Optimum cutting speed of block-cutting machines in natural stones for energy saving

Energy consumption of block-cutting machines represents a major cost item in the processing of travertines and other natural stones. Therefore, determining the optimum sawing conditions for a particular stone is of major importance in the natural stone-processing industry. An experimental study was carried out utilizing a fully instrumented block-cutter to investigate the sawing performances of five different types of travertine blocks during cutting with a circular diamond saw. The sawing tests were performed in the down-cutting mode. Performance measurements were determined by measuring the cutting speed and energy consumption. Then, specific energy was determined. The one main cutting parameter, cutting speed, was varied in the investigation of optimum cutting performance. Furthermore, some physico-mechanical properties of file travertine blocks were determined in the laboratory. As a result, it is found that the energy consumption （specific energy） of block cutting machines is highly affected by cutting speed. It is determined that specific energy value usually decreases when cutting speed increases. When the cutting speed is higher than the determined value, the diamond saw can become stuck in the travertine block; this situation can be a problem for the block-cutting machine. As a result, the optimum cutting speed obtained for the travertine mines examined is approximately 1.5-2.0 m/min.

Petrographic and geochemical analyses to characterise the source of built historical natural stones—a case study of the volcanic stones from historical quarries and Baoguosi Temple in the city of Ningbo,China

Characterising and sourcing natural stones are essential for not only understanding the historical information carried by heritage buildings and cultural heritage sites,but also providing necessary data for restoration and conservations.Petrographic analyses by polarised microscopy,along with the integrated chemical data acquired by inductively coupled plasma-mass spectrometry(ICP-MS)and X-ray difraction(XRD)analysis,allowed us to ascertain the compositions of stone materials.In this paper it is applied on samples collected from quarries of“three famous stones(Meiyuanshi-,Xiaoxishi-,and Dayinshi-stone)”in Ningbo and from the Sumeru platform in the main hall of Baoguosi Temple(Ningbo,Zhejiang,China).Comparison of petrographic features,major and trace elements of the stones studied indicated that they are all tufs but of diferent characteristics and origin.Moreover,we were able to confrm that the Sumeru platform in Baoguosi is made of Meiyuanshi-stone.The results have demonstrated the suitability of the approach and present a practicable solution for other stone buildings.

Effect of Lateritic Stone Aggregate and Coconut Husk Fiber on the Properties of Concrete

Natural stone aggregate forms the bulk volume of concrete and has contributed to the increased cost of concrete production. This has led to the search for alternate aggregates such as lateritic stone for concrete production. This paper investigates the engineering properties of concrete produced with lateritic aggregate (LA) as the coarse aggregate replacement and coconut husk fibre (CHF) as reinforcement. Natural stone aggregate was replaced by LA at 0%, 10%, 20%, 30%, 40%, and 50%, with 0.25% constant CHF by weight. A mix proportion of 1:1.5:3 with a water-cement ratio of 0.6 was used for producing concrete. A total of 162 specimens (90 cubes and 72 beams) were prepared and tested at the 7, 14, 21, and 28 days of curing. The highest compressive strength was 43.36 N/mm2 (10% LA replacement) as compared to the control of 41.51 N/mm2. The 10% LA replacement obtained the highest flexural strength of 5.35 N/mm2 as compared with the 5.29 N/mm2 for the control. The water absorption of the concrete increased from 2.8% (control) to 3.57% (50% replacement LA). Scanning electron microscopy (SEM) revealed micro gaps between CHF and LA concrete. The study, therefore, concludes that the use of LA and CHF positively influenced the strength properties of concrete. 10% LA replacement of coarse aggregate and 0.25% CHF is recommended to practitioners for use.

Remaining issues of recommended management in current guidelines for asymptomatic common bile duct stones

Current guidelines for treating asymptomatic common bile duct stones(CBDS)recommend stone removal,with endoscopic retrograde cholangiopan-creatography(ERCP)being the first treatment choice.When deciding on ERCP treatment for asymptomatic CBDS,the risk of ERCP-related complications and outcome of natural history of asymptomatic CBDS should be compared.The incidence rate of ERCP-related complications,particularly of post-ERCP pancreatitis for asymptomatic CBDS,was reportedly higher than that of symptomatic CBDS,increasing the risk of ERCP-related complications for asymptomatic CBDS compared with that previously reported for biliopancreatic diseases.Although studies have reported short-to middle-term outcomes of natural history of asymptomatic CBDS,its long-term natural history is not well known.Till date,there are no prospective studies that determined whether ERCP has a better outcome than no treatment in patients with asymptomatic CBDS or not.No randomized controlled trial has evaluated the risk of early and late ERCP-related complications vs the risk of biliary complications in the wait-and-see approach,suggesting that a change is needed in our perspective on endoscopic treatment for asymptomatic CBDS.Further studies examining long-term complication risks of ERCP and wait-and-see groups for asymptomatic CBDS are warranted to discuss whether routine endoscopic treatment for asymptomatic CBDS is justified or not.

Natural Stone in Jordan： Characteristics and Specifications and Its Importance in Interior Architecture

Architecture in Jordan characterized by using the most basic raw materials in the natural environment （such as stone, straw and mud etc.）. Jordanian designer interacts with natural materials and link these materials to the local environment and the climatic characteristics of the place. This research focuses on the basic material in construction in Jordan, a substance of natural stone, where the researchers studied the historical relationship between architecture in Jordan and natural stone material, and also studied the properties, specifications, types and methods of formation of this natural material. This research aims to shed light on the modern material of architecture in Jordan and how the architects deal with natural stone and other alternative materials where the architects became underestimate the use of natural stone material and use modern materials far from the architectural heritage and which are sometimes not compatible with the construction environment in Jordan. To conclude from this study the importance of maintaining the continuity of the historical relationship between natural stone and Jordanian architecture, where the study recommends to the possibility of development of use this material through using it in interior architecture to conserve on natural stone as a feedstock in the architecture of Jordan.

The NMR core analyzing tomograph:a multi-functional tool for non-destructive testing of building materials

NMR is becoming increasingly popular for the investigation of building materials as it is a non-invasive technology that does not require any sample preparation nor causes damage to the material.Depending on the specific application it can offer insights into properties like porosity and spatial saturation degree as well as pore structure.Moreover it enables the determination of moisture transport properties and the(re-)distribution of internal moisture into different reservoirs or chemical phases upon damage and curing.However,as yet most investigations were carried out using devices originally either designed for geophysical applications or the analysis of rather homogeneous small scale(<10 mL)samples.This paper describes the capabilities of an NMR tomograph,which has been specifically optimized for the investigation of larger,heterogeneous building material samples(diameters of up to 72 mm,length of up to 700 mm)with a high flexibility due to interchangeable coils allowing for a high SNR and short echo times(50-80 ms).

Weightiness and Lightweight for a Temporary Architecture Sustainable

In this paper new criteria for designing of temporary architectures, which can be used as a uniform coverage for open spaces, are discussed. Frequently temporary architectures use building techniques and materials lightweight. In the case of temporary architectures the theme of sustainability requires that the structure can be reused in different occasions and contexts. The solution to these issues, developed in this paper, makes use of a innovative constructive procedure of prestressed masonry in blocks of natural stone. This procedure is used for the construction of the vertical supports of the cover, consisting of a tensostructure with shape of hyperboloid, obtained by products standard （steel profiles and membrane）. The columns with prestressed blocks of natural stone, dry assembled, allow you to have a modular structure, easily assembled and disassembled, with full recovery of all elements; the stone columns, due to their weight, are able to stabilize the whole structure, even to the dynamic stresses, without using any type of foundation structure fixed to the ground. This paper shows the description of all the elements that make up the new type of temporary architecture designed.

Architectural vanguard stone

The modern and updated use of traditional materials in the building industry often proves to improve the performance of the buildings through the economy of management, duration, conditions of comfort and safety, appearance and shelf life. Within this problem a search has allowed us to verify a new building procedure based on the use of reinforced masonry with blocks of natural stone and steel bars and mortar. Then a new phase of research has defined the building procedure of prestressed reinforced masonry with dry-assembled blocks of natural stone. This paper reports the results from a test phase of the research relating to the execution of a full-scale prototype of a panel, with a curved shape, called ＂stone sail＂. This testing allows us to verify the real feasibility of the new building procedure.