An Alternative Method of Measuring SPT Energy

Despite problems associated with its repeatability and reliability, the standard Penetration Test (SPT) continues to be the most widely used in-situ test for liquefaction potential assessment. There are many factors known to influence the SPT results but the most significant factor affecting the N value is the amount of hammer energy delivered into the drill rods. The existing method of SPT energy measurement consists of attaching a load cell near the top of the drill rods and measuring the force time history during hammer impact. An alternative method of SPT energy determ1nat1on based on measurement of both force and acceleration time history is described. It is shown that the proposed method is more fundamental and avoids several shortcomings in the existing method. Field measurements are presented and SPT energies calculated by both methods are compared

General Report Session 3: Deformation and Liquefaction of Sands, Silt, Gravels and Clays

It has been almost 27 years since the damaging earthquakes of 1964 which occurred in Niigata, Japan and in Alaska, USA, focused the geotechnical engineers\u27 attention to liquefaction as a major problem in earthquake engineering. Considerable research and studies have been conducted on the subject of earthquake induced liquefaction since that time and these have included field observations, laboratory experiments and model tests, and theoretical studies. Progress in understanding the liquefaction phenomenon, in the assessment of liquefaction potential, and in the solutions to mitigate the liquefaction hazard has been made, yet the problem remains controversial in many respects, as reflected by the many stimulating papers presented in this session. The word liquefaction has been associated with many phenomena observed in the field during and after earthquakes such as sand boils, flow slides, lateral spreads, loss of bearing capacity and porewater pressure rise. In laboratory tests, liquefaction has been defined in several ways relating to pore pressure buildup under undrained cyclic straining or loading, or the development of a specified amount of shear strain in a fixed number of cycles of loading. Laboratory studies have also shown that the liquefaction phenomenon can be divided into three different behaviors, namely, true liquefaction, limited liquefaction and cyclic mobility. In theoretical studies, liquefaction occurs when the seismic-induced cyclic shear stress exceeds the cyclic shear resistance, or when the seismic porewater pressure increases to equal the effective stress. To compare the results from different papers, one must bear in mind the different definitions used by the various authors. Liquefaction-caused failure is really the result of excessive permanent deformation, e.g. tilting, settlement or heave of structures, excessive slumping or distortion, and sliding of slopes. Liquefaction-induced ground deformation is receiving more attention in the last decade. Soil failure due to liquefaction was the most dominant cause of damage in the recent M 7. 7 Luzon earthquake of July 16, 1990 in the Philippines. Remedial measures or ground improvement techniques to reduce the liquefaction hazards are becoming more common in recent years, not only for seismic rehabilitation of existing sites but also for newly developed sites. Refinements in equipment and techniques of existing methods are being developed. As well, new methods of ground improvements are being introduced. The M 7.1 Lorna Prieta earthquake of October 17, 1989 showed convincingly that liquefaction hazard can be avoided or effectively mitigated by soil densification prior to earthquake

Downhole Seismic Cone Analysis Using Digital Signal Processing

In-situ measurement of the dynamic characteristics of surficial soils is becoming more common in geotechnical practice for prediction of ground surface motions from earthquake excitation and to evaluate foundations for vibrating equipment. Techniques for these measurements have been under development at the University Of British Columbia (U.B.C.) since 1980. The paper discusses many practical considerations with respect to equipment (sources, receivers, trigger, etc.) and procedures that can affect the interpretation and analysis of seismic cone results. A brief review is given of the cross-over method as used at UBC to determine interval shear velocity travel times from downhole seismic cone testing. A more detailed description is provided for the cross-correlation technique used in the frequency domain that has recently been incorporated into the analysis procedure. Comparisons of these two methods are presented and discussed

Liquefaction Characteristics of Undisturbed Soils

Undrained cyclic triaxial tests were performed on undisturbed samples of natural soil deposits in order to investigate some of the factors affecting its liquefaction characteristics. It was shown that when the cyclic deviator stress is normalized with respect to major principal effective stress the number of cycles to liquefaction is not affected by sample size, consolidation stress, anisotropic consolidation, and grain size and density variations. However, liquefaction resistance was markedly increased by increasing over-consolidation ratio and aging. Also, sample disturbance of loose soils results in an increase, or unconservative measurement, of liquefaction resistance

lnsitu Measurement of Damping of Soils

The Seismic Cone Penetration Test (SCPT) has been shown to give reasonable results for insitu measurements of shear wave velocity, and this paper extends this work to include measurements of damping. The relevant equations of motion are described, factors affecting amplitude decay are discussed, and the nature of damping is summarized. Consideration is given to some of the practical aspects of pre-processing of signals. Three methods of damping calculation are presented. The first two, attenuation coefficient and modified SHAKE methods, require the application of amplitude corrections, which is not straight-forward, give variable results, and indicate negative damping in a clayey silt layer. The third, the spectral slope method eliminates the need for amplitude corrections and gives less variable and more acceptable results. The spectral slope method gave damping measurements of about 2% to 3% for sand and 0.3% to 0.5% for silt, at low strain levels of 10-4 to 10-3%

Contralateral prophylactic mastectomies. Correlations between primary tumor and histological findings of controlateral breast

Backgound: In Italy in 2015 48,000 new cases of breast carcinomas were diagnosed. Women who are diagnosed with breast cancer have a significant risk of developing contralateral breast cancer during the rest of their lives and this risk is closely associated to the family history, to the onset of breast cancer at a young age and is expressed at about 0.5 to 1% of metachronous tumors per year. The purpose of this work was to evaluate which and how many neoplastic lesions were seen in the contralateral breast that underwent prophylactic mastectomy and to understand what factors predict the appearance of such lesions. Methods: 168 bilateral mastectomies were analyzed in patients with an average age of 47 years, carried out from July 2008 to April 2016, at the Breast Unit of the Sant’Andrea Hospital. We considered women of any age suffering from unilateral breast cancer without either clinical or radiological evidence of a malignant lesion in the contralateral breast and negative for mutations of the BRCA1-BRCA2 genes test. Of the 168 bilateral mastectomies 35 patients were excluded from the study because they underwent neoadjuvant chemotherapy, another 35 patients because they were suffering from a bilateral neoplasia and 7 cases because they had mutated BRCA1 or BRCA2 genes. Therefore the remaining 91 patients were included in the study. Results: Both the histological features of the primary tumor and any lesions found in the contralateral prophylactic breast were analyzed. Histological examination of the main breast showed 59 cases of Invasive Ductal Carcinoma (IDC), 17 cases of Invasive Lobular Carcinoma (ILC), 9 cases of In Situ Ductal Carcinoma (ISDC), 3 microinvasive ductal, 1 invasive tubular carcinoma, 1 in situ lobular and 1 widespread in situ. In the contralateral breast, the definitive histological examination revealed that 47 patients had an occult lesion in the prophylactic contralateral breast; in particular 2 cases of LIN 1, 7 cases of LIN2, 6 cases of lobular carcinoma in situ, 26 between DIN1A/DIN1A-B/DIN1B, 4 cases of carcinoma in situ and 2 cases of Invasive Ductal Carcinoma. The correlation obtained from the observation of the main tumor has shown that in a total of 59 invasive ductal carcinoma 32 have a controlateral occult lesions and in a total of 17 cases of invasive lobular carcinoma 9 have an occult lesion in the prophylactic breast. Of these lesions, the multicentric relationship is that 50% of invasive ductal and invasive lobular carcinoma of the main breast have a contralateral lesion. Conclusion: In conclusion we would like to remind, as demonstrated by our follow-up data and as the literature reiterates, that this surgery does not improve patient survival. Certainly patients with unilateral breast cancer have many surgical therapies to be able to deal with not only having a bilateral mastectomy. The end point of this work is try to understand the risk factors of having a contralateral breast lesion to reduce the probability of a metachronous cance

PMI: A Delta Psi(m) Independent Pharmacological Regulator of Mitophagy

Mitophagy is central to mitochondrial and cellular homeostasis and operates via the PINK1/Parkin pathway targeting mitochondria devoid of membrane potential (ΔΨm) to autophagosomes. Although mitophagy is recognized as a fundamental cellular process, selective pharmacologic modulators of mitophagy are almost nonexistent. We developed a compound that increases the expression and signaling of the autophagic adaptor molecule P62/SQSTM1 and forces mitochondria into autophagy. The compound, P62-mediated mitophagy inducer (PMI), activates mitophagy without recruiting Parkin or collapsing ΔΨm and retains activity in cells devoid of a fully functional PINK1/Parkin pathway. PMI drives mitochondria to a process of quality control without compromising the bio-energetic competence of the whole network while exposing just those organelles to be recycled. Thus, PMI circumvents the toxicity and some of the nonspecific effects associated with the abrupt dissipation of ΔΨm by ionophores routinely used to induce mitophagy and represents a prototype pharmacological tool to investigate the molecular mechanisms of mitophagy