Number Of Rib Research Articles

Experimental investigation on cooling performance and heat transfer characteristics of the ribbed endwall with upstream leakage

In this paper, the merits and demerits of endwall modification by designing micro-scale ribs onto the turbine endwall surface was examined experimentally for two aspects: cooling performance and heat transfer characteristics. The experiment was conducted on ribbed endwall with three rib directions (horizontal, vertical and tiled rib) and two rib spacings (8 mm and 10 mm) and compared with the flat endwall. The measurement of heat transfer was conducted with a high-resolution infrared thermal camera and that of cooling effectiveness (η) was conducted with pressure-sensitive paint technique. Results showed that the direction of rib and rib-induced vortex greatly affects the coverage of coolant, which the tilted and vertical ribbed endwall demonstrated positive effects on film cooling. Additionally, the heat transfer of the ribbed endwall is also connected with the layout of the rib and mainly depends on the joint influence of the rib-induced vortex and passage vortex. The Nusselt number (Nu) of the vertical rib was the smallest. In general, vertical rib with larger rib spacing shows the comprehensive performance, that an increase of 9.5% for area-averaged η than original endwall with mass flow rate of 1.0% and the least increase of Nu, which can provide guidelines for future cooling design.

Mechanical properties and failure patterns of sandwich panels with AR-glass textile reinforced concrete face sheets subjected to quasi-static load

A sandwich panel was prepared with Alkali Resistant-glass textile reinforced concrete (ARG-TRC) as the face sheet and Expanded Polystyrene (EPS) granular mortar as the core in this paper. Afterward, a quasi-static bending test was conducted to investigate the influences of the number of reinforcement layer, core thickness, and interface rib on the bending behaviors and failure of ARG-TRC sandwich panels (ARG-TRC-SPs). On this basis, the elastic bending deformation and ultimate bending capacity were theoretically predicted, and the failure mechanism was analyzed. The results show that ARG-TRC-SPs exhibited three common failure modes: face sheet bending fracture, core shear, and core crushing. Increasing the reinforcement layers significantly improved the properties of ARG-TRC-SPs but decreased textile utilization. Although the enhancement of the interface rib was dependent on the number of reinforcement layers, it could improve the integrity of ARG-TRC-SPs. There was a suitable core thickness for the ARG-TRC-SPs, and a thicker core did not indicate better mechanical properties. The theoretically predicted elastic deformation and ultimate bending capacity were in good agreement with the test results. However, the contribution of the core and interface ribs was underestimated. These results can provide a valuable reference for researchers and engineers in designing and applying TRC-SPs.

Thermal Field Simulation and Thermal Capacity Influence Factor Analysis of Disc Brake Based on Thermal-structure Coupling

The matching and heat dissipation capacity of the brake have an important impact on the braking performance of the vehicle. During braking, most of the driving kinetic energy of the vehicle is converted into the internal energy of the brake disc through friction heat generation, resulting in a quick rise in the temperature of the brake disc, thus causing a complex thermal-solid coupling problem. This paper takes the disc brake of a certain vehicle as the analysis object, establishes the finite element model of the disc brake through hypermesh, and analyzes the distribution characteristics of the contact pressure between the friction pad and the brake disc under clamping and torsion braking behaviors. A thermal-solid coupling simulation analysis method considering the actual heat flow and heat transfer boundary of the brake disc is proposed. Compared with the temperature field of the bench test, the simulation accuracy reaches 97%. Finally, three types of brake discs with point rib, rotation rib and straight rib are designed, and the influence of brake disc thickness, shape and number of ventilation rib on the thermal capacity of brake disc is analysed. It provides guidance for the structural design of brake discs and can replace partial tests and shorten the brake disc development cycle.

Experimental investigation for heat and flow characteristics of solar air heater having symmetrical gaps in multiple-arc rib pattern as roughness elements

ABSTRACT The working medium is air in a solar air heater (SAH) and because of its low heat-transfer coefficient, SAH results in poor performance. By placing artificial-roughness over the heat-collector plate, the performance of a SAH can be improved significantly. The improvement in thermal and hydraulic performance by providing multiple-arc-rib roughnesses patterns with the gap is discussed and generalized correlations are developed for Nusselt number and friction factor based on results collected from the experimentation (under steady condition). In total seven parameters were considered to study heat transfer and friction characteristics, that is, Reynolds number, rib-pitch, rib-height, number of gaps, arc-attack angle, rib, and gap width. In comparison to smooth collector-plate type of solar air heater, the 5.76 and 6.05 times higher Nusselt number and friction factor obtained in the proposed roughened SAH. Besides this, the developed mathematical expression for Nusselt number and friction factor shows close-fit with the experimental data under the error band of only 10 and 12%, respectively.

Factors influencing frequency of resuscitation-related injuries in the Emergency care service of Ljubljana during implementation of the ERC resuscitation guidelines 2015

Purpose of the study: General opinion that at least 1/3 of resuscitated patients sustain rib fractures and at least 1/5 sternum fractures was mainly based on autopsy studies conducted in the twentieth century, when lower chest compression depths and rates were recommended and mainly manual chest compressions performed. However, recent autopsy and radiological studies report on much higher frequencies of such injuries. Increasing use of the LUCAS™ device (mechanical CPR) raises a question whether it has adverse effects. Therefore, we analysed the influence of age, gender, resuscitation time and mode of CPR (manual vs. mechanical) on the incidence and number of rib and sternum fractures.

Analisis Frekuensi Pribadi Dan Modus Getar Struktur Pesawat Tanpa Awak Tipe Flying Wings

One of the important consideration in designing an unmanned aerial vehicle (UAV) is the dynamics characteristic of UAV structure. The dynamics characteristic of UAV structure can be evaluated from its dynamic parameters such as : natural frequencies and mode shape. These parameters play an important role in determining the system’s dynamic response. In general, a low stiffness structure is more sensitive to the dynamic load in comparison with a high stiffness structure. In this research, modification UAV structural stiffness is conducted by varying rib and spar number and configuration on UAV wing. Evaluation of rib and spar number and configuration effect to the natural frequency and mode shape of UAV structure is conducted numerically and experimentally. The simulation results show that the natural frequencies increases with increasing of the number of spar and decreases with decreasing of the number of rib.

Is the number of rib fractures a risk factor for delayed complications? A case-control study.

To analyse factors that may predict the appearance of rib fracture complications during the first days of evolution and determine whether the number of fractures is related to these complications. Retrospective case-control study of patients admitted with a diagnosis of rib fractures between 2010 and 2014. Two groups were established depending on the appearance or not of pleuropulmonary complications in the first 72h, and the following were compared: age, sex, Charlson comorbidity index (CCI), number and uni- or bilateral involvement, mechanism of trauma, days of hospital stay, haemoglobin on discharge minus haemoglobin on admission, pleuropulmonary complications during admission (pneumothorax, haemothorax or pulmonary contusion) and placement of pleural drainage. One hundred and forty-one cases of rib fractures were admitted in the period mentioned. There were no differences in the patients' baseline characteristics (age, sex and Charlson Comorbidity Index) between the two groups. Differences were found in the number of fractures (2.98 ± 1.19 in the group without complications vs 3.55 ± 1.33 in the group with complications, p = 0.05) and in the drop in the level of haemoglobin (0.52 ± 0.91mg/dl vs 1.22 ± 1.29mg/dl, p = 0.01). The length of hospital stay varied considerably in each group (5.35 ± 4.05 days vs 7.86 ± 6.96 days), but without statistical significance (p = 0.11). The number of fractured ribs that best predicted the appearance of complications (delayed pleuropulmonary complications and greater bleeding) was 3 or more.

Parametric study on a novel grouted rolling pipe splice for precast concrete construction

Grout-filled mechanical splice system, with its remarkable ability to connect precast elements, is one of the most important technologies for precast concrete construction. However, for the time being, its high cost has hindered the implementation of precast concrete structures to a certain degree in developing countries. This paper presents a new type of grouted sleeve which can be easily and economically fabricated with a standard seamless steel pipe through cold rolling techniques. Utilizing this sleeve, 69 sets of coupler specimens were prepared considering parameters of inner cavity structure and cross-sectional dimension of sleeve, grout strength, and diameter and embedded length of steel bar. Through direct pullout test, it is shown that the proposed splice is capable of developing of 100% of ultimate strength of the bar providing an embedded length of 6 times bar diameter. Increasing the number and height of inner concentric rib which rolled on the sleeve only in inelastic segment is an effective technique to improve the bond strength of the splice. With the increment of the ribs, clearly different effects of sleeve dimension and grout cylinder thickness on the bond strength can be observed due to different confining mechanism. Finally, a design method for the novel deformed grouted splice sleeve is proposed.

A NUMERICAL STUDY ON CORRELATION OF RIB FRACTURES WITH THORACIC INJURY CRITERIA IN OBLIQUE IMPACT

Thoracic injury is one of the vital issues in vehicle side crashes. Experiments have been done widely to study thoracic injuries using biological subjects but less virtual tests were made by using Finite Element (FE) models. This study aimed at determining the correlation of the computationally calculated thoracic injury (Number of Rib Fractures NRF) with existing thoracic injury criteria under pure side and oblique impacts. For this purpose, a previously developed thorax FE model was validated by using Post Mortem Human Subject (PMHS) tests in pure side and oblique impacts in this study. The rib fractures were reconstructed and compared with the fractures observed in the PMHS tests. The model was then used to simulate rib fractures in human thorax impactor tests at Principal Direction of Force (PDOF) angles of 90[Formula: see text] to 35[Formula: see text] (total of 12 impacts). Furthermore, the normalized NRF were calculated and analyzed for comparing with normalized simulated injury parameters based on various human thoracic injury criteria, including contact force criterion, thorax deflection criterion, compression criterion, upper spine acceleration criterion and Thoracic Trauma Index (TTI). It is suggested that the TTI criterion has better correlation with the NRF than the other injury criteria.

Genetic parameters for various growth, carcass and meat quality traits in a New Zealand sheep population

Meat quality and carcass characteristics are becoming more relevant for the sheep breeding programs because of their economic value. Understanding the genetic basis for these traits and its relationship with standard traits is necessary for this to be accomplished. Genetic and phenotypic parameters were estimated for 33 growth, carcass and meat quality traits using a large and unique data set from a variety of terminal sire sheep breeds and composites. This is the most comprehensive study to date of genetic parameter estimates for carcass and meat quality traits in New Zealand sheep and includes many traits that are difficult or expensive to measure and novel traits such as number of rib pairs.Heritability estimates ranged from 0.01 for meat redness at 168h after display to 0.44 for ultrasonic eye muscle depth. Most genetic correlations among growth and carcass traits were favourable and moderate to high. However, some genetic antagonisms such as those between carcass fatness and carcass weight were observed indicating that selection to produce heavier carcasses would also result in fatter carcasses. The genetic correlations among meat quality traits were quite variable. Marbling and tenderness were favourably but weakly genetically correlated, indicating that indirect selection gains by selecting only for traditional traits (i.e. growth and carcass traits) would be small and it is recommended that both be included in a breeding program in order to make greater genetic progress in these traits. The genetic correlations among growth/carcass and eating quality traits were moderate to low; however, some genetic antagonisms were observed, such as carcass fatness with marbling and meat redness, indicating that a stronger emphasis on selection for leanness could affect meat quality traits and consequently consumer eating satisfaction.The heritability estimates and phenotypic variances for the carcass and meat quality traits of New Zealand sheep populations suggest that most traits, apart from pH and meat yellowness, have sufficient phenotypic and genetic variation to enable substantial genetic gains to be achieved through selection. The genetic parameters presented in this study provide a valuable reference to design and/or update a terminal sire breeding program emphasizing meat quality traits. It is important to note that unfavourable genetic correlations identified in this study were low to moderate in magnitude, making it practical to select for favourable genetic progress in all traits or at least to maintain commercially acceptable levels for some traits, if they are measured and balanced in a selection index.

Reply to Letter: Frequency and number of resuscitation related rib and sternum fractures are higher than generally considered

We thank you for forwarding to us the letter received from Kralj E. et al. concerning our recent editorial considering the frequency and number of resuscitation related rib and sternum fractures (Resuscitation 2015; 93: A1–A2). They have drawn to our attention an unintentional error in the editorial, which suggests that the frequency of rib fractures observed in their study was similar to that previously reported. This is clearly not the case. The error arose from misunderstanding the conclusion of this study in the abstract, which states “It is generally considered that at least 1/3 of resuscitated patients sustain rib fractures and at least 1/5 sustain sternum fractures”. This is not a conclusion drawn from their study but, as we understand it, a general observation drawn from previously published work used to illustrate the new knowledge obtained from their study.We apologise to the authors of the most recent paper for this unintentional error, which is corrected by their letter.In making this apology we are pleased that we both agree as regards the wide variation of rib and sternal fracture rates at autopsy and the potential use of Post-Mortem CT scanning (PMCT) to improve future knowledge within this field.Conflict of interest statementNo conflicts of interest to declare. We thank you for forwarding to us the letter received from Kralj E. et al. concerning our recent editorial considering the frequency and number of resuscitation related rib and sternum fractures (Resuscitation 2015; 93: A1–A2). They have drawn to our attention an unintentional error in the editorial, which suggests that the frequency of rib fractures observed in their study was similar to that previously reported. This is clearly not the case. The error arose from misunderstanding the conclusion of this study in the abstract, which states “It is generally considered that at least 1/3 of resuscitated patients sustain rib fractures and at least 1/5 sustain sternum fractures”. This is not a conclusion drawn from their study but, as we understand it, a general observation drawn from previously published work used to illustrate the new knowledge obtained from their study. We apologise to the authors of the most recent paper for this unintentional error, which is corrected by their letter. In making this apology we are pleased that we both agree as regards the wide variation of rib and sternal fracture rates at autopsy and the potential use of Post-Mortem CT scanning (PMCT) to improve future knowledge within this field. Conflict of interest statementNo conflicts of interest to declare. No conflicts of interest to declare.

CPR-related rib and sternum fractures after unsuccessful resuscitation by means of manual or mechanical chest compressions with the LUCAS™ device

Purpose of the study: The reported incidence of rib and sternum fractures after unsuccessful cardiopulmonary resuscitation by manual chest compressions (manual CPR) in the twentieth century varied greatly, and it was generally considered that at least 1/3 of resuscitated patients sustained rib fractures and at least 1/5 sternum fractures. However, recent studies indicate amuch higher incidence of such injuries. Increasing use of the LUCASTM device (mechanical CPR) raises the question of whether it has any adverse effects. Our goal was to compare the incidence and number of rib and sternum fractures after manual and mechanical CPR. Materials and methods: This retrospective autopsy study included 946 patients (802 manual CPR and 144 mechanical CPR) resuscitated in the period 2011–2014, i.e., when Guidelines 2010 were applied. Results: At least one rib fracture was found in 86.9% of the patients resuscitated manually and in 88.9% of those resuscitated mechanically (p=0.512). Sternum fractures were found in 64.2% of the patients resuscitated manually and in 72.9% of those resuscitated mechanically (p=0.043). Either rib or sternum fractures or both were found in 88.8% of the patients in the manual CPR group and 93.1% of the patients in the mechanical CPR group (p=0.854). The average number of rib and sternum fractures per injured patient was 12.04 in the manual CPR group and 11.88 in the mechanical CPR group. Conclusion: In the studied population, mechanical CPR caused approximately 4% more rib and/or sternum fractures than manual CPR. However, the average number of fractures per injured patient was slightly lower in the mechanical CPR group.1,2

Using transpulmonary thermodilution leads successful fluid resuscitation in early phase of septic shock

Purpose of the study: The reported incidence of rib and sternum fractures after unsuccessful cardiopulmonary resuscitation by manual chest compressions (manual CPR) in the twentieth century varied greatly, and it was generally considered that at least 1/3 of resuscitated patients sustained rib fractures and at least 1/5 sternum fractures. However, recent studies indicate amuch higher incidence of such injuries. Increasing use of the LUCASTM device (mechanical CPR) raises the question of whether it has any adverse effects. Our goal was to compare the incidence and number of rib and sternum fractures after manual and mechanical CPR. Materials and methods: This retrospective autopsy study included 946 patients (802 manual CPR and 144 mechanical CPR) resuscitated in the period 2011–2014, i.e., when Guidelines 2010 were applied. Results: At least one rib fracture was found in 86.9% of the patients resuscitated manually and in 88.9% of those resuscitated mechanically (p=0.512). Sternum fractures were found in 64.2% of the patients resuscitated manually and in 72.9% of those resuscitated mechanically (p=0.043). Either rib or sternum fractures or both were found in 88.8% of the patients in the manual CPR group and 93.1% of the patients in the mechanical CPR group (p=0.854). The average number of rib and sternum fractures per injured patient was 12.04 in the manual CPR group and 11.88 in the mechanical CPR group. Conclusion: In the studied population, mechanical CPR caused approximately 4% more rib and/or sternum fractures than manual CPR. However, the average number of fractures per injured patient was slightly lower in the mechanical CPR group.1,2

Numerical–Theoretical Analysis of Heat Transfer, Pressure Drop, and Fouling in Internal Helically Ribbed Tubes of Different Geometries

A numerical analysis of heat transfer and pressure drop for turbulent flow in a series of 15.54-mm inside diameter helically ribbed tubes has been performed. The ranges of geometric parameters were number of rib starts (10 to 40), helix angle (25 to 55 degrees), and rib height (0.3 to 0.6 mm). The effect of grid independence was extensively examined. The computational results match well with the experimental data to validate the accuracy of the numerical model. The effect of each main parameter, rib starts, helix angle, and rib height, on heat transfer and pressure drop is investigated. Considering fouling in practical situations, the ratio of pitch over rib height is an important parameter to select the tubes. It is advisable to select tubes with pitch over rib height ratio greater than 3.5, which have better heat transfer and lower fouling potential.

Frequency and number of resuscitation related rib and sternum fractures are higher than generally considered

Aim of the studyThis study aimed to establish the incidence, number and location of CPR-related skeletal chest injuries (SCI) and to investigate the influence of age, gender, changes in resuscitation guidelines and technique of resuscitation. MethodsWe analysed SCI in 2148 patients who had undergone resuscitation for non-traumatic cardiac arrest, as shown by autopsies performed at the Institute of Forensic Medicine in Ljubljana in the period 2004–2013. ResultsExternal cardiac massage caused SCI in 86% of males and in 91% of females; sternum fractures occurred in 59% of males and 79% of females, rib fractures in 77% of males and 85% of females and sternocostal separations in 33% of males and 12% of females. The average number of all SCI per person was thus almost the same in males and females: 10.95 vs. 10.96. The percentage of patients injured and the number of SCI increased with age. Changes in resuscitation guidelines were also identified as a factor contributing to the incidence and number of SCI. No adverse effect of the use of LUCAS was found. ConclusionIt is generally considered that at least 1/3 of resuscitated patients sustain rib fractures and at least 1/5 sustains sternum fractures. However, our study showed that these injuries are much more frequent and that increased compression rate and depth cause more SCI. Since in the period 2011–2013 accompanying severe injuries occurred in only 1.85% of cases, the resuscitation technique has not yet jeopardised patient's safety, but further close monitoring is needed.

Comparative Anatomical Study on Ferula L. species in NE Iran

In present research, comparative anatomical study was carried on eight Ferula species in NE Iran. The specimens were collected during March- June 2010- 2012. After identification, the cross sections from the base of stem, mature leaves, petioles and mericarps were prepared, and then stained by differential staining. Internal structure of stems, leaves and petioles varied among the species due to the shape and type of collenchymous tissue below the epidermis layer and sclerenchymous strands above the phloem, the shape of vascular bundle, the position and number of secretory ducts and the type of mesophyll. Also, in the mericarps, the number of dorsal rib, vallecular vittae, commissural vittae and wing width changed among the species.

The Value of the Pediatric Skeletal Examination in the Autopsy of Children

The pediatric skeletal examination (PSE) is an autopsy technique recommended for pediatric cases suspicious for nonaccidental injury. The technique requires the reflection of the musculature and periosteum of the ribs, clavicles, long bones, and scapulae, and inspection of the bone surfaces and chondro-osseous interfaces. The technique is time consuming, labor intensive and possibly disfiguring. Therefore, the value of the technique must be measured against the cost. The present study was designed to evaluate the impact of the PSE on the sensitivity of the autopsy. A non-randomized retrospective review of 94 autopsy reports was done. The cause and manner of death for each case was classified as blunt force trauma and homicide. Half of the sample received a PSE during the autopsy and half did not. The number of rib and long bone fractures noted in the reports was significantly greater in the group that received the PSE. The number of cranial, scapular and clavicular fractures was not significantly different between the two groups. The PSE does not increase the visibility of the neurocranium; therefore, a difference in the number of cranial fractures was not expected. Scapular and clavicular fractures were rare in the study population. The insignificant difference between the two groups may be a reflection of the rarity of the fracture as opposed to the sensitivity of the PSE. The results of the study indicate that the PSE increases the sensitivity of the pediatric autopsy with respect to long bone and rib fractures.

PSO 알고리즘을 이용한 다중 하중 스펙트럼 하에서의 항공기 날개 구조부재의 최적 설계 연구

본 논문에서는 항공기 날개의 최적설계 툴을 개발하고, 다중하중스펙트럼 조건에서 항공기 날개의 구조부재에 대한 최적설계를 수행하였다. 공력하중을 계산하기 위해 2차원 CFD의 해석 결과를 사용하였다. 최적화 설계 변수는 리브 및 스파의 개수 및 위치와 두께를 선정하였다. 각각의 비행유형에 대한 순항속도에서의 공력해석 결과로 응력해석을 수행한 후, 피로하중 스펙트럼 임무선도를 활용하여 피로파손해석을 수행하였다. 다중하중 조건의 적용을 위해 손상누적법을 적용하였다. 응력해석에 이은 파손 해석을 포함하는 항공기 날개의 경량화를 진행하였다. 다변수 문제를 효과적으로 최적화하기 위해 PSO(Particle Swarm Optimization) 알고리즘을 사용하였다. In this paper, development of optimal design tools for wing structure is described including multi load spectra condition and fatigue analysis. Two dimensional CFD result are used for calculating aerodynamic force. Design variables are composed of a number of rib and spar, positions, and thickness of each structural member. The mission profile for fatigue analysis is composed based upon the results of CFD analysis, the flight-by-flight spectra method, the excessive curves for gust loads. Minor's rule was used to deal with multi-load condition. Stress analysis and fatigue analysis are performed to calculate objective functions. Particle Swarm Optimization(PSO) algorithm was used to apply to problems which have dozens of design variables.

Patients With Rib Fractures Do Not Develop Delayed Pneumonia: A Prospective, Multicenter Cohort Study of Minor Thoracic Injury

Patients admitted to emergency departments (EDs) for minor thoracic injuries are possibly at risk of delayed pneumonia. We aimed to evaluate the incidence of delayed pneumonia post-minor thoracic injury and the associated risk factors. A prospective, multicenter cohort study was conducted in 4 Canadian EDs, from November 2006 to November 2010. All consecutive patients aged 16 years and older with minor thoracic injury who were discharged from the ED were screened for eligibility. Uniform clinical and radiologic evaluations were performed on the initial ED visit and were repeated at weeks 1 and 2. Relative risk analyses quantified incidence with comparison by age, sex, smoking status, alcohol intoxication, pulmonary comorbidity, ability to cough atelectasis, pain level, and number of rib fractures. Of the 1,057 participants recruited, 347 (32.8%) had at least 1 rib fracture, 87 (8.2%) had asthma, and 36 (3.4%) had chronic obstructive pulmonary disease. Only 6 patients (0.6%; 95% confidence interval 0.24% to 1.17%) developed pneumonia during the follow-up period. The relative risk for patients with preexistent pulmonary disease and radiologically proven rib fractures was 8.6 (P=.045; 95% confidence interval 1.05 to 70.9). Sex, smoking habit, initial atelectasis, ability to cough, and alcohol intoxication were not significantly associated with delayed pneumonia. This prospective cohort study of nonhospitalized patients with minor thoracic injuries revealed a low incidence of delayed pneumonia. Nonetheless, our results support tailored follow-up for asthmatic or chronic obstructive pulmonary disease patients with rib fracture.

Modeling cooling tower fouling in helical-rib tubes based on Von-Karman analogy

This paper provides an analysis on cooling tower fouling data taken in seven 15.54 mm I.D. helically ribbed, copper tubes at R e = 16,000. The geometric parameters include number of rib starts, helix angle, and height. A series of semi-theoretical fouling correlations as a function of the product of area indexes and efficiency indexes are developed. The mass transfer coefficient is calculated by the Von-Karman analogy. The wall shear stress is obtained from the pressure drop. The correlations and the analyses can be used directly to assess the fouling potential of helical-rib in actual cooling water systems.