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Many men, three wars, and one question: Foundations for the modern understanding of Pain
For the last years, PV (photovoltaic) generation has been having an important impact on LV (low voltage) and MV (medium voltage) grids in Spain, due to the increasing number of installations. As power monitoring of the generation is in most cases not required, utilities are forced to make assumptions on PV power generation in order to perform network planning studies for both peak demand and contingency analysis. These assumptions increase errors committed during the analysis, as the number of PV installations increases. This paper presents a methodology for estimating PV active power generation values for planning purposes in MV and LV power systems, from historic generation data, based on the development of correlation models. This methodology is applied to three different examples, using predictors based on real registered data. The methodology was also applied in a typical grid study and it's error was determined.
Distribution network and transmission system operators (DNOs and TSOs) who are obliged to connect photovoltaic-distributed generation (PV-DG) to their respective distribution networks or power systems need a coherent set of electrical protection requirements for safe operation. Nonetheless, the growing importance of PV-DG has prompted continuous reformulations of these requirements. Within this context, this paper gives a detailed overview of electrical protection requirements for PV-DG grid-interconnection from the LV to the HV-EHV level. For this purpose, we have analysed national and regional codes that have been proposed and enacted in many countries where high PV penetration levels have been achieved or are expected to be achieved in the future. This survey focuses on protection relays and their settings. Also included are the ancillary services to be provided by PV-DG, specifically at the HV-EHV level.
William Williams Keen was the catalyst for the advent of neurosurgery in the United States. He served in the Civil War and collaborated with Silas Weir Mitchell in studying injuries sustained to the nervous system. These studies culminated in the publication in 1864 of "Gunshot Wounds and Other Injuries of the Nerves and Reflex Paralysis," which first described causalgia, reflex sympathetic dystrophy, and secondary paralysis. His most monumental accomplishment undoubtedly was being the first surgeon in the United States to successfully remove a primary brain tumor (1887) and have the patient survive for more than 30 years. As the editor of "Surgery, Its Principles and Practice," Keen invited Harvey Cushing to write the section on surgery of the head, which propelled Cushing to international recognition and provided a foothold for the new specialty of neurosurgery. Multiple sources were reviewed to prepare this comprehensive biographical account of Keen's contributions. Emphasis is placed on those achievements that furthered the discipline of neurosurgery. Although a general surgeon, Keen had a special interest in the nervous system. He treated patients with trigeminal neuralgia, performed cortical excisions for patients with epilepsy, and devised the procedure of posterior upper cervical root sections for spasmodic torticollis. He was the first surgeon to perform and advocate ventricular punctures. He served as a consultant and surgeon to both Grover Cleveland and Franklin Delano Roosevelt.
IN 1887 William James reported to the American Society for Psychial Research his study of 185 persons after amputations, his interest in this subject being no doubt stimulated by the fact that his father had had a midthigh amputation. It may seem strange today that a professor of philosophy should probe into so unphilosophical a matter as phantom pain, but it is pertinent to recall that James was an assistant professor of physiology before he began his pursuit of philosophy. James, in this report, noted that three fourths of the persons studied had sensations referred to the lost part, some . . .