Gpr: Fill & Download for Free

The "bitness" of a system (and specifically it's CPU) is generally accepted to be defined by the bit-size of its general purpose register file (GPR) and to a lesser extent, it's system bus width. On 32-bit machines, the GPRs are 32-bits in size; on 64-bit machines, the GPRs are 64-bits in size.The GPR is responsible for holding data values that the CPU is going to use for processing. Thus, they directly represent the data types the CPU can work on. When calculating a memory address, the CPU must get that data from a register (or as part of the instruction, which is typically much smaller than a register in bit-length), so a CPUs directly-mapped memory space (per process) is limited to 4GB for a 32-bit CPU and 16EB for a 64-bit CPU.That is not to say, however, that the CPU can't access more than 4GB of memory. Intel's physical address extensions and ARM's recent virtualization extensions, for instance, allow the CPU to access memory greater than 4GB. However, a translation stage must be utilized for the CPU to do so.Another implication of a 32-bit GPR is that arithmetic data (such as ADD, multiply, etc.) are limited to 32-bits. However, it should be noted that most CPUs contain more than just the main arithmetic logic unit (that operates from GPRs) but also either a vector or FP execution unit (SSE for Intel, NEON for ARM).These operate from different registers and do not rely on the GPR to feed their datapaths. On ARMv7-A, NEON instructions are provided that can operate on 64-bit integers despite the architecture being "32-bit". Registers for both NEON and SSE implementation are 128-bits in width (SSE’s follow-on AVX goes up to 512-bit with their Intel’s latest AVX-512 - Wikipedia).

Well, I have tried GPR for archaeological finds but the success was not so great as compared to other objectives of GPR. Basically GPR works on pattern recognition technique and except for major archaeological finds, GPR will have little say in detecting smaller scattered buried objects. If we have some idea of what we are going to look or find out, GPR survey can be quite handy. Similar is true with resistivity imaging. Both GPR and resistivity and provide quite precise depth information but they should be aptly used for larger targets. Use of GPR in detecting mass graves is well documented.But there are some areas like mapping damage zones or loose matrix in archeological structures where there is no alternative to GPR. As regards cost of survey, GPR is not expensive compared to other geophysical methods. So with more use of GPR in supporting archeological finds will refine the technique further.

Detection by GPR is mainly done by pattern recognition technique in which the target body or defect is identified by specific geometrical signature on the radargram. Gold is a vein deposit and occurs sparsely with the host rock. Even in hay days at KGF mines in India, Gold content was 10gm/ton of ore (average). With such sparse and vein type of characteristic of gold ore, its detection by GPR by conventional reflection method is ruled out. For that matter GPR cannot be used for exploration of any other metal deposits too unless they occur as sheet deposits.One of the reasons for limited application of GPR in exploration is that in most of the cases, the medium or target is always identified in time domain (reflection). There is no plot of medium properties in the radargram. Once this feat is achieved like plotting GPR sections in terms of dielectric constant or permittivity of the medium, GPR can succeed very well as an exploration tool. I have seen very few publications in this direction. But I am hopeful (we are working on that) that very soon we will have radargrams like seismic sections with contours of medium properties with depth.But story does not end here. We have experimented with GPR tomography to detect sparse metal deposits. The same can be extended for gold detection through boreholes. In stopes of mined out regions, presence of gold is tested by deep drill-holes on the face. We can use two such drill-holes to carry out GPR tomography in stopes where drilling has not yielded positive results. By using Hilbert transform, we can make magnitude plot in the tomogram to identify the gold veins by its low attenuation signature. A proposal to this effect is in the anvil for experimentation. So, I feel, borehole GPR survey can supplement drill-hole exploration data for detection of gold.