Design and Applications of Multi-Frequency Holographic Subsurface Radar: Review and Case Histories

Holographic subsurface radar (HSR) is not currently in widespread usage. This is due to a historical perspective in the ground-penetrating radar (GPR) community that the high attenuation of electromagnetic waves in most media of interest and the inability to apply time-varying gain to the continuous-wave (CW) HSR signal preclude sufficient effective penetration depth. While it is true that the fundamental physics of HSR, with its use of a CW signal, does not allow amplification of later (i.e., deeper) arrivals in lossy media (as is possible with impulse subsurface radar (ISR)), HSR has distinct advantages. The most important of these is the ability to do shallow subsurface imaging with a resolution that is not possible with ISR. In addition, the design of an HSR system is simpler than for ISR due to the relatively low-tech transmitting and receiving antennae. This paper provides a review of the main principles of HSR through an optical analogy and describes possible algorithms for radar hologram reconstruction. We also present a review of the history of development of systems and applications of the RASCAN type, which is possibly the only commercially available holographic subsurface radar. Among the subsurface imaging and remote sensing applications considered are humanitarian demining, construction inspection, nondestructive testing of dielectric aerospace materials, surveys of historic architecture and artworks, paleontology, and security screening. Each application is illustrated with relevant data acquired in laboratory and/or field experiments

Design and Applications of Multi-Frequency Holographic Subsurface Radar: Review and Case Histories

Holographic subsurface radar (HSR) is not currently in widespread usage. This is due to a historical perspective in the ground-penetrating radar (GPR) community that the high attenuation of electromagnetic waves in most media of interest and the inability to apply time-varying gain to the continuous-wave (CW) HSR signal preclude sufficient effective penetration depth. While it is true that the fundamental physics of HSR, with its use of a CW signal, does not allow amplification of later (i.e., deeper) arrivals in lossy media (as is possible with impulse subsurface radar (ISR)), HSR has distinct advantages. The most important of these is the ability to do shallow subsurface imaging with a resolution that is not possible with ISR. In addition, the design of an HSR system is simpler than for ISR due to the relatively low-tech transmitting and receiving antennae. This paper provides a review of the main principles of HSR through an optical analogy and describes possible algorithms for radar hologram reconstruction. We also present a review of the history of development of systems and applications of the RASCAN type, which is possibly the only commercially available holographic subsurface radar. Among the subsurface imaging and remote sensing applications considered are humanitarian demining, construction inspection, nondestructive testing of dielectric aerospace materials, surveys of historic architecture and artworks, paleontology, and security screening. Each application is illustrated with relevant data acquired in laboratory and/or field experiments

Discussion of the Non-Destructive Testing Possibilities for the Study of the Great Pyramid of Giza

Many constructions built by ancient civilization hold many mysteries and attract the attention of historians, archaeologists and tourists from all over the world. The most famous and enigmatical among them is the Great (Khufu’s-Cheops’) Pyramid on the Giza plateau in Egypt. The assignment, construction methods and especially the inside structure of the Pyramid have been the cause of heated debate among historians and researchers since ancient times. Unfortunately, not only researchers are interested in ancient structures and excavation sites of archaeological values, but also robbers and illegal seekers of archaeological values. This led to the partial destruction of the Pyramid by the order of the Arab caliph Al-Ma’mun in the 9th century AD. From the middle of the last century, the point of view has prevailed that only non-destructive testing methods are acceptable when examining ancient structures. In the 1960s, a technology was proposed for transilluminating the pyramids of Giza by muons, which are generated by cosmic rays in the Earth’s atmosphere. This method gave promising results. Other means were also proposed, which include radar, as well as gravitational and vibration technologies. However, despite numerous attempts to use them, no significant success or discovery has been achieved. A discussion of these methods, their applications and partial successes is the subject of this article

Simultaneous operations for gastric cancer and aortic aneurysm: a case report

Abstract Background Gastric cancer is the second highest cause of morbidity among malignant tumors of the gastrointestinal tract and fifth in overall cancer statistics. Diseases of the cardiovascular system are the leading causes of death in the world. Aneurysm of the abdominal aorta is the most common type of vascular aneurysm, while in 75% of the cases it is asymptomatic. The risk of rupture of aneurysm of the abdominal aorta increases progressively depending on its diameter and the age of the patient. Case presentation A 56-year-old male patient underwent treatment for complaints of pain and discomfort in the epigastric region, general weakness and difficulty in passing food through the esophagus. The neoplasm extended to the esophagus up to 17–20 mm (pT3N3aM0 R0 stage IIIB TNM 8). The aortic diameter at the level of the renal arteries was 18 mm; lower than the main renal arteries, an expansion of up to 60 mm was visualized; the length of aneurysm was 105 mm extending to the bifurcation. A gastrectomy with a resection of the lower thoracic esophagus and application of a manual double-row Roux-en -Y esophagojejunal anastomosis with cholecystectomy and D2 lymphadenectomy was done along with longitudinal aneurysmectomy and thrombectomy. The proximal anastomosis between the aorta and the synthetic linear prosthesis of 18 × 9 × 9 mm in the end-to-end type was formed by a continuous winding suture with the “Prolene” 5-0 thread. The end-to-end distal anastomosis of the prosthesis and aorta branch was formed by continuous winding suture with the “Prolene” 6-0 thread. The postoperative period proceeded without features and complications. On the 7th day after the surgery, the patient was discharged home in satisfactory condition. Conclusions Performing a simultaneous operation allowed the patient to undergo rehabilitation after the treatment of two diseases during one hospitalization and, in the shortest possible time, to proceed to the next stage of gastric cancer treatment—chemotherapy, thereby improving the prognosis of life expectancy. Also, one-stage surgical treatment of concomitant aneurysm of the abdominal aorta and gastric cancer is well tolerated and can avoid financial costs, and patient anxiety involved in a second operation

On the Use of Microwave Holography to Detect Surface Defects of Rails and Measure the Rail Profile

The use of microwave holography for detecting rail surface defects is considered in this paper. A brief review of available sources on radar methods for detecting defects on metal surfaces and rails is given. An experimental setup consisting of a two-coordinate electromechanical scanner and a radar with stepped frequency signal in the range from 22.2 to 26.2 GHz is described, with the help of which experimental data were obtained. Fragments of R24 rails with surface defects in their heads were used as the object of study. The radar images of rail defects were obtained by the described method based on back propagation of a wavefront. It is shown that polarization properties of electromagnetic waves can be used to increase the contrast of small-scale surface defects. A method of estimating rail surface profile by radar measurements is given and applied to the experimental data. Comparison of the longitudinal rail head profiles obtained by radar and by direct contact measurements showed that the radar method gives comparable accuracy

Comparison of Bioradiolocation and Respiratory Plethysmography Signals in Time and Frequency Domains on the Base of Cross-Correlation and Spectral Analysis

Comparison of bioradiolocation and standard respiratory plethysmography signals during simultaneous registration of different types of the human breathing movements is performed in both time and frequency domains. For all couples of synchronized signals corresponding to bioradiolocation and respiratory plethysmography methods, the cross-correlation and spectral functions are calculated, and estimates of their generalized characteristics are defined. The obtained results consider bioradiolocation to be a reliable remote sensing technique for noncontact monitoring of breathing pattern in medical applications