Part Of Toe Research Articles

OA27 A Thrombus Tale

Abstract Introduction Non catheter related arterial thrombosis is very rare in children. Our patient had a peripheral arterial thrombus with no risk factors apart from a background of recurrent Henoch-Schönlein Purpura (HSP). He had no history of trauma. Thrombosis as a complication of HSP is extremely rare with onlyeight case reports so far in children and among those eight, there is only one resembling our case with an arterial thrombus. We considered other causes of thrombosis and screened our patient for thrombophilia, infection and malignancy. Case description Our patient, a 12-year-old boy with a background of recurrent HSP for the last two years, presented with a rash on the left 2nd toe followed by blackish discolouration of the distal part of the same toe, a few days later. His initial presentation with purpuric rash, arthralgia, and abdominal pain was diagnosed as HSP and he required no intervention required for this. He continued to have regular flares of his HSP every six weeks, and these were self-limiting. His last flare was in February 2024. In April 2024, his feet appeared dusky and mottled. He presented to his local hospital with a rash on the tip of his left 2nd toe which turned gangrenous. He was otherwise systemically well. He was initially treated with antibiotics and acyclovir as a swab from the lesions grew staphylococcus aureus and the rash was bullous initially. He was referred to our tertiary rheumatology and haematology teams at Nottingham due to worsening ischemia and an absent left dorsalis pedis pulse. His examination revealed normal blood pressure, mottled, dusky lower legs, warm left foot with a faint petechial rash near left malleolus, absent left Dorsalis pedis pulse and an ischemic tip of left 2nd toe. Bilateral femoral and upper limb pulses were well felt. His respiratory, cardiovascular, abdomen & musculoskeletal examination were normal apart from an antalgic gait. His clotting and thrombophilia screen including antiphospholipid screen was normal. His D dimer was raised at 1894ug/l. A duplex scan of his left leg showed occlusions in the distal anterior and posterior tibial artery as well as in the dorsalis pedis artery with no emboli. His inflammatory markers and autoantibodies were normal. Infection screen including mycoplasma, CMV, EBV and ASOT titres were all negative. Echo was normal. A skin biopsy from the toe revealed IgA vasculitis. Discussion We had a multidisciplinary team (MDT) discussion with haematology, vascular surgery and dermatology. As per the MDT discussion, he was given a pulse of intravenous methylprednisolone after careful consideration weighing the risk versus benefit of steroids adding to the pro thrombotic state versus active vasculitis causing narrowing of the arteries. He was also commenced on Aspirin at 1 mg/kg/day. There was marked improvement in his symptoms with improvement in the discolouration and pain, his d-dimer reduced, and he was able to mobilise comfortably. We felt that active vasculitis could be causing the vascular event. As immunology screen was negative and the skin biopsy was confirmatory of HSP. There was no thrombus specifically mentioned in the duplex but with D-dimer being raised it was a reasonable assumption was that there was a thrombus occluding the peripheral arteries. As his HSP was recurring quite frequently and was bothersome, as well as the thought that the recurrences might contribute to further vascular events and complications, we started our patient on Azathioprine. We have also sent genetic tests and awaiting a catheter angiogram to complete the investigation process. Key learning points • Consider vasculitis as one of the differentials in a child with unexplained venous or arterial thrombosis. • In a child with recurrent HSP, keep an open mind for rare complications that may occur. • Recurrent HSP in an older child may need immunosuppression. • Treatment considerations in a case with vasculitis with a thrombus has to be in close connection with haematology to decide on anticoagulation and its implications on the young person and their lifestyle. • Should there be any other investigations done or alternative diagnosis though of at this point?

Mechanism of large-scale reservoir landslides with double-sliding zones: insights from long-term field monitoring

A significant number of ancient landslides with double or multi-sliding zones exist in reservoir areas. However, understanding large-scale reservoir landslides with double-sliding zones remains limited due to the challenges of studying deformation along the sliding zone independently from surface deformation. In this study, the seepage and deformation characteristics of the Taping landslide were obtained through field investigations and long-term in-situ monitoring. For the first time, hydrological factors influencing double-sliding zones were revealed using an attribute reduction algorithm based on long-term field data. The results indicate that the Taping landslide undergoes significant step-like consistent creep deformation, exhibiting failure along double-sliding zones. For the toe part, reservoir water level (RWL) and precipitation are two critical hydrological factors triggering deformation. Shallow sliding is more susceptible to rainfall, while the deep sliding zone is more affected by RWL variations. In the rear part, precipitation has a greater impact than RWL. Daily precipitation is the primary hydrological factor affecting slope movement along the shallow sliding zone. However, accumulated precipitation over the previous seven days is the most crucial factor influencing slope movement along the deep sliding zone. During the RWL drawdown period, shallow sliding initially occurs at the toe, induced by the de-buttressing effect, while deep sliding occurs after the RWL reaches 145 m, induced by the downslope seepage force. Local damage and failure at the toe provide space for the instability of the rear part, reducing the anti-sliding force. Consequently, failure extends to the rear part. The findings of this study hold significant implications for gaining a deeper understanding of the deformation mechanisms of large-scale reservoir landslides with double-sliding zones and improving landslide management and mitigation strategies in reservoir area.

Influence of structural arrangements on static and dynamic properties of additively manufactured polyester elastomer lattice metamaterials

In the current study, we present novel carbon organic framework-inspired lattice metamaterials (CFLM) with thermoplastic polyester elastomer (TPEE) to analyze the structural effects. The CFLMs (S1, S2, S3, and SS) from TPEE were successfully produced by material extrusion (MEX) via fused-filament fabrication and had never been reported previously. In the beginning stage, static compression tests were utilized to evaluate mechanical properties, densification strain, and energy absorption, which were validated using the finite element method (FEM). According to static compression results, S2 had the largest energy absorption, followed by the SS structure. In the second stage based on the static test, dynamic sinusoidal compression was performed to calculate the dynamic elastic recovery (DER), hysteresis work absorption, and Tan δ. The results showed that the proposed lattice metamaterials showed different the hysteresis energy absorption, DER, and viscoelasticity nature from Tan δ. To apply static and dynamic compression results to shoe midsoles, they were subjected to a dynamic drop weight impact test. Based on static and dynamic compression testing, including the results of dynamic drop weight impact tests, S1 was the most suitable for the toe part of the shoe midsole, whereas SS was the best for the heel part of the shoe midsole. From the overall results of all characterizations, it was concluded that the structural effect of CFLMs successfully provided different mechanical properties in the static and dynamic tests from the signal TPEE material.

Submarine landslides on a carbonate platform slope changing transport pathways of deepwater gravity flows: Insights from the Xisha Islands, South China Sea

Landslides frequently block rivers, forming a barrier lake, resulting in a dam break event in the terrestrial environment. However, reports about the submarine landslides are scarce. Herein, the periplatform submarine landslides changing transport pathways of deepwater gravity flows within the southeastern region out of Xuande Atoll on the Xisha Islands, South China Sea, are described. Submarine landslides, including SL I and SL II, with a total area of 170.9 km2, were identified using up-to-date geophysical data, including multi-beam bathymetric and seismic data and sediment gravity cores. SL I directly connects the Sansha Canyon forming a large-scale negative relief with an area of 151.8 km2, developing the terraces, and transporting blocks and remnant blocks. SL II covers an area of 19.1 km2 and was mainly deposited on the deepwater plain with a toe part that is higher than the initial seafloor. The negative relief created by SL I on the seafloor forms the dominant pathways for the gravity flows, creating the new active channel system directly flowing into the canyon. The turbidity currents flowing along the steep lateral margin of SL II formed the cyclic steps. The remnant submarine landslide deposits on the western canyon margin indicate that SL I previously blocked the canyon and formed a submarine barrier lake, which was then eroded by the gravity flows flowing along with the channel system within SL I and the upstream canyon. Finally, the canyon was formed again, whose axis was “pushed” eastward by SL I. These observations update the evolution model of submarine landslide on a carbonate platform slope and the transport system from the slope to the submarine canyon or the deep basin and clarify the stability of submarine engineering and island-and-reef systems.

Characteristics of the clinical picture and biochemical indicators of the blood of yaks with hooves diseases in the republic of Tyva

The article deals with the issues of etiology, clinic, prevention and biochemical parameters of blood in yaks with the presence of hoof pathologies kept in various pastures: highlands and valleys. The studies were carried out on 30 (n=30) yaks with hoof pathologies kept in Ovyursky (n=15) and Mongun- Taiginsky (n=15) regions of the Republic of Tajikistan in 2021-2022. In animals with clinically pronounced pathologies, blood samples were taken for biochemical studies. The following parameters were taken into account: ALT, AST, alkaline phosphatase, total protein, albumin, globulin, creatinine, urea, calcium, phosphorus. The nature of pathological changes in the distal parts of the limbs is influenced by the sharply continental climate of the Republic of Tatarstan, a sharp change in the ground for a short time, rocky or swampy terrain. The anatomical features of the structure of the hooves are determined by the environmental conditions and the features of the static and dynamic functions of the limbs under these conditions. Compared to cattle, the horny wall of the hooves is up to 8 mm thick, the angles of the toes are more obtuse, the shape of the hoof is rounded with a horseshoe-shaped protrusion. The main pathologies of the hooves in animals kept on soft ground are deformations of the hoof horn in the form of acute-angled and curved ones. On rocky ground there are a large number of cracks and clefts concentrated on the heel parts of the wall. The consequences of injuries are inflammatory processes of an acute and chronic nature: aseptic diffuse laminitis (namins) localized on the side walls of the pelvic limbs in the area of the heels and the toe part of the sole of the chest limbs. A large number of diffuse purulent pododermatitis was found in the course of regeneration and completion of the formation of a double wall. Biochemical parameters of yak blood are characterized by an increase in the level of alanine aminotransferase, total protein, alkaline phosphatase, which is due to pathological changes in the musculoskeletal system.

Marching neuropathy of the nervus digitalis plantaris proprii medialis halluci among military personnel

Background. Marcher’s digitalgia paresthetica is a neuropathy of the medial plantar proper digital nerve (nervus digita lis plantaris proprii medialis halluci) and in some cases is accompanied by the formation of Joplin’s neuroma. Despite the general population rarity, marcher’s digitalgia paresthetica is significantly common among the special military contingent, athletes and tourists.Aim. To assess the prevalence of medial digital nerve neuropathy among military personnel and to identify possible factors contributing to its development.Materials and methods. The study involved 125 male servicemen of the Russian Federation, with an average age 37 (37–40) years. A neurological examination was performed with a detailed assessment of sensory disorders in the lower extremities, electroneuromyography and ultrasound examination of the leg nerves.Results. In 83 cases, or 66 (55–76) %, of digitalgia paresthetica were identified. Among them asymptomatic – 51 people, or 61 (47–74) %. In 27 cases – 33 (21–47) % – violation of sensitivity was observed on one side. The maximum area of violation of the sensitivity of the innervation of the medial‑plantar surface of the big toes was determined in 57 cases – 68 (55–80) %. At the same time, in 14 (6–25) % of the examined, the distal part of the second toe was additionally involved.Conclusion. In our study, the hypothesis about the influence of the type of footwear, the average daily duration of wearing and the frequency of its forced removal on the likelihood of developing paresthetic digitalgia was not confirmed. It is important that doctors are informed about the possible development of this neuropathy and its benign course.

Fatigue behavior evaluation of full-scale OSD-UHPC composite bridge deck system

To investigate the fatigue performance and fatigue damage process of the Orthotropic Steel Deck (OSD) - Ultra-High Performance Concrete (UHPC) composite bridge deck, a two-span continuous full-scale specimen was designed and tested under cyclic loading. Test results showed that the fatigue cracks firstly initiated near the lower part of the weld toe of the rib-to-cross beam welded joint, and then cracks along the weld length of the U-rib butt-welded joint developed. These observations followed by the OSD-UHPC interface debonding. The U-rib bolted joint exhibited better fatigue resistance than the U-rib butt-welded joint. The S-N curves of the rib-to-cross beam welded joint, the U-rib butt-welded joint and the U-rib bolted joint were established based on existing fatigue test data, and were compared with provisions in design codes. The S-N curves from the beam test for the short-headed stud connectors were compared with that from the push-out test. And the established S-N curves with 95% survival probability from the push-out test could be used to assess the global fatigue performance of the composite deck. Considering the durability-based critical crack width of UHPC, the established tensile S-N curve regarding critical UHPC crack width of 0.05 mm could be used to evaluate the anti-fatigue cracking ability of the UHPC layer in the composite deck system.

Developing lasts with removable toe parts for customized footwear

The scope of this work is to develop lasts with a removable toe part as one of the ways to optimize the range of lasts while maintaining a high level of conformity of the last shape to the individual measurements of the feet of customers. For this purpose, the sectional plane separating the toe part of different shapes and styles from the main back part, which corresponds to the measurements of the foot, is determined by the area of minimal deviations of the parameters of feet shapes and lasts in different 3D models. The interchange of toe parts between different lasts is carried out under the condition of a small difference between their major parameters when it is possible to perform the averaging of the shapes and dimensions of the sectional plane of different lasts without reducing the ergonomics of their shapes. The segmentation plane divides the last body in such a way that the removable toe parts can be attached to the main back parts of the lasts of different styles and forms, as well as with different heel heights, which increases the use efficiency of the replaceable elements

Design of 3D printable prosthetic foot to implement nonlinear stiffness behavior of human toe joint based on finite element analysis

Toe joint is known as one of the critical factors in designing a prosthetic foot due to its nonlinear stiffness characteristic. This stiffness characteristic provides a general feeling of springiness in the toe-off and it also affects the ankle kinetics. In this study, the toe part of the prosthetic foot was designed to improve walking performance. The toe joint was implemented as a single part suitable for 3D printing. The various shape factors such as curved shape, bending space, auxetic structure, and bending zone were applied to mimic human foot characteristics. The finite element analysis (FEA) was conducted to simulate terminal stance (from heel-off to toe-off) using the designed prosthetic foot. To find the structure with characteristics similar to the human foot, the optimization was performed based on the toe joint geometries. As a result, the optimized foot showed good agreement with human foot behavior in the toe torque-angle curve. Finally, the simulation conditions were validated by comparing with human walking data and it was confirmed that the designed prosthetic foot structure can implement the human foot function.

Failure mechanism of a slow-moving landslide on September 27, 2020, in Chang Nong Village, Guangxi, China

A recent slow-moving landslide occurred on September 27, 2020, in Chang Nong Village (24°21′ 25” N, 109°09′ 27″ E), Guangxi Province, China. The precursor activity of the landslide started approximately 5 months before landslides with cut slope construction work at the toe part of a mountain. Given this precursor, engineers set a counterweight berm at the slope’s toe for expanding toe weight to avoid further deformation. However, the measure had a negative effect on the stability of landslides, as the stabilizing berm blocked off natural groundwater channels located at the slope toe, leading to further deformation of landslides. Fortunately, monitoring of the creeping downslope movements of the landslide mass began, and an early warning was issued before the event. Thus, no casualties were caused by the slow-moving landslide; however, 72 houses were destroyed. In order to deduce the Chang Nong Village landslide failure mechanism, the geological characteristics, slope excavation schemes, rainfall data statistics, and landslide deformation patterns were systematically investigated based on unmanned aerial vehicle (UAV) photography, field investigation, displacement monitoring, and laboratory testing. The results show that colluvial stratigraphic structures and poor rock mass properties are the internal factors that induced landslides. The combined effects of prolonged heavy rainfall and the repeated fluctuation of groundwater caused by improper activities, including toe excavation and counterweight filling, are external factors that directly triggered the landslide. This case discusses how improper engineering treatment influences groundwater changes in landslide areas and supports the importance of prevention measures for colluvium landslides.

DEVELOPMENT OF A BOOT-TREE MOLD FOR MANUFACTURING RIDING BOOTS

The production of such footwear as riding boots requires additional equipment like a special mold for the formation of bootlegs, which are made using intermediate frame parts to ensure rigidity and preserving shape. The special mold of riding boots is a stylized shape of the leg from its foot to knee. The lower part corresponding to the shoe last is designed based on the parameters of the average foot, taking into account the requirements of biomechanics, physiology, and aesthetic features of the shoe style. The upper part repeats the parameters of the shin and has a specifi c asymmetrical shape, which ensures a stylish and perfect form of the riding boot. To obtain the initial data for designing the mold, there were performed anthropometric measurements of the shins of young women whose feet sizes correspond to the average ones in the selected sample. Designing of the lower part of the mold was carried out on the basis of the average parameters of the foot in Crispin LastMaker software complex using the method of reverse engineering. Designing of the general shape was performed in the PowerShape software environment by means of the features of surface, solid, and hybrid modeling. This type of boots must be made with several width-girth parameters, and the possibility to make boots with diff erent designs must be provided. Therefore, in order to e ff ectively use the molding means (a boot-tree), in the work, there was proposed the transforming mold, which allows making boots of diff erent widths and with diff erent shapes of the toe part due to its struc ture consisting of four parts changing the relative position and individual elements due to which it is possible to achieve multipurpose usage. Objective. Development of an improved shape, design, and method of designing a boot-tree molding means based on the foot 3d scan and shin measurements using the features of modern CAD software.Topicality of the work is based on the need to equip footwear production with the advanced lasts and molding means taking into account the requirements of ergonomics and fashionable design. Novelty. The proposed structure of the boot-tree developed on the basis of foot measurements is designed using a combination of reverse and direct modeling of the shape, which allows achieving the ideal and unique 3D shape combining ergonomic features and beautiful design. Such design method allows using the available digital equipment to obtain the initial data.

Классификация показателей низкого качества отображения подошвенной поверхности босых ног живых лиц

12 indicators of poor quality of papillary prints of the plantar surface of bare feet were revealed during traditional fingerprinting of living persons. Indicators are classified and arranged in chronological order as the total quantitative indicator decreases when studying 700 special fingerprint cards over two periods of time. It was concluded that the bulk of the indicators of poor quality of the plantar surface prints is associated with such indicators as prints from wet and dirty soles of the feet, repainted and smeared prints. A specific indicator only for the sole of the feet - “smeared print of the upper part of the big toe” was identified. These indicators are divided according to three more indicators for poor quality of footprints. It has been established that the quality of footprints depends on the quality of the technique and technology used to obtain them and the appropriate control by a competent person. This makes it possible to optimize measures to improve the quality of a special fingerprint card for displaying papillary prints of the plantar surface of the bare feet of living persons for comparative studies, especially when it is impossible to identify a person by the fingers and palms of the hands, as well as in connection with the use of biometric plantar terminals in the near future. Theoretical and practical recommendations for taking prints of the papillary sole of the feet are given in the development of the author’s previous works. This will affect the encoding of the image in the automatic fingerprint information system and its search characteristics, and most importantly, the final result for the prompt and objective identification of the person.

Deformation and failure of a high-steep slope induced by multi-layer coal mining

During underground mining, accurate revelation on the deformation and failure mechanisms of a high-steep slope under multi-layer mining conditions facilitates the prevention and control of geological disasters in mines. Numerical simulation based on discrete element theory can be used to explore the characteristics and mechanism of action of deformation and failure of a slope under complex geological and multi-layer mining conditions. By utilising PFC2D (particle flow code) software, the deformation and failure characteristics of a high-steep slope in Faer Coal Mine in Guizhou Province, China were investigated. Additionally, the mechanism of influence of different numbers of mining layers on the deformation and failure of the high and steep slope was elucidated. The result showed that after the goaf passed by the slope toe, multi-layer mining aggravated the subsidence and deformation of the slope toe: the slope toppled forward as it sank. The toppling of the slope changed the slope structures: the strata in the front of the slope were transformed from anti-dip to down-dip features. Extruded by collapsed–toppled rock mass, the slope toe and the rock mass located in the lower part of the slope toe generally exhibited a locking effect on the slope. Multi-layer mining degraded the overall stability of the slope, in that the total displacement of the slope was much greater than the total mining thickness of the coal seams. Based on the aforementioned research, ideas for preventing and controlling geological disasters during mining operations under a high-steep slope were proposed.

APPLICATION OF 3D MODELING METHODS TO EXTEND THE RANGE OF SHOE LASTS

A shoe last determines the inner form of a footwear. Therefore, one of the primary tasks that arise while introducing CAD of footwear is to improve the method of designing the complex surface of the shoe last (the inner form of a shoe) to provide the effi cient use of CAD functions for this aim. The variet y of modern shapes of shoe lasts complicates the task of developing their rational parameters. One of the ways to solve this problem is developing a combined shoe last that has a scientifi cally sound bac k part which includes the heel, instep and ball area, and the convertible toe part. This solution will help to fulfi ll the task of expanding the assortment range of the shoe lasts using basic ergonomic shapes. At the same time, the problem of joining two diff erent parts of a complex spatial shapes of the last is solved by using the methods of blending, morphing and construction of joining surfaces in the PowerShape software environment. Improving the range of the shoe last shapes using 3D modeling features. Scientifi c novelty. The method of modeling the ergonomic shape of a shoe last of the necessary style by combining two parts of diff erent lasts using the surface and hybrid modeling features of PowerShape software. The development of the new last shapes based on the tested ergonomic designs ensures a good combination of comfort and aesthetics, creating the preconditions for the practical implementation of the idea of a universal last with a replaceable toe part.

Form in the context of function: Fundamentals of an energy effective striding walk, the role of the plantigrade foot and its expected size.

What morphological and functional factors allow for the unique and characteristic upright striding walk of the hominin lineage? Predictive models of locomotion that arise from considering mechanisms of energy loss indicate that collision-like losses at the transition between stance limbs are important determinants of bipedal gait. Theoretical predictions argue that these collisional losses can be reduced by having "functional extra legs" which are physically the heel and the toe part of a single anatomical foot. The ideal spacing for these "functional legs" are up to a quarter of a stride length, depending on the model employed. We evaluate the foot in the context of the dynamics of a bipedal system and compare predictions of optimal foot size against empirical data from modern humans, the Laetoli footprint trackways, and chimpanzees walking bipedally. The dynamics-based modeling approach provides substantial insight into how, and why, walking works as it does, even though current models are too simple to make predictions at a level adequate to anticipate specific morphology except at the most general level.

A simple theoretical approach for analysis of slide-toe-toppling failure

A prevalent kind of failure of rock slopes is toppling instability. In secondary toppling failures, these instabilities are stimulated through some external factors. A type of secondary toppling failure is “slide-toe-toppling failure”. In this instability, the upper and toe parts of the slope have the potential of sliding and toppling failures, respectively. This failure has been investigated by an analytical method and experimental tests. In the present study, at first, the literature review of toppling failure is presented. Then a simple theoretical solution is suggested for evaluating this failure. The recommended method is compared with the approach of AMINI et al through a typical example and three physical models. The results indicate that the proposed method is in good agreement with the results of AMINI et al’s approach and experimental models. Therefore, this suggested methodology can be applied to examining the stability of slide-toe-toppling failure.

유효노치응력법을 이용한 T형 필렛 용접부의 피로수명 분석

This study aims to investigate the fatigue life of T-Type fillet welded joints for excavators subjected to bending loads, and also to verify the predicted fatigue life of the welded part using the effective notch stress method. Moreover, this study aims to determine an optimal toe angle of the T-Type fillet welded structure. In this context, the fatigue lives of T-Type fillet welded specimens (SM490A) were measured and the effective notch stress method for predicting the fatigue life of the T-Type fillet welded structure was verified by comparing with the FAT-225 curve of IIW (International Institute of Welding) as was suggested for the current types of welded structures. Considering simultaneously the scattering factor of the welded structure, the stress condition at the toe part higher than the root part, and the stress minimization condition of the toe part, the optimum toe angle at the T-Type fillet welding was identified at 30°. Likewise, the maximum stress (310.5 MPa) when the toe angle was 30° was about 14% less than the maximum stress (354.0 MPa) at 45°, and the fatigue life was improved by about 30%.

Sediment dispersal and redistributive processes in axial and transverse deep‐time source‐to‐sink systems of marine rift basins: Dampier Sub‐basin, Northwest Shelf, Australia

AbstractMorphological scaling relationships between source‐to‐sink segments have been widely explored in modern settings, however, deep‐time systems remain difficult to assess due to limited preservation of drainage basins and difficulty in quantifying complex processes that impact sediment dispersals. Integration of core, well‐logs and 3‐D seismic data across the Dampier Sub‐basin, Northwest Shelf of Australia, enables a complete deep‐time source‐to‐sink study from the footwall (Rankin Platform) catchment to the hanging wall (Kendrew Trough) depositional systems in a Jurassic late syn‐rift succession. Hydrological analysis identifies 24 drainage basins on the J50.0 (Tithonian) erosional surface, which are delimited into six drainage domains confined by NNE‐SSW trending grabens and their horsts, with drainage domain areas ranging between 29 and 156 km2. Drainage outlets of these drainage domains are well preserved along the Rankin Fault System scarp, with cross‐sectional areas ranging from 0.08 to 0.31 km2. Corresponding to the six drainage domains, sedimentological and geomorphological analysis identifies six transverse submarine fan complexes developing in the Kendrew Trough, ranging in areas from 43 to 193 km2. Seismic geomorphological analysis reveals over 90‐km‐long, slightly sinuous axial turbidity channels, developing in the lower topography of the Kendrew Trough which erodes toe parts of transverse submarine fan complexes. Positive scaling relationships exist between drainage outlet spacing and drainage basin length, and drainage outlet cross‐sectional area and drainage basin area, which indicates the geometry of drainage outlets can provide important constraints on source area dimensions in deep‐time source‐to‐sink studies. The broadly negative bias of fan area to drainage basin area ratios indicates net sediment losses in submarine fan complexes caused by axial turbidity current erosion. Source‐to‐sink sediment balance studies must be done with full evaluating of adjacent source‐to‐sink systems to delineate fans and their associated up‐dip drainages, to achieve an accurate tectonic and sedimentologic picture of deep‐time basins.

Classification of mass-transport complexes and distribution of gashydrate-bearing sediments in the northeastern continental slope of the South China Sea

The drilling areas in Shenhu and Dongsha, South China Sea, studied from 2007 to 2015, reveal great heterogeneity in the spatial distribution of the gas hydrate reservoir. Various types of mass-transport complexes (MTCs) were developed in the study areas, which served as ideal reservoirs. To conduct exploration in these areas, it is necessary to study the different types of MTCs and the corresponding gashydrate accumulations. By integrating seismic reflection and log coring data, we classified three types of MTCs according to their stress distribution: the tension, extrusion, and shear types, and their corresponding gashydrate accumulation patterns. The results show that the accumulation of the gas-hydrate varies with the type of MTC and stress distribution depending on the MTC’s position (e.g., in the headwall, translational, or toe areas). Owing to this variance of the MTC’s position, the corresponding kinemics situation in the MTCs also varies. Accordingly, we determined the corresponding location in which the gashydrate develops for various types of MTCs. Based on the bottom simulating reflectors (BSRs) and the hydrate core and image logging data, the gashydrate reservoir shows an obvious heterogeneity in various types of MTCs. The gashydrate in the tension-type MTCs are mostly borne in the toe and the headwall parts. In extrusion-type MTCs, the translational and toe parts constitute an ideal hydrate reservoir. In shear-type MTCs, the headwall and toe parts’ coarse-grained sediments show an obviously hydrate response. After comparing the gas-hydrate saturation and MTCs morphology statics data, we were able to quantitatively prove that the main factors determining gashydrate accumulation in the different types of MTCs are the fault displacement, sedimentary rate, and flow erosion rate.

Numerical Simulation of Slide-Toe-Toppling Failure Using Distinct Element Method and Finite Element Method

In blocky and layered rock slopes, toppling failure is a conventional type of instability which may occur in mining and civil engineering. If this kind of slope failure happens as a consequence of another type of failure, it is mentioned to as secondary toppling failure. “slide-toe-toppling” is a kind of secondary toppling failures, where the toe part of the slope is toppled as a consequence of a semi or non-circular sliding failure at the upper of the slope. This failure has been studied using physical modelling and analytical method. In the present study, firstly a brief review of the toppling failure in rock slopes is summarized, and the mechanism of slide-toe-toppling failure is described. Then, this failure is examined through a series of numerical modelling. Distinct element method (UDEC software) and finite element method (Phase2 software) were used in this research. Three types of slide-toe-toppling failures, including flexural, blocky, and block-flexural, are simulated. Comparison between two numerical modellings (distinct element and finite element methods) with the result of pre-existing physical models and analytical solution, illustrates that UDEC software has a better agreement than Phase2 software. This accordance indicates that this numerical code is well capable to analyze the behavior of slide-toe-toppling failure.