A new ultrasonic phased array transducer to increase the imaging resolution of the borehole wall is presented for acoustical logging. We fabricate a cylindrical phased array which is made up of 128 piezoelectric elements distributed on the surface of a cylinder uniformly. The working frequency of each element is 0.5MHz. Through the switch array, different combinations of the elements can lead a...

Ground Source Heat Pumps (GSHP) are high efficient HVAC equipment that provide heating and cooling for buildings. The high initial cost of drilling boreholes is one of the main reasons that hinder the widespread application of GSHP. It is very important to develop proper design methods to predict and evaluate the performance of the Ground Heat Exchanger (GHE) throughout its entire life span. In...

A deep borehole repository is one of the four geologic disposal system options currently under study by the U.S. DOE to support the development of a long-term strategy for geologic disposal of commercial used nuclear fuel (UNF) and high-level radioactive waste (HLW). The immediate goal of the generic deep borehole repository study is to develop the necessary modeling tools to evaluate and impro...

Objective: To observe the clinical effects of minimally invasive puncture and borehole drainage for the treatment of chronic subdural hematoma. Methods: 100 chronic subdural hematoma patients were randomly divided into the control group and the observation group. The observation group was given minimally invasive puncture. The control group was given borehole drainage. Indexes and total effecti...

A variety of established and experimental geophysical techniques was used to measure the vertical distribution of fracture permeability in a 229-meter deep borehole penetrating schist and quartz monzonite near Mirror Lake, New Hampshire. The distribution of fractures in the borehole was determined by acoustic borehole televiewer and other geophysical logs. Fracture permeability was estimated by...

To investigate the propagation of flexural waves in a borehole surrounded by an azimuthally anisotropic hard formation, we made an ultrasonic borehole model of Delabole slate with very strong anisotropy. The axial and azimuthal acoustic fields generated by a dipole source were measured in the fluid-filled borehole. The results show that there are three dominant wave modes: fast and slow flexura...

A vertical geothermal probe consists of two or four polyethylene tubes U-shaped, used for circulating the coolant between the heat pump and the ground. It is installed in a deep borehole and sealed in a special grout, a kind of liquid cement, used to seal the borehole, and avoid the presence of air bags between the probe and the ground. Moreover, the grout provides a heat transfer medium betwee...

The temperature response in the soil surrounding multiple boreholes is evaluated analytically and numerically. The assumption of constant heat flux along the borehole wall is examined by coupling the problem to the heat transfer problem inside the borehole and presenting a model with variable heat flux along the borehole length. In the analytical approach, a line source of heat with a finite le...

The in situ thermal conductivity of the subsurface has been measured with a novel thermal response test using heating cables inserted in a vertical ground heat exchanger. An electric current is applied along the cables to heat the borehole prior to measuring water temperature recovery at various depths inside the ground heat exchanger piping. The one-dimensional line-source equation, combined w...

Oil shale is a kind of potential alternative energy source for petroleum and has attracted the attention of energy researchers all over the world. Borehole hydraulic mining has more prominent advantages than both conventional open-pit mining and underground mining. It is very important to attempt to use the borehole hydraulic mining method to exploit underground oil shale. The nozzle is the key...