Introduction: Weathering is the mechanical and chemical hammer that breaks down and sculpts the rocks. it cause the disintegration of rock near the surface of the earth. Plant and animal life, atmosphere and water are the major causes of weathering, Weathering breaks down and loosens the surface minerals of rock, and thus should not be confused with erosion, which involves the movement of rocks and minerals by agents such as water, ice, snow, wind, waves and gravity and then being transported and deposited in other locations. There are two major classifications of weathering processes exist, the first one is physical weathering and the second on is chemical weathering; each sometimes involves a biological component. Mechanical or physical weathering is the process of breaking big rocks into little ones.
Abstract: Conical picks are the essential cutting tools used especially on mining excavators., and tThe cutting performance and the wear of pick affect the efficiency and the cost of rock/mineral excavation directly. In this research, in order to better understand the mechanism of rock fragmentation by conical pick and the wear mechanism of a pick, a numerical model of rock fragmentation by conical pick is established with the aim of revealing the rock fragmentation mechanism and pick wear mechanism, and explaining the reasons for crushed zone and crack formation under the cutting load, which include the fracture processes of the rock specimen and the mechanism of crushed zone formation, crack initiation and propagation. Then, the conical pick
Water erosion or flowing water continuously shape and reshape landscape of the land. The property of water to lift and transport loose rock fragments can wear rocks by acting abrasively in other rocks. Water can even dissolve minerals present in soil and carry it downstream before deposition. Rainwater falls on slopes runs on downhill creates cut small channels known as rills. Rills when deepen further form gullies end soon join rivers and streams.
A. et al., 2006 further divides the heat source in cutting into 3 different stages, namely; • Primary deformation zone, where heat is generated through elasto-plastic deformation at the shear zone. • Secondary deformation zone, where heat is due to plastic deformation and the sticking-sliding friction of the tool rake face and the work piece. • Tertiary deformation zone, where further heat is generated through elastic deformation and rubbing friction of tool flank (clearance) face with the work piece shown in figure. One of the important phenomenon along with the temperature that inhibits the machining of nickel alloys is work hardening. Work Hardening occurs when metal ahead of the tool is plastically deformed.
Avalanches are usually caused by mechanical failure when the force on the snow exceed its strength and causes the snow to loosen and gradually slide down a slope. As they start to slide, the speed of the avalanches increase rapidly as they entrain more snow and grow in size. The causes of avalanche very from metamorphic changes in the snowpack such as melting due to solar radiation to natural causes such as storms, earthquakes, rock fall, icefall and
The unit is connected to a computer for automated data acquisition and control. The device performs all data calculations for a direct reading of permeability. The core is placed in a rock core holder, and the outer surface is pressurized to simulate the loads, that the core was under when it was removed. Of these loads or stresses, some are caused by the weight of the material above the core, which is known as the “overburdened” pressure. Loads on the rock will affect the core’s permeability to fluids, so it is important to duplicate them during testing.
Cultural Heritage's bio-degradation Cultural valuable objects correspond to a large variety of raw materials: stone, clay, wood, pigments, mortar, metal, etc... None of them is immune to decay, also known as degradation. Due to the objects' significance for local and international communities, it is of prime importance to understand their decay and help preserve them. Although, materials' degradation involves numerous parameters, it is possible to reduce them to two main factors: weathering, and biodegradation. Weathering consists in materials' irreversible breakdown due to the direct contact with its surrounding environment. Humidity, temperature, ventilation, pollution are some aspects that take a crucial role in materials' weathering.
location and on the same seismograph. The Richter Scale difference was an increase of one. Water play a significant role in ground failure during an earthquake. The water is place into spaces and create a rhyme for the earthquake. The water can also spread the grain apart and to start a massive slide downward.
Water is one of the main factors of decay of alabaster stone which one of the porous stone at Karnak and Luxor temples, as it plays a crucial role in almost every decay process, water penetrate into the pores of the stone by many ways as capillary suction from the soil or by condensation from the atmosphere. Thus water carries into the stone soluble salts which can crystallize in correspondence of the evaporation surface owing to the solution supersaturation. This process is the main cause of the efflorescence and subefflorescence formation. Halite and gypsum are the common salts at the alabaster stone in Upper Egypt. Halite and Gypsum are hygroscopic salt
There are also anthropogenic activities that contribute to landslides including heavy machine vibrations in the ground, irrigation, and deforestation that can make fragile slopes unstable. The composition and geological structure of the earth substrate or rock can influence to the frequency and type of landslide that might occur in a certain area. The natural weathering, as well as tectonic activity can affect the strength and cohesion of the earth substrate. The activity leads to make the soil structure vulnerable and easy to slip downhill that increases the propensity for landslide incident (Chen, 2006). According to the Mines and Geosciences Bureau (2010), with the changing weather conditions and amount of rainfall each season brings, we could categorically state the number of landslide occurrences is increasing.