► We modeled the load by three probability models. ► We include a node with wind generation of 20. ► We modeled wind by a Weibull distribution. ► We modeled the wind turbine as a three possible liner ...functions. ► We developed a method using analytical probability to determine the voltage profile of a network.
Exploitation of renewable energy sources in power networks, especially wind energy, is considered an alternative for power generation as a non-polluting source with a low environmental impact and low operational cost. Hence, renewable energy has motivated the increment of penetration of Distributed Generation (DG) in distribution networks and the development of methodologies to evaluate their effects in the electrical system, which is characterized by uncertainties at all levels (generation, network and load). In this paper, a new analytical approach is explored to formulate and solve the Probabilistic Load Flow (PLF), which shows the voltage profile of a network including uncertainties of power injections and consumption. This approach is based on the linearization of load flow (LF) equations for Radial Distribution Systems (RDSs) using the probabilistic arithmetical laws. The solution is compared to Monte-Carlo Simulation (MCS), which is the most common simulation used to solve the PLF problem.
The use of computational evolutionary strategies in the design of metamaterials with desired thermal expansion coefficients is uncommon due to the discrete nature of the design variables. This work ...presents a Bi-directional Evolutionary Structural Optimization (BESO) based methodology for designing orthotropic metamaterials with a specific thermal expansion coefficient using an objective function considering only the thermal expansion coefficients, with no constraints on geometry or stiffness. Topologies of the metamaterials, composed of two material phases and a void, are obtained using a material interpolation between neighboring material phases and three easy-to-implement numerical strategies to stabilize the evolutionary process. Two are on the sensitivity calculation and one is on the addition ratio’s value. The strategies applied to the sensitivity numbers are proposed to avoid the positive and negative values of the elemental sensitivity numbers and the element change between no neighboring materials. Additionally, the addition ratio’s value reduction strategy assures the convergence of the thermal expansion properties to the desired value. The homogenization method is used to obtain the equivalent thermal expansion properties of the designed materials. Some numerical examples are presented to show the potential and effectiveness of the proposed methodology.
This study set out to investigate the efficiency of long-term estrus synchronization protocols and ovulatory follicle dynamics in ultrasonographically monitored Santa Inês ewes during lengthening ...(LD; September−October) and shortening photoperiods (SD; April−May), and the transitional period (TP; January). In addition, the influence of ovarian status (e.g., size of antral follicles and/or presence of corpora lutea) at the outset of the estrus synchronization protocols on the ensuing development of ovulatory follicles was examined. Seventy sexually mature Santa Inês ewes were subjected to one of the two estrus synchronization regimens; on Day 0 (random day of the estrous cycle or anovulatory period), the ewes were fitted with an intravaginal progesterone (P4)-releasing (controlled intrauterine drug release CIDR) device, which was left in place for 14 days (G-1CIDR, n = 35) or replaced on Day 7 (G-2CIDR, n = 35), and received an intramuscular injection of 10 mg of PGF2α. The ewes allocated to the G-1CIDR group had mean serum P4 concentrations less than 2 ng/mL during the last 4 days of the synchronization protocol. There were no differences (P > 0.05) in mean ovulation rates between the two protocols tested nor among the ewes varying in ovarian status or studied at different times of the year, but ovulations occurred ∼12 hours later in the TP compared with the SD period (P < 0.05). Ovulatory follicles emerged earlier (P < 0.05) in the G-1CIDR group than in the G-2CIDR group (Day 8.3 ± 0.5 vs. 9.2 ± 0.4) and during LD (Day 7.1 ± 0.6) compared with the TP (Day 9.1 ± 0.6) and SD (Day 9.9 ± 0.5 of the protocol). In conclusion, the replacement of CIDR devices prevented the occurrence of lower-than-normal luteal phase levels of P4 at the end of the 14-day estrus synchronization protocol. However, although this procedure and seasonal influences altered certain growth characteristics of ovulatory follicles, there were no effects of these factors on the mean ovulation rate.
This paper presents a concurrent topology optimization methodology for minimizing the frequency responses of multiscale systems composed of macro and micro phases. Although there is existing research ...on the topology optimization of structures and optimization of the materials for frequency responses, topology optimization approaches considering both scales simultaneously are relatively limited. The methodology proposed here aims to apply the bi-directional evolutionary structural optimization (BESO) method to find the optimum layout on both macro and micro scales of the structure, with the objective of minimizing the frequency response in the macro structure. For this coupled system, it is assumed that the macro structure is composed of a periodic material whose effective properties are obtained using the homogenization theory. The designs of the macro and micro structures are conducted simultaneously. The homogenized elasticity matrix used in the finite element analysis of the macro structure is obtained from considering the layout of the micro structure. A series of numerical examples are presented to validate the optimization procedure and to demonstrate the effectiveness and the efficiency of the proposed method.
A numerical study (conjugate modeling) of potato cuboid separation in convective drying is performed with the Large Eddy Simulation approach. Any in-line potato array is represented by a single ...interacted zone through periodic boundary conditions. Numerical code is validated with four experimental studies focused on hydrodynamics (two cases), heat transfer (one case), and mass transfer (one case). Twelve case studies have been proposed to study the effect of streamwise and spanwise distances on heat and mass transfer. Results show that low streamwise separations (0.25) strongly affect the potato drying by the presence of a quasi-stationary wake that causes a blocking effect. The potato cuboid's best thermal uniformity and mass transfer are presented at a spanwise distance (0.75) and streamwise separations (1.0). Results can be applied to get uniform heat and mass transfer in drying chambers.
This article proposes an acoustic muffler design procedure based on finite element models and a Bi-directional Evolutionary Acoustic Topology Optimization. The main goal is to find the best ...configuration of barriers inside acoustic mufflers used in the automotive industry that reduces sound pressure level in the outlet of the muffler. The acoustic medium is governed by Helmholtz equation and rigid wall boundary conditions are introduced to represent acoustic barriers. The continuum problem is written in the frequency domain and it is discretized using the finite element method. The adopted objective function is Transmission Loss (TL). Increasing TL guarantees that the sound pressure level ratio between outlet and inlet of the muffler is reduced. To find the configuration of acoustic barriers that increases the Transmission Loss function of the muffler an adaptation of the Bi-directional Evolutionary Structural Optimization (BESO) method is used. Applying the proposed design procedure topologies in 2D models are reached, which raises the Transmission Loss function for one or multiple frequencies. Three examples are presented to show the efficiency of the proposed procedure.
•Helical segmented-fins create complex turbulent structures into the inter-fine space.•The instantaneous fields obtained by the large eddy simulation give complementary information about the ...turbulence.•A full turbulent study is necessary to know the performance of a heat exchanger.•The inter-segmentation space favors the exchange of momentum and energy.
The Large Eddy Simulation approach was used to perform a numerical simulation of a flow around a circular tube bundle. The model is based on numerical tools, such as the immersed boundary technique and the extrapolation of pressure in the solid region of the tube, to represent a helical segmented-fin tube geometry. The simulation was conducted in an area away from the boundaries of the tube bundle, where the flow is fully-developed, and the use of periodic boundary conditions was possible. The mean velocity and turbulence values of the results and experimental data were compared and showed good general agreement. From the instantaneous results, it was possible to observe and study different turbulent structures presented in the flow. Two counter-rotating horseshoe vortices were identified in the space between the fins, which can improve heat transfer. Furthermore, a relevant transfer of momentum in the inter-segment space and contiguous zones was observed.
•Antral follicular blood flow was assessed throughout the 4-day superovulatory regimen in ewes.•High-velocity blood flow (HVBF) was quantified with computerized analyses of color Doppler images.•HVBF ...on the 2nd day of the superovulatory treatment was related to ovulation rates and embryo yields.•HVBF on the last day of the superovulatory treatment was indicative of embryo viability.•Sonographic assessment of HVBF may permit the prediction of superovulatory outcomes in ewes.
The aim of this study was to examine the association between antral follicular blood flow velocity and the response of ewes to hormonal ovarian superstimulation. Ten Santa Inês ewes were subjected to a short- (7days; Group 1) or long-term (13days; Group 2) progesterone (CIDR®; InterAg, Hamilton, New Zealand) priming, and a superovulatory treatment with porcine follicle-stimulating hormone (pFSH; Folltropin®-V; Bioniche Animal Health, Belleville, ON, Canada), given twice daily for four consecutive days in decreasing doses and initiated four or ten days after CIDR insertion, respectively. Embryos were recovered surgically seven days after the last pFSH dose. From one day prior to until the end of the pFSH regimen (Days −1 to 3), all ewes underwent daily transrectal ultrasonography of ovaries. The number of high-velocity pixels (HVPs; 0.055–0.11m/s or upper 50% of recordable velocities) on Day 1 correlated directly with the number of corpora lutea (CL; r=0.92, P=0.0002) and of viable embryos (r=0.77, P=0.01). Correlations were also recorded between the number of HVPs on Day 3 and the recovery rate (r=−0.69, P=0.03), viability rate (r=−0.64, P=0.05), and percentage of degenerated embryos (r=0.65, P=0.04). The percentage of HVPs relative to the total area of ovarian cross section on Day 1 was correlated with the number of CL (r=0.95, P<0.001) and of viable embryos (r=0.85, P=0.002). This parameter on Day 3 was also correlated with the recovery rate (r=−0.69, P=0.03). The percentage of HVPs relative to the total Doppler area on Day 0 was correlated with the recovery rate (r=0.72, P=0.02). It can be concluded that sonographic assessment of high-velocity antral follicular blood flow has the makings of a useful non-invasive method to predict the outcome of the superovulatory treatment in ewes.
OBJECTIVES: To evaluate the applicability of acoustic radiation force impulse elastography as a complementary method in diagnosing mammary neoplasia in dogs. METHODS: Mammary tumours from 50 female ...dogs were evaluated and divided into two groups: G1 (benign tissue) and G2 (malignant tumours). The nodules were assessed by B‐Mode ultrasonography, qualitative and quantitative acoustic radiation force impulse elastography and histopathology. RESULTS: B‐Mode ultrasound examination was ineffective at separating the tumours into the two groups. Likewise, there was no correlation between the grayscale images of the mammary tissue by qualitative elastography. A difference was found in the deformity of the mammary masses between the malignant and benign groups (P = 0 · 002). Using quantitative elastography, the mean values of shear velocity were 3 · 33 m/s for malignant tumours and 1 · 28 m/s for benign tissue (P < 0 · 0001). CLINICAL SIGNIFICANCE: The use of acoustic radiation force impulse elastography may help to differentiate between malignant and benign mammary neoplasms.
•Ultrasonographic attributes of the accessory sex organs and spectral Doppler indices of the internal illiac arteries (IIA) were determined in peri- and post-pubertal rams.•Morphometric and ...echotextural characteristics of accessory sex glands, hemodynamic indices of the IIA, and serum testosterone concentrations were examined for correlations with semen characteristics.•The attainment of sexual maturity in the rams was associated with an enlargement of the prostate and bulbourethral glands.•Echotextural attributes of vesicular and bulbourethral glands changed significantly between from the peri- to post-pubertal period.•Serum testosterone concentrations and hemodynamic indices of IIA were correlated with sperm progressive motility, vigor and the amount of ejaculate in rams.
The aim of the present study was to determine and compare ultrasonographic characteristics of accessory sex glands and spectral Doppler indices of the internal iliac arteries in peri- and post-pubertal rams raised in a subtropical climate. Forty-five Dorper rams were examined (24 rams aged 8–11 months and 21 rams aged 12–24 months). Digital images of all accessory sex glands were subjected to morphometric and echotextural analyses, the latter using commercially available image analytical software Image ProPlus®. Physical and morphological characteristics of semen and serum concentrations of testosterone were also determined. The dimensions of the prostate gland (12.9±1.2 compared with 14.2±2.7mm; mean±standard deviation) and bulbourethral glands (13.7±1.3 compared with 14.7±1.8mm) were greater (P=0.04) in sexually mature compared with peri-pubertal rams. Pixel intensity of vesicular (181.5±20.8 compared with 164.8±26.8, P=0.02) and bulbourethral gland parenchyma (166.9±16.9 compared with 141.8±29.1, P=0.001) was greater in peri-pubertal compared with sexually mature rams. Semen could be collected by ejaculation into the artificial vagina from 38% (8/21) of post-pubertal rams and 21% (5/24) of peri-pubertal animals (P=0.03). Semen volume was positively correlated with peak systolic velocity (PSV) and end-diastolic velocity (EDV) in the internal iliac arteries (r=0.79, P=0.001 and r=0.67, P=0.01, respectively), while spermatic vigor and progressive motility were inversely related to circulating concentrations of testosterone (r=−0.69, P=0.009 and r=−0.61, P=0.03, respectively). In summary, the attainment of sexual maturity in the rams of the present study was associated with an enlargement of the prostate and bulbourethral glands, and with the shift in echotextural attributes of vesicular and bulbourethral glands. Circulating testosterone concentrations and Doppler blood flow indices of the ram’s internal iliac arteries are significant predictors of sperm progressive motility, vigor and the amount of ejaculate.
PDF
