Rib Position Research Articles

Application of artificial intelligence to investigate the performance and flow pattern near staggered piece in V-ribs with aligned gaps roughness in solar air heater using relevant input parameters

The present work findings of an experimental investigation on a rectangular duct used in a solar air heater (SAH) to increase heat transfer and frictional characteristics and improve flow near the roughness. The rough SAH surface is created by staggered V-ribs and aligned gaps. For Reynolds numbers 3000–14,000, relative gap breadth (g/e) is changed from 2 to 5, while other parameters are maintained constant: relative roughness pitch (P/e) = 10, relative staggered rib position (P'/P) = 0.4, relative staggered rib size (w/g) = 1, and relative roughness height (e/Dh) = 0.0434. The Nusselt number (Nu) and friction factor (f) are found as 2.16 and 2.73 times higher than a flat plate under the identical operating and flow conditions. The overall augmented behavior of rough SAH considering frictional characteristics is calculated in terms of Thermal enhancement factor (TEF) as 1.56. The impact of gap width on flow pattern is examined by using ANSYS Academic Research CFD 15.0. ANN outperformed GMDH. The air mass flow rate was revealed to be the most sensitive influencing element in a sensitivity analysis.

Numerical investigation on thermal performance improvement of hydrogen-fueled tube with rib/fins for micro thermophotovoltaic

Combustion characteristics and thermal performance of pre-mixed hydrogen/air in micro tubes for micro-thermophotovoltaic are conducted under various operating conditions. To improve flame stability and energy efficiency, a cylindrical stepped tube with rib/fins is proposed. Effects of burner optimization on hydrogen-fueled flame regime, heat transmission and thermal performance are numerically conducted, which is verified by experimental tests. The results illustrate that the inserted rib and its location strongly modify the anchoring and propagation of premixed H2/air flame, resulting in the improvement of heat transfer and radiation temperature. Furthermore, the employment of outlet-fins modifies the flow field and enhances heat recirculation by utilization of hot exhausted gases. There exists a balance between the radiation temperature reduction and the radiation surface augment via the increment of chamber length. Meanwhile, the influence grades of chamber length, flow rate, outlet-fins number and rib position are ranked in turn based on the grey relational analysis. So, electrical power of combustor C33-7-10 is 0.77 W higher than that of stepped tube for a micro-TPV with InGaAsSb at mf = 5.10 × 10−5 kg/s, and it obtains a higher power output of 2.22 W at mf = 8.16 × 10−5 kg/s. It can also be further improved by the flow rate increment and employment of high efficiency PV cells.

Cross-sectional properties of rib geometry from an adult population.

Introduction: Human body models (HBMs) play a key role in improving modern vehicle safety systems to protect broad populations. However, their geometry is commonly derived from single individuals chosen to meet global anthropometric targets, thus their internal anatomy may not fully represent the HBM's target demographic. Past studies show sixth rib cross-sectional geometry differences between HBM ribs and population-derived ribs, and corrections to HBM ribs based on these data have improved HBM's abilities to predict rib fracture locations. Methods: We measure and report average and standard deviations (SDs) in rib cross-sectional geometric properties derived from live subject CT scans of 240 adults aged 18-90. Male and female results are given as functions of rib number and rib lengthwise position for ribs 2 through 11. Population means/SDs are reported for measures of rib total area, rib cortical bone area, and rib endosteal area, as well as inertial moment properties of these rib sections. These population corridors are compared between males and females, and against the baseline rib geometries defined in six current HBMs. Results: Total cross-sectional area results found average males ribs to be larger than those of females by between approximately 1-2 SDs depending on rib number and position, and larger in cortical bone cross-sectional area by between 0-1 SDs. Inertial moment ratios showed female ribs being between approximately 0-1 SDs more elongated than male ribs, dependent again on rib number and position. Rib cross-sectional areas from 5 of the 6 HBMs were found to be overly large along substantial portions of most ribs when compared to average population corridors. Similarly, rib aspect ratios in HBMs deviated from average population data by up to 3 SDs in regions towards sternal rib ends. Discussion: Overall, while most HBMs capture overall trends such as reductions in cross-section along shaft lengths, many also exhibit local variation that deviates from population trends. This study's results provide the first reference values for assessing the cross-sectional geometry of human ribs across a wide range of rib levels. Results also further provide clear guidelines to improve rib geometry definitions present in current HBMs in order to better represent their target demographic.

Milling force prediction of inclined rib with low rigidity in milling process of hollow thin-walled structural parts

In order to improve the prediction accuracy of low rigidity inclined rib milling force model in the milling process of hollow thin-walled structural parts, the static deformation of low rigidity inclined rib was solved by means of numerical analysis and finite element simulation method; moreover, the deformation mixed prediction model was established by combining general regression neural network with fruit fly optimization algorithm and cross validation algorithm to efficiently predict the dynamic deformation of low rigidity inclined rib under different parameters. Thereafter, based on this model, the dynamic feed per tooth solving model was established to predict the dynamic milling force, and it was verified by experiments. The results show that under the processing conditions of 6000 r/min, 0.14 mm/z, and 4 mm cutting width, the theoretical values of the maximum milling forces in X, Y, Z directions at the right diagonal rib position are 361 N, 788 N, and 229 N, respectively, and the experimental values are 398 N, 802 N, and 218 N, respectively. Under the processing conditions of 7000 r/min, 0.14 mm/z, and 3.5 mm cutting width, the theoretical values of the maximum milling forces in X, Y, Z directions at the right diagonal rib position are 361 N, 788 N, and 229 N, respectively, and the experimental values are 398 N, 802 N, and 218 N, respectively. The increase of cutting width leads to the increase of Y-direction force, besides, the increase of feed speed will lead to the increase of X-direction forces and Z-direction forces. The range of X-direction prediction error rate is 8.45–16.15%, Y-direction prediction error rate is 1.50–4.85%, Z-direction prediction error rate is 10.5–15.65%, and the milling force prediction error is kept below 16%.

Enhanced heat transfer of supercritical n-decane in cooling channels with triangular ribs for regenerative cooling

• A continuous ribbed channel is designed to enhance the cooling capacity. • The channel can provide up to 2.04 times superior heat transfer performance. • The insertion of ribs enhances the uniformity of buoyancy distribution. • The triangular rib channel improves axial temperature uniformity. • The mechanism of generating vortices in the slot is analysed. Regenerative cooling is regarded as an effective method for managing the heat of scramjet combustors, and the design of cooling channels is critical for removing more heat from the engine. A continuous triangular rib channel was proposed. The effects of rib position, height, and pitch on the heat transfer performance were investigated using Fluent 18.0. The SST k –ω turbulence model was used to study the thermal behaviour of supercritical n-decane in channels and showed good agreement with the experimental data. Results show that the insertion of triangular ribs at the bottom and top can reduce the bottom wall temperature by 243.8 K in the studied case. The triangular rib channel can provide up to 2.04 times superior heat transfer performance. The continuous triangular ribs significantly reduced axial temperature inhomogeneity. Local streamlines were studied to demonstrate the influence of rib parameters on the flow and heat transfer processes. A local heat transfer enhancement occurs when the rib has a large inclination. For the studied conditions, the generation of vortices was carefully evaluated, and it was found that the generation of vortices in the slot was related to the value of h / p .

A novel bone suppression algorithm in intensity-based 2D/3D image registration for real-time tumor motion monitoring: Development and phantom-based validation.

BackgroundReal‐time tumor motion monitoring (TMM) is a crucial process for intra‐fractional respiration management in lung cancer radiotherapy. Since the tumor can be partly or fully located behind the ribs, the TMM is challenging.PurposeThe aim of this work was to develop a bone suppression (BS) algorithm designed for real‐time 2D/3D marker‐less TMM to increase the visibility of the tumor when overlapping with bony structures and consequently to improve the accuracy of TMM.MethodA BS method was implemented in the in‐house developed software for ultrafast intensity‐based 2D/3D tumor registration (Fast Image‐based Registration [FIRE]). The method operates on both, digitally reconstructed radiograph (DRR) and intra‐fractional X‐ray images. The bony structures are derived from computed tomography data by thresholding during ray‐casting, and the resulting bone DRR is subtracted from intra‐fractional X‐ray images to obtain a soft‐tissue‐only image for subsequent tumor registration. The accuracy of TMM utilizing BS was evaluated within a retrospective phantom study with nine different 3D‐printed tumor phantoms placed in the in‐house developed Advanced Radiation DOSimetry (ARDOS) breathing phantom. A 24 mm craniocaudal tumor motion, including rib eclipses, was simulated, and X‐ray images were acquired on the Elekta Versa HD Linac in the lateral and posterior–anterior directions. An error assessment for BS images was evaluated with respect to the ground truth tumor position.ResultsA total error (root mean square error) of 0.87 ± 0.23 mm and 1.03 ± 0.26 mm was found for posterior–anterior and lateral imaging; the mean time for BS was 8.03 ± 1.54 ms. Without utilizing BS, TMM failed in all X‐ray images since the registration algorithm focused on the rib position due to the predominant intensity of this tissue within DRR and X‐ray images.ConclusionThe BS algorithm developed and implemented improved the accuracy, robustness, and stability of real‐time TMM in lung cancer in a phantom study, even in the case of rib interlude where normal tumor registration fails.

Morphological patterns of the rib cage and lung in the healthy and adolescent idiopathic scoliosis.

The morphology of the rib cage affects both the biomechanics of the upper body's musculoskeletal structure and the respiratory mechanics. This becomes particularly important when evaluating skeletal deformities, as in adolescent idiopathic scoliosis (AIS). The aim of this study was to identify morphological characteristics of the rib cage in relation to the lung in patients with non‐deformed and scoliotic spines. Computed tomography data of 40 patients without any visible spinal abnormalities (healthy group) and 21 patients with AIS were obtained retrospectively. All bony structures as well as the right and left lung were reconstructed using image segmentation. Morphological parameters were calculated based on the distances between characteristic morphological landmarks. These parameters included the rib position, length, and area, the rib cage depth and width, and the rib inclination angle on either side, as well as the spinal height and length. Furthermore, we determined the left and right lung volumes, and the area of contact between the rib cage and lung. Differences between healthy and scoliotic spines were statistically analysed using the t‐test for unpaired data. The rib cage of the AIS group was significantly deformed in the dorso‐ventral and medio‐lateral directions. The anatomical proximity of the lung to the ribs was nearly symmetrical in the healthy group. By contrast, within the AIS group, the lung covered a significantly greater area on the left side of the rib cage at large thoracic deformities. Within the levels T1–T6, no significant difference in the rib length, depth to width relationship, or area was observed between the healthy and AIS groups. Inferior to the lung (T7–T12), these parameters exhibited greater variability. The ratio between the width of the rib cage at T6 and the thoracic spinal height (T1–T12) was significantly increased within the thoracic AIS group (1.1 ± 0.08) compared with the healthy group (1.0 ± 0.05). No statistical differences were found between the lung volumes among all the groups. While the rib cage was frequently strongly deformed in the AIS group, the lung and its surrounding ribs appeared to be normally developed. The observed rib hump in AIS appeared to be formed particularly by a more ventral position of the ribs on the concave side. Furthermore, the rib cage width to spinal height ratio suggested that the spinal height of the thoracic AIS‐spine is reduced. This indicates that the spine would gain its growth‐related height after correcting the spinal deformity. These are the important aspects to consider in the aetiology research and orthopaedic treatment of AIS.

Film cooling characteristics of cross-flow coolant passage with various relative positions of holes and inclined ribs

To investigate the application of ribbed cross-flow coolant channels with film hole effusion and the effects of the internal cooling configuration on film cooling, experimental and numerical studies are conducted on the effect of the relative position of the film holes and different orientation ribs on the film cooling performance. Three cases of the relative position of the film holes and different orientation ribs (post-rib, centered, and pre-rib) in two ribbed cross-flow channels (135° and 45° orientation ribs) are investigated. The film cooling performances are measured under three blowing ratios by the transient liquid crystal measurement technique. A RANS simulation with the realizable k-ε turbulence model and enhanced wall treatment is performed. The results show that the cooling effectiveness and the downstream heat transfer coefficient for the 135° rib are basically the same in the three position cases, and the differences between the local effectiveness average values for the three are no more than 0.04. The differences between the heat transfer coefficients are no more than 0.1. The “pre-rib” and “centered” cases are studied for the 45° rib, and the position of the structures has little effect on the film cooling performance. As the film hole moves backward relative to the rib position (from the pre-rib to the post-rib), the swirling flow formed in the hole has a slight difference, and the discharge coefficient of the film hole increases slightly at lower blowing ratio while decreases slightly at higher blowing ratio. In the different position cases, the outlet velocity distribution of the film holes, the jet pattern and the discharge coefficient are consistent with the variation in the cross flow.

Optimization of artificial roughness parameters in a solar air heater duct roughened with hybrid ribs

The article presents experimental and computational investigation of solar air heater using hybrid configuration of broken arc and staggered rib for heat transfer enhancement. The performance of the solar air heater is investigated through a series of experimental trials by varying flow and geometrical parameters like non-dimensional staggered rib position (0.2–0.8), roughness pitch (4–12), gap width (0.5–2.5), gap position (0.2–0.8), roughness height (0.022–0.043), arc angle (15°-75°), staggered rib piece size (1–6), and Reynolds number(2000–16000). The impact of staggered rib on the fluid flow pattern has been observed using numerical approach based on Finite volume method. The proposed design increases the friction factor & Nusselt number by 2.57 and 3.16 times respectively in comparison with a smooth duct. Moreover, the Nusselt number augments by 1.22 times in comparison with broken arc rib. The optimum values of both the flow and geometric parameters are evaluated and empirical correlations for pressure loss & Nusselt number are also reported. It is concluded that the thermal–hydraulic performance of the proposed hybrid rib roughness (2.33) is found to be superior in comparison with similar rib roughness geometries.

Fully Automatic Sliding Motion Compensated and Simultaneous 4D-CBCT via Bilateral Filtering.

PurposeTo incorporate the bilateral filtering into the Deformable Vector Field (DVF) based 4D-CBCT reconstruction for realizing a fully automatic sliding motion compensated 4D-CBCT.Materials and MethodsInitially, a motion compensated simultaneous algebraic reconstruction technique (mSART) is used to generate a high quality reference phase (e.g. 0% phase) by using all phase projections together with the initial 4D-DVFs. The initial 4D-DVF were generated via Demons registration between 0% phase and each other phase image. The 4D-DVF will then kept updating by matching the forward projection of the deformed high quality 0% phase with the measured projection of the target phase. The loss function during this optimization contains an projection intensity difference matching criterion plus a DVF smoothing constrain term. We introduce a bilateral filtering kernel into the DVF constrain term to estimate the sliding motion automatically. The bilateral filtering kernel contains three sub-kernels: 1) an spatial domain Guassian kernel; 2) an image intensity domain Guassian kernel; and 3) a DVF domain Guassian kernel. By choosing suitable kernel variances, the sliding motion can be extracted. A non-linear conjugate gradient optimizer was used. We validated the algorithm on a non-uniform rotational B-spline based cardiac-torso (NCAT) phantom and four anonymous patient data. For quantification, we used: 1) the Root-Mean-Square-Error (RMSE) together with the Maximum-Error (MaxE); 2) the Dice coefficient of the extracted lung contour from the final reconstructed images and 3) the relative reconstruction error (RE) to evaluate the algorithm's performance.ResultsFor NCAT phantom, the motion trajectory's RMSE/MaxE are 0.796/1.02 mm for bilateral filtering reconstruction; and 2.704/4.08 mm for original reconstruction. For patient pilot study, the 4D-Dice coefficient obtained with bilateral filtering are consistently higher than that without bilateral filtering. Meantime several image content such as the rib position, the heart edge definition, the fibrous structures all has been better corrected with bilateral filtering.ConclusionWe developed a bilateral filtering based fully automatic sliding motion compensated 4D-CBCT scheme. Both digital phantom and initial patient pilot studies confirmed the improved motion estimation and image reconstruction ability. It can be used as a 4D-CBCT image guidance tool for lung SBRT treatment.

Real-Time Ultrasonic Evaluation Of Swine

This study shows no difference in the backfat data collected on live and dead animals. In adjusted data, barrows had more backfat according to sonic and actual carcass measurement. There was a significantly (P<0.05) lower value in gilts in the first and last rib positions and in barrows in all positions but the tenth rib for sonic data as compared with carcass measurement. A high and significant (P<0.01) correlation existed between sonic and carcass measurements of fat thickness across sex. Within each sex, correlation was highest on the tenth rib followed by the last rib in gilts and the last lumbar in barrows. There were no significant differences in longissimus area measurement taken ultrasonically or in the carcass although correlations between them were high, being higher in gilts. 3MHz scanning produced greater accuracy in gilts than barrows for fat thickness and longissimus area determination, 5MHz, however, gave data that were closer correlated with carcass data. Except for the first rib position, there were no differences between scans taken on the hot carcass and actual carcass measures taken on the chilled right and left sides 48h later. The result suggests that hogs can be scanned a forthnight before slaughter and the data can be used in computing hog carcass yield at the point of sale. It also suggests the possibility of complete grading for hot carcasses and may further encourage hot processing if adopted. In cold processing situation, it may remove the necessity to enter the cooler for carcass measures.

Determining Relationships between Marbling Scores and Carcass Yield Traits of German Beef Bull Carcasses Using Video-Image Analysis at the 12th and 10th Rib Position of Longissimus Thoracis and EUROP Classification

In contrast to other international beef classification systems, the European EUROP system disregards marbling in meat quality assessment. Instead, it focuses primarily on the assessment of conformation and fat score. Due to the lack of more specific assessment, beef quality in Germany is less known than beef produced in other countries and is largely incomparable to international standards. The aim of this study was to explore the potential of video-image analysis (VIA) for the assessment of bull carcasses for the commercial beef market in Germany. Marbling scores and carcass traits of 170 carcasses were assessed at the 10th/11th and 12th/13th rib-eye sections of longissimus thoracis. Results showed that VIA is able to precisely assess marbling scores at a German cutting position with a close relation (r = 0.83) to the US position. Furthermore, carcass traits integral to the US Yield Grade, such as rib fat (mean 112 mm) and a modified trait of fat/meat ratio, were assessed at the 10th/11th rib-eye position in a process reliably corresponding to the US position (mean 98 mm). EUROP traits showed only weak relationships with marbling scores, VIA measured rib fat thickness, and carcass weights. Although complete validation of video image analysis requires further research with a higher number of test animals, VIA is a viable tool for classifying the variation of German beef carcasses more reliably during the slaughter line and it could valuably supplement EUROP classification traits.

Effects of novel hybrid nanofluid (TiO2–Cu/EG) and geometrical parameters of triangular rib mounted in a duct on heat transfer and flow characteristics

Heat transfer and flow characteristics have been numerically analyzed by using four different fluids [pure ethylene glycol (EG), TiO2/EG and Cu/EG nanofluids and 50%:50% TiO2–Cu/EG hybrid nanofluid] and changing the position, length and height of a triangular rib placed in a two-dimensional duct under forced convection and turbulent flow conditions using RNG k-epsilon turbulence model. While forming the hybrid nanofluid, all nanoparticles are added at 50–50%. A constant heat flux of 500 W m−2 is applied to the bottom wall of the duct. The Reynolds number is considered in the range of 50,000 and 100,000. Two different nanoparticle volume fractions, 1.0% and 4.0%, are used. The parameters of the rib are dimensionlized, and three different rib positions (X/H = 1, 3 and 5), lengths (S/H = 0.5, 1 and 1.5) and heights (h/H = 0.1, 0.2 and 0.3) are used. Governing equations are determined with the finite volume method. In the study, analysis of Nusselt number, Darcy friction factor (f), PEC number and velocity streamlines is performed in detail. Generally, heat transfer performance increases with increasing Reynolds number and nanoparticle volume fraction, but the increase in nanoparticle volume fraction also increases the Darcy friction factor. TiO2–Cu/EG hybrid nanofluid having the 4.0% nanoparticle volume fraction is the best heat transfer fluid. When using TiO2–Cu/EG hybrid nanofluid, the increase in the PEC number varies between 8 and 30% in the smooth duct. From the results obtained by using hybrid nanofluid in the duct with the triangular rib, it is understood that the rate of heat transfer enhances with increasing dimensionless rib position, length and height. But the most effective parameter of these is change in the rib height. The most suitable fluid for the study is TiO2–Cu/EG hybrid nanofluid with 4.0% nanoparticle volume fraction, and the most favorable rib parameters are rib height of h/H = 0.3, rib length of S/H = 1.5 and rib position of X/H = 5.

Composite wing flutter analysis with variations of ribs location

Elastic structures constructed using composite materials may be easily deformed due to low stiffness, leading to flutter phenomenon to occur during flight. In this paper, the occurrence of flutter on a composite UAV wing is investigated by considering the effect of the location and position of ribs on flutter speed. Flutter analyses are conducted using the full aeroelastic equation of motion derived from the Lagrange's equation and Theodorsen's airfoil theory. UTM CAMAR UAV composite wings are selected as case studies in which the ribs are positioned across the wing span to obtain the optimized rib position. The natural frequencies for bending and torsion at each of the rib positions is obtained using the finite element analysis, conducted using the ABAQUS software. From the study, a pair of ribs located at 33% and 67% of wing span was found to give the maximum flutter speed at 264.62 m/s.

Exploring the Benefits of Annular Rectangular Rib for Enhancing Thermal Efficiency of Nonpremixed Micro-Combustor

Micro-combustor can provide the required thermal energy of micro-thermal photovoltaic (MTPV) systems. The performance of MTPV is greatly affected by the effectiveness of a micro-combustor. In this study, a numerical simulation was conducted to explore the benefits of annular rectangular rib for enhancing the thermal performance of a nonpremixed micro-combustor. Based on the investigations under various rib heights, rib positions, and inlet mass flow rates, it is found that the addition of annular rectangular ribs in the micro-combustor creates a turbulent zone in the combustion chamber, thereby enhancing the heat transfer efficiency between the inner wall of the combustion chamber and the burned gas. The micro-combustor with annular rectangular rib shows a higher and more uniform wall temperature. When the H2 mass flow is 7.438 × 10−8 kg/s and the air mass flow is 2.576 × 10−6 kg/s, the optimum dimensionless rib position is at l = 6/9 and r = 0.4. At this condition, the micro-combustor has the most effective and uniform heat transfer performance and shows significant decreases in entropy generation and exergy destruction. However, the optimum l and r significantly depend on the inlet mass flow of H2/air mixture.

An experimental heat transfer investigation of an impingement jet array with turbulators on both target plate and impingement plate

Impingement cooling has been widely used for high heat transfer demanded applications, and numerous attempts have been made to improve its thermal efficiency. This study presents experimental heat transfer results of an innovative rib configuration combined by V-ribs on the impingement plate and detached ribs on the target plate for an inline impingement system. The combined ribs are expected to redirect the spent air in the impingement channel, modify the cross-flow field and thus, improve the heat transfer performance. The transient thermochromic liquid crystal (TLC) method is employed for detailed heat transfer measurements. Pressure taps set along the test rig are used to evaluate the pressure loss. In addition, the thickness and roughness effect of the sprayed coating layers (TLC and black paint) is experimentally studied. The detached rib configuration is determined based on a geometrical parameter study on the rib position. The effect of the combined ribs is investigated for different jet Reynolds numbers and different separation distances. The results show that the combined ribs induce a Nusselt number increase for all cases in the studied range, with a negligible extra pressure loss. A relatively thin and smooth sprayed coating is employed, to ensure the measurement accuracy.

Bending analysis of skew ribbed plates with a meshfree method

Based on the first - order shear deformation theory (FSDT), a meshless method for solving the free vibration problem of the skew ribbed plates is proposed. The plates and ribs are discretized with a series of points to obtain a meshless model of the ribbed plate by simulating the ribs with beams. The FSDT and the moving least - squares approximation are used to establish the displacement field. The displacement fields of the stiffener can be expressed in terms of the mid-surface displacement of the plate by imposing displacement compatible conditions between the plate and the stiffener. Then the stiffness equation of the entire skew ribbed plate can be derived by superimposing the strain energy of plate and stiffener. And the boundary condition is introduced by the full transformation method. Several examples are calculated, and the results given by the proposed method are compared with those from other researchers or ABAQUS. The results show that the method can effectively analyze the bending problem of the skew ribbed plate, and it avoids redistribution of plate nodes when rib position changes.

Investigation of the Reliability of Saddle Fitters to Determine the Position of the Last Thoracic Vertebra of Horses Using Palpation Techniques: A Pilot Study

Published guidelines indicate an English saddle tree should not extend beyond the 18th thoracic vertebra (T18). The study aimed to assess reliability of saddle fitters (SFs) to identify the T18 spinous process (SP). Part 1 investigated agreement between T18 (T18SF) as identified by three SFs using palpation and a veterinary surgeon (VS) using radiography (T18VS) in seven horses. Saddle fitter 1 and SF2 palpated the lumbosacral joint and counted cranially six SPs, whereas SF3 followed the rib curvature toward the dorsal midline. In part 2, SF1 and SF2 identified T18 by counting cranially five SPs in seven horses on two occasions. Agreement between SFs and VS was assessed using t tests and Bland-Altman plots. Interrater and intrarater reliability were estimated using intraclass correlation coefficients. In part 1, SF1 and SF2 found T18SF 4.3 cm (±4.1 and 4.0 cm, respectively) cranial to T18VS. Mean difference between T18SF3 and T18VS was 0.1 ± 4.9 cm (95% CI: −9.5 cm, 9.6 cm, P = .976). When counting cranially five SPs, mean difference between T18SF1 and T18VS was −1.5 ± 3.4 cm (95% CI: −8.3 cm; 5.1 cm; P = .265) and T18SF2 and T18VS was −0.3 cm ± 4.5 cm (95% CI: −8.8 cm; 8.5 cm; P = .847). Interrater reliability was “good” (ICC = 0.798). Intrarater reliability was “excellent” for SF1 (ICC = 0.905) and “good” for SF2 (ICC = 0.847). Counting cranially five SPs from the lumbosacral joint, when coupled with observation of the rib position and curvature should ensure a saddle is not placed beyond T18.

Flow Structure and Heat Transfer of Jet Impingement on a Rib-Roughened Flat Plate

The jet impingement technique is an effective method to achieve a high heat transfer rate and is widely used in industry. Enhancing the heat transfer rate even minimally will improve the performance of many engineering systems and applications. In this numerical study, the convective heat transfer process between orthogonal air jet impingement on a smooth, horizontal surface and a roughened uniformly heated flat plate is studied. The roughness element takes the form of a circular rib of square cross-section positioned at different radii around the stagnation point. At each location, the effect of the roughness element on heat transfer rate was simulated for six different heights and the optimum rib location and rib dimension determined. The average Nusselt number has been evaluated within and beyond the stagnation region to better quantify the heat transfer advantages of ribbed surfaces over smooth surfaces. The results showed both flow and heat transfer features vary significantly with rib dimension and location on the heated surface. This variation in the streamwise direction included both augmentation and decrease in heat transfer rate when compared to the baseline no-rib case. The enhancement in normalized averaged Nusselt number obtained by placing the rib at the most optimum radial location R/D = 2 was 15.6% compared to the baseline case. It was also found that the maximum average Nusselt number for each location was achieved when the rib height was close to the corresponding boundary layer thickness of the smooth surface at the same rib position.

Analysis of carcass characteristics and fat deposition of Merino, South African Mutton Merino and Dorper lambs housed in a feedlot

The objective of this study was to determine the effect of time spent in a feedlot on the size of the various fat depots and the distribution of the main tissues (muscle, bone, and fat) of three common South African sheep breeds. Lambs were supplied with a balanced diet (16% protein, 10 MJ ME/kg feed) ad libitum and had free access to water. Lambs from each breed were divided into six groups, which were slaughtered at 21-day intervals until a production period of 105 days had been reached. During carcass dressing, visceral and renal fat was removed and expressed as a percentage of carcass weight. The subcutaneous fat (SCF) depth was measured on the longissimus lumborum at the 13th rib position using an electronic calliper. The proportion of muscle, bone and fat was determined by dissecting a three-rib cut made on the prime rib between the 9th and 11th ribs. The percentage of visceral and renal fat increased throughout the production period for all breeds. The percentage of renal fat was up to 2.9% higher than the percentage visceral fat in both SAMM production groups. Dorper lambs tended to have high SCF levels (5.6 mm fat after 42 days) due to the early maturing nature of the breed. They reached a maximum fat depth of 20.4 mm fat after 105 days. The SAMM lambs tended to deposit SCF at a slower rate and the late maturing Merino breed was found to be much leaner, and did not reach the high fat levels of the SAMM or Dorper lambs. The percentage of muscle and bone in all carcasses decreased with an increase in the number of days in the feedlot, while the percentage of carcass fat increased during this period. The increase in late maturing adipose tissue in all breeds as they become older is amplified by the restricted movement in the feedlot and high energy diet that the lambs receive.