Assessment of Clay Deposits Quality from East of Erbil, Kurdistan Region, Iraq for some Ceramic Industries

For the assessment of clay deposits for brick manufacturing, seven clay samples from different locations were collected by channel sampling method from Injana, Mukdadiyah, Bai Hassan formations and Quaternary deposits in Bestana village, the study area is located east of Erbil city (NE Iraq). For ceramic manufacturing, the quality of clay should be measured according to some physical properties. The mineralogical and geochemical study revealed by using X-ray diffraction and chemical characteristics, which represented that all clay samples containing; kaolinite, smectite, illite, and chlorite with some mixed clay and non-clay mineral quartz, calcite, dolomite, and feldspar. The physical properties of clay samples including grain size analysis and Atterberg limits showed that the raw materials contain clay in high proportion, silt in medium proportion, and sand in minor proportion. Plasticity index of the studied samples showed that they are moderately plastic to plastic range. The geochemical analysis of the studied samples showed that the clay raw materials are composed mainly of silica and alumina, which act as refractory material in the ceramic industry. In addition to that, there are different proportions of calcium, iron oxides, magnesium, potassium, and sodium, which are flux oxides.

A Study of Thermal Stability of Hydroxyapatite

High-temperature powder sintering is an integral part of the dense ceramic manufacturing process. In order to find the optimal conditions for producing a ceramic product, the information about its behavior at high temperatures is required. However, the data available in the literature are very contradictory. In this work, the thermal stability of hydroxyapatite prepared by a solid-state mechanochemical method and structural changes occurring during sintering were studied. Stoichiometric hydroxyapatite was found to remain as a single-phase apatite structure with the space group P63/m up to 1300 °C inclusively. A further increase in the sintering temperature leads to its partial decomposition, a decrease in the crystallite size of the apatite phase, and the appearance of significant structural strains. It was shown that small deviations from stoichiometry in the Ca/P ratio upward or downward during the hydroxyapatite synthesis lead to a significant decrease in the thermal stability of hydroxyapatite. An apatite containing almost no hydroxyl groups, which is close to the composition of oxyapatite, was prepared. It was shown that the congruent melting of stoichiometric hydroxyapatite upon slow heating in a high-temperature furnace does not occur. At the same time, the fast heating of hydroxyapatite by laser radiation allows, under certain conditions, its congruent melting with the formation of a recrystallized monolayer of oxyhydroxyapatite. The data obtained in this study can be used when choosing sintering conditions to produce hydroxyapatite-based ceramics.

Inspiration from the History of Chinese and Hungarian Building Ceramics Manufacturing Technology to Industrial Smoke Control

Chinese and Hungarian architectural ceramics manufacturing technology is of the same origin, and both have certain influence in the world. In particular, Zsolnay, a Hungarian architectural ceramics brand, has made breakthroughs and innovations in the production process of products in the inheritance of more than 100 years, forming a unique architectural ceramics manufacturing technology. It can effectively reduce the concentration of flue gas particulate matter and sulfur dioxide produced in production. The historical experience of the development of building ceramic manufacturing technology in China and Hungary is of enlightenment to the current industrial smoke control.

Determination of Optimal Process Parameters In The Process Of Making Ceramics To Maximize Flexural Strength Using the Taguchi Method (Case Study at the Kasongan Ceramics UKM Center, Bantul, DIY)

Kasongan Ceramic UKM Center is an association of UKM which makes goods made from clay. Kasongan Ceramic UKM Center, located in Bantul Regency, DIY. The problem that is often experienced by Kasongan Ceramics Center is that products that are often cracked, warped, and easily brittle. The total production of Kasongan UKM Center from September 2019 to February 2020 was 32,256 units, with the number of defective products amounting to 3,873 or 12% of the total production. Based on the studies that have been done, it can be concluded that the defects of cracks, curling, and brittleness that occur are one of them caused by the less than optimal flexural strength of the ceramic products produced. To maximize the flexural strength of the ceramic products produced, the optimal ceramic manufacturing process parameters will be determined using the Taguchi method. To maximize the flexural strength in the process of making ceramics using the Taguchi method, it is necessary to do an experimental design. The first thing to do is to determine the controlled factors and levels in the ceramic manufacturing process that affect the flexural strength. After that determine a suitable orthogonal array and perform experiments based on the specified orthogonal array. The experimental results will be tested for its flexural strength in the laboratory. The resulting flexural strength data will be processed to determine the optimal ceramic manufacturing process parameters that maximize the bending strength of ceramics. Based on the data processing carried out, it is found that the optimal ceramic-making process parameters at the Kasongan Ceramics UKM Center that maximize flexural strength are the composition of 3 parts Godean clay, 3 parts Kasongan clay composition, 1 part sand composition, and burning using an open tub.

Applying Mixture of Municipal Incinerator Bottom Ash and Sewage Sludge Ash for Ceramic Manufacturing

Two secondary waste materials, municipal incinerator bottom ash (MIBA) and sewage sludge ash (SSA), were mixed with clay for ceramic manufacturing in this study. Specimens with 5 different MIBA replacement amount of 0%, 5%,10%, 15%, and 20%(wt) and 3 different SSA replacement amount of 0%, 10%, and 20%(wt) were prepared and then a series of tests and analysis were conducted to investigate how the two materials affect the quality of the final product and to what extent. It concludes that a mix with up to 20% of SSA and 5% of MIBA could result in quality tiles complying with specifications for interior or exterior flooring applications at certain kiln temperatures.

Accounting fraud before codification: An inquiry on budget misstatements in eighteenth-century Venice

The article focuses on the understudied role of accounting information in financial fraud in pre-modern historical contexts where specific regulations and standards were absent. Following a systematic literature review, the authors adopt an enriched version of the ‘fraud triangle’ to correctly identify fraud in such a setting. A microhistorical approach allows them to identify an exceptional case documenting the use of accounting statements to disclose a financial fraud in a ceramic manufacturing partnership in late eighteenth-century Venice. The case is analysed to identify the role of accounting information in determining the purpose (incentive), the technical possibility (opportunity) and the consequences (rationalisation) of the fraud. The results emphasise the authorities’ use of accounting statements to assess the situation of the company and fix its crisis, rather than to sanction fraudulent behaviours.

The Role of Solvents in Lithography-Based Ceramic Manufacturing of Lithium Disilicate

Digital dentistry is increasingly replacing conventional methods of manually producing dental restorations. With regards to computer-aided manufacturing (CAM), milling is state of the art. Additive manufacturing (AM), as a complementary approach, has also found its way into dental practices and laboratories. Vat photo-polymerization is gaining increasing attention, because it enables the production of full ceramic restorations with high precision. One of the two predominantly used ceramic materials for these applications is lithium disilicate, Li2Si2O5. This glass ceramic exhibits a substantial fracture toughness, although possesses much lower bending strength, than the other predominantly used ceramic material, zirconia. Additionally, it shows a much more natural optical appearance, due to its inherent translucency, and therefore is considered for anterior tooth restorations. In this work, an optimized formulation for photo-reactive lithium disilicate suspensions, to be processed by vat photo-polymerization, is presented. Following the fundamental theoretical considerations regarding this processing technique, a variety of solvents was used to adjust the main properties of the suspension. It is shown that this solvent approach is a useful tool to effectively optimize a suspension with regards to refractive index, rheology, and debinding behavior. Additionally, by examining the effect of the absorber, the exposure time could be reduced by a factor of ten.