BACKGROUND Slipping rib syndrome(SRS)is caused by abnormal subluxation of floating ribs,resulting in chronic pain and possible tissue damage.Its prevalence is often overlooked,as it shares symptoms with other musculos...BACKGROUND Slipping rib syndrome(SRS)is caused by abnormal subluxation of floating ribs,resulting in chronic pain and possible tissue damage.Its prevalence is often overlooked,as it shares symptoms with other musculoskeletal conditions,and is more common in young females and athletes.Symptoms include pain along the lower rib margin,aggravated by trunk movements,deep breathing and coughing.Treatment usually starts conservatively with physiotherapy and analgesics.In severe cases,extrapleural rib resection may be required.CASE SUMMARY In April 2023,a 24-year-old woman presented with persistent right hemithorax pain in the eleventh rib for one year.Instrumental examinations,including ultrasonography and magnetic resonance imaging,were negative for abdominal and osteochondral abnormalities.The pain intensity,rated 8/10 on the numeric rating scale(NRS),remained unresponsive to pain therapy.After a careful literature review and discussion with the patient,we opted for a minimally invasive surgical approach.Under general anesthesia,a mini-thoracotomy was performed along the anterior course of the eleventh rib.After exposure,abnormal rib mobility was detected,which led to resection of the medial margin and anchoring to the overlying rib with nonabsorbable sutures.Histological examination revealed no abnormalities.The patient was discharged on the first postoperative day.Pain decreased significantly,reaching 1/10 on the NRS at one month.At 3 months,the patient had mild fluctuating pain(2/10)requiring occasional analgesics but did not interfere with daily activities.CONCLUSION Minimally invasive rib-preserving surgery effectively reduces pain and hospitalization time,offering a valid alternative to conventional rib resection for refractory SRS.展开更多
Background: Reconstruction of Nasal Tip Columella (NTC) subunits is one of the most challenging aspects in functional aesthetic rhinoplasty. Moreover, racial variation for Asian nose rhinoplasty could even demand soph...Background: Reconstruction of Nasal Tip Columella (NTC) subunits is one of the most challenging aspects in functional aesthetic rhinoplasty. Moreover, racial variation for Asian nose rhinoplasty could even demand sophistication of tip and columella strut graft infrastructure enhancement. Various autogenous graft options such as 6th costal cartilage, septal cartilage and conchal cartilage are very commonly considered whilst the 10th costal cartilage is scarcely reported. Objective and Method: The purpose of this manuscript is to illustrate the detailed operative steps to harvest the 10th costal cartilage for infrastructural grafting at NTC subunits by a case illustration. The pros and cons of different cartilage options will be discussed, particularly its application in cleft nose rhinoplasty in Chinese patient. We have adopted the 10th rib as the key option for NTC reconstruction in 11 cases of Chinese cleft secondary rhinoplasty since 2019 and have achieved good and stable results without complications. Conclusion: The 10th costal cartilage is one of the best options in Nasal Tip Columella subunits reconstruction, particularly in complex cleft nose or failure revision aesthetic rhinoplasty cases, due to its safety of harvesting, and the sufficient quality and quantity of grafting materials it provides for simultaneous adjunctive augmentation purpose.展开更多
Rib spalling is a highly severe issue during mining in deep-buried large-mining-height working faces.This study takes Zhaogu No.2 Coal Mine in Jiaozuo Coalfield,China,as the research background and carries out three f...Rib spalling is a highly severe issue during mining in deep-buried large-mining-height working faces.This study takes Zhaogu No.2 Coal Mine in Jiaozuo Coalfield,China,as the research background and carries out three focused works to address this problem.Firstly,field measurements were conducted to clarify rib spalling characteristics:the coal wall is dominated by shear failure,internal cracks are mainly distributed 3–6 m above the coal wall surface,and the maximum depth of crack development reaches 3 m.Secondly,Universal Distinct Element Code(UDEC)numerical simulation software was used to build a rib spalling model,with the Trigon model adopted to divide the coal wall into blocks.Analysis of four key factors shows that increased buried depth and mining height significantly raise the total length of coal wall internal cracks,increasing rib spalling risk,while higher coal body strength and support strength effectively alleviate this phenomenon.Finally,an orthogonal experiment was designed to quantitatively determine the influence degree of the four factors on rib spalling.Results show that coal body strength has the greatest impact,followed by support strength,mining height,and mining depth in order of influence.This study provides valuable theoretical guidance for on-site prevention and control of coal wall rib spalling.展开更多
Objective:To compare the diagnostic value of 99mTc-MDP SPECT/CT and MSCT in detecting thoracic wall and rib involvement in lung adenocarcinoma.Methods:A retrospective analysis was conducted on the imaging data of 78 t...Objective:To compare the diagnostic value of 99mTc-MDP SPECT/CT and MSCT in detecting thoracic wall and rib involvement in lung adenocarcinoma.Methods:A retrospective analysis was conducted on the imaging data of 78 thoracic wall and rib lesions from 66 patients,a total of 32 males and 34 females,aged(53.2±5.6)years old with pathologically confirmed lung adenocarcinoma who underwent both 99mTc-MDP SPECT/CT and MSCT examinations from March 2017 to September 2023.The diagnostic efficacy of the two imaging modalities was compared using pathological confirmation or clinical follow-up as the gold standard.Results:Pathological confirmation or clinical follow-up revealed 74 lesions with thoracic wall bone involvement in lung adenocarcinoma(20 lesions confirmed by surgical pathology and 54 lesions confirmed by clinical follow-up)and 4 lesions without thoracic wall or rib involvement(2 lesions confirmed by surgical pathology and 2 lesions confirmed by clinical follow-up).The diagnostic sensitivity,specificity,and accuracy of 99mTc-MDP SPECT/CT were 97.3%,50.0%,and 94.9%,respectively.Its diagnostic sensitivity and accuracy were higher than those of MSCT(72.3%and 74.4%,respectively),with statistically significant differences(P<0.05).The specificity of 99mTc-MDP SPECT/CT was lower than that of MSCT(100.0%),but the difference was not statistically significant(P<0.05).There were no statistically significant differences in the positive predictive value and negative predictive value between 99mTc-MDP SPECT/CT and MSCT(P>0.05).99mTc-MDP SPECT/CT examination revised the MSCT tumor staging in 14 patients[21.2%(14/66)]with lung adenocarcinoma.Conclusion:99mTc-MDP SPECT/CT imaging demonstrates superior diagnostic efficacy compared to MSCT in detecting thoracic wall and rib involvement in lung adenocarcinoma.It offers more accurate tumor staging than MSCT,and an accurate diagnosis aids in clinical treatment decision-making.展开更多
The mass transport and ohmic losses in proton exchange membrane fuel cells(PEMFCs)is significantly influenced by the channel to rib width ratio(CRWR),particularly when accounting for the interfacial contact resistance...The mass transport and ohmic losses in proton exchange membrane fuel cells(PEMFCs)is significantly influenced by the channel to rib width ratio(CRWR),particularly when accounting for the interfacial contact resistance between bipolar plates(BPs)and gas diffusion layers(GDLs)(ICRBP-GDL).Both the determination of the optimal CRWR value and the development of an efficient flow field structure are significantly influenced by ICRBP-GDLs.To investigate this,three-dimensional numerical models were developed,revealing that selecting an optimal CRWR tailored to specific ICRBP-GDL values can effectively balance mass transport and ohmic losses.Building on this insight,a novel island two-dimensional flow field design is proposed,demonstrating the ability to enhance oxygen transport to the catalyst layer(CL)and achieve a more uniform oxygen distribution without increasing ohmic losses.Compared to conventional straight and serpentine flow fields,the island flow field improves output power density by 4.5%and 3.5%,respectively,while reducing the liquid water coverage ratio by 30%.Additionally,the study identifies optimal CRWR values for conventional flow fields corresponding to ICRBP-GDLs of 2.5,5,10,20,and 40 mΩ·cm^(2) as 1.5,1.5,1.0,0.67,and 0.43,respectively.For the island flow field,the optimal CRWRs are consistently smaller-1.5,1.0,0.67,0.43,and 0.43-due to its superior mass transfer capability.This work provides a valuable framework for optimizing flow field designs to achieve improved PEMFC performance.展开更多
In order to improve rib stability,failure criteria and instability mode of a thick coal seam with inter-band rock layer are analysed in this study.A three-dimensional mechanical model is established for the rib by con...In order to improve rib stability,failure criteria and instability mode of a thick coal seam with inter-band rock layer are analysed in this study.A three-dimensional mechanical model is established for the rib by considering the rock layer.A safety factor is defined foy the rib,and it is observed that the safety factor exhibits a positive correlation with the thickness and strength of the inter-band rock.A calculation method for determining critical parameters of the rock layer is presented to ensure the rib stability.It is revealed that incomplete propagation of the fracture at the hard rock constitutes a fundamental prerequisite for ensuring the rib stability.The influence of the position of the inter-band rock in the coal seam on failure mechanism of the rib was thoroughly investigated by developing a series of physical models for the rib at the face area.The best position for the inter-band rock in the coal seam is at a height of 1.5 m away from the roof line,which tends to provide a good stability state for the rib.For different inter-band rock positions,two ways of controlling rib by increasing supports stiffness and flexible grouting reinforcement are proposed.展开更多
Non-pillar mining technology with automatically formed roadway is a new mining method without coal pillar reservation and roadway excavation.The stability control of automatically formed roadway is the key to the succ...Non-pillar mining technology with automatically formed roadway is a new mining method without coal pillar reservation and roadway excavation.The stability control of automatically formed roadway is the key to the successful application of the new method.In order to realize the stability control of the roadway surrounding rock,the mechanical model of the roof and rib support structure is established,and the influence mechanism of the automatically formed roadway parameters on the compound force is revealed.On this basis,the roof and rib support structure technology of confined lightweight concrete is proposed,and its mechanical tests under different eccentricity are carried out.The results show that the bearing capacity of confined lightweight concrete specimens is basically the same as that of ordinary confined concrete specimens.The bearing capacity of confined lightweight concrete specimens under different eccentricities is 1.95 times higher than those of U-shaped steel specimens.By comparing the test results with the theoretical calculated results of the confined concrete,the calculation method of the bearing capacity for the confined lightweight concrete structure is selected.The design method of confined lightweight concrete support structure is established,and is successfully applied in the extra-large mine,Ningtiaota Coal Mine,China.展开更多
This study deals with base pressure management in a duct for various values of the Mach number(M),namely,Mach number corresponding to sonic and four supersonic conditions.In addition to the Mach number,the nozzle pres...This study deals with base pressure management in a duct for various values of the Mach number(M),namely,Mach number corresponding to sonic and four supersonic conditions.In addition to the Mach number,the nozzle pressure ratio(NPR),the area ratio,the rib dimension,and the duct length are influential parameters.The following specific values are examined at M=1,1.36,1.64,and 2,and NPRs between 1.5 and 10.The base pressure is determined by positioning ribs of varying heights at predetermined intervals throughout the length of the square duct.When the level of expansion is varied,it is seen that the base pressure initially drops for overexpanded flows and increases for under-expanded flows.When ribs are present,the flow field in the duct and pressure inside the duct fluctuate as the base pressure rises.Under-expanded flows can achieve a base pressure value that is suitably high without experiencing excessive changes in the duct flow in terms of static pressure if a rib height around 10%of the duct height close to the nozzle exit is considered.Rectangular rib passive control does not negatively affect the duct’s flow field.展开更多
Hot flow forming(HFF)is a promising forming technology to manufacture thin-walled cylindrical part with longitudinal inner ribs(CPLIRs)made of magnesium(Mg)alloys,which has wide applications in the aerospace field.How...Hot flow forming(HFF)is a promising forming technology to manufacture thin-walled cylindrical part with longitudinal inner ribs(CPLIRs)made of magnesium(Mg)alloys,which has wide applications in the aerospace field.However,due to the thermo-mechanical coupling effect and the existence of stiffened structure,complex microstructure evolution and uneven microstructure occur easily at the cylindrical wall(CW)and inner rib(IR)of Mg alloy thin-walled CPLIRs during the HFF.In this paper,a modified cellular automaton(CA)model of Mg alloy considering the effects of deformation conditions on material parameters was developed using the artificial neural network(ANN)method.It is found that the ANN-modified CA model exhibits better predictability for the microstructure of hot deformation than the conventional CA model.Furthermore,the microstructure evolution of ZK61 alloy CPLIRs during the HFF was analyzed by coupling the modified CA model and finite element analysis(FEA).The results show that compared with the microstructure at the same layer of the IR,more refined grains and less sufficient DRX resulted from larger strain and strain rate occur at that of the CW;various differences of strain and strain rate in the wall-thickness exist between the CW and IR,which leads to the inhomogeneity of microstructure rising firstly and declining from the inside layer to outside layer;the obtained Hall-Petch relationship between the measured microhardness and predicted grain sizes at the CW and the IR indicates the reliability of the coupled FEA-CA simulation results.展开更多
Background:Autologous costal grafts are used universally in clinical practice for rhinoplasty and reconstruction.However,surgeons worldwide have not agreed on the details of graft harvesting,including rib selection,si...Background:Autologous costal grafts are used universally in clinical practice for rhinoplasty and reconstruction.However,surgeons worldwide have not agreed on the details of graft harvesting,including rib selection,side preference,operation mode,cutting methods,and handling of the periosteum and perichondrium.This study aimed to provide an overview of the novel techniques used for auto-rib harvesting in rhinoplasty within the past 5 years and identify potential avenues for future research.Methods:We searched for related articles in PubMed,Embase,and Web of Science from 2019 to 2023,summa-rized crucial but controversial steps in recent practice,and analyzed their theoretical basis and clinical feasibility.Results:Auto-rib and cartilage open harvest is still mainstream in rhinoplasty and reconstruction,with the 5th to 8th ribs and cartilage being the most used.The laparoscopic harvest is gaining attention,being second only to the open harvest,with the 9th/10th ribs and cartilages being particularly convenient.The clinical applications of full-cut and split-cut methods differ in their advantages.Except for some special reasons,almost all studies tended to preserve the periosteum and perichondrium in situ,and few surgeons chose to harvest the grafts on the left side.Conclusion:Multiple techniques have emerged,requiring surgeons to balance the benefits and risks of various strategies at each step.New theories and techniques should be fully tested promptly and in clinical practice before wide application.Overall,a professional consensus is needed for better directivity,precision,and stability in clinical practice.展开更多
In order to study the residual stress distribution law of welded joints of arch ribs of large-span steel pipe concrete arch bridges,numerical simulation of temperature,stress and strain fields based on ABAQUS for weld...In order to study the residual stress distribution law of welded joints of arch ribs of large-span steel pipe concrete arch bridges,numerical simulation of temperature,stress and strain fields based on ABAQUS for welded joints of arch-ribbed steel tubes using 7-,8-and 9-layer welds is carried out and its accuracy is demonstrated.The steel pipe welding temperature changes,residual stress distribution,different processes residual stress changes in the law,the prediction of post-weld residual stress distribution and deformation are studied in this paper.The results show that the temperature field values and test results are more consistent with the accuracy of numerical simulation of welding,the welding process is mainly in the form of heat transfer;Residual high stresses are predominantly distributed in the Fusion zone(FZ)and Heat-affected zone(HAZ),with residual stress levels tending to decrease from the center of the weld along the axial path,the maximum stress appears in the FZ and HAZ junction;The number of welding layers has an effect on the residual stress distribution,the number of welding layers increases,the residual stress tends to decrease,while the FZ and HAZ high stress area range shrinks;Increasing the number of plies will increase the amount of residual distortion.展开更多
Thoraco-brachial outlet syndrome (TDSD) or cervical rib brings together all the clinical symptoms (arterial, neurological and/or venous) due to extrinsic, intermittent or permanent compression of the vascular-nervous ...Thoraco-brachial outlet syndrome (TDSD) or cervical rib brings together all the clinical symptoms (arterial, neurological and/or venous) due to extrinsic, intermittent or permanent compression of the vascular-nervous elements of the root of the upper limb during cervico-thoraco-brachial crossing syndrome. This pathology is relatively common but often overlooked;it affects women more often (between 4/1 and 2/1) and is rare in children. We report the case of a 59-year-old female patient seen in the department for paresthesia and muscular weakness of the upper limbs rated 3/5 on the right and 4/5 on the left progressively evolving over 39 years, electromyography (EMG) showed indicated compression of the brachial plexus and the CT scan confirmed the presence of bilateral cervical ribs fused with the first on the left. She benefited from physiotherapy while awaiting her surgery, and unfortunately, she died of a stroke in the traumatology department. This pathology is the first in our department to be supported by a review of the literature.展开更多
Researchers from the National Institute for Occupational Safety and Health(NIOSH)are developing a coal pillar rib rating(CPRR)technique to measure the integrity of coal ribs.The CPRR characterizes the rib composition ...Researchers from the National Institute for Occupational Safety and Health(NIOSH)are developing a coal pillar rib rating(CPRR)technique to measure the integrity of coal ribs.The CPRR characterizes the rib composition and evaluates its impact on the inherent stability of the coal ribs.The CPRR utilizes four parameters:rib homogeneity,bedding condition,face cleat orientation with respect to entry direction,and rib height.All these parameters are measurable in the field.A rib data collecting procedure and a simple sheet to calculate the CPRR were developed.The developed CPRR can be used as a rib quality mapping tool in underground coal mines and to determine the potential of local rib instabilities and support requirements associated with overburden depth.CPRR calculations were conducted for 22 surveyed solid coal ribs,mainly composed of coal units.Based on this study,the rib performance was classified into four categories.A preliminary minimum primary rib support density(PRSD)line was obtained from these surveyed cases.Two sample cases are presented that illustrate the data collection form and CPRR calculations.展开更多
The National Institute for Occupational Safety and Health(NIOSH)conducted a comprehensive monitoring program in a room-and-pillar mine located in Southern Virginia.The deformation and the stress change in an instrumen...The National Institute for Occupational Safety and Health(NIOSH)conducted a comprehensive monitoring program in a room-and-pillar mine located in Southern Virginia.The deformation and the stress change in an instrumented pillar were monitored during the progress of pillar retreat mining at two sites of different geological conditions and depths of cover.The main objectives of the monitoring program were to better understand the stress transfer and load shedding on coal pillars and to quantify the rib deformation due to pillar retreat mining;and to examine the effect of rib geology and overburden depth on coal rib performance.The instrumentation at both sites included pull-out tests to measure the anchorage capacity of rib bolts,load cells mounted on rib bolts to monitor the induced loads in the bolts,borehole pressure cells(BPCs)installed at various depths in the study pillar to measure the change in vertical pressure within the pillar,and roof and rib extensometers installed to quantify the vertical displacement of the roof and the horizontal displacement of the rib that would occur during the retreat mining process.The outcome from the monitoring program provides insight into coal pillar rib support optimization at various depths and geological conditions.Also,this study contributes to the NIOSH rib support database in U.S coal mines and provides essential data for rib support design.展开更多
Background: Costal fracture surgical is still a debate, therefore we shall select between early and delay surgical management. Case Report: We are reporting two cases of post road traffic clash delay ribs fractures os...Background: Costal fracture surgical is still a debate, therefore we shall select between early and delay surgical management. Case Report: We are reporting two cases of post road traffic clash delay ribs fractures osteosynthesis involving a 63-year-old man with multistage fractures on the left and pulmonary pinning of one of the costal arches, complicated by a homolateral haemothorax and a 41-year-old man with a bilateral flail chest. Conclusion: The simple postoperative course and the immediate postoperative improvement in the patient’s clinical respiratory condition enabled us to discuss the time frame for management, in this case the indication for early or later surgery.展开更多
Objective: To explore the application value of disposable grooved negative pressure drainage tubes in rib fracture incision and internal fixation. Methods: Seventy-five patients admitted to our Department of Trauma Su...Objective: To explore the application value of disposable grooved negative pressure drainage tubes in rib fracture incision and internal fixation. Methods: Seventy-five patients admitted to our Department of Trauma Surgery from June 2022 to April 2024 who underwent rib fracture osteotomy and internal fixation were selected. According to the types of drainage tubes left in the patients after the operation, they were divided into the observation group (35 cases who were left with disposable grooved negative pressure drainage tubes) and the control group (40 cases who were left with closed silicone thoracic drainage tubes). Comparison of chest drainage, pain, postoperative complications, secondary chest penetration rate, drain placement time, hospitalization time, and treatment costs were compared between the two groups. Results: The total postoperative chest drainage volume of the observation group was less than that of the control group (P < 0.05);the degree of pain, the incidence of postoperative complications, and the rate of secondary chest puncture in the observation group were lower than that of the control group three days after the operation (P < 0.05);and the time of drain placement in the observation group was shorter than that of the control group (P < 0.05). Conclusion: The application of disposable grooved negative pressure drainage tubes in rib fracture incision and internal fixation can significantly improve patients’ postoperative pain and discomfort, reduce complications, lower the rate of secondary chest penetration, promote patients’ postoperative recovery, decrease the amount of postoperative chest drainage, and shorten the time of drain placement, which is worthy of clinical promotion and application.展开更多
Ensuring rib stability during pillar extraction is of prime importance in bord and pillar(B&P) method of underground coal mining with caving. Rib stability has been assessed here by way of assessing factor of safe...Ensuring rib stability during pillar extraction is of prime importance in bord and pillar(B&P) method of underground coal mining with caving. Rib stability has been assessed here by way of assessing factor of safety(FOS), a ratio of the strength of rib to stress on it. Earlier formulations for rib stability when applied to case studies gave very low FOS value suggesting significant ground control problems, which were contrary to the field observations. This has necessitated the need to revisit the concept of rib stability. The stress coming on the rib is estimated with the use of numerical modeling technique using the FLAC^(3D) software. The methodology of assessing rib-stability with the help of suggested rib-strength formulation has been validated at eight Indian coal mines. The outcome of this study finds relevance and importance in ensuring underground coal liquidation with improved safety and conservation.展开更多
文摘BACKGROUND Slipping rib syndrome(SRS)is caused by abnormal subluxation of floating ribs,resulting in chronic pain and possible tissue damage.Its prevalence is often overlooked,as it shares symptoms with other musculoskeletal conditions,and is more common in young females and athletes.Symptoms include pain along the lower rib margin,aggravated by trunk movements,deep breathing and coughing.Treatment usually starts conservatively with physiotherapy and analgesics.In severe cases,extrapleural rib resection may be required.CASE SUMMARY In April 2023,a 24-year-old woman presented with persistent right hemithorax pain in the eleventh rib for one year.Instrumental examinations,including ultrasonography and magnetic resonance imaging,were negative for abdominal and osteochondral abnormalities.The pain intensity,rated 8/10 on the numeric rating scale(NRS),remained unresponsive to pain therapy.After a careful literature review and discussion with the patient,we opted for a minimally invasive surgical approach.Under general anesthesia,a mini-thoracotomy was performed along the anterior course of the eleventh rib.After exposure,abnormal rib mobility was detected,which led to resection of the medial margin and anchoring to the overlying rib with nonabsorbable sutures.Histological examination revealed no abnormalities.The patient was discharged on the first postoperative day.Pain decreased significantly,reaching 1/10 on the NRS at one month.At 3 months,the patient had mild fluctuating pain(2/10)requiring occasional analgesics but did not interfere with daily activities.CONCLUSION Minimally invasive rib-preserving surgery effectively reduces pain and hospitalization time,offering a valid alternative to conventional rib resection for refractory SRS.
文摘Background: Reconstruction of Nasal Tip Columella (NTC) subunits is one of the most challenging aspects in functional aesthetic rhinoplasty. Moreover, racial variation for Asian nose rhinoplasty could even demand sophistication of tip and columella strut graft infrastructure enhancement. Various autogenous graft options such as 6th costal cartilage, septal cartilage and conchal cartilage are very commonly considered whilst the 10th costal cartilage is scarcely reported. Objective and Method: The purpose of this manuscript is to illustrate the detailed operative steps to harvest the 10th costal cartilage for infrastructural grafting at NTC subunits by a case illustration. The pros and cons of different cartilage options will be discussed, particularly its application in cleft nose rhinoplasty in Chinese patient. We have adopted the 10th rib as the key option for NTC reconstruction in 11 cases of Chinese cleft secondary rhinoplasty since 2019 and have achieved good and stable results without complications. Conclusion: The 10th costal cartilage is one of the best options in Nasal Tip Columella subunits reconstruction, particularly in complex cleft nose or failure revision aesthetic rhinoplasty cases, due to its safety of harvesting, and the sufficient quality and quantity of grafting materials it provides for simultaneous adjunctive augmentation purpose.
基金supported by the National Key Research and Development Program of China(No.2023YFC2907501)the National Natural Science Foundation of China(No.52374106)+1 种基金the China Postdoctoral Science Foundation(Grant no.2024T171006)the National Natural Science Foundation of China(Grant no.52204163).
文摘Rib spalling is a highly severe issue during mining in deep-buried large-mining-height working faces.This study takes Zhaogu No.2 Coal Mine in Jiaozuo Coalfield,China,as the research background and carries out three focused works to address this problem.Firstly,field measurements were conducted to clarify rib spalling characteristics:the coal wall is dominated by shear failure,internal cracks are mainly distributed 3–6 m above the coal wall surface,and the maximum depth of crack development reaches 3 m.Secondly,Universal Distinct Element Code(UDEC)numerical simulation software was used to build a rib spalling model,with the Trigon model adopted to divide the coal wall into blocks.Analysis of four key factors shows that increased buried depth and mining height significantly raise the total length of coal wall internal cracks,increasing rib spalling risk,while higher coal body strength and support strength effectively alleviate this phenomenon.Finally,an orthogonal experiment was designed to quantitatively determine the influence degree of the four factors on rib spalling.Results show that coal body strength has the greatest impact,followed by support strength,mining height,and mining depth in order of influence.This study provides valuable theoretical guidance for on-site prevention and control of coal wall rib spalling.
文摘Objective:To compare the diagnostic value of 99mTc-MDP SPECT/CT and MSCT in detecting thoracic wall and rib involvement in lung adenocarcinoma.Methods:A retrospective analysis was conducted on the imaging data of 78 thoracic wall and rib lesions from 66 patients,a total of 32 males and 34 females,aged(53.2±5.6)years old with pathologically confirmed lung adenocarcinoma who underwent both 99mTc-MDP SPECT/CT and MSCT examinations from March 2017 to September 2023.The diagnostic efficacy of the two imaging modalities was compared using pathological confirmation or clinical follow-up as the gold standard.Results:Pathological confirmation or clinical follow-up revealed 74 lesions with thoracic wall bone involvement in lung adenocarcinoma(20 lesions confirmed by surgical pathology and 54 lesions confirmed by clinical follow-up)and 4 lesions without thoracic wall or rib involvement(2 lesions confirmed by surgical pathology and 2 lesions confirmed by clinical follow-up).The diagnostic sensitivity,specificity,and accuracy of 99mTc-MDP SPECT/CT were 97.3%,50.0%,and 94.9%,respectively.Its diagnostic sensitivity and accuracy were higher than those of MSCT(72.3%and 74.4%,respectively),with statistically significant differences(P<0.05).The specificity of 99mTc-MDP SPECT/CT was lower than that of MSCT(100.0%),but the difference was not statistically significant(P<0.05).There were no statistically significant differences in the positive predictive value and negative predictive value between 99mTc-MDP SPECT/CT and MSCT(P>0.05).99mTc-MDP SPECT/CT examination revised the MSCT tumor staging in 14 patients[21.2%(14/66)]with lung adenocarcinoma.Conclusion:99mTc-MDP SPECT/CT imaging demonstrates superior diagnostic efficacy compared to MSCT in detecting thoracic wall and rib involvement in lung adenocarcinoma.It offers more accurate tumor staging than MSCT,and an accurate diagnosis aids in clinical treatment decision-making.
基金the financial support of Natural Science Foundation of Hunan Province(2023JJ40261).
文摘The mass transport and ohmic losses in proton exchange membrane fuel cells(PEMFCs)is significantly influenced by the channel to rib width ratio(CRWR),particularly when accounting for the interfacial contact resistance between bipolar plates(BPs)and gas diffusion layers(GDLs)(ICRBP-GDL).Both the determination of the optimal CRWR value and the development of an efficient flow field structure are significantly influenced by ICRBP-GDLs.To investigate this,three-dimensional numerical models were developed,revealing that selecting an optimal CRWR tailored to specific ICRBP-GDL values can effectively balance mass transport and ohmic losses.Building on this insight,a novel island two-dimensional flow field design is proposed,demonstrating the ability to enhance oxygen transport to the catalyst layer(CL)and achieve a more uniform oxygen distribution without increasing ohmic losses.Compared to conventional straight and serpentine flow fields,the island flow field improves output power density by 4.5%and 3.5%,respectively,while reducing the liquid water coverage ratio by 30%.Additionally,the study identifies optimal CRWR values for conventional flow fields corresponding to ICRBP-GDLs of 2.5,5,10,20,and 40 mΩ·cm^(2) as 1.5,1.5,1.0,0.67,and 0.43,respectively.For the island flow field,the optimal CRWRs are consistently smaller-1.5,1.0,0.67,0.43,and 0.43-due to its superior mass transfer capability.This work provides a valuable framework for optimizing flow field designs to achieve improved PEMFC performance.
基金financial support from the National Key Research and Development Program of China (No.2023YFC2907501)the National Natural Science Foundation of China (No.52374106)the Fundamental Research Funds for the Central Universities (No.2023ZKPYNY01)。
文摘In order to improve rib stability,failure criteria and instability mode of a thick coal seam with inter-band rock layer are analysed in this study.A three-dimensional mechanical model is established for the rib by considering the rock layer.A safety factor is defined foy the rib,and it is observed that the safety factor exhibits a positive correlation with the thickness and strength of the inter-band rock.A calculation method for determining critical parameters of the rock layer is presented to ensure the rib stability.It is revealed that incomplete propagation of the fracture at the hard rock constitutes a fundamental prerequisite for ensuring the rib stability.The influence of the position of the inter-band rock in the coal seam on failure mechanism of the rib was thoroughly investigated by developing a series of physical models for the rib at the face area.The best position for the inter-band rock in the coal seam is at a height of 1.5 m away from the roof line,which tends to provide a good stability state for the rib.For different inter-band rock positions,two ways of controlling rib by increasing supports stiffness and flexible grouting reinforcement are proposed.
基金Project(2023YFC2907600)supported by the National Key Research and Development Program of ChinaProjects(42077267,42277174,52074164)supported by the National Natural Science Foundation of ChinaProject(2024JCCXSB01)supported by the Fundamental Research Funds for the Central Universities,China。
文摘Non-pillar mining technology with automatically formed roadway is a new mining method without coal pillar reservation and roadway excavation.The stability control of automatically formed roadway is the key to the successful application of the new method.In order to realize the stability control of the roadway surrounding rock,the mechanical model of the roof and rib support structure is established,and the influence mechanism of the automatically formed roadway parameters on the compound force is revealed.On this basis,the roof and rib support structure technology of confined lightweight concrete is proposed,and its mechanical tests under different eccentricity are carried out.The results show that the bearing capacity of confined lightweight concrete specimens is basically the same as that of ordinary confined concrete specimens.The bearing capacity of confined lightweight concrete specimens under different eccentricities is 1.95 times higher than those of U-shaped steel specimens.By comparing the test results with the theoretical calculated results of the confined concrete,the calculation method of the bearing capacity for the confined lightweight concrete structure is selected.The design method of confined lightweight concrete support structure is established,and is successfully applied in the extra-large mine,Ningtiaota Coal Mine,China.
文摘This study deals with base pressure management in a duct for various values of the Mach number(M),namely,Mach number corresponding to sonic and four supersonic conditions.In addition to the Mach number,the nozzle pressure ratio(NPR),the area ratio,the rib dimension,and the duct length are influential parameters.The following specific values are examined at M=1,1.36,1.64,and 2,and NPRs between 1.5 and 10.The base pressure is determined by positioning ribs of varying heights at predetermined intervals throughout the length of the square duct.When the level of expansion is varied,it is seen that the base pressure initially drops for overexpanded flows and increases for under-expanded flows.When ribs are present,the flow field in the duct and pressure inside the duct fluctuate as the base pressure rises.Under-expanded flows can achieve a base pressure value that is suitably high without experiencing excessive changes in the duct flow in terms of static pressure if a rib height around 10%of the duct height close to the nozzle exit is considered.Rectangular rib passive control does not negatively affect the duct’s flow field.
基金supported by the National Nat-ural Science Foundation of China(Grant Nos.51775194 and 52090043).
文摘Hot flow forming(HFF)is a promising forming technology to manufacture thin-walled cylindrical part with longitudinal inner ribs(CPLIRs)made of magnesium(Mg)alloys,which has wide applications in the aerospace field.However,due to the thermo-mechanical coupling effect and the existence of stiffened structure,complex microstructure evolution and uneven microstructure occur easily at the cylindrical wall(CW)and inner rib(IR)of Mg alloy thin-walled CPLIRs during the HFF.In this paper,a modified cellular automaton(CA)model of Mg alloy considering the effects of deformation conditions on material parameters was developed using the artificial neural network(ANN)method.It is found that the ANN-modified CA model exhibits better predictability for the microstructure of hot deformation than the conventional CA model.Furthermore,the microstructure evolution of ZK61 alloy CPLIRs during the HFF was analyzed by coupling the modified CA model and finite element analysis(FEA).The results show that compared with the microstructure at the same layer of the IR,more refined grains and less sufficient DRX resulted from larger strain and strain rate occur at that of the CW;various differences of strain and strain rate in the wall-thickness exist between the CW and IR,which leads to the inhomogeneity of microstructure rising firstly and declining from the inside layer to outside layer;the obtained Hall-Petch relationship between the measured microhardness and predicted grain sizes at the CW and the IR indicates the reliability of the coupled FEA-CA simulation results.
文摘Background:Autologous costal grafts are used universally in clinical practice for rhinoplasty and reconstruction.However,surgeons worldwide have not agreed on the details of graft harvesting,including rib selection,side preference,operation mode,cutting methods,and handling of the periosteum and perichondrium.This study aimed to provide an overview of the novel techniques used for auto-rib harvesting in rhinoplasty within the past 5 years and identify potential avenues for future research.Methods:We searched for related articles in PubMed,Embase,and Web of Science from 2019 to 2023,summa-rized crucial but controversial steps in recent practice,and analyzed their theoretical basis and clinical feasibility.Results:Auto-rib and cartilage open harvest is still mainstream in rhinoplasty and reconstruction,with the 5th to 8th ribs and cartilage being the most used.The laparoscopic harvest is gaining attention,being second only to the open harvest,with the 9th/10th ribs and cartilages being particularly convenient.The clinical applications of full-cut and split-cut methods differ in their advantages.Except for some special reasons,almost all studies tended to preserve the periosteum and perichondrium in situ,and few surgeons chose to harvest the grafts on the left side.Conclusion:Multiple techniques have emerged,requiring surgeons to balance the benefits and risks of various strategies at each step.New theories and techniques should be fully tested promptly and in clinical practice before wide application.Overall,a professional consensus is needed for better directivity,precision,and stability in clinical practice.
基金Sponsored by the National Natural Science Foundation of China(Grant No.52268048)the Guangxi Key Technology Research and Development Program(Grant No.GUI-KEAB23026101)the Guangxi Science and Technology Major Special Project(Grant No.GUI-KEAA22068066).
文摘In order to study the residual stress distribution law of welded joints of arch ribs of large-span steel pipe concrete arch bridges,numerical simulation of temperature,stress and strain fields based on ABAQUS for welded joints of arch-ribbed steel tubes using 7-,8-and 9-layer welds is carried out and its accuracy is demonstrated.The steel pipe welding temperature changes,residual stress distribution,different processes residual stress changes in the law,the prediction of post-weld residual stress distribution and deformation are studied in this paper.The results show that the temperature field values and test results are more consistent with the accuracy of numerical simulation of welding,the welding process is mainly in the form of heat transfer;Residual high stresses are predominantly distributed in the Fusion zone(FZ)and Heat-affected zone(HAZ),with residual stress levels tending to decrease from the center of the weld along the axial path,the maximum stress appears in the FZ and HAZ junction;The number of welding layers has an effect on the residual stress distribution,the number of welding layers increases,the residual stress tends to decrease,while the FZ and HAZ high stress area range shrinks;Increasing the number of plies will increase the amount of residual distortion.
文摘Thoraco-brachial outlet syndrome (TDSD) or cervical rib brings together all the clinical symptoms (arterial, neurological and/or venous) due to extrinsic, intermittent or permanent compression of the vascular-nervous elements of the root of the upper limb during cervico-thoraco-brachial crossing syndrome. This pathology is relatively common but often overlooked;it affects women more often (between 4/1 and 2/1) and is rare in children. We report the case of a 59-year-old female patient seen in the department for paresthesia and muscular weakness of the upper limbs rated 3/5 on the right and 4/5 on the left progressively evolving over 39 years, electromyography (EMG) showed indicated compression of the brachial plexus and the CT scan confirmed the presence of bilateral cervical ribs fused with the first on the left. She benefited from physiotherapy while awaiting her surgery, and unfortunately, she died of a stroke in the traumatology department. This pathology is the first in our department to be supported by a review of the literature.
文摘Researchers from the National Institute for Occupational Safety and Health(NIOSH)are developing a coal pillar rib rating(CPRR)technique to measure the integrity of coal ribs.The CPRR characterizes the rib composition and evaluates its impact on the inherent stability of the coal ribs.The CPRR utilizes four parameters:rib homogeneity,bedding condition,face cleat orientation with respect to entry direction,and rib height.All these parameters are measurable in the field.A rib data collecting procedure and a simple sheet to calculate the CPRR were developed.The developed CPRR can be used as a rib quality mapping tool in underground coal mines and to determine the potential of local rib instabilities and support requirements associated with overburden depth.CPRR calculations were conducted for 22 surveyed solid coal ribs,mainly composed of coal units.Based on this study,the rib performance was classified into four categories.A preliminary minimum primary rib support density(PRSD)line was obtained from these surveyed cases.Two sample cases are presented that illustrate the data collection form and CPRR calculations.
基金The authors want to thank Todd Minoski for preparing the data collection system and James Addis and Cynthia Hollerich for help with installing the test instruments.
文摘The National Institute for Occupational Safety and Health(NIOSH)conducted a comprehensive monitoring program in a room-and-pillar mine located in Southern Virginia.The deformation and the stress change in an instrumented pillar were monitored during the progress of pillar retreat mining at two sites of different geological conditions and depths of cover.The main objectives of the monitoring program were to better understand the stress transfer and load shedding on coal pillars and to quantify the rib deformation due to pillar retreat mining;and to examine the effect of rib geology and overburden depth on coal rib performance.The instrumentation at both sites included pull-out tests to measure the anchorage capacity of rib bolts,load cells mounted on rib bolts to monitor the induced loads in the bolts,borehole pressure cells(BPCs)installed at various depths in the study pillar to measure the change in vertical pressure within the pillar,and roof and rib extensometers installed to quantify the vertical displacement of the roof and the horizontal displacement of the rib that would occur during the retreat mining process.The outcome from the monitoring program provides insight into coal pillar rib support optimization at various depths and geological conditions.Also,this study contributes to the NIOSH rib support database in U.S coal mines and provides essential data for rib support design.
文摘Background: Costal fracture surgical is still a debate, therefore we shall select between early and delay surgical management. Case Report: We are reporting two cases of post road traffic clash delay ribs fractures osteosynthesis involving a 63-year-old man with multistage fractures on the left and pulmonary pinning of one of the costal arches, complicated by a homolateral haemothorax and a 41-year-old man with a bilateral flail chest. Conclusion: The simple postoperative course and the immediate postoperative improvement in the patient’s clinical respiratory condition enabled us to discuss the time frame for management, in this case the indication for early or later surgery.
文摘Objective: To explore the application value of disposable grooved negative pressure drainage tubes in rib fracture incision and internal fixation. Methods: Seventy-five patients admitted to our Department of Trauma Surgery from June 2022 to April 2024 who underwent rib fracture osteotomy and internal fixation were selected. According to the types of drainage tubes left in the patients after the operation, they were divided into the observation group (35 cases who were left with disposable grooved negative pressure drainage tubes) and the control group (40 cases who were left with closed silicone thoracic drainage tubes). Comparison of chest drainage, pain, postoperative complications, secondary chest penetration rate, drain placement time, hospitalization time, and treatment costs were compared between the two groups. Results: The total postoperative chest drainage volume of the observation group was less than that of the control group (P < 0.05);the degree of pain, the incidence of postoperative complications, and the rate of secondary chest puncture in the observation group were lower than that of the control group three days after the operation (P < 0.05);and the time of drain placement in the observation group was shorter than that of the control group (P < 0.05). Conclusion: The application of disposable grooved negative pressure drainage tubes in rib fracture incision and internal fixation can significantly improve patients’ postoperative pain and discomfort, reduce complications, lower the rate of secondary chest penetration, promote patients’ postoperative recovery, decrease the amount of postoperative chest drainage, and shorten the time of drain placement, which is worthy of clinical promotion and application.
文摘Ensuring rib stability during pillar extraction is of prime importance in bord and pillar(B&P) method of underground coal mining with caving. Rib stability has been assessed here by way of assessing factor of safety(FOS), a ratio of the strength of rib to stress on it. Earlier formulations for rib stability when applied to case studies gave very low FOS value suggesting significant ground control problems, which were contrary to the field observations. This has necessitated the need to revisit the concept of rib stability. The stress coming on the rib is estimated with the use of numerical modeling technique using the FLAC^(3D) software. The methodology of assessing rib-stability with the help of suggested rib-strength formulation has been validated at eight Indian coal mines. The outcome of this study finds relevance and importance in ensuring underground coal liquidation with improved safety and conservation.
