Redesign of an auto-levelling base for submarine seismic sensor

The OBS (acronym of Ocean Bottom Seismometer) is a system to monitor the submarine seismic activity. To properly work, an OBS system needs a suitable auto-levelling base to maintain a fixed (horizontal) position during the measurement phases. In this work a new auto-levelling base for submarine seismic sensors has been designed. During the redesign process a preliminary phase of analysis of the state of art has been made. Afterwards, the technological solutions chosen by different manufactures have been critically analysed, and a full description of their functionalities, working principles and system performances has been carried out. Later, some innovative concepts have been proposed. Among these ones, the most interesting are the auto-levelling bases with spherical joint, based on: air bearings, ball bearings and magnetic levitation systems. The concept scoring method has been used to identify. as best concept, the auto-levelling base with spherical joint and air bearings system. Successively, the chosen concept has been implemented: the technical working principles have been studied to choose the best solutions in terms of dimensions, shapes, materials of all base components. A full parametric CAD model of the auto-levelling base has been also created. The new designed base, by using a very innovative auto-levelling system, allows to obtain very good results as regards the accuracy of positioning, so ensuring a remarkable improvement of the performances of the ocean bottom seismometers

SUSPECTED CHILD ABUSE: UNUSUAL DEATH IN WESTERN COUNTRY. SUICIDE OR HOMICIDE?

This case report describes a particular case of carbonized corpse, found in his burnt-out car in an isolated Palermo’s west suburban zone. The goal of this case report is to describe the shame and the social stigma related with suspicious of pedophilia and how it led a man to suicide by fire, considering that is an unusual way to die in western countrie

Damped mechanical oscillator : experiment and detailed energy analysis

The damped oscillator is discussed in every high school textbook or introductory physics course, and a large number of papers are devoted to it in physics didactics journals. Papers typically focus on kinematic and dynamic aspects and less often on energy. Among the latter, some are devoted to the peculiar decreasing behavior of energy characterized by ripples, which can easily be demonstrated by using a dynamic modeling approach. In this note we consider an oscillator consisting of a cart running on a horizontal track, two springs, and a damping device created with magnets and a metal plate attached to the cart. Using sensors and data-acquisition software, we measure kinematic quantities and three forces: those of the springs on the cart and, separately, the force between magnets and the plate. A detailed analysis of the energy exchanges between the cart and the interacting parts is obtained. In particular, we show that only the energy exchanges with the magnets are affected by dissipative processes while over a suitable time interval the net energy exchanged between cart and springs equals zero

REDESIGN OF AN AUTO-LEVELLING BASE FOR SUBMARINE SEISMIC SENSOR

The OBS (acronym of Ocean Bottom Seismometer) is a system to monitor the submarine seismic activity. To properly work, an OBS system needs a suitable auto-levelling base to maintain a fixed (horizontal) position during the measurement phases. In this work a new auto-levelling base for submarine seismic sensors has been designed. During the redesign process a preliminary phase of analysis of the state of art has been made. Afterwards, the technological solutions chosen by different manufactures have been critically analysed, and a full description of their functionalities, working principles and system performances has been carried out. Later, some innovative concepts have been proposed. Among these ones, the most interesting are the auto-levelling bases with spherical joint, based on: air bearings, ball bearings and magnetic levitation systems. The concept scoring method has been used to identify. as best concept, the auto-levelling base with spherical joint and air bearings system. Successively, the chosen concept has been implemented: the technical working principles have been studied to choose the best solutions in terms of dimensions, shapes, materials of all base components. A full parametric CAD model of the auto-levelling base has been also created. The new designed base, by using a very innovative auto-levelling system, allows to obtain very good results as regards the accuracy of positioning, so ensuring a remarkable improvement of the performances of the ocean bottom seismometers

Dentistry and Drug Adverse Events: Between Responsibilities and Regulations

The purpose of this paper is to renew interest and attention to the medical history, prescription, and/or use of drugs during dental practice. The work analyzes the issue of the use of drugs in dentistry from both a clinical and a medical-legal point of view. The laws governing the matter were also taken into consideration, relating them to the roles of prescriber and user that the dentist can acquire. Analysis of various aspects of this matter demonstrates that it is necessary for dentists to know the drugs and medical substances, their characteristics and properties, related effects, and interactions in order to use them appropriately and adequately. Knowledge of interferences, reactions, and adverse events or complications helps to reduce errors and protect patients' health. Furthermore, knowledge of the national and international reference standards relating to the use of drugs leads to a reduction in medico-legal questions. In conclusion, knowledge and adequate and appropriate use of drugs reduces the possibility of accidents, adverse events, medico-legal consequences, and disputes with patients. Documented and traceable choices allow the analysis and valuation of professional conduct. Authors perceived the topic of informed consent of patients as relevant to the adequate procedure of prescribing drugs related to dentistry practice; therefore, representative conditions of patients at risk should be illustrated in practice. Legal duties related to physician drug prescription and use must be considered and carefully checked

Gait disturbance and lower limb pain in a patient with PIK3CA-related disorder

Post-zygotic activating mutations in PIK3CA and other genes encoding members of PI3K-AKT-mTOR pathway have been found in various overgrowth syndromes that have been grouped together as PIK3CA-related overgrowth spectrum (PROS). We report a female patient with gait disturbance, leg pain, isolated macrodactyly of the foot, and mild intellectual disability. Imaging of the lower limb showed a lipoblastoma of the right thigh. A mosaic gain-of-function mutation in the catalytic domain of PIK3CA (c.3140 A > G; p.His1047Arg) was detected in the adipose tissue and in skin cultured fibroblasts from the macrodactyly but not in blood. The leg pain and the severe walking disturbance improved slightly over time and serial MRI of the lower limbs suggested that the size of the lipoblastoma relative to the lower limb muscles or to the whole lower limb was unchanged as consequence of limb growth. This case report illustrates that pain and gait disturbance can be features of PROS and highlights the need of better knowledge about the natural history of the disease