Short-term expansion planning of radial electrical distribution systems using mixed-integer linear programming

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Mixed-integer convex model for VAr expansion planning

This paper presents a mixed-integer convex-optimization-based approach for optimum investment reactive power sources in transmission systems. Unlike some convex-optimization techniques for the reactive power planning solution, in the proposed approach the taps settings of under-load tap-changing of transformers are modeled as a mixed-integer linear set equations. Are also considered the continuous and discrete variables for the existing and new capacitive and reactive power sources. The problem is solved for three significant demand scenarios (low demand, average demand and peak demand). Numerical results are presented for the CIGRE-32 electric power system.

A comparative, prospective and randomized evaluation of roux-en-y gastric bypass with and without the silastic ring: a 2-year follow up preliminary report on weight loss and quality of life

Currently, Roux-en-Y gastric bypass (RYGB) is one of the most widely used bariatric surgeries. Banding the pouch forms a banded gastric bypass operation, an accepted and frequently used variant. Placing a silastic ring around the pouch to band the gastric bypass operation increases the restriction mechanism. However, the ubiquitous use of the banded gastric bypass remains controversial. One of the controversies is the effect of the silastic ring on patients' perception of their well being after surgery because of the frequency of vomiting. A prospective, blindly randomized, comparative trial was undertaken to resolve this controversy. Four hundred subjects scheduled for gastric bypass surgery were randomized into two arms of the trial, 200 with a silastic ring (WR) and 200 without (NR). After 2-year follow-up, the variables associated with the scores of Bariatric Analysis and Reporting Outcome System (BAROS) were analyzed. The initial median weight (125 kg), BMI (47), and age (36 years) were the same in both the NR and WR groups. The median excess weight loss, weight regain, and incidence of vomiting were 71, 10.5, and 7.75 %, respectively, in the NR group vs. 75.4 and 1.1, and 24.4 % in the WR group. The mean QOL score was 79 % in the NR group vs. 80 % in the WR group. After 2-year follow-up, silastic ring placement in the RYGB resulted in greater weight loss and weight stability and a threefold greater incidence of vomiting. There was no difference in the scores in the quality of life analysis.

Algebraic solution of an anisotropic ring-shaped oscillator

Using an algebraic technique related to the SO (2, 1) group we construct the Green function for the potential ar2 + b(r sin θ)-2 + c(r cos θ)-2 + dr2 sin2θ + er2 cos2θ. The energy spectrum and the normalized wave functions are also obtained. © 1990.

Sistemas de retenção O'ring e barra-clipe em overdenture mandibular

The dissatisfaction of the treatment with mandibular complete dentures in edentulous patients has been a constant problem in Dentistry. Often, the absence of stability and retention, resultants of a physiologic condition and alveolar ridge resorption, bring reduction of chewing force, speech problems and social life interference. In these cases, the rehabilitation over osseointegrated implants can be an effective and safe alternative of treatment. When it is not possible to put implants in appropriate number and disposition, it is necessary to make a simple and low costing prosthetic planning, which makes resurge the overdentures. Various implant supported attachment systems for overdentures have been developed in the dental market. Thus, intending to facilitate the professional choice, this study review the literature about attachment systems O’ring and bar- clip in its following aspect: retention level, stress distribution, hygiene complications and patient satisfaction.