microorganisms to break down waste into compost. Naturally, the composting process took a long time but can be accelerated by adding microorganisms to the activator. This study analyzes the quality and quantity of compost using the Biopore Infiltration Hole (BIH) method with activator addition. Composting was duplicated in the yard area with clay soil type and water infiltration rate of 0,3 cm/hour. The BIH was made in a 10 cm diameter, a 100 cm depth, and the distance between the holes was 50 cm. Composting variations consist of variations in the composition of the raw materials and the activators' uses. Variations in the raw material composition consisted of 100% yard waste, 100% food waste, 50% yard waste and 50% food waste, and 70% food waste and 30% yard waste. In contrast, the activator variations consisted of no activator, EM4 activator, and Stardec activator. Compost analysis consists of maturity, quality of physical and macro elements, and quantity of compost. The results showed that all variations of composting had met the standard of maturity and quality of physical and macro elements according to SNI 19-7030-2004. The addition of activator affected composting time and compost quantity. The composting time in BIH with activator ranges from 41-60 days. In BIH without activator ranges from 65-75 days, there was a reduction in composting time by 15-25 days with the activator addition. However, the activator addition caused reducing the compost quantity by 10-20%. The selection of compost variations by scoring results in compost with a composition of 50% yard waste and 50% food waste and the addition of Stardec activators was the best variation in terms of compost maturity, quality, and quantity.

scholarly journals The potential for developing local corn from East Nusa Tenggara as raw material for indigenous cuisine and processed products: A mini-review

2021 ◽  
Vol 924 (1) ◽  
pp. 012039
Author(s):  
A Hamaisa ◽  
T Estiasih ◽  
W D R Putri ◽  
K Fibrianto
Keyword(s):  
Raw Materials ◽  
Cooking Time ◽  
Raw Material ◽  
Staple Food ◽  
Local Varieties ◽  
Starch Modification ◽  
Long Time ◽  
Processed Products ◽  
High Amylose ◽  
Cooking Times

Abstract East Nusa Tenggara is one of the provinces in Indonesia that uses corn as staple food. Bose corn is an indigenous cuisine for people on the island of Timor, East Nusa Tenggara province. The corn used as raw material for this indigenous cuisine is generally local varieties. Local varieties of corn contain high amylose, so it takes a long time to cook. Starch modification is an instantization method which can be used to shorten its cooking time. Nixtamalization and pregelatinization are simple starch modification methods that can be applied by the community using a certain level of calcium hydroxide and appropriate cooking times. Bose corn is one of the indigenous cuisine processing products using local raw materials that can be developed as an instant food.

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